US1555642A - Writing and drawing apparatus - Google Patents

Description

Sept. 29, 1925. v '1',5ss,s4z H. DEUTSCH WRI'I'IFNG AND DRAWING. APPARATUS Filed Aug. 2, 1922 FIG.I.

INVENITOR; I

may

to detach the paper Patented Sept. 29., 1925.

, nan-mm DE'UTSGE, or 'enoss-nonrnarnnnn; mean BERLIN,

GERMANY.

1; WRITING AN D DBAWIN G APPARATUS.

Application filed August 2, 1822. serial No. 579,217.

To all whom it may concern:

Be it known that I, HERMANN DEUTSCH, a citizen of Germany, Lichterfelde, near Berlin, Germany, have invented certain new and useful Improvements in Writing and Drawing Apparatus, of which the following is a specification.

This invention relates to a type of writing and drawing. apparatus which consists of a coloured ground plate or bottom plate coated with a layer. of paraffin or wax over which is spread a sheet of transparent paper upon which the writing or drawing is produced b means of a colourless style or pencil. Vahen pressure is applied to the paper .by the point of the style or pencil while guiding the said point over the paper as in writ ing in the ordinary way the paper at the lines along which pressure is applied is caused to adhere to the ground plate and writing or drawing of the colour of the ground plate then becomes visible on or through the paper. To obliterate the drawing or writing produced in this manner it is only necessary to dissolve the intimate contact between the aper and the plate or rom the ground plate, when the characters or drawing will immediately disappear. Hence the paper sheet may often be used before it is renewed. The known arrangements of this kind have the disadvantage that in making the marks small furrows are produced in the paper, which also entails considerable injury to e wax coating of the ground plate. Another disadvantage is that the paper is liable to be torn, so that the life of known contrivances of this kind is very limited.

The object of the resent invention is to overcome these disa vantages. This is accomplished by providing a transparent protective sheet above the paper sheet that is caused to adhere to the ground plate. The style, instead of being applied directly to the paper is applied to the protective sheet which consist of comparatively strong material such as celluloid, cellon or strong tracing linen. It has been found that a particularly eflicient kind of transparent protective sheet can be made of a pliable toil of transparent cellon which presents a very smooth writing surface, transfers to the paper sheet in a satisfactory manner the pressure applied to it by the style, and allows the characters or marks to become plainly visible. When a layer of cellon is used as a protective writing surresiding at Grossof the style, by which t face in this way, all injuries to the paper sheet are avoided and the cellon sheet itself does not suffer noticeabl from the action lie writing is produced. Another advantage obtained by using celluloid or cellon as a writin surface is that an ordinary lead penci may be used for producing the writing or marks if no other suitable style should be at hand, for the celluloid or cellon does not take the lead from the lead pencil or at any rate the graphite does not enetrate into it.

In certain cases it will be found preferable to unite the protective sheet with the paper sheet, which may be done by rolling the cellon' foil onto the paper sheet. The two layers, paper and protective layer, then form a single sheet so that both the paper I and the protective layer can only be raised or detached together from the ground plate.

The ground plate, paper sheet and also the protective layer or sheet may, if desired, be arranged in a frame, provided with suitable pockets or the like, ble. The arrangement can also be constructed in such a way that, to obliterate the marks, it is not necessary to raise the paper with its protective sheet. Instead of this the obliteration may be effected by placing a device between the transparent paper by means of which the so as to be exchangeaground plate and the paper, which has been caused to adhere to the ground plate as a result of the writin operation, can be detached at any desire part from the ground plate.

The invention is illustrated b way of example in the drawing, Fig. 1 ing a Ian view and Fig. 2 a section of one form 0 the device, while Fig. 3 is a section of a modification.

In the device shown in Figs. 1 and 2 a is a ground plate which may consist of cardboard coated with some suitable kind of adhesive material such as wax, paraflin or the like, I) is a thin sheet of transparent paper.

and c is a sheet of cellon or celluloid slightly i lifted irom the ground plate a. The words shown in Fig. 1 are merely to illustrate the clearness with which the device registers written matter and the ease with which the matter is made to disappear by lifting the two upper sheets as at the point C. p

In the modification shown in Fig. 3 the only difference is that the sheets b and c are united so as to form a single sheet. -Th1S unification can be effected by rolling the layer of cellon onto the paper sheet 6, or the two layers may be joined by means of a colourless glue. The manner of using the modified device is similar to the mo e of using the device of Figs. 1 and 2.

I claim:

1. A device of the kind described comprising a base plate with a plastic coating, a diaphanous sheet superposed-on said coating, and a substantially transparent glassysurfaced impressible sheet superposed on said diaphanous sheet, the coating and d1-.

aphanous sheet being adapted upon impressure of said sheet against said coatingto adhere along the lines of impressure.

2. A device of the kind described comprising a base plate with a plastic coating, a diaphanous s eet superposed on said coating, and a substantially transparent glassy-surfaced impressible sheet superposed on said diaphanous sheet, the base plate with its tic substance and adapte upon in ressure to adhere to said substance along t e lines of impressure, and a substantially transparent graphite-rejecting impressible tracing sheet superposed on said impression sheet.

4. A device of the kind described comprisin a base plate with a plastic coating, a diap anous sheet superposed on said coating, and a substantially transparent glassysurfaced impressible sheet superposed on said diaphanous sheet, the contacting surfaces of said sheets being united throughout the base plate with its coating and the di aphanous sheet difierin in color, the coating and diaphanous eet being adapted upon impressure of said sheet against said coating to adhere along the lines of impressure.

In testimony whereof I afiix my signature.

HERMANN DEUTSCH.

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