Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
1998-12-17
2001-08-21
Wilson, Neill (Department: 3627)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S521000, C029S522100, C029S798000, C411S179000, C411S180000
Reexamination Certificate
active
06276040
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an element, for example a fastening element such as a hollow nut element or a bolt element in particular a nut element, for attachment to a plate-like component, wherein an annular or ring-shaped recess or groove is present at an end face of the element facing the component within a raised annular or ring-shaped contact surface, wherein at least one undercut is preferably provided in a side wall of the recess, and also features providing security against rotation are provided and wherein a cylindrical punch or pilot section concentric to the central longitudinal axis of the element projects at the said end face within the ring-shaped recess and the outer boundary wall of the cylindrical punch section has a preferably ring-shaped or annular undercut. In addition, the present invention relates to a method of attaching such an element to a plate-like component, to a component assembly and to a die button for use in the method for attaching the element to a plate-like component.
BACKGROUND OF THE INVENTION
An element of this type is known from U.S. Pat. No. 3,648,747, and also from the U.S. Pat. Nos. 5,340,251, 3,234,987 and 3,253,631.
Further elements of this type are known from the European patent application with the publication number EP-A-0 553 822 or the corresponding U.S. No. 5,340,251 and also from the European application with the publication number EP-A-0 669 473.
A similar element is also known from the European application with the publication number EP-A0 663 247; however, this application is concerned with the manufacturing of an element of this kind rather than with the element itself.
Such elements are generally formed as elements with hollow bodies, or more precisely as nut elements, but could however also for example have a smooth cylindrical bore to receive a spigot. In addition, such elements could also be formed in the manner of bolt elements and in which case the head of the bolt element is secured to the sheet metal part or to the plate-like component and the head would have the above described design. Finally, the element can be regarded quite generally as a functional element, whereby it is possible to realize diverse functions. For example, the function of a nut through the provision of an element with a hollow body having an internal thread, or the function of a bolt by the provision of a shaft or spigot (tubular) part, or the function of for example a pin for the clamped attachment of other components, such as carpet eyes, or electrical terminals. Ultimately, it is not the function which is important, but rather the joint or attachment between the element and the plate-like component which normally consists of a sheet metal, but with other materials such as plastic panels is also possible.
The known elements in accordance with the above referenced patents and published applications are all elements having hollow bodies which are as a rule formed as nut elements. They all offer a certain degree of security against rotation (twist-out) so that on screwing-in a bolt element a rotation of the element having the hollow body is generally avoided. Moreover, the known elements have a certain press-out resistance. Nevertheless, improved security against rotation (twist-out) and higher press-out resistances are always desirable characteristics for such elements.
It has been shown with the known elements that the elements sometimes tear out of the plate-like component (normally a piece of sheet metal) in operation and under alternating loads. The manufacture of such elements having hollow bodies is also relatively complicated and a problem exists in as much as it is difficult to simultaneously keep the weight of the element small and to make the contact surface of sufficiently large dimensions.
The undercut in the side wall of the ring-shaped recess, which is necessary to produce the required press-out resistance of the hollow body is normally achieved by subjecting the element having a hollow body to a deformation or crushing process at the peripherally extending outer surface, whereby the side wall of the ring-shaped recess is brought from an initially axially parallel position into an inclined position. In this way, the opening to the ring-shaped recess between the pilot part and the now inclined side wall is reduced in comparison to the base surface of the recess and the undercut is produced. Through this crushing process, the element having the hollow body however also has an inclined flank at the outer jacket surface adjacent to the end face confronting the component. This can lead to a situation in which the contact surface at the end face of the element becomes too small, with the contact surface being so deformed during the attachment of the plate-like component that it acts in a knife-like cutting manner under load and a high surface pressure results between the component and the element having the hollow body.
As a result of this high surface pressure, the plate-like component yields or relaxes after a few hours of operation and the element is no longer as tightly attached to the component as desired. This leads eventually to settling or relaxation, so that the prestress of a bolt inserted into the element reduces to zero, whereby the bolted connection fails.
The inclined flank at the transition from the outer jacket surface into the end face of the element however also results in an unnecessary waste of material which is generally steel, because material which is present radially outside of the contact surface at the element does not provide any contribution to the strength of the connection or of the element. In other words, the elements are heavier than is absolutely necessary, which ultimately represents an economic disadvantage.
OBJECTS AND SUMMARY OF INVENTION
An object of the present invention is to further improve an element of the above describe kind in such a way that on the one hand the security against rotation and/or the press-out resistance are improved but, on the other hand, with the manufacture of the element being simplified, and with the further development preferably also being effected in such a way that a saving of material is possible. It should also be ensured that the characteristics of the element, i.e. the connection to the sheet metal part with respect to alternating loads is improved, i.e. the danger of settling of the element and reduction of the prestress force and eventual tearing of the element out of the sheet metal part should be substantially reduced.
In order to satisfy these objects, the element of the invention is characterized in that a material supply is formed at or adjacent to the free end face of the cylindrical punch section and is displaceable at least locally by means of a die button on insertion of the element into the annular or ring-shaped recess in order to capture or clamp material of the component which has previously been pressed by the die button into the ring-shaped recess between itself and the base surface of the ring recess.
A method for the insertion of an element of this kind is characterized in that the punch section of the element is indented locally at its end face using a die button which has teeth, for example from two to six teeth, which are arranged radially within its projecting cylindrical punch section, which project radially inwardly into the central passage of the die button and are set back from the end face of the projecting cylindrical section of the die button so that material is deformed and displaced from the punch section of the element into the ring recess in such a way that it projects from the inner side wall of the ring recess, at least substantially radially into the ring recess and there overlies material of the plate-like component which has previously been pressed into the ring recess by the end face of the projecting cylindrical section of the die button and preferably clamps this material between itself and the base surface or bottom wall of the ring recess.
The invention recognizes that in some elements of t
Howard & Howard
Profil Verbindungstechnik GmbH
Wilson Neill
LandOfFree
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