GB782659A - Improvements in electric time switches - Google Patents

Abstract

782,659. Time switches. HORSTMANN GEAR CO., Ltd. Dec. 28, 1955 [Dec. 24, 1954], No. 37371/54. Class 38 (5). A switch similar to that of Specification 774,186 has a knob 35 attached to a spindle 17 carrying a contact-operating cam 23. The knob is normally urged to the right by a spring 24 so that a projection 41 on a concentric ring 36 engages a recess 42 in the rear of the knob, so that rotation of the latter causes rotation of the ring 36 to set the duration of the operation relative to a scale 43 and the cam 23 closes contacts 13 to start the timing motor. To delay the start of the operation, the knob is pulled to the left and further rotated to the desired extent, the projection 41 riding over the rear face of the knob and the ring 36 being held against rotation by a friction pad 51. A motor restores the spindle over gears 14, 15, 16 and a friction clutch 18 until spring 24 moves the knob to the right when projection 41 and recess 42 re-engage, this movement causing cam 23 to close contacts 26. The spindle continues to rotate until a cam recess 27 comes opposite a projection 50 on contact arm 30, so that switches 13, 26 open. If the knob is turned so that its pointer 44 comes opposite numeral 4 on scale 43, switch 26 is closed, but a projection 29 on the cam holds motor switch 13 open, so that the timing mechanism becomes inoperative. Specifications 782,660 and 782,661 also are referred to.