EP4261178A1

EP4261178A1 - Lifting system

Info

Publication number: EP4261178A1
Application number: EP23167861.6A
Authority: EP
Inventors: Nicola Michelin
Original assignee: Key Automation Srl
Current assignee: Key Automation Srl
Priority date: 2022-04-13
Filing date: 2023-04-13
Publication date: 2023-10-18
Also published as: IT202200007397A1

Abstract

Lifting system (10), comprising at least one column (11a, 11b, 11c, 11d, 11e) along which at least two sliders (13a, 13b) can slide by means of corresponding drive means (12), each of the at least two sliders being provided with a support (14a) for at least one load.

Description

FIELD OF THE INVENTION

The present invention concerns the sector of lifting systems, used in particular to lift and store loads such as vehicles, for example cycles, motorcycles or suchlike, for maintenance or storage purposes, or other types of means, objects, materials or other, too heavy to be lifted manually.

BACKGROUND OF THE INVENTION

Lifting systems are used to lift loads for various purposes, for example to free up space on the ground, or for storage during periods of non-use, or other.
Document US-A-2020122988 describes a lifting system substantially provided with at least one column along which one or more sliders are positioned, associated with supports for loads, such as platforms or suchlike. The loads positioned on the platforms could also be kept lifted for a long time, until it is necessary to pick them up, thus obtaining a sort of store.
For lifting, the system can be equipped with an electric winch, the metal cable of which is connected to a main slider on which a loading platform is located. Possibly, other sliders can be connected to the main slider "in cascade", with corresponding platforms, secured to the main one by means of cables or belts. By driving the winch, the cable lifts or lowers the main slider and its platform, and any other sliders and platforms connected to it.
For safety reasons, the system has a self-retaining and anti-sliding system able to prevent the platforms, loaded by the weight of the objects, from falling down to the ground when not in use, in stationary conditions, or in the event of a fault, with negative consequences.
Generally, this function is entrusted directly to the winch, and in particular to an electric motor of the "self-braking" type, that is, equipped with a parking brake. This is a device whose braking action occurs in the absence of current; after completing the maneuver of ascent or descent, a solenoid, or excitation coil, stops exerting its force on an anchor, which, thrust by one or more springs, compresses the brake disc thus exerting the braking action.
This system is widespread and reliable enough, but the wear on the braking disc, the loss of the elastic characteristics of the springs or their breakage could compromise its effectiveness, with catastrophic effects both for the integrity of the materials lifted and also for those people who at that moment might be passing under the platforms, which can also be of significant size and weight, for example in the case where the stored load is a motorcycle.
For this reason, winch manufacturers generally specify that their systems are designed to lift loads only for the time strictly necessary to move them, but that once the movement is complete, they must be immediately put in a safe position on the ground or on stable supports. No guarantee is given on the duration of the braking action and its effectiveness over time.
An analogous negative result could occur, even with a perfectly efficient brake, if one of the gears of the winch reduction unit were to fail, or the steel cable that supports the applied load were to break.
There is therefore a need to perfect a lifting system which can overcome at least one of the disadvantages of the state of the art.
In particular, one purpose of the present invention is to provide a lifting system which is reliable and safe, even in the event of a malfunction of the means that lift the load along the column, for example an electric winch or other.
Another purpose of the present invention is to provide a lifting system which guarantees high safety both during lifting of the load and also in stationary conditions, following a stoppage, in any position along its travel.
Another purpose of the present invention is to provide a lifting system which guarantees high safety even when the load is stored for a long time at any height and which therefore avoids the risk of accidental falls of the support, for example a platform or other, where said load is positioned.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claim. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.
In accordance with the above purposes, a lifting system according to the present invention comprises a single column along which at least two sliders, overlapping with each other and reciprocally distanced, can slide by means of corresponding drive means, the sliders being provided with a support for at least one load.
According to one characteristic aspect of the invention, the column comprises fastening, or gripping, elements along its extension and the slider located higher on the column comprises a safety device provided with a stop element, which is configured to snap-engage, that is, fasten, with at least one of the fastening elements by means of elastic means which tend to keep it under pressure toward the column in a stable position, and therefore keep the slider stationary at least in descent. The safety device is also provided with an unclamping element, associated with the stop element and configured to overcome the force of the elastic means and therefore free the stop element from the fastening element with which it is engaged, so as to allow the sliders a downward motion along the column. Moreover, the slider below is connected to the slider located higher on the column by means of connection elements.
The fastening elements can be slots created along the column, or elements that are raised or recessed with respect to the surfaces of the column, or a combination of these elements, or suchlike. The surfaces of the column in which the fastening elements are provided can be one or more of either the front surface, the lateral surfaces, the rear surface. The raised or recessed elements can also form part of a rack installed on the column and with a sawtooth-shaped profile, or suchlike, to create the raised or recessed elements.
Thanks to this safety device, the present lifting system proves to be extremely reliable and safe, even in the event of a malfunction of the means for lifting the load along the column, for example an electric winch or other.
This lifting system also guarantees high safety both during the ascent to lift the load as well as in stationary conditions, following a stop, in any position whatsoever along its travel.
Furthermore, the present lifting system guarantees high safety even in the situation the load is stored for a long period at any height whatsoever, and therefore prevents the risk of accidental falls of the support, for example a platform or other, where the load is positioned.
According to another aspect of the invention, only the higher located slider has the safety device, and the other one or more sliders are attached to the higher slider by means of cables or belts.
According to another aspect of the invention, the stop element is a stop lever comprising at one end at least one tooth configured to engage with at least one of the fastening elements.
According to another aspect of the invention, the stop lever comprises one or several rotating components and it is configured, thanks to the rotation around a pin attached to the slider and to the action of the elastic means, to assume a first stable clamping position, that is, engaged with at least one of the fastening elements with the rotating components abutting against a first striker, and a second stable unclamping position, in which it is disengaged from the fastening elements and the rotating components abut against another striker.
According to another aspect of the invention, the stop lever comprises an elongated hole by means of which it engages on a fixed pin.
According to another aspect of the invention, the stop lever comprises, at the end opposite to the one by means of which it engages in at least one of the fastening elements, a mobile pin on which there is pivoted a reset lever which is configured to automatically reset the safety device.
According to another aspect of the invention, the reset lever comprises a first end configured to engage with the mobile pin and provided with a tooth configured to abut against a striker, a second end opposite to the first end in which there is positioned a suitably shaped reset tooth configured to abut against the surface of the column, and elastic means wound around the pin and configured to keep the tooth against the striker.
According to one variant, the pin on which the reset lever is pivoted is fixed and does not form part of the stop lever. The fixed pin of the reset lever can be associated with, or project from, a protection casing associated with the higher located slider and the reset lever can cooperate with the fixed pin. The fixed pin can function as an abutment for the reset lever.
The end of the stop lever, opposite to the one by means of which it engages in/with at least one of the fastening elements, is configured to engage on a mobile pin which can oscillate in a slot-shaped seating.
The mobile pin is distinct with respect to the pin on which the reset lever is pivoted.
Advantageously, the mobile pin is associated with the protection casing.
The reset lever is rotatably associated with the fixed pin, wherein a first end of the reset lever is configured to engage with the mobile pin, while an opposite second end of the reset lever is configured to abut against the column or to engage with the fastening elements, and wherein elastic means are associated with the reset lever in order to return it to a stable position between one oscillation and the other.
According to another aspect of the invention, the unclamping element comprises a cable provided with a terminal secured between attachment pins or elements, which are integral with the stop lever.
According to another aspect of the invention, the stop lever is formed by two parts, or grips, between which the reset lever is at least partly inserted.
According to another aspect of the invention, the stop element comprises a pin configured to snap-engage, by means of the elastic means, with at least one of the fastening elements.
According to another aspect of the invention, the pin comprises, at the lower part, a surface configured to abut against a striker of the fastening elements, and, at the upper part, an inclined plane configured to slide on an inclined plane made on the fastening elements.
According to another aspect of the invention, the safety device comprises the protection casing associated with the slider.

DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

fig. 1 is a three-dimensional view of a lifting system according to the present invention;
fig. 2 is a lateral and longitudinal section view of a safety device provided in the lifting system;
fig. 3 is an enlarged longitudinal section view of the safety device;
fig. 4 is a three-dimensional view of the safety device;
fig. 5 is another view of the safety device provided with a casing;
fig. 6 is another three-dimensional and partly sectioned view of the safety device;
figs. 7a-7j are lateral and partly longitudinal section views of some operating phases of the safety device;

figs. 8a, 8b are, respectively, a three-dimensional view and a longitudinal section view of a first embodiment of a column of the present lifting system;
figs. 9a, 9b are, respectively, a three-dimensional view and a longitudinal section view of a second embodiment of the column;
figs. 10a, 10b are, respectively, a three-dimensional view and a longitudinal section view of a third embodiment of the column;
figs. 11a, 11b are, respectively, a three-dimensional view and a longitudinal section view of a fourth embodiment of the column;
figs. 12a, 12b are, respectively, a three-dimensional view and a front view of a fifth embodiment of the column;
fig. 13a is a lateral and longitudinal section view of a variant of the safety device of the present lifting system in a clamping position;
fig. 13b is a lateral and longitudinal section view of the safety device of fig. 13a in an unclamping position;
figs. 14a-14c show a variant of the safety device provided in the lifting system according to the present invention.

We must clarify that in the present description the phraseology and terminology used, as well as the figures in the attached drawings also as described, have the sole function of better illustrating and explaining the present invention, their function being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.
To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.

DESCRIPTION OF SOME EMBODIMENTS

We will now refer in detail to the possible embodiments of the invention, of which one or more examples are shown in the attached drawings, by way of a non-limiting illustration. The phraseology and terminology used here is also for the purposes of providing non-limiting examples.
With reference to the attached drawings, see in particular fig. 1, fig. 2 and fig. 3, a lifting system 10 according to the present invention comprises a single column 11a along which at least two sliders 13a, 13b provided with a corresponding support 14a, 14b for at least one load can slide, by means of corresponding drive means 12. The supports 14a, 14b can be a platform, possibly removable, or other.
The column 11a can be provided with a pedestal 20 and possibly with bars 21 in order to be fixed to a wall or ceiling. The lifting system 10 can provide several columns 11a along which several sliders 13a, 13b are positioned sliding, overlapping with each other and reciprocally distanced, provided with several supports 14a, 14b. Two sliders 13a, 13b are shown by way of example in the drawing; however, the number could be even greater. The column 11a can have any suitable height and can be formed by several elements 48 joined telescopically, by interlocking or in any other manner, thus assuming a modular conformation.
Along its extension the column 11a comprises a series of fastening elements 15a and the slider 13a comprises a safety device 16 provided with a stop lever 17 configured to snap-engage, that is, fasten, with at least one of the fastening elements 15a by means of elastic means 18. The elastic means 18 tend to keep the stop lever 17 under pressure toward the column 11a in a stable position, and therefore the slider 13a stationary at least in descent. The safety device 16 is also provided with an unclamping element 19 associated with the stop lever 17 and configured to overcome the force of the elastic means 18 and therefore free the stop lever 17 from the fastening element 15a, so as to allow the slider 13a a downward motion along the column 11a.
The fastening elements 15a are preferably equidistant along the column 11a.
If the lifting system 10 provides several reciprocally integral sliders 13a, 13b, it is sufficient that only the slider 13a located higher is provided with the safety device 16. The slider 13b below can in fact be connected to the slider 13a by means of connection elements 45 such as metal cables, straps or other. However, the slider 13b could be equipped with its own safety device 16.
The stop lever 17, see in particular fig. 3, comprises at one end 46 at least one tooth 22 configured to engage in at least one of the fastening elements 15a. The tooth 22 can be hook-shaped so as to allow the upward motion of the slider 13a along the column 11a, but prevent its descent. In particular, the tooth 22 can have a curvilinear profile in an upward direction and a substantially flat or slightly concave surface in a downward direction, by means of which it comes into contact with the edge of the fastening element 15a, for example a slit. At the end of the tooth 22, a roller 30 can also be provided able to facilitate its upward sliding. In proximity to the tooth 22, the stop lever 17 can be provided with a damping element 37, such as a rubber or suchlike, configured to limit the intensity of the strike of the stop lever 17 on the surface of the column 11a. The damping element 37 is positioned in particular on the side of the tooth 22 opposite to the side in which it has the curvilinear profile.
The stop lever 17 comprises, in particular at the end 46, one or more rotating components 23 and it is configured, thanks to the rotation around a pin 26 fixed to the slider 13a and to the action of the elastic means 18, to assume a first stable clamping position, see fig. 2 or fig. 3.
In the clamping position, the stop lever 17 is engaged in one of the fastening elements 15a and the rotating components 23 abut against a first striker 24.
The stop lever 17 is also configured to assume a second stable unclamping position, see fig. 7b, in which it is disengaged from the fastening element 15a and the rotating components 23 abut against another striker 42.
In the first clamping position, the tooth 22 is inserted in one of the fastening elements 15a, while in the unclamping position the tooth 22 is disengaged from the fastening elements 15a.
The striker 24 is a substantially horizontal plane. The rotating components 23 are positioned on a fixed pin 44 of the stop lever 17. The stop lever 17 comprises, in an intermediate position, an elongated hole 25 by means of which it engages on the fixed pin 26. At the end 47 opposite to the one by means of which it engages in at least one of the fastening elements 15a, in particular by means of the tooth 22, the stop lever 17 comprises a pin 27 on which a first end 28 of a reset lever 29 is pivoted, in particular a rocking lever able to reset, that is, re-engage, the safety device 16. The first end 28 comprises a tooth 34 configured to abut against a striker 35, for example a rotation blocking pin provided in the stop lever 17.
The safety device 16 is substantially contained within a seating 38 made in the slider 13a and is kept in position by the pin 26 on which the stop lever 17 engages.
The reset lever 29 comprises a roller 31 configured to slide along the surface of the column 11a. At a second end 32, opposite to the first end 28, there is positioned a suitably shaped reset tooth 33, configured to abut against the surface of the column 11a. In particular, the reset tooth 33 can follow the profile of the column 11a in descent and in ascent.
Elastic means 36 are wound around the pin 27 of the reset lever 29, for example a torsion spring, able to keep the tooth 34 against the striker 35.
The ends of the elastic means 18 are wound around the pins 26 and 27, for example a traction spring.
The unclamping element 19 can comprise a cable, in particular a metal one, provided at the end with a terminal 39 secured between attachment pins 40 which are integral with the stop lever 17.
The unclamping element 19 can therefore be gripped by the user in order to take the stop lever 17 to the unclamping position.
The other striker 42 is made inside the slider 13a, which is configured to stop the stop lever 17 in the stable unclamping position. In the stable unclamping position, as mentioned, the rotating components 23 are in contact with the striker 42, see for example fig. 7b.
The stop lever 17, see in particular figs. 4, 5 and 6, can be formed by two preferably identical parts 17' and 17", or grips, between which the reset lever 29 is at least partly inserted. The two parts 17' and 17" are kept equidistant thanks to the presence of the pins 27, 40, of the striker 35 and of a possible spacer peg 41.
In addition to the reset lever 29, the elastic means 18, 36 and the rotating components 23 are also housed between the parts 17' and 17", so as to form a structurally stable sandwich structure. See in particular fig. 6, where two identical rotating components 23 are shown, configured to rotate around the pin 44.
The safety device 16 can also comprise a protection casing 43 associated with the slider 13a, see in particular fig. 5. The pin 26 of the stop lever 17 can protrude from the casing 43.
The traction action exerted by the elastic means 18 on the stop lever 17 through the pin 27 causes the rotating components 23 to be constantly thrust upward and kept in contact with the striker 24 or with the striker 42 in one of the two positions of stable equilibrium allowed by the traction of the elastic means 18, that is, with the stop lever 17 slightly rotated clockwise with respect to the vertical, as in fig. 2 or 3, or counterclockwise, as in fig. 7b. The transition between the two positions can only occur by causing a tensioning of the elastic means 18, which will be maximum when the stop lever 17 is perfectly vertical and with an axis orthogonal with respect to the striker 24, passing through a position of indifferent equilibrium, to then snap automatically and stably into the opposite side.
The limitation to the clockwise rotation of the stop lever 17 is guaranteed by the contact with the column 11a of the lifting system 10, or by the fastening elements 15a created thereon, while, in the counterclockwise rotation, it is the striker 42 that stops the rotation.
When the stop lever 17 is rotated toward the column 11a, the reset lever 29, under the action exerted by the elastic means 36, will be in complete extension, with the tooth 34 resting on the striker 35. In these conditions, the shaped end of the reset tooth 33 which faces toward the column 11a is a few millimeters away from the fastening elements 15a, see for example fig. 2 and fig. 3.
Conversely, when the stop lever 17 is rotated toward the striker 42, the reset lever 29, its reset tooth 33 coming into contact with the column 11a, will in turn rotate counterclockwise around the pin 27, overcoming the action of the elastic means 36, see fig. 7b.
The action of the elastic means 36 will always guarantee the contact between the shaped profile of the reset tooth 33 and the surface or the fastening elements 15a of the column 11a.
When the lifting system 10 has a load positioned for example on the support 14a of the slider 13 a in an elevated position, the stop lever 17 can engage, in particular by means of the tooth 22, in one of the fastening elements 15a. This engagement of the tooth 22 in the fastening element 15a occurs when the slider 13a is in the appropriate position, see for example figs. 2 and 3. The tooth 22 could also be in contact with the column 11a, see fig. 7i, or in an intermediate position, see fig. 7h.
In figs. 2 and 3, the reset lever 29, due to the action exerted by the elastic means 36 on its tooth 34, is rotated and resting on the striker 35.
A decision is made to drive the lifting system 10 in order to lower the load: before driving the drive means 12 electrically by means of a suitable control unit, the unclamping element 19, the terminal 39 of which is secured between the attachment pins 40 integral with the stop lever 17, is pulled manually. The action exerted on the unclamping element 19 causes the stop lever 17 to rotate anticlockwise, see figs. 7a and 7b.
The rotation of the stop lever 17 occurs with partial sliding downward thanks to the elongated hole 25, placing the elastic means 18 under tension, and it is facilitated by the rolling of the rotating components 23 on the striker 24. The stop lever 17 passes through the vertical position of indifferent equilibrium and subsequently automatically snaps into a position of stable equilibrium with the stop lever 17 resting on the striker 42, see fig. 7b. The lifting system 10 is thus unclamped and the slider 13a is free to begin the descent.
Simultaneously, the reset lever 29, dragged by the stop lever 17, as a first step rotates integrally with it, moving closer the surface of the column 11a. As soon as contact with the column 11a is reached, that is, when the reset tooth 33 is tangent to the surface or is partly inserted in one of the fastening elements 15a present, the reset lever 29 begins to rotate counterclockwise around its own pin 27 relative to the stop lever 17, overcoming the action of the elastic means 36 which, by reaction, tend to maintain the contact between the reset tooth 33 and the column 11a.
By starting the drive means 12, the slider 13a can now descend freely by sliding along its guides with the safety device 16 unclamped, see the sequence of drawings from 7a to 7c. The reset tooth 33, due to the tension of the elastic means 18, will remain adhering to the column 11a and its fastening elements 15a, following their profile along the entire descending travel, entering and exiting from the fastening elements 15a thanks to the rotation granted by its pin 27 and the recall of the elastic means 36.
The lifting system 10 can obviously be stopped in any intermediate position whatsoever along its descent whether one wishes, for example and in the case of several supports 14a, 14b, to unload only the lowest located support 14b, or whether one wishes to free all the objects located on the supports 14a, 14b, see for example fig. 7c or fig. 7d. In the stop position, the roller 31 can be inserted in one of the fastening elements 15a, see fig. 7c, or adhering to the surface of the column 11a, see fig. 7d.
If the drive means 12 are driven with the upward travel command, as in figs. 7e, 7f, 7g, the anti-fall safety device 16 automatically re-triggers, that is, it re-engages. The reset tooth 33 of the reset lever 29, rising upward, enters, thrust by the effect exerted by the elastic means 36, into the first useful fastening element 15a of the column 11a. At that point, it begins to freely rotate clockwise around its pin 27 as long as the striker 35 will allow it.
When the tooth 34 has reached the striker 35, as in fig. 7g, the relative rotation of the reset lever 29 with respect to the stop lever 17 is prevented, and therefore both levers will rotate integrally around the pin 26, also dragging the unclamping element 19 with them. Once the limit of the vertical position has been exceeded, the stop lever 17 snaps back into the fastening position, thanks to the action of the elastic means 18, resetting, or re-engaging, the safety device 16 in the clamping position.
From this moment, as shown in figs. 7h, 7i, 7j, the entire ascent phase will be carried out in complete safety: the stop lever 17, due to the tension of the elastic means 18, remains adhering to the column 11a and to its fastening elements 15a. Thanks to the curvilinear profile of at least part of the tooth 22 and to the presence of the rotating components 23, the stop lever 17 is able to follow the profile of the column 11a along the entire upward travel, entering and exiting from the fastening elements 15a. During this phase, the reset lever 29 oscillates dragged by the stop lever 17, at times resting on the column 11a or partly entering and exiting from the fastening elements 15a thrust by its elastic means 36.
Once a desired elevated position has been reached, it is possible to leave the lifting system 10 in this position with all its load, since in the event of an unfortunate slip or failure of the braking system mounted on the drive means 12 - for example an electric winch - due for example to wear of the brake disc or degradation of the elastic characteristics of the disc-compressing springs of the brake, collapse of the gear reducer or, worse, breakage of the lifting cable, the tooth 22 will fasten to the first fastening element 15a of the column 11a which it encounters along its descent, blocking its travel.
The reset lever 29 therefore substantially allows to take the stop lever 17 from the unclamping position shown for example in fig. 7b to the clamping position of fig. 2, fig. 3 or fig. 7j in an automatic manner, that is, without manually acting on the unclamping element 19 or on the stop lever 17. However, it would also be possible to provide an operation according to which the unclamping element 19 is kept pulled during the operations of descent of the slider 13a, and is released when the intention is to clamp the slider 13 a in position, causing the stop lever 17 to pass from the unclamping position to the clamping position.
Figs. 8a and 8b show the first embodiment of the column 11a which provides fastening elements 15a in the form of slits, grooves or suchlike along the surface.
Figs. 9a and 9b show a second embodiment of the column 11b in which, substantially, the fastening elements 15b provide slits, grooves or suchlike which have at their base a rest element 49 protruding from the surface of the column 11b.
Figs. 10a and 10b show a third embodiment of the column 11c in which the fastening elements 15c substantially define a sawtooth-shaped profile, where the various teeth have a quadrangular or similar section. These fastening elements 15c can therefore be part of a rack applied to the column 11c or be made on the surface of the column 11c.
Figs. 11a and 11b show a fourth embodiment of the column 11d in which the fastening elements 15d substantially define a sawtooth-shaped profile, where the various teeth have a hook-shaped, pointed or similar section. These fastening elements 15d can therefore be part of a rack applied to the column 11d or be made on the surface of the column 11d.
Figs. 12a and 12b show a fifth embodiment of the column 11e provided with fastening elements 15e. The column 11e has two flanks, or wings, orthogonal to the surface of the column 11e which has the fastening elements 15e.
It is evident that any one of the embodiments of the column 11a, 11b, 11c, 11d, 11e can be advantageously used in the present lifting system 10. Therefore, the operation of the lifting system 10a described with particular reference to the column 11a could also refer, in the same way, to the use of any other of the columns 11b, 11c, 11d, 11e. As mentioned in the disclosure of the invention, the elements 15a, 15b, 15c, 15d, 15e can be made on any surface of the column 11a, 11b, 11c, 11d, 11e, therefore front, lateral, rear or any combination thereof.
Preferably, the fastening elements 15a, 15b, 15c, 15d, 15e provided in the columns 11a, 11b, 11c, 11d, 11e are reciprocally equidistant.
Figs. 13a and 13b show a variant of the safety device 16a in which a pin 17a provided with elastic means 18a is used as a stop element, instead of the stop lever 17. The pin 17a is thrust by the elastic means 18a against the column's fastening elements, for example the fastening elements 15d of the column 11d.
Such pin 17a comprises, at the lower part, a surface 50 configured to abut against a striker 51 of the fastening elements 15d and, at the upper part, an inclined plane 52 configured to slide on an inclined plane 53 made on the fastening elements 15d. The surface 50 and the striker 51 are substantially horizontal.
The slider 13a is equipped on one side with a through hole 54 which allows the support and passage of the pin 17a, which is positioned inside the slider 13a.
In the clamping position of fig. 13a, the safety device 16a prevents the downward motion of the slider 13a, but allows its upward motion, thanks to the inclined planes 52, 53. During the upward motion, the pin 17a follows the profile of the fastening elements 15d and thanks to the action of the elastic means 18d it can stop in any position, with the surface 50 abutting against the striker 51 of one of the fastening elements 15d.
In the unclamping position of fig. 13b, in which the pin 17a is disengaged from the fastening elements 15d, the slider 13a can move upward and downward.
The pin 17a can for example move in a horizontal direction away from the column 11d thanks to the drive of the unclamping element 19a, which can be for example a cable associated with the end of the pin 17a opposite to the one with which it engages with the fastening elements 15d. The movement of the pin 17a away from the column 11d determines the passage from the clamping position of fig. 13a to the unclamping position of fig. 13b, against the action of the elastic means 18a which compress.
By releasing the unclamping element 19a, the pin 17a returns automatically and in a snap-in manner, thanks to the action of the elastic means 18a, back in the position of fig. 13a, in which the safety device 16a prevents the downward motion of the slider 13a.
Figs. 14a, 14b and 14c show another embodiment of the safety device 16, in which the stop lever 17 is configured as a "strut" instead of as a "hook". In this embodiment, the same reference numbers as the previous embodiments have been used to identify elements which are the same or have a similar or equivalent function.
The stop lever 17, also configured to snap-engage with, that is, fasten to, at least one of the fastening elements 15, is pivoted on a fixed pin 26 which is integral with the casing 43, and comprises an elongated hole 25 by means of which it can oscillate with respect to another fixed pin 57 which is integral with the casing 43 and engaged in the elongated hole 25. An elastic mean 18 is configured to keep the stop lever 17 under pressure toward the column 11 in a stable position.
The stop lever 17 comprises, at the end opposite to the one by means of which it engages in at least one of the fastening elements 15, an end 46 configured to engage on a mobile pin 42 which can be driven by a reset lever 29 which has the function of automatically resetting the safety device 16.
The mobile pin 42 is configured to oscillate inside a slot-shaped seating 56 made on the casing 43, being able to translate inside it between a stable position, secured by the tension of the elastic means 36, and a position in which the elastic means 36 are stretched.
The mobile pin 42 can oscillate inside the slot 56 thrust by the reset lever 29, which is in turn driven by the fastening elements 15.
The reset lever 29, rotatably associated with a fixed pin 58, comprises a first end 28, configured to engage with the mobile pin 42, a second end 32, opposite to the first end 28, configured to abut against the surface of the column 11 or be inserted in the fastening elements 15, and elastic means 55 configured to return the reset lever 29 to a "neutral" position between one oscillation and the other, when it is not dragged by the fastening elements 15.
An unclamping element 19 comprises a cable provided with a terminal 39 secured between attachment elements or pins which are integral with the stop lever 17.
By exerting a traction on the cable (fig. 14a), the stop lever 17 begins a rotation around its fixed pin 26 and its tooth 22 unfastens and moves away from the column 11. The reset lever 29 remains stationary.
The stop lever 17 continues its rotation and begins to thrust, with its end 46, the mobile pin 42 along the slot 56. The reset lever 29 still remains stationary.
As the end of the travel determined by the elongated hole 25 with respect to the fixed pin 57 approaches, the stop lever 17 thrusts the mobile pin 42 with its end 46 until it is able to go over it, then it stops abutting against the pin 58 of the reset lever. At this point, the mobile pin 42 snaps backward due to the action of the elastic means 36 and returns to the bottom of the slot 56 (fig. 14b). The stop lever 17 remains clamped in a stable position, unable to rotate backward because of the contact between the mobile pin 42 and its end 46, and the safety device 16 is unclamped. It is now possible to make the slider 13a move downward.
During the descent of the slider 13a, the reset lever 29 rotates freely, entering and exiting from the fastening elements 15 without driving anything, raising its end 32 and lowering its end 28, returning each time to the horizontal position thanks to its elastic means 55. This for every fastening element 15 intercepted. The stop lever 17 remains stationary in the unclamped position.
By driving the upward movement device, the slider 13a rises and the reset lever 29, dragged by the first useful fastening element 15 intercepted, rotates in the opposite sense, lowering its end 32 and raising its end 28. In this oscillatory movement, the end 28 raises the mobile pin 42 along the slot 56 until it frees the stop lever 17 which, due to the tension exerted by its elastic means 18, snaps rotating until the abutment on the fixed pin 24, thus resetting the safety device 16.
Continuing the ascent, the stop lever 17 enters and exits from the fastening elements 15 of the column 11 sliding on the roller 30, and at the same time the reset lever 29 oscillates driving the mobile pin 42 which slides freely along the slot 56, without however driving anything. Both return to the neutral position thanks to their respective elastic means 36 and 55.
It is clear that modifications and/or additions of parts may be made to the lifting system as described heretofore, without departing from the field and scope of the present invention, as defined by the claims.
It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of lifting system, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.
In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

Lifting system (10), comprising a single column (11a, 11b, 11c, 11d, 11e) along which at least two sliders (13a, 13b), overlapping with each other and reciprocally distanced, can slide by means of corresponding drive means (12), each slider (13a, 13b) being provided with a support (14a) for at least one load, wherein said column (11a, 11b, 11c, 11d, 11e) comprises fastening elements (15a, 15b, 15c, 15d, 15e) along its extension and said at least one slider (13a) comprises a safety device (16, 16a) provided with a stop element (17, 17a), configured to snap-engage with at least one of said fastening elements (15a, 15b, 15c, 15d, 15e) by means of elastic means (18, 18a) which tend to keep it under pressure toward said column (11a, 11b, 11c, 11d, 11e) in a stable position and therefore keep said at least one slider (13a) stationary at least in descent, said safety device (16, 16a) being provided with an unclamping element (19, 19a), associated with said stop element (17, 17a) and configured to overcome the force of said elastic means (18, 18a) and therefore free said stop element (17, 17a) from the fastening element with which it is engaged, so as to allow said sliders (13a) a downward motion along said column (11a, 11b, 11c, 11d, 11e), wherein the slider (13b) below is connected to said higher slider (13a) by means of connection elements (45).
Lifting system (10) as in claim 1, characterized in that only the higher located slider (13a) has the safety device (16, 16a), and said other sliders are attached to said higher slider by means of cables or belts.
Lifting system (10) as in claim 1 or 2, characterized in that said stop element comprises a stop lever (17) provided at one end (46, 47) with at least one tooth (22) configured to engage with at least one of said fastening elements (15a, 15b, 15c, 15d, 15e).
Lifting system (10) as in claim 3, characterized in that said stop lever (17) comprises one or several rotating components (23) and it is configured, thanks to a rotation around a pin (26) attached to the slider (13a) and to the action of said elastic means (18), to assume a first stable clamping position, that is, engaged with one of said fastening elements (15a, 15b, 15c, 15d, 15e) and with said rotating components (23) abutting against a first striker (24), and a second stable unclamping position, in which it is disengaged from said fastening elements (15a, 15b, 15c, 15d, 15e) and said rotating components (23) abut against another striker (42).
Lifting system (10) as in claim 4, characterized in that said stop lever (17) comprises an elongated hole (25) in which said pin (26) or another fixed pin (57) engages.
Lifting system (10) as in any claim from 3 to 5, characterized in that said stop lever (17), at the end (47, 46) opposite to the one by means of which it engages with one of said fastening elements (15a, 15b, 15c, 15d, 15e), comprises or cooperates with a pin (27, 58) on which there is pivoted a reset lever (29) which is configured to automatically reset said safety device (16).
Lifting system (10) as in claim 6, characterized in that said reset lever (29) comprises a first end (28) configured to engage with said pin (27), which is mobile, and provided with a tooth (34) configured to abut against a striker (35), a second end (32) opposite to said first end (28) in which there is positioned a reset tooth (33) configured to abut against the surface of the column (1 1a, 11b, 11c, 11d, 11e), and elastic means (36) wound around said pin (27) and configured to keep said tooth (34) against said striker (35).
Lifting system (10) as in any claim from 3 to 6, characterized in that the end (46) of said stop lever (17), opposite to the one by means of which it engages in at least one of said fastening elements (15a, 15b, 15c, 15d, 15e), is configured to engage on a mobile pin (42) which can oscillate in a slot-shaped seating (56).
Lifting system (10) as in claim 8, characterized in that said reset lever (29) is rotatably associated with said pin (58) which is fixed, wherein a first end (28) of said reset lever (29) is configured to engage with said mobile pin (42), while an opposite second end (32) of said reset lever (29) is configured to abut against said column (11a, 11b, 11c, 11d, 11e) or to engage with said fastening elements (15a, 15b, 15c, 15d, 15e), and wherein elastic means (55) are associated with said reset lever (29) in order to return it to a stable position between one oscillation and the other.
Lifting system (10) as in any claim from 3 to 9, characterized in that said unclamping element (19) comprises a cable provided with a terminal (39) secured between attachment pins or elements (40) which are integral with said stop lever (17).
Lifting system (10) as in any claim from 6 to 10, characterized in that said stop lever (17) is formed by two parts (17', 17") between which said reset lever (29) is at least partly inserted.
Lifting system (10) as in claim 1 or 2, characterized in that said stop element comprises a pin (17a) configured to snap-engage, by means of said elastic means (18a), with at least one of said fastening elements.
Lifting system (10) as in claim 12, characterized in that said pin (17a) comprises, at the lower part, a surface (50) configured to abut against a striker (51) of said fastening elements (15d) and, at the upper part, an inclined plane (52) configured to slide on an inclined plane (53) made on said fastening elements (15d).
Lifting system (10) as in any claim hereinbefore, characterized in that said safety device (16, 16a) comprises a protection casing (43) associated with said slider (13a).