Method and device for securing components on peripherally closed hollow profiles
The invention relates to a method for fixing components (2) to peripherally closed hollow profiles (3). Walls (4,5) of the component (2) and the hollow profile (3) are connected to each other in a positive fit. In order to fix the component (2) to the hollow profile (3) in a simple manner, independent or position, the walls (4,5) to be joined are placed in an adjacent position and are locally impinged upon by external pressure such that the walls (4,5) a repressed inside (12) the hollow profile (3) and a double-walled indentation (10) is formed, wherein the walls (4,5) are clamped against each other.
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The invention relates to a method for fastening components to initially closed hollow profiles, and a device for that purpose.
DE 196 19 626 C2 discloses a device in which hangers are affixed to a hollow profile such that both the hanger and the hollow profile are placed in engravings of a high internal pressure forming tool and then the section is subjected to a high internal fluid pressure. Under this pressure the material of the hollow profile flows radially outward and at the location of the hanger it flows conformingly around the surface of the hanger which has an undercut shape so that an interlocking bond is established between the hanger and the hollow profile. The described fastening of the hanger to the hollow profile is possible, however, only within the expanded area between the axial sealing and punches that close the ends of the hollow profile. Furthermore, the flexibility of the method is limited by the fact that the shape of the high internal pressure forming tool permanently establishes the shape and location of the bond, so that in the case of different requirements as to the position and kind of the interlocking bond different tools are necessary. The result is great expense and investment in the device.
The invention is addressed to the task of improving a method of that kind and a device also of that kind so that a secure fastening of the component to the hollow profile is made possible in a simple manner, regardless of the point of fastening.
The problem is solved according to the invention by the invention described and claimed below.
Inasmuch as an external pressure is applied to the adjacent walls of the hollow profile and hanger by means of a pressure medium and thus they are forced inward into the interior of the hollow profile thus forming a double-walled indentation, a clamping of the walls is achieved which assures a secure fastening of the hanger to the hollow profile. This indentation is possible axially and radially at any point on the hollow profile and is freed of any specific shapes of the receiver of the hollow profile and hanger, so that not only the receiver but also the entire device can be configured in a very simple manner. With the method of the invention a simple possibility of fastening is offered that is reliable and practical for hollow profiles that are to be fastened together, which otherwise can not be fastened together in a reliable manner, especially hollow profiles shaped by internal high pressure with attachments or in some cases to other hollow profiles made in the same manner.
Appropriate developments of the invention can be found in the sub-claims; otherwise the invention is further explained below with the aid of several embodiments represented in the drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
Although in this case a certain interlocking clamping together of the walls 4 and 5 is achieved, it is desirable if the walls 4 and 5 are forced by the plunger 8 into the gap 7 such that they are forced against the wall 9 of the gap in order to improve the clamping in the manner of a press fit (
In another embodiment according to
It is a more economic process and shortens the cycling time, however, if the hollow profile 3 is under high internal pressure while the plunger 8 is forcing the walls 4 and 5 inward. The counter pressure which would be created in the foregoing example against the plunger 8 and the walls 4 and 5 by contact with the notch wall 9 for the forming operation is here provided by the high internal pressure. Or account of the forces of the internal high pressure and the plunger 8 acting on the face 17 of the indentation, a sideways displacement of the material of the hollow profile and component, rendered fluid by the high internal pressure, takes place. The end face 17 is made thinner as a result, leading to an accumulation of the hollow profile and component material in the edge area 18 of the end face 17. This has the effect that all around in this area 18 undercut areas form in the indentation 10, so that, in a manner improved beyond the preceding embodiment, the result is a junction similar to a through-joint, which is inseparable in any direction (axial and radial).
A more intense formation of the undercut surfaces is achieved by using a plunger 8 according to
In an alternative to the two embodiments described, in the case where the receiver is in the form of a high internal pressure shaping tool 15, a mandrel 6 can be driven into the hollow profile 3. In this case the mandrel 6, in a dual function, can advantageously form both the matrix for the plunger 8 and the axial sealing plunger of the tool 15.
It has been assumed up to now that the forcing means is the plunger 8. In another embodiment the forcing means, however, can also be a fluid pressure column 25, as seen, for example, in
After the shaping of the indentation 10, in order to remove the mandrel 31 from the forming tool 26 with the release of the undercut surfaces, the mandrel 31 is divided into two parts 34 and 35 along its length. Each part 34 and 35 has a section of the recess 32 which is formed at the face 36 of each part 34 and 35, so that when the two ends 36 are in contact with one another the whole recess 32 is the result. To assure that the two parts 34 and 35 will be together during the impressing process it is desirable to screw the two parts 34 and 35 together. After the indentation 10 has been completed, the screw fastening is released and the two parts 34 and 35 are drawn in opposite directions out of the hollow profile 3 and the forming tool 26. Alternatively, parts 34 and 35 can be driven by hydraulic cylinders and held securely in the end position within the hollow profile 3. This certainly shortens the cycle in comparison with screw fastening, but requires expensive equipment. Furthermore, it is alternatively conceivable to hold the two paarts 34 and 35 together in a simple manner with a clamping device, which can be released quickly if necessary, after they reach the end position against one another.
To expedite the formation of the undercut surfaces, and for improvement in the uniform filling out of the radii of the recess 32, and thus to achieve optimum mating between walls 4 and 5, the mandrel 31 has an axial fluid passage 37 from which a radial passage 38 branches off, which leads into the recess 32 at its bottom 39. Passages 37 and 38 can be only in one of the parts 34 or 35, or—as shown in
Another advantageous variant is shown in the embodiment seen in
In an additional advantageous embodiment according to
For additional strengthening of the bond between the walls 4 and 5, they can be brushed or coated with an adhesive before they are brought together, the tackiness of the adhesive being activated, preferably by heat treatment after the double-walled indentation is formed. As an alternative the walls 4 and 5 can also be coated with a solder, and after the indentation 10 is formed they can be soldered together by heat treating the solder and the component 2 and hollow profile 3 in an oven.
The hollow profile 3 itself can be made from pipe skelp rolled and then welded along the seam. In like manner, extruded or rolled shapes can be considered. However, two superimposed skelps can be shaped by means of internal high fluidic pressure, and the impression can be performed in an economic manner during or after formation by internal high fluidic pressure. The hollow profile 3 can have a circular cross section like the tubular raw material or it can have other cross-sectional shapes which can be obtained by flattening, bending and pressing or the like.
Otherwise, the indentation 10 can also run like an annular groove around the component 2 and the hollow profile 3. The compression means can be the pressure column 25 as well as a segmented annular die surrounding component 2 as well as hollow profile 3.
Moreover, an additional advantage of the embodiments in
Claims
1-25. (canceled)
26. A method for fastening a component to a peripherally closed hollow profile, the method comprising the steps of:
- applying an external pressure to an area of walls of the component and hollow profile, so that the walls of the component and hollow profile in the area are clamped to one another and are forced into the interior of the hollow profile.
27. The method according to claim 26, wherein the step of applying the external pressure includes applying the external pressure mechanically using a plunger.
28. The method according to claim 26, wherein the step of applying the external pressure includes applying the external pressure using a pressurized fluid medium.
29. The method according to claim 26, comprising fastening the component to the hollow profile with the wall of the component inside of the hollow profile wall.
30. The method according to claim 26, comprising fastening the component to the hollow profile with the wall of the component outside of the hollow profile wall.
31. The method according to claim 26, wherein the component is a second hollow profile and is fitted together with the first hollow profile before the component is fastened to the first hollow profile.
32. The method according to claim 26, wherein the component has a flange that is fastened to the hollow profile.
33. The method according to claim 26, comprising forcing the area of the walls into a recess formed on the circumference of a mandrel so that the wall of the component or of the hollow profile is in contact with a wall of the recess in a contour-matching manner.
34. The method according to claim 26, comprising forming undercuts by applying a counter-pressure from the interior of the hollow profile on the walls.
35. The method according to claim 34, comprising generating the counter-pressure by an internal high fluid pressure in the hollow profile.
36. The method according to claim 34, wherein the step of forming undercuts including forming the undercuts by a radial expansion of a spreadable end of a plunger.
37. The method according to claim 26, wherein, before the walls of the component and hollow profile are fastened to one another, at least one of the walls is applied with an adhesive, and wherein, after the formation of a double-walled indentation, the adhesiveness of the adhesive is activated by heat treatment.
38. The method according to claim 26, wherein, before the walls of the component and hollow profile are fastened to one another, at least one of the walls is coated with solder, and wherein, after the formation of a double-walled indentation, the component and the hollow profile are soldered together by heat treatment of the solder.
39. The method according to claim 26, wherein the hollow profile is formed from two superimposed skelps by internal high fluid pressure, and wherein the pressing is performed during or after the internal high pressure forming of the skelps.
40. Apparatus for fastening a component to a peripherally closed hollow profile, comprising:
- a receiver in which the hollow profile and the component are held such that walls of the hollow profile and of the component are in contact with one another;
- a device for applying a pressure medium to clamp the walls together and to force the walls into the interior of the hollow profile with a formation of a double-walled indentation, wherein the pressure medium is disposed outside of the hollow profile.
- a die within the hollow profile, wherein the pressure medium pushes the walls into the die to form a double-walled indentation for the clamp- fastening of the component to the hollow profile.
41. The apparatus according to claim 40, wherein the pressure medium is a fluid pressure.
42. The apparatus according to claim 40, wherein the pressure medium is a plunger.
43. The apparatus according to claim 40, wherein the receiver is an internal high pressure forming tool.
44. The apparatus according to claim 40, wherein the die is a mandrel which can be pushed into the hollow profile and has a recess, into which the walls can be pushed by the pressure medium.
45. The apparatus according to claim 44, wherein the mandrel is an axial plunger forming an internal high pressure forming tool.
46. The apparatus according to claim 45, wherein the indentation has undercut surfaces.
47. The apparatus according to claim 46, wherein the undercut surfaces are in the form of a dovetail.
48. The apparatus according to claim 44, wherein the mandrel has an axial fluid passage from which a radial passage branches, which radial passage opens in the indentation.
49. The apparatus according to claim 42, wherein the plunger can be spread open at its end.
50. The apparatus according to claim 40, wherein the die is a diaphragm or tubular bellows, which can be introduced into the hollow profile and is supported internally during insertion.
Type: Application
Filed: May 22, 2003
Publication Date: Jul 13, 2006
Applicant: DaimlerChrysler AG (Stuttgart)
Inventor: Stefan Schwarz (Lunen)
Application Number: 10/520,354
International Classification: B21D 39/00 (20060101);