FASTENING ELEMENT, METHOD AND USE HEREOF

Abstract: Fastening element (1) for the assembly of a hollow profile (2) against a second profile (3), said fastening element (1) comprising a front surface (5) and a rear surface (6) and also side and end surfaces (11, 9, 10), and where the front (5) and rear surface (6) are substantially plane-parallel, and at least the one front or rear surface comprises a longitudinal recess (7), the depth of said recess substantially being less than the diameter of a securing element (4) for engagement in the recess. There is achieved a fastening element which can be used for existing hollow profiles, without these profiles necessarily having to be configured with explicit elements for the securing of the fastening element, and furthermore where such a strong joint is provided between the hollow profile and a second profile that the fastening element makes it possible for door frames to be assembled, where as mentioned above the foot panel in particular must withstand great forces in the corner joint when persons tread on the panel.

Description: FASTENING ELEMENT. METHOD AND USE HEREOF The invention concerns a fastening element for the assembly of a hollow profile against a second profile, said fastening element comprising a front surface and a rear surface and also side and end surfaces. The invention also concerns a method for the assembly of a hollow profile with a second profile in the formation of a corner joint and comprising at least one fastening element, said fastening element being placed in an inner cavity in the hollow profile, and where a securing element, preferably in the form of a screw, is placed through the second profile and grips firmly in the fastening element, in that said fastening element is wedged down in the cavity. The invention also concerns the use of both the fastening element and the method. From US 5,205,102 there is known a fastening element for the assembly of corners, primarily in windows and doors, where the fastening element is wedged down in the hollow profile, after which a tightening of a profile to the hollow profile is effected by a screw being inserted through the one profile down into the fastening element. The fastening element is fastened to the hollow profile itself by means of a pair of locking arms which are angled in relation to the front and rear surface of the fastening element, on each of which surfaces there is provided a boss which engages in recesses in the inner hollow profile and thus locks the fastening element in the cavity, and after which a tightening of the first profile against the hollow profile can take place. Such a solution requires that the hollow profile is configured especially for such a wedge arrangement, i.e. that a hole is drilled where the hemispherical bosses on the arms can enter into downwards engagement. Moreover, such an assembly will be relatively weak and will thus not be able to tolerate, for example, assemblies of lower frames to side frames, where great forces are transferred in the corner joints when the lower frame is trodden upon. The object of the present invention is thus to provide a fastening element which can be used for existing hollow profiles without these hollow profiles necessarily having to be configured with explicit elements for the securing of the fastening element, and furthermore where the resulting assembly between the hollow profile and a second profile is so strong that the fastening element makes it possible to assemble door frames, where as mentioned above the under frame in particular must withstand great forces in the corner joint when persons tread on the foot panel. This object is achieved with a fastening element of the type disclosed in the introduction, and where the front and rear surfaces are substantially plane-parallel, and that at least the one front or rear surface comprises a longitudinal recess, the depth of said recess substantially being less than the diameter of a securing element for engagement in the recess. The fastening element is thus unique in that it is placed in the inner cavity of a hollow profile so that the one end surface of the fastening element lies flush with the outer end of the hollow profile. A securing element, preferably a screw, is subsequently inserted through the second profile which must be fastened to the hollow profile, and the screw now finds its way down to the recess which is configured in the fastening element, and which as a consequence of this fastening element lying with its recess tight up against the inner surface of the hollow profile, will cut its way down partly into the inner surface of the hollow profile and partly in the recess itself in the fastening element, whereby a particularly robust assembly is achieved. By providing a fastening element according to the invention and as further disclosed in claim 2, it is achieved that the securing element in the form of a screw can assume any length, and that maximum assembly strength is achieved. By providing a fastening element according to the invention and as further disclosed in claim 3, it is achieved that the securing element enters into a gripping engagement with the recess in an optimum manner. By providing a fastening element according to the invention and as further disclosed in claim 4, it is achieved that when the screw comprises a conical head, it can be screwed far down into the fastening element. By providing a fastening element according to the invention and as further disclosed in claims 5 and 6, it is achieved that the fastening element also receives help from the subsequent wedge and by the elastic deformation of the arms for fastening in the hollow profile, and thus its engagement in the hollow profile is optimised. By providing a fastening element according to the invention and as further disclosed in claim 7, it is achieved that it is easy to place the fastening element in the profile, in that the narrow end is first pressed down into the profile, after which the fastening element can be pressed completely into the profile as a consequence of the elasticity which is provided by means of the arms. By providing a fastening element according to the invention and as further disclosed in claim 8, it is achieved that the plastic deformation is made possible, in that the cutting of a thread is effected as a consequence of the differences in material hardness. The invention also concerns a method as disclosed in claim 9, whereby a strong assembly is achieved in a simple manner, and which as disclosed earlier allows e.g. the assembly of door frames. By further specification of the method as disclosed in claims 10 and 11, the fastening element achieves optimum gripping engagement when it is placed in the cavity. By another specification of the method as disclosed in claim 12, at least one fastening element is optionally joined by at least one separate spacer element. The invention also concerns the use of the fastening element and the method as disclosed in claims 13, 14 and 15. The invention will now be described in more detail with reference to the drawing, where fig. 1 shows an example of a fastening element according to the invention, seen in perspective from above, fig. 2 shows the example of a fastening element shown in fig. 1, seen in perspective and from below, and fig. 3 shows an example of the fastening element shown in figs. 1 and 2 seen in situ in a hollow profile and assembled with a second profile. Fig. 1 shows a fastening element 1 which is brick-shaped and comprises a front surface 5 and a rear surface 6, said front and rear surfaces being plane-parallel, and where on the front surface along the centre axis of the element there is provided a longitudinal recess 7 along the full length of the element. Said recess 7 can have a semicircular or rectangular configuration, but it is most important that the breadth of this recess at the top and measured at the front suiface 5 corresponds to the diameter of the securing element in the form of a screw which must be screwed down into the recess. For example, if the securing element is a 5mm screw, the breadth will thus be 5mm. The depth of the recess is less than the diameter of the screw and preferably greater than half of the diameter of the screw. The side surfaces 11 of the fastening element 1 extend in such a manner that the fastening element has a wedge shape when a line is drawn from the first end surface 9 of the fastening element to its second end surface 10. In the example shown, the side surfaces are configured in such a way that the shape of the fastening element can almost be compared with that of an hourglass, where the side surfaces converge towards each other and then extend outwards in the form of a foot, but where the breadth of this foot 16 is less than the breadth of the fastening element measured at the first end surface 9. Laterally to the longitudinal recess, the fastening element comprises slots or cut-outs 12 which are disposed symmetrically around the centre axis of the recess, which in turn is coincident with the centre axis of the fastening element. The slots 12 extend from the first end surface, which first end surface is that surface into which the securing element is screwed, and extend through the full thickness of the fastening element and thus break both the front surface 5 and the rear surface 6. It can be expedient that at a distance from the starting point of the cut-outs in the first end surface 9, the slots are milled out to form a longitudinal cavity 15, whereby the arms 13 and 14, which thus lie laterally to the slots, assume a greater elasticity, whereby the wedge effect is reinforced when the fastening element is placed in the cavity. It is expedient for the recess 10 to start at the first end surface 9 with a conical shape 8 which will enable the screw to be screwed in deeper, which is of significance when the second profile is, for example, a plate with very small thickness, and where the conical shape from the screw will be able to be seen on the rear surface of the second profile, and thus must be pressed down in the fastening element itself. It is expedient for the fastening element to be made of a plastic material, for example polyethylene, and here it is important that the hardness of the fastening element is relatively great, but not greater, however, than the securing element 4 can cut a thread in this when it is screwed in. It is similarly important that the hollow profile in which the element is placed has a hardness which does not exceed the hardness of the securing element 4, so that the cutting of a thread also takes place in the hollow profile. These conditions concerning the hardness of the relevant materials are relevant in the case when the cutting of a thread is not carried out with a thread cutting element before the screwing-in of the securing element. The placing of the fastening element in the second profile 3 will now be explained with reference to fig. 3, where the fastening element is placed with its second end surface deepest in the profile and preferably with the first end surface lying flush with the end of the hollow profile. The second profile 3, which can be made of metal, wood, plastic etc. is now placed with right-angled abutment against the cut-off straight hollow profile, and a screw is screwed in. The screw finds its way to the recess, in that the fastening element is placed in the cavity in such a manner that, due to the arms, the side surfaces wedge themselves firmly against surfaces on the inside of the cavity, and where between the front surface of the fastening element and that surface in the cavity it faces towards there is a certain clearance, so that there is room for a securing element in the form of a screw to find its way and be screwed into the recess which forms the one wall, and where the inner surface of the cavity constitutes the second wall. It is thus important that the hardness of the hollow profile and the fastening element is selected so that the screw can cut a thread in both parts, and where it is most important, however, that the screw can cut a thread in the fastening element. The screw is screwed in completely, and with this an assembly of great strength is provided. The system is especially applicable for the assembly of door frames, where the joints at the top and bottom thus do not need to be formed by mitring, but where use can thus be made of straight profiles which, all other things being equal, are easier to assemble and to produce, and where assembly also results in such great strength that the foot panel can withstand great forces, in that the fastening element sits immovably firm down in the hollow profile itself as a consequence of the clamping effect which occurs when the screw is screwed down and thus presses against both the fastening element and the profile, and whereby a thread is cut. Consequently, it is also important for the dimensions of the fastening element that its thickness corresponds substantially to the distance between the inner cavity of the hollow profile, though such that there is a certain clearance in that there must be room in order that the screw can be fastened as disclosed. The fastening element can, for example, be configured with a length of 50mm measured from first to second end surface, and where the breadth of first end surface can be 28- 29mm and the breadth of second end surface can be 25 -26mm. It can be expedient for the thickness of the fastening element to be 6.5mm for insertion in hollow panels with an inner distance between the walls of 7.2mm. It must be mentioned, however, that the actual thickness of the plate can decrease from the first end surface towards the second end surface. The breadth of the recess will depend on the chosen screw, and thus for a 5mrn-broad screw a 5mm-broad recess is chosen. It should be noted that the length of the fastening element also depends on the length of the screw, and thus that the above- mentioned dimensions correspond to a screw of 50mm. In this case, the depth of the recess will typically be around 3.2mm. The cross-section of the recess is typically partly circular to semicircular. In another embodiment (not shown) of the invention where one is to use the method according to any of the claims 9-11, it is suggested that more than one fastening element (1) according to any of the claims 1-8 could be used and for instance together with a separate spacer element. If for instance two fastening elements (1) is used they could be placed in a hollow profile (2) for instance back to back or with a separate spacer element (not shown) between their backsides i.e. rear surfaces (6). Hereby a more complex hollow profile (2) could be used without changing neither the shape nor the manufacturing process of the "standard" fastening element (6), i.e. no "special" element has to be manufactured only one or more of the said separate spacer element, which could have any desired appropriate, cheep to manufacture "standardized" such as rectangular, square or another form, would have to be added the assembly.

Claims: CLAIMS 1. Fastening element (1) for the assembly of a hollow profile (2) against a second profile (3), said fastening element (1) comprising a front surface (5) and a rear surface (6) and also side and end surfaces (11, 9, 10), characterized in that the front (5) and rear surface (6) are substantially plane-parallel, and that at least the one front or rear surface comprises a longitudinal recess (7), the depth of said recess substantially being less than the diameter of a securing element (4) for engagement in the recess. 2. Fastening element according to claim 1, characterized in that the recess (7) extends for the full length of the front and/or rear surface. 3. Fastening element according to claim 1 or 2, characterized in that the greatest breadth of the recess lies at the surface (5) from which it extends, and corresponds substantially to the diameter of the securing element (4). 4. Fastening element according to any of the foregoing claims, characterized in that the recess (7) comprises a conical enlargement (8) at the first end surface (9). 5. Fastening element according to any of the foregoing claims, characterized in that on each side of the recess and for the whole of its thickness, the fastening element (1) comprises at least two slots (12) which extend from the first end surface (9) and at a first distance from same, the length of said slots being less than the length of the fastening element (1), whereby a first (13) and a second (14) arm are formed. 6. Fastening element according to any of the foregoing claims, characterized in that at a second distance less than the first distance, the slots (12) comprise an enlargement measured in the direction at right-angles to the longitudinal axis of the element in the formation of a through-going and longitudinal cavity (15). 7. Fastening element according to any of the foregoing claims, c h a r a cte riz e d in that the breadth of the fastening element, measured at the first end surface (9), is greater than the breadth measured at the second end surface (10). 8. Fastening element according to any of the foregoing claims, c h a r a ct e riz e d in that it is produced in a material with a hardness which is less than the hardness of the securing element (4). 9. Method for the assembly of a hollow profile with a second profile in the forming of a corner joint and comprising at least one fastening element, said fastening element being placed in an inner cavity in the hollow profile, and where a securing element, preferably in the form of a screw, is placed through the second profile and grips firmly in the fastening element, in that said fastening element is wedged down in the cavity, c h a ra c te riz e d in that the front and rear surfaces of the fastening element are substantially plane-parallel with the inner walls of the hollow profile when the fastening element is placed in the profile, and in that the fastening element is wedged down in the cavity with abutment of the side surfaces of the element against the inner surfaces of the hollow profile, and in that the front surface or the rear surface of the element comprises a longitudinal recess in which the securing element is screwed down for the establishing of a connection between the recess and inner surface of the hollow profile. 10. Method according to claim 9, ch a r a ct e riz ed in that the connection is established by the cutting of a thread in the recess and in the inner surface of the hollow profile. 11. Method according to claim 9 or 10, ch a ra ct e riz e d in that in being wedged down in the main profile, the fastening element is elastically deformed due to at least one preferably two arms which are brought about by slots which are cut in the fastening element. 12. Method according to claim 9, 10 or 11, ch a r a cte riz e d in that at least one or more fastening element (6) in being wedged down in the main profile, and/or optionally at least one additionally separate spacer element is placed in the hollow profile between the said at least one fastening element or one of the profile walls. 13. Use of a fastening element according to claims 1-8 for the method disclosed in claims 9-12. 14. Use of a fastening element according to claims 1-8, and use of the method according to claims 9-12 for hollow profiles of metal or plastic materials. 15. Use of a fastening element according to claims 1-8, and use of the method according to claims 9-12 for the assembly of corners in windows, window frames and door frames.

Inventors: SMEDEGAARD KAJ, SMEDEGAARD, KAJ
Applicants: SMEDEGAARD KAJ, VKR HOLDING AS, SMEDEGAARD, KAJ, VKR HOLDING A/S
Application year: 2001
Main classification: E06B3
IPC codes: E06B3