Patent ID: 7044566

Claim:
A master cylinder for use in a brake system having a housing with a first piston and a second piston positioned in a bore therein by first and second resilient means to define limits for a first chamber and a second chamber, said first and second chambers being connected to a reservoir through a compensation valves to receive fluid and maintain a fluid in said brake system at a desired level and being connected to front and rear wheel brakes to supply pressurized fluid to effect a brake application, said first and second resilient means each including a first retainer and a second retainer for caging a spring to establish a distance between said first and second pistons a face on a head of a stem of a corresponding compensation valve when in a rest position, said head on each compensation valve being moved into engagement with a seat on initial movement of said pistons from said rest position in response to an input force to terminate communication of fluid from said reservoir such that with further movement of said pistons fluid is pressurized in said chambers to initiate a brake application, said first retainer being characterized by a disc having a flange that surrounds an axial opening and wherein said second retainer is characterized by a cylindrical member having a convoluted peripheral surface adjacent a first end and a plurality of axial slots that extend from a second end toward said first end to define a plurality of fingers with an inward flange, said first end of said second retainer being located in an axial bore within a piston and retained therein by a ball exerting a force on said cylindrical member that forces said convoluted peripheral surface into engagement with said piston to fix said second retainer to said piston, said spring being located between said first retainer and said piston such that said head of stem of the compensation valve engages said first retainer and when an initial force is applied to said head of said stem while said piston is held stationary said spring is compressed and a radial projection on said stem after passing through said flange on said first retainer passes through said inward flange on said second retainer and on termination of said initial force the expansion of said spring is limited as said radial projection thereon engages said inward flange on said second retainer to set said distance.