Patent GB-1008940-A (GB)
Title: Improvements in change-speed gear-boxes
IPC: F16H63/20
Filed: 1963-08-15
Abstract: 1,008,940. Change-speed and clutch control. HUMBER Ltd., and R. K. HODKIN. Oct. 2, 1964 [Aug. 15, 19631, No. 32368/63. Headings F2D and F2L. A change-speed control for use in a motor car comprises a gear-changing means on a sleeve 30 splined for rotation with but axial movement along a shaft 28, driven in either direction through a slip coupling by an electric motor or a limited angular motion, a cam pin 37 and grooves 40, 41 coacting to effect axial selecting movement of the sleeve 30 coincident with its rotation. In one form, the gear-changing member consists of teeth 15, 16, Figs. 1, 2, on the sleeve 30, engageable with notches 24, 25 in three shoes secured to parallel-arranged striker rods 10-12 controlling the establishment of the ratios in a four-speed and reverse synchromesh change-speed gear. In another form, the teeth 15, 16 are replaced by a camplate 84, Fig. 4, having a slot 85 engaged by a follower 86 on an arm 87 turning a lever 80 to slide the striker rod 11 &c. The cam-pin 37, Fig. 1, is controlled by a solenoid 36. Fourth ratio is established merely by rotating the shaft 28 clockwise, so that the tooth 15 engages the notch 25 and slides the striker rod 10. Third ratio is established by rotating the shaft 28 anti-clockwise, sliding the rod 11 the other way and moving the tooth 16 to the position marked X. Second is established by operating the solenoid 36 to engage the cam-pin 37 in the groove 40, and then rotating the shaft 28 anti-clockwise. During the first part of the rotary motion, the sleeve 30 and the tooth 16 restore the striker rod 11 to its neutral position. The cam-pin 37 then enters an oblique part B of the cam groove 40, so that continued rotation slides the sleeve 30 axially. The tooth 16 then enters the shoe 18 of the rod 10, which is slidden to its third ratio position. To establish first, the shaft 28 is turned in clockwise direction while the cam-pin 37 is withdrawn, and the rod 10 is slidden in the opposite direction. To establish reverse, the cam-pin 37 is engaged with the groove 41, and on rotation of the shaft 28 the sleeve 30 is slidden further along to engage the teeth 15, 16 with a shoe 17 controlling the striker rod 12. The motor is controlled by a circuit 101, 102, Fig. 3, interconnected with a circuit 100 controlling an electromagnetically - operated main clutch and including the following components. An input-driven pump operating pressure-responsive switches or a transistorized control circuit (not further described) effects speed-sensitive operation of switches GOVI 1 , GOVI 2  &c. GOV 4 . A rotary switch operable by the car driver actuates contacts 110, 111 and has four positions: " Start," in which the engine starter is engaged; " Free," in which the main clutch is disengaged; " Drive," in which the clutch and gear control circuits are operative; and " Hold," in which the main clutch is held engaged for push starts &c. Four pushbuttons are also provided, labelled " Automatic," " Manual," " Hill Start " and " Re- . verse," and control switches <SP>P</SP> auto, <SP>P</SP>1 man, <SP>P</SP> 2 man, <SP>P</SP> hill start, and <SP>P</SP> revs, respectively. A three-position switch controls switches M-up and M-down, and is operative to effect manual up and down shifts. The opposite-polarity windings of the motor are selectively energized through a bi-stable RB switch RB2 controlled by a relay - to effect 2 rotation of the shaft 28 &c. By actuation of the " manual " push-button, the switches <SP>P</SP>1 man, <SP>P</SP>2 man are closed and the switches M-up, M-down are then operated manually to establish up and down shifts, respectively. By actuation of the " automatic " push-button, the switch <SP>P</SP> auto is closed, and shifts are effected in dependence of input speed by the switches GOV2. Accelerator pedal position modification of the shift speeds may be provided. The switch GOV1 3  prevents establishment of first RD above a predetermined speed. A relay - 2 RB controls a switch RD 2 , and the relay - 2 controls a switch RB1 to ensure sequential operation of the cam-pin solenoid 36. The switches GOV3, GOV4 prevent downshifts and upshifts, respectively, at speeds which would damage the car engine. Switches GS12, GS13 are operated by the striker rods to condition the circuit for upshift when first is established, downshifts when fourth is established &c. Clutch control.-A take-off unit 106, controlled by an engine-driven alternator &c. effects speed-dependent clutch control. A switch controlled by the accelerator pedal opens when the latter is released, for complete clutch disengagement. The characteristic of the take-off unit 106 is modified by the " hill start " push-button, so that the clutch engages at a higher speed. Above a predetermined speed, the switch GOV1 moves to cut-out the speeddependent take-off unit 106, and instead introduces a resistor circuit 107 into the clutch circuit. At less than one-third throttle settings, a resistor R 1  is in series with the clutch, to allow some slip. Above one-third throttle setting, a parallel-arranged switch shorts the resistor R 1 , for full clutch engagement. On overrun, a switch connects a resistor R 2  in the clutch circuit, for light clutch engagement to transmit engine-brake torque. Switches GSN1 GSN2 disengage the clutch and control engine speed during ratio shifts.