JP2003001991A - Mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost mechanical pencil having good handleability by extremely shortening a residual lead becoming impossible to write and eliminating a waste. SOLUTION: The mechanical pencil comprises a chuck arranged at a front side of a barrel to grasp the lead by its longitudinal movement and to feed the lead. The pencil further comprises a slider inserted at its distal end into an inner hole of a mouth end provided at a front end of the barrel in a state in which the distal end is projected from a front end of the mouth end, a holding chuck provided at a substantially front end of an inner hole of the slider, an outer cylinder provided at a rear part of the slider so that a rear end is opposed at a suitable interval to a front end of a clamping unit. In this case, the slider is locked so as to advance or retract at a predetermined interval with respect to the mouth end and the slider is disposed at a retracted position so that an interval between the rear end of the outer cylinder and the front end of the clamping unit becomes a substantially lead feeding amount.

Description

Description: 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. 2. Description of the Related Art FIG. 5 shows a conventional mechanical pencil. As shown in FIG.
A chuck 20 is installed by fitting a fastener 21 on the outer periphery of the gripping portion through the chuck 8, and the chuck 20 is chucked by a chuck spring 23 urged between the core case 19 fixed to the rear end of the chuck 20 and the barrel 16. 20 is clamped with the fastener 21 to grip the supply core 14. A slider 22 is fixed to the tip of the lip portion 17 attached to the tip of the barrel 16. The slider 22 has a tip pipe 22 b in front of the core guide shaft portion 22 a and a rear portion made of an elastic material such as rubber. The holding chuck 22c is fixed, and the residual core 13 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 14 moves 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 mouth portion 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 13. If you release the knock from that state, the chuck retracts with the lead stopped,
The grip is completed in a state in which the gripping portion of the chuck is frictionally engaged with the wick from the time when the grip starts to engage with the fastener 21 and the wick is slightly retracted. That is, when the rear end of the remnant core 13 comes off the gripping portion of the chuck 20, the leading end of the supply core 14 abuts the rear end of the remnant core 13 in the next knock, but the front end of the supply core 14 contacts the holding chuck 22c. Since the chuck is not engaged, the chuck is fastened with the fastener 21 when the chuck 20 is retracted, and the lead is engaged with the chuck slightly before the chuck, and the lead is slightly retracted. A gap 24 is generated between them. Therefore, when writing pressure is applied to the front end of the remnant core 13, the retraction of the remnant core 13 occurs. When you raise that condition, the brush feel is bad,
For a while, it repeatedly goes under the core every time it knocks. 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 distal 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, in which a fastener is fitted on the outer periphery of a gripping portion at the front end of the core case, can be moved 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. SUMMARY OF THE INVENTION The present invention makes it possible to provide a mechanical pencil which is extremely easy to use and low in unit price while reducing waste by extremely reducing the residual core amount. [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 which the mechanical pencil is gripped by the forward and backward movements of a chuck disposed in front of the cylindrical cylinder and is extended. A holding chuck is provided at the approximate front end of the slider inner hole where the tip is inserted into the inner hole of the lip part with the tip protruding from the front end of the lip, and the rear end of the slider has a fastener at the rear of the slider. An outer cylinder portion is provided so as to face the front end at an appropriate interval, and the slider is locked so as to advance and retreat at a predetermined interval with respect to the lip portion, and at the position where the slider retreats, the outer cylinder portion is provided. The distance between the rear end of the fastener and the front end of the fastener is substantially the amount of extension of the core. An embodiment 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 10 from a rear end side thereof after a fastener 11 is fitted around the outer periphery of a leading end gripping portion. The shaft joint 10 is inserted into the shaft hole of the barrel 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 12 is laid between the step portion 4b provided in front of the lead case 4 and the rear end of the shaft coupling 10 so as to pull the chuck 8 backward. Further, the front portion of the chuck 8 is constituted by a halves or a halves that can be expanded and contracted. The slider 9 has a holding chuck 9b made of rubber or the like which is inserted through a core into a substantially front end of an inner hole portion of the tip pipe 9a and is appropriately frictionally engaged. An outer cylindrical portion is provided behind the tip pipe 9a via a step 9d. 9c is provided integrally, and the rear end 9f is opposed to the front end of the fastener 11 at an appropriate interval. A groove 9e is formed on the outer periphery of the outer cylindrical portion 9c, and a protrusion 3d is formed at a required position on the end surface of the rib 3a provided on the inner surface of the mouth portion 3, and the protrusion 3d is formed on the outer cylindrical portion 9c.
The slider 9 is engaged with the lip portion 3 so as to advance and retreat at predetermined intervals. Further, the outer cylinder may be a single piece divided into a plurality of parts, or the locking relationship between the groove provided on the outer cylinder and the mouth and the projection may be reversed, and the locking shape is limited. Not done. Also slider 9
The end pipe 9a and the outer cylinder 9c can be provided separately as well as integrally. If the slider is made of a resin molded product, the holding chuck can be formed of an integral elastic piece. As described above, the slider 9 is inserted into the inner hole of the lip portion 3 in a state where the tip portion projects from the front end of the lip portion,
The protrusion 3d provided in the mouth portion is formed into a groove 9e of the outer cylindrical portion 9c.
The slider 9 advances and retreats at a predetermined interval with respect to the lip portion 3. 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 10a provided at the front end of the shaft coupling 10 is connected to the front end of the shaft 1a of the barrel. The shaft joint 1 is sandwiched between the lip 3 and the inner step.
0 is fixed to the barrel 1. From the state shown in FIG. 2, the step 9d of the slider 9 comes into contact with the step 3b of the tip 3 while the chuck 8 is appropriately advanced, so that the slider 9 advances with respect to the tip 3. When the chuck 8 is further advanced, the fastener 11 comes into contact with the rear end 9f of the outer cylindrical portion 9c of the slider, and further advanced to release the chucked state of the chuck 8, so that the core is extended. (See FIG. 3) Note that the interval 15a shown in FIG. 2 is substantially the amount of extension of the core. The distance 15b between the step 3b of the tip 3 and the step 9d of the slider 9 has a relationship of 15c-15a shown in FIG. The gap 15b is formed at the front end of the protrusion 3d of the rib 3a provided on the inner surface of the lip portion 3 by the groove 9 of the outer cylinder 9c.
It is set in a state where the front end of e is in contact. When the cores are sequentially fed out and the rear end of the core is separated from the front end of the chuck, that is, the rear end of the residual core 13 is located in front of the chuck, and the front end of the supply core 14 is positioned after the residual core. When the chuck 8 is engaged with the fasteners 11 to start gripping the wick, the chuck 8 is retracted from the advanced state in a state where the wick is engaged with the chuck. At the same time, the chuck is retracted, and the chucking of the chuck core is completed. Therefore, as shown in FIG. 4, a gap 25 is formed between the rear end of the remnant core 13 and the supply core 14.
Since the rear end of 3 is in contact with the front end of the supply core 14, the core does not dive. That is, this is achieved by making the size of the lead retracted with the chuck substantially equal to the gap 15b. 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 9a. That is, when the chuck 8 is appropriately advanced, the tip 3
The step 9d of the slider 9 abuts on the tip step 3b of
The forward movement of the slider 9 with respect to the lip portion 3 is prevented, the chuck 8 further advances, and the fastener 11 contacts the rear end 9f of the outer cylindrical portion 9c of the slider, and further advances to move the chuck 8
The lead is fed out by releasing the lead gripping state. The lead-out amount is substantially equal to the interval 15a at which the front end of the fastener 11 contacts the rear end 9f of the outer cylindrical portion 9c of the slider. When the lead is consumed together with the writing, the trailing end of the lead comes out of the lead holding portion of the chuck 8 and becomes the residual lead 13.
The next lead is sent from the lead case 4 to the chuck 8 as a supply lead 14. FIG. 4 shows a state in which the residual core 13 is located in the slider 9 and the supply core 14 held by the chuck 8 is located behind the residual core 13. In this state, when the chuck 8 is advanced to release the core holding, the front end of the supply core 14
3 comes into contact with the rear end, but when the chuck 8 is retracted from the advanced state and the chuck 8 engages with the fastener 11 to start gripping the lead, the lead is engaged with the chuck. As shown in the drawing, a gap 25 is formed between the rear end of the remnant core 13 and the supply core 14 in order to complete the gripping of the chuck core by retreating together with the chuck. However, by making the size of the retraction of the lead along with the chuck substantially equal to the gap 15b, the slider 9 is retreated by applying the pen pressure to the tip of the remnant 13 and the rear end of the remnant 13 Abuts against the front end of the supply core 14 so that no core dive occurs. Therefore, until the rear end of the residual core 14 is disengaged from the holding chuck 10b, even if pressure is applied to the front end of the core, there is no dive in the core 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 reduced. The interval 15b at which the step 9d of the slider 9 comes into contact with the tip step 3b of the tip 3 while the chuck 8 is appropriately advanced, and the forward movement of the slider 9 with respect to the tip 3 is set as follows. , The chuck 8 is defined to be substantially the same as the retreat amount from when the chuck 8 starts to hold the core to the end of the fastener 11 and ends. Also, due to variations between members,
There is an error in the identity of the retraction amount between the start and end of the chuck 8 by the chuck 8 with respect to the fastener 5b and the fastener 11, and the error increases the dispersion of the lead-out amount, or the residual core 13 When the slider 9 retreats by applying the pen pressure to the tip of the supply core, a state where a small gap remains between the rear end of the residual core 13 and the front end of the supply core 14 occurs, but there is no problem in actual use. . As shown in FIG. 4, when the core is extended in the state of the residual core, the front end of the fastener 11 is connected to the rear end 9f of the outer cylindrical portion 9c.
Abut on the space 15c. That is, the interval 15c =
Since the interval is 15a + 15b, the front end of the supply core 14 comes into contact with the rear end of the residual core 13 and the front end of the supply core 14 pushes the rear end of the residual core 13 at substantially the interval 15a. Therefore, in the case of a mechanism such as a normal mechanical pencil, the feed amount of the lead in the residual core state (however, when the front end of the supply lead is not engaged with the holding chuck) is reduced, and the residual core is discharged. Inconveniences such as an increase in the number of knocking operations (forward and backward movements of the chuck) are eliminated. The construction and operation of the present invention are as described above, and the unwritable residual core is extremely short, and the core is not wasted, so that it is economical. Further, since a small amount of remnant is discharged, it can be carried out with a small amount of knocking, the trouble can be extremely reduced, and the convenience of use and the simple structure make it possible to provide a low cost unit mechanical pencil.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a longitudinal half sectional view of a mechanical pencil which is 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 the 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 has been most advanced. FIG. 4 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 in a residual core state. FIG. 5 is a half sectional view showing an enlarged main part of a conventional mechanical pencil. [Description of Signs] 1 Shaft 1a Shaft 2 Grip 3 Tip 3a Rib 3b Tip 3c Shaft 3d Projection 4 Core case 4a Shaft 4b Step 5 Knock cover 6 Clip 7 Eraser 8 Chuck 8a Core grip 8b Locking part 9 Slider 9a Tip pipe 9b Holding chuck 9c Outer cylinder part 9d Step part 9e Groove part 9f Rear end 10 Shaft joint 10a Flange part 11 Fastener 12 Chuck spring 13 Remaining core 14 Supply core 15a Interval 15b Interval 15c Interval 16 axis Cylinder 17 Tip 17a Step 18 Shaft joint 19 Core case 20 Chuck 20a Locking part 21 Fastener 22 Slider 22a Core guide shaft 22b Tip pipe 22c Holding chuck 23 Chuck spring 24 Gap 25 Gap

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Seiichi Kobayashi             2-5-12 Irie 2-chome, Kanagawa-ku, Yokohama-shi, Kanagawa             No. Mitsubishi Pencil Co., Ltd. Yokohama Office F-term (reference) 2C353 FA04 FC13 FE04 FE05 FE14                       FE16 FG01 FG06 FG11

Claims (1)

Claims: 1. A mechanical pencil which grips and draws out a lead by a back and forth movement of a chuck disposed in front of the barrel, and is provided at a front end of the barrel. A holding chuck is provided at a substantially front end of an inner hole portion of the slider which is inserted into the inner hole of the lip portion such that a tip portion protrudes from a front end of the lip portion, and a rear end of the slider has a fastener at a rear portion thereof. An outer cylinder portion is provided so as to face the front end of the outer cylinder at an appropriate interval, and the slider is locked so as to advance and retreat at a predetermined interval with respect to the lip portion. A mechanical pencil characterized in that the distance between the rear end of the part and the front end of the fastener is substantially equal to the extension of the core.