A. H. KEMPEN. FRASER FOR BLAGKBOARDS; N0. 303,521. Patented Aug. 12, 1884..
WITNE 5 SEE! NITED STATES PATENT Prion.
ADOLPI-I H. KEMPEN, OF AUSTIN, TEXAS.
ERASER FOR BLACKBOARDS.
SPECIFICATION forming part of Letters Patent No. 303,521, dated August 12, 1884.
Application filed May 16, 1884. (No model.)
To all whom it may concern:
Be it known that I, ADOLPH H. KEMPEN, a citizen of the United States, residing at Austin, in the county of Travis and State of Texas, have invented certain new and useful Improvements in Blackboard-Erasers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.
My invention is an improvement in devices for rubbing chalk-marks from a blackboard or slates, known in the trade by the name of erasers. It is composed of a block fashioned out of any suitable material-wood preferred-with a suitable handle, and prm'ided with a base having a bed rounding in shape,
provided with a rabbet following its edge, one
side of which is beveled and the other plain, the two sides of said rabbet forming an obtuse angle about the entire perimeter of the said block. I use as a rubbing-surface a pad or piece of Brussels carpet, by preference, although I do not wish to confine myself to this or any other particular fabric for this purpose. The eraser 'is provided with a ring, preferably of metal, having the general conformation of the bed portion of the block, so formed, as seen in transverse section, as to fit loosely upon the rabbet on the edge of the block. The rubber is held to place on its bed by the ring aforesaid, which latter is itself fixed to place in the block by pins which pass through said ring and into said block.
I11 my drawings, Figure 1 is a bottom or face view of the eraser. Fig. 2 is an elevation of the eraser complete. Fig. 3is atransverse section of the same.
Similar reference-letters indicate like parts in all of the figures.
Referring to the drawings, A is the block, preferably elliptical in form, provided with a knob, A, and a bed portion, B.
G is an annular rabbet of obtuse angular form, which follows the edge of the bed portion B and merges by a rounded edge into the bearing-surfitce of the block.
D is a metallic ringfor holding the pad E to place upon its bed. JA transverse section of this ring shows it to be in conformity with the rabbet O, which follows the edge of the block, the diameters of said ring being, however, greater than the said rabbet to allow of the interposition of the pad E between it and the said rabbet C. The pad E,which is placed upon its bed on the block, is stretched slightly and turned down upon the surrounding rabbet of the block. The metallic ring is forced down over the turned edge of the pad until the latter is smoothly stretched upon its bed, when the said ring is secured to position by pins a c, which are driven into the block. The pad, it may be observed, is clamped firmly by the portion 6 of the ring, which holds the said pad tighter as it is pushed farther onto its place.
It will readily be seen that the pad, when worn or overloaded with chalk and dirt, may be easily displaced and a new one substituted.
It is obvious that the only wear to the eraser during use is to the pad, and this may be replaced with but trifling expense and trouble.
I am aware of the patent to WValker, No. 59,933, which shows a grooved block, upon which a pad is clamped by means of a wire,
which forces the edges of said pad into the groove, and to such I make no claim.
I am also aware of thepatent of Ramage, No. 277,341, which shows a block provided with a rectangular rabbet and a wire adapted to fit over said rabbet and hold a pad to position, and to such I make no claim. I
I am also aware that erasers are in use hav ing pads of corduroy and other ribbed goods, which is secured permanently to blocks by means of tacks, nails, Ste, but to such I make no claim.
Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-- 1. The eraser; composed of the block A,