Patent GB-924000-A (GB)
Title: Improvements in or relating to time and hand controlled actuating mechanism
Inventor: BOWEN TOM
IPC: G04F3/06
Filed: 1958-08-12
Abstract: 924,000. Time-switches. S. SMITH & SONS (ENGLAND) Ltd. Aug. 4, 1959 [Aug. 12, 1958], No. 25947/58. Class 38 (5). A switch comprises two relatively settable members which may be moved together in one direction from a datum position by a common setting member to a position determining the switching-off time, movement of the setting member in the reverse direction leaving one of the settable members behind and moving the other to a position determining the switching-on time, the settable members then being movable under the control of a constant-speed motor to actuate the switch at the predetermined times, movement of the setting member from the datum position in the reverse direction directly controlling the switching-on and off independently of the constant-speed motor. In the embodiment shown, clockwise rotation of spindle 16 rotates a member 18 and a downturned lug 30 thereof engages the left-hand end of a slot 23 in a cam 15, constituting one of the settable members, which is thereby also rotated. The cam 15 has a radial slot 22 engaged by a down-turned lug 27 of a latchpiece 17 which also has an upturned lug 26 which engages the end 7 of a groove 20 in a second cam 14, constituting the second settable member. Thus both cams are rotated clockwise, against the action of springs 65, 64. The cams are formed with interrupted peripheral gear teeth which come into engage. ment with pinions 44, 45 geared to the constantspeed motor 62, which may be a synchronous motor, the pinions being so mounted that they jump out of engagement with the gear teeth during this direction of rotation. During this rotation, the lug 27 on piece 17 rides along a cam surface 31 on a fixed plate 19 and is moved radially inwards in slot 22, thereby bringing lug 27 opposite a finger 29 on member 18. When the finish time, as shown by a radial slit 56 in an indicating disc 51, is set, the spindle 16 is turned in the reverse direction and lug 26 moves away from the end 7 of groove 20 leaving cam 14 in the set position. Rotation of spindle 16 continues until the on time, as shown by the radial edge of a tab 53 on an indicating disc 50, is set. If an attempt is made to set an on period of more than, say 6 hours, the lug 26 engages a step 8 in groove 20 and rotates cam 14 back. The cams are then returned to their datum positions by springs 64, 65 under the control of the motor 62. During this movement, the lug 27 rides on the cam surface 31 and is moved outwards by a spring 35 so that lug 27 is clear of finger 29, and lug 26 is moved clear of the step 8. When the " on " time is reached, the interrupted part of the gears on cam 15 reaches pinion 44, and the cam is moved rapidly by spring 65 until the lug 27 engages a stop 34 on plate 19. Similarly, at " off " time, cam 14 is disengaged from pinion 45 and is moved rapidly by spring 64 until end 7 of groove 20 abuts lug 26. The cams control contacts 9, 10, 11 via tappets 12, 13. To control the switch manually, spindle 16 is rotated counter-clockwise from the datum position and lug 30 on member 18 engages a lug 33 on piece 17 and forces the latter radially inwards to a position where lug 27 is clear of stop 34, the cams then being rotated counterclockwise by springs 64, 65 until lug 27 engages a further stop 46. In this position the switch is closed, but the motor is " off."