JP4575557B2 - Writing instrument shaft - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a writing cylinder. More specifically, the present invention relates to a shaft tube of a writing instrument in which a concave portion is provided on the outer surface of the front portion of a shaft cylinder main body made of synthetic resin injection molding, and a grip portion made of an elastic material is provided in the concave portion. In the present invention, “front” refers to the pen tip side, “rear” refers to the opposite, “outward” refers to the radially outward direction, and “inward” refers to the radial direction. Point inward.
[0002]
[Prior art]
Conventionally, in a writing instrument shaft tube, a concave portion is provided on the outer surface of the front portion of the shaft tube body formed by injection molding of synthetic resin, and a grip portion made of an elastic material is formed in the concave portion by integral molding or attachment of another member. It has been.
[0003]
[Problems to be solved by the invention]
As shown in FIG. 7, the inner surface of the concave portion 91 of the conventional shaft cylinder main body 9 is a surface in which the front end surface 91a and the rear end surface 91b are orthogonal to the axis (that is, a vertical surface). Therefore, when the shaft cylinder main body 9 is obtained by injection molding using a split mold, the convex portion 10 of the concave molding die is formed into a concave portion of the shaft cylindrical main body 9 in the process of opening the mold radially outward. 91, the front end wall 91a or the rear end wall 91b of the inner surface of the recess 91 is scraped and deformed by the convex portion 10 of the mold, and the outer end of the front end wall 91a on the inner surface of the recess 91 (or There is a possibility that a burr 92 may be generated at the outer end portion of the rear end wall 91b of the inner surface of the concave portion 91 (or the outer surface of the rear shaft tube main body 9). This is because the inner surface of the concave portion 91 of the shaft barrel body 9 bites into the convex portion 10 of the mold for molding the concave portion due to shrinkage (particularly in the axial direction) during cooling of the resin of the shaft barrel main body 9. In particular, the bite tends to occur when a continuous cylindrical grip portion (for example, a grip portion having an axial dimension of 10 mm or more) that is long in the axial direction is provided.
[0004]
If the burr 92 is present at the outer end portion of the front end wall 92a or the outer end portion of the rear end wall 92b of the inner surface of the recess 91 of the shaft tube main body 9, an appearance defect of the shaft tube main body 9 occurs. At the same time, the finger hits the burr 92 at the time of writing, which is uncomfortable. Further, in a type in which a cylindrical grip portion made of an elastic material, which is a separate member from the shaft tube main body 9, is attached to the recess 91 of the shaft tube main body 9, when the burr 92 is present on the outer surface of the shaft tube main body 9, When the grip portion is attached, the inner surface of the grip portion may be caught by the burr 92 and the grip portion may not be smoothly attached.
[0005]
Further, the grip portion is integrally formed on the outer surface of the shaft tube main body 9 by two-color molding (that is, the shaft tube main body 9 is formed by the primary mold, and then the outer surface of the shaft tube main body 9 is formed by the secondary mold. In the case where the secondary mold is a split mold, the radial misalignment (that is, misalignment) between the shaft cylinder body 9 formed by the primary mold and the secondary mold. ) Occurs, the inner end of the mating surface of the secondary mold and the outer surface of the shaft cylinder main body 9 come into contact with each other when the secondary mold is opened and closed. There is a possibility that protrusions and scratches such as galling may occur on the outer surface of the shaft tube main body 9 behind the 91b. As a result, as in the case of the burr, there is a risk that the appearance of the shaft cylinder will be deteriorated, and that the finger will hit the fray at the time of writing, which may be uncomfortable.
[0006]
The present invention solves the above-mentioned conventional problems, and can smoothly separate the mold (primary mold) from the molded cylinder body, and the outer end of the front end wall of the inner surface of the recess or There is no risk of burring on the outer end of the rear end wall, and when the grip part is formed by two-color molding, the shaft in front of the front end wall of the recess or rearward of the rear end wall when the secondary mold is opened and closed It is an object of the present invention to provide a writing instrument shaft cylinder that is free from galling on the outer surface of the cylinder body.
[0007]
[Means for Solving the Problems]
[1] The present invention includes a shaft cylinder body 2 obtained by injection molding of a synthetic resin using a split mold and having a recess 3 on the front outer surface, and an elastic material provided in the recess 3 of the shaft cylinder body 2. A writing tube shaft 1 having a grip portion 6 and at least one of an outer end portion of the front end wall 4 on the inner surface of the recess portion 3 and an outer end portion of the rear end wall 5 on the inner surface of the recess portion 3. or one, setting the inclined surfaces 41 and 51 so that gradually increases as the axial distance L is directed from the inside in the radial direction outwardly between the front end wall 4 and the rear end wall 5 of the inner surface of the recess 3 The grip portion 6 is integrally provided in the concave portion 3 of the shaft tube main body 2 by two-color molding, and the inclined surfaces 41 and 51 are exposed to the outside (Claim 1). (See FIGS. 1 to 6)
[0008]
(Function)
According to the configuration of the first aspect, in the process of opening the mold outward in the radial direction, the convex part of the concave mold is formed from the front end wall 4 and the rear end wall 5 on the inner surface of the concave part 3 of the shaft cylinder body 2. Therefore, the generation of burrs at the outer end of the front end wall 4 or the outer end of the rear end wall 5 on the inner surface of the recess 3 can be avoided. Thereby, generation | occurrence | production of the external appearance defect of the axial cylinder main body 2 can be suppressed, and the comfortable grip property at the time of writing use can be maintained.
[0009]
[0010]
(Function)
The arrangement of claim 1, in the case of integrally molded by two-color molding in the recess 3 of the barrel body 2 a grip portion 6 is exposed to the outside formed in the outer end portion of the front end wall 4 of the inner surface of the recess 3 The inclined surface 41 or the inclined surface 51 exposed to the outside formed at the outer end of the rear end wall 5 of the inner surface of the concave portion 3 can be used as a close contact surface with the secondary mold. Due to the radial displacement between the shaft cylinder body 2 formed by the mold and the split mold type secondary mold, the inclined surfaces 41 and 51 are caulked when the secondary mold is opened and closed. Even if such protrusions or scratches occur, there is no possibility that protrusions or scratches such as galling will occur on the outer surface of the shaft cylinder body 2 at least in front of the front end wall 4 or rearward of the rear end wall 5 on the inner surface of the recess 3. Therefore, the comfortable gripping property at the time of writing use can be maintained, and galling generated on the inclined surfaces 41 and 51 is not conspicuous, so that the appearance defect of the shaft cylinder main body 2 can be suppressed.
[0011]
[ 2 ] In the shaft tube 1 of the writing instrument according to the first aspect, between the inclined surface 41 of the outer end portion of the front end wall 4 of the inner surface of the recess 3 and the front end wall of the grip portion 6, or the inner surface of the recess 3 It is preferable that a groove-like gap 7 is formed in at least one of the inclined surface 51 at the outer end portion of the rear end wall 5 and the rear end wall of the grip portion 6 (Claim 2 ). (See FIGS. 1 to 4)
[0012]
(Function)
According to the configuration of claim 2 , the protrusions and scratches such as galling are inclined surfaces 41 on the outer end of the front end wall 4 on the inner surface of the recess 3 or inclined surfaces on the outer end of the rear end wall 5 on the inner surface of the recess 3. 51, since the protrusions and scratches such as the galling are present in the groove-shaped gap 7 with the front end wall or the rear end wall of the grip, the protrusions and the scratches such as the galling are further increased. Therefore, it is possible to further prevent the finger from hitting the protrusions and scratches of the galling and the like during writing.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0014]
1 and 2 show an embodiment in which the shaft cylinder 1 of the present invention is applied. The writing instrument 8 of the present embodiment mainly includes a shaft tube 1, a metal tip 81 that is detachably screwed into a front end opening of the shaft tube 1, and the inside of the shaft tube 1 and the tip body 81. And a refill 82 (here, a ballpoint pen refill) accommodated in a replaceable manner.
[0015]
(Refill)
The refill 82 includes a pen tip 83 (here, a ballpoint pen tip), an ink storage tube 84, and a pen tip holder 85 that connects the pen tip 83 and the ink storage tube 84. Inside the ink storage tube 84, there are ink (for example, a water-based gel ink to which shear thinning is applied, or a medium-viscosity oil-based ink), and a grease-like follower that moves forward as the ink is consumed at the rear end of the ink. Is housed. Further, a collar portion 85 a is projected from the outer surface of the nib holder 85.
[0016]
The refill 82 is inserted into the shaft tube main body 2 from the front end opening of the shaft tube 1, and then the front body 81 is screwed into the front end of the shaft tube 1. At this time, the collar portion 85 a of the pen tip holder 85 is sandwiched and fixed in the front-rear direction by the front end edge of the shaft tube main body 2 and the inner surface of the tip body 81, and at the same time, the pen tip 83 is inserted from the tip hole of the tip body 81. It protrudes to the outside.
[0017]
(Shaft tube)
The shaft cylinder 1 includes a shaft cylinder body 2 made of synthetic resin and a grip portion 6 made of an elastic material.
[0018]
(Shaft cylinder body)
The shaft tube main body 2 is obtained by injection molding of synthetic resin, and an annular recess 3 is integrally formed on the outer surface. The concave portion 3 is formed to be relatively long in the axial direction, and specifically, the maximum value of the axial distance L (that is, the outer end of the front end wall 4 and the outer end of the rear end wall 5 on the inner surface of the concave portion 3). The axial distance from the end is set to 25 mm. Further, the front end wall 4 of the inner surface of the recess 3 is an inclined surface that gradually increases in diameter as it goes forward, and the rear end wall 5 of the inner surface of the recess 3 gradually increases in diameter as it goes rearward. It is an inclined surface. The inclined surface α of the front end wall 4 of the inner surface of the recess 3 is set to an inclination angle α of 30 degrees with the surface perpendicular to the axis, and the inclined surface of the rear end wall 5 of the inner surface of the recess 3 is perpendicular to the axis. The formed inclination angle β is set to 30 degrees.
[0019]
(Grip part)
In the annular recess 3 of the shaft cylinder body 2, the grip portion 6 is molded in two colors (that is, after the shaft cylinder body 2 is molded by a split mold primary mold, the shaft is then split by a split mold secondary mold. The grip portion 6 is formed on the outer surface of the tube body 2). The grip portion 6 has a cylindrical shape extending in the axial direction, and is continuously provided from the front end wall 4 to the rear end wall 5 on the inner surface of the recess 3. In addition, the outer diameter of the front portion of the grip portion 6 (excluding the outer end portion of the front end wall) is set to be substantially the same as the outer diameter of the outer surface of the axial tube body 2 in front of the recess 3. The outer diameter of the rear portion (excluding the outer end portion of the rear end wall) is set to be approximately the same as the outer diameter of the outer surface of the shaft main body 2 behind the recess 3.
[0020]
The radially inner portion of the front end wall of the grip portion 6 is in close contact with the inclined front end wall 4 on the inner surface of the recess 3. Further, the outer end portion of the front end wall of the grip portion 6 has an inclined surface that gradually increases in diameter toward the rear (specifically, an inclined surface having an angle of 30 degrees with respect to a vertical plane with respect to the axis), A gap 7 made of an annular groove having a V-shaped cross section is formed between the inclined surface and an inclined surface 41 provided on the outer end portion of the front end wall 4 of the inner surface of the concave portion 3, and the inclined surface The surface 41 is exposed so as to be visible from the outside. The depth in the radial direction of the gap 7 (that is, the radial length of the inclined surface 41 exposed to the outside) is set to 0.1 mm to 0.5 mm.
[0021]
Similar to the front end wall side of the grip portion 6, the radially inner portion of the rear end wall of the grip portion 6 is in close contact with the inclined rear end wall 5 on the inner surface of the recess 3. Further, the outer end portion of the rear end wall of the grip portion 6 has an inclined surface (specifically, an inclined surface having an angle of 30 degrees with respect to the axis perpendicular to the axis) that gradually increases in diameter toward the front. Between the inclined surface and the inclined surface 51 provided at the outer end of the rear end wall 5 of the inner surface of the recess 3, a gap 7 made of an annular groove having a V-shaped cross section is formed. The inclined surface 51 is exposed so as to be visible from the outside. The depth in the radial direction of the gap 7 (that is, the radial length of the inclined surface 51 exposed to the outside) is set to 0.1 mm to 0.5 mm.
[0022]
That is, in the shaft tube 1 of the present embodiment, the front end of the inner surface of the recess 3 is formed on both the outer end of the front end wall 4 on the inner surface of the recess 3 and the outer end of the rear end wall 5 on the inner surface of the recess 3. The inclined surfaces 41 and 51 are provided so that the axial distance L between the wall 4 and the rear end wall 5 gradually increases as it goes from the inside in the radial direction to the outside. Thereby, generation | occurrence | production of the burr | flash by a primary metal mold | die and generation | occurrence | production of the galling by a secondary metal mold | die can be suppressed further.
[0023]
The synthetic resin material constituting the shaft cylinder body 2 is, for example, polypropylene, polyethylene, polycarbonate, polyethylene terephthalate, polyacetal, acrylic, nylon, acrylonitrile / styrene copolymer resin (AS resin), acrylonitrile / butadiene / styrene. Examples thereof include copolymer resins (ABS resins). Moreover, as an elastic material which comprises the said grip part 6, rubber | gum or a thermoplastic elastomer etc. are mentioned, for example.
[0024]
3 to 6 show modifications of the concave portion 3 and the grip portion 6 of the shaft cylinder main body 2.
[0025]
In FIG. 3, the inner part of the front end wall 4 of the inner surface of the recess 3 of the shaft cylinder body 2 is a plane perpendicular to the axis, and the outer end of the front end wall 4 of the inner surface of the recess 3 is forward. It is the inclined surface 41 (inclination angle (alpha) is 45 degree | times) which diameter-expands as it goes. The entire front end wall of the grip portion 6 is a surface perpendicular to the axis, and the inner portion thereof is in close contact with the inner portion of the front end wall 4 on the inner surface of the recess 3. An annular groove is provided between a vertical surface located at the outer end of the front end wall of the grip portion 6 and an inclined surface 41 formed at the outer end of the front end wall 4 of the inner surface of the recess 3. A gap 7 is formed.
[0026]
Further, in FIG. 3, the inner portion of the rear end wall 5 of the inner surface of the recess 3 of the shaft cylinder body 2 is a plane perpendicular to the axis, and the outer end of the rear end wall 5 of the inner surface of the recess 3. However, it is the inclined surface 51 (inclination angle (beta) is 45 degree | times) which diameter-expands as it goes back. Further, the rear end wall of the grip portion 6 is entirely vertical to the axis, and its inner portion is in close contact with the inner portion of the rear end wall 5 on the inner surface of the recess 3. An annular groove is formed between a vertical surface located at the outer end of the rear end wall of the grip portion 6 and an inclined surface 51 formed at the outer end of the rear end wall 5 of the inner surface of the recess 3. A gap 7 is formed. Other configurations are the same as those in FIGS. 1 and 2.
[0027]
4, the front end wall 4 of the inner surface of the concave portion 3 of the shaft tube main body 2 is an inclined surface (inclination angle α is 30 degrees) that gradually increases in diameter toward the front as in FIG. The inner portion of the front end wall is in close contact with the inner portion of the front end wall 4 on the inner surface of the recess 3 as in FIG. 2, and the outer portion of the front end wall of the grip portion 6 faces rearward as in FIG. Accordingly, the inclined surface gradually increases in diameter (specifically, an inclined surface having an angle of 30 degrees with respect to the axis perpendicular to the axis). Thereby, an annular V-shaped cross section is formed between the inclined surface 41 provided at the outer end of the front end wall 4 of the inner surface of the recess 3 and the inclined surface provided at the outer portion of the front end wall of the grip 6. A gap 7 made of a groove is formed.
[0028]
In FIG. 4, the rear end wall 5 of the inner surface of the recess 3 of the shaft tube main body 2 is an inclined surface 51 (inclination angle β is 30 degrees) that gradually increases in diameter toward the rear as in FIG. 2, the inner part of the rear end wall of the grip part 6 is in close contact with the inner part of the rear end wall 5 of the inner surface of the recess 3, and the outer part of the rear end wall of the grip part 6 is Similar to 2, the inclined surface gradually increases in diameter toward the front (specifically, an inclined surface having an angle of 30 degrees with respect to the vertical surface with respect to the axis). Thereby, a V-shaped cross section is provided between the inclined surface 51 provided at the outer end of the rear end wall 5 of the inner surface of the recess 3 and the inclined surface provided at the outer portion of the rear end wall of the grip 6. A gap 7 made of an annular groove is formed.
[0029]
4 is different from FIG. 2 in that the outer diameter of the front portion of the grip portion 6 is set to be larger than the outer diameter of the outer surface of the shaft cylinder body 2 in front of the concave portion 3 and the outer diameter of the rear portion of the grip portion 6. However, it is in the point set larger than the outer diameter of the outer surface of the axial cylinder main body 2 behind the recessed part 3, and the other structure is the same as that of FIG.1 and FIG.2.
[0030]
In FIG. 5, the front end wall 4 of the inner surface of the recess 3 of the axial tube body 2 is an inclined surface (inclination angle α is 30 degrees) that gradually increases in diameter as it goes forward, as in FIG. The entire front end wall is in close contact with the inner portion of the front end wall 4 on the inner surface of the recess 3. On the other hand, the rear end wall 5 of the inner surface of the recess 3 of the shaft cylinder main body 2 is an inclined surface (inclination angle β is 30 degrees) that gradually increases in diameter as it goes rearward, and the entire rear end wall of the grip portion 6. Is in close contact with the inner part of the rear end wall 5 of the inner surface of the recess 3.
[0031]
In FIG. 5, the grip portion 6 is buried in the recess 3, and at least the front end portion of the grip portion 6 has an outer diameter smaller than the outer surface of the shaft cylinder body 2 in front of the recess 3, and the grip portion The rear end of 6 has an outer diameter smaller than the outer surface of the barrel body 2 behind the recess 3. Therefore, at least the inclined surface 41 at the outer end of the front end wall 4 on the inner surface of the recess 3 and the inclined surface 51 at the outer end of the rear end wall 5 on the inner surface of the recess 3 are exposed to the outside. Other configurations are the same as those in FIGS. 1 and 2.
[0032]
In FIG. 6, the front end wall 4 of the inner surface of the recess 3 of the shaft cylinder body 2 is an inclined surface (inclination angle α is 30 degrees) that gradually increases in diameter toward the front as in FIG. 6, the outer surface of the shaft tube main body 2 in front of the recess 3 and the outer surface of the front portion of the grip portion 6 have substantially the same outer diameter. On the other hand, the rear end wall 5 of the inner surface of the concave portion 3 of the barrel body 2 is an inclined surface (inclination angle β is 30 degrees) that gradually increases in diameter as it goes backward as in FIG. The outer surface of the shaft tube main body 2 behind the concave portion 3 and the outer surface of the front portion of the grip portion 6 have substantially the same outer diameter. That is, this is a type in which the gap 7 is not provided in FIG. 2, and at least the mold (primary mold) can be smoothly separated from the molded cylinder body 2, and the front end wall on the inner surface of the recess 3. 4 is formed on the outer end portion (inclined surface 41) of the front end 4 or the outer surface of the shaft tube main body 2 in front thereof, or on the outer end portion (inclined surface 51) of the rear end wall 5 or on the outer surface of the shaft tube main body 2 behind it. There is no risk. Other configurations are the same as those in FIGS. 1 and 2.
[0033]
In the present invention, the inclined surfaces 41 and 51 may be curved surfaces (that is, convex curved surfaces or concave curved surfaces) instead of the flat surfaces as in the above-described embodiment.
[0034]
In the present invention, it is preferable that the inclination angles α and β (that is, angles formed with respect to the axis perpendicular to the axis) of the inclined surfaces 41 and 51 are within 60 degrees (preferably within 45 degrees). Thereby, at the time of writing, it can prevent that the front-end part or rear-end part of the grip part 6 turns up, or the grip part 6 shifts | deviates to an axial direction. Because, when the inclination angle α is larger than 60 degrees, the front end portion or the rear end portion of the grip portion 6 is thin, and the front end portion or the rear end portion of the grip portion 6 is turned up or the axis of the grip portion 6 is used during writing. This is because there is a possibility that a deviation in direction occurs.
[0035]
In the present invention, the maximum value of the axial distance L between the front end wall 4 and the rear end wall 5 on the inner surface of the recess 3 (that is, the outer end and the rear end of the front end wall 4 on the inner surface of the recess 3). The axial distance from the outer end of the wall 5 is preferably 10 mm or more. Because, when the axial distance is smaller than 10 mm, when the concave portion 3 is formed in the axial tube main body 2 by the primary mold, the axial contraction amount at the time of cooling the concave portion 3 of the axial tube main body 2 is small. This is because the inner surface of the concave portion 3 of the barrel main body 2 is weak against the convex portion of the mold for molding the concave portion, and burrs are less likely to occur.
[0036]
In the present invention, the outer surface of the grip portion 6 can be provided with irregularities for the purpose of improving the anti-slip effect.
[0037]
【The invention's effect】
According to claim 1, it is possible to prevent the occurrence of burrs at the outer end portion of the front end wall or the outer end portion of the rear end wall of the inner surface of the concave portion, thereby suppressing the occurrence of poor appearance of the shaft cylinder main body, and Comfortable grip when using writing can be maintained.
[0038]
According to claim 1 , even when the shaft cylinder body is squeezed when the secondary mold is opened and closed in two-color molding, at least the front surface of the inner surface of the concave portion is squeezed on the outer surface of the shaft cylinder body in front of the front end wall or the rear end wall. There is no fear. Therefore, the appearance defect of the shaft cylinder main body can be suppressed, and the comfortable gripping property during writing can be maintained.
[0039]
According to claim 2 , even when galling occurs at the outer end of the front end wall of the inner surface of the recess or the outer end of the rear end wall of the inner surface of the recess when the secondary mold is opened and closed in the two-color molding Is not conspicuous and there is no risk of poor appearance, and furthermore, it is possible to further avoid the finger from hitting the scissors during writing.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
FIG. 2 is an enlarged view of a portion A in FIG.
FIG. 3 is an enlarged view showing a modification of part A in FIG. 1;
FIG. 4 is an enlarged view showing a modified example of part A in FIG. 1;
FIG. 5 is an enlarged view showing a modified example of part A in FIG. 1;
6 is an enlarged view showing a modification of the A part in FIG. 1. FIG.
FIG. 7 is an enlarged vertical sectional view of a main part for explaining a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shaft cylinder 2 Shaft cylinder main body 3 Recessed part 4 Front end wall 41 Inclined surface 5 Rear end wall 51 Inclined surface 6 Grip part 7 Gap 8 Writing tool 81 Tip body 82 Refill 83 Pen tip 84 Ink storage pipe 85 Pen tip holder 85a collar part 9 Axis Cylinder body 91 Concave portion 91a Front end wall 91b Rear end wall 92 Burr 10 Mold convex portion L Axial distance α between front end wall and rear end wall of concave inner surface α Inclination angle β Inclination angle

Claims (2)

A shaft cylinder of a writing instrument comprising a shaft cylinder body obtained by injection molding of a synthetic resin using a split mold and having a recess on the outer surface of the front part, and a grip portion made of an elastic material provided in the recess of the shaft cylinder body And at least one of the outer end of the front end wall of the inner surface of the recess and the outer end of the rear end wall of the inner surface of the recess, the front end wall and the rear end wall of the inner surface of the recess only set an inclined surface so that gradually increases as the axial distance toward the radially inward outward between, provided integrally by two-color molding the grip portion in the recess of the barrel body, outside said inclined surface It is exposed to a shaft of a writing instrument. Between the inclined surface of the outer end portion of the front end wall of the inner surface of the recess and the front end wall of the grip portion, or the inclined surface of the outer end portion of the rear end wall of the inner surface of the recess and the rear end wall of the grip portion The shaft cylinder of a writing instrument according to claim 1, wherein a groove-like gap is formed in at least one of the two.

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