Nut locking device

Abstract

The bolt's male thread can be attached and detached solely by human hands. [Solution] The nut locking device 1 includes a coil spring 11 that can be screwed onto the male thread 102 of the bolt 101, and has a first operating part 31A continuous with one end of the coil spring 11 and a second operating part 31B continuous with the other end. The two operating parts 31A and B each include a pair of finger grips 32 that protrude radially outward from the outer circumference of the coil spring 11. When installing the locking device 1, place your fingers on the pair of finger grips 32 located on the tip side of the male thread 102 and screw it onto the male thread 102 until it abuts against the nut 111. The locking device 1 is fixed in that position and prevents the nut 111 from loosening. When removing the locking device 1, pinch the pair of finger grips 32 that are in contact with the nut 111 with your fingers and rotate them while pushing them in a direction that brings their tips closer together.

Description

Technical Field

[0001] The present disclosure relates to a nut locking device.

Background Art

[0002] As technical means for preventing loosening of a nut screwed onto a bolt, various methods are known. One of them is a method in which a ring-shaped member having spring properties, such as a coil spring, is attached to a male screw.

[0003] Patent Document 1 discloses a locking member that "when fastening a fastened component 40 by screwing a nut 30 onto a male screw 21 such as a bolt 20, is a locking member that is mounted in contact with the upper surface of the nut 30 to prevent loosening of the screw, and is formed in a spiral shape by a wire elastic body 11 so as to be screwed into the screw groove 22 of the male screw 21..." (see paragraph 0005 of Document 1, FIG. 1).

[0004] Regarding such a locking member, after being attached to a bolt, a situation where it should be removed, for example, for maintenance, is assumed. However, Patent Document 1 does not have any special description regarding removing the locking member from the bolt.

[0005] In this regard, Patent Document 2 discloses an anti-drop-off device for a nut in which "a bent portion 12 formed at the tip portion 10A of the coil spring portion 11..." is provided, and an insertion portion 14 is formed in the bent portion so that "a protruding portion 22 of the mounting jig 20 fits therein..." (see paragraphs 0032 and 0034 of Document 2, FIGS. 1 to 6).

[0006] This anti-drop-off device for a nut can be attached to a bolt by "fitting the protruding portion 22 into the insertion portion 14 and rotating it clockwise (in the X direction in FIGS. 5 and 6)..." (see paragraph 0038 of Document 2), and can be removed from the bolt by "fitting the protruding portion 22 of the mounting jig 20 into the insertion portion 14 and rotating it counterclockwise (in the Y direction in the figure)..." (see paragraph 0039 of Document 2).

[0007] As an example described in Patent Document 2, there are precedents for attaching and detaching nut loosening prevention devices to bolts using mounting jigs, such as the detachment prevention devices described in Patent Documents 3 and 4.

[0008] Patent Document 3 discloses a fall prevention device that has knobs (31, 32) at both ends of a coil spring with 1 to 3 turns, and allows the knobs to be gripped with a common tool such as pliers, enabling attachment and detachment to a bolt with minimal force (see paragraphs 0009-0011, 0017, and Figure 4 of Document 3).

[0009] Patent Document 4 teaches how to assist in attaching and detaching a bolt retention device using a socket (S) that can be connected to a tool such as a socket wrench (see paragraphs 0017-0019 and Figures 3-8 of Document 4). [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2000-179525 [Patent Document 2] Japanese Patent Publication No. 2011-027178 [Patent Document 3] Japanese Patent Publication No. 2023-120993 [Patent Document 4] Japanese Patent Publication No. 2024-167538 [Patent Document 5] Japanese Patent Publication No. 2009-052648 [Overview of the project] [Problems that the invention aims to solve]

[0011] As mentioned above, with the anti-loosening member described in Patent Document 1, it is unclear how to remove the anti-loosening member after it has been attached to the male thread of the bolt.

[0012] Patent documents 2 to 4 instruct that the fall prevention device be removed using a special jig or general tools to address this problem, but the work is complicated because a jig or tools are required.

[0013] In contrast, Patent Document 5 discloses a clip-type nut locking device that can be attached to and detached from the male thread of a bolt by human hands alone, without the need for jigs or tools. Paragraph 0017 of this document states, "...the outer pressing portion 13 and the inner pressing portion 14 are pressed together, for example, by an index finger and thumb (not shown), in the direction of the arrows, so that they are close to each other" (see also Figure 1 of Document 5).

[0014] The nut locking device described in Patent Document 5 differs from the coil spring structure shown in Patent Documents 1 to 4 in that it is a clip type. However, even with a coil spring structure nut locking device, if it can be attached to and detached from the male thread of a bolt by human hands alone, work efficiency can be improved.

[0015] The objective of this disclosure is to provide a nut locking device that can be attached to and detached from a bolt's male thread solely by manual labor. [Means for solving the problem]

[0016] One embodiment of a nut locking device comprises a coil spring that can be screwed onto the male thread of a bolt to be attached, a first operating portion wound continuously in the same direction at one end of the coil spring, and a second operating portion wound continuously in the same direction at the other end of the coil spring, wherein each of the first and second operating portions has a pair of finger grips that project radially outward from the outer circumference of the coil spring in a direction symmetrical with respect to a line perpendicular to the axis of the coil spring. [Effects of the Invention]

[0017] If you pinch the pair of finger hooks on the side that contacts the nut with your fingers and press them so that the tip ends of each other are close to each other, the tightening force on the male thread will be loosened and it will be possible to remove it. Therefore, only by manual operation of a person, the nut locking device can be attached to and detached from the male thread of the bolt, and the workability can be improved.

Brief Description of the Drawings

[0018] [Figure 1] Perspective view showing an embodiment of a nut locking device (hereinafter simply referred to as "locking device"). [Figure 2] Its plan view. [Figure 3] Its bottom view (rotated 120 degrees clockwise). [Figure 4] Its front view. [Figure 5] Its rear view. [Figure 6] Its right side view. [Figure 7] Its left side view. [Figure 8] Schematic diagram showing the dimensions of each part. [Figure 9] (A) is a plan view of the locking device showing the shape, angle, and dimensions of each part, and (B) is a plan view of the locking device showing the circumferential deviation angle between the finger hooks of the first operating part and the second operating part. [Figure 10] Exploded perspective view conceptually showing the mounting process of the nut and the locking device on the male thread of the bolt. [Figure 11] Perspective view showing the locking device mounted on the male thread of the bolt and locking the nut. [Figure 12] As the mounting state of the locking device on the male thread of the bolt, (A) shows an appropriate mounting state where it is fully screwed in, and (B) shows an inappropriate mounting state where insufficient screwing has occurred.

Embodiments for Carrying Out the Invention

[0019] The embodiments will be described based on the drawings. The description will be made along the following items. 1. Structure (1) Overview (2) Dimensional relationships of each part (3) Detailed shape of the operating section (4) Relationship between the first operating section and the second operating section 2. Effects (1) Basic effects (i) Installation of anti-loosening devices (b) Removal of locking mechanism (h) Summary (2) Proper installation of anti-loosening devices (i) Visual sign function (b) Proper fit (3) Symmetry (i) Symmetry of each operating part (b) Symmetry between the first operating section and the second operating section (4) Two functions of the finger rest (5) Wearability (6) Removability (7) Portability (8)Durability 3. Variant

[0020] 1. Structure (1) Overview As shown in Figures 1 to 7, the nut locking device 1 of this embodiment (hereinafter simply referred to as "locking device 1") includes a coil spring 11 that can be screwed onto the male thread 102 of the bolt 101 which is the object to be attached. A first operating part 31A is provided on one end of the coil spring 11, and a second operating part 31B is provided on the other end.

[0021] The coil spring 11 constitutes the tightening portion 12, which tightens the male thread 102 of the bolt 101. In this embodiment, we introduce a loosening prevention device 1 that is compatible with a bolt 101 having a right-hand thread 102, where the tightening direction is to the right (clockwise). Therefore, the coil spring 11 that forms the tightening portion 12 also has a right-handed spiral shape that is wound in a clockwise direction.

[0022] As shown in Figure 10, when attaching a right-handed coil spring 11 to a right-handed male thread 102, rotating it clockwise causes the coil spring 11 to advance toward the bolt head 103 and screw into the male thread 102. Conversely, rotating the coil spring 11 counterclockwise causes it to move away from the bolt head 103 and can be removed from the male thread 102.

[0023] In another embodiment, to accommodate a bolt 101 having a left-hand threaded male thread 102 with a left-hand tightening direction (counterclockwise), a coil spring 11 having a left-handed spiral shape wound in a counterclockwise direction can be used as the tightening portion 12.

[0024] The number of turns of the coil spring 11 is, for example, two turns. However, in practice, the number of turns of the coil spring 11 is not limited to this, and it may be one turn or three or more turns.

[0025] The first operating section 31A is continuous with one end of the coil spring 11 and is wound in the same direction as the coil spring 11. In Figures 1 and 4-7, the first operating section 31A is located at the top.

[0026] The second operating section 31B is continuous with the other end of the coil spring 11 and is wound in the same direction as the coil spring 11. In Figures 1 and 4-7, the second operating section 31B is located at the bottom.

[0027] In this embodiment, the first operating section 31A and the second operating section 31B are not distinguished and may be referred to simply as "operating section." In this case, they are written as "operating section 31A, B." When referring to either the first operating section 31A or the second operating section 31B, they are written as "operating section 31A or 31B."

[0028] The operating sections 31A and B each have a pair of finger rests 32. These finger rests 32 have a shape that protrudes radially outward from the outer circumference of the coil spring 11 in a direction symmetrical with respect to a hypothetical line perpendicular to the axis A of the coil spring 11.

[0029] The pair of finger rests 32, when viewed individually, have a shape that follows the equilateral EQ of an isosceles triangle IT (see Figure 9(A)). The overall shape of the operating sections 31A and B, including the pair of finger rests 32, has the shape of a parallelogram PR as its basic form (see Figure 9(A)). This point will be discussed later in the section "(3) Detailed shape of the operating section".

[0030] The anti-loosening device 1 of this embodiment is constructed from a single stainless steel spring wire 51, comprising a coil spring 11 that constitutes the tightening portion 12, and operating portions 31A and B equipped with a pair of finger rests 32. At this time, the stainless steel spring wire 51 has an end 51E (see Figure 2) on the side of the first operating portion 31A and an end 51E (see Figure 3) on the side of the second operating portion 31B. As shown in Figure 1, these ends 51E of the stainless steel spring wire 51 are in contact with other parts of the stainless steel spring wire 51 and are closed without leaving any gaps between them.

[0031] For example, SUS304 is used as the stainless steel wire 51 for springs. SUS304 is classified in both "JIS G 4313 Stainless steel strip for springs" and "JIS G 4313 Stainless steel wire for springs," and is a representative material among stainless steels used for springs. Of course, in practice, it is possible to use not only SUS304, but also all kinds of stainless steels for springs such as SUS301, SUS316, and SUS316-WPA.

[0032] (2) Dimensional relationships of each part Figure 8 schematically shows the anti-loosening device 1 to clearly illustrate the dimensions of each part. The male thread 102 of the bolt 101 has an outer diameter (nominal diameter) of D1 and a root diameter of D2.

[0033] The anti-loosening device 1 has an inner diameter of coil spring 11 as D11, and the shortest inner length of the operating parts 31A and B is DL. Length DL is the length of the shorter diagonal SD of the parallelogram PR that forms the basic shape of the operating parts 31A and B (see Figure 9(A)). The shape of the operating parts 31A and B and diagonal D will be explained in the next section, "(3) Detailed shape of the operating parts".

[0034] As shown in Figure 8, in this embodiment, the inner diameter D11 of the coil spring 11 is set to be smaller than the outer diameter D1 of the bolt 101 and larger than the root diameter D2. The length DL of the shorter diagonal SD of the operating parts 31A and B is set to be shorter than the outer diameter D1 of the bolt 101 and longer than the root diameter D2. Furthermore, the length DL of the shorter diagonal SD of the operating parts 31A and B is set to be longer than the inner diameter D11 of the coil spring 11.

[0035] To summarize the above, Outer diameter D1 > Diagonal length SD DL > Inner diameter D11 > Root diameter D2 This is the result.

[0036] (3) Detailed shape of the operating section Figure 9(A) is a plan view of the anti-loosening device 1 showing the shape, angles, and dimensions of each part. In this embodiment, the pair of finger rests 32 provided on the operating parts 31A and B are symmetrical with respect to a hypothetical plane passing through the axis A of the coil spring 11.

[0037] More specifically, the pair of finger rests 32 have a shape that forms the equilateral side EQ of an isosceles triangle IT, where each rests symmetrically with respect to a hypothetical line perpendicular to the axis A of the coil spring 11, and each rests symmetrically with respect to the vertex V of the isosceles triangle IT. In this case, the vertex angle α1 of the isosceles triangle IT is set to, for example, 70°. Needless to say, the vertex angle α1 is not limited to 70°, but may be an angle between 60° and 80°, or any other angle.

[0038] The pair of finger rests 32 have a curved shape at a position corresponding to the vertex V, which is the tip of each, and the portions forming equilateral EQ each have the same size and shape.

[0039] Observing from a different perspective, the operating sections 31A and B have the basic shape of a parallelogram PR. This parallelogram PR has two diagonals D of different lengths, with a short diagonal SD and a long diagonal LD.

[0040] The parallelogram PR, when viewed from the axial direction of the coil spring 11 (direction of axis A), has a shape in which the length DL of the shorter diagonal SD is greater than the inner diameter D11 of the coil spring 11. Here, the length DL of the diagonal SD refers to the length of the inner region of the operating parts 31A and B, which are formed by the spring stainless steel wire 51.

[0041] In the operating sections 31A and B, the positions corresponding to the two pairs of opposite vertices VV of the parallelogram PR have a curved shape.

[0042] (4) Relationship between the first operating section and the second operating section The first operating section 31A and the second operating section 31B are identical in size and shape.

[0043] As described above, the anti-loosening device 1 of this embodiment is constructed entirely from a single stainless steel spring wire 51, and the operating parts 31A and B are both wound in the same direction as the right-handed coil spring 11, which is wound in a clockwise direction.

[0044] As shown in Figure 2, the finger rest 32 of the first operating part 31A is positioned such that the end 51E of the spring stainless steel wire 51 is located on the left side of Figure 2, approaching from above along the extension of the shorter diagonal SD of the parallelogram PR (see Figure 9(A)). The spring stainless steel wire 51 is wound clockwise starting from the position of the end 51E shown in Figure 2, and constitutes the anti-loosening device 1.

[0045] As shown in Figure 3, the finger rest 32 of the second operating part 31B is positioned so that the end 51E of the spring stainless steel wire 51 is on the right side in Figure 3, approaching from below along the extension of the shorter diagonal SD of the parallelogram PR (see Figure 9(A)). The spring stainless steel wire 51 is wound clockwise starting from the position of the end 51E shown in Figure 3, forming the anti-loosening device 1. However, the bottom view of Figure 3 is rotated 120 degrees clockwise from the plan view shown in Figure 2 to show the anti-loosening device 1 for clarity.

[0046] As is clear from Figures 2 and 3, the anti-loosening device 1 has a right-handed spiral shape, wound clockwise, whether viewed from the side of the first operating part 31A or the side of the second operating part 31B. Therefore, it can be screwed onto the male thread 102 of the bolt 101 in the same way from either the side of the first operating part 31A or the second operating part 31B. In other words, the anti-loosening device 1 of this embodiment has no front or back orientation, and can be screwed onto the male thread 102 in the same way from either side.

[0047] Figure 9(B) shows the circumferential offset angle set between the finger rests 32 of the first operating section 31A and the second operating section 31B. The finger rests 32 of the first operating section 31A and the second operating section 31B are offset by an angle α2 so that they do not overlap each other in the circumferential direction of the coil spring 11. The angle α2 is, for example, 45°. Of course, the angle α2 is not limited to 45°, but may be an angle between 20° and 70°, or any other angle.

[0048] 2. Effects (1) Basic effects The bolt 101 and nut 111 (see Figure 10) are used, for example, to fasten two members (not shown). As an example, through holes (not shown) provided in two members are aligned, and the male thread 102 of the bolt 101 is inserted into these through holes. Then, the nut 111 is screwed onto the male thread 102 protruding from the through hole and tightened, thereby fastening the two members between the bolt head 103 and the nut 111.

[0049] As shown in Figures 10 and 11, in this embodiment, when a nut 111 is screwed onto a male screw 102, and two members (not shown) to be fixed are sandwiched between the bolt head 103 and the nut 111, the dimensions of each part are set such that when the nut 111 is tightened, the tip of the male screw 102 protrudes from the nut 111, creating an excess. The anti-loosening device 1 is attached to the excess portion that protrudes from the tip of the male screw 102.

[0050] (i) Installation of anti-loosening devices To attach the locking device 1 to the male screw 102, press either the operating part 31A or 31B against the end of the male screw 102 and rotate the locking device 1 clockwise. At this time, place your fingers on the pair of finger rests 32 on the operating part 31A or 31B that is furthest from the bolt head 103 and screw in the locking device 1.

[0051] Figure 12 is a plan view showing the state in which the anti-loosening device 1 is attached to the male thread 102 of the bolt 101. When the anti-loosening device 1 is screwed in, the operating part 31A or 31B on the side closer to the bolt head 103 abuts against the nut 111. From this state, the anti-loosening device 1 is screwed in further to the state shown in Figure 12(A). At this time, the operating part 31A or 31B that abuts against the nut 111 does not rotate due to frictional resistance between it and the nut 111, and only the operating part 31A or 31B on the opposite side rotates. The rotated operating part 31A or 31B tries to return to its original angle due to the elastic restoring force of the coil spring 11, but the force tightening the male thread 102 resists it and it does not return to its original angle.

[0052] Therefore, with one of the operating parts 31A or 31B of the anti-loosening device 1 abutting against the nut 111, the coil spring 11 tightens the male screw 102, fixing it in this position and preventing the nut 111 from loosening.

[0053] (b) Removal of locking mechanism To remove the locking device 1 from the male screw 102, the pair of finger rests 32 included in the operating part 31A or 31B that contacts the nut 111 are pinched between the fingers and pushed toward each other. The position where the fingers are placed is the tip of the finger rest 32, that is, the position corresponding to vertex V of the isosceles triangle IT shown in Figure 9(A). The tip of the finger rest 32 protrudes outward from the outer wall surface of the nut 111, making it easy to place the fingers and push it in. The spring stainless steel wire 51 has a curved shape at that position, so it is soft against the fingers.

[0054] When the pair of finger rests 32 are gripped and pressed with the fingers in this manner, the tips of the pair of finger rests 32 are displaced in a direction that brings them closer together. As a result, the stainless steel spring wire 51 deforms in the operating section 31A or 31B such that the length DL of the shorter diagonal SD of the parallelogram PR (see Figure 9(A)) that forms the basic shape of the operating sections 31A and 31B becomes longer. This deformation of the stainless steel spring wire 51 also extends to the coil spring 11, and the inner diameter D11 of the coil spring 11 gradually increases from the side of the operating section 31A or 31B on which the length DL of the diagonal SD has increased. This loosens the tightening force of the coil spring 11 and the operating section 31A or 31B on the male thread 102 of the bolt 101, making it possible to rotate the locking device 1 in the direction of detachment (counterclockwise). By rotating the locking device 1 in this direction, it can be removed from the male thread 102.

[0055] (h) Summary As described above, the anti-loosening device 1 of this embodiment can be attached to and detached from the male thread 102 of the bolt 101 solely by manual labor, without the use of jigs or tools. Therefore, work efficiency can be improved.

[0056] (2) Proper installation of anti-loosening devices (i) Visual sign function As shown in Figure 12(A), in this embodiment, when the angle α2 (see Figure 9(B)), which is the angle difference between the first operating part 31A and the second operating part 31B, is approximately 90°, the anti-loosening device 1 is properly screwed into the male thread 102 of the bolt 101. In other words, this state is when the same diagonals D (SD, LD) of each operating part 31A and B are perpendicular to each other in the parallelogram PR (see Figure 9(A)) that forms the basic shape of the operating parts 31A and B.

[0057] Figure 12(A) shows the proper mounting state in which the anti-loosening device 1 is fully screwed onto the male screw 102. At this time, the pair of finger rests 32 included in the first operating section 31A and the pair of finger rests 32 included in the second operating section 31B form a shape that crosses at equal angles.

[0058] In contrast, Figure 12(B) shows an improper mounting condition when the locking device 1 is not screwed in sufficiently. The pair of finger rests 32 included in the first operating section 31A and the pair of finger rests 32 included in the second operating section 31B do not form a shape that crosses at equal angles.

[0059] As shown in Figures 12(A) and 12(B), the angle α2 visually appears as a cross shape of the pair of finger rests 32 included in the first operating section 31A and the second operating section 31B, respectively. By visually observing this cross shape of the finger rests 32, the operator can easily recognize and confirm whether the anti-loosening device 1 is properly attached.

[0060] Therefore, according to this embodiment, the pair of finger rests 32 included in the first operating section 31A and the second operating section 31B can be provided with a visual indicator function to show whether the anti-loosening device 1 is properly installed, thereby facilitating confirmation by the operator.

[0061] (b) Proper fit As mentioned above, when the angle α2 (see Figure 9(B)), which is the angle difference between the first operating part 31A and the second operating part 31B, is approximately 90°, the locking device 1 is in the proper state, fully screwed in. So, what exactly constitutes the proper state? This point will be explained.

[0062] When angle α2 becomes 90°, if we let the initial angle of angle α2 be x, then the operating part 31A or 31B on the screw tip side of the male screw 102 is relative to the operating part 31A or 31B that is in contact with the nut 111. y = 90° - x This means it has rotated clockwise by α². y is the angle of increase of angle α².

[0063] For example, if the initial angle x of angle α2 is 45°, then the increase in angle y will be 45°. If the initial angle x of angle α2 is 30°, then the increase in angle y will be 60°. And if the initial angle x of angle α2 is 70°, then the increase in angle y will be 20°. Thus, the increase in angle y of angle α2 depends on the initial angle x of angle α2.

[0064] The important point here is that the increase in angle α2 affects the tightening force of the coil spring 11 on the male screw 102. An increase in angle α2 from the initial angle means that the operating part 31A or 31B on the screw end side of the male screw 102 rotates clockwise relative to the operating part 31A or 31B that is in contact with the nut 111, so the winding of the stainless steel spring wire 51 loosens from the side of the operating part 31A or 31B on the screw end side. More specifically, the length DL of the diagonal SD gradually expands at the operating part 31A or 31B on the screw end side, and the inner diameter D11 of the coil spring 11 also gradually widens.

[0065] Therefore, the larger the angle α2 becomes, that is, the more the operating part 31A or 31B on the threaded end side of the male screw 102 is rotated clockwise relative to the operating part 31A or 31B that is in contact with the nut 111, the less the tightening force of the coil spring 11 and the operating part 31A or 31B on the male screw 102 of the bolt 101 becomes.

[0066] On the other hand, the operating part 31A or 31B on the tip side of the male screw 102 and the coil spring 11 attempt to return to the initial angle α2 due to their elastic restoring force, but the force tightening the male screw 102 resists this, and it does not return to the initial angle. The operating part 31A or 31B on the tip side of the screw is fixed in the position rotated clockwise, and the male screw 102 is tightened.

[0067] The basic performance required of the anti-loosening device 1 in this embodiment is to stably maintain the state of being fixed to the male thread 102 of the bolt 101 over a long period of time and to reliably prevent the nut 111 from loosening. At the same time, ease of installation and removal by hand is also required. The tightening force on the male thread 102 must be determined from the perspective of achieving these potentially contradictory and complex requirements at a high level.

[0068] Factors that influence the strength of the tightening force on the male screw 102 include: (a) Angle of the increase in angle α2 In addition, (b) Inner diameter D11 of coil spring 11 (c) The difference between the outer diameter D1 of the male screw 102 and the inner diameter D11 of the coil spring 11. (d) Length of the short diagonal SD DL (e) The difference between the outer diameter D1 of the male screw 102 and the length DL of the short diagonal SD (f) Rigidity and elastic force of the stainless steel wire 51 for springs These include (see Figure 8).

[0069] When determining the angle y that increases the angle α2, the relationship with other elements such as elements (b) to (f) must be taken into comprehensive consideration. The angle y that increases the angle α2, determined by such comprehensive judgment, constitutes the "appropriate state" in which the aforementioned anti-loosening device 1 is fully screwed in.

[0070] Once the angle y representing the increase in angle α2 is determined in this way, the angle α2 when the anti-loosening device 1 is attached to the male screw 102 should be 90°, for example, x = 90° - y Using this formula, the initial angle x of angle α2 can be easily determined.

[0071] In this embodiment, the initial setting angle α2 is exemplified as 45°, a range between 20° and 70°, or other angles. These various angles are exemplified as angles that constitute an "appropriate state" in which the anti-loosening device 1 is sufficiently screwed into the male screw 102.

[0072] (3) Symmetry (i) Symmetry of each operating part The pair of finger rests 32 are symmetrical with respect to a hypothetical plane passing through the axis A of the coil spring 11. More specifically, the pair of finger rests 32 have a shape that forms the equilateral side EQ of an isosceles triangle IT, where the vertices V are positioned symmetrically with respect to a line perpendicular to the axis A of the coil spring 11 (see Figure 9(A)). From another perspective, the operating parts 31A and B have the shape of a parallelogram PR, where the length DL of the shorter diagonal SD is longer than the inner diameter D11 of the coil spring 11, when viewed from the axial direction of the coil spring 11 (direction of axis A).

[0073] Since the first operating section 31A and the second operating section 31B each have the symmetrical shape described above, there is no directionality between the pair of finger rests 32, which improves workability when attaching and detaching the bolt 101 to the male thread 102.

[0074] Furthermore, the fact that the first operating section 31A and the second operating section 31B have symmetrical shapes, combined with the fact that the anti-loosening device 1 is manufactured by bending the spring stainless steel wire 51, leads to rationalization of manufacturing.

[0075] (b) Symmetry between the first operating section and the second operating section The first operating section 31A and the second operating section 31B are identical in size and shape.

[0076] Therefore, the anti-loosening device 1 has no front or back orientation, and can be screwed onto the male thread 102 in the same way from either the first operating part 31A or the second operating part 31B. Thus, inconveniences such as incorrect access direction of the bolt 101 to the male thread 102 can be avoided, and workability can be improved.

[0077] Furthermore, the fact that the first operating section 31A and the second operating section 31B are the same size and shape, combined with the fact that the anti-loosening device 1 is manufactured by bending the spring stainless steel wire 51, leads to rationalization of manufacturing.

[0078] (4) Two functions of the finger rest The symmetry between the first operating section 31A and the second operating section 31B gives the operating sections 31A and B two different functions. Two examples will be used to illustrate this.

[0079] In the first example, we assume a case where the locking device 1 is screwed into the male thread 102 of the bolt 101 by accessing it from the side of the second operating part 31B. At this time, the pair of finger rests 32 included in the first operating part 31A function as finger rests to assist in the work of screwing in the locking device 1. Subsequently, when removing the locking device 1, the pair of finger rests 32 included in the second operating part 31B that are in contact with the nut 111 are pushed in a direction that brings their tips closer together, so these pair of finger rests 32 function as operating parts to weaken the tightening force.

[0080] In the second example, conversely, we consider a case where the locking device 1 is screwed into the male thread 102 of the bolt 101 by accessing it from the side of the first operating part 31A. In this case, the pair of finger rests 32 included in the second operating part 31B function as finger rests to assist in the work of screwing in the locking device 1. Subsequently, when removing the locking device 1, the pair of finger rests 32 included in the first operating part 31A that are in contact with the nut 111 are pushed in a direction that brings their tips closer together, so these pair of finger rests 32 function as operating parts to weaken the tightening force.

[0081] When referring to the two examples above, focusing on the function of the locking mechanism 1 as a finger rest to assist in the screwing process, in the first example, the pair of finger rests 32 included in the first operating part 31A perform this function, and in the second example, the pair of finger rests 32 included in the second operating part 31B perform this function. When focusing on the function of the operating part to reduce the tightening force, in the first example, the pair of finger rests 32 included in the second operating part 31B perform this function, and in the second example, the pair of finger rests 32 included in the first operating part 31A perform this function.

[0082] Therefore, according to this embodiment, each of the pair of finger rests 32 included in the two operating parts 31A and B is equipped with both the function of a finger rest to assist in screwing in the locking device 1 and the function of an operating part to reduce the tightening force, thereby simplifying the structure and consequently reducing the weight of the product.

[0083] (5) Wearability As shown in Figure 8, the length DL of the shorter diagonal SD of the operating parts 31A and B is longer than the inner diameter D11 of the coil spring 11. This makes the initial screwing operation of the bolt 101 into the male thread 102 easier, and improves the ease of attaching the anti-loosening device 1.

[0084] (6) Removability To remove the locking device 1 from the male thread 102 of the bolt 101, as described above, the pair of finger rests 32 provided on the operating part 31A or 31B that contacts the nut 111 are pushed with the fingers in a direction that brings their tips closer together. At this time, the finger rests 32 have a curved shape at the part corresponding to vertex V of the isosceles triangle IT shown in Figure 9(A), so the contact with the fingers is soft, and good removal is obtained.

[0085] The shape of the pair of finger rests 32 depends on the size of the vertex angle α1 of the isosceles triangle IT. When the vertex angle α1 is large, the tip of the finger rest 32 becomes gentler, and the amount that protrudes radially outward from the coil spring 11 decreases. Conversely, when the vertex angle α1 is small, the tip of the finger rest 32 becomes steeper, and the amount that protrudes radially outward from the coil spring 11 increases.

[0086] If the shape of the finger rests 32 is too steep, the pressure on the fingers will be too strong when the pair of finger rests 32 are pressed in. On the other hand, if the amount that protrudes radially outward from the coil spring 11 is too small, the fingers will interfere with the nut 111 when the pair of finger rests 32 are pressed together, and a sufficient amount of pressing will not be achieved. Therefore, the size of the apex angle α1 is set appropriately, taking into account the degree of pressure on the fingers when the pair of finger rests 32 are pressed in and the degree of interference with the nut 111.

[0087] (7) Portability The end 51E of the spring stainless steel wire 51 that constitutes the anti-loosening device 1 is in contact with the other part of the spring stainless steel wire 51, and is closed without leaving a gap between it and the other part. Therefore, even when multiple anti-loosening devices 1 are stored together, it is possible to prevent the anti-loosening devices 1 from becoming entangled with each other, and thus improve portability.

[0088] (8)Durability Nuts screwed onto bolts can loosen and fall off due to vibrations transmitted by factors such as wind, passing vehicles, and foot traffic. These vibrations, caused by various factors, are also transmitted to the nut's locking mechanism, causing it to resonate. This resonance then acts as a load, leading to damage to the locking mechanism, a phenomenon that has been observed.

[0089] Based on the observation that breakage occurs in the portion where the spring stainless steel wire is sharply bent, the anti-loosening device 1 of this embodiment is designed to prevent breakage of the spring stainless steel wire 51 that constitutes the anti-loosening device 1 by giving a curved shape to the portion corresponding to opposite vertices VV of the parallelogram PR, particularly the portion corresponding to vertex V of the isosceles triangle IT.

[0090] Therefore, the anti-loosening device 1 of this embodiment has high durability.

[0091] 3. Variant Various modifications and changes are possible during implementation.

[0092] For example, the clamping portion 12 with the coil spring 11 may be configured to have the coil spring 11 in only a portion of it. The same applies to the operating portions 31A and B; for example, the finger rest portion 32 may be fitted with a component other than the stainless steel spring wire 51.

[0093] In this embodiment, the coil spring 11, the first operating part 31A, and the second operating part 31B are constructed from a single stainless steel spring wire 51. However, the structure is not limited to this configuration in practice. These three elements may be constructed by joining together separate components.

[0094] The shape of the finger rests 32, which are included in the operating sections 31A and B, is not limited to a shape that follows the equilateral side EQ of the isosceles triangle IT, but can be made into various shapes, such as a quadrilateral or a trapezoid.

[0095] Furthermore, any modifications or changes are possible during implementation. [Explanation of symbols]

[0096] 1. Nut locking device 11 Coil spring 12. Fastening part 31A First operating section 31B Second operating section 32 Finger rest 51 Stainless steel wire for springs 51E End 101 volts 102 Male screw 103 Bolt Head 111 Nut A axis center D1 Outer diameter D2 Valley diameter D11 Inner Diameter DL (Short diagonal length) Equal-sided EQ IT isosceles triangle D Diagonal LD (Long diagonal) PR Parallelogram SD Short diagonal V vertex VV opposite vertices α1 vertical angle α2 angle

Claims

1. A coil spring that can be screwed onto the male thread of the bolt to be attached, A first operating section, which is wound continuously in the same direction around one end of the coil spring, A second operating section, which is wound continuously in the same direction around the other end of the coil spring, Equipped with, Each of the first and second operating parts has a pair of finger rests that project radially outward from the outer circumference of the coil spring in a direction symmetrical with respect to a line perpendicular to the axis of the coil spring. A device to prevent nuts from loosening.

2. The finger rests of the first and second operating parts are offset from each other in the circumferential direction of the coil spring so as not to overlap. A nut locking device according to claim 1.

3. The circumferential displacement angle of the finger rests between the first and second operating parts is between 20° and 70°. The nut locking device according to claim 2.

4. The pair of finger rests are symmetrical with respect to a plane passing through the axis of the coil spring. A nut locking device according to claim 1.

5. The pair of finger rests have the shape of equal sides of an isosceles triangle, with each vertex positioned symmetrically with respect to a line perpendicular to the axis of the coil spring. A nut locking device according to claim 1.

6. The pair of finger rests have a curved shape at a position corresponding to the apex. The nut locking device according to claim 5.

7. The vertex angle of the aforementioned isosceles triangle is set to an angle between 60° and 80°. The nut locking device according to claim 6.

8. The first operating section and the second operating section each have the same size and shape. The nut locking device according to claim 5.

9. The first and second operating parts have a parallelogram shape, when viewed from the axial direction of the coil spring, such that the length of the shorter diagonal is longer than the inner diameter of the coil spring. A nut locking device according to claim 1.

10. The first and second operating sections have a curved shape at positions corresponding to two pairs of vertices of the parallelogram. The nut locking device according to claim 9.

11. The coil spring and the first and second operating parts are made from a single stainless steel spring wire. A nut locking device according to any one of claims 1 to 10.

12. The end of the aforementioned stainless steel wire for the spring is closed in contact with the other part. The nut locking device according to claim 11.

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