JP2009126169A - Mechanical pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical pencil which enables an eraser to be easily detached from a main barrel and can be substantially used in a favorable usability in the same manner as that of a single eraser, and further which enables the need to be eliminated for changing handling of the main barrel to a state of being turned bottom up. <P>SOLUTION: The mechanical pencil comprises in which a knocking operation cylinder body 3 for performing the knocking operation of a lead feeding mechanism built in the main barrel 2 is detachably mounted in the radial direction of the main barrel 2 in the rear end 2a of the main barrel 2 and get the knocking operation cylinder body 3 filled with the eraser 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a mechanical pencil provided with an eraser, and more particularly, to a mechanical pencil in which an eraser can be easily removed from a main body shaft and can be used with substantially the same ease of use as a single eraser. .

With the mechanical pencil, the lead feeding mechanism built into the main shaft is operated by knocking the knock cap that protrudes from the rear end of the main shaft. When erasing after writing, the eraser is removed by removing the knock cap covered with the eraser stored in the body shaft, and the eraser is exposed, and the body shaft is moved upside down to perform the erasing work. Is common (see Patent Document 1).

Further, at the rear end of the main body shaft, an eraser feed shaft tube portion is provided, and the eraser feed shaft tube portion is held with an eraser, and the eraser feed shaft tube portion is relatively rotated together with the main body shaft, It is also known that the eraser is made to appear and disappear from the eraser feeding shaft tube portion, and the erasing operation after writing is performed by moving the main body shaft upside down (see Patent Document 2).

However, the erasing operation in each of the above-mentioned patent documents is performed by changing the main shaft of the mechanical pencil upside down after removing the knock cap or after feeding out the eraser from the eraser feeding shaft tube portion. It can be easily removed and cannot be used in a state of use substantially similar to a single eraser, and the ease of use of the eraser is poor.

Moreover, in the thing of patent document 1, since the eraser put on a knock cap is inserted in the opening end of the lead tank which comprises a lead feeding mechanism via the eraser holder, the diameter of the eraser is thin. In addition to being easy to break, it cannot be lengthened, and in order to prevent breakage, there is a problem that the eraser material needs to be hardened and the erasability tends to be low.
JP-A-2005-231148 Japanese Patent Laid-Open No. 2002-362088

In view of the present situation, the present invention can be easily removed from the main shaft and used in the same manner as a single eraser with good usability. An object of the present invention is to provide a mechanical pencil that does not need to be changed upside down.

As described in each claim in “Claims”, the above-described problem is solved by the invention having the following configuration.

(1) At the rear end of the main body shaft, a knock operation cylinder for knocking a core feeding mechanism built in the main body shaft is detachably mounted in the radial direction of the main body shaft, and the knock operation cylinder body Load the eraser with.

(2) In the above item (1), the peripheral wall at the rear end of the main body shaft is partially cut out, and the knock operation cylinder is detachably attached to the main body shaft through the notch, and the knock operation cylinder is mounted. The peripheral side wall complements the peripheral side wall of the main body shaft at the notch.

(3) In the above item (2), the eraser is attached to the knock operation cylinder so as to be fed out.

(4) In the above item (3), as means for attaching the eraser to the knock operation cylinder so as to be able to be fed out, the knock operation cylinder is provided with an outer cylinder shaft portion stored at the rear end in the main body shaft, An inner cylinder shaft portion that is rotatably fitted in the cylinder shaft portion, and an eraser holder that is slidably assembled in the axial direction within the inner cylinder shaft portion and that holds one end of the eraser, and By rotating the knock cap fitted to the rear end of the inner cylinder shaft part, the outer cylinder shaft part and the inner cylinder shaft part can be rotated relative to each other, and the protrusion formed on the outer peripheral part of the eraser holder is By engaging the spiral groove formed on the inner peripheral surface of the outer cylinder shaft part via the guide groove formed along the axial direction of the inner cylinder shaft part, and moving the eraser holder in the axial direction , Eraser should be sent out so that it can appear and disappear.

According to the present invention, the following effects can be obtained.
According to the first aspect of the present invention, the knock operation cylinder for knocking the core feeding mechanism built in the main body shaft is detachably attached to the rear end of the main body shaft in the radial direction of the main body shaft. At the same time, since the eraser is loaded in the knock operation cylinder, the eraser can be easily removed from the main shaft when the knock operation cylinder is removed, and the eraser loaded in the knock operation cylinder is gripped by the knock cylinder. It can be used with the same ease of use as a single eraser, and there is no need to change the body shaft upside down during the erase operation.

According to the second aspect of the present invention, the peripheral wall at the rear end of the main body shaft is partially cut out, and the knock operation cylinder is detachably attached to the main body shaft through the notch, and the knock operation cylinder is mounted. Since the peripheral side wall of the main body shaft complements the peripheral side wall of the main body shaft at the cutout portion, the knock operation cylinder can be easily removed in the radial direction of the main body shaft, and the design is achieved by complementing the peripheral side wall of the main body shaft. The effect can be enhanced.

According to the invention described in claim 3, since it can be used by being properly extended according to consumption of the eraser, it is easy to use.

According to the fourth aspect of the present invention, the eraser can be easily fed out after being detached from the main body shaft.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a front view showing an overall configuration of a mechanical pencil according to an embodiment of the present invention, FIG. 2 is an enlarged longitudinal sectional view of a main part near the rear end of a main body shaft, and FIG. 3 is a part of a knock operation cylinder. FIG. 4 is an exploded perspective view showing, in an enlarged manner, a state where the knock operation cylinder body is detached from the main body shaft.

As shown in FIG. 1, the mechanical pencil 1 of the present invention includes a knock operation cylinder 3 loaded on the rear end 2 a of the main body shaft 2 and an eraser 4 loaded on the knock operation cylinder 3.

As shown in FIGS. 2 and 3, the knock operation cylinder 3 is rotatably fitted into the outer cylinder shaft portion 5 stored in the rear end 2 a in the main body shaft 2 and the outer cylinder shaft portion 5. The inner cylinder shaft portion 6 and the eraser holder 7 that is slidably assembled in the axial direction in the inner cylinder shaft portion 6 and holds one end of the eraser 4 constitute an eraser feeding mechanism.

A knock cap 8 is fitted to the rear end 6a of the inner cylinder shaft portion 6, and the inner cylinder shaft portion 6 is rotated by the rotation of the knock cap 8, so that the outer cylinder shaft portion 5 and the inner cylinder are rotated. The shaft portion 6 is rotatable relative to each other.

A protrusion 9 is formed on the outer peripheral portion of the eraser holder 7, and the protrusion 9 is formed inside the outer cylinder shaft portion 5 via a guide groove 10 formed along the axial direction of the inner cylinder shaft portion 6. By engaging the spiral groove 11 formed on the peripheral surface, the eraser holder 7 is axially moved along with the relative rotation of the outer cylinder shaft portion 5 and the inner cylinder shaft portion 6 due to the rotation of the knock cap 8. So that the eraser 4 can be extended and retracted.

An overhang engaging portion 12 is formed along the axial direction on the outer peripheral side surface of the outer cylinder shaft portion 5, and the overhang engaging portion 12 is formed on the peripheral side wall of the main body shaft 2 as shown in FIG. 4. The outer cylinder shaft portion 5 is elastically held in the shaft tube of the main body shaft 2 in a notch portion 13 formed by cutting a part in the axial direction with a width smaller than the radius of the shaft tube. By engaging with the main shaft 2 from the radial direction, the knock operation cylinder 3 is mounted so as to be slidable in the axial direction so that the knock operation is possible, and detachable from the radial direction of the main shaft 2. .
Further, the knock operation cylinder 3 is detachably assembled at the cutout portion 13 so that the peripheral side wall of the overhanging engagement portion 12 can complement the peripheral side wall of the main body shaft 2.

The front end of the outer cylinder shaft portion 5 in the knock operation cylinder 3 abuts on the open end 14a of the core tank 14 constituting the core feeding mechanism, and is linked to the knock operation of the knock operation cylinder 3 via the core tank 14. The lead feeding mechanism is activated.

By the operation of the lead feeding mechanism, the pencil lead 15 appears and disappears from the front end 2b of the main body shaft 2.

In addition, when the knock operation cylinder 3 is mounted on the main body shaft 2, the front end of the inner cylinder shaft portion 6 is located in the opening end 14 a at the rear end of the core tank 14 together with the front end of the eraser 4 as shown in FIG. 2. As a result, when the knock operation cylinder 3 is mounted in the main body shaft 2 after erasing, the front end of the eraser 4 can be accommodated with the front end protruding. Even if it is not completely accommodated, the knock operation cylinder 3 can be mounted in the main body shaft 2, and the front end of the eraser 4 can be prevented from being exposed to the outside.

It is a front view which shows the whole structure of the mechanical pencil of one Embodiment in this invention. It is a principal part expansion longitudinal cross-sectional view in the rear-end vicinity of a main-body axis | shaft. It is an expansion perspective view which shows a knock operation cylinder partly fractured, and shows. It is a disassembled perspective view which expands and shows the removal state of the knock operation cylinder body from a main body axis | shaft.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mechanical pencil 2 Main body axis | shaft 2a Rear end 2b Front end 3 Knock operation cylinder 4 Eraser 5 Outer cylinder shaft part 6 Inner cylinder shaft part 6a Rear end 7 Eraser holder 8 Knock cap 9 Projection 10 Guide groove 11 Spiral groove 12 Overhang engaging part 13 Notch 14 Core tank (Core feeding mechanism)
14a Open end 15 Pencil lead

Claims (4)

At the rear end of the main body shaft, a knock operation cylinder for knocking the core feeding mechanism built in the main body shaft is detachably mounted in the radial direction of the main body shaft, and an eraser is attached to the knock operation cylinder. A mechanical pencil characterized by being loaded. A part of the peripheral side wall at the rear end of the main body shaft is notched, and the knock operation cylinder is detachably attached to the main body shaft through the notch, and the peripheral wall of the knock operation cylinder is at the notch, The mechanical pencil according to claim 1, wherein the peripheral side wall of the main body shaft is complemented. The mechanical pencil according to claim 1 or 2, wherein an eraser is attached to the knock operation cylinder so as to be fed out. As a means to attach the eraser to the knock operation cylinder so as to be able to be fed out, the knock operation cylinder is inserted into the outer cylinder shaft part stored at the rear end in the main body shaft and rotatably inserted into the outer cylinder shaft part. And an eraser holder that is slidably assembled in the axial direction within the inner cylinder shaft portion and that holds one end of the eraser, and is fitted to the rear end of the inner cylinder shaft portion. By rotating the knock cap, the outer cylindrical shaft portion and the inner cylindrical shaft portion can be rotated relative to each other, and the protrusion formed on the outer peripheral portion of the eraser holder extends along the axial direction of the inner cylindrical shaft portion. By engaging the spiral groove formed on the inner peripheral surface of the outer cylinder shaft portion through the guide groove formed in this manner and moving the eraser holder in the axial direction, the eraser can be extended and retracted. The mechanical pencil according to claim 3.

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