Disappearance-style notebook

Abstract

To provide a retractable writing tool which has no risk of hindering of sooth rotation of a refill.SOLUTION: The present invention is a retractable writing tool comprising a barrel having an opening at a front end, a tip holder housed 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 being retracted from the opening of the barrel along with the movement of the tip holder, an annular member loosely fitted to the inner periphery of the opening of the barrel, and an elastic member fixed to the annular member and capable of connecting the tip holder and the annular member so as to be movable relative to each other, in which a sliding surface on which the annular member slides is formed on a part of an inner surface of the barrel.SELECTED DRAWING: Figure 2

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] The applicant of this application, in Patent Application No. 2020-211780, 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 is proposed.

[0003] With this retractable writing instrument, 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 hold the tip or tip holder without any rattle (play).

[0004] More specifically, Fig. 1 is a schematic vertical cross-sectional view of a retractable writing instrument 10 according to one embodiment of the retractable writing instrument, 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.

[0005] 3(a) is an oblique view of the annular member 15 of the retractable writing instrument 10, 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).

[0006] Furthermore, Figure 4 is a schematic diagram showing the state in which tip 14 comes into contact with annular member 15 during the process of protruding tip 14 in retractable writing instrument 10, Figure 5 is a schematic diagram showing the state in which tip 14 is most protruding during the process of protruding tip 14 in retractable writing instrument 10, 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 retractable writing instrument 10.

[0007] The retractable writing instrument 10 shown in Figures 1 to 6 includes a cylindrical barrel 11 having an opening at its front end. As shown in Figure 1, the barrel 11 has a rear portion 11r and a front portion 11m. The rear portion 11r and the front portion 11m are removably fixed together by a screw connection (threaded engagement). However, the rear portion 11r and the front portion 11m may be fixed together by a fitting connection, or may be formed integrally.

[0008] 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.

[0009] 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. The base end portion 13a and the first collar portion 13b are both cylindrical, while the second collar portion 13c is frustoconical, with the cross-sectional diameters of these portions being in the order base end portion 13a > first collar portion 13b > second collar portion 13c.

[0010] As shown in Fig. 2, 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 enlarged outer diameter and an enlarged inner diameter, and covers the periphery of the tip 14 (φ2.5) without contacting it.

[0011] 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.

[0012] The annular member 15 is made of resin (for example, polyacetal, polypropylene, or polyethylene) or metal (for example, brass).

[0013] 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).

[0014] 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, the front end of the coil spring 16 is fixed (fitted) onto the four-sided sweep portion 15ie.

[0015] Three slits 15s are formed as cutouts in the annular member 15. 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 from the front end to approximately the center of the second truncated cone outer surface 15d in the axial direction of the annular member 15 (maximum axial length: 5.5 mm).

[0016] 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.

[0017] 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.

[0018] 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.

[0019] Coil spring 16 also has the function of automatically retracting tip holder 13 when tip 14 is retracted (for example, by sliding an operating part provided on the side of the writing instrument to release the locking mechanism that keeps tip 14 protruding). In other words, 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 (Figure 2) is 68 gf, the load at full stroke (Figure 5) is 288 gf, and the operating load when writing (Figure 6) is 227 gf. The spring constant is 0.23 N / mm.)

[0020] The retractable writing instrument 10 configured as above operates as follows.

[0021] 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).

[0022] 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.

[0023] 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.

[0024] The inner diameter when reduced corresponds to the outer diameter of the tip 14. In other words, the minimum inner diameter when reduced (for example, approximately 2.35 mm to 2.45 mm) allows the tip 14 (for example, φ2.5 mm) to slide smoothly in the axial direction, while providing effective anti-vibration for the tip 14 in the radial direction.

[0025] Furthermore, the second truncated cone outer surface 15d abuts against the second truncated cone inner surface 11id, thereby defining a limit to the forward movement of the annular member 15. That is, 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 a stopper element that defines the limit to the forward movement of the annular member 15. However, such a stopper element can be omitted.

[0026] 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.

[0027] 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).

[0028] 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 0024), 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] As described above, with the retractable writing instrument 10, 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, a stopper element functions to determine the limit of forward movement 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 0024), 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.

[0033] Furthermore, according to the retractable writing instrument 10, 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.

[0034] 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.

[0035] 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.

[0036] In addition, 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).

[0037] Furthermore, according to the retractable writing instrument 10, 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).

[0038] Furthermore, according to the retractable writing instrument 10, 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.

[0039] Furthermore, according to the retractable writing instrument 10, 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. This prevents the contact surface of the annular member 15 and the guide surface of the barrel 11 from repeatedly coming into contact with and separating from each other every time the tip 14 is extended or retracted, resulting in stable operation and a smooth feel to the user (no discomfort).

[0040] Furthermore, according to the retractable writing instrument 10, 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.

[0041] Furthermore, according to the retractable writing instrument 10, 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, so that the annular member 15 can be effectively prevented from undesirably falling off, etc.

[0042] (Additional information about the rotation of Refill 6) In the retractable writing instrument 10, 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.

[0043] (Additional information regarding the rotation of the annular member 15) When the refill 6 is rotated relative to the barrel 11 by the pressing operation of the knock member 8, the annular member 15 connected to the refill 6 via the coil spring 16 is also rotated relative to the barrel 11.

[0044] At this time, the front end of the coil spring 16 is fixed to the annular member 15. As a result, the front end of the coil spring 16 does not slide on the inner surface of the annular member 15, and there is no risk of the front end damaging the annular member 15. In addition, the annular member 15 connected to the refill 6 via the coil spring 16 is also rotated relative to the barrel 11, allowing the refill 6 and the coil spring 16 to rotate together. As a result, the rear end of the coil spring 16 does not slide on the tip holder 13, and there is no risk of the rear end damaging the tip holder 13. In addition, as the refill 6, the annular member 15, and the coil spring 16 rotate together, there is no risk of the smooth rotation of the refill 6 (and therefore the pressing operation of the knock member 8) being hindered.

[0045] Patent Documents 1 to 4, which were introduced as prior art documents in Patent Application No. 2020-211780, are listed below. [Prior art documents] [Patent documents]

[0046] [Patent Document 1] Jippan Hei 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]

[0047] The main function of annular member 15 of retractable writing instrument 10 is to hold tip 14 without rattle (play) due to the presence of slits 15s. However, the present inventors focused on the function of annular member 15 as a spring support that supports coil spring 16 (elastic member) of annular member 15, rather than the above function, and discovered that a retractable writing instrument equipped with an annular member that does not have the former function but only the latter function also exhibits a significantly useful effect.

[0048] The present invention has been made in light of the above findings, and its object is to provide a retractable writing instrument in which the smooth rotation of the refill is not hindered. [Means for solving the problem]

[0049] The present invention is a retractable writing instrument comprising a barrel having an opening at its front end, a tip holder housed 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 protruding and retracting from the opening in the barrel as the tip holder moves, an annular member loosely fitted into the inner circumference of the opening in the barrel, and an elastic member fixed to the annular member and capable of connecting the tip holder and the annular member so that they can move relative to each other, and wherein a sliding surface along which the annular member slides is formed on a portion of the inner surface of the barrel.

[0050] According to the present invention, a sliding surface on which the annular member slides is formed on a portion of the inner surface of the barrel, so that when the tip holder (refill) is rotated relative to the barrel, for example by pressing the knock member, the tip holder (refill), elastic member and annular member rotate together, and there is no risk of the smooth rotation of the tip holder (refill) (and thus the pressing operation of the knock member) being hindered.

[0051] 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.

[0052] Preferably, the sliding surface has a front end sliding surface on which the front end of the annular member (front end surface, front protrusion, etc.) slides. With this, by adjusting the elastic force of the elastic member, it is possible to relatively easily adjust the sliding state between the front end of the annular member and the front end sliding surface of the barrel.

[0053] In this case, it is more preferable that the front end sliding surface is a surface perpendicular to the axial direction of the barrel, thereby enabling smoother adjustment of the sliding state between the front end of the annular member and the front end sliding surface of the barrel.

[0054] Preferably, the elastic member is a coil spring.

[0055] Preferably, the device further includes a knock member slidably mounted in the front-rear direction relative to the barrel, and the tip is moved back and forth so as to alternately protrude and retract into 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 is rotated in accordance with the forward movement (operation) of the knock member.

[0056] The present invention also covers only the barrel of the retractable writing instrument. That is, the present invention relates to a barrel for a retractable writing instrument that can accommodate a tip holder having a tip fixed to its front end so as to be movable in the axial direction, has an opening at its front end, and is capable of protruding and retracting the tip from the opening as the tip holder moves, and includes: an annular member that is loosely fitted around the inner periphery of the opening of the barrel; and an elastic member that is fixed to the annular member and that can connect the tip holder and the annular member so as to be movable relative to each other, and a sliding surface along which the annular member slides is formed on a portion of the inner surface of the barrel. [Effects of the Invention]

[0057] According to the present invention, a sliding surface on which the annular member slides is formed on a portion of the inner surface of the barrel, so that when the tip holder (refill) is rotated relative to the barrel, for example by pressing the knock member, the tip holder (refill), elastic member and annular member rotate together, and there is no risk of the smooth rotation of the tip holder (refill) (and thus the pressing operation of the knock member) being hindered.

[0058] 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] This is a schematic vertical cross-sectional view of the retractable writing instrument disclosed in Patent Application No. 2020-211780, showing the state in which the 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. 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 8] FIG. 8 is an enlarged vertical cross-sectional view of the tip portion of the retractable writing implement of FIG. [Figure 9] Fig. 9(a) is a perspective view of the annular member of the retractable writing instrument of Fig. 7. Fig. 9(b) is a front view of the annular member of Fig. 9(a). Fig. 9(c) is a side view of the annular member of Fig. 9(a). Fig. 9(d) is a rear view of the annular member of Fig. 9(a). Fig. 9(e) is a cross-sectional view taken along line AA of Fig. 9(d). [Figure 10] FIG. 10 is a schematic diagram showing the retractable writing instrument of FIG. 7 with the refill removed. [Figure 11] FIG. [Figure 12] FIG. 2 is a perspective view of the rear end portion of the refill. [Figure 13] FIG. 2 is a plan view of the rear end portion of the refill. [Figure 14] FIG. 1 is a longitudinal cross-sectional view of a front barrel of an exemplary barrel. [Figure 15] FIG. 2 is a longitudinal cross-sectional view of an intermediate shaft of an exemplary barrel. [Figure 16] FIG. 1 is a longitudinal cross-sectional view of an exemplary rear barrel. [Figure 17] FIG. 2 is a vertical cross-sectional view of a knock member. [Figure 18] FIG. [Figure 19] FIG. [Figure 20] FIG. [Figure 21] 21 is a cross-sectional view taken along line CC in FIG. 20. [Figure 22] 1 is a schematic diagram illustrating the principle of a rotation cam mechanism. [Figure 23] 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 24] 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 25]FIG. 3 is a view corresponding to FIG. 2, showing an embodiment in which the winding direction of the coil spring is reversed. [Figure 26] Figure 26(a) is a perspective view of an annular member of a retractable writing instrument according to a second embodiment of the present invention. Figure 26(b) is a front view of the annular member of Figure 26(a). Figure 26(c) is a side view of the annular member of Figure 26(a). Figure 26(d) is a rear view of the annular member of Figure 26(a). Figure 26(e) is a cross-sectional view taken along line AA of Figure 26(d). [Figure 27] Figure 27(a) is a perspective view of an annular member of a retractable writing instrument according to a third embodiment of the present invention. Figure 27(b) is a front view of the annular member of Figure 27(a). Figure 27(c) is a side view of the annular member of Figure 27(a). Figure 27(d) is a rear view of the annular member of Figure 27(a). Figure 27(e) is a cross-sectional view taken along line AA of Figure 27(d). 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. 7 is a schematic vertical cross-sectional view of the retractable writing instrument 110 according to the first embodiment of the present invention, showing a state in which the tip 114 (writing element) is not protruding. Fig. 8 is an enlarged vertical cross-sectional view of the tip portion of the retractable writing instrument 110 according to this embodiment.

[0062] Also, Figure 9(a) is an oblique view of the annular member 115 of the retractable writing instrument 110 of this embodiment, Figure 9(b) is a front view of the annular member 115 of Figure 9(a), Figure 9(c) is a side view of the annular member 115 of Figure 9(a), Figure 9(d) is a rear view of the annular member 115 of Figure 9(a), and Figure 9(e) is a cross-sectional view along line AA of Figure 9(d).

[0063] FIG. 10 is a schematic diagram showing the retractable writing instrument 110 of this embodiment with the refill 6 removed.

[0064] The retractable writing instrument 110 of the first embodiment shown in FIGS. 7 to 10 includes a cylindrical barrel 111 having an opening at its front end. As shown in FIG. 7, the barrel 111 in this embodiment has a rear portion 111r and a front portion 111m. The rear portion 111r and the front portion 111m are removably fixed together by a screw connection (threaded engagement). However, the rear portion 111r and the front portion 111m may also be fixed together by a fitting connection, or may be formed integrally. A portion of the front portion 111m is further surrounded by a grip portion 111n made of an elastic material. The grip portion 111n is formed on the outer surface of the front portion 111m by, for example, two-color molding, or is formed separately and then attached.

[0065] 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.

[0066] 8, the tip holder 113 has, in this order from the base end to the tip end, a base end 113a, a first collar portion 113b, and a second collar portion 113c. In this embodiment, the base end 113a and the first collar portion 113b are both cylindrical, and the second collar portion 113c is a frustoconical portion, with the cross-sectional diameters of the base end 113a > first collar portion 113b > second collar portion 113c.

[0067] 8, an annular member 115 is loosely fitted to the inner periphery of the barrel 111 and covers the periphery of the tip 114 (e.g., φ2.5) without contacting it. A front end surface 115f of the annular member 115 is a surface perpendicular to the axial direction of the barrel 111.

[0068] Correspondingly, a front end surface sliding surface 111f, on which a front end surface 115f of the annular member 115 slides, is formed on part of the inner surface of the barrel 111. The front end surface sliding surface 111f is also a surface perpendicular to the axial direction of the barrel 111.

[0069] The annular member 115 has a front end surface 115f on the outer circumferential side thereof provided with a rounded portion 115a (which may be a chamfered portion) to avoid interference with the corners of the periphery of the front end surface sliding surface 111f.

[0070] The annular member 115 is fixed to the front end of a coil spring 116 (an example of an elastic member). The coil spring 116 surrounds the second collar portion 113c of the tip holder 113 and the tip 114 in a loose fit (with a gap), and the rear end of the coil spring 116 is constantly pressed by (not fixed to) the base end portion 113a of the tip holder 113. As a result, the coil spring 116 connects the tip holder 113 and the annular member 115 so that they can move relative to each other.

[0071] The annular member 115 is made of resin (for example, polyacetal, polypropylene, or polyethylene) or metal (for example, brass).

[0072] As shown in Figures 9(a) to 9(e), the outer peripheral surface of the annular member 115 is a cylindrical surface 115b (φ6.6 mm, axial length 4.6 mm) with a rounded portion 115a formed at the front end.

[0073] On the other hand, as shown in Figures 9(a) to 9(e), the inner surface of the annular member 115 is provided, in this order from the front side, with a small inner diameter cylindrical surface 115ia (φ4.5 mm, axial length 1.1 mm), a large inner diameter cylindrical surface 115ib (φ5.4 mm, axial length 3.1 mm), and a truncated conical inner surface 115ic (axial length 0.4 mm: provided to facilitate insertion of the coil spring 116).

[0074] Also, as shown in Figures 9(d) and 9(e), in this embodiment, inward protrusions 115id for fitting and fixing the front end of the coil spring 116 are provided at four circumferentially even positions on the large inner diameter cylindrical surface 115ib on the small inner diameter cylindrical surface 115ia side.

[0075] 8, a cylindrical portion 111c (φ6.7 mm, axial length 4.7 mm) is formed on the inner surface of the barrel 111, facing the cylindrical surface 115b of the annular member 115, and a front end sliding surface 111f is formed continuously at the front end of the cylindrical portion 111c (the boundary between the two forms a right-angled corner). Also, an inward annular protrusion 111d (minimum aperture diameter φ6.5 mm, axial length 1.4 mm) is provided on the rear side of the cylindrical portion 111c to prevent the annular member 115 from slipping out rearward.

[0076] Furthermore, the coil spring 116 of this embodiment also has the function of automatically retracting the tip holder 113 when the tip 114 is retracted (for example, by sliding an operating portion provided on the side of the writing implement to release the locking mechanism that keeps the tip 114 protruding). In other words, the coil spring 116 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. 8) is 68 gf, the load at full stroke is 288 gf, and the operating load when writing is 227 gf. The spring constant is 0.23 N / mm.)

[0077] The retractable writing instrument 110 configured as above operates as follows.

[0078] When not in use, the tip 114 (writing element) of the retractable writing instrument 110 is in a retracted state as shown in Figures 7 and 8. At this time, the axial length of the coil spring 116 is 16.3 mm.

[0079] When the tip 114 is projected (the knock member 8 is moved forward), the second collar portion 113c of the tip holder 113 is moved forward.

[0080] In the retractable writing instrument 110, each time the knock member 8 is moved forward, it moves back and forth to protrude or retract the pen tip 61 from the opening of the barrel 111, and the refill 6 (and therefore the pen tip 61) is rotated. Writing instruments in which the pen tip 61 rotates in this way are popular on the market because they can even out wear on the pen tip 61.

[0081] When the refill 6 is rotated relative to the barrel 111 by the pressing operation of the knock member 8, the annular member 115 connected to the refill 6 via the coil spring 116 is also rotated relative to the barrel 111.

[0082] At this time, the front end of the coil spring 116 is fixed to the annular member 115. As a result, the front end of the coil spring 116 does not slide on the inner surface of the annular member 115, and there is no risk of the front end damaging the annular member 115. Furthermore, the annular member 115, which is connected to the refill 6 via the coil spring 116, is also rotated relative to the barrel 111, and the refill 6 and the coil spring 116 can rotate together. As a result, the rear end of the coil spring 116 does not slide on the tip holder 113, and there is no risk of the rear end damaging the tip holder 113. Furthermore, as the refill 6, the annular member 115, and the coil spring 116 rotate together, there is no risk of the smooth rotation of the refill 6 (and thus the pressing operation of the knock member 8) being hindered.

[0083] When the tip 114 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 the tip holder 113 is usually locked, and the tip 114 remains extended until the tip 114 is subsequently retracted. At this time, the axial length of the coil spring 116 is 9.9 mm (compressed 6.4 mm).

[0084] Thereafter, when the tip 114 is retracted (which also involves moving the knock member 8 forward), for example, a locking mechanism (not shown) is released, and the tip 114 returns to the retracted state shown in FIG.

[0085] At this time, the refill 6 is rotated relative to the barrel 111 by the pressing operation of the knock member 8, and the annular member 115 connected to the refill 6 via the coil spring 116 is also rotated relative to the barrel 111.

[0086] Even at this time, the front end of the coil spring 116 is fixed to the annular member 115. As a result, the front end of the coil spring 116 does not slide on the inner surface of the annular member 115, and there is no risk of the front end damaging the annular member 115. Furthermore, the annular member 115, which is connected to the refill 6 via the coil spring 116, is also rotated relative to the barrel 111, and the refill 6 and the coil spring 116 can rotate together. As a result, the rear end of the coil spring 116 does not slide on the tip holder 113, and there is no risk of the rear end damaging the tip holder 113. Furthermore, as the refill 6, the annular member 115, and the coil spring 116 rotate together, there is no risk of the smooth rotation of the refill 6 (and thus the pressing operation of the knock member 8) being hindered.

[0087] During the above-described process of the tip extension and retraction operation, the front end surface 115f of the annular member 115 and the front end sliding surface 111f of the barrel 111 are always in contact with each other.

[0088] As described above, according to the retractable writing instrument 110 of this embodiment, a front end surface sliding surface 111f is formed on a part of the inner surface of the barrel 111 as a sliding surface against which the annular member 115 slides. Therefore, when the tip holder 113 (refill 6) is rotated relative to the barrel, for example, by pressing the knock member 8, the tip holder 113 (refill 6), the coil spring 116 and the annular member 115 rotate together, and there is no risk that the smooth rotation of the tip holder 113 (refill 6) (and thus the pressing operation of the knock member) will be hindered.

[0089] Furthermore, according to the retractable writing instrument 110 of this embodiment, the coil spring 116 functions as a "knock spring," so there is no need to use a separate coil spring for the knock spring. This reduces the number of parts, simplifies assembly work, and significantly reduces the risk of malfunction.

[0090] Furthermore, according to the retractable writing instrument 110 of this embodiment, the front end surface 115f of the annular member 115 slides on the front end surface sliding surface 111f. This makes it possible to adjust the sliding state between the front end surface 115f of the annular member 115 and the front end surface sliding surface 111f of the barrel 111 relatively easily by adjusting the elastic force of the coil spring 116.

[0091] Furthermore, according to the retractable writing instrument 110 of this embodiment, the front end surface sliding surface 111f is a surface perpendicular to the axial direction of the barrel 111. This allows for smoother adjustment of the sliding state between the front end surface 115f of the annular member 115 and the front end surface sliding surface 111f of the barrel 111.

[0092] Furthermore, according to the retractable writing instrument 110 of this embodiment, the front end surface 115f of the annular member 115 and the front end surface sliding surface 111f of the barrel 111 are always in contact with each other. As a result, the front end surface 115f of the annular member 115 and the front end surface sliding surface 111f of the barrel 111 do not repeatedly come into contact with and separate from each other every time the tip 114 is extended or retracted, so operation is stable and the user feels smooth in operation (no discomfort).

[0093] (Additional information about refills) The retractable writing instrument 110 of this embodiment is a writing instrument that includes a barrel 111, a refill (writing element) contained within the barrel 111, and a retractable mechanism that allows the tip 114 of the refill to be freely retracted and retracted from the opening of the barrel 111.

[0094] An example of a refill will be further explained with reference to Figures 11 to 13. Referring to Figure 11, 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.

[0095] 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.

[0096] (Additional information about the rear end of the barrel 111) The barrel 111 of this embodiment comprises, for example, a tapered cylindrical front barrel 3 (see FIG. 14), a cylindrical intermediate barrel 4 (see FIG. 15) connected to the rear end of the front barrel 3, and a cylindrical rear barrel 5 (see FIG. 16) connected to the rear end of the intermediate barrel 4.

[0097] 16 , 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.

[0098] 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.

[0099] 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.

[0100] (Additional information about knock member 8) 17, 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.

[0101] 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.

[0102] As shown in FIG. 17, 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. 18 to 21).

[0103] 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).

[0104] The rear axle 5, which has a friction portion 53 fixed to its rear end, is connected to the rear end of the intermediate shaft 4, so that the friction portion 53 is always fixed to the rear end of the barrel 11. Furthermore, because the front axle 3 and the intermediate shaft 4 are detachably connected by screwing, the refill 6 can be replaced at any time. Furthermore, in this embodiment, an annular member 115 is loosely fitted into the inner periphery of the barrel 111, and the front end of a coil spring 116 is fixed to the annular member 115. As a result, the annular member 115 and the coil spring 116 do not separate from the barrel 111 when the refill 6 is replaced, making it easy to replace the refill 6.

[0105] (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 111 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 111 and can engage or disengage with the retractable rotating member 7 depending on the position of the knock member 8, and a knock spring (e.g., a compression coil spring) that is provided within the barrel 111 and urges the refill 6 backward.

[0106] 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.

[0107] (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.

[0108] 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.

[0109] (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 pen tip 61 from the opening of the barrel 111, and the refill 6 (and therefore the pen tip 61) is rotated. Writing instruments in which the pen tip 61 rotates in this way are popular on the market because they can even out wear on the pen tip 61.

[0110] Fig. 22 is a schematic diagram illustrating the principle of the rotary cam mechanism. Referring to Fig. 23, when the knock member 8 is pressed (slid) forward from the pen tip retracted state (see Fig. 22(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.

[0111] 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.

[0112] 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 22(b)).

[0113] Subsequently, when the knock member 8 is returned to its original position by the rearward bias 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. 22(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.

[0114] Next, when the knock member 8 is pressed (slid) forward from the pen tip protruding state (see Figure 22(c)), the rear end of the protrusion 71 of the retractable rotating member 7 is again engaged by the cam teeth 82a at the front end of the shaft portion 82 of the knock member 8 and is pressed forward.

[0115] 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 rotating member 7 to rotate slightly in the circumferential direction (see FIG. 22(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 is maintained in the retracted state (see FIG. 22(a)).

[0116] 23 and 24 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.

[0117] 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.

[0118] 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.

[0119] (Rotation direction of refill 6 and winding direction of coil spring 116) In the embodiment described above, the rotation direction of the refill 6 is clockwise when viewed from the rear end side, and the winding direction of the coil spring 116 is counterclockwise (a so-called left-handed spring) (extending counterclockwise from the start of winding: see Figure 8).

[0120] However, if the rotation direction of the refill 6 and the winding direction of the coil spring 116 are aligned, the tip holder 113 (the coil spring abutment portion thereof) will be oriented so as to push the rear end of the coil spring 116 when the refill 6 rotates, which makes the connection between the tip holder 113 and the coil spring 116 firm (for example, so that the two are hooked together), making it easier for the coil spring 116 to transmit the rotational force of the refill 6 to the annular member 115, which is preferable.

[0121] FIG. 25 is a view corresponding to FIG. 8, showing an embodiment in which the winding direction of the coil spring 116 is reversed.

[0122] Here, it is further preferable that the coil spring abutment portion of the chip holder 113 be provided with an uneven shape or the like to make the connection with the rear end of the coil spring 116 more firm.

[0123] Second Embodiment Also, Figure 26(a) is an oblique view of the annular member of the retractable writing instrument of the second embodiment of the present invention, Figure 26(b) is a front view of the annular member of Figure 26(a), Figure 26(c) is a side view of the annular member of Figure 26(a), Figure 26(d) is a rear view of the annular member of Figure 26(a), and Figure 26(e) is a cross-sectional view along line AA of Figure 26(d).

[0124] As shown in Figures 26(a) to 26(e), the front end surface 115f of the annular member 115' in this embodiment is provided with three (or four or more) forward protrusions 115p' that protrude further forward. The three (or four or more) forward protrusions 115p' are arranged approximately evenly in the circumferential direction, and each forward protrusion 115p' is formed in a hemispherical shape with a radius of 0.2 mm, for example. The axial length of the cylindrical surface 115b and the axial length of the small inner diameter cylindrical surface 115ia are shorter than those in the above-mentioned embodiment by the amount of the protrusion length of the forward protrusions 115p'.

[0125] According to this embodiment, the presence of the three forward protrusions 115p' effectively prevents the front end surface 115f of the annular member 115' and the front end surface sliding surface 111f from sticking together (the static friction force becoming excessive), and allows the two to always start sliding smoothly.

[0126] 26(a) to 26(e), even if a rounded portion (the element designated by reference numeral 115a in FIGS. 9(a) to 9(e)) is not provided at the front end of the outer circumferential surface of the annular member 115, the portion does not interfere with the corners of the periphery of the front end surface sliding surface 111f. In other words, according to this embodiment, the step of providing the rounded portion (115a) can be omitted.

[0127] <Third embodiment> In both of the above two embodiments, inward protrusions 115id for fitting and fixing the front end of the coil spring 116 are provided at four circumferentially even positions on the large inner diameter cylindrical surface 115ib on the small inner diameter cylindrical surface 115ia side.

[0128] The present invention is not limited to this embodiment, and for example, an outward protrusion for fitting and fixing the front end of the coil spring 116 may be provided on the outer circumferential surface of the annular member.

[0129] Figure 27(a) is an oblique view of the annular member of the retractable writing instrument of the third embodiment of the present invention, Figure 27(b) is a front view of the annular member of Figure 27(a), Figure 27(c) is a side view of the annular member of Figure 27(a), Figure 27(d) is a rear view of the annular member of Figure 27(a), and Figure 27(e) is a cross-sectional view along line AA of Figure 27(d).

[0130] As shown in Figures 27(a) to 27(e), the inner peripheral surface of the annular member 115'' is formed as a cylindrical surface 115ia'' (φ3.4 mm, axial length 4.6 mm) over the entire surface.

[0131] As shown in Figures 27(d) and 27(e), the outer peripheral surface of the annular member 115" is provided with, in that order, a large outer diameter cylindrical surface 115b" (φ6.6 mm, axial length 1.1 mm) with an R portion 115a" formed at the front end, a small outer diameter cylindrical surface 115c" (φ4.5 mm, axial length 3.3 mm), and a truncated conical outer surface 115e" (axial length 0.2 mm: provided to facilitate insertion of the coil spring 116).

[0132] In this embodiment, outward protrusions 115d" for fitting and fixing the front end of the coil spring 116 are provided at four circumferentially even positions on the small outer diameter cylindrical surface 115c" on the large outer diameter outer cylindrical surface 115b" side.

[0133] On the other hand, although not shown in the figures, a cylindrical portion (φ6.7 mm, axial length 1.2 mm) is formed on the inner surface of the barrel 111, facing the large outer diameter cylindrical surface 115b" of the annular member 115", and a front end surface sliding surface 111f is formed continuously at the front end of the cylindrical portion (the boundary between the two forms a right-angled corner). In addition, an inward annular convex portion (minimum aperture diameter φ6.5 mm, axial length 1.4 mm) is provided on the rear side of the cylindrical portion to prevent the annular member 115" from slipping out rearward.

[0134] The third embodiment as described above can also provide the same effects as the first and second embodiments. [Explanation of symbols]

[0135] 3 Front axle 4 Intermediate shaft 5 rear axle 6 Refills 7. Rotating parts 8 Knock member 10 Removable writing instrument 11 Shaft tube 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 16 Coil spring 21 Slide hole 41 First slot 43 Cam section 43a Cam teeth 43b Cam groove 44 External process 51 Second slot 52 Mounting hole 53 Friction part 54 Introvert process 61 Pen Tip 62 Ink reservoir 63 tail plug 63a Air vent 63b Projection piece 63c Gap 71 protrusion 72 Protrusion 73 Contact part 81 Base 82 Shaft 82a cam teeth 83 clips 110 Retractable writing instrument 111 Shaft cylinder 111c Cylindrical part 111d Inward circular convex part 111f Front end sliding surface 111m front part 111n Grip 111r rear part 113 Chip Holder 113a Proximal end 113b 1st Color Section 113c 2nd Color Section 114 chips 115 Annular member 115a R section 115b Cylindrical surface 115f Front end surface 115ia small inner diameter cylindrical surface 151ib Large inner diameter cylindrical surface 115ic truncated cone inner surface 115id Inward convex part 116 Coil spring 115' Annular member 115p' Anterior process 115" annular member 115b" Large outer diameter cylindrical surface 115c" small outer diameter cylindrical surface 115d" outward convex part 115e” truncated cone exterior 115ia” cylindrical surface

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 loosely fitted to the inner periphery of the opening of the barrel; an elastic member fixed to the annular member and capable of connecting the chip holder and the annular member so as to be movable relative to each other; Equipped with a sliding surface on which the annular member slides is formed on a part of the inner surface of the barrel, the sliding surface has a front end sliding surface on which a front end of the annular member slides, The front end sliding surface is a surface perpendicular to the axial direction of the barrel. A retractable writing instrument characterized by:

2. The elastic member is a coil spring.

2. The retractable writing instrument according to claim 1.

3. 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, The annular member is adapted to rotate relative to the barrel each time the knock member is moved forward.

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

4. 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 loosely fitted to the inner periphery of the opening of the barrel; an elastic member fixed to the annular member and capable of connecting the chip holder and the annular member so as to be movable relative to each other; Equipped with a sliding surface on which the annular member slides is formed on a part of the inner surface of the barrel, 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, The annular member is adapted to rotate relative to the barrel each time the knock member is moved forward. A retractable writing instrument characterized by:

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