| 摘要 |
646,094. Facilitating speed-change. WEBSTER & BENNETT, Ltd., and BENNETT, D. W. April 26, 1948, No. 11365. [Class 80(ii)] A pneumatic, hydraulic or electric inching device, for imparting a slow oscillatory movement to the main input shaft c of a sliding - gear or clutch change-speed gear during a manual or power shift. whilst the main clutch is disengaged, to facilitate gear engagement, is controlled by the sliding gear members b, Fig. 3, so that the device functions only when one or more are not in correct mesh. In the hydraulic control shown the input shaft c is slowly oscillated by a reciprocating piston o, Fig. 4, having rack-and-pinion engagement m, with a disc h which is frictionally or positively clutched to the input shaft c by pressure applied to the right face of a piston g, Fig. 3, in opposition to pressure acting constantly on its stepped left face. Movement of any one or more of the sliding-gears b, Fig. 3, from its engaged position closes a corresponding one of a group of valves t arranged in series in a pipe-line w, thus cutting off pressure-supply from an inletx through the line w to the lower face of a piston-valve 5, Fig. 2 which then moves downwards u n d e r load of a spring or, as shown, of pressure act in g constantly through an inlet 7 or the upper face of a push-piece 26 of lesser diameter. This downward valve movement cuts off a pressure inlet 8 and exhausts at 32 the line 9 of the main hydraulically-actuated clutch (not shown), which then disengages. At the same time the valve 5 shuts off an exhaust-port 27 from, and pressurizes, from the inlet 7 through a passage 28, a line 11 leading to the right face of the inching-clutch piston g, Fig. 3, which then engages. Movement of the valve 5, Fig. 2, also opens the pressure-inlet passage 28 to a passage 29 opening to a reversing-valve 6, which initially feeds pressure through a line 17 to the left inlet r, Fig. 4, of the inching-piston o, which then makes a stroke to the right, inching the input shaft c, at the completion of which it operates a change-over valve 22 which changes the feed-connection of a pressure-inlet 23 from a line 19 leading to the upper face of the reversing-valve 6, Fig. 2, to a line 20 leading to its lower face, whereby the reversing-valve 6 moves up to exhaust the line 19 and pressurize the line 20 leading to the right inlet s of the inching-piston o. The latter then makes a return stroke to the left, operating the change-over valve 22, to continue the reciprocating sequence until completion of mesh of the desired gear causes the valves t again to open the pressure-line w, which returns to the piston-valve 5, Fig. 2, to its upper portion exhausting the inching- piston and inching-clutch lines 29, 11, and again feeding the main-clutch line 9 to resume drive in the new ratio. According to the Provisional Specification the rackpiston o may turn the shaft through a oneway clutch to impart stepwise angular movement thereto in one direction only.
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