GB296745A - Improvements in and relating to electric time switch mechanism - Google Patents

Abstract

296,745. Williamson, C. M., and Williamson, S. June 7, 1927. Winding - apparatus, electric.-Electric time switches which may be used in automatic photographic cameras of the type described in Specification 222,548, [Class 98 (i), Photographic cameras &c.], wherein a cycle of switching operations is effected by a clock which runs down for a certain time and is rewound by electromagnetic action for each cycle, the period of the cycle being adjustable, have the contacts for the winding solenoid and for the controlled devices such as warning lamps and an exposure solenoid arranged in a group mounted adjacent to the clockwork. As shown in Figs. 1 and 2, a spring 17 drives a shaft 11 through a one-way clutch 13 and an escapement mechanism 4 - - 10 the shaft 11 carrying a radial pin 35 bearing against a face cam 34. At the end of a predetermined period, the pin 35 rides on to the raised portion of the cam so forcing a contact controlling lever 30 about its pivot 31 against the action of a spring 33. The consequent movement of the insulated end 32 of the lever 30 first allows the spring blade 19 to bring contacts 23, 24 into engagement, so completing the circuit of the warning lamps 40, Fig. 4, and then permits the spring blade 20 to bring contacts 25, 26 into engagement to complete the circuit of the winding solenoid 36. The energization of the solenoid 36 causes the rotation of a toothed sector 16 to re-wind the spring 17, the escapement being unaffected because of the one-way clutch 13. At the end of the winding movement an arm 37, carried by the sector 16, strikes an insulated pillar 29 carried by the spring blade 19 breaking the winding circuit at contacts 23, 24. The lower end of the pillar 29 also bears on a blade spring 21 closing at contacts 27, 28 the circuit of the exposure solenoid 41. The sector 16 is then driven slowly by the spring 17 to its former position under the control of the escapement mechanism, the pillar 29 being thus allowed to rise and contacts 27, 28 to open. The ends of the blades 19, 20 are however held under the end of the lever 30 until this lever is again tripped by operation of the cam 34. The time of the switching cycle may be varied by adjustment of the cam 34 which may be effected by forming teeth 43 on the cam which are geared to a handcontrolled sector, rotation of which varies the initial position of the cam relative to the pin 35