Patent GB-410314-A (GB)
Title: Improvements in and relating to driving mechanism especially such as is employed formotor vehicles
IPC: F16H61/02
Filed: 1933-04-29
Abstract: 410,314. Hydro-mechanical variablespeed gearing. KACER, B., and NOHEL, M., 30, Smecky, Prague. April 29, 1933, No. 12524. [Class 80 (ii).] Driving gearing particularly intended for motor vehicles comprises epicyclic gearing for transmitting motion from an engine shaft to a driven shaft, a first pump system connected to the annulus of the epicyclic gear, a second variable-delivery pump system connected to the first and acting as an hydraulic motor on the driven shaft, and controlling-means for the hydraulic mechanism actuated both by the engine control means and by automatic means influenced by the pressure in the hydraulic mechanism. In the construction shown in Fig. 1, an engine 12 drives the sun pinion 15 of an epicyclic gear train, the planet pinions 16 being mounted on a carrier fixed to the driven shaft 19, and the annulus 17 driving an hydraulic pump 21 connected by pipes 23, 27 to a pump or motor 25 on the shaft 19. The output of the pump is varied by means of rods 29, 80 and these are controlled partly by a pedal 34 and partly by a piston 48 operated in accordance with the pressure in the pipe 23. The pedal 34 also controls the engine throttle by a rod 81 and a reversing gear 20 by a rod 82. With the pedal 34 in its neutral position and the engine 12 running at idling speed the annulus 17 and the pump 21 are set for zero output and rotate idly, the planet carrier being held stationary by the resistance of the driven shaft 19. When the pedal is rotated to increase the engine speed a lever 38 pivoted at 41 is raised and by means of a rod 39 raises one end 32 of a floating lever 31 which rotates about its other end 40, thus increasing the output of the pump 21 which then acts as a brake on the annulus 17 and causes the planet carrier 18 and shaft 19 to rotate. The increased pressure in the pipe 23 acts on the piston 48 which rocks a lever 43, 52, the motion of which is transmitted through levers and linkages to a rod 76 which (1) raises the end 40 of the floating lever 31 and thereby reduces the output of the pump 21, and (2) rocks a lever 79 pivoted at 78 and thereby pulls a rod 80 and increases the output of the pump or motor 25. The result is that for a constant engine speed the shaft 19 and the annulus rotate at speeds depending on the resistance of the shaft, the pump 21 being driven at a rate corresponding to the difference in speed between the shafts 13 and 19 and the energy used by the pump being utilized to drive the shaft 19 through the motor 25. In the construction shown in Fig. 4 a single driving shaft 13 drives two shafts 19 through independent epicyclic gears 14 and pumps 21, 25, a differential gear being thus dispensed with. The epicyclic gears and pumps are each controlled by a separate lever 38 through a link 37. The pumps 25 are situated on the driving shaft 13 in this construction. This arrangement may also be adopted with a single epicyclic gear and two pumps otherwise similar to the construction shown in Fig. 1. In this modified arrangement the shaft 19 may be driven in either direction by the shaft 13. For this purpose the pump 21 is not adjustable and the pump 25 has an adjustable output. If the output of 25 is adjusted to less than that of 21, the latter will be braked, the annulus 17 will slow down and the shaft 19 will be driven in a forward direction. If, however, the output of 25 is increased beyond that of 21 the speed of 21 and the annulus 17 will be increased and the shaft 19 will rotate in the reverse direction.