Blind rivet-nut and method for securing a component to a carrier

A blind rivet-nut having an annular-flange-like setting head and a hollow shaft for securing a blind rivet-nut in an opening of a carrier. The hollow shaft has a free end having a threaded portion for receiving a threaded element of a tensioning tool. A clamping portion adjacent to the setting head forms a bead-like deformation when the tensioning tool is used to clamp the carrier between the bead-like deformation and the setting head. A threadless shaft portion is formed between the clamping portion and the threaded portion. The threadless shaft portion is threaded by a thread self-rolling or thread self-tapping fastener. The fastener is received in a positive-locking manner when the fastener is screwed into the thread formed on the previously threadless shaft portion. A method is also disclosed for securing a component to a carrier by a blind rivet-nut.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims foreign priority benefits under 35 U.S.C. § 119(a)-(d) to DE 10 2016 212 024.7 filed Jul. 1, 2016, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a blind rivet-nut for securing a component to a carrier by means of a blind rivet-nut and a method for securing a component to a carrier by means of a blind rivet-nut.

BACKGROUND

A blind rivet-nut set on a carrier, in particular a component produced from sheet metal, is intended to be securely connected in order to provide it with a securing thread which can be used to secure a bolt or a screw. Blind rivet-nuts can further serve to connect two or more thin-walled carriers or components to each other.

A rivet-nut comprises a setting head which is intended to contact a first side of the carrier and a hollow shaft which is configured to be inserted in a through-hole of the carrier. The hollow shaft comprises a clamping portion which is intended, under the action of an axial pulling force, to become deformed to form a bead which moves into abutment with the second side of the carrier so that the carrier is clamped to ensure the retention of the nut on the carrier. Furthermore, the nut is set in a blind manner the nut is set in the region of the second side of the carrier without access to this second side. Generally, the shaft of a blind rivet-nut comprises a threaded portion for receiving a threaded element, wherein the threaded element enables the axial pulling force which is required to deform the clamping portion to be applied to the hollow shaft. This threaded portion is subsequently used to screw in a screw or a bolt which is intended to be secured to the blind rivet-nut. Such a blind rivet-nut is known, for example, from DE 20 2015 100 359 U2.

The screwing of the threaded element into the threaded portion requires precise straight positioning and centering of the threaded element on the threaded portion so that the threaded element is not placed in an oblique manner on the thread and consequently becomes jammed during the screwing-in operation.

SUMMARY

Against this background, an object of the present invention is to provide a blind rivet-nut which is improved with respect to use during large-batch production and in which tilting and jamming of a screw or a bolt which is intended to be secured to the blind rivet-nut is prevented during screwing into the blind rivet-nut to the greatest possible extent. Furthermore, a securing arrangement and a securing method having the same advantageous properties are intended to be set out.

It should be noted that the features which are set out individually in the claims can be combined with each other in any technically advantageous manner and set out other embodiments of the invention. The description further characterizes and specifies the invention with specific references to the Figures.

According one aspect of the invention, a blind rivet-nut for blind riveting in an opening of a carrier comprises, for example, a thin-walled metal sheet, an annular-flange-like setting head and a hollow shaft. The hollow shaft has at the free end thereof opposite the setting head a threaded portion for receiving a threaded element, for example, a screw or a bolt, and a clamping portion which is adjacent to the setting head. The clamping portion is intended, during a setting operation of the blind rivet-nut on the carrier, to become deformed in a bead-like manner in order thus to clamp the carrier between the bead-like deformation of the clamping portion and the setting head. The invention further makes provision for an additional threadless shaft portion to be formed in the hollow shaft between the clamping portion and the threaded portion. This threadless shaft portion is suitable and constructed for receiving a thread self-rolling or thread self-tapping screw or bolt in a positive-locking manner therein when the screw/bolt is screwed into the shaft portion.

The term thread self-rolling is intended to be understood to be a non-cutting introduction of a thread by means of the screw or the bolt into the thread-free shaft portion of the blind rivet-nut when it is screwed into the threadless shaft portion, whereas a thread self-tapping operation is intended to be understood to be introduction involving cutting of the thread by means of the screw or the bolt into the threadless shaft portion of the blind rivet-nut when it is screwed into the threadless shaft portion. As used herein the term “self-tapping” is intended to refer to both self-rolling and self-tapping fasteners. A positive-locking receiving of the screw or the bolt in the shaft portion is produced when the screw or the bolt has introduced the thread into the threadless shaft portion and the screw or the bolt is screwed into this thread. The screw or the bolt serves, for example, to secure another component to the blind rivet-nut or to the carrier.

A specific advantage of the blind rivet-nut according to the invention is that the securing screw or the securing bolt can neither tilt nor become jammed when it is screwed into the threadless shaft portion since it forms the thread itself only when it is screwed into the threadless shaft portion. Furthermore, the threadless shaft portion advantageously leads to a self-centering of the securing screw or the securing bolt in the threadless shaft portion of the blind rivet-nut during the screwing-in operation.

An advantageous embodiment of the invention makes provision for the threadless shaft portion to have a hole diameter which is smaller than the diameter of the clamping portion and greater than the diameter of the threaded portion. It can thereby be ensured that only the clamping portion with the largest hole diameter becomes plastically deformed during a setting operation of the blind rivet-nut on the carrier, but not the threadless shaft portion and the threaded portion.

The wall thickness of the threadless shaft portion may be sized in such a manner in this instance that the threadless shaft portion substantially does not become plastically deformed during the setting operation of the blind rivet-nut on the carrier.

Furthermore, the wall thickness of the threadless shaft portion may always be sized in such a manner that an inner thread can be rolled or cut in this shaft portion. In this instance standards for forming threads known per se to the person skilled in the art can be considered and complied with.

According to another aspect of the present invention, there is provided a securing arrangement which has a component which is secured to a carrier by means of a blind rivet-nut, wherein the blind rivet-nut is blind-riveted in conventional manner in an opening of the carrier and the component is secured to the blind rivet-nut by means of a screw or a bolt. In this instance, the invention makes provision for the blind rivet-nut to be constructed in accordance with one of the embodiments described above. Furthermore, the screw or the bolt is a thread self-rolling or thread self-tapping screw or bolt and this screw or bolt is screwed into the shaft portion of the blind rivet-nut, which portion is threadless before the screwing-in operation, to form a positive-locking receiving member therein for itself.

Other embodiments of the securing arrangement according to the invention whose advantages and effects will be appreciated directly from the preceding description of the blind rivet-nut according to the invention and can accordingly also be applied to the securing arrangement.

According to yet another aspect of the present invention, a method for securing a component to a carrier by means of a blind rivet-nut which is constructed in accordance with one of the embodiments described above is provided. The method has at least the following steps: setting the blind rivet-nut in an opening of the carrier so that the clamping portion of the blind rivet-nut becomes deformed in a bead-like manner during the setting operation of the blind rivet-nut and the carrier is clamped between the bead-like deformation of the clamping portion and the setting head of the blind rivet-nut; and securing the component to the blind rivet-nut by screwing a screw or a bolt into the shaft portion of the blind rivet-nut, which portion is threadless before being screwed in, wherein the screw or the bolt is thread self-rolling or thread self-tapping in order to form a positive-locking receiving member for itself in the threadless shaft portion.

In this instance, there are also produced additional embodiments of the securing method according to the invention, whose advantages and effects directly from the preceding description of the blind rivet-nut according to the invention and can accordingly also be applied to the securing method.

Other features and advantages of the invention will be appreciated from the following description of an embodiment (which is not intended to be understood to be limiting) of the invention which will be explained in greater detail below with reference to the drawings. In the schematic drawings:

DETAILED DESCRIPTION

In the different Figures, components which are equivalent in terms of their function are always given the same reference numerals so that they are generally also described only once.

FIG. 1is a cross-section of an embodiment of a blind rivet-nut1made according to this disclosure before a setting operation on a carrier2.FIG. 1shows that the blind rivet-nut1has an annular-flange-like setting head3and a hollow shaft4which is integrally connected to and adjacent to the setting head3.

The hollow shaft4of the blind rivet-nut1illustrated inFIG. 1comprises at the free end thereof opposite the setting head3a threaded portion5for receiving a threaded element6which is fitted, for example, to a tension screw7as shown inFIG. 1. The tension screw7serves to set the blind rivet-nut1on the carrier2, as will be further explained with reference toFIG. 2.

Furthermore, the hollow shaft4has a clamping portion8adjacent to the setting head3that deforms in a bead-like manner during a setting operation of the blind rivet-nut1on the carrier2. The bead-like deformation9of the clamping portion8clamps the carrier against the setting head3, as illustrated inFIG. 2.

In the embodiment of the blind rivet-nut1illustrated inFIG. 1, a threadless shaft portion10is constructed between the clamping portion8and the threaded portion5. This threadless shaft portion10, or sleeve, is constructed to receive a thread self-rolling or thread self-tapping screw11or bolt in a positive-locking manner when the screw/bolt is screwed into the shaft portion10, as illustrated inFIG. 3.

FIG. 1further shows that the threadless shaft portion10has a hole diameter12which is smaller than the diameter13of the clamping portion8and greater than the diameter14of the threaded portion5. The hollow shaft4of the blind rivet-nut1as shown inFIG. 4has a substantially constant outer diameter along the clamping portion8, the threadless shaft portion10and the threaded portion5. Different wall thicknesses are provided for the clamping portion8, the threadless shaft portion10and the threaded portion5. The wall thickness of the threadless shaft portion10is sized in such a manner that an inner thread can be rolled or cut in the threadless shaft portion10. The blind rivet-nut1when set on the carrier2plastically deforms the clamping portion8but does not plastically deform the threadless shaft portion10during the setting operation.

As indicated inFIG. 1, the blind rivet-nut1is first introduced into the opening defined by the carrier2and a suitable setting tool, such as a tension screw7is used to set the blind rivet-nut1. The threaded element6of the tension screw7is screwed into the threaded portion5of the blind rivet-nut1to apply an axial pulling force to the hollow shaft4of the blind rivet-nut1.

FIG. 2is a cross-section of the blind rivet-nut1fromFIG. 1after setting the blind rivet-nut on the carrier2. The clamping portion8of the blind rivet-nut1is plastically deformed by the axial pulling force applied by the tension screw7. The plastic deformation creates the bead-like deformation9of the clamping portion8. The carrier2is clamped between the bead-like deformation9of the clamping portion8and the setting head3after the setting operation.

FIG. 3is a cross-section of the blind rivet-nut1ofFIG. 2set on the carrier2and to which another component15, for example, a metal sheet, is secured by means of the securing screw11. The thread self-rolling or thread self-tapping securing screw11is screwed into the shaft portion10to secure the component15to the blind rivet-nut1or to the carrier2. The shaft portion10is threadless before the self-tapping screw is screwed into the shaft portion10. The self-tapping screw forms, rolls or cuts a thread into shaft portion10and the screw11is received in a positive-locking manner in the thread.

The blind rivet-nut according to the invention is used to secure a component to a carrier by means of a thread self-rolling or thread self-tapping screw or bolt. The blind rivet-nut, the securing arrangement and the securing method are, however, not limited to the embodiment described herein, but instead also include other embodiments which have the same effect.