WO2005040025A1

WO2005040025A1 - Elevator rescue drive mechanism

Info

Publication number: WO2005040025A1
Application number: PCT/EP2003/011091
Authority: WO
Inventors: Helmut Lothar Schroeder-Brumloop
Original assignee: Otis Elevator Company
Priority date: 2003-10-07
Filing date: 2003-10-07
Publication date: 2005-05-06
Also published as: AU2003273956A1

Abstract

Elevator rescue drive (2) for an elevator comprising a car (4), a counterweight, guide rails (6) and a drive machine unit, characterised by a friction roller (18) adapted for frictional engagement with one of the guide rails (6); a support mechanism (16) which is mounted either to the car (4) or to the counterweight for rotatably supporting the friction roller (18); and a motor (22) for rotating the friction roller (18); wherein the support mechanism (16) comprises a biasing means (26) for biasing the friction roller (18) in use against the guide rail (6), a locking means (34) for locking the friction roller (18) in a disengaged position during normal operation of the elevator and an unlocking device (41) for bringing the friction roller (18) in engagement with the guide rail (6) in a rescue situation.

Description

ELEVATOR RESCUE DRIVE MECHANISM

The present invention relates to an elevator rescue drive for an elevator system comprising a car, a counterweight, guide rails and a drive machine unit, for moving the elevator car to a landing in case of a power failure, etc.

In case of failure of the drive machine unit of the elevator, for example due to a power failure, passengers are frequently trapped in the elevator car. There generally exists the need to evacuate the passengers from the elevator car within a relatively short time. Typically, a service technician or any other qualified staff of the building operator releases the brake which fell in immediately after the failure occurred. If the car and counterweight are in an unbalanced condition, after release of the safety brake the car either starts moving upwards or downwards. The service technician controls such move of the car and stops the car by triggering the brake again, once the car has reached the next landing. At the landing the door can be opened and the passengers can leave the car. In case of a balanced condition between the car and counterweight, however, the car does not start moving even if the brake is released, but will stay at its position due to the balanced load situation. As the elevator system is designed so that it is in a balanced load situation for the most common operational conditions, such a balanced load situation is not uncommon.

One approach to solve this problem is that the service technician manually turns a hand wheel or the traction sheave of the drive machine unit e.g. in case when a machine room is present and when the controls for releasing the safety brakes are near the drive machine unit. In other cases, e.g. if the controls for the safety brake are remote from the drive machine unit or if the drive machine unit is not easily accessible, i.e. in case of a machine roomless elevator system, this is no viable way. Another approach which has been suggested relies on a Bowden cable for transmitting the service technician's manual motive force to the drive machine unit in order to move the elevator car. Other approaches rely on an accumulator power backup system. For example US-A-5,821,476 discloses a switch device for rotating an elevator motor during an emergency situation comprising an accumulator and a rotary switch for supplying the DC voltage of the accumulator into the windings of the elevator motor in order to advance the elevator motor step by step. EP 0 733 577 A2 on the other hand suggests to provide a disc type drive machine unit with a rescue drive motor. The rescue drive motor is of the starting motor type as used for starting automotive internal combustion engines. In order to implement this approach, it is necessary to substantially amend the drive machine unit, e.g. by providing a gear rim on the periphery of the rotor and a bracket for securing the rescue drive. This and the additional solenoid necessary for bringing the pinion of the rescue drive motor correctly in engagement with the gear rim of the drive machine unit in case of activation adds substantial to the costs of the elevator system.

Thus, it is the object of the present invention to provide an elevator rescue drive for an elevator system comprising a car, a counterweight, guide rails and a drive machine unit, which is simple, reliable, cost- efficient and which can be retro-fitted in existing elevator installations with ease.

According to the present invention, this problem is solved by an elevator rescue drive comprising:

a friction roller adapted for a frictional engagement with one of the guide rails;

a support mechanism which is mounted to either of the car and counterweight for rotatably supporting the friction roller; and

a motor for rotating the friction roller; wherein the support mechanism comprises a biasing means for biasing the friction roller in use against the guide rail, a locking means for locking the friction roller in a disengaged position during normal operation of the elevator and an unlocking device for bringing the friction roller in engagement with the guide rail in a rescue situation.

The invention has the distinct advantage that the friction roller engages the guide rail of an elevator system which is already suited for cooperation with such friction roller due to the fact that it is manufactured for cooperation either with guiding rollers or guiding shoes. As, on the other hand, the elevator rescue drive is supported by the car or the counterweight, there is also no need to substantially amend these elements due to the fact that there are typically ample of possibilities for securing the elevator rescue drive thereto. Moreover, the car and/or counterweight typically provide sufficient space for accomo- dating the elevator rescue drive.

Generally it is preferred to mount the elevator rescue drive with the car, as the car is already connected by way of a connecting cable with the elevator control, etc. It is most preferred to place the elevator rescue drive at the top of the elevator car because normally there is sufficient space and because there it is easily accessible for inspection.

The friction roller may either be a separate wheel or part of the guiding arrangement, i.e. one or more guide rollers can be designed so as to act as friction rollers in an emergency situation. In this latter case the motor for rotating the friction roller may be designed so as to be engaged with or disengaged from the friction roller/guide roller.

Preferably, the support mechanism comprises a pressure roller which is positioned so as to act in use against the surface of the guide rail opposite to its surface, on which the friction roller acts. This construction allows for centering the guide rail between the friction roller and the pressure roller. Such centering avoids additions frictional resistance which may occur if the friction roller presses the guide rails against the respective guide shoes and guide rollers, respectively. The centering further ensures and maintains a predetermined pressure force of the friction roller against the guide rail.

Preferably, the support mechanism comprises two legs each of which being pivotally attached at one end thereof and having the friction roller and the pressure roller, respectively, attached to free ends thereof, and wherein the biasing means is connected with each of the legs. Preferably, the pivot points and the legs are substantially arranged symmetrically with respect to the guide rail which the friction roller acts upon. Moreover, preferably there is a base plate for securing the elevator rescue drive to the car or counterweight.

Preferably, the biasing means comprises a spring. Alternatively, the biasing means may comprise other actuators for forcing the friction roller and/or the pressure roller against the guide rail. Preferably, the spring is a tension spring.

Preferably, the unlocking device comprises a magnetic actuator or a solenoid. It is possible that the solenoid is also the locking device and is connected with the main power supply. In normal operation the solenoid is activated by the main power supply and locks the friction roller during normal operation of the elevator in a disengaged position. In case of a main power failure the solenoid is no longer energised, releases the friction roller and the biasing means bias the friction roller against the guide rail. Alternatively, the solenoid is not energised by the main power but by the auxiliary power supply, only, and is activated only in case of failure so as to unlock the locking device and to bring the friction roller in engagement with the guide rail.

Preferably, the support mechanism comprises a base portion to which the unlocking device is attached. This allows for a modular construction of the elevator rescue drive and simplifies attachment thereof to the car and/or counterweight.

Preferably, the locking means comprises two levers pivotally connected to each other and forming a toggle joint. The toggle joint is arranged so that it holds the friction roller away from the guide rail against the force of the biasing means in its extended resting position and allows engagement of the friction roller with the guide rail in its folded or bent position. The unlocking device may be connected to the toggle joint so as to move the toggle joint from the extended resting portion into the folding portion.

Preferably, the motor is an electrical motor and particularly a motor having a reduction gearing attached thereto or integrated therewith. Alternatively, a pneumatic or any other type of motor can be used.

Particularly, with an electrical motor, the reduction gear allows the use of a relatively small inexpensive motor.

Preferably, the motor is attached to the leg of the supporting mechanism supporting the friction roller. The motor may even form a structural part of such leg. This allows for a very compact elevator rescue drive.

The present invention also relates to an elevator comprising an elevator rescue drive in accordance with the present invention. The elevator rescue drive is preferably connected with a rescue control, e.g. a rescue control panel including control means, i.e. buttons, etc., for engaging or disengaging the brake and for activating the elevator rescue drive. The emergency control can also be automated, i.e. it may be controlled by a microprocessor so that it automatically conducts a rescue sequence after activation or automatically starts after a power failure has been detected a rescue sequence for bringing the car to the - preferably next - landing. For automated implementation it is preferred to connect the control with the governor or any other device providing information on the moving status of the elevator car and other device informing of the precise position of the elevator car relative to a landing. The invention and embodiments of the invention are described in greater detail below with reference to the Figures, wherein:

Fig. 1 shows an elevator rescue drive in accordance with the present invention; and

Fig. 2 shows an alternative embodiment of the elevator rescue drive of the present invention.

Figs 1 and 2 show part of an elevator system comprising an elevator rescue drive 2 which is mounted to an elevator car 4, a counterweight (not shown), guide rails 6 and a drive machine unit (not shown).

The elevator rescue drive comprises a base member 8 including a bracket 10 for pivotally mounting two legs 12 and 14 of a support mechanism 16 for a friction roller 18. The friction roller 18 is adapted for frictional engagement with guide rail 6 and particularly with the flange 20 of such guide rail 6. The flange 20 of the guide rail is manufactured so as to be in contact with either guiding shoes or guiding rollers (not shown) of the elevator car or counterweight. In order to enhance the frictional engagement between the friction roller 18 and the flange 20, it is possible to provide the friction roller 18 with a friction surface coating layer made of a friction enhancing material, i.e. rubber, etc., or it may even be completely made of such material. Wear is no matter of specific consideration, since the elevator will typically be in service very rarely.

As mentioned above, the electric motor 22 can be any type of conventional electric motor. Any mass product electric motors like automotive windshield - wiper motors or similar products are preferred. Most preferred are electric motors operating at low voltage.

The friction roller 18 is rotatably driven and supported by an electrical motor 22 via a reduction gearing 24. The electrical motor 22 and gearing 24 may form an integral part of the leg 14 or may alternatively be attached to leg 14. A biasing means 26 in the form of a tension spring 28 (Fig. 1) is attached to the friction roller 18 in order to bias the same against the flange 20 in use. Attached to the free end 30 of leg 12 is a pressure roller 32 for pressing in use against the opposite side of the flange 20 with respect to the contact side by friction roller 18. Thus the friction roller 18 and pressure roller 32 serve to center the flange 20 there between and avoid increased resistance between the elevator car guide means, i.e. guide roller or guide shoes, and the guide rails 6.

A locking means 34 is provided for locking the elevator rescue drive 2 and the friction and counter roller 18 and 32, respectively in a disengaged position during normal operation of the elevator. The locking means 34 comprises two levers 36, 38 which are pivotally connected to each other and with the legs 12 and 14, respectively. An armature 40 of a solenoid 42 is also connected with the levers 36 and 38 to keep the rollers 18 and 32 disengaged from flange 20 or to bring them out of engagement.

The lever 36, 38 may form a toggle joint similar to a human knee joint which allows flexion substantially only in one direction. Such a toggle joint has a substantially stable position in an expanded resting state so as to hold the legs 12 and 14 and rollers 18 and 32, respectively, in a position away from the flange 20 against the biasing force of the tension spring 28. With such a construction the toggle joint itself forms the locking means while the solenoid 42 forms the unlocking device. In an alternative embodiment the two levers 36, 38 do not form a toggle joint but are held down by the solenoid 42 which after de- energising allows the armature 40 and the levers 36, 38 to be moved upwards by the force of the tension spring 28. After use the elevator rescue drive 2 is either automatically reset in its disengaged position or has to be reset manually.

The motor 22 is powered by a control system which first initiates to release the brake after a failure. If no movement due to gravity results, the control system opens the brake again and powers the motor 22 to move the car 4 in a desired direction.

Fig. 2 shows an elevator rescue drive 2 having a different support mechanism 16. Such support mechanism 16 having a biasing means 26 in the form of a spindle drive. The spindle drive includes a drive motor 42 driving a screw 54 for displacing a nut 56. Attached to nut 56 is a lever mechanism 60 for engaging and disengaging friction roller 18 and pressure roller 32 with the guide rail flange 20. Particularly, the lever mechanism 60 comprises two levers 62 which are pivotally attached to nut 56 as well as to the legs or levers 14 and 16, respectively, via pivots 50. The legs 14, 16 in turn are pivotally attached to support structure 58 by way of pivots 52.

This type of bias mechanism 26 may integrally form the locking mechanism 34 for securely locking the rollers 18 and 32 in the disengaged position. Once actuated, the drive motor 42 rotates screw 54 resulting in a displacement of nut 56. The displacement of nut 56 in turn rotates legs 14 and 16 about pivots 52 for bringing rollers 18 and 32 in engagement with guide rail flange 20. In order to enhance the flexibility and in order to ensure a reliable bias force, an additional biasing element (not shown) can be provided with the lever mechanism 16 and the friction roller 18 and/or the pressure roller 32. One might also contemplate to omit pressure roller 32 in order to simplify the system.

A possible sequence of operation of the control system which may be started either automatically or by a person pressing a press button, can be as follows: In a first step, the sequence will open the machine brake, whereupon the control system determines whether the car moves according to gravity or not. If the car moves according to gravity, the control system will keep the brake open until the car reaches the next landing where it will stop the car and open the door. If the car does not move according to gravity, the control system will close the brakes again. This first step may be repeated several times, e.g. three times, if the car does not move. In a second step the control system energises the elevator rescue drive 2 and opens the brake at about the same time. If the car moves, the control system will keep the car moving until reaching the next landing where it will stop the elevator car 4 and open the door to allow the passengers to leave the elevator car. If the car does not move, the control system may stop the elevator rescue drive and close the brake and may re-try to move the car by energising the elevator rescue drive and opening the brake several times. If after such sequence the car has still not been moved to a landing, a service technician or any αthsr qualified personnel will have to take care for releasing the passengers from the car 4.

It is to be noted that according to the present invention the elevator rescue drive 2 can be implemented with virtually any existing elevator system of the traction type having car and counterweight The system can eas^'fiy be retrofitted into existing systems, ft is also possible to combine it with the electrical elevator brake release rescue system according to US 6,196,355 B1 or any s^'i ^' ar system.

Claims

1. Elevator rescue drive (2) for an elevator comprising a car (4), a counterweight, guide rails (6) and a drive machine unit, characterised by a friction roller (18) adapted for frictional engagement with one of the guide rails (6); a support mechanism (16) which is mounted either to the car (4) or to the counterweight for rotatably supporting the friction roller (18); and a motor (22) for rotating the friction roller (18); wherein the support mechanism (16) comprises a biasing means (26) for biasing the friction roller (18) in use against the guide rail (6), a locking means (34) for locking the friction roller (18) in a disengaged position during normal operation of the elevator and an unlocking device (41) for bringing the friction roller (18) in engagement with the guide rail (6) in a rescue situation.

2. Elevator rescue drive (2) according to claim 1, wherein the support mechanism (16) comprises a pressure roller (32) which is positioned so as to act in use against the surface of the guide rail (6) opposite to the surface thereof on which the friction roller (18) acts.

3. Elevator rescue drive (12) according to claim 2, wherein the support mechanism (16) comprises two legs (12, 14) each being pivotally attached at one end thereof and having the friction roller (18) and the pressure roller (32), respectively, attached to free ends thereof, and wherein the biasing means (26) is connected with each of the legs (12, 14).

4. Elevator rescue drive (2) according to any one of claims 1 to 3, wherein the biasing means (26) comprises a spring (28).

5. Elevator rescue drive (2) according to any one of claims 1 to 4, wherein the unlocking device (41) comprises a solenoid (42).

6. Elevator rescue drive (2) according to any one of claims 1 to 5, wherein the support mechanism (16) comprises a base portion (8) to which the unlocking device (41) is attached.

7. Elevator rescue drive (2) according to any one of claims 1 to 6, wherein the locking means (34) comprises two levers (36, 38) pivotally connected to each other and forming a toggle joint.

8. Elevator rescue drive (2) according to any one of claims 1 to 7, wherein the motor (22) is an electrical motor and has a reduction gear (24) attached thereto.

9. Elevator rescue drive (2) according to any one of claims 3 to 8, wherein the motor (22) is attached to the leg (14) of the support mechanism (16) supporting the friction roller (18).

10. Elevator (2) comprising an elevator rescue drive in accordance with any one of claims 1 to 9.