US2272078A - Panel - Google Patents

Description

P. ZALKIND Fe. 3, m2.

PANEL Original Filed Oct. 19, 1935 5 Sheets-Sheet l PAY/ p Zkumva M *W P. zALKmD Feb. 3 142.

PANEL Original Filed Oct. 19, 1935 3 Sheets-Sheet 2 Feb. 3, 1942. P. ZALKEND 9 9 PANEL Original Filed Oct. 19, 1955 s. Sheets-:Sheet :s

Patented Feb. 3, 1942 2,272,o78 V I PANEL, Philip Zalkind, New mk, N. Y. Original application october 19, 1935,"Serial No. a

45,708. Divided'aml this application October" 11,1938, SerialNo.234,405.

H n I '5 Claims. (Cl;189:-53 My invention relates to panels, and morepar ticularly relates to plug shaped, folding panels" made of sheet and/or fibrous material such as corrugated board, container board-fiberboard,

sheet metal and the like, and is a division of my co-pending application Serial No. 45,708 filed October 19, 1935. g

My panel comprises a substantially fiat member provided with an outstanding hollow, plug shaped reinforcing member secured tothe periphery of the panel. In the preferred 'ernbodi- 1 ment of my invention, I fold the panel with its peripheral reinforcing member from a single blank of suitably shaped and scored'sheet ma terial.

The hollow outstanding extension which forms the plug, not only greatly increases the strength and rigidity of the panel but also provides a resilient bead forming a part of the panel and a complete boundary for the panel.

I have found that'a panel constructed accord- 1 ing to my invention may be used for many purposes. In my copending application, Serial No. 739,962 filed August 15, 1934, I have shown my reinforced panel in several modifications applied as a door for a collapsible cabinet, and the present application is a continuation in part of the above mentioned copending application. Other uses to which my reinforcedpanel is applicable, areas a top for a collapsible table; as

a top for an inexpensive desk; as a cover for a collapsible clothes hamper; as a tight sealing end for a container, such. as a dust proof collapsible transfer file or as an endseal for an ice-cream shipping containers I recite the above usesas examples only, as my panel in itsseveral modifications may be used for many other purposes.

In my several copending applications filed coincidently with my parent application and copending with this application and entitled:

Drawer, Serial No. 45,711; Three sided casing, Serial No. 45,714; Predetermined bend line, Se rial No. 45,710, and Container fastening means, Serial No. 46,316, all filed October'19; 1935, Ihave shown several forms of filing cases and drawer to which the panels of the present application 1 may be adapted.

The preferred size and, shape of my plug reinforced panel will vary with the particular ,con-

struction in which it is employed. Thus when it is used in large horizontal panels such'as are required for table and desk tops, the reinforcementsv will be larger thanwhen it is used as an end for a dust proof transfer file. Also when used for instance as a table top, the outstanding my invention. l I n Figure 2 is a perspective View, partly broken away, showing the'panel from blank of Figure 1.

reinforcements serve principally for their structural strength and rigidity, acting as box girders to carry the load of the 'panel back to the table supports; while when used as aniend for an ice- I cream;con tainer, a'dust proof cabinetv do'onetc 'theresilient properties'of the reinforcement act to produce a tight'seal between the panel and the opening whichthe panel is designed to close.

Accordingly, certain objects of my invention are to provide a novel-construction: of a panel sheet'material, such as. an impervious. substance which maybe folded for shipment; which has structural "strength and rigidityywhichmay be used as a closure member for an opening to effectivelyseal the opening; which has ruggedness ;to' withstand wear and tear; which has a pleas-- ing appearance; and which is inexpensive to construct and transport.

There are numerous other objectsof my invention which will become evident in the course of the detailed description which follows incon-,

nection withthe'drawings in'which:

Figure 1 is a developed bla' k of one form of Figure '3 is a developed blank of a modified form of my panel. l

' Figure 4 is a perspective view, showing the panel from the blank of Figure 3.

Figure 5 is a developed blank of a" corner memi her for use with the panel of Figure 4.

Figure 6 is an enlarged cross section of the p1ane 6 -6 of Figure 4.

Figure 7 is a develop'edblank of a further modified form of panel".

Figure 8 is a perspective view, partly broken away, of a panel formed from the blank of Figure'7.

Figure 9 is an enlarged cross section on the plane .-9- 9 of Figure8 looking in the direction of I the arrow. n f

, Figure 10 is an enlarged cross section on the plane Ill-40 of Figure filooking in the direction 'Jofthearrow. 1, j Figure 11 is a developedblank of another modification.

Figure. 12 is a perspective view, partly broken 7 away, showing the blank of Figure 11 witha base member similar to Figure 14.

Figure 13 is one form of base memberfor use in connection with the blank of Figure 11.2

; Figure 14 is another form of base member for use in connection withthe blank of Figure 11. Figure 15 is an enlarged'cross section on line I5-I5 of Figure 12 showing the blank of Figure 11 combined with the base of Figure 14.

Figure 16 is an enlarged cross section showing the blank of Figure 11 combined with the base of Figure 13.

Figure 17 is a developed blank for a further modified panel.

Figure 18 is a perspective view, partly broken away, showing the panel from the blank of Figure 17 Figure 19 is an enlarged cross section on the plane I 9I9 of Figure 18 looking in the direction of the arrow.

Figure 20 is a developed blank of a further modified panel.

Figure 21 is a perspective view of the panel shown in blank in Figure 20.

Figure 22 is an enlarged cross section on line 22 Figure 21.

Figure 23 is a developed blank of a further modified panel.

Figure 24 is a cross section in perspective showing panel formed from blank in Figure 23.

Figure 25 is a perspective view of a modified panel shown in blank in Figure 26.

Figure 26 is a developed blank of Figure 25.

In Figures 1 and 2, I have shown a panel for use as a door for a cabinet such as I have shown in my copending application Serial No. 739,962. As shown in Figures 1 and 2, the blank I has parallel scored lines as 2a, 2b, 2c, and 2d on one side; 3a, 3b, 3c, and 3d on the corresponding opposite sides; 4a, 4b, 4c, and lid on the top; and 5a, 5b, 5c, and 5d at the bottom. Reinforcements of square cross section are formed, from these scored portions by turning the sections on their score lines.

The blank I is divided by the scores 2a, 3a, 4a, and 5a into the main panel 6, and the two side flaps I and 8, and the two end flaps 9 and I0.

Each of these flaps folds over to form a hollow, resilient, rectangular reinforcing member along one of the four edges of the main panel 6. Thus the reinforced edge "I shown in Figure 2 is formed from the flap 1 of Figure 1 by bending the flap 1 along the score lines 2a, 2b, 2c, and 2d. After bending the reinforcements into position as shown in Figure 2 they may be secured in place by any suitable means, as for instance proper adhesive means. Illa respectively of the flaps I, 8, 9, and I0 may be pregummed, so that by moistening these flap portions they will adhere to the back of panel 6 when they are folded into position.

A series of slots IIa, IIb, and Ho provide means for attaching a hinge portion to the door member, with the fastening means for the hinge within the side reinforcing member. The opening II d provides means for mounting a handle within the other side reinforcement with the handle protruding through the opening IId.

While as shown the reinforcing members are shown as being rectangular in cross section, they may be slightly sloped inwardly on their outer portion, so that the inside of the door is somewhat smaller than the outside of the door, producing a wedge construction. If then the inside of the door is slightly narrower and shorter, and the outside of the door is slightly wider and taller than the door opening, when the door is closed, it is held closed by the wedge construction, and the opening will be tightly sealed with the resilient reinforcement closely conforming to the door opening.

In Figures 3, 4 and 6, I have shown a modified Thus the portions 1a, 8a, 9a, and

form of my invention. This form is also applicable as a door. The blank for the door is shown in Figure 3. The distinction between this blank and the blank described in connection with Figure 1 is that the material is cut away as at lb, Ic, Id and le; 81), 8c, 8d, and 8e; 9b, 9c, 9d, and 9e; and I02), I00, Id, and IOe so that when the flaps are folded along the score lines, the reinforcing members will meet each other at the corners in miter joints, while the blank of Figure 1 provides square butt joints. Slots Ila, IIb and I I0 of reinforcing flap I register with hinge slots Ila, I Ib and I I0 respectively of area B when the reinforcement is folded up and likewise cut-out IId of flap 8 registers with handle cut-out of Nd of member 6.

As was described in connection with the blank of Figure 1, the hollow reinforcing members may be secured in place by means of adhesive applied to the outer portions la, 8a, 9a, and Illa respectively of the flaps I, 8, 9, and III; or other securing means such as rivets may be used. Furthermore, the outer portions Ia, 8a, 9a, and I0 may be omitted and the reinforcing member secured in place by a tape.

In Figures 4, 5, and 6, I have shown a novel construction of a corner member, which not only strengthens the corner, but aids in securing the hollow reinforcements in place. These corner members may be made of metal stampings or of specially treated stifi paper board. As shown in Figure 5, the blank I2 is cut into a right angle shape at one end, as at I3 and is separated into a plurality of sections by suitable score lines. One side of the angle is separated from the other by means of the slot I4, and the end opposite I3 has a portion cut away as at I5.

When the blank is turned on the score lines the sections I6 and I1 are turned to engage the sides of the corner, as illustrated in Figure 4. Sections I8 and I9 are of the width as the distance from the outer to the inner side of the corner being reinforced, so that the sections 29 and 2I engage the inner corner sides, and sections 22 and 23 are turned into a position between the hollow reinforcing member and the main panel, as shown in Figure 6. Such a corner reinforcing, while adding considerably to the strength, will also be relatively cheap as no material is wasted since the next succeeding stamping will fit adjacent to the angle edge I3,

While I have described the corner reinforcements in connection with the blank of Figure 3, they can also be used with the blank of Figure 1. Also the panels from the blanks of Figure l and Figure 3 have been described as doors, and the slots Ila, IIb, and Ho have been shown for securing the door hinges with the hollow reinforcement; but it will readily be understood that the hinge slots may be omitted and the same general form of panel used for other purposes. As an example of other uses, the panel of Figure 4 could be used as a desk top in connection with my collapsible filing cases and drawers. Thus two low stacks of my casings would serve as desk supports with drawers on each side of a central opening, the drawers in each stack being interlocked to each other, as shown in my copending application Serial No. 693,841 and the top being interlocked to each stack of easing. For this adaptation sections 20 and 2| of the corner reinforcements may be provided with interlock slots as shown on the casing reinforcements in Serial No. 693,841 referred to above. A further use for the panels described above is as a top for a foldwhich define the main panel 35.

scores'are preferably ofth'e type disclosed in my shown a further modification in which the hollow edge reinforcement is spaced ashort distance from the edge of thepanel, thus providing a lip or flange aroundtheedge of the panel and extending outwardly from the hollow reinforcement' of the panel. Moreover, in these figures.

first turnedinto place on their respective score lines; Then either flap 31 or flap 39 is turned into place. The :following descriptionis re ferred to the flap 39, though it could applyina like'inanner to the flap 31. 1

' Whenthe flap is turned'on itsscore linesfthe tabs 39m and 39n will enter the slots 390 and the blank is so arranged that the edge reinforcements interlock with each other'in such a manner that when two of these reinforcementsare' properly secured, the other tworeinforcements are also held in place. i i

In these figures the blank has the double score lines am, 3lb; 32a, 32b; 33a, 33b; 3411,3412;

copending application entitled: End fold casing Serial No. 45,713 and filed coincidently with my parent application and copending with this ap-v plication, now'Patent 2,088,315, patented July 27; 1937. Extending from the main panel are the These double 3913 respectively These tabs are then pulled tight which will bring the entire structure into position and are then turned overthe flange 39;: as is v clearly shown in Figures 8'and 9'.

It will be noted that in this pos1 extensions on 'fiapsection 39b efie'ctively cover one end of each hollow structure formedby the flaps-36 and 38 and fitting respectively into the cut away portions 36h and 38g previously -de-- scribed. Also the extensions 39k: and 391 of sec 'tion' 3 9c'fit into the slots 387' and 382' respectively locking-over the upstanding portions '36d'and 38d flaps 36, 31', 3B; 39, which form the flanges around i the panels and the hollow reinforcin'g'me'mbers." Each of the flaps is provided with a number'for parallel score lines whichdivide each of the flaps into a number of sections. Thus fiap 36 has the attheir' end where they'meet the slots 369' and 382'. The'fiap 31 operatesinthe same manner, so

that the entire structure is effectively and simply; locked in its set upposition by the tabs on members'31 and'-39. 2-3

While two of these tabs are shown oneach flap 31 and 39, the number may be varied as required. Thus on a 'short- 'panel only one tab may: be needed, while on a longpanel more than two tabs may be required. I

score lines 310, Md, 3I-e, 3h; which define the sections 36 a, 3617,1330, and 33d, and Ste. Each of the flaps '31, 38 and 39; are similarly provided r with score lines which define similar sections of the respective'flap-s. w

It will be noted in Figure '7 that the flap sec:

tions 36a, 3M, 363a and 39a, terminate in a line at 45? tothe score lines' and that these 45 lines start at the ends of the double scores which de-" fine the'main panel 35; ,Thus whenthe'fiaps are folded vover as shown in Figure 8, the sections 360,,

31a, 33a. and 39a form aflange aroundthe panel'- 35 and meet each other in miter joints at the four corners; v i I Theflap 36 is cutback at-the sides starting at section-38b by a distance equal to the thickness I of the blank stock, asshown at 359 and 36h... Flap 38 is cut back in a similar manner. Section 360, which-in the folded position is parallel "to the panel 35, is providedwith slots 362' and 36y' of:

a length equal to the width of, sections 3-10 and 330, and of any desired'width. The purposes of these slots will be more fully explained later.

Now referring 7 like each other and which will be described by scores of section 39a. 7' Centered on this section are the sections 39c, sea-and 336, the two last mentionedsections being shorter than section 3919 by the width o'f'section iiiic plus the widthof The length of section 390 exceeds section .380. that of 390! or 39c by the'width ofjsl0t 367' plus or rivets. Between the double score line 34a and 342;, are the two slots SS and 39p eachspacedfl relative to the center line of thefpanel the same distance as are the tabs 29m and 35in. These slots are slightly larger than the cross sectional dimensionsof thetabs 39m and 3911.; I r r In setting up the panel, the flaps 33 and38 are to the flaps 3 and as whichare '{On the panels so far described,the reinforcing i membershave been quadrangular in cross" section In Figure'll, I have shown a form of blank from which a panel having reinforcing members oftriaiigular cross section may beproduced. In theFigure 40' representsthe blank. of material having the parallel score lines 4m, Mb, dlc; 42a,

414b, 44c,perpendicular thereto. Y

I The scores 41a, 42a, 43a, 44d define the main panel 45; which may be provided with-the min-.-

dle 46 shown of the type used with my filing drawerfand disclosedinmy Patent 1,946,516. Ex-

tendingfrom the main panel arethe flaps 41,58,

49, and: 50. These flaps are divided by. their ,re-.

spective score lines into the sections 41d,}-41b, I I m; 48a. 4811.480; 49:1,491149c; andiiia, 50b, 50c.

:Theblank of Figure ll'may be used with'a 1 base member such as shown in Figure 13 or 'Fi'gure '14; In Figure 12 there is shown the blank of- Figurellassembled in connection with the" "bas'e'inember' of Figure 14. I I a The 7 base member of'Figure l3- comprises a a blanlgof sheet -material 5210f the samedimen-"Q sio'ns asjfthe'finished panel. Thisblankhasth e "opening- 5 i qadapted-to register with th e'handle'. "46 whenthe panel is in set up position; 'Alongi theedgesfbf sheet'52 are thestrips'of; metal 53* predetermined; bending line 54 as 1 'de scribed in my copending application'Serial,;1 Io., .693', 8l1:;filed .Oct; 16,1933,- and the continua? tion' thereofel titledl Predet rmined bendline, Serial' No. 45710 and filed ooincidently with my parent application and copending with thisyap I referring specifically to flap 39. Flap secti0n 3 9b is of the same length as the shorter of the-two member, the blank 44!! is bent upon its score lines plication. Y'III assembling thepanel with this base and isfsuperposed upon the base 52; The metal strips 53"a're then bent on theirpredetermin'ed bendingl-ines 54 as shown in section inv Figurelfi.

securely unites thefolded blankg'fand the base member to form an integral structure.

j When vthe folded blank 4!} is used with the gbasemember of Figure 14, as shown-in perspective'lin Figure 12 and in cross section-in Figureil5, thehandle member 46 may be'omitted, even where a handle is'required; 'asf the base I as shown is provided withthe handle 56;

tion the end 7 Base member 55 is preferably of construction similar to that of the metal front disclosed in my copending application entitled: Drawer Serial No. 45,711 and filed coincidently with this application. It comprises the metal panel 55 having the integral frame 51 drawn from the metal of the panel 55. The frame 51 has the opening 58 in its center and this opening 58 has the flanges 59a, 59b, 59c and 59d at each of its edges. These flanges are of substantially the same height as the depth of the frame 51. Flanges 59a and 580 are provided with a slot 60a and (We respectively for the bent wire handle 56. Around the edges of the panel 55 are the U shaped flanges 6Ia, 6Ib, (He and Bld. Before setting up the assembled panel, these flanges are somewhat open.

In setting up the panel in connection with base 55 the blank 40 is bent on its score lines, and section 410 is inserted within flange BIb. Similarly section 490 is inserted within flange GId. Sections 480 and 500 are then inserted respectively into flanges Blc and Ma. The flanges are then bent down to clinch their respective flap sections as clearly shown in Figure 15. This not only firmly unites the two members into an integrated structure; but also the panel 45 being held against the outstanding edges of flanges 59a and 590 acts to retain the handle 56 in the slots 60a and 600.

In Figures 17, 18', and 19, I have shown a modified form of panel with reinforcing members of triangular cross section, but differing from the panel of Figure 11 in that the blank of Figure 17 forms a complete structure without a separate base member. In this figure I represents the blank of material having the parallel score lines Ila, H7), H0, 'Hd, He; 12a, 12?), 12C, 12d, 126;

and the score lines 73a, 13b, I30, 13d, I36; "Ida, 14b, I ls, Md, Me perpendicular thereto.

The double score lines Ila, 'IIb; 12a, 12b; 13a, 73b; and Ma, 1417 define the main panel I5. Extending from the main panel are the flaps IE, IT, I8 and I9. These flaps are divided by their respective score lines into the sections 16a, 16b, c, d; Ila, 17b, 11c, 11d; etc.

If the panel such as that shown in Figure 17 is to be used as a door it may be provided with the slots Ila, II b, and He for attaching a hinge portion to the door member, with the fastening means for the hinge within the side reinforcing member. The opening I Id provides means for mounting a handle within the outer side reinforcement with the handle protruding through the opening I Id.

Referring to the flap 18. The section 18a forms a flange as shown in Figures 18 and 19. The section 1819 forms the vertical member of the reinforcement, section 180 forms the sloping member; and section 180! forms a reentrant leg, which is preferably of sufi'icient length to extend between the panel member I5 and the flange member 18a. Section 18a is provided with extend flaps I80 and 130 which are marked off from the section I80 by suitable score lines.

The other flaps I6, TI and I9 are similar to flap I8 just described.

As shown the flaps are so cut that the reinforcements when folded into position meet each other at the corners in a miter joint.

Extending around the edge of the section I5 are the four strips of metal 80, 8|, 82, and 83 each formed with predetermined bending line 80a, 8Ia, 82a, and 83a, and so secured to the blank I0 that these bending lines are superposed over the double score defining the section I5. As

shown these predetermined bend lines are of the type as described in my copending application for Predetermined bend line, Serial No. 45,710, hereinbefore referred to.

In setting up the panel, each of the flaps is bent on the score lines to the position as shown in Figure 18. The metal strips are then turned on their bend line as shown at 82 in the same figure. In the set up position the extend flap 180' is in contact with the extended flap thus forming an added seal at the corner. Each of the four corners is thus double sealed in this manner.

Now referring to Figures 20, 21, and 22 there is shown a type of panel similar to that from the blank of Figure 17, except that the outer sections of the flaps are turned inwardly toward the center of the panel instead of outwardly toward the flange. Also the auxiliary flaps on the sloping portions have been omitted as have the metallic strips along the bending line. Thus the blank 90, of Figure 20 conforms to the blank I0 of Figure 17, except that the end sections 16f, Hi, 18 and 19] of the flaps of Figure 20 are trimmed on their edges to be folded inwardly instead of having the reentrant cut as shown on the outer sections 16d, 'I'Id, 18d, and 19d of Figure 1'7. When the blank of Figure 20 is folded into shape as shown in Figure 21, the flap sections 16 TI 18,1, 19), may be secured to the section I5 of the blank by adhesive or other means such as the rivets 9I, shown in Figure 21.

If the panel such as that shown in Figure 20 is to be used as a door it may be provided with the slots IIa, IIb, and He for attaching a hinge portion to the door member, with the fastening means for the hinge within the side reinforcing member. The opening IId provides means for mounting a handle within the other side reinforcement with the handle protruding through the opening I Id.

While in these forms of panel having a reinforcing member whose section is triangular, I have shown a right triangle whose right angle is toward the outer edge of the panel, it is quite obvious that by minor changes such as would be apparent to one skilled in the art, I can modify the flanks and the resulting panels so that the right angle is toward the center of the panel, or so that none of the angles of the triangle are right angles. Moreover, I can flatten off the apex of the triangle so that the hollow reinforcement is in cross section the form of a trapezoid, or a trapezium.

Thus, in Figures 23 and 24, I have shown a modification of the blank of Figure 20 to form a reinforcement wherein the cross section is that of a trapezoid having the inner wall I000, IOIc, I020, I030 perpendicular to the walls I001), "I011; IOIb, IOId; I02b; I02d; I03b, MM; and the panel face 99. This trapezoid section as shown in the Figures 23 and 24, starts at the edge of th panel, and does not have a flange around the panel as in Figures 20 and 21; but it will be readily understood that such a flange could be provided.

In Figures 25 and 26, I have shown a form of panel similar to that of Figure 11, except that side wings H0 and I II made respectively from the flaps IIOa, H01), and la, III?) of the blank I09. With wings such as areshown at H0 and III, the reinforced panel of the present application may b used with a form of metal facing I20 as shown in my copendingi application for Drawer, Serial No. 45,711, hereinbefore referred substantially equal to the thickness of the material. In this way, after the panel is bent into shape, as shown in Figure 25, the flap IIIlb will be flush with flap H6; and flap III!) will be flush with 'flap I I1. I

It will of course be understood that the other forms which I have shown may be provided with side wings in a manner similar to that shown in Figures 25 and 26.

Moreover, it will be further understood that the particular forms described in this application are by way of illustration and that many changes in details may be made without departing from thescope and spirit of my invention as set forth in the attached claims.

Now having clearly described my invention so that it may be readily understood by'one skilled in the art, I claim: v f

l. A panel comprising a blank of sheet material having fold lines along which said blank is manually foldable, flaps integral with said blank foldable to form reinforcedpedges of hollow constructionfor'said panel; extensions on one of said flaps and slots on an adjacent flap arranged to interlock with the flaps in thefolded position; whereby when one of said flaps is secured in position as a hollow reinforcing memher; the other of said flaps is also secured in position as a hollow reinforcing member.

2. A panel comprising a blank of sheet material having fold linesalong which said blank is manually foldable, flaps integral with said blank foldable to form reinforced edges of hollow construction for said panel; extensions on one. of said flaps, and s10tS'0l'1 an adjacent flap arranged to interlock withthe flaps in the folded position; I whereby when one of said flaps is secured in position as a hollow reinforcing member, the

' arranged to interlock with the fiapsin thefolded as a hollow reinforcing member; a strap secured to the extremityof one'of the'fiaps' and a slot in the same flap for admitting said strap. I r

3. A panel. comprising a blank of'sheet'material having fold lines along which said blank I is manually foldable, flapsiintegral with said blank foldable to form reinforced edges of hollow construction for'said panel; extensions on one of saidflaps and slotson an adjacent flap position; whereby when one of said; flaps is secured in position as a hollow reinforcin mems ber, theother of said flaps is also-secured in position as a hollow reinforcing member; and extensions on one of said flapsarranged to form end walls on adjacent hollow reinforcing members.

' 4. A panel comprising a;blanki of sheet mate; rial having fold lines alongwhich saidblank is manually foldable; flaps integral with said blank foldable to form reinforced edges of hollow construction for said panel; extensions on one of i said flaps and slots on an adjacent flap arranged to interlock with the flaps in the folded position;

outwardlyfrom said reinforcements. I v

5. A panel comprising a blank of sheet mate rial havingffold lines along which said blank is manually foldable; flaps integral with said blank foldable to form reinforced edges of hollow construction for said panels; extensions on one'of j. saidfiaps and slots on an-adjacent flap arranged to interlock with theflaps in the foldedjposition;

whereby when one of said flaps is'se'cured in position as a hollow reinforcingv member, the other of said flaps is also secured in'positionas a hollow'reinforcing member; flanges protruding outa 1 wardly from" said reinforcements; and a metallic U-shaped base member bent; around the periphery for enfolding said protruding flanges.

I PHILIP ZALKIND;

other of said flaps is also secureddin position

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