Patent GB-546385-A (GB)
Title: Improvements in or relating to power transmission devices
IPC: F16H47/08
Filed: 1941-01-04
Abstract: 546,385. Hydraulic power transmission ; clutches ; variable-speed gearing; controlling motor vehicles. EATON MANUFACTURING CO. Jan. 4, 1941, No. 146. Convention date, Feb. 20, 1940. [Class 69 (ii)] [Also in Groups XXIV and XXXI] A power transmission device which is especially applicable to driving motor vehicles is constructed with an impeller member B fitted with a series of radial vanes 15, a turbine member C formed with vaned parts 17, 18 separated by a ring-shaped member 19, and a member E formed with vanes 31, the member E being capable when the mechanism is running of being put in driving- connection with either of the members B or C when the device acts as a fluid coupling, or of being free of the same when the device acts as a fluid torque converter the member E acting as a reaction wheel in that case. The change over from one form of drive may take place automatically at a predetermined speed. The turbine C is connected to the annulus 22 of a sun-and-planet gear D, and the planet wheels are mounted in a spider member 24 splined to the driven shaft 26 from which the car is driven through a differential reverse gear F. The sun wheel 36 is attached to a tubular member 32 between which and the hub 40 of the casing A of the impeller member a coil over-running clutch 34 is arranged which selectively allows rotation of the member 32 to take place in one direction only by means of a sliding collar 47 adapted to cause one end of the coil to be held by a projection 43 on a key which slides in the member 32, or the other end to be held by a shoulder on a flange (146, Fig. 2, not shown), fixed to the collar 47. The member E thus rotates with the casing A and the device acts as a fluid coupling, or in the reverse direction when the member E acts as a reaction member. An over-running clutch 139 permits the car to drive the engine when the car's speed is greater. The sliding collar 47 is controlled by a sliding yoke member 48 operated by a spring-controlled piston 82 in a cylinder connected by a pipe 99 to an oil pump driven by worm gearing 65, 67 from the ultimate drive shaft 63 of the gearing. At a given speed the oil pressure is adequate to operate the piston 82 and thus actuate the yoke 48. The yoke 48 is held by a spring detent in adjusted position. The oil pressure can be hand-controlled by means of a byepass valve actuated by a Bowden wire 95, Fig. 5, from a lever under the steering wheel 92. The reversing gear F comprises a splined gear 57 on the shaft 26 which engages continuously two bevel gears 58, 59 rotatably mounted in a spider 60 and in mesh with a gear 62 on shaft 63. By means of a sliding yoke 77 operated by Bowden wire mechanism the spider 60 can be connected by teeth 73 to teeth 74 on the gear 57 when the gears 57, 58, 59, 62 rotate as a unit and a direct drive is obtained ; or the teeth can engage fixed teeth 75 and a reverse drive is obtained. In an intermediate position the yoke is free and the gear is in neutral. The yoke 75 is held by a catch 110 which is depressed by oil pressure to prevent actuation of the reversing mechanism while the car is running. To prevent motion of the car when the gear is in neutral a band brake 117 is operated by a vacuum motor 120 to apply the brake against the action of a spring 122. The motor 120 is controlled by a valve 129 operated by an electromagnet 130 to cause the brake to be applied upon energization of the magnet 130. The circuit to the magnet 130 is closed only when the accelerator pedal 132 is fully raised, when the ignition switch 136 is closed, and when the catch 110 is engaging the yoke 77 to hold the reverse gear in neutral position. In a modification the coil clutch 34 is arranged between the shaft 26 and the tube 32 and so serves to cause the members C, E to operate together when the device acts as a hydraulic coupling.