A tensioner comprising a base, an arm engaged with the base for oscillatory movement, a torsion spring engaged with the base and the arm, the torsion spring exerting a force on the arm, a damping mechanism exerting a frictional damping force between the base and the arm for damping an arm oscillation, the damping mechanism comprising a Belleville spring, the frictional damping force instantaneously adjustable by changing a Belleville spring force.
1. A tensioner comprising:
a base;
an arm engaged with the base for oscillatory movement;
a torsion spring engaged with the base and the arm, the torsion spring exerting a force on the arm;
a damping mechanism exerting a frictional damping force between the base and the arm for damping an arm oscillation, the damping mechanism comprising a Belleville spring;
the damping mechanism comprises a damping adjuster threadably engaged with the arm;
the frictional damping force instantaneously adjustable by rotating the damping adjuster in relation to the base and the arm thereby changing a Belleville spring force.
2. The tensioner as in claim 1 , wherein:
the damping mechanism comprises a radially extending planar member fixedly connected to the base; and
a damping member is disposed between the Belleville spring and the radially extending planar member.
3. The tensioner as in claim 2 , wherein the damping mechanism comprises a damping adjuster threadably engaged with the arm.
4. The tensioner as in claim 1 , wherein the base comprises a pin for determining an installation position.
5. The tensioner as in claim 1 further comprising two or more Belleville springs.