TRANSMISSION

摘要

1418764 Change-speed control TOYOTA JIDOSHA KOGYO KK 23 Jan 1973 [24 Jan 1972] 3492/73 Heading F2D In a transmission having a first fork shaft for engaging forward ratios and a second fork shaft for engaging a further forward ratio and reverse, a selector engageable with recesses in the fork shafts has biasing means defining non-aligned first and second travel paths through which it is moved for actuating the second fork shaft, and restricting means are provided whereby when the selector is positioned in the first travel path it can be moved only between positions establishing the forward ratio and neutral, reverse being selectable only after further transverse movement of the selector against the biasing means to the second travel path. In one embodiment a selector lever 2, held in a spherical socket 4 by a spring 7, is selectively engageable with recesses 12, 13, 14 in the ends of fork shafts 9, 10, 11 which have interlocking means 15, 16. First and second ratios are established by the shaft 9, third and fourth by the shaft 10, and fifth and reverse by the shaft 11. The lever coacts with a plate 21 supported at one end by a set-bolt 22 and slidable at the other end on a shaft 23 so that when the lever is moved towards the recess 14 it encounters resistance as a spring-loaded ball 28 rides up a ramp 251a. When a further ramp 2511a engages the ball the lever is positioned so that it engages portions 13b, 14b of the recesses 13, 14 and cannot therefore move the shaft 11 to the left to establish reverse ratio but is enabled to move the shaft 11 to the right to establish fifth ratio by engagement with a portion 14a of the recess 14. Reverse is engageable only after further movement of the lever 2 to overcome the additional resistance provided by the ramp 2511a. A modification has a spring-loaded plunger in the recess 14 instead of the plate 21 and ball 28. In a further modification the fork shafts are operated by an arm on the end of an intermediate shaft the other end of which is connected to the selector lever and spring-biased to the third and fourth ratio position, and a spring-loaded plunger in the recess of the fifth and reverse fork shaft, or in the casing, coacts with a cam on the arm to provide the resistance to reverse ratio selection. When the plunger is in the casing it may operate a reversing light switch.