Patent GB-687060-A (GB)
Title: Hydraulic controls for automatic washing machines
IPC: G05D23/13
Filed: 1947-10-21
Abstract: 687,060. Washing-machines. ROBERTSHAW-FULTON CONTROLS CO. Oct. 21, 1947. [Nov. 27, 1946] No. 28149/47. Class 138 (ii). [Also in Group XXIX] A hydraulically-controlled automatic washing-machine includes a number of hydraulic pressure motors for actuating the various parts of the machine, and a motor driven timing mechanism which operates a pilot valve to actuate the various hydraulic pressure motors in the desired sequence, the timing mechanism being arranged to initiate operation of a motor which effects washing and on completion of the cycle to terminate operation of such motor and of the timing motor. Fig. 1 shows the general layout ; 20 is an electric motor driving through reduction gearing 18 the timer unit 17 comprising a hydraulic distributing valve, whereby mains water pressure derived from the cold water supply 16 through pipe 202 is distributed in the desired sequence to actuate (i) through pipe 203, the hydraulic motor 160 which controls the main electric motor, (ii) through pipe 204, the hydraulic motor 159 which controls the drain valve, (iii) through pipe 80, the mixing valve 14 to adjust the thermostat therein to use cold water for rinsing, (iv) through pipe 115, the flow control valve 12, which in turn is influenced by the float valve 13 whereby the flow control valve 12 is shut when the water in the tub 10 reaches a pre-determined level. Each unit is described in turn below. Timer unit. Figs. 4 and 8 show a motordriven shaft 123 which drives through two worm reduction gears a shaft 131. Secured to shaft 131 is a disc 133 which engages between the teeth of a gear 135 rotatably mounted on the timing spindle 136, the disc 133 having an offset portion 134 so that for every revolution of the disc the gear 135 is advanced suddenly by one tooth. The gear 135 drives the timing spindle 136 through a pawl 139 and ratchet wheel 137 fast with the spindle 136, whereby the spindle 136 may be rotated manually to cut out one or more of the operations. Fast with spindle 136 is a cylindrical valve 181 having appropriately shaped ports therein to distribute hydraulic pressure in the desired sequence from the pipe 80 to pipes 202, 203, 204 and to place pipes 114 and 115 into communication with one another periodically. Any water escaping past the ports leaves the unit through drain pipe 184. The upper end of the timer spindle 138 carries a cam 144, Figs. 1 and 5, coacting with three contact arms 147, 148, 149. Arm 149 is connected in the circuit of the main motor which operates the washing mechanism, 148 in the timing motor circuit and 147 is common to both circuits. When the step 145 on the cam reaches contact arm 147 the latter moves and breaks both motor circuits to stop the machine. Manual rotation of the spindle 136 to the 'start' position allows contact arm 148 to drop down the step 145 to complete the circuit to the timing motor, whereupon spindle 136 commences to rotate and eventually starts the main motor. Hydraulic motors 159, 160. As shown in Fig. 12, each of these comprises a cup-shaped casing 161 to the open end of which is secured one end of a bellows 163 whose other end is closed by a second cup shaped member 165 sliding within the first. Member 165 serves to limit the travel of the bellows, and its contact with the interior of cup 161 may be confined to a few ridges 166 to reduce friction. Admission of hydraulic pressure to the space 173 contracts the bellows and the corresponding movement of rod 168, connected by a ball joint to the end of the bellows, is utilised to open the drain valve or to operate a clutch or brake for the main motor. Mixing valve 14. As shown in Fig. 2, the mixing valve comprises hot and cold water inlets 27, 26 communicating through ports 33, 32, controlled by a ball valve 34, with a mixing chamber 31. Chamber 31 communicates by a passage (not shown) with the space 37 from which the water, mixed to the desired temperature, flows through the outlet 85 to the flow control valve. The ball valve 34 moves between an uppermost position in which the port 32 is closed and only hot water passes into mixing chamber 31, and a lowermost position in which port 33 is closed and only cold water passes to the mixing chamber. The ball valve 34 is carried by a tube 46 whose upper end is attached to the movable end wall of bellows 44 which is secured to the lower end of a cupshaped member 41, 39. Attached to the upper end of cup member 39 is a second bellows 58 urged downwardly by spring 67 until a bridge piece 61 pressed against its movable end abuts against a collar 64 on the post 63. The space 59 between the cup member 41, 39 and the two bellows 44, 58 is filled with a thermosensitive fluid. If the temperature of the water flowing through chamber 37 is lower than the predetermined temperature, contraction of the thermosensitive fluid in space 59 causes the bellows 44 to expand under the influence of light spring 83 and the ball valve 34 is moved to admit less cold and more hot water to the mixing chamber 31. If the temperature is higher than the predetermined temperature the converse takes place ; if the thermosensitive fluid continues to expand after the ball valve 34 is fully seated, the bellows 58 contracts against the spring 67 whereby damage to the bellows 44 is prevented. The temperature of the mixed water may be varied either manually, or automatically under the control of the timing mechanism, by altering the capacity of the space 59 containing the thermosensitive fluid and this is done by raising or lowering the post 63 and so contracting or expanding the bellows 58. Manual adjustment of the post 63 is effected by moving the manual control rod 76 whose lower end abuts against the end wall 70 of cup 69 secured to the movable end of bellows 68 and which end wall is fastened to the post 63 ; thus downward movement of control rod 76 pushes the post 63 down, whilst on upward movement of control rod 76 the end wall 70 of cup 69 follows the control rod because its under face is subjected to water pressure from chamber 37 through the ports 81, such water pressure being sufficient to overcome the downward thrust of spring 71. Automatic lowering of the temperature of the water, for the rinsing operation, is attained when the distributing valve in the timer unit admits hydraulic pressure into the pipe 80 and so to the exterior of bellows 68. This counterbalances the water inside bellows 68 referred to above, and so permits the spring 71 to press down the cup 69 until it abuts the flange 54 and so lowers the post 63. The opposite sides of the ball valve 34 are subject to the pressure of the hot and cold water supplies respectively, and provision is made for rendering the ball valve free from the influence of differences in such pressures. Thus the tube 46 is sealed to the casing 26 by a bellows 48, whose effective area is the same as that of the port 32, so that variations in cold water pressure are balanced out. In addition holes 48<SP>1</SP> in the tube 46 permit the hot water pressure to be applied to the inside of bellows 48, whereby variations in hot water pressure are balanced out. Flow control valve 12. Water from the mixing valve 14, Fig. 1, passes to the flow control valve 12, which permits water to pass therethrough into the washing tub 10 until the water level therein reaches a pre-determined level, as determined by the float valve 13, but only so long as the timer unit puts pipes 114 from the float valve and 115 to the flow control valve in communication with one another. The flow control valve, Fig. 3, comprises an inlet 90 and outlet 11 to the tub, the outlet normally being sealed by a valve member 93 held down by the natural resilience of the bellows 96. The bellows has near its base a small bleed hole 98. In operation, the pressure exerted by water entering the flow control valve lifts the valve 93 off its seat and passes to the tub ; some water passes to the interior of the bellows through the bleed hole 98, but as such interior is in communication with the atmosphere through pipes 115, 114 and the port 110 of the float valve 13, no pressure build up occurs. When the water in tub 10 reaches the desired level, the float 105 rocks bell crank 106 to close port 110, whereby pressure builds up inside the bellows 96 until it equals the water pressure outside the bellows, whereupon the natural resilience of bellows 96 closes valve 93 on to its seat and stops the water flow. Flow is similarly stopped when the timer unit breaks the connection between pipes 114 and 115 and closes pipe 114. Specification 687,085, [Group XXIX], is referred to.