Patent GB-1054413-A (GB)
IPC: H01H43/12
Abstract: 1,054,413. Time switches. CONTROLS CO. OF AMERICA. Jan. 15, 1964 [Feb. 6, 1963], No. 1740/64. Heading H2B. A programme controller (for washing machines, for example) comprising switches operated by cams 12 which are stepped automatically by the timing motor 35 after variable time intervals or stepped continuously for rapid advance to a desired starting position or to by-pass part of a programme is provided with a further switch 1 which disconnects the controlled circuits automatically whenever the cams are driven through more than one step in rapid sequence. A shaded pole motor 35 is normally energized via a series resistor (Fig. 8, not shown) to drive a timing gear train 52 and when the resistor is short-circuited the armature 34 is pulled to the left into frame 36 against the force of a spring 38 acting via a lever 44 and with a balance weight 42 to prevent movement of the armature 34 due to vibration of the equipment on which the device is mounted. Clutch 28, 30 is thus engaged to provide an additional drive to the gear train 20 . . . 27 which drives a bank of cams 12 operating respective control switches (not shown). The cams 12 are adapted to be moved in " steps " of about six degrees which correspond to one revolution of gears 23, 24 and their shaft 110, which is journalled in a fixed bush 64. Shaft 110 also carries wipers 112 co-operating with part of a printed-circuit board 94, other interconnected parts of which are engaged by wipers 114 (which rotate with cams 12) and by wipers 90 mounted on an assembly 74 supported on the bush 64. A spring 82 urges assembly 74 to the right such that teeth on a cylindrical portion 72 are normally in clutching engagement with teeth on a gear 63 which is rotatable on bush 64 and driven by the timing gear train 52. Thus one revolution of wipers 90 may take for example, six minutes, and during this rotation a clock spring 104 is tensioned. Wipers 114 determine the position (and hence the time interval) at which wipers 90 short-circuit the resistor in series with motor 35 thereby engaging clutch 28, 30 and causing cams 12 to be driven. During this action a face cam 108 driven with gears 23, 24 moves a rod 106 to the left, pushing the assembly 74 against spring 82 to uncouple the teeth on parts 72 and 63, whereupon spring 104 returns th assembly 74 (and hence wipers 90) to zero position. Wipers 112 maintain the short-circuit on the series resistor until shaft 110 has completed a revolution and the cams 12 have thus completed one step. The clutch 28, 30 then being disengaged, wipers 90 commence another timing action determined by the new position of wipers 114. Rapid advance of cams 12 over more than one step is provided for by one of the wipers 114 which fully energizes the motor 35 (by-passing the series resistor) until it reaches part of the printed-circuit which is not energized, this being determined by pushbuttons set for the desired programme (Fig. 8, not shown). Time switches 1 and 2, connected inter alia to de-energize the controlled circuits when the cams 12 are driven for more than one step in rapid sequence, are operable by a lever 158 pivoted on a bracket 160 for movement perpendicular to the plane of the drawing but also capable of rocking sideways. A blade spring 164 urges lever 158 to rock such that its lower end tends to move to the right into the path of a cam 180 which, when revolved with gears 23, 24 during a stepping action, pivots lever 158 to operate switches 1 and 2 (Figs. 3 and 4, not shown). During a timing function of assembly 74, however, the lever 158 is restored by the bent end 166 of a lever 168 pivoted at 170 with its other end bearing on the periphery of assembly 74 (as shown). When assembly 74 is returned to zero position the lever 168 drops into a notch in its periphery (Fig. 5, not shown) thus allowing lever 158 to be rocked. However, when the cams 12 are being stepped following a timed interval a small rotation of gears 23, 24 is necessary before the assembly 74 is uncoupled to return to zero and this rotation brings a part of cam 180 behind lever 158, preventing it from being rocked into the operative position until gears 23, 24 have completed one revolution. If a further stepping function follows immediately the lever 158 and switches 1 and 2 will then be operated, but if a timed interval commences the lever 168 returns lever 158 to its non-operative position shown. In a modification (Figs. 9 to 11, not shown) the motor armature does not slide upon full energization but a sliding clutch is operated directly by the extra magnetization; this action is also utilized to provide delayed rocking of a lever operating a snap-action switch to de-energize controlled circuits during rapid advance of more than one step. (See also Specification 1,054,414).