US 435313 A
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UNITED STAT S PATENT OFFICE;
FRANK R. H. LofIsE, OF ST. LOUIS, MISSOURI.
SPECIFICATION forming part of Letters Patent No. 435,313, dated August 26, 1890.
Application filed February 12,1890. Sierial No. 340,228. (No model.)
To all whom it may concern:
Be it known that 1, FRANK R. H. LOHSE, of the city of St. Louis, in the State of Missouri, have invented a certain new and useful Improvement in Cross-OutAnti-Warping Devices for Door-Frames, &c., of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification.
This invention relates to devices to prevent the warping of door-frames, &c., by the incision of cross-cuts of the grain in the stiles and cross-bars of the core-frame, so as to weaken the adverse warping power thereof; and the invention consists in features of novelty hereinafter fully described, and pointed out in the claims.
Figure I is a front elevation of a door in which my invention is incorporated,with parts broken away to show the construction of the same; and Fig. II is a horizontal section, taken on lines II II, Fig. I, and shows the anti-warp cross saw-cut in the stile of the door.
The conjoint construction of the doorframe need not be here diffusely described, as it is the subject-matter of another of my inventions and of another application for patent of even date herewith, Serial No. 340,103, so I will briefly note and number the several parts and afterward more definitely describe the elements of this invention.
Referring to the drawings, 1 represents the vertical stiles of the door-frame. 2 are the horizontal cross-bars that couple said stiles together; 3, the dovetail blind-mortises in the stiles, and at the blind-Sections at the ends of said mortises at the outer edges of the stiles that blind or hide the mortise and tenon i11- closed therein.
5 represents the ferrous; 6, the wedges that expand said tenons; 7, the split seats of the wedges; 8, the tongue-and-groove jointed panel-rails; 9, tongues of said rails; 10, grooves in which said tongues are seated, and 11 the channel-grooves in said rails in which the panels 12 are seated.
13 are the veneer-sections that cover the face of the stiles and cross-bars of the frame, and 14 are the vertical beads at the outer edges of the stiles, whose tongues 15 fit in the channel-grooves 16 in the outer edges of said stiles.
the frame out of true.
I now come to the description of the parts that are more especially the subject-matter of this invention and of the application for a patent made thereon, and first, as necessity is the mother of invention, I will point out the necessity that led the way to the invention itself.
However well the timber of which the frame has been made has been kiln-dried and seasoned,-it is found, especially with outer doors that are exposed to the vicissitudes of the weather, that in course of time the frame almost invariably commences to warp under the diverse and consequently adverse variable tension of the grain of the timber between the tenon-Inortise joints,which warps or casts Now it is also evident that said intervening sections of the stiles and cross bars have a superabundant degree of strength over and above that of their corelative parts occupied in the tenonmortise joints, parts of which are necessarily cut away. Another cause that exercises an influence of variableness in the shrinkage of the timber is that with the exception of the heart-boards oneside of the board is toward the heart and the other toward the sap, and said sides toward the sap under the same influence invariably shrink and swell more under the varying influences to which they are exposed than the opposite sides of the same boards. Now as it is the tension and throw of the grain that in consequence of the above conditions springs and warps the door and other frames, I provide cross-cuts or kerfs 17 of said grain in sufficiently numerous intervening positions between the tenon-mortises of both the stiles and cross-bars to weaken the adverse tension and projectile strength of said grain, and thus prevent or largely reduce its adverse action and the consequent warping of the door or other frame. Ieffect said cross-cuts by the straight insertion of a fine circular bench-saw alternately on each side of the stiles and cross-bars, thus effecting a circular out from each side, which respectively overlap each other, as shown in the section view in Fig. II. The kerfs may be effected by any other suitable means, and said kerfs are required to be left open, so that the tendency of the frame to warp may be thereafter continuously thwarted. There are preferably two tiers of said cuts in the bottom cross-bar of doors, and one tier in the stiles and other cross-bars; but I do not confine myself to the number of tiers. It will be seen that by effecting said cross-cuts of the grain of timber at locations along the stiles and crossbars that are not weakened by the construction of the tenon-mortise joints the adverse power of the grain to warp the frame is .reduced, and, in point of fact, it is found that the use of the above-described anti-warping device almost entirely overcomes the above prevalent tendency in door and other frames to Warp out of the true. The faces of the frames after putting together are preferably covered with the veneer 13, by which means the anti-warping cross saw-cuts are hid.
Among the practical advantages of this invention for the prevention of warping of doorframes, &;c., is that being unwarped and true set forth.
2. A strip or board having at intervals permanently-open kerfs 17 sawed therein and extending partly across the grain midway of the sides of the strip or board, substantially as and for the purpose set forth.
FRANK R. H. LOHSE.
In presence of- BENJN. A. KNIGHT, SAML. KNIGHT.