Power assist module for roller shades

摘要

A power assist module for use in roller tube driven products, such as roller shades. The module may be pre-wound prior to installation in a roller tube and retains its pre-wound condition, even after use, when removed from the roller tube.

主权项

1. A power assist arrangement for a covering for an architectural opening, comprising:
at least one independent power assist module for mounting inside a rotator tube to assist with the rotation of the rotator tube, said independent power assist module including the following prior to being mounted inside the rotator tube:
an elongated spring shaft having first and second ends;a drive plug mounted adjacent to one of said first and second ends of said spring shaft for rotation relative to said spring shaft such that said drive plug will rotate with the rotator tube when the power assist module is mounted inside the rotator tube;an elongated spring mounted over said spring shaft, said elongated spring having a first end fixed relative to said spring shaft and a second end fixed relative to said drive plug; anda prewinding mechanism for prewinding said spring relative to said spring shaft, including a threaded follower member mounted for rotation about an axis of rotation relative to said spring shaft; a threaded shaft member non-rotatably mounted relative to said spring shaft and threaded to said follower member; a first abutment surface on said threaded shaft member and a second abutment surface on said threaded follower member, said first and second abutment surfaces being located so as to abut each other and prevent relative rotation between said threaded shaft member and said threaded follower member when said threaded follower member has threaded a desired axial distance in a first direction relative to said threaded shaft member; wherein the at least one independent power assist module has a pre-wound condition and is configured to maintain said pre-wound condition when removed from the rotator tube.