US2333597A - Writing and drawing tablet - Google Patents

Description

Nov. 2, 1943.

F. s. STRAUSS 2,333,597

WRITING AND DRAWING TABLET Filed Ma 20, 1943 INVENTOR- K"" L S, h uss BY v I KL H 1 ATTORNEY Patented Nov. 2, 1943 V WRITING AND DRAWING TABLET Fred S. Strauss, New York, N. Y., assignor to Harte & Company, New York, N. Y., a copartnership consistingyof Charles P. Beagan, Alan Shedlin, Fred S. Strauss, Ann Shcdlin, and

Molly Strauss Application May 20, 1943, Serial No. 487,738 6 Claims. (or. 35--66) This inventionrelates to improved writing or drawing tablets.

In particular, the invention relates to a drawirig or writing tablet of the type in which the visible line of writing or the like results from the temporary adhesion to a waxy base, of a relatively opaque sheet when pressed thereagainst by a stylus or the like.

Writing or drawing tablets for temporarily receiving written impressions are known in the art. Said tablets conventionally include a base plate of stiff material, such as heavy cardboard, having applied thereto, a layer of pigmented waxy material. Overlying said pimented waxy surface for cooperation. therewith, is a tissue sheet, pref erably relatively opaque. 'Said tissue sheet may be of paper or cellophane, the latter being treated for opacity. I

The tissue or impression sheets employed with such prior art devices are characterized by irag'ility and susceptibility of disintegration under normal conditions of use, shrinkage and wrinkling from moisture, and relatively weak adhesion to the waxy base.

According to my present invention very substantial improvements in operation and materially lengthened useful life results from a suitable combination of a waxy, pigmented base and fine-weave cloth relatively thinly coated with a synthetic oil-base resin. The thickness of the resin coating, at least on the side of the fabric to be pressed against the wax, should be such that the threads of the fabric, while coated, are still discernible to the touch; a preferred resin has a somewhat oily property to improve the temporary adhesion to the pigmented base when pressed thereagainst by a stylus. The coated threads of the fabric penetrate the waxy surface to the limited extent permitted by the resinous coating, increasing the area of contact of the sheet with the waxy base and improving the brilliance of the resulting line and the adherence to the base.

The depression sheet, so constituted, is resistant against tearing, waterproof, and does not require an outer protective covering of Celluloid or the like as protection against damage by the stylus or other writing instrument.

An object of my invention, therefore, is an improved writing or drawing tablet for temporarily receiving legibl impressions.

An object of my invention is the provision of an improved writing or drawing tablet of the type aforesaid, employing as a principal writing surface, a fabric relatively lightly coated with a relatively hard, strong, oil-base resin having the property of temporarily adhering to the pigmented base.

Other features and advantages will hereinafter appear.

In the accompanying drawing:

'Fig. l is a perspective of a preferred embodiment of my invention, indicating the stage of obliterating written characters by lifting the impression-sheet from the waxy base;

Fig; 2 is anienlarged section, taken on lines 2-2 of Fig '1; Fig. 2 shows an optional additional waxy layeron the underside of the impression sheet; and l r Fig. 3 is an enlarged-fragmentary section showing the action of the stylus in urging the impression sheet into intimate temporary adhesion with the waxy base.

Referring to the drawing, my improved writing tablet l0 comprises a relatively stiff backboard l l of cardboard or fiber-board, on one surface of which isf-applied a pigmented Waxy base I2. Such pigmented coating may comprise a suitable relatively plastic material embodying any desired combination of filler, pigment and wax, mixed with a non-drying vehicle. The base 12 is given a smooth surface as by a suitable buffing step.

The impression sheet M is desirably a fine denier rayon fabric, coated, by impregnation or otherwise, with an alkyd resin coating it having the property of drying to a tough flexible film of somewhat oily character.

The resinous'coating .15, particularly on the side of the sheet In overlying the waxy base, should not be of such thickness that the surface of the sheet is smooth; in other words, the surface of the sheet overlying the waxy base should have a rather roughened surface attributable to the fabric texture. Such roughened surface is uniform throughout because of the weave of the fabric. The outer or writing surface of the sheet It may be as smooth and firm as is consistent with the coating step of the fabric.

When relatively soft waxes are used for the base material, no additional treatment of the sheet M is required. For harder wax bases, it may be desirable to coat the adjacent surface of the sheet 14 with a thin film of wax layer IE, to improve the adhesion between the sheet and the wax base under the influence of a stylus or like writing implement.

The herein described combination performs excellently for the reason, in so far as I am able to determine, by experiment and observation, that the pressure of the stylus or pencil H on the outer surface of the sheet I 4 causes the resincoated threads of the sheet to penetrate slightly into the surface of the wax base I l to the extent permitted by the resinous coating of the threads, as indicated in Fig. 3. The penetration or par- 5 tial penetration of the threads of the sheet l4 into the wax increases the area of adhesion of the sheet M with the wax base, resulting in a more intense marking and a more permanent adhesion of the sheet M with the wax base until the sheet is physically lifted out of contact therewith. I l

A merely "oiled silk or like fabric does not perform efliciently as the .writing; sheet be cause too great a penetration of the threads of a the fabric into the waxy base, -re sult s,'ni'arring or scarring said base in a manner detrimental to the life of the base; a heavily coated fabric, if the coating is of suitable character-does not afford the area of adhesion giving the clarity of line resulting from the use of fine-weave fabric hav ing the above-described characteristics. Animportantadvantage accruing from the employment of 'fabrics coated as aforesaid lies in the strength of the fabric and itss'tability, i.'e., freedom from shrinkage or wrinkling .under 5 humid atmospheric conditions. Although the use of a Celluloid sheet or the'like over the sheet I 4 maybe employed if desired, it is'not necessary, for the inherent strength of the coated sheet [4 adequately resists tearing orfracture in use.

Whereas I have described my invention byreference to specific forms thereof,'i t will be understood that many changes and modifications may be. made provided they do not depart from the scope of the claims. I I cla irnp 1. In a writing tablet, a backboard, a pigmented waxy layer thereon, andan impression sheet secured to said back board and overlying said Waxy layer in superficial contact therewith, 40 said impression sheet comprising a light, fine- Weave fabric having a coating of an oil-base resin wherein the'threads of the fabric are discernible 2,333,597 i J, T" V as a roughened surface at least-on that face of the impression sheet which faces the waxy layer.

2. In a writing tablet, a back board, a pigmented waxy layer thereon, and an impression sheet secured along one edge to said backboard and overlying said waxy layer in superficial contact therewith, said impression sheet comprising a light fabric offine, regular, weave, having a coating of an oil-base synthetic resin wherein the therewith-coated threads of the fabric are only slightly imbedded into the waxy layer under pressure exerted on the outer surface of said impression sheet by a writing instrument.

3. 'In awritingtablet, a back board, a pigmentedwaxy layer thereon, and an impression sheet secured along one edge to said backboard and overlying said waxy layer in superficial contact therewith, said impression sheet comprising a relatively light, fine-weave fabric having a relatively-thin coating of alkyd resin temporarily adherent to the waxylayer under the pressure of a stylus or'the like. h p 4. In. a'writing tablet, the combination with a relatively hard, ,waxy, base, of a resin coated sheet of fine-weave fabric adapted toadhere temporarily to said waxy base under the pressure of a stylus or the like, said falziric, having alight coating of relatively soft wax on its surfaceoverlying said hard, waxy base. I

' 5. In a writing tablet, the combination with a waxy, pigmented base, of a sheet of fine-weave fabric overlying .said base, said fabric having a light coating of synthetic oil-base resin applied thereto, wherein the threadsof the fabric are apparent to the eye as a series of intersecting, closely spaced, light-reflecting ridges.

6. 'In a device oftheclass described, an impression-visible, normally opaque, impression sheet comprising a relativelylight, fine weave fabric having a relatively. thin ,,coatiI1g-' of. an alkyd resin, whereinthe threads of the fabric are lightly discernible to .theJtou'ch. I f

4 V j FRED Sp STRAUSS.

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