Patent GB-406500-A (GB)
Title: Improvements in mechanism for selecting and operating any desired one of a pluralityof rods or the like
IPC: F16H63/46
Filed: 1933-04-12
Abstract: 406,500. Controlling change-speed gearing. HUMPHREYS, C. H., The Grange, Carlton, Bedford. April 12, 1933, No. 10969. [Classes 80 (ii) and 80 (iii).] In preselective control mechanism for operating one of a number of normally-locked slidable members, such as the selector bars of changespeed gearing upon a vehicle, the selective control acts to change a positive lock to a friction-held lock, the latter being afterwards released by a simple movement of a control common to the slidable members, such as the clutch pedal. Thus, in Fig. 5, 21 is one of a number of slidable bars biassed to the right by main springs, not shown, and locked by the engagement of each by a pawl 49. The selector is a disc 13 carrying cams 14. The preselection turns the disc 13 so as to bring a cam 14 between two feelers 15 so as to turn one feeler to the position shown in Fig. 6. A spring 46 between the feelers is thus stressed producing thrust on a pin 47 tending to lift the pawl 49 out of locking engagement. The pawl 49 is held in locking engagement by friction on its end caused by the rightward pull in the bar 21. Depression of the clutch pedal throws a disc block 54 to the left. This, by striking a lug 55 on any bar previously in a gear position, returns such bar to locked neutral position and by a blow on the lug 55 of the bar now selected shakes the pawl 49 clear so that the pawl is lifted. On release of the clutch pedal, the selected bar 21 then follows the block 54 to the right into a gear position. In a form of gear control shown also in Figs. 1, 2, 3 and 4, there are five bars 16, 18, 20, 21, 22 which like the bar 21 of Fig. 5 are adapted to be moved to the right of Fig. 2 when preselected by the turning of a single disc 13 and released by depressing the pedal 1, Fig. 1, so throwing the block 54 forwardly. The disc 13 is turned by a connector 12, Fig. 1, from a suitable preselector lever. The two lower bars 21, 22, Fig. 3, are connected by mediallypivoted levers 23, 24 to other bars 17 and 19 so that of five bars 16, 17, 18, 19 and 20, Fig. 2, in one plane alternate ones are moved in opposite directions by the main springs on release of the clutch pedal. A main spring 30 operates the bar 16 alone for reversed driving. A double-acting main spring 33 operates the three bars 17, 18 and 22 and a similar spring 36 operates the three bars 19, 20 and 21. A reverse fork 27A is carried directly on a boss 27 fast on the bar 16. A fork 42 for first and second speeds is carried on a saddle 38 slidable on both bars 17, 18. A fork 43 for third and fourth speeds is carried on a saddle 39 slidable on both bars 19, 20. To engage first speed, the disc 13 is turned to bias the locking pawl 49, Fig. 6, of the bar 22, Fig. 3. On depressing the pedal 1, Fig. 1, the block 54 frees the bar 22 so that the bar 17 slides left of Fig. 2. A boss 25 or the bar 17 strikes the saddle 38 so as to bring the fork 42 to first-speed gear position 42A. To engage second speed, the disc 13 is turned to select the bar 18 and the pedal actuated. As the bar 17 returns to neutral, a pin 60 on it carries the saddle 38 with it as far as neutral, and, on release of the pedal, a boss 28 on the bar 18 strikes the saddle 38 and carries it farther to bring the fork 42 to secondspeed gear position 42B. The fork 43 is similarly moved to third and fourth speed gear positions 43A, 43B. The five bars 16, 17, 18, 19, 20 are interlocked by lock lovers 70, Figs. 2 and 3, so that one only can be moved at a time. How this acts is readily seen from Fig. 19 which shows three bars 202 interlocked by two levers 207 with arms 208 adapted to touch each other. Each lever 207 interlocks its two adjacent bars, and the pair of levers contacting at 208 interlock the two outer bars. The T- shaped levers 70, Figs. 2 and 3, hang from pivots 69 between tapered or constricted parts of the five bars. There is only sufficient room for the arms of the T's to separate far enough at one place to allow one bar only to move its larger part between the lever stems. Other complete gear control arrangements are described having three bars, like Fig. 19, adapted to be moved in opposite directions. Such arrangements have a selector cam disc at each end of the gear box and a lever is provided so that actuation of the clutch pedal throws different parts simultaneously in opposite directions.