The present invention is a torque producing apparatus comprising a first member, a second member, and a retention means. The first member has first and second arms, each having first and second ends, and a connection portion adjacent the joined first ends of the first and second arms. The arms have an outer surface and define an axial aperture. The axial aperture defines at least a portion of an inner surface of the arms. The second ends of the arms define an opening between the outer and inner surfaces. At least one of the inner and outer surfaces have a predetermined diameter when the member is in a relaxed state. The second member has a surface arranged to engage in interference fit against at least one surface of the first member when the first member is in its relaxed state. The retention means engages the connection portion of the first member so that the second member rotates relative to the first member upon relative rotation of the second member and the retention means.
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