Automatic Pencil

Abstract

The mechanical pencil (1) includes: a ball chuck (11); a rotary drive mechanism (30) having a rotor (40); a feed cam surface (54) having a step (55) in the axial direction; an input member that rotates by receiving the rotary drive force of the rotor; a contact member (65c) that abuts against the feed cam surface; and an output member having a slider (9) having a holding chuck (10) for holding the lead (7). The contact member moves along the feed cam surface according to the rotation of the output member. By the forward movement of the slider when the contact member falls into the step, the lead held by the holding chuck is pulled out by the ball chuck. It also has a clutch mechanism that transmits the rotational motion of the input member to the output member, such that when the input member rotates only by a first rotation angle, the output member rotates only by a second rotation angle less than the first rotation angle.

Description

Technical Field

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

[0002] In mechanical pencils, for example, a pressing operation is performed by pressing a pressing part located at the rear end of the cylinder, which then feeds a certain amount of lead from the tip component or slider mounted at the front end of the cylinder. Since the lead wears down with each writing action, a pressing operation must be performed for each certain amount of writing action.

[0003] Mechanical pencils that automatically feed the lead sequentially using writing pressure during writing are known (see Patent Document 1). The mechanical pencil described in Patent Document 1 includes: a ball bearing that holds the lead; a rotary drive mechanism that rotates a rotor in one direction due to a backward movement in the axial direction caused by the writing pressure received by the lead held by the ball bearing and a forward movement in the axial direction caused by the release of the writing pressure; and a lead feeding mechanism that includes a cam member that feeds the lead forward due to the rotational driving force of the rotor in the rotary drive mechanism and a retaining chuck. The ball bearing is configured to allow the lead to move forward and prevent it from moving backward.

[0004] The ball bearing chuck, as described below, comprises: a cylindrical clamp; a chuck body disposed within the clamp and holding the pen refill; and a plurality of balls. A widening conical surface is formed on the inner circumferential surface of the clamp, facing forward. When writing pressure is applied to the pen refill, the chuck body and the balls retract together, with the balls abutting against the conical surface within the cylindrical clamp. The further the balls retract, the closer they move along the conical surface to the center. Due to the balls moving towards the center, the chuck body also moves towards the center, resulting in the pen refill being clamped and held by the chuck body. This prevents the pen refill from retracting further. On the other hand, when a force is applied to pull the pen refill forward, the balls and the chuck body advance together. As a result, because the clamping force caused by the conical surface is released via the balls, that is, because the chuck body does not receive any force from the clamp, the pen refill can be pulled forward without resistance. In addition, the chuck body is pushed backward by a coil spring.

[0005] The core delivery mechanism includes: a cam member having a cam surface that gradually rises circumferentially and a step in the axial direction; and a slider with an abutment. The slider is pushed forward by a spring, thereby causing the abutment to abut against the cam surface. Furthermore, the slider is connected to a rotary drive mechanism and rotates under its rotational drive. During this rotation, the abutment moves in a manner that gradually rises along the cam surface of the cam member, and simultaneously, the slider slowly retracts in the axial direction.

[0006] Then, when the abutment of the slider reaches the step of the cam member, the abutment falls along the step by the action of the spring that pushes the slider. At this instant, the slider also receives a forward movement corresponding to the height difference of the step. At this time, since the retaining chuck arranged in the slider also moves forward in the same way, the pen refill is delivered by pulling out from the ball chuck and sliding into contact with and being held by the retaining chuck. That is, when the rotor rotates once, the abutment rotates once along the cam surface to deliver the pen refill. [Previous Technical Documents] [Patent Literature]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2016-153246 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] Ideally, the lead delivery mechanism should deliver a lead of the same length as the lead length reduced due to wear (wear amount). This allows the user to continue writing without pressing down. The lead delivery amount depends on the height of the step on the cam surface. However, in the construction of the ball bearing chuck, the lead's forward distance due to the step on the cam surface does not directly determine the lead delivery amount.

[0010] In other words, after the pen refill is pulled out of the ball bearing chuck by pressing or by the refill delivery mechanism, and before writing pressure is applied to the pen refill, there is still room for further retraction in the chuck body, the ball bearing, and even the pen refill (hereinafter referred to as "gap"). Specifically, the gap is about 0.2mm. For example, if the number of writing strokes (strokes) required for one revolution of the rotor is set to 40, the wear of the pen refill, although also depending on the amount of frictional resistance with the writing pressure and the writing surface, is approximately 0.05mm. Considering the gap, when the step height of the cam surface is set to 0.25mm, the wear caused by the writing action is the same as the delivery amount caused by the refill delivery mechanism, and the user can continue writing without pressing.

[0011] However, the gap typically has an error (tolerance) within a range of approximately ±0.1mm. Therefore, even if the step height of the cam surface of the refill delivery mechanism is set to 0.25mm, and the refill is delivered by 0.25mm, considering the gap error, there is a possibility that the refill may retract by more than 0.25mm. That is, the error in the refill delivery amount is 0.05mm ± 0.1mm, which may result in the refill not being delivered at all. On the other hand, considering the gap, the step height of the cam surface may be increased, for example, to 0.5mm, which would result in too much of the refill being exposed.

[0012] Therefore, by delaying the timing of refill delivery by the refill delivery mechanism and reducing the frequency, a longer refill delivery can be performed after the refill is more worn out, thus preventing the actual failure to deliver the refill due to errors.

[0013] The object of this invention is to provide an automatic pencil that has a lead delivery mechanism that can more reliably deliver the lead. [Technical means to solve the problem]

[0014] A mechanical pencil provided according to a certain aspect of the present invention is characterized by comprising: a ball chuck that allows the lead to move forward and prevents it from moving backward; a rotary drive mechanism having a rotor that is driven to rotate in one direction by a backward movement in the axial direction caused by writing pressure received by the lead held by the ball chuck and a forward movement in the axial direction caused by the release of writing pressure; a feed cam surface having an annular cam surface and an axial drop provided on the annular cam surface; an input member that rotates in response to the rotary drive force of the rotor; and an output member. The component comprises: an abutting member abutting against the aforementioned delivery cam surface, and a sliding member having a retaining chuck for holding the pen refill. The abutting member moves along the aforementioned delivery cam surface according to the rotation of the aforementioned output member. By the forward movement of the aforementioned sliding member when the abutting member falls into the aforementioned drop, the pen refill held by the aforementioned retaining chuck is pulled out by the aforementioned ball chuck. It also has a clutch mechanism that transmits the rotational motion of the aforementioned input member to the aforementioned output member, such that when the aforementioned input member rotates only a first rotation angle, the aforementioned output member rotates only a second rotation angle smaller than the aforementioned first rotation angle.

[0015] The aforementioned clutch mechanism can also be a meshing clutch or a friction clutch. The aforementioned clutch mechanism can also be a meshing clutch, with an input cam surface formed on the input member and an output cam surface facing the input cam surface on the output member. Only during a portion of the rotor's rotational motion are the input cam surface and the output cam surface engaged, and the rotor's rotational motion is transmitted to the output member via the input member. The aforementioned rotary drive mechanism can also have a first cam forming member and a second cam forming member. The rotor is formed into an annular shape, with a first cam surface and a second cam surface formed on one end face and the other end face in the axial direction, respectively. A first fixed cam surface and a second fixed cam surface are formed on the first cam forming member and the second cam forming member, respectively, facing the first cam surface and the second cam surface. This causes the ball chuck to retract due to the writing pressure, with the first cam surface of the rotor abutting and meshing with the first fixed cam surface. Upon release of the writing pressure, the aforementioned ball chuck retracts. The second cam surface abuts and engages with the aforementioned second fixed cam surface. When the aforementioned first cam surface of the rotor is engaged with the aforementioned first fixed cam surface, the aforementioned second cam surface and the aforementioned second fixed cam surface of the rotor are set to be phase-shifted relative to one tooth of the cam in the axial direction. The cam spacing in the aforementioned clutch mechanism is set to be smaller than the cam spacing in the aforementioned rotary drive mechanism. The aforementioned ball chuck can also be configured to rotate by receiving the rotary driving force of the aforementioned rotor, thereby rotating the pen refill. A viscous fluid that restricts the movement of the aforementioned output member in the axial direction can also be disposed between the aforementioned output member and the shaft cylinder. The pen refill delivery amount can also be adjusted by adjusting the height of the aforementioned drop. The device may further include a first cam member in the shape of an annular or cylindrical shape, and a second cam member in the shape of an annular or cylindrical shape disposed radially outside the first cam member. The first cam member and the second cam member may cooperate to form the aforementioned delivery cam surface. The height of the aforementioned drop may also be adjusted by rotating the first cam member and the second cam member relative to each other around a central axis. [The effects of the invention]

[0016] According to the present invention, it is possible to achieve the common effect of providing a mechanical pencil that has a lead delivery mechanism that can deliver the lead more reliably. Simple Explanation of the Diagram

[0017] [Figure 1] is a longitudinal sectional view of a mechanical pencil according to an embodiment of the present invention. [Figure 2] is a three-dimensional view of a mechanical pencil. [Figure 3] is an enlarged cross-sectional view of the front half of a mechanical pencil. [Figure 4] is an enlarged cross-sectional view of the rear half of a mechanical pencil. [Figure 5] is a three-dimensional diagram illustrating the internal structure of a mechanical pencil. [Figure 6] is an exploded perspective view of the clutch mechanism. [Figure 7] is an enlarged sectional view of the rotary drive mechanism. [Figure 8] is a schematic diagram illustrating the rotational drive of the rotor in the rotary drive mechanism. [Figure 9] is a schematic diagram illustrating the rotational drive of the rotor, continuing from Figure 8. [Figure 10] is a perspective view of the turntable cam component. [Figure 11] is a perspective view of the rail cam component. [Figure 12] shows other perspective views of the rail cam component. [Figure 13] is a perspective view of the combined rotary cam component and the rail cam component. [Figure 14] shows other perspective views of the assembled turntable cam assembly and the rail cam assembly. [Figure 15] shows a schematic diagram of the feed cam surface. [Figure 16] is a perspective view of the input clutch cam. [Figure 17] is a perspective view of the output clutch cam. [Figure 18] is an enlarged perspective view illustrating the cams of the input clutch cam and the output clutch cam. [Figure 19] is a schematic diagram illustrating the operation of a clutch mechanism that cooperates with a rotary drive mechanism. [Figure 20] is a longitudinal sectional view of the core delivery component. [Figure 21] is an enlarged cross-sectional view of a mechanical pencil to illustrate the lead feeding process. [Figure 22] is an enlarged perspective view of the lid. [Figure 23] is an enlarged perspective view of the shaft cylinder. [Figure 24] is a three-dimensional view of the clamp. [Figure 25] is a longitudinal sectional view of the clamp. Implementation

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Common reference numerals are used to denote corresponding constituent elements throughout the drawings.

[0019] Figure 1 is a longitudinal sectional view of the mechanical pencil 1 according to an embodiment of the present invention; Figure 2 is a perspective view of the mechanical pencil 1; Figure 3 is an enlarged sectional view of the front half of the mechanical pencil 1; Figure 4 is an enlarged sectional view of the rear half of the mechanical pencil 1; Figure 5 is a perspective view illustrating the internal structure of the mechanical pencil 1; and Figure 6 is an exploded perspective view of the clutch mechanism 60.

[0020] The mechanical pencil 1 has: a front shaft 2; a rear shaft 3 that screws onto the outer peripheral surface of the rear end of the front shaft 2; and a tip member 4 that screws onto the outer peripheral surface of the front end of the front shaft 2. The front shaft 2 and the rear shaft 3 constitute a cylinder 6. Alternatively, the tip member 4 may also be included and referred to as the cylinder 6. As described later, the mechanical pencil 1 has a lead 7 protruding from the front end of the slider 9. In this specification, in the axial direction of the mechanical pencil 1, the side with the lead 7 is defined as the "front" side, and the side opposite to the side with the lead 7 is defined as the "rear" side.

[0021] Referring to Figure 3, inside the front end of the shaft cylinder 6, the slider 9 can slide in the axial direction and is configured to rotate about the axis. The slider 9 is a cylindrical shape with its outer diameter tapering towards the front. A flange 9a is provided on the outer peripheral surface of the rear end of the slider 9. The pen refill 7 is guided by the slider 9 and can protrude from the front end of the slider 9. Inside the slider 9, a retaining clip 10 with a through hole 10a formed in the center is disposed. The through hole 10a of the retaining clip 10 is in sliding contact with the outer peripheral surface of the pen refill 7, temporarily holding the pen refill 7.

[0022] On the outer peripheral surface of the slide 9, the rotary cam member 50, which is formed into a cylindrical first cam member, and the rail cam member 52, which is formed into an annular second cam member, are arranged in an axial direction aligned. A slightly cylindrical gripping part 8 is provided at the front end of the pen tip member 4 and on the outer peripheral surface of the rotary cam member 50. The front end of the slide 9 protrudes from the hole at the front end of the rotary cam member 50. A ball bearing clip 11 that holds the pen refill 7 is fitted into the inner peripheral surface of the rear end of the slide 9, specifically a clamping fastener 13.

[0023] The ball chuck 11 includes: a cylindrical clamping device 13, a chuck body 14 disposed within the clamping device 13, a cylindrical chuck retaining portion 15, and a plurality of balls 16. The inner circumferential surface of the clamping device 13 forms a widened conical surface facing forward. The chuck body 14 has a through hole for a pen refill 7 formed along its central axis, and the front end of the chuck body 14 is divided into a plurality of sections along the axial direction. The rear end of the chuck body 14 is held by the chuck retaining portion 15. The chuck body 14 and the chuck retaining portion 15 are movable relative to the clamping device 13 in the axial direction. The plurality of balls 16 are disposed between the inner circumferential surface of the clamping device 13 and the outer circumferential surface of the chuck body 14.

[0024] When writing pressure is applied to the pen refill 7, the pen refill 7 is held by the pen refill 7 because the clip body 14 and the ball bearing 16 abut against the conical surface inside the cylindrical clamp 13. This prevents the pen refill 7 from retracting. On the other hand, when a force is applied to pull the pen refill 7 forward, the pen refill 7 can be pulled forward without resistance because the clip body 14 is not affected by the clamp 13. In other words, the ball bearing 11 allows the pen refill 7 to move forward and prevents it from retracting.

[0025] A coil spring 17 is arranged to surround the clip body 14. The rear end of the coil spring 17 fits into the outside of the clip body 14, and the front end of the coil spring 17 is supported by a section formed on the inner circumferential surface of the clamp 13. The coil spring 17 pushes the clip body 14 rearward, thereby allowing the ball bearing 11 to maintain the grip on the pen refill 7. A cam abutment spring 18, which serves as the coil spring, is arranged to surround the clamp 13. The cam abutment spring 18 pushes the slider 9 forward. The front end of the core box 19 fits into the outer circumferential surface of the rear end of the clip holding portion 15. The core box 19 is cylindrical and houses the pen refill 7 inside.

[0026] The ball chuck 11 is connected to the input clutch cam 61 of the clutch mechanism 60 (described later). That is, the input clutch cam 61 is cylindrical, and the outer peripheral surface of the rear end of the clamping part 13 of the ball chuck 11 fits into the inner peripheral surface of the front end of the input clutch cam 61. The outer peripheral surface of the front end of the cylindrical relay member 12 fits into the inner peripheral surface of the rear end of the input clutch cam 61. The clutch mechanism 60, as described later with reference to Figures 5 and 6, has a forward-protruding abutment member 65c. The abutment member 65c is pushed forward by a cam abutment spring 18 via a slide member 9. Therefore, the slide member 9, ball chuck 11, relay member 12, input clutch cam 61, and abutment member 65c can move integrally in the axial direction within the cylinder 6. The rear end of the relay member 12 is connected to the rotary drive mechanism 30 (described later).

[0027] Referring to Figure 4, at the rear end of the shaft cylinder 6, a pressing rod 20, serving as a pressing part, is movably disposed relative to the shaft cylinder 6. The pressing rod 20 is pushed rearward by a coil spring 21. A partition portion 20a with a refill hole for the pen refill 7 is formed near the rear end of the pressing rod 20. An eraser 22 is detachably mounted inside the rear end of the pressing rod 20. A pressing cap 23 is detachably mounted on the outer peripheral surface of the rear end of the pressing rod 20 to protect the eraser 22 from contamination. The pressing rod 20 fits into the outer peripheral surface of the rear end of the core box 19.

[0028] By pressing the pressing rod 20 or the pressing cover 23 forward, the core cartridge 19 is moved forward. This pushes the chuck body 14 forward via the chuck holding part 15. At the same time, the pen core 7 held by the chuck body 14 also moves forward, thus pushing the pen core 7 out of the slider 9.

[0029] If the pressing operation is released, the pressing rod 20 retracts to its original position by the spring force of the coil spring 21. At this time, the chuck body 14 retracts by the spring force of the coil spring 17. On the other hand, since the pen refill 7 is held by the retaining chuck 10 disposed in the slider 9, the pen refill 7 is pulled out from the chuck body 14 without resistance as the ball bearing chuck 11 acts. As a result, since the pen refill 7 is fed out from the slider 9, the pen refill 7 can be fed out in a predetermined amount with each repeated pressing operation. If the pressing operation is maintained to keep the pressing rod 20 in the forward state, the chuck body 14 protrudes from the clamp 13, and the grip on the pen refill 7 is released. In this state, the pen refill 7, which has been fed out from the slider 9, can be pushed back with fingertips or the like.

[0030] Figure 7 is an enlarged sectional view of the rotary drive mechanism 30. The rotary drive mechanism 30 is disposed within the internal space of the rear axle 3. The rotary drive mechanism 30 is connected to the rear end of the relay member 12. A shaft spring 31 is disposed between the rear end face of the front axle 2 and the front end face of the rotary drive mechanism 30, which pushes the rotary drive mechanism 30 rearward. The rearward movement of the rotary drive mechanism 30 caused by the pushing force of the shaft spring 31 is constrained by the rear end face of the rotary drive mechanism 30 abutting against a section provided on the inner surface of the shaft cylinder 6. The core box 19 passes through the interior of the relay member 12 and the rotary drive mechanism 30, and is separate from the rotary drive mechanism 30.

[0031] The rotary drive mechanism 30 includes: a rotor 40 formed into a cylindrical shape, an upper cam forming member 41 which is a first cam forming member formed into a cylindrical shape, a lower cam forming member 42 which is a second cam forming member formed into a cylindrical shape, a cylindrical member 43 formed into a cylindrical shape, a torque eliminator 44 formed into a cylindrical shape, and a helical buffer spring 45. The rotary drive mechanism 30 is modularized by forming these components as a single unit.

[0032] The outer peripheral surface of the rear end of the relay member 12 fits into the inner peripheral surface of the front end of the rotor 40. Near the front end of the rotor 40, there is a portion with a flange formed with a slightly larger diameter. A first cam surface 40a is formed on the rear end surface of this portion, and a second cam surface 40b is formed on the front end surface of this portion.

[0033] The upper cam forming member 41 is located behind the first cam surface 40a of the rotor 40 and rotatably surrounds the rotor 40. The lower cam forming member 42 is fitted onto the outer peripheral surface of the front end of the upper cam forming member 41. A first fixed cam surface 41a, serving as a first fixed cam surface, is formed on the front end face of the upper cam forming member 41, which faces the first cam surface 40a of the rotor 40. A second fixed cam surface 42a, serving as a second fixed cam surface, is formed on the inner surface of the front end of the lower cam forming member 42, which faces the second cam surface 40b of the rotor 40.

[0034] A cylindrical member 43, formed into a cylindrical shape, is fitted onto the outer peripheral surface of the rear end of the upper cam forming member 41. A through hole 43a, through which a core box 19 can be inserted, is formed at the rear end of the cylindrical member 43. A cylindrical torque eliminator 44, movable in the axial direction, is disposed within the cylindrical 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 cylindrical member 43. The buffer spring 45 pushes the rotor 40 forward via the torque eliminator 44.

[0035] Here, the relay component 12 transmits the backward and forward movements (buffering movements) of the pen refill 7 according to the writing action to the rotary drive mechanism 30, that is, to the rotor 40, and at the same time, transmits the rotational motion of the rotor 40 in the rotary drive mechanism 30 generated by the buffering movement to the ball chuck 11 which is holding the pen refill 7. Therefore, the pen refill 7 held by the ball chuck 11 also rotates.

[0036] Except when writing with the mechanical pencil 1, that is, when no writing pressure is applied to the lead 7, the rotor 40 is positioned in front by the spring force of the buffer spring 45 via the torque canceller 44. Therefore, the second cam surface 40b of the rotor 40 abuts against the second fixed cam surface 42a and is engaged. When writing with the mechanical pencil 1, that is, when writing pressure is applied to the lead 7, the ball chuck 11 retracts against the spring force of the buffer spring 45, and the rotor 40 retracts accordingly. Therefore, the first cam surface 40a of the rotor 40 abuts against the first fixed cam surface 41a and is engaged.

[0037] Figure 8 is a schematic diagram illustrating the rotational driving action of the rotor 40 of the mechanical pencil 1 in Figure 1, and Figure 9 is a schematic diagram continuing the illustration of the rotational driving action of the rotor 40 from Figure 8. In Figures 8 and 9, on the rear end face of the upper side of the rotor 40, a first cam surface 40a, which is continuously serrated in the circumferential direction, is formed into an annular shape; on the front end face of the lower side of the rotor 40, a second cam surface 40b, which is also continuously serrated in the circumferential direction, is formed into an annular shape.

[0038] A first fixed cam surface 41a, which is continuously serrated along the circumferential direction, is also formed on the annular end face of the upper cam forming member 41, which faces the first cam surface 40a of the rotor 40. A second fixed cam surface 42a, which is continuously serrated along the circumferential direction, is also formed on the annular end face of the lower cam forming member 42, which faces the second cam surface 40b of the rotor 40. The cam surfaces formed on the first cam surface 40a and the second cam surface 40b of the rotor 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, have almost the same spacing between them.

[0039] Figure 8(A) shows the relationship between the rotor 40, the upper cam forming member 41, and the lower cam forming member 42 when no writing pressure is applied to the pen refill 7. In this state, the second cam surface 40b formed on the rotor 40 engages with the second fixed cam surface 42a of the lower cam forming member 42 by the spring force of the buffer spring 45. At this time, the first cam surface 40a of the rotor 40 and the first fixed cam surface 41a of the upper cam forming member 41 are set to be offset by half a phase (half a pitch) relative to one tooth of the cam in the axial direction.

[0040] Figure 8(B) shows the initial state in which writing pressure is applied to the lead 7 for writing with the mechanical pencil 1. In this state, the rotor 40 retracts as the ball chuck 11 retracts, causing the buffer spring 45 to contract. As a result, the rotor 40 moves to the side of the first fixed cam surface 41a of the upper cam forming member 41.

[0041] Next, Figure 8(C) shows a state where writing pressure is further applied to the pen refill 7, causing the rotor 40 to abut against the first fixed cam surface 41a of the upper cam forming member 41 and retract. In this state, the first cam surface 40a of the rotor 40 engages with the first fixed cam surface 41a of the upper cam forming member 41. Thus, the rotor 40 receives a rotational drive corresponding to half a phase (half a pitch) of a tooth on the first cam surface 40a.

[0042] Furthermore, the triangular markings at the center of the rotor 40 in Figures 8 and 9 are used to indicate the amount of rotational movement of the rotor 40. Moreover, in the state shown in Figure 8(C), the second cam surface 40b of the rotor 40 and the second fixed cam surface 42a of the lower cam forming member 42 are set to be offset by half a phase (half a pitch) relative to one tooth of the cam in the axial direction.

[0043] Next, Figure 9(D) shows the initial state after the writing of the mechanical pencil 1 has ended and the writing pressure on the lead 7 has been released. At this time, the rotor 40 moves forward by the spring force of the buffer spring 45. As a result, the rotor 40 moves towards the lower cam forming member 42.

[0044] Next, Figure 9(E) shows the rotor 40 advancing by the spring force of the buffer spring 45 against the second fixed cam surface 42a of the lower cam forming member 42. At this time, the second cam surface 40b of the rotor 40 engages with the second fixed cam surface 42a of the lower cam forming member 42. Thus, the rotor 40 again receives a rotational drive corresponding to half a phase (half a pitch) of a tooth on the second cam surface 40b.

[0045] Therefore, as shown by the triangular mark in the center of the rotor 40, the rotor 40, in its reciprocating motion along the axial direction due to writing pressure, receives rotational drive from a tooth (1 pitch) corresponding to the first cam surface 40a and the second cam surface 40b, and the pen refill 7, held by the ball bearing chuck 11, is also rotated. Thus, the rotor 40, through one reciprocating motion along the axial direction caused by writing, receives rotational motion from a tooth of the corresponding cam, and by repeating this action, the pen refill 7 is sequentially rotated. Therefore, uneven wear of the pen refill 7 during continuous writing can be prevented, and large variations in the thickness or density of the lines can be prevented.

[0046] In summary, the rotary drive mechanism has a first cam forming member and a second cam forming member. The rotor is formed into an annular shape, with a first cam surface and a second cam surface formed on one end face and the other end face in the axial direction, respectively. A first fixed cam surface and a second fixed cam surface are formed on the first cam forming member and the second cam forming member, respectively, in a manner that opposes the first cam surface and the aforementioned second cam surface. The first cam surface of the rotor abuts and engages with the first fixed cam surface due to the retraction action of the ball chuck caused by writing pressure. When the writing pressure is released, the second cam surface of the rotor abuts and engages with the second fixed cam surface. When the first cam surface of the rotor is engaged with the first fixed cam surface, the second cam surface of the rotor and the second fixed cam surface are set to be phase-shifted relative to one tooth of the cam in the axial direction. When the second cam surface of the rotor is engaged with the second fixed cam surface, the first cam surface of the rotor and the first fixed cam surface are set to be phase-shifted relative to one tooth of the cam in the axial direction.

[0047] Furthermore, the torque eliminator 44, which receives the spring force from the buffer spring 45 and pushes the rotor 40 forward, slides between its front end face and the rear end face of the rotor 40 to prevent the rotational motion of the rotor 40 from being transmitted to the buffer spring 45. That is, by preventing the rotational motion of the rotor 40 from being transmitted to the buffer spring 45 through the torque eliminator 44, the reverse torsion (torque) of the buffer spring 45, which hinders the rotational motion of the rotor 40, is prevented from occurring.

[0048] Based on the above, the mechanical pencil 1 has a ball chuck 11 and a rotor 40, and is configured to release and hold the lead 7 by moving the ball chuck 11 back and forth, so that the lead 7 can be sent forward. The ball chuck 11 is held in the cylinder 6, so that it can rotate around the central axis when holding the lead 7. Furthermore, the rotor 40 is rotated by moving the ball chuck 11 back and forth due to the writing pressure of the lead 7, and the rotational motion of the rotor 40 is transmitted to the lead 7 through the ball chuck 11.

[0049] Referring to Figures 10 to 14, the refill feeding mechanism and the feeding amount adjustment mechanism will be described. The refill feeding mechanism receives the rotational driving force of the rotor 40 of the rotational drive mechanism 30, which in turn feeds the pen refill 7 out of the slider 9.

[0050] Figure 10 is a perspective view of the rotary cam member 50. In Figure 10, the rotary cam member 50 is positioned above the mechanical pencil 1, behind it. The rotary cam member 50 is a cylindrical member and includes: a cam body 50a, a flange 50b formed on the outer peripheral surface of the cam body 50a, a mating protrusion 50c formed on the rear end face of the flange 50b, and a rotary cam 51 formed on the rear end face of the cam body 50a. The rotary cam 51 has: a flat first annular cam surface 51a located further forward and orthogonal to the central axis, and a flat second annular cam surface 51b located further rearward and orthogonal to the central axis. Furthermore, the two ends of the first annular cam surface 51a and the second annular cam surface 51b are connected by a longitudinal wall 51c.

[0051] Figure 11 is a perspective view of the track cam member 52, and Figure 12 is another perspective view of the track cam member 52. In Figures 11 and 12, the track cam member 52 is positioned above the mechanical pencil 1, behind it. The track cam member 52 is a ring-shaped member. An adjustment recess 52a is formed on the front end face of the track cam member 52. A plurality of fitting recesses 52b, evenly spaced along the circumference, are formed on the bottom surface of the adjustment recess 52a.

[0052] A track cam 53 is formed on the rear end face of the track cam member 52. The track cam 53 has: a flat first annular cam surface 53a located further forward and orthogonal to the central axis; a flat second annular cam surface 53b located further rearward and orthogonal to the central axis; and an inclined surface 53c of the annular cam surface, which is arranged to gradually rise circumferentially to connect one end of the first annular cam surface 53a and the second annular cam surface 53b. The other ends of the first annular cam surface 53a and the second annular cam surface 53b are connected by a longitudinal wall 53d.

[0053] Figure 13 is a perspective view of the assembled rotary cam member 50 and the rail cam member 52, and Figure 14 is another perspective view of the assembled rotary cam member 50 and the rail cam member 52. In Figures 13 and 14, the rotary cam member 50 and the rail cam member 52 are positioned so that they are positioned above the rear side of the mechanical pencil 1. The annular rail cam member 52 is inserted into the rear end of the cam body 50a of the rotary cam member 50 and is engaged by the flange portion 50b. That is, the front end face of the rail cam member 52 abuts against the rear end face of the flange portion 50b of the rotary cam member 50. At this time, the engaging protrusion 50c provided on the flange portion 50b of the rotary cam member 50 engages with any one of the engaging recesses 52b of the adjusting recess 52a of the rail cam member 52. The rail cam member 52 is positioned radially outward of the rotary cam member 50.

[0054] With the rotary cam component 50 and the rail cam component 52 combined, the rotary cam 51 of the rotary cam component 50 is positioned near the rail cam 53 of the rail cam component 52. In this way, the rotary cam 51 and the rail cam 53 cooperate to form a continuous, i.e., annular, delivery cam surface 54 in the circumferential direction.

[0055] As shown in Figure 3, the rotary cam member 50 and the rail cam member 52 are combined and positioned on the outside of the slide member 9. A portion of the rotary cam member 50 and the rail cam member 52 are covered by the pen tip member 4 and the grip portion 8 on their outer peripheral surfaces. The grip portion 8 engages with the outer peripheral surface of the rotary cam member 50, thus allowing them to rotate together around the central axis. A coil spring 56 is positioned between the inner surface of the front end of the pen tip member 4 and the flange portion 50b of the rotary cam member 50. Furthermore, the slide member 9 maintains contact with the delivery cam surface 54 by the forward-pushing abutment member 65c, which is pushed forward by the cam abutment spring 18. The outer peripheral surface of the rail cam member 52 engages with the inner peripheral surface of the pen tip member 4, thereby constraining the rotation of the pen tip member 4 and even the shaft cylinder 6 of the rail cam member 52.

[0056] The shape of the cam surface 54 can be changed by rotating the turntable cam member 50 and the guide cam member 52 relative to each other around the central axis. Specifically, the user holds the shaft cylinder 6 with one hand and rotates the grip part 8 with the other hand, causing the turntable cam member 50 to rotate around the central axis. Since the guide cam member 52 engages with the shaft cylinder 6, the turntable cam member 50 rotates relative to the guide cam member 52 around the central axis. The rotation of the turntable cam member 50 relative to the guide cam member 52 is performed gradually by the engagement protrusion 50c of the turntable cam member 50 moving and engaging between the adjacent engagement recesses 52b of the corresponding guide cam member 52. Therefore, the rotation of the turntable cam member 50 relative to the guide cam member 52 around the central axis is performed gradually by the engagement protrusion 50c of the turntable cam member 50 within the range of the adjustment recesses 52a of the movable guide cam member 52. The relative positions of the rotary cam 51 of the rotary cam 50 and the rail cam 53 of the rail cam 52 change according to the position of the engaging protrusion 50c of the rotary cam member 50 engaging the engaging recess 52b of the rail cam member 52. As a result, the shape of the delivery cam surface 54 can be changed. The rotary cam member 50 is pushed against the rail cam member 52 by the coil spring 56, and a pressing sensation can be obtained when the rotary cam member 50 rotates gradually relative to the rail cam member 52.

[0057] Next, referring to Figure 15, the delivery of the pencil lead 7 caused by the delivery cam surface 54 will be explained. Figure 15 shows a schematic diagram of the delivery cam surface 54. Figure 15 is a circumferentially unfolded cylindrical surface including the delivery cam surface 54 around the central axis to show the positional relationship between the turntable cam member 50 and the rail cam member 52. The rear side of the mechanical pencil 1 is shown at the top of Figure 15.

[0058] Referring to Figure 15, the turntable cam member 50 is positioned relative to the rail cam member 52 by arranging the longitudinal wall 51c of the turntable cam 51 and the inclined surface 53c of the rail cam 53 in a radially overlapping manner. In Figure 15, the line (surface) located further rearward of the turntable cam 51 and the rail cam 53, that is, located higher in the figure, constitutes the delivery cam surface 54. That is, the second annular cam surface 51b of the turntable cam 51 and the second annular cam surface 53b and inclined surface 53c of the rail cam 53 cooperate to form the delivery cam surface 54. Furthermore, in the delivery cam surface 54, the height (height difference) of the step difference 55 (drop) formed by the second annular cam surface 51b of the turntable cam 51 and the inclined surface 53c of the rail cam 53 in the axial direction is defined as the step height H.

[0059] With the longitudinal wall 51c of the turntable cam 51 positioned on the side of the first annular cam surface 53a of the guide cam 53, the turntable cam member 50 and the guide cam member 52 can rotate relative to each other around the central axis, resulting in a higher step height H. Conversely, with the longitudinal wall 51c of the turntable cam 51 positioned on the opposite side of the first annular cam surface 53a of the guide cam 53, the turntable cam member 50 and the guide cam member 52 can rotate relative to each other around the central axis, resulting in a lower step height H.

[0060] The rotor 40 of the rotary drive mechanism 30 is driven to slowly rotate the abutment 65c according to the buffering action of the pen refill 7, as described later. That is, when viewed with the front end of the slider 9 in front, the abutment 65c rotates to the right about the central axis. By this rotational movement, the abutment 65c, which is pushed forward by the cam abutment spring 18, moves circumferentially in cooperation with the delivery cam surface 54. That is, after the abutment 65c moves from right to left in Figure 15, it moves in a manner that slowly climbs along the inclined surface 53c of the turntable cam 51 that constitutes the delivery cam surface 54.

[0061] When the abutment 65c reaches the step 55, it is pressed down by the spring force of the cam abutment spring 18 and falls into the step 55. That is, the abutment 65c moves forward only by the step height H of the step 55 from the second annular cam surface 51b of the turntable cam 51. At this time, the slide 9 and the retaining chuck 10 disposed inside the slide 9 also move forward together with the forward movement of the abutment 65c. As a result, the pen refill 7 held by the retaining chuck 10 is pulled out from the ball chuck 11, and is fed out only by the step height H from the front end of the slide 9. Therefore, the amount of pen refill 7 fed out, that is, the amount fed out, is equal to the step height H.

[0062] Through the above actions, the contact 65c can feed the pen refill 7 from the slide 9 with each revolution along the feed cam surface 54. By repeating this action, the pen refill 7 is worn down as the writing action progresses and is fed out sequentially.

[0063] In other words, in the refill delivery mechanism, the contact member 65c moves along the delivery cam surface 54 according to the rotation of the rotor 40. The forward movement of the slide member 9 when the contact member 65c falls into the step 55 of the delivery cam surface 54 constitutes the action of pulling the pen refill 7 held by the holding chuck 10 out of the ball chuck 11. By utilizing the step 55 of the delivery cam surface 54, the refill delivery mechanism can convert the rotational driving force of the rotor 40 in the rotation drive mechanism 30 into the action of delivering the pen refill 7. The term "step" generally refers to the structure that creates a height difference on the delivery cam surface 54.

[0064] The mechanical pencil 1 is driven by the rotational force of the rotor 40 in the rotary drive mechanism 30, which drives the lead 7 held by the ball chuck 11 to rotate as well. Therefore, uneven wear of the lead 7 during continuous writing is prevented, and consequently, significant variations in the thickness or density of the lines are prevented. In other words, the rotary drive mechanism 30 has a rotor 40 that rotates in one direction due to a backward movement in the axial direction caused by the writing pressure received by the lead 7 held by the ball chuck 11 and a forward movement in the axial direction caused by the release of the writing pressure.

[0065] In the feed amount adjustment mechanism, as described above, the step height H of the step 55 in the feed cam surface 54 can be changed by simply rotating the turntable cam member 50 and the rail cam member 52 relative to each other around the central axis. Therefore, the amount of continuous feed of the pen refill 7 caused by the refill feed mechanism can be adjusted more easily and accurately.

[0066] By adjusting the degree of wear of the lead 7 caused by different writing pressures from different users, the hardness of the lead 7 used, and the lead feed amount to be almost consistent, the amount of lead 7 protruding from the slider 9 can be kept constant regardless of the writing action. As a result, the mechanical pencil 1 can write continuously for a long time with a single press. Ideally, the turntable cam 51 or the track cam 53 should be configured with a step height H of a step height H that is equivalent to a length exceeding the normally imagined wear of the lead 7. This allows the lead feed amount to be set to suit the preferences of all users.

[0067] In the above-described embodiment, although the rotary cam member 50, as the first cam member, is cylindrical, it can also be an annular member. Similarly, although the rail cam member 52, as the second cam member, is an annular member, it can also be cylindrical. A rail cam 53 can be provided in the first cam member, and a rotary cam 51 can also be provided in the second cam member. That is, the annular or cylindrical first cam member and the annular or cylindrical second cam member disposed radially outside the first cam member can cooperate to form a delivery cam surface. Furthermore, by moving the first and second cam members relative to each other back and forth, that is, by separating them in the axial direction, the step height can also be adjusted.

[0068] The track cam component 52 and the rotary cam component 50 can be integrated into one unit, or the rotary cam component can consist of only a single feed cam surface 54. In this case, although the feed amount cannot be adjusted as described above, the number of parts is reduced, thus reducing costs. To adjust the feed amount, multiple rotary cam components with various step heights H can also be prepared. In this case, the user can choose to replace the rotary cam component that best suits their needs for achieving the most suitable feed amount.

[0069] Next, the clutch mechanism 60 will be described with reference to Figures 3, 5, 6, and 16 to 19. The clutch mechanism 60 takes the rotational motion of the rotor 40 in the rotary drive mechanism 30 as input and the rotational motion of the abutment member 65c as output. The clutch mechanism 60 includes: an input clutch cam 61 as an input member, an output clutch cam 62 as an output member, a transmission cam 64, and a delivery cam 65. Furthermore, the mechanical pencil 1 also includes a clutch cam retainer 66.

[0070] Figure 16 is a perspective view of the input clutch cam 61, Figure 17 is a perspective view of the output clutch cam 62, and Figure 18 is an enlarged perspective view illustrating the cams 61 and 62. In Figure 16, the input clutch cam 61 is positioned above the rear side of the mechanical pencil 1, and in Figure 17, the output clutch cam 62 is positioned above the rear side of the mechanical pencil 1. In Figure 18, the output clutch cam is positioned above the rear side of the mechanical pencil 1.

[0071] The input clutch cam 61 is a cylindrical component, and a cam protrusion 61a is provided on the annular rear end face 61b that forms the input cam surface. A flange portion 61c is provided on the outer peripheral surface of the rear end of the input clutch cam 61.

[0072] The output clutch cam 62 is positioned behind the input clutch cam 61. The output clutch cam 62 is a cylindrical component, with a flange 62a on its outer peripheral surface near its front end. A clutch cam surface 63, serving as the output cam surface, is provided on the annular front end face of the output clutch cam 62. The clutch cam surface 63 and the cam protrusion 61a of the input clutch cam 61 are positioned opposite each other. The clutch cam surface 63 is formed by a plurality of hills 63a and a plurality of valleys 63b, each valley having a flat bottom surface located between adjacent hills 63a.

[0073] Referring to Figure 18, the cam protrusion 61a of the input clutch cam 61 and the ridge 63a of the output clutch cam 62 have approximately the same shape. The cam protrusion 61a of the input clutch cam 61 has a first engagement surface 61aa that is approximately perpendicular to the rear end face 61b and a first inclined surface 61ab. Similarly, the ridge 63a of the output clutch cam 62 has a second engagement surface 63aa that is approximately perpendicular to the bottom surface of the trough 63b and a second inclined surface 63ab. As will be described later, during the operation of the clutch mechanism 60, the input clutch cam 61 and the output clutch cam 62 cooperate by engaging the first engagement surface 61aa of the input clutch cam 61 and the second engagement surface 63aa of the output clutch cam 62.

[0074] Referring to Figures 3, 5, and 6, the rear end of the transmission cam 64 engages with the outer peripheral surface of the front end of the output clutch cam 62. The transmission cam 64 is formed by inserting its rear end face into and abutting against the flange 62a of the output clutch cam 62. The transmission cam 64 is cylindrical, and its front end face has first engaging protrusions 64a extending forward and evenly spaced along the circumference. A first engaging wall 64b extending along the axial direction is provided on the circumferential side of the first engaging protrusions 64a. An annular protrusion 64c is provided on the inner peripheral surface of the transmission cam 64.

[0075] The input clutch cam 61 is disposed within the transmission cam 64, while the flange portion 61c is disposed between the clutch cam surface 63 of the output clutch cam 62 and the annular protrusion 64c of the transmission cam 64. That is, the forward movement of the input clutch cam 61 is constrained by the flange portion 61c engaging with the annular protrusion 64c of the transmission cam 64. The retraction of the input clutch cam 61 is constrained by the cooperation of the cam protrusion 61a and the clutch cam surface 63 of the output clutch cam 62.

[0076] A feed cam 65 is disposed in front of the transmission cam 64. The feed cam 65 is cylindrical and has a second engaging protrusion 65a extending rearward and evenly spaced along the circumference on its rear end face. The second engaging protrusion 65a has a shape complementary to the first engaging protrusion 64a of the transmission cam 64. A second engaging wall 65b is provided along the axial direction on the side of the second engaging protrusion 65a in the circumferential direction. A protruding abutment 65c protruding forward as described above is provided on the front end face of the feed cam 65. An annular protrusion 65d is provided on the inner circumferential surface of the front end of the feed cam 65.

[0077] Within the delivery cam 65, the slide member 9 is inserted from the rear, and the flange 9a engages with the annular protrusion 65d of the delivery cam 65. The aforementioned cam abutment spring 18 is configured such that one end engages with the inner surface of the flange 9a of the slide member 9, and the other end engages with the front end face of the input clutch cam 61. The slide member 9 is pushed forward by the spring force of the cam abutment spring 18, and the flange 9a of the pushed slide member 9 pushes the delivery cam 65 forward. As a result, the abutment member 65c is pushed forward by abutting against the delivery cam surface 54 as described above. The delivery cam 65 can move integrally with respect to the slide member 9 in the axial direction, and can rotate independently about the central axis.

[0078] The clutch cam retainer 66 is cylindrical and can be installed on the inner surface of the shaft sleeve 6, specifically relative to the front axle 2. A liquid lubricant, such as a high-viscosity grease, is coated on the inner circumferential surface of the clutch cam retainer 66. The output clutch cam 62 is inserted into the clutch cam retainer 66, thereby filling the space between the outer circumferential surface of the output clutch cam 62 and the inner circumferential surface of the clutch cam retainer 66 with liquid lubricant. As a result, the output clutch cam 62 and the connected transmission cam 64 are loosely held by the clutch cam retainer 66, mitigating rapid axial movement within the shaft sleeve 6 caused by gravity or other factors. Alternatively, the clutch cam retainer 66 can be integrally formed with the shaft sleeve 6. That is, a viscous fluid that inhibits axial movement of the output member is disposed between the output member and the shaft sleeve. By having a clutch cam retainer 66 in the mechanical pencil 1, the effects of dimensional irregularities and frictional resistance of the various parts of the clutch mechanism 60 can be absorbed. Furthermore, the clutch cam retainer 66 can be omitted.

[0079] Referring to Figure 3, as described above, the outer peripheral surface of the rear end of the clamping device 13 of the ball chuck 11 engages with the inner peripheral surface of the front end of the input clutch cam 61, and the outer peripheral surface of the front end of the relay member 12 engages with the inner peripheral surface of the rear end of the input clutch cam 61. The rear end of the relay member 12 is connected relative to the rotor 40 (Figure 4). Therefore, the input clutch cam 61 is rotated and driven by the rotor 40 of the rotary drive mechanism 30 via the relay member 12. Furthermore, the input clutch cam 61 moves back and forth together with the rotor 40 via the relay member 12 according to the buffering action of the pen refill 7. The relay member 12 passes through the interior of the output clutch cam 62 and the transmission cam 64 and is separate from the relay member 12. Therefore, the rotational movement and back and forth movement of the relay member 12 are not directly transmitted to the output clutch cam 62 and the transmission cam 64.

[0080] The rotational motion of the input clutch cam 61 is transmitted to the output clutch cam 62 via the cooperation of the cam protrusion 61a and the clutch cam surface 63 of the output clutch cam 62, as described later with reference to FIG19. The rotational motion of the output clutch cam 62 is transmitted to the delivery cam 65 via the connected transmission cam 64. That is, the first engagement wall 64b of the first engagement protrusion 64a engages circumferentially with the second engagement wall 65b of the second engagement protrusion 65a as the transmission cam 64 rotates, transmitting the rotational motion of the transmission cam 64 to the delivery cam 65. As a result, the abutment 65c moves along the delivery cam surface 54 as described above, thus dispensing the pen refill 7.

[0081] Figure 19 is a schematic diagram illustrating the operation of the clutch mechanism 60 cooperating with the rotary drive mechanism 30. To show the positional relationship between the rotor 40, upper cam forming member 41, and lower cam forming member 42 in the rotary drive mechanism 30, and the input clutch cam 61 and output clutch cam 62 in the clutch mechanism 60, Figure 19 is a circumferentially expanded cylindrical surface containing each cam surface around the central axis. The mechanical pencil 1 is located behind the rotor 40 at the top of Figure 19. The states of the rotary drive mechanism 30 shown in Figures 19(A) to (E) correspond to the states of the rotary drive mechanism 30 shown in Figures 8(A) to (C) and Figures 9(D) and (E), respectively. Each of the rotor 40 and the output clutch cam 62 is marked with a triangle indicating the amount of rotational movement.

[0082] Figure 19(A) shows the relationship between the rotary drive mechanism 30 and the clutch mechanism 60 in the state where no writing pressure is applied to the pen refill 7. The rotary drive mechanism 30 corresponds to the state shown in Figure 8(A). Therefore, the second cam surface 40b of the rotor 40 engages with the second fixed cam surface 42a of the lower cam forming member 42. At this time, the cam protrusion 61a of the input clutch cam 61 and the clutch cam surface 63 of the output clutch cam 62 are separated in the axial direction and do not abut. The triangular markings on each of the rotor 40 and the output clutch cam 62 are arranged on the same straight line in the axial direction.

[0083] Next, Figure 19(B) shows the initial state when writing pressure is applied to the pen refill 7. The rotary drive mechanism 30 corresponds to the state shown in Figure 8(B). Therefore, in this state, while the rotor 40 moves towards the upward cam forming member 41, the input clutch cam 61 approaches the clutch cam surface 63 of the output clutch cam 62. At this time, the first engagement surface 61aa of the cam protrusion 61a of the input clutch cam 61 and the second engagement surface 63aa of the hill 63a of the output clutch cam 62 (Figure 18) are separated circumferentially, specifically, separated only by a distance D1 in the circumferential direction.

[0084] Next, Figure 19(C) shows the state where writing pressure is further applied to the pen refill 7, causing the first cam surface 40a of the rotor 40 to engage with the first fixed cam surface 41a of the upper cam forming member 41. The rotary drive mechanism 30 corresponds to the state shown in Figure 8(C). Therefore, the rotor 40 receives a rotary drive equivalent to half a phase (half a pitch) of one tooth of the first cam surface 40a. That is, the rotor 40 rotates only by a rotation angle equivalent to a circumferential rotational movement distance L1 from the state shown in Figure 19(A). As the rotor 40 rotates, the cam protrusion 61a of the input clutch cam 61 engages with the bevel 63a of the output clutch cam 62, and the output clutch cam 62 is driven by the rotation of the input clutch cam 61. As shown in Figure 19(B) prior to this, since the cam protrusion 61a of the input clutch cam 61 and the bevel 63a of the output clutch cam 62 are circumferentially separated, the rotational movement of the output clutch cam 62 is smaller by a distance L1 than that of the input clutch cam 61, i.e., smaller than that of the rotor 40. Specifically, the rotational movement of the output clutch cam 62 is a distance L1 minus a distance D1, which is a distance L2. Therefore, the output clutch cam 62 only rotates by a second rotation angle equivalent to a distance L2.

[0085] Next, Figure 19(D) shows the initial state after releasing the writing pressure on the pen refill 7. The rotary drive mechanism 30 corresponds to the state shown in Figure 9(D). Therefore, in this state, while the rotor 40 moves towards the lower cam forming member 42 by the spring force of the buffer spring 45, the cam protrusion 61a of the input clutch cam 61 separates from the clutch cam surface 63 of the output clutch cam 62.

[0086] Next, Figure 19(E) shows the state in which the second cam surface 40b of the rotor 40 engages with the second fixed cam surface 42a of the lower cam forming member 42 by the spring force of the buffer spring 45. The rotary drive mechanism 30 corresponds to the state shown in Figure 9(E). Therefore, the rotor 40 again receives a rotary drive corresponding to half a phase (half a pitch) of one tooth of the second cam surface 40b. That is, the rotor 40, and the input clutch cam 61 connected to the rotor 40, rotates only by a first rotation angle corresponding to a rotational movement of a distance L3 equivalent to one phase (one pitch) from the state shown in Figure 19(A). On the other hand, since the cam protrusion 61a of the input clutch cam 61 and the ridge 63a of the output clutch cam 62 are separated in the axial direction, the first engagement surface 61aa of the input clutch cam 61 and the second engagement surface 63aa of the output clutch cam 62 will not engage, so the output clutch cam 62 will not be rotary driven. Furthermore, the input clutch cam 61 and the output clutch cam 62 are configured to cooperate only on the first engagement surface 61aa of the input clutch cam 61 and the second engagement surface 63aa of the output clutch cam 62, and will not cooperate in other parts.

[0087] By writing, the rotor 40 moves back and forth once in the axial direction. Although the rotor 40 and the input clutch cam 61 rotate corresponding to one tooth of the cam in the rotary drive mechanism 30, the output clutch cam 62 rotates by a smaller amount. That is, the clutch mechanism 60 is configured such that when the input clutch cam 61 rotates only a first rotation angle, the output clutch cam 62 rotates only a second rotation angle smaller than the first rotation angle, thus transmitting the rotational motion of the input clutch cam 61 to the output clutch cam 62. The spacing between the cams in the clutch mechanism 60 is set to be smaller than the spacing between the cams in the rotary drive mechanism 30. Specifically, the output clutch cam 62 is only rotated by the difference between the rotation angle of one tooth of the cam in the rotary drive mechanism 30 (the first rotation angle) and the rotation angle of one tooth of the cam in the clutch mechanism 60 (the second rotation angle).

[0088] For example, the number of teeth A of the rotation drive mechanism 30, such as the first cam surface 40a of the rotor 40, is set to 40, and the number of teeth B of the clutch cam surface 63 of the output clutch cam 62 is set to 46. The number of forward and backward movements required for the rotor 40 to rotate one revolution, i.e., the number of strokes in writing, is 40. Since the rotation angle C of the rotor 40 for each stroke is 360 / A, then 360 / 40 = 9 degrees. Since the rotation angle D corresponding to the distance between the adjacent cam 63a of the output clutch cam 62 is 360 / D, then 360 / 46 = 7.83 degrees. Thus, as explained with reference to Figure 19, since the rotation angle E of the output clutch cam 62 for each stroke is CD, it forms 9 - 7.83 = 1.17 degrees. Therefore, the number of strokes required for the output clutch cam 62 to rotate one revolution is 360 / 1.17 = 307.7 strokes, or 308 strokes. When expressed in terms of reduction ratio, this is 1 / (C / E) = 1 / 7.69.

[0089] According to the clutch mechanism 60, compared to the number of strokes required for the rotor 40 to rotate one revolution (e.g., 40 strokes), the number of strokes required for the output clutch cam 62, and even the abutment member 65c of the delivery cam 65 to rotate one revolution (e.g., 308 strokes) can be increased. Furthermore, by adjusting the number of teeth A of the cam of the rotary drive mechanism 30 and / or the number of teeth B of the cam of the clutch mechanism 60, the rotor 40 can rotate one revolution using any number of strokes, while the pen refill can be delivered using any number of strokes.

[0090] The output clutch cam 62 and the transmission cam 64 can also be integrally formed. Alternatively, the output clutch cam 62, the transmission cam 64, and the delivery cam 65 can be formed together as an output component. The slider 9 and the delivery cam 65 can also be integrally formed. The input clutch cam 61, as the input cam surface, has one cam protrusion 61a, but it can also have multiple cam protrusions 61a. The clutch cam surface 63, which is the input cam surface of the input clutch cam 61 and the output cam surface of the output clutch cam 62, can be arbitrarily formed as the first engagement surface 61aa and the second engagement surface 63aa, as long as engagement occurs in circumferential movement and not in axial movement. Similarly, the transmission cam 64 and the delivery cam 65 can be arbitrarily formed as the first engagement wall 64b and the second engagement wall 65b, as long as engagement occurs in circumferential movement and not in axial movement.

[0091] In the above-described embodiment, the so-called input clutch cam 61 and output clutch cam 62 are respectively used as the input member and output member. That is, the clutch mechanism 60 has an input cam surface formed on the input member and an output cam surface formed on the output member that faces the input cam surface. The input cam surface and the output cam surface engage only during part of the rotor's rotational motion, transmitting the rotor's rotational motion to the output member via the input member.

[0092] However, a friction clutch can also be used as the clutch mechanism. That is, circular or conical components are placed opposite each other as input and output components. Through friction, the rotational motion of the rotor 40 via the relay component 12 is such that when the input component rotates only a first rotation angle, the output component rotates only a second rotation angle smaller than the first rotation angle. By changing the shape, material, surface roughness, etc., of the contact surface between the opposing circular or conical components and adjusting the applied friction, the rotation angle transmitted from the input component to the output component can also be adjusted. In this way, the pen refill can be delivered with any number of strokes while the rotor 40 rotates once. For example, rubber, sandpaper, etc., can be used to form the contact surface between the input and output components. In addition to engagement clutches and friction clutches, any other clutch mechanism can be used.

[0093] In the above embodiment, because the ball chuck 11 is connected to the input clutch cam 61, the ball chuck 11 receives the rotational driving force of the rotor 40 via the relay member 12 and the input clutch cam 61, thus causing the lead 7 to rotate. However, the ball chuck 11 and the input clutch cam 61 may not be connected. That is, the clutch mechanism can also be applied to mechanical pencils that do not cause the lead to rotate.

[0094] After the pen refill 7 is pulled out from the ball chuck 11 by pressing or by the refill delivery mechanism, and before writing pressure is applied to the pen refill 7, the pen refill has room to retract further (hereinafter referred to as "gap"). Therefore, if the actual amount of pen refill 7 delivered is small, the pen refill 7 delivered through the gap will retract, and there may actually be a situation where the pen refill 7 is not delivered at all.

[0095] The clutch mechanism delays the timing or frequency of lead delivery caused by the lead delivery mechanism. Therefore, the clutch mechanism allows for more lead delivery even after the lead is more worn, and the gap effectively prevents lead delivery from being missed. The lead delivery amount can be varied by adjusting the step height H of the lead delivery mechanism, as described above. Therefore, according to the above embodiment, a mechanical pencil equipped with a lead delivery mechanism that delivers lead more reliably can be provided.

[0096] As shown in Figure 1, the mechanical pencil 1 has a clip 70a and a cover 70 that fits into the cylinder 6. The cover 70 has: a sleeve cover 71, a lead feeding member 72 serving as a lead feeding part, and a buffer spring 73. In this specification, the locking end side is defined as the "front" side and the opening end side is defined as the "rear" side in the axial direction of the cover 70. The lead feeding mechanism utilizing the lead feeding part of the cover 70 will be described with reference to Figures 20 and 21.

[0097] As shown in Figures 1 and 21(B), the cover 71 is a cover-shaped component that locks the front end. The cover 71 is installed on the front end of the cover 70 to form the locking end of the cover 70. The core delivery component 72 is configured to move back and forth inside the front end of the cover 70. A buffer spring 73 is disposed between the cover 71 and the core delivery component 72, and the buffer spring 73 pushes the core delivery component 72 backward.

[0098] Figure 20 is a longitudinal sectional view of the lead delivery member 72. The lead delivery member 72 is a cylindrical member. In Figure 20, the left side is positioned as the front side of the cover 70. An insertion hole 72a, a circular opening for inserting the front end of the mechanical pencil 1, i.e., the insert slider 9, is provided on the rear end face of the lead delivery member 72. The bottom surface of the insertion hole 72a has an inner diameter R narrower than the entrance of the insertion hole 72a, and a receiving recess 72b with a cylindrical inner circumferential surface of depth D2. A conical surface 72c is provided behind the receiving recess 72b. The inner diameter R of the receiving recess 72b is set to correspond to the outer diameter of the lead 7 used in the mechanical pencil 1. Specifically, the inner diameter R of the receiving recess 72b is set to be slightly larger than the outer diameter of the lead 7, and is configured to receive the front end of the lead 7.

[0099] Figure 21 is an enlarged cross-sectional view illustrating the feeding of the lead 7 in the mechanical pencil 1. Figure 21(A) shows the state of the mechanical pencil 1 before the lead 7 is fed out without the cover 70 being engaged with the cylinder 6. Figure 21(B) shows the state of the mechanical pencil 1 after the cover 70 is engaged with the cylinder 6. Figure 21(C) shows the state of the mechanical pencil 1 after the lead 7 is fed out with the cover 70 removed from the cylinder 6.

[0100] In Figure 21(A), the pen lead 7 does not protrude from the slider 9. That is, it indicates that after the user finishes a continuous writing action, the pen lead 7 is retracted to prevent it from protruding from the slider 9.

[0101] Next, as shown in Figure 21(B), the cover 70 is fitted onto the cylinder 6. At this time, the front end of the mechanical pencil 1, that is, the front end of the lead 7 and the slider 9, is inserted into the insertion hole 72a of the lead delivery member 72. As mentioned above, the inner diameter R of the receiving recess 72b is set to correspond to the outer diameter of the lead 7, so the receiving recess 72b receives the front end of the lead 7. On the other hand, the outer diameter of the front end of the slider 9 is set to be larger than the inner diameter R of the receiving recess 72b. Therefore, the front end of the slider 9, as it is inserted into the cover 70, is not received in the receiving recess 72b, but is stuck on the conical surface 72c. As a result, the slider 9 retracts relative to the lead 7 within the cylinder 6, and as a result, within the cover 70, the lead 7 protrudes from the front end of the slider 9 by only a length equal to the depth D2 of the receiving recess 72b.

[0102] Next, as shown in Figure 21(C), the cap 70 is removed from the cylinder 6 to begin the writing action. At this time, the retracted slide 9 and the retaining clip 10 disposed inside the slide 9 are advanced by the spring force of the cam abutting against the spring 18. As a result, the pen refill 7 held by the retaining clip 10 is pulled out from the ball bearing clip 11 and is fed out by a depth D2 relative to the receiving recess 72b at the front end of the slide 9. Therefore, the amount of pen refill 7 fed out, that is, the amount fed out, is equal to the depth D2 of the receiving recess 72b.

[0103] Generally, to prevent the lead from protruding from the tip or slider at the end of a continuous writing action, the lead must be ejected by pressing the button at least once before starting the next writing action. Even in mechanical pencils with such a lead ejection mechanism, the writing action is necessary for automatic lead ejection; therefore, at least one pressing action must be performed to eject the lead before starting the writing action.

[0104] According to the lead delivery member 72, the lead 7 can be delivered simply by attaching or detaching the cap 70 from the cylinder 6. That is, the lead can be delivered without pressing before writing begins. Therefore, a mechanical pencil can provide a completely new lead delivery operation that differs from the previous pressing operation.

[0105] Furthermore, assuming the pen refill 7 protrudes from the slider 9 longer than the depth D2 of the receiving recess 72b, the protrusion of the pen refill 7 will not change even when the cap 70 is fitted onto the cylinder 6. That is, in this state, the front end of the slider 9 will not be stuck on the conical surface 72c, and therefore, the slider 9 will not retract relative to the pen refill 7 within the cylinder 6. At this time, although the longer protruding front end of the pen refill 7 presses against the refill delivery member 72, the refill delivery member 72 advances against the spring force of the buffer spring 73 to absorb the pressure.

[0106] The cover 71 can also be removed to replace the refill delivery member 72. That is, the amount of refill protrusion 7 varies according to the user's preference. For example, some users find it convenient to write for extended periods because the refill 7 protrudes sufficiently, while others prefer a less protruding refill 7 so they don't have to worry about it breaking. Therefore, refill delivery members 72 with various depths D2 of receiving recesses 72b can be prepared in advance and replaced according to the user's preference. Alternatively, the buffer spring 73 can be omitted, and the refill delivery member 72 can be fixed inside the front end of the cover 70.

[0107] As the core delivery part of the core delivery member 72, it can be configured arbitrarily as long as the slider 9 can be pushed back relative to the pen refill 7 when the cover 70 is fitted into the cylinder 6. That is, when the cover 70 is fitted, as long as the front end of the pen refill 7 can be accommodated in the receiving recess 72b, and the front end of the slider 9 is not accommodated in the receiving recess 72b and is stuck and pushed back, the shape of the receiving recess 72b can be configured arbitrarily. For example, when the cover 70 is fitted, the slider 9 can be formed on the inner circumferential surface of the cover 70 so that it is pushed back relative to the pen refill 7, or it can be a plurality of protrusions extending inward.

[0108] In the above-described embodiment, the slide 9 is pushed forward by the cam abutting the spring 18 to activate the lead delivery mechanism. However, the lead delivery member 72 of the cap 70 is also applicable to mechanical pencils that do not push the slide forward. The mechanical pencil may or may not have a ball bearing. For example, the lead delivery member of the cap can also be used for a sliding tube type mechanical pencil where the tubular lead guide, which is mounted on the pencil tip member, moves forward along with the protruding action of the lead during the pressing operation, and the lead guide also moves backward along with the wear of the lead during writing.

[0109] Figure 22 is an enlarged perspective view of the cover 70. On the inner circumferential surface of the cover 70, specifically near the opening end, there are a plurality of locating recesses 70b arranged at equal intervals along the circumferential direction. Each locating recess 70b is a rearward-opening recess, forming a bell-shaped curve when viewed radially outward from the central axis. That is, a convex curved surface 70ba is formed on the inner surface of the front side of the locating recess 70b, and a concave curved surface 70bb is formed on the inner surface of the rear side of the locating recess 70b.

[0110] Figure 23 is an enlarged perspective view of the shaft cylinder 6. Further as shown in Figure 2, the outer circumferential surface of the shaft cylinder 6 has a plurality of locating protrusions 6a arranged at equal intervals along the circumferential direction. Specifically, it has three locating protrusions 6a. Each locating protrusion 6a extends forward. A portion of the outer surface of the locating protrusion 6a on its front side has a convex curved surface 6aa. A portion of the convex curved surface 6aa of the locating protrusion 6a is complementary to a portion of the convex curved surface 70ba of the locating recess 70b. That is, the locating protrusions 6a and the locating recess 70b have complementary portions.

[0111] As shown in Figures 1 and 21(B), a ring-shaped magnet 80 is disposed inside the cover 70. The magnet 80 is, for example, a neodymium magnet. Alternatively, a plurality of magnets may be disposed at equal intervals along the circumference instead of the ring-shaped magnet 80. On the other hand, the aforementioned grip portion 8 is a first magnetic body made of magnetic material. With the magnet 80 disposed inside the cover 70, when the cover 70 is fitted onto the shaft cylinder 6, an attractive force caused by magnetic force acts between the grip portions 8.

[0112] When fitting the cover 70 to the shaft cylinder 6, one hand typically holds the shaft cylinder 6 while the other hand holds the cover 70, and the open end of the cover 70 is inserted into the shaft cylinder 6. When the cover 70 is inserted to the predetermined depth, the magnetic force acting between the grip 8 and the magnet 80 pulls the cover 70 further in. At this point, aligning the positioning protrusion 6a of the shaft cylinder 6 and the positioning recess 70b of the cover 70 along the axial direction allows the positioning protrusion 6a and positioning recess 70b to fit together without interference, thus fitting the shaft cylinder 6 and the cover 70. On the other hand, if the positioning protrusion 6a of the shaft cylinder 6 and the positioning recess 70b of the cover 70 are not aligned along the axial direction, that is, if they are misaligned circumferentially.

[0113] When the positioning protrusion 6a of the shaft cylinder 6 and the positioning recess 70b of the cover 70 are only slightly offset in the circumferential direction, they are attracted by magnetic force, and the convex curved surface 6aa of the positioning protrusion 6a abuts against the concave curved surface 70bb of the positioning recess 70b. As a result, the positioning protrusion 6a and the positioning recess 70b cooperate, and the shaft cylinder 6 or the cover 70 rotates around the central axis in such a way that the positioning protrusion 6a and the positioning recess 70b are engaged, thus achieving the engagement of the shaft cylinder 6 and the cover 70.

[0114] When the positioning protrusion 6a of the shaft cylinder 6 and the positioning recess 70b of the cover 70 are significantly misaligned circumferentially, even under magnetic attraction, the convex surface 6aa of the positioning protrusion 6a and the concave surface 70bb of the positioning recess 70b will not abut. Therefore, the positioning protrusion 6a and the positioning recess 70b will not cooperate, and the shaft cylinder 6 and the cover 70 will not engage. To resolve this, hold the cover 70 with one hand and rotate it around the central axis until the convex surface 6aa of the positioning protrusion 6a and the concave surface 70bb of the positioning recess 70b abut. As a result, the positioning protrusion 6a and the positioning recess 70b cooperate, and by means of the engagement of the positioning protrusion 6a and the positioning recess 70b, the shaft cylinder 6 or the cover 70 rotates around the central axis, thus engaging the shaft cylinder 6 and the cover 70.

[0115] Generally, the engagement of the shaft sleeve and the cover is achieved by a protrusion formed on the inner circumferential surface of the cover passing over a protrusion formed on the outer circumferential surface of the shaft sleeve. According to the above embodiment, since the engagement of the shaft sleeve 6 and the cover 70 utilizes magnetic attraction, it is unnecessary to press the cover 70 forcefully against the shaft sleeve 6. As a result, when the cover 70 is inserted at an angle to the central axis of the shaft sleeve 6, there is no concern about damaging the outer circumferential surface of the shaft sleeve 6 with the edge of the open end of the cover 70. Furthermore, even children with limited strength or the elderly can easily engage the shaft sleeve 6 and the cover 70.

[0116] Furthermore, when identifying symbols, text, patterns, or shapes on the outside of both the shaft cylinder 6 and the cover 70, the rotational direction of the shaft cylinder 6 and the cover 70 around the central axis can be correctly positioned. In summary, according to the above embodiment, a writing instrument that allows the cover to fit correctly into the shaft cylinder can be provided. Moreover, since the magnetic force increases with relative distance, the shaft cylinder 6 and the cover 70 collide sharply when the fitting is complete. As a result, the user can feel a comfortable pressing sensation and hear a pressing sound, and can confirm that the fitting has indeed been completed.

[0117] Furthermore, as shown in Figures 1, 2, and 4, a second magnetic body 81 made of magnetic material can also be disposed at the rear end of the shaft cylinder 6, that is, at the rear end of the rear shaft 3. This allows the cap 70 to be fitted into the rear end of the shaft cylinder 6 for writing operations, utilizing the attraction force caused by magnetism. In this case, a positioning protrusion 6a cooperating with the positioning recess 70b of the cap 70 can also be provided at the rear end of the shaft cylinder 6. In the above embodiment, although the positioning protrusion 6a is formed on the outer peripheral surface of the shaft cylinder 6 and the positioning recess 70b is formed on the inner peripheral surface of the cap 70, it is also possible to form the positioning recess on the outer peripheral surface of the shaft cylinder 6 and the positioning protrusion on the inner peripheral surface of the cap 70. Furthermore, the mechanical pencil 1 may not have the second magnetic body 81.

[0118] In the above-described embodiment, although a magnet 80 is arranged on the cover 70 side and a first magnetic body (not a magnet) is arranged on the shaft cylinder 6 side, it is also possible to arrange the first magnetic body on the cover 70 side and the magnet on the shaft cylinder 6 side, for example, inside the grip portion 8. However, since the grip portion 8 is exposed to the outside when the cover 70 is removed, it is ideal to arrange the first magnetic body on the shaft cylinder 6 side, so that there will be no point of attraction to surrounding magnetic bodies, such as clips on the table. It is also possible to arrange magnets on both sides of the shaft cylinder 6 and the cover 70. It is also possible to provide the first magnetic body in a part of the shaft cylinder 6 other than the grip portion 8.

[0119] While each of the positioning protrusions 6a and positioning recesses 70b is formed in three in the above embodiment, it can also be one, two, or more than four. The positioning protrusions 6a and positioning recesses 70b cooperate with each other only when slightly offset in the circumferential direction, allowing the shaft cylinder 6 or the cover 70 to rotate around the central axis. As long as the shaft cylinder 6 and the cover 70 can be fitted together, they can be configured arbitrarily. For example, the positioning protrusion 6a shown in FIG. 23 can be made to be completely complementary to the positioning recesses 70b shown in FIG. 22.

[0120] The aforementioned method of engaging the cylinder and cap using magnetic attraction is applicable not only to mechanical pencils but also to other writing instruments, such as ballpoint pens, felt-tip pens, markers, fountain pens, and thermochromic writing instruments. Omitting the positioning protrusion 6a and positioning recess 70b allows for a writing instrument that uses only magnetic attraction to engage the cylinder and cap.

[0121] Figure 24 is a perspective view of the retaining chuck 10, and Figure 25 is a longitudinal sectional view of the retaining chuck 10. In Figure 25, the left side is positioned as the front side of the mechanical pencil 1. As described above, a through hole 10a extending along the axial direction is formed in the retaining chuck 10. The retaining chuck 10 has a cylindrical small-diameter portion 10b and a flange portion 10c provided on the outer peripheral surface of the rear end of the small-diameter portion 10b. A core-holding portion 10d, which is narrower than the other portions, is provided inside the front side of the through hole 10a. A conical surface 10e, which widens rearward, is provided inside the through hole 10a behind the core-holding portion 10d.

[0122] As shown in Figure 24, the lead holding portion 10d of the through hole 10a is an elongated hole. Specifically, the cross-sectional shape of the lead holding portion 10d of the through hole 10a is a rounded rectangle. Furthermore, since the lead holding portion 10d of the through hole 10a only needs to be an elongated hole, its cross-sectional shape can also be oval, or more specifically, oblong or elliptical. The dimensions of the elongated hole, such as the length and aspect ratio of a rounded rectangle, or the lengths of the major and minor axes of an ellipse, are determined through prior experiments based on the outer diameter of the lead 7 generally used in the mechanical pencil 1 or the composition of the lead 7.

[0123] Because the lead-holding portion 10d of the through hole 10a is an elongated hole, it is more prone to elastic deformation compared to a typical round hole lead-holding portion. That is, the elongated hole, along the direction of its elongated shape, is similar to a round hole in that it is less prone to elastic deformation, but it is more prone to elastic deformation in the direction orthogonal to the direction of its elongated shape. Therefore, even if the outer diameter of the lead 7 or the size of the through hole in the retaining clip 10 is slightly uneven during manufacturing, this can be absorbed by elastic deformation in the direction orthogonal to the direction of the elongated shape. Thus, a mechanical pencil can be provided that allows for a more appropriate setting of the sliding resistance between the lead 7 and the retaining clip 10.

[0124] In a typical mechanical pencil, the sliding contact between the lead and the retaining clip occurs only during lead ejection caused by a pressing operation. However, as described above, in the mechanical pencil 1 equipped with a rotary drive mechanism and a lead ejection mechanism, the sliding contact between the lead 7 and the retaining clip 10 occurs not only during lead ejection caused by a pressing operation but also during normal writing. Therefore, to ensure the rotary drive mechanism and lead ejection mechanism function properly, it is ideal to more precisely set the sliding resistance between the lead and the retaining clip. The mechanical pencil 1, by using an elongated lead retaining portion 10d through the through hole 10a, allows for a more precise setting of the sliding resistance between the lead 7 and the retaining clip 10.

[0125] The retainer 10 is made of elastic materials such as NBR, EPDM, fluororubber, or silicone rubber. Fluororubber retainers 10 are particularly desirable from the viewpoints of resistance to creep and chemical corrosion. That is, although the pen refill 7 contains some oil, the influence of the oil is further reduced by using fluororubber to manufacture the retainer 10. As a result, a wide variety of oil components and formulations can be selected for the pen refill 7, allowing for the manufacture of more diverse pen refills. In this case, the core retainer 10d can be either an elongated hole or a general circular cross-sectional shape.

[0126] In the above-described embodiment, although the retaining chuck 10 has a cylindrical small-diameter portion 10b, the retaining chuck as a whole is also formed in a conical shape. That is to say, as long as the core retaining portion 10d of the through hole 10a is an elongated hole, the shape of the retaining chuck 10 can be arbitrarily configured.

[0127] 1: Mechanical pencil 2: Front axle 3: Rear axle 4: Pen tip components 6: Shaft and cylinder 6a: Positioning convex part 7: Pen refill 8: Grip section (first magnetic element) 9: Sliding parts 10: Keep the clamp in place 10a: Through hole 10d: Core holding part 11: Ball chuck 12: Relay components 17: Coil Spring 18: Cam abutment spring 19: Chip Box 20: Pressing bar 21: Coil Spring 30: Rotary drive mechanism 40: Rotor 50: Turntable Cam Component 51: Turntable Cam 52: Rail Cam Component 53: Tracked Cam 54: Delivery Cam Surface 55: Step difference 56: Coil Spring 60: Clutch mechanism 61: Input clutch cam 62: Output clutch cam 63: Clutch cam surface 64: Transmission Cam 65: Delivery Cam 65c: Connecting part 66: Clutch Cam Retainer 70: Lid 70b: Positioning recess 71: Cover 72: Core delivery component 72a: Insertion Hole 72b: Receiving recess 73: Buffer spring 80:Magnet 81: Second magnetic body

Claims

1. A mechanical pencil, characterized by comprising: a ball bearing that allows the lead to advance and prevents it from retracting; a rotary drive mechanism having a rotor that is driven to rotate in one direction by a backward movement in the axial direction caused by writing pressure received by the lead held by the ball bearing and a forward movement in the axial direction caused by the release of writing pressure; a feed cam surface having an annular cam surface and a drop in the axial direction provided on the annular cam surface; an input member that rotates in response to the rotational driving force of the rotor; and an output member having: a contact member abutting against the feed cam surface and a slider having a retaining clip for holding the lead, wherein the contact member moves along the feed cam surface according to the rotation of the output member, and the lead held by the retaining clip is pulled out by the ball bearing by the forward movement of the slider when the contact member falls into the drop; It also has a clutch mechanism that transmits the rotational motion of the input component to the output component, such that when the input component rotates only by a first rotation angle, the output component rotates only by a second rotation angle smaller than the first rotation angle.

2. As in request item 1, the mechanical pencil, wherein, The aforementioned clutch mechanism is either a meshing clutch or a friction clutch.

3. As in request item 1, the mechanical pencil, wherein, The aforementioned clutch mechanism is a meshing clutch, with an input cam surface formed on the aforementioned input member and an output cam surface formed on the aforementioned output member that faces the aforementioned input cam surface. Only during a portion of the rotational motion of the aforementioned rotor, the aforementioned input cam surface and the aforementioned output cam surface engage, and the rotational motion of the aforementioned rotor is transmitted to the aforementioned output member via the aforementioned input member.

4. As in request item 3, the mechanical pencil, wherein, The aforementioned rotary drive mechanism includes a first cam forming member and a second cam forming member. The aforementioned rotor is formed into an annular shape, with a first cam surface and a second cam surface formed on one end face and the other end face respectively along its axial direction. A first fixed cam surface and a second fixed cam surface are formed on the aforementioned first cam forming member and the aforementioned second cam forming member, respectively, facing the aforementioned first cam surface and the aforementioned second cam surface. This causes the aforementioned ball chuck to retract under the aforementioned writing pressure, with the aforementioned first cam surface of the rotor abutting and engaging with the aforementioned first fixed cam surface. Upon release of the aforementioned writing pressure, the aforementioned second cam surface of the rotor abuts and engages with the aforementioned second fixed cam surface. When the first cam surface of the aforementioned rotor is engaged with the first fixed cam surface, the second cam surface of the aforementioned rotor and the second fixed cam surface are set to be phase-displaced relative to one tooth of the cam in the axial direction. When the second cam surface of the aforementioned rotor is engaged with the second fixed cam surface, the first cam surface of the aforementioned rotor and the first fixed cam surface are set to be phase-displaced relative to one tooth of the cam in the axial direction. The cam spacing in the aforementioned clutch mechanism is set to be smaller than the cam spacing in the aforementioned rotary drive mechanism.

5. Mechanical pencils as requested in any of items 1 to 4, wherein, The aforementioned ball chuck is configured to rotate by receiving the rotational driving force of the aforementioned rotor, thereby causing the pen refill to rotate.

6. Mechanical pencils as requested in any of items 1 to 4, wherein, A viscous fluid is disposed between the aforementioned output component and the shaft cylinder to restrict the movement of the aforementioned output component in the axial direction.

7. Mechanical pencils as requested in any of items 1 to 4, wherein, Adjusting the height of the aforementioned drop allows for adjustment of the amount of pen refill dispensed.

8. As in request item 7, the mechanical pencil, wherein, It further comprises: a first cam member in the shape of an annular or cylindrical shape, and a second cam member in the shape of an annular or cylindrical shape disposed radially outside the first cam member, wherein the first cam member and the second cam member cooperate to form the aforementioned delivery cam surface.

9. As in request item 8, the mechanical pencil, wherein, The height of the aforementioned drop is adjusted by rotating the first cam member and the second cam member relative to each other around the central axis.

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