Brake actuator and adjuster mechanism

Claim 2

In a disc brake actuator and adjuster mechanism: a brake actuating piston having a clutch cone rotatably and slidably received therein and a clutch therebetween; an adjuster nut slidably received in said clutch cone; a rotatable brake apply shaft on which said adjuster nut is threaded; and spring means acting between said piston and said clutch cone with a predetermined prelOad holding said clutch in engagement, said preload being less than the force required to lock said clutch against relative rotational movement of said piston and said clutch cone; said spring means also acting between said piston and said adjuster nut with a predetermined preload urging said adjuster nut into axial force transmitting engagement with said clutch cone; rotating movement of said apply shaft in the brake apply direction increasing the axial force from said adjuster nut to said clutch cone and thereby increasing the clutch means engaging force between said clutch cone and said piston to a force greater than said clutch means locking force to lock said clutch cone to said piston against relative rotational movement and moving said piston to apply the brake; rotating movement of said apply shaft in the brake release direction removing the brake apply force through said clutch means until the clutch means engaging force is less than said clutch means locking force and said clutch means permits rotating movement of said clutch cone concurrently with said adjuster nut on said apply shaft under the force of said spring means exerted on said adjuster nut to move said adjuster nut axially into engagement with said clutch cone to adjust the brake; and means subjecting said piston and said clutch cone to brake actuating fluid pressure to apply the brake independently of actuation of the apply shaft.

Claim 3

A disc brake actuator and adjuster mechanism comprising: a cylinder body; a piston slidably and sealingly received in said cylinder body and having means preventing piston rotation in said cylinder body and a clutch cone rotatably and slidably received in said piston and axially engageable therewith in clutching relation; an adjuster nut slidably mounted in said clutch cone in relative non-rotatable relation and axially engageable therewith in axial force transmitting relation; a threaded member mounted on said cylinder body and having said adjuster nut threaded thereon; said cylinder body cooperating with said piston and said clutch cone to define a brake pressure actuating chamber; spring means acting between said piston and said clutch cone with a predetermined preload holding said clutch cone in clutch-slippable engagement with said piston, said spring means further acting between said clutch cone and said adjuster nut with a predetermined preload urging said adjuster nut toward axial force transmitting engagement with said clutch cone; and means supplying brake actuating fluid pressure to said brake pressure actuating chamber, said pressure acting on said piston and said clutch cone to actuate the brake and to increase the force holding said clutch cone in engagement with said piston above that required to prevent clutch slip, thereby locking said clutch cone against rotary movement relative to said piston; said spring means, upon release of the fluid pressure in said brake pressure actuating chamber sufficient to decrease the forces holding said clutch cone in engagement with said piston below that required to prevent clutch slip, acting on said adjuster nut to cause rotation of said adjuster nut on said threaded member and thereby rotate said clutch cone relative to said piston and to cause said adjuster nut to move axially to take up any axial slack between said adjuster nut and said clutch cone generated by piston and cone axial movement during brake actuation and to engage said clutch cone axially, thereby adjusting the brake.

Claim 4

A disc brake actuator and adjuster mechanism comprising: a cylinder body; a piston slidably and sealingly received in said cylinder body and having means preventing piston rotation in said cylinder body and a clutch cone rotatably and slidably received in said piston and axially engageable therewith in clutching relation; an adjuster nut slidably mounted in said clutch cone in relative non-rotatable relation and axially engageable therewith in axial force transmitting relation; a threaded member mounted on said cylinder body and having said adjuster nut threaded thereon; said cylinder body cooperating with said piston and said clutch cone to define a brake pressure actuating chamber; spring means acting between said piston and said clutch cone with a predetermined preload holding said clutch cone in clutch-slippable engagement with said piston, said spring means further acting between said clutch cone and said adjuster nut with a predetermined preload urging said adjuster nut toward axial force transmitting engagement with said clutch cone; and means supplying brake actuating fluid pressure to said brake pressure actuating chamber, said pressure acting on said piston and said clutch cone to actuate the brake and to increase the force holding said clutch cone in engagement with said piston above that required to prevent clutch slip, thereby locking said clutch cone against rotary movement relative to said piston; said spring means, upon release of the fluid pressure in said brake pressure actuating chamber sufficient to decrease the forces holding said clutch cone in engagement with said piston below that required to prevent clutch slip, acting on said adjuster nut to cause rotation of said adjuster nut on said threaded member and thereby rotate said clutch cone relative to said piston and to cause said adjuster nut to move axially to take up any axial slack between said adjuster nut and said clutch cone generated by piston and cone axial movement during brake actuation and to engage said clutch cone axially, thereby adjusting the brake.

Claim 5

A brake adjuster for a disc brake comprising: a normally non-rotatable brake force apply member axially movable in opposite directions to apply and release a disc brake and having a first clutch element thereon; a second clutch element rotatably and axially movably mounted in said brake force apply member and engaging said first clutch element in clutch-slippable relation and defining therewith a clutch; a threaded member having an adjuster member threadEd thereon for concurrent axial movement and rotary movement thereon, said adjuster member being axially engageable with said second clutch element in axial force transmitting relation; a spring having a first compression section acting between said brake force apply member and said second clutch element and preloaded to exert an axial force holding said second clutch element in clutch-slippable engagement with said first clutch element, said spring having a second compression section acting between said brake force apply member and said adjuster member and urging said adjuster member toward axial force transmitting engagement with said second clutch element; and means for actuating the brake by moving said brake force apply member and said second clutch element axially with an increase in axial force through said clutch at least sufficient to lock said clutch against slippage to prevent rotary movement of said second clutch element and said adjuster member relative to said piston, and to release the brake with a decrease in axial force through said clutch sufficient to permit rotary movement of said second clutch element and said adjuster member relative to said piston and to said threaded member under influence of said spring second compression section to cause axial movement of said adjuster member relative to said second clutch element to take up axial slack therebetween until said adjuster member engages said second clutch element in axial force transmitting relation.

Claim 6

A brake adjuster for a disc brake comprising: a normally non-rotatable brake force apply member axially movable in opposite directions to apply and release a disc brake and having a first clutch element thereon; a second clutch element rotatably and axially movably mounted in said brake force apply member and engaging said first clutch element in clutch-slippable relation and defining therewith a clutch; a threaded member having an adjuster member threadEd thereon for concurrent axial movement and rotary movement thereon, said adjuster member being axially engageable with said second clutch element in axial force transmitting relation; a spring having a first compression section acting between said brake force apply member and said second clutch element and preloaded to exert an axial force holding said second clutch element in clutch-slippable engagement with said first clutch element, said spring having a second compression section acting between said brake force apply member and said adjuster member and urging said adjuster member toward axial force transmitting engagement with said second clutch element; and means for actuating the brake by moving said brake force apply member and said second clutch element axially with an increase in axial force through said clutch at least sufficient to lock said clutch against slippage to prevent rotary movement of said second clutch element and said adjuster member relative to said piston, and to release the brake with a decrease in axial force through said clutch sufficient to permit rotary movement of said second clutch element and said adjuster member relative to said piston and to said threaded member under influence of said spring second compression section to cause axial movement of said adjuster member relative to said second clutch element to take up axial slack therebetween until said adjuster member engages said second clutch element in axial force transmitting relation.

Claim 7

Disc brake actuating and adjusting mechanism comprising: a caliper housing having first and second brake pad assemblies positioned on opposite sides of a disc to be braked; a first piston sealingly slidable in said housing and engaging said first brake pad assembly, said second brake pad assembly being mounted on said housing, and both of said brake pad assemblies being in brake torque transmitting relation to said housing; means preventing rotation of said first piston in said housing and operable to permit rotation of said first piston in said housing and including at least a part of said first brake pad assembly; a second piston sealingly slidable in said first piston and cooperating with said first piston and said housing to define a brake actuating pressure chamber; clutch means acting between said first and second pistons and being normally engaged to resist rotary movement of said second piston relative to said first piston and providing an axial force transmitting connection between said first and second pistons when engaged; an adjuster nut normally in axial force transmitting engagement with said second piston; means axially slidably connecting said adjuster nut and said second piston and preventing relative rotary movement therebetween; shaft means rotatably mounted in said housing and extending axially into said chamber and threadedly engaging said adjuster nut and generating axial movement of said adjuster nut when rotated to actuate the brake through said pistons and said clutch means; means for introducing brake actuating fluid pressure into said chamber to urge said first and second pistons toward the disc to actuate the brake; and a marcelled spring having a first section acting between said first and second pistons and urging said clutch means into engagement with a predetermined preload, and a second section acting between said first piston and said adjuster nut and urging said adjuster nut axially toward axial force transmitting engagement with said second piston; said spring second section acting upon brake release to move said adjuster nut rotationally on said shaft means and thereby imparting axial movement thereto to axially take up any space between said adjuster nut and said second piston caused by brake wear taken up by axial movement of said first and second pistons during brake actuation; said first piston rotation preventing means, when operated to permit rotation of said first piston in said housing, Permitting concurrent rotation of said first and second pistons and said adjuster nut to thread said adjuster nut on said shaft means axially away from the disc to reset said pistons and said adjuster nut for installation of new brake shoe assemblies.

Claim 8

Disc brake actuating and adjusting mechanism comprising: a caliper housing having first and second brake pad assemblies positioned on opposite sides of a disc to be braked; a first piston sealingly slidable in said housing and engaging said first brake pad assembly, said second brake pad assembly being mounted on said housing, and both of said brake pad assemblies being in brake torque transmitting relation to said housing; means preventing rotation of said first piston in said housing and operable to permit rotation of said first piston in said housing and including at least a part of said first brake pad assembly; a second piston sealingly slidable in said first piston and cooperating with said first piston and said housing to define a brake actuating pressure chamber; clutch means acting between said first and second pistons and being normally engaged to resist rotary movement of said second piston relative to said first piston and providing an axial force transmitting connection between said first and second pistons when engaged; an adjuster nut normally in axial force transmitting engagement with said second piston; means axially slidably connecting said adjuster nut and said second piston and preventing relative rotary movement therebetween; shaft means rotatably mounted in said housing and extending axially into said chamber and threadedly engaging said adjuster nut and generating axial movement of said adjuster nut when rotated to actuate the brake through said pistons and said clutch means; means for introducing brake actuating fluid pressure into said chamber to urge said first and second pistons toward the disc to actuate the brake; and a marcelled spring having a first section acting between said first and second pistons and urging said clutch means into engagement with a predetermined preload, and a second section acting between said first piston and said adjuster nut and urging said adjuster nut axially toward axial force transmitting engagement with said second piston; said spring second section acting upon brake release to move said adjuster nut rotationally on said shaft means and thereby imparting axial movement thereto to axially take up any space between said adjuster nut and said second piston caused by brake wear taken up by axial movement of said first and second pistons during brake actuation; said first piston rotation preventing means, when operated to permit rotation of said first piston in said housing, Permitting concurrent rotation of said first and second pistons and said adjuster nut to thread said adjuster nut on said shaft means axially away from the disc to reset said pistons and said adjuster nut for installation of new brake shoe assemblies.