Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Headed fastener element – Having plastically flowable or deflectable end – e.g. – rivet,...
Reexamination Certificate
1999-12-20
2001-06-12
Wilson, Neill (Department: 3627)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Headed fastener element
Having plastically flowable or deflectable end, e.g., rivet,...
C411S179000, C411S360000
Reexamination Certificate
active
06244808
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a punching, stamping rivet including a rivet head, shank, and a groove in the shank.
BACKGROUND OF THE INVENTION
Punching, stamping rivets are used to connect two flat workpieces. The shank of the rivet is hereby pressed (punched) through the workpieces forming two punched holes. The lower workpiece, viewed in punching direction, consists of a plastically deformable material, usually a sheet metal. The shank has a shank groove near the shank end. An annular ring is stamped after the punching operation around the shank end into the lower workpiece by a press tool, thus pressing material of the lower workpiece into the shank groove.
The shank groove has in the case of a known rivet a trapezoidal shape in cross section. When workpieces of a hard material are processed, then there exists the danger that the shank will break in the area of the shank groove. When the upper workpiece consists of a soft material, as, for example, of a soft sheet metal or plastic, then material is sheared off from the upper workpiece by the upper edge of the shank groove and is pressed into the shank groove. The material-receiving space for receiving the material of the lower workpiece is thus reduced and a poor riveted joint is created. When the upper workpiece consists of plastic, then the entire shank groove may be filled with plastic so that a riveted joint is not created. The stamping rivets are manufactured as a turned part, for example on a lathe.
Two factors are, among others, of importance for the strength of the riveted joint. The first factor is that the shank groove is supposed to be filled totally and exclusively with material of the lower workpiece. The second factor is the angle at which the section (surface) of the shank groove, which section is adjacent the shank and, extends. Ideal would be here an approximation to an angle of 90° which, however, would significantly increase the above-mentioned danger of breakage.
SUMMARY OF THE INVENTION
The purpose of this invention is to provide a rivet wherein the strength of the riveted joint is increased without the above-mentioned disadvantages occurring.
This purpose is attained by providing a concave shank groove. The section of the groove adjacent the rivet head extends at an angle less than the angle of the section of the groove adjacent the nonheaded or distal shank end.
The rivet of the present invention can also include a rounded transition from the outer surface of the shank to the groove section adjacent the rivet head. Additionally, the rivet of the present invention can further include a sharp edged transition from the section adjacent the nonheaded shank end to the outer surface of the shank. Moreover, the rivet can include a rounded transition between the two sections of the groove.
In the rivet of the present invention, the section of the groove adjacent the rivet head can extend at an angle of approximately 15° with respect to the shank axis. The section of the groove adjacent the nonheaded shank end is greater than 90°, and preferably about 120°.
REFERENCES:
patent: 3909913 (1975-10-01), Tildesley
patent: 4978270 (1990-12-01), Ackerman
patent: 5678970 (1997-10-01), Caulk
patent: 1 252 615 (1967-10-01), None
patent: 36 40 484 (1988-06-01), None
Stanznieten ist zukunfttrachtig in der Blechverarbeitung by Lothar Budde and Wilhelm Lappe, 1991 (pp. 94-100).
Flynn ,Thiel, Boutell & Tanis, P.C.
Kerb-Konus-Vertriebs-GmbH
Wilson Neill
LandOfFree
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