JP3228473U - Sanshin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sanshin capable of improving the operability of string tuning without modifying the paddle part. SOLUTION: A thread winding portion 20 is inserted into a pair of insertion holes 17A and 17B, an engaging tapered surface portion 25 engages with one inner peripheral surface of the pair of insertion holes 17A and 17B, and a tip portion of a rod portion 21. Is exposed to the outside of the side frame portion 16, and a pressing member 30 for pressing the outer surface of the side frame portion 16 is arranged at the tip end portion of the exposed rod portion 21. Further, between the outer surface of the side frame portion 16 and the pressing member 30, an urging member 32 (conical coil spring) for urging the side frame portion 16 and the pressing member 30 in a direction to separate them is interposed. The pressing member 30 presses the outer surface of the side frame portion 16 via the urging member 32. [Selection diagram] Fig. 5

Description

The present invention relates to a sanshin that can improve the operability of string tuning without modifying the paddle.

Sanshin, which is an Okinawan folk instrument, is generally provided with snake skin spread on the front and / or back openings of the body frame of the body, and the body, paddle, body and body. It is composed of three strings stretched over the paddle.

In this type of sanshin, the tension of the strings is adjusted (string adjustment) using a rod-shaped spool. The bobbin winding portion is inserted into an insertion hole formed at the tip of the paddle portion, and frictional resistance is generated between the inner peripheral surface of the insertion hole and the outer peripheral surface of the bobbin winding portion, so that the bobbin winding portion rotates. Is fixed. Therefore, for string tuning, the bobbin winder is rotated in the circumferential direction so as to pull in the string to increase the tension of the string, and the bobbin winder is strongly pushed into the insertion hole under an appropriate tension state for insertion. It is fixed with. That is, the string adjustment is performed by appropriately rotating or fixing the string by adjusting the fitting condition of the bobbin winding portion with respect to the insertion hole by the performer.

In addition, the performer actually plays the string and checks the tone of the string to rotate or fix the bobbin winding portion to determine the tension of the string and tune the string. If you become a skilled performer, you will be able to operate the bobbin and pluck the strings at the same time. String tuning requires the performer to perform the plurality of movements continuously or simultaneously, and the skill level is required for the performer, which is a very difficult movement for a beginner performer. Therefore, when a beginner tries to start the sanshin, he often gives up the sanshin in the middle due to the difficulty of tuning the strings.

Therefore, as a conventional technique for facilitating string adjustment, a pressing member is provided on the paddle portion, and the pressing member presses the bobbin winding portion inserted into the insertion hole in a direction perpendicular to the axial direction. Is known to fix the rotation of the bobbin winding portion. This pressing member includes a cylinder in which a metal ball is stored and fixed so that the tip slightly protrudes, an adjusting screw for adjusting the pressing force for pressing the cylinder against the side surface of the bobbin winding portion, and the adjusting screw. It has a support member and.

Japanese Unexamined Patent Publication No. 2011-17741

By the way, the paddle is formed by extending from wood such as red wood, rosewood, flower forest or ebony in a rod shape in addition to the genus Persimmon of the family Ebenaceae. The base end of the paddle is fitted inside the body of the sanshin, and the paddle is detachably fixed and supported on the body with a part of the base exposed to the outside from the body. In the case of a performer with a high degree of taste, the material of the paddle is made of high-grade wood to improve the appearance of his sanshin. In general, it is not preferable to add a predetermined member to the paddle. On the other hand, the thread-wound portion is often positioned as a consumable item as compared with the rod portion, and it tends to be allowed to be modified or added with other members.

In the three lines of Patent Document 1, a pressing member is added by processing a hole in the paddle portion, which deteriorates the appearance (aesthetics or appearance, etc.) of the paddle portion and impairs the value of the paddle portion. Further, the pressing member of Patent Document 1 can increase the frictional force between the paddle portion and the bobbin winding portion, but it merely increases the frictional force and it is impossible to finely adjust the frictional force. In the three wires of Patent Document 1, when the performer adjusts the strings by appropriately rotating or fixing the thread winding portion, an excessive force is required for the rotation operation of the thread winding portion and the thread winding portion is at an appropriate rotation position. It was difficult to fix the string, and there was room for improvement in terms of string tuning operability.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a sanshin capable of improving the operability of string tuning without modifying the paddle part.

The above-mentioned object of the present invention is achieved by the following configuration.
(1) A long rod, a window hole formed at the tip of the rod and arranged at the center in the width direction, and a pair of side frame portions arranged on both sides of the window hole in the width direction. , A rod portion formed in a rod shape and arranged at the tip portion, a knob portion arranged at the base end portion, and a tapered portion formed between the rod portion and the knob portion and formed in a tapered shape. The pair includes a thread winding portion having an engaging tapered surface portion whose diameter is reduced toward the portion, and a pair of insertion holes formed over both the pair of side frame portions and arranged concentrically with each other. One of the insertion holes is formed in a tapered shape and has a diameter reduced inward in the width direction of the rod portion corresponding to the engaging tapered surface portion, and the thread winding portion is inserted into the pair of insertion holes. In a state where the engaging tapered surface portion is engaged with one inner peripheral surface of the pair of insertion holes and the tip portion of the rod portion is exposed to the outside of the side frame portion, the exposed tip portion of the rod portion is exposed. A three-wire system in which a pressing member for pressing the outer surface of the side frame portion is arranged.
(2) The thread winding portion, the tip portion of the rod portion is formed with a screw groove, and the pressing member is formed with a screw hole screwed into the screw groove, according to (1). Three lines.
(3) An urging member for urging the side frame portion and the pressing member in a direction for separating the side frame portion from the pressing member is interposed between the outer surface of the side frame portion and the pressing member. The three lines according to (1) or (2), wherein the outer surface of the side frame portion is pressed through the urging member.

According to the configuration of (1) above, the bobbin winding portion is inserted into the pair of insertion holes, the engaging tapered surface portion engages with one inner peripheral surface of the pair of insertion holes, and the tip portion of the rod portion is the side frame. When exposed to the outside of the portion, the tip of the exposed rod portion is used together with a pressing member for pressing the outer surface of the side frame portion (for example, an urging member (for example, a conical push spring)). Good) is arranged.
Therefore, the pressing force on the outer surface of the side frame portion can be arbitrarily set by arbitrarily adjusting the axial position of the pressing member provided on the bobbin winding portion on the rod portion. As a result, a force that pulls the bobbin winding portion into the paddle portion is generated as a reaction force of the pressing force, and the frictional force between the engaging tapered surface portion of the bobbin winding portion and the tapered inner peripheral surface of the insertion hole is arbitrary. Can be adjusted to. As a result, the resistance force in the rotation direction of the thread winding portion can be arbitrarily and continuously set according to the preference of the performer. Further, for example, after the string adjustment is completed, the axial position of the pressing member in the rod portion is moved inward to increase the pressing force with the outer surface of the side frame portion, so that the bobbin winding portion is firmly fixed to the rod portion and the string is formed. It is possible to maintain the tension of the strings and prevent the strings from loosening. In this way, it is possible to provide a sanshin capable of improving the operability of string tuning without modifying the paddle portion.
According to the configuration (2) above, a screw groove is formed at the tip of the rod portion of the bobbin winding portion, and a screw hole screwed into the screw groove is formed at the pressing member. Therefore, since the axial position of the pressing member on the rod portion is easily and surely finely adjusted as if the screw is turned, the operability of string adjustment can be further improved.
According to the configuration of (3) above, an urging member for urging the outer surface of the side frame portion and the pressing member in a direction for separating the side frame portion and the pressing member is interposed, and the pressing member is interposed. , Press the outer surface of the side frame portion via the urging member. Therefore, the pressing force between the pressing member and the outer surface of the side frame portion can be easily and freely increased or decreased, so that the bobbin winding portion can be firmly fixed by the paddle portion or more easily. The operability of string tuning can be further improved by making fine adjustments.

According to the present invention, the operability of string tuning can be improved without modifying the paddle portion.

The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through the embodiments described below (hereinafter referred to as "embodiments") with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating three lines of an embodiment according to the present invention. FIG. 2 is a cross-sectional view illustrating the configuration of the bobbin winding portion. FIG. 3 is a front view for explaining the engagement structure of the paddle portion and the bobbin winding portion shown in FIGS. 1 and 2. FIG. 4 is a front view illustrating how the thread winding portion is attached to the rod portion. FIG. 5 is a front view illustrating a state in which the bobbin winding portion is attached to the paddle portion.

Hereinafter, embodiments of the three lines according to the present invention will be described in detail with reference to the drawings.
The shamisen, which is an Okinawan folk song instrument, will be described below as being included in the types of "shamisen" instruments that are widely known, including in the Tohoku region.

<Overall composition of Sanshin>
First, the overall configuration of the three wires 10 according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view illustrating the three lines 10 of the present embodiment.

As shown in FIGS. 1 and 2, the sanshin 10 according to the present embodiment is widely known as a string 18 musical instrument of Okinawan folk songs. The Okinawa sanshin 10 is composed of a body portion 11, a paddle portion 14, a string 18 stretched over the body portion 11 and the paddle portion 14, and a sanshin pick (not shown). To.

The body portion 11 includes a wooden body frame 12 formed in a substantially rectangular ring shape and having a cavity inside thereof, and a pair of vibrating membrane bodies 13 and 13 that close both openings (not shown) of the cavity of the body frame 12. It is composed. That is, the cavity of the body frame 12 is closed by a pair of vibrating film bodies 13 and 13 on the front and back sides to be in an airtight state, and the body portion 11 functions as a resonance space of the three wires 10. The vibrating membrane body 13 is formed of, for example, a sheet member made of synthetic resin or cloth, or a snake skin.

In the present embodiment, the pair of vibrating membrane bodies 13 and 13 are provided at both openings of the cavity of the body frame 12, but the present invention is not limited to this. Only one of the two openings (for example, the front side of the body portion 11) may be used. Further, the back surface may not be provided with the vibrating membrane body 13 of the present embodiment, but instead may be provided with a snake skin attached. Further, in the present embodiment, the horizontal dimension of the body frame 12 is set to 190 mm, the vertical dimension is set to 200 mm, and the height dimension is set to 80 mm. Further, the wall thickness dimension is set to 20 mm.

The paddle portion 14 is provided so as to extend in a long shape (rod shape) from wood such as red wood, rosewood, flower forest or ebony, in addition to the genus Persimmon of the family Ebenaceae. The base end portion of the paddle portion 14 is inserted into the body portion 11, and the base end portion is detachably fixedly supported to the body portion 11 in a state where a part of the base end portion is exposed to the outside from the body portion 11. Will be done.

A spool portion 20 (called "Karakui" in the dialect in Okinawa) is provided at the tip of the paddle portion 14 (see FIGS. 2 and 3). In the present embodiment, the thread winding portions 20 have three thread winding portions 20 arranged alternately on the left and right along the width direction thereof. A string 18 is wound around the bobbin 20. The string 18 is made of, for example, a polyamide synthetic fiber, a synthetic resin fiber such as a fluororesin, or silk, and is stretched and fixed over the body portion 11 and the paddle portion 14.

<About the configuration of the bobbin winding part>
Next, the configuration of the bobbin winding portion 20 will be described with reference to FIG. FIG. 2 is a cross-sectional view illustrating the configuration of the bobbin winding portion 20.

The bobbin winder portion 20 is formed in an elongated conical shape (rod shape) as a whole, and includes a rod portion 21 arranged at the tip portion and a knob portion 24 arranged at the substrate portion. .. Further, the thread winding portion 20 is further provided with an engaging tapered surface portion 25 which is arranged between the knob portion 24 and is formed in a tapered shape and whose diameter is reduced toward the tip portion. The knob portion 24 is formed to have a larger diameter as a whole than the engaging tapered surface portion 25, and the engaging tapered surface portion 25 is formed to have a larger diameter as a whole than the rod portion 21.

A step portion 26 is arranged between the engaging tapered surface portion 25 and the knob portion 24. The knob portion 24, the step portion 26, and the engaging tapered surface portion 25 are provided from wood in the same manner as the paddle portion 14, and these portions are integrally formed (hereinafter, the portion is also referred to as a bobbin main body portion 20A). The knob portion 24 is formed in a polygonal shape in a radial cross-sectional view, has a plurality of corner portions, and is provided so that the performer can easily grip and rotate with a finger.

The rod portion 21 is made of a member separate from the thread winding main body portion 20A, and is provided in the shape of a straight rod from a metal material such as aluminum or brass in the present embodiment. A fixing hole 27 along the axial direction is formed on the tip surface of the bobbin main body 20A, and the rod portion 21 is fixedly supported by being inserted into the fixing hole 27 at its base end. Further, when the rod portion 21 is assembled to the spool main body portion 20A, a tool such as a drill is brought into contact with the portion of the engaging tapered surface portion 25 near the step portion 26 in the assembled state. Then, the tool penetrates the rod portion 21 together with the rod portion 21 in the radial direction to form the fixing pin hole 28. A metal pin (not shown) is inserted into the fixing pin hole 28, and the insertion of this pin prevents the relative rotation of the bobbin main body portion 20A and the rod portion 21 to realize a strong fixing. ..
In this embodiment, the diameter of the rod portion 21 is set to about 3 mm. Further, an adhesive may be applied to the surface of the rod portion 21 when it is inserted into the fixing hole 27 at its base end or when a pin is inserted into the fixing pin hole 28. In this case, the rod portion 21 or the pin is more firmly fixed and supported. The diameter of the metal pin is set to about 1 mm.

A support pin hole 22 for attaching the end portion of the string 18 is formed in the intermediate portion of the rod portion 21. With the end of the string 18 inserted through the support pin hole 22, the pincushion portion 24 of the bobbin winding portion 20 is rotated by the performer. By this rotation operation, each of the strings 18 is wound or unwound on the spool 20 to adjust the strings. Further, in the present embodiment, a screw groove 23 is formed at the tip of the rod portion 21 of the bobbin winding portion 20. A pressing member 30 (described below) is attached to the screw groove 23.
In this embodiment, the diameter of the support pin hole 22 is set to about 1 mm. The length of the screw groove 23 is about 10 mm, and the screw diameter is set to about M3.

<About the engagement structure of the paddle and the bobbin and its attachment>
Next, the engaging structure of the paddle portion 14 and the bobbin winding portion 20 and their attachment will be described with reference to FIGS. 3 to 5. FIG. 3 is a front view illustrating the engagement structure of the paddle portion 14 and the bobbin winding portion 20 shown in FIGS. 1 and 2. FIG. 4 is a front view illustrating how the spool portion 20 is attached to the paddle portion 14. FIG. 5 is a front view illustrating a state in which the spool portion 20 is attached to the paddle portion 14.
In addition, in FIG. 4 and FIG. 5, for convenience of illustration, only one pair out of a plurality of (three in the present embodiment) pairs of insertion holes 17A and 17B is shown, and the other pairs are omitted.

As shown in FIGS. 3 to 5, one window hole 15 arranged at the central portion in the axial direction is formed at the tip end portion of the paddle portion 14. The window hole 15 is formed so as to penetrate in the thickness direction of the paddle portion 14. A pair of side frame portions 16 (a pair of left and right facing wall portions) are arranged on both sides of the window hole 15 in the width direction. Then, a pair of insertion holes 17A and 17B are formed over both of the pair of side frame portions 16 in the width direction, and are arranged concentrically with each other. In the present embodiment, a pair of insertion holes 17A and 17B in the width direction are arranged side by side in a plurality of pairs (three in the present embodiment) along the longitudinal direction of the paddle portion 14.

For example, in the pair of insertion holes 17A and 17B in the width direction arranged in the middle of the three in the longitudinal direction, the left side (one side) 17A of the pair of insertion holes 17A and 17B is formed in a tapered shape and is formed on the engaging tapered surface portion 25. Correspondingly, the diameter of the paddle portion 14 is reduced inward in the width direction. The right side (other side) 17B of the pair of insertion holes 17A and 17B is formed by reducing the diameter toward the outside in the width direction at the same inclination angle as the left side insertion hole 17A (see FIGS. 4 and 5). Further, the insertion hole 17A on the left side is formed to have a larger diameter than the insertion hole 17B on the right side as a whole.
In the present embodiment, the insertion hole 17B on the right side is also formed in a tapered shape like the insertion hole 17A on the left side, but the present invention is not limited to this. As described below, if the rod portion 21 of the thread winding portion 20 can be inserted, various shapes such as a drilled hole (straight hole) can be appropriately adopted.

Further, as shown in FIG. 3, in each of the pair of axial insertion holes 17A and 17B arranged on the longitudinal end side and the longitudinal proximal end side of the three, the right insertion hole 17A is provided on the engaging tapered surface portion 25. Correspondingly, it is formed in a tapered shape and has a diameter larger than that of the insertion hole 17B on the left side thereof. Therefore, in the pair of insertion holes 17A and 17B in the axial direction in the middle in the longitudinal direction, the bobbin 20 is inserted and assembled from the left side to the right side. On the other hand, in each of the pair of axially inserted insertion holes 17A and 17B on the longitudinal end side and the longitudinal proximal end side, the bobbin 20 is inserted and assembled from the right side to the left side. Therefore, the three bobbin winding portions 20 are arranged alternately on the left and right in the longitudinal direction of the paddle portion 14.

As shown in FIGS. 4 and 5, when the spool portion 20 is attached to the pair of insertion holes 17A and 17B in the width direction, the spool portion 20 is inserted into the pair of insertion holes 17A and 17B. Then, the engaging tapered surface portion 25 engages with one inner peripheral surface of the pair of insertion holes 17A and 17B, and the rod portion 21 passes through the other of the pair of insertion holes 17A and 17B. At this time, due to the engagement between the engaging tapered surface portion 25 and one of the inner peripheral surfaces of the pair of insertion holes 17A and 17B, frictional resistance (friction force) is generated on the engaging surface, and the bobbin winding portion 20 rotates. It is suppressed. Further, in a state where the rod portion 21 passes through the other of the pair of insertion holes 17A and 17B and the tip portion of the rod portion 21 is exposed to the outside of the side frame portion 16, the exposed rod portion 21 is on the side of the tip portion. A pressing member 30 for pressing the outer surface of the frame portion 16 is attached (arranged).
In the present embodiment, as described below, the pressing member 30 is the reaction force of the urging member 32 (conical push spring) disposed between the outer surface of the side frame portion 16 and the pressing member 30. As a result, the frictional force between the engaging tapered surface portion 25 of the bobbin winding portion 20 and the tapered inner peripheral surface of the insertion hole 17A can be increased by pressing the outer surface of the side frame portion 16.

The pressing member 30 of the present embodiment is a bag nut, and a screw hole 31 for being screwed into the screw groove 23 of the rod portion 21 of the bobbin winding portion 20 is formed. The pressing member 30 is formed in a dome shape on the side opposite to the seating surface of the pressing member 30 so that the tip of the rod portion 21 of the spool portion 20 does not protrude from the tip surface of the pressing member 30 and surrounds the tip of the rod portion 21. It is provided to be crowded. The pressing member 30 is screwed and fixed in the screw groove 23 through the screw hole 31 and attached.
The screw diameter of the screw hole 31 of the pressing member 30 is set to about M3 corresponding to the screw groove 23 of the rod portion 21.

Further, an urging member 32 that urges the side frame portion 16 and the pressing member 30 in a direction to separate them is interposed between the outer surface of the side frame portion 16 and the pressing member 30. The urging member 32 is a conical coil spring (push spring), and the pressing member 30 is inserted into and attached to the rod portion 21 at its inner diameter portion before being attached to the tip portion of the rod portion 21. Further, when the urging member 32 is inserted into the rod portion 21, it is sandwiched by a pair of washers 33, 33. The pressing member 30 presses the outside (outer surface) of the side frame portion 16 via the urging member 32.
The urging member 32 is arranged so that its small diameter portion faces the pressing member 30 side. The outer diameter of the urging member 32 is set to about 3 mm on the small diameter side and about 8 mm on the large diameter side. The thickness of the washer 33 is set to about 0.5 mm. Alternatively, the wire diameter of the urging member 32 (conical coil spring) is 0.5 mm, and the outer diameter is about 4.0 mm on the small diameter side, about 10.0 mm on the large diameter side, and more freely. The length may be set to 15.0 mm. Further, the pressure (elastic modulus) in this case is preferably set to about 0.245 N / mm.

<Advantages of Sanshin according to this embodiment>
As described above, according to the present embodiment, the bobbin winding portion 20 is inserted into the pair of insertion holes 17A and 17B, and the engaging tapered surface portion 25 engages with one inner peripheral surface of the pair of insertion holes 17A and 17B. In addition, with the tip of the rod portion 21 exposed to the outside of the side frame portion 16, a pressing member 30 for pressing the outer surface of the side frame portion 16 is arranged at the tip of the exposed rod portion 21. To.
At this time, the pressing member 30 presses the outer surface of the side frame portion 16 by the reaction force of the urging member 32 (conical push spring) arranged between the outer surface of the side frame portion 16 and the pressing member 30. It should be configured to be possible.

Therefore, the pressing force on the outer surface of the side frame portion 16 can be arbitrarily set by arbitrarily adjusting the axial position of the pressing member 30 provided on the spool portion 20 in the rod portion 21. As a result, a force for pulling the spool portion 20 into the paddle portion 14 is generated as a reaction force of the pressing force, and between the engaging tapered surface portion 25 of the spool portion 20 and the tapered inner peripheral surface of the insertion hole 17A. The frictional force of the can be adjusted arbitrarily. As a result, the resistance force of the bobbin winding portion 20 in the rotation direction can be arbitrarily and continuously set according to the preference of the performer. Further, for example, after the string adjustment is completed, the axial position of the pressing member 30 on the rod portion 21 is moved inward to increase the pressing force with the outer surface of the side frame portion 16 so that the bobbin winding portion 20 is firmly attached to the rod portion 14. It can be fixed to maintain the tension of the string 18 and prevent the string 18 from loosening. In this way, it is possible to provide the sanshin 10 capable of improving the operability of string tuning without modifying the paddle portion 14.

Further, according to the present embodiment, a screw groove 23 is formed at the tip of the rod portion 21 of the spool portion 20, and a screw hole 31 screwed into the screw groove 23 is formed at the pressing member 30. To. Therefore, since the axial position of the pressing member 30 on the rod portion 21 is easily and surely finely adjusted so as to turn the screw, the operability of string adjustment can be further improved.

Further, according to the present embodiment, an urging member 32 for urging the side frame portion 16 and the pressing member 30 in a direction separating the side frame portion 16 is interposed between the outer surface of the side frame portion 16 and the pressing member 30. The pressing member 30 presses the outer surface of the side frame portion 16 via the urging member 32. Therefore, the pressing force between the pressing member 30 and the outer surface of the side frame portion 16 can be easily and freely increased or decreased, so that the bobbin winding portion 20 can be firmly fixed by the paddle portion 14. , It is possible to further improve the operability of string tuning by making fine adjustments more easily.

Although the description of the specific embodiment is completed above, the embodiment of the present invention is not limited to the above embodiment, and can be appropriately modified or improved.
For example, in the above embodiment, the conical coil push spring (coil spring) has been described as the urging member (32), but the present invention is not limited to this. In addition to elastic members such as leaf springs, soft member cushioning materials and the like can be appropriately applied. Further, these elastic members or cushioning materials may be provided integrally with the pressing member (30).
Further, although the bag nut has been described as the pressing member (30), the present invention is not limited to this. A nut through which a normal screw hole is penetrated may be used, and the nut may be not limited to a metal nut but may be made of a synthetic resin or the cushion material itself.

10: Sanshin 11: Body 12: Body frame 13: Vibrating membrane 14: Rod 15: Window hole 16: Side frame 17A: Insertion hole 17B: Insertion hole 18: String 20: Pincushion 20A: Pincushion body 21 : Rod part 22: Support pin hole 23: Screw groove 24: Knob part 25: Engagement tapered surface part 26: Step part 27: Fixing hole 28: Fixing pin hole 30: Pressing member 31: Screwing hole 32: Biasing Member 33: Washer

Claims (3)

With a long paddle and
A window hole formed at the tip of the paddle and arranged at the center in the width direction,
A pair of side frame portions arranged on both sides in the width direction of the window hole,
A rod portion formed in a rod shape and arranged at the tip portion, a knob portion arranged at the base end portion, and a tapered portion formed between the rod portion and the knob portion and formed in a tapered shape. A thread winding portion having an engaging tapered surface portion whose diameter is reduced toward
Including a pair of insertion holes formed over both of the pair of side frames and arranged concentrically with each other.
One of the pair of insertion holes is formed in a tapered shape and has a diameter reduced inward in the width direction of the paddle portion corresponding to the engaging tapered surface portion.
The thread winding portion is inserted into the pair of insertion holes, the engaging tapered surface portion engages with one inner peripheral surface of the pair of insertion holes, and the tip end portion of the rod portion is outside the side frame portion. In the exposed state, a pressing member for pressing the outer surface of the side frame portion is arranged at the tip end portion of the exposed rod portion.
Sanshin. A screw groove is formed at the tip of the rod portion of the thread winding portion.
A screw hole to be screwed into the screw groove is formed in the pressing member.
The three lines according to claim 1. An urging member for urging the side frame portion and the pressing member in a direction separating the side frame portion is interposed between the outer surface of the side frame portion and the pressing member.
The pressing member presses the outer surface of the side frame portion via the urging member.
The three lines according to claim 1 or 2.

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