GB2072138A - Monitoring lift systems - Google Patents

Abstract

A lift system comprises a lift car 7 in a lift shaft 8 and electrically connected to a control panel 5 and a monitor panel 3 arranged to provide an alarm output signal on cable 2 when activated by the lift car ON/OFF alarm switch depending upon the condition of a continuity circuit (Fig. 5) (not shown). The continuity circuit is formed by sensors respective to the condition of the lift car door 11, the landing door 14 and the level A, B, etc. at which the car 7 is located. The lift car door condition is monitored by sensor arrangement 12, 13, the landing door condition by sensor arrangement 15, 16, and the car level by sensor arrangement 9, 10. When the alarm switch is moved to its ON position by a lift car passenger and the continuity circuit indicates a safe exit condition for the lift car 7 panel 3 initiates in panel 5 a signal to move the lift car 7 to a predetermined floor level (e.g. ground level) and the monitor panel self resets thereafter if the continuity circuit continues to indicate a safe exit condition but in the converse situation issues an alarm signal. <IMAGE>

Description

SPECIFICATION Vertical transportation lift systems This invention relates to vertical transportation lift systems.

Vertical transportation lifts are commonly located in areas to which the public have access and as a result are commonly subjected to vandalism. Within each lift car there is an electrical push button panel for operation by a passenger in the lift, whereby the passenger can operate the lift to move from one level to another.

This panel also incorporates an ON/OFF 'alarm' push button which is intended to provide an alarm signal to the lift supervisor when a passengerfinds himself trapped within a lift car. Unfortunately, the accessibility of the 'alarm' push button permits its incorrect use by vandals so that alarm signals received by the supervisor do not invariably indicate the presence of a trapped passenger but invariably require corrective action to be taken by the supervisor. This is wasteful of manpower and leads to the supervisor having a tendency to ignore alarm signals.

It is an object of the present invention to provide a vertical transportation lift system with an improve alarm system which obviates or mitigates the foregoing disadvantages.

According to the present invention there is provided a vertical transportation lift system comprising a lift car with an alarm circuit including an ON/OFF switch, monitoring means electrically connected with the alarm circuit and means for emitting an alarm signal in response to an output signal from the monitoring means wherein, in response to said ON/OFF switch being moved to the ON position, the monitoring means is arranged to monitor the status of a continuity circuit during a predetermined time interval, and to emit said output signal in response to the continuity circuit being in a predetermined condition at the end of said time interval, said continuity circuit comprising sensors for detecting the open or closed condition of the lift car door, the open or closed condition of the landing door at which the lift car is located and the level at which the lift car is located.

Preferably during said time interval the monitoring means provides a signal to move the lift car to a predetermined level.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 shows the general electrical arrangement; Fig. 2 shows the general mechanical arrangement in vertical section; Fig. 3 shows the general mechanical arrangement in horizontal section; and Figs. 4-12 illustrate details of the electrical circuitry; normally open relay contacts being shown with the bar above the contacts and normally closed with the bar beneath the contacts.

In Fig. 1 of the drawings the general electrical arrangement is for a lift system having four cars each with a control panel 5 normally located in the lift motor winding room and interlinked by cabling 6A to the standard lift-shaft connection box 6C (see Fig. 2). Each panel 5 is interlinked by cable 4 to a monitor control panel 3 which receives a power supply on cable 1, provides an alarm output, if necessary, on cable 2 and communicates with the lift cars and shafts, as will be explained, by cable 6A. In Fig. 2 the lift car 7 is movable vertically in shaft 8 and is controlled in conventional manner to stop at the various floor levels of which two are illustrated as A and B. The lift car 7 carries a position sensor 9 which is actuated by device 10 mounted in the shaft 8 when the car is correctly aligned with level A.The car 7 also has a door 11 carrying a device 12 which is actuated by a sensor 1 3 mounted in the shaft 8 and at floor level A there is a landing door 14 carrying a device 1 5 which is actuated by a sensor 16 mounted in the shaft 8. The shaft 8 also accommodates the conventional counterweight 17 (Fig. 3) for the lift car 7. In the arrangement shown in Fig. 3 two lift cars 7 are accommodated side by side but this is merely one mechanical arrangement which is possible and many others are possible without departing from the inventive system to be described. Conveniently however one of the two lift cars of Fig. 3 is programmed to stop at odd numbered levels A, C, E etc. whilst the other lift car stops at even numbered levels B, D, F etc.

The push button panel in each lift car 7 has an alarm circuit including an ON/OFF switch for manual actuation by a trapped passenger and in order to actuate the monitor panel 3 a relay coil is connected in the alarm circuit so that when the alarm switch is in the ON condition the relay coil is energised. This is shown in Fig. 4 where coil RE is provided in the car stopping at even numbered floors and coil RO is provided in the car stopping at odd numbered floors.The panel 3 is connected by cable 6B to the continuity circuit of Fig. 5 where switch 1 8 is the car door switch which closes when the car door is open by means of device 1 2 and sensor 13, and appropriate to each level at which the car stops there is a car position switch 19 which closes when the car is correctly positioned by means of sensor 9 and device 10 and landing door switch 20 which closes when the landing door is open by means of device 15 and sensor 1 6. The continuity circuit has terminals 21, 22 which are connected via cable 6B to the location of the switches in the shaft 8 and the various contacts of relay coils RE and RO are likewise connected via cable 6B or 6A to the panel 3.

In the panel 3 there are the circuits shown in Figs. 6-12 and when either RE or RO is energised as a result of an alarm condition relay R1 and the appropriate one of relays RA and RD become energised. RA is energised if RE is energised and RD is energised if RO is energised. Normally closed contacts RA/2 and RD/2 provide an electrical interlock to prevent RA and RD being energised simultaneously. With R1 energised R2 is also energised which results in motor 25 (Fig. 7) being snergised so that the various cam-operated switches CS1-CS7 (Fig. 8) are actuated.Initially only contact CS4 is closed (thereby causing a monitoring lamp L5 to be illuminated) but after a few degrees of movement of the motor 25 CS4 is moved to the open condition and the contact CS7 for the motor 25 becomes closed for the purpose of manually resetting the cam timer motor 25 to the start position. CS5 operates warming lamp L6 and becomes closed at the same time as contact CS1 which is connected in series with relay R3 and the continuity circuit of Fig. 5.If at this stage the circuit of Fig. 5 has continuity thereby indicating a condition of safe exit from the lift car from which the alarm signal was initiated as determined by the circuit of Fig. 11 R3 becomes energised and self latched by contact R3/2 and normally closed contact R3/1 is moved to the open condition thereby rendering relay R4 unenergisable so that normally open contact R4/3 is maintained open and no alarm signal can be emitted on cable 27 (Fig. 9).

Shortly after CS1 is closed CS3 is closed for a short period resulting in a signal being sent to the appropriate control panel 5 to simultate a 'move to ground level signal' (Fig. 10). This signal is received by panel 5 just as though a passenger had pushed the 'ground level' push button on the ground floor and causes the car to move to ground level where, in the absence of a true alarm condition, the circuit of Fig. 5 will provide continuity arising from the normal operation of the control panel 5 and the remainder of the lift control system (i.e. correct alignment of the lift car and opening of both car and landing doors).

Thereafter the motor 25 will automatically reset to the start position. If a true alarm condition persists circuit Fig. 5 remains open circuit so that relay R3 is not energised and contact R3/1 is closed and when CS2 closes towards the end of the cam cycle relay R4 energises, opens contact R4/1 to de-energise the motor 25 and outputs on alarm signal on cable 27 by closing R4/3.

When the alarm condition is corrected by manual intervention of a lift supervisor the manual reset button 28 (Fig. 7) can be actuated to return motor 25 to its initial condition thereby reenergising relay R6 and opening the reset contacts of R6 in the circuits containing RA and R2.

Relay R5 is connected across the voltage supply within the monitor control panel 3 and in the event of voltage failure contact R5/1 provides an alarm signal on cable 27. A manual test switch S1 is provided to energise relay R2 for test purposes in order to simulate an alarm condition within the monitor panel 3.

It is to be noted that CS2 is open for a time interval sufficient to permit the lift car to move from its most remote position to the ground level (or such other pre-designated level as may be considered convenient) so that the panel 3 can monitor the continuity circuit of Fig. 5 firstly when the ON/OFF alarm switch is actuated and secondly after the lift car has been moved to the predesignated level. Only after this period of time has elapsed does CS2 close to permit an alarm signal to be output if the continuity circuit of Fig. 5 persists in indicating a true fault condition.

The continuity circuit of Fig. 5 operates on the basis of the sensors 9, 1 3 and 1 6 consequently any serious vandalism which results in malfunction of these sensors will result in the continuity circuit producing an alarm condition in the event of the alarm ON/OFF switch being actuated.

Fig. 12 illustrates an array of warning/indicating lamps which can be used to monitor the condition of the panel 3. These lamps are not essential but are convenient for fault location. L1 designates that there is an alarm call from a lift car; L2 that there is no alarm call from any lift car; L3 that the voltage supply in panel 3 is energised; L5 that the cam motor 25 is in its reset position; L6 that motor 25 is running; L7 that an alarm call is confirmed and set awaiting supervisory action; L8 that there is no alarm signal; L9 that the continuity circuit indicates absence of an alarm condition; L10 that the continuity circuit indicates the presence of an alarm condition; LO that an alarm call has been received from the lift car stopping at odd numbered floors; and LE that an alarm call has been received from the lift car stopping at even numbered floors.

Although the embodiment utilises electromagnetic relays it will be appreciated that solid state, transistor or microprocessor implementations are equivalent and of course, the alarm signal on cable 27 may be transmitted by P.O. land lines or radio either to a local or a remote station for the attention of the lift supervisor.

Although relays RE and RO are shown in Fig. 4 as being connected directly in series with the respective ON/OFF alarm push buttons of the lift cars these relays can alternatively be connected in parallel with the alarm bells contained within the control panels 5 and which are remotely actuated by the alarm ON/OFF push buttons.

Claims (4)

1. A vertical transportation lift system comprising a lift car with an alarm circuit including an ON/OFF switch, monitoring means electrically connected with the alarm circuit and means for emitting an alarm signal in response to an output signal from the monitoring means wherein, in response to said ON/OFF switch being moved to the ON position, the monitoring means is arranged to monitor the status of a continuity circuit during a predetermined time interval, and to emit said output signal in response to the continuity circuit being in a predetermined condition at the end of said time interval, said continuity circuit comprising sensors for detecting the open or closed condition of the lift car door, the open or closed condition of the landing door at which the lift car is located and the level at which the lift car is located.

2. A lift system as claimed in claim 1, wherein during said time interval the monitoring means provides a signal to move the lift car to a predetermined level.

3. A lift system as claimed in either preceding claim, wherein said predetermined condition is indicative of the lift car door being closed in combination with the lift car incorrectly located relative to a landing level and the relevant landing door being closed.

4. A vertical transportation lift system substantially as hereinbefore described with reference to the accompanying drawings.