Clutchless screw drive door operator

DETAILED DESCRIPTION A screw drive operator in accordance with the present invention omits the conventional rear-attachment clutch and hardware associated therewith, and provides a simplified front coupling arrangement that also obviates a front mounted clutch.
The present invention thus greatly simplifies installation of the door operator.
The present invention also overcomes the problem of thrust containment in a front connected screw arrangement.
It also achieves quiet performance while at the same time achieving enhanced security for the enclosed area.
It further achieves significant manufacturing cost reductions by omitting the clutch connection between the motor and the screw.
As opposed to prior, rear mounted clutch arrangements, with the door operator of the present invention, there is no need to fit the motor with a hollow rotor.
The present invention includes a coupling assembly that has a first coupler which connects the rotor to the threaded screw for direct transmission of torque, along the axis of the screw, from the rotor to the threaded screw.
In a preferred embodiment, this first coupler is an integrally-formed polymer element which acts as a universal joint.
The preferred connective element dampens noise to provide for quiet operation.
The coupling means in accordance with the present invention also includes a second coupler.
The second coupler is located on the screw, intermediate the first coupler and the end portion of the guide rail which is nearest the housing that contains the drive motor.
The second coupler is a thrust-absorbing arrangement that is external to the motor.
The second coupler thus obviates need for extensive thrust absorption equipment that in prior commercial systems, was accomplished by bearings or the like in the motor and the mounted clutch assembly.
In a preferred embodiment of the second coupler in accordance with the invention, an unthreaded portion of the screw, which is proximate to the portion of the screw that engages the polymer member of the first coupler, has a circular groove in which is rotatably mounted a stop member that absorbs and thereby contains thrust loads