Fall prevention device

Abstract

To provide a falling prevention tool capable of being mounted easily, and hard to come off from a bolt or nut.SOLUTION: A falling prevention tool 1 prevents a bolt or nut from falling out. The falling prevention tool 1 has an annular part 2 that is press-fitted onto a screw part of the bolt.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fall-off prevention device that prevents a nut threaded onto a bolt from falling off, and also prevents a bolt inserted into a bolt hole from falling out of the bolt hole. [Background technology]

[0002] For example, there is a known support bracket for a suspension bolt that supports and secures various steel materials, such as channel material, at the intermediate position of a suspension bolt suspended from a ceiling slab or the like. These brackets, bolts, and nuts are packaged separately, and must be temporarily assembled at the work site before being attached to the suspension bolt, which does not provide very high work efficiency. Therefore, from the standpoint of work efficiency, it is preferable to ship the brackets in a so-called temporarily assembled state, in which the nuts are loosely screwed onto the bolts, and then perform only the assembly work at the work site from the temporarily assembled state. However, it is difficult to prevent situations where the nuts fall off the bolts due to vibrations during delivery, causing the temporarily assembled state to fall apart.

[0003] Various nut locking devices have existed in the past, and it may be possible to reuse them for temporary assembly (see Patent Documents 1 and 2). However, most nut locking devices have a coil spring shape and must be inserted by screwing in from the bottom end of the bolt after the bolt and nut have been tightened. This makes installation less convenient, and they cannot be used in situations where there is no gap below the bolt that is larger than the spring length, making them less user-friendly for temporary assembly. Furthermore, because they are manufactured by bending steel wire, it is difficult to reduce the cost, and they do not offer excellent cost performance. Furthermore, the tip of the wire is hooked onto the side of the nut to prevent the nut from rotating, which creates the problem of it easily coming off the nut. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-203316 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-333005 Summary of the Invention [Problem to be solved by the invention]

[0005] The purpose is to provide a fall prevention tool that can be easily attached and is difficult to come off from bolts and nuts. [Means for solving the problem]

[0006] The fall-off prevention tool according to this embodiment, which prevents a bolt or a nut from falling off, has a circular ring portion that is press-fitted onto the threaded portion of the bolt. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a fall-off prevention device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the fall-off prevention device of FIG. [Figure 3] 3 is a cross-sectional view taken along the line AA in FIG. 2. [Figure 4] FIG. 2 is a side view of the fall-off prevention device of FIG. [Figure 5] 1A is a side view showing how the fall prevention device of FIG. 1 is attached to a bolt and a hexagonal nut, FIG. 1B is a side view showing the state in which the guide piece of the fall prevention device is in contact with the threaded portion of the bolt, and FIG. 1C is a bottom view showing how the annular portion of the fall prevention device expands in diameter. [Figure 6] 2A is a development view showing the state in which the fall-off prevention device of FIG. 1 is attached to a bolt and a hexagonal nut, (b) is a perspective view showing the state in which the fall-off prevention device of (a) is attached to a bolt and a hexagonal nut, (c) is a side view of (b), and (d) is a bottom view of (b). [Figure 7] 2 is a diagram showing how the fall-off prevention device of FIG. 1 is turned over and attached to a bolt and a hexagonal nut. FIG. [Figure 8]8(a) is a development view showing the state in which the fall-off prevention device of FIG. 7 is attached to a bolt and a hexagonal nut, (b) is a perspective view showing the state in which the fall-off prevention device of (a) is attached to a bolt and a hexagonal nut, (c) is a side view of (b), and (d) is a bottom view of (b). [Figure 9] FIG. 10 is a perspective view showing a fall-off prevention device according to a second embodiment of the present invention. [Figure 10] FIG. 10 is a plan view of the fall-off prevention device of FIG. 9. [Figure 11] 11 is a cross-sectional view taken along the line AA in FIG. 10. [Figure 12] FIG. 10 is a side view of the fall-off prevention device of FIG. 9. [Figure 13] 10 is a diagram showing how the fall-off prevention tool of FIG. 9 is attached to a bolt and a plate nut. FIG. [Figure 14] 10(a) is a development view showing the state in which the fall-off prevention device of FIG. 9 is attached to a bolt and a plate nut, and FIG. 10(b) is a side view showing the state in which the fall-off prevention device is attached to a bolt and a plate nut. [Figure 15] FIG. 10 is a perspective view showing a modified example of the fall-off prevention device according to the second embodiment. [Figure 16] FIG. 10 is a perspective view showing another modified example of the fall-off prevention device according to the second embodiment. [Figure 17] FIG. 10 is a perspective view showing yet another modified example of the fall-off prevention device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, a fall-off prevention device according to this embodiment will be described with reference to the drawings. In the following description, components having the same functions and configurations are given the same reference numerals, and repeated description will be given only when necessary. (First embodiment) Figures 1 to 4 show a fall prevention device according to this embodiment. Figure 5 shows how the fall prevention device is attached to a bolt and a nut, and Figure 6 shows the fall prevention device attached to the bolt and the nut. Note that, although an example in which the fall prevention device 1 according to this embodiment is adapted to a hexagonal nut 30 will be described below, it can also be adapted to other types of square nuts, such as square nuts.

[0009] The fall prevention device 1 prevents the nut 30 threaded onto the bolt 20 from falling off, and also prevents the bolt 20 inserted into a bolt hole drilled in a metal fitting or the like from slipping out of the bolt hole. The fall prevention device 1 is an integral resin molded body made of a resin typically having high abrasion resistance and high elasticity, such as polyacetal (POM), polyamide (PA), or polycarbonate (PC). The fall prevention device 1 has a circular ring portion 2, to the outer periphery of which is bonded a rectangular plate-shaped abutment portion 4. The circular ring portion 2 has an arc-shaped notch 300° in an angle of less than 180°, typically between 20° and 30°, and the abutment portion 4 is located on the opposite side of the notch 3, 180° in the circumferential direction of the circular ring portion 2. An operator can grasp the abutment portion 4 and push the circular ring portion 2 through the notch 3 onto the bolt 20.

[0010] The inner diameter W0 of the annular portion 2 is configured to be slightly shorter than the outer diameter (diameter) of the threaded portion 22 of the bolt 20 to be attached. As a result, the annular portion 2 is press-fitted onto the threaded portion 22 of the bolt 20, and clamps the threaded portion 22 by its elasticity.

[0011] The height H1 of the abutting portion 4 is configured to be longer than the thickness T1 of the annular portion 2, and the bottom surface of the abutting portion 4 is aligned with the bottom surface of the annular portion 2. In a side view, the abutting portion 4 protrudes along the center line C relative to the annular portion 2. The abutting portion 4 is disposed parallel to the center line C of the annular portion 2 and parallel to the tangent to the inner circle of the annular portion 2. The inner surface of the abutting portion 4 is disposed away from the center line C of the annular portion 2 by a distance substantially equivalent to half the width across flats of the hexagonal nut 30, which serves as the object to be prevented from falling off and is threaded onto the bolt 20. As a result, when the annular portion 2 is press-fitted onto the threaded portion 22 of the bolt 20, the inner surface of the abutting portion 4 abuts against one side surface 33 of the hexagonal nut 30, preventing the hexagonal nut 30 from freely rotating relative to the bolt 20.

[0012] Typically, the width W2 of the abutting portion 4 is configured to be shorter than the outer diameter W1 of the annular portion 2. This minimizes interference with the wrench and surrounding area when attaching the fall-off prevention device 1 to the bolt 20 and hexagonal nut 30, when tightening the bolt 20 with a wrench, and when fixing the hexagonal nut 30. However, it is not prohibited to configure the width W2 of the abutting portion 4 to be longer than or equivalent to the outer diameter W1 of the annular portion 2.

[0013] A pair of guide pieces 5 are provided at both ends of the annular portion 2 where the notches 3 are formed, in a direction that spreads outward. When the inner surfaces of the guide pieces 5 are placed in contact with the outer circumferential surface of the threaded portion 22 of the bolt 20 and the bolt is pressed in, the inner surfaces of the guide pieces 5 move along the outer circumferential surface of the threaded portion 22 of the bolt 20, thereby expanding the diameter of the annular portion 2 and allowing it to be easily fitted onto the threaded portion 22 of the bolt 20.

[0014] A pair of filamentary projections 6 that engage with the thread roots of the bolt 20 are provided on the opposing inner surfaces of the annular portion 2. In order to minimize interference with the pushing movement when the annular portion 2 is pushed through its notch 3 into the threaded portion 22 of the bolt 20, the filamentary projections 6 are provided along the front-to-rear center line connecting the center of the notch 3 with the center of a recess 7, described below, on the inner surface on the opposite side. With the annular portion 2 press-fitted onto the threaded portion 22 of the bolt 20, the filamentary projections 6 engage with the thread roots of the bolt 20, preventing displacement of the fall-out prevention device 1 relative to the bolt 20. Furthermore, because the linear projections 6 on the inner surface of the annular portion 2 engage with the thread root of the bolt 20 in the same way as the hexagonal nut 30, when the rotation of the hexagonal nut 30 is fixed with a tightening tool such as a spanner or wrench and the bolt 20 is strongly rotated around its axis to tighten, the annular portion 2 moves along the axial direction of the threaded portion 22 of the bolt 20 together with the hexagonal nut 30, and the fall-off prevention device 1 does not interfere with the tightening of the hexagonal nut 30. The same is true when loosening the hexagonal nut 30 from the bolt 20.

[0015] An arc-shaped recess 7 is provided on the inner surface of the annular portion 2 opposite the cutout 3, which disperses the stress that accompanies the expansion of the annular portion 2 and prevents the annular portion 2 from breaking due to stress concentration.

[0016] The fall prevention device 1 is attached to the bolt 20 and the hexagonal nut 30 after the object to be fastened has been tightened between the bolt 20 and the hexagonal nut 30, or in a temporary assembly state in which the hexagonal nut 30 is loosely screwed onto the bolt 20.

[0017] As shown in Figure 5(a), the captive device 1 is placed below the hexagonal nut 30 when viewed from the head 21 of the bolt 20. That is, the upper surface of the annular portion 2 is in contact with the underside of the hexagonal nut 30 threaded onto the bolt 20, and the captive device 1 is placed in an orientation in which the abutment portion 4 protrudes upward (toward the head 21 of the bolt 20) relative to the annular portion 2. The captive device 1 is then brought horizontally close to the threaded portion 22 of the bolt 20 from the side. As shown in Figures 5(b) and 5(c), the inner surface of the guide piece 5 is placed against the outer periphery of the threaded portion 22 of the bolt 20, and the annular portion 2 is pressed firmly in this state, causing the annular portion 2 to expand on both sides due to its elasticity and receive the threaded portion 22. The annular portion 2 contracts in diameter due to its elasticity, clamping the threaded portion 22. As shown in Figures 6(a), 6(b), 6(c), and 6(d), the inner surface of the part of the abutment portion 4 protruding from the annular portion 2 abuts against one side surface 33 of the hexagonal nut 30.

[0018] Because the annular portion 2 clamps the threaded portion 22, the captive device 1 is fixed to the bolt 20. Furthermore, because the abutting portion 4 abuts against one side surface 33 of the hexagonal nut 30, rotation of the hexagonal nut 30 relative to the captive device 1 is prevented. Therefore, rotation of the hexagonal nut 30 relative to the bolt 20 and rotation of the bolt 20 relative to the hexagonal nut 30 are suppressed via the captive device 1, so even if the hexagonal nut 30 is loosely threaded onto the bolt 20, the hexagonal nut 30 is prevented from coming off the bolt 20. Furthermore, when the bolt 20 is inserted into a bolt hole of a metal fitting or the like and threaded onto the hexagonal nut 30, the captive device 1 can be prevented from hitting the periphery of the bolt hole and causing the bolt 20 to fall out of the bolt hole. Furthermore, even if there is no nut, attaching the captive device 1 to the bolt 20 can prevent the bolt 20 from falling out of the bolt hole.

[0019] The annular portion 2 holds the threaded portion 22 and the linear projections 6 engage with the thread roots of the threaded portion 22, so that the fall-off prevention tool 1 does not shift position relative to the bolt 20, and the abutting portion 4 is in surface contact with one side surface 33 of the hexagonal nut 30, so that the fall-off prevention tool 1 is unlikely to come off the hexagonal nut 30.

[0020] Furthermore, because the fall prevention device 1 can be attached to the side of the bolt 20, the attachment is easier than inserting it from the bottom end (tip) of the bolt 20. Furthermore, when the bolt 20 and the hexagonal nut 30 are rotated relative to each other to tighten or loosen the bolt 20, the fall prevention device 1 moves along the axial direction of the threaded portion 22 of the bolt 20 together with the hexagonal nut 30, so the tightening or loosening work of the bolt 20 and the hexagonal nut 30 is not hindered, and the fall prevention device 1 is not damaged by tightening, making it suitable for repeated use.

[0021] The fall-off prevention device 1 can be manufactured as an integral resin molding, which provides excellent cost performance. However, this does not deny that the fall-off prevention device 1 can be made of a metal that also has elasticity.

[0022] In this way, the fall prevention device 1 is suitable for temporary assembly of bolts 20, hex nuts 30, metal fittings, etc., and can be shipped in a temporary assembled state, so that at the work site, only assembly work can be performed from the temporary assembled state, thereby improving work efficiency.

[0023] In the above description, the captive device 1 is attached to the underside of the hexagonal nut 30 as viewed from the head 21 of the bolt 20. However, as shown in FIGS. 7 and 8, the captive device 1 can also be attached in the opposite direction. That is, as shown in FIG. 7, the captive device 1 is positioned so that the underside of the annular portion 2 contacts the upper surface of the hexagonal nut 30 threaded onto the bolt 20, and the abutting portion 4 protrudes downward from the annular portion 2. The captive device 1 is then brought horizontally close to the threaded portion 22 of the bolt 20 from the side. As shown in FIGS. 8(a), 8(b), 8(c), and 8(d), the inner surface of the abutting portion 4 protruding downward from the annular portion 2 abuts against one side surface 33 of the hexagonal nut 30. The same effect can be achieved even when the captive device 1 is attached in the opposite direction. In this case, although there is a possibility that the captive device 1 may be damaged by tightening, the tightened hexagonal nut 30 can be prevented from loosening.

[0024] In the above explanation, the abutment portion 4 is described as protruding in one direction relative to the annular portion 2 when viewed from the side, but the abutment portion 4 may also be configured to protrude in both upward and downward directions relative to the annular portion 2 when viewed from the side. (Second embodiment) Figures 9 to 12 show a fall prevention device 10 according to this embodiment. Figure 13 shows how the fall prevention device 10 is attached to the bolt 20 and plate nut 40, and Figure 14 shows the fall prevention device 10 attached to the bolt 20 and plate nut 40. The fall prevention device 10 is fitted to a groove-shaped plate nut 40 in which a steel plate is bent into a U-shape in cross section. The plate nut 40 consists of a rectangular bottom plate 41 and a pair of side plates 43, and a screw hole 42 that screws onto the bolt 20 is formed in the center of the bottom plate 41.

[0025] The difference between the fall-off prevention device 10 according to the second embodiment and the fall-off prevention device 1 according to the first embodiment described above is the abutting portion 14. Since the rest of the device is the same as the fall-off prevention device 1 according to the first embodiment except for the abutting portion 14, a description thereof will be omitted.

[0026] The abutting portion 14 of the fall-off prevention device 10 according to this embodiment has the same thickness as the thickness T1 of the annular portion 2, and is configured flat with no steps above or below the annular portion 2. The outer diameter W1 of the annular portion 2 is configured to be shorter than the distance between the pair of side plates 43 of the plate nut 40 to be attached.

[0027] The width W3 of the abutting portion 14 is configured to be longer than the outer diameter W1 of the annular portion 2, and in a plan view, both ends of the abutting portion 14 protrude to the left and right beyond the annular portion 2. The width W3 of the abutting portion 14 is appropriately designed to be equal to or slightly shorter than the distance between the pair of side plates 43 of the plate nut 40 to be attached.

[0028] 13 , with plate nut 40 threaded onto bolt 20, captive device 10 is placed between bottom plate 41 and the upper edge of side plate 43 of plate nut 40, and is brought close to the threaded portion 22 of bolt 20 from the side, in a position horizontal to bottom plate 41. While inserting captive device 10 into the gap between the pair of side plates 43 of plate nut 40, the annular portion 2 is pressed firmly onto the threaded portion 22 of bolt 20, and captive device 10 is attached to bolt 20 and plate nut 40.

[0029] 14(a) and 14(b), the fall-off prevention device 10 is fitted inside the plate nut 40, and both ends of the abutting portion 14 abut against the inner surfaces of the pair of side plates 43 of the plate nut 40. Because the annular portion 2 holds the threaded portion 22 and both ends of the abutting portion 14 abut against the inner surfaces of the pair of side plates 43 of the plate nut 40, rotation of the plate nut 40 relative to the bolt 20 and rotation of the bolt 20 relative to the plate nut 40 are suppressed, thereby preventing the plate nut 40 from falling off the bolt 20 and also preventing the bolt 20 from coming loose from the plate nut 40.

[0030] This embodiment also has the same effects as the first embodiment.

[0031] In the above description, the abutment portion is described as being coupled to the annular portion at a position opposite the cutout, but this is not limited to this. For convenience of explanation, the cutout 3 is defined as the front of the annular portion 2, and the recess 7 is defined as the rear of the annular portion 2. As shown in FIG. 15 , the abutment portion 14 may be coupled to either the left or right side of the annular portion 2. In other words, the abutment portion 14 is coupled to the annular portion 2 between the position of the cutout 3 and a position opposite the cutout 3.

[0032] 16, a pair of abutment portions 15 as abutment portion 14 may be joined to annular portion 2 so as to extend to both left and right edges of notch 3 of annular portion 2 and protrude to the left and right from annular portion 2. Furthermore, as shown in FIG. 17, a pair of abutment portions 16 may be joined to both left and right side portions of annular portion 2.

[0033] Of course, the same applies to the abutment portion 4 in the first embodiment; the abutment portion 4 may be attached to either the left or right side of the annular portion 2, or the pair of abutment portions forming the abutment portion 4 may be attached to the annular portion 2 so as to extend to both left and right sides of both edges of the cutout 3, or the pair of abutment portions may be attached to both left and right sides of the annular portion 2.

[0034] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0035] 1...anti-fall-off device, 2...annular portion, 3...notch, 4...contact portion, 5...guide piece, 6...linear protrusion, 7...recess.

Claims

1. In a fall prevention device that prevents a bolt or nut from falling off, a circular ring portion press-fitted onto the threaded portion of the bolt; a contact portion coupled to the annular portion and contacting the nut to lock the rotation of the nut relative to the bolt, The width of the contact portion is greater than the outer diameter of the annular portion. Falling prevention device.

2. 2. The fall-off prevention device according to claim 1, wherein the annular portion has a notch formed in a part thereof, and is inserted from the side onto the outer peripheral surface of the threaded portion of the bolt.

3. The fall-off prevention device according to claim 2 , wherein the abutting portion is coupled to the annular portion at a position opposite to the notch.

4. An anti-fall-off device as described in claim 2, wherein the abutment portion is connected to the annular portion between the position of the notch and a position opposite the notch.

5. An anti-fall-off device as described in claim 2, wherein the abutment portion consists of a pair of abutment parts respectively joined to both edges of the cutout.

6. The fall-off prevention device according to claim 1 , wherein the contact portion has a plate shape with a height greater than a thickness of the annular portion.

7. The nut is a square nut, The fall-off prevention device according to claim 6, wherein the abutment portion has a plate shape longer than a thickness of the annular portion and abuts against one side of the square nut to prevent rotation of the square nut relative to the bolt.

8. The nut is a plate nut, 2. The fall prevention device according to claim 1, wherein both ends of the abutment portion, which has a width greater than the outer diameter of the annular portion, abut against the inner surfaces of a pair of side plates of the plate nut, thereby preventing the plate nut from rotating relative to the bolt.

9. In a fall prevention device that prevents a bolt or nut from falling off, a circular ring portion press-fitted onto the threaded portion of the bolt; a contact portion coupled to the annular portion and contacting the nut to lock the rotation of the nut relative to the bolt, A notch is formed in a part of the annular portion, and the annular portion is inserted from the side into the outer peripheral surface of the threaded portion of the bolt, The abutment portion is coupled to the annular portion between the position of the notch and a position on the opposite side of the notch. Falling prevention device.

10. In a fall prevention device that prevents a bolt or nut from falling off, a circular ring portion press-fitted onto the threaded portion of the bolt; a contact portion coupled to the annular portion and contacting the nut to lock the rotation of the nut relative to the bolt, A notch is formed in a part of the annular portion, and the annular portion is inserted from the side into the outer peripheral surface of the threaded portion of the bolt, The abutment portion is composed of a pair of abutment portions respectively coupled to both edges of the notch. Falling prevention device.

11. The fall-off prevention device according to claim 9 or 10, wherein the contact portion has a plate shape with a height greater than a thickness of the annular portion.

12. The nut is a square nut, The fall-off prevention device according to claim 11, wherein the abutment portion has a plate shape longer than a thickness of the annular portion and abuts against one side of the square nut to prevent rotation of the square nut relative to the bolt.

13. In a fall prevention device that prevents a bolt or nut from falling off, a circular ring portion press-fitted onto the threaded portion of the bolt; a contact portion coupled to the annular portion and contacting the nut to lock the rotation of the nut relative to the bolt, The nut is a plate nut, The end portions of the abutting portion, which have a width greater than the outer diameter of the annular portion, abut against the inner surfaces of the pair of side plates of the plate nut, thereby suppressing rotation of the plate nut relative to the bolt. Falling prevention device.

14. In a fall prevention device that prevents a bolt or nut from falling off, a circular ring portion press-fitted onto the threaded portion of the bolt; a contact portion coupled to the annular portion and contacting the nut to lock the rotation of the nut relative to the bolt, The nut has a U-shape, The abutment portion abuts against the inner surfaces of the pair of side plates of the nut to suppress rotation of the nut relative to the bolt. Falling prevention device.

15. The fall-off prevention device according to any one of claims 1 to 14, wherein the annular portion and the abutting portion are an integral resin molded body.

16. In a fall prevention device that prevents a bolt or nut from falling off, a circular ring portion press-fitted onto the threaded portion of the bolt; a contact portion coupled to the annular portion and contacting the nut to lock the rotation of the nut relative to the bolt, The annular portion and the abutting portion are an integral resin molded body. Falling prevention device.

17. The fall-off prevention device according to any one of claims 1 to 16, wherein an inner surface of the annular portion is provided with linear projections that mesh with thread roots of the bolt.

18. In a fall prevention device that prevents a bolt or nut from falling off, a circular portion press-fitted onto the threaded portion of the bolt; The inner surface of the annular portion is provided with linear protrusions that mesh with the thread roots of the bolt. Falling prevention device.

19. 19. A fall prevention device according to claim 1, wherein an arc-shaped recess is provided on the inner surface of the annular portion to disperse stress caused by the expansion of the annular portion and prevent breakage due to stress concentration.

Images