Patent GB-451109-A (GB)
Title: Improvements in preselecting mechanism for gear boxes of self-propelled vehicles
IPC: F16H63/46
Filed: 1935-01-25
Abstract: 451,109. Change-speed gearing. HUMPHREYS, C. H., The Grange, Carlton, Bedford. Jan. 25, 1935, Nos. 2568 and 4195. [Class 80 (ii)] Preselective gear-changing mechanism comprises selector-rods 1 .. 4, each of which is moved to a position for engaging a corresponding sliding gear or clutch element by a pivoted finger 25 .. 28, acting directly on the selector-rods under the influence of spring-pressure 9.. 12, controlled by a cam-selector 18, adapted, at any period of operation of the main-clutch pedal or at any other time to bias a selected finger 25 .. 28 for engagement with its selector-rod, the clutch pedal being connected through a lost motion linkage 15, 16, 64, Fig. 2, to a transverse bar 13, which, during downward movement of the pedal is moved bodily from left to right of Fig. 1, to return all the selectorrods to neutral. The selector-rods are provided with interlocking means described below. In Figs. 1 to 13 the four selector-rods 1 .. 4 all move from right to left of Fig. 1 for gear engagement, although one of them, or an additional one, may move oppositely. The gear-engaging springs 9 .. 12 connect the fingers 25 .. 28 with corresponding levers 27a, on the opposite side of the cam-drum 18, turning of which latter lifts a selected lever 27a, &c. and removes the inward restraint from the corresponding finger 25 &c. The effect of this is merely to tension the corresponding spring 9 &c. and apply a gearengaging leftward bias to the corresponding selector-rod, which latter, by virtue of the interlock is not free to move until the clutchpedal has returned any previously engaged gear to neutral, whereupon the spring engages the new gear during the return movement of the pedal. The fingers 25 &c. and levers 27a &c. operatively engage the cam-drum 18 through lugs 32, and there is normally a slight clearance between the fingers and the sleeves 1a .. 4a through which latter they operate the selector-rods. The interlocking arrangement comprises three mutually abutting pivoted fingers 7c, d, e, Figs. 9 and 13, engaging the reduced ends 1c ... 4c of the selectorrods, to permit only one of the latter to move at a time. Spring-loaded ball-detents 8, Fig. 1, hold the rods in gear and also, if desired, neutral positions. To set the gear in neutral, the preselector camshaft is set between any two gear-positions, thereby tending to engage two gears at once, whereupon the interlock precludes any gear engagement. Alternatively a separate cam-plate may be provided for this purpose. In the modification shown in Fig. 14, each selector-rod 71 is operated by a pivoted strut 79, which, under the influence of a spring 83 and yoke 81, tends to set itself in a propping position in a notch 74 in the selector-rod, such tendency being resisted by a blade-spring 80 and a common preselector camshaft 84, which depresses the yoke 81 and allows the strut 79 to fall to an inoperative position below the notch 74. The struts are pivoted on arms 75, carried by a common shaft 76, connected by linkage to the clutchpedal, and acted on by a spring 78 which moves all the struts in the gear-engaging direction, i.e. left to right of Fig. 14. Alternatively the struts may be pivoted to the selector-rods. The arms 75 engage parts 72 of the selector-rods to neutralize them when the clutch-pedal is depressed. Neutral may be obtained by a dummy rod 71 and associated parts. To facilitate change, a normallylocked free-wheel tail-clutch 45a, Fig. 3, is unlocked at 46 by a rod 53 operated by the clutch-pedal, which rod also resiliently oporates brake-cones 47, 49, which frictionally arrest both the input and the output shaft of the gear. The free-wheel clutch is provided with means for preventing asynchronous locking, as described in Specification 435,278. The constant-mesh three-speeds-and-reverse gear shown in Fig. 3, comprises a sliding second-speed pinion 43f, adapted to be clutched to a primary driving-pinion 41 for directdrive ; a pinion 42b loose on the countershaft and slid into clutching engagement therewith at 42d for second speed, and a loose pinion 43c clutched to the driven shaft 43 at 43e for low-speed. Reverse is effected by sliding a normally stationary compound idler 44a, 44b into mesh respectively with a fast countershaft-pinion 42a and a toothed-ring 44c, carried by the driven member 45 of the tail-clutch 45a. The main-clutch pedal may be actuated automatically by decelerating the engine. Specifications 402,924 and 406,500 also are referred to.