Patent ID: 8464845

Claim:
A master cylinder for a bicycle hydraulic disc brake comprising: a master cylinder housing; a lever handle pivotally connected to the master cylinder housing; a bar clamp attached to the master cylinder housing for attaching the master cylinder housing to a bicycle handlebar along a clamp axis; a cylinder wall associated with the master cylinder housing, the cylinder wall comprising a cylinder interior and a cylinder exterior extending axially of a cylinder axis, the cylinder having a first end and a second end and the cylinder axis being non-parallel to the clamp axis; a reservoir for hydraulic fluid associated with the master cylinder housing, the reservoir comprising a first wall comprising only a limited radial portion of the cylinder exterior and an elastomeric diaphragm, wherein the cylinder axis and the clamp axis lie in a plane intersecting the first wall, the cylinder axis being substantially perpendicular to the clamp axis and wherein the reservoir is disposed substantially entirely between the clamp axis and the lever handle; a port in the first wall between the first and second cylinder ends providing fluid communication between the reservoir and the cylinder interior, the first wall facing a direction the lever handle extends away from the master cylinder housing; and a piston within the cylinder having a seal operatively associated therewith, the piston being moveable along the cylinder axis between the first and second cylinder ends, the seal preventing flow of hydraulic fluid from the reservoir to the second cylinder end upon the seal advancing axially past the port as the piston moves from the first toward the second cylinder end, the master cylinder housing and the reservoir being configured such that the master cylinder may be operatively disposed on either a right or left portion of a handlebar of a bicycle without effecting operation of the master cylinder by a user.