Patent GB-1152700-A (GB)
Title: Electric Time Switch Device.
Inventor: WIEGNER HEINZ
IPC: G04C23/16
Filed: 1967-02-24
Abstract: 1,152,700. Time switches. K. DIEHL. 24 Feb., 1967, No. 8819/67. Heading H1N. A cooker timer of the type wherein automatic on-off operation is determined by setting a finish time and a cooking duration is arranged to function also as a normal time switch (i.e., switched on immediately and switched off after the set time interval). Two embodiments are disclosed in detail but each comprises essentially a switching mechanism, a time drive, and a coupling member which provides a friction clutch (for the latter mode of operation) when urged in one direction and a single toothed dog clutch (for the former mode of operation) when urged in the opposite direction. A synchronous motor 40, Fig. 2 (or 101, fig. 4, not shown), drives clock hands via the usual slipping clutch for setting purposes, and also a time drive to the switching mechanism via a differential 32, 33, 34 (or 136, 191, 137) which is adjustable by means of a knob 2 (or 119) coupled to a finishtime indicator hand 8 (or 124). In the embodiment of Fig. 2, cooking duration is indicated by a line 11 on a cylinder 14 viewed through a narrow slit (12, Fig. 1, not shown) and adjusted by a milled wheel 3 which simultaneously rotates a switching-off member 53 by means of pinion 16 and toothed segment 57. " Automatic " operation.-If knob 3 is set to " automatic " ("A," Fig. 1, not shown), a recess 81 on a cam-plate 62 comes opposite the tongue 80 on a spring-urged lever 76, and a latch 70 holds the cam-plate against return by spring 63. Tongue 80 cannot fall into recess 81 until a tooth 47 on time-driven coupling member 38 enters a recess 51 in member 50 secured to member 53; this occurs at the finish time less the cooking duration. The consequential axial movement of member 38 allows tongue 80 to enter recess 81 and a further tongue 88 closes contacts 89. Member 53, being clutched to member 38, is then time-driven back to its starting position, whereat an extension 58 engages lever arm 59 to remove latch 70 and allow spring 63 to restore cam-plate 62. Tongue 80 is then urged out of notch 81 and contacts 89 open, coupling member 38 being returned by the other end 75 of lever 76 to the position shown. " Time-switch" operation.-If knob 3 is turned to time-switch operation (" T," Fig. 1, not shown), a projection 84 on cam-plate 62 closes contacts 89 while projection 78 engages tongue 80 to cause lever 76 to move member 38 and shaft 48 axially such that a friction plate 49 engages a plate 54 on member 53 which immediately commences time-drive back to its starting position where cam-plate 62 is unlatched and the contacts are opened as for automatic operation. " Manual" operation.-Knob 3 may be set to render the device inoperative (" O," Fig. 1, not shown), or to close the contacts regardless of time settings (" M," Fig. 1, not shown). In the second embodiment, a knob (142, Fig. 4, not shown) is moved axially to change between "T" and "A" operation, and rotated to set a cooking duration which is indicated by the rectilinearly-moving end of a pivoted pointer (164, Fig. 5, not shown). Contacts (129) are actuated similarly to contacts 89 but by a different lever system, the time drive being via a shaft (130) carrying a member (158) to which the coupling member (155) may be clutched by a tooth (162) at the computed start time, or by friction plates (156) for immediate time-drive. Shaft (130) is at right angles to the axes of the control knobs and can thus be extended to operate a plurality of switching mechanisms from the one motor (101).