JP3789547B2 - Cap back insertion mating structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a back insertion fitting structure for a writing instrument. Specifically, the present invention relates to a cap rearward fitting structure in which a cap formed by attaching an inner cylinder made of a synthetic resin to the inside of an outer cylinder is fitted to the tail end portion of the shaft cylinder.
[0002]
[Prior art]
Conventionally, in this type of cap rear-end fitting structure, for example, Japanese Utility Model Publication No. 59-14237 discloses a cylindrical member (inner cylinder of the present invention) inside a cap cylinder (corresponding to the outer cylinder of the present invention). And a plurality of protruding bulges (corresponding to the protrusions of the present invention) are formed on the inner surface near the free end of the cylindrical member at appropriate intervals on the circumference. A configuration is disclosed in which an annular ridge (corresponding to the annular recess of the present invention) with which the bulging portion gets over and engages is formed at the tail end of the shaft cylinder.
[0003]
In the structure of Japanese Utility Model Publication No. 59-14237 (see FIG. 7), when a strong pushing force is applied when the cap is inserted backward into the tail end of the shaft cylinder, the convex portion 81a on the inner surface of the inner cylinder 8a is There is a risk that the contact wall 5a on the front side of the annular recess 2a will be overcome and the inner diameter of the projection 81a will be plastically deformed beyond the elastic deformation limit and spread. In particular, this is likely to occur when the contact wall 5a on the front side of the annular recess 2a is an inclined surface. If the convex portion 81a inner diameter is greatly plastically deformed in the direction of expansion, the fitting force between the convex portion 81a and the annular concave portion 2a (the fitting force on the tail end side or the pen tip side) becomes loose, and the cap falls off. It is easy to cause.
[0004]
In addition, in Japanese Utility Model Publication No. 3-31583, an internal fitting (corresponding to the inner cylinder of the present invention) is mounted in a cap body (corresponding to the outer cylinder of the present invention). Is closely attached to the inner surface of the cap body, and further, on the inner surface of the opening end of the inner fitting body, a hook projection (corresponding to the annular recess of the present invention) and a locking projection (removable projection of the present invention). A cap back-fitting structure provided with a protrusion) is disclosed.
[0005]
In the structure of the Japanese Utility Model Publication No. 3-31583, the outer peripheral surface of the inner cylinder in the vicinity of the convex portion is in close contact with the inner peripheral surface of the outer cylinder, so that the convex portion is fitted into the annular concave portion of the shaft cylinder (or In the process of overriding and fitting, the cap is not expanded and deformed, and the protrusion is not damaged by a small number of times of attaching and detaching the cap, so that there is a possibility that proper fitting force cannot be maintained. In particular, this is likely to occur when the annular recess is made of a hard material such as metal. In addition, as described above, since the outer peripheral surface of the inner cylinder is in close contact with the inner peripheral surface of the outer cylinder, the open end of the inner cylindrical peripheral wall provided with the convex portion is radially outward. It does not elastically deform in the direction, and a feeling of fitting with a good fitting sound (so-called patching sound) at the time of drop fitting cannot be obtained.
[0006]
[Problems to be solved by the invention]
The present invention solves the above-mentioned conventional problems, and when the cap is fitted backward on the tail end of the shaft cylinder, the inner diameter of the convex part of the inner cylinder is greatly expanded or deformed, or the convex part is crushed. Therefore, it is an object of the present invention to provide a cap back-fitting structure that can maintain a proper fitting force over a long period of time and obtain a good fitting feeling. In the present invention, “front side” indicates the pen tip side of the shaft cylinder or the open end side of the cap, while “rear side” indicates the tail end side of the shaft cylinder or the closed end side of the cap. Show.
[0007]
[Means for Solving the Problems]
1. Outline The present invention is a cap back-fitting structure in which a cap 6 formed by attaching an inner cylinder 8 made of synthetic resin to the inside of an outer cylinder 7 is fitted to the tail end portion of the shaft cylinder 1. An annular gap 9 is formed between the outer peripheral surface of the opening end and the inner peripheral surface of the outer cylinder 7, and a convex portion 81 is provided on the inner peripheral surface of the opening end of the inner cylinder 8. An annular concave portion 2 into which the convex portion 81 falls and fits is provided on the outer peripheral surface of the end portion, and a regulating wall 5 on which the front surface of the convex portion 81 is pressed by a cap pushing force is provided in front of the annular concave portion 2. The gap S between the top of the restriction wall 5 and the inner peripheral surface of the outer cylinder 7 when the protrusion 81 is in the fitted state is larger than the radial thickness T of the opening end of the inner cylinder 8. The contact wall 3 of the annular recess 2 where the front surface of the projection 81 is press-contacted when the projection 81 and the annular recess 2 are in the fitted state is inclined. It is a requirement that it is formed in a planar shape .
[0008]
(2) Annular concave part In the above-described configuration, the contact wall 3 of the annular concave part 2 with which the front surface of the convex part 81 presses when the convex part 81 and the annular concave part 2 are in the fitted state may be formed in an inclined surface shape. preferable. In the case where the shape of the abutting wall 3 is an inclined surface in which the convex portion 81 can easily get forward, the above-described configuration (the clearance S between the top of the regulating wall 5 and the inner peripheral surface of the outer cylinder 7 is defined as the inner cylinder 8). The expansion preventing action of the structure set smaller than the thickness T in the radial direction of the opening end of the opening works effectively.
[0009]
Moreover, in the said structure, it is preferable that the annular recessed part 2 (namely, the front side contact wall 3 and the rear side contact wall 4) is formed with a metal material. Thereby, when the convex part 81 falls into the hard annular concave part 2 and is fitted, the soft inner cylinder 8 made of synthetic resin is sufficiently elastically deformed, and a clear fitting feeling accompanied by a fitting sound is reliably obtained. be able to. In addition, it is effective in terms of easy manufacturing that the annular recess 2 is integrally formed on the peripheral wall of the metal shaft cylinder 1 by plastic deformation inward.
[0010]
Further, the outer diameter of the tail end portion of the shaft cylinder 1 behind the annular recess 2 (behind the rear contact wall 4) is set to be slightly larger than the inner diameter of the convex portion 81. Thus, when the convex portion 81 is lowered and fitted into the annular concave portion 2, the convex portion 81 gets over the outer peripheral surface of the tail end portion of the shaft cylinder at the rear of the annular concave portion 2, and then the rear surface of the convex portion 81 is a rear side contact. The cap 6 is surely prevented from falling off by being pressed against the contact wall 4.
[0011]
(3) Restriction wall In the above configuration, the restriction wall 5 is preferably inclined. In the case where the shape of the restriction wall 5 is the inclined surface shape in which the convex portion 81 can easily get forward, the above-described configuration (the clearance S between the top of the restriction wall 5 and the inner peripheral surface of the outer cylinder 7 is defined as the opening of the inner cylinder 8). The effect of preventing the expansion of the structure having a thickness smaller than the wall thickness T in the radial direction of the end works effectively.
[0012]
The restriction wall 5 may be formed in an inclined flat surface continuously forward from the front contact wall 3 (FIGS. 3 and 4), or connected forward from the front contact wall 3 via the step portion 11. (FIG. 5). When the regulation wall 5 is inclined flat, the inclination angle is effectively in the range of 30 to 80 degrees with respect to the axis. Moreover, the said regulation wall 5 should just be an inclined surface, and may be formed in the curved surface shape like FIG. 6 instead of planar shape like FIGS.
[0013]
(4) The convex part 81 is formed integrally on the inner peripheral surface of the opening end (including the vicinity of the opening end) of the inner cylinder 8 in that it is more easily elastically deformed than the closed end side of the inner cylinder 8. Is preferred. The convex portion 81 may have either a configuration formed in an annular shape on the inner peripheral surface of the inner cylinder 8 or a configuration in which a plurality of support projections are dispersed and arranged at regular intervals. When the convex portion 81 is a plurality of support protrusions, the number is suitably about 4-8. In addition, the vertical cross-sectional shape of the convex portion 81 may be any of a front surface and a rear surface such as an R curved surface, a tapered surface, a right-angled surface, and the like, for example, an arc shape, a trapezoidal shape, a square shape, A triangular shape etc. are mentioned.
[0014]
5. Clearance S, wall thickness T
The clearance S between the top of the restriction wall 5 and the inner peripheral surface of the outer cylinder 7 is such that the top of the restriction wall 5 (that is, the end of the restriction wall 5) and the inner peripheral surface of the outer cylinder 7 when the convex portion 81 and the annular recess 2 are fitted. It is defined by the gap. Further, the radial thickness T of the opening end (including the vicinity of the opening end) of the inner cylinder 8 specifically indicates the thickness including the convex portion 81 of the opening end peripheral wall.
[0015]
(6) Since the annular gap 9 is provided between the outer peripheral surface of the open end of the annular gap inner cylinder 8 and the inner circumference surface of the outer cylinder 7, the inner cylinder 8 having the convex portion 81 is provided at the time of drop fitting. The elastic deformation of the opening end peripheral wall in the diameter-enlarging direction is facilitated, and the convex portion 81 easily gets over the outer peripheral surface of the tail end portion of the shaft cylinder 1 behind the annular concave portion 2. Further, the clearance dimension of the annular gap 9 when the convex portion 81 and the annular concave portion 2 are in the fitted state is a limit dimension that the inner diameter of the convex portion 81 can be expanded, and the convex portion 81 gets over the regulation wall 5. Accordingly, the amount of expansion of the inner diameter of the convex portion 81 (that is, the radial distance from the top of the convex portion 81 in the fitted state to the top of the restricting portion 5) is set.
[0016]
(7) The material inner cylinder 8 is made of, for example, a relatively soft synthetic resin material such as polyethylene or polypropylene, and the outer cylinder 7 is made of, for example, aluminum, stainless steel, brass, or white or the like. A hard metal material is effective.
[0017]
(Function)
When the cap 6 is inserted backward into the tail end of the shaft tube 1, the annular gap 9 facilitates elastic deformation in the diameter increasing direction of the opening end peripheral wall of the inner tube 8 provided with the convex portion 81, and the fitting sound To get a good and clear fit.
[0018]
When the cap 6 is fitted to the tail end portion of the shaft cylinder 1 (FIG. 3), the convex portion 81 on the inner peripheral surface of the inner cylinder 8 of the cap 6 is fitted into the annular concave portion 2 of the shaft cylinder 1 by being lowered. . At this time, the front surface of the convex portion 81 is pressed against the front contact wall 3, and at the same time, the rear surface thereof is pressed against the rear contact wall 4.
[0019]
Further, when the cap 6 is pushed into the tail end of the shaft cylinder 1 more strongly than necessary (FIG. 4), the convex portion 81 moves forward along the front contact wall 3 and is pressed against the restriction wall 5 at the same time. The opening end of the inner cylinder 8 is slightly elastically deformed in the diameter increasing direction due to the presence of the annular gap 9, and the outer peripheral surface of the opening end of the inner cylinder 8 is pressed against the inner peripheral surface of the outer cylinder 7. That is, the clearance S between the top of the regulating wall 5 and the inner peripheral surface of the outer cylinder 7 is set to be smaller than the wall thickness T of the opening end peripheral wall of the inner cylinder 8, so that the opening end (convex portion 81) of the inner cylinder 8. ) Over the restriction wall 5 is not inserted into the gap S, and the expansion deformation (plastic deformation) of the inner diameter of the convex portion 81 is reliably suppressed. As a result, the inner diameter and shape of the convex portion 81 (fitting portion) can be properly maintained over a long period of time even if a strong pushing force is applied during the backward insertion of the cap.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0021]
1 to 4 illustrate a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of the first embodiment with the cap inserted backward, FIG. 2 is a longitudinal sectional view of the tail end portion of the shaft cylinder with the cap of FIG. 1 removed, and FIG. FIG. 4, which is an enlarged vertical sectional view of the part, is an enlarged sectional view when the cap pushing force of FIG.
[0022]
(Shaft tube)
The shaft cylinder 1 is made of an aluminum thin-walled cylindrical body (thickness 0.5 mm). The peripheral wall of the tail end portion of the shaft cylinder 1 is deformed inward in a circular shape at one place by pressing a roller inward from the radially outer side (by rolling). Thereby, an annular recess 2 that is recessed radially inward is integrally formed on the outer peripheral surface of the inwardly deformed portion. Further, an annular recess 2 into which the protrusion 81 can be fitted is formed on the outer peripheral surface of the shaft tube 1 on the pen tip side. In addition, a ballpoint pen refill is accommodated inside the shaft cylinder 1 and its pen tip projects outside from the front end of the shaft cylinder 1.
[0023]
(Annular recess)
As shown in FIG. 3, the annular concave portion 2 is inclined so that the front surface of the inclined flat contact surface 3 is pressed against the front surface of the convex portion 81 and the rear surface of the convex portion 81 is in pressure contact with the convex portion 81. And a flat rear contact wall 4. The front contact wall 3 continuously extends forward and constitutes an inclined regulation wall 5. The angle of the restriction wall 5 is set to 45 degrees with respect to the axis.
[0024]
(cap)
The cap 6 includes an outer cylinder 7 and an inner cylinder 8. Specifically, an outer cylinder 7 made of a metal (for example, aluminum) thin-bottomed cylinder with a metal clip 71 fixed to the outer surface, and a synthetic resin (for example, made of polyethylene) attached to the inside of the outer cylinder 7 ) Inner cylinder 8.
[0025]
(Inner cylinder)
The inner cylinder 8 is fixed inside the outer cylinder 7 via a metal (for example, brass) mounting ring 73. The outer peripheral surface of the mounting ring 73 is fixed to the inner wall of the outer cylinder 7 on the closing side, while the inner peripheral surface is fitted into the annular groove on the outer periphery of the top of the inner cylinder 8. Further, a pen point seal member 72 made of synthetic rubber is attached to the inner peripheral surface of the top portion of the inner cylinder 8 by press fitting. The nib seal member 72 is brought into close contact with the ball at the nib of the ball-point pen tip when the cap 6 is attached to the nib side of the barrel 1.
[0026]
(Convex)
Four hemispherical convex portions 81 are integrally provided on the inner peripheral surface of the open end of the inner cylinder 8 at equal intervals. The convex portion 81 is fitted into the annular concave portion 2 of the shaft tube 1 when the cap is inserted backward.
[0027]
(Gap S, wall thickness T)
The convex portion 81 is formed in a hemispherical shape, and its radial thickness T is set to 0.775 mm. On the other hand, the clearance dimension S between the top of the regulating wall 5 and the inner peripheral surface of the outer cylinder 7 is set to 0.35 mm. That is, since the gap S is set smaller than the wall thickness T (since the relationship of S <T is satisfied), even if a strong pushing force is applied, the convex portion 81 can get over the annular concave portion 2. In other words, the inner diameter of the opening end of the inner cylinder 8 (that is, the diameter of a virtual inscribed circle in contact with the apex of the convex portion 81) is prevented from being expanded. In other words, the regulation wall 5 and the inner peripheral surface of the shaft cylinder 1 both function together to function as a stopper for the cap mounting direction.
[0028]
FIG. 5 shows a second embodiment of the present invention. An alternate long and two short dashes line indicates a state of the inner cylinder 8 opening end (mainly the convex portion 81) when a strong pushing force is applied. This is a modification corresponding to the A portion of FIG. 1 of the first embodiment, and the inclined flat regulation wall 5 is connected forward from the front contact wall 3 via a slight step portion 11. . Further, the hemispherical convex portion 81 is provided on the inner peripheral surface near the opening end of the inner cylinder 8. In the above configuration, the axial movement distance until the opening of the inner cylinder 8 opening end is suppressed is increased by the amount of the stepped portion 11, but the effect of suppressing the opening of the inner cylinder 8 opening end is increased. Is no different from the first embodiment.
[0029]
FIG. 6 shows a third embodiment of the present invention. An alternate long and two short dashes line indicates a state of the inner cylinder 8 opening end (mainly the convex portion 81) when a strong pushing force is applied. This is a modification corresponding to part A of FIG. 1 of the first embodiment, and the front contact wall 3, the rear contact wall 4 and the regulation wall 5 of the annular recess 2 are curved (concave curved or Convex curved surface). In the configuration of the annular recess 2 and the regulation wall 5, the effect of suppressing the opening of the inner cylinder 8 opening end is no different from that of the first embodiment.
[0030]
【The invention's effect】
With the above-described configuration, the cap back-fitting structure of the present invention is such that when the cap is back-fitted to the tail end of the shaft tube, the inner diameter of the convex portion of the inner cylinder is greatly expanded or deformed, or the convex portion is crushed. In addition, a proper fitting force can be maintained over a long period of time, and a good and clear fitting feeling can be obtained.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a first embodiment of the present invention when a cap is inserted backward.
FIG. 2 is a longitudinal sectional view of a tail end portion of a shaft cylinder with a cap of FIG. 1 removed.
FIG. 3 is an enlarged vertical sectional view of a part A in FIG.
4 is an enlarged cross-sectional view of a part A when the cap pushing force in FIG. 1 is greatly applied. FIG.
FIG. 5 is an enlarged vertical sectional view of a main part of a second embodiment.
FIG. 6 is an enlarged vertical sectional view of a main part of a third embodiment.
FIG. 7 is an enlarged vertical sectional view of a main part of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Shaft cylinder 11 Step part 2 Annular recessed part 3 Front side abutting wall 4 Rear side abutting wall 5 Restriction wall 6 Cap 7 Outer cylinder 71 Clip 72 Nib seal member 73 Mounting ring 8 Inner cylinder 81 Protruding part 9 Annular gap S Gap T Thickness

Claims (2)

A cap rearward fitting structure in which a cap (6) formed by attaching an inner cylinder (8) made of synthetic resin to the inside of the outer cylinder (7) is fitted to the tail end portion of the shaft cylinder (1), An annular gap (9) is formed between the outer peripheral surface of the open end of the inner cylinder (8) and the inner peripheral surface of the outer cylinder (7), and a convex portion ( 81), and on the other hand, an annular recess (2) into which the projection (81) falls and fits is provided on the outer peripheral surface of the tail end of the shaft cylinder (1), and a cap is provided in front of the annular recess (2). A restriction wall (5) is provided in which the front surface of the convex part (81) is pressed by a pressing force, and the annular concave part (2) and the convex part (81) are in a fitted state. said outer cylinder and the top (7) a gap between the inner circumferential surface (S), is set smaller than the thickness in the radial direction of the open end (T) of the inner tube (8), the convex portion (81) cyclic Part (2) convex portion when the is in the fitted state (81) a cap behind feed the front is equal to or formed on the inclined surface shape of the contact wall (3) of the annular recess (2) for pressing Mating structure. The cap back-fitting structure according to claim 1, wherein the regulating wall (5) is inclined.

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