Dart barrel and competitive dart

Abstract

To provide a dart barrel having a shape and a mass used for competitive darts, the dart barrel having a small weight change relative to a distance from a center of gravity, and to provide a competitive dart having a small weight change relative to the distance from the center of gravity.SOLUTION: A competitive dart barrel includes a body having a shaft shape, and female screws respectively opened to a front end face and a rear end face of the body, where a tip and a shaft with a flight are attached thereto via the female screws. The dart barrel is characterized in that the body has a double structure consisting of a cylindrical core made of tungsten or a tungsten alloy, and a cylindrical outer layer made of brass and covering an outer periphery of the cylindrical core, where the cylindrical core penetrates the body from the female screw of the front end face to the female screw of the rear end face.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a dart barrel and a competitive dart having the dart barrel. [Background technology]

[0002] In darts competitions, reproducibility is of utmost importance, and players are required to be able to fine-tune the grip position and release behavior of the dart. Furthermore, the center of gravity and weight balance of the dart have a significant effect on the flight behavior of the dart, so if these characteristics differ from dart to dart, it is extremely difficult to achieve high reproducibility.

[0003] More specifically, if the front of the dart is heavier, the propulsion will be stronger, but the energy released when it makes an arc will be greater. On the other hand, if the rear of the dart is heavier, it will make a gentler arc, but the propulsion will be weaker. Also, darts are designed so that the flight acts like the tail of an airplane, so that the tip faces the dartboard. However, if a dart is released with its center of gravity unstable, its flight behavior will be unstable, and it will be impossible to accurately control where it hits the dartboard.

[0004] Furthermore, since darts are thrown in a set of three, the dart is held in the hand opposite to the throwing hand, gripped with the throwing hand, taken back, and released from that position. As a result, the released dart is affected by various motions such as rotation, rising, and falling, and in competitive darts, it is necessary to control these and accurately insert the dart into the targeted position on the dartboard. Here, if there is a large variation in mass in the axial direction of the barrel, which is the main body of the dart, the strength of the influence of each of the above motions becomes complex, making it difficult to control the dart.

[0005] In response to this, for example, Patent Document 1 (JP 2015-013053 A) discloses, for the purpose of "providing a dart barrel with a stabilized center of gravity position," "a dart barrel that is provided with connecting parts at both front and rear ends where the tip and shaft that constitute the front and rear parts of the dart are connected, forming the middle part of the dart, and that is configured by inserting a core material having a greater specific gravity than the barrel body into a core material insertion hole formed in the center of the barrel body, the core material insertion hole being formed from one front or rear end of the barrel body to a middle position, and that a threaded part is formed only on the inner peripheral surface of the end on the opening side of the core material insertion hole to form the connecting part, and that the core material is fitted into a part of the core material insertion hole deeper than the threaded part and fixed to the inner surface of the core material insertion hole with an adhesive."

[0006] The dart barrel described in Patent Document 1 above is described as having a structure in which "the core material is fixed with adhesive to the inner surface of the core material insertion hole formed from one end of the front or rear of the barrel body to the middle position, which prevents the core material from shifting forward or backward and stabilizes the center of gravity of the dart barrel."

[0007] Furthermore, Patent Document 2 (JP Patent Publication No. 2008-253537) aims to "provide a dart barrel with a new structure that allows the mass and center of gravity of the barrel itself to be adjusted as desired," and discloses "a dart barrel used in darts games, which is composed of a tip, barrel, shaft, and flight, characterized in that at least a portion of the barrel body is cylindrical, and a weight member is removably attached within the cylindrical bore."

[0008] The dart barrel described in Patent Document 2 above is said to be such that "the mass and center of gravity of the barrel weight can be easily adjusted by attaching and detaching the weight member, and the mass and center of gravity of the barrel itself can be adjusted as desired by selecting the attachment position and mass of the weight member, so there is no need to prepare many barrels, and darts can be thrown properly, increasing the accuracy of the hit." [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-013053 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-253537 Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the dart barrels described in Patent Documents 1 and 2, the stabilization and adjustment of the center of gravity position are issues, and no consideration is given at all to weight changes from the center of gravity position or weight balance.

[0011] In view of the above-mentioned problems in the prior art, the present invention aims to provide a darts barrel having the shape and mass used in competitive darts, which has a small change in weight relative to the distance from the center of gravity. Another aim of the present invention is to provide a competitive dart having the darts barrel of the present invention. [Means for solving the problem]

[0012] In order to achieve the above object, the inventors have conducted extensive research into the structure and materials of barrels used in competitive darts, and have found that it is essential for the barrel to have a double structure consisting of a cylindrical core and a cylindrical outer layer, with the cylindrical core made of tungsten or a tungsten alloy and the cylindrical outer layer made of brass, thereby arriving at the present invention.For example, even if the barrel has a double structure consisting of a cylindrical core and a cylindrical outer layer, if different materials are used, the above object cannot be achieved.

[0013] That is, the present invention provides: A dart barrel for competitive use has a shaft-shaped body and female threads that open to the front and rear end faces of the body, and a shaft having a tip and a flight is attached via the female threads. The main body has a double structure consisting of a cylindrical core portion made of tungsten or a tungsten alloy and a cylindrical outer layer portion made of brass that covers the outer periphery of the cylindrical core portion, the cylindrical core portion penetrates the main body from the female thread portion on the tip end surface to the female thread portion on the rear end surface; To provide a barrel for a dart, characterized by:

[0014] Brass barrels are relatively inexpensive and easy to process, making them suitable for mass production and used as equipment for beginners and amusement parks. However, their specific gravity is significantly lower than that of tungsten, making darts of standard shape and size too light to be easily stuck into a dartboard. Furthermore, due to factors such as weak propulsion, brass barrels are not preferred for competitive darts. On the other hand, making the brass barrel larger to ensure the weight of the dart creates problems in terms of grip and release.

[0015] In contrast, the dart barrel of the present invention has a double structure consisting of a cylindrical core made entirely of tungsten or a tungsten alloy and a cylindrical outer layer made of brass, which allows for a barrel of appropriate size, shape, and weight, as well as being relatively inexpensive. When the cylindrical core is made of a tungsten alloy, it is preferable to use one with a tungsten content of 90% or more. If the tungsten content of the tungsten alloy is low, even if the barrel's inner diameter is well-balanced, the center of gravity will be determined by the unevenness of the outer diameter. For example, in a torpedo-type dart, the center of gravity will be too far forward, causing a deviation between the center of gravity and the grip position. In contrast, using a tungsten alloy with a tungsten content of 90% or more allows for greater freedom in mass, center of gravity position, and design.

[0016] Here, tungsten alloys with a tungsten content of 90% or more are often used in existing dart barrels, but in order to make barrels of 16 to 18 g, which is the main demand, it is necessary to make bore holes in most of the barrel, which is a major problem in terms of processing technology, cost, etc. Furthermore, if bore holes are not made, the total mass and the mass 10 mm in front and behind the center of gravity become large, making it difficult to control the dart.

[0017] In the dart barrel of the present invention, a cylindrical core made of tungsten or a tungsten alloy penetrates the body from the female thread on the tip surface to the female thread on the rear surface. For example, in competitive darts, the entire barrel is generally made of tungsten, which has a high specific gravity. In the case of a tungsten barrel, a hollow region is often formed inside the barrel to reduce weight, and this hollow region causes a large change in mass of the barrel. In contrast, since the dart barrel of the present invention does not have a hollow region, the change in mass relative to the distance from the center of gravity can be minimized.

[0018] In addition, in the dart barrel of the present invention, A region of 5 mm from the center of gravity on the front end face side and the rear end face side along the axial direction of the main body is defined as a center portion, a region of 10 mm from the end face on the front end face side of the center portion to the front end face side is defined as a front portion, and a region of 10 mm from the end face on the rear end face side of the center portion to the rear end face side is defined as a rear portion, and the mass of the center portion is defined as M C , the mass of the tip is M F , the mass of the rear end is M R When the above formula is set as above, it is preferable that the following relational expressions (1) and (2) are satisfied. 0.8M C ≦M F ≦M C (1) 0.8M C ≦M R ≦M C (2)

[0019] The small mass changes at the center, tip and rear end of the barrel simplify the effects of the rotation, upward and downward movements of the dart after it is released, making it easier to understand and control the flight behavior of the dart.

[0020] M C , M F and M R The relationship is 0.85M C ≦M F ≦M C and 0.85M C ≦M R ≦M C It is preferable to satisfy 0.9M C ≦M F ≦M C and 0.9M C ≦M R ≦M C It is more preferable that the following be satisfied.

[0021] where M C , M F and M R The method for determining the value of is not particularly limited as long as it does not impair the effects of the present invention, but for example, it can be calculated from the manufacturing drawing of the dart barrel and the density of the material of the cylindrical core part and the cylindrical outer layer part. Alternatively, after actually evaluating the balance of the dart barrel and identifying the center of gravity, the center, tip and butt parts of the barrel can be cut out and the masses measured.

[0022] Furthermore, the dart barrel of the present invention preferably has a maximum outer diameter of 6.5 to 7.5 mm. By making the maximum outer diameter of the barrel 6.5 mm or more, damage can be prevented when machining the internal threads that open at the front and rear end faces of the barrel. On the other hand, by making the maximum outer diameter 7.5 mm or less, it is possible to prevent a player's own dart that has been thrown first and stuck in the dartboard from interfering with darts released thereafter.

[0023] Furthermore, the dart barrel of the present invention preferably has a total length of 35 to 50 mm. The length of the dart barrel must be such that, taking into consideration the release of the dart, the player's fingers can grip the dart without straining when gripping it with the tip and shaft attached. A barrel length of 35 mm or more allows for a relaxed grip. On the other hand, if the barrel is too long, not only will the reproducibility of the grip be impaired, but weight adjustment during manufacturing will be difficult. Furthermore, there is also the problem of interference with parts of the body during take-back. Therefore, the barrel length is preferably 50 mm or less.

[0024] Furthermore, the dart barrel of the present invention preferably has a mass of 10 to 23 g. By making the mass of the barrel 10 g or more, sufficient propulsion force can be imparted to the dart. On the other hand, by making the mass of the barrel 23 g or less, the dart does not become too heavy, and a stable release with high reproducibility can be achieved. A more preferable mass of the dart barrel of the present invention is 16 to 18 g.

[0025] Furthermore, the dart barrel of the present invention preferably has a torpedo type shape. Barrel shapes include straight and torpedo types. While the torpedo type tends to have a greater weight imbalance than the straight type, the dart barrel of the present invention can reduce the change in mass relative to the distance from the center of gravity, even if it is a torpedo type.

[0026] The present invention also provides a competitive dart comprising the dart barrel of the present invention, a tip, and a shaft having a flight.

[0027] By using the dart barrel of the present invention, the competitive dart of the present invention has a size, shape and weight suitable for competitive use, and is also relatively inexpensive, with a small change in mass relative to the distance from the center of gravity.

[0028] In addition, in the competitive dart of the present invention, the cylindrical core is detachable from the cylindrical outer layer, and even if the cylindrical outer layer has the same shape, the total mass can be adjusted by changing the tungsten content and length of the cylindrical core. Furthermore, the center of gravity can be fine-tuned by adjusting the length of the female thread, allowing for a variety of customizations to be made according to the player's preferences and conditions. [Effects of the Invention]

[0029] According to the present invention, it is possible to provide a darts barrel having a shape and mass used for competitive darts, in which the weight change with distance from the center of gravity is small. Also, according to the present invention, it is possible to provide a competitive darts having the darts barrel of the present invention. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a side view of a dart barrel according to an embodiment of the present invention. FIG. [Figure 2] 1 is a longitudinal cross-sectional view of a dart barrel according to an embodiment of the present invention. FIG. [Figure 3] FIG. 1 is a side view of a conventional dart barrel. [Figure 4] FIG. 1 is a longitudinal cross-sectional view of a conventional dart barrel. [Figure 5] 1 is a side view of a dart barrel according to the present invention. [Figure 6] 1 is a manufacturing drawing (longitudinal cross-sectional view) of a dart barrel according to the present invention. [Figure 7] This is a production drawing (side view) of a conventional dart barrel. [Figure 8] This is a manufacturing drawing (longitudinal cross section) of a conventional dart barrel. [Figure 9] 1 is a perspective view of a competitive dart that is an example of an embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0031] Representative embodiments of the dart barrel and competitive dart according to the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to these. In the following description, the same or equivalent parts will be designated by the same reference numerals, and duplicate explanations may be omitted. Furthermore, since the drawings are intended to conceptually explain the present invention, the dimensions and ratios of the components shown may differ from the actual ones.

[0032] 1. Dart barrels A side view and a longitudinal cross section of a darts barrel as an example of an embodiment of the present invention are shown in Figures 1 and 2, respectively. For comparison, a side view and a longitudinal cross section of a conventional darts barrel are shown in Figures 3 and 4, respectively. Here, the darts barrel of the present invention is a torpedo type which tends to have a large weight imbalance, while the conventional darts barrel is a straight type which has a small weight imbalance.

[0033] The dart barrel 2 of the present invention is a competition dart barrel comprising an axial body 4 and female threads 10 opening on both the front end surface 6 and the rear end surface 8 of the body 4, and a shaft having a tip and a flight is attached via the female threads 10. The body 4 has a double structure consisting of a cylindrical core 12 made of tungsten or a tungsten alloy and a brass cylindrical outer layer 14 that abuts the outer periphery of the cylindrical core 12 and covers the outer periphery of the cylindrical core 12, and is characterized in that the cylindrical core 12 penetrates the body 4 from the female threads 10 on the front end surface 6 to the female threads 10 on the rear end surface 8. In contrast, a conventional general dart barrel 20 basically consists only of the axial body 4, and the body 4 is provided with a hollow region 22 for the purpose of weight adjustment, etc.

[0034] In the dart barrel 2 of the present invention, the cylindrical outer layer 14 only needs to abut at least a portion of the outer periphery of the cylindrical core 12 and be fixed to the cylindrical core 12. The cylindrical outer layer 14 has a hollow portion of approximately the same dimensions as the cylindrical core 12, and it can be said that the cylindrical core 12 is inserted into the cylindrical outer layer 14. It is preferable that the cylindrical core 12 be detachable from the cylindrical outer layer 14. Even if the cylindrical outer layer 14 deteriorates over time due to repeated use, the cylindrical core 12 can be reused by combining it with another cylindrical outer layer 14. For example, the cylindrical core 12 can be mechanically fastened from the front and back by attaching a shaft having a tip and flights via the female thread portion 10.

[0035] Furthermore, the diameter of the cylindrical core 12 (≈ the inner diameter of the cylindrical outer layer 14) can be adjusted appropriately depending on the desired shape, size, and mass of the dart barrel 2. More specifically, for example, if it is desired to increase the overall mass of the dart barrel 2, the diameter of the cylindrical core 12 can be increased.

[0036] In the dart barrel 2 of the present invention, the maximum outer diameter of the main body 4 (cylindrical outer layer portion 14) is preferably 6.5 to 7.5 mm. By making the maximum outer diameter of the main body 4 6.5 mm or more, damage can be prevented when processing the female thread portion 10. On the other hand, by making the maximum outer diameter of the main body 4 (cylindrical outer layer portion 14) 7.5 mm or less, it is possible to prevent your own dart, which has been thrown earlier and stuck in the dartboard, from getting in the way.

[0037] Furthermore, in the dart barrel 2 of the present invention, the total length of the body 4 is preferably 35 to 50 mm. The length of the dart barrel 2 must be such that, taking into account the release of the dart, the fingers can grip the dart without straining when gripping it with the tip and shaft attached. Setting the length of the body 4 to 35 mm or more allows for a relaxed grip. On the other hand, if the body 4 is too long, not only will the reproducibility of the grip be impaired, but weight adjustment during manufacturing will be difficult. Furthermore, there is also the problem of interference with parts of the body during take-back. Therefore, it is preferable that the length of the body 4 be 50 mm or less.

[0038] Furthermore, the dart barrel 2 of the present invention preferably has an overall mass of 10 to 23 g. By making the mass of the dart barrel 2 10 g or more, sufficient propulsion can be imparted to the dart. On the other hand, by making the mass of the dart barrel 2 23 g or less, the dart does not become too heavy, and a stable release with high reproducibility can be achieved. A more preferable mass of the dart barrel 2 is 16 to 18 g.

[0039] For example, if the dart barrel 2 is a torpedo type, and the brass cylindrical outer layer 14 is φ6.5mm x 35mm with an inner diameter of φ4mm, the mass of the cylindrical outer layer 14 will be approximately 5.5g. In this case, if the cylindrical core 12 has a diameter of 4mm, a length of 23mm, and is made of a tungsten alloy with 90% tungsten, the mass of the cylindrical core 12 will be 5.1g. Therefore, the mass of the dart barrel 2 will be 5.5 + 5.1 = approximately 10.6g. Similarly, if the cylindrical outer layer 14 is φ7.5mm x 50mm with an inner diameter of φ4mm, the mass of the cylindrical outer layer 14 will be 12.8g, as described above. The mass of the cylindrical core 12 made of pure tungsten, measuring φ4 mm x 38 mm, is 9.3 g, so the mass of the dart barrel 2 is 12.8 + 9.3 = 22.1 g.

[0040] The size and shape of the female thread portion 10 are not particularly limited as long as they do not impair the effects of the present invention, but for example, the international standard M5 or the old British standard 2BA (4.7 mm x P0.81, thread angle 47.5°) can be used. Here, by making the female thread portion 10 2BA, loosening of the screw can be effectively prevented.

[0041] We will examine the mass bias (change in mass with respect to distance from the center of gravity) of the dart barrel 2 of the present invention shown in Figures 5 and 6 and the conventional dart barrel 20 shown in Figures 7 and 8, assuming the entire mass to be the same at 16 g. Figures 5 and 6 are manufacturing drawings (side view and longitudinal cross section) of the dart barrel 2 of the present invention, and Figures 7 and 8 are manufacturing drawings (side view and longitudinal cross section) of the conventional dart barrel 20. The numerical values ​​in Figures 5 to 8 are in mm. The comparison will be explained in detail below.

[0042] The dart barrel 2 of the present invention is a torpedo type with a total length of 43 mm, a maximum outer diameter of 7.5 mm, and a minimum outer diameter of 6 mm. The brass cylindrical outer layer 14 has an inner diameter of 4.01-4.02 mm, and an M5 x 0.8 internal thread 10 with a length of 8 mm is formed on each end. The cylindrical core 12, made of a tungsten alloy with a tungsten content of 90%, has a length of 35 mm and an outer diameter of 4.00 mm. The cylindrical core 12 is inserted into the cylindrical outer layer 14, and the tip and shaft are screwed to both ends of the cylindrical outer layer 14 to tighten the screws.

[0043] The density of a tungsten alloy with a tungsten content of 90% is 0.0177 g / mm 3 , the density of brass is 0.0084g / mm 3 In this case, the center of gravity of the dart barrel 2 is located 24 mm from the rear end surface 8, where the sum of the volume x density of the brass cylindrical outer layer 14 and the volume x density of the tungsten alloy cylindrical core 12 is 8 g.

[0044] Calculating from the volume and density of the material, the mass (M C ) is 4.75g, and the mass (M F ) is 4.8g, and the mass between 5mm behind the center of gravity and 10mm further behind (M R ) is 4.0g. From these values, M F and M R is 0.8M C ≦M F ≦MC and 0.8M C ≦M R ≦M C It can be seen that the following is satisfied.

[0045] In addition, M C The mass of the cylindrical core 12 is 2.22 g (125.7 mm 3 ×0.0177, and the mass of the cylindrical outer layer portion 14 is 2.53 g (301.7 mm 3 × 0.0084). M F The mass of the cylindrical core 12 is 2.22 g (125.7 mm 3 ×0.0177, and the mass of the cylindrical outer layer portion 14 is 2.58 g (307.1 mm 3 × 0.0084). M R The mass of the cylindrical core 12 is 2.22 g (125.7 mm 3 ×0.0177), and the mass of the cylindrical outer layer 14 is 1.82 g (217 mm 3 ×0.0084).

[0046] Next, we will examine a conventional dart barrel 20, a straight type with a length of 39 mm, a maximum outer diameter of 6.8 mm, and a minimum outer diameter of 6 mm. An M5 x 0.8 female screw 10, each 8 mm long, is formed on both ends, and a hollow area 22 (inner diameter 4 mm) is provided 14 mm from the front and 9 mm from the rear for mass adjustment.

[0047] The density of brass is 0.0084g / mm 3 The center of gravity is calculated in the same way as in the case of the dart barrel 2, and is found to be 18.5 mm from the rear end surface 8. Also, in the same way as in the case of the dart barrel 2, M C , M F and M R When we calculate M C is 5.7g, M F is 4.2g, M R In this case, M F and M R The value of M C It is significantly smaller than 0.8M C ≦M F ≦MC and 0.8M C ≦M R ≦M C cannot be satisfied.

[0048] In addition, M C is 321.87 mm 3 × 0.0177 = 5.7g. F The volume of the hollow region 22, the female thread portion 10, and the external groove portion is 235.9 mm 3 So, 235.9 x 0.0177 is 4.2g. R The volume of the hollow region 22, the female thread portion 10, and the external groove portion is 224.62 mm 3 So 224.62 x 0.0177 is 4.0g.

[0049] Here, for a conventional dart barrel 20, one possible method for minimizing the weight change relative to the distance from the center of gravity while satisfying the appropriate shape, size, and weight is to provide a thin through-hole (hollow region 22) in the main body 4 made of tungsten or a tungsten alloy. However, it is extremely difficult to provide a thin through-hole in the main body 4 made of tungsten or a tungsten alloy, which is a material that is difficult to process, and even if processing is achieved, the processing cost becomes unacceptably high for a dart barrel. In addition, forming a through-hole in a dart barrel 20 made of tungsten or a tungsten alloy is likely to significantly impair durability, making it unrealistic.

[0050] In contrast, the darts barrel 2 of the present invention can minimize the change in weight relative to the distance from the center of gravity while satisfying the requirements for a barrel used in competitive darts (appropriate shape, size, and weight). In addition, there is almost no need to process tungsten or tungsten alloy, which is a difficult-to-process material, and manufacturing costs can be reduced. Although many combinations of materials for the cylindrical core 12 and cylindrical outer layer 14 were considered, we were unable to find any suitable combination other than using tungsten or a tungsten alloy for the cylindrical core 12 and brass for the cylindrical outer layer 14 in order to minimize the change in weight relative to the distance from the center of gravity while satisfying the requirements for a barrel used in competitive darts (appropriate shape, size, and weight).

[0051] 2. Competitive darts A perspective view of a competitive dart, which is an example of an embodiment of the present invention, is shown in Figure 9. The greatest feature of the competitive dart 22 of the present invention is that it uses the dart barrel 2 of the present invention, and is fastened to a shaft 26 having a tip 24 at the front end and a flight at the rear end.

[0052] By using the dart barrel 2, the weight of the competition dart 22 changes little with distance from the center of gravity, and the effects of rotation, ascent and descent after the dart is released are simplified. As a result, the flight behavior of the dart becomes easier to grasp and control.

[0053] Representative embodiments of the present invention have been described above, but the present invention is not limited to these, and various design modifications are possible, all of which are included in the technical scope of the present invention. [Explanation of symbols]

[0054] 2. A dart barrel according to the present invention; 4. Main body, 6... Tip surface, 8...Rear end surface, 10... Female thread portion, 12. Cylindrical core, 14... Cylindrical outer layer, 20... Conventional dart barrels, 22. Competitive darts, 24···chips, 26···Shaft with flights.

Claims

1. A dart barrel for competitive use has a shaft-shaped body and female threads that open to the front and rear end faces of the body, and a shaft having a tip and a flight is attached via the female threads. The main body has a double structure consisting of a cylindrical core portion made of tungsten or a tungsten alloy and a cylindrical outer layer portion made of brass that covers the outer periphery of the cylindrical core portion, the cylindrical core portion penetrates the main body from the female thread portion on the tip end surface to the female thread portion on the rear end surface; A dart barrel characterized by:

2. A region 5 mm from the center of gravity on the front end face side and the rear end face side along the axial direction of the main body is defined as a center portion, a region 10 mm from the end face on the front end face side of the center portion to the front end face side is defined as a front portion, and a region 10 mm from the end face on the rear end face side of the center portion to the rear end face side is defined as a rear portion, and the mass of the center portion is M Ｃ , the mass of the tip is M Ｆ , the mass of the rear end is M Ｒ When The dart barrel according to claim 1, 0.8M Ｃ ≦M Ｆ ≦M Ｃ (1) 0.8M Ｃ ≦M Ｒ ≦M Ｃ (2)

3. The maximum outer diameter is 6.5 to 7.5 mm.

3. The dart barrel according to claim 1 or 2,

4. The total length is 35 to 50 mm.

3. The dart barrel according to claim 1 or 2,

5. The mass is 10 to 23 g.

3. The dart barrel according to claim 1 or 2,

6. having a torpedo-type shape; 3. The dart barrel according to claim 1 or 2,

7. The dart barrel according to claim 1 or 2, Chips and a shaft having a flight; Consisting of: A competitive dart featuring:

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