Patent GB-522265-A (GB)
Title: Improvements in or relating to gear shifting mechanisms
Filed: 1938-12-03
Abstract: 522,265. Controlling change-speed gearing. AUTOMATIC SHIFTERS, Inc. Dec. 3, 1938, No. 35322. Convention date, Dec. 13, 1937. [Class 80 (ii)] [Also in Group XXIX] Selecting and actuating mechanism for the change-speed gearing of motor vehicles comprises a low gear and reverse shift rail 14, Figs. 6 and 7, and a second speed and top shift rail 15, the two rails being coupled by a lever 16 which is adapted for actuation intermediate its length by an arm 33 on a rock-shaft 29 actuated by a vacuum motor 35. One or the other of the shift rails 14, 15 is adapted to be selectively locked by means of a rock-shaft 22, co-operating with balls 44, 45, which is actuated through a rod 120, crank 115 and rod 108 by up and down movement with respect to the steering wheel 11 of a gear selecting lever 101. The motor 35 is controlled by a control valve 49, shown in detail in Fig. 2, which is adapted to be actuated through a floating-lever 89, rod 131, crank 128 and a hollow rod 99 by backward and forward movement of the lever 101. The floating-lever 89 is pivoted at its centre on an arm 31 secured to the actuating rock-shaft 29 so that a follow-up movement is obtained between the valve member 52 and the piston of the motor 35. The valve 52 has two control heads 53, 54 which control the suction to conduits 72, 73 leading to the ends of the motor cylinder from a conduit 58 connected to the engine intake manifold and opening into the space 55 between the heads 53, 54. A diaphragm 75 is subjected to the pressures at the two ends of the motor cylinder so that a "feel" proportional to the power effort to shift the gears is obtained on the lever 101. In the event of the vacuum supply or the motor failing the actuation of the gears may be effected manually by the lever 101 by reason of discs 83 on the valve member 52 abutting against the walls of the diaphragm chamber 76 and thus fixing the lower end of the floating-lever 89. In operation to select low gear or reverse from the neutral position the lever 101 is first lifted upwardly, which results in the locking of the second and high gear shift rail 15 by the ball 45, and then moved rearwardly or forwardly for low or reverse gear respectively which movement operates valve 52 to open one of the ends of the motor 35 to the suction and the other to atmosphere, through ports 63 or 64, and so effect the desired shifting operation by means of the rock-shaft 29, arm 33 and lever 16. To change to second or top gear the lever 101 must be first brought back from its forward or rearward position to its central position, which movements results in actuation of the motor 35 to neutralize the gears, from which it will be moved downwards by a biassing spring 119' to release the shift rail 15 and lock the low and reverse gear shift rail 14. Forward or rearward movement of the lever 101 will bring about the operation of motor 35 for second or high gear respectively. In a modified arrangement of the lever control mechanism the lever 101 operates a single rod in both rotary and axial movements instead of the double rod arrangement described. The lever may also be guided in an H-shaped gate but this is not necessary since the mechanism itself inherently provides an H-shaped path of movement.