Patent GB-675768-A (GB)
Title: Improvements in and relating to control devices for electric washing machines
IPC: D06F34/08
Filed: 1949-06-14
Abstract: 675,768. Time switches. BRITISH THOMSON-HOUSTON CO., Ltd. June 14, 1949. [June 19, 1948] No. 15807/49. Class 38 (v). [Also in Group XXIV] A control device for a washing machine comprises a sequential control for a series of operations, an interval control for varying the duration of one of the operations, a motor for alternatively driving the controls, a train of gears for transmitting motion to the controls, and a stop for maintaining one gear stationary so as normally to cause the motor to drive the sequential control over others of the gears, the interval control having a setting knob connected to the stationary gear through a friction clutch. The sequential control comprises a cam drum 15 co-operating with a switch assembly 6, which may be similar to that of Specification 636,039, and is driven by a motor 19 through gears 20, 22, 23, 24 and 25. The gear 25 is secured to a shaft 14 to the upper end of which is fixed a gear 26 which co-operates with a spring-pressed pawl 28 .pivoted to the drum 15 to rotate the latter clockwise, a second setting knob 2 being rotated through a pin- and-slot connection 33, 34. The knob 2 is provided with indications showing the operation in progress and may be rotated clockwise by hand to adjust the drum 15, the pawl 28 riding over the gear 26 to permit this. Reverse rotation of the knob and drum, so that an operation may be repeated, is made possible by engagement of the side of a recess 36 in the knob with a part 35 of the pawl which is swung clockwise to disengage it from gear 26. The gear 24 is mounted on a pin 39 on a gear 37 which is normally prevented from rotation, so that gear 25 is driven, by a stop 40 on a member 42 connected by a spring 43 to a member 41, pivoted at 44, and biased clockwise by a torsion' spring 45. At the commencement of the "wash" period, a cam 46 on the cam drum engages a lug 47 on member 41 which is swung counterclockwise together with member 42 so that the gear is freed. Rotation of gear 23 now causes gear 24 to roll around the former, thereby rotating gear 37 and a knob 3 connected thereto by a spring, friction, clutch 38. The knob 3 is adjustable by hand to vary the "wash" period and carries a lug 48 which is adjustably spaced from the end 49 of the member 42. At the end of the predetermined interval, the lug 48 engages the end 49 and the stop 40 re-engages the gear 37, so that the drive is transferred to the drum 15 again and the cam 46 releases the member 41, which is returned to its normal position by springs 43, 45. Water to the machine is supplied through solenoid operated valves, not shown, giving "hot" and "warm" water respectively, "medium" water being supplied when both valves are open. The solenoids are controlled by a switch 50 having spring blades 57, 58, 59 carrying contacts 61, 62, 63 respectively, contacts 61, 62 normally being closed, so that "warm" water is normally supplied, and contacts 62, 63 normally being open, as shown. The switch may be set in any one of three positions by a lever 5 having a part engaging a member 671 pivoted at 68 and having cams 69, 70. Normally these cams are out of engagement with the blades 57 ... 59, but on clockwise movement of the lever 5 through one step to the Fig. 7 position, contact 63 is moved so that it nearly engages contact 62, the contact finally being made by upward movement of the contact 62 by the end 76 of a bellcrank lever 73, the other end of which is engaged by a cam 75 on drum 15 at the beginning of the "wash" period. Since the contact 61 follows and remains in engagement with contact 62, both valves are opened and "medium" water is supplied. Further movement of lever 5 to the Fig. 8 position has little or no extra effect on contact 63, but cam 69 is moved so that when contact 62 is pushed up by cam 75, the contact 61 cannot follow, the contacts thereby being opened and "hot" water being supplied.