US402925A

US402925A - Blackboard-eraser

Info

Publication number: US402925A
Authority: US
Publication date: 1889-05-07
Anticipated expiration: 1906-05-07

Description

' (No-Model.)

' F. HAMMER.

BLAGKBOARD BRASER. v N0. 402,925 Patented May 7, 1889.

Y llamarn/s) v. m U

.by the hand when the eraser is used.

UNITED STATES PATENT OEEIcE.

FRANK HAMMER, OF SENECA FALLS, NEI/V YORK.

BLACKBOARD-ERASER.

SPECIFICATION forming part of Letters Patent No. 402,925, dated May 7, 1889.

Application filed .T une 26, 1888. Serial No. 278,232. (No inodel.)

To @ZZ whom, it may concern.-

Be it known that I, FRANK HAMMER, of Seneca Falls, in the county of Seneca and State of New York, have invented anew and useful Improvement in Blackboard-Erasers, which improvement is fully set forth in the following specification, and shown in the accompanying drawings.

The object of my invention is to produce an improved eraser for blackboards, the invention being hereinafter fully described, and more particularly pointed out in the claim. This eraser is formed with a block or body, substantially of common form, to which to secure the erasing material, the block being grasped The erasing material may be of any soft yielding substance; but I prefer a woolen orother fabric, formed and secured to the block in a novel manner to better erase the chalk from the blackboard and hold the dust.

Referring to the drawings, Figure l is a sectional view of the eraser, taken on the dotted line in Fig. 2; Fig. 2, a side elevation of the device in part longitudinally sectioned on the line y in Fig. l, and Fig. 3 a transverse section on the line z in Fig. l.

Referring to the parts of the device, A is the block or body of wood suitably formed having a flat uncut surface, k, forming a-seat for the erasing material, b. The body of the erasing material, b, is made in strips or bands of uniform width and thickness, three of which strips being placed evenly side by side and in contact, as shown, having their edges secured to the face of the block by glue or other adhesive substance. l These strips before they are glued on are doubled or folded to a serpentine form, as shown, extending from side to side of the block, leaving transverse channels or spaces d between the folds formed to catch and hold the chalk-dust. Triangular pockets care also formed at the circular ends of the folds for receiving the chalk-dust.

A band, a, preferably of erasing material, is secured to the periphery of the block, extending longitudinally therearound in position to inclose the erasing material, b. This band extends upward from the face of .the block, so as to have its free edge even with or in the plane of the free edges of the erasing-strips, so as with them to bear against the surface of the blackboard. As shown, the band is tangent to the curved ends of the erasingstrips and completes the triangular pockets c.

As shown in Fig. 2, the erasing-strips adjacent to the channels d are formed to sub` stantially bendv toward each other at their .free edges, so as to close over the channels,

thus serving to inclose and hold the chalkdust entering the channels. Each channel opens at its end into a triangular pocket, c, on account of which the channels may be cleared of the dust at any time by tapping the block edge downward, first in one direction and then in the other. The dust falling into the pockets c may be removed by turning the eraser face downward. The channels open alternately into the pockets c, one in one direction and the next in the other direction.

Of course more or fewer strips than three of the erasing material may be employed, three being shown only as being a convenient number.

What I claim as my invention is- A blackboard-eraser consisting of a block having strips of erasing material placed side by side and in contact, secured in continuous folds extending across its face, forming alternate curves or bends at the sides of the block, and a band secured to the periphery of the block tangent to the bends of the strips, forming therewith a series of triangular pockets, and transverse channels between the folds of the strips opening in alternate directions into said pockets, the strips adjacent to the channels bending at their free edges over the channels, substantially as shown.

FRANK HAMMER.

Witnesses:

JoHgN L. RAYMOND, WILLIAM HILLs.