Patent GB-319528-A (GB)
Title: Improvements in and relating to change speed gears
IPC: F16H29/08
Filed: 1928-10-27
Abstract: 319,528. Lange, A. Oct. 27, 1928. Addition to 279,772. Variable-speed gearing according to the parent Specification comprises a rotary driving cam 3, Fig. 3, constructed so as to impart uniform motion to a one-way driven wheel 52 by working back to the cam from the uniform motion of the wheel. Power passes by way of a lever 5, a link 7, a variable lever 8, and a link 9 to the one-way drive. The speed is varied by displacing the fulcrum block 11 of the lever. The one-way drive comprises a set of spring plungers 46, one of which is always in position to .drive, but which do not drive reversely. The present invention provides means within the ingearing for reversed driving in two forms, a first form in which the fulcrum 11 is moved bevond the link 9, and a second in which the one-way drive is reversible. An example of the first form is shown in Fig. 3. The link 9 is jointed to an arm 48 upon a drive ring 50 which carries the plungers 46, which are freed or withdrawn by the relative turning of a control cam, ring 42 operated from a slotted expansible guide 36. A spring pin 39 moving in the guide 36 rocks a lever 38 which controls the plunger 46. To move the fulcrum block 11 and so change the speed, a lever 17 is moved by hand or by a governor. The Lever 17 is connected through gearing 26 and a shaft 28 to a screw, 55 which makes appropriate adjustment of the guide 36. When the block 11 i.; moved beyond link 9 for reversed driving, the gearing 26 reverses also and again the appropriate change is made in the guide 36 to suit the reversed action of the pungers. The plungers 46 are shaped so as to spring out of engagement with driven wheel 52 on overload. An example of the second form with reversible positive plunger one-way drive is shown in Figs. 11 and 13. In this form the fulcrum 11 does not move beyond the link 9, which oscillates through arm 10, a drive rung 16 carrying spring plungers 30 one of which is in position to engage multiple recesses in the driven wheel 52. The one-way drive is effected by raising the plungers 30 out of engagement at the end of the stroke by lateral pins 31 on the plungers riding up on cams 35 on a control ring 27. There is a second control ring 26 with cams 36 projecting into an outer runway 38 of the pins 31. The control rings 26, 27 are connected by links 40, 41 to a control cam 45 operated from the same lever 51 which through rack gear 61 moves the fulcrum block 11 to change the speed. The control rings 26, 27 can be relatively adjusted so as to keep the plungers 30 out of action to disconnect the drive, or to operate them so as to reverse the drive. An example of the first form with a frictional one-way drive is shown in Fig. 15, reversal being effected by moving fulcrum 11 beyond link 9. The oscillator 15 is connected at 75 to an expansible segment 16, but external bands or toggle-controlled shoes might be used. Attached to the driving cam 3 is control cam 71 which pushes a rod 94, so that during the proper part of the oscillation of clutch 16, a wedge 72 is thrust between its ends so as to make it grip and drive driven wheel 52. The rod 94 is interrupted by a sliding differential screw 86, so that by moving a lever 88 the wedge 72 is withdrawn, and the drive disconnected. An example of the second form with reversible friction drive is obtained from the arrangement shown in Fig. 15 by providing two control cams such as 71 in opposite phase, which are operative alternatively for forward and reversed driving. Each control cam has its own grip segment 16, and either one-way drive is rendered operative by the actuation of its appropriate differential screw lever 88. An arrangement similar to that of Fig. 15 is described in which the engine piston drives direct to the lever 8 and the cam 8 no longer drives but regulates the drive to get uniform turning of the driven element.