Patent GB-620210-A (GB)
Title: Improvements in and relating to automatic machines for washing clothes and like articles
IPC: D06F34/08
Filed: 1947-01-08
Abstract: 620,210. Washing-machines. BRITISH THOMSON-HOUSTON CO., Ltd. Jan. 8, 1947, No. 676. Convention date, Jan. 8, 1946. [Class 138 (ii)] An automatic machine for washing clothes comprises, as shown in Fig. 3, a circulating pump 65, a drain pump 71, a water supply valve 83, 86, a timer 100, a sequence control system in the form of a set of parallel circuits for the circulating pump and water supply valve and a set of parallel circuits for the drain pump and timer, a cam-controlled switch VIII for closing alternatively a circuit through either of these sets of circuits, and a second cam-controlled switch VII for closing an alternative circuit through the second set of circuits, whereby the circulating and drain pumps may be operated simultaneously. The invention is applied to a machine which is constructed as shown in Fig. 1 and comprises a basket 2 having an agitator 3 mounted therein, the agitator being oscillated during the washing operation and the basket rotated at high speed during the drying operation. The basket 2 is disposed in the upper compartment of a tub 1, being supported, together with the drive mechanism therefor, from a platform 15 in the tub. The agitator is mounted on a shaft 6 which is disposed inside a tubular shaft 5 adapted to drive the basket, the two shafts 5, 6 projecting below the basket into casing 14 enclosing the drive mechanism. This drive mechanism, includes a motor 33 adapted to drive the shafts 5, 6 through gearing 28 ... 30 and clutches 37, 38, 41, 45; the gearing is carried by a frame 16 which is secured to the shaft 5 and has a hub 18 journalled in a bearing 19 in the casing 14. During washing, the clutch parts 37, 38 are engaged, and the clutch disc 41, which is slidable on the hub 18, is disengaged from the clutch disc 45, but engaged with a brake ring 43. As a result, the gear frame 16 is held stationary, and a shaft 31 acts through the gearing 28 ... 30 to oscillate the agitator shaft. During drying, fluid is pumped continuously from a sump 50 by a pump 47 at the foot of the motor shaft and is caused to pass upwardly along grooves 55 in the motor shaft so as to disengage the clutch parts 37, 38. Fluid then passes into a bellows 46 so as to expand the same to lift the clutch disc 45 into engagement with the clutch disc 41, and, at the same time, disengage the latter from the brake ring 43. The motor drive is thus connected through the clutch parts 41, 45, and the mechanism, including the basket, rotates as a unit. The fluid supply for carrying out the latter operation is made effective by energizing a solenoid 58 so as to close a normallyopen discharge valve 57 from the pump 47. Water supply, circulating and drain means.-Hot and cold water are supplied to two thermostaticallycontrolled mixing chambers 77, 78 which are adapted to supply, respec. tively, tepid and hot water through pipes 81, 84 to the tub 1. The flow of water through these pipes is under the control of solenoids 83, 86, and the hot water pipe 84 leads to the tub through a soap box 85. A pump 65 is provided for circulating water from the platform 15 of the tub to the basket 2, the outlet pipe 68 of the pump discharging on to a screen 70 on the basket 2. A drain pump 71 is provided for discharging water from the platform 15 to a drain. Control system.-The platform 15 is fitted with water-level and overflow switches 87, 90. The switch 87 is normally closed, and is opened by a float 87a when the water reaches a predetermined level. The switch 90 is biassed to open position, and is adapted to be closed by a bell-crank lever 91 when the flow of water to a cup 92 carried by the lever is more than a certain amount; this cup 92 is positioned so as to receive water which has passed through openings 26 in the agitator post 21 or openings 4 in the basket 2 into spouts 95, 97 leading to the cup. Whenever the agitator is oscillating, the pump 65 continuously pumps water from the platform to the basket, from which it flows back to the platform mainly through the spouts 95, 97. The control circuit for the machine comprises, as shown in Fig. 3, a main timer motor 100 driving eight cams I ... VIII, which control two-position switches, and a washtimer motor 102 which drives a timer cam 101 controlling a switch 103; also included in the circuit are the main motor 33, solenoid 58 controlling the valve 57, float switch 87, overflow switch 90, tepid and hot water solenoids 83, 86, and the motors driving the circulating and drain pumps 65, 71. The timer motor 100 is connected to the mid-point of a resistance 109 so that it can be operated by cam switches IV, V, VI, VII and VIII in various combinations. In some combinations, the main motor winding 34 or the drain pump motor is connected across the supply including the resistance 109, but cannot then operate since the resistance prevents the flow of sufficient current. The main motor is provided with a starter winding 34a in circuit with a magnetic switch 108; this switch is closed by the initial current in the main winding 34, but is cut out when the motor starts to run. Operation.-The washing sequence is shown in the cam chart of Fig. 2 and is initiated by manually moving the main cam shaft to the starting position a. The cams then close contacts including the tepid water solenoid valve 83 and the circulating pump 65, and water flows into the tub until the float switch 87 opens and, by de-energizing the solenoid 83, cuts off the water supply. Prior to the opening of the float switch 87, the overflow from the basket 2 effects closing of the overflow switch 90 so as to close a circuit of the main timer motor 100 and also a circuit including the winding 34 of the motor. The motor then drives the agitator, while the pump 65 continually circulates water from the tub through the basket. If the water in the tub should fall below a predetermined level, the float switch 87 will close so as to admit additional water, and, if the water overflow from the basket should fall sufficiently, the switch 90 will open so as to stop the main motor. While at this time the drain pump motor is included in the circuit of the main timer 100, the presence of the resistance 109 will prevent the flow of sufficient current to operate the pump. At the end of this agitationsoak period, cams act to energize the solenoid 58 so that the basket is rotated at high speed, and the drain pump is set into operation. At one point during the spinning of the basket, one of the cams is effective to disconnect the drain pump and cause the circulating-pump to flush the screen 70 with water for a brief period. The cams then operate to open the drain pump circuit, close the circuit of the circulating pump, and stop the machine. The solenoid valves 83, 86 are then operated, according to the previous setting of a switch 110, to supply either hot or tepid water, or a mixture thereof, to the tub, the main timer being ineffective during this operation. Filling of the tub continues until the overflow switch 90 closes and the float switch 87 opens, upon which the agitator and circulating pump are again operated. This operation continues under' the control of the main timer for a fixed period, after which the cams effect the disconnection of the main timer and the connection into the circuit of the wash timer 101. The machine then works on the wash timer for a period determined by a previous manual setting of this timer, after which the main timer is brought back into the circuit. Just before the end of this wash-agitation period, the drain pump is again started, with the circulating pump still in operation so that the float switch 87 is soon effective to energize the solenoid 83 for the admission of tepid water for the purpose of removing " suds lock " from the space between the basket and tub. At this stage, the solenoid 58 is again energized so that the basket is rotated at high speed, and the drain pump is set into operation, except for a brief period when the circulating pump flushes the screen 70 with water. The motor and timer are then stopped, and warm water for rinsing supplied to the tub through the valve 83. A period of agitation follows, during which warm water is admitted on two occasions, and the basket is then spun at high speed; the drain pump is not in action during the latter operation so that the rinse water is not discharged to the drain. At the end of the whole cycle, the rinse water may either be left in the tub, or discharged by suitably setting the main timer dial so as to close the circuits of the drain pump and the main timer; while the motor armature will then be connected in circuit, the resistance 109 in this circuit will prevent the current being sufficient to operate the motor.