Reach adjustment mechanism for a master cylinder lever of a hydraulic disc brake

A master cylinder for a hydraulic disc brake comprising:

• a housing defining a cylinder, the cylinder having a first and second end along its axis;
• a piston received in the cylinder, the piston having a radial seal between the piston and cylinder;
• a lever pivotably associated with the housing for pivoting between a rest position and an actuated position relative to the housing;
• a push rod operatively associated with the piston and the lever to move the piston axially within the cylinder as the lever is actuated between the rest and actuated position;
• a threaded engagement between a first end of the push rod and the lever, the threaded engagement being configured to cause movement of the rest position of the lever relative to the housing when a rotating force is applied to the push rod causing axial rotation of the push rod;
• and
• indexing means operatively associated with the push rod for providing indexed axial rotation of the push rod upon application of the rotating force to the push rod causing axial rotation of the push rod.

A master cylinder for a bicycle hydraulic disc brake, the master cylinder comprising:

• a housing defining a cylinder, the cylinder having a first and second end;
• a hydraulic reservoir;
• a port between the hydraulic fluid reservoir and the cylinder providing fluid communication between the hydraulic fluid reservoir and the cylinder, the port having a port opening located between the first and second ends of the cylinder;
• a piston received in the cylinder having a radial seal, the piston being movable between a select starting position with the seal between the first end and the port opening with the seal a select distance from the port opening and a pressurized position with the seal between the port opening and the second end, the radial seal preventing fluid flow between the cylinder and the reservoir when positioned between the port opening and the second end to pressurize the second end;
• a lever pivotably attached to the housing, the lever being operatively associated with the piston to move the piston between the select starting position and the pressurized position as the lever is pivoted between a rest position and a fully actuated position;
• dead band adjustment means operatively associated with the piston for moving the radial seal to adjust the select distance between the port opening and the seal;
• and
• compensating means operatively associated with the dead band adjustment means and the lever to maintain the lever in a select rest position as the dead band adjustment means is actuated to adjust the select distance between the port opening and the seal.

A master cylinder for a bicycle hydraulic disc brake, the master cylinder comprising:

• a housing defining a cylinder, the cylinder having a first and a second end along its axis;
• a hydraulic fluid reservoir with a port between the hydraulic fluid reservoir and the cylinder, the port having an opening between the first and second cylinder ends;
• a piston having a seal between the cylinder and the piston, the seal having a leading seal edge, the leading seal edge being movable relative to the port opening to vary a dead band distance between the leading seal edge and the port opening with the piston in an unactuated position;
• a one piece lever pivotably associated with the housing and operatively associated with the piston for moving for piston within the cylinder between an unactuated and an actuated position as the lever is actuated between a rest position and an actuated position;
• a reach adjustment operatively associated with the lever for varying the rest position of the lever relative to the master cylinder housing independent of movement of the leading seal edge relative to the hole as the reach adjustment varies the rest position of the lever.

A master cylinder for a bicycle hydraulic disc brake, the master cylinder comprising:

• a housing defining a cylinder, the cylinder having a first and second end;
• a hydraulic fluid reservoir;
• a port between the hydraulic fluid reservoir and the cylinder providing fluid communication between the hydraulic fluid reservoir and the cylinder, the port having a port opening located between the first and second ends of the cylinder;
• a piston received in the cylinder having a seal operatively associated therewith, the seal having a leading edge, the leading seal edge being moveable between a select starting position with the leading seal edge between the first end and the port opening with the leading seal edge a select distance from the port opening and a pressurized position with the leading seal edge between the port opening and the second end, the leading seal edge preventing fluid flow between the cylinder and the reservoir when positioned between the port opening and the second end to pressurize the second end;
• a one piece lever pivotably attached to the housing, the lever being associated with the piston to move the piston between the select starting position and the pressurized position as the lever is pivoted between the rest position and a fully actuated position.