Worm drive mechanism

A drive mechanism comprising

• an elongated worm;
• a nut having at least one internal groove engaging said worm;
• a sleeve surrounding said nut;
• motor means for rotating said sleeve;
• locking means for locking said nut to said sleeve for rotation therewith, said locking means comprising a recess on the outer surface of said nut, a drive member carried by said sleeve, and a locking spring arranged to bias said drive member toward and into said recess;
• and
• release means for normally preventing longitudinal movement of said nut relative to said sleeve and for releasing said nut for longitudinal movement upon actuation thereof.

A drive mechanism comprising:

• an elongated worm including a flexible steel member wound in the shape of a helix and a flexible restrainer extending internally through said helix, said restrainer member being connected at and intermediate its ends to said wound member;
• an internally threaded plastic nut surrounding said worm and having a threaded internal surface that receives said wound member to produce longitudinal movement of said worm in response to rotational movement of said nut, said nut having a cylindrical outer surface;
• a plurality of rigid telescopically internested members arranged to receive said worm as it moves in a first direction, thereby enabling said worm to resist compressive forces;
• magazine means for receiving and storing said worm in a coiled configuration as it moves in a second direction, said magazine means including a flexible tube;
• a sleeve having a cylindrical inner surface surrounding said nut;
• a yoke on which said sleeve is rotatably mounted;
• motor means for causing rotation of said sleeve;
• clutch means for operatively connecting said motor means to said sleeve and permitting relative rotation between said motor means and said sleeve, said clutch means comprising a first clutch plate secured to said sleeve for rotation therewith and a second clutch plate axially slidable on said sleeve to engage said first clutch plate;
• locking means carried by said sleeve for locking said nut to said sleeve for rotation therewith, said locking means comprising a longitudinal groove defined by the outer surface of said nut, a drive pin carried by said sleeve, and a locking spring arranged to bias said drive pin toward and into said groove, said groove being tapered for maximum depth at the center thereof to allow disengagement of said drive pin from said groove upon longitudinal movement of said nut in either of two opposite directions;
• and
• release means for normally preventing longitudinal movement of said worm without corresponding rotation of said nut and for releasing said worm for free longitudinal movement upon actuation thereof, said release means including a pair of blocking members disposed at opposite ends of said nut, each of said blocking members having a retaining position in which it engages said nut and a release position in which it does not engage said nut, whereby movement of one of said blocking members to its release position permits free longitudinal movement of said nut and said worm member in one direction, said release means further including a pair of springs biasing said blocking members toward said retaining positions.

A drive mechanism comprising:

• an elongated worm;
• a nut having at least one internal groove engaging said worm;
• a sleeve surrounding said nut;
• motor means for rotating said sleeve;
• locking means for locking said nut to said sleeve for rotation therewith, said locking means comprises a recess defined by the outer surface of said nut, a drive member carried by said sleeve, and a locking spring arranged to bias said drive member toward and into said recess, said recess extending longitudinally along said nut and being tapered for maximum depth at the center thereof to allow disengagement of said drive member from said recess upon longitudinal movement of said nut in either of two opposite directions;
• and
• release means for normally preventing longitudinal movement of said nut relative to said sleeve and for releasing said nut for longitudinal movement upon actuation thereof, said release means comprising a pair of blocking members disposed at opposite ends of said nut, each of said blocking members having a retaining position in which it engages said nut and a release position in which it does not engage said nut, whereby movement of one of said blocking members to its release position permits free longitudinal movement of said nut with said worm member in one direction.