Disappearance-style notebook

Abstract

Provided is a retractable writing instrument with which a stable writing feel is obtained by preventing any unwanted movement of the tip while writing, and little risk of unsatisfactory operation is presented.　The present invention comprises: a barrel having an opening at the front end; a tip holder that can move in the axial direction of the barrel; a tip that can retract or extend along with the movement of the tip holder; an annular member that is loosely fitted in the inner periphery of the opening of the barrel and is capable of moving in the axial direction; and an elastic member that can connect the tip holder and the annular member so as to allow relative movement therebetween. A tapered contact surface is formed toward the front end in at least part of the outer periphery of the annular member, and a notch is formed in the part of the annular member, the inner diameter of the annular member decreasing when the contact surface is subjected to a load. A tapered guide surface is formed toward the front end in a part of the inner surface of the barrel, the contact surface being subjected to the load from the guide surface along with movement toward the front-end side of the tip holder.

Description

[Technical Field]

[0001] The present invention relates to a retractable writing instrument in which a tip can be projected and retracted from an opening in a barrel as a tip holder moves. [Background technology]

[0002] Patent Document 1 discloses a device for preventing the writing tip from shaking. The device is configured by providing a groove at an appropriate position on the writing tip, and fitting an elastic O-ring with an outer diameter approximately equal to the inner diameter of the barrel tip into the groove. This device can prevent rattling noises that occur when the writing tip comes into contact with the tip hole at the barrel tip during writing in pencil-type and knock-type writing instruments.

[0003] Patent Document 2 also discloses a device for preventing the writing tip from shaking. This device is configured by engaging an elastic ring with an inner diameter slightly smaller than the outer diameter of the writing tip with a locking step provided inside the tip of the barrel. With this device, because the elastic ring locks the writing tip, it is possible to prevent rattling during writing even if there is a gap between the inner diameter of the tip of the barrel and the writing tip.

[0004] Patent Document 3 discloses a writing implement that slides back and forth relative to a barrel to advance a writing part of a writing body from an opening in the barrel. An annular member is disposed on the outer periphery of the tip of the writing body, and a substantially spherical inner surface against which the annular member abuts is formed on the inner surface around the opening at the tip of the barrel from which the writing part emerges and retracts. The annular member is fixed to the writing body via a spring and is biased forward. When the writing part is advanced, the resilient force of the spring causes the annular member to adhere tightly to the inner surface of the tip of the barrel. This prevents rattling during writing.

[0005] Patent Document 4 filed by the present applicant discloses four types of configurations of retractable writing implements that prevent tip rattle.

[0006] <First type of Patent Document 4> Fig. 11 is a schematic vertical cross-sectional view of a retractable writing instrument 110 of the first type of Patent Document 4, showing a state in which the tip 114 (writing element) is not protruding. Fig. 12(a) is an enlarged vertical cross-sectional view of the tip portion of the retractable writing instrument 110 of the first type, and Fig. 12(b) is a cross-sectional view taken along line AA in Fig. 12(a). Fig. 13(a) is an enlarged vertical cross-sectional view of the tip portion of the retractable writing instrument 110 of the first type in a state in which the tip 114 (writing element) is protruding, and Fig. 13(b) is a cross-sectional view taken along line BB in Fig. 13(a).

[0007] Also, Figure 14(a) is an oblique view of the annular member 115 of the first type of retractable writing instrument 110, Figure 14(b) is a side view of the annular member 115, Figure 14(c) is a cross-sectional view along line CC of Figure 14(b), Figure 14(d) is a front view of the annular member 115 (viewed from the tip side), and Figure 14(e) is a back view of the annular member 115.

[0008] Furthermore, FIG. 15 is a schematic diagram showing the first type of retractable writing implement 110 with the tip holder 113 pulled out for replacement or the like.

[0009] A first type of retractable writing instrument 110 shown in Figures 11 to 15 includes a cylindrical barrel 111 having an opening at the front end. As shown in Figures 11 to 13, the first type of barrel 111 includes a rear portion 111a, an inner barrel portion 111b, a front portion 111c, and a base portion 111d, with the rear portion 111a and inner barrel portion 111b being removably fixed by a screw connection (threaded engagement), and the inner barrel portion 111b and the front portion 111c being integrally formed by two-color molding. Meanwhile, the base portion 111d is removably fixed to the inner barrel portion 111b by a screw connection (threaded engagement).

[0010] A tip holder 113 that is movable in the axial direction of the barrel 111 is housed inside the barrel 111. A tip 114, which is a writing element, is fixed to the front end of the tip holder 113. The tip 114 can appear and disappear from the opening of the barrel 111 as the tip holder 113 moves, as shown in Figures 12(a) and 13(a).

[0011] 15, the tip holder 113 has, in this order from the base end to the tip end, a base end portion 113a, a first collar portion 113b, a second collar portion 113c, a spring fixing auxiliary portion 113f, and a tip end portion 113d. The base end portion 113a, the first collar portion 113b, the second collar portion 113c, the spring fixing auxiliary portion 113f, and the tip end portion 113d are all cylindrical portions, and the relationship between their cross-sectional diameters is base end portion 113a > first collar portion 113b > second collar portion 113c > spring fixing auxiliary portion 113f > tip end portion 113d.

[0012] 12(b), a resin or metal annular member 115 is loosely fitted around the outer periphery of the tip end 113d of the chip holder 113. The annular member 115 is fixed to the second collar portion 113c of the chip holder 113 via a coil spring 116 (an example of an elastic member) that similarly loosely fits around the outer periphery of the tip end 113d of the chip holder 113 (with a small gap). This allows the annular member 115 to move in the axial direction of the chip holder 113 relative to the tip end 113d of the chip holder 113 as the coil spring 116 expands and contracts.

[0013] The chip holder 113 is provided with a spring fixing auxiliary portion 113f to assist in fixing the coil spring 116 to the second collar portion 113c.

[0014] 14(a) to 14(e), a truncated conical contact surface 115t is formed as a contact surface tapering toward the front end in a front region of the outer periphery of the annular member 115. A large outer diameter cylindrical portion 115a is provided continuously behind the contact surface 115t, and a small outer diameter cylindrical portion 115b is provided further behind the large outer diameter cylindrical portion 115a via a step.

[0015] The annular member 115 has four slits 115s formed as cutouts. As shown in FIGS. 14(a) to 14(e), the four slits 115s are arranged at equal intervals (every 90°) around the circumference of the annular member 115. Each of the four slits 115s extends in the axial direction of the annular member 115 from the front end to approximately the center of the small outer diameter cylindrical portion 115b. This allows the inner diameter of the annular member 115 to flexibly contract when a load is applied to the abutment surface 115t, and also allows the inner diameter of the annular member 115 to elastically return to its original shape when the load is released.

[0016] 12(a) and 13(a), a guide surface 111t in the shape of a concave truncated cone is formed as a guide surface tapering toward the front end on part of the inner surface of the mouthpiece portion 111d of the barrel 111. As a result, the abutment surface 115t is adapted to receive a load from the guide surface 111t as the tip holder 113 moves toward the front end (FIG. 12(a) → FIG. 13(a)).

[0017] The first type of retractable writing implement 110 is also provided with a second coil spring 112 (second elastic member) for automatically retracting the tip holder 113 when the tip 114 is retracted (for example, by pressing a push button provided at the rear end of the writing implement to release a locking mechanism that maintains the protruding state of the tip 114). The second coil spring 112 is inserted between a shoulder provided on the inner surface of the base portion 111d and the first collar portion 113b of the tip holder 113 so as to further surround the outer periphery of the coil spring 116.

[0018] The second coil spring 112 may be fixed to the inner surface of the base portion 111d, or may be free (not fixed to any member), or may be fixed to the first collar portion 113b of the tip holder 113.

[0019] The first type of retractable writing implement 110 described above operates as follows.

[0020] When not in use, the tip 114 (writing element) of the retractable writing instrument 110 is in a retracted state as shown in FIG. 12(a). At this time, the axial length of the coil spring 116 is 8.2 mm, and the axial length of the second coil spring 112 is 16.4 mm. When the tip is extended (for example, by pressing a push button provided at the rear end of the writing instrument), the tip 114 (writing element) of the retractable writing instrument 110 enters a protruding state as shown in FIG. 13(a). Normally, the position of the tip holder 113 is locked in this protruding state, and the protruding state of the tip 114 is maintained until the tip is subsequently retracted. At this time, the axial length of the coil spring 116 is 5.6 mm (compressed 2.6 mm), and the axial length of the second coil spring 112 is 9.4 mm (compressed 7.0 mm).

[0021] 12(a) to the protruding state of FIG. 13(a), as the tip holder 113 moves toward the front end, the abutment surface 115t of the annular member 115 receives a load from the guide surface 111t of the mouthpiece 111d. At this time, the four slits 115s in the annular member 115 cause the inner diameter of the annular member 115 to decrease (FIG. 12(b) → FIG. 13(b)). As a result, as shown in FIG. 13(b), the mouthpiece 111d and the annular member 115 cooperate to grip the tip end 113d of the tip holder 113 without any rattle (play).

[0022] Furthermore, since the chip holder 113 and the annular member 115 are connected by the coil spring 116 so that they can move relative to each other, it is possible to ensure that the tip portion 113d of the chip holder 113 is effectively gripped without any rattle (play) even without high-precision dimensional control over the degree of reduction in the inner diameter of the annular member 115.

[0023] Thereafter, when the tip is retracted (for example, by pressing the push button at the rear end of the writing instrument again), a locking mechanism (not shown) is released, and the tip 114 (writing body) of the retractable writing instrument 110 returns to the retracted state shown in Figure 12(a) by the action of the second coil spring 112.

[0024] 12(a) from the protruding state of Fig. 13(a) to the retracted state of Fig. 12(a), as the tip holder 113 moves toward the rear end, the load that the abutment surface 115t of the annular member 115 has been receiving from the guide surface 111t of the mouthpiece 111d disappears, and the inner diameter of the annular member 115, which had been reduced, returns to its original state (Fig. 13(b) → Fig. 12(b)).

[0025] <Second type of Patent Document 4> Fig. 16 is an enlarged vertical cross-sectional view of the tip portion of a retractable writing instrument 120 of the second type in Patent Document 4, and Fig. 17 is an enlarged vertical cross-sectional view of the tip portion of the retractable writing instrument 120 of the second type in a state in which the tip 124 (writing element) is protruding. Furthermore, Fig. 18 is a schematic view showing the state in which the tip holder 123 (base end portion 123a, first collar portion 123b, second collar portion 123c, and tip portion 123d) has been pulled out for replacement or the like in the retractable writing instrument 120 of the second type.

[0026] The second type retractable writing instrument 120 is provided with a cylindrical resin spring portion 126e instead of the coil spring 116 in the first type retractable writing instrument 110. The resin spring portion 126e has six pairs of approximately semicircular slits that face each other vertically and six pairs of approximately semicircular slits that face each other horizontally, alternately arranged in the axial direction. This allows the resin spring portion 126e to expand and contract in the axial direction.

[0027] Furthermore, the resin spring portion 126e is integrally molded with the annular member 125. The annular member 125 is provided with four slits 125s as cutouts, substantially similar to the annular member 115 of the first type of retractable writing instrument 110.

[0028] The second type retractable writing instrument 120 also provides substantially the same effects as the first type retractable writing instrument 110. That is, the mouth portion 111d and the annular member 125 (the contact surface 125t) work together to hold the tip portion 123d of the tip holder 123 without any rattle (play).

[0029] <Third type of Patent Document 4> Fig. 19 is an enlarged vertical cross-sectional view of the tip portion of a retractable writing instrument 130 of the third type in Patent Document 4, and Fig. 20 is an enlarged vertical cross-sectional view of the tip portion of the retractable writing instrument 130 of the third type in a state in which the tip 134 (writing element) is protruding. Furthermore, Fig. 21 is a schematic view showing a state in which the tip holder 133 (base end portion 133a, middle collar portion 133m and tip portion 133d) has been pulled out for replacement or the like in the retractable writing instrument 130 of the third type.

[0030] The third type of retractable writing instrument 130 has a collar member 132 (first collar portion 133b and second collar portion 133c) fixed to the rear end of the coil spring 112 (second elastic member) of the first type of retractable writing instrument 110, and the rear end of the coil spring 116 (elastic member) whose front end is connected to the annular member 115 is fixed to the collar member 132 instead of the second collar portion 113c of the tip holder 113.

[0031] The third type retractable writing instrument 130 also provides substantially the same effects as the first type retractable writing instrument 110. That is, the mouth portion 111d and the annular member 115 cooperate to hold the tip portion 133d of the tip holder 133 without any rattle (play).

[0032] Furthermore, with the third type of retractable writing implement 130, there is no need to provide the annular member 115 on the tip holder 133, so existing replacement refills with conventional tip holders can also be used.

[0033] <Fourth type of Patent Document 4> Fig. 22 is an enlarged vertical cross-sectional view of the tip portion of a retractable writing instrument 140 of the fourth type in Patent Document 4, and Fig. 23 is an enlarged vertical cross-sectional view of the tip portion of the retractable writing instrument 140 of the fourth type in a state in which the tip 144 (writing element) is protruding. Furthermore, Fig. 24 is a schematic view showing a state in which the tip holder 143 (base end portion 143a, middle collar portion 143m and tip portion 143d) has been pulled out for replacement or the like in the retractable writing instrument 140 of the fourth type.

[0034] The fourth type of retractable writing instrument 140 has a collar member 142 (first collar member 143b and second collar member 143c) fixed to the rear end of the resin spring member 126 (second elastic member) of the second type of retractable writing instrument 120, and the rear end of the resin spring member 126 (elastic member), whose front end is integrated with the annular member 125, is fixed to the collar member 142 rather than the second collar member 123c of the tip holder 123.

[0035] The fourth type retractable writing instrument 140 also provides substantially the same effects as the second type retractable writing instrument 120. That is, the mouth portion 111d and the annular member 125 cooperate to hold the tip portion 143d of the tip holder 143 without any rattle (play).

[0036] Furthermore, with the fourth type of retractable writing implement 140, there is no need to provide the annular member 125 on the tip holder 143, so existing replacement refills with conventional tip holders can also be used. [Prior art documents] [Patent documents]

[0037] [Patent Document 1] Jpn. Appl. KOKAI Publication No. 5-85683 [Patent Document 2] Jpn. Appl. KOKAI Publication No. 5-93884 [Patent Document 3] Patent Publication No. 2013-220602 [Patent Document 4] Patent Publication No. 2019-111657 Summary of the Invention [Problem to be solved by the invention]

[0038] The techniques disclosed in Patent Documents 1 and 2 are insufficient in preventing rattle because the O-ring can deform radially. Also, the writing tip can get stuck on the surface of the O-ring, making it difficult to smoothly retract the extended writing tip.

[0039] On the other hand, with the technology disclosed in Patent Document 3, in order to enhance the effect of preventing wobbling during writing, it is necessary to properly manage the dimensional relationship between the inner surface of the annular member and the outer surface of the writing part. For example, if the gap dimension between the outer surface of the writing part and the inner surface of the annular member is larger than the gap dimension between the outer surface of the writing part and the inner surface of the tip of the barrel, the effect of preventing wobbling during writing cannot be obtained. This requires high dimensional accuracy, which poses a problem in terms of productivity.

[0040] Furthermore, in the first and fourth type configurations of Patent Document 4, two types of coil springs 112, 116 are used in combination, and these coil springs 112, 116 may get caught on each other during assembly or refill replacement, which may impair the smoothness of the work. Furthermore, when the coil springs 112, 116 contract as the tip holders 113, 123, 133, and 143 extend and retract, these coil springs 112, 116 may get tangled, which may cause malfunction.

[0041] On the other hand, in the second and third type configurations of Patent Document 4, it is difficult to increase the degree of expansion and contraction (deflection amount) of the resin spring portion 126, and therefore the degree of freedom in design is low.

[0042] The present invention was made in consideration of the above findings, and its purpose is to provide a retractable writing instrument that prevents the tip from rattling when writing, providing a stable writing feel, while also reducing the risk of malfunction. [Means for solving the problem]

[0043] The present invention comprises a barrel having an opening at a front end, a chip holder accommodated inside the barrel and movable in the axial direction of the barrel, a chip fixed to the front end of the chip holder and movable in and out of the opening of the barrel as the chip holder moves, an annular member loosely fitted into the inner periphery of the opening of the barrel and movable in the axial direction of the barrel relative to the barrel, and an elastic member connecting the chip holder and the annular member so that they can move relative to each other, wherein at least a portion of the outer periphery of the annular member is formed with an abutment surface that abuts against a portion of the inner surface of the barrel as the chip holder moves toward the front end, and a notch is formed in a portion of the annular member so that the inner diameter of the annular member decreases when a load is received at the abutment surface, and a guide surface is formed on a portion of the inner surface of the barrel against which the abutment surface abuts as the chip holder moves toward the front end, and the abutment surface receives the load from the guide surface as the chip holder moves toward the front end. This is a retractable writing instrument characterized by the above.

[0044] According to the present invention, as the tip holder moves toward the front end, the contact surface of the annular member receives a load from the guide surface of the barrel, and the presence of the notch in the annular member causes the inner diameter of the annular member to decrease, allowing the barrel and the annular member to cooperate to grip the tip or tip holder without any rattle (play).

[0045] Furthermore, according to the present invention, the elastic member can function as a knock spring, eliminating the need for a separate coil spring for the knock spring. This reduces the number of parts, simplifies assembly, and significantly reduces the risk of malfunction.

[0046] Preferably, the gripping portion of the annular member that grips the tip or tip holder is located forward of the contact surface of the annular member (there is no gripping portion radially inward of the contact surface). This allows the tip or tip holder to be gripped further forward, and the tip or tip holder can be gripped more effectively without any rattle (play).

[0047] Preferably, the barrel and / or the annular member is provided with a stopper element that defines the rearward movement limit of the annular member, which can effectively prevent excessive movement (especially detachment) of the annular member.

[0048] Preferably, a plurality of the notches are arranged at equal intervals in the circumferential direction of the annular member, and each of the plurality of notches is a slit extending in the axial direction of the annular member. In this case, the inner diameter of the annular member can be reduced in a balanced manner in the circumferential direction.

[0049] In this case, it is further preferable that the rear end of the slit is located forward of the elastic member, so that a stable connection between the elastic member and the annular member can be maintained even when the annular member is bent due to the presence of the slit.

[0050] The abutment surface preferably tapers toward the front end, and the guide surface preferably tapers toward the front end as well. The abutment surface preferably has, for example, a truncated conical surface. In this case, the guide surface preferably has a corresponding concave truncated conical surface. Alternatively, the abutment surface preferably has a convex curved surface that is rotationally symmetric about an axis. In this case, the guide surface preferably has a concave curved surface or a concave truncated conical surface that is rotationally symmetric about an axis and has a curvature that is gentler than the curvature of the convex curved surface.

[0051] Preferably, the elastic member is a coil spring.

[0052] Preferably, the annular member and the elastic member are fixed to each other, the elastic member is connectable to an annular collar of the tip holder, and the elastic member is separable from the annular collar of the tip holder. In this case, the annular member and the elastic member are held only on the barrel side, so that existing replacement refills having conventional tip holders can be used.

[0053] Preferably, the abutment surface and the guide surface are always in abutment with each other. In this case, the annular member and the inner surface of the barrel do not repeatedly come into contact with and separate from each other every time the tip is extended or retracted, so operation is stable and the user feels smooth (no discomfort) when operating the tip.

[0054] Preferably, the annular member protrudes forward from the opening of the barrel, which allows the tip or tip holder to be gripped over a longer range, ensuring more effective gripping of the tip or tip holder without rattle (play).

[0055] In this case, it is further preferable that the amount (length) by which the annular member protrudes forward from the opening of the barrel be smaller than the axial movable range of the annular member. In this way, even when the annular member is pushed into the opening of the barrel so as to be immersed, the annular member remains within the axial movable range, thereby preventing the annular member from undesirably falling off, etc.

[0056] Preferably, a soft member is provided at the operating portion for extending and retracting the tip or at the rear of the barrel. When a conventional configuration is used in a thermochromic writing instrument, there is a risk that the tip or tip holder will rattle due to vibrations caused by rubbing when writing, which can cause noise. However, the configuration of the present invention does not have this risk. Therefore, it is recommended that the configuration of the present invention be used in a thermochromic writing instrument. Preferably, the device further includes a knock member slidable in the front-rear direction relative to the barrel, and the tip is moved back and forth so as to alternately protrude and retract from the opening of the barrel each time the knock member is moved forward, and the annular member is rotated relative to the barrel each time the knock member is moved forward. In this way, the annular member rotates as the knock member moves forward (operation), allowing the user to visually recognize the rotation of the annular member. This provides visual interest to the user.

[0057] The present invention also covers only the barrel of the retractable writing instrument. In other words, the present invention is a barrel for a retractable writing instrument that can accommodate a tip holder with a tip fixed to the front end so that it can move axially, has an opening at the front end, and can cause the tip to protrude and retract from the opening as the tip holder moves, and is characterized in that it comprises: an annular member that is loosely fitted into the inner circumference of the opening of the barrel and is movable axially relative to the barrel; an elastic member that can connect the tip holder and the annular member so that they can move relative to each other; at least a portion of the outer circumference of the annular member is formed with an abutment surface that abuts against a portion of the inner surface of the barrel as the tip holder moves toward the front end, a notch is formed in a portion of the annular member so that the inner diameter of the annular member decreases when a load is received at the abutment surface; and a guide surface is formed on a portion of the inner surface of the barrel against which the abutment surface abuts as the tip holder moves toward the front end, and the abutment surface is configured to receive the load from the guide surface as the tip holder moves toward the front end. [Effects of the Invention]

[0058] According to the present invention, as the tip holder moves toward the front end, the contact surface of the annular member receives a load from the guide surface of the barrel, causing the inner diameter of the annular member to decrease due to the presence of the notch in the annular member. This allows the barrel and the annular member to cooperate to grip the tip or tip holder without any play (play). Furthermore, according to the present invention, the elastic member can function as a "knock spring," eliminating the need for a separate coil spring for the knock spring. This reduces the number of parts, simplifies assembly, and significantly reduces the risk of malfunction. [Brief explanation of the drawings]

[0059] [Figure 1] FIG. 1 is a schematic vertical cross-sectional view of a retractable writing instrument according to a first embodiment of the present invention, showing a state in which a tip (writing element) is not protruding. [Figure 2] FIG. 2 is an enlarged vertical cross-sectional view of the tip portion of the retractable writing instrument of FIG. [Figure 3] FIG. 3(a) is a perspective view of the annular member of the retractable writing instrument of FIG. 1. FIG. 3(b) is a plan view of the annular member of FIG. 3(a). FIG. 3(c) is a side view of the annular member of FIG. 3(a). FIG. 3(d) is a bottom view of the annular member of FIG. 3(a). FIG. 3(e) is a cross-sectional view taken along line AA of FIG. 3(c). FIG. 3(f) is a front view (view from the tip side) of the annular member of FIG. 3(a). FIG. 3(g) is a back view of the annular member of FIG. 3(a). [Figure 4] 2 is a schematic view showing a state in which the tip comes into contact with the annular member during the tip protrusion operation in the retractable writing instrument of FIG. 1. FIG. [Figure 5] 2 is a schematic diagram showing the state in which the tip of the retractable writing instrument of FIG. 1 is most protruded during the tip protrusion operation. FIG. [Figure 6] 2 is a schematic diagram showing the tip of the retractable writing instrument of FIG. 1 in a protruding state after the tip protruding operation has been completed. FIG. [Figure 7] FIG. 10 is a schematic vertical cross-sectional view of a retractable writing instrument according to a second embodiment of the present invention, showing a state in which the tip (writing element) is not protruding. [Figure 8] Fig. 8(a) is a perspective view of the annular member of the retractable writing instrument of Fig. 7. Fig. 8(b) is a plan view of the annular member of Fig. 8(a). Fig. 8(c) is a side view of the annular member of Fig. 8(a). Fig. 8(d) is a bottom view of the annular member of Fig. 8(a). Fig. 8(e) is a cross-sectional view taken along line AA of Fig. 8(b). Fig. 8(f) is a front view (view from the tip side) of the annular member of Fig. 8(a). Fig. 8(g) is a back view of the annular member of Fig. 8(a). [Figure 9] FIG. 10 is a schematic vertical cross-sectional view of a retractable writing instrument according to a third embodiment of the present invention, showing a state in which the tip (writing element) is not protruding. [Figure 10] Fig. 10(a) is a perspective view of the annular member of the retractable writing instrument of Fig. 9. Fig. 10(b) is a plan view of the annular member of Fig. 10(a). Fig. 10(c) is a side view of the annular member of Fig. 10(a). Fig. 10(d) is a bottom view of the annular member of Fig. 10(a). Fig. 10(e) is a cross-sectional view taken along line AA of Fig. 10(b). Fig. 10(f) is a front view (view from the tip side) of the annular member of Fig. 10(a). Fig. 10(g) is a back view of the annular member of Fig. 10(a). [Figure 11] FIG. 1 is a schematic vertical cross-sectional view of a retractable writing implement of the first type disclosed in Patent Document 4, showing a state in which the tip (writing element) is not protruding. [Figure 12] Figure 12(a) is an enlarged vertical cross-sectional view of the tip portion of a first type of retractable writing implement of Patent Document 4. Figure 12(b) is a cross-sectional view taken along line AA of Figure 12(a). [Figure 13] Figure 13(a) is an enlarged vertical cross-sectional view of the tip portion of the first type of retractable writing instrument of Patent Document 4 in a state where the tip (writing element) is protruding. Figure 13(b) is a cross-sectional view taken along line BB in Figure 13(a). [Figure 14] Fig. 14(a) is a perspective view of the annular member of the first type of retractable writing implement of Patent Document 4. Fig. 14(b) is a side view of the annular member of Fig. 14(a). Fig. 14(c) is a cross-sectional view taken along line CC of Fig. 14(b). Fig. 14(d) is a front view (viewed from the tip side) of the annular member of Fig. 14(a). Fig. 14(e) is a rear view of the annular member of Fig. 14(a). [Figure 15] FIG. 10 is a schematic view showing a state in which the tip holder has been pulled out for replacement or the like in the first type of retractable writing instrument of Patent Document 4. [Figure 16] FIG. 10 is an enlarged vertical cross-sectional view of the tip portion of a retractable writing implement of the second type disclosed in Patent Document 4. [Figure 17] FIG. 10 is an enlarged vertical cross-sectional view of the tip portion of a second type of retractable writing implement of Patent Document 4 in a state where the tip (writing element) is protruding. [Figure 18] FIG. 10 is a schematic view showing a state in which the tip holder has been pulled out for replacement or the like in the second type of retractable writing instrument of Patent Document 4. [Figure 19] FIG. 10 is an enlarged vertical cross-sectional view of the tip portion of a retractable writing implement of the third type disclosed in Patent Document 4. [Figure 20] FIG. 10 is an enlarged vertical cross-sectional view of the tip portion of a third type of retractable writing implement of Patent Document 4 in a state where the tip (writing element) is protruding. [Figure 21] FIG. 10 is a schematic view showing a state in which the tip holder has been pulled out for replacement or the like in the third type of retractable writing instrument of Patent Document 4. [Figure 22] FIG. 10 is an enlarged vertical cross-sectional view of the tip portion of a retractable writing implement of the fourth type disclosed in Patent Document 4. [Figure 23] FIG. 10 is an enlarged vertical cross-sectional view of the tip portion of a fourth type of retractable writing implement of Patent Document 4 in a state where the tip (writing element) is protruding. [Figure 24] FIG. 10 is a schematic view showing a state in which the tip holder has been pulled out for replacement or the like in the fourth type of retractable writing instrument of Patent Document 4. [Figure 25] FIG. [Figure 26] FIG. 2 is a perspective view of the rear end portion of the refill. [Figure 27] FIG. 2 is a plan view of the rear end portion of the refill. [Figure 28] FIG. 1 is a longitudinal cross-sectional view of a front barrel of an exemplary barrel. [Figure 29] FIG. 2 is a longitudinal cross-sectional view of an intermediate shaft of an exemplary barrel. [Figure 30] FIG. 1 is a longitudinal cross-sectional view of an exemplary rear barrel. [Figure 31] FIG. 2 is a vertical cross-sectional view of a knock member. [Figure 32] FIG. [Figure 33] FIG. [Figure 34] FIG. [Figure 35] 33 is a cross-sectional view taken along line CC in FIG. 32. [Figure 36] 1 is a schematic diagram illustrating the principle of a rotation cam mechanism. [Figure 37] 10 is a vertical cross-sectional view showing a state in which the retractable rotary member and the rear end of the refill are in contact with each other. FIG. [Figure 38] 10 is a perspective view showing a state in which the retractable rotary member and the rear end of the refill are in contact with each other. FIG. [Figure 39] FIG. 3 is a view corresponding to FIG. 2, showing an embodiment in which the winding direction of the coil spring is reversed. [Figure 40] FIG. 3(e) is a view corresponding to FIG. 3(e) in which the first frustoconical inner surface has been replaced by a chamfer. [Figure 41] Figure 41(a) is a perspective view of an annular member of a retractable writing implement of a modified example. Figure 41(b) is a plan view of the annular member of Figure 41(a). Figure 41(c) is a side view of the annular member of Figure 41(a). Figure 41(d) is a bottom view of the annular member of Figure 41(a). Figure 41(e) is a cross-sectional view taken along line AA of Figure 41(c). Figure 41(f) is a front view (view from the tip side) of the annular member of Figure 41(a). Figure 41(g) is a back view of the annular member of Figure 41(a). DETAILED DESCRIPTION OF THE INVENTION

[0060] Three embodiments of the present invention will now be described with reference to the drawings.

[0061] First Embodiment Fig. 1 is a schematic vertical cross-sectional view of a retractable writing instrument 10 according to a first embodiment of the present invention, showing a state in which a tip 14 (writing element) is not protruding. Fig. 2 is an enlarged vertical cross-sectional view of the tip portion of the retractable writing instrument 10 according to this embodiment.

[0062] 3(a) is an oblique view of the annular member 15 of the retractable writing instrument 10 of this embodiment, FIG. 3(b) is a plan view of the annular member 15 of FIG. 3(a), FIG. 3(c) is a side view of the annular member 15 of FIG. 3(a), FIG. 3(d) is a bottom view of the annular member of FIG. 3(a), FIG. 3(e) is a cross-sectional view along line AA of FIG. 3(c), FIG. 3(f) is a front view (viewed from the tip side) of the annular member of FIG. 3(a), and FIG. 3(g) is a back view of the annular member of FIG. 3(a).

[0063] Furthermore, Figure 4 is a schematic diagram showing the state in which tip 14 comes into contact with annular member 15 during the protruding operation of tip 14 in the retractable writing instrument 10 of this embodiment, Figure 5 is a schematic diagram showing the state in which tip 14 is at its most protruding during the protruding operation of tip 14 in the retractable writing instrument 10 of this embodiment, and Figure 6 is a schematic diagram showing the protruding state of tip 14 after the protruding operation of tip 14 has been completed in the retractable writing instrument 10 of this embodiment.

[0064] The retractable writing instrument 10 of the first embodiment shown in Figures 1 to 6 includes a cylindrical barrel 11 having an opening at the front end. As shown in Figures 1 to 3, the barrel 11 in this embodiment has a rear portion 11r and a front portion 11m. The rear portion 11r and the front portion 11m are removably fixed by a screw connection (threaded engagement). However, the rear portion 11r and the front portion 11m may also be fixed by a fitting connection, or may be formed integrally.

[0065] A tip holder 13 that is movable in the axial direction of the barrel 11 is housed inside the barrel 11. A tip 14, which is a writing element, is fixed to the front end of the tip holder 13. The tip 14 can appear and disappear from the opening of the barrel 11 as the tip holder 13 moves, as shown in Figures 4 to 6.

[0066] 2, the tip holder 13 has, in this order from the base end to the tip end, a base end portion 13a, a first collar portion 13b, and a second collar portion 13c. In this embodiment, the base end portion 13a and the first collar portion 13b are both cylindrical, and the second collar portion 13c is a frustoconical portion in this embodiment, with the relationship of their cross-sectional diameters being base end portion 13a > first collar portion 13b > second collar portion 13c.

[0067] 2, in this embodiment, an annular member 15 that is movable in the axial direction of the barrel 11 relative to the barrel 11 is loosely fitted around the inner periphery of the opening of the barrel 11. The front end of the annular member 15 is located forward of the front end of the barrel 11. The rear side of the annular member 15 has an expanded outer diameter and an expanded inner diameter, and covers the periphery of the tip 14 (φ2.5) without contacting it.

[0068] The annular member 15 is fixed to the front end of a coil spring 16 (an example of an elastic member). The coil spring 16 surrounds the second collar portion 13c of the tip holder 13 and the tip 14 in a loose fit (with a gap), and the rear end of the coil spring 16 is constantly pressed by the base end portion 13a of the tip holder 13 (it is not fixed). As a result, the coil spring 16 connects the tip holder 13 and the annular member 15 so that they can move relative to each other. As shown in FIGS. 4 to 6, the annular member 15 can move in the axial direction of the barrel 11 with respect to the barrel 11 as the tip holder 13 moves and the coil spring 16 expands and contracts.

[0069] The annular member 15 is made of resin (for example, polyacetal, polypropylene, or polyethylene) or metal (for example, brass).

[0070] As shown in Figures 3(a) to 3(g), the outer peripheral surface of the annular member 15 is provided with, in this order from the front side, a small outer diameter cylindrical surface 15a (φ3.6 mm, axial length 1.6 mm), a first truncated conical outer surface 15b (axial length 1.1 mm) as a tapered abutment surface, a medium outer diameter cylindrical surface 15c (φ4.85 mm, axial length 1.5 mm), a second truncated conical outer surface 15d (axial length 1.6 mm) as a tapered abutment surface, a first large outer diameter cylindrical surface 15e (φ6.3 mm, axial length 0.8 mm), a third truncated conical outer surface 15f (axial length 0.4 mm) as a tapered abutment surface, and a second large outer diameter cylindrical surface 15g (φ6.6 mm, axial length 3.3 mm).

[0071] 3(e), the inner peripheral surface of the annular member 15 is provided with, from the front side, a small-inner-diameter cylindrical surface 15ia (φ3 mm, axial length 2 mm), a first truncated conical inner surface 15ib (axial length 0.5 mm), a medium-inner-diameter cylindrical surface 15ic (φ3.6 mm, axial length 3.9 mm), a second truncated conical inner surface 15id (axial length 0.4 mm), a four-sided sweep portion 15ie (inscribed circle φ5.28 mm, axial length 0.9 mm), a large-inner-diameter cylindrical surface 15if (φ5.43 mm, axial length 2.1 mm), and a third truncated conical inner surface 15ig (axial length 0.4 mm), in that order. As shown in FIG. 2, in this embodiment, the front end of the coil spring 16 is fixed (fitted) onto the four-sided sweep portion 15ie.

[0072] Furthermore, three slits 15s are provided as cutouts in the annular member 15 of this embodiment. As shown in Figures 3(a) to 3(g), the three slits 15s are arranged at equal intervals (every 120°) around the circumference of the annular member 15. Each of the three slits 15s has a width of 0.8 mm and extends in the axial direction of the annular member 15 from the front end to approximately the center of the second frusto-conical outer surface 15d (maximum axial length: 5.5 mm).

[0073] As a result, when a load is applied to the first truncated cone outer surface 15b (contact surface), the inner diameter of the annular member 15 flexibly contracts, and when the load is released, the inner diameter of the annular member 15 elastically returns to its original state.

[0074] On the other hand, as shown in Figures 2, 5 and 6, the inner surface near the opening of the barrel 11 is provided with, in that order from the front side, a small inner diameter cylindrical surface 11ia (φ3.7 mm, axial length 1.2 mm), a first truncated conical inner surface 11ib (axial length 1.1 mm) as a tapered guide surface, a medium inner diameter cylindrical surface 11ic (φ4.95 mm, axial length 1.3 mm), a second truncated conical inner surface 11id (axial length 1.7 mm) as a tapered guide surface, a first large inner diameter cylindrical surface 11ie (φ6.5 mm, axial length 0.8 mm), a third truncated conical inner surface 11if (axial length 0.3 mm), a second large inner diameter cylindrical surface 11ig (φ6.7 mm, axial length 4.2 mm), and an annular protrusion 11ih (minimum aperture diameter φ6.5 mm) as a regulating element.

[0075] As a result, the first truncated cone outer surface 15b (contact surface) receives loads from the first truncated cone inner surface 11ib and the second truncated cone inner surface 11id (guide surfaces) as the chip holder 13 moves toward the front end.

[0076] In this embodiment, the coil spring 16 also has the function of automatically retracting the tip holder 13 when the tip 14 is retracted (for example, by sliding an operating portion provided on the side of the writing instrument to release a locking mechanism that keeps the tip 14 protruding). In other words, the coil spring 16 functions as a so-called knock spring. (The operating load is approximately 50 gf to 300 gf (approximately 0.49 N to 2.94 N). For example, the operating load when not in use (FIG. 2) is 68 gf, the load at full stroke (FIG. 5) is 288 gf, and the operating load when writing (FIG. 6) is 227 gf. The spring constant is 0.23 N / mm.)

[0077] The retractable writing instrument 10 configured as above operates as follows.

[0078] When not in use, the tip 14 (writing element) of the retractable writing instrument 10 is in a retracted state as shown in Figures 1 and 2. At this time, the axial length of the coil spring 16 is 17 mm, the diameter of the annular member 15 is not reduced, and the small inner diameter cylindrical surface 15ia of the annular member 15 remains φ3.0 (>outer diameter of the tip 14).

[0079] When the tip is protruded (for example, by sliding the operating portion provided on the side surface of the writing instrument), the tip 14 (writing element) of the retractable writing instrument 10 reaches the state shown in FIG.

[0080] 4, the second collar portion 13c of the tip holder 13 is moved forward by the protruding operation of the tip 14. As a result, the annular member 15 is moved forward of the inner surface of the barrel 11 via the coil spring 16 and is further pressed against the front side of the inner surface, so that the first truncated cone outer surface 15b (contact surface) receives a load from the first truncated cone inner surface 11ib (guide surface), and the inner diameter of the annular member 15 is reduced due to the presence of the three slits 15s in the annular member 15.

[0081] The inner diameter when contracted corresponds to the outer diameter of the tip 14. That is, the minimum inner diameter when contracted (e.g., approximately 2.35 mm to 2.45 mm) allows the tip 14 (e.g., φ2.5 mm) to slide smoothly in the axial direction while providing effective anti-vibration for the tip 14 in the radial direction. Even if the outer diameter of the tip 14 is smaller (e.g., φ2.4 mm) or larger (e.g., φ2.6 mm) than the aforementioned φ2.5 mm, the same (same dimensions) annular member 15 can provide a similarly effective anti-vibration effect. That is, the retractable writing instrument 10 of this embodiment is compatible with different types of refills having different tip outer diameters in terms of anti-vibration effect. This improves user convenience.

[0082] In this embodiment, the second truncated cone outer surface 15d abuts against the second truncated cone inner surface 11id, thereby defining the forward movement limit of the annular member 15. That is, in this embodiment, the second truncated cone outer surface 15d of the annular member 15 and the second truncated cone inner surface 11id of the barrel 11 function as stopper elements that define the forward movement limit of the annular member 15. However, such a stopper element can be omitted.

[0083] Subsequently, when the tip protruding operation (for example, the sliding operation of the operating portion provided on the side surface of the writing instrument) is continued, the tip 14 (writing element) of the retractable writing instrument 10 reaches the state shown in FIG.

[0084] Then, when the tip extension operation is completed (for example, the sliding operation of the operating part provided on the side of the writing instrument is released), the tip 14 (writing body) of the retractable writing instrument 10 reaches the state shown in Figure 6. Normally, the position of the tip holder 13 is locked in the extended state shown in Figure 6, and the extended state of the tip 14 is maintained until the tip is subsequently retracted. At this time, the axial length of the coil spring 16 is 9.9 mm (compressed 10.1 mm), and the restoring force of the coil spring 16 maintains the annular member 15 in a contracted state. This allows the tip 14 to be held in a manner without any rattle (play).

[0085] Here, even if the stopper element that defines the forward movement limit of the annular member 15 functions, if the dimension of the small inner diameter cylindrical surface 15ia on the inner surface of the annular member 15 is sufficiently smaller than the outer diameter of the tip 14 (if the diameter difference is about 0.05 mm or more: see paragraph 0081), the tip holder 13 and the annular member 15 are connected to each other by the coil spring 16 so that they can move relative to each other, thereby ensuring that the tip 14 is effectively held without any rattling (play) without high-precision dimensional control over the degree of reduction in the inner diameter of the annular member 15, etc.

[0086] Thereafter, when the tip is retracted (for example, by re-sliding the operating part on the side of the writing instrument), a locking mechanism (not shown) is released, and the tip 14 (writing body) of the retractable writing instrument 10 returns to the state shown in Figure 5, and then, due to the action (restoring force) of the coil spring 16, it returns to the retracted state shown in Figure 2 via the state shown in Figure 4.

[0087] 2, the tip holder 13 is moved rearward, and the load that the first truncated cone outer surface 15b (contact surface) received from the first truncated cone inner surface 11ib (guide surface) disappears. As a result, the inner diameter of the annular member 15, which had been reduced, returns to its original state.

[0088] During the above-described process of the tip extension and retraction operation, the contact surface (first truncated cone outer surface 15b) of the annular member 15 and the guide surface (first truncated cone inner surface 11ib) of the barrel 11 are always in contact with each other.

[0089] As described above, according to the retractable writing instrument 10 of this embodiment, as the tip holder 13 moves toward the front end, the contact surface (first truncated cone outer surface 15b) of the annular member 15 receives a load from the guide surface (first truncated cone inner surface 11ib) of the barrel 11, and the presence of the slits 15s in the annular member 15 reduces the inner diameter of the annular member 15. This allows the barrel 11 and the annular member 15 to cooperate to hold the tip 14 without any rattle (play). Furthermore, according to the retractable writing instrument 10 of this embodiment, a stopper element functions to define the forward movement limit of the annular member 15, but since the dimensions of the small inner diameter cylindrical surface 15ia on the inner surface of the annular member 15 are sufficiently smaller than the outer diameter of the tip 14 (the diameter difference is approximately 0.05 mm or more: see paragraph 0081), and the tip holder 13 and the annular member 15 are connected to each other by the coil spring 16 so that they can move relative to each other, it is possible to ensure that the tip 14 is effectively held without any rattling (play) without requiring high-precision dimensional control over the degree of reduction in the inner diameter of the annular member 15, etc.

[0090] Furthermore, according to the retractable writing instrument 10 of this embodiment, three slits 15s as notches are arranged at equal intervals around the circumference of the annular member 15, and each slit 15s extends in the axial direction of the annular member 15, so that the inner diameter of the annular member 15 can be reduced in a balanced manner around the circumference.

[0091] Furthermore, since the contact surface (first truncated cone outer surface 15b) of the annular member 15 and the guide surface (first truncated cone inner surface 11ib) of the barrel 11 are corresponding truncated cone outer and inner surfaces, the contact surface of the annular member 15 can bear a load in a circumferentially balanced manner, and as a result, the diameter of the annular member 15 can be reduced in a circumferentially balanced manner. In this manner, the contact surface (first truncated cone outer surface 15b) of the annular member 15 and the guide surface (first truncated cone inner surface 11ib) of the barrel 11 are preferably tapered toward their front ends. The tapered contact surface has a convex curved surface that is rotationally symmetric about the axis, and the tapered guide surface may be a concave curved surface or a concave truncated cone surface that is rotationally symmetric about the axis and has a curvature that is gentler than the curvature of the convex curved surface.

[0092] Furthermore, by appropriately changing the number, size, shape, etc. of the slits 15s, it is possible to adjust the degree of elasticity (ease of diameter contraction) of the annular member 15. Furthermore, it is also possible to adjust the degree of elasticity (ease of diameter contraction) of the annular member 15 by changing the material and / or thickness of the annular member 15.

[0093] In this embodiment, an annular protrusion 11ih is provided on the inner peripheral surface of the barrel 11, which defines the rearward movement limit of the annular member 15. This effectively prevents the annular member 15 from moving excessively rearward (especially from falling off).

[0094] Furthermore, according to the retractable writing instrument 10 of this embodiment, the gripping portion (portion with the smallest inner diameter when the diameter is reduced) of the annular member 15 that grips the tip 14 is located forward of the contact surface (first truncated cone outer surface 15b) of the annular member 15 (there is no gripping portion radially inward of the contact surface). This allows the tip 14 to be gripped further forward, and the tip 14 can be gripped more effectively without any rattle (play).

[0095] Furthermore, according to the retractable writing instrument 10 of this embodiment, the rear end of the slit 15s is located forward of the coil spring 16. This allows the coil spring 16 and the annular member 15 to maintain a stable connection even when the annular member 15 is bent due to the presence of the slit 15s.

[0096] Furthermore, according to the retractable writing instrument 10 of this embodiment, the abutment surface (first truncated cone outer surface 15b) of the annular member 15 and the guide surface (first truncated cone inner surface 11ib) of the barrel 11 are always in abutment with each other. This prevents the abutment surface of the annular member 15 and the guide surface of the barrel 11 from repeatedly coming into and leaving abutment with each retraction of the tip 14, resulting in stable operation and a smooth operation feel for the user (no discomfort).

[0097] Furthermore, according to the retractable writing instrument 10 of this embodiment, the annular member 15 protrudes forward from the opening of the barrel 11. This allows the tip 14 to be held over a longer axial range, ensuring that the tip 14 can be held more effectively without any rattle (play). Furthermore, it is possible to visually appeal to the user that the retractable writing instrument 10 is equipped with a component (annular member 15) that provides an anti-vibration function. Furthermore, the external shape of the retractable writing instrument 10 near its front end when the tip 14 protrudes can be smoothly connected from the rear to the pen tip, which also has the effect of improving its aesthetic appearance.

[0098] Furthermore, according to the retractable writing instrument 10 of this embodiment, the amount (length) that the annular member 15 protrudes forward from the opening of the barrel 11 is smaller than the axial movable range of the annular member 15. As a result, even when the annular member 15 is pushed so as to be immersed in the opening of the barrel 11, the annular member 15 is still within the axial movable range, and therefore, the annular member 15 can be effectively prevented from undesirably falling off, etc.

[0099] Furthermore, in the retractable writing instrument 10 of this embodiment, it is preferable that a soft member (abrasion member) for a thermochromic writing instrument is provided at the knock operation portion for extending and retracting the tip 14 or at the rear of the barrel 11. When a conventional configuration is used in a thermochromic writing instrument, there is a risk that the vibration caused by rubbing the writing may cause the tip (or tip holder) to rattle and generate noise, but this risk does not occur with the configuration of this embodiment. Therefore, it is also recommended that the configuration of this embodiment be used in a thermochromic writing instrument.

[0100] Second Embodiment FIG. 7 is a schematic vertical cross-sectional view of the retractable writing instrument 20 according to the second embodiment of the present invention, showing a state in which the tip 24 (writing element) is not protruding.

[0101] 8(a) is an oblique view of the annular member 25 of the retractable writing instrument 20 of FIG. 7, FIG. 8(b) is a plan view of the annular member 25 of FIG. 8(a), FIG. 8(c) is a side view of the annular member 25 of FIG. 8(a), FIG. 8(d) is a bottom view of the annular member 25 of FIG. 8(a), FIG. 8(e) is a cross-sectional view along line AA of FIG. 8(b), FIG. 8(f) is a front view (viewed from the tip side) of the annular member 25 of FIG. 8(a), and FIG. 8(g) is a back view of the annular member 25 of FIG. 8(a).

[0102] As shown in Figures 7 and 8, the retractable writing instrument 20 of the second embodiment differs from the retractable writing instrument 10 of the first embodiment in the shape of the annular member 25 and the shape of the inner surface of the front portion 21m of the barrel 21.

[0103] Similar to the retractable writing instrument 10 of the first embodiment, a tip holder 23 that is movable in the axial direction of the barrel 21 is housed inside the barrel 21. A tip 24, which is a writing element, is fixed to the front end of the tip holder 23. The tip 24 can be protruded and retracted from the opening of the barrel 21 as the tip holder 23 moves.

[0104] 7, the tip holder 23 has, in this order from the base end to the tip end, a base end portion 23a, a first collar portion 23b, and a second collar portion 23c. In this embodiment, the base end portion 23a and the first collar portion 23b are both cylindrical, and the second collar portion 23c is a frustoconical portion in this embodiment, with the cross-sectional diameters of the base end portion 23a > first collar portion 23b > second collar portion 23c.

[0105] 7, in this embodiment, an annular member 25 that is movable in the axial direction of the barrel 21 relative to the barrel 21 is loosely fitted around the inner periphery of the opening of the barrel 21. The front end of the annular member 25 is located further forward than the front end of the barrel 21. The rear side of the annular member 25 has an expanded outer diameter and an expanded inner diameter, and covers the periphery of the tip 24 (φ2.5) without contacting it.

[0106] The annular member 25 is fixed to the front end of a coil spring 26 (an example of an elastic member). The coil spring 26 surrounds the second collar portion 23c of the tip holder 23 and the tip 24 in a loose fit (with a gap), and the rear end of the coil spring 26 is constantly pressed by the base end portion 23a of the tip holder 23 (it is not fixed). As a result, the coil spring 26 connects the tip holder 23 and the annular member 25 so that they can move relative to each other. As the tip holder 23 moves and the coil spring 26 expands and contracts, the annular member 25 can move in the axial direction of the barrel 21 relative to the barrel 21.

[0107] The annular member 25 is made of resin (for example, polyacetal, polypropylene, or polyethylene) or metal (for example, brass).

[0108] As shown in Figures 8(a) to 8(g), the outer peripheral surface of the annular member 25 is provided with, in this order from the front side, a small outer diameter cylindrical surface 25a (φ3.6 mm, axial length 1.6 mm), a first truncated conical outer surface 25b (axial length 1 mm) as a tapered abutment surface, a medium outer diameter cylindrical surface 25c (φ4.8 mm, axial length 1.6 mm), a second truncated conical outer surface 25d (axial length 1.2 mm) as a tapered abutment surface, a first large outer diameter cylindrical surface 25e (φ6.2 mm, axial length 0.8 mm), a second large outer diameter cylindrical surface 25f (φ5.8 mm, axial length 0.6 mm), and a coil spring fitting cylindrical surface 25g (φ4.75 mm, axial length 1 mm). Referring to FIG. 7, in this embodiment, the front end of the coil spring 26 is fixed (fitted and fixed) onto the coil spring fitting cylindrical surface 25g.

[0109] As shown in Figure 8(e), the inner peripheral surface of the annular member 25 is provided with, in that order from the front side, a small inner diameter cylindrical surface 25ia (φ2.6 mm, axial length 1.9 mm), a first truncated conical inner surface 25ib (axial length 0.9 mm), and a large inner diameter cylindrical surface 25ic (φ3.6 mm, axial length 5.6 mm).

[0110] In addition, three slits 25s are provided as cutouts in the annular member 25 of this embodiment. As shown in Figures 8(a) to 8(g), the three slits 25s are arranged at equal intervals (every 120°) around the circumference of the annular member 25. Each of the three slits 25s has a width of 1 mm and extends in the axial direction of the annular member 25 from the front end to approximately the rear end of the second frusto-conical outer surface 15d (maximum axial length of 5.3 mm).

[0111] As a result, when a load is applied to the first truncated cone outer surface 25b (contact surface), the inner diameter of the annular member 25 flexibly contracts, and when the load is released, the inner diameter of the annular member 25 elastically returns to its original state.

[0112] On the other hand, the inner surface near the opening of the barrel 21 is provided with, in that order from the front side, a small inner diameter cylindrical surface 21ia (φ3.7 mm, axial length 1.2 mm), a first truncated conical inner surface 21ib (axial length 1.1 mm) as a tapered guide surface, a medium inner diameter cylindrical surface 21ic (φ4.95 mm, axial length 1.3 mm), a second truncated conical inner surface 21id (axial length 1.2 mm) as a tapered guide surface, a large inner diameter cylindrical surface 21ie (φ6.3 mm, axial length 1.5 mm), and an annular protrusion 21if (minimum aperture diameter φ6 mm) as a regulating element.

[0113] As a result, the first truncated cone outer surface 25b (contact surface) receives a load from the first truncated cone inner surface 21ib (guide surface) as the tip holder 13 moves toward the front end side.

[0114] Coil spring 26 in this embodiment also has the function of automatically retracting tip holder 23 when tip 24 is retracted (for example, by sliding an operating portion provided on the side of the writing instrument to release a locking mechanism that keeps tip 24 protruding). In other words, coil spring 26 functions as a so-called knock spring. (The operating load is approximately 50 gf to 300 gf (approximately 0.49 N to 2.94 N). For example, the operating load when not in use (FIG. 7) is 67 gf, the load at full stroke (not shown) is 285 gf, and the operating load when writing (not shown) is 225 gf. The spring constant is 0.23 N / mm.)

[0115] The retractable writing instrument 20 configured as above operates as follows.

[0116] When not in use, the tip 24 (writing element) of the retractable writing instrument 20 is in a retracted state as shown in Figure 7. At this time, the axial length of the coil spring 26 is 17 mm, the diameter of the annular member 25 is not reduced, and the small inner diameter cylindrical surface 25ia of the annular member 25 remains φ2.6 (>outer diameter of the tip 24).

[0117] When the tip is protruded (for example, by sliding the operating part provided on the side of the writing instrument), the annular member 25 is moved to the front side of the inner surface of the barrel 21 via the coil spring 26 and is further pressed against the front side of the inner surface, so that the first truncated cone outer surface 25b (contact surface) receives a load from the first truncated cone inner surface 21ib (guide surface), and the inner diameter of the annular member 25 is reduced due to the presence of the three slits 25s in the annular member 25.

[0118] The inner diameter when contracted corresponds to the outer diameter of the tip 24. That is, the minimum inner diameter when contracted (e.g., approximately 2.35 mm to 2.45 mm) allows the tip 24 (e.g., φ2.5 mm) to slide smoothly in the axial direction while providing effective anti-vibration for the tip 24 in the radial direction. Furthermore, even if the outer diameter of the tip 24 is smaller (e.g., φ2.4 mm) or larger (e.g., φ2.6 mm) than the aforementioned φ2.5 mm, the same (same dimensions) annular member 25 can provide a similarly effective anti-vibration effect. That is, the retractable writing instrument 20 of this embodiment is compatible with different types of refills having different tip outer diameters in terms of anti-vibration effect. This improves user convenience.

[0119] When the tip extension operation is completed (for example, when the sliding operation of the operating part provided on the side of the writing instrument is released), the position of tip holder 23 is locked, and the tip 24 remains extended until the tip is subsequently retracted. At this time, the axial length of coil spring 26 is 9.9 mm (compressed 10.1 mm), and the restoring force of coil spring 26 maintains annular member 25 in a contracted state. This allows tip 24 to be held without any rattle (play).

[0120] Here, since the chip holder 23 and the annular member 25 are connected by the coil spring 26 so that they can move relative to each other, it is possible to ensure that the chip 24 is effectively held without any rattle (play) even without high-precision dimensional control over the degree of reduction in the inner diameter of the annular member 25.

[0121] Thereafter, when the tip is retracted (for example, when the operating part provided on the side of the writing implement is slid again), for example, a locking mechanism (not shown) is released, and the action (restoring force) of the coil spring 26 causes the tip to return to the retracted state shown in FIG.

[0122] 7, the tip holder 23 is moved rearward, and the load that the first truncated cone outer surface 25b (contact surface) received from the first truncated cone inner surface 21ib and the second truncated cone inner surface 21id (guide surfaces) disappears, and the inner diameter of the annular member 25, which had been reduced, returns to its original state.

[0123] During the above-described process of the tip extension and retraction operation, the contact surface (first truncated cone outer surface 25b) of the annular member 25 and the guide surface (first truncated cone inner surface 21ib) of the barrel 21 are always in contact with each other.

[0124] As described above, in the retractable writing instrument 20 of this embodiment, as the tip holder 23 moves toward the front end, the contact surface (first truncated cone outer surface 25b) of the annular member 25 receives a load from the guide surface (first truncated cone inner surface 21ib) of the barrel 21, and the presence of the slits 25s in the annular member 25 causes the inner diameter of the annular member 25 to decrease. This allows the barrel 21 and the annular member 25 to cooperate to hold the tip 24 without any play (play). Furthermore, because the tip holder 23 and the annular member 25 are connected by the coil spring 26 so that they can move relative to each other, it is possible to ensure that the tip 24 is effectively held without any play (play), even without highly precise dimensional control over the degree of reduction in the inner diameter of the annular member 25.

[0125] Furthermore, in the retractable writing instrument 20 of this embodiment, three slits 25s as notches are arranged at equal intervals around the circumference of the annular member 25, and each slit 25s extends in the axial direction of the annular member 25, so that the inner diameter of the annular member 25 can be reduced in a balanced manner around the circumference.

[0126] Furthermore, since the abutment surface (first truncated cone outer surface 25b) of the annular member 25 and the guide surface (first truncated cone inner surface 21ib) of the barrel 21 are corresponding truncated cone outer surface and truncated cone inner surface, the abutment surface of the annular member 25 can receive a load in a circumferentially balanced manner, and as a result, the annular member 25 can be reduced in diameter in a circumferentially balanced manner.

[0127] Furthermore, by appropriately changing the number, size, shape, etc. of the slits 25s, it is possible to adjust the degree of elasticity (ease of diameter contraction) of the annular member 25. Furthermore, by changing the material and / or thickness of the annular member 25, it is possible to adjust the degree of elasticity (ease of diameter contraction) of the annular member 25.

[0128] In this embodiment, an annular protrusion 21if is provided on the inner peripheral surface of the barrel 21, and defines the rearward movement limit of the annular member 25. This effectively prevents the annular member 25 from excessively moving rearward (especially from falling off).

[0129] Furthermore, in the retractable writing instrument 20 of this embodiment, the gripping portion (portion with the smallest inner diameter when the diameter is reduced) that grips the tip 24 in the annular member 25 is located forward of the contact surface (first truncated cone outer surface 25b) of the annular member 25 (there is no gripping portion radially inward of the contact surface). This allows the tip 24 to be gripped further forward, and the tip 24 can be gripped more effectively without any rattle (play).

[0130] Furthermore, in the retractable writing instrument 20 of this embodiment, the rear end of the slit 25s is located forward of the coil spring 26. This allows the coil spring 26 and the annular member 25 to maintain a stable connection even when the annular member 25 is bent due to the presence of the slit 25s.

[0131] Furthermore, in the retractable writing instrument 20 of this embodiment, the abutment surface (first truncated cone outer surface 25b) of the annular member 25 and the guide surface (first truncated cone inner surface 21ib) of the barrel 21 are always in abutment with each other. This prevents the abutment surface of the annular member 25 and the guide surface of the barrel 21 from repeatedly coming into and out of abutment with each retraction operation of the tip 24, resulting in stable operation and a smooth operation feel for the user (no discomfort).

[0132] Furthermore, in the retractable writing instrument 20 of this embodiment, the annular member 25 also protrudes forward from the opening of the barrel 21. This allows the tip 24 to be held over a longer axial range, ensuring that the tip 24 can be held more effectively without any rattle (play). Furthermore, it is possible to visually appeal to the user that the retractable writing instrument 20 is equipped with a component (annular member 25) that provides an anti-vibration function. Furthermore, the external shape of the retractable writing instrument 20 near its front end when the tip 24 protrudes can be smoothly connected from the rear to the pen tip, which also has the effect of improving its aesthetic appearance.

[0133] Furthermore, with the retractable writing instrument 20 of this embodiment, the amount (length) by which the annular member 25 protrudes forward from the opening of the barrel 21 is smaller than the axial movable range of the annular member 25. As a result, even when the annular member 25 is pushed so as to be immersed in the opening of the barrel 21, the annular member 25 is still within the axial movable range, and therefore, the annular member 25 can be effectively prevented from undesirably falling off, etc.

[0134] Furthermore, in the retractable writing instrument 20 of this embodiment, it is preferable that a soft member (abrasion member) for a thermochromic writing instrument be provided at the knock operation portion for extending and retracting the tip 24 or at the rear of the barrel 21. When a conventional configuration is used in a thermochromic writing instrument, there is a risk that the vibrations caused by rubbing writing can cause the tip (or tip holder) to rattle and generate noise, but this risk does not occur with the configuration of this embodiment. Therefore, it is also recommended that the configuration of this embodiment be used in a thermochromic writing instrument.

[0135] <Third embodiment> FIG. 9 is a schematic vertical cross-sectional view of a retractable writing instrument 20' according to a third embodiment of the present invention, showing a state in which the tip 24 (writing element) is not protruding.

[0136] 10(a) is a perspective view of the annular member 25' of the retractable writing instrument 20' of FIG. 9, FIG. 10(b) is a plan view of the annular member 25' of FIG. 10(a), FIG. 10(c) is a side view of the annular member 25' of FIG. 10(a), FIG. 10(d) is a bottom view of the annular member 25' of FIG. 10(a), FIG. 10(e) is a cross-sectional view along line AA of FIG. 10(c), FIG. 10(f) is a front view (viewed from the tip side) of the annular member 25' of FIG. 10(a), and FIG. 10(g) is a back view of the annular member 25' of FIG. 10(a).

[0137] As shown in Figures 9 and 10, the retractable writing instrument 20' of the third embodiment is slightly different from the retractable writing instrument 20 of the second embodiment in the shape of the annular member 25' and the shape of the inner surface of the front portion 21m' of the barrel 21'.

[0138] Specifically, as shown in Figures 10(a) to 10(g), the axial length of the small outer diameter cylindrical surface 25a' of the annular member 25' is slightly shorter (φ3.6 mm, axial length 1.3 mm), and a flange portion 25j (φ4.4 mm, axial length 0.8 mm) is provided further forward, and the axial length of the small inner diameter cylindrical surface 25ia' is slightly longer (φ2.6 mm, axial length 2.38 mm).

[0139] In this embodiment, the flange portion 25j functions as a stopper element that defines the rearward movement limit of the annular member 25'. For this reason, no annular protrusion is provided on the inner surface of the barrel 21'.

[0140] The retractable writing instrument 20' of the third embodiment can also provide substantially the same effects as the retractable writing instrument 20 of the second embodiment.

[0141] (Additional information about refills) The retractable writing instrument 10 of this embodiment is a writing instrument comprising a barrel 11, a refill (writing body) housed within the barrel 11, and a retractable mechanism that allows the tip 14 of the refill to be freely retracted and retracted from the opening of the barrel 11.

[0142] An example of a refill will be further explained with reference to Figures 25 to 27. Referring to Figure 25, the refill 6 comprises, for example, a pen tip (chip) 61, an ink reservoir 62 into whose front end opening the pen tip 61 is press-fitted and fixed, thermochromic ink filled in the ink reservoir 62, a follower (e.g., a high-viscosity fluid) filled adjacent to the rear end of the thermochromic ink and moving forward as the thermochromic ink is consumed, and a tail plug 63 attached to the rear end opening of the ink reservoir 62. The tail plug 63 has an air hole 63a that opens toward the rear end. The air hole 63a allows ventilation between the inside and outside of the ink reservoir 62.

[0143] The pen tip 61 may consist of, for example, a metal ballpoint pen tip that rotatably holds a ball at its front end, or may consist of a combination of such a ballpoint pen tip and a synthetic resin pen tip holder that holds the rear outer surface of the ballpoint pen tip. A spring is housed inside the pen tip 61 to press the ball at the front end forward. The spring may be, for example, a compression coil spring with a rod attached to the front end, the front end of which contacts the rear surface of the ball. When not writing, the forward bias of the spring keeps the ball in close contact with the inner surface of the inward-facing front edge of the ballpoint pen tip. This prevents ink from leaking from the front end of the pen tip 61 and ink from evaporating.

[0144] (Additional information about the rear end of the barrel 11) The barrel 11 of this embodiment comprises, for example, a tapered cylindrical front barrel 3 (see Figure 28), a cylindrical intermediate barrel 4 (see Figure 29) connected to the rear end of the front barrel 3, and a cylindrical rear barrel 5 (see Figure 30) connected to the rear end of the intermediate barrel 4.

[0145] 30 , an attachment hole 52 may be formed in the rear end of the rear axle 5 in the front-to-rear direction, and a friction portion 53 made of an elastic material may be press-fitted into the attachment hole 52. This allows the friction portion 53 to be fixed to the outer surface of the rear end of the rear axle 5. Also, an inward protrusion 54 may be formed integrally with the inner surface of the rear axle 5.

[0146] The elastic material constituting the friction portion 53 is preferably, for example, an elastic synthetic resin (rubber, elastomer), such as silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butylene-styrene copolymer), fluorine-based resin, chloroprene resin, nitrile resin, polyester-based resin, ethylene propylene diene rubber (EPDM), or a mixture of two or more types of rubber elastic materials, and a mixture of a rubber elastic material and a synthetic resin.

[0147] The elastic synthetic resin that makes up friction portion 53 is preferably made of a low-wear elastic material that produces almost no wear debris (eraser dust) during friction, rather than a high-wear elastic material (such as an eraser). Friction portion 53 can be provided on the outer surface of the rear end of barrel 11 in a variety of ways. For example, friction portion 53 made of an elastic material can be provided on the outer surface of the rear end of barrel 11 or the outer surface of the rear end of rear axle 5 by press-fitting, engaging, screwing, fitting, bonding, two-color molding, or the like. Alternatively, the entire barrel 11 or the entire rear axle 5 can be integrally formed from an elastic material.

[0148] (Additional information about knock member 8) 31 , a clip 83 extending in the front-rear direction can be fixed to the knock member 8. A ball portion can be protruded from the back surface of the clip 83. The knock member 8 includes, for example, a base portion 81 to which the rear end portion of the clip 83 is fixed, and a cylindrical shaft portion 82 that is integrally connected to the base portion 81 and extends forward from the base portion 81.

[0149] The knock member 8 is obtained by molding, for example, a synthetic resin (for example, polycarbonate resin). The clip 83 is obtained by molding, for example, a synthetic resin (for example, polycarbonate resin) or a metal material (for example, stainless steel). The knock member 8 and the clip 83 may be integrally formed by synthetic resin.

[0150] As shown in FIG. 31, the front end of the shaft portion 82 may be integrally formed with cam teeth 82a that engage with the rear end of the ridge 71 of the retractable rotary member 7 (see FIGS. 32 to 35).

[0151] To assemble the knock member 8, the base portion 81 of the knock member 8 is inserted into the first elongated hole 41 of the intermediate shaft 4 from the rear end (open portion) of the first elongated hole 41, and the shaft portion 82 of the knock member 8 is inserted into the intermediate shaft 4. Thereafter, while fitting the inner surface of the rear shaft 5 with the outer surface of the reduced diameter portion of the intermediate shaft 4, the base portion 81 of the knock member 8 is inserted into the second elongated hole 51 of the rear shaft 5 from the front end (open portion) of the second elongated hole 51. As a result, the intermediate shaft 4 and the rear axle 5 are connected (the outward projection 44 of the intermediate shaft 4 and the inward projection 54 of the rear axle 5 are engaged to climb over each other), and the first elongated hole 41 and the second elongated hole 51 form a slide hole 21 that extends in the front-to-rear direction, with the knock member 8 protruding radially outward from the slide hole 21. The knock member 8 is slidable in the front-to-rear direction along the slide hole 21 (is slidable in the front-to-rear direction).

[0152] Rear shaft 5, which has friction portion 53 fixed to its rear end, is connected to the rear end of intermediate shaft 4, so that friction portion 53 is always fixed to the rear end of barrel 11. Furthermore, because front shaft 3 and intermediate shaft 4 are detachably connected by screwing, refill 6 can be replaced at any time.

[0153] (Additional information about the haunting mechanism) The retractable mechanism of this embodiment is a side-slide type retractable mechanism that uses a rotary cam mechanism, and is composed of the aforementioned knock member 8, the retractable rotating member 7 that moves back and forth to protrude or retract the nib 61 from the opening of the barrel 11 each time the knock member 8 is moved forward, and rotates the refill 6 (and therefore the nib 61), the aforementioned cam portion 43 that is provided within the barrel 11 and can engage or disengage with the retractable rotating member 7 depending on the position of the knock member 8, and a knock spring 12 (e.g., a compression coil spring) that is provided within the barrel 11 and urges the refill 6 backward.

[0154] The retraction mechanism of this embodiment is a double knock type in which the knock member 8 is pressed forward (slid forward) for both the pen tip protruding operation and the pen tip retracting operation.

[0155] (Additional information about thermochromic ink) In this embodiment, the thermochromic ink is preferably a reversible thermochromic ink. The reversible thermochromic ink may be of various types, either alone or in combination, such as a thermal decolorization type that is decolorized from a colored state by heating, a color memory retention type that alternately retains the colored state or the decolorized state within a specific temperature range, or a thermal color development type that develops color from a decolorized state by heating and returns to the decolorized state by cooling from the colored state.

[0156] The coloring material contained in the reversible thermochromic ink is preferably, for example, a reversible thermochromic pigment in which a reversible thermochromic composition containing at least the three essential components of (i) an electron-donating color-forming organic compound, (ii) an electron-accepting compound, and (iii) a reaction medium that determines the temperature at which the reaction (coloring reaction) in which the two compounds chemically bond with each other occurs is encapsulated in microcapsules.

[0157] (Additional information about the rotation of Refill 6) As described above, in this embodiment, each time the knock member 8 is moved forward, it moves back and forth to protrude or retract the nib 61 from the opening of the barrel 11, and the refill 6 (and therefore the nib 61) is rotated. Writing instruments in which the nib 61 rotates in this way are popular on the market because they can even out wear on the nib 61.

[0158] Figure 36 is a schematic diagram illustrating the principle of the rotation cam mechanism. Referring to Figure 36, when the knock member 8 is pressed (slid) forward from the pen tip retracted state (see Figure 36(a)) against the rearward bias of the spring (not shown), the protrusion 71 of the retractable rotation member 7 that has been engaged with the cam tooth 82a is pressed forward via the cam tooth 82a at the front end of the shaft portion 82 of the knock member 8. The protrusion 71 of the retractable rotation member 7 moves forward along the cam groove 43b.

[0159] When the protrusion 71 of the retractable rotary member 7 is moved forward, the retractable rotary member 7 presses the refill 6 forward via the abutment between the abutment portion 73 and the protrusion 63b of the tail plug 63. This causes the pen tip 61 to protrude outward from the opening of the barrel 11.

[0160] When the knock member 8 is in the deepest position of the knock operation, the rear end of the protrusion 71 moves out of the cam groove 43b of the cam portion 43 and drops into the valley of the cam tooth 82a of the knock member 8, causing the protruding and retracting rotating member 7 to rotate slightly in the circumferential direction (see Figure 36(b)).

[0161] Subsequently, when the knock member 8 is returned to its original position by the backward urging of the spring, the rear end of the ridge 71 moves so as to drop into the valley of the cam tooth 43a of the cam portion 43, and accordingly the retractable rotating member 7 further rotates in the circumferential direction (see FIG. 36(c)). In addition, the rear end of the ridge 71 remains in the position of the valley of the cam tooth 43a of the cam portion 43, so the pen tip protrudes.

[0162] Next, when the knock member 8 is pressed (slid) forward from the pen tip protruding state (see Figure 36c), the cam teeth 82a at the front end of the shaft 82 of the knock member 8 again engage the rear end of the protrusion 71 of the retractable rotating member 7 and press it forward.

[0163] When the knock member 8 is in the deepest position of the knock operation, the rear end of the ridge 71 moves over the crest (tooth) of the cam tooth 43a of the cam portion 43 and drops into the valley of the cam tooth 82a of the knock member 8, causing the retractable rotary member 7 to rotate slightly in the circumferential direction (see Figure 36(d)). Subsequently, when the knock member 8 is returned to its original position by the rearward bias of the spring, the ridge 71 is introduced into the cam groove 43b, and the pen tip retracted state is maintained (see Figure 36(a)).

[0164] 37 and 38 show the state in which the protruding piece 63b of the tail plug 63 and the abutting portion 73 of the retractable rotary member 7 are in contact with each other.

[0165] An abutment portion 73 on the front surface of the retractable rotation member 7 abuts against the protruding piece 63b of the tail plug 63 at the rear end of the refill 6, and multiple protrusions 72 on the front surface of the retractable rotation member 7 are inserted into the gaps 63c between the protruding pieces 63b of the tail plug 63 at the rear end of the refill 6, engaging them in the circumferential direction. As a result, as the retractable rotation member 7 rotates in the circumferential direction, the refill 6 also rotates in the circumferential direction.

[0166] As described above, in this embodiment, the abutment portion 73 on the front surface of the retractable rotatable member 7 rotates the tail plug 63 at the rear end of the refill 6. However, it is also possible to adopt a configuration in which the retractable rotatable member 7 transmits the rotational force to another part of the refill 6. For example, it is also possible to adopt a configuration in which the tail plug 63 is not included, and multiple protrusions are integrally formed at the rear end of the refill 6.

[0167] (Additional information regarding the rotation of the annular members 15, 25, and 25') When the refill 6 is rotated relative to the barrel tubes 11, 21 by pressing the knock member 8, the annular members 15, 25, 25' connected to the refill 6 via the coil springs 16, 26 are also rotated relative to the barrel tubes 11, 21.

[0168] At this time, the front ends of the coil springs 16, 26 are fixed to the annular members 15, 25, 25'. As a result, the front ends of the coil springs 16, 26 do not slide on the inner surfaces of the annular members 15, 25, 25', and there is no risk of the front ends damaging the annular members 15, 25, 25'. In addition, the annular members 15, 25, 25' connected to the refill 6 via the coil springs 16, 26 also rotate relative to the barrels 11, 21, allowing the refill 6 and the coil springs 16, 26 to rotate together. As a result, the rear ends of the coil springs 16, 26 do not slide on the tip holders 13, 23, and there is no risk of the rear ends damaging the tip holders 13, 23. Furthermore, since the refill 6, the annular members 15, 25, 25', and the coil springs 16, 26 rotate together, there is no risk of impeding the smooth rotation of the refill 6 (and thus the pressing operation of the knock member 8). Furthermore, since the rotation of the annular members 15, 25, 25' is visible, it is possible to provide visual interest to the user.

[0169] (Rotation direction of refill 6 and winding direction of coil springs 16 and 26) In the embodiment described above, the rotation direction of the refill 6 is clockwise when viewed from the rear end, and the winding direction of the coil springs 16, 26 is counterclockwise (so-called left-handed springs) (extending counterclockwise from the start of winding: see Figure 2).

[0170] However, if the rotation direction of the refill 6 and the winding direction of the coil springs 16, 26 are aligned, the tip holders 13, 23 (their coil spring abutment portions) will be oriented to push the rear ends of the coil springs 16, 26 when the refill 6 rotates, which will result in a strong connection between the tip holders 13, 23 and the coil springs 16, 26 (for example, the two will be hooked together), making it easier for the coil springs 16, 26 to transmit the rotational force of the refill 6 to the annular members 15, 25, 25', which is preferable.

[0171] FIG. 39 is a view corresponding to FIG. 2, showing an embodiment in which the winding direction of the coil spring 16 is reversed.

[0172] Here, it is further preferable that the coil spring abutment portions of the chip holders 13, 23 are provided with an uneven shape or the like to make the connection with the rear ends of the coil springs 16, 26 stronger.

[0173] (R chamfering of the inner peripheral surfaces of the annular members 15, 25, and 25') As described with reference to FIG. 3(e), the inner peripheral surface of the annular member 15 is provided with, in order from the front, a small inner diameter cylindrical surface 15ia, a first truncated conical inner surface 15ib, a medium inner diameter cylindrical surface 15ic, a second truncated conical inner surface 15id, a four-sided chamfered portion 15ie, a large inner diameter cylindrical surface 15if, and a third truncated conical inner surface 15ig. A R-chamfer may be provided at the connection region (boundary) between the small inner diameter cylindrical surface 15ia and the first truncated conical inner surface 15ib. This prevents the tip 14 from getting caught when it is inserted into the small inner diameter cylindrical surface 15ia, allowing for smoother insertion.

[0174] 8(e), the inner peripheral surface of the annular member 25 is provided with, in order from the front, a small inner diameter cylindrical surface 25ia, a first truncated conical inner surface 25ib, and a large inner diameter cylindrical surface 25ic, but a rounded chamfer may be provided at the connection region (boundary) between the small inner diameter cylindrical surface 25ia and the first truncated conical inner surface 25ib. In this case, when the tip 24 is inserted into the small inner diameter cylindrical surface 25ia, there is no catching, and therefore smoother insertion can be achieved.

[0175] 10(e), the inner peripheral surface of the annular member 25' is provided with, from the front side, a small inner diameter cylindrical surface 25ia', a first truncated conical inner surface 25ib, and a large inner diameter cylindrical surface 25ic, in that order, but a rounded chamfer may be provided at the connection region (boundary) between the small inner diameter cylindrical surface 25ia' and the first truncated conical inner surface 25ib. In this case, when the tip 24 is inserted into the small inner diameter cylindrical surface 25ia', there is no catching, and therefore smoother insertion can be achieved.

[0176] Furthermore, as shown in FIG. 40, instead of providing the first truncated conical inner surface 15ib of FIG. 3(e), an embodiment may be adopted in which the small inner diameter cylindrical surface 15ia' and the medium inner diameter cylindrical surface 15ic' are connected by a rounded chamfered portion 15ib' (the first truncated conical inner surface 15ib is replaced by the chamfered portion 15ib'). In this case, too, when the tip 14 is inserted into the small inner diameter cylindrical surface 15ia', there is no catching, so smoother insertion can be achieved. In the modified example shown in FIG. 40, the inner peripheral surface of the annular member 15' is provided with, from the front side, the small inner diameter cylindrical surface 15ia', the chamfered portion 15ib', the medium inner diameter cylindrical surface 15ic', the second truncated conical inner surface 15id', the four-sided chamfered portion 15ie', the large inner diameter cylindrical surface 15if', and the third truncated conical inner surface 15ig', in that order. Three slits 15s' are provided as notches.

[0177] Similarly, although not shown, instead of providing the first truncated conical inner surface 25ib shown in Fig. 8(e), a configuration may be adopted in which the small inner diameter cylindrical surface 25ia and the medium inner diameter cylindrical surface 25ic are connected by a rounded chamfer (the first truncated conical inner surface 25ib is replaced by the chamfered portion). In this case, too, the tip 24 does not get caught when being inserted into the small inner diameter cylindrical surface 25ia, allowing for smoother insertion.

[0178] Similarly, although not shown, instead of providing the first truncated conical inner surface 25ib shown in Fig. 10(e), a configuration may be adopted in which the small inner diameter cylindrical surface 25ia' and the medium inner diameter cylindrical surface 25ic are connected by a rounded chamfer (the first truncated conical inner surface 25ib is replaced by the chamfer). In this case, too, the tip 24 does not get caught when being inserted into the small inner diameter cylindrical surface 25ia', allowing for smoother insertion.

[0179] (Other aspects of the notch) In the embodiments described above, the slits 15s, 15s', and 25s are provided as the cutouts. That is, the cutouts are formed to penetrate from the inner periphery to the outer periphery of the annular members 15, 15', 25, and 25'.

[0180] However, the notch is not limited to such a configuration, and may be formed as a portion thinner than the surrounding area (a configuration in which a portion of the thickness is cut away). For example, a configuration in which thin portions remain at the portions of slits 15s, 15s', and 25s may be adopted.

[0181] Figure 41(a) is a perspective view of such a modified annular member 15", Figure 41(b) is a plan view of the annular member 15" of Figure 41(a), Figure 41(c) is a side view of the annular member 15" of Figure 41(a), Figure 41(d) is a bottom view of the annular member 15" of Figure 41(a), Figure 41(e) is a cross-sectional view along line AA of Figure 41(c), Figure 41(f) is a front view (view from the tip side) of the annular member 15" of Figure 41(a), and Figure 41(g) is a back view of the annular member 15" of Figure 41(a).

[0182] As shown in Figures 41(a) to 41(g), the outer peripheral surface of the annular member 15" is provided with, in this order from the front side, a small outer diameter cylindrical surface 15a", a first truncated conical outer surface 15b" as a tapered abutment surface, a medium outer diameter cylindrical surface 15c", a second truncated conical outer surface 15d" as a tapered abutment surface, a first large outer diameter cylindrical surface 15e", a third truncated conical outer surface 15f" as a tapered abutment surface, and a second large outer diameter cylindrical surface 15g".

[0183] The annular member 15" of this modified example is provided with three thin-walled portions 15t" as cutouts. As shown in Figures 41(a) to 41(g), the three thin-walled portions 15t" are arranged at positions corresponding to the three slits 15s in Figures 3(a) to 3(g), i.e., at equal intervals (every 120°) around the circumference of the annular member 15". Each of the three thin-walled portions 15t" is 0.8 mm wide and 0.2 mm thick, and extends from the front end to approximately the center of the second frusto-conical outer surface 15d" in the axial direction of the annular member 15" (maximum axial length 5.5 mm).

[0184] Even in such a modified example, when a load is applied to the first frusto-conical outer surface 15b'' (contact surface), the inner diameter of the annular member 15'' can flexibly contract, and when the load is released, the inner diameter of the annular member 15'' can elastically return to its original state. [Explanation of symbols]

[0185] 10 Removable writing instrument 11 Shaft cylinder 11ia Small inner diameter cylindrical surface 11ib First truncated cone inner surface 11ic Medium inner diameter cylindrical surface 11id Second truncated cone inner surface 11ie First large bore cylindrical surface 11if Third truncated cone inner surface 11ig Second large bore cylindrical surface 11ih Annular protrusion 11m front part 11r rear part 13 Chip holder 13a Proximal end 13b 1st Color Section 13c 2nd Color Section 14 chips 15 Annular member 15a Small outer diameter cylindrical surface 15b First truncated cone outer surface 15c Medium outer diameter cylindrical surface 15d Second truncated cone outer surface 15e First large outer diameter cylindrical surface 15f Third truncated cone outer surface 15g Second large outer diameter cylindrical surface 15ia small inner diameter cylindrical surface 15ib First truncated cone inner surface 15ic Medium inner diameter cylindrical surface 15id Second truncated cone inner surface 15ie Four-sided sweeping section 15if large inner diameter cylindrical surface 15ig third truncated cone inner surface 15s slit 15' Circular Member 15ia' small inner diameter cylindrical surface 15ib' chamfer 15ic' Medium Inner Diameter Cylindrical Surface 15id' Second truncated cone inner surface 15ie' Four-sided sweep 15if' large inner diameter cylindrical surface 15ig' Third truncated cone inner surface 15s' slit 15" annular member 15a” small outer diameter cylindrical surface 15b" First truncated cone outer surface 15c" medium outer diameter cylindrical surface 15d" Second truncated cone outer surface 15e" First large outer diameter cylindrical surface 15f” 3rd truncated cone outer surface 15g" Second large outer diameter cylindrical surface 15t thin section 16 Coil spring 20 Removable writing instrument 20' retractable writing instrument 21 Shaft cylinder 21' barrel 21ia Small inner diameter cylindrical surface 21ib First truncated cone inner surface 21ic Medium inner diameter cylindrical surface 21id Second truncated cone inner surface 21ie Large inner diameter cylindrical surface 21if Annular protrusion 21m front part 21m' front part 23 Chip holder 23a Proximal end 23b 1st Color Section 23c 2nd Color Section 24 chips 25 Annular member 25' Circular Member 25a Small outer diameter cylindrical surface 25a' Small outer diameter cylindrical surface 25b First truncated cone outer surface 25c Medium outer diameter cylindrical surface 25d Second truncated cone outer surface 25e First large outer diameter cylindrical surface 25f Second large outer diameter cylindrical surface 25g Coil spring fitting cylinder surface 25j flange 25ia small inner diameter cylindrical surface 25ia' small inner diameter cylindrical surface 25ib First truncated cone inner surface 25ic large inner diameter cylindrical surface 25s slit 26 Coil spring 3 Front axle 32 Main Unit 33 Gripping part 4 Intermediate shaft 41 First slot 42 Stepped section 43 Cam section 43a Cam teeth 43b Cam groove 44 External process 5 rear axle 51 Second slot 52 Mounting hole 53 Friction part 54 Introvert process 6 Refills (Cursive) 61 Pen Tip 62 Ink reservoir 63 tail plug 63a Air vent 63b Projection piece 63c Gap 63d Small diameter section 63e Large diameter section 63f Tsubabe 63g engaging surface 63p External process 63t Auxiliary taper part 7. Rotating parts 71 protrusion 72 Protrusion 72a Engagement surface 73 Contact part 74 Annular auxiliary protrusion 74t Auxiliary contact surface 78 External process 8 Knock member 81 Base 82 Shaft 82a cam teeth 83 clips 88 Introvert process 110 Retractable writing instrument 111 Shaft cylinder 111a Posterior part 111b Inner cylinder part 111c front part 111d Cap part 111t Guideway 112 Second coil spring 113 Chip Holder 113a Proximal end 113b 1st Color Section 113c 2nd Color Section 113d Tip 113f Spring fixing auxiliary part 114 chips 115 Annular member 115a Large outer diameter cylindrical part 115b Small outer diameter cylindrical part 115s slit 115t Contact surface 116 Coil spring 120 Retractable writing instrument 123 Chip Holder 123a Proximal end 123b 1st Color Section 123c 2nd Color Section 123d Tip 124 chips 125 Annular Member 125s slit 125t contact surface 126 Resin spring part 126e Resin spring part 130 Retractable writing instrument 132 Colored parts 133 Chip Holder 133a Proximal end 133b 1st Color Section 133c 2nd Color Section 133d Tip 133m intermediate collar section 134 chips 140 Retractable writing instrument 142 Colored parts 143 Chip Holder 143a Proximal end 143b 1st Color Section 143c 2nd Color Section 143d Tip 143m intermediate collar section 144 chips

Claims

1. a barrel having an opening at its front end; a tip holder accommodated inside the barrel and movable in the axial direction of the barrel; a tip fixed to the front end of the tip holder and capable of appearing and disappearing through the opening of the barrel as the tip holder moves; an annular member that is loosely fitted to the inner periphery of the opening of the barrel and is movable in the axial direction of the barrel relative to the barrel; an elastic member that can connect the chip holder and the annular member so that they can move relative to each other; Equipped with a contact surface is formed on at least a portion of the outer periphery of the annular member, the contact surface contacting a portion of the inner surface of the barrel as the tip holder moves toward the front end side; a notch is formed in a portion of the annular member, and an inner diameter of the annular member is reduced when a load is applied to the abutment surface; a guide surface is formed on a part of the inner surface of the barrel, with which the abutment surface abuts as the tip holder moves toward the front end side; The contact surface receives the load from the guide surface as the tip holder moves toward the front end. A retractable writing instrument characterized by:

2. A stopper element provided on the barrel and / or the annular member, which defines a rearward movement limit of the annular member.

2. The retractable writing instrument according to claim 1, further comprising:

3. a plurality of the notches are arranged at equal intervals in the circumferential direction of the annular member, Each of the plurality of notches is a slit extending in the axial direction of the annular member.

3. The retractable writing instrument according to claim 1 or 2.

4. The abutment surface is tapered toward the front end, The guide surface also tapers toward the front end.

4. The retractable writing instrument according to claim 1, wherein the retractable writing instrument is a retractable writing instrument.

5. The abutment surface has a frustoconical surface.

5. The retractable writing instrument according to claim 4.

6. The elastic member is a coil spring.

6. The retractable writing instrument according to claim 1.

7. The annular member and the elastic member are fixed to each other, the resilient member is connectable to an annular collar of the chip holder; The elastic member is separable from the annular collar of the chip holder.

7. The retractable writing instrument according to claim 1.

8. The contact surface and the guide surface are always in contact with each other.

8. The retractable writing instrument according to claim 1.

9. The annular member protrudes forward from the opening of the barrel.

9. The retractable writing instrument according to claim 1.

10. A soft member is provided at the operating portion for operating the tip to extend or retract, or at the rear of the barrel.

10. The retractable writing instrument according to claim 1.

11. a knock member provided slidably in the front-rear direction relative to the barrel; Further provided with The tip is moved back and forth so as to alternately protrude and retract from the opening of the barrel each time the knock member is moved forward, 11. The retractable writing implement according to claim 1, wherein the annular member is adapted to rotate relative to the barrel each time the knock member is moved forward.

Images