Velo Research, Inc.

Buford H Hopper

Jeffrey C Brown

Mauricio Mirand

Robert Brown

Harry G Worth

An air pump for use with a chain-driven bicycle having a free wheel. The pump assembly comprises a pair of opposed cylinders and a double-ended piston rod mounted in a housing. The piston rod has a bearing slot, which engages a crank pin on a crankshaft driven by a sprocket. Rotation of the sprocket reciprocates the double-ended piston rod in the cylinders. The cylinders are each integrally formed with a manifold that uses an elastomeric band covering a passage from the cylinder interior to inside the manifold as a one-way valve. An enlarged diameter skirt on each cylinder allows air to enter the cylinder on each intake stroke. A cap defining the piston head is locked onto each piston and holds a seal in place on the piston. An integral clamp assembly allows the pump to be removably mounted on a bicycle chain stay. The lower run of the bicycle drive chain engages the drive sprocket of the pump assembly, and a chain retainer is used to maintain the engagement of the drive chain with the drive sprocket. Reverse rotation of the bicycle's crank assembly causes the conventional free wheel to also rotate in a reverse direction without rotating the wheel of the bicycle. The resulting movement of the chain over the drive sprocket of the pump rotates the drive sprocket, which reciprocates the double-ended piston rod in the cylinders, and pumps air to an article to be inflated, such as the bicycle tire(s).

Piston assembly for use with a bicycle operated air pump

Bicycle operated air pump

An air pump for use with a chain-driven bicycle having a freewheel. The pump assembly comprises a pair of opposed cylinders and a double-ended piston rod mounted in a housing. The piston rod has a bearing slot which engages a crank pin on a crankshaft which is driven by a sprocket. Rotation of the sprocket reciprocates the double-ended piston rod in the cylinders. A hook-shaped extension of the housing fits over the top of the chain stay of the bicycle, and a vertically movable clamping member provided with a ratchet mechanism abuts the underside of the chain stay; a lever operated cam clamps the chain stay intermediate the hook portion and the clamping member. The lower run of the bicycle drive chain engages the drive sprocket of the pump assembly. Reverse rotation of the bicycle's crank assembly causes the conventional freewheel to also rotate in a reverse direction without rotating the wheel of the bicycle. The resulting movement of the chain over the drive sprocket of the pump rotates the drive sprocket, which reciprocates the double-ended piston rod in the cylinders and pumps air to an article to be inflated.

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Bothell, WA, United States of America

Buford H Hopper