JP2963849B2 - Shaft mating structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fitting structure for a shaft member such as a synthetic resin tubular cap body and a tail plug of a writing instrument.

[0002]

2. Description of the Related Art In a writing instrument, hollow shafts are often fitted and connected together, such as a synthetic resin barrel and a tail plug, a cap body and a tail plug, or a front shaft and a rear shaft. However, in this case, for example, an inward annular projection is formed at the end opening of the axial cap body, and an annular groove is formed on the outer periphery near the end of the tail plug, and the tail plug is pressed into the cap body. The tail plug is fitted to the cap body by engaging the annular projection with the annular groove using elastic deformation.

[0003]

By the way, a considerable amount of time is required to elastically deform the tail plug so as to press-fit the tail plug into the cap body to engage the annular projection with the annular groove and to connect the shafts together. Since press-fitting is required, press-fitting is performed with mechanical force. That is, one of the shafts is set in a vertical posture in the press-fitting machine, and the other shaft is put lightly on one of the shafts by hand. The body is pressurized with pressure.

Accordingly, after the upper shaft body is lightly inserted on the lower shaft body set in the press-fitting machine and put on the lower shaft body, the time from when the press-fitting head of the press-fitting machine presses the upper shaft body with pressure is applied. Meanwhile, the upper shaft body needs to be stationary with the axis line aligned with the lower shaft body. However, if the upper shaft is inserted lightly into the lower shaft, the upper shaft is not stable, and the upper shaft tilts before press-fitting due to vibration of the press-fitting machine. Or fall.

Therefore, according to the present invention, when the upper shaft is placed on the lower shaft in the vertical position and press-fitted by the press-fitting machine, the upper shaft tilts or falls between the placement and the press-fitting. It is an object of the present invention to provide a shaft body fitting structure that does not have any problem.

[0006]

In order to achieve the above object, according to the present invention, an inwardly extending annular projection is formed at an end opening of a first shaft, and an annular protrusion near an end of a second shaft is provided. An annular groove is formed on the outer periphery, and the second shaft body is press-fitted into the first shaft body, the annular protrusion is engaged with the annular groove, and the first shaft body and the second shaft body are fitted. In the structure, when a tapered portion is formed from the annular groove of the second shaft body to the end portion, a projection for temporary fixing is formed at the end portion, and the other shaft body is inserted from above into one shaft body in a vertical posture. In addition, the tapered portion of the second shaft and the temporary fixing protrusion hold the annular protrusion of the first shaft,
The shaft and the first shaft are temporarily fixed.

[0007]

In other words, when the other shaft is inserted from above into one of the shafts in the vertical posture, the tapered portion of the second shaft and the temporary fixing projection hold the annular projection of the first shaft. Since the two-shaft body and the first-shaft body are temporarily fixed, when the upper shaft body is put on the lower shaft body in the vertical posture and press-fitted by the press-fitting machine,
The upper shaft body does not tilt or fall between mounting and press fitting.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the embodiments shown in the drawings. This embodiment shows an example in which the first shaft 1 is a cap body of a writing instrument and the second shaft 2 is a tail plug as shown in FIG. 1, but the first shaft and the second shaft are shafts. It may be a tube and a tail plug, a front shaft and a rear shaft, or the like.

As shown in FIG. 2A, an annular groove 21 is formed on the outer peripheral surface near the end of the second shaft body 2 made of a synthetic resin.
Are formed. A notch 24 is provided so as to be easily elastically deformed from the annular groove 21 to the end.
Further, a tapered portion 22 is formed on an end portion side from the annular groove 21, and a temporary fixing projection 22 which is a small
Are formed. On the other hand, the first shaft body 1 is also formed of a synthetic resin, and an inward annular projection 11 is formed at an end opening.

When the first shaft body 1 and the second shaft body 2 are press-fitted by using a press-fitting machine, the large second shaft body 1 is set in a vertical posture in a press-fitting machine (not shown). Then, the operator pushes the second shaft 2 lightly into the opening of the first shaft 1.
As a result, as shown in FIG. 2 (B), the annular projection 11 of the first shaft body 1 gets over the temporary fixing projection 22 and the annular projection 11
Are in contact with the tapered portion 22. Since the temporary fixing projections 22 are small annular projections, the annular projections 11 get over the temporary fixing projections 22 only by lightly pushing them. The annular projection 11 that has passed over the temporary fixing projection 22 is temporarily fixed by being held by the temporary fixing projection 22 and the tapered portion 22, so that the second shaft 2 can be inclined or dropped even if the operator releases his hand. There is no. Subsequently, when the press-fitting head of the press-fitting machine descends and pushes the second shaft 2, the end of the second shaft 2 is elastically deformed, and as shown in FIG.
1 and the press-fitting of the first shaft 1 and the second shaft 2 is completed.

[0011]

As described above, the fitting structure of the shaft body of the present invention is formed on the second shaft body when the other shaft body is inserted from above into one shaft body in the vertical posture. The tapered portion and the temporary fixing projection hold the inward annular projection of the first shaft body, and the second shaft body and the first shaft body are temporarily fixed. When it is put on the shaft body and press-fitted by the press-fitting machine, the upper shaft body does not tilt or fall between the placement and the press-fitting.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a press-fitting step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st shaft body 11 Inward annular protrusion 2 2nd shaft body 2 21 Annular groove 22 Tapered part 23 Temporary fixing protrusion

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) B43K 3/00 B43K 23/08-23/12 B43K 5/00-8/24 B43K 21/00-21 / twenty two

Claims (1)

(57) [Claims] 1. An inward annular projection is formed at an end opening of a first shaft body, and an annular groove is formed on an outer periphery near an end of a second shaft body. In a shaft fitting structure in which the first shaft body and the second shaft body are fitted by press-fitting into the body and engaging the annular projection with the annular groove, a taper is provided from the annular groove to the end of the second shaft body. A second shaft when the second shaft or the first shaft is inserted from above into the first shaft or the second shaft in a vertical posture. A shaft fitting structure, wherein the tapered portion of the body and the temporary fixing protrusion hold the annular projection of the first shaft, and the second shaft and the first shaft are temporarily fixed.