Adjustable disc brake push rod

Claim 2

In a brake actuating means for a vehicle brake system: a hydraulic actuator including two opposed relatively axially displaceable actuator components defining a space therebetween for brake fluid; and an automatic adjuster including a push rod, a nut having a screw thread connection with said push rod, on of said actuator components being nonrotatable and having therethrough an opening of noncircular cross section, said push rod having a portion of complementary noncircular cross section and axially slidably guided through said opening, a resilient sealing member sealing said push rod to said opening, and means responsive to excess travel between said actuator components for turning said nut in a direction to compensate for such excess travel.

Claim 3

The brake actuating means according to claim 1 further comprising a mechanical actuator fitted to said one hydraulic actuator component and acting on the end of said push rod opposite said nut.

Claim 4

In a brake actuating means for a vehicle brake system: hydraulic actuating means having a piston; and a mechanism of adjustable length comprising a push rod and a nut having a screw thread connection with said push rod, said nut being disposed for frictional engagement with said piston and said push rod being subjected to the hydraulic pressure applied to the piston but in the opposite direction thereto, said actuating means also including a nonrotatable member having an opening of non circular cross section, said push rod having a portion of complementary non circular cross section and slidably guided in said opening, a resilient sealing member sealing said push rod to said opening, and a further member in axial and rotational engagement with said nut through at least one helically inclined surface, whereby after a predetermined travel of said actuating means has occurred the nut is rotated to increase the length of the mechanism of adjustable length.

Claim 5

In a brake actuating means for a vehicle brake system: hydraulic actuating means having a piston; and a mechanism of adjustable length comprising a push rod and a nut having a screw thread connection with said push rod, said nut being disposed for frictional engagement with said piston and said push rod being subjected to the hydraulic pressure applied to the piston but in the opposite direction thereto, said actuating means also including a nonrotatable member having an opening of non circular cross section, said push rod having a portion of complementary non circular cross section and slidably guided in said opening, a resilient sealing member sealing said push rod to said opening, and a further member in axial and rotational engagement with said nut through at least one helically inclined surface, whereby after a predetermined travel of said actuating means has occurred the nut is rotated to increase the length of the mechanism of adjustable length.

Claim 6

The brake actuating means according to claim 3, in which said nonrotatable member of said actuator comprises a nonrotatable second piston opposed to the first-mentioned piston.

Claim 7

In a brake actuating means for a vehicle brake system: a mechanism of adjustable length comprising a push rod and a nut having a screw thread connection with said push rod, the coefficient of friction between one flank of the screw thread on the push rod and the mating screw thread flank on the nut being comparatively high and the coefficient of friction between the other thread flank on the push rod and its mating flank on the nut being comparatively low, a nonrotatable guide member having an opening of non circulaR cross section, said push rod having a portion of complementary non circular cross section and slidably guided in said opening, and a resilient sealing member sealing said push rod to said opening.

Claim 8

In a brake actuating means for a vehicle brake system: a mechanism of adjustable length comprising a push rod and a nut having a screw thread connection with said push rod, the coefficient of friction between one flank of the screw thread on the push rod and the mating screw thread flank on the nut being comparatively high and the coefficient of friction between the other thread flank on the push rod and its mating flank on the nut being comparatively low, a nonrotatable guide member having an opening of non circulaR cross section, said push rod having a portion of complementary non circular cross section and slidably guided in said opening, and a resilient sealing member sealing said push rod to said opening.

Claim 9

In a brake actuating means for a vehicle brake system: a mechanism of adjustable length comprising push rod and a nut having a screw thread connection with said push rod, a non rotatable guide member having an opening of non circular cross section, said push rod having a portion of complementary non circular cross section and slidably guided in said opening, a resilient sealing member sealing said push rod to said opening, and a friction clutch or brake associated with said nut and provided with means effective responsively to a requirement for adjustment for causing a relative back and forth turning movement between one part of said rotary friction clutch or brake and said push rod when said screw thread connection is under an axial load in one direction, the slip torque of said friction clutch or brake being greater than the lower frictional torque arising at said screw thread connection when turned in a direction with said axial load but less than the higher frictional torque arising at said screw thread connection when turned in a direction against said axial load, whereby said relative back and forth turning movement causes a relative turning movement of the nut on the push rod in one direction only.

Claim 10

In a brake actuating means for a vehicle brake system: a mechanism of adjustable length comprising push rod and a nut having a screw thread connection with said push rod, a non rotatable guide member having an opening of non circular cross section, said push rod having a portion of complementary non circular cross section and slidably guided in said opening, a resilient sealing member sealing said push rod to said opening, and a friction clutch or brake associated with said nut and provided with means effective responsively to a requirement for adjustment for causing a relative back and forth turning movement between one part of said rotary friction clutch or brake and said push rod when said screw thread connection is under an axial load in one direction, the slip torque of said friction clutch or brake being greater than the lower frictional torque arising at said screw thread connection when turned in a direction with said axial load but less than the higher frictional torque arising at said screw thread connection when turned in a direction against said axial load, whereby said relative back and forth turning movement causes a relative turning movement of the nut on the push rod in one direction only.

Claim 11

In a brake actuating means for a vehicle brake system: a mechanism of adjustable length comprising a push rod and a nut having a screw thread connection with said push rod, a non rotatable guide member having an opening of non circular cross section, said push rod having a portion of complementary noncircular cross section and slidably guided in and through said opening a resilient sealing member sealing said push rod to said opening, and a mechanical actuator acting on the end of said push rod opposite said nut.

Claim 12

In a brake actuating means for a vehicle brake system: a mechanism of adjustable length comprising a push rod and a nut having a screw thread connection with said push rod, a non rotatable guide member having an opening of non circular cross section, said push rod having a portion of complementary noncircular cross section and slidably guided in and through said opening a resilient sealing member sealing said push rod to said opening, and a mechanical actuator acting on the end of said push rod opposite said nut.

Claim 13

In the brake actuating means according to claim 7: a hydraulic actuator, said non rotatable guide member comprising a piston of said actuator, said mechanical actuator including a cam journaled in said piston.