Section 4.—BALL-AND-SOCKET JOINTS.
[30]. Universal hinge. The arm can be fixed in any required position by tightening the gland. Useful for stands for articles to be exhibited in any position, telescopes, &c.
[31]. Pipe joint, with similar capabilities.
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[32]. Same as [No. 16], but with screwed gland. If used without the arm, it forms the ordinary ball castor.
[33] & [34]. Dr. Hooke’s universal joint. See application, [No. 292]. See also [Nos. 1359] and [732].
Gas pendants are suspended with a joint similar to [No. 31], but the ball, having only a restricted angular motion, is cut down to a segment only.