Patent ID: 6814209
Filing Date: 2004-11-09
Classification: E05F,E05Y,F16H,H02K,Y10T

Abstract:
A clutch mechanism of a motor, the motor having a shaft including a first stop, a worm associated with the shaft, a gear engaged by the worm, and a friction surface near the stop of the shaft, the clutch mechanism comprising:a pressure plate mounted for movement with respect to the shaft toward and away from the friction surface, a spring constructed and arranged to bias the pressure plate towards the friction surface, and a second stop constructed and arranged to limit movement of the pressure plate in a direction away from the friction surface, whereby 1) under a back drive condition of the motor when the motor is not energized and the gear is moved by an externally applied torque causing an axial force to be exerted on the worm inducing an axial and an angular movement to the shaft, the pressure plate is constructed and arranged to move towards and engage the friction surface thereby impeding rotation of the shaft, 2) when the motor is driving in a certain direction, the pressure plate is constructed and arranged to move against the bias of the spring and away from engagement with the friction surface and towards the second stop, and 3) when the motor is driving in a direction opposite the certain direction, the pressure plate is constructed and arranged to engage the first stop, preventing the pressure plate from engaging the friction surface, wherein a portion of the shaft includes a helix and the pressure plate includes a helical configuration that mates with the helix of the shaft.