Bicycle crank arm
OwnerFrank Hermansen, Carl Winefordnerinventors
Life of this patent
Estimating the term…
Abstract
A hollow bicycle crank arm has a central tubular portion to reduce weight and two mounting-boss portions for mounting a crank spindle and pedal during use. A crank arm base is forged or cast with a relatively thin back and sides, preferably out of aluminum or magnesium. The crank arm base has a generally C-shaped cross section. An arm cover has a top and sides and is made from stamped steel or titanium. The cover is placed over the open crank arm base to enclose a significant hollow section. The stamped arm cover does not require any threading or welding. It can be made using a very inexpensive stamping process. The crank arm can be made using relatively inexpensive traditional manufacturing processes such as die casting or forging.
Claims13
A bicycle crank arm comprising:
- an arm base having a hollow recess;
- and
- an arm cover secured to said base over said recess to form a hollow crank arm.
A bicycle crank arm comprising:
- an arm base;
- and
- an arm cover;
- the base and cover being made of different materials.
A bicycle crank arm comprising:
- an arm base;
- and
- an arm cover;
- the base and cover being made by respectively different processes.
A bicycle crank arm comprising:
- an arm base;
- and
- an arm cover;
- said base and cover being affixed to one another by a pedal thread insert.
A bicycle crank arm comprising:
- an elongated arm member having a first end for connection to a pedal and a second end for connection to a bottom bracket;
- and
- a pedal thread insert insertable into said first end of said arm member and selectably removable therefrom for replacement thereof.
Dependencies are inferred from the claim text.