Rotary joint assembly and combination clip-hook and jewelry piece employing the same

A closable assembly comprising:

• a first portion and a second portion, each of the first portion and the second portion being rotatably joined at a rotary joint at respective joint ends thereof, the first portion and the second portion each defining a perimeter shape wherein the first portion and the second portion define (a) an enclosed orientation when the joint is in a first rotational position with respective free ends of the first portion and the second portion in a confronting relationship and (b) an opened orientation when the joint is in a second rotational position rotationally remote from the first rotational position, the second rotational position defining a hook shape;
• and
• wherein the joint that allows the first portion and the second portion to be rotated between first rotational position and the second rotational position with movement therebetween by application of predetermined rotational torque at the joint, and wherein the first portion is movably locked in each of the first portion and the second portion upon application of torque less than the predetermined rotational torque, and
• wherein the joint includes an index assembly having a first index surface on the first portion having at least one male projection and a second index surface on the second portion having at least one female detent, each of the first index surface and the second index surface being rotatably positioned on an axis and a spring assembly that movably biases the first index surface toward the second index surface, and allows movement of the first index surface away from the second index surface under compression of the spring assembly, and
• wherein, in the enclosed orientation, the first portion and the second portion define a jewelry piece and wherein the first portion and the second portion enable removal of the jewelry piece in the opened orientation.