US647013A - Blackboard-rubber. - Google Patents

Description

' No. 647,0l3. Patented Apr. "1.1900. J. G. MEGREDY. BLACKBOAB'D RUBBER.

(Appli cation fl1ed May 9, 1899.)

(No Model.)

INVENTDR.

WITNESSES NITED STATES PATENT OFFICE.

JOHN G. MEOREDY, OF SAN FRANCISCO, CALIFORNIA.

BLACKBOARD-RUBBER.

QPEGIFICATION forming part of Letters Patent No. 647,013, dated April 10, 1900. Applioation file d May 9, 1899. $eria1No.716,152. (No model.)

To all whom, it may concern:

Be it known that I, JOHN G. MEOREDY, a citizen of the United States, residing at the city and county of San Francisco, in the State of California, have invented certain new and useful Improvements in Blackboard-Rubbers; and I do hereby declare the following to be a full, clear, and exact description of said invention, such as will enable others skilled in the art to which it most nearly appertains to make, use, and practice the same.

The object of my invention is to provide a rubber for removing chalk-marks from blackboards in which the chalk-dust which is removed from the surface of the board by the rubber will be caught and conducted into a hollow interior of the brush or rubber, and thereby be prevented from falling to the floor or distributing itself on the clothing of the person handling the rubber.

It consists, first, in making the interior of the brush hollow, and, secondly, in providing numerous angular holes leading from the rubbing-surface of the brush or rubber to this hollow interior, and also in providing a trap-compartment in the lower end of the hollow interior and a means for removing the accumulated chalk-dust therefrom, all as hereinafter more fully describe Referring to the accompanying drawings, Figure 1 is a perspective view of the brush, showing the perforated rubbing surface. Fig. 2 is a longitudinal section. Fig. 3 is a back view showing a portion of the back and one edge broken away to show the interior construction. 7

Let A represent a shallow box, which may be made of wood, sheet metal, or other suitable substance and covered on all sides and ends with a thick layer of felt B, or the entire rubber may be made of felt or other soft elastic material and formed with an interior cavity or chamber 0. A very satisfactory hollow brush or rubber could be made of a light wire framework covered with felt or other textile covering and would be very elastic and noiseless.

The front or rubbing surface of this brush I make with numerous holes e 6, leading through the rubbing-surface and communicating with the hollow interior or chamber, so that as the rubber passes over the blackboard-surface the detached chalk-dust will enter these holes and pass to the interior chamber instead of falling upon the floor or floating in the atmosphere. I prefer to make these holes diagonal to the rubbing-surface in one direction, or one half of the rubbingsurface may have the holes diagonal in one direction and the other half diagonal in the opposite direction. In the drawings I have shown them diagonal in only one direction and extending to within a short distance of the end toward which they pitch; but this imperforate end F recedes sharply from the lowermost 'row of holes, so that it will not touch the blackboard-surface when the rubber is being used. The object of thisimperforate end is to form an imperforate side to the dust-box G inside the rubber, where the dust accumulates, and it also serves to indicate to the user which is the top of the rubber, so that in using it he will not get the dust chamber at the top.

In the drawings I have shown a thin sheetmetal front to the box, with felt covering it. This sheet-metal front h has transverse lines of narrow slits i, which are formed by punching long holes through it and bending the lip thus formed inward. The holesin the felt covering are arranged to fit over these slits '5, so that the chalk-dust will pass from the diagonal holes into and through the slits and fall into the interior chamber.

The dust-box G is separated from the main chamber 0 by an inclined partition L, which extends across the chamber from the front to near the back, leaving a narrow space 0 between its lower end and the back of the chamber, through which the dust can pass into the dust-box. An opening P in the side of the chamber is closed by a plug, which, being removed, allows the dust to be removed from the chamber.

Having thus described my invention, what a thick layer of I claim, and desire to secure by Letters Patfor removing the dust from said dust-chament, is her, substantially as described. 10

In a blackboard-rubber having an interior In witness whereof I have hereunto set my chamber and holes leading through the rubhand this 18th day of April, 1899.

5 bing-surface and communicating with the in- JOHN G. MEOREDY.

terior chamber; a dust-chamber at one end Witnesses: of said brush separated from the main cham- CHAS. J. ARMBRUSTER,

her by an inclined partition, and an opening J. A. BAYLESS.

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