Brake master cylinder cup seal with valve

Claim 2

In a brake master cylinder having piston means slidably disposed within cylinder means, said cylinder means including fluid inlet and outlet means, a sealing arrangement for said piston means comprising; a resilient cup seal freely movable relative to said piston means and not carried thereupon disposed within said cylinder means between said fluid outlet means and said piston means, said resilient cup seal being transpierced by centrally-disposed fluid passageway means, valve means mounted within said fluid passageway means for closing off said passageway means when said resilient cup seal is in a first predetermined position with respect to said piston means and for permitting unrestricted fluid flow through said passageway means when said resilient cup seal is disposed in a second predetermined position with respect to said piston means, first spring means for biasing said valve means toward said piston means, a retainer member adapted to engage said first spring means, and said retainer member being fixed to and movable with said valve means.

Claim 3

The invention of claim 1 wherein said valve means include a poppet valve having an enlarged head portion and a stem portion, said passageway means including a contoured counterbore seat portion adapted to engage said enlarged head portion when said resilient cup seal is disposed in said first predetermined position.

Claim 4

The invention of claim 1 wherein said valve means include a valve having a hollow body and a plurality of radial passages communicating the interior and exterior of said body and wherein a portion of said passageway means engages and closes off said radial passages when said resilient cup seal is disposed in said first predetermined position and opens said radial passages when said resilient cup seal is disposed in said second predetermined position.

Claim 5

The invention of claim 1 wherein said valve means include a valve member having an enlarged portion and an elongated stem portion, said elongated stem portion being slidably disposed within said passageway means, said enlarged portion having a plurality of arcuately spaced axial bores therethrough, said stem portion having a plurality of arcuately spaced axial grooves therein in direct communication with said axial bores, and all of said axial grooves being simultaneously closed off by said piston means when said resilient cup seal is disposed in said first predetermined position.

Claim 6

The invention of claim 1 wherein said retainer member directly engages said resilient cup seal when said resilient cup seal is disposed in said second predetermined position, said retainer member having passage means therethrough for permitting said unrestricted fluid flow through said fluid passageway means when said resilient cup seal is disposed in said second predetermined position.

Claim 7

The invention of claim 1 wherein said cylinder means include a cylindrical bore formed within a housing member and a fluid supply reservoir, and wherein first and second port means are provided for communicating said bore with said fluid supply reservoir.

Claim 8

The invention of claim 6 wherein said first and second port means include respectively a compensating port and a fluid make-up port spaced axially apart from one another along said bore and whErein said outlet means is disposed at one axial end of said bore.

Claim 9

The invention of claim 2 wherein said poppet valve is slidably disposed within said fluid passageway means, and wherein said stem portion is in constant engagement with a portion of said resilient cup seal.

Claim 10

The invention of claim 8 wherein said stem portion is provided with flat areas of reduced dimension to permit unrestricted fluid flow through said fluid passageway means past said stem portion disposed therein.

Claim 11

In a brake master cylinder having a main bore with an outlet end, a reservoir adjacent to said main bore, a fluid make-up port communicating said bore with said reservoir, a piston having a flange portion slidably disposed within said main bore between said make-up port and said outlet end, passage means transpiercing said flange portion, and biasing means within said main bore for urging said piston toward said make-up port, a piston sealing arrangement comprising; a flexible free-floating seal member having a passageway therethrough slidably disposed in said main bore adjacent to said flange portion and separate therefrom, valve means disposed within said passageway and movable with said seal member and also relative thereto, said valve means including retainer means for directly engaging said biasing means, said valve means operative to close said passageway when said seal member is disposed in a first predetermined position with respect to said flange portion and operative to permit fluid flow from said reservoir through said make-up port and passage means and through said passageway when said seal member is disposed in a second predetermined position with respect to said flange portion.

Claim 12

In a brake master cylinder having a main bore with an outlet end, a reservoir adjacent to said main bore, a fluid make-up port communicating said bore with said reservoir, a piston having a flange portion slidably disposed within said main bore between said make-up port and said outlet end, passage means transpiercing said flange portion, and biasing means within said main bore for urging said piston toward said make-up port, a piston sealing arrangement comprising; a flexible free-floating seal member having a passageway therethrough slidably disposed in said main bore adjacent to said flange portion and separate therefrom, valve means disposed within said passageway and movable with said seal member and also relative thereto, said valve means including retainer means for directly engaging said biasing means, said valve means operative to close said passageway when said seal member is disposed in a first predetermined position with respect to said flange portion and operative to permit fluid flow from said reservoir through said make-up port and passage means and through said passageway when said seal member is disposed in a second predetermined position with respect to said flange portion.