AU604987B2 - Means and method for expanding slotted materials - Google Patents

Description

K

1

I

-JI'111 (1 (Th~ Form COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-62 COMPLETE SPECIFRCATION

(ORIGINAL)

FOR OFFICE JSE: Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Class Int. Class 0 as This document contains the amnendments ma~de under Section 49 and is correct for Printing.

Name of Appioanth Address of Applicant: 0. 0., TO BE COMPLETEC- BY APPLICANT HAROLD REX JURY 22 Provtidoent Avenue, Glynd.e, State of South Australia,, Comimonwealth of Australia Act.al lbventor: HAROLD RJ X JURY A .1 Add rcss for Service: Care of R.9. MADDERN ASSOCIATES, 345 King William Street, Adelaide, State of South Australia, Commonwealth of Australia Complete Specification for the Invention entitled, "MEANS AND METHOD FOR EXPANDINjG 5XJOTTED MATERIALS" The following statement Is a full description of this Invention, Including the best method of performing It known to me.

A0O074E8 pokET. TRAUE MAiY ~IRlCE 0 0 a4*4 a v 2 0 4 4 4 4 U; 4 4 4 This invention relates to a meais of and method s\oLfe_ for expandings .oid material and is applicable for expansion of various types of material, including roll formed steel, extruded aluminium and other materials which can be produced in lengths having constant cross sectional shapes which include ribs joined by webs. The invention is particularly applicable to metal but can also be applied to certain plastic alloys which are capable of being formed and retaining their deformed shape.

Expanded slotted material is old and well known, and for example the Applicant herein was the inventor in the matter of Australian Patent No. 500092 ("7894/76) and other earlier Patents, all relating to the expansion of slotted material.

A number of problems are encountered however with the expansion of slotted material, firstly in that if continuous jaws are used, there is frequently too much friction to effectively expand the material, and the friction will result in the edges gripped by the jaws preventing inward movement of the ends as the width is increased, and this in turn wikl result in an inward waisting of the sheet. The result of this in turn is that there is a large degree of wastage.

To overcome this problem, in a second invention of the Applicant the material was expanded by placing hooks through all of the slots along the two edges, but 2 1 -I-I *Wit Sft 6 04 S C 4*e S

S

S

p 0 t f 4 this was so slow and awkward to perform that the method was finally abandoned.

A number of different methods have been developed for the stretching of mesh, but difficulties are encountered when there are a large number of apertures in the member to be stretched, in that it is necessary for each element to be stretched equally, and the time When the workpiece has a plurality of ribs separated by webs and the webs contain slots staggered in alternate rows, and the workpiece is expanded, the webs join to adjacent ribs and form stiff areas in the expanded workpiece so that the ribs between the webs bend mostly at the locality of the webs. This has the effect of assisting the workpiece to be expanded with some degree of uniformity, but the outermost ribs are not so supported and for that reason the aforementioned Patent 500092 utilised thin flanges for their outermost ribs.

The jaws of a stretching machine contacted the facing surfaces of the thin flanges only adjacent their intersections by the respective webs, and the jaws did not grip the flanges or web but remained separate by an amount sufficient to enable the flanges to buckle, and the web to slide between the jaws towards the longitudinal centre of the workpiece. Although the flanges were thin they assisted in the formation of a regular pattern mesh, and were subsequently guillotined from the workpiece and discarded.

3 Although the metal could often be recycled (for example if it is aluminium) nevertheless the scrap value was much less than the metal value in extrusions and the wastage was high and the material handling problems were such that considerable labour is required to package and return the metal for recycling.

In an embodiment of this invention the outermost o44A 4*"o webs of a workpiece are positioned between spaced jaws of two respective pairs of jaws and the jaws are 10. separated with the outermost ribs in abutment with 0 4o surfaces of the jaw so as to expand but decrease the length of the workpiece which, after expansion, is *removed from the jaws.

go°4 There is of course the same tendency for random 15. buckling of the outermost ribs which otherwise occurs with the outermost flanges described in aforesaid Patent oo 500092, but if the outermost ribs are not in the form of thin flanges but nevertheless have their minimum section modulus lying in the plane of the workpiece which includes the ribs and webs, in most instances the buckling of the outermost ribs occurs centrally between the interesections of the rib and web provided the ratio of rib cross-sectional area to such section modulus is relatively high.

-4left oil t off 44 t 6 t a

A

4 0.4 6 4 6 t 6 t 2 0 One of the cross sectional shapes which is used in this invention is a generally diamond shape wherein the walls of the ribs slope towards each other from the webs both above and below the webs, and it should be noted that the section modulus in -the plane of bending such a shape is only half that of bending the same shape if it is in a square configuration with respect to the workpiece plane.

In some instances however there is a requirement for lightweight extrusions and the most effective cross sectional shape for the ribs is a cruciform shape, wherein the ratio of cross sectional area to section modulus in the aforesaid plane is small, that is, a buckling of the outermost ribs is difficult to achieve, and in such instances the invention contemplates notching the inner edges of those outermost ribs between the intersection with the webs so that the ribs buckle at the notches.

When solid metal is expanded in accordance with aforesaid Patent 500092, thore is a "waisting-in" of the ends of the mesh because this corresponds to the minimum deflection of the ribsi, and consequently the methods presently used include the formation of very long mesh panels wherein the waist-in ends are discarded (sometimes as much as 300ml each end) and the long panel is guillotined into several shorter panels, for example 5 for use as screen door or reinforcement panels. This involves several guilloting operations, further wastage of material, further material handling problems, the use of very long workpieces which are difficult to handle, and the use of very long stretching machines which are, by this invention, an unnecessary expense.

One of the objects of this invention is to limit the end wastage and in an embodiment of the invention a mesh shape stabiliser is applied to the workpiece near its 9.

10. ends and has a force applied against those ends during 00 the expansion of the mesh to inhibit mesh distortion to a oo sufficient degree that the mesh ends do not require further trimming, and thereby it becomes unnecessary to have the very long workpiece for stretching which has S* 15. been previously used and to have the subsequent 0: guillotining and wastage which presently occurs by employing the method of Patent 500092. The mesh shape Ssubsequently can, for example, be a telescopic bar having friction pads thereon which resist the inward waisting of 0 the mesh ends, by engaging in the end holes at the centre of the workpiece, but preferably the stabiliser comprises a pneumatic piston/cylinder assembly wherein the pressure can be more accurately determined. Alternatively, or additionally, the force may be applied to the ends adjacent the jaws to assist the ends in their initial movement towards one another at the locality of the jaws 6 i during the expansion operation.

An embodiment of the invention is described hereunder in some detail with reference to and is illustrated in the accompanying drawings in which: Fig. 1 illustrates a configuration wherein a mesh shape stabiliser is located intermediate the sides of the workpiece, and wherein the workpiece is so short that 'ce within the stabiliser it would not be possible to achieve 9 C a regular mesh pattern, S 10. Fig. 2a shows diagramatically the way in which the o T stabiliser effectively reduces the width of the workpiece ti into two half widths and thereby places a series of aligned rib portions into compression during the 4 *1 «o expansion, Fig. 2b illustrates an elongate workpiece showing S how the increased number of aligned chords between the sides will reduce distortion and thereby stabilise the mesh shape, Fig. 3 is a side elevation which shows the position of the mesh shape stabiliser prior to expanding the mesh.

Fig. 4 is a diagrammatic plan view of a mesh expanding machine (which in itself does not embody features of the invention), 7 L i i Fig. 5 shows a cross section through one pair of jaws as used in the expansion of a workpiece having its ribs in a diamond configuration, Fig. 6 is a plan view illustrating the expansion of the mesh wherein the mesh shape stabiliser comprises a plurality of pressure actuated piston/cylinder assemblies coupled to the ends of the workpiece adjacent the jaws by cables which pass over pulleys at the ends of the jaws to engage the other ends of the workpiece, Fig. 6 showing l,0 the section plan of Fig. SFig. 7 is a fragmentary section showing portion of a lightweight mesh panel wherein the ribs have a cruciform cross sectional shape and have a relatively small area to section modulus ratio, and Fig. 8 illu trates the manner in which the outermost o0.4.: ribs may be punched to have notches intermediate their ends to reduce section modulus at those points and improve the buckling characteristics on those outermost 0 ribs.

Reference is first made to Figs. 1, 2 and 3. In Fig. 1 a very short workpiece 10 is to be expanded to a mesh which has a greater width but shorter length than the slotted workpiece, and is shown by the dotted lines 11, the workpiece of Fig. 1 is so short that there is no continuous alignment of rib portions which would resist compression upon mesh expansion so that a regular 8 i L L -l 71 pattern would not be possible to achieve without the use of a mesh shape stabiliser 12. If an attempt is made to stretch the mesh without such a stabiliser, the pattern shape is random and irregular and there is extensive waisting-in of the ends of the mesh. Fig.

2a illustrates the manner in which the stabiliser 12 effectively divides the workpiece 10 into two halves, iand in one diagonal direction there are four groups of aligned rib portions 13 while in the other direction •there are three such groups, and the extensive distortion and waisting-in will then occur only in the end triangles T, so that the overall shape of the mesh panel illustrated in Fig. 1 will be very much improved.

I

1 In order to more clearly explain this phenomenon

I

g: which has not been previously recognised, Figs. 2a and 2b t o, show expanding short panels, much shorter than would be used in production even by the employment of this invention. Fig. 2b illustrates a more usual arrangement t, wherein the heavy lines 14 illustrate the maximum compression resisting rib portions in a longer workpiece and the relatively small triangular portions T in which distortion would occur. Fig. 3 illustrates a workpiece 10 in its slotted but not in its expanded state, and shows the way in which respective projections 15 of the piston and cylinder of stabiliser 12 are positioned in slots 16q These bear against the unslotted portions 17 of the workpiece webs 28 and reduce the "waisting-in" 9

MMMMM

by the ratio of between 5 and 10 to 1 depending upon the workpiece. Fig. 4 illustrates an expanding machine 21 which comprises two pairs of fixed spaced jaws 22 which are movable apart by means of an hydraulic cylinder 23.

This machine is generally similar to the machine described in the expired Jury Spiers patent 434936, and can have hinged jaws to facilitate loading. Figs. and 6 illustrate the workpiece 10 having a configuration wherein the ribs 24 are stretched in a diamond mode 10. because of the relatively small section modulus in the o o* plane p-p of the ribs and webs, in relation to the rib cross-sectional area. In such an instance it is not necessary to notch the outermost rib 24, as is done in another embodiment described below wherein the ribs have 08 S* 15. a relatively large section modulus to area ratio.

0. In Figs. 5 and 6 expanding machine 21 is provided with two piston cylinder assemblies 25 attached to the outer wall of the respective jaws 22, and these are coupled to cables 26 which pass over end pulleys 27, and a method of stretching comprises coupling the piston/ cylinder assemblies to the workpiece by passing the cables 26 around the pulleys 27, crossing the cables and hooking the free end of each cable with hooks 28 to the workpiece near its other end from the pulley over which the cable passes. (The hooks 28 are required to resist tension, unlike the projections 15 which are required to resist compression.) 10 As an alternative to the pulley and cable arrangement of Fig. 6, stabilisers similar to the stabiliser 12 of Fig. 1 can be hand positioned near the edges of the workpiece and adjacent the jaws, but whereas the stabiliser 12 has fluid at pressure against the back of the piston (not shown) to resist contraction, the air pressure would be applied to the piston rod ends of the cylinders when adjacent the jaws to assist contraction.

9 Each method however is quick and efficient and most St 4, 10. effective.

9 t «As said above, the most efficient cross-sectional shape for a lightweight panel is a cruciform shape as shown in Fig. 7, which illustrates an extruded workpiece 6 31 wherein each rib has flanges 32 directed in four 15. directions. Because the section modulus to cross- *99* sectional area ratio of these ribs 33 is much higher than the ratio in Fig. 5, there is a danger of the outermost rib 33 buckling in a random manner and this is guarded against by notching the outermost ribs 33 at 34.

5 It may be noted that the slots 35 are best produced for this invention by a punching and not a roll cutting operation.

It is not necessary to give initial deformation to the outermost ribs 33 as shown in Fig. 8, but in some instances this can assist in achieving the initial buckling of the outermost ribs 33, and then deformation is easily achieved during the punching operation by ii merely having a wedge surfaces on the outermost punches.

In both embodiments, a workpiece 10 is slotted to the general configuration illustrated in Fig. 8 (but not necessary with notches 34) and is drawn into the jaws 22 and the expanding mesh. One or more mesh shape stabilisers 12 are positioned on the workpiece as shown in Fig. 1, or if the cable arrangement of Fig. 6 is used, the cables are hooked into the workpiece, in all cases ,o 1 S air pressure being applied to the cylinders of the .o9> 10. relevant stabiliser piston/cylinder assemblies to apply 0 00 Co a0 force to the workpiece ends. The workpiece is then 0o ,o expanded against stops 38, the pressure air removal from the shape stabiliser, the hydraulic cylinder reversing a o4 99 little to allow the expanded mesh to relax, and the 9 99

S

s 415. workpieco is drawn (or lifted) outwardly away from the •49o90 jaws 22 avid be replaced by a second workpiece.

°,000 An advantage of this invention is that the punching 0 0 °2 and expanding can take place in the same duty cycle and 040 lb 0, thereby the equipment required can occupy a small factory 0 9 space.

It is unneolsary to trim the sides or ends of the workpiece since satisfactory mesh formation can be achieved by utilisation of the mesh shape stabilisers and a selection of suitable shapes for the outermost beads.

The workpieco can be cut to length before slotting and the length after expansion can be accurately gauged by 12 4 a, I~4E *4 4 a aa#~ 4 4 4 #4 a 44 4 44 aa a a 44 4 4 *4 #44441 4 I

S

#4*441 a s o 44 4 444 1 4 *4 44 a dahermining the degree of expansion. The: motho is niot limited to extrusile material as previous methods have been but can be applied for example to hot rolled steel or to those plastic alloys which can retain an expanded shape. since short workpieces can be expanded with this method, they can be immediately packed after the expansion operation arid there is no requirement for extensive material handling as in my atoresaidi prior art invention.

-13

Claims (10)

1. A method of expanding a workpiece having a plurality of parallel ribs spaced by joining webs, wherein each web has a row of slots therein which are staggered with respect to slots in each adjacent web, comprising positioning the outermost webs of the workpiece between spaced jaws of each of two respective pairs of jaws, attaching a mesh shape stabiliser to the workpiece near its ends and applying a force against those ends to inhibit mesh distortion during said workpiece width 0 I c expansion, separating the jaw pairs with the outermost ribs o« in abutment with surfaces of the jaws so as to expand the o ,c width but decrease the length of the workpiece, and o removing the thus expanded workpiece frop the jaws. *9 8

2. A method according to claim 1 wherein said mesh shape stabiliser comprises pressure actuated piston/cylinder assemblies associated with each respective said pair of laws, b* coupling those assemblies to the workpiece at positions adjacent the jaws and, near the workpiece eids, and applying 20 pressure to the cylinders of those assemblies to draw Lhe ends of the workpiece adjacent the jaws towards each other I* while effecting said expansion,

3. A method according to claim 1 wherein there is a pair of said pressure actuated piston/cylit, assemblies adjacent each respective said pair of jaws, a pair of pulleys at the respective ends of each said pair of assemblies, and cables coupled to movable portions of the piston cylinder assemblies, 14 the method comprising effecting said coupling of those assemblies to the workpiece by passing the cables over respective pulleys, crossing the cables, and hooking the free end of each cable to the workpiece near the other end thereof from the pulley over which that cable passes.

4. A method according to claim 1 wherein the mesh stabiliser comprises a pneumatically actuated piston/cylinder assembly and respective workpiece engagement projections coupled to the piston and to the cylinder of the assembly, o 0 the method comprising inserting respective said 0* a projections into respective said workpiece apertures near the ,ooogQ end of the workpiece and between its said outermost ribs, and 0 Q S, applying air at pressure to the assembly to exert a separating force to the workpiece ends of sufficient magnitude to reduce waisting-in of the ends of the workpiece .C0 during expansion. o*

5. A method according to claim 1 wherein the mesh stabiliser comprises a plurality of pneumatically operated piston/cylinder assemblies, and means securing the cylinder of each assembly with respect to a said jaw, 00 the method comprising coupling the piston of each assembly to an end of the workpiece and between said outermost ribs, and applying air at pressure to the assembly to inhibit waisting inward movement of the ends of the workpiece during expansion.

6. A metho according to any preceding claim further comprising positioning the workpice between the jaws by applying a force to the workpiece with a winch to slide the 15 workpiece endways with its outermost webs between the jaws of respective jaws.

7. A method according to any preceding claim further comprising removing the expanded workpiece endways from between the jaws by applying a force to the expanded workpiece to slide the expanded workpiace endways from the jaws.

8, A method according to any preceding claim comprising punching said rows of slots in the outermost webs 11Q with notches in the webs intermediate the slot ends which reduce the section modulus of the outermost ribs where those ribs are to be bent upon said expansion of the workpiece. t* ,t

9. A method according to any preceding claim comprising punching said rows of slots in the webs to be of sufficient width that the minimum section modulus of each rib is in a central plane of the ribs and webs. *e 'r

10. A method of expanding a workpiece substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. Dated this 25th day of September 1990. HAROLD REX JURY By his Patent Attorneys, R K MADDERN ASSOCIATES f t 16 16 f j