Patent GB-613234-A (GB)
Title: Control equipment for motor actuated electric switches
IPC: H01H3/26
Filed: 1946-06-12
Abstract: 613,234. Retarding action of switches. LANDIS & GYR SOC. ANON. June 12, 1946, No. 17667. Convention date, June 22, 1945. [Class 38 (v)] A motor-actuated switch is caused to be delayed in its closing action, when the supply is switched on to the driving motor. Fig. 1 shows the switch in the open position. The driving motor 11, 12, 13 is connected across the supply mains in series with an auxiliary switch whose contacts 25 are mounted on arms 23, 24 which bear on the teeth of a control pinion 21. The movable main contact 1 is mounted on a spring arm 2 actuated by a roller 3 running on a cam 4 which is rigidly connected to the control shaft 5. A pinion 9 meshes with a pinion 10 rigidly fixed to the spindle of the driving disc 11 and is free to rotate relatively to the shaft 5. A friction plate 6 rigidly fixed to the shaft 5 is pressed against the pinion 9 by a spring 8. A spring 14, one end of which is secured to a ring 15 fixed on the shaft 5 and the other end of which is secured to a pin 16 mounted on a bearing bracket of the shaft, returns the shaft to its off position when the motor supply fails. The pin 16 also serves as a stop to limit the return motion by bearing against the friction plate 6. A driver arm 7 rigidly fixed to the shaft 5, is engaged by a pallet lever 18 by means of a spring 17. The pallets engage a ratchet pinion 19 which is fixed on a shaft 20 carrying the control pinion 21 and a gear-wheel 22. A cam 26 freely turning on the shaft 20 is actuated therefrom by a gear-wheel 28 driven via a lay-shaft 30 and a pinion 29. The cam 26 on rotation, engages a lug 27 on the contact carrier 23, thus holding the auxiliary contacts 25 together, Fig. 3. In the off position the front pallet engages with the ratchet pinion 19 and only contact carrier 23 engages a tooth of the pinion 21, hence the contacts 25 close the driving circuit of the motor. The cam 26 is clear of the lug 27. If now the supply comes on, the motor commences to rotate, the pallet lever 18 swings across so that the rear pallet engages and advances the ratchet pinion 19 by one tooth. The contact carrier 23 slips over the top of its tooth and both members 23, 24 are brought on to the flank of the succeeding tooth and the contacts 25 separate, Fig. 2, and the motor circuit is broken without the contact 1 being closed. Spring 14 returns the shaft 5 to its original position. -- The front pallet now advances the ratchet pinion 19 by a further tooth, thus causing the contacts 25 to re-engage. This cycle of operations is continued until the cam 26 is rotated opposite to the lug 27 to hold the contacts 25 closed and enable the motor to close the contacts 1. The motor is arrested by the upper edge of the plate 6 engaging a further stop (not shown) on the bearing bracket. The period of transmission can be adjusted by varying the gear ratio 22, 29. The single cam 26 could be a multiple one to obviate the necessity of it turning through a complete revolution between each closing of the switch, and also to allow the period of transmission to be adjusted. For a fixed period of transmission, the cam 26 could be fixedly mounted on the shaft 20, or alternatively the control pinion 21 could also perform the duty of the cam by having no teeth cut in the part which is to close the auxiliary switch.