Fastening device

A fastening device comprising at least one nut, at least one support unit, and at least one spring element, with the nut, the support unit, and the spring element being constructed and matched to each other in such a way that the spring element exerts a force between the nut and the support unit.

BACKGROUND OF THE INVENTION

The present invention relates to a fastening device comprising at least one nut and at least one support unit.

For joining components to each other, it is disclosed, for example, in the prior art to use screws or nuts that are preloaded by springs (e.g. WO 00/63567, DE 25 41 826). The process of preloading the screws or nuts secures same. It is also known in the prior art to equip nuts with suitably designed washers (DE 26 01 731). The disadvantage in each of the prior-art methods is that the fastening device is made of a plurality of single components or it necessitates expensive production.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a fastening device that allows components to be fixed to each other under preload and that is preferably characterized by a compact design.

According to the invention, this object is achieved in that at least one spring element is provided, and the nut, the support unit, and the spring element are constructed and matched to each other in such a way that the spring element exerts a force between the nut and the support unit. Another name for a generic device of this type is a lock nut. In the prior art, the support unit is in the form of a washer.

Thus the spring element applies retention forces that secure the nut relative to the bolt or the screw, i.e. in general, relative to its counter component on which the nut is mounted.

In one advantageous embodiment, the nut comprises a base body, and at least one aperture is provided in the base body. The bore of the nut is dimensioned so as to match the screw or the bolt and it has a suitable internal thread.

In another advantageous embodiment, the bore is continuous or it is a blind bore. If the bore is a blind bore, it is a so-called cap nut, for example. In an embodiment, the base body is substantially cylindrical. In a further embodiment, the aperture extends substantially in the direction of the longitudinal axis of the base body. In an embodiment, the base body has on its surface force application points, by means of which the nut can be rotated as a whole around a bolt or a screw, in particular. In an embodiment, the base body is shaped like a prism, and in another embodiment like a circular cylinder. The external surface of the nut can be of any desired shape.

Provision is made in one embodiment for the base body to comprise a shoulder on at least one end region.

In another embodiment of the invention, the shoulder protrudes outwardly from the aperture. In this case, the external contour of the nut thus protrudes outwardly at one end region.

In yet another an embodiment of the invention, the shoulder is formed such that it extends substantially completely around the circumference of the base body. Alternatively, the shoulder may extend only partially around the circumference of the base body. In the first of these embodiments, the shoulder is thus made of a circumferential step, and in the alternate embodiment it is made only of segmental steps or projections, the dimensions and number of which can be specified according forces acting on the device.

In one preferred embodiment of the invention, the shoulder and the base body are a one-piece component. Alternatively, the shoulder and the base body may be a multi-part component. Thus in the first of these embodiments, the base body and the shoulder are formed integrally, and in the alternative embodiment, the shoulder may be a separate component that is, for example, welded, soldered or pressed onto the base body.

In another advantageous embodiment, the shoulder comprises a marginal lip or flange, at least in part. In this embodiment, the shoulder thus does not end as a flat surface, but it is instead delimited by a lip, the height of which can be specified as needed.

In still another embodiment, the lip is formed such that it extends substantially completely around the circumference of the shoulder. Alternatively, the lip may extend substantially, only in part, around the circumference of the shoulder.

In one advantageous embodiment, the shoulder and the lip are constructed and matched to each other in such a way that the shoulder and the lip form at least one supporting surface.

In another advantageous embodiment of the invention, the support unit is formed substantially like a sleeve. In contrast with the prior art, in this embodiment the support unit is not a washer, but instead it is sleeve-like so that, for example, the nut is partially encompassed. Thus this embodiment enables a compact and closed construction of the fastening device, for example. Advantageously, the nut and the support unit are also constructed and matched to each other in such a way that there are hardly any openings on the fastening device. In one embodiment, this applies particularly to the unmounted state of the fastening device on a bolt or a screw. The support unit is the component of the fastening device that comes into contact with a component that is to be secured by the fastening device.

In one embodiment, the support unit comprises at least one bottom portion and a side portion, and the bottom portion comprises at least one aperture. In another embodiment, the bottom portion is disk-shaped. In a further embodiment, the side portion abuts the edge of the bottom portion in the form of a circumferential surface. In an embodiment, the bore is, in particular, a through bore.

In another embodiment of the invention, the diameter of the aperture of the bottom portion of the support unit may be substantially equal to the inside diameter of the bore of the nut, or the diameter of the aperture of the bottom portion of the support unit may be smaller than an inside diameter of the bore of the nut, or the diameter of the aperture of the bottom portion of the support unit may be larger than the inside diameter of the bore of the nut.

In an embodiment, the support unit and the nut are constructed and arranged relative to each other in such a way that the aperture of the bottom portion of the support unit and the bore of the nut are disposed substantially one behind the other so as to be aligned with each other.

In one embodiment of the invention, the support unit and the nut are constructed and arranged relative to each other in such a way that at least one hollow space is located between the support unit and the nut.

In one embodiment of the invention, the support unit and the nut are constructed and arranged relative to each other in such a way that the hollow space is located substantially between the support unit and the shoulder of the nut. In this embodiment, the hollow space of the fastening device is thus located particularly between the end region of the nut, on which the shoulder is formed, and the support unit.

In another embodiment of the invention, the hollow space accommodates the spring element, at least in part. In this embodiment, the spring element is thus encompassed by the nut and the support unit. This results in an enclosed overall design that protects the spring element, for example, from contaminants and the like, which also enables simpler and safer storage and application of the fastening device.

In still another embodiment, the support unit and the nut are constructed and arranged relative to each other in such a way that the support unit is connected to the nut so as to be secured against loss. This feature also contributes to the compactness of the fastening device.

In a further embodiment of the invention, the side portion of the support unit comprises a beveled region on the side facing away from the bottom portion of the support unit.

In yet another embodiment of the invention, the support unit and the nut are constructed and arranged relative to each other in such a way that the beveled region of the side portion of the support unit has, at least in part, at least an inside diameter that is smaller than an outside diameter of the shoulder of the nut. Thus the support unit is located substantially in front of the shoulder and it also surrounds the rear side thereof so that the support unit virtually encompasses the shoulder at its margin.

In an embodiment of the invention, the beveled region has a substantially conically tapering inside diameter.

In an advantageous embodiment of the invention, the side portion of the support unit is beaded, at least in part, in the beveled region. Thus the support unit is beaded or crimped at least in one portion thereof.

In another embodiment of the invention, the support unit is provided with at least one external region which is constructed such that it exhibits substantially anti-slip properties. Thus the support unit is prevented from moving relative to the surface on which the fastening device is screwed, and damage is prevented from occurring.

In a further embodiment, the support unit and the nut are constructed and arranged relative to each other in such a way that the nut is capable of rotating relative to the support unit such that it does not transfer any substantial torque to the support unit. Thus the nut rotates substantially freely relative to the support unit.

In yet another embodiment of the invention, the spring element is constructed and disposed between the nut and the support unit in such a way that the force of the spring element acts substantially in the direction of the longitudinal axis of the nut. In this embodiment, the spring element thus applies a force in the direction in which the nut is mounted on a bolt or a screw.

In a still further embodiment, the spring element comprises at least one through opening.

In another embodiment of the invention, the spring element and the support unit are constructed and arranged relative to each other in such a way that the opening of the spring element and the aperture of the bottom portion of the support unit are disposed substantially one behind the other so as to be aligned with each other, and/or the spring element and the nut are constructed and arranged relative to each other in such a way that the opening of the spring element and the bore of the nut are disposed substantially one behind the other so as to be aligned with each other.

In still another embodiment of the invention, the spring element is constructed and arranged between the nut and the support unit in such a way that the spring element is substantially prevented from moving in the radial direction. When the spring element is substantially incapable of moving in the radial direction, then it is also unlikely for the spring element or a portion thereof to slip in front of any of the bores or openings of the fastening device and thus hinder the application of the same. That is, this embodiment substantially serves for simplifying the process of mounting the fastening device on the counter component—for example, a screw or a bolt. In a further embodiment, provision is made for locking the spring element, in particular.

In a preferred embodiment of the invention, the spring element has an outside diameter that is at least substantially equal to an inside diameter of the lip of the shoulder of the nut, and/or the spring element has an outside diameter that is at least substantially equal to an inside diameter of the side portion of the support unit.

In another preferred embodiment, the spring element comprises at least one first spring and a second spring.

In yet another preferred embodiment of the invention, the first spring and the second spring are arranged in series. Alternatively, the first spring and the second spring may be arranged parallel to each other.

In still another embodiment, at least the first spring or the second spring is a disk spring, and/or at least the first spring or the second spring is a coil spring.

In an additional embodiment of the invention, the first spring and/or the second spring has an outside diameter that is substantially equal to an inside diameter of the lip of the shoulder of the nut, and/or the first spring and/or the second spring has an outside diameter that is substantially equal to an inside diameter of the side portion of the support unit.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The accompanying drawing FIGURE shows a preferred embodiment of a fastening device according to the invention. The nut1has a through-bore11in its base body10in the embodiment shown here, which through-bore11has an internal thread by means of which the fastening device can be rotated, for example, on a bolt or a screw in order, for example, to join two components together. In the case of a cap nut1, the bore11is accordingly a blind bore.

The nut1rotates inside a sleeve-like support unit2such that the support unit2substantially does not rotate therewith.

The base body10of the nut1, which is shaped externally like a prism and internally like a circular cylinder, comprises at an end region12a shoulder13which protrudes outwardly, that is, from the bore11. The function of the shoulder13, among other things, is to provide the support unit2with a region that it can encompass so that a non-positive connection is established between the nut1and the support unit2. A delimiting lip14is further provided on the shoulder13, which delimiting lip defines a supporting surface15which serves as a lateral stop. The shoulder13and the lip14in this case are constructed to be rotationally symmetrical and to extend completely around the external surface of the base body10. In an alternative embodiment, the shoulder13and the lip14are only made of segmentally constructed units.

In this embodiment, a first spring31of a spring unit3is located on the supporting surface15. The outside diameter of the first spring31is substantially equal to the inside diameter of the lip14. As a result of this feature, the first spring31is prevented from moving in the radial direction and it therefore also cannot slip in front of the through-bore11of the nut1.

In this embodiment, the support unit2is constructed of a substantially circular bottom portion20which is adjoined by a circumferential side portion21. In the bottom portion20there is an aperture22, the diameter of which is substantially equal to that of the through-bore11of the nut1in this embodiment. In an alternative embodiment, the diameter of the aperture22in the bottom portion20is larger than the diameter of the through-bore11of the nut1. The side portion21comprises a beveled region23that narrows toward the side located opposite from the bottom portion20and engages behind the shoulder13of the nut1. In other words, the support unit2encompasses the end region12of the nut1and the shoulder13located here.

The support unit2and the nut1are constructed such that a hollow space4is located between them, in which the spring element3is disposed. The spring element3generates a spring force in the direction of the longitudinal axis of the nut1, that is, in the direction in which the nut1is screwed onto a bolt (not shown in the FIGURE). The fastening device of the invention is supported by the bottom portion20against a component, for which purpose an external region24is constructed appropriately. For example, the external region may be adapted to exhibit anti-slip properties.

The second spring32of the spring element3, which in this case is a two-part component, has an outside diameter that is substantially equal to the inside diameter of the side portion21of the support unit2, so that the second spring32is also delimited in the radial direction. The spring element3likewise comprises an opening30, with the bore11of the nut1, the opening30of the spring element3, and the aperture22of the support unit2substantially having the same inside radius in this embodiment and, moreover, all being disposed substantially one behind the other so as to be aligned with each other. In a further embodiment (not shown here), provision is made for a misaligned arrangement of the bores.

In an alternative embodiment (not shown here), there is a cover located between the shoulder13and the beveled region23, which cover substantially prevents, for example, the entry of contaminants in the region between the shoulder13and the support unit2when the nut1is in a tightened state. In one embodiment, an annular washer is provided which is disposed around the nut1and between the shoulder13and the support unit2, and which, in a further embodiment, is pressed against the beveled region23by an additional spring element.