Nut locking structure and fixing piece thereof

Abstract

A nut anti-loosening structure and a fixing piece thereof are used for solving the problem that an existing nut can automatically loosen when screwed. At least one end of a screw rod forms an open end, the screw rod is provided with a thread part, and the thread part comprises a first thread screwed in the first direction and a second thread screwed in the second direction. The first screw cap is provided with an internal thread which is screwed into the thread part of the screw rod towards a first direction; the second screw cap is provided with an internal thread which is screwed into the thread part of the screw rod towards a second direction; and the fixing piece is sleeved on the outer walls of the first nut and the second nut through an inner wall, so that the first nut and the second nut cannot independently rotate relative to the screw rod. According to the utility model, the first screw cap and the second screw cap can be prevented from loosening and rotating through the fixing piece.

Description

Technical Field

[0001] The utility model relates to a nut anti-loosening structure, in particular to a structure for preventing a nut from loosening by itself and a fixing piece thereof. Background Art

[0002] Nuts can be used for fastening and are widely used, including in various machinery, equipment, vehicles, ships, railways, bridges, buildings, etc. Existing nuts are screwed on a screw or a bolt in a threaded manner. The thread can be left-handed or right-handed, and the fastened object can be fastened with a single nut or a double nut. In a static state, the nut can achieve the purpose of fastening. That is, under static load, the nut will not loosen or fall off. However, when the fastened object is subjected to variable loads such as impact and vibration, the nut will loosen or fall off by itself.

[0003] Please refer to Figure 1 As shown, it is a patent application of China's publication No. CN 102312899 A that discloses a fastening device with bidirectional threads, including a screw rod 9 with threads at one end, the screw rod 9 is provided with a clockwise thread segment 9a and a counterclockwise thread segment 9b, the counterclockwise thread segment 9b has a smaller diameter than the clockwise thread segment 9a, and two nuts 91 and 92 respectively have corresponding clockwise internal threads and counterclockwise internal threads, so that the two nuts 91 and 92 can be screwed into the clockwise thread segment 9a and the counterclockwise thread segment 9b respectively. A groove 93 is provided on the end face of the positive nut 91 with clockwise internal threads, and a convex block 94 corresponding to the size of the groove 93 is provided on the end face of the reverse nut 92 with counterclockwise internal threads, and the groove 93 and the convex block 94 are engaged and locked to prevent the two nuts 91 and 92 from loosening.

[0004] Since the two nuts 91, 92 are screwed into the clockwise thread section 9a and the counterclockwise thread section 9b of the screw rod 9, the protrusion 94 obviously cannot enter the groove 93 when the counter-clockwise nut 92 rotates. That is, the structure disclosed in the patent case obviously cannot prevent the two nuts 91, 92 from loosening due to vibration during use.

[0005] Please refer to Figure 2As shown, it is a patent application of China published No. CN 108386436 A that discloses an anti-loosening fastener, including a bolt 8, a first nut 81 and a second nut 82. The bolt 8 is composed of a right-handed threaded rod 8a and a left-handed threaded rod 8b. The first nut 81 is matched and connected with the right-handed threaded rod 8a, and the second nut 82 is matched and connected with the left-handed threaded rod 8b. A docking groove 83 is provided on a side of the second nut 82 close to the right-handed threaded rod 8a, and a protruding block 84 is provided on a side of the first nut 81 close to the left-handed threaded rod 8b, and the protruding block 84 is matched with the docking groove 83.

[0006] When in use, use a tool to install the first nut 81 and the right-handed threaded rod 8a of the lower half of the bolt 8, so that the first nut 81 is maintained in the middle section of the bolt 8, and then continue to use a tool to install the second nut 82 and the left-handed threaded rod 8b of the upper half of the bolt 8, and screw the second nut 82 toward the lower half of the bolt 8 to fix the first nut 81, so that the protruding block 84 is slowly screwed into the docking slot 83 under the forced extrusion force, so that the first nut 81 and the second nut 82 are tightly connected. When the set of fasteners is combined, due to the different upper and lower thread directions of the bolt 8, when any one of the first nut 81 and the second nut 82 becomes loose during activity, it will only drive the other nut to rotate tighter and tighter. Because the friction force of the first nut 81 and the second nut 82 is combined into a nearly integrated whole, the positions of the first nut 81 and the second nut 82 will be permanently fixed, thereby achieving the purpose of permanently preventing loosening under variable load conditions.

[0007] Since the anti-loosening fastener needs to have the protruding block 84 on the first nut 81 and the docking slot 83 on the second nut 82, the selection of the first nut 81 and the second nut 82 is limited by the manufacturer, and the manufacturing cost of the first nut 81 and the second nut 82 is relatively high. In particular, the first nut 81 and the second nut 82 will loosen due to vibration during use, and the first nut 81 and the second nut 82 will rotate in different spiral directions due to the different spiral directions of the right-handed threaded rod 8a and the left-handed threaded rod 8b. It is impossible to ensure that when any one of them loosens, it will only drive the other nut to rotate tighter and tighter, but instead cause the first nut 81 and the second nut 82 to rotate in directions away from each other. Therefore, the structure disclosed in the patent application cannot ensure that the first nut 81 and the second nut 82 can be prevented from loosening due to vibration during use.

[0008] Therefore, it is indeed necessary to improve the existing nut anti-loosening structure. Utility Model Content

[0009] In order to solve the above problems, the main purpose of the utility model is to provide a nut anti-loosening structure, which can be used to tighten the fastened object and ensure that the nut will not loosen due to vibration during use.

[0010] A second object of the present invention is to provide a nut anti-loosening structure that can be applied to existing nuts to avoid being restricted by manufacturers and to reduce overall costs.

[0011] Another object of the present invention is to provide a fixing member which can be used to limit the two nuts from rotating independently relative to the screw rod, so as to ensure that the nuts will not become loose due to vibration during use.

[0012] The directions or their approximate terms described throughout the present invention, such as front, back, left, right, top, bottom, inside, outside, side, etc., mainly refer to the directions of the accompanying drawings. Each direction or its approximate terms are only used to assist in the description and understanding of the various embodiments of the present invention, and are not used to limit the present invention.

[0013] The elements and components described throughout the present invention use the quantifiers "one" or "an" only for the convenience of use and to provide a general meaning of the scope of the present invention; in the present invention, they should be interpreted as including one or at least one, and a single concept also includes plural cases, unless it is obvious that it means otherwise.

[0014] The utility model discloses a nut anti-loosening structure, comprising: a screw rod, having a first end and a second end, at least one end of the screw rod forms an open end, the screw rod has a threaded portion, the threaded portion comprises a first thread screwed in a first direction and a second thread screwed in a second direction; a first nut, having an internal thread and an outer wall, the internal thread screwed in the threaded portion of the screw rod in the first direction; a second nut, having an internal thread and an outer wall, the internal thread screwed in the threaded portion of the screw rod in the second direction; and a fixing member, the inner wall of which is sleeved on the outer walls of the first nut and the second nut, so that the first nut and the second nut cannot rotate independently relative to the screw rod.

[0015] The utility model discloses a nut anti-loosening structure, comprising: a screw rod, having a small diameter portion and a large diameter portion adjacent to each other, the small diameter portion having a first threaded portion, the large diameter portion having a second threaded portion, the first threaded portion and the second threaded portion being screwed in opposite directions; a first nut, having an internal thread and an outer wall, the internal thread being screwed into the first threaded portion of the screw rod in a first direction; a second nut, having an internal thread and an outer wall, the internal thread being screwed into the second threaded portion of the screw rod in a second direction; and a fixing member, the inner wall of which is sleeved on the outer walls of the first nut and the second nut, so that the first nut and the second nut cannot rotate independently relative to the screw rod.

[0016] The fixing piece of the utility model is a cylinder body made of plastic or metal material. The cylinder body has an inner wall. The cross-section shape of the inner wall is a regular polygon.

[0017] Therefore, the nut anti-loosening structure and the fixing member of the utility model can be sleeved on the peripheral sides of the first nut and the second nut by the fixing member to limit the first nut and the second nut from rotating independently relative to the screw rod. Furthermore, the first end surface of the screw rod has a first engaging portion, and the top inner surface of the fixing member has a second engaging portion, and the second engaging portion can be engaged with the first engaging portion to form the effect of limiting the first nut and the second nut from rotating synchronously relative to the screw rod.

[0018] The first end of the screw rod forms an open end, the threaded portion is connected to the open end, and the second end of the screw rod has a cap head. Therefore, the screw rod can be selected from various existing commercially available bolts.

[0019] The second nut is closer to the cap head than the first nut. Therefore, a gap can be formed between the second nut and the cap head, and the flange of the fixing member can protrude into the gap to prevent the fixing member from falling out.

[0020] The internal thread diameter of the second nut is larger than the outer diameter of the first threaded portion, one end of the small diameter portion forms an open first end, the other end of the small diameter portion is adjacent to one end of the large diameter portion, the other end of the large diameter portion forms the second end of the screw, and the second end has a cap head. Therefore, the second nut has the effect of being easily screwed into the large diameter portion.

[0021] The cross-sectional shape of the outer wall of the first nut and the second nut is the same polygon and size. Therefore, the inner wall of the fixing member only needs to form a matching single cross-sectional shape and size, which is easy to process and manufacture.

[0022] The fixing piece of the utility model is a hollow circular cylinder. The cylinder wall of the circular cylinder is provided with a plurality of opening grooves. The opening of each opening groove is formed at the bottom edge of the cylinder wall.

[0023] The fixing piece is a hollow circular cylinder, the cylinder wall of the circular cylinder has a number of opening slots, the opening of each opening slot is formed at the bottom of the cylinder wall, the number of the opening slots is a positive integer multiple of the number of the outer wall edges of the first nut and the second nut, and the polygonal corners of the first nut and the second nut are respectively stuck in the corresponding opening slots. Therefore, the fixing piece has the effect of being easy to process and manufacture.

[0024] The first end surface of the screw rod may also have a first engaging portion, the fixing member has a closed top, the inner surface of the top has a second engaging portion, and the second engaging portion engages with the first engaging portion. Therefore, the second engaging portion engages with the first engaging portion, which can further prevent the fixing member, the first nut and the second nut from rotating relative to the screw rod.

[0025] The fixing member is a shrink film made of PE, PVC, POF, OPS, or PET, and the shrink film is wrapped around the outer wall of the first nut and the second nut. Therefore, the fixing member is convenient to select and can be easily fixed on the outer wall of the first nut and the second nut, and can achieve the effect of reducing costs.

[0026] One end of the fixing piece has a flange protruding from the inner wall toward the center of the fixing piece, and a gap is provided between the second nut and the cap head, and the flange protrudes from the gap, thereby preventing the fixing piece from falling out.

[0027] The first end surface of the screw rod may also have a first engaging portion, the fixing member has a closed top, the inner surface of the top has a second engaging portion, and the second engaging portion engages with the first engaging portion. Therefore, the second engaging portion engages with the first engaging portion, thereby providing a second anti-loosening effect that prevents the first nut and the second nut from rotating synchronously relative to the screw rod.

[0028] One end of the fixing piece has a flange protruding from the inner wall toward the center of the fixing piece, so that the flange can protrude into the gap between the second nut and the cap head, thereby preventing the fixing piece from falling out.

[0029] The fixing member has a closed top, and the inner surface of the top has an engaging portion. Therefore, the closed top can form a second engaging portion and engage with the first engaging portion, which has a second anti-loosening effect of limiting the first nut and the second nut from rotating synchronously relative to the screw rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a front view of a combination of an existing fastening device with bidirectional threads.

[0031] Figure 2 It is a combined cross-sectional view of existing anti-loosening fasteners.

[0032] Figure 3 It is an exploded perspective view of the first embodiment of the utility model.

[0033] Figure 4 It is a cross-sectional view of the nut of the first embodiment of the utility model when it is not screwed together.

[0034] Figure 5 This is a cross-sectional view of the first embodiment of the utility model in use.

[0035] Figure 6 This is an exploded perspective view of the second embodiment of the utility model.

[0036] Figure 7 This is a cross-sectional view of the second embodiment of the utility model in use.

[0037] Figure 8 This is an exploded perspective view of the third embodiment of the utility model.

[0038] Fig. 9 This is a cross-sectional view of the third embodiment of the utility model in use.

[0039] Fig.10 It is a cross-sectional view along line AA in Figure 9.

[0040] [Description of Reference Numerals]

[0041] ﹝This utility model﹞

[0042] 1: Screw

[0043] 1a: First end

[0044] 1b: Second end

[0045] 1c: Small trail section

[0046] 1d: Large diameter part

[0047] 11: Threaded part

[0048] 11a: first threaded portion

[0049] 11b: Second threaded portion

[0050] 12: Hat head

[0051] 13: First fitting part 2: First nut

[0052] 21: Internal thread

[0053] 22:Outer wall

[0054] 3: Second nut

[0055] 31: Internal thread

[0056] 32:Outer wall

[0057] 4: Fixing parts

[0058] 41: Inner wall

[0059] 42: Flange

[0060] 43: Top

[0061] 44: Second fitting part 5: Fixing member

[0062] 51:Cylinder wall

[0063] 52: Opening slot

[0064] 53: Top

[0065] 54: Second fitting portion 55: Flange

[0066] F: Fixtures

[0067] G: Gap

[0068] ﹝Common Use﹞

[0069] 8: Bolts

[0070] 8a: right-hand threaded rod 8b: left-hand threaded rod 81: first nut

[0071] 82: Second nut

[0072] 83: Docking card slot

[0073] 84: Raised block

[0074] 9: Screw

[0075] 9a: Clockwise thread segment

[0076] 9b: Counterclockwise thread segment

[0077] 93: Groove

[0078] 94: Bump. DETAILED DESCRIPTION

[0079] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the preferred embodiments of the present invention are given below and described in detail with reference to the accompanying drawings.

[0080] The directions or their approximate terms described in the present invention, such as front, back, left, right, top, bottom, inside, outside, side, etc., mainly refer to the directions of the drawings, and each direction or its approximate terms are only used to assist in the description and understanding of the various embodiments of the present invention, and are not used to limit the present invention.

[0081] Please refer to Figure 1 , 2As shown, it is the first embodiment of the nut anti-loosening structure of the utility model, which can include a screw rod 1, a first nut 2, a second nut 3 and a fixing member 4. The first nut 2 and the second nut 3 can be screwed into the screw rod 1, and the fixing member 4 can be used to limit the first nut 2 and the second nut 3 to rotate only in the same direction but not in opposite directions.

[0082] The screw rod 1 can be an existing rod or bolt with a thread, and the utility model is not limited thereto. The screw rod 1 has a first end 1a and a second end 1b. At least one end of the screw rod 1 forms an open end. The screw rod 1 has a threaded portion 11, and the threaded portion 11 is connected to the at least one open end. In this embodiment, the screw rod 1 is described as a bolt. The first end 1a of the screw rod 1 forms an open end, the threaded portion 11 is connected to the first end 1a, and the second end 1b of the screw rod 1 can be a non-open end with a cap head 12, or the second end 1b of the screw rod 1 is fixed to a predetermined position. The threaded portion 11 has a first thread that is screwed in a first direction and a second thread that is screwed in a second direction. The directions of the screwing in the first direction and the screwing in the second direction are opposite, that is, the first thread and the second thread can be a thread that is screwed in a clockwise direction and a thread that is screwed in a counterclockwise direction.

[0083] The first nut 2 has an internal thread 21 and an outer wall 22. The first nut 2 can be screwed into the threaded portion 11 of the screw rod 1 by the internal thread 21. The screwing direction can be screwed in the first direction or in the second direction, which is not limited by the present invention. The outer wall 22 is located on the outer surface of the first nut 2. The cross-sectional shape of the outer wall 22 can be a polygonal shape such as a quadrilateral or hexagon, so that the first nut 2 can be driven and rotated by a tool.

[0084] The second nut 3 also has an internal thread 31 and an outer wall 32. The second nut 3 can be screwed into the threaded portion 11 of the screw rod 1 by the internal thread 31. The screwing direction of the second nut 3 is opposite to that of the first nut 2. The outer wall 32 is located on the outer surface of the second nut 3. The cross-sectional shape of the outer wall 32 can be an existing polygonal shape such as a quadrilateral or hexagon, so that the second nut 3 can be driven and rotated by a tool. The cross-sectional shape and size of the outer wall 32 of the second nut 3 can be the same as or different from the cross-sectional shape and size of the outer wall 22 of the first nut 2. Preferably, the second nut 3 is adjacent to the cap head 12, and the cross-sectional shape and size of the outer wall 32 of the second nut 3 are the same as the cross-sectional shape and size of the outer wall 22 of the first nut 2.

[0085] The fixing member 4 has a cylindrical body with an inner wall 41, and the cross-sectional shape and size of the inner wall 41 match the cross-sectional shape and size of the outer walls 22 and 32 of the first nut 2 and the second nut 3, that is, the fixing member 4 can be sleeved on the outer walls 22 and 32 of the first nut 2 and the second nut 3 by the inner wall 41, so that the first nut 2 and the second nut 3 can form a whole, so that the first nut 2 and the second nut 3 cannot rotate independently relative to the fixing member 4. The fixing member 4 can be made of a hard material such as plastic and metal, or can be a shrink film of PE, PVC, POF, OPS, PET and the like, so that the shrink film can be coated on the outer walls 22 and 32 of the first nut 2 and the second nut 3, so that the shrink film can form the fixing member 4.

[0086] Preferably, one end of the fixing member 4 has a flange 42 protruding from the inner wall 41 toward the center direction of the fixing member 4. When the first nut 2 and the second nut 3 are tightly screwed into the threaded portion 11 of the screw rod 1, a gap portion G is provided between the second nut 3 and the cap head 12 (as shown in FIG. 5 ). The gap portion G can be formed by the chamfer of the second nut 3. The fixing member 4 can be matchedly sleeved on the outer walls 22, 32 of the first nut 2 and the second nut 3 from the first end 1a of the screw rod 1 toward the second end 1b, and the flange 42 protrudes from the gap portion G. Therefore, the fixing member 4 can be prevented from escaping from the outer walls 22, 32 of the first nut 2 and the second nut 3.

[0087] Please refer to Figure 4 , 5 As shown, it is the use situation of the first embodiment of the nut anti-loosening structure of the utility model. The second end 1b of the screw rod 1 can be positioned on a fixing object F, the first end 1a of the screw rod 1 can protrude from a surface of the fixing object F, the first nut 2 and the second nut 3 can be screwed into the threaded portion 11 of the screw rod 1, and the fixing member 4 can be matchedly sleeved on the outer walls 22, 32, and the flange 42 of the fixing member 4 protrudes from the gap portion G. Therefore, the fixing member 4 can reliably position the first nut 2 and the second nut 3 on the threaded portion 11 of the screw rod 1. Therefore, when the fixing object F vibrates and causes the first nut 2 and the second nut 3 to loosen, the first nut 2 and the second nut 3 are matched with each other on the outer walls 22 and 32 by the fixing member 4. Not only can the first nut 2 and the second nut 3 not rotate independently relative to the screw rod 1, but also because the first nut 2 and the second nut 3 are screwed in opposite directions, a restraining effect is formed, so that the first nut 2 and the second nut 3 and the fixing member 4 cannot rotate synchronously in a single direction relative to the screw rod 1, thereby achieving the effect of preventing the first nut 2 and the second nut 3 from loosening.

[0088] Please refer to Figure 6 , 7 As shown, it is a second embodiment of the nut anti-loosening structure of the utility model. In this embodiment, the screw rod 1 has a small diameter portion 1c and a large diameter portion 1d with two different outer diameters. One end of the small diameter portion 1c forms the open first end 1a, and the other end of the small diameter portion 1c is adjacent to one end of the large diameter portion 1d. The other end of the large diameter portion 1d forms the second end 1b of the screw rod 1; the small diameter portion 1c has a first threaded portion 11a, and the large diameter portion 1d has a second threaded portion 11b. The first threaded portion 11a and the second threaded portion 11b have opposite screwing directions. The first threaded portion 11a can be screwed with the first nut 2, and the second threaded portion 11b can be screwed with the second nut 3. The aperture size of the internal thread 21 of the second threaded portion 11b is preferably larger than the outer diameter size of the first threaded portion 11a, so that the internal thread 31 of the second nut 3 can be screwed into the second threaded portion 11b from the first end 1a of the screw 1 through the first threaded portion 11a. Therefore, the second end 1b of the screw 1 can also form a non-open end with a cap head 12, or the second end 1b of the screw 1 can be fixed to a predetermined position.

[0089] The first nut 2 and the second nut 3 each have an internal thread 21, 31 and an outer wall 22, 32. The internal threads 21, 31 of the first nut 2 and the second nut 3 have different screwing directions. The internal thread 21 of the first nut 2 can be screwed with the first threaded portion 11a of the screw rod 1, and the internal thread 31 of the second nut 3 can be screwed with the second threaded portion 11b of the screw rod 1. The cross-sectional shape of the outer walls 22, 32 of the first nut 2 and the second nut 3 can be an existing polygonal shape such as a quadrilateral or hexagon, so that the first nut 2 and the second nut 3 can be driven and rotated by a tool.

[0090] The cross-sectional shape and size of the outer walls 22, 32 of the first nut 2 and the second nut 3 may be the same or different. Preferably, the cross-sectional shape and size of the outer walls 22, 32 of the first nut 2 and the second nut 3 are the same. Therefore, the inner wall 41 of the fixing member 4 only needs to form a matching single cross-sectional shape and size, and the fixing member 4 can be sleeved on the outer walls 22, 32 of the first nut 2 and the second nut 3 by the inner wall 41. Therefore, the first nut 2 and the second nut 3 are not only unable to rotate independently relative to the screw rod 1, but also because the first nut 2 and the second nut 3 are screwed in opposite directions, a restraining effect is formed, so that the first nut 2, the second nut 3 and the fixing member 4 cannot rotate synchronously relative to the screw rod 1.

[0091] In addition, when the cross-sectional shapes and sizes of the outer walls 22, 32 of the first nut 2 and the second nut 3 are different, it is only necessary to change the cross-sectional shape and size of the inner wall 41 of the fixing member 4 to the corresponding cross-sectional shape and size when the first nut 2 and the second nut 3 are tightened, so that the inner wall 41 of the fixing member 4 can be matched and sleeved on the outer walls 22, 32, so that the fixing member 4 can limit the first nut 2 and the second nut 3 from rotating independently relative to the screw rod 1. This is understandable to those with ordinary knowledge in the technical field to which the utility model belongs, and will not be elaborated here.

[0092] Please continue to refer to Figure 6 , 7 As shown, the screw rod 1 described in the above embodiments may also have a first engaging portion 13 on the end surface of the first end 1a of the screw rod 1, and the fixing member 4 may have a closed top 43, and the inner surface of the top 43 may have a second engaging portion 44, and the second engaging portion 44 may engage with the first engaging portion 13, so that the fixing member 4 cannot rotate relative to the screw rod 1. Therefore, when the fixing member 4 is sleeved on the outer walls 22 and 32 of the first nut 2 and the second nut 3, the fixing member 4 may not only restrict the first nut 2 and the second nut 3 from rotating independently relative to the screw rod 1, but also further prevent the fixing member 4, the first nut 2 and the second nut 3 from rotating relative to the screw rod 1 by engaging the second engaging portion 44 with the first engaging portion 13. The first engaging portion 13 and the second engaging portion 44 may be matched with each other in the form of a straight groove, a cross groove, a groove, a tooth, a convex block, a convex strip, etc., and the present invention is not limited thereto.

[0093] Please refer to Figure 8 , 9As shown in Figure 10, it is another embodiment of the nut anti-loosening structure of the utility model. The screw rod 1 can be constructed as described in the above embodiments. In this embodiment, the internal threads 21 and 31 of the first nut 2 and the second nut 3 have different screwing directions, and the outer walls 22 and 32 of the first nut 2 and the second nut 3 are in the same polygonal shape and size. The fixing member 5 is a hollow circular cylinder, and the cylinder wall 51 of the circular cylinder has a number of open grooves 52. The opening of each of the open grooves 52 is formed at the bottom edge of the cylinder wall 51, and the number of the open grooves 52 is a positive integer multiple of the number of sides of the outer walls 22 and 32 of the first nut 2 and the second nut 3. Thus, when the first nut 2 and the second nut 3 are tightly screwed on the threaded portion 11 of the screw rod 1, and the polygonal shapes of the outer walls 22 and 32 of the first nut 2 and the second nut 3 are aligned, the fixing member 5 can be sleeved on the circumference of the first nut 2 and the second nut 3. At this time, the polygonal corners of the first nut 2 and the second nut 3 can be respectively stuck in the corresponding opening grooves 52, and the fixing member 5 can limit the first nut 2 and the second nut 3 from rotating independently relative to the screw rod 1. In addition, the bottom end of the fixing member 5 can also have a flange 55 protruding from the barrel wall 51 toward the center of the fixing member 5, and the flange 55 can protrude from the gap G between the second nut 3 and the cap head 12.

[0094] Preferably, the fixing member 5 has a closed top 53, the first end 1a of the screw rod 1 has the first engaging portion 13, and the inner surface of the top 53 of the fixing member 5 has a second engaging portion 54, and the second engaging portion 54 can engage with the first engaging portion 13, so that the fixing member 5 cannot rotate relative to the screw rod 1. In this embodiment, the first engaging portion 13 is a polygonal column, and the second engaging portion 54 is a matching polygonal frame. Therefore, when the fixing member 5 is sleeved on the peripheral side of the first nut 2 and the second nut 3, the polygonal corners of the first nut 2 and the second nut 3 can be respectively stuck in the corresponding opening grooves 52 to form a restriction that the first nut 2 and the second nut 3 cannot rotate relative to the screw rod 1 alone. In addition, the second engaging portion 54 engages with the first engaging portion 13 to further form an effect of restricting the first nut 2 and the second nut 3 from rotating relative to the screw rod 1.

[0095] In summary, the nut anti-loosening structure of the utility model can achieve the first anti-loosening effect by sleeved the fixing piece on the circumference of the first nut and the second nut to limit the first nut and the second nut from rotating independently relative to the screw rod. Furthermore, the first end face of the screw rod has a first engaging portion, and the top inner surface of the fixing piece has a second engaging portion, and the second engaging portion can be engaged with the first engaging portion to form the second anti-loosening effect of limiting the first nut and the second nut from rotating synchronously relative to the screw rod.

[0096] Although the present invention has been disclosed using the above preferred embodiments, they are not intended to limit the present invention. Any person skilled in the art may make various changes and modifications to the above embodiments without departing from the spirit and scope of the present invention, and the technical scope protected by the present invention is still within the scope of the present invention. Therefore, the protection scope of the present invention shall include all changes within the meaning and equivalent scope of the attached patent application.

Claims

1. A nut anti-loosening structure, characterized in that: include: A screw having a first end and a second end, at least one end of the screw forming an open end, and a threaded portion on the screw, the threaded portion comprising a first thread screwed in a first direction and a second thread screwed in a second direction; a first nut having an internal thread and an outer wall, wherein the internal thread is screwed into the threaded portion of the screw in a first direction; a second nut having an internal thread and an outer wall, wherein the internal thread is screwed into the threaded portion of the screw in a second direction; and A fixing member is sleeved on the outer walls of the first nut and the second nut through an inner wall, so that the first nut and the second nut cannot rotate independently relative to the screw rod.

2. The nut anti-loosening structure according to claim 1, characterized in that: The first end of the screw rod forms an open end, the threaded portion is connected to the open end, and the second end of the screw rod has a cap head.

3. The nut anti-loosening structure according to claim 2, characterized in that: The second nut is closer to the cap head than the first nut.

4. A nut anti-loosening structure, characterized in that: include: A screw rod having a small diameter portion and a large diameter portion adjacent to each other, the small diameter portion having a first threaded portion, the large diameter portion having a second threaded portion, the first threaded portion and the second threaded portion having opposite screwing directions; a first nut having an internal thread and an outer wall, wherein the internal thread is screwed into the first threaded portion of the screw in a first direction; a second nut having an internal thread and an outer wall, wherein the internal thread is screwed into the second threaded portion of the screw in a second direction; and A fixing member is sleeved on the outer walls of the first nut and the second nut through an inner wall, so that the first nut and the second nut cannot rotate independently relative to the screw rod.

5. The nut anti-loosening structure according to claim 4, characterized in that: The internal thread hole diameter of the second nut is larger than the outer diameter of the first threaded portion, one end of the small diameter portion forms an open first end, the other end of the small diameter portion is adjacent to one end of the large diameter portion, the other end of the large diameter portion forms the second end of the screw, and the second end has a cap head.

6. The nut anti-loosening structure according to claim 1 or 4, characterized in that: The cross-sectional shapes of the outer walls of the first nut and the second nut are the same polygonal shape and size.

7. The nut anti-loosening structure according to claim 6, characterized in that: The fixing piece is a hollow circular cylinder, the cylinder wall of which has a number of open grooves, the openings of each of which are formed at the bottom edge of the cylinder wall, the number of which is a positive integer multiple of the number of edges of the outer walls of the first nut and the second nut, and the polygonal corners of the first nut and the second nut are respectively stuck in the corresponding open grooves.

8. The nut anti-loosening structure according to claim 7, characterized in that: The first end surface of the screw rod may also have a first engaging portion, the fixing member has a closed top, the inner surface of the top has a second engaging portion, and the second engaging portion is engaged with the first engaging portion.

9. The nut anti-loosening structure according to claim 1 or 4, characterized in that: The fixing piece is a shrink film made of PE, PVC, POF, OPS or PET, and the shrink film is coated on the outer wall of the first nut and the second nut.

10. The nut anti-loosening structure according to claim 3 or 5, characterized in that: One end of the fixing piece is provided with a flange protruding from the inner wall toward the center direction of the fixing piece, a gap portion is provided between the second nut and the cap head, and the flange protrudes from the gap portion.

11. The nut anti-loosening structure according to claim 10, characterized in that: The first end surface of the screw rod may also have a first engaging portion, the fixing member has a closed top, the inner surface of the top has a second engaging portion, and the second engaging portion is engaged with the first engaging portion.

12. A fixing member, characterized in that: The cylinder is made of plastic or metal and has an inner wall whose cross section is a regular polygon.

13. A fixing member, characterized in that: The utility model is a hollow circular cylinder, the cylinder wall of which is provided with a plurality of opening grooves, and the opening of each of the opening grooves is formed at the bottom edge of the cylinder wall.

14. The fixing member according to claim 12 or 13, characterized in that: One end of the fixing piece is provided with a flange protruding from the inner wall toward the center of the fixing piece.

15. The fixing member according to claim 12 or 13, characterized in that: The fixing piece has a closed top, and the inner surface of the top is provided with an engaging portion.

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