JPS6139579Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a gas pressurized ballpoint pen, and particularly to a gas pressurized ballpoint pen with an improved sealing structure of the tail plug at the rear end.

Conventionally, when assembling an ink cylinder for a gas pressurized ballpoint pen, sealing the tail plug at the rear end is extremely troublesome. For example, as shown in FIG. 3, a substantially cylindrical tail plug 8 is tightly fitted into the rear end of the ink cylinder 1 and sealed with a sealing material 7 interposed therebetween. Since pressurized gas is sealed inside the ink cylinder 1, leakage must be reliably prevented, and if the seal is incomplete, the pressurizing function to the ink will not be achieved. In addition, the rigid tail plug 8 is press-fitted, and the sealing material 7 attached to the tip of the tail plug 8 is impregnated into the fitting part of the tail plug 8 by the centrifugal force of the centrifuge to seal it. This resulted in an increase in man-hours.

In order to solve this problem, it has been proposed to interpose an O-ring between the tail plug and the inner peripheral surface of the ink cylinder. For example, Utility Model Publication No. 49-17317, Publication Utility Model Publication No. 54-34668
It has a sealed structure according to the publication. In these cases, an O-ring is fitted into a groove formed on the peripheral surface of the tail plug, and the tail plug is forcibly inserted into the rear end of the ink cylinder. However, in order to maintain sealing, the O-ring needs to protrude slightly from the outer diameter of the tail plug, so when the tail plug is inserted into the ink cylinder, the O-ring does not touch the rear opening edge of the ink cylinder. This caused a so-called turning-up phenomenon, making it extremely troublesome to insert the O-ring into the ink cylinder.

Therefore, this invention was devised to eliminate the existing drawbacks as described above, and although the O-ring was used to achieve sealing performance, it made it extremely easy to insert the O-ring, and The purpose of the present invention is to provide a gas pressurized ballpoint pen that can reliably prevent leakage of pressurized gas.

Therefore, this idea was developed for a gas pressurized ballpoint pen, which includes an O-ring that fits into the inner peripheral surface of the ink cylinder, and a substantially cylindrical tail that has a diameter slightly larger than the inside diameter of the ink cylinder and has a tapered tip. A locking ring is provided around the inner peripheral surface of the ink cylinder, and the ink cylinder is loaded from the rear end so that the O-ring is in contact with this locking ring. The tail plug is press-fitted into the end opening, and the O-ring is brought into close contact with the inner circumferential surface of the ink cylinder at the circumferential surface of the tapered part of the tail plug. An example of the invention will be described.

Reference numeral 1 shown in the figure is an ink cylinder made of metal or synthetic resin that can also serve as an axial cylinder. The ink cylinder 1 is formed into a cylindrical or polygonal cylinder shape with an internal shape having a circular cross section, and a tip (not shown) that holds a ball is fitted and fixed at the tip.
Ink 2 is filled inside.

A locking ring 3A that protrudes in the axial direction is provided around the inner peripheral surface of the rear end opening of the ink cylinder 1. The locking ring 3A may be one in which the inner peripheral surface itself projects, or a ring-shaped ring may be press-fitted into the ink cylinder 1 and then fixed therein.

Then, the O-ring 4, which is fitted onto the inner peripheral surface of the ink cylinder 1, is loaded from the rear end of the ink cylinder 1 so as to be in contact with the rear end surface of the locking ring 3A.

On the other hand, a tail plug 5 that is forcibly fitted into the rear end of the ink cylinder 1
is made of metal, synthetic resin, rubber-like elastic material, etc. The tail plug 5 is formed with a diameter smaller than the inner diameter of the O-ring 4, and has a tapered part 5A having an inclined surface so that the diameter gradually becomes larger toward the rear end, and a main body formed with a diameter slightly larger than the inner diameter of the ink cylinder 1. It consists of part 5B.

As mentioned above, the O-ring 4 is loaded in advance so as to be in contact with the locking ring 3A inside the ink cylinder 1, and then the O-ring 4 is attached to the rear end opening of the ink cylinder 1 in the pressurized gas chamber. Press fit the stopper 5. This press fit is
The O-ring 4 is connected to the inner peripheral surface of the ink cylinder 1 and the locking ring 3A.
This is done until the rear end surface and the outer peripheral surface of the tapered part 5A of the tail plug 5 are deformed so as to come into close contact with each other, thereby completing the assembly.

This invention is constructed as described above, and the locking ring 3A is provided around the inner peripheral surface of the ink cylinder 1, and the ink cylinder 1 is loaded from the rear end so that the O-ring 4 is brought into contact with the locking ring 3A. Then, the tail plug 5 is press-fitted into the rear end opening of the ink cylinder 1 in the pressurized gas chamber, and the O-ring 4 is inserted into the ink cylinder 1 at the circumferential surface of the tapered part 5A of the tail plug 5.
Because it is in close contact with the inner circumferential surface, pressurized gas flows into the ink cylinder 1.
and is sealed and held by an O-ring 4. Further, since the tail plug 5 has a diameter slightly larger than the inner diameter of the ink cylinder 1 and is press-fitted into the ink cylinder 1, the tail plug 5 does not come out due to the pressure of the pressurized gas.

Furthermore, the O-ring 4 is loaded in advance in a state in which it is in contact with a locking ring 3A provided around the inside of the ink cylinder 1, and the taper of the tail plug 5 which is press-fitted from the rear end opening of the ink cylinder 1 is fixed. Since it is pressed at part 5A,
The O-ring 4 itself deforms without shifting at the loading position, ensuring sealing performance. Therefore, compared to conventional methods in which a tail plug with an O-ring fitted in advance is fitted into the ink cylinder, the O-ring 4 does not turn over and can be loaded reliably, which is extremely useful in practical terms. It has a great effect.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of this invention. Figure 1 is a cross-sectional view of the main part during assembly, Figure 2 is a cross-sectional view of the main part during use, and Figure 3 is a conventional gas FIG. 2 is a sectional view of a main part showing a tail plug structure of a pressurized ballpoint pen. 1... Ink cylinder, 2... Ink, 3A... Locking ring, 4... O ring, 5... Tail plug, 5A...
Tapered part, 5B...Body part, 7...Sealing material,
8...Tail plug.

Claims (1)

[Scope of utility model registration request] A gas pressurized ballpoint pen is equipped with an O-ring that fits into the inner peripheral surface of the ink cylinder, and a generally cylindrical tail plug with a diameter slightly larger than the inner diameter of the ink cylinder and a tapered tip. A locking ring is provided around the inner circumferential surface, and the ink cylinder is loaded from the rear end so that the O-ring comes into contact with this locking ring, and the tail plug is press-fitted into the opening at the rear end of the ink cylinder in the pressurized gas chamber. A gas pressurized ballpoint pen characterized in that the O-ring is brought into close contact with the inner circumferential surface of the ink cylinder at the circumferential surface of the tapered part of the tail plug.