Patent GB-713225-A (GB)
Title: Improvements in and relating to clothes washing machines
IPC: D06F37/30
Filed: 1952-05-19
Abstract: 713,225. Operating friction clutches BRITISH THOMSON-HOUSTON CO., Ltd. May 19, 1952 CMay 17, 1951], No. 12604/52. Class 80 (2) [Also in Group VIII] In a washing machine comprising a spin basket 4 provided with an agitator, an electric motor 15, a gear train 39 for the agitator, hydraulically iactuated friction clutch means for ensuring operation of the agitator for washing or rotation of the spin basket for centrifugal drying, and a source of pressure fluid for the actuation of the clutches, the clutch means comprises a hollow piston 46 in which a main clutch plate 25 driven by the motor 15 is arranged to be movable under the action of the pressure fluid to engage a clutch face on an inner surface of the piston 46, this piston being connected to a shaft 41 of the agitator gear train and being subjected to the pressure prevailing in a space 60 defined by a frame 28 which forms a rigid structure with a casing 27 for the gear train and is drivingly connected to the spin basket, friction surfaces being provided on the piston 46 and frame 28 for coupling the piston to the frame, so that the main clutch plate 25 in one position of the frame drives the shaft 41 of the agitator gear train while the frame is held stationary by a brake 31, and in the other position of the frame the brake is released and the basket is rotated together with the frame and agitator gear train. An eccentric pump, Fig. 3 (not shown), in a housing 19 and driven by the shaft 18 of the motor 15 pumps oil through passages 67 ... 70 to the inside of the piston 46 and forces a cylindrical member 24 downwardly. This produces driving engagement between the bottom of the hollow piston 46 and clutch facing material 26 on the main clutch drive plate 25 which is constituted by a flange on the member 24. The member 24 has an internal gear 23 engaged by a pinion 22 on the shaft 18. The piston 46 has an upper plate 48 secured to the shaft 41 which carries a pinion 44 connected to an agitator shaft 45 through the gear train 39 which may be as described in Specification 625,324. Thus when the motor 15 is operating, an oscillatory motion is imparted to an agitator (not shown) in the basket 4, unless a valve plunger 79 is held open against the action of a spring 81. To change from washing to spin-drying, a solenoid is energised to retract the plunger 79 and allow oil to be pumped through passages 65, 66 to the chamber 60. The piston 46 is recessed at its periphery to accommodate a pair of split ring segments 57 which are driven by pins, Fig. 6 (not shown), on the piston 46 and thrown outwardly by centrifugal force to provide a rotating seal. The first result of opening the valve 79 is to relieve the pressure within the piston 46 so that the agitator drive stops. As pressure builds up in the chamber 60 the frame 28 and gear casing 27 are moved upwardly so as to release the brake 31 from the brake surface 32 on a frame 11 supporting the motor 15. Further upward movement of the frame 28 causes engagement of clutch faces 61, 62 so that when pressure again builds up within the piston 46 forcing the main clutch plate 25 downwardly, the frame 28, a gear casing 27 and the basket 4 will rotate as a unit. A spring closed ball valve 76 between the passages 67, 68 is arranged to prevent oil being again pumped to the piston 46 until the pressure has exceeded the value needed to disengage the brake 31, 32 and engage the spin clutch 61, 62. The valve 76 also ensures that the motor 15 comes up to speed before any load is placed on it at the beginning of the washing operation. Motor overload protection is afforded during the spin drying operation by means of a valve 83 carried on an extended arm portion 95, Fig. 5, of a plate 94 pivoted at 91 to an arm 90 forming part of a plate 89 which is rigidly mounted on a collar 84 secured to the shaft 18. Centrifugal force on a weight 97 screwed to the plate 94 keeps the valve 83 pressed against a valve seat 86 to close passages 87, 88 in the shaft 18 and collar 84 respectively. 'Under overload conditions however, the motor 15 rapidly decelerates and a spring 93 unseats the valve 83 so causing oil to be bled from the passages 68, 87, 88 to the casing 6. The resulting decrease in pressure within the piston 46 allows slipping of the clutch plate 25 and the motor is consequently partly relieved of its load. By alternate engagement and disengagement of the clutch 25, 46 the basket 4 will be gradually brought up to running speed without stalling of the motor. A balancing weight 99 is screwed to the plate 89. Passages 101, 102 prevent pressure building up beneath the clutch plate 25 and the piston 46. The pressure in the chamber 60 is relieved after the spin drying operation by the gaps in the sealing ring 57 and an opening 103 in the bottom wall of the gear casing 27. A spring-closed ball valve, Fig. 3 (not shown), prevents excess pressure in the system. Lubrication. The pump in housing 19 supplies oil through passages 68, 73 to lubricate a bearing surface 21, and through passages 66, 107 to provide lubricant between the piston 46 and upper surface of the frame 11. Oil from within the piston 46 passes through passages 111, 108, 109 and a peripheral groove 110 in the shaft 41 to lubricate the bearing surface between shaft 41 and the gear casing 27. A passage 112 leading from the groove 110 supplies lubricant for the gear train 39 within the casing 27. A peripheral groove 75 in the member 24 and connecting passages 69, 70 also acts as a lubricating passage for the member 24. Specifications 625,325, 646,403 and 648,719, [both in Group VIII], also are referred to.