JPH07323693A - Finger contact feeding mechanical pencil - Google Patents

Abstract

PURPOSE:To improve the structural disadvantage of a finger contact feeding mechanical pencil, largely reduce the cost thereof and regulate the discharging size of a lead substantially constantly. CONSTITUTION:A base 13 having a guide slit 15 provided at a shaft side face is mounted at a sliding tube 22, and the tube is so mounted at the end of a barrel 1 as to be axially moved in a suitable range by being pressed by a coiled spring 12. A feeder 16 having a guide slit 15 and a slidable locking piece 19 is provided in the base, and a holding chuck 18 is provided at its center. A ringlike finger contact part 20 engaged with the piece 19 and cooperated integrally with the feeder 16 is exposed out of the base 13, a coiled spring 21 is interposed between the part 20 and the base 13 to set the part 20 to a forwardly pressed state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when the lead is worn out during writing, has a touching portion provided at the tip of the shaft with the fingertip lightly pulling backward with the fingertip and releasing it. The present invention relates to an improvement of a touch-finger-feeding type mechanical pencil that allows the required amount of lead to be fed.

[0002]

2. Description of the Related Art As a conventional example, 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,
A base 10 to which the tip pipe 9 is fixed is screwed here. A central portion 14 of a feeding body 13 fitted around a holding chuck 12 is provided inside the shaft coupling 8, and the feeding body 13 projects a piece 15 outward from the central portion and has a tip end thereof. A short tubular touch finger 16 is configured. The piece portion 15 of the payout body 13 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, core guide 1
Must be configured to frictionally engage the outer circumference of the chuck case 2 with a stronger force than the coil spring 5. As described 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, sliding failure of the payout body 13 and loosening of the mouthpiece 10 are likely to occur. Therefore, in reality, these members are provided as metal products, and the cost of the members 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.

[0003]

SUMMARY OF THE INVENTION Therefore, the present invention improves the structural defects of the conventional example, allows most of the main members to be made of resin, and omits the members so that the cost can be greatly reduced and the cost is low. It intends to provide a mechanical pencil that extends the fingers. Further, in the conventional example, when the lead is projected longer than necessary from the tip of the tip pipe, the knock cover at the rear end of the shaft cylinder is knocked to release the lead gripping state of the lead fixing chuck, and the tip of the lead is also released. Must be pressed to immerse the core in the tip pipe. Therefore, it is necessary to re-grip the shaft cylinder, which is inconvenient. In addition, there is the annoyance of re-inserting the core. The present application aims to solve that problem as well.

[0004]

In order to achieve the above object, the finger-feeding type mechanical pencil of the present invention has a sufficient core holding force for writing due to a structure in which a lead fixing chuck is tightened with a ball. However, it is a mechanical pencil that requires only a small force to pull out the lead from the chuck, and includes a shaft cylinder, a base, a feeding body, a finger portion, a sliding tube,
Each core case is formed as a synthetic resin molded product, a base with a guide slit formed slightly forward of the center of the shaft side is attached to the tip of the sliding tube, and the sliding tube moves axially within an appropriate range with respect to the barrel. Install a feeding body with a locking piece that fits in the guide slit and is slidable inside the mouthpiece, and install a holding chuck at the center of the feeding body and engage with the locking piece. Then, the ring-shaped touching finger portion that is integrally linked with the feeding body is exposed to the outside of the mouthpiece, and inside the touching finger portion, the coil spring is interposed between the touching finger portion and the mouthpiece, and the touching finger portion is A pressing case is formed on the front side, and a locking case is provided on the rear side of the chuck case for tightening the core fixing chuck with a ball, and the core case is provided so as to interlock with each other in a frictionally engaged state. Behind the sliding tube while being prevented from moving backward against the shaft cylinder A coil spring is urged between the core case and the core case, and the core fixing chuck, the chuck case, and the mouthpiece are integrated with the sliding tube relative to the shaft cylinder so as to move back and forth in an appropriate range relative to the shaft cylinder. .

[0005]

1 to 3 show an embodiment of the present invention. First, an eraser is fixed to a 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. (Not shown) Further, the rear end side surface of the shaft cylinder 1 has a slit portion 23a including a slit 23a, a small slit block 23b having a taper portion 24, and a step portion 25 having a slit 23c. At the same position, the protrusion 26a is formed at the front end on the side surface of the lead case 9 at the same position.
A rib-shaped bulging portion 26 having
Is fitted into the slit 23a and elastically deforms the tapered portion 24 so that the rear end of the protrusion 26a has the slit 23c at the step 2
The core case 9 is secured to the rear of the barrel 1 by coming into contact with the shaft 5. Further, a clip is integrally provided on a side surface of the knock cover, and a groove is provided on one side of a hole portion to be fitted into the core case 9, and a rib-shaped bulging portion 26 is fitted therein. The core case 9 and the barrel 1 are integrated in the rotational direction.
(Not shown)

A lead guide 10 is integrally formed at the tip of the lead case 9, and a protrusion 11 is provided on the outer periphery of the lead guide 10. Further, a slit portion 7 is formed on the rear end side surface of the chuck case 2, which will be described later, and a locking portion 8 is provided on the side surface portion. The core guide 10 is the chuck case 2
The protrusion 11 and the locking portion 8 engage with each other by fitting into the rear end hole.
Further, the core case 9 is normally urged rearward by the coil spring 12 between the flange portion 9b and a rear end portion 22c of a sliding tube 22 which will be described later. Further, the rear end of the collar portion 9b has the barrel 1
It is in contact with the step portion 1a provided on the. (The flange portion 9b is locked to the step portion 1a by utilizing elastic deformation.) When the step portion 1a is provided, it is not necessary to bring the projection 26a into contact with the step portion 25. (Choose one for your design)

A tightening cylinder 6 is fixed to the tip of the chuck case 2. The inner diameter of the front end of the tightening cylinder 6 is tapered, and the core fixing chuck 3 in which the balls 4 and 4'that contact the tapered surface are fitted in the outer surface recesses is internally provided. The coil spring 5 interposed between the stepped portion formed at the rear end pushes the coil spring 5 rearward. 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. When the writing pressure acts on the core, the balls 4 and 4'roll and the core fixing chuck 3 is tightened by the wedge effect to hold the core. However, when the core is pulled out forward, the spring force of the coil spring 5 is increased. Is set to be weak so that a small force of about several grams is possible. By the way, the chuck case 2 is made of a resin molded product, and the tightening cylinder 6 is made of metal. Originally, the chuck case and the tightening cylinder are integrally formed, but the cost is high if they are made of metal because of complicated processing. If it is made of resin, the durability will be insufficient. The reason why the tightening cylinder 6 is made of metal is that the wear resistance due to rolling of the balls and the rigidity of the tapered portion are taken into consideration. As will be described later, according to the configuration of the present invention, the chuck case 2 and the tightening cylinder 6 can be integrated into a resin molded product.

Further, a window portion 1b is bored on the front side surface of the shaft cylinder 1, and a locking projection 22d provided in a bulging shape on the side surface of a sliding tube 22 described later in the window portion 1b is elastic. Fit in,
The sliding tube 22 is attached to the barrel 1 at an interval B shown in the figure so as to be axially movable. In addition, the cap 13 is inserted into the tip hole of the sliding tube 22.
The shaft portion 13a is screwed.

The mouthpiece 13 is made of resin and has a tip pipe 14 fixed to its tip. The tip pipe may be integrally formed with the mouthpiece 13. A guide slit 15 is formed in the center of the side surface of the mouthpiece 13 slightly forward of the shaft side, and a payout body 16 is slidably fitted inside the mouthpiece 13. The feeding body 16 is provided with a holding chuck 18 fixed to the center thereof, and the guide slit 1 is provided on the outer periphery of the rear end side.
Locking piece 1 having locking groove 19a at a predetermined position corresponding to 5
9 is integrally formed, and the locking piece 19 is a guide slit 15
It can be slidably inserted into. Also, the tightening cylinder 6
An interval corresponding to the amount of extension by knocking operation is provided between the tip of the and the opposing surface when the delivery body 16 is at the frontmost position of the mouthpiece 13.

Further, the touch 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 19a on the inner peripheral portion of the substantially tip end. 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 being fitted in a and engaged with each other. Also, the rear end of the touching portion 20 and the base 1
An interval A is provided between the third flange 13b and the third flange 13b for extending the fingers.

Inside the touch finger portion 20, a coil spring 21 is interposed between the touch finger portion 20 and the base 13 to urge the touch finger portion 20 forward in a 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.

A groove portion 2a and a flange portion 2b are provided on the outer periphery of the center of the chuck case 2, and a cylindrical portion having a slit portion 7 is provided behind the groove portion 2a. On the other hand, a ring-shaped protrusion 22a is formed in the middle of the inner hole of the sliding tube 22.
In the state of being fitted into the chuck case 2, the protrusion 22a is fitted into the groove 2a by mutual elastic deformation.

By the way, on the front outer peripheral portion of the window portion 1a of the shaft cylinder 1, there is provided a pinching portion 1c which is displaced in the diameter reducing direction by finger pressure, and is engaged with the outer peripheral portion of the sliding tube 22 which is in contact with the pinching portion 1c. It is configured so as to prevent axial movement of the sliding tube 22. In the embodiment, the pressing portion 1c having a cut groove or the like on the outer peripheral portion of the shaft cylinder 1 and capable of elastic displacement is provided at a required position, and the pressing portion 1
Sliding tube 2 which has a projection 1d formed on the inner surface of c and is in contact with the projection 1d
A groove portion 22b is formed on the outer peripheral portion of No. 2, and the protrusion 1d is engaged with the groove portion 22b by the finger pressure of the pressing portion 1c to prevent the sliding tube 22 from moving in the axial direction.

[0014]

As a result of the above, the feeding body 16 is fixed to the outside of the touch finger portion 2.
It is possible to slide backward by pulling 0 lightly with a finger and bringing the locking piece 19 along the guide slit 15. Then, when the finger is released, the holding chuck 18 holds the lead and returns to the front, so that the lead can be fed out. This amount of extension is the value of the interval A at which the rear end of the touching finger portion 20 abuts the flange portion 13b of the base 13 that faces the touching portion 20.

When the lead is normally fed out, the rear end of the knock cover may be knocked, and the lead guide 10 at the tip of the lead case 9 connected to the knock cover is provided with the collar portion 9b and the sliding tube 2.
2 and the rear end portion 22c of the coil spring 12, which is interposed between the chuck case 2 and the chuck case 2 while compressing the coil spring 12.
Forward, and as shown in FIG.
(The core guide 10 and the chuck case 2 are interlocked with each other because they abut on the projecting portion 8b which constitutes the above).

When the lead projects from the tip pipe 14, the lead advances at intervals where the tip of the tightening cylinder 6 abuts the step 16a of the feeding body 16. In this state, the chuck case 2 is prevented from advancing, so that the protrusion 11 is elastically protruded.
The lead-fixing chuck 3 is released by contacting the tip of the lead guide 10 with the rear end of the lead-fixing chuck 3 while moving forward. (When the lead is not inserted through the lead fixing chuck 3, the lead falls at this time and comes into contact with the holding chuck 18 or comes into contact with the rear end of the previous lead.) Next, when the rear end knock of the knock cover is released, Since the rear end of the protrusion 11 abuts on the protrusion 8b, the chuck case 2 moves backward together with the lead case 9 while the fixed chuck 3 remains open while the lead is fixed to the holding chuck 18, and the chuck case 2 slides. When the rear end of the projection 22a of the moving tube 22 is prevented from moving backward, only the core case 9, that is, the core guide 10 is retracted, and the projection 11 passes over the projection 8b again and is positioned between the projection 8a and the projection 8a. . By repeating the above, the lead is sequentially fed out. (The core is holding chuck 18
The core moves forward by repeating the above knocking operation even when the core is in contact with or is in contact with the rear end of the front core.)

When the core is projected from the tip pipe 14 longer than necessary, the touching finger portion 20 is pulled backward (interval A), and the mouthpiece 13 is further spaced from the barrel 1 as shown in the drawing. When retracted at B, the stepped portion 16a of the feeding body 16 comes into contact with the tip of the tightening cylinder 6, the chuck case 2 and the lead fixing chuck 3 move backward, and the rear end of the lead fixing chuck 3 moves toward the lead guide 10. The lead is brought into contact with the tip, and the lead fixing chuck 3 is pressed and moved to release the lead gripping state. That is, the interval B shown in the figure is set to be larger than the interval C shown in the figure so that the lead gripping of the lead fixing chuck 3 can be released. If this state is maintained and the tip of the lead is pressed (the tip of the lead is pressed against the paper surface or the like), the lead is sunk into the tip pipe 14.

When the touch finger 20 is released from the above state,
Although the mouthpiece 13 returns to the original position, since the touching finger portion 20 further advances by the distance A, the tip pipe 1 has a length corresponding to the distance A.
The core protrudes from 4. That is, the protrusion length of the core is set to a substantially constant size by the above operation. By the way, although the spring 12 for urging the pair of sliding tubes 22 is set to be strong enough to the spring 21 for urging the touching finger portion 20, the sliding tube 22 is retracted in order to set the protruding length of the core. To do so, it needs to be not too strong. However, in this case, it must be made to withstand the writing pressure. Therefore, during writing, finger pressure is applied to the pinching portion 1c of the barrel 1 to withstand writing pressure.

[0019]

As described above, the present invention eliminates structural defects such as poor sliding of touching finger portions and loosening of screwed portions because there is no notched slit up to the tip of a conventional shaft coupling. It
Further, the shaft cylinder, the mouthpiece, the feeding body, the touching finger portion, the sliding tube, and the core case are each formed as a synthetic resin molded product to simplify the members, so that a significant cost reduction can be realized. or,
Although there is a problem of quality in the conventional complicated metal working and screwed portion 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, when the core is projected longer than necessary from the tip pipe, the protrusion length of the core can be adjusted properly only by retracting the touching finger, so re-grip the barrel as in the conventional example. It eliminates the hassle of knocking the end and the trouble of re-extending the lead, and it is possible to provide a very easy-to-use touch-fing type mechanical pencil. Also, if the tip of the tip pipe is pressed against the paper surface while the rear end is knocked, the tip of the core can be retracted into the tip pipe as in the conventional case.

[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, a part of which is half-sectioned.

FIG. 2 is a partially non-cross-sectional view showing an engaging portion between a core guide and a chuck case of the embodiment.

FIG. 3 is a diagram showing a fastening portion between a core case and a shaft tube of the embodiment.

[Explanation of symbols]

 1 Shaft cylinder 1a Step part 1b Window part 1c Clamping part 1d Projection part 2 Chuck case 2a Groove part 2b Collar part 3 Core fixing chuck 4 Ball 4'ball 5 Coil spring 6 Tightening cylinder 7 Slit part 8 Locking part 8a Projection part 8b Projection 9 Core case 9a Collar 9b Collar 10 Core guide 11 Projection 12 Coil spring 13 Base 13a Shaft 13b Collar 14 Tip pipe 15 Guide slit 16 Feeding body 16a Step portion 17 Center of feeding body 18 Holding chuck 19 Locking piece 19a Locking groove 20 Touching finger portion 20a Projection 21 Coil spring 22 Sliding tube 22a Projection 22b Groove 22c Rear end 22d Locking projection 23 Slit 23a Slit 23b Small slit 23c Slit 24 Taper 25 step portion 26 rib-like bulging portion 26a protrusion

Claims (3)

[Claims] 1. A structure in which the core fixing chuck 3 has a ball-tightening structure to have a sufficient core holding force for writing, but a slight force is required to pull out the core from the core fixing chuck 3. In the pencil, the shaft cylinder 1, the base 13, the feeding body 16, the touch finger portion 20, the sliding tube 2
2. The main members of the core case 9 are each formed as a synthetic resin molded product, and the guide slit 15 is formed slightly in front of the center of the shaft side surface.
Is attached to the tip of the sliding pipe 22, and further, the sliding pipe 22 is attached to the shaft cylinder 1 so as to move the shaft in an appropriate range, and is fitted into the guide slit 15 inside the base 13. 16 which has a locking piece 19 which is slidable
And holding chuck 18 at the center of the feeding body 16.
Is provided and is engaged with the locking piece 19 to extend the feeding body 16
A ring-shaped touch finger portion 20 that is integrally interlocked with the touch finger portion 20 is provided outside the base 13, and inside the touch finger portion 20, the touch finger portion 20 is provided.
A coil spring 21 is interposed between the base 13 and the base 13 to press the touching finger portion 20 forward, and a locking portion 8 is provided at the rear of the chuck case 2 for tightening the lead fixing chuck 3 with a ball. A core case 9 is provided so as to be interlocked with each other in an appropriately frictionally engaged state. Further, the core case 9 is prevented from retreating with respect to the shaft cylinder 1, and the rear end of the sliding pipe 22 and the core case 9 are provided. A coil spring 12 is urged in between, so that the core fixing chuck 3, the chuck case 2, and the mouthpiece 13 are integrated with the sliding tube 22 with respect to the shaft cylinder 1 so as to retreat forward relative to the shaft cylinder 1 within an appropriate range. A touch-fed mechanical pencil that is characterized in that 2. The amount of retreat of the sliding tube 22 relative to the barrel 1
2. The finger-feeding type mechanical pencil as set forth in claim 1, wherein the lead fixing chuck 3 is set to have a length (amount) in which the rear end of the lead fixing chuck 3 is pressed and moved by the tip of the lead case 9 to release the grip of the lead. 3. A pinching portion 1c for engaging the outer peripheral portion of the sliding tube 22 with finger pressure to prevent axial movement of the sliding tube 22 is provided on the outer peripheral portion of the barrel 1 by finger pressure. The touch-fed mechanical pencil described in 1.