US508704A

US508704A - Blackboard-eraser

Info

Publication number: US508704A
Authority: US
Publication date: 1893-11-14
Anticipated expiration: 1910-11-14

Description

(No Model) J HAGGERTY BLAOKBOARD FRASER.

Patented Nov. 14, 1893.

UNITED ST TES PATENT OFFICE.

JoI-I HAeeERTY, or BRADFORD, PENNSYLVANIA.

BLACKBOARD- ERAS ER.

SPECIFICATION forming part of Letters Patent No. 508,704, dated November 14, 1893.

Application filed-February 25.18%. Serial No.463,664. (No model.

To all whom zit-may concern: 7

zen of the United States,residing at Brad ford, in the county of McKean and State of Pennsylvania, have invented certain new and useful Improvements in Blackboard-Erasers, of which the following is aspecification,reference being had to the accompanying drawings, in which Figure 1 represents a side elevation of my black-board eraser, and shows the erasing stripsinserted transversely to the body. Fig. 2 represents a top view of the same and shows the ends of the erasing strips projecting beyond the body. Fig. 3 represents a side elevation of my black-board eraser in which the erasing strips are inserted lengthwise of the body. Fig. 4. represents an end view of the form shown in Figs. 1 and 2, and Fig. 5 represents an end view of the form shown in Fig. 3.

The object of my invention is to provide a black-board rubber that will readily remove all traces of the chalk from the surface of the I black-board.

1 is the body formed with thelateral finger grooves 2 and end grooves 3 which adapt it to be grasped and firmly held while in use. The eraser is also formed with either the'trans verse grooves 4, or the longitudinal grooves 5, indicated by a dottedline in- Fig. 3 which soft or fibrous material, but I prefer to use felt, it being soft,-yet firm and in wearing retains its angular form.

It will be observed that in Fig. 2 the ends of the erasing strips 6, project beyond the edges of the body 1. It will also be observed that the bottom of the body curves upward at the ends and that the bottoms of the transverse grooves at the ends in Fig. 1 and also the bottoms of the longitudinal grooves 5 in Figs. 3 and 5, are substantially parallel with the under side of the body 1 at those points.

7 Theobject of thus'projecting theends of the Be it known that 1, JOHN HAGGERTY, a citi-,

erasing strips 6 and of so forming grooves is to so dispose the erasing strips that no matter which st rip of my eraser is used, the blackboard will be fully protected from being defaced by contact of the body 1.

In the use of a cloth as an eraser of chalk marks, the cloth does not fully erase, but spreads the chalk in a thin layer over the black-board, necessitating frequent washings of said board in order to clean it. It is well known'that square edges of the eraser assist greatly in the operation by scraping off the chalk. In the use of erasers with a plain flat surface, only that edge toward the direction in which the eraser is moving acts effectively as an eraser, the tendency of the fiat surface being to spread over the board, the chalk not removed by the said edge. But, in my eraser, a series of edges act on the chalk-marksand when in use each edge acts as a scraper and the particles of chalk removed by each,immediately leave the black-board and fall into the recesses between the strips from which they can be dislodged by a gentle knock without raising a dust, and the black-board is thus cleaned of chalk rapidly and effectively.

The erasing strips form angular ribs spaced apart on the face of the body, and inasmuch as they wear evenly in a plane transverse to their body, there are always left the rectangular edges which give efficiency to the article Muse. The end strips are formed with diverging sides and are thus made heavier and stronger than the intermediate strips.

Having thus described my invention, the following is what I claim as new and desire to secure by Letters Patent:

1. A black-board eraser provided with a series of rectangular pieces of felt or similar material formed with plane faces Whose ends project beyond the body of the eraser, as set forth.

2. A black-board eraser provided with a rubbing surface, consisting of a series of transversely secured rectangular strips of feltor' similar material having plane faces in combination with similarly formed end strips of larger transverse sectionthan the main strips as set forth.

3. A black board eraser consisting of a grooved body, strips of felt or similar material secured in the grooves in said body, and 5. The herein describedblack-board eraser a facing of paper or similar protective mateprovided with a body having fiat faces and rial secured to the body of the eraser between beveled ends, a series of rectangular strips se- 15 said strips, as set forth. cured to said flat face and beveled ends and 5 i. The black-board eraser herein described having their rubbing surfaces parallel with consisting of the body provided with grooves said face and ends, all substantially as and cutlgt rigllilt angles to its face, having beveled for the purpose set forth.

en in w ich are cut grooves at right angles A 1 to their faces and rectangular strips of felt or JOHN HAGGLRTY' 10 other material secured in all of said grooves Witnesses:

and having plane erasing faces parallel with AUSTIN '1. HERRICK, the faces of the body, as set forth. BEN. R. HAGAR.