One-sided bolt anti-loosening device
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- SANKO TECHNO
- Filing Date
- 2022-10-14
- Publication Date
- 2026-06-05
Smart Images
Figure 0007870704000001 
Figure 0007870704000002 
Figure 0007870704000003
Abstract
Description
Technical Field
[0001] The present invention relates to a bolt dropout prevention tool for one-sided bolts.
Background Art
[0002] When fastening two members, when using a bolt and a nut to fasten the members, it is common to hold the nut on the back side of the member and rotate the head of the bolt from the front side. However, depending on the working situation, it may not be possible to hold the nut on the back side. In this case, bolts that can be fastened only by working from one side of the member, so-called one-sided bolts, have been conventionally used. As one form of the one-sided bolt, a bolt having a bolt and a sleeve through which the bolt is inserted is known. In order to improve the reliability of fastening with a one-sided bolt, it is required to prevent the bolt from dropping out of the sleeve.
[0003] The following Patent Document 1 discloses a screw retention structure having an engagement hole formed around a screw insertion hole of a fastened member and an annular retaining clip having an engagement means that can be engaged and disengaged with the engagement hole.
[0004] The following Patent Document 2 discloses a bolt retention structure that is composed of a fastened member and a bolt, and a pressing portion that rises upward in the axial direction of the bolt from around the bolt head is provided on the fastened member, and the bolt head is pressed by bending the pressing portion to prevent the bolt from coming out of the fastened member.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0006] The retaining structures described in Patent Documents 1 and 2 above are not intended for one-sided bolts, and it is difficult to apply these structures directly to one-sided bolts. Furthermore, even if one were to attempt to apply these structures to one-sided bolts, it would be necessary to pre-form the engagement holes and retaining parts in the fastened material to which the bolt is fastened. Therefore, adopting these structures would increase the effort and cost required for processing the fastened material, resulting in low versatility. [Means for solving the problem]
[0007] To solve the above problems, the one-sided bolt fall prevention device according to embodiment 1 of the present invention is used for a one-sided bolt comprising a bolt having a bolt head and a sleeve having a sleeve head, and prevents the bolt from falling out of the sleeve, comprising a sleeve mounting member attached to the sleeve head and a bolt mounting member attached to the bolt head, wherein the sleeve mounting member has a top plate portion facing the top surface of the sleeve head, a side plate portion extending from the top plate portion along the side surface of the sleeve head and restricting the relative rotation of the sleeve and the sleeve mounting device with respect to the central axis of the bolt, and a projection extending from the top plate portion in a direction different from the extending direction of the side plate portion, and the bolt mounting device has a fitting hole that fits onto the bolt head and restricts the relative rotation of the bolt and the bolt mounting device with respect to the central axis, and an insertion hole through which the projection of the sleeve mounting device is inserted.
[0008] According to the configuration of Embodiment 1 of the present invention, the relative rotation of the sleeve mounting member and the sleeve around the central axis is restricted by the side plate portion. Therefore, if the sleeve attempts to rotate in one direction, the sleeve mounting member will also attempt to rotate in the same direction. On the other hand, the fitting hole fits onto the bolt head, restricting the relative rotation of the bolt mounting member and the bolt around the central axis. Therefore, if the bolt attempts to rotate in one direction, the bolt mounting member will also attempt to rotate in the same direction. Furthermore, the projection of the sleeve mounting member is inserted into the insertion hole, restricting the relative rotation of the sleeve mounting member and the bolt mounting member around the central axis. As a result, the bolt is unable to rotate freely relative to the sleeve, preventing the bolt from falling out of the sleeve. Thus, according to the configuration of Embodiment 1, the bolt can be prevented from falling out simply by using a one-side bolt fall prevention device, without any processing of the fastened material.
[0009] The anti-loosening device for one-sided bolts according to embodiment 2 of the present invention is the anti-loosening device for one-sided bolts according to embodiment 1, wherein the projection is bendable while inserted through the insertion hole of the bolt mounting member.
[0010] According to the configuration of aspect 2 of the present invention, by bending the projection piece while it is inserted through the insertion hole of the bolt mounting member, the projection piece does not come out of the insertion hole, and the sleeve mounting member and the bolt mounting member are securely connected. Therefore, the bolt can be reliably prevented from falling out.
[0011] The anti-loosening device for one-sided bolts according to embodiment 3 of the present invention is the anti-loosening device for one-sided bolts according to embodiment 1 or embodiment 2, wherein the sleeve head is hexagonal prism-shaped, and the side plate portion is provided along four of the six sides.
[0012] According to the configuration of aspect 3 of the present invention, the side plate portion of the sleeve mounting member abuts against each of the four of the six sides of the sleeve head, so that the sleeve mounting member and the sleeve are securely fixed together, and relative rotation between the sleeve mounting member and the sleeve is reliably restricted.
[0013] The anti-loosening device for one-sided bolts according to embodiment 4 of the present invention is the anti-loosening device for one-sided bolts according to embodiment 3, wherein the width of the top plate portion in the direction perpendicular to the two edges of the top plate portion where the side plate portion is not provided is substantially the same as the width of the sleeve head portion in the direction perpendicular to the two sides of the sleeve head portion which are parallel to each other.
[0014] According to the configuration of aspect 4 of the present invention, when installing a one-sided bolt, the two parallel sides exposed from the side plate portion of the sleeve head can be securely held using a tool such as a wrench. This improves the workability when fastening the bolt to the sleeve.
[0015] A one-sided bolt fall prevention device according to Embodiment 5 of the present invention is a one-sided bolt fall prevention device according to any one of Embodiments 1 to 4, wherein the bolt head is hexagonal, and the fitting hole is a dodecagonal hole having 12 recesses, each capable of fitting with any one corner of the bolt head.
[0016] According to the configuration of aspect 5 of the present invention, for example, even if the fitting hole is a hexagonal hole corresponding to the bolt head, the bolt mounting member can be attached to the bolt. However, in the case of a hexagonal hole, depending on the rotational positional relationship between the fitting hole and the bolt head when fitting the fitting hole to the bolt head, it may be necessary to rotate the bolt mounting member by up to 60 degrees relative to the bolt. In contrast, if the fitting hole is a dodecagonal hole having 12 recesses that can be fitted to any one corner of the bolt head, the rotation angle of the bolt mounting member relative to the bolt when fitting the fitting hole to the bolt head is limited to a maximum of 30 degrees. Therefore, when the fitting hole is a dodecagonal hole, it is easier to attach the bolt mounting member to the bolt and the workability of the attachment can be improved compared to when the fitting hole is a hexagonal hole.
[0017] A one-sided bolt fall prevention device according to embodiment 6 of the present invention is the one-sided bolt fall prevention device according to embodiment 5, wherein the insertion hole is an elongated hole extending in the circumferential direction when viewed from the central axis direction, and the angle between the two circumferential ends of the elongated hole with respect to the central axis is 30 degrees or more.
[0018] According to the configuration of Aspect 6 of the present invention, as described above, when the fitting hole is a 12-sided hole, the rotation angle of the bolt mounting member with respect to the bolt when fitting the fitting hole with the bolt head is at most 30 degrees. Therefore, if the angle between the two ends in the circumferential direction of the long hole is 30 degrees or more, even if the rotational position of the fitting hole and the bolt head is adjusted, the protruding piece of the sleeve mounting member can be inserted into the insertion hole of the bolt mounting member without any problem. Also, even if the bolt rotates with respect to the sleeve within the range where the protruding piece can move along the circumferential direction of the long hole, further rotation is restricted when the protruding piece abuts against the end of the long hole. Therefore, it is possible to surely prevent the bolt from falling off the sleeve while ensuring the workability of mounting the one-sided bolt anti-drop tool.
Brief Description of the Drawings
[0019] [Figure 1] It is a perspective view of a sleeve mounting member constituting an anti-drop tool for a one-sided bolt. [Figure 2] It is a plan view of a bolt mounting member constituting an anti-drop tool for a one-sided bolt. [Figure 3] It is a perspective view of a bolt. [Figure 4] It is a perspective view of a sleeve. The [Figure 5] It is a perspective view showing a state where an anti-drop tool for a one-sided bolt is mounted on a one-sided bolt. [Figure 6] It is a cross-sectional view showing the first step of the construction method of a one-sided bolt. [Figure 7] It is a cross-sectional view showing the second step of the construction method of a one-sided bolt. [Figure 8] It is a plan view showing the third step of the construction method of a one-sided bolt. [[ID=No. 32]] [Figure 9] It is a cross-sectional view showing the main part of the third step of the construction method. [Figure 10] It is a plan view showing the fourth step of the construction method of a one-sided bolt. [Figure 11] It is a cross-sectional view showing the main part of the fourth step of the construction method. [Figure 12]This is a perspective view showing the configuration of a modified one-sided bolt. [Modes for carrying out the invention]
[0020] Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the dimensions of each component may be shown on a different scale to make them easier to see. In the following explanation, the anti-loosening device for one-sided bolts will be simply referred to as the anti-loosening device.
[0021] Figure 1 is a perspective view of the sleeve mounting member 11 that constitutes the fall prevention device 10. Figure 2 is a plan view of the bolt mounting member 12 that constitutes the fall prevention device 10. Figure 3 is a perspective view of the bolt 31 that constitutes the one-side bolt 30. Figure 4 is a perspective view of the sleeve 32 that constitutes the one-side bolt 30.
[0022] As shown in Figures 1 and 2, the fall prevention device 10 of this embodiment comprises a sleeve mounting member 11 and a bolt mounting member 12. As shown in Figures 3 and 4, the one-sided bolt 30 of this embodiment comprises a bolt 31 and a sleeve 32 through which the bolt 31 is inserted. The one-sided bolt 30 is used, for example, to fasten fastened materials to square steel pipes that constitute columns and beams. When fastening a bolt to a steel pipe, it is not possible to hold the nut inside the steel pipe, so the one-sided bolt 30 is used. However, the use of the one-sided bolt 30 is not limited to this and can be used for various purposes.
[0023] As shown in Figure 3, the bolt 31 has a bolt head 311 and a male threaded portion 312. The bolt head 311 has a hexagonal prism shape and has a top surface 311a and six side surfaces 311b. That is, the shape of the bolt head 311 when viewed from the direction of the central axis C of the bolt 31 is hexagonal. In the one-side bolt 30, the central axis C of the bolt 31 is also the central axis of the sleeve 32. In the following description, names such as top surface, side surface, top plate portion, and side plate portion will be used for each part, but these names are used for convenience of explanation and do not limit the orientation or position when using the one-side bolt.
[0024] As shown in Figure 4, the sleeve 32 has a sleeve head 321 and a sleeve tube portion 322. In the sleeve 32 of this embodiment, the sleeve head 321 and the sleeve tube portion 322 are integrally formed. A through hole 323 for inserting a bolt 31 is provided across the sleeve head 321 and the sleeve tube portion 322. The sleeve tube portion 322 has a plurality of slits 324 provided at predetermined intervals in the circumferential direction. In this embodiment, four slits 324 are provided. On the inner surface of the sleeve tube portion 322 on the tip side of the slits 324, a female thread portion 325 is formed to screw with the male thread portion 312 of the bolt 31. The sleeve head 321 has a hexagonal prism shape and has a top surface 321a and six side surfaces 321b. In this embodiment, the outer shape of the sleeve head 321 as viewed from the direction of the central axis C is a regular hexagon.
[0025] As shown in Figure 1, the sleeve mounting member 11 has a top plate portion 111, four side plate portions 112, and two protruding pieces 113. The top plate portion 111, the side plate portions 112, and the protruding pieces 113 are integrally formed by bending a metal plate material. The sleeve mounting member 11 is attached to the sleeve head portion 321, as will be described later.
[0026] The top plate portion 111 has a regular hexagonal shape and faces the top surface 321a of the sleeve head 321 when mounted on the sleeve head 321. A circular hole 111h is provided in the center of the top plate portion 111 through which the male threaded portion 312 of the bolt 31 is inserted.
[0027] The side plate portion 112 extends from the edge of the top plate portion 111 along the side surface 321b of the sleeve head portion 321 when attached to the sleeve head portion 321. The height h1 of the side plate portion 112 is less than or equal to the height h2 of the sleeve head portion 321 (see Figure 4). The four side plate portions 112 are provided so as to follow four of the six side surfaces 321b of the sleeve head portion 321, excluding the two side surfaces 321b that are parallel to each other. In the top plate portion 111, the width w1 in the direction perpendicular to the two edges where the side plate portions 112 are not provided is approximately equal to the width w2 (see Figure 4) in the direction perpendicular to the two parallel side surfaces 321b of the sleeve head portion 321.
[0028] The projection 113 extends in the direction opposite to the direction in which the side plate portion 112 extends from the top plate portion 111. The projection 113 is made bendable using a tool such as pliers while inserted through the insertion hole 122 of the bolt mounting member 12, which will be described later. The two projections 113 are provided at the corners of the top plate portion 111, which are located between two adjacent side plate portions 112.
[0029] As shown in Figure 2, the bolt mounting member 12 is formed from a metal plate. The bolt mounting member 12 has a fitting hole 121 and two through holes 122. The bolt mounting member 12 is attached to the bolt head 311, as will be described later.
[0030] The fitting hole 121 is formed in the center of the bolt mounting member 12 and fits onto the bolt head 311. The fitting hole 121 is composed of a dodecagonal hole having 12 recesses 121c, each of which can fit onto any one corner of the bolt head 311. That is, each recess 121c of the fitting hole 121 has the shape of an isosceles triangle with a vertex angle θ of 120 degrees.
[0031] The insertion holes 122 are elongated, arc-shaped holes that extend circumferentially when viewed from the direction of the central axis C. The two insertion holes 122 are formed opposite each other with the fitting hole 121 in between. The angle α between the two circumferential ends of the insertion holes 122 with respect to the central axis C is 30 degrees or more. As will be described later, each projection 113 of the sleeve mounting member 11 is inserted through each insertion hole 122.
[0032] The installation method for the one-sided bolt 30 and the method for preventing the bolt 31 from falling out using the anti-loosening device 10 will be explained below with reference to Figures 5 to 11.
[0033] As shown in Figure 6, the fastened material 50 has a mounting hole 50h pre-formed therein, which has a diameter through which the sleeve 32 can be inserted. Here, the multiple plate materials shown in the drawing are collectively referred to as the fastened material 50. When attaching the one-side bolt 30 to the fastened material 50, the sleeve mounting member 11 is first attached to the sleeve 32.
[0034] At this time, the sleeve mounting member 11 is positioned so that each side plate portion 112 of the sleeve mounting member 11 faces each side surface 321b of the sleeve head 321. In this state, the top plate portion 111 of the sleeve mounting member 11 abuts against the top surface 321a of the sleeve head 321, and the side plate portions 112 abut against the side surfaces 321b. Alternatively, there may be small gaps between the top plate portion 111 and the top surface 321a, and between the side plate portions 112 and the side surfaces 321b.
[0035] As a result, relative rotation between the sleeve 32 and the sleeve mounting member 11 around the central axis C is restricted, and if either the sleeve 32 or the sleeve mounting member 11 attempts to rotate, the other will also attempt to rotate accordingly. In this embodiment, since the side plate portion 112 abuts against each of the four of the six side surfaces 321b of the sleeve head 321, the sleeve mounting member 11 and the sleeve 32 are securely fixed together, and relative rotation between the sleeve mounting member 11 and the sleeve 32 is reliably restricted.
[0036] Next, the male threaded portion 312 of the bolt 31 is inserted through the hole 111h (see Figure 1) of the sleeve mounting member 11 and screwed into the female threaded portion 325 of the sleeve 32. At this time, a flat washer 36 is interposed between the bolt head 311 of the bolt 31 and the sleeve mounting member 11. Next, the sleeve 32, to which the bolt 31 is attached together with the sleeve mounting member 11, is inserted through the mounting hole 50h of the fastened material 50. At this time, a flat washer 35 is interposed between the sleeve head 321 and the mounting surface 50a of the fastened material 50. Alternatively, a tortoise-shell or dome washer with a tightening confirmation function may be used instead of the flat washer 35. The flat washer 35 may also be omitted if necessary.
[0037] Next, the sleeve head 321 is held using a tool such as a wrench (not shown), and the sleeve 32 is held down to prevent it from rotating. At this time, the wrench can be brought into contact with the two surfaces of the sleeve head 321 that are exposed from the side plate portion 112. Here, since the width w1 of the top plate portion 111 and the width w2 of the sleeve head 321 are approximately the same, the wrench can securely hold the sleeve head 321 without interfering with the top plate portion 111. This improves the workability when fastening the bolt 31 to the sleeve 32.
[0038] As described above, with the sleeve 32 fixed, the bolt 31 is rotated around the central axis C using a tool such as an impact driver (not shown). As a result, since the female thread portion 325 is formed at the tip of the sleeve pipe portion 322, the tip of the sleeve pipe portion 322 is pulled towards the back surface 50b of the material to be fastened 50. At this time, as shown in Figure 7, when a load of a certain amount or more is applied to the sleeve pipe portion 322, the area of the sleeve pipe portion 322 in which the slit 324 is formed buckles so that it opens radially outward. Finally, when the buckled portion 322a of the sleeve pipe portion 322 is pressed against the back surface 50b of the material to be fastened 50, the one-sided bolt 30 consisting of the sleeve 32 and the bolt 31 can be fixed to the material to be fastened 50 without using a nut. In this process, for example, after the initial tightening of the bolt 31 using an impact driver, the final tightening of the bolt 31 with a predetermined tightening torque may be performed using a torque wrench.
[0039] Next, as shown in Figures 8 and 9, the bolt mounting member 12 is attached to the bolt head 311. At this time, if the bolt mounting member 12 is positioned in the fitting hole 121 such that one corner of the bolt head 311 fits into one of the two adjacent recesses 121c located near the insertion hole 122, the fitting hole 121 can be fitted to the entire bolt head 311. Therefore, even if the orientation of the fitting hole 121 is such that it does not fit to the bolt head 311 when attempting to attach the bolt mounting member 12 to the bolt head 311, the bolt mounting member 12 can be fitted to the bolt head 311 by rotating the bolt mounting member 12 at an angle of 30 degrees or less relative to the bolt head 311.
[0040] Even if the fitting hole were a hexagonal hole corresponding to the bolt head, it would still be possible to attach the bolt mounting member to the bolt. However, in this case, the bolt mounting member would need to be rotated up to 60 degrees relative to the bolt when fitting the fitting hole to the bolt head. In contrast, as in this embodiment, if the fitting hole 121 is a dodecagonal hole, the rotation angle of the bolt mounting member 12 when fitting the fitting hole 121 to the bolt head 311 is limited to a maximum of 30 degrees. Therefore, in this embodiment, compared to the case where the fitting hole is a hexagonal hole, it is easier to attach the bolt mounting member 12, improving work efficiency.
[0041] Furthermore, in this process, while fitting the fitting hole 121 onto the bolt head 311, the projection 113 of the sleeve mounting member 11 is inserted into the insertion hole 122 of the bolt mounting member 12. As described above, since the insertion hole 122 is an elongated hole with an angle α between its two ends of 30 degrees or more, even if the rotational position of the fitting hole 121 and the bolt head 311 is adjusted, the projection 113 can be inserted into the insertion hole 122 without any problems.
[0042] Next, as shown in Figures 10 and 11, the tip portion of the projection 113 that protrudes from the insertion hole 122 of the bolt mounting member 12 is bent radially outward using a tool such as pliers. This prevents the bolt mounting member 12 from falling out of the sleeve mounting member 11 and ensures that the bolt mounting member 12 and the sleeve mounting member 11 are securely connected. Through the above steps, as shown in Figure 5, the installation of the one-sided bolt 30 to the fastened material 50 is completed, and the structure to prevent the one-sided bolt 30 from falling off is also completed. Furthermore, by bending the projection 113 back to its original position, the bolt mounting member 12, bolt 31, and sleeve mounting member 11 can be easily removed.
[0043] In the anti-loosening device 10 of this embodiment, the relative rotation of the sleeve mounting member 11 and the sleeve 32 around the central axis is restricted by the side plate portion 112. Therefore, if the sleeve 32 attempts to rotate in one direction, the sleeve mounting member 11 will also attempt to rotate in the same direction. On the other hand, the fitting hole 121 fits onto the bolt head 311, restricting the relative rotation of the bolt mounting member 12 and the bolt 31 around the central axis. Therefore, if the bolt 31 attempts to rotate in one direction, the bolt mounting member 12 will also attempt to rotate in the same direction. Furthermore, the projection 113 of the sleeve mounting member 11 is inserted into the insertion hole 122, restricting the relative rotation of the sleeve mounting member 11 and the bolt mounting member 12 around the central axis. As a result, the bolt 31 cannot rotate freely relative to the sleeve 32, preventing the bolt 31 from falling out of the sleeve 32. In this way, the bolt 31 can be prevented from falling out simply by using the anti-loosening device 10 without processing the fastened material 50. Therefore, a highly versatile anti-loosening structure can be provided. In particular, in this embodiment, the projection 113 is bent while inserted through the insertion hole 122, and the sleeve mounting member 11 and the bolt mounting member 12 are securely connected, thus reliably preventing the bolt 31 from falling out.
[0044] In this embodiment, as shown in Figure 5, the projection piece 113 is inserted into the through hole 122, whose circumferential length is longer than the width of the projection piece 113. Therefore, when the bolt 31 loosens, the bolt 31 can rotate within the range in which the projection piece 113 can move along the circumferential direction of the through hole 122. However, even in that case, further rotation is restricted when the projection piece 113 comes into contact with the end of the through hole 122. Thus, with the configuration of this embodiment, it is possible to reliably prevent the bolt 31 from falling out of the sleeve 32 while ensuring ease of installation of the anti-loosening device 10.
[0045] Furthermore, the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. Moreover, the present invention is not limited by the embodiments described above.
[0046] The specific details regarding the shape, number, arrangement, and material of each component of the sleeve mounting member and bolt mounting member are not limited to the above embodiments and can be modified as appropriate. For example, in the sleeve mounting member, the number of side plates may be other than four, or it may be a single continuous member surrounding the entire circumference of the side surface of the sleeve head. Also, the number of projections may be other than two. Furthermore, in the bolt mounting member, the shape of the fitting hole may be a hexagonal hole, and the shape of the through hole may not be an elongated hole that is long in the circumferential direction.
[0047] In the above embodiment, a sleeve in which the sleeve head and sleeve pipe portion are integrally formed was given as an example, but the sleeve head and sleeve pipe portion may be constructed as separate parts. Below, a one-side bolt using a sleeve in which the sleeve head and sleeve pipe portion are constructed as separate parts will be described as a modified example.
[0048] Figure 12 is a perspective view showing the configuration of a modified one-side bolt. As shown in Figure 12, the modified one-sided bolt 130 comprises a bolt 31 and a sleeve 132 through which the bolt 31 is inserted. The sleeve 132 has a sleeve head 1321 and a sleeve tube portion 1322. In this modified example of the sleeve 132, the sleeve head 1321 and the sleeve tube portion 1322 are separate parts. The sleeve tube portion 1322 is provided with a through hole 323 through which a bolt 31 is inserted. The sleeve head 1321 has a hexagonal nut shape and has a top surface 1321a and six side surfaces 1321b. The outer shape of the sleeve head 1321, when viewed from the direction of the central axis C, is a regular hexagon. On the inner surface of the through hole that penetrates the sleeve head 1321, there is a female thread portion 1324 that screws into the male thread portion 1323 provided on the outer circumferential surface of the tip end of the sleeve tube portion 1322. On the inner surface of the sleeve tube portion 1322, on the side of the slit 324 that is closer to the tip, there is a female thread portion 1325 that screws into the male thread portion 312 of the bolt 31.
[0049] In this modified example, the male threaded portion 312 of the bolt 31 and the female threaded portion 1325 of the sleeve pipe portion 1322 are right-hand threads. On the other hand, the male threaded portion 1323 of the sleeve pipe portion 1322 and the female threaded portion 1324 of the sleeve head 1321 are left-hand threads. In other words, the first direction R1 in which the bolt 31 rotates when screwing it into the sleeve pipe portion 1322 and the second direction R2 in which the sleeve head 1321 rotates when screwing it into the sleeve pipe portion 1322 are in opposite directions.
[0050] In this configuration, when attaching the bolt 31 to the sleeve 132, if the bolt 31 is rotated in a first direction R1 around the central axis C while holding the sleeve head 1321 with a tool such as a wrench, the rotational force generated in the sleeve tube portion 1322 coincides with the direction that tightens the sleeve head 1321 to the sleeve tube portion 1322. Therefore, when attaching the bolt 31 to the sleeve 132, the sleeve head 1321 and the sleeve tube portion 1322 tend to rotate in a direction that tightens them more, thus preventing the sleeve head 1321 and the sleeve tube portion 1322 from separating.
[0051] In this modified example, the one-sided bolt 130 has a sleeve head 1321 and a sleeve pipe portion 1322 that are separate components. For example, when the fastening of the fastened object is no longer required, the sleeve head 1321 can be easily separated from the sleeve pipe portion 1322 that opens radially outward. Therefore, it is possible to remove the fastened object without damaging the sleeve head with a drill or the like, unlike with a one-piece sleeve 32.
[0052] Furthermore, when the sleeve mounting member 11 of the fall prevention device 10 is attached to the one-sided bolt 130 of this modified example, if the bolt 31 loosens and rotates in the second direction R2, the bolt mounting member 12 and the sleeve mounting member 11 will attempt to rotate in the second direction R2 when the insertion hole 122 comes into contact with the end of the projection piece 113. At this time, the second direction R2 in which the sleeve mounting member 11 rotates coincides with the direction in which the sleeve head 1321 is tightened against the sleeve pipe portion 1322. Therefore, even if the bolt 31 loosens and rotates, the fastening between the sleeve head 1321 and the sleeve pipe portion 1322 will not loosen and the sleeve head 1321 and the sleeve pipe portion 1322 will not separate. Therefore, even when the anti-loosening device 10 is attached to the one-sided bolt 130 of this modified example, the bolt 31 can be reliably prevented from falling off by securely connecting the sleeve mounting member 11 and the bolt mounting member 12, just as when the anti-loosening device 10 is attached to a sleeve 32 in which the sleeve head 321 and the sleeve pipe portion 322 are integrated, as in the above embodiment. [Explanation of Symbols]
[0053] 10... Anti-loosening device for one-sided bolts, 11... Sleeve mounting member, 12... Bolt mounting member, 30, 130... One-sided bolt, 31... Bolt, 32, 132... Sleeve, 111... Top plate, 112... Side plate, 113... Projection, 121... Fitting hole, 121c... Recess, 122... Through hole, 311... Bolt head, 321, 1321... Sleeve head, 321a, 1321a... Top surface, 321b, 1321b... Side surface, C... Central axis.
Claims
1. A one-sided bolt anti-loosening device for a one-sided bolt, comprising a bolt having a bolt head and a sleeve having a sleeve head, which prevents the bolt from falling out of the sleeve, A sleeve mounting member attached to the sleeve head, A bolt mounting member attached to the bolt head, Equipped with, The aforementioned sleeve mounting member is The top plate portion facing the top surface of the sleeve head, A side plate portion extends from the top plate portion along the side surface of the sleeve head portion and restricts the relative rotation between the sleeve and the sleeve mounting member with respect to the central axis of the bolt, It has a projection extending from the top plate portion in a direction different from the extending direction of the side plate portion, The bolt mounting member is A fitting hole that fits into the bolt head and restricts the relative rotation between the bolt and the bolt mounting member with respect to the central axis, A fall prevention device for a one-sided bolt, having an insertion hole through which the projection of the sleeve mounting member is inserted.
2. The one-sided bolt fall prevention device according to claim 1, wherein the projection is bendable while inserted into the insertion hole of the bolt mounting member.
3. The sleeve head is hexagonal prism-shaped, The side plate portion is provided along four of the six sides, the anti-fall device for one-side bolts according to claim 1 or claim 2.
4. The anti-dropping device for a one-side bolt according to claim 3, wherein the width of the top plate portion in the direction perpendicular to the two edges of the top plate portion where the side plate portion is not provided is substantially equal to the width of the sleeve head portion in the direction perpendicular to the two sides of the sleeve head portion which are parallel to each other.
5. The bolt head is hexagonal prism-shaped, The anti-dropping device for one-sided bolts according to claim 1 or claim 2, wherein the fitting hole is a dodecagonal hole having 12 recesses, each of which can be fitted with any one corner of the bolt head.
6. The aforementioned through hole is an elongated hole that extends circumferentially when viewed from the central axis direction, The anti-dropping device for one-side bolts according to claim 5, wherein the angle between the two circumferential ends of the elongated hole with respect to the central axis is 30 degrees or more.