US 2257048 A
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SePt- 23, 1941 c. c. FULBRIGHT FLY WOOD FLOOR BLOCK Filed Sept. "7, 1940 'itat' E] wuz/WM immane fl'arln'f/ s@ 63 www; af W Patented Sept. 23, I941 UNITED STATES PATENT OFFICE PLY WOOD FLOOR BLOCK ClarenceC. Fulbright, Pine Blul Ark.
Application September?, 1940, Serial No. 355,868
The invention relates to iioor blocks and has as an object the provision of a floor block made from ply wood.
It is an object of the invention to provide a ply wood floor block. provided with tongues and grooves wherein the tongues involve portions of at least two plies.
1t is a further object of the invention to provide a ply Wood floor block in which the grain v shown as formed of five plies IIl I2, I3, Il-and I5 respectively. As shown the vgrain of plies II and I5 at opposite surfaces of the block run in the same direction, which results from the inclusion of an odd number of plies. As a result of such relation -of the direction of grain of wood on the oppositesides of the block, any swelling or shrinkage of the Wood caused by conditions which are common to the two sides,
as changes of humidity before the blocks are laid. will be balanced by the action on the two sides.
As shown the block is formed with tongues I6. Il on two adjacent sides and grooves I8, I9 on the remaining two sides, as is common practice. In accordance with the invention, the tongues involve 'at least two of the adjacent plies, I3 and I4 as shown, as a result of which the danger of splitting off of the tongues is obviated.
Furthermore, in the form of Figures 1 and 2 the portions of the block at each side of the grooves I8 and I9 also each involve at least two plies, for a like reason.
The grooves 20, 2| in the bottom surface of the block are conventional in floor blocks.
'Ihe form of the invention of Figure 3 comprises three layers 22. 23 and 24, the grain of which layers 22 and 24 at opposite surfaces run in the same direction. The tongues I6' (and I1' not shown) of this form of the invention involve the two layers 23 and 24.
The layer 22 which is exposed in the surface of the iioor and is conventionally made of superior material, as shown as thicker than the the tongue and groove by bodily offsetting one of the plies toproject at two edges and inset `at the remaining two. But the soft wood layer at the parallel grain projection, of soft wood, is very vulnerable to handling. By the structure of the present invention each tongue as well as the overhangs of the grooves are made equally strong on each .side of the block.
Minor changes in the physical embodiment of the invention may be made,.within the scope of the claims, without departing from the spirit of the invention;
1. A Iioor block comprising in combination: a plurality of plies of wood` united by an adhesive; tongues projecting from two adjacent edges of the block and grooves formed in the remaining edges; each of said tonguescomprising at least portions of at least two of the plies comprising the block; the grain of certain of said plies running at an angle to the grain of an adjacent ply.
2. A floor block comprising, in combination: a plurality of plies of wood united by an adhesive; the grain of alternate plies at an angle of to that of the remaining plies; tongues projecting from two adjacent edges of the block and the remaining edges formed` with grooves; each of said tongues comprising at least portions of at least twoof said plies; material overhanging at least one side of each groove formed of at least portions of at least two of said plies.
3. The structure of claim 1 in which the grain ofthe wood at opposite surfaces of the block runs in the same direction.
CLARENCE C. FULBRIGHT.