GB498376A - Improvements in, and connected with, overload-released contact mechanism for automatic electric switches - Google Patents

Abstract

498,376. Electrically released switches ; actuation of switches. CRABTREE & CO., Ltd., J. A. (Schiele Industriewerke) July 20, 1937, Nos. 18532/38 (divided out of 498,325), and 31212/37. [Class 38 (v)] Overload-released contact mechanism for an automatic switch comprises a pair of oppositelyacting springs, one tending to close, the other to open, the contacts, the moving contact being movable together with a trigger by the opening spring while a catch co-operating with the trigger is carried by a part under the influence of the closing spring. Manual means operative on the catch-carrying part is adapted to re-engage the catch and trigger to allow the contacts to close, and an automatic trip is adapted to free the trigger for disengaging the contacts while remaining in the path of the catch or trigger to prevent reclosing of the contacts after operation of the manual means as long as the trip is in the tripping position. The contacts may operate to open the tractive magnet circuit of the automatic switch. In Fig. 1, a single spring 1 is provided with a lower closing part acting in the direction of the arrow P, and with an upper opening part acting in the direction of arrow P<1> and carrying the movable contact 1a. The spring 1 is secured to a fixed support 3 and carries at a point 5 a catch plate 4 which co-operates with a trigger 4a on the upper part to hold the contact la in engagement with contact 6. A trip lever 9 on a pivot 7 is adapted to break the engagement between 4, 4a to permit the upper part of 1 to open the contacts by moving against the back stop 10. Pressure applied to a button 11 re-engages the latch 4, 4a and when the pressure is released the lower part of 1 recloses the contacts provided 9 is inoperative. Two springs interconnected at the point 5 may replace the single spring 1, and the spring or springs may be laminated. A trip-button may act on the trigger 4a. In Fig. 3, the trigger 4a engages a slot in the upper end of a plate 4<1> which is slidable on rivets 5, 8 on plate 4 to release the connection when the trip lever 9 rises. In Figs. 5, 6, the movable contact 12 isr caried on a catch plate 20 on a rod 18 which is slidable in a fixed bracket 19 and urged in the opening direction (shown by the arrow) by a spring 14 bearing at one end against a carrier 16. Rod 18 S slides freely through the carrier, which carries a rod 17 slidable in bracket 19 and plate 20, and carries the closing spring 11a. When the trip lever 9 is rotated, it lifts the end of trigger 15 clear of plate 20 and, since 15 is attached to the carrier 16, the parts assume the Fig. 6 position. When the button 22 is pressed into engagement with pin 20a on carrier 16, the parts 15, 20 re-engage, and when the button 22 is released, the spring 11a moves the carrier to closed position. The switches shown may open, when tripped, the circuit of the holding coil of a circuit-breaker. One Provisional Specification refers to electromagnetic releases, and the other to Specification 498,325.