JPH0136638Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a capillary type writing instrument in which a core is housed inside a hard capillary made of ceramic so that it can be moved in and out, and a metal protection pipe is covered on the outside of the hard capillary.

Conventionally, as shown in Fig. 1, in the case of a hard thin tube covered with a metal protection pipe, a holding hole 2A is machined at the tip of the protection pipe 2 which is press-fitted into the tip 1, and the holding hole 2A is inserted into the holding hole 2A. The front end of the inner pipe 4 is fixed by fixing the hard thin tube 3 or by inserting another metal inner pipe 4 inside the metal protection pipe 12 press-fitted into the tip 11 as shown in FIG. It has been considered that a hard thin tube 13 made of ceramic is fixed to the protective pipe 12 in contact with the protective pipe, but in any of these cases, if the hard thin tube made of ceramic is press-fitted into the protective pipe, the hard thin tube will break, so it is fixed with adhesive. must,
This method has drawbacks such as a significant loss of productivity and the possibility of adhesive extrusion resulting in poor ink delivery.

This idea involves press-fitting a synthetic resin holder into the front part of a metal tip, then press-fitting a protective pipe into the holder, and then press-fitting a hard ceramic tube through which the protective pipe is inserted into the holder. The object of the present invention is to provide a capillary type writing instrument which eliminates all of the above-mentioned conventional drawbacks.

To explain the present invention based on the drawings, a metal protection pipe 22 made of stainless steel or the like is press-fitted into the first hole 5A of the synthetic resin holder 5 which is press-fitted into the front part of the metal tip 21. has been done. A second hole 5B having a smaller diameter than the inner diameter of the protection pipe 22 is formed at the back of the first hole 5A. A hard capillary tube 23 made of ceramic made of alumina, zirconia, silicon nitride, boron carbide, etc. passes through the protective pipe 22 and is press-fitted into the second hole 5B of the holder 5. The second hole 5
A third hole 5C having a smaller diameter than the outer diameter of the hard thin tube 23 is formed at the back of B, and the rear end of the hard thin tube 23 is locked in a stepped portion 5D located at the front end of the third hole 5C. The tip of the hard thin tube 23 is set to slightly protrude from the protection pipe 22. A large-diameter hole 5E is provided at the rear of the holder 5, and the core 6 made of synthetic resin, metal, etc. is slidably inserted into the hard thin tube 23, and the rear bent portion 6A is formed in the large-diameter hole 5E. The core 6 is inserted into the hole 5E, and the bent portion 6A is locked to the inner stage 5F of the holder 5, thereby preventing the core 6 from falling freely. A resilient porous foam 7 is inserted into the large-diameter hole 5E, and the porous foam 7 is slightly compressed by the ink distribution member 8 fixed to the tip 21 by caulking or the like, so that the inner core 6 The bent portion 6A is projected forward.
The tip of the core 6 slightly protrudes from the hard thin tube 23, and when pressure is applied to the core 6, it retracts to the tip of the hard thin tube 23 against the elasticity of the porous foam 7. The large diameter part 21A of this tip 21 is press-fitted into the shaft 9 which has an air hole 9A on the front side surface, and the rear part of the ink distribution member 8 is buried in the front end of the ink storage body 10 built in the shaft 9, and a thin tube is formed. A type writing instrument is constructed.

Next, to explain the method of assembling the device shown in FIG. tubule 2
Press in 3. After this holder 5 is press-fitted into the front part of the tip 21, the core 6 whose rear part is bent is inserted into the third hole 5C of the holder 5. Furthermore, the bent portion 6 of the center core 6
The porous foam 7 is positioned in contact with the ink distribution member 8 from behind on the large diameter portion 21A of the tip 21.
is inserted and the rear end of the tip 21 is caulked inward to fix the ink distribution member 8. At this time, the porous foam 7 is held between the bent portion 6 of the core 6 and the front end of the ink distribution member 8 with an appropriate force, and the tip of the core 6 is appropriately projected from the tip of the hard thin tube 23. Further, the shaft 9 is press-fitted into the tip 21, and the rear part of the ink distribution member 8 is buried in the front end of the ink storage body 10 built into the shaft 9, thereby assembling the capillary type writing instrument shown in FIG.

This device constructed as described above is capable of handling even if a shock is applied to the tip of the capillary type writing instrument due to a drop, etc.
The outer diameter of the ceramic hard tube, which is easy to break, is protected by a metal protection pipe, and the metal protection pipe and ceramic hard tube are fixed to a synthetic resin holder, so they are protected. Since the pipe and hard tube can absorb the impact force between them and the holder, the hard tube will not be damaged.Furthermore, in order to press fit and fix the ceramic hard tube into the synthetic resin holder, press-fitting is required. It can be produced at low cost without causing the hard thin tube to break at times, and has a revolutionary effect in practical use compared to conventional thin tube type writing instruments.

[Brief explanation of the drawing]

FIGS. 1 and 2 are longitudinal cross-sectional views of the main parts of a conventional thin tube writing instrument, respectively, and FIG. 3 is a longitudinal cross-sectional view of the main parts of the thin tube writing instrument of this invention. 21... Tip metal, 22... Protective pipe, 23... Hard tube, 5... Holder, 6... Core, 7... Porous foam,
8... Ink distribution member, 9... Shaft, 10... Ink storage body.

Claims (1)

[Scope of utility model registration request] In a thin tube type writing instrument in which a core 6 is inserted and removable inside a hard thin tube 23, a metal protection pipe 22 is press-fitted into a synthetic resin holder 5, and a ceramic pen inserted into the inside of the protection pipe 22 is used. This thin tube type writing instrument is characterized in that a hard thin tube 23 made of aluminum is press-fitted into the holder 5, and the tip of the hard tube 23 slightly protrudes from the tip of the protective pipe 22.