A coast brake of the type having a screw cone provided with a tapered part to be screwed into an internal end part of a male screw cylinder to which a chain gear is fixed, the screw cone being removed by means of the rotation of the male screw cylinder. A brake shoe is in mesh with a fixed brake cone which is provided outwardly of the screw cone to engage with a hub body by pressing the brake shoe being expanded. The coaster brake further includes: a cylindrical part smaller in diameter than a top end part of the brake cone being provided on one end part of the brake cone; a clutch spring with a projection being fitted on an outer periphery of the cylindrical part to exert a force in a direction of fastening itself when a negative rotational force works upon the projection around the cylindrical part; and an axial notch part provided on the screw cone, the projection of the clutch spring being in mesh with this notch part.
The coaster brake of this invention is provided with a clutch cone screw-fitted to a driving body which is driven by pedals, to be axially movable in correspondence with the driving body's turning direction, a brake cone supported through a clutch mechanism which is not turnable in the forward direction, but which allows its turning in the reverse direction, and a brake members which is operated to apply brake on the hub shell by the aforementioned clutch cone moving to approach the aforementioned brake cone side, when the driving body is turned in a reverse direction. When the hub shell is turning in the forward direction, the brake action may be exhibited by applying to the driving body reverse rotation similarly top conventional coaster brake. Besides, the aforementioned brake cone is rotatable in the reverse direction by means of the clutch mechanism and as the driving body is subjected to a reverse turning, when the hub shell is not turning in the forward direction, the aforementioned brake cone will turn in the reverse direction integrally together with the driving body, the clutch cone and the brake member and in concert with the hub shell; thus, the coaster brake mechanism operates as a reverse driving mechanism.
A braking mechanism for actuating a supplemental brake, used in association with a pedal-actuated brake, which increases total brake effectiveness and increases reliability through redundancy as a result of the coaster brake functioning as a back-up to a failed supplemental brake. A brake lever arm is adapted to cooperate with a coaster brake and a bicycle frame to engage a brake cable and operate the supplemental brake when the coaster brake is engaged. During assembly, the brake lever arm is allowed to rotate about an axle, but is limited in such rotation to a selected degree by placement of a limiter cam. Once installed, a distal end of the brake lever arm is permitted limited rotation with respect to the bicycle. A brake cable secured between the brake lever arm distal end and a supplemental brake is disposed linearly a distance sufficient to actuate the supplemental brake.
