Fall prevention device

Abstract

To provide a falling prevention tool capable of being screwed in using a tool until it contacts a nut, and capable of being reliably and easily attached.SOLUTION: A falling prevention device comprises: a first coil spring part composed of a coil wire wound in a predetermined direction; a second coil spring part having one end connected to one end of the coil wire constituting the first coil spring part, and composed of the coil wire wound in an approximately circular shape in the same direction as a predetermined direction; and a third coil spring part having one end connected to the other end of the coil wire constituting the second coil spring part, and composed of a coil wire wound in the same direction as the predetermined direction. Both the first and third coil spring parts are polygonal in shape with a plurality of apex parts located at approximately the same distance from each other from the winding center of the second coil spring part, and diameters of circumscribed circles of the first to third coil spring parts increase in the order of the second, third, and first coil spring parts.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fall prevention device that prevents a bolt from falling off. [Background technology]

[0002] Generally, methods for fastening two components that make up a building structure are either welding or fastening with bolts and nuts. Fastening by welding requires equipment such as gas cylinders and burners, and is time-consuming and labor-intensive, so fastening with bolts and nuts is more commonly used. When fastening with bolts and nuts, the fastened nuts can become loose due to vibrations, etc., so fall prevention devices have been proposed to prevent the nuts from loosening.

[0003] For example, Patent Documents 1 and 2 propose inventions for a fall-off prevention device that includes: a first coil spring portion made up of a coil wire wound in a predetermined direction; a second coil spring portion having one end connected to one end of the coil wire making up the first coil spring portion, made up of a coil wire wound in the same direction as the predetermined direction and having a diameter smaller than the inscribed circle of the first coil spring portion; and a third coil spring portion having one end connected to the other end opposite to the one end of the coil wire of the second coil spring portion connected to one end of the coil wire of the first coil spring portion, made up of a coil wire wound in the same direction as the predetermined direction and having an inscribed circle larger than the diameter of the second coil spring portion. The fall-off prevention devices described in Patent Documents 1 and 2 have a second coil spring portion that is threaded onto a bolt to prevent the nut or the object to be fixed from loosening. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2011 / 145212 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-156482 Summary of the Invention [Problem to be solved by the invention]

[0005] In the captive devices described in Patent Documents 1 and 2, the diameters of the circumscribed circles of the first and third coil spring portions are equal. Therefore, when the captive devices described in Patent Documents 1 and 2 are installed using a socket wrench, the captive device can sometimes be pushed all the way into the socket. When the captive device is screwed onto the bolt in this state, the tip of the socket comes into contact with the nut, preventing the captive device from being screwed in any further. The captive device must then be tightened by hand until it comes into contact with the nut. Furthermore, there have been cases where the installer did not notice that the captive device and the nut were not in contact, resulting in an incomplete installation. An object of the present invention is to provide a fall-off prevention device that can be screwed in using a tool until it contacts a nut and that can be easily and reliably attached. [Means for solving the problem]

[0006] The means for solving the problems of the present invention are as follows. 1. A first coil spring portion composed of a coil wire wound in a predetermined direction; a second coil spring portion having one end connected to one end of the coil wire constituting the first coil spring portion and configured with a coil wire wound in a substantially circular shape in the same direction as the predetermined direction; a third coil spring portion having one end connected to the other end of the coil wire constituting the second coil spring portion and configured with a coil wire wound in the same direction as the predetermined direction; and Both the first and third coil spring portions have a polygonal shape with a plurality of apexes disposed at substantially the same distance from the winding center of the second coil spring portion, A fall-off prevention device characterized in that the diameters of the circumscribed circles of the first to third coil spring portions increase in the order of the second, third, and first. 2. A fall prevention device as described in 1., characterized in that either the other end of the first coil spring portion or the other end of the third coil spring portion, or both, are located between the coil wire constituting the first coil spring portion and the coil wire constituting the third coil spring portion. 3. The fall-off prevention device according to 1. or 2., characterized in that the first coil spring portion and the third coil spring portion are wound in any one of a trigon to a dodecagon. [Effects of the Invention]

[0007] In the capsulation device of the present invention, the diameter of the circumscribed circle of one (first) coil spring portion is larger than the diameter of the circumscribed circle of the other (third) coil spring portion, and when the smaller (third) coil spring portion is fitted into the socket, the larger (first) coil spring portion does not fit into the socket. The capsulation device of the present invention can be securely attached until it contacts the nut using only a tool such as a socket wrench, which provides excellent workability and significantly reduces the effort required for attachment. Because the capsulation device of the present invention can be securely attached using only a tool, attachment time can be shortened. Capsulation devices are used in large quantities on steel towers, bridges, etc., so using the capsulation device of the present invention can shorten the construction period. [Brief explanation of the drawings]

[0008] [Figure 1] 1A is a view of the fall-off prevention device of the first embodiment as seen from the axial direction, and FIG. 1B is a view of the fall-off prevention device of the first embodiment as seen from the radial direction (the direction of the black arrow in FIG. 1A). [Figure 2] 1 is a photographed image of a fall prevention device according to a first embodiment. [Figure 3] 10A and 10B are diagrams showing how the fall-off prevention device of the first embodiment is fitted into the socket. [Figure 4] FIG. 2 is a diagram showing the state in which the fall-off prevention device of the first embodiment is fitted into the socket. [Figure 5] 10 is a photograph of the fall-off prevention device of the first embodiment fitted into a socket. [Figure 6] 4A to 4C are diagrams for explaining a method of attaching the fall-off prevention device of the first embodiment. [Figure 7]4A to 4C are diagrams for explaining a method of attaching the fall-off prevention device of the first embodiment. [Figure 8] 4A to 4C are diagrams for explaining a method of attaching the fall-off prevention device of the first embodiment. [Figure 9] FIG. 2 is a diagram showing the state in which the fall-off prevention device of the first embodiment is attached to a bolt. DETAILED DESCRIPTION OF THE INVENTION

[0009] In this specification, the axial direction and radial direction refer to the axial direction and radial direction of the bolt shank when the fall-off prevention device of the present invention is attached to the bolt shank. Furthermore, the expression "A to B" (A and B are numerical values) refers to a numerical range including both ends, i.e., A or more and B or less. The fall-off prevention device of the present invention will be described below with reference to the drawings. A view of a fall-off prevention device 10 according to a first embodiment of the present invention as viewed from the axial direction (A) and radial direction (B) is shown in Fig. 1, and a photographed image is shown in Fig. 2. Fig. 1(A) is a view as viewed from the third coil spring portion side, and Fig. 1(B) is a view as viewed from the direction of the black arrow in Fig. 1(A).

[0010] The first embodiment of the fall-off prevention device 10 is as follows: a first coil spring portion 1 formed of a coil wire wound in a substantially hexagonal shape; a second coil spring portion 2 having one end connected to one end of the coil wire constituting the first coil spring portion 1 and configured with a coil wire wound in a substantially circular shape in the same direction; The third coil spring portion 3 has one end connected to the other end of the second coil spring portion 2 and is made of a coil wire wound in a substantially hexagonal shape in the same direction.

[0011] The fall-off prevention device 10 is formed from a coil wire having a circular cross-sectional shape. In the fall-off prevention device of the present invention, the cross-sectional shape of the coil wire is not particularly limited, and for example, a steel wire having an approximately circular or approximately rectangular cross-sectional shape can be used. It is preferable to use a steel wire or round steel having an approximately circular cross-sectional shape for the coil wire, because the coil wire and the thread groove do not come into contact at corners, the coil wire fits easily into the thread groove, and it is less likely to wear. The approximately circular shape is not limited to a circle (a perfect circle), but may also be an ellipse or an egg shape. The outer diameter of the coil wire may be large enough to fit into the thread groove of a bolt. In other words, it may be a diameter that can contact both sides of the thread groove of the bolt, and it is preferable that the diameter be 20 to 80% of the depth of the thread groove, and more preferably 30 to 70%.

[0012] The fall prevention device 10 is wound in a direction that fits from the leg of the bolt toward the head of the bolt when turned clockwise. The fall prevention device 10 is wound in only one direction without being folded back in the axial direction, making it easy to manufacture. In the fall-off prevention device 10, the first and third coil spring parts 1 and 3 are generally hexagonal in shape, but are generally regular hexagons in which all apexes of both hexagons are located at substantially the same distance from the center of winding of the second coil spring part 2. In this specification, the shape of the coil spring part means the shape as viewed from the axial direction. In the fall-off prevention device of the present invention, the first and third coil spring portions 1, 3 may have any shape that allows them to be fitted into a socket, and may be, for example, a trigonal to dodecagonal shape, but the polygonal shape is not limited to a regular polygon. The shapes of the first and third coil spring portions are preferably trigonal, hexagonal, or dodecagonal, and more preferably regular hexagonal or regular dodecagonal, so that they can be fitted into commonly used sockets. Furthermore, the shapes of the first and third coil spring portions may be the same polygon (similar shapes) or different polygons.

[0013] The capsulation prevention device 10 is attached to the bolt by screwing the second coil spring portion 2 onto the bolt shank. There is no particular limit to the number of turns of the second coil spring portion 2, but 2 turns or more is preferable, 2.5 turns or more is more preferable, and 3 turns or more is even more preferable. The longer the number of turns, the greater the contact area between the capsulation prevention device and the bolt, increasing friction and improving capsulation prevention. There is no upper limit to the number of turns, but as the capsulation prevention device becomes bulky as the number of turns increases, 5 turns or less is preferable, 4.5 turns or less is more preferable, 4 turns or less is even more preferable, and 3.5 turns or less is even more preferable.

[0014] The second coil spring portion 2 has an inner diameter that is slightly smaller than the outer diameter of the bolt leg to which it is attached, but larger than the diameter of the circle formed by the bottom of the thread groove, at least excluding one end thereof on the first coil spring portion 1 side. The second coil spring portion 2 is formed so that the radius of curvature gradually increases at one end thereof on the first coil spring portion 1 side. The captive device 10 is formed so that the diameter of the portion that is first threaded onto the bolt (the first coil spring portion 1 side of the second coil spring portion 2) is slightly larger, allowing it to be threaded onto the bolt with little force at the beginning, resulting in excellent workability. Furthermore, since the diameter of the portion that is first threaded onto the bolt is slightly larger, the end of the thread groove (the tip of the bolt) and the second coil spring portion 2 easily fit together, making it easy to attach to the bolt regardless of differences in the diameter of the bolt leg or the position of the end of the thread groove. The portion where the radius of curvature is large is preferably 1 / 4 turn or more and 1 turn or less, more preferably 2 / 4 turn or more, and even more preferably 3 / 4 turn or more.

[0015] In the anti-drop device, the radius of curvature of the other end side, which is the side of the third coil spring portion 3 of the second coil spring portion 2, may be the same as the radius of curvature of most of the region of the second coil spring portion 2, or may gradually increase toward the other end. When both ends of the second coil spring portion 2 are formed so that the radius of curvature increases, when the bolt is mounted, both ends of the second coil spring portion 2 are separated from the thread groove and slightly float. And when the anti-drop device is mounted on the bolt and both ends of the second coil spring portion float from the thread groove, the floating portion is deformable in the radial direction, so that the spring elasticity is exhibited. And due to this spring elasticity, the impact from the nut or the fixed object is absorbed and attenuated. Therefore, the anti-drop device of the present invention is less likely to cause metal fatigue and can prevent breakage even when a force is applied due to vibration or the like.

[0016] As shown in Fig. 1(B), for the anti-drop device 10, when the diameters of the circumscribed circles of the first to third coil spring portions 1, 2, and 3 are R1, R2, and R3 respectively, the diameters of the circumscribed circles are in the order of the second, third, and first being larger, that is, R2 < R3 < R1 is satisfied. Preferably, R3 is 1.02 times or more of R2, more preferably 1.04 times or more, further preferably 1.06 times or more, even more preferably 1.08 times or more, and even more preferably 1.1 times or more. Preferably, R1 is 1.02 times or more of R3, more preferably 1.04 times or more, further preferably 1.06 times or more, even more preferably 1.08 times or more, and even more preferably 1.1 times or more.

[0017] · Method of attaching the anti-drop device The method of attaching the anti-drop device 10, which is the first embodiment, will be described in order while using the drawings. The anti-drop device 10 is fitted into the socket S from the side of the third coil spring portion 3 (Fig. 3). Since the anti-drop device 10 satisfies R3 < R1, when the third coil spring 3 is fitted into the socket S, the first coil spring portion 1 does not enter the inside of the socket S (Figs. 4 and 5). Although the third coil spring portion has a polygonal shape, it is preferable that its diameter can be fitted into a socket corresponding to a hexagonal nut defined in JIS B1181:2014 because it can be attached using a general-purpose socket.

[0018] Using a tool such as a socket wrench (not shown), the fall-off prevention device 10 fitted into the socket S is screwed onto the bolt shaft B and attached (FIGS. 6 and 7). The socket is rotated with a predetermined torque to screw the captive device 10 onto the bolt shank B. Because the first coil spring portion 1 of the captive device 10 is not fitted into the socket S, it can be securely attached using only a tool until the first coil spring portion 1 contacts the nut N (Figs. 8 and 9).

[0019] How to remove the fall prevention device The attached fall prevention device 10 can be removed by using a socket that matches the size of the first coil spring portion 1 and rotating it in the opposite direction to that used for attachment. The first coil spring portion 1 has a polygonal shape, but it is preferable that its diameter be able to fit into a socket that corresponds to a hexagonal nut specified in JIS B1181:2014, so that it can be removed using a general-purpose socket.

[0020] Other Embodiments The fall-off prevention device of the present invention is not limited to the first embodiment described above. For example, either or both of the first coil spring portion and the third coil spring portion can be wound around the second coil spring portion 2 so as to be folded back (see Figures 1 and 2 of Patent Document 2). By configuring it in this way, the fall-off prevention device can be made more compact. [Explanation of symbols]

[0021] 10 Fall prevention device 1 First coil spring part 2 Second coil spring part 3 Third coil spring part S socket B Bolt shaft N nut

Claims

1. a first coil spring portion formed of a coil wire wound in a predetermined direction; a second coil spring portion having one end connected to one end of the coil wire constituting the first coil spring portion, the second coil spring portion being constituted by a coil wire wound in a substantially circular shape in the same direction as the predetermined direction; a third coil spring portion having one end connected to the other end of the coil wire constituting the second coil spring portion, the third coil spring portion being constituted by a coil wire wound in the same direction as the predetermined direction; and Both the first and third coil spring portions have polygonal shapes with a plurality of apexes disposed at substantially the same distance from the winding center of the second coil spring portion, the diameters of the circumscribed circles of the first to third coil spring portions increase in the order of the second, third, and first; A fall-off prevention device characterized in that the first and third coil spring portions are both mountable to sockets corresponding to hexagonal nuts specified in JIS B1181:2014.

2. The fall prevention device according to claim 1, characterized in that either the other end of the first coil spring portion or the other end of the third coil spring portion, or both, are located between the coil wire constituting the first coil spring portion and the coil wire constituting the third coil spring portion.

3. 3. The fall-off prevention device according to claim 1, wherein the first coil spring portion and the third coil spring portion are wound in any one of a trigon to a dodecagon.

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