Patent GB-812048-A (GB)
Title: Improvements in or relating to receivers for electric remote-control systems
IPC: H02J13/00
Filed: 1958-01-17
Abstract: 812,048. Electric selective signalling. COM PAGNIE POUR LA FABRICATION DES COMPTEURS ET MATERIEL D'USINES A GAZ. Jan. 17, 1958 [Jan. 17, 1957], No. 1709/58. Class 40 (1). [Also in Group XXXVII] The invention relates to a remote control system wherein a control function is selected by the time interval between two pulses of predetermined frequency. The " start " pulse through relay sensitive to the signalling frequency, starts a synchronous motor 1 which drives a control shaft 3 through one revolution, and the " execution " pulse, provided its timing is correct, permits an arm or cam 33 on the control shaft to operate control switches, e.g. through a lever 34. According to the in vention, the frequency sensitive relay (not shown) has a resonant oscillating blade 51 which drives the planet member 58 of a differential 57 in the direction F<SP>1</SP> through a pawl 52, ratchet wheel 53 and universal joint 55. Normally, with the various elements in the positions shown, the sun wheel 59 is locked by a pawl 61. The planet member 58 therefore drives the sun wheel 62 which rotates a vane 65 in the same direction F<SP>1</SP>, until it rocks a pin 66 to release a lever 70. The lever 70 then permits a stirrup 20 to rock in the direction of arrow F<SP>2</SP> under the bias of a spring 22. The stirrup, through its insulating roller 23, closes the circuit of motor 1 at contacts 29, and these contacts are held closed in the " off normal " position of the control shaft 3 by a roller 8 actuated by a cam 31. The stirrup 20 also brings the lever 34 into the path of the control arm 33, and through various links 5, 11, 13, 14 rocks a pin 16 to release the locking pawl 61. This frees the sun wheel 59, whereupon a biasing spring 63 returns the sun wheel 62 and hence the vane 65 to normal position. The link 5 carries a pin 4 spring- biased at 7 into engagement with a toothed wheel 30 on the control shaft 3. Normally, this pin 4 engages the top of a tooth on the wheel 30 but drops into the notch next to this tooth as the cam 30 ismoved by the motor. This permits the stirrup 20 to return to its normal position, under spring bias (not shown), where it is again held by the lever 70 and locking pin 70. The sun wheel 59, however, is not locked by the pawl 61 until the pin 4 engages the top of the next tooth of the wheel 30. The time interval between a " start " pulse and an " execution " pulse is made different from the time interval between successive execution pulses or any integral multiple thereof, to preclude effective operation of the receiver by a second pulse if the first pulse received is an execution pulse rather than a starting pulse. In such a case the following pulse will arrive when the pin 4 lies in a notch in the wheel 30 so that the stepping of the ratchet wheel 53 by the received pulse has no effect on the sun wheel 62 and vane 65. If, however, the motor 1 is started by a " start " pulse, a following " execution " pulse will arrive when the pin 4 engages the top of a tooth on the wheel 30 so that the sun wheel 59 is locked by the pawl 61. Consequently the stirrup will be rocked as previously explained to bring the lever 34 into the path of the arm 33 which, provided the timing of the two pulses is appropriate to the receiver will rock the lever 34 relative to its shaft 21 to effect the desired switching operation.