A self-locking screw

Abstract

The present invention discloses a self-locking screw, which relates to the technical field of screws, including a first nut, a second nut, a third nut, a fourth nut, a connecting rod, a first straight key, a second straight key, a connecting piece A and a connecting piece B, wherein three first keyways are arranged equidistantly above the connecting rod, a second keyway is arranged on one side below the connecting rod, a third keyway is arranged on one side inside the first nut, a threaded hole is arranged in the middle of the second straight key, the third keyway of the first nut is connected to the second keyway of the connecting rod through the first straight key; three wrapping grooves are arranged equidistantly inside the upper end of the fourth nut. The present invention has a novel structure, is quick and convenient to install and disassemble, and has a strong anti-loosening property. When in use, the vibration force can be converted into the locking force of the nut. The greater the vibration force, the stronger the clamping force, the better the stability, and is suitable for popularization and use.

Description

Technical Field

[0001] The invention relates to the technical field of screws, and in particular to a self-locking screw. Background Art

[0002] Screws are tools that use the physics and mathematical principles of the circular rotation of the inclined surface of an object and the friction force to gradually fasten objects and mechanical parts. Screws are a general term for fasteners. Screws are indispensable industrial necessities in daily life: such as very small screws used in cameras, glasses, clocks, electronics, etc.; general screws for televisions, electrical products, musical instruments, furniture, etc.; as for engineering, construction, and bridges, large screws and nuts are used; transportation equipment, airplanes, trams, cars, etc. use both large and small screws. Screws have important tasks in industry, and as long as there is industry on the earth, the function of screws will always be important.

[0003] The current common screws have the following main problems when locking and fixing the connecting parts:

[0004] 1. When ordinary threads are used for connection, the thread teeth in the thread pair composed of external threads and internal threads have a sudden change in cross-sectional position, resulting in stress concentration, which leads to poor root strength and easy damage to the thread teeth of ordinary threaded fasteners;

[0005] 2. When ordinary threads are used for connection, the screw connection is prone to loosening under external force vibration and has poor durability.

[0006] 3. Ordinary threads have problems such as uneven force distribution on each thread and stripping and biting;

[0007] As mentioned above, we have designed a self-locking screw to solve the above problems. Summary of the invention

[0008] The purpose of the present invention is to solve the shortcomings of the prior art and to provide a self-locking screw.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A self-locking screw comprises a first nut, a second nut, a third nut, a fourth nut, a connecting rod, a first straight key, a second straight key, a connecting piece A and a connecting piece B, wherein three first key slots are arranged equidistantly above the connecting rod, a second key slot is arranged on a lower side of the connecting rod, a third key slot is arranged on an inner side of the first nut, a threaded hole is arranged in the middle of the second straight key, the third key slot of the first nut is connected to the second key slot of the connecting rod through the first straight key; three wrapping grooves are arranged equidistantly inside the fourth nut, and the three wrapping grooves are connected to the three first key slots through the second straight key;

[0011] The first nut, the second nut, the third nut and the fourth nut are all provided with end face threads, and the end face threads are provided with thread lead angles. The end face thread of the first nut is located at the upper end face of the first nut, and the end face thread of the fourth nut is located at the lower end face of the fourth nut. The thread lead angles of the end face threads of the first nut and the fourth nut are both α. The end face threads of the second nut and the third nut are located at the upper and lower end faces of the second nut and the third nut. The thread lead angles of the lower end face of the second nut and the upper end face of the third nut are α, and the thread lead angles of the upper end face of the second nut and the lower end face of the third nut are β, and the end face thread lead angle β>α.

[0012] Preferably, the first nut, the second nut, the third nut and the fourth nut all have end face double-line single-thread threads, and the thread angle of the end face threads is 0 degrees.

[0013] Preferably, the first nut, the second nut, the third nut and the fourth nut are two groups of double-stacked end face threaded nuts, and the two groups of double-stacked end face threaded nuts constitute two groups of threaded connection pairs, the first nut and the second nut constitute one group of threaded connection pairs; the third nut and the fourth nut constitute another group of threaded connection pairs.

[0014] Preferably, when the two groups of double-stacked end face threaded nuts are against each other in the lowest position, there is a gap between the axial directions of the connecting rod. Preferably, when the double-stacked end face threaded nuts are not locked, a relative position angle of not less than 90° is reserved between the high and low positions of the β angle of the end face thread of the upper end of the second nut and the β angle of the end face thread of the lower end of the third nut.

[0015] Preferably, it also includes a gasket, and the gasket has different thicknesses according to the different heights of the connecting member A and the connecting member B.

[0016] Preferably, the three first keyways are trisection keyways adapted to be connected with the second straight key, the three wrapping grooves are trisection grooves, and trisection notches are provided at the connecting positions of the trisection grooves.

[0017] Preferably, the height of the first straight key is smaller than the thickness of the first nut.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: in the present invention, the first nut, the second nut, the third nut and the fourth nut are all provided with end face threads, and the end face threads are provided with thread lead angles. When connected and used, the first nut, the second nut, the third nut and the fourth nut are sequentially inserted into the connecting rod, and finally the three second straight keys are embedded in the first keyway divided into three equal parts above the connecting rod, and the middle threaded hole of the straight key is convenient for taking out from the waist groove of the connecting rod by a drawing die; the α angle of the end face thread of the upper end of the first nut and the α angle of the end face thread of the lower end of the second nut are abutted at the lowest position to form a set of end face thread connection pairs; the fourth nut is rotated right by an angle, so that the three identical straight keys embedded in the keyway divided into three equal parts above the connecting rod slide from the three-divided notch of the upper end of the fourth nut into the three-divided groove, and the position of the fourth nut is fixed when there is a pre-tightening force;

[0019] The following effects can be achieved:

[0020] 1. The nuts are connected by end threads (thread β and thread α), which will prevent the traditional thread pair consisting of external and internal threads from having poor root strength due to sudden changes in cross-sectional positions, stress concentration, and easy damage to the threads of ordinary threaded fasteners;

[0021] 2. Two nuts with different rotation directions can directly convert the loosening force of the left-handed nut into the tightening force of the right-handed nut, and similarly, the loosening force of the right-handed nut can be directly converted into the tightening force of the left-handed nut, converting the two opposing forces into mutual assistance and integration, ensuring that the clamping force of the connection is still maintained under strong vibration, which is better than fasteners that rely solely on friction to lock; it can solve the problem of loosening of equipment fasteners under strong vibration conditions;

[0022] 3. When in use, the left-handed nut is lifted to the left and the right-handed nut is moved to the right to make the β-angle thread surfaces of the left and right nuts counteract each other to obtain pre-tightening force. The fixing element can be locked with high or low pre-tightening force, which is not affected by the original tightening force and has durability. When locking, the mutual reaction force of the left-handed nut and the right-handed nut is used to achieve a structural anti-loosening effect. The special structure can convert the vibration force into the locking force of the nut. The greater the vibration force, the stronger the clamping force.

[0023] The invention has a novel structure, is quick and convenient to install and disassemble, and has strong anti-loosening properties. When in use, the vibration force can be converted into the locking force of the nut. The greater the vibration force, the stronger the clamping force and the better the stability, making it suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the structure of a self-locking screw proposed by the present invention;

[0025] Figure 2 This is a schematic structural diagram of a fourth nut of a self-locking screw proposed by the present invention;

[0026] Figure 3 This is a schematic structural diagram of a third nut of a self-locking screw proposed by the present invention;

[0027] Figure 4 This is a schematic structural diagram of a second nut of a self-locking screw proposed by the present invention;

[0028] Figure 5 A schematic structural diagram of a first nut of a self-locking screw proposed by the present invention;

[0029] Figure 6 A schematic structural diagram of a washer for a self-locking screw proposed by the present invention;

[0030] Figure 7 A schematic structural diagram of a second straight key of a self-locking screw provided by the present invention;

[0031] Figure 8 A top view of a second straight key of a self-locking screw provided by the present invention;

[0032] Fig. 9 A front view of a second straight key of a self-locking screw provided by the present invention;

[0033] Fig.10 for Fig. 9 AA section view;

[0034] Fig.11 A schematic structural diagram of a first straight key of a self-locking screw proposed by the present invention;

[0035] Fig.12 A schematic structural diagram of a connecting rod of a self-locking screw proposed by the present invention;

[0036] Fig.13 The present invention provides a cross-sectional view of a connecting rod of a self-locking screw.

[0037] In the figure: 1 first nut, 2 second nut, 3 third nut, 4 fourth nut, 5 connecting rod, 6 washer, 7 first straight key, 8 second straight key, 9 first keyway, 10 second keyway, 11 threaded hole, 12 third keyway, 13 wrapping groove. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0039] Reference Figure 1-13, a self-locking screw, comprising a first nut 1, a second nut 2, a third nut 3, a fourth nut 4, a connecting rod 5, a washer 6, a first straight key 7, a second straight key 8, a connecting piece A and a connecting piece B, three first key grooves 9 are equidistantly arranged above the connecting rod 5, a second key groove 10 is arranged on one side below the connecting rod 5, a third key groove 12 is arranged on one side inside the first nut 1, a threaded hole 11 is arranged in the middle of the second straight key 8, the third key groove 12 of the first nut 1 is connected to the second key groove 10 of the connecting rod 5 through the first straight key 7; the height of the first straight key 7 is less than the thickness of the first nut 1, three wrapping grooves 13 are equidistantly arranged inside the fourth nut 4, the three wrapping grooves 13 are connected to the three first key grooves 9 through the second straight key 8, the three first key grooves 9 are three-equally divided key grooves adapted to be connected with the second straight key 8, the three wrapping grooves 13 are three-equally divided grooves, and the connecting position of the three-equally divided grooves is provided with a three-equally divided notch;

[0040] The first nut 1, the second nut 2, the third nut 3, and the fourth nut 4 are all provided with end face threads, and the first nut 1, the second nut 2, the third nut 3, and the fourth nut 4 are all end face double-line single-tooth threads, and the tooth profile angle of the end face threads is 0 degrees. The end face threads are provided with thread lead angles, and the end face threads of the first nut 1 are located at the upper end face of the first nut 1, and the end face threads of the fourth nut 4 are located at the lower end face of the fourth nut 4. The thread lead angles of the end face threads of the first nut 1 and the fourth nut 4 are both α, and the end face threads of the second nut 2 and the third nut 3 are located at At the upper and lower end faces of the second nut 2 and the third nut 3, the thread lead angles of the lower end face of the second nut 2 and the upper end face of the third nut 3 are α, the thread lead angles of the upper end face of the second nut 2 and the lower end face of the third nut 3 are β, and the end face thread lead angle β>α; the first nut 1, the second nut 2, the third nut 3, and the fourth nut 4 are two groups of double-stacked end face threaded nuts, and the two groups of double-stacked end face threaded nuts constitute two groups of threaded connection pairs, the first nut 1 and the second nut 2 constitute one group of threaded connection pairs; the third nut 3 and the fourth nut 4 constitute another group of threaded connection pairs.

[0041] Embodiment: During installation, the connecting rod 5 passes through the connecting piece A and the connecting piece B, and the adjusting washer 6 and the first nut 1 are successively inserted into the connecting rod 5, sandwiching the two connecting pieces A and the connecting piece B therein, and the third keyway 12 of the first nut 1 is connected to the second keyway 10 of the connecting rod 5 through the straight key 7, and the first nut 1 can only move axially along the connecting rod 5; then the second nut 2, the third nut 3, and the fourth nut 4 are successively inserted into the connecting rod 5, and finally the three second straight keys 8 are inserted into the first keyway 9 divided into three equal parts above the connecting rod 5 through the notch divided into three equal parts above the fourth nut 4, and the straight key 8 is inserted into the first keyway 9 divided into three equal parts above the connecting rod 5. The threaded hole is convenient for taking out from the waist groove of the connecting rod 5 by a drawing die; the angle α of the end face thread of the upper end of the first nut 1 is abutted against the angle α of the end face thread of the lower end of the second nut 2 at the lowest position to form a set of end face thread connection pairs; the fourth nut 4 is rotated right by an angle, so that the three identical second straight keys 8 embedded in the three-divided keyway above the connecting rod 5 slide from the three-divided notch at the upper end of the fourth nut 4 into the three-divided groove, and the fourth nut 4 is fixed in position when there is a pre-tightening force; wherein, the outer side of the three identical second straight keys 8 is an arc-shaped structure, which is adapted to the circular arc surface of the three-divided groove of the fourth nut 4;

[0042] The α angle of the thread on the upper end of the third nut 3 and the α angle of the thread on the lower end of the fourth nut 4 are against each other at the lowest position, forming another set of end thread connection pairs; according to the different heights of the connecting parts, the adjusting washer 6 can be selected with different thicknesses, but it is necessary to ensure that there is a gap between the two sets of nuts in the axial direction of the connecting rod when they are against each other at the lowest position; when the double-stacked nut is not locked, the β angle of the thread on the upper end of the second nut 2 and the β angle of the thread on the lower end of the third nut 3 (between the high and low positions) should reserve a relative position angle of not less than 90°. When the nuts are locked, the second nut 2 and the third nut 3 are simultaneously rotated left and right. Since the α angle of the thread on the lower end of the second nut 2 and the α angle of the thread on the upper end of the first nut 1 are against each other at the lowest position, as the second nut 2 is rotated left, the second nut 2 is lifted upward along the connecting rod.

[0043] Similarly, the α angle of the upper end face thread of the second nut 3 and the α angle of the lower end face thread of the fourth nut 4 are counteracted at the lowest position. As the third nut 3 rotates right, the third nut 3 slides downward along the connecting rod until the β angle of the lower end face thread of the third nut 3 and the β angle of the upper end face thread of the second nut 2 are counteracted. The greater the nut preload force, the stronger the locking force.

[0044] It should be noted that in this plan:

[0045] 1. During the installation process, the first nut 1, the second nut 2, the third nut 3, the fourth nut 4 and the connecting rod 5 can be repeatedly assembled and disassembled and reused.

[0046] 2. During use, the second nut 2 and the third nut 3 are rotated left and right at the same time, and locking can be achieved by rotating a small angle; on the contrary, loosening can be achieved, which is convenient for quick installation and disassembly.

[0047] 3. During use, choose a smaller helix angle to achieve both friction self-locking and structural self-locking.

[0048] 4. Because the thread pair is between the end faces of the double-stacked nut, the thread teeth are located on the entire end face of the nut, and the thread width is not restricted. There is no problem of sudden change in the cross-sectional position of the thread teeth in the thread pair composed of the external thread and the internal thread, resulting in poor root strength and easy damage to the thread teeth of ordinary threaded fasteners due to stress concentration. There are also no problems such as uneven force distribution on the threads of ordinary threads, stripping and biting. The three-part keyway on the upper part of the connecting rod does not change the cross-sectional diameter of the connecting rod. The connecting rod body has high strength and can bear a higher load-bearing capacity. There is no problem of small root diameter and low tensile strength of ordinary bolts in the past. The nut and the connecting rod can achieve higher strength and hardness after heat treatment.

[0049] 5. The special groove structure on the upper end surface of the fourth nut 4 wraps the groove 13 that wraps the three equally distributed second straight keys 8, which has good stability when subjected to force and high structural strength.

[0050] 6. The thread on the end face of the nut can be designed as left-hand or right-hand. Regardless of whether the thread is left-hand or right-hand, the thread direction of the two sets of double-stack nuts is the same. The thread on the end face of the nut can be single-thread or multi-thread. Since the thread is only on the end face of the nut, there is no problem of multi-thread thread giving way.

[0051] 7. The left-handed nut is lifted to the left and the right-handed nut is moved to the right to make the β-angle thread surfaces of the left and right nuts counteract each other to obtain pre-tightening force. The fixed components can be locked with high or low pre-tightening force, which is not affected by the original tightening force and has durability.

[0052] 8. The left-handed nut and the right-handed nut must be rotated in opposite directions at the same time to achieve the purpose of loosening. Any single nut cannot be loosened by rotating in the opposite direction. This result is achieved by utilizing the mutual reaction force when the left-handed nut and the right-handed nut cooperate to achieve a structural anti-loosening effect. The special structure can convert the vibration force into the locking force of the nut. The greater the vibration force, the stronger the clamping force;

[0053] 9. The thread lead angle β between the upper end face of the second nut 2 and the lower end face of the third nut 3 is greater than the thread lead angle α of the two sets of end face thread connection pairs, so the structure has better anti-loosening performance.

[0054] More specifically, under the conditions of working vibration and impact load, the left-handed second nut 2 and the right-handed third nut 3 may both have a tendency to loosen. When the left-handed second nut 2 has a tendency to loosen, the reaction force in the normal direction of the β angle of the lower thread end face of the third nut 3 that abuts against the β angle of the upper thread end face of the second nut 2 causes the third nut 3 to move rightward and downward, thereby preventing the left-handed second nut 2 from loosening; when the right-handed third nut 3 has a tendency to loosen, the β angle of the upper thread end face of the second nut 2 that abuts against the β angle of the lower thread end face of the third nut 3 causes the third nut 3 to move rightward and downward, thereby preventing the left-handed second nut 2 from loosening; The reaction force in the angular normal direction causes the second nut 2 to move leftward and upward, thereby preventing the right-handed third nut 3 from loosening; the two nuts with different rotation directions can directly convert the loosening force of the left-handed nut into the tightening force of the right-handed nut, and similarly, can directly convert the loosening force of the right-handed nut into the tightening force of the left-handed nut, converting the two relative forces into mutual assistance and fusion, ensuring that the clamping force of the connection is still maintained under strong vibration, which is better than fasteners that simply rely on friction to lock; it can solve the problem of loosening of equipment fasteners under strong vibration conditions.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0057] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A self-locking screw, characterized in that: The invention comprises a first nut (1), a second nut (2), a third nut (3), a fourth nut (4), a connecting rod (5), a first straight key (7), a second straight key (8), a connecting piece A and a connecting piece B, wherein three first key grooves (9) are equidistantly arranged above the connecting rod (5), a second key groove (10) is arranged on one side below the connecting rod (5), a third key groove (12) is arranged on one side inside the first nut (1), a threaded hole (11) is arranged in the middle of the second straight key (8), and the third key groove (12) of the first nut (1) is connected to the second key groove (10) of the connecting rod (5) via the first straight key (7); three wrapping grooves (13) are equidistantly arranged inside the upper end of the fourth nut (4), and the three wrapping grooves (13) are connected to the three first key grooves (9) via the second straight key (8); The first nut (1), the second nut (2), the third nut (3) and the fourth nut (4) are all provided with end face threads, and the end face threads are provided with thread lead angles. The end face thread of the first nut (1) is located at the upper end face of the first nut (1), and the end face thread of the fourth nut (4) is located at the lower end face of the fourth nut (4). The thread lead angles of the end face threads of the first nut (1) and the fourth nut (4) are both α. The end face threads of the second nut (2) and the third nut (3) are located at the upper and lower end faces of the second nut (2) and the third nut (3). The thread lead angles of the lower end face of the second nut (2) and the upper end face of the third nut (3) are α, and the thread lead angles of the upper end face of the second nut (2) and the lower end face of the third nut (3) are β, and the end face thread lead angle β>α. The first nut (1), the second nut (2), the third nut (3), and the fourth nut (4) all have end face double-line single-thread threads, and the thread angle of the end face threads is 0 degrees; The first nut (1), the second nut (2), the third nut (3) and the fourth nut (4) are two groups of double-stacked end-face threaded nuts, which form two groups of threaded connection pairs. The first nut (1) and the second nut (2) form one group of threaded connection pairs; the third nut (3) and the fourth nut (4) form another group of threaded connection pairs. It also includes a gasket (6), wherein the gasket (6) has different thicknesses according to the different heights of the connecting member A and the connecting member B.

2. A self-locking screw according to claim 1, characterized in that: When the two sets of double-stacked end face threaded nuts abut against each other at the lowest position, there is a gap between the connecting rods (5) in the axial direction. When the double-stacked end face threaded nuts are not locked, a relative position angle of not less than 90° is reserved between the β angle of the upper end face thread of the second nut (2) and the β angle of the lower end face thread of the third nut (3).

3. A self-locking screw according to claim 1, characterized in that: The three first keyways (9) are trisection keyways adapted to be connected with the second straight key (8), the three wrapping grooves (13) are trisection grooves, and trisection notches are provided at the connecting positions of the trisection grooves.

4. A self-locking screw according to claim 1, characterized in that: The height of the first straight key (7) is less than the thickness of the first nut (1).

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