US2326715A - Manufacture of center stretched strip - Google Patents

Description

g- 1943- v L. L. WILSON ETAL 2,326,715

MANUFACTURE OF CENTER STRETCHED STRIPS Filed Feb. 15, 1941 2 sheets-Sheet 1 L10 d L. Wilson 114m .Qflazwelll, flibla d W lea miller Patented Aug. 10, 1943 CENTER s'rnn'ronnn s'rm Lloyd L. Wilson, Sharpsville, and Harold W; Lowmiller, Farrell, Pa, and Maxwell L. Bible, Masury, Ohio, assignors to Sharon Steel Cora "MANUFACTURE OF :poration, Sharon, Pa.,

sylvania a corporation at Penn- Application February 13, 1941, Serial No, 378328 10 Claims.

The invention relates to the manufacture of thin, flexible strip having sufficient stifiness and resiliency to snap backer restore itself to its original position when flexed. s

More particularly, the invention relates to the manufacture of thin flexible metal strip adapted to maintain itself in a longitudinally straight condition when supported over a relatively long span, and to restore itself to said straight condition when bumped or otherwise flexed between pports.

One example of \a use for such strip is the slats in Venetian blinds, wherein slats of thin metal strip are supported over a span of approximately thirty-three inches, and may be curved or bent laterally to a desired shape but are required to be normally straight longitudinally and to snap back or return themselves to said straight condition when flexed or bumped.

It has been found thata Venetian blind slat of A further object is to provide a novel method of continuously roller stretching the center of a thin metal strip longitudinally,

Likewise, it is an object of the present invention to provide a method of providing a center stretch in thin strip material without producing any permanent longitudinal bow in the material.

Another object is to provide a novel apparatus for continuously center stretching a strip longi tudinally thereof without requiring the use of.

drawing dies.

A. further object is to provide a novel arrangement of convex'rolls for center stretching a metal strip when passed successively thereover to produce a longitudinally straight and flat strip which may thereafter be laterally curved to have such stifines and. rigidity as to maintain itself in straight condition, and to restore itself to such thin metal strip made according to conventional practice hasa definitetendency to sag or bend longitudinally between supports, and when curved laterally by forming between mating convex and concave rolls, this longitudinal bending may ocour in the direction of the lateral curve in which case it is called down bow, or in theopposite direction in which case it is called back bow.,

It has been found also that the down bow and V back bow can. be controlled by longitudinally stretching the center of the strip .prior'to the lateral forming operation to produce a slat which will maintain itself in a straight condition longitudinally over a given span of approximately tlnrty-three-inches, and-which when flexed will restore itself or snap back to said straight condition.

Prior to our invention, the required longitudinal center stretchingof the strip has been, accomplished by drawing a strip through draw blocks or dies prior to the lateral curving orforming operation. However, this drawing operationproduces scratches on the surface of the strip unless the drawing dies are carefully and thoroughly cleaned at frequent intervals, which adds materially to the time and expense of the center stretching operation.

condition when flexed.

These and other objectsare attained by the novel method and apparatus comprising the present invention, which is shown by way of example in the accompanying drawings and hereinafter described in detail and defined in the appended claims.

The present novel method may be stated in general terms as including roller stretching the center of the continuous strip longitudinally by pulling the strip in a sinuous path past and in contact with one after another of a series of convex rolls, and wrapping the'strip around a substantial portion of the periphery of certain of said rolls, while maintaining the tension on th strip substantially equal at all of the rolls.

The present novel a paratus may be stated in general terms as including a frame, a series of convex rolls jouinaleddn said frame, means for pulling a continuous strip in a sinuous path successively past and in contact with said rolls, cer tain of, said rolls being so located with respect to other rolls as to cause th strip to wrap around a substantial portion of r theperiphery of said We have invented a novel method and apparatus for center stretching thin metal strip so as to eliminate the use of drawing dies and their attendant disadvantages. i V a It is therefore an object of the present invention to provide a novel and economical method of producing a center stretched metal strip without-surface scratches.

certain rolls, and certain of said rolls being Journaled in bearings having floating mountings in the frame whereby the tensioned pull on the stripadjusts the location of said floating rolls with respect to other of said rolls so that the tension on the strip is substantially equal at all of said rolls.

Referring to thedrawings forming part hereof,

Figure 1 is a diagrammatic view in longitudinal section of the novel apparatus for center stretching a continuous strip;

Fig. 2 is an enlarged cross sectional view of thestrip prior to its passing through the edge rolls; Fig. 3 is a fragmentary sectional view through the strip at the edge rolls;

Fig. 4 is an enlarged side elevation of the frame of the apparatus, showing the manner of sec- Fig. 8 is an enlarged sectional view as on line- 8-8, Fig. 4.

Similar numerals refer to similar parts throughout the drawings.

Roll is is mounted substantially directly below roll I2 and is provided with a vertically floating mounting. Preferably the end bearing plates 29 for the roll l3 are provided with grooves 30 at their side edges slidably engaging the'edge portions 25 of the'side plates l8 sothat the roll I3 is free to move up and down in the slot 23, itsa position being determined by the amount of teneter and location of roll I 3 is such'as to directthe strip downwardly and rearwardly from A thin continuous strip to be center stretched longitudinally is'indicated at 1, and may be strip steel, although the invention may be applied to strips of other materials. The strip 1 is pulled through the improved center stretching apparatus by means of a usual coiler or take-off reel indicated diagrammatically at 1 8, for imposing a tensioned pull on the strip.

The novel center stretching apparatus is indicated generally at 9, and at the entrance side thereof combined centering, guide and edge rolls indicated at ID are provided for removing the sharp edges or burrs from the side edges of the strip and for centering and guiding the strip into the stretching apparatus 9. These edging rolls preferably have tapered or V-shaped annular grooves lila into which the edge of the strip is entered for being edge rolled and guided.

Wipers 1017 may be interposed between the rolls l0 and stretching apparatus 9 to remove dirt and dust from the strip and may be adjust-' ed for back tensioning the strip if desired.

As shown in Fig. 1 the center stretching appa ratus 9 includes a plurality of rolls ll, l2, 13, M, i5, i6 and I! over which the strip 1 passes successively, and as shown in Figs. 5 to 8 inclusive, all of these rolls except i! have convexly curved peripheries or outer rollingsurfaces. Roll I1 is a cylindrical roll and has a fiat rolling surface.

As shown, the rolls are journaled in side frame plates i8 and are irregularly staggered with respect to each other, so that the strip Tin passing over and around and in contact with the rolls follows a sinuous and irregular path. Rolls H, H and i! are journaled in fixed bearings I9, 28

and 2| respectively secured to the side plates l8 in a usual fashion.

Roll I2 is located above the level and forwardly of roll ii, and is preferably journaled in end bearingplates 22 which are vertically adjustable in the side plates l8. Preferably, the side plates l8 are slotted'vertically as indicated at 23 and i the bearing plates 22 are provided with end grooves 24 slidably engaging the edge portions 25 of side plates l8 defining the slotted opening 23'. Means-for vertically adjusting the bearing plates 22 may include a transverse movable plate 26 connecting the end bearing plates 22 and.

sion on the strip 1 which wraps around a portion of the periphery of said roll l3. The diamroll l2.

Roll 14 is located in a position spaced from and forwardlyof roll l3 for'directing the strip forwardly and slightly downwardly from roll l3. Roll I5 is provided with a horizontal floating mounting in the side plates l8, and as shown the roll, [5 is located rearwardly of roll l4 and above the same for directing the strip upwardly and rearwardly from roll It. .The end bearing-plates 3| for the roll l5 are provided with grooves 32 at their top and-bottom edges, which grooves slidably engage the top and bottom edges 33 of a horizontal slot 34 formed in the side plates l8, so that the roll l5 has a horizontal floating mounting similar to the vertical floating mounting of roll l3, its position being determined by the tension on the strip lwvhich wraps around 4 approximately half of the periphery of the roll.

Roll I6 is located forwardly of roll l5 for directing the strip downwardly and forwardly from roll i5. Roll l6 preferably has a horizontally adjustable mounting similar to the vertically adjustable mounting of roll I 2. The end bearing plates 35 for roll l6 preferably are provided with grooves 36 at their top and bottom edges slidably engagingthe top and bottom edges 33 of the side plates I8which definethe slot 34.

i8 and is connected to the end bearing plates 35, and an adjusting screw 38 is rotatably secured at one end in the transverse plate 3'l-and threaded through a fixed plate 49 extending transversely between and secured to the ends of rthe side' tact with roll H and then upwardly over and with its lower surface in contact with 'roll [2 and then downwardly and rearwardly around and with its upper surface in contact with roll [3.

The relative sizes and locations of rolls ll, I2

and [3 are such that the strip wraps around a substantial portion ofthe periphery of roll I 2,

said portion being approximately half of the periphery of said roll.

From under the floating-roll 13, the strip passes forwardly under and around fixed roll M- with its upper surface in contact with a portion of the periphery thereof and thence upwardly and rearwardly to wrap around and over fl0atl ng.r01ll5 with its lower surface in contact with a substantial portion thereof, and then downwardly and forwardly under and with its upper surface in contact with roll l6, from which it passes under and with its upper surface in'contact with cylindrical roll 11 and thence to the take off reel 8. The relative sizes and locations of rolls l4, l5. and I6 are such as to cause the strip to wrap around a substantial portion of the periphery of floating roll l5, and in the illustrated positions of the rolls the strip wraps around slightly less than half of the periphery of floating roll '|5.-

The several rolls of the novel apparatus have A transverse movable plate 31 extends between the side plates in the drawings, we have found that best results are obtained by making the rolls of the following specific diameters (measured at center of roll face) and specific radii of convex curvature:

Radius of Roll Diameter curvature Inches Inches 1. 490 10 l. 470 16 2. 992 l 1. 465 20- 900 12 2. 990 24 2 Flat The tensioning pull on the strip 1 causes the floating rolls [3 and [5 to automatically adjust their positions to equalize the tension on the strip and control the direction of the strip between the fixed rolls adjacent thereto, and when the rolls l2 and I6 are adjusted by means of screws .2?

center of a. center stretched strip andvisibly' and audibly noting the snap occurring .in. the strip.

- With the present improved method and appa- I ratus, we have found that metallic strip which has been coated; such as .for example galvanized,

- tin coated, terne coated, and painted strip steel,

can be satisfactorily center stretched. This due to the fact that the stretching is done entirely by rolling -contact, whereas any prior center stretching methods and apparatus'of which we are aware cause a dragon the coating and produce scratches and the like on the surface of the strip.

The novel method and apparatus of the present invention provides a novel and economical 'method of producing longitudinally center stretched strip which is free from surface scratches, without requiring the use of drawing dies, such strip after being subsequently laterally curved having sufiicient stiffness and rigidity to maintain itself inlongitudinally straight condition and to restore itself or snap back to such condition when flexed. i

We claim: 1. Apparatus for center stretching a strip longitudinally thereof including a frame having laterally spaced side plates, a series of irregularly staggered convex rolls journal'ed at their ends in said side plates, means for pulling a' continuous strip in a sinuous path successively past said rolls with its upper surface in contact with cer- .t-ain of said rolls and with its lower surface in.

- contact with others of said rolls, ;and floating and 38 respectively, the floating rolls l3 and i5 will change their positions accordingly under the tension on the strip to equalize the tension on the strip between the next preceding and following rolls, that is', floating roll l3 equalizes the tension between fixed rolls [2 and i l, and floating roll l5 equalizes the tension between fixed rolls Id and I5.

Accordingto the present invention, thin metal strip having the desiredamount of center stretch and after being subsequently laterally .curved, having the corresponding snap back and stiffening characteristics, has been produced in actual.

practice by pulling the same through the novel apparatus shown and in the manner described herein.

The degree of convex curvature of the various rolls in combination with the amount of wrapping around the peripheries of certain of the rolls due to their relative sizes and locations is largely responsible for producing the required amount of center stretclnng in the strip. This amount of center stretching can be varied by adjusting the location of the adjustable rolls l2 or it and by varying the size or degree of convex curvature of one or more of the rolls.

Moreover, an increment of the stretch occurs in each strip portion extending between each successive pair of rolls, and particularly between rolls l2 and i3, i5 and i5, and i5 and it, s e

strip is being pulled past and in contact with the rolls under tension. Also an increment of the total center stretch occurs in the portion of the strip which is in contact with each roll and particularly at rolls l2, i3, i5 and iii. The sum' or total of these stretch increments equals the total amount .of center stretch imparted to the strip.

As the total amount of center stretch is a minute quantity and difiicult to measure, no exact value of the same can be stated. However, its existence in the strip is evident by pressing the mountings in said side plates for certain of said rolls whereby-the tensioned pull on the strip adjusts the location of saidfioating rolls with ,respect to the non-floating rolls to control the direction and equalize the'tension on the strip between said non-floating rolls. 1

2. Apparatus for center-stretching 'a strip longitudinallyv thereof including a frame having laterally spaced side plates, a series of irregularlystaggered convex rolls journaled at their ends in said side plates, means for pulling a continuous strip in a sinuous path successively past said rolls with itsupper surface in contact with certain of said rolls and with its lower surface in contactwith'others of said rolls, certain of said rolls being so located with respect to others of said rolls as to cause the strip to wrap around a substantial portion of at least one roll'tc substantially reverse the direction of thepath of the strip at said one roll, and floating mountings in said side plates for certain of said rolls wherebythe tensioned pull on the strip adjusts the location of said floating rolls with respect to the non floating rolls to control the direction and equalize the tension on the strip between said.

non-floating rolls.

3. Apparatus fo center stretching a strip longitudinally thereof including a frame having laterally spaced side plates, a series of irregularly staggered convex rolls journaled at their ends in said side plates, means for pulling a continuous strip in a sinuous path successively pastsaid roll-s with its upper surface in contact with'certain of said rolls and with its lower surface in contact with others of said. rolls, certain of saidrolls being so located with respect to iothers of said rollsas to cause the strip to'wrap its upper surface around one of said rolls to substantially reversethe direction of the path of the strip .at said one roll, and to wrap its lower surface around another of said rolls to substantially reverse the direction of the path of the strip at said other roll, and floating mountings -in said side plates for certain of said rolls whereby the tensioned pull on the strip adjusts the location of said floating rolls with respect to the non-floating rolls to control the direction and equalize the tension on the strip between said non-floating rolls.

4. Apparatus for center stretching a strip longitudinally thereof including a-frarne, a series of convex rolls journaledin said'frame, means for pulling a strip past and in. contact with one after another of said rolls, said series of rolls including a first roll for engaging the upper surface of said strip, a second roll journaled above and forwardly of said first roll for engaging the lower surface or said strip, a third roll spaced below said second rollfor engaging the upper. surface of said strip and directing the strip down- 'ward1y,and* rearwardly from said second roll,

means providing a vertically floating journal mounting for said third roll, a fourth roll jourstrip downwardly and forwardly.

vertically floating journal mounting ,for said second roll,a third roll spaced above and forwardly of aid second roll for engaging the lower surface of said strip and directing the strip upwardly, means providing a horizontally floating mounting for said third roll, and a fourth roll journaled forwardly of said third roll for engaging the upper surface of said strip and directing it downwardly from said third roll.

'7. Apparatus for center stretching a strip longitudinally thereof including a frame, a series of convex rollsljournaled in said frame, means for pulling a strip past and in contact with one after another of said rolls, said series of rolls including a roll having a maximum diameter of 1.47 and a radius of convex curvature of, 16 for engaging the lower surface of said strip, a second roll said strip and directing the strip downwardly 5. Apparatus for center stretching a strip longitudinallythereof including a frame, a series "of convex rolls journaled in said frame, means for pulling a strip past and in contact with one after a first roll having a maximum diameter of 1.49"

and rearwardly from said first roll, means providing a vertically floating journal mounting for providing a horizontally floating journal mounting for said third roll, and a fourth rollhaving a maximum diameter of 2.990" and a radius of convex curvature of 24" journaled forwardly of said third roll for engaging the upper surface of said strip and directing it downwardly from another of said rolls, said series of rolls including and a radius of convex curvature of for en gaging the upper surface .of said strip, a second roll havinga maximum diameter of 1.47" and a maximum diameter" of 2.992" anda radius of convex curvature of 10" spaced below said second "roll for engagingjhe upper surface of said strip and directing the strip downwardly and rear- .wardly from aid second roll, means'providing a vertically floating journal mounting for said third roll, 'a fourth roll having a maximum ture of. 20 jogirn'aled forwardly-of said third roll for engaging the upper surface of said strip, a

fifth roll having a maximum diameter of .900 and a radius of convex curvature of 12" spaced above and rearwardly of said fourth roll for engaging the lower surface of said strip and directing the strip upwardly and rearwardly from said fourth roll, means providing a horizontally floating journal mounting for said fifth roll, and

a sixth roll having a maximum diameter of 2.990" and a radius of convex curvature of 24" spaced forwardly of said fifth rollfor engaging the upper surface of 'said strip and directing the strip downwardly and forwardly,

' -6. Apparatus for center stretching a strip .longitudinally thereof including a frame, a series of convex rolls-journaled in said frame, means for pullinga strip past 'andin contact with one after another of said rolls, said series of rolls including a roll for engaging the lower surface of said strip, a second roll spacedbelow said first roll for engaging the upper surface of said strip and .directingthe strip downwardly and rearwardly from said first roll, means providing a said third roll. 1 1

8. The method of continuously longitudinally center stretching a-strip to impart a permanent longitudinal center stretchtherein, which includes continuousi klooping the strip under tension substantially pon itself in alternately opposite directions,, maintaining 'the strip laterally curved as it is being looped, andyieldingly dediameter of 1.465"'and a radius of convex curva-" .flecting the path of the strip between said loops' to equalize the tension on the strip between said loops and to longitudinally stretch the center of the strip.

9. The method of continuously longitudinally jcenter stretchinga strip to impart a longitudinal center stretch therein, which includes continuously looping the strip under tension alternately in substantially opposite directions while maintaining thestrip laterally curved, and yieldingly deflecting the path of the strip between said with certain of said rolls and with its lower surface in contact with others of said rolls, and floating mountings in said frame for certain of said rolls whereby the tensioned pull on the strip adjusts the location of said floating rolls with respect to the non-floating 'rolls to control the direction and equalize the tension on the strip between said non-floating rolls.

LLOYD W. WILSON; HAROLD W; LOWMILLER. MAXWELL L. BIBLE.

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