JP2002362090A - Mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical pencil extremely shortening a residual lead impossible to write and eliminating a waste. SOLUTION: The mechanical pencil comprises a lead guide cylinder 9 provided to lock a front end to a barrel provided at a rear side of an axial center of a slider 10, and a spring laid between a front face of a collar part provided at the rear end of the guide cylinder and a stepped part provided at a front of an inner hole of an opening tip 3. Thus, the rear end of the guide cylinder is contacted with the front end of the chuck 8 in a state in which the slider and the lead guide cylinder are urged to a rear to the opening tip. Advancing of the slider is prevented to the opening tip in a state in which the chuck is suitably advanced in the previous state. The chuck is further advanced, a clamper is contacted with the rear end of one side. The chuck is furthermore advanced, the lead grasping state of the chuck is released, and the chuck is retracted from that state. Thus, before the chuck is engaged with the clamper to start lead grasping, the front end of the guide cylinder is locked to the rear of the slider again, and the guide cylinder and the slider are cooperated together with the chuck to become retractable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a mechanical pencil with a minimum residual core.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional mechanical pencil. As shown in FIG.
A chuck 20 is mounted on the outer periphery of the gripping portion with a fastener 21 fitted thereto through the chuck 8, and is chucked by a chuck spring 23 urged between the core case 19 and the barrel 16 fixed to the rear end of the chuck 20. 20 is clamped with the fastener 21 to grip the supply core 15. A slider 22 is fixed to the tip of the lip portion 17 attached to the tip of the shaft cylinder 16, and the slider 22 is formed of a tip pipe 22b in front of the core guide shaft portion 22a and a rear portion made of an elastic material such as rubber. The holding chuck 22c is fixed, and the residual core 14 penetrates the holding chuck 22c and protrudes from the tip pipe 22b. In this state, when the chuck 20 is knocked and moved forward, the supply core 15 is moved forward while being gripped because the chuck 20 is fastened by the fastener 21. When the fastener further advances, the fastener 21 comes into contact with the step 17a of the lip 17 and only the chuck advances, so that the gripping of the lead is released, and the front end of the lead contacts the rear end of the remaining lead 14. If you release the knock from that state, the chuck retracts with the lead stopped,
The gripping is completed in a state where the gripping portion of the chuck is frictionally engaged with the core from the time when the gripping portion starts to engage with the fastener 21 and the core is slightly retracted. That is, when the rear end of the remnant core 14 comes off the gripping portion of the chuck 20, the leading end of the supply core 15 contacts the rear end of the remnant core 14 in the next knock, but the front end of the supply core 15 contacts the holding chuck 22c. Since the chuck is not engaged, the chuck is fastened by the fastener 21 when the chuck 20 is retracted, and the lead is engaged with the chuck slightly before the chuck to slightly retract the lead. A gap 24 is generated between them. Therefore, when writing pressure is applied to the front end of the remnant core 14, the retraction of the core by the gap occurs. When you raise that state, the brush feeling is bad,
For a while, every time you knock, you will go back and forth. Therefore, in many cases, knocking is repeated and the remaining core is discharged. In this case, there is a problem that the length between the substantially front end of the chuck holding portion and the front end of the front end pipe is wasted as a residual core. The length varies depending on the design, but is usually 7m.
m to about 12 mm. In addition, even when used with patience, when the rear end of the residual core advances to a position outside the holding chuck, the core falls off the front end of the distal end pipe.

A tip is provided at the front end of the barrel, and a core case and a rear chuck having a front end of the core case fitted with a fastener on the outer periphery of a gripping portion are movable back and forth by a spring. A front chuck is provided so as to interlock with a front of the rear chuck via a joint,
There has been known a mechanical pencil called a top chuck or a double chuck in which a grip portion of the front chuck is engaged with a front end hole of a mouth portion to grip a core. In this case, the front chuck can hold a residual core having a length of about 1 mm, and there is no waste of the core. However, there is a problem that it is difficult to provide a low-priced mechanical pencil due to its complicated structure. In addition, since the tip is formed as a chuck, there is a problem that is difficult when a wire is drawn against a ruler.

[0004]

SUMMARY OF THE INVENTION The present invention makes it possible to provide a mechanical pencil that is extremely easy to use and low in unit price while reducing waste by extremely reducing the amount of residual core.

[0005]

The present invention has the following arrangement to achieve the above object. The mechanical pencil according to claim 1 is provided at the front end of the mechanical cylinder in a mechanical pencil configured to grip the core by the forward and backward movement of a chuck disposed in front of the barrel and to extend the core. A holding chuck is provided at the approximate front end of the slider's inner hole where the tip is inserted into the inner hole of the lip with the tip protruding from the front end of the lip, and the rear end is fastened to the rear of the slider's outer peripheral part. A piece that extends in contact with the front end of the tool is provided at an appropriate interval, and a core guide cylinder is provided by locking the front end to a cylinder provided behind the axis of the slider. A spring was laid between the front face of the flange provided at the rear end and the step provided in front of the inner hole of the lip, and the slider and the core guide cylinder were urged rearward with respect to the lip. In this state, the rear end of the core guide tube is In this state, the slider is prevented from moving forward with respect to the lip portion in a state in which the chuck has advanced appropriately, the chuck further advances, the fastener comes into contact with the rear end of the one-piece portion, and further advances, and the chuck further advances. Is released, the chuck is retracted from that state, and before the chuck engages with the fastener to start the core gripping, the front end of the core guide cylinder is locked again behind the slider. In addition, the core guide cylinder and the slider together with the chuck are configured to move backward in conjunction with each other.

[0006]

Embodiments will be described with reference to the drawings.
FIG. 1 shows a knock type mechanical pencil according to an embodiment of the present invention, in which a chuck 8 is inserted into a shaft hole of a shaft coupling 11 from a rear end side after a fastener 12 is fitted around an outer periphery of a leading end grip portion thereof. The shaft joint 11 is inserted into the shaft hole of the shaft cylinder 1, and the locking portion 8 b at the rear end of the chuck 8 is locked in a connection hole provided in the shaft portion 4 a at the front end of the core case 4. Further, a chuck spring 13 is laid between the step portion 4b provided in front of the lead case 4 and the rear end of the shaft joint 11 so as to pull the chuck 8 backward. Further, the front portion of the chuck 8 is constituted by a halves or a halves which can be expanded and contracted.

The slider 10 has a holding chuck 10b made of rubber or the like which is inserted through a core into a substantially front end of an inner hole portion of a tip pipe 10a and is appropriately frictionally engaged. A step 10c is provided behind the tip pipe 10a and a rear end is provided. Part 10g is fastener 12
A part 10f is extended at a required portion of the rear end of the front end pipe 10a so as to be in contact with the front end of the front pipe at an appropriate interval, and
A slit portion 10d is provided in a cylindrical portion provided behind the axis portion of the slider 10. The slider 10
Not only in one piece but also the tip pipe 10a and the flange 10
c The rear cylindrical portion may be provided separately. If the slider is made of a resin molded product, the holding chuck can be formed of an integral elastic piece.

The core guide cylinder 9 has a flange 9a at a substantially rear end thereof, and a projection 9b at an outer peripheral surface of a substantially front end of the cylinder in front thereof.

As described above, the slider 10 is inserted into the inner hole of the lip portion 3 so that the distal end protrudes from the front end of the lip portion, and the piece 10f is formed in the guide groove formed on the peripheral surface of the inner hole of the lip portion. 3a, a projection 9b provided on the outer peripheral surface of the front guide end of the core guide tube 9 projects through the slit 10d of the slider 10, and the projection 9b is locked on the rear end surface of the slit 10d. In addition, a spring 10e is laid between the front surface of a flange 9a provided at the rear end of the core guide cylinder 9 and a step 3b provided in front of an inner hole of the lip portion 3, and a slider 10 and a core guide are provided. When the cylinder 9 is urged rearward with respect to the lip portion 3, the rear end of the core guide cylinder 9 is
Is provided in contact with the front end of Further, with the chuck 8 advanced as appropriate, the slider 10 is attached to the tip step 3d of the tip 3.
Abuts the flange portion 10c, thereby preventing the slider from moving forward with respect to the lip portion. Also, a step 3e of the lip 3 provided separately.
The step 10h of the slider 10 may be brought into contact with and regulated. The rear end surface of the slit portion 10d of the slider 10 has a step and a tapered opening is provided at the rear end, and the protrusion 9b of the core guide tube 9 elastically expands the opening. It can be provided so as to be engaged with the step. Further, when the slider 10 is formed as an integral resin molded product, the slit portions 10d and the piece portions 10f are provided at different circumferential positions so as not to hinder mold release during molding.

A tip 3 is attached to the shaft 1a at the front end of the barrel 1 by means such as screwing, and a flange 11a provided at the front end of the shaft joint 11 is connected to the front end of the shaft 1a of the barrel. Shaft coupling 1 sandwiched between the inner step of the lip 3
1 is fixed to the barrel 1. After the core guide cylinder 9 and the slider 10 are fitted into the inner hole of the lip portion 3, a locking portion (formation of a projection, locking (Attachment of a member).
At this time, it is necessary that the rear end of the core guide tube 9 be in contact with the front end of the chuck 8 in the core gripping state.

Further, from the state shown in FIG. 1, the step 10c of the slider 10 abuts on the step 3d at the tip end of the lip portion 3 with the chuck 8 appropriately advanced, so that the slider 10 advances with respect to the lip portion 3. When the chuck 8 is further advanced, the fastener 12 comes into contact with the rear end 10g of the slider piece 10f, and further advanced to release the chucked state of the chuck 8, the core is extended.

When the chuck 8 is in the most advanced state, the protrusion 9b at the front end of the core guide cylinder 9 is inserted into the slit 10 of the slider.
The chuck 8 is retracted from its most advanced state by contacting the front end face of the front end face d, and before the chuck 8 engages with the fastener 12 to start the core gripping, the slit portion of the slider is again turned on. The projection 9b at the front end of the core guide cylinder 9 is locked to the rear end face of 10d, and the core guide cylinder 9 and the slider 10 move backward together with the chuck 8 in conjunction with each other.

[0013]

The knock cover 5 is moved from the state shown in FIGS.
By repeating the knocking and its release, the chuck 8 moves back and forth in conjunction with the lead case 4 like a normal mechanical pencil, and the lead is fed out from the front end of the tip pipe 10a. That is, the step 10c of the slider 10 abuts on the step 3d at the tip end of the lip portion 3 with the chuck 8 appropriately advanced, and the slider 10 is prevented from moving forward with respect to the lip portion 3. In the meantime, the chuck 8, the fastener 12, and the rear end 10g of the slider piece 10f are integrally linked. The chuck 8 is further advanced, and the fastener 12 is moved to the slider piece 10.
f is brought into contact with the rear end portion 10g and further advanced to release the chucked state of the chuck 8 so that the lead is fed out. Accordingly, the lead-out amount is substantially the same as the interval at which the chuck 8 advances and the front end of the fastener 12 abuts on the rear end 10g of the slider piece 10f.

When the lead is consumed together with writing, the trailing end of the lead comes off the lead gripping portion of the chuck 8 and becomes a residual lead. The next lead is sent from the lead case 4 to the chuck 8 as a supply lead.
FIG. 4 shows a state in which the residual core 14 is located in the slider 10 and the supply core 15 held by the chuck 8 is located behind the residual core 14. In this state, the chuck 8 moves forward as appropriate, and the step 10c of the slider 10 comes into contact with the step 3d at the tip end of the lip portion 3. Further, the chuck 8 moves forward and the fastener 12 moves to the rear end 10g of the slider piece 10f. , And the chuck 8 is advanced and the lead is fed out until the lead grip is released.

As shown in FIG. 3, when the chuck 8 is in the most advanced state, the front end of the supply core 15 is in contact with the rear end of the residual core 14. Also, when the chuck 8 is retracted from the most advanced state, before the chuck 8 engages with the fastener 12 and starts to grip the core, the front end of the core guide cylinder 9 is again formed on the rear end face of the slit portion 10d of the slider. The portion 9b is locked, and the core guide cylinder 9 and the slider
Retreats in conjunction. That is, when the lead guide tube 9 and the slider 10 start retreating in conjunction with the chuck 8, the lead gripping part of the chuck 8 is in a state where the lead is opened, and the leading end of the supply lead 15 is attached to the rear end of the remaining lead 14. Maintain the contact state. When the chuck 8 further retreats, the chuck 8 retreats while holding the core with respect to the fastener 12. Therefore, before the chuck 8 starts gripping the lead with the fastener 12, the lead guide cylinder 9 and the slider 10 move together with the chuck 8 to retreat, and the lead of the lead 14 is released until the trailing end of the residual lead 14 comes off the holding chuck 10b. Even if pressure is applied to the front end, there is no dive and the writing feel is good. In addition, by providing the holding chuck at the front end of the inner hole of the front end pipe as much as possible, the length of the unwritable residual core can be shortened.

The interval at which the chuck 8 advances as appropriate and the step 10c of the slider 10 abuts on the step 3d of the tip end of the lip 3 ends when the chuck 8 starts gripping the core with respect to the fastener 12. Specified in consideration of the amount of retreat up to.
Also, due to variations in the core gripping portion 8a of the chuck and the core diameter,
The protrusion of the front end of the chuck 8 with respect to the front end of the fastener 12 in the state where the core is gripped fluctuates, but until the step 10c of the slider 10 comes into contact with the step 3d of the tip of the lip 3, the chuck 8 and the fastener 12, one part of slider 10f
The rear end 10g moves forward integrally, so that the fastener 1
The distance between the front end of the slider 2 and the rear end 10g of the slider piece 10f is kept constant, and there is no influence on the variation in the amount of lead feeding. However, the distance between the front end of the fastener 12 and the rear end 10g of the slider fluctuates due to dimensional variations of predetermined portions such as the lip 3, the slider 10, and the core guide tube 9, so that the influence is present.

[0017]

The construction and operation of the present invention are as described above, and the remaining core, which is not writable, is extremely short, and the core is not wasted. In addition, since a small amount of residual core is discharged with a small knock, the trouble can be extremely reduced, and the convenience of use and the simple structure make it possible to provide a low-priced mechanical pencil.

[Brief description of the drawings]

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

FIG. 2 is an enlarged half sectional view showing a main part of the mechanical pencil of the present invention, showing a state in which a chuck is retracted.

FIG. 3 is an enlarged half sectional view showing a main part of the mechanical pencil of the present invention, showing a state in which the chuck is most advanced.

FIG. 4 is an enlarged half cross-sectional view showing a main part of the mechanical pencil of the present invention, showing a state in which the chuck is retracted and the core starts to be gripped by the fastener.

FIG. 5 is a half sectional view showing an enlarged main part of a conventional mechanical pencil.

[Explanation of symbols]

 Reference Signs List 1 shaft cylinder 1a shaft 2 grip 3 mouth 3a guide groove 3b step 3c shaft 3d tip step 3e step 4 core case 4a shaft 4b step 5 knock cover 6 clip 7 eraser 8 chuck 8a core grip 8b Locking part 9 Core guide cylinder 9a Flange part 9b Protrusion part 10 Slider 10a Tip pipe 10b Holding chuck 10c Step part 10d Slit part 10e Spring 10f One part 10g Rear end part 10h Step part 11 Shaft joint 11a Flange part 12 Fastener 13 Chuck Spring 14 Remaining core 15 Supply core 16 Shaft barrel 17 Tip 17a Step 18 Shaft joint 19 Core case 20 Chuck 20a Locking part 21 Fastener 22 Slider 22a Core guide shaft part 22b Tip pipe 22c Holding chuck 23 Chuck spring 24 Gap

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Seiichi Kobayashi 2-5-12 Irie, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Pencil Co., Ltd. Yokohama Office F-term (reference) 2C353 FA04 FC02 FC03 FC13 FE02 FE03 FE04 FE05 FE14 FE16 FG06

Claims (1)

[Claims] In a mechanical pencil configured to grip a lead by a back and forth movement of a chuck disposed in front of a barrel and to draw out the lead, a tip provided at a front end of the barrel is provided. A holding chuck is provided at a substantially front end of the inner hole of the slider which is inserted in a state in which the front end of the hole is projected from the front end of the lip portion. At the same time, a piece that is in contact with the pole extends with a gap, and a lead guide tube is provided by locking the front end to a tube part provided behind the axis of the slider, and it is provided at the rear end of the lead guide tube. A spring is laid between the front surface of the provided flange portion and a step portion provided in front of the inner hole portion of the mouth portion, and the slider and the core guide tube are urged rearward with respect to the mouth portion while the core guide tube is urged. The rear end is provided in contact with the front end of the chuck. The slider is prevented from advancing with respect to the lip portion while the chuck is appropriately advanced, the chuck further advances and the fastener comes into contact with the rear end of the piece, and the chuck further advances to grip the core of the chuck. Is released, the chuck is retracted from that state, and before the chuck engages with the fastener to start gripping the core, the front end of the core guide cylinder is locked again behind the slider, and the chuck is moved together with the chuck. A mechanical pencil characterized in that the lead guide tube and the slider are configured to move back together.