| 摘要 |
952,401. Making coils. INDUSTRIAL RESEARCH PRODUCTS Inc. Dec. 27, 1961 [Dec. 27, 1960], No. 46360/61. Headings B3A and B3E. [Also in Division B5] A method of making a self-supporting coil comprises the steps of winding wire on a mandrel and then pulling the mandrel out of the coil by a force acting axially of the coil for a time and with a force sufficient to contract the walls of the mandrel away from the coil to provide an annular clearance throughout the length of the coil tunnel. A plastic mandrel 10 is formed by injection moulding to the shape of blocks 12, 14, connected by a land 16, having a central transverse stratum of slightly less tensile strength than the rest of the land 16. The mandrel may be formed by casting or machining. The block 12 is then clamped between jaws 24, 26, Fig. 5, of a winding machine and wire 17 is wound around the land 16 and an adhesive 28 which does not adhere to the mandrel is applied thereto. The wire coil so formed may then be pressed between flat surfaces and excess adhesive removed. Heavy wire leads 30, 32, Fig. 7, may then be soldered to the ends of the wire of the coil and lie along grooves 38, 40 or holes in the block 14. The mandrel and coil are then mounted in a jig, 37, Fig. 9, and coated with an imbedment compound 41, Fig. 13, which may be the same as the adhesive 28. The adhesive 28 and imbedment compound 41 is cured or set and the coil and mandrel stripped from the jig 37. The block portions 12 and 14 are then clamped in jaws which pull apart so as first to stretch the land 16 of the mandrel and cause it to contract away from the wire windings and then to cause the mandrel to break into two at 54. The mandrel may be of polyethylene, acetyl, acrylic, chlorinated polyether, nylon, polypropylene, styrene, polycarbonate, polychlorotrifluoroethylene, fluorocarbon, vinyl plastic, or polytetrafluoroethylene. |
