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Mechanical pencil with refill indicator

IP.com Disclosure Number: IPCOM000004405D
Publication Date: 2000-Nov-08
Document File: 1 page(s) / 19K

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention is a mechanical pencil including a cartridge tube having one end open, lead color A within the tube, and lead color B seamlessly attached to lead color A, a lead grip mounted in cartridge tube holding the pencil lead in place, and a spring loader that pushes the lead down the cartridge tube during use. Lead color A and lead color B are of two distinct colors.

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Mechanical pencil with refill indicator

One of the most ubiquitous writing implements in use is the mechanical pencil. Many millions of such devices are produced each year. There is a significant market for both original and refill leads for mechanical pencils.

Mechanical pencils often provide no means of showing the amount of lead remaining in a cartridge. This is particularly true of pencils that use an opaque barrel or housing. What is needed is a way for the user of a mechanical pencil to know when the pencil is nearly empty.

Figure 1 Diagram of mechanical pencil with low-lead indication

The present invention is a mechanical pencil including a cartridge tube 110 having one end open, lead color A 120 within the tube, and lead color B 130 seamlessly attached to lead color A 120, a lead grip 140 mounted in cartridge tube 110 holding the pencil lead in place, and a spring loader 150 that pushes the lead down the cartridge tube during use. Lead color A 120 and lead color B 130 are of two distinct colors. For example, lead color A 120 might be black, and lead color B 130 might be blue. During the normal life of the mechanical pencil, writing will appear in the color of lead color A 120. Near the end of the life of the lead, the color of writing produced by the lead will change to lead color B 130, indicating it is time to replace the lead. In the example, the lead would be provided and labeled as a black lead replacement. Near the end of its useful life, however, the writing produced by the mechanical pencil will turn from black to blue. This indicates to the user that it is time to replace the lead, though the pencil will continue to function for some period of time related to the amount of lead color B 130 remaining in cartridge tube 110.