Patent GB-290735-A (GB)
Title: Interlocking arrangements between circuit-breakers and other switches
IPC: H01H9/26
Filed: 1927-02-19
Abstract: 290,735. British Thomson-Houston Co., Ltd., Joyce, A. G. E., and Trencham, H. Feb. 19, 1927. Switches, interlocking; switchboards. -- An interlocking device prevents operation of auxiliary switches when a main switch is in a predetermined position and is rendered ineffective only when a second main switch is in a predetermined position. The drawings show such an interlock, comprising handles 8, 9 for operating selector switches 12, 13 to interconnect a feeder 14, through a circuit-breaker 15, selectively with one of a pair of bus-bars 16, 16<1>, which can be interconnected directly by the buscoupler 17. Keys are normally trapped in locks on the breaker 15 and coupler 17, and when the breaker is locked " off," and the coupler is locked " on," the keys can be withdrawn and inserted into the locks 18, 19 respectively. Rotation of the keys in locks 18, 19, removes the wedge-shaped heads 25, 25<1> of the bolts 23, 24 from the rollers 26, 26<1>, and allows the part 31<1> of the pivoted and weighted yoke 31 to withdraw from slots 33 or 33<1> on discs 34, 35 integral with the handles 8, 9. The bolt 24 of the lock 19 is forked at 39 to accommodate the pin 40 on the escapement ramp 41 pivoted at 42. A cam groove 43 on the member 41 co-operates with a pin 44 on the stirrup 45 pivoted at 46 to the fixed frame. The stirrup 45 is connected by the pin 47 with the escapement 48 and bearing 49. A second escapement 50 is pivoted in a bearing 52, connected by rods 53 with the bearing 49. The weight of the escapement mechanism is taken by the spring 55. A slot 56 in the disc 34 co-operates with pawls 48a, 50a, and a slot 57 in the disc 35 with pawls 48b, 50b. To connect the feeder 14 with the bus-bar 16<1>, the breaker 15 is locked " off " and its key withdrawn and inserted into the lock 18. On turning the key in lock 18, the part 31<1> moves clear of the slots 33. in the discs 34, 35, and either selector switch may be closed. If the handle 9 is turned through 180‹ to close the switch 13, the escapement holds fixed the mechanism associated with the handle 8. The key can now be re-turned, 31' entering the slot 33 of the disc 34 and the slot 33<1> of the disc 35. The key is then withdrawn and inserted in the lock of the breaker 15 to release its mechanism, whereby the switch may be closed to interconnect the bus-bar 16' with the feeder 14. To switch over the feeder 14 from bus-bar 16<1> to bus-bar 16 without opening the breaker 15, the bus-bars are brought up to synchronism and the coupler 17 closed. The coupler 17 is then locked " on " and its key withdrawn and inserted into the lock 19. On turning the key, the part 31<1> is moved clear of the slots 33, 33<1>, the pawl 48b engages the slots 57 of disc 35, and the pawl 50a is released from the slot 56 of disc 34. The handle 9 cannot then be moved, but the handle 8 can be moved to close the switch 12. After such movement the handle 9 can be moved to open the switch 13. On re-turning the key in lock 19, the switch 12 is locked " on " and the switch 13 is locked " off." The key is then withdrawn and reinserted in the lock of the coupler 17 permitting it to be moved " off."