Patent GB-759555-A (GB)
Title: Rotary torque and speed variable transmission
IPC: F16H47/08
Filed: 1954-05-17
Abstract: 759,555. Variable-speed gearing. CARP, P. J. May 17, 1954 [May 20, 1953], No. 14339/54. Class 80(2) In a transmission including a hydraulic torque converter 18 and an epicyclic gear 22 the driven shaft 34 is rigid with the carrier 24 of the planet gears 26, a sun gear 30 on a shaft 20 is connectable to the driving shaft 10 through a clutch 14, and another sun gear 28 can be connected through a clutch 64 to the turbine member 54 of the converter 18, the impeller 52 of which is fixed to the driving shaft 10. The turbine shaft 60 has a one-way drive 62 with the shaft 20, and one-way drives 70, 72 connect a pair of reaction members 56, 58 with a shaft 68 having an arm 74 connected to a valve 76. If the clutch 64 is disengaged a brake 86 may hold the sun 28 stationary. The arrangement provides four gear ratios. First gear. The brake 86 only is engaged and the drive passes from the turbine 54 and connection 62 to the sun 30 to drive the shaft 34. Second gear. Clutch 14 and brake 86 are both engaged so that the sun 30 is driven at the speed of the driving shaft 10. Third gear. Clutch 64 only is engaged. Thus both suns 28, 30 are driven at the speed of the turbine 54 and the epicyclic gear runs solid. Fourth gear. Both clutches 14, 64 are engaged. In this gear the power from the shaft 10 is divided, part going through the clutch 14 to the sun 30 and the remainder, 60 per cent or less, through the converter 18 to the sun 28. If applied to a road vehicle means is provided to enable the engine to be started by pushing the vehicle. As shown, the output shaft 34 is connected to the sun gear 30 by a dog 44 and detent 32 and at the same time the shaft 34 is also connected to a gear 46 by a clutch 36. Gear 46 drives an oil pump 50 supplying oil to a pressure unit 16 to engage the clutch 14. Thus rotation of the driven shaft 34 is transmitted back to the shaft 10 to start the engine. The shaft 10 drives an oil pump 12 supplying oil to a control system to enable the gear ratios to be changed automatically according to speed and torque or manually. The reaction torque of the members 56, 58 acts through the shaft 68 to hold the arm 74 against a stop 90 so that the oil line 93 to the pressure unit 16 is connected to the sump so that the clutch 14 is disengaged. When the reaction torque becomes small a spring 92 moves the valve 76 to engage the clutch 14. The clutch 14 may be disengaged by a valve 104 controlling pressure fluid to a piston 94 on the valve 76. The valve 104 may be operated automatically in accordance with speed and torque or manually. When the valve 104 is closed pressure oil leaks away through a vent 96. A third valve 98 controls pressure fluid to the pressure units 84, 88 of the clutch 64 and brake 86 respectively. Each time the valve 98 is moved into either of its two positions pressure fluid is led from an accumulator 100 to the piston 94 to release the clutch 14. The time period during which the clutch 14 is disengaged depends on the volume of the accumulator 100 and the leakage rate of the vent 96. The valve 98 may be controlled by a speed governor influenced by the throttle pedal. The clutches and brake may be actuated electrically.