JP2023035916A - Retractable writing instrument - Google Patents

Abstract

To provide a retractable writing instrument in which a breech plug can be stably attached to the rear end opening of a barrel in order to solve the problem that in the retractable writing instrument disclosed in JP 2019-116038A, the edge forming the window hole may open in the circumferential direction due to molding, and thus the positional relation between the locking portion and the locked portion is deviated, and the mounting operation of the breech plug becomes unstable.SOLUTION: There is provided a retractable writing instrument in which a clamping protrusion consisting of at least two projections is provided in an insertion portion in front of a breech plug, and a notch portion formed by connecting an edge forming a rear end opening of a barrel and an edge forming a window hole is provided. An inner wall surface of the barrel is provided with a clamped protrusion that is circumferentially clamped by the clamping protrusion, straddling the edge forming the window hole connected to the notch portion in the circumferential direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a so-called retractable writing instrument in which a writing instrument body having a writing part at the front end is arranged in a barrel so that it can move back and forth, and the writing part can be projected and retracted from the front end opening of the barrel. The present invention relates to a retractable writing instrument having a structure in which a tail plug is attached to a rear end opening of a barrel. Hereinafter, the direction in which the writing unit protrudes is defined as the front, and the direction in which the writing unit is retracted is defined as the rear. A state in which the writing section protrudes from the front end opening of the barrel so that writing is possible is defined as a projected state, and a state in which the writing section is retracted into the barrel is defined as a recessed state.

2. Description of the Related Art Conventionally, retractable writing instruments are known in which an opening is provided at the rear end of a barrel so that a member such as a writing lead can be arranged inside the barrel. The opening generally has a structure in which a tail plug is attached to the opening so that the members placed inside do not drop off or damage the appearance when the retractable writing instrument is transported or used.

For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2019-116038), a locking portion protruding radially outward is provided at the rear end opening of the barrel, and a locked portion protruding radially inward is provided at the tail plug. A retractable writing instrument is disclosed in which a tail plug is attached to a rear end opening of a barrel barrel by providing a portion, and when the tail plug is attached, the locking portion climbs over the locked portion.

JP 2019-116038 A

The retractable writing instrument disclosed in Patent Document 1 has a window hole extending forward in the longitudinal direction of the barrel from the edge forming the rear end opening of the barrel to the side wall of the barrel. The edge forming the window hole may open in the circumferential direction due to shrinkage or the like after molding. Therefore, there is a problem that the positional relationship between the locking portion and the locked portion is deviated, and the mounting operation of the breech plug becomes unstable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a writing instrument in which a tail plug can be stably attached to the rear end opening of a barrel.

In the present invention, a writing instrument body having a writing part at the front end thereof is arranged in a barrel so as to be movable back and forth, an actuator is arranged at the rear end of the writing instrument body, and the inside of the barrel and the barrel are arranged on the side wall of the barrel. A window hole extending in the front-rear direction is provided through the outside, and a part of the actuator is exposed to the outside of the shaft cylinder through the window hole. A retractable writing instrument that can be retracted from a part, wherein a tail plug is attached to the rear end opening of the barrel, and an insertion part is provided in front of the tail plug to be inserted into the rear end opening of the barrel. is provided with a clamping protrusion consisting of at least two protrusions, and a notch formed by connecting the edge forming the rear end opening of the barrel and the edge forming the window hole is provided, A first gist of a retractable writing instrument in which a clipped projection that is circumferentially clamped by a clamping projection is provided on an inner wall surface of a barrel, straddling an edge forming a window hole connected to a notch in the circumferential direction. and A second aspect of the present invention is a retractable writing instrument in which the front end of the holding projection is the front end of the insertion portion.

In the writing instrument of the present invention, since the clamping protrusion can circumferentially clamp the clamped protrusion provided across the edge forming the window hole connected to the notch in the circumferential direction, the edge forming the window hole can be clamped. It is possible to prevent the portion from opening in the circumferential direction, and the tail plug can be stably attached to the rear end opening of the barrel. In the second aspect, during the installation work, the clamping projection of the breech plug can be brought into contact with the barrel first, and is connected to the notch substantially at the same time as the installation work is started. It is possible to prevent the edge forming the window hole from opening in the circumferential direction, and the tail plug can be stably attached to the rear end opening of the barrel.

External view of ballpoint pen 1 A-A' line cross-sectional view in FIG. External view of the writing instrument main body 3 (a) External view of rear axle 2b, (b) Cross-sectional view taken along line B-B' in Fig. 4(a) External perspective view of rear axle 2b Appearance perspective view of the tail plug 7 Sectional view of the state where the tail plug 7 is attached to the rear end opening 2bb Appearance perspective view of cushioning material 4 Appearance perspective view of partition member 5 Longitudinal cross-sectional view of partition member 5 Front enlarged view of longitudinal section of rear axle 2b Enlarged view of part C in FIG.

The present invention is a writing instrument such as a ballpoint pen, a mechanical pencil, a calligraphy pen, a felt pen, a marking pen, etc., and can be implemented as a retractable writing instrument in which a writing part such as a ballpoint pen tip can be retracted from the front end opening of the barrel. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an external view of a ball-point pen 1, which is a retractable writing instrument according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line A-A' of FIG. The ball-point pen 1 includes three writing instrument bodies 3, a cushioning member 4, a partitioning member 5, and a coil spring 6 as an elastic member arranged inside a hollow cylindrical barrel 2. As shown in FIG.

FIG. 3 is an external view of the writing instrument main body 3. As shown in FIG. A ball-point pen 1 is a multi-core retractable writing instrument in which three writing instrument bodies 3 are arranged inside a barrel 2 . The writing instrument main body 3 is constructed by arranging an actuator 3ba or a clip actuator 3bb at the rear end of a ball-point pen refill 3a having a ball-point pen tip 3aa as a writing part at the front end. Of the three writing instrument bodies 3, two have a ball-point pen refill 3a with an actuator 3ba (Fig. 3(a)), and the remaining one has a ball-point pen refill 3a with a clip actuator 3bb (Fig. 3 (a)). b)). A clip 3bc is attached to the clip actuator 3bb.

The barrel 2 is composed of a front shaft 2a and a rear shaft 2b. The rear portion of the front shaft 2a is inserted through the front open end of the rear shaft 2b. Threaded portions are provided on the rear outer wall surface of the front shaft 2a and the front inner wall surface of the rear shaft 2b, respectively, so that the front shaft 2a and the rear shaft 2b can be coupled by screwing. By releasing the screw engagement, the writing instrument main body 3 can be easily arranged and replaced.

The front shaft 2a is a so-called two-color molded product, and the primary side located radially inside the front shaft 2a is made of polypropylene resin, and the secondary side located radially outside of the front shaft 2a is made of thermoplastic elastomer. The outer wall surface of the front shaft 2a is satin-finished and functions as a grip that can be easily gripped by the user's hand.

The front shaft 2a can be configured in a desired shape by a known method other than the two-color molded product as in this embodiment. It is also possible to configure the grip as a separate member so as to cover the outer wall surface of the front shaft 2a.

Other materials for the front shaft 2a include polycarbonate resin, acrylic resin, polyethylene resin, polyamide resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polyethylene naphthalate resin, and chloride resin, in consideration of moldability and durability. Vinyl resin, ethylene vinyl alcohol copolymer, polyacrylonitrile resin, fluororesin, polyacetal resin, polyethylene terephthalate resin, polystyrene resin, ABS resin, silicone resin, elastomer, composite material containing these resins, etc. can be done. Further, the molding method is not limited to two-color molding as in this embodiment, and various known methods can be appropriately selected.

4(a) is an external view of the rear barrel 2b, FIG. 4(b) is a sectional view taken along the line B-B' of FIG. 4(a), and FIG. 5 is an external perspective view of the rear barrel 2b. A rear side wall of the rear axle 2b is provided with a window hole 2ba extending in the front-rear direction and passing through the inside and outside of the rear axle 2b. The window holes 2ba are provided in the same number as the writing instrument main body 3, and are provided at three locations in the present embodiment. A part of the operating element 3ba and the clip operating element 3bb are exposed to the outside of the shaft tube 2 through the window hole 2ba. A clip 3bc can be attached to the part of the clip actuator 3bb exposed to the outside of the shaft tube 2 . When the part of the actuator 3ba exposed outside the barrel 2 and the clip 3bc are operated from the rear to the front along the window hole 2ba, the writing instrument main body 3 moves forward inside the barrel 2 in conjunction.

The writing instrument main body 3 is urged rearward by a coil spring 6 . The front end of the coil spring 6 is in contact with the rear end surface of the partition member 5 arranged so as not to move back and forth inside the barrel 2 . The rear end of the coil spring 6 is provided in front of the operating element 3ba and the clip operating element 3bb and is in contact with the stepped portion. The coil spring 6 is sandwiched between the partition member 5, the operating element 3ba, and the clip operating element 3bb in a contracted state from the natural state, and constantly biases the writing instrument main body 3 rearward.

When the actuator 3ba (or clip 3bc) is operated to advance the writing instrument main body 3, the shoulder portion 3baa (or shoulder portion 3bba) of the actuator 3ba (or clip actuator 3bb) is provided inside the rear barrel 2b. The ball-point pen tip 3aa protrudes from the front end opening of the front barrel 2a. The shoulder portion 3baa and the shoulder portion 3bba protrude in the chord direction within the cylindrical rear barrel 2b, and engage with the front end portion of the gripped protrusion 2bd that is adjacent to one writing instrument main body 3 in the circumferential direction. Become.

When one of the writing instrument main bodies 3 is in a protruded state, and the other operating element 3ba (or clip 3bc) in the retracted state is operated and advanced, the operating element 3ba (or clip 3bc) of the writing instrument main body 3 in the protruding state, The advanced actuator 3ba (or clip 3bc) abuts. Then, the actuator 3ba (or clip 3bc) of the writing instrument main body 3 in the projecting state is unlocked from the gripped projection 3bd, and the ballpoint pen tip 3aa of the writing instrument main body 3 in the projecting state is inserted into the barrel 2. Immerse yourself. Through the series of operations described above, the user can select an arbitrary writing instrument main body 3 and use the ballpoint pen 1 for writing.

6 is an external perspective view of the tail plug 7. FIG. A rear end opening 2bb as a rear end opening of the barrel 2 is provided at the rear end of the rear shaft 2b. Each writing instrument main body 3 can be arranged inside the barrel 2 from the rear end opening 2bb. The rear end opening 2bb is closed by attaching the tail plug 7 .

The rear shaft 2b is provided with a notch 2bc formed by connecting an edge forming the rear end opening 2bb and an edge forming the window hole 2ba. Since the notch 2bc is provided, the writing instrument main body 3 with the clip 3bc attached to the clip actuator 3bb can be smoothly inserted from the rear end opening 2bb.

The tail plug 7 is a cylindrical member with a bottom. An insertion portion 7 a is provided in front of the tail plug 7 . The insertion portion 7a is a portion of the tail plug 7 that is inserted from the rear end opening 2bb of the rear shaft 2b. Two window hole projections 7ab are provided on the outer wall surface of the insertion portion 7a. When the insertion portion 7a is inserted into the rear end opening 2bb, each window hole projection 7ab finally engages with the rear end surface of the edge forming each window hole 2ba, preventing the tail plug 7a from falling off rearward. Prevented and installed.

A clamping protrusion 7aa is provided in the insertion portion 7a. Two clamping protrusions 7aa are provided in the insertion portion 7a and extend forward in the front-rear direction.

FIG. 7 is a cross-sectional view of the tail plug 7 attached to the rear end opening 2bb. The composition is viewed from the front, with the tail plug 7 positioned on the back side of the drawing. On the inner wall surface of the rear axle 2b, a clamped protrusion circumferentially clamped by the clamping protrusion 7aa is provided, straddling the edge forming the window hole 2ba connected to the notch 2bc in the circumferential direction. The clamped protrusion 2bd is a protrusion that protrudes from the inner wall surface of the rear shaft 2b and extends in the front-rear direction. The radially inner tip portions of the clamped protrusions 2bd are each bifurcated.

When the insertion portion 7a is inserted from the rear end opening 2bb, the clamping protrusion 7aa clamps the clamped protrusion 2bd in the circumferential direction. Of the two prongs of the radially inner tip portion of the clamped protrusion 2bd, the one closer to the cutout 2bc and the edge forming the window hole 2ba connected to the cutout 2bc is the circumferentially inner side wall of the clamping protrusion 7aa. sandwiched by The edge forming the notch 2bc is spaced apart in the circumferential direction after molding of the rear barrel 2b so that it can be easily opened. 2 are provided straddling the . Accordingly, when the tail plug 7 is attached, the edge forming the window hole 2ba can be prevented from opening in the circumferential direction, and the tail plug 7 can be stably attached to the rear end opening 2bb, which is preferable. When the edge forming the window hole 2ba tries to open in the circumferential direction, the clamping protrusion 7aa clamps the clamped protrusion 2bd in the circumferential direction, which is preferable.

When using the clip actuator 3bb which has a shoulder portion 3ba and is wide in the chord direction of the cylindrical rear barrel 2b as in the present embodiment, the clip actuator 3bb is arranged in the rear barrel 2b. Since the space in which the main body 3 is accommodated and which moves back and forth needs to be wide in the circumferential direction and the chord direction, it is necessary to prevent the edges forming the window holes 2ba from being opened in the circumferential direction by the clamping projections 7aa. is possible and preferable.

Further, the front end of the clamping projection 7aa is located at the frontmost position in the insertion portion 7a and serves as the front end of the insertion portion 7a. As a result, when attaching the tail plug 7 to the rear end opening 2bb, the clamping protrusion 7aa of the insertion portion 7a can be brought into contact with the shaft tube 2 first, and almost at the same time as the attachment work is started. The clamped projection 2bd can be clamped. Therefore, since the attachment strength is generated immediately after the attachment work is started, the tail plug 7 can be stably attached to the rear end opening 2bb, which is preferable.

8 is an external perspective view of the cushioning member 4. FIG. The buffer member 4 is a soft member made of butyl rubber. The cushioning member 4 is composed of an insertion portion 4a extending rearward and a cushioning portion 4b positioned forward. The insertion portion 4a extends rearward from the rear end face of the buffer portion 4b. A space for inserting the insertion portion 4a when attaching the cushioning member 4 is provided inside the insertion portion 7a of the tail plug 7 in the radial direction. The outer wall of the insertion portion 4a is provided with a groove portion 4aa recessed radially inward in the front-rear direction. An internal rib 7ac extending in the front-rear direction is provided on the inner wall surface of the insertion portion 7a of the tail plug 7, which forms a space into which the insertion portion 4a is inserted. It is preferable that the groove portion 4aa extends along the internal rib 7ac so that the cushioning member 4 can be positioned in the circumferential direction, and the ease of assembly is improved.

When each writing instrument main body 3 is moved from the protruding state to the retracted state, when the writing instrument main body 3 moves backward inside the barrel 2 , the rear end of the actuator 3 ba or the clip actuator 3 bb is moved to the front end of the cushioning member 4 . It abuts on a certain buffer portion 4b. Since the cushioning member 4 is soft, the collision noise with the operating element 3ba or the clip operating element 3bb is reduced, which is preferable.

9 is an external perspective view of the partition member 5, FIG. 10 is a longitudinal sectional view of the partition member 5, FIG. 11 is an enlarged front view of a longitudinal section of the rear axle 2b, and FIG. The partitioning member 5 is a member attached inside the barrel 2 . In this embodiment, it is mounted inside the rear axle 2b.

The partitioning member 5 is composed of a rearwardly extending partitioning projection 5a and a forwardly extending cylindrical portion 5b. The partition projection 5a is a projection extending rearward from the rear end surface of the cylindrical portion 5b and having a radial tip divided into three. The tubular portion 5b is provided with a through hole 5ba that penetrates in the front-rear direction and through which the ballpoint pen refill 3a is inserted. In this embodiment, three through-holes 5ba are provided in accordance with the number of writing instrument main bodies 3. As shown in FIG. The front end of each coil spring 6 abuts near the opening of each through hole 5ba on the rear end surface of the cylindrical portion 5b. When the ballpoint pen refills 3a move back and forth inside the barrel 2, they do not interfere with each other in the radial direction due to the inner wall of the through hole 5ba and the side wall of the partition projection 5a. Therefore, the back and forth movement of each ballpoint pen refill 3a becomes smoother, which is preferable.

The outer wall of the cylinder portion 5b is provided with three groove portions 5bb that are recessed radially inward in the front-rear direction at equal intervals in the circumferential direction. When the partitioning member 5 is attached to the inside of the rear axle 2b, the partitioning member 5 is positioned in the circumferential direction by attaching the grooves 5bb along the ribs 2be on the inner wall surface of the rear axle 2b and extending in the front-rear direction. It is possible to improve the assembling performance, which is preferable.

A circumferential protrusion 5bc protruding in the radial direction in the shape of a flange is provided on the outer wall surface of the cylindrical portion 5b. In this embodiment, the circumferential projection 5bc is provided at a position where the rear end surface of the cylindrical portion 5b constitutes the rear end surface of the side wall of the circumferential projection 5bc.

The inner wall surface of the rear shaft 2b is provided with a circumferential groove portion 2bf into which the circumferential projection 5bc can be inserted when the partition member 5 is attached. The circumferential groove portion 2bf is formed of a side wall surface 2bfa, a bottom surface 2bfb along the front-rear direction, and a connecting portion 2bfc thereof. When the circumferential projection 5be is inserted into the circumferential groove portion 2bf, the partitioning member 5 is separated by the side wall surface 2bfa that forms the circumferential groove portion 2bf in the inner wall surface of the rear axle 2b and contacts the circumferential projection 5bc in the front-rear direction. Mounted so that it cannot move back and forth.

A connecting portion 2bfc between the side wall surface 2bfa and the bottom surface 2bfb is a curved surface. When the both ends of the side wall surface 2bfa in the radial direction and the center of the bottom surface 2bfb in the front-rear direction are connected by a straight line, the straight line protrudes radially outward to form a curved surface.

Here, the rear axle 2b is a polycarbonate resin molding. Generally, resin molded products obtained by molding resin with a metal mold are used for each part constituting a writing instrument. For example, in the case of a cylindrical member such as the rear shaft 2b, a cylindrical pin having a smaller diameter than the cavity is inserted and/or arranged in a cavity provided with a cylindrical cavity. A material resin is poured between the cavity and the pin, and when the resin solidifies and the pin is pulled out, the resin becomes a molded product having a desired shape, and a tubular member can be obtained.

In order to form the circumferential groove portion 2bf, a circumferential projection protruding from the outer wall surface of the pin is required. There is a risk that it will come into contact with the inner wall surface on the front end opening side and be scraped off.

In this embodiment, both the front and rear connecting portions 2bfc, which are the directions in which the pin is pulled out, are curved. That is, the outer wall surface of the protruding portion forming the circumferential groove 2bf on the outer wall surface of the pin is also curved in a corresponding shape. As a result, when the pin is pulled out, the contact between the projecting portion and the inner wall surface of the rear axle 2b becomes smooth, and the inner wall surface of the rear axle 2b can be prevented from being scraped off. As a result, it becomes easier to form the rear barrel 2b within a desired size range, which is preferable because the partitioning member 5 can be attached to the rear barrel 2b with a desired strength.

If even one connecting portion 2bfc has a curved surface, the contact between the pin and the inner wall surface of the rear axle 2b can be smoothed accordingly. In this embodiment, the pin is pulled out from the front end opening of the rear axle 2b, but the connecting portion 2bfc (the rear end opening side of the rear axle 2b) farther from the opening is also curved. When the pin is pulled out, the outer wall surface of the protrusion forming the connecting portion 2bfc closer to the front end opening is pulled out while being in contact with the inner wall surface of the rear shaft 2b. It expands outward and then tries to return to its original dimensions. At this time, since the outer wall surface of the projecting portion forming the connecting portion 2bfc farther from the front end opening is curved, the rear shaft 2b comes into contact with the angled portion when returning radially inward. Therefore, it is possible to further suppress the inner wall surface of the rear axle 2b from being scraped, which is preferable.

Other materials for the rear axle 2b include polypropylene resin, acrylic resin, polyethylene resin, polyamide resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polyethylene naphthalate resin, chloride resin, etc., in consideration of moldability and durability. Vinyl resin, ethylene vinyl alcohol copolymer, polyacrylonitrile resin, fluororesin, polyacetal resin, polyethylene terephthalate resin, polystyrene resin, ABS resin, silicone resin, elastomer, composite material containing these resins, etc. can be done.

REFERENCE SIGNS LIST 1 ballpoint pen 2 barrel 2a front barrel 2b rear barrel 2ba window hole 2bb rear end opening 2bc notch 2bd pinched projection 2be rib 2bf circumferential groove 2bfa side wall surface 2bfb bottom surface 2bfc connecting portion 3 writing instrument main body 3a ballpoint pen refill 3aa ballpoint pen tip 3ba Actuator 3baa Shoulder 3bb Actuator for clip 3bba Shoulder 3bc Clip 4 Cushioning member 4a Insertion portion 4aa Groove 4b Cushioning portion 5 Partitioning member 5a Partitioning projection 5b Cylinder 5ba Penetration hole 5bb Groove 5bc Circumferential projection 6 Coil spring 7 Tail Plug 7a Insertion portion 7aa Clamping projection 7ab Window hole projection 7ac Internal rib

Claims (2)

A writing instrument body having a writing part at the front end is arranged in the barrel so as to be movable back and forth, an actuator is arranged at the rear end of the writing instrument body, and the inside and outside of the barrel penetrate through the barrel side wall. A window hole extending in the front-rear direction is provided, and a part of the actuator is exposed to the outside of the barrel through the window hole. The retractable writing instrument has a tail plug attached to the rear end opening of the barrel, and an insertion portion inserted into the rear end opening of the barrel is provided in front of the tail plug, and the insertion portion has at least two A clamping protrusion consisting of a protrusion is provided, and a notch formed by connecting the edge forming the rear end opening of the barrel and the edge forming the window hole is provided, and the inner wall surface of the barrel is provided. (2) a retractable writing instrument provided with a clamped projection that is circumferentially clamped by the clamping projections, straddling the edge forming the window hole connected to the notch in the circumferential direction; 2. The retractable writing instrument according to claim 1, wherein the front end of said clamping projection is the front end of said insertion portion.

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