Accession Number : ADD000821

Title :   Coining Friction Rings.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON D C

Personal Author(s) : Gore,L L

Report Date : 19 May 1975

Pagination or Media Count : 9

Abstract : The patent application relates to a structural joint for increasing the fatigue strength characteristics of joined surfaces wherein a coining die is used to produce semi-circular indentations around aligned openings in each of two flat, faying surfaces to be joined. A ring of circular cross-section and the same diameter as the coined indentations is placed therein around the openings and the two surfaces are bolted or riveted together. The coining operation induces a beneficial residual compression stress around the openings and the clamping pressure of the bolt or rivet and ring arrangement causes the load on the joined parts to be transmitted by friction thereby reducing stress due to bearing.

Descriptors :   *Joints, *Fastenings, *Mechanical working, Metalworking, Fatigue(Mechanics), Stress relieving, Tools

Subject Categories : Fabrication Metallurgy
      Couplers, Fasteners, and Joints
      Machinery and Tools

Distribution Statement : APPROVED FOR PUBLIC RELEASE