GB679596A - Electrical timer - Google Patents

Abstract

679,596. Time switches. GENERAL CONTROL CO. Jan. 29, 1951. No. 2201/51. Class 38 (v). A time switch adapted to operate contacts S1-S5 at the end of a time period is set in operation by closing a switch Ss whereupon a solenoid 86 is connected in circuit between lines t1, t2 ; the solenoid operates a lever 43 pivoted at 82 thereby operating (a) a clutch 35 which connects a shaft 19 driven by a continuously running motor 18 to a timing disc 47 and (b) a switch s2 which completes a maintaining circuit for the solenoid 86 ; the timing disc 47 rotates, winding up a spring 81, and at the end of the time period a projection 49 on it engages a lever carried by an adjustable disc 52, the lever in turn operating a switch s1 also carried by the disc 52 so that the maintaining circuit for the solenoid 86 is broken and a relay 126, controlling the contacts S1 ... S5, operated. In the arrangement shown in Fig. 8, the relay 126 is energized to start with and is de-energgized by the operation of switch s2 at the beginning of the time period. At the end of the time period when switch s1 operates and solenoid 86 is de-energized, the lever 43 moves to declutch the disc 47, which then returns to its starting position under the influence of the spring 81, and to release the switch s2 which now completes the circuit to the relay 126 since the switch s1 has also been released by the return of the disc 47. In a modification, Fig. 9 (not shown), the relay 126 instead of being de-energized and energized respectively at the beginning and end of the time period is normally de-energized and only energized at the end of the time period. The lever 43, in addition to its other functions, carries a roller 103 which acts as a brake to the return movement of the disc 47 and, by entering a slot 106, determines accurately its zero position. Should the supply current fail, the lever 43 is locked in its clutching position by a lever 174 so that when power is restored the time cycle continues. The relay 126 comprises a solenoid which operates a plunger, Fig. 2 (not shown), which operates a lever about a shaft 131 and causes a bar 137 to operate the contact springs 144 of the five switches S1 to S5. An additional switch s3, operable by a push 158 serves to reset the device, if desired, during the timing cycle. A switch Si also enables the switches S1 to S5 to be operated without timing. The adjustment of the disc 52 to determine the length of the time period is effected by rotation of a knob having on its shaft a rubber grommet engaging the edge of the disc 52.