FI63874B - OVER MASKIN FOER FRAMSTAELLNING AV NAETMETALL - Google Patents

Description

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Patent · OCh registerstyrelsen 'Anrtkan utlagd och utl.ikriftan publlcarad 31.09.83 (32) (33) (31) Pyy * · «/ atuolkaui-ea | * rd prloritat l8.09.75 20.10.75 Australia-Australien (AU) PC 322 0 PC 3621 (71) Ampliform Pty. Limited, 21 George Street, Thebarton, Australia-Australia (AU) (72) Harold Rex Jury, Thebarton, Australia-Australia (AU) (7 * 0 Leitzinger Oy (5I4) Method and machine for the production of network metal - Förfarande och maskin för framställning av nätmetall

The invention relates to a method for producing a mesh metal by first forming a blank, i.e. a workpiece, from an extrudable metal by an extrusion process such that it has two relatively thin ribs at its edges, the web connecting these strands between adjacent strips is formed by piercing rows of holes so that the holes in each row of holes are stepped relative to the holes in the adjacent row, and then the chucks are gripped and pulled apart to increase the width of the workpiece as its length decreases and the chords bend.

The invention also relates to a machine for producing a network metal.

In previous methods of manufacturing truss-like metal objects, it has been essential that the edge fringes have remained rigid, as a result of which the oblique parts of the net between them have been formed * 3 8 7 Λ 2 mainly by stretching, whereby the bending rate has been relatively small. However, there are many applications that do not require a metal object such as a truss beam, but instead a reticulated object that does not need to have rigid edge beams. In the manufacture of such products, their length decreases substantially while their width substantially increases, forming a reticulated object. In this way, the net is mainly made by bending its material.

There are a number of different methods for making a net by stretching, but these have experienced difficulties when there are a large number of openings in the net when stretching, due to the fact that each point of the net must be stretched evenly. This has resulted in a costly waste of time placing the blank, i.e. the workpiece, on its supporting organs.

It has also been suggested in the past, for example in DE 2 341 886, that the workpiece is gripped by means of jaws at the edge girder, after which the jaws are pulled away from one another.

The disadvantage of this procedure is the very uneven stresses on the workpiece, because the parts of the workpiece adjacent to the gripping points generate stresses not only in the direction of movement of the jaws but also in the transverse direction. This is a necessary consequence of the fact that in the gripping area the length of the workpiece remains unchanged, whereas between the pairs of jaws in the middle of the workpiece the length decreases.

The object of the invention is to provide a method similar to that mentioned at the outset, which enables the rapid formation of mesh metal and at the same time ensures that the workpiece is subjected to uniform stresses when it is stretched.

According to the invention, this is achieved by gripping the part close to the web behind the chords only slightly frictionally. The jaws do not adhere firmly to the chord or web, but leave a sufficient distance so that the chin can bend and the web between the jaws can slide transversely to the longitudinal centerline of the workpiece. Because the jaws grip the workpiece close to the web, no curvature can occur in the vertical plane, so the chords can bend without waving, wavy as the length of the workpiece decreases. In some cases, the chords are intended to remain part of the product, so that they do not have to be as thin as in cases where the chords are removed after the product has been manufactured. In the latter case, the loss of metallic material due to the removal of the corrugated chords is lower in cost than the additional cost due to the slowness of the hitherto known methods, which is caused e.g. that in hitherto known methods each row of holes has had to be stretched separately and the workpiece then placed on hooks. In addition, in the method according to the present invention, the cut-off edge metal can be returned to the process in the case of an extrudable metal, as a result of which the extrudable metal is particularly well suited to the method according to the invention.

As mentioned above, the invention also relates to a machine for applying the method of manufacturing a net according to the invention.

Australian Patent Application 58,914 / 73 to Comalco (J. & S.) Pty. Ltd. a machine is described which is suitable for use in making a net by stretching a blank, i.e. a workpiece.

This machine is very suitable for large-scale production and can be used to make a net by stretching, which reduces the length of the blank and increases the width. The machine is also suitable for making oblique spacers of a beam by stretching, whereby the edge chords remain deformed with respect to length but the oblique spacers are stretched, resulting in a reticulated web structure. The machine according to the present invention can also be used for these purposes, but the machine according to the present invention is very much cheaper to purchase than the machine disclosed in the above-mentioned publication. In addition, the machine according to the present invention is very suitable for small production series, because the machine can be quickly and easily changed to produce a network of a different quality with very low installation costs due to the modification work.

The net stretching machine according to the present invention has two 4 6 3 Ω 7 longitudinal sets of jaws formed in pairs with respect to each other, almost list-like flanges, one of which is displaceable with respect to the other, and means for effecting this displacement.

Furthermore, it is very advantageous if the distance of the straight or preferably convex inner surfaces of the jaws facing each other from the corresponding surfaces of the respective second pair of jaws is greatest at the gap between the jaws. In this case, the blank, i.e. the workpiece with thin chucks, is easily bent into a corrugation, whereby it can at the same time easily move between the pairs of jaws as its length shortens. In addition, at the same time, the deformation of the intermediate parts into a beam-like body is facilitated because the chord is not subjected to a load during the deformation except for that caused by the location of the central web. In addition, the use of channel frames makes it possible to use sliders with hooks attached for stretching the net in cases where the use of hooks is absolutely necessary.

An embodiment of the invention is described in more detail below with reference to the accompanying drawings, in which:

Figure 1 shows a top view of a stretching machine.

Figure 2 shows the same seen from the side.

Figure 3 shows a perspective view of the blank, i.e. the workpiece, after forming the holes or before stretching.

Figure 4 shows the blank after stretching.

Figure 5 shows on a larger scale a section of one pair of jaws.

Figure 6 is a perspective view of a hook that is occasionally used to stretch a blank.

5 6 3 8 7 Λ

Figure 7 is a side view of the hook forming part of the machine.

In this embodiment, the stretching machine 10 is provided with a fixed base body 11 having a channel frame 12 comprising two jaws 13 attached to the fixed base body 11 on one side thereof, the movable base body 15 being on the other side of the longitudinal center plane of the machine. The movable base body 15 has a second channel body 12 similar to the first.

Each duct body 12 has two duct members 17 (FIG.

5) having interconnected horizontal webs 18 and chords 19, wherein the lower chutes of the channel member are directed upwards and the upper channel member downwards, and wherein the channel members 17 are spaced apart by adjusting bolts 20 and locking bolts 21, the latter having locking nuts 22 In this way it is possible to adjust the distance 23 of the chutes 19 facing each other in each duct body. The chutes 19 of each duct body, which are closest to the longitudinal center plane of the machine, are lined on their inner surfaces with low friction nylon strips 24 directed inwards towards the center of the duct body. 26 a thin cross-section chord 25 is pressed against the inner surfaces of the channel body chords 19 and the blank chord 26 is between its edges, the support point of the chin jaws 19 is close to the blank web 26. This limits the vertical movement of the workpiece chord 25. and greatly facilitates the bending of the chords 25 in a horizontal plane (as can be seen from Figure 4) when the chamfered strips 27 of the blank are bent so as to form a reticulated structure.

The movable base body 15 is connected to the fixed base body 11 via a plurality of hydraulic cylinders 29 driven by a pump 30 which move the movable base body 15 away from the fixed base body 11 to provide the necessary mesh stretching (or beam formation if used).

Sometimes the net is made of a blank without chords 25 or of a blank with chords

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difficult to deform. In this case, there is a greater degree of deflection of the diagonal supports and a smaller amount of elongation than in the case where a beam with rigid and inflexible edge beams would have to be produced (the beam is not shown in the figures). To facilitate the support of such a net and at the same time allow the length to be reduced therein, each channel body may be provided with a plurality of sliding hooks 34 as shown in Figure 6. Each sliding hook 34 has a central web 35 located in the slot 23 and terminating in a flange 36 with a sliding outer surface 37 on the strips 24 on the inner surface of the channel of the duct body. At the outer end of each slide hook 34 there is a hook portion 3Θ which engages the slot 39 in the blank (Fig. 3) to provide the necessary grip.

To facilitate handling of the blanks, the machine 10 has a chain 44 with a hook 45 interposed between the two channel frames 12 (Fig. 7), the chain being connected to the drive so that before stretching the hook fits into the slot 39 in the blank and the chain is used to pull the blank into the machine. , that the edges of the blank are adhered to the palate jaws 19 (either by the jambs 25 or by means of sliding hooks 34 depending on the method used). The hook is mounted on the chain 44 and connected to it by a spring 36 so that moving the chain in the opposite direction detaches the hook for a moment before stretching occurs.

The chain can also be used to remove the workpiece. To handle workpieces of different sizes (except in cases where sliding hooks 34 are used), the only adjustment required is the adjustment of the spacing of the chutes of each channel body, and in many cases it is not even necessary to perform this. The blank is moved, stretched and the finished product removed very quickly. If several blanks have to be stretched or bent in the same way, this is achieved by moving the channel bodies 12 apart until the movable body contacts the adjustable stop screws 48 which are suitably adjusted.

In the embodiment described herein, the preform shown in Figures 3 and 4 is extruded aluminum or aluminum alloy with a central web 26 having a plurality of spaced apart and longitudinal brace-like strips 27 and relatively thin chords 25 at its edges. . The web 26 joins the chord 25 at the center of the edge of the chord, as a result of which the extruded product is symmetrical with respect to its two transverse axes perpendicular to each other.

A plurality of slots 39 are then formed in the webs between the slats and in the web between the edge pairs and the adjacent slats so that each row of slots is staggered relative to the adjacent slit row, and adjacent slit rows are arranged in an overlapping position relative to each other. The blank is then placed in a stretching machine 10. The chords are relatively thin, and as the gripping members pull the chutes of the blank away from each other, the length of the blank to be treated decreases and the chords bend outwardly as described above. In many cases, the bent chords have to be cut off and this is done in a manner known per se, for example in this case with a cutter.

According to another embodiment of the invention, the edge ribs 25 remain part of the final product and are not cut off after the product is finished. The edge pair on the other side of the product may have the shape of the edge pair on the opposite side, so that when the two products are placed side by side, their chords can be fastened to each other.

According to the present invention, it is possible to produce a network with a number of relatively small openings at a very low cost. Even in the case of large openings, the manufacturing speed is so high that the manufacturing cost is relatively low, in addition to which the metal removed from the edges of the product has a scrap value because it can be recycled.

Claims (3)

8 6 3 8 7 4 A method of making a mesh metal by first forming a blank, i.e. a workpiece, from an extrudable metal by an extrusion process such that it has two relatively thin ribs (25) at its edges, the web (26) connecting these struts having a plurality of spaced, parallel and parallel thick ribbed strips (27), then formed between adjacent strips (27) in the web (26) by piercing rows of holes (39) so that the holes in each row of holes are stepped with respect to the holes in its adjacent row :, and then the chords (25) are gripped ) and are pulled apart to increase the width of the workpiece as its length decreases and the chords (25) bend in a wavy manner, characterized in that the part close to the web is gripped only slightly frictionally behind the chords (25). A machine for producing mesh metal according to claim 1, wherein the machine has two longitudinal pairs of jaws (13) of nearly planar flanges directed in pairs relative to each other, one of which is displaceable relative to the other, and means (29, 30) for providing this displacement, that each set of jaws (13) comprises a device for keeping the girders (19) facing each other at a certain distance from each other, the inner surfaces of the girders (19) of the pair of jaws (13) facing each other adhering to the workpiece chord (25) being coated with strips of such material, with a low coefficient of friction. Machine according to Claim 2, characterized in that the distance between the straight or most suitably convex inner surfaces of the jaws (13) facing the jaw pair (13) and the corresponding surfaces of the respective second jaw pair is greatest at the gap (23) between the jaws (19).