Shaft mounted overhead door operator, clutch and kit therefor

A clutch for a shaft-mounted overhead door operator, the clutch comprising:

• a collar configured to be attached to a shaft of an overhead door, the collar having a first locking surface;
• a ring having a second locking surface configured to engage with the first locking surface and a motor-engaging surface opposite the second locking surface, wherein when the collar and ring are urged together the collar and ring prevent relative rotation between the collar and ring, wherein the ring is coupled to a motor via the motor-engaging surface, and wherein thereby the motor operates to rotate the shaft to raise or lower the overhead door;
• a passive biasing member configured to exert a first force between the collar and gear to urge the collar and gear away from one another;
• and
• a selectively activatable biasing member configured to exert a second force opposite and greater than the first force, wherein the selectively activatable biasing member releases in response to a power failure or in response to an instruction received from a remote control, wherein the second force is greater than the first force, such that when power is provided to the clutch the clutch transfers torque from the motor to the shaft, and when without power the first force causes the collar and gear to disengage and release the shaft from the motor.

A kit for retrofitting an overhead door operator to a shaft of an overhead door, the kit comprising:

• a motor;
• a gear train coupled to the motor and to a shaft of an overhead door, wherein rotation of the shaft causes the overhead door to raise and lower, and wherein the gear train steps down an operating speed of the motor to raise and lower the door at a speed that is less than four times the operating speed of the motor;
• a clutch attached to an end of the shaft that protrudes laterally from the overhead door, the clutch comprising:
• a first component;
• a second component, wherein at least one of the first and second components are movable between an engaged position and a disengaged position, wherein at least one of the first and second component moves axially along the shaft away from the other component, thereby disengaging the clutch to release the shaft from the gear train;
• a passive biasing component urging the first and second components away from one another toward the second position to disengage the clutch;
• and
• an active biasing component urging the first and second components toward one another toward the first position to engage the clutch, wherein the active biasing component is stronger than the passive biasing component, and wherein if power fails the active biasing component also fails and the passive biasing component is then able to disengage the clutch;
• a controller configured to receive signals to:
• operate the motor to raise, lower, or stop the overhead door;
• activate or deactivate the active biasing component to engage or disengage the clutch;
• wherein the motor, gear train, clutch, and controller are encased in a housing that is approximately three times wider than a diameter of the shaft.