US2371754A - Stiffened material - Google Patents

Description

March 20, D E. GILLUM ET AL STTFFENED MATERIAL` Filed April `2.2, 1942 2 Sheets-Sheet l i k A j W y L *J 12 WIG.

Y C: [i672 2f j ,mg Rf@ March 2o, 1945. D. E GILLUM ETA'L 2,371,754`

l STFFENED MATERIAL. l

Filed April 22, 1942 2 Sheets-Sheet 2 ATTORNEY partV of the skin of an airplane.

Patented Mar. 20, 194.5

STIFFENED MATERIAL t Donald E. Gillum, vHermosa Beach, and Dale .I

Van Riper, Los Angeles, Calif., assignors to North American Aviation, Calif., a corporation o! Delaware Inc., Inglewood,

Application April 22, 1942,`Seral No. 440,040 6 claims. (ci. 18o-34') in aircraft, automobiles, railroad cars, and alll other fabricated articles or machines embodying a surface or similar part thereof that is subject to vibration or bending inuences.

Further objects reside in the provision of a material that is easily fabricated, relatively inexpensive to manufacture, easily used in assembling other articles, serviceable and of. general superiority. v

The following description merely, describes and the accompanying drawings merely show embodiments or suggested forms, and are not to be taken. as the only possible embodiments or forms.

' In the drawings, like reference characters designate similar parts in the several views.

Fig. 1 is a perspective `view of material made in accordance with the present invention employed, as a leading edge of an airplane Wing.

Fig. 2 is a plan view of a portion of such material, broken away.`

Fig. 3 is an enlarged section taken on the line 3 3 of Fig. 2.

Fig. 4 is an enlarged section taken on the line 4 4 of Fig. 2.

Fig. 5 is a view similar to Fig, 4, but showing a modiiied construction.

Figs. 6 to 13 are plan views of modied arrangements of the stilening means.

Fig. 14 is a sectional view taken along the line Ill-I4 of Fig. 11, showing a still different cross sectional shape for the wire.

Referring more in detail to the drawings, the reference numberI I2 generally designates the sheet material, which in Fig. 1 is shown as the The sheet materialY I2 may be of steel, aluminum, etc. `In Fig. 1, stringers or strengthening members I3 are suggested, for reenforcing the wing I4.

Irib l5 is also indicated in that figure.

The stiiening means for the sheet material I2 is preferably wire, but it may be of any desired arrangement of wire running in directions at angles toeach other. The wire may also be in the form of a mesh.

In Sheet I of the drawings, the wires are shown A bracing forming rectangles and extend substantially parallel with the sides and ends of the sheet material. It is believed-clear that the present stifened material may be formed by-any of the following processes: seam welding, spot welding, brazing, cementing, are welding, or the like.

Spot welding has been suggested in Figs. 2 to 4. Spot welding may of course be-v done by any suitable gang or gangs of spot welding electrodes. A suggested apparatus has been illustrated in our pending application fi, 1942.

Longitudinal wires I6 are crossed by transverse wires Il on the back of the sheet material I2. Upon thepoint of the crossing over of one wire by another sufilcient heat and pressure are apl plied by the welding electrode to cause the two Fig. 5 illustratesgwires 20 of modied cross-l section, to wit, rectangular. The rectangular wires 20 are welded together at their intersections and Welded to the sheet metal I2 at such, intersections, just as the round wire.

Fig. 6 shows tubular wires 2 I, which are utilized the same as the round, solid wires hereinbefore described.` The tubular wires still further lower the weight-stiffness ratio of the nished material.

Fig. '7 illustrates solid wires 22 of irregular cross.

section. Converging flat sides 23 increase the resistance of the wires 22 to bending. Thetop I9 of the wires 22 may be nat, while the curved bottom may be fused to the sheet material I2. Although there is the same amount of metal in the wire 22 as in a round wire having a diameter equal to the lower, curved portion of the `wire 22, the cross section of the wire 22 has aconsiderably higher neutral axis than the neutral axis of round wire having a diameter equalg'to the lower, curved portion of wire 22. The wire 22, therefore, has more stiines's than round wire having the same amount of material.

Fig. 8 shows metal rings 24 that are simultaneously welded to each other and to the sheet material, as suggested at 25.

Fig. 9 illustrates ellipses 26 with smaller rings 21 connecting rows of the ellipses with each other.

Serial No. 445,822, led June I `This arrangement of ellipses and rings may be prefabricated and such prefabricated arrangement welded upon a face of .the sheet material l2 for strengthening purposes. It will be noted that there are considerably more wires crossed by the broken line 34 than by the broken line 35,

thus the direction of greatest rigidity can be controlled, for there is greater resistance to bending along the line 34 than along the line 35. By this arrangement, the sheet material is stiilened in one direction more than the other.

Fig. shows series of rosettes 28 which may be Prefabricated and such prefabrication layed upon the sheet l2 and welded in place.

Fig. l1 is similar to the arrangement shown in Figs. 1 and 2, but showing a diagonal arrangement of wires 29 upon the sheet I2. l

Fig. 12 shows angularly bent wires 30 that are layed adjacent each other and welded in place upon the sheet material I2. This arrangement can be used to control the direction of greatest rigidity as in the case of the form in Fig. 9.

Fig. 13 shows a hexagonal form 3l that is prefabricated andthen applied to the sheet I2 and welded in place.

Fig. 14 shows a modified I-beam construction that may be used for the wires. This gure is taken along theline H-I'l of Fig. 11.

It is to be understood that the `word Wmr in the present description and inthe hereunto appended claims shall include both drawn material and extruded material and differentcross sectional shapes, and shall include both solid and hollow forms. Moreover, ,welded shall be taken to include not only spot and seam welding which comprises joining together by fusing abutting surfaces with or without the addition of extra metal, but also brazing, cementing and arc welding.

Any of our present materials may be produced by mass production methods, and such material have many uses in the fabrication of aircraft,

automobiles, railroad cars, etc.

While we have illustrated and described what l claim and desire to secure by Letters Patent is:-

1. An article of manufacture comprising a section of sheet metal presenting a continuously un` broken surface at one side thereof, and a reenforcing and vibration reducing web of wire elements on the other surface thereof, said elements being in individually complete units of a closed. .curved shape in plan view and presenting Contlnuously curved perimeters, integrally joined to one another and to the sheet metal surface at spaced points along the perimeters thereof.

2. As an article of manufacture, a skin covering for vairplanes and airships, consisting of a single layer of sheet metal presenting an external unbroken surface, and reenforcing wire elements in individually complete geometrical units of a closed, curved shape in plan view and disposed with their perimeters in touching relation and welded to one another and to the other surface of the plate at said touching points.

3. An article of manufacture, consisting of sheet metal, and reenforcing wire elements disposed against a surface of said sheet metal in individually complete units of a closed, curved shape in plan view and presenting curved perimeters in touching relation at spaced points therearound, and substantially integrally joined at said spaced touching points to one another and to the sheet metal. f

4. An article of manufacture, consisting of sheet metal, and a surface layer of peripherally touching individually complete wire elements in individually complete units, said units being of closed, curved shape in plan view and being alternately of ovate and circular form in successive rows, the circular units being disposed between the smaller ends of the ovate units, and all of said units being substantially integrally joined to one another and to the sheet metal at the points of touching of the units.

5. An article of manufacture comprising a sheet metal layer and reenforcing elements consisting of L wire-like ribs presenting cross sectionally thereof rounded basal edges substantially integrally joined to and across a surface of said sheet metal layer, and straight side edges converging from said rounded basal edge to a free edge.

6. An article of' manufacture comprising a sheet metal member, and wires arranged in individually complete, and elongated units of a closed curved shape in plan view, and disposed on the metal member with the elongations extending substantially in the same direction on the sheetV metal member to provide greater resistance to bending on a line transverse to the elongations than parallel with the elongations, and the wires being substantially integrally joined. to one another and to the sheet metal member at a side thereof.

`DONALD- E. GILLUM. DALE H.v VAN RIPER.

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