GB2214488A

GB2214488A - Lift control

Info

Publication number: GB2214488A
Application number: GB8801201A
Authority: GB
Inventors: David Michael Yates
Original assignee: PROPBROOK Ltd
Current assignee: PROPBROOK Ltd
Priority date: 1988-01-20
Filing date: 1988-01-20
Publication date: 1989-09-06
Anticipated expiration: 2008-01-20
Also published as: GB8801201D0; GB2214488B

Abstract

A lift comprising a lift car (11) (Fig 1 not shown) having a door operating means (22) to open and close a door, sensor means (60, 69) to sense at least when the door (21) is fully closed, a control means carried on the lift car (11) operative to control the door operating means (27), the control means being responsive to the sensor means (60, 69) to provide a signal to a lift controller (C) to indicate when the door (21) is fully closed.

Description

Title: "Lifts" Description of Invention This invention relates to a lift of the kind comprising a lift car for raising and lowering passengers or goods for example in a building.

Conventionally, lifts comprise a prime mover located above or below a lift shaft or track for the lift car (hereinafter called "a lift shaft") and a cable is wound by the prime mover to raise or lower the lift car.

The lift car conventionally has a door which is closed when the lift car is moved up and down and automatically opened by door operating means at stopping positions e.g. at landings where passengers for example may enter or leave the lift car.

The door operating means and all other services to the lift car such as passenger operated controls which cause the door to open/close and the lift car to stop at selected floors, are conventionally connected to a lift controller located in a fixed position e.g. in a control room where the prime mover is located.

Thus it has been necessary to provide a travelling flex in order to make the necessary electrical connections between the lift car and the controler.

The travelling flex needs to be at least as long as the lift shaft is shiah so that the necessary electrical connections are achieved between the lift car and the controller wherever the lift car is within the lift shaft.

However it will be appreciated that as the lift car is raised and lowered, the travelling flex will be subjected continuously to bending and flexing.

To provide a flex which is sufficiently robust yet flexible, is necessarily expensive and further, the more individual connections or cores within the flex which need to be provided to achieve connections between the lift car and the controller, the thicker and hence more expensive the flex.

Furthermore, maintenance on door operating means of conventional lifts is complicated because mechanical and electrical adjustments need to be made simultaneously in the control room to the lift controller and to the door operating means, for the door operating means to operate correctly. This requires two lift maintenance workers one located on the lift car and the other in the control room, to have voice communication.

It is an object of the present invention to provide a new or improved lift which overcomes or reduces these problems.

According to one aspect of the invention we provide a lift comprising a lift car having a door operating means to open and close the door, sensor means to sense at least when the door is fully closed, a control means carried on the lift car operative to control the door operating means, the control means being responsive to the sensor means to provide a signal to a lift controller to indicate when the door is fully closed.

Thus the number of individual connections or cores in the travelling flex between the lift car andthe controller is considerably reduced. so that only a relatively thin and therefore less expensive travelling flex is required extending between the lift car and control room, which results in a considerable cost saving.

There is no need for multiple connections between the lift controller and the door operating means as required with conventional lifts to enable the controller to control the door operating means.

Furthermore, the arrangement considerably facilitates the carrying out of maintenance on the door operating means of the lift car, because there is no need for communication between a pair of maintenance workers, one located on the lift car, and the other in the control room.

Using modern solid state technology, the control means may be positioned at any convenient position in or on the lift car, but conveniently, the control means is provided at or adjacent the door operating means.

Preferably, the sensor means is also able to sense the fully open position of the door and provide a signal to the lift controller to indicate when a door is fully open.

Where movement of the door between its fully open and fully closed positions is complex, i.e. the door is moved at different speeds during different extents of its movement, the sensor means is preferably able to sense the position of the door at a plurality of positions during its movement, and provide intermediate position signals to the control means which operates the door operating means in the required manner. However, unlike with conventional arrangements there is no need for these intermediate position signals from sensor means to be transmitted to the lift controller because the door operating means is controlled by the control means.

Conventionally, the lift controller may be responsive to sensing means provided on the lift car which sense the position of the lift car in the lift shaft, and a control panel provided in the lift car for use by lift users, as well as to controls provided at each stopping position for the use of potential lift users, and to any safety devices which may be associated with doors positioned at each stopping position.In accordance with the invention, the lift controller may be responsive to the control means of the lift car to determine when the lift car may be moved, and the manner in which the lift car may be moved and the controller may provide a simple signal to the control means of the lift car to instruct the control means to operate the door operating means to open or close the door in the required manner only when the lift controller determines that the lift car is stationary and at a recognised stopping position such as a landing of a floor.

Sensing means to sense the position of the lift car in the shaft, may be provided at any desired position on the lift car and may respond to passive or active signalling devices which are positioned along the lift shaft to signal the lift controller and indicate the position of the lift in the lift shaft.

According to a second aspect of the invention we provide a door operating means for a lift according to the first aspect of the invention, in combination with a control means.

For example, the door operating means may comprise a sub assembly which provides a mounting for the control means.

The invention will now be described with the aid of the accompanying drawings in which: FIGURE I is an illustrative purely diagrammatic view of a lift in accordance with the invention, FIGURE 2 is a side view of a door operating mechanism of a lift in accordance with the invention, FIGURE 3 is a plan view of the mechanism of Figure 2.

FIGURE 4 is an end view of the mechanism of Figure?, FIGURE 5 is a sectional side elevation of the door opening mechanism of Figures 2 to 4.

Referring to figure 1, a lift comprises a lift shaft 10 up and down which a lift car II travels to convey passengers and/or goods between floors 12,13,14, of a building.

Beneath the lift shaft 10 is an inspection pit 15 and above the lift shaft 10 is a control room I in which a prime mover 17 i.e. an electric motor is housed, the motor being connected via a suitable transmission to a winding drum 18. The drum 18 carries a cable 19 which is connected to the lift car 11 and to a counterweight 20 which travels up and down the lift shaft 10 in an opposite direction to the lift car I I, to counterbalance the lift car.

Also located in the control room 16 is a lift controller C which is responsive to various signals as explained below to operate the motor 17.

Extending between the lift car 11 and the controller C is a travelling flex T which is at least as long as the lift shaft 10 is high, plus the depth of the inspection pit 15.

The lift car II has a door 21 which opens when the car has stopped at each floor landing 12-14 to permit passengers/goods to enter and leave the lift car 11 at each floor.

The door 21 is opened and closed by a door operating means 22 which is only shown diagrammatically in figure 1, but is described in more detail with reference to figures 2 to 5 below.

Of course, on a landing of each floor 12 to 14, one or more doors 23 are also provided which are normally closed but which are opened when the car 11 stops at the respective floor by the door operating means 22 of the car 11.

The construction of doors 23 plays no part in the invention and hence will not be described in detail here.

Further associated with each floor 12 to 14, are passive proximity devices 27a, 27b, 27c respectively, which co-operate with sensing means 83 on the car when the lift car 11 is at a respective floor, and further passive proximity devices 28a-28d are provided in the lift shaft 10, which co-operate with the sensing means 83 of the car 11 when the lift car is approaching a floor 12 to 14 so that the speed of the lift car II may be reduced prior to being stopped at the respective selected floor, and when the lift car II has left a floor, so that the speed of the lift car 11 can be increased over at least part of the travelling distance between floors, as hereinafter explained.

Conventionally, the travelling flex T carries a large number of individual cores to provide connections between the lift car II and the controller C in the control room 16. In particular, conventionally the travelling flex 21 would enable power to be transmitted from the control room 16 to the car II, for example to power lights, and signals to be sent to a door operating means whereby the door operating means is controlled directly from the controller C. Further connections would be required to enable signals from the sensing means 83 provided on the car II to be sent to the controller C to indicate when the lift car II is approaching a respective floor, or is at a respective floor, so that the lift car I 1 can be stopped at a selected floor and the door opened.Still further connections are conventionally required to connect a control panel 25 of the car 11 to the controller C. The controller C is also responsive to signals from further controls such as may be provided on each floor to enable potential lift users to "call" the lift and to signals from safety devices provided at each floor which confirm when the lift car 11 is stationary at that floor.

In accordance with the invention, the travelling flex T comprises many less cores than are conventionally required because the control of the door operating means 22 is via a control means carried by the lift car and not directly from the controller C in the control room 16.

Referring more particularly to figures 2 to 5, the door operating means 22 includes a door opening mechanism 24 which includes a motor 30 which is mounted on a support frame 31 and drives an intermediate wheel 32 via a drive belt 33.

The intermediate wheel 32 is carried on a shaft 34 which rotates a drive spigot 35 which in turn transmits drive to a chain drive wheel 36 via a chain 37.

The drive wheel 36 carries a link 38 on a drive pin 39 which is connected via a pivotal connection 40 to a further link 40' which is pivotally connected to a door operating arm 41.

The length of link 40' is adjustable to adjust the sliding distance of travel of the door 21. The arm 41 itself is pivoted to a mounting plate 41' and to the lift car door 21. As is well known in the art, the arm 41 may operate a release means of a lock mechanism which normally retains the lift doors 23 on each landing 12,13,14, in a closed position, when the lift car 11 is stationary at a respective floor, when the arm 41 can engage the release means.

Using the arrangement described, the drive wheel 36, by rotating anticlockwise as seen in figure 2, less than one complete revolution, will move the arm 41 to close the door 21 and conversely, when moved clockwise as seen in figure 2, back to the position shown through less than one complete revolution, the door 21 will be opened fully.

Preferably, the drive wheel 36 has an associated mechanical stop 43 so that movement of the door 21 is arrested when the stop 43 abuts an abutment B (see figure 3) as the door 21 reaches its fully open position.

The plate 41' is itself pivotally mounted for movement about a pivot axis A, but this movement is resisted by a spring S which acts through a pin P on the free end of the mounting plate 41'.

In the event that on closure of a door, either the landing door 23, or the lift car door 21, resistance is experienced before the door has reached its fully closed position, for example, if a lift users hand becomes trapped by the door, the plate 41' will pivot against the force of the spring, and actuate a microswitch 45 which will cause the motor 30 immediately to be operated in a reverse direction so that the doors will be immediately opened to release the lift user.

More elaborate safety devices may be provided as required for example to positively lock the lift car door 21 against being forced open when the lift car 11 is not stopped at one of the floors 12 to 14.

The door operating means 22 comprises a sub assembly carried on an upstanding plate 50 of a support frame 52 on which a control means 44 is provided. The control means 44 includes a printed circuit board 51 carrying electronic solid state components and electromechanical relays 53, as necessary to provide an electrical control circuit for controlling operation of the door operating mechanism 22.

The support frame 52 includes a base plate 54 carried between a pair of generally Z section rails 55, and the shaft 34 on which the intermediate wheel 32 is carried, and a shaft 56 on which the chain drive wheel 36 is carried, are each mounted on an upper plate 57 of the frame 52 so that the intermediate wheel 32 lies on one side of the plates 54,57, whilst the chain drive wheel 36 lies on another side of the plates 54,57.

Between the plates 54 and 57 is mounted a transformer R and a large capacity smoothing capacitor C' which are also each connected in the control circuit.

The drive shaft 56 which carries the drive wheel 36 includes a plurality of cams 60 to 69 of a sensor means which cams, as the drive wheel 36 rotates, operate corresponding microswitches 70 to 79 which are also connected in the control circuit so that the position of the wheel 36 and hence of the door 21 can be determined at a plurality of positions by the sensor means, as the door 21 is opened and closed.

It will be noted that the position of the shaft 34 which mounts the intermediate wheel 32 can be adjusted by adjustment means 80 to tension the chain 37 and the belt 33 can be tensioned by raising or lowering the motor 30 on plate 31.

Further, the microswitch 45 is connected to the control circuit by leads which pass through a conduit 81, and a bracing means 82 is provided on a mounting M of the mounting plate 41' on which the switch 45 is mounted and the lower flange of the Z shaped rail 55.

Operation of the lift will now be described.

Beginning with the lift car Il on the ground floor 12 of the building, a lift user may cause the door 21 to close by selecting a floor 13 or 14 to which the user wishes the lift to travel, by pressing an appropriate button or the like on the control panel 25.

This signal is transferred to the controller C in the control room 16 which determines the logical movements of the lift car and then signals the control means 44 to close the doors 21,23.

This closure of the doors 21 and 23 is controlled entirely by the control means 44 of the door operating means 22.

As will be appreciated by those skilled in the art, lift doors are usually arranged first to move slowly from a closed or open position over an initial travelling distance, and then to move quickly over an intermediate travelling distance, and over a final travelling distance, as the doors approach a fully open or fully closed position respectively, the doors are again arranged to move at a slow speed.

By virtue of the sensor means comprising the cams 60 to 69 and microswitches 70 to 79 carried on shaft 56, the position of the door 21 during opening and closing can be determined by the control means 44 which operates the motor 30 appropriately at an appropriate speed during the various extents of travel of the doors to achieve the required door opening/closing characteristics.

When the sensor means senses that the arm 41 is in a fully closed position, the control means 44 may thus deactivate the motor 30 and activate any door locking device which may be provided. Conventionally, as the doors 21,23 reach their fully closed positions, the arm 41 disengages the release means of the locking mechanism associated with the landing doors 23 which thus become locked in their closed positions. At the same time, any safety switch provided on the landing door 23 signals the lift controller C that the door 23 is in a properly fully closed position. Simultaneously, the control means 44 of door operating means 22 sends a signal along the travelling flex T to the controller C in the control room 16 to indicate that the lift door 21 is closed.The controller C is then able to activate the prime mover 17 to cause the lift car 11 to travel along the lift shaft 10 to the users selected floor, or a floor 12-14 determined by the logic of the lift controller C. Of course, any brake which may be applied to the winding wheel 18 needs to be released by the controller C before the lift car 11 can move.

The lift car II moves upwardly initially slowly as the inertia of the lift car 11 is taken up by the winding mechanism, to provide a minor jolt to persons/goods in the lift car. Eventually the lift car 11 will reach full speed.

If desired, in a modified arrangement, after an initial travelling distance when the lift moves slowly, the proximity device 28a for example on the first floor will actuate the sensor means 83 of the lift car II which will signal the controller C to cause the prime mover 17 to raise the car at an increased speed for an intermediate travelling distance between floors.

In each case, assuming that the user has selected the first floor 13, when the device 28b actuates the sensing means 83 of the lift car II, the sensing means 83 will signal the controller C which responds by decreasing the lift car speed over a final travelling distance.

When device 27b actuates sensing means 83 to sense the car 11 position, the sensing means 83 signals the controller so that the prime mover 17 will be deactivated and any brake applied to the winding wheel 18.

When movement of the lift car II has stopped the sensing means 83 on the lift car II senses the device 27b and provides an input to the controller C. If the controller also receives a signal from a safety device on the landing 13 to indicate that the lift car II is properly in a recognised stopping position, the controller signals control means 44 of the door operating means 22 of the lift car to open the doors 21,23.

The door operating means 22 responds to the control means 44 by again opening doors 21,23, the motor 30 being energised first to move the doors 21,23, slowly over an initial travelling distance and then more quickly over an intermediate travelling distance and finally, slowly over a final travelling distance. When the door 21 is fully open, the sensor means will signal the control means 44 to deactivate the motor 30.

If desired, the control means 44 may cause the door 21 to be closed again automatically after a predetermined time, but alternatively, when the doors 21,23, are in a fully open position, the sensor means of the lift car signals the lift controller C which returns a signal to the control means 44 after a predetermined time, to again close the doors 21,23. The controller C may then return the lift car II to the ground floor 12 or may move the lift car to another floor if any "call" button has been operated on a control on any selected floor by a potential lift user.

If instead of selecting floor 13, the user had selected floor 14, the sensing means 83 would be rendered inoperative to the devices 28b,27b by the controller C so that the lift car 11 would travel to floor 14 without stopping at floor 3. However, if a further user were to "call" the lift car II by operating an appropriate control at floor 13 i.e. a call button, the devices 28b and 27b may again actuate the sensing means 83 which signals be rendered operative by the controller C so that the lift car 11 would stop at floor 13 before proceeding to floor 14.

Device 28a provided in the lift shaft 10 is sensitive to the approaching lift car 11 as the lift car returns to ground floor 12, to cause the speed of descent of the lift car II to decrease over a final travelling distance.

Device 28d is operative to cause the lift car 11 to slow down as the lift car 11 approaches its stopping position on floor 14 and device 27c is provided to actuate the sensing means 83 when the lift car 11 has reached its stop position on floor 14. Device 27b operates the sensing means 83 which the lift car has reached its stop position on floor 13 and device 28b operates sensing means 83 to signal controller C to cause the prime mover 17 to slow down the rate of ascent, or to speed up the speed of descent as the lift car 11 approaches or leaves floor 13, respectively.

The travelling flex 21 carries power to the lift car 11 to operate lights etc. but the transformer R is operative to provide an appropriate current supply to the control means 44.

Various modifications may be made without departing from the scope of the invention. For example, the door operating mechanism 24 described with reference to figures 2 to 5 particularly, is only an example of a door operating mechanism which may be used in a lift according to the invention.

Although the control means 44 is described as being provided on a sub assembly of the door operating means 22, it will be appreciated that the control means 44 could be provided in other positions if required, on the lift car 11, although the position described has been found to be the most convenient.

The control means 44, in particular the control circuit thereof, may include microprocessor means suitably programmed for operation of the door operating means 22, and if desired, the electromechanical relays 53 could be replaced by appropriate solid state switches.

It is again emphasised that the lift shown in figure I is only an example of a lift in accordance with the invention and many modifications are possible. For example, the building only has three floors, whereos of course, a building having any number of floors may be provided with a lift in accordance with the invention.

As described, the devices 27a-27c and 28a-28d are passive signalling devices which actuate the sensing means 83, although could be active signalling devices if required, with an passive sensing device being provided on lift car 11.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS:

I. A lift comprising a lift car having a door operating means to open and close the door, sensor means to sense at least when the door is fully closed, a control means carried on the lift car operative to control the door operating means, the control means being responsive to the sensor means to provide a signal to a lift controller to indicate when the door is fully closed.
2. A lift according to Claim I wherein the signal is carried by a travelling flex which extends between the lift car and a control room.
3. A lift according to Claim I or Claim 2 wherein the control means is provided on the lift car at or adjacent the door operating means.
4. A lift according to any one of Claims I to 3 wherein the sensor means also senses the fully open position of the door and provides a signal to the lift controller to indicate when a door is fully open.
5. A lift according to any one of the preceding claims wherein movement of the door between its fully open and fully closed positions is complex, in that the door is moved at different speeds during different extents of its movement.
6. A lift according to Claim 5 wherein the sensor means senses the position of the door at a plurality of positions during its complex movement, and provides intermediate position in formation to the control means which operates the door operating means in response.
7. A lift according to any one of the preceding claims wherein the lift controller is responsive to the control means of the lift car to determine when the lift car may be moved, and the manner in which the lift car may be moved.
8. A lift according to Claim 7 wherein the controller provides a simple signal to the control means of the lift car to instruct the control means to operate the door operating means to open or close the door only when the lift controller determines from the control means that the lift car is stationary and at a recognised stopping position.
9. A lift according to any one of the preceding claims wherein sensing means to sense the position of the lift car in the shaft, are provided on the lift car and are responive to passive or active signalling devices which are positioned along the lift shaft.
10. A lift substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
II. A door operating means for a lift according to any one of the preceding claims in combination with a control means.
12. A door operating means according to Claim II which comprises a sub assembly which provides a mounting for the control means.
13. A door operating means substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
14. Any novel feature or novel combination of features disclosed herein and/or as shown in the accompanying drawings.