Haunted Notepad

Abstract

To provide a retractable writing instrument capable of solving the problem of a retractable writing instrument disclosed in a patent document 1, specifically, difficulty of assembling of the retractable writing instrument or replacing of a writing instrument body caused by falling-off of a slider or a cam barrel from a rear shaft front end opening which occurs due to removability of the slider from the rear shaft front end opening and removability of the cam barrel from the front of the slider.SOLUTION: This retractable writing instrument is configured such that a slider is disposed so as to be irremovable from a rear shaft front end opening, a writing instrument body and the slider are inserted through a through-hole of a cam barrel, said insertion inserted into the through-hole of the cam barrel being allowed only from behind the slider, and the cam barrel is irremovable from the front of the slider.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a so-called retractable writing instrument in which a writing instrument body having a writing part at its front end is arranged inside a barrel so as to be movable back and forth, and the writing part can be protruded from and retracted into the front end opening of the barrel. Hereinafter, the direction in which the writing part protrudes is referred to as the front, and the direction in which the writing part retracts is referred to as the rear. In addition, the state in which the writing part protrudes from the front end opening of the barrel and is ready for writing is referred to as the protruding state, and the state in which the writing part retracts into the barrel is referred to as the retracted state. [Background technology]

[0002] As a retractable writing instrument, one in which a so-called cam mechanism is adopted as at least a part of the retractable mechanism is known. In the cam mechanism in the retractable writing instrument, a locking protrusion is provided on a slider arranged at the rear of the writing instrument body so that the writing instrument body can be locked at different positions in the front and rear inside the barrel. A cam portion is provided inside the barrel as a locking destination of the locking protrusion. The cam portion displaces in the circumferential direction with the forward and rearward movement of the writing instrument body and the slider, thereby enabling the writing part to be retracted in a single continuous operation by simply moving the writing instrument body and the slider forward and rearward. In such a retractable writing instrument, in order to form a protruding state, the writing instrument body and the slider are advanced until the locking protrusion is located forward of the cam portion. Thereafter, the writing instrument body is retracted by a force such as the biasing force of the elastic member, and the locking protrusion is engaged with the cam portion, so that the retraction of the writing instrument body stops and the protruding state can be formed.

[0003] For example, Patent Document 1 (Japanese Utility Model Publication No. 54-38980) discloses a retractable writing instrument that has a writing instrument body biased rearward by a resilient member inside a barrel, and a cam cylinder that can rotate around the outer periphery of a slider located at the rear of the writing instrument body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Jpn. Jpn. Published No. 54-38980 Summary of the Invention [Problem to be solved by the invention]

[0005] In the retractable writing instrument disclosed in Patent Document 1, the slider can be removed from the front end opening of the rear shaft, and the cam cylinder can be removed from the front of the slider. When assembling the writing instrument body, if the front shaft and the rear shaft are released from the front end opening of the rear shaft, the slider and the cam cylinder may fall off from the front end opening of the rear shaft. This causes a problem that it becomes difficult to assemble the retractable writing instrument itself and to replace the writing instrument body.

[0006] An object of the present invention is to provide a retractable writing instrument that allows easy assembly of the retractable writing instrument itself and easy replacement of the writing instrument body. [Means for solving the problem]

[0007] The gist of the present invention is a retractable writing instrument in which at least a writing instrument body, a slider, and a cam barrel are arranged inside a barrel in which a front barrel and a rear barrel are detachably joined, the writing instrument body is arranged to be movable back and forth by a rearward biasing force from a resilient member and a forward force caused by operation of a knock portion exposed to the outside of the barrel via the slider detachably attached to the rear of the writing instrument body, the slider is arranged so as to be unremovable from at least the front end opening of the rear barrel, the writing instrument body and the slider are arranged to pass through a through hole of the cam barrel, and a locking protrusion provided on the outer wall surface of the writing instrument body and / or the slider can be engaged with and released from a cam portion provided on the cam barrel, thereby allowing the writing portion provided at the front end of the writing instrument body to be retracted from the front end opening of the barrel, the slider can be inserted into the through hole of the cam barrel only from the rear of the slider, and the cam barrel cannot be removed from the front of the slider. Effect of the Invention

[0008] In the retractable writing instrument of the present invention, when the front and rear shafts are released from the connection, the slider cannot be removed from the opening at the front end of the rear shaft, so it will not fall off from the opening at the front end of the rear shaft. Since the cam cylinder cannot be removed from the front of the slider, the user does not need to pay attention to parts other than the writing instrument body falling off, and assembly of the retractable writing instrument itself and replacement of the writing instrument body can be simplified. [Brief description of the drawings]

[0009] [Figure 1] Appearance of ballpoint pen 1 [Diagram 2] A-A' cross section of Figure 1 [Diagram 3] 1A and 1B are perspective views of the cam barrel 5. [Figure 4] Cam mechanism deployment diagram in immersed state [Diagram 5] FIG. 5 is a diagram showing the ballpoint pen refill 3 and the slider 4 advanced from the state shown in FIG. [Figure 6] FIG. 6 is a diagram showing the ballpoint pen refill 3 and the slider 4 advanced from the state shown in FIG. 5. [Figure 7] FIG. 7 is a diagram in which the ballpoint pen refill 3 and the slider 4 are retracted from the state of FIG. 6. [Figure 8] Exploded view of the cam mechanism in the extended state [Figure 9] FIG. 9 is a diagram showing the ballpoint pen refill 3 and the slider 4 advanced from the state shown in FIG. 8. [Figure 10] Enlarged cross-sectional view of the vicinity of the joint between the ballpoint pen refill 3 and the slider 4 [Figure 11] FIG. 3 is a perspective view of the appearance of the slider 4. [Figure 12] A vertical cross-sectional perspective view of the cam barrel 5. [Figure 13] A diagram showing a case where the operating protrusion 4a comes into contact with the cam portion 5a. [Figure 14] FIG. 14 is a diagram showing the cam barrel 5 advanced from the state shown in FIG. 13. [Figure 15] FIG. 15 is a diagram showing the cam barrel 5 advanced from the state shown in FIG. 14 . [Figure 16] FIG. 13 shows a case where the operating protrusion 4a does not abut against the front end surface of the side wall of the cam barrel 5. [Figure 17]External view of the clip 7 from the shaft cylinder 2 side [Figure 18] FIG. 13 is an external view of the shaft tube 2 side of the clip 7 according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention can be embodied as a retractable writing instrument such as a ballpoint pen, mechanical pencil, brush pen, felt-tip pen, or marking pen, in which a writing part such as a ballpoint pen tip can be projected and retracted from an opening at the front end of a barrel. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] Fig. 1 is an external view of a ballpoint pen 1, which is a retractable writing instrument according to one embodiment of the present invention, and Fig. 2 is a cross-sectional view taken along the line A-A' in Fig. 1. The ballpoint pen 1 has a ballpoint pen refill 3 as the writing instrument main body, a slider 4, a cam cylinder 5, and a coil spring 6 as a resilient member arranged inside a hollow cylindrical barrel 2.

[0012] The barrel 2 is configured by detachably connecting a front barrel 2a and a rear barrel 2b. The rear open end of the front barrel 2a is inserted into the front open end of the rear barrel 2b. A screw portion is provided on the outer wall surface of the rear open end of the front barrel 2a and the inner wall surface of the front open end of the rear barrel 2b, respectively, so that the front barrel 2a and the rear barrel 2b can be connected by screwing. By releasing the screwing, the ballpoint pen refill 3 can be easily arranged and replaced.

[0013] The front shaft 2a is a so-called two-color molded product, with the primary side located on the radial inside of the front shaft 2a being made of polypropylene resin, and the secondary side located on the radial outside of the front shaft 2a being made of styrene-based triethyl phosphate resin. The outer wall surface of the front shaft 2a is matte-finished, which functions as a grip that makes it easier for the user to hold it in his / her hand.

[0014] The front barrel 2a can be formed into a desired shape by a known method other than two-color molding as in this embodiment. The grip can also be formed as a separate member and configured to cover the outer wall surface of the front barrel 2a.

[0015] The material of the front axle 2a can be appropriately selected from polypropylene resin, polycarbonate resin, acrylic resin, polyethylene resin, polyamide resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polyethylene naphthalate resin, vinyl chloride resin, ethylene-vinyl alcohol copolymer, polyacrylonitrile resin, fluororesin, polyacetal resin, polyethylene terephthalate resin, polystyrene resin, ABS resin, silicone resin, elastomer, composite materials containing these resins, etc. In addition, the molding method is not limited to two-color molding as in this embodiment, and various known methods can be appropriately selected.

[0016] A window hole 2ba is provided in the rear side wall of rear barrel 2b, which extends in the front-rear direction and penetrates from the inside to the outside of rear barrel 2b. A slider 4 is detachably attached to the rear of ballpoint pen refill 3. Slider 4 is connected to clip 7, which is a knock portion exposed to the outside of barrel 2, via window hole 2ba. When clip 7 is operated from rear to front along window hole 2ba, slider 4 and ballpoint pen refill 3 move forward in tandem inside barrel 2, which is a so-called side slide type.

[0017] The knock portion only needs to be linked to the slider 4 and the ballpoint pen refill 3, and may be of a so-called rear end knock type, exposed from the rear end of the rear barrel 2b and pressed forward to form a protruding state.

[0018] The rear axle 2b is a member made of polycarbonate resin. In consideration of moldability and durability, the material of the rear axle 2b may be appropriately selected from polypropylene resin, acrylic resin, polyethylene resin, polyamide resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polyethylene naphthalate resin, vinyl chloride resin, ethylene-vinyl alcohol copolymer, polyacrylonitrile resin, fluororesin, polyacetal resin, polyethylene terephthalate resin, polystyrene resin, ABS resin, silicone resin, elastomer, or composite materials containing these resins.

[0019] The ballpoint pen refill 3, which is the main body of the writing instrument, is composed of a ballpoint pen tip 3a as a writing part and a pipe 3b that holds ink inside. The ink inside the pipe 3b is discharged through the ballpoint pen tip 3a onto a writing surface, allowing the user to write and draw letters, pictures, and the like.

[0020] The rear end of the ballpoint pen refill 3 is inserted into the bottomed cylindrical portion from the front end opening of the slider 4. The ballpoint pen refill 3 is not fixed inside the cylindrical portion of the slider 4, but is loosely fitted therein to such an extent that it can rotate in the circumferential direction.

[0021] The ballpoint pen refill 3 can be advanced inside the barrel 2 by advancing the clip 7 as described above. The front inner wall surface of the front barrel 2a is provided with a stepped portion 2aa, which is a circular protrusion that is connected in the circumferential direction. When the front end surface of the pipe 3ab comes into contact with the stepped portion 2aa, the ballpoint pen refill 3 stops advancing.

[0022] Two coil spring rear end projections 3ba that come into contact with the rear end of the coil spring 6 are provided at equal intervals in the circumferential direction on the outer wall surface of the pipe 3b. Six coil spring front end ribs 2ab that come into contact with the front end of the coil spring 6 are provided at equal intervals in the circumferential direction on the inner wall surface of the front shaft 2a (two of the six are shown). The coil spring 6 is sandwiched between the coil spring rear end projections 3ba and the coil spring front end ribs 2ab in a contracted state from its natural state, and constantly urges the ballpoint pen refill 3 and the slider 4 backward.

[0023] An actuating protrusion 4a and a locking protrusion 4b are provided on the outer wall surface of the slider 4. When each protrusion comes into contact with a cam portion 5a of a cam cylinder 5 described later, the ballpoint pen tip 3a can be protruded and retracted from the front end opening of the barrel 2. The actuating protrusion 4a and the locking protrusion 4b may be provided on the outer wall of the pipe 3b, or only the locking protrusion 4b located at the front in the front-rear direction may be provided on the pipe 3b.

[0024] 3(a) and (b) are external perspective views of the cam barrel 5. In FIG. 3(b), the outer wall of the cam barrel 5 is made transparent, and a part of the cam portion 5a provided on the inner wall surface is illustrated by a dotted line. The cam barrel 5 is a cylindrical member having a through hole penetrating in the front-rear direction. The slider 4 is inserted into the through hole. The cam portion 5a is provided on the inner wall surface of the cam barrel 5. When the slider 4 moves forward or backward, the actuating projection 4a and the locking projection 4b come into contact with the cam portion 5a, and the cam barrel 5 can rotate around the outer periphery of the slider 4. The cam portion 4 is a member whose forward or backward movement is restricted inside the shaft cylinder 2.

[0025] By providing the cam portion 5a on the inner wall surface of the cam barrel 5 as in this embodiment, the degree of freedom in designing the outer wall surface of the cam barrel 5 is increased. In this embodiment, the outer wall surface of the cam barrel 5 can be made longer in the front-rear direction than the cam portion 5a. In other words, both front-rear end portions of the cam portion 5a are not exposed in the front-rear direction from both opening ends of the through hole, and are contained within the front-rear range of the inner wall surface of the cam barrel 5. There is no need to provide other irregularities on the outer wall surface of the cam barrel 5 to make the cam barrel 5 function as a part of the cam mechanism. Therefore, there is no need to provide a part that can become a fulcrum that causes radial rattle on the inner wall surface of the shaft barrel that abuts against the outer wall surface. In addition, it is preferable because the operating sound of the cam mechanism that constitutes the retraction mechanism can be quieted.

[0026] The slider 4 and the cam cylinder 5 are members made of polyacetal resin. In addition, the materials for the slider 4 and the cam cylinder 5 can be appropriately selected from polypropylene resin, polycarbonate resin, acrylic resin, polyethylene resin, polyamide resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polyethylene naphthalate resin, vinyl chloride resin, ethylene-vinyl alcohol copolymer, polyacrylonitrile resin, fluororesin, polyethylene terephthalate resin, polystyrene resin, ABS resin, silicone resin, elastomer, and composite materials containing these resins, taking into consideration moldability and durability.

[0027] Hereinafter, the cam mechanism constituting the projection mechanism in this embodiment will be described with reference to FIG. 4 to FIG. 9. In FIG. 4 to FIG. 9, the slider 4 and the cam cylinder 5 are shown expanded in the circumferential direction so that the contact relationship between the slider 4 and the cam cylinder 5 can be visually confirmed. In addition, in order to easily understand the contact relationship between the slider 4 and the cam cylinder 5, the two members that are originally facing each other in the radial direction are shown on the same plane. Specifically, the operating projection 4a and the locking projection 4b are shown from the perspective of protruding from the back side of the drawing to the front side. Therefore, the cam portion 5a is shown from the perspective of the cam portion 5a provided on the inner wall surface of the cam cylinder 5 from the outside of the cam cylinder 5, in other words, from the base side of the cam portion 5a (the hatching of the cam portion 5a is omitted to improve visibility). Hereinafter, the direction toward the right side of the drawing, which is the rotation direction of the cam cylinder 5, is referred to as the forward rotation direction, and the direction opposite to the forward rotation direction and toward the left side of the drawing is referred to as the rear rotation direction.

[0028] 4 is an exploded view of the cam mechanism in the retracted state. In this state, the ballpoint pen refill 3 and the slider 4 are at their most retracted positions inside the barrel 2. The locking projections 4b and the cam portions 5a are provided at four positions each at equal intervals in the circumferential direction on the outer wall surface of the slider 4 and the inner wall surface of the cam barrel 5, respectively. In the retracted state, the locking projections 4b are alternately positioned between the cam portions 5a. The operating projections 4a are provided at two positions at equal intervals in the circumferential direction on the outer wall surface of the slider 4.

[0029] Fig. 5 is a diagram showing the ballpoint pen refill 3 and the slider 4 advanced from the state shown in Fig. 4. An operating surface 4aa is provided on the front end surface of the side wall of the operating projection 4a. A front operating surface 5aa that abuts against the operating surface 4aa is provided on the rear end surface of the side wall of the cam portion 5a, which is forward in the rotation direction. The operating surface 4aa and the front operating surface 5aa are flat surfaces facing each other, inclined backward in the front-to-rear direction as they move forward in the rotation direction, and inclined forward in the front-to-rear direction as they move backward in the rotation direction.

[0030] FIG. 6 is a diagram showing the ballpoint pen refill 3 and the slider 4 advanced from the state shown in FIG. 5. This state is the state in which the ballpoint pen refill 3 and the slider 4 are advanced to the most advanced state inside the barrel 2. When the ballpoint pen refill 3 and the slider 4 are advanced further from the state shown in FIG. 4 in which the operating surface 4aa and the front operating surface 5aa abut against each other, the cam barrel 5 receives a circumferential force from the operating surface 4aa via the front operating surface 5aa and rotates forward in the rotation direction. The locking protrusion 4b is separated forward from the cam portion 5a, so it does not interfere with the rotation. When the front end surface of the pipe 3ab abuts against the step portion 2ab and the forward movement of the ballpoint pen refill 3 and the slider 4 stops, the rotation of the cam barrel 5 also stops, resulting in the state shown in FIG. 6.

[0031] Fig. 7 is a view showing the ballpoint pen refill 3 and the slider 4 retracted from the state shown in Fig. 6. A locking surface 4ba is provided on the rear end surface of the side wall of the locking projection 4b. A protruding locking surface 5ac that abuts against the locking surface 4ba is provided on the front end surface of the side wall of the cam portion 5a, which is on the front side in the rotation direction. The locking surface 4ba and the protruding locking surface 5ac are flat surfaces facing each other, inclined forward in the front-rear direction as they move forward in the rotation direction and inclined backward in the front-rear direction as they move backward in the rotation direction.

[0032] FIG. 8 is a diagram in which the ballpoint pen refill 3 and the slider 4 are retracted from the state of FIG. 7, and is a development view of the cam mechanism in the protruding state. When the ballpoint pen refill 3 and the slider 4 are further retracted from the state of FIG. 6 in which the locking surface 4ba and the protruding locking surface 5ac are in contact with each other, the cam cylinder 5 receives a circumferential force from the locking surface 3bba via the protruding locking surface 5ac and rotates forward in the rotation direction. The operating protrusion 4a does not interfere with the rotation because it is separated rearward from the cam portion 5a. There is a wall portion along the front-rear direction behind the protruding locking surface 4ba in the rotation direction, and the rear end face of the side wall of the locking protrusion 4b in the rotation direction abuts against it, so that the retraction of the ballpoint pen refill 3 and the slider 4 and the rotation of the cam cylinder 5 stop, resulting in the state shown in FIG. 8.

[0033] FIG. 9 is a diagram showing the ballpoint pen refill 3 and the slider 4 advanced from the state shown in FIG. 8. A rear operating surface 5ab that abuts against the operating surface 4aa is provided on the rear end surface of the side wall of the cam portion 5a, which is located rearward in the rotation direction. The operating surface 4aa and the rear operating surface 5ab are flat surfaces that face each other and are inclined rearward in the front-rear direction as they move forward in the rotation direction, and forward in the front-rear direction as they move rearward in the rotation direction. When the ballpoint pen refill 3 and the slider 4 are advanced from the state shown in FIG. 8, the operating surface 4aa and the rear operating surface 5ab abut against each other. When the ballpoint pen refill 3 and the slider 4 are further advanced, the cam barrel 5 receives a circumferential force from the operating surface 4aa via the rear operating surface 5ab and rotates forward in the rotation direction. The locking protrusion 4b is separated forward from the cam portion 5a, so it does not interfere with the rotation. When the front end face of the pipe 3ab abuts against the step portion 2ab and the forward movement of the ball-point pen refill 3 and the slider 4 stops, the rotation of the cam barrel 5 also stops.

[0034] When the ballpoint pen refill 3 and the slider 4 are retracted from the state shown in FIG. 9, they return to the recessed state shown in FIG. 4. The recessed guide surface 5ad that abuts against the locking surface 4ba is provided on the front end surface of the side wall of the cam portion 5a, which is located rearward in the rotation direction. The recessed guide surface 5ad is a flat surface that faces the locking surface 4ba, inclined forward in the front-rear direction as it moves forward in the rotation direction and backward in the front-rear direction as it moves backward in the rotation direction. When the ballpoint pen refill 3 and the slider 4 are retracted from the state shown in FIG. 8, the locking surface 4ba and the recessed guide surface 5ad abut against each other. When the ballpoint pen refill 3 and the slider 4 are further retracted, the cam cylinder 5 receives a circumferential force from the locking surface 4ba via the recessed guide surface 5ad and rotates forward in the rotation direction. When the cam cylinder 5 rotates until the recessed guide surface 5ad and the locking surface 4ba no longer abut, the locking protrusions 4b are positioned alternately between the cam portions 5a, resulting in a recessed state. The above is the cam mechanism in this embodiment, which moves from the retracted state through the extended state and back to the retracted state.

[0035] FIG. 10 is an enlarged cross-sectional view of the vicinity of the joint portion between the ballpoint pen refill 3a and the slider 4. As described above, the cam cylinder 5 is a member whose forward and backward movement is restricted inside the barrel 2, and in this embodiment, it is arranged so that it cannot move forward and backward. Ribs 2bb extending in the forward and backward directions are provided on the inner wall surface of the rear barrel 2b. Four ribs 2bb are provided at equal intervals in the circumferential direction. When the barrel 2 is assembled, the front end surface of each rib 2bb and the rear end surface of the front barrel 2a abut against both front and rear end surfaces of the cam cylinder 5, and function as steps for clamping the cam cylinder 5. As a result, the cam cylinder 5 is arranged so that it cannot move forward and backward inside the barrel 2. Note that the term "cannot move forward and backward" implies not only a state in which the cam cylinder 5 does not move at all in the forward and backward directions inside the barrel 2, but also a state in which it moves forward and backward by a gap generated by molding tolerances and slight wear during use.

[0036] By disposing the cam cylinder 5 inside the barrel 2 so that it cannot move back and forth, the operation sound of the retraction mechanism is less likely to be generated other than the collision sound between the locking surface 4ba and the protruding locking surface 5ac, which is the operation sound of the cam mechanism, and this is preferable because it allows the ballpoint pen 1 to have a quieter retraction mechanism. In detail, the cam cylinder 5 rotates with the back and forth movement of the ballpoint pen refill 3 and the slider 4, but since the cam cylinder 5 does not move back and forth, it does not collide with any of the inner wall surfaces of the barrel 2, but only with the slider 4. The back and forth movement of the ballpoint pen refill 3 and the slider 4 is performed only by the backward biasing force of the coil spring 6 and the operation of the clip 7 by the user against the biasing force. When the ballpoint pen refill 3 is in a forward state, the user releases his / her hand, especially his / her fingers, from the clip 7, or, while keeping his / her fingers on the clip 7, weakens the forward force from the coil spring 6 to less than the backward biasing force. The ballpoint pen refill 3 and the slider 4 move backward. Whichever method is used to retract the ballpoint pen refill 3 and the slider 4, the retraction mechanism can be operated quietly, which is preferable.

[0037] FIG. 11 is an external perspective view of the slider 4. A sliding groove 4c extending in the front-rear direction is provided on the outer wall surface of the slider 4. Two sliding grooves 4c are provided at equal intervals in the circumferential direction. In addition, of the four ribs 2bb provided on the inner wall surface of the rear shaft 2b, two ribs facing each other in the circumferential direction at the position corresponding to the sliding groove 4c are provided with a sliding rib 2bba extending from the middle in the front-rear direction toward the rear and protruding radially inward from the front end surface. The sliding rib 2bba is inserted into the sliding groove 4c. The front end surface of the sliding rib 2bba abuts against the front end surface of the sliding groove 4c, thereby stopping the retraction of the ballpoint pen refill 3 and the slider 4. In addition, the sliding rib 2bba slides along the sliding groove 4c, so that the slider 4 is arranged in the barrel 2 so as not to be rotatable. As a result, the ballpoint pen refill 3 and the slider 4 are arranged in the barrel 2 so as not to be rotatable. In addition, being unable to rotate does not only mean a state in which the slider 4 does not move at all in the circumferential direction inside the barrel 2, but also a state in which it can rotate in the circumferential direction by the amount of the gap that occurs due to molding tolerances and slight wear during use.

[0038] By disposing the slider 4 inside the barrel 2 so that it cannot rotate, it is possible to prevent loss of force that causes the slider 4 to rotate the cam barrel 5 when the cam mechanism is activated. The cam barrel 5 rotates by converting the forward and backward movement of the slider 4 into a rotational direction, and conversely, the slider 4 receives a considerable reaction force from the cam barrel 5. If the slider 4 rotates backward in the rotational direction due to this reaction force, the force for rotating the cam barrel 5 will be lost, and it will be necessary to move the ballpoint pen refill 3 and the slider 4 forward and backward with even greater force. By preventing such loss of force, the user will no longer need to operate the knock portion with excessive force, which is preferable because it allows the ballpoint pen 1 to have a quieter retractable mechanism.

[0039] An annular protrusion 4d is provided at the front end of the outer wall surface of the slider 4. The rear of the annular protrusion 4d is connected to the front of the locking protrusion 4b. The annular protrusion 4d protrudes radially outward like a brim. When the rear of the slider 4 is inserted from the front of the through hole of the cam cylinder 5, which has a cam portion 5a on its inner wall surface, the front end face of the side wall of the cam portion 5a protruding radially inward finally abuts against the rear end face of the side wall of the annular protrusion 4d. Therefore, the cam cylinder 5 cannot be removed from the front of the slider 4.

[0040] The slider 4 is disposed inside the rear axle 2b. The slider 4 is connected to the clip 7 via the window hole 2ba. The connected portion intersects with the front of the edge that defines the window hole 2ba, so the forward movement of the clip 7 is restricted. Therefore, the slider 4 is also restricted in its forward movement inside the axle tube 2, and cannot be removed from the front end opening of the rear axle 2b.

[0041] Due to this configuration, when a user replaces the ballpoint pen refill 3a due to consumption of ink or a change of ink color, even if the screw engagement between the front shaft 2a and the rear shaft 2b is released, the slider 4 and the cam cylinder 5 will not suddenly fall out of the front end opening of the rear shaft 2b, and the user can easily replace the ballpoint pen refill 3a, which is preferable.

[0042] FIG. 12 is a vertical cross-sectional perspective view of the cam barrel 5. This is a cross-sectional view of the cam barrel 5 in the front-rear direction, and shows the rear of the cam barrel 5 inclined toward the back of the drawing, and the front of the cam barrel 5 inclined toward the front of the drawing. The protruding locking surface 5ac and the retracted guide surface 5ad of the cam portion 5a have different radial heights, and the retracted guide surface 5ad is lower than the protruding locking surface 5ac. From the rear of the protruding locking surface 5ac in the rotation direction, a protrusion having the retracted guide surface 5ad on its front end surface extends forward in the front-rear direction. The protrusion itself is lower in the radial direction than the protruding locking surface 5ac over the front-rear direction, and a rear operating protrusion guide surface 5ae that is continuous with the protruding locking surface 5ac is provided on the radially outer side from the base portion of the protrusion. The rear operating protrusion guide surface 5ae is also a plane that is inclined forward in the front-rear direction as it moves forward in the rotation direction, and backward in the front-rear direction as it moves backward in the rotation direction, like the protruding locking surface 5ac.

[0043] 13 to 16, a detailed description will be given of how the slider 4 is inserted into the through-hole of the cam barrel 5. Similar to Figs. 4 to 9, Figs. 13 to 16 show the slider 4 and the cam barrel 5 expanded in the circumferential direction so that the contact relationship between the slider 4 and the cam barrel 5 can be visually confirmed.

[0044] When the rear of the slider 4 is inserted from the front of the through hole of the cam barrel 5, depending on the circumferential positional relationship between the cam barrel 5 and the slider 4, the operating protrusion 4a may come into contact with the cam portion 5a, or the operating protrusion 4a may not come into contact with the cam portion 5a and may simply enter between the circumferentially adjacent cam portions 5a.

[0045] 13 is a diagram showing a case where the actuating projection 4a comes into contact with the cam portion 5a. The rear of the side wall of the actuating projection 4a is formed by two inclined surfaces, a front guide surface 4ab on the front side in the rotation direction and a rear guide surface 4ac on the rear side in the rotation direction. The front guide surface 4ab is inclined forward in the front-rear direction as it moves forward in the rotation direction and is inclined backward in the front-rear direction as it moves backward in the rotation direction, and is a flat surface that faces the protruding locking surface 5ac and the rear actuating projection guide surface 5ae.

[0046] FIG. 14 is a diagram showing the cam cylinder 5 advanced from the state shown in FIG. 13. The front guide surface 4ab abuts against any surface extending from the protruding locking surface 5ac to the rear actuating projection guide surface 5ae. When the front guide surface 4ab abuts against the protruding locking surface 5ac, the cam cylinder 5 rotates forward in the rotation direction along each other's surfaces as the cam cylinder 5 advances. Here, the radial height at the rear of the side wall of the actuating projection 4a is lower than the radial height of the projection having the recessed guide surface 5ad on its front end surface. In other words, the radial top surface at the rear of the side wall of the actuating projection 4a and the radial top surface of the projection having the recessed guide surface 5ad on its front end surface are sized not to come into contact with each other. As a result, even if the cam cylinder 5 advances and rotates forward in the rotation direction, the rear of the actuating projection 4a does not collide with the front of the projection having the recessed guide surface 5ad on its front end surface. Even if the cam barrel 5 continues to move forward and rotate forward in the rotation direction, the front guide surface 4ab can smoothly come into contact with the rear actuating projection guide surface 5ae. The cam barrel 5 receives a circumferential force from the protruding engagement surface 5ac and the rear actuating projection guide surface 5ae via the front guide surface 4ab, and rotates forward in the rotation direction.

[0047] Here, the radial height of the side wall of the actuating projection 4a is different between the front side where the actuating surface 4aa is provided and the rear side where the front guide surface 4ab and the rear guide surface 4ac are provided, with the front side being higher. This allows the actuator 3 to be smoothly inserted into the through hole of the cam cylinder 5 without the rear side of the side wall of the actuating projection 4a getting caught on the front side of the cam portion 4, while the actuating surface 4aa can abut against the cam portion 4 as described above, allowing it to function as a cam mechanism, which is preferable.

[0048] Fig. 15 is a view showing the cam barrel 5 advanced from the state shown in Fig. 14. When the cam barrel 5 is advanced from the state shown in Fig. 14, the actuation projection 4a is released from contact with the cam portion 5a with which it was in contact when it was in the state shown in Fig. 14. The actuation projection 4a is guided between the cam portion 5a and the cam portion 5a located rearward of the cam portion 5a in the rotation direction. When the cam barrel 5 is advanced further, it reaches the state shown in Fig. 3, and the insertion of the slider 4 into the through hole of the cam barrel 5 is completed.

[0049] Unlike Fig. 13, Fig. 16 is a diagram showing a case where the actuating projection 4a does not abut against the front end surface of the side wall of the cam barrel 5. In the state of Fig. 16, a front actuating projection guide surface 5af is provided in front of the projection of the cam portion 5a that extends furthest forward in the rotation direction, which is the side wall of the cam portion 5a with which the actuating projection 4a abuts. A front actuating projection guide surface 5aa is provided behind the front actuating projection guide surface 5af in the front-rear direction. The rear guide surface 4ac and the front actuating projection guide surface 5af are flat surfaces that face each other and are inclined forward in the front-rear direction as they move rearward in the rotation direction and backward in the front-rear direction as they move forward in the rotation direction.

[0050] When the rear guide surface 4ac and the front actuating projection guide surface 5af come into contact with each other, the cam barrel 5 receives a circumferential force from the rear guide surface 4ac via the front actuating projection guide surface 5af and rotates rearward in the rotation direction. The actuating projection 4a is then guided between the cam portion 5a and the cam portion 5a located forward of the cam portion 5a in the rotation direction, resulting in the same state as shown in FIG. 15. When the cam barrel 5 is further advanced, the state shown in FIG. 3 is reached and the insertion of the slider 4 into the through hole of the cam barrel 5 is completed.

[0051] FIG. 17 is an external view of the clip 7 on the barrel 2 side. The side wall of the clip 7, which is a molded product of polycarbonate resin, is provided with a gate position 7a at the time of molding. A three-pronged rib 7b is provided on the outer wall surface of the clip 7 on the barrel 2 side. The ends of two of the three ribs of the rib 7b sandwich the gate position 7a in the front-to-rear direction, and the remaining rib extends in a direction perpendicular to the front-to-rear direction, with the gate position 7a located on the extension line. The rib 7b acts as a beam to improve the strength of the clip 7, making it resistant to cracking and breaking even when bent, which is preferable.

[0052] FIG. 18 is an external view of the shaft tube 2 side of the clip 7 according to another embodiment. As in FIG. 17, the clip 7 is a molded product of polycarbonate resin. The side wall of the clip 7 is provided with a gate position 7a at the time of molding. The clip 7 has a four-pronged rib 7b on the outer wall surface on the shaft tube 2 side. One of the four ribs of the rib 7b is formed thick in the front-rear direction, and the gate position 7a is designed to fit within the front-rear range. With such a configuration, the thickness near the gate position 7a becomes large, and it is preferable that it is particularly resistant to cracks and breaks starting from the gate position 7a. In general, the thicker the resin molded product is, the more likely it is that so-called sink marks will occur, which are unintentional unevenness on the surface of the molded product, as the gate position 7a where the resin flows into the mold is located at the location where the thickness of the clip 7 becomes large. This is preferable because a sufficient amount of resin is filled in the location, and sink marks are less likely to occur. Furthermore, since this embodiment has one more rib extending in a direction perpendicular to the front-rear direction than the rib 7b in FIG. 17, the strength of the clip 7 in the torsional direction is improved, which is preferable. [Explanation of symbols]

[0053] 1 ballpoint pen 2 shaft cylinder 2a front axle 2aa stepped section 2ab Coil spring front end rib 2b rear axle 2ba window hole 2bb Rib 2bba sliding rib 3 Ballpoint pen refills 3a Ballpoint Pen Tip 3b Pipe 3ba Coil spring rear end protrusion 4 Slider 4a Actuation projection 4aa Working surface 4ab Front guide surface 4ac Rear guide surface 4b Locking protrusion 4ba Locking surface 4c Slide groove 4d annular process 5 Cam barrel 5a Cam section 5aa Front working surface 5ab Rear working surface 5ac protruding locking surface 5ad Immersive Guide 5ae Rear operating protrusion guide surface 5af Front operating protrusion guide surface 6 Coil spring 7 Clips 7a Gate location 7b Rib

Claims

1. an axle tube in which a front axle and a rear axle are detachably connected; A writing instrument body provided inside the barrel; A slider that is provided inside the barrel and is arranged behind the writing instrument body so as not to be rotatable; a cam cylinder rotatably provided on an outer circumferential side of the slider inside the shaft cylinder, the cam cylinder having a through hole through which the slider is inserted; A retractable writing instrument comprising: the writing instrument body is arranged to be movable back and forth by a rearward biasing force of a resilient member and a forward force caused by an operation of a knock portion exposed to the outside of the barrel via the slider arranged at the rear of the writing instrument body, The slider is disposed so as not to be removable from at least the front end opening of the rear axle, a locking protrusion provided on an outer wall surface of the writing instrument body and / or the slider can be switched between an engaged state in which the locking protrusion is in contact with a cam portion provided on the cam cylinder and a released state in which the locking protrusion is released from contact with the cam portion, thereby allowing a writing portion provided at the front end of the writing instrument body to be projected and retracted from an opening at the front end of the barrel, the cam barrel allows only the rear end of the slider to be inserted into the through hole of the cam barrel from a front side, The cam barrel cannot be removed from the front of the slider.

2. 2. The retractable writing implement according to claim 1, wherein a rear end surface of the locking projection and a front end surface of the cam portion are surfaces that are inclined with respect to the front-rear direction and face each other.

3. A retractable writing instrument as described in claim 1 or 2, wherein the slider has an annular protrusion at its front end for restricting the cam barrel from slipping out forward, and the cam barrel cannot be removed from the front of the slider because its forward slippage is restricted by the annular protrusion of the slider.

4. The cam barrel has a plurality of cam portions each having a front operating protrusion guide surface inclined relative to the front-rear direction provided at the rear thereof, The slider has an operating protrusion provided at its rear with a rear guide surface inclined relative to the front-rear direction, When the slider is inserted into the cam barrel, the front actuating projection guide surface provided at the rear of the plurality of cam portions comes into contact with the rear guide surface of the actuating projection, and the cam barrel rotates in the circumferential direction, so that each of the actuating projections is guided between a pair of circumferentially adjacent cam portions among the plurality of cam portions.

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

5. A retractable writing instrument as described in claim 1 or 2, characterized in that the slider is connected to a clip through a window hole in the rear shaft.

Images