GB826486A - Improvements in or relating to time controlled switch or valve mechanisms - Google Patents

Abstract

826,486. Time switches. MIDGLEY, A. H. Aug. 28, 1957 [July 9, 1956], No. 21212/56. Class 38 (5). [Also in Group XXIX] In an electric cooker, time-controlled mechanism automatically effects the closing and opening of a switch at predetermined times to bring about delayed starting and stopping of a cooking operation. In the first example two spring arms 22, 23, Fig. 2, are controlled by cams 20, 21 to actuate two switches 28, 30 and 29, 31 after predetermined time delays. The switch 29, 31 controls an electric motor which is geared to the cams 20, 21 mounted respectively on a shaft 2 and a sleeve 14, Fig. 1, and the switch 28, 30 controls the heating circuit. The gearing from the motor to the shaft 2 includes a ratchet clutch to allow setting of the shaft 2 by a knob 18. The sleeve 14 carries a disc 15 connected by pins 16 to the knob 18, the pins 16 passing through arcuate slots in a dial plate 1. Clockwise rotation of the knob 18, Fig. 3, sets the delay scale of the dial relative to a fixed index 19, Fig. 1. The knob 18 is then moved counterclockwise to position the index mark O, Fig. 3, with respect to the cooking scale on the dial 1. Upon such setting the switch 29, 31 is closed and the motor drives the cams 20, 21, Fig. 2, clockwise. At the end of the delay period the cam 20 allows the heating circuit switch 28, 30 to close, Fig. 6A. At the end of the cooking period the cam 21 allows both switches 28, 30 and 29, 31 to open. The knob 18 may be located in the position shown in Fig. 3, in which the motor switch 29, 31 is open and the heating circuit switch 28, 30 is closed so that a further switch (not shown) controls the heating circuit.