Patent GB-642479-A (GB)
Title: An improved receiving device for electric switching operations in remote control installations
IPC: H02J13/00
Filed: 1948-03-03
Abstract: 642,479. Actuation of switches. LANDIS & GYR SOC. ANON. March 3, 1948, No. 6721. Convention date, March 10, 1947. [Class 38(v)] A selector switch or "receiver" for a remote control installation has a relay which on the receipt of a first or " starting" audio-frequency impulse starts a synchronous motor, which then drives a control shaft through one revolution; if whilst the shaft is turning, a second or " group " impulse is received by the relay at the appropriate time, the receiver is rendered effective to operate a selected switch unit if a third or " control " impulse is received by the relay at an appropriate time; but if the second or group impulse is not received at the correct time, then the receiver is locked against operation by any subsequent impulse. The audio-frequency starting impulse superimposed on the lines a, b, momentarily energizes relay coil 2 to turn the relay armature 3, which by means of a cam 5 closes contacts 7, 8, to energize the synchronous motor 12. The motor then drives a control shaft 13 through one revolution, the contacts 7, 8 being held closed until the end of the revolution by a cam disc 15. During the initial part of the revolution a cam 40 on the adjustable " group control " plate 19 engages the end 41 of a lever 42 and causes the lever to tilt on its spring blade, mounting 43. The end 44 of the lever 42 is thus moved from the rear to the front of a pivoted release bar 9. the bar being lifted by the inclined -edge 45 of the lever and then allowed to drop again. When the cam 40 moves out of engagement with the end 41 of the lever, the end 44 is moved back into abutting engagement with a projection 46 to lock the release bar 9, unless the second or group impulse is received by the relay. In this event the bar 9 is lifted by the cam 6, so that the end 44 of the bar 42 may pass underneath the bar 9, so that the bar 9 is left free for subsequent operations. The third or " control " impulse is timed so that it is applied to the relay at the instant when a notch 20 or 21 of a disc 17 or 18 has been moved by the rotation of the shaft 13 to a position over a projection 22 or 23 of a lever 24 or 25 mounted on a blade spring 26 or 27. If in the Fig, the relay is energized when the notch 21 is over the projection 23, the projection enters the notch under the bias of the blade spring 27 as the release bar 9 is moved by the relay out of the path of the end of the lever 25. Thus a projection 29 on the spring 27 is moved out of engagement with a cam 31, and a spring 34 which has been tensioned by the motor turns a unit of which this cam forms a part, until a cam 30 engages a projection 28 on the other blade spring 26. The cam 32 of this unit opens contacts 33 to perform the selected switching operation. If required, a further impulse applied to the relay when the notch 20 is over the projection 22 results in the reclosing of the contacts 33. Additional discs 17, 18, levers 24, 25, cam units 30-32 and springs 34 may be provided to control additional switches 33 in response to additional " control " impulses. In a modification (Figs. 4 to 7, not shown), the receiver is arranged so that additional group control plates and levers may be provided to enable the device to operate switch units in response to impulse. In this case each group control lever (as 42) does not lock the bar 9 but controls the latching of the levers 24, 25 of the associated switching arrangement by separate latching levers, so that one part of the device may be operative whilst another part is inoperative.