The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 20, 1988
Filed:
Oct. 29, 1986
Eugene R Speakman, Fullerton, CA (US);
McDonnell Douglas Corporation, Long Beach, CA (US);
Abstract
A stress coining tool for fatigue life extension of the wall of an aperture in a metallic structural member, in the form of a rigid elongated member having a plurality of annular olive-like protuberances of a progressively larger diameter from one end of the member, and an additional olive-like protuberance of a smaller diameter than the largest protuberance, such additional protuberance located on the opposite side of the largest protuberance from the other protuberances. The diameter of the largest annular protuberance is such that the material forming the wall of the aperture is displaced radially elastically and plastically an amount to provide stress coining and to minimize stress concentration in the wall of the aperture. The additional olive-like protuberance to the rear of the largest protuberance is of a diameter such that the latter protuberance functions as a guide to permit passage of the tool back through the aperture without causing any further plastic deformation of the wall of the aperture. The elongated member is provided with a serrated pole stem which permits attachment of the tool to a rivet gun in conjunction with a mechanism thereon for rapid force vibration of the tool to impact it through the aperture, and then to impact it back through the aperture.