US3104454A - Method of making structural members - Google Patents

Description

Sept. 24, 1963 H. E. HANDLEY ETAL 3,104,454

METHOD OF MAKING STRUCTURAL MEMBERS Filed Sept. 28, 1959 4 Sheets-Sheet l T to 0 220 0 o o o 0 o o i INVENTOR6 7 dr'0/d 15 f/andlqy Aobem L, M/kz'zman Leo J Spar/(fa @MQWJ ATTORNEY Se t. 24, 1963 H. HANDLEY ETAL 3,104,454

METHOD OF MAKING STRUCTURAL MEMBERS Filed Sept. 28, 1959 4 Sheets-Sheet 2 INVENTORS Gad/WM ATTORNEY p 1963 H. E. HANDLEY ETAL 3,104,454

METHOD OF MAKING STRUCTURAL MEMBERS Filed Sept. 28, 1959 4 Sheets-Sheet 5 I 40 I r fi I l l Zea J. Spa/"161a BY fl n ATTORNEY p 1963 H. E. HANDLEY ETAL 3,104,454

METHOD OF MAKING STRUCTURAL MEMBERS I Filed Sept. 28, 1959 4 Sheets-Sheet 4 co J Gparkl'a ATTORNEY United States Patent Oilfice 3,104,454 Patented Sept. 24, 1963 METHOD OF MAKING STRUCTURAL MEMBERS Harold E. Handley, Robert L. Whitman, and Leo J.

Sparkia, Jackson, Mich assignors, by mesne assignments, to McGraw-Edison Company, a corporation of Delaware Filed Sept. 28, 1959, Ser. No. 842,825 Claims. (Cl. 29-155) The present invention relates to improvements in structural members and methods of making the same and particularly to structural members which are assembled from separately fabricated components.

Fabricated metallic structural members such as I-beams, box beams, triangular beams, trusses, columns and the like have been generally fabricated from steel components welded, riveted or bolted together. Steel has been used in lieu of the non-ferrous metals because of the more favorable cost of steel, as compared with such nonferrous metals as aluminum and magnesium and their alloys. This difference in cost has more than offset the savings in maintenance, installation and transportation due to lightness and higher resistance to corrosion of the non-ferrous metals.

While the principles of the invention have application to structural members fabricated from all types of metals and plastics, the development of this invention has direct-ly resulted from eiforts to provide structural mem bers of aluminum alloy having cost characteristics which compare favorably with structural members of galvanized steel of standard shapes and designs.

Aluminum structural members have been widely used for many years where the need for structural lightness has more than offset the higher cost as compared to steel. Using standard rolled or extruded shapes, it has been found that aluminum alloy structural members having the same strength as a similar one fabricated from galvanized steel has cost so much more than galvanized steel that the savings in maintenance, transportation and installation inherent in aluminum were more than absorbed. This unfavorable cost comparison between aluminum and galvanized steel is greatest in aluminum structural members in which the components are welded together because of the loss of strength experienced in the.

heat affected area at the welded joints between the chords and the lacing.

The improvements of the present invent-ion in the cross-section of the components of the structural member has provided a high strength to weight ratio while the improved mechanical joint between the chord angles and the lacing has provided optimum performance in the joints and develops the full strength of the chords and lacing of the structural member. In addition to the elimination of heat affected areas resulting from welding, the improved mechanical joint of the present invention provides a further cost saving in that the structural members may be assembled by unskilled persons.

Thus, an object of the invention is to provide a method of making an improved structural member in which a greatly improved strength to weight ratio has been obtained which permits relatively high cost material, such as an aluminum alloy, to be economically used-in the fabrication of structural members.

Another object is to provide a method of making structural members in which the components of the members are attached by mechanical joints between telescop ing'portions of the components; the joints being characterized by the extrusion of port-ions of certain components into intimate shear relationship with certain other components to interlock the components into a functionally unitary structure.

A further object of the invention is to provide a method of making an improved structural member of assembled chord and lacing components in which a mechanical joint is provided which is substantially localized at the intersection of the longitudinal axes of the compression and tension lacing structures within the chords.

A still further object of the invention is to provide a method of making a structural member and method of making the same fabricated from individual chord and lacing components and having telescoping portions in which an adhesive having lubricating qualities at the time of assembly is employed to assist in telescoping the components into their proper relationship and to thereafter assist in the establishment of the joint between the components.

Another object of the invent-ion is to provide a method of making a mechanical joint between the chord and lacing components of a structural member in which the components interlock in intimate shear relation in planes at to each other.

Another object is to provide an improved chord having an outer bearing surface defined by reinforcing edge portions with an accompanying improved distribution of the loading of the forces upon the chord.

A still further object of the invention is to provide a mechanical joint between the chord angle and lacing of a structural member which will develop the full strength of the chord angle and lacing.

These and other objects and advantages will more iully appear from the following specifications and claims:

- In the drawings wherein the principles of the invention are illustrated as applied to several diiferent structural forms,

FIG. 1 is a fragmentary side-elevational view of a box beam,

FIG. 2 is a cross-sectional view of FIG. 1 taken on line 11-11,

FIG. 3 is a view similar to FIG. 2 of another formof box beam,

FIG. 4 is a cross-sectional view taken of an I-beam,

FIG. 5 is a cross-sectional view of a beam having U-section chords,

FIG. 6 is a side-elevational view of an extruded lacing in straight length form,

FIG. 7 is a view of the lacing of FIG. '6 tormed to provide an open work lacing between spaced chords of a structural member,

FIG. 8 is a cross-sectional view of the lacing taken on VIII-VIII of FIG. 6,

FIGS. 9, 10 and '12 show enlarged fragmentary sections of the formed lacing and illustrates the preparation of the same for use in structural members,

FIG. 11 is a sectional view taken on'line )GXI of FIG. 10,

FIG. 13 is a sectional view taken on line XIII-XIII of FIG. 12,

FIG. 14 is a view of FIG. 13 as shown firom below,

FIG. 15 is an enlarged fragmentary side-elevational view of the joint between the chord and lacing,

FIG. 16 is a cross-sectional view taken on line XVI XVI of FIG. 15,

FIG. 17 is a cross-sectional view taken on line XVII XVII of FIG. 15,

FIGS. 18, 19 and 20 correspond to FIGS. 10, 12 and 14 and show preparation of the lacing for a modified form of staking,

FIGS. 21, 22 and 23 correspond to FIGS. 15, 16 and 17 and illustrate the modified form of staking in the chord and lacing assembly.

The invention has application to all forms of structural members in which two or more chords are connected with a lacing member. When the lacing is angularly formed, the lacing connection between the chords is of open work construction while a solid lacing results from the use of a straight lacing section between a pair of chords.

' Preferably the chord and lacing sections are both extruded in fabrication. Where the structural member is to receive bolts or other fastening structures, the chords after extrusion :are perforated, the holes being preferably formed with a head with a minimum waste of material.

The chord and lacing sections are assembled by relative movement between telescoping male and female portions, after locating the chord and lacing in their desired relative position, the joints between the chord and lacing sections are then established of :a character that will develop the full strength of the chord and lacing sections in the composite structural member. This may be accomplished by a staking operation alone, or assisted by the presence of an abrasive, or an adhesive, or a combination of both. When the chord and lacing are of materials which tend to resist telescoping association of the components, such as aluminum and aluminum alloys, at lubricant may be used at the time of assembly. Prefeuably, the lubricant should thereafter develop abrasive or adhesive properties or both. In practice, epoxy resin has been used with excellent results.

As illustrated in FIGS. 1 and 2, a box beam is shown comprising four similar chord angles 19 connected by four similar continuous angular lacings 12. In FIG. 3 is shown a modified box beam having four similar chord angles 16, two similar continuous angular lacings 12 and two similar straight section lacings 14. The lacings 12 of FIG. 2 provide a beam with open work form on all four sides while the combination of the lacings 12 and 14 of FIG. 3

provide a beam which is of open work form on two sides and solid form, except for the bolt holes, on the remaining two sides.

An I-beam is shown in FIG. 4 in which the chords 16 are spaced and connected by a continuous angular lacing 12. It will be noted that each of the arms of the I-beam are provided with a T-shaped slot so as to permit the I- beam to be used with lacings extending in three different directions.

In FIG. 5 is shown a box type beam having a pair of U-section chords 1% spaced and connected by continuous angular l'acings 12.

A straight section of extruded lacing 2ft shown in FIG. 6. As illustrated in FIG. 6, the lacing 20 corresponds to the lacing 14 of FIG. 3. In FIG. 7 the section of lacing 2% of FIG. 6 is shown formed into the continuous angular lacing 12 of FIGS. 1, 2, 3, 4 and 5.

To provide the joints, at the localities 22 of FIG. 1, between the chords and the lacings 12, the extruded lacing section as it comes from the extruding die prefably has some such cross-sectional shape as shown in FIG. 8 consisting of two similar and opposed T-shaped arms 2%, a T-shaped arm 26 at 90 thereto, and a simple flange 28 which is shorter than either of the arms 24 and 26 for reasons hereinafter set forth. The preparation of the section 20 to provide the lacing 12 of FIG. 7 is illustrated in FIGS. 9-14, inclusive.

'FIG. 9 shows an enlarged fragmentary portion of the angular continuous lacing 12 of FIG. 1 at the location at which the compression and tension portions 30 and 32 converge to merge with the joint portion 34 which is disposed in parallel relationship to the chord 10. In FIG. 9 the lacing 12 is shown after the bending operation which converts the straight extruded section 20* of FIG. 6 into the zig-zag or angular lacing 1-2.

To enable the male T-shaped arm 24 of the lacing 12 to enter the female T-slots 36 of the chords 10, 16- and 18, it becomes necessary to provide clearance paths through the flanges of the T-shaped arm 24 at the points 33 where the angular portions 39 and 32 merge with the joint portions 34. These paths, as shown in FIG. 10, may be ob tained by coining or milling the flanges 24 on opposite sides of the shank 24" of the T-arms 24. The portions of the flanges 2 between the paths 38 constitute the joint flanges 24" which are in shear in the joint between the chords 10 and the lacings 1-2 in a plane normal to the length of the structural memben.

To place the joint between the chords 10 and lacings 12 in shear along the length of thestructural member, staking of the telescoping male and female portions of the chords 1G and lac-ings 12 has proven satisfactory. As

shown in FIGS. 12 and 14, a transverse slot 41) has been oils or waxes are used, degreasing after assembly may be' avoided by incorporating an abrasive, such as aluminum oxide, in the oil or wax. With the chords 10 and lacing 12 assembled, the walls defining the T-slots 36 of the chords 1% are transversely deformed by a staking operation, preferably inwardly toward each other at the locality of the slots 40. The staking operation may be carried out in any suitable manner such as a punch press or by a portable hydraulic :sque-ezer having suitable punches 42, as illustrated in 'FIG. 16, to-provide the depressions 44 and 46. As clearly indicated in FIG. 17, the wallsof,

the lacing 12 defining the slot 40 have been brought into intimate shear relation with the walls defining the Telot 36 of the lacing 12 along the length of the structural member.

Tests have indicated that the staking operation between the chords 10 and lacings 12 gives the best results when localized directly adjacent the point of interseotion of the converging longitudinal axes of the tension and compression portions 30 and 3 2. In a truss the portions 30 and 32 are equally loaded. By keeping the length of the portion 34 to a minimum and the staking operation localized as above indicated, the joints between the chords 10 and lacings 12 will develop the full strength of the chords and lacings of the structural member.

In FIGS; 18-23 inclusive, in lieu of the slot 40, that portion of the lacing 12 which is received in the T-slot 36' is shown coined in FIG. 18 to provide clearance paths 38' and sheared notches 48. Punches 50, indicated 'in dotted outline in FIG. 22, deform the walls defining the T-slot 36 to provide the series of depressions 52. FIG 23 oated'on the inside and the wall structure defining the T- shows the intimate shear relationship which results from the walls defining the T-slots 36 being displaced into the notches 48.

In FIGS. 22 and 23, a slightly modified chord 10 is shown in which the outer faces of the chord angle are straight sided with the bead 54 about the holes beingloslot 36 being entirely located to one side of the outer side of the chord angle 10'. This differs from the cross-section of the chord 10 which has a rib 10" at the corner to stiffen the same, with the wall structure defining the T- slots 36 projecting beyond the face of the chord the same distance as the rib 10". The flange 28 of the lacing 12 projects the same distance as the rib 10" as does the bead above the holes in the chord 10. Suchan arrangement provides a good bearing surface for bolting other structure of the outer face of the chord and lacing assembly.

The principles of the invention may be utilized with individual lacing members extending between the chords as a substitute for the continuous lacing shown. Also, it 7 is to be understood that walls defining the .T- slots 36 and 36 may be closed by coining upon opposite side of the portion 34 of the lacings 12 and 12 as well as at opposite ends of the portion '34. This coining uponthe opposite sides of the portion 34 would be in addition to the localized coining which produces the depressions 44, 46 and 52 and its purpose would be to take up the sliding clearance between the T-slots 36 and T-shaped arms 24 which is necessary for the initial assembly. It will also be appreciated that the male and female components ofthe chord and lacing which telescope with each other may take many shapes and forms.

The use of a staking operation to place the chord and lacing in shear along the length of the chord has been found to be a very practical and effective method of preventing relative movement between the chord and lacing when the structural member is under load. However, other means for accomplishing the same result will be obvious to those slcilled in the art such as the use of a shear pin, welding, and the like, at each joint between the chords and lacings.

We claim:

1. A method of making an aluminum structural member having chord and lacing members in which said members are attached by a mechanical joint defined by said members comprising the steps of extruding said members with complementary shaped telescoping portions, shaping the lacing members into sinuous form to provide spaced points of attachment, shaping said points of attachment to permit telescoping of said complementary shaped portions, locating said points of attachment of said lacing members along the said chord members by relative axial movement while in their telescoping state, said members being in intimate shear relationship in a plane normal to the direction of said axial movement, and distorting at least one of said members in their telescoping association into intimate shear relationship with the other of said members in a plane angularly disposed to said first plane.

2. A method as defined in claim 1 including the additional step of lubricating the telescoping connection between said members With an unset adhesive and then setting the adhesive after said distortion.

3. A method as defined in claim 1 including the addi- 6 tional steps of lubricating the telescoping connection with a resinous material and then curing said material after said distortion.

4. A method as defined in claim 1 including the additional step of lubricating the telescoping connection with an epoxy resin and then curing said resin after said distortion.

5. A method of making an aluminum structural member tfrom extruded chord and lacing members including the steps of extruding said members with longitudinally extending complementary tongue and groove portions adapted to telescope one within the other to provide an intimate shear relationship between said portions in a plane normal to said portions, forming said lacing member into a sinuous form to provide spaced points of attachment with said chord members, providing a path of clearance for the lateral mating of said chord members with said lacing members at said points of attachment, and distorting said members to provide intimate shear relationship between said members in a plane angularly disposed to said first plane to effect a localized anchorage of the converging lacing portions at the intersection of said portions with said chord members.

References Cited in the file of this patent UNITED STATES PATENTS 954,900 Stragiotti Apr. 12, 1910 1,824,076 Dale Sept. 22, 1931 2,172,806 Pmobeck Sept. 12, 1939 2,388,297 Slaughter Nov. 6, 1945 2,627,649 Matthysse Feb. 10, 1953 2,642,920 Simon June 23, 1953 2,662,272 Macomber Dec. 15, 1953 2,863,533 Clevett Dec. 9, 1958 2,864,471 Williams Dec. 16, 1958 2,870,533 Benham *Jan. 27, 1959 2,961,757 Morin Nov. 29, 1960 2,967,161 Hart Jan. 3, 1961

Claims (1)

1. A METHOD OF MAKING AN ALUMINUM STRUCTURAL MEMBER HAVING CHORD AND LACING MEMBERS IN WHICH SAID MEMBERS ARE ATTACHED BY A MECHANICAL JOINT DEFINED BY SAID MEMBERS COMPRISING THE STEPS OF EXTRUDING SAID MEMBERS WITH COMPLEMENTARY SHAPED TELESCOPING PORTIONS, SHAPING THE LACING MEMBERS INTO SINUOUS FORM TO PROVIDE SPACED POINTS OF ATTACHMENT, SHAPING SAID POINTS OF ATTACHMENT TO PERMIT TELESCOPING OF SAID COMPLEMENTARY SHAPED PORTIONS, LOCATING SAID POINTS OF ATTACHMENT OF SAID LACING MEMBERS ALONG THE SAID CHORD MEMBERS BY RELATIVE AXIAL MOVEMENT WHILE IN THEIR TELESCOPING STATE, SAID MEMBERS BEING IN INTIMATE SHEAR RELATIONSHIP IN A PLANE NORMAL TO THE DIRECTION OF SAID AXIAL MOVEMENT, AND DISTORTING AT LEAST ONE OF SAID MEMBERS IN THEIR TELESCOPING ASSOCIATION INTO INTIMATE SHEAR RELATIONSHIP WITH THE OTHER OF SAID MEMBERS IN A PLANE ANGULARLY DISPOSED TO SAID FIRST PLANE.

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