Spring operated, reversibly rotatable body

A spring tensioning and rewinding device which comprises in combination:

• a. a rotatable output shaft that is mounted so that it is reversibly rotatable, and a reversibly rotatable input shaft mounted parallel to said rotatable output shaft,
• b. an elongated flexible member disposed concentrically around said rotatable output shaft so that when said rotatable output shaft is rotated in one direction said flexible member is in a wound condition and when said output shaft is rotated in the opposite direction said flexible member is in an unwound condition,
• c. a spring member mounted on said input shaft, said spring member being arranged to be stretched by the rotation of said output shaft during the unwinding of said elongated flexible member from said output shaft,
• d. means interconnecting said rotatable input shaft with one end of said rotatable output shaft, said means including
• 1. a first conically-shaped body having a base portion and a top mounted on said rotatable output shaft, said first tapered body being drivingly connected to said rotatable output shaft in both directions of rotation,
• 2. a second conically-shaped body having a base portion and a top mounted on said rotatable input shaft, the taper of said second conically-shaped body being disposed opposite to the taper of said first conically-shaped body, and
• 3. a traction wire having one end attached to said base portion of said first conically-shaped body, the other end attached to said base portion of said second conically-shaped body, and the intermediate portion wound around the exterior surfaces of said first and second conically-shaped bodies so that the rotation of the rotatable output shaft in one direction results in winding of the traction wire around said first conically-shaped body and a tensioning of said spring member and so that at some subsequent time said rotatable output shaft can be caused to rotate in the opposite direction by releasing the tension of said spring member, whereby the slope of the genatrix of said tapered bodies is such that the tractive force required to unwind said flexible member from said output shaft will be decreased over the course of said unwinding, and
• 4. a cover enclosing said two-conically shaped bodies, said rotatable output shaft extending from said cover in one direction and said rotatable input shaft extending from said cover in the opposite direction.

An arrangement for reducing the amount of tractive force necessary to extend the strap of an automatically retracting safety belt over the course of the extension of the belt, which arrangement comprises in combination:

• a. a rotatable output shaft that is mounted so that it is reversibly rotatable, and a reversibly rotatable input shaft mounted parallel to said rotatable output shaft,
• b. a belt strap attached to said rotatable output shaft so that when the rotatable output shaft is rotated in one direction said belt strap is in a wound condition and when said rotatable output shaft is rotated in the opposite direction said belt strap is in an unwound condition,
• c. a coil spring member having one end attached to said reversibly rotatable input shaft being arranged to be stretched by the rotation of said rotatable input shaft during the unwinding of said belt strap from said rotatable output shaft, and
• d. means interconnecting said rotatable input shaft with one end of said rotatable output shaft, said means including
• 1. a first tapered body having a base portion and a top mounted on said rotatable output shaft, said first tapered body being drivingly connected to said rotatable output shaft in both directions of rotation,
• 2. a second tapered body having a base portion and a top mounted on said rotatable input shaft, the taper of said second tapered body being disposed opposite to the taper of said first tapered body, and
• 3. a traction wire having one end attached to said base portion of said first tapered body, the other end attached to said base portion of said second tapered body, and the intermediate portion wound around the exterior surfaces of said first and second tapered bodies so that the rotation of the rotatable output shaft in one direction results in winding of the traction wire around said first tapered body and a tensioning of said coil spring member and so that at some subsequent time said rotatable output shaft can be caused to rotate in the opposite direction by releasing the tension of said coil spring member,
• 4. the taper of said first and second bodies being such that the tractive force necessary for extension of the belt is substantially lower at the end of the extension operation than at the beginning.