| 摘要 |
<p>A covered bicycle transmission is proposed which is simple in structure and can be mounted on various types of existing bicycles. The bicycle transmission includes a rotary member 1 fitted around a main shaft 51, as many main gears 2, 3, 4 and 5 as the number of reduction steps which are arranged in a row around the rotary member 1, a plurality of counter gears 7, 8, 9 and 10 rotationally fixed to a countershaft 6 extending parallel to the main shaft 51, the counter gears being linked to the respective main gears and rotated at predetermined speeds corresponding to the respective main gears, ratchet pawls 15, 16, 17 and 18 carried on the rotary member 1 so as to correspond to the respective main gears, the main gears having ratchet teeth 19 on their inner peripheries with which the respective ratchet pawls are configured to be brought into meshing engagement, and a switch member 20 for selectively protruding and retracting the respective ratchet pawls from and into an outer periphery of the rotary member 1, wherein by operating the switch member, the ratchet pawls 15, 16, 17 and 18 are individually and selectively brought into and out of engagement with the corresponding ratchet teeth 19, whereby driving force is selectively transmitted through one of the main gears 2, 3, 4 and 5 and one of the counter gears 7, 8, 9 and 10 corresponding to the one of the main gears, thereby changing the rotational speed ratio between input and output members.</p> |
