JPH091980A - Mechanical pencil - Google Patents

Abstract

PURPOSE: To prevent impossibility of operation caused by intrusion of a weight body into a stopper provided to a lead tank from being generated though a mechanical pencil is strongly shaked for drawing out the lead by a method wherein the lead tank has an engaging projection, and an intrusion preventive means is provided between the engaging projection and the weight body movably fitted to the lead tank. CONSTITUTION: When a shaft cylinder 1 is shaked in front and in rear for drawing out lead, a weight body 8 built in a lead tank 2 is moved in front and in rear. When the weight body 8 gives strong impact to the lead tank 2 via a closely contact spring being an intrusion preventive means which is provided after an engaging projection 2a of the lead tank 2 in the moving process, a chuck at a tip of the lead tank 2 is advanced, a chuck ring 4 releasably fitted to the chuck abuts against a stage part of a tip tool 9, and a chuck part 3a is opened. When the lead projected from the chuck is retreated under a state wherein it is held by a slider, the chuck is again engaged with the chuck ring 4, and since the chuck part 3a holds the lead by being closed, writing can be carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical pencil for drawing out a lead by utilizing the inertial force of a weight body generated by gripping and shaking a shaft body.

[0002]

2. Description of the Related Art As a mechanical pencil of this type, the one described in Japanese Utility Model Publication No. 58-35513 has been proposed. That is, this conventional example will be described with reference to FIG. 5. In a mechanical pencil in which the lead 22 is gradually fed out by the back and forth movement of a lead tank 27 having a chuck 29 fitted with a tightening ring 26 on the front portion thereof, the lead is gradually removed. An elastic body 31 is attached between the tank 27 and a weight body 30 slidable relative to the lead tank 27.
It is Pupencil.

In order to pay out the core 22, the shaft 21 is moved from B to A.
By swinging in the direction, the front end 30B of the weight body 30 comes into contact with the elastic body 31, the inertial force of the weight body 30 is gently transmitted to the core tank 27, and the core tank 27 resists the elastic force of the chuck spring 28. Move from B to A direction. Therefore, the chuck 29 attached to the lead tank 27 is also fitted with the tightening ring 26, that is, while holding the lead 22, B →
Move in direction A. At this time, the lead 22 moves forward by the holding force of the lead holder 23 built in the base 24.

When the middle component body is further moved in the B → A direction, the tip 26A of the tightening ring 26 abuts against the pre-stage 25C of the groove of the connector 25, and the movement of the tightening ring 26 is stopped, but the chuck 29 further advances. Therefore, the core 22 is released. The front end 27A of the lead tank 27 comes into contact with the rear end 25B of the connector 25 to stop the advance of the middle component body, and at the same time, stop the advance of the weight body 30 while being absorbed by the elastic body 31. Therefore, the repulsive force of the middle component body having the weight body 30 in contact with the connector 25 is weakened, the weight body 30 and the middle component body are retracted by the elastic force of the chuck spring 28, and the chuck 29 is fixed to the tightening ring 26. It is gently pressed and closed to hold the core 22, and the writing state of FIG. 5 is restored.

However, such a conventional mechanical pencil is extremely complicated in structure, and is strong when a stopper such as a protrusion is integrally formed on a core tank made of plastic or the like for the purpose of simplifying the structure. When shaken, the weight body bites into the stopper of the lead tank, and the locking projection provided on the lead tank is damaged, resulting in inoperability.

[0006]

Therefore, the present invention simplifies the structure, and even if it is vigorously shaken for centering, the weight body does not bite into the stopper provided in the core tank and become inoperable. The purpose is to provide a mechanical pencil.

[0007]

To achieve the above object, according to the present invention, there is provided a mechanical pencil having an internal writing shaft body slidably provided in a barrel, the internal writing shaft comprising: A mechanical pencil is provided in which a core tank forming a body has a locking projection, and a biting preventing means is provided between the locking projection and a weight body loosely fitted in the core tank.

Further, according to the present invention, the lead tank slidably provided in the barrel, the chuck press-fitted and fixed in the front end portion of the lead tank, and the chuck ring loosely fitted in the chuck. A sleeve that surrounds the chuck and is provided outside the tip of the lead tank, and is provided between the rear end of the sleeve and the locking projection of the lead tank to bias the lead tank rearward. A chuck spring, a weight body that is movably fitted in the core tank behind the locking projection through a bite prevention means, and a weight body receiving member provided at the rear end of the core tank. The resulting mechanical pencil is obtained.

Further, according to the present invention, the lead tank slidably provided in the barrel, the chuck press-fitted and fixed in the front end portion of the lead tank, and the chuck loosely fitted in the chuck. A ring, a sleeve that surrounds the chuck and is provided on the outer side of the tip of the lead tank, and is provided between the rear end of the sleeve and the locking protrusion of the lead tank to bias the lead tank backward. A chuck spring, a weight body that is movably fitted to the core tank behind the locking projection, and a weight body receiving member provided at a rear end of the core tank. A mechanical pencil is obtained in which the rear end of the locking projection of the lead tank has an upright wall surface that is perpendicular to the axis.

[0010]

[Operation] To perform centering for writing, first, by gripping the shaft cylinder and swinging it back and forth, the weight body incorporated in the core tank moves axially back and forth along the core tank due to inertial force. . During this forward and backward movement process, the weight body exerts a strong impact on the lead tank through the bite prevention means, and this impact causes the chuck spring to move forward against the backward biasing force of the chuck spring. For this reason, the chuck attached to the tip of the lead tank is advanced, and in the process of this advance, the chuck ring loosely fitted to the chuck comes into contact with the step portion inside the tip tool and is released to open the chuck portion.

The core protruding from the chuck is retracted by the action of the chuck spring while being held by the slider and protruding from the tip. In this retreat process, the chuck is again engaged with the chuck ring and the chuck portion is closed to hold the lead, so that writing is possible.

After the writing, the cap can be easily stored by knocking the cap at the rear end to advance the lead tank and the chuck, and lightly pushing the lead tip with the chuck open. The tip of the slider can be easily stored in the tip by gradually releasing the knock cap at the rear end while pressing the tip lightly. The centering is performed by shaking the shaft cylinder, but like the normal knock type mechanical pencil, it is possible to knock the knock cap, that is, the rear end knock, and although not shown. A side knock is also possible.

[0013]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. First, in FIG. 1 to FIG. 3, inside the barrel 1 which forms the main body of the mechanical pencil, the internal writing shaft M
A wick tank 2 accommodating a wick constituting the above is slidably provided. A chuck 3 is provided in the tip of the lead tank 2.
The rear end is press-fitted and fixed. A chuck ring 4 is loosely fitted to the chuck portion 3a at the tip of the chuck 3. A cushion sleeve 5 is provided outside the tip of the lead tank 2 so as to surround the chuck 3.

More specifically, the cushion sleeve 5 is provided with a plurality of notches 5a in the intermediate portion so as to structurally provide a cushioning function in the axial direction so that the core is not broken by excessive writing pressure during writing. In addition, a pair of locking projections 5b are formed on the outside for incorporation with a tip tool described later.

Further, a chuck spring 6 is wound between the rear end of the sleeve 5 and the arcuate locking projection 2a of the lead tank 2 to bias the lead tank 2 rearward. Then, a weight body 8 made of, for example, a metal is movably fitted to the rear of the locking projection 2a via a contact spring 7 as a biting prevention means. That is, the locking protrusion 2a
Is also used as a stopper for the rear end of the chuck spring 6 and the front end of the weight body 8, so that the structure of the mechanical pencil can be simplified. Although not shown, an O-ring made of an elastic material such as rubber may be used instead of the contact spring 7 to achieve the bite prevention function.

Further, a female screw is formed on the inner side of the front end portion of the barrel 1, and a male screw 9a formed on the outer side of the rear portion of the leading member 9 is screwed into the female screw to attach the leading member 9. . A slider 11 having a core pipe 10 at its tip is slidably mounted on the tip of the tip 9 while holding the core. Reference numeral 9b is a guide groove into which the locking projection 5b of the cushion sleeve 5 formed at the rear end of the tip 9 is inserted and fixed. More specifically, this guide groove 9
Since b is formed in an L-shape, the locking protrusion 5b of the cushion sleeve 5 is inserted into the opening of the guide groove 9b to form L.
It can be engaged and fixed by rotating it along the groove.

A clip 12a is attached to the rear end portion of the lead tank 2 via a receiving member 12, and an eraser holder 13 is attached to the holder 13. A cap 14 is attached to and detached from the holder 13 while holding the eraser. It is provided freely.

The operation of the mechanical pencil according to the above embodiment will be described below. To center for writing
First, when the shaft cylinder 1 is grasped and shaken back and forth, the weight body 8 movably incorporated in the core tank 2 is moved by inertial force to the core tank 2
Move back and forth axially along. During this forward and backward movement process, the weight body 8 exerts a strong impact on the lead tank 2 via the contact spring 7 as a biting prevention means, and this impact causes the chuck spring 6 to move forward against the backward biasing force. For this reason, the chuck 3 attached to the tip of the lead tank 2 is advanced, and in the process of this advance, the chuck ring 6 loosely fitted to the chuck 3 comes into contact with the stepped portion of the tip 9 and comes off to open the chuck portion 3a. It

The core projected from the chuck 3 is retracted by the action of the chuck spring 6 while being held by the slider 11 and projected from the tip 11a. In this retreat process, the chuck 3 is again engaged with the chuck ring 4 and the chuck portion 3a is closed to hold the lead, so that writing is possible.

After the writing, the cap 1 at the rear end
The core can be easily stored by lightly pressing the core tip with the chuck 4 advanced and released by knocking the chuck 4. The tip 11a of the slider 11 can be easily housed in the tip 9 by gradually releasing the rear end knock cap 14 while gently pushing the tip. Although the core feed is performed by shaking the shaft cylinder 1, it is also possible to knock the knock cap 14, that is, the rear end knock, as in a normal knock type mechanical pencil.

FIG. 4 is a perspective view of a front portion of a lead tank showing a main portion of a mechanical pencil according to another embodiment. According to this embodiment, a ring-shaped projection 2b for locking is formed on the outer circumference of the lead tank 2. More specifically,
Both front and rear walls of the ring-shaped projection 2b are formed by upright walls 2bb perpendicular to the axis. With the projection 2b having such a shape, the impact of the weight body 8 can be reliably and effectively received on the surface of a relatively large area, and the weight body 8 can be received.
Since it does not bite into the protrusion, it is not necessary to provide the bite prevention means as a separate part.

In this embodiment, it is possible to further incorporate a close contact spring made of metal or the like or an O ring made of rubber or the like as a biting prevention means to give a more effective shock absorbing function. Is.

[0023]

Since the structure of the present invention is as described above, the mechanical pencil has a simple structure and does not become inoperable due to the weight body biting into the stopper even if it is shaken violently. There is an effect that can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a mechanical pencil according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view in which a part of the mechanical pencil of FIG. 1 is omitted.

FIG. 3 is a vertical cross-sectional view showing a usage state of the mechanical pencil of FIG. 1 with a part thereof omitted.

4 is a cross-sectional view of the mechanical pencil of FIG.

FIG. 5 is a vertical cross-sectional view showing a conventional mechanical pencil.

[Explanation of symbols]

 1 Shaft cylinder 2 Core tank 3 Chuck 4 Chuck ring 5 Cushion sleeve 6 Chuck spring 7 Adhesion spring (bite prevention means) 8 Weight body 9 Tip tool 10 Core pipe 11 Slider 12 Receiving member 13 Eraser holder 14 Cap M Internal writing shaft body

Claims (7)

[Claims] 1. A mechanical pencil provided with an internal writing shaft body slidably provided in a barrel, wherein a core tank constituting the internal writing shaft body has a locking projection, and the locking projection is provided. A mechanical pencil characterized in that a biting preventing means is provided between the core and the weight body loosely fitted in the lead tank. 2. A lead tank slidably provided in a barrel, a chuck press-fitted and fixed in a front end portion of the lead tank, a chuck ring loosely fitted in the chuck, and the chuck surrounding the chuck. A sleeve provided outside the tip of the lead tank, a chuck spring provided between the rear end of the sleeve and the locking projection of the lead tank, and biasing the lead tank backward. It is composed of a weight body movably fitted in the core tank behind the locking projection through a biting prevention means, and a weight body receiving member provided at a rear end portion of the core tank. And mechanical pencil. 3. The mechanical pencil according to claim 1, wherein the bite preventing means is a contact spring. 4. The mechanical pencil according to claim 1, wherein the bite preventing means is an elastic O-ring. 5. The mechanical pencil according to claim 1, wherein the locking projections of the lead tank are a pair of arc-shaped projections formed on the lead tank. 6. The mechanical pencil according to claim 1, wherein the locking projection of the lead tank has an upright wall surface whose rear end is perpendicular to the axis. 7. A lead tank slidably provided in a barrel, a chuck press-fitted and fixed in a front end portion of the lead tank, a chuck ring loosely fitted in the chuck, and the chuck surrounding the chuck. A sleeve provided outside the tip of the lead tank, and a chuck spring provided between the rear end of the sleeve and the locking projection of the lead tank to bias the lead tank backward. A weight body movably fitted in the core tank behind the locking projection, and a weight body receiving member provided at the rear end of the core tank; A mechanical pencil having a rear end having an upright wall surface perpendicular to the axis.