Parking brake actuator for disc brakes

Claim 2

In a disc brake: a rotor having a pair of friction faces; a torque member; a pair of friction elements, one of said elements being disposed adjacent each of said friction faces; a caliper slidably mounted on said torque member and operatively connected to each of said friction elements for urging the latter into braking engagement with their corresponding friction faces; said caliper including a housing defining a bore therewithin; fluid motor means including a piston slidable in said bore for effecting a service actuation of said brake; and mechanical actuating means for effecting a parking actuation of said brake; said mechanical actuating means including a plunger slidably mounted in said bore, a lever movably mounted in said bore and extending from said housing, and a toggle link interconnecting said lever and said plunger to slide said plunger toward the rotor as the lever is moved; and means closing one end of said bore defining an opening, said lever extending through the opening defined by the closing means and having a circumferentially extending, radially projecting camming surface cooperating with the circumferential wall of the opening to permit rocking movement of the lever with respect to the housing.

Claim 3

In a disc brake: a rotor having a pair of friction faces; a torque member; a pair of friction elements, one of said elements being disposed adjacent each of said friction faces; a caliper slidably mounted on said torque member and operatively connected to each of said friction elements for urging the latter into braking engagement with their corresponding friction faces; said caliper including a housing defining a bore therewithin; fluid motor means including a piston slidable in said bore for effecting a service actuation of said brake; and mechanical actuating means for effecting a parking actuation of said brake; said mechanical actuating means including a plunger slidably mounted in said bore, first pivot means rigidly secured to said housing and extending across said bore, a lever rotatable about said pivot means for movement relative to said housing, a toggle link having a pair of opposed ends, second pivot means connecting one of said opposed ends of said toggle link to said lever, third pivot means connecting the other of said opposed ends of said toggle link to said plunger, said lever pivoting about said first pivot means from a first position in which the edge of the lever engages the wall of the bore to a second position in which the edge of the lever is disposed away from the wall of the bore, the pivoting movement os said lever being transmitted to said plunger by said toggle link to effect a parking actuation; said second pivot means including a recess in the end of said lever, said one opposed end of said toggle link having a radiused surface engaging said recess, the radius of said radiused surface being substantially less than the distance between said first pivot means and said recess to provide a substantiallY ''''knife-edge'''' engagement between the one opposed end and the recess, whereby the friction force generated by engagement of the one opposed end with the recess acts through a relatively short lever arm to produce a relatively low-frictional torque and the actuating force acts through a substantially larger lever arm to provide a relatively high actuating torque.

Claim 4

In a disc brake: a rotor having a pair of friction faces; a torque member; a pair of friction elements, one of said elements being disposed adjacent each of said friction faces; a caliper slidably mounted on said torque member and operatively connected to each of said friction elements for urging the latter into braking engagement with their corresponding friction faces; said caliper including a housing defining a bore therewithin; fluid motor means including a piston slidable in said bore for effecting a service actuation of said brake; and mechanical actuating means for effecting a parking actuation of said brake; said mechanical actuating means including a plunger slidably mounted in said bore, first pivot means rigidly secured to said housing and extending across said bore, a lever rotatable about said pivot means for movement relative to said housing, a toggle link having a pair of opposed ends, second pivot means connecting one of said opposed ends of said toggle link to said lever, third pivot means connecting the other of said opposed ends of said toggle link to said plunger, said lever pivoting about said first pivot means from a first position in which the edge of the lever engages the wall of the bore to a second position in which the edge of the lever is disposed away from the wall of the bore, the pivoting movement os said lever being transmitted to said plunger by said toggle link to effect a parking actuation; said second pivot means including a recess in the end of said lever, said one opposed end of said toggle link having a radiused surface engaging said recess, the radius of said radiused surface being substantially less than the distance between said first pivot means and said recess to provide a substantiallY ''''knife-edge'''' engagement between the one opposed end and the recess, whereby the friction force generated by engagement of the one opposed end with the recess acts through a relatively short lever arm to produce a relatively low-frictional torque and the actuating force acts through a substantially larger lever arm to provide a relatively high actuating torque.

Claim 5

In a disc brake: a rotor having a pair of friction faces; a torque member; a pair of friction elements, one of said elements being disposed adjacent each of said friction faces; a caliper slidably mounted on said torque member and operatively connected to each of said friction elements for urging the latter into braking engagement with their corresponding friction faces; said caliper including a housing defining a bore therewithin; fluid motor means including a piston slidable in said bore for effecting a service actuation of said brake; and mechanical actuating means for effecting a parking actuation of said brake; said mechanical actuating means including a plunger slidably mounted in said bore, first pivot means rigidly secured to said housing and extending across said bore, a lever rotatable about said pivot means for movement relative to said housing, a toggle link having a pair of opposed ends, second pivot means connecting one of said opposed ends of said toggle link to said lever, third pivot means connecting the other of said opposed ends of said toggle link to said plunger, said lever pivoting about said first pivot means from a first position in which the edge of the lever engages the wall of the bore to a second position in which the edge of the lever is disposed away from the wall of the bore, the pivoting movement of said lever being transmitted to said plunger by said toggle link to effect a parking actuation; said second pivot means including a recess in the end of said lever, said one opposed end of said toggle link having a radiused surface engaging said recess, the radius of said radiused surface being substantially less than the length of the toggle link between said opposed ends to provide a substantially ''''knife-edge'''' engagement between the one opposed end and the recess, whereby the friction force generated by engagement of the one opposed end with the recess acts through a relatively short lever arm to produce a relatively low-frictional torque and the actuating force acts through a substantially larger lever arm to provide a relatively high actuating torque.

Claim 6

In a disc brake: a rotor having a pair of friction faces; a torque member; a pair of friction elements, one of said elements being disposed adjacent each of said friction faces; a caliper slidably mounted on said torque member and operatively connected to each of said friction elements for urging the latter into braking engagement with their corresponding friction faces; said caliper including a housing defining a bore therewithin; fluid motor means including a piston slidable in said bore for effecting a service actuation of said brake; and mechanical actuating means for effecting a parking actuation of said brake; said mechanical actuating means including a plunger slidably mounted in said bore, first pivot means rigidly secured to said housing and extending across said bore, a lever rotatable about said pivot means for movement relative to said housing, a toggle link having a pair of opposed ends, second pivot means connecting one of said opposed ends of said toggle link to said lever, third pivot means connecting the other of said opposed ends of said toggle link to said plunger, said lever pivoting about said first pivot means from a first position in which the edge of the lever engages the wall of the bore to a second position in which the edge of the lever is disposed away from the wall of the bore, the pivoting movement of said lever being transmitted to said plunger by said toggle link to effect a parking actuation; said second pivot means including a recess in the end of said lever, said one opposed end of said toggle link having a radiused surface engaging said recess, the radius of said radiused surface being substantially less than the length of the toggle link between said opposed ends to provide a substantially ''''knife-edge'''' engagement between the one opposed end and the recess, whereby the friction force generated by engagement of the one opposed end with the recess acts through a relatively short lever arm to produce a relatively low-frictional torque and the actuating force acts through a substantially larger lever arm to provide a relatively high actuating torque.

Claim 7

The invention of claim 3: said third pivot means including a recess in said plunger, said other opposed end of said toggle link having a radiused surface engaging said recess, the radius of said radiused surface being substantially less than the length of the toggle link between said opposed ends.