Patent ID: 8668607

Claim:
A driving pulley for a continuously variable transmission, the driving pulley having a fully clutched mode of operation where a drivebelt and a driveshaft are coupled together in a torque transmitting engagement and having an unclutched mode of operation where there is substantially no torque transmitting engagement between the drivebelt and the driveshaft, the driving pulley being rotatable about a rotation axis and comprising: a first and a second sheave coaxially disposed with reference to the rotation axis, the sheaves having mutually-facing conical walls defining a drivebelt-receiving groove, the drivebelt-receiving groove having a variable width depending on a relative axial distance between the first and the second sheave; an actuation mechanism having one side axially movable within a range of axial positions, the relative axial distance between the two sheaves being selected by moving the side of the actuation mechanism within at least a portion of its axial position range and the driving pulley being set in one among the fully clutched mode of operation and the unclutched mode of operation depending on the axial position of the side of the actuation mechanism; and at least one transitional clutch spring being in a first position when the driving pulley is in the unclutched mode of operation and being in a second position when the driving pulley is in the fully clutched mode of operation, the at least one transitional clutch spring remaining in its second position and substantially in a same compression state regardless of the relative axial distance between the sheaves when the driving pulley is in the fully clutched mode of operation; and wherein when the at least one transitional clutch spring is in the same compression state, the distance between the side of the actuation mechanism and the second sheave remains substantially the same and the actuation mechanism is what moves the second sheave relative to the first sheave.