GB848415A - Time delayed electric switching device - Google Patents

Abstract

848,415. Time switches. WESTERSTRAND-SONER A. B. Dec. 21, 1956 [May 25, 1956], No. 39130/56. Class 38 (5). A time switch, Fig. 1, comprises a control shaft 11 biased into an initial position by a weak spring 15, the movement into this position after the shaft has been displaced by a knob 12 being retarded by a magnetic brake 18 drawn by a gear wheel 17 connected to the shaft through friction plates 16. A two-armed lever 10, 13 in the shaft carries a pin 9 received in a circumferential slot 8 in a disc 4 connected to the movable bridging contact 1, the disc 4 being biased by a strong spring 3 acting in the same direction as the spring 15. To set the switch so that the contact 1 bridges fixed contacts 2, the shaft is rotated against the bias of the springs, the pin 9 engaging an end of the slot 8 to drive the disc. 4 On release of the knob 12 the contact 1 is retained closed by a resilient detent 6 engaging a recess 5 in the disc 4, while the shaft 11 is slowly restored. When the shaft reaches its initial position-which movement is permitted by the angular extent of the slot 8, a projection 14 on the lever releases the detent 6 and the contact 1 is moved by the spring 3 to its initial open position. In another construction, Figs. 2, 3, the spring 3 acts on a rotatable sleeve 20 connected to the disc 4 by a pin 22 on a sleeve arm 21, the arm working within an arcuate recess 23 in a wall 24, the angular extent of the recess corresponding to the angle through which the shaft 11 must be turned to set the switch. The lever 10, 13 is pivotally connected to a pawl 25 having a pin 27 guided in a groove 26 and a finger 28 cooperating with a notch 29 in the disc 4. To set the switch from the initial position shown in Fig. 3 the shaft 11 is turned counterclockwise against the bias of the springs 3, 15, the pin 27 moving in the groove portion 26a and the finger 28 driving the disc 4 until the spring- biased detent 6 is received in the recess 5. On release of the knob 12 the shaft 11 slowly restores, the finger 28 being held clear of the side 31 of the notch 29 by the groove 26a, and eventually the projection, 14 releases the detent 6 permitting return of the disc by the spring 3. Additionally, the shaft 11 may be turned clockwise from the initial position into a number of other switching positions in which the switch is retained by further detent means (not shown), the pin 27 moving into the groove portion 26b whereby the finger 28 enters the notch 29 to drive the disc 4. In there other switching positions the spring 3 is ineffective since the pin 22 is freed from the disc and the switch must be restored into its initial position by hand. In a further modification (Figs. 4, 5, not shown) the lever 10, 13 carries a leaf spring which is deflected by a fixed cam surface upon rotation of the shaft 11 to effect a driving connection with the disc 4. In a shallow form of construction (Fig. 6, not shown) the switch contacts are situated circumferentially around the outer periphery of the disc 4.