JPH0356386Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention automatically advances the lead by the distance worn by writing, and when the lead is worn out during writing, a spare lead automatically follows. This invention relates to an automatic mechanical pencil.

2. Description of the Related Art Conventionally, there has been published Japanese Patent Application Laid-Open No. 59-93396 as an automatic mechanical pencil in which the lead is automatically fed out by the distance worn by writing, and the lead is automatically followed by a spare lead. A compression spring is provided between a clamping member that holds the core and a core guide tube, and the compression spring forms a working connection for transmitting pressure between the core guide tube and the clamping member. It is.

Problems to be solved by the invention Therefore, in the conventional method, when the core inner tube, which has been retracted due to wear of the core, is advanced by a compression spring, the core slides on the core clamp holder closed by the compression spring and moves forward. This made the feeding of the lead very uncertain.

Means for Solving the Problems The structure of the present invention to achieve the above purpose is as follows:
To explain using FIGS. 1 to 4 corresponding to the embodiment, the present invention has a base 2 screwed onto a shaft 1,
A first spring 5 is provided between the core guide pipe 3 and the spring receiver 4 which are loosely fitted therein, and the head 9A of the chuck 9 is positioned between the first spring 5 and the tapered surface 1A of the shaft 1. Further, a ball 10 is rotatably attached to a recessed portion 9B provided in the head 9A of the chuck 9, and normally the first spring 5 is extended to a free length and the chuck 9 is expanded. . Furthermore, a lead holder 7 that lightly holds the lead 6 is loosely fitted into the recess 3B of the lead guide pipe 3, and a second spring 8 is stretched between the rear end of the lead holder 7 and the inner stage 3C of the lead guide pipe 3. to propel the lead holder 7 forward in the axial direction. Moreover, the spring constant of this second spring 8 is smaller than the spring constant of the first spring 5, and the second spring 8
The elastic force of is set to be weaker than the lead holding force of the lead holder 7.

Function Next, the function of the present invention will be explained. When writing is performed from the state shown in FIG.
The chuck 9 is pushed back by the front end of the chuck 9. Then, the ball 10 attached to the chuck 9 comes into contact with the tapered surface 1A of the shaft 1, and the chuck 9 is closed, and the core 6 is strongly held by the chuck 9, resulting in the state shown in FIG. 2. If you write in this state, the lead guide pipe 3 will move to the first position as the lead 6 wears out.
The spring 5 is compressed and moved backward, resulting in the state shown in FIG. Next, when writing is finished and the lead guide pipe 3 is released from the paper surface, the lead guide pipe 3 is moved forward by the elastic force of the compressed first spring 5. However, since the elastic force of the first spring 5 also acts on the chuck 9, the chuck 9 cannot expand and continues to hold the core 6. Moreover, the spring constant of the second spring 8 is smaller than that of the first spring 5, and the second spring has a lower spring constant than the lead holding force of the lead holder 7.
Since the elastic force of the spring 8 is set weak, even if the core guide pipe 3 moves forward, the core holder 7
stops together with the core 6, and the second spring 8 is compressed. When the first spring 5 is fully extended to its free length, a gap is created between the spring receiver 4 and the chuck 9, and the chuck 9 expands due to the elasticity of the chuck 9 itself. Then the second
Due to the elastic force of the spring 8, the lead holder 9 is moved forward while holding the lead 6, and returns to the state shown in FIG. At this time, if the lead 6 wears out and becomes short due to writing, it will come out in front of the chuck 9 when the lead 6 is advanced by the lead holder 7, but in this case, the automatic feeding type sharp pencil When the leading end of the lead 6 is directed downward, the spare lead 12 is inserted into the chuck 9 by its own weight and comes into contact with and follows the shortened rear end of the lead 6.

Example Figure 1 shows an example of this invention.
A cap 2 is screwed onto the front part of the shaft 1, and a core guide pipe 3 is loosely fitted into the cap 2 so as to be slidable in the axial direction. A first spring 5 extending to a free length is provided between the outer stage 3A of the core guide pipe 3 and the outer stage 4A of the spring receiver 4, and the tip of the core guide pipe 3 protrudes appropriately from the tip hole 2A of the base 2. ing. A lead holder 7 that lightly holds the lead 6 is loosely fitted into the recess 3B of the lead guide pipe 3 so as to be able to slide back and forth in the axial direction, and the rear end of the lead holder 7 is connected to the inner stage 3C of the lead guide pipe 3. The lead holder 7 is elastically pushed forward in the axial direction by the elastic force of the second spring 8 stretched therebetween. Moreover, the spring constant of this second spring 8 is smaller than the spring constant of the first spring 5,
In addition, the elastic force of the second spring 8 is set to be weaker than the lead holding force of the lead holder 7. The head 9A of the chuck 9 is located between the spring receiver 4 and the tapered surface 1A provided at the front of the shaft 1, and the ball 10 rolls into the concave portion 9B provided in the head 9A of the chuck 9. movably mounted. At this time, a slight gap is provided between the spring receiver 4 and the front end of the chuck 9, and the chuck 9 is configured to expand due to its own elasticity. A spare lead 12 is stored between the funnel-shaped part 9C formed at the rear of the chuck 9 and the eraser 11 fitted at the rear of the shaft 1, and if the tip of the automatic mechanical pencil is turned downward, The funnel-shaped portion 9C of the chuck 9 sequentially follows the spare lead 12. Furthermore, a knob 13 is fitted to the rear of the shaft 1 so as to cover the eraser 11.

Next, the operation of this embodiment will be explained. When the tip of the lead guide pipe 3 is pressed against the paper surface for writing from the state shown in FIG. 1, the lead guide pipe 3 moves back slightly and the spring receiver 4 comes into contact with the front end of the chuck 9. Then, the ball 10 provided on the head 9A of the chuck 9 rolls along the tapered surface 1A of the shaft 1, and the chuck 9 is closed to the state shown in FIG. 2, holding the lead 6. If you write in this state, the lead 6 will wear out and the lead guide pipe 3 will
However, as the first spring 5 is compressed, the lead holder 7 slides on the lead 6 and retreats, resulting in the state shown in FIG. 3. Next, when writing is stopped and the lead guide pipe 3 is released from the paper surface, the lead guide pipe 3 is moved forward by the elastic force of the compressed first spring 5. However, at this time, since the spring receiver 4 is brought into contact with the chuck 9 by the first spring 5, the chuck 9 cannot expand and continues to hold the core 6. Moreover, the spring constant of the second spring 8 is smaller than that of the first spring 5, and the core holder 7
Since the elastic force of the second spring 8 is set to be weaker than the lead holding force of the lead guide pipe 3, the lead holder 7 stops together with the lead 6 and the second spring
The spring 8 is compressed to the state shown in FIG. When the first spring 5 is fully extended to its free length, a gap is created between the spring receiver 4 and the chuck 9. Then, due to the elastic force of the chuck 9 itself trying to expand, the ball 10 provided on the head 9A of the chuck 9 rolls along the tapered surface 1A of the shaft 1, and the chuck 9 expands and the core 6 to release. Then, due to the elastic force of the second spring 8, the lead holder 7 is moved forward while holding the lead 6, and returns to the state shown in FIG. 1. At this time, by writing, lead 6
If the lead 6 is worn and shortened, when the lead 6 is advanced by the lead holder 7, the lead 6 will become the chuck 9.
It will come out further forward, but in this case, if you point the self-feeding sharp pencil downward, you can remove the spare lead 1.
2 is guided by its own weight to the funnel-shaped portion 9C of the chuck 9 and inserted into the chuck 9, and the end surface of the preliminary lead 12 is brought into contact with the shortened rear end of the lead 6. Therefore, writing can be done by simply pressing the lead guide pipe 3 that guides the lead 6 against the paper surface without artificially drawing out the lead 6 or having the spare lead 12 follow it, and each lead 6 can be shortened. Even if the lead 6 becomes short, the spare lead 12 is successively followed and brought into contact with the rear end of the shortened lead 6, so even if the lead 6 becomes short, writing can be performed without retreating.

FIG. 5 shows another embodiment of this invention, in which a base 102 is screwed onto the front part of a shaft 101, and a core guide pipe 103 is loosely fitted into the base 102 so as to be slidable in the axial direction. ing. Core guide pipe 103
The front part of the first spring 105 is press-fitted into the rear part of the spring receiver 104, and the first spring 105 is press-fitted into the rear part of the
The rear part of the spring 105 is press-fitted, and the first spring 105 extends to its free length. Furthermore, the third spring 14 is stretched between the outer stage 103A of the core guide pipe 103 and the inner stage 102B of the base 102, so that the tip of the core guide pipe 103 appropriately protrudes from the tip hole 102A of the base 102. . A lead holder 107 that lightly holds the lead 106 is loosely fitted into the recess 103B of the lead guide pipe 103 so as to be slidable back and forth in the axial direction.
The rear end of 07 and the inner stage 103 of the core guide pipe 103
The lead holder 107 is elastically pushed forward in the axial direction by the elastic force of the second spring 108 stretched between the second spring 108 and the second spring 108. Moreover, this second spring 108
The spring constant of the first spring 105 is smaller than that of the first spring 105, and the elastic force of the second spring 108 is set to be weaker than the core holding force of the lead holder 107. A magnet 15 is fixed to the rear end of the spring receiver 104, and a chuck 109 is made of a magnetic material.
01A, head 1 of chuck 109
The ball 11 is placed in the concave portion 109B provided in 09A.
0 is rotatably mounted. At this time, the front end of the chuck 109 is attracted to the magnet 15 fixed to the spring receiver 104, the core guide pipe 103 is biased forward by the third spring 14, and the first spring 105 is extended to its free length. The chuck 109 is biased forward and expanded.

In the case of this embodiment, since the chuck 109 is forcibly biased forward and expanded by the magnet 15, the spare core 112 can be reliably followed inside the chuck 109. Further, writing operations can be performed in exactly the same manner as in the embodiment shown in FIG.

FIG. 6 shows another embodiment of this invention, in which a base 202 is screwed onto the front part of a shaft 201, and a core guide pipe 203 is loosely fitted into the base 202 so as to be slidable in the axial direction. ing. Core guide pipe 203
The outer stage 203A of the spring receiver 204 and the outer stage 20 of the spring receiver 204
4A is provided with a first spring 205 extending to a free length, and the tip of the core guide pipe 203 protrudes appropriately from the tip hole 202A of the base 202. A lead holder 207 that lightly holds the lead 206 is loosely fitted into the recess 203B of the lead guide pipe 203 so as to be able to slide back and forth in the axial direction.
The rear end of 07 and the inner stage 203 of the core guide pipe 203
The lead holder 207 is elastically pushed forward in the axial direction by the elastic force of the second spring 208 stretched between the second spring 208 and the second spring 208. Moreover, this second spring 208
The spring constant of the first spring 205 is smaller than that of the first spring 205, and the elastic force of the second spring 208 is set to be weaker than the core holding force of the lead holder 207. A head 209A of a chuck 209 is located between the spring receiver 204 and a tapered surface 201A provided at the front of the shaft 201.
A ball 210 is rotatably attached to a concave portion 209B provided in a head portion 209A of the ball 9.
Furthermore, the outer flange 209D of the chuck 209 and the shaft 201
A first spring 205 is provided between the inner stage 201B and the inner stage 201B.
A fourth spring 16 with a weaker elastic force is stretched, and the front part of the chuck 209 is usually connected to the spring receiver 2.
04, the chuck 209 is expanded by its own elasticity.

In the case of this embodiment, since the chuck is forcibly biased forward and expanded by the fourth spring, it is possible to reliably cause the spare lead to follow inside the chuck. Further, writing operations can be performed in exactly the same manner as in the embodiment shown in FIG.

Effects of the invention As explained above, the present invention provides a first spring that extends to a free length between the core guide pipe loosely fitted in the base and the spring receiver, and also lightly inserts the core into the recess of the core guide pipe. A lead holder to be held is loosely fitted, and a second spring is stretched between the rear end of the lead holder and the inner stage of the lead guide pipe to spring the lead holder forward in the axial direction. Moreover, this second
The advantage is that the spring constant of the spring is smaller than that of the first spring, and the elastic force of the second spring is weaker than the core holding force of the lead holder. Therefore, when the lead guide pipe, which had retreated as the lead wore out due to writing, was moved forward by the first spring, the first spring reached its free length and the chuck expanded, even if the lead held by the chuck did not move forward. Afterwards, the lead holder is advanced by the second spring and the lead is drawn out. In other words, even if the chuck has a strong holding force on the lead, the lead can be reliably drawn out. Also, usually the first
Since the spring is extended to a free length, the chuck is expanded, and if one core becomes short, a spare core can follow at any time.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing the self-feeding mechanical pencil of the present invention, Fig. 2 is a vertical cross-sectional view showing the automatic feeding mechanical pencil of Fig. 1 in a writing state, and Fig. 3
The figure is a vertical cross-sectional view of the main parts of the self-feeding sharp pencil shown in Figure 1, showing the state in which the lead has been worn out due to writing.
FIG. 4 is a vertical sectional view of the main part of the self-feeding sharp pencil shown in FIG. 1, showing the state in which the lead guide pipe is moving forward, and FIGS. FIG. 1,101,201...axis, 1A, 101A,
201A...Tapered surface of shaft 1, 101, 201, 201B...Inner stage of shaft 201, 2, 102,
202...cap, 2A, 102A, 202A...
Tip hole of cap 2, 102, 202, 102B...
Inner stage of base 102, 3, 103, 203... Core guide pipe, 3A, 103A, 203A... Outer stage of core guide pipe 3, 103, 203, 3B, 1
03B, 203B... Core guide pipe 3, 10
3,203 recesses, 3C, 103C, 203C...
...Inner stage of core guide pipe 3, 103, 203,
4,104,204...Spring receiver, 4A,2
04A...Spring receiver 4, outer stage of 204, 5,
105,205...first spring, 6,10
6,206...core, 7,107,207...core holder, 8,108,208...second spring, 9,109,209...chuck, 9A,1
09A, 209A...Chick 9, 109, 20
9 head, 9B, 109B, 209B... recessed part of chuck 9, 109, 209, 9C... funnel shaped part of chuck 9, 209D... outer rim of chuck 209, 10, 110, 210... ball, 11...
...Eraser, 12,112...Spare lead, 13...
Knob, 14...Third spring, 15...Magnet,
16...Fourth spring.

Claims (1)

[Scope of utility model registration request] In an automatic sharp pencil, in which the lead is automatically fed out sequentially as the lead wears out, a lead guide pipe and a spring holder are built into the base of the shaft so as to be slidable in the axial direction, and the lead guide pipe and spring The first part extends to a free length between the receiver and the receiver.
By providing a spring, the tip of the lead guide pipe protrudes from the tip hole of the base as appropriate, and the lead holding force of the lead holder is increased between the lead holder, which is loosely fitted into the recess of the lead guide pipe, and the inner stage of the lead guide pipe. A second spring that is weak and has a spring constant smaller than that of the first spring is stretched, and the head of the chuck is positioned between the spring receiver and the tapered surface of the shaft that gradually tapers toward the rear in the axial direction. The head of the chuck is configured to be openable and closable, and the ball is rotatably mounted in a recess provided in the head, and when the first spring is extended to its free length, the head of the chuck is expanded. A self-feeding sharp pencil characterized by a structure that allows the lead to pass through.