GB2206331A - Elevator car door locking mechanism - Google Patents

Abstract

In order to prevent the car doors of an elevator from being opened between floors in the event of a power failure, a locking mechanism is provided including a locking member 6 movable between a first position in which the doors 1,2 are locked and a second position in which the doors may be opened. The locking member is moved between these positions by means of an operating element 12 which co-operates with a cam member 15 provided at or adjacent each floor. In normal use the operating element 12 may be electromagnetically retracted and only co-operates with the cam member 15 in the event of a power failure. <IMAGE>

Description

"Elevator Car Door Locking Mechanism" This invention relates to a locking mechanism for an elevator car door or doors.

A safety requirement for elevators is that the car doors should resist being opened at all times when the car is not stationary at, or at least very close to, a floor.

Conventionally the doors of an elevator car are held closed during travel by means of an electromagnetic means such as by maintaining the power supply to the door motor to urge the doors closed.

It has also been proposed to provide an electromagnetic lock actuated by means of a solenoid that only allows the car doors to be opened when the car is stationary at a floor. Renown proposals have the disadvantage however that in the event of a power failure the solenoid lock is inoperable.

Thus if there is a power failure when the elevator car is between floors, the car doors can be opened, at least partly. Thus, known forms of locking means for the doors are vulnerable to being disabled in the event of a power failure, which is precisely when the occupants are most likely to try to force the doors open between floors and accordingly when it is desirable for the doors to be firmly locked; this can be particularly dangerous in the event of the elevator restarting after a power cut.

Viewed from a broad aspect the present invention provides a locking mechanism for the door(s) of an elevator car, comprising a locking member arranged to move to a first position wherein the door(s) is/are firmly locked when the car is between floors of a building at least in the event of failure of the power supply to the elevator, such member being mechanically coupled to an operating element arranged to co-operate with a cam member associated with the elevator shaft adjacent each floor in such a way that the locking member is held in a second position when the car is at or adjacent a floor wherein the door(s) may be opened.

In the event of a power failure occuring when the elevator is between floors, the doors are thus locked by means of the locking member.

The elevator may then be wound manually to the nearest floor by a rescue team, whereupon the doors are automatically released owing to the operating element engaging a respective cam. If power failure occurs with the car at a floor, the locking member will of course be retained in the unlocked position.

Such a locking mechanism may be provided in addition to a standard door locking means, although in preferred embodiments, as discussed below, the mechanism also operates to lock the door(s) between floors during normal operation of the car in which case an additional locking means may be omitted.

It is important that the locking member is moved to said first position by non-electrical means, or at least by a means whereby the first position is adopted in the event of a power failure.

In a preferred embodiment the locking member may be gravity or spring biased into the locked position and the operating element is adapted to move the locking member against the biasing force when the car is at a floor.

In a simple arrangement, the operating element may engage the cam members during normal operation of the elevator whenever the car stops at or passes a floor and on each occasion the locking member will be moved between the first and second positions.

This however has a disadvantage in that the repeated striking of the operating element on the cam members during travel of the car will cause considerable noise and also substantial wear and tear on the components.

Accordingly it is preferred that there is provided an actuator that is adapted to retain the operating element in a retracted position in which it does not engage the cam members at least when the car passes a floor during normal operation of the elevator, such an actuator being disabled in the event of a power failure. Preferably the actuator is electromagnetically operated, e.g.

a solenoid or motor.

Preferably the retracted condition of the operating element corresponds to a third position of the locking member in which the door(s) are also locked, the actuator being responsive to control means for the elevator so as to release the locking member and operating element when the car is stationary at or adjacent a floor in response to a car or landing call for such floor, so that the locking member moves to its second condition with the operating element engaging the respective cam so that the doors may be opened.With such an embodiment there is the additional advantage that, whilst the operating element does not engage the cam members during normal operation when the car passes a floor without stopping, the locking mechanism is none the less effective to firmly lock the doors at all times between floors, and also to maintain the doors locked as the car passes a floor without stopping, when the elevator operates normally.

Where the elevator stops in response to a car or landing call, the actuator releases the locking member and operating element so that the locking member moves to its second position, consequent upon engagement of the operating element with the respective cam member. In the event of a power failure occuring when the car is between floors, however, the consequential release of the locking member and operating element results in the member moving to its first position, wherein the door(s) remain locked, there being no adjacent cam member for the operating element to engage.

The car may then be wound manually (as is usual in the case of a prolonged power cut) to the nearest floor, whereupon the doors are automatically released by the operating element engaging the respective cam member.

Preferably the locking member comprises a pivotable bar having a notch at each end engageable with a respective pin associated with said door (s) wherein said first and third positions correspond to a position in which respective notches engage a pin, and said second position corresponds to a position in which neither notch engages a pin.

If the elevator car has only a single sliding door, the pins will be associated with that door.

If however the car has a pair of sliding doors, both pins may be associated with one door, or one pin may be associated with each door.

Preferably the operating element comprises a roller mounted on one end of a roller arm, the other end of said roller arm being connected to said locking member by means of rigid link.

While reference has been made to the elevator car being "at a floor" for the doors to be opened, it will be appreciated that the elevator car need not be exactly level with the floor, merely that the car is within a few inches of being level.

Viewed from a further aspect the invention provides an elevator car incorporating a locking mechanism as aforesaid.

Viewed from a still further aspect the invention provides an elevator system including at least one elevator car having a locking mechanism as aforesaid.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawing which is a schematic elevation of a door locking mechanism.

Referring to the drawing, there is shown schematically a locking mechanism applied to an elevator car having two door hangers 1, 2 arranged for centre opening of the doors. Fitted on each door is a respective pin 3, 4 mounted on a bracket 5.

Adjacent the pins 3, 4 is provided a locking member 6 pivotally mounted on a support bracket 7. The locking member is in the form of an elongate bar having a notch 8, 9 at either end, each notch being associated with one of the pins 3, 4. The inner corners of each notch are radiussed so as to provide a close fit with its associated pin.

The sidewalls of the notches at the point of entry are normal to the lower edge of the locking member and are tangential to its axis of rotation. Furthermore each pin is eccentrically mounted on the pin support bracket 5 so that the position of the pin can be finely adjusted. The very close fit of the notches and pins means that when the doors are locked, they are locked very tightly with little or no movement being possible.

The locking member 6 is pivotable about pivot point A in such a manner that when the locking member is pivoted in a clockwise direction (as viewed in the drawing) notch 9 engages pin 4.

When the locking member 6 is pivoted in a counterclockwise direction (as viewed in the drawing) notch 8 engages pin 3. The dimensions of the notches and pins, and the fine adjustement of the position of the pins, are selected to give a very close fit between the notches and pins.

It will be seen that the locking member 6 has three principal positions; a first position in which notch 8 engages pin 3, a second position (shown in the drawing) in which both notches clear the pins by a distance i, and a third position in which notch 9 engages pin 4.

The two doors, not shown, are suspended from the door hangers 1, 2 and may have a conventional electromagnetic locking means (also not shown).

Furthermore the two doors are inter linked in such a way that one door cannot be opened without the other.

The pivotal movement of the locking member 6 is controlled through two rigid link members 10, 11. x first rigid link 10 connects the locking member 6 to an operating element 12 in the form of a roller 13 mounted on one end of an arm 14.

The roller 13 is adapted to engage cam 15 which is provided in the elevator shaft at each floor of the building.

The second rigid link 11 is connected to an electromagnetic actuator unit 16 which is operated by a solenoid and is controlled by a central elevator control unit.

In normal operation of the elevator, when the elevator car is moving a signal is sent from the central control means to the actuator 16 to cause the actuator 16 to move rigid link 11 upwardly, as viewed in the drawing. This upward motion of the link 11 causes the locking member 6 to pivot, clockwise about pivot point A, into the third position in which notch 9 engages pin 4 to lock the door suspended from door hanger 2. Since the doors are interlinked as described above, the other door is also locked. Thus during normal travel of the elevator car up or down the elevator shaft, the doors are locked by the locking member 6 being in its third position with notch 9 engaging pin 4.In this position it is to be noticed that the operating element 12, connected to locking member 6 through link 10, is swung away from the wall of the elevator shaft so that the roller 13 does not engage the cams 15 as the car moves up and down the shaft.

If the elevator car comes to a halt at a floor in response to a car or landing call for such a floor, the central control means switches off the actuator and, owing to the weight of the rigid link 11 the locking memeber is pivoted counterclockwise until roller 13 engages cam 15 and the locking mechanism is in the position shown in the drawing in which the doors may be opened.

In the event that the elevator car comes to a halt, for whatever reasons, at a position other than at a floor, the roller 13 does not contact a cam 15 and the counter-clockwise rotation of the locking member 6 continues until the first position is reached in which notch 8 engages pin 3 to lock the doors. In particular, in the event of a power failure when the car is not at a floor the actuator 16 is released, since it is electrically operated, and the locking member 6 is pivoted by the weight of the link 11 into its first position.

The elevator car can then be wound by hand to a floor at which point roller 13 engages cam 15 to move the locking member 6 into its second position in which the doors may be opened.

A microswitch 17 may also be provided which is adapted to detect when the locking member 6 is in the second position. This microswitch may be used to ensure that no attempt is made to open the doors unless the locking member 6 is in its second position.

The cams 15 may be of any desired length, but preferably they are about 10 inches long.

This allows the elevator car to be considered to be "at a floor" within 5 inches of being exactly level with the floor.

Claims (10)

Claims:

1. A locking mechanism for the door(s) of an elevator car, comprising a locking member arranged to move to a first position wherein the door(s) is/are firmly locked when the car is between floors of a building at least in the event of failure of the power supply to the elevator, such member being mechanically coupled to an operating element arranged to co-operate with a cam member associated with the elevatot shaft adjacent each floor in such a way that the locking member is held in a second position when the car is at or adjacent a floor wherein the door(s) may be opened.

2. A locking mechanism according to claim 1 wherein said locking member is gravity or spring biased into the locked position and the operating element is adapted to move the locking member against the biasing force when the car is at a floor.

3. A locking mechanism according to claim 1 or 2 wherein an acutuator is provided adapted to retain the operating element in a retracted position in which it does not engage the cam members at least when the car passes a floor during normal operation of the elevator, such an actuator being disabled in the event of a power failure.

4. - A locking mechanism according to claim 3 wherein the actuator is electromagnetically operated.

5. A locking mechanism according to claim 3 or 4 wherein the retracted condition of the operating element corresponds to a third position of the locking member in which the door(s) are also locked, the actuator being responsive to control means for the elevator so as to release the locking member and operating element when the car is stationary at or adjacent a floor in response to a car or landing call for such floor, so that the locking member moves to its second condition with the operating element engaging the respective cam so that the doors may be opened.

6. A locking mechanism according to claim 5 wherein the locking member comprises a pivotable bar having a notch at each end engageable with a respective pin associated with said door(s), and said first and third positions correspond to a position in which respective notches engage a pin, and said second position corresponds to a position in which neither notch engages a pin.

7. A locking mechanism according to any preceding claim wherein the operating element comprises a roller mounted on one end of a roller arm, the other end of said roller arm being connected to said locking member by means of rigid link.

8. A locking mechanism for the door(s) of an elevator car substantially as hereinbefore described with reference to the accompanying drawing.

9. An elevator car incorporating a locking mechanism according to any preceding claim.

10. An elevator system including at least one elevator car as claimed in claim 9.