GB707764A - Gear selecting mechanism - Google Patents

Abstract

707,764. Controlling change-speed gearing. AUSTIN MOTOR CO., Ltd., and HOLLIDAY, R. P. M. Nov. 11, 1952 [Sept. 7, 1951], No. 21193/51. Class 80 (2) Gear preselection and engaging mechanism, for change-speed gears in automobile transmissions, comprises a latch lever 5 which, in order to effect gear preselection, is placed under load (e.g. by a control lever 9 and pivoted spring 7) to rock about an axis 4 in either of two directions from a neutral position, the latch lever being allowed to rock from the Fig. 1 to the Fig. 2 position by movement of a control device 19, Fig. 5, under the control of the main clutch, the control device then displacing the latch linearly from the Fig. 2 to the Fig. 3 position to establish the change, means, such as a fixed pin 16 in a slot 15, preventing linear motion of the latch before it is rocked. The tail 6a of the latch lever 5 is engaged by a cantilever spring 17 which tends to keep it in the central, or neutral position; the latch lever is connected to a selector rod 1 and a striker fork 2 which are moved to establish the preselected change. The latch lever is prevented from rocking'prior to disengagement of the main clutch by the double cranks 20, 211 of the control device 19 engaging cam surfaces 13, 14, Fig. 1, thereon; depression of the clutch pedal rotates the control device anti-clockwise about an axis 22 to lie against a fixed stop 23 so that the cranks are situated opposite slots 11, 12, Fig. 2, whereby the latch lever is rocked up or down, according to the direction of loading by the preselector spring 7, the slot 15 and the fixed pin 16 thus being positioned to allow linear movement of the latch lever. Release of the clutch pedal then permits a spring, or hydraulic or electric means, to rotate the control device in a clockwise direction and thus slide the latch lever 5 and striker fork 2 to the right, if crank 20 is engaged in slot 11, Fig. 3, or to the left if crank 21 is engaged in slot 12. As shown, the device can only control two ratios, but in practice two or three parallel selector rods 1. and latch levers 5, &c., are provided. In one modification, Fig. 6, not shown, the latch lever is spring-loaded to preselect the desired ratio by a rotatable cam and the pin 16, and slot 15 are replaced by two fixed pins engaging suitably shaped surfaces on the upper and lower sides of the lever, and in another modification, Fig. 7. also not shown, the latch lever is moved linearly by engagement with one or other parts of a double rack driven by a single pinion. A lock may be provided to prevent full engagement of the clutch before the selected gear has been engaged.