US1927000A - Plane table paper - Google Patents

Description

Sept. 12,- 1933. A. w. KEUFFEL 1,927,000

PLANE TABLE PAPER Filed Nov. 3. 1932 26 3Q 40 INVENTOR ADGLF m lfEl/FFEL BY/AA ATTOR Patented Sept. 1-2, 1933 i UNITED STATES;-

PATENT orrics This invention relates broadly to drawing and more particularly to-a drawing table and sheet material upon which a drawing is made, adapted for drawing table use. Q

' The primary object of the presentinvention is the provision or" a sheet material upon which drawings, sketches and the like may be made whichwill not change its dimensions under diiferent atmospheric conditions and which may be so secured thatthe securing devices do not interfere with the movement ofwinstruments, such as T-squares and triangles, over the drawing surface. The invention also'seeks the combination of a drawing table and a drawing receiving material such as paper or tracing cloth or the equivalent, the dimensions of which are unaffected by atmospheric conditions and which is adapted to be secured to the drawing table by fastening devices which shall not interfere with the movement of drawing instruments.

In accordance with the invention, the material, upon the surface of which a drawing may be made, is provided with a'reenforcement compris ing a sheet-like material which will not change its dimensions under different atmosphericaconditions and in the preferred embodiment is a lamination of some metal. interposed between paper or other laminations of fibrous material and so shaped that the reenforced lamination, at

least at predetermined areas,'extends beyond that reenforcing lamination a sufiicient distance to permit fastening devices to pass through tlie drawing receivingmaterial into a drawing table without passing through the. reenforcing lamina tion. More particularly, asheet of drawing pa per, say, is secured, by suitable adhesive, toat least one side of a sheet of metal which is cut away at thecorners and, conveniently, at predetermined points intermediate the corners, to permit the easy passageof securing means through the paper into the plane table.

The surface of the drawingtable may be depressed at a predetermined area or areas corresponding to the unreenforced or cut-out part or parts of the metal backing of the drawing paper so that the heads of the thumb tacks or othersecuring devices which overlie the paper maybe disposed ina plane beneath the. surface of the paper upon which the drawing, in major part, is

made. I

Within a depressed area, the drawing table may be provided with a wear resistant bushing, socket or the like adapted to removably receive a fastening device yieldingly threaded, or otherwise held therein and having preferably a broad fiat head to overlie the sheet material upon which the drawing is made.

Preferably, sheets of fibrous material, such as paperfare disposed upon both'surfaces of a reenforcing sheet of some desirable metal which is cut away at predetermined areas, andthe outer layers of fibrous material are drawn together over the cut-out portions and caused to adhere, as

by an" adhesive, so that the strain on the outer layers is evenly distributed.

These and other objects of the inventionand the means for their attainment will be more apparent from the following detailed description,

taken in connection with the accompanying drawing, illustrating one embodimentby'which the invention may be realized, and in which:--' v Figure 1 is a view showing,in plan',fa drawing table or plane table to'which a sheetof drawing paper is secured in accordance with this invention. Y v

Figure 'Z-is, an enlarged view, in plan, taken atone of the securing means for the paper, parts being broken away to show details of the paper.

Figure 3 is a vertical sectional View taken in the plane indicated by the line 33'of Figure. 1, looking in the direction of the arrows.

There is indicated, atlO, a drawing board or 7 plane table hereinafter referred to, for convenience, as a plane table, for the reason that the invention, willprobably find its greatest usefulness in connection with plane tables, so-called, but by the term"p1ane table is intended, broads 1y, any surface to which a sheet may be attached and a drawing made thereon. Predetermined' areas 12 in the top of the "plane table and proximate its four sides are recessed so that the paper may be depressed in these areas and the heads oisecuring devices may lie below the plane of the surface upon which the drawing or sketch is made. In'the illustrated embodiment, the depressions are formed by cutting out a portion of the upper surface of the plane table, of gradually increasing depth to the lowest point at the center where the fastening device is located, the depression being, conveniently, a. spherical segment in shape and hence circular in plan. 0 a

The paper, in accordance with this i vention, is so constructed as to retain its exact" dimensions and neither increase or decrease in size nor warp underdiiferent climatic conditions. To this end, a reenforcing sheet of material, which is unaffected by atmospheric changes, for instance, a sheet of metal 14, as thin as may be found practical,- is provided upon one surface with a sheet 16 of fibrous material, for instance, drawing paper,

tracing cloth or the like. For convenience in description, this sheet 16 will be referred to hereinafter as drawing paper to cover broadly any type of sheet material suitable for the purpose. In making the sheet of drawing paper, there is, preferably, first caused to adhere, upon each side of the reenforcing sheet, and by means of suitable adhesive, a sheet of fibrous material 18 capable of forming a bond both with the reenforcing sheet 14 and the drawing paper 16 on the upper side and a sheet 20 of fibrous material, such as paper of suitable characteristic on the under side of the sheet. Of course, both sheets 16 and 20 may be alike, but since only one side of the laminated sheet will usually be drawn upon, a less expensive sheet 20 can be used for the under side. The use of the bonding sheet is desirablealthough not necessary in all situations.

At areas of the drawing paper corresponding to the aforesaid depressions 12 in the plane table, the reenforcing sheet 14 is cut away or cut back from the edge, as shown at 22, and the sheets of fibrous material 16, 18 and 20 are somewhat larger than the sheet of metal 14 so that, preferably, on all sides, the fibrous material is drawn down over the edges of the reenforcing sheet including the edge of the cut-out portion 22 and joined together by suitable adhesive to forma laminated flexible sheet portion capable of permitting the passage therethrough of fastening devices and equalizing the strain on the paper and also capable of being depressed into the depressions 12, so that the heads of fastening devices may lie wholly within the depression and not obstruct the movement of drawing instruments thereover.

By gradually curving the surface of the depressions from the outer edge thereof to the fastening device, the laminated drawing paper is better enabled to conform to the surface without being subjected to undue strain which might rupture the bond between the sheets.

While any character of fastening device, such as thumb tacks, may be used to secure the laminated reenforced sheet to the plane table, there is shown, in the drawing, a screw and bushing fastening device which it is preferred to use with this invention. At substantially the center of each depression, there is formed a threaded hole 26 in the drawing board. This hole, conveniently, does not pass entirely through the drawing board. In this hole is received a threaded bushing or socket 28 ofsuitable material, preferably wear-resistant, such as brass, which is substantially unaffected by changes in atmospheric conditions and the bore 30 therein is of somewhat increased diameter at its upper end 32 to facilitate the insertion of a screw-like co-operating fastening member. The fastening member has a large fiat head 34 beveled on the underside, as at 36, the head being provided with a screw threaded shank 38, which is split as at 40. The shank is passed through a hole 42 formed in the paper and is passed down into the threaded bore 30 of the bushing. The slot 40 in the shank paper in drawing thereon. I

It will be obvious that any form of bushing or socket may be inserted in the board 10 within the area of the depression, it being merely necessary that the same be held in place and formed with means, for instance a hole, wholly or partly therethrough, to engage or receive the shank of a fastening device. Moreover the fastening device, while provided with a substantially flat head capable of overlying the drawing sheet at that point, may have a shank held in the hole either by a threaded connection or by resilient means.

While there has been shown one depression at each corner of the plane table 10 and one depression'along each side intermediate the corners,

it will be apparent that the numb r of fastening devices used will be dependent upon the size of the sheet to be affixed. Moreover, in some aspects of the invention plain thumb tacks or even clamps may be used to retain the paper against displacement.

Itwill thus be seen that a laminated drawing paper reenforced with sheet metal has been provided particularly adapted for use with a plane table or other drawing board or table, and so constructed and arranged that the fastening devices will not mutilate the board or interfere with the free use of drawing instruments.

Various modifications will occur to those skilled in the art in the composition and configuration of the plane table and the drawing paper as well as in the composition, configuration and disposition of the fastening devices, and no limitation is intended by the phraseology of the foregoing specification or illustrations in the accompany drawing, except as indicated in the appended claims.

What is claimed is:

1. A plane table formed with a plurality of depressions in its upper surface proximate each corner, in combination with drawing-paper comprising a reenforcement cut away to correspond with said depressions and fastening devices passing through the paper at the cut away portions and Entering the depressed portions of the table.

2. In combination, a plane table and reenforced drawing-paper comprising a sheet of material unaffected by atmospheric changes, a sheet of fibrous material affixed to one surface of said sheet material, said first named sheet having cut-out areas at predetermined points proximate its edges, said plane table being formed with a plurality of depressions in its upper surface corresponding to the cut-out area of said reenforcement and securing means for said drawing paper adaptedto engage said table within the areas of the depressions.

3. In combination, a plane table and reenforced drawing-paper comprising laminated sheet material, one sheet of which is unaffected by atmospheric changes, said last named sheet having cut-out areas at predetermined points proximate its edges, said plane table being formed with a plurality of depressions in its upper surface corresponding to the cut-out areas of the last named sheet, and fastening devices for the drawingpaper in said depressions comprising a member formed with a hole and secured in the plane table within the area of the depressions, and paper retaining means having a head to overlie the paper and a portion to be received in the hole.

4. In combination, a plane table and reenforced drawing-paper comprising sheet material unaffected by atmospheric changes and a sheet of fibrous material afiixed to one surface of said sheet material, said first namedsheet having cut-out areas at predetermined points proximate its edges, said plane table being formed with a plurality of depressions in its upper surface corresponding to the cut-out areas of the reenforcement, the surfaces of said depressions curving gradually from the edge toward thecenter, and fastening devices comprising a bushing secured in the plane table at-the center of each depression and a large-headed screw the shank of which is split and adapted to be removably received in the bushing, the head of said screw being of a thickness such as tolie within the" depression.

5. In combination, a plane table and reenforced laminated drawing paper comprising a sheet of material unaffected by atmospheric changes and a sheet of fibrous material aflixed to at least one.

surface of said first named sheet, at least one portion of said second named sheet projecting beyond the first named sheet and at least a corresponding portion of the surface of the plane table being depressed and adapted to receive,

securing means for the paper.

6. In combination, a plane table and reenforced laminated drawing paper comprising a sheet of material unaffected by atmospheric changes and a sheet of fibrous material affixed to at least both surfaces of said first named sheet, at least one portion of said second named sheets projecting beyond the first named sheet and caused to adhere togetherand at least a corresponding portion ofthesurface of the plane table being depressed and adapted to receive securing means for the paper. j

'7. In combination, a drawing-paper adapted to retain its shape under varying atmospheric conditions comprising a sheet of material unaffected by atmospheric changes and having cut-out areas at predetermined points proximate its edges, a sheet of fibrous material afiixed to both surfaces of said first named sheet material and extending over the cut-out areas and cause to adhere to-

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