GB625001A - Improvements in or relating to time delay switches - Google Patents

Abstract

625,001. Time switches. LUCAS, Ltd., J., and ALLEN, A. M. July 24, 1947, No. 19862. [Class 38(v)] A switch for controlling a direction indicator on a vehicle is closed by rotating a spindle which simultaneously winds a clockwork mechanism. When the spindle is released the clockwork unwinds but the switch remains closed for an interval of time due to a lost-motion device between the clockwork and switch actuator. Fig. 5, is a plan of a part of the switch in which 2 and 3 are the moving and fixed contacts and 7 the winding spindle of the clockwork The upper end of the spindle carries an insulating cylindrical member 8 formed with a sector-shaped slot 9 in which a lever 10 is pivoted at 11. If two indicators are to be operated a second slot 9 and pivoted lever 10 are provided to actuate a second moving contact 4 into and out of engagement with a second fixed contact (not shown). Each lever 10 can oscillate about its pivot 11 through an arc bounded by the walls of the slot 9. In the position shown in Fig. 5 the spindle 7 has been rotated counterclockwise to wind the clockwork and cause the lever 10 to press the contact arm 2 into engagement with the contact 3, the lever riding up and engaging behind a cam-shaped projection 12 formed on the arm 2. As the clockwork unwinds, the member 8 rotates clockwise while the lever 10 remains stationary against the projection 12 until it is engaged by the wall of the slot 9. The lever then rotates with the member 8 and rides over the projection 12 causing the arms 2, 3 to separate. The switch arm 4 is similarly closed against its fixed contact and opened automatically after an interval of time by rotating the spindle 7 in a clockwise direction. Fig. 7 shows a modification in which a second lever 13 in the form of a ramp is pivoted on the pin 11 and engages the moving contact before the lever 10 so that a more gradual movement of the contact is produced. The clockwork is wound up by a rotation of the spindle 7 in either direction by the arrangement shown in Fig. 2. The spindle carries a symmetrically-shaped cam 14 which co-operates with a pin 15 projecting from a plate 16 pivoted at 16a. The plate carries a rack engaging a pinion 18 of the clockwork train the speed of which as it runs down is controlled by an escapement. The main spring 17 is connected to the plate 16 and to the casing of the apparatus. Rotation of the cam 14 in either direction moves the pin 15 and plate 16 to strain the spring 17.