Patent ID: 7497309

Claim:
A bicycle brake lever for being used on a handlebar of a bicycle and having a body adapted for being mounted with the handlebar of the bicycle and having a threaded hole defined in the body; a connecting collar formed on the body and used to mount rotatably around the handlebar of the bicycle; and a lever mounted pivotally with the body near the threaded hole and having a shaft extending into the threaded hole; a hydraulic cylinder mounted on the body and having a proximal end; a distal end; an external surface; an outer thread formed around the external surface near the proximal end of the hydraulic cylinder and screwed with the threaded hole of the body; an oil chamber formed inside the hydraulic cylinder; a piston mounted moveably in the oil chamber and having a front end connected with the shaft of the lever; and a rear end; and an annular groove formed around the external surface between the proximal end and the distal end of the hydraulic cylinder and having two transmitting holes formed longitudinally through a bottom of the annular groove and communicating with the oil chamber; an oil jacket mounted rotatably around the hydraulic cylinder over the annular groove, contacting with the body near the threaded hole and having a rear open end; a front open end contacting with the body and over the threaded hole; and a tube formed radially on the oil jacket at a position corresponding to the annular groove and having an opening; a cap mounted over the opening of the tube; and a leakage proof element mounted between the opening of the tube and the cap to prevent the oil leaking from the oil jacket.