JPH10309887A - Double chuck type mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a double chuck type mechanical pencil of a low cost having a tip chuck disposed at a head end of a tip implement to hold a lead and a letting-out chuck for letting out the lead. SOLUTION: In the double chuck type mechanical pencil comprising a barrel 10, a tip implement 12 provided at a front part of the barrel 10, a tip chuck 30 disposed at the front part of the barrel 10 to hold a lead 52 and urged rearward in an axial direction, and a letting-out chuck 16 for letting-out the lead 52 so that the chuck 30 is advanced to advance the chuck 16 in the state that the lead 52 is released to let out the lead 52, the chucks 30, 16 are formed of synthetic resin material containing polyacetal as a main component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-chuck mechanical pencil having a tip chuck disposed at the tip of a leading tool for holding a lead, and a feeding chuck for feeding the lead.

[0002]

2. Description of the Related Art Conventionally, such a mechanical pencil having two chucks has been disclosed in Japanese Utility Model Laid-Open No. 54-119435.
Is described in Japanese Patent Application Publication No.

[0003]

However, the tip chuck and the feed-out chuck of such a mechanical pencil are conventionally formed of a metal material, and when these are manufactured, a substantially cylindrical shape is ground and then the cutter is cut. The head must be divided into three (or two) chuck elements, and secondary processing such as deburring must be performed. If the chuck element is too open in the tip chuck, the tip may move forward to release the lead, and the lead may fall. Processing must be performed. For this reason, there is a problem that the production is troublesome and the production cost is increased.

[0004] The present invention has been made in view of the above problems, and an object of the present invention is to provide a double-chuck mechanical pencil that can reduce the manufacturing cost. I do.

[0005]

Means for Solving the Problems To achieve the above object, the invention according to claim 1 comprises an outer cylinder, a leading tool provided at a front portion of the outer barrel, and a leading tool for holding a core. It has a tip chuck placed at the tip and urged backward in the axial direction, and a feeding chuck for feeding out the lead. The tip chuck is advanced and the lead is released while the lead is released. In the pencil, at least one of the tip chuck and the feeding chuck is formed of a synthetic resin material.

[0006] By forming a synthetic resin material and molding it into a desired shape, it is not necessary to perform secondary processing such as deburring or expanding or narrowing the tip of the chuck. The number of steps can be reduced, and the manufacturing cost can be reduced. The invention according to claim 2 is claim 1
In the above description, the synthetic resin material is mainly composed of polyacetal.

As a result, a chuck having excellent wear resistance and high mechanical strength can be obtained. According to a third aspect of the present invention, in the first aspect, the synthetic resin material is obtained by mixing glass fibers into a material mainly composed of polyacetal.

[0008] Thus, the chuck can be made to have elasticity, and the core can be made less likely to be damaged when the core is held. Glass fiber is 5-20 by weight
%, Preferably about 15%. The invention according to claim 6 is characterized in that, in any one of claims 1 to 5, the synthetic resin material is obtained by mixing a lubricant with a material mainly containing polyacetal. .

Thus, for example, the sliding can be smoothly performed between the leading tool and the tip chuck or the feeding chuck and its peripheral members. Specifically, molybdenum, silicon, and tungsten can be used as the lubricant. According to a seventh aspect of the present invention, in any one of the first to sixth aspects, at least the tip chuck is formed of a synthetic resin material.

The invention according to claim 8 is characterized in that, in the invention according to claim 7, the tip chuck is colored differently depending on the core diameter. Thus, the user can easily see the color of the tip chuck to find out at a glance the core diameter suitable for the mechanical pencil. According to a ninth aspect of the present invention, in the device according to any one of the seventh and eighth aspects, the tip chuck is provided with a step surface capable of contacting the tip face of the leading tool, and is provided after the tip chuck. The end is connected to a tip of a core feeding mechanism disposed in the tip by inserting the tip of the tip.

When the tip is disassembled from the outer cylinder, the step surface of the tip chuck comes into contact with the tip face of the tip, so that the tip chuck and the centering mechanism do not come off from the tip and the parts are separated. There is no risk of loss. Since the tip chuck is made of a synthetic resin material, the step surface can be easily formed by molding. According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the chuck formed of the synthetic resin material of at least one of the tip chuck and the feed-out chuck has a head having a circumferential shape. It consists of a plurality of chuck elements divided in the direction, and the adjacent chuck elements formed when the plurality of chuck elements are approached so that the outline of the outer shape formed by the plurality of chuck elements when viewed from the axial direction becomes a perfect circle. The circumferential gap is 0.15 mm or less.

When a chuck is formed of a conventional metal material, the chuck having a substantially cylindrical shape is divided into a plurality of chuck elements by using a cutter. Blade width (0.15mm
However, the chuck can be formed into a desired size by molding by forming the chuck with a synthetic resin material. Accordingly, when a plurality of chuck elements are brought close to each other so that the outline of the outer shape formed by the plurality of chuck elements when viewed from the axial direction becomes a perfect circle, the circumferential gap between adjacent chuck elements is 0.15 mm or less. The contact area of the core held by the chuck element with the chuck element can be increased, and the core can be reliably clamped by the chuck element.

According to an eleventh aspect of the present invention, in any one of the first to tenth aspects, the tip chuck and the feed-out chuck are respectively divided along a circumferential direction from a head thereof to a rear thereof and separated from each other. The axial length of the chuck element, which includes a plurality of chuck elements and moves away from each other, is characterized in that the length of the chuck element of the tip chuck is shorter than the length of the chuck element of the feeding chuck.

With this configuration, the degree of opening of the chuck element of the tip chuck can be made smaller than the degree of opening of the chuck element of the feeding chuck. Therefore, when the lead is short and the lead is located ahead of the feeding chuck, the chuck element of the tip chuck does not open too much even when the tip chuck releases the lead, and the lead is held so that the lead does not drop. You can keep power.

According to a twelfth aspect of the present invention, in any one of the first to eleventh aspects, the axial length of the holding portion for holding the inner core of each of the tip chuck and the feeding chuck is: The length of the holding portion of the tip chuck in the axial direction is longer than the length of the holding portion of the feeding chuck in the axial direction. With such a configuration, the lead can be firmly held by the tip chuck at the tip, so that breakage of the lead can be prevented.

According to a thirteenth aspect of the present invention, in any one of the first to twelfth aspects, a projection is provided at a rear end of the tip chuck, and a rear end provided with the projection is a front end. The tip of the tool is inserted into the through-hole of the center cylinder provided in the tool by inserting the tip of the tool into the tip of the tool. An enlarged diameter portion which escapes the projection is formed at the rear.

The engagement between the projection of the tip chuck and the step surface of the center cylinder prevents the tip chuck from coming off the center cylinder, and the enlarged diameter portion that escapes the projection of the tip chuck is formed in the center cylinder. Accordingly, it is possible to prevent the center cylinder from being damaged without applying a radial load from the projection to the center cylinder at all times.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of a double chuck mechanical pencil according to the present invention. In FIG. 1, reference numeral 10 denotes an outer cylinder, and a front tool 12 fixed by screwing, bonding or the like is provided at a front portion of the outer cylinder 10.

A core feeding mechanism 14 is provided inside the outer cylinder 10 and the leading tool 12. The center feeding mechanism 14 includes a feeding chuck 16 for feeding a lead, and a feeding chuck 16.
A chuck ring 18 which is fitted over the head of the feed chuck 16 to fasten the head of the feed chuck 16, a sleeve 20 which comes into contact with the rear end of the chuck ring 18, a lead tank 22 connected to the feed chuck 16, and a front end of the lead tank 22 A first chuck spring 24 interposed between the first chuck spring 24 and the front end of the sleeve 20 for urging the feeding chuck 16 rearward in the axial direction via the core tank 22;
8, a rubber member 27 disposed in the center cylinder 26 to hold the core by frictional force, and a core tank 22.
And a rear sleeve 28 connected to the rear end by press fitting. The front end of the sleeve 20 abuts on a step 26 b provided on the inner peripheral surface of the central portion of the through hole 26 a of the central barrel 26, and a locking hole 2 provided on the rear peripheral surface of the central barrel 26.
6c, the protrusion 20a of the sleeve 20 is locked,
The middle barrel 26 and the sleeve 20 are integrally connected.
However, the center cylinder 26 and the sleeve 20 can be formed as one part.

At the end of the through hole 26a of the center cylinder 26,
The tip chuck 30 is press-fitted through the tip of the tip tool 12. More specifically, as shown in FIG.
A projection 30a is formed on the outer periphery of the rear end of the tip chuck 30. On the other hand, a step surface 26d is provided at the front of the inner peripheral surface of the through hole 26a of the center cylinder 26, and the step surface 26d is formed behind the step surface 26d. The enlarged diameter portion 26e has a larger inner diameter than the front portion. Then, the projection 30a is press-fitted from the distal end of the center cylinder 26 to the distal end of the through hole 26a, and is locked to the step surface 26d beyond the step surface 26d.
After that, the enlarged diameter portion 26e serves as a relief for the projection 30a, so that the projection 30a does not interfere with the enlarged diameter portion 26e in the radial direction. Thus, the radial load from the projection 30a is always prevented from being applied to the middle barrel 26, and the middle barrel 26 is prevented from being damaged.

A second chuck spring 3 is provided between the distal end of the center barrel 26 and the step 12 a provided inside the tip tool 12.
2, which urges the distal end chuck 30 rearward in the axial direction via the middle barrel 26. The second chuck spring 32 is selected to have a lower elasticity than the first chuck spring 24. The tip chuck 30 is further formed with a step face 30 b facing rearward, and the step face 30 b is pressed against the tip face 12 b facing forward of the leading tool 12 by the urging force of the second chuck spring 32. . If the step surface 30b interferes with the tip end surface 12b of the tool 12, the tip chuck 30 and the core feeding mechanism 14 are not disassembled separately even when the tool 12 is detached from the outer cylinder 10. Has become.

The outer peripheral surface of the rear sleeve 28 and the inner peripheral surface of the outer cylinder 10 are prevented from rotating by a key and a key groove. Further, an eraser holding cylinder 40 is connected to the rear end of the rear sleeve 28 by press fitting, and an eraser 42 is detachably fitted into the eraser holding cylinder 40. 44 is a knock cap covering the eraser, 46 is a tail plug, 48 is a tail plug 4
A clip 50 sandwiched between the rear end of the outer cylinder 10 and a rubber gripper 50 wound around a grip portion of the outer cylinder 10.

The feeding chuck 16 and the tip chuck 3
Numeral 0 is not a metal material but a synthetic resin material. As a specific material, a material mainly composed of polyacetal (Polyxymethylene, POM) having excellent abrasion resistance and high mechanical strength is preferably used. . When glass fibers are mixed with the polyacetal in a weight ratio of 5 to 20%, preferably about 15%, the elasticity is further increased, and damage to the core when holding the core can be reduced. Further, when a lubricant such as molybdenum, silicon, tungsten, or the like is mixed, the sliding between the tip chuck 30 and the leading end 12 or the feeding chuck 16 and the chuck ring 1 are performed.
8 can be prevented from being worn by sliding. In the case of a metal chuck, such a lubricant is applied, but when formed of a synthetic resin material, it can be mixed and molded together, such as an application operation. No more hassle.

The tip chuck 30 can be colored by appropriately mixing a coloring agent into the synthetic resin material. For example, 0.5 m according to ISO9175-1
m core diameter is brown, 0.3 mm core diameter is yellow,
If the 0.7 mm core diameter is colored such as blue, it is convenient for the user to see at a glance the core diameter suitable for this mechanical pencil.

FIGS. 2A and 2B show the feeding chuck 16.
3A and 3B show a front view and a vertical cross-sectional view of the distal end chuck 30, and each figure shows a state in which the chuck is closed. The feeding chuck 16 and the tip chuck 30 are each divided into three along the circumferential direction from the head to the rear thereof.
Is a three-pronged chuck composed of three chuck elements 17 and three chuck elements 31,
7 and the axial length of the chuck element 31, that is, L 1 and L 2 in FIGS. 2 and 3, the length L 2 of the chuck element of the tip chuck 30 is longer than the length L 1 of the chuck element of the feeding chuck 16. It is set to be shorter. With this configuration, the degree of opening of the chuck element 31 of the tip chuck 30 can be made smaller than the degree of opening of the chuck element 17 of the feeding chuck 16. Therefore, even when the tip chuck 30 releases the core 52, the chuck element 31 of the tip chuck 30 does not open too much, and a core holding force that does not drop the core 52 can be maintained.

The feeding chuck 16 and the tip chuck 3
0, holding portions 16a and 30c extending substantially parallel to the axial direction are respectively provided to hold the core 52. The lengths L3 and L4 of the holding portions 16a and 30c in the axial direction are respectively set as follows. The holding portion 3 of the tip chuck 30 is longer than the length L3 of the holding portion 16a of the feeding chuck 16 in the axial direction.
The length L4 in the axial direction of 0c is set to be longer. Accordingly, the tip chuck 30 can more securely hold the core 52 than the feeding chuck 16, and the core 52 can be prevented from being broken during writing by firmly holding the core 52 at the tip. Further, since it is expected that the pinching force of the core is inferior to that formed of a synthetic resin material as compared with that formed of a metal material, the lengths L3, L4
Is preferably set to be longer than a metal chuck.

Further, the chuck elements 17, 31 of the feeding chuck 16 and the tip chuck 30, respectively, are shown in FIG.
As shown in FIG. 3A and FIG. 3A, three chuck elements 17 and three chuck elements 31 when viewed from the axial direction.
The gaps d1 between the adjacent chuck elements 17 and the gap d2 between the adjacent chuck elements 31 formed when the chuck elements 17 and the chuck elements 31 are brought close to each other so that the outline of the outer shape becomes a perfect circle are endless. 0
, Specifically, it is set to be 0.15 mm or less. With such a setting, the area where the core held by the chuck elements 17 and 31 comes into contact with the chuck elements 17 and 31 can be increased, and the chuck element 1
The core can be securely clamped by 7 and 31.

By the way, when forming the feeding chuck 16 and the tip chuck 30, each chuck element 1
7. It is necessary to form each chuck element 31 in advance so that it can be released from the core in the radial direction. For example, FIG. 4 is a side view when the feeding chuck 16 is in a free state, and the chuck elements 17 are formed in a state where they are radially spread from each other. Since the chuck elements 17 and 31 tend to return radially inward due to the return spring force after the resin has been molded and at the end of molding, the degree of opening of the chuck elements 17 and 31 should be adjusted in consideration of these factors. . Also, the chuck element 31 is formed so as to have a smaller radial expansion than the chuck element 17, and the axial length of the chuck element 31 is shorter than the chuck element 17 as described above. In this case, the holding force of the core of the tip chuck 31 can be maintained. In this way, the chuck element 17 and the chuck element 31 can be formed so as to have an appropriate opening degree, an appropriate axial length, and a very small gap when approached to each other. Since it is possible, secondary processing unlike the case of metal is not required, and the number of steps can be reduced. In addition, since the desired shape can be obtained by molding, the projection 30a and the step surface 30b of the tip chuck 30 can be easily formed.

FIG. 6 is a view showing another example of the tip chuck 30. The tip chuck 30 is configured by vertically aligning a plurality of (two in the illustrated example) parts and chuck members 30-1 and 30-1, and as shown in FIG. A projection 30-1a and a hole 30-1b are formed on the mating surface of the first chuck member 3.
0-1 hole 30-1b in the other chuck member 30-b.
By fitting one of the projections 30-1a, the two constitute an integrated tip chuck 30. These rear ends are integrally press-fitted into the central barrel 26. As described above, the rear portions of the chuck members 30-1 and 30-1 are integrally connected, while the front end portions are slightly warped so as to be separated from each other, and the two chucks divided into two along the circumferential direction. Elements 31 and 31 constitute. Chuck element 3
The axial lengths of 1, 31 are indicated by L2 in the figure. As described above, the tip chuck 30 is constituted by the plurality of chuck members 30-1 and 30-1, and each chuck member 30-1
1 are individually molded into a desired shape, so that the length L1
The degree of opening of the chuck elements 31 can be set to a desired size. Further, the gap between adjacent chuck elements 31 formed when the chuck elements 31 are brought close to each other so that the outline of the outer shape formed by the two chuck elements 31 and 31 when viewed from the axial direction becomes a perfect circle is reduced to zero as much as possible. You can easily get closer.

When assembling the above parts, first,
The core feeding mechanism 14 is assembled, and then inserted into the leading tool 12 via the second chuck spring 32, and the leading tool 1
As described above, the rear end of the tip chuck 30 is pressed into the center cylinder 26 of the center feeding mechanism 14 from the front end of the second chuck 2. Then
After the leading tool 12 is fixed to the outer cylinder 10, the eraser holding cylinder 40 is press-fitted into the rear sleeve 28, and the other components are assembled and the process is completed.

In the double chuck mechanical pencil constructed as described above, when the knock cap 44 is knocked in order to feed out the lead 52, the second chuck spring 32 has a lower elastic force than the first chuck spring 24. , The second chuck spring 32
Is retracted, the center feeding mechanism 14 advances, and the tip chuck 3
0 also advances with this, and protrudes from the leading tool 12 to release the core 52. Further, when the knock cap 44 is knocked,
Since the first chuck spring 24 of the center feeding mechanism 14 is compressed, the feeding chuck 16 advances, and the core 52 is fed. Even when the lead is worn and becomes shorter than the length between the tip chuck 30 and the feed chuck 16, if the knock cap 44 is knocked, the lead is released to the extent that the lead does not drop from the tip chuck 30, and the knock cap 4
By knocking 4, the next lead advanced from the delivery chuck 16 can press the previous lead and pay out the previous lead. The core shortened in this way can also be written. When the hand is released from the knock cap 44, the feeding chuck 16 and the tip chuck 30 are retracted in the axial direction by the urging force of the first chuck spring 24 and the second chuck spring 32, and the core is again held. Thus, it becomes possible to write.

By forming the feeding chuck 16 and the tip chuck 30 from a synthetic resin material, the elasticity of the synthetic resin material allows the core 52 to be held even when the core 52 is sandwiched between both.
Since the core 52 is held softly, it is possible to prevent the core 52 from being damaged. Further, even if two chucks are provided, by forming the chuck with a synthetic resin material, the material cost and the manufacturing process can be reduced, and the manufacturing cost can be reduced.

In this embodiment, an example in which both the feed chuck and the tip chuck are formed of a synthetic resin material has been described. However, although the manufacturing cost is slightly disadvantageous, the feed chuck and the tip chuck are not provided. Either one may be formed of a synthetic resin material. In particular, when the feeding chuck is formed of a synthetic resin material, the return amount of the core when the chuck is retracted tends to be large. Therefore, only the tip chuck may be formed of a synthetic resin material.

[0034]

As described above, according to the first aspect of the present invention, at least one of the tip chuck and the feeding chuck is formed of a synthetic resin material, and is formed into a desired shape to remove burrs. Secondary processing such as expanding or narrowing the tip of the chuck or the like becomes unnecessary, so that material costs and manufacturing steps can be reduced, and manufacturing costs can be reduced.

According to the second aspect of the present invention, by using the synthetic resin material containing polyacetal as a main component, a chuck having excellent wear resistance and high mechanical strength can be obtained. According to the invention according to claim 3, the synthetic resin material is mainly composed of polyacetal,
By incorporating glass fibers, the chuck can be given elasticity, the core can be held softly, the damage to the core can be reduced, and the core can be prevented from breaking.

According to the fourth and fifth aspects of the present invention, the chuck can be given an appropriate elasticity. According to the invention as set forth in claim 6, the synthetic resin material is composed mainly of polyacetal and a lubricant is mixed therein. Sliding can be performed smoothly between the two.

According to the seventh aspect of the invention, since the tip chuck is formed of a synthetic resin material, the material cost and the manufacturing process can be reduced, and the manufacturing cost can be reduced. According to the invention according to claim 8, the tip chuck is colored differently according to the core diameter, so that the user can see the color of the tip chuck and fit the mechanical pencil at a glance. The diameter is easy to understand.

According to the ninth aspect of the present invention, when the leading end and the outer cylinder are disassembled, the step surface of the leading end chuck abuts on the leading end surface of the leading end. There is no risk of parts falling apart and being lost without coming off the tool. Since the tip chuck is made of a synthetic resin material, the step surface can be easily formed by molding.

According to the tenth aspect of the present invention, the gap between the adjacent chuck elements can be reduced, so that the area where the core held by the chuck element contacts the chuck element can be increased. As a result, the core can be reliably held by the chuck element. Claim 1
According to the first aspect of the invention, since the axial length of the chuck element of the tip chuck is set to be shorter than the axial length of the chuck element of the feeding chuck,
The opening degree of the chuck element of the tip chuck can be made smaller than the opening degree of the chuck element of the feeding chuck. Therefore, when the lead is short and the lead is located ahead of the feeding chuck, the chuck element of the tip chuck does not open too much even when the tip chuck releases the lead, and the lead is held so that the lead does not drop. You can keep power.

According to the twelfth aspect, the length of the holding portion of the tip chuck in the axial direction is set to be longer than the length of the holding portion of the feeding chuck in the axial direction. The core can be firmly clamped by the tip chuck, and breakage of the core can be prevented. Claim 13
According to the invention according to the above, the engagement between the projection of the tip chuck and the step surface of the center cylinder can prevent the tip chuck from coming off from the center cylinder, and the enlarged diameter portion that escapes the projection of the tip chuck is formed in the center cylinder. By doing so, it is possible to prevent the center cylinder from being damaged without the radial load from the projection always being applied to the center cylinder.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a double chuck mechanical pencil according to the present invention.

FIGS. 2 (a) and 2 (b) are a front view and a longitudinal sectional view of a feeding chuck 16. FIG.

3 (a) and 3 (b) are a front view and a longitudinal sectional view of a tip chuck 30. FIG.

FIG. 4 is a side view when the feeding chuck is in a free state.

FIG. 5 is an enlarged view of a distal end portion of FIG. 1;

6A and 6B show another example of the tip chuck, wherein FIG. 6A is a front view, FIG. 6B is a longitudinal sectional view, and FIG. 6C is a plan view of one chuck member constituting the tip chuck.

DESCRIPTION OF SYMBOLS 10 outer cylinder 12 leading tool 12b tip end face 14 core feeding mechanism 16 feeding chuck 16a holding section 17 chuck element 26 center shaft pipe 26a through hole 26d stepped surface 26e enlarged diameter section 30 tip chuck 30a projection 30b stepped surface 30c holding Part 31 Chuck element

[Procedure amendment]

[Submission date] December 26, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

The engagement between the projection of the tip chuck and the step surface of the center cylinder prevents the tip chuck from coming off the center cylinder, and the enlarged diameter portion that escapes the projection of the tip chuck is formed in the center cylinder. Accordingly, it is possible to prevent the center cylinder from being damaged without applying a radial load from the projection to the center cylinder at all times. The invention according to claim 14 is the claim
Item 14. The method according to any one of Items 1 to 13, wherein
The tip chuck combines multiple chuck members as separate parts.
It is characterized by being comprised from the thing which made it. like this
By configuring each chuck member individually as desired
The tip chuck can be easily shaped to the desired size by forming it into a shape.
Law can be set.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

The feeding chuck 16 and the tip chuck 3
0 is not a metal material is formed of a synthetic resin material, as a specific material excellent in wear resistance, high mechanical strength polyacetal (Poly o xymethylene, POM) is a material chiefly containing used And good. When glass fibers are mixed with the polyacetal in a weight ratio of 5 to 20%, preferably about 15%, the elasticity is further increased, and damage to the core when holding the core can be reduced. Furthermore, when a lubricant such as molybdenum, silicon, or tungsten is mixed, wear caused by sliding between the tip chuck 30 and the leading tool 12 or sliding between the feeding chuck 16 and the chuck ring 18 can be avoided. it can.
In the case of a metal chuck, such a lubricant is applied, but when formed of a synthetic resin material, it can be mixed and molded together, so that it is not necessary to apply such a lubricant. No more hassle.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction contents]

According to the twelfth aspect, the length of the holding portion of the tip chuck in the axial direction is set to be longer than the length of the holding portion of the feeding chuck in the axial direction. The core can be firmly clamped by the tip chuck, and breakage of the core can be prevented. Claim 13
According to the invention according to the above, the engagement between the projection of the tip chuck and the step surface of the center cylinder can prevent the tip chuck from coming off from the center cylinder, and the enlarged diameter portion that escapes the projection of the tip chuck is formed in the center cylinder. By doing so, it is possible to prevent the center cylinder from being damaged without the radial load from the projection always being applied to the center cylinder. The invention according to claim 14
According to the above, the tip chuck has a plurality of separate chucks.
Each member is composed of a combination of
By individually shaping the lock members into the desired shape,
The jack can be easily set to a desired size.

Claims (13)

[Claims] 1. An outer cylinder, a tip provided at a front portion of the outer cylinder, a tip chuck disposed at a tip of the tip to hold the lead, and urged rearward in the axial direction, and feeds the lead. A mechanical pencil has a feed chuck for moving the tip chuck forward and releasing the lead to advance the feed chuck to feed the lead. At least one of the tip chuck and the feed chuck is formed of a synthetic resin material. A double chuck type mechanical pencil characterized by the following. 2. The double-chuck mechanical pencil according to claim 1, wherein said synthetic resin material is mainly composed of polyacetal. 3. The double-chuck mechanical pencil according to claim 1, wherein the synthetic resin material is a material mainly composed of polyacetal and mixed with glass fibers. 4. The double-chuck mechanical pencil according to claim 3, wherein 5 to 20% by weight of glass fiber is mixed. 5. The double-chuck mechanical pencil according to claim 3, wherein about 15% by weight of glass fiber is mixed. 6. The double-chuck mechanical pencil according to claim 1, wherein the synthetic resin material is a material mainly composed of polyacetal mixed with a lubricant. 7. A double-chuck mechanical pencil according to claim 1, wherein at least the tip chuck is formed of a synthetic resin material. 8. The tip chuck according to claim 7, wherein the tip chuck is colored differently according to a core diameter.
The double-chuck mechanical pencil described in 1. 9. The tip chuck is provided with a step surface capable of abutting on the tip face of the tool, and the rear end of the tip chuck is disposed in the tool through the tip of the tool. 9. A double-chuck mechanical pencil according to claim 7, wherein the mechanical pencil is connected to a tip of a center feeding mechanism. 10. A chuck formed of the synthetic resin material of at least one of a tip chuck and a feed-out chuck, the head of the chuck being composed of a plurality of chuck elements divided along a circumferential direction, and from the axial direction. When a plurality of chuck elements are brought close to each other so that the outline of the outer shape formed by the plurality of chuck elements becomes a perfect circle, the circumferential gap between adjacent chuck elements is 0.15 mm or less. The double-chuck mechanical pencil according to any one of claims 1 to 9, wherein: 11. The tip chuck and the ejection chuck each include a plurality of chuck elements which are divided along the circumferential direction from the head to the rear thereof and are separated from each other. 2. The chuck element according to claim 1, wherein a length of the chuck element of the tip chuck is shorter than a length of the chuck element of the chuck.
0. A double-chuck mechanical pencil according to any one of 0. 12. An axial length of the holding portion for holding the inner cores of the tip chuck and the feeding chuck, respectively, is longer than an axial length of the holding portion of the feeding chuck. The double-chuck mechanical pencil according to any one of claims 1 to 11, wherein the length of the mechanical pencil is longer. 13. A rear end of the tip chuck is provided with a projection, and the rear end provided with the projection is inserted through the tip of the front tool, and is provided in the front tool. And a stepped surface that comes into contact with the projection of the tip chuck and a diameter-enlarging portion that escapes the projection behind the stepped surface at the tip of the through hole. Item 13. A double-chuck mechanical pencil according to any one of Items 1 to 12.