Patent ID: 9453538
Filing Date: 2016-09-27
CPC Classification: F16D,F16F,Y02T

Claim Text:
1. An isolator for isolating a device driven by an engine via an endless drive member, comprising: a shaft adapter that is connectable with a shaft of the device; a rotary drive member that is engageable with the endless drive member; a torsion spring that is positioned to transfer torque between the shaft adapter and the rotary drive member, wherein the torsion spring has a first helical end, a second helical end and a plurality of coils between the first and second helical ends; and a torque limiting surface that has a selected non-zero spacing from the coils, wherein the spacing between the torque limiting surface and each coil is selected such that, during operation, the torsion spring has a spring rate that is below a first spring rate during relative movement between the shaft adapter and the rotary drive member within a selected angular range that is not less than about 60 degrees from a neutral position, and has a spring rate that increases progressively above the first spring rate during relative movement between the shaft adapter and the rotary drive member beyond the selected angular range from the neutral position.