HK1236175B - Braking system for a hoisted structure and method of controlling braking a hoisted structure - Google Patents

Description

Braking system for a raised structure and method for controlling braking of a raised structure

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Serial No. 62/233,370, filed September 27, 2015, which is incorporated herein by reference in its entirety.

Background Art

Embodiments herein relate to braking systems, and more particularly to controlling the braking of a raised structure.

Hoisting systems, such as elevator systems, often include a hoisted structure (e.g., an elevator car), a counterweight, and tension members (e.g., ropes, belts, cables, etc.) connecting the hoisted structure and the counterweight. During operation of such systems, a safety brake system is configured to help brake the hoisted structure relative to a guide member, such as a guide rail, if the hoisted structure exceeds a predetermined speed or acceleration.

Existing attempts to actuate a brake device typically require a mechanism that includes a governor, a governor rope, a tensioning device, and a safety actuation module. The safety actuation module comprises a lifting rod and a linkage mechanism for actuating a safety device, also known as a brake. Reducing, simplifying, or eliminating the components of this mechanism while providing reliable and stable braking of the lifted structure has proven advantageous.

In addition to the above-mentioned problems, existing safety brake assemblies are semi-passive systems that undesirably have difficulty providing control over the amount of braking force applied during a braking event.

Summary of the Invention

According to one embodiment, a braking system for a lifted structure guided along a guide rail is provided. The braking system includes a brake member for coupling to the lifted structure and having a braking surface configured to frictionally engage the guide rail, the brake member being movable between a braking position and a non-braking position. The system also includes a brake member actuation mechanism operably coupled to the brake member and configured to actuate the brake member from the non-braking position to the braking position. The brake member actuation mechanism remains coupled to the brake member in the braking position to control the braking force applied to the lifted structure by the frictional engagement between the guide rail and the brake member.

Additionally or alternatively to one or more of the above features, further embodiments may include the brake member actuation mechanism comprising a solenoid operably coupled to the brake member with a biasing member.

Additionally or alternatively to one or more of the above features, further embodiments may include the brake member being operably coupled to the brake member using a coupling spring.

Additionally or alternatively to one or more of the above features, further embodiments may include the brake member actuation mechanism being disposed in sliding contact with the guide rail.

In addition or alternatively to one or more of the above features, further embodiments may include the brake member actuation mechanism being biased into contact with the guide rail using a biasing spring.

Additionally or alternatively to one or more of the above features, further embodiments may include controlling deceleration of the raised structure based on control of the current provided to the solenoid.

Additionally or alternatively to one or more of the above features, further embodiments may include the brake member actuation mechanism comprising an electromechanical actuator operably coupled to the brake member with a release linkage.

Additionally or alternatively to one or more of the above features, further embodiments may include a coupling spring disposed between the brake member and a frame structure disposed proximate the electromechanical actuator.

Additionally or alternatively to one or more of the above features, further embodiments may include the electromechanical actuator being in operative communication with a speed monitoring device configured to detect an overspeed condition of the raised structure.

Additionally or alternatively to one or more of the above features, further embodiments may include the speed monitoring device comprising at least one of an optical sensor and an accelerometer, wherein the brake member actuation mechanism actuates the brake member upon detecting an overspeed condition.

In addition or alternatively to one or more of the above features, further embodiments may include a biasing spring surrounding at least a portion of the release linkage.

In addition to or alternatively to one or more of the above features, further embodiments may include: the braking member includes a movable wedge member disposed between the guide rail and the fixed wedge member, wherein the movable wedge member and the fixed wedge member each include angled surfaces that are disposed in close proximity to each other and oriented at complementary angles.

Additionally or alternatively to one or more of the above features, further embodiments may include that the angled surface of the movable wedge member comprises 20 degrees.

In addition to or as an alternative to one or more of the above features, further embodiments may include a plurality of wedge rollers disposed between the movable wedge member and the fixed wedge member.

According to another embodiment, a method for controlling braking of a lifted structure guided along a guide rail is provided. The method includes detecting an overspeed condition of the lifted structure. The method also includes actuating a brake wedge to engage the guide rail with a brake member actuation mechanism. The method further includes actively controlling a braking force generated by frictional engagement of the brake wedge and the guide rail by maintaining a coupling between the brake wedge and the brake member actuation mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded as the present disclosure is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the present disclosure will be apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG1 is a schematic diagram of an elevator system according to a first embodiment;

FIG2 is a schematic diagram of an elevator system according to a second embodiment;

FIG3 is a schematic diagram of a braking system for a lifted structure according to an aspect of the present disclosure; and

FIG4 is a schematic diagram of a braking system according to another aspect of the present disclosure.

DETAILED DESCRIPTION

With reference to the accompanying drawings, embodiments of a braking system for a hoisted structure are provided herein. In some embodiments, the hoisted structure is an elevator operating within an elevator system, but it should be appreciated that any type of hoisted structure can benefit from the embodiments disclosed herein. In the context of an elevator system, it should be understood that a variety of elevator systems are contemplated that can benefit from the braking system embodiments disclosed herein.

In some embodiments, an elevator system 10 includes tension members such as ropes, cables, etc., as shown in FIG1 . Elevator system 10 includes an elevator car 12 disposed within an elevator shaft 14 and capable of moving therein, typically vertically. A drive system 16 includes a motor and brakes and is conventionally used to control the vertical movement of elevator car 12 along elevator shaft 14 via a traction system including cables, belts, etc. 18 and at least one pulley.

Referring now to FIG. 2 , an elevator system 10 may alternatively be referred to as a "ropeless" elevator system. FIG. 2 depicts a multi-car ropeless elevator system according to an exemplary embodiment. Elevator system 10 includes a hoistway 20 having multiple passageways 13, 15, and 17. In one embodiment, elevator system 10 comprises modular components that can be connected to form an elevator system. Modular components include, but are not limited to, landing hoistways, shuttle platform hoistways, transfer stations, carriages, parking areas, disengagement mechanisms, and the like. While FIG. 2 shows three passageways, it should be understood that the embodiment can be applied to a multi-car ropeless elevator system having any number of passageways. In each passageway 13, 15, and 17, elevator cars 12 mostly travel in one direction (i.e., up or down). For example, in FIG. 2 , cars 12 in passageways 13 and 17 travel upward, while car 12 in passageway 15 travels downward. One or more cars 12 may travel in a single passageway 13, 15, and 17. In one embodiment, the car 12 can move bidirectionally within the aisles 13, 15, 17. In one embodiment, the aisles 13, 15, 17 can support a shuttle function during certain times of the day (e.g., rush hour) to allow for unidirectional, selective stopping, or switchable directionality as needed. In one embodiment, the aisles 13, 15, 17 can include localized directionality, where certain areas of the aisles 13, 15, 17 and hoistway 20 are allocated to various functions and building components. In one embodiment, the car 12 can circulate within a restricted area of the hoistway 20. In one embodiment, the car 12 can operate at a reduced speed to reduce operating and equipment costs. In other embodiments, the hoistway 20 and aisles 13, 15, 17 can operate in a mixed operating mode, where portions of the hoistway 20 and aisles 13, 15, 17 operate normally (unidirectional or bidirectional), while other portions operate in another mode, including but not limited to unidirectional, bidirectional, or in a parking mode. In one embodiment, when an aisle is designated for parking, a parked car can be parked in the aisle 13, 15, 17.

3, regardless of the particular type of elevator system with which it is used, the brake system is configured to controllably apply a braking force to decelerate, stop, and hold the elevator car 12 relative to the guide members. The brake system is generally indicated by numeral 30 and is described in detail herein.

According to the embodiment shown in FIG3 , a first embodiment of a braking system 30 is shown. The guide members that guide the elevator car 12 are referred to herein as guide rails 32 and are connected to structural features of the elevator system 10, such as the walls of the elevator car passage, and are configured to guide the lift structure, typically in a vertical manner. The guide rails 32 can be formed from a variety of suitable materials, typically a durable metal such as steel.

The braking system 30 includes a brake member 34 having a contact surface 35 operable to frictionally engage the guide rail 32. The brake member 34 is movable between a non-braking position and a braking position. The non-braking position is the position to which the brake member 34 is disposed during normal operation of the lifted structure. Specifically, when the brake member 34 is in the non-braking position, the brake member 34 is not in contact with the guide rail 32 and, therefore, is not frictionally engaged with the guide rail 32.

Braking system 30 includes a stationary member 36 mounted to a frame 38 of elevator car 12. Stationary member 36 allows brake member 34 to translate relative to it. Following translation of brake member 34, brake member 34 contacts guide rail 32, thereby frictionally engaging guide rail 32. Stationary member 36 includes tapered walls 40, and brake member 34 is formed into a wedge-like configuration that forces brake member 34 into contact with guide rail 32 during movement from the unbraking position to the braking position. The wedge-like configuration of brake member 34 includes tapered walls 42 that substantially correspond to tapered walls 40 of stationary member 36. Tapered walls 40, 42 are oriented at an angle that facilitates sufficient mechanical advantage for the wedging force but does not allow binding or binding of brake system 30. In one example, the angle is approximately 20 degrees relative to vertical. One or more components 44 may be disposed between tapered walls 40, 42 to facilitate sliding of brake member 34. In the illustrated embodiment, the one or more components are rollers, but it will be appreciated that alternative configurations may be employed.

In the braking position, the friction between the contact surface 35 of the brake member 34 and the guide rail 32 is sufficient to stop the movement of the lifted structure relative to the guide rail 32. Although a single brake member is shown and described herein, it should be appreciated that more than one brake member may be included. For example, a second brake member may be positioned on an opposite side of the guide rail 32 relative to one side of the brake member 34, such that the brake members work in conjunction to achieve braking of the lifted structure.

The brake system 30 also includes a brake member actuation mechanism 50. The brake member actuation mechanism 50 is selectively operable to actuate movement of the brake member 34 from the non-braking position to the braking position. More specifically, the brake member actuation mechanism 50 applies a relatively low force to initiate movement of the brake member 34, yet also sufficiently controls the braking and/or holding force generated by the frictional engagement between the guide rail 32 and the brake member 34. To facilitate this control by the brake member actuation mechanism 50, the mechanism 50 remains in contact with (e.g., coupled to) the brake member 34 even after actuation of the brake member 34 (i.e., when the brake member is in the braking position).

In the illustrated embodiment, the brake member actuation mechanism 50 includes an electromechanical actuator 52 operably coupled to the frame 38 of the elevator car 12. A coupling device 54 is operably coupled to the electromechanical actuator 52 and extends toward and contacts the brake member 34. Upon activation by the electromechanical actuator 52, the coupling device 54 exerts a force on the brake member 34. The coupling device 54 remains coupled to the brake member 34 at all times and is configured to release the brake member 34 from frictional contact by exerting a force on the brake member 34, which pulls the brake member downward to allow for a simple and quick transition from a braking position to an unbraking position. This process reduces or eliminates the need to mechanically lift the elevator car 12 to release the brake member 34. In some embodiments, a spring 56 operably coupled to the brake member 34 at one end and to the frame 38 at the other end is included to facilitate this effort.

In operation, electronic sensors and/or a control system (not shown) are configured to monitor various parameters and conditions of the lifted structure and compare the monitored parameters and conditions to at least one predetermined condition. In one embodiment, the predetermined condition includes the speed and/or acceleration of the lifted structure. If the monitored condition (e.g., overspeed, overacceleration, etc.) exceeds the predetermined condition, the brake member actuation mechanism 50 is actuated to cause the brake actuator 34 to move into engagement with the guide rail 32. The device used to detect the monitored condition can vary. For example, the device can be an optical sensor or an accelerometer.

4 , another embodiment of a brake member actuation mechanism is shown and generally designated by the numeral 60. The brake member actuation mechanism 60 includes a solenoid 62 disposed proximate to the guide rail 32. In some embodiments, the solenoid 62 is disposed in sliding contact with the guide rail 32. To maintain contact between the solenoid 62 and the guide rail 32, a biasing spring 68 is operatively coupled to the solenoid 62 at one end and to the frame 38 of the elevator car 12 at the other end.

The solenoid 62 is operably coupled to the brake member 34 using a coupling member 64, such as a coupling spring configured for compression or tension. As the solenoid 62 slides along the guide rail 32, a resistance force is generated and an actuation force is provided, which is controlled by the current supplied to the solenoid 62. After a predetermined force is reached, the brake member 34 is actuated and moved to the braking position. The current supplied to the solenoid 62 controls the deceleration and holding force of the elevator car 12.

In addition to the above embodiments, the brakes may be actuated using, for example, pneumatic, hydraulic, and pyrotechnic means.

The embodiments described herein advantageously provide a braking system 30 that actuates the braking member 34 and controls the applied braking force. By fully controlling the braking force, the integration of the safety and holding brakes reduces cost and weight and increases the simplicity of the overall system.

Although the present disclosure has been described in detail in conjunction with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to the embodiments so disclosed. Rather, the present disclosure can be modified to include any number of variations, alterations, substitutions, or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the present disclosure. Additionally, although various embodiments of the present disclosure have been described, it should be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure should not be construed as limited by the foregoing description, but is limited only by the scope of the appended claims.

Claims (9)

1. A braking system for a lifting structure guided along a guide rail, the braking system comprising: A braking member for coupling to the lifting structure and having a braking surface configured to frictionally engage the guide rail, the braking member being movable between a braking position and a non-braking position; and A brake member actuation mechanism, operably coupled to the brake member and configured to actuate the brake member from the non-braking position to the braking position, the brake member actuation mechanism being configured to retain the brake member coupled to the braking position in order to control the braking force applied to the lifting structure by the frictional engagement between the guide rail and the brake member; Its features are: The braking member actuation mechanism includes an electromechanical actuator operably coupled to the braking member having a connecting device operable to release the braking member from the braking position to the non-braking position. 2. The braking system according to claim 1, further comprising a connecting spring disposed between the braking member and a frame structure disposed near the electromechanical actuator. 3. The braking system according to claim 1 or 2, wherein the electromechanical actuator is operatively in communication with a speed monitoring device configured to detect overspeed conditions of the lifting structure. 4. The braking system of claim 3, wherein the speed monitoring device comprises at least one of an optical sensor and an accelerometer, wherein the braking member actuation mechanism actuates the braking member when the overspeed condition is detected. 5. The braking system according to claim 1 or 2, further comprising a biasing spring surrounding at least a portion of the release coupling. 6. The braking system according to claim 1 or 2, wherein the braking member includes a movable wedge member disposed between the guide rail and the fixed wedge member, wherein the movable wedge member and the fixed wedge member each include an angled surface, the angled surfaces being arranged close to each other and oriented at complementary angles. 7. The braking system of claim 6, wherein the angled surface of the movable wedge member comprises 20 degrees. 8. The braking system of claim 6, further comprising a plurality of wedge rollers disposed between the movable wedge member and the fixed wedge member. 9. A method for controlling the braking of a hoisting structure guided along a guide rail, the method comprising: Detect the overspeed condition of the lifting structure; The brake wedge is actuated by a braking component actuation mechanism to engage the guide rail; and The braking force generated by the frictional engagement of the brake wedge and the guide rail is actively controlled by maintaining the connection between the brake wedge and the brake member actuation mechanism; Its features are: The braking member actuation mechanism includes an electromechanical actuator operably coupled to the braking member having a connecting device operable to release the braking member from a braking position to a non-braking position.