JP6038696B2 - Bolt device and expansion joint - Google Patents

Description

  The present invention relates to a slidably movable bolt device spanned between a first portion and a second portion facing each other, and an expansion joint including the bolt device as a stopper.

  A bolt device having a bolt and a nut is usually used to fasten objects, and is used so as to function alternatively between a fastening state and a releasing state.

  In the expansion joint that connects the first pipe and the second pipe so as to accept the expansion and contraction, the distance between the first pipe as the first part and the second pipe as the second part is an external force. May grow in response. On the other hand, a stopper is used to limit the extension between the first pipe and the second pipe in order to prevent the first pipe and the second pipe from being detached from the expansion joint.

There are various types of stoppers, and those using bolts and nuts are known.
JP 2004-116708 A

  Conventional bolt devices composed of bolts and nuts have limited applications because they only function alternatively between the state of fastening and the state of releasing the fastening. It was.

  Moreover, in the expansion joint provided with the conventional bolt apparatus as a stopper of an expansion joint, the stopper itself was not able to extend according to the expansion between piping.

  Accordingly, an object of the present invention is to solve the above-described problems of the prior art, and to provide a slidably movable bolt device that spans between the first portion and the second portion facing each other, and a simple provision of this bolt device as a stopper. It is to provide an expansion joint that allows an increase in the interval between pipes in a structure.

  In order to achieve the above object, a bolt device according to the present invention is a bolt device spanned between a first portion and a second portion facing each other, wherein the head and the head are in contact with the first portion. A bolt having a shaft portion directed from the portion toward the second portion and a plurality of divided divided units can be combined and screwed to the shaft portion, and a surface toward the second portion in a cross-sectional view A cracking nut having a pressure-receiving inclined surface inclined with respect to the axis, an elastic member disposed on an outer peripheral portion of the shaft portion and elastically deformable in an axial direction, and pre-compressing the elastic member to A preload applying member for applying a compressive force; and a contact inclined surface that abuts the cracked nut receiving the precompressive force on the opposite side of the elastic member with respect to the axis in contact with the pressure receiving inclined surface in a cross-sectional view. Contact member and the contact member in front A connecting member connected to the second part, and when an external force acts in the axial direction in the direction of expanding the distance between the first part and the second part, and the external force is greater than or equal to a predetermined value. In addition, the split nut expands in diameter as the screwed state between the split nut and the bolt is released, and the bolt slides relative to the split nut.

  In addition, the elastic member is a disc spring set including a plurality of disc springs arranged in the axial direction.

  The pre-compression force is given by compressing the disc spring set, and the predetermined value is set as a state in which the disc spring set is further compressed.

  In addition, the preload adding member has a push screw that can be screwed into a housing that houses the elastic member, and the precompression force is set by a degree to which the push screw is screwed into the housing. To do.

  Further, the pressure-receiving inclined surface has an acute predetermined angle with respect to the first part side.

  The predetermined angle is an angle in a range of 45 degrees to 75 degrees.

  Further, the crack nut has a small diameter portion and a large diameter portion.

  The expansion joint according to the present invention is an expansion joint for connecting the first pipe and the second pipe so that the first pipe and the second pipe do not separate beyond a predetermined length in the axial direction. A stopper for limiting, the stopper includes a first part provided on an outer peripheral part of the first pipe, a second part provided on an outer peripheral part of the second pipe, the first part, and the And a bolt device spanned between the second part, wherein the bolt device is as defined in claim 1.

  According to the configuration of the bolt device of the present invention, when the external force is smaller than the predetermined value, the distance between the first part and the second part is maintained in a steady state, and when the external force is greater than the predetermined value, the bolt is cracked. When the external force becomes smaller than a predetermined value while sliding with respect to the nut, the bolt is fitted to the cracked nut to stop the sliding movement, so that the distance between the first part and the second part is extended by the amount of sliding movement. be able to.

  Moreover, since the stopper of an expansion joint is equipped with said bolt apparatus, when an external force more than predetermined value is received by the influence of an earthquake etc., an expansion joint does not remove | deviate from a 1st site | part and a 2nd site | part. And the second portion can be automatically extended until the external force becomes smaller than a predetermined value.

The figure which shows the state in which the steady tension load was added in the volt | bolt apparatus which concerns on one Embodiment of this invention. In the bolt device concerning one embodiment of the present invention, a figure showing the state where a big load was added in addition to regular tension load, and external force became more than a predetermined value. The perspective view which shows a crack nut. The figure which shows the end surface of a crack nut. The figure which shows a disc spring set. The figure which shows one Embodiment of the expansion joint of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are views showing an embodiment of a bolt device according to the present invention.

The bolt device 1 is used by being stretched between a first portion 51 and a second portion 52 which face each other.
The bolt device 1 includes a bolt 4 having a head 3 that abuts on a first part 51 and a shaft 2 that faces the second part 52 from the head 3 and a plurality of divided units 5 that are combined to form a shaft. A crack nut 8 having a pressure-receiving inclined surface 7 that can be screwed to the portion 2 and that faces the second portion 52 in a cross-sectional view is inclined with respect to the axis 6, and is disposed on the outer peripheral portion of the shaft portion 2. A disc spring set 9 as an elastic member that can be elastically deformed, a preload application member 10 for precompressing the disc spring set 9 to add a precompression force F1 to the crack nut 8, and a precompression force F1. An abutting member 12 having an abutting inclined surface 11 that abuts against the pressure-receiving inclined surface 7 in a cross-sectional view on the opposite side of the disc spring assembly 9 with respect to the axis 6, and the abutting member 12 as a second portion 52. And a connecting member 13 to be connected.

  When the external force F acts on the first part 51 with respect to the second part 52 in the direction in which the distance between the first part 51 and the second part 52 is increased, and the external force F is greater than or equal to a predetermined value F2. As will be described below, the crack nut 8 increases in diameter so that the screwed state between the crack nut 8 and the bolt 4 is released, and the bolt 4 slides relative to the crack nut.

  As shown in FIGS. 1 and 2, the head 3 of the bolt 4 is attached to the shaft 2 so that the shaft 2 is attached to the first portion 51. The head 3 may be configured integrally with the shaft 2 from the beginning, or the head 3 is formed as a separate body from the shaft 2 and is later screwed onto the shaft 2 and attached. Also good.

  As shown in FIG. 4, the crack nut 8 is configured by combining a plurality of, for example, four divided units 5, and when the diameter is increased, a gap g is formed between adjacent divided units 5. The size of the gap g corresponds to the difference in the size of the divided unit 5 before and after the diameter expansion. As the degree of diameter expansion of the split unit 5 increases, the portion of the crack nut 8 that engages with the male screw 18b of the shaft portion 2 of the female screw 18a of the crack nut 8 becomes smaller, and finally the shaft portion of the female screw 18a of the crack nut 8 The portion to be screwed into the second male screw 18b disappears, and the screwing relationship between the crack nut 8 and the shaft member 12 is released. When the screwing relationship between the crack nut 8 and the shaft member 12 is released, the bolt 4 slides relative to the crack nut 8. When the bolt 4 slides relative to the crack nut 8, the crack nut 8 no longer acts on the crack nut 8 from the male screw 18b of the shaft member 12, so the crack nut 8 expands beyond the diameter when the screwing relationship is released. Not diameter. Further, when the external force F becomes smaller than the predetermined value F2, the screwing relationship between the crack nut 8 and the shaft member 12 is restored, the sliding movement is stopped, and the first part 51 and the second part 52 move integrally. It becomes a relationship.

  The crack nut 8 is composed of a small diameter portion 8a at the front end and a large diameter portion 8b at the rear end. The small diameter portion 8a is composed of a pressure receiving inclined surface 7a at the front end and a cylindrical portion subsequent thereto, and the large diameter portion 8b is a pressure receiving inclined surface at the front end. 7b followed by a cylindrical portion.

  A ring-shaped gap 19a is formed between the peripheral surface of the cylindrical portion of the small-diameter portion 8a of the cracking nut 8 and the inner peripheral surface of the tip protrusion of the contact member 12, and the large-diameter portion 8b of the cracking nut 8 is formed. A ring-shaped gap 19 b is formed between the peripheral surface of the cylindrical portion and the inner peripheral surface of the second nut portion 17. A gap region 19 is formed by the gap 19a and the gap 19b. The size of the gap region 19 in FIG. 1 in the radial direction is formed to be equal to or larger than the amount of increased radius that the crack nut 8 expands and increases.

  The pressure-receiving inclined surface 7a and the pressure-receiving inclined surface 7b have the shape of a circular truncated cone, and the pressure-receiving inclined surface 7a and the pressure-receiving inclined surface 7b form an acute predetermined angle θ with respect to the first portion 51 side in a sectional view. The predetermined angle θ is, for example, an angle in the range of 45 degrees to 75 degrees. According to experiments, when the predetermined angle θ is an angle between 45 degrees and 75 degrees, the pressure receiving inclined surface 7a and the pressure receiving inclined surface 7b are effectively pressed by the contact surface 11a and the contact surface 11b. Can be transmitted.

  The reason why the crack nut 8 is formed by the small diameter portion 8a at the tip and the large diameter portion 8b at the rear end is to reduce the effective size of the crack nut 8 in the radial direction. That is, in order for the cracking nut 8 and the bolt 4 to be fitted with a required strength or more, the cracking nut 8 needs to be able to be fitted with the male screw of the bolt 4 to have a predetermined strength or more. It requires more than a predetermined length in the axial direction. In this case, if the pressure receiving inclined surface 7a of the small diameter portion 8a and the pressure receiving inclined surface 7b of the large diameter portion 8b are formed by a single pressure receiving inclined surface, the effective size of the crack nut 8 in the radial direction increases. It is necessary to avoid this.

  The preload adding member 10 is disposed between the outer peripheral surface of the shaft portion 2 and the inner surface of the cylindrical disc spring housing 15. The first nut portion 16 is attached to the first portion 51 side of the disc spring housing 15, and the second nut portion 17 is attached to the second portion 52 side of the disc spring housing 15.

  The preload adding member 10 is formed as a push screw, for example, and is disposed so as to be screwed to the first nut portion 16 from the first portion 51 side. The preload applying member 10 applies a precompression force F1 in a direction to reduce the length of the disc spring set 9 via the ring-shaped member 10a and the member 10b. The magnitude of the force applied to the disc spring assembly 9 can be adjusted according to the depth at which the preload applying member 10 is screwed into the first nut portion 16, and can be set to a predetermined precompression force F1. As shown in FIG. 1, a force F1 is applied to the seating surface of the nut 3 from the first portion 51 side as a reaction force of the precompression force F1. Here, the purpose of applying a precompression force to the cracking nut 8 is to ensure that the diameter expansion response of the cracking nut 8 to the external force is sensitive to the magnitude of the external force. That is, the play with respect to the external force with respect to the diameter expansion of the crack nut 8 is removed, and when a larger external force is applied to the bolt device 1 from the state shown in FIG. This is so that the diameter can be increased. In addition, setting the precompression force F1 to the preload application member 10 and the crack nut 8 by the preload application member 10 may be performed at the site where the first part 51 and the second part 52 are assumed, or the bolt device 1. It may be performed in advance at the factory where the products are shipped.

  The precompression force F <b> 1 is generated using the preload adding member 10 and the disc spring set 9. The disc spring set 9 has a mechanically high-accuracy load characteristic in relation to the amount of reduction and the generated compression force. Thereby, the magnitude of the precompression force F1 applied to the disc spring assembly 9 can be set by adjusting the degree of the precompression force F1 screwed into and into the first nut portion 16, so that it is extremely high. The size can be set with accuracy. This means that the predetermined value F2 is accurately set even with respect to the predetermined value F2. When the magnitude of the external force F reaches the predetermined value F2, the bolt 4 is surely slipped and moved with respect to the cracking nut 8. Will do.

  The contact member 12 is disposed so as to be screwed to the second nut portion 17 from the second portion 52 side. At the tip of the contact member 12, a contact surface 11a that contacts the pressure receiving inclined surface 7a of the crack nut 8 and a contact surface 11b that contacts the pressure receiving inclined surface 7b are formed. In the cross-sectional view, the pressure receiving inclined surface 7a and the pressure receiving inclined surface 7b correspond to an acute predetermined angle with respect to the first portion 51 side, and the contact surface 11a and the pressure receiving inclined surface 7b are in contact with the pressure receiving inclined surface 7a. The abutting contact surface 11b has an obtuse angle with respect to the first portion 51 side, that is, an angle obtained by subtracting the predetermined angle θ from 180 degrees.

  From the first part 51 side toward the second part 52 side, a preload application member 10, a member 10a, a disc spring set 9, a member 10b, a cracking nut 8, and a contact member 12 are disposed.

  Since the pressure-receiving inclined surface 7a and the pressure-receiving inclined surface 7b form an acute predetermined angle with respect to the first portion 51 side, the pre-load applying member 10 pre-compresses the disc spring assembly 9 and pre-compresses force F1 against the crack nut 8. When each of the split units 5 of the crack nut 8 is to be added, it is pressed toward the central axis. When the precompression force F1 is applied, the size of the gap g is zero. When the external force exceeds the precompression force F1, the size of the gap g gradually increases from zero. The magnitude of the precompression force F1 is set so that the magnitude of the gap g increases sensitively from zero when the external force F exceeds the precompression force F1.

  The connection member 13 that connects the contact member 12 to the second portion 52 includes a connection housing 23 attached to the contact member 12, a connection bolt 24 attached to the connection housing 23, and a shaft portion of the connection bolt 24. A connecting nut 25 for attaching the connecting member 13 to the second portion 52 is provided. In the connection housing 23 and the abutting member 12, a portion of the shaft portion 2 that is located closer to the second portion 52 than the crack nut 8 is accommodated.

  Next, the disc spring set 9 as an elastic member will be described. The disc spring set 9 is formed in a ring shape so that the shaft portion 2 penetrates. FIG. 5 shows an outer portion of the shaft portion 2 as an example of the disc spring set 9. The disc spring assembly 9 shown in FIG. 5 is configured by six disc spring sets each including six disc spring units, that is, a total of 60 disc spring units arranged in series. One disc spring unit has an outer diameter of about 30 mm, an inner diameter of about 16 mm, a thickness of about 2 mm, a total deflection amount of about 1 mm, and a load characteristic when the deflection amount is about 0.3 mm. 300 kgf.

  The pre-compression force F1 and the predetermined value F2 are set by selecting the number of disc spring sets constituting the disc spring set 9 and the elastic characteristics of the disc spring unit constituting the disc spring set, and the degree of compression of the disc spring set 9 Done by adjusting. As described above, since the precompression force F1 and the predetermined value F2 are set using the preload adding member 10 and the disc spring set 9, it is possible to set the sizes thereof with extremely high accuracy.

  In addition, although the example which employ | adopted the disc spring set 9 as an elastic member was shown, if elastic force can be generated in an axial direction, other elastic members, such as a coil spring, may be used instead of the disc spring set 9 or a disc spring. It can also be used with the set 9. A precompression force can be applied by partially compressing the coil spring in advance, and a precompression force F1 and a predetermined value F2 can be set by selecting the spring characteristics and length.

  The gap 19a and the gap 19b become smaller as the crack nut 8 and the diameter increase in the state where the tensile load is increased as shown in FIG. This corresponds to the fact that the internal thread 18a of the cracking nut 8 is pushed out from the axis 6 in the diameter increasing direction so that there is no overlap with the external thread 18b of the shaft member 12.

Next, the operation of the present embodiment will be described with reference to FIGS.
In FIG. 1, a precompression force F1 of 1800 kgf or less is applied to the disc spring assembly 9, and an external force F1 that is a reaction force of the precompression force F1 in a direction that widens the interval between the first portion 51 and the second portion 52. The state of the tension load load at the time when is added is shown. The disc spring set 9 is partially bent. The overall length of the disc spring set 9 is about 115 mm, for example. The gap g of the crack nut 8 is zero as described above, and the female screw of the crack nut 8 is in a state of being completely screwed with the male screw of the shaft portion 2.

  Next, FIG. 2 shows an increased state of the tensile load. In addition to the state shown in FIG. 1, a state in which a predetermined value F2, for example, 2600 kgf, is applied as a tensile load in a direction to widen the interval between the first part 51 and the second part 52 is shown. The entire length of the disc spring set 9 is, for example, further compressed by about 5 mm and 110 mm.

  It is assumed that an external force F acts between the first part 51 and the second part 52 in a direction that widens the distance due to, for example, an earthquake. The contact member 12 is pulled toward the first portion 51, whereby the contact surface 11 a and the contact surface 11 b of the contact member 12 are respectively applied to the pressure receiving inclined surface 7 a and the pressure receiving inclined surface 7 b of the crack nut 8. The external force F is applied to the first portion 51 by abutting against the first portion 51. As a result, the crack nut 8 is pushed toward the first portion 51 to expand its diameter to form a gap g, and an external force F is transmitted from the portion of the crack nut 8 on the first portion 51 side to the disc spring assembly 9. The disc spring set 9 is compressed. Thus, the external force F is received by the compression of the disc spring assembly 9, and the crack nut 8 receives the external force F by the compressed disc spring assembly 9. As the external force F increases, the crack nut 8 decreases the degree of fitting, that is, the degree of overlap between the internal thread of the crack nut 8 and the male screw of the shaft part 2, and when the external force F reaches a predetermined value F2, the male screw of the shaft part 2 In this state, the diameter expansion of the crack nut 8 is completed. In this case, since the pressure receiving inclined surface 7a and the pressure receiving inclined surface 7b of the crack nut 8 form an acute angle with respect to the first portion 51 side, the pressure receiving inclined surface 7a and the pressure receiving inclined surface 7b are formed at an obtuse angle. Along the contact surface 11a and the contact surface 11b of the contact member 12, the crack nut 8 is smoothly guided in the direction of increasing the diameter. In addition, since the gap 19a and the gap 19b are formed, the diameter-enlarged portion of the crack nut 8 can be accommodated in the gap 19a and the gap 19b.

  Then, as a result of the crack nut 8 being enlarged in diameter and having no overlapping portion with the internal thread of the crack nut 8, the bolt 4 slides toward the first portion 51 with respect to the crack nut 8. When the external force F becomes smaller than the predetermined value F2, the cracking nut 8 is reduced in diameter, and an overlapping portion with the female screw of the cracking nut 8 is generated, and the bolt 4 slides toward the first portion 51 with respect to the cracking nut 8. The distance between the first part 51 and the second part 52 is maintained in an extended state by the amount of sliding movement.

  Thus, when the external force F is smaller than the predetermined value F2, the bolt device 1 maintains the interval between the first part 51 and the second part 52 in a steady state, and when the external force F is equal to or larger than the predetermined value F2. When the bolt 4 slides and the external force F again becomes smaller than the predetermined value F2, the bolt 4 stops sliding movement and the state where the sliding movement stops can be a new steady state.

  Further, since the bolt device 1 can slide when the external force F is applied to a predetermined value F2 or more, it functions as a tensile load overload prevention mechanism in a device to which the bolt 4 or the like is applied. be able to.

  In addition, the magnitude | size of the value of the predetermined value F2 can be determined with the fitting form of the internal thread 18a of the crack nut 8, and the external thread 18b of the axial part 2. FIG. For example, if the screw depths of the female screw 18a and the male screw 18b are increased or the screw lengths of the female screw 18a and the male screw 18b are increased, the predetermined value F2 increases. Therefore, the magnitude of the predetermined value F2 may be set according to the purpose to which the bolt device 1 is applied.

  Next, in the bolt device 1, when the effective length of the shaft portion 2 of the bolt 4 is L and the crack nut 8 is screwed with the shaft portion 2 at the root portion of the shaft portion 2, the bolt 4 is Assume a case of sliding movement with respect to the cracking nut 8.

  In this case, if the external force F becomes smaller than the predetermined value F2 when the cracking nut 8 is slid and moved by the length L, the diameter of the cracking nut 8 is reduced and the female screw of the cracking nut 8 is fitted with the male screw of the shaft portion 2. The sliding movement of the bolt device 1 stops. In this state, the distance between the first portion 51 and the second portion 52 is increased by the effective length L. In other words, the bolt device 1 can adjust the distance between the first portion 51 and the second portion 52 within the range of the effective length L of the shaft portion 2, and slides around the predetermined value F <b> 2. Is automatically controlled in the sense that the sliding movement is automatically generated or stopped by the magnitude of the external force F received by. That is, the interval between the first part 51 and the second part 52 can be automatically adjusted depending on the magnitude of the external force F.

  Next, with reference to FIG. 6, an embodiment of an expansion joint will be described as one application example of the bolt device 1. This is because the bolt device 1 can automatically adjust the distance between the first part 51 and the second part 52 within the effective length L of the shaft portion 2 as described above. Is based.

  FIG. 6 shows the upper half with respect to the central axis. The expansion joint 30 connects the first pipe 31 and the second pipe 32. The expansion joint 30 seals the sleeve 34 spanned between the end portions of the first pipe 31 and the second pipe 32, the inner peripheral surface of the sleeve 34, and the outer peripheral surface of the first pipe 31, for example, O. A ring-shaped first seal 35 and, for example, an O-ring-shaped second seal 36 that seals the inner peripheral surface of the sleeve 34 and the outer peripheral surface of the second pipe 32 are provided.

  In addition, the expansion joint 30 includes a stopper 38 for limiting the first pipe 31 and the second pipe 32 so as not to be separated beyond a predetermined length L in the axial direction. The stopper 38 includes a first reference part 39 as the first part 51 provided on the outer peripheral part of the first pipe 31 and a second reference part 34 as the second part 52 provided on the outer peripheral part of the second pipe 32. And the bolt device 1 spanned between the first reference portion 39 and the second reference portion 40. The expansion joint 30 is provided with a plurality of stoppers 38 around the axis, for example, four at intervals of 90 °.

  A plurality of first reference parts 39 and second reference parts 40 are provided on the outer peripheral surfaces of the first pipe 31 and the second pipe 32 at equal intervals, and the plurality of first reference parts 3 and the second reference parts are provided. The part 40 is provided with a plurality of equivalent stoppers 38.

  According to the present embodiment, since the stopper 38 includes the bolt device 1, the piping device including the first pipe 31, the second pipe 32, and the expansion joint 30 is buried in the ground, and is affected by an earthquake or the like. When an external force exceeding a predetermined value is received, the expansion joint 30 does not come off from the first pipe 31 and the second pipe 32, and the axial interval between the first pipe 31 and the second pipe 32 is effective for the shaft portion 2. It is possible to extend the length L.

DESCRIPTION OF SYMBOLS 1 Bolt apparatus 2 Shaft part 3 Head 4 Bolt 7 Pressure receiving inclined surface 8 Cracking nut 9 Belleville spring assembly 10 Preload addition member 11 Contact inclined surface 12 Contact member 13 Expansion member 31 First piping 32 Second piping 38 Stopper 39 First reference part 40 Second reference part 51 First part 52 Second part F1 Precompression force F2 Predetermined value

Claims (8)

A bolt device spanned between an opposing first part and a second part,
A bolt having a head abutting on the first part and a shaft part directed from the head toward the second part;
A split nut having a pressure-receiving inclined surface in which a plurality of divided units are combined and can be screwed to the shaft portion, and a surface facing the second portion in a cross-sectional view is inclined with respect to the axis; An elastic member disposed on the outer periphery of the elastic member and elastically deformable in the axial direction
A preload adding member for precompressing the elastic member and applying a precompression force to the crack nut;
A contact member having a contact inclined surface that contacts the pressure receiving inclined surface in a cross-sectional view on the opposite side of the elastic member with respect to the axis of the crack nut that receives the precompression force;
A connecting member for connecting the contact member to the second portion;
With
When an external force acts in the axial direction in the direction of expanding the distance between the first part and the second part and the external force is greater than a predetermined value, the crack nut and the bolt are screwed together. The bolt device is characterized in that the diameter of the cracking nut expands as the state is released, and the bolt slides relative to the cracking nut. The bolt device according to claim 1, wherein the elastic member is a disc spring set including a plurality of disc springs arranged in the axial direction. 2. The bolt device according to claim 1, wherein the precompression force is given by compressing the disc spring set, and the predetermined value is set as a state in which the disc spring set is further compressed. The said preload addition member has a push screw which can be screwed with respect to the housing which accommodates the said elastic member, and sets the said precompression force by the degree to which the said push screw is screwed into the said housing. Item 2. The bolt device according to Item 1. 2. The bolt device according to claim 1, wherein the pressure-receiving inclined surface forms an acute angle with respect to an axis of the shaft portion toward the first portion. The bolt device according to claim 5, wherein the predetermined angle is an angle in a range of 45 degrees to 75 degrees. The bolt device according to claim 1, wherein the crack nut has a small diameter portion and a large diameter portion. An expansion joint connecting the first pipe and the second pipe,
A stopper for limiting the first pipe and the second pipe so as not to be separated beyond a predetermined length in the axial direction;
The stopper is
A first portion provided on an outer peripheral portion of the first pipe;
A second portion provided on the outer periphery of the second pipe;
A bolt device spanned between the first part and the second part,
The bolt device is
A bolt device spanned between an opposing first part and a second part,
A bolt having a head portion attached to the first portion and a shaft portion whose axis is directed from the head portion toward the second portion;
A split nut having a pressure-receiving inclined surface in which a plurality of divided units are combined and can be screwed to the shaft portion, and a surface facing the second portion in a cross-sectional view is inclined with respect to the axis; An elastic member disposed on the outer periphery of the elastic member and elastically deformable in the axial direction
A preload adding member for precompressing the elastic member and applying a precompression force to the crack nut;
A contact member having a contact inclined surface that contacts the pressure receiving inclined surface in a cross-sectional view on the opposite side of the elastic member with respect to the axis of the crack nut that receives the precompression force;
Connection means for connecting the contact member to the second portion;
With
External force acts in the axial direction of the direction to expand their gap between said second portion and said first portion, wherein the external force is the split Re nut is expanded in diameter for a given value or more in size split Re expansion joint nut and the bolt screwed state is canceled with the bolt, characterized in that sliding movement relative to said split Re nut.

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