Release mechanism for a parking brake clutch
A parking brake assembly which includes a brake lever, a rotary clutch and a lock-release mechanism which cooperate to selectively lock and release a parking brake. The clutch allows actuation of the brake lever in one direction and prevents movement of the brake lever in an opposite direction. The lock-release mechanism allows selective movement of the rotary clutch and the brake lever together in the opposite direction. A gear mechanism is operatively coupled between the brake lever and the rotary clutch.
1. A parking brake assembly for a motor vehicle, said parking brake assembly comprising:
a brake lever having a sector;
a pivot sleeve coupled to the brake lever and having gear teeth formed on an end of the pivot sleeve that are in mesh with the sector;
a roller clutch having a roller support operatively connected to the pivot sleeve by a roller disposed between the pivot sleeve and a bearing surface of the roller support and the roller clutch preventing movement of the pivot sleeve relative to the roller support in a first direction and the roller support movable in a direction opposite the first direction when a lock-release mechanism is moved to an unlocked position; and
wherein the lock-release mechanism releasably fixes movement of the roller support using a force that is non-normal to a torque load applied to the roller clutch.
2. The parking brake assembly of claim 1 , wherein the lock-release mechanism includes one or more notches formed in the roller support for receiving a movable block.
3. The parking brake assembly of claim 2 , wherein the lock-release mechanism includes a ring having a bearing surface for maintaining the block in the notch and a recess formed in the bearing surface for receiving at least a portion of the block while disengaged from the notch.
4. The parking brake assembly as set forth in claim 3 , wherein the ring is selectively movable between a locked position, in which the bearing surface retains the block in the notch of the roller support, and the unlocked position, in which the recess is generally aligned with the notch to allow movement of the block between the notch and the recess such that the block is not in the notch when the ring is in the unlocked position and the roller support is rotating.
5. A parking brake assembly for a motor vehicle, said parking brake assembly comprising:
a brake lever connected to a sector;
a roller clutch including at least one roller, the roller clutch intermeshed with the sector of the brake lever and allowing pivotal movement of the brake lever in a first direction and preventing pivotal movement of the brake lever in an opposite second direction, the roller clutch being supported by a roller support that is movable together with the roller clutch in the first direction when a lock-release mechanism is moved to an unlocked position; and
the lock-release mechanism including a block movable between a locked position to prevent movement of the roller support in the first direction and the unlocked position to allow movement of the roller support in the first direction, the roller support including one or more notches formed thereon;
wherein the lock-release mechanism includes a ring having a bearing surface maintaining the block in the notch and a recess formed in the bearing surface receiving the block while disengaged from the notch such that the block is not in the one or more notches when disengaged.
6. A parking brake assembly for a motor vehicle, said parking brake assembly comprising:
a brake lever pivotally coupled to a fixed support for rotation about a first pivot;
a member to be controlled pivotally coupled to the fixed support for movement about a second pivot spaced apart from the first pivot;
a roller clutch having a roller support supporting the member to be controlled, the roller clutch having at least one roller disposed between the roller support and the member to be controlled allowing movement in a first direction of the member to be controlled relative to the roller support, the roller support being movable relative to the fixed support for movement of the roller support and the member to be controlled together in a direction opposite the first direction, the roller support including a notch;
a lock-release mechanism having a block including a circumferential bearing surface, the block selectively movable between a locked position operatively engaging the fixed support and roller support to prevent rotation of the roller support relative to the fixed support, wherein at least a portion of the block is positioned in the notch and wherein the notch engages the circumferential bearing surface to lock the roller support with respect to the fixed support and an unlocked position disengaged from the roller support to allow rotation of the roller support and member to be controlled together in the direction opposite the first direction;
a gear mechanism operative between the member to be controlled and the brake lever, the gear mechanism having a pinion coupled to one of the member to be controlled and the brake lever and a sector coupled to the other of the one of the member to be controlled and the brake lever, the pinion and the sector being mechanically engaged for transferring movement between the member to be controlled and the brake lever; and
an adjuster movably coupled to the fixed support and actuating the block between engagement and disengagement with the notch in response to the movement of the adjuster relative to the fixed support.
7. The parking brake assembly as set forth in claim 6 , wherein the adjuster includes a bearing surface that contacts the circumferential bearing surface and maintains the block in the notch of the roller support.
8. The parking brake assembly as set forth in claim 7 , wherein the bearing surface of the adjuster contacts the circumferential bearing surface of the block with a force that is non-normal to a torque load applied to the member to be controlled.
9. The parking brake assembly as set forth in claim 7 , wherein the adjuster includes a recess formed along the bearing surface of the adjuster, the recess receiving at least a portion of the block therein while the block is disengaged from the notches in the roller support.
10. The parking brake assembly as set forth in claim 9 including a guide member fixed in relation to the fixed support, the guide member having a slot allowing movement of the block therethrough between the notch in the roller support and the recess.
11. The parking brake assembly as set forth in claim 9 , wherein the guide member is disposed between the roller support and the adjuster and the slot in the guide member allows generally radial movement of the block between the notch and the recess.
12. The parking brake assembly as set forth in claim 9 , wherein the adjuster is a ring rotatably coupled to the fixed support for movement between the locked position, wherein the recess is rotatably spaced apart from the block and the bearing surface is engaged with the circumferential bearing surface to retain the block in the notch of the roller support, and the unlocked position, wherein the recess is generally rotatably aligned with the notch to allow movement of the block between the notch and the recess.
13. The parking brake assembly as set forth in claim 12 including a biasing member for biasing the ring toward the locked position.
14. The parking brake assembly as set forth in claim 12 including a powered actuator for actuating the adjuster between the locked and unlocked positions.
15. The parking brake assembly as set forth in claim 6 , wherein the block is selected from the group consisting of: a cylindrically shaped pin, and a ball.