GB696142A - Improvements in or relating to torsion spring arrangements in electric circuit breakers - Google Patents

Abstract

696,142. Actuation of switches. GENERAL ELECTRIC CO., Ltd., and TAYLOR, S. Nov. 9, 1951 [Nov. 9, 1950], No. 27421/50. Class 38 (v) [Also in Group XXXII] In a circuit breaker a composite torsion spring comprising an outer tubular member and an inner rod is used to assist in opening the circuitbreaker contacts. The Figures show an arrangement in which two composite springs are used, each spring comprising an outer torsion tube 11 splined at one end into an adjustablyfixed supporting member 10 and an inner torsion rod 18 splined at one end into the other end of the tube 11 and at its other end into a lever assembly 2. The lever assembly 2 has bosses 16 rotatably supported in the members 10, the bosses 16 providing bearings for main contact lifting levers 3 interconnected by a pin 23 to which a pull rod 24 is connected. The lever assembly 2 has arms 25 which can contact the pin 23 and a U-shaped part 27 having an adjusting bolt 29 which abuts a stop member 28 to limit the movement of the lever 2. To close the circuit-breaker, the rod 24 is raised and during the last part of its travel, the pin 23 engages the arms 25 and moves them into the chain-line position of Fig. 2 to stress the torsion springs 11, 18. When the circuitbreaker is opened, the arms 25 move down with pin 23 and levers 3 until the bolt 29 engages the stop 28, the force derived from the springs assisting in accelerating the moving contact or contacts (not shown). Each member 10 is rotatably retained in an aperture in a frame by a clamping member 13 to which it is bolted and has a depending lug 12 engaged by bolts 30, which may be adjusted to rotate the member 10 to vary the loading of the associated torsion spring. The Provisional Specification describes an arrangement having one composite torsion spring.