JP2020093477A - mechanical pencil - Google Patents

Abstract

To provide a mechanical pencil having a lead delivery mechanism constituted so as to prevent rotation of a rotary drive mechanism from being hindered.SOLUTION: A mechanical pencil 1 includes: a ball chuck 11; a rotary drive mechanism 30 having a rotator 40 to rotate and drive the rotator in one direction; a delivery cam surface 70 having an annular cam face 62 and a step 71 disposed on the annular cam face in an axial direction; and a slider 9 having a contact element 9c brought into contact with the delivery cam surface and a holding chuck 10 for holding a writing lead to be rotated by receiving a rotary driving force of the rotator. The contact element moves along the annular cam face according to rotation of the rotator to be constituted so as to withdraw the writing lead held by the holding chuck from the ball chuck by an advancing operation of the slider when the contact element falls in the step, and the rotary driving force is transmitted from the rotator to the slider via an elastic member.SELECTED DRAWING: Figure 14

Description

This invention relates to mechanical pencils.

In the mechanical pencil, for example, by knocking a knock portion provided at the rear end of the barrel, a certain amount of the writing core is fed from the tip member attached to the front end of the barrel. Since the writing core wears along with the writing operation, it is necessary to perform a knocking operation every fixed amount of writing operation. Various studies have heretofore been made on the optimum amount of the writing core to be fed out by one knock operation. If the amount of extension of the writing core by one knocking operation is large, there is a problem that the writing core is frequently broken due to the writing pressure. Further, if the amount of extension of the writing core by one knocking operation is small, it is necessary to repeat the knocking operation frequently due to the abrasion of the writing core by the writing operation, which causes a problem that the knocking operation is troublesome.

Therefore, along with the protruding action of the writing lead accompanying the knocking operation, the pipe-shaped lead guide attached to the tip member moves forward, and the lead guide moves backward along with the abrasion of the writing lead accompanying writing. Pencils are known (see Patent Documents 1 and 2). In the mechanical pencils described in Patent Document 1 and Patent Document 2, the tip of the lead guide comes into contact with the paper surface due to the wear of the writing lead accompanying writing, and the lead guide operates so as to gradually retract. Therefore, even if the amount of extension of the writing core by a single knocking operation is set to be slightly large, the writing core is protected by the core guide and is less likely to break.

However, in the mechanical pencils described in Patent Document 1 and Patent Document 2, since the core guide is formed of metal such as stainless steel, when the tip end of the core guide comes into contact with the paper surface, the pencil guide receives the frictional resistance of the brush. Feeling bad. Further, there is a problem that the leading end of the lead guide is caught on the paper surface and damages the paper surface.

On the other hand, by causing the lead guide to gradually retract into the tip member with the wear of the writing lead, the amount of protrusion of the writing lead from the lead guide can be maintained within a certain range. Pencils are known (see Patent Document 3). In the mechanical pencil described in Patent Document 3, the writing pressure applied to the writing lead is used to gradually retract the tip pipe that functions as a lead guide into the tip member. Therefore, since the tip pipe retreats according to the abrasion of the writing core, it is possible to prevent the tip pipe from coming into contact with the paper surface, and it is also possible to prevent the writing core from breaking.

However, in the mechanical pencil described in Patent Document 3, although the tip pipe also retracts in accordance with the wear of the writing core, it is possible to continue writing for a long time, but when the writing core wears to a certain extent, after all, a knock operation is performed. Need to The knocking operation causes the writing core and the tip pipe to be largely fed out from the tip member, so that the feeling of another writing may be uncomfortable due to the position of the tip portion of the writing core.

On the other hand, a mechanical pencil is known in which the writing core can be sequentially fed out by utilizing the writing pressure accompanying the writing operation (see Patent Document 4). The mechanical pencil described in Patent Document 4 has a ball chuck that holds a writing core, an axial backward movement operation due to writing pressure received by the writing core held by the ball chuck, and an axial forward movement operation due to release of the writing pressure. A rotary drive mechanism that receives and drives the rotor to rotate in one direction, and a lead feed mechanism that includes a cam member and a holding chuck that feeds the writing lead forward in response to the rotary drive force of the rotor in the rotary drive mechanism. doing.

The lead-out mechanism includes a cam member having a cam surface that rises along the circumferential direction and a step in the axial direction, and a slider that has an abutment. The slider is biased forward by a spring, so that the contactor is in contact with the cam surface. Further, the slider is connected to the rotary drive mechanism, and is rotated by the rotary drive of the rotary drive mechanism. At this time, the contactor operates so as to rise along the cam surface of the cam member, and the slider gradually retracts in the axial direction accordingly.

Then, when the slider abutment reaches the step of the cam member, the abutment falls along the step due to the action of the spring for urging the slider, and at that moment, the slider also moves forward corresponding to the height difference of the step. Receive. At this time, the holding chuck arranged in the slider also moves forward, so that the writing core held in sliding contact with the holding chuck is pulled out from the ball chuck, and the writing core is fed.

JP-A-8-072473 JP-A-8-132782 JP, 2009-233921, A JP, 2016-153246, A

In the mechanical pencil described in Patent Document 4, the slider is biased forward by the spring as described above in order to surely bring the contactor into contact with the cam surface. Therefore, as compared with a mechanical pencil having a rotary drive mechanism that does not have a lead-out mechanism, a higher writing pressure is required by the biasing force of the spring. Further, since the contactor is pressed against the cam surface by the spring, frictional resistance is generated when the slider is rotated by the rotation drive mechanism. Therefore, the rotation of the rotary drive mechanism may be hindered. Further, since the cam surface is formed so as to rise along the circumferential direction, in addition to the frictional resistance, the component force in the direction against the urging force of the spring becomes a factor that hinders the rotation of the rotary drive mechanism.

It is an object of the present invention to provide a mechanical pencil having a lead-out mechanism configured so as not to hinder the rotation of a rotary drive mechanism.

According to one aspect of the present invention, a ball chuck that allows the writing lead to move forward and prevents the writing lead from moving backward, and a backward movement in the axial direction due to the writing pressure received by the writing lead held by the ball chuck and a rotor are provided. A feed-out having a rotation drive mechanism for rotating and driving the rotor in one direction in response to an axial forward movement due to release of writing pressure, an annular cam surface, and an axial head provided on the annular cam surface. A cam surface; and a slider that has a contactor that contacts the feeding cam surface and a holding chuck that holds a writing core, and that rotates by receiving the rotational driving force of the rotor. The writing core held by the holding chuck is moved from the ball chuck by the forward movement of the slider that moves along the annular cam surface according to the rotation of the rotor and the abutment falls into the drop. There is provided a mechanical pencil which is configured to be pulled out, and in which transmission of a rotational driving force from the rotor to the slider is performed via an elastic member.

According to another aspect of the present invention, the annular cam surface may be formed perpendicular to the axial direction. The elastic member may be a torsion spring. The ball chuck may be configured to rotate the writing core by being rotated by receiving the rotational driving force of the rotor.

According to the aspects of the present invention, there is a common effect of providing a mechanical pencil having a lead-out mechanism configured so as not to hinder the rotation of the rotary drive mechanism.

FIG. 1 is a vertical cross-sectional view of a mechanical pencil according to an embodiment of the present invention. FIG. 2 is an enlarged sectional view of the rear half of the mechanical pencil shown in FIG. FIG. 3 is an enlarged sectional view of the front half of the mechanical pencil shown in FIG. FIG. 4 is a perspective view illustrating the internal structure of the mechanical pencil. FIG. 5 is an enlarged cross-sectional view of the rotary drive mechanism. FIG. 6 is a schematic diagram for explaining the rotational drive of the rotor of the rotary drive mechanism. FIG. 7 is a schematic diagram for explaining the rotational drive of the rotor following FIG. FIG. 8 is a perspective view of the dial cam member. FIG. 9 is a perspective view of the rail cam member. FIG. 10 is another perspective view of the rail cam member. FIG. 11 is a perspective view of the combined dial cam member and rail cam member. FIG. 12 is a schematic diagram showing the delivery cam surface when the delivery amount is large. FIG. 13 is a schematic diagram showing the delivery cam surface when the delivery amount is small. FIG. 14 is a schematic diagram showing the relationship between the feeding cam surface and the movement of the contactor. FIG. 15 is a schematic view showing another feeding cam surface.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Corresponding components are designated by common reference numerals throughout the drawings.

1 is a longitudinal sectional view of a mechanical pencil 1 according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a front half of the mechanical pencil 1 of FIG. 1, and FIG. 3 is a mechanical pencil 1 of FIG. FIG. 4 is an enlarged cross-sectional view of the rear half, and FIG. 4 is a perspective view illustrating the internal structure of the mechanical pencil 1.

The mechanical pencil 1 includes a front shaft 2, a rear shaft 3 screwed onto the outer peripheral surface of the rear end of the front shaft 2, a tip member 4 screwed onto the outer peripheral surface of the front end of the front shaft 2, and a rear shaft 3. It has an inner cylinder 5 fitted to the inner peripheral surface of the rear end portion. The front shaft 2 and the rear shaft 3 form a shaft cylinder 6. The tip member 4 or the inner cylinder 5 may also be referred to as the shaft cylinder 6. As will be described later, the mechanical pencil 1 is configured such that the writing core 7 projects from the tip of the tip member 4. The vicinity of the tip of the writing core 7 is covered with a tip pipe 8 that guides the writing core 7. In the present specification, in the axial direction of the mechanical pencil 1, the writing core 7 side is defined as the “front” side, and the side opposite to the writing core 7 side is defined as the “rear” side.

Referring to FIG. 2, a slider 9 is arranged inside the front end of the shaft tube 6 so as to be slidable in the axial direction and rotatable about the axis. The slider 9 is formed in a cylindrical shape whose outer diameter is reduced in a stepwise shape toward the front. The tip pipe 8 is attached to the tip 9 a of the slider 9. Further, behind the tip pipe 8 in the tip portion 9a, a rubber holding chuck 10 having a through hole formed in the center is arranged. The through hole of the holding chuck 10 is in sliding contact with the outer peripheral surface of the writing core 7 and acts to temporarily hold the writing core 7.

An abutment member 9c projecting in the axial direction is formed integrally with the slider 9 at the rear portion of the outer peripheral surface of the intermediate portion 9b behind the tip portion 9a of the slider 9, particularly at the root portion of the intermediate portion 9b. A dial cam member 50, which is a first cam member formed in a cylindrical shape, and a rail cam member 60, which is a second cam member formed in an annular shape, are provided on the outer peripheral surfaces of the tip portion 9a and the intermediate portion 9b in the axial direction. It is arranged in an aligned state. A part of the tip portion 9a of the slider 9 projects from the hole at the front end portion of the dial cam member 50.

Inside the slider 9, a ball chuck 11 for holding the writing core 7 and a relay member 12 formed in a cylindrical shape are arranged. The ball chuck 11 has a fastener 13 formed in a cylindrical shape, a chuck body portion 14 arranged in the fastener 13, a chuck holding portion 15 formed in a cylindrical shape, and a plurality of balls 16. ing. The inner peripheral surface of the fastener 13 is formed with a tapered surface that spreads forward. The chuck body 14 is formed with a through hole for the writing core 7 along the central axis, and the front end of the chuck body 14 is divided into a plurality along the axial direction. The rear end of the chuck body 14 is held by the chuck holder 15. The chuck body 14 and the chuck holder 15 are movable in the axial direction with respect to the fastener 13. The plurality of balls 16 are arranged between the inner peripheral surface of the fastener 13 and the outer peripheral surface of the chuck body 14.

When a writing pressure is applied to the writing core 7, the chuck main body 14 comes into contact with the tapered surface of the cylindrical fastener 13 together with the ball 16, so that the writing core 7 is gripped by the chuck main body 14. This prevents the writing lead 7 from retreating. On the other hand, when the force for pulling the writing core 7 forward is applied, the chuck main body 14 is not affected by the fastener 13, so that the writing core 7 can be pulled forward without resistance. That is, the ball chuck 11 acts so as to allow the writing lead 7 to move forward and prevent it from moving backward.

A coil spring 17 is arranged so as to surround the chuck body 14. The rear end of the coil spring 17 is fitted to the outer surface of the chuck body portion 14, and the front end of the coil spring 17 is supported by a step portion formed on the inner peripheral surface of the fastener 13. The coil spring 17 biases the chuck body 14 backward, and as a result, the ball chuck 11 can maintain the state in which the writing core 7 is held.

The outer peripheral surface of the rear end portion of the fastener 13 is fitted to the inner peripheral surface of the front end portion of the relay member 12. Therefore, the ball chuck 11 and the relay member 12 are movable in the slider 9 in the axial direction. A flange portion 12a is formed in the central portion of the relay member 12 in the axial direction. A cam contact spring 18, which is a coil spring, is arranged in front of the flange portion 12a so as to surround the relay member 12. The rear end of the cam contact spring 18 is attached to the flange portion 12a of the relay member 12 (A portion), and the front end of the cam contact spring 18 is attached to the inner wall of the rear end portion of the slider 9 ( Part B). The cam contact spring 18 biases the slider 9 forward in the barrel 6. As a result, the cam contact spring 18 acts so that the contactor 9c provided on the slider 9 contacts the cam surface, as described later. The rear end portion of the relay member 12 is connected to a rotation drive mechanism 30 described later. The front end of the lead case 19 is fitted to the outer peripheral surface of the rear end of the chuck holding portion 15. The lead case 19 is formed in a cylindrical shape, and the writing lead 7 is housed inside.

Referring to FIG. 3, a knock rod 20 as a knock member is slidably provided with respect to the shaft cylinder 6 at the rear end of the shaft cylinder 6, specifically, at the rear end of the inner cylinder 5. .. The knock rod 20 is biased rearward by a coil spring 21. A partition wall portion 20 a having a supply hole for the writing core 7 is formed near the rear end portion of the knock rod 20. An eraser 22 is removably attached inside the rear end of the knock rod 20. A knock cover 23 is detachably attached to the outer peripheral surface of the rear end portion of the knock rod 20 to protect the eraser 22 from dirt and the like. The knock rod 20 is fitted to the outer peripheral surface of the rear end of the lead case 19.

By performing a knocking operation of pushing the knocking rod 20 or the knocking cover 23 forward, the lead case 19 advances. As a result, the chuck body 14 is pushed forward through the chuck holding portion 15. Along with this, the writing core 7 gripped by the chuck body 14 also advances, and acts so as to let the writing core 7 extend from the tip pipe 8. When the pressing force due to the knock operation is released, the knock rod 20 retracts and returns to its original position by the biasing force of the coil spring 21.

At this time, the chuck body 14 is retracted by the biasing force of the coil spring 17. On the other hand, since the writing core 7 is held by the holding chuck 10 arranged in the slider 9, the writing core 7 is pulled out of the chuck body 14 without resistance as a function of the ball chuck 11. As a result, since the writing core 7 is fed from the tip pipe 8, the writing lead 7 can be fed by a predetermined amount each time the knocking operation is repeated. When the state where the knock rod 20 is advanced by the knock operation is maintained, the chuck body 14 projects from the fastener 13 and the writing core 7 is released from the grip. In this state, the writing core 7 in a state of being drawn out from the tip pipe 8 can be pushed back with a fingertip or the like.

FIG. 5 is an enlarged cross-sectional view of the rotary drive mechanism 30. The rotary drive mechanism 30 is arranged in the internal space of the rear shaft 3. The rotary drive mechanism 30 is connected to the rear end of the relay member 12. A shaft spring 31 is arranged between the rear end surface of the front shaft 2 and the front end surface of the rotary drive mechanism 30, and the rotary drive mechanism 30 is biased rearward. The rearward movement of the rotary drive mechanism 30 due to the urging force of the shaft spring 31 is restricted by the rear end surface of the rotary drive mechanism 30 contacting the front end surface of the inner cylinder 5. The lead case 19 penetrates the inside of the relay member 12 and the rotation drive mechanism 30, and is separated from the rotation drive mechanism 30.

The rotary drive mechanism 30 is a rotor 40 formed in a cylindrical shape, an upper cam forming member 41 which is a first cam forming member formed in a cylindrical shape, and a second cam forming member formed in a cylindrical shape. It has a lower cam forming member 42, a cylinder member 43 formed in a cylindrical shape, a torque canceller 44 formed in a cylindrical shape, and a coiled cushion spring 45. The rotary drive mechanism 30 is unitized by integrating these members.

The outer peripheral surface of the rear end portion of the relay member 12 is fitted to the inner peripheral surface of the front end portion of the rotor 40. The vicinity of the front end portion of the rotor 40 has a flange-shaped portion having a slightly larger diameter, a first cam surface 40a is formed on the rear end surface of the portion, and a second cam surface 40a is formed on the front end surface of the portion. A cam surface 40b is formed.

The upper cam forming member 41 rotatably surrounds the rotor 40 behind the first cam surface 40a of the rotor 40. The lower cam forming member 42 is fitted on the outer peripheral surface of the front end portion of the upper cam forming member 41. A fixed cam surface 41a, which is a first fixed cam surface, is formed on the front end surface of the upper cam forming member 41 that faces the first cam surface 40a of the rotor 40. A fixed cam surface 42a that is a second fixed cam surface is formed on the inner surface of the front end portion of the lower cam forming member 42 that faces the second cam surface 40b of the rotor 40.

A cylinder member 43 formed in a cylindrical shape is fitted on the outer peripheral surface of the rear end portion of the upper cam forming member 41. At the rear end of the cylinder member 43, an insertion hole 43a through which the lead case 19 can be inserted is formed. Inside the cylinder member 43, a torque canceller 44 that is formed in a cylindrical shape and is movable in the axial direction is arranged. A cushion spring 45 is arranged between the inner surface of the front end portion of the torque canceller 44 and the inner surface of the rear end portion of the cylinder member 43. The cushion spring 45 urges the rotor 40 forward through the torque canceller 44.

Here, the relay member 12 transmits the backward and forward movements (cushion movement) of the writing core 7 based on the writing movement to the rotary drive mechanism 30, that is, the rotor 40, and the rotor in the rotary drive mechanism 30 caused by the cushion movement. The rotational movement of 40 is transmitted to the ball chuck 11 with the writing core 7 held. Therefore, the writing core 7 held by the ball chuck 11 also rotates.

Except when writing with the mechanical pencil 1, that is, when the writing pressure is not applied to the writing core 7, the rotor 40 is positioned forward by the biasing force of the cushion spring 45 via the torque canceller 44. Therefore, the second cam surface 40b of the rotor 40 is brought into contact with the second fixed cam surface 42a and brought into a meshed state. When writing with the mechanical pencil 1, that is, when the writing pressure is applied to the writing core 7, the ball chuck 11 retreats against the urging force of the cushion spring 45, and the rotor 40 accordingly. fall back. Therefore, the first cam surface 40a of the rotor 40 is brought into contact with the first fixed cam surface 41a and brought into a meshed state.

FIG. 6 is a schematic diagram for sequentially explaining the rotational drive action of the rotor 40 of the mechanical pencil 1 of FIG. 1, and FIG. 7 is a schematic diagram for explaining the rotational drive action of the rotor 40 following FIG. 6. Is. In FIG. 6 and FIG. 7, the rear end surface, which is the upper surface of the rotor 40, is formed with a first cam surface 40a, which is continuously saw-toothed along the circumferential direction, in an annular shape. A second cam surface 40b, which is similarly saw tooth-shaped along the circumferential direction, is formed in an annular shape on the front end surface that is the lower surface.

The annular cam-shaped end surface of the upper cam forming member 41 facing the first cam surface 40a of the rotor 40 is also formed with the first fixed cam surface 41a continuously saw-toothed along the circumferential direction. On the annular end surface of the lower cam forming member 42 facing the second cam surface 40b, a second fixed cam surface 42a continuously formed in a sawtooth shape is formed along the circumferential direction. The cam surfaces of the first cam surface 40a and the second cam surface 40b formed on the rotor 40, the first fixed cam surface 41a formed on the upper cam forming member 41, and the first cam surface formed on the lower cam forming member 42. The two fixed cam surfaces 42a and the respective cam surfaces are formed so that their pitches are substantially the same.

FIG. 6(A) shows the relationship between the rotor 40, the upper cam forming member 41, and the lower cam forming member 42 when the writing pressure is not applied to the writing core 7. In this state, the second cam surface 40b formed on the rotor 40 is in contact with the second fixed cam surface 42a of the lower cam forming member 42 by the urging force of the cushion spring 45. At this time, the first cam surface 40a of the rotor 40 and the first fixed cam surface 41a of the upper cam forming member 41 are displaced by a half phase (half pitch) from one tooth of the cam in the axial direction. Is set to.

FIG. 6B shows an initial state in which a writing pressure is applied to the writing core 7 for writing with the mechanical pencil 1. In this state, the rotor 40 retracts by contracting the cushion spring 45 as the ball chuck 11 retracts. As a result, the rotor 40 moves to the first fixed cam surface 41a side of the upper cam forming member 41.

Next, FIG. 6C shows a state in which the writing pressure is further applied to the writing core 7 and the rotor 40 comes into contact with the first fixed cam surface 41 a of the upper cam forming member 41 and is retracted. In this state, the first cam surface 40a of the rotor 40 meshes with the first fixed cam surface 41a of the upper cam forming member 41. As a result, the rotor 40 receives rotational drive corresponding to a half phase (half pitch) of one tooth of the first cam surface 40a.

The circle marks drawn in the center of the rotor 40 in FIGS. 6 and 7 indicate the amount of rotational movement of the rotor 40. Then, in the state shown in FIG. 6C, the second cam surface 40b of the rotor 40 and the second fixed cam surface 42a of the lower cam forming member 42 have a half phase (in a phase) with respect to one tooth of the cam in the axial direction. It is set so that the relationship is shifted by (half pitch).

Next, FIG. 7D shows an initial state in which the writing with the mechanical pencil 1 is finished and the writing pressure on the writing core 7 is released. In this case, the rotor 40 moves forward by the urging force of the cushion spring 45. As a result, the rotor 40 moves to the lower cam forming member 42 side.

Next, FIG. 7(E) shows a state in which the rotor 40 is brought into contact with the first fixed cam surface 41a of the upper cam forming member 41 by the urging force of the cushion spring 45 and advanced. In this case, the second cam surface 40b of the rotor 40 meshes with the second fixed cam surface 42a of the lower cam forming member 42. As a result, the rotor 40 again receives the rotational drive corresponding to the half phase (half pitch) of one tooth of the second cam surface 40b.

Therefore, as indicated by the circles drawn in the center of the rotor 40, the rotor 40 reciprocates in the axial direction of the rotor 40 under the writing pressure, that is, back and forth movement. The writing core 7 gripped by the ball chuck 11 is also rotationally driven through the ball chuck 11 by receiving the rotational drive corresponding to one tooth (1 pitch) of the second cam surface 40b. Therefore, the rotor 40 undergoes a rotary motion corresponding to one tooth of the cam by one back-and-forth movement of the rotor 40 in the axial direction by writing, and by repeating this, the writing core 7 is sequentially driven to rotate. Therefore, it is possible to prevent the writing core 7 from being unevenly worn as the writing progresses, and it is possible to prevent the thickness of the drawn line and the thickness of the drawn line from being greatly changed.

The torque canceller 44 that pushes the rotor 40 forward by receiving the urging force of the cushion spring 45 causes a slip between the front end surface of the rotor 40 and the rear end surface of the rotor 40, so that the rotational movement of the rotor 40 is prevented. The transmission to the cushion spring 45 is prevented. That is, the torque canceller 44 prevents the rotational movement of the rotor 40 from being transmitted to the cushion spring 45, and thereby the torsion return (torque) of the cushion spring 45 that inhibits the rotational operation of the rotor 40 is generated. To prevent that.

As described above, the mechanical pencil 1 has the ball chuck 11 and the rotor 40, and by releasing and holding the writing core 7 by the forward and backward movement of the ball chuck 11, the writing core 7 can be fed forward. The ball chuck 11 is held in the barrel 6 so as to be rotatable around the central axis while holding the writing core 7, and the ball chuck 11 is interposed by the writing pressure of the writing core 7 The rotor 40 is rotated by the back and forth movement of the rotor 40, and the rotational movement of the rotor 40 is transmitted to the writing core 7 via the ball chuck 11.

The lead-out mechanism and the feed-out amount adjusting mechanism will be described with reference to FIGS. 8 to 10. The lead feeding mechanism receives the rotational driving force of the rotor 40 of the rotation driving mechanism 30 and acts to feed the writing lead 7 forward.

FIG. 8 is a perspective view of the dial cam member 50. The dial cam member 50 is arranged so that the upper side thereof is the rear side of the mechanical pencil 1 in FIG. The dial cam member 50 is a member formed in a cylindrical shape, and has a grip portion 50a having a plurality of grooves extending in the axial direction as slip stoppers, and a diameter smaller than the grip portion 50a behind the grip portion 50a. The small diameter portion 50b, the flange portion 50c formed on the small diameter portion 50b, the two fitting protrusions 50d formed on the rear end surface of the flange portion 50c, and the cam forming portion formed on the rear end surface of the small diameter portion 50b. It has a certain dial cam 51. The two fitting protrusions 50d are arranged symmetrically around the central axis.

The dial cam 51 has a recess formed in the rear end surface of the small diameter portion 50b, that is, the rear end surface of the dial cam member 50. Specifically, the dial cam 51 is formed stepwise by three bottom surfaces provided in the recess. The bottom surface of the deepest recess is the first cam bottom surface 51a, the bottom surface of the next deepest recess is the second cam bottom surface 51b, and the bottom surface of the next deepest recess is the third cam bottom surface 51c. The lengths of the bottom surfaces of the first cam bottom surface 51a, the second cam bottom surface 51b, and the third cam bottom surface 51c, that is, the lengths along the circumferential direction are substantially equal. On the rear end surface of the small diameter portion 50b, the same concave portion, that is, the dial cam 51 is further formed symmetrically around the central axis. What actually functions as a cam is the dial cam 51 formed in one of the recesses, and is arbitrarily selected during assembly. The rear end surface of the small diameter portion 50b also constitutes a part of the dial cam 51 as the rear end cam surface 51d.

FIG. 9 is a perspective view of the rail cam member 60, and FIG. 10 is another perspective view of the rail cam member 60. The rail cam member 60 is arranged so that the upper side thereof is the rear side of the mechanical pencil 1 in FIG. 9. The rail cam member 60 is a member formed in an annular shape. On the front end surface of the rail cam member 60, two adjustment recesses 60a are formed symmetrically around the central axis. Each of the adjustment recesses 60a is composed of four fitting recesses 60b arranged in parallel along the circumferential direction.

On the rear end surface of the rail cam member 60, an annular peripheral wall 60c and a rail cam 61 formed radially inward of the peripheral wall 60c and facing rearward are formed. The rail cam 61 has a flat annular cam surface 62 and a recess 63 formed in the annular cam surface 62 in a stepwise manner. The annular cam surface 62 is a plane perpendicular to the axial direction. The concave portion 63 is formed in a stepped shape by the two bottom surfaces. The bottom surface of the deeper recess is the first bottom surface 63a, and the bottom surface of the shallower recess is the second bottom surface 63b. The length of the first bottom surface 63a, that is, the length along the circumferential direction is longer than the length of the second bottom surface 63b, and the bottom surface of the first cam bottom surface 51a, the second cam bottom surface 51b, and the third cam bottom surface 51c. It is almost equal to each length.

FIG. 11 is a perspective view of the combined dial cam member 50 and rail cam member 60. The dial cam member 50 and the rail cam member 60 are arranged so that the upper side is the rear side of the mechanical pencil 1 in FIG. 11. The ring-shaped rail cam member 60 is inserted into the rear end portion of the small diameter portion 50b of the dial cam member 50, and is locked by the flange portion 50c to be assembled. That is, the front end surface of the rail cam member 60 contacts the rear end surface of the flange portion 50c of the dial cam member 50. More specifically, each of the fitting protrusions 50d provided on the flange portion 50c of the dial cam member 50 fits into one of the fitting recessed portions 60b of the adjustment recessed portions 60a of the rail cam member 60. Therefore, the rail cam member 60 is arranged radially outside the dial cam member 50.

In the state where the dial cam member 50 and the rail cam member 60 are combined, the rear end surface of the dial cam member 50 is arranged substantially flush with the annular cam surface 62 of the rail cam member 60 adjacent to each other in the radial direction. The dial cam 51 of the dial cam member 50 is arranged near the recess 63 of the rail cam member 60. As a result, the dial cam member 50, specifically, the dial cam 51, which is a cam forming portion, and the rail cam member 60, specifically, the rail cam 61, more specifically, the concave portion 63 cooperate with each other in the circumferential direction. At, a series or annular delivery cam surface 70 is constructed.

As shown in FIG. 2, the dial cam member 50 and the rail cam member 60 are arranged outside the tip portion 9a and the intermediate portion 9b of the slider 9 in a combined state. The outer peripheral surfaces of part of the dial cam member 50 and the rail cam member 60 are covered with the tip member 4. An O-ring 80 is arranged between the inner surface of the front end portion of the tip member 4 and the flange portion 50c of the dial cam member 50. Further, since the cam contact spring 18 biases the slider 9 forward, the contactor 9c of the slider 9 maintains a state of contacting the payout cam surface 70. The dial cam member 50 and the rail cam member 60 are restricted from moving rearward when the top surface of the peripheral wall 60c, which is the rear end surface of the rail cam member 60, contacts the front end surface of the front shaft 2. Further, the outer peripheral surface of the rail cam member 60 engages with the inner peripheral surface of the tip member 4, and the rotation of the rail cam member 60 with respect to the tip member 4, and thus the shaft cylinder 6, is restricted.

The shape of the feeding cam surface 70 can be changed by relatively rotating the dial cam member 50 and the rail cam member 60 around the central axis. That is, the user grips the barrel 6 with one hand and the grip 50a of the dial cam member 50 protruding from the tip of the barrel 6 with the other hand while holding the dial cam with respect to the barrel 6. The member 50 is rotated about the central axis. Since the rail cam member 60 is engaged with the shaft cylinder 6, the dial cam member 50 rotates about the central axis with respect to the rail cam member 60.

The rotation of the dial cam member 50 with respect to the rail cam member 60 causes the fitting protrusion 50d of the dial cam member 50 to move from one fitting recess 60b of the corresponding rail cam member 60 to the adjacent fitting recess 60b to be fitted. It will be done in stages. Therefore, the rotation of the dial cam member 50 around the central axis with respect to the rail cam member 60 is performed stepwise within the range of the adjustment recess 60a of the rail cam member 60 to which the fitting protrusion 50d of the dial cam member 50 is movable. Depending on the position of the fitting recess 60b of the rail cam member 60 with which the fitting protrusion 50d of the dial cam member 50 fits, the rail cam 61 of the rail cam member 60, specifically the recess 63, and the dial cam 51 of the dial cam member 50. The relative position to and changes, and as a result, the shape of the feeding cam surface 70 can be changed. The dial cam member 50 is urged against the rail cam member 60 by the O-ring 80, and a click feeling is obtained when the dial cam member 50 is gradually rotated with respect to the rail cam member 60. The modification of the shape of the feeding cam surface 70 will be further described with reference to FIGS. 12 and 13.

12 is a schematic diagram showing the delivery cam surface 70 when the delivery amount is large, and FIG. 13 is a schematic view showing the delivery cam surface 70 when the delivery amount is small. 12 and 13 show a cylindrical surface around the central axis including the pay-out cam surface 70 in the circumferential direction in order to show the positional relationship between the dial cam member 50 and the rail cam member 60. 12 and 13, the upper side is the rear side of the mechanical pencil 1.

Referring to FIG. 12, the dial cam member 50 is aligned with the rail cam member 60 so that the first bottom surface 63a of the rail cam 61 and the first cam bottom surface 51a of the dial cam 51 are aligned in the radial direction. In other words, the fitting protrusion 50d of the dial cam member 50 and the fitting recess 60b of the rail cam member 60 are arranged so that the first bottom surface 63a of the rail cam 61 and the first cam bottom surface 51a of the dial cam 51 are aligned in the radial direction. Is configured to correspond. The first cam bottom surface 51a of the dial cam 51 is on the same plane as the first bottom surface 63a of the rail cam 61 or is arranged slightly behind the first bottom surface 63a. Therefore, the first cam bottom surface 51 a of the dial cam 51 or the first bottom surface 63 a of the recess 63, the second bottom surface 63 b of the recess 63, and the annular cam surface 62 form the feeding cam surface 70. The height (difference) of the step 71 (drop) in the axial direction in the recess 63 on the feeding cam surface 70 is referred to as step height H. In FIG. 12, the step height H is the distance between the annular cam surface 62 of the rail cam 61 and the first cam bottom surface 51 a of the dial cam member 50 or the first bottom surface 63 a of the recess 63.

Referring to FIG. 13, the dial cam member 50 is aligned with the rail cam member 60 such that the first bottom surface 63a of the rail cam 61 and the third cam bottom surface 51c of the dial cam 51 are aligned in the radial direction. The rear end cam surface 51d of the dial cam 51 is substantially flush with the annular cam surface 62 of the rail cam 61. Therefore, the third cam bottom surface 51c of the dial cam 51, the rear end cam surface 51d, and the annular cam surface 62 form the payout cam surface 70. In FIG. 13, the step height H is the distance between the annular cam surface 62 of the rail cam 61 and the third cam bottom surface 51c of the dial cam member 50.

Similarly, the dial cam member 50 can be aligned with the rail cam member 60 so that the first bottom surface 63a of the rail cam 61 and the second cam bottom surface 51b of the dial cam 51 are aligned in the radial direction. In this case, the second cam bottom surface 51b of the dial cam 51, the second bottom surface 63b of the recess 63, and the annular cam surface 62 form the feeding cam surface 70. At this time, the step height H is the distance between the annular cam surface 62 of the rail cam 61 and the second cam bottom surface 51b of the dial cam member 50.

Similarly, the dial cam member 50 can be aligned with the rail cam member 60 so that the first bottom surface 63a of the rail cam 61 and the rear end cam surface 51d of the dial cam 51 are aligned in the radial direction. In this case, the rear end cam surface 51d of the dial cam 51 and the annular cam surface 62 form the payout cam surface 70. At this time, since the rear end cam surface 51d of the dial cam 51 is substantially flush with the annular cam surface 62 of the rail cam 61, the step height H is zero.

The rotor 40 of the rotary drive mechanism 30 gradually drives the slider 9 to rotate based on the cushion operation of the writing core 7. That is, when the tip portion 9a of the slider 9 is seen first, the slider 9 rotates clockwise around the central axis. By this rotational movement, the contactor 9c of the slider 9 moves in the circumferential direction in cooperation with the feeding cam surface 70. The relationship between the contactor 9c and the feeding cam surface 70 and the feeding of the writing core 7 will be described with reference to FIG.

FIG. 14 is a schematic diagram showing the relationship between the feeding cam surface 70 and the movement of the tip of the abutment member 9c. FIG. 14 shows the positional relationship between the feeding cam surface 70 and the contactor 9c. Therefore, in comparison with the cylindrical surface around the central axis including the feeding cam surface 70 that is circumferentially expanded, the tip of the contactor 9c is The locus T of movement is shown. In FIG. 14, the upper side is the rear side of the mechanical pencil 1.

In FIG. 14, the state of the feeding cam surface 70 shown in FIG. 12 is taken as an example. In FIG. 14, the contactor 9c moves from left to right. More specifically, as described with reference to FIGS. 6 and 7, the rotor 40 rotates while moving back and forth between the upper cam forming member 41 and the lower cam forming member 42 along the cam surface. .. Therefore, the tip of the abutment member 9c follows the locus T shown by the arrow in FIG.

First, the contactor 9c moves along the annular cam surface 62 of the feeding cam surface 70. Then, the contactor 9c is pressed by the urging force of the cam contact spring 18, falls into the recess 63, and moves forward until it contacts the first cam bottom surface 51a of the dial cam 51. That is, the slider 9 moves forward from the annular cam surface 62 by the step height H of the step 71. At this time, the holding chuck 10 arranged inside the slider 9 also moves forward, so that the writing core 7 held by the holding chuck 10 is pulled out from the ball chuck 11 and relatively stepped from the tip pipe 8. Only the height H is paid out. Therefore, the amount of the writing core 7 that is fed out, that is, the amount of feeding, is equal to the step height H.

Then, the abutment member 9c moves upward along the stepped concave portion 63, specifically, the second bottom surface 63b in accordance with the cushioning operation of the writing core 7, and thus moves to the annular cam surface 62 again while moving backward. Return. Next, the contactor 9c moves again along the annular cam surface 62 of the payout cam surface 70. By the above operation, the writing core 7 can be drawn from the tip pipe 8 every time the contactor 9c makes one turn along the payout cam surface 70. By repeating this operation, the writing core 7 is sequentially worn while the writing core 7 is worn along with the writing operation.

In short, in the lead-out mechanism, the contactor 9c moves along the annular cam surface 62 according to the rotation of the rotor 40, and the slider 9 advances when the contactor 9c falls into the step 71 of the payout cam surface 70. By the operation, the writing core 7 held by the holding chuck 10 is pulled out from the ball chuck 11. By utilizing the step 71 of the feeding cam surface 70 by the lead feeding mechanism, the rotational driving force of the rotor 40 in the rotary driving mechanism 30 can be converted into the feeding operation of the writing lead 7.

In the mechanical pencil described in Patent Document 4, since the cam surface is formed so as to rise along the circumferential direction, the contactor has a portion in a direction that resists the biasing force of the spring in addition to the frictional resistance. The force is also received, which becomes a factor that hinders the rotation of the rotary drive mechanism. On the other hand, in the mechanical pencil 1 of the above-described embodiment, since the annular cam surface 62 is formed perpendicularly to the axial direction, it is possible to receive the component force in the direction against the biasing force of the cam contact spring 18. Moreover, the rotation of the rotary drive mechanism 30 is not hindered thereby. Therefore, it is possible to realize a highly accurate and accurate payout operation of the writing core 7.

Further, the mechanical pencil 1 is configured to receive the rotational driving force of the rotor 40 in the rotational driving mechanism 30 so that the writing core 7 held by the ball chuck 11 is also rotationally driven. Therefore, it is possible to prevent the writing core 7 from being unevenly worn as the writing progresses, and as a result, it is possible to prevent the thickness of the drawn line and the thickness of the drawn line from greatly changing.

Further, in the payout amount adjusting mechanism, as described above, the step height H of the step 71 on the payout cam surface 70 is changed by simply rotating the dial cam member 50 and the rail cam member 60 relatively around the central axis. be able to. Therefore, the amount of feeding the writing lead 7 by the lead feeding mechanism can be adjusted more easily and accurately.

If the adjustment is made so that the degree of wear of the writing core 7 due to the difference in writing pressure depending on the user and the hardness of the writing core 7 to be used and the amount of the writing core 7 delivered are substantially the same, the writing operation will not be affected. The amount of protrusion of the writing core 7 from the tip pipe 8 can always be kept constant. As a result, with the mechanical pencil 1, it is possible to continue writing for a long time with a single knock operation. It is preferable to configure the dial cam 51 so that a step 71 having a step height H corresponding to a length that exceeds the normally assumed degree of wear of the writing core 7 is formed. Thereby, it is possible to set the feeding amount of the writing core 7 according to the preference of all users.

Specifically, in the above-described embodiment, the step height H of the step 71 is set to the annular cam surface 62, the first cam bottom surface 51a, the second cam bottom surface 51b, the third cam bottom surface 51c, or the rear end cam surface 51d. The distance between can be changed in four steps. For example, each step height H can be 0.15 mm, 0.10 mm, 0.05 mm or 0 mm. Therefore, for example, a user who has a high writing pressure and a large degree of wear of the writing core 7 adjusts the feeding amount adjusting mechanism so that the step height H becomes 0.15 mm, and the writing pressure is weak and the writing core is A user having a smaller degree of wear of 7 can adjust the feeding amount so that the step height H is 0.05 mm. Furthermore, a user who does not like to automatically extend the writing core 7 and who wants to extend the writing core 7 by performing a knocking operation by himself/herself should adjust the amount of extension so that the step height H becomes 0 mm (zero). You can

In the above-described embodiment, the dial cam 51 is formed stepwise by the three bottom surfaces provided in the recess of the rear end surface, but the dial cam 51 may be formed by two bottom surfaces or four or more bottom surfaces. Good. In this case, the feeding amount of the writing lead 7 by the lead feeding mechanism can be adjusted stepwise according to the number of bottom surfaces. Therefore, as the number of bottom surfaces is larger, the step height H can be set in a finer unit, for example, in the unit of 0.02 mm, and thus a finer feed amount can be adjusted. Further, only one bottom surface may be provided in the concave portion of the dial cam member 50 corresponding to the concave portion 63 in the feeding cam surface 70, and the dial cam member 50 may be configured to be movable in the axial direction with respect to the rail cam member 60. In this case, the step height H can be changed by moving the dial cam member 50 back and forth with respect to the rail cam member 60, that is, by moving the dial cam member 50 and the rail cam member 60 relatively back and forth. At this time, the step height H may be changed steplessly.

In the embodiment described above, the step is formed by one step, but it may be formed by a plurality of steps as long as the same height difference is obtained and the writing core 7 is extended. Further, the step may be a flat slope or a curved surface instead of the step as long as the same height difference is obtained and the writing core 7 is extended. The structure that forms the height difference on the annular cam surface is collectively referred to as "fall".

FIG. 15 is a schematic view showing another feeding cam surface 70. In FIG. 15, the upper side is the rear side of the mechanical pencil 1. In the above-described embodiment, the dial cam 51, which is a cam forming portion that cooperates with the recess 63 of the rail cam 61 to form the feeding cam surface 70, is formed in a stepped shape. However, as shown in FIG. 15, the dial cam 51 may be formed as a slope 51e along the circumferential direction, such as a slope or a spiral. In this case, by fitting the fitting protrusion 50d of the dial cam member 50 and the fitting recess 60b of the rail cam member 60, the dial cam member 50 and the rail cam member 60 are not rotated stepwise around the central axis, but are By making it rotatable in steps, the step height H of the step 71 can be changed steplessly. As a result, it is possible to make a finer adjustment of the delivery amount.

Although the dial cam member 50 is a cylindrical member as the first cam member in the above-described embodiment, it may be an annular member. Further, although the rail cam member 60 is an annular member as the second cam member, it may be a cylindrical member. The rail cam 61 may be provided on the first cam member, and the dial cam 51 may be provided on the second cam member. That is, the annular or tubular first cam member and the annular or tubular second cam member arranged radially outside the first cam member cooperate with each other to form the feeding cam surface. Good.

Therefore, the concave portion is formed in one of the first cam member and the second cam member, the cam forming portion is formed in the other of the first cam member and the second cam member, and the concave portion and the cam forming portion cooperate with each other. The cam surface may be configured. The step height of the step may be adjusted by relatively rotating the first cam member and the second cam member around the central axis. Further, the step height of the step may be adjusted by moving the first cam member and the second cam member back and forth relatively.

Although the feeding amount adjusting mechanism adjusts the feeding amount of the writing core 7 by the lead feeding mechanism, the feeding amount adjusting mechanism may be omitted. That is, a cam member having a payout cam surface having an annular cam surface perpendicular to the axial direction and a predetermined axial step provided on the annular cam surface may be attached to the barrel. Such a configuration can be realized by, for example, omitting the dial cam member 50 and providing only the rail cam member 60 in the above-described embodiment. In the embodiment described above, the annular cam surface 62 is a plane perpendicular to the axial direction, but it may be a cam surface having a slope shape or a spiral shape.

By the way, in the mechanical pencil described in Patent Document 4, the slider is biased forward by the spring in order to surely bring the contactor into contact with the cam surface. Therefore, as compared with a mechanical pencil having a rotary drive mechanism that does not have a lead-out mechanism, a higher writing pressure is required by the biasing force of the spring. Further, since the contactor is pressed against the cam surface by the spring, frictional resistance is generated when the slider is rotated by the rotation drive mechanism. Therefore, the rotation of the rotary drive mechanism may be hindered. Further, since the cam surface is formed so as to rise along the circumferential direction, in addition to the frictional resistance, the component force in the direction against the urging force of the spring becomes a factor that hinders the rotation of the rotary drive mechanism.

On the other hand, in the mechanical pencil 1, the lead-out mechanism is configured so as not to hinder the rotation of the rotation drive mechanism 30, which will be described in detail below.

In the mechanical pencil 1, as described above, the rear end of the cam contact spring 18 is attached to the flange 12a of the relay member 12, and the front end of the cam contact spring 18 is the inner wall of the rear end of the slider 9. Is attached to. The relay member 12 connected to the rotor 40 transmits the rotational movement of the rotor 40 in the rotary drive mechanism 30 to the ball chuck 11 holding the writing core 7, but to the slider 9. Do not communicate directly. That is, the slider 9 is arranged outside the front end portion of the relay member 12, but is not directly connected to the relay member 12. Instead, the rotation driving force is transmitted from the rotor 40 to the slider 9 in the rotation driving mechanism 30 via the cam contact spring 18.

Specifically, the cam contact spring 18 functions to bring the contactor 9c into contact with the cam surface by urging the slider 9 forward, and also functions as a torsion spring (torsion spring). Therefore, when the relay member 12 connected to the rotor 40 rotates, if there is no resistance or a small resistance when the slider 9 rotates around the central axis, the slider 9 also rotates following the rotation of the relay member 12. .. On the other hand, when the relay member 12 connected to the rotor 40 rotates and the resistance is large when the slider 9 rotates about the central axis, the slider 9 does not rotate and the cam contact spring 18 receives elastic energy in the twisting direction. accumulate. Specifically, in the locus T of FIG. 14, in the region M immediately after the contactor 9c accompanies the rearward movement in the stepped recess 63, that is, in the region M after the second bottom surface 63b is climbed up. The frictional force due to the frictional resistance between the child 9c and the feeding cam surface 70 is maximized.

First, when the writing pressure is released, the contactor 9c contacts the second bottom surface 63b at the point M1 by the urging force of the cam contact spring 18. At this time, the rotation drive mechanism 30 is in a state between FIG. 6(C) and FIG. 7(D).

Next, the rotation drive mechanism 30 transitions to the state of FIG. 7E (or FIG. 6A), and the rotor 40 rotates. At this time, the slider 9 moves backward by the height of the second bottom surface 63b, so that the cam contact spring 18 is compressed by the height of the second bottom surface 63b. When the cam contact spring 18 is compressed, the contactor 9c is pressed against the second bottom surface 63b with a stronger force as a reaction force of the urging force of the cam contact spring 18. Therefore, the frictional force between the contactor 9c and the second bottom surface 63b, that is, the dynamic frictional force and the static frictional force is increased. Therefore, even if the rotary drive mechanism 30 transits to the state of FIG. 7E, the contactor 9c does not move from the point M1. In other words, the slider 9 does not rotate, and elastic energy in the torsion direction is accumulated in the cam contact spring 18.

Next, when the next writing pressure is applied, the state transitions from the state of FIG. 6(A) to the state of FIG. 6(B). At this time, since the relay member 12 moves rearward via the writing core 7, the cam contact spring 18 connected to the relay member 12 relatively expands, and the contactor 9c with respect to the second bottom surface 63b. The urging force of the cam abutment spring 18 that is pressed by pressing is reduced. At that moment, the torque of twisting back due to the release of the accumulated elastic energy of the cam contact spring 18 exceeds the maximum static frictional force between the contactor 9c and the second bottom surface 63b to rotate the contactor 9c. .. As a result, the contactor 9c slides in the area M of the second bottom surface 63b against the frictional force and reaches the point M2. As a result, the phase of rotation of the slider 9 again coincides with the phase of rotation of the rotor 40, and the contactor 9c returns to the motion of following the locus T along the cam surface of the rotary drive mechanism 30.

Here, suppose that the behavior of the contactor in the region M is applied to the mechanical pencil described in Patent Document 4 and the slider having the contactor is directly connected via the relay member. When the writing pressure is released and the abutment element abuts the second bottom surface at the M1 point by the urging force of the cam abutment spring, the dynamic contact force and the static friction force increase, so that the abutment element can slide to the M2 point. Can not. Therefore, the rotation of the rotary drive mechanism connected to the slider is hindered, and the writing core cannot be rotated sufficiently. Further, in the mechanical pencil described in Patent Document 4, the cam surface corresponding to the annular cam surface 62 in the mechanical pencil 1 of the above-described embodiment is a cam surface that rises along the circumferential direction. Therefore, since the contactor moves on the cam surface while compressing the cam contact spring, the dynamic frictional force and the static frictional force are further increased between the contactor and the cam surface, and the rotary drive mechanism. Rotation is more hindered.

In order to reduce the dynamic frictional force and static frictional force between the contactor and the cam surface, it is possible to use a coil spring having a smaller spring constant as the cam contacting spring and reduce the urging force of the cam contacting spring. Conceivable. However, when a cam contact spring with a small biasing force is used, the rotation of the rotary drive mechanism is not obstructed, but the force for feeding the writing lead in the lead feeding mechanism is weakened. As a result, there is a possibility that the writing core may not be fed out, so it is necessary to use a coil spring having a certain degree of spring constant.

On the other hand, in the mechanical pencil 1 of the above-described embodiment, a coil spring having a spring constant capable of obtaining the force that extends the writing core 7 or a force greater than that can be used as the cam contact spring 18. Therefore, although the mechanical pencil 1 is configured so as not to hinder the rotation of the rotary drive mechanism 30, it is possible to realize a highly accurate operation of feeding the writing core 7 with high accuracy. Further, since the annular cam surface 62 is formed perpendicularly to the axial direction, no component force in the direction against the biasing force of the cam contact spring 18 is received, and the rotation of the rotary drive mechanism 30 is changed. Is not hindered by.

In short, in the mechanical pencil described in Patent Document 4, the rotational driving force is transmitted from the rotor to the slider via the rigid body, whereas in the mechanical pencil 1 of the above-described embodiment, the rotor 40 is used. The rotational driving force is transmitted from the slider to the slider 9 via the cam contact spring 18 which is a coil spring, that is, via the elastic member. Therefore, as described above, when the dynamic friction force and the static friction force increase, the elastic energy is accumulated in the elastic member, and thereafter, when the dynamic friction force and the static friction force are reduced, the elastic energy accumulated in the elastic member can be released. it can. As a result, the slider 9 and the contactor 9c can be rotationally moved at appropriate timing without impeding the rotational movement of the rotor 40 of the rotary drive mechanism 30.

Any structure and material can be adopted as the elastic member that transmits the rotational driving force from the rotor 40 to the slider 9 as long as elastic energy in the twisting direction can be accumulated. Therefore, the elastic member may be, for example, a tubular elastomer other than the torsion spring.

1 Mechanical Pencil 2 Front Axis 3 Rear Axis 4 Tip Member 5 Inner Cylinder 6 Axis Cylinder 7 Writing Core 8 Tip Pipe 9 Slider 9c Abutment 10 Holding Chuck 11 Ball Chuck 12 Relay Member 13 Chuck 14 Chuck Body 15 Chuck Holding Part 16 Ball 17 Coil Spring 18 Cam Abutment Spring 19 Core Case 20 Knock Rod 21 Coil Spring 22 Rubber 23 Knock Cover 30 Rotation Drive Mechanism 31 Shaft Spring 40 Rotor 40a First Cam Surface 40b Second Cam Surface 41 Upper Cam Forming Member 41a First fixed cam surface 42 Lower cam forming member 42a Second fixed cam surface 43 Cylinder member 44 Torque canceller 45 Cushion spring 50 Dial cam member 50a Grip portion 50b Small diameter portion 50c Flange portion 50d Fitting protrusion 51 Dial cam 51a First cam bottom surface 51b Second cam bottom surface 51c Third cam bottom surface 51d Rear end cam surface 60 Rail cam member 60a Adjustment recess 60b Fitting recess 60c Circumferential wall 61 Rail cam 62 Annular cam surface 63 Recess 63a First bottom surface 63b Second bottom surface 70 Cam surface 71 Step (drop) )
80 O-ring

Claims (4)

A ball chuck that allows the writing core to move forward and prevents it from moving backward,
The rotor has a rotor and is driven to rotate in one direction in response to an axial backward movement by writing pressure received by a writing core held by the ball chuck and an axial forward movement by releasing writing pressure. A rotary drive mechanism,
An annular cam surface, and a payout cam surface having a drop in the axial direction provided on the annular cam surface,
A slider that has a contact chuck that contacts the delivery cam surface and a writing chuck that holds a writing core, and that rotates by receiving the rotational driving force of the rotor;
The writing core held by the holding chuck by the forward movement of the slider when the contactor moves along the annular cam surface according to the rotation of the rotor and the contactor falls into the head. Is configured to be pulled out from the ball chuck,
A mechanical pencil characterized in that the rotational driving force is transmitted from the rotor to the slider through an elastic member. The mechanical pencil according to claim 1, wherein the elastic member is a torsion spring. The mechanical pencil according to claim 1, wherein the annular cam surface is formed perpendicular to the axial direction. The mechanical pencil according to any one of claims 1 to 3, wherein the ball chuck is configured to rotate when the ball chuck is rotated by receiving the rotational driving force of the rotor.

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