Patent GB-817920-A (GB)
Title: Improvements in or relating to clock-operable electric switches
IPC: G04C23/16
Filed: 1957-03-25
Abstract: 817,920. Switches held set and freed mechanically; time switches. INTERNATIONAL REGISTER CO. March 25, 1957 [April 9, 1956], [No. 9731/57. Class 38 (5). A switching device for closing contacts at a pre-set time and in which the contacts may also be manually operated " on and " off," the device being set for automatic operation by movement of the " on " " off " knob from its central " on " position to a third " auto position, comprises a synchronous motor 41 having an output shaft 43 which drives through gears 44, 46 a shaft 47 carrying a second hand 16. The minute hand 15 carried by a sleeve 55 is driven from shaft 43 by gears 48, 49, 53, 54, there being a slipping coupling between gears 53, 54. The hour hand 14 and its sleeve 63 are driven from sleeve 55 by gears 54, 58, 61, 62, the gear 62 and sleeve 63 being axially shiftable and urged to the left, Fig. 6, by a spring 64. The pointer 17 is set to the time at which the contacts are to close by a shaft 75, the shaft being pushed in to engage pinion teeth 78 with a gear 81, rotation of shaft 75 then causing rotation of a gear 66 meshing with gear 81. The gears 66, 81 are held in adjusted position by a spring 83 which presses gear 81 against the plate 31. The hands 14, 15 may be adjusted by pulling the shaft 75 to engage pinion teeth 77 with gear 58, which can then be rotated. The opposed faces of gears 62, 66 have double-shaped cam-projections 86 ... 89 which co-operate to move the gear 62 away from gear 66 to close the contacts 111. The latter are carried by spring arms 108 biased together and mounted in a casing 92. A cam 122 between the arms 108 is fast with a sector cam 135 meshing with a pinion 142 on a spindle 21. The latter is biased to its central " on " position by the spring arms 108, but can be held in either the " off " or " auto " position by a latch 151 which engages one or other of recesses 144<SP>1</SP>, 1451 on the face of the cam 135. In the " auto " position, the latch is pressed to the left, Fig. 6, by a spring 161 into the recess 145<SP>1</SP> which is deeper than the other, so that a part 154 of the latch is placed in the path of rightward movement of the gear 62 at the predetermined time. When the latch is disengaged from recess 145<SP>1</SP>, the contacts are allowed to close. In the " off " position, the latch engages recess 144<SP>1</SP>, and can be disengaged by manual rotation of shaft 21 to the " on " position. The housing 92 has positioning bosses 94, 95, 95<SP>1</SP> received in apertures in a rear mounting plate 32, and its cover 93 has bosses 101 with recesses 102 engaged by spring fingers 104 pressed out of the plate 31. In a modification, Figs. 22, 23, the cam 135 is replaced by separate latching and unlatching cams 165, 166, having a lostmotion connection 174, 175. The latch 168 in this arrangement is pivoted at 185 and biased into engagement with the edge of cam 165 by a spring 189, said edge having the latching recesses formed therein and is released from the " auto " recess 2451 by the gear 62<SP>1</SP> as in the first arrangement. The latch may also be deflected out of either recess by a surface 195 or 196 on the cam 166 on manual rotation thereof, the lost motion 174, 175 allowing the disengagement of the latch before the cam 165 starts to move. The latter cam in addition to being biased by the contact arms, is acted on by a spring 192.