![]() |
|
|
| |
|
||||
Missing image Mechanical_pencil.jpg A ratchet-type mechanical pencil A Mechanical Pencil is a pencil that does not need to be sharpened due to an internal mechanism that pushes graphite through the tip. It was first patented in Britain in 1822 by Sampson Mordan and John Isaac Hawkins. It has also been referred to as a "propelling" pencil due to the way graphite is pushed out through its tip. Most models have a rubber eraser on the end. A number of different types exist:
Most mechanical pencils can be refilled with more graphite but some less-expensive models, especially screw-based designs, are disposable. Mechanical pencils are considered to be more environmentally-friendly than conventional pencils due to the fact that wood is not necessary for its manufacture and no wasteful wood shavings are created.
|
|
|
|
|
|
|
|
Copyright 2008 WordIQ.com - Privacy Policy
::
Terms of Use
:: Contact Us
:: About Us This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Mechanical pencil". |