Propelling pencil

Abstract

A mechanical pencil is provided with: a barrel (5); a rotating member having a collet unit (10) capable of gripping and releasing the refill, and a slider having a holding portion, the rotating member partially protruding from the tip of the barrel; and a rotation drive mechanism (30) that has a rotating body (40) connected to the rotating member, and that drives the rotating body to rotate in one direction by receiving a backward movement in the axial direction caused by writing pressure received by the refill held by the chuck unit and a forward movement in the axial direction caused by release of the writing pressure. The rotating member is configured so as to rotate by receiving the rotational driving force of the rotating body, thereby causing the refill held by the chuck unit to rotate, and a viscous fluid (70) is applied between the inner surface of the tip portion of the barrel and the outer surface of the holding portion.

Description

Technical Field

[0001] This invention relates to mechanical pencils. Background Technology

[0002] A known mechanical pencil comprises: a barrel; a rotating member having a clamping unit and a sliding member, the clamping unit being capable of holding and releasing the lead; and a rotation drive mechanism having a rotating body, which receives a backward movement in the axial direction caused by writing pressure borne by the lead held by the clamping unit and a forward movement in the axial direction caused by the release of writing pressure, thereby driving the rotating body to rotate in one direction. The mechanical pencil is configured such that the clamping unit rotates under the rotational driving force of the rotating body, thereby rotating the lead (Patent Document 1).

[0003] Typically, in mechanical pencils with a rotating lead, a gap exists between the inner surface of the front end of the pencil barrel and the outer surface of the slider, based on manufacturing tolerances, to allow for the rotation and axial movement of the slider. However, due to this gap, some wobbling of the slider may occur radially, orthogonal to the central axis of the mechanical pencil. This radial wobbling of the slider during writing is sometimes noticed by the user as wobbling at the tip of the lead. Furthermore, due to this radial wobbling, the slider and the pencil barrel sometimes collide, producing an unpleasant clattering sound.

[0004] In the mechanical pencil described in Patent Document 1, multiple short fibers are implanted on the inner surface of the front end of the pencil barrel or the outer surface of the slider to mitigate wobbling. That is, multiple short fibers are used to mitigate the movement of the slider relative to the pencil barrel, preventing or buffering collisions between the slider and the pencil barrel.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-132843 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] In the mechanical pencil described in Patent Document 1, due to years or repeated use, the short fibers may wear down or fall off, resulting in a reduction in quantity. Furthermore, if the user has a habit of always holding the same position while writing, the short fibers in only specific areas may be repeatedly subjected to load, potentially causing uneven wear or reduction of the short fibers distributed throughout the circumference. If the short fibers decrease or wear down, the effect of mitigating wobbling also deteriorates.

[0010] The object of the present invention is to provide a mechanical pencil configured to mitigate radial wobble of the lead.

[0011] Solution for solving the problem

[0012] According to one aspect of the present invention, a mechanical pencil is provided, comprising: a barrel; a rotating member having a clamping unit capable of holding and releasing the lead and a sliding member having a holding portion, wherein a portion of the rotating member protrudes from the front end of the barrel; and a rotation drive mechanism having a rotating body connected to the rotating member, which receives a backward movement in the axial direction caused by writing pressure borne by the lead held by the clamping unit and a forward movement in the axial direction caused by the release of writing pressure, thereby driving the rotating body to rotate in one direction, configured such that the rotating member rotates by receiving the rotational driving force of the rotating body, thereby rotating the lead held by the clamping unit, and a viscous fluid is applied between the inner surface of the front end portion of the barrel and the outer surface of the holding portion.

[0013] Alternatively, the pen barrel may have a tip that includes the front end and is detachable from the pen barrel, configured such that when the tip is removed from the pen barrel, the retaining portion disengages from the rotating member together with the tip. Alternatively, the rotating member may also have a cylindrical sleeve that includes the retaining portion and is detachable from the sliding member. Alternatively, the front end of the sleeve may be tapered or have a smaller diameter compared to the rear end. Alternatively, an annular flange may be provided at the rear end of the sleeve. Alternatively, at least one recess may be provided on the front end face of the flange. Alternatively, a locking portion may be provided within the tip to lock the retraction of the retaining portion. Alternatively, the locking portion may be a separate component from the tip.

[0014] The effects of the invention

[0015] According to the technical solution of the present invention, a mechanical pencil is provided that is configured to mitigate radial wobble of the lead. Attached Figure Description

[0016] Figure 1 This is a longitudinal sectional view of the mechanical pencil according to the first embodiment of the present invention.

[0017] Figure 2 yes Figure 1 An enlarged cross-sectional view of the front end of a mechanical pencil.

[0018] Figure 3 yes Figure 1 An enlarged cross-sectional view of the central part of a mechanical pencil.

[0019] Figure 4 This is a schematic diagram illustrating the rotational drive of a rotating body in a rotary drive mechanism.

[0020] Figure 5 It continues Figure 4 A schematic diagram illustrating the rotational drive of a rotating body.

[0021] Figure 6 yes Figure 1 A three-dimensional diagram of the sleeve of a mechanical pencil.

[0022] Figure 7 yes Figure 6 The front view of the sleeve.

[0023] Figure 8 yes Figure 6 The longitudinal section view of the sleeve.

[0024] Figure 9 It is a three-dimensional diagram of another sleeve.

[0025] Figure 10 It is used to explain in stages. Figure 1 An enlarged cross-sectional view of the front end of the mechanical pencil's click mechanism.

[0026] Figure 11 yes Figure 1 A partially enlarged cross-sectional view of a mechanical pencil after the barrel has been removed.

[0027] Figure 12 This is a partial exploded perspective view of the mechanical pencil according to the second embodiment of the present invention.

[0028] Figure 13 yes Figure 11 An enlarged cross-sectional view of the front end of a mechanical pencil.

[0029] Figure 14 yes Figure 11 A partially enlarged cross-sectional view of a mechanical pencil after the tip component has been removed.

[0030] Figure 15 This is an enlarged cross-sectional view of the front end of the mechanical pencil according to the third embodiment of the present invention. Detailed Implementation

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In all the drawings, corresponding structural elements are labeled with common reference numerals.

[0032] Figure 1 This is a longitudinal sectional view of the mechanical pencil 1 according to the first embodiment of the present invention. Figure 2 yes Figure 1 An enlarged sectional view of the front end of the mechanical pencil 1.

[0033] The mechanical pencil 1 has a front barrel 2, a rear barrel 3 connected to the front barrel 2, an inner cylinder 4 fitted with the inner surface of the rear end portion of the rear barrel 3 and having a clip, and a tip member 6 threadedly engaged with the inner surface of the front end portion of the front barrel 2. The front barrel 2, the rear barrel 3, and the tip member 6 constitute the barrel 5. The inner cylinder 4 may also be included, referred to internally as the barrel 5. The tip member 6 may also be integrally formed with the front barrel 2. In the case where the tip member 6 is integrally formed, the front barrel 2 constitutes the tip. In this case, the tip can be attached and detached relative to the barrel 5. The mechanical pencil 1 is configured such that the lead (not shown) protrudes from the top of the barrel 5. In this specification, in the axial direction of the mechanical pencil 1, the lead side is defined as the "front" side, and the side opposite to the lead side is defined as the "rear" side.

[0034] The front barrel 2, rear barrel 3, and inner cylinder 4 are cylindrical components formed with approximately the same outer diameter. The nib component 6 is a cylindrical component formed into a generally conical shape that tapers towards the front. Inside the front end of the barrel 5, specifically inside the front end of the nib component 6, a slider 7 having a tip tube 15 for guiding the pen refill is configured to slide along the axial direction and rotate about the axial direction. A sleeve 50 is loosely fitted onto the outer surface of the slider 7. A retaining ring 60 is fitted onto the inner surface of the nib component 6, behind the sleeve 50, in a manner that surrounds the slider 7.

[0035] The front pen barrel 2 and the rear pen barrel 3 are connected by a cylindrical support member 32. Specifically, an external thread is formed on the outer surface of the support member 32, and internal threads are formed on the inner surface of the rear end portion of the front pen barrel 2 and the inner surface of the front end portion of the rear pen barrel 3. The internal thread at the rear end portion of the front pen barrel 2 engages with the external thread at the front end portion of the support member 32, and the internal thread at the front end portion of the rear pen barrel 3 engages with the external thread at the rear end portion of the support member 32. As a result, the front pen barrel 2 and the rear pen barrel 3 are connected. An annular support protrusion 32a, protruding radially inward, is formed on the inner surface of the rear of the support member 32.

[0036] The slider 7 is formed as a cylindrical shape that tapers in a stepped manner towards the front. The front end of the slider 7 protrudes from the front end of the pen barrel 5, i.e., the pen tip member 6, together with the tip tube 15. Alternatively, only the tip tube 15 may protrude from the front end of the pen barrel 5. A retaining clip 8 with a central through hole is disposed in the slider 7, located behind the tip tube 15. The through hole of the retaining clip 8 slides in contact with the outer surface of the pen refill, thereby temporarily holding the pen refill.

[0037] A cylindrical relay member 9 is threaded onto the rear end of the slider 7. An annular engaging protrusion 9a is provided on the outer surface of the rear portion of the relay member 9. A chuck unit 10 for holding the pen refill and a pen refill shell 13 are disposed inside the slider 7 and the relay member 9. The chuck unit 10 has a chuck body 11 and a cylindrical fastener 12 that surrounds the front end of the chuck body 11. At least the front half of the chuck body 11 is divided into three chuck pieces 11a along the axial direction, and a through hole for the pen refill is formed along the central axis. Each chuck piece 11a is formed with its front end separated from each other. The pen refill shell 13 is cylindrical and houses the pen refill inside. The rear end of the chuck body 11 is inserted into and fitted into the interior of the front end of the pen refill shell 13.

[0038] A coil spring 14 is arranged to surround the clip body 11. The front end of the coil spring 14 is supported by a stepped portion formed on the inner circumferential surface of the relay member 9, and the rear end of the coil spring 14 abuts against the front end face of the pen refill shell 13. Therefore, the coil spring 14 applies a rearward force to the clip body 11 and the pen refill shell 13. The clip body 11, which is subjected to a rearward force, can maintain a holding state of the pen refill by having its front ends approach each other when it is housed in the fastener 12. In addition, when writing pressure is applied to the pen refill, the clip body 11 retracts further and is housed in the fastener 12, and the pen refill is held by the clip body 11. Thus, the refill's retraction is prevented.

[0039] The outer surface of the fastener 12 engages with the inner surface of the front end of the relay member 9. Therefore, the slider 7, the relay member 9, and the clamp unit 10 can move along the axial direction within the pen barrel 5. The rear end of the relay member 9 is connected to the rotary drive mechanism 30, which will be described later.

[0040] At the rear end of the pen barrel 5, specifically at the rear end of the inner cylinder 4, a cylindrical press member 20 is provided as a press member, capable of moving back and forth relative to the pen barrel 5. The press member 20 is pushed rearward by a coil spring 21. A pen refill shell 13 is inserted into the interior of the front end of the press member 20. An eraser 22 is detachably mounted inside the rear end of the press member 20. A press cover 23 is detachably mounted on the outer surface of the rear end of the press member 20, which protects the eraser 22 from contamination, etc.

[0041] By performing a pressing operation that pushes the pressing member 20 or the pressing cover 23 forward, the pen refill shell 13 moves forward. As a result, the chuck body 11 is pushed forward and disengaged from the fastener 12. Subsequently, the pen refill held by the chuck body 11 also moves forward, and the chuck body 11 releases its grip on the pen refill. In short, the chuck unit 10 can perform pen refill gripping and releasing, thereby functioning to deliver the pen refill from the tip tube 15. When the pressing operation is released, the pressing member 20 retracts and returns to its original position using the force of the coil spring 21. At this time, the chuck body 11 retracts using the force of the coil spring 14. On the other hand, the pen refill is held by the retaining chuck 8 disposed within the slider 7. As a result, the pen refill is delivered from the tip tube 15, thus allowing the pen refill to be delivered in a predetermined amount each time the pressing operation is repeated. The chuck unit 10 can also be other chuck units, such as a ball chuck.

[0042] Figure 3 yes Figure 1 An enlarged cross-sectional view of the central portion of the mechanical pencil 1. A rotary drive mechanism 30 is disposed within the internal space of the rear barrel 3. The rotary drive mechanism 30 is connected to the rear end of the relay member 9. The lead shell 13 passes through the interior of the relay member 9 and the rotary drive mechanism 30, and is separate from the rotary drive mechanism 30. The rotary drive mechanism 30 is subjected to a rearward force by a shaft spring 31. That is, the front end of the shaft spring 31 is supported by the support protrusion 32a of the support member 32, and the rear end of the shaft spring 31 is supported by the front end face of the rotary drive mechanism 30, thereby applying a rearward force to the rotary drive mechanism 30.

[0043] The rotary drive mechanism 30 includes a cylindrical rotating body 40, a cylindrical upper cam forming member 41 serving as a first cam forming member, a cylindrical lower cam forming member 42 serving as a second cam forming member, a cylindrical cylinder member 43, a cylindrical torque eliminator 44, and a helical buffer spring 45. These components of the rotary drive mechanism 30 are integrated and modularized.

[0044] The outer surface of the rear end of the relay member 9 fits into the inner surface of the front end of the rotating body 40. Near the front end of the rotating body 40, there is a flange-shaped portion with a slightly larger diameter. A first cam surface 40a is formed on the rear end face of this portion, and a second cam surface 40b is formed on the front end face of this portion.

[0045] The upper cam forming member 41 surrounds the rotating body 40 behind the first cam surface 40a in a manner that allows the rotating body 40 to rotatably. The lower cam forming member 42 is fitted into the outer surface of the front end of the upper cam forming member 41. A first fixed cam surface 41a is formed on the front end face of the upper cam forming member 41 opposite to the first cam surface 40a of the rotating body 40. A second fixed cam surface 42a is formed on the inner surface of the front end of the lower cam forming member 42 opposite to the second cam surface 40b of the rotating body 40.

[0046] A cylindrical cylinder member 43 is fitted onto the outer surface of the rear end of the upper cam forming member 41. A through hole 43a is formed at the rear end of the cylinder member 43, through which the pen refill shell 13 can pass. A cylindrical torque eliminator 44, movable along the axial direction, is disposed inside the cylinder member 43. A buffer spring 45 is disposed between the inner surface of the front end of the torque eliminator 44 and the inner surface of the rear end of the cylinder member 43. The buffer spring 45 applies a force to the rotating body 40 forward by means of the torque eliminator 44.

[0047] Here, the relay member 9 transmits the backward and forward movements (buffering movements) of the pen refill based on the writing action to the rotary drive mechanism 30, i.e., the rotating body 40, and transmits the rotational motion of the rotating body 40 of the rotary drive mechanism 30 generated by the buffering movement to the chuck unit 10 in the state of holding the pen refill. Therefore, by means of the rotation of the relay member 9, the pen refill held by the chuck unit 10 also rotates.

[0048] When writing with the mechanical pencil 1, i.e., when no writing pressure is applied to the lead, the rotating body 40 is positioned forward by the force of the buffer spring 45 via the torque canceller 44. Therefore, the second cam surface 40b of the rotating body 40 abuts against the second fixed cam surface 42a, forming an engaged state. When writing with the mechanical pencil 1, i.e., when writing pressure is applied to the lead, the chuck unit 10 retracts against the force of the buffer spring 45, and the rotating body 40 also retracts. Therefore, the first cam surface 40a of the rotating body 40 abuts against the first fixed cam surface 41a, forming an engaged state. The lead and the rotating body 40 move forward, backward, or rotate as a unit.

[0049] Figure 4 This is a schematic diagram illustrating the rotation drive of the rotating body 40 of the rotation drive mechanism 30. Figure 5 It continues Figure 4 A schematic diagram illustrating the rotation drive of the rotating body 40. Figure 4 and Figure 5In the rotating body 40, a first cam surface 40a is formed in a circular shape on the upper side surface, i.e. the rear end surface, and a second cam surface 40b is formed in a circular shape on the lower side surface, i.e. the front end surface, and a second cam surface 40b is formed in a circular shape ...

[0050] A first fixed cam surface 41a, which is serrated along the circumferential direction, is also formed on the annular end face of the upper cam forming member 41 opposite to the first cam surface 40a of the rotating body 40. A second fixed cam surface 42a, which is serrated along the circumferential direction, is also formed on the annular end face of the lower cam forming member 42 opposite to the second cam surface 40b of the rotating body 40. The cam surfaces formed on the first cam surface 40a and the second cam surface 40b of the rotating body 40, and the cam surfaces formed on the first fixed cam surface 41a of the upper cam forming member 41 and the second fixed cam surface 42a of the lower cam forming member 42, are formed with approximately the same spacing between them.

[0051] Figure 4 (A) shows the relationship between the advanced rotating body 40, the upper cam forming member 41, and the lower cam forming member 42 in a state where no writing pressure is applied to the pen refill. In this state, the second cam surface 40b formed on the rotating body 40 abuts against the second fixed cam surface 42a of the lower cam forming member 42 under the force of the buffer spring 45. At this time, the first cam surface 40a of the rotating body 40 and the first fixed cam surface 41a of the upper cam forming member 41 are set to be offset in the axial direction by half a phase (half a pitch) relative to one tooth of the cam.

[0052] Figure 4 (B) shows the initial state in which writing pressure is applied to the lead due to writing with the mechanical pencil 1. In this state, the rotating body 40 retracts along with the retraction of the chuck unit 10, causing the buffer spring 45 to contract and retract. As a result, the rotating body 40 moves towards the upward cam forming member 41 and abuts against the first fixed cam surface 41a.

[0053] then, Figure 4 (C) shows a state in which the rotating body 40 is retracted while sliding against the first fixed cam surface 41a of the upper cam forming member 41 due to further writing pressure applied to the pen refill. That is, the rotating body 40 receives a rotational drive corresponding to half a phase (half a pitch) of one tooth of the first cam surface 40a. In this state, the first cam surface 40a of the rotating body 40 engages with the first fixed cam surface 41a of the upper cam forming member 41.

[0054] In addition, Figure 4 and Figure 5The ○ mark depicted at the center of the rotating body 40 indicates the amount of rotational movement of the rotating body 40. Therefore, in Figure 4 In the state shown in (C), the second cam surface 40b of the rotating body 40 and the second fixed cam surface 42a of the lower cam forming member 42 are set to be offset in the axial direction by half a phase (half a pitch) relative to one tooth of the cam.

[0055] then, Figure 5 (D) shows the initial state after writing with the mechanical pencil 1 has ended and the writing pressure on the lead has been released. In this state, the rotating body 40 moves forward under the force of the buffer spring 45. As a result, the rotating body 40 moves towards the downward cam forming member 42 and abuts against the second fixed cam surface 42a.

[0056] then, Figure 5 (E) shows the state in which the rotating body 40 advances while sliding against the second fixed cam surface 42a of the lower cam forming member 42 under the force of the buffer spring 45. That is, the rotating body 40 again receives a rotational drive corresponding to half a phase (half a pitch) of one tooth of the second cam surface 40b. In this state, the second cam surface 40b of the rotating body 40 engages with the second fixed cam surface 42a of the lower cam forming member 42.

[0057] Therefore, such as Figure 4 and Figure 5 As indicated by the circle mark at the center of the rotating body 40, the rotating body 40, under writing pressure, reciprocates along its axial direction (i.e., moves back and forth). It receives a rotational drive corresponding to one tooth (one pitch) of the first cam surface 40a and the second cam surface 40b. The pen refill, held by the chuck unit 10, is similarly driven to rotate. Therefore, by utilizing each back-and-forth movement of the rotating body 40 in the axial direction caused by writing, the rotating body 40 receives a rotational motion corresponding to one tooth of the cam. By repeating this action, the pen refill is sequentially driven to rotate. This prevents uneven wear of the pen refill during writing and prevents significant variations in line thickness and depth.

[0058] The torque eliminator 44, which receives the force of the buffer spring 45 and pushes the rotating body 40 forward, slides between its front end face and the rear end face of the rotating body 40, thereby preventing the rotational motion of the rotating body 40 from being transmitted to the buffer spring 45. That is, by using the torque eliminator 44, the rotational motion of the rotating body 40 is prevented from being transmitted to the buffer spring 45, thereby preventing the buffer spring 45 from generating a counter-torque that would hinder the rotational motion of the rotating body 40.

[0059] As described above, the mechanical pencil 1 includes: a rotating member having a clamping unit 10 capable of holding and releasing the lead, a relay member 9 surrounding the clamping unit 10, a slider 7, and a tip tube 15; and a rotation drive mechanism 30 having a rotating body 40 that receives a backward movement in the axial direction caused by writing pressure on the lead held by the clamping unit 10 and a forward movement in the axial direction caused by the release of writing pressure, thereby driving the rotating body 40 to rotate in one direction. Furthermore, the rotating body 40 is configured to be connected to the rear end of the relay member 9, and the slider 7 is detachably connected to the front end of the relay member 9. The rotating member rotates under the rotational driving force of the rotating body 40, thereby rotating the lead held by the clamping unit 10.

[0060] Figure 6 yes Figure 1 A three-dimensional diagram of the sleeve 50 of a mechanical pencil 1. Figure 7 yes Figure 6 The front view of sleeve 50. Figure 8 yes Figure 6 Longitudinal sectional view of sleeve 50.

[0061] The sleeve 50 is a cylindrical component. The inner surface of the sleeve 50 is formed into a cylindrical shape with approximately the same inner diameter in the axial direction. The sleeve 50 includes: a sleeve body 51, which is formed into a cylindrical shape with approximately the same outer diameter; a flange 52 formed on the outer surface of the rear end of the sleeve body 51; a first tapered portion 53 located at the front of the sleeve body 51; a second tapered portion 54 located at the front of the first tapered portion 53; and three protrusions 55 located on the inner surface of the front end of the sleeve 50. The three protrusions 55 are convex curved protrusions. The three protrusions 55 are arranged at equal intervals along the circumferential direction.

[0062] The first tapered portion 53 and the second tapered portion 54 are formed to taper towards the front. The outer diameter of the rear end of the first tapered portion 53 is slightly smaller than the outer diameter of the sleeve body 51. Therefore, the first tapered portion 53 is connected to the sleeve body 51 by means of a forward-facing annular step 51a. The rear end of the second tapered portion 54 is connected to the front end of the first tapered portion 53. The taper of the second tapered portion 54 is greater than the taper of the first tapered portion 53. A third tapered portion 52a that tapers towards the front is formed on the outer surface of the flange portion 52. Alternatively, the sleeve 50 may not have the first tapered portion 53 and the second tapered portion 54, and the sleeve body 51 may be extended. Furthermore, the sleeve 50 may not have the third tapered portion 52a.

[0063] Four recesses 56 are provided at equal intervals along the circumference of the flange portion 52. Each recess 56 has a bottom surface 56a orthogonal to the central axis and a curved side surface 56b orthogonal to the bottom surface 56a by cutting off the periphery of the front side of the flange portion 52. A flat portion 57 is provided in a part of the flange portion 52 by cutting away along a plane parallel to the axial direction. The sleeve 50 may have at least one recess 56 or may not have a recess 56.

[0064] like Figure 2 As shown, the sleeve 50 engages with the outer surface near the front end of the slider 7. Specifically, a slider body 7a with approximately the same outer diameter is formed near the front end of the slider 7. The inner diameter of the sleeve 50 is formed to be the same as or slightly larger than the outer diameter of the slider body 7a. On the other hand, the diameter of the inscribed circle of the three protrusions 55 of the sleeve 50 is formed to be slightly smaller than the outer diameter of the slider body 7a. Therefore, the sleeve 50 is engaged with the slider body 7a of the slider 7 by elastic deformation of the three protrusions 55, thereby loosely engaging with the slider 7. Thus, the sleeve 50 can move forward, backward, or rotate integrally with the slider 7. Therefore, it can also be called a rotating member, including the sleeve 50. The sleeve 50 can be arbitrarily configured as long as it can loosely engage with the slider 7.

[0065] For example, as a sleeve, it can also be like Figure 9 It is constructed as shown in the sleeve 150. Figure 9 This is a perspective view of another sleeve 150. The basic shape of sleeve 150 is the same as that of sleeve 50 described above, except that the shape of its inner surface differs from that of sleeve 50. On the inner surface of sleeve 150, three flat locking surfaces 158 are provided along the axial direction, thickening the cylindrical inner surface. The three locking surfaces 158 are arranged at equal intervals along the circumference. On the inner surface of the front end of sleeve 150, between adjacent locking surfaces 158, three protrusions 155 are provided. The three protrusions 155 are convex curved protrusions. The three protrusions 155 are arranged at equal intervals along the circumference.

[0066] The sleeve 150, like the sleeve 50 described above, is fitted onto the outer surface near the front end of the slider 7. The diameter of the inscribed circle of the three locking surfaces 158 of the sleeve 150 is formed to be the same as or slightly smaller than the outer diameter of the slider body 7a of the slider 7. On the other hand, the diameter of the inscribed circle of the three protrusions 155 of the sleeve 150 is formed to be slightly smaller than the outer diameter of the slider body 7a of the slider 7. Therefore, the sleeve 150 is elastically deformed by the three protrusions 155 or the three locking surfaces 158 while being engaged with the slider body 7a of the slider 7, thus loosely fitting into the slider 7. As a result, the sleeve 150 can move forward, backward, or rotate integrally with the slider 7. Therefore, the sleeve 150 may also be referred to internally as a rotating member.

[0067] Refer again Figure 2 The locking ring 60 is a continuous annular component. The cross-section of the locking ring 60 is approximately square. The outer diameter of the locking ring 60 is slightly larger than the corresponding inner diameter of the pen tip component 6. Therefore, the locking ring 60 fits into the portion of the inner surface of the pen tip component 6 located behind the sleeve 50. The inner diameter of the locking ring 60 is larger than the corresponding outer diameter of the slider 7, and the locking ring 60 surrounds the slider 7.

[0068] The inner surface of the tip member 6 at its front end is provided with a support surface 6a, which is cylindrical with approximately the same inner diameter, throughout the axial direction. The rotational member driven by the rotational drive mechanism 30, specifically the slider 7 of the relay member 9 connected to the rotating body 40 of the rotational drive mechanism 30, and the sleeve 50 fitted with the slider 7, are directly or indirectly supported by the support surface 6a of the tip member 6. In detail, the support surface 6a of the tip member 6 not only directly supports the sleeve 50 by contact with it, but also indirectly supports the sleeve 50 by means of the viscous fluid 70 described later.

[0069] A viscous fluid 70 is applied between the support surface 6a of the pen tip member 6 and the outer surface of the sleeve 50, specifically the outer surface of the sleeve body 51. That is, the viscous fluid 70 is applied at least throughout the contact surface between the support surface 6a and the outer surface of the sleeve 50. At least a portion of the outer surface of the sleeve body 51 of the sleeve 50 forms a retaining portion in order to retain the viscous fluid 70. Furthermore, since the sleeve 50 is fitted into the slider 7, the slider 7 can also be said to have a retaining portion. The viscous fluid 70 is silicone oil, silicone grease, etc., for example, silicone grease G501 manufactured by Shin-Etsu Chemical Industry Co., Ltd. is used.

[0070] Figure 10 It is used to explain in stages. Figure 1 An enlarged cross-sectional view of the front end of the mechanical pencil 1's click mechanism. Figure 10 The pen refill was omitted. Figure 10 (A) represents the state before the click operation. From Figure 10 Starting from the state shown in (A), press the push member 20 or the push cover 23 forward to begin the push operation. During the push operation, the relay member 9 moves forward together with the lead housing 13. The forward movement of the relay member 9 is limited by the engagement of the engagement protrusion 9a of the relay member 9, located in the central part of the mechanical pencil 1, with the support protrusion 32a of the support member 32. At this time, the sleeve 50, which moves forward together with the relay member 9, is limited by the engagement of the flange 52 inside the tip member 6 with the rearward-facing engagement surface 6b. Figure 10 (B)

[0071] When the clicker 20 or clicker cap 23 is pressed further forward using the clicker operation, as described above, the chuck body 11 holds the pen refill (not shown) while pushing it forward. Figure 10 (C)). When the press of the button is released, the main body 11 of the chuck retracts under the force of the coil spring 14, thus dispensing the pen refill. Additionally, the relay component 9, the slider 7, and the sleeve 50 also retract and return to their original positions. Figure 10 (A)). Furthermore, through from Figure 10 The state shown in (A) applies a writing load to the pen tip during the writing action. In short, as part of the buffering action, the relay member 9, the slider 7, and the sleeve 50 move back slightly as a whole. Figure 10 (D)). By retracting the relay member 9, as described above, the rotating body 40 receives a rotational drive corresponding to half a phase (half a pitch) of one tooth of the first cam surface 40a, and thus the slider 7 and the sleeve 50 also rotate integrally about the central axis. Furthermore, the engaging force between the slider 7 and the sleeve 50, in other words, the force required to remove the sleeve 50 from the slider 7, is preferably less than the spring load of the helical spring 14 that applies a rearward force to the clip body 11 and the pen refill shell 13.

[0072] As mentioned above, typically in a mechanical pencil configured to rotate the lead, a gap exists between the inner surface of the front end of the pencil barrel and the outer surface of the slider, based on manufacturing tolerances, in order to allow the slider to rotate and move in the axial direction.

[0073] In the mechanical pencil 1, the gaps are filled with a viscous fluid 70. Therefore, even if the tip of the lead and the sleeve 50 wobble radially, the wobble is mitigated by the viscosity of the viscous fluid 70. Furthermore, even if the sleeve 50 collides with the inner surface of the pencil barrel 5 due to radial wobble, the collision is mitigated by the viscosity of the viscous fluid 70, and the collision noise is minimized.

[0074] Furthermore, according to the viscous fluid 70, it not only mitigates radial wobble but also cushions the rotation drive mechanism 30. That is, in conventional rotation drive mechanisms required to rotate the lead, the slight backward and forward movements (cushioning) of the lead based on writing motion, as described above, are sometimes noticeable to the user as axial wobble. According to the mechanical pencil 1, the viscous fluid 70 effectively mitigates both axial and radial wobble.

[0075] In summary, by distributing a viscous fluid 70 between the inner surface of the front end of the pencil barrel 5 and the sleeve body 51 of the sleeve 50, which is a retaining part included as a rotating member, the radial and axial wobbling of the lead, the slider 7, and the sleeve 50 can be mitigated. As a result, the user can experience a good writing feel, a substantial feel, or a premium feel when writing with the mechanical pencil 1.

[0076] The viscous fluid 70 is selected in a way that balances a high viscosity that prevents it from dripping even due to changes in posture during writing or handling, and a low viscosity that does not impede the rotation and axial movement of the rotating component. In short, the low viscosity that does not impede the rotation and axial movement of the rotating component means that if the viscosity is too high, the axial movement of the rotating component cannot be properly achieved. As a result, the cams of the rotating body 40, the upper cam forming member 41, and the lower cam forming member 42 cannot cooperate properly, and the rotating component cannot rotate properly. Therefore, the viscous fluid 70 has a low viscosity that does not impede the rotation and axial movement of the rotating component.

[0077] However, often, when the lead breaks inside the mechanical pencil, specifically between the clip and the clip unit, due to factors such as the pencil falling, the broken lead can block the clip and prevent the lead from being ejected. In this case, the mechanical pencil needs to be disassembled to remove the lead between the clip and the clip unit.

[0078] Figure 11 yes Figure 1 A partially enlarged cross-sectional view of the mechanical pencil 1 after the front barrel 2 has been removed. For example, in order to access the space between the retaining clip 8 and the clip unit 10 to remove a broken lead, firstly, the front barrel 2 or the tip member 6 needs to be removed from the mechanical pencil 1, and then the slider 7, which is threaded into the relay member 9, needs to be removed. Figure 11 As shown, if the front pen barrel 2 is removed, the sleeve 50 disposed inside the pen tip component 6 is also removed as a whole along with the pen tip component 6 which is threaded to the front end of the front pen barrel 2.

[0079] That is, when the front pen barrel 2 is removed, the sleeve 50, loosely fitted into the slider 7, is removed from the slider 7 by abutting against the locking ring 60, remaining inside the pen tip member 6. Similarly, when the pen tip member 6 is removed from the front pen barrel 2 while the front pen barrel 2 is still connected to the rear pen barrel 3, the sleeve 50 abuts against the locking ring 60, remaining inside the pen tip member 6. More specifically, when removing the front pen barrel 2 or the pen tip member 6, the sleeve 50 and the slider 7 retract together relative to the pen tip member 6, but the rear end face of the sleeve 50 abuts against the front end face of the locking ring 60, and the sleeve 50 is pulled out of the slider 7. Therefore, the engagement force of the sleeve 50 relative to the slider 7 is smaller than the engagement force of the locking ring 60 relative to the pen tip member 6.

[0080] The locking ring 60 constitutes a locking portion that locks the retracted sleeve 50, which includes the retaining portion. The locking ring 60 is a continuous annular member, but it can also be a partially separated letter-C shaped annular member, or it can have a circular or rectangular cross-sectional shape. Besides the separate locking ring 60, the locking portion can also be a locking protrusion integrally provided on the inner surface of the pen tip member 6. In this case, the locking protrusion can be annularly provided on the inner surface of the pen tip member 6, or it can be a single protrusion or multiple protrusions arranged circumferentially.

[0081] With the rear end face of the sleeve 50 abutting against the front end face of the locking ring 60, the front end face of the sleeve 50 is positioned in the axial direction at the same position as or slightly behind the front end face of the pen tip member 6. In short, the sleeve 50 does not protrude from the pen tip member 6 in this state. Therefore, even if the pen barrel 2 or pen tip member 6 with the sleeve 50 remaining falls from the front end onto a floor or other surface, the sleeve 50 will not collide with the ground. Therefore, the force that would cause the sleeve 50, and consequently the locking ring 60, to fall backward will not act on the sleeve 50. In other words, the length of the sleeve 50 in the axial direction and the engagement position of the locking ring 60 in the axial direction of the pen tip member 6 are determined such that the sleeve 50 does not protrude from the front end of the pen barrel 5 at its rearward limit.

[0082] As described above, a viscous fluid 70 is applied between the support surface 6a of the tip member 6 and the outer surface of the sleeve 50. Since the sleeve 50 remains inside the tip member 6, the viscous fluid 70 is retained within the tip member 6 and will not be applied to the outer surface of the slider 7 or flow out to the outside. Therefore, even when disassembling the mechanical pencil 1 after removing broken leads, the viscous fluid 70 will not soil hands or clothes. Furthermore, when assembling the mechanical pencil 1, it can be easily reassembled by inserting the slider 7, which is mounted on the relay member 9, into the sleeve 50.

[0083] As described above, a first tapered portion 53 with a smaller diameter is provided in front of the sleeve body 51 of the sleeve 50 via a step 51a, and a second tapered portion 54 is provided further forward. By providing the step 51a and the first tapered portion 53, and utilizing the surface tension of the viscous fluid 70, the viscous fluid 70 applied to the outer surface of the sleeve body 51 is prevented from diffusing across the step 51a to the first tapered portion 53 and then to the second tapered portion 54. Furthermore, by providing the step 51a, the first tapered portion 53, and the second tapered portion 54, the viscous fluid 70 can be prevented from being applied to unwanted parts of the sleeve 50 when assembling the mechanical pencil 1 after removing broken leads. Four recesses 56 are provided on the flange portion 52 of the sleeve 50. By having recesses 56 in the sleeve 50, the viscous fluid 70 flowing with the relative movement of the sleeve 50 relative to the tip member 6 is temporarily stored, preventing the viscous fluid 70 from diffusing to the outside. The shape of the recess 56 can be arbitrarily formed as long as it can temporarily store the viscous fluid 70.

[0084] According to the mechanical pencil 1, since the amount of viscous fluid 70 can be adjusted according to the gap, the dimensional tolerance between parts is high. Furthermore, even if a gap deviation occurs, the fluidity of the viscous fluid 70 can be used to fill the gap corresponding to the deviation. During the rotation of the slider 7 and the sleeve 50 relative to the pencil barrel 5, i.e., the tip member 6, and their movement in the radial and axial directions, the presence of the viscous fluid 70 prevents wear caused by friction between parts, allowing the mechanical pencil 1 to be used for a long time. Since the user does not come into contact with the viscous fluid 70, deterioration of the viscous fluid 70 is less likely during long-term use, maintaining the same performance and effect over a long period.

[0085] Figure 12 This is a partial exploded perspective view of the mechanical pencil 100 according to the second embodiment of the present invention. Figure 13 yes Figure 11 An enlarged cross-sectional view of the front end of the mechanical pencil 100. Figure 14 yes Figure 11 A partially enlarged cross-sectional view of the mechanical pencil 100 after the tip member 106 has been removed. The mechanical pencil 100 differs from the mechanical pencil 1 of the first embodiment in that it lacks a sleeve and in the shapes of the tip member, slider, and relay member. The mechanical pencil 100 includes a tip member 106, a slider 180, and a relay member 190.

[0086] On the inner surface of the pen tip member 106, a locking portion 106c, which is a ring-shaped protrusion, is provided instead of the locking ring 60 of the mechanical pencil 1 of the first embodiment. On the inner surface of the front end of the pen tip member 6, a support surface 106a, which is formed into a cylindrical surface with approximately the same inner diameter, is provided throughout the axial direction.

[0087] The slider 180 of the mechanical pencil 100 is formed as a cylindrical shape that tapers in a stepped manner towards the front. The slider 180 includes: a slider body 181, which is cylindrical with approximately the same outer diameter near its front end; a flange 182 formed on the outer surface of the rear end of the slider body 181; and a larger diameter rear slider portion 183 located behind the flange 182. Two rectangular notches 184 are provided at the rear end of the slider 180, i.e., the rear end of the rear slider portion 183. The two notches 184 are located on opposite sides of the central axis of the slider 180. The front end of the slider 180 protrudes from the front end of the barrel 5, i.e., the tip member 106, together with the tip tube 15. Alternatively, only the tip tube 15 may protrude from the front end of the barrel 5.

[0088] The relay member 190 has: two limiting protrusions 191 located on the side near the front end; two claw portions 192 extending forward over the chuck unit 10; and claw protrusions 193 located on the inner surface of the front end of each claw portion 192. The two limiting protrusions 191 are located on opposite sides of each other with respect to the central axis of the relay member 190. Similarly, the two claw portions 192 are located on opposite sides of each other with respect to the central axis of the relay member 190. The limiting protrusions 191 and claw portions 192 are aligned in the axial direction, but may not be aligned.

[0089] In the assembled state of the mechanical pencil 100, the limiting protrusion 191 of the relay member 190 is disposed within the corresponding notch 184 of the slider 180. Thus, the slider 180 is locked to the relay member 190 in the rotational direction, and the slider 180 can rotate integrally with the relay member 190. On the other hand, the axial movement of the limiting protrusion 191 of the relay member 190 and the corresponding notch 184 of the slider 180 is not locked. The inner surface of the slider rear portion 183 of the slider 180 loosely fits into the outer surface of the front end portion of the relay member 190. Therefore, the slider 180 can move forward or backward integrally with the relay member 190. Furthermore, the fastener 12, which advances along with the chuck body 11 through a click operation, is locked to the claw protrusion 193 of the claw portion 192. As a result, the chuck body 11 and the lead can be further advanced relative to the fastener 12, and the lead can be dispensed.

[0090] A viscous fluid 70 is applied between the support surface 106a of the pen tip member 106 and the outer surface of the slider 180, specifically the outer surface of the slider body 181. That is, the viscous fluid 70 is applied at least throughout the contact surface between the support surface 106a and the outer surface of the slider 180. At least a portion of the outer surface of the slider body 181 of the slider 180 forms a retaining portion in order to retain the viscous fluid 70.

[0091] By having a viscous fluid 70 in the mechanical pencil 100, the same effect as that of the mechanical pencil 1 in the first embodiment is achieved. That is, it is able to mitigate the radial and axial wobble caused by the gap between the inner surface of the tip member 106 and the outer surface of the slider 180.

[0092] In the mechanical pencil 100, in order to access the space between the clip 8 and the clip unit 10 to remove a broken lead, firstly, the front barrel 2 or the tip component 106 needs to be removed from the mechanical pencil 100, and then the slider 180, which is threadedly engaged with the relay component 109, needs to be removed. Figure 14 As shown, if the pen tip component 106 is removed, the slider 180 disposed inside the pen tip component 6 is also removed as a whole.

[0093] That is, when the pen barrel 2 or the pen tip component 106 is removed, the slider 180, which is loosely fitted into the relay component 190, is removed from the relay component 190 and remains inside the pen tip component 106. In detail, when the pen tip component 106 is removed, the slider 180 and the relay component 190 retract together relative to the pen tip component 106, but the flange portion 182 of the slider 180 abuts against the locking portion 106c of the pen tip component 106, and the slider 180 is pulled out from the relay component 190.

[0094] At this time, as described above, the movement of the limiting protrusion 191 of the relay member 190 and the corresponding notch 184 of the slider 180 in the axial direction is not locked, so it does not hinder the pull-out of the slider 180. The slider 180 and the relay member 190 can be arbitrarily configured as long as they are locked in the rotational direction but not locked in the axial direction. For example, only one limiting protrusion 191 and one notch 184 can be provided, or more than three can be provided. In addition, the slider may not be a notch that penetrates the wall thickness, but a groove that extends along the axial direction on the outer surface.

[0095] By retaining the slider 180 within the tip member 106, the viscous fluid 70 is kept within the tip member 106 and does not flow out. Therefore, even when disassembling the mechanical pencil 1 after removing broken leads, the viscous fluid 70 will not stain hands or clothes. Furthermore, when assembling the mechanical pencil 1, it can be easily reassembled by inserting the relay member 9 into the slider 180.

[0096] According to the mechanical pencil 100, since the amount of viscous fluid 70 can be adjusted according to the gap, the dimensional tolerance between parts is high. Furthermore, even if a gap deviation occurs, the fluidity of the viscous fluid 70 can be used to fill the gap corresponding to the deviation. During the rotation of the slider 180 relative to the barrel 5, i.e., the tip member 106, and its movement in the radial and axial directions, the presence of the viscous fluid 70 prevents wear caused by friction between parts, allowing the mechanical pencil 100 to be used for a long time. Since the user does not come into contact with the viscous fluid 70, deterioration of the viscous fluid 70 is less likely during long-term use, maintaining the same performance and effect over a long period.

[0097] In summary, according to the mechanical pencil 1 of the first embodiment and the mechanical pencil 100 of the second embodiment, the pencil barrel has a tip, i.e., a front pencil barrel or tip member, which can be attached and detached relative to the pencil barrel, and is configured such that when the tip is removed from the pencil barrel, the retaining part, i.e., the sleeve 50 or the sliding member 180, which holds the viscous fluid 70, disengages from the rotating member together with the tip.

[0098] Figure 15 This is an enlarged cross-sectional view of the front end of the mechanical pencil 200 according to the third embodiment of the present invention. The mechanical pencil 200 is the same as a conventional mechanical pencil with a rotating lead, except that it has the viscous fluid 70. Furthermore, the slider 7, the relay member 9, and the clip unit 10 are substantially the same as those of the mechanical pencil 1 of the first embodiment. The mechanical pencil 200 does not have a tip member, and the front end of the slider 7 protrudes from the front end of the front barrel 202, which has the grip portion 202a.

[0099] As described above, the slider 7 is formed as a cylinder with a stepped outer diameter that tapers towards the front. The slider 7 has a slider body 7a that is formed as a cylinder with approximately the same outer diameter near the front end. A support surface 202b with approximately the same inner diameter is provided throughout the axial direction on the inner surface of the front end of the pen barrel 202.

[0100] A viscous fluid 70 is applied between the support surface 202b of the front pen barrel 202 and the outer surface of the slider 7, specifically the outer surface of the slider body 7a. That is, the viscous fluid 70 is applied at least throughout the contact surface between the support surface 106a and the outer surface of the slider 7. At least a portion of the outer surface of the slider body 7a of the slider 7 forms a retaining portion in order to retain the viscous fluid 70.

[0101] By incorporating a viscous fluid 70 into the mechanical pencil 200, the same effect as that of the mechanical pencil 1 in the first embodiment is achieved. That is, it can mitigate the radial and axial wobble caused by the gap between the inner surface of the front barrel 202 and the outer surface of the slider 7.

[0102] According to the mechanical pencil 200, since the amount of viscous fluid 70 can be adjusted according to the gap, the dimensional tolerance between parts is high. Furthermore, even if a gap deviation occurs, the fluidity of the viscous fluid 70 can be used to fill the gap corresponding to the deviation. During the rotation of the slider 7 relative to the pencil barrel 5, i.e., the front pencil barrel 202, and its movement in the radial and axial directions, the presence of the viscous fluid 70 prevents wear caused by friction between parts, allowing the mechanical pencil 200 to be used for a long time. Since the user does not come into contact with the viscous fluid 70, deterioration of the viscous fluid 70 is less likely during long-term use, maintaining the same performance and effect over a long period.

[0103] As described above, the mechanical pencil of the above embodiment includes: a pencil barrel; a rotating member having a clamping unit capable of holding and releasing the lead and a sliding member having a holding portion, the rotating member partially protruding from the front end of the pencil barrel; and a rotation drive mechanism having a rotating body connected to the rotating member, receiving a backward movement in the axial direction caused by writing pressure borne by the lead held by the clamping unit and a forward movement in the axial direction caused by the release of writing pressure, and driving the rotating body to rotate in one direction, configured such that the rotating member rotates by receiving the rotational driving force of the rotating body, thereby rotating the lead held by the clamping unit, and a viscous fluid is applied between the inner surface of the front end of the pencil barrel and the outer surface of the holding portion.

[0104] Explanation of reference numerals in the attached figures

[0105] 1. Mechanical pencil; 2. Front barrel; 3. Rear barrel; 4. Inner cylinder; 5. Barrel; 6. Tip component; 6a. Support surface; 6b. Engaging surface; 7. Slider; 7a. Slider body; 8. Holding chuck; 9. Relay component; 10. Chuck unit; 13. Lead shell; 14. Coil spring; 15. Top tube; 50. Sleeve; 51. Sleeve body; 51a. Step; 52. Flange; 60. Locking ring; 70. Viscous fluid.

Claims

1. A mechanical pencil, wherein, This mechanical pencil has the following features: pen; A rotating member having a clamping unit capable of holding and releasing the pen refill and a sliding member having a holding portion, the rotating member being configured to partially protrude from the front end of the pen barrel; as well as A rotary drive mechanism has a rotating body connected to the rotating member, which receives a backward movement in the axial direction caused by the writing pressure exerted on the pen refill held by the chuck unit and a forward movement in the axial direction caused by the release of the writing pressure, thereby driving the rotating body to rotate in one direction. The pen refill held by the chuck unit rotates by receiving the rotational driving force of the rotating body through the rotating member. A viscous fluid is applied between the inner surface of the front end portion of the pen barrel and the outer surface of the retaining portion.

2. The mechanical pencil according to claim 1, wherein, The pen barrel has a tip that includes the front end and is detachable relative to the pen barrel, and is configured such that when the tip is removed from the pen barrel, the retaining portion disengages from the rotating member together with the tip.

3. The mechanical pencil according to claim 2, wherein, The rotating component also has a cylindrical sleeve that has the retaining portion and is detachable relative to the sliding component.

4. The mechanical pencil according to claim 3, wherein, The front end of the sleeve is formed into a cone shape or has a smaller diameter compared to the rear end.

5. The mechanical pencil according to claim 3, wherein, The sleeve has an annular flange at its rear end.

6. The mechanical pencil according to claim 5, wherein, At least one recess is provided on the front end face of the flange portion.

7. The mechanical pencil according to any one of claims 2 to 6, wherein, The rod tip is provided with a locking part that locks the retraction of the retaining part.

8. The mechanical pencil according to claim 7, wherein, The locking part is a component that is separate from the rod tip.

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