Patent GB-386007-A (GB)
Title: Improvements in or relating to electromagnetic switches particularly for use in connection with the distant control of electric circuits
IPC: H01H50/32
Filed: 1931-07-08
Abstract: 386,007. Switching systems. JOHNSON & PHILLIPS, Ltd., Charlton, London, and McGADIE, J., 37, Clouston Street, Glasgow. July 8, 1931, No. 27538/32. Divided on 385,996. [Class 38 (iv).] An electromagnetic switch for use in train-lighting control systems which is of the type which is closed and opened after alternate successive momentary energizations of the controlling electromagnet comprises as shown in Fig. 1 a core 5 operated by a solenoid 6 to control movable bridging contacts 1. A pivoted arm 14 extends through a slot formed in the member 12 attached to the core the arm 14 having pins 16 extending into slots 17 formed in the member 12 at each side of the slot. The free end of the lever 14 carries a pivoted latching detent 18 or parallelogram formation co-operating with a shaped locking plate 19. When the electromagnet 6 is energized the plate 18 is moved into the position 18a so that on de-energization the plate 18 is rotated through approximately 180‹ by its lower side first striking a corner v and an adjacent longer side striking the outer termination of a horizontal portion z of the fixed plate the detent finally reaching a position shown at 18b and the contacts 1 being moved to bridge the fixed contacts 2. On a subsequent energization of the electromagnet the detent is moved into the position shown at 18c with its upper end between two inclined surfaces t, w so that on de-energization the lower end of the detent is retained by the horizontal face z of the plate 19 and the parts are returned to their original position. Mounted on the same baseplate 20 is a second electromagnetic switch the fixed contacts 4 of which are bridged by a member 3 carried by the core 7, the return movement of which may be retarded by a dashpot 9. The electromagnets 6, 8 are adapted to be energized simultaneously. The circuit or arrangement of a number of such switch combinations- 81, S2, S3 and S4-in a train lighting system are shown in Fig. 7 the parallel connected coils 6, 8 of the combination S1 being completed from a central control switch CS through a pilot wire p<1> and neutral return wire N. The operation of the combination S1 completes a lighting circuit C1 and at the same time by bridging contacts 4 causes the operation of the combination S2 which completes its own lighting circuit and initiates the operation of the combination S3 and so on until all the circuits are completed. The retarded return of the contact 3 ensures that the operation of the succeeding relay combination takes place, the controlled contacts 2 being bridged and disconnected by successive operations of the control switch in the manner previously described. In a modified construction, Figs. 3 and 4 (not shown), the separate relay provided for controlling the contact 3 is dispensed with, this contact being attached to or operated by the core 5. In the latter case the contact 3 may be raised into contact by the upward movement of the core or and may be arranged to be spring returned under the control of a dashpot. Operating knobs 29, 30 may be attached to the upper ends of the solenoid cores to permit of their optional manual operation.