US1989006A - Blackboard - Google Patents

Description

Jan. 22, 1935.

W. B. GARDEN BLACKBOARD Filed Jan. 2, 1954 I a 2 a Fl (3. I. l I F I q. E.

1'71 z/(jh Fl G, W W

Patented Jan. 22, 1935 UNITED STATES PATENT OFFICE Application January 2,

1934, Serial No. 705,003

In Great Britain December 3, 1932 1 Claim.

This invention relates to black-boards and the like of the type comprising an endless band constituted by flexible sheets of surfaced material detachably connected together and trained over top and bottom rollers carried by a frame including spaced uprights.

In connection with such apparatus it has been found that the band at the upper part has a tendency to creep to one side and become jammed against one or other of the uprights of the frame.

The object of the invention is to overcome this objectionable feature by such construction of the uprights that the band at the upper part may be adjusted whereby tendency to jamming is eliminated.

According to the invention, the lower portions of the uprights are disposed vertically and parallel to each other and the upper portions of the uprights are divergently inclined. Desirably the front and rear surfaces of the uprights are fitted with facing strips which present grooves and overlap the side edges of the endless band. The endless band may be constituted by a plurality of sheets of flexible material detachably connected together by plate members folded to present beads which are embraced by a channel-shaped clip member provided with end caps presenting flat end surfaces.

In the accompanying drawing Fig. 1 is an elevation, partly in section, and Figs. 2 and 3 are respectively, a sectional elevation and a sectional plan view of a black-board constructed according to the invention.

As illustrated in Fig. 1, the lower portions 1 of the uprights l, 1' of the black-board are disposed vertically and parallel and the upper portions 1' are divergently inclined.

The front and rear surfaces of the uprights 1, 1' may be provided with facing strips 2 which project inwardly and overlap the edges of the band 3 which wraps the rollers 4.

Desirably the lower parallel portions 1 of the uprights extend to about a height of six feet and the upwardly diverging or downwardly converging up- 5 per portions 1 of said uprights extend about four feet farther, the entire structure being about ten feet high.

As shown by Fig. 1, the side edges 3' of the band are close to the lower. parts 1 of the uprights, while, 10 due to the divergence of the upper portions 1" of the uprights, the said side edges 3 are spaced from said upper portions 1', thereby reducing or eliminating jamming of the band against one or other of the uprights.

Instead of black-board-smfaced material the endless band may carry maps, diagrams or the like.

In adjusting the endless band, as the upper roller is out of reach of persons of normal stature, the pull of the operator will naturally be a downward one on said band, so that the strain falls on the upper roller, and any irregularity in the fabric of the band will naturally cause it to run towards one end or the other of the upper roller. But this tendency to sidewise running of the band is, in the present improved construction, counteracted by the downwardly converging inclined upper parts of the frame uprights.

I claim:

A blackboard including a pair of spaced uprights comprising truly vertical lower portions and divergently inclined upper portions, a horizontal roller extending between said lower portions, a horizontal roller extending between said upper 35 portions and out of reach of persons of normal stature, and a flexible endless band of blackboardsurfaced material trained over said rollers.

WILLIAM BROWNIE GARDEN.

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