GB876839A - Improvements in dishwashing machines - Google Patents

Abstract

876,839. Dish-washing machines. GENERAL MOTORS CORPORATION. June 28, 1960 [July 27, 1959], No. 22606/60. Class 138(1). [Also in Group XXV] A dish-washing machine comprises an apertured spray tube 30, Fig. 1, rotated by a reversible electric motor 42 which also drives an impeller 152, Fig. 11, within a sump housing 136, the impeller when rotated in one direction pumping liquid to the spray tube 30, and when rotated in the opposite direction pumping liquid to a drain 168 and also functioning as a waste communicating device, a valve 174, 178 being provided which in one position prevents flow to the drain 168 and in another position prevents flow to the spray tube 30. Before the dishes are placed in the machine the strainer 126 above the sump is raised and retained in an upper position by spring tabs 132 on the tube 30, whilst waste is scraped from the dishes into the sump, and the strainer is again lowered. The machine is then operated under the control of an electrical timing mechanism 200 which first opens a solenoid valve 216 to admit water into the washing chamber through a pipe 218, and energizes the motor 42 to rotate the impeller 152 in a direction such that it co-operates with the edges of the apertures 150 in a shoulder ring 144 to function as a waste communicating device. In this direction of rotation the spray tube 30 raises, through a nut 190 secured thereto, a screw 182 which is restrained from rotation and carries the valve members 174, 178. The member 174 is thus raised to close the inlet-end of the spray tube 30, and the member 178 is lifted to allow the liquid containing the comminuted waste to pass to the drain 168. After a predetermined period the timing device 200 reverses the rotation of the motor 42 and of the spray tube 30 to lower the valve members 174, 178, thus closing the entrance to the drain 168, whilst the valve 216 remains open for a time sufficient for the supply of the required amount of washing liquid, to which detergent may be dispensed by an automatic device during said time. After closure of the valve 216 the motor 42 continues to rotate the impeller 152 to circulate the washing liquid through the rotating spray tube 30, the filter 126, and the sump housing 136. The washing cycle is terminated when the motor 42 is again reversed to raise the valve member 178 to allow the washing liquid to pass to the drain 168. A rinsing cycle may then be initiated, followed by a drying operation effected by an electric heater (not shown) within the washing chamber. Arrangements for hingeing the doors of the cabinet of the machine are described (see Group XXV).