Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF _ E INVENrION
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 s~ation 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
- - 1-5 - 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 o~ advtsing 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
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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.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved
method o-F providing door status information under the circumstances
described.
The invention provides a method of providing information on the
status of doorsof 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
o from the cage.
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The transrnitted siynals 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.
- lO ~ -~ 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 ~o 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 responsive to switch means
operab'e by each of the respective doors. Each of the signals
may be uniquely coded to identify the respective door.
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BRIEF DESCRIPTION OF ~IE DRAWINGS
,
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
Figure 1 is employed.
DESCRIPTION OF PREFERRED EMBODIMENT
Figure 1 illustrates apparatus according to the invention which
includes a transmitter 10, a receiving unit 12 and a display unit
14.
The transmitter has four inputs collectively designated by the
numeral 16 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 self-contained and is powered hy
means of a battery 30 located in a housing of the transmitter unit.
The battery is normally a dry cell battery.
The receiving unit 12 is powered from a low voltage alternating
supply line 32 and includes a power unlt 34 to provide the
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requlrecl d.c. voltaye for its operation. The receiver unit
includes an inFrared receiver 36 which is connected to a mul-ti-
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, 509 52 and 54, and a relay
56. The contacts of the relay are accessible at output terminals
58.
~ Figure 2 illustrates a multi-deck cage 60 docked at an underground
station ~2. In this example the cage 60 has four decks 64, 66, 68
and 70 respectively and each deck has a separate and independently
operabie door.
In accordance with the invention the switches 18 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 F;gure 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 Figure 2, the window is
- directed into a tube 74 so that it is effectively mechanically shielded
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in all clirections save from t:he underneath which is the general
transmitting direction.
The receiving unit 12 and the display unit 14 are installed at
the station 62 in the manner schematically illustrated. The
receiving unit 12 with the receiver 36, see Figure 1, is installed
at a lower level at the station 62 and is directed downardly.
The receiving unit also has an infrared transparent window 76 and, as
shown in Figure 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 B0 is positioned below the receiving
unit 12.
Figure 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 12 receives a signal of adequate
strength when the cage is at the position shown in Figure 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
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receiver. The transmitter is clos~stto -the receiver when the deck
fi4 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 lZ. 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 ~r
codes are multiplexed by the scanning unit and used to modulate thecarrier
or output signal of the transm~tter 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 12 where it is received by the receiver 36 and
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demodulated whereupon -the demodula-ted siynal 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 18 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 of 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_cl~sed. -If any--of--the- -
doors are opened the relay 56 is de-energized and the interlock
circuitry is disabled.
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It should be pointecl out that the transmitter 10 and the receiver 12
, are 1nstalled directed downwardly to ensure that minimal dirt,collects
on the windows 72 and 76 respect-ively..that they are well protected
against objects falling down the shaft, and thus that the efficiency of
S 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 rèFlector 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 advantagesarise from the use of an in-Frared 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 ar,d
receiver, for example on the reflector surface. The signal is also
not suscept~lble to electromagnetic interference. Another point
is-that-~the---emitted~~~nf~are-d-bea~-is--not-highly di-rectiona-l---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
2~ 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 12.
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.
