GB812703A - Automatic brake adjustment mechanism - Google Patents

Abstract

812,703. Automatic adjustment mechanism for brakes. GOODYEAR TIRE & RUBBER CO. April 16, 1956 [Oct. 6, 1955], No. 11476/56. Class 103(1). In an automatic brake adjustment mechanism for a brake actuated by a piston and cylinder mechanism, a smooth cylindrical adjustment pin 21 is secured to a cylinder closure member 15 and extends axially within the cylinder, friction gripping means 32 being provided within the hollow brake piston 10 holding the pin against relative axial movement during normal travel of said piston or brake engagement but permitting movement when the friction lining wear occurs. In the applied position of the spot-type disc brake illustrated, an axially slidable brake disc 4 is rotatable with wheel 1 and is frictionally engaged by friction pads 11 when the cylinder 12 is pressurized to force the piston and disc axially into frictional contact with friction pad 9 secured to the stationary housing 8. The automatic adjusting mechanism consists of a coiled spring 31 mounted about a bushing 28 with one end abutting piston 18 and the open end abutting flange 30. A spacer sleeve 33 loosely encompasses the pin 21 between the friction collar 32 and the part 17 of the piston and the length of spacer sleeve is less than the axial space 20 of the piston less the thickness of flange 29 and width of collar 32 by an amount equal to the normal piston movement during a brake application. With the parts shown in the brake applied positions in Fig. 1 the clearance between the end of the sleeve 33 and the piston wall 17 provides normal operating clearance and upon release of brake pressure spring 31 moves the piston 10 to the left to bring piston wall 17 into engagement with sleeve 33 to reestablish normal clearance between disc 4 and friction pads 9 and 11. The arrangement is such that should the piston move the desired amount without the brake being applied, the friction collar 32 will then be forced along the pin 21 to a new position where the brake block 11 will engage the disc 4. In a further embodiment disclosed in Fig. 3, a smooth pin 73 housed in a disc member 67 closing the end of a cylinder 62 in the non-rotatable brake support. The head 74 of pin 73 has a limited movement axially relative to the disc member 67 against the resistance of a spring member 75 to provide the normal operating clearance of the brake. The piston 63 is provided with a split spring ring 79 mounted, whilst under tension, on the pin 73 such that when the piston 63 is moved axially of the cylinder under fluid pressure, the pin 73 is moved with the piston 63 to the limit permitted by the clearance between the head 74 of the pin and its confining elements; denoting normal brake clearance. Should such movement be insufficient to permit application of the brake, the piston will be moved along the pin against the frictional resistance of the split spring ring 79 to a new position where friction pads engage the brake disc 61.