Automatic slack adjuster

Claim 2

In an actuator for a brake: a drive shaft for actuating said brake; a lever including a housing mounted on said drive shaft for actuating said drive shaft; said lever being movable in brake actuation and brake release directions; an adjustment shaft rotatably mounted within said housing and drivingly interconnected with said drive shaft to rotate the latter relative to said housing in a direction to effect brake adjustment when the adjustment shaft is rotated in a brake adjustment effecting direction, said adjustment shaft rotating said drive shaft in the opposite direction to back off said brake when the adjustment shaft is rotated in the opposite direction; means on said adjustment shaft accessible from the exterior of said housing for manually effecting rotation of said adjustment shaft in either direction; and automatic adjustment means connected with said adjustment shaft for rotating the latter in said brake adjustment effecting direction only upon movement of said lever in the brake actuation direction when the stroke of the lever exceeds a predetermined amount; said automatic adjustment means including clutch means releasably connecting said automatic adjustment means for rotation of said shaft, said clutch means disconnecting said adjustment shaft and said automatic adjustment means when manual rotation of said adjustment shaft in either direction is effected.

Claim 3

The invention of claim 1: said adjustment means including a crank sleeve rotatably mounted on said adjustment shaft, means for rotating said crank sleeve in a brake adjustment effecting direction as the lever is moved in the brake actuating direction, a drive sleeve drivingly connected with said adjustment shaft, said clutch means interconnecting said sleeves but permitting relative rotation between the adjustment shaft and the crank sleeve when the torque applied to the clutch means exceeds a predetermined amount.

Claim 4

The invention of claim 2: said clutch means transmitting a predetermined torque level before permitting relative rotation between the adjustment shaft and the crank sleeve when the latter is rotated in the brake adjustment effecting direction and permitting relative rotation between the adjustment shaft and the crank sleeve when the latter is rotated in the opposite direction.

Claim 5

The invention of claim 3; and second clutch means engaging said adjustment shaft permitting rotation of the latter in said brake adjustment effecting direction but impeding rotation of the adjustment shaft in the opposite direction.

Claim 6

In an actuator for a brake: a drive shaft for actuating said brake; a lever including a housing mounted on said drive shaft for actuating the latter, said lever being movable in brake actuation and brake release directions; an adjustment shaft member rotatably mounted within said housing and drivingly interconnected with said drive shaft to rotate said drive shaft relative to saiD housing in a direction to effect brake adjustment; and automatic adjustment means operably connected with said adjustment shaft member for rotating the latter in said direction effecting brake adjustment upon movement of the lever in the brake actuating direction when the stroke of the lever exceeds a predetermined amount; said automatic adjustment means including crank means, means for rotating said crank means in a brake adjustment effecting direction as the lever is moved in the brake actuating direction, a drive member drivingly connected with the adjustment shaft, and clutch means coupling said drive member with said crank means when the latter is rotated in said brake adjustment effecting direction but uncoupling the crank means and the drive member when the crank means is rotated in the opposite direction; said crank means including a crank sleeve rotatably mounted on said adjustment shaft, said drive means including a drive sleeve operably connected with said adjustment shaft, said clutch means including an actuation coil spring, said sleeves being received in opposite ends of said actuation coil spring, the diameters of said sleeves being greater than the relaxed diameter of the actuation coil springs to create an interference fit between the spring and the sleeves so that the actuation spring grippingly engages the sleeves, the diameter of said crank sleeve being greater than the diameter of said drive sleeve so that the strength of the interference fit between the actuation spring and the crank sleeve is greater than the strength of the interference fit between the actuation spring and the drive sleeve.

Claim 7

In an actuator for a brake: a drive shaft for actuating said brake; a lever including a housing mounted on said drive shaft for actuating the latter, said lever being movable in brake actuation and brake release directions; an adjustment shaft member rotatably mounted within said housing and drivingly interconnected with said drive shaft to rotate said drive shaft relative to saiD housing in a direction to effect brake adjustment; and automatic adjustment means operably connected with said adjustment shaft member for rotating the latter in said direction effecting brake adjustment upon movement of the lever in the brake actuating direction when the stroke of the lever exceeds a predetermined amount; said automatic adjustment means including crank means, means for rotating said crank means in a brake adjustment effecting direction as the lever is moved in the brake actuating direction, a drive member drivingly connected with the adjustment shaft, and clutch means coupling said drive member with said crank means when the latter is rotated in said brake adjustment effecting direction but uncoupling the crank means and the drive member when the crank means is rotated in the opposite direction; said crank means including a crank sleeve rotatably mounted on said adjustment shaft, said drive means including a drive sleeve operably connected with said adjustment shaft, said clutch means including an actuation coil spring, said sleeves being received in opposite ends of said actuation coil spring, the diameters of said sleeves being greater than the relaxed diameter of the actuation coil springs to create an interference fit between the spring and the sleeves so that the actuation spring grippingly engages the sleeves, the diameter of said crank sleeve being greater than the diameter of said drive sleeve so that the strength of the interference fit between the actuation spring and the crank sleeve is greater than the strength of the interference fit between the actuation spring and the drive sleeve.

Claim 8

The invention of claim 5; and a lost motion connection between said drive member and said adjustment shaft member to permit a predetermined amount of relative rotation between the drive means and the adjustment shaft before adjustment is effected.

Claim 9

The invention of claim 6: said lost motion connection including axially extending splines on one of said members and mating grooves on the other member receiving said splines, the width of said splines being less than the width of the grooves to permit relative rotation between the members until the splines engage the sides of the groove.

Claim 10

The invention of claim 5: said actuation coil spring being wound so that when the spring is torqued by rotation of the crank means in the brake adjustment effecting direction the diameter of the actuation spring decreases to thereby increase the strength of the interference fit between sleeves and the spring, the diameter of the actuation spring increasing as the latter is torqued by rotation of the crank in the opposite direction, whereby the actuation spring slips on said drive sleeve.

Claim 11

The invention of claim 8; and an antireverse coil spring wound opposite to the actuation coil spring and receiving one end of said adjustment shaft, whereby upon rotation of the latter in said brake adjustment effecting direction the diameter of said antireverse spring increases to permit rotation of the shaft relative to the antireverse coil spring, and when rotation of the adjustment shaft in the opposite direction is attempted the diameter of the antireverse spring decreases to grippingly engage the adjustment shaft to prevent rotation of the latter in said opposite direction.

Claim 12

In an actuator for a brake: a drive shaft for actuating said brake; a lever including a housing mounted on said drive shaft for actuating the latter, said lever being movable in brake actuation and brake release directions; an adjustment shaft rotatably mounted within said housing and drivingly interconnected with said drive shaft to rotate said drive shaft relative to said housing in a direction to effect brake adjustment when the adjustment shaft is rotated in the brake adjustment effecting direction; automatic adjustment means operably connected with said adjustment shaft for rotating the latter in said direction effecting brake adjUstment upon movement of the lever in the brake actuating direction when the stroke of the lever exceeds a predetermined amount; said automatic adjustment means including means rotatable in a brake adjustment effecting direction when the lever is moved in the brake actuating direction and in the opposite direction as the lever is moved in the release direction, first clutch means drivingly connecting the adjustment shaft with said rotatable means when the latter is rotated in said brake adjustment effecting direction but permitting the rotatable means to rotate relative to the adjustment shaft when the rotatable means is rotated in the opposite direction, and second clutch means permitting said automatic adjustment means to rotate said adjustment shaft in said brake adjustment effecting direction but grippingly engaging said adjustment shaft to prevent rotation of the latter when the rotatable means is rotated in said opposite direction.

Claim 13

In an actuator for a brake: a drive shaft for actuating said brake; a lever including a housing mounted on said drive shaft for actuating the latter, said lever being movable in brake actuation and brake release directions; an adjustment shaft rotatably mounted within said housing and drivingly interconnected with said drive shaft to rotate said drive shaft relative to said housing in a direction to effect brake adjustment when the adjustment shaft is rotated in the brake adjustment effecting direction; automatic adjustment means operably connected with said adjustment shaft for rotating the latter in said direction effecting brake adjUstment upon movement of the lever in the brake actuating direction when the stroke of the lever exceeds a predetermined amount; said automatic adjustment means including means rotatable in a brake adjustment effecting direction when the lever is moved in the brake actuating direction and in the opposite direction as the lever is moved in the release direction, first clutch means drivingly connecting the adjustment shaft with said rotatable means when the latter is rotated in said brake adjustment effecting direction but permitting the rotatable means to rotate relative to the adjustment shaft when the rotatable means is rotated in the opposite direction, and second clutch means permitting said automatic adjustment means to rotate said adjustment shaft in said brake adjustment effecting direction but grippingly engaging said adjustment shaft to prevent rotation of the latter when the rotatable means is rotated in said opposite direction.

Claim 14

The invention of claim 10: said automatic adjustment means including crank means rotatable relative to said adjustment shaft means for rotating said crank means in a brake adjustment effecting direction as said lever is moved in the brake actuating direction, drive means drivingly connected to said adjustment shaft, said first clutch means being a coiled spring interconnecting the drive means and the crank means, said coiled spring being wound so that the spring slips relative to the drive means at a predetermined torque level when the crank means is rotated in the brake adjustment effecting direction and permits relative rotation between the drive means and the crank means when the crank means is rotated in the opposite direction.

Claim 15

The invention of claim 11: said second clutch means being a second coiled spring wound opposite from the clutch spring comprising said first clutch means, said second coiled spring engaging said adjustment shaft to permit the latter to rotate in said brake adjustment effecting direction, but impeding rotation of said adjustment shaft in the reverse direction.