GB794191A - Improvements in and relating to electric switches - Google Patents

Abstract

794,191. Oil-break switches; snap actuation of switches. ENGLISH ELECTRIC CO., Ltd. Sept. 23, 1955 [Oct. 1, 1954], No. 28336/54. Class 38 (5). A switch has a moving contact element 5 with at least three positions in each of which it is locked by one or more of a number of catches 21a ... 21d biased to engage with locking faces 20a ... 20d moving in correspondence with the element 5 which is connected by a resilient connection to an actuating member, movement of the member causing the stressing of the connection prior to the release of an engaged catch to permit movement of the element 5 under the action of the connection. In the oil-immersed isolator shown, rotation of an operating shaft 8, e.g. in an anticlockwise direction, turns bell crank levers 11a, 11b in a clockwise direction. These levers are freely pivoted on a shaft 12 and move a thrust block 13 to the left to compress springs 18a, 18b, which with springs 18c, 18d are carried on guide rods 14a, 14b and interposed between the block 13 and thrust blocks 15, 16. The blocks 15, 16 are interconnected by links 17a, 17b to which are pivotally connected levers 19a, 19b fixed on the shaft 12. Each lever 19a 19b has two locking faces 20a, 20b and 20c, 20d respectively and in the central " off " position shown, the levers 19a, 19b are locked by catches 21b, 21c engaging faces 20b, 20c The levers 11a, 11b have projections 23a, 23b and the rotation of these levers in the clockwise direction causes the projection 23a to release the catch 21b and free the levers 19a, 19b for rapid clockwise rotation under the bias of the springs 18a, 18b which move the blocks 15, 16 to the left. The moving contact 5 is connected by an insulating link 25 to a crank 24 fixed on the shaft 12. In either of the " on " positions the element 5 is locked against movement by the fixed contact 6 or 7 acting as a stop and by a catch 21a or 21d.