GB2122573A - Lift cage door status indication - Google Patents

Abstract

In a multi-deck underground cage (60) each door has a switch (18 to 24) fitted to it to provide a door-open or door-closed signal. The signals identify the respective door and are used to modulate an infrared carrier signal which is transmitted downwardly and reflected to a receiver (3). Information decoded from the carrier signal is displayed to indicate the status of each door at a location remote from the cage. <IMAGE>

Description

SPECIFICATION Cage door status indication This invention relates generally to a cage system in a mine or similar installation wherein the cage has a plurality of decks or levels, and more particularly to the indication of the status of a door on each of the decks of the cage.

When a multi-deck cage docks at a station in a shaft the doors at one or more decks of the cage may be opened or closed independently of the other doors. The onsetter, that is the person who transmits signals to the driver of the winding system, must be aware of the status of each door, in other words know whether it is open or closed, before he is in a position to signal the driver that the cage can be moved away from the station.

Modern cages can have at least four decks and in practice the situation is encountered that different decks can dock at different levels at the station. For example a four deck cage can dock at a four level station with each deck corresponding directly with one of the levels at the station or possibly with the bottom deck otherwise being aligned with the top, second or third level on the station.

Under these circumstances it is difficult for the onsetter at all times to be aware of the status of each door on the cage the more so when one bears in mind that persons on the cage or on one of the levels can operate the doors independently of advising the onsetter thereof and at any time.

The problem of keeping the onsetter informed of the status of each door is compounded by the fact that the cage is not generally connected directly to a power supply and thus there is no ready means available for powering some mechanism which makes the door status information available to the onsetter.

It is an object of the present invention to provide an improved method of providing door status information under the circumstances described.

The invention provides a method of providing information on the status of doors of a multi-deck cage which includes the steps of generating for each door a signal which identifies the door and its status, and transmitting the signals to a receiver remote from the cage.

The signals may be generated by interrogating means at each door which provides an indication of the status of the door. These means may be interrogated in succession, and cyclically.

The signals may be transmitted at any suitable frequency but preferably at a frequency in the infrared region.

The infrared transmission preferably is directed downwardly from the cage.

The transmitted signals may be reflected or otherwise directed upwardly to the receiver.

The status of each door may be indicated by means of a visual or audible enunciator responsive to the receiver.

The invention also provides apparatus for providing information of the status of doors of a multi-deck cage which comprises means for generating for each door a signal which identifies the door and its status, a receiver remote from the cage, and means for transmitting the signals to the receiver.

The transmitting means preferably operates in the infrared region.

The invention further extends to a system wherein the transmitting means is installed on the cage and so aligned that the infrared transmission is downwardly directed.

The system may include means for intercepting and directing the transmitted signal to the receiver. This means may include at least one reflector of a suitable material e.g. stainless steel.

The receiver may be aligned to receive upwardly directed signals.

The signal generating means may be re sponsive to switch means operable by each of the respective doors. Each of the signals may be uniquely coded to identify the respective door.

The invention is further described by way of example with reference to the accompanying drawings in which: Figure 1 schematically illustrates apparatus according to the invention, and Figure 2 illustrates the manner in which the apparatus of Fig. 1 is employed.

Fig. 1 illustrates apparatus according to the invention which includes a transmitter 10, a receiver unit 1 2 and a display unit 14.

The transmitter has four inputs collectively designated by the numeral 1 6 which are respectively responsive to switches 18, 20, 22 and 24 respectively. The inputs are connected to a scanner 26 which in turn is connected to a multi-channel infrared transmitter 28. The transmitting unit is selfcontained and is powered by means of a battery 30 located in a housing of the transmitter unit. The battery is normally a dry cell battery.

The receiving unit 1 2 is powered from a low voltage alternating supply line 32 and includes a power unit 34 to provide the required d.c. voltage for its operation. The receiver unit includes an infrared receiver 36 which is connected to a multi-channel decoder 38. The decoder in turn is connected to a hold circuit 40.

Output lines 42 from the hold circuit 40 are connected to display logic circuitry 44 in the display unit 14. The logic circuitry is powered by means of a power unit 46 connected to the a.c. supply line 32. The logic circuitry has output lines connected to red and green light emitting diode pairs 48, 50, 52 and 54, and a relay 56. The contacts of the relay are accessible at output terminals 58.

Fig. 2 illustrates a multi-deck cage 60 docked at an underground station 62. In this example the cage 60 has four decks 64, 66, 68 and 70 respectively and each deck has a separate and independently operable door.

In accordance with the invention the switches 1 8 to 24 are installed on the cage so that they are operable by the action of the doors on the decks 64 to 70 respectively. The transmitter unit 10 is installed on the cage near the roof of the upper deck 64 with the transmitter 28, see Fig. 1, being directed downwardly. The transmitter 10 has an output aperture 72, and this is covered and sealed by means of a window which is transparent to the infrared frequency emitted by the transmitter. In addition, as shown in Fig.

2, the window is directed into a tube 74 so that it is effectively mechanically shielded in all directions save from the underneath which is the general transmitting direction.

The receiving unit 1 2 and the display unit 14 are installed at the station 62 in the manner schematically illustrated. The receiving unit 1 2 with the receiver 36, see Fig. 1, is installed at a lower level at the station 62 and is directed downwardly. The receiving unit also has an infrared transparent window 76 and, as shown in Fig. 2, has a downwardly directed tube 78 shielding the window. The display unit 14 is installed at a suitable location on the station 62 where it is easily visible to the onsetter working at the station.

A stainless steel reflector 80 is positioned below the receiving unit 1 2.

Fig. 2 also illustrates, somewhat schematically, different levels 82 to 88 respectively of a gantry at which the cage docks.

The transmitter unit 28 is designed to emit sufficient power to ensure that the receiving unit 1 2 receives a signal of adequate strength when the cage is at the position shown in Fig.

2 and also when the lower most deck 70 is aligned with the level 82. It should be mentioned at this stage that the deck 70 can in practice be aligned with any one of the levels 82 to 88. In the first case the transmitter is at its furthest distance from the receiver. The transmitter is closest to the receiver when the deck 64 is aligned with the level 88.

The transmitter 74 is located on the cage near the side of the shaft where the receiver is installed. Thus it is at all times aligned more or less with the receiver in that its emitted infrared beam impinges on the reflector 80.

When the cage docks at the gantry with any of the decks of the cage being aligned with the different levels of the gantry the transmitter unit therefore transmits a beam of radiation at an infrared frequency which impinges on the reflector 80 and which is redirected into the receiver 1 2. The scanning unit 26 continuously and successively interrogates the switches 18 to 24 on a cyclical basis and obtains information from the switches indicating whether or not the respective doors are open or closed. Depending on the status of the door the scanning unit 26 generates an appropriate signal. For example if a door is closed the scanning unit generates a coded signal which uniquely identifies the door and if the door is open it does not generate the code. This is a fail-safe feature.The four signals or codes are multiplexed by the scanning unit and used to modulate the carrier or output signal of the transmitter 28. Thus the infrared transmitted signal which is directed to the reflector 80 conveys information which uniquely identifies the doors and indicates the status of each door.

The signal which impinges on the reflector 80 is directed upwardly into the receiver unit 1 2 where it is received by the receiver 36 and demodulated whereupon the demodulated signal is decoded in the decoding device 38.

Four signals which correspond to the input signals to the scanning unit are then applied to the hold circuit 40 which provides on its output lines 42 steady signals indicative of the status of the doors. Since each of the lines 42 corresponds to one of the switches 1 8 to 24 and hence to one of the doors on the decks 64 to 70 the doors are uniquely identified as well.

The signals on the lines 42 are applied to the logic circuitry 44 and depending on the status of a door the diode pairs 48 to 54 are appropriately energized. For example if the door on deck 64 is open the corresponding red diode in the pair 48 is energized whereas if the door is closed the green diode in the indicated pair is energized. A similar situation prevails in respect to the other diode pairs 50 to 54 with regard to the doors on the other decks.

When all of the doors are closed the logic circuitry 44 additionally provides a signal which energizes the relay 56 and this provides a closed contact via the terminals 58 which is connected to an interlock circuit. This contact for example ensures that the brakes cannot be released by the driver of the winder until such time as all the doors of the cage are closed. If any of the doors are opened the relay 56 is de-energized and the interlock circuitry is disabled.

It should be pointed out that the transmitter 10 and the receiver 1 2 are installed directed downwardly to ensure that minimal dirt collects on the windows 72 and 76 respectively, that they are well protected against objects falling down the shaft, and thus that the efficiency of the system is maintained. The reflector 80 is located close to the receiver and this carries with it the advantage that even when dust or other foreign matter settles on the reflector there is a scattering of the received infrared signal by the foreign matter, apart from the residual direct reflection by the reflector 80, which causes the signal to be redirected into the receiver.Since the transmitter and receiver are directed downwardly with their windows on the undersides it is possible to make the units water and dustproof and to ensure that they are adequately able to withstand mechanical shocks.

Particular advantages arise from the use of an infrared transmitting signal. It is found that the infrared transmitter consumes very little power and thus can be powered by means of an onboard battery 30 for a considerable period of time. Secondly the signal, at an infrared frequency is, as has been pointed out, not unduly adversely affected by the presence of dirt or foreign matter between the transmitter and receiver, for example on the reflector surface. The signal is also not susceptible to electromagnetic interference.

Another point is that the emitted infrared beam is not highly directional and thus impinges on the reflector irrespective of the position of the cage when it is docked at the station 62. With regard to this last mentioned point it should be mentioned that the correct physical siting of the transmitter and receiver greatly assists in ensuring that an adequate signal is received by the unit 1 2.

The number of channels used in the apparatus of the invention is determined by the number of doors to be monitored. Additional channels may however be used for transmitting other data e.g. the status of the battery 30 in the transmitting unit 10.

Claims (22)

1. A method of providing information on the status of doors of a multi-deck cage which includes the steps of generating for each door a signal which identifies the door and its status, and transmitting the signals to a receiver remote from the cage.

2. A method according to claim 1 wherein the signals are generated by interrogating means at each door which provides an indication of the status of the door.

3. A method according to claim 2 in which the said means are interrogated in succession.

4. A method according to any one of claims 1 to 3 in which the signals are transmitted at a frequency in the infrared region.

5. A method according to any one of claims 1 to 4 in which the signals are transmitted downwardly from the cage.

6. A method according to claim 5 which includes the step of directing the downwardly transmitted signals upwardly to the receiver.

7. A method according to any one of claims 1 to 6 which includes the step of indicating the status of each door by means of a suitable enunciator.

8. A method of providing information on the status of doors of a multi-deck cage which includes the steps of generating for each door a signal which identifies the door, and transmitting the signal to a receiver if the door is closed.

9. A method of providing information on the status of doors of a multi-deck cage which includes the steps of generating for each door a first signal which identifies the door and its status, modulating a carrier signal with the first signals, transmitting the carrier to a receiver, demodulating the carrier to derive for each door a second signal which corresponds to the respective first signal, and applying the second signals to an enunciator to indicate the status of each door.

10. A method according to claim 9 in which the carrier signal is in the infrared region.

11. A method of providing information on the status of doors of a multi-deck cage substantially as hereinbefore described with reference to the accompanying drawings.

1 2. Apparatus for providing information on the status of doors of a multi-deck cage which comprises means for generating for each door a signal which identifies the door and its status, a receiver remote from the cage, and means for transmitting the signals to the receiver.

1 3. Apparatus according to claim 1 2 in which the transmitting means operates in the infrared region.

14. Apparatus according to claim 1 2 or 1 3 in which the transmitting means generates a carrier signal and the said signals are used to modulate the carrier signal.

1 5. Apparatus according to any one of claims 1 2 to 14 which includes means for intercepting and directing the transmitted signal to the receiver.

1 6. Apparatus according to claim 1 5 in which the intercepting and directing means includes at least one reflector.

17. Apparatus according to any one of claims 1 2 to 1 6 in which the transmitting means is so aligned that the transmitted signal is directed downwardly.

1 8. Apparatus according to any one of claims 1 2 to 1 7 wherein the signal generating means is responsive to switch means operable by each of the respective doors.

1 9. A system which includes a multi-deck cage with a plurality of doors, a plurality of switches which are operable by the respective doors, a transmitter which transmits data, generated by means of the respective switches, on each door if the door is closed, and a receiver which receives the transmitted data.

20. A system which includes a multi-deck cage with a plurality of doors, a plurality of switches which are operable by the respective doors, a transmitter with a carrier in the infrared region which is modulated with data generated by the switches, a receiver which receives the transmitted carrier, and means responsive to the receiver for indicating the status of each of the doors.

21. A system according to claim 20 which includes a reflector arranged to reflect the transmitted carrier to the receiver.

22. Apparatus for providing information on the status of doors of a multi-deck cage substantially as hereinbefore described with reference to the accompanying drawings.