GB1190568A - Improvements relating to Washing Machines. - Google Patents

Abstract

1,190,568. Washing machines. HOOVER Ltd. 11 July, 1967 '[27 July, 1966], No. 33788/ 66. Heading D1A. A washing machine has a timer controlling a sequence of operations including two timed pumping periods during the first of which a level responsive device is actuated at a predetermined level which actuation does not affect the continuation of the pumping but which must take place for the second pumping to occur. The washing machine has a horizontal perforated drum mounted in a tub and rotatable about a. horizontal axis at low and high speeds for washing and 'spin-drying. The tub is filled through a solenoid operated water valve and emptied by pump 9 with its own electric motor. The timer 12, which includes a cam 10 driven by a stepper, is energized through contacts T when closed and a resistor 13 and continues to run until a definite time has expired or a predetermined temperature or water level has been reached when the cam is stepped onto the .next position by the stepper which operates when 'resistance 13 is short-circuited. Pairs of contacts 16, .17 or 18 corresponding to times of 20 seconds, 2 minutes and 4 minutes respectively are connected in series with contacts 19, 20, 21 associated with a common contact C. If in any cam position contacts 16, 18 are open and contacts 17 closed, contact 19 engages contact C after 20 seconds but nothing happens as contacts 16 are open. However after 2 minutes, when contact 20 engages contact C as contacts 17 are closed resistance 13 is short circuited to step the cam on. If all contacts are open stepping will not take place until some predetermined condition obtains when resistance 13 will be short circuited. Contacts W in series with water valve WV are .also connected 'to a contact Z of a level responsive device 25 having a common contact A and a 'full" contact X. When the tub is empty, contacts A, Z are connected and if contacts W are closed valve WV is opened. A printed circuit has annular surface sections T, d, e, f, g, h, i, k, E and F which at various positions of cam 10 are placed in contact with bus-bar 26. When the machine is full and contacts A, X are bridged valve WV is closed and resistance 13 is short circuited through printed circuit section F so that the cam is stepped onto a further operation. At three cam positions during the programme - (18), (28) (35) (Fig. 2, not shown) if the pumping has taken place fully at the preceding position (17), (27), (34) so that contacts A-Z are bridged, then the cam is stepped straight .on to the succeeding position viz. (19), (29) or (36) and the programme continues whereas, if the contacts A-Z are not bridged the cam stops at the position (18), (28) or (35), Thus if the pump becomes stalled at any point, it will not remain energized sufficiently long to 'be damaged.