JP2004066555A - Mechanical pencil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical pencil which can facilitate supplementing of a lead without anxiety of a lead breakage at a lead supplementing time even when a relatively long lead with respect to a length of a barrel is used. <P>SOLUTION: In the mechanical pencil including a barrel 10 containing a lead feeding mechanism 16, a knocking shaft 12 axially movable and separable with respect to the barrel 10 in such a manner that the shaft 12 is axially moved with respect to the barrel 10 to feed the lead L from a tip of the barrel 10, a rear end of a lead tank 20 for constituting the mechanism 16 is projected backward from a rear end opening 10d of the barrel 10, an intermediate barrel 14 for surrounding an outer peripheral surface of a rear part of the tank 20 coupled to an outer peripheral surface of the tank 20 is provided, a distal end of the barrel 14 is inserted from the rear end opening into an annular space between the inner peripheral surface of the barrel 10 and the outer peripheral surface of the tank 20, and the shaft 12 is detachably coupled to the rear part of the barrel 14. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a mechanical pencil.
[0002]
[Prior art]
Conventionally, an outer shaft having a built-in lead-out mechanism and a knock shaft that can be moved and separated in the axial direction with respect to the outer shaft, and the knock shaft is moved in the axial direction with respect to the outer shaft. Thus, there is known a mechanical pencil in which a lead is fed from a tip of an outer shaft. In such a mechanical pencil, by moving the knocking shaft in the axial direction with respect to the outer shaft, that is, by knocking, the center feeding mechanism is operated, and the center is fed by a predetermined amount, and the center is moved from the tip of the outer shaft. Are projected. Also, when the spare core in the core feeding mechanism is lost or running out, the rear end opening of the outer shaft is opened by separating the knock shaft from the outer shaft, and the core is removed from behind. Can be replenished to the lead-out mechanism.
[0003]
[Problems to be solved by the invention]
By the way, in the above-mentioned known mechanical pencil, when a core whose length is relatively long with respect to the length of the outer shaft is used, in other words, the outer shaft whose outer shaft is relatively short with respect to the length of the core is used. When the is used, the entire length of the spare or in-use core will not fit on the outer shaft. In this case, since the rear portion of the core protrudes from the outer shaft, there is a problem that when the knock shaft is separated from the outer shaft, the rear portion of the core is exposed from the outer shaft and the core is broken. .
[0004]
For this reason, the core tank of the core feeding mechanism is extended rearward from the outer shaft, and only the core is exposed so that the core tank containing the core is exposed from the outer shaft without exposing only the core to the rear portion. Can be prevented.
[0005]
However, the outer diameter of the wick tank is smaller than the inner diameter of the outer shaft, and there is play in the radial direction. When the wick moves, the wick cannot be inserted into the wick tank properly, and in some cases, the wick may be caught by the wick tank and the wick may be broken.
[0006]
The present invention has been made in view of such problems, and when using a core having a relatively long length with respect to the length of the outer shaft, there is no need to worry about breaking the core when refilling the core. It is an object of the present invention to provide a mechanical pencil which can be easily performed.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 has an outer shaft having a built-in feed-out mechanism, and a knock shaft movable and separable in the axial direction with respect to the outer shaft. By moving the knocking shaft in the axial direction with respect to the outer shaft, the center feeding mechanism operates, and in a mechanical pencil in which the center is fed from the tip of the outer shaft,
A rear portion of the core tank constituting the core feed-out mechanism is projected rearward from a rear end opening of the outer shaft, and a central shaft connected to the outer peripheral surface of the core tank and surrounding the outer peripheral surface of the rear portion of the core tank is provided. The distal end is inserted between the inner peripheral surface of the outer shaft and the outer peripheral surface of the core tank from the rear end opening of the outer shaft, and the knock shaft is detachably connected to the rear portion of the middle shaft. .
[0008]
Even when the length of the core is longer than the outer shaft, when the knock shaft is separated from the outer shaft, the rear portion of the core tank projects beyond the rear end opening of the outer shaft, Since the central shaft surrounds the outer peripheral surface of the rear portion of the core tank, the core is not independently exposed from the outer shaft, and the core can be prevented from breaking.
[0009]
Furthermore, when the knock shaft is separated from the outer shaft and the core is to be refilled into the core tank, the center shaft with the tip inserted between the inner peripheral surface of the outer shaft and the outer peripheral surface of the core tank is used. Since the wick tank is held and is prevented from inadvertently moving, the wick can be easily refilled into the wick tank.
[0010]
According to a second aspect of the present invention, in the first aspect, the center shaft and the knock shaft are connected to each other so as not to rotate relative to each other, and the tip of the center shaft is inserted so as not to rotate relative to the outer shaft. Features. Thereby, as a result, the relative circumferential position between the knock shaft and the outer shaft can be regulated.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0012]
FIG. 1 is a longitudinal sectional view of a mechanical pencil of the present invention. The mechanical pencil mainly has an outer shaft 10, a knock shaft 12, and a center shaft 14, and a center feeding mechanism 16 is built in the outer shaft 10. As is well known, the lead-out mechanism 16 includes a lead tank 20 for receiving the lead L, a lead-tightening chuck 22 having a rear end press-fitted into the lead tank 20 and tightening the lead L at a front end thereof, A chuck ring 24 on the outer peripheral side of the core tightening chuck 22 for tightening the core tightening chuck 22, a sleeve 26 for restricting the chuck ring 24 from moving backward, and a sleeve 26 and a front end of the core tank 20. A chuck spring 28 that is interposed therebetween and constantly urges the lead tank 20 and the lead fastening chuck 22 backward. The elastic blade portion 26 a formed on the sleeve 26 is locked by the opening 10 a formed on the outer shaft 10, so that the core feeding mechanism 16 is held inside the outer shaft 10.
[0013]
The rear end of the core tank 20 extends beyond the rear end opening 10d of the outer shaft 10 so as to accommodate a core longer than the entire length of the outer shaft 10. The distal end of the center shaft 14 is inserted into the annular space between the inner peripheral surface at the rear part of the outer shaft 10 and the outer peripheral surface at the rear part of the core tank 20, and fits into the annular space.
[0014]
As shown in FIG. 2, a plurality of front ribs 14 a are formed on an outer peripheral surface of a front portion of the center shaft 14 so as to be spaced apart in a circumferential direction, and the front ribs 14 a are formed inside a rear portion of the outer shaft 10. The front portion of the center shaft 14 is inserted into the outer shaft 10 in a state in which the front portion of the center shaft 14 cannot rotate relative to the outer shaft 10 and can move in the axial direction.
Further, a projection 14b is formed on the inner peripheral surface of the front portion of the central shaft 14 slightly behind the portion where the front rib 14a of the central shaft 14 is formed, and a through hole is formed on the peripheral surface. 14c is formed. The projection 14b can be elastically displaced in the radial direction by the through hole 14c. The projection 14b is elastically contacted with the outer peripheral surface of the core tank 20, and the center shaft 14 is pressed into the rear end of the core tank 20, so that the core tank 20 is pressed. Linked to
[0015]
A plurality of rear ribs 14d are formed on the outer peripheral surface of the rear portion of the center shaft 14 so as to be spaced apart in the circumferential direction. The rear ribs 14d are fitted into vertical grooves 12a formed on the rear portion of the knock shaft 12. Therefore, the rear part of the center shaft 14 is in a state in which it cannot rotate relative to the knock shaft 12. Further, a projection 14e projecting outward is formed on the outer peripheral surface of the rear portion of the central shaft 14 slightly ahead of the portion where the rear rib 14d of the central shaft 14 is formed, and a through hole 14f is formed on the peripheral surface. ing. The protrusion 14e is elastically displaceable in the radial direction by the through hole 14f. The protrusion 14e is elastically contacted with the inner peripheral surface of the knock shaft 12, and the center shaft 14 is connected to the knock shaft 12. The coupling force between the central shaft 14 and the knock shaft 12 is set to be weaker than the coupling force between the central shaft 14 and the core tank 20, and the central shaft 14 and the knock shaft 12 are set to be detachable. You.
[0016]
The knock shaft 12 is integrally formed with a clip 12b on its outer surface, and at the rear thereof is formed an eraser receiving portion 12c for receiving the eraser 13.
[0017]
Since the center shaft 14 cannot rotate relative to the outer shaft 10 and the knock shaft 12, respectively, the relative positional relationship between the outer shaft 10 and the knock shaft 12 in the circumferential direction via the center shaft 14 is always a predetermined position. Regulated by relationship. More specifically, a plurality of design portions 10c are formed on the outer peripheral surface of the front portion of the outer shaft 10 at a distance from each other in the circumferential direction (FIG. 4), and the circumferential position of the design portion 10c and the vertical groove are formed. The circumferential position of the front rib 14a of the center shaft 14 and the circumferential position of the rear rib 14d are similarly set to a predetermined relationship. By setting the circumferential position of the vertical groove 12a and the circumferential position of the clip 12b in a predetermined relationship, how the center shaft 14 is connected to the core tank 20 and how the knock shaft 12 is For example, the design portion 10c and the clip 12b can be set so as to be always on the same line even if the design portion 10c is to be connected (FIG. 5).
[0018]
In the mechanical pencil configured as described above, the center shaft 14 projects rearward from the rear end of the outer shaft 10 together with the lead tank 20, and is adapted to the length of the lead L to be accommodated. . Then, in a normal state, the rear portion of the center shaft 14 is inserted into the knock shaft 12, so that the rear portion of the core L extends into the knock shaft 12. In this state, when the knock shaft 12 is moved in the axial direction with respect to the outer shaft 10, that is, when the knock shaft 12 is knocked, the center shaft 14 and the core tank 20 move together with the knock shaft 12 and are connected to the core tank 20. When the knocked chuck 22 moves forward against the urging force of the chuck spring 28 and the knock shaft 12 is released from the knocking force, the chuck 22 returns to its original position. The core L is fed out by a predetermined amount as described above.
[0019]
When it is necessary to refill the core L, the knocking shaft 12 is pulled in the opposite direction to the outer shaft 10 to separate the knocking shaft 12 from the outer shaft 10. Since it is smaller than the coupling force between the core tanks 20, only the knock shaft 12 comes off and the state shown in FIG. 6 is obtained. In this state, the center shaft 14 and the core tank 20 project rearward from the rear end opening 10 d of the outer shaft 10, and even when the core still remains in the core tank 20, The center shaft 14 and the core tank 20 protect the rear part of the core L projecting rearward. Furthermore, the core tank 20 is surrounded by the center shaft 14, and the front portion of the center shaft 14 is inserted into an annular space between the center tank 20 and the outer shaft 10 to serve to hold the center tank 20. In addition, the wick tank 20 does not move carelessly, so that the wick L can be easily refilled into the wick tank 20.
[0020]
When the replenishment of the core L is completed, the knock shaft 12 is connected to the center shaft 14 again. At this time, the front end of the vertical groove 12a formed on the inner peripheral surface of the knock shaft 12 has a tapered shape in which the groove width gradually increases toward the front. Even if the center shaft 14 is inserted into the shaft 12, the rear rib 14d of the center shaft 14 is guided to the depth of the vertical groove 12a by the tapered portion of the vertical groove 12a. Can be combined.
[0021]
【The invention's effect】
As described above, according to the present invention, even when the length of the core is longer than the outer shaft, when the knock shaft is separated from the outer shaft, the core is alone from the outer shaft. It is not exposed, and the core can be prevented from breaking. Further, when refilling the wick tank, the wick tank is held by the middle shaft whose tip is inserted between the inner circumferential surface of the outer shaft and the outer circumferential surface of the wick tank, thereby preventing inadvertent movement. Therefore, the core can be easily refilled into the core tank.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a mechanical pencil of the present invention.
2A is a side view of a center shaft, and FIG. 2B is a longitudinal sectional view of the center shaft.
FIG. 3 is a longitudinal sectional view of a knock shaft.
FIG. 4 is a sectional view taken along line 4-4 in FIG. 1;
FIG. 5 is a plan view of FIG. 1;
FIG. 6 is a longitudinal sectional view showing a state where a knock shaft is removed.
[Explanation of symbols]
Reference Signs List 10 Outer shaft 12 Knock shaft 14 Center shaft 16 Core feed-out mechanism 20 Core tank

Claims (2)

By having an outer shaft with a built-in lead sending mechanism and a knock shaft that is movable and separable in the axial direction with respect to the outer shaft, by moving the knock shaft in the axial direction with respect to the outer shaft In the mechanical pencil where the lead sending mechanism operates and the lead is sent from the tip of the outer shaft,
A rear portion of the core tank constituting the core feed-out mechanism is projected rearward from a rear end opening of the outer shaft, and a central shaft connected to the outer peripheral surface of the core tank and surrounding the outer peripheral surface of the rear portion of the core tank is provided. The distal end is inserted between the inner peripheral surface of the outer shaft and the outer peripheral surface of the core tank from the rear end opening of the outer shaft, and the knock shaft is detachably connected to the rear portion of the middle shaft. mechanical pencil. The mechanical pencil according to claim 1, wherein the center shaft and the knock shaft are connected to each other so as not to rotate relative to each other, and a tip of the center shaft is inserted so as not to rotate relative to the outer shaft.

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