US2142996A - Metallic roofing shingle - Google Patents

Description

Jan. 10, 1939. E. Bussi-:Y:

METALLIC ROOFING SHINGLE Filed July l5, 1955 3 Sheets-Sheet l INVENTOR 51e/V557 5f/555V.

ATTORN EYS Jan. 10, 1939. E. BUssEY METALLIC ROOFVUG SHINGLE Filed July l5, 1935 3 Sheets-Sheet 2 FT'GJI.

INVENTOR ERNEST Bassa-Y ATTORNEYS Jan. 10, 1939. E. BUSSEY METALLIC ROOFlNG SHINGLE Filed July l5, 1935 3 Sheets-Sheet 5 FIG. 22

INVENTOR ERNEST BusL-TY ATTORNEYS Z V/z'@ Z6 23657 M 26 Z8 Z Z8 f quickly laid and thoroughly leak-proof roof. v each butt portion carries its own lock lug it fol- `15 `construction and manner of laying shingles as members to a narrow zone at or beyond the tip 15 25 face required per. square .of rooiing to be covered: tively inverted outwardly extended ears though 25 l 30v j oint area so that it will resist. wind pressure shingles, havingtapered butts and side nailing 30 '35 My invention further contemplates suplacing bers stopping short ofthe adjacent nail. The ar- 35 45 held down and provide that close surface-com. the nailed corner or ear of a subiacent shingle, 45

Patented Jan. 1o, 1939 2,142,996

UNITED STATES PATENT OFFICE METAmc noornvol snnvGLE Ernest Bussey, Birmingham, Ala.

Application July 15, 1935, Serial No. 31,373

` n-omims. (c1. ros-17) My invention relates to an improvement in on either side of the center line of the diagonal shingle roofs and more particularly to a novel cut which separates the shingle butts from the design of metallic or rigid shingles anda Vnew adjacent shingle ears. and improved method of cutting, laying and 'Ihus I can provide unitary metallic shingles '5 interlocking same solas to provide an economic, which are symmetrical and reversible and since 5 In Letters Patent No. 2,008,575 I have shown lows that when a shingle isA cut to nt a rake or g and described the. general design of the shingle valley both portions thereof can be utilized hecontemplated in my present invention, but that cause the part cutaway to nish out one course 10 application was more particularly concerned with will iit into a course above. v l0 flexible composition shingles and a novel manner By conning the lock elements to this area the of laying same. side lap relationship of the shingles throughout In my present invention I am carrying into the all, or.: practically the whole, of their exposed lap rigid or metallic shingle art the principles of joints is preserved and by conning the lock defined and claimed in said patent, with such of the exposed butt the edges of such butt can be changes `as are necessary to obtain the benets kept sulilciently removed from the nails in the of my improved type of roof from this different underlying foundation to safe guard the latter Shingle stock. from water penetration. By cutting out all of 20 One object of lmy invention is to provide a the stock in such narrow zone except sulclent to 20 metal Shingle that can be laid over new work or form the lock element itself, I produce a shingle as a recover shingle over old roofs, andzwhich having my preferred conguration in that, while is preferably of large size and adapted to be laid all of its opposite sides are parallel and equal in with a small side lap so the ratio ofA shingle surlength, the upper and lower edges of its relawill be kept very low. A equal in length to each other are unequal in A Mypresent'invention' contemplates an improved length to opposed upper and lower butt ends of method of reinforcing and stiiening the 'central the shingle. Another important feature of my portion of the shingle lying 'within its marginal invention relates to a roof composed of metallic S errerted against its exposed butt tip and yet be corners, which'are anchored to each other and fully flexible transversely Vso that its side lap joint the decking by means of hold down lock members edge portions are free to lie in close surface coand nails respectively arranged in the vertical tact with the underlying roofl elements. center line of the shingles with the lock memthese 'reinforcements that they are symmetrically rangement is only permissible with rigid stock disposed in the shingle and lie vertical so Ythat from which a strong lock lip can be formed and the shingle may be cut and reversed with all of it hasthe very'important advantage of keeping the economic advantages pointed out in my applithe nailsY removed as far as possible from the butt 40- cation aforesaid. Y edges. l 40 My 'invention further comprises` a 'varietysoiA Since each metal shinglein such a roof will effective arrangements by which' the exposed butt haveanchorfnails applied ,only in its side corners tip of the shingle 'can be so interlocked with one or. ears after the lock -member at or near the ci its foundation elements that it will be firmly -oenter'of itsvbutt tip'has Vbeen engaged under tact throughout the side lap-joints so necessary 'to it follows` that, in the manner well understood in inSlle the IOO against-leakage#- 2 Y t the'roong art, its nails may be driven so as to My invention is particularly concerned with stretch the side edges of its butt diagonally upproviding said butt tip lock elements without such wardly away from the lock member thereby to :.0 a waste of stock material as will increase theY draw' such vedges into close, surface contact 50 cest of roong per square of roof to be covered throughout the lap joint with the subjacent and to this end it is proposed to out the shingles shingle edges and to hold these edges firmly from stock just as described in my companion together against any tendency to separate and application, except that the lock elementlis formed open suchjoints. mithin a zone lying about one quarter of an inch My invention further comp es the pre-treat- "55 ment of a metallic starting strip so that it will serve to line the bottom row of shingles and to interlock therewith so as properly to space them, matching nail holes preferably being punched in the strip and in the shingle ears so as to enforce the correct alignment of the starting row of shingles. f

My invention also contemplates forming on the shingle ears the match marks such as are called for in my patent, and punching the nail holes near the middle of the diagonal edge of the ears.

My invention further contemplates the novel manner of nishing along the rake of the roof, and also along the eave.

My invention further comprises the novel details of construction and arrangements of parts which are illustrated in the accompanying drawings, in which:-

Fig. 1 is a plan View of a sheet metal stock strip showing one of the shingles blanked out and provided with a lock lug on its butt ends.

Fig. 2 is a plan View of the cut out shingle standing in the position in which it is laid but Without its lock lugs being bent.

Fig. 3 is a vertical sectional line on the line III-III of Fig. 2 showing the shingle with its lock lugs bent to operating position.

Fig. 4 illustrates a modification of my invention in which-each lock lug, shown unbent, is formed with a complemental socket in the carrying element adapted to nest over the underlying socket element in which such Vlugs is adapted to be received.

Fig. 5 is a sectional view taken on the line V--V of Fig. 4.

Fig. 6 is a view corresponding to Fig. 4 showing the lock lug bent under into operating position.

Fig. 7 is a sectional View taken on the line VII-VII of Fig. 6.

Fig. 8 is an end elevation of Fig. 6.

Fig. 9 is a View in half size showing an interlocked butt joint for shingles according to the showing in Figs. 4 to 8.

Fig. 10 is a View of a portion of a roof showing the metal starting strip along the eave and a diagonal cut for valley or hip with rst and second course shingles laid up and interlocked in operating position with the centers of the shingles shown with stiening ribs.

Fig. 11 is an enlarged cross sectional view taken on the line XI-XI of Fig. 10.

Fig. 12 is a view corresponding to Fig. 9 show ing a modification of the shingle ear carrying in its longitudinal edge a lock lug adapted to engage a similar lug on the overlying shingle butt.

Fig. 13 is a section taken on the line XIII-XIII of Fig. 12.

Fig. 14 illustrates the manner of making the diagonal cuts in the stock to form the lock elements on the butts and ears of adjacent blanks according to Fig. 12.

Fig. 15 is a view corresponding to Fig. 12 of a modified type of notchout and lug interlock for the shingle. l

Fig. 16 is a sectional view taken on the line XVI-XVI of Fig.15.

Fig. 17 is a View corresponding to Fig. 14 showing the lines for cutting out the shingle blanks shown in Fig. l5.

Fig. 18 is a view corresponding to Figs. 12 and 15 of a further modification of my notch and lug interlock.

Fig. 19 is a sectional view taken on the line XIX-XIX of Fig. 18; and

Fig. 20 is a view corresponding to Figs, 14 and 17 for cutting out the shingle blanks shown in Fig. 18.

Fig. 21 is a detail sectional view showing the manner of iinishing the rake.

Fig. 22 is a View similar to Fig. 10 showing the reinforced shingles without lock lugs.

Fig. 23 is a cross section on the XXIII- XXIII of Fig. 22.

Fig. 24 is a fragmental View illustrating the shingle blanks being cut with the lug that is shown on the butt in Fig. 1, carried by the shingle ear and adapted to be bent up over, instead of under the butt.

Fig. 25 is a View illustrating a further method of cutting the shingle blanks to provide the complemental butt and ear edges with lock lips.

Fig. 26 shows a modication of Fig. 25.

Fig. 27 is an enlarged View showing a shingle butt interlocked by the lips shown in Fig. 26.-

Similar reference numerals refer tof similar parts throughout the drawings.

According to the embodiment of my invention illustrated in Figs. 1 and 3, I show my improved type of shingle cut from a metallic strip 2i, but it will be noted that it may be cut from any suit able shingle stock. The individual shingle blanks are cut from the strip by similar spaced zig-zag lines which form continuous parallel transverse cuts that are enlarged at their parallel inclined ends to form juxtaposed side edges 22 and spaced diagonal edges 23 and 24, these latter edges being spaced, in the full sized shingle, approximately one-half inch so as to leave space in this cut out zone for the formation of a semi-circular lock lug 25 which is carried by the truncated tips of the butt portions 26 of the shingle body 2l. The side edges 22 form equal opposed parallel inclined side edges of the shingle when in its operating position shown in Fig. 2 and the other side edges of the stock form the equal interposed parallel inclined edges 22a of the shingles, these edges 22, 22a dening a body substantially square except for ears 28, 28a which are complemental, similar and reversely disposed and made up of the stock cut away to truncate the butts 26. This manner of cutting the shingle corresponds substantially to that described in my patent aforesaid with the exception that in that application there was no blanking out of stock between the edges 23 and 24 in the diagonal ends of the cross cuts because it was unnecessary to provide the locking lugs 25 where cement was used to hold down the butt tips.

In order to form the lugs 25 within the area available for the cutting out of the shingle blank without disturbing its side lap, I drop back approximately a quarter of an inch from the center line of the diagonal cuts, as shown in my said patent, this portion cut away from ear and butt leaving a half inch of stock for the formation of the lock lug 25 without causing wastage in shingle stock that represents a l`oss in effective roof coverage because the roof can be laid with these cut away shingles without increasing the number of shingles required per square of roof. In cutting out the shingles the cutting tool or shear will carry with it elements which will apply to each ear at the center of its diagonal edge an alignline ing marker 29, it being noted that these markersl align with the shingle edge lying across the eax. At the same time and in the vertical center line of each ear near'its diagonal edge is punched a nail hole 30. In the same or succeeding opera tions the lugs 25 are bent under as shown in Fig. 3 so as to receive under them in the bight thus Cil formed one thickness of metal stock. In Fig. 2 the lugs are shown unbent, but in Fig. 3 they are bent.

Shingles, as thus made up, are laid exactly like the shingles described in my patent aforesaid, with the exception that in lieu of the use of cement I provide the lug 25 or some equivalent means to hold down the exposed butt by engagement with some part of the lower edge of the ear which forms half of its underlying foundation.

Assuming these shingles to be of 28 gauge stock, it will be apparent that the shingle butt will be only slightly raised by the lug under its center and that this rise will disappear toward the inclined edges 22 and 22a of the butt so as not to interfere with a flat surface contact throughout the side lap joints with underlying roof elements.

Fig 10, While illustrating a modification of my invention, may be referred to for the purpose of showing the manner in which the ears 28 and 28a of adjacent shingles in a row abut and are matched by their markers 29 to form the foundations for the overlying shingle buttsA which are to be 'interlocked therewith by hooking their lugs 25 under the low edge of the adjacent ears 28a.

In Figs. 4 to 11 I show a modification of my invention wherein the butt stock 26 in the cutting operation is pressed up opposite the lock lug 25 approximately the thickness of the stock to form a raised pocket 3| level with the locklug 25, which lug, as shown in Fig. 7, is bent under the pocket and spaced therefrom the thickness of the metal stock. The top of the pocket and the lock lug 25 form a circular surface with its center in the base line of the cut awayA butt and at the center thereof. Like semi-circular pockets 3| are pressed up on the horizontal edge of each ear 28 and 28a and adapted to nestin the matching pocket of any lug engaged therein as shown in Figs. 9 and 11.

Fig. 11 shows the raised surface 3| forming the pockets on the upper tip 26 of the underlying shingle 21 and on the lower tip 2S of the overlying shingle 2T nested into similar raised pocket elements 3| provided in the abutting ears 28 and 28a onthe interposed shingles on each side of the particular joint being shown.

It will be noted that the lock lug 25 of the exposed butt of the shingle is engaged in the pocket of the ear 28a and is thereby held down firmly. Nails are shown driven into the decking 33, these nails being driven through the previously punched holes 3D in the ears 28 and 28a. The nails are also driven through the underlying shingle just below its pocket 3| at its upper butt tip and at the same time the nested pockets 3| on the ear 28 and the upper shingle tip are struck and flattened down as shown in Fig. 11.

The lock lugs of a shingle lie in its vertical center line or diagonal, which is in line with the anchor nails for the ears forming the foundation for its exposed butt tips, which arrangement is possible because the lug is designed to stop short I side edges of the shingle butt to a flush surfacel contact with the underlying lap surface that will prevent water being carried across the joint by capillary action and gaining access to nails or decking.

It may be desirable to stiifen the shingle stock. particularly where it is formed of light gauge metal, and it is important that this be done by the provision of stiiening ribs which will lie vertically in the shingles as laid, which will be confined to its exposed single ply roofing surface 1ying within the lap joints of itscomponent shingles, and which will preferably be of symmetrical arrangement so that the shingles, when inverted or cut, will match. As shown, I provide three ribs, a center rib 34 and shorter parallel side ribs 35, the ends of all ribs stopping short of the marginal lap joints of the laid shingles and all lying vertical will offer no resistance to the flexing of the shingle about any vertical axis to secure the close watertight side lap joints. The ribs will however resist any flexing of the shingle about its .horizontal axis and will stiffen its exposed butt to first course of shingles.'

The starting strip is preferably laid with a half inch overhang beyond the decking 33 forming the eave, see Fig. l0, and on the'strip spaced according to the size of the shingles I form raised pockets 3|, corresponding to those already described and therefore adapted to receive the lock lug 25 on the butts of the first course of shingles and to I accurately space them. At the Sametime while the starting strip has these pockets pressed up therein I punch an attaching nail hole 31 immediately above each pocket 3| and I'also punch in this strip 2| holes 38 Which are appropriately' spaced on centers to match with the holes 30 in the ears of the first course shingles, it being noted particularly by the dotted line showing of these nail holes in Fig. 9 that the nails for the ears 28, 28a in each foundation will fall in vertical alignment.

Also in order to maintain uniformity in the appearance of the roof the showings on the starter strip between the first course shingles are provided with portions of reinforcing rib elements 34 and 35 which will match up with the shingle exposures on the roof. l

In Fig.` 10 the diagonal line 40 represents the manner in which the shingles .are cut to valley or hip lines but the special advantages of my shingle for this purpose being the same as that described for the shingle of my patent aforesaid needs no further description herein.

In Fig. 2l I show the manner of forming the rakes of the roof, the decking 33 being shown with the side board 4| attached thereto and a four inch strip of 20 gauge metal 42 nailed to the necking -along the rake so as to slightly overhang the side board. The starting strip 36 is carriedout to the edge of the strip 42 and the edge of the shingels 2T are cut so that they overhang about one-half of an inch beyond the strip 42 and after they have been nailed their free edges are bent over the edge of the starting strip and the strip 42 and engaged under the latter to lock the shingle edges in position.

Having first laid the rake strips 42 and then rpplied the starting strip along the cave I am ready for the laying of the shingles and this proceeds, the lock lugs 25 of the rst course being rapidly and with ease engaged in the receiving pockets 3| along the base of the starting strip, and thus aligned, correct angular position being quickly and exactly secured by matching the upper edge of each shingle ear 38 with the top edge of the strip and aligning the hole 30 with the corresponding startng strip hole 38, whereupon the shingles are nailed through the matched holes 38 sind 38 into the decking and the first course is quickly and accurately set in proper position for the correct laying of the succeeding courses.

The laying of the roof proceeds by engaging the lock lugs 25 of the second course shingle butts in the pockets 3| of the ears 28a of the first course shingles, after which the lower edge of each ear 28 is matched with the upper edge of an ear 28a, that abutsit diagonally across a foundation, by

bringing their markers 29 into alignment and then nails are applied through the holes 30 in each pair of abutting ears and driven through the upper butt end 26 of the underlying lower course shingle to secure them in posit-ion and stretch or pull up the side edges of the exposedbutt so as to insure tight lap joints and rigidly held exposures. The standard shingle will thus be anchored, except at corners by lock lugs and nails lying in vertical diagonal planes through it. At the same time that the right ear 28a is brought into alignment by its match marks 29, the left ear 28 is also aligned not only by the edge matching with the upper butt edge underlying it but also by the nesting of its pocket element 3| with the pocket on the said underlying shingle butt.

Thus, a check is provided for alignment and the roof can be rapidly and accurately laid by unskilled labor with the marginal edges of its shingle exposures lying in close surface contact throughout their respective lap joints. As stated before, when each ear 28 is nailed down the pocket 3| thereon is flattened by a hammer blow because it does not match with any corresponding element on the overlying shingle and would thus serve only to raise the latter. The concealed lock lug on the top butt portion may be bent under as shown in Fig. 3 or left flat as shown in Fig. 2.

In laying the shingles they can be inverted and either portion 26 may be its lower or exposed butt. This has many practical advantages both in respect of speed in laying and salvaging of stock. In Figs. 12 to 14 I show the shingles cut without wastage between the edges 24 and 23, the corresponding edges being separated here by a shear cut 45 as is shown in Fig. 14. This gives an edge 23a iess in length than 23 but equal in length with the edge 24a. I form at the center of this cut 45 opposed side cuts which define lugs 46 and i60. that lie within the areas of the butt and ear respectively, and when the shingles are laid these tongues will overlap and their free ends will match and can be bent up under or over to interlock the butt of the shingle to the underlying ear. In Fig. 13 I show the lugs 46 and 46a bent up and interlocked.

In Figs. 15, 16 and 17 I show the lug 46 cut out at 41 to provide a notch, the inner edge of which is in a position to be engaged in the bight of the bent lug 46a as shown in Figs. 15 and 16.

In Figs. 18, 19 and 20 I show the reverse of the lock arrangement Fig. 15, here the tongue 46 being left on the shingle butt and the notch out 48 being formed in the ear. In this arrangementA when the shingles are laid the bent ear 46 is engaged under the transverse edge of the notch 48.

In Fig. 24 I show the same manner of cutting the lock lug as in Fig. 1 except that here the lug 25a is attached to the edge of the ear 28a rather than to the edge of the adjacent shingle butt 26 and is bent up instead of down.

In the embodiment of my invention shown in Figs. 22 and 23, the shingle 50 is out from the stock as described in my patent aforesaid without waste and without any lock lug on its butts 26. The stiiening ribs 34 and 35 are formed in the metal of the shingle body parallel with its vertical axis and symmetrically arranged in that central portion of the shingle body lying within its marginal lap joint area so as to stiffen the shingle against any tendency to bend about a transverse axis away from the underlying foundation, while leaving it free to bend about a vertical axis to insure full surface contact throughout its marginal lap joints with the shingles lying under or over it. These shingles are laid with a starter strip 5| having nail holes 31 and 38 punched therein in proper position to match with the holes 3U in the ears 28 and 28a. The ve shingles cut by the section line in Fig. 22 are distinguished by the numerals 50a, 58h, 50c, 50d and 58e, and it will be apparent that each pair of abutting ears 28 and 28a provides a flat foundation on which the lower butts of the shingles in the next course will rest.

The corner nails that hold a shingle lie in a transverse inclined line below the transverse middle plane of the shingle and this line intersects the lower ends of the ribs 34 and 35 so as to hold the exposed shingle butt stretched firmly down iiat on the underlying shingle edges with the ribs stiiiening it against bending up.

In Fig. 25 I show the lock elements formed as ears 5|, 52 by slits starting in a line normal to the center line of the diagonal cut 53 and equidistant therefromv and meeting in said out with the inclination of said slits reversed in the connected cuts 53. The shingles are laid with the ears reversely disposed between the butt and underlying ear 28a. whereby the ears may be slightly bent reversely so as more readily vto interlock when the shingle butt is shifted sidewise into correct position. 4

In Fig. 26 I show the lock ears 54 and 55 formed by angle cuts 53, each starting normal to the cut 53 and terminating in a fillet 51 at a line normal to the center of the cut 53. By bending these ears reversely and interlocking them by a. lateral movement of the shingle butt I get the joint shown in Fig. 27 which is very effective both to interlock the butts to the ears 28a and also to center the butts with reference to their foundations.

While I have shown my invention in several forms, it will be obvious to thoseskilled in the art that it is not so limited, but is susceptible of *various other changes and modifications, withf out departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:- A

1. A roof comprising metallic shingles, each having a tapered truncated butt and side .nailing corners, which lcorners on adjacent shingles in a. row abut to form foundations for overlying shingle butts, nails securing said corners and applied in the central zone of such foundations, the tip edge of a shingle butt in one course being matched with the lower edge of its respective subjacent foundation, and a lock element cut from one of said matched edges and adapted to interlock with the other matched edge to hold down the overlying shingle butt, said lock element stopping short of the foundation zone carrying the nails.

2. A roof according to claim 1, in which the shingles'are laid with marginal lap joints and the overlapping elements throughout each joint are drawn into close surface contact with the overlapped joint elements by a tension between the lock elements and the corner nails of the shingles.

3. A roof according to claim 1, in which the side nailing corners of adjacent shingles in a course abut diagonally to provide a foundation with parallel top and bottom edges, and interlocking elements formed from portions lying within said matched edges to hold down the shingle butt.

4. A roof according to claim 1, in which the corners of adjacent shingles 4in a course abut diagonally to provide a foundation with parallel top and bottom edges, and the lock element being bent from the middle portion of one matched edge into position to interlock with the other edge.

5. A metal roong shingle generally square except at its corners, its upper and lower corners being truncated and stock substantially equiva-v ythe ear with which it interlocks at the point of engagement therewith.

6. A .metal roong shingle having a truncated butt andside nailing corners, one comprising an ear substantially equal to the stock removed in .truncating the exposed shingle butt and having aYL base edge parallel with the buttl tip edge with which it is adapted to be matched, in laying, and a lock means for a shingle butt formed near the center of one of said matching edges and stopping short of the distance between the matched ear edge and the position for its retaining nail.

7. A metallic shingle having a generally square body with opposed reversible truncated upper and lower butts and with side nailing ears projecting from the shingle which are adapted in adjacent shingles of a row to abut and provide a foundation shaped to form a horizontal matching edge for the butt of an overlying shingle, and corresponding aligning lock tabs projecting symmetrically from the center of both truncated butt edges, the lowermost of which is adapted tohook under said horizontal matching edge.

8. A metallic shingle having a generally square body with opposed reversible truncated upper and -lower butts and side `nailing corners which are corresponding aligning lock tabs projecting sym- 1 metrically from the center of both truncated butt edges, the opposed edges of theshingle body being equal and parallel and the butt matching corner edges being parallel with, but shorter than, the butt edges with which they are intended to match. 9. A metallic roof comprising reversible shingles having a generally square body with opposed like'truncated upper and lower butts and offset side nailing corners, which corners are adaptedv to abut with corners of adjacent shingles in. a course to provide a flat foundation, continuous with and lying in the plane of the marginal side lap joint edges of the shingle and having parallel upper and lower edges adaptedto match with the underlying and overlying truncated butt edges of shingles in the adjoining courses, and a lock tab projecting from each matching butt edge'and oifset substantially from the side joint edges,

which tab on the lower butts is adapted to be bent and interlock the matched edges and to lie between the projected side lap joint areas and below the nailing zone of its respective corner.

10. A metal roofing shingle having a truncated butt and side nailing corners, one comprising an ear substantially equal to the stock removed in truncating the shingle butt and having a base edge parallel with the butt tip edge with which it is adapted to be matched, in laying, and a lock means for a shingle butt formed by a short n arrow lug disposed in the center of and substantially spaced from the ends of both of said matching edges, said lug being in length less than the verticalwidth on the center line normal to the horizontal edge of the ear with which it is adapted to engage in laying.

11. A unitary shingle of flexible stock and approximately rectangular outline having symmetrical truncated opposed butt ends adapted for interchangeable exposure, side nailing corners adapted toreceive anchoring nails for the shingie in position to be covered by the exposed butt of an overlying shingle, and duplicate hold down elements similarly placed on the truncated end of said butts the lowermost of which elements is l bendable into position to interlock the exposed butt with an underlying nailing corner.

ERNEST BUSSEY.

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