JPH0848098A - Mechanical pencil - Google Patents

Abstract

PURPOSE:To open wide a lead holding member without being controlled even if the diameter of the lead is comparatively large, by a method wherein the lead holding member formed into a little smaller external form than an internal form of a lead protective pipe is play-fitted within the protective pipe. CONSTITUTION:A lead holding member is opened wide in the diametral direction on the inside of the lead protective pipe without being controlled by a gap 10 to be generated between the lead holding member and insertion hole 9 even if the lead having a large diameter by a deviation is inserted. A rotation of the lead holding member at the time of writing is controlled by a form of the inside of the lead protective pipe 5 and the rotation of the lead holding member is prevented. Then, since the lead is inserted and an end face of the lead holding member is led to the surface 12 vertical to a holding ring 11, further the lead is inserted into the front holding ring 11, positioning is performed precisely. Furthermore, since a slope and roundness 6a, 11a are formed on the inside of the end part of the lead hoding member and holding ring 11, the lead is inserted easily into the lead holding member and a breakage by writing pressure can be prevented as much as possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sharp pencil in which a lead-out mechanism is arranged in a barrel and a lead holding tube is arranged at the tip of the barrel.

[0002]

2. Description of the Related Art When a lead is shortened in writing, this lead is a 30% chuck for gripping the lead of a lead feeding mechanism,
It is released from a chuck such as a ball chuck. The core released from the chuck remains between the tip of the chuck and the tip of a sharp pencil (core protection tube). The remaining lead (hereinafter referred to as "remaining lead") is only lightly held by the lead detent member. Therefore, when writing is performed on this residual core portion, the core rotates, and the writing feeling deteriorates, and generally, the core is extruded and discharged by the succeeding core, or pulled out and discarded. In particular, if the residual core is separated from the core detent member, the above-mentioned phenomenon is noticeable, and the core may eventually fall from the core protection tube due to its own weight.

Therefore, various proposals have been made for a lead protection tube in order to eliminate or minimize the residual lead and to effectively utilize the lead. The applicant of the present application also made a utility model 3-90992 as a device for effectively utilizing the core. Briefly described, a powder is dispersed and adhered to the inner surface of a core holding member having a non-circular cross section with a slit formed in the core insertion direction through a base material. The core is sandwiched between the core-holding member having the slit and the powder so that the user can write without feeling discomfort even when the core is left.

[0004]

However, although the residual core can be effectively utilized, in the embodiment shown in FIGS. 11 and 12, there is a large variation in the diameter of the core (by the way, JIS ( Japanese Industrial Standard) S6
The core having a nominal diameter of 0. 15 mm in 013 has the following problems depending on the allowable range of 0.55 mm to 0.58 mm. When the variation in the diameter of the lead is small, it is absorbed by the play portion (14), and the residual lead writing can be performed well. However, if the diameter of the core varies widely (if the core varies toward the thicker side), the expansion amount of the core holding member may exceed its permissible range (permissible bending range), cause plastic deformation, and may not be restored. It was Further, when the lead holding member tries to expand and deform to the vicinity of the inner surface of the tip end of the shaft cylinder, the expansion amount of the lead holding member is regulated by the contact between the lead holding member and the inside of the shaft cylinder. Unreasonable expansion force acts on the holding member, and the core holding member is no longer restored.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a shank having a lead-out mechanism arranged in the barrel and a lead protection tube arranged at the tip of the barrel. In the pencil, a core holding member formed in an outer shape slightly smaller than the inner shape of the core protecting tube is loosely inserted inside the core protecting tube, and a rotation preventing means for preventing the core holding member from rotating is core-protected. The gist is that it is placed inside the pipe.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 1 is a shaft of a sharp pencil. Inside the shaft cylinder 1, a chuck 3 having a chuck ring 2 fitted on the outer circumference of a front portion is shown (a three-piece chuck is shown in the figure). However, it may be a chuck generally called a ball chuck). Although the tip member 4 is screwed to the front of the barrel 1, the tip member 4 may be integrated with the barrel 1. Further, the lead protection tube 5 made of metal, synthetic resin or the like is press-fitted into the tip of the tip member 4, but the lead protection tube 5 may be integrated with the tip member 4. Inside the lead protection tube 5, a lead holding member 6 (remaining lead holding means) that holds the lead lead L is arranged. Reference numeral 7 is
Although it is a core detent that holds the core L lightly, the core detent is not always necessary. The above configuration is
It is the same as the conventional configuration. The feature of the present invention resides in the method of disposing the lead holding member 6 on the lead protection tube 5.

Each embodiment will be described below. A first example will be described with reference to FIGS. 2 to 4. Inside the lead protection tube 5, a lead holding member 6 having a triangular cross section is arranged. On one side of the core holding member 6 having a triangular cross section,
The slit 8 is formed and can be expanded in the radial direction.
The core holding member 6 was produced by rolling a plate-shaped member made of a metal material such as stainless steel or phosphor bronze into a triangular shape. However, a slit was formed in the pipe-shaped material and compression-formed so that the cross section had a triangular shape. You may form by. A narrowed portion 5a is formed at the tip of the lead protection tube 5 by crimping, rolling, or the like, so that the tip of the lead during writing is easy to see and easy to write. Further, the inside of the lead protection tube 5 is formed to be slightly larger than the outer shape of the lead holding member 6, and an insertion hole 9 having a triangular cross section is formed. The gap 1 formed between the lead holding member 6 and the insertion hole 9
0 has a nominal diameter of 0.5 m according to JIS S6013
In the case of using the m core, 0.04 mm or more is preferable in consideration of the range of core dispersion, but the core is not limited to this.

Reference numeral 11 is a holding ring for preventing the lead holding member 6 from coming off from the lead protecting tube 5. When the tip member 4 and the lead protecting tube 5 are integrally molded of resin or the like, 6
At the tip of the lead protection tube portion 4a as shown in FIG.
May be integrally formed, and the retaining ring 11 may be press-fitted in the rear. Also, in this example, the retaining ring 11
Although it was press-fitted and fixed to the inside of the lead protection tube 5, it may be fixed to the end surface of the lead protection tube 5 by adhesion or welding as shown in FIG. A surface portion 12 perpendicular to the side surface of the lead protection tube 5 is formed on these retaining rings 11,
The core holding member 6 is held by bringing the end portion of the core holding member 6 into contact with the vertical surface portion 12.

Next, the operation will be described. Wick holding member 6
Even if a core having a large core diameter due to variations is inserted, the core holding member 6 expands in the radial direction without being restricted by the inner surface of the core protection tube 5 due to the gap 10 generated between the core protection tube 5 and the insertion hole 9. Further, the rotation of the lead holding member 6 at the time of writing is restricted by the shape of the inside of the lead protection tube 5, and the rotation of the lead holding member 6 is prevented. Here, when the lead is not inserted in the lead holding member 6, the lead holding member 6 tilts or comes into surface contact as shown in FIGS. 4 and 5. However, by inserting the core, the end surface of the core holding member 6 is also changed to the holding ring 1.
By being guided to the vertical surface 12 of 1 and by further inserting the core into the retaining ring 11 in the front, it is accurately positioned (see FIGS. 2 and 3). Further, since the lead L is positioned by the holding ring 11, the lead lead L during writing
Does not swing. Further, by forming inclined surfaces and rounded portions 6a, 11a inside the ends of the lead holding member 5 and the holding ring 11 (particularly in the lead insertion direction side), the lead can be easily inserted into the lead holding member 6, and the brush It is also possible to prevent breakage due to pressure as much as possible.

The entire length of the core holding member 6 may be formed to be slightly shorter than the distance between the front and rear holding rings 11 fixed to the core protecting tube 5, so that the core holding member 6 can be expanded more. It will be easier. That is, the rotation of the core L and the core holding member 6 can be prevented without contacting both ends of the core holding member 6 with the vertical surface 12 of the holding ring 11. Further, by using a rubber-like elastic member such as plastic or silicone rubber for the material of the core holding member 6, it is not necessary to form a slit in the core holding member 6 as shown in FIGS. 8 and 9. Become. This is because the lead holding member itself can be expanded relatively easily.

A second example will be described with reference to FIGS. 10 and 11.
This is an example in which the overall length of the core holding member 6 is made slightly shorter and the protrusions 13 are formed at both ends of the core holding member 6. Then, the protrusion 13 is brought into contact with the vertical surface portion 12 of the retaining ring 11. In this way, by bringing one portion (projection 13) of the end portion of the lead holding member 6 into contact with the holding ring 11, when the lead holding member 6 expands, the holding ring 11
The frictional resistance on the contact surface between the core holding member 6 and the end portion of the lead holding member 6 is reduced, and it is possible to spread smoothly. Of course, also in this second example, the cross-sectional shape of the insertion hole 9 of the lead protection tube 5 is
Although the insertion hole has a triangular shape that is slightly larger than the outer shape of the core holding member 6, as shown in FIGS. 12 and 13, the insertion hole of the core protection tube 5 is formed into a circular shape and the inside of the holding ring 11 is formed. The vertical groove 11b may be formed and the protrusion 13 of the core holding member 6 may be engaged with the vertical groove 11b. By the engagement, the rotation of the lead holding member 6 with respect to the lead protection tube 5 can be prevented.
A general pipe-shaped material can be used as the core protection tube, and the cost can be reduced.

A third example will be described with reference to FIG. It is another example of preventing rotation of the lead holding member 6 with respect to the lead protection tube.
Inside the core protection tube 14 having a hexagonal cross section,
A core holding member 6 having a triangular cross section is inserted. Further, recesses 14a are formed on arbitrary side surfaces (two locations in this example) of the lead protection tube 8 to more reliably prevent the lead holding member 6 from rotating.

Next, a fourth example will be described with reference to FIG. This is an example in which the holding ring is formed as a holding portion 4b on the inner surface of the tip member 4, and the holding portion 5a is also formed on the lead protection tube 5 itself. By integrally forming the holding portion on the tip member 4 and the lead protection tube 5 in this manner, the number of parts can be reduced and the assembling can be facilitated, so that the cost of the product can be reduced. It is a thing.

A fifth example will be described with reference to FIGS. As shown in FIG. 17, at both inner ends of the lead protection tube 5 fixed to the tip of the tip member, a surface portion 15a perpendicular to the side surface of the lead protection tube 5 and three places on the vertical surface portion 15a are provided. The retaining ring 15 formed with the engaging portion 15b is press-fitted. Between each of the fixing rings 15, a core holding member 6 in which a slit 8 that is substantially similar to that of the first example is formed is arranged with its forward and backward movement restricted. In addition, the core holding member 6
The three corners 6a are attached so as to be locked to the respective locking portions 15b, and are held inside the lead protection tube 5 without wobbling even when the diameter is reduced to the minimum.

Further, as shown in FIG. 19, the lead holding member 6
Inclined surfaces 16 are formed along the inner sides of both ends of the core, and the locking portion 15 similar to the holding ring 15 is formed on the core holding member 6.
b, and the corner portion 6 of the lead holding member 6 is formed on the locking portion 15b.
You may lock a. By forming inclined surfaces 16 on the inner surfaces of both ends of the lead holding member 6, the cross section is circular (see FIG.
1 to 24))) can be attached. A protrusion 18 is formed on a part of the end of the circular core holding member 17, and a vertical groove 19 is formed on the holding ring 19.
A is formed, and the projection 18 is engaged with the vertical groove portion 19a to prevent the lead holding member 17 from rotating with respect to the lead protection tube 5. By forming the inclined surfaces on the lead holding members 6 and 17, it is possible to accurately return to the center of the lead protection tube 5 when the lead holding member contracts in diameter. The holding ring 19 also has a vertical surface portion 19b.

A sixth example will be described with reference to FIGS. 25 and 26.
The claw portions 21 are formed at equal intervals on both ends of the lead protection tube 20, and the claw portions 21 are formed in a U shape so as to be bent toward the inner side of the lead protection tube 20. Then, similar to the previous example, the corner portion 6a of the lead holding member 6 having a substantially triangular cross section is locked by the claw portion 21 to prevent the lead holding member 6 from falling out of the lead protecting tube 20 and back and forth with respect to the lead protecting tube 20. It is a thing.

Next, the operation of the fifth and sixth examples will be described. When the core L having a relatively large core diameter is inserted into the core holding members 6 and 17 due to the dispersion of the core L, the core holding members 6 and 17 are evenly distributed along the vertical surface portions 15a, 19b and 20a, and The core protection tube 20 expands radially without being restricted. Also, the retaining rings 15, 19
Alternatively, since the holding portion of the core holding member 6 is a substantially right-angled step, even when the diameters of the core holding members 6 and 17 are reduced, the diameter of the core holding member is reduced along the substantially right-angled step. Return to the original position. Further, since the front and rear of the core holding members 6 and 17 are regulated by the stepped portion, the core holding member (also the residual core) does not move back and forth even at the time of writing the residual core, so that the writing can be performed without a feeling of strangeness. it can.

A seventh example will be described with reference to FIGS. 27 and 28.
It shows another example of the sixth example, in which inclined surfaces 16 are formed at both ends of the core holding member 6, and the inclined surfaces 16 are used for the core protection tube 20.
This is an example in which it is locked to the claw portion 21 formed on. still,
The slanted surface of the claw portion 21 that comes into contact with the slanted surface 16 may be formed so that the slanted surfaces may abut each other. As shown in FIGS. 29 and 30, the claw portion 21 may be provided at the end of the lead protection tube 20. It may be formed further inside. By forming the claw portion 21 inside the lead protection tube 20, the appearance is improved and the writing can be performed without a feeling of strangeness. Further, similarly to the previous example, even when the diameter of the core holding member 6 is reduced, the diameter of the core holding member is reduced along the substantially right-angled step portion and returns to the original position. Furthermore, FIG.
32. As shown in FIG. 1 and FIG. 32, the claw portion 23 may be formed at an appropriate position of the holding ring 22 to hold the core holding member 6 having a square cross section. As a method of forming the holding ring 22, as shown in FIGS. 33 to 35, the plate-like object P on which the claw portions 23 are formed is formed into a circular shape (see FIG. 34), and then the claw portions 23 are formed inside. By bending it in one direction (see FIG. 35) or by forming a projection 25 that becomes a claw in advance inside the cylindrical object (holding ring) 24, and then cutting one end portion into a conical shape, There is a method of exposing the portion 25 to form the claw portion 26 (see FIGS. 36 and 37). In the examples shown in FIGS. 36 and 37, the core holding member 6 is formed with inclined surfaces at both ends.

Further, as shown in FIGS. 38 and 39, the inclined surface 28 is formed on the outer periphery of the lead holding member 27, and the inclined surfaces 16 are formed on both ends of the lead holding member 6, and the lead holding member is also formed. You may form the protrusion part 29 in the inner one end of 5. As in the previous example, the lead holding member 6 can be expanded without being restricted by the lead protection tube 5, and the protrusion 29 can prevent the lead holding member 6 from rotating.

Various examples have been described above. However, the inner surface of the core holding member of the present invention is described in the prior art as an open flat plate 3-90.
By forming the inner surface treated portion as shown in No. 992, it is possible to provide a better sharp pencil.

[0021]

The present invention provides a sharpening pencil in which a lead-out mechanism is arranged in the barrel and a lead protection tube is placed at the tip of the barrel. Since the core holding member formed in an outer shape slightly smaller than the inner shape is loosely inserted, and the rotation preventing means for preventing the rotation of the core holding member is arranged inside the core protection tube, the core diameter is relatively large. Even if it is, the lead holding member can be expanded without being regulated, and therefore, the lead holding member can be restored with time.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an example in which a residual core holding means of the present invention is attached.

FIG. 2 is a vertical sectional view showing an embodiment of the present invention.

3 is a cross-sectional view taken along the line AA in FIG.

FIG. 4 is a vertical cross-sectional view showing the state before inserting the lead in FIG.

5 is a sectional view taken along line BB in FIG.

FIG. 6 is a longitudinal sectional view of a main part showing another example of the present invention.

FIG. 7 is a vertical cross-sectional view showing another example of the present invention.

FIG. 8 is a vertical cross-sectional view showing another example of the present invention.

9 is a sectional view taken along line CC in FIG.

FIG. 10 is a perspective view showing another example of the lead holding member.

FIG. 11 is a vertical cross-sectional view showing another example of the present invention.

FIG. 12 is a vertical cross-sectional view showing another example of the present invention.

13 is a cross-sectional view taken along the line DD in FIG.

FIG. 14 is a cross-sectional view showing another example of the lead protection tube.

FIG. 15 is a vertical sectional view showing another example of the present invention.

FIG. 16 is a vertical sectional view showing another example of the present invention.

17 is a cross-sectional view taken along the line EE in FIG.

FIG. 18 is a perspective view showing the lead holding member in FIG. 16.

FIG. 19 is a vertical sectional view showing another example of the present invention.

20 is a cross-sectional view taken along line FF in FIG.

FIG. 21 is a vertical sectional view showing another example of the present invention.

22 is a cross-sectional view taken along the line GG in FIG.

23 is a sectional view taken along line HH in FIG.

FIG. 24 is a perspective view showing the lead holding member in FIG. 22.

FIG. 25 is a vertical cross-sectional view showing another example of the present invention.

FIG. 26 is a view on arrow I in FIG. 25.

FIG. 27 is a vertical sectional view showing another example of the present invention.

FIG. 28 is a view on arrow J in FIG. 27.

FIG. 29 is a vertical cross-sectional view showing another example of the present invention.

30 is a sectional view taken along line KK in FIG. 29.

FIG. 31 is a vertical sectional view showing another example of the present invention.

32 is a sectional view taken along line MM in FIG. 31.

FIG. 33 is a front view showing the processing method of the lead holding member in FIG. 31.

34 is a front view showing the processing method of the lead holding member in FIG. 31. FIG.

FIG. 35 is a front view showing the processing method of the lead holding member in FIG. 31.

FIG. 36 is a vertical cross-sectional view showing another example of the present invention.

37 is a cross-sectional view taken along the line NN in FIG. 36.

FIG. 38 is a vertical cross-sectional view showing another example of the present invention.

39 is a cross-sectional view taken along line OO in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Chuck ring 3 Chuck 4 Tip member 4a Core protection tube part 4b Holding ring part 5 Core protection tube 5a Holding part 5b Inclined surface 6 Core retention member 6a Inclined surface (Round) 7 Core detent 8 Slit 9 Insertion hole 10 Gap 11 Holding ring 11a Sloping surface (roundness) 11b Vertical groove 12 Vertical surface 13 Projection 14 Core protection tube 15 Holding ring 15a Vertical surface 15b Locking portion 16 Inclined surface 17 Core holding member 18 Projection 19 Holding ring 19a Vertical Groove portion 19b Vertical surface portion 20 Core protection tube 20a Vertical surface portion 21 Claw portion 22 Holding ring 23 Claw portion 24 Cylindrical object (holding ring) 26 Claw portion 27 Core holding member 28 Inclined surface 29 Protruding portion L core

Claims (5)

[Claims] 1. A sharp pencil in which a lead-out mechanism is arranged in the barrel and a lead protection pipe is placed at the tip of the barrel, and the inside of the lead protection pipe is slightly smaller than the inner shape of the lead protection pipe. A sharp pencil characterized in that a lead holding member formed in a small outer shape is loosely inserted, and rotation preventing means for preventing rotation of the lead holding member is arranged inside the lead protection tube. 2. The sharp pencil according to claim 1, wherein a slit is formed in a longitudinal direction of the core holding member and a cross section of the core holding member is formed into a non-circular shape. -Puppencil. 3. A sharp pencil having a lead-out mechanism arranged in the barrel and a lead protection tube at the tip of the barrel, which is slightly inside the lead protection tube from the inner shape of the lead protection tube. A sharp pencil in which a core holding member formed in a small outer shape is loosely inserted, and the inner shape of the core protection tube and the outer shape of the core holding member are formed in a non-circular shape. 4. A sharp pencil having a lead-out mechanism arranged in the barrel and a lead protection tube at the tip of the barrel, which is slightly inside the lead protection tube from the inner shape of the lead protection tube. A core holding member formed in a small outer shape is loosely inserted, and a holding portion for preventing the core holding member from falling off is arranged on the inner surface of the core protection tube, and at least one end of the core holding portion or the core holding member. A sharp pencil characterized in that a substantially vertical step portion is formed in the portion, and the lead holding member is held by the step portion. 5. A sharp pencil having a lead-out mechanism arranged in the barrel and a lead protection tube at the tip of the barrel, which is slightly inside the lead protection tube from the inner shape of the lead protection tube. A core holding member formed in a small outer shape is loosely inserted, and a holding portion for preventing the core holding member from falling off is arranged on the inner surface of the core protection tube, and at least one end of the core holding portion or the core holding member. An inclined surface is formed on the portion, and the core holding member is held by the inclined surface.
Pupencil.