JPH08318694A - Touch-delivery type mechanical pencil - Google Patents

Abstract

PURPOSE: To provide a mechanical pencil capable of performing the recovery of a core, when the core is projected out of the tip excessively, in a state of the shaft sleeve just as held by a user, and preventing the core from being broken and prolong the life of a core securing chuck at low cost. CONSTITUTION: The touch-delivery type mechanical pencil having a mechanism for fastening a core fixture chuck to a fastening part through the point contact of a projection spherical surface about the outer periphery of a grasp part is provided with an engaging part 3c elastically shiftable in the diameter- contraction direction at the rear end of the core fixture chuck 3, on the other hand, provided with an engaging part 19b extending to the rear direction of a delivering body 16 having a holding chuck 18 at its center and elastically shiftable in the expansion direction at its rear end. The engaging part 19b elastically engages with the engaging part 3c at the rearmost position of the delivering body 16 and, by the engaging operation, the core fixture chuck 3 is allowed to slightly advance so as to release the grasp condition of the core, further, a coil spring 12 is urged to the rear end of a chuck case 2, thereby permitting the core fixture chuck 3 and chuck case to be retractable at least an appropriate writing pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical pencil which does not require knocking at the rear end one by one when the lead is worn out during writing, or a touch finger portion provided at the tip of the shaft while maintaining the writing state. The present invention relates to an improvement of a touch-finger-feeding type mechanical pencil that allows a required amount of lead to be drawn by adding a light pulling backward with a fingertip and releasing it.

[0002]

2. Description of the Related Art As a conventional example, a touching finger which has a sufficient core holding force for writing by a structure in which a lead fixing chuck is tightened with a ball, but requires only a small force to pull out the lead from the chuck. Feed-out type mechanical pencils are known. This one has a small ball attached to the fixed core chuck, which is poor in assemblability and is expensive. Also, there is no need to bother knocking out the trailing end and feeding out the lead one by one due to the consumption of the lead caused by writing, but a slider that integrally has a tip pipe and a holding chuck moves backward with respect to the mouthpiece as the lead wears. Therefore, if external force is applied to the tip pipe, there is a problem that the core is unintentionally extended. Especially, this occurs when the tip pipe is applied to a ruler to draw a wire. If the core is unintentionally extended long, it is necessary to release the grip of the core by knocking the rear end and advancing the chuck as an operation of returning the core. Therefore, it is necessary to re-grip the barrel, which is troublesome. Also, during writing, when excessive writing pressure is applied to the tip of the lead, core breakage or core slippage occurs in the grip of the core fixing chuck, resulting in wear of the grip or clogging by core powder Wake up. The grip portion is usually formed with a minute screw-shaped protrusion. In particular,
When the core fixing chuck is made of a resin molded product at a low cost, a significant problem occurs. Further, there is a problem that plastic deformation and wear of the tightening portion that comes into contact with the ball are likely to occur.

Further, the applicant of the present application discloses a touch-fing type mechanical pencil in Japanese Utility Model Publication No. 64-1107.
According to this, the joining cylinder 6 is press-fitted and fixed to the shaft cylinder 7 on the outer periphery of the front end portion of the chuck case 2, and the shaft joint 8 is screwed to the inner diameter portion of the front end of the joining cylinder 6. A screw portion is formed on the outer diameter portion of the front end of the shaft coupling 8, and a cap 10 having a tip pipe 9 fixed thereto is screwed onto the screw portion. Shaft joint 8
A center portion 14 of the feeding body 13 fitted around the holding chuck 12 is provided inside the inner portion of the feeding body 1.
3 has a piece portion 15 projecting outward from this center portion, and a short tubular touch finger portion 16 is formed at the tip thereof. Feeding body 13
The piece portion 15 penetrates a slit 17 provided in the axial direction from the tip of the shaft coupling 8 toward the rear, and exposes the touching finger portion 16 to the outer peripheral portion of the shaft coupling 8. In the case where the lead is normally fed out separately from the finger-feeding, the lead case 1 connecting to the knock operation portion compresses the coil spring 20 interposed between the lead pipe 1 and the joining cylinder 6, and the chuck case 2 is attached to the shaft joint. The lead fixing chuck 4 is advanced until it abuts against the rear end of the lead 8, and then the lead fixing chuck 4 is opened to feed the lead. When the knock is released, the chuck case 2 retreats, but at that time, it is necessary to retreat with the lead fixing chuck 4 left open. Therefore, the lead guide 1 needs to be configured to frictionally engage the outer circumference of the chuck case 2 with a force stronger than that of the coil spring 5. As shown above,
The conventional example has a drawback that the threaded portion of the shaft joint 8 is provided with the slit 17 and is easily deformed. Therefore, the feeding body 1
The sliding failure of No. 3 and the loosening of the mouthpiece 10 are likely to occur. Therefore,
In fact, these parts are made of metal products, and the cost of parts is relatively high. In addition, the conventional example has a large number of parts and a large number of screwed portions, and thus there is a problem of further cost increase.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention is to eliminate the troublesome point in the above operation. In addition, we have improved the structural defects of the conventional mechanical pencil of the toe-feeding type,
Most of the main members can be made into resin, and by omitting the members, it is possible to provide them at low cost due to a significant cost reduction.

[0005]

In order to achieve the above-mentioned object, a finger-feeding type mechanical pencil of the present invention is a chuck case having a projecting spherical surface integrally formed with a core fixing chuck 3 on the outer periphery of a grip portion. 2 It has a sufficient core holding force for writing due to the structure that is fastened to the tightening part at the tip,
A mechanical pencil that requires only a small force to pull out the lead from the chuck, and includes a barrel 1, a base 13,
Main members of the feeding body 16 and the touching finger portion 20 are formed as synthetic resin molded products, respectively, and a mouthpiece 13 having a guide slit 15 formed slightly forward of the center of the shaft side surface is screwed or press-fitted into the tip of the barrel 1. A fixed feeding member 16 which is fixed and fits in the guide slit 15 and is slidable is fitted in the base 13, and a holding chuck 18 is provided at the center of the feeding member 16 and a member provided on the feeding member 16. A ring-shaped touch finger portion 20 that has a protrusion 20a that engages with the stop groove 19c by elastic deformation and that is integrally interlocked with the payout body 16 is provided in the base 1.
3 is exposed to the outside of the touch finger portion 20, and a coil spring 21 is interposed between the touch finger portion 20 and the base 13 inside the touch finger portion 20 so that the touch finger portion 20 is pressed forward.

Further, a locking portion 3c which is elastically displaceable in the diameter reducing direction is provided at the rear end of the lead fixing chuck 3, while the feeding body 1 is provided.
6, a locking portion 19b is provided at the rear end, which is elastically displaceable in the expanding direction, and the locking portion 19b elastically engages with the locking portion 3c at the last retracted position of the feeding body 16. With
Due to the engaging action, the lead fixing chuck 3 is slightly advanced to release the gripped state of the lead.

Further, a coil spring 12 is biased to the rear end of the chuck case 2 so that the lead fixing chuck 3 and the chuck case 2 are retracted by appropriately pressing or more.

[0008]

1 to 3 show an embodiment of the present invention. First, an eraser stopper attached with an eraser is fixed to the rear end hole of the core case 9 that appropriately protrudes from the rear end of the shaft cylinder 1, and a knock cover is detachably fitted to the outer periphery of the rear end of the core case 9. It (Not shown)

Further, a flange portion 9a is formed at the tip of the lead case 9 and is prevented from moving backward by the step portion 1b in the shaft cylinder 1, and a lead guide 10 is formed at the tip, and the lead guide 10 has an outer periphery at the tip. Is provided with a circumferential groove portion 11a, and a projecting locking portion 11 is provided behind the groove portion 11a. Further, a slit portion 6 is formed on the rear side surface of a chuck case 2 described later, an axial window portion 8 is bored in the outer periphery orthogonal to the slit portion 6, and the rear end of the window portion 8 has a step portion 8a. It has a closed shape. Further, an inner protruding portion locking portion 7 is provided on the inner side surface. The core guide 10 is elastically fitted from the rear end hole of the chuck case 2, the locking portion 11 is fitted into the window portion 8 and the locking portion 11 abuts on the stepped portion 8a, and the core guide 10 is attached to the chuck case. It is possible to move backward with respect to 2 and it is prevented from coming off.
(Note that, in the cross section shown, the locking portion 11 and the window portion 8 are not visible and are therefore shown in phantom lines)

A spacer 22 is provided so as to face the stepped portion 1a of the shaft cylinder 1, the rear end of the chuck case 2 abuts against the inner stepped portion 22a, and the core case 9 has the collar portion 9a.
And the rear end of the spacer 22 are normally urged rearward by the coil spring 12.

By the way, a fastening portion 2a is integrally formed at the tip of the chuck case 2. A front end inner diameter portion of the tightening portion 2a has a tapered shape, and a fixed chuck 3 in which spherical surfaces 4 and 4 contacting the tapered surface are integrally formed on an outer peripheral surface of the grip portion 3a is internally provided. The coil spring 5 is interposed between the tightening portion 2a and a step formed on the rear side of the fastening portion 2a to urge the rearward direction. The core fixing chuck 3 is made of a synthetic resin molded product having excellent elasticity and high abrasion resistance, and is constructed by combining two split cylindrical bodies. Further, an elastic piece 3b that faces the front is formed on the outer periphery of the rear end portion of the lead fixing chuck 3, and a locking portion 3c having a rounded or mountain-shaped projecting peripheral surface is formed at the tip of the elastic piece 3b. The piece 3b and the locking portion 3c are slidably fitted in the slit portion 6 of the chuck case 2. The locking portion 3c is elastically displaceable in the diameter reducing direction with a weak force. The rear end portion of the elastic piece 3b and the engaging portion 3c is integrally formed with the rear end of the core fixing chuck 3, but is fixed as a separate member to the rear end of the core fixing chuck 3 in manufacturing. Sometimes.

A liquid crystalline aromatic polyester resin is one of suitable materials for the core fixing chuck. The liquid crystalline aromatic polyester resin is generally a thermotropic liquid crystal polymer or simply a liquid crystal polymer (Liquid Cry).
It is a kind of resin called "stall line polymer (LCP)", and has a unique structure that is not found in conventional resins because the molecular chain has a rigid structure. Therefore, various characteristics of the liquid crystalline aromatic polyester resin can be sufficiently reflected in the merit as a chuck. That is, for example, the surface hardness is high, the abrasion resistance is excellent, the mechanical strength is high, and the mechanical strength is increased particularly in the thin-walled molded product. In addition, it has a high elastic modulus and is excellent in heat resistance and chemical resistance Molding can be performed with conventional thermoplastic resin injection molding equipment because it has a small mold shrinkage, excellent dimensional stability, excellent vibration absorption characteristics, excellent flowability and less burr, and excellent moldability. It is possible.

When writing pressure is applied to the core, the spherical surfaces 4 and 4 come into point contact with the tightening portion 2a and the core fixing chuck 3 is clamped by the wedge effect to retain the core, but when the core is pulled forward,
By setting the spring force of the coil spring 5 to be weak, it is possible to use a small force of about several grams. By the way, the chuck case 2 is formed of a resin molded product, and the conventional product is expensive because the tightening portion 2a is formed of metal and the processing is complicated.
Further, if it is made of resin, there is a problem that durability is insufficient due to plastic deformation, abrasion, etc., but for the reason described later, a chuck case integrated with a tightening portion has become possible.

Further, a screw portion is formed on the inner diameter portion of the front end of the shaft cylinder 1, and a resin mouthpiece 13 having a tip pipe 14 fixed thereto is screwed to a rear portion of the collar portion 13a. or,
A window portion 13b is formed in the rear outer peripheral portion of the rear portion.
Further, the base 13 may be press-fitted into the outer diameter portion of the front end of the barrel 1. Further, the tip pipe may be integrally formed with the mouthpiece 13. Further, a guide slit 15 is bored in the front axial side surface of the collar portion 13a of the mouthpiece 13, and a guide groove 15a is formed so as to communicate with the guide slit 15 and reach the rear end at the inner peripheral portion of the rear portion. The window 13a is provided coaxially with the guide groove 15a.

Further, a payout body 16 is slidably fitted inside the mouthpiece 13, and a central portion 1 of the payout body 16 is fitted.
7, a holding chuck 18 is fixedly provided, and a locking groove 19c is formed at a predetermined position corresponding to the guide slit 15 on the outer periphery of the front end of the engaging piece 19 integrally extending to the rear end side. The joint piece 19 is fitted in the guide slit 15 and is slidable. Further, at the rear end of the engagement piece 19, an elastic portion 19a which is elastically displaceable at a position corresponding to the window portion 13b.
On the inner side of the elastic portion 19a, there is formed a locking portion 19b in the shape of a rounded groove or a mountain shape corresponding to the locking portion 3c. Further, there is provided a space corresponding to the amount of extension by knocking operation between the tip of the fastening cylinder 2a and the facing surface when the delivery body 16 is at the frontmost position of the mouthpiece 13.

Further, the touching finger portion 20 is made of a resin having a ring shape, and a projection portion 20a is formed at a portion corresponding to the locking groove 19c on the inner peripheral portion of the substantially tip end thereof. The finger 20 is the base 1
3, the protrusion 20a is elastically fitted to the outside of the locking groove 19
The touching finger portion 20 and the feeding body 16 are integrally interlocked with each other by fitting into c and engaging each other. Also, the rear end of the touching portion 20 and the base 1
An interval for extending the finger is provided between the contact point 3 and the contact point 3.

Further, inside the touching finger portion 20, a coil spring 21 is interposed between the touching finger portion 20 and the base 13 to bias the touching finger portion 20 in a forwardly pressed state. The spring force of this spring may be larger than the force for pulling out the lead from the lead fixing chuck 3, and can be set to about 10 to 20 grams.

As shown in FIG. 1, the lead fixing chuck 3 is provided.
It is necessary that the engaging portion 3c and the engaging portion 19b at the rear end of the feeding body 16 face each other on the coaxial line. For this reason, ribs and grooves are provided between the outer peripheral portion of the chuck case 2 and the inner peripheral portion of the die 13 to prevent the chuck case 2 from freely moving backward and forward. (Not shown) With the above configuration, the feeding body 1 for the lead fixing chuck 3
The frontward retreat of 6 disengages the locking portion 3c and the locking portion 19b. By the way, the engagement / disengagement force is weak, but it is slightly stronger than the biasing force of the coil spring 5, and the coil spring 2
It is appropriately weaker than the biasing force of 1.

[0019]

The feeding body 16 can be slid rearward by pulling the external touching finger portion 20 gently backward with a finger and bringing the engaging piece 19 along the guide slit 15 and the guide groove 15a. Then release the finger and hold the chuck 18
Holds the lead and returns to the front so you can feed the lead. The amount of extension is a value of an interval with an appropriate gap before the rear end of the touching finger portion 20 comes into contact with the flange portion 13a of the facing die 13. (See Fig. 2)

Further, in the state shown in FIG. 2, the engaging portion 3c of the lead fixing chuck and the engaging portion 19b of the feeding body are about to be engaged, and the rear end of the touching finger portion 20 is in contact with the collar portion 13a. The locking portion 3c is engaged with the locking portion 19b by the protrusion effect of the rounded or tapered (mountain-shaped) peripheral surfaces of the locking portions,
The lead fixing chuck 3 is slightly advanced to release the lead grip. Therefore, if the tip of the lead is pressed in that state, the lead can be immersed in the tip pipe 14. (See Figure 3)

When the lead is normally fed out, the rear end of the knock cover may be knocked, and it is interposed between the stepped portion 9a at the tip of the lead case 9 connected to the knock cover and the rear end of the spacer 22. While compressing the coil spring 12, the lead guide 10 advances the fastener 2a integrated with the chuck case 2 (the groove portion 11a of the lead guide 10 is engaged with the locking portion 7 of the chuck case 2 so that the lead The case 9 and the chuck case 2 are interlocked with each other. In this state, since the chuck case 2 is prevented from moving forward, the groove portion 11a elastically moves over the locking portion 7 and moves forward, and the tip of the lead guide 10 comes into contact with the rear end of the lead fixing chuck 3 to bring the lead fixing chuck into contact. 3 is opened and the lead is fed out.

Next, when the rear end knock of the knock cover is released, since the engaging portion 7 is frictionally engaged with the outer periphery of the lead guide 10, the lead fixing chuck 3 and the lead case 9 together with the lead case 9 keep the gripping portion open. 2 is retracted, the rear end of the chuck case 2 contacts the inner step portion 22a of the spacer 22 and is prevented from retracting, only the lead case 9, that is, the lead guide 10 is retracted and the locking portion 11 is opened by the window portion. The step portion 8a of 8 is abutted, and the locking portion 7 is fitted into the groove portion 11a. by the way,
In the above embodiment, the groove portion 11a that engages with the locking portion 7 is provided at one location, but it may be provided at two locations at the forward movement position and the backward movement position of the lead guide 10.

Also, during writing, when excessive writing pressure is applied to the tip of the lead, the lead fixing chuck 3, the chuck case 2 and the spacer 22 compress the coil spring 12 and retract, so that the lead is inside the tip pipe 14. Immerse yourself in. That is,
By fixing the load that the core sinks into the tip pipe within the normal writing pressure range of about 400 g to 800 g, a resin core fixing integrally having a resin fastening part and a spherical surface that makes point contact with the fastening part Even with a chuck, it is possible to prevent plastic deformation and wear of the tightening portion and the spherical surface.

[0024]

As described above, according to the present invention, when the lead is extended for a long time, the lead can be operated by operating the button with a finger while holding the lead, so that the troublesome operation of the related art can be eliminated. . In addition, since there is no notched slit up to the tip of the conventional shaft coupling, structural defects such as poor sliding of the fingertip portion and loosening of the screwed portion are eliminated. Further, the shaft cylinder, the base, the feeding body, and the touching finger portion are each formed as a synthetic resin molded product, and the simplification of the members is achieved, so that the cost can be greatly reduced.
Further, although there is a problem of quality in the conventional complicated metal working and screwing part due to processing variations, since the present invention can be formed by resin molding using a mold, there is no variation between members and the quality is stabilized. Also, if excessive writing pressure is applied to the tip of the lead, the lead will sink into the tip pipe, so the lead will not be broken and the lead gripping part of the lead fixing chuck, the spherical surface, and the tightening part will not be burdened with improved durability. It is possible to form the expensive core fixing chuck and the tightening portion with an inexpensive resin molded product.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a finger-feeding type mechanical pencil according to an embodiment of the present invention, in which a part is half-sectioned.

FIG. 2 is a vertical cross-sectional view corresponding to FIG. 1, showing a state in which a touching finger portion is pulled to extend a lead.

FIG. 3 is a vertical cross-sectional view showing a state in which the touching finger portion is finally retracted and the grip of the lead fixing chuck is released.

[Explanation of symbols]

 1 Shaft 1a Step 1b Step 2 Chuck case 2a Tightening 3 Core fixing chuck 3a Grip 3b Elastic piece 3c Locking part 4 Spherical 5 Coil spring 6 Slit 7 Locking 8 Window 8a Step 9 core 9a Collar part 10 Core guide 11 Locking part 11a Groove part 12 Coil spring 13 Base 13a Collar part 13b Window part 14 Tip pipe 15 Guide slit 15a Guide groove 16 Feeding body 16a Step portion 17 Center part of feeding body 18 Holding chuck 19 Engagement One piece 19a Elastic part 19b Locking part 19c Locking groove 20 Touch finger part 20a Projection part 21 Coil spring 22 Spacer 22a Inner step part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiichi Kobayashi 2-5-12 Irie, Kanagawa-ku, Yokohama, Kanagawa Mitsubishi Pencil Co., Ltd. Yokohama Office

Claims (4)

[Claims] 1. A structure in which the lead-fixing chuck 3 is integrally formed on the outer periphery of the holding portion and is fastened to a tightening portion at the tip of the chuck case 2 by a projecting spherical surface has sufficient lead holding power for writing. It is a mechanical pencil that requires only a small force to pull out the lead from the chuck, and the main members of the barrel 1, the mouthpiece 13, the feeding body 16, and the touch finger portion 20 are formed as synthetic resin molded products, A base 13 having a guide slit 15 drilled slightly in the center of the side surface of the shaft is fixed to the tip of the barrel 1 by screwing or press fitting, and is inserted into the guide slit 15 inside the base 13 and is slidably fed out. The body 16 is fitted, a holding chuck portion is provided at the center of the feeding body 16, and a locking portion that engages with the locking portion provided on the feeding body 16 by elastic deformation is provided. In a row A moving ring-shaped touch finger portion 20 is exposed to the outside of the mouthpiece 13, and a coil spring 21 is interposed between the touch finger portion 20 and the mouthpiece 13 inside the touch finger portion 20. In a finger-feeding type mechanical pencil in which the portion 20 is pressed forward, a locking portion 3c which is elastically displaceable in the diameter reducing direction is provided at the rear end of the core fixing chuck 3, while the feeding body 16 is provided. A locking portion 19b that extends rearward of the locking member 19b and is elastically displaceable in the expansion direction at the rear end, and the locking portion 19b elastically engages with the locking portion 3c at the last retracted position of the feeding body 16. The lead-fixing type mechanical pencil is characterized in that the lead fixing chuck 3 is slightly advanced by the engaging action thereof to release the gripped state of the lead. 2. The engaging portion 3c of the lead fixing chuck 3 is provided in a protruding shape, and the guide slit 15 is provided inside the base 13.
Feeding body 1 having engaging piece 19 slidably fitted in
6. The touch-finger-sharpening sharpener according to claim 1, further comprising an elastic portion 19a mounted on the rear end of the engaging piece 19 and a groove-shaped engaging portion 19b provided inside the elastic portion 19a. Pencil. 3. The coil spring 12 is urged to the rear end of the chuck case 2 so that the lead fixing chuck 3 and the chuck case 2 are appropriately retracted by pressing or more, and The mechanical pencil that is described in 2. 4. A lead case 9 which is prevented from moving backward with respect to the barrel 1.
And the spacer 2 fixed to the rear end of the chuck case 2.
Coil spring 12 is urged between 2 and
When the core protruding from the tip of the tip pipe 14 of No. 3 is appropriately applied with a load more than the writing pressure, the lead fixing chuck 3 and the chuck case 2 are retracted so that the lead is retracted into the tip pipe 14. The touch-sensitive stick-out type mechanical pencil according to claim 3, which is characterized in that.