JP2021036815A - Telescopic rod - Google Patents

Abstract

To provide an inexpensive telescopic rod preventing fixation, rotation and the like of each rod joint with a simple structure.SOLUTION: A telescopic rod comprises a plurality of rod joints. A diameter-reduced part 27 and a fitting recessed part 26 are formed inside a tip end part 20 of a fifth rod joint 15 toward a rear end side 25 from a tip end side 24. The inner surface 29 of the fitting recessed part 26 is inclined at a taper ratio T1. The diameter-reduced part 27 reduces the diameter of the tip end opening of the fifth rod joint 15. A first fitting protruding part 36 and a second fitting protruding part 37 are formed on the rear end part 21 of a fourth rod joint 14 toward the tip end side 24 from the rear end side 25. The diameter of the first fitting protruding part 36 is gradually reduced toward the tip end side 24 at a taper ratio T2. The diameter of the second fitting protruding part 37 is gradually reduced toward the tip end side 24 at a taper ratio of T3. Each of the taper ratios satisfies T3≤T1<T2.SELECTED DRAWING: Figure 2

Description

The present invention relates to the structure of a so-called swing-type fishing rod.

A so-called swing-type fishing rod or ball handle (hereinafter referred to as a "swing rod") consists of a plurality of sections, and each section is assembled to form a telescopic structure. Each node is generally made of a resin reinforced with carbon fiber, and is called the first node and the second node in order from the one having the smallest outer diameter among the plurality of nodes, and the node having the largest outer diameter is the original node. Is called. The original section is a part that the fisherman grips when operating the swing rod, and the section arranged inside this original section is called the original upper section. In actual fishing, the swing rod is required to expand and contract quickly and smoothly.

Since each node constitutes a telescopic as described above, for example, in the case of a ball handle, when the fisherman vigorously shakes the original node to extend each node, the adjacent nodes are pulled relatively strongly in the axial direction. , May fit tightly and stick to each other. On the other hand, in the swing rod, when the fitting between adjacent nodes is weak, the adjacent nodes rotate relatively in the axial direction, or when the angler does not intend in actual fishing, the swing rod is shortened (each). Knots may fall off). In order to eliminate such inconvenience, various measures have been taken conventionally (see, for example, Patent Document 1 and Patent Document 2).

The structure of the ball handle disclosed in Patent Document 1 is a ball or metal member at the rear end of the original upper section and the tip of the original section, respectively, in order to realize a smooth slide of the original upper section with respect to the original section. Is arranged, and in order to prevent the original node from sticking to the original upper node, a groove is provided inside the tip of the original node to reduce the contact area with the original upper node.

In the structure of the ball handle disclosed in Patent Document 2, in order to prevent the original upper node and the original node from sticking to each other, the inside of the tip of the original node is reduced in diameter to form a step portion, and this step is formed. The diameter of the rear end of the original upper section is expanded so as to abut the portion. Further, in order to prevent the relative rotation of the original upper node with respect to the original node, a locking groove is formed at the rear end of the original upper node, and the locking projection that engages with this locking groove is the tip of the original node. It is provided inside.

Japanese Patent No. 3860757 Japanese Unexamined Patent Publication No. 2003-174835

However, the formation of the groove for preventing sticking and the formation of the locking groove and the locking projection for preventing rotation are not easy in forming the knot, and there is a problem that the manufacturing cost of the knot is significantly increased.

Therefore, an object of the present invention is to provide an inexpensive swing rod capable of preventing sticking and rotation of each node in actual fishing by a simple structure.

(1) The swing rod according to the present invention has a large-diameter knot and a small-diameter knot arranged adjacent to the inside of the large-diameter knot, and the small-diameter knot is an axis with respect to the large-diameter knot. It is a swing rod that slides relatively in the direction. The large-diameter knot has a fitting recess formed inside the tip thereof with a predetermined taper ratio T1 toward the rear in the axial direction to gradually increase the inner diameter, and is provided axially forward from the fitting recess. It has a reduced diameter portion that reduces the inner diameter of the tip. At the rear end of the small-diameter node, a first fitting convex portion that gradually reduces the outer diameter at a predetermined taper ratio T2 toward the front in the axial direction is formed, and from the first fitting convex portion. It has a second fitting convex portion provided in the front in the axial direction and gradually reducing the outer diameter toward the front in the axial direction at a predetermined taper ratio T3 different from the taper ratio T2.

According to this configuration, the swing rod is extended by sliding the small diameter node with respect to the large diameter node. At this time, the rear end of the small diameter node is fitted inside the tip of the large diameter node. Specifically, the second fitting convex portion and the first fitting convex portion of the small diameter node are pushed into the fitting concave portion of the large diameter node. Since the taper ratio T3 of the second fitting convex portion and the taper ratio T1 of the first fitting convex portion are different, the large-diameter knot and the small-diameter knot are the second fitting convex portion or the first fitting convex portion. It fits tightly on one side and weakly on the other side. That is, the large-diameter knot and the small-diameter knot are fitted in a two-stage strong and weak fitting state. According to the inventor of the present application, since the swing rod bends in response to a bending moment in actual fishing, a two-stage fitting state of a strong fitting state and a weak fitting state is formed between the large-diameter knot and the small-diameter knot. As a result, it was found that the small-diameter knots are securely fitted to the large-diameter knots without rotating or falling off. Moreover, since the diameter-reduced portion is provided in the large-diameter node, even if the small-diameter node is pulled out from the large-diameter node with a strong force, the small-diameter node comes into contact with the reduced-diameter node, so that the small-diameter node has a small diameter. Withdrawal of knots is regulated.

(2) It is preferable that each taper ratio satisfies T3 ≦ T1 <T2.

In this configuration, the second fitting convex portion is weakly fitted to the fitting concave portion, and the first fitting convex portion is strongly fitted.

(3) The taper ratio T1 is preferably set to be equal to the taper ratio T3.

In this configuration, the second fitting convex portion does not fit strongly with the fitting recess, but a weak fitting state is formed due to the bending of each node.

(4) The taper ratios T1 and T3 are preferably set to 0/1000 or more and 10/1000 or less.

In this configuration, the second fitting protrusion is fitted to the fitting recess with a necessary and sufficient fitting force to prevent the rotation and falling off.

(5) A first fitting step portion is formed at the boundary between the reduced diameter portion and the fitting recess, and the small diameter node has an outer diameter reduced axially forward from the second fitting convex portion. It is preferable to further have a second fitting step portion to be formed. In this case, the inner diameter of the first fitting step portion is set smaller than the outer diameter of the second fitting step portion.

In this configuration, when the small-diameter knot is pulled out from the large-diameter knot, the second fitting step portion comes into contact with the first fitting step portion, and the sliding of the small-diameter knot is surely restricted.

(6) A slide guide portion may be provided on the outside of the tip portion of the small diameter node to guide the slide of the small diameter node with respect to the large diameter node in contact with the reduced diameter portion.

In this configuration, when the small diameter node is pulled out from the large diameter node, even if the tip of the small diameter node collides with the inside of the large diameter node, the slide guide portion abuts on the reduced diameter portion. While guiding the slide of the small diameter node. Therefore, it is possible to smoothly pull out the knots having a small diameter.

(7) A chamfered portion may be formed at the tip of the small-diameter node.

In this configuration, when the small-diameter node is pulled out from the large-diameter node, the tip of the small-diameter node makes an acute angle contact with the inside of the large-diameter node, so that the tip of the small-diameter node is assumed to be large. The chamfer guides the slide of the small diameter node even if it comes into contact with the small diameter node. Therefore, it is possible to smoothly pull out the knots having a small diameter.

According to the present invention, only the two-stage fitting state is formed between the large-diameter knot and the small-diameter knot, and the knots are easily prevented from rotating or falling off in actual fishing. Further, the reduced diameter portion provided in the large-diameter knot easily regulates the excessive pulling out of the small-diameter knot. Therefore, an inexpensive swing rod is provided in which rotation, dropout, and sticking of each node are prevented in actual fishing.

FIG. 1 is an external perspective view of a swing rod according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing a fitting state of the fourth section and the fifth section according to the embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view of a main part of a swing rod according to a first modification of the embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view of a main part of the swing rod according to the first modification of the embodiment of the present invention. FIG. 5 is an enlarged cross-sectional view of a main part of a swing rod according to a second modification of the embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. Needless to say, the embodiment is only one aspect of the swing rod according to the present invention, and the embodiment may be changed without changing the gist of the present invention.

FIG. 1 is an external perspective view of a swing rod 10 according to an embodiment of the present invention.

The swing rod 10 is a so-called handle of a tamo, and a tamo net can be detachably attached to a boss 19 provided at the tip. The swing rod 10 has seven nodes 11 to 17 formed in a cylindrical shape (so-called seven-joint structure), and as shown in the figure, each section 11 to 17 is assembled in a swing manner. .. That is, a small-diameter node is inserted inside the large-diameter node, and the small-diameter node is slidable along the axial direction 18 with respect to the large-diameter node. The sections with the smallest outer diameter are referred to as the first section 11 and the second section 12, the seventh section 17 is particularly referred to as the original section 17, and the sixth section 16 is referred to as the original upper section 16. When the nodes 11 to 16 are housed inside the adjacent sections 12 to 17, that is, when all the sections 11 to 16 are housed in the original section 17, the boss 19 is fitted into the tip opening of the original section 17. It is designed to be used. Generally, the outer peripheral surface of the boss 19 is made of rubber, and the boss 19 also serves as a cap for storing the swing rod 10. The butt plug 42 is screwed into the rear end of the original node 16.

Each section 11-17 is molded in a known manner. For example, a resin sheet (prepreg) reinforced with carbon fiber is cut into a predetermined shape, wound around a mandrel, and then heat-treated at a predetermined temperature to obtain a knot of the desired shape. Is fired. By pulling out the mandrel after this heat treatment, each section 11 to 17 is formed as a part of the swing rod 10.

In general, the outer shape of each section 11 to 17 is gradually expanded from the front end side (left side in the figure) to the rear end side (right side in the figure) in the axial direction 18 with a pre-designed taper ratio. .. The inner diameter of the tip of the adjacent node having the larger outer diameter is designed to be smaller than the outer diameter of the rear end of the node having the smaller outer diameter. Therefore, for example, Section 4 14 (an example of the "small diameter section" described in the claims) is Section 5 15 (an example of the "large diameter section" described in the claims). Since the inner diameter of the tip portion 20 of the fifth section 15 is set to be smaller than the inner diameter of the rear end portion (not shown) of the fourth section 14 when extending from the axial direction 18 Is fitted and the extended state of the fourth section 14 with respect to the fifth section 15 is maintained. The same applies to the relationship between other adjacent large-diameter nodes and small-diameter nodes. In the present embodiment, the swing rod 10 has a seven-joint structure, but is not limited to such a structure, and is composed of a plurality of nodes, and the small-diameter nodes are arranged adjacent to each other inside the large-diameter nodes. , The structure may be such that both slide relatively in the axial direction 18.

In the present embodiment, the handle of the tamo is illustrated as the swing rod 10, but it goes without saying that the present invention is generally applied to the swing type fishing rod.

A feature of the swing rod 10 according to the present embodiment is a fitting structure in which the tip end portion of the large diameter node and the rear end portion of the small diameter node among the adjacent nodes are fitted. By fitting the two together with a simple structure as described later, the rotation of each section 11 to 16 in actual fishing and the unintentional dropout of the angler are surely prevented.

FIG. 2 is a diagram schematically showing a fitted state between the rear end portion 21 of the fourth section 14 and the tip end portion 20 of the fifth section 15.

The tip outer diameter 22 of the fifth section 15 is smaller than the rear end outer diameter. That is, the outer shape 23 of the fifth section 1 exhibits a wedge shape in which the outer diameter is gradually increased from the front end side 24 to the rear end side 25 in the axial direction 18. The taper ratio of the outer shape of the fifth section 15 is set to about 0.1 / 1000 to 5/1000.

A fitting recess 26 and a reduced diameter portion 27 are formed inside the tip portion 20 of the fifth section 15. These are integrally formed on the inner wall surface 28 of the fifth section 15. The inner wall surface 28 of the fifth section 15 corresponds to the outer shape of the mandrel and is inclined with a general taper ratio Λ. That is, in general, the inner diameter of the inner wall surface 28 of the fifth section 15 gradually increases from the front end side 24 to the rear end side 25. In the present embodiment, the taper ratio Λ is set to about 0.1 / 1000 to 5/1000.

The fitting recess 26 is formed on the tip side 24 continuously on the inner wall surface 28. The inner surface 29 of the fitting recess 26 is inclined as shown in the figure. That is, the inner diameter of the fitting recess 26 is gradually increased from the front end side 24 in the axial direction 18 toward the rear end side 25 with a taper ratio T1. In the present embodiment, the taper ratio T1 is set to 2/1000, but the taper ratio is not limited to this, and T1 ≦ 10/1000 may be used, and T1 = 0/1000. Good. That is, the taper ratio T1 can be appropriately set in the range of 0/1000 ≦ TI ≦ 10/1000.

The reduced diameter portion 27 is formed on the tip end side 24 in succession to the fitting recess 26. The reduced diameter portion 27 has an annular shape and is continuous with the tip 30 of the fifth section 15, and projects inward so as to reduce the inner diameter of the tip 30. The inner surface 31 of the reduced diameter portion 27 is along the axial direction 18, but a so-called draft may be set in order to facilitate the removal work of the mandrel during molding. The shape of the reduced diameter portion 27 is not limited to an annular shape as long as the inner diameter of the tip 30 is reduced. Since the reduced diameter portion 27 is formed, the rigidity of the opening peripheral edge portion of the tip 30 is improved.

In the present embodiment, since the reduced diameter portion 27 exhibits an annular shape, a step portion 32 (corresponding to the “first fitting step portion” described in the claims) at the boundary with the fitting recess 26. Is formed. In the present embodiment, the inner diameter 33 of the step portion 32 is outside the step portion 35 of the fourth section 14 (corresponding to the “second fitting step portion” described in the claims) described in detail later. The diameter is set smaller than 35. The effect of setting the inner diameter 33 of the step portion 32 to be smaller than the outer diameter 35 of the step portion 34 will be described later.

A first fitting convex portion 36 and a second fitting convex portion 37 are formed at the rear end portion 21 of the fourth section 14. These are integrally formed on the outer peripheral surface 38 of the fourth section 14. The outer diameter 39 of the fourth section 14 is set smaller than the inner diameter 33 of the reduced diameter portion 27 of the fifth section 15, and the first fitting convex portion 36 and the second fitting convex portion 37 are formed. As a result, the outer diameter of the rear end portion 21 of the fourth section 14 is expanded.

The first fitting convex portion 36 is formed at the rear end of the fourth section 14. The first fitting convex portion 36 has a truncated cone shape, and its outer peripheral surface 40 is inclined at a taper ratio T2. That is, the outer diameter of the first fitting convex portion 36 is gradually reduced from the rear end side 25 toward the front end side 24. In the present embodiment, the taper ratio T2 is set to 10/1000, but is not limited to this, and can be appropriately set in the range of 5/1000 to 20/1000. However, there is a relationship of T1 <T2 between the taper ratios T1 and T2.

A second fitting convex portion 37 is formed on the tip side 24 continuously with the first fitting convex portion 36. The outer peripheral surface 41 of the second fitting convex portion 37 is inclined at a taper ratio T3. That is, the outer diameter of the second fitting convex portion 37 is gradually reduced from the rear end side 25 toward the front end side 24. In the present embodiment, the taper ratio T3 is set to 2/1000, but is not limited to this, and is appropriately in the range of 0/1000 ≦ T3 ≦ 10/1000, which is about the same as the taper ratio T1. Can be set. However, there is a relationship of T2 <T3 between the taper ratios T2 and T3. In particular, in the present embodiment, the taper ratios T1, T2, and T3 are designed so that the relationship of T3 ≦ T1 <T2 is established.

The step portion 34 is formed in front of the second fitting convex portion 37 in the axial direction 18, that is, at the front end of the second fitting convex portion 37. The step portion 34 is formed by forming the front surface of the second fitting convex portion 37 on a steep wall surface. The outer diameter of the front surface of the second fitting convex portion 37 is set to be the outer diameter 35 of the step portion 34 and larger than the inner diameter 33 of the step portion 32.

The above is a description of the fitting state between the rear end portion 21 of the fourth section 14 and the tip end portion 20 of the fifth section 15, but the fitting state is the third section 13 and the fourth section. It also holds between large-diameter nodes and small-diameter nodes that are adjacent to each other, such as node 14. However, it is sufficient that the fitting state is established between any one set of adjacent large-diameter knots and small-diameter knots.

In the swing rod 10 according to the present embodiment, when a small-diameter knot slides with respect to an adjacent large-diameter knot, for example, the fourth knot 14 moves to the tip side 24 in the axial direction 18 with respect to the fifth knot 15. When slid, the swing rod 10 is extended. At this time, as shown in FIG. 2, the second fitting convex portion 37 and the first fitting convex portion 36 of the fourth section 14 are fitted so as to be pushed into the fitting recess 26 of the fifth section 15. It fits. Since the taper ratio T3 of the second fitting convex portion 37 and the taper ratio T1 of the first fitting convex portion 36 are set as described above, the first fitting convex portion 36 is relatively strong against the fitting concave portion 26. At the same time as fitting, the second fitting convex portion 37 fits relatively weakly.

In actual fishing, the swing rod 10 bends in response to a bending moment. Therefore, a two-stage fitting state of a strong fitting state and a weak fitting state is formed between the fifth section 15 and the fourth section 14. In the present embodiment, since the relationship of T3 ≦ T1 <T2 is established for each of the taper ratios T1, T2, and T3, the second fitting convex portion 37 is weakly fitted to the fitting recess 26. Then, the first fitting convex portion is strongly fitted. As a result, the fourth section 14 is prevented from falling off, the rotation around the axial direction 18 and the like are prevented, and the fifth section 15 is securely fitted. Moreover, in this swing rod 10, since the reduced diameter portion 27 is provided in the fifth section 15, even if the fourth section 14 is pulled out from the fifth section 15 with a strong force, the contracted portion 27 is provided. The fourth section 14 comes into contact with the diameter portion 27, and the fourth section 14 is not forcibly pulled out to the tip side 24. As a result, sticking between the 4th section 14 and the 5th section 15 is avoided.

In the present embodiment, the taper ratio T1 of the fitting recess 26 may be set to be equal to the taper ratio T3 of the second fitting protrusion 37. In this case, the second fitting convex portion 37 does not fit tightly to the fitting concave portion 26, but due to the bending of the fourth section 14 and the fifth section 15, the fitting is weakly fitted between the two. A state is formed. As a result, in actual fishing, the fourth section 14 is prevented from falling off or rotating, and the two sections 14 and 15 are more reliably prevented from sticking.

As described above, the taper ratios T1 and T3 are set to 0/1000 or more and 10/1000 or less. As a result, a necessary and sufficient fitting force is generated between the fitting recess 26 and the second fitting convex portion 37 in order to prevent the fourth section 14 from falling off or rotating.

A step portion 32 is formed at the boundary between the reduced diameter portion 27 of the fifth section 15 and the fitting recess 26, and a step portion 34 is formed at the fourth section 14, and in particular, the inner diameter of the step portion 32 is a step. Since it is set to be smaller than the outer diameter of the portion 34, when the fourth section 14 is pulled out from the fifth section 15, the step portion 34 comes into contact with the step portion 32, and the slide of the fourth section 14 slides. It is surely regulated, and the sticking between the 4th section 14 and the 5th section 15 is more surely avoided.

Next, a modified example of the swing rod 10 according to the present embodiment will be disclosed.

FIG. 3 is an enlarged cross-sectional view of a main part of the swing rod 50 according to the first modification of the present embodiment. The figure schematically shows the stored state of the swing rod 50.

In the figure, the former upper section 16 is housed inside the former section 17, and although it is not shown, all of the first section 11 to the fifth section 15 are housed inside the former upper section 16. There is. The lengths of the second section 12 to the fifth section 15 and the original upper section 16 are the same, and the first section 11 protrudes from the former upper section 16. The boss 19 is fitted to the tip of the original node 17.

The difference between the swing rod 50 according to the present modification and the swing rod 10 according to the embodiment is that the tip of the original upper section 16 corresponds to a bulge 43 (a “slide guide” described in the claims). ) Is formed. The bulging portion 43 is integrally formed with the original upper node 16. In this modified example, the bulging portion 43 has an outer shape that gently bulges outward in the radial direction as shown in the figure, and the outer diameter is the largest in the central portion along the axial direction 18. In this modification, the bulge size 44 is set to about 26 mm to 27 mm. However, the maximum outer diameter of the bulging portion 43 is smaller than the inner diameter of the reduced diameter portion 27 of the original node 17.

When the swing rod 50 is in the retracted state, that is, in a state where the first section 11 to the original upper section 16 are all housed in the original section 17, the contact portion 43 is shrunk inside the original section 17. It is arranged 25 on the rear end side of the diameter portion 27. When the original upper node 16 is pulled out from the original node 17 toward the tip side 24 from this state, the bulging portion 43 of the original upper node 16 comes into contact with the reduced diameter portion 27 of the original node 17. However, since the bulging portion 43 gently bulges in the radial direction as described above, the slide of the original upper section 16 is guided while abutting on the reduced diameter portion 27. Therefore, the original upper section 16 can be smoothly pulled out.

In this modified example, the bulging portion 43 is integrally formed on the original upper section 16, but instead, as shown in FIG. 4, the tip of the original upper section 16 is chamfered. You may. That is, as shown in the figure, a so-called C surface 45 may be formed at the tip corner portion of the original upper node 16.

When the original upper node 16 is pulled out from the original node 17 toward the tip side 24 by forming the C surface 45 in this way, the tip corner portion of the original upper node 16 comes into contact with the reduced diameter portion 27. However, since the tip corner portion of the original upper section 16 is in contact with the reduced diameter portion 27 at an acute angle, the C surface 45 guides the slide of the former upper section 16 while abutting on the reduced diameter portion 27. .. Therefore, the original upper section 16 can be smoothly pulled out. Instead of the C surface 45, a so-called R surface or other chamfering process may be performed.

FIG. 5 is an enlarged cross-sectional view of a main part of the swing rod 60 according to the second modification of the present embodiment. The figure schematically shows the stored state of the swing rod 60.

Similar to the swing rod 50 according to the first modification, the original upper section 16 is housed inside the original section 17, and although not shown, all of the first section 11 to the fifth section 15 are included. It is housed inside the former upper section 16.

The difference between the swing rod 60 according to the present modification and the swing rod 10 according to the embodiment is that the reduced diameter portion 27 of the large-diameter node (original node 17) is extended to the rear end side 25 of the axial direction 18. This is the point where the seat 46 on which the tip of the original upper section 16 is placed is formed. In this modification, the seat 46 is formed as a part of the reduced diameter portion 27, but a member separate from the reduced diameter portion 27 may be provided inside the tip portion of the original node 17.

In this modified example, when the swing rod 60 is in the retracted state, that is, in the state where the first section 11 to the former upper section 16 are all housed in the former section 17, the tip of the former upper section 16 is the seat 46. Supported by. Therefore, when the original upper section 16 is pulled out from the original section 17 toward the tip side 24 from this state, the original section 17 does not collide with the original upper section 16 and hinder the slide. Therefore, the original upper section 16 can be smoothly pulled out.

10 ... Swing rod 11 ... 1st section 12 ... 2nd section 13 ... 3rd section 14 ... 4th section 15 ... 5th section 16 ... Original upper section 17 ・ ・ ・ Original section 18 ・ ・ ・ Axial direction 20 ・ ・ ・ Tip part 21 ・ ・ ・ Rear end part 26 ・ ・ ・ Fitting recess 27 ・ ・ ・ Reduced diameter part 28 ・ ・ ・ Inner wall surface 29 ・・ ・ Inner surface 30 ・ ・ ・ Tip opening 31 ・ ・ ・ Inner surface 32 ・ ・ ・ Step 33 ・ ・ ・ Inner diameter 34 ・ ・ ・ Step 35 ・ ・ ・ Outer diameter 36 ・ ・ ・ First fitting convex part 37 ・ ・・ Second fitting convex part 38 ・ ・ ・ outer peripheral surface 40 ・ ・ ・ outer peripheral surface 41 ・ ・ ・ outer peripheral surface 43 ・ ・ ・ bulging part 44 ・ ・ ・ bulging size 45 ・ ・ ・ C surface 50 ・ ・ ・Rod 60 ・ ・ ・ Swing rod

Claims (7)

A swing rod that has a large-diameter knot and small-diameter knots arranged adjacent to each other inside the large-diameter knot, and the small-diameter knot slides relative to the large-diameter knot in the axial direction. hand,
The large-diameter knot has a fitting recess formed inside the tip thereof with a predetermined taper ratio T1 toward the rear in the axial direction to gradually increase the inner diameter, and is provided axially forward from the fitting recess. Has a reduced diameter portion that reduces the inner diameter of the tip
At the rear end of the small-diameter node, a first fitting convex portion that gradually reduces the outer diameter at a predetermined taper ratio T2 toward the front in the axial direction is formed, and from the first fitting convex portion. A swing rod provided forward in the axial direction and having a second fitting convex portion that gradually reduces the outer diameter at a predetermined taper ratio T3 different from the taper ratio T2 toward the front in the axial direction. The swing rod according to claim 1, wherein each taper ratio satisfies T3 ≦ T1 <T2. The swing rod according to claim 1 or 2, wherein the taper ratio T1 is equal to the taper ratio T3. The swing rod according to any one of claims 1 to 3, wherein the taper ratios T1 and T3 are set to 0/1000 or more and 10/1000 or less. A first fitting step portion is formed at the boundary between the reduced diameter portion and the fitting recess.
The small-diameter node further has a second fitting step portion whose outer diameter is reduced in the axially forward direction from the second fitting convex portion.
The swing rod according to any one of claims 1 to 4, wherein the inner diameter of the first fitting step portion is smaller than the outer diameter of the second fitting step portion. Any of claims 1 to 5, wherein a slide guide portion is provided on the outside of the tip portion of the small diameter node to abut the reduced diameter portion and guide the slide of the small diameter node with respect to the large diameter node. The swing rod described in. The swing rod according to any one of claims 1 to 5, wherein a chamfered portion is formed at the tip of the small-diameter node.

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