GB2241797A

GB2241797A - Lift call device

Info

Publication number: GB2241797A
Application number: GB9101818A
Authority: GB
Inventors: David Hernandez Benolier; Salvador Anchel Rubio
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-02-01
Filing date: 1991-01-28
Publication date: 1991-09-11
Anticipated expiration: 2011-01-28
Also published as: ITUD910016A1; GB9101818D0; FR2657594B1; FR2657594A1; GB2241797B; JPH04213572A; IT1248127B; ES2020839A6; DE4102926A1; ITUD910016A0

Abstract

An automatic call device for lifts consists of a photo-detector or a passive infra-red detector 1 to generate a potential difference when a person enters its field of action. The device includes a delay unit 2 to prevent premature activation due to accidental interruption of the ray. The output of the delay unit operates a trigger unit 2 such as a monostable multivibrator or Schmitt trigger which controls 3 operation of a lift motor either directly by activating the power supply to the lift motor, or indirectly through a microprocessor. The photodetector may operate by the person breaking a light ray or an infra-red ray or by the person obscuring the ambient light reaching a photosensitive element. <IMAGE>

Description

1 :2:2 _el 1L -7 1E3 "I" 1 AUTOMATIC CALL DEVICE FOR LIFTS The invention

relates to automatic call detectors for lifts and elevators.

The present mechanism for calling lifts incorporates the well known pushbutton panels, in standard lifts as well as those with memory, and to date, there are no automatic call methods or apparatus activated by the presence alone of the user on any floor using sensors or photosensi.tive cells.

The present invention provides an automatic lift call device incorporating a sensor, the presence of a user causing the sensor to activate the device to automatically call the lift. Preferably the device, when activated, gives off an acoustic signal.

Preferred sensors are passive infra-red detectors or photocells.

In a preferred embodiment the detecting device consists a unit in which is applied the basic principle of the optical electronic transducer, and incorporates a function unit which detects a body by interruption of a ray of light. That light may be emitted by the unit itself, in which case its interruption would activate the unit, or otherwise, by allowing ambient light to reach or not to reach a photosensitive element. Each of the possibilities would produce the same effect.

The system has the advantage of giving the user extra comfort, as well as being of considerable help at those moments when hands are not free to push the lift call 0 0 2 button. It is also very useful for those members of the public such as the disabled or the blind. The f ormer because their presence alone would activate the lift without them having to put themselves in danger by an awkward or unusual movement, and the latter because interrupting the ray of light would set off an acoustic signal letting them know that the lift has been called and where to step.

All this, as well as the system's benefits in cargo lifts in industry, hotels, hospitals and other locations, make this device versatile and high-performance, as the unit acts as an automatic call switch.

In general terms, one automatic detector lift calling device can be defined as a block diagram electrical circuit; the diagrammatic definition of which will define each block's function, without unessential detail in the functional electronic design, as each block's purpose could be carried out by various types of electrical circuit. A difference of detail may be required, depending on the characteristics of the lift; for example whether it has a memory or not. The difference between devices suitable for memory and no-memory lifts lies in a final part of the diagram, where lifts without memory will have an additional block to cover the lift motor voltage/current requirements. In a preferred embodiment operation starts when the user interrupts the ray of light thus activating a photosensitive cell; the potential difference of the pulse at the cell output activates a trigger circuit, generating a pulse at 3 its output of a length which depends on the time the ray of light is interrupted. Once the ray of light is no longer interrupted there will be no potential difference at the sensor output, and thus the trigger circuit will no longer receive that potential at it ' s Input, and there will also be zero potential at its output causing the lift motor to cease its activity.

In order to better understand the general characteristics described above, there are accompanying diagrams which give a diagrammatic scheme representation of the working block diagrams of a preferred embodiment of the automatic detector lift calling device described herein, It is hereby stated that the figures described below must be considered representative only.

The figures represented in the diagrams attached show the following:

Figure 1. Block diagram of the electrical circuit including a light sensor, trigger and control circuit; and Figure 2. Block diagram of the power source with 220 volt, 50 Hz. AC mains power input and stabilised, controllable and short-circuitable DC output.

The reference numerals of the accompanying diagrams represent the following:- (1) The light sensor block. As the optical sensors are devices planned to achieve a high level of detection, : 0 zo 4 their working principle is based on optical electronic concepts. The devices are able to emit a ray of light, which may be based on a photoconductive element or on the modulated emission of infra-red rays.

The former has an internal semiconductor lit by photons of energy not less than the threshold value of the semiconductor, and will be activated and thus generate a difference in potential the moment a person enters its field of view. This potential acts on a retarding or timing unit, intended to produce a delay in the time between the moment when it is activated by the sensor, and the moment when the potential reaches the subsequent block.

The latter has the advantage of being unaffected by changes in ambient or external light.

(2) The trigger circuit, in which timing means act to verify the call and give it consistency, thus avoiding starting of the lift motor due to accidental interruption of the ray. Detection is carried out by reflection when an object (caller) returns the light it receives, or by direct incidence. The effective detection distance may be varied according to the conditions of the point to be located.

The pulses detected and provided by optical electronic attraction need to be formed to give them the characteristic voltage/current required to activate the lift motor, thus the output pulse from the light sensor (1), acts on the trigger circuit (2), which is constituted by rectangular voltage pulse generators or state formers. Among the range of circuits which can carry out this function are:

a. Monostable multivibrators (circuits which only have one stable state which changes according to the pulse present at the input, although this state is transitory, depending on the discharge process of a condenser. That is to say, that there is a voltage of zero at its output, which corresponds to output circuit saturation state, and when there is a pulse input, this output circuit will register a voltage of a certain value).

b. - The "Schmitt" trigger circuit (a circuit which works in a similar way to the monostable multivibrator, but with the difference that the "SchmitC trigger circuit maintains the voltage at a specific value, while the input activity lasts).

There are also a wide range of possible circuits consisting of operational amplifiers, flip-flops or digital trigger circuits, which have a similar effect. The optical pulse is thus changed into a square voltage wave, the length of which depends on the length of the activity. This pulse acts on block:

k 0 0 6 (3) The control circuit, which determines whether the motor receives direct power or not. In the case of direct power, the output potential can be obtained directly from the mains alternating current by applying the pulse to a potential element such as a thyristor, triac, GTO, or even a potential transistor which activates a relay control device to close the contact which activates the lift motor. A "Darlington" circuit may also be used to be able to increase the controllable potential. In any case, the purpose of this block (3) is to provide the power, the active current required to make this work, always doing this subject to the trigger circuit (that is to say, as long as this has a high voltage level at its output), which in turn depends on the ray of light (1) being interrupted.

In the case of direct action on a lift with memory, it will depend on the characteristics of the microprocessor, that is to say, on the voltage/current values which this requires to be activated. In this case block (3) of the control circuit could even be eliminated, and the potential (4) which acts on the lift motor circuit would be controlled by the microprocessor.

The system or circuit will be provided with a power source (5), with mains power input (6), preferably at 220 volts and 50 Hz. AC, and output through (7) in stabilised, controllable, short-circuitable DC output, in order to k 7 provide adequate polarisation in all the blocks in the system (1), (2) and (3), so as to establish its static work systems.

Having thus fully described each and every one of the parts which make up this automatic detector call device for lifts referred to herein, all that has to be stated is the possibility of manufacturing its diverse parts in a variety of materials, sizes and forms, and likewise, including suitable practical modifications to its construction, as long as they do not lead to alteration of the essential points of the purpose of this Patent application.

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Claims

CLAIMS:

1. An automatic call device for a lift and comprising a sensor responsive to the presence or absence of a lift caller, said sensor generating in use an output signal immediately a lift caller enters the field of action of the sensor; a delay unit responsive to an output signal from said sensor to retard said signal in use, and a trigger unit responsive to said signal and for controlling a lift motor.

2. A device according to claim 1 wherein said sensor is a passive infrared detector.

3. A device according to claim 1 wherein said sensor is a photocell.

4. A device according to claim 3 and further including a light source for said photocell.

5. A device according to any preceding claim wherein said trigger unit includes a rectangular voltage pulse generator.

6. A device according to claim 5 wherein said trigger unit includes a monostable multivibrator.

7. A device according to claim 5 wherein said trigger unit includes a Schmitt trigger circuit.

8. An automatic detector call device for lifts, wherein there is a light sensor block, which generates a ray of user-interceptible light based on the modulated emission of infra-red rays, or a photoconductive element, which is 1 1 9 activated when the internal semiconductor is lit by photons of energy not less than the threshold value of the semiconductor, generating a difference in potential the moment a person enters its field of action; a retarding or timing unit, intended to produce a delay in the time between the moment when it is activated by the sensor, and the moment when the potential reaches a trigger block; the trigger block receiving the pulses detected and provided by optical electronic attraction, and adapting them to give the characteristic voltage/current required to activate the lift motor.

9. An automatic call device for a lift substantially as described with reference to the accompanying drawings.

Published 1991 at The Patent Office. Concept House. Cardifr Road. Newport. Gwent NP9 I RH. Furlhercop'es.,na,,, be obtained frorn Sales Branch. Unit 6. Nine Mile Point. CA7nfelinfach. Cross Keys. Newport. NPI 7HZ. Printed by MultIPleX ehlq e' d. S% Mary Cray. Kent.