Patent GB-1124090-A (GB)
Title: Pneumatic speed control means and method
IPC: D06F37/30
Filed: 1966-01-31
Abstract: 1,124,090. Washing machines. ROBERTSHAW CONTROLS CO. 31 Jan., 1966 [23 Feb., 1965], No. 4237/66. Heading D1A. In a washing machine, a programme member movable by a timing motor transmits a pre-selected pneumatic signal to actuate an actuator to such an extent at a predetermined time that the speed of a variable speed drive for part of the machine is altered by a preselected amount. The programme member comprises a flexible reading sheet 35 carried by porous resilient material attached to a rigid backing 37 and having a plurality of channels 36 which bridge two or more of the ports 12, 13, 14, 23<SP>1</SP> 27, 28, 29, 30, 31, 32, 33 and 34 in the reading head 11. Sheet 35 also has apertures which, when aligned with a port, connect it to the atmosphere. Port 12 is connected to the vacuum control chamber 15 of a manually adjustable vacuum regulator 16 which controls the wash speed of the agitator. Port 13 is connected to pneumatic actuator 20 and port 14 is connected to the chamber 21 of vacuum regulator 22 which controls the spin-drying speed as selected by knob 77. Chamber 21 is connected to port 23<SP>1</SP> of head 11 which is also connected to water level control 26 which connects vacuum line 19 to port 25 when the water level falls below a desired value. Motor 40 rotates in one direction when actuator 41 causes transmission 42 to operate the agitator and in the opposite direction when actuator 43 causes transmission 42 to rotate the basket for spin drying. The shaft of motor 40 carries a variable pitch pulley 43, formed by movable sheaves 44, 45. Pulley 43 drives a belt 47 which passes round a pulley 48 on transmission 42 and an idler roller 53 carried on a lever 49 operated by actuator 20 to reduce the tension in the belt and allow the pitch of the pulley to increase. Regulator 22 (identical with regulator 16) comprises cup-shaped housings 61, 62 sandwiching the outer periphery 63 of a flexible diaphragm 64 therebetween to form chambers 21, 65 connected respectively to port 14 and to the atmosphere. Conduit 24 connects port 23<SP>1</SP> to a tubular member 68 whose open end 69 projects into chamber 21 and can be closed by diaphragm 64. End 69 projects through an opening 70 in a member 71 biassed into engagement with diaphragm 64 which has an aperture 73 offset from end 69 and is biassed by a spring 74 engaged by plate 75 adjustable by knobs 77. The chamber 15 of regulator 16 is connected to port 12 so that chambers 15 and 21 may be connected by blisters 36 to port 13 which is connected to actuator 20. Actuator 20 is also connected to unbalance control valve 80 which is mounted on the machine frame. In operation, the wash speed is set by knob (78<SP>1</SP>) of regulator 16, the spinning speed by knob (77) of regulator 22 and the water level and temperature are selected by knobs (88), (89) and knob (90) is set for the required programme Fig. 4 (not shown). Knob (90) is then pulled to close switch 91 and place pump 18 and motors 39 and 40 across leads L 1 , L 3 , motor 39 driving programme member 35, 36, 37. During washing, regulator 16 controls pulley 53 and hence the agitating speed according to the setting of knob 78<SP>1</SP>. During spinning, regulator 22 controls pulley 53 according to the setting of control knob 77. In the event of excessive vibration valve 80 will be opened to reduce the vacuum in bellows 20 and reduce the speed of pulley 48. In a modification, Fig. 6, the idler roller 92 is carried on one end 92 of a pivoted lever 93 which the bellows 20 is connected which as a vacuum is applied causes the diameter pulley 43 to be reduced. Bellows 20 is connected as before to regulators 16 and 22. In another modification Fig. 7, motor 40 is mounted on a frame 97 to which is pivoted a lever 98. Mounted between frame 97 and lever 98 are a bellows 20, a compression spring 102 and sheaves 44, 45 so that application of a vacuum to bellows 20 increases the pitch of pulley 43. The tension in the drive belt is maintained by a spring biassed idler pulley. In a further modification. Fig. 9, the motor 40 is carried on a movable frame 109 and is biassed by spring 115 away from pulley 48 so that belt 47 tends to separate sheaves 44, 45 and drive pulley 48 at its minimum speed. When one of the regulators 16 or 22 is connected to bellows 20 it moves a lever 113 to press sheave 44 upwards and increase the speed at which pulley 48 is driven.