US2078425A - Structural unit - Google Patents

Description

v April 27, 1937. w. H. sTULl-:N

STRUCTURAL UNIT Filed Sept. 9, 1936 2 Sheets-Sheet 1 April 27, 1937. w. H. sTULEN STRUCTURAL UNIT 2 Sheets-Sheet 2 Filed Sept. 9, 1956 INVENTOR. Wina fau.

b1 ATTOINEYS.

Patented Apr. 27, 1937 UNITED STATES PATENT OFFICE STRUCTURAL UNIT y Walter H. Stulen, Pittsburgh, Pa. Application September 9, 1936, Serial No. 99,931

12 Claims.

This invention relates to structural units, and particularly to those made in whole or in part of sheet metal, and constitutes an addition to and improvement on the units disclosed and claimed in my copending applications, Serial No. 13,868, led March 30, 1935, and Serial No. 86,367, iiled June 20, 1936.

Heretofore the usual structural unit of metal has been made from rolled metal sections such as I-beams, angles, channels, etc., of considerable weight and cross-sectional areas dependent, oi' course, upon the load to which it isV subjected. Likewise structural units comprising combinations of channels, angles, plates and bars have been provided. These structural units are, however, particularly adapted to heavy and concentrated loads and tothe erection of a skeleton framework `type of structure. They necessitate considerable fabrication labor and are not capable of use in the construction of so-called frameless buildings.

As more particularly described in my copending applications referred to above, I have provided structural units made from sheet metal which particularly adapt themselves to the construction of the frameless type of buildings, that is, buildings in which the skeleton frame is eliminated, and the inherent strength and rigidity of the units forming the floors, walls, and ceilings proper of a building function as a whole to provide a continuous frame or sometimes termed a frameless structure. The sheet metal structural units of my present invention and also of my copending applications are particularly adapted to the construction of houses, stores, garages, and the like, and unlike the independently acting structural units made of rolled metal sections are relatively inexpensive to manufacture and fabricate. Furthermore, their use results in a structure having a true frameless appearance, since the sheet metal actually covers so much of the space, while retaining the advantages of the open construction of the rolled metal section unit. These advantages include ease of securing metal lath, wood or other finishing material to the frameless structure and accessibility to receive and carry electric, gas, water and other conduits in the Walls, floors and ceilings of the structure.

It is the general object of my. invention to avoid and overcome the foregoing and otherditculties of known rolled metal sections and to improve upon sheet metal structural units bythe provision of a sheet metal structural unit having the metal shaped Vand positioned to best resist and carry compressive, tensile and torsional stresses to which it is subjected in use.

Another object of my invention is to provide an improved type of tapered structural unit.

y Another object of my invention is the provision of a structural sheet metal unit having the sheet u metal in the form of periodically repeated diamond-shaped areas of unbalanced or distorted, shape in plan.

While in accordance with known engineering principles, the structural units of my referred-to copending applications can be adapted to carry substantially any desired loads on spans of particular dimensions, I have discovered that the inherent strength of a unit employing the same gauge of sheet metal and having the same height and width can be increased by rearranging the shape of the sheet metal to better adapt it to stresses to which it is subjected. Broadly, the portions of the metal subjected to compression are shortened vso as to render them more rigid, whereas the portions subjected to tension are lengthened without weakening them to thereby allow the compression portions to be shortened.

Specifically, I provide a structural unit comprising a longitudinally extending strip of sheet metal bent along a longitudinal center to form portions making an angle of less than with each other. The portions are formed with laterally extending triangular areas lying in the same planes as the portions with the rareas being continuously repeated longitudinally of the strip and having one unsupported side of each triangular area of less length than the other unsupported side. The shorter unsupported sides are positioned away from the nearest end of the unit so that each half of the length of the unit appears the same when looking from the middle to the ends of the unit. Further incorporated with the unit are longitudinally vextending strengthening means, such as rolled metal sections, which are secured to the apexes of the triangular areas and to the center of the strip with boundary channels receiving the ends of the unit.

For .a better Aunderstanding of the invention reference should be had to the accompanying drawings wherein Fig. 1 diagrammatically illustrates the principles of my present invention; Fig. 2 further illustrates the principles diagrammatically Vshown in Fig. 1; Fig. 3 is a plan View of a structural unit incorporating the features of my invention; Fig. 4 is a transverse cross-sectional view taken on line IV-IV of Fig. 3; Fig. 5 is a View similar to Fig. 4 but of a modified form of. cross-sectional shape for the unit; Fig. 6 is an.

enlarge'd cross-sectional View taken on line VI-VI of Fig. 3; Fig. 7 is a view similar to Fig. 3 but of a modified form of my invention; Fig. 8 is a view similar to Figs. 3 and 7 but of a further embodiment of the invention; Fig. 9 is a plan View of a tapered structural unit incorporating the principles of my invention; and Fig. 10 is a cross-sectional View taken on line X-X of Fig. 9.

As referred to above, in their broadest aspects my inventions upon sheet metal structural units contemplate the use of sheet metal strip having triangular laterally extending areas periodically repeated longitudinally of a strip with the strip bent along a central longitudinal to define an open-sided triangle in cross section and having longitudinally extending strengthening means secured to the central longitudinal and the edges of the strip. Thus in Fig. l I have illustrated diagrammatically a base line lil which comprises a longitudinally extending line parallel to the center of a strip of sheet metal which line forms the base for the construction of laterally extending and periodically repeated triangular areas. The base line lil is divided into longitudinally repeated lengths such as indicated by the dimension M, which stands for module. As fully described in my copending application, Serial No. 13,868, filed March 30, 1935, the sheet metal structural units of my several inventions are preferably constructed on longitudinally repeated bases of a module length and the units are ordinarily of a module width. In Fig. 1 the widths of certain triangular areas have been indicated by the dimensions M which ordinarily are approximately one-half M. Now, if a ilexible cord is connected to the base line Iii at the ends of the module M and extends likewise to the point I4, a curved semi-e1liptical-line I6 can be generated by engaging a pencil in the cord and moving the pencil in both directions guided and conned by the cord.

The change in shape and area of the area bounded by the base line I0 and the cord during the generation of line I6 aptly illustrates the possible changes in shape and area of the triangular areas or portions which I may employ upon my sheet metal strip used in a structural unit. In Fig. 1 the several dotted lines dening triangular areas having the common base of M length on the base line l0 are diagrammatically illustrative of the possible triangular shapes which I may employ. In actual practice, instead of employing the cord to generate a semi-elliptical I6, I provide a base line 26, as shown in Fig. 2, having a boundary line 22 spaced a distance M or slightly less than one-half module therefrom. On the base line 23 a distance M substantially equal to or slightly greater than two M is selected, and any sized and shaped triangular area, such as those dened by the dotted lines, can be drawn upon the base line 26 but in each case the apex of the triangle engages with the boundary line 22. The distance M of the base of the triangle may be the greatest side of the triangle or as shown by the dotted line 24 a triangle having a side greater than the distance M can be constructed, as hereinafter more fully explained.

The dotted line 26 indicates the standard isosceles triangular area as employed in my copending application, Serial No. 13,868. The dotted line 28 defines a triangular area having one unsupported side relatively short and the other unsupported side of the area being relatively long. By unsupported. I mean the sides ofthe triangular area other than the base. I have found that compression stresses are handled by the relatively short unsupported side of the triangular area with less danger of buckling than when the compression stresses are handled by the unsupported side of the isosceles triangular area indicated by the numeral 2E, all as hereinafter explained.

Referring to Figs. 3 and 4 of the drawings, the numeral 3U indicates a strip of sheet metal of any desired gauge dependent, of course, upon the load to which the structural unit is subjected. The strip 30 is bent along a central longitudinal line 32 to an angle of less than 180 degrees and is formed with longitudinally repeated bator wing-shaped triangular areas 34 which, as will be evident from the drawings, lie in the same plane asl their associated portions on each side of the line 32 and are integral with the remainder of the strip 36. The particular angle between the portions of the strip formed by the bend along the center line 32 is dependent upon the particular depth and width desired in the unit but with a unit 18" wide and adapted to span 20 feet and carry a load of 50 pounds per square foot, I employ an angle of between 90 and 120 degrees with a resulting depth in the unit of from 6 to 9 inches. The sheet metal employed in the stated example is of 16 gauge.

From Fig. 3 it will be seen that each triangular area 34 of the sheet metal 30 is formed with a relatively long, unsupported side 36 and a relatively short, unsupported side 38, so that the resulting triangular areas are quite similar to the area defined by the dotted line 28 in Fig. 2. The short sides 38 of the triangular areas 34 are placed away from the nearest ends of the unit and meet at the center to provide a structural unit which has oppositely positioned triangular areas thereby providing a balanced construction. I contemplate making each unit of two pieces of strip or sheet metal cut to form as a single strip by cutting rolls, then cut in two and one piece turned end to end. This facilitates manufacture as will be evident. I have found that when the structural unit of Figs. 3 and 4 is positioned horizontally and is loaded, compression occurs in the relatively short, unsupported sides 38 of the triangular areas which are particularly adapted because of their shortness to withstand these stresses. The relatively long, unsupported sides 36 of the triangular areas are subjected to ten- Sonal stresses in the use of the unit and since no buckling thereof occurs in tension, they are adapted to readily withstand the stresses. To further assist in preventing buckling due to compression, I may provide the short, unsupported edges 38 of the triangular areas with an upstanding flange 40 as shown in Fig. 6. In many installations this is not essential, for example, where the unit is positioned vertically, as in a wall. Even the necessity for positioning the short, unsupported sides of the areas toward the center of the unit may be eliminated if the units are to be used where they are not subject to bending stresses.

Completing the structural unit, I weld or otherwise secure'longitudinally extending strengthening angles 42, 43 and 44 tothe center and edges, respectively, of the sheet metal strip 30, which angles may be rolled metal sections. Flat metal strips or ties 45 are welded or otherwise secured to the unit in transverse positions to prevent the base'ofA the unit from increasing in width. Theresulting unit is triangular in cross section and is received at' its-'endsin' boundary channels 46, which are welded or otherwise fastened to. the unit, and the result is a composite structure largely constructed of sheet metal whichis particularly adapted when built into panels to be used in the construction of frameless buildings but which more broadly is applicable to the manufacture of substantially any desired loadbearing or non-load-bearing structural body. The particular shapev of the triangular portions 34 of the sheet metal strip 30 adapts the unit to better handle relatively heavyy loads when in horizontal or somewhat inclined positions as will be understood.

In Fig. I have illustrated a modified form of cross section for the structural unit of Figs. 3 and 4 wherein the sheet metal-strip 30 is formed with a flat central portion 48 and parallel flat edges 50 to whichare welded or otherwise fas-v tened angles 52 and transverse tie straps 53.- In certain instances it is advisable to employ the angles 52 as shown in Fig. 5 rather than the angles 42, 43 and 44 of Fig. 4, since angles are stronger when employed so that their flanges are parallel to the direction of stress; however, where the angles are in tension as are angles 43 and 44 with the unit horizontal the shape or position of the angles is not as important as where they carry compression stresses.

The embodiment of my invention shown in Fig. '7 is substantially the same as that shown in Fig. B'with the exception that the bator wing-shaped triangular areas 34 of Fig. 3 have been changed to obtuse triangular areas 60, which together form substantially heart-shaped sheet metal areas which are periodically repeated longitudinally of the unit, although' as in Fig. 3 the areas have their shorter, unsupported sides towards the center of the unit. More specifically the dotted area defined by the line 24 in Fig. 2 is the shape employed in the unit of Fig. 7. In this unit the compression stresses upon the sheet metal strip aretaken by relatively short, unsupported sides 62 of the triangular areas whereas the tensional stresses are`= taken by the relatively long, unsupported sides 64. Transverse tie straps 65 and'boundary channels 66 complete the unit. The exact cross section of the form of my invention shown in Fig. 'l is not essential and either of the sections shown in Fig. 4 or 5 can be employed.

In Fig. 8 I have illustrated a structural unit quite similar to that shown in Fig. 3 with the exception that the triangular areas 34a instead of being laterally opposite to each other as in Fig. 3 are longitudinally oiset with respect to each other so that the triangular areas 34a. on one side of the line of bend 32a are midway between the triangular areas 34a on the other side of the line of bend. Transverse tie straps 45a and boundary channels 46a are preferably included in the assembly. The resulting structure appears in cross section the same as the unit of Fig. 3, as will be understood.

To further illustrate the Yversatility of my invention I have shown in Fig. 9 a tapered unit including a tapered strip ll) of sheet metal formed similarly to that shown in Fig. 3 and described in detail above with the exception that the angles 43 and 44 of Fig. 3 extend parallel to each other whereas angles 43a and 44a of Fig. 9 converge towards each other. A longitudinally extending strengthening member 420. is employed at the center of the tapered unit and transverse ties ll and a channel l2 complete the unit. The

resulting unit is adapted for vvarious structural purposes, as for example columns with two of the units being secured back to back.

It will be seen from the foregoing that the objects Yof my invention have been achieved by the provision of an improved type of sheet metal structural unit particularly adapted for the fabrication of irameless buildings. The sheet metal is shaped and positioned to best carry compression and tensile stresses while retaining its inherent sheet metal characteristics.

While in accordance with the patent statutes, several embodiments of my invention have been illustrated and described in detail, it should be understood that the invention is not limited thereto or thereby but is dened in the appended claims.

I claim:

1. A structural unit comprising a longitudinally extending strip of sheet metal bent along a central longitudinal to form portions making an angle of less than 180 with each other, said portions having laterally extending triangular areas formed integrally therewith and in the same plane, said areas being continuously repeated longitudinally of the strip and having one unsupported side of each triangular area of less length than the other unsupported side, said shorter unsupported sides being positioned away from the ends of the strip, longitudinally extending strengthening means secured to the apexes of the triangular areas and to the center of the strip, and boundary channels receiving the ends of the unit.

2. A structural unit comprising a longitudinally extending strip of sheet metal bent along a central longitudinal to form portions making an angle of less than 180 with each other, said portions having laterally extending triangular areas formed integrally therewith and in the same plane, said areas being continuously repeated longitudinally of the strip and having one unsupported side of each triangular area of less length than the other unsupported side, and formed with an upturned flange, said shorter unsupported sid-es being positioned away from the ends of the strip, parallel longitudinally extending strengthening means secured to the apexes of the triangular areas and to the center of the strip, and boundary channels receiving the ends of the unit.

3. A structural unit comprising a longitudinally extending strip of sheet metal bent along a central longitudinal toform portions making an angle of less than 180 with each other, said portions having laterally extending triangular areas formed integrally therewith and in the same plane, each of said triangular areas having one side shorter than the other side, said areas being continuously repeated longitudinally of the strip, longitudinally extending strengthening means secured to the apexes of the triangular areas and to the center of the strip, and boundary channels receiving the ends of the unit.

4. A structural unit comprising a longitudinally extending strip of sheet metal bent along a central longitudinal to form portions making an angle with each other, said portions having laterally extending triangular areas formed integrally therewith and in the same plane, said areas being continuously repeated longitudinally of the strip and having one unsupported side of each triangular area of less length than the other unsupported side, longitudinally extending strengthening means secured to the apexes of the triangular areas and to the center of the strip,

and boundary channels receiving the ends of the unit.

5. A structural unit comprising a longitudinally extending tapered strip of sheet metal bent along a central longitudinal to form portions making an angle With each other, said portions having laterally extending triangular areas formed integrally therewith and in the same plane, said areas being continuously repeated longitudinally of the strip and having one unsupported side of each triangular area of less length than the other unsupported side, and converging longitudinally extending strengthening means secured to the apexes of the triangular areas and to the center of the strip.

6. A structural unit comprising a plurality of longitudinally connected polygonal areas of sheet metal, each of said areas before bending including a pair of isosceles triangles having diierent altitudes but a common base, each of the shorter altitude triangles being positioned away from the nearest end of the unit, said longitudinally connected areas being bent along a central line perpendicular to the common bases to form in cross section an open-sided triangle, longitudinally extending strengthening means angular in cross section secured to the sheet metal along the central line and at the edges thereof, and channels receiving and secured to the ends of the unit.

7. A structural unit comprising a plurality of longitudinally connected polygonal areas of sheet metal, each of said areas when at including a pair of isosceles triangles having diierent altitudes but a common base, each of the sho-rter altitude triangles being positioned away from the nearest end of the unit, said longitudinally connected areas being bent along a central line perpendicular to the common bases to form in cross section an open-sided triangle, and longitudinally extending strengthening means angular in cross section secured to the sheet metal along the central line and at the edges thereof.

8. A structural unit comprising a plurality of longitudinally connected polygonal areas of sheet metal, each of said areas when flat including a pair of isosceles triangles having different altitudes but a common base, each of the shorter altitude triangles being positioned away from the nearest end of the unit, said longitudinally connected areas being bent along a central line to form in cross section an open-sided triangle, and longitudinally extending strengthening means secured to the sheet metal along the central line and at the edges thereof.

9. A structural unit comprising a plurality of longitudinally connected polygonal areas of sheet metal, each of said areas when flat being heartshaped With the notch of the heart being positioned away fro-m the nearest end of the unit, said longitudinally connected areas being bent along a central line to from in cross section an open-sided triangle, and longitudinally extending strengthening means secured to the sheet metal along the central line and at the edges thereof.

10. A tapered structural unit comprising a plurality of longitudinally connected polygonal areas of sheet metal, each of said areas being of progressively smaller size, said longitudinally connected areas being bent along a central line to4 form in cross section an open-sided triangle, and longitudinally extending strengthening means secured to the sheet metal along the central line and at the edges thereof.

11. A structural unit comprising a plurality of longitudinally connected polygonal areas of sheet metal, each of said areas when flat being heart-shaped, said longitudinally connected areas being bent along a central line to form in cross section an open-sided triangle, and longitudinally extending strengthening means secured to the sheet metal along the central line and at the edges thereof.

12. A structural unit comprising a strip of sheet metal bent along a central longitudinal, triangular areas formed on the edges of the strip in longitudinally repeated sequence, each area having a shorter, unsupported side and a longer, unsupported side, the shorter sides being positioned away from the nearest end of the unit, the areas on one side of the strip being approximately half-Way between the areas on the other side of the strip, and longitudinally extending strengthening means secured to the center and edges of the strip.

WALTER H. STULEN.

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