JP2003011582A - Mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical pencil, in which a writing touch due to a remaining lead is improved and consequently the remaining lead can be used without going to waste by a method wherein the retreating phenomena due to a gap developing between the remaining lead and the following lead is evaded at writing. SOLUTION: In the mechanical pencil, in which the lead to be delivered by a chuck 21 is made insert in a slider (R) 10 located in a tip mouth 30, the slider 10 has a lead holding part 12a elastically holding an inserting lead, slides forwards by being pushed by a chuck 21, energizes an energizing means 12b and slidingly comes into contact within the tip mouth 30 so as to be so constituted as to slide rearward later than the retreat of the chuck 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical pencil having a chuck mechanism for feeding a lead.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 12, in a mechanical pencil of this type, a slider 110 having a core holding portion 112 fitted in a cylindrical body 111 has a front end portion having a front end portion 1.
It is provided so as to project from 30, and is configured so that the lead fed by the chuck 120 is inserted into the slider 110. According to this conventional mechanical pencil, when the lead is fed out, the chuck 120 moves forward with the lead held therebetween, is opened during the forward movement to release the same lead, and when retracting and returning to the initial state, The concentric core is clamped again by being closed on the way back. Therefore, when the chuck 120 is retracted and closed, the lead is held by the chuck 120 and slightly retracted.

Therefore, in this conventional mechanical pencil, when the residual core 1 is located in front of the chuck 120, the residual core 1 is moved by the succeeding core 2 fed by the chuck 120 when advancing the chuck 120. It will be pushed (see FIG. 12 (a)). And chuck 12
When retracting 0, the trailing core 2 is slightly retracted as described above, so that a gap w1 is formed between the rear end surface of the residual core 1 and the front end surface of the trailing core 2 (see FIG. 12 (b)). Therefore, in the conventional mechanical pencil, the residual core 1 retracts by the gap w1 due to the writing pressure during writing (see FIG. 12C). There is a problem in that the feeling of writing is impaired due to the phenomenon that the remnant core 1 retracts during writing. Therefore, in order to avoid this problem, the residual core 1 is purposefully pulled out and discarded, and the succeeding core 2 is fed out, resulting in wasteful consumption of the residual core 1 and troublesome operation.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to prevent the residual core from retreating due to a gap generated between the residual core and a succeeding core during writing. By avoiding this, it is to provide a mechanical pencil that improves the writing feel due to the residual core and, in turn, can use the residual core without waste.

[0005]

In order to solve the above-mentioned problems, in the first invention, a mechanical pencil in which a lead fed out by a chuck is inserted into a slider (registered trademark) located in a front opening. In the above, the slider has a lead holding portion that elastically holds the inserted lead, slides forward by being pushed by the chuck, and is biased by the biasing means and slidably contacts the inside of the front opening. ,
It is characterized in that it is configured to slide rearward after the chuck is retracted.

Here, the slider is, for example, integrally provided with a core holding portion for elastically holding the inserted core inside a cylindrical body slidable in the axial direction.
An urging means is provided outside the tubular body, and the tubular body is slid forward by being pushed by the chuck to be urged by the urging means and the outer peripheral surface of the urging means is in the front opening. The sliding contact causes the chuck to slide rearward after the backward movement of the chuck. The urging means is, for example, an O-ring, a coil spring, or another elastic member, and may be integrally provided on the slider, or may be formed separately from the slider. I don't mind.

According to the above technical means, when the chuck advances, the slider pushed by the advancing chuck slides forward against the bias of the biasing means.
Then, when the chuck moves backward, the slider is slid backward by being biased by the biasing means. At that time, the slider slides backward after the backward movement of the chuck due to the sliding contact resistance with the inside of the front opening. Therefore,
When there is a residual core in the slider, when the chuck advances, the residual core is pushed forward by pressing the rear end surface thereof with the front end surface of the succeeding core. Further, when the chuck retracts, the trailing lead is slightly retracted when it is pinched by the chuck again, so that a gap is temporarily formed between the residual lead and the trailing lead. Next, the slider moves backward after the backward movement of the chuck. At that time, the slider retracts together with the residual core held in the core holding portion,
The rear end surface of the retreated residual core comes into contact with the front end surface of the succeeding core. Therefore, at the time of writing, since there is no gap between the residual core and the succeeding core, the phenomenon that the residual core retreats does not occur.

If the backward movement of the slider is not delayed from the backward movement of the chuck, that is, if the backward movement of the slider and the backward movement of the chuck are started at the same time, the chuck moves backward. At the same time as the start of the operation, the remnant core also retreats, and after the retreat operation of the remnant core is completed, the chuck retreats in order to sandwich the subsequent core again, so that a gap is formed between the residual core and the subsequent core. .

Further, in the second invention, the sliding width of the slider which is biased by the biasing means to slide is:
The size is set to be approximately the same as the retreat width of the lead that retreats slightly when the chuck retracts.

Further, in the third invention, the urging means comprises:
The slider is integrally formed with the slider, and the outer peripheral surface of the slider is slidably contacted with the front opening.

Further, in the fourth invention, the slider is formed by integrally providing an elastic portion made of an elastic material on a tubular body slidable in the axial direction, the elastic portion and the urging means. The core holding portion is integrally provided.

Further, in the fifth invention, since the elastic portion is formed in the tubular body by insert molding, the adhesion strength between the tubular body and the elastic portion is enhanced.

Further, in the sixth invention, the lead holding portion is
A first core holding portion formed on the front end side of the slider,
And a second core holding part formed on the rear side of the second core holding part, wherein the second core holding part is formed so as to come into sliding contact with the core with a frictional force weaker than that of the first core holding part. ing.

According to this technical means, since the frictional force of the second lead holding portion near the chuck is weak, the resistance of the lead fed from the chuck to the writing tip is relatively small. Therefore, it is possible to smoothly guide the lead to the leading end of the writing without supporting the feeding operation of the feeding mechanism by the resistance of the lead being fed.

Further, in the seventh invention, the second core holding portion is formed in a polygonal shape in cross section, and its flat inner surface is slidably contacted with the core.

Further, in the eighth invention, the second core holding portion is provided with a plurality of axially continuous protrusions in the circumferential direction.

Further, in the ninth invention, in order to securely hold the lead against the writing pressure, the lead holding portion has a holding force in the feeding direction of the lead smaller than a holding force in the retracting direction of the lead. Is formed. Here, forming the holding force in the feeding direction of the lead to be smaller than the holding force in the backward direction of the lead means, for example, that the holding force in the feeding direction of the lead is the holding force in the backward direction of the lead. It may be formed in a saw-tooth shape in cross section so as to be smaller than the above.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an example of a mechanical pencil according to the present invention. This mechanical pencil A
Is provided with a feeding mechanism 20 for feeding a lead by a knocking operation or the like on the rear end side of the barrel 40, and a slider 10 for inserting the lead fed by the feeding mechanism 20 and protruding from the front end of the front opening 30. There is.

The feeding mechanism 20 includes a chuck 21 provided at the front end of a lead tank 22, a chuck ring 23 that slides axially around the outer periphery of the chuck 21 to hold the lead in the chuck 21, a lead tank 22 and Chuck 2
1 is provided with a spring 24 for urging the shaft 1 rearward, and the shaft cylinder 4
This is a well-known mechanism configured to move the chuck 21 forward and backward by a knocking operation on the 0 rear end side to feed the lead forward.

According to this feeding mechanism 20, the chuck 2
1 moves forward while sandwiching the lead, and is released from the chuck ring 23 during the forward movement to release the lead while moving forward. Further, when the chuck 21 retreats, the chuck 21 fits into the chuck ring 23 during the retreat and clamps the core again.

Therefore, when the chuck 21 is fitted in the chuck ring 23, the lead is slightly retracted because the chuck 21 closes while retracting.

The slider 10 comprises a tubular body 11 formed in a substantially tapered tubular shape and an elastic portion 12 having a core holding portion 12a and a biasing means 12b (see FIGS. 3 and 4). It is mounted so that it can slide in the axial direction.

The tubular body 11 is made of a metal material such as brass, and a rear edge thereof is integrally formed with a projecting edge portion 11a which prevents the elastic portion 12 from coming off by projecting in the centrifugal direction. There is.

The elastic portion 12 is formed integrally with the tubular body 11 by insert molding, and covers the tubular body 11 from the entire inner peripheral surface to the rear end side outer peripheral surface. The elastic portion 12 forms a lead holding portion 12a inside the tubular body 11 for elastically holding the inserted lead, and a biasing force is applied to the outer periphery of the tubular body 11 on the rear end side. Forming means 12b.

The lead holding portion 12a includes a first lead holding portion 12a1 formed on the front end side of the slider 10 and a second lead holding portion 12a2 formed on the rear side of the first lead holding portion 12a1.
Consists of.

The first core holding portion 12a1 has an annular shape whose inner diameter is slightly smaller than the outer diameter of the core, is formed on the front end side of the slider 10, and has the entire inner peripheral surface as the core. Make sliding contact.

The second core holding portion 12a2 has a polygonal cross-section and is formed in a range from the rear end of the first core holding portion 12a1 to the rear end of the tubular body 11. Then, the second core holding portion 12a2 is brought into sliding contact with the core with a frictional force weaker than that of the first core holding portion 12a1 by partially sliding the flat inner surface thereof onto the core. According to a preferred example of the present embodiment, the second core holding portion 12a2 has a square cross section (see FIG. 5).

Further, the second lead holding portion 12a2 is arranged so that its rear end portion is arranged close to the chuck 21, so that the lead fed from the chuck 21 is immediately held.

The urging means 12b has a large-diameter portion 12b1 having a large diameter so as to increase the sliding contact resistance with the inside of the front opening 30 at the time of restoration after elastic deformation, and the inside of the front opening 30. Small diameter portion 12 formed to have a small diameter so that the sliding contact resistance is relatively small.
and b2. These large diameter portion 12b1 and small diameter portion 12b
The arrangement of 2 is not particularly limited, but in the mechanical pencil A which is a preferable example of the present embodiment, the large diameter portion 12b1 is arranged on the front side and the small diameter portion 12b2 is arranged on the rear side.

In the slider 10 having the above structure, the front end portion of the biasing means 12b is brought into contact with the step portion 31 in the front opening 30, and is biased rearward by the biasing means 12b (FIG. 2). reference).

That is, this slider 10 slides forward while elastically deforming the biasing means 12b by being pushed by the front end surface of the chuck 21 when the chuck 21 moves forward. The elastic deformation amount of the biasing means 12b at this time is larger in the front side portion of the projecting edge portion 11a of the tubular body 11 than in the rear side portion thereof. Then, the slider 10 slides rearward by the restoring force of the elastically deformed biasing means 12b after the chuck 21 retracts, and at that time, the outer peripheral surface of the biasing means 12b slides into the front opening 30. Then, the chuck 21 slides backward after the retreat of the chuck 21.

The timing at which the slider 10 is slid backward is adjusted to be a suitable timing by the ratio of the axial lengths of the large diameter portion 12b1 and the small diameter portion 12b2 of the biasing means 12b. That is, in order to accelerate the timing of sliding the slider 10 backward, the axial length of the large-diameter portion 12b1 is made relatively short and the axial length of the small-diameter portion 12b2 is made relatively long, so that the biasing means is provided. The sliding resistance between the outer peripheral surface of 12b and the inside of the front opening 30 may be reduced. Further, in order to delay the timing of sliding the slider 10 rearward, the axial length of the large diameter portion 12b1 is made relatively large and the axial length of the small diameter portion 12b2 is made relatively short, so that the biasing means is provided. The sliding contact resistance between the outer peripheral surface of 12b and the inside of the front opening 30 may be increased.

The sliding width W when the slider 10 is slid backward is determined by the biasing means 12b which is elastically deformed.
The deformation amount is set so that when the chuck 21 retracts, the dimension is approximately the same as the retracted width of the core that slightly retracts in the chuck 21.

Thus, according to the mechanical pencil A having the above structure, when the slider 1 has the remnant 1, the remnant 1 has a rear end surface when the chuck 21 moves forward. It is brought into contact with the front end surface of the trailing core 2 and is fed forward (state shown in FIG. 2A). Then, when the chuck 21 retracts, the trailing core 2 is clamped again by the retracting chuck 21, and thereby retracts a small amount (width of the dimension W in the drawing) (state shown in FIG. 2B).

The slider 10 is provided with the biasing means 12
It is slid backward by being biased by b. At that time, the slider 10 moves backward slightly behind the retracting operation of the chuck 21 due to the sliding contact resistance between the outer peripheral surfaces of both the large diameter portion 12b1 and the small diameter portion 12b2 of the biasing means 12b and the inside of the front opening 30. Slide (state shown in FIG. 2C).

Therefore, the residual core 1 held by the core holding portion 12a is retracted by the dimension W shown in the figure as the slider 10 slides backward, so that the clearance between the residual core 1 and the succeeding core 2 is increased. Disappears. Therefore, at the time of writing, the phenomenon that the residual core 1 retreats only by the gap between the residual core 1 and the succeeding core 2 does not occur.

Next, another mode of the slider will be described with reference to FIGS. Since the lead holding members 10A, 10B, 10C, 10D and 10E are obtained by partially changing the slider 10 described above,
Portions having the same actions as those of the slider 10 are designated by the same reference numerals, and duplicated detailed description will be omitted.

In the slider 10A shown in FIG. 6, the biasing means 12b has a large diameter portion 12b1 on the rear end side and a small diameter portion 12 on the front end side.
b2, and a concave space portion c is provided on the peripheral wall of the small diameter portion 12b2. According to the slider 10A, the sliding contact resistance between the outer circumference of the small diameter portion 12b2 and the front opening 30 and the elastic force of the biasing means 12b can be adjusted appropriately by the space portion c.

In the slider 10B shown in FIG. 7, the biasing means 12b is composed of a large diameter portion 12b1 on the rear end side and a small diameter portion 12b2 on the front end side, and a convex portion 12b 'is formed on the front end surface of the small diameter portion 12b2. Are provided at predetermined intervals in the circumferential direction, and a recess c is provided on the large diameter portion 12b1 side of the small diameter portion 12b2. According to this slider 10B, the plurality of convex portions 12
b ′ and the space c, the outer circumference of the small diameter portion 12b2 and the front end 3
The sliding contact resistance with 0 and the elastic force of the biasing means 12b can be adjusted appropriately.

Further, the slider 10C shown in FIGS.
Forms an annular first core holding portion 12a1 having an inner diameter slightly smaller than the outer diameter of the core on the front end side in the tubular body 11, and further, the first core holding portion thereof. By providing a plurality of continuous protrusions in the circumferential direction on the rear side of the elastic portion 12 on the rear side of the second core holding portion 12a1, the second core holding portion 1 having a weaker frictional force to the core than the first advancing holding portion 12a1.
2a2 is formed. According to the slider 10C, the plurality of ridges intersect with the rotation direction of the residual core, so that it is possible to increase the frictional resistance against the residual core that is about to rotate.

Further, the slider 10D shown in FIG.
The holding force in the feeding direction of the lead is made smaller than the holding force in the retracting direction of the lead by the first lead holding portion 12a1 and the second lead holding portion 12a2 which are formed in a saw-tooth cross section. The second core holding portion 12a2 has a smaller number of saw-toothed ridges 14 in the axial direction than the first core holding portion 12a1 so that the second core holding portion 12a2 slides on the core with a frictional force weaker than that of the first core holding portion 12a1. I am doing it.

According to this slider 10D, when the lead is drawn out, the holding force is not too high, so that the lead-out operation of the lead is not supported, and at the time of writing, the lead is opposed to the writing pressure. Is strongly held, so that the remnant core can be prevented from being pushed back and rotating around the axis.

The slider 10E shown in FIG.
In the slider 10 described above, the elastic portion 12 is formed integrally with the tubular body 11 by insert molding, while the tubular body 11 'and the elastic portion 12' which are separate bodies are assembled. is there. In order to improve its assembling ability,
The above-mentioned cylindrical body 11 has a structure in which the rear edge portion 11a is omitted.

[0044]

Since the present invention is constructed as described above, it has the following effects. According to the first aspect of the invention, since the rear end surface of the residual core comes into contact with the front end surface of the succeeding core after the chuck is retracted, it is possible to avoid the phenomenon that the residual core retracts due to the gap between the residual core and the subsequent core during writing. It is possible to improve the feeling of writing when writing with the residual core. Therefore, it is possible to eliminate the operational inconvenience in the prior art of deliberately pulling out the residual core and feeding out the subsequent core, and by effectively using the residual core,
It is possible to reduce the amount of residual cores to be discarded. Furthermore, according to the second aspect of the invention, the movement amount of the lead that moves rearward as the slider moves backward can be minimized. Moreover, according to the third aspect of the invention, since the biasing means can be treated as a component integrated with the slider, component management is easy and the assemblability can be improved. Moreover, according to the fourth aspect of the invention, since the elastic portion integrally formed with the tubular body is provided with the biasing means and the core holding portion, it becomes easier to manage the parts, and the assembling property is further improved. Can be improved. Furthermore,
According to the fifth invention, since the assembly step after molding is unnecessary by insert molding, it is possible to improve the productivity of the slider, and moreover, since the core holding portion and the tubular body have good adhesion, The holding part does not fall off from the tubular body, and the parts management and the handling in the assembly process become easier. Moreover, according to the sixth invention, the second lead holding portion also slides on the lead with a weak frictional force on the first lead holding portion, so that the lead fed from the chuck can be smoothly guided to the writing tip portion, In addition, since the front end side of the lead is strongly held by the first lead holding portion during writing, the feeling of writing due to the residual lead can be further improved. Moreover, according to the seventh invention, the frictional force of the second core holding portion is weakened more easily and surely than the frictional force of the first core holding portion by bringing the flat inner surface into sliding contact with the core. be able to. Further, according to the eighth aspect, since the plurality of protrusions are provided so as to intersect with the rotation direction of the residual core, it is possible to increase the frictional resistance against the residual core that is about to rotate, and the residual core during writing. Can be more reliably prevented from rotating around the axis. Further, according to the ninth invention, when the lead is drawn out, the holding force of the lead holding portion is not too high, so that the lead-out operation of the lead is not supported. Since the core is strongly held against each other, it is possible to reliably prevent the writing feeling from being impaired by the residual core being pushed back or rotated around the axis.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an example of a mechanical pencil according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1, where (a) is a state in which a chuck is advanced, (b) is a state in which a trailing lead is retracted when the chuck is retracted, and (c) is a slider left. The state which slid back with a core is shown.

FIG. 3 is a perspective view showing an example of a slider.

FIG. 4 is a sectional view taken along line (IV)-(IV) in FIG.

5 is an end view taken along line (V)-(V) in FIG.

FIG. 6 is a perspective view showing another example of the slider.

FIG. 7 is a perspective view showing another example of the slider.

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

9 is an end view taken along line (IX)-(IX) in FIG.

FIG. 10 is a vertical cross-sectional view showing another example of the slider.

FIG. 11 is an exploded vertical sectional view showing another example of the slider.

FIG. 12 is a cross-sectional view of a main part of a conventional mechanical pencil, where (a) is a state in which a chuck is advanced, (b) is a state in which the chuck is retracted, and (c) is a writing pressure applied to a residual lead. Shows the state.

[Explanation of symbols]

10: slider 11: tubular body 12: Elastic part 12a: Lead holding part 12a1: first core holding part 12a2: second core holding part 12b: Energizing means 21: Chuck A: Mechanical pencil W: slide width

Claims (9)

[Claims] 1. A mechanical pencil in which a lead fed out by a chuck is inserted into a slider (registered trademark) located in a front opening, wherein the slider has a lead holding elastically holding the inserted lead. It is configured to slide forward when pressed by the chuck, and to be biased by the biasing means and slidably contact the inside of the front opening, so that the chuck slides backward after the chuck retreats. A mechanical pencil that is characterized. 2. The sliding width of the slider, which is biased by the biasing means and slides, is set to be substantially the same as the retracting width of the lead which is slightly retracted when the chuck is retracted. The mechanical pencil according to claim 1. 3. The urging means is formed integrally with the slider, and is provided so that the outer peripheral surface of the urging means is slidably contacted with the inside of the front opening. mechanical pencil. 4. The slider comprises a tubular body slidable in an axial direction and an elastic portion integrally made of an elastic material, the elastic portion including the urging means and the core holding portion. The mechanical pencil according to any one of claims 1 to 3, wherein the mechanical pencil is provided integrally. 5. The elastic portion is formed in the tubular body by insert molding.
The described mechanical pencil. 6. The lead holding portion comprises a first lead holding portion formed on the front end side of the slider and a second lead holding portion formed on the rear side of the second lead holding portion, The mechanical pencil according to any one of claims 1 to 5, wherein the second lead holding portion is formed so as to be in sliding contact with the lead with a frictional force weaker than that of the first lead holding portion. 7. The mechanical pencil according to claim 6, wherein the second lead holding portion is formed in a polygonal shape in cross section, and a flat inner surface thereof is brought into sliding contact with the lead. 8. The mechanical pencil according to claim 6, wherein the second lead holding portion is provided with a plurality of projections continuous in the axial direction in the circumferential direction. 9. The lead holding portion is formed so that the holding force in the feeding direction of the lead is smaller than the holding force in the retracting direction of the lead. The described mechanical pencil.