US3740812A

US3740812A - Method of making expanded metal products

Info

Publication number: US3740812A
Application number: US00172763A
Authority: US
Inventors: T Ryan
Original assignee: JURY AND SPIERS Pty Ltd
Current assignee: JURY AND SPIERS Pty Ltd
Priority date: 1970-08-24
Filing date: 1971-08-18
Publication date: 1973-06-26
Anticipated expiration: 1990-06-26
Also published as: CA952282A; DE2142088A1; GB1356278A; FR2105960A5; ZA715526B; JPS527264B1

Abstract

A post comprising a series of struts radiating outwardly from a central portion produced by a method of firstly extruding ductile metal to a constant cross-sectional shape which includes a central portion and at least three circumferentially spaced webs, punching a plurality of rows of slots in each web, arranging the lengths of the slots to be great compared with the distance between them and arranging the slots to be staggered, then stretching the metal between the slots of the rows so as to form a series of struts, the unpierced metal of the product constituting the chords of the trusses so formed.

Description

[ June 26, 1973 METHOD OF MAKING-EXPANDED METAL PRODUCTS [75] Inventor: Trevor B. Ryan, Rose Park,

Australia [73] Assignee: Jury & Spiers Proprietary Limited,

Norwood, Australia 22 Filed: Aug. 18,1971

21 Appl.No.: 172,763

[30] Foreign Application Priority Data Aug. 24, 1970 Australia PA2297/7O [52] US. Cl 29/155 C, 29/6.l, 52/635 [51] Int. Cl 1323p 17/00 [58] Field of Search 52/634-637, 730, 732,692, 696, 670, 672; 29/6. 1 I55 [56] References Cited UNITED STATES PATENTS 1,927,442 9/1933 Laufle 52/635 3,034,197 5/1962 Watawabe 521635 X FOREIGN PATENTS OR APPLICATIONS 16,187 898 Great Britain 52/670 508,719 920 France r 52/635 485,923 970 Switzerland 52/730 Primary Examiner-Thomas H. Eager Attorney-Oldham & Oldham [57] ABSTRACT A post comprising a series of struts radiating outwardly from a central portion produced by a method of firstly extruding ductile metal to a constant cross-sectional shape which includes a central portion and at least three circumferentially spaced webs, punching a plurality of rows of slots in each web, arranging the lengths of the slots to be great compared with the distance between them and arranging the slots to be staggered, then stretching the metal between the slots of the rows so as to form a series of struts, the unpierced metal of the product constituting the chords of the trusses so formed.

6 Claims, 8 Drawing Figures IPAIENIEDJUNZBIBH SHEEP 1 0F 7 (QM M 9 @M PAIENTED M25 3. 740. 812

SHEET'S 0F 3 METHOD OF MAKING EXPANDED METAL PRODUCTS This invention relates to a method of forming a metal product initially to a contracted dimension and subsequently expanded so as to include a plurality of struts, thereby interconnecting chords to form a truss.

Heretofore, trusses have been formed by the process of welding struts between chords, but this process is slow and expensive. Furthermore the appearance of the trusses formed by this process is not aesthetically pleasing. Consequently, in such applications as street lamp posts, telegraph posts and the like, trusses are not favoured and in many instances composite steel and concrete members, or tubular members are used. In both cases, however, the cost is considerably higher than a simple truss, even if that truss is'of welded construction. One of the objects of this invention is to provide an expanded metal product which can be utilised as a post, and wherein the cost will be less than, say, a tubular post of the same strength, or a similar welded truss, and which will at the same time be more pleasing aesthetically.

A product formed by the method of this invention consists of an expanded metal product having a central portion, at least three circumferentially spaced trusses radiating outwardly from the central portion, said central portion forming one chord of each respective truss, an outer portion on each respective truss forming another chord thereof, and struts interconnecting the chords of the trusses and being inclined thereto, the trusses comprising a single integral member of ductile metal, and the metal contained within the struts being in a condition of having been strained beyond its yield point by stretching.

According to the invention, the method an expanded metal product comprises:

a. extruding ductile metal to form an extruded prodof forming uct having a constant cross-sectional shape which includes a central portion with at least three circumferentially spaced webs radiating outwardly therefrom, each web terminating at its outer end in an outer portion, and each web having a rib extending along it, each rib being between the outer portion and the central portion,

b. removing metal from each web so as to form a row of slots on each side of the rib thereof, the length of each slot exceeding twice the length of metal remaining between either one of its ends and the adjacent end of the next slot in the same row, and the slots of a row on one side of the rib being staggered relative to those of the row on the other side so as to form therib into a plurality of strut-forming portions, and

c. forcing respective said outer portions away from the central portion to thereby incline the strut-forming portions of the ribs relative both to the respectiveouter portions and to the central portion and at the same time elongate the metal thereof by stretching it, thus form-- ing struts joining respective outer portions and the central portion so as to in turn form trusses, the chords of which are constituted by said central portion and re-v spective said outer portions.

With this arrangement it becomes possible to construct a post which is very pleasing in appearance and which has inbuilt conduit means. If a plurality of tubular members are utilised (either in the centralor outer portions), the post can be, for example, divided into 2. two, three or more branches at its top end, and utilised for supporting street lamps, wiring or the like.

Embodiments of the invention are described hereunder in some detail with reference to and are illustrated in the accompanying drawings, in which:

FIG. 1 is an elevational view of a post,

FIG. 2 is a section through an extruded metal product which has a constant cross-sectional shape, illustrating the first stage of producing the post,

FIG.- 3 is a fragmentary elevation showing the product of FIG. 2 but with metal removed from the web,

FIG. 4 is-a diagrammatic section showing stretching of the strut-forming portions of the ribs of the product illustratedin FIG. 3,

FIG. 5 is a fragmentary elevation similar to that of FIG. 2 but showing (to a large scale) the configuration of the struts after stretching,

FIG. 6 is a diagrammatic plan view illustrating the means for andmethod of forcing outer portions away from the central portion to stretch the strut-forming portions of the ribs and thus form them into struts,

FIG. 7 is an elevation of a post according to a second embodiment, and

FIG. 8 is a section through an extruded metal product which may be used for producing a post as illustrated in FIG. 7.

Referring first to the embodiment which is illustrated in FIGS. 1 to 6 inclusive, the expanded metal product formed by the invention is the post 10 illustrated in FIG. 1. Such a postis useful for the supporting-,ofoverhead power lines and the like. The post 10 comprises acentral portion -11 which can be seen in section in FIGS. 2 and 4 and'which is a tubular member, four trusses 12 which radiate outwardly from the central portion 11, the central portion 11 forming one chord of each respective truss, and an outer flange 14 forming the other chord thereof, and a series of struts designated 15 interconnecting the chords of the trusses and being inclined thereto, the trusses comprising a single integral member of ductile metal, and the metal contained within the struts 15 being in a condition of having been strained beyond its yield point by stretching of metal to form the struts 15.

The first stage in the production of the product of FIG. 1 is extrusion of a metal product designated 17 and illustrated in section in FIG. 2. The metal of the product 17 is essentially a ductile metal since it needs to pass through a subsequent stretching operation for the formation of the struts l5, and a large number of aluminium alloys are found to be suitable for use within this invention. The invention can however be used with other extrusile metals which also have ductile properties. The required degree of ductility of course is determinedby the required degree of stretch of the strut forming portions, which, after stretching, form the struts 15. The metal product 17, in being extruded, is of constant cross-sectional shape, and has the central portion 11 of tubular shape as described above, and a series of four webs l9 radiate outwardly from the central portion 11 to terminate at their outer ends in the outer flanges 14. Each web 19 has in it a pair of ribs 20, the ribs 20 being between a respective flange 14 and the central portion 11.

FIG. 3 illustrates a further step in the formation of the expanded metal product, wherein metal is removed from each of the webs 19 to form three rows of slots designated 22, the length of each slot exceeding twice the length of the metal designated 23 which remains between the ends of the slots and the adjacent end of the next slot in the same row, and as shown in FIG. 3 the slots of any one row on one side of a ribv 20 are staggered relative to the slots of the row on the other side of that rib so as to form the rib into a plurality of strutforming portions which are designated 24. (The lengths of the portions 24 are normally much greater than shown in FIG. 3, wherein the slots 22 are shown to be short in length so that the principles of the invention may be more clearly illustrated.) It may be noted that in this embodiment the width of the slots 22 is the same as the space between the ribs, or between a rib and the central portion or between a rib and the flange as the case may be, since this enables a simple punching operation to take place wherein the central portion, the ribs and the flanges themselves form the back-up die for a punch, and a male punch only is required. In the alternative, if the slots are formed by a roll punching operation, the back-up roller does not need to have slots therein to function as the female die. This simple expedient is another advantage of this invention.

FIG. 4 illustrates diagrammatically a section through stretching jaws, which are carried on the ends of pivoted clamping bars 28, and as shown in FIG. 6, the clamping bars 28 are arranged to be clamped by respective pressure clamping cylinders 29'. As shown in FIG. 6, the stretching jaws 27 on the left-hand side of the drawing are fixed, but those on the right-hand side are coupled to stretching cylinders 31 which are independently operated to provide either a parallel or a tapered post 10. In this embodiment the tapered post 10 is shown being produced by greater movement of the lower stretching cylinder 31 than the upper stretching cylinder 31. Upon operation of the stretching cylinders 31, two opposite flanges 14 are forced away simultaneously from the central portion 11, and this performs a double function on the strut-forming portions 24 of the extruded and slotted member which is illustrated in FIG. 3. The strut-forming portions are inclined relative to the outer flanges l4 and the central portion 11, and simultaneously they are elongated by a process of stretching, and this action forms the struts 15 from the strut-forming portions 24, in turn forming the trusses 12 which haveas their chords the central portion 11 and the outer flanges 14.

The post 10 which is formed by this method and in accordance with this invention is pleasing in appearance, and contains an inbuilt conduit for protection of electrical cables, the central portion 11 of course functioning in this manner. The post is considerably stronger than other posts of the same material and similar cost, andif the number of trusses is less than five then the punching and stretching operation is easily .effected. The ideal number of trusses isxfour as illustrated, since this enables two trusses to be formed simultaneously in one stretching operation, and also enables two webs to be punched in onepunching operation. Punching of course is rendered more difficultif the number of trusses is increased.

FIGS. 7 and 8 illustrate respectively a'post and a section through the extrudedmetal product from which it is made in accordance with a second embodiment. The post 35 illustrated in FIG. 7 is provided with two tubular portions 36 which form part of the central portion 11 of the post, the tubular portions 36 being bent over to form two goose-neck lamp supports at the upper end of the post ;as-illustrated in-FIG. 7. The webs 37 each contain only one rib 38: between the central portion 11 and the outer flanges 14. Each web 37 is punched with a row of slots on each side of its rib 38, the slots overlapping as described aforesaid, and each truss designated 39 in FIG. 7 has only one series of struts 40, as compared with two series of struts in the first'embodiment. Such a post is lower in cost but slightly less rigid than the post illustrated in the first embodiment. Y

If'the invention. is utilised with an extrusion of suitable cross-sectional -shape, it will be seen that the flanges may themselves be tubular in section, this arrangement having the advantage of more rigidity than the posts which are illustrated in the above embodiments. I

With the appropriate cross-sectional shape of extruded product, an expanded metal product can be formed which is useful as a beam, and for example may be used in situations where strength is required in more than one plane.

What I claim is:

1. The method of producing an expanded metal product comprising:

a. extruding ductile metal to form an extruded product having a constant cross-sectional shape which includes a centralportion with at least three circumferentially spaced webs radiating outwardly therefrom, each web terminating at its outer end in an outer portion, and each web having a rib extending along it, each rib being between the outer portion and the central portion,

removing metal from each web so as to form a row of slots on each side of the rib thereof, the length of each slot exceeding twice the length of metal remaining between either one of its ends and the adjacent end of the next slot in the same row, and the slots on a row on one side of the rib being staggered relative to those of the row on the other side so as to form the rib into a plurality of strut-forming portions, and

c. forcing respective said outer portions away from the' central portion to thereby incline the strutforming portions of the ribs relative both to the respective outer portions and to the central portion and at the same time elongate the metal thereof by stretching it, thus forming struts joining respective outer portions and the central portion so as to in .turn form trusses, the chords of which are constituted bysaid central portion and respective said outer portions.

2..A method of producing an expanded metal product according to claim 1 comprising forming each said web to contain only one rib, and forming two rows of said slots with one row on each side of said rib.

3. A method of producing an expanded metal prod uct according to claim 1 further comprising clamping said outer portions in stretching jaws of a stretching machine, and moving said stretching jaws apart to thereby effect elongation and inclination of said strutforming portions.

.4. A method of producing an expanded metal product according to claim 1 further comprising clamping said'outer portions in stretching jaws of a stretching machine, and moving the jaws of said stretching machine apart by different amounts along their lengths to web to contain a plurality of ribs, forming a row of said slots between the ribs of each adjacent pair of ribs, forming a further row of slots on the outer side of the outermost rib in each web, and forming a still further row of slots on the inner side of the innermost rib of each web.

Claims

1. The method of producing an expanded metal product comprising: a. extruding ductile metal to form an extruded product having a constant cross-sectional shape which includes a central portion with at least three circumferentially spaced webs radiating outwardly therefrom, each web terminating at its outer end in an outer portion, and each web having a rib extending along it, each rib being between the outer portion and the central portion, b. removing metal from each web so as to form a row of slots on each side of the rib thereof, the length of each slot exceeding twice the length of metal remaining between either one of its ends and the adjacent end of the next slot in the same row, and the slots on a row on one side of the rib being staggered relative to those of the row on the other side so as to form the rib into a plurality of strut-forming portions, and c. forcing respective said outer portions away from the central portion to thereby incline the strut-forming portions of the ribs relative both to the respective outer portions and to the central portion and at the same time elongate the metal thereof by stretching it, thus forming struts joining respective outer portions and the central portion so as to in turn form trusses, the chords of which are constituted by said central portion and respective said outer portions.

2. A method of producing an expanded metal product according to claim 1 comprising forming each said web to contain only one rib, and forming two rows of said slots with one row on each side of said rib.

3. A method of producing an expanded metal product according to claim 1 further comprising clamping said outer portions in stretching jaws of a stretching machine, and moving said stretching jaws apart to thereby effect elongation and inclination of said strut-forming portions.

4. A method of producing an expanded metal product according to claim 1 further comprising clamping said outer portions in stretching jaws of a stretching machine, and moving the jaws of said stretching machine apart by different amounts along their lengths to thereby form a product wherein said outer portions are inclined to one another.

5. The method of producing an expanded metal product according to claim 1 further comprising extruding said central portion to be of hollow section throughout its length.

6. A method of producing an expanded metal product according to claim 1 comprising forming each said web to contain a plurality of ribs, forming a row of said slots between the ribs of each adjacent pair of ribs, forming a further row of slots on the outer side of the outermost rib in each web, and forming a still further row of slots on the inner side of the innermost rib of each web.