US2147965A - Bar joist - Google Patents

Description

J. A. cLAuss- 2,147,965

Feb. 21, 1939.

BAR JOIST Filed April 5, 1938 T$..N N R 2 m4 T Z A I H v 5 .a & MM

Patented Feb. 21, 1939 BAR J'oIs'r Julius A. Clause, Detroit, Micla, assignor to Great Lakes Steel Corporation, Eeorse, Mich, a comration of Delaware Application April 5, ma, Serial No. 200,214

Claims.

This invention relates to bar joists and the principal object is the provision of a joist of this type that is light in weight in comparison to its strength, that is simple, cheap and economical 5 to build and use.

Other objects of the invention include the provision of a bar joist of all metallic construction to the upper and lower faces of which his possible to secure other parts by nailing them directly thereto; the provision of -a bar joist having upper and lower chords formed fromangie sectioned members arranged in back-to-bacir relationship, the inner marginal edges 01' the opposed flanges being flared or flanged outwardly-to provide a groove or recess therein for reception of the bar or web; the provision of a bar joist of the type described in which the web comprises a continuous bar bent to zig-zag form and alternately engaged by the upper and lower chord" members and having an extended end portion engaged in the groove or recess of the upper chord member over the end portion thereof and in turn having a bearing plate welded to its lower face; the provision of a bar joist structure including upper and lower chords each of which is formed from a pair of angle section members arranged in back to-back relationship, the opposed faces of the members of each chord being spaced from one another, the web of the joist comprising a zigzag bar member of greater diameter than the spacing of the opposed flanges of the chord members, and the cooperating marginal edges of the opposed flanges of the chord members being bent outwardly to stiflen such flanges and to provide a groove or pocket for reception of the cooperat ing portions of the web; and the provision of a bar joist of the type described in which the opposed flanges of the chord members are not only spaced from one another but are complementarily curved to provide a sinuous nail receiving groove between them.

The above being among the objects of the present invention the same consists in certain novel features of construction and combinations of parts to be hereinafter described'with'reference to the accompanying drawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illustrates a suitable embodiment of the present invention and in which like numerals refer to like parts throughout the several diflferen't views,

Fig. l is a partially broken-side elevational view of a bar joist constructed in accordance with the present invention;

Fig. 2 is an enlarged transverse sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a still further enlarged transverse sectional view taken on the line 3-3 of Fig. l.

The bar joist shown in the drawing and constructed in accordance with the present invention includes upper and lower chords indicated generally at it and I2, respectively, and an interconnecting web indicated generally at M. In

the-particular construction shown the upper 1 chord it is of greater length than the lower chord i2, its ends projecting longitudinally beyond the corresponding ends of the lower chord i2 soas to adapt the joist for support from the upper chord.

l Broadly speaking the chords Ill and I! follow the teaching disclosed and claimed in United States Letters Patent to Buelow, et al. No. 1,900,541 and particularly to the form of the half stud disclosed therein. In other words each of the chords l0 and I2 is made up of a pair of angle sectioned members and the corresponding flanges of these members are arranged in backto-back but generally spaced relationship with respect to each other, and the surfaces of the remaining flanges are arranged in coplanar relationship. Those flanges which are arranged in back-to-back and spaced relationship are complementarily curved and the spacing between them is such as to provide a sinuous nail receiving slot or groove 20 between them.

The two angles l8 and II are rigidly secured together by means of boss-like projections 22 formed at intervals in one of the curved flanges and which bear against the curved flange of the other angle member to which they are suitably secured as by welding, riveting. or the like. The bosses 22 also serve to accurately space the curved flanges from one another so as to provide a nail receiving groove or recess 20 of uniform width throughout the length of the chord. The angle members are further rigidly spaced and secured together by welding to the web it as will hereinafter be described.

The use of the above described type of chords II and it permits the nailing of cooperating material directly to the upper and lower faces of the joist. Such material may obviously be flooring. lathe, sheet material of any desired type or description, or the like. For the purpose of illustration a section of wooden flooring 24 is illustrated in Figs. 1 and 2 as being applied to the upper surface of the upper chord shown in these figures, the flooring 24 being secured in place by means of nails 2 driven down through the flooring into the nail receiving grooves ll as illustrated in Fig. 2. As more fully described in the above identified Buelow et al. patent, this construction provides means whereby such material as the fiooring I may be readily nailed directly to the angle members II and II by the usual types of nails which will hold the material 24 to the angles with much greater security than is usually possible where the nails are driven through the material 24 and into woods commonly used in construction purposes.

The angle members It and II are preferably formed from sheet material and rolled or bent to angular shape and the gauge of the material from which they are formed may, of course, be sufficient to obtain the desired strength in the completed joist. In order to stiffen the chords Ill and it against distortion under load, it has been found preferable, in accordance with the present invention, to inwardly fiange the free marginal edges of the horizontally extendingfianges of the angle members I. and I. as best illustrated at I! in Fig. 3, this permitting the use of a lighter gauge stock in the angle members than would otherwise be possible.

To further stiffen the angle members it and I8 against distortion in a lateral direction as well as to provide a seat for the web ll therein, the free maginal edges of those fianges of the angles I 6 and I8 arranged in back-to-back relationship are outwardly curved or flanged as best illustrated at in Fig. 3 so as to form a preferably longitudinally continuous groove or pocket 32 between such marginal edges the cross-sectional curvature of which is approximately complemetary to the exterior curvature of the web I.

The web It may be made up. of one or more bar elements and arranged in zig-zag relation between the chords II and I2. Preferably the web It is made from a single continuous bar which may be of any desired cross-sectional configuration but for the purpose of simplicity is preferably round as shown and of a diameter substantially greater than the width of the nail receiving groove II so that the groove 32 will offer positive shoulders interiorly thereof for contact with the web ll. The bar from which the web It is formed is bent into zig-zag relationship illustrated in Fig. 1 with the bights of the loops preferably flattened oi! as at 34 to provide a horizontally extending surface of material length at the points where the web I4 is received in the pocket 32. The web I4 and the angles I. and II of each of the chords II and I! are preferab y suitably welded or otherwise secured together at their areas of contact, resistance welding having been found suitable for this purpose.

The zig-zag bar web I is preferably so constructed and arranged that the outermost run thereof at each end extends upwardly from the corresponding end of the lower chord outwardly toward but materially short of the corresponding end of the upper chord, and at the point where it meets the upper chord such end is bent horizontally into parallelism with such upper chord as at 36 and is received within the groove or pocket 32 at such end and is firmly welded therein. A bearing plate 38 which may be relatively heavy plate of metal of rectangular cross-sectional configuration is positioned with the plane of thickness in a horizontal relation below and in contact with each extended end I. and it is suitably and rigidly welded thereto as indicated at 40 in Fig. 3. Asillustrated in Fig. 1 the bearing plates 38 are preferably of a length greater than the corresponding ends II and the inner end of each plate is, therefore, bifurcated for reception of the last corresponding run of the web ll so as to bring the outer end of the hearing plates 30 fiush with the corresponding outer ends of the upper chord II as illustrated. Accordingly, it will be observed that with this construction the last or outermost runs of the web ll have their end portions interposed between the bearing plates and the corresponding end of the upper chord II which thus positively ties in the outer end of the lower chord to the corresponding end of the outer chord so as to positively transmit the load between the two chords at their ends.

From the foregoing it will be appreciated that because of the spacing of the angles I! and II to provide a nail receiving slot between them not only is it possible to directly nail flooring, lathing, or the like directly to the joist but the spacing of the angles and their rigid securement to one another stiffens the structure against lateral distortion. Furthermore, the provision of the groove or pocket for reception and securement of the web H provides in effect laterally projecting flanges which, together with the flanges 2! at the outer margin of the faces of the angle members it and II, materially enhances the strength of the structure against both lateral and vertical distortion. It will also be appreciated that this feature provides a bar joist of maximum strength for the amount of material employed in its construction, thus making the construction economical to use and that the construction as a whole, because of its simplicity, is economical to produce.

Formal changes may be made in the specific embodiment of the invention described without departing from the spirit or substance of the broad invention, the scope of which is commensurate with the appended claims.

What is claimed is:

i. A bar ioist comprising a pair of chord members and an interposed web member, each of said chord members comprising a pair of angle members arranged in back-to-back and generally spaced relationship, those flanges of said angle members arranged in back-to-back relationship being complementarily curved to form a sinuous nail receiving groove between them, the free marginal portions of said curved flanges of each chord being outwardly bent away from one another to form a groove extending longitudinally of said chord therebetween, and a web including a zig-zag bar member positioned with the consecutive bights thereof received alternately in the pockets of said chord members and secured therein.

2. In a bar joist, in combination, upper and lower chords and a web interconnecting the same, said chords each comprising a pair of angle members secured together in back-to-back and generally spaced relationship so as to aflord a fastener receiving groove between them, the free marginal edge portion of those flanges of said angle members in back-to-back relationship being outwardly bent with respect to each other to form a groove therebetween, a zig-zag bar web having its bights alternately received and secured in the groove of the upper and lower chords, an outermost run of said web extending upwardly from the lower of said chords and outwardly therefrom towards the corresponding end of the upper of said chords and having a longitudinally extending end portion received and welded in said groove in the upper of said chords, and a bearing member secured to said end portion.

3. In a bar joist, in combination, an upper chord and a lower chord each comprising a pair of angle members arranged in back-to-back rela- 1 tionship, the free marginal edge portions of said flanges arranged in back-to-back relationship being bent outwardly with respect to each other to provide a longitudinally extending groove, a zig-zag bar web member arranged between said chords with the bights thereof received within said grooves and secured thereto,said upperchord extending longitudinally beyond the corresponding ends of the lower of said chords, and the end runs of said web member extending from the corresponding end of said lower chord upwardly and outwardly towards the corresponding end of the upper of said chords and terminating in a longitudinally extended end portion received within the groove of said upper chord and secured thereto, a bearing plate at each end of said joist having a bifurcated end portion receiving the last run of said web at the corresponding end of said joist disposed below the corresponding said extended end portion of said last run and welded directly thereto. I

4. In a joist, in combination, upper and lower chords each comprising a pair of members arrangedin generally spaced back-to-back relationship so as to provide a fastener receiving groove between them, at least one member of each said pair being formed to provide a flange for the corresponding chord, the free marginal edge portions of said members extending outwardly away from each other to form pockets therebetween, and a web member extending between an spacing said chords, said web member comprising a bar bent to zig-zag formation with the bights thereof received and secured in said pockets.

5. A joist comprising upper and lower chords and a web interposed therebetween, said chords each comprising a pair of members arranged in generally spaced back-to-back relationship so as to provide a fastener receiving groove between them, at least one member of each said pair having a laterally extending flange, the marginal edge whereof is bent into angular relationship with respect thereto whereby to stiffen the corresponding chord against vertical distortion, the free marginal edge portions of said members being outwardly bent to form a longitudinally extending groove therebetween whereby to stiffen said flanges against lateral distortion and to provide web receiving pockets, and a bar web extending between said chords and received and secured in said pockets.

JULIUS A. CLAUSS.

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