Self locking bearing preload adjuster
A bearing preload adjuster for a bicycle crank set and bottom bracket comprises an adjustment ring for coupling with a bicycle crank arm, a movable plunger comprising an external thread for rotatably coupling with the adjustment ring. The adjustment ring is rotated in order to cause the plunger to extend along an axis of the bottom bracket and apply pressure to a bottom bracket bearing inner race. The adjustment ring is rotated until the clearance in the bearing assemblies and the play in the bottom bracket assembly has been eliminated. This allows the crank assembly to rotate freely, while preventing the crank assembly from sliding side to side inside the bearing bores and along the axis of the crank spindle.
1. A bearing preload adjuster for a bicycle crank set and bottom bracket comprising:
a. an adjustment ring for coupling with a bicycle crank arm;
b. a movable plunger comprising an external thread that rotatably couples with an internal thread of the adjustment ring such that when the adjustment ring is rotated a threaded interface between the adjustment ring and the movable plunger extends the movable plunger relative to the bottom bracket to apply preload to one or more bearings of the bottom bracket;
c. a detent spring, wherein the preload adjuster is slid over an adjuster boss of the bicycle crank arm to couple the preload adjuster with the bicycle crank set and bottom bracket; and
d. a spindle;
e. a gasket adapted to prevent water and dirt from contacting the one or more bearings of the bottom bracket;
f. each of the movable plunger, detent spring and gasket includes a respective at least one anti-rotation feature that engages in an at least one anti-rotation feature of the adjuster boss;
g. the detent spring includes a spring detent feature that engages within one of a plurality of adjustment ring detent features.
2. The bearing preload adjuster of claim 1 wherein the bicycle crank arm comprises a non-drive side bicycle crank arm.
3. The bearing preload adjuster of claim 2 wherein the adjustment ring is rotatable in a counter-clockwise direction as viewed from an outside edge of the non-drive side bicycle crank arm to move the plunger and apply preload to the one or more bearings of the bottom bracket.
4. The bearing preload adjuster of claim 1 wherein the detent spring prevents the movable plunger from backing out once the movable plunger has been moved in order to apply preload to the one or more bearings of the bottom bracket.
5. The bearing preload adjuster of claim 1 wherein the bearing preload adjuster comprises a triple-start thread which is used to apply preload to the one or more bearings of the bottom bracket.