JP5874166B2 - mechanical pencil - Google Patents

Description

The present invention relates to a mechanical pencil in which a chuck unit for preventing retraction of a lead is disposed in a shaft cylinder, and particularly to a mechanical pencil that can effectively use a short lead.

Conventionally, a core case is arranged in the shaft cylinder so as to be movable back and forth, and a chuck body for gripping and releasing the core is fixed to the front end of the core case, and the chuck body is closed at the front of the chuck body. There is known a mechanical pencil that surrounds a chuck ring to be expanded and feeds the lead by advancing the lead case. The lead held by the chuck body is advanced and fed out by the advance operation of the lead case, but the advancement of only the chuck ring is restricted at a certain point during the advance operation of the lead case. At this time, the front portion of the chuck body is detached from the chuck ring, and the chuck body is expanded by its own elastic restoring force. By this expanding operation, the lead is released from the chuck body. Next, when the forward movement of the lead case is released, the chuck body moves backward and is again closed by the chuck ring to grip the lead. However, since the front outer peripheral portion (contact portion with the chuck ring) of the chuck body is conical , the chuck body is slightly retracted while holding the core at this time.
The operation of retracting the core while the chuck body is closed is a core in which the writing core is shortened by use and detached from the chuck body and cannot be gripped (hereinafter, the core in this state is referred to as a remaining core) Then, a gap is generated between the cores that follow the remaining cores and are gripped by the chuck body (hereinafter referred to as the subsequent cores), causing a sense of discomfort in writing. In other words, the remaining core is lightly held by the core detent member fixed inside the tip member positioned in front of the shaft cylinder, and the remaining core is fed out while being pushed out by the subsequent core held by the chuck body. It is. However, as described above, since the trailing core is retracted while the chuck body is closed by the chuck ring, a gap is generated between the rear end of the remaining core and the front end of the subsequent core. When writing was performed in this state, the writing pressure was larger than the friction force between the remaining core and the core detent member, so that the remaining core was retracted by the gap, and the writing operation was very uncomfortable. Finally, in order to eliminate the sense of incongruity, there was a case where the remaining core was thrown away and waste was generated.

Therefore, in Patent Document 1, a gap generated between the remaining core and the subsequent core is eliminated by retracting the central shaft unit including the chuck body in the core feeding process.
More specifically, the core feeding mechanism is disposed in the middle shaft, the middle shaft unit is disposed in the main body, and the middle shaft unit is retracted and then moved forward in the body feeding process in the main body. A moving means is provided.

JP 2002-11992 A

In the configuration of the above-mentioned Patent Document 1, the middle shaft unit including the chuck body is retracted in the core feeding process, and the middle shaft unit moves forward even after the chuck body feeds the core and is closed by the chuck ring. It is possible to fill a gap formed between the remaining core and the subsequent core. By operating the central shaft unit in this way, a good writing feeling can be obtained even in the remaining core state, and the point that the core can be used without waste is very excellent.
However, when no remaining core is used for writing, that is, when the writing core is held by both the chuck body and the core detent member, the writing core retreats together with the center shaft unit in the core feeding process. Then, the forward / backward movement is repeated a number of times, such as moving forward with the chuck body, moving backward again in the closing process of the chuck body, and further moving forward again with the central shaft unit. As a result, the writing core will be rubbed many times by the inner surface of the tip member and the core detent member, the surface of the writing core will be scraped, and the scraped core dust will not only stain the paper surface. In some cases, the core becomes thin and contributes to broken cores.

  Accordingly, in view of the above problems, the present invention provides a mechanical pencil in which a chuck unit for preventing the retraction of the core is disposed in the shaft cylinder, and the chuck unit of the chuck unit is retracted in an expanded state during the process of extending the core. Then, the gist of the present invention is to provide a chuck unit moving means that moves forward while the chuck body is closed and the core is gripped.

The present invention relates to a mechanical pencil in which a chuck unit for preventing the retraction of a lead is arranged in a shaft cylinder, and retreats in a state in which the chuck body of the chuck unit is expanded in the process of extending the lead, and then the chuck Since the chuck unit moving means that moves forward with the body closed and gripping the core is provided, the core can be filled between the remaining core and the subsequent core without retreating with the chuck unit as shown in the prior art. it can. For this reason, a good writing feeling can be obtained even in the remaining core state, and the core moves back and forth many times even in the core feeding process when the remaining core is not used for writing, and the inner surface of the tip member or the core return prevention member As a result, it is possible to prevent breakage of the lead due to scraping of the surface of the lead and dirt on the paper surface.

The longitudinal cross-sectional view which shows the structure of 1st Example of this invention. 1 is a partially enlarged longitudinal sectional view showing the configuration of a first embodiment of the present invention. The operation | movement figure of 1st Example of this invention. The operation | movement figure of 1st Example of this invention. The operation | movement figure of 1st Example of this invention. The operation | movement figure of 1st Example of this invention. The partial expanded longitudinal cross-sectional view which shows the structure of 2nd Example of this invention. The partial expanded longitudinal cross-sectional view which shows the structure of 3rd Example of this invention. The longitudinal cross-sectional view which shows the structure of 4th Example of this invention. The partial expanded longitudinal cross-sectional view which shows the structure of 4th Example of this invention. The operation | movement figure of 4th Example of this invention. The operation | movement figure of 4th Example of this invention. The operation | movement figure of 4th Example of this invention. The operation | movement figure of 4th Example of this invention. The operation | movement figure of 4th Example of this invention. The operation | movement figure of 4th Example of this invention. The partial expanded longitudinal cross-sectional view which shows the structure of 5th Example of this invention. The detailed perspective view of the lock member of the 5th example of the present invention, and a knock member The operation | movement figure of 5th Example of this invention.

The basic structure of a mechanical pencil having a lead-out structure according to the present invention is as follows. A chuck unit that prevents the lead from retracting is disposed in the shaft cylinder. Further, in the lead feeding process, there is provided a chuck unit moving means that moves backward while the chuck body of the chuck unit is expanded, and then moves forward while the chuck body is closed and grips the lead.
The operation will be described. When the lead tank unit disposed behind the chuck unit is pushed forward to advance the lead (hereinafter referred to as rear end knock), the chuck body contained in the chuck unit expands to release the lead. At the same time, the chuck unit and the lead tank unit are locked together. Next, when the pressing of the lead tank unit is released, the lead tank unit and the chuck unit are retreated while being integrated, and in the retreating process, the lock is released and the chuck body of the chuck unit is closed to sandwich the lead, The chuck unit moves forward. This completes the lead feeding. By adopting this structure, the lead is not retracted during the lead feeding process, so that the lead can be prevented from rubbing many times against the inner surface of the tip member or lead return preventing member. It is possible to prevent breakage of the core and dirt on the paper surface due to scraping of the surface.

The mechanical pencil lead-out structure of the present invention will be described based on an embodiment. FIG. 1 is a longitudinal sectional view showing the configuration of the first embodiment of the present invention, and FIG. 2 is a partially enlarged longitudinal sectional view.
A front member 2 is fixed in front of the outer shaft cylinder 1. The tip member 2 has a core holding member 3 press-fitted inside, and a core protection tube 4 fixed to the tip. A chuck unit including a sliding body 5, a chuck ring 6, a chuck 7, a spring retainer 8, and a chuck spring 9 is slid in the front-rear direction inside the tip member 2 and behind the core holding member 3. Arranged freely. The chuck unit is urged forward by a sliding body spring 10 disposed behind the sliding body 5.
A lead tank unit including a lead tank 11, a joint 12, and a knock member 13 is disposed behind the slide body 5 so as to be slidable in the front-rear direction inside the outer shaft cylinder 1. Further, a knock spring 14 is disposed on the outer periphery of the core tank 11, and a retaining member 15 is disposed on the outer periphery of the knock member 13. An eraser 16 is inserted into the rear end of the knock member 13, and a knock cover 17 is detachably disposed at the rear end of the knock member 13 so as to cover the eraser 16. A small-diameter portion 1a is provided behind the outer shaft cylinder 1, and a clip 18 is fixed to the small-diameter portion 1a by externally press-fitting a cylindrical attachment portion 18a. The clip 18 may be formed integrally with the outer shaft cylinder 1 or the knock member 13, the knock cover 14, and the retaining member 17. The above is the configuration of the present embodiment. In the present embodiment, the sliding body 5 and the joint 12 are characterized.

Further, each member will be described in detail. The tip member 2 has a through hole 2a and step portions 2b, 2c, and 2d formed therein, an inner diameter portion 2e formed in front of the step portion 2c, and an inner diameter portion 2f formed between the step portions 2c and 2d. Has been. Further, a screw 2g is formed behind the tip member 2, and the screw 2g is screwed and fixed to a screw 1g formed in front of the outer shaft cylinder 1.
The core holding member 3 has a through hole 3a in the axial direction, the front has a flat cone at the front, the rear has a cylindrical shape, and a collar 3b at the rear. The core holding member 3 is press-fitted and fixed to the tip member 2 in a state where the flange 3b is brought into contact with the inner step 2b of the tip member 2 and positioned. The material used for the core holding member 5 may be an elastic resin, and specific examples thereof include nitrile butadiene rubber, silicone rubber, and fluorine rubber. Further, the core protection tube 4 press-fitted and fixed in the through hole 2a of the tip member 2 is arranged for the purpose of protecting the fed core and improving the visibility, but may be formed integrally with the tip member 2. . The material used for the core protection tube 4 is preferably a metal in order to protect the core (addition of a function for preventing core breakage). Specifically, iron and its alloy, copper and its alloy, etc. are mentioned.

As described above, the chuck unit includes the sliding body 5, the chuck ring 6, the chuck 7, the spring retainer 8, and the chuck spring 9. The sliding body 5 has a step portion 5a and an inclined protrusion 5b formed on the inner diameter portion, and step portions 5c, 5d, and 5e formed on the outer periphery. Further, the rear end of the chuck ring 6 is press-fitted and fixed to the step portion 5 a of the inner diameter portion of the sliding body 5. In this embodiment, the chuck ring 6 has a flange at the rear end. However, if the chuck ring 6 can be fixed to the sliding body 5 so as not to be detachable, the chuck ring 6 may have a shape without a flange or a shape with a reduced diameter. Alternatively, the sliding body 5 and the chuck ring 6 can be formed integrally. Moreover, it is good also as a structure which provides a slit in the rear part of the sliding body 5 in the position which opposes, and is easy to expand. That is, by adopting a structure that is easy to expand, it is possible to adjust the locking force caused by the fitting between the inclined protrusion 5b of the sliding body 5 and the groove 12c of the joint 12 during the rear end knocking operation described later. Become.
The chuck 7 to be inserted into the chuck ring 6 is slit into three at the front to form a slit 7a. Further, an arrowhead-like convex portion 7 b provided at the rear end of the chuck 7 is press-fitted and fixed to the inner diameter portion 8 a of the spring retainer 8. A chuck spring 9 is stretched between the front end of the spring retainer 8 and the rear end of the chuck ring 6 to urge the chuck 7 and the spring retainer 8 backward. The chuck 7 is urged rearward, and the tapered portion 7 c formed at the tip is pressed against the front inner diameter portion 6 a of the chuck ring 6, so that the tri-section portion of the chuck body 7 is closed and the core 19 is closed. Grip. In this embodiment, the chuck is divided into three parts, but it is also possible to process it into two parts.
The chuck unit is urged forward by a sliding body spring 10 stretched between a step portion 1 e of the outer shaft cylinder 1 and a step portion 5 e of the sliding body 5, and the step portion 5 c is a step of the tip member 2. Positioning is performed by contacting the portion 2d. Further, the front outer peripheral portion 5e of the sliding body 5 is formed to be slightly thinner than the inner diameter portion 2f of the tip member 2, and when the sliding body 5 slides back and forth inside the tip member 2 during the rear end knocking operation. Become a guide. These positioning and guide portions are not limited to the portions of the present embodiment, and for example, positioning at the front end of the sliding body 5 or forming the outer diameter of the chuck ring 6 slightly narrower than the inner diameter portion 2 e of the tip member 2. It is also possible to guide.

The chuck ring 6 constituting the chuck unit is made of a metal having excellent strength and durability because the front inner peripheral portion 6a receives its own elastic restoring force when the chuck 7 is closed, for example, Copper or an alloy thereof, iron or an alloy thereof, aluminum or an alloy thereof, zinc or an alloy thereof is preferable. In addition, since the material of the chuck 7 is repeatedly elastically deformed when it is expanded and closed, the above-described metal having excellent strength and durability is desirable, but relatively hard synthetic resins such as acrylonitrile, polycarbonate, polyacetal, etc. These synthetic resins may be filled with inorganic powder, glass fiber, carbon fiber or the like.

The core tank unit includes the core tank 11, the joint 12, and the knock member 13, as described above. A rear outer diameter portion 12 a of the joint 12 is press-fitted into the front inner diameter portion 11 a of the core tank 11. In this embodiment, the front inner diameter portion 11a of the core tank 11 and the rear outer diameter portion 12a of the joint 12 are provided with grooves and protrusions to prevent the core tank 11 and the joint 12 from being detached and fixed. The core tank 11 and the joint 12 may be formed integrally with each other by fixing with intermittent rib fitting or simple press fitting. Further, a groove 12c is provided on the outer periphery of the front side surface portion 12b of the joint 12, and the groove 12c is fitted to the inclined protrusion 5b of the sliding body 5 during a core feeding operation by a rear end knock described later. Here, the distance from the groove 12c to the tip of the joint 12 is designed to be slightly larger than the distance from the inclined protrusion 5b of the sliding body 5 of the chuck unit to the rear end of the spring retainer 8.
Further, a tip end portion 13a of the knock member 13 is fixed to the rear end of the lead tank 11 so as not to be detachable. The knock member 13 is provided with a step portion 13b, flange portions 13c and 13d, and a rear end enlarged diameter portion 13e. An eraser 16 is attached to the rear end enlarged diameter portion 13e, and a knock cover 17 is detachably attached to the flange portion 13d to cover the eraser 16.
Further, the core tank unit is urged rearward by a knock spring 14 stretched between the step portion 1 d of the outer shaft cylinder 1 and the step portion 13 b of the knock member 13. In addition, the core tank unit is positioned by the flange portion 13c of the knock member 13 coming into contact with the retaining member 15 that is press-fitted and fixed to the step portion 1b of the outer shaft cylinder 1. The shape of the retaining member 15 is not limited to a cylindrical shape, and it is possible to use a ring having a C-shaped cross section or a plurality of members, or after inserting the core tank unit, The rear end may be formed to be narrower than the flange 13c of the knock member 13 by caulking. That is, it is only necessary to prevent the lead tank unit from falling off the outer shaft cylinder 1. Further, when the rear end knocking operation is performed, the stepped portion 1c of the outer shaft cylinder 1 and the flange portion 13c of the knocking member 13 are in contact with each other, thereby preventing excessive pushing of the rear end knock.

Here, the order of each force of the urging force of each spring, the core holding force of the core holding member 3, and the locking force brought about by the fitting of the inclined protrusion 5b of the sliding body 5 and the groove 12c of the joint 12 is as follows. Detailed description. The following magnitude relationship is required in order from the weakest.
The core holding force of the core holding member 3 is weaker than the urging force of the sliding body spring 10, and the urging force of the sliding body spring 10 is more than the locking force brought about by the fitting of the inclined protrusion 5 b of the sliding body 5. weak. Further, the locking force is set to be weaker than the urging force of the knock spring 14.
The biasing force of the chuck spring 9 is not required to have a magnitude relationship with the other resilient members, but when the knock member 13 is pressed to extend the lead, a human finger can be moved through the lead tank 11 or the like. It is necessary to set the biasing force to such an extent that the chuck spring 9 can be contracted. However, a force that biases the chuck body rearward is necessary so that the core does not get lost during writing.

Next, the operation of the first embodiment of the present invention to advance the lead tank and feed the lead will be described. 3 to 6 are operation diagrams of the rear end knocking operation.

When the knock cover 17 is pressed to pull out the lead 19 (hereinafter referred to as rear end knock), the lead tank 11 moves forward against the resilience of the knock spring 14. As the lead tank 11 advances, the front side surface portion 12b of the joint 12 slides while climbing on the inclined protrusion 5b of the sliding body 5, and eventually the tip of the joint 12 comes into contact with the rear end of the spring retainer 8 (FIG. 3). . At this time, the chuck 7 is closed by the chuck ring 6 and the core 19 is gripped.

Further, when the pressing force to the knock cover 17 is increased, the spring presser 8 and the chuck 7 are advanced against the chuck spring 9 by the joint 12 (FIG. 4). For this reason, the taper portion 7c of the chuck 7 is disengaged from the front inner diameter portion 6a of the chuck ring 6, and the chuck 7 expands to release the core 19. At the same time, the groove 12c of the joint 12 and the inclined protrusion 5b of the sliding body 5 are fitted, and the core tank unit and the chuck unit are locked together. Further, at this time, the step portion 1b of the outer shaft cylinder 1 and the front end of the flange portion 13c of the knock member 13 come into contact with each other, and therefore the user cannot push the knock cover 17 excessively.

Next, when the pressing force to the knock cover 17 is released, the elastic force of the knock spring 14 and the locking force brought about by the fitting of the inclined projection 5b of the sliding body 5 and the groove 12c of the joint 12 cause the elasticity of the sliding body spring 10. Since the force is higher, the lead tank unit and the chuck unit are moved backward while resisting the biasing force of the sliding body spring 10 while being integrated. As shown in FIG. 5, when the step portion 5 d on the outer periphery of the sliding body 5 contacts the step portion 1 f of the outer shaft cylinder 1, the chuck unit is prevented from moving backward. During this time, since the chuck 7 remains expanded, the core 19 does not retract.

Even after the chuck unit is prevented from retreating, the lead tank unit continues to retreat due to the elastic force of the knock spring 14. In the process of the backward movement, the inclined protrusion 5b of the sliding body 5 is detached from the groove 12c of the joint 12. Then, the lead tank unit moves backward until the flange 13b of the knock member 13 contacts the retaining member 15 and returns to the original state.
On the other hand, since the pressing force by the joint 12 is removed, the chuck 7 is retracted by the elastic force of the chuck spring 9 and is closed by the chuck ring 6 to grip the core 19 again. Further, since the backward urging force received from the knock spring 14 via the joint 12 is eliminated, the sliding body 5 is advanced by the elastic force of the sliding body spring 10, and the step portion 5 c is the step portion of the tip member 2. It comes into contact with 2d and returns to its original position. That is, since the chuck 7 moves forward while holding the lead 19, the lead 19 also moves forward. As a result, the length of the lead 19 protruding from the tip of the lead protection tube 4 becomes L in FIG. 6. Extends the indicated length.
In the present embodiment, an example in which the writing core is held by both the chuck 7 and the core holding member 3 is shown. However, even when the remaining core is used for writing, the chuck 7 moves the subsequent core in the lead feeding process. It is fed out without gripping and retreating, and the remaining core is pushed out by this subsequent core. For this reason, there is no gap between the remaining core and the subsequent core, that is, the remaining core does not retreat when writing, and the remaining core can be used without waste.
In addition, since it is not necessary to cause the chuck 7 to largely protrude from the chuck ring 6 to be expanded, a space for the chuck 7 to advance is not required inside the tip member 2, and the chuck 7 can be disposed immediately after the core holding member 3. The remaining core itself can be shortened.
In this structure, it is possible to provide a cushioning action at the time of writing by arbitrarily setting the elastic force of the sliding body spring 10. That is, when an excessive writing pressure is applied so that the lead is broken during writing, the sliding body spring 10 is bent, so that the chuck unit for gripping the lead is retracted and the lead is immersed in the lead protection tube 4. , Can prevent breakage of the core.

FIG. 7 is a partially enlarged longitudinal sectional view showing the configuration of the second embodiment of the present invention. A front member 21 is fixed in front of the outer shaft cylinder 20. The tip member 21 has a core holding member 22 press-fitted inside and a core protection tube 23 fixed to the tip. Further, inside the front member 21 and behind the core holding member 22, a chuck unit including a sliding body 24, an inclined cylindrical body 25, a connecting member 26, a chuck 27, a ball 28, and a chuck spring 29 is provided. It is arranged to be slidable in the front-rear direction. The chuck unit is urged forward by a sliding body spring 30 disposed on the outer periphery of the sliding body 24. Further, inside the outer shaft cylinder 20 and behind the sliding body 24, a core tank unit composed of a core tank 31, a joint 32, and a knock member (not shown), as in the first embodiment, It is slidably arranged in the front-rear direction. The urging / positioning of the lead tank unit and other parts in the rear part are the same as in the first embodiment. The configuration of the present embodiment is as described above. However, in the present embodiment, the chuck unit that prevents the retraction of the core is a ball chuck mechanism that uses the inclined cylindrical body 25 and the ball 28, and is different from the first embodiment. Yes.

Further, each member will be described in detail. The tip member 21 has a through hole 21a and step portions 21b and 21c formed therein, and a screw 21d formed at the rear is screwed and fixed to a screw 20a formed at the front of the outer shaft cylinder 20. Yes. The core holding member 22 that is press-fitted and fixed to the step portion 21b of the tip member 21 has a through hole 22a in the axial direction, has a flat tip at the front, and a cylindrical shape at the rear. The core holding member 22 is shaped into a shape having a ridge at the rear as in the first embodiment, and a step portion is provided in the tip member 21, and the lead holding member 22 is provided in the tip member 21. 22 may be positioned.

As described above, the chuck unit includes the sliding body 24, the inclined cylinder 25, the connecting member 26, the chuck 27, the ball 28, and the chuck spring 29.
The sliding body 24 has a small diameter portion 24a and a flange portion 24b formed on the outer periphery, and a step portion 24c and an inclined protrusion 24d formed therein. On the inner surface of the inclined cylindrical body 25, an inclined surface 25a having a diameter increasing toward the front is formed. The inclined cylindrical body 25 is fixed to the inside of the connecting member 26 so as not to be detachable, and the rear end of the connecting member 26 is press-fitted into the small diameter portion 24 a of the sliding body 24. A pair of chucks 27 are arranged inside the inclined cylindrical body 25 so as to be able to move back and forth. A hemispherical concave portion 27a is formed on the outer peripheral surface in front of the chuck 27, a core gripping portion 27b is formed on the inner surface, and a collar portion 27c is formed on the rear portion. A spherical ball 28 is interposed between the concave portion 27 a and the inclined surface 25 a of the inclined cylindrical body 25. Further, a chuck spring 29 is stretched between the step portion 24 c of the sliding body 24 and the flange portion 27 c of the chuck 27. The chuck 27 is urged rearward by the chuck spring 29 so that the chuck 27 is acted in the closing direction via the ball 28 in contact with the inclined surface 25a of the inclined cylinder 25, and the core 34 is gripped. . That is, a ball chuck mechanism that allows the lead to advance but prevents its retreat by a wedge action.

The inclined cylindrical body 25 and the chuck 27 constituting the chuck unit are made of a metal having excellent strength and durability, for example, copper, an alloy thereof, iron, or the like because the ball 28 is in contact with the inclined surface 25a or the recessed portion 27a. Alloys, aluminum and alloys thereof, zinc and alloys thereof are desirable, but relatively hard synthetic resins such as acrylonitrile, polycarbonate, polyacetal, etc., and these synthetic resins are filled with inorganic powder, glass fiber, carbon fiber, etc. It may be what you did. Further, the sliding body 24 and the inclined cylinder body 25 are connected via the connecting member 26. However, the sliding body 24 and the inclined cylinder body 25 may be directly fixed in a non-detachable manner, or may be integrally formed. Is possible.

The chuck unit is biased forward by a slide body spring 30 disposed between the step portion 20b of the outer shaft cylinder 20 and the flange portion 24b of the slide body 24, and the step portion 26a of the connecting member 26 is a leading member. Positioning is performed by contacting the stepped portion 21c. Here, the contact portion for positioning is not limited to the stepped portion 26a of the connecting member 26. For example, the front end of the connecting member 26 and the flange portion 24b of the sliding body 24 and the stepped portion and the rear end of the tip member 21 are in contact with each other. The chuck unit may be positioned by contact.
As described above, the lead tank unit includes the lead tank 31, the joint 32, and a knock member (not shown). A rear outer diameter portion 32 a of the joint 32 is press-fitted into the tip of the tank 31. On the outer periphery of the joint 32, grooves 32b and 32c are provided in order from the front. In normal times, the inclined protrusion 24d of the sliding body 24 is engaged with the groove 32b, and the groove 32c engages with the inclined protrusion 24d of the sliding body 24 during the core feeding operation by the rear end knock. The joint 32 may have the same shape as that of the first embodiment. A lead guide pipe 33 is inserted into the step portion 32 d of the joint 32, and has a role of making it easy to insert the lead stored in the lead tank 31 into the chuck 27. A knock member is fixed to the rear end of the lead tank 31 so as not to be detachable. However, the configuration and arrangement of the other members including the knock member are the same as those in the first embodiment, and detailed description thereof is omitted. To do. The relationship between the forces of the springs and the like is the same as in the first embodiment.
As described above, in the ball chuck mechanism using the inclined cylindrical body 25 and the ball 28, the urging force of the chuck spring 29 can be reduced because the core is gripped by the wedge effect. For this reason, the clamping force applied to the lead from the chuck 27 during storage is smaller than that of the first embodiment, and the lead is prevented from being damaged. Further, at the time of assembly, in the configuration of the first embodiment, after the chuck 7 is inserted into the chuck ring 6 and the chuck spring 9, the tip of the chuck 7 is brought into contact with the non-moving surface and the spring retainer 8 is press-fitted and fixed. There is a risk of bending. However, in the configuration of the present embodiment, the chuck 28 can be bent so that the tip of the chuck 27 protrudes from the inclined cylinder 25 and the ball 28 can be assembled. Therefore, the chuck 27 can be assembled without applying a load. it can.

Next, the rear end knocking operation in the second embodiment of the present invention will be described. When a knock cover (not shown) is pressed to feed the lead, the lead tank 31 moves forward. As a result, the joint 32 comes into contact with the rear end of the chuck 27, and the chuck spring 29 cannot be resisted and the chuck 27 moves forward. As the chuck 27 moves forward, gaps are formed between the recess 27a of the chuck 27 and the ball 28, and between the ball 28 and the inclined surface 25a of the inclined cylinder 25, and the wedge effect of the ball chuck mechanism acts. The chuck 27 expands. At the same time, the groove 32c of the joint and the inclined protrusion 24d of the sliding body 24 are fitted, and the core tank unit and the chuck unit are locked together.
Next, when the pressing force to the knock cover is released, the lead tank unit and the chuck unit are moved backward by the urging force of the knock spring while being integrated. When the rear end of the sliding body 24 comes into contact with the step portion 20b of the outer shaft cylinder 20, the chuck unit is prevented from moving backward. During this time, since the chuck 27 remains expanded, the core 34 does not retract.
Further, even after the chuck unit is prevented from retreating, the lead tank unit continues to retreat due to the urging force of the knock spring, so that the inclined protrusion 24d of the sliding body 24 is removed from the groove 32c of the joint 32, and the lead tank unit is returned to the original position. Return to the position.
On the other hand, since the pressing force by the joint 32 is released, the chuck 27 is retracted by the elastic force of the chuck spring 29, and the chuck unit (chuck 27) again exhibits a wedge action and grips the core 34. Further, the chuck unit is advanced by the urging force of the sliding body spring 30, the stepped portion 26 a of the connecting member 26 comes into contact with the stepped portion 21 c of the tip member 21, and returns to the original position. That is, since the chuck 27 moves forward with the core 34 held, the core 34 also moves forward. As a result, the length of the core 34 protruding from the tip of the core protection tube 23 becomes L in FIG. Extends the indicated length.
In the structure of the second embodiment as well, a cushioning action can be provided at the time of writing by arbitrarily setting the elastic force of the sliding body spring 30.

FIG. 8 is a partially enlarged longitudinal sectional view showing the configuration of the third embodiment of the present invention. A front member 36 is fixed in front of the outer shaft cylinder 35. Inside the tip member 36, a tip sliding body 37 is disposed so as to be movable back and forth. The tip sliding body 37 has a core holding member 38 press-fitted therein and a core protection tube 39 fixed to the tip. Behind the tip sliding body 37, a chuck unit of a ball chuck mechanism including a sliding body 40, an inclined cylinder 41, a connecting member 42, a chuck 43, a ball 44, and a chuck spring 45 is slidable in the front-rear direction. Is arranged. A tip spring 46 is stretched between the front surface of the connecting member 42 of the chuck unit and the rear end of the tip sliding body 37. The tip sliding body 37 is urged forward by the tip spring 46 and is positioned by the stepped portion 37a of the tip sliding member 37 coming into contact with the stepped portion 36a of the tip member. The chuck unit is biased forward by a sliding body spring 47. Further, a lead tank unit including a lead tank 48, a joint 49, and a knock member (not shown) is disposed behind the chuck unit. During the core feeding operation by the rear end knock, the groove 49a of the joint 49 is fitted to the inclined protrusion 40a provided on the inner surface of the sliding body 40.

Subsequently, the order of each force of the biasing force of each spring, the core holding force of the core holding member 38, and the locking force brought about by the fitting between the inclined protrusion 40a of the sliding body 40 and the groove 49a of the joint 49 will be described in detail. Describe. The following magnitude relationship is required in order from the weakest.
The biasing force of the chuck spring 45 is weaker than the biasing force of the tip spring 46, and the biasing force of the tip spring 46 is set to be weaker than the lead holding force of the lead holding member 38. The lead holding force of the lead holding member 38 is set to be weaker than the biasing force of the sliding body spring 47. Further, the biasing force of the sliding body spring 47 is weaker than the locking force caused by the fitting of the inclined protrusion 40a of the sliding body 40 and the groove 49a of the joint 49, and in addition, the locking force is applied to the knock spring. It is set to be weaker than the power.

Since the configuration and arrangement of other parts such as the chuck unit and the lead tank unit are the same as those in the second embodiment, detailed description thereof will be omitted. This embodiment differs from the first and second embodiments in that a tip sliding body 37 having a core holding member 38 fixed inside the tip member 36 is movably moved back and forth. is there. By adopting such a configuration, in addition to feeding the lead by the rear end knock, it becomes possible to automatically feed the lead during writing.

Next, the operation of extending the lead in the third embodiment of the present invention will be described. First, the lead-out operation by the rear end knock is the same as that in the second embodiment, and thus the description thereof is omitted. The operation different from that of the second embodiment by adopting the configuration of the present embodiment is that the lead is automatically extended during writing, and the details will be described below.
FIG. 8 is a view at the time when writing is started by taking out the lead by the rear end knock, but if the writing is continued, the lead 50 is worn, and the tip of the lead 50 becomes substantially the same position as the tip of the lead protection tube 39. . When the tip of the lead 50 is pressed against the paper surface in order to continue writing in this state, the lead protection tube 39 is also pressed against the paper surface, and the tip sliding body 37 resists the core gripping force of the lead holding member 38 and the biasing force of the tip spring 46. Then retreat. For this reason, the exposure amount of the core 50 protruding from the core protection tube 39 is slightly increased, and writing can be continued. Further, when the lead 50 is detached from the paper surface during writing, the tip sliding body 37 moves forward by the biasing force of the tip spring 46. At this time, the lead holding member 38 holds the lead 50 and the wedge action of the ball chuck mechanism is released, so that the lead 50 is allowed to advance. As a result, the lead 50 is pulled out of the chuck 43. . In this way, by repeatedly pressing the core 50 on the paper surface and releasing the pressing, the core 50 is automatically drawn out along with the writing and the writing can be continued.
In the configuration of the third embodiment as well, a cushioning action can be provided at the time of writing by arbitrarily setting the resilient force of the sliding body spring 47.

FIG. 9 is a longitudinal sectional view showing the configuration of the fourth embodiment of the present invention, and FIG. 10 is a partially enlarged longitudinal sectional view. A front member 52 is fixed in front of the outer shaft cylinder 51. Inside the tip member 52, a tip sliding body 53 is disposed so as to be movable back and forth. The tip sliding body 53 has a core holding member 54 press-fitted and fixed inside, and a core protection tube 55 fixed to the tip. The tip sliding body 53 is urged rearward by a tip spring 56. Further, an inclined plate 57 is disposed inside the tip member 52 and behind the tip sliding body 53, and a positioning ring 58 is press-fitted and fixed behind the inclined plate 57. Behind the positioning ring 58, a chuck unit of a ball chuck mechanism including a sliding body 59, an inclined cylindrical body 60, a connecting member 61, a chuck 62, a ball 63, and a chuck spring 64 is slidably disposed in the front-rear direction. At the same time, it is urged forward by the sliding body spring 65.
A core tank unit including a core tank 66, a joint 67, and a knock member 68 is slidably disposed in the front-rear direction inside the outer shaft cylinder 51 and behind the chuck unit. A core guide pipe 69 is inserted at the tip of the joint 67. Further, a knock spring 70 is disposed on the outer periphery in front of the flange portion 66a of the core tank 66, and a retaining member 71 is disposed on the outer periphery behind the flange portion 66a. An eraser 72 is inserted into the rear end of the knock member 68, and a knock cover 73 is detachably disposed at the rear end of the knock member 68 so as to cover the eraser 72.
Further, a small diameter portion 51 a is provided behind the outer shaft cylinder 51, and a cylindrical mounting portion 74 a of the clip 74 is fitted into the small diameter portion 51 a so that the clip 74 is fixed to the outer shaft cylinder 51. Has been. The clip 74 can be formed integrally with the outer shaft cylinder 51 or the knock member 68, the retaining member 71, and the knock cover 73. The above is the configuration of the present embodiment, but the present embodiment is different from the first to third embodiments in that the inclined plate 57 is disposed inside the tip member 52.

Further, each member will be described in detail. The tip member 52 has a through hole 52a, step portions 52b and 52c, an inclined hole 52d, a fulcrum 52e, and an intermittent rib 52f formed therein. Further, a screw 52g is formed behind the tip member 52, and the screw 52g is screwed and fixed to a screw 51b formed in front of the outer shaft cylinder 51.
A tip sliding body 53 is disposed in the tip member 52 so as to be movable back and forth. The tip sliding body 53 has a through hole 53a and a stepped portion 53b inside, and a stepped portion 53c and a rear outer diameter portion 53d formed outside. The core holding member 54 press-fitted and fixed to the stepped portion 53b of the tip sliding body 53 has a through hole 54a in the axial direction, the front is a flat cone and the rear is cylindrical. Further, the core protection tube 55 is press-fitted and fixed in the through hole 53 a of the tip sliding body 53. The core protection tube 55 is disposed for the purpose of protecting the fed core and improving the visibility, but it may be formed integrally with the tip sliding body 53. The core protection tube 55 is formed to be slightly thinner than the through hole 55a of the tip member 52, and serves as a guide when the sliding body 53 slides back and forth inside the tip member 52. In addition, an intermittent rib 52f is provided inside the tip member 52, and the distal end sliding body 53 is also formed by making the inner diameter of the intermittent rib 52f slightly larger than the rear outer diameter portion 53d of the distal end sliding body 53. A guide action is generated when the inside of the tip member 52 slides back and forth. The intermittent rib 52f may be an all-round rib. The tip sliding body 53 is urged rearward by a tip spring 56 stretched between the step portion 53 c and the step portion 52 b of the tip member 52.
Further, an inclined plate 57 is disposed inside the tip member 52 and behind the tip sliding body 53. The outer diameter of the inclined plate 57 is smaller than that of the inclined hole 52d of the tip member 52, and the outer peripheral portion 57a is formed in a smooth arc shape. The inclined plate 57 is swingable with the fulcrum 52e of the tip member 52 as a fulcrum. A positioning ring 58 is press-fitted and fixed to the stepped portion 52c of the tip member 52 so as not to be attached or detached.

As described above, the chuck unit includes the slide body 59, the inclined cylinder body 60, the connecting member 61, the chuck 62, the ball 63, and the chuck spring 64. The sliding body 59 has a small-diameter portion 59a and a flange portion 59b on the outer periphery, and a step portion 59c and an inclined protrusion 59d inside. On the inner surface of the inclined cylindrical body 60, an inclined surface 60a whose diameter increases toward the front is formed. The inclined cylindrical body 60 is fixed to the inside of the connecting member 61 so as not to be detachable, and the rear end of the connecting member 61 is press-fitted into the small diameter portion 59 a of the sliding body 59. A pair of chucks 62 are arranged inside the inclined cylindrical body 60 so as to be able to move back and forth. A hemispherical concave portion 62a is formed on the outer peripheral surface in front of the chuck 62, a core gripping portion 62b is formed on the inner surface, and a flange portion 62c is formed on the rear portion. A spherical ball 63 is interposed between the recess 62 a and the inclined surface 60 a of the inclined cylindrical body 60. Further, a chuck spring 64 is stretched between the step portion 59 c of the sliding body 59 and the flange portion 62 c of the chuck 62. By urging the chuck 62 rearward by the chuck spring 64, the chuck 62 is acted in the closing direction via the ball 63 in contact with the inclined surface 62 a of the inclined cylindrical body 62, and the core 75 is gripped. Yes. That is, a ball chuck mechanism that allows the lead to advance but prevents its retreat by a wedge action.
The chuck unit is urged forward by a slide body spring 65 disposed between the step portion 51 c of the outer shaft cylinder 51 and the flange portion 59 b of the slide body 59. The chuck unit is positioned when the stepped portion 61 a of the connecting member 61 contacts the positioning ring 58. Here, a protrusion 61 b is formed at the tip of the connecting member 61, and the protrusion 61 b protrudes from the through hole 58 a of the positioning ring 58. Further, the protruding portion 61 b of the connecting member 61 is in contact with the inclined plate 57. Therefore, the inclined plate 57 receives a rearward biasing force from the tip spring 56 via the rear end of the tip sliding body 53 with the fulcrum 52e of the tip member 52 as a fulcrum, and the protruding portion of the connecting member 61 By receiving a forward biasing force from the sliding body spring 65 through 61b, the posture inclined with respect to the central axis is maintained.

As described above, the lead tank unit includes the lead tank 66, the joint 67, and the knock member 68. A rear outer diameter portion 67 a of the joint 67 is press-fitted into the tip of the core tank 66. On the outer periphery of the joint 67, grooves 67b and 67c are provided in order from the front. In normal times, the inclined protrusion 59d of the sliding body 59 is engaged with the groove 67b, and the groove 67c is fitted to the inclined protrusion 59d of the sliding body 59 during the core feeding operation by the rear end knock. The shape of the joint 67 may be the same as that of the first embodiment. Further, a lead guide pipe 69 is inserted into the step portion 67 d of the joint 67, and plays a role of making it easy to insert the lead stored in the lead tank 66 into the chuck 62.
Furthermore, the front end portion 68a of the knock member 68 is fixed to the rear end of the lead tank 66 so as not to be detachable. An eraser 72 is attached to the inside of the enlarged diameter portion 68b formed on the rear side of the knock member 68, and a knock cover 73 is detachably attached to the outside.
The lead tank unit is urged rearward by a knock spring 70 stretched between the step portion 51 d of the outer shaft cylinder 51 and the flange portion 66 a of the lead tank 66. In addition, the lead tank unit is positioned by the flange 66a of the lead tank 66 coming into contact with the retaining member 71 press-fitted and fixed to the rear enlarged diameter portion 51f of the outer shaft cylinder 51. The shape of the retaining member 71 is not limited to a cylindrical shape, and a ring having a C-shaped cross section or a plurality of members can be used. Alternatively, after the core tank unit is inserted, the outer shaft cylinder 51 can be used. The rear end may be formed by caulking so that the inner diameter is narrower than the flange 66a of the core tank 66. That is, it is only necessary to prevent the lead tank unit from falling off the outer shaft cylinder 51. Further, at the time of the rear end knocking operation, the stepped portion 51e of the outer shaft cylinder 51 and the flange portion 66a of the lead tank 66 abut against each other, thereby preventing the rear end knock from being pushed excessively.

Here, the biasing force of each spring, the core holding force of the core holding member 54, the locking force brought about by the fitting of the inclined protrusion 59d of the sliding body 59 and the groove 67c of the joint 67, the core gripping force of the ball chuck mechanism The order of each force will be described in detail. The following magnitude relationship is required in order from the weakest.
The biasing force of the chuck spring 64 is weaker than the core holding force of the core holding member 54, and the core holding force is set to be weaker than the biasing force of the tip spring 56. The urging force of the tip spring 56 is set to be weaker than the urging force of the sliding body spring 65. Further, the urging force of the sliding body spring 56 is set to be weaker than the locking force caused by the fitting between the inclined projection 59d of the sliding body 59 and the groove 67c of the joint 67. In addition, the locking force is It is set to be weaker than the urging force of the knock spring 70. Furthermore, the urging force of the sliding body spring 56 is set to be weaker than the gripping force when the core is retracted when the core is retracted.
In the configuration of the present embodiment, the inclined plate 57 receives the pressing force from the tip sliding body 53 and the protruding portion 61b of the connecting member 61 with the fulcrum 52e of the tip member 52 as a fulcrum, and exhibits a lever action. For this reason, the ratio of the distance between the inclined plate 57 and the fulcrum (A (fulcrum 52e) in FIG. 10 and the contact points (B, C in FIG. 10) with the connecting member 61 and the sliding body 53 is the force relationship of the spring. Specifically, the value obtained by multiplying the ratio of the distance AC to the distance AB by the biasing force of the tip spring 56 is set to be weaker than the biasing force of the sliding body spring 65.

Next, the operation of feeding the lead by advancing the lead tank by the rear end knock in the fourth embodiment of the present invention will be described. 11 to 14 are operation diagrams of the rear end knocking operation.

When the knock cover 73 is pressed to push out the lead 75 (rear end knock), the lead tank 66 moves forward against the resilient force of the knock spring 70. As the lead tank 66 advances, the groove 67b of the joint 67 disengages from the inclined protrusion 59d of the sliding body 59, and the tip of the joint 67 abuts against the rear end of the chuck 62 (FIG. 11). At this time, the chuck 62 is closed by the wedge action of the inclined surface 60 a of the inclined cylindrical body 60 and the ball 63 and is in a state of gripping the core 75.

Further, when the pressing force to the knock cover 73 is increased, the chuck 62 is advanced against the urging force of the chuck spring 64 by the joint 67 (FIG. 12).
As the chuck 62 moves forward, gaps are formed between the recess 62a of the chuck 62 and the ball 63, and between the ball 63 and the inclined surface 60a of the inclined cylindrical body 60, and the wedge effect of the ball chuck mechanism is reduced. The chuck 62 is released and the chuck 62 is expanded. That is, at this time, the chuck 62 releases the lead 75. At the same time, the groove 67c of the joint 67 and the inclined protrusion 59d of the sliding body 59 are fitted, and the core tank unit and the chuck unit are locked together. Further, at this time, the step portion 51e of the outer cylinder 51 and the flange portion 66a of the lead tank 66 come into contact with each other, so that the user cannot push the knock cover 73 excessively.

Next, when the pressing force to the knock cover 73 is released, the lead tank unit and the chuck unit are moved backward by the urging force of the knock spring 70 while being integrated. When the rear end of the sliding body 59 comes into contact with the stepped portion 51d of the outer shaft cylinder 51, the chuck unit is prevented from retreating (FIG. 13). At this time, since the chuck 62 remains expanded, the lead 75 does not retract in the retreat operation of the chuck unit.
On the other hand, as the chuck unit moves backward, the tip of the protruding portion 61 b of the connecting member 61 moves backward until it is positioned behind the front end of the positioning ring 58. Since the protruding portion 61b of the connecting member 61 is separated from the inclined plate 57, the forward biasing force applied to the inclined plate 57 is released. The inclined plate 57 is retracted together with the tip sliding body 53 by the biasing force of the tip spring 56. As a result, the entire rear end portion of the inclined plate 57 contacts the positioning ring 58. That is, the inclined plate 57 swings around the fulcrum 52e of the tip member 52 and stands upright inside the tip member 52. At this time, the tip sliding body 53 also moves backward, but the lead holding member 54 press-fitted and fixed inside the tip sliding body 53 grips the lead 75 and moves backward.
By the operation of the chuck unit and the tip sliding body 53, the core 75 is retracted by the same amount as the receding distance (L1) of the tip sliding body 53.

Even after the chuck unit is prevented from retreating, the lead tank unit continues to retreat due to the urging force of the knock spring 70. In the process of the backward movement, the inclined protrusion 59d of the sliding body 59 is detached from the groove 67c of the joint 67. Then, the lead tank unit moves backward until the flange 66a of the lead tank 66 contacts the retaining member 71 and returns to the original state.
On the other hand, since the pressing force by the joint 67 is removed, the chuck 62 is retracted by the elastic force of the chuck spring 64, and the chuck unit again exhibits a wedge action and grips the core 75. Further, since the backward biasing force received from the knock spring 70 via the joint 67 is eliminated, the chuck unit is advanced by the elastic force of the sliding body spring 65, and the step portion 61a of the connecting member 61 is It contacts the positioning ring 58 and returns to the original position. That is, since the chuck 62 moves forward while holding the lead 75, the lead 75 also moves forward by the length indicated by L2 (FIG. 14).
Further, when the chuck unit moves forward, the protruding portion 61b of the connecting member 61 is again protruded from the through hole 58a of the positioning ring 58. Then, an urging force toward the front of the sliding body spring 65 is again applied to the inclined plate 57 via the protruding portion 61 b of the connecting member 61. Further, the inclined plate 57 swings around the fulcrum 52e of the tip member 52 to return to the original posture, and pushes the tip sliding body 53 forward. At this time, the core holding member 54 press-fitted and fixed to the tip sliding body 53 holds the core 75. That is, the lead 75 is also advanced by the same distance (L1) as the forward sliding body 53 is advanced. Here, a section (L3) from when the protruding portion 61b of the connecting member 61 starts to protrude from the through hole 58a of the positioning ring 58 to when the stepped portion 61a of the connecting member 61 contacts the positioning ring 58 is a chuck unit. And the tip sliding body 53 are moving forward simultaneously. That is, the core 75 is advanced only for the section L3, but is relatively advanced, so that substantial feeding is not performed.
That is, in the rear end knocking operation in the present embodiment, first, the lead moves backward by L1, and then advances by (L3 + L1-L2). That is, the length of the core protruding from the tip of the core protection tube 55 by the rear end knock is (L2-L3).

Next, an operation (hereinafter referred to as “tip knock”) of pushing out the lead by pressing the lead against the paper surface in the present embodiment will be described. 15 and 16 are operation diagrams of the tip knocking operation.

In order to feed out the lead, the tip of the lead 75 protruding from the tip of the lead protection tube 55 is strongly pressed against the paper surface 76. This pressing force is transmitted from the lead 75 to the chuck 62, and the chuck 62 tends to move backward. However, due to the wedge action of the inclined surface 60a of the inclined cylindrical body 60 with which the ball 63 interposed in the semicircular recess 62a on the front outer peripheral surface of the chuck 62 abuts, the chuck 62 is firmly closed and the core 75 cannot be retracted. Grip firmly. That is, the retraction of the lead 75 is prevented by the wedge action.
Further, when the pressing force applied by the user to the paper surface 76 is increased and the pressing force exceeds the urging force of the sliding body spring 65 that urges the chuck unit forward, the chuck unit moves backward. By the retraction of the chuck unit, the lead 75 gripped by the chuck 62 is also retracted.
As the chuck unit is retracted, when the connecting member 61 is retracted and the tip of the protruding portion 61b is flush with the positioning ring 58, the forward biasing force applied to the inclined plate 57 is released. (FIG. 15). For this reason, the inclined plate 57 is retracted together with the distal end sliding body 53 by the urging force of the distal end spring 56, and the inclined plate 57 is brought into a state where the entire rear end portion is in contact with the positioning ring 58. That is, the inclined plate 57 swings with the fulcrum 52e of the tip member 52 as a fulcrum, and stands upright inside the tip member 52.
At this time, due to the lever action of the inclined plate 57, the tip sliding body 53 is retracted to a greater extent than the retracting amount (L4) of the chuck unit (L5). Here, since the chuck 62 prevents the lead 75 from moving backward, only the sliding body 53 moves backward. At this time, the lead holding member 54 fixed inside the sliding body 53 is used as the lead holding member 54. It slides so as to slide on the surface of 75. That is, at this time, since the retraction amount (L5) of the sliding body 53 is larger than the retraction amount (L4) of the lead, the difference (L4-L5) lead is drawn out.

Next, when the operation of pressing the core 75 against the paper surface 76 is finished and the pressing force is released, the chuck unit moves forward by the urging force of the sliding body spring 65. When the chuck unit advances, the protruding portion 61b of the connecting member 61 is again protruded from the through hole 58a of the positioning ring 58. Then, an urging force toward the front of the sliding body spring 65 is again applied to the inclined plate 57 through the protruding portion 61 b of the connecting member 61. Further, the inclined plate 57 swings around the fulcrum 52e of the tip member 52 to return to the original posture, and pushes the tip sliding body 53 forward. At this time, the core holding member 54 press-fitted and fixed to the tip sliding body 53 holds the core 75, and the ball chuck mechanism allows the core 75 to advance, so that the core 75 is pulled out from the chuck 62. That is, as described above, the tip sliding body 53 moves forward to the original position while the length of the core protruding from the core protection tube 55 is extended by (L4-L5), and the tip knocks. The lead out is completed.
When the pressing force applied to the paper surface 76 is further increased from the state shown in FIG. 15, the rear end of the sliding body 59 comes into contact with the stepped portion 51 d of the outer shaft cylinder 51, thereby restricting the backward movement of the chuck unit. And excessive push-in is prevented. In this case, the chuck unit that holds the lead 75 moves backward while the lead 75 slides on the lead holding member 54. When the pressing force is released, the chuck unit is moved forward by the urging force of the sliding body spring 65 while holding the lead 75, and returns to the state shown in FIG.
Further, in this embodiment, in order to draw out the lead 75 during writing, an operation of strongly pressing the tip of the lead 75 against the paper surface 76 is adopted. However, by properly adjusting the biasing force of the sliding body spring 65, the writing is performed. It is also possible to automatically unwind the core by the natural movement inside. Specifically, by setting the urging force of the sliding body spring 65 to be weaker than the writing pressure (that is, the pressure when the core touches the paper surface during writing), the operation of pushing the tip knock during writing is performed. What happens is that the lead is drawn out when the lead is released from the page to move to the next line of writing.

FIG. 17 is a longitudinal sectional view showing the configuration of the fifth embodiment of the present invention, and FIG. 18 is a perspective view of a lock member and a knock member which are features of the present embodiment.
A front member 78 is fixed in front of the outer shaft cylinder 77. The tip member 78 has a core holding member 79 press-fitted inside, and a core protection tube 80 fixed to the tip. A chuck unit including a sliding body 81, a chuck ring 82, a chuck 83, a spring retainer 84, and a chuck spring 85 is slid in the front-rear direction inside the tip member 78 and behind the core holding member 79. Arranged freely. The chuck unit is urged forward by a sliding body spring 86 disposed behind the sliding body 81. A lead tank unit including a lead tank 87, a joint 88, and a lock member 89 is disposed behind the slide body 81 so as to be slidable in the front-rear direction inside the outer shaft cylinder 77. Further, a knock spring 90 is disposed on the outer periphery of the core tank 87, and a knock member 91 is disposed behind the lock member 89. A retaining member 92 is disposed on the outer periphery behind the flange 91a of the knock member 91. Further, an eraser 93 is inserted into the rear end of the knock member 91, and a knock cover 94 is detachably disposed at the rear end of the knock member 91 so as to cover the eraser 93. A clip 95 is fixed behind the outer shaft cylinder 77. The configuration of the present embodiment is as described above. In the present embodiment, the lock member 89 is attached to the rear of the core tank 87, and the knock member 91 is disposed on the rear thereof. It is different from the example. By adopting this structure, by rotating the knock member 91, it is possible to add a so-called lock function that prevents the lead from being pulled out due to a malfunction when not in use.
Further, each member will be described. Here, the configuration of the present embodiment is characterized by the configuration of the rear portion, and the configuration of the portion of the tip member 78 and the chuck unit is the same as that of the first embodiment, and thus detailed description thereof is omitted.

As described above, the lead tank unit includes the lead tank 87, the joint 88, and the lock member 89. A rear outer diameter portion 88 a of the joint 88 is press-fitted into the front inner diameter portion 87 a of the core tank 87. The front side surface 88b of the joint 88 is provided with a groove 88c on the outer periphery, and the groove 88c fits with the inclined protrusion 81a of the sliding body 81 during the core feeding operation by the rear end knock as in the first embodiment. Match.
Further, a rear end 89a of the lock member 89 is fixed to the rear of the core tank 87 so as not to be attached and detached. On the outer periphery of the lock member 89, a step portion 89b and a longitudinal rib 89c are formed, an inclined surface 89d is formed at the rear, and a concave portion 89e is formed at the top of the inclined surface 89d. Since the rib 89c of the lock member 89 is engaged with a groove (not shown) in the longitudinal direction (axial direction) provided on the inner surface of the outer shaft cylinder 77, the core tank unit is connected to the outer shaft cylinder 77. Although it is allowed to move back and forth internally, movement in the rotational direction is limited. Further, a knock member 91 is disposed behind the lock member 89 so as to be movable back and forth within the outer shaft cylinder 77 and rotatable with respect to the central axis. The knock member 91 has flanges 91a and 91b formed on the outer periphery, an inclined surface 91c on the front side, and a protrusion 91d on the top of the inclined surface 91c. An eraser 93 is attached to the rear end of the knock member 91, and a knock cover 94 is detachably attached to the flange 91b.
The core tank unit is urged rearward by a knock spring 90 stretched between a step portion 77 a of the outer shaft cylinder 77 and a step portion 89 b of the lock member 89. Further, since the inclined surface 89d of the lock member 89 and the inclined surface 91c of the knock member 91 are opposed to each other, the knock member 91 is also urged rearward. The hook portion 91 a of the knock member 91 abuts against a retaining member 92 fixed to the step portion 77 b of the outer shaft cylinder 77, whereby the core tank unit and the knock member 91 are positioned, and the outer shaft cylinder 77 is positioned. Dropping from is prevented. The shape of the retaining member 92 is not limited to a cylindrical shape, and it is possible to use a ring having a C-shaped cross section or a plurality of members, or after inserting the core tank unit, The rear end may be formed to be narrower than the flange 91a of the knock member 91 by caulking. That is, it is only necessary to prevent the lead tank unit and the knock member 91 from falling off the outer shaft cylinder 77.

Next, the operation in the fifth embodiment of the present invention will be described. First, the lead-out operation by the rear end knock is the same as that in the first embodiment, and thus the description thereof is omitted. The operation different from that of the first embodiment by adopting the configuration of the present embodiment is a mechanism (lock mechanism) that prevents the lead from being pulled out due to a malfunction when not in use, and details thereof will be described below.

FIG. 19 is an operation diagram of the lock mechanism. When the knock member 91 is rotated to finish the writing and operate the lock mechanism, the direction of the inclined surface 91c changes. However, since the rotation of the lock member 89 is restricted by the rib 89c, the inclined surface 89d of the lock member 89 is not rotated around the inclined surface 91c of the knock member 91. Therefore, the lock member 89 is pressed against the tip of the inclined surface 91c of the knock member 91, and the knock spring 90 cannot be resisted, and the lock member 89 moves forward. As the lock member 89 moves forward, the joint 88 of the lead tank unit moves forward, and eventually the tip of the joint 88 comes into contact with the spring retainer 84. When the knock member 91 is further rotated, the joint 88 further advances, and the spring retainer 84 is pushed forward, and the spring retainer 84 and the chuck 83 are advanced against the chuck spring 83 (FIG. 19). Therefore, the tapered portion 83a of the chuck 83 is detached from the chuck ring 82, and the chuck 83 is expanded to release the core 96. At the same time, the protrusion 91d of the knock member 91 is fitted into the recess 89e of the lock member 89, and the lock member 89 and the knock member 91 are locked. That is, the state where the chuck 83 is expanded can be maintained, and as a result, the lead 96 can be stored by pushing the tip of the lead 96, and thereafter, the lead of the lead due to a malfunction can be prevented. Incidentally, the rotation angle of the knock member 91 with respect to the outer shaft cylinder 77 at this time is 180 degrees. In this embodiment, in order to limit the rotation of the knock member 91 in the locked state, the locking effect by the fitting of the protrusion 91d of the knock member 91 and the recess 89e of the lock member 89 is used. As long as the rotation can be restricted, locking means having a different structure may be used. For example, it is possible to provide a protrusion on the side surface of the knock member 91 and to fit the protrusion into a recess formed on the inner surface of the outer shaft cylinder 77. Furthermore, in order for the lock mechanism to operate, the core tank unit is maintained in the advanced state until the tip of the joint 88 is advanced by pressing the spring retainer 84 and the chuck 83. Good. Therefore, for example, the clip 95 can be configured to be interlocked with the lead tank unit and locked at the advanced position. Alternatively, the clip 95 may be configured such that the outer cylinder 77 serves as a fulcrum and the lead tank unit serves as an action point, and a means for moving the lead tank unit forward by lifting the clip may be employed.

In the operation of the lock mechanism, the chuck 83 is expanded, the groove 88a of the joint 88 and the inclined protrusion 81a of the sliding body 81 are fitted, and the core tank unit and the chuck unit are integrally engaged. It has been stopped.
Here, when the knock member 91 is rotated and returned to the original position in order to release the locked state, the lead tank unit and the chuck unit are moved backward by the urging force of the knock spring 90 while being integrated. Thereafter, the same movement as the rear end knocking operation described in detail in the first embodiment is taken, and the lead is fed out. That is, the lead can be automatically extended by releasing the locked state.

  In this embodiment, the structure of the lock mechanism is added to the structure described in detail in the first embodiment, but the same lock mechanism is added in the structures shown in the second to fourth embodiments. Is possible.

1, 20, 35, 51, 77 Outer cylinder 2, 21, 36, 52, 78 Tip member 3, 22, 38, 54, 79 Core holding member 4, 23, 39, 55, 80 Core protective tube 5, 24 , 40, 59, 81 Slider 6, 82 Chuck ring 7, 27, 43, 62, 83 Chuck 8, 84 Spring retainer 9, 29, 45, 64, 85 Chuck spring 10, 30, 47, 65, 86 Slider Spring 11, 31, 48, 66, 87 Core tank 12, 32, 49, 67, 88 Joint 13, 68, 91 Knock member 14, 70, 90 Knock spring 15, 71, 92 Retaining member 16, 72, 93 Eraser 17, 73, 94 Knock cover 18, 74, 95 Clip 19, 34, 50, 75, 96 Core 25, 41, 60 Inclined cylindrical body 26, 42, 61 Connecting member 28, 4 , 63 Ball 33,69 lead guide pipe 37,53 tip sliding body 46, 56 distal spring 57 inclined plate 58 positioning ring 76 paper 89 locking member

Claims (6)

In the mechanical pencil in which the chuck unit for preventing the retraction of the core is arranged in the shaft cylinder, the chuck body of the chuck unit is retracted in the expanded state in the process of extending the core, and then the chuck body is closed. Mechanical pencil with a chuck unit moving means that moves forward while holding the lead. The mechanical pencil according to claim 1, wherein a slit is formed in front of the chuck body of the chuck unit, and the chuck is opened and closed by a chuck ring disposed in front of the chuck body. 2. The mechanical pencil according to claim 1 , wherein the chuck unit is a ball chuck mechanism that allows the lead to advance but prevents the lead from retreating by a wedge action. The mechanical pencil according to any one of claims 1 to 3 , wherein a sliding member including a core holding member is disposed in a tip member attached to the front side of the shaft tube so as to freely move back and forth. A stepped portion is formed inside the tip member, and a disk-shaped member that can swing with the stepped portion as a fulcrum is disposed behind the sliding member, and by swinging the disk-shaped member, The mechanical pencil according to claim 4 , wherein the sliding member moves forward or backward. The mechanical pencil according to any one of claims 1 to 5 , wherein a locking means for maintaining an expanded state of the chuck body of the chuck unit is disposed.

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