Automatic brake adjuster mechanism

Claim 2

In a brake having an axially fixed member and an axially movable member which moves a distance at least partially dependent upon the amount of brake wear, an automatic adjuster mechanism for automatically changing the released position of said axially movable member to maintain a predetermined brake clearance comprising axially extending positioning means secured to said axially movable member, first and second fixed stop means operatively connected to said fixed member, follower means axially movable between said first and second stop means, resilient means compressed between said follower means and fixed abutment means carried by said fixed member, first and second variable volume chamber means formed by said positioning means and said follower means for defining fluid like means, said fluid like means having a constant volume of incompressible fluid divided between said first and second chamber means for permitting concomitant and equal axial movement of said positioning means and said follower means during a brake application until said follower means has moved from said first to said second stop means, and valve means operatively connected to said positioning and follower means for permitting independent axial movement of said positioning means relative to said follower means thereafter by allowing flow of fluid from said first chamber means to said second chamber means but preventing reverse flow therebetween, said fluid in said second chamber means being trapped therein by said valve means so that the axial relationship between said positioning means and said follower means will be changed for the next brake application.

Claim 3

The structure, as defined in claim 1, wherein said positioning means includes a cylinder member and said follower means includes a piston member located therein and in sealing engagement therewith.

Claim 4

The structure, as defined in claim 2, wherein said first chamber means is located within said cylinder member and on one side of said piston member and said second chamber means is located within said cylinder member and on the other side of said piston member.

Claim 5

The structure, as defined in claim 3, wherein said valve means is located in one of said cylinder and piston members.

Claim 6

The structure, as defined in claim 4, wherein said valve means is located in said piston member.

Claim 7

The structure, as defined in claim 5, wherein said valve means is a check valve which upon fluid flow from said first chamber means to said second chamber means traps fluid in said second chamber means.

Claim 8

The structure, as defined in claim 6, wherein said follower means includes a piston rod connected to said piston member which extends exteriorly of said cylinder member and a contact member connected to said piston rod which limits movement of said follower means between said first and second stop means.

Claim 9

The structure, as defined in claim 7, wherein said resilient means is a return spring which is confined between the fixed abutment means of said fixed member and said contact member.

Claim 10

The structure, as defined in claim 8, wherein said contact member is a washer which is retained on said piston rod.

Claim 11

The structure, as defined in claim 9, wherein said washer is retained on said piston rod by a nut threaded thereon.

Claim 12

In a brake having an axially fixed member and an axially movable member which moves a distance at least partially dependent upon the amount of brake wear, an automatic-adjuster mechanism for automatically changing the released position of said axially movable member to maintain a predetermined brake clearance comprising axially extending positioning means secured to said axially movable member, said positioning means including a cylinder member, first and second fixed stop means operatively connected to said fixed member, axially movable spring follower means, said follower means including a piston member located within said cylinder member in sealing engagement therewith and having a piston rod extending therefrom with a washer retained on the end thereof, said washer being adapted to limit movement of said follower means between said first and second stop means, fluid link means located within said cylinder member and having a constant volume of incompressible fluid for permitting concomitant and equal axial movement of said positioning means and said follower means during a brake application until said washer has moved from said first to said second stop means, said fluid link means including a first variable volume chamber located on one side of said piston member and a second variable volume chamber located on the other side of said piston member, and valve means located in said piston member for permitting independent axial movement of said positioning means relative to said follower means thereafter by allowing fluid flow from said first chamber means to said second chamber means and then trapping said fluid in said second chamber means so that the axial relationship between said positioning means and said follower means will be changed for the next brake application.

Claim 13

In a brake having an axially fixed member and an axially movable member which moves a distance at least partially dependent upon the amount of brake wear, an automatic-adjuster mechanism for automatically changing the released position of said axially movable member to maintain a predetermined brake clearance comprising axially extending positioning means secured to said axially movable member, said positioning means including a cylinder member, first and second fixed stop means operatively connected to said fixed member, axially movable spring follower means, said follower means including a piston member located within said cylinder member in sealing engagement therewith and having a piston rod extending therefrom with a washer retained on the end thereof, said washer being adapted to limit movement of said follower means between said first and second stop means, fluid link means located within said cylinder member and having a constant volume of incompressible fluid for permitting concomitant and equal axial movement of said positioning means and said follower means during a brake application until said washer has moved from said first to said second stop means, said fluid link means including a first variable volume chamber located on one side of said piston member and a second variable volume chamber located on the other side of said piston member, and valve means located in said piston member for permitting independent axial movement of said positioning means relative to said follower means thereafter by allowing fluid flow from said first chamber means to said second chamber means and then trapping said fluid in said second chamber means so that the axial relationship between said positioning means and said follower means will be changed for the next brake application.