Patent GB-590899-A (GB)
Title: Improvements in apparatus for the automatic control of the various stages of the washing process in a washing machine
IPC: D06F34/28
Filed: 1944-08-11
Abstract: 590,899. Washing-machines. BRAITHWAITE & SON, ENGINEERS, Ltd., I., and BANKS, C. A., PRITCHARD, J. C., and BANKS, G. E. (Representatives of BANKS, W.). Aug. 11, 1944, No. 15315. [Class 138 (ii)] In apparatus for automatically controlling a washing process in a machine, of the kind in which a sequence of stages each comprising a series of operations is carried out under the control of a time element by means of a rotary shaft carrying adjustable cams for actuating the supply and drain valves of the machine through relays, each operation of a stage is performed by one of a number of sub-units, the action of each subunit is predetermined by the manual setting of selector switches mounted on a plurality of panels, one for each stage, and the selected sub-units are rendered successively operative by the rotary cam shaft. Machine construction and operation. The invention is described with reference to a washing-machine W, Fig. 1, of the kind in which a washing cylinder rotates on a horizontal axis within an outer casing. The process to which the load in the cylinder is subjected is divided into eight stages, each subdivided into four sub-stages under the control of a master cam shaft B<3>, Fig. 4, which receives four step-by-step rotations each of 90 degrees, during each stage of the process. The actual operations of the machine (e.g., entry and draining of water, with or without introduction of detergents, heating of water &c.), and the timing during each stage are controlled by manually pre-set selector switches C<2>, J<3>, J<8> &c. Figs. 1 and 3, on that one of a series of panels A'-A', Figs. 2 and 3, corresponding to the stage ; whereas the sequence of selected operations within the stage is controlled by the cam shaft. Each panel carries a similar set of selector switches and is mounted, in common with the other panels on an octagonal framework H<5> rotatable through a Geneva movement H<7>, H<8> by a motor H<1> to bring each panel successively into view . beneath a window A<11>, in which position it registers with a contact board A<14> wired to the main circuits of the machine. Sequence of operations. The sequence of operations in each of stages 1-7 is similar. In the first sub-stage, a switch B<5> is closed by a cam on cam shaft B<3>, Fig. 4, to open a valve C<5>, Figs. 1 and 2, and admit water to the machine to a level controlled by selector switch C<2> on the effective panel A. The temperature of the water admitted is regulated by a mixing valve D', Fig. 4, under the control of a selector switch D<2> also on the effective panel. When the water in the cylinder reaches the required level, relay B<2> closes the circuit of motor B<1> and the cam shaft is rotated through 90 degrees to open switch B<5> and close the water valve. In the second sub-stage, a cam-operated switch B<7> is closed to admit steam through valve E' into the water in the machine. The steam valve closes when the temperature of the water reaches that selected by the setting of a switch E<2> on the effective panel. After a period, predetermined by a selector switch F<2> on the effective panel, acting in conjunction with the timing device F' the cam shaft rotates through a second 90 degrees to open switch B'. In the third sub-stage a switch B" is closed to open a drain valve, and a reset shaft B<15> is oscillated to restore timing device F' to zero and return the mixing valve D<1> to "cold" position. When the machine is empty, the cam shaft makes its third 90 degrees rotation to open switch B" and close the drain valve. In the fourth sub-stage, a switch B<13> is closed to initiate the fourth rotation of the cam shaft, which thus completes its revolution, and at the same time starts motor H<1> to bring the next selector-switch panel into effective position. Weighted quantities of detergents such as soap, soda, meta-silicate, bleach and blue, may be admitted from storage tanks J'-N' during each stage under the control of quantity selector-switches J<3>-N<3> on each panel. The time in the stage at which the detergents are admitted is determined by the setting of time switches J<8>-N<8>, also on the panels. The process ends on the completion of the second sub-stage of stage 8 with water in the machine. The water may be allowed to remain in the machine for the first stage of the next process or may be allowed to drain before that stage begins, in accordance with the setting of a switch R<3>, R<5>, Fig. 6 (not shown) on the eighth panel. If it is desired to omit any one of stages 1-7, a switch R<1>-R<4>, on the corresponding panel is moved to the right from the position shown in Fig. 4. To repeat a stage or stages, a switch F on the appropriate panel is moved to " on " position, thereby arresting the process at the end of the stage with the water in the machine and energizing a signal lamp or bell F'. A reversing switch H<3> for the motor H<1> is then operated to move the panel assembly backward one or more stages. Admission of water, controlling. The means for controlling the depth of water in the machine for each stage comprises a float C', Fig. 4, adapted to rise and fall in a chamber C<14>, Figs. 1 and 2. As this float rises it closes pairs of contacts C<1> in turn, until the pair selected by the switch C<2> on the operative panel is reached, when a circuit is completed to close the water admission valve C<5>. The float may be heavy and supported by a tension spring. Initial temperature of water, controlling. The temperature of the water admitted through the valve C<5>, Fig. 1, at the beginning of each stage, is controlled by a mixing valve D<1>, Fig. 4, set in accordance with a selector switch D<2> on the respective panel. The spindle of the valve is rotated by a motor D<3> until an arm D on the spindle contacts that one of a series of studs corresponding to the setting of the switch D', when the circuit to the motor is broken. In the third sub-stage, the reset bar B<15> throws over a reversing switch D<4> for the motor, which restores the mixing valve to " cold " position, the motor circuit being broken by the arm D opening a switch D'. Final temperature of water, controlling. In the second sub-stage steam is admitted to the machine through a valve E<6>, Fig. 1, or the temperature of the water raised by an electric immersion heater or other means. The indicator arm of a distance thermometer E<1>, Fig. 4, having an element E<5>, Fig. 1, immersed in the water, rotates as the temperature rises until it contacts a stud corresponding to that selected by the selector switch E<2> on the operative panel, when a relay E<3> is energized to close the steam valve. Duration of washing process. controlling. In the second sub-stage, a synchronous motor F<3>, Fig. 4, is energized and, through a ratchet mechanism and clutch, rotates an arm F<1> over a ring of contact studs, at slow speed, until it reaches the stud selected by the switch F<2> on the effective panel. The circuit thus made is operative to initiate the third sub-stage and either to open the drain valve or to actuate a signal. Upon movement of the reset bar B<15>, the clutch F<5> is broken to allow the arm F' to return to zero under the action of a spring. Drainage of water controlling. When the machine is empty, the float C<4>, Fig. 4, or, as shown, a counterweight G', therefore, closes a switch G<2> to close the drain valve. A dash-pot or delay-action switch may be provided to ensure that the emptying is complete before the drain valve closes. Admission of detergents, controlling-1st embodiment. The machine is provided with five similar units J-N, Figs. 1 and 4, for the admission of weighed quantities of different detergents or other substances in solution or suspension. As shown in Figs. 4 and 4A, the unit for the introduction of blue into the machine comprises a supply tank N<5> communicating with a weighing- tank N' through two valves n<7>, N<7>, arranged in series, of which the upper n' is controlled by a solenoid N<6> and the lower by a float. Both tanks may be equipped with heating coils and/or agitators. The weighing-tank is. carried by a lever supported at its free end by a spring balance N<2>, the pointer of which is replaced by a contact arm n rotatable over a series of studs n'. Detergent flows into the weighing tank until the tank is full, when the supply is cut-off by float valve N<7>. In this condition the arm n occupies the " zero " position shown. At the desired time in the stage, predetermined by the selector switch N<8> on the effective panel, a relay N<10> is energized, thus switching into circuit the motor of a pump N<4> which feeds detergent from the weighing-tank to the machine. At the same time, the valve n<7> is closed by its solenoid N<6>. The pumping of detergent into the machine continues until the arm n of the spring balance contacts that stud n' which corresponds with the setting of the quantity selector-switch N<3> on the panel. A relay N<9> is now energized to break the circuit to relay N<10>, thus stopping the pump and opening the valve n' to allow detergent from the supply tank to flow into the weighing-tank. The circuits controlling the time of admission of detergents include switches B<9>, B<17> actuated by cams B<8>, B<16> on the main cam shaft, and a contact arm F<9> which moves in step with the timing- arm F' controlling the duration of the washing process, the arrangement being such that detergents can be admitted with the water, or at any desired period after the admission of water. To prevent repeat operation of the pump, the relay N<9> is of the reset type and is mechanically restored by the reset bar B<15> during the third sub-stage. Detergents may be admitted under -manual control by depressing a push-button N". Admission of detergents, controlling-2nd embodiment. In a modification, Fig. 5A, the weighing-tank N<1> is suspended directly from the spring balance N<2>, and the feed from the weighing-tank to the machine is by gravity