| 摘要 |
A shiftable pedal bearing for a bicycle or the like includes a pedal bearing housing supporting a hollow crank axle carrying pedal cranks, and a gear casing with pertaining chainwheel and accommodating a disk which extends parallel to the chainwheel. Arranged in the crank axle is a switch shaft which is actuatable from outside by a shifter so that a coupler, which is operatively connected to the switch shaft, is selectively engageable with circumferential recesses in the chainwheel and a disk. Each recess of the chainwheel and each recess of the disk is of stepped configuration to define a first recess section and a second recess section, with the coupler in a first stage engaging the first recess section with play and in a second stage snugly fitting in the second recess section with no play.
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