A device and method for preventing the opening from closing.

Abstract

The present invention provides a closure suppression device that can appropriately suppress the closing of cracks or slits that penetrate the thickness of a plate. [Solution] The closing prevention device 10 comprises a wedge member 20, a pair of pressing members 22, a bolt 24, a nut 26, and a loosening prevention mechanism 30. The wedge member 20 and the pair of pressing members 22 are arranged to be directly or indirectly clamped by the head 24a of the bolt 24 and the nut 26. With the wedge member 20 clamped by the pair of pressing members 22, the wedge member 20 and the pair of pressing members 22 are fitted into a through hole 208 formed in the metal member 200. In this state, by tightening the bolt 24 and moving the pair of pressing members 22 away from each other, a reaction force can be applied from the pair of pressing members 22 to the edge of the through hole 208. The loosening prevention mechanism 30 prevents the bolt 24 from rotating in a direction that loosens the nut 26.

Description

Technical Field

[0005]

[0001] The present invention relates to an apparatus and a method for suppressing the closing of cracks generated in a structure and slits penetrating the plate thickness.

Background Art

[0002] In structures such as buildings, bridges, ships, and cranes, fatigue cracks may occur due to repeated loads acting daily. If the fatigue cracks are left untreated, they will progress due to the repeated loads acting later. Therefore, measures such as suppressing crack progress and repair are necessary to prevent major failures such as member fracture.

[0003] Conventionally, stop holes have been used to address large fatigue cracks that penetrate the plate thickness of a member and extend several times or more the plate thickness. Specifically, a through-hole (stop hole) is formed at the tip of the fatigue crack using a drill or the like to reduce the stress concentration at the crack tip. However, since the stress that supported the portion where the cross-section was significantly lost due to the crack is applied to the tip of the stop hole, the stress at the tip of the stop hole is still quite high, and cracks may occur from there. The simplest countermeasure is to insert a bolt into the stop hole and tighten it with a washer and nut to suppress deformation around the stop hole. However, with long-term use, this countermeasure may loosen or the tightening pressure may decrease due to friction, weakening the effect. Therefore, a more effective countermeasure is required.

[0004] For example, in the fatigue crack repair method disclosed in Patent Document 1, a wedge-shaped jig (wedge means) is inserted into a stop hole provided at the tip of the fatigue crack in alignment with the opening of the stop hole, and resistance for suppressing closing is imparted to the hole end of the stop hole. Thereby, the stress fluctuation range at the hole end of the stop hole is reduced to prevent crack recurrence.

[0005] Figure 8 of Patent Document 1 shows, as a specific example, a wedge-shaped sliding jig (wedge means) comprising a first inclined surface part that is L-shaped in side view and has a bolt female thread formed thereon, a second inclined surface part that slidably abuts against the first inclined surface part, and a bolt that is screwed into the bolt female thread of the first inclined surface part. When using this wedge means, the bolt is rotated in the tightening direction with the first and second inclined surface parts fitted into the stop hole. As a result, the second inclined surface part is pushed by the tip of the bolt and moves relative to the first inclined surface part. The contact surfaces of the first and second inclined surface parts are inclined with respect to the axial direction of the bolt, and as the second inclined surface part is pushed by the bolt, it moves relative to the first inclined surface part in the axial direction of the bolt and towards the radially outward direction of the stop hole. As a result, it is possible to make close contact with the end of the stop hole and provide resistance to prevent it from closing. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-140488 [Overview of the project] [Problems that the invention aims to solve]

[0007] Patent Document 1 describes a method of continuously applying torque to a bolt using a weight or a spiral spring, but the torque applied to the bolt by these methods is small. Therefore, the force acting on the bolt from the second inclined surface component may cause the bolt to rotate in the opposite direction. If the bolt rotates in the opposite direction, the closing of the crack cannot be properly suppressed.

[0008] Therefore, the present invention aims to provide a closing suppression device and a closing suppression method that can appropriately suppress the closing of cracks or slits penetrating the thickness of a plate. [Means for solving the problem]

[0009] (1) A mouth-closing suppression device according to one embodiment of the present invention is A device used by fitting it into a through-hole provided in a metal member of a structure so as to be continuous with a crack or slit that penetrates the thickness of the metal member, A bolt having a head and a shaft, A wedge member having an insertion hole formed that penetrates in a first direction, With the bolt inserted into the insertion hole such that the tip of the shaft portion protrudes from the wedge member, a nut is fitted onto the portion of the shaft portion that protrudes from the wedge member, A pair of pressing members are provided so as to sandwich the wedge member from both sides in a second direction perpendicular to the first direction, The system includes a loosening prevention mechanism that prevents the bolt from rotating in a direction that loosens the nut, In the first direction, the wedge member and the pair of pressing members are provided to be directly or indirectly clamped by the head and the nut, By tightening the bolt or nut, the wedge member and the pair of pressing members move toward each other in the first direction, causing the pair of pressing members to move toward each other in the second direction.

[0010] (2) The anti-loosening mechanism may include a contact member that prevents the bolt from rotating in a direction that loosens the nut by contacting the shaft and the nut.

[0011] (3) The closing suppression device may further include a torque application mechanism that applies torque to at least one of the bolt and the nut to rotate the bolt and the nut in a tightening direction.

[0012] (4) The closing suppression device further comprises a winding device, The torque application mechanism includes a coil spring attached to at least one of the bolt and the nut. The winding device may be configured to be able to wind up the coil spring when the coil spring is not attached to at least one of the bolt and the nut, and to be able to remove the coil spring from the torque application mechanism when the coil spring is attached to at least one of the bolt and the nut.

[0013] (5) A method for suppressing the closing of a crack or slit penetrating the thickness of a metal member of a structure, using the above-described closing suppression device, With the wedge member sandwiched between the pair of pressing members, the wedge member and the pair of pressing members are fitted into a through hole provided in the metal member so as to be continuous with the crack or the slit that penetrates the plate thickness. This method for preventing a hole from closing involves tightening the bolt onto the nut to move the wedge member and the pair of pressing members toward each other in the first direction, and moving the pair of pressing members toward each other in the second direction, thereby applying a reaction force from the pair of pressing members toward the edge of the through hole. [Effects of the Invention]

[0014] According to the present invention, the closing of a crack or a slit penetrating the thickness of a plate can be appropriately suppressed. For example, by suppressing the displacement of both ends of a stop hole provided at the tip of a crack or a through hole (mounting hole for attaching a closing suppression device) provided in the middle of a crack so that they move closer to each other in a direction perpendicular to the crack surface, the closing of a crack can be suppressed. Also, for example, by suppressing the displacement of both ends of a stop hole provided at the tip of a slit penetrating the thickness of a plate or a through hole (mounting hole) provided in the middle of the slit so that they move closer to each other in a direction perpendicular to the length direction of the slit, the closing of a slit can be suppressed. [Brief explanation of the drawing]

[0015] [Figure 1]FIG. 1 is an external view showing a closing suppression device according to an embodiment of the present invention. [Figure 2] FIG. 2 is an external view showing a reaction force applying device. [Figure 3] FIG. 3 is an external perspective view showing a wedge member and a pair of pressing members. [Figure 4] FIG. 4 is a view showing a spring unit. [Figure 5] FIG. 5 is a view showing a hoisting device. [Figure 6] FIG. 6 is a view showing a torque applying mechanism in a state removed from the reaction force applying device. [Figure 7] FIG. 7 is a view showing the positional relationship between an adjustment mechanism and a bolt of the reaction force applying device in a state where the adjustment mechanism is attached to the reaction force applying device. [Figure 8] FIG. 8 is a view showing a crack generated in a metal member of a structure. [Figure 9] FIG. 9 is a view showing a through hole formed in a metal member of a structure. [Figure 10] FIG. 10 is a view showing a through hole formed in a metal member of a structure. [Figure 11] FIG. 11 is a view showing the reaction force applying device in a state fitted into the through hole. [Figure 12] FIG. 12 is a view showing the closing suppression device in a state where the hoisting device is removed.

Embodiments for Carrying Out the Invention

[0016] (Consideration of the Prior Art) The wedge mechanism shown in Figure 8 of Patent Document 1, mentioned above, lacks a mechanism to suppress vertical closing of the stop hole portion against cracks, and only applies a weak load in the opening direction using weights or springs. As a result of the inventor's investigation, it was found that when the load in the opening direction is weak, when a compressive load is applied to the first and second inclined surface components from the end of the stop hole, the bolt is pushed by the second inclined surface component, causing the bolt to rotate in the opposite direction, which may cause the displacement of the upper and lower ends of the stop hole, which followed the opening, to return. The wedge mechanism shown in Figure 8 of Patent Document 1 lacks a mechanism to limit the displacement of the upper and lower ends of the stop hole, and therefore cannot sufficiently suppress the crushing deformation of the stop hole portion, especially when a slow, repeated load is applied to the structure. As a result, it may not be possible to sufficiently reduce the stress fluctuation range at the tip of the stop hole during repeated loading, and it may not be possible to sufficiently prevent the recurrence of cracks.

[0017] Furthermore, Figure 17 of Patent Document 1 shows another specific example of a wedge means, which comprises a first split female thread component having a tapered female thread, a second split female thread component having a tapered female thread at one end, and a tapered bolt. When using this wedge means, the wedge means is positioned inside the stop hole so that the tapered bolt is sandwiched between the first split female thread component and the second split female thread component. In this state, when the tapered bolt is rotated in the tightening direction, the first split female thread component and the second split female thread component are pushed by the tapered bolt and move away from each other. This provides resistance to the end of the stop hole to prevent it from closing.

[0018] When using tapered bolts as a wedge, the male and female threads must be formed so that they properly engage when the tapered bolt is tightened. However, it is not possible to properly engage tapered male and female threads. This is evident from the fact that the diameter of the bolt and nut changes depending on the position where the threads engage. When the male and female threads do not properly engage when the tapered bolt is tightened, that is, when the threads only partially contact each other, the threads may chip or the frictional force of the threads may change, making it impossible to smoothly push the first and second divided female thread parts toward the end of the stop hole. As a result, sufficient resistance cannot be provided to the end of the stop hole, and when repeated loads are applied to the structure, crack closure cannot be properly suppressed.

[0019] This invention was made in consideration of the problems of the prior art described above, and is an invention that makes it possible to appropriately suppress the closing of cracks or slits that penetrate the thickness of a plate.

[0020] (Description of the embodiment) The following describes an embodiment of the present invention, specifically a mouth-closing suppression device and a mouth-closing suppression method, with reference to the drawings. Figure 1 is an external view showing a mouth-closing suppression device according to one embodiment of the present invention. In Figure 1, arrows indicating a first direction X and a second direction Y, which are orthogonal to each other, are added to clarify the positional relationship of each part of the mouth-closing suppression device 10. The first direction X and the second direction Y are also added as appropriate in the figures described later.

[0021] (Configuration of the mouth-closing prevention device) As shown in Figure 1, the mouth-closing suppression device 10 according to this embodiment (hereinafter abbreviated as suppression device 10) comprises a reaction force applying device 12 and an adjustment mechanism 14. The adjustment mechanism 14 is detachable from the reaction force applying device 12 and is provided as needed. Details of the adjustment mechanism 14 will be described later.

[0022] Figure 2 is an external view showing the reaction force applying device 12. As shown in Figure 2, the reaction force applying device 12 includes a wedge member 20, a pair of pressing members 22, a bolt 24, a nut 26, and washers 28a and 28b.

[0023] Figure 3 is an external perspective view showing the wedge member 20 and a pair of pressing members 22. In addition to the first direction X and the second direction Y, Figure 3 also includes an arrow indicating a third direction Z that is perpendicular to the first direction X and the second direction Y. The third direction Z is also indicated as appropriate in the figures described later.

[0024] As shown in Figures 2 and 3, the wedge member 20 has an insertion hole 20a that penetrates in the first direction X. The wedge member 20 is formed such that the length in the second direction Y becomes shorter on one side in the first direction X. In this embodiment, the wedge member 20 has a pair of inclined surfaces 20b that are inclined with respect to the first direction X when viewed from the third direction Z. One inclined surface 20b faces one side in the second direction Y, and the other inclined surface 20b faces the other side in the second direction Y.

[0025] A pair of pressing members 22 are provided so as to sandwich the wedge member 20 from both sides in the second direction Y. Each pressing member 22 is formed such that the length in the second direction Y is longer on one side in the first direction X. In this embodiment, each pressing member 22 has an inclined surface 22a facing the wedge member 20 side in the second direction Y, and a curved surface 22b facing outward (opposite side from the wedge member 20) in the second direction Y.

[0026] The inclined surface 22a is inclined with respect to the first direction X when viewed from the third direction Z. The curved surface 22b is curved in an arc shape so as to be convex outward in the second direction Y in a cross section perpendicular to the first direction X. A recess 22c is formed in the center of each inclined surface 22a in the third direction Z for passing the shaft portion 24b of the bolt 24, which will be described later. Each recess 22c is formed to be recessed outward in the second direction Y from the inclined surface 22a.

[0027] In this embodiment, the tip portion 20c (one end in the first direction X) of the wedge member 20 is inserted between a pair of pressing members 22 such that the inclined surface 22a of one pressing member 22 is in surface contact with one inclined surface 20b of the wedge member 20, and the inclined surface 22a of the other pressing member 22 is in surface contact with the other inclined surface 20b of the wedge member 20.

[0028] As shown in Figure 2, the bolt 24 has a head 24a and a shaft 24b. A hole 25a is formed in the center of the head 24a, opening toward one side in the first direction X. A slit 25b is also formed in the head 24a, extending from the hole 25a to the side of the head 24a. The hole 25a and the slit 25b will be described later.

[0029] A male thread is formed on the shaft portion 24b. The bolt 24 is inserted into the insertion hole 20a such that the tip portion 24c of the shaft portion 24b protrudes from the wedge member 20. In this embodiment, the tip portion 24c of the shaft portion 24b protrudes from the wedge member 20 to the other side in the first direction X. A nut 26 is fitted onto the portion of the shaft portion 24b that protrudes from the wedge member 20.

[0030] The wedge member 20 and the pair of pressing members 22 are provided between the head 24a and the nut 26 in the first direction X. In this embodiment, a washer 28a is provided between the head 24a and the pair of pressing members 22, and a washer 28b is provided between the nut 26 and the wedge member 20. In this embodiment, the wedge member 20 and the pair of pressing members 22 are indirectly clamped by the head 24a and the nut 26 via washers 28a and 28b in the first direction X.

[0031] In this embodiment, the washer 28b is provided so as not to rotate around the shaft portion 24b relative to the wedge member 20. The washer 28b may be, for example, bonded to the wedge member 20, welded, or screwed in. Alternatively, rotation of the washer 28b relative to the wedge member 20 may be prevented by, for example, a keyway. Alternatively, rotation of the washer 28b relative to the wedge member 20 may be prevented by, for example, configuring the wedge member 20 and the washer 28b so that sufficient frictional force is generated between them.

[0032] Furthermore, in this embodiment, the nut 26 is provided so as not to rotate around the shaft portion 24b relative to the wedge member 20 and the washer 28b. The nut 26 may be, for example, glued to the washer 28b, welded to it, or screwed to it. Alternatively, for example, a keyway may be used to prevent the rotation of the nut 26 relative to the washer 28b. Alternatively, for example, the rotation of the nut 26 relative to the washer 28b may be prevented by configuring the nut 26 and the washer 28b such that sufficient frictional force is generated between the nut 26 and the washer 28b.

[0033] In this embodiment, the bolt 24 and washer 28a are configured such that the frictional force (sliding resistance) between the seating surface of the bolt head 24a and the washer 28a is reduced. Rotation of the washer 28a relative to the pressing member 22 may or may not be prevented. Although a detailed explanation is omitted, washers 28a and 28b may not be provided. That is, the wedge member 20 and the pair of pressing members 22 may be directly clamped by the head 24a and the nut 26 in the first direction X. If the washer 28b is not provided, the nut 26 may be, for example, bonded to the wedge member 20, welded, or screwed in. Also, rotation of the nut 26 relative to the wedge member 20 may be prevented by, for example, a keyway. Alternatively, for example, the rotation of the nut 26 relative to the wedge member 20 may be prevented by configuring the wedge member 20 and the nut 26 such that sufficient frictional force is generated between them.

[0034] In this embodiment, when the bolt 24 rotates relative to the nut 26 such that the head 24a and the nut 26 move closer together in the first direction X, this is referred to as rotation in the tightening direction, and when the bolt 24 rotates relative to the nut 26 such that the head 24a and the nut 26 move further apart in the first direction X, this is referred to as rotation in the loosening direction.

[0035] In this embodiment, by rotating the bolt 24 in the tightening direction while the wedge member 20 is sandwiched between the pair of pressing members 22, the wedge member 20 and the pair of pressing members 22 move toward each other in the first direction X. As a result, the inclined surface 22a of each pressing member 22 is pushed outward in the second direction Y by the inclined surface 20b of the wedge member 20. Consequently, the pair of pressing members 22 move toward each other in the second direction Y.

[0036] The nut 26 is provided with an anti-loosening mechanism 30 that prevents the bolt 24 from rotating in a direction that loosens the nut 26. In this embodiment, the anti-loosening mechanism 30 includes a contact member 30a that prevents the bolt 24 from rotating in a direction that loosens the nut 26 by contacting the shaft portion 24b and the nut 26. In this embodiment, a coiled wire (coil spring) made of metal is used as the contact member 30a. When the bolt 24 attempts to rotate in a direction that loosens the nut 26, the contact member 30a prevents the rotation of the bolt 24 by being sandwiched between the male thread of the shaft portion 24b and the female thread of the nut 26.

[0037] In this embodiment, the anti-loosening mechanism 30 is configured to be set to a locked state that prevents the nut 26 from rotating relative to the shaft 24b in a loosening direction, and to a released state that allows the nut 26 to rotate relative to the shaft 24b in a loosening direction. The anti-loosening mechanism 30 is also configured to allow the nut 26 to rotate relative to the shaft 24b in a tightening direction. As the nut 26 equipped with such an anti-loosening mechanism 30, for example, a Hyper Load Nut (manufactured by Tokyo Koki Engineering Co., Ltd., registered trademark) can be used. Alternatively, as the anti-loosening mechanism 30, for example, a Hyper Load Spring (manufactured by Tokyo Koki Engineering Co., Ltd., registered trademark) that prevents a fixed nut from loosening can be used. In this case, it is necessary to install a mechanism that rotates the Hyper Load Spring in conjunction with the nut.

[0038] As shown in Figure 1, the adjustment mechanism 14 includes a torque application mechanism 16 and a winding device 18. The torque application mechanism 16 and the winding device 18 are configured to be detachable. Figure 4 shows the torque application mechanism 16, where (a) is a view of the torque application mechanism 16 from a third direction Z, and (b) is a view of the torque application mechanism 16 from a first direction X.

[0039] As shown in Figure 4, the torque application mechanism 16 has a coil spring 40. In this embodiment, a mainspring is used as the coil spring 40, but other coil springs made by winding a foil-shaped or wire-shaped metal material in a helical manner may be used. For example, a spiral spring or a string-wound spring made of a wire-shaped metal material may be used. In the following description, the coil spring 40 will be referred to as a mainspring 40. A columnar pin 42 is attached to one end of the mainspring 40, and a columnar pin 44 is attached to the other end of the mainspring 40. The end of the mainspring 40 on the pin 44 side is bent toward the center of the mainspring 40. A hole 44a is formed in the center of the pin 44, opening toward one side in the first direction X.

[0040] Figure 5 shows the hoisting device 18, where (a) is a view of the hoisting device 18 from a first direction X, (b) is a view of the hoisting device 18 from a third direction Z, and (c) is a cross-sectional view showing the CC portion of (b).

[0041] As shown in Figure 5, the winding device 18 includes a cover member 46, a handle member 48, a rotating shaft 50, a ratchet mechanism 52, and a winding pin 54. The cover member 46 has a substantially cylindrical shape with one end open. In this embodiment, the cover member 46 has a disc-shaped top plate portion 46a and a cylindrical peripheral wall portion 46b extending from the outer edge of the top plate portion 46a toward the other side in the first direction X. A slit 46c is formed in the peripheral wall portion 46b. The slit 46c is formed to extend to the other side (opposite side from the top plate portion 46a) of the peripheral wall portion 46b in the first direction X.

[0042] The handle member 48 is rotatably supported on the top plate portion 46a of the cover member 46 via a rotating shaft 50. In this embodiment, the handle member 48 is fixed to the rotating shaft 50, and the rotating shaft 50 is rotatably supported in the center of the top plate portion 46a.

[0043] The ratchet mechanism 52 is located inside the cover member 46. The ratchet mechanism 52 includes a gear 52a having multiple ratchet teeth on its outer circumference and a ratchet pawl 52b that engages with the multiple ratchet teeth of the gear 52a. The gear 52a is fixed to the rotating shaft 50 such that the rotating shaft 50 passes through the center of the gear 52a. As a result, the gear 52a rotates integrally with the rotating shaft 50 around the rotating shaft 50.

[0044] The ratchet pawl 52b is supported by the cover member 46 via a support member (not shown). In this embodiment, the ratchet pawl 52b is configured to allow rotation of the gear 52a in one direction (the direction indicated by arrow R1 in Figure 5(b); hereinafter also referred to as the R1 direction), but to prevent rotation of the gear 52a in the other direction (the direction indicated by arrow R2 in Figure 5(b); hereinafter also referred to as the R2 direction). Various known ratchet mechanism configurations can be used to allow rotation of the gear 52a in only one direction, so a detailed explanation is omitted.

[0045] The winding pin 54 is fixed to the gear 52a. In this embodiment, the winding pin 54 is provided to extend from the gear 52a toward the other side in the first direction X (opposite side from the top plate portion 46a). The winding pin 54 rotates integrally with the gear 52a around the rotation axis 50 as the gear 52a rotates around the rotation axis 50.

[0046] In this embodiment, the adjustment mechanism 14 is configured by attaching the torque application mechanism 16 to the hoisting device 18. Figure 6 shows the adjustment mechanism 14, where (a) is a view of the adjustment mechanism 14 from the third direction Z, and (b) is a cross-sectional view showing the BB portion of (a).

[0047] As shown in Figure 6, when combining the torque application mechanism 16 and the winding device 18, the mainspring 40 is fitted into the cover member 46 so that the rotating shaft 50 of the winding device 18 is inserted into the hole 44a of the pin 44 of the torque application mechanism 16 (see Figure 6(a)). At this time, the end of the mainspring 40 on the pin 42 side is fitted into the slit 46c (see Figure 5(b)). In this state, by rotating the handle member 48 in the R1 direction, the winding pin 54 rotates in the R1 direction. At this time, the winding pin 54 catches on the end of the mainspring 40 on the pin 44 side (the bent portion), causing the end of the mainspring 40 on the pin 44 side to rotate in the R1 direction. As a result, the mainspring 40 is wound up. As mentioned above, the rotation of the gear 52a in the R2 direction is prevented by the ratchet pawl 52b. Therefore, even if a force is applied from the mainspring 40 to the winding pin 54 attempting to rotate it in the R2 direction, the winding pin 54 is prevented from rotating in the R2 direction. This prevents the mainspring 40 from unwinding.

[0048] Figure 7 shows the positional relationship between the adjustment mechanism 14 and the bolt 24 of the reaction force applying device 12 when the adjustment mechanism 14 is attached to the reaction force applying device 12 (as shown in Figure 1). As shown in Figures 1 and 7, when attaching the adjustment mechanism 14 to the reaction force applying device 12, the pin 44 of the torque applying mechanism 16 is inserted into the hole 25a of the head 24a of the bolt 24, and the end of the mainspring 40 on the pin 44 side (the bent portion) is inserted into the slit 25b of the head 24a. This connects the mainspring 40 to the head 24a of the bolt 24.

[0049] (Method for suppressing mouth closure) Next, a method for suppressing crack closure using the suppression device 10 described above will be explained. Figure 8 shows an example of a crack whose closure is suppressed using the suppression device 10. Figure 8 shows a crack 202 that has occurred in a metal member 200 of a structure. The metal member 200 is, for example, a steel plate with a thickness of about 9 to 16 mm. The following explanation of how to use the suppression device 10 is also applicable when suppressing the closure of a slit that penetrates the plate thickness of the metal member 200 of the structure; the crack 202 should be replaced with the slit. Furthermore, the following explanation describes a method for suppressing crack closure when the suppression device is installed on a plate-shaped metal member, but it is also possible to install the suppression device on metal members that are not plate-shaped, such as structural steel or steel pipes, in which case the plate thickness will be the thickness or wall thickness depending on the shape.

[0050] In the crack closing suppression method according to this embodiment, as shown in Figure 9, through holes 204, 206, and 208 are formed in the metal member 200 so as to be continuous with the crack 202. In the example shown in Figure 9, through holes 204 and 206 are formed so as to be continuous with both ends of the crack 202, and through hole 208 is formed so as to be continuous with the center of the crack 202. In the following description, the case in which the suppression device 10 is provided in the through hole 208 formed in the center of the crack 202 will be described, but the suppression device 10 may also be provided in the through holes 204 and 206. Also, if the suppression device 10 is provided in the through hole 208, the through holes 204 and 206 do not need to be formed. The suppression device 10 may be provided in the through hole 208, and bolts may be inserted into the through holes 204 and 206 and tightened with washers and nuts. Also, if the suppression device 10 is provided in the through holes 204 and 206, the through hole 208 does not need to be formed.

[0051] Figure 10 is an enlarged view showing the through-hole 208 and its surroundings in the metal member 200. As shown in Figure 10, in this embodiment, a smaller insertion hole 210 is further formed near the through-hole 208. In this embodiment, the insertion hole 210 is formed in the metal member 200 so as to penetrate the thickness of the plate.

[0052] Next, the reaction force applying device 12 is fitted into the through hole 208. Figure 11 shows the reaction force applying device 12 fitted into the through hole 208. Note that Figure 11 shows a cross-section of the metal member 200 corresponding to part AA in Figure 10. As shown in Figure 11, in this embodiment, the reaction force applying device 12 is fitted inside the through hole 208 so that the pair of pressing members 22 are positioned inside the through hole 208. Also, in this embodiment, the reaction force applying device 12 is fitted into the through hole 208 so that the wedge member 20 is sandwiched by the pair of pressing members 22 in a direction perpendicular to the longitudinal direction of the crack 202 (Figure 10). In other words, the reaction force applying device 12 is fitted into the through hole 208 so that the second direction Y of the suppression device 10 is perpendicular to the crack surface. In this state, the bolt 24 is rotated in the tightening direction, moving the wedge member 20 and the pair of pressing members 22 toward each other in the first direction X1. This allows the pair of pressing members 22 to move toward each other in the second direction Y, and a reaction force can be applied from the pair of pressing members 22 toward the edge of the through hole 208.

[0053] Next, if necessary, the adjustment mechanism 14 with the mainspring 40 wound up is attached to the reaction force applying device 12. Specifically, as described above, the adjustment mechanism 14 is attached to the reaction force applying device 12 so that the mainspring 40 is connected to the head 24a of the bolt 24. At this time, the pin 42 (see Figure 6) of the torque applying mechanism 16 (see Figure 6) is inserted into the insertion hole 210 (see Figure 10). After that, as shown in Figure 12, the winding device 18 is removed from the reaction force applying device 12, leaving the torque applying mechanism 16 in place. This applies torque from the mainspring 40 to the bolt 24 (head 24a) to rotate the bolt 24 in the tightening direction. If the mainspring 40 can be compactly fitted, the insertion hole 210 may be provided at a position that penetrates the washer 28a and one of the pressing members 22 instead of the metal member 200. Furthermore, if the washer 28a and the pressing member 22 are provided with insertion holes 210, the insertion holes 210 do not need to penetrate the pressing member 22.

[0054] (Effects and Benefits) In the suppression device 10 according to this embodiment, the wedge member 20 and the pair of pressing members 22 can be moved toward each other by rotating the bolt 24 in the tightening direction to bring the head 24a and the nut 26 closer together in the first direction X. As a result, the wedge member 20 can push the pair of pressing members 22 outward in the second direction Y. Consequently, the pair of pressing members 22 move toward each other in the second direction Y, and a reaction force can be applied from the pair of pressing members 22 to the edge of the through hole 208.

[0055] Thus, in this embodiment, by bringing the head 24a and the nut 26 closer together in the first direction X, the pair of pressing members 22 can be moved away from each other in the second direction Y. In this case, it is not necessary to form tapered male and female threads to move the pair of pressing members 22 away from each other in the second direction Y. In other words, the pair of pressing members 22 can be smoothly moved outward in the second direction Y by the wedge member 20 without using tapered male and female threads. As a result, when the load applied to the metal member 200 is removed, a reaction force can be appropriately applied from the pair of pressing members 22 to the edge of the through hole 208, thereby suppressing the closing of the crack 202.

[0056] Furthermore, the suppression device 10 according to this embodiment is equipped with a loosening prevention mechanism 30 that prevents the bolt 24 from rotating in a loosening direction. As a result, even if a force is applied to the bolt 24 that causes it to rotate in a loosening direction when the load acting on the metal member 200 is removed (when the crack 202 closes), the bolt 24 is prevented from loosening. In other words, the pair of pressing members 22 are prevented from moving toward each other in the second direction Y. In this case, it is possible to suppress displacement of both ends of the through hole 208 in the direction perpendicular to the crack surface (the direction perpendicular to the length direction of the crack 202) toward each other. As a result, the closing of the crack 202 can be appropriately suppressed.

[0057] As described above, the suppression device 10 according to this embodiment can appropriately apply a reaction force to the edge of the through hole 208 from the pair of pressing members 22, and can suppress displacement at the edge of the through hole 208 in a direction perpendicular to the crack surface, causing both ends to move closer to each other. As a result, when repeated loads are applied to the metal member 200, the closing of the crack 202 can be appropriately suppressed. As a result, the stress fluctuation range at the edges of the through holes 204 and 206 formed at both ends of the crack 202 can be sufficiently reduced, and the occurrence of new cracks in the through holes 204 and 206 can be prevented. Furthermore, if the through holes 204 and 206 are not formed, the stress fluctuation range at both ends (tip) of the crack 202 can be sufficiently reduced, and the propagation of the crack can be sufficiently suppressed. Similarly, when the suppression device 10 is provided in the through holes 204 and 206, the closing of the crack 202 can be appropriately suppressed, and the stress fluctuation range at the edges of the through holes 204 and 206 can be sufficiently reduced. As a result, it is possible to prevent new cracks from forming in the through holes 204 and 206.

[0058] Furthermore, when repeated loads are applied to the metal member 200, the range of opening and closing of the crack 202 is larger in the center of the crack 202 than at both ends of the crack 202. Therefore, providing the suppression device 10 in the through hole 208 formed in the center of the crack 202 is more effective in suppressing the closing of the crack 202 than providing the suppression device 10 in the through holes 204 and 206 formed at both ends of the crack 202. If the suppression device 10 is provided in the through hole 208 and bolts are inserted into the through holes 204 and 206 and tightened with washers and nuts, it can be expected that the loosening of the bolts will be reduced. If the displacement of the crack 202 increases due to repeated loads, the bolts 24 may be rotated in the tightening direction, and the pair of pressing members 22 may be moved away from each other in the second direction Y.

[0059] In the suppression device 10 according to this embodiment, an adjustment mechanism 14 can be installed in the reaction force applying device 12 as needed. The torque applying mechanism 16 of the adjustment mechanism 14 can apply torque to the bolt 24 for rotation in the tightening direction over a long period of time. As a result, when a load is applied to the metal member 200 and a crack 202 opens, causing both ends of the through hole 208 perpendicular to the crack surface to displace away from each other, the pair of pressing members 22 can follow this displacement. Subsequently, when the load applied to the metal member 200 is removed, as described above, the loosening prevention mechanism 30 can prevent the bolt 24 from loosening, so that a reaction force can be appropriately applied from the pair of pressing members 22 to the edge of the through hole 208, and the displacement of both ends of the through hole 208 toward each other can be suppressed. In other words, when a load is repeatedly applied to the metal member 200, the displacement of both ends of the through hole 208 toward each other can be maintained, and the occurrence of displacement toward each other can be suppressed. As a result, the range of crack opening and closing can be sufficiently reduced, and the occurrence of new cracks or crack propagation can be sufficiently suppressed. As mentioned above, in this embodiment, the nut 26 is provided so as not to rotate relative to the wedge member 20 and washer 28b. This prevents the nut 26 from rotating together with the bolt 24 when the bolt 24 rotates due to the torque applied by the torque mechanism 16.

[0060] In the suppression device 10 according to this embodiment, the winding device 18 is configured so that the mainspring 40 of the torque-applying mechanism 16 can be removed from the torque-applying mechanism 16 while it is attached to the reaction force-applying device 12 (bolt 24). In this case, the suppression device 10 provided on the metal member 200 can be miniaturized. In addition, a common winding device 18 can be used for multiple suppression devices 10, so costs can be reduced.

[0061] Furthermore, when using a spring other than a coil spring, such as a string winding spring, as the coil spring 40, a torque application mechanism should be appropriately configured to apply torque to the bolt 24 in the same way as when using a mainspring, and a winding device should be appropriately configured to wind the spring in the same way as when winding a mainspring.

[0062] The dimensions of each part of the suppression device 10 are set appropriately according to the strength and thickness of the metal member 200, the applied stress, the crack dimensions, etc., in order to perform the functions described above. For example, the size of the through hole 208 can be adjusted according to the strength of the metal member 200, or the dimensions (pitch) of the bolts 24 can be adjusted according to the dimensions of the crack 202 or slit. Alternatively, for example, the dimensions of the pressing member 22 can be increased to ensure the strength of the pressing member 22.

[0063] The materials for each part of the suppression device 10 are appropriately selected considering the strength and thickness of the metal member 200. For example, it is desirable to use SCM435 (chromium-molybdenum steel), a structural alloy steel, and to achieve a hardness of HRC33 or higher through heat treatment.

[0064] (modified version) In the embodiment described above, the case in which the bolt 24 is inserted from the washer 28a side toward the washer 28b side was explained, as shown in Figure 2. However, the orientation of the bolt 24 may be reversed from that of the embodiment described above. That is, in the reaction force applying device 12 shown in Figure 2, the bolt 24 may be inserted from the washer 28b side toward the washer 28a side.

[0065] In the above embodiment, the case in which torque is applied to the bolt 24 from the torque application mechanism 16 was described, but the torque application mechanism 16 and the nut 26 may be configured so that torque can be applied to the nut 26 from the torque application mechanism 16. In this case, the nut 26 is provided so that it can rotate around the shaft portion 24b relative to the wedge member 20 and washer 28b, and the bolt 24 and washer 28a are provided so that they cannot rotate around the shaft portion 24b relative to the pair of pressing members 22. Alternatively, a torque application mechanism may be provided so that torque can be applied to the bolt 24 and the nut 26 respectively. In this case, a torque application mechanism may be provided for the bolt 24 and the nut 26 respectively.

[0066] In the above-described embodiment, a torque application mechanism 16 utilizing a coil spring 40 was explained, but the configuration of the torque application mechanism is not particularly limited as long as it can apply torque to the bolt 24 or nut 26. For example, a motor controlled to apply torque to the bolt 24 or nut 26 when a crack opens may be used as the torque application mechanism. In this case, for example, the opening of the crack may be detected by a piezoelectric element or the like, and the motor may be controlled accordingly.

[0067] In the above-described embodiment, the case in which the anti-loosening mechanism 30 includes a coil spring as a contact member 30a was explained, but the anti-loosening mechanism only needs to be configured to prevent the bolt 24 from loosening. Therefore, the configuration of the anti-loosening mechanism is not limited to the above example, and the anti-loosening mechanism may be configured to prevent the bolt 24 from loosening using a member other than a nut with an anti-loosening mechanism that has a coil spring attached inside the nut.

[0068] In the above-described embodiment, the case in which the suppression device 10 is fitted into through holes 204, 206, and 208 formed to be continuous with the crack 202 was explained. However, the through holes into which the suppression device 10 is fitted are not limited to through holes formed after crack initiation. For example, if a fatigue crack is occurring from the weld toe within a scallop, the suppression device 10 may be fitted into the scallop. [Industrial applicability]

[0069] According to the present invention, the closing of cracks or slits that penetrate the plate thickness can be appropriately suppressed. [Explanation of Symbols]

[0070] 10 Mouth closure suppression device 12 Reaction force application device 14 Adjustment mechanism 16 Torque application mechanism 18. Hoisting device 20 Wedge member 22 Pressing member 24 volts 26 nuts 30. Anti-loosening mechanism 40 coil springs

Claims

1. A device used by fitting it into a through-hole provided in a metal member of a structure so as to be continuous with a crack or slit that penetrates the thickness of the metal member, A bolt having a head and a shaft, A wedge member having an insertion hole formed that penetrates in the first direction, With the bolt inserted into the insertion hole such that the tip of the shaft portion protrudes from the wedge member, a nut is fitted onto the portion of the shaft portion that protrudes from the wedge member, A pair of pressing members are provided so as to sandwich the wedge member from both sides in a second direction perpendicular to the first direction, The system includes a loosening prevention mechanism that prevents the bolt from rotating in a direction that loosens the nut, In the first direction, the wedge member and the pair of pressing members are provided to be directly or indirectly clamped by the head and the nut, A closing prevention device wherein, by tightening the bolt or nut, the wedge member and the pair of pressing members move toward each other in the first direction, and the pair of pressing members move toward each other in the second direction.

2. The closing prevention device according to claim 1, wherein the loosening prevention mechanism includes a contact member that contacts the shaft and the nut to prevent the bolt from rotating in a direction that loosens the nut.

3. The closing suppression device according to claim 1, further comprising a torque applying mechanism for applying torque to at least one of the bolt and the nut to rotate at least one of the bolt and the nut in a tightening direction.

4. Equipped with an additional winding device, The torque application mechanism includes a coil spring attached to at least one of the bolt and the nut. The closing suppression device according to claim 3, wherein the winding device is configured to be able to wind up the coil spring when the coil spring is not attached to at least one of the bolt and the nut, and to be able to remove the coil spring from the torque application mechanism when the coil spring is attached to at least one of the bolt and the nut.

5. A method for suppressing the closing of a crack or slit penetrating the thickness of a metal member of a structure, using a closing suppression device described in any one of claims 1 to 4, With the wedge member sandwiched between the pair of pressing members, the wedge member and the pair of pressing members are fitted into a through hole provided in the metal member so as to be continuous with the crack or the slit that penetrates the plate thickness. A method for preventing a hole from closing, wherein the bolt is tightened onto the nut to move the wedge member and the pair of pressing members toward each other in the first direction, and the pair of pressing members are moved toward each other in the second direction, thereby applying a reaction force from the pair of pressing members toward the edge of the through hole.

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