A tensioner comprising a base, a first pivot arm pivotally engaged to the base, a first pulley journalled to the first pivot arm, a second pivot arm pivotally engaged to the base, a second pulley journalled to the second pivot arm, a flexible tensile member having a toothed engagement with the first pivot arm and a toothed engagement with the second pivot arm whereby the first pivot arm and the second pivot arm move in a coordinated manner, and a tensioner assembly pivotally engaged to the base and engaged with the flexible tensile member.
1. A tensioner comprising:
a base;
a first pivot arm pivotally engaged to the base, a first pulley journalled to the first pivot arm;
a second pivot arm pivotally engaged to the base, a second pulley journalled to the second pivot arm;
a flexible tensile member having a toothed engagement with the first pivot arm and a toothed engagement with the second pivot arm whereby the first pivot arm and the second pivot arm move in a coordinated manner; and
a tensioner assembly pivotally engaged to the base and engaged with the flexible tensile member.
2. The tensioner as in claim 1 further comprising:
a first damping assembly frictionally engaged with the first pivot arm, the first damping assembly exerting a greater damping force on the first pivot arm in a first direction than a second direction; and
a second damping assembly frictionally engaged with the second pivot arm, the second damping assembly exerting a greater damping force on the second pivot arm in a first direction than a second direction.
3. The tensioner as in claim 2 , wherein:
the first damping assembly comprises a first clutch spring engaged with the base, the first clutch spring loaded in an unwinding direction; and
the second damping assembly comprises a second clutch spring engaged with the base, the second clutch spring loaded in an unwinding direction.
4. The tensioner as in claim 3 , wherein the first clutch spring is wound in a direction opposite that of the second clutch spring.
5. The tensioner as in claim 4 , wherein the tensioner assembly comprises a torsion spring.
6. The tensioner as in claim 1 , wherein:
the first pivot arm comprises a bore for receiving a fastener; and
the second pivot arm comprises a bore for receiving a fastener.
7. The tensioner as in claim 1 , wherein the flexible tensile member comprises a toothed belt.
8. The tensioner as in claim 4 , wherein the first damping assembly comprises a first damping shoe disposed radially inward of a first damping ring, the first damping shoe engagable with the first clutch spring, the first damping ring engaged with the first pivot arm.
9. The tensioner as in claim 4 , wherein the second damping assembly comprises a second damping shoe disposed radially inward of a second damping ring, the second damping shoe engagable with the second clutch spring, the second damping ring engaged with the second pivot arm.
10. The tensioner as in claim 1 mounted to an alternator.