Mechanical pencil

Abstract

To provide a mechanical pencil whose cap can be removed with one rotational motion.SOLUTION: A mechanical pencil 10 includes a lead accommodating portion 40 capable of accommodating a writing lead 80, a holding member 50 attached to the lead accommodating portion 40 and holding an accessory 15, and an operating body 60 attached to the holding member 50. The operating body 60 has an engagement groove 61 and the holding member 50 has an engagement protrusion 53 engageable with the engagement groove 61. When the operating body 60 moves rearward relative to the lead accommodating portion 40 while the engagement protrusion 53 is positioned at one end 62 of the engagement groove 61, the holding member 50 and the operating body 60 disengage from the lead accommodating portion 40 with the engagement protrusion 53 remaining engaged with the engagement groove 61, and when the operating body 60 moves rearward relative to the lead accommodating portion 40 while the engagement protrusion 53 is positioned at the other end 63 of the engagement groove 61, the engagement protrusion 53 disengages from the engagement groove 61 and the operating body 60 disengages from the holding member 50.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Conventionally, mechanical pencils are known that have an attachment such as an eraser attached to the rear portion. In order to prevent the attachment from getting dirty, a cap that covers the attachment is attached to the rear end of the mechanical pencil. In such mechanical pencils, it is possible to refill the writing lead by first removing the cap and then removing the attachment.

[0003] Patent Document 1 discloses a mechanical pencil equipped with an accessory holding member that is attached to the rear end of the lead tank and holds an accessory. In this mechanical pencil, the cap is attached to the rear end of the accessory holding member by screw connection. In this mechanical pencil, the accessory holding member and the cap are removed together from the lead tank by pulling the cap backward relative to the barrel, which makes it possible to refill the writing lead. In addition, the cap can be removed from the accessory holding member by rotating the cap around the central axis relative to the barrel to loosen the screw connection between the cap and the accessory holding member. In this state, the accessory, which is an eraser, becomes usable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-151051 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, in the mechanical pencil disclosed in Patent Document 1, the cap is attached to the accessory holding member by screw connection. In this case, when removing the cap from the accessory holding member, it may be necessary to change the grip of the cap and rotate the cap several times.

[0006] The present invention has been made in consideration of the above points, and has an object to provide a mechanical pencil whose cap can be removed with a single rotation motion. [Means for solving the problem]

[0007] The mechanical pencil of the present invention is [1] A lead housing capable of housing a writing lead; A holding member that is attached to the core housing and holds an accessory; An operation body attached to the holding member, The operation body has an engagement groove, The holding member has an engagement protrusion that can be engaged with the engagement groove, When the engagement protrusion is located at one end of the engagement groove, if the operation body moves backward with respect to the lead accommodating portion, the holding member and the operation body are disengaged from the lead accommodating portion while the engagement protrusion remains engaged with the engagement groove, This is a mechanical pencil in which, when the engagement protrusion is located at the other end of the engagement groove and the operating body moves rearward relative to the lead accommodating portion, the engagement protrusion disengages from the engagement groove and the operating body disengages from the holding member.

[0008] The mechanical pencil of the present invention is [2] The mechanical pencil according to [1], wherein the engagement groove extends in a circumferential direction.

[0009] The mechanical pencil of the present invention is [3] The mechanical pencil according to [1] or [2], wherein the engagement groove is configured so that the engagement protrusion can move within an angular range of 20 degrees or more and 70 degrees or less around the central axis.

[0010] The mechanical pencil of the present invention is [4] The mechanical pencil according to any one of [1] to [3], wherein the operating body has a guide portion that guides the engagement protrusion toward the engagement groove when the operating body is attached to the holding member.

[0011] The mechanical pencil of the present invention is [5] The mechanical pencil described in [4], wherein the guide portion includes a first inclined surface extending in a direction inclined with respect to both the axial and circumferential directions so as to move toward one circumferential side toward the rear, and a second inclined surface extending in a direction inclined with respect to both the axial and circumferential directions so as to move toward the other circumferential side toward the rear.

[0012] The mechanical pencil of the present invention is [6] A mechanical pencil as described in any one of [1] to [5], having a rotation regulating portion that regulates rotation of the operating body relative to the holding member when the engagement protrusion is positioned at the one end of the engagement groove.

[0013] The mechanical pencil of the present invention is [7] The mechanical pencil according to [6], wherein the rotation regulating portion includes a regulating groove provided on the operating body and a regulating protrusion provided on the holding member.

[0014] The mechanical pencil of the present invention is [8] The mechanical pencil according to [7], wherein the holding member has an elastic deformation portion including the regulating protrusion.

[0015] The mechanical pencil of the present invention is [9] A barrel that accommodates the lead accommodating portion, The barrel has a barrel side groove extending in the axial direction, The mechanical pencil according to any one of [1] to [8], wherein the holding member has a slide protrusion configured to be axially slidable within the barrel side groove.

[0016] The mechanical pencil of the present invention is

[10] The mechanical pencil according to any one of [1] to [9], wherein the operating body has a rolling prevention portion protruding radially outward.

[0017] The mechanical pencil of the present invention is

[11] A lead housing capable of housing a writing lead; A holding member that is attached to the core housing and holds an accessory; An operation body attached to the holding member, When the operating body moves backward with respect to the lead accommodating portion without rotating with respect to the holding member, the holding member and the operating body are disengaged from the lead accommodating portion, This is a mechanical pencil in which, when the operating body rotates through an angle range of 20 degrees or more and 70 degrees or less with respect to the holding member and then moves rearward with respect to the lead accommodating section, the operating body comes off the holding member. Effect of the Invention

[0018] According to the present invention, it is possible to provide a mechanical pencil whose cap can be removed with a single rotation motion. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram showing one embodiment of the present invention, and is an external view showing an example of a mechanical pencil. [Diagram 2] FIG. 2 is a vertical cross-sectional view of the mechanical pencil of FIG. [Diagram 3] FIG. 3 is a partially enlarged view of FIG. [Figure 4] FIG. 4 is a diagram showing a part of a lead container and a holding member of a mechanical pencil. [Figure 5A] FIG. 5A is a vertical cross-sectional view showing the operating body of the mechanical pencil. [Figure 5B] FIG. 5B is a vertical cross-sectional view showing the operating body of the mechanical pencil. [Figure 6A]FIG. 6A is an external view showing a part of the mechanical pencil in a state in which the holding member and the operating body are attached to the lead housing. [Figure 6B] FIG. 6B is a vertical cross-sectional view showing a part of the mechanical pencil in a state in which the holding member and the operating body are attached to the lead housing. [Figure 6C] FIG. 6C is a diagram showing the positional relationship between the engagement protrusion of the holding member and the engagement groove of the operating body in a state in which the holding member and the operating body are attached to the lead housing part. [Figure 7A] FIG. 7A is an external view showing a part of the mechanical pencil in a state in which the holding member and the operation body are being removed and attached. [Figure 7B] FIG. 7B is a vertical cross-sectional view showing a part of the mechanical pencil in a state in which the holding member and the operating body are being removed and attached. [Figure 8A] FIG. 8A is an external view showing a part of the mechanical pencil with the holding member and the operating body removed from the lead housing. [Figure 8B] FIG. 8B is a vertical cross-sectional view showing a part of the mechanical pencil in a state where the holding member and the operating body have been removed from the lead housing. [Figure 9A] FIG. 9A is an external view showing a part of the mechanical pencil in a state in which the operation body is being removed and attached. [Figure 9B] FIG. 9B is a vertical cross-sectional view showing a part of the mechanical pencil in a state in which the operation body is being removed and attached. [Figure 9C] FIG. 9C is a diagram showing the positional relationship between the engagement protrusion of the holding member and the engagement groove of the operation body in the state shown in FIGS. 9A and 9B. [Figure 10A] FIG. 10A is an external view showing a part of the mechanical pencil in a state where the operating body is detached from the holding member. [Figure 10B] FIG. 10B is a vertical cross-sectional view showing a part of the mechanical pencil in a state where the operating body has been detached from the holding member. [Figure 11A] FIG. 11A is an external view showing a part of the mechanical pencil in a state in which the operation body is in the process of being attached to a holding member. [Figure 11B]FIG. 11B is a vertical cross-sectional view showing a part of the mechanical pencil in a state in which the operation body is in the middle of being attached to the holding member. [Figure 11C] FIG. 11C is a diagram showing the positional relationship between the engagement protrusion of the holding member and the engagement groove of the operation body in the state shown in FIGS. 11A and 11B. [Figure 12A] FIG. 12A is an external view showing a part of the mechanical pencil in a state in which the operation body is in the process of being attached to a holding member. [Figure 12B] FIG. 12B is a vertical cross-sectional view showing a part of the mechanical pencil in a state in which the operation body is in the middle of being attached to the holding member. [Figure 12C] FIG. 12C is a diagram showing the positional relationship between the engagement protrusion of the holding member and the engagement groove of the operation body in the state shown in FIGS. 12A and 12B. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to this specification, the scale and the aspect ratio are appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and understanding.

[0021] In addition, terms used in this specification that specify shapes, geometric conditions, and the extent thereof, such as "parallel," "orthogonal," and "same," as well as values ​​of length and angle, are not to be bound by strict meanings, but are to be interpreted to include a range within which similar functions can be expected.

[0022] In this specification, the direction in which the central axis A of the mechanical pencil 10 extends (longitudinal direction, vertical direction in a longitudinal cross-sectional view) is the axial direction da, the direction perpendicular to the axial direction da is the radial direction, and the direction along the circumference around the central axis A is the circumferential direction dc. In addition, along the axial direction da, the side approaching the writing surface such as a paper surface when writing is the front, and the side moving away from the writing surface is the rear. In addition, along the radial direction, the side approaching the central axis A is the inside or inner side, and the side moving away from the central axis A is the outside or outer side.

[0023] Fig. 1 is a diagram showing one embodiment of the present invention, and is an external view showing an example of a mechanical pencil 10. Fig. 2 is a vertical cross-sectional view of the mechanical pencil 10. Fig. 3 is a partially enlarged view of Fig. 2.

[0024] The mechanical pencil 10 of this embodiment includes a barrel 20, an advancing mechanism 30, a holding member 50, an operating body 60, and an attachment 15.

[0025] The barrel 20 extends in the axial direction da along the central axis A of the mechanical pencil 10. Therefore, the central axis of the barrel 20 coincides with the central axis A of the mechanical pencil 10. An advancing mechanism 30 is disposed inside the barrel 20. The barrel 20 has a barrel body 22 and a tip member 26 connected to the front end of the barrel body 22.

[0026] The barrel body 22 is a member having a substantially cylindrical shape, and is intended to be held by the user's fingers when writing with the mechanical pencil 10. The barrel body 22 may be composed of one member, or may be composed of multiple members. For example, the barrel body 22 may include a front shaft and a rear shaft disposed behind the front shaft. The barrel body 22 may also include an inner shaft and a grip portion disposed outside the inner shaft. The grip portion is a portion that is held by the user's fingers when writing with the mechanical pencil 10.

[0027] The barrel body 22 of this embodiment has a barrel side groove 24. The barrel side groove 24 is a groove formed on the inner surface of the barrel body 22. The barrel side groove 24 extends linearly from the rear end of the barrel body 22 along the axial direction da (see FIG. 6A). In this embodiment, the barrel side groove 24 is a groove formed penetrating the barrel body 22 in the radial direction. In this case, the barrel side groove 24 is a slit extending linearly from the rear end of the barrel body 22 along the axial direction da. However, this is not limited to this, and the barrel side groove 24 may be a groove formed on the inner surface of the barrel body 22 and not penetrating the barrel body 22 in the radial direction. A slide protrusion 59 of the holding member 50 is arranged in the barrel side groove 24. The operation of the slide protrusion 59 will be described later.

[0028] The tip member 26 is a member that forms the tip portion of the mechanical pencil 10. The tip member 26 has a generally conical shape, and its outer diameter decreases toward the front. The rear end of the tip member 26 is attached to the front end of the barrel body 22, thereby connecting the tip member 26 to the barrel body 22. As an example, the tip member 26 is connected to the barrel body 22 by screwing a female thread portion formed on the inner periphery of the rear end of the tip member 26 into a male thread portion formed on the outer periphery of the front end of the barrel body 22.

[0029] The payout mechanism 30 is a mechanism that pays out a writing lead 80 made of graphite or the like forward. The payout mechanism 30 of this embodiment includes a lead housing 40, a chuck 32, a resilient member 34, a fastener 36, and a lead holder 38. The lead housing 40 is a member that houses the writing lead 80. The lead housing 40 is disposed in the barrel 20. The lead housing 40 has a cylindrical (pipe) shape as a whole. The lead housing 40 also has a function of transmitting a pressing force received from the operating body 60 via the holding member 50 to the chuck 32. The lead housing 40 is formed of, for example, resin. The inner diameter of the rear end 42 of the lead housing 40 is larger than the inner diameter of the main body of the lead housing 40. The front end 51 of the holding member 50 is inserted into the rear end 42, whereby the holding member 50 is fixed to the lead housing 40.

[0030] A locking protrusion 44 is formed on the inner surface of the rear end 42 near the rear end. The locking protrusion 44 protrudes from the inner surface of the rear end 42 toward the inside in the radial direction. When the holding member 50 is attached to the lead accommodating part 40, the locking protrusion 44 is locked in the locking recess 52 of the holding member 50. This prevents the holding member 50 from being removed from the lead accommodating part 40 when the holding member 50 is pulled backward with a relatively small force in a state where the holding member 50 is attached to the lead accommodating part 40. The rear end 42 may have a plurality of locking protrusions 44. The plurality of locking protrusions 44 may be arranged at equal angular pitches with respect to each other in the circumferential direction dc. In this embodiment, three locking protrusions 44 are provided on the inner surface of the rear end 42. The three locking protrusions 44 are arranged at an angular pitch of 120 degrees with respect to each other.

[0031] The chuck 32 is a member that grips the writing lead 80. The chuck 32 is capable of moving in the front-to-rear direction together with the lead accommodating portion 40. In the example shown in FIG. 2, the rear end of the chuck 32 is inserted into the front end of the lead accommodating portion 40, thereby fixing the chuck 32 to the lead accommodating portion 40.

[0032] A resilient member 34 is disposed in front of the lead housing 40. The resilient member 34 is, for example, a coil spring. The resilient member 34 is disposed in a compressed state between a step provided on the outer surface of the front end of the lead housing 40 and a step provided on the inner surface of the front part of the barrel 20 (barrel body 22). The fastener 36 is an annular part located radially outward from the front part of the chuck 32. The rear end of the fastener 36 abuts on a step provided on the inner surface of the front part of the barrel 20 (barrel body 22), thereby restricting the rearward movement of the fastener 36. The lead holder 38 is disposed in front of the chuck 32 and is a member that abuts on the outer surface of the writing lead 80 to hold the writing lead 80. The lead holder 38 is formed of an elastic member such as resin or rubber, and prevents the writing lead 80 from moving in the axial direction da when the chuck 32 is not gripping the writing lead 80.

[0033] The attachment 15 is, for example, a member that changes handwriting. In particular, the attachment 15 may be a member that changes the writing surface by contacting the writing surface such as paper. The attachment 15 may be, for example, an eraser that rubs and removes handwriting made by the writing core 80. The attachment 15 may also be a friction body that changes the color of handwriting by frictional heat generated when the handwriting made by the thermochromic writing core 80 is rubbed. In this case, the handwriting may change from a first color to a second color different from the first color by frictional heat, or may change from colored to colorless by frictional heat. In the example shown in FIG. 2 and FIG. 3, the attachment 15 is fixed to the holding member 50 by being pressed into the rear end of the holding member 50. The attachment 15 may be configured to be detachable from the holding member 50. In this case, when the attachment 15 is worn or damaged, the attachment 15 can be replaced.

[0034] FIG. 4 is a diagram showing a part of the lead accommodating section 40 and the holding member 50. The holding member 50 is a member that holds the attachment 15. The holding member 50 is attached to the lead accommodating section 40. Specifically, the front end 51 of the holding member 50 is inserted into the rear end 42 of the lead accommodating section 40, thereby the holding member 50 is attached to the lead accommodating section 40. The holding member 50 also has a function of transmitting the pressing force received from the operating body 60 to the lead accommodating section 40. An engagement recess 52 is formed on the outer surface of the holding member 50. The engagement recess 52 is, for example, an annular recess extending along the circumferential direction dc. When the holding member 50 is attached to the lead accommodating section 40, the engagement protrusion 44 of the lead accommodating section 40 is engaged with the engagement recess 52.

[0035] The holding member 50 includes an engagement protrusion 53 and a slide protrusion 59. The engagement protrusion 53 is a protrusion that protrudes radially outward from the outer circumferential surface of the holding member 50. The engagement protrusion 53 is configured to be able to engage with an engagement groove 61. The rear end of the engagement protrusion 53 may be chamfered. In this case, when the operating body 60 is attached to the holding member 50, the engagement protrusion 53 and the guide portion 65 (first inclined surface 66, second inclined surface 67) of the operating body 60 can move smoothly relative to each other. In the example shown in FIG. 4, the rear end of the engagement protrusion 53 is chamfered so as to form an arc when viewed from the radial direction. A specific positional relationship between the engagement protrusion 53 and the engagement groove 61 when the operating body 60 is attached to and detached from the holding member 50 will be described later.

[0036] The slide protrusion 59 is a protrusion that protrudes radially outward from the outer circumferential surface of the holding member 50. In the example shown in FIG. 4, the slide protrusion 59 is disposed in front of the engagement protrusion 53. In particular, the slide protrusion 59 is disposed between the locking recess 52 and the engagement protrusion 53 along the axial direction da. The slide protrusion 59 is configured to be slidable in the axial direction da within the barrel side groove 24 of the barrel 20. As a result, when the holding member 50 is attached to the lead accommodating portion 40, the holding member 50 is movable in the axial direction da relative to the barrel 20 and cannot rotate around the central axis A.

[0037] 5A and 5B are longitudinal cross-sectional views of the operating body 60. FIG. 5B is a cross-sectional view of the same section as FIG. 5A, seen from the opposite side to FIG. 5A. The operating body 60 is a member operated by the user when advancing the writing lead 80. The operating body 60 is attached to the holding member 50. Specifically, the rear end of the holding member 50 is inserted into the front end of the operating body 60, thereby attaching the operating body 60 to the holding member 50. The operating body 60 includes an engagement groove 61, a guide portion 65, and a rolling prevention portion 69. The engagement groove 61 and the guide portion 65 are provided on the inner surface of the operating body 60. The rolling prevention portion 69 is provided on the outer surface of the operating body 60.

[0038] The engagement groove 61 is a groove with which the engagement protrusion 53 engages when the operating body 60 is attached to the holding member 50. The engagement groove 61 is a groove formed on the inner surface of the operating body 60. The engagement groove 61 extends with a predetermined length along the circumferential direction dc. In particular, the engagement groove 61 extends parallel to the circumferential direction dc. The engagement groove 61 is configured so that the engagement protrusion 53 can move around the central axis A (circumferential direction dc) in an angular range of 20 degrees to 70 degrees. Preferably, the engagement groove 61 is configured so that the engagement protrusion 53 can move in an angular range of 30 degrees to 50 degrees. More preferably, the engagement groove 61 is configured so that the engagement groove 61 can move in an angular range of 36 degrees to 42 degrees. In this embodiment, the engagement groove 61 is a groove formed penetrating the operating body 60 in the radial direction. In this case, the engagement groove 61 is a slit extending along the circumferential direction dc. However, without being limited thereto, the engagement groove 61 may be a groove formed on the inner surface of the operating body 60 and not penetrating the operating body 60 in the radial direction. Furthermore, the engagement groove 61 is not limited to extending parallel to the circumferential direction dc. The engagement groove 61 may extend in a direction inclined with respect to both the circumferential direction dc and the axial direction da. When the operating body 60 is attached to the holding member 50, the engagement protrusion 53 of the holding member 50 is positioned within the engagement groove 61.

[0039] The operating body 60 has a guide portion 65. The guide portion 65 has a function of guiding the engagement protrusion 53 toward the engagement groove 61 when the operating body 60 is attached to the holding member 50. In this embodiment, the guide portion 65 includes a first inclined surface 66 and a second inclined surface 67. The first inclined surface 66 extends in a direction inclined with respect to both the axial direction da and the circumferential direction dc so as to move toward one side of the circumferential direction dc as it moves toward the rear. The second inclined surface 67 extends in a direction inclined with respect to both the axial direction da and the circumferential direction dc so as to move toward the other side of the circumferential direction dc as it moves toward the rear. The guide portion 65 (the first inclined surface 66 and the second inclined surface 67) comes into contact with the engagement protrusion 53 when the operating body 60 is attached to the holding member 50, and guides the engagement protrusion 53 toward the engagement groove 61.

[0040] The anti-rolling portion 69 has a function of preventing the mechanical pencil 10 from rolling when the mechanical pencil 10 is placed on the top surface of a desk, table, etc. The anti-rolling portion 69 protrudes radially outward from the outer surface of the operating body 60. When the mechanical pencil 10 is placed on the top surface of a desk, table, etc., if the mechanical pencil 10 rolls and the anti-rolling portion 69 comes into contact with the top surface of the desk, table, etc., the mechanical pencil 10 is prevented from rolling any further. In this embodiment, when the holding member 50 and the operating body 60 are attached to the lead housing portion 40, the anti-rolling portion 69 also functions as a clip.

[0041] In this embodiment, the slide protrusion 59 of the holding member 50 and the front end of the anti-rolling portion 69 overlap in the radial direction. In this case, when attaching the holding member 50 and the operating body 60 to the lead accommodating portion 40, the user can visually align the anti-rolling portion 69 and the barrel side groove 24 in the circumferential direction dc. In this state, the holding member 50 and the operating body 60 can be easily attached to the lead accommodating portion 40 by moving the holding member 50 and the operating body 60 forward toward the lead accommodating portion 40. In addition, since the slide protrusion 59 and the front end of the anti-rolling portion 69 overlap in the radial direction, the slide protrusion 59 can be prevented from being visually recognized by the user. In other words, the slide protrusion 59 can be hidden by the anti-rolling portion 69.

[0042] The mechanical pencil 10 of this embodiment includes a rotation regulating section 70. The rotation regulating section 70 has a function of regulating the rotation of the operating body 60 relative to the holding member 50 when the operating body 60 is attached to the holding member 50. In particular, the rotation regulating section 70 regulates the rotation of the operating body 60 relative to the holding member 50 when the engagement protrusion 53 is positioned at one end 62 of the engagement groove 61. The rotation regulating section 70 includes a regulating groove 68 provided in the operating body 60 and a regulating protrusion 57 provided in the holding member 50.

[0043] The restriction groove 68 is a groove formed on the inner surface of the operating body 60. The restriction groove 68 extends linearly from the front end of the operating body 60 along the axial direction da (see FIGS. 5B and 6C). In this embodiment, the restriction groove 68 is a groove formed penetrating the operating body 60 in the radial direction. In this case, the restriction groove 68 is a slit extending linearly from the front end of the operating body 60 along the axial direction da. However, the present invention is not limited to this, and the restriction groove 68 may be a groove formed on the inner surface of the operating body 60 and not penetrating the operating body 60 in the radial direction.

[0044] The holding member 50 has an elastically deforming portion 55. The elastically deforming portion 55 has a tongue-like shape surrounded by two slits that extend linearly and parallel to each other in the axial direction da, and one slit that extends in the circumferential direction dc and connects the front ends of the two slits. This allows the front end of the elastically deforming portion 55 to elastically deform in the radial direction. A restricting protrusion 57 is provided at the front end of the elastically deforming portion 55.

[0045] When the engagement protrusion 53 is located at one end 62 of the engagement groove 61, the restriction protrusion 57 is located in the restriction groove 68. At this time, when the operating body 60 is rotated around the central axis A relative to the holding member 50 with a relatively small force, the restriction protrusion 57 comes into contact with the restriction groove 68, and the rotation of the operating body 60 relative to the holding member 50 is restricted. On the other hand, when the operating body 60 is rotated around the central axis A relative to the holding member 50 with a relatively large force, the restriction protrusion 57 comes into contact with the restriction groove 68, and then the elastic deformation portion 55 elastically deforms toward the inside in the radial direction, and the restriction protrusion 57 comes out of the restriction groove 68 in the circumferential direction dc. In this case, the operating body 60 can further rotate relative to the holding member 50. That is, the rotation of the operating body 60 relative to the holding member 50 may or may not be restricted by the rotation restriction portion 70 depending on the magnitude of the force in the circumferential direction dc acting on the operating body 60.

[0046] In the mechanical pencil 10 described above, when the user presses the operating body 60 forward, the resilient member 34 is compressed, and the lead accommodating section 40 and the chuck 32 move forward together with the operating body 60 and the holding member 50 against the resilient force of the resilient member 34. When the chuck 32 is not pressed forward, the outer surface of the front part of the chuck 32 abuts against the fastener 36 from the inside. Therefore, the front part of the chuck 32 is prevented from opening radially outward. This allows the front part of the chuck 32 to grip the writing lead 80. When the chuck 32 moves forward together with the fastener 36, the writing lead 80 gripped by the chuck 32 moves forward. When the chuck 32 moves further forward, the fastener 36 abuts against the inner step of the tip member 26, and the front part of the chuck 32 moves forward relative to the fastener 36. This causes the front portion of the chuck 32 to open outward, releasing the writing lead 80 that was gripped by the front portion of the chuck 32. At this time, the writing lead 80 is held by the lead holder 38.

[0047] When the user releases the pressure on the operating body 60, the operating body 60, the holding member 50, the lead accommodating portion 40, and the chuck 32 move backward due to the elastic force of the elastic member 34. This causes the front portion of the chuck 32 to move toward the inside of the fastener 36 and come into contact with the fastener 36 to grip the writing lead 80. At this time, the writing lead 80 is held by the lead holder 38, so the writing lead 80 is prevented from moving backward.

[0048] By repeating the above steps, the writing core 80 is advanced forward, and the front end of the writing core 80 protrudes forward from the front end of the barrel 20 (tip member 26).

[0049] 6A to 8B, a method for removing the holding member 50 and the operating body 60 from the lead accommodating part 40 and a method for attaching the holding member 50 and the operating body 60 to the lead accommodating part 40 when refilling the writing lead 80 will be described. In this embodiment, when the operating body 60 moves backward relative to the lead accommodating part 40 while the engagement protrusion 53 is positioned at one end 62 of the engagement groove 61, the holding member 50 and the operating body 60 come off from the lead accommodating part 40 with the engagement protrusion 53 remaining engaged with the engagement groove 61.

[0050] FIG. 6A is an external view showing a part of the mechanical pencil 10 in a state where the holding member 50 and the operating body 60 are attached to the lead housing 40. FIG. 6B is a cross-sectional view corresponding to the VIB-VIB line in FIG. 6A. FIG. 6C is a view showing the positional relationship between the engagement protrusion 53 of the holding member 50 and the engagement groove 61 of the operating body 60 in a state where the holding member 50 and the operating body 60 are attached to the lead housing 40. Note that in FIG. 6A, FIG. 7A, FIG. 8A, FIG. 9B, and FIG. 11B, illustration of a part of the anti-rolling portion 69 is omitted. In FIG. 6B, FIG. 7B, FIG. 8B, FIG. 9B, FIG. 10B, FIG. 11B, and FIG. 12B, only the shaft barrel body 22 and the lead housing 40 are shown in cross section, and other parts are shown in external views. 6C, 9C, 11C, and 12C show the engagement protrusion 53 and the engagement groove 61 in a state where a part of the front side of the operating body 60 is cut open on a plane parallel to the central axis A and developed. Therefore, in FIG. 6C, 9C, 11C, and 12C, the right end and the left end of the operating body 60 are connected. FIG. 6C, 9C, 11C, and 12C show the holding member 50 and the operating body 60 as viewed from the outside in the radial direction. FIG. 7B is a cross-sectional view corresponding to the line VIIB-VIIB in FIG. 7A. FIG. 8B is a cross-sectional view corresponding to the line VIIIB-VIIIB in FIG. 8A. FIG. 9B is a cross-sectional view corresponding to the line IXB-IXB in FIG. 9A. FIG. 10B is a cross-sectional view corresponding to the line XB-XB in FIG. 10A. FIG. 11B is a cross-sectional view corresponding to the line XIB-XIB in FIG. 11A. FIG. 12B is a cross-sectional view corresponding to the line XIIB-XIIB in FIG. 12A.

[0051] As shown in Figures 6A and 6B, when the holding member 50 and the operating body 60 are attached to the lead accommodating section 40, the engagement protrusion 53 of the holding member 50 is located at one end 62 of the engagement groove 61 of the operating body 60 (see Figures 6B and 6C). The one end 62 of the engagement groove 61 is an end on one side of the engagement groove 61 in the circumferential direction dc. The other end 63 of the engagement groove 61 is an end on the other side of the engagement groove 61 in the circumferential direction dc. When the engagement protrusion 53 is located at the one end 62, the restriction protrusion 57 of the holding member 50 is located within the restriction groove 68 of the operating body 60.

[0052] When removing the holding member 50 and the operating body 60 from the lead housing 40, the user pulls the operating body 60 backward along the axial direction da. This causes the operating body 60 to move backward relative to the lead housing 40. At this time, the front wall of the engagement groove 61 comes into contact with the front end of the engagement protrusion 53. When the operating body 60 further moves backward, it is pushed by the front wall of the engagement groove 61, and the engagement protrusion 53 also moves backward (see Figures 7A and 7B). That is, the holding member 50 and the operating body 60 move backward together. At this time, the holding member 50 and the operating body 60 are removed together from the lead housing 40. When the operating body 60 further moves backward, the holding member 50 and the operating body 60 are removed together from the shaft tube 20 (see Figures 8A and 8B). In this state, the user can refill the lead housing 40 with the writing lead 80. Specifically, the writing lead 80 is inserted into the lead housing 40 via the rear end 42. After refilling the lead housing 40 with the writing lead 80, the holding member 50 and the operating body 60 are attached to the lead housing 40 again.

[0053] When attaching the holding member 50 and the operating body 60 to the lead housing 40, the user first aligns the slide protrusion 59 of the holding member 50 with the barrel side groove 24 of the barrel 20 in the circumferential direction dc (see Figs. 8A and 8B). In this embodiment, the slide protrusion 59 of the holding member 50 and the front end of the anti-rolling portion 69 overlap in the radial direction. Therefore, the user can easily align the slide protrusion 59 with the barrel side groove 24 by visually aligning the anti-rolling portion 69 with the barrel side groove 24 in the circumferential direction dc. In this state, when the holding member 50 and the operating body 60 are moved forward toward the lead housing 40, the holding member 50 and the operating body 60 are attached to the lead housing 40 as shown in Figs. 6A and 6B via the state shown in Figs. 7A and 7B.

[0054] 6A to 6C and 9A to 12C, a method for removing the operating body 60 from the holding member 50 and a method for attaching the operating body 60 to the holding member 50 when using the attachment 15 will be described. In this embodiment, when the operating body 60 moves backward with respect to the core accommodating section 40 while the engagement protrusion 53 is positioned at the other end 63 of the engagement groove 61, the engagement protrusion 53 comes out of the engagement groove 61 and the operating body 60 comes out of the holding member 50.

[0055] When removing the operating body 60 from the holding member 50, the user first rotates the operating body 60 toward one side of the circumferential direction dc relative to the holding member 50 in the state shown in Figs. 6A to 6C in which the holding member 50 and the operating body 60 are attached to the core housing 40. In this embodiment, the operating body 60 is rotated counterclockwise relative to the holding member 50 when viewed from behind. The engagement groove 61 extends with a predetermined length along the circumferential direction dc. In particular, the engagement groove 61 is configured so that the engagement protrusion 53 can move around the central axis A within an angular range of 20 degrees or more and 70 degrees or less. In this case, the operating body 60 rotates with respect to the holding member 50 within an angular range of 20 degrees or more and 70 degrees or less.

[0056] When the operating body 60 rotates toward one side in the circumferential direction dc relative to the holding member 50, the engaging protrusion 53 of the holding member 50 moves from one end 62 of the engaging groove 61 of the operating body 60 to the other end 63 (see Figs. 9B and 9C). At this time, by rotating the operating body 60 about the central axis A relative to the holding member 50 with a relatively large force, the elastic deformation portion 55 of the holding member 50 elastically deforms toward the inside in the radial direction, and the restricting protrusion 57 comes out of the restricting groove 68 in the circumferential direction dc.

[0057] In this state, the user pulls the operating body 60 backward along the axial direction da. As a result, the engagement protrusion 53 comes out forward from the engagement groove 61. Therefore, the operating body 60 is removed from the holding member 50. In this embodiment, when the operating body 60 rotates at an angle range of 20 degrees or more and 70 degrees or less with respect to the holding member 50 and then moves backward with respect to the lead accommodating section 40, the operating body 60 comes off the holding member 50. As a result, the attachment 15 is exposed. In this state, the user can use the attachment 15. If the attachment 15 is an eraser, the user can erase the handwriting made by the writing lead 80 by rubbing it.

[0058] When attaching the operating body 60 to the holding member 50, simply moving the operating body 60 forward toward the holding member 50 does not necessarily position the engagement protrusion 53 of the holding member 50 at the other end 63 of the engagement groove 61. In many cases, simply moving the operating body 60 forward toward the holding member 50 causes the engagement protrusion 53 to come into contact with any part of the guide portion 65 of the operating body 60. The guide portion 65 includes a first inclined surface 66 and a second inclined surface 67. Therefore, simply moving the operating body 60 forward toward the holding member 50 causes the engagement protrusion 53 to come into contact with the first inclined surface 66 or the second inclined surface 67 in many cases.

[0059] 11A to 11C show an example in which the engagement protrusion 53 comes into contact with the first inclined surface 66 when the operating body 60 is moved forward toward the holding member 50. Also, FIGS. 12A to 12C show an example in which the engagement protrusion 53 comes into contact with the second inclined surface 67 when the operating body 60 is moved forward toward the holding member 50.

[0060] In the example shown in FIG. 11C, when the operating body 60 is further moved forward toward the holding member 50, the engagement protrusion 53 is guided by the first inclined surface 66 and moves toward the other end 63 of the engagement groove 61. At this time, the operating body 60 rotates toward the other side of the circumferential direction dc. In the example shown in FIG. 12C, when the operating body 60 is further moved forward toward the holding member 50, the engagement protrusion 53 is guided by the second inclined surface 67 and moves toward the other end 63 of the engagement groove 61. At this time, the operating body 60 rotates toward one side of the circumferential direction dc. As a result, the engagement protrusion 53 is positioned at the other end 63 of the engagement groove 61. Depending on the angle of the operating body 60 with respect to the holding member 50, the engagement protrusion 53 may be positioned at the other end 63 of the engagement groove 61 without contacting the guide portion 65 (the first inclined surface 66 and the second inclined surface 67). At this time, the elastic deformation portion 55 of the holding member 50 elastically deforms radially inward, and the restricting protrusion 57 comes into contact with the inner surface of the operating body 60.

[0061] Thereafter, when the user rotates the operating body 60 toward the other side in the circumferential direction dc, the engaging protrusion 53 is positioned at one end 62 of the engaging groove 61. At this time, the restricting protrusion 57 of the holding member 50 is positioned within the restricting groove 68 of the operating body 60 (see FIGS. 6A to 6C).

[0062] The mechanical pencil 10 of this embodiment comprises a lead accommodating section 40 capable of accommodating a writing lead 80, a retaining member 50 that is attached to the lead accommodating section 40 and holds the accessory 15, and an operating body 60 attached to the retaining member 50, the operating body 60 having an engagement groove 61 and the retaining member 50 having an engagement protrusion 53 that can engage with the engagement groove 61, and when the operating body 60 moves rearward relative to the lead accommodating section 40 while the engagement protrusion 53 is positioned at one end 62 of the engagement groove 61, the retaining member 50 and the operating body 60 disengage from the lead accommodating section 40 with the engagement protrusion 53 remaining engaged with the engagement groove 61, and when the operating body 60 moves rearward relative to the lead accommodating section 40 while the engagement protrusion 53 is positioned at the other end 63 of the engagement groove 61, the engagement protrusion 53 disengages from the engagement groove 61 and the operating body 60 disengages from the retaining member 50.

[0063] In the mechanical pencil 10 of this embodiment, the engagement groove 61 extends in the circumferential direction dc.

[0064] According to such a mechanical pencil 10, since the engagement groove 61 has a predetermined length along the circumferential direction dc, the engagement protrusion 53 can be moved from one end 62 to the other end 63 by rotating the operating body 60 by a predetermined angle with respect to the holding member 50. Then, by pulling the operating body 60 backward in this state, the operating body 60 can be removed from the holding member 50. In other words, it becomes possible to remove the operating body 60 with a single rotation operation without rotating the operating body 60 multiple times.

[0065] In the mechanical pencil 10 of this embodiment, the engagement groove 61 is configured so that the engagement protrusion 53 can move around the central axis A within an angular range of 20 degrees or more and 70 degrees or less.

[0066] The mechanical pencil 10 of this embodiment comprises a lead accommodating section 40 capable of accommodating a writing lead 80, a holding member 50 that is attached to the lead accommodating section 40 and holds the accessory 15, and an operating body 60 that is attached to the holding member 50. When the operating body 60 moves backward relative to the lead accommodating section 40 without rotating relative to the holding member 50, the holding member 50 and the operating body 60 come off the lead accommodating section 40, and when the operating body 60 moves backward relative to the lead accommodating section 40 after rotating through an angle range of 20 degrees or more and 70 degrees or less relative to the holding member 50, the operating body 60 comes off the holding member 50.

[0067] According to such a mechanical pencil 10, the operating body 60 can be removed simply by rotating the operating body 60 within an angle range of 20 degrees to 70 degrees with respect to the holding member 50 and then moving it backward. This makes it even easier to remove the operating body 60 with a single rotation operation.

[0068] In the mechanical pencil 10 of this embodiment, the operating body 60 has a guide portion 65 that guides the engagement projection 53 toward the engagement groove 61 when the operating body 60 is attached to the holding member 50.

[0069] In the mechanical pencil 10 of this embodiment, the guide portion 65 includes a first inclined surface 66 that extends in a direction inclined with respect to both the axial direction da and the circumferential direction dc so as to move toward one side of the circumferential direction dc toward the rear, and a second inclined surface 67 that extends in a direction inclined with respect to both the axial direction da and the circumferential direction dc so as to move toward the other side of the circumferential direction dc toward the rear.

[0070] According to such a mechanical pencil 10, even if the engagement protrusion 53 and the other end 63 of the engagement groove 61 are not aligned in the circumferential direction dc, the engagement protrusion 53 is guided by the guide portion 65 and moves toward the other end 63 of the engagement groove 61. Therefore, the operation body 60 can be easily attached to the holding member 50.

[0071] The mechanical pencil 10 of this embodiment has a rotation restricting portion 70 that restricts the rotation of the operating body 60 relative to the holding member 50 when the engaging projection 53 is positioned in one end 62 of the engaging groove 61 .

[0072] In the mechanical pencil 10 of this embodiment, the rotation regulating portion 70 includes a regulating groove 68 provided in the operating body 60 and a regulating protrusion 57 provided in the holding member 50.

[0073] In the mechanical pencil 10 of this embodiment, the holding member 50 has an elastically deformable portion 55 including a restricting protrusion 57.

[0074] According to such a mechanical pencil 10, in a state in which the operating body 60 is attached to the holding member 50, the operating body 60 is prevented from rotating in the circumferential direction dc with respect to the holding member 50 with a relatively small force. Therefore, it is possible to prevent the operating body 60 from rotating in the circumferential direction dc with respect to the holding member 50 against the user's intention and the operating body 60 from coming off the holding member 50.

[0075] The mechanical pencil 10 of this embodiment has a barrel 20 that houses the lead accommodating section 40, the barrel 20 has a barrel side groove 24 extending in the axial direction da, and the holding member 50 has a slide protrusion 59 configured to be slidable in the axial direction da within the barrel side groove 24.

[0076] With such a mechanical pencil 10, when the holding member 50 is attached to the lead housing 40, the holding member 50 is movable in the axial direction da relative to the barrel 20 but is unable to rotate around the central axis A. Therefore, while allowing the advancing operation for advancing the writing lead 80, when the user rotates the operating body 60 in the circumferential direction dc, the holding member 50 together with the operating body 60 can be prevented from rotating in the circumferential direction dc.

[0077] In the mechanical pencil 10 of this embodiment, the operating body 60 has a rolling prevention portion 69 that protrudes radially outward.

[0078] According to such a mechanical pencil 10, when the mechanical pencil 10 is placed on the top surface of a desk, a table, or the like, the mechanical pencil 10 can be prevented from rolling. [Explanation of symbols]

[0079] 10. Mechanical Pencil 15 Accessories 20 shaft cylinder 22. Body of barrel 24. Axle barrel groove 26 Tip member 30 Payout mechanism 32 Chuck 34 Elastic members 36 Fasteners 38 Lead holder 40 core housing 42 Rear end 44 Locking protrusion 50 Retaining member 51 Front end 52 Locking recess 53 Engagement protrusion 55 Elastically deformable part 57 Regulating protrusion 59 Slide protrusion 60 Control unit 61 Engagement groove 62 One end 63 Other end 65 Guide part 66 First Slope 67 Second Slope 68 Regulating Groove 69 Anti-rolling part 70 Rotation control part 80 writing lead A Center axis da Axial direction dc circumferential direction

Claims

1. A lead housing portion capable of housing a writing lead; A holding member that is attached to the core housing and holds an accessory; An operation body attached to the holding member, The operation body has an engagement groove, The holding member has an engagement protrusion that can be engaged with the engagement groove, When the engagement protrusion is located at one end of the engagement groove, if the operation body moves backward with respect to the lead accommodating portion, the holding member and the operation body are disengaged from the lead accommodating portion while the engagement protrusion remains engaged with the engagement groove, When the operating body moves rearward relative to the lead accommodating portion while the engagement protrusion is positioned at the other end of the engagement groove, the engagement protrusion disengages from the engagement groove and the operating body disengages from the holding member.

2. The mechanical pencil according to claim 1 , wherein the engagement groove extends in a circumferential direction.

3. The mechanical pencil according to claim 1 , wherein the engagement groove is configured so that the engagement protrusion can move within an angular range of 20 degrees or more and 70 degrees or less around a central axis.

4. The mechanical pencil according to claim 1 , wherein the operating body has a guide portion that guides the engagement projection toward the engagement groove when the operating body is attached to the holding member.

5. 5. The mechanical pencil according to claim 4, wherein the guide portion includes a first inclined surface 66 extending in a direction inclined with respect to both the axial direction and the circumferential direction so as to move toward one side in the circumferential direction toward the rear, and a second inclined surface extending in a direction inclined with respect to both the axial direction and the circumferential direction so as to move toward the other side in the circumferential direction toward the rear.

6. The mechanical pencil according to claim 1 , further comprising a rotation restricting portion that restricts rotation of the operating body relative to the holding member when the engaging projection is positioned at the one end of the engaging groove.

7. The mechanical pencil according to claim 6 , wherein the rotation restricting portion includes a restricting groove provided in the operating body and a restricting protrusion provided in the holding member.

8. The mechanical pencil according to claim 7 , wherein the holding member has an elastically deformable portion including the restricting protrusion.

9. A barrel that accommodates the lead accommodating portion, The barrel has a barrel side groove extending in the axial direction, The mechanical pencil according to claim 1 , wherein the holding member has a slide protrusion configured to be axially slidable within the barrel side groove.

10. The mechanical pencil according to claim 1 , wherein the operating body has a rolling prevention portion protruding radially outward.

11. A lead housing portion capable of housing a writing lead; A holding member that is attached to the core housing and holds an accessory; An operation body attached to the holding member, When the operating body moves backward with respect to the lead accommodating portion without rotating with respect to the holding member, the holding member and the operating body are disengaged from the lead accommodating portion, The mechanical pencil, when the operating body moves backward with respect to the lead housing section after rotating through an angle range of 20 degrees or more and 70 degrees or less with respect to the holding member, the operating body comes off the holding member.

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