| 摘要 |
A connective joint comprises the following seven elements: (a) Four quarter spheres arranged in adjacent quadrant relationship to form a substantially spherical element or "ball". The quarter spheres are provided with grooved edges that form two substantially perpendicular grooves extending around the spherical element; (b) Two hinge elements, each having a ring shaped portion that is inserted in an individual one of the two grooves; (c) A device for applying a force between two diametrically opposing ones of the quarter spheres in the spherical element. |
