Ballpoint pen

Abstract

This ballpoint pen comprises: a knock spring that is interposed between a shaft cylinder and a refill; a rotor that has a rear end surface with cams formed thereon and a pressing rod that protrudes rearward; a knock button having an internal space into which the pressing rod is inserted; an inner peripheral cam formed on an inner surface near the rear end of the shaft cylinder; a plurality of engagement cams that are formed on the rear end surface of the rotor and that mesh with the inner peripheral cam; and an inclined surface that is the front-end surface of the rotor and is inclined rearward. The ballpoint pen is formed such that, in a state in which the engagement cams are engaged with the inner peripheral cam after the rotor is pressed by the knock button, the refill is urged backward by the knock spring and the inclined surface is pressed backward by the rear end of the refill so that the rotor is inclined, with respect to the axial center, toward the side of the position of the inclined surface closest to the rear, and so that the pressing rod presses the inner peripheral surface of the knock button to fix the knock button with respect to the shaft cylinder.

Description

ballpoint pen

[0001] The present disclosure relates to a knock-type ballpoint pen.

[0002] With regard to so-called knock-type ballpoint pens, in which the tip of the built-in refill is inserted or removed from the tip of the barrel by pressing a knock button protruding from the rear end of the barrel, technologies such as those described in JP 2023-70970 A, JP 2009-34879 A, ​​JP 2015-3443 A, JP 2016-37011 A, and JP 2016-107615 A ​​are disclosed.

[0003] In these prior art pens, a cam is formed on the rotor that is pressed by the knock button. The knock button and the rotor are urged backward by a knock spring housed in the barrel. When the knock button is pressed against the urging force of the knock rod, the rotor moves forward, and the cam of this rotor engages with a cam formed on the inner periphery of the barrel. At this time, the knock spring urges the rotor backward, maintaining this engaged state. In this state, the tip of the refill protrudes from the tip of the barrel, maintaining the writing position.

[0004] When the knock button is pressed again from this state, the engagement between the rotor cam and the barrel cam is released. The rotor is then biased backward by the knock spring and moves backward. As a result, the tip of the refill is retracted into the barrel.

[0005] In a knock-type ballpoint pen, when the knock button is pressed down and in the writing state, the knock button and the rotor are not physically engaged, and the knock button is usually free. Therefore, the knock button can vibrate along with the vibrations that occur during writing. The ballpoint pen of the present disclosure aims to prevent vibration of the knock button when pressed down during writing.

[0006] (1) First Aspect A ballpoint pen according to a first aspect of the present disclosure comprises a barrel, a refill housed in the barrel and having a tip that protrudes and retracts from the barrel in response to a knock operation, a knock spring interposed between the barrel and the refill and urging the refill rearward, a rotor having a cam formed on its rear end surface and a cam portion that is generally cylindrical, and a push rod that protrudes rearward from the cam portion and is rod-shaped with a smaller diameter, and that abuts against the rear end of the refill, a knock button that protrudes partially from the rear end of the barrel while abutting against the push rod inserted into the internal space, and abutting against the rear end of the cam portion, an inner cam formed on the inner surface near the rear end of the barrel, a knock cam formed on the front end surface of the knock button, a rotating cam formed on the rear end surface of the rotor and engaging with the knock cam, a plurality of engagement cams formed on the outer periphery of the rotating cam and engaging with the inner cam, and a rearward inclined surface that is the front end surface of the rotor.

[0007] The ballpoint pen of an embodiment of the present disclosure is further configured so that, when the rotor is pressed by the knock button and the engagement cam is engaged with the inner cam, the refill is urged rearward by the knock spring, and the inclined surface is pressed rearward by the rear end of the refill, causing the rotor to incline toward the side of the inclined surface closest to the rear relative to the axis, and the pressure rod presses the inner surface of the knock button to fix the knock button to the barrel.

[0008] When the knock button is pressed against the force of the knock spring, the knock cam of the knock button engages with the rotating cam of the rotor, and the knock button pushes the rotor forward. As the rotor is pushed forward, the rotor pushes the refill forward. Then, the engagement cam of the rotor engages with the inner cam of the barrel, keeping the tip of the refill protruding from the barrel and entering the writing state.

[0009] In this state, the refill is urged backward by the knock spring. The rear end of the refill then abuts against and presses against the inclined surface of the rotor. This causes the rotor to tilt toward the rearmost side of the inclined surface relative to the axis. As the rotor tilts, the push rod presses against the inner surface of the knock button, pushing the knock button toward the pressed side. The knock button is clamped between the push rod and the inner surface of the barrel, preventing it from moving. This prevents the knock button from vibrating when writing.

[0010] (2) Second aspect A ballpoint pen according to a second aspect of the present disclosure has, in addition to the configuration of the first aspect, the multiple engaging cams are provided with an inclined cam whose position at which it engages with the inner cam is closer to the front than the others and which is located on the side of the inclined surface closest to the front, and a fulcrum cam which faces the inclined cam across the axis and whose position at which it engages with the inner cam is closer to the rear than the others and which is located on the side of the inclined surface closest to the rear, and it is desirable that the rotor tilts toward the fulcrum cam when the inclined cam engages with the inner cam.

[0011] As described in the first embodiment above, in the writing state, the rear end of the refill abuts against and presses against the inclined surface of the rotor. This causes the rotor to tilt toward the rearmost side of the inclined surface relative to the axis. At this time, of the engagement cams engaged with the inner circumferential cam of the barrel, the fulcrum cam located furthest to the rear and the inclined cam located furthest to the front simultaneously engage with the inner circumferential cam, causing the rotor to tilt toward the fulcrum cam.

[0012] (3) Third Aspect A ballpoint pen according to a third aspect of the present disclosure has, in addition to the configuration of the second aspect, a forward protrusion that protrudes forward on the side of the inclined surface where the fulcrum cam is provided.

[0013] As described in the first embodiment above, in the writing state, the rear end of the refill abuts against and presses against the inclined surface of the rotor. At this time, the rear end of the refill abuts against this forward protrusion, which makes it easier for the rear end of the refill to press backward against the position of the inclined cam located opposite the forward protrusion. As a result, the rotor is more likely to tilt toward the fulcrum cam.

[0014] Since the ballpoint pen of the present disclosure is configured as described above, when writing, it is possible to prevent vibration of the knock button that is pressed down by pressing the knock button with the tilt of the rotor.

[0015] FIG. 1 is a front view of a ballpoint pen of a first embodiment. FIG. 1B is a side view of the ballpoint pen of FIG. 1A. FIG. 1C is a cross-sectional view taken along II-I of FIG. 1A. FIG. 1D is a front view of an inner shaft used in the ballpoint pen of FIG. 1A. FIG. 2E is a side view of the inner shaft of FIG. 2A. FIG. 2F is a plan view of the inner shaft of FIG. 2A. FIG. 2G is a bottom view of the inner shaft of FIG. 2A. FIG. 2H is a cross-sectional view taken along IIa-IIa of FIG. 2A. FIG. 2H is a cross-sectional view taken along IIb-IIb of FIG. 2E. FIG. 1E is a front view of a rotor used in the ballpoint pen of FIG. 1A. FIG. 3A is a side view of the rotor of FIG. 3A. FIG. 3A is a front oblique view of the rotor of FIG. 3A. FIG. 3A is a rear oblique view of the rotor of FIG. 3A. FIG. 3A is a bottom view of the rotor of FIG. 3A. FIG. 3A is a cross-sectional view taken along III-III of FIG. 3A. FIG. 1F is a front view of a knock button used in the ballpoint pen of FIG. 1A. FIG. 4A is a side view of the knock button of FIG. 4A. FIG. 4A is a rear oblique view of the knock button of FIG. 4A. FIG. 4A is a bottom view of the knock button of FIG. 4A. FIG. 4A is a cross-sectional view taken along IV-IV of FIG. 4A. FIG. 1C shows an enlarged view of the rear end portion. 1 is a front view of a ballpoint pen in a writing state; 2 is a perspective view of the ballpoint pen of FIG. 6A; 3 is a cross-sectional view taken along line VI-VI of FIG. 6A; 4 is an enlarged view of the rear end portion of FIG. 6C; 5 is a front view of a ballpoint pen of a second embodiment; 6 is a side view of the ballpoint pen of FIG. 8A; 7 is a cross-sectional view taken along line VIII-VIII of FIG. 8A; 8 is a front view of a rotor used in the ballpoint pen of FIG. 8A; 9 is a side view of the rotor of FIG. 9A; 10 is a rear perspective view of the rotor of FIG. 9A; 11 is a front perspective view of the rotor of FIG. 9A; 12 is a bottom view of the rotor of FIG. 9A; 13 is a cross-sectional view taken along line IX-IX of FIG. 9A; 14 is an enlarged view of the rear end portion of FIG. 8C; 15 is a front view of the ballpoint pen of FIG. 8A with the knock button pressed; 16 is a side view of the ballpoint pen of FIG. 11A; 17 is a cross-sectional view taken along line XI-XI of FIG. 11A; 18 is an enlarged view of the rear end portion of FIG. 11C.

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that symbols commonly used in the drawings indicate common configurations or components even if not mentioned in the description of each drawing. In the following description, the side of the ballpoint pen where the ballpoint pen tip is located will be referred to as the "front end," and the opposite side, i.e., the side where the knock button is located, will be referred to as the "rear end." At any position on the ballpoint pen, the direction of the front end will be referred to as the "forward" and the direction of the rear end will be referred to as the "rear."

[0017] (1) First Embodiment (1-1) Overall Configuration of Ballpoint Pen 10 The overall configuration of the ballpoint pen 10 of the first embodiment will be described with reference to Figures 1A to 1C. Figure 1A is a front view of the ballpoint pen 10, Figure 1B is a side view of the ballpoint pen 10 of Figure 1A, and Figure 1C is a cross-sectional view taken along line II of Figure 1A. Figures 1A to 1C show the ballpoint pen 10 in a non-writing state.

[0018] The ballpoint pen 10 of this embodiment has an exterior appearance in which a knock button 70 protrudes from the rear end of a barrel 15 equipped with a clip 33. The barrel 15 is a generally cylindrical member and is composed of an outer barrel 20 that houses a refill 50 (FIG. 1C), an inner barrel 30 attached to the rear end of the outer barrel 20, and a front barrel 40 attached to the front end of the outer barrel 20. The outer barrel 20, inner barrel 30, and front barrel are molded from hard resin. A grip 21 made of an elastic resin material such as elastomer is attached to the outer peripheral surface of the front end of the outer barrel 20. The front end of the outer barrel 20 has a reduced outer diameter and is formed with a male thread 22 (FIG. 1C) with a thread cut on the outer peripheral surface.

[0019] Lead barrel 40 is composed of large-diameter section 41 located at the rear and having a relatively large outer diameter, and tapered section 43 located at the front, whose outer diameter gradually decreases toward the tip. The inner circumferential surface of large-diameter section 41 is formed with a female-threaded section 42 ( FIG. 1C ). A tip opening 46 through which ballpoint pen tip 53 ( FIG. 1C ) appears is provided at the tip of lead barrel 40. Lead barrel 40 is attached to outer barrel 20 by threading female-threaded section 42 into male-threaded section 22. As shown in FIG. 1C , inner barrel 30 is composed of exposed section 31 exposed to the outside, insertion section 32 inserted into outer barrel 20, and clip 33 formed on the front side of exposed section 31 and extending forward. A packing 12 made of an elastic resin material is interposed between exposed section 31 of inner barrel 30 and the rear end of the outer circumference of outer barrel 20. Details of the structure of inner barrel 30 will be described later.

[0020] As shown in FIG. 1C , the barrel 15 accommodates a refill 50. The refill 50 is composed of a tubular ink reservoir 51 made of a relatively soft resin, a coupling 52 attached to the tip of the ink reservoir 51, and a ballpoint pen tip 53 attached to the tip of the coupling 52. The ink reservoir 51 accommodates ink 51A, and further accommodates a follower 51B behind the ink 51A. The ballpoint pen tip 53 has a structure in which a metal writing ball 53B is held at the tip of a metal, approximately cylindrical holder 53A. The coupling 52 is a member that connects the ink reservoir 51 and the ballpoint pen tip 53, and is composed of a relatively large-diameter rear connection portion 52A into which the tip of the ink reservoir 51 is press-fitted, and a relatively small-diameter front connection portion 52B into which the rear end of the ballpoint pen tip 53 is press-fitted.

[0021] As shown in Figure 1C, a rotor 60 is attached inside the exposed portion 31 of the inner shaft 30. The leading end of the rotor 60 abuts against the rear end of the refill 50. The rear end portion of the rotor 60 is inserted into and abuts against the internal space of the knock button 70. The structures of the rotor 60 and the knock button 70 will be described in detail below.

[0022] 1C, a knock spring 11 is interposed between the step between rear connecting portion 52A and front connecting portion 52B of joint 52 and a step formed inside tapered portion 43 of front barrel 40. This knock spring 11 constantly urges refill 50, rotor 60, and knock button 70 rearward.

[0023] (1-2) Inner barrel 30 The structure of the inner barrel 30 used in the ballpoint pen 10 of this embodiment will be described with reference to Figures 2A to 2F. Figure 2A is a front view of the inner barrel 30, Figure 2B is a side view of the inner barrel 30, Figure 2C is a plan view of the inner barrel 30, Figure 2D is a bottom view of the inner barrel 30, Figure 2E is a cross-sectional view taken along IIa-IIa in Figure 2A, and Figure 2F is a cross-sectional view taken along IIb-IIb in Figure 2E.

[0024] The inner shaft 30 is composed of an exposed portion 31 exposed to the outside, an insertion portion 32 inserted into the outer shaft 20, and a clip 33 formed on the front side of the exposed portion 31 and extending forward. The exposed portion 31 has a generally cylindrical shape whose outer diameter tapers slightly toward the rear. The tip side of the exposed portion 31 is inclined (FIG. 2B) so that it is longer on the front side and shorter on the rear side to match the shape of the rear end side of the outer shaft 20 to which it is attached (see FIG. 1B). The rear end surface of the exposed portion 31 is also inclined in a similar manner. Furthermore, a rear end opening 38 through which the knock button 70 (FIGS. 1A to 1C) passes is formed at the rear end of the exposed portion 31 (FIGS. 2A, 2C, and 2E). The insertion portion 32 is generally cylindrical and has a smaller diameter than the exposed portion 31. The tip of the insertion portion 32 is beveled to match the inclination of the tip side of the exposed portion 31.

[0025] As shown in Figures 2E and 2F, eight guide ridges 34 extending in the axial direction are evenly spaced on the inner circumferential surface of the exposed portion 31. Four relatively deep first guide grooves 36 and four relatively shallow second guide grooves 37 are alternately and evenly spaced between the guide ridges 34 (Figure 2F). An inner circumferential cam 35 is formed at the tip of each guide ridge 34 (Figures 2D and 2E) with which an engagement cam 64 (Figure 3A) of the rotor 60, which will be described later, engages. In addition, the inner diameter of the inner circumferential surface of the inner shaft 30 is slightly smaller near the rear end, forming a rear-end step 39 (Figure 2E).

[0026] (1-3) Rotor 60 The structure of the rotor 60 used in the ballpoint pen 10 of this embodiment will be described with reference to Figures 3A to 3G. Figure 3A is a front view of the rotor 60, Figure 3B is a side view of the rotor 60, Figure 3C is a front perspective view of the rotor 60, Figure 3D is a rear perspective view of the rotor 60, Figure 3E is a plan view of the rotor 60, Figure 3F is a bottom view of the rotor 60, and Figure 3G is a cross-sectional view taken along the line III-III in Figure 3A.

[0027] The rotor 60 is composed of a generally cylindrical cam portion 61 on which a cam is formed, and a columnar pressure rod 62 that has a smaller diameter than the cam portion 61 and protrudes to the tip. A sawtooth rotating cam 63 with eight alternating peaks and eight valleys is formed on the tip surface of the cam portion 61 (FIG. 3D). Meanwhile, the rear edge of the cam portion 61 forms a flange 68 with an increased outer diameter. Four inner peripheral ribs 65 extending in the axial direction are equally spaced on the inner peripheral surface of the cam portion 61 (FIGS. 3C, 3F, and 3G).

[0028] Four sliding ridges 67 extending in the axial direction are evenly spaced on the outer peripheral surface of the cam portion 61. An engaging cam 64 is formed at the tip of each sliding ridge 67 as an inclined surface whose height increases from right to left when viewed from the front. The sliding ridges 67 are positioned so that the inclination of the engaging cam 64 matches the inclination of the rotating cam 63 (FIGS. 3A, 3B, and 3D). The outer peripheral surface of the sliding ridges 67 matches the outer peripheral surface of the flange 68 (FIGS. 3A to 3D and 3E). The sliding ridges 67 are recessed into the first guide groove 36 (FIG. 2F) of the inner shaft 30 and slide back and forth along the first guide groove 36.

[0029] Of the four engagement cams 64, one has a cam surface located closer to the tip than the others, and is referred to as the inclined cam 64A (FIGS. 3A, 3B, 3D, and 3E). Of the four engagement cams 64, the other has a cam surface located closer to the rear end than the others, and is referred to as the fulcrum cam 64B (FIGS. 3B, 3D, and 3E). The cam surface of the fulcrum cam 64B coincides with the cam surface of the rotating cam 63 (FIGS. 3B and 3E). The engagement cams 64 other than the fulcrum cam 64B and the cam surfaces of the engagement cams 64 are located closer to the tip than the cam surface of the rotating cam 63 (FIGS. 3A, 3B, and 3D).

[0030] The tip end surface of the rotor 60 forms an inclined surface 66 that slopes backward (FIGS. 3B, 3C, 3F, and 3G). Specifically, the side of the inclined surface 66 closest to the front corresponds to the side where the inclined cam 64A is located. Also, the side of the inclined surface 66 closest to the rear corresponds to the side where the fulcrum cam 64B is located (FIGS. 3B and 3G).

[0031] (1-4) Knock Button The structure of the knock button 70 used in the ballpoint pen 10 of this embodiment will be described with reference to Figures 4A to 4F. Figure 4A is a front view of the knock button 70, Figure 4B is a side view of the knock button 70, Figure 4C is a rear perspective view of the knock button 70, Figure 4D is a plan view of the knock button 70, Figure 4E is a bottom view of the knock button 70, and Figure 4F is a cross-sectional view taken along line IV-IV in Figure 4A.

[0032] The knock button 70 is composed of a generally cylindrical cam barrel portion 71 located in the front and a generally cylindrical protrusion portion 72 located in the rear, which is slightly tapered at the rear. The cam barrel portion 71 slides back and forth inside the exposed portion 31 (Fig. 2E) of the inner barrel 30. The protrusion portion 72 protrudes from the rear end of the barrel 15 when the pen is not in writing (Figs. 1A to 1C). Shallow grooves 75 are formed on the front and back of the protrusion portion 72 (Figs. 4A, 4D, and 4F).

[0033] A sawtooth knock cam 74 with eight alternating peaks and eight valleys is formed on the tip end surface of the cam barrel portion 71 ( FIGS. 4A to 4C , 4E , and 4F ). The knock cam 74 is formed so that the peaks and valleys mesh with the rotating cam 63 ( FIGS. 3D and 3E ) of the rotor 60. Eight guide protrusions 73 are also evenly spaced on the outer periphery of the cam barrel portion 71. Each guide protrusion 73 fits into either the first guide groove 36 or the second guide groove 37 ( FIG. 2F ) of the inner shaft 30 and slides back and forth along either the first guide groove 36 or the second guide groove 37.

[0034] (1-5) Non-Writing State In the non-writing state shown in FIG. 1C, the refill 50 is biased rearward by the knock spring 11, which in turn presses the rotor 60 and knock button 70 rearward. As shown in FIG. 5, which is an enlarged view of the rear end of FIG. 1C, at this time, the guide protrusion 73 of the knock button 70 is recessed into the first guide groove 36 or the second guide groove 37 (FIG. 2F) of the inner barrel 30, and the rotor's sliding ridge 67 (not shown in FIG. 5) is recessed into the first guide groove 36 (FIG. 2F) of the inner barrel 30. The guide protrusion 73 abuts against the rear end step 39 of the inner barrel 30, preventing further rearward movement. In this state, the ballpoint pen tip 53 is recessed into the front barrel 40 (FIG. 1C).

[0035] (1-6) Writing State Next, the ballpoint pen 10 in writing state will be described with reference to Figures 6A to 6C and 7. Figure 6A is a front view of the ballpoint pen 10 in writing state, Figure 6B is a side view of the ballpoint pen 10 in Figure 6A, and Figure 6C is a cross-sectional view taken along line VI-VI in Figure 6A. Figure 7 also shows an enlarged view of the rear end portion of Figure 6C.

[0036] 1A to 1C, when knock button 70 is pressed, ballpoint pen tip 53 protrudes from the tip of front barrel 40, enabling writing, as shown in Figures 6A to 6C. Until this state is reached, the following events occur inside inner barrel 30.

[0037] First, when the knock button 70 is pressed, the rotor 60 also moves forward with the rotating cam 63 engaged with the knock cam 74 as the knock button 70 moves forward. At this time, the guide protrusion 73 slides forward along the first guide groove 36 or the second guide groove 37, and at the same time, the sliding protrusion 67 slides forward along the first guide groove 36. Then, when the sliding protrusion 67 leaves the first guide groove 36, the rotating cam 63 rotates along the inclination of the inner cam 35, but stops rotating when the engaging cam 64 abuts against the inner cam 35 positioned in the rotation direction. In this state, the biasing force of the knock spring 11 presses the rotor 60 rearward from the rear end of the refill 50, and the engaging cam 64 remains engaged with the inner cam 35. This state is shown in FIG. 7.

[0038] At this time, the inclined surface 66 of the rotor 60 that abuts against the rear end of the refill 50 is pressed rearward, receiving a force that causes it to become perpendicular to the axis. This force presses the inclined cam 64A, the cam surface of the engagement cam 64 that is located furthest forward, rearward. This causes the rotor 60 to tilt toward the position of the fulcrum cam 64B. The push rod 62 inserted inside the knock button 70 then presses the knock button 70 from the inside in this inclined direction, so that the knock button 70 is clamped and fixed between the push rod 62 and the inner wall of the rear end opening 38.

[0039] In this state, the knock button 70 is free relative to the rotor 60, but since it is fixed as described above, even if there is vibration due to writing, the frictional resistance between the knock button 70 and the rotor 60 prevents the knock button 70 from vibrating.

[0040] When the knock button 70 is pressed again from this writing state, the rotor 60 is moved forward, and each of the engagement cams 64 is disengaged from the inner cam 35. The rotating cam 63 then rotates again along the cam surface of the inner cam 35, with the sliding protrusion 67 fitting into the first guide groove 36 in the rotational direction. In this state, the rotor 60 is moved rearward by the biasing force of the knock spring 11. When the guide protrusion 73 abuts against the rear end step 39, the rotor stops moving and returns to the non-writing state shown in FIGS. 1A to 1C.

[0041] (1-7) Summary of the First Embodiment As described above, the ballpoint pen 10 according to the first embodiment comprises a barrel 15, a refill 50 that is housed in the barrel 15 and whose tip protrudes from the barrel 15 in response to a knocking operation, a knock spring 11 that is interposed between the barrel 15 and the refill 50 and that urges the refill 50 rearward, a rotor 60 that has a cam formed on its rear end surface and is substantially cylindrical, a cam portion 61 that is formed with a cam and has a pressure rod 62 that protrudes rearward from the cam portion 61 and is rod-shaped with a smaller diameter, and the rotor 60 abuts against the rear end of the refill 50, and the pressure rod 62 is The rotor 60 includes a knock button 70 that is inserted into the internal space and abuts against the rear end of the cam portion 61, with a portion of it protruding from the rear end of the barrel 15, an inner cam 35 formed on the inner surface near the rear end of the barrel 15, a knock cam 74 formed on the tip surface of the knock button 70, a rotating cam 63 formed on the rear end surface of the rotor 60 and engaging with the knock cam 74, a plurality of engaging cams 64 formed on the outer periphery of the rotating cam 63 and engaging with the inner cam 35, and an inclined surface 66 that is the tip surface of the rotor 60 and inclined rearward.

[0042] The ballpoint pen 10 of the first embodiment is configured so that, when the rotor 60 is pressed by the knock button 70 and the engagement cam 64 is engaged with the inner cam 35, the refill 50 is urged rearward by the knock spring 11, the inclined surface 66 is pressed rearward by the rear end of the refill 50, and the rotor 60 inclines toward the position of the inclined surface 66 closest to the rear relative to the axis, and the pressing rod 62 presses the inner surface of the knock button 70 to fix the knock button 70 to the barrel 15.

[0043] In the ballpoint pen 10 according to the first embodiment, the plurality of engaging cams 64 are provided with an inclined cam 64A whose position at which it engages with the inner cam 35 is closer to the front than the others and which is located on the side of the inclined surface 66 closest to the front, and a fulcrum cam 64B which faces the inclined cam 64A across the axis and whose position at which it engages with the inner cam 35 is closer to the rear than the others and which is located on the side of the inclined surface 66 closest to the rear. As a result, when the inclined cam 64A engages with the inner cam 35, the rotor 60 tilts toward the fulcrum cam 64B.

[0044] (2) Second Embodiment (2-1) Overall Configuration of Ballpoint Pen 10 The overall configuration of the ballpoint pen 10 of the second embodiment will be described with reference to Figures 8A to 8C. Figure 8A is a front view of the ballpoint pen 10, Figure 8B is a side view of the ballpoint pen 10 of Figure 8A, and Figure 8C is a cross-sectional view taken along line VIII-VIII of Figure 8A. Figures 8A to 8C show the ballpoint pen 10 in a non-writing state.

[0045] As shown in Figures 8A and 8B, the appearance of the ballpoint pen 10 of the second embodiment is no different from the appearance of the ballpoint pen 10 of the first embodiment. The ballpoint pen 10 of the second embodiment has the same configuration as the ballpoint pen 10 of the first embodiment, except for the configuration of the rotor 60 shown in Figure 8C. Since the overall configuration of the ballpoint pen 10 and the structures of the inner shaft 30 and knock button 70 are the same as those of the first embodiment, a description thereof will be omitted below.

[0046] (2-2) Rotor The structure of the rotor 60 used in the ballpoint pen 10 of this embodiment will be described with reference to Figures 9A to 9G. Figure 9A is a front view of the rotor 60, Figure 9B is a side view of the rotor 60, Figure 9C is a front perspective view of the rotor 60, Figure 9D is a rear perspective view of the rotor 60, Figure 9E is a plan view of the rotor 60, Figure 9F is a bottom view of the rotor 60, and Figure 9G is a cross-sectional view taken along line IX-IX of Figure 9A.

[0047] The rotor 60 is composed of a generally cylindrical cam portion 61 on which a cam is formed, and a columnar pressure rod 62 that has a smaller diameter than the cam portion 61 and protrudes to the tip. A sawtooth rotating cam 63 with eight alternating peaks and eight valleys is formed on the tip surface of the cam portion 61 (FIG. 9D). Meanwhile, the rear edge of the cam portion 61 forms a flange 68 with an increased outer diameter. Four inner peripheral ribs 65 extending in the axial direction are evenly distributed on the inner peripheral surface of the cam portion 61 (FIGS. 9C, 9F, and 9G).

[0048] Four sliding ridges 67 extending in the axial direction are evenly spaced on the outer peripheral surface of the cam portion 61. An engaging cam 64 is formed at the tip of each sliding ridge 67 as an inclined surface whose height increases from right to left when viewed from the front. The sliding ridges 67 are positioned so that the inclination of the engaging cam 64 matches the inclination of the rotating cam 63 (FIGS. 9A, 9B, and 9D). The outer peripheral surface of the sliding ridges 67 matches the outer peripheral surface of the flange 68 (FIGS. 9A to 9D and 9E). The sliding ridges 67 are recessed into the first guide groove 36 (FIG. 2F) of the inner shaft 30 and slide back and forth along the first guide groove 36.

[0049] Of the four engagement cams 64, one has a cam surface located closer to the tip than the others, and is referred to as inclined cam 64A (FIGS. 9B, 9D, 9E). Of the four engagement cams 64, the other has a cam surface located closer to the rear end than the others, and is referred to as fulcrum cam 64B (FIGS. 9A, 9B, 9D, 9E). The cam surface of fulcrum cam 64B coincides with the cam surface of rotating cam 63 (FIGS. 9B, 9E). The engagement cams 64 other than fulcrum cam 64B and the cam surfaces of the engagement cams 64 are located closer to the tip than the cam surface of rotating cam 63 (FIGS. 9A, 9B, 9D).

[0050] The tip end surface of the rotor 60 is an inclined surface 66 that slopes backward (FIGS. 9B, 9C, 9F, and 9G). Specifically, the side of the inclined surface 66 closest to the front corresponds to the side where the inclined cam 64A is located. The side of the inclined surface 66 closest to the rear corresponds to the side where the fulcrum cam 64B is located (FIGS. 9B and 9G). Furthermore, a forward protrusion 69 protrudes toward the tip end from the side of the inclined surface 66 closest to the rear.

[0051] (2-3) Non-Writing State In the non-writing state shown in FIG. 8C, the refill 50 is biased rearward by the knock spring 11, which in turn presses the rotor 60 and knock button 70 rearward. As shown in FIG. 10, which is an enlarged view of the rear end portion of FIG. 8C, at this time, the guide protrusion 73 of the knock button 70 is recessed into the first guide groove 36 or the second guide groove 37 (FIG. 2F) of the inner barrel 30, and the rotor's sliding ridge 67 (not shown in FIG. 5) is recessed into the first guide groove 36 (FIG. 2F) of the inner barrel 30. The guide protrusion 73 abuts against the rear end step 39 of the inner barrel 30, preventing further rearward movement. In this state, the ballpoint pen tip 53 is recessed into the front barrel 40 (FIG. 8C).

[0052] (2-4) Writing State Next, the ballpoint pen 10 in writing state will be described with reference to Figures 11A to 11C and 12. Figure 11A is a front view of the ballpoint pen 10 in writing state, Figure 11B is a side view of the ballpoint pen 10 in Figure 11A, and Figure 11C is a cross-sectional view taken along line XI-XI in Figure 11A. Figure 12 shows an enlarged view of the rear end portion of Figure 12C.

[0053] When knock button 70 is pressed from the non-writing state shown in Figures 8A to 8C, ballpoint pen tip 53 protrudes from the tip of front barrel 40, making writing possible, as shown in Figures 11A to 11C. Until this state is reached, the following events occur inside inner barrel 30.

[0054] First, when the knock button 70 is pressed, the rotor 60 also moves forward with the rotating cam 63 engaged with the knock cam 74 as the knock button 70 moves forward. At this time, the guide protrusion 73 slides forward along the first guide groove 36 or the second guide groove 37, and at the same time, the sliding protrusion 67 slides forward along the first guide groove 36. Then, when the sliding protrusion 67 leaves the first guide groove 36, the rotating cam 63 rotates along the inclination of the inner cam 35, but stops rotating when the engaging cam 64 abuts against the inner cam 35 positioned in the rotation direction. In this state, the biasing force of the knock spring 11 presses the rotor 60 rearward from the rear end of the refill 50, and the engaging cam 64 remains engaged with the inner cam 35. This state is shown in Figure 12.

[0055] At this time, the inclined surface 66 of the rotor 60 that abuts against the rear end of the refill 50 is pressed backward, receiving a force that causes it to become perpendicular to the axis. At this time, the rear end of the refill 50, the side that is located on the fulcrum cam 64B side, receives a reaction force toward the right as viewed in FIG. 12 from the abutting front protrusion 69. This reaction strengthens the force that presses backward the side of the rear end of the refill 50, the side that is located on the inclined cam 64A side. This force presses backward the inclined cam 64A, the cam surface of which is located furthest forward among the engagement cams 64. As a result, the rotor 60 tilts toward the position of the fulcrum cam 64B. The push rod 62 inserted inside the knock button 70 presses the knock button 70 from the inside in this inclined direction, thereby clamping and fixing the knock button 70 between the push rod 62 and the inner wall of the rear end opening 38.

[0056] In this state, the knock button 70 is free relative to the rotor 60, but since it is fixed as described above, vibrations that accompany writing are prevented.

[0057] When the knock button 70 is pressed again from this writing state, the rotor 60 is moved forward, and each of the engagement cams 64 is disengaged from the inner cam 35. The rotating cam 63 then rotates again along the cam surface of the inner cam 35, with the sliding protrusion 67 fitting into the first guide groove 36 in the rotational direction. In this state, the rotor 60 is moved rearward by the biasing force of the knock spring 11. When the guide protrusion 73 abuts against the rear end step 39, the rotor stops moving and returns to the non-writing state shown in FIGS. 8A to 8C.

[0058] (2-5) Summary of the Second Embodiment As described above, the ballpoint pen 10 according to the second embodiment comprises a barrel 15, a refill 50 that is housed in the barrel 15 and whose tip protrudes from the barrel 15 in response to a knocking operation, a knock spring 11 that is interposed between the barrel 15 and the refill 50 and that urges the refill 50 rearward, a rotor 60 that has a cam formed on its rear end surface and is substantially cylindrical, a cam portion 61 that has a cam formed on its rear end surface and is a rod-like pressure rod 62 with a smaller diameter that protrudes rearward from the cam portion 61, and a rotor 60 that abuts against the rear end of the refill 50, and a pressure rod 62 that abuts against the rear end of the refill 50. The rotor 60 includes a knock button 70 that is inserted into the internal space and abuts against the rear end of the cam portion 61, with a portion of it protruding from the rear end of the barrel 15, an inner cam 35 formed on the inner surface near the rear end of the barrel 15, a knock cam 74 formed on the tip surface of the knock button 70, a rotating cam 63 formed on the rear end surface of the rotor 60 and engaging with the knock cam 74, a plurality of engaging cams 64 formed on the outer periphery of the rotating cam 63 and engaging with the inner cam 35, and an inclined surface 66 that is the tip surface of the rotor 60 and inclined rearward.

[0059] The ballpoint pen 10 of the second embodiment is configured so that, when the rotor 60 is pressed by the knock button 70 and the engagement cam 64 is engaged with the inner cam 35, the refill 50 is urged rearward by the knock spring 11, the inclined surface 66 is pressed rearward by the rear end of the refill 50, and the rotor 60 inclines toward the position of the inclined surface 66 closest to the rear relative to the axis, and the pressing rod 62 presses the inner surface of the knock button 70 to fix the knock button 70 to the barrel 15.

[0060] In the ballpoint pen 10 according to the second embodiment, the plurality of engaging cams 64 are provided with an inclined cam 64A whose position at which it engages with the inner cam 35 is closer to the front than the others and which is located on the side of the inclined surface 66 closest to the front, and a fulcrum cam 64B which faces the inclined cam 64A across the axis and whose position at which it engages with the inner cam 35 is closer to the rear than the others and which is located on the side of the inclined surface 66 closest to the rear. As a result, when the inclined cam 64A engages with the inner cam 35, the rotor 60 tilts toward the fulcrum cam 64B.

[0061] In the ballpoint pen 10 according to the second embodiment, a forward protrusion 69 that protrudes forward is further formed on the side of the inclined surface 66 where the fulcrum cam 64B is provided.

[0062] In both the first and second embodiments, the knock button 70 and the rotor 60 are fixed in place, but a structure in which they are fixed between the guide protrusion 73 of the knock button 70 and the second guide groove 37 of the inner shaft 30 can also achieve the effect of preventing the knock button 70 from vibrating during writing.

[0063] The embodiments of the present disclosure can be used in a retractable ballpoint pen.

Claims

a refill that is housed in the barrel and whose tip appears and disappears from the barrel when the refill is knocked; a knock spring that is interposed between the barrel and the refill and urges the refill rearward; a rotor that has a cam formed on its rear end surface, a cam portion that is generally cylindrical, and a pressure rod that protrudes rearward from the cam portion and has a smaller diameter, rod-like shape, and that abuts against the rear end of the refill; a knock button that protrudes partly from the rear end of the barrel while abutting against the rear end of the cam portion when the pressure rod is inserted into the internal space; an inner cam formed on the inside surface near the rear end of the barrel; a knock cam formed on the tip surface of the knock button; a rotating cam formed on the rear end surface of the rotor and engaging with the knock cam; a plurality of engagement cams that are formed on the outer periphery of the rotating cam and engaging with the inner periphery cam; and a sloping surface that is the tip surface of the rotor and inclined rearward. A ballpoint pen formed as follows: when the rotor is pressed by the knock button and the engagement cam is engaged with the inner cam, the refill is urged rearward by the knock spring, the inclined surface is pressed rearward by the rear end of the refill, and the rotor inclines toward the side of the inclined surface that is closest to the rear with respect to the axis, and the pressure rod presses the inner surface of the knock button to fix the knock button to the barrel.

2. The ballpoint pen of claim 1, wherein the plurality of engaging cams include an inclined cam whose position at which it engages with the inner cam is closer to the front than the others and is located on the side of the inclined surface closest to the front, and a fulcrum cam which faces the inclined cam across the axis and whose position at which it engages with the inner cam is closer to the rear than the others and is located on the side of the inclined surface closest to the rear, and wherein the rotor tilts toward the fulcrum cam when the inclined cam engages with the inner cam.

3. The ballpoint pen according to claim 2, wherein a forward protrusion that protrudes forward is formed on the side of the inclined surface where the fulcrum cam is provided.

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