GB190703A - Improvements in automatic cut-out devices for electrical circuits - Google Patents

Abstract

190,703. Soc. L. Drault et C. Raulot- Lapointe. Dec. 22, 1921, [Convention date]. Switches, quick-break; time-limit devices.-A readily-adjustable short-time switch comprises a knife blade 1 and an actuating lever 2 on the same pivot and connected together by a spring and forked operating member 6 carrying an external spring-mounted handle 5 and an internal loosely-mounted catch 23. To close the switch, the handle is first withdrawn from locking engagement with the slotted cover and then swung over to the vertical position. In this movement a pin on the operating lever 6 drives links 10, 12 to move a piston 14 freely along its cylinder 15, which is integral with the cover, against the action of springs 24, 25. At the end of the movement a lever 17, 18 freed from the link 10 drops through a hole 16 and takes up a position behind the end of the piston-rod to prevent the return of the piston. At the same time, the loose catch 23 engages the actuating member 2 so that, when the operating handle is returned, the lever 2 is carried with it, driving the blade into the closed position, where it is retained by the looking engagement of the handle with the cover. The return movement lifts the locking lever 17, 18 and the cylinder returns slowly under the action of the spring 24, 25 at a rate depending on the effective area of a variable port 27 which is covered by a rotatable throttle plate 28 having a circular groove the cross-section of which gradually increases, the larger end being open to the atmosphere. The final movement is rapid owing to the exposure of orifices 30, and the piston rod strikes a rod 19 which, through links 20, 21, 22, lifts the cable member 23 and frees the switch mechanism to produce a quick break under the action of a spring.