US2391049A - Internally insulated structural unit - Google Patents

Description

Dec. 18, 1945. c. R. WEILLER INTERNALLY Y INSULATED STRUCTURAL UNIT Filed June 20, 1944 I I I IN VEN TOR.

arrow/5y Patented Dec. l8, 1945 ourrao STATES PATENT orrics I 2,391,949 mrsnmmr INSULATED STRUCTURAL UNrr Charles B. Weiller, Louisville, Ky., assignor to Reynolds Metals (30., Richmond, Va., a corporation of Delaware Application June 20, 1944, Serial No. 541,142

2 Claims.

posed upon the structural element, the metallic elements will coact one with the other and with the core, to adequately resist compression and tension strains. 7

In my preferred form, the metallic elements consist of aluminum alloy sheets, the alloys being selected to provide greatly augmented resistance to stress as compared with metallic forms of commercially pure aluminum. It will be understood, however, that the sheets may be made of metals and metal alloys other than aluminum. By aluminum alloys, I mean in the present instance, alloys which are predominantly aluminum, but which incorporate other metals to provide increase in yield and other strengths.

My invention is particularly applicable to buildings constructed largely of metal inasmuch as the conduction of heat from inner or outer wall which would occur with all metal beams and risers, is prevented.

One of the problems overcome by my invention is the effect of expansion and contraction upon a. composite structural form, embodying a plurality of metallic sheets, preferably of aluminum alloys, and a core such as wood, to wit: that in the wide range of temperatures to which such a structural element is subjected there is high expansion and contraction of the metal and very much less expansion and contraction of the cellulosic core. For this reason in expansion of the metallic elements, there is a strong tendency toward separation of the metallic elements from the cellulosic core, to such an extent that up to the present time, so far as I am aware, such structural elements have not been considered commereially practical.

As an example, the coefiicient of expansion of aluminum and many aluminum alloys in sheet form is .00001234. This means .that a strip of aluminum 100 in. long will have an elongation between the lower temperature of F. and 100 F, of .148 in. When it is considered, however, that ordinarily the aluminum alloy sheets in the core in commercial assembly and cohesion will be subjected to very much re t tures at the upper range, and then be brought down to room temperature, this factor causin great expansion and contraction of the metal, the Problem will be realized.

In view of the above, it will be seen that in one phase of my invention, means are employed for overcoming the effect of expansion and contraction of the metallic elements relatively to the cellulosic core.

In a second and primary phase of my invention, the metallic elements are so related to each other and to the core, that upon the imposition of stresses, as by normal loads, relatively thin aluminum alloy sheets will coact with very high eificiency to resist such loads. For this reason, very light constructions may be employed for the normal uses in building construction, as for example, floor beams, truss arrangements, division uprights, lateral wall risers, etc., etc.

In describing the invention with reference to the drawing, certain simple structural forms have been illustrated, these forms comprising four types of structural members adapted for use as vertical and horizontal supports and for general structural use. i

In the drawin Fig. 1 is a perspective fragmentary view showing an I-beam adapted for use as a floor or ceiling beam and embodying the invention,

Fig. 2 is a view similar to Fig. 1 showing one top plate removed and part of the vertical rib, broken away, to illustrate formation of one type of core adapted for use herein.

Fig. 3 is a transverse section through a channel beam embodying the invention.

Fig. 4 is a transverse section through a T-beam embodying the invention.

Fig. 5 is a transverse section through an angle member adapted for corner wall support.

Fig. 6 is a schematic plan view showing wood core sections abutted and illustrating the lay of the grain in a preferred form of core arrange-' ment when natural wood is employed.

Referring to Fig. 1 of the drawing, I have illustrated at I an I-beam which may consist of wood core elements and aluminum alloy sheets. On each side of the I-beam an aluminum alloy channel member I is employed. Each channel member is separated by a core 2, which in the present example may be of natural wood. At top and bottom of the members I and 2 are transverse core pieces 3 which are covered on the outside by the metallic strips 4 which may be of the same strain-resisting aluminum alloy as the strips l.

Reference to Fig. 2 will show that employing my invention with a natural wood core, single- 2 v s,ao1,oao plypiecesmaybeusedthesriin shownas 'I'heT-beamillustratedinl'igtiscomposedof extending transversely of the central web and two abuttingcore'members, as of wood, indithe upper andloweriianges of thestructure,

In assembling the structure suitable adhesive maybeappiiedtotheinnerfaceareabetweenthe core 2 and the channel members I andthese elements brought together under pressure, and usually under heat. For example, Ican employ a thermosetting adhesive, this being possible because of the ability of the core members to follow the metallic members in their expansion and contraction. Thus, the channel members may be subjected to high pressure, in a suitable press, to bring their faces into flrm contact with the adhesive, and under heat and pressure the adhesive will become set and bond the metal and wood strongly together. Like action is bad when the core members 3 are applied to the The strips 4 may be applied and bonded to the core members 3 prior to assembly with the channel members I, but in usual practice the bonding pressure and heat (where heat is employed) willv simultaneously be applied to the strips I, and the surfaces of the channel members.

It has been stated herein that, in the form of the invention being described-the grain of the wood extends transversely of the metallic strips. Referring to Fig. 2, it will be seen that the core member 2 and also the core members I are compomd of abutting wood veneer pieces. Thus, the lines of abutment run withthe grain of the wood. The major expansion is longitudinally of the I-beam. As the metal expands, the wood may be considered as having an accordion action, because the wood structure is so arranged as to permit the metal to have such expanding and contracting effect upon the wood. Repeated tests of the structure under wide ranges of expansion and contraction have demonstrated that even with the use of a normal thermosetting adhesive having a very low degree of elasticity, the bond between the metal and wood is maintained without rupture. The structure is not only adapted for expansion and contraction under normal conditions of use, but will withstand such high degrees oftemperature as required for the setting and. bonding of the adhesive material, and required for transportation imder severe conditions of heat and cold, particularly where aluminfim is employed.

In the stress-resistance action of an I-beam constructed in accordance with the invention, and assuming that the beam is laid horizontally and that the major stress is imposed vertically thereon, the stresses are distributed according to the known distribution of stresses in a unitary steel Ibeam. In my combination, there is this mutual coaction: The web 2 of wood prevents inner curvature or collapse of the metallic webs. The wood web and cohesion between the wood and the metallic webs prevents outer curvature and collapse of the metal. When the beam is subjected to heavy loads, the collapsing stress cated at I, twoangle metallic sheet members i, and an outer metallic strip II.

The L-beam illustrated in Fig. Sis composed of an outer angle member, of formed metallic strip,

II, and alike but smaller angle member, II, with a core composed of abutting core members II,

.ll.asofwood.

Referringtol'ig. 6,1havesbownpartofone 'ofthecorememberalortascomposedotbutt ioinedwoodveneerpieceawiththegrainot eachpieceextending transversely of the coreso thatthezrainwilllietransverselyofthebeam or'other structural member as a whole. In the expansion or contraction of the metallic cover- 'andstressestowhichthestructurewillbesubupon the metal is perpendicular to the flanges.

The tensional resistance of the is substantial.

Referring to Fig, 3, it will be seen that the U-beam therein illustrated is composed of an outer metallic U-section 5, an inner metallic U-section t, and three cellulose core strips 1'.

metallic members iected in use. and these factors also will control the gauge of the aluminum alloy or other metal employed for the exterior surfaces. These factors, also, will control the elements of the structure shown in Figs. 3 to 5 inclusive. It will be further understood that the exposed edges of the wood or other cellulosic core members may besotreatedastorenderthemimperviousto moisture, fire-resisting and termite-proof.

Among the advantages of my structural form are light-weight in ratio to stress resistance, internal heat insulation, sound deadening by reason of the cellulosic core, fire-resistance, and adequate resistance against the action of termites and ingress of moisture. since the small exposed edge areamayreadilybesealed, asbyaluminum paint.

It will be understood that the structural units illustrated in the drawing, may widely be varied in form and proportions, being illustrated by the invention, what I claim and desire to secure by Letters Patent, being as follows:

1. An internally insulated structural member comprising a cellulosic core, composed of aplurality of angularly related elongated wood units,

each wood unit consisting of butt joined woodpieces with the grain thereof extended transversely of the structural member, and a plurality of metallic strips surfacing the core and bonded thereto, said strips being formed of strainsisting metal.

2. An I-beam structural member composed of an internal web-core of wood, opposed channel strips of metallic sheet bonded to the web-core, opposed flange core members of wood abutting the web-core and the flanges of the channel members, and surfacing strips of metallic sheet material bonded to the exterior faces of the flange cor members.

CHARLES R. WEIILER.

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