US2994944A

US2994944A - Method of fabricating metal building frame truss units

Info

Publication number: US2994944A
Application number: US804277A
Authority: US
Inventors: Prudhon Clark
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-01-06
Filing date: 1959-04-06
Publication date: 1961-08-08
Anticipated expiration: 1978-08-08

Description

C. PRUDHON Aug. 8, 1961 METHOD OF FABRICATING METAL BUILDING FRAME TRUSS UNITS 5 Sheets-Sheet 1 Original Filed Jan. 6, 1956 Mark Fwd/7022 8, 1961 c. PRUDHON 2,994,944

METHOD OF FABRICATING METAL BUILDING FRAME TRUSS UNITS Original Filed Jan. 6, 1956 3 Sheets-Sheet 2 Hark Frz/dlmn C. PRUDHON Aug. 8, 1961 METHOD OF FABRICATING METAL BUILDING FRAME TRUSS UNITS Original Filed Jan 6, 1956 5 Sheets-Sheet 3 [/ir/r Prudhan United States Patent 2,994,944 METHOD OF FABRICATING METAL BUILDING FRAME TRUSS UNITS Clark Prudhon, Pruden Products Co., Evansville, Wis. Original application Jan. 6, 1956, Ser. No. 557,796, now Patent No. 2,904,139, dated Sept. 15, 1959. Divided and this application Apr. 6, 1959, Ser. No. 804,277

2 Claims. (Cl. 29155) This invention relates to metal frames for buildings such as warehouses and sheds, and refers more particularly to an improved method of fabricating building frame trusses comprising spaced apart chords and transverse ties welded thereto and transversely connecting them.

More specifically this invention relates to a method for facilitating the fabrication, by welding, of trusses whose chords comprise complementary L-section chord members which are disposed back to back and are welded to opposite sides of the end portions of the tie members that transversely connect the chords.

While the method of this invention may be advantageously employed for the fabrication, by welding, of such trusses of more general shapes, it is particularly suited for facilitating fabrication of composite truss units comprising a column-like wall supporting truss section and a rafter-like roof supporting truss section joined at an obtuse angle thereto. A truss unit of this latter type forms the basis of my copending application, Serial No. 557,796, filed January 6, 1956, now Patent No. 2,904,139, of which this application is a division.

It is the object of this invention to provide a method of fabricating building frame trusses and truss units of the character described, from L-section members welded together in such a way as to obviate the necessity for moving the partially finished truss or unit at any stage during its fabrication, prior to its completion, and without the need for making overhead welds or welds in locations which are difficult to get at.

Another object of this invention resides in the provision of a method by which a building frame truss or truss unit of the character described may be inexpensively manufactured without the necessity for removing it from a fixture in which it may be held for Welding until it is completely finished.

With the above and other objects in view, which will appear as the description proceeds, this invention resides in the novel method substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the method for practicing this invention according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIGURE 1 is a perspective view of a building with portions of its walls and roof cut away to illustrate the manner in which they are suported by truss unit frames produced in accordance with this invention;

FIGURE 2 is a side elevational view of one of the building frame truss units per se;

FIGURE 3 is a fragmentary perspective view of an end portion of a truss section forming part of one complete truss unit;

FIGURE 4 is a fragmentary perspective view of an end portion of another truss section of which the truss unit is comprised;

FIGURE 5 is a fragmentary perspective view showing a portion of a fixture in which trusses or truss units may be fabricated by the method of this invention, with Patented Aug. 8, 1961 ICC certain of the chord members in position to be placed in the fixture for the first welding step;

FIGURE 6 is a fragmentary perspective View corresponding to FIGURE 5 but showing a portion of the truss unit at an intermediate stage of its fabrication; and

FIGURE 7 is a view similar to FIGURE 6 but show ing a portion of the truss unit in substantially finished form and removed from the fixture.

Referring now more particularly to the accompanying drawings in which like numerals designate like parts throughout the several views, the numeral 5 designates generally a building, such as a garage, shed or warehouse, incorporating building frame truss units fabricated in accordance with this invention. 7

The truss unit per se, which forms the subject of my copending application Serial No. 557,796, filed January 6, 6, now Patent No. 2,904,139, granted September 15, 1959, generally comprises an upright column portion 9 and a straght roof supporting rafter portion 10 connected to the upper end of the column portion and defining an obtuse angle therewith. Both the column and rafter portions 9 and 10 comprise truss sections having elongated chords 7 connected and braced by ties 8.

As illustrated in FIGURE 1, a building frame comprises a number of these truss units extending across the building and spaced along its length, together with lengthwise extending girth strips 11 and purlins 12. To facilitate transportion of the frame members, each has its rafter portion 10 constructed in two sections, namely an inner section 13 adjacent to and permanently joined to the top of the column portion 9, and an outer section 14 detachably connected to the inner section 13. Preferably the length of the outer section 14 is about twice that of the inner section 13 which is integral with the column portion 9, so that the outer rafter section 14 will be of about the same size as the remainder of the truss unit. The rafter sections 13 and 14 may be fastened together in endwise abutting relationship by means of tie plates 15 on their chords welded to one of the rafter sections and bolted to their adjoining rafter sections.

It will be observed that the frame units extend across the building in pairs, the units at opposite sides of the roof centerline being identical with one another, and the outer ends of the rafter sections 10 being joined to one another at the roof centerline. For this purpose an upper tie plate 16 at the top of each unit provides for its connection with a similar tie plate on a mating unit at the opposite side of the building, as by means of a bolt or similar fastener engaged in aligning holes 17 in said tie plates.

The lower end of the column portion of each unit is provided with a base plate 18 by which the unit may be secured to a suitable footing 19, as by means of studs projecting upward from the footing through holes 20 in the base plate. It will be seen that two truss units (each consisting of a column portion and connected inner and outer rafter sections) may be readily fastened together while lying flat on the ground, by means of a bolt through their flatwise overlying tie plates 16, and may be readily erected and secured to a footing.

Girth clips 21 on the outer chords of the column portions and purlin clips 22 on the upper chords of the rafter portions provide for attachment of girth strips and purlins, respectively, which may be ordinary 2 X 6 lumber or the like. Both the girth clips and the purlin clips comprise short channel shaped elements having their webs welded or otherwise secured to the chords with their flanges outermost. Nail holes 23 in the flanges facilitate attachment of the framing lumber. In the purlin clips 22 one flange of the channel is relatively short to clear a nail driven through the purlin from the other flange.

With the purlins and girth strips in place, any suitable 3 sheet siding 24 and roofing 25 may be fastened thereto to finish the building.

The completed truss unit is shown as fabricated entirely from L-section members, except for attachment fittings (clips, tie plates, etc.). Moreover, each of the truss unit sections has inner and outer chords, each of which chords comprises complementary L-section chord members 27 disposed back to back and secured to opposite sides of the tie members, at the end portions of the latter. Thus, the tie members are disposed substantially on the median plane of the truss section, so that imposition of a load on the unit will not set up unevenly distributed strains therein which might twist or warp it, as would be the case if the ties were all disposed to one side or the other of the median plane.

The novel method of fabricating trusses and/ or truss units is disclosed in FIGURES 5 through 7, which fragmentarily show a composite truss unit comprising a column section 9 and an inner rafter section 13 in various stages of manufacture. A relatively simple channel-like fixture 26 may be used in fabricating such a truss unit. The fixture is disposed substantially horizontally and has upstanding legs or flanges 28 for supporting those chord members 27 which are to be secured to one side of the ties in relative positions corresponding to those of the chords on the finished unit. This first set of chord members is held in the fixture with one leg 29 of each chord member disposed substantially coplanar (preferably substantially horizontal) with one of the legs of the other chord members, and with the other legs 30 of the chord members projecting in the same direction (e.g. downwardly) therefrom, to lie flatwise against the inner surfaces of the flanges 28, and resting edgewise upon the bottom of the fixture. These chord members may be held in said positions by means of tabs 31 struck up from the base or bottom of the fixture, or in other words, tabs 31 cooperate with the flanges 28 to confine the legs 30 of the chord members in a vertical position, and the legs or backs 29 of the chord members in a horizontal position.

The column and inner rafter sections of the unit are thus defined by separate chord members endwise abutting one another at an obtuse angle, and are butt welded together at their junctions as at 33, with the chord members of each of the column and inner rafter sections converging away from said junctions.

From positions above the fixture and the chord members therein, shorter tie members 8 are next welded to the first set of chord members 27. The tie members are held in the fixture by means of clip-like fingers 35 on the bottom thereof, with each tie member disposed with one of its legs 36 in a plane spaced above but substantially parallel to the plane containing the backs or legs 2-9 of the chord forming members and the other legs 37 of each tie member extending vertically downwardly toward and seating upon the backs 29 of the chord member. The downwardly projecting legs 37 of the several tie members are edgewise welded to the horizontal legs of the chord members therebeneath, at each end of each tie member, so that every tie extends between and is bonded to both pairs of the inner and outer chord members 27.

Since the tie member 38 which connects across the junctions 33 of the chord members is subjected to very large compressive loads, it is preferably fashioned from a pair of L-section members disposed adjacent to one another with their legs projecting in opposite directions and 'welded to form a hollow square section. To provide further rigidity and reinforcement at the corner defining the junction of the wall column and rafter portions, one tie member 39 extends straight and unbroken across the inner corner, being fastened at its ends to the outer chord members and at its middle'to the apex portions of the inner chord members.

Fabrication of the truss unit is then completed in the fixture by welding a second set of chord members 41 to the ties, again from locations above the fixture and the members therein, with the chord members of the second set disposed in complementary relation to those of the first set. The chord members 41 comprising the second set thereof are arranged back to back with those of the first set, or in other words with each chord of the finished unit comprised of two L-section members, each having one of its legs parallel to and spaced from a leg of the other, with the other legs of the two complementary chord members coplanar and extending in opposite directions from their parallel legs or backs, and with the ties interposed between and welded to the parallel legs or backs of both pairs of complementary chord members.

Because of the disposition of the ties, the second set of chord members 41 may be welded directly to their horizontal legs without necessity for turning the fixture or removing the unit from the fixture and without the necessity for overhead or other diflicult welding op erations.

The tie plates, foot plate, and purlin and girth clips may of course then be welded to the structure while it is still in the fixture. The upper tie plate 16 should be disposed off-center, with one face thereof lying on the median plane of the structure, so that when the tie plate of another unit is secured to it the two units will have coinciding median planes and will not have to be warped or twisted during erection to provide a properly squared up structure. The correct position of the upper tie plate 16 can, of course, be obtained with a suitable spacer block 43.

The outer rafter-like truss sections are fabricated in similar fashion, in a fixture having locating and supporting flanges for its complementary pairs of chord members, which flanges are entirely straight but converge toward one end of the fixture.

From the foregoing description taken together with the accompanying drawings it will be apparent that this invention provides a method for fabricating building frame truss units having elongated chords comprising pairs of complementary chord members and ties connected between them, all formed from L-section material, wherein the units may be fabricated in fixtures to assure uniformity, without the necessity for removing them from the fixtures at any time during fabrication and without entailing overhead or other difficult welding opera tions. It willalso be appreciated that the method of this invention may be practiced to advantage regardless of whether the members, and particularly the chord members, have an L-section or some other cross sectional configuration, such as a channel shape, as long as the chords are comprised of complementary members arranged back to back and secured to opposite sides of the ties.

What is claimed as my invention is:

1. In the method of making a building frame truss unit having elongated spaced apart chords connected by ties, which method involves the use of a fixture for locating and holding the chords in their proper positions during fabrication, the characterizing steps of: supporting the fixture in a substantially horizontal position; supporting a pair of elongated L-section chord members in the fixture in relative horizontal positions corresponding to those of the chords of the finished truss, but with one leg of one chord member substantially in the plane of one leg of the other chord member and with the other legs of the chord members projecting downwardly, to one side of said plane; welding a plurality of shorter L-section tie members to said chord members, in positions bridging the same and with the end portions of one leg of each of said tie members seating edgewise upon the coplanar legs of said chord members, and with the other legs. of said tie members substantially disposed in a common second plane parallel to but spaced above said first designated plane; securing other elongated L-section chord members to the end portions of said tie members, in positions complementary to said first designated chord members, by welding portions of one leg of each of said other chord members flatwise upon the end portions of the coplanar legs of said tie members, and so that the other leg of each of said other chord members extends upwardly and lies in the plane of the downwardly projecting leg of its complementary chord member; and performing all of said welding operations from positions above the fixture and the members placed therein, while the fixture remains in said substantially horizontal position.

2. In the method of making a building frame truss unit having elongated spaced apart chords connected by ties, which method involves the use of a fixture for locating and holding the chords in their proper positions during fabrication, the characterizing steps of: supporting the fixture at a readily accessible location where welding operations can be easily performed therein without involving overhead welding techniques; supporting two chord forming elements that are to have ties secured to one side thereof, in the fixture with said two chord forming elements located in the same general plane and in relative positions corresponding to those of the chords of the finished truss; from said side, welding said ties to said side of the two chord forming elements to bridge the same; thereafter welding the remaining chord forming elements to the ties at the side of the latter remote from said two chord forming elements; and performing all of said welding operations from positions opposite said side of the two chord forming elements while the fixture remains in said readily accessible location so that said welding operations can be performed entirely from one side of the fixture to obviate the need for turning of the fixture or removal of any of the partially fabricated truss unit components from the fixture during welding.

References Cited in the file of this patent UNITED STATES PATENTS 1,549,251 Geyer Aug. 11, 1925 1,618,536 Junkers Feb. 22, 1927 1,776,467 Frandsen Sept. 23, 1930 2,365,175 Crawford Dec. 19, 1944