GB2493990A

GB2493990A - Counterweightless lifting platform assembly

Info

Publication number: GB2493990A
Application number: GB1114829.3A
Authority: GB
Inventors: Oren Meitus; Maxim Kosse
Original assignee: Electra Ltd
Current assignee: Electra Ltd
Priority date: 2011-08-26
Filing date: 2011-08-26
Publication date: 2013-02-27
Also published as: GB201114829D0

Abstract

A drive mechanism 300 for a lifting platform (400 fig. 4A) comprises a counterweightless compound pulley assembly 312 including a traction wheel 318, 320, a deflection wheel 326, 328 and a movable carriage 330 comprising a first carriage deflection wheel 332, 334, a second carriage deflection wheel 336, 338, an elongated flexible element 342, 344 looped around the wheels providing a mechanical advantage of at least 2 between the traction wheel and the carriage and a tensioning assembly 364, 366 configured to maintain the elongated flexible element 342, 344 within a predetermined range of tensions preferably by means of springs. The elongated flexible element 342, 344 may be one for more belts or cables. The drive mechanism may be associated with vertical rails (402, 404 fig. 4A). The tensioning assembly 364, 366 may apply a tensioning force to one end of the elongated flexible element 342, 344 or to a deflection wheel (fig 1D). The drive mechanism may include n electric motor which may be a gearless low speed motor or may drive a reducing gear unit. The drive mechanism may provide additional mechanical advantage (fig. 2). An overspeed car brake assembly (430 fig. 5) may be provided.

Description

LIFTING PLATFORM ASSEMBLY

Field of the invention

The invention, in some embodiments, relates to the field of lifting platforms and more particularly, but not exclusively, to lifting platforms comprising a counterweightless device comprising a tensioning assembly.

Background of the invention

Lifting platforms are occasionally constructed and used in private houses for transportation of people and goods between floors of the house. As such, lifting platforms are discriminated from elevators used by the public in high-rise buildings by several important characteristics: a lifting platform is configured to travel between a relatively small number of floors, e.g. two, or three of even four floors, and consequently it is configured to travel at a relatively low speed; a lifting platform is typically designed to carry a relatively small number of people, e.g. two or four or even eight people (typically ensuring access for use for persons with impaired mobility), which are residents of the house or visitors thereto. Further, 23 operation characteristics, such as noise or odour, and maintenance considerations, are adapted to the particular use in private houses.

In many countries the design, construction and usage parameters of lifting platforms are regulated, inter alia, by designated standards. Such is the European Standard EN 81-41 "Safety rules for the construction and installation of lifts -Special lifts for the transport of persons and goods -Part 41: Vertical lifting platforms intended for use by persons of impaired mobility". Exemplary limitations that this standard poses on lifting platforms design are an upper limit to the clear loading area of a platform of 2 square meters, and an upper limit to a lifting platform speed of 0.15 meters/second.

33 Space utilization is an important consideration in designing lifts.

Accordingly, lift designs attempt to minimize such utilized space, and in particular avoid a machinery room, especially when lifting platforms in private houses are considered. One design approach for a lifting platform which is relatively compact is based on a hydraulic system. US 4,667,775 discloses a hydraulic elevator system having a tunnel member as part of the car frame, to reduce the pit depth required for a hydraulic jack. US 6,098,759 discloses a hydraulic elevator having a hydraulic jack which acts directly on the elevator car. To reduce the amount of building work associated with this elevator concept, the hydraulic jack projects through the car floor into the car.

Despite being potentially relatively compact, a hydraulic system is disadvantageous to alternative types of systems. Major potential disadvantages are cabin positioning sensitivity to temperature variations, cumbersome maintenance and issues resulting from the use of hydraulic oil inside human residences, such as increased risk of flaming, bad odour and risk of dirt. An on-going attempt is therefore made to compact non-hydraulic systems for lifting platforms.

13 US 6,619,433 entitled "Elevator system using minimal building space" discloses an elevator system including a hoist way having a vertically adjacent structural platform, i.e., a roof slab or pit slab, that includes a recess, and a machine that fits within the recess. The vertically adjacent structural platform defines either the ceiling or floor of the hoist way. As a result of having the machine tucked into the recess in the hoist way, the machine is removed from the hoist way and the hoist way need not be expanded, either horizontally or vertically, to accommodate the machine.

US 7,108,105 discloses a cabie lift with a single compartment or shaft for housing a movable cage, and an apparatus, comprising at least one fixed winch 23 and a counterweight. For displacement of the cage, the counterweight performs travel movements shorter than those of the cage so that a pad of the shaft is always free to house the winch therein.

Summary of the invention

Aspects of the invention, in some embodiments thereof, relate to lifting platforms. More specifically, aspects of the invention, in some embodiments thereof, relate to lifting platforms comprising a counterweightless device comprising a tensioning assembly.

33 According to an aspect of some embodiments of the invention, there is provided a drive mechanism for a lifting platform, comprising a counterweightless compound pulley assembly having a top and a bottom located lower than the top.

The compound pulley assembly further includes at least one fixed traction wheel disposed at one of the top and the bottom of the compound pulley assembly, and ss at least one substantially fixed deflection wheel, disposed at the other of the top and the bottom of the compound pulley assembly. The compound pulley assembly further includes a carriage comprising at least a first carriage deflection wheel and at least a second carriage deflection wheel. The carriage is configured to be physically associated with a lifting platform car, and is movable between the top and the bottom of the compound pulley assembly. The compound pulley assembly further includes at least one elongated flexible element, having a first end and a second end. Starting from the first end, the at least one elongated flexible element is looped around the at least first carriage deflection wheel, the at least one fixed traction wheel, the at least one substantially fixed deflection wheel and the at least second carriage deflection wheel. The compound pulley assembly further includes at least one tensioning assembly functionally associated with the at least one io elongated flexible element. The at least one tensioning assembly is configured to maintain a tension of the at least one elongated flexible element in a portion thereof between the second end of the at least one elongated flexible element and the at least one fixed traction wheel, within a pre-determined range of tensions.

The drive mechanism is configured for driving a lifting platform car physically associated with the carriage, providing a mechanical advantage of at least 2 between the at least one fixed traction wheel and the carriage.

According to an aspect of some embodiments of the invention, there is provided a iffting platform, comprising at least one lifting-platform rail configured for securing to a support wall. The lifting platform further comprises a lifting-platform car, functionally associated with the at least one lifting-platform rail, and configured for moving along the at least one lifting-platform rail. The lifting-platform car includes at least a bottom platform used as a car floor. A drive mechanism according to aspects of embodiments described herein is functionally associated with the lifting-platform car by the carriage, being physically associated with the lifting platform car, for driving the lifting-platform car along the at least one lifting-platform rail.

According to an aspect of some embodiments of the invention, there is provided a building, comprising a lifting-platform support wall and a lifting platform according to aspects of embodiments described herein. The at least one lifting-platform rail of the lifting platform is secured to the lifting-platform support wall, thereby enabling the lifting platform car to move along the at least one lifting-platform rail.

In some embodiments, the at least one fixed traction wheel is mounted at the top of the compound pulley assembly, and the at least one substantially fixed deflection wheel is mounted at the bottom of the compound pulley assembly. In some embodiments, the at least one fixed traction wheel is fixedly mounted around a rotatable drive shaft, and the drive mechanism further comprises a drive assembly including an electric motor functionally associated with the drive shaft through a reducing gear unit. The motor enables controllable rotation of the drive shaft and consequently rotation of the fixed traction wheel. Controllable rotation of the fixed traction wheel controllably drives the at least one elongated flexible element, and consequently controllably drives the carriage between the top and the bottom of the compound pulley assembly.

As is discussed above, lifting platforms are often subject to a relatively low maximum speed limit by regulations and safety standards. For example, a maximum speed of 0.15 meter/second is imposed by European Standard EN 81- 13 41. Generally, low speed requires high transfer ratio between the motor driving the lifting platform and the lifting platform car. Motors, e.g. electric motors, are technically limited by a minimum revolution rate, even when employing motion control, a minimum revolution rate below which such motors can not operate properly. Providing a relatively high transter ratio, e.g. 70, by a single worm gear unit, is generally less than optimal, due to inefficiency of the gear unit and risk of gear locking.

The drive mechanism provides a mechanical advantage of at least 2 for driving the carriage by rotating the at east one fixed traction wheel. Providing a mechanical advantage of at least 2 allows use of a gear unit having a transfer 23 ratio as low as e.g. 35, and in some embodiments even lower, thus eliminating inefficiency and risk of gear locking.

In some embodiments, the elongated flexible element is a belt. A belt is an elongated flexible element having a cross-section with a ratio of width to thickness different than one. In some embodiments, the belt is a coated steel-wire belt. In some embodiments, the belt has a thickness of about 3 millimetres. In some embodiments, the at least one fixed traction wheel has a diameter not greater than about 130 millimetres, i.e. about forty times the thickness of the belt. In some embodiments an electric motor controllably rotating at a typical revolution rate of 1500 Revolutions per Minute (RPM) generates a revolution rate of about 42.86 33 RPM at the output of a reducing gear unit with a transfer ratio of 35, and in the at least one fixed traction wheel. Consequently, the belt is driven at a driving rate of about 287 millimetres per second at the at least one traction wheel. Due to a mechanical advantage of 2 provided by the drive mechanism, the carriage is controllably driven at half the speed of the belt at the at least one fixed traction wheel, equal to about 144 millimetres per second, thus conforming, for example, to European Standard EN 81-41 speed limit mentioned above.

In some embodiments, the first end of the elongated flexible element is fixed and the at least one tensioning assembly is configured to apply a force on the second end of the elongated flexible element in a direction to maintain the tension. In some embodiments, the at least one tensioning assembly comprises a spring to generate the tension. In some embodiments, the spring is a compression spring.

Maintaining the tension within a suitable range of tensions, ensures traction between the elongated flexible element and the fixed traction wheel.

Consequently, rotation of the fixed traction wheel drives the elongated flexible 13 element, thereby driving the carriage, between the top and the bottom of the compound pulley assembly. Employing a tensioning assembly such as described above to maintain a suitable tension of the elongated flexible element, avoids the need to employ a counterweight to maintain such tension, thereby requiring less space for the lifting platform shaft as is explained below. It is further noted that the compound pulley assembly does not include a drum to collect superfluous portions of the elongated flexible element, thereby requiring less space for the lifting platform shaft, compared to alternative drive mechanisms requiring a drum.

A single lifting piatform support wall is sufficient for securing the lifting platform to the building. Consequently, the lifting platform can be configured to be 23 entered and exited in any of the remaining three directions.

In some embodiments, the building further comprises a lifting platform shaft confined by at least a shaft floor, a shaft ceiling and the lifting platform support wall constructed between the shaft floor and shaft ceiling. The lifting platform shaft is configured for moving of the lifting platform car therein along the at least one lifting platform rail.

The compound pulley assembly is disposed substantially between the lifting platform support wall and the lifting platform car. Consequently, the distance between the lifting platform support wall and the lifting platform car is greater than the diameter of the first carriage deflection wheel and the second carriage 33 deflection wheel of the compound pulley assembly. Employing a belt having a width of about 3 millimetres allows employing a first carriage deflection wheel and a second carriage deflection wheel having a diameter as small as about 130 millimetres, resulting in a relatively small distance between the lifting platform support wall and the lifting platform car of about 250 millimetres.

In some embodiments, the lifting platform car is configured for moving between at least a bottom floor of the building and a top floor of the building, located above the bottom floor. The lifting platform is installed inside the lifting platform shaft so that the drive assembly is disposed substantially between the shaft ceiling and the car ceiling of the lifting platform car (when the lifting platform car resides on the top floor). Consequently, the lifting platform shaft does not need to include a machine room, and the distance between the shaft ceiling and the top floor is as low as about 2500 millimetres.

The lifting platform shaft does not need to include a pit that is considerably lower than the first floor of the building. Consequently, the shaft floor is lower than the bottom floor by a distance slightly larger than the lifting platform floor thickness (less than about 100 millimetres).

13 The small distances mentioned above, between the lifting platform support wall and the lifting platform car, between the shaft ceiling and the top floor, and between the shaft floor and the bottom floor, characterize a compact lifting platform shaft, advantageously adaptable to a private house, either under construction or even to a house that has already been constructed. Moreover, the small distances involved allow easy maintenance of the lifting platform. Accessing the drive assembly for maintenance is achieved by securing the lifting platform car on the top floor, temporarily removing the car ceiling and climbing on a small ladder from within the lifting platform car.

In some embodiments the lifting platform further comprises an overspeed 23 car brake assembly. The overspeed car brake assembly comprises a fixed brake assembly deflection wheel, disposed in proximity to the top of the compound pulley assembly. The overspeed car brake assembly further comprises a centrifugal brake assembly, comprising a brake assembly traction wheel physically associated with a centrifugal overspeed brake. The centrifugal overspeed brake is configured to brake due to centrifugal overspeed brake rotation speed exceeding a pre-determined threshold value. The centrifugal brake assembly is disposed in proximity to the bottom of the combined pulley system.

The overspeed car brake assembly further comprises a car brake, fixedly secured to the lifting-platform car and configured to brake the lifting platform car 33 by engaging with the at least one lifting platform rail when activated. The overspeed car brake assembly further comprises a looped flexible element looped around the brake assembly deflection wheel and around the brake assembly traction wheel. The looped flexible element has a portion thereof joined fixedly to the car brake, thereby moving together with the lifting platform car and rotating the brake assembly traction wheel and centrifugal overspeed brake. The looped flexible element is thereby further configured to activate the car brake subsequent to braking of the centrifugal brake assembly.

The overspeed car brake assembly further comprises a brake assembly tensioning assembly functionally associated with the centrifugal brake assembly, and configured for maintaining the looped flexible element at a tension within a pre-determined range of tensions. The centrifugal brake assembly braking subsequent to the lifting platform car speed exceeding a pre-determined threshold value, stops movement of the looped flexible element, thereby activating the car brake and braking the lifting platform car along the at least one lifting platform rail.

In some embodiments, the centrifugal brake assembly is suspended from the looped flexible element. The brake assembly tensioning assembly comprises io a load joined to the centrifugal brake assembly, thereby maintaining the looped flexible element at a tension within a pre-determined range of tensions.

The overspeed car brake assembly is particularly advantageous because the centrifugal brake assembly is disposed proximal to the bottom of the compound pulley assembly and not proximal to the top, as in alternative brake assemblies. In some embodiments, the centrifugal brake assembly disposal proximal to the bottom frees space around the top of the compound pulley assembly, thus enabling maintaining the distance between the ceiling of the lifting platform shaft and the ceiling of the biting piatform car as smail as 2500 millimetres as discussed above. Further, disposal of the centrifugal brake assembly proximal to the bottom enables easy and fast maintenance, e.g. when, following braking of the centrifugal overspeed brake, a need arises to release the centrifugal overspeed brake to resume operation of the lifting platform. Residing on the shaft floor and easily accessible from the first floor, are the centrifugal brake assembly and the tensioning assembly. Accessing the centrifugal brake assembly and the tensioning assembly is consequently achieved by securing the lifting platform car on the top floor, and stepping into the lifting platform shaft from the first floor, as is further described for example below, in reference to figure 6.

Aspects and embodiments of the invention are described in the specification herein below and in the appended claims.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the patent specification, including definitions, takes precedence.

As used herein, the terms "comprising", "including", "having" and grammatical variants thereof are to be taken as specifying the stated features, integers, steps or components but do not preclude the addition of one or more additional features, integers, steps, components or groups thereof. These terms encompass the terms "consisting of' and "consisting essentially of".

As used herein, the indefinite articles "a' and "an" mean "at least one" or "one or more" unless the context clearly dictates otherwise.

Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: 13 FIGs. 1A to 1 E schematically depict embodiments of a drive mechanism for a lifting platform comprising a counterweightless compound pulley assembly, providing a mechanical advantage of 2; FIG. 2 schematically depicts an embodiment of a drive mechanism for a lifting platform comprising a counterweightless compound pulley assembly, providing a mechanical advantage of 3; FIGs. 3A to 3C schematically depict a drive mechanism for a lifting platform; FIGs. 4A to 4C schematicaliy depict embodiments of a Hfting platform; Fig 5 schematically depicts an overspeed car brake assembly of a lifting 23 platform of Figs 4; and FIG. 6 schematically depicts a lifting platform shaft for a lifting platform.

Detailed description of the preferred embodiment(s) The principles, uses and implementations of the teachings herein may be better understood with reference to the accompanying description and figures.

Upon perusal of the description and figures present herein, one skilled in the art is able to implement the invention without undue effort or experimentation. In the figures, like reference numerals refer to like parts throughout.

33 Before explaining at least one embodiment in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth herein. The invention is capable of other embodiments or of being practiced or carried out in various ways. The phraseology and terminology employed herein are for descriptive purpose and should not be regarded as limiting.

According to an aspect of some embodiments of the invention, there is provided a drive mechanism for a lifting platform, comprising a counterweightless compound pulley assembly having a top and a bottom located lower than the top.

The compound pulley assembly further includes at least one fixed traction wheel disposed at one of the top and the bottom of the compound pulley assembly, and at least one substantially fixed deflection wheel, disposed at the other of the top and the bottom of the compound pulley assembly. The compound pulley assembly further includes a carriage comprising at least a first carriage deflection wheel and at least a second carriage deflection wheel. The carriage is configured to be physically associated with a lifting platform car and is movable between the top and the bottom of the compound pulley assembly. The compound pulley assembly 13 further includes at least one elongated flexible element, having a first end and a second end. The at least one elongated flexible element is looped around the at least first carriage deflection wheel, the at least one fixed traction wheel, the at least one substantially fixed deflection wheel, and the at least second carriage deflection wheel. The compound pulley assembly further includes at least one tensioning assembly functionally associated with the at least one elongated flexible element, configured to maintain a tension of the at least one elongated flexible element in a portion thereof between the second end of the at least one elongated flexible element and the at east one fixed traction wheei within a pre-determined range of tensions. The drive mechanism is configured for driving a 23 lifting platform car physically associated with the carriage, providing a mechanical advantage of at least 2 between the at least one fixed traction wheel and the carriage.

In some embodiments the carriage is configured to be physically associated with a lifting platform car so that a plane perpendicular to the rotation axis of the first carriage deflection wheel and including the first carriage deflection wheel, intersects the lifting platform car, for example as is described in Figure 1 B. In some embodiments the carriage is configured to be physically associated with a lifting platform car so that a plane perpendicular to the rotation axis of the first carriage deflection wheel and including the first carriage deflection wheel does not 33 intersect the lifting platform car, for example as is described in Figure 1G.

In some embodiments the first end of the at least one elongated flexible element is fixed and the at least one tensioning assembly is configured to apply a force on the second end of the at least one elongated flexible element, in a direction to maintain the tension. In some embodiments the first end and the second end of the at least one elongated flexible element are fixed, and the at least one tensioning assembly is configured to apply a force on the at least one substantially fixed deflection wheel in a direction substantially opposite to the -10 -direction of the at least one fixed traction wheel for example as is described in Figure ID.

In some embodiments the at least one tensioning assembly comprises a spring to generate the tension. In some embodiments the spring is a compression spring.

In some embodiments the at least one elongated flexible element is a cable. In some embodiments the cable is a coated cable. In some embodiments the at least one elongated exible element is a multitude of cables.

In some embodiments the at least one elongated flexible element is a belt.

13 In some embodiments the belt is a coated steel-wire belt. In some embodiments the belt has a thickness of not more than about 4 millimetres. In some embodiments the belt has a width of not less than about 30 millimetres.

In some embodiments the at least one fixed traction wheel, the first carriage deflection wheel, the second carriage deflection wheel and the at least one substantially fixed deflection wheel each has a diameter not greater than about 200 millimetres. In some embodinients the at least one fixed traction wheel, the first carriage deflection wheel, the second carriage deflection wheel and the at least one substantially fixed deflection wheei each has a diameter not greater than about 150 millimetres. In some embodiments the at least one fixed traction wheel, 23 the first carriage deflection wheel, the second carriage deflection wheel and the at least one substantially fixed deflection wheel each has a diameter not greater than about 130 millimetres. In some embodiments the at least one fixed traction wheel, the first carriage deflection wheel, the second carriage deflection wheel and the at least one substantially fixed deflection wheel all have a same diameter. In some embodiments at least one of the wheels selected from the group consisting of the at least one fixed traction wheel, the first carriage deflection wheel, the second carriage deflection wheel and the at least one substantially fixed deflection wheel has a diameter different from at least one other of the wheels of the group.

In some embodiments the at least one fixed traction wheel is mounted at 33 the top of the compound pulley assembly, and the at least one substantially fixed deflection wheel is mounted at the bottom of the compound pulley assembly. In some embodiments the at least one fixed traction wheel is mounted at the bottom of the compound pulley assembly, and the at least one substantially fixed deflection wheel is mounted at the top of the compound pulley assembly.

In some embodiments the compound pulley assembly is aligned substantially vertically, and the carriage is movable between the top and the bottom of the compound pulley assembly in a substantially vertical direction.

-11 -In some embodiments the at least one fixed traction wheel is fixedly mounted around a rotatable drive shaft, and the drive mechanism further comprises a drive assembly including an electric motor functionally associated with the drive shaft to controllably rotate the drive shaft and consequently the at least one fixed traction wheel, thereby controllably driving the at least one elongated flexible element, and consequently controllably driving the carriage between the top and the bottom of the compound pulley assembly. In some embodiments the motor is functionally associated with the drive shaft through a reducing gear unit. In some embodiments the motor is a low speed gearless io motor.

In some embodiments the carriage is controllably drivable by the motor between the top and the bottom of the compound pulley assembly at a speed not greater than about 025 meter/second. In some embodiments the carriage is controllably drivable by the motor between the top and the bottom of the compound pulley assembly at a speed not greater than about 0.15 meter/second.

In some embodiments, for example as is described in Figures 3A to 3C, the at least one fixed traction wheel includes two fixed traction wheels disposed side by side and sharing a common axis. The at least one substantiaily fixed deflection wheel includes two substantially fixed deflection wheels, disposed side by side and configured to rotate independently from one another. The at least first carriage deflection wheel includes two first carriage deflection wheels disposed side by side and configured to rotate independently from one another. The at least second carriage deflection wheel includes two second carriage deflection wheels disposed side by side and configured to rotate independently from one another.

The at least one elongated flexible element includes a first elongated flexible element having a first end and a second end. The first elongated flexible element is looped around one of the two first carriage deflection wheels, one of the two fixed traction wheels, one of the two substantially fixed deflection wheels, and one of the two second carriage deflection wheels. The at least one elongated flexible element further includes a second elongated flexible element, having a first end and a second end. The second elongated flexible element is looped around the other one of the two first carriage deflection wheels, the other one of the two fixed traction wheels, the other one of the two substantially fixed deflection wheels, and the other one of the two second carriage deflection wheels. The at least one tensioning assembly includes a first tensioning assembly functionally associated with the first elongated flexible element. The first tensioning assembly is configured to maintain a tension of the first elongated flexible element in a portion -12 -thereof between the second end of the first elongated flexible element and the one of the two fixed traction wheels, within a pre-determined range of tensions. The at least one tensioning assembly further includes a second tensioning assembly functionally associated with the second elongated flexible element. The second tensioning assembly is configured to maintain a tension of the second elongated flexible element in a portion thereof between the second end of the second elongated flexible element and the other one of the two fixed traction wheels within a pre-determined range of tensions.

In some embodiments, for example as is described in Figure 2, the at least io one fixed traction wheel is mounted on a traction wheel assembly, and the traction wheel assembly further comprises a traction wheel assembly deflection wheel, arranged coplanar with the at least one fixed traction wheel. The at least one substantially fixed deflection wheel is mounted on a deflection wheel assembly, and the deflection wheel assembly further comprises a deflection wheel assembly deflection wheel, arranged coplanar with the at least one substantially fixed deflection wheel. The at least one elongated flexible element is looped around the traction wheel assembly deflection wheel, the at least first carriage deflection wheel, the at least one fixed traction wheei, the at least one substantially fixed deflection wheel, the at least second carriage deflection wheel and the deflection wheel assembly deflection wheel. The first end of the at least one elongated flexible element and the second end of the at least one elongated flexible element are attached to the carriage. The drive mechanism thereby provides a mechanical advantage of 3 between the traction wheel and the carriage.

According to an aspect of some embodiments of the invention, there is provided a lifting platform, for example as is described in Figure 4. The lifting platform comprises at least one lifting-platform rail configured for securing to a support wall and a lifting-platform car including at least a bottom platform used as a car floor. The lifting-platform car is functionally associated with the at least one lifting-platform rail, and configured for moving along the at least one lifting-platform rail. A drive mechanism according to aspects of embodiments described herein is functionally associated with the lifting-platform car by the carriage of the drive mechanism, being physically associated with the lifting platform car, for driving the lifting-platform car along the at least one lifting-platform rail.

In some embodiments a plane perpendicular to the rotation axis of the first carriage deflection wheel and including the first carriage deflection wheel, intersects the lifting platform car for example as is described in Figure lB. In some embodiments a plane perpendicular to the rotation axis of the first carriage -13 -deflection wheel and including the first carriage deflection wheel does not intersect the lifting platform car, for example as is described in Figure 1C.

In some embodiments the at least one lifting-platform rail comprises two lifting-platform rails for example as is described in Figure 3A. In some embodiments the at least one lifting-platform rail is aligned substantially vertically, thereby allowing the lifting platform car to move in a substantially vertical direction along the at least one lifting-platform rail.

In some embodiments the lifting-platform car comprises at least one sliding guide configured to engage with the at least one lifting platform rail. In some io embodiments the at least one sliding guide is a roller sliding guide for example as is described in Figure 3B.

In some embodiments the lifting platform further comprises an overspeed car brake assembly for example as is described in Figure 5. The overspeed car brake assembly comprises a fixed brake assembly deflection wheel, disposed in proximity to the top of the compound pulley assembly. The overspeed car brake assembly further comprises a centrifugal brake assembly, disposed in proximity to the bottom of the combined pulley system. The centrifugal brake assembly comprises a brake assembly traction wheel physically associated with a centrifugal overspeed brake. The centrifugal overspeed brake is configured to brake due to centrifugal overspeed brake rotation speed exceeding a pre-determined threshold value. The overspeed car brake assembly further comprises a car brake, fixedly secured to the lifting-platform car and configured to brake the lifting platform car by engaging with the at least one lifting platform rail when activated. The overspeed car brake assembly further comprises a looped flexible element looped around the brake assembly deflection wheel and around the brake assembly traction wheel. The looped flexible element has a portion thereof joined fixedly to the car brake, thereby moving together with the lifting platform car and rotating the brake assembly traction wheel and the centrifugal overspeed brake.

The looped flexible is thereby further configured to activate the car brake subsequent to braking of the centrifugal brake assembly. The overspeed car brake assembly further comprises a brake assembly tensioning assembly functionally associated with the centrifugal brake assembly, configured for maintaining the looped flexible element at a tension within a pre-determined range of tensions. The centrifugal brake assembly braking subsequent to the lifting platform car speed exceeding a pre-determined threshold value, stops movement of the looped flexible element, thereby activating the car brake and braking the lifting platform car along the at least one lifting platform rail.

-14 -In some embodiments the centrifugal brake assembly is suspended from the looped flexible element, and the brake assembly tensioning assembly comprises a load joined to the centrifugal brake assembly thereby maintaining the looped flexible element at a tension within a pre-determined range of tensions.

According to an aspect of some embodiments of the invention, there is provided a building, comprising a lifting-platform support wall and a lifting platform according to aspects of embodiments described herein. The at least one lifting-platform rail is secured to the lifting-platform support wall, thereby enabling the lifting platform car to move along the at least one lifting-platform rail, for example io as is described in Figure 6.

In some embodiments the lifting platform is configured to be entered and exited in at least two substantially different directions. In some embodiments the lifting platform is configured to be entered and exited in three substantially different directions.

In some embodiments the lifting platform car is configured for moving between at least a bottom floor of the building and a top floor of the building, located above the bottom floor.

In some embodiments the lifting platform support wall is substantially vertical. In some embodiments the at least one lifting-platform rail is aligned substantially vertically, thereby allowing the lifting platform car to move in a substantially vertical direction.

In some embodiments the building further comprises a lifting platform shaft confined by at least a shaft floor and the lifting platform support wall, constructed above the shaft floor. The lifting platform shaft is configured for moving of the lifting platform car therein along the at least one lifting platform rail.

In some embodiments the shaft floor is lower than the bottom floor by no more than about 120 millimetres. In some embodiments the support wall is distanced from the lifting platform car by no more than about 260 millimetres.

In some embodiments the building further comprises a shaft ceiling constructed above the lifting platform support wall and confining the lifting platform shaft from above. In some embodiments the shaft ceiling is higher than the top floor by no more than about 2600 millimetres.

Figure 1A schematically depicts an embodiment of a drive mechanism 100 for a lifting platform. Drive mechanism 100 includes a counterweightless compound pulley assembly 102, having a top 104 and a bottom 106 located lower than top 104. Compound pulley assembly 102 further includes a fixed traction wheel 108, disposed at top 104, and a substantially fixed deflection wheel 110, -15 -disposed at bottom 106. Compound pulley assembly 102 further includes a carriage 112, including a first carriage deflection wheel 114 and a second carriage deflection wheel 116 and configured to be physically associated with a payload 118, such as a lifting platform car.

Compound pulley assembly 102 further includes an elongated flexible element 120, having a first end 122 attached to a fixed point 124 proximal to top 104, and a second end 126. Starting from first end 122, elongated flexible element is looped around first carriage deflection wheel 114, fixed traction wheel 108, substantially fixed deflection wheel 110 and second carriage deflection wheel 116.

io Compound pulley assembly 102 further includes a tensioning assembly 128, functionally associated with elongated flexible element 120 at second end 126 and physically attached to a fixed point 130. Tensioning assembly 128 includes a compression spring 132, configured to be compressed to apply a force FT on second end 126, to maintain elongated flexible element 120 at a tension T=FT.

Maintaining the tension I within a suitable range of tensions, ensures traction between elongated flexible element 120 and fixed traction wheel 108.

Consequentiy, rotation of fixed traction wheei 108 drives elongated flexible element 120, thereby driving carriage 112, between top 104 and bottom 106 of compound pulley assembly 102. Employing a tensioning assembly such as e.g. tensioning assembly 128 to maintain a suitable tension of elongated flexible element 120, avoids the need to employ a counterweight to maintain such tension, thereby requiring less space for a lifting platform shaft, as is further explained and detailed below. It is further noted that compound pulley assembly 100 does not include a drum to collect superfluous portions of elongated flexible element 120, thereby requiring less space for a lifting platform shaft, compared to alternative drive mechanisms requiring a drum.

Drive mechanism 100 provides a mechanical advantage of 2 for suspending carriage 112 and driving carriage 112 by rotating fixed traction wheel 108. A mechanical advantage of 2 enables carriage 112 to be lifted together with associated payload 118, by applying a force on flexible element 120 by fixed traction wheel 108, wherein the force is equal to or greater than about half the total weight of carriage 112 and associated payload 118. Further, a mechanical advantage of 2 enables carriage 112 to be driven at half the speed at which elongated flexible element 120 is driven at, at fixed traction wheel 108.

Figure 1 B schematically depicts a top view of carriage 112, first carriage deflection wheel 114 and payload 118 of drive mechanism 100 (not showing -16 -elongated flexible element 120). Payload 118 is arranged relative to first carriage deflection wheel 114 so that a plane 138 perpendicular to the rotation axis of first carriage deflection wheel 114 and including first carriage deflection wheel 114, intersects payload 118. Figure 1C schematically depicts a top view of carriage 112, first carriage deflection wheel 114 and payload 118 of an embodiment of a drive mechanism 140 (not showing elongated flexible element 120). Drive mechanism 140 differs from drive mechanism 100 in that plane 138 perpendicular to the rotation axis of first carriage deflection wheel 114 and including first carriage deflection wheel 114 of drive mechanism 140 does not intersect payload 118.

io Figure 1 D schematically depicts a bottom section of an alternative embodiment of a drive mechanism 150 and a counterweightless compound pulley assembly 152. Compound pulley assembly 152 differs from compound pulley assembly 102 of Figure 1A in that tensioning assembly 128 is associated with substantially fixed deflection wheel 110, instead of being associated with second end 126 of elongated flexible element 120, as in Figure 1A. To maintain a tension Tin elongated flexible element 120 of compound pulley assembly 152, tensioning assembly 128 applies a force FT=2T on substantially fixed deflection wheel 110, in a direction opposite to the direction of the fixed traction wheel (not shown).

Subsequent to maintaining tension in elongated flexible element 120 by tensioning assembly 128, second end 126 of elongated flexible element 120 of compound pulley assembly 152 is secured to a fixed point 130. In compound pulley assembly 152, substantially fixed deflection wheel 110 is not fixed in one place but is rather substantially fixed. Substantially fixed means that substantially fixed deflection wheel 110 is movable only to a small extent by tensioning assembly 128, as required to maintain tension of elongated flexible element 120.

Figure 1 E schematically depicts another embodiment of a drive mechanism for a lifting platform, comprising a counterweightless compound pulley assembly 172. Compound pulley assembly 172 differs from compound pulley assembly 102 of Figure 1A in that fixed traction wheel 108 is disposed at bottom 106, and substantially fixed deflection wheel 110 is disposed at top 104.

Figure 2 schematically depicts an embodiment of a drive mechanism 200 for a lifting platform. Drive mechanism 200 includes a counterweightless compound pulley assembly 202, having a top 204 and a bottom 206 located lower than top 204. Compound pulley assembly 202 further includes a traction wheel assembly 208 fixed at top 204 and a deflection wheel assembly 210 fixed at bottom 206. Traction wheel assembly 208 includes fixed traction wheel 108 and a traction wheel assembly deflection wheel 212, arranged coplanar with fixed -17 -traction wheel 108, meaning that fixed traction wheel 108 and traction wheel assembly deflection wheel 212 are substantially on a same geometric plane.

Deflection wheel assembly 210 includes substantially fixed deflection wheel 110 and a deflection wheel assembly deflection wheel 214, arranged coplanar with substantially fixed deflection wheel 110.

Compound pulley assembly 202 further includes carriage 112, including first carriage deflection wheel 114 and second carriage deflection wheel 116, and configured to be physically associated with payload 118. Compound pulley assembly 202 further includes elongated flexible element 120, having first end 122 io physically associated with carriage 112, and second end 126. Starting from first end 122, elongated flexible element 120 is looped around traction wheel assembly deflection wheel 212, first carriage deflection wheel 114, fixed traction wheel 108, substantially fixed deflection wheel 110, second carriage deflection wheel 116 and deflection wheel assembly deflection wheel 214.

Compound pulley assembly 202 further includes a tensioning assembly 128, functionally associated with elongated flexible element 120 at second end 126 and physically attached to carriage 112, thereby applying a force FT on second end 126, in a direction to maintain elongated flexible element 120 at a tension T=FT.

Drive mechanism 200 provides a mechanical advantage of 3 for suspending carriage 112 and driving carriage 112 by rotating fixed traction wheel 108. A mechanical advantage of 3 enables carriage 112 to be lifted together with associated payload 118, by applying a force on flexible element 120 by fixed traction wheel 108, wherein the force is equal to or greater than about one-third of the total weight of carriage 112 and associated payload 118. Further, a mechanical advantage of 3 enables carriage 112 to be driven at one-third the speed at which elongated flexible element 120 is driven at fixed traction wheel 108.

Figure 3A schematically depicts an embodiment of a drive mechanism 300 for a lifting platform. Drive mechanism 300 includes a drive assembly 302 such as model K0532 from Series K helical bevels by Benzlers Limited, including an electric motor 304 functionally associated with a reducing gear unit 306. Drive assembly 302 is depicted schematically in detail also in Figure 3B. Reducing gear unit 306 is a helical type gear, physically associated with a drive shaft 308 for outputting rotational motion. Drive assembly 302 is mounted on a top frame 310, configured to be fixedly secured as is explained further below in Figure 4A, thereby fixing drive assembly 302.

-18 -Drive mechanism 300 further includes a counterweightless compound pulley assembly 312 aligned vertically and having a top 314 and a bottom 316 located substantially below top 314. Compound pulley assembly 312 includes two fixed traction wheels, 318 and 320, disposed side by side at top 314 and fixedly mounted on drive shaft 308, providing a common axis and thereby fixing fixed traction wheels 318 and 320. Compound pulley assembly 312 further includes a base 322 comprising a cage 324. Base 322 is disposed at bottom 316 and configured to be fixedly secured as is explained further below in Figure 4A, and Compound pulley assembly 312 further includes two substantially fixed deflection 13 wheels, 326 and 328, disposed side by side and rotatably secured to base 322 thereby being fixed in place and allowed to rotate independently from one another.

Compound pulley assembly 312 further includes a carriage 330, including two first carriage deflection wheels 332 and 334, disposed side by side and configured to rotate independently from one another, and two second carriage deflection wheels, 336 and 338, disposed side by side and configured to rotate independently from one another. Carriage 330 is configured to be physically associated with a lifting platform car (not shown) using screws (not shown) and screw holes 340.

Compound pulley assembly 312 further includes a first flat belt 342, and a 23 second flat belt 344, each having a first end, 346 and 348, respectively, and a second end, 350 and 352, respectively. First ends 346 and 348 are secured by top wedge sockets 354 and 356, respectively, and second ends 350 and 352 are secured by bottom wedge sockets 358 and 360, respectively. Starting from first end 346, first flat belt 342 is looped around one of first carriage deflection wheels 332, one of fixed traction wheels 318, one of substantially fixed deflection wheels 326 and one of second carriage deflection wheels 336. Starting from first end 348, second flat belt 344 is looped around the other one of first carriage deflection wheels 334, the other one of fixed traction wheels 320, the other one of substantially fixed deflection wheels 328 and the other one of second carriage 33 deflection wheels 338.

Figure 3B schematically depicts a top section of compound pulley assembly 312, not showing flat belts 342 and 344. A U frame 362 is fixedly secured to top frame 310, and top wedge sockets 354 and 356 are fixedly secured to U frame 362, thereby fixing first ends 346 and 348 (not shown) of flat belts 342 and 344 (not shown).

Compound pulley assembly 312 further includes a first tensioning assembly 364 and a second tensioning assembly 366, as is schematically depicted in Figure -19 - 3C. First tensioning assembly 364 and second tensioning assembly 366 are secured in cage 324 and configured to function independently from one another.

Bottom wedge sockets 358 and 360 are functionally associated with first tensioning assembly 364 and with second tensioning assembly 366, respectively.

Each tensioning assembly 364 and 366 includes a compression spring 368 and 370, respectively, functionally associated with bottom wedge sockets 358 and 360, respectively. First tensioning assembly 364 applies a force on bottom wedge sockets 358, thereby applying a force on second end 350 of first flat belt 342 in a direction to maintain a desired tension of first flat belt 342. Second tensioning io assembly 366 applies a force on bottom wedge sockets 360 thereby applying a force on second end 352 of second flat belt 344 in a direction to maintain a desired tension of second flat belt 344. First tensioning assembly 364 and second tensioning assembly 366, are configured to apply a stronger force on bottom wedge sockets 358 and 360, respectively, when compression springs 368 and 370, respectively, are more compressed.

Each tensioning assembly 364 and 366, further includes a compression sensor, 372 and 374, respectively, configured to detect an expansion of the respective compression spring, 368 and 370, beyond a predetermine point, and, when activated, to send an electric signal braking the operation of electric motor 304.

Compound pulley assembly 312 is assembled with compression springs 368 and 370 maximally compressed, for example as is demonstrated by compression spring 370 in Figure 3C, thus affecting a maximum allowed tension in flat belts 342 and 344. In the course of operation of drive mechanism 300, flat belts 342 and 344 may be subject to slight elongation due to stress, leading to expansion of compression springs 368 and 370, as is demonstrated for example by compression spring 368 in Figure 3C, leading in turn to a consequent decrease of the tension in flat belts 342 and 344. If elongation of a flat belt, 342 or 344, exceeds a predetermined extent (or if a flat belt 342 or 344, is accidentally torn), leading to subsequent expansion of the respective compression spring 368 or 370, the respective expansion sensor, 372 or 374 is activated and stops operation of electric motor 304. In case one of flat belts 342 and 344 is torn or otherwise does not provide suspension to carriage 330, the other flat belt may still provide the required suspension for driving carriage 330 or holding carriage 330 (together with an associated payload) in place.

According to some embodiments drive mechanism 300 further includes strain sensors 376 and 378, as is schematically depicted in Figure 3B. Strain -20 -sensors 376 and 378 are secured to U-frame 362 and each is functionally associated with top wedge sockets 354 and 356, respectively. Each strain sensor 376 and 378 is electrically associated with an electric control circuit (not shown) controlling drive mechanism 300, thereby configured to output a strain measurement to the electric control circuit. Strain sensor 376 is configured to sense the strain applied by top wedge socket 354, and strain sensor 378 is configured to sense the strain applied by top wedge socket 356. The strain applied by top wedge sockets 354 and 356 on strain sensors 376 and 378 is substantially equal to the tension of flat belts 342 and 344 (not shown), io respectively, between carriage 330 and top wedge sockets 354 and 356, respectively.

According to some embodiments flat belts 342 and 344 are coated steel wire belts, as is described for example in US 6,401,871. Coated steel wire flat belts 342 and 344 have a thickness of about 3 millimetres and a width of about 60 millimetres. According to some embodiments, the tension of flat belts 342 and 344 during operation is between about 450Kg and about 750 Kg.

Lifting platforms are often subject to a relatively low maximum speed limit by regulations and safety standards. For example, a maximum speed of 0.15 meter/second is imposed by European Standard EN 81-41. Generally, low speed requires high transfer ratio between the motor driving the lifting platform and the lifting platform car, because motors, e.g. electric motors, are technically limited by a minimum revolution rate, below which such motors can not operate properly.

Providing a relatively high transfer ratio, e.g. 70, by a single worm gear unit, is generally less than optimal, due to inefficiency of the gear unit and risk of gear locking.

Drive mechanism 300 provides a mechanical advantage of 2 for driving carriage 330 by rotating fixed traction wheels 318 and 320, thus allowing gear unit 306 having a transfer ratio as low as e.g. 35. According to some embodiments, the diameter of fixed traction wheels 318 and 320 is about 128 millimetres, about forty times the thickness of flat belts 342 and 344 (the diameter of a traction wheel is defined here as the diameter of the contact surface between the wheel and the associated cable or belt). Consequently, electric motor 304, controllably rotating at a typical revolution rate of 1500 Revolutions per Minute (RPM) generates a revolution rate of about 42.86 RPM in fixed traction wheels 318 and 320, leading to a driving rate of about 287 millimetres per second of flat belts 342 and 344 at traction wheels 342 and 344. Due to the mechanical advantage of 2 provided by drive mechanism 300, carriage 330 is controllably driven in such a situation at half -21 -the speed of flat belts 342 and 344 at fixed traction wheels 318 and 320, equal to about 144 millimetres per second, thus conforming, for example, to European Standard EN 81-41 speed limit mentioned above.

According to some embodiments drive assembly 302 includes a low-speed gearless motor such as TMR-ELE-01 of Hiwin Corporation, rather than model K0532 described above. Low-speed gearless motor such as TMR-ELE-01 produces a controlled linear speed of about 0.23 meters/sec of carriage 330 when using a traction wheel diameter of 128 millimetres. Equivalently, a low-speed gearless motor such as TMR-ELE-01 can produce a linear speed of about 0.15 io meters/sec of carriage 112, when driving a drive mechanism such as 200 of Figure 2.

Figure 4A schematically depicts an embodiment of a lifting platform 400 comprising drive mechanism 300 of figure 3A. Lifting platform 400 further includes two lifting platform rails, 402 and 404, aligned parallel to each other along the vertical direction, and secured to top frame 310 and to base 322 of compound pulley assembly 312. Lifting platform rails 402 and 404 are further configured for securing to a vertical support wall (not shown), through wall mounts 406, thereby fixing top frame 310, drive assembly 302 and base 322.

Lifting platform 400 further includes a lifting platform car 410, configured for carrying persons, including a bottom platform used as a car floor 412, a car ceiling 414, two car side walls 416 and 418, and a car back wall 420. Lifting platform car 400 is physically associated with carriage 330 of compound pulley assembly 312, so that a plain perpendicular to the axis of rotation of first carriage deflection wheel (not shown) and including first carriage deflection wheel, intersects lifting platform car 410. Lifting platform car 410 is thereby controllably drivable by drive mechanism 300 between top 314 and bottom 316 of compound pulley assembly 312.

Lifting platform car 410 further includes four roller sliding guides 422, such as model HSM RG 80x20 by ACLA-WERKE GMBH, secured to lifting platform car 410, depicted in detail in Figure 4B. Two of four roller sliding guides 422 are configured to engage with lifting platform rail 402, and the other two of four roller sliding guides 422 are configured to engage with lifting platform rail 404, by sliding up and down along lifting platform rails 402 and 404 and substantially preventing motion of lifting platform car 410 sideways or back and forth. Sliding of roller sliding guides 422 along lifting platform rails 402 and 404 enables lifting platform car 410 to move along lifting platform rails 402 and 404 in a substantially vertical direction.

-22 -Lifting platform 400 further includes an overspeed car brake assembly 430, schematically depicted in detail in Figure 5. Overspeed car brake assembly 430 comprises a fixed brake assembly deflection wheel 432, rotatably mounted on a brake assembly deflection wheel base 434. Brake assembly deflection wheel base 434 is securely fixed to top base 310 in Figure 4A, proximal to top 314 of compound pulley assembly 312.

Overspeed car brake assembly 430 further comprises a centrifugal brake assembly 436 comprising a brake assembly traction wheel 438, a centrifugal overspeed brake 440 and a centrifugal brake assembly base 442. Brake assembly io traction wheel 438 is physically associated with centrifugal overspeed brake 440, and both are rotatably mounted on centrifugal brake assembly base 442.

Centrifugal overspeed brake 440 rotates together with brake assembly traction wheel 438 and is configured to brake rotation following centrifugal overspeed brake 440 rotation speed exceeding a predetermined threshold value.

Overspeed car brake assembly 430 further comprises a car brake 444 fixedly secured to lifting platform car 410 of Figure 4A. Car brake 444 comprises a brake handle 446 configured to activate car brake 444, and two brakes 448, configured to brake lifting platform car 410 by engaging with lifting piatform rails 402 and 404 when car brake 444 is activated by brake handle 446.

Overspeed car brake assembly 430 further comprises a looped cable 450, looped around fixed brake assembly deflection wheel 432 and around brake assembly traction wheel 438 so that centrifugal brake assembly 436 is suspended on looped cable 450, proximal to bottom 316 of compound pulley assembly 312. A portion of looped cable 450 is joined fixedly to handle 446 of car brake 444, and is thereby moved together with lifting platform car 410 as lifting platform car 410 moves along lifting platform rails 402 and 404. Looped cable 450 is further configured to activate car brake 444 by pulling brake handle 446.

Overspeed car brake assembly 430 further comprises a brake assembly tensioning assembly 452, comprising a load 454 secured to centrifugal brake assembly base 442, thereby exerting a force on looped cable 450 in a downward direction due to gravity, and ensuring a desired tension in looped cable 450. Brake assembly tensioning assembly 452 further comprises two anchored posts 456 mounted on a tensioning assembly base 458. Tensioning assembly base 458 is configured to be fixedly secured to base 322 of compound pulley assembly 312 of Figure 4A, so that anchored posts 456 are aligned vertically. Load 454 comprises two channels 460, configured to receive anchored posts 456 thereby allowing load 454 to slide up and down along anchored posts 456 substantially without any side -23 -movement, when load 454, together with centrifugal brake assembly 436, are suspended above tensioning assembly base 458 and between anchored posts 456. Brake assembly tensioning assembly 452 further comprises a loose cable sensor 462, attached to tensioning assembly base 458 under load 454 and configured to electrically brake operation of electric motor 304 of drive mechanism 302 upon detection of descent of load 454 beyond a predetermined point. If looped cable 450 elongates beyond a predetermined threshold, or if looped cable 450 is accidentally torn, then load 454 descends along anchored posts 456, thereby activating loose cable sensor 462 and consequently braking operation of io electric motor 304.

During operation, lifting platform car 410 moves looped cable 450 as lifting platform car 410 moves up and down along lifting platform rails 402 and 404, thereby affecting a rotation of brake assembly traction wheel 438 and centrifugal overspeed brake 440. If lifting platform car 410 exceeds a speed limit, e.g. due to accidental tear of flat belts 342 and 344, centrifugal overspeed brake 440 brakes, thereby stopping movement of looped cable 450. Stopping movement of looped cable 450 while lifting platform car 410 is still moving, pulls brake handle 446, thereby activating car brake 444 and affecting full braking of lifting platform car 410.

Overspeed car brake assembly 430 is particularly advantageous because centrifugal brake assembly 436 is disposed proximal to bottom 316 of compound pulley assembly 312, and not proximal to top 314 as in alternative brake assemblies. In some embodiments, the centrifugal brake assembly disposal proximal to the bottom frees space around the top of the compound pulley assembly, thus enabling maintaining the distance between the ceiling of the lifting platform shaft and the ceiling of the lifting platform car as small as 2500 millimetres, for example as discussed below, in reference to Figure 6. In some embodiments, centrifugal brake assembly 436 disposal proximal to bottom 316 enables easy and fast maintenance, e.g. when, following braking of centrifugal overspeed brake 440, a need arises to release centrifugal overspeed brake 440 to resume operation of lifting platform 400, as is further described in detail, in reference to figure 6 below.

Lifting platform 400 further comprises a safety lock 470 depicted in Figure 4C, for securing lifting platform car 410 at a pre-defined location along lifting platform rails 402 and 404. Safety lock 470 is configured for preventing free fall of lifting platform car 410 when not suspended by flat belts 342 and 344, e.g. when flat belts 342 and 344 are disassembled from compound pulley assembly 312.

-24 -Safety lock 470 comprises a metal block 472 configured to be manually secured to one of lifting platform rails 402 and 404 at a predefined location thereon using a screw 474. For use, lifting platform car 410 is moved to a desired upper location along lifting platform rails 402 and 404, and metal block 472 is secured to one of lifting platform rails 402 and 404 below roller sliding guides 422 using screw 474, thus preventing lifting platform car 410 from sliding down along lifting platform rails 402 and 404.

Figure 6 schematically depicts an embodiment of a lifting platform 400 installed in a lifting platform shaft 600 of a building (not shown), in accordance io with the teachings herein. Lifting platform shaft 600 is confined within a shaft floor 602, a shaft ceiling 604, vertical shaft walls 606 and 608, a vertical lifting platform support wall 610 and a vertical shaft front wall 612, all four walls constructed above shaft floor 602, whereas shaft ceiling 604 confines lifting platform shaft 600 from above. Lifting platform 400 is secured to lifting platform support wall 610 using wall mounts 406, so that rails 402 and 404 are aligned vertically, and lifting platform car 410 moves in a substantially vertical direction inside lifting platform shaft 600.

Lifting platform car 410 is configured to move between a bottom fioor 614 and a top floor 616 of the building. Shaft vertical front wall 612 has a lower opening 618 and an upper opening 620, configured to be used for entering and exiting lifting platform car 410 on bottom floor 614 and on top floor 616, respectively. A single lifting platform support wall is sufficient for securing lifting platform 400 to the building. Consequently, in some embodiments, lifting platform 400 can be configured to be entered and exited in the remaining three directions, that is to say, in any one, and in any two, and even in all the three substantially different directions associated with shaft walls 606 and 608, and with front wall 612.

Lifting platform 400 is installed inside lifting platform shaft 600 so that compound pulley assembly 312 is disposed substantially in a back space 622 between lifting platform support wall 610 and lifting platform car 410.

Consequently, the distance between lifting platform support wall 610 and lifting platform car 410 is greater than the diameter of first carriage deflection wheels and second carriage deflection wheels (not shown) of compound pulley assembly 312. Employing flat belts 342 and 344 having a width of about 3 millimetres allows employing first carriage deflection wheels and second carriage deflection wheels having a diameter as small as about 128 millimetres, resulting in a relatively -25 -compact back space 622. The distance between lifting platform support wall 610 and lifting platform car 410 in lifting platform shaft 600 is about 250 millimetres.

Lifting platform 400 is installed inside lifting platform shaft 600 so that drive assembly 302 is disposed substantially in a top space 624 between shaft ceiling 604 and car ceiling 414 of lifting platform car 410 when lifting platform car resides on top floor 616. Consequently the distance between shaft ceiling 604 and top floor 616 in lifting platform shaft 600 is about 2500 millimetres. Further, shaft floor 602 is lower than bottom floor 614 by a distance larger than the thickness of car floor 412, of about 100 millimetres.

13 The small distances mentioned above, between lifting platform support wall 610 and lifting platform car4lO, between shaft ceiling 604 and top floor 616 and between shaft floor 602 and bottom floor 614, characterize a compact lifting platform shaft, advantageously adaptable to a private house, either under construction or even to a house that has already been constructed. Moreover, the small distances involved allow easy maintenance of lifting platform 400. Residing on shaft floor 602 and easily accessible from first floor 614, are centrifugal brake assembly 436 (not shown) comprising centrifugal overspeed brake 440, and two tensioning assembHes 364 and 366 (not shown). Accessing centrifugai brake assembly 436 and tensioning assemblies 364 and 366 is consequently achieved 23 by securing lifting platform car 410 on second floor 616 using safety lock 470 (not shown) as described above, and stepping into lifting platform shaft 600 from first floor 614. Further, Accessing drive assembly 302 for maintenance is achieved by securing lifting platform car 410 on second floor 616 as described above, temporarily removing car ceiling 414 and climbing on a small ladder from within lifting platform car 410.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, 33 may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to -26 -embrace all such alternatives, modifications and variations that fall within the scope of the appended claims.

Citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the invention.

Section headings are used herein to ease understanding of the specification and should not be construed as necessarily limiting.

Claims

<claim-text>-27 -CLAIMS1. A drive mechanism for a lifting platform, comprising a counterweightless compound pulley assembly having a top, a bottom located lower than said top, and including: at least one fixed traction wheel disposed at one of said top and said bottom of said compound pulley assembly; at least one substantially fixed deflection wheel, disposed at the other of said top and said bottom of said compound pulley assembly; io a carriage comprising at least a first carriage deflection wheel and at least a second carriage deflection wheel, configured to be physically associated with a lifting platform car and movable between said top and said bottom of said compound pulley assembly; at least one elongated flexible element, having a first end and a second end, looped around said at least first carriage deflection wheel, said at least one fixed traction wheel, said at least one substantially fixed deflection wheel, and said at least second carriage deflection wheel; and at least one tensioning assembiy functionally associated with said at least one elongated flexible element, configured to maintain a tension of said at least one elongated flexible element in a portion thereof between said second end of said at least one elongated flexible element and said at least one fixed traction wheel within a pre-determined range of tensions, wherein the drive mechanism is configured for driving a lifting platform car physically associated with said carriage, providing a mechanical advantage of at least 2 between said at least one fixed traction wheel and said carriage.</claim-text> <claim-text>2. A drive mechanism according to claim 1, wherein said carriage is configured to be physically associated with a lifting platform car so that a plane perpendicular to the rotation axis of said first carriage deflection wheel and including said first carriage deflection wheel intersects said lifting platform car.</claim-text> <claim-text>3. A drive mechanism according to claim 1 wherein said carriage is configured to be physically associated with a lifting platform car so that a plane perpendicular to the rotation axis of said first carriage deflection wheel and including said first carriage deflection wheel does not intersect said lifting platform car.</claim-text> <claim-text>-28 - 4. A drive mechanism according to any of claims 1 to 3, wherein said first end of said at least one elongated flexible element is fixed and said at least one tensioning assembly is configured to apply a force on said second end of said at least one elongated flexible element in a direction to maintain said tension.</claim-text> <claim-text>5. A drive mechanism according to any of claims 1 to 3, wherein said first end and said second end of said at least one elongated flexible element are fixed and said at least one tensioning assembly is configured to apply a force on said at least one substantially fixed deflection wheel in a direction substantially io opposite to the direction of said at least one fixed traction wheel.</claim-text> <claim-text>6. A drive mechanism according to any of claims 1 to 5, wherein said at least one tensioning assembly comprises a spring to generate said tension.</claim-text> <claim-text>7. A drive mechanism according to claim 6, wherein said spring is a compression spring.</claim-text> <claim-text>8. A drive mechanism according to any of claims I to 7, wherein said at least one elongated flexible element is a cable.</claim-text> <claim-text>9. A drive mechanism according to any of claims 1 to 7, wherein said at least one elongated flexible element is a multitude of cables.</claim-text> <claim-text>10. A drive mechanism according to claim 8, wherein said cable is a coated cable.</claim-text> <claim-text>11. A drive mechanism according to any of claims 1 to 7, wherein said at least one elongated flexible element is a belt.</claim-text> <claim-text>12. A drive mechanism according to claim 11, wherein said belt is a coated steel-wire belt.</claim-text> <claim-text>13. A drive mechanism according to any of claims 11 and 12, wherein said belt has a thickness of not more than about 4 millimetres.</claim-text> <claim-text>14. A drive mechanism according to any of claims 11 to 13, wherein said belt has a width of not less than about 30 millimetres.</claim-text> <claim-text>-29 - 15. A drive mechanism according to any of claims 1 to 14, wherein said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at least one substantially fixed deflection wheel each has a diameter not greater than about 200 millimetres.</claim-text> <claim-text>16. A drive mechanism according to any of claims 1 to 15, wherein said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at least one substantially fixed deflection wheel each has a diameter not greater than about 150 millimetres.</claim-text> <claim-text>17. A drive mechanism according to any of claims 1 to 16, wherein said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at least one substantially fixed deflection wheel each has a diameter not greater than about 130 millimetres.</claim-text> <claim-text>18. A drive mechanism according to any of claims 1 to 17, wherein said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at east one substantiaily fixed deflection wheel all have a same diameter.</claim-text> <claim-text>19. A drive mechanism according to any of claims 1 to 17, wherein at least one of the wheels selected from the group consisting of said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at least one substantially fixed deflection wheel has a diameter different from at least one other of said wheels of said group.</claim-text> <claim-text>20. A drive mechanism according to any of claims 1 to 19, wherein said at least one fixed traction wheel is mounted at said top of said compound pulley assembly, and said at least one substantially fixed deflection wheel is mounted at 33 said bottom of said compound pulley assembly.</claim-text> <claim-text>21. A drive mechanism according to any of claims 1 to 19, wherein said at least one fixed traction wheel is mounted at said bottom of said compound pulley assembly, and said at least one substantially fixed deflection wheel is mounted at said top of said compound pulley assembly.</claim-text> <claim-text>-30 - 22. A drive mechanism according to any of claims 1 to 21, wherein said compound pulley assembly is aligned substantially vertically, and said carriage is movable between said top and said bottom of said compound pulley assembly in a substantially vertical direction.</claim-text> <claim-text>23. A drive mechanism according to any of claims 1 to 22 wherein said at least one fixed traction wheel is fixedly mounted around a rotatable drive shaft, and the drive mechanism further comprises a drive assembly including an electric motor functionally associated with said drive shaft to controllably rotate said drive io shaft and consequently said at least one fixed traction wheel, thereby controllably driving said at least one elongated flexible element, and consequently controllably driving said carriage between said top and said bottom of said compound pulley assembly.</claim-text> <claim-text>24. A drive mechanism according to claim 23, wherein said motor is functionally associated with said drive shaft through a reducing gear unit.</claim-text> <claim-text>25. A drive mechanism according to claim 23, wherein said motor is a low speed gearless motor.</claim-text> <claim-text>26. A drive mechanism according to any of claims 23 to 25, wherein said carriage is controllably drivable by said motor between said top and said bottom of said compound pulley assembly at a speed not greater than about 0.25 meter/second.</claim-text> <claim-text>27. A drive mechanism according to any of claims 23 to 25, wherein said carriage is controllably drivable by said motor between said top and said bottom of said compound pulley assembly at a speed not greater than about 0.15 meter/second 28. A drive mechanism according to any of claims 1 to 27, wherein: said at least one fixed traction wheel includes two fixed traction wheels disposed side by side and sharing a common axis; said at least one substantially fixed deflection wheel includes two substantially fixed deflection wheels, disposed side by side and configured to rotate independently from one another; -31 -said at least first carriage deflection wheel includes two first carriage deflection wheels disposed side by side and configured to rotate independently from one another; said at least second carriage deflection wheel includes two second carriage deflection wheels disposed side by side and configured to rotate independently from one another; said at least one elongated flexible element includes a first elongated flexible element having a first end and a second end, said first elongated flexible element looped around one of said two first carriage deflection wheels, one of said io two fixed traction wheels, one of said two substantially fixed deflection wheels, and one of said two second carriage deflection wheels, and said at least one elongated flexible element further includes a second elongated flexible element, having a first end and a second end, said second elongated flexible element looped around the other one of said two first carriage deflection wheels, the other one of said two fixed traction wheels, the other one of said two substantially fixed deflection wheels, and the other one of said two second carriage deflection wheels; and said at least one tensioning assembly includes a first tensioning assembly functionally associated with said first elongated flexible element and configured to maintain a tension of said first elongated flexible element in a portion thereof between said second end of said first elongated flexible element and said one of said two fixed traction wheels within a pre-determined range of tensions, and said at least one tensioning assembly further includes a second tensioning assembly functionally associated with said second elongated flexible element and configured to maintain a tension of said second elongated flexible element in a portion thereof between said second end of said second elongated flexible element and the other one of said two fixed traction wheels within a pre-determined range of tensions.29. A drive mechanism according to claim 1, wherein: said at least one fixed traction wheel being mounted on a traction wheel assembly, said traction wheel assembly comprising a traction wheel assembly deflection wheel arranged coplanar with said at least one fixed traction wheel; said at least one substantially fixed deflection wheel being mounted on a deflection wheel assembly, said deflection wheel assembly comprising a deflection wheel assembly deflection wheel arranged coplanar with said at least one substantially fixed deflection wheel; -32 -said at least one elongated flexible element is looped around said traction wheel assembly deflection wheel, said at least first carriage deflection wheel, said at least one fixed traction wheel, said at least one substantially fixed deflection wheel, said at least second carriage deflection wheel and said deflection wheel assembly deflection wheel, and said first end of said at least one elongated flexible element and said second end of said at least one elongated flexible element are attached to said carriage, thereby providing a mechanical advantage of at least 3 between said io traction wheel and said carriage.30. A lifting platform, comprising: at least one lifting-platform rail configured for securing to a support wall; functionally associated with said at least one lifting-platform rail, a lifting-platform car including at least a bottom platform used as a car floor, and configured for moving along said at least one lifting-platform rail; and functionally associated with said lifting-platform car, a drive mechanism of any of claims I to 29, wherein said carriage of said drive mechanism is physically associated with said lifting platform car, for driving said lifting-platform car along said at least one lifting-platform rail.31. A lifting platform according to claim 30, wherein a plane perpendicular to the rotation axis of said first carriage deflection wheel and including said first carriage deflection wheel intersects said lifting platform car.32. A lifting platform according to claim 30, wherein a plane perpendicular to the rotation axis of said first carriage deflection wheel and including said first carriage deflection wheel does not intersect said lifting platform car.33. A lifting platform according to any of claims 30 to 32, wherein said at least one lifting-platform rail comprises two lifting-platform rails.34. A lifting platform according to any of claims 30 to 33, wherein said lifting-platform car comprises at least one sliding guide configured to engage with said at least one lifting platform rail.-33 - 35. A lifting platform according to claim 34 wherein said at least one sliding guide is a roller sliding guide.36. A lifting platform according to any of claims 30 to 35 wherein said at least one lifting-platform rail is aligned substantially vertically, thereby allowing said lifting platform car to move in a substantially vertical direction along said at least one lifting-platform rail.13 37. A lifting platform according to any of claims 30 to 36 further comprising an overspeed car brake assembly, comprising: a fixed brake assembly deflection wheel, disposed in proximity to said top of said compound pulley assembly; a centrifugal brake assembly, comprising a brake assembly traction wheel physically associated with a centrifugal overspeed brake, configured to brake due to centrifugal overspeed brake rotation speed exceeding a pre-determined threshold value, disposed in proximity to said bottom of said combined pulley system; a car brake, fixedly secured to said lifting-platform car and configured to 23 brake said lifting platform car by engaging with said at least one lifting platform rail when activated; a looped flexible element looped around said brake assembly deflection wheel and around said brake assembly traction wheel and having a portion thereof joined fixedly to said car brake, thereby moving together with said lifting platform car and rotating said brake assembly traction wheel and centrifugal overspeed brake, and configured to activate said car brake subsequent to braking of said centrifugal brake assembly; and a brake assembly tensioning assembly functionally associated with said centrifugal brake assembly, configured for maintaining said looped flexible 33 element at a tension within a pre-determined range of tensions, wherein said centrifugal brake assembly braking subsequent to said lifting platform car speed exceeding a pre-determined threshold value, stops movement of said looped flexible element, thereby activating said car brake and braking said lifting platform car along said at least one lifting platform rail.38. A lifting platform according to claim 37, wherein said centrifugal brake assembly is suspended from said looped flexible element, and said brake -34 -assembly tensioning assembly comprises a load joined to said centrifugal brake assembly thereby maintaining said looped flexible element at a tension within a pre-determined range of tensions.39. A building, comprising: a lifting-platform support wall; and a lifting platform according to any of claims 30 to 38, wherein said at least one lifting-platform rail is secured to said lifting-platform support wall thereby enabling said lifting platform car to move along said at least io one lifting-platform rail.40. A building according to claim 39 wherein said lifting platform car is configured for moving between at least a bottom floor of said building and a top floor of said building, located above said bottom floor.41. A building according to any of claims 39 and 40 wherein said lifting platform support wall is substantially vertical.42. A building according to any of claims 39 to 41 wherein said at least one lifting-platform rail is aligned substantially vertically, thereby allowing said lifting platform car to move in a substantially vertical direction.43. A building according to any of claims claim 39 to 42, further comprising a lifting platform shaft confined by at least a shaft floor and said lifting platform support wall constructed above said shaft floor, said lifting platform shaft configured for moving of said lifting platform car therein along said at least one lifting platform rail.44. A building according to claim 43 wherein said shaft floor is lower than said bottom floor by no more than about 120 millimetres.45. A building according to any of claims 39 to 44 wherein said support wall is distanced from said lifting platform car by no more than about 260 millimetres.-35 - 46. A building according to any of claims 43 to 45 further comprising a shaft ceiling constructed above said lifting platform support wall and confining said lifting platform shaft from above.47. A building according to claim 46 wherein said shaft ceiling is higher than said top floor by no more than about 2600 millimetres.48. A building according to any of claims 39 to 47 wherein said lifting platform is configured to be entered and exited in at least two substantially io different directions.49. A building according to claim 48 wherein said lifting platform is configured to be entered and exited in three substantially different directions.Amendments to the claims have been made as follows:CLAIMS1. A traction drive mechanism for a lifting platform, comprising a counterweightiess compound pulley assembly having a top, a bottom located lower than said top, and including: -at least one fixed traction wheel disposed at one of said top and said bottom of said compound pulley assembly; -at least one substantially fixed deflection wheel, disposed at the other of said top and said bottom of said compound pulley assembly; -a carriage comprising at least a first carriage deflection wheel and at least a second carriage deflection wheel, configured to be physically associated with a lifting platform car so that said carriage deflection wheels are arranged sidewise to said lifting platform car, said carriage being movable between said top and said bottom of said compound pulley assembly; -at least one elongated flexible element, having a first end and a second end, looped around said at least first carriage deflection wheel, said at least one fixed traction wheel, said at least one substantially fixed deflection wheel, and said at least second carriage deflection wheel, so that said elongated flexible element is wrapped around said at least first carriage deflection wheel. said at least one fixed traction wheel, said at least one substantially fixed deflection wheel and said at least second carriage deflection wheel in a same direction; and -at least one tensioning assembly fbnctionally associated with said at least one elongated flexible element, configured to maintain a tension of said at least one elongated flexible element in a portion thereof between said second end of said at least one elongated flexible element and said at least one fixed traction wheel within a pre-determined range of tensions, ensuring traction between said elongated flexible element and said fixed traction wheel, wherein the drive mechanism is configured for driving a lifting platform car physically associated with said carriage, providing a mechanical advantage of at least 2 between said at least one fixed traction wheel and said carriage.
2. A drive mechanism according to claim I, wherein said carriage is configured to be physically associated with a lifting platform car so that a plane perpendicular to the rotation axis of said first carriage deflection wheel and including said first carriage deflection wheel intersects said lifting piatform car.
3. A drive mechanism according to claim 1, wherein said carriage is configured to be physically associated with a lifting platform car so that a plane perpendicular to the rotation axis of said first carriage deflection wheel and including said first carriage deflection wheel does not intersect said lifting platform car.
4. A drive mechanism according to any of claims I to 3, wherein said first end of said at least one elongated flexible element is fixed and said at least one tensioning assembly is configured to apply a force on said second end of said at least one elongated flexible element in a direction to maintain said tension.
5. A drive mechanism according to any of claims I to 3, wherein said first end and said second end of said at least one elongated flexible element are fixed and said at least one tensioning assembly is configured to apply a force on said at least one substantially fixed deflection wheel in a direction substantially opposite to the direction of said at least one fixed traction wheel.
6. A drive mechanism according to any of claims 1 to 5, wherein said at least one tensioning assembly comprises a spring to generate said tension.
7. A drive mechanism according to claim 6, wherein said spring is a compression spring.
8. A drive mechanism according to any of claims 1 to 7, wherein said at least one elongated flexible element is a cable.
9. A drive mechanism according to any of claims 1 to 7, wherein said at least one elongated flexible element is a multitude of cables.
10. A drive mechanism according to claim 8, wherein said cable is a coated cable,
11. A drive mechanism according to any of claims I to 7, wherein said at least one elongated flexible element is a belt.
12. A drive mechanism according to claim 11, wherein said belt is a coated steel-wire belt.
13. A drive mechanism according to any of claims 11 and 12, wherein said belt has a thickness of not more than about 4 millimeters.
14, A drive mechanism according to any of claims 11 to 13, wherein said belt has a width of not less than about 30 millimeters.
15. A drive mechanism according to any of claims I to 14, wherein said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at least one substantially fixed deflection wheel each has a diameter not greater than about 200 millimeters.
16. A drive mechanism according to any of claims 1 to 15, wherein said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at least one substantially fixed deflection wheel each has a diameter not greater than about 150 millimeters.
17. A drive mechanism according to any of claims 1 to 16, wherein said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at least one substantially fixed deflection wheel each has a diameter not greater than about 130 millimeters.
18. A drive mechanism according to any of claims 1 to 17, wherein said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at least one substantially fixed deflection wheel all have a same diameter.
19, A drive mechanism according to any of claims I to 17, wherein at least one of the wheels selected from the group consisting of said at least one fixed traction wheel, said first carriage deflection wheel, said second carriage deflection wheel and said at least one substantially fixed deflection wheel has a diameter different from at least one other of said wheels of said group.
20. A drive mechanism according to any of claims 1 to 19, wherein said at least one fixed traction wheel is mounted at said top of said compound pulley assembly, and said at least one substantially fixed deflection wheel is mounted at said bottom of said compound pulley assembly and said first end of said at least one elongated flexible element is fixed directly below said fixed traction wheel.
21. A drive mechanism according to any of claims 1 to 19, wherein said at least one fixed traction wheel is mounted at said bottom of said compound pulley assembly, and said at least one substantially fixed deflection wheel is mounted at said top of said compound pulley assembly.
22. A drive mechanism according to any of claims I to 21, wherein said compound pulley assembly is aligned substantially vertically, and said carriage is movable between said top and said bottom of said compound pulley assembly in a substantially vertical direction,
23. A drive mechanism according to any of claims 1 to 22 wherein said at least one fixed traction wheel is fixedly mounted around a rotatable drive shaft, and the drive mechanism ifirther comprises a drive assembly including an electric motor functionally associated with said drive shaft to controllably rotate said drive shaft and consequently said at least one fixed traction wheel, thereby controllably driving said at least one elongated flexible element, and consequently controllably driving said carriage between said top and said bottom of said compound pulley assembly.
24. A drive mechanism according to claim 23, wherein said motor is functionally associated with said drive shaft through a reducing gear unit.
25. A drive mechanism according to claim 23, wherein said motor is a low speed gearless motor.
26. A drive mechanism according to any of claims 23 to 25, wherein said carriage is controllably drivable by said motor between said top and said bottom of said compound pulley assembly at a speed not greater than about 0.25 meter/second.
27. A drive mechanism according to any of claims 23 to 25, wherein said carriage is controllably drivable by said motor between said top and said bottom of said compound pulley assembly at a speed not greater than about 0.15 meter/second.
28. A drive mechanism according to any of claims I to 27 wherein: -said at least one fixed traction wheel includes two fixed traction wheels disposed side by side and sharing a common axis; -said at least one substantially fixed deflection wheel includes two substantially fixed deflection wheels, disposed side by side and configured to rotate independently from one another; -said at least first carriage deflection wheel includes two first carriage deflection wheels disposed side by side and configured to rotate independently from one another; -said at least second carriage deflection wheel includes two second carriage deflection wheels disposed side by side and configured to rotate independently from one another; -said at least one elongated flexible element includes a first elongated flexible element having a first end and a second end, said first elongated flexible element looped around one of said two first carriage deflection wheels, one of said two fixed traction wheels, one of said two substantially fixed deflection wheels, and one of said two second carriage deflection wheels, and said at least one elongated flexible element further includes a second elongated flexible element, having a first end and a second end, said second elongated flexible element looped around the other one of said two first carriage deflection wheels, the other one of said two fixed traction wheels, the other one of said two substantially fixed deflection wheels, and the other one of said two second carriage deflection wheels; and -said at least one tensioning assembly includes a first tensioning assembly functionally associated with said first elongated flexible element and configured to maintain a tension of said first elongated flexible element in a portion thereof between said second end of said first elongated flexible element and said one of said two fixed traction wheels within a pre-determined range of tensions, ensuring traction between said first elongated flexible element and said one of said two fixed traction wheels, and said at least one tensioning assembly further includes a second tensioning assembly functionally associated with said second elongated flexible clement and configured to maintain a tension of said second elongated flexible element in a portion thereof between said second end of said second elongated flexible element and the other one of said two fixed traction wheels within a pre-determined range of tensions, ensuring traction between said second elongated flexible clement and said other of said two fixed traction wheels.
29, A drive mechanism according to claim 1 wherein -said at least one fixed traction wheel being mounted on a traction wheel assembly, said traction wheel assembly comprising a traction wheel assembly deflection wheel arranged coplanar with said at least one fixed traction wheel; -said at least one substantially fixed deflection wheel being mounted on a deflection wheel assembly, said deflection wheel assembly comprising a deflection wheel assembly deflection wheel arranged coplanar with said at least one substantially fixed deflection wheel; -said at least one elongated flexible element is looped around said traction wheel assembly deflection wheel, said at least first carriage deflection wheel, said at least one fixed traction wheel, said at least one substantially fixed deflection wheel, said at least second carriage deflection wheel and said deflection wheel assembly deflection wheel, so that said elongated flexible element is wrapped around said traction wheel assembly deflection wheel, said at least first carriage deflection wheel, said at least one fixed traction wheel, said at least one substantially fixed deflection wheel, said at least second carriage deflection wheel and said deflection wheel assembly deflection wheel in a same direction, and -said first end of said at least one elongated flexible element and said second end of said at least one elongated flexible element are attached to said carriage, thereby providing a mechanical advantage of at least 3 between said fraction wheel and said carriage.
30. A lifting platform, comprising: -at least one lifting-platform rail configured for securing to a support wall; -Ibnctionally associated with said at least one lifting-platform rail, a lifting-platform car including at least a bottom platform used as a car floor, and configured for moving along said at least one lifting-platform rail; and -ftinctionally associated with said lifting-platform car, a drive mechanism of any of claims 1 to 29, wherein said carriage of said drive mechanism is physically associated with said lifting platform car so that said carriage deflection wheels are arranged sidewise to said lifting platform car, for driving said lifting-platfonn car along said at least one lifting-platform rail.
31. A lifting platform according to claim 30, wherein a plane perpendicular to the rotation axis of said first carriage deflection wheel and including said first carriage deflection wheel intersects said lifting platform car.
32. A lifting platform according to claim 30, wherein a plane perpendicular to the rotation axis of said first carriage deflection wheel and including said first carriage deflection wheel does not intersect said lifting platform car.
33. A lifting platform according to any of claims 30 to 32, wherein said at least one lifting-platfonn rail comprises two lifting-platform rails.
34. A lifting platform according to any of claims 30 to 33, wherein said lifting-platform car comprises at least one sliding guide configured to engage with said at least one lifting platform rail.
35. A lifting platform according to claim 34 wherein said at least one sliding guide is a roller sliding guide.
36. A lifting platform according to any of claims 30 to 35 wherein said at least one lifting-platform rail is aligned substantially vertically, thereby allowing said lifting platform car to move in a substantially vertical direction along said at least one lifting-platform rail, 37, A lifting platform according to any of claims 30 to 36 fUrther comprising an overspeed car brake assembly, comprising: -a fixed brake assembly deflection wheel, disposed in proximity to said top of said compound pulley assembly; -a centriftigal brake assembly, comprising a brake assembly traction wheel physically associated with a centrifugal overspeed brake, configured to brake due to centrifugal overspeed brake rotation speed exceeding a pre-determined threshold value, disposed in proximity to said bottom of said combined pulley system; -a car brake, fixedly secured to said lifting-platform car and configured to brake said lifting platform car by engaging with said at least one lifting platform rail when activated; -a looped flexible element looped around said brake assembly deflection wheel and around said brake assembly traction wheel and having a portion thereof joined fixedly to said car brake, thereby moving together with said lifting platform car and rotating said brake assembly traction wheel and centrifugal overspeed brake, and configured to activate said car brake subsequent to braking of said centrifugal brake assembly; and -a brake assembly tensioning assembly functionally associated with said centrifugal brake assembly, configured for maintaining said looped flexible element at a tension within a pre-determined range of tensions; wherein said centrifugal brake assembly braking subsequent to said lifting platform car speed exceeding a pre-determined threshold value, stops movement of said looped flexible element, thereby activating said car brake and braking said lifting platform car along said at least one lifting platform rail.38. A lifting platform according to claim 37, wherein said centrifugal brake assembly is suspended from said looped flexible element, and said brake assembly tensioning assembly comprises a load joined to said centrifugal brake assembly thereby maintaining said looped flexible element at a tension within a pre-determined range of tensions.39. A building, comprising: -a lifting-platform support wall; and -a lifting platform according to any of claims 30 to 38, wherein said at least one lifting-platform rail is secured to said lifting-platform support wall thereby enabling said lifting platform car to move along said at least one lifting-platform rail.40. A building according to claim 39 wherein said lifting platform car is configured for moving between at least a bottom floor of said building and a top floor of said building, located above said bottom floor.41. A building according to any of claims 39 and 40 wherein said lifting platform support wall is substantially vertical.42. A building according to any of claims 39 to 41 wherein said at least one lifting-platform rail is aligned substantially vertically, thereby allowing said lifting platform car to move in a substantially vertical direction.43. A building according to any of claims claim 39 to 42, further comprising a lifting platform shaft confined by at least a shaft floor and said lifting platform support wall constructed above said shaft floor, said lifting platform shaft configured for moving of said lifting platform car therein along said at least one lifting platform rail.44. A building according to claim 43 wherein said shaft floor is lower than said bottom floor by no more than about 120 millimeters.45. A building according to any of claims 39 to 44 wherein said support wall is distanced from said lifting platform car by no more than about 260 millimeters.46. A building according to any of claims 43 to 45 further comprising a shaft ceiling constructed above said lifting platform support wall and confining said lifting platform shaft from above.47, A building according to claim 46 wherein said shaft ceiling is higher than said top floor by no more than about 2600 millimeters.48, A building according to any of claims 39 to 47 wherein said lifting platform is configured to be entered and exited in at least two substantially different directions.49. A building according to claim 48 wherein said lifting platform is configured to be entered and exited in three substantially different directions,</claim-text>