JP2017193152A - mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical pencil capable of switching between a state in which a lead is protruded and a state in which the lead is not protruded by applying and releasing writing pressure.SOLUTION: A rear part of a tip member 4 containing a slide member 6 is disposed inside a shaft cylinder 8. The tip member 4 is configured to be non-rotatable and movable forward and backward with respect to the shaft cylinder 8. A rotary member 24 having a front cam 24a at a front part thereof is disposed behind the tip member 4. The rotary member 24 is configured to be rotatable and movable forward and backward with respect to the shaft cylinder 8. A rear cam 4 g engaging with the front cam 24a of the rotary member 24 is provided at a rear part of the tip member 4. A fixed cam 2c engaging with the front cam 24a of the rotary member 24 is provided on an inner face of the shaft cylinder 8. A front spring 22 for elastically urging the slide member 6 forward is disposed between the slide member 6 and the tip member 4. A slide block part for preventing forward and backward movement of the tip member 4 with respect to the shaft cylinder 8 is provided on a side face of the tip member 4 or the shaft cylinder 8.SELECTED DRAWING: Figure 2

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 lead is drawn out as the lead is worn during writing.

  Conventionally, Patent Document 1 is known as a mechanical pencil that is automatically drawn out by the amount of wear of the core, as previously filed by the applicant of the present application.

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

As a structure that solves this problem, Patent Document 2 is configured so that the tip of the sliding unit serving as the lead guide does not come into contact with the lead by extending the lead by applying and releasing the writing pressure applied to the lead at the time of writing. An automatic feed-out mechanical pencil is described.
As a structure of this Patent Document 2, in Example 3, a chuck unit for preventing the retraction of the core and a sliding unit for holding the core are arranged in the shaft cylinder, and the writing pressure is applied to the core at the time of writing. Since the sliding unit serving as the lead guide moves backward together with the lead when the contact is applied, the sliding unit does not come into contact with the writing surface and the writing feeling is not impaired. In this structure, a plurality of serrated cam peaks are formed in the rear end surface and the front member of the sliding unit, and a cylindrical member having a protrusion that engages with the serrated cam peaks is used to move the sliding unit back and forth. By rotating and moving back and forth by the cylinder and intermittently moving the cylindrical member back and forth, the core is drawn out once with a plurality of writing pressures, and the lead is prevented from being drawn out more than necessary. it can. Furthermore, in the case of this structure, the number of forward / backward movements of the sliding unit will be extended once depending on the use of the mechanical pencil, the hardness of the writing core, the paper quality, the wear of the core due to the writing language, etc. It can be set.
However, in the structure of Patent Document 2, the lead is drawn out once, depending on how many times the sliding unit is moved back and forth, depending on the usage of the mechanical pencil, the hardness and paper quality of the writing core, and the wear of the core due to the writing language. Although it can be manufactured by setting it, it can not cope with changes in the situation after use, so if you use it differently from the setting, the lead will protrude too much from the tip of the sliding unit at the time of writing and the lead will break. May occur.

Japanese Utility Model Publication No. 60-21273 International Publication WO2012 / 014832

  The present invention has been invented 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 the lead is extended and a state in which the lead is not extended by applying and releasing the writing pressure. .

The present invention
“1. In the shaft cylinder, a lead feeding mechanism that allows the lead to advance but prevents retraction, and a slide member that holds the lead with an appropriate force,
A mechanical pencil that extends the lead by adding and releasing the writing pressure applied to the lead,
In the shaft tube, a rear portion of the tip member including the slide member is disposed,
The tip member is configured to be unrotatable and movable back and forth with respect to the shaft tube,
A rotating member provided with a front cam at the front part is disposed behind the tip member,
The rotating member is configured to be rotatable and movable back and forth with respect to the shaft tube,
A rear cam that engages with a front cam of the rotating member at a rear portion of the tip member;
A fixed cam that engages with the front cam of the rotating member is provided on the inner surface of the shaft cylinder,
A spring that repels the slide member forward is disposed between the slide member and the tip member;
On the side surface of the tip member or the shaft tube, there is provided a sliding prevention portion that prevents the tip member from moving back and forth with respect to the shaft tube.
By applying and releasing the writing pressure applied to the core, the tip member moves back and forth with respect to the shaft tube, and the front cam of the rotating member, the rear cam of the tip member, and the fixed cam of the shaft tube are engaged. The rotating member is rotated and the core is drawn out,
A mechanical pencil characterized in that, by operating the sliding prevention portion, the tip member is prevented from moving back and forth with respect to the shaft cylinder in the application and release of the writing pressure applied to the core.
2. 2. The mechanical pencil according to item 1, wherein the sliding preventing 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 shaft tube.
3. The rear cam of the rear part of the tip member and the fixed cam on the inner surface of the shaft tube are formed by saw blade-shaped cam peaks,
The rear cam of the tip member and the rear cam of the inner surface of the shaft cylinder are configured to move back and forth with a half phase shift,
The cam crest of the fixed cam of the shaft tube includes a deep trough and a shallow trough,
The rotating member rotates by adding and releasing the writing pressure applied to the core,
When the cam crest of the front cam of the rotating member is engaged with a deep valley portion of the fixed cam of the shaft tube, the tip member moves back and forth greatly, and the core is extended.
3. The sharp according to claim 1 or 2, wherein the core is not extended when the cam crest of the front cam of the rotating member is engaged with a shallow valley portion of the rear cam of the front member. Pencil. Is.

The mechanical pencil of the present invention can be used as an ordinary mechanical pencil because writing is performed with the sliding prevention portion operated, since the leading and trailing movements of the tip member are prevented and the lead is not drawn out by the writing pressure. Further, when the lead is shortened, the lead is automatically drawn out by the pen 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 lead is worn during writing and the slider comes back in contact with the paper surface, Similarly, when the pen pressure is released and the slider moves forward, the lead can be automatically extended.

Further, the operation of the sliding prevention unit includes operations of gripping, pushing, sliding, and rotating the sliding prevention unit by hand, and the tip of the shaft cylinder is operated by operating the sliding prevention unit. It is sufficient that the sliding of the member becomes impossible. At this time, the sliding prevention portion may be formed on the outer surface of the tip member, or may be formed on the outer surface of the shaft tube.
In the case where 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 surface so as to be easily gripped so as not to slip. Further, if the sliding prevention portion is easy to grip, it does not matter if it has a convex shape or a concave shape.
Further, the sliding prevention part may be a switch shape formed so as to be slidable inwardly of the shaft cylinder, and the tip member is fixed by pushing the sliding prevention part to lock the shaft cylinder and the tip member. You may comprise so that it cannot slide.

  In the present invention, a shallow trough and a deep trough are formed on the cam crest of the fixed cam of the shaft cylinder, and the composition ratio between the shallow trough and the deep trough is changed, thereby adding and releasing the pen pressure applied to the core. It is possible to change the rate at which the lead is paid out. For example, when the lead is drawn out once by applying the writing pressure twice, the shallow valleys and the deep valleys may be alternately formed, and the lead is drawn out at a rate of once every 10 times. Then, after forming the shallow valleys continuously at nine places, it suffices to form one deep valley.

  In the present invention, a mechanical pencil that can easily switch between a state in which the lead is extended and a state in which the lead is not extended by applying and releasing the writing pressure is obtained by providing a sliding prevention portion on the side surface of the tip member or the shaft tube. 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 a present Example. It is sectional drawing to which the principal part of the present Example was expanded. It is sectional drawing in the AA of FIG. FIG. 4 is an enlarged schematic side view showing a relationship among a front cam of a rotating member, a fixed cam of a shaft cylinder, and a rear cam of a tip member in FIG. 3. It is a longitudinal cross-sectional view of the mechanical pencil of a present Example. FIG. 7A is a schematic side view showing a relationship among a front cam of a rotating member of a mechanical pencil, a fixed cam of a shaft cylinder, and a rear cam of a tip member of the present embodiment. FIG. ) Is a schematic side view showing the relationship between the cams in FIG. 6, FIG. 7 (c) in FIG. 8, and FIG. 7 (d) in FIG. It is a longitudinal cross-sectional view of the mechanical pencil of a present Example. It is a longitudinal cross-sectional view of the mechanical pencil of a present Example. It is a longitudinal cross-sectional view of the mechanical pencil of a present Example.

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 following mechanical pencil.
In this embodiment, the side with the writing tip is expressed as the front, and the opposite side is expressed as the rear. Moreover, the side close to the axial center of the shaft cylinder is expressed as inward, and the opposite side is expressed as outward.

1 is a side view of the mechanical pencil of the present embodiment, FIG. 2 is a longitudinal sectional view of the mechanical pencil of FIG. 1, FIG. 3 is an enlarged longitudinal sectional view of a main part, and FIG. It is sectional drawing in the AA of 3. As shown in FIGS. 1 and 2, the mechanical pencil 1 includes a front shaft member 2 formed in a cylindrical shape, a rear shaft member 3 screwed into a rear portion of the front shaft member 2, and a front of the front shaft member 2. A tip member 4 inserted from the opening and a cap 5 attached to the rear portion of the rear shaft member 3 are provided. In addition, a tip opening 4 a into which the slide member 6 can be inserted is formed at the tip of the tip member 4. Further, a tip hole portion 6 a into which the core 7 can be inserted is formed at the tip of the slide member 6.
In this embodiment, the front shaft member 2 and the rear shaft member 3 constitute a shaft cylinder 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 tube 8, and a hemispherical recess 9b is formed on the outer surface of the head portion 9a. Is formed. A spherical steel ball 10 is inserted into the concave portion 9 b of the ball chuck, and a cylindrical fastener 11 is provided so as to surround the steel ball 10 and the ball chuck 9.
In addition, an inclined portion 11 a that expands forward is formed on the inner surface of the front portion of the fastener 11, and the inclined portion 11 a is disposed so that the steel ball 10 inserted into the concave portion 9 b of the ball chuck 9 abuts on the inclined portion 11 a. It is.
Further, a step portion 9 c is formed on the outer surface of the ball chuck 9. A chuck spring 12 is stretched between the step portion 9 c and the inner step formed on the inner surface of the fastener 11. It is repelled rearward 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. When the connector 13 moves forward, the rear end of the ball chuck 9 and the front end of the connector 13 contact each other. It is arranged to touch.

In addition, a sliding cylinder 14 is disposed at the intermediate portion 13 a 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 a sliding spring 14 is stretched between the rear portion of the sliding cylinder 14 and the rear stepped portion of the connector 13, thereby sliding the sliding cylinder 14. 14, the connector 13 is ejected rearward.
A cylindrical core tank 16 is press-fitted into the rear part of the connector 13, and an eraser 17 is detachably attached to the inner hole in the rear part of the core tank 16, and is located behind the rear inner hole of the rear shaft member 3. A cap 5 is detachably attached to the outer surface of the rear portion of the lead tank 16 protruding to the rear.

  Since the present embodiment employs a general ball chuck type lead feeding mechanism in which the steel ball 10 is sandwiched between the ball chuck 9 and the fastener 11 as described above, the lead is held by the ball chuck 9. In this case, when the lead 7 is retracted, a wedge action is exerted and the lead 7 is strongly clamped. However, when the lead 7 is advanced, the wedge action is released so that it can be pulled out with a small force.

In addition, a cylindrical front cylinder 18 is disposed inside the shaft cylinder 8 and outside the fastener 11, and a window portion 18 a formed on the rear side surface of the front cylinder 18 and the sliding cylinder 14. The front cylinder 18 and the sliding cylinder 14 are integrally fixed by locking the claw portion 14a formed so as to protrude outward from the outer surface of the cylinder.
A step 18b is formed in the front inner hole of the front cylinder 18, and when the fastener 11 moves forward, the outer step 11b formed on the outer surface of the fastener 11 and the step of the front cylinder 18 are formed. The forward movement of the fastener 11 is regulated by being configured so as to come into contact with 18b. In addition, a slit portion 18c that penetrates the inside and outside and extends in the axial direction is formed on the side surface of the front cylinder 18.

As shown in FIGS. 2, 3, and 4, a front cylinder 18 is inserted in the rear inner hole 4 c of the tip member 4 inserted from the front opening of the front shaft member 2 so as to be movable back and forth. Further, two side holes 4d penetrating the inside and outside are formed on the side surface of the tip member 4 diagonally across the axis. A key member 19 formed in a nail shape and having a flange portion 19a is press-fitted and fixed to the side hole 4d, and the tip of the key member 19 protrudes inward from the inner surface of the tip member. By inserting the portion 19 b into the slit portion 18 c of the front cylinder 18, the front cylinder 18 can be moved back and forth with respect to the tip member 4 and cannot be rotated.
Further, the flange 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 a lateral hole portion 2a formed by extending the flange portion 19a in the axial direction on the side surface of the front shaft member. By arranging, the front member 4 can be moved back and forth with respect to the front shaft member 2 and cannot be rotated.
Thereby, the front cylinder 18 can move back and forth with respect to the tip member 4 only by a gap between the protrusion 19b of the key member 19 and the protrusion 19b in the front-rear direction within the slit 18c of the front cylinder 18. 4 is configured such 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 horizontal hole portion 2a of the front shaft member 2.

  Further, an intermediate spring 20 is stretched between the inner stage 4 b of the front member 4 and the front end of the front cylinder 18, and the front member 4 is repelled forward with respect to the front cylinder 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. It is.
A front spring 22 is stretched between the intermediate step portion 6 b of the slide member 6 and the outer step portion 21 a of the stopper 21, and the slide member 6 is repelled forward with respect to the tip member 4.

Further, as shown in FIG. 1, the outer surface 4 e of the tip member 4 is formed with a protruding portion 4 f (sliding prevention portion) that protrudes outward in a state of being arranged in the axial direction. The plurality of protrusions 4f are formed so as to be gradually higher toward the front, so that when the fingers are gripped by a hand, the fingers are caught and are not easily slipped, and are easy to operate.
In this embodiment, the protrusion 4f is molded on the outer surface of the tip member 4 using two-color molding, and an elastic synthetic resin such as an elastomer or a synthetic rubber such as silicon rubber is adopted as a material. Thus, it is formed to be more difficult to slip.

  As shown in FIGS. 2, 3, and 5, a rear cam 4 g formed in a saw blade shape toward the rear is formed at the rear end portion of the front member 4, and the rear cam 4 g is formed in a circumferential shape. A plurality of cam hills 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. As the synthetic rubber constituting the core holder 23, silicon rubber, nitrile rubber, or the like can be used. In this embodiment, the synthetic rubber is molded from 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 core 7 is held by the ball chuck 9 and weaker than the force of pushing the core rearward.

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

A rotating member 24 formed in a cylindrical shape is disposed behind the front member 4 and outside the front cylinder 18, and the rotation member 24 is rotatable with respect to the front cylinder 18 and the front shaft member 2. Is formed. Further, a front cam 24a having a width capable of simultaneously contacting both the fixed cam 2c of the front shaft member 2 and the rear cam 4g of the front member 4 is formed in a saw blade shape toward the front at the front end of the rotating member 24. The front cam 24a of the rotating member 24 is formed at a pitch interval that is double the pitch of the rear cam 2g of the front shaft member 2 and the rear cam 4g of the front member 4, and a deep valley of the fixed cam 2c of the front shaft member It is composed of the same number of cam peaks 24b as the portion 2e.
In the present invention, twelve deep valleys 2e are formed and twelve shallow valleys 2d are formed. Therefore, the cam crest 24b of the rotating member 24 is formed in the same number twelve as the deep valleys 2e. .

  A washer 25 is disposed behind the rotating cam 24, and the front end of the washer 25 is configured to abut the rear end of the rotating member 24. Further, the washer 25 is formed such that the tip sectional shape of the washer 25 is formed in an arc shape so that the contact area with the rotating member 24 is reduced, and the washer 25 is difficult to rotate when the rotating member 24 rotates.

A rear cylindrical body 26 formed in a cylindrical shape is disposed behind the front cylindrical body 18, and the front end inner peripheral portion of the rear cylindrical body 26 is press-fitted and fixed to the rear outer peripheral portion of the front cylindrical body 18. The front cylinder 18 and the rear cylinder 26 are fixed integrally.
In addition, the rear spring 27 is stretched between the outer step portion 26 a of the rear cylinder 26 and the rear end of the washer 25, so that the washer 25 and the rotating member 24 are repelled forward with respect to the rear cylinder 26. is there. Since the rotating member 24 is springed 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, a pen pressure receiving spring 28 is stretched between the inner step portion 26 b of the rear cylinder 26 and the front inner step 3 a of the rear shaft member 3, so that the rear cylinder 26 is elastically moved forward with respect to the shaft cylinder 8. It has been issued.

Next, using FIG. 3, FIG. 5, FIG. 6, FIG. 7, FIG. 8, and FIG. 9, the core 7 protruding from the tip hole portion 6a of the slide member 6 by writing with the jarp pencil 1 in the state of FIG. A state where the lead 7 is extended by the load and release of the writing pressure applied to the lead 7 when worn will be described.
When the mechanical pencil 1 of the present invention grips the shaft tube 8 in the state of FIG. 3 and further grips the protrusion 4f (sliding prevention portion) of the tip member 4 at the same time to write, the tip member is simultaneously pressed with the writing pressure. Since the pushing force to the front side works, the projection 4f (sliding prevention portion) is operated, and the tip member 4 can be restrained from moving back and forth with respect to the shaft tube 8, so that the slide member 6 is on the paper surface. As long as it is not touched, the lead 7 is not automatically drawn out even if written. For this reason, in a state where the protrusion 4f is gripped by hand, the core 7 protruding from the distal end hole 6a of the slide member 6 is gradually worn with writing.
When the core 7 is worn, the hand is released from the protruding portion 6f, and only the shaft cylinder 8 is held and the core 7 is pressed against the paper surface to perform the first writing. The connector 13, the sliding cylinder 14, the front cylinder 18, and the rear cylinder 26 are stopped, but are held by the hand together with the tip member 4 because the writing pressure exceeds the elasticity of the writing pressure receiving spring 28. The shaft cylinder 8 advances with respect to the front cylinder 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. When the part 19a comes into contact with the rear end part of the lateral hole part 2a of the front shaft member 2 that has advanced, 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 shaft cylinder 8 is restricted. Stop. At this time, since the slide member 6 holds the lead 7 with the lead holder 23, the slide member 6 does not move, but the forward spring 22 is compressed and urged forward by the amount of the advancement of the tip member 4. Become.
7A shows the positional relationship of the front cam, the rear cam, and the fixed cam 2c in the state of FIG. 3, and the shaft cylinder 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 portion 2e of the fixed cam 2c is released, the front cam Since 24a is bulleted forward, the cam crest 24b of the front cam 24a slides halfway on the cam crest 4h of the rear cam 4g of the front member 4, and the rotating member rotates half-phase counterclockwise in FIG. It will be in the state of b).

Here, when the writing is stopped and the writing pressure on the lead 7 is released and the lead 7 is separated from the paper surface, the ball chuck 9 urged forward by the elastic force of the writing pressure receiving spring 28 against the shaft cylinder 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 cylinder 18 advances, the tip member 4 also advances to the state shown in FIG. At this time, when the tip member 4 moves forward from the state of FIG. 7B, the rotating member 24 that is springed forward by the rear spring 27 also moves forward, but the cam of the front cam 24 a of the rotating member 24. The crest 24b contacts the cam crest 2b of the fixed cam 2c of the front shaft member 2 to move away from the cam crest 4h of the rear cam 4g of the front member 4, and the cam crest 2b of the fixed cam 2c is half-slided to rotate counterclockwise. It rotates to the state of FIG.7 (c).
Since the cam crest 2b of the fixed cam 2c changes the position where the deep trough 2e is engaged with the shallow trough 2d due to the rotation of the rotating member 24, the leading member 4 is moved to a position behind the initial position. Only return. Further, the lead holding force of the slide member 6 is set to be stronger than the force with which the ball chuck 9 pulls the lead 7 forward when the ball chuck 9 holds the lead 7, and therefore the slide member 6 moves forward with respect to the ball chuck 9 while holding the lead 7. For this reason, the core 7 is pulled out from the ball chuck forward by the slide member 6, but the ball crest 9, the fastener 11, and the connector 13 are formed by the cam crest 24 b of the rotating member 24 coming into contact with the shallow trough 2 d of the fixed cam 4 h. Further, since the forward movement of the sliding cylinder 14, the front cylinder 18 and the rear cylinder 26 stops halfway, the core 7 is not drawn forward from the slide member 6.

Next, when a second writing pressure is applied to the core in order to write again from the state of FIG. 8, the ball chuck 9 receiving the writing pressure, the fastener 11, the connector 13, the sliding cylinder 14, the front cylinder 18, Although the rear cylinder 26 is stopped, the shaft cylinder 8 held by the hand with respect to the tip member 4 moves forward when the writing pressure exceeds the elastic force of the writing pressure receiving spring 28. Here, when the protruding portion 19b of the key member 19 contacts the slit portion 18c of the front cylinder 18, the forward movement of the tip member 4 is restricted and stopped. Thereafter, the shaft cylinder 8 further advances, and the flange portion 19a of the key member 19 abuts on the rear end portion of the lateral hole portion 2a of the front shaft member 2 that has advanced, or the rear portion of the front member 4 is the inner portion of the front shaft member 2. When contacting the step, the forward movement of the shaft tube 8 is restricted and stopped. At this time, the slide member 6 does not move because the lead 7 is held by the lead holder 23, but the front spring 22 is compressed and urged forward by the amount of advance of the tip member 4 in FIG. It becomes a state.
7C moves forward from the state of FIG. 7C, the fixed cam 2c formed on the inner surface of the front shaft member 2 moves forward, and is fixed to the cam crest 24b of the front cam 24a of the rotating member 24. When the contact of the cam 2c with the shallow valley portion 2d of the cam crest is released, the front cam 24a is ejected forward, so that the cam crest 24b of the front cam 24a is connected to the rear cam 4g of the front member 4. The cam member 4h slides half way and the rotating member rotates counterclockwise to the state shown in FIG.
In this operation, since the cam crest 24b of the rotating member 24 starts from a state where it is engaged with the shallow valley 2d of the fixed cam 2c, the tip member 4 is originally moved forward, and writing pressure is applied to the core 7. When this occurs, the amount of movement by which the tip member 4 moves forward becomes small.

Here, when the writing is stopped and the writing pressure on the lead 7 is released and the lead 7 is separated from the paper surface, the ball chuck 9 urged forward by the resilient force of the writing pressure receiving spring 28 with respect to the shaft cylinder 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 cylinder 18 advances, the tip member 4 also advances. At this time, when the front member 4 moves forward, the rotating member 24 that is springed forward by the rear spring 27 also moves forward, but the cam crest 24 b of the front cam 24 a of the rotating member 24 is fixed to the front shaft member 2. By contacting the cam crest 2b of the cam 2c, the cam 4c is separated from the cam crest 4h of the rear cam 4g of the front member 4, and the cam crest 2b of the fixed cam 2c is half-slided and the rotating member 24 rotates counterclockwise. ) State.
Further, since the cam crest 2b of the fixed cam 2c changes the position of engagement from the shallow trough 2d to the deep trough 2e due to the rotation of the rotating member 24, the tip member 4 returns to the position of FIG.
Further, the lead holding force of the slide member 6 is set to be stronger than the force with which the ball chuck 9 pulls the lead 7 forward when the ball chuck 9 holds the lead 7, so that the lead 7 moves forward with respect to the ball chuck 9. For this reason, the core 7 is drawn forward from the ball chuck 9 by the slide member 6, and the cam crest 24b of the rotating member abuts against the deep trough 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 between the 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, and the front cylinder 18 is the first writing pressure. Although the lead 7 is pulled forward from the ball chuck 9 by the slide member 6, the lead 7 is fed forward from the tip hole portion of the slide member 6. 10 states are obtained. For this reason, in this embodiment, by applying the writing pressure twice to the core, the first core is fed 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 drawn out by the writing pressure. Even in such a state, when the lead is worn by writing and the slide member comes into contact with the paper surface, the slide member 6 moves backward. 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. It is configured.

  As described above, the protrusion is provided on the side surface of the tip member (sliding prevention portion), and the lead is extended by applying and releasing the writing pressure by operating the protrusion portion (sliding prevention portion) so that the tip member does not move back and forth. It was possible to obtain a mechanical pencil that can be easily switched between a state where it is pulled out and a state where it is not extended.

1 ... mechanical pencil,
2 ... Front shaft member, 2a ... Horizontal hole part, 2b ... Cam mountain, 2c ... Fixed cam, 2d ... Shallow valley part, 2e ... Deep valley part,
3 ... rear shaft member, 3a ... front inner stage,
4 ... tip member, 4a ... tip opening, 4b ... inner stage, 4c ... rear inner hole, 4d ... side hole,
4e ... outer side surface, 4f ... projection, 4g ... rear cam, 4h ... cam crest,
5 ... Cap,
6 ... slide member, 6a ... tip hole, 6b ... intermediate step,
7 ... Core
8 ... Shaft tube,
9 ... ball chuck, 9a ... head, 9b ... concave, 9c ... step,
10 ... steel balls,
11 ... Fastener, 11a ... Inclined part, 11b ... Outer step part,
12 ... Chuck spring,
13 ... Connector, 13a ... Middle part,
14 ... sliding cylinder, 14a ... claw part,
15 ... Knock spring,
16 ... Core tank,
17 ... Eraser,
18 ... Front cylinder, 18a ... Window part, 18b ... Step part, 18c ... Slit part,
19 ... key member, 19a ... collar, 19b ... projection,
20 ... Intermediate spring,
21 ... Stopper, 21a ... Outer step,
22 ... Front spring,
23 ... Core holder,
24 ... Rotating member, 24a ... Front cam, 24b ... Cam pile,
25 ... washer,
26 ... Back cylinder, 26a ... Outer step, 26b ... Inner step,
27 ... Back spring,
28 ... A pen pressure spring.

Claims (3)

The shaft cylinder has a lead feeding mechanism that allows the lead to move forward but prevents the lead from moving backward, and a slide member that holds the lead with an appropriate force.
A mechanical pencil that extends the lead by adding and releasing the writing pressure applied to the lead,
In the shaft tube, a rear portion of the tip member including the slide member is disposed,
The tip member is configured to be unrotatable and movable back and forth with respect to the shaft tube,
A rotating member provided with a front cam at the front part is disposed behind the tip member,
The rotating member is configured to be rotatable and movable back and forth with respect to the shaft tube,
A rear cam that engages with a front cam of the rotating member at a rear portion of the tip member;
A fixed cam that engages with the front cam of the rotating member is provided on the inner surface of the shaft cylinder,
A spring that repels the slide member forward is disposed between the slide member and the tip member;
On the side surface of the tip member or the shaft tube, there is provided a sliding prevention portion that prevents the tip member from moving back and forth with respect to the shaft tube.
By applying and releasing the writing pressure applied to the core, the tip member moves back and forth with respect to the shaft tube, and the front cam of the rotating member, the rear cam of the tip member, and the fixed cam of the shaft tube are engaged. The rotating member is rotated and the core is drawn out,
A mechanical pencil characterized in that, by operating the sliding prevention portion, the tip member is prevented from moving back and forth with respect to the shaft cylinder in the application and release of the writing pressure applied to the core. 2. 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 shaft tube. The rear cam of the rear part of the tip member and the fixed cam on the inner surface of the shaft cylinder are formed by a saw blade-shaped cam crest,
The rear cam of the tip member and the rear cam of the inner surface of the shaft cylinder are configured to move back and forth with a half phase shift,
The cam crest of the fixed cam of the shaft tube includes a deep trough and a shallow trough,
The rotating member rotates by adding and releasing the writing pressure applied to the core,
When the cam crest of the front cam of the rotating member is engaged with a deep valley portion of the fixed cam of the shaft tube, the tip member moves back and forth greatly, and the core is extended.
3. The mechanical pencil according to claim 1, wherein when the cam crest of the front cam of the rotating member is engaged with a shallow valley portion of the rear cam of the tip member, the lead is not extended. .

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