US 5,672,133 AGranted

Bicycle gearing system

OwnerTom Edeninventor

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Abstract

In combination, a bicycle having a frame and front and rear wheels and a bicycle gearing system which includes a movable bottom bracket mounted on the frame of the bicycle. A pedal axle is rotatably mounted in the bottom bracket. A chain extends between the front gear sprocket and a selected one of the rear gear sprockets. A rear derailleur is mounted on the frame generally adjacent and forward of the rear gear sprockets, the rear derailleur operative to engage the chain and shift the chain transversely relative to the frame. The chain is of a size and shape such that when the bottom bracket is in a forward position, the chain is tensioned, and when the bottom bracket is in the rearward position, the chain is detensioned. The chain is detensioned and the rear derailleur shifts the chain transversely relative to the frame such that the chain engages a different selected one of the rear gear sprockets. The movable bottom bracket is then returned to the forward position thereby retensioning the chain and retaining the chain on the different selected one of the rear gear sprockets.

Claims11

Dependent claims

In combination:

a wheeled vehicle having a frame and front and rear wheels rotatably mounted thereon;
and
a gearing system comprising:
a movable bottom bracket movably mounted on said frame of said wheeled vehicle, said bottom bracket movable between at least one forward position and at least one rearward position, said bottom bracket free of securement means operative to immovably fix said bottom bracket in one position;
a pedal axle rotatably mounted in said bottom bracket and extending transversely to said frame;
crank means mounted on said pedal axle for rotating said axle;
at least one front circular gear sprocket mounted on, generally perpendicular to and concentric with said pedal axle;
at least two rear circular gear sprockets each having a different diameter, each mounted concentrically with one another adjacent said rear wheel on one of said rear wheels and said frame generally parallel with said front gear sprocket, said rear gear sprockets operatively connected to said rear wheel for transference of rotational force thereto;
chain means extending between said front gear sprocket and a selected one of said rear gear sprockets for transferring rotational force applied to said crank means and said front gear sprocket to said selected one of said rear gear sprockets thereby rotating said rear wheel;
a rear derailleur means mounted on said frame generally adjacent to and forward of said rear gear sprockets, said rear derailleur means operative to engage said chain means and shift said chain means transversely relative to said frame such that said chain means is moved to engage a different rear gear sprocket thereby shifting gears;
said chain means being of a size such that when said bottom bracket is in said forward position, said chain means is tensioned thereby retaining said chain means on said front gear sprocket and a selected one of said rear gear sprockets, and when said bottom bracket is in said rearward position, said chain means is detensioned;
and
said gearing system operative to shift gears upon said movable bottom bracket being moved to one of said rearward positions thereby detensioning said chain means, said rear derailleur means operative to shift said chain means transversely relative to said frame such that said chain means engages a different selected one of said rear gear sprockets, said movable bottom bracket being moved forwardly thereby retensioning said chain means and retaining said chain means on said different selected one of said rear sprockets.

10 more elements

A method for shifting gears on a wheeled vehicle comprising the steps:

providing a wheeled vehicle having a frame and front and rear wheels rotatably mounted thereon having a gearing system including a movable bottom bracket movably mounted on said frame of said wheeled vehicle, said bottom bracket movable between at least one forward position and at least one rearward position and a pedal axle rotatably mounted in said bottom bracket and extending transversely to said frame;
providing crank means mounted on said pedal axle for rotating said axle, at least one front circular gear sprocket mounted on, generally perpendicular to and concentric with said pedal axle and at least two rear circular gear sprockets each having a different diameter, each mounted concentrically with one another adjacent said rear wheel on one of said rear wheel and said frame generally parallel with said front gear sprocket, said rear gear sprockets operatively connected to said rear wheel for transference of rotational force thereto;
providing chain means extending between said front gear sprocket and a selected one of said rear gear sprockets, a rear derailleur means mounted on said frame generally adjacent to and forward of said rear gear sprockets, said rear derailleur means operative to engage said chain means and shift said chain means transversely relative to said frame such that said chain means is moved to engage a different rear gear sprocket thereby shifting gears, said chain means being of a size such that when said bottom bracket is in said forward position, said chain means is tensioned thereby retaining said chain means on said front gear sprocket and a selected one of said rear gear sprockets, and when said bottom bracket is in said rearward position, said chain means is detensioned;
moving said bottom bracket towards said rearward position thereby decreasing the distance between said front gear sprocket and said rear gear sprockets and detensioning said chain means;
engaging and moving said rear derailleur means transversely relative to said frame to align said rear derailleur means with a newly selected one of said rear gear sprockets;
rotating said pedal axle and said front gear sprocket whereby said chain means is rotated about said front gear sprocket and said newly selected one of said rear gear sprockets, said chain means being seated on said newly selected one of said rear gear sprockets by said rear derailleur means being aligned with said newly selected one of said rear gear sprockets;
and
moving said bottom bracket towards said forward position thereby retensioning said chain means and seating said chain means on said newly selected one of said rear gear sprockets.

5 more elements

Dependencies are inferred from the claim text.