GB2149546A - Indicator apparatus - Google Patents

Abstract

An indicator apparatus for indicating the position of a lift car in a shaft which may be applied as original equipment to a new lift or may be applied retrospectively to an old lift. The data relating to the position of the lift car is provided by a central control unit passed up wires to each floor in the form of a serial pulse train having a start (or end) bit and a plurality of segment bits which specify directly whether respective segments of the display are to be illuminated. <IMAGE>

Description

SPECIFICATION Indicator apparatus The present invention relates to indicator apparatus for use with lifts.

As is well known, many lifts incorporate an indicator system in which at each floor there is an indicator which indicates the position of the lift car.

Such indicators conventionally require complex apparatus to control them. In particular the apparatus on each floor has a separate indicator for indicating the floor which the lift car is adjacent, and conventionally there is provided at least one wire for each floor. Thus if there are sixteen floors there would generally be seventeen wires, that is one wire for each floor and an earth return. Thus if the car is adjacent floor 2 then the indicators on all of the floors which indicate 2 will be illuminated and the remaining indicators will not be illuminated.

However, there are many older lifts which do not carry such indicators and in some cases modern lifts do not carry such indicators to save cost. It has been found however that such an omission is in fact costly because it increases the frustration and hence vandalism by users of the lift.

The present invention provides an indicator apparatus for indicating the position of a lift car in a shaft which may be applied as original equipment to a new lift or may be applied retrospectively to an old lift. The apparatus is simple but effective.

It is desirable, particularly when fitting such apparatus restrospectively to an old lift that the wiring of the apparatus be kept as simple as possible.

One way of overcoming the problem of 17 wires for 16 floors would be to have an electronic logic element at each floor and to pass a coded signal along a common wire, the electronic logic element decoding the signal and producing the necessary indication.

Various electronic indicator apparatus have been proposed for this purpose but they usually involve sending signals which are coded for example to carry the binary number of the floor to be indicated and a local microprocessor or system is required in each floor to decode the signal. However, in a lift shaft environment the space on each floor for the display apparatus to be installed is very limited indeed and also, particularly in the situation where the equipment is being applied retrorespectively, the cost of the local logic circuits is an important factor. If the decoder requires (as is usually the case) large integrated circuits, there are difficulties because it is difficult to fit them into the lift indicator apparatus and they are relatively expensive items.

The present invention provides, according to one aspect, lift car position indicator apparatus comprising means forming part of or connectable to the lift control mechanism, said means being adapted to pass a single signal along signal wire to an indicator on one or more floors, said indicator comprising a series of segments which are selectively illuminated or otherwise arranged to change appearance so as to make up a number of character which will form the desired indication, said signal indicating the floor adjacent which the lift car is situated and comprising a series of discrete signals, one of which indicates the beginning or end of a series, and the others of which indicate directly which segments are to be illuminated.Thus for example if the indicator apparatus comprises an indicator to indicate two separate numbers (which would cover the situation up to 99 floors) then conventionally each of the two characters would be made up of seven segments and so the signal would comprise 15 separate signal bits comprising a start signal and 14 separate one signal bits each indicating whether a respective one of the segments should be illuminated or not.

In one arrangement the signal may also include a power signal for operating both the local logic and the indicator in which case two wires may be used. In another arrangement there may be provided further wires, one providing an earth return and the second providing a wire along which the power to drive the indicator is passed separately from the signal. In a particularly preferred arrangement of this second aspect there may be provided a fourth wire which carries a clock signal.

The indicator itself preferably comprises a light emitting diode numeric display or a liquid crystal numeric display. There may also be provided means for causing repetitive variation of the display to indicate that a lift car is moving.

The local logic on each floor may comprise a simple shift register which may be initiated by a start signal, may then store the fourteen bits of information in the register and then pass them out along fourteen parallel lines to switch the fourteen segments of the indicator display.

Such an arrangement is considerably cheaper and more compact that that previously proposed in that it simply requires a shift register and latch.

Preferred embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is a block circuit diagram of the part of an indicator apparatus according to the invention provided at each floor, Figure 2 is a block diagram of the part of the apparatus of the invention comprising the system controller connectable to the lift control circuit, and, Figure 3 is a block diagram similar to Figures 1 and 2 in combination showing a second embodiment of the invention.

Referring firstly to Figure 2 the system controller 10 which may be mounted in the lift control room includes thirty parallel inputs 11 in three bundles 11A, 11B, 11C of ten each connected to receive signals from the lift control apparatus relating to which floor (up to a maximum of thirty floors) the lift car is adjacent. There is a second two-wire input 12 for receiving signals from the lift control apparatus indicating that the lift car is in motion (ie the brake is off). The inputs 11 and 12 may be optionally connected to a rectifier attenuator 13. This attenuator 13 receives power via a line 14 from a local (power supply unit) PSU 16 which receives a 240 volt input along line 17.

The inputs 11 and 12 are thus connected optionally via the attenuator 13 to a central processing unit 18 which may include a memory in the form of a EPROM. The CPU 18 has a power supply via line 21 from the local PSU 16.

Provision is made for the inclusion of a second output PSU, and a passive rectifier/attenuator input adaptor to permit multiple outputs where more than one lift car is being controlled and high voltage A/C inputs respectively.

An output from the CPU 18 is passed along line 22 to an output PSU 23 which produces an output signal across lines 26, 27. A second output may be provided to a line 28, output PSU, and output lines 31, 32.

The mode of operation of the system controller 10 will now be described. Assuming that the input lines 11 deal with thirty floors, and the CPU 18 has ten input lines and therefore the thirty floors are divided into three sets of ten floors by bundles 11A, 11B, 11C. Thus, for example, if the lift is on floors 0 to 9, then a corresponding signal will appear on one of the input lines 11A, if the lift car is at floor 10-19 the signal would appear on one of the lines 11 B, and if the lift car is at floor 20 to 30 the signal would appear on one of the input lines 11C. Clearly any arbitrary division of the signal can be provided.

The central processor 18 sequentially samples from each of the three bundles of lines 11A, 11B, 11C and scans its own input lines and as a result will receive an input signal unique to a particular floor. The CPU 18 is programmed to provide a pulse width modulated signal unique to that floor on line 22 to the output PSU 23. This pulse width modulated signal (which we shall call the data signal) is then impressed on the DC output voltage on the lines 26, 27. Thus the signal between lines 26, 27 comprises two components, a DC power supply voltage (12 volts) and a pulse width modulated data signal. In practice, the data signal comprises a fourteen bit signal with a unique combination of bits for each floor. There is also an extra start bit.

The arrangement of the bits will be described later.

In addition to this, if the lift car is in motion as is indicated by an input signal on inputs 12 then the CPU will switch the output lines 26, 27 on and off at a rate of 2 Hz or alternatively sends a string of zero pulses at 2 Hz intervals which has the same effect.

In addition to the (hard wired) input lines 11 a micro-processor interface 20 is provided serving the dual function of permitting controllers to be cascaded if more than thirty floor signals are required or, of mapping the controller 10 into a host MPU system's port structure on MPU controlled lifts.

The lines 26, 27 may be provided by a simple two core cable which is passed up the building, conveniently through the lift shaft to connect with a display module 40 on each floor. Each display module 40 comprises a generally conventional numeric display 41 comprising two seven segment displays which may be provided either by light emitting diodes or liquid crystal display driven by a conventional driver 42 from a latch 43, the latch receiving signals from a shift register 44. The lines 26, 27 are connected in parallel with each display module 40 and in particular with a polarity corrector 46 comprising a bridge rectifier which provides an output on lines 47, 48 of the correct polarity no matter which way round the lines 26, 27 are connected to the corrector 46. Thus the output lines 47, 48 car provide power to drive the display module 40.

The voltage controller 49 produces a stable 9 volt DC supply to various components within the display module 40, a current limited supply to the segments of the numeric display 41 and a variable voltage to the driver 42 (which may be varied by means of a preset resistor to determine the intensity or brightness of the display 41). The data signal is stripped by means of the detector 51 and this data signal is passed to a multi-vibrator 52.

The data signal is also passed to a gate 53 which operates 1 when the leading edge of a pulse reaches it to provide a clock pulse to operate the shift register 44. The binary data signal which is unique for each floor is passed from the multi-vibrator 52 via the gate 54 into the shift register 44.

As already mentioned the leading front edge of the data signals are used to produce clock signals on the clock 53.

The data signal regarding the particular floor number to be displayed is in the form of a binary signal (ie a "0" or "1" bit) of fourteen bits with a start bit. Each one of the fourteen bits in the signal relate to a single one of the fourteen segments in the display 41. Thus each of the fourteen bits may be "0" or "1" and it may be arranged such that if the bit is "1" then the particular segment is illuminated and if it is "0" then it is not illuminated.

Thus when the data is loaded into the shift register and the start bit reaches the end of the shift register 44 (at which time the shift register has the complete coded signal within it) the start signal causes the latch 43 to operate so that the information from the shift register 44 is passed to latch 43 and to the driver 42. Of course there are fourteen parallel lines between the shift register 44, the latch 43 and the driver 42, one line relating to each segment in the display 41. The driver 42 thereafter operates the display 41 by illuminating those segments for which the corresponding part of the signal had a signal of "1" to produce the correct numeric display. The shift register is then filled once again with the next incoming binary signal.

It will be understood therefore that although we refer to the signal as a binary signal it is binary in the sense of having bits of "0" and "1" but is not encoded in the form of conventional binary arithmetic.

To ensure that the shift register is kept in register with the data signals, at regular intervals a data signal comprising a series of zeros is passed by the CPU 18 along the lines 26, 27 and this clears the shift register 44 so that the next start signal (which will be a logic 1 signal) followed by the relevant data signal, will be inserted into the shift register and when the start logic 1 signal reaches the end of the shift register 44 it is caused to operate to pass the information, as above described, to the latch 43.

Furthermore, as already described, the signal, that the data signal and DC signal on lines 26, 27 is switched on and off or a string of zero pulses is sent at regular intervals at a rate of 2 Hz so that all of the segments are regularly turned off (ie the numeric display 41 flashes) if the lift car is in motion, that is, whilst suitable signals are received on input 12.

A second embodiment of the invention is illustrated in Figure 3. Similar reference numerals have been used to denote similar parts to those in Figures 1 and 2.

In this second embodiment four wires 61, 62, 63, 64 pass up the lift shaft. The power supply to drive the numeric display 41 is passed from a display PSU 60 to the line 63 with an earth return 64. In this present instance the data signals which are used to control the operation of the numeric display 41 are separated and passed to the system controller 10 on line 62 and the clock pulses which in the previous embodiment are produced by a clock generator within the display module 40 are produced by the controller 10 and passed along the line 61. Thus at each display module 40 there is provided a clock signal clamping apparatus 68 connected to line 61 and a data signal clamping apparatus 67 connected to line 62.

The four lines 61 to 64 are screened by a suitable earthed screen 66.

The operation of the apparatus of Figure 3 is different from that of Figures 1 and 2 in that the data and power supply have been separated on separate lines as has the clock signal. However, although the display module 40 be operated in the same way as the display module 40 of Figure 1 the provision of four wires and the separation of function allows for a different form of operation if desired. The data pulses passed on line 62 are arranged so as to be at a high frequency (and hence the need for the screened earth 66) and because a high frequency is used the numeric display 41 (which has a total of 2 x 7 segments) may be driven so that each required segment is separately switched on in sequence rather than simultaneously.Thus if the figure "7" is to be indicated then it may be arranged that, in sequence, the upper of the eight segments of the numeric display 41 is displayed first followed by the upper right hand segment followed by the lower right hand segment. Thus only one segment would be energised at any one time but of course if the frequency repetition is sufficiently great the human eye will see all three segments operated at the same time. This reduces the power requirement and hence allows thinner power lines 63, 64 to be used or more floors to be operated from the same thickness lines 63, 64.

As with the arrangement of Figures 1 and 2 there is a second output 69 comprising, as with the other output, four lines.

There has thus been described two simple systems which may be either original equipment or applied to already existing lifts in which a single display will indicate the floor which the lift car is adjacent at any one time. In physical form he display module 40 30 may be of small dimensions and in a preferred form comprises a cylinder the front face of which carries a numeric display 41 and which may be simply inserted in a small hole in the wall adjacent the lift on each floor. The only wires passing up the inside of the lift shaft is a single two core wire in the first embodiment and four core wire in the second embodiment and the remainder of the apparatus, the system controller, may be provided in the lift control room.

Claims (9)

1. Lift car position indicator apparatus comprising means forming part of or connectable to the lift control mechanism, said means being adapted to pass a single signal along signal wire to an indicator on one or more floors, said indicator comprising a series of segments which are selectively illuminated or otherwise arranged to change appearance so as to make up a number of character which will form the desired indication, said signal indicating the floor adjacent which the lift car is situated and comprising a series of discrete signal elements, one of which indicates the beginning or end of a series, and the other of which indicate directly which segments are to be illuminated.

2. Apparatus as claimed in claim 1 in which the further signal also includes a power signal for operating both the local logic and the indicator in which case two signal wires are used.

3. Apparatus as claimed in claim 1 in which there are provided further wires, one providing an earth return and the second providing a wire along which the power to drive the indicator is passed separately from the signal.

4. Apparatus as claimed in claim 3 in which there is provided a fourth wire which carries a clock signal.

5. Apparatus as claimed in any of claims 1 to 4 in which the indicator comprises a light emitting diode numeric display.

6. Apparatus as claimed in any of claims 1 to 4 in which the indicator comprises a liquid crystal numeric display.

7. Apparatus as claimed in any of claims 1 to 6 in which there is provided means for causing repetitive variation of the display to indicate that a lift car is moving.

8. Apparatus as claimed in any of claims 1 to 7 in which the apparatus adjacent each indicator for controlling said indicator comprises a shift register which stores the bits of information in the register and then passes corresponding signals along parallel lines to switch the segments of the indicator display.

9. Apparatus as claimed in claim 1 substantiaily as herein before described with reference to Figures 1 and 2 or Figure 3 of the drawings.