| 摘要 |
758,478. Screw-sockets. HELI-COIL CORPORATION. June 23, 1954 [July 16, 1953; June 8, 1954], No. 18373(54. Class 89 (1). [Also in Groups XXII and XXIII] A wire-coil, screw-thread insert comprises a cylindrical body 10, Fig. 1, of wire helicallywound about the cylinder axis, the wire at the leading end 15 of the insert being bent to form a grip-end of polygonal form surrounding the body-axis a through more than 180 degrees, to receive a correspondingly shaped tool-shank t whereby the insert is turned and contracted, during insertion in a threaded hole. The end may be triangular,. comprising sides 16 ... 18, Fig. 2, the corners 20, 21 being located on a helix in continuation of the helix of the body, and on diameters smaller than the rootdiameter of the threaded-hole but larger than the crest-diameter thereof. After insertion, the tool is turned in the opposite direction to expand the grip-end as shown in Fig. 3, the sides 16 ... 18 being slightly curved to lock an inserted screw. The grip-end may be square, rectangular or pentagonal comprising arcuate sides 60 ... 63, Fig. 9, and a straight end 64. In a modification, end 64 and part of side 63 are omitted. At least two angles of the polygon are less than 90 degrees. |
