| 摘要 |
944,779. Making lock washers; stamping. ILLINOIS TOOL WORKS Inc. June 7, 1962 [Aug. 14, 1961], No. 22104/62. Headings B3A and B3Q. [Also in Division F2] A method of making a lockwasher having an annular body provided with inner and outer margins 24, 26 and a series of twisted radial prongs 28 extending outwards from the margin 26 or inwards from the margin 24, comprises providing a substantially flat sheet material blank having an annular body and a plurality of prongs having roots integrally joined to and spaced circumferentially around a margin of the body, embossing circumferentially adjacent areas of each of the roots generally axially in opposite directions and simultaneously twisting the prongs about their radial axes. Dies 58, 60 for making the lockwashers each comprise a shank having teeth or ribs 64 formed at the circular end. Each of the ribs has a generally triangular cross-section defined by opposite flanks; the angles of inclination of the flank surfaces with respect to a plane perpendicular to the central axis of the shank are unequal.
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