Mechanical pencil

Abstract

To provide a mechanical pencil which enables two knock operations in which feed lengths are different from each other.SOLUTION: A mechanical pencil 1 includes: a holding chuck 9 which holds a writing lead 8; a chuck unit 11 which is configured to allow forward movement of the wiring lead 8 and prevent rearward movement; a first operation part or a third operation part which is configured to move the chuck unit 11 forward only by a first distance through a first operation; and a second operation part which is configured to move the chuck unit 11 forward only by a second distance through a second operation. The first distance is shorter than the second distance.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] A mechanical pencil has a ball chuck, and the lead is advanced by knocking a knock operation part provided on the rear end or outer periphery. A mechanical pencil further has a slider, and the lead can also be advanced by operating the slider (Patent Document 1). In the knock operation, the ball chuck advances together with the lead by pressing the knock operation part forward, and then the ball chuck retreats by releasing the pressure. When the ball chuck retreats, the lead remains held by the holding chuck, and as a result, the lead is advanced.

[0003] The slider holds the retaining chuck and is arranged in front of the ball chuck so that it can move back and forth while being biased forward. When the slider is moved backward, the writing lead held by the ball chuck moves back, but only the retaining chuck moves back. Next, when the slider moves forward to return to its original position, the writing lead moves forward together with the retaining chuck, and the writing lead is dispensed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Publication number 2-026701 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the amount of lead advanced by the knock operation of the knock operation part is always constant. The amount of lead advanced by one knock operation is customarily set to around 0.5 mm. When writing, the preference for the amount of lead protruding from the tip pipe located at the tip of the mechanical pencil varies depending on the user who writes. For example, in the case of a user who prefers writing with the amount of lead protruding being about 1.2 mm, if the user performs two knock operations from a state in which the lead is retracted into the tip pipe, the amount of lead protruding becomes 1.0 mm, and the user feels that the lead is short. If the user performs one more knock operation for a total of three knock operations, the amount of lead protruding becomes 1.5 mm, and the user feels that the lead is long. In this case, the user is forced to return the lead that has protruded too far back into the tip pipe by a small amount.

[0006] Furthermore, regardless of the user's preference for the amount of protrusion, in the case of a relatively thin writing lead, for example a lead with a diameter of 0.3 mm, if the amount of protrusion from the tip pipe is short, the knock operation must be performed frequently, whereas if the amount of protrusion from the tip pipe is long, the writing lead is prone to breaking. Therefore, for a thin lead diameter, the conventional amount of protrusion of 0.5 mm may be too large and inappropriate.

[0007] Therefore, it is desirable to have a mechanical pencil that can perform at least two extension operations, one for large extension and one for small extension, like the coarse and fine screws of a microscope. This allows a large amount of extension to be performed when pulling the next lead from the lead case when the lead runs out. Also, by switching to a small amount of extension before the desired amount of extension is reached, the amount of extension can be adjusted without having to return the lead that has extended too far.

[0008] Patent Document 1 discloses that the amount of lead that is advanced can be freely adjusted, but because the amount of lead advanced per stroke can be freely adjusted, there is a risk that the amount of lead advanced may change unintentionally. Also, once the amount of lead advanced has been adjusted, it is difficult to adjust it back to the same amount.

[0009] An object of the present invention is to provide a mechanical pencil capable of performing at least two knock operations with different advancement amounts. [Means for solving the problem]

[0010] According to one aspect of the present invention, there is provided a mechanical pencil comprising: a retaining chuck for holding a writing lead; a ball chuck configured to allow the writing lead to move forward and prevent it from moving backward; a first operating part or a third operating part configured to advance the ball chuck a first distance by a first operation; and a second operating part configured to advance the ball chuck a second distance by a second operation, wherein the first distance is smaller than the second distance.

[0011] The first operation may be either a slide operation of sliding the first operating part provided on the outer peripheral surface of the mechanical pencil forward or a rotation operation of rotating the first operating part around the central axis of the mechanical pencil, and the second operation may be a knock operation of pressing the second operating part provided on the rear end or the outer peripheral surface of the mechanical pencil forward. The first operation may be a slide operation of sliding the first operating part provided on the outer peripheral surface of the mechanical pencil forward to advance the ball chuck by the first distance, and the first operating part may be configured to advance the ball chuck by a third distance by a third operation, the third operation may be a rotation operation of rotating the first operating part around the central axis of the mechanical pencil, and the second operation may be a knock operation of pressing the second operating part provided on the rear end or the outer peripheral surface of the mechanical pencil forward. The third distance may be smaller than the first distance. A first cam surface may be provided on an end surface of the first operating part, and a second cam surface may be provided that advances together with the ball chuck, and the first cam surface and the second cam surface may cooperate with each other in accordance with the rotation operation to advance the ball chuck. The first operating part may be disposed in a central portion in the axial direction of the mechanical pencil. The first operating part may be a cylindrical member. The first distance may be 0.05 mm or more and 0.4 mm or less. Effect of the Invention

[0012] According to the aspects of the present invention, a common effect is achieved in that a mechanical pencil capable of at least two knock operations with different advancement amounts is provided. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a side view of a mechanical pencil. [Diagram 2] FIG. 2 is a vertical cross-sectional view of the mechanical pencil of FIG. [Diagram 3] FIG. 3 is a vertical cross-sectional view of the front half of the mechanical pencil of FIG. [Figure 4]FIG. 4 is a perspective view of the first operating portion and the annular member. [Diagram 5] FIG. 5 is a vertical cross-sectional view of the mechanical pencil showing the first operating mechanism in a normal state. [Figure 6] FIG. 6 is a vertical cross-sectional view of the mechanical pencil showing the first operating mechanism during a sliding operation. [Figure 7] FIG. 7 is a vertical cross-sectional view of a mechanical pencil showing a stepwise process of knocking. [Figure 8] FIG. 8 is a diagram illustrating the rotation operation of the first operating unit. [Figure 9] FIG. 9 is a vertical cross-sectional view of the mechanical pencil showing the first operating mechanism during rotational operation of the first operating part. [Figure 10] FIG. 10 is a diagram illustrating a rotation operation of another first operating unit. [Figure 11] FIG. 11 is a side view of another mechanical pencil. [Figure 12] FIG. 12 is a vertical cross-sectional view of the mechanical pencil showing the third operating mechanism during a click operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Corresponding components are designated by common reference numerals throughout the drawings.

[0015] 1 is a side view of a mechanical pencil 1, FIG. 2 is a vertical cross-sectional view of the mechanical pencil 1 of FIG. 1, and FIG. 3 is a vertical cross-sectional view of the front half of the mechanical pencil 1 of FIG.

[0016] The mechanical pencil 1 has a front shaft 2, a rear shaft 3, a connecting member 4 that connects the front shaft 2 and the rear shaft 3, and a tip member 5 that screws into the inner peripheral surface of the front end of the front shaft 2. A gripping portion 2a consisting of a plurality of grooves is formed in the front half of the outer peripheral surface of the front shaft 2 as a slip-proofing when the mechanical pencil 1 is held. The connecting member 4 is a cylindrical member, and the front end of the connecting member 4 fits into the inner peripheral surface of the rear end of the front shaft 2, and the rear end of the connecting member 4 fits into the inner peripheral surface of the front end of the rear shaft 3. The front shaft 2, the rear shaft 3, and the connecting member 4 form a shaft tube 6. The tip member 5 may also be referred to as the shaft tube 6. A tip pipe 7 is attached to the tip of the tip member 5, and a writing core 8 protrudes from the tip pipe 7. A rubber holding chuck 9 with a through hole formed in the center is arranged behind the tip pipe 7. The through hole of the holding chuck 9 is configured to come into sliding contact with the outer peripheral surface of the writing lead 8 and temporarily hold the writing lead 8. In this specification, in the axial direction of the mechanical pencil 1, the tip pipe 7 side is defined as the "front" side, and the opposite side to the tip pipe 7 side is defined as the "rear" side.

[0017] Inside the barrel 6, particularly the front barrel 2, there are disposed a cylindrically formed sliding body 10 that is arranged to be movable back and forth, and a chuck unit 11 that grips the writing lead 8. The chuck unit 11 is, for example, a ball chuck. The chuck unit 11 has a cylindrically formed relay member 12, a cylindrically formed fastener 13, a chuck main body 14 arranged inside the fastener 13, a cylindrically formed knock transmitting cylinder 15, a plurality of balls 16, an annular stopper member 17, and a chuck spring 18.

[0018] The relay member 12 is fitted to the outer peripheral surface of the rear end of the fastener 13 by press-fitting. The relay member 12 and the fastener 13 are arranged in the barrel 6 so as to be movable back and forth as a unit. A tapered surface that expands toward the front is formed on the inner peripheral surface of the front end of the fastener 13. The chuck body 14 has a through hole for the writing core 8 formed along the central axis, and the front end of the chuck body 14 is divided into multiple parts along the axial direction. The knock transmission cylinder 15 is arranged separately from the chuck body 14 in the initial state in which no operation is performed, and does not hold the chuck body 14. The multiple balls 16 are arranged between the outer surface of the chuck body 14 and the tapered surface of the fastener 13. The chuck body 14 is movable in the axial direction relative to the fastener 13.

[0019] When writing pressure is applied to the writing core 8, the chuck body 14 and the ball 16 come into contact with the tapered surface inside the cylindrical fastener 13, so that the writing core 8 is gripped by the chuck body 14. This prevents the writing core 8 from retracting. On the other hand, when a force is applied to pull the writing core 8 forward, the chuck body 14 is not acted upon by the fastener 13, so the writing core 8 can be pulled forward without resistance. In other words, the chuck unit 11 is configured to allow the writing core 8 to advance and prevent it from retracting. The stopper member 17 is fitted into the inner circumferential surface of the front end of the fastener 13 to prevent the ball 16 from falling out.

[0020] The chuck spring 18 is disposed so as to surround the chuck body 14. The rear end of the chuck spring 18 fits into the outer surface of the chuck body 14, and the front end of the chuck spring 18 is supported by a step formed on the inner peripheral surface of the fastener 13. The chuck spring 18 biases the chuck body 14 rearward against the fastener 13, and as a result, the chuck unit 11 can maintain a state in which it grips the writing lead 8.

[0021] The front end of the lead case 19 is fitted into the rear end of the knock transmitting cylinder 15. The lead case 19 is formed in a cylindrical shape and houses the writing lead 8 inside. A cylindrically formed coupling member 20 is fitted in such a way as to cover the fitting portion between the knock transmitting cylinder 15 and the lead case 19 and the front end of the lead case 19.

[0022] A knock member 21 is provided at the rear end of the barrel 6 so as to be movable back and forth relative to the barrel 6. The knock member 21 is urged rearward by a knock spring 22. An eraser 23 is removably attached inside the rear end of the knock member 21 as an erasing member. A knock cover 24 is removably attached to the outer circumferential surface of the rear end of the knock member 21 to protect the eraser 23 from dirt and the like. The knock member 21 is fitted through a coupling member 19a provided at the rear end of the lead case 19. A spring 25 is provided inside the barrel 6 in front of the sliding body 10 as a coil spring surrounding the relay member 12. An O-ring 26 made of an elastic material is provided inside the connection member 4.

[0023] A first operating mechanism 30 is disposed in the central portion of the mechanical pencil 1 in the axial direction, i.e., in the central portion of the barrel 6. The first operating mechanism 30 has a first operating part 31 that is disposed on the outer circumferential surface of the connecting member 4 and is a cylindrical member, a ring-shaped recess 33 formed on the outer circumferential surface of the rear end of the sliding body 10, and an annular member 32 disposed in the recess 33. The ring-shaped member 32 is disposed in front of the first operating part 31.

[0024] The first operating mechanism 30, specifically the first operating part 31, may be disposed toward the front or rear of the barrel 6, rather than in the center. The first operating part 31 may be a substantially cylindrical member having a C-shaped cross section, rather than a cylindrical member.

[0025] 3, a flange portion 12a is formed in the central portion in the axial direction of the relay member 12. The front end portion of the spring 25 is disposed on the inner wall of the barrel 6, i.e., the inner wall of the tip member 5, and the rear end portion of the spring 25 is disposed in the vicinity of the flange portion 12a of the relay member 12.

[0026] The sliding body 10 is urged backward as a whole by the abutment between the rear end surface of the flange portion 12a of the relay member 12, which is urged backward by the spring 25, and the front end surface of the sliding body 10. In other words, the sliding body 10 is urged backward via the relay member 12. The retraction of the sliding body 10 and the relay member 12 is regulated by the O-ring 26. Two annular protrusions 10a are provided on the outer circumferential surface of the sliding body 10 and arranged spaced apart in the axial direction (FIG. 2). By providing the annular protrusions 10a on the sliding body 10, the protrusions 10a come into sliding contact with the inner circumferential surface of the shaft tube 6 when the sliding body 10 moves, and the frictional resistance and sliding noise with the inner circumferential surface of the shaft tube 6 are reduced. Note that, instead of the annular protrusions, a plurality of protrusions provided at equal intervals along the circumferential direction, rib-like protrusions provided at equal intervals along the circumferential direction and extending in the axial direction, or the like may be used. That is, as long as it is possible to reduce the contact area between the inner peripheral surface of the barrel 6 and the outer peripheral surface of the slide body 10 and thereby reduce the frictional resistance, protrusions of any shape may be provided on the outer peripheral surface of the slide body 10. Moreover, instead of providing protrusions on the outer peripheral surface of the slide body 10, similar protrusions may be provided on the inner peripheral surface of the barrel 6.

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

[0028] With reference to Figs. 5 and 6, the feeding of the writing lead 8 by the sliding operation of the first operating part 31 will be described. Fig. 5 is a vertical cross-sectional view of the mechanical pencil 1 showing the first operating mechanism 30 in a normal state, and Fig. 6 is a vertical cross-sectional view of the mechanical pencil 1 showing the first operating mechanism 30 during the sliding operation. The locking projection 32b of the annular member 32 protrudes into the recessed portion 33 of the sliding body 10. As described above, since the sliding body 10 is biased backward, the locking projection 32b of the annular member 32 is engaged with the inner surface of the recessed portion 33 of the sliding body 10, and the annular member 32 is also biased backward. In addition, the first operating part 31 is biased backward via the annular member 32, and the rearward movement of the first operating part 31 is restricted by the front end surface of the rear shaft 3.

[0029] The sliding operation is performed by, for example, sliding the first operating part 31 with the thumb while holding the mechanical pencil 1 from the state shown in Fig. 5 to move it forward. Specifically, the forward movement of the first operating part 31 moves the sliding body 10 forward via the annular member 32. Next, the relay member 12 moves forward against the biasing force of the spring 25 via the flange portion 12a that abuts against the front end surface of the sliding body 10. At this time, the fastener 13 that fits with the relay member 12, as well as the chuck main body 14, the ball 16, the stopper member 17, and the chuck spring 18, move forward integrally. In short, in the chuck unit 11, the members other than the knock transmitting cylinder 15 move forward integrally.

[0030] The writing core 8 is held by the holding chuck 9 in front of the chuck unit 11, and as described above, the chuck unit 11 is configured to prevent the writing core 8 from retracting. Therefore, the writing core 8 gripped by the chuck main body 14 advances together with the chuck unit 11. The advancement of the chuck unit 11 is stopped when the front end face of the annular member 32 abuts against the rear end face of the front shaft 2 (FIG. 6). The advancement of the chuck unit 11 may also be stopped when the front end face of the chuck unit 11, i.e., the front end face of the stopper member 17, abuts against a step 5a provided on the inner peripheral surface of the tip member 5.

[0031] When the sliding operation is released from the state shown in FIG. 6, the relay member 12 and the sliding body 10 via the flange portion 12a are moved backward by the biasing force of the spring 25. At this time, the members of the chuck unit 11 other than the knock transmitting cylinder 15 are moved backward as a unit. As described above, the chuck unit 11 is configured to allow the writing core 8 to advance, so the writing core 8 is held by the holding chuck 9 without moving backward together with the chuck unit 11. Therefore, the writing core 8 is relatively pulled out from the chuck unit 11, that is, from the chuck main body portion 14. The backward movement of the chuck unit 11 is stopped by the rear end surface of the first operating portion 31 coming into contact with the front end surface of the rear shaft 3 (FIG. 5). The backward movement of the chuck unit 11 may be stopped by the sliding body 10 colliding with the O-ring 26 via the relay member 12.

[0032] As described above, by sliding the first operating part 31, the writing lead 8 is advanced by an amount equivalent to the stroke in the axial direction of the chuck unit 11, i.e., the distance D1 (FIG. 5) which is the clearance between the front end face of the annular member 32 and the front shaft 2. In other words, each time the sliding operation is repeated, the writing lead 8 can be advanced by a predetermined amount. The knock transmitting cylinder 15 is disposed separately from the chuck main body 14, and therefore does not move within the shaft tube 6 during the sliding operation. Note that the sliding operation may also be referred to as a knocking operation, as it is an operation of pressing the first operating part 31 forward.

[0033] With reference to FIG. 7, the extension of the writing lead 8 by the knock operation will be described. FIG. 7 is a vertical cross-sectional view of the mechanical pencil 1 showing the knock operation in stages. The knock operation is performed by pressing the second operating part of the mechanical pencil 1, i.e., the knock cover 24, the eraser 23 or the knock member 21, forward against the biasing force of the knock spring 22. The second operating part constitutes a second operating mechanism. The second operating part may be provided on the outer circumferential surface of the mechanical pencil instead of on the rear end thereof.

[0034] When the second operating part is pressed by a knock operation from the state shown in Fig. 3, the lead case 19 that fits into the knock member 21 moves forward, as shown in Fig. 7(A). The advancement of the lead case 19 advances the knock transmitting cylinder 15 and the coupling member 20 that fit into the front end of the lead case 19. The advancement of the coupling member 20 engages the protrusion 20a at the rear end of the coupling member 20 with the protrusion 12c at the rear end of the relay member 12.

[0035] When the second operating part is further pressed, as shown in Fig. 7(B), the entire chuck unit 11 advances against the biasing force of the spring 25 in a state in which the relay member 12 and the joint member 20 are engaged. Therefore, when the front end of the mechanical pencil 1 faces downward, the sliding body 10 advances together with the relay member 12 due to gravity. The advancement of the chuck unit 11 is stopped when the front end face of the chuck unit 11, i.e., the front end face of the stopper member 17, abuts against the step portion 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 operating part is further pressed, as shown in FIG. 7(C), the projection 20a at the rear end of the coupling member 20 passes over the projection 12c at the rear end of the relay member 12, disengages the coupling member 20, and moves forward relative to the relay member 12. The forward movement of the coupling member 20 causes the knock transmitting cylinder 15 to move forward and come into contact with the chuck body 14. Furthermore, the chuck body 14 gripping the writing lead 8 and the knock transmitting cylinder 15 move forward relative to the fastener 13 against the biasing force of the chuck spring 18. At this time, the knock transmitting cylinder 15 receives the rear end of the chuck body 14 deep inside. Here, a tapered surface 15a expanding toward the front is formed on the inner peripheral surface of the knock transmitting cylinder 15. When the rear end of the chuck body 14 is pressed against the tapered surface 15a of the knock transmitting cylinder 15 by the forward movement of the knock transmitting cylinder 15, the rear end of the chuck body 14 moves radially inward while the front end of the chuck body 14 expands radially outward, releasing the writing lead 8. The forward movement of the knock transmitting cylinder 15 is stopped when the front end face of the coupling member 20 that fits into the knock transmitting cylinder 15 abuts against a step 12b provided on the inner peripheral surface of the relay member 12.

[0037] Next, when the pressure on the second operation part by the knock operation is released, the knock member 21 retreats and returns to its original position due to the biasing force of the knock spring 22. Accordingly, the chuck main body 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, the chuck unit 11 is configured to allow the writing lead 8 to advance, so the writing lead 8 is held by the holding chuck 9 without retreating together with the chuck unit 11. Therefore, the writing lead 8 is pulled out from the chuck unit 11, i.e., from the chuck main body 14, by a distance D2. The retreat of the chuck unit 11 is stopped by the collision of the sliding body 10 with the O-ring 26 via the relay member 12.

[0038] As described above, the writing lead 8 is advanced by the stroke in the axial direction of the chuck unit 11, i.e., the distance D2, by the knock operation of the second operating part. As shown in Fig. 7(C), when the writing lead 8 is released from the chuck main body 14, the writing lead 8 advanced from the tip pipe 7 can be pushed back with a fingertip or the like.

[0039] With reference to Figures 8 and 9, the extension of the writing lead 8 by rotating the first operating unit 31 will be described. Figure 8 is a diagram illustrating the rotating operation of the first operating unit 31. Figure 8(A) shows the positional relationship between the first operating unit 31 and the annular member 32 in the normal state, and Figure 8(B) shows the positional relationship between the first operating unit 31 and the annular member 32 during the rotating operation. Figure 9 is a vertical cross-sectional view of the mechanical pencil 1 showing the first operating mechanism 30 during the rotating operation of the first operating unit 31.

[0040] The first operating part 31 is arranged to be rotatable around the central axis of the mechanical pencil 1 with respect to the outer circumferential surface of the connecting member 4. As described above, since a plurality of vertical grooves 31b are formed on the outer circumferential surface of the first operating part 31, the first operating part 31 can be rotated reliably 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 operating part 31. FIG. 5 corresponds to the vertical cross-sectional view in FIG. 8(A).

[0041] The rotation operation is performed, for example, by rotating the first operating part 31 with the thumb while holding the mechanical pencil 1. Specifically, when the first operating part 31 is rotated relative to the shaft tube 6, i.e., the annular member 32, from the state shown in FIG. 8(A), the first protrusion 31a of the first operating part 31 and the second protrusion 32a of the annular member 32 come into abutment with each other, and the annular member 32 advances. That is, the annular member 32 advances by a distance D3 corresponding to the height of the smaller of the first protrusion 31a of the first operating part 31 or the second protrusion 32a of the annular member 32 (FIG. 8(B)). When the annular member 32 advances, the sliding body 10 advances, as in the case of the above-mentioned sliding operation, and as a result, the chuck unit 11 also advances by the distance D3.

[0042] When the first operating part 31 is further rotated from the state shown in FIG. 8(B), the first protrusion 31a of the first operating part 31 and the second protrusion 32a of the annular member 32 are released from the abutment, and the annular member 32 retreats together with the relay member 12 and the sliding body 10 via the flange portion 12a due to the biasing force of the spring 25. At this time, in the chuck unit 11, the members other than the knock transmitting cylinder 15 retreat as one body. As described above, since the chuck unit 11 is configured to allow the writing core 8 to advance, the writing core 8 does not retreat together with the chuck unit 11, but is held by the holding chuck 9. Therefore, the writing core 8 is relatively pulled out from the chuck unit 11, that is, from the chuck main body portion 14. The retreat of the chuck unit 11 is stopped by the first protrusion 31a of the first operating part 31 or the second protrusion 32a of the annular member 32 abutting against the opposing surface (FIG. 8(A)).

[0043] As described above, the writing lead 8 is advanced by the stroke in the axial direction of the chuck unit 11, i.e., by the distance D3 (FIG. 8(B)), by the rotation of the first operating part 31. The rotation repeatedly brings the first protrusion 31a of the first operating part 31 and the second protrusion 32a of the annular member 32 into and out of engagement with each other, thereby advancing the writing lead 8 by a predetermined amount. The knock transmitting cylinder 15 is disposed separately from the chuck main body 14, and therefore does not move within the barrel 6 during the rotation.

[0044] The rotation operation may rotate the first operating part 31 in the same direction, or may swing the first operating part 31 within a predetermined angle. When swinging the first operating part 31 at a predetermined angle, for example, a torsion spring may be connected to the first operating part 31, and the first operating part 31 may be returned to its original position by the elastic force of the torsion spring after swinging at the predetermined angle. In this case, it is sufficient to have at least one first protrusion 31a and at least one second protrusion 32a. By the rotation operation, the rotational motion of the first operating part 31 can be converted into the linear motion of the chuck unit 11. The front-rear arrangement of the first operating part 31 and the annular member 32 may be exchanged.

[0045] FIG. 10 is a diagram for explaining the rotation operation of another first operating part 41. The first protrusion 31a of the first operating part 31 and the second protrusion 32a of the annular member 32 described above are spherical in shape, but the first protrusion 41a of the first operating part 41 and the second protrusion 42a of the annular member 42 shown in FIG. 10 are sawtooth in shape with a slope formed on one side along the circumferential direction. Therefore, for example, in FIG. 10, the first operating part 41 can be rotated in the direction of the arrow R, and the annular member 42 can be moved back and forth. On the other hand, in FIG. 10, when the first operating part 41 is rotated in the direction opposite to the arrow R, the first protrusion 41a of the first operating part 41 and the second protrusion 42a of the annular member 42 are engaged with each other, and the first operating part 41 cannot be rotated. Thereby, it is possible to restrict the rotation direction of the first operating part 41, in which the writing core 8 can be advanced, to one side.

[0046] 11 is a side view of another mechanical pencil 100. The mechanical pencil 100 differs from the mechanical pencil 1 described above only in the operation mechanism disposed in the central portion in the axial direction of the mechanical pencil 100. That is, the mechanical pencil 100 has a third operation mechanism 130 instead of the first operation mechanism 30 of the mechanical pencil 1.

[0047] FIG. 12 is a vertical cross-sectional view of the mechanical 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 in a click operation. The third operation mechanism 130 has a third operation part 131 provided with an operation protrusion 131a that is provided movably in a direction perpendicular to the central axis of the mechanical pencil 100 and protrudes radially outward from the shaft tube 6, and a dome spring 132 arranged in the shaft tube 6. The third operation part 131 is provided with a protruding pressing part 131b on the opposite side to the operation protrusion 131a. In addition, in the third operation part 131, a first inclined surface 131c is formed on the side surface between the operation protrusion 131a and the pressing part 131b. Opposite to the first inclined surface 131c of the third operation part 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 operating part 131 against the barrel 6 with the thumb while holding the mechanical pencil 1. Specifically, the click operation is performed by pressing the operating protrusion 131a of the third operating part 131 against the barrel 6 from the state shown in FIG. 12(A). When the third operating part 131 moves in a direction perpendicular to the central axis of the mechanical pencil 100, the pressing part 131b deforms the dome spring 132 (FIG. 12(B)). At this time, the movement of the third operating part 131 causes the first inclined surface 131c of the third operating part 131 and the second inclined surface 10b of the sliding body 10 to cooperate with each other, and the sliding body 10 advances by a distance D4, and as a result, the chuck unit 11 also advances by the distance D4. The deformation of the dome spring 132 gives the user a clicking sensation.

[0049] 12(B), when the click operation is released, the relay member 12 and the sliding body 10 via the flange portion 12a are moved backward by the biasing force of the spring 25. By the movement of the sliding body 10 backward, the first inclined surface 131c of the third operation part 131 and the second inclined surface 10b of the sliding body 10 cooperate with each other to return the third operation part 131 to its original position. As described above, the chuck unit 11 is moved backward by the biasing force of the spring 25, and the writing lead 8 is relatively pulled out from the chuck unit 11.

[0050] As described above, the writing lead 8 is advanced by the stroke in the axial direction of the chuck unit 11, i.e., by the distance D4 (FIG. 12(B)), by the click operation of the third operating part 131. Note that the click operation may also be referred to as a knock operation, since it is an operation in which the third operating part 131 is pressed against the barrel 6.

[0051] As described above, with the mechanical pencil, the writing lead 8 can be advanced by a first operation, which is a sliding or rotating operation of the first operating part 31 or a clicking operation of the third operating part 131, and a second operation, which is a knocking operation of the rear end part of the mechanical pencil. The first operation causes the ball chuck to advance by a corresponding distance D1, distance D3 or distance D4 as a first distance, and the writing lead 8 is advanced by that amount, and the second operation causes the ball chuck to advance by a distance D2 as a second distance, and the writing lead 8 is advanced by that amount.

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

[0053] In short, the mechanical pencil described above is capable of at least two knocking operations with different amounts of advance. Furthermore, the amount of advance is preset at the time of product shipment and cannot be changed by the user. Therefore, by switching between operations, the expected amount of advance can always be obtained.

[0054] The second operation is a normal knock operation, and the second distance, i.e., the amount of lead 8 advanced by the second operation, is customarily set to 0.5 mm. On the other hand, the first distance, i.e., the amount of lead 8 advanced 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 amount of advance is less than 0.05 mm, fine adjustment of the amount of advance is possible, but the amount of advance is too small and many advance operations are required. On the other hand, if it is greater than 0.4 mm, there is no difference with the amount of advance by the knock operation, and there is no point in making the amount of advance different. Therefore, an amount of advance of 0.2 mm is particularly preferable. For example, if the first distance is 0.3 mm, by combining multiples of 0.3 mm and multiples of 0.5 mm, it is possible to obtain the amount of protrusion of the lead 8 that meets the preferences of many users.

[0055] Furthermore, for the first operating part 31 of the mechanical pencil 1, if 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 the third distance. At this time, as described above, the second distance may be set to be greater than the first distance, and the third distance may be set to be smaller than the first distance. Specifically, the amount of lead 8 advanced by the slide operation (distance D1) may be set smaller than the amount of lead 8 advanced by the knock operation (distance D2), and the amount of lead 8 advanced by the rotation operation (D3) may be set smaller than the amount of lead 8 advanced by the slide operation (distance D1). This allows for more fine adjustment of the amount of lead advanced. 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 mechanical pencil equipped with a novel extension mechanism. In a mechanical pencil equipped with the above-mentioned first operation mechanism 30, only one of a sliding operation and a rotating operation, or both, may be possible. In a mechanical pencil equipped with the first operation mechanism 30, when both a sliding operation and a rotating operation are possible, the amount of lead 8 extended by a sliding operation may be set to 0.5 mm, and the amount of lead 8 extended by a rotating operation may be set to 0.3 mm. [Explanation of symbols]

[0057] 1 mechanical pencil 2 front axle 3 rear axle 4 Connection parts 5 Tip member 6 shaft cylinder 7 Tip pipe 8 writing lead 9 Holding chuck 10 Slider 11 Chuck unit 12 Intermediate parts 13 Fasteners 14 Chuck body 15 Knock transmission cylinder 16 Ball 17 Stopper member 18 Chuck spring 19 Lead Case 20 Joint members 21 Knock parts 22 Knockspring 23 Eraser 24 Knock Cover 25 Spring 26 O-ring 30 First operating mechanism 31 1st operation section 31a 1st protrusion 31b Vertical groove 32 Annular member 32a 2nd protrusion 32b Locking protrusion 33 Recess

Claims

1. The pen includes a holding chuck for holding a writing lead, a chuck unit configured to allow the writing lead to move forward and prevent the writing lead to move backward, a first operation section or a third operation section configured to advance the chuck unit a first distance by a first operation to advance the writing lead, and a second operation section configured to advance the chuck unit a second distance by a second operation to advance the writing lead, The mechanical pencil, wherein the first distance is smaller than the second distance.

2. 2. The mechanical pencil according to claim 1, wherein the first operation is either a sliding operation for sliding the first operating part provided on the outer peripheral surface of the mechanical pencil forward or a rotating operation for rotating the first operating part around the central axis of the mechanical pencil, and the second operation is a knocking operation for pressing the second operating part provided on the rear end or the outer peripheral surface of the mechanical pencil forward.

3. the first operation is a slide operation in which the first operating part provided on the outer peripheral surface of the mechanical pencil is slid forward to advance the chuck unit by the first distance, The first operating part is configured to advance the chuck unit by a third distance by a third operation, and the third operation is a rotation operation that rotates the first operating part around a central axis of the mechanical pencil, The mechanical pencil according to claim 1 , wherein the second operation is a knock operation of pressing forward the second operating portion provided on a rear end or an outer peripheral surface of the mechanical pencil.

4. The mechanical pencil according to claim 3 , wherein the third distance is smaller than the first distance.

5. 5. The mechanical pencil according to claim 2, wherein a first cam surface is provided on an end surface of the first operating portion, and a second cam surface is provided which advances together with the chuck unit, and the first cam surface and the second cam surface cooperate with each other in association with the rotation operation to advance the chuck unit.

6. The mechanical pencil according to claim 1 , wherein the first operating portion is disposed at a central portion in an axial direction of the mechanical pencil.

7. The mechanical pencil according to claim 1 , wherein the first operating portion is a cylindrical member.

8. The mechanical pencil according to claim 1 , wherein the first distance is equal to or greater than 0.05 mm and equal to or less than 0.4 mm.

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