Mechanical pencil

Abstract

An automatic pencil (1) is provided with a ball holder (11), a rotation drive mechanism (30) having a rotation body (40), an ejection cam surface (54) having a step (55) in an axial direction, an input member that rotates in response to a rotation drive force of the rotation body, and an output member having an abutting member (65c) that abuts against the ejection cam surface and a sliding member (9) provided with a holding holder (10) that holds a lead (7), the automatic pencil being configured so that the abutting member moves along the ejection cam surface in response to rotation of the output member, and the lead held by the holding holder is pulled out from the ball holder by a forward movement of the sliding member when the abutting member falls into the step, and the automatic pencil is further provided with a clutch mechanism that transmits a rotation movement of the input member to the output member in such a manner that the output member rotates a second rotation angle smaller than a first rotation angle when the input member rotates the first rotation angle.

Description

Technical Field

[0001] This invention relates to a mechanical pencil. Background Technology

[0002] In mechanical pencils, for example, a press operation is performed on a presser located at the rear end of the pencil barrel, thereby using a tip component or slider mounted on the front end of the pencil barrel to advance a certain amount of lead. Since the lead wears down with each writing action, a press operation is required after each certain amount of writing action.

[0003] A known mechanical pencil (see Patent Document 1) automatically feeds out the lead sequentially using the writing pressure accompanying the writing action. The mechanical pencil described in Patent Document 1 includes: a ball chuck that holds the lead; a rotation drive mechanism that drives a rotating body to rotate in one direction by receiving a backward movement in the axial direction generated by the writing pressure exerted on the lead held by the ball chuck and a forward movement in the axial direction generated by the release of the writing pressure; and a lead feeding mechanism that includes a cam member and a retaining chuck, and feeds the lead forward by receiving the rotational driving force of the rotating body of the rotation drive mechanism. The ball chuck is configured to allow the lead to move forward and prevent it from moving backward.

[0004] As described later, the ball clamp has a cylindrical fastener, a clamp body disposed within the fastener and holding the pen refill, and multiple balls. A conical surface extending forward is formed on the inner circumferential surface of the fastener. When writing pressure is applied to the pen refill, the clamp body and the balls retract together, and the balls abut against the conical surface within the cylindrical fastener. The further the balls retract, the more they move towards the center along the conical surface. Using the balls that have moved to the center, the clamp body also moves towards the center, resulting in the pen refill being secured and held by the clamp body. Thus, the refill's retraction is prevented. On the other hand, when a force is applied to pull the pen refill forward, the balls and the clamp body move forward together, resulting in the release of the fastening mechanism using the conical surface and the balls; that is, the clamp body is no longer affected by the fastener, and therefore, the pen refill can be pulled forward without resistance. Furthermore, the clamp body is subjected to a rearward force by a coil spring.

[0005] The pen refill delivery mechanism includes: a cam member having a cam surface that rises circumferentially and a step in the axial direction; and a slider having an abutment. The slider is spring-driven forward, thereby abutting the abutment 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 upward along the cam surface of the cam member, while the slider gradually retracts in the axial direction.

[0006] Then, when the abutment of the slider reaches the step of the cam member, the abutment falls down the step under the action of the spring that applies force to the slider. At that instant, the slider also undergoes a forward movement equivalent to the height difference of the step. At the same time, the retaining chuck disposed within the slider also moves forward, thus pulling the pen refill, which is held in sliding contact with the retaining chuck, out of the ball chuck, thereby dispensing the pen refill. That is, when the rotating body rotates one revolution, the abutment travels one revolution along the cam surface to dispense the pen refill.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2016-153246 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] Preferably, a lead delivery mechanism is used to deliver a lead of the same length as the lead length reduced due to wear (amount of wear). This allows the user to write continuously without pressing the button. The lead delivery amount depends on the height of the step on the cam surface. However, in the ball joint design, the lead advance distance caused by the step on the cam surface does not directly determine the lead delivery amount.

[0012] In other words, after the pen refill is pulled out of the ball joint using a press-button operation or the refill delivery mechanism, but before writing pressure is applied to the pen refill, there is still room for further retraction of the ball joint body, the ball, and the pen refill (hereinafter referred to as "recoil"). Specifically, the recoil is about 0.2mm. For example, when the number of writing strokes (strokes) required to rotate the pen one revolution is set to 40, the wear on the pen refill depends on the writing pressure and the frictional resistance between the pen refill and the writing surface, but is approximately 0.05mm. When the step height of the cam surface is set to 0.25mm to account for recoil, the wear generated by the writing action is the same as the delivery amount generated by the pen refill delivery mechanism, allowing the user to write continuously without pressing the button.

[0013] However, the recoil 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, the refill may still retract by more than 0.25mm when considering the recoil error. That is, the error in the refill delivery amount is 0.05mm ± 0.1mm, meaning there is a possibility that the refill may not actually be delivered. On the other hand, if the step height of the cam surface is larger to account for recoil, for example, set to 0.5mm, the refill may overextend.

[0014] Therefore, if the frequency of refill delivery can be reduced by delaying the timing of refill delivery using the refill delivery mechanism, and longer refill delivery can be performed after the refill wears further, it can prevent the refill from actually not being delivered due to errors.

[0015] The purpose of this invention is to provide a mechanical pencil with a lead delivery mechanism that can deliver the lead more reliably.

[0016] Solution for solving the problem

[0017] One technical solution of the present invention provides a mechanical pencil, characterized in that the mechanical pencil comprises: a ball clamp that allows the lead to advance and prevents the lead from retracting; a rotation drive mechanism having a rotating body that receives a backward movement in the axial direction caused by writing pressure exerted by the lead held by the ball clamp and a forward movement in the axial direction caused by the release of writing pressure, thereby driving the rotating body to rotate in one direction; 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 receives the rotational driving force of the rotating body and rotates; and an output member having The mechanical pencil has an abutment member that abuts against the feed cam surface and a sliding member with a retaining clip for holding the lead. The abutment member moves along the feed cam surface according to the rotation of the output member. The lead held by the retaining clip is pulled out of the ball clamp by the forward movement of the sliding member when the abutment member falls into the drop. The mechanical pencil also has a clutch mechanism that transmits the rotational motion of the input member to the output member in such a way that when the input member rotates by a first rotation angle, the output member rotates by a second rotation angle smaller than the first rotation angle.

[0018] Alternatively, the clutch mechanism can be an engaging clutch or a friction clutch. Alternatively, the clutch mechanism can be an engaging clutch, with an input cam surface formed on the input member and an output cam surface opposite to the input cam surface formed on the output member. The input cam surface and the output cam surface engage only when a portion of the rotating body rotates, and the rotational motion of the rotating body is transmitted to the output member via the input member. Alternatively, the rotary drive mechanism has a first cam forming member and a second cam forming member. The rotating body is formed in 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. The rotary drive mechanism is configured with a first fixed cam surface formed on the first cam forming member opposite to the first cam surface and a second fixed cam surface formed on the second cam forming member opposite to the second cam surface. The rotary drive mechanism is configured such that, by utilizing the retracting action of the ball chuck generated by the writing pressure, the first cam surface of the rotating body abuts and engages with the first fixed cam surface, and the rotational motion is transmitted to the output member via the input member. In addition to the writing pressure, the second cam surface of the rotating body abuts and engages with the second fixed cam surface. When the first cam surface of the rotating body is engaged with the first fixed cam surface, the second cam surface and the second fixed cam surface of the rotating body are set to be phase-shifted relative to one tooth of the cam in the axial direction. When the second cam surface of the rotating body is engaged with the second fixed cam surface, the first cam surface and the first fixed cam surface of the rotating body are set to be phase-shifted relative to one tooth of the cam in the axial direction. The pitch of the cam in the clutch mechanism is set to be smaller than the pitch of the cam in the rotary drive mechanism. Alternatively, the ball joint can be configured to rotate by receiving the rotational driving force of the rotating body, thereby rotating the lead. Alternatively, a viscous fluid that inhibits the axial movement of the output member can be disposed between the output member and the pen barrel. Alternatively, the mechanical pencil can be configured to adjust the lead delivery amount by adjusting the height of the drop. Alternatively, the mechanical pencil may also include a first annular or cylindrical cam member and a second annular or cylindrical cam member disposed radially outside the first cam member, the first cam member and the second cam member cooperating to form the feed cam surface. Alternatively, the height of the drop may be adjusted by rotating the first cam member and the second cam member relative to each other about a central axis.

[0019] The effects of the invention

[0020] According to embodiments of the present invention, a common effect is achieved in providing a mechanical pencil with a lead delivery mechanism that can deliver the lead more reliably. Attached Figure Description

[0021] Figure 1 This is a longitudinal sectional view of a mechanical pencil according to an embodiment of the present invention.

[0022] Figure 2 It is a 3D diagram of a mechanical pencil.

[0023] Figure 3 It is an enlarged cross-sectional view of the front half of a mechanical pencil.

[0024] Figure 4 This is an enlarged cross-sectional view of the rear half of a mechanical pencil.

[0025] Figure 5 It is a three-dimensional diagram illustrating the internal structure of a mechanical pencil.

[0026] Figure 6 This is an exploded 3D view of the clutch mechanism.

[0027] Figure 7 This is an enlarged sectional view of the rotary drive mechanism.

[0028] Figure 8 This is a schematic diagram illustrating the rotational drive of a rotating body in a rotary drive mechanism.

[0029] Figure 9 It continues Figure 8 A schematic diagram illustrating the rotational drive of a rotating body.

[0030] Figure 10 This is a three-dimensional view of the dial cam component.

[0031] Figure 11 This is a 3D view of the guide rail cam component.

[0032] Figure 12 This is another perspective view of the guide rail cam component.

[0033] Figure 13 It is a three-dimensional view of the combined dial cam assembly and guide rail cam assembly.

[0034] Figure 14 This is another perspective view of the combined dial cam assembly and guide rail cam assembly.

[0035] Figure 15 This is a schematic diagram showing the delivery cam surface.

[0036] Figure 16 This is a 3D view of the input clutch cam.

[0037] Figure 17 This is a 3D view of the output clutch cam.

[0038] Figure 18This is an enlarged 3D view illustrating the input clutch cam and the output clutch cam.

[0039] Figure 19 This is a schematic diagram illustrating the operation of a clutch mechanism that works in conjunction with a rotary drive mechanism.

[0040] Figure 20 This is a longitudinal sectional view of the pen refill ejector component.

[0041] Figure 21 This is an enlarged cross-sectional view of a mechanical pencil that shows the lead being fed out.

[0042] Figure 22 It is a magnified 3D view of the pen cap.

[0043] Figure 23 It is a magnified 3D view of the pen barrel.

[0044] Figure 24 It is a 3D diagram of the clamp.

[0045] Figure 25 This is a longitudinal sectional view of the clamp. Detailed Implementation

[0046] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In all the drawings, corresponding structural elements are labeled with common reference numerals.

[0047] Figure 1 This is a longitudinal sectional view of the mechanical pencil 1 according to an embodiment of the present invention. Figure 2 This is a 3D model of mechanical pencil 1. Figure 3 This is an enlarged sectional view of the front half of the mechanical pencil 1. Figure 4 This is an enlarged cross-sectional view of the rear half of the mechanical pencil 1. Figure 5 This is a three-dimensional diagram illustrating the internal structure of mechanical pencil 1. Figure 6 This is an exploded perspective view of the clutch mechanism 60.

[0048] The mechanical pencil 1 has a front barrel 2, a rear barrel 3 that is threadedly engaged with the outer peripheral surface of the rear end of the front barrel 2, and a tip member 4 that is threadedly engaged with the outer peripheral surface of the front end of the front barrel 2. The front barrel 2 and the rear barrel 3 constitute the barrel 6. Alternatively, the tip member 4 may also be included, referred to herein as the barrel 6. As described later, the mechanical pencil 1 is configured such that the tip 7 protrudes from the top end of the sliding member 9. In this specification, in the axial direction of the mechanical pencil 1, the side facing the tip 7 is designated as the "front" side, and the side opposite to the tip 7 side is designated as the "rear" side.

[0049] Reference Figure 3Inside the front end of the pen barrel 6, a slider 9 is configured to slide along the axial direction and rotate about the axial direction. The slider 9 is formed as a cylindrical shape with its outer diameter tapering in a stepped manner 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 top end of the slider 9. A retaining clip 10 with a through hole 10a formed in the center is disposed inside the slider 9. The through hole 10a of the retaining clip 10 slides in contact with the outer peripheral surface of the pen refill 7 to temporarily hold the pen refill 7.

[0050] A dial cam member 50, which is cylindrical and serves as the first cam member, and a guide cam member 52, which is annular and serves as the second cam member, are arranged along the axial direction on the outer peripheral surface of the slider 9. A generally cylindrical holding portion 8 is provided at the front end of the pen tip member 4 and on the outer peripheral surface of the dial cam member 50. The top end of the slider 9 protrudes from the hole at the front end of the dial cam member 50. The ball clip 11 that holds the pen refill 7, specifically the fastener 13, is fitted into the inner peripheral surface of the rear end portion of the slider 9.

[0051] The ball chuck 11 has a cylindrical fastener 13, a chuck body 14 disposed within the fastener 13, a cylindrical chuck retaining portion 15, and a plurality of balls 16. A tapered surface that widens towards the front is formed on the inner circumferential surface of the fastener 13. The chuck body 14 has a through hole for a pen refill 7 along its central axis, and the front end of the chuck body 14 is divided into multiple portions 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 fastener 13 in the axial direction. The plurality of balls 16 are disposed between the inner circumferential surface of the fastener 13 and the outer circumferential surface of the chuck body 14.

[0052] When writing pressure is applied to the pen refill 7, the clip body 14, together with the ball 16, abuts against the conical surface inside the cylindrical fastener 13, thus holding the pen refill 7 in place. This prevents the pen refill 7 from retracting. On the other hand, when a force is applied to pull the pen refill 7 forward, since the clip body 14 is not subjected to the fastener 13, the pen refill 7 can be pulled forward without resistance. In other words, the ball clip 11 functions in a way that allows the pen refill 7 to move forward while preventing it from retracting.

[0053] A coil spring 17 is arranged to surround the main body 14 of the chuck. The rear end of the coil spring 17 is fitted into the outer surface of the main body 14 of the chuck, and the front end of the coil spring 17 is supported by a step formed on the inner circumferential surface of the fastener 13. The coil spring 17 exerts a rearward force on the main body 14 of the chuck, as a result, the ball chuck 11 can maintain the state of holding the pen refill 7. A cam abutment spring 18, which is a coil spring, is arranged to surround the fastener 13. The cam abutment spring 18 exerts a forward force on the slider 9. The front end of the pen refill shell 19 is fitted into the outer circumferential surface of the rear end of the chuck holding part 15. The pen refill shell 19 is formed into a cylindrical shape and houses the pen refill 7 inside.

[0054] The ball collet 11 is connected to the input clutch cam 61 of the clutch mechanism 60, which will be described later. Specifically, the input clutch cam 61 is cylindrical, and the outer peripheral surface of the rear end of the fastener 13 of the ball collet 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. (Refer to...) Figure 5 and Figure 6 As described later, the clutch mechanism 60 has a forward-protruding abutment 65c. The abutment 65c is forced forward by the cam abutment spring 18 via the slider 9. Therefore, the slider 9, ball collet 11, relay member 12, input clutch cam 61, and abutment 65c can move integrally within the pen barrel 6 along the axial direction. The rear end of the relay member 12 is connected to the rotary drive mechanism 30, which will be described later.

[0055] Reference Figure 4 A press bar 20, serving as a press member, is provided at the rear end of the pen barrel 6 in a manner that allows it to move back and forth relative to the pen barrel 6. The press bar 20 is forced rearward by a coil spring 21. A partition wall portion 20a with a supplementary hole for the pen refill 7 is formed near the rear end of the press bar 20. An eraser 22 is detachably mounted inside the rear end of the press bar 20. A press cover 23 is detachably mounted on the outer peripheral surface of the rear end of the press bar 20, which protects the eraser 22 from contamination. The press bar 20 fits into the outer peripheral surface of the rear end of the pen refill housing 19.

[0056] By pressing the lever 20 or the cap 23 forward, the pen refill shell 19 is advanced. This, in turn, pushes the chuck body 14 forward using the chuck holding part 15. Simultaneously, the pen refill 7, held by the chuck body 14, also advances, thus feeding the pen refill 7 out of the sliding member 9.

[0057] When the press operation is released, the press bar 20 retracts and returns to its original position using the force of the coil spring 21. At this time, the chuck body 14 retracts using the force of the coil spring 17. On the other hand, since the pen refill 7 is held by the retaining chuck 10 disposed within the slider 9, the pen refill 7 is pulled out from the chuck body 14 without resistance under the action of the ball chuck 11. As a result, the pen refill 7 is delivered from the slider 9, so that the pen refill 7 can be delivered in a predetermined amount each time the press operation is repeated. While maintaining the state in which the press bar 20 has been advanced by the press operation, the chuck body 14 protrudes from the fastener 13 and becomes released from holding the pen refill 7. In this state, the pen refill 7, which has been delivered from the slider 9, can be pushed back using a fingertip or the like.

[0058] Figure 7 This is an enlarged cross-sectional view of the rotary drive mechanism 30. The rotary drive mechanism 30 is disposed within the internal space of the rear pen barrel 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 pen barrel 2 and the front end face of the rotary drive mechanism 30, applying a rearward force to the rotary drive mechanism 30. The rearward movement of the rotary drive mechanism 30 under the force of the shaft spring 31 is restricted by the rear end face of the rotary drive mechanism 30 abutting against a stepped portion provided on the inner surface of the pen barrel 6. The pen refill shell 19 penetrates the interior of the relay member 12 and the interior of the rotary drive mechanism 30, and the pen refill shell 19 is separate from the rotary drive mechanism 30.

[0059] The rotary drive mechanism 30 includes a cylindrical rotating body 40, a cylindrical upper cam forming member 41 serving as a first cam forming member, a cylindrical lower cam forming member 42 serving as a second cam forming member, a cylindrical cylinder member 43, a cylindrical torque eliminator 44, and a helical buffer spring 45. These components of the rotary drive mechanism 30 are integrated and modularized.

[0060] 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 rotating body 40. Near the front end of the rotating body 40, there is a flange-shaped portion with a slightly larger diameter. A first cam surface 40a is formed on the rear end surface of this portion, and a second cam surface 40b is formed on the front end surface of this portion.

[0061] The upper cam forming member 41 surrounds the rotating body 40 behind the first cam surface 40a in a manner that allows the rotating body 40 to rotatably. The lower cam forming member 42 is fitted into the outer 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 surface of the upper cam forming member 41 opposite to the first cam surface 40a of the rotating body 40. A second fixed cam surface 42a, serving as a second fixed cam surface, is formed on the inner surface of the front end of the lower cam forming member 42 opposite to the second cam surface 40b of the rotating body 40.

[0062] A cylindrical cylinder member 43 is fitted onto the outer peripheral surface of the rear end of the upper cam forming member 41. A through hole 43a is formed at the rear end of the cylinder member 43, through which the pen refill shell 19 can pass. A cylindrical torque eliminator 44, movable along the axial direction, is disposed inside the cylinder member 43. A buffer spring 45 is disposed between the inner surface of the front end of the torque eliminator 44 and the inner surface of the rear end of the cylinder member 43. The buffer spring 45 applies a force to the rotating body 40 forward by means of the torque eliminator 44.

[0063] Here, the relay member 12 transmits the backward and forward movements (buffering movements) of the pen refill 7 based on the writing action to the rotary drive mechanism 30, i.e., the rotating body 40, and the relay member 12 transmits the rotational motion of the rotating body 40 of the rotary drive mechanism 30 generated by the buffering movement to the ball clamp 11 in the state of holding the pen refill 7. As a result, the pen refill 7 held by the ball clamp 11 also rotates.

[0064] When writing with the mechanical pencil 1, i.e., when no writing pressure is applied to the lead 7, the rotating body 40 is positioned forward under the force of the buffer spring 45, aided by the torque canceller 44. Therefore, the second cam surface 40b of the rotating body 40 abuts against the second fixed cam surface 42a and is engaged. When writing with the mechanical pencil 1, i.e., when writing pressure is applied to the lead 7, the ball joint 11 retracts against the force of the buffer spring 45, and the rotating body 40 also retracts. Therefore, the first cam surface 40a of the rotating body 40 abuts against the first fixed cam surface 41a and is engaged.

[0065] Figure 8 It is explained in order. Figure 1 A schematic diagram of the rotation drive function of the rotating body 40 of the mechanical pencil 1. Figure 9 It continues Figure 8 A schematic diagram illustrating the rotational driving effect of the rotating body 40. Figure 8 and Figure 9In the rotating body 40, a first cam surface 40a is formed in a circular shape on the upper side surface, i.e. the rear end surface, and a second cam surface 40b is formed in a circular shape on the lower side surface, i.e. the front end surface, and a second cam surface 40b is formed in a circular shape ...

[0066] 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 opposite to the first cam surface 40a of the rotating body 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 opposite to the second cam surface 40b of the rotating body 40. The first cam surface 40a and the second cam surface 40b formed on the rotating body 40, and the first fixed cam surface 41a formed on the upper cam forming member 41 and the second fixed cam surface 42a formed on the lower cam forming member 42, are formed with approximately the same pitch.

[0067] Figure 8 (A) shows the relationship between the rotating body 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 rotating body 40 engages with the second fixed cam surface 42a of the lower cam forming member 42 under the force of the buffer spring 45. At this time, the first cam surface 40a of the rotating body 40 and the first fixed cam surface 41a of the upper cam forming member 41 are set to be offset by half a phase (half a pitch) relative to one tooth of the cam in the axial direction.

[0068] Figure 8 (B) shows the initial state in which writing pressure is applied to the lead 7 when writing with the mechanical pencil 1. In this state, the rotating body 40 retracts and causes the buffer spring 45 to contract and retract along with the retraction of the ball clamp 11. As a result, the rotating body 40 moves toward the first fixed cam surface 41a of the upward cam forming member 41.

[0069] then, Figure 8 (C) shows a state where further writing pressure is applied to the pen refill 7 and the rotating body 40 retracts in such a way that it abuts against the first fixed cam surface 41a of the upper cam forming member 41. In this state, the first cam surface 40a of the rotating body 40 engages with the first fixed cam surface 41a of the upper cam forming member 41. Thus, the rotating body 40 receives a rotational drive corresponding to half a phase (half a pitch) of one tooth of the first cam surface 40a.

[0070] In addition, Figure 8 and Figure 9 The triangular mark at the center of the rotating body 40 is used to indicate the amount of rotational movement of the rotating body 40. Therefore, in Figure 8 In the state shown in (C), the second cam surface 40b of the rotating body 40 and the second fixed cam surface 42a of the lower cam forming member 42 are set to be offset by half a phase (half a pitch) relative to one tooth of the cam in the axial direction.

[0071] then, Figure 9 (D) shows the initial state after writing with the mechanical pencil 1 has ended and the writing pressure on the lead 7 has been released. In this state, the rotating body 40 moves forward under the force of the buffer spring 45. As a result, the rotating body 40 moves towards the downward cam forming member 42.

[0072] then, Figure 9 (E) shows the state in which the rotating body 40 advances under the force of the buffer spring 45, abutting against the second fixed cam surface 42a of the lower cam forming member 42. In this case, the second cam surface 40b of the rotating body 40 meshes with the second fixed cam surface 42a of the lower cam forming member 42. Thus, the rotating body 40 again receives a rotational drive corresponding to half a phase (half a pitch) of one tooth of the second cam surface 40b.

[0073] Therefore, as shown by the triangular mark depicted in the center of the rotating body 40, with the reciprocating motion (i.e., back-and-forth movement) of the rotating body 40 in the axial direction under writing pressure, the rotating body 40 receives a rotational drive corresponding to one tooth (one pitch) of the first cam surface 40a and the second cam surface 40b. The pen refill 7, held by the ball chuck 11, is also similarly driven to rotate. Thus, by utilizing one back-and-forth movement of the rotating body 40 in the axial direction caused by writing, the rotating body 40 receives a rotational motion corresponding to one tooth of the cam. By repeating the above actions, the pen refill 7 is driven to rotate sequentially. This prevents uneven wear of the pen refill 7 during writing and prevents significant variations in the thickness and density of the writing line.

[0074] In summary, the rotary drive mechanism has a first cam forming member and a second cam forming member. The rotating body is formed in an annular shape and has a first cam surface and a second cam surface formed on one end face and the other end face respectively in the axial direction. Furthermore, a first fixed cam surface is formed on the first cam forming member opposite to the first cam surface, and a second fixed cam surface is formed on the second cam forming member opposite to the second cam surface. The rotary drive mechanism is configured such that, utilizing the retracting action of the ball chuck generated by the writing pressure, the first cam surface of the rotating body... The first fixed cam surface abuts and engages with the first fixed cam surface. By releasing the writing pressure, the second cam surface of the rotating body abuts and engages with the second fixed cam surface. When the first cam surface of the rotating body is engaged with the first fixed cam surface, the second cam surface of the rotating body 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 rotating body is engaged with the second fixed cam surface, the first cam surface of the rotating body and the first fixed cam surface are set to be phase-displaced relative to one tooth of the cam in the axial direction.

[0075] Furthermore, the torque eliminator 44, which pushes the rotating body 40 forward under the force of the buffer spring 45, slides between its front end face and the rear end face of the rotating body 40, thereby preventing the rotational motion of the rotating body 40 from being transmitted to the buffer spring 45. That is, by using the torque eliminator 44, the rotational motion of the rotating body 40 is prevented from being transmitted to the buffer spring 45, thereby preventing the generation of torsional restoring torque that hinders the rotational movement of the rotating body 40 by the buffer spring 45.

[0076] As described above, the mechanical pencil 1 has a ball clip 11 and a rotating body 40. The mechanical pencil 1 is configured to release and hold the lead 7 by moving the ball clip 11 back and forth, thereby sending the lead 7 forward. The ball clip 11 is configured to be held in the pencil barrel 6 in such a way that it can rotate around the central axis while holding the lead 7. Furthermore, the rotating body 40 rotates by moving back and forth with the ball clip 11 under the writing pressure of the lead 7, and the rotational motion of the rotating body 40 is transmitted to the lead 7 via the ball clip 11.

[0077] Reference Figures 10 to 14 This section describes the pen refill delivery mechanism and the delivery amount adjustment mechanism. The pen refill delivery mechanism functions by receiving the rotational driving force of the rotating body 40 of the rotational drive mechanism 30 to deliver the pen refill 7 from the sliding member 9.

[0078] Figure 10 This is a perspective view of the dial cam component 50. Figure 10In this design, the dial cam member 50 is positioned such that its upper part forms the rear side of the mechanical pencil 1. The dial cam member 50 is a cylindrical member comprising: 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 dial cam 51 formed on the rear end face of the cam body 50a. The dial cam 51 comprises: 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.

[0079] Figure 11 This is a three-dimensional view of the guide rail cam component 52. Figure 12 This is another perspective view of the guide rail cam component 52. Figure 11 and Figure 12 In the mechanical pencil 1, the guide cam member 52 is positioned such that its upper part forms the rear side. The guide cam member 52 is formed in a ring shape. An adjustment recess 52a is formed on the front end face of the guide cam member 52. A plurality of fitting recesses 52b are formed on the bottom surface of the adjustment recess 52a at equal intervals along the circumference.

[0080] A guide cam 53 is formed on the rear end face of the guide cam member 52. The guide cam 53 has: a flat first annular cam surface 53a, which is located further forward and orthogonal to the central axis; a flat second annular cam surface 53b, which is located further rearward and orthogonal to the central axis; and an inclined surface 53c, which is a ramp-shaped annular cam surface, configured to rise circumferentially in a manner connecting one end of the first annular cam surface 53a and one end of 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.

[0081] Figure 13 This is a perspective view of the combined dial cam component 50 and guide rail cam component 52. Figure 14 This is another perspective view of the combined dial cam assembly 50 and guide rail cam assembly 52. Figure 13 as well as Figure 14In this arrangement, the dial cam member 50 and the guide cam member 52 are positioned such that their upper surfaces form the rear side of the mechanical pencil 1. The annular guide cam member 52 is inserted into the rear end of the cam body 50a of the dial cam member 50 and engaged by the flange portion 50b, thereby forming a combination. That is, the front end face of the guide cam member 52 abuts against the rear end face of the flange portion 50b of the dial cam member 50. At this time, the engaging protrusion 50c provided on the flange portion 50b of the dial cam member 50 engages with one of the engaging recesses 52b in the adjustment recesses 52a of the guide cam member 52. The guide cam member 52 is positioned radially outward from the dial cam member 50.

[0082] With the dial cam member 50 and the guide cam member 52 combined, the dial cam 51 of the dial cam member 50 is positioned near the guide cam 53 of the guide cam member 52. Thus, the dial cam 51 and the guide cam 53 cooperate to form a series, i.e., annular, feed cam surfaces 54 in the circumferential direction.

[0083] like Figure 3 As shown, the dial cam member 50 and the guide rail cam member 52 are arranged in combination on the outside of the slider 9. A portion of the outer peripheral surface of the dial cam member 50 and the outer peripheral surface of the guide rail cam member 52 are covered by the pen tip member 4 and the grip portion 8. The grip portion 8 engages with the outer peripheral surface of the dial cam member 50. Therefore, the grip portion 8 can rotate together with the dial cam member 50 around the central axis. A coil spring 56 is arranged between the inner surface of the front end of the pen tip member 4 and the flange portion 50b of the dial cam member 50. Furthermore, the slider 9 is maintained in contact with the delivery cam surface 54 by the abutment body 65c, which is forced forward by the cam abutment spring 18. The outer peripheral surface of the guide rail cam member 52 engages with the inner peripheral surface of the pen tip member 4, restricting the rotation of the guide rail cam member 52 relative to the pen tip member 4 and the pen barrel 6.

[0084] The shape of the feed cam surface 54 can be changed by rotating the dial cam member 50 and the guide rail cam member 52 relative to each other about a central axis. Specifically, the user rotates the dial cam member 50 about a central axis by holding the pen barrel 6 with one hand and rotating the grip part 8 with the other hand. Since the guide rail cam member 52 engages with the pen barrel 6, the dial cam member 50 rotates about a central axis relative to the guide rail cam member 52. The rotation of the dial cam member 50 relative to the guide rail cam member 52 is performed stepwise by the movement and engagement of the engagement protrusion 50c of the dial cam member 50 between corresponding adjacent engagement recesses 52b of the guide rail cam member 52. Therefore, the rotation of the dial cam member 50 relative to the guide rail cam member 52 about a central axis is performed stepwise within the range of the adjustment recesses 52a of the guide rail cam member 52 that allow the engagement protrusion 50c of the dial cam member 50 to move. Based on the position of the engagement protrusion 50c of the dial cam member 50 engaging with the engagement recess 52b of the guide rail cam member 52, the relative position between the dial cam member 50's dial cam 51 and the guide rail cam member 52's guide rail cam changes, resulting in a change in the shape of the delivery cam surface 54. The dial cam member 50 is forced by the helical spring 56 towards the guide rail cam member 52, and a locking sensation is achieved as the dial cam member 50 rotates relative to the guide rail cam member 52 in stages.

[0085] Next, refer to Figure 15 This describes the delivery of the pen refill 7 by the delivery cam surface 54. Figure 15 This is a schematic diagram showing the delivery cam surface 54. Figure 15 This is a diagram showing the positional relationship between the dial cam component 50 and the guide rail cam component 52, and is a circumferentially unfolded view of a cylindrical surface, including the delivery cam surface 54, around the central axis. Figure 15 In the middle, the top is the back of mechanical pencil 1.

[0086] Reference Figure 15 The dial cam member 50 is aligned with the guide rail cam member 52 by the radial overlap of the longitudinal wall 51c of the dial cam 51 and the inclined surface 53c of the guide rail cam 53. Figure 15 In the dial cam 51 and guide cam 53, the line (surface) located further back, i.e., higher up in the figure, constitutes the feed cam surface 54. That is, the second annular cam surface 51b of the dial cam 51 and the second annular cam surface 53b and inclined surface 53c of the guide cam 53 cooperate to form the feed cam surface 54. Furthermore, in the feed cam surface 54, the height (difference in elevation) of the step 55 (drop) in the axial direction formed by the second annular cam surface 51b of the dial cam 51 and the inclined surface 53c of the guide cam 53 is set as the step height H.

[0087] When the dial cam member 50 and the guide cam member 52 rotate relative to each other about the central axis with the longitudinal wall 51c of the dial cam 51 positioned on the side of the first annular cam surface 53a of the guide cam 53, the step height H becomes higher. On the other hand, when the dial cam member 50 and the guide cam member 52 rotate relative to each other about the central axis with the longitudinal wall 51c of the dial cam 51 positioned on the side opposite to the first annular cam surface 53a of the guide cam 53, the step height H becomes lower.

[0088] As described later, the rotating body 40 of the rotary drive mechanism 30 gradually drives the abutment body 65c to rotate based on the buffering action of the pen refill 7. That is, when viewed with the top end of the slider 9 in front, the abutment body 65c rotates to the right about the central axis. Utilizing this rotational motion, the abutment body 65c, which is forced forward by the cam abutment spring 18, moves circumferentially while cooperating with the delivery cam surface 54. That is, the abutment body 65c... Figure 15 The cam moves from right to left, thus gradually rising along the inclined surface 53c of the cam surface 54 that forms the guide cam 53.

[0089] When the abutment 65c reaches the step 55, it is pressed down by the force of the cam abutment spring 18 and falls into the step 55. That is, the abutment 65c moves forward from the second annular cam surface 51b of the dial cam 51 by an amount corresponding to the step height H of the step 55. At this time, along with the forward movement of the abutment 65c, the slider 9 and the retaining chuck 10 disposed inside the slider 9 also move forward. As a result, the pen refill 7 held in the retaining chuck 10 is pulled out from the ball chuck 11 and is correspondingly fed out from the top end of the slider 9 by an amount corresponding to the step height H. Therefore, the amount of pen refill 7 fed out, that is, the amount fed out, is equal to the step height H.

[0090] Based on the above actions, the contact body 65c can automatically push the pen refill 7 out of the pen refill 9 with each revolution along the delivery cam surface 54. By repeating this action, the pen refill 7 is pushed out sequentially while being worn down by the writing action.

[0091] In summary, the refill delivery mechanism is configured such that the abutment 65c moves along the delivery cam surface 54 according to the rotation of the rotating body 40, and the sliding member 9 pulls the refill 7 held in the holding chuck 10 out of the ball chuck 11 by the forward movement of the sliding member 9 as the abutment 65c falls into the step 55 of the delivery cam surface 54. The refill delivery mechanism utilizes the step 55 of the delivery cam surface 54 to convert the rotational driving force of the rotating body 40 of the rotation drive mechanism 30 into the delivery action of the refill 7. The structure that creates a height difference on the delivery cam surface 54 is collectively referred to as a "height difference".

[0092] The mechanical pencil 1 is configured such that the lead 7, held in the ball clip 11, is also rotated by the rotational driving force of the rotating body 40 of the rotary drive mechanism 30. Therefore, uneven wear of the lead 7 during writing is prevented, resulting in less significant variation in the thickness and density of the writing line. In summary, the rotary drive mechanism 30 has a rotating body 40 that is driven to rotate in one direction by receiving a backward movement in the axial direction caused by the writing pressure exerted on the lead 7 held by the ball clip 11 and a forward movement in the axial direction caused by the release of the writing pressure.

[0093] In the feed amount adjustment mechanism, as described above, the step height H of the step 55 of the feed cam surface 54 can be changed simply by rotating the dial cam member 50 and the guide cam member 52 relative to each other about the central axis. Therefore, the feed amount of the pen refill 7 of the pen refill feed mechanism can be adjusted more easily and accurately.

[0094] If the degree of wear on the lead 7, caused by differences in writing pressure and the hardness of the lead 7 used depending on the user, is adjusted to be approximately consistent with the amount of lead 7 fed out, then the amount of protrusion of the lead 7's sliding member 9 can be kept constant even while writing. As a result, in the mechanical pencil 1, it is possible to write continuously for a long time with a single press. Preferably, the dial cam 51 or the guide cam 53 is configured such that a step 55 with a step height H that is equivalent to a length exceeding the generally assumed degree of wear on the lead 7 is formed. Thus, the amount of lead 7 fed out can be set to suit the preferences of all users.

[0095] In the above embodiments, the dial cam member 50 is a cylindrical member as the first cam member, but it can also be an annular member. Similarly, the guide cam member 52 is an annular member as the second cam member, but it can also be a cylindrical member. Alternatively, a guide cam 53 can be provided on the first cam member, and a dial cam 51 can be provided on 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 feed cam surface. Furthermore, the step height can be adjusted by moving the first cam member and the second cam member relatively back and forth, i.e., moving them apart in the axial direction.

[0096] Alternatively, the guide rail cam member 52 and the dial cam member 50 can be integrally formed, with the dial cam member forming only a single feed cam surface 54. In this case, the aforementioned feed amount adjustment cannot be performed, but the number of parts is reduced, thus reducing costs. Multiple dial cam members with various step heights H can also be prepared to adjust the feed amount. In this case, the user can select and replace the dial cam member that achieves the most suitable feed amount for themselves.

[0097] Next, refer to Figure 3 , Figure 5 , Figure 6 as well as Figures 16 to 19 The clutch mechanism 60 is described below. The clutch mechanism 60 functions by taking the rotational motion of the rotating body 40 of the rotary drive mechanism 30 (as input) as the rotational motion of the abutment body 65c (as output). The clutch mechanism 60 includes an input member, namely an input clutch cam 61, an output member, namely an output clutch cam 62, a transmission cam 64, and a delivery cam 65. Additionally, the mechanical pencil 1 also includes a clutch cam retainer 66.

[0098] Figure 16 This is a 3D view of the input clutch cam 61. Figure 17 This is a 3D view of the output clutch cam 62. Figure 18 This is an enlarged perspective view illustrating the input clutch cam 61 and the output clutch cam 62. Figure 16 In the middle, the input clutch cam 61 is configured such that the upper part becomes the rear side of the mechanical pencil 1. Figure 17 In the middle, the output clutch cam 62 is configured such that it is positioned above the rear side of the mechanical pencil 1. Figure 18 In the middle, the top is the back of mechanical pencil 1.

[0099] 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.

[0100] 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 is positioned opposite the cam protrusion 61a of the input clutch cam 61. The clutch cam surface 63 includes multiple peaks 63a and multiple valleys 63b with flat bottom surfaces located between adjacent peaks 63a.

[0101] Reference Figure 18The cam protrusion 61a of the input clutch cam 61 has a substantially similar shape to the peak 63a of the output clutch cam 62. The cam protrusion 61a of the input clutch cam 61 has a first engagement surface 61aa that is substantially perpendicular to the rear end face 61b and an inclined first inclined surface 61ab. Similarly, the peak 63a of the output clutch cam 62 has a second engagement surface 63aa that is substantially perpendicular to the bottom surface of the valley 63b and an inclined 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 with the second engagement surface 63aa of the output clutch cam 62.

[0102] Reference Figure 3 , Figure 5 as well as Figure 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 inserted until its rear end face abuts against the flange portion 62a of the output clutch cam 62. The transmission cam 64 is cylindrical, and its front end face has a first engaging protrusion 64a extending forward and evenly spaced along the circumferential direction. A first engaging wall 64b extending along the axial direction is provided on the circumferential side of the first engaging protrusion 64a. An annular protrusion 64c is provided on the inner peripheral surface of the transmission cam 64.

[0103] The input clutch cam 61 is disposed within the transmission cam 64 with its flange 61c positioned 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 restricted by the engagement of the flange 61c with the annular protrusion 64c of the transmission cam 64. The backward movement of the input clutch cam 61 is restricted by the cooperation of the cam protrusion 61a with the clutch cam surface 63 of the output clutch cam 62.

[0104] A feed cam 65 is disposed in front of the transfer 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 transfer cam 64. A second engaging wall 65b is provided along the axial direction on the circumferential side of the second engaging protrusion 65a. 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.

[0105] The slider 9 is inserted into the feed cam 65 from the rear, and the flange 9a can be engaged with the annular protrusion 65d of the feed cam 65. The cam abutment spring 18 is configured such that one end is engaged with the inner surface of the flange 9a of the slider 9 and the other end is engaged with the front end face of the input clutch cam 61. Under the force of the cam abutment spring 18, the slider 9 is forced forward, and the feed cam 65 is forced forward by means of the flange 9a of the forced slider 9. As a result, as described above, the abutment body 65c is forced in a manner that abuts against the feed cam surface 54. The feed cam 65 can move integrally with respect to the slider 9 in the axial direction, and can rotate independently about the central axis.

[0106] The clutch cam retainer 66 is cylindrical and mounted on the inner surface of the pencil barrel 6, specifically the front pencil barrel 2. A high-viscosity grease or other liquid lubricant 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 pencil barrel 6 caused by gravity or other factors. Alternatively, the clutch cam retainer 66 can be integrally formed with the pencil barrel 6. That is, a viscous fluid that inhibits axial movement of the output member is disposed between the output member and the pencil barrel. By having a clutch cam retainer 66 in the mechanical pencil 1, the effects of dimensional deviations or frictional resistance of the components of the clutch mechanism 60 can be absorbed. Furthermore, the clutch cam retainer 66 can be omitted.

[0107] Reference Figure 3 As described above, the outer peripheral surface of the rear end of the fastener 13 of the ball collet 11 is fitted into 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 is fitted into the inner peripheral surface of the rear end of the input clutch cam 61. The rear end of the relay member 12 is connected to the rotating body 40 ( Figure 4 Therefore, the input clutch cam 61 is driven by the rotating body 40 of the rotary drive mechanism 30 via the relay member 12. Additionally, the input clutch cam 61 moves back and forth with the rotating body 40 via the relay member 12 based on the buffering action of the pen refill 7. The relay member 12 passes through the interior of the output clutch cam 62 and the interior of the transmission cam 64, and the output clutch cam 62 and the transmission cam 64 are separated from the relay member 12. Therefore, the rotational motion 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.

[0108] Reference Figure 19As described later, the rotational motion of the input clutch cam 61 is transmitted to the output clutch cam 62 through the cooperation of the cam protrusion 61a and the clutch cam surface 63 of the output clutch cam 62. The rotational motion of the output clutch cam 62 is transmitted to the delivery cam 65 via the connected transfer cam 64. That is, with the rotation of the transfer cam 64, the first engagement wall 64b of the first engagement protrusion 64a and the second engagement wall 65b of the second engagement protrusion 65a engage in the circumferential direction, transmitting the rotational motion of the transfer cam 64 to the delivery cam 65. As a result, as described above, the abutment 65c moves along the delivery cam surface 54, dispensing the pen refill 7.

[0109] Figure 19 This is a schematic diagram illustrating the operation of the clutch mechanism 60 that cooperates with the rotary drive mechanism 30. Figure 19 This is a diagram showing the positional relationship between the rotating body 40 of the rotary drive mechanism 30, the upper cam forming member 41, and the lower cam forming member 42, and the input clutch cam 61 and output clutch cam 62 in the clutch mechanism 60. It is a circumferentially unfolded diagram of a cylindrical surface including each cam surface, about the central axis. Figure 19 In the middle, the top is the back of mechanical pencil 1. Figure 19 (A) to Figure 19 The state of the rotary drive mechanism 30 shown in (E) is the same as Figure 8 (A) to Figure 8 (C) and Figure 9 (D) and Figure 9 The state of the rotary drive mechanism 30 shown in (E) corresponds to that of the rotary body 40 and the output clutch cam 62. Triangular marks indicating the amount of rotational movement are marked on the rotary body 40 and the output clutch cam 62, respectively.

[0110] Figure 19 (A) indicates the relationship between the rotary drive mechanism 30 and the clutch mechanism 60 when no writing pressure is applied to the pen refill 7. The rotary drive mechanism 30 and... Figure 8 This corresponds to the state shown in (A). Therefore, the second cam surface 40b of the rotating body 40 engages with the second fixed cam surface 42a of the lower cam forming member 42. At this time, the cam protrusion 61a of the input clutch cam 61 is separated from the clutch cam surface 63 of the output clutch cam 62 in the axial direction and does not abut. The triangular marks marked on the rotating body 40 and the output clutch cam 62 are arranged on the same straight line in the axial direction.

[0111] then, Figure 19 (B) indicates the initial state where writing pressure has been applied to the pen refill 7. The rotary drive mechanism 30 and... Figure 8This corresponds to the state shown in (B). Therefore, in this state, the rotating body 40 moves towards the upward cam forming member 41, and 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 peak 63a of the output clutch cam 62 (… Figure 18 Separate in the circumferential direction, specifically, separate by a distance D1 in the circumferential direction.

[0112] then, Figure 19 (C) indicates that further writing pressure is applied to the pen refill 7, and the first cam surface 40a of the rotating body 40 is engaged with the first fixed cam surface 41a of the upper cam forming member 41. The rotary drive mechanism 30 and Figure 8 This corresponds to the state shown in (C). Therefore, the rotating body 40 receives a rotational drive equivalent to half a phase (half a pitch) of one tooth of the first cam surface 40a. That is, the rotating body 40... Figure 19 The rotation angle shown in (A) is equivalent to the distance L1 of rotational movement in the circumferential direction. Driven by the rotation of the rotating body 40, the cam protrusion 61a of the input clutch cam 61 engages with the peak 63a of the output clutch cam 62, driving the output clutch cam 62 to rotate via the input clutch cam 61. As previously... Figure 19 As shown in (B), since the cam protrusion 61a of the input clutch cam 61 separates from the peak 63a of the output clutch cam 62 in the circumferential direction, the rotational movement of the output clutch cam 62 is less than the rotational movement of the input clutch cam 61, i.e., the rotating body 40, by a distance L1. Specifically, the rotational movement of the output clutch cam 62 is the distance L2 obtained by subtracting the distance D1 from the distance L1. Therefore, the output clutch cam 62 rotates by a second rotation angle equivalent to the distance L2.

[0113] then, Figure 19 (D) indicates the initial state where the writing pressure relative to the pen refill 7 has been released. The rotary drive mechanism 30 and... Figure 9 This corresponds to the state shown in (D). Therefore, in this state, the rotating body 40 moves towards the downward cam forming member 42 under the force of the buffer spring 45, and the cam protrusion 61a of the input clutch cam 61 separates from the clutch cam surface 63 of the output clutch cam 62.

[0114] then, Figure 19 (E) indicates the state in which the second cam surface 40b of the rotating body 40 meshes with the second fixed cam surface 42a of the lower cam forming member 42 under the force of the buffer spring 45. The rotary drive mechanism 30 and Figure 9This corresponds to the state shown in (E). Therefore, the rotating body 40 again receives a rotational drive equivalent to half a phase (half a pitch) of one tooth of the second cam surface 40b. That is, the rotating body 40 and the input clutch cam 61 connected to the rotating body 40 are driven from... Figure 19 The state shown in (A) rotates by a first rotation angle corresponding to a rotational movement distance L3 equivalent to one phase (one pitch). On the other hand, since the cam protrusion 61a of the input clutch cam 61 separates from the peak 63a of the output clutch cam 62 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 do not engage, and therefore, the output clutch cam 62 is not driven to rotate. Furthermore, the input clutch cam 61 and the output clutch cam 62 are configured such that only the first engagement surface 61aa of the input clutch cam 61 and the second engagement surface 63aa of the output clutch cam 62 cooperate, and the other parts do not cooperate.

[0115] By utilizing the forward and backward movement of the rotating body 40 in the axial direction caused by writing, the rotating body 40 and the input clutch cam 61 perform a rotational movement corresponding to one tooth of the cam of the rotary drive mechanism 30, but the output clutch cam 62 performs a smaller rotational movement. That is, the clutch mechanism 60 is configured to transmit the rotational motion of the input clutch cam 61 to the output clutch cam 62 in such a way that when the input clutch cam 61 rotates by a first rotation angle, the output clutch cam 62 rotates by a second rotation angle smaller than the first rotation angle. The pitch of the cam of the clutch mechanism 60 is set to be smaller than the pitch of the cam of the rotary drive mechanism 30. Specifically, the output clutch cam 62 rotates by the difference between the rotation angle corresponding to one tooth of the cam of the rotary drive mechanism 30 (the first rotation angle) and the rotation angle corresponding to one tooth of the cam of the clutch mechanism 60 (the second rotation angle).

[0116] For example, the number of teeth A of the rotary drive mechanism 30, such as the first cam surface 40a of the rotating body 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 rotating body 40 to rotate one revolution, i.e., the number of strokes to be written, is 40. The rotation angle C of the rotating body 40 for each stroke is 360 / A, therefore it becomes 360 / 40 = 9 degrees. The rotation angle D of the output clutch cam 62, corresponding to the distance to the adjacent peak 63a, is 360 / B, therefore it becomes 360 / 46 = 7.83 degrees. Thus, as referred to Figure 19As explained, the rotation angle E of the output clutch cam 62 for each revolution is CD, which is 9 - 7.83 = 1.17 degrees. Therefore, the number of revolutions required for the output clutch cam 62 to rotate one revolution is 360 / 1.17 = 307.7 revolutions, totaling 308 revolutions. If expressed in terms of the reduction ratio, it becomes 1 / (C / E) = 1 / 7.69.

[0117] According to the clutch mechanism 60, the number of strokes required for the output clutch cam 62 and the abutment body 65c of the delivery cam 65 to rotate one revolution (e.g., 308 strokes) is greater than the number of strokes required for the rotating body 40 to rotate one revolution (e.g., 40 strokes). In addition, 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 rotating body 40 can rotate one revolution with any number of strokes and the pen refill can be delivered with any number of strokes.

[0118] Alternatively, the output clutch cam 62 and the transmission cam 64 can be integrally formed. Alternatively, the output clutch cam 62, the transmission cam 64, and the delivery cam 65 can be combined into an output component. Alternatively, the slider 9 and the delivery cam 65 can be integrally formed. The input clutch cam 61 has one cam protrusion 61a as the input cam surface, but it can also have multiple cam protrusions 61a. The input cam surface of the input clutch cam 61 and the clutch cam surface 63 of the output clutch cam 62, which serves as the output cam surface, can be arbitrarily formed as long as they engage during circumferential movement, as in the relationship between the first engagement surface 61aa and the second engagement surface 63aa, and do not engage during axial movement. Similarly, the transmission cam 64 and the delivery cam 65 can be arbitrarily formed as long as they engage during circumferential movement, as in the relationship between the first engagement wall 64b and the second engagement wall 65b, and do not engage during axial movement.

[0119] In the above embodiment, an input clutch cam 61 and an output clutch cam 62 are used as the input and output components, respectively. That is, the clutch mechanism 60 is configured such that an input cam surface is formed on the input component and an output cam surface opposite to the input cam surface is formed on the output component. The input cam surface and the output cam surface engage only when a part of the rotating body rotates, and the rotational motion of the rotating body is transmitted to the output component via the input component.

[0120] However, a friction clutch can also be used as the clutch mechanism. That is, the input and output components can be arranged such that the circular or conical components are positioned opposite each other, and friction is used to cause the rotational motion of the rotating body 40 via the relay component 12 to be configured such that when the input component rotates by a first rotation angle, the output component rotates by a second rotation angle smaller than the first rotation angle. The friction force applied to the input and output components can be adjusted by changing the shape, material, surface roughness, etc., of the contact surfaces between the opposing circular or conical components, thereby adjusting the rotation angle transmitted from the input component to the output component. This allows the rotating body 40 to rotate one revolution in any number of strokes and the pen refill to be delivered in any number of strokes. The contact surfaces between the input and output components can also be made of materials such as rubber or sandpaper. In addition to engagement clutches and friction clutches, any other clutch mechanism can be used.

[0121] In the above embodiment, the ball chuck 11 is configured such that, since it is connected to the input clutch cam 61, the ball chuck 11 receives the rotational driving force of the rotating body 40 via the relay member 12 and the input clutch cam 61, thereby rotating the lead 7. However, the ball chuck 11 and the input clutch cam 61 may not be connected. In summary, the clutch mechanism can also be applied to mechanical pencils that are not configured to rotate the lead.

[0122] After the pen refill 7 is pulled out of the ball clamp 11 by the click operation or the refill delivery mechanism, and before writing pressure is applied to the pen refill 7, the pen refill has room to retract further (recoil) in its construction. Therefore, when the actual amount of pen refill 7 delivered is small, due to recoil, the delivered pen refill 7 retracts, and there is a situation where the pen refill 7 is not actually delivered.

[0123] According to the clutch mechanism, the timing or frequency of lead 7 delivery by the lead delivery mechanism can be delayed. Therefore, according to the clutch mechanism, more lead 7 can be delivered after the lead 7 wears out, preventing the lead 7 from being substantially not delivered due to backlash. The lead delivery amount can be changed 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 can deliver lead more reliably can be provided.

[0124] like Figure 1 As shown, the mechanical pencil 1 includes a clip 70a and a cap 70 that engages with the barrel 6. The cap 70 includes a cap cover 71, a lead delivery member 72 serving as a lead delivery section, and a buffer spring 73. In this specification, the closed end side is designated as the "front" side and the open end side as the "rear" side along the axial direction of the cap 70. (Refer to...) Figure 20 and Figure 21This describes the pen refill delivery mechanism that utilizes the pen refill delivery section of the pen cap 70.

[0125] like Figure 1 and Figure 21 As shown in (B), the pen cap 71 is a cap-shaped component with its front end closed. The pen cap 71 is attached to the front end of the pen cap 70, thus forming the closed end of the pen cap 70. The refill delivery member 72 is configured to move back and forth within the front end of the pen cap 70. A buffer spring 73 is disposed between the pen cap 71 and the refill delivery member 72, and the buffer spring 73 applies a rearward force to the refill delivery member 72.

[0126] Figure 20 This is a longitudinal sectional view of the pen refill delivery component 72. The pen refill delivery component 72 is a cylindrical component. Figure 20 In the center, the pen cap 70 is positioned so that it is on the left side, forming the front side. An insertion hole 72a, with a circular opening, is provided on the rear end face of the lead delivery member 72 for inserting the tip of the mechanical pencil 1, i.e., the slider 9, etc. The bottom surface of the insertion hole 72a has a cylindrical inner circumferential surface with an inner diameter R narrower than the entrance of the insertion hole 72a and a depth D2. A conical surface 72c is provided behind the receiving recess 72b. The inner diameter R of the receiving recess 72b is set according 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 set to receive the tip of the lead 7.

[0127] Figure 21 This is an enlarged cross-sectional view illustrating the feeding of the mechanical pencil 1 from the lead 7. Figure 21 (A) indicates the state of the mechanical pencil 1 before the cap 70 is engaged with the barrel 6 and the lead 7 is dispensed. Figure 21 (B) indicates the state of the mechanical pencil 1 where the cap 70 is engaged with the barrel 6. Figure 21 (C) indicates the state of the mechanical pencil 1 after the lead 7 is dispensed following the removal of the cap 70 from the barrel 6.

[0128] exist Figure 21 In (A), the pen refill 7 does not protrude from the self-sliding member 9. That is, it shows the state in which the pen refill 7 is retracted in a way that prevents the self-sliding member 9 from protruding after the user has finished a series of writing actions.

[0129] Next, as Figure 21As shown in (B), the pen cap 70 is fitted into the pen barrel 6. At this time, the tip of the mechanical pencil 1, i.e., the tip of the lead 7 and the tip of the slider 9, is inserted into the insertion hole 72a of the lead delivery member 72. As described above, the inner diameter R of the receiving recess 72b is set according to the outer diameter of the lead 7, so the receiving recess 72b receives the tip of the lead 7. On the other hand, the outer diameter of the tip of the slider 9 is set to be larger than the inner diameter R of the receiving recess 72b. Therefore, the tip of the slider 9 is locked with the conical surface 72c as it is inserted into the pen cap 70, and is not received in the receiving recess 72b. As a result, the slider 9 retracts relative to the lead 7 in the pen barrel 6, and the lead 7 protrudes from the tip of the slider 9 in the pen cap 70 by a length equal to the depth D2 of the receiving recess 72b.

[0130] Next, as Figure 21 As shown in (C), to begin the next writing action, the pen cap 70 is detached from the pen barrel 6. At this time, the retracted slider 9 and the retaining clip 10 disposed inside the slider 9 advance under the force of the cam abutting the spring 18. As a result, the pen refill 7 held in the retaining clip 10 is pulled out from the ball clip 11 and is delivered from the top of the slider 9 by an amount corresponding to the depth D2 of the receiving recess 72b. Therefore, the amount of pen refill 7 delivered, i.e., the delivery amount, is equal to the depth D2 of the receiving recess 72b.

[0131] Normally, when a user finishes a series of writing actions, the lead is retracted in a manner that prevents it from protruding from the tip or slider to protect the lead. Therefore, at least one click is required to pre-feed the lead before starting the next writing action. Even mechanical pencils with the aforementioned lead-feeding mechanism still require a writing action to automatically feed the lead; therefore, at least one click is required to pre-feed the lead before starting the writing action.

[0132] According to the lead delivery member 72, the lead 7 can be delivered simply by attaching or detaching the cap 70 relative to the pencil barrel 6. That is, the lead can be delivered without needing to press the button before starting writing. Therefore, a mechanical pencil that can perform a new lead delivery operation different from conventional pressing operations can be provided.

[0133] Furthermore, assuming the pen cap 70 is fitted into the pen barrel 6 with the pen refill 7 protruding from the sliding member 9 a greater distance than the depth D2 of the receiving recess 72b, the amount of protrusion of the pen refill 7 will not change. That is, in this state, the top end of the sliding member 9 will not be locked against the conical surface 72c, and therefore, the sliding member 9 will not retract relative to the pen refill 7 within the pen barrel 6. At this time, the pen refill delivery member 72 is pressed by the longer protruding top end of the pen refill 7, and the pen refill delivery member 72 advances against the force of the buffer spring 73, thereby absorbing the pressure.

[0134] The refill delivery member 72 can also be replaced by removing the pen cap 71. That is, the amount of refill 7 protrusion varies depending on the user's preference. For example, some users find it convenient to write for extended periods with a fully protruding refill 7, while others prefer a less protruding refill 7 to avoid worrying about it breaking. Therefore, refill delivery members 72 with various depths D2 of storage recesses 72b can be pre-prepared and replaced according to the user's preference. The buffer spring 73 can also be omitted, and the refill delivery member 72 can be fixedly disposed inside the front end of the pen cap 70.

[0135] The refill delivery part of the refill delivery member 72 can be configured arbitrarily as long as it can press the slider 9 to retract relative to the refill 7 when the pen cap 70 is fitted into the pen barrel 6. That is, the shape of the receiving recess 72b can be arbitrarily configured as long as the tip of the refill 7 is received in the receiving recess 72b when the pen cap 70 is fitted, and the tip of the slider 9 is locked and retracted when it is not received in the receiving recess 72b. For example, it can also be a plurality of protrusions extending inward on the inner circumferential surface of the pen cap 70 in such a way that the slider 9 retracts relative to the refill 7 when the pen cap 70 is fitted.

[0136] In the above embodiment, the slider 9 is forced forward by the cam abutting the spring 18 as the lead delivery mechanism functions. However, the lead delivery member 72 of the cap 70 can also be applied to a mechanical pencil where the slider is not forced forward. The mechanical pencil may or may not have a ball clip. For example, the lead delivery member of the cap can also be applied to a tube-sliding mechanical pencil that operates in such a way that, simultaneously with the protrusion of the lead accompanying the press operation, the tubular lead guide mounted on the tip member, which serves as the slider, also advances, and simultaneously with the wear of the lead accompanying writing, the lead guide also retracts.

[0137] Figure 22 This is an enlarged perspective view of the pen cap 70. On the inner circumferential surface of the pen cap 70, specifically near the opening end, are a plurality of, specifically three, positioning recesses 70b arranged at equal intervals along the circumferential direction. Each positioning recess 70b is a rearward-facing recess, forming a bell-shaped curve when viewed radially outward from the central axis. Specifically, a convex curved surface 70ba is formed on the inner surface of the front side of the positioning recess 70b, and a concave curved surface 70bb is formed on the inner surface of the rear side of the positioning recess 70b.

[0138] Figure 23 This is a magnified 3D view of pen barrel 6. (For example...) Figure 23 as well as Figure 2As shown, the outer peripheral surface of the pen barrel 6 has a plurality of, specifically three, positioning protrusions 6a arranged at equal intervals along the circumferential direction. Each positioning protrusion 6a extends forward. A convex curved surface 6aa is partially formed on the outer surface of the positioning protrusion 6a on its front side. The convex curved surface 6aa of the positioning protrusion 6a is partially complementary to the convex curved surface 70ba of the positioning recess 70b. That is, the positioning protrusion 6a and the positioning recess 70b have complementary portions.

[0139] like Figure 1 and Figure 21 As shown in (B), a ring-shaped magnet 80 is disposed inside the pen cap 70. The magnet 80 is, for example, a neodymium magnet. Alternatively, instead of a ring-shaped magnet 80, multiple magnets may be arranged at equal intervals along the circumference. On the other hand, the aforementioned grip portion 8 is a first magnetic body made of magnetic material. The magnet 80 is disposed inside the pen cap 70 such that an attraction generated by magnetic force acts between it and the grip portion 8 when the pen cap 70 is fitted into the pen barrel 6.

[0140] When fitting the pen cap 70 into the pen barrel 6, typically, one hand holds the pen barrel 6 and the other hand holds the pen cap 70, inserting the open end of the pen cap 70 relative to the pen barrel 6. When the pen cap 70 is inserted to a predetermined depth relative to the pen barrel 6, the pen cap 70 is pulled in deeper under the action of the magnetic force acting between the grip 8 and the magnet 80. At this time, if the positioning protrusion 6a of the pen barrel 6 and the positioning recess 70b of the pen cap 70 are aligned along the axial direction, the positioning protrusion 6a and the positioning recess 70b will fit together without interfering with each other, thus fitting the pen barrel 6 and the pen cap 70 together. On the other hand, there is a case where the positioning protrusion 6a of the pen barrel 6 and the positioning recess 70b of the pen cap 70 are not aligned along the axial direction, that is, they are misaligned in the circumferential direction.

[0141] When the positioning protrusion 6a of the pen barrel 6 and the positioning recess 70b of the pen cap 70 are slightly misaligned in the circumferential direction, they are attracted by magnetic force, causing the convex surface 6aa of the positioning protrusion 6a to abut against the concave surface 70bb of the positioning recess 70b. As a result, the positioning protrusion 6a and the positioning recess 70b cooperate to rotate the pen barrel 6 or the pen cap 70 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 pen barrel 6 and the pen cap 70.

[0142] When the positioning protrusion 6a of the pen barrel 6 and the positioning recess 70b of the pen cap 70 are significantly misaligned in the circumferential direction, even under the attraction generated by magnetic force, the convex surface 6aa of the positioning protrusion 6a and the concave surface 70bb of the positioning recess 70b will not come into contact. Therefore, the positioning protrusion 6a and the positioning recess 70b will not cooperate, and the pen barrel 6 and the pen cap 70 will not engage. Here, by holding the pen cap 70 with one hand, the pen cap 70 is rotated around the central axis until the convex surface 6aa of the positioning protrusion 6a and the concave surface 70bb of the positioning recess 70b come into contact. As a result, the positioning protrusion 6a and the positioning recess 70b cooperate, and the pen barrel 6 or the pen cap 70 is rotated around the central axis in such a way that the positioning protrusion 6a and the positioning recess 70b engage, thus engaging the pen barrel 6 and the pen cap 70.

[0143] Generally, the pen barrel and cap are engaged by a snap-fit ​​mechanism, where a protrusion formed on the inner circumferential surface of the cap extends beyond a protrusion formed on the outer circumferential surface of the barrel. According to the above embodiment, the engagement of the pen barrel 6 and cap 70 utilizes an attractive force generated by magnetism, thus eliminating the need to forcefully press the cap 70 against the pen barrel 6. Consequently, even when the cap 70 is inserted at an angle relative to the central axis of the pen barrel 6, the outer circumferential surface of the pen barrel 6 will not be damaged by the edge of the open end of the cap 70. Furthermore, even children or the elderly with limited strength can easily engage the pen barrel 6 and cap 70.

[0144] Furthermore, when the pen barrel 6 and the pen cap 70 are marked with symbols, text, patterns, or other identifying displays, designs, or characteristic shapes covering the outer surfaces of both, the pen barrel 6 and the pen cap 70 can be correctly positioned in the direction of rotation around the central axis. In summary, according to the above embodiment, a writing instrument that allows the pen cap to accurately engage with the pen barrel can be provided. Moreover, since the magnetic force is stronger the closer the relative distance, the pen barrel 6 and the pen cap 70 collide forcefully upon engagement. As a result, the user can feel a comfortable locking sensation and hear a locking sound, recognizing that the engagement has been reliably completed.

[0145] In addition, such as Figure 1 , Figure 2 as well as Figure 4As shown, a second magnetic body 81 made of magnetic material can also be provided at the rear end of the pen barrel 6, i.e., the rear end of the pen barrel 3. Therefore, even when the pen cap 70 is fitted into the rear end of the pen barrel 6 for writing, the attractive force generated by the magnet can be utilized. In this case, a positioning protrusion 6a cooperating with the positioning recess 70b of the pen cap 70 can also be provided at the rear end of the pen barrel 6. In the above embodiment, the positioning protrusion 6a is formed on the outer peripheral surface of the pen barrel 6, and the positioning recess 70b is formed on the inner peripheral surface of the pen cap 70. However, it is also possible to form the positioning recess on the outer peripheral surface of the pen barrel 6 and the positioning protrusion on the inner peripheral surface of the pen cap 70. Furthermore, the mechanical pencil 1 may not have the second magnetic body 81.

[0146] In the above embodiment, a magnet 80 is disposed on the cap 70 side, and a first magnetic body is disposed on the barrel 6 side instead of a magnet. However, it is also possible to dispose of the first magnetic body on the cap 70 side and to dispose of the magnet on the barrel 6 side, for example, inside the grip portion 8. However, since the grip portion 8 is exposed to the outside when the cap 70 is removed, it is preferable to dispose of the first magnetic body on the barrel 6 side to prevent surrounding magnetic objects, such as clips on a table, from being attracted by the grip portion 8. Magnets may also be disposed on both the barrel 6 and the cap 70. The first magnetic body may also be disposed on a portion of the barrel 6 other than the grip portion 8.

[0147] In the above embodiment, three positioning protrusions 6a and three positioning recesses 70b are formed, but there can be one, two, or more than four. The positioning protrusions 6a and 70b cooperate with each other as long as they are slightly offset in the circumferential direction, allowing the pen barrel 6 or pen cap 70 to rotate around the central axis and engage with the pen cap 70. They can also be configured arbitrarily. For example, they can also be... Figure 23 The positioning protrusion 6a shown is formed with Figure 22 The positioning recesses 70b shown are completely complementary.

[0148] The aforementioned method of using the attractive force generated by the magnetism between the pen barrel and the cap can be applied 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. Alternatively, the positioning protrusion 6a and positioning recess 70b can be omitted, and the writing instrument can be designed to use only the attractive force generated by magnetism to engage the pen barrel and cap.

[0149] Figure 24 This is a 3D diagram of the clamp 10. Figure 25 This is a longitudinal sectional view of the retainer chuck 10. Figure 25In the center, the mechanical pencil 1 is positioned so that its left side forms the front side. As described above, a through hole 10a extending along the axial direction is formed in the retaining clip 10. The retaining clip 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 lead-holding portion 10d, which is narrower than other portions, is provided inside the front side of the through hole 10a. A conical surface 10e that extends rearward is provided inside the through hole 10a behind the lead-holding portion 10d.

[0150] like Figure 24 As shown, 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 can be an elongated hole, its cross-sectional shape can also be oval, specifically, it can be oblong or elliptical. The dimensions of the elongated hole, such as the length or aspect ratio in the case of a rounded rectangle, or the lengths of the major and minor axes in the case of an ellipse, are determined in advance through experiments, etc., based on the outer diameter of the lead 7 generally used in the mechanical pencil 1 or the composition of the lead 7.

[0151] 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, while an elongated hole is as difficult to elastically deform as a round hole in the direction along its elongated shape, it is more prone to elastic deformation in the direction orthogonal to the elongated shape's extension direction compared to a round hole. Therefore, even if there are slight deviations in the outer diameter of the lead 7 or the size of the through hole in the holding clip 10 during manufacturing, these deviations can be absorbed by elastic deformation in the direction orthogonal to the elongated shape's extension direction. Thus, a mechanical pencil can be provided that allows for a more appropriate setting of the sliding resistance between the lead 7 and the holding clip 10.

[0152] In typical mechanical pencils, the sliding contact between the lead and the retaining clip occurs only when the lead is ejected using a press 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 when the lead 7 is ejected using a press operation, but also during normal writing. Therefore, in order for the rotary drive mechanism and the lead ejection mechanism to function properly, it is preferable to set the sliding resistance between the lead and the retaining clip more precisely. In the mechanical pencil 1, since the lead holding portion 10d of the through hole 10a is an elongated hole, the sliding resistance between the lead 7 and the retaining clip 10 can be set more precisely.

[0153] The retainer 10 is made of elastic materials such as NBR, EPDM, fluororubber, or silicone rubber. In particular, from the viewpoint of creep resistance and chemical resistance, a retainer 10 made of fluororubber is preferred. That is, while the pen refill 7 contains some oil, by making the retainer 10 from fluororubber, the influence of the oil can be further reduced. As a result, various types and combinations of oil components can be selected for the pen refill 7, enabling the manufacture of more diverse pen refills. In this case, the pen refill retainer 10d may not be an elongated hole, but may have a general circular cross-sectional shape.

[0154] In the above embodiment, the retaining clip 10 has a cylindrical small-diameter portion 10b, but the retaining clip can also be formed as a whole into a conical shape. In short, the retaining clip 10 can be arbitrarily configured in shape as long as the pen refill holding portion 10d of the through hole 10a is an elongated hole.

[0155] Explanation of reference numerals in the attached figures

[0156] 1. Mechanical pencil; 2. Front barrel; 3. Rear barrel; 4. Tip component; 6. Barrel; 6a. Positioning protrusion; 7. Lead; 8. Holding part (first magnetic body); 9. Sliding part; 10. Holding clip; 10a. Through hole; 10d. Lead holding part; 11. Ball clip; 12. Relay component; 17. Coil spring; 18. Cam abutment spring; 19. Lead shell; 20. Press rod; 21. Coil spring; 30. Rotary drive mechanism; 40. Rotating body; 50. Dial cam component; 51. Dial cam; 52. Guide rail Cam component; 53, guide cam; 54, delivery cam surface; 55, step; 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, abutment body; 66, clutch cam retainer; 70, pen cap; 70b, positioning recess; 71, pen cap cover; 72, pen refill 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 chuck that allows advancement of a lead and prevents retreat of the lead; a rotational drive mechanism that has a rotating body, receives a retreat motion in an axial direction of the rotating body that is generated by a writing pressure received by the lead held by the ball chuck, and a forward motion in the axial direction of the rotating body that is generated by release of the writing pressure, and drives the rotating body to rotate in one direction; a feed cam surface that has a ring-shaped cam surface and a drop provided in the axial direction of the ring-shaped cam surface; an input member that rotates by receiving a rotational drive force of the rotating body; and an output member that has an abutting member that abuts against the feed cam surface and a sliding member that has a holding chuck that holds the lead, the mechanical pencil being configured so that the abutting member moves along the feed cam surface according to rotation of the output member, and the lead held by the holding chuck is pulled out from the ball chuck by a forward motion of the sliding member when the abutting member drops into the drop, the mechanical pencil further comprising a clutch mechanism that transmits a rotational motion of the input member to the output member in such a manner that the output member rotates a second rotational angle that is smaller than a first rotational angle when the input member rotates the first rotational angle.

2. The mechanical pencil according to claim 1, characterized in that: the clutch mechanism is a meshing clutch or a friction clutch.

3. The mechanical pencil according to claim 1, characterized in that: the clutch mechanism is a meshing clutch, an input cam surface is formed in the input member, and an output cam surface that opposes the input cam surface is formed in the output member, the input cam surface and the output cam surface engage only when a part of a rotational motion of the rotating body, the rotational motion of the rotating body is transmitted to the output member via the input member.

4. The mechanical pencil according to claim 3, characterized in that: the rotational drive mechanism has a first cam forming member and a second cam forming member, the rotating body is formed in a circular ring shape and has a first cam surface and a second cam surface formed in an axial direction of the rotating body at one end surface and the other end surface, respectively, and the rotational drive mechanism is provided with a first fixed cam surface formed in the first cam forming member so as to oppose the first cam surface and a second fixed cam surface formed in the second cam forming member so as to oppose the second cam surface, the rotational drive mechanism is configured so that, by a retreat motion of the ball chuck that is generated by the writing pressure, the first cam surface of the rotating body abuts against and engages with the first fixed cam surface, and by release of the writing pressure, the second cam surface of the rotating body abuts against and engages with the second fixed cam surface. ​ ​ In a state where the first cam surface of the rotating body engages with the first fixed cam surface, the second cam surface of the rotating body and the second fixed cam surface are set in a phase-shifted relationship with respect to one tooth of a cam in the axial direction, and in a state where the second cam surface of the rotating body engages with the second fixed cam surface, the first cam surface of the rotating body and the first fixed cam surface are set in a phase-shifted relationship with respect to one tooth of a cam in the axial direction. The pitch of the cam of the clutch mechanism is set to be smaller than the pitch of the cam of the rotation drive mechanism.

5. The propelling pencil according to any one of claims 1 to 4, wherein The ball holder is configured to rotate by receiving the rotation drive force of the rotating body, thereby rotating the lead.

6. The propelling pencil according to any one of claims 1 to 5, wherein A viscous fluid that suppresses movement of the output member in the axial direction is disposed between the output member and the barrel.

7. The propelling pencil according to any one of claims 1 to 5, wherein The propelling pencil is configured to adjust the amount of lead feed by adjusting the height of the drop.

8. The propelling pencil according to claim 7, wherein The propelling pencil further includes a first cam member that is annular or cylindrical, and a second cam member that is annular or cylindrical and is disposed radially outward of the first cam member, and the first cam member and the second cam member cooperate to form the feed cam surface.

9. The propelling pencil according to claim 8, wherein The height of the drop is adjusted by relatively rotating the first cam member and the second cam member about the central axis.

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