Patent GB-901073-A (GB)
Title: Power transmission system
IPC: B61J3/12
Filed: 1959-10-27
Abstract: 901,073. Hydraulic transmission of power; hydraulic apparatus. MOVET INDUSTRIES Inc. Oct. 27, 1959 [Oct. 28, 1958], No. 38341/61. Divided out of 901,072. Class 69 (2). An hydraulic transmission for a railway car mover 10, Fig. 2, comprises a plurality of fluiddriven rotary motors 42 having rotary controlvalves, each motor having an input shaft 184, Fig. 11, for driving its control valve, and a transmission control 38 having an endless flexible element 44 operated by the control and connected to drive the control valves to synchronize the speed and direction of rotation of the motors. The motors, which may be of the type having inner and outer lobed or toothed elements differing by one in the number of lobes or teeth, are supplied with fluid pressure from a line 172 connected to a rotary pump 40 driven by a prime mover 28, such as an internal combustion engine, the engine also being connected by a belt 36 to the transmission control 38. The control has levers 82, 84 which are connected by flexible cables 86 to a control element 94 adapted to be held in the hand and adjust the speed and direction of the element 44 which is in the form of a chain running over toothed pulleys on the input shafts 184 of the motors to vary their speed and direction of rotation. The output shafts 186 of the motors carry gears arranged around a sun gear 188 having a chain connection 48 to a shaft 50a secured to the driving wheel 118 of the car mover. The line 172 from the pump is connected by a line 174 to the left-hand motor 42, by a valve 190 to the centre motor, and by a valve 192 to the righthand motor. When relatively low pressure exists in the line 172, such as when the car mover is travelling under light load, all the output from the pump passes to the left-hand motor which rotates at high speed and low torque to drive the wheel 118. A higher pressure in the line 172 as a result of increased load causes the valve 190 to open and fluid to be supplied to the left-hand and middle motors so that the wheel is driven with a higher torque but at a lower speed. At a higher pressure still in the line 172, the valve 192 opens so that fluid is supplied to all three motors so as to drive the wheel with maximum torque but at a lower speed. Excess pressure in the line 172 is relieved by a relief valve 176. The car mover has frame parts 52, 54, Fig. 2, which can be urged together by piston-andcylinder devices 56 so that the wheel 118 on the part 52 and a second freely-rotatable wheel 118 on the part 54 grip the wheel 18 of the car. The car mover is also provided with wheels 62 which are used for transporting the car mover and can be retracted when required by piston- and-cylinder devices 58, Fig. 12. The devices 56, 58 are selectively operable by actuation of valves 196, 198 connected to a manuallyoperated pump 64 mounted on the car mover, the pump preferably being of the type having a high speed, low pressure output which changes to a low speed, high pressure output according to the pressure demand. When the valve 196 is positioned so that the devices 58 are operated to raise the wheels 62, a needle valve 199 controls the rate at which the wheels are raised. In the alternative operating position of the valve 196, the pump 64 delivers fluid to the motor to lower the wheels through a pair of check valves 200 which serve to lock the devices in position and are released when the wheels are to be retracted by fluid pressure in a branch line 202. The devices 56 are similarly controlled by the valve 198 and have check valves 204 for locking them in position, the valves being released by fluid pressure in a branch line 206.