US 2151505 A
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Description (OCR text may contain errors)
March 1939. A. ELMENDORF END GRAIN WOOD FLOORING Filed NOV. 19, 1936 Patented Mar. 21, 1939 UNITED STATES PATENT OFFICE 3 Claims.
The present invention relates particularly to a floor or floor covering of wood in which the wearing face contains end grain. The object of the present invention is to produce such a floor or floor covering which shall be much thinner than conventional wood block floors, and which can be laid in the form of flexible sheets.
A further object of the present invention is to produce a floor material or floor covering of the block type, which not only can be laid as flexible sheets but which, when laid, has its blocks securely tied to the underlying floor or subfloor so as to avoid the danger that individual blocks will become displaced, either laterally or upwardly or that large floor sections will at any time bulge upwardly asoften happens in the case of conventional block floors.
In carrying out my invention I produce a layer of comparatively thin wood blocks arranged in contact with each other, said layer having in one broad face thereof a system of deep grooves following joints between the blocks. These grooves are filled with a suitable yieldable or plastic binding material, such as asphalt. A thin, flexible backing is then laid upon this face of the layer of wood, and is secured to each block by a suitable mechanical fastening. I prefer to employ as the fastenings so-called metal stitching, which comprises little staples driven through the backing and into the wood blocks. There is preferably only a single staple for each block, driven into the block at about the middle of the face in contact with the backing. The material may be constructed in sheets or panels of any desired size which permits them to be readily handled and shipped. In laying the material, it is bonded to the underlying subfloor or other foundation, conveniently by means of such an adhesive, for example, as the paste commonly employed to hold down linoleum and the like. After the material has once been laid, it is held and cannot lift up bodily. Neither can the individual blocks rise, because each is held down by its mechanical fastening. The asphalt in the grooves serves also to keep the blocks in place, particularly under the jarring influence of trucks or the like running over the same. Because of the yieldable character of the binder, each block may expand and contract freely, but it simply becomes larger and smaller without any shifting bodily in any direction. Therefore, there is at no time any bodily shifting in the lateral direction of the floor as a whole. In other words, each block is anchored at a fixed point in the supporting foundation or subfloor and expansion and contraction of the wood results simply in the closing and opening of the joints between blocks and not in any actual shifting of the blocks themselves.
The various features of novelty whereby my invention is characterized will hereinafter be pointed out with particularity in the claims; but, for a full understanding of my invention and of its objects and advantages, reference may be had to the following detailed description taken in connection with the accompanying drawing, wherein:
Figure l is a top plan view of a fragment of a panel or sheet of flooring embodying the present invention; Fig. 2 is a bottom view of the material illustrated in Fig. l, a portion of the flexible backing being broken away; Fig. 3 is an edge view of the panel illustrated in Fig. 1; Figs. 4 and 5 are sections taken respectively on lines d-d and 5-5 of Fig. 1; and Figs. 6 and '7 are respectively a side view and a bottom view of a block having a somewhat different form than that in the previous figures.
Referring to Figs. 1 to 5 of the drawing, l represents a comparatively thin flexible backing sheet, such as reasonably thick tough paper or felt saturated to make it waterproof. Overlying this backing layer are tiles or blocks of Wood 2, of any desired size and shape, arranged side by side in engagement with each other. These blocks are preferably arranged with the grain of the wood therein running from top to bottom, so that the upper or wearing face of the assembly contains end grain. However, for some purposes certain features of the invention may advantageously be employed where the grain of the wood does not run more or less at right angles to the plane of the sheet or slab. My improved flooring, composed of blocks about an inch high and having end grain in their wearing faces, has given very satisfactory results. Such blocks may, if desired, be as wide and as long as they are high, this being about the shape which I have illustrated by Way of example,
The lower ends of the blocks are of reduced size so that when a group of blocks are placed together and form rows transverse to each other, there appears in the bottom face of the assembly a network of grooves which coincide with the joints between the blocks in the assembly. The first step in producing a thick composite sheet or slab is to set the requisite number of blocks upside down in a suitable form, after which the grooves are filled with a suitable binding material which remains plastic under continued stresses. Asphalt may advantageously be employed as the binder. The binding material may simply be poured or dumped on the assembled blocks and be scraped or otherwise worked over the face of the assembly until the grooves have become packed, and the excess binding material may then be scraped off. It is to a large extent a matter of choice whether the binding material be confined entirely to the grooves or whether a layer of greater or lesser thickness be also permitted to overlie the block assembly. If all of the excess binding material is scraped off, the face of the block assembly shows a network of strands or narrow bands of binding material, as indicated at 3 in Fig. 2.
After the binding material has been applied, the fiexible backing sheet I is laid on the assembly and is mechanically fastened to each individual block. I prefer to employ only a single fastening for each block, placed at about the center of the latter. These mechanical fastenings may conveniently be little metal staples 4 which can be quickly and accurately driven by a suitable socalled stitching machine.
The material is now ready for use. In laying it upon a subfloor, the side having thereon the backing sheet is placed next to the subfloor, as shown in Fig. 3, where the subfloor is indicated at 5. Each sheet or slab as it is laid upon the subfloor is bonded to the latter by a suitable adhesive, conveniently of the kind employed in securing linoleums to a floor.
After the binding material between the flooring sheets or slabs and the subfloor has set, each block is anchored firmly to the subfloor and consequently, even if the blocks become wet to a degree that causes ordinary fioors composed of blocks set into asphalt to bulge upward, they remain down against the subfloor and the wearing surface of the floor proper remains fiat. Each block can expand and contract in directions parallel with the floor, independently of every other block, but cannot move bodily in a lateral direction any more than it can move upwardly. For this reason no bodily shifting of the floor in a lateral direction can occur.
If the wood contains from ten percent to twelve percent moisture at the time the flooring is laid, it is not likely thereafter to have a higher moisture content, assuming it to be a floor within a building. Therefore, starting with this moisture content, if the blocks dry out somewhat, they contract and the joints in the upper face of the floor open slightly; but, since the center of each block is held in a fixed position, there can be no cumulative effect in the opening of the joints that might cause wide cracks to appear in some parts of the floor. Then, upon again taking up moisture, the blocks simply expand and close up the joints.
The network of asphalt or the like does not prevent the expansion and contraction of the blocks, since it is sufiiciently plastic to yield satisfactorily to the slow movements of the meeting faces of adjacent blocks from and toward each other during contraction and expansion of the wood. The individual strands or elements of the network of asphalt should have sufiicient cross sectional area and sufficient vertical depth to insure that the bonds between the same and the locks will not be destroyed and that the strands will not be torn apart and allow water to flow downwardly through them, and to cause the binding material to hold each block down firmly enough to make it difficult for any block to tilt under forces to which it may be subjected due to the passing of the wheel of a truck or the like over the same. Were it not for this network of binding material, there would always exist the danger of tearing some of the blocks loose from the backing under lateral thrusts thereon caused by a heavily loaded truck passing over the same. Good results have been obtained by making the grooves of a flooring in which the blocks are not over one inch thick about a quarter of an inch deep. The grooves may be of any desired widths, and their cross-sectional shapes may vary. In Figs. 1 to 5, the grooves are rectangular in cross section, this result being obtained by cutting away the wood to a depth of somewhat less than an eighth of an inch from each side of each block for a distance of about one-quarter of an inch from the bottom face of the block. If it be desired that the grooves be triangular in cross section, blocks such as indicated at 6 in Figs. 6 and 7 may be chamfered along all sides, at the bottom, as indicated at 1.
While any desired bonding material may be placed between the flexible backing and the subfloor, the present invention, for the first time, makes it possible to employ an adhesive which sets in a non-plastic state. In the case of a flooring in which the blocks may shift bodily, so that a whole fioor or a large section thereof tends to move laterally as a unit, the bond between the backing and the subfloor would crack and permit the backing to tear loose, if the bonding material were of the type commonly used for fastening down linoleum, such bonding material becoming hard as it sets. Obviously, a much stronger bond results from an adhesive which soon becomes non-plastic than from a bonding material that remains plastic as does asphalt and, therefore, I am able to fasten down my flooring much more effectively than has heretofore been possible in the case. of more or less similar wood floorings.
While I have illustrated and described with particularity only a single preferred form of my invention, 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.
1. A preformed floor covering comprising a o flexible backing sheet and an overlying layer of wood blocks or tiles resting loosely on the same, said blocks being in contact with each other and having in their lower faces deep grooves following the joints between the same, a plastic binding material filling said grooves, and fastening means extending through said backing sheet into each block, the fastening means for each block being localized in an area which is only a small fraction of the area of the block, whereby each block is anchored while left free to expand and contract independently of the backing sheet under changes in moisture content.
2. A preformed floor covering comprising a flexible backing sheet and an overlying layer of wood blocks or tiles resting loosely on the same, said blocks being in contact with each other and having in their lower faces deep grooves following the joints between the same, a plastic binding material filling said grooves, and a single staple extending through said backing sheet into each block.
3. A preformed floor covering comprising a flexible backing sheet and an overlying layer of wood blocks or tiles resting loosely on the. same,
means for each block being localized in an area which is only a small fraction of the area of the block, whereby each block is anchored while left free to expand and contract independently of the backing sheet under changes in moisture content. 5