US1987506A - Fire resistant veneered panel - Google Patents

Description

Jam i8, 1935. J. R. FlTzP'ATRlcK 1,987,506

FIRE RESISTANT VENERED PANEL Filed Jan. 23, 195s Patented Jan. 8, 1935 i i UNITED STATES FP1-CE 4 FIRE RESSTANT VENEERED PANEL James R. Fitzpatrick, Grand Rapids, Mich., assignor, byl mesne assignments, to Reconstrucgon Finance Corporation, a Federal corpora- Application January 23, 1933, Serial No. 653,046

3 Claims. (Cl. :Z0-91) The primary object of the present invention is in connection with the accompanying drawing, to produce-lumber in the form of strong, light wherein: y panels faced with wood veneers, which shall be Figure 1 is an elevation of a panel or a piece highly fire-resistant without `resorting to expediof lumber in the form of a panel embodying my 5 ents that may discolor the ne woods employed invention; Fig. 2 is a section, on an enlarged 5 as facings. scale, through the panel; and Fig. 3 is a view Bulkheads and partitions employed in the susimilar to Fig. 2, showing a modification. perstructure of ships should be made as light Referring to Figs. 1 and 2 of the drawing, 1 repas possible because, for every pound of weight resents a thick core, preferably of light maplaced above the water line of a ship there must terial. The core may be composed of balsa wood, 10 be a number of pounds placed below the water of Wood fiber or of wood composition. The core line in order to make the ship stable. 'I'hese extra is made up in the form of a panel of any desired pounds may be in the form of ballast or freight. width, limited only by the size of the presses in Consequently, any reductioninthe weight ofthe which multiple-ply lumber must be glued up,

l5 stateroom partitions in a ship means either that and of any desired length. Balsa wood is very 15 the ship can carry more freight, or that the light, and so are some of the wood ber or wood Whole weight of the vessel may be decreased very composition boards as at present manufactured.

much more than the reduction in weight of the Not only is a core made from any of these mapartitions and thus decrease the displacement terials light in weight but it has good soundand either increase the speed or decrease the deadening and good heat-insulating properties.

power required to drive the vessel at a given Glued to the two faces of the core are thin speed. Furthermore, it is important that these multiple-ply panels which stifEen and strengthen partitions be highly fire-resistant. Plywood posthe structure, provide the ornamental surface sesses properties that cause it at present to be finish, and give to the composite panel its calargely used for partitions and bulkheads in the pacity to resist fire. In thearrangement shown, 25 superstructure of ships, even though it does not these facing panels for the core are just alike, offer the desired degree of resistance to fire. In each being composed of a relatively thick memorder to make plywood'more suitable for these ber 2 of one of the lighter and cheaper woods, purposes attempts have been made to increase such as poplar, two layers of thin wood veneer,

its 'resistivity to fire by impregnating it with and a layer of asbestos paper. One layer 3 of 30 suitable chemicals. However, such impregnation veneer is cemented or glued directly to the inner results in discoloration ofthe facing veneers; or under face of the core member 2 whereas the and, since these facing veneers are usually of other layer constitutes the outer or facing layer.

' rare Woods selected because of their decorative The asbestos paper layer 5 is shown as being value, impregnation with chemicals is imprac located between the layers 2 and 3. 'Ihese rela- 35 ticable in such cases. Furthermore, the usual tively thin facing panels are preferably built up plywoods are reasonably good conductors of separately, and are then glued or cemented to heat and sound and, therefore, do not serve as the relatively thicker core to form the complete heat insulators or sound deadeners, both of which panel.

40 characteristics are desirable in the partitions and The Ordinary Sheet aSbeStOS 01 the mill bOald 40 bulkheads forming part of a ship superstructure. of commerce possesses very little shear strength v Viewed in one of its aspects, the present inand, if used to form the asbestos plies in my imvention may be regarded as having for its object proved product, makes it easy for the thin facing to produce a simple and novel panel possessing veneers to tear loose. I have found that by irnall of the characteristics desirable in the partipregnating commercial sheet asbestos or mill 45 'tions and bulkheads of a ships superstructure, board with resin, of the synthetic type, the asas described above, and, consequently, a panel bestos is suiiiciently strengthened, particularly adapted foruse wherever some or all of such insofar as its capacity to resist shear stresses is characteristics are useful or desirable. concerned, to make it possible successfully to em- The various features of novelty whereby my ploy the asbestos layers eveninvery large panels. 50

invention is characterized will hereinafter be The four plies of each facing panel are preferpointed out with particularity in the claims; but, ably assembled and united by glue or cement in for a full understanding of my invention and any usual or suitable way, and these facing panels of its objects and advantages, reference may be are then glued or cemented to the core, wherehad to the following detailed description taken upon my improved material is ready for use. 55

The completed panel possesses great strength for its Weight; it is self-supporting and requires very little bracing even in very large sizes; and it may be set in rabbets at the top and bottom and in pilasters where joints between adjacent panels occur, in assembling the panel in a ship or other structure. Regarding the weight of the material, it should be noted that the weight of the panel as a whole is not greatly increased by the presence of the thin layers of asbestos whereas, when it is attempted to render wood panels lire-resistant by treatment with chemicals, a considerable increase in weight results, such increase amounting sometimes to as much as twenty-five per cent. This increase in weight is, of course, a serious objection quite aside from the objection that the wood may be discolored by the chemicals. Furthermore, chemically treated panels quickly dull tools that are used in cutting into or through them; whereas my improved panels may be worked in the same way as any ordinary lumber and have no more effect on the tools than does such ordinary lumber.

With respect to its fire-resisting properties, it will be noted that, when a flame acts upon a face of one of my improved panels, it can burn away only the comparatively thin veneer layers 4 and 2 before striking the corresponding asbestos layer. The burning of this small amount of wood cannot produce a great fire and it can easily be put out. Consequently, the danger of a serious re resulting before attention can be attracted thereto is minimized. By actual test, one of my improved panels has withstood a five-inch Bunsen ame which has a temperature of from 1500 F. to 1800* F. for ninety minutes. At the end of that time it was found that the ilame had not penetrated the more remote layer of asbestos and that, although the panel was charred on the side in contact with the test flame, the remote or cool side was but slightly scorched and a good deal of the original strength of the panel remained. A similar panel, excepting that it did not contain the asbestos layers, was burned completely through in fifteen minutes. It was also found that with the Bunsen ame directed against one face of my improved panel, the opposite face remained comparatively cool. Wood scorching temperatures were attained only after twenty.- five minutes. This is of considerable importance because of the protection against any objectionable rise instemperature afforded bythe panel to anything behind it for a comparatively long time.

after a flame has reached the panel from the op posite side. A

Although the multiple-ply face panels may be glued up separately yet, in the completed structure, the core l together with the inner layer of each facing panel may be regarded as the body member that is faced on both sides with asbestos overlaid with thin wood veneer. Furthermore, While the inner thin veneer layers of the facing panels add strength to the structure as a whole,

-their principal function to hold the facing panels flat until they can be glued to the main core.

In some cases the asbestos layers may be placed directly under the outer thin facing layers 4, 4. Such a'construction is shown in Fig. 3. In this form of my invention there is only a. very thin skin of wood outwardly from the asbestos and therefore only an extremely small amount of material to support combustion, as long as the asbestos stands up, when the panel is attacked by fire.

It will thus be seen that I have produced a panel which, among other things, because of its thick, light core, weighs about one-half as much as an ordinary plywood panel of the same thickness, is rugged and self-supporting, is highly re-re- Sistant, acts as a heat insulator and to deaden sound, permits natural wood facings to be employed without danger of discoloration in the process of manufacturing the panel, and may be worked by ordinary wood working tools without dulling them.

The proportions or thicknesses of the several plies relatively to each other may, of course, be varied within wide limits. Ordinarily, in panels having a thickness of from seven-eighths of an inch to an inch and a half, the thin veneers 3 and 4 will have a thickness of anywhere from one forty-eighth of an inch to one twenty-eighth of an inch, while the heavier auxiliary core elements 2 will be from a tenth of an inch to an eighth of an inch thick. Variations in the thickness of the panel as a whole may be brought about by increasing the thickness of the main core and, also, if desired, of the auxiliary core elements 2. In any. event, assuming that Figs. 2 and 3 of the drawing illustrate panels having a thickness of an inch or so, it will be seen that these figures are drawn on a greatly enlarged scale.

While I have illustrated and described with particularity onlya single preferred form of my invention, with a slight modification. I do not desire to be limited to the exact structural details thus illustrated and described; but intend to cover all forms and arrangements which come within the definitions of my invention constituting the appended claims.

I claim:

1. A piece of lumber composed of a thick, light core and a multiple-ply panel overlying and cemented to each broad face of the core; each such panel consisting of plies of wood and an interposed layer oflasbestos impregnated with a fireresistant material for strengthening the asbestos, all cemented together.

A2. A piece of lumber composed of a thick, light core and a multiple-ply panel overlying and cemented to each broad face of the core; each such panel consisting of two layers of thin wood veneer, a layer of thick veneer, and a layer of asbestos impregnated with a synthetic fire-resistant resin; one of the thin veneer layers being cemented to the thick veneer and the asbestos being interposed between and cemented-to the other thin veneer layer and the thick veneer.

3. A piece of lumber composed of a thick, light core and a multiple-ply panel overlying and cemented to each broad face of the core; each such panel consisting of a layer of thin wood veneer next to the core, a layer of asbestos and, overlying the asbestos, a thick layer of wood veneer and then another thin layer of wood veneer.

JAMES R. FITZPATRICK.

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