Automatic brake adjuster and reset having extensionable feature

Claim 1

Automatic brake adjusting and reset apparatus for a multiple disc disc brake having an axially movable fluid pressure actuated pressure plate for applying the brake comprising: an annular housing provided with a plurality of circumferentially spaced-apart cavities; a first radially deformable tubular member disposed in each of said cavities and provided with a stop member adjacent one end thereof; a second radially deformable tubular member coaxial with said first tubular member and adapted to telescope relative thereto; a support member fixedly secured to said pressure plate and extending therefrom into each of said cavities; a first deforming member fixedly secured to said support member and frictionally engaged with said first tubular member for deforming the same in response to axial movement thereof; a second deforming member interposed between said first and second tubular members and frictionally engaged with said second tubular member for deforming the same in response to axial movement therethrough; first and second spaced-apart fixed stop means engageable with said second tubular member and defining brake released and brake applied positions thereof; resilient means operatively connected to said second tubular member for urging the same into engagement with said first stop means; said first and second tubular members being actuated by said pressure plate in response to pressurization of the latter to apply the brake; said second tubular member engaging said second stop means to prevent subsequent movement of said first and second tubular members whereupon said first deforming member is urged axially through said first tubular member to the extent permitted by said stop member to progressively compensate for wear of the frictional surfaces of said multiple discs; said second deforming member being urged axially through said second tubular member by said first tubular member following engagement of said first deforming member with said stop member to extend the range of adjustment of said pressure plate beyond that provided by said first tubular member; said resilient means urging said second tubular member off said second stop means into engagement with said first stop means to thereby establish a predetermined brake running clearance upon depressurization of said pressure plate and release of said brake.