Patent ID: 6029735
Filing Date: 2000-02-29
Classification: E06B

Abstract:
A clutch for providing manual operation by a chain of a motor driven device including a main shaft on which the device rotates when the motor driven device is operated on by the motor, wherein the motor is disengagable from the motor driven device by the clutch, and wherein the motor includes a shaft on which the clutch is mounted, comprising:a chain pulley wheel comprising a face and an axis rotationally journalled on the motor shaft for storing the chain that is operable by a user to manually move the motor driven device and which will rotate independently when the user operates the chain so as to engage the clutch so that the motor driven device can be manually moved;a clutch disc having a concentric axis with the chain pulley wheel and concentrically rotationally journalled with the chain pulley wheel on the motor shaft and which is operable to cause the chain to manually drive the motor driven device;a linking element disposed on a periphery of the chain pulley wheel and engaged to the clutch disc for linking the clutch disc to the chain pulley wheel to cause the chain pulley wheel and clutch disc to move rotationally together;a resilient biasing element mounted to the clutch disc and engagable with the linking element for biasing the clutch disc and chain pulley wheel through the linking element into an equilibrium position when the user does not operate the chain to rotate the chain pulley wheel;a driven disc having a concentric axis with the clutch disc and the chain pulley wheel and mounted concentrically between the clutch disc and the chain pulley wheel on the motor shaft in a fixed position to prevent the driven disc from independently rotating on the motor shaft and for translating the rotational motion of the chain pulley wheel to the clutch disc and shaft so as to move the motor driven device when the user manually operates the chain;a drive pawl comprising a pivot point mounted in an off-axis position on the clutch disc and linked at a point on the clutch disc to the chain pulley wheel operable for movement about the pivot point when biased by the chain pulley wheel from a disengaged position wherein the drive pawl does not contact the driven disc to an engaged position wherein the drive pawl engages the driven disc thereby causing the driven disc, clutch disc and chain pulley wheel to rotate together, and wherein when the clutch disc is in the equilibrium position, the pawl adopts its disengaged position and when the user operates the chain, the pawl rotates around its pivot point with respect to the driven disc to move the clutch disc from its equilibrium position by overcoming the resilient biasing means to manually engage the motor driven device.