JP2023136459A - Core holding device and mechanical pencil provided with the core holding device - Google Patents

Abstract

To hold a shorter core firmly.SOLUTION: A core holding device 30 includes: a cylindrical core holding holder 31 through which a core X is inserted and guided forward; and an outer cylinder 32 that covers an outer peripheral surface of the core holding holder 31. On a front end side of the core holding holder 31, there are provided a core holding portion 31b whose inner peripheral surface is gradually reduced in diameter toward the front so as to hold an outer peripheral surface of the core X, and a notch portion 31d that separates the core holding portion 31b in a circumferential direction.SELECTED DRAWING: Figure 5

Description

The present invention relates to a lead holding device that holds a lead to be inserted from the outer peripheral side thereof, and a mechanical pencil equipped with this lead holding device.

Conventionally, mechanical pencils, as described in Patent Document 1, for example, include a guide tube in a portion at the front end of which the lead is sent out, through which the lead is inserted and guided forward.
According to this prior art, when a core is broken, for example, it is possible to hold the rear end of the broken core in the guide tube and to make the front end protrude from the guide tube.

JP2001-180181

However, according to the prior art, the holding force of the guide tube against the folded core is weak, so that the folded core may rotate when attempting to write. Furthermore, if the bent core is too short, there is a risk that it will easily come off from the guide tube.

In view of such problems, the present invention includes the following configuration.
It includes a cylindrical lead holding holder through which the lead is inserted and guided forward, and an outer cylinder that covers the outer peripheral surface of the lead holding holder, and a front end side of the lead holding holder is configured to hold the outer peripheral surface of the lead. A lead holding device comprising: a lead holding part whose inner circumferential surface is gradually reduced in diameter toward the front; and a cut part separating the lead holding part in the circumferential direction.

Since the present invention is configured as described above, it is possible to firmly hold a shorter lead.

1 is a side view showing a mechanical pencil equipped with an example of a lead holding device according to the present invention. FIG. 3 is an exploded perspective view of the concentric holding device. FIG. 2 is an enlarged vertical cross-sectional view of a main part of the concentric holding device. FIG. 3 is a longitudinal cross-sectional view showing a state in which the core is inserted into the concentric holding device. It is a longitudinal cross-sectional view showing a state in which the leading core and the trailing core are inserted into the concentric holding device. FIG. 7 is a perspective view showing another example of the lead holding holder. FIG. 7 is an enlarged vertical cross-sectional view of a main part showing another example of the core holding device. FIG. 7 is an enlarged vertical cross-sectional view of a main part showing another example of the core holding device.

This embodiment discloses the following features.
The first feature is that it includes a cylindrical lead holding holder that allows the lead to pass through and guide it forward, and an outer cylinder that covers the outer circumferential surface of this lead holding holder, and that the front end side of the lead holding holder is provided with a cylindrical lead holding holder that guides the lead forward. A core holding portion whose inner peripheral surface is gradually reduced in diameter toward the front so as to hold the outer peripheral surface, and a notch portion that separates the core holding portion in the circumferential direction are provided (Figs. 1 to 5). reference).

As a second feature, the core holding portion is formed by gradually increasing the thickness of the peripheral wall of the lead holding holder radially inward toward the front (see FIGS. 7 and 8).

As a third feature, an enlarged diameter portion is provided in which the diameter of the inner circumferential surface is gradually enlarged toward the front from the core holding portion and the thickness of the peripheral wall is thinned (see FIGS. 3 to 5).

As a fourth feature, the enlarged diameter portion is formed in a convex curved shape (see FIGS. 3 to 5).

As a fifth feature, the cut portion extends from the front end of the lead holder to the rear side of the lead holder.

As a sixth feature, the outer cylinder has a gap between it and the outer circumferential surface of the lead holding holder, and this gap allows the lead holding holder to bend in the radial direction (Figs. 3 to 5 reference).

As a seventh feature, the lead holding holder is provided with a diameter-reducing inclined portion in which the diameter of the outer circumferential surface is gradually reduced forward to the frontmost end (see FIGS. 3 to 5).

As an eighth feature, a mechanical pencil is provided with the lead holding device described above (see FIG. 1).

<Specific embodiment>
Next, a specific embodiment having the above characteristics will be described in detail based on the drawings.
In the following description, "front" means one side in the axial direction of the lead holding holder 31 in which the lead X protrudes, and "rear" means the opposite side to the one side. .

FIG. 1 shows a mechanical pencil equipped with a lead holding device according to the invention.
This mechanical pencil 1 includes an elongated barrel 10, a tip 20 connected to the front end of the barrel 10, a lead holding device 30 attached to the front end of the tip 20, and a tip 20 connected to the front end of the barrel 10. It is equipped with a knocking part 40 protruding from the rear end, and a lead feeding mechanism and a lead tank (not shown) housed in the barrel 10. By moving the knocking part 40 forward and backward, the lead feeding mechanism moves into the lead tank. The lead X is fed out, inserted into the tip 20 and the lead holding device 30, and projected to the outside.

Although the shaft cylinder 10 is a single cylindrical member in the illustrated example, it is also possible to have a configuration in which a plurality of cylindrical members are connected.

The tip 20 is a tapered cylindrical member, and is removably screwed onto the front end side of the shaft tube 10 . A lead holding device 30, which will be described later, is attached to the front end side of the tip opening 20.
In addition, this tip 20 can also be made into a member integral with the shaft cylinder 10 as another example.

The lead feeding mechanism is a well-known mechanism that feeds out the lead X in the lead tank, and other examples include a mode in which the lead is fed out by a rotating operation, and a mode in which the lead is fed out by a side knocking operation. .

The lead holding device 30 includes a cylindrical lead holding holder 31 through which the lead X is inserted and guided forward, and an outer cylinder 32 that covers the outer peripheral surface of the lead holding holder 31 (see FIGS. 4 and 5).

The lead holding holder 31 is formed from a hard metal material into a long, substantially cylindrical shape. This lead holding holder 31 is fixed coaxially with the tip 20 and the barrel 10 by press-fitting the rear end side into the tip 20 .
The material of the lead holding holder 31 may be any material other than metal, such as a synthetic resin material (including hard or soft materials), as long as it allows the lead holding holder 31 to bend in the radial direction. It is also possible.
Further, the means for fixing the lead holding holder 31 to the tip 20 may be adhesive, welding, caulking, fitting, etc. in addition to the above-mentioned press fitting.

The lead holding holder 31 is provided with a diameter-reducing inclined portion 31a whose diameter is gradually reduced forward on the outer peripheral surface up to the frontmost end of the lead holding holder 31.
The diameter-reducing inclined portion 31a includes a lead holding portion 31b whose inner circumferential surface is reduced in diameter so as to hold the outer circumferential surface of the lead An enlarged diameter portion 31c is provided in which the peripheral wall thickness is reduced while the diameter is enlarged (see FIG. 3).
Furthermore, this lead holding holder 31 is provided with a notch 31d (see FIG. 2) extending in an elongated shape from the front end of the peripheral wall to a portion on the rear side of the lead holding part 31b.

The diameter-reducing inclined portion 31a is, for example, a portion where the diameter of the outer circumferential surface of the metal cylindrical member that is the raw material of the lead holding holder 31 is gradually reduced forward to the frontmost end (see FIG. 3). This diameter-reducing inclined portion 31a may be formed, for example, by drawing using a mold.
On the inner circumferential surface of the lead holding holder 31, a portion on the rear side of the diameter-reducing inclined portion 31a is formed to have a slightly larger diameter than the outer circumferential surface of the lead X.
Further, in the outer circumferential surface of the lead holding holder 31, a portion on the rear side of the diameter-reducing inclined portion 31a is formed to have a slightly smaller diameter than the inner circumferential surface of a cylindrical portion 32a of the outer cylinder 32, which will be described later.

The core holding portion 31b is a portion where the inner diameter is the smallest on the front end side of the inner circumferential surface of the diameter-reducing inclined portion 31a. The core holding portion 31b is formed to have an inner diameter slightly smaller than the outer diameter of the core X so as to be in contact with the outer circumferential surface of the core X with an appropriate pressing force.

The enlarged diameter portion 31c has an inner circumferential surface gradually enlarged in diameter toward the front on the front side of the core holding portion 31b, and has a thinner circumferential wall thickness.
To explain in more detail, the enlarged diameter portion 31c is formed in a convex curved shape (in other words, a convex curved shape in longitudinal section) whose diameter gradually increases from the lead holding portion 31b toward the front. According to the example shown in FIG. 3, the frontmost end of the enlarged diameter portion 31c is located at the frontmost end of the lead holding holder 31.

A plurality of notches 31d are provided on the peripheral wall of the lead holding holder 31 at intervals in the circumferential direction (according to the illustrated example, two at equal intervals).
Each notch 31d extends rearward from the frontmost end of the lead holding holder 31 in a substantially straight line. According to the example shown in FIGS. 4 and 5, the rear end portion of this notch portion 31d is at a position inserted into the tip 20.
Each notch 31d separates the front part of the lead holding holder 31 including the lead holding part 31b in the circumferential direction.

Further, the outer cylinder 32 is formed of a hard metal material into a long, substantially cylindrical shape, and the rear end portion thereof is press-fitted into the tip end 20 on the front side of the press-fitted portion on the rear end side of the lead holding holder 31. . The outer cylinder 32 is fixed concentrically with the tip 20, the shaft cylinder 10, the lead holding holder 31, and the like.
This outer tube 32 has a cylindrical tube portion 32a that is close to the outer circumferential surface of the core holding holder 31, and a diameter-reduced portion 32b that is reduced in diameter at the front end side of this tube portion 32a.
In addition, as another example of the material of the outer cylinder 32, it is also possible to use a material other than metal, such as a synthetic resin material, as long as it can ensure appropriate strength.
Further, the means for fixing the outer cylinder 32 to the tip 20 may be, in addition to the above-mentioned press-fitting, adhesive, welding, caulking, fitting, or the like.

The cylindrical portion 32a has a gap s1 between it and the outer circumferential surface of the lead holding holder 31 so as to allow the lead holding holder 31 to bend in the radial direction and to restrict the amount of bending. This gap s1 continues to the rear end of the cylindrical portion 32a.
In the lead holding holder 31, the radial dimension of the gap s1 is approximately constant on the rear side of the diameter-reducing slope portion 31a, and increases toward the front in the portion of the diameter-reducing slope portion 31a.

The reduced diameter portion 32b is an annular projection that projects radially inward from the front end of the cylindrical portion 32a.
The inner diameter of this reduced diameter portion 32b is smaller than the outer diameter of the front end of the lead holding holder 31 and larger than the outer diameter of the lead X.

Further, the reduced diameter portion 32b is located on the front side of the front end portion of the lead holding holder 31 (see FIG. 3). A gap s2 is ensured between the inner circumferential surface of the reduced diameter portion 32b and the outer circumferential surface of the core X inserted therethrough so as to prevent the core X from coming into contact with the reduced diameter portion 32b and being damaged.

Next, the functions and effects of the mechanical pencil 1 having the above structure will be explained in detail.
When the knock portion 40 is operated to knock and the core X in the barrel 10 moves forward, the core X passes through the interior of the core holding device 30 and projects forward from the front end of the core holding device 30 (see FIG. 4).
In this state, when writing is performed and a force component in the radial direction due to writing pressure or the like is applied to the front end side of the lead X, the front end side of the lead X is slightly bent in the radial direction. This deflection is regulated by the front end side of the lead holding holder 31 bending in the radial direction and coming into contact with the inner circumferential surface of the outer cylinder 32. Therefore, the lead X may break due to this bending, or the lead X may be strongly pressed against the reduced diameter portion 32b. This can prevent damage caused by pressure welding.

Further, as shown in FIG. 5, when the leading lead X1 and the trailing lead X2 that contacts the leading lead X1 from behind are inserted into the lead holding device 30, the lead holding holder 31 having the notch 31d is inserted into the lead holding device 30. An elastic restoring force is generated in the circumferential wall in the direction of diameter reduction. Therefore, the leading lead X1 is pressed against and firmly held by the lead holding portion 31b whose diameter is to be reduced.
Therefore, even when writing is performed using the shortened lead lead X1, it is possible to prevent the lead lead X1 from rotating or coming off from the lead holding holder 31.

Also, the shortened leading core X1 (for example, a broken core, etc.). When attempting to insert the lead into the lead holding device 30 from the front side, the rear end of the leading lead X1 will not be caught by the front end of the lead holding holder 31, but will be guided to the enlarged diameter portion 31c and smoothly move backward. Moving.
The enlarged diameter portion 31c also has the effect of not damaging the core X that is held by the core holding portion 31b and protrudes forward.

As described above, according to the invention of this embodiment, the peripheral wall thickness of the lead holding holder 31 is gradually thinned toward the front, so that the enlarged diameter portion 31c is arranged near the front end of the lead holding holder 31. Therefore, the position of the core holding portion 31b can also be placed relatively closer to the front end. Therefore, shorter wicks can be held.

<Modified example>
According to the embodiment described above, the enlarged diameter portion 31c is formed into the above-mentioned convex curved shape, but the enlarged diameter portion 31c may be formed by gradually increasing the diameter of the inner peripheral surface toward the front and making the peripheral wall thinner. As other examples, it is possible to have a concave curved surface shape, a conical surface shape, an R chamfer shape, a C chamfer shape, etc.

Further, according to the embodiment described above, the notch 31d extends rearward from the frontmost end of the lead holding holder 31, but the notch 31d allows the lead holding holder 31 to be moved at least as far as the lead holding part 31b. Any material may be used as long as it is separated in the circumferential direction at a portion and is easily elastically deformed in the radial direction.
Therefore, for example, like a core holding holder 31' shown in FIG. 6, it is also possible to have an embodiment having a long hole-shaped cut portion 31d' extending in the front-rear direction.

Further, according to the embodiment described above, the lead holding holder 31 is inserted into the cylindrical outer tube 32, but as another example, the outer tube 32 may be other part of the mechanical pencil 1. good. For example, a through hole may be provided on the front end side of the tip 20, this through hole may function as the inner circumferential surface of the outer cylinder 32, and the lead holding holder 31 may be provided with a gap s1 secured within the through hole. It is also possible.

Further, in the lead holding device 30 of the above embodiment, the thickness of the peripheral wall of the lead holding holder 31 is gradually increased radially inward toward the front in order to form the lead holding part 31b, but as another example, It is possible to form the lead holding part 31b like the lead holding device 30S1 shown in FIG.
The lead holding device 30S1 is obtained by replacing the lead holding holder 31 in the lead holding device 30 described above with a lead holding holder 31S1.
The lead holding holder 31S1 forms a lead holding part 31b by gradually increasing the thickness of the front end of the peripheral wall radially inward toward the front.
According to the lead holding device 30S1 shown in FIG. 7, the lead holding part 31b can be arranged closer to the front end side, and as a result, a shorter bent lead can be held.

Furthermore, as another example, a core holding device 30S2 shown in FIG. 8 may be used. This lead holding device 30S2 is obtained by replacing the lead holding holder 31 in the lead holding device 30 described above with a lead holding holder 31S2.
The lead holding holder 31S2 is the same as the lead holding holder 31S1, but has an enlarged diameter part 31c in which the diameter of the inner peripheral surface is gradually enlarged from the lead holding part 31b toward the front, and the peripheral wall thickness is thinned.
According to the lead holding device 30S2 shown in FIG. 8, the lead holding part 31b can hold the broken lead on the front end side, and the enlarged diameter part 31c makes it easy to insert the lead X from the front. damage can be prevented.

The present invention is not limited to the embodiments described above, and can be modified as appropriate without changing the gist of the present invention.

1: Mechanical pencil 10: Barrel 20: Tip 30: Lead holding device 31: Lead holding holder 32: Outer cylinder 31a: Reduced diameter inclined part 31b: Lead holding part 31c: Expanded diameter part 31d: Notch part X: Lead s1 , s2: Gap

Claims (8)

It includes a cylindrical lead holding holder that inserts the lead and guides it forward, and an outer cylinder that covers the outer peripheral surface of this lead holding holder.
The front end side of the lead holding holder includes a lead holding part whose inner peripheral surface is gradually reduced in diameter toward the front so as to hold the outer peripheral surface of the lead, and a notch that separates the lead holding part in the circumferential direction. A lead holding device characterized by being provided with a section. The lead holding device according to claim 1, wherein the lead holding portion is formed by gradually increasing the thickness of the peripheral wall of the lead holding holder radially inward toward the front. 3. The lead holding device according to claim 1, further comprising an enlarged diameter portion in which the diameter of the inner circumferential surface is gradually increased toward the front from the lead holding portion and the thickness of the peripheral wall thereof is reduced. The lead holding device according to claim 3, wherein the enlarged diameter portion is formed in a convex curved shape. The lead holding device according to any one of claims 1 to 4, wherein the notch extends from the front end of the lead holding holder to the rear side of the lead holding part. Any one of claims 1 to 5, wherein the outer cylinder has a gap between it and the outer circumferential surface of the lead holding holder, and this gap allows the lead holding holder to bend in the radial direction. The core holding device according to item 1. The lead holding device according to any one of claims 1 to 6, wherein the lead holding holder is provided with a diameter-reducing slope portion whose outer circumferential surface is gradually reduced in diameter forward up to the frontmost end. A mechanical pencil comprising the lead holding device according to any one of claims 1 to 7.

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