US3251209A

US3251209A - Machine and method for shaping sheet material

Info

Publication number: US3251209A
Application number: US173262A
Authority: US
Inventors: Cookson William
Original assignee: Cookson Sheet Metal Developments Ltd
Current assignee: Cookson Sheet Metal Developments Ltd
Priority date: 1961-02-17
Filing date: 1962-02-14
Publication date: 1966-05-17
Anticipated expiration: 1983-05-17
Also published as: GB1010891A

Description

w. COOKSON 3,251,209

MACHINE AND METHOD FOR SHAPING SHEET MATERIAL May 17, 1966 3 Sheets-Sheet 1 Filed Feb. 14, 1962 May 17, 1%6 w. cooKsoN 3,251,209

MACHINE AND METHOD FOR SHAPING SHEET MATERIAL Filed Feb. 14, 1962 s Sheets-Sheet 2 N N \w M A w. COOKSON 3,251,209

MACHINE AND METHOD FOR SHAPING SHEET MATERIAL May 17, 1966 3 Sheets-Sheet 5 Filed Feb. 14, 1962 3,251,209 MACHINE AND METHOD FOR SHAlPlNG SHEET MATERIAL William Cookson, Fareliam, England, assignor to COOlC- son Sheet Metal Developments Limited, London, England, a company of Great Britain and Northern Ireland Filed Feb. 14, 1962, Ser. No. 173,262 Claims priority, application Great Britain, Feb. 17, 1Q61, 6,003/ 61 10 Claims. (Cl. 72--181) This invention relates to a machine and a method for shaping sheet material, preferably sheet metal, and more particularly for forming ribs in sheet material.

One well known process for forming ribs, such as are required for some forms of roofing sheet in sheetmetal, consists of cold rolling, that is to say, passing the flat metal sheet between one or more pairs of shaping rolls, in the nature of plunger and die rollers, keeping the sheet in one plane throughout the process. There is a tendency on the part of the metal to stretch and break as it passes through a pair of rollers, that tendency increasing (other factors remaining constant) with the extent of deformation imparted by these rollers. Thus, if a deep rib is required, the sheet is passed between a number of successive pairs of rolls in stands, each pair of which prgres sively increases the depth of the rib by shrinking or drawing-in the Hat metal across the width of the sheet, until the desired depth is achieved in the last pair of rolls.

In my Patent No. 3,184,942, May 25, 1965, there is described a method of forming a deep rib in a sheet, preferably a metal sheet, by means of co-operating ribforming rolls, said method comprising deforming to a valley-shape a longitudinal portion of the sheet having a width substantially greater than the width of the strip of the sheet from which the rib is to be formed and having as its apex, the said strip from which the rib is to be formed, and acting on the said strip with one pair of cooperating rib-forming rolls to form a deep rib at a single pass through the said one pair of rolls.

The present invention provides, in one of its aspects, a method of forming a plurality of deep ribs in a sheet, preferably a metal sheet, by means of a like plurality of co-operating pairs of.rib-forming rolls, which method includes the steps of deforming to a valley shape a plurality of longitudinal portions of the sheet each having a width substantially greater than the width of the strip of the sheet from which the rib is to be formed and having as its apex the strip from which the rib is to be formed, and acting on each strip with a pair of co-operating ribfOrming rolls to form a plurality of deep ribs in the sheet at a single pass through the said plurality of pairs of rolls.

In my aforementioned patent there is also described and claimed a machine for forming a longitudinal rib in a sheet, preferably a metal sheet, comprising means for deforming to a valley-shape a longitudinal portion of the sheet having a width substantially greater than the width of the strip of the sheet from which the rib is to be formed and having as its apex the said strip from which the rib is to be formed and a single pair of co-operating rib forming rolls to act on the said strip at the apex of the valley-shaped portion of the sheet to form a deep rib at a single pass.

The present invention also provides, in another of its aspects, a machine for forming a plurality of deep ribs in a sheet, preferably a metal sheet, which includes means for deforming to a valley shape a plurality of longitudinal portions of the sheet each having a width substantially greater than the width of the strip of the sheet from which the rib is to be formed and having at its apex the strip from which the rib is to be formed and a plurality of pairs of co-operating rib-forming rolls to act on the strips 3,2513% Patented May 17, 1966 at the apices of the valley shaped portions of the sheet to form deep ribs therein at a single pass.

In order that the invention may be clearly understood and readily carried into efifect, an embodimentthereof,

. transforming pieces of a machine embodying the invention,

FIG. 2 shows in perspective view a sheet passing between the forming rolls and over the transforming pieces shown in FIG. 1, 1

FIG. 3 is an elevation in transverse section of a typical pair of forming rolls with a metal sheet interposed therebetween, I

FIG. 4(a) is a diagrammatic view of a transforming piece,

FIG. 4( b) is a diagrammatic view of a centre rib guide,

FIGS. 5(a), (b), (c), (d) and (e) show cross-sections of the sheet at various stages in the course of its passage through the machine, and

FIG. 6 shows in part sectional elevation a modified pair of forming rolls 'with associated deforming means.

Referring to FIGS. 1 to 5 of the drawings, a shaping device 10 is shown in FIG. 1, consisting of wood, steel, or other suitable material and having an inverted valley shape. As the sheet or coil is drawn over the shaping device 10 by the action of rollers (to be mentioned presently) it is deformed or additionally deformed into inverted valley shape. The cross section of the sheet 12 as itleavesthe shaping device 10 is shown in FIG. 5(a).

FIGS. 1 and 3 show the first pair of forming rolls (the stand construction isomitted for clarity) namely a female roller 14 and a male roller 16. The female roller 14 has a pair of support flanges 18 (see FIG. 3) inclined at an angle to each other equal to the angle of the valley section between the walls 20 of the sheet 12 and converging towards its apex. The roller 16 has a pair of support flanges 22 inclined at the like angle. The parts of the rollers 14, 16 disposed between the flanges 18, 22 are intended respectively to form the deep centre rib in the sheet and hence will be called rib forming parts and designated 24 and 26 respectively. Thus the flanges 18 are spaced from one another transversely of the machine 'by the rib forming part 24 and the same may be said of the flanges 22 by the rib forming part 26. The flanges are co-axial with the respective rib forming parts and project laterally from their sides. Clearly, the diameters of the flanges 22 on the male roller 16 decrease outwardl from the central plane of the rolls and the diameters of the flanges 18 on the female roller 14 increase outwardly from that plane. The cross section of the rib forming parts 24, 26 corresponds substantially to the desired cross.

section of the centre rib to be formed. The cross sections of the rib forming parts 24, 26 and the angles and position of the supporting flanges 18, 22 are such that the two rollers mate except for a substantially uniform slot-like clearance gap 28 therebetween and that transversely spaced parts of the sheet lie against the inclined surfaces. The gap 28 maintains the valley section of the sheet 12 and thereby allows the metal to be drawn easily from the edges of the sheet to form the rib.

The forming rolls 14, 16 form a rib 32 in the sheet 12 which, as it leaves those rollers, is of the cross-section shown in FIG. 5(1)). Thus, it has two walls 30 and the centre rib 32, the walls 30 are still at an angle to one another substantially equal to the angle of the valley section. The rib 32 is formed along the strip at the apex 34 of the valley section in the sheet. The gap 28 is greater than the thickness of the metal of the sheet since if it were otherwise, the metal would be impeded from being drawn laterally into the desired shape with consequent risk of stretching and tearing of the metal. As the sheet passes through the pair of rolls 14, 16 the marginal portions of the sheet are temporarily deformed as can be seen from FIG. 2. After passing through the rolls 14, 16 the walls gradually shape up that is return to a position substantially parallel with the shafts of the rollers. The sheet therefore assumes a cross section as shown in FIG. 5(0) after leaving the rolls 14, 16. This phenomenon arises through a combination of the shapesof the rolls 14, 16, the valley section of the sheet prior to entering the rolls 14, 16 and the inherent spring back or faculty of recovery from deformation (i.e. resilience) of the sheet when this is freed from restraint after it has passed through the rolls 14, 16.

In FIG. 1, two further pairs of forming

rolls

36, 38 and 40, 42 which are transversely aligned and similar to rolls 14, 16 are illustrated for forming side ribs 41 in the sheet. The stand construction of these rolls is omitted for clarity. In FIG. 4(a) a transforming piece 44 made of wood, steel or other suitable material is shown. The piece 44 has a base 46 and a tapering top surface 48 changing or transforming from a fiat receiving end 52, to a rear portion 50 of rounded section corresponding in shape to the shape of the rib forming parts of the rolls 36, 38; and 40, 42. Two transforming pieces 44 are positioned between the pairs of rolls 36, 38; 40, 42 on a table 54 situated between the roll stands as can be best seen in FIG. 1.

In FIG. 4(b) a centre rib guide 56 made of wood, steel or other suitable material is shown which has its top portion 58 shaped to the contour of the centre rib 32 of the sheet.

The transforming pieces 44 and the centre rib guide 56 together constitute a mandrel unit.

In FIG. 1 the rib guide 56 is situated on table 54 between the roll stands and its purpose is to engage the centre rib 32 of the sheet thereby to locate it and guide the sheet from the rolls 14, 16 to the rolls 36, 33; 4t), 42. The rib guide 56 extends to between the rolls 36, 38; 40, 42 and has its projecting end slightly below the top of rolls 38, 42.

In FIG. 1 two holding down devices 60 preferably consisting of rectangular wood blocks, are suitably positioned to hold the sheet fairly loosely in contact with the receiving ends 52 of pieces 44 at the position where the sheet assumes the cross-section shown in FIG. 5(a).

In FIG. 2, sheet 12 drawn from a coil or strip stock, is shown being deformed and rolled to the desired profile illustrated in FIG. 5(e) in pairs of rolls 14, 16; 36, 38 and 40, 42. Suitable rail guides 62 are situated in front of and below the mating parts of rolls 14, 16 and their purpose is to support the stock feed in correct alignment with the rolls 14, 16. The side guides 62 are situated substantially below the apex 34 of the initial valley section and below the free edges of the walls 30 of the sheet where it is in valley section. By positioning the guides 62 in this way there is an unsupported length of the sheet 12 between the side guides 62 and the rolls 14, 16 which accommodates the changes in cross sectional shape of the sheet from flat to valley section. In the result there is little or no tendency for the sheet to pucker as the rib 32 is being formed.

As the sheet leaves the rolls 14, 16 it is held loosely between the holding down devices 60 and the receiving ends 52 of pieces 44. Whenthe sheet is constrained in this manner it assumes the section shown in FIG. 5(a). As the sheet is drawn over the transforming pieces 44 by the action of the driven rolls 36, 38; 4t} and 42 the sheet is gradually deformed by those pieces and by the flanges of the rolls to a section having a longitudinal portion of inverted valley shape in each side of centre rib 32. At this stage the centre rib of the sheet is locally displaced downwardly to allow the valley shape to be formed and the sheet to be accepted by the inclined support flanges of the rolls 36, 38; 4t), 42 in the second stand. Also in the process the margins of the walls 30 of the sheets are deformed beyond and below the level of table 54. Valley sections 64 are therefore formed after transitional sections 66. FIG. 5(d) shows the sectional shape of the sheet as it passes between rolls 36, 38; 40, 42. There, the side ribs are formed in the strips at the apices of the portions of valley shape. The centre rib 32 is lower than ribs 41, and is connected by portions 72 sloped at the angle of the support flanges of the rolls 36, 38; 40, 42.

Alternatively, instead of locally displacing downwardly centre rib 32, the rib is allowed to continue to roll in the horizontal plane and rolls 36, 38; 40, 42 are positioned in the second stand sufficiently higher than rib 32 to accept the sheet between the inclined flanges of the rolls. For the roll forming of more ribs in wider sheet, additional rolls in following stands (not shown) are positioned progressivelyhigher in relation to the horizontal bed of the machine. By such means the sheet passes through each stand at increasingly higher levels in stairlike fashion, with the tops of the ribs always lying parallel to the machine bed.

As the sheet passes through the machine it is temporarily deformed and shaped by a combination of rolling and drawing over the transforming and guiding devices, but because the material has been freely drawn through the rolls without undue restraint there is no substantial permanent stretching of the metal. Consequently a short distance beyond the pairs of rolls 36, 38; 40, 42, the sheet assumes the final cross section shown in FIG. 5 (e), with the ribs 32 and 41 upstanding from the general flat plane of the sheet.

The rollers are made from suitable tool steel, and are journalled in end bearings provided in a frame. The rolls are driven by a suitable means through the intermediary of gearing; none of these features are shown but their provision will not present any problem to a skilled engineer.

In this example each pair of forming rolls 14, 16; 36, 38; 40, 42 forms a deep rib to its full depth in one pass through the pair of rolls. The rib is not progressively formed in stages by successive pairs of rolls. Such deep ribs are most suitably formed in a single pass by pairs of large diameter rollers. It has been found that large diameter rolls shape the ribs more gradually, distance for distance (measured along the circumference of the roller) than smaller diameter rollers.

In the modification shown in FIG 6, rib-forming rolls 76, 78 are shown without support flanges. In their stead are used co-operating pairs of

guides

80, 82 having inclined surfaces. These are disposed so as to assist in forming or maintaining the valley section of sheet 12 prior to its entry between the forming rolls 7 6, 78.

By means of the foregoing machine, the transformation of a coil or strip from and to a flat plane forming a plurality of deep ribs in the process, is accomplished without giving rise to permanent stresses in the sheet which result in buckling or similar distortion of the finished product. In the embodiment of the invention and the modification described above, the width of the metal coil before its passage through the machine is 30 inches, the height of the ribs is 2 inches, the material hard sheet aluminium of 0.028 inch thickness, the forming rolls are '18 inches in diameter and the distance between the forming roll stands 32 inches.

Besides considerably reducing the number of rolls and stands required for producing deep ribs in metal sheet by the previous roll forming processes, the technique of what we term deformation rolling can, as explained above, produce ribs in sheets of different metal thickness in the same rolls because the clearance gap between the rolls is not critical as with some existing machines which may require separate rolls for each gauge or thickness of sheet material.

What I claim and desire to secure by Letters Patent is:

1. The method of forming in a continuous manner in successive steps, a plurality of deep ribs in a sheet hav ing a plane profile by means of a like plurality of pairs of rib forming rolls, one male and the other female, comprising forming a first rib in the sheet by causing the sheet to assume a first single valley cross-section in advance of a first pair of rib forming rolls and drawing the sheet in said form into the first pair of rolls with the apex of the valley engaging over the crest of the male roll, and forming at least a further rib inthe sheet flanking the first rib after its formation by causing a longitudinal portion of the sheet flanking the first rib to assume a second valley cross-section in advance of a further pair of rib forming rolls disposed behind and to one side of the first pair of rib forming rolls, said longitudinal portion being of a width substantially greater than the width of the strip of the sheet from which the further rib will be formed, and drawing the second assumed valley cross-section into the further rib forming rolls with,

the apex of the valley engaging over the crest of the male roll and with one side of the valley being freely drawn laterally into the rolls and causing the finished profile of the sheet, except for the ribs, to assume a plane profile.

2. The method according to claim 1 in which two outer ribs, each flanking the first rib on opposite sides are subsequently formed simultaneously by causing longitudinal portions of the sheet each flanking said opposite sides of the first rib to be drawn through two pairs of further rib forming rolls.

3. The method according to claim 2 in which the apices of the valleys are all upwardly directed and the sheet is drawn upwardly into each 'pair of rolls.

4. The method according to claim 3 in which the outer ribs are formed at a level above that occupied by the first rib as it passes the two further pairs of rib forming rolls and the inner walls of the valley sections forming in advance of such further pairs of rib forming rolls slant upwardly and outwardly from the base of the first rib.

5. A machine for forming in a continuous manner in succussive steps in a sheet a number of deep ribs comprising in combination, a first roll stand carrying at least one but not more than two pairs of rib forming rolls, each pair consisting of a male roll and a female roll arranged to receive therebetween a sheet to be acted upon and form in it a number of first ribs equal in number to the number of pairs of rolls in the stand and a second roll stand behind the first roll stand containing at least one but not more than two pairs of rib forming rolls, each and means for imparting to a portion of the sheet substantially wider than the strip of the sheet from which the rib is to be formed in advance of each of the pairs of rib forming rolls a valley cross-section the apex of which is directly in advance of rib forming parts of the rolls, said means in the case of the rib forming rolls in the second roll stand being located between the first and second roll stands, the rolls in each roll stand being so disposed forallowing free drawing in parallel to the axes thereof at least one side of the valley section as it passes through the rolls and the rib is formed.

6. A machine according to claim 5 wherein the pairs of rib forming rolls each consist of a lower male roll and an upper female roll, said rolls having respectively plunger and die rib forming parts flanked by support flanges projecting laterally of said rib forming parts co-axially therewith, the diameter of the support flanges on the lower male roll of each pair decreasing outwardly from the mid-plane of the roll.

7. A machine according to claim 6 in which the diameter of the support flanges on the upper female roll of each pair of rolls progressively increases outwardly from the mid-plane of the roll.

8. A machine according to claim 7 wherein the rolls in the second roll stand are mounted at a level so that the level at which these rolls engage the sheet is situated at a vertical level above that at which the rolls in the first stand engage the sheet.

9. A machine according to claim 6 wherein all .the rib forming rolls are mounted with the nips of the rolls at the same vertical level.

10. A machine according to claim 9 wherein the means for imparting to the longitudinal portions of the sheet in advance of each of the pairs of rolls in the second roll stand include tapered transforming pieces flanking the first rib when formed and guiding said rib to a level below that at which the rolls in the second roll stand engage the sheet.

References Cited by the Examiner UNITED STATES PATENTS CHARLES W. LANHAM, Primary Examiner.

R. J. HERBST, Assistant Examiner.

Booth 15377

Claims

1. THE METHOD OF FORMING IN A CONTINUOUS MANNER IN SUCCESSIVE STEPS, A PLURALITY OF DEEP RIBS IN A SHEET HAVING A PLANE PROFILE BY MEANS OF A LIKE PLURALITY OF PAIRS OF RIBS FORMING ROLLS, ONE MALE AND THE OTHER FEMALE, COMPRISING FORMING A FIRST RIB IN THE SHEET BY CAUSING THE SHEET TO ASSUME A FIRST SINGLE VALLEY CROSS-SECTION IN ADVANCE OF A FIRST PAIR OF RIB FORMING ROLLS AND DRAWING THE SHEET IN SAID FORM INTO THE FIRST PAIR OF ROLLS WITH THE APEX OF THE VALLEY ENGAGING OVER THE CREST OF THE MALE ROLL, AND FORMING AT LEAST A FURTHER RIB IN THE SHEET FLANKING THE FIRST RIB AFTER ITS FORMATION BY CAUSING A LONGITUDINAL PORTION OF THE SHEET FLANKING THE FIRST RIB TO ASSUME A SECOND VALLEY CROSS-SECTION IN ADVANCE OF A FURTHER PAIR OF RIB FORMING DISPOSED BEHIND AND TO ONE SIDE OF THE FIRST PAIR OF RIB FORMING ROLLS, SAID LONGITUDINAL PORTION BEING OF A WIDTH SUBSTANTIALLY GREATER THAN THE WIDTH OF THE STRIP OF THE SHEET FROM WHICH THE FURTHER RIB WILL BE FORMED, AND DRAWING THE SECOND ASSUMED VALLEY CROSS-SECTION INTO THE FURTHER RIB FORMING ROLLS WITH THE APEX OF THE VALLEY ENGAGING OVER THE CREST OF THE MALE ROLL AND WITH ONE SIDE OF THE VALLEY BEING FREELY DRAWN LATERALLY INTO THE ROLLS AND CAUSING THE FINISHED PROFILE OF THE SHEET, EXCEPT FOR THE RIBS, TO ASSUME A PLANE PROFILE.