Patent GB-1159960-A (GB)
Title: Hydraulic Transmission
IPC: D06F37/30
Filed: 1966-12-06
Abstract: 1,159,960. Hydrostatic transmissions; positive clutches. BORG-WARNER CORP. 6 Dec., 1966 [13 Dec., 1965 (2)], No. 54596/66. Headings F2C and F2D. [Also in Divisions D1 and F1] In an hydrostatic transmission, particularly in an automatic clothes washer, a reversible, variable-displacement, sliding vane pump 20 selectively alternatively energizes, through a line 40, a rotary hydraulic motor 24 (for spinning) or, through a line 41, an oscillatable hydraulic vane motor 22 (for agitating) in dependence on the pump rotational direction. The pump 20 is driven by an electric motor 13 which also drives a pump 14 for re-circulation of water in a clothes basket 11. An "agitate-off-spin" selector switch 16 (e.g. timer actuated) determines the rotational direction of the pump 20, the " spin " lead 37, 38 being broken by opening of a switch 31 on raising of the basket lid 30. The pump 20 comprises a sliding cam ring 55 and rotor 58 having vanes (59) sliding in slots (59a). A port plate (62) adjacent the rotor is so ported as to hydraulically balance the vanes so that they remain in engagement with the cam ring. The latter is leftwardly urged, to reduce displacement, by a spring 57 and is rightwardly urged, to increase displacement, by one of control means 90, 91 respectively for spin and agitate. The control means 90, 91 comprise three-part tappets acted on by manually operated levers 116, 117 through cams 92, 93. The levers 116, 117 may sweep semicircular speed-indicator plates (Fig. 5, not shown). The three parts of each tappet have longitudinal pin and slot lost-motion connections. On energization, say of the " spin " line 40, the centre and right hand tappet parts of the control means 90 are hydraulically spread so as to render the tappet effective in moving the cam plate 55 in response to movement of the lever 116, whereas the tappet 91 remains in a collapsed, ineffective, condition. Springs 108 separating the centre and left hand tappet parts allow decrease of pump displacement in the event of excess pressure. Since agitation requires the greatest torque and hence greatest pressure, the spring 108 and hydraulic characteristics of the control means 91 are designed to allow a greater pressure than that allowed by the means 90. The agitate motor 22 comprises an oscillatable vane 123 to the opposite sides of which pressure liquid is alternately fed through a reversing valve 121. The distributer piston 126 of the latter is actuated, hydraulically at the ends of the vane stroke, by pressure and exhaust of liquid through ports 151, 148 in the vane and suitably positioned ducts 149, 150 in the motor body. In the modification of (Fig. 10, not shown), the agitator stroke is varied by additional motor body ducts (136), (137) which are rendered effective to reduce the stroke by a manual control valve (235). A clutch 23 is provided between the vane 123 and the agitator 12 so that the latter may rotate freely and follow the clothes basket during spinning. The clutch 23 comprises a spring-return piston member 174 slotted to receive drive lugs 171, 172 of the agitator shaft 160 and axially movable by pressure in the " agitate " line 41 to engage dog teeth 179 thereon with mating recesses 180 in the hub of the vane 123. The spin motor 24 comprises an inner, toothed, rotor 186 fast with the clothes basket 11 and co-operating with an outer, recessed, rotor 185, motor driving pressure being admitted from the "spin" line 40 and exhausted through a line 42. The outer rotor has peripherally spaced recesses 202 to accommodate the end 199 of a spring-returned piston 198 of a lock 25 which is actuated to lock both rotors by pressure in the " agitator " line 41 so that during agitation the clothes basket is stationed. The spin motor exhaust line 42 includes a braking valve 26 having a spool 221 which is rightwardly urged by pressure in the " spin " line 40 to allow unrestricted exhaust from the spin motor and is leftwardly urged by a spring 222, when the " spin " line is de-energized, to direct the motor exhaust through a restriction 229 so as to hydraulically brake the clothes basket.