US1770507A - Synthetic lumber - Google Patents

Description

July 1.5, 1930. A- F- BEMIS 1,770,507

SYNTHETIC LUMBER Filed Nov. 20, 1926 Patented July l5, E93

ALBERT F. IBEMIS, OF NEWTON, MASSACHUSETTS, ASSIGNOR TO BEMIS INDUSTRIES, ING., OF BOSTON, MASSACHUSETTS, A CORPORATION OF DELAWARE SYNTHETIC LUMBEB Application led November 20, 1926. Serial No. 149,764.

tions of walls, floors or roofs and are required to have a moderate degree of strength.

The invention more particularly pertains structural to the formation of composite lumber fromv4 loshcets or laminations of fibrous material prefof high humidity. Preferably the fiber -board is provided with a rough, irregular, or

semi-villous surface whereby it'may be firmly bound to the cementitious core and whereby the outer surface of the lumber may be adapt- 55 ed to receive plaster, stucco, etc. In proportion to its strength and moisture resistant qualities it is comparatively light and may provide very good heat insulation, while having better nailing qualities than either the 60 conventional'ber board or the conventional gypsum slabs; and furthermore, it may be easily worked or shaped by ordinary carpenters tools and may be handled, piled and shipped without requiring special care. 65

erably liber boardand frangible plastic or a The above and further advantageous feacementitious material such as gypsum or the like. Heretofore it has been common in the art to provide thin ber boards which have had certain inherent defects, such as a tendency to warp, inability to resist moisture, exi cessive expansion and contraction, only moderate compressive and tensile strength, rather poor nalling qualities and the like. It has also been usual to provide slabs of cementitious material, such as gypsum, with thin fibrous covering sheets of flexible material, such as paper or cardboard; slabs of this character having low tensile and bending strength, poor heat insulating qualities, comparatively poor nailing qualities and a tendency to break or crack easily, as well as being l particularly difficult to ship and handle.

Furthermore, this material is comparatively.

heavy` in proportion to its heat insulating qualities and tensile or bending strength.

The present invention by combining the characteristics of the separate materials indicated above provides a building material which has the advantages common to both of the ty es of materialpreviously used, with the disa vantages thereof reduced in degree or eliminated, thus being suited to a wide range of uses. The synthetic lumber disclosed herein, which comprises fiber boards located at either side" of a frangible core, has compartively good tensile and bending strength aswell as a satisfactory degree of compressive strength and does not have an objectional 5e. tendency4 to swell or warp under vconditions ythe material.

The composition lumber herein disclosed may be made of many suitable materials, but preferably includes outer layers of fiber board so having considerable inherent stiffness or tensile strength, for instance, material formed of felted vegetable fibers such as wood bers, or material, which is made from bagasse fibers v which have been only partially cooked and a5 therefore retain substantially .all their original strength; these materials possessing numerous interstices or air cells so that their heat insulating qualities are comparatively' high and having rough, somewhat vlllous Sul- 'faces to permit'mtimate bonding with cementitious material. Rather than material of this character a ber board having the characteristics commonly associated with other ordinary fibrous wall boards may be used.

Between the liber boards 1 of such a character, is poured or otherwise located plastic material 2, such as calcined gypsum, with or without suitable aggregate; preferably pressure isthen applied to Ainsure intimate bond- -v ing of the bers and the plastic material. For manyipurposes the thickness of the gypsum layer and of each of the ber boards preferi ably may be substantially equal, but the thickness of the laminations may be somewhat varied in order to adapt the lumber to individual uses and installations. For example, in a case where heat insulation is'particularly desired, the ber board, insulite or celoteX layers may be made thicker, while in other cases where moisture resistance is a prime requisite, the inner gypsum core may be somewhat thicker. The outer ber board laminations and the gypsum core may be unitedvby Yany suitable means, but preferably in such a manner that a rough brous surface of the board may firmly unite with the plastic material as it hardens, so that a strong union or bond is formed between the laminations of the lumber as designated by the numeral 8.

When it is desired to provide thick slabs or beams of this material, it will ordinarily be found advantageous to use several laminations of cementitious Amaterial and of ber board in the manner illust-rated in Fig. 3

rather than using thicker layers of ber and gypsum..V

i omposite lumber of this type, which combines the separate advantages of the materials found therein, will be found adapted to a much wider variety of purposes. In its preferred embodiment when manufactured of materials such as referred to above, the outer layers will provide convenient means for applying stucco, plaster, or the like, due to the rough, brous surface which is a natural characteristic of this type of ber board; obviously, however, the lumber may be provided with a nished surface in any conventional manner, and in certain cases a gypsum slab may form an outer layer of the lumber. The

lumber may be readily handledland shaped,

- posesses greater structural strength and betternailing qualities than its component mai terials, and furthermore it provides satisfactory heat insulatiomdoes not tend to expand, Swell, or warp appreciably when exposed to high humidity or a high temperature and is comparatively re resistant, while it possesses the ability to absorb rather than reect sound waves.

I claim:

1. A sheeteof wall board comprising'outer layers of form retaining ber board and an intermediate frangible layer of cementitious material which is bound by its inherent adhesive nature to the ber board.

2. A sheet of Wall board comprising outer layers of form retaining ber board and an intermediate frangible layer, said ber board having a roughened outer surface suitable for holding laster or stucco.

3. A s eet of wall board comprising outer layers of form retaining ber board and an intermediate frangible layer, said ber board providing heat-insulating layers.

4. Synthetic lumber comprising alternate layers of stiff, substantially form-retaining ber board and of cementitious material, said ber board having rough surfaces bonded to the cementitious material, the outer faces of .said lumber being formed by the ber boards whereby the cementitious material is protected against breaking.

5. A sheet of artificial lumber having relatively thick, light, form-retaining layers of cellular fibrous material having numerous interstices, and an inner layer of cementitious material, said outer layers constituting cush-` ening means for the cementitious layer, and

providing a board having good nailing qualities, said outer layers being at least of approximately the thickness of.; said cementitious layer.

7. A sheet of artificial lumber havingY light, form-retaining outer layers of cellular fibrous material having numerous interstices, and an inner layer of cementitious material, said outer layers constituting cushioning and stiemng means for the cementitious layer, and providing a board having good nailing qualities, said outer .layers being of substanially the thickness of the inner cementiticus a er.

ySined b me at Boston, Massachusetts,

this ourth ay of November, 1926.

Y ALBERT F. BEMIS.

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