| 摘要 |
1390480 Riveting MCDONNELL DOUGLAS CORP 11 Sept 1973 [25 Sept 1972] 42599/73 Heading B3U [Also in Division F2] The head 12 of'a rivet 10 has a frusto-conical undersurface 20 flared uniformly outwardly from the shank 14 to the periphery 26 of an upper surface 22 shaped as a minor portion of a filled torus, with a planar central portion 23 having a diameter C at least one fourth of the head diameter B, and a convexly curved peripheral annulus 24. The head diameter C is less than the maximum diameter D of a countersink 32 in a workpiece 16 so that the outer periphery of the head lies below the workpiece surface 34. The planar surface 23 lies at least 0À002 inch above the surface 34. When the rivet is set, plastic flow of the head material axially inwardly and radially outwardly leaves the major portion of the rivet head upper surface substantially flush, e.g. 0.000 to 0À003 inch above, with the surface 34, dipping at the periphery to a margin (42) (Fig. 2, not shown), slightly below the surface 34. The width and depth of the small annular indentation (42) at the periphery of the rivet head can be measured after setting, to check that the rivet was installed to production tolerances. The planar surface 23 of the rivet head preferably has the same diameter C as the flat leading surface 38 of the rivet shank 14. |
