Spring-loaded adjustment mechanism for hydraulic disc brake

Claim 2

A wear-compensation adjustment mechanism for a hydraulic brake, said mechanism comprising: an adjustment member rotatable in one sense to adjust said brake; a spiral spring for rotating said member in said one sense; and hydraulically actuatable blocking means engageable with said spring for rendering same ineffective for rotating said member on hydraulic actuation of said brake, said brake being a disc brake having a housing forming a cylinder, a piston movable in said cylinder, and restoring means for reestablishing brake play upon hydraulic actuation of said piston, said adjustment member being a threaded spindle threadedly engaged with said piston for displacing same in one axial direction thereof to adjust said brake, said restoring means acting upon said piston in the other axial direction, said spiral spring being anchored at its inner end to said threaded spindle.

Claim 3

The mechanism defined in claim 1 wherein said return means is a roll-back seal received in said cylinder and surrounding said piston while frictionally engaging same.

Claim 4

A wear-compensation adjustment mechanism for a hydraulic brake, said mechanism comprising: an adjustment member rotatable in one sense to adjust said brake; a spiral spring for rotating said member in said one sense; and hydraulically actuable blocking means engageable with said spring for rendering same ineffective for rotating said member on hydraulic actuation of said brake; the mechanism defined in claim 2 wherein said blocking means being a second piston exposed to fluid pressure in said cylinder and engageable with said spiral spring to clamp it upon hydraulic pressurization of said cylinder.

Claim 5

The mechanism defined in claim 3, further comprising spring means urging said second piston away from said spiral spring.

Claim 6

The mechanism defined in claim 4 wherein said spring means is a dished-disc washer.

Claim 7

The mechanism defined in claim 4 wherein said spring means is a coil compression spring.

Claim 8

The mechanism defined in claim 6, further comprising an abutment in said cylinder, said second piston being engageable with said abutment under the force of said coil compression spring.

Claim 9

The mechanism defined in claim 3 wherein said second piston is annular and surrounds said spindle and, said spiral spring is substantially planar and surrounds said spindle while extending radially therebeyond into the path of said second piston.

Claim 10

The mechanism defined in claim 8 wherein said disc brake comprises further a brake disc rotatable relatively to said housing, a pair of brakeshoes flanking said disc on opposite sides thereof, said first piston bearing upon one of said brakeshoes proximal to said cylinder, a third piston axially shiftable in said cylinder and displaceable upon hydraulic pressurization thereof in a direction opposite the direction of displacement of said first piston by said hydraulic pressurization, and force-transmitting means between said third piston and the other of said brakeshoes for drawing same against said disc, said third piston being generally cup-shaped and opening in the direction of said first piston while slidably receiving said second piston and having a closed end turned away from said first piston, said spiral spring being disposed between said closed end and said second piston.

Claim 11

The mechanism defined in claim 9 wherein said spindle passes axially through said closed end of said third piston, said brake further comprising mechanical actuating means interposed between said force-transmitting means and said spindle for actuating said brake independently of hydraulic pressurization of said cylinder.