GB2095595A

GB2095595A - Sheet material and method of producing formations in continuously processed material

Info

Publication number: GB2095595A
Application number: GB8109518A
Authority: GB
Original assignee: Sections & Profiles H & E Ltd
Current assignee: Sections & Profiles H & E Ltd
Priority date: 1981-03-26
Filing date: 1981-03-26
Publication date: 1982-10-06
Also published as: WO1982003347A1; GB2095595B; BE889112A; EP0074944A1; ES8300524A1; ES502935A0; GR75686B; FI811729L; IT1137083B; DK525782A; IT8122234A0; NO823948L

Abstract

Sheet metal is passed between a pair of cold forming rolls which form a plurality of projections at one face of the sheet. These projections stiffen the sheet. One roll has a plurality of rows of teeth (4, 5, 6) and the other roll has a number of mating formations (10, 11, 12) each having a length equal to the length of a row of teeth. As viewed along the axes of the rolls, the teeth and the formations have a profile which includes two involute curves.

Description

SPECIFICATION Sheet material and method of producing formations in continuously processed material Description of Invention From one aspect, the present invention relates to continuous processing of metallic and plastics materials. In continuous processing, as the term is used herein, the material moves continuously, in contra distinction to intermittently, through a station at which the material is modified in some way, the material being of substantially endless form or of indeterminate length or having a length which is at least many times the largest dimension of the material as measured at right angles to its length.

The length of the material is that dimension which extends in the direction of travel through the station. The modification may, for example, affect the cross-sectional shape or the surface finish of the material. A further aspect of the invention relates to sheet material which can be produced by continuous processing of metallic or plastics materials.

The term "sheet material" is used herein generically to embrace generally flat metal sheet, strip metal and material of other configurations which can be formed by bending sheet or strip, or has been formed by fabrication from sheet or strip, or has been extruded and includes in its cross-section a part of sheet-like form.

It is Knows that the strength of sheet material, by which we mean the resistance to bending, can be increased by corrugating the material. Corrugations increase the resistance to bending when the material is supported at two positions spaced apart longitudinally of the corrugations and is subjected to a load at an intermediate position but does not significantly increase the strength of the material in relation to a bending load applied by supporting the material at positions spaced apart in a direction transverse to the corrugations and applying a load at an intermediate position.

Other longitudinally extending formations can be provided to improve strength in the longitudinal direction in a similar way.

It is also known that the strength of sheet material in both the longitudinal and transverse directions can be increased by providing in the material formations which are discontinuous in both longitudinal and transverse directions. Such formations can be provided in sheet material by a pressing operation.

According to a first aspect of the present invention, there is provided a method of producing formations which are either strengthening formations or piercings or a combination of both in continuously processed metallic material and in continuously processed plastics material, the formations being discontinuous longitudinally of the material, wherein the material is acted on by at least one pair of male and female mating components between which the material passes and which are so shaped that they produce said formations in the material, wherein the material is acted on by at least one further device which modifies the material and wherein the material moves past or through the further device and between said mating components continuously and at the same speed.

The method of producing formations in accordance with the invention can be used in a cold rolled forming process and in a process which comprises extrusion of plastics or metallic material. Furthermore, the cold roll forming or extrusion can be carried out at a normal speed, the formation of the piercings-or strengthening formations being carried out at the same speed.

The further device and the pair of mating components are preferably driven by common driving means.

According to a second aspect of the invention there is provided metallic or plastics sheet material having on at least one of its faces a plurality of projections, the projections being arranged in a plurality of rows with a plurality of projections in each row, each projection having been formed by stretching locally initially plain sheet material and deforming the material from its initially plain configuration to provide at an opposite face of the sheet material a depresion corresponding to the projection, and the sheet material being characterised in that the overall thickness of the sheet material is at least twice the thickness of the material at a position between projections.

By initially plain sheet material, we mean sheet material having no array of projections.

The plain sheet material may be flat or curved, for example uncoiled from a reel of strip metal.

Sheet material in accordance with the invention has a strength, as measured by subjecting the material to an increasing bending load until permanent deformation occurs, which is at least 10% greater than the strength of the plain sheet material from which it is formed and typically the strength is at least twice as great as that of the plain sheet material from which it is formed.

The projections of sheet material in accordance with the invention are preferably formed by a method in accordance with the first aspect of the invention. In a case where the purpose of carrying out the method is to increase the strength of the material, it is preferred that all of the projections are initially imperforate. When the sheet material is used, apertures may be formed through the material to receive screws or other fasteners and to permit other members to extend through the sheet material. It is also within the scope of the invention for the sheet material to be perforated at at least some of the projections.

Examples of methods embodying the first aspect of the invention and of sheet material embodying the second aspect of the invention will now be described, with reference to the accompanying drawings wherein: Figure 1 shows a cross-section through metal sheet material and cylindrical form tools acting on the material; Figures 2 and 3 show respectively crosssections through sheet material and second and third examples of tools acting on the material; Figure 4 shows a cross-section similar to Fig. 3 but with the tools at a different stage of operation on the material; Figure 5 shows a fragmentary perspective view of one example of sheet material having formations formed by the tools of Fig. 1; Figure 6 shows a fragmentary cross-section through the sheet material of Fig. 5;; Figures 7 and 8 illustrate respectively an elevation and a transverse cross-section of a second example of sheet material having formations produced by a method in accordance with the invention; Figures 9 and 10 show respectively an elevation and a transverse cross-section of a third example of sheet material; Figures 11 and 12 show respectively an elevation and a transverse cross-section of a fourth example of sheet material; and Figure 13 shows a fragmentary perspective view of sheet material having formations produced by a method in accordance with the invention and being subjected to a bending load.

Fig. 1 illustrates a method in accordance with the invention of forming projections in sheet material. The initially plain sheet material, which may be drawn from a coil of metal strip, is passed between a pair of cylindrical form tools 2 and 3 rotatable about respective axes (not shown) which are parallel. The tool 2 has at its periphery rows of projecting teeth, three successive ones of which are indicated by the reference numerals 4, 5, and 6. Each tooth has a profile, as viewed along the axis of the tool, which includes two involute curves 7 and 8 which are arranged symmetrically about a diametral plane 9 of the tool.

The tool 3 is adapted for mating with the tool 2 and has at its periphery a number of elongated formations, three successive ones of which are indicated by the reference numerals 10, 1 1 and 12. Each of these formations is arranged with its length parallel to the axis of the tool and has the same profile, as viewed along the axis, as do the teeth 4, 5 and 6.

Between adjacent formations of the tool 3 are gaps 13 which correspond in size and shape to the gaps 14 between the adjacent teeth 4, 5 and 6.

The form tools 2 and 3 are positioned in such a way that they are in mesh with one another and that between enmeshed teeth of the tool 2 and formations of the tool 3, there is maintained a uniform gap. As shown in Fig.

1 sheet material which approaches the tools is engaged by one formation on the tool 3, represented by the formation 10, and by one tooth on the tool 2,represented by the tooth 14. This formation and tooth engage opposite surfaces of the sheet material. Rotation of the form tools, one clockwise and the other anticlockwise, around their respective axes, will bring pressure to bear on the sheet material and the resultant effect will be to stretch the sheet material 1 into the desired shape and to fill the uniform gap between opposed and enmeshed teeth and formations. The involute curvature of the teeth and formations on the form tools facilitates ease of entry to and exit from the positions in which the formations and teeth of the form tools are fully engaged with the sheet material.This is an important factor in eliminating slip of the sheet material and the maintenance of uniformity of shape of and spacing between successive formations produced on the sheet material.

An example of sheet material having formations produced by the form tools illustrated in Fig. 1 is illustrated in Figs. 5 and 6, from which it will be seen that there are formed on one face of the sheet material a number of rows of projections with projections in adjacent rows being aligned with each other in a direction perpendicular to the length of the rows. Alternatively, the form tools may be arranged to form rows of projections wherein the projections in adjacent rows are aligned with each other in a direction inclined at an angle less than 90 to the length of the rows.

In a further alternative arrangement, the form tools may be arranged to form a single row of projections, each projection being elongated and arranged with its length extending either perpendicular to the length of the row or in a direction inclined at an acute angle to the length of the row.

Figs. 7 to 12 illustrate three alternative arrangements of single rows of projections in sheet material, the general transverse crosssectional shape of which is that of a channel.

In these examples, the projections are formed in the base of the channel and extend from the base in a direction towards the interior of the channel. The projections are spaced apart by a distance somewhat greater than the dimension of each projection measured along a channel. Whilst channels having single rows of projections have been illustrated, it will be appreciated that a plurality of rows of similar projections could be formed in each channel.

In Fig. 2 there is illustrated an alternative pair of mating form tools 15 and 16. These form tools may be provided with teeth or formations substantially similar to the teeth provided on the form tool 2 or substantially similar to the formations provided on the form tool 3. The form tool 16 is arranged to rotate about an axis 17 in the same manner as the form tool 2. The form tool 15 is arranged for orbital movement about a pair of axes 18 and 19 which are spaced apart in a direction along the path of travel of sheet material between the form tools.The form tools 15 and 16 are arranged with certain parts thereof in mesh with one another and it will be noted that these parts, whilst in engagement with the sheet material, undergo motion which can be resolved into components directed along the path of travel of the sheet material and components directed transversely of the path of travel.

In the particular example illustrated in Fig.

2, the number of teeth or formations of the form tools 15 and 16 which are enmeshed with each other at any moment is smaller than the number of formations and teeth of the form tools shown in Fig. 1 which are enmeshed with each other at any moment. It will be noted that, at the position where the form tool 15 withdraws from engagement with the sheet material, the sheet material is not supported by the form tool 16. The form tool 15 may be flexible or of articulated construction and is driven at a speed corresponding to that of the form tool 16.

In Figs. 3 and 4, there is illustrated a method of forming piercing in sheet material 44. The apparatus illustrated in Fig. 4 comprises a pair of mating components, namely a punch 42 and a die 43 which are moved in a similar manner to the forming tools 15 and 16 of Fig. 2 respectively. The punch 42 includes at least one row of punch elements 51 which mesh with parts of the die 43 defining recesses 50 into which corresponding parts of the sheet material are punched.

The tools illustrated in Fig. 4 differ from the tools illustrated in Fig. 2 in that the gap between punch elements 51 and the die is not uniform and in that the profile of the elements 51 is adapted to provide a piercing action, the necessary clearance angles being included.

In Fig. 3, the punch 42 and die 43 are shown in positions such that one punch element 51 a is just leaving a recess in the die and a subsequent punch element 51 b is approaching the sheet material 44. At a position 46 between the punch elements 51 a and 51 b, the sheet material is gripped by the punch and die. As movement of the punch and die continues through the position illustrated in Fig. 4, a leading edge of the punch element 51 b pierces the sheet material 44.

The punch element enters the adjacent recess of the die 43 to a depth slightly greater than the thickness of the sheet material to punch a slug out of the sheet material into the recess of the die. The punch element then withdraws from the recess in the die whilst remaining in the aperture formed in the sheet material until the punch element has moved away from the die. The punch element is then withdrawn from the sheet material without any interference with the die.

As illustrated in Fig. 2, the sheet material may pass from any of the pairs of forming tools disclosed herein to further forming tools 20, 21 which modify the material in some way, for example by forming the material into a channel-section. The forming tools 15 and 16 and the forming tools 20 and 21 may be driven by common drive means (not shown).

The sheet material may be fed from an extrusion die to the forming tools.

The sheet material illustrated in Figs. 5 and 6 is formed from plain metal strip, for exam ple mild steel or aluminium, by means of the forming tools illustrated in Fig. 1 and is then modified by further forming tools (not shown in Fig. 1) which bend the strip to the required overall cross-sectional shape. On one face of the sheet material, there are a plurality of projections which are arranged in a plurality of rows, each row containing a number of projections. In Fig. 5, two projections of one row are indicated by the reference numerals 22 and 23, and two of an adjacent row are indicated by the numerals 24 and 25. At the opposite face there are corresponding depressions.

The pitch of the projections within each row in selected according to the thickness of the plain sheet material used to produce the finished sheet material illustrated. Generally, the pitch of the projections, that is the distance between corresponding points on successive projections, within each row will be within the range four to sixteen times the thickness of the initial sheet material. The pitch of the projections measured across the rows would normally lie within the same limits as the pitch measured along the rows but may differ somewhat from the latter pitch. Typically, the pitch measured across the rows is somewhat greater than the pitch measured along the rows.

Each of the projections 22 to 25 has a substantially flat crest. By substantially flat, we mean that the crest appears to be flat on casual inspection. The form of the crest may be such that it can be shown by the use of instruments to be curved. At least adjacent to its margins, the crest will generally be slightly convex. The crests 26 to 29 of the projections 22 to 25 are at least approximately parallel to a reference plane which touches each of these crests. Each of the crests 26 to 29 has the same size and shape and is substantially rectangular. The dimension of the crest 26 measured in a direction along the row of projections 22, 23 is at least one tenth the pitch of the projections measured along the row.Similarly, the dimension of the crest 26 measured in a direction perpendicular to the length of the row is at least one tenth the pitch of the projections across the rows but is within the range 75%-i 30% of the pitch measured along the rows.

Each of the projections 22 to 25 has curved sides which merge with the sheet material between adjacent projections. The sides are generally inclined to the reference plane which touches the crests of the projections. It will be noted that sides 30 and 31 of the projection 26 which face towards adjacent rows are inclined more gently than are the other sides of the projection 26, one of which other sides is indicated at 32, which face towards adjacent projections in the same row.

Between the projection 26 and adjacent projections in the same row, there are substantially flat areas 33 and 34 of the sheet material. These substantially flat areas extend across all of the rows of projections but contribute not more than one third of the superficial area of the sheet material. Preferably, the areas 33 and 34 contribute approximately one quarter of the superficial area of the material.

The smaller dimension of each of the substantially flat areas 33 and 34, that is the dimension measured along the length of the rows of projections, is no greater than one half the pitch of the projections as measured along the rows.

In the particular example illustrated, the corresponding projections in each of the rows are aligned with each other in a direction perpendicular to the length of the rows. Alternatively, the projectons in one row may be offset in a direction along the row with respect to the projections in an adjacent row.

The overall thickness of the sheet material, by which is meant the separation between the reference plane which touches the crests 26 to 29 and a face of the sheet material remote from that plane, is at least twice the maximum thickness of the metal comprised by the sheet material. This maximum thickness occurs between projections, particularly at positions mid-way between adjacent projections. The metal in the sides of the projections, for example the sides 30, 31 and 32, is slightly thinner in consequence of having been stretched during the formation of the projections. The thickness of the metal at the crests 26 to 29 also may be somewhat less than the maximum thickness of the metal. We have found that the provision of the projections increases the strength of the sheet material, as compared with the plain sheet material from which the sheet material illustrated is formed.The overall thickness of the sheet material is increased sufficiently to increase the strength by at least 10%. A greater increase in strength results from increasing the overall thickness two-fold and the preferred overall thickness is approximately three and one half times the thickness of the initial plain sheet.

However, the sheet material shown in Fig.

5 is not stretched sufficiently during formation of the projections to perforate the material.

When first formed, each projection is imperforate. Certain projections may be perforated subsequently by fasteners when the sheet material is used.

Whilst we prefer all projections to be at the same face of the sheet material, there could be projections at both faces.

The action of the pair of forming tools 2 and 3 and the pair of forming tools 15 and 16 illustrated in Figs. 1 and 2 results in local stretching of the sheet material with consequent local reduction in the thickness of the material. This stretching partly compensates for the contraction of the sheet material which would otherwise occur during formation of the projections so that the length of the sheet material issuing from the forming tools is not less than 75% of the length of the initial piece of plain sheet material. Generally, the length of the formed sheet material will be not less than 90% of the length of the initial plain sheet material and preferably the length of the resulting sheet material is not less than 95% of the length of the initial piece of sheet material.

In Fig. 1, the tooth 5 is shown in a position where the centre of the tooth lies on a diameter common to the tools 2 and 3. This tooth has pushed the part of the sheet material with which it is engaged to the maximum displacement of that part of the sheet material relative to adjacent parts of the sheet material. It will be seen that the separation between the tooth 5 and the adjacent formations 11 and 12 of the tool 3 is, when the rolls are in the position illustrated in Fig. 3, substantially equal to the thickness of the metal forming the sides of the projection.The separation between the tooth 4 and the formation 12 and the separation between the tooth 6 and the formation 11 also are substantially equal to the thickness of the metal forming the sides of the projections so that the metal is gripped between the tooth 4 and formation 12 at a position to the rear of the tooth 5 and is also gripped by the tooth 6 and formation 11 at a position in advance of the tooth 5. Gripping of the sheet material at these positions prevents sliding of the sheet material relative to the teeth of the tools towards the tooth 6 and results in stretching of the sheet material around the tooth 6 to form the projection. The sheet material lying between adjacent rows of teeth on the tool 2 also opposes longitudinal contraction of the sheet material during formation of the projections.

It will be seen that a considerable increase in the strength of the sheet material can be brought about by the process illustrated in Fig. 1 without the length of the sheet material being reduced significantly. Accordingly, the mass of metal required for a particular duty is less when the metal is in the form illustrated in Figs. 5 and 6 than when the metal is in the form of plain sheet material. The width of the sheet material, that is the dimension extending parallel to the axes of the tools 2 and 3, is not significantly changed by the rolling process.

In Fig. 13, there is illustrated an elongated piece of sheet material having a transverse cross-sectional shape which is that of a channel. In the generaly flat and upright base 52 of the channel, there is formed a number of strengthening formations, 35 to 38. Each of these formations comprises a projection directed towards the interior of the channel and a corresponding recess facing outwardly of the channel.If the channel rests by one of its flanges 54 on supports 55 and 56 spaced apart longitudinally of the channel and the channel is subjected at its opposite flange 53 to a downwardly directed force supplied at a position between the supports 55 and 56, the force which would be necessary to cause nonelastic deflection of the base 52 of the channel would be considerably greater than the force required to cause deflection of the base of a similar channel not having the formations 35 to 38 under similar circumstances.

The method of the present invention enables initially plain and flat sheet material to be processed continuously between a number of pairs of cold forming rolls to provide the projections 35 to 38 and to form the channelsection, the material moving between the rolls of each successive pair at the same speed and without any interruption. All of the rolls can be driven by the same drive means, thus avoiding the need to provide a separate drive means for forming tools which form the projections 35 to 38.

Claims

1. A method of producing formations which are either strengthening formations or piercings or a combination of both in continuously processed metallic material and in continuously processed plastics material, the formations being discontinuous longitudinally of the material, wherein the material is acted on by at least one pair of male and female mating components between which the material passes and which are so shaped that they produce said formations in the material, wherein the material is acted on by at least one further device which modifies the material and wherein the material moves past or through the further device and between said mating components continuously and at the same speed.

2. A method according to Claim 1 wherein said further device and said pair of mating components are driven by common drive means.

3. A method according to Claim 1 or Claim 2 wherein each of those parts of said mating components which engage said material at any one moment undergoes continuous motion which can be resolved into components directed respectively along the material and transversely of the material.

4. Metal or plastics sheet material having on at least one of its faces a plurality of projections, the projections being arranged in a plurality of rows with a plurality of projections in each row, each projection having been formed by stretching locally initially plain sheet material and deforming the material from its initial plain configuration to provide at an opposite face of the sheet material a depression corresponding to the projection, characterised in that overall thickness of the sheet material is at least twice the thickness of the material at a position between projections.

5. Sheet material according to Claim 4 wherein the overall thickness exceeds three times the material thickness.

6. Sheet material according to Claim 4 or Claim 5 wherein the pitch of the projections measured across the rows is within the range 75% to 130% the pitch of the projections measured along the rows.

7. Material according to any of Claims 4 to 6 wherein there are substantially flat areas of sheet material between adjacent projections.

8. Material according to Claim 7 wherein the minimum dimension of each substantially flat area is less than one half the pitch of the projections as measured in the direction of said minimum dimension.

9. Material according to any of Claims 4 to 8 wherein the pitch of the projections along and/or across the rows is greater than four times the maximum thickness of the metal in the sheet material.

10. Material according to any of Claims 4 to 9 wherein the pitch of the projections along and/or across the rows is less than sixteen times the maximum thickness of the metal in the sheet material.

11. Material according to any of Claims 4 to 10 wherein at least the majority of the projections are imperforate.

12. Sheet material according to any of Claims 4 to 11 wherein each projection has a crest approximately parallel to a reference plane which touches the crests of a number of projections in each of number of said rows of projections.

13. Sheet material according to Claim 12 wherein each projection has sides generally inclined to the reference plane.

14. Sheet material according to Claim 13 wherein the sides of each projection are curved.

15. Material according to any one of Claims 12, 13 and 14 wherein the crest of each projection is substantially rectangular.

16. A method of producing sheet material according to any of Claims 4 to 15 wherein an initial plain piece of sheet material is passed between a pair of rolls, at least one of which has at its periphery rows of projecting teeth and the other of which has formations spaced apart by gaps into which the sheet material is pushed by the teeth to form the projections, and wherein the length of the resulting sheet material is not less than 75% of the length of the initial piece of sheet material.

17. A method according to Claim 16 wherein, when the sheet material in a local region engaged by a first tooth reaches its maximum displacement relative to adjacent parts of the sheet material, the sheet material in a region in advance of said local region is gripped between a second tooth and a corresponding formation and the sheet material in a region to the rear of said local region is gripped between a third tooth and a corresponding formation.

18. A method according to Claim 16 or Claim 17 wherein the profile of said teeth, as viewed along an axis of their roll, comprises two involute curves arranged symmetrically about a diametral plane of the roll.

19. Sheet material substantially as herein described with reference to and as illustrated in Figs. 5 and 6 of the accompanying drawings.

20. A method substantially as herein described with reference to and as shown in Fig 3 of the accompanying drawings.

21. Any novel feature or novel combination of features disclosed herein or in the accompanying drawings.