Running Head: TECHNICAL DESCRIPTION

 

 

 

 

 

 

 

Technical Description of a Mechanical Pencil

Afsana Akter

The City College of New York

 

 

 

 

 

 

 

 

 

 

TECHNICAL DESCRIPTION OF A MECHANICAL PENCIL

OUTLINE OF THE CONTENTS

                                    Page

Title page ………………………………………………………………………………………. 1

Outline of the Contents …………………………………………………………………………. 2

Introduction …………………………………………………………………………………… 3

Body …………………………………………………………………………………………… 3-8

1 The Mechanical Pencil ………………………………………………………………….. 3-4

1.1 Description of Main Parts …………………………………………………………. 4

1.2 Gripping Assembly ……………………………………………………………….. 4-5

1.2.1 Rubber-Gripping Barrel …………………………………………………………. 5

1.2.2 Cone Cap ……………………………………………………………………… 5-6

1.2.3 The Lead Rod Outlet …………………………………………………………… 6

1.2 Barrel Assembly ………………………………………………………………….. 6-8

Conclusion …………………………………………………………………………………… 8

References ……………………………………………………………………………………. 9

 

 

 

 

 

 

 

TECHNICAL DESCRIPTION OF A MECHANICAL PENCIL

Introduction

The Mechanical Pencil is a mechanical writing instrument that uses erasable lead rods to draw or write text, designs, and symbols on mediums such as paper and wood. The Mechanical Pencil is most commonly used for drawing pictures and writing text on paper. In the United States it is also known as “propelling pencil.” The first, Mechanical Pencil was invented in 1565 by Conrad Gesner, a Swiss naturalist, and bibliographer (“Inventor of Mechanism,” n.d.) He invented a lead holder pencil, which had to be manually adjusted so it could be sharpened. The first Mechanical Pencil which had a propelling system was invented by Sampson Mordan and John Isaac Hawkins in Britain in 1822 (“Inventor of Mechanism,” n.d.) Mordan decided to start manufacturing mechanical pencils alone in his “S.Mordan & Co.” company (“Inventor of Mechanism,” n.d.) Later he continued to make mechanical pencils until the Second World War when his factory was destroyed by the bombing. After his invention others tried to improve the mechanism of the mechanical pencil. The Mechanical Pencil can be held in the palm of a hand. Today mechanical pencil is very popular among students, as it is convenient to use without sharpening.

1. The Mechanical Pencil

The above image has been labelled after watching a youtube video (Firmin, 2016). The cone cap (Figure 1), located at the bottom, provides a pointed opening where lead rods can be ejected for writing. The pocket clamp holder (Figure 1), located at the top, can clamp around T-shirt’s pockets allowing for hands-free carrying and easy access. The eraser (Figure 1), inserted at the top, can erase lead particles from paper, wood or other mediums where it has been applied. The eraser (Figure 1), can also be removed allowing it to be replaced.

1.1 Description of Main Parts

The Mechanical Pencil (Figure 2) consists of two main components:

1) the gripping assembly

2) the barrel assembly

Figure 2: Main Components of the Mechanical Pencil

1.2 Gripping Assembly

The gripping assembly (Figure 3) is a hollow rubber and chrome casing designed to protect the internal mechanisms and to hold the lead rods. The rubber casing is a finger grip used to hold the mechanical pencil while writing. The gripping assembly is attached to the barrel assembly.

The gripping assembly consists of three main components:

1) the rubber-gripping barrel

2) the cone cap

3) the lead rod outlet

Figure 3: The Gripping Assembly

1.2.1 Rubber-Gripping Barrel                                                   

The rubber-gripping barrel (Figure 4), grey colored, is a holding device used to hold the Mechanical Pencil between the thumb, index finger and middle finger while writing or drawing. The rubber gripping barrel wraps around the hourglass barrel and tapers in at the middle which allows it to grip the bottom middle finger joint. It has a ribbed casing to enhance gripping performance and it is made of soft grey rubber designed for comfortable gripping during prolonged periods of use.

Figure 4: Rubber-Gripping Barrel

1.2.2 Cone Cap

The cone cap (Figure 5), teal colored, is a hollowed cast casing designed to protect the mechanical lead rod holder located inside, and to align the lead rods with the lead rod outlet. The cone cap is made of hi-impact plastic, and is attached to the grey colored hourglass barrel.

Figure 5: Cone Cap

1.2.3 The Lead Rod Outlet

The lead rod outlet (Figure 6) is a hollowed cast casing designed to wrap around the lead rods. The lead rod outlet strengthens the lead rods and prevents them from breaking while writing. The lead rod outlet is made of hi-impact plastic and is connected to a teal colored plastic fitting with the cone cap.

Figure 5: The Lead Rod Outlet

1.2 Barrel Assembly

The barrel assembly (Figure 7) is a hollow grey colored plastic casing designed to protect the internal mechanisms and to hold the lead rods and eraser. The barrel assembly is also fitted with a pocket clamp holder. The barrel assembly rests on the index finger, helps balance the Mechanical Pencil while writing, and is attached to the gripping barrel.

The barrel assembly consists of four main components:

1) the hourglass barrel

2) the pocket clamp holder

3) the lead rod ejector

4) the eraser

The hourglass barrel (Figure 7) is a hollowed cast casing designed to store the lead rods and to balance the Mechanical Pencil on the index finger.

Figure 7: Barrel Assembly

The pocket clamp holder (Figure 8) is a fastening device designed to carry the Mechanical Pencil by clamping around T-shirt breast pockets. The Mechanical Pencil clamps around T-shirt pockets by sliding between the hourglass barrel and the flexible plastic clamp. The Mechanical Pencil clamps around T-shirt pockets by sliding between the hourglass barrel. The pocket clamp holder is made of high-impact teal colored plastic. The lead rod ejector (Figure 8) is a retracting button used to hold the removable eraser and to eject the lead rods through the lead rod which is located at the bottom of the Mechanical Pencil. The lead rod ejector is made of teal colored hi-impact plastic and internally connected to the hourglass barrel. The eraser (Figure 8) is a cylindrical rubber plug that fits into the lead rod ejector opening and is used to remove lead particles on paper. The removable eraser is made of white rubber.

Figure 8: Barrel Assembly

Conclusion

The Mechanical Pencil is a writing instrument which is easy to use. Its look like a pen but the lead works as a pencil which is erasable and more convenient to use. It is inexpensive and it is available in different stores, including the store staples, which is very popular among students in need of school supplies. Some mechanical pencils also have a removable eraser and lead, which allows it to be reused. Mechanical pencil does not have the limitations of traditional lead and wood pencils, that is why it has a good feature to reuse.

References

History of the Mechanical Pencil – Inventor of Mechanism. (n.d.). Retrieved from http://www.historyofpencils.com/writing-instruments-history/history-of-mechanical-pencils/

Firmin, K. (2016, June 05). Retrieved November 12, 2018, from https://www.youtube.com/watch?v=rVgShcj2RTo