562:What Famous Improvement Cum Invention

______ was invented in Britain in 1822 by Sampson Mordan and Gabriel Riddle. Earliest Morden ______ are thus hallmarked SMGR. Sampson Mordan continued manufacturing ______ and a wide range of silver objects until World War Two, when the factory was bombed.Between 1822 to 1874, more than 160 patents were registered pertaining to a variety of improvements to ______. The first spring-loaded ______ was patented in 1877 and a twist-feed mechanism was developed in 1895. The 0.9 mm lead was introduced in 1938, and later it was followed by 0.7, 0.5, 0.3. Even a 1.4 mm mechanism was available, and 0.4 and 0.2 versions are now produced.The ______ became successful in Japan with some improvements in 1915 by Tokuji Hayakawa, a metal worker who had just finished his apprenticeship. It was introduced as the Ever-Ready Sharp ______. Success was not immediate, since the metal shaft — essential for the ______ long life — was unfamiliar to users. The Ever-Sharp began selling in huge numbers, however, after a company from Yokohama made a large order. Later Tokuji Hayakawa's company got its name from that ______: Sharp.At nearly the same time, in America, Charles R. Keeran was developing a similar ______ that would be the precursor of most of today's ______s. Keeran's design was ratchet-based, whereas Hayakawa's was screw-based. These two development histories are often combined into one.

Ans:Mechanical Pencil