US3226965A

US3226965A - Device to achieve multiple reverse flexing of continuous steel strip

Info

Publication number: US3226965A
Application number: US164522A
Authority: US
Inventors: Edward D Higgins
Original assignee: Continental Can Co Inc
Current assignee: Continental Can Co Inc
Priority date: 1962-01-05
Filing date: 1962-01-05
Publication date: 1966-01-04
Anticipated expiration: 1983-01-04

Description

Jan. 4, 1966 D. HIGGINS 3,226,965

E. DEVICE TO ACHIEVE MULTIPLE REVERSE FLEXING Filed Jan. 5, 1962 OF CONTINUOUS STEEL STRIP 2 Sheets-Sheet 1 a 3mm 02 ,EDWAED 6::

BY I My 1 m6 ATTORNEYS a; F l

Jan. 4, 1966 E D. HIGGINS 3,226,965

DEVICE TO ACHIEVE MULTIPLE REVERSE FLEXING OF CONTINUOUS STEEL STRIP Filed Jan. 5, 1962 2 Sheets-Sheet 2 So I: G, 2 47 INVENTOR EDWAED D. Hleemls ATTORNEYS United States Patent 0 3,226,965 DEVI'CE T0 AQHTEVE MULTHPLE REVERSE FLEXHNG GE CQNTTNUQUS STEEL STRIP Edward D. Higgins, Palos Heights, lll., assignor to Continental an Company, fine, New York, N.Y., a corporation of New York Filed Jan. 5, 1962, Ser. No. 164,522 1t Claims. (Cl. 72-192) This invention relates in general to new and useful improvernents in apparatus for use in the manufacture of sheet metal, and more particularly relates to a novel apparatus to achieve multiple reverse flexing of work hardened continuous steel strip to increase the ability thereof to withstand fabrication by increasing the ductility of such strip.

In the manufacture of certain types of sheet metal, particularly thin steel strip and sheet, the necessary reduction in thickness is obtained by heavily cold rolling the starting metal stock. The resultant strip has been severely cold worked, frequently by more than 80% reduction, and although very hard and strong, it does not have adequate ductility for many uses. mate product is to be tin plated steel for the making of cans, the hard rolled steel in conventional practice must be annealed and then temper rolled to a reduction of about only 1%. This very slight reduction imparts flatness and also masks the yield point elongation of such steel which otherwise would be detrimental to can making or other fabricating processes which might be employed, and yet this minor reduction does not noticeably impair the ductility resulting from the prior anneal.

When such conventional tin plate is desired in thinner gauges, i.e., less than .008 inch thick, a variety of difliculties are encountered. For example, when thin rolled strips are pulled through the electrolytic tinning line, the applied tensile force used to pull the strip sometimes results in expensive fracture of the strip Within the electroplating line. In order to avoid this difliculty, the steel industry has introduced a new type of tin plate to provide the desired thinner gauges of metal, which new type of plate is produced in such a manner that it is less costly, per unit area, to produce than heretofore.

The new type of tin plate is produced by additional substantial cold rolling reductions after the metal strip stock has been annealed and plated with tin. The initial cold rolling is to a somewhat thicker gauge than normal; followed by annealing, tin plating and a subsequent cold reduction of the order of 30% to 60%, resulting in a finished gauge of as low as 0.0944 inch, and even lower, if desired. Unfortunately, while the finished product has a desired thinness and also a desirable high strength and hardness, these qualities have been obtained by an almost complete sacrifice of ductility and by a marked directionality of properties. Tensile testing of such material indicates a transverse elongation of the order of 1% or less in a 2 inch gauge length and a longitudinal elongation of from less than 1% to 3%.

An alternative new means of producing such hard and strong but brittle tiuplate is to anneal cold rolled steel at a thickness appreciably greater than that desired in the final tinplate and then cold roll 30% to 60% to the final gauge followed by electroplating and flow brightening of the tin coating. This differs from the foregoing process only in that the tin coating is applied after the final cold rolling rather than previous thereto. However, the properties of the steel are essentially identical for equivalent cold reductions so that the problems of utilizing this material are the same.

When cans, which have been made from this new type of tin plate, have the rolling direction parallel to the can axis, severe fracturing of the plate is encountered during For example, if the ulti-' Patented Jan. 4, 1966 manufacture. Fracture occurs primarily during forming of the side seam hook and during flanging of the can body. These can making operations are ones in which large 10- calized plastic tensile strains are introduced into the metal in a direction transverse to the rolling direction. When these problems are avoided by having the can bodies made with the rolling direction of the tin plate in a circumferential direction, fracture of the cans has been encountered when, during rough handling, dents were produced in the body wall below the end seam seal. Therefore, in order to exploit further this newly introduced type of tin plate for can making, some of the ductility of the metal must be restored. Thermal treatment, such as annealing after the second cold reduction, is not practical since the tin coating, which is already on the steel, will alloy with the steel at the required steel annealing temperatures and thereupon form an excessive amount of undesired hard and brittle tin-iron alloy.

The present invention is directed to a machine for operating on this new type of tin plate which has been given a substantial .cold reduction after tin plating to increase the ductility thereof, and one object of this invention is to provide a novel apparatus to achieve multiple reverse flexing of the work hardened continuous steel strip to increase the ability thereof to withstand fabrication by increasing the ductility thereof, and at the same time, resulting in only minor reductions in the strength of the steel strip.

In the past, metal sheets to be formed into can bodies have been subjected to a grain breaking process wherein immediately prior to the shaping of the sheets in a can making process, the sheets are passed through a grain breaker to assure the formation of a perfectly round cylinder by preventing the formation of flutes in the can body cylinder as fabricated at high speeds. This grain breaker consists of several rollers disposed in vertical relation. However, while these rollers have produced the desired grain breaking and curvature of the individual can body blanks, the flexing of the sheets has been relatively light, and there has been no accompanying increase in ductility of the sheets so mechanically treated.

In the steel industry, in order to remove ripples from steel sheets, as Well as other steel shapes, it is common practice to pass the steel through leveling rollers. As the steel passes through the leveling rollers, it is ultimately flexed with a resultant flattening of the metal. Such roller levelers used today have only a limited number of pairs of alternatingly spaced rollers of approximately 1 /2 to 3 inches in diameter. However, the steel industry does not flex the steel enough to substantially exceed the yield strength except at initially non-flat portions sinoe the objective is to simply flatten or straighten and not to change any of the physical or mechanical properties of the material.

The present invention proposes broadly to use a novel machine having a series of interlocking rollers such as in well known roller levelers, but wherein the number of rollers are greatly increased, the diameters of the rollers are greatly decreased and all of the rollers roll along upper and lower guides and are constrained at their ends by upper and lower chains so as to provide both an increase in the number of flexures as compared to roller leveling, and at the same time, all the aforesaid elements combine to provide for a more severe stressing of the metal wherein during a stressing of the metal, the outer layers of the sheet or strip are stressed beyond the initial yield strength of the metal of the sheet or strip.

Another object of this invention is to provide a novel apparatus for reverse flexing a hardened metal strip to increase the ability thereof to withstand fabrication by increasing the ductility of the strip, the apparatus including a large number of small diameter rollers wherein the diameter of the rollers varies between /8 inch and /2 inch, and wherein a strip passed over the rollers will be severely stressed a large number of times and wherein the stressing of the strip will be reversed to increase the ductility of the strip and at the same time increase the ability of the strip to withstand fabrication.

Still another object of this invention is to provide a novel apparatus through which a hardened steel str1p may be fed on a continuous basis to increase the ability thereof to withstand fabrication by increasing the ductility thereof, the apparatus including two endless roller assemblies, each roller assembly being so guided to have opposed runs thereof disposed in parallel intermeshed relation so that a hardened steel strip passed therebetween will be severely flexed, the rollers being backed up by the guides for the roller assemblies wherein the small diameter rollers are sutficiently supported against flexure while severely flexing the strip.

Another object of this invention is to provide a novel apparatus for reverse flexing a work hardened continuous steel strip, the apparatus including a pair of guides having opposed spaced apart guide surfaces, an endless roller assembly entrained about each guide and having rollers engaged with the guide surfaces thereof, each of the roller assemblies being formed of a large number of small diameter rollers with each of the rollers having a diameter ranging from /8 inch to /2 inch, and the rollers engaging the guide surfaces so as to prevent deflection of the rollers during the application of a flexing force on a steel strip disposed between the roller assemblies, even though the rollers are of a relatively small diameter.

A further object of this invention is to provide a novel apparatus for reverse flexing work hardened continuous steel strip, the apparatus including a pair of guides having opposed parallel guide surfaces, an endless roller assembly entrained over each of the guide surfaces and having opposed runs thereof disposed in intermeshed relation, each of the roller assemblies being formed of a plurality of long rollers and terminal links, the rollers each rolling upon the guide surface of an associated one of the guides, and the links having projections disposed outwardly of and alongside the guides so as to maintain the d1- rection of movement of the roller assemblies as the roller assemblies move along the elongated guide surfaces.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:

In the drawings:

FIGURE 1 is a schematic side elevational view of the apparatus which is the subject of this invention and shows the general arrangement of the components thereof.

FIGURE 2 is a transverse vertical sectional view taken along the line 2-2 of FIGURE 1 and shows further the details of the apparatus.

FIGURE 3 is an enlarged fragmentary horizontal sectional view taken along the line 3-3 of FIGURE 2 with a portion of the roller assembly of the apparatus broken away, to clearly illustrate the details of the lower roller assembly, the lower guide and certain of the lower sprockcts for driving the lower roller assembly.

FIGURE 4 is an enlarged fragmentary vertical sectional view taken along the line 4-4 of FIGURE 2, and shows the specific relationship of the roller assemblies with respect to the drive sprockets therefor and the relationship of the links of the roller assemblies with respect to the guides.

FIGURE 5 is an enlarged fragmentary perspective view showing the specific details of construction of one of the roller assemblies.

In FlGURE 1 of the drawings, there is schematically illustrated the apparatus which is the subject of this invention for preparing work hardened continuous steel strip for use by the can making industry. The apparatus, which is generally referred to by the numeral 8, has associated therewith a coil pay-out stand supporting a coil C of work hardened continuous steel strip S. Also associated with the apparatus 8 is a recoiler 10 having supported thereby a further coil C on which the strip S is reeled. Prior to the entry of the strip S into the apparatus 8, the strip S passes between a pair of feed control rollers ill, 11.

The strip S is relatively thick when it is initially rolled as compared to the final product. The strip S after being initially rolled, was annealed, after which it was passed through an electroplating bath in the customary manner so that tin coatings are applied to opposite faces thereof. The strip S, after having been coated, was then passed through a series of cold reduction rollers wherein the thickness of the strip S was reduced to 60%. At the end of the rolling process, the strip S is in the form of a new type of hard, cold rolled tin plate which is now commercially available from a number of steel mills, e.g., from the US. Steel Corporation under the designation Ferrolite.

The 30% to 60% cold rolled plate or strip, as it comes from the cold reduction rollers of the steel mill, is relatively hard and brittle, and therefore is only suitable for limited field of usage by the can industry. However, it has a very great economic advantage, were the brittleness relieved by some operation. For every base box, i.e., 31,360 sq. in., which is coated with tin at a gauge, for example, of 0.012 inch, one obtains after cold rolling a total of two base boxes of tin coated steel 0.006 inch thick. The low cost of rolling is such that doubling the area of product is accomplished at a much lower cost than would otherwise be possible. The steel industry has recognized the lower cost per unit of this hard rolled tin plate or strip, as compared to the conventional tin plate or strip, by pricing it at per base box below that of conventional plate of the same gauge. Since the hard rolled plate is much stronger than conventional plate, one can use a thinner gauge of the hard roller plate with a further increment of savings of materials cost amounting to 15 per box for every reduction in gauge of 0.00055 inch. A potential savings to the can industry by the use of the hard rolled plate adds up to many millions of dollars. However, the full utilization of such plate, and obtainment of related savings of metal costs, depends on the improvement in ductility of such hard and brittle plate which may be obtained by the use of the apparatus of this invention.

There is another equally or perhaps more important field of application of this invention. The hard rolled tin plate or strip referred to thus far has started as hot rolled steel strip which is cold rolled by to to perhaps double the final gauge, then annealed, coated with tin and again cold rolled to a final gauge. It is possible instead to cold roll hot rolled strip directly to final gauge in a five or six stand tandem rolling mill. The cold reduction of 80% to results in extremely hard and strong steel strip which ordinarily is far too brittle to be used in the unannealed state. However, by partially restoring the ductility of such material with the practice of this invention, it could be employed for many purposes in the hard, unannealed state, either as is or with a subsequently applied tin coating or thin coating of other metal or material.

The high strength of the extremely hard rolled steel makes possible further reductions in gauge of metal for many fields of utilization, e.g., closures for cans. Not only are there substantial savings in amount of material, but the elimination of annealing and conventional temper" rolling results in appreciable savings of process cost in the production of this hard rolled metal strip. While an appreciable savings in cost is expected, the exact cost savings is not yet known, because, until the present invention, there has been no way of utilizing such very hard and brittle plate and therefore the product has not been made nor priced commercially. Although the apparatus of this invention is primarily intended for use in conjunction with the above described steel strips, it may also be used in conditioning other work hardened metals including aluminum, brass, copper, etc.

In accordance with this invention, either of these two types of hard rolled plate or strip or any other type of hard, brittle plate or strip may be further worked upon as part of the continuous forming thereof in the steel mill, or the plate or strip may be coiled subsequent to the cold reduction operation thereof and later worked upon in accordance with the invention either at the steel mill or at the can makers plant. For purposes of convenience, the working of the hard and strong but brittle cold rolled plate or strip S in accordance with the invention has been illustrated with the strip S being supplied in coil form.

The apparatus 8, for illustration purposes, is shown as including a base 12 which may be of any desired construction. The base 12 has a plurality of longitudinally spaced supports 13 extending upwardly from the sides thereof and supporting a lower guide 14. It is to be noted that the undersurface of the lower guide 14 is spacedabove the base 12 to provide the necessary clearance for a lower roller' assembly to be described in detail hereinafter, the lower roller assembly being entrained over the lower guide 14 and being generally referred to be the 'numeral 15.

At each end of the lower guide 14 there is a horizontally disposed, transversely extending drive shaft 16. Each drive shaft 16 is supported by a pair of bearing assemblies 17, the bearing assembly 17 being, in turn, supported by support member 18 secured to opposite sides of the guide 14 and projecting longitudinally therefrom. Each drive shaft 16 carries a sprocket assembly, generally referred to by the numeral 19.

Suitable supports 20 extend upwardly from opposite sides of the base 12 and are connected together at their upperends by transverse frame members 21. The transverse frame members 21 support a hydraulic lift assembly, generally referred to by the numeral 22. The lift assembly 22 is schematically illustrated as including a cylinder 23 carried by the frame members 21, and a piston 24 within the cylinder 23, the piston 24 having a large piston rod 25 projecting downwardly out of the cylinder 23 and secured to an upper frame member 26 by means of a support flange 27'.

The upper frame member 26 serves both as a guard for an upper roller assembly, generally referred to by the numeral 27, and as a support for an upper guide 28, the guide 28 being suspended from the frame member 26 by means of supports 29. At this time, it is pointed out that the upper guide 28 is identical with the lower guide 14 and is provided with a pair of drive shafts 30 mounted at opposite ends thereof. The drive shafts 30 are supported in bearing units 31 which, in turn, are carried by longitudinally extending supports 32 secured to opposite sides of the upper guide 28. Each of the shafts 30 supports a sprocket assembly, generally referred to by the numeral 33, the sprocket assemblies 33' supporting the upper roller assembly 27 and driving the same. It is to be understood that the upper roller assembly 27 will be formed identically with the lower roller assembly 15.

Reference is now made to FIGURE 5 in detail, Wherein there is shown a portion of the lower roller assembly 15. The roller assembly is formed of a plurality of transverse rollers 34, each of which extends the full width of the lower roller assembly 15. The rollers 34 are connected together by links 35 disposed at the opposite ends of the rollers 34. The links 35 join together two adjacent rollers 34 and the links 35 are disposed in rows with links 35 of adjacent rollers being disposed in alternating lapped relation. Each of the rollers has an integral end extension 36 of a reduced diameter and each link is provided with a pair of bearings 37 in each of which a reduced diameter extension 36 of a roller 37 is journaled. If desired, the bearings 37 may be simply in the form of accurate bores in the links 35. Also, while the ends of the extensions 36 have been illustrated as being riveted, the links 35 may be secured to the extensions 36 by means of washers and either snap pins or snap links, as is customary in roller chain construction. Depending upon the requirements of the apparatus 8, the rollers 34 will have diameters ranging from inch to /2 inch. Each of the links has a projecting guide portion 38 for engagement with the edges of guide 14 in the case of the lower roller assembly 15.

At this time, it is again pointed out that the upper roller assembly 27 is of a construction identical to the roller assembly 15 and is therefore not described in detail here.

Reference is noW made to FIGURES l and 4 of the drawings wherein it is shown that the

guides

14 and 28 have opposed guide surfaces 39 and 40, respectively. The guide surface 39 has the rollers 34 engaged therewith for the purpose of transmitting radial forces imposed upon the rollers 34 to the guide surface 39. The guide surface 40 has the rollers 34 of the upper roller assembly 27 engaged therewith for receiving radial forces applied to the rollers of the upper assembly 27.

The guide surfaces 39, 40 have widths corresponding to the lengths of the rollers 34, as is best shown in FIG- URE 2. As a result, the innermost links .35 of the sets of links disposed at opposite ends of the rollers 34 run alongside the edges of the

guides

14, 28 and maintain the

roller assemblies

15, 17 in alignment with the

guides

14, 28.

The sprocket assemblies 19 and 32 being identical, only the sprocket assembly 19 will be described in detail here. As is best shown in FIGURES 3 and 4, the sprocket assembly 19 is formed of a plurality of sprockets 41 spaced along the drive shaft 16 with the sprockets 41 being spaced apart by sprocket spacers 42 also carried by the shaft 16. It is to. be noted that each of the sprockets 41 is provided with notches 44 of a configuration to receive the rollers 34. In this manner, the sprockets are interlocked with the roller assembly 15.

Attention is now directed to FIGURE 3, wherein it is pointed out that in addition to the supports 18 carrying the bearings 17, the guide 14 is provided with intermediate stub supports 45 which project in between adjacent sprockets 41 and overlie the shaft 16 to provide a suitable guide surface for the rollers 34 passing from the sprockets 41 onto the guide surface 39. The stub supports 45 provide the load carrying capacity required to flex the strip S as it enters the apparatus 8 and minimize the bearing loads on the

shafts

16 and 30 at the entering end of the apparatus 8 by supporting the rollers 34 so that their load is not transmitted to the sprockets on the

shafts

16 and 30. If desired, the sprocket spacers 42 could. be eliminated or modified and the stub supports 45 provided with suitable bearing means which, when so provided, would support the shafts 16 intermediate the spaced sprockets 41 to prevent flexing of the shafts 16 due to the loads imposed thereupon. The guide 28 could be similarly formed.

The apparatus 8 also includes an electric drive motor 46 which may be of any type and which is coupled to a longitudinally extending drive shaft 47 which extends alongside one side of the base 12. The drive shaft 47 is carried by suitable bearing means 48 mounted on the base 12. The drive shaft 47 is provided at opposite ends thereof with Worms 49 which are meshed with worm wheels 50 on the ends of the shafts 16, as is best shown in FIGURE 2. In this manner, the two sprocket assemblies 19 are driven in unison.

The sprocket assemblies 33 are driven by gears 51 mounted on the shafts 30 and meshed with the gears 50. However, it is to be noted that the sprocket assemblies 33 are slightly out of rotational phase with the sprocket assemblies 19 so that the opposed portions of the roller assemblies 15and 27 are out of phase onehalf of the spacing between a pair of rollers 34. in this manner, the rollers 34 of the two

roller assemblies

15 and 27 may be disposed in meshed relation so as to define a wave-like path for the strip S between the op posed runs of the

roller assemblies

15 and 27.

It is pointed out that the gears 51}, 51 are of such size so as to permit the proper intermeshing of the rollers of the

roller assemblies

15 and 27. When a greater or lesser intermeshing is desired, the gears t} and 51 may be replaced. There are, of course, other gear assemblies which could be utilized to permit adjustment of the intermeshing of the two

roller assemblies

15 and 27. Such an example gear arrangement (not shown) would include idler gears or chain and sprocket drives of conventional types.

Reference is directed to FIGURE 4 in particular wherein it will be apparent that the strip S must be engaged with two rollers 34, one each of each of the

roller assemblies

15 and 27, to obtain a complete flexure of the strip S as it passes between these two rollers and is flexed first one way on the first roller and then reverse flexed on the second roller, each succeeding pair of rollers producing a complete flexure of the strip S as it passes between

the'roller assemblies

15 and 27.

lit will be understood that as the strip S passes between the opposed runs of the

roller assemblies

15 and 27, not only will the strip S be flexed by the initial engagement thereof by the

roller assemblies

15 and 27, but due to the fact that the rollers 34 will rotate through their rolling engagement with the guide surfaces 39 and 40, the movement of the strip S relative to the

guides

14 and 28 will be twice that of the axes of the rollers in'roller

assemblies

15 and 27, with the result that the strip will be fed between the

roller assemblies

15 and 27 to obtain the desired reverse flexing thereof and the flexing of the strip S will be continuous. It is the movement of the rollers 34 relative to the guide surfaces 39 and 44 that requires twice the number of rollers to effect the required number of complete flexures since the rollers 34 move at one half the speed of the strip S relative to guide surfaces 39 and 4t}, and therefore only half as many complete flexures are accomplished in a given length of guide surface.

Any number of flexures provided by the apparatus 8 must be within practical limits in order to permit the apparatus 8 to be of a sufliciently small size to be economically feasible. It is to be understood, however, that the number of rollers of the

roller assemblies

15 or 27 engaged with the strip S and the diameters of the rollers 34 must be such as to produce more than a mere roller leveling of the strip S. As the hard, cold rolled strip S passes around the rollers of the

roller assemblies

15 and 27, it must be stressed to the extent that at least that surface layer of the strip S in tension remote from the particular roller assembly is stressed well beyond the yield strength of the metal of the hard rolled strip S. Further, in the working of the hard, cold rolled tin plate or strip having severely cold worked steel substrate as the base thereof, the surface layer of the steel strip under compression is also stressed Well beyond the yield strength of the metal of the strip S. Tests have indicated that the metal should be stressed beyond its yield strength to a depth of from to 40% of the thickness of the strip S .inwardly from each stressed facing layer thereof. Of course, the deeper the penetration of work within the range specified, the fewer are the number of cycles of reverse stress required to obtain the desired increase in ductility, but flexing must obviously be stopped prior to the initiation of any fatigue damage.

For any given number of cycles of reverse flexing, e.g., 10 or 100 or 1,000, there will be a stress below the ultimate tensile strength which will be sufficient to cause fracture after the specified number of cycles of stressing. For the same number of cycles of stress, there will be a lower stress at which no visible fracture occurs but at which microcracks are formed'which would ultimately cause fracture. The line of stress to cause microcracks versus the number of cycles to form these at each stress is called a damage curve. It is requisite, in the practice of this invention, that the number of cycles of stressing the surface layers beyond their yield strength by flexure should be less than the number of cycles to cause damage at the stress caused by that flexure. Ductility is increased by this invention when the combination of number of cycles of flexure and maximum flexural stress are so related that no fatigue damage occurs.

In test apparatus, it has been found that increase in ductility of the strip of hard, cold rolled tin plate in going. from one to ten cycles of flexure was approximately equal to the increase of going from 10 to passes. Thus, while in general there was a continuing benefit, the benefit corresponded to the logarithmic increases in number of passes. From a commercial standpoint, it is believed that approximately 100 complete cycles of reverse flexing is the most economically feasible number considering results in the way of increase in ductility of the strip and the machinery required for obtaining an increased number of cycles of reverse flcxure. This would require the engagement of the strip S with on the order of 400 of the. rollers 34 as the stripv S passes through the apparatus 8. This will require on the order of 200 rollers 34 in engagement with each of the guide surfaces 39, 40 at all times.

The apparatus 8 is particularly adaptable to the required reverse flexing of relatively thin strip, such as the strip S, in that adequate support can be obtained for the very small diameter rollers so that a relatively severe flexing of the strip S can be obtained and at the same time the apparatus 8 is relatively compact so that the desired reverse flexing can be obtained in a relatively short distance. In addition, the rollers are not continuously engaged with the strip S so as to permit dissipation of heat which may be involved dueto the rolling contact of the rollers 34 with both the strip S and the guide surfaces 39 and 40.

From the foregoing, it will be seen that novel and advantageous provision has been made for carrying out the desired end. However, attention is directed to the fact that variations may be made in the example apparatus disclosed herein without departing from the spirit and scope of the invention, as defined in the appended claims.

I claim: 1

1. An apparatus to achieve multiple reverse flexing of work hardened continuous metal strip to increase the ability thereof to withstand fabrication by increasing the ductility thereof, said apparatus comprising a pair of elongated guides having opposed race surfaces, a continuous roller assembly including a plurality of rollers entrained about each of said guides, drive meansengaged with said roller assemblies for driving said roller assemblies in unison and with rollers of said roller assemblies in staggered relation, means connected to one of said guides for moving said one guide vertically relative to the other of said guides and retaining said one guide vertically in an adjusted position relative to said other guide, each of said rollers being of a diameter ranging from Ms to /2 inch.

2. An apparatus to achieve multiple reverse flexing of:

work hardened continuous steel strip to increase the ability thereof to withstand fabrication by increasing the ductility thereof, said apparatus comprising a pair of elongated guides having opposed race surfaces, a continuous roller assembly including a plurality of rollers entrained about each of said guides, drive means engaged with said roller assemblies for driving said roller assemblies in unison and with rollers of said roller assemblies in staggered relation, means connected to one of said guides for moving said one guide vertically relative to the other of said guides and retaining said one guide vertically in an adjusted position relative to said other guide, each of said rollers being substantially A inch in diameter.

3. An apparatus to achieve multiple reverse flexing of work hardened continuous steel strip to increase the ability thereof to withstand fabrication by increasing the duetility thereof, said apparatus comprising a pair of elongated guides having opposed race surfaces, a continuous roller assembly including a plurality of rollers entrained about each of said guides, drive means engaged with said roller assemblies for driving said roller assemblies in uni son and with rollers of said roller assemblies in staggered relation, means connected to one of said guides for moving said one guide vertically relative to the other of said guides and retaining said one guide vertically in an adjusted position relative to said other guide, each of said roller assemblies being formed of a plurality of transverse rollers, links arranged in rows at opposite ends of said rollers and connecting together said rollers in an endless assembly, said links being confined by said guides against movement in a direction transverse to the elongated guides but being freely movable in a direction parallel to the elongated guides thereby maintaining alignment of said roller assemblies with said guides, and said drive means including multiple sprockets disposed at opposite ends of each of said guides, each of said sprockets having pockets receiving said rollers.

4. An apparatus to achieve multiple reverse flexing of work hardened continuous metal strip to increase the ability thereof to withstand fabrication by increasing the ductility thereof, said apparatus comprising a pair of elongated guides having opposed race surfaces, a continuous roller assembly including a plurality of rollers entrained about each of said guides, drive means engaged with said roller assemblies for driving said roller assemblies in unison and with rollers of said roller assemblies in sta-ggered relation, means connected to one of said guides for moving said one guide vertically relative to the other of said guides and retaining said one guide vertically in an adjusted position relative to said other guide, there being on the order of 200 rollers engaged with each race surface.

5. An apparatus to achieve multiple reverse flexing of work hardened continuous metal strip to increase the ability thereof to withstand fabrication by increasing the ductility thereof, said apparatus comprising a pair of elongated guides having opposed race surfaces, a continuous roller assembly including a plurality of rollers entrained about each of said guides, drive means engaged with said roller assemblies for driving said roller assemblies in unison and with rollers of said roller assemblies in staggered relation, means connected to one of said guides for moving said one guide vertically relative to the other of said guides and retaining said one guide vertically in an adjusted position relative to said other guide, there being on the order of 200 rollers engaged with each race surface, each of said rollers being of a diameter ranging from A3 inch to /2 inch.

6. An apparatus to achieve multiple reverse flexing of work hardened continuous metal strip to increase the ability thereof to withstand fabrication by increasing the ductility thereof, said apparatus comprising a pair of elongatedlguides having opposed race surfaces, a continuous roller assembly including a plurality of rollers entrained about each of said guides, drive means engaged with said roller assemblies for driving said roller assemblies in unison and with rollers of said roller assemblies in staggered relation, means connected to one of said guides for moving said one guide vertically relative to the other of said guides and retaining said one guide vertically in an ad justed position relative to said other guide, there being on the order of 200 rollers engaged with each race surface, each of said rollers being substantially A inch in diameter.

7. An apparatus to achieve multiple reverse flexing of work hardened continuous metal strip to increase the abil ity thereof to withstand fabrication by increasing the ductility thereof, said apparatus comprising a pair of elongated guides having opposed race surfaces, a continuous roller assembly including a plurality of rollers entrained about each of said guides, drive means engaged with said roller assemblies for driving said roller assemblies in unison with said rollers of said roller assemblies in staggered relation, and each of said rollers being of a diameter ranging from /8 to /2 inch.

8. An apparatus to achieve multiple reverse flexing of work hardened continuous metal strip to increase the ability thereof to withstand fabrication by increasing the ductility thereof, said apparatus comprising a pair of elongated guides having opposed race surfaces, a continuous roller assembly including a plurality of rollers entrained about each of said guides, drive means engaged with said roller assemblies for driving said roller assemblies in unison and with rollers of said roller assemblies in staggered relation, and there being on the order of two hundred rollers engaged with each race surface.

9. The apparatus as defined in claim 7 wherein said roller assemblies include a plurality of connecting links, and said links include guide means engaging associated ones of said elongated guides for guiding said roller assemblies in the movement thereof along said race surfaces.

10. The apparatus as defined in claim 8 wherein said roller assemblies include a plurality of connecting links and said links include guide means engaging associated ones of said elongated guides for guiding said roller assemblies in the movement thereof along said. race surfaces.

References Cited by the Examiner UNITED STATES PATENTS 2,391,419 12/1945 Holtz 153102 FOREIGN PATENTS 863,335 1/1953 Germany. 834,206 5/1960 Great Britain.

CHARLES W. LANHAM, Primary Examiner.

WHITMORE A. WILTZ, MICHAEL V. BRINDISI,

Examiners.

Claims

1. AN APPARATUS TO ACHIEVE MULTIPLE REVERSE FLEXING OF WORK HARDENED CONTINUOUS METAL STRIP TO INCREASE THE ABILITY THEREOF TO WITHSTAND FABRICATION BY INCREASING THE DUCTILITY THEREOF, SAID APPARATUS COMPRISING A PAIR OF ELONGATED GUIDES HAVING OPPOSED RACE SURFACES, A CONTINUOUS ROLLER ASSEMBLY INCLUDING A PLURALITY OR ROLLERS ENTRAINED ABOUT EACH OF SAID GUIDES, DRIVE MEANS ENGAGED WITH SAID ROLLER ASSEMBLIES FOR DRIVING SAID ROLLER ASSEMBLIES IN UNISON AND WITH ROLLERS OF SAID ROLLER ASSEMBLIES IN STAGGERED RELATION, MEANS CONNECTED TO ONE OF SAID GUIDES FOR MOVING SAID ONE GUIDE VERTICALLY RELATIVE TO THE OTHER OF SAID GIDES AND RETAINING SAID ONE GUIDE VERTICALLY IN AN ADJUSTED POSITION RELATIVE TO SAID OTHER GUIDE EACH OF SAID ROLLERS BEING OF A DIAMETER RANGING FROM 1/8 TO 1/2 INCH.