Sharp pencil

Abstract

To provide a mechanical pencil including a new feed mechanism.SOLUTION: A mechanical pencil 1 includes: a holding chuck 9 which holds a writing lead 8; a chuck unit 11 which allows forward movement of the wiring lead 8 and prevents rearward movement; and a first operation part which moves the chuck unit 11 forward through a rotation operation around a center axis.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a mechanical pencil.

Background Art

[0002] There is known a mechanical pencil having a ball chuck and a knock operation part provided at the rear end part or the outer peripheral surface thereof, and in which a refill is fed out by knocking the knock operation part. The mechanical pencil further includes a slider, and it is possible to feed out the refill also by operating the slider (Patent Document 1). In the knock operation, the ball chuck advances together with the refill by pressing the knock operation part forward, and then the ball chuck retreats by releasing the pressing. When the ball chuck retreats, the refill remains held by the holding chuck, and as a result, the refill is fed out.

[0003] The slider holds the holding chuck and is arranged to be movable back and forth while being biased forward in front of the ball chuck. When the slider is moved backward, the refill gripped by the ball chuck does not retreat and only the holding chuck retreats. Then, when the slider advances to return to its original position, the refill advances together with the forward movement of the holding chuck, and the refill is fed out.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, the amount of the refill extended by the knock operation of the knock operation unit is always constant. The amount of extension by one knock operation is customarily set to around 0.5 mm. When writing, the preference for the protruding amount of the refill from the tip pipe disposed at the tip of the mechanical pencil varies among users who write. For example, in the case of a user who prefers to write with the protruding amount being about 1.2 mm, when two knock operations are performed from the state where the refill is retracted into the tip pipe, the protruding amount becomes 1.0 mm and the refill feels short. When one more knock operation is performed for a total of three knock operations, the protruding amount becomes 1.5 mm and the refill feels long. In this case, the user is forced to perform an operation of retracting the refill that protrudes too much into the tip pipe by a minute amount.

[0006] Also, regardless of the user's preference for the protruding amount, in the case of a relatively thin refill such as a refill with a core diameter of 0.3 mm, if the protruding amount from the tip pipe is short, frequent knock operations must be performed, while if the protruding amount from the tip pipe is long, the refill is likely to break. Therefore, in the case of a thin core diameter, the customary extension amount of 0.5 mm may be too large and not appropriate.

[0007] Therefore, it is desirable to have a mechanical pencil capable of performing at least two extension operations, an extension operation capable of large extension and an extension operation capable of small extension, like the coarse adjustment screw and the fine adjustment screw of a microscope. Thereby, for example, when pulling out the next refill from the core case when the refill runs out, an extension operation with a large extension amount can be performed. Also, by switching to an extension operation with a small extension amount before reaching the preferred protruding amount, it becomes possible to adjust the protruding amount without performing an operation of retracting the refill that protrudes too much.

[0008] Patent Document 1 discloses that the amount of extension of the refill can be freely adjusted. However, since the amount of extension per time can be freely adjusted, there is a risk that the amount of extension may change unintentionally. Also, once the amount of extension is adjusted, it is difficult to readjust to the same amount of extension again.

[0009] An object of the present invention is to provide a sharp pencil having a novel feeding mechanism.

Means for Solving the Problems

[0010] According to one aspect of the present invention, there is provided a sharp pencil comprising: a holding chuck for holding a writing core; a ball chuck that allows the writing core to advance and prevents it from retreating; and a first operation portion that advances the ball chuck by a rotational operation around a central axis.

[0011] A first cam surface may be provided on an end surface of the first operation portion, a second cam surface that advances together with the ball chuck may be provided, and the first cam surface and the second cam surface may cooperate with each other with the rotational operation to advance the ball chuck. At least one protrusion may be provided on each of the first cam surface and the second cam surface, and with the rotational operation, the protrusion on the first cam surface and the protrusion on the second cam surface may abut against each other to advance the ball chuck. The ball chuck may be advanced by a sliding operation of the first operation portion forward. The first operation portion may be disposed at a central portion in the axial direction of the sharp pencil. The first operation portion may be a cylindrical member.

Advantages of the Invention

[0012] According to an aspect of the present invention, there is a common advantage of providing a sharp pencil having a novel feeding mechanism.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Throughout the drawings, common reference numerals are assigned to corresponding components.

[0015] Figure 1 is a side view of the Sharp pencil 1, Figure 2 is a longitudinal sectional view of the Sharp pencil 1 of Figure 1, and Figure 3 is a longitudinal sectional view of the first half of the Sharp pencil 1 of Figure 1.

[0016] The sharp pencil 1 has a front shaft 2, a rear shaft 3, a connecting member 4 connecting the front shaft 2 and the rear shaft 3, and a tip member 5 screwed onto the inner peripheral surface of the front end portion of the front shaft 2. On the front half portion of the outer peripheral surface of the front shaft 2, a gripping portion 2a composed of a plurality of grooves is formed as an anti-slip measure when gripping the sharp pencil 1. The connecting member 4 is a cylindrical member. The front end portion of the connecting member 4 fits into the inner peripheral surface of the rear end portion of the front shaft 2, and the rear end portion of the connecting member 4 fits into the inner peripheral surface of the front end portion of the rear shaft 3. The front shaft 2, the rear shaft 3, and the connecting member 4 constitute a shaft cylinder 6. Note that the shaft cylinder 6 may also be referred to including the tip member 5. A tip pipe 7 is attached to the tip of the tip member 5, and the writing core 8 protrudes from the tip pipe 7. Behind the tip pipe 7, a rubber holding chuck 9 having a through hole formed in the center is disposed. The through hole of the holding chuck 9 is in sliding contact with the outer peripheral surface of the writing core 8 and is configured to temporarily hold the writing core 8. In this specification, in the axial direction of the sharp pencil 1, the tip pipe 7 side is defined as the "front" side, and the side opposite to the tip pipe 7 side is defined as the "rear" side.

[0017] Inside the shaft cylinder 6, particularly inside the front shaft 2, a sliding body 10 that is movably arranged back and forth and formed in a cylindrical shape and a chuck unit 11 that grips the writing core 8 are arranged. The chuck unit 11 is, for example, a ball chuck. The chuck unit 11 has a relay member 12 formed in a cylindrical shape, a fastener 13 formed in a cylindrical shape, a chuck main body portion 14 disposed inside the fastener 13, a knock transmission cylindrical body 15 formed in a cylindrical shape, a plurality of balls 16, an annular stopper member 17, and a chuck spring 18.

[0018] The relay member 12 is fitted by press-fitting onto the outer peripheral surface of the rear end portion of the fastener 13. The relay member 12 and the fastener 13 are arranged within the shaft cylinder 6 so as to be integrally movable back and forth. On the inner peripheral surface of the front end portion of the fastener 13, a tapered surface that expands forward is formed. The chuck main body portion 14 has a through-hole for the writing core 8 formed along the central axis, and the front end portion of the chuck main body portion 14 is divided into a plurality along the axial direction. The knock transmission cylindrical body 15 is arranged separately from the chuck main body portion 14 in the initial state where no operation is performed, and does not hold the chuck main body portion 14. The plurality of balls 16 are arranged between the outer surface of the chuck main body portion 14 and the tapered surface of the fastener 13. The chuck main body portion 14 is movable in the axial direction with respect to the fastener 13.

[0019] When writing pressure is applied to the writing core 8, the chuck main body portion 14 abuts against the tapered surface in the cylindrical fastener 13 together with the balls 16, so that the writing core 8 is gripped by the chuck main body portion 14. Thereby, the backward movement of the writing core 8 is prevented. On the other hand, when a force to pull out the writing core 8 forward acts, since the chuck main body portion 14 is not affected by the action of the fastener 13, the writing core 8 can be pulled out forward without resistance. That is, the chuck unit 11 is configured to allow the forward movement of the writing core 8 and prevent the backward movement. Note that the stopper member 17 is fitted into the inner peripheral surface of the front end portion of the fastener 13 to prevent the balls 16 from falling off.

[0020] A chuck spring 18 is arranged so as to surround the chuck main body portion 14. The rear end portion of the chuck spring 18 is fitted to the outer surface of the chuck main body portion 14, and the front end portion of the chuck spring 18 is supported by a stepped portion formed on the inner peripheral surface of the fastener 13. The chuck spring 18 biases the chuck main body portion 14 backward with respect to the fastener 13, and as a result, the chuck unit 11 can maintain the state of gripping the writing core 8.

[0021] At the rear end of the cylindrical body 15 for knock transmission, the front end of the core case 19 is fitted. The core case 19 is formed in a cylindrical shape, and the writing core 8 is accommodated inside. A cylindrical joint member 20 is fitted so as to cover the fitting portion of the knock transmission cylindrical body 15 and the core case 19 and the front end of the core case 19.

[0022] At the rear end of the shaft cylinder 6, a knock member 21 is provided so as to be movable back and forth with respect to the shaft cylinder 6. The knock member 21 is biased rearward by a knock spring 22. Inside the rear end of the knock member 21, an eraser rubber 23 is detachably attached as an erasing member. A knock cover 24 is detachably attached to the outer peripheral surface of the rear end of the knock member 21 to protect the eraser rubber 23 from dirt and the like. The knock member 21 is fitted through a joint member 19a provided at the rear end of the core case 19. Inside the shaft cylinder 6 in front of the slider 10, a spring 25 is arranged as a coil spring surrounding the relay member 12. Inside the connecting member 4, an O-ring 26 made of an elastic material is arranged.

[0023] At the central portion in the axial direction of the mechanical pencil 1, that is, at the central portion of the shaft cylinder 6, a first operating mechanism 30 is arranged. The first operating mechanism 30 has a first operating portion 31 which is arranged on the outer peripheral surface of the connecting member 4 and is a cylindrical member, an annular recess 33 formed on the outer peripheral surface of the rear end of the slider 10, and an annular member 32 arranged in the recess 33. The annular member 32 is arranged in front of the first operating portion 31.

[0024] Note that the first operating mechanism 30, specifically the first operating portion 31, may be arranged not at the central portion of the shaft cylinder 6 but closer to the front or the rear. The first operating portion 31 may be a substantially cylindrical member with a C-shaped cross section instead of a cylindrical member.

[0025] Referring to FIG. 3, a flange portion 12a is formed at the central portion in the axial direction of the relay member 12. The front end of the spring 25 is arranged on the inner wall of the shaft cylinder 6, that is, the inner wall of the tip member 5, and the rear end of the spring 25 is arranged near the flange portion 12a of the relay member 12.

[0026] The sliding body 10 is integrally biased rearward by the contact between the rear end surface of the flange portion 12a of the relay member 12 biased rearward by the spring 25 and the front end surface of the sliding body 10. In other words, the sliding body 10 is biased rearward via the relay member 12. The backward movement of the sliding body 10 and the relay member 12 is restricted by the O-ring 26. Two annular protrusions 10a are provided on the outer peripheral surface of the sliding body 10 at intervals in the axial direction (Fig. 2). By providing the annular protrusions 10a on the sliding body 10, the protrusions 10a are in sliding contact with the inner peripheral surface of the shaft cylinder 6 when the sliding body 10 moves, and the frictional resistance and sliding contact noise with the inner peripheral surface of the shaft cylinder 6 are reduced. Instead of the annular protrusions, a plurality of protrusions provided at equal intervals along the circumferential direction, rib-shaped protrusions provided at equal intervals along the circumferential direction and extending in the axial direction, etc. may be used. That is, as long as the contact area between the inner peripheral surface of the shaft cylinder 6 and the outer peripheral surface of the sliding body 10 can be reduced and the frictional resistance can be reduced, protrusions of any shape may be provided on the outer peripheral surface of the sliding body 10. Also, instead of providing protrusions on the outer peripheral surface of the sliding body 10, similar protrusions may be provided on the inner peripheral surface of the shaft cylinder 6.

[0027] Fig. 4 is a perspective view of the first operation portion 31 and the annular member 32. A plurality of first protrusions 31a are provided on the front end surface of the first operation portion 31 at equal intervals along the circumferential direction, and the front end surface constitutes a first cam surface. A plurality of longitudinal grooves 31b are provided on the outer peripheral surface of the first operation portion 31, extending in the axial direction and arranged at equal intervals along the circumferential direction. Two second protrusions 32a are provided on the rear end surface of the annular member 32, and the rear end surface constitutes a second cam surface. The second cam surface advances together with the ball chuck as will be described later. Two locking protrusions 32b protruding radially inward are provided on the inner peripheral surface of the annular member 32. The first protrusions 31a and the second protrusions 32a are substantially hemispherical in shape.

[0028] With reference to FIGS. 5 and 6, the feeding out of the refill 8 by the sliding operation of the first operation portion 31 will be described. FIG. 5 is a longitudinal sectional view of the mechanical pencil 1 showing the first operation mechanism 30 in a normal state, and FIG. 6 is a longitudinal sectional view of the mechanical pencil 1 showing the first operation mechanism 30 during the sliding operation. The locking projection 32b of the annular member 32 protrudes into the recess 33 of the slider 10. As described above, since the slider 10 is biased rearward, the locking projection 32b of the annular member 32 engages with the inner surface of the recess 33 of the slider 10, and the annular member 32 is also biased rearward. Further, the first operation portion 31 is biased rearward via the annular member 32, and the rearward movement of the first operation portion 31 is restricted by the front end surface of the rear shaft 3.

[0029] The sliding operation is performed by sliding and advancing the first operation portion 31 with the thumb while gripping the mechanical pencil 1, for example, from the state shown in FIG. 5. Specifically, when the first operation portion 31 advances, the slider 10 advances via the annular member 32. Next, the relay member 12 advances against the biasing force of the spring 25 via the flange portion 12a that is in contact with the front end surface of the slider 10. At this time, the clamp 13 that fits with the relay member 12, and further, the chuck main body portion 14, the ball 16, the stopper member 17, and the chuck spring 18 advance integrally. In short, in the chuck unit 11, the members other than the knock transmission cylindrical body 15 advance integrally.

[0030] The refill 8 is held by the holding chuck 9 in front of the chuck unit 11. However, as described above, the chuck unit 11 is configured to prevent the refill 8 from retracting. Therefore, the refill 8 gripped by the chuck main body portion 14 advances together with the chuck unit 11. The advancement of the chuck unit 11 stops when the front end surface of the annular member 32 abuts against the rear end surface of the front shaft 2 (FIG. 6). Note that the advancement of the chuck unit 11 may stop when the front end surface of the chuck unit 11, that is, the front end surface of the stopper member 17, abuts against the stepped portion 5a provided on the inner peripheral surface of the tip member 5.

[0031] When the slide operation is released from the state shown in Fig. 6, the relay member 12 and the slider 10 via the flange portion 12a are retracted by the biasing force of the spring 25. At this time, in the chuck unit 11, members other than the cylindrical body 15 for knock transmission are retracted integrally. As described above, since the chuck unit 11 is configured to allow the forward movement of the refill 8, the refill 8 is held by the holding chuck 9 without being retracted together with the chuck unit 11. Therefore, the refill 8 is relatively pulled out from the chuck unit 11, that is, from the chuck main body portion 14. The retraction of the chuck unit 11 stops when the rear end face of the first operation portion 31 abuts against the front end face of the rear shaft 3 (Fig. 5). Note that the retraction of the chuck unit 11 may be stopped by the slider 10 colliding with the O-ring 26 via the relay member 12.

[0032] From the above, the refill 8 is fed out by the amount of the stroke in the axial direction of the chuck unit 11, that is, the distance D1 (Fig. 5) which is the clearance between the front end face of the annular member 32 and the front shaft 2, by the slide operation of the first operation portion 31. In other words, each time the slide operation is repeated, the refill 8 can be fed out by a predetermined amount. Since the cylindrical body 15 for knock transmission is arranged separately from the chuck main body portion 14, it does not move within the shaft cylinder 6 during the slide operation. Note that since the slide operation is an operation of pressing the first operation portion 31 forward, it may be referred to as a knock operation.

[0033] With reference to Fig. 7, the feeding out of the refill 8 by the knock operation will be described. Fig. 7 is a longitudinal sectional view of the mechanical pencil 1 showing the knock operation step by step. The knock operation is performed by pressing the second operation portion of the mechanical pencil 1, that is, the knock cover 24, the eraser 23 or the knock member 21, forward against the biasing force of the knock spring 22. The second operation portion constitutes a second operation mechanism. Note that the second operation portion may be provided on the outer peripheral surface instead of the rear end portion of the mechanical pencil.

[0034] When the second operation part is pressed by a knocking operation from the state shown in FIG. 3, as shown in FIG. 7(A), the core case 19 fitted to the knock member 21 advances. By the advancement of the core case 19, the knock transmission cylindrical body 15 and the joint member 20 fitted to the front end part of the core case 19 advance. By the advancement of the joint member 20, a protrusion 20a at the rear end part of the joint member 20 and a protrusion 12c at the rear end part of the relay member 12 engage with each other.

[0035] When the second operation part is further pressed, as shown in FIG. 7(B), with the relay member 12 and the joint member 20 engaged, the entire chuck unit 11 advances against the biasing force of the spring 25. Therefore, when the front end part of the mechanical pencil 1 faces downward, the slider 10 advances together with the relay member 12 due to gravity. The advancement of the chuck unit 11 stops when the front end face of the chuck unit 11, that is, the front end face of the stopper member 17, abuts against a stepped part 5a provided on the inner peripheral surface of the tip member 5. At this time, the chuck spring 18 is not compressed.

[0036] Next, when the second operation part is further pressed, as shown in FIG. 7(C), the protrusion 20a at the rear end of the joint member 20 gets over the protrusion 12c at the rear end of the relay member 12 and the engagement is released, and the joint member 20 advances with respect to the relay member 12. Due to the advancement of the joint member 20, the knock transmission cylindrical body 15 advances and abuts against the chuck main body part 14. Further, the chuck main body part 14 holding the refill 8 and the knock transmission cylindrical body 15 advance with respect to the fastener 13 against the biasing force of the chuck spring 18. At this time, the knock transmission cylindrical body 15 deeply receives the rear end part of the chuck main body part 14 inside. Here, a tapered surface 15a that expands forward is formed on the inner peripheral surface of the knock transmission cylindrical body 15. When the rear end part of the chuck main body part 14 is pressed against the tapered surface 15a of the knock transmission cylindrical body 15 due to the advancement of the knock transmission cylindrical body 15, the rear end part of the chuck main body part 14 moves radially inward, while the front end part of the chuck main body part 14 expands radially outward and the refill 8 is released. The advancement of the knock transmission cylindrical body 15 stops when the front end surface of the joint member 20 fitted to the knock transmission cylindrical body 15 abuts against a stepped part 12b provided on the inner peripheral surface of the relay member 12.

[0037] Next, when the pressing of the second operation part by the knock operation is released, due to the biasing force of the knock spring 22, the knock member 21 retreats and returns to its original position. Along with this, the chuck main body part 14 retreats due to the biasing force of the chuck spring 18, and the entire chuck unit 11 retreats due to the biasing force of the spring 25. As described above, since the chuck unit 11 is configured to allow the advancement of the refill 8, the refill 8 is held by the holding chuck 9 without retreating together with the chuck unit 11. Therefore, the refill 8 is pulled out from the chuck unit 11, that is, from the chuck main body part 14 by a distance D2 relatively. The retreat of the chuck unit 11 stops when the sliding body 10 collides with the O-ring 26 via the relay member 12.

[0038] As described above, the refill 8 is fed out by the amount of the stroke in the axial direction of the chuck unit 11, that is, by the distance D2, by the knock operation of the second operation unit. As shown in FIG. 7(C), in a state where the refill 8 is released from the chuck main body portion 14, the refill 8 fed out from the tip pipe 7 can be pushed back with a fingertip or the like.

[0039] With reference to FIGS. 8 and 9, the feeding out of the refill 8 by the rotation operation of the first operation unit 31 will be described. FIG. 8 is a diagram for explaining the rotation operation of the first operation unit 31. FIG. 8(A) shows the positional relationship between the first operation unit 31 and the annular member 32 in the normal state, and FIG. 8(B) shows the positional relationship between the first operation unit 31 and the annular member 32 during the rotation operation. FIG. 9 is a longitudinal sectional view of the sharp pencil 1 showing the first operation mechanism 30 during the rotation operation of the first operation unit 31.

[0040] The first operation unit 31 is rotatably arranged around the central axis of the sharp pencil 1 with respect to the outer peripheral surface of the connection member 4. As described above, since a plurality of longitudinal grooves 31b are formed on the outer peripheral surface of the first operation unit 31, the first operation unit 31 can be surely rotated without the finger slipping. In the normal state shown in FIG. 8(A), the second protrusion 32a of the annular member 32 is arranged between the plurality of first protrusions 31a of the opposing first operation unit 31. FIG. 5 corresponds to the longitudinal sectional view in FIG. 8(A).

[0041] The rotation operation is performed, for example, by rotating the first operation unit 31 with the thumb while holding the sharp pencil 1. Specifically, when the first operation unit 31 is rotated with respect to the shaft cylinder 6, that is, with respect to the annular member 32, from the state shown in FIG. 8(A), the first protrusion 31a of the first operation unit 31 and the second protrusion 32a of the annular member 32 abut, and the annular member 32 moves forward. That is, the annular member 32 moves forward by a distance D3 corresponding to the smaller of the heights of the first protrusion 31a of the first operation unit 31 or the second protrusion 32a of the annular member 32 (FIG. 8(B)). When the annular member 32 moves forward, the sliding body 10 moves forward in the same manner as in the above-described sliding operation, and as a result, the chuck unit 11 also moves forward by the distance D3.

[0042] When the first operation unit 31 is further rotated from the state shown in FIG. 8(B), the engagement between the first protrusion 31a of the first operation unit 31 and the second protrusion 32a of the annular member 32 is released, and due to the biasing force of the spring 25, the annular member 32 retreats together with the relay member 12 and the slider 10 via the flange portion 12a. At this time, in the chuck unit 11, members other than the cylindrical body 15 for knock transmission retreat integrally. As described above, since the chuck unit 11 is configured to allow the advancement of the refill 8, the refill 8 is held by the holding chuck 9 without retreating together with the chuck unit 11. Therefore, the refill 8 is relatively drawn out from the chuck unit 11, that is, from the chuck main body portion 14. The retreat of the chuck unit 11 stops when the first protrusion 31a of the first operation unit 31 or the second protrusion 32a of the annular member 32 abuts against the opposing surface (FIG. 8(A)).

[0043] From the above, the refill 8 is fed out by the amount of the stroke in the axial direction of the chuck unit 11, that is, the distance D3 (FIG. 8(B)), by the rotation operation of the first operation unit 31. By repeating the engagement and disengagement of the first protrusion 31a of the first operation unit 31 and the second protrusion 32a of the annular member 32 by the rotation operation, the refill 8 can be fed out by a predetermined amount. Since the cylindrical body 15 for knock transmission is arranged separately from the chuck main body portion 14, it does not move within the shaft cylinder 6 during the rotation operation.

[0044] For the rotation operation, the first operation unit 31 may be rotated in the same direction, or the first operation unit 31 may be swung within a predetermined angle. When swinging at a predetermined angle, for example, a torsion spring may be connected to the first operation unit 31 so that after swinging at the predetermined angle, it returns to the original position by the elastic force of the torsion spring. In this case, it is sufficient to have at least one first protrusion 31a and at least one second protrusion 32a. According to the rotation operation, the rotational movement of the first operation unit 31 can be converted into the linear movement of the chuck unit 11. The front and rear arrangements of the first operation unit 31 and the annular member 32 may be exchanged.

[0045] FIG. 10 is a diagram for explaining the rotation operation of another first operation unit 41. The first protrusion 31a of the first operation unit 31 and the second protrusion 32a of the annular member 32 described above were spherical in shape, but the first protrusion 41a of the first operation unit 41 and the second protrusion 42a of the annular member 42 shown in FIG. 10 are in the shape of a saw blade with a slope formed on one side along the circumferential direction. Therefore, for example, in FIG. 10, the first operation unit 41 can be rotated in the direction of arrow R, and the annular member 42 can be moved back and forth. On the other hand, in FIG. 10, when the first operation unit 41 is rotated in the direction opposite to arrow R, the first protrusion 41a of the first operation unit 41 and the second protrusion 42a of the annular member 42 are locked to each other, and the first operation unit 41 cannot be rotated. Thereby, it becomes possible to regulate the rotation direction of the first operation unit 41 in which the refill 8 can be fed out to one side.

[0046] FIG. 11 is a side view of another sharp pencil 100. The sharp pencil 100 is different only in the operating mechanism disposed in the central portion in the axial direction of the sharp pencil 100 as compared with the sharp pencil 1 described above. That is, the sharp pencil 100 has a third operation mechanism 130 instead of the first operation mechanism 30 of the sharp pencil 1.

[0047] FIG. 12 is a longitudinal sectional view of the sharp pencil 100 showing the third operation mechanism 130. FIG. 12(A) shows the third operation mechanism 130 in a normal state, and FIG. 12(B) shows the third operation mechanism 130 during a click operation. The third operation mechanism 130 includes a third operation unit 131 that is movably provided in a direction orthogonal to the central axis of the sharp pencil 100 and has an operation protrusion 131a that protrudes radially outward from the shaft cylinder 6, and a dome spring 132 disposed in the shaft cylinder 6. A protruding pressing portion 131b is provided on the third operation unit 131 on the side opposite to the operation protrusion 131a. Further, in the third operation unit 131, a first inclined surface 131c is formed on the side surface between the operation protrusion 131a and the pressing portion 131b. Opposite to the first inclined surface 131c of the third operation unit 131, a second inclined surface 10b is formed on the side surface of the sliding body 10.

[0048] The click operation is performed, for example, by pressing the third operation portion 131 against the shaft cylinder 6 with the thumb while gripping the Sharp pencil 1. Specifically, it is performed by pressing the operation protrusion 131a of the third operation portion 131 against the shaft cylinder 6 from the state shown in FIG. 12(A). When the third operation portion 131 moves in a direction orthogonal to the central axis of the Sharp pencil 100, the dome spring 132 is deformed by the pressing portion 131b (FIG. 12(B)). At this time, due to the movement of the third operation portion 131, the first inclined surface 131c of the third operation portion 131 and the second inclined surface 10b of the sliding body 10 cooperate, and the sliding body 10 advances by a distance D4. As a result, the chuck unit 11 also advances by the distance D4. Due to the deformation of the dome spring 132, the user can obtain a click feeling.

[0049] When the click operation is released from the state shown in FIG. 12(B), the relay member 12 and the sliding body 10 via the flange portion 12a are retracted by the biasing force of the spring 25. Due to the retraction of the sliding body 10, the first inclined surface 131c of the third operation portion 131 and the second inclined surface 10b of the sliding body 10 cooperate to return the third operation portion 131 to its original position. Also, as described above, the chuck unit 11 is retracted by the biasing force of the spring 25, and the refill 8 is relatively pulled out from the chuck unit 11.

[0050] From the above, the refill 8 is fed out by the amount of stroke in the axial direction of the chuck unit 11, that is, by the distance D4 (FIG. 12(B)), by the click operation of the third operation portion 131. Since the click operation is an operation of pressing the third operation portion 131 against the shaft cylinder 6, it may be referred to as a knock operation.

[0051] As described above, according to the Sharp pencil, the lead 8 can be fed out by the slide operation or rotation operation of the first operation unit 31 or the click operation of the third operation unit 131 as the first operation, and the knock operation on the rear end of the Sharp pencil as the second operation. By the first operation, the ball chuck advances by a distance D1, D3 or D4 corresponding to the first distance, and the lead 8 is fed out by that amount. By the second operation, the ball chuck advances by a distance D2 as the second distance, and the lead 8 is fed out by that amount.

[0052] According to the Sharp pencil 1, the second distance is set to be larger than the first distance. As described above, the distance D1 can be adjusted by adjusting the clearance between the front end face of the annular member 32 and the front shaft 2. Also, the distance D3 can be adjusted by adjusting the height of the first protrusion 31a or the second protrusion 32a. Further, the distance D4 can be adjusted by adjusting the angles of the first inclined surface 131c and the second inclined surface 10b.

[0053] In short, the above-described Sharp pencil enables at least two knock operations with different lead feed amounts. Furthermore, since the lead feed amount is predetermined at the time of product shipment, it cannot be changed by the user. Therefore, by switching the operation, the expected lead feed amount can always be obtained.

[0054] The second operation is a normal knocking operation, and the second distance, i.e., the amount of the refill 8 fed out by the second operation, is customarily set to 0.5 mm. On the other hand, the first distance, i.e., the amount of the refill 8 fed out by the first operation, is preferably 0.05 mm or more and 0.4 mm or less, more preferably 0.1 mm or more and 0.3 mm or less, and particularly preferably 0.2 mm. If the fed-out amount is less than 0.05 mm, fine adjustment of the fed-out amount becomes possible, but the fed-out amount is too small and many feeding operations are required. On the other hand, if it is more than 0.4 mm, there is no difference from the fed-out amount by the knocking operation, and the significance of making the fed-out amounts different disappears. Therefore, a fed-out amount of 0.2 mm is particularly preferable. For example, when the first distance is 0.3 mm, by combining multiples of 0.3 mm and multiples of 0.5 mm, the protruding amount of the refill 8 according to the preferences of many users can be obtained.

[0055] Furthermore, regarding the first operation portion 31 of the mechanical pencil 1, when the slide operation is the first operation and the rotation operation is the third operation, the distance D3 by which the ball chuck advances by the third operation is defined as the third distance. At this time, as described above, the second distance may be set to be larger than the first distance, and the third distance may be set to be smaller than the first distance. Specifically, the amount of the refill 8 fed out by the slide operation (distance D1) may be set to be smaller than the amount of the refill 8 fed out by the knocking operation (distance D2), and the amount of the refill 8 fed out by the rotation operation (D3) may be set to be smaller than the amount of the refill 8 fed out by the slide operation (distance D1). Thereby, finer adjustment of the fed-out amount becomes possible. The rotation operation may be the first operation and the slide operation may be the second operation.

[0056] As described above, it is possible to provide a Sharp pencil equipped with a novel feeding mechanism. In the Sharp pencil provided with the first operating mechanism 30 described above, only one or both of a slide operation and a rotation operation may be enabled. In the Sharp pencil provided with the first operating mechanism 30, when both a slide operation and a rotation operation are enabled, the feeding amount of the writing core 8 by the slide operation may be set to 0.5 mm, and the feeding amount of the writing core 8 by the rotation operation may be set to 0.3 mm.

Explanation of Signs

[0057] 1 Sharp pencil 2 Front shaft 3 Rear shaft 4 Connecting member 5 Tip member 6 Shaft cylinder 7 Tip pipe 8 Writing core 9 Holding chuck 10 Sliding body 11 Chuck unit 12 Relay member 13 Fastener 14 Chuck main body 15 Cylindrical body for knock transmission 16 Ball 17 Stopper member 18 Chuck spring 19 Core case 20 Joint member 21 Knock member 22 Knock spring 23 Eraser 24 Knock cover 25 Spring 26 O-ring 30 First operating mechanism 31 First operating part 31a First protrusion 31b Longitudinal groove 32 Annular member 32a Second protrusion 32b Locking protrusion 33 Recess

Claims

1. a holding chuck for holding a refill, a ball chuck that allows the refill to advance and prevents it from retracting, and a first operating portion that advances the ball chuck by a rotational operation about a central axis; A sharp pencil, characterized in that the ball chuck is advanced by a forward sliding operation of the first operating portion.

2. A first cam surface is provided on an end surface of the first operating portion, a second cam surface that advances together with the ball chuck is provided, and the first cam surface and the second cam surface cooperate with each other along with the rotational operation to advance the ball chuck. The sharp pencil according to Claim 1.

3. At least one protrusion is provided on each of the first cam surface and the second cam surface, and along with the rotational operation, the protrusion on the first cam surface and the protrusion on the second cam surface abut against each other to advance the ball chuck. The sharp pencil according to Claim 2.

4. The sharp pencil according to any one of Claims 1 to 3, wherein the first operating portion is disposed at a central portion in the axial direction of the sharp pencil.

5. The sharp pencil according to any one of Claims 1 to 4, wherein the first operating portion is a cylindrical member.

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