Bending Products, Inc.

Tools for Bending, Inc.

Samuel B McGuire

Ronald R Stange

Thomas W Woodring

This invention relates to tube bending mandrels and, more particularly, to an improved version thereof characterized by a threaded connection between the tube-shaping ring and the necks of the ball-carrying links that functions in cooperation with an annular stop-forming rib and a retaining ring at opposite ends of the threaded link neck section to resist equally well both tension loads and compression loads while maintaining precise axial spacing between subassemblies in an assembly where, except for the links at opposite extremities, all parts remain fully interchangeable.

Tube bending mandrel

This invention relates to an improved tube bending mandrel of the general type having fixed and bendable sections and wherein the latter comprises a chain of ball and socket elements linked together in end to end relation with each such element being encircled by a ring of the same diameter as the fixed section cooperating therewith and with one another to define limited movable universal connections therebetween. More specifically, the instant invention relates to an improved ball and socket assembly wherein the ball portion comprises two or more spherically-surfaced ring segments which cooperate with each other and with a spherically-concave head formed integral with the body in which the socket is formed on the opposite end of the link to form the ball. The improved mandrel also encompasses dimensioning the socket in the head in relation to the neck of the adjacent socket around which the ball-forming segments are disposed such that the latter can neither be removed nor inserted until the ring surrounding same has been removed and the assembled ring and socket thereabove are tilted to one side and seated within a suitably placed recess. The improved mandrel further includes an expandable ring detent surrounding the ball that temporarily seats with an annular groove in the socket to releasably maintain the elements of the bendable section in axial alignment with one another and with the fixed section.

The present invention pertains to the treatment of a metal surface with a durable low-friction material in such a way as to greatly enhance the lubricant properties of the metal surfaces. The surface coating formed is a chromium plated surface containing microcracks so prepared as to permit injection or insertion of perfluorocarbon compositions such as polytetrafluoroethylene in a fused or nearly-fused state. In the method of forming the surface coating as described, the surface is plated by electrodeposition in a chromic acid bath followed by baking to oxidize the external plated surface. In this way, the surface may then be reverse etched to expand the microcracks without affecting the external surface, following which the plated surface may be heated to, or in excess of, the fusion point of the polytetrafluoroethylene material which is inserted preferably by application to the surface from a solid rod.

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Arvada, CO, United States of America

Samuel B McGuire