Tensioner having protrusion-preventing mechanism for a plunger
First Claim
1. A tensioner comprising a housing, a plunger protruding from the housing, the plunger being movable between a retracted position and a protruding condition and biased in the protruding direction, and a locking member, wherein said locking member comprises a wire spring comprising a locking portion engageable with said plunger when said plunger is in said retracted position for temporarily maintaining said plunger in said retracted position, and two arms extending from said locking portion, the respective arms having front ends pivotally attached to said housing whereby said wire spring is pivotable on the housing from a position in which said locking portion is engaged with the plunger to a position in which said locking portion is disengaged from said plunger, said front ends of the arms being pivoted on axes laterally displaced with respect to each other in a direction such that a stress is generated in said wire spring when the locking portion thereof is engaged with the plunger, said stress resiliently urging the wire spring in a direction to disengage said locking portion from said plunger.
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Accused Products
Abstract
In a tensioner for a timing belt or chain in an engine, a plunger, which is spring-biased in a protruding direction, is temporarily held in a retracted condition by a pivoted U-shaped or L-shaped wire spring. The spring has a locking portion engageable with a pin or groove on the plunger, and two arms having ends remote from the locking portion. The ends are pivoted to the housing on laterally displaced pivot axes. The lateral displacement of the pivot axes causes the wire spring to be under stress when its locking portion is engaged with the plunger, and the stress urges the locking portion toward a disengaged position. Thus, the plunger is held in its retracted condition during assembly by the locking portion of the wire spring, but is automatically released by disengagement of the locking portion from the plunger when the plunger is moved farther in the retracting direction.
15 Citations
15 Claims
- 1. A tensioner comprising a housing, a plunger protruding from the housing, the plunger being movable between a retracted position and a protruding condition and biased in the protruding direction, and a locking member, wherein said locking member comprises a wire spring comprising a locking portion engageable with said plunger when said plunger is in said retracted position for temporarily maintaining said plunger in said retracted position, and two arms extending from said locking portion, the respective arms having front ends pivotally attached to said housing whereby said wire spring is pivotable on the housing from a position in which said locking portion is engaged with the plunger to a position in which said locking portion is disengaged from said plunger, said front ends of the arms being pivoted on axes laterally displaced with respect to each other in a direction such that a stress is generated in said wire spring when the locking portion thereof is engaged with the plunger, said stress resiliently urging the wire spring in a direction to disengage said locking portion from said plunger.
Specification