US2263198A - Process for making wood joints - Google Patents

Description

Nov. 18, 1941. v F VALITON' 2,263,198

PROCESS FOR MAKING WOOD JOINTS Filed May 17, 1940 Patented Nov., 18, 1941 UNITED STATES PATENT OFFICE 2,263,198 I 4 rnocnss on MAKING woon JOINTS Frederick c; Valiton, South Ashburnham, Mass. I

Application May 11, 1940, Serial No. 335,832

"1 Claim. v(on. 142-309) F This inventionv relates to the art of making wood tenon joints as applied tochairs and other articles of furniture.

Objects of the invention include the provision of an improved tenon joint for furniture, such as for the legs, backs, and rungs ofchairs and other articles, in which the joint connection is made so as to greatly increase the rigidity of the article and life of the joint; the provision of means in the tenon for the reception and passage of glue to insure the spread and flow of the same; and the provision of such means having a criss-cross pattern on a compressed tenon, whereby peripheral and longitudinal threads. of glue .are formed to more securely hold the tenon, and longitudinal passages are arranged to allow escape of the glue from the bottomof a hole into which the tenon 3 is inserted, while the compressed material expands under its own resilience and due to the liquidity of the glue, to form an extremely tight, firmly secured joint.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawing, in which I Fig. 1 is a view in Joint to which this invention pertains;

Fig. 2 is a section of the improved joint;

Figs. 3 and 4 are elevations of an end of turned stock from which the improved tenon is to be made; i

Fig. 5 shows the end of the stock after compression;

- .Fig. 6 is an elevation of the completed tenom.

Fig. 'l is a planview of the tenon, looking in the direction of arrow! in Fig. 6; and

' Fig. 8 shows the new tenon joint used in conin various relations wherein such joints can be,

conveniently utilized. The mortice l2 maylbe plain and conventional, and one of the advantages of the invention isthat the improved holding action of the joint does not depend on any changes in the mortice or in its walls.

Turning to Figs. 3 to 7, it will be seen that to make the tenon joint of the present invention, a

down as at It to a diameter slightly larger than the size of the mortice into'which it is to be Next, the spaced longitudinal grooves are cut into the compressed area, the grooves extending only from end face 22 to the abutment shoulder 24, the latter acting as a stop, for the insertion of the tenon into mortice l2, as shown in Fig. 2. Then the spaced peripheral indenta-' tions 28 are cut or pressed into the areas comtaining the longitudinal grooves, and these in--:

dentations are made deeper than the grooves, as

' ,shown. Incidentally, it is possible to cut grooves 20 and indentations 26 prior to the compressing step, and in any case it is better to insert the tenon into the mortice so onafter the compression.. This time element is not essential, since it takes a long interval for the material to exelevation of one form of pand t'o approach its original diameter, and in fact inmost cases the expansion will never be as great as the original compression, in the absence of absorption of a liquid to swell the fibers. However, the sooner the compressed end l8,is insertturned member 16 is first provided, and this member may taper as shown, if .desired. The

small end of the member l6 isthen evenly turned ed in its mortice, the easier it is to force it.

The tenon having been made, glue is applied as T usual to .the face 22 and the teno'n is forced.,into

its mortice 12. In the absenceoil-grooves 22, the glue will merely remain in the bottom of the closed mortice, and will not run up the sides of the tenon, as theflt is made too tight to allow such action. Hence the only holding areaof the glue will be on face 22, and the more the leg [6 is forced towards the seat ll, the more pressure is exerted on the glue which in some cases has been known toforce a fracture in the reduced portion 30 at the bottom of the mortice.

However, the tenon having been provided with the. grooves 22, .the pressure on the glue at the bottom of the mortice will cause it to be forced along the grooves outwardly,'and in its passage, the glue will sink into the deeper indentations .26 and fill the same. When the first indentation of the tenon, and the grooves 22 will form longitudinal threads, and this, in conjunction with the expansion of the tenon, due to natural resilience of the wood, and also to the absorption of the liquid glue, will form an extremely strong and long-lasting Joint, having a, criss-cross pattern oi! compressed glue-holding areas. The peripheral threads of glue will always be formed, due to the fact that the indentations 26 are deeper than grooves 22, and the glue naturally therefore flows into them.

Even in cases where a hole is bored to form a mortice thru the seat member II, as in back posts, as illustrated at 32 in Fig. 8, the crisscross pattern allows for the spread of the glue, and the expansion of the compressed member will force the resultant threads of glue into very close contact with the walls of the mortice.

In the conventional tenon joint, it cannot be insured that the glue will contact the side walls of the tenon or mortice, and if the tenon is made small enough to force the glue backwards, the Joint will soon dry out and the glue will crack and become'loose, thus losing the holding power of the glue. The present invention provides for a very tight joint which still has a positive glued area, andv which can be assembled with no more trouble or expense than the conventional joint,

it only being necessary to compress and cut the tenon beforehand as described.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the grooves, and swelling said tenon in said mortice to form a tightjoint between the straight sides of the mortice and the lands of the tenon by applying liquid glue to the tenon prior to insertion thereof in the mortice, said glue filling the' grooves; and forcing the tenon with glue applied into the mortice, said swelling having the effect of forcing some of the glue into the wood of both tenon and mortice but principally into the latter due to the compressed nature of the tenon, the tendency of the tenon to return to its original size also aiding in the swelling action.

FREDERICK' C. VALITON.

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