Patent GB-168962-A (GB)
Title: Improvements in mine signalling systems
IPC: B66B19/06
Filed: 1920-06-02
Abstract: 168,962. Sterling Telephone & Electric Co., Ltd., and Davey, W. C. June 2, 1920. Mine signalling systems; order apparatus.- In systems in which a cancelling switch is operated from the engine, action signals alone are cancelled by the engine starting. Two arrangements are described in which non-action signals can be set up while the engine is running; in one, circuits are provided for such signals in parallel with the circuit of the cancelling switch and in the other this switch operates only on completion of a signal and is put out of action if the signal is cancelled. The latter arrangement can be used with the sending arrangement described in Specification 13062/14. The switch itself is shown diagrammatically in elevation in Figs. 6 and 8, and in plan and elevation in Figs.. 5 and 3 respectively. In action, the enginedriven cam 8 depresses the lever 14 by contacting with the roller 15 and breaks contact at the springs 7, but this action cannot take place till the electromagnet 18 is energized when the attracted pivotal member 16 brings the roller into the path of the cam. The device is first described in connection with a system substantially that set out in Specification 112,497, Fig. 6, showing the banksman's signals, the arrangement for the onsetters being similar, but further relays allow any one onsetter to monopolize transmission. The sending key OK is connected to positive, and on a first impulse being sent by tapping on contact 1 the relays NR, R1, and R2 are directly energized, while the fourth armature of the relay NR completes a circuit-positive, fourth armature of relays NR, winding of relay BKR, cancelling switch 7 to negative for. the relay BKR which locks up over its first armature and prepares a circuit for the relay R4. If the key is now dropped on to contact 2, the relay XR is energized, completing circuit at its first armature for the relay R4, the excitation of these two relays lighting the signal R through second armature of relay XR, third armature of relay R4, second armature of end relay FR, second arma. tures of relays LR12 - - LR2, and third armature of relay XR to negative. On a fresh signal being sent the circuit of relay XR is broken so that the signal R is cancelled, while starting of the engine acts in the same way, since operation of the cancelling switch breaks the circuit for the relay BKR and therefore for the relay R4. It will be seen that as the action signal relays LR2, LR4 alone are connected direct to the cancelling switch, their circuits alone are directly affected by its action. The circuit for the electromagnet is as follows:- from contact 2 to second armature of relay XR, to first armature of relay FR, through the third (left-hand) armatures of relays LR12 - - LR6, second armature of relay R4, and winding 18 to negative. It is clear therefore that for non-action signals (i.e. those from relays LR6 - - LR12), the excitation of the appropriate relay prevents completion of the electromagnet circuit and therefore operation of the cancelling switch. Figs. 8 and 10 illustrate a modification in which dial signals are employed with a resetting-magnet BRM, which acts to cancel a signal on excitation but can only be energized when both relays 32 and 33 are quiescent. Relay 32 is only excited while a message is being sent, and relay 33 is energized when the key OK is dropped on to contact 2, i.e. after a message has been sent. This relay 33 locks up over one of its own armatures and also over the last armature of relay 34 so long as' relay 34 is not energized, which it is however if the indicator is left on an action signal on the dial. In this case, relay 33 depends on its own locking- up circuit which includes the switch 7, so that starting the engine breaks this circuit, and the armatures of relay 33 fall back, as relay 32 is already de-energized, and the resetting magnet operates. In the case of a non-action signal, the circuit of relay 34 is not completed, so that the relay 33 remains locked up over the last armature of relay 34 and starting of the engine does not produce cancellation. Specification 18661/14 also is referred to.