US3841134A

US3841134A - Method of making profiled rails and bodies composed thereof

Info

Publication number: US3841134A
Application number: US00324213A
Authority: US
Inventors: R Falkner; H Grune
Original assignee: RAPENA PATENT AND VERWALTUNGS AG
Current assignee: RAPENA PATENT AND VERWALTUNGS AG
Priority date: 1972-01-19
Filing date: 1973-01-16
Publication date: 1974-10-15
Anticipated expiration: 1991-10-15
Also published as: BE794217A; JPS5223622B2; GB1398463A; DE2302389B2; ES212802U; ES410595A1; FR2168462B1; CA986789A; ES212802Y; IT978284B; DE2302389A1; JPS4885470A; NL7300730A; DD102315A5; FR2168462A1

Abstract

A method of forming sharp-edged profiled rails and bodies from metal bands. A band is first corrugated, and a directrix is determined subdividing the band into first and second areas composed of the areas between the first and second exterior edges of the band and the directrix. One of the areas is moved in a swinging motion about the directrix while the transverse distance of the associated exterior edge of the area from the directrix is reduced during each part of the continuous forming process. By continuously reducing this transverse distance accrued edge tensile stresses are reduced. The initial corrugations formed in the band are increased so that the length of each envoloping line of each part of the band is longer than the enveloping line of the longitudinal profile contemplated for the corresponding part by about 2-5 percent. This allows subsequent upsetting and bending of the band with a curvature smaller than the band thickness without any thinning or weakening at the bends. Profiled rails formed in this manner may then be connected to form profiled bodies in a variety of ways.

Description

United States Patent 1191 Falkner et al.

14 1 Oct. 15, 1974 1 1 METHOD OF MAKING PROFILED RAILS AND BODIES COMPOSED THEREOF [73] Assignee: RAPENA Patentand Verwaltungs-AG, Vaduz, Liechtenstein 221 Filed: Jan. 16, 1973 21 App]. No.: 324,213

[30] Foreign Application Priority Data Primary liruminer-Milton S. Mchr Armrney, Agent, or FirmCushman, Darby & Cushman [57] ABSTRACT A method of forming sharp-edged profiled rails and bodies from metal bands. A band is first corrugated, and a directrix is determined subdividing the band into first and second areas composed of the areas between the first and second exterior edges of the band and the directrix. One of the areas is moved in a swinging motion about the directrix while the transverse distance of the associated exterior edge of the area from the directrix is reduced during each part of the continuous forming process. By continuously reducing this transverse distance accrued edge tensile stresses are reduced. The initial corrugations formed in the band are increased so that the length of each envoloping line of each part of the band is longer than the enveloping line of the longitudinal profile'contemplated for the corresponding part by about 2-5 percent. This allows subsequent upsetting and bending of the band with a curvature smaller than the band thickness without any thinning or weakening at the bends. Profiled rails formed in this manner may then be connected to form profiled bodies in a variety of ways.

8 Claims, 26 Drawing Figures PATENTED BET 914 SHEET 50F 7 METHOD OF MAKING PROFILED RAILS AND BODIES COMPOSED THEREOF The present invention relates to a method of making profiled rails and bodies composed thereof by means of the continuous forming of metal bands. Such forming is effected by rotating roll forming tools between which the said metal bands are passed. Such roll forming operations for making profiled rails are generally known and so are the roll forming machines employed therefor. Forming of the flat metal band involved is commonly effected in a large number of consecutive forming steps each between a rotating pair of rolls so that the mechanical stress applied to the material in each forming step will not exceed the admissible maximum value in order to prevent excessive stretching and weakening at the bends and the appearance of longitudinal cracks. A known measure to avoid overstressingthe material during forming consists of first corrugating the metal band in individual areas in order to facilitate subsequent hollow forming at the points involved by the provision of a sufficient quantity of material.

With the knownmethods of roll forming it has already been possible to produce comparatively complex hollow structures in a continuously moved metal band. However, the general rule here is that the metal band is at no point in forming bent with a radius of curvature smaller than the band thickness. Only then can it be en- 'sured in the conventional roll forming process that inadmissible weakening of the material is reliably avoided. The observance of this generally recognized rule has for a natural consequence that the profiled rails made by roll forming have only rounded and not square sectional structures and clearly distinguish themselves from the extruded sectional rails provided with sharp-edged profiles. 7

Since sharp-edged extrusion-formed rails are preferred, despite the higher price, for many'uses, such as for window and door frames, it is desirable to improve the methods and economics of roll forming so that comparable sharp-edged profiled rails can be formed. The method according to this invention constitutes a solution of this problem and relates to making profiled rails and bodies composed thereof by the continuous forming of metal bands which are passed between rotating pairs of forming rolls and first corrugated in certain areas to facilitate the subsequent profiling operations. This method is characterized in that a directrix is determined on the metal band which coincides with a marked longitudinal edge of the finished profiled rails and that the first area of the metal band extending from theone exterior edge to the directrix is largely held in the initial position during the subsequent forming steps, while the second area extending from the other exterior edge to the directrix is tur-ned'about the directrix away from .the initial position during the consecutive forming steps while the said exterior edge performs a swinging motion and the edge tensile stress there obtaining is reduced, that the initial corrugations are increased until their enveloping lines transversely to the metal band become longer than the enveloping line of the longitudinal profile contemplated in the area involved and that, at the bending points of the rails, the band is upset transversely to the direction of travel by using thesurplus width created by the corrugations, bent with a radius of curvature smaller thanthe band 'thickness'and formed into sharp-edged profile structures.

The method according to the invention will now be described in greater detail with regard to exemplified embodiments with reference to the drawing, FIGS. 1 through 15, in which FIG. 1 is a diagrammatic view of the consecutive forming steps in the metal band in making a complex rail, and the contemplated rotation of the basic plane;

FIG. 2 is a cross-section of the completed rail made by the forming steps of FIG. 1;

FIGS. 3 through 15 show pairsof rolls, partly at a reduced scale and partly in natural size, for the performance of forming steps in the making of the sharp-edged profiled rail according to FIG. 2;

FIG. 16 shows a profiled hollow body with folded welts made with the rail according to FIG. 2;

FIGS. 17 through 19 show further exemplified embodiments of hollow bodies with folded welts between two pairs of rails, and

bodiments of hollow bodies with welded joints between a pair of rails.

The present method will now be described in conjunction withthe forming of a flat metal band into a profiled rail provided with grooves, which is shown in cross-section in FIG. 2. It is obvious that a rail profiled with such sharp edges can be produced by extrusion but not by the methods of roll forming'so far known. The production process of this profiled rail according to the present method is shown diagrammatically in FIG. 1', the metal band 10 having the dot-dashed crosssectional configuration at the points A, B, C M, ,N,

' To begin with, a directrix 1'] is determined in the horizontal initial position'A of the metal band 10, the said directrix corresponding to a-particularly marked longitudinal edgeof the finished profiled hollow rail, in the present case the exterior edge 11 in FIG. 2. The horizontal area 11-12 of the metal band 10 extending between the exterior edge l2 of the band 10 and the directrix 11 is to remain largely in the horizontal initial position inthe present example, with the exception of the longitudinal border 14 which is bent upwards in the course of the forming operation (cf. point 0). This first area 11-12 comprises the longitudinal border 14, the side wall 15 and the boundary 16 of the longitudinal groove 17 includingits sharp-edged'flanges. As indicated in FIG. 1 at the point 0, the directrix 11 will fi nally form one, of the longitudinal edges of the com pleted profiled rail. In the initial positionA, the. first area 11-12 of the metal band- 10 is substantially less widethan the area 11 13 extending from the directrix l1 tothe exterior edge 13. In the course of forming, this entire secondat'eall-IS of the metal band 10 is turned in the clockwise direction about-the directrix and forms, with of angle against the initial position, the upper side 18"and the double-walled web '19 and, with degrees of angle against the initial position, the side wall 20 and the longitudinal-border 2l'of the completedprofiledrai l. I

In making the sharp-edged bends as at the groove 17 of the rail, the well-known difficultyarisesv that, owing to the great difference between the inner and the outer radii, theweb of materialunderg'joes stretching at these points so that the material is thinned, which results in weakening. In the present method these difficulties are overcome by sufficiently strong corrugations. While FIGS. 20 through 26 show further exemplified em- I the front side of the flat web of material still forms a straight line A at the beginning of the forming process, the web is first given a certain concave and/or convex curvature indicated at B. Such a curvature as the first step of formation is advantageous because the transverse stiffness of the web of material is thus reduced and its resistance against the subsequent forming in the continuous passage between corresponding pairs of rolls lowered. The subsequent forming steps to the point C are designed to produce indentations and convexities in the web of material at the points where the groove designated at 17 in FIG. 3 will subsequently be formed. The indentations and convexities and, respectively, corrugations are so increased that their enveloping line is longer than the enveloping line of the profile there contemplated. At point C the convexity there designated at 22, of which the enveloping line which extends from about the beginning of the convexity at point 23 to the end of the convexity at point 24, must be longer than the enveloping line between the points and 26 of the U-type channel 27 of the profile at point B. Further forming will then produce, from this presently U-type channel 27, the groove designated at 17 in FIG. 2. With a groove 17 of the present configuration, i.e., with sharp-

edged bends

28 and 29, it is of advantage to enlarge the convexity 22 (point C in FIG. 1) in such a manner that the enveloping line between the points 23 and 24 is longer by 2 to 5 percent than the enveloping line between the

points

28 and 29 of the groove 17 (FIG. 2) so that no thinning but a condensation of the wall thickness at the points 28, 29 (FIG. 2)

is obtained when the U-type channel 27 (point B, FIG. 1) is upset.

This transformation of the U-type channel 27 between the points E and L to form the groove 17 with its largely final shape is effected by an upsetting process according to the present method. Appropriately profiled co-operating pairs of rolls are preferably employed for the purpose, thesaid rolls at the same time reducing the depth of the channel 27 to the prescribed depth of the groove 17 and thus cause the folding back at the

points

28, 29 and the compressionof the same. In this upsetting operation no change in the width of the metal band to the left and to the right of the points 23, 24 occurs during forming between the points C and L.

In the forming steps leading to the cross-sections D, E and F of the metal band 10 the subsequent longitudinal groove 17 is on the one hand prepared in the first area 11-12 and, on the other, the folding for the later I80 bend ofthe double-walled web 19 begun. In the forming steps 6 through L only the final formation of the longitudinal groove 17 is performed in the. area "-12 and then'the longitudinal border 14 is bent up vertically relative to the side wall in accordance with the cross-sections M, N and 0. On the other hand, the

second area 11-13 of the metal band 10 isso formed in the steps G, H,I, K and L and the 180 bending of the double-walled web 19 is completed on the one hand and, in'addition, thegradual bending of the upperside 18 about the directrix 11 is effected. At the same time the side wall 20 vertical relative to. the web' 19 is straightened and the longitudinal border 21 bent downwards relative to the side wall 20 by 90. The profiled rail finally has the cross-section as per FIG. 2 at. the point 0.

Also for the complex forming steps contemplated in the second area 11-l3, sufficiently pronounced corrugation is produced according to the present method in the forming steps B, C, D so that the enveloping line from the directrix 11 to the exterior edge 13 in FIG. 1 is longer than the enveloping line from the edge 11 to the exterior edge 13 of the longitudinal border 21 of the completed rail according to FIG. 2.

In making rails with sharp-edged profiles according to the present method it is therefore necessary first to determine the length of the enveloping line on the cross-sectional representation of the desired rail, advantageously the length of the center line between the outer and the inner wall of the rail. The width of the metal band is then so determined that, with all profile structures and sharp bends, the length of the center line there is extended by 2 to 5 percent and the lengths of the straight portions of the center line are added to these values. This ensures that sufficient width of the metal band is available at the points subsequently subject to profiling steps in order to enablethe heavy deformations with upsetting and condensation of the band material to be effected.

As experience has shown, the upsetting process described enables mechanically perfect and sharp-edged longitudinal profiles with closely specified dimensions to be produced in only a few forming steps, the selection of the length of the indentations and convexities providing the possibility of obtaining a thickening of the material and a structural condensation at the points desired. The upsetting process is advantageously performed with profiled engaging pairs of rolls. FIGS. 3 through' l5'each show an exemplified embodiment of such engaging pairs of rolls for making a sharp-edged profiled rail as per FIG. 2.

The flat metal band 10 is first formed, possibly following pretreatment, between rotating pairs of rolls with horizontal axes in the manner shown in FIGS. 3 to 5. The convexity designated at 30serves for the production of the later longitudinal border 14 of the side wall 15 and the convexity 31 for the preparation of the longitudinal groove 17. On the other hand, the

convexities

32 and 33 serve for the preparation of the'web 19 and the later longitudinal border 21 of the side wall 20. As previously mentioned, these convexities are designed to provide sufficiently wide portions of the band for the subsequent heavy -deformation with simultaneous upsetting.

In the pairs of rolls according to FIGS. 6, 7 and 8 the forming of the convexity 31 into the groove 17 is indicated, theupsetting'action atthe two

edges

28 and 29 of this groove 17 being clearly visible in the upsetting operation between the pair of rolls according to FIG. 8. Deflection of the band to the left is prevented particularly by the fact that it is held immovable both at the I outer edge of the longitudinal border 14 and in the area of the sidewall 15 between appropriate rolls. In addition, the flat upper side 18 of the rail and the upper portion of the horizontal web 19 are prepared as well as the future longitudinal border 21 between the pairs .of rolls according to FIGS. 6,7 and 8. a

Between further pairs of rolls according-toFIGS. 9

. through 12 the horizontal double-walled web 19 is first completed and the profiling of the rail subsequently completed between the pairs of rolls according to FIGS. 13 through 15. As can be seen from the said Figures, the plane of the metal band previously arranged virtually in the horizontal is gradually rotated by 90 of angle. The bend 34 of 180 of angle at the outer end of the horizontal web 19 is changed, in the passage between the pairs of rolls according to FIGS. 10, 11, 12, from the rounded shape still shown in FIG. 9 into a more and more rectangular configuration, upsetting and material condensation occurring at the same time without which such a sharp-edged bending operation by 180 degrees of angle would not be possible. In the passage between the pair of rolls according to FIG. 15 the profiled rail obtains its final shape as per FIG. 2.

During the heavy deformation just described, which is effected with the simultaneous upsetting of the material for the creation of sharp-edged bends and profile structures, substantial tensile stresses occur particularly in the area of the outer edge 13 of the metal band 10. In order to control these tensile stresses andv to avoid both excessive longitudinal stretching and tearing of the metal band transversely to its direction of travel, the twisting motion in the area 11-13 of the metal band described with reference to FIG. 1 is employed. By utilizing this twisting motion, the rectilinear distance between the directrix l1 and the outer edge 13 of border 21 is gradually reduced resulting in reduction of the marginal tensile stresses.

In the exemplified embodiment, described with reference to FIGS. 1 through 11, of forming a metal band into a rail of complex cross-section, it has been assumed that the twisting of the area 1 l-l3 relative to the directrix is effected in the clockwise direction. If de sired, it would naturally be possible to effect twisting about the directrix 11 in the opposite direction so that the underside of the metal band 10 would then become the outside of the completed profile rail according to FIG. 2. At all-events, the present method for extreme roll forming is not limited to the exemplified'embodiment according to FIGS. 1 and 2. Y

In the present method, forming and upsetting of the metal bands is effected, as described above, by the interaction of pairs of rolls arranged on parallel horizontal shafts and rotating during the passage of the metal band involved. For reasons well known, which areexplained, by way of example, in applicants US. Pat. No. 3,689,970 it is of advantage if the metal band is under a mechanical tensile stress in the longitudinal'direction as it passes the consecutive pairs of rolls. In the said known process this tensile stress is created in that the metal band is gripped at its formed end and pulled through all consecutive pairs of rolls while all feeding force is avoided. Since an upsetting effect is exercised on the passing metal band besides the normal forming process in many of the consecutively a rranged'pairs of rolls-according to' the present" method, the necessary tractive forces are too high' to be added and provided by a single tractive devicelocated at the formed end since th'i'swould entail the hazard that the band breaks. On the other hand it must be avoided that a thrusting force is exercised on the passing metal band assuch is normally the case in pairs of rolls which are driven individually or jointly. In the present method the problem was solved -by ensuring that the consecutive pairs of rolls, while being driven individually or jointly on the one hand, on the other hand have: their effective diameters gradually enlargedby a'certain percentage so that the determinative circumferential speed of a'following pair of rolls is somewhat higher than that of the preceding pair of rolls. The passing metal band is thus subject to a longitudinal tension which is newly built up in each pair of rolls and prevents the development of a thrusting force acting onthe band surface;

Suitable dimensioning of consecutive pairs of rolls with increasing circumferential speed makes it possible to exercise the desirable longitudinal tensile stress on the passing metal band, to avoid the undesirable thrusting' forces on the band surface and nonetheless to avoid all detriment to the band surface by the tractive forcesof the roll surfaces which pull it. By way of example, it was found that with pairs of rolls with a diameter of about 220 mm on an average of the effective roll surfaces, an increase of this diameter by increments of 0.4 percent in consecutive pairs of rolls produces an increase in the circumferential speed which supplies an adequate tractive force for pulling the metal bands through the pairs of rolls, which are additionally driven, even if an upsetting process occurs in forming the metal band in such a pair of rolls. No adverse effects on the surface of the metal band can be discovered and chatter marks or other marks do not appear. On the other hand it was found that an increase in the diameter of the effective roll surfaces by only 0.05 percent is not adequate to obtain a sufficient tractiveforce.

. EXAMPLE For making a sharp-edged profile rail according to FIG. 2 an aluminium metal band'of'I-.75 mm thickness'(tolerance +0.05 or 0.1 mm) of the AlMg 2.5 alloy (DIN Standards 1725-1 or 1745-1, 2 or 3and 1784-1 respectively) was used'in the soft F 18 -22-quality with a mill-finish surface. The metal band was 232 mm wide. At a cross-section of the completed rail made 'in accordance with .the present method, the actual length of 223.5 mm. was

' measured along the centre line between the outer side andthe inner side. Accordingly upsetting and material condensation in forming was caused in the magnitude of 232 2235 8.5 mm. 'Upsetting thus amounts to approx. 3.5 percent in this rail.

It is naturally possible to employ qualities and dimensions of aluminium bands as well as of bandsmade of metals other than the abovementioned qualities in forming according to the present method. By way of example, sharp-edged profile rails may be made of highgrade steel, preferably of bands made of the material as per No. 4301 DIN Standards 17006 of the quality 5 Cr Ni 18-9, corrosion and acid-proof, cold-rolled (process III c/d), brushed, with a band thickness of 0 .9 to 1.1

The present method has above been described with reference to mak'inga sharp-edged profile rail accord ing to FIG. 2. Rails'with sharp-edged profile contours of virtually any configuration maybe made ofa flat metal band by roll' forming 'according'to' this method,

and -a number of exemplified .embodiments will be described therefor below. Inaddition,the presentmethod is however particularly suitable for making bodies composed of two or more such profiled rails, and in particular it enables sharp-edged'hollow bodies to be made by simultaneousiand-continuous 'roll forming two or more metal bands. Forthis purpose each vof the metal bands is passed through a separate set of pairs of forming rolls, profiled in consecutive forming steps from the initial position and the two profiled tails are then placed in a predetermined position relative to one another and then indetachably assembled into a unitary body.

By way of example, in parallel with making the sharpedged profile rail according to FIG. 2 in the manner described in great detail above, a second metal band can be passed through an appropriate number of separate pairs of rolls so as to make a second profile rail which enables a profiled hollow body according to FIG. 16 to be made of the completely profiled first rail according to FIG. 2. In this exemplified embodiment the second rail consists of the flat bottom 35 and the two

longitudinal borders

36 and 37 at first bent at 90 of angle relative to the bottom 35. Upon completion of the first profile rail in the pair of rolls according to FIG. the second rail has its bottom 35 forced against the longitudinal borders l4 and 21 respectively of the first rail, and the

longitudinal borders

36 and 37 of the second rail are bent around the

longitudinal borders

14 and 21 respectively of the first rail during the passage between appropriately designed additional pairs of rolls so that a folded welt connection of the associated longitudinal borders of both rails is obtained. As explained above in the context of making the first rail, preferably a sharpedged profile of the bend of the

longitudinal borders

36, 37 of 180 of angle is created in the process so that sharp-edged outer profile edges are formed at the said point. In forming the second rail the metal band must first be corrugated also for the second rail so as to enable the material to be condensed during the sharpedged bending and upsetting operation. Again, the necessary width of the second metal band is greater by 2 to 5 percent than the length of the enveloping line, measured between the outside and the inside of the metal band, of the completely formed second rail assembled with the first rail. If desired, the folded welt connection between the longitudinal borders l4 and 36 and 21 and 37 respectively may, during assembling the first and the second rail for the obtention of the sharpedged profile hollow body according to FIG. 16, be reinforced in terms of strength and anchorage by suitable means. Such means are, by way of example, roughing the longitudinal borders 14, 21' and the inside of the

longitudinal borders

36 and 37; in addition, suitable adhesives may be employed or an additional connection between the

longitudinal borders

36 and 14 and 21 and 37 respectively provided by spot welding.

A further exemplified embodiment of a sharp-edged hollow profile body composed of two rails is shown in FIG. 17. The bottom rail 40 is connected with a symmetrical hat-type rail 41 by folded welts at the common longitudinal borders so that a symmetrical hollow'body is formed. Another exemplified embodiment of a sharp-edged hollow, profile body made according to the present method is shown in FIG. 18 with the two nonsymmetrical rails 42 and 43 which are also interconnected by folded welts on the two associated longitudinal borders. The embodiment according to FIG.1"19 shows a hollow body made of the

rails

44 and 45 connected by two folded welts; apart from the sharp-edged profile structures made in accordance with the present method, dull-edged profile structures are shown at, the groove 46 whichmay naturally also be produced in processing metal bands according to 3 the present method if desired. g

In making sharp-edged profile bodies composed of two or more sharp-edged profile rails produced according to the present method, the connection may be effected not only by foldedwelts as described above with reference to FIGS. 16 through 19. In many cases it is simpler to connect the individual rails by means of a welded connection. In this case two profiled rails have their front faces forced together along two of their longitudinal borders and welded along these seams, it being possible to upset this seam in the known manner if desired. Welding may be effected with direct, lowfrequency or high-frequency current, if necessary also in an inert gas atmosphere. Welding is performed continuously during the passage of the rails to be connected by means of a suitable welding apparatus. Such welding apparatus are known and require no detailed description. If the welding seam is upset during the welding operation, the material projecting beyond the surface of the welded longitudinal borders must be removed and the sharp-edged profile body so made advantageously recalibrated. FIGS. 20 through 23 show exemplified embodiments of sharp-edged hollow profile bodies which consist of two rails simultaneously produced by roll forming in accordance with the present method and are welded together along two seam lines. The two rails are made simultaneously in a twin machine with appropriate pairs of rolls in such a manner that, when emerging from the last pair of rolls, the two profiled rails face each other with the front edges of the associated borders to be welded and pass into an appropriate welding apparatus together for the simultaneous welding of the two front edges. In the case of the hollow body according to FIG. 20, the first rail 47 is welded to the second rail 48 at the points designated at 49 and 50 respectively. In the embodiment according to FIG. 21 the first rail 51 is welded to the second rail 52 along the

longitudinalseams

53 and 54 respectively. The hollow body according to FIG. 23 is formed by welding-the first rail 59 to the second rail 60 along the welding seams 61 and 62 respectively.

Further exemplified embodiments of sharp-edged hollow profile bodies which can be made in accordance with the present method are shown in FIGS. 24 through 26. The body according to FIG. 24 is made by welding the first rail 63 to the second rail 64 along the welding seams 65 and 66. In the case of the hollow body comprising the profiled rails 67 and 68 according to FIG. 25, connection is effected by the welding seams 69 and 70 respectively. The flat hollow body according to FIG. 26 is formed by the two sharp-edged profile rails 71 welded together along the

seams

73 and 74.

It can be seen from the exemplified embodiments of bodies that are made by assembling sharp-edged profile rails as briefly described with reference to FIGS. 16 through 26, that the present method enables any bodies provided with complex longitudinal sections to be made in only one operation and in continuous production.- Obviously not only hollow bodies can be'made in this. manner but also double-walled rails of'high mechanical strength without an enclosed hollow space, suitable connection of the adjoining walls by bonding or spot welding enabling the mechanical strength to be enhanced.

In making sharp-edgedprofiled bodies according to the present method,,two flat bands, as briefly mentioned above, are first simultaneously formed into profiled rails in a twin machine by roll forming, placed in the necessary relative position and then undetachably connected. It has proved to be of. advantage for the pairs of rolls of the twin machine serving to make the complex rail to be jointly driven while the pairs of rolls required to make the less strongly profiled second rail are equipped with a separate drive. Naturally this separate drive concerns only those pairs of rolls for the second band which are required for its forming until the two rails are assembled. This separate drive, however, is so designed that an elastically operating clutch is provided between the pairs of rolls so that the transit speed of the second band and, respectively, the second rail can automatically adjust itself to the transit speed of the first rail. This is necessary because the first rail with its rigid drive must naturally determine the transit speed after the two rails are joined and because the drive of the second rail must automatically adjust to that transit speed. Suitable elastic clutches, by way of example hydrostatic drives or VOITH turboclutches which are suitable for the present purpose, are generally known and need no further explanation.

The present method of sharp-edged roll forming with upsetting and condensation of the formed metal bands at the bending points is, as previously explained, particularly suitable. for making complex profile structures. In particular, it is possible also to provide exceptionally wide metal bands with a plurality of profiled longitudinal structures by first providing appropriate indentations and convexities at individual points and then gradually roll forming while the metal band is simultaneously upset. It is thus possible, by way of example, to make the exemplified embodiments of sharp-edge hollow profile rails shown in FIGS. 20 through 26 of only a single metal band of adequate width and to connect them along only a single longitudinal seam.

A hollow rail with a cross-section according to FIG. 20 may therefore be made of only one metal band of appropriate width in that a directrix is first selected about where the left-hand'edge of the upper side is to be obtained and by providing sufiiciently deep indentations and/or convexities in the band at all points'contemplated for profiled longitudinal structures. These indentations and convexitiesmust have an enveloping line length which is larger by 2 to 5 percent than the mean enveloping line of the profile structures to be made at the points involved. There follows the step-bystep roll forming of the band, at least one of its exterior edges performing a swinging motion about the directrix while the individual bending and profiling operations are performed where the metal band is upset. Finally the two front edges of the left and of the right border of the metal band face one another at the point designated at 49 in FIG. and are joined together, by way of example by welding. In this manner, a sharp-edged hollow profile rail closed on all sides is thus made of only one metal band. 7 v

In making hollow rails according to the embodiments of FIGS, 20 through 26 ofonly one metal band, the necessary single longitudinal seam is advantageously placed at'a point which is not visible when such hollow rails-are employed. By way of example, inemploying the hollow rail accordingto FIG. 20 as a window or door frame, a longitudinal seam at point 49 will not be visible since it is located at the bottom of a longitudinal groove in which a profiled sealing strip of an elastic rubbentype material is inserted.

Weclaim: f I

l. A method of making profiled rails and: bodies composed thereof by continuous forming of at least on metal band characterized by the steps of:

a. introducing initial undulations into parts of said band to facilitate subsequent profiling of said band- 10 by bending it at bending points between rotating pairs of forming rolls; I b. determining a directrix subdividing said metal band into a first area extending from one exterior edge to said directrix, and a second area extending from the other exterior edge to said directrix, said directrix coinciding with a marked longitudinal edge to be formed into said metal band; c. turning at least one of said areas about said directrix so that the exterior edge associated with said area performs a swinging motion while the transverse distance of said associated exterior edge from said directrix is reduced step-by-step throughout the continuous forming process, thereby reducing I accrued edge tensile stresses;

d. increasing said initial undulations of said parts of said band until the enveloping lines of said parts transverse to said metal band become longer than the enveloping lines of the longitudinal profile contemplated for said parts thereby leaving surplus width, whereby no thinning of the band will occur during subsequent upsetting; and

e. transversely upsetting said metal band at said bending'points using the surplus width created by increasing said undulations, and bending said metal band with a curvature smaller than the band thickness into sharp-edged profile structures.

2..A method according to claim 1 further characterized in that a longitudinal tractive force is exerted on said metal band by a subsequent pair of rolls as said metal band passes between at least some of the pairs of forming rolls by the roll surfaces'of said subsequent pair of rolls being driven at a higher circumferential speed than the corresponding roll surfaces of the preceding pair of rolls.

3. A method according to claim 2 further characterized-in that the circumferential speed of said subsequent pair of rolls is higher by at least.0.2 percent that that of the preceding pair of rolls.

4.A method according to claim 1 further characterized in that the enveloping lines of said parts of said metal band resulting from'increasing said initial undulations are larger by 2-5 percent than the enveloping lines of the longitudinal profile contemplated for said parts. H

5. A method according to claim 1 further characterized in that first and second metal bands are formed simultaneously, -the second metal band being. twisted from its initial position during the continuous forming, profiled, and placed ina predetermined position relative to a profiled rail formed from the-first metal band, and indetachably connected to the latter to make a profiled body. t

6. Amethod according to claim 5 further characterized in that'a fold-type connection'betwe'en both profiled rails is'rnade at their longitudinal borders, the longitudinal borders beingforced together and one longitudinal edge of one rail being bentaround-the associated longitudinal borderof the other rail, the two longitudinal borders thereby becoming indetachably interconnected. p

7. A method according to claim 1 further characterized in that said metal band is formed into a sharpedged profiled rail having left and right exterior b0rders by said continuous forming'operations, said profiled rail having a cross-section corresponding to a hollow rail in which said left and right exterior borders of 1 1 12 said metal band are turned to face one another and inrails through a third group of rotating pairs of formterconnected so that a sharp-edged profiled hollow rail ing r ll f r completing said profiled body, Closed on all Sides with y (me 'Ongitudiflal Seam is d. jointly driving said first and third groups of rotating madepairs of forming rolls with the same speed,

A method of making a Profiled body composed of e. driving separately said second group'of rotating f ifig fiiit metal band by bendpairs fuming mus with. a speed autfmafically ing between a first group of rotating pairs of fomk ad usted to the speed of said first and third groups of rotating pairs of forming rolls, and

ing rolls thereby fonning said first profiled rail, continuous forming of a second metal band 10 f. connecting said first and third groups of rotating tween a second group of rotating pairs of forming P of formmg T0115 to Said Second group of rotatrolls thereby forming said second profiled rail, ing Pairs of forming T0115 with an elastically p c. connecting said first and second profiled rails, ining Clutch.

eluding by passing said first and second profiled

Claims

1. A method of making profiled rails and bodies composed thereof by continuous forming of at least one metal band characterized by the steps of: a. introducing initial undulations into parts of said band to facilitate subsequent profiling of said band by bending it at bending points between rotating pairs of forming rolls; b. determining a directrix subdividing said metal band into a first area extending from one exterior edge to said directrix, and a second area extending from the other exterior edge to said directrix, said directrix coinciding with a marked longitudinal edge to be formed into said metal band; c. turning at least one of said areas about said directrix so that the exterior edge associated with said area performs a swinging motion while the transverse distance of said associated exterior edge from said directrix is reduced stepby-step throughout the continuous forming process, thereby reducing accrued edge tensile stresses; d. increasing said initial undulations of said parts of said band until the enveloping lines of said parts transverse to said metal band become longer than the enveloping lines of the longitudinal profile contemplated for said parts thereby leaving surplus width, whereby no thinning of the band will occur during subsequent upsetting; and e. transversely upsetting said metal band at said bending points using the surplus width created by increasing said undulations, and bending said metal band with a curvature smaller than the band thickness into sharp-edged profile structures.

2. A method according to claim 1 further characterized in that a longitudinal tractive force is exerted on said metal band by a subsequent pair of rolls as said metal band passes between at least some of the pairs of forming rolls by the roll surfaces of said subsequent pair of rolls being driven at a higher circumferential speed than the corresponding roll surfaces of the preceding pair of rolls.

3. A method according to claim 2 further characterized in that the circumferential speed of said subsequent pair of rolls is higher by at least 0.2 percent that that of the preceding pair of rolls.

4. A method according to claim 1 further characterized in that the enveloping lines of said parts of said metal band resulting from increasing said initial undulations are larger by 2-5 percent than the enveloping lines of the longitudinal profile contemplated for said parts.

5. A method according to claim 1 further characterized in that first and second metal bands are formed simultaneously, the second metal band being twisted from its initial position during the continuous forming, profiled, and placed in a predetermined position relative to a profiled raIl formed from the first metal band, and indetachably connected to the latter to make a profiled body.

6. A method according to claim 5 further characterized in that a fold-type connection between both profiled rails is made at their longitudinal borders, the longitudinal borders being forced together and one longitudinal edge of one rail being bent around the associated longitudinal border of the other rail, the two longitudinal borders thereby becoming indetachably interconnected.

7. A method according to claim 1 further characterized in that said metal band is formed into a sharp-edged profiled rail having left and right exterior borders by said continuous forming operations, said profiled rail having a cross-section corresponding to a hollow rail in which said left and right exterior borders of said metal band are turned to face one another and interconnected so that a sharp-edged profiled hollow rail closed on all sides with only one longitudinal seam is made.

8. A method of making a profiled body composed of first and second profiled rails by a. continuous forming of a first metal band by bending between a first group of rotating pairs of forming rolls thereby forming said first profiled rail, b. continuous forming of a second metal band between a second group of rotating pairs of forming rolls thereby forming said second profiled rail, c. connecting said first and second profiled rails, including by passing said first and second profiled rails through a third group of rotating pairs of forming rolls, for completing said profiled body, d. jointly driving said first and third groups of rotating pairs of forming rolls with the same speed, e. driving separately said second group of rotating pairs of forming rolls with a speed automatically adjusted to the speed of said first and third groups of rotating pairs of forming rolls, and f. connecting said first and third groups of rotating pairs of forming rolls to said second group of rotating pairs of forming rolls with an elastically operating clutch.