Cup nut mass production process
OwnerHeinz W. Erdmanninventor
Life of this patent
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Abstract
The present process is especially suitable for economically producing cup nuts in large quantities by conventionally manufacturing the nuts and by deep drawing the cups separately from sheet metal in a single step to provide the cup with an outwardly facing chamfer along its edge surrounding the open end of the cup. In other words, the chamfer is produced as the result of the deep drawing step. The cup and the nut are connected by applying pressure and welding current whereby the pressure is applied just prior to, during and shortly after the welding to produce an intimate bond between the nut and cup. Due to the chamfer the welding bond forms an inwardly facing butt welding seam preferably running all around the edge of the cup, whereby a machining after the welding is avoided.
Claims7
In a mass production process for welding metal parts of a cup nut together by means of resistance welding whereby the metal parts are pressed together briefly prior, during and briefly after the application of welding current, the improvement comprising deep drawing from sheet metal in a single step a cup which has a dome and an edge around its open end providing said edge of the cup in said single deep drawing step with an outwardly facing chamfer having an inwardly rising circular ridge, then substantially axially aligning said cup with a standard nut so that the inwardly rising circular ridge of the chamfer contacts a nut face, axially pressing the nut and cup together, applying welding current while maintaining said pressing, and removing said axial pressure briefly after the termination of the welding current whereby the material of the cup adjacent to said chamfer is used to form an inwardly facing one sided butt welding seam without a visible welding seam at the juncture of the nut and the outer edge of the cup and thus a machining of the welding seam is obviated.
Dependencies are inferred from the claim text.