Patent ID: 7118504
Filing Date: 2006-10-10
Classification: F16H

Abstract:
1. A tensioner for generating tension in a power-transmitting belt as the belt traverses a first sheave and a second sheave, the tensioner comprising: a base; an arm pivotably attached to the base; a pulley rotatably attached to the arm for engaging the belt; a spring operatively connected to the arm and the base for urging the arm to pivot relative to the base in a first direction, thereby urging the pulley into engagement with the belt with a force to tension the belt; and an asymmetric fluid damper comprising a fluid containing chamber located between the base and the arm, the chamber moving with the arm relative to the base, and a valve pivotably attached to the base and pivotable between an open position and a closed position, the valve pivoting to the open position when the arm moves in the first direction and pivoting to the closed position when the arm moves in a second direction, the valve positioned in the fluid containing chamber to restrict fluid flow when in the closed position, thereby resisting movement of the arm in the second direction; wherein the valve is biased toward the closed position; and further comprising a solenoid having a plunger movable between a retracted position and an extended position, the plunger engaging the valve to lock the valve in the closed position when in the extended position, thereby resisting movement of the arm in the first and second directions.