JPH0213193Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial Application Field" The present invention relates to a tail plug mounting structure for sealing the opening of a cylinder, and is used for sealing the tail of an ink tank of a ballpoint pen, for example. It can also be applied to the ink tank of a pressure-type ballpoint pen.

"Conventional technology" As for the conventional tail plug mounting structure, for example,
There is one such as that disclosed in Publication No. 49-17317.

That is, this publication discloses that a tail plug is inserted into the end of a cylindrical body and adhered thereto, and an O-ring is interposed between the tail plug and the cylindrical body.

As another example, a ring-shaped protrusion is provided on the outer periphery of the tail plug, the tail plug is press-fitted into the end of the cylinder, and the ring-shaped projection is pressed against the inner hole of the cylinder to form a seal. ing.

``Problem that the invention aims to solve'' However, with such conventional tail plug mounting structure, in the former case, the O-ring easily comes off when the O-ring is inserted into the tail plug and is pushed into the cylinder body. , adhesive work is required and workability is poor, and the durability of the O-ring may become a problem.In the latter case, accuracy control of parts for press-fitting is expensive, and if the accuracy is poor, If the fit is poor, the sealing performance may be poor, or if the fit is too strong, the cylinder body may become distorted.Furthermore, the head of the tail plug may be damaged because the tail plug must be pushed too hard. There was a problem that there was.

The present invention has been made by focusing on these conventional problems, and aims to provide a tail plug mounting structure that facilitates accuracy control and can reliably seal the opening of the cylinder body. It is an object.

``Means for Solving the Problems'' The gist of the present invention to achieve such an objective is to provide a mounting structure for a tail plug for sealing the opening of a cylinder body, which is attached via a bush made of elastic material. The bushing has a structure in which a tail plug is fitted into an internal hole of the cylindrical body, and the bushing is provided with ring-shaped protrusions protruding from a plurality of locations in the axial direction that press against the internal hole of the cylindrical body, and the tail plug is fitted into the internal hole of the bushing. The bushing has a plug body that is inserted into the inner hole of the bushing, and a ring-shaped projection that is press-fitted into the inner surface of the inner hole of the bushing is provided on the outer periphery of the plug body, and when the tail plug is attached, The tail plug mounting structure is characterized in that the ring-shaped protrusion of the plug body is positioned between adjacent ring-shaped protrusions of the bush in the axial direction.

"Operation" When the bushing and tail plug are press-fitted into the opening of the cylinder, the ring-shaped protrusion of the bush comes into pressure contact with the inner surface of the internal hole of the cylinder, and the ring-shaped projection of the tail plug comes into pressure contact with the inner hole of the bush. The position where the ring-shaped protrusion of the tail plug presses against the inner surface of the inner hole of the bushing is between the ring-shaped protrusions of the bushing, and if you press it considerably, the bushing will bend and the ring-shaped protrusion will press against the cylinder body with an appropriate pressure. It is pressed against the inner surface of the internal hole to seal it.

“Embodiment” An embodiment of the present invention will be described below based on the drawings.

1 to 4 show an embodiment of the present invention. This embodiment is an example of application to an ink tank of a ballpoint pen.

The ink tank 10 of the ballpoint pen has a writing tip 11 at the tip and is sealed.The main body has a cylindrical tank body 12, and the opening 14 of the internal hole 13 of the tank body 12 is located at the top 15 of the tank body 12. It is open to

The opening 14 is hermetically sealed by a tail plug 30 that fits into the tank body 12 via a bush 20.

The bushing 20 has a cylindrical shape made of an elastic material, has an inner hole 21, and has two ring-shaped protrusions 23, 23 projecting from the outer periphery of the peripheral wall 22 and spaced apart in the axial direction. Outer diameter D1 of ring-shaped protrusions 23, 23
is the inner diameter D of the top of the internal hole 13 of the ink tank 10
2, and is set to a tight fit.

The tail plug 30 has a head 31 having an outer diameter equal to the outer diameter of the top 15 of the tank body 12 of the ink tank 10.
A large diameter portion 33 is formed at the base of the plug body 32 to fit into one end of the inner hole 21 of the bushing 20.
A ring-shaped protrusion 34 that is press-fitted into the ring 1 is provided in a protruding manner. An inclined guide surface 35 is formed on the front surface of the ring-shaped projection 34 .

The ring-shaped protrusion 34 of the tail plug 30 is aligned with the ring-shaped protrusion 2 of the bushing 20 arranged in the axial direction in the installed state.
It is set to be located between 3 and 23.

To attach the tail plug 30 in the above configuration,
The bushing 20 is assembled with the tail plug 30 in advance. That is, the plug body 32 of the tail plug 30 is inserted into the bush 2.
0 into the inner hole 21.

Since the outer diameter of the bushing 20 is not limited, when the ring-shaped protrusion 34 provided at the tip of the plug body 32 of the tail plug 30 is inserted into the inner hole 21 of the bushing 20, the diameter of the bushing 20 expands somewhat, and the ring-shaped projection 34 is inserted into the inner hole 21 of the bushing 20. The projection 34 is guided by the guide surface 35 and can enter relatively easily.

When the plug body 32 of the tail plug 30 is completely inserted into the inner hole 21 of the bushing 20, the ring-shaped protrusion 34 is inserted into the bushing 2.
The large diameter portion 33 is press-fitted into one end of the inner hole 21 .

This bushing 20 is attached to the tail plug 30,
It is press-fitted into the internal hole 13 from the opening 14 of the ink tank 10 .

As the bushing 20 is press-fitted, the ring-shaped projection 23 on the tip side of the bushing 20 first interferes with the edge of the opening 14. However, since there is nothing on the inner diameter of the ring-shaped protrusion 23 that presses it from the inside, the ring-shaped protrusion 23 is easily deformed and easily enters the inner periphery of the inner hole 21 while coming into elastic contact with the inner circumference.

When the next ring-shaped protrusion 23 interferes with the edge of the opening 14, it is similarly deformed and enters into elastic contact with the inner periphery of the inner hole 21. When both ring-shaped protrusions 23, 23 come into elastic contact with the inner periphery of the internal hole 13 of the ink tank 10, the entire bushing 20 becomes in a state where the diameter is slightly reduced.

Since the ring-shaped protrusion 34 of the plug body 32 of the tail plug 30 is in pressure contact with the inner surface of the peripheral wall 22 located between the ring-shaped protrusions 23, 23 of the bushing 20, it is shown in FIG. 4, although it is slightly exaggerated. As the bushing 20 deforms elastically, the ring-shaped protrusion 34 of the tail plug 30 sinks into the inner surface of the inner hole 21 of the bushing 20, and the large diameter portion 3
3 is also press-fitted into the inner hole 21 of the bushing 20 at its base in the radially expanding direction.

When the tail plug 30 is completely inserted, the edge of the head 31 comes into contact with the edge of the opening 14 of the ink tank 10 and stops, as shown in FIG. Internal hole 1 of tank 10
3, the large diameter portion 33 and ring-shaped protrusion 34 of the tail plug 30 are press-fitted into the inner hole 21 of the bushing 20, and the opening 14 of the ink tank 10 is completely sealed.

The force for fitting the ink tank 10, bushing 20, and tail plug 30 together is generated by the elasticity of the bushing 20.
Excessive press-fitting force will not occur.

In the above embodiment, the ring-shaped projections 23 are provided at two locations on the bushing 20, and the ring-shaped projection 34 is provided at one location on the tail plug 30. They may be arranged alternately and added as appropriate.

"Effects of the Invention" According to the tail plug mounting structure of the present invention, the tail plug is press-fitted to the end of the shaft cylinder through the bushing made of elastic material, and the bushing is pressed against each other by utilizing its elastic deformation. Because of this, even if the accuracy of the fitting relationship is made coarse, the pressure contact force will not become excessive or insufficient, and the opening can be reliably sealed. Since the pushing force is small, the tail plug will not be damaged and workability is good.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention. Figure 1 is a sectional view of the main part showing the tail plug fully attached, and Figure 2 is a front view showing the top of the ink tank in cross section. FIG. 3 is a vertical sectional view of the bushing, and FIG. 4 is an enlarged sectional view of the main part showing details of the press-fitted state of the tail plug. 10... Ink tank, 12... Tank body, 1
3... Internal hole, 14... Opening, 20... Bush,
21... Inner hole, 22... Peripheral wall, 23... Ring-shaped projection, 30... Tail plug, 32... Plug body, 34... Ring-shaped projection.

Claims (1)

[Scope of utility model registration request] This is a mounting structure for a tail plug for sealing an opening of a cylinder, in which the tail plug is fitted into an internal hole of the cylinder through a bushing made of an elastic material, and the bush has a structure in which the inside of the cylinder is fitted. Ring-shaped protrusions that press against the holes are protruded at multiple locations in the axial direction, and the tail plug has a plug body that is inserted into the inner hole of the bushing, and the outer periphery of the plug body has a ring-like projection that is inserted into the inner hole of the bushing. A ring-shaped protrusion that press-fits into the inner surface is protruded, and the ring-shaped protrusion of the plug body is positioned between adjacent ring-shaped protrusions of the bushing in the axial direction when the tail plug is attached. The tail plug mounting structure is characterized by: