GB445138A - Improvements in or relating to time control devices for electric switches - Google Patents

Abstract

445,138. Time switches. GIORDANI, A., and GIORDANI, A., 2, Corso Garibaldi, Padua, Italy. Feb. 27, 1935, No. 6249. Convention date, Feb. 27, 1934. [Class 38 (v)] Insertion of a finger in a selected hole of a selector disc 1 and rotation of the latter till the finger abuts against a stop 4 after the manner of an automatic telephone winds up a spring 10 ; when the finger is withdrawn the disc rotates backwards and operates a switch, which remains in the " operated " position for a time determined by the hole selected. The stop 4 is yieldingly mounted so that it may be pressed to the dotted position by the finger to impart an additional movement to the disc 1 corresponding to half a time unit. The device is specially applicable in photography. The disc 1 is fixed to an axle 6 which is controlled by the spiral spring 10 and the axle 6 has also fixed to it a plate 11. Pivoted at 14 on the plate 11 is a lever 13 carrying at one end a pawl 15 and at the other a spring urged contact 2 which is adapted to engage contacts on a contact carrier 12 on the plate 11. A spring 16 tends to hold the lever 13 in the position shown in Fig. 4. When the finger rotates the disc 1, the disc 11 moves counter-clockwise, Fig. 4, and the pawl 15 slides over the teeth of a ratchet wheel 19. When the finger is withdrawn, the spring 10 rotates the discs 1, 11 backwards and the pawl 15 engages the wheel 19 which is connected wtih a train of gearing. The resistance to movement of the wheel 19 causes the lever 13 to be moved about its pivot 14 and the contact 2 to be moved into its alternative position against the action of the spring 16. The pawl 15 then drives the wheel 16 and its train of gearing till after the predetermined time the pawl is lifted from engagement with the wheel by a stop 21. The spring 16 then restores the lever 13 and contact 2 to their original position.