US308296A - Blackboard - Google Patents

Description

(No Model.)

No. 308,299@v W. H. WHITTEMORB.

BLAGKBOARD.

Patented Nov. 18, 1884.

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WILLIAM H. WHITTEMORE, OF DEERING, MAINE, ASSIGNOR OF ONE-HALF TO EDMUND S. I-IOYT, SAMUEL FOGG, AND GREN VILLE M. DONI-IAM, OF

PORTLAND, MAINE.

BLACKBOARD.

SPECIFICATION forming; part of Letters Patent No. 308,296, dated November 1B, 1884.

l Application filed December 1, 1883. (No model.)

.To @ZZ whom, z5 may concern:

Be it known that I, WILLIAM H. WRITTE- MORE, residing in (VOrdfords) Deering, in the county of Cumberland and State of Maine, have 5 invented certain new and useful Improvements in Blackboards; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others sinned in nie an to which n apparatus to Io make and use the same.

In the accompanying` drawings, forming a part of this specification, I exhibit views of' an improved writing board or tablet designed for various purposes and uses.

Figure l represents a board or tablet for use in schools for inap-drawing and teaching geography. Fig. 2 shows a tablet for use in railroad stations. Fig. 3 shows a tablet, pa'rtly plain and partly lined,i`or use in object-draw- 2o ing.- FigA. is avertical central section through the slate. "f

Like letters ol' reference in the several iigures indicate corresponding parts.

The invention has direct relation to a new and useful writing boardor tablet, which in use will prove to be very durable and easy of operati-on,and to possess many other elements ot' superiority over any of the many styles of blackboards, writing boards, sehool-tablets,

' 3o Src., now sold in the markets. To this end my invention consists in certain details of construction, which will be hereinafter fully described, and the special improvements which are believed to be new pointed ont in the claim.

3 5 In its mechanical parts my Writing-boardis very simple,consisti ng ofa glass writing-panel and a protecting-frame.

A shows the frame. This frame is usually made of strips of wood molding of any conven- 40 ient size and design.

B shows the writing-panel.. This panel is made of thick glass, roughened or ground on one side and perfectly smooth on the other. As the panel constitutlesl, th'e chief feature of my invention, I will describe its construction and method of preparation at some length.

As stated,the panel is made of roughened or ground glass. The roughened side I call the writing side, the sin oth side, the' back 5o side. An even coating of black paint, c, or

other black compound is applied to the back side of the panel. By reason of the transparent qualities of the glass the black coating on the back side is rellected through the panel, and the front side presents a black surface analogous to that of a common blackboard or slate-tablet. As soon as the black paint is thoroughly dry and hard. l rub the front side with einery-paper to reduce the sharp and rough points lei't by the grimung-machine. I next apply a bath ol vitriol to the vl'ront surface.y This vitriol bath continues about ten minutes, more or less, according to the state ofthe g/round surl'ace. ilhe action ol" the cin ery-paper and vitriol bath tend to remove all minute sharp points, which, il" allowed to remain, would act as liles lo wear oli.' the end ol" a pencil or crayon.

rlhe several steps enumerated having been taken, a writing board or lalili-.t is produced upon the writing-surface ot' which a slatepencil or chalk crayon can he used with the same results as when used upon au ordinary blael board or slate-tablet.

\Vhile the results are the saine, iny invention possesses certain very decided advantages over the ordinary form ot' blackboard, ete.

H ilhertointhe construction of lllaekhoards, tally-boards. e., the custom has been to make them so that the pencil or crayon came in direct contact with the black writing-surl'ace. This method ot' construction was detective, because the continuous use oil a pencil or other writing-point and the rem-ated :.tpplieations of an eraser all tended to destroy the luster of the writing-surlace and necessitate frequent renewals ot' the saine. 4ln the use ot' iny invention no sueh di'lliculty arises, because the writing-pointdoes not come in contact with the black surface, and cannot until 'the body oftheglasspancliswornthrough. Jhusitwill be readily seen that the wrt .ig-sm'tace .must remain perfect for an indeilnite period.

Vhen it is necessary le ,remore any pencil or chalk marks from the wrilzing-tairtiice, all that is necessary is to rnb the wriliiig-surtace with an eraser or moist cloth, and the surface will be left just as bright and lustrous as before.

To prepare my invention for a great variety of uses I have devised the following method: After the compound on the back side becomes lrd and dry l' place a stencil or other guide on it, and with a sharp instrument trace ly desired outline upon the back of the panel. lese traced lines are then illed with Sonie ightcolored paint, and the design stands lt plain and distinct on the front side. For ample, to prepare a tablet for map-drawing,

should stencil on the back of the panel the- .ould use large sheets of' ground glass, and t them firmly in the plastering of the wall. I am aware that heretofore glass has been roughened on ene side for use in drawingslates; also that paper-Weights and like devices have had pictures or figures pasted onl the back, so that the picture face or the figures could be readily seen from the upper surface of the glass.

What I claim my invention, and desire to secure by Letters Patent, is*- As an article of manufacture, a vitreous writingtablet having one side painted or covered with a black compound, and the other made suitably smooth by grinding and rub- I bing and treating, as described.

In testimony that I claim the foregoing as my own I have aiiixed my signature in the presence of two Witnesses.

VILLIAM H. VVHI'ITEMORE.

Titnessesz .To HN F. '3A nnfn'rr, H. G. Barnes.

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