US2068052A - Joist - Google Patents

Description

Jan. 19, 1937.

E. D. cQDDlNGToN JoIsT Filed Sept. 3, 19555v my L Patented Jan. 19, 1937 UNITED STATES PATENT OFFICE JOIST Application september 3, 1935, serian No. 39,028

6 Claims.

The present invention has to do with a fabricated metal and concrete joist.

vThe objects of the invention include, among others, the provision of the following:

hereinafter appear, are obtained by the novel.

construction, unique arrangement, and improved combination of the several elements which constitute the invention, one embodiment of which is illustrated inl the accompanying single sheet of drawing, hereby made a part of this specification, and in which:

Figure 1 is a side elevation of a joist embodying the subject matter of the present invention;

Figure 2 is a transverse section on the line 2-2 of Figure 1;

Figure 3 is a transverse section on the line 3-3 of Figure 2;

Figure 4 is a transverse section on the line 4-4 of Figure 1; and

Figure 5 is a sectional detail taken on the line 5-5 of Figure 1.

Like reference numerals are used to indicate similar parts in the drawing and in the description of the invention which hereinafter is given.

The improved joist herein described and illustrated comprises a top chord I0, a bottom chord II, an end member I2, and an intermediate web member I3.

The top and bottom chords I0 and I I are identical but reversed. Said members comprise a U-shaped channel member I4 of suitable metallic material having a narrow interior portion I5, a flaring side I6, and a second flaring side I'I, the shape of which is reversed to that of the side I6. The sides I6 and' I1 define at their edges anges which terminate parallel to the transverse interior portion I5.

Across the open side of the channel member I4 is a flat sheet of material I8 generally of the same width as the channel member from the edge of one flange to the edge of the opposite flange. This closure member or flat strip of metal I8 is joined to the U-shaped member I4 along its edge by a series of spot welds or in any other suitable manner.

The two metal members comprising the parts I4 and I8 thus together dene an elongated tube. 55 The opposite chord II of the joist is of an iden- A skeletonized metallic joist intokr which nails (Cl. 18S-37) tical structure and comprises a channel member having a flat base, sides with flanges and a metal strip; covering, the position of the parts being reversed to those of the rst described chord I0. The first referred to U-shaped chord I0 and the second referred to U-shaped Achord II are each filled with cementitious material forming a core 20. This core may be composed of a mixture of gypsum, Portland cement and sawdust, represented in the proportions, by weight, 55:20:9. This mixture is packed into the casings in a dry state and moisture then introduced through openings I9 (Fig. 2.) Vformed in and throughout the length of the closure strip, to supply the necessary lWater of crystallization to harden the material. This process of fabrication is described and claimed in my copending application Serial No. 39,022. Of course any other suitable llers or processes of fabrication may be employed.

The U-shaped chords I0 and II arearranged in parallelism with their ends terminating in alinement. The chords I0 and II are of predetermined standard lengths. An end member I2 is disposed at each end of the joist and intermediate the end members I2 is a reenforcing and spacing web I3. The web comprises two elongated arcuate members oppositely disposed, the arcuate members being indicated 23 and 24 and being joined at their centers and contacting surfaces by spot welding 22 (Fig. 5). Members 23 and 24 after attachment one to another are folded at predetermined intervals along their length.

At the folded sections, the members 23 and 24 are attened to provide a surface that will lie flat against the inner sides of chords I0 or II. In the structure illustrated in Figure 1, obliquely disposed sections of web I3 are indicated by the numerals 25. The flattened out portions of the web I3 lying against the chord II are designated 26 and the flattened portions lying against the chord I0 are indicated 2l. The length of the members 23 and 24 is determined by the length of the chords III and Il, and by the length of the end members I2 now to be described in detail.

The end members I2 overlie a flattened extension 28 of the Web I3. Each end member I2 comprises an exposed side or end 30, a side 3l contacting the inner surface of chord I0, a side 32 at the interior of the joist, and a side 33 contacting the web extension 28. The sides 30, 3|, 32, and 33 form a rectangle and will be ordinarily made of a single strip of material.

Two dish shaped members 36 and 38 having, respectively, peripheral flanges 31 and 39 are telescoped into the opposite sides of the rectangular frame of the end member I2. Spot Welding 40 may be used to maintain the member 36 in position. It is customary to ll member I2 with a cementitious material which will receive nails driven thereinto, such concrete fill being indicated by the numeral 42. Member 38 is secured in position by spot Welding 4I after the ll 42 has been inserted.

The joist generally is assembled by inserting between the chords I0 and II the web I3, and thereafter inserting the end members I2. All of the parts are secured in position by spot welding'. Plate 36 is then tted into position if not previously inserted and welded. As previously stated, end member I2 at its bottom side overlies a at end section 28 of the web I3. Member I2 is attached to chord I0 and web extension 28 by Aspot Welding 43 and 44, and web I3 is secured to chords I0 and II by welds 45 and 46.

The iill for the end members I2 may be inserted Vafter said members are spot welded to the chords II! and II, and chords ID and II may be filled after all spot Welding has been completed except the welding of side piece 38 tov member I2, which is attached after the lls are inserted.

The structure described is exceedingly strong. The web comprising opposed arcuate strips joined along their longitudinal lines and flattened out at spaced intervals for attachment to chords I0 and II resists both compressing and torsional 'strains to a remarkable degree when the weight of the structure is considered. The chords and end members readily receive nails and may be used as, and in place of wooden joists. The joist 'is simple to fabricate and the cost of assembly and materials is relatively low.

I claim:

1. A metal and nailable concrete joist comprising spaced apart composition filled chords, and a web therebetween comprising paired opposed arcuate members.

vengaging the chords at spaced intervals, the sections of said strips contacting said chords being iiat and the intermediate sections of said web comprising opposed arcuate channels joined one to another along their longitudinal median lines.

5. ,A metal and concrete jost comprising channel shaped chords iill'ed with a nailable composition, and a web therebetween, said web comprising paired longitudinal strips joined one to another lat their longitudinal median lines, said strips having ilat portions contacting the inner faces of said chords, and being substantially X-shaped in cross-section between said contacting portions.

6. A joist comprising opposed U-shaped metal chords ofchannel shape covered with a Vmetal strip at their edges and iilled with a nailable composition, parallelopiped end members of metal and a nailable composition between said chords,

and a web between said chords extending unbrokenly from one end memberto the other end member, said Web comprising a pair of elongated strips arcuate in cross section and joined one to another at their longitudinal median line, said strips being folded alternately in one direction and then the other and being joined at succeeding folds to opposite chords.

EDWDT D. CODDINGTON.

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