GB614949A - Improvements in or relating to clock-controlled electric switch gear - Google Patents

Abstract

614,949. Time-switches. SMITH & SONS (ENGLAND), Ltd., S., and ELLIS, J. W. June 6, 1946, No. 17254. [Class 38 (v)] A time-switch suitable for controlling a radio set, comprises a cam-member 18 attached to a spindle 17 which is rotatable by a 24-hour pinion 20 and is axially movable in a bush 11 carried by a plate 10 fixed to the switch frame, the cam-member 18 co-operating with setting- discs 12, 24 by means which impart rapid opening and closing movements to contactarms 34, 35. The disc 12 is fixed to the bush 11 and the whole is adjustably held against the plate 10 by a friction-washer 13 and spring- washer 15, being adjustable to vary the switching-on time, by a pinion 8 on an operating spindle 7. The cam 18 has a rim 22, notched at 19, which co-operates with a lug 23 pressed out of the disc 12, the notch 19 being so shaped that the lug 23 moves rapidly into, but slowly out of, it. The disc 24 is fixed to a bush 30, and is connected to the disc 12 so as to be rotatable therewith, but axially - movable thereto, by a lug 26 on the disc 12 which engages a slot 27 in the rim 25 of the disc 24. The disc 24 and cam 18 are urged towards the disc 12 by a forked blade spring 31, and a lug 28 pressed out of the disc 24 bears on the cam 18, being so shaped as to snap into and move slowly out of a slot 29 in the cam-face. The contact-arms 34, 35 are normally held apart by a fixed stop 42 and the spindle 17, but when, after a predetermined rotation of the cam 18, the notch 19 coincides with the lug 23, the disc 24 and cam 18 are suddenly moved axially by the spring 31 and the contact-arm 35 is snapped-over by a tension-spring 39 to engage the arm 34, which remains stationary due to a slot 36 in the bush 30 which it engages. Further rotation of the cam 18 brings the slot 29 opposite the lug 28, so as to impart further axial movement to the disc 24 and snap the arm 34 away from the arm 35. The switch parts are restored to their initial positions by continued rotation of the cam. A 24-hour indicating scale 16 is frictionally mounted on the bush 11, so that the switch may be set to close at a predetermined time, and a.m. and p.m. indications are provided by a disc 54 driven by a 24-hour wheel 53. In Figs. 6-8 (not shown), the setting-disc 24 is also adjustable and is geared to an indicating-disc showing the time the contacts are required to open. In a modification, separate switches may be controlled by the axial movements of the cam 18 and setting-disc 24.