GB191512398A - Improvements in or relating to Driving Mechanism for Bicycles or the like Velocipedes. - Google Patents

Abstract

12,398. Keefe, J. Aug. 28. Variable-speed toothed gearing.-In order that the reach of a bicycle &c. may be varied without altering the position of the saddle, the crank-shaft f is mounted in a journal block e which is adjustably mounted in the curved slot or guideway b of a bracket a, the sides of the slot being arcs of circles with the back wheel axle c as centre. The drive may be transmitted through a countershaft gear of variable velocity ratio, the countershaft u also being mounted in the curved slot. The gear is controlled by wires y, l<1> connected respectively to the journal block of the countershaft and to a sliding clutch p upon the crank-shaft. This clutch turns with the wheel o, but can slide relatively to it. In its inner position, the clutch engages teeth r upon a gear-wheel n and so locks this wheel to the sprocket-wheel ; in its outer position, the clutch engages a key on the crank-shaft and thus connects the sprocket-wheel to the shaft. The wires are connected to a lever z in such manner that movement of the lever in one or the other direction exerts a pull in one wire and relieves the tension in the other. Thus, when the wire v is pulled, the countershaft is raised, and, the tension in the other wire l<1> being relieved, the clutch is pressed to its outer position by a spring s. The block e is adjusted by a screw j engaging an extension i, or the block may carry a screw which is engaged by a nut rotatably mounted in the bracket. The upper block rests upon a stud or distance-piece adjustably carried by the block e.