GB620813A - Improved setting means for timing devices controlling electric switches - Google Patents

Abstract

620,813. Time switches. LONDEX, Ltd., and DOCKER, C. E. Jan. 27, 1947, No. 2473. [Class 38(v)] A timing device manually reset in the opposite direction to that in which it is driven by an electric motor or clockwork 29, comprises a shaft 1 rotated clockwise through a friction coupling 2 and freely carrying a disc 4 having a slot 8 which receives the bent end of a pivoted contactcarrying lever 12. A disc 5 fast on the shaft has a notch comprising a radial shoulder 6 and a resetting surface 7, and a pin 10, Fig. 2, on this disc engages a larger hole or notch 11 in the disc 4 to provide lostmotion corresponding to the angular extent of the surface 7. A pointer 19 free on the shaft 1 is permitted the same lost-motion between pins 20, 21 on a setting disc 22 fixed to the shaft. A rotatable setting plate 24 co-operating with a scale 27 carries a stop 25 and is held set by a clamp 26. The device is reset by reversely rotating the disc 22 until the pointer 19 engages the stop 25, this movement first lifting the lever 12 from the slot 8 by the surface 7 and bringing the pin 21 into driving engagement with the pointer. The contact 15 will now be held open (or closed) during a timing operation whilst the shaft 1 is driven clockwise to first engage the pin 20 and pointer 19 and line-up the shoulder 6 with the slot 8, and then to rotate both discs 4, 5 until the pointer 19 engages a fixed zero stop 23 and the slot 8 receives the lever and the contact 15 closes the circuit.