JPH0674378U - Ink backflow prevention mechanism for writing instruments - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an ink backflow prevention mechanism for a writing instrument which is improved so that it can be easily and inexpensively manufactured without requiring any precise processing steps that are troublesome and cause a rise in production cost. [Structure] A valve seat 4 is provided on a front end side inner peripheral surface on which the tip 3 of the ink containing tube 1 is mounted, and a ball valve 5 is provided on the front end side inner peripheral surface with a proper distance from the valve seat 4. Is provided with a restricting portion 6 for restricting the amount of free movement of the ball valve 5, and a valve chamber 7 is formed between the restricting portion 6 and the valve seat 4. Configure. As a result, the ink backflow prevention mechanism can be easily incorporated in the tip end side of the ink containing tube 1 without performing any complicated processing that is troublesome and causes a rise in production cost. It is designed to be able to reduce.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an ink backflow prevention mechanism of a writing instrument, and more specifically, a backflow of internal ink that occurs when the writing posture is continued for a long time, such as when the writing instrument is used with the rear end side facing downward. , The improvement of the ink backflow prevention mechanism that prevents the outflow to the outside due to the backflow.

[0002]

[Prior art and its problems]

 Generally, a writing instrument such as a ball-point pen is designed so that the internal ink in the ink containing tube is sent to the tip of the tip by atmospheric pressure and the ink is supplied to the transfer ball at the tip of the tip. Therefore, since an outside air introduction hole for introducing outside air into the ink containing tube is provided at an appropriate location such as the rear end of the ink containing tube, the writing instrument should be in an upward position with the rear end side facing downward. When the writing tool is used for a long time and the writing posture is taken, air enters the chip from the gap of the transfer ball ink at the tip of the chip, and the air that enters the chip causes the ink in the ink storage tube to move to the rear end side. There is a risk that the air will flow back to the outside and will flow out from the rear end outside air introduction hole. Therefore, conventionally, various ink backflow prevention mechanisms for preventing backflow of ink have been developed and proposed. For example, a ballpoint pen provided with an ink backflow prevention mechanism proposed by the applicant of the present application is known (see Japanese Utility Model Publication No. 54-15703). As shown in FIG. 4, this conventional backflow prevention mechanism has a valve seat 23 fitted with an ink flow hole 22 inside the tip side of an ink containing tube 21 into which the tip 20 is fitted. The ball valve 25 is freely inserted in the valve chamber 24 formed between the valve seat 23 and the rear end surface of the tip 20, and when the writing instrument is turned upward, the ball valve 25 is placed on the valve seat 23 by its own weight. The ink flow hole 22 is closed by riding on the ink, and the backflow of ink is prevented. However, in this conventional ink backflow prevention mechanism, since it is configured to be built-in on the tip side of the ink containing tube 21, the backflow of the ink is prevented, and at the same time the ink in the ink containing tube 21 is not covered by the tip when writing. Even if the ball valve 25 rides on the rear end surface of the chip 21, which is thinner than the ink containing tube 21 and requires a precise processing process so as to flow into the 20 ink channels 26, the ink groove that communicates with the ink channel 26 Since 27 must be formed in a radial shape, a special dedicated processing machine is required for its production, and there is a problem that production cost rises due to enormous capital investment.

[0003]

[Problems to be solved by the device]

 The present invention has been made in view of such a conventional situation, and provides an ink backflow prevention mechanism for a writing instrument improved so that it can be easily and cheaply manufactured without any need for a precise processing step that causes a troublesome and high production cost. With the goal.

[0004]

[Means for achieving the object]

 The technical means taken by the present invention to achieve the above object is to provide a valve seat on the inner peripheral surface of the front end side of the ink containing tube to which the tip end of the ink containing tube is attached, and to provide a proper distance from the valve seat. A regulation part for regulating the amount of ball valve movement is provided on the inner peripheral surface of the front end side, and a valve chamber is formed between this regulation part and the valve seat, and the ball valve is movably inserted into this valve chamber. It is characterized by being built internally.

[0005]

[Work]

 Thus, according to the above-described technical means of the present invention, it is possible to manufacture a writing instrument in which the ink backflow prevention mechanism is built in and provided on the tip side of the ink containing tube. Then, when the writing instrument is turned upward, the ball valve in the valve chamber rides on the valve seat by its own weight, and the ink is filled with the tip end side of the ink containing tube to which the tip end of the valve seat is attached. The inflow of air from the rear end side is completely blocked, and the back flow of the ink in the ink containing tube to the rear end side is prevented. On the other hand, when the writing instrument is in the writing state, the ball valve separates from the valve seat by its own weight, and the front side and the rear side of the ink storage tube are communicated with each other, and the outside air is introduced, so that the ink in the ink storage tube is large. Ink is supplied to the tip side of the tip under atmospheric pressure, and the ball valve separated from the valve seat is internally retained in the valve chamber while being received by the regulating portion.

[0006]

[Example] An example of the embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a case where the writing instrument is a ball-point pen. As the ink storage tube, the pen body 1 is formed into a cylindrical shape that can be filled with the ink 2, and the tip opening portion is formed into a structure (shape) into which the tip tip 3 can be fitted and mounted, and the tip tip 3 is attached to the tip. Is directly attached and configured. A valve seat 4 is provided on the inner peripheral surface of the front end side of the pen body 1 to which the tip 3 is attached, and the ball valve 5 is free to move on the inner peripheral surface of the front end side at an appropriate distance from the valve seat 4. A regulating portion 6 for regulating the amount is provided, a valve chamber 7 is formed between the regulating portion 6 and the valve seat 4, and a ball valve 5 is loosely inserted inside the valve chamber 7. When the ballpoint pen is directed upward, the ball valve 5 rides on the valve seat 4 by its own weight, so that the ink is filled with the tip side of the pen body 1 on which the tip 3 is mounted with the valve seat 4 as a boundary. The flow of the outside air, i.e., the flow of the ink 2, to the rear end side of the pen body 1 is completely blocked, and the back flow of the ink 2 in the pen body 1 to the rear end side is prevented.

The valve seat 4 and the restricting portion 6 are integrally formed in the main body 1 at the time of injection molding of the pen main body 1 made of a hard synthetic resin material such as vinyl chloride, so that the inner circumference of the main body 1 on the front end side is formed. The valve seat 4 is provided on the inner surface of the cylindrical pen body 1 so as to project in a ring shape from the inner diameter of the pen body 1. It has an ink introduction port 8 from the rear end side to the front end side which has a smaller diameter. In the case of a normal writing posture with the ballpoint pen facing downward, that is, the tip 3 facing downward, the ink inlet 8 is mounted with the rear end side of the pen body 1 filled with the ink 2 and the tip chip 3. The ink 2 is guided to the tip 3 through the valve chamber 7 by communicating with the tip side, and when the ballpoint pen is turned upward, the ink is blocked by the ball valve 5 that rides on the valve seat 4 by its own weight. The ink 2 introduced to the front end side of the pen body 1 does not return to the rear end side. That is, the backflow of the ink 2 in the pen body 1 is prevented.

On the other hand, the restricting portion 6 has an appropriate interval in the circumferential direction on the inner peripheral surface further on the tip side of the pen body 1 with an appropriate interval at which the ball valve 5 can move (move) from the valve seat 4. It is formed by projecting ball receiving convex portions 6a at a few places (three in the drawing) so that the ball valve 5 is received by each convex portion 6a. Secures and forms an ink introducing groove 9 for introducing the ink once introduced into the valve chamber 7 from the ink introducing port 8 of the valve seat 4 to the tip 3 side (see FIG. 2).

Thus, according to the above-described embodiment, the pen body 1 is injection-molded with a hard synthetic resin material, so that the valve seat 4 having the ink introduction port 8 and the ball are provided at the tip side of the body 1. The ball receiving convex portion 6a that regulates the amount of free movement of the valve 5 and the valve chamber 7 that allows the ball valve 5 to freely move therein are integrally provided. By inserting the ball valve 5 into the valve chamber 7, the ink It is possible to manufacture a ball-point pen having a backflow prevention mechanism built-in on the front end side of the pen body 1. Therefore, since the ink backflow prevention mechanism excluding the ball valve 5 can be built in the inner peripheral surface of the pen body 1 at the same time when the pen body 1 is molded, the ink can be manufactured easily and inexpensively. A ballpoint pen having a backflow prevention mechanism can be provided at low cost. When the ballpoint pen 5 in the valve chamber 7 is placed in an upward state as shown in FIG. 3, the ball valve 5 rides on the valve seat 4 by its own weight and closes the ink inlet 8 of the valve seat 4 to close the ink in the pen body 1. 2 Prevent backflow to the rear end side. On the other hand, when the ballpoint pen is in a writing state as shown in FIG. 1, the ball valve 5 separates from the valve seat 4 by its own weight to open the ink inlet port 8, and the ink 2 passes under the atmospheric pressure through the valve chamber 7 and the tip end. It is in a state of being introduced to the chip 3 side and is supplied to the chip 3. The ball valve 5 separated from the valve seat 4 is internally retained in the valve chamber 7 while being received by the ball receiving convex portion 6a without rolling down to the tip 3 side.

In the above-described embodiment, the case where the pen body 1 directly filled with the ink 2 is used as the ink containing tube has been described in detail. As described above, the valve seat 4 having the ink introduction port 8 and the regulating portion 6 are provided on the inner peripheral surface of the tip side on which the tip of the tip (also referred to as a refill) is mounted, and the ball is provided in the valve chamber 7 formed therebetween. It is of course also possible to make the ball-point pen in which the valve 5 is movably provided and the ink backflow prevention mechanism is provided at the tip side thereof and the core is inserted and loaded in the pen body. In this case, as is well known, the pen body is formed into a cylindrical shape into which a core can be loaded.

Further, in the present embodiment, the ink backflow prevention mechanism is also provided in the tail plug 11 in which the outside air intake hole 10 to be fitted and attached to the rear end opening of the pen body 1 is provided. The ink backflow prevention mechanism is built-in at the front end side even if a low-viscosity ink is used as the ink 2 to be filled in the pen body 1 or a ball-point pen is dropped and a considerably large impact is applied. With the synergistic effect with the above, the configuration is designed so that the backflow of ink can be prevented more completely.

In the figure, reference numeral 12 denotes a high-viscosity liquid such as grease that is injected and incorporated in the rear end side of the pen body 1. By injecting and injecting the high-viscosity liquid 12, ink 12 is applied to the rear end side. It can be prevented from falling and the effect can be enhanced.

[0013]

[Effect of device]

 Since the ink backflow prevention mechanism of the writing instrument of the present invention is constructed as described above, it has the following operational effects. Since the back end of the ink is prevented from flowing back inside the tip side by constructing the inside of the ink holding tube in which the tip is mounted so that it can be built-in inside the tip side, the ink is stored like a conventional writing instrument. There is no need to devise an inflow means such as an ink groove or the like for allowing the ink in the tube to flow into the ink flow path of the tip chip. Therefore, it can be easily manufactured without any new processing on the rear end of the chip, which requires complicated and precise processing as in the past, which greatly improves productivity and at the same time reduces production costs. Therefore, it is possible to provide a writing instrument equipped with an ink backflow prevention mechanism at low cost by improving productivity and reducing costs.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an example of implementation of an ink backflow prevention mechanism of a writing instrument of the present invention, showing a writing state.

FIG. 2 is an enlarged sectional view taken along the line III-III in FIG.

FIG. 3 is a vertical cross-sectional view showing the state of being directed upward.

FIG. 4 is a vertical sectional view showing a conventional example.

[Explanation of symbols]

 1 ... Pen body (ink storage tube) 2 ... Ink 3 ... Tip 4 ... Valve seat 5 ... Ball valve 6 ... Regulator 7 ... Valve chamber

Claims (3)

[Scope of utility model registration request] 1. A valve seat is provided on a front end side inner peripheral surface on which a tip of an ink containing tube is mounted, and a ball valve floating amount is provided on the front end side inner peripheral surface with an appropriate distance from the valve seat. Of a writing instrument characterized in that a valve section is provided between the restriction section and the valve seat, and a ball valve is loosely inserted inside the valve chamber. Ink backflow prevention mechanism. 2. The ink backflow prevention mechanism for a writing instrument according to claim 1, wherein the ink containing tube is a writing instrument body. 3. The ink backflow prevention mechanism for a writing instrument according to claim 1, wherein the ink storage tube is a core that is inserted and loaded in the writing instrument body.