AU669618B2 - Jointing method - Google Patents

Description

1 JOINTING METHOD Background of the Invention This invention relates to a method of forming joints from elongate hollow elements, particularly, though not exclusively, from aluminium extrusions. It will be appreciated that by "aluminium" is meant the commonly used alloys of aluminium, rather than chemically pure metal.

Extrusions, particularly extrusions having a square or rectangular cross section and which are hollow, are commonly made into articles, for example, furniture. The extrusions must therefore be joined together to form joints.

One method of forming joints from aluminium extrusions is described in Australian Patent No. 527528. In this patent, the extrusions are used to make a fence and are joined at the points where generally vertical posts cross with horizontal lengths. In order to form the joints, a mould is placed around the two extrusions at the point where they cross to enclose the joint. Molten aluminium is then poured into the mould, which is removed after the molten aluminium has solidified. Although this method has proved satisfactory, it requires the provision of the mould pieces, which entails some expense. In some a circumstances, the molten aluminium could melt the extrusion, thereby requiring the Sreforming of the joint. As the extrusion is surrounded by the molten metal it cannot cool.

S, Therefore the extrusion is at substantially the same temperature as the surrounding metal.

ft t 20 Furthermore, because the molten aluminium is generally of a slightly different alloy to that forming the extrusions, the extrusions tend to shink slightly more than the molten aluminium, as they cool, so that the joint becomes loose since the extrusions are e surrounded by the melt.

:0 Brief Summary of the Invention It is therefore an object of the present invention to form joints from elongate hollow 1: elements which overcomes or at least reduces the disadvantages of the known method.

There is disclosed herein method of joining two hollow elements, said method including the steps of: providing a first one of said elements with an aperture; providing a second one of said elements with an aperture; I securing the elements in a predetermined relationship so as to have adjacent portions with the apertures aligned; delivering molten metal to the interior of both elements so that the molten metal extends between the two interiors via the apertures; and allowing the metal to solidify and therefore fix the two elements together.

Preferably, the two elements are elongated and at least one of the elements has an open .nd abutting an external surface of the other element, said method further including 3 Molten aluminium 11 is poured through the uncovered end of extrusion 1 and flows into the hollow interiors 5 of each of the extrusions 1, 2 and 3 through the holes 6 as far as thc plugs 9 and into the holes 7. The molten aluminium 11 is then allowed to solidify.

As it does so, in a homogenous mass, it holds the extrusions 1, 2 and 3 together through the holes.

Furthermore, although it is still possible, in some cases, for the extrusions to melt when the melt is poured in, this is less likely to occur since it is easier to cool the extrusion from the outside, the steel plates acting both to hold the walls of the extrusion in position and to cool the extrusions. Thus, instead of an expensive special mould being required, which needs to be preheated and sprayed with die coating material, the extrusions themselves form the die.

It will be appreciated that a number of variations and modifications will be apparent to a person skilled in the art without departing from the scope of the present invention.

For example, any number of holes could be used depending on the size and strength of the joint required. If the extrusions are not of square cross-section, a number of holes can be provided at each overlapping area. If the cross-section of the extrusions is, in fact round, then some molten aluminium can remain around the outside of the extrusions, held 0 ,in place until it solidifies by the steel plates.

The joint thus produced has a better appearance than that of the prior art as the 20 soidified melt is visible only in the apertures and there is no cast joint around the outside.

In Figure 2, there is schematically depicted a joint 20 which includes two aluminium extrusions 21 and 22 which are hollow sections. The extrusions 21 and 22 are held in position by means of clamps or a jig including members 23 and 24. The extrusion 21 is 0 formed with apertures 29 which are aligned with the interior space 27 of the extrusion 22.

S 25 Plugs 25 and 26 are located so as to limit the volumes of the spaces 27 and 28.

Formed in the extrusion 22 are apertures Molten metal is delivered to the interior space 28 of the extrusion 21, and flows through the apertures 29 to the space 27. The molten metal also enters the apertures As the molten metal solidifies, the extir'sions 21 and 22 are secured together.

In the above two embodiments of the invention, as the molten metal solidifies and shrinks, a tight joint is formed by the molten metal solidifying in the holes 7 (Figure 1) and holes 30 (Figure After solidification the metal sl hifiks and draws the extrusions forming the joint together. The holes 7 and 30 provide surface against which the solidified metal bears in drawing the extrusions together. The solidified metal also bears against the surfaces 12 (Figure 1) and surface 31 (Figure 2).

t iIn a still further preferred form, a pin will pass between the apertures 30 so as to be i surrounded by the molten metal located in the space 27'. Accordingly there is provided a n ts transverse pin internally of at least one of the extrusions 21, 22. This arrangement I greatly enhances the appearance of the article as the apertures 30 are closed by a 2 the step of forming apertures in said other element so that molten metal can flow between the interiors of the elements via said apertures.

In a preferred embodiment, the elements comprise extrusions, for example extrusions of aluminium or aluminium alloy and the melt is aluminium or aluminium alloy, although the precise alloys may not be exactly the same. Preferably the elements are plugged using plugs of aluminium or aluminium alloy.

Preferably, the elements are held in a jig comprising steel plates. The plates preferably cover all the apertures and the hollow ends of the elements at the joint area except for one aperture or end through which the melt is poured, There is further disclosed herein a joint including a pair of adjacent hollow elements, with one of the elements having aligned apertures providing for communication between the interiors of the two elements, and a solidified metal located in the interiors of both elements and extending throlgh said apertures.

Brief Description of the Drawings 15 A joint from elongate hollow elements made according to one embodiment of the invention will now be more fully described, by way of example, with reference to the drawings wherein: Figure 1 is a schematic sectioned side elevation of a joint consisting of three aluminium extrusions; and S 20 Figure 2 is a schematic sectioned side elevation of a joint consisting of two aluminium extrusions.

Detailed Description of the Drawings The drawing shows three aluminium extrusions 1, 2 and 3 arranged to form a joint.

*5€4 The extrusions are of generally square cross-section, with walls 4 and hollow interior In order to join the extrusions 1, 2 and 3, holes 6 and 7 are first formed in the walls 4. The holes 6 are positioned to extend from the hollow interior 5 of a first of the extrasions 1 through a portion 8 of the wall 4 thereof to the hollow interiors 5 of extrusions 2 and 3 through their ends, which overlap portion 8 of the wall 4 of the first extrusion 1 when the extrusions are in the joined position. Holes 7 are arranged in all three extrusions 1, 2 and 3 to extend from their hollow interiors 5 through the walls 4 j to the outside at positions adjacent to the overlap portions, Plugs 9 are then positioned in each of the extrusions 1, 2 and 3 at positions beyond the holes 7 away from the joint area to block the hollow interior 5. The plugs are preferably made of aluminium and are force fitted into the hollow interiors. The extrusions are then clamped together in their joined positions between steel plates which cover the holes 7 and support the extrusions while the joint is being made. In this embodiment, the end of extrusion 1 is left uncovered.

.U AUL( 00130:hrw o' i/ preformed pin. Also as the metal in the space 27 shrinks, it will draw the extrusions 21 and 22 together. The shrinking metal will bear against the pin to draw the extrusion together.

The joint 20 can then be removed from its position held by the members 23 and 24.

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Claims (14)

1. A method of joining two hollow elements, said method including the steps of: providing a first one of said elements with an aperture; providing a second one of said elements with an aperture; securing the elements in a predetermined relationship so as to have adjacent portions with the apertures aligned; delivering molten metal to the interior of both elements so that the molten metal extends between the two interiors via the apertures; and allowing the metal to solidify and therefore fix the two elements togetler.

2. The method of claim 1, wherein the elements are elongated said first element having an open end providing the aperture thereof and abutting an external surface of the other element, said method further including providing a plurality of apertures in said second element with at least one aligned with the aperture of the first element so that molten metal can flow between the interiors of the elements via the aligned apertures.

3. The method of claim 1 or 2, wherein the elements both provide an internal surface against which the solidified metal bears as it shrinks to draw the two elements together.

4. The method of claim 3, wherein the internal surface of one of the elements is provided by a hole in a side of that element into which the molten metal flows and 20 subsequently solidifies.

The method of claim 3, wherein one of the elements has a transverse internal pin against which the metal solidifies and bears so as to provide one of said internal Ssurfaces.

6. The method of claim 5, wherein said one element has a pair of transversely 25 aligned holes between which said pin passes so as to be supported therein.

7. The method of any one of claims 1 to 6, wherein said elements and molten °.*metal are aluminium or aluminium alloys.

S The method of any one of claims 1 to 7, further including positioning plugs on the interior of each element so that the molten metal is restricted to occupy a predetermined space in each element.

9. A joint including a pair of adjacent hollow elements, with one of the elements having aligned apertures providing for communication between the interiors of the two elements, and a solidified metal located in the interiors of both elements and extending through said apertures.

10. The joint of claim 9, wherein one element has an open end abutting the other element and aligned with said apertures which are in a side of said other element. ;i

11. The joint of claim 9 or 10, further including a plug in the interior of each of ii the elements and abutting the solidified metal. i LT O iOh tj P r 0 B

12. reference

13. Figure 2,

14. A method of forming a joint, substantially as hereinbefore described with to the accompanying drawings. A joint, substantially as hereinbefore described with reference to Figure 1, or of the accompanying drawings. A joint when formed by the method of any one of claims 1 to 8. Dated 17 April, 1996 Alexander Glusa Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON *i 4 4 i i 4 .I i, 4 (I 4 CCC 4 c~rC C C i 4 C 4 4r 4C 44 4444 4 44j 44 9 JOINTING METHOD Abstract A method of joining a pair of hollow aluminium extrusions (21) and The extrusion (21) is provided with apertures (29) while the other extrusion (22) abuts the external surface of the extrusion (21) so as to be aligned with the apertures Plugs and (26) are located on the interiors of the extrusions and molten metal is delivered to the interior of the extrusion The molten metal passes through the apertures (29) to the interior of the other extrusion When the molten metal solidifies, the two extrusions (21) and (22) are secured together. Figure 2. e *C eI S .L:I 3. i I i 1NAL18TT100130tLMM