who invented the pencil sharpener
When was the Pencil Sharpener invented? The first patent for an invention to sharpen pencils was applied in 1828 by French mathematician Bernard Lassimone. The improved mechanical sharpener was invented in 1847 by Therry des Estwaux. In 1855 Walter K. Foster patented the first American pencil sharpener. Since 1917 the electric pencil sharpeners have been made for the office use..