GB411708A - Improvements in electric time switches - Google Patents

Abstract

411,708. Time switches. LANDIS & GYR AKT.-GES., 1, Hofstrasse, Zug, Switzerland. Aug. 3, 1933, No. 21825. Convention date, Aug. 23, 1932. [Class 38 (v).] A time switch comprises a twenty-four hour dial b driven by clockwork or a synchronous motor provided with tappets d which are adapted to operate two switches detachably mounted in close proximity to the dial. One switch comprises two contact springs e moved into and out of contact by means of a cam i driven by a tappet d and pinion d<1>. The switch is mounted on a bar g having a plate k detachably mounted on the base a. The other switch s comprises two contact springs one of which has an insulating extension o to which is pivoted a spring controlled arm n carrying a pawl m which rests against one limb of a V-shaped spring l between the limbs of which is positioned a triangular cam x rigidly connected to a pinion d'. In the position shown, if the cam p is turned anticlockwise by hand a nose q engages the pawl m which is prevented from moving by the spring l and so slides to the left along the spring moving the member o to close the switch s. The switch is held closed by the notch r engaging a spring catch, not shown. When the tappet d rotates the pinion d<1> and hence the cam x, the spring l moves upwards out of the way of the nose r and the switch is opened. While the cam x is in this position it is impossible to close the switch s. Thus with the tappets d arranged diametrically opposite as shown, while the right hand switch is closed it is impossible to close the switch s or if the switch s has been closed it is opened when the right hand switch is closed. A pair of arrows carried by the extension of the part o are visible in turn through a window to indicate the position of the switch.