JP6706132B2 - mechanical pencil - Google Patents

Description

The present invention relates to a mechanical pencil, and more particularly to a mechanical pencil having a structure in which a certain amount of core is fed out as the core wears during writing.

Conventionally, Patent Document 1 is known as a mechanical pencil that is automatically filed by an amount in which a lead is worn, as filed by the applicant of the present application.

However, in the structure of Patent Document 1, the tip of the lead guide pipe comes into contact with the writing surface during writing, the lead guide pipe retracts, and when writing is interrupted and the tip of the lead guide pipe is separated from the writing surface, the lead holder moves. Since the built-in lead guide pipe moves forward while advancing while holding the lead, the tip of the lead guide pipe is in contact with the writing surface together with the lead in most of the writing, impairing the writing feeling.

As a structure for solving this problem, Patent Document 2 has a structure in which the tip of a sliding unit that serves as a core guide is prevented from abutting during writing by extending the core by applying and releasing writing pressure applied to the core during writing. An automatic drawing type mechanical pencil is described.
As a structure of Patent Document 2, a structure in which a chuck unit for preventing the retreat of the lead and a sliding unit for holding the lead are arranged in the barrel is illustrated in the third embodiment, and the writing pressure is applied to the lead during writing. Since the sliding unit that serves as the core guide retracts together with the core when the contact is applied, the sliding unit does not contact the writing surface and the writing feeling is not impaired. Further, in the present structure, a cylindrical member having a plurality of saw tooth-shaped cam ridges formed on the rear end surface and the tip member of the sliding unit, and having a projection engaging with the saw tooth-shaped cam ridges is used to move the sliding unit back and forth. By rotating and moving back and forth and intermittently moving the cylinder member back and forth, it is configured that the lead is drawn out once by a plurality of writing pressures, and it is possible to prevent the lead out more than necessary. it can. Furthermore, with this structure, depending on the usage of the mechanical pencil, the hardness and paper quality of the core to be written, the wear of the core due to the language to be written, etc. It can be set.
However, in the structure of Patent Document 2, depending on the usage of the mechanical pencil, the hardness of the core to be written on, the quality of the paper, the wear of the core due to the language to be written, etc. Although it can be manufactured by setting it, it cannot respond to the situation change during use after manufacturing, so if you use it differently from the setting, the core will come out too much from the tip of the sliding unit when writing and the core will break. Sometimes occurred.

Japanese Utility Model Publication 60-21273 International publication WO2012/014832

The present invention has been made in view of the above problems, and an object of the present invention is to provide a mechanical pencil that can switch between a state in which a lead is extended and a state in which it is not extended by applying and releasing writing pressure. .

The present invention is
“1. In the shaft cylinder, a lead feeding mechanism that allows the lead to move forward but prevents the lead from retracting, and a slide member that holds the lead with an appropriate force,
A mechanical pencil for feeding out the lead by applying and releasing writing pressure applied to the lead,
A rear portion of a tip member that encloses the slide member is disposed in the barrel.
The tip member is configured to be unrotatable and movable back and forth with respect to the barrel.
A rotary member provided with a front cam at the front is disposed behind the tip member,
The rotating member is configured to be rotatable and movable back and forth with respect to the barrel.
A rear cam that engages with a front cam of the rotating member, is provided at a rear portion of the front member,
A fixed cam that engages with the front cam of the rotating member is provided on the inner surface of the barrel;
A spring that elastically pushes the slide member forward is disposed between the slide member and the tip member,
On the side surface of the tip member or the barrel, a slide blocking portion that blocks the forward and backward movement of the tip member with respect to the barrel is provided.
By applying and releasing the writing pressure applied to the core, the front member moves back and forth with respect to the shaft cylinder, and the front cam of the rotating member engages with the rear cam of the front member and the fixed cam of the shaft cylinder. By doing so, the rotating member rotates and the core is fed out,
A mechanical pencil, characterized in that by operating the sliding prevention portion, the forward and backward movement of the tip member with respect to the barrel in applying and releasing the writing pressure applied to the core is prevented.
2. 2. The mechanical pencil according to item 1, wherein the sliding prevention portion of the tip member is formed in a convex shape or a concave shape on the outer surface of the tip member or the barrel.
3. The rear cam at the rear of the tip member and the fixed cam on the inner surface of the barrel are formed by saw-toothed cam lobes,
The rear cam of the front member and the fixed cam on the inner surface of the barrel are configured to move back and forth in a state of being out of phase with each other,
The cam mountain of the fixed cam of the shaft cylinder has a deep valley portion and a shallow valley portion,
The rotary member is rotated by applying and releasing the writing pressure applied to the core,
When the cam crest of the front cam of the rotating member engages with the deep trough of the fixed cam of the shaft cylinder, the tip member largely moves back and forth to extend the core,
3. The sharpening device according to claim 1 or 2, wherein when the cam crest of the front cam of the rotating member engages with the shallow trough of the fixed cam of the barrel, the core is not extended. Pencil. It is.

The mechanical pencil of the present invention can be used as a normal mechanical pencil because, when writing is performed with the sliding prevention portion being operated, the forward and backward movement of the tip member is prevented and the core is not extended by the writing pressure. Further, when the core becomes short, the core is automatically paid out by writing pressure by releasing the hand from the sliding prevention portion.
In addition, since the slider is configured to be movable back and forth with respect to the tip member, when the core wears during writing and the slider comes into contact with the paper surface and retracts, a normal automatic mechanical pencil as in the prior art 1 is used. Similarly, when the writing pressure is released and the slider moves forward, it is possible to automatically feed the lead.

Further, operating the sliding prevention portion includes operations of gripping, pushing, sliding, and rotating the sliding prevention portion with a hand. It suffices if the members cannot slide. At this time, the sliding prevention portion may be formed on the outer surface of the front member or the outer surface of the barrel.
When the sliding prevention portion is operated by gripping, it is preferable that the sliding prevention portion is formed in a convex shape or a concave shape on the outer side surface so that it can be easily gripped so as to prevent slipping. Further, the sliding prevention portion may have a convex shape or a concave shape as long as it can be easily grasped, but it is more preferable to form a plurality of them in parallel to prevent slipping.
Further, the sliding prevention portion may be formed in a switch shape so as to be slidable inward of the shaft cylinder, and by pushing the sliding prevention portion, the shaft cylinder and the front member are locked and the front member is It may be configured so that it cannot slide.

In the present invention, a shallow valley portion and a deep valley portion are formed in the cam mountain of the fixed cam of the shaft cylinder, and the composition ratio of the shallow valley portion and the deep valley portion is changed, whereby the writing pressure applied to the core is released and released. It is possible to change the rate at which the lead is paid out. For example, if the core is to be extended once by applying the writing pressure twice, it is sufficient to alternately form the shallow valley portion and the deep valley portion, and in the case of extending the core once every 10 times. It is only necessary to form nine shallow valleys and then form one deep valley.

According to the present invention, by providing the sliding prevention portion on the side surface of the tip member or the barrel, the mechanical pencil can be easily switched between the state in which the lead is extended and the state in which it is not extended by applying and releasing the writing pressure. I was able to.

It is a side view of the mechanical pencil of a present Example. It is a longitudinal cross-sectional view of the mechanical pencil of the present embodiment. It is sectional drawing which expanded the principal part of a present Example. It is sectional drawing in the AA line of FIG. FIG. 4 is an enlarged schematic side view showing the relationship between the front cam of the rotary member, the fixed cam of the barrel, and the rear cam of the front member in FIG. 3. It is a longitudinal cross-sectional view of the mechanical pencil of the present embodiment. FIG. 7 is a schematic side view showing the relationship between the front cam of the rotary member of the mechanical pencil of this embodiment, the fixed cam of the shaft cylinder, and the rear cam of the front member, and FIG. 7( a) is FIG. 3 and FIG. 6), FIG. 7(c) is FIG. 8, and FIG. 7(d) is a schematic side view showing the relationship between the cams in FIG. It is a longitudinal cross-sectional view of the mechanical pencil of the present embodiment. It is a longitudinal cross-sectional view of the mechanical pencil of the present embodiment. It is a longitudinal cross-sectional view of the mechanical pencil of the present embodiment.

Hereinafter, the mechanical pencil of the present embodiment will be described with reference to the drawings, but the present invention is not limited to the mechanical pencils described below.
In the present embodiment, the side with the writing tip is expressed as the front, and the opposite side is expressed as the rear. The side closer to the axis of the barrel is expressed as the inner side, and the opposite side is expressed as the outer side.

1 is a side view of the mechanical pencil of the present embodiment, FIG. 2 is a vertical sectional view of the mechanical pencil of FIG. 1, FIG. 3 is an enlarged vertical sectional view of a main part, and FIG. It is sectional drawing in the AA line of FIG. As shown in FIGS. 1 and 2, a mechanical pencil 1 includes a front shaft member 2 formed in a tubular shape, a rear shaft member 3 screwed to a rear portion of the front shaft member 2, and a front side of the front shaft member 2. A front member 4 inserted through the opening and a cap 5 attached to the rear portion of the rear shaft member 3 are provided. Further, a tip opening 4a through which the slide member 6 can be inserted is formed at the tip of the tip member 4. Further, a tip hole portion 6a through which the core 7 can be inserted is formed at the tip of the slide member 6.
In this embodiment, the front barrel member 2 and the rear barrel member 3 form the barrel 8.

As shown in FIGS. 2 and 3, a ball chuck 9 having a head portion 9a divided into two is disposed inside the shaft cylinder 8, and a hemispherical concave portion 9b is provided on an outer surface of the head portion 9a. Is formed. A spherical steel ball 10 is inserted into the recess 9b of the ball chuck, and a tubular fastener 11 is provided so as to surround the steel ball 10 and the ball chuck 9.
Further, a slanted portion 11a is formed on the inner surface of the front part of the fastener 11 so as to expand toward the front. The slanted portion 11a is arranged so that the steel ball 10 inserted into the recess 9b of the ball chuck 9 is brought into contact therewith. I am doing it.
Further, a step portion 9c is formed on the outer side surface of the ball chuck 9, and the chuck spring 12 is stretched between the step portion 9c and the inner step formed on the inner surface of the fastener 11 so that the ball chuck 9 is attached. It is bulged backward with respect to the fastener 11.

A cylindrical connector 13 having an inner hole through which the core 7 can pass is disposed behind the ball chuck 9, and when the connector 13 advances, the rear end of the ball chuck 9 and the front end of the connector 13 contact each other. It is arranged so that it touches.

A sliding cylinder 14 is arranged in the intermediate portion 13a of the connector 13, and the sliding cylinder 14 is attached to the connector 13 so as to be movable back and forth. Further, the front end of the sliding cylinder 14 is in contact with the rear end of the fastener 11, and the knocking spring 15 is stretched between the rear part of the sliding cylinder 14 and the rear step part of the connector 13 so that the sliding cylinder 14 extends. The connector 13 is bulged backward with respect to 14.
A cylindrical lead tank 16 is press-fitted in the rear portion of the connector 13, and an eraser 17 is detachably attached to the inner hole of the rear portion of the lead tank 16 so as to be rearward from the rear inner hole of the rear shaft member 3. A cap 5 is removably attached to the outer surface of the rear portion of the lead tank 16 projecting toward.

This embodiment employs a general ball-chuck type lead-out mechanism in which the steel ball 10 is sandwiched between the ball chuck 9 and the fastener 11 as described above. At this time, when the lead 7 retreats, the wedge action works and strongly clamps the lead 7, but when the lead 7 advances, the wedge action is released and the lead 7 can be pulled out with a small force.

A tubular front tubular body 18 is disposed inside the shaft barrel 8 and outside the fastener 11, and a window portion 18a formed on a rear side surface of the front tubular body 18 and a sliding barrel 14 are provided. The front cylindrical body 18 and the sliding cylinder 14 are integrally fixed by locking the claw portion 14a formed so as to project outward from the outer surface of the front cylindrical body 18 and the sliding cylinder 14.
A step portion 18b is formed in the front inner hole of the front tubular body 18, and when the fastener 11 moves forward, the outer step portion 11b formed on the outer surface of the fastener 11 and the step portion of the front tubular body 18 are formed. The forward movement of the fastener 11 is regulated by making it contact with 18b. Further, a slit portion 18c penetrating the inside and the outside and extending in the axial direction is formed on the side surface of the front tubular body 18.

As shown in FIGS. 2, 3 and 4, the front cylindrical body 18 is inserted in the rear inner hole 4c of the front member 4 inserted from the front opening of the front shaft member 2 so as to be movable back and forth. Further, side holes 4d penetrating the inside and the outside are formed on the side surface of the tip member 4 at two positions diagonally with the axial center interposed therebetween. A key member 19 having a brim portion 19a formed in a nail shape is press-fitted and fixed to the side hole 4d, and the tip of the key member 19 projects inward from the inner surface of the tip member, and the projecting projection By inserting the portion 19b into the slit portion 18c of the front tubular body 18, the front tubular body 18 can be moved back and forth with respect to the front member 4 and cannot be rotated.
Further, the collar portion 19a of the key member 19 is press-fitted in a state of protruding outward from the outer surface of the tip member 4, and the collar portion 19a is formed in the lateral hole portion 2a formed by extending the side surface of the front shaft member in the axial direction. By arranging the front shaft member 2, the front member 4 is configured to be movable back and forth and not rotatable.
As a result, the front tubular body 18 can move back and forth with respect to the front member 4 only by the gap between the protruding portion 19b of the key member 19 and the front and rear protruding portion 19b in the slit portion 18c of the front tubular body 18. Reference numeral 4 is configured so that the flange portion 19a of the key member 19 can be moved back and forth with respect to the front shaft member only by a gap in the front and rear direction in the lateral hole portion 2a of the front shaft member 2.

Further, an intermediate spring 20 is stretched between the inner stage 4b of the front member 4 and the front end of the front cylindrical body 18, and the front member 4 is elastically bulged forward with respect to the front cylindrical body 18.

Further, as described above, the slide member 6 is disposed inside the tip member 4, and the stopper 21 is press-fitted into the intermediate inner hole of the tip member 4 so as to surround the slide member 6 from the rear of the slide member 6. I am doing it.
A front spring 22 is stretched between the intermediate step portion 6b of the slide member 6 and the outer step portion 21a of the stopper 21 to elastically push the slide member 6 forward with respect to the tip member 4.

Further, as shown in FIG. 1, the outer surface 4e of the tip member 4 is provided with a plurality of protrusions 4f (sliding-preventing portions) protruding outward in a state of being aligned in the axial direction, The plurality of protrusions 4f are formed to be gradually higher toward the front, so that when gripped by a hand, the fingers are not caught and slippery, and the operation is easy.
In the present embodiment, the protrusion 4f is formed on the outer surface of the tip member 4 by using two-color molding, and an elastic synthetic resin such as elastomer or synthetic rubber such as silicon rubber is used as a material. Therefore, it is formed so as to be more slippery.

As shown in FIGS. 2, 3 and 5, a rear cam 4g is formed at the rear end portion of the front member 4 in a saw-tooth shape toward the rear, and the rear cam 4g is formed in a circumferential shape. It is composed of a plurality of cam mountains 4h.

A core holder 23 made of synthetic rubber that holds the core 7 with an appropriate force is built in the inner hole of the slide member 6. Silicon rubber, nitrile rubber, or the like can be adopted as the synthetic rubber that constitutes the core holder 23, and in this embodiment, it is formed of silicon rubber.
The core holding force of the core holder 23 is set to be stronger than the force of pulling the core forward when the ball chuck 9 holds the core 7 and weaker than the force of pushing the core backward.

On the inner surface of the front shaft member 2, a fixed cam 2c formed by a saw-like cam lobe 2b is provided rearward so as to be adjacent to the rear cam 4g of the front member 4, and the fixed cam 2c is The front member 4 is formed with the same pitch as the rear cam 4g and with a phase shift of half.
Further, the fixed cam 2c is formed so that shallow valleys 2d and deep valleys 2e, which are cam peaks having different depths, are continuously and alternately arranged. Further, the shallow valley portion 2d and the deep valley portion 2e are formed at equal pitch intervals.

A rotating member 24 formed in a tubular shape is disposed behind the front member 4 and outside the front cylindrical body 18, and the rotating member 24 is rotatable with respect to the front cylindrical body 18 and the front shaft member 2. Is formed. Further, a front cam 24a having a width capable of contacting both the fixed cam 2c of the front shaft member 2 and the rear cam 4g of the front member 4 simultaneously with the front end of the rotary member 24 is formed in a saw blade shape toward the front. The front cam 24a of the rotating member 24 is formed with a pitch interval which is twice the pitch of the rear cam 2g of the front shaft member 2 and the rear cam 4g of the front member 4, and the deep valley of the fixed cam 2c of the front shaft member. It is composed of the same number of cam ridges 24b as the portion 2e.
In the present invention, 12 deep valleys 2e are formed and 12 shallow valleys 2d are formed. Therefore, the cam ridges 24b of the rotating member 24 are also formed in the same number of 12 places as the deep valleys 2e. ..

Further, a washer 25 is disposed behind the rotary cam 24, and the front end of the washer 25 is configured to contact the rear end of the rotary member 24. Further, the washer 25 is formed so that the cross-sectional shape of the tip thereof is arcuate so that the contact area with the rotating member 24 is reduced, so that the washer 25 does not easily rotate when the rotating member 24 rotates.

A rear tubular body 26 formed in a tubular shape is disposed behind the front tubular body 18, and the front end inner circumferential portion of the rear tubular body 26 is press-fitted and fixed to the rear end outer circumferential portion of the front tubular body 18. The front cylinder 18 and the rear cylinder 26 are integrally fixed.
Further, by stretching the rear spring 27 between the outer step portion 26a of the rear tubular body 26 and the rear end of the washer 25, the washer 25 and the rotating member 24 are elastically bulged forward with respect to the rear tubular body 26. is there. Since the rotating member 24 is elastically urged forward by the rear spring 27, the front cam 24a of the rotating member 24 is in contact with the fixed cam 2c of the front shaft member 2 when being carried.
Further, by stretching the writing pressure receiving spring 28 between the inner step portion 26b of the rear tubular body 26 and the front inner step 3a of the rear shaft member 3, the rear tubular body 26 is elastically moved forward with respect to the axial tube 8. Has been issued.

Next, with reference to FIG. 3, FIG. 5, FIG. 6, FIG. 7, FIG. 8 and FIG. 9, the core 7 protruding from the tip end hole portion 6a of the slide member 6 is written by writing with the Erb pencil 1 in the state of FIG. A state in which the lead 7 is unwound when the lead 7 is worn and the writing pressure applied to the lead 7 is released and released will be described.
In the mechanical pencil 1 of the present invention, when the shaft cylinder 8 is gripped in the state shown in FIG. 3 and the projection 4f (sliding prevention part) of the tip member 4 is simultaneously gripped for writing, the tip member is pressed at the same time as the writing pressure. When the pushing force acts on the front side, it means that the protrusion 4f (sliding prevention part) is operated, and it is possible to prevent the front member 4 from moving back and forth with respect to the shaft cylinder 8. The core 7 will not be automatically paid out even if it is written as long as it does not touch. For this reason, when the protrusion 4f is gripped by hand, the core 7 protruding from the tip end hole 6a of the slide member 6 is gradually worn by writing.
When the core 7 is worn, remove the hand from the protrusion 6f, hold only the barrel 8 and press the core 7 against the paper surface to perform the first writing, and the ball chuck 9 and the fastener 11 that receive the writing pressure. , The connector 13, the sliding cylinder 14, the front cylindrical body 18, and the rear cylindrical body 26 are stopped, but when the writing pressure exceeds the elastic force of the writing pressure receiving spring 28, it is gripped by hand with the tip member 4. The shaft cylinder 8 advances with respect to the front cylinder body 18. Here, when the protruding portion 19b of the key member 19 comes into contact with the slit portion 18c of the front cylindrical body 18, the forward movement of the tip member 4 is restricted and stopped, but the shaft cylinder 8 further advances and the collar of the key member 19 is stopped. When the part 19a comes into contact with the rear end of the lateral hole 2a of the front shaft member 2 that has moved forward, or when the rear part of the front member 4 comes into contact with the inner stage of the front shaft member 2, the forward movement of the barrel 8 is restricted. Stop. At this time, since the slide member 6 holds the lead 7 by the lead holder 23, the slide member 6 does not move, but the front spring 22 is compressed by the amount of the forward movement of the front member 4 and is urged forward as shown in FIG. Become.
Further, FIG. 7A shows a positional relationship among the front cam, the rear cam, and the fixed cam 2c in the state of FIG. 3, and when the barrel 8 moves forward from the state of FIG. When the fixed cam 2c formed on the inner surface of the shaft member 2 moves forward and the contact between the cam crest 24b of the front cam 24a of the rotating member 24 and the deep trough 2e of the cam crest of the fixed cam 2c is released, the front cam 2c is released. Since 24a is elastically bulged forward, the cam crest 24b of the front cam 24a slides half the cam crest 4h of the rear cam 4g of the front member 4 and the rotary member rotates counterclockwise by a half phase, as shown in FIG. The state of b) is obtained.

Here, when the writing is stopped and the writing pressure on the lead 7 is released to separate the lead 7 from the paper surface, the ball chuck 9, which is urged forward by the elastic force of the writing pressure receiving spring 28, against the barrel 8. The fastener 11, the connector 13, the sliding cylinder 14, the front cylinder 18 and the rear cylinder 26 move forward. Then, as the front tubular body 18 advances, the front member 4 also advances, and the state shown in FIG. 8 is obtained. At this time, when the front member 4 moves forward from the state shown in FIG. 7B, the rotary member 24 elastically pushed forward by the rear spring 27 also moves forward, but the cam of the front cam 24a of the rotary member 24 is moved forward. The crest 24b comes into contact with the cam crest 2b of the fixed cam 2c of the front shaft member 2 to separate from the cam crest 4h of the rear cam 4g of the front member 4 and slide half the cam crest 2b of the fixed cam 2c so that the rotary member 24 rotates counterclockwise. It rotates to the state shown in FIG. 7(c).
Since the position of engagement of the cam crest 2b of the fixed cam 2c from the deep trough 2e to the shallow trough 2d is changed by the rotation of the rotating member 24, the tip member 4 reaches a position rearward from the initial position. Only returns. Further, since the core holding force of the slide member 6 is set to be stronger than the force of pulling the core 7 forward when the ball chuck 9 clamps the core 7, the slide member 6 advances with respect to the ball chuck 9 while holding the core 7. Therefore, the core 7 is pulled out forward from the ball chuck by the slide member 6, but the cam crest 24b of the rotating member 24 abuts on the shallow valley 2d of the fixed cam 4h, so that the ball chuck 9, the fastener 11, and the connector 13 are formed. The forward movement of the sliding cylinder 14, the front cylindrical body 18, and the rear cylindrical body 26 is stopped midway, so that the core 7 is not extended forward from the slide member 6.

Next, when a second writing pressure is applied to the core to write again from the state of FIG. 8, the ball chuck 9, the fastener 11, the connector 13, the sliding cylinder 14, the front cylindrical body 18, which receives the writing pressure, Although the rear cylinder 26 is stopped, the writing pressure exceeds the elastic force of the writing pressure receiving spring 28, so that the shaft cylinder 8 held by hand with respect to the front member 4 advances. Here, when the protruding portion 19b of the key member 19 contacts the slit portion 18c of the front tubular body 18, the forward movement of the tip member 4 is restricted and stopped. After that, the shaft cylinder 8 further advances, and the collar portion 19a of the key member 19 comes into contact with the rear end portion of the lateral hole portion 2a of the front shaft member 2 that has moved forward, or the rear portion of the front member 4 is inside the front shaft member 2. When it comes into contact with the step, the forward movement of the barrel 8 is restricted and stopped. At this time, since the slide member 6 holds the lead 7 by the lead holder 23, the slide member 6 does not move, but the front spring 22 is compressed and biased forward by an amount corresponding to the advance of the tip member 4. It becomes a state.
Further, when the shaft cylinder 8 moves forward from the state of FIG. 7C, the fixed cam 2c formed on the inner surface of the front shaft member 2 advances and is fixed to the cam crest 24b of the front cam 24a of the rotating member 24. When the abutment of the cam 2c with the shallow valley 2d of the cam mountain is released, the front cam 24a is elastically bulged forward. Therefore, the cam mountain 24b of the front cam 24a corresponds to the rear cam 4g of the front member 4. The cam member 4h slides halfway and the rotary member rotates counterclockwise to the state shown in FIG. 7(d).
In this operation, since the cam crest 24b of the rotating member 24 starts from the state of engaging with the shallow valley 2d of the fixed cam 2c, the tip member 4 is originally in the state of moving forward, and the writing pressure is applied to the core 7. When this happens, the amount of movement of the tip member 4 that advances is reduced.

Here, when the writing is stopped and the writing pressure on the core 7 is released to separate the core 7 from the paper surface, the ball chuck 9, which is elastically bulged forward by the elastic force of the writing pressure receiving spring 28, moves toward the barrel 8. The fastener 11, the connector 13, the sliding cylinder 14, the front cylinder 18 and the rear cylinder 26 move forward. Then, the front member 4 also advances as the front tubular body 18 advances. At this time, when the front member 4 moves forward, the rotating member 24 elastically pushed forward by the rear spring 27 also moves forward, but the cam crest 24b of the front cam 24a of the rotating member 24 is fixed to the front shaft member 2. By abutting on the cam crest 2b of the cam 2c, the tip member 4 is separated from the cam crest 4h of the rear cam 4g, and the cam crest 2b of the fixed cam 2c is half-slipped, and the rotary member 24 rotates counterclockwise to move the cam crest 2b of FIG. ) Return to the state of.
Further, since the cam crest 2b of the fixed cam 2c changes the position of engagement from the shallow valley 2d to the deep valley 2e due to the rotation of the rotating member 24, the tip member 4 returns to the position shown in FIG.
Further, since the core holding force of the slide member 6 is set to be stronger than the force of pulling the core 7 forward when the ball chuck 9 clamps the core 7, the slide member 6 advances with respect to the ball chuck 9 while holding the core 7. Therefore, the core 7 is pulled out forward from the ball chuck 9 by the slide member 6, and the cam crests 24b of the rotating member abut against the deep valleys 2e of the fixed cam 2c. , The connector 13, the sliding cylinder 14, the front cylinder 18, and the rear cylinder 26 further advance with respect to the front shaft member 2, and the core 7 held by the ball chuck 9 also advances.
As a result, the positional relationship among the respective components such as the shaft cylinder 8, the tip member 4, the rotating member 24, the ball chuck 9, the fastener 11, the connector 13, the sliding cylinder 14, the front cylinder body 18 is determined by the first writing pressure. Although the core 7 is pulled back to the front from the ball chuck 9 by the slide member 6, the core 7 is pushed forward from the tip hole portion of the slide member 6 by the slide member 6, as shown in FIG. The state becomes 10. Therefore, in this embodiment, the writing pressure is applied twice to the lead, so that the lead is once drawn forward.

In this embodiment, since the slide member can be moved back and forth with respect to the tip member 4, the protrusion 7f (sliding prevention portion) of the tip member 4 is gripped and the lead 7 is not pushed out by the writing pressure. Even in such a state, when the core is worn by writing and the slide member comes into contact with the paper surface, the slide member 6 retracts. Therefore, when writing is stopped and the writing pressure applied to the lead is released, the slide member advances while holding the lead 7, so that the lead 7 is pulled out from the ball chuck 9 and functions as a conventional automatic centering mechanical pencil. Configured.

As described above, by providing a protrusion (sliding prevention part) on the side surface of the tip member and operating the protrusion (slide prevention part) so that the tip member does not move back and forth, the lead is extended by applying and releasing the writing pressure. It was possible to obtain a mechanical pencil capable of easily switching between a state in which it is extended and a state in which it is not extended.

1... Mechanical pencil,
2... front shaft member, 2a... lateral hole, 2b... cam crest, 2c... fixed cam, 2d... shallow valley, 2e... deep valley,
3... rear shaft member, 3a... front inner stage,
4... front member, 4a... tip opening, 4b... inner step, 4c... rear inner hole, 4d... side hole,
4e... Outer side surface, 4f... Protrusion, 4g... Rear cam, 4h... Cam mountain,
5... Cap,
6... Slide member, 6a... Tip hole portion, 6b... Intermediate step portion,
7... wick,
8...shaft cylinder,
9... Ball chuck, 9a... Head, 9b... Recess, 9c... Step,
10... steel balls,
11... Fastener, 11a... Inclined part, 11b... Outer step part,
12... Chuck spring,
13... Connector, 13a... Intermediate part,
14... Sliding cylinder, 14a... Claw part,
15... Knock spring,
16... wick tank,
17... eraser,
18... Front cylinder, 18a... Window part, 18b... Step part, 18c... Slit part,
19... Key member, 19a... Collar part, 19b... Projection part,
20... Intermediate spring,
21... Stopper, 21a... Outer step part,
22... front spring,
23... Wick holder,
24... Rotating member, 24a... Front cam, 24b... Cam mountain,
25... washers
26... rear cylinder, 26a... outer step, 26b... inner step,
27... rear spring,
28... Writing pressure receiving spring.

Claims (3)

In the shaft cylinder, a lead feeding mechanism that allows the lead to move forward but prevents the lead from retracting, and a slide member that holds the lead with an appropriate force,
A mechanical pencil for feeding out the lead by applying and releasing writing pressure applied to the lead,
A rear portion of a tip member that encloses the slide member is disposed in the barrel.
The tip member is configured to be unrotatable and movable back and forth with respect to the barrel.
A rotary member provided with a front cam at the front is disposed behind the tip member,
The rotating member is configured to be rotatable and movable back and forth with respect to the barrel.
A rear cam that engages with a front cam of the rotating member, is provided at a rear portion of the front member,
A fixed cam that engages with the front cam of the rotating member is provided on the inner surface of the barrel;
A spring that elastically pushes the slide member forward is disposed between the slide member and the tip member,
On the side surface of the tip member or the barrel, a slide blocking portion that blocks the forward and backward movement of the tip member with respect to the barrel is provided.
By applying and releasing the writing pressure applied to the core, the front member moves back and forth with respect to the shaft cylinder, and the front cam of the rotating member engages with the rear cam of the front member and the fixed cam of the shaft cylinder. By doing so, the rotating member rotates and the core is fed out,
A mechanical pencil, characterized in that by operating the sliding prevention portion, the forward and backward movement of the tip member with respect to the barrel in applying and releasing the writing pressure applied to the core is prevented. The mechanical pencil according to claim 1, wherein the sliding prevention portion of the tip member is formed in a convex shape or a concave shape on an outer surface of the tip member or the barrel. The rear cam of the rear portion of the tip member and the fixed cam on the inner surface of the barrel are formed by saw blade-shaped cam ridges.
The rear cam of the front member and the fixed cam on the inner surface of the barrel are configured to move back and forth in a state of being out of phase with each other,
The cam mountain of the fixed cam of the shaft cylinder has a deep valley portion and a shallow valley portion,
The rotary member is rotated by applying and releasing the writing pressure applied to the core,
When the cam crest of the front cam of the rotating member engages with the deep trough of the fixed cam of the shaft cylinder, the tip member largely moves back and forth to extend the core,
The mechanical pencil according to claim 1 or 2, wherein when the cam crest of the front cam of the rotating member engages with the shallow trough of the fixed cam of the shaft cylinder, the lead is not extended. ..

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