US204011A - Improvement in blackboards - Google Patents

Description

H. W. EASTMAN.

Blackboard.

No. 204,011 Patented IVlay 21 ,m mhL. hohl@ MEHR .1w.., .lfwfd *YH ATTUBNEYS. 1

UNITED STATES PATENT OTFI HENRY W. EASTMAN, OF BALTIMORE, MARYLAND, ASSIGN OR TO HIMSELF AND WILLIAMJ. C. DULANY, OF SAME PLACE.

f||v|PRov|aM ENT IN LAcKLao/imns;V

Specification forming part of Letters Patent No. 204,011, dated May 21, 1878; application filed March 16, 1878.

'To all whom t may concerm.

Be it known that I, HENRY W. EASTMAN, of Baltimore city, State of Maryland, have invented a new and useful Improvement in Blackboard; and I do hereby declare that the following is a full, clear, and exact description of the same.

The invention relates to an improvement in that class of blackboards for school use in which the blackboard proper is suspended in a vertical frame in such manner that it may be adjusted at various heights, for convenience of use and observation.

According to my' invention, the blackboard is pivoted in its sliding` frame, which is balanced by a vertically-sliding frame, adapted for holding printed alphabetical tablets or arithmetica-l plates or tablets. The tabletholding frame may be so adjusted as to hold the pivoted blackboard in position-that is to say, prevent it turning on its pivots.

In the accompanying drawing, forming part of this specification, Figure lis afront elevation, and Fig. 2 a vertical section, (one of the hingedtablet-holdingframesbeingrepresented swung open.)

A indicates the blackboard, B the tabletholders, and O the frame, in which said parts A B are arranged to slide in parallel vertical planes.

The side bars of the frame C are grooved to receive projections or ribs on the ends of the blackboard and tablet-holder, so that the two latter are guided vertically Vas they are raised and lowered. The tablet-holder acts as a counterbalance for the blackboard, being connected thereto by means of cords passing over pulleys D D located at the top of the main frame C.

When the blackboard is drawn down the tablet-holder is necessarily raised, and when the tablet-holder is drawn down 'the blackboard is necessarily raised, one balancing the other, and either remaining stationary in any adjustment. Hence the blackboard may be easily drawn down when it is desired to write or draw thereon, and raised again tovexhibit the work. llhe tablet-holder may be similarly operated for the purpose of placing new cards or tablets in its rabbeted frame, and then exposing them plainly to view. When the cards or tablets are in place they are secured by a frame or frames that are hinged to the side bars of the holder B.

The blackboard proper is pivoted centrally at top and bottom a b, so that it may be easily reversed when it is desired to bring the opposite side to the front.

When the tablet-holder C is lowered it prevents the blackboard being reversed or turned on its pivots, las shown in Fig. 2, since the former is then directly behind the latter, and

in contact with it, or nearly so. Thus thel blackboard is kept stationary on its pivots, or prevented from turning thereon when the tablet-holder is lowered into position behindit, but may be quickly reversed when the tabletholder is raised.

In this manner I secure the advantages attending the use of the common pivoted reversible blackboard, and at the same time adapt the board to be adjusted vertically with ease and rapidity, and to be held fixed on its pivf ots'by the same means-to wit, the tabletholder-by which-it is counterbalanced.

As above intimated, I am aware that a vertically-sliding blackboard adapted tobe reversed is not new.

I am also aware that a blackboard pivoted in its frame for reversal, but not capable of

Images