US2151861A - Girder - Google Patents

Description

March28, 1939. A, M, MCLELLAN 2,151,861

I GIRDER Filed Sept. 24, 1937 Patented Mar. 28, 1939 UNITED STATES GIRDER- Arthur M. McLellan, Los Angeles, (fsalif t, assignor to McLellan Steel Development Corporation, a.

corporation of Nevada Application September 24, 1937, seriaiNd. 165,438

17 Claims.

My invention relates to building construction of the type set forth in- Patent No. 2,053,487 is-' sued to me September 8; 1936, and pertains more particularly to an article of manufacture inthe form of a girder which when assembled in multiples and interconnected according to the presentinvention, or according to the teachings ofsaid patent, will provide all the advantages peculiar to the aforesaid constructionas well as attaining the other objects and advantages apparenthereinafter.

The present invention as well as my prior inventions in this form of construction aredirected to the provision of joints, preferably Welded joists, arranged to provide greater strength and fixity than is possible with ordinary welds or joints" and to comply with almost universal ordinances to the efi'ec't that the weld shall not be depended upon to carry the load directly. Accordingly it is an object of this invention to interconnect the various members with an improved weld or'joint while reducing the number of welds or joints, lowering the manufacturing cost as" a whole, providing; higher standardization of fewer manufactured parts, and otherwise contributing to the provision of strong and rigid light-weight frames in homogeneous structure's.

Apart from other features of construction it is an object of the invention to provide a manufactured girder, column, truss, or the like; as a complete article of manufacture either in a given length or in a plurality'of'shcrter lengthsadapted' to be spliced by any suitablemeans.

Another and equally important object of this invention is to provide a girder of the class described which while meeting the foregoing objects provides for readily assembling several girders to'forln a single wall section or the like by the act of welding tie rods thereto of any 40 suitable form; the girder providing shoulders within the spirit of this invention and the said patent whereby the weld is readily accomplished wh-il'e conforming to strict building ordinances.

' While it h'asbeen stated hereinb'efo're that to 45 relieve the welded area from direct load is an object of the invention, this invention goes even further in seeking to provide, and in providing, that the'parts which areto-be subjected to maximum load are not subjected to sudden tempera ture'" changes during Welding, or to sudden molecular re-arrangement' suchashasbeen found to" give: trouble in other welded structures.-

In the aforesaidp'atentit has been taught-that large areas of frame could be assembled and' transported to the site and there spliced by any" well known means, and this invention is directed as well to shop assembly of a plurality of girders and ties to provide large sections of greater fixity and precision thancan be realized at the site. The use or round stock is preferred and it is an object of the" invention to so lower the cost of construction and assembly that round stock, which'is more readily available than any other cross section of steel, may become the more economical and generally used material of which to coi-istril ctany frame whatsoever. In my c'o-pending application Serial Number 135,118; I have described a method whereby water prooffelt, paper, or the like may be economically applied together with a suitable form of are so that certain structural elements of the frame combine to fol-ni stiffeners without employing the expensive re-enforcements usually required to be embodied in re-enforced plaster bases. It is an object of this invention to provide such r'e-enforcing'members as a part of the new frame sections herein disclosed, and, without added cost.

In my co-pending application Serial Number 134,782, I have shown and described means and methods for encasing my frames in cement to provide acomplete structure comprising monolithic walls and integral interconnecting webs. It is an object of this present invention to provide at no additional cost; astructure which is char acterized by niches opening" at each face and in each of which maybe disposed alight hollow core so that when cement is applied all members will be encased in aprotective" monolith.

However, the present invention is directed to a steelframe which is complete in itself and does not require the addition of cement for structural strength Also" this invention is particularly directed to the provision of joints which do not tend to deteriorate asdo common welded joints. Prior welding methods give rise to" sudden temperature changes and to rearrangement of the molecules and it is an object ofthis invention to provide a weld or joint which is more ideal.

The aforesaid patent shows a plurality of superimposed load-supporting shoulders which have p-roven to be of inestimable value in fabricated steel structures of this type and which I desire to obtain in the present structure altho this invention seeks to obtain the same results while reducing the cost and number of such shoulders. It is an object of the invention to provide all of the benefits peculiar to the structure set forthin' the said patent but at greatly reduced cost of manufacture; I

Accordingly the invention provides that each main cord member is provided with spaced, but otherwise individual substantially integral annular enlargements or shoulders. All other members of the structure connecting with the chord members shall connect at corresponding shoulders so that in effect one shoulder becomes a corresponding substantially integral shoulder for that end of each member where it connects with the corresponding chord.

Thereby the spirit of the said patent is retained in the structures peculiar to this invention while the number of shoulders is reduced.v

Also the invention reduces the number of welds and the number of short links, and permits of the use of long rods to interconnect several girders, trusses, or the like.

Another and important object of this invention is to provide for the fabrication of large sections and altho various fastening means and methods may be employed the invention provides for first manufacturing girders in mass production, then placing several girders in spaced parallel relation-- ship, and then interconnecting them with long rods; the construction of the girders being such that high speed fusion welding may be employed to securely join the rods and girders to form a large area light weight section for walls, roof, floor or the like, while small building frames may be completely erected at the shop.

Other objects and advantages will appear hereinafter, and particularly the structural and economic advantages accruing from the methods and means by which I provide, at single points, the effect of a multiplicity of shoulders (one for each connecting member) while preventing welded areas from being directly subject to the loads.

I have illustrated my invention by the accompanying drawing in which I show only one practical embodiment of my invention. In the said drawing:

Figure 1 is a fragmentary vertical section of a frame which is constructed according to this invention; this view showing the girder in side elevation.

Figure 2 is a section of such frame seen on a horizontal plane and clearly showing the said shoulders and the manner in which all other members connect therewith.

Figure 3 is a larger scale fragmentary perspective of the joint formed by the shoulder and connecting parts.

Figure 4 is a cross section thereof.

The girder l is shown as comprising two spaced parallel chord members 1, I, here shown as being common round stock and of a diameter according to requirements. The member I may be a vertical girder or it may be a truss, horizontal, floor joist, inclined roof rafter, or the like, or, according to the teachings of the said patent the member I may be continuous from the floor of a building up thru one side wall and then over the roof and then down over the other side wall and back to the floor. However this invention is directed more particularly to the member I and to the means by which many such members are interconnected. Therefore no particular building or wall section is illustrated herein.

Between the two spaced chords 1 and I respectively I provide a pair of continuous zig-zag or latticing members or braces 8, 8, which as nearly as possible are disposed in the same plane with each other and are thus arranged in lazytong formation to provide interconnecting X- braces. Specifically, one zig-zag member extends from a point on one chord member diag- Onally to a higher point on the opposite member then back to a still higher elevation on the first named chord member, while the second zigzag member contacts with the chord members at points directly opposite the points where the first named zig-zag contacts. These members are easily manufactured from long lengths of common round stock by being fed in groups to any suitable machine (not shown) which bends them accordingly.

In keeping with the invention, and by reason of the manner in which the girders are incorporated in a complete structure, these brace members are designed for both tension and compression. Where these members cross each other repeatedly as at 10, they are preferably welded to greatly reduce the slenderizing ratio and to peculiarly fit them for the loads to which they are subject. This welding may be done by fusion welding or any other suitable form of fastening.

The two zig-zags, so interconnected will under imposed axial load tend to distort as does a lazy-tong. However to resist this action under axial tension and under axial compression as well, these members, at the most widely spaced points are held together by means about to be described, and which means also serve to additionally tie the chord members together. It will be seen that the zig-zags abut the opposed surfaces of the chord members and must be held thereto, altho it is an object of this invention to avoid the old practice of welding latticing members direct to the chord members of a girder, truss, or the like. To do this would throw loads directly on the welds or joints and would also subject the main chord members at several closely spaced points to sudden temperature changes and to a general weakening incident upon the use of old welding methods.

Accordingly I provide the links H, II, each of which is short enough and rigid enough to serve under either tension or compression. Each link is disposed horizontally where corresponding opposite parts of the two ,zig-zags abut the chord members. Each link has each end suitably looped; as at l2, l2, and each loop encompasses both the corresponding part of the corresponding chordmember as well as the abutting part of the braces. Usually the cross section of the brace is of much lesser diameter than the cross section of the chord member with the result that the loop takes on a pyriform characteristic. In any event the loop closely contacts the chord member thruout at least one-half of the circumference of the chord member and is forced together at its inner or smaller end to closely contact both sides of the encompassed part of the brace. Thus the loop contacts the corresponding part of the brace at two almost directly opposed points and the free end of the loop, as at I2 is brought practically into contact with the straight part of the link [2.

There are divers methods for forming this loop all within the realm of common mechanical skill altho it is most important that this loop be so formed as to give certain final results, hereinafter set forth. Also whilethere are various methods and means known to me, and within the skill of others, for securing the loop, it is a particularly salent feature of this invention that the loop is securely joined to the correenamel sponding part of the brace and also to the chord member without the chord being weakened or being subjectedto weldingoperations. I I

Preferably this is done by passing a fusionwelding current along the line I 4-H of Figure 4 so that both sides. of the loop arewelded-to the adjacent parts of the brace or zig-zag member. The results of this general method of attaching all parts, and particularly'the-welding method, are numerous. First. it provides for completely assembling a girder before welding provided of course that-machinery is used to form theloops and to temporarily lock the parts together before welding; In fact it is best that the loop be partially formed and the girder parts be-accurately assembled and held before welding is begun. "In fact, in some-cases closure of the link by common methods will provide a suitably complete girder without welding, while in other cases arc welding or mechanical fastening means may be employed. llfthe loop is notcomple'ted initially the fusion form of welding permits of passing current thru opposite parts of a partially formed loop to vheat same while pressure is then applied towclose the loop whereupon the real welding takes place. .In either form of welding it is found that the main chord members are not unduly heated orweakened; the :parts are not actually'welded to the main chord members; and .the weldsare not directly subject to load. However it isfound thatwhereas the loop is heated its subsequent cooling causes it to shrink around the main chord member and this results inthe loop providing the required load supporting shoulder, on the chord member asa substantially .integral part thereof. At the same time that this cooling and shrinking takes place the adjacent parts ofthe zig-zags are forced into morepositive abutment with the corresponding parts of the chord members sothat both compression and tension to which the diagonal extents of the braces are subjected is well resisted, compression being directly against the chord and the tension being taken thru the loop.

This joint, and particularly this method of welding, has the efiect of combining two ends of diagonal bracing members and two portions of the loop, into a single member which in effect will result in all adjacent parts of the braces and links being provided each with a shoulder integral with and common to all and which shoulder by reason of the shrinkage fit has become a substantially integral part of the chord member. Thus this invention provides the many advantages peculiar to the first named patent and at reduced cost of manufacture.

In actual manufacturing practice I prefer to place the two rods in spaced parallel relationship and to then place the zig-zag member in place between them. Then while the rods and zigzag members are held in this position the links are successively secured by bending and welding each end of each link into the position shown.

While this may be done in any simple jig or fixsure (not shown) mass production is had by feeding the two rods or chord members, together with the zig-zags, thru an automatic machine (not shown) which first secures one link in position and then moves on to the next position at which a link is to be secured, and then after securing this link moves on to the third, and so on, until a complete girder is made,

The girder now represents the ideal combination of light weight, low cost, resistance to decomposition and fatigue, and universal application in structures. It will be apparent now that two such girders joined together by suitable links, as taught by the aforesaid patent, will provide .a box'column or thelike while several placed in with any suitable jig or fixture (not shown) in the'manufacturing plant. Then common round stock rods in long lengths, as indicatedat I5, i5, etc.,- are placed normal to the faces of the girders and in contact with thecorresponding shoulders. Then a fusion-welding current'ispassed along the line. l6l6 thru each shoulder and the abutting part of the rod 15. In this way the girders are quickly incorporated in a light Weight wall section of great fixity which may be made in large sizes before being transported to the site.

I am aware that in many cases additional bracing or diagonal interlacing may be required to further connect the girders and it is apparent that'these also may be rested upon and welded to the shoulders which this invention provides; allaccording to the aforesaid patent. Also this invention or the structure which it provides may be incorporated with various features shown by the aforesaid co-pending applications. This application is acontinuation in part of my applications Serial Number 134,782, filed April 3, 1937, and Serial Number 135,118, filed April 5, 1937.

The rods shown in this disclosure provide for fastening building paper or felt, masonry or the like to the surfaces of the structureand these rods also divide the structure into a plurality of cells or niches in which hollow cores or the like may be inserted to retain light weight and to conserve on the material where cement or the like is used to enclose all parts of the frame.

While this invention is peculiarly suited to fusion welding methods, arc welding or mechanical fastening means may be employed in place of fusion welding. While large wall sections, fabricated at the factory may be spliced at the site by welding, it is to be understood that the invention is not limited to welding and the said large sections may be spliced by any well known means such as fish plates, shrunk sleeves, splines or the like, all within the realm of mechanical skill and my invention is not limited by the drawing or foregoing specification and is defined only by the appended claims.

I claim:

1. In a girder, a pair of spaced parallel rods, transverse links connecting said rods, each link comprising a rod having each end bent into a loop with each loop encompassing the corresponding part of the corresponding rod, and diagonal braces connecting said rods and having each end extended thru and secured by the corresponding loop.

2. The girder as in claim 1 and in which each loop is welded directly to the encompassed part of the corresponding brace.

3. The girder as in claim 1 and in which each loop is welded directly to the encompassed part of the corresponding brace-end while being a shrunk fit aroundthe corresponding rod.

4. The girder as in claim 1 and in which a plurality of said-braces are provided in the form of a continuous zig-zag member passing thru successive corresponding loops.

5. The girder as in claim 1 and in which a plurality of said braces are provided in the form of a continuous zig-zag member passing thru successive corresponding loops; each loop being welded to the corresponding part of the zig-zag.

6. The girder as in claim 1 and in which a plurality of said braces are provided in the form of a continuous'zig-zag member passing thru corresponding loops; said loops being shrinkage fits on the corresponding rods'and said loops being directly welded to encompassed portions of said zig-zag members.

7. In a building wall, a plurality of spaced parallel girders each provided at each face with spaced parallel shoulders, and means interconnecting said girders comprising straight rods secured to corresponding shoulders of several successive girders; each girder comprising a pair of spaced parallel chords, transverse links each comprising a rod bent to form a loop at each end, each loop encompassing the corresponding of the pair of parallel chords, and diagonal braces having each end extended thru and secured by the'corresponding loop.

8. The building wall as in claim '7 and in which each loop is welded directly to the encompased part of the brace.

9. The building wall as in claim '7 and in which each loop is welded directly to the encompassed part of the brace while each loop is a shrunk fit on the corresponding rod.

10. The building wallas in claim;'? and in which each brace is integral with adjacent braces.

11. Thebuilding wall asin claim 7 and in which several braces are provided in the form of a continuous zig-zag member passing thru and welded thereat to successive loops.

12. The building wall as in claim 7 and in which continuous zig-zag members provide several of the braces and pass thru successive loops; said zig-zag members being thereat welded directly to the corresponding loops and .said loops being shrunk fits on corresponding-rods.

13. In a building girder, a plurality of spaced parallel links each having each end bent to form a loop at each end, a pair of zig-zag members each crossing the other at points intermediate of said links and passing first thru a loop at one end of one link and then thru the loop at the other end of the next adjacent link so that said links hold the two zig-zag members against distortion under axially applied working loads, and a pair of main chord members each passing successively thru the loops of the corresponding ends of said links.

14. The girder as in claim 13 each loop being a shrunk fit around the corresponding rod and the corresponding part of the zig-zag members.

15. The girder as in claim 13 and in which each loop is welded directly to the corresponding encompassed zig-zag part.

16. The girder as in claim 13 and in which each zig-zag member is welded to the other zigzag member at each point where they cross;

17. The hereindescribed method for assembling a girder consisting in: placing two rods in spaced parallel relationship, placing a zig-zag member between said rods to successively abut both rods, connecting a' link to each rod at each point opposite the points where the zig-zag member abuts, and then looping the other end of each link jointly around the corresponding part of the corresponding rod and the corresponding part of the zig-zag member to there hold the link firmly secured to the corresponding rod and to hold the corresponding part of the zig-zag in positive abutment therewith.

ARTHUR M. McLELLAN.

Images