Coupling separation device and method of assembling the same

Abstract

To achieve both connection force (maximum holding axial force) of a first structure and a second structure and separability of the first structure and the second structure.SOLUTION: A coupling separation device 1 for separably connecting a first structure and a second structure includes: a shaft member 2 provided on the first structural body side; three or more coupling members 4A to 4D provided on the second structural body side and disposed around a flange portion 2c of the shaft member; a restraint member 5 that restrains the coupling members so as not to move in a radial direction orthogonal to an axial direction; and a release member 6 that releases restraint of the restraint member. Restriction portions 4b1 and 4b2 are provided on an inner wall side of the coupling members, where the restraint member restricts the first structure and the second structure from moving in a direction away from each other along the axial direction by contacting the flange portions. When viewed from the axial direction, a shape of a radially outer end of the flange portion has a straight line shape, and when viewed from the axial direction, a shape of the radially inner end of the restricting portion is a straight line shape that is approximately parallel to the straight line shape of the flange portion.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a connecting and separating device and a method for assembling the same.

Background Art

[0002] Conventionally, a connecting and separating device for separably connecting a first structure and a second structure has been known. For example, Patent Document 1 discloses a spacecraft separation mechanism (connecting and separating device) including circular flanges (flange portions) provided at one ends of shaft members of two spacecrafts (first structure and second structure), and a pair of two clamp bands (connecting members) each having a half circumference for sandwiching and wrapping the outer peripheral portions of these flanges in a state where the flanges are abutted against each other. In this spacecraft separation mechanism, each end of the two clamp bands is coupled to each other by bolts (constraining members), and by cutting the two bolts with a bolt cutter (releasing member) that cuts with gunpowder, the flanges of the two spacecrafts constrained by the clamp bands can be separated, and the two spacecrafts are separated.

[0003] Also, for example, Patent Document 2 discloses a coupling and separating device (connecting and separating device) for separably coupling structures of rockets (first structure and second structure). This coupling and separating device includes a coupling bolt (shaft member) provided on one structure side, and a pair of two split nuts (connecting members) provided on the other structure side and divided into half circumferences. In this coupling and separating device, the coupling bolt is screwed into the split nut in a state of passing through both structures to couple the two structures. The two split nuts are constrained by a nut holder (constraining member) so as not to move in the radial direction, and when a linear squib (releasing member) is actuated, the nut holder is detached from the split nut. Thereby, the constraint of the split nut is released, the screwing engagement between the split nut and the coupling bolt is released, and the two structures are separated from each other.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-153800 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-292250 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] However, it has been difficult to achieve both the connection strength (maximum holding axial force) between the first structure and the second structure and the separability between the first structure and the second structure. [Means for Solving the Problems]

[0006] One aspect of the present invention is a connecting and separating device for separably connecting a first structure and a second structure, comprising a shaft member provided on the first structure side, three or more connecting members provided on the second structure side and arranged around a flange portion of the shaft member, a restraining member for restraining the three or more connecting members from moving in a radial direction orthogonal to the axial direction, and a releasing member for releasing the restraint of the restraining member. On the inner wall side of the three or more connecting members, there is provided a regulating portion for regulating the first structure and the second structure from moving in a direction of separating from each other along the axial direction by abutting against the flange portion. The shape of the radially outer end of the flange portion when viewed from the axial direction is a linear shape, and the shape of the radially inner end of the regulating portion when viewed from the axial direction is a linear shape substantially parallel to the linear shape of the flange portion. In this aspect, three or more connecting members provided on the second structure side are arranged around the flange portion of the shaft member provided on the first structure side, and the three or more connecting members are restrained by a restraining member so as not to move in the radial direction, whereby the first structure and the second structure are connected. At the time of connection, the restricting portion provided on the inner wall side of the connecting member abuts against the flange portion of the shaft member, thereby restricting the first structure and the second structure from separating from each other in the axial direction. The connection force between the two structures at this time can be evaluated by the force (hereinafter referred to as "maximum holding axial force") that holds the first structure and the second structure so as not to move in the direction of separating from each other along the axial direction. On the other hand, when the restraint of the restraint member is released by the release member, the three or more connecting members become movable in the radial direction. Then, when the restricting portion of the three or more connecting members moves radially outward from the flange portion of the shaft member, the first structure and the second structure can be separated from each other along the axial direction, and the two structures are separated. Therefore, when the restraint of the restraint member is released by the release member, it is required that the restricting portion of the three or more connecting members is not caught by the flange portion of the shaft member and the two structures can be stably separated. The maximum holding axial force of the connection and separation device increases as the contact portion between the restricting portion of the connecting member and the flange portion of the shaft member becomes wider. Therefore, the larger the height of the flange portion of the shaft member (the length of the flange portion in the radial direction from the shaft portion of the shaft member) and the height of the restricting portion of the connecting member (the radial length of the portion in contact with the flange portion), the larger the maximum holding axial force. However, the larger these heights are, the longer the distance that the connecting member has to move radially outward to release the restraint of the restraint member. Therefore, when the restraint of the restraint member is released, the restricting portion of the connecting member is likely to be caught by the flange portion of the shaft member, and the separability deteriorates. Therefore, in order to increase the maximum holding axial force of the connection and separation device while suppressing the deterioration of the separability, it is effective to increase the circumferential width of the contact portion between the restricting portion of the connecting member and the flange portion of the shaft member. Many conventional connecting and separating devices are configured such that a circular flange portion (the radially outer end of the flange portion has a curved shape when viewed in the axial direction) is provided on a cylindrical shaft member, and two connecting members, each covering a half circumference, are arranged around the flange portion. According to this configuration, since the regulating portions of the two connecting members abut against the entire circumference of the circular flange portion, the circumferential width of the contact portion between the regulating portion of the connecting member and the flange portion of the shaft member can be maximized. Therefore, it is possible to obtain a large maximum holding axial force. However, in the conventional configuration, the shape of the radially inner end of the regulating portion when viewed in the axial direction is a curved shape following the side surface of the cylindrical shaft member, and it is configured such that the entire radially inner end of the regulating portion contacts along the side surface of the shaft member during connection. In this configuration, the curved shape of the radially inner end of the regulating portion when viewed in the axial direction has a larger curvature than the curved shape of the radially outer end of the flange portion. Therefore, when the connecting member moves radially during restraint release, even if it moves a distance corresponding to the height of the flange portion of the shaft member or the height of the regulating portion of the connecting member, the entire radially inner end of the regulating portion cannot be moved to the outside of the flange portion. Specifically, even if the connecting member moves this distance radially during restraint release, both circumferential ends of the radially inner end of the regulating portion cannot be moved to the outside of the flange portion. Therefore, when the restraint is released, both circumferential ends of the radially inner end of the regulating portion are likely to be caught by the flange portion, resulting in poor separability. In this aspect, the shape of the radially outer end of the flange portion when viewed in the axial direction is a straight line shape, and the shape of the radially inner end of the regulating portion when viewed in the axial direction is a straight line shape substantially parallel to the straight line shape of the flange portion. According to this, the distance for the regulating portion of each connecting member to move radially outward from the flange portion of the shaft member during restraint release can be made shorter than in the conventional configuration. Therefore, it becomes less likely that the radially inner end of the regulating portion is caught by the flange portion during restraint release, and the separability can be improved. In adopting this configuration, it may be difficult to ensure a high maximum holding axial force. Therefore, in this embodiment, by arranging three or more connecting members around the flange portion, a higher holding axial force is ensured than in the conventional configuration where only two connecting members are arranged around the flange portion. The maximum holding axial force is the axial force at which the tension of the restraining member increases due to the radial movement of the connecting member by the axial force and the restraining member breaks. It can be derived from elementary mechanics that the tension generated in this restraining member decreases as the number of connecting members increases. According to this embodiment, it is possible to achieve both the connecting force (maximum holding axial force) between the first structural body and the second structural body and the separability between the first structural body and the second structural body.

[0007] In the connecting and separating device, a biasing member that biases the restraining member from the radially inner side to the radially outer side may be provided. According to this embodiment, at the time of restraint release, the biasing force of the biasing member can push the restraining member from the radially inner side to the radially outer side. As a result, when the three or more connecting members move radially outward at the time of restraint release, it becomes difficult for the restraining member to interfere with the movement, and higher separability can be achieved.

[0008] In the connecting and separating device, the biasing member may bias the restraining member via at least one of the three or more connecting members by biasing the at least one connecting member from the radially inner side to the radially outer side. According to this, at the time of restraint release, at least one connecting member can also be pushed from the radially inner side to the radially outer side by the biasing force of the biasing member. As a result, the biasing force of the biasing member can also be used as a force for moving the at least one connecting member radially outward at the time of restraint release, so that higher separability can be achieved.

[0009] In the connecting and separating device, the release member may be a dividing member that divides a predetermined circumferential position of the restraining member, and the biasing member may bias the restraining member in a direction in which the divided portion of the restraining member expands. According to this aspect, when the predetermined circumferential position of the restraining member is divided by the dividing member which is the releasing member to release the restraint, the restraining member is pushed and expanded in the direction in which the divided portion of the restraining member expands by the biasing force of the biasing member. According to this, when the three or more connecting members move radially outward at the time of releasing the restraint, it becomes difficult for the restraining member to obstruct the movement, and higher separability can be realized.

[0010] In the connecting and separating device, a second shaft member provided on the second structure side may be provided. The three or more connecting members may be arranged around both the flange portion of the shaft member and the second flange portion of the second shaft member. On the inner wall side of the three or more connecting members, a second restricting portion may also be provided to restrict the first structure and the second structure from moving away from each other in the axial direction by contacting the second flange portion. The shape of the radially outer end of the second flange portion when viewed from the axial direction may be a linear shape, and the shape of the radially inner end of the second restricting portion when viewed from the axial direction may be a linear shape substantially parallel to the linear shape of the flange portion. In the connecting and separating device according to this aspect, the shaft member on the first structure side and the second shaft member on the second structure side can be connected by the three or more connecting members. Moreover, since the configuration between the second shaft member and the three or more connecting members is the same as the configuration between the shaft member and the three or more connecting members described above, while realizing a high maximum holding axial force, the regulating portion of the connecting member is less likely to be caught by the flange portion of the second shaft member, so that high separability can be obtained.

[0011] In the connecting and separating device, at least one of the shaft member and the second shaft member may be formed such that the side surface of the shaft portion surrounded by the three or more connecting members is a plane facing each of the connecting members. According to this aspect, when the radially inner end shape of the restricting portion when viewed from the axial direction is a linear shape, the radially inner end of the restricting portion can be brought into contact along the side surface of the shaft member during connection. Thereby, the contact area between the shaft member and the connecting member is ensured, the integrity during connection is improved, and a stronger connection can be easily realized. In this aspect, as the shaft member, one in which the cross-sectional shape of the shaft portion surrounded by the three or more connecting members is a triangular shape, a quadrangular shape, a pentagonal shape or more with sides corresponding to the number of connecting members can be used.

[0012] In the connecting and separating device, the outer shape when the three or more connecting members are arranged around the flange portion of the shaft member may be a cylindrical shape. According to this aspect, since the outer shapes of the three or more connecting members become cylindrical shapes during connection, when a restraining member is arranged and restrained on the outer circumferences of the three or more connecting members, a situation where the corners of the connecting members hit the restraining member can be avoided. Thereby, it is possible to suppress a problem in which the restraint by the restraining member is unintentionally released, such as the restraining member being broken by a local force caused by the corner of the connecting member hitting the restraining member.

[0013] In the connecting and separating device, the releasing member may be a dividing member that divides a predetermined circumferential position of the restraining member, and the restraining member may have a deformation facilitating portion that is relatively easy to change in shape at a circumferential position different from the predetermined circumferential position. According to this aspect, when the restraining member is released by dividing a predetermined circumferential position of the restraining member by the dividing member that is the releasing member, the deformation facilitating portion provided at a circumferential position different from the dividing portion (predetermined circumferential position) changes in shape, and the restraining member can be made more likely to change in shape in the direction in which the dividing portion of the restraining member expands around this deformation facilitating portion. According to this, when the three or more connecting members move radially outward during restraint release, it becomes difficult for the restraining member to interfere with the movement, and higher separability can be realized.

[0014] In the connecting and separating device, the deformation facilitating portion may be constituted by a flexible portion having relatively high flexibility. According to this aspect, a deformable part can be easily provided in the restraining member.

[0015] Another aspect of the present invention is a method of assembling a connection and separation device among the above-described connection and separation devices, in which a biasing member biases at least one of the three or more connection members from the radially inner side to the radially outer side, and thereby biases the restraining member via the connection member. This assembly method includes arranging the biasing member radially inward of the three or more connection members, arranging the three or more connection members around the flange portion of the shaft member, inserting a rod-shaped jig through a through hole provided in the at least one connection member biased radially outward by the biasing member, attaching a tightening jig to the rod-shaped jig, and displacing the tightening jig in a direction against the biasing force of the biasing member, thereby moving the at least one connection member radially inward to a predetermined attachment position. After attaching the restraining member to the three or more connection members that have moved to the predetermined attachment position, the rod-shaped jig and the tightening jig are removed. According to this aspect, even if the biasing force of the biasing member arranged radially inward of the three or more connection members is strong (for example, so strong that it is difficult for an operator to move the connection member radially inward to a predetermined attachment position), by using the above-described rod-shaped jig and tightening jig, the connection member can be moved to the predetermined attachment position and restrained by the restraining member. Therefore, even if a biasing member with a strong biasing force is employed, the connection and separation device can be assembled in a connected state.

Advantages of the Invention

[0016] According to the present invention, it is possible to achieve both the connection force (maximum holding axial force) between the first structure and the second structure and the separability between the first structure and the second structure.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the connection and separation device according to the present invention will be described. The connection and separation device of the present embodiment is an example of a connection and separation device that can separably connect a launch rocket and a spacecraft or two spacecrafts. However, the connection and separation device according to the present invention is widely applicable as a device that can separably connect between structural bodies of any device as long as it can separably connect a first structural body and a second structural body.

[0019] FIG. 1 is a plan view showing the connecting and separating device of the present embodiment. FIG. 2 is a side view showing the connecting and separating device of the present embodiment. FIG. 3 is a perspective view showing the connecting and separating device of the present embodiment. FIG. 3 is a perspective view showing the connecting and separating device of the present embodiment. FIG. 4 is an explanatory view of the connecting and separating device of the present embodiment viewed from the axial direction. FIG. 5 is an exploded perspective view of the connecting and separating device of the present embodiment.

[0020] The connecting and separating device 1 of the present embodiment includes a first rod 2, a second rod 3, four separation nuts 4A to 4D, a restraint band 5, a nichrome wire 6, and a compression spring 7.

[0021] The first rod 2 is a shaft member provided on the first structure side. The second rod 3 is a shaft member provided on the second structure side. The first rod 2 and the second rod 3 have the same structure in the present embodiment, and as shown in FIG. 5, they each include attachment portions 2a, 3a, connecting portions 2b, 3b, and flange portions 2c, 3c. Note that, as the material of the first rod 2 and the second rod 3, for example, metal is preferably used, but it is appropriately selected according to its use (required strength, resistance, etc.).

[0022] The attachment portion 2a of the first rod 2 is a shaft portion (threaded portion) formed with a thread for attachment to the screw hole on the first structure side. The attachment portion 3a of the second rod 3 is a shaft portion (threaded portion) formed with a thread for attachment to the screw hole on the second structure side. In the present embodiment, the attachment portions 2a, 3a attached to the first structure and the second structure are constituted by threaded portions formed with threads, but the attachment portions 2a, 3a may have a structure other than the threaded structure according to the respective attachment structures of the first structure and the second structure.

[0023] The connecting parts 2b and 3b are shaft parts surrounded by separation nuts 4A to 4D. The connecting parts 2b and 3b of the present embodiment have a square cross-section perpendicular to the axial direction, and the surfaces facing the inner wall surfaces of the four separation nuts 4A to 4D are formed as flat surfaces. Since the inner wall surfaces of the four separation nuts 4A to 4D are formed as flat surfaces as will be described later, in the connected state, as shown in FIG. 4, the inner wall surfaces of the four separation nuts 4A to 4D and the connecting parts 2b and 3b of the respective rods 2 and 3 are in surface contact. With this configuration, the contact area between each of the rods 2 and 3 and the separation nuts 4A to 4D is ensured, the integrity during connection is improved, and a stronger connection can be easily realized.

[0024] The flange parts 2c and 3c are provided at one end side (the end part on the connecting part 2b and 3b side) of the first rod 2 and the second rod 3, respectively. Each flange part 2c and 3c is composed of four flanges extending in a right angle direction (radial direction perpendicular to the axial direction) from each of the four outer flat surfaces of the connecting part 2b and 3b having a square cross-section. In the present embodiment, each flange part 2c and 3c is composed of four independent (separated) flanges, but it may be composed of one flange connecting the four flanges.

[0025] Also, in the present embodiment, as shown in FIGS. 4 and 5, the four flanges constituting each flange part 2c and 3c have a rectangular shape when viewed from the axial direction. That is, the flange parts 2c and 3c of the present embodiment have a linear shape at the radially outer end when viewed from the axial direction.

[0026] The separation nuts 4A to 4D are connecting members arranged around the flange parts 2c and 3c of the first rod 2 and the second rod 3, and in the present embodiment, they are composed of four-segmented separation nuts. The four separation nuts 4A to 4D in the present embodiment are arranged so as to surround the entire circumference of the flange parts 2c and 3c, but they may be arranged only at a part of the circumferential direction of the flange parts 2c and 3c.

[0027] The separation nuts 4A to 4D of the present embodiment are produced, for example, by dividing a columnar member having a hollow portion with a cross-sectional shape substantially the same as the square cross-sectional shape of the connecting portions 2b and 3b of the respective rods 2 and 3 into four parts in the circumferential direction. The four separation nuts 4A to 4D in the present embodiment are configured to be divided into four equal parts in the circumferential direction, and their shapes are substantially the same, but the present invention is not limited to this, and they may have a configuration divided unevenly in the circumferential direction. As the material of the separation nuts 4A to 4D, for example, metal is preferably used, but it is appropriately selected according to its use (required strength, resistance, etc.).

[0028] The outer shape of the separation nuts 4A to 4D of the present embodiment takes a substantially cylindrical shape in the connected state. Therefore, it is possible to prevent the corners of the separation nuts 4A to 4D from hitting the restraint band 5 attached to the outer periphery of the separation nuts 4A to 4D. Thereby, it is possible to suppress a problem in which a local force acts on the restraint band 5 from the separation nuts 4A to 4D and the restraint of the restraint band 4 is unintentionally released.

[0029] On the inner wall side of the separation nuts 4A to 4D, there are provided restricting portions that restrict the first rod 2 (first structure) and the second rod 3 (second structure) from moving away from each other along the axial direction by coming into contact with the respective flange portions 2c and 3c. Specifically, on the inner wall side of the separation nuts 4A to 4D, as shown in FIG. 5, in the contacting state, two contact surfaces 4a, 4a that contact the outer wall surface (plane) of the connecting portions 2b, 3b of the respective rods 2, 3, and a recess 4b in which the respective flange portions 2c, 3c are inserted are formed between the two contact surfaces 4a, 4a.

[0030] In this configuration, in the connected state, the inner wall surfaces 4b1 and 4b2 in the axial direction of the concave portion 4b face the outer side surfaces 2c1 and 3c1 in the axial direction of the respective flange portions 2c and 3c from the outer side in the axial direction. Therefore, the inner wall surfaces 4b1 and 4b2 in the axial direction of the concave portion 4b of the separation nuts 4A to 4D function as the regulating portions, and the outer side surfaces 2c1 and 3c1 in the axial direction of the respective flange portions 2c and 3c are caught, thereby regulating the first rod 2 and the second rod 3 from moving in a direction away from each other along the axial direction.

[0031] The restraint band 5 is a restraint member that restrains the four separation nuts 4A to 4D from moving in the radial direction in the connected state. The restraint band 5 of the present embodiment is a non-stretchable pipe-shaped member, and as shown in FIGS. 1 to 3, it is mounted on the outer periphery of the four separation nuts 4A to 4D in the connected state. As the material of the restraint band 5, for example, resin (such as polycarbonate) is preferably used, but it is appropriately selected according to its use (required strength, resistance, etc.).

[0032] The nichrome wire 6 is a release member that releases the restraint of the restraint band 5 when the restraint is released. Specifically, the release member of the present embodiment connects the control unit 10 to the nichrome wire 6, and when the restraint is released, a current is passed from the control unit 10 to the nichrome wire 6 to heat the nichrome wire 6, and it is a splitting member that cuts and splits the restraint band 5 with heat. The nichrome wire 6 is wound around a recessed portion 5a provided in a part of the circumferential direction of the restraint band 5.

[0033] The restraint band 5 is mounted on the outer periphery of the four separation nuts 4A to 4D in the connected state so that the portion around which the nichrome wire 6 is wound is located at the upper part. A groove portion 4c extending in the axial direction is formed on the outer wall surface of the separation nut 4A located at the upper part among the four separation nuts 4A to 4D. Thereby, when the restraint band 5 is mounted, the nichrome wire 6 wound around the restraint band 5 is located inside the groove portion 4c of the separation nut 4A and is configured not to contact the separation nut 4A.

[0034] In the present embodiment, both inner wall surfaces 4b1 and 4b2 in the axial direction of the concave portions 4b of the separation nuts 4A to 4D include inclined surfaces that incline inward in the axial direction as they go outward in the radial direction. Therefore, when an external force that causes the first rod 2 and the second rod 3 to move away from each other in the axial direction is applied, a force that causes the outer axial surfaces 2c1 and 3c1 of the flange portions 2c and 3c of the respective rods 2 and 3 to move relative to the inclination of both inner wall surfaces 4b1 and 4b2 in the axial direction of the concave portions 4b of the separation nuts 4A to 4D acts. Due to this force, a force that causes the separation nuts 4A to 4D to move outward in the radial direction acts on the separation nuts 4A to 4D.

[0035] In the connected state, when an external force that causes the first rod 2 and the second rod 3 to move away from each other in the axial direction is applied, due to the restraining force of the restraining band 5, the separation nuts 4A to 4D cannot move outward in the radial direction. Therefore, the outer axial surfaces 2c1 and 3c1 of the flange portions 2c and 3c of the respective rods 2 and 3 cannot move along the inclination of both inner wall surfaces 4b1 and 4b2 in the axial direction of the concave portions 4b of the separation nuts 4A to 4D. Thus, even when an external force that causes the first rod 2 and the second rod 3 to move away from each other in the axial direction is applied, the outer axial surfaces 2c1 and 3c1 of the flange portions 2c and 3c are caught by both inner wall surfaces 4b1 and 4b2 in the axial direction of the concave portions 4b of the separation nuts 4A to 4D. As a result, the first rod 2 and the second rod 3 are restricted from moving away from each other in the axial direction, and the connected state is maintained.

[0036] FIG. 6 is an explanatory view of the connection and separation device in the separated state as viewed from the axial direction. FIG. 7 is a perspective view showing the connection and separation device in the separated state. When the current from the control unit 10 flows through the nichrome wire 6 and cuts the restraint band 5 by heat, the recessed portion 5a of the restraint band 5 around which the nichrome wire 6 is wound is divided in the circumferential direction. As a result, the restraint of the restraint band 5 that restrains the outward movement of the separation nuts 4A to 4D in the radial direction is released, and the separation nuts 4A to 4D are in a state where they can move outward in the radial direction. Thereby, an external force that causes the first rod 2 and the second rod 3 to move away from each other along the axial direction is applied, and a force that causes the outer axial surfaces 2c1 and 3c1 of the flange portions 2c and 3c of the respective rods 2 and 3 to relatively move along the inclination of the inner wall surfaces 4b1 and 4b2 in the axial direction of the recesses 4b of the separation nuts 4A to 4D acts, and the separation nuts 4A to 4D move outward in the radial direction.

[0037] And when the separation nuts 4A to 4D move outward in the radial direction until the radially inner ends of the inner wall surfaces 4b1 and 4b2 in the axial direction exceed the radially outer ends of the flange portions 2c and 3c, the first rod 2 and the second rod 3 can move away from each other along the axial direction. As a result, the first structure provided with the first rod 2 and the second structure provided with the second rod 3 are in a separated state.

[0038] Here, depending on the material and structure of the restraint band 5, just cutting the restraint band 5 with the nichrome wire 6 may maintain the shape of the restraint band 5, the inner ring of the restraint band 5 may not expand, and a restraining force that restrains the outward movement of the separation nuts 4A to 4D in the radial direction may remain slightly. Therefore, when the outward movement force acting on the separation nuts 4A to 4D is weak, the separation nuts 4A to 4D may be inhibited by the restraint band 5 in which the restraining force remains and may not be able to move outward in the radial direction until the radially inner ends of the inner wall surfaces 4b1 and 4b2 in the axial direction exceed the radially outer ends of the flange portions 2c and 3c.

[0039] Therefore, the connecting and separating device 1 of the present embodiment is provided with a compression spring 7 as a biasing member that biases the restraint band 5 from the radially inner side to the radially outer side. In the connected state, as shown in FIGS. 5 to 7, this compression spring 7 is disposed in a compressed state between the inner walls of the separation nuts 4B and 4D that are disposed on the side portions among the four separation nuts 4A to 4D. Therefore, the compression spring 7 applies a biasing force in the direction of separating from each other (radially outward) to the two separation nuts 4B and 4D. As a result, the restraint band 5 attached to the outer periphery of the separation nuts 4A to 4D receives a biasing force in the radially outward direction via the two separation nuts 4B and 4D.

[0040] Since the compression spring 7 is provided, when the restraint band 5 is cut by the nichrome wire 6, the inner ring of the restraint band 5 is pushed and expanded radially outward via the two separation nuts 4B and 4D. As a result, even when an external force that causes the first rod 2 and the second rod 3 to move away from each other along the axial direction acts on the separation nuts 4A to 4D with a weak radially outward moving force, the separation nuts 4A to 4D can be moved radially outward until the radially inner ends of the axial inner wall surfaces 4b1 and 4b2 exceed the radially outer ends of the respective flange portions 2c and 3c without being hindered by the restraint band 5. Therefore, higher separability can be obtained.

[0041] In particular, in the present embodiment, the direction of the biasing force by the compression spring 7 is in the direction of expanding the cutting portion (splitting portion) of the restraint band 5 cut by the nichrome wire 6. According to this, the inner ring of the restraint band 5 can be greatly pushed and expanded by the biasing force of the compression spring 7, and it is possible to effectively suppress the restraint band 5 from hindering the separation nuts 4A to 4D from moving radially outward when the restraint is released.

[0042] Here, when assembling the connection and separation device 1, with the compression spring 7 compressed between the two separation nuts 4B and 4D, the four separation nuts 4A to 4D are arranged around the flange portions 2c and 3c of the first rod 2 and the second rod 3. Then, while maintaining this state, it is necessary to perform the operation of attaching the restraint band 5 to the outer circumferences of the four separation nuts 4A to 4D.

[0043] At this time, during the operation, there is a problem that the two separation nuts 4B and 4D are likely to come off due to the biasing force of the compression spring 7, and it is difficult to smoothly attach the restraint band 5 to the four separation nuts 4A to 4D. In particular, when the biasing force of the compression spring 7 is large (for example, when the biasing force is so large that it is difficult for an operator to maintain the compressed state), the above operation becomes more difficult.

[0044] FIG. 8 is an explanatory diagram for explaining the assembly method of the connection and separation device 1 in the present embodiment. In the present embodiment, through holes 4d, 4d are provided in each of the two separation nuts 4B and 4D biased by the compression spring 7, and the assembly bolts 21, which are rod-shaped jigs used for assembly, are passed through the through holes 4d, 4d.

[0045] During assembly, with the compression spring 7 arranged between the two separation nuts 4B and 4D, the assembly bolt 21 is inserted into the through hole 4d of the separation nut 4D, passed through the compression spring 7, and arranged so as to pass through the through hole 4d of the separation nut 4B. Then, the assembly nut 22, which is an assembly tightening jig, is screwed from the tip side of the assembly bolt 21.

[0046] By tightening the assembly nut 22 screwed onto the assembly bolt 21, two separation nuts 4B, 4D and the compression spring 7 can be sandwiched between the screw head 21a of the assembly bolt 21 and the assembly nut 22. Then, as the assembly nut 22 is tightened, the space between the two separation nuts 4B, 4D narrows against the biasing force of the compression spring 7. As a result, the two separation nuts 4B, 4D move radially inward to a predetermined mounting position (a position where the contact surfaces 4a, 4a of the two separation nuts 4B, 4D contact the outer wall surface (flat surface) of the connecting portions 2b, 3b of the respective rods 2, 3) against the biasing force of the compression spring 7.

[0047] After sandwiching the two separation nuts 4B, 4D and the compression spring 7 between the screw head 21a of the assembly bolt 21 and the assembly nut 22, the remaining two separation nuts 4A, 4C are also set at the predetermined mounting positions. Then, a restraint band 5 is temporarily attached to the outer peripheries of these four separation nuts 4A to 4D.

[0048] At this time, the temporary attachment position of the restraint band 5 is offset from the vicinity of the axial center of the separation nuts 4A to 4D toward one end side because the assembly bolt 21 is present near the axial center of the separation nuts 4A to 4D. At this position, the restraint by the restraint band 5 on the other end side of the separation nuts 4A to 4D tends to be insufficient.

[0049] In the present embodiment, after the restraint band 5 is attached (temporarily attached), the assembly nut 22 is loosened, and the assembly bolt 21 and the assembly nut 22 are removed. Then, the temporarily attached restraint band 5 is slid (slid) near the axial center of the separation nuts 4A to 4D. As a result, the restraint band 5 is attached near the axial center of the separation nuts 4A to 4D, and a sufficient restraining force by the restraint band 5 can be exerted on any end side of the separation nuts 4A to 4D.

[0050] In a connecting and separating device 1 such as the present embodiment, it is required that the connecting force between the first rod 2 (first structure) and the second rod 3 (second structure) in the connected state is large, and the separability between the first rod 2 (first structure) and the second rod 3 (second structure) at the time of restraint release is high (stable separation is possible).

[0051] Generally, the connecting force can be evaluated by the force (maximum holding axial force) that holds the first rod 2 (first structure) and the second rod 3 (second structure) so as not to move in the direction of separating from each other along the axial direction. Here, the "maximum holding axial force" means the axial force when the separation nuts 4A to 4D move in the radial direction due to an external force (axial force) that causes the first rod 2 (first structure) and the second rod 3 (second structure) to move in the direction of separating from each other along the axial direction, increasing the tension of the restraint band 5 and causing the restraint band 5 to break.

[0052] And usually, the wider the contact portions between the inner wall surfaces 4b1 and 4b2 in the axial direction of the concave portions 4b of the separation nuts 4A to 4D and the outer side surfaces 2c1 and 3c1 in the axial direction of the flange portions 2c and 3c of the respective rods 2 and 3 are, the greater the maximum holding axial force of the connecting and separating device 1 becomes. Therefore, the greater the height of the flange portions 2c and 3c of the respective rods 2 and 3 (the length of the flange portions 2c and 3c in the radial direction from the outer wall surface (plane) of the connecting portions 2b and 3b of the respective rods 2 and 3) and the greater the height of the inner wall surfaces 4b1 and 4b2 in the axial direction of the concave portions 4b of the separation nuts 4A to 4D (the depth of the concave portions 4b) are, the greater the maximum holding axial force becomes.

[0053] However, the greater these heights are, the longer the distance that the separation nuts 4A to 4D have to move radially outward to release the restraint of the restraint band 5 becomes. Therefore, when releasing the restraint of the restraint band 5, the separation nuts 4A to 4D are likely to get caught on the flange portions 2c and 3c of the respective rods 2 and 3, and the separability deteriorates.

[0054] Considering the above, in order to increase the maximum holding axial force of the connection and separation device 1 while suppressing the deterioration of the separability, it is effective to increase the circumferential width of the contact portion between the axially opposite inner wall surfaces 4b1 and 4b2 of the concave portions 4b of the separation nuts 4A to 4D and the flange portions 2c and 3c of the respective rods 2 and 3.

[0055] FIG. 9 is an explanatory view when an example of a conventional connection and separation device 1 is viewed from the axial direction. In many of the conventional connection and separation devices 1, as shown in FIG. 9, a shaft member 2' provided with a circular flange portion 2c' (the shape of the radially outer end of the flange portion 2c' when viewed from the axial direction is a curved shape (arc shape)) is used for the columnar shaft portion 2a'. Then, two separation nuts 4E' and 4F' that are each half a circumference are arranged around the flange portion 2c'. According to this, the regulating portions 4b' provided on the inner wall sides of the two separation nuts 4E' and 4F' come into contact with the entire circumference of the circular flange portion 2c'. Therefore, the circumferential width of the contact portion between the regulating portion 4b' of the separation nuts 4E' and 4F' and the flange portion 2c' of the shaft member 2' can be maximally increased, and it is possible to obtain a large maximum holding axial force.

[0056] However, in the example of FIG. 9, the shape of the radially inner end 4a' of the regulating portion 4b' when viewed from the axial direction is a curved shape (arc shape) following the side surface of the columnar shaft portion 2a', and during connection, the entire radially inner end region of the regulating portion 4b' contacts along the side surface of the shaft portion 2a'. In this configuration, the curved shape of the radially inner end of the regulating portion 4b' when viewed from the axial direction has a larger curvature than the curved shape of the radially outer end of the flange portion 2c'.

[0057] Therefore, when the separation nuts 4E' and 4F' move radially outward when the restraint is released, even if they move a distance L corresponding to the height of the flange portion 2c' of the shaft member 2' or the height of the restricting portion 4b' of the separation nuts 4E' and 4F', the entire radially inner end of the restricting portion 4b' still cannot move to the outside of the flange portion 2c'. Specifically, even if the separation nuts 4E' and 4F' move the distance L radially outward when the restraint is released, both circumferential ends (the four portions circled by a circle in FIG. 9) of the radially inner end of the restricting portion 4b' cannot move to the outside of the flange portion 2c'. Therefore, when the restraint is released, the situation where both circumferential ends of the radially inner end of the restricting portion 4b' are caught by the flange portion 2c' easily occurs, and the separability is poor.

[0058] On the other hand, as a method for improving the separability in the example of FIG. 9, for example, a configuration can be considered in which a portion of the flange portion 2c' (the portion shown by hatching in FIG. 9) where both circumferential ends of the radially inner end of the restricting portion 4b' are caught is removed. However, when a part of the flange portion 2c' is removed in this way, the circumferential width of the contact portion between the restricting portion 4b' of the separation nuts 4E' and 4F' and the flange portion 2c' of the shaft member 2' becomes narrow during connection, and there is a risk that the maximum holding axial force is insufficient.

[0059] In the connection and separation device 1 of the present embodiment, as described above, when viewed from the axial direction, the radially outer end shapes of the flange portions 2c and 3c of the respective rods 2 and 3 are linear shapes. Also, when viewed from the axial direction, the radially inner end shape of the restricting portion (the axially both inner wall surfaces 4b1 and 4b2 of the concave portion 4b) of the separation nuts 4A to 4D is a linear shape substantially parallel to the linear shape of the flange portions 2c and 3c. According to such a configuration, when the individual separation nuts 4A to 4D move a distance corresponding to the height of the flange portions 2c and 3c or the height of the restricting portion of the separation nuts 4A to 4D radially outward when the restraint is released, all of the radially inner ends of the restricting portion can move to the outside of the flange portions 2c and 3c. Therefore, high separability can be obtained.

[0060] In addition, in the connecting and separating device 1 of the present embodiment, the number of separation nuts 4A to 4D arranged around the flange portions 2c and 3c is four. According to this, in order to improve the separability in the example of FIG. 9, the portion of the flange portion 2c' (the portion indicated by the oblique lines in FIG. 9) where both circumferential end portions of the radially inner end of the restricting portion 4b' are caught as described above is removed. The circumferential width of the contact portion between the restricting portion of the separation nuts 4A to 4D and the flange portions 2c and 3c of the respective rods 2 and 3 can be made wider than in the case of the configuration. Therefore, it is possible to secure a high holding axial force.

[0061] Therefore, according to the present embodiment, it is possible to achieve both the connecting force (maximum holding axial force) of the first structure and the second structure and the separability of the first structure and the second structure.

[0062] Note that the connecting and separating device 1 of the present embodiment is configured such that four separation nuts 4A to 4D are arranged around the flange portions 2c and 3c provided on both the first rod 2 provided on the first structure side and the second rod 3 provided on the second structure side. However, the present invention is not limited to this configuration. For example, the second rod 3 may be omitted, and the separation nuts 4A to 4D may be directly provided on the second structure side.

[0063] [Modification Example 1] Next, a modification example of the restraint band 5 in the above-described embodiment (hereinafter, this modification example is referred to as "Modification Example 1") will be described. In the connecting and separating device 1 having the configuration of the above-described embodiment, there is a case where the actually measured value of the maximum holding axial force is lower than the designed value (theoretical value) (for example, the actually measured value is about 70% of the designed value). When examining the cause of this, it was found that the cause is that the mounting position of the restraint band 5 is displaced from the axial center position of the separation nuts 4A to 4D when an external force (axial force) that moves the first rod 2 and the second rod 3 away from each other along the axial direction is applied.

[0064] Specifically, if the mounting position of the restraint band 5 is biased toward one axial end side (e.g., the first rod 2 side) of the separation nuts 4A to 4D, the restraining force for preventing the other axial end side (e.g., the second rod 3 side) of the separation nuts 4A to 4D from moving radially is insufficient. As a result, as shown in FIG. 10, before the external force F that causes the first rod 2 and the second rod 3 to move away from each other along the axial direction reaches the maximum holding axial force of the design value, only the other axial end side of the separation nuts 4A to 4D is expanded radially, and the connection of the second rod 3 on the other end side is released.

[0065] FIG. 11 is a plan view showing the connection and separation device 1 in the first modification example. The first modification example uses a restraint band 15 with a wider band width than the restraint band 5 of the connection and separation device 1 in the above-described embodiment. For example, instead of the restraint band 5 of the above-described embodiment having a length (band width) of about 1 / 3 of the axial length of the separation nuts 4A to 4D, a restraint band 15 having a length (band width) of about 2 / 3 of the axial length of the separation nuts 4A to 4D is used. As a specific example, when the axial length of the separation nuts 4A to 4D is 32 mm, the band width of the restraint band 5 in the above-described embodiment is 10 mm, whereas the band width of the restraint band 5 in the first modification example is 20 mm.

[0066] According to the first modification example, by using the restraint band 15 having a long axial length (wide band width), even if the restraint band 5 is mounted slightly deviated toward one axial end side (e.g., the first rod 2 side) of the separation nuts 4A to 4D, it is possible to suppress the occurrence of a situation where the restraining force on the other end side (e.g., the second rod 3 side) is insufficient, and the maximum holding axial force can be improved. Therefore, when assembling the connection and separation device 1, the accuracy of the mounting position of the restraint band 5 is less likely to affect the maximum holding axial force, and the ease of assembly is improved.

[0067] 〔Second Modification Example〕 Next, another modification example of the restraint band 5 in the above-described embodiment (hereinafter, this modification example is referred to as “second modification example”) will be described. As described in the above embodiments, depending on the material and structure of the restraint band 5, etc., simply cutting the restraint band 5 with the nichrome wire 6 may maintain the shape of the restraint band 5, prevent the inner ring of the restraint band 5 from expanding, and residual restraint force that restrains the radial outward movement of the separation nuts 4A to 4D may remain. In this case, the separation nuts 4A to 4D may be unable to move radially outward until the radially inner ends of the axial inner wall surfaces 4b1 and 4b2 exceed the radially outer ends of the respective flange portions 2c and 3c due to being inhibited by the restraint band 5 with residual restraint force, and there is a possibility that high separability cannot be obtained.

[0068] In particular, when using a restraint band with a wide band width like the restraint band 15 of the above-described modification 1, simply cutting the restraint band 5 with the nichrome wire 6 may not sufficiently expand the inner ring of the restraint band 5, making it difficult to obtain high separability.

[0069] In addition, in the above-described embodiments, by providing the compression spring 7, when the restraint band 5 is cut with the nichrome wire 6, the inner ring of the restraint band 5 is pushed and expanded radially outward via the two separation nuts 4B and 4D by the biasing force of the compression spring 7 to ensure high separability. However, even when the compression spring 7 is provided, depending on the material and structure of the restraint band 5, etc. (for example, when using the restraint band 15 of the above-described modification 1), there is a possibility that high separability cannot be obtained. Moreover, when adopting a configuration without providing the compression spring 7, the possibility of not obtaining high separability is high.

[0070] Therefore, in this modification 2, when the portion of the recess 5a of the restraint band is cut with the nichrome wire 6, a deformation facilitating portion is provided on the restraint band to make it easier for the portion of the recess 5a of the restraint band to move away in the circumferential direction. This deformation facilitating portion can be constituted by, for example, a flexible portion (a portion having higher flexibility and being easier to deform than other portions) provided at a circumferential position of the restraint band different from the recess 5a cut by the nichrome wire 6.

[0071] As an example of such a deformable part (flexible part), for example, as shown in FIG. 12, at a location on the opposite side of the recessed part 5a around which the nichrome wire 6 is wound with respect to the restraint band 5 of the above-described embodiment (a location 180° in the circumferential direction of the restraint band 5), a recessed part 5b similar to the recessed part 5a is provided, and a through hole 5c is provided at that location. According to the restraint band 25A according to the example of FIG. 12, since the meat part area of the restraint band 25A at the location on the opposite side of the recessed part 5a around which the nichrome wire 6 is wound is reduced, the flexibility of the location on the opposite side of the recessed part 5a is relatively increased, and that location becomes a flexible part.

[0072] According to the example of FIG. 12, when the location of the recessed part 5a of the restraint band is cut by the nichrome wire 6 and the inner ring of the restraint band 5 is pushed radially outward via the two separation nuts 4B and 4D, only the location on the opposite side of the recessed part 5a can be easily deformed even if the parts other than the location on the opposite side of the recessed part 5a do not deform much. Therefore, the restraint band 25A can be easily deformed (bent back) so that the location of the recessed part 5a of the restraint band opens around the location on the opposite side of the recessed part 5a. As a result, high separability can be obtained.

[0073] Also, as another example of the deformable part, for example, as shown in FIG. 13, with respect to the restraint band 5 of the above-described embodiment, at the location on the opposite side of the recessed part 5a around which the nichrome wire 6 is wound, a configuration in which only the through hole 5c is provided without providing the recessed part 5b can be cited. Also in the restraint band 25B according to the example of FIG. 13, since the meat part area of the restraint band 25B at the location on the opposite side of the recessed part 5a around which the nichrome wire 6 is wound is reduced, the location on the opposite side of the recessed part 5a becomes a flexible part. Therefore, similar to the example of FIG. 12, high separability can be obtained.

[0074] However, compared with the example of FIG. 12, since the flexibility is reduced by the amount of the recessed part 5b not being provided, when compensating for the reduction in the flexibility, as shown in the example of FIG. 13, the size of the through hole 5c may be made larger than that in the example of FIG. 12.

[0075] In particular, in the case of the restraint band 25B in the example of FIG. 13, the shape of the through-hole 5c is a horizontally long circle that is long in the circumferential direction of the restraint band 25B. With such a shape, it is considered that stress concentration is less likely to occur when a tensile load is applied in the direction of increasing the diameter of the restraint band 25B. Also, generally, the amount of deflection of the free end of a member increases as the length from the fixed end to the free end of the member increases. Therefore, in the restraint band 25B in which a band material that is originally close to a planar state is deflected into an annular state, when forming the through-hole 5c having a circumferential length L, the larger the circumferential length L of the through-hole 5c, the more likely the circumferential portion of the restraint band 25B in which the through-hole 5c is formed is to warp. That is, when the recessed portion 5a of the restraint band is cut by the nichrome wire 6, the restraint band 25A easily changes its shape so that the recessed portion 5a of the restraint band opens. Therefore, by forming the through-hole 5c having a horizontally long circle with a relatively long circumferential length L as in the restraint band 25B in the example of FIG. 13, high separability can be obtained.

[0076] Further, as still another example of the easily deformable portion, for example, as shown in FIG. 14, a configuration in which a thin portion 5d with a reduced thickness is provided at a location on the restraint band 5 of the above-described embodiment opposite to the location where the nichrome wire 6 is wound can be cited. In the restraint band 25C according to the example of FIG. 14, the location on the opposite side (thin portion 5d) to the location where the nichrome wire 6 is wound has a relatively increased flexibility because the thickness of the restraint band 25C is thin, and that location becomes a flexible portion. Therefore, similar to the examples of FIGS. 12 and 13, high separability can be obtained.

[0077] Note that in the example of FIG. 14, the location where the nichrome wire 6 is wound is a thin portion 5a' similar to the thin portion 5d provided at a location on the opposite side to the recessed portion 5a, rather than the recessed portion 5a. According to this, the restraint band 25C can be made into an axially symmetric shape, so that the operation of aligning the circumferential position of the restraint band 25C with the separation nuts 4A to 4D during assembly becomes easy.

Description of Reference Numerals

[0078] 1: Connecting and Separating Device 2: First rod 2a: Mounting part 2b: Connecting part 2c: Flange part 2c1: Axial outer surface 2': Shaft member 2a': Shaft part 2c': Flange part 3: Second rod 3a: Mounting part 3b: Connecting part 3c: Flange part 3c1: Axial outer surface 4A~4D, 4E', 4F': Separation nut 4a: Contact surface 4b: Recess 4b1, 4b2: Both inner wall surfaces in the axial direction 4c: Groove part 4d: Through hole 4a': Radial inner end 4b': Regulation part 5, 15, 25A, 25B, 25C: Restraint band 5a: Depression 5a': Thin part 5b: Depression 5c: Through hole 5d: Thin part 6: Nichrome wire 7: Compression spring 10: Control part 21: Assembly bolt 21a: Screw head 22: Assembly nut

Claims

1. A connection / separation device that separably connects a first structure and a second structure, A shaft member provided on the first structure side; Three or more connecting members provided on the second structure side and arranged around the flange portion of the shaft member; A restraining member that restrains the three or more connecting members from moving in a radial direction perpendicular to the axial direction; A release member that releases the restraint of the restraining member, a restricting portion is provided on an inner wall side of the three or more connecting members, the restricting portion restricting movement of the first structure and the second structure in a direction away from each other along the axial direction by contacting the flange portion, The shape of the radially outer end of the flange portion when viewed from the axial direction is a straight line, A coupling and decoupling device, wherein a shape of a radially inner end of the restricting portion when viewed from an axial direction is a straight line shape substantially parallel to the straight line shape of the flange portion.

2. The coupling / separation device according to claim 1 , A coupling / disconnecting device comprising a biasing member for biasing the restraining member radially outward from a radially inward side.

3. The coupling / separation device according to claim 2, A connection and separation device characterized in that the biasing member biases at least one of the three or more connecting members from the radially inward side to the radially outward side, thereby biasing the restraining member via the connecting member.

4. The coupling / separation device according to claim 2 or 3, the release member is a divided member that divides a predetermined circumferential position of the restraint member, A connection and separation device, wherein the biasing member biases the restraining member in a direction in which a separation portion of the restraining member widens.

5. The coupling / decoupling device according to any one of claims 1 to 3, A second shaft member is provided on the second structure side, the three or more connecting members are disposed around both the flange portion of the shaft member and the second flange portion of the second shaft member, a second regulating portion configured to abut against the second flange portion on an inner wall side of the three or more connecting members and to regulate the first structure and the second structure from moving in a direction away from each other along the axial direction, The shape of the radially outer end of the second flange portion when viewed from the axial direction is a straight line, A connection and separation device, characterized in that the shape of the radially inner end of the second regulating portion when viewed from the axial direction is a straight line shape that is approximately parallel to the straight line shape of the flange portion.

6. The coupling / decoupling device according to any one of claims 1 to 3, A connection and separation device, characterized in that the side surface of the shaft portion surrounded by the three or more connection members is formed as a flat surface facing each of the connection members.

7. The coupling / decoupling device according to any one of claims 1 to 3, A connection and separation device, characterized in that when the three or more connection members are arranged around the flange portion of the shaft member, the outer shape thereof is cylindrical.

8. The coupling / decoupling device according to any one of claims 1 to 3, the release member is a divided member that divides a predetermined circumferential position of the restraint member, A connection and separation device, wherein the restraint member has an easily deformable portion, the easily deformable portion being at a circumferential position different from the predetermined circumferential position, the easily deformable portion being relatively more likely to deform in shape.

9. The coupling / separation device according to claim 8, A connection and separation device, wherein the easily deformable portion is composed of a flexible portion having relatively high flexibility.

10. 4. The method for assembling a coupling / separation device according to claim 3, further comprising the steps of: The three or more connecting members are arranged around the flange portion of the shaft member in a state where the biasing member is arranged radially inward of the three or more connecting members, A rod-shaped jig is inserted into a through hole provided in the at least one connecting member that is biased radially outward by the biasing member; a clamping jig is attached to the rod-shaped jig and the clamping jig is displaced in a direction against the biasing force of the biasing member, thereby moving the at least one connecting member radially inward to a predetermined mounting position; After the restraining member is attached to the three or more connecting members that have been moved to the predetermined attachment position, removing the rod-shaped jig and the tightening jig.

Images