US2492909A

US2492909A - Louvered sheet material

Info

Publication number: US2492909A
Application number: US572327A
Authority: US
Inventors: Warp Harold
Original assignee: Flex-O-Glass Inc
Current assignee: Flex-O-Glass Inc
Priority date: 1945-01-11
Filing date: 1945-01-11
Publication date: 1949-12-27
Anticipated expiration: 1966-12-27

Description

D86. 27, 1949 WARP 2,492,909

LOUVERED SHEET MATERIAL Filed Jan. 11, 1945 Q 5 Sheets-Sheet 1 ,JF I l 27 16 INVENTOR.

- I 20 Harald B mM Dec. 27, 1949 H. WARP 2,492,909

LOUVERED SHEET MATERIAL Filed Jan. 11, 1945 3 Sheets-Sheet 2 474 [/3 INVENTOR.

yam/d Q 7 9, %m JMW Dec. 27,.1949 H. WARP LOUVERED SHEETMATERIAL Filed Jan. 11,1945 s Sheets-Sheet s I INVENTOR. f/(U'OLQ? v UNITED STATES PATENT OFFICE LOUVERED SHEET MATERIAL Harold Warp, Chicago, Ill., assignor to .Flex-O- Glass, Inc., a corporation of Illinois Application January 11, 1945, Serial No. 572,327 .7 Claims. (Cl. 98-121) The invention relates generally to louvered sheet material and, more particularly, to louvered sheet material of the general type disclosed and claimed in my U. S. Letters Patent No. 2,366,224, dated January 2, 1945.

One object of the invention is to provide louvered sheet material of improved construction with the openings in the material small enough to enable the material to be employed as an insect barring screen having the added advantage of also intercepting certain direct light rays, more particularly, the direct rays of the sun over certain periods of the day.

Another object of the invention is to provide sheet material of the character described which is of a sturdy construction yet composed of very thin stock, flexible and capable of being rolled to be suitable for use as screen, as conveyor belts in certain applications, and for other purposes.

Yet another object is to provide louvered sheet material composed of narrow elements cut from a solid sheet and turned out of the plane of the sheet, in which each element in transverse cross section has an angular shape designed to strengthen the same against bending while not objectionably reducing the admission of light through the sheet.

Still another object is to provide sheet mate rial, composed of columns of a plurality of narrow elements cut from a solid, thin sheet and twisted out of the plane of the sheet, with the strips of the sheet remaining between the columns of elements formed with undulations to strengthen the sheet and render it more resilient to bending out of the plane of the sheet.

A further object is to provide sheet material, formed by a plurality of columns of elements cut from a solid, thin sheet and twisted out of the plane of the sheet, in which the resultant sheet has a limited and resilient yieldabillty in the direction of the columns giving to the material, when employed as a screen, and when properly applied, a tautness rendering the material less subject to injury by being capable of absorbing certain shocks to which the material is subjected.

Still a further object is to provide sheet material, formed by a plurality of columns of elements cut from a solid, thin sheet and twisted out of the plane of the sheet in which the spacing of the elements in their final form may be less than the width of the elements.

Yet a further object is to provide louvered sheet material which is readily and conveniently patched.

Another object is to provide sheet material, formed by a plurality of columns of narrow, parallel elements cut from a solid, thin sheet and twisted out of the plane of the sheet, in which the elements of alternate columns are offset in the direction of the columns.

Yet another objectis to provide sheet material, formed by a plurality of columns of narrow, parallel elements cut from a solid, thin sheet and divided by narrow strips in which the elements are slightly inclined from a true perpendicular to the dividing strips. 1

Other objects and advantages will become" apparent from the following detailed description taken in connection with the accompanying drawings, in which:

Fig. 1 is an elevational view of a piece of sheet material formed in accordance with this invention. The portion of material shown in Fig. 1 is approximately twice actual size.

Fig. 2 is a fragmentary and greatly enlarged view of the material of Fig. 1. Fig. 2 shows the material approximately six times its normal size.

Fig. 3 is a longitudinal sectional view taken approximately along the line 3-3 of Fig. 2.

Fig. 4 is a longitudinal sectional view taken approximately along the line 4-4 of Fig. 2.

Fig. 5 is a transverse sectional view taken approximately along the line 5-5 of Fig. 2.

Fig. 6 is a view similar to Fig. 2 but showing a slightly modified form of louvered material.

Fig. 7 is a longitudinal sectional view taken approximately along the line |--1 of Fig. 6.

Fig. 8 is a longitudinal sectional view taken approximately along the line 88 of Fig. '7.

Fig. 9 is a view similar to Fig. 2 but showing a further slightly modified form of louvered material.

Fig. 10 is a greatly enlarged view of a portion of the dividing or supporting strip of Fig. 9.

Fig. 11 is a fragmentary sectional view taken approximately along the line ll-il of Fig. 10.

Fig. 12 is a fragmentary sectional view taken approximately along the line l2--I2 of Fig. 10.

Fig. 13 is a fragmentary sectional view taken approximately along the line |3-l3 of Fig. 10.

Fig. 14 is an elevational view of a sheet of material cut to form a modified form of louvered material but before twisting of the elements.

Fig. 15 is an elevational view of the material of Fig. 14 with the louvers twisted.

Shown in the drawings and hereinafter described for purposes of disclosure are a number of modified forms of the invention: It is contemplated, however, that still other modifications and variations of the invention may be made. It is not intended, therefore, that the invention is to be limited to the specific forms disclosed. On the contrary, it is intended to cover all modifications and alternative constructions falling within the spirit and scope of the invention as defined in the appended claims. 1

The invention contemplates the provision of a perforate sheet material adaptable primarily for use as insect barring screen for windows or similar light admitting openings, but also adaptable for use in a variety of other ways, such as conveyor belts for light-weight materials, visors, etc. The material comprises generally a plurality of narrow, parallel elements 20 disposed at an angle with the plane of the material so as to permit passage of air or light, or both, through the material while being capable of intercepting'certain direct light rays when properly positioned with respect to a light source. To the end that the material may be readily and economically manufactured yet be of sturdy construction, it is in the main formed as a unitary structure with the elements 20 die-cut and drawn or formed from a solid sheet 2|. Depending upon the purpose to be served or the use to which the material is to be put, the sheet from which it is formed may be of metal, of plastic, or possible even some other material, though metal lends itself most readily to formation of the material and thus will permit the material when made of metal to be most economically produced.

As best seen in Figs. 1 and 2, the sheet of mate-' rial is first out along parallel, uniformly spaced lines of equal length to form columns of the narrow elements 20 severed along their side edges but retained integral at their ends with dividing and supporting strips 22. Each element 20 is then twisted about its longitudinal center line out of the plane of the sheet to become disposed at an angle with the plane of the sheet, as best seen in Figs. 3 and 5. Inasmuch as the material is intended to find extensive use as screen for windows or the like, the elements 20 are here shown as making an angle something less than a right angle with the plane of the sheet, this having been found preferable for maximum admission of light and maximum vision through the material, while excluding the direct rays of the sun for the vital portion of the day. It is to be understood, however, that this is an arbitrary angle which might be varied to suit the particular 4 which the louvered material is made should have a certain degree of resiliency so that they will tend to assume their normal position if not too severely or sharply bent, and if it is not treated when in bent position with the intent of having it take a permanent set in that position. In the case of metal, it must be capable of withstanding a slight drawing operation which takes place at the ends of the elements when they are twisted out of the plane of the sheet.

With the elements 20 accounting for all of the material in a column, that is, with no material left between elements, the width of the elements 20, it will readily be appreciated, bears a definite relationship to the number per inch of such elements that may be cut from a sheet 2 I. Likewise, with the exceptions hereinafter pointed out, the

width of the elements also bears a relationship to the spacing of the elements when twisted out of the plane of the sheet. Thus by varying the width of the elements 20 the mesh of the resulting material may be varied just as the mesh of conventional, woven screen varies. The mesh of the conditions for which the material is to be employed without departing from the spirit of the invention.

Though the material may, as already stated, be employed in a variety of ways, an important use is as screen for windows, doors and other light admitting openings, and the material will, therefore, be described primarily in relation to that use. In order that the material, when employed as screen, may admit the maximum amount of light, the elements 20 should be of a thickness consistent, of course, with obtaining the necessary structural strength. The sheet 2| from which the material is made is, therefore, very thin, preferably on the order of Aim of an inch though, of course, this is an arbitrary dimension and may be departed from to a reasonable extent without departing from the spirit of the invention. This dimension, moreover, is likely to vary somewhat depending upon whether the material is made of metal, plastic, or some other composition. The sheets from material may thus extend over a considerable range, but, inasmuch as the material when employed as a screen is intended for and in most instances will be employed for the purpose of barring insects, the range, at least in so far as the minimum number of meshes is concerned, will for that reason h e a practical limitation. Thus twelve meshes 0 elements per inch may well be a limit in one direction, while twenty elements per inch, due to physical difficulties in forming the elements 2|! may be a limit in the opposite direction.

In Fig. 1, which illustrates the material in approximately twice its actual size, the elements 2. are, by way of example, shown as running sixteen to the inch, that is, of an inch in width, while the dividing and supporting strips 22 are shown spaced one inch from center to center thereof and are of an inch in width. It is to be appreciated that these dimensions again are all arbitrary, though preferred dimensions, inasmuch as sixteen mesh screen constitutes by far the major portion of the screen customarily employed,

and any one or more the width of the supporting strips 22, the width of the elements 20, or the spacing of the supporting strips 22, may be varied. As shown in Fig. 1, the material is formed along each longitudinal edge with what is herein referred to as a selvage edge 23. By that is meant simply a marginal portion of the solid sheet varying in width from one-quarter to one-half an inch, which is left in its solid or imperforate state. Such a margin, particularly along the longitudinal edges of the material, provides excellent means for the securing of the material onto a frame as-by tacking or by clamping be-' tween opposed faces, and also forms a very excellent guiding portion for traveling in ways formed in a window casement or sash where the material is employed as an interior, roll-away screen. It will readily be appreciated that the material may, formed as it is of solid sheets and divided into columns one inch in width, be made in varying widths in multiples of an inch, and thus will readily be adapted for windows of any size. I

The material, being formed as it is from very thin sheets, is subject to injury, particularly deformation of the elements 20 by bending at right angles to the width, thus destroying the parallelism of the elements with resultant enlargement of the openings through which insects may more strengthen the elements 20, particularly against such bending, each of the elements is shaped to have other than a perfectly flat construction in transverse cross section so as to gain the inis formed is kept very thin and while the supporting strips 22 are very narrow to permit maximum light and sight through the material.

Where the material is formed from a metal sheet, the reinforcing filament 21 preferably is a wire. The wire filament is secured to the supcreased resistance to bending provided by such curved or angular cross section over aperfectly fiat construction. In the form of the invention shown in Figs. 1 to 5, the elements 20 are given a very slight bend 24 (see Fig. 3) parallel and closely adjacent to an edge thereof so as to result in what for convenience will be termed a lip 25. The remainder 26 of each element 20 in the form shown in Figs. 1 to 5 is substantially straight or fiat and this straight portion is disposed at about .84" with the plane of the sheet measured in the direction of rotation that the element is twisted.

It is immaterial whether the lip 25 is formed on the right hand edge or the left hand edge of the elements 26, as viewed in Fig. 3, so long as the lip projects in the general direction of the element and, particularly, in the same direction away from a perpendicular to the plane of the sheet passing through the center line of the element. Thus with the lips formed on the right edge of the elements, as viewedin Fig. 3, they project downwardly as viewed in that figure, whereas were they formed as they might be on the left edge of the elements 20, as viewed in Fig. 3, they should project upwardly. It will be apparent that when so formed the material, even when used as a screen, has no right or wrong side, or no outside or inside. and it is only necessary that care be exercised that the material be mounted with the elements sloping outwardly and downwardly. Thus in Fig. 3 the right hand side of the material would be considered the outside and, when so mounted, rain or moisture striking or collecting on the elements 20 would not be trapped but would be free to run off. Conversely the material of Fig. 3 might be inverted, in which event the lip edge would form the inside of the screen and, under those conditions, the elements 20 would still have a downward and outward slope and the lips would not serve to hold moisture or tend to direct it inwardly.

Preferably the material is also reinforced in what may be termed its longitudinal direction, that is, in the direction of the supporting strips 22. To that end all or selected ones of the supporting strips 22 are reinforced by a filament 21 extending longitudinally of the strips and secured thereto in a manner presently to be described. This filament should preferably have substantial tensile strength so as to aid the strips 22 in giving the necessary tensile strength to the material. Preferably also the filaments 21 should be resilient so as to tend to retain the material in its plane, but must be sufliciently flexible to permit rolling of the material. The filaments 21 may have any cross sectional shape desired but preferably a round filament approximately 9 of an inch in diameter is employed. While this diameter of filament may be departed from, it should preferably not be so large that the filament of the finished material projects outwardly beyond the edge of the elements 20 when the elements are in their final position. To have the reinforcing filament 21 extend outwardly beyond the edgepf the elements 22 has been found to interfere with the rolling of the material. It will be seen that by employing a reinforcing filament the necessary tensile strength of the material is obtained while the sheet from which the material porting strip 22 by welding either continuously or at closely spaced intervals, for example, every sixteenth of an inch or multiples of a sixteenth, so as to coincide with the center lines of the elements 22. Such welding at intervals is indicated by the broken line circles 28 in Fig. 2. Where the material is formed from plastic, the reinforcing filament 21 preferably is also of plastic. This filament is then by the application of heat or solvent, or both, readily secured to the supporting strip 22 either continuously or at spaced intervals, the same as the metal wire. In both the welding of the wire and the securing of the plastic filament, especially if they are secured continuously throughout their length, there is a tendency, as a result of the securing operation, to distort the filament somewhat from its round cross section to an oval cross section. This resultant oval cross section of the filaments 21 permits employment of filaments having a larger cross sectional area than a round filament without projecting beyond the edge of the twisted elements 20 and thus further increasing the tensile strength of the finished material. It is also pointed out that in the form of the invention shown in Figs. 1 to 5 the sheet 2| is so held during the die-cutting thereof to form the elements 20 that the supporting strips 22 remain substantially straight and fiat, as shown in Fig. 4. This enables and facilitates the securing of the reinforcing filament 21 thereto. While the filament 21 has been shown as applied to one side only of the supporting strips 22, it is to be appreciated that should still additional strength he desired a similar filament could likewise be applied to the other side of the supporting strips 22.

Figs. 6 to 8 disclose a slightly modified form of louvered sheet material. The material is of the same construction as that disclosed in Figs. 1 to 5 save for two respects. Like the material of Figs. 1 to 5, the material of Figs. 6 to 8 is formed from a solid sheet 30 divided by narrow strips 3| into a plurality of longitudinal columns composed of narrow and parallel elements 32 die-cut from the sheet 30 and twisted out of the plane of the sheet. The elements 32, like the elements 20, are curved or bent so as to strengthen the same against bending at right angles to their width. In this form of the invention each of the elements 32 is given a multiple curvature, this curvature taking the form of a bend 33 formed parallel with and quite closely adjacent to each edge of the elements 32 so as to form what will for convenience be termed lips 34 and 35. The portion 36 of each element intermediate the bends 33 is kept substantially straight and fiat and is disposed very nearly at right angles to the sheet 30, though preferably the angle thatthis portion 36 of each element forms with the plane of the sheet is short by at least a few degrees from a true right angle. It is essential that the lips 34 and 35 each continue in the general direction of the element 32 with respect to a perpendicular to the plane of the material passing through the center line of the element. In other words, the lips must extend in a direction away from such a perpendicular to the plane of the material through the center line of the element. When constructed in this manner, it will be apparent that the material,

even when used as a screen, has no inside or out-.

side, but either side may be turned outwardly so long as the material is mounted so that the elements 32 have a downward and outward slope.

In this form of the invention, the finished material, whether formed of metal or ofplastic, is given increased resiliency and to a limited extent is made resiliently yieldable in a longitudinal direction. To that end, the supporting strips 3| (see Figs. 6 and 8) are formed with undulations 31. While these undulations might be formed in a variety of ways, and while they may have varying amplitudes and also varying wave lengths, they are herein formed as an incident to the die-cutting of the sheet 30 to form the elements 32, such formation of the undulations being made possible by the manner in which the sheet 30 is held. Accordingly. the undulations have a wave length correlated with and determined by the width of the elements 32 havin a trough or depression 38 at the line of severance of the elements and a resulting high point or crest 33 at each center line of the elements. The result of such undulations in the supporting strips 3| is, of course, to give the material limited stretchability in a longitudinal direction and increased resiliency of the material, protecting the same against permanent injury resulting from the application of force to the face of the material when its edges, for example, are held in a frame or the like. Further, depending upon the amplitude of the undulations and any possible elongation of the material, the undulations may just compensate for the elongation maintaining the elements 32 spaced a distance equal to their width, or the undulations may foreshorten the material resulting in a spacing of the elements by a distance less than their width. Though not shown as being reinforced with filaments extending longitudinally of the supporting strips 3|, as is the material in the form of Figs. 1 to 5, it is nevertheless possible that such reinforcing filaments might be added and secured either to the high spots or crests of the undulations, or with the filaments also given undulations so as to coincide with the undulations of the strips 3| and then secured continuously, as described for the other form of the invention.

Figs. 9 to 13 disclose still a further slightly modified form of louvered sheet material. In this form the material is still formed from a solid sheet 40 divided by supporting strips 4| into a plurality of columns each composed of narrow and parallel elements 42. These elements may have a transverse cross section such as the elements 20 of Figs. 1 to 5 or the double curvature of the elements 32 of Figs. 6 to 8. The feature of this form of louvered material is that the elements 42 of adjacent columns are offset longitudinally with respect to each other. Preferably this offset is by one-half the width of an element thereby bringing the line of severance of the elements in one column in coincidence with the center line of the elements of the adjacent column. Among other advantages, such a construction has the advantage that any accidental extension of the severing cut as an incident to elements the twisting of the elements will not weaken the supportin strip to any material extent, because each severance cut terminates opposite the center of an element in the adjacent column and hence opposite a substantial amount of material. This is in contrast with a construction such as shown in Fig. 6, wherein the severance cuts in 8 adjacent columns are in registry with one another and thus very definitely leave at those points a supporting strip of only {I of an inch in width. Should one of the severance cuts extend into the strip as a result of twisting of the elements, the effectiveness of the strip would be.

greatly reduced and it is even conceivable that, should the severance cut on the opposite side of the strip also be extended, the two might meet and completely sever the supporting strip.

This offset or staggered relationship of the in adjacent columns materially strengthens the supporting strips .from the standpoint of tensile strength and renders less necessary any reinforcing filaments, though these may here again be applied as described in connection with the form of the invention shown in Figs. 1 to 5. Like the form of the invention of Figs. 6 to 8, however, the supporting strips 4| may also be given undulations so as to increase in well known manner the resiliency of the material when displaced out of the plane of the sheet, to stiffen the material somewhat and give thereto limited stretchability in a longitudinal direction. In this form of the inven-- tion, the undulations are complex rather than simple, as in Fig. 8, and can best be depicted and visualized as consisting of two waves side by side but displaced or half a wave length and, of course, partially merged by lateral overlapping, as must be the case where they are formed in one and the same strip 4|. As best seen from Figs. 10 to 13, inclusive, there is formed in the supporting strip 4| at the terminus of each severance cut a low point 43, depicted in Fig. 10 by small circles. Approximately at the center line of each element 42 is a high point 44 again depicted in Fig. 10 by a small circle. Appreciate that the depressions and

high points

43 and 44, respectively, are not sharply defined but are gradual and that the circles shown'in Fig. 10 are provided merely to locate the approximate bottom of the low points and the approximate top of the high points. With the gradual conformation of the strips 4| to provide both the low and the high points there will, of course, be a tendency of the low points to merge and, likewise, a tendency for the high points to merge, with the result that there is formed a zig-zag ridge or rib composed of the high points and their tendency to merge, and a corresponding zig-zag valley or trough composed of the low points, the crossing of the ridge and the valley resulting in a point which lies approximately in the original plane of the strip.

The amplitude of the undulations may vary and, depending upon the magnitude of such undulations, the spacing of the elements 42 may be efifected. When the undulations are kept small, they can be present without changing the spacing of the elements 42 by a compensating elongation of the strips 4| as an incident to the formation of the elements 42. It is believed possible, however, that the undulations may be given such amplitude as to effect a shortening of the strips 4|, in which event the elements 42 of the finished product will be spaced by a distance less than their width giving, in effect, a finer mesh material which will be more efifective to prevent the passage of insects therethrough and also more effective in prohibiting passage of direct light rays. The undulations, of course, give to the material a limited yieldability, particularly in a longitudinal direction, and also give to the material a certain sprlnginess and particularly a resiliency tending to restore the material to lying in a plane should it be bent out of the plane.

Figs. 14 and 15 disclose a form of louvered sheet material of the same general character as that heretofore described, namely, as composed of columns of parallel elements 45 formed from a solid piece of material with the columns separated by dividing and supporting strips 46 extending longitudinally of the material. In the forms of the louvered material heretofore disclosed, the angular relationship of the louvered elements with respect to the supporting strips has not been specifically defined, but the elements have been shown as disposed at right angles to the supporting strips. In Figs. 14 and 15, the elements 45 are shown as departing slightly from a strict right angular relationship to the supporting strips 46. The inclination of the elements 45 with respect to the strips 46 may be varied, but herein is shown as departing but a few degrees from a strict right angular relationship, more specifically, such inclination that one end of each element 45 is offset longitudinally with respect to its other end approximately the width of an element, that is, of an inch. T he purpose of this inclination of the elements is to permit making of the severing cuts I! as a shearing operation, that is, by a progressive cut longitudinally of the elements rather than as a simultaneous cut of the entire length which places an extra load upon the means forming the severing cuts. Whether the inclination of the elements in adjacent columns is in the same direct on as shown in Figs. 14 and 15, or is in opposite directions, is also immaterial. The elements 5 may be shaped as shown in Fig. 3 or as shown in Fig. 7, and the supporting strips 46 may be strai ht and reinforced or may be formed with undulations, as in Fig. 8 or Fig. 9. and the severing c ts may terminate directly opposite the severing cuts of the adjacent column. as in Figs. 1 and 6, or may terminate opposite the approximate midpoint of the elements of the adjacent column, as in Fig. 9.

When the material is made from a metal sheet, the surface of the louvered elements which is upwardly disposed, when the material is emplo ed particularly as a screen. is preferably treated so that it will at least diffuse the li ht ra s and preferably so that it will be light absorntive. In any event, the surface should not be hi hly polished so as to act as a light ray rei ectin surface. Where the metal is such as to deteriorate rapidly when exposed to the elements,

it is also preferable that some protective coating be given to the material. This might, of course, take the form ofpaint, but preferably takes the form of a galvanizing either deposited electrolytically or by the older and more conventional hot bath dipping process. Such galvanizing, especially the dipping process, not only serves to coat and thereby protect the material against the elements, but the galvanizing material tends to strengthen the supporting strips by building up to a greater than average depth at the points of the severing cuts. When the material is formed of a *plastic sheet, the sheet must, of course, be treated so as to prevent the passage of the direct light rays therethrough if the material is to fulfill its function of intercepting such direct light rays. This, of course, might be done bythe addition of some pigment so as to render the entire sheet more or less opaque, or it might 75 columns being composed only be done by applying an appropriate coating to the sheet. a

'Contributingb the advantage of this type of material over ccfiventional screen when the material is employed as screen, and similarly advantageous when employed in a variety of other ways, such as for conveyors, is the facility with which the material may be repaired when some one or more of the louvered elements become broken. It is believed readily understood that to repair a broken portion of this material it is only necessary that thebroken or damaged portion be cut out and that a section slightly larger than the cut-out portion be placed in position over the broken or damaged portion. It will be found that the elements of the repair section and the elements of the material being repaired will readily lie one beneath the other and that the supporting strips will also lie one against the other where they overlap and are free to do so. The margin formed by the overlap may be secured by spot welding, the supporting strips being welded to one another and the louvered elements being welded to one another.

It is believed apparent from the foregoing that I have perfected a louvered material of greatly improved construction, particularly improved in such respects that, though the sheet from which the material is formed may be extremely thin, yet the material as a whole and the individual louver elements are strengthened and reinforced in a variety of ways renderin the material more suitable for use as screen and additionally suitable for a great variety of other uses, such as conveyor belts for light-weight material, visors, glare shields, etc. In addition to strengthening and reinforcing the material and the elements thereof, I have given to the material increased resiliency and a possible limited yieldability. In addition the louvered ma-, terial, when made as herein disclosed, can, depending upon the magnitude of certain dimensions, have any elongation of the supporting strips as an incident to the formation of the material just compensated for so as to maintain the spacing of the elements by the width of the elements, or there may be an over-compensation resulting, in effect, in a finer mesh screen. 1 he material has various other advantages as brought out above. Q

I claim as my invention:

1. An insect screen formed from a solid, thin sheet having a plurality of parallel, continuous and equally spaced supporting strips dividing the sheet into columns and each of the columns being composed only of a plurality of uniform and parallel elements extending between said supporting strips and supported only by integral formation of the supporting strips and the elements at their ends, each of said elements being twisted about its longitudinal center line at an angle to the plane of the sheet and said supporting strips being formed with a row of undulations extending longitudinally thereof with the amplitude of the undulations at right angles to the plane of the sheet and with their period corresponding to the spacing of the elements to incorporate in the screen limited yieldability in the direction of the length of said supporting strips.

2. A louvered material formed from a solid, thin sheet having a plurality of parallel, continuous and equally spaced supporting strips dividing the sheet into columns and each of the of a plurality of uniform and parallel elements extending between said supporting strips and supported only by integral formation of the supporting ;strips and the elements at their ends, each of said elements being twisted about its longitudinal center line at an angle to the plane of the sheet and said supporting strips being formed with undulations whose amplitude is at right angles to the plane of the sheet and whose periodicity corresponds to the elements providing a high point and a low point for each element to incorporate in the material limited yieldabllity in the direction of the length of said supporting strips.

3. A louvered material formed from a solid, thin sheet having a plurality of parallel, continuous and equallyspaced supporting strips dividing the sheetinto columns and each of the columns being composed only of a plurality of uniform and parallel elements having a width substantially greater than their thickness and extending between said supporting strips andsupported only by integral formation of the supporting strips and the elements at the ends of the elements, each of said elements being twisted about its longitudinal center line at an angle to the plane of the sheet, and said supporting strips being foreshortenedv by displacement alternately in opposite directions out of the plane of the sheet, after severance of said elements along their side edges, to space said elements from one another a distance less than the width of said elements.

4. A louvered material formed from a solid, thin sheet having a plurality of parallel, continuous and equally spaced supporting strips dividing the sheet into columns and each of the columns being composed only of a plurality of uniform and parallel elements extending between said supporting strips and supported only by integral formation of the supporting strips and the elements at their ends, each of said elements being twisted about its longitudinal center line at an angle to the plane of the sheet and the elements of alternate columns being offset longitudinally of the supporting strips by less than the width of an element, and undulations formed in said supporting strips to add resiliency thereto.

5. A louvered material formed from a solid,

thin sheet havingya plurality of parallel, continuous and equally spaced supporting strips dividing the sheet into columns and each of the columns being composed only of a plurality of uniform and parallel elements extending between said supporting strips and supported only by integral formation of the supporting strips and the elements at their ends, each of said elements being twisted about its longitudinal center line at an angle to the plane of the sheet and the elements of alternate columns being offset longi- 12 tudinally of the material by one-half the width of an element, each of said supporting strips being formed with a double series of undulations.

6. A screen-like material formed from a solid, thin sheet having a plurality of parallel, continuous and equally spaced supporting strips dividing the sheet into columns and each of the columns being composed only of a plurality of uniform and parallel elements extending between said supporting strips and supported only by integral formation of the supporting strips and the elements at the ends of the elements, each of said elements being twisted about its longi tudinal center line at an angle to the plane of the sheet, and each element, in the direction of the length thereof, forming with the supporting strips to which it is attached an angle deviating by a few degrees from a right angle.

7. An insect screen formed from a solid, thin sheet having a plurality of parallel, continuous and equally spaced supporting strips dividing the sheet into columns and each of the columns being composed only of a plurality of uniform and parallel elements extending between said supporting strips and supported only by integral formation of the supporting strips and the elements at the ends of the elements, each of said elements being twisted about its longitudinal center line at an angle to the plane of the sheet and composed of a major central portion disposed at a large angle to the plane of the sheet and a minor flange at each edge, each flange forming a small angle with the major portion and extending in the same general direction away from the major portion as that half of the major portion carrying the flange extends from a perpendicular to the sheet passing through the center line of the element.

- HAROLD WARP.

assurances crran The following references are of record in the file of this patent: