BICYCLE BOTTOM BRACKET Russian patent published in 2005 - IPC

FIELD: transport engineering; bicycles; foot crank mechanisms.

SUBSTANCE: left-hand crank 3 is provided with square hole for mounting on shaft 1 and cylindrical groove with thread mating with hollow bolt 2 freely fitted on shaft 1. Said bolt thrusts through its left-hand end face surface against support bead of shaft. With left-hand crank 3 tightened by hollow bolt 2, shaft 1 is fitted in bearing unit, and left-hand bearing 8 prevents turning out of hollow bolt 2. Thread is made on outer surface of shaft 1 from right-hand side of shaft on which union nut 4 is installed to support right-hand bearing 9. Body of nut is made in form of cylindrical bushing of which driving sprockets 5 are mounted for free rotation. Bead of union nut 4 limits axial displacement of sprockets 5. Groove with thread is made in sprocket hub 6, and thread is made on outer surface of hub of right-hand crank 7 to provide possibility of tightening of right-hand crank 7 provided with square hole for mounting on shaft 1 by freely rotating hub 6 of sprockets which plays the part of nut.

EFFECT: prevention of spontaneous turning out of bottom bracket parts, provision of sealing of bottom bracket.

5 cl, 2 dwg