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Section for the manufacture of hollow body elements, hollow body element and component assembly

Section for the manufacture of hollow body elements, hollow body element and component assembly description/claims

The present invention relates to a section for the manufacture of hollow body elements, in particular for the manufacture of pierce and rivet nuts having a square or rectangular outline in plan view which are to be provided in a later process with a ring-like piercing section at a side confronting a component consisting of a sheet metal material or the like. Furthermore, the invention relates to hollow body elements which are manufactured from portions of the section and also to component assemblies which result from attachment of the hollow body elements to components.

Methods for the manufacture of hollow body elements, such as nut elements, for the attachment to components normally consisting of sheet metal are known. In such known methods the hollow body elements are provided with an at least substantially square or rectangular outline by cutting off individual lengths of the section, which is present in the form of a bar section or of a coil alter the previous punching of respective apertures in the section, optionally with the subsequent formation of a thread cylinder.

A method of the initially named kind and also the corresponding hollow body elements are for example known from U.S. Pat. No. 4,971,499. Hollow body elements are also sold by the Company Profil Verbindungstechnik GmbH & Co. KG in Germany under the designation HI rectangular nuts.

The object of the present invention is to provide a section from which hollow body elements, in particular rectangular nut elements can be produced with favourably priced manufacture, with the hollow body elements having improved mechanical characteristics in comparison to known elements and after attachment to a component of sheet metal, for example a higher pull-out resistance and an improved security against rotation. Moreover, such hollow body elements should show a reduced notching action so that the fatigue characteristics of component assemblies comprising a component normally consisting of sheet metal and hollow body elements attached to the latter are also improved under dynamic loads.

In order to satisfy this object a section of the initially named kind is provided which is characterised in that, the section is at least substantially rectangular in cross-section with two bars at the side later confronting the component which are spaced apart and extend parallel to the longitudinal sides of the section, are likewise at least substantially rectangular in cross-section and form, in the finished element a feature providing security against rotation and in that the bars respectively have an inclined flank at the inner side which forms an undercut.

The ring-like piercing section which lies at the centre of the element can be circular, oval or polygonal. In all these forms the notch action is significantly reduced relative to a rectangular piercing section as in the prior art. Through the undercuts in the region of the bars an excellent press-out resistance and a high security against rotation are achieved.

The manufacture from a section, which is present either in the form of a bar section or in the form of a coil in which the section already has the basic shape of the element, makes it possible to dispense with comparatively costly cold heading machines and permits instead of this the manufacture of the elements in a normal punching press which is equipped with progressive tooling for carrying out the individual manufacturing steps. The manufacture in a punching press utilizing progressive tooling is particularly cost favourable in comparison to the use of cold heading machines. Manufacture on a transfer press is also possible under the same conditions. In this arrangement the separating process must be displaced into the first stage.

Particularly favourable sections for manufacturing hollow body elements result from sections which are able to be manufactured by cold rolling, for example from a 35B2 steel material. Particular sections of the invention lead, on the one hand, to elements which are favourable weight-wise and, on the other hand, also to elements which can be manufactured at favourable cost and to elements which have excellent mechanical characteristics.

With a hollow body element for the attachment to a component, in particular to a component consisting of sheet metal, in which the hollow body element has bars at two opposite sides extending parallel to one another which form a security against rotation with the component and a centrally arranged punched aperture extending perpendicular to the component side, the punched aperture optionally having a thread cylinder, the invention provides that a ring-like projection is present at the side of the hollow body element that faces the component and concentric to the punched aperture, the ring-like projection being formed as a piercing section and that a recessed region is present between the bars and the ring-like piercing section, with bars only being present at two opposite sides of the hollow body element and having an inclined flank at the side facing the ring-like piercing section which forms an undercut.

Since a ring-like piercing section is present a ring-like slug is punched out of the component during the attachment of the hollow body element so that a notch effect in the region of the circular aperture produced in the component need no longer be feared. That is to say the rectangular edges present in the known elements, which arose as result of the previous rectangular piercing section are, so to say, omitted. In this connection it is noted that in the prior art the rectangular piercing section is defined by the cross-section of the section that is used, whereas in the present invention one makes use of the special piercing section which is produced in accordance with the invention by an upsetting process.

Particularly favourable variants of the hollow body element result from the claims 6 to 14.

Further advantages of the section of the invention, of the hollow body element of the invention and of the component assemblies in accordance with the invention are to be found in the following description of preferred examples which are explained further with reference to the drawings. In the drawings are shown:

FIG. 1 a perspective representation of a section of a first section in accordance with the invention for the manufacture of hollow body elements,

FIGS. 2A-F a series of drawings which show the individual method steps which are required in order to manufacture a hollow body element in accordance with the invention from the section of FIG. 1,

FIG. 3 a partly sectioned drawing to explain the carrying out of the upsetting process in accordance with FIG. 2B in a station of progressive tooling in a punching press,

FIGS. 4A-F a series of drawings to set forth the precise shape of the hollow body element in accordance with the invention manufactured from the section of FIG. 1,

FIG. 5 a partly sectioned representation of a component assembly comprising a sheet metal part and a hollow body element in accordance with the invention attached thereto, the hollow body element being in accordance with FIG. 4,

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• Utility Patent

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