Automatic locking bolt external sleeve and construction method thereof

Abstract

The present invention relates to an automatic interlocking bolt external sleeve and a construction method thereof, comprising an outer sleeve, an inner spacer and a fork rod; the outer sleeve has a top plate and a bottom plate, a measuring element is fixed on the top of the top plate, and a bolt hole is opened in the center of the bottom plate for inserting an existing bolt; the inner spacer is located inside the outer sleeve and is coaxially arranged with the outer sleeve, the diameter of the inner spacer is larger than the aperture of the bolt hole, the top of the inner spacer is fixed to the bottom of the top plate of the outer sleeve, and the bottom of the inner spacer is fixed to the top of the bottom plate of the outer sleeve; the fork rod obliquely passes through the inner spacer and the outer sleeve, the bottom of the fork rod has a fork rod circular axis and is located outside the outer sleeve, and the top of the fork rod obliquely clamps the thread of the existing bolt. The present invention can be based on the bolts left after the installation of various existing equipment, and can realize the convenient installation of various measuring elements through the bolt external sleeve, and can be directly disassembled and reused without the help of any tools, thereby reducing the difficulty of underground engineering monitoring, reducing operation and maintenance costs, and improving maintenance efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of underground engineering construction, and in particular to an automatic interlocking bolt external sleeve and a construction method thereof. Background Art

[0002] Various underground projects in long-term service require daily monitoring to ensure operational safety and timely disease prevention and treatment. A large number of measuring components are installed in corresponding locations of underground projects, especially in the tunnel vaults and waist areas that are prone to cracks and water leakage, to collect relevant monitoring data and understand the operational status parameters of underground projects.

[0003] However, the installation of measuring elements in underground projects requires fixed installation. Due to the operational characteristics of underground projects, the adverse effects of train vibration, surface road traffic, and other incidental loads must be considered. Furthermore, current conventional installation methods for measuring elements, often based on post-installed anchor bolts, can increase damage to underground structures, increase structural safety risks, and impact the durability of underground projects.

[0004] Therefore, it is necessary to propose new measures to overcome the above-mentioned defects. Summary of the Invention

[0005] The purpose of the present invention is to provide an automatic locking bolt external sleeve and a construction method thereof, so as to solve the problems existing in the existing installation and fixation that the adverse effects in underground engineering are not considered and the potential safety hazards of the structure are increased.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] An automatic locking bolt external sleeve, the bolt external sleeve comprising an outer sleeve, an inner spacer and a fork rod;

[0008] The outer sleeve has a top plate and a bottom plate, a measuring element is fixed on the top of the top plate, and a bolt hole is opened in the center of the bottom plate for inserting an existing bolt;

[0009] The inner spacer is located inside the outer sleeve and is coaxially arranged with the outer sleeve. The diameter of the inner spacer is larger than the diameter of the bolt hole. The top of the inner spacer is fixed to the bottom of the top plate of the outer sleeve, and the bottom of the inner spacer is fixed to the top of the bottom plate of the outer sleeve.

[0010] The fork rod obliquely passes through the inner spacer and the outer sleeve, a fork rod circular axis is provided at the bottom of the fork rod and is located outside the outer sleeve, and the top of the fork rod obliquely clamps the thread of the existing bolt.

[0011] Furthermore, an unlocking slide is provided outside the outer sleeve and is coaxial with the outer sleeve, and the circular axis of the fork rod is located in a rotation groove provided on the inner wall of the unlocking slide;

[0012] The circular shaft of the fork rod is spherical and can rotate in the rotation groove of the unlocking slide cylinder.

[0013] Furthermore, an oblique spring device is provided between the fork rod and the outer sleeve.

[0014] Furthermore, the oblique spring device includes an oblique spring, an oblique rod, an L-shaped steel plate and an oblique spring compartment;

[0015] The oblique spring magazine is fixed to the side of the fork rod, the L-shaped steel plate is fixed to the inner wall of the outer sleeve, and one end of the oblique rod is fixed to the L-shaped steel plate;

[0016] The oblique spring is sheathed outside the oblique rod and is located in the oblique spring compartment, with two ends respectively contacting the L-shaped steel plate and the fork rod.

[0017] Furthermore, a vertical spring device is provided between the bottom of the unlocking slide cylinder and the outer wall of the outer sleeve.

[0018] Furthermore, the vertical spring device includes a vertical spring, a vertical rod, a vertical spring compartment, a vertical spring base, a spring vertical cylinder and a steel cover plate;

[0019] The vertical spring base is fixed to the outer wall of the outer sleeve, the vertical spring cylinder is located outside the vertical spring base and on the top of the vertical spring base, and a vertical spring compartment is provided on the top surface of the vertical spring base;

[0020] A steel cover plate is provided in the spring vertical cylinder, the outer periphery of the steel cover plate is in sliding contact with the inner wall of the spring vertical cylinder, and a vertical rod is provided on the bottom surface of the steel cover plate;

[0021] The vertical spring is located in the spring vertical tube and in the vertical spring compartment. The vertical spring is sheathed outside the vertical rod, and the top and bottom are in contact with the steel cover plate and the vertical spring base respectively.

[0022] Furthermore, the outer wall of the unlocking slide is provided with a lug.

[0023] Furthermore, a support hole is provided on the inner spacer, and the fork rod obliquely passes through the support hole, and the hole diameter of the support hole is larger than the outer diameter of the fork rod.

[0024] Furthermore, the outer sleeve is provided with an insertion hole, the fork rod obliquely passes through the insertion hole, and the hole diameter of the insertion hole is larger than the outer diameter of the fork rod.

[0025] On the other hand, a method for constructing the automatic locking bolt external sleeve is provided, the method comprising:

[0026] During installation, insert the existing bolt into the bolt hole at the bottom of the outer sleeve, and the top of the fork rod will contact the thread of the existing bolt at an angle, so the retreat of the existing bolt is restricted;

[0027] When disassembling, press the lug and move the unlock slide downward. The fork rod axis moves downward, the vertical spring and the oblique spring are compressed at the same time, the fork rod rotates outward around the fork rod axis, the top of the fork rod disengages from the thread of the existing bolt, and the retraction of the existing bolt is released.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention provides an automatic interlocking bolt external sleeve and a construction method thereof, which can be used based on the bolts left over from the installation of various existing equipment, such as bolts at the hand hole position of shield pipe segments, exposed bolts from the installation of contact lines or fire water pipes, etc. Through the bolt external sleeve, various measuring components can be conveniently installed and can be directly disassembled without the aid of any tools, thereby reducing the monitoring and operation and maintenance costs of underground projects, and improving the monitoring efficiency and long-term stable operation of underground projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, they can also obtain drawings of other embodiments based on these drawings.

[0031] Figure 1 This is a schematic diagram of the installation of the present invention (bolts inserted and locked).

[0032] Figure 2 This is a vertical view of the present invention (the bolts can be removed).

[0033] Figure 3 It is a cross-sectional view of the present invention.

[0034] Figure 4 This is the layout diagram of the oblique spring device.

[0035] Figure 5 This is the layout diagram of the vertical spring device.

[0036] The symbols in the figure are:

[0037] 1-outer sleeve, 2-inner spacer, 3-unlocking slide, 4-measuring element, 5-vertical spring device, 6-fork rod, 7-oblique spring device, 8-existing bolt;

[0038] 21-support hole;

[0039] 31-lug;

[0040] 51-vertical spring, 52-vertical rod, 53-vertical spring chamber, 54-vertical spring base, 55-spring vertical cylinder, 56-steel cover;

[0041] 61-fork rod circular shaft;

[0042] 71- oblique spring, 72- oblique rod, 73- L-shaped steel plate, 74- oblique spring magazine. DETAILED DESCRIPTION

[0043] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0044] In the description of the present invention, it should be understood that the terms "oblique", "horizontal", "vertical", "lateral", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are 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, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0045] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "disposed" should be understood in a broad sense. For example, they may refer to fixed connection or disposition, detachable connection or disposition, or integral connection or disposition. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0046] It should also be noted that although the steps are described in order, in some cases they may be performed in an order different from that shown, and this should not be construed as limiting the order of the steps.

[0047] In a specific embodiment, Figure 1 The direction from bottom to top is defined as the vertical direction, and the direction perpendicular to it is defined as the horizontal direction.

[0048] Underground projects may contain numerous bolts or screws, such as in shield tunneling. Bolts located in handholes can provide conditions for the installation of measuring elements. Bolts used to install electromechanical equipment in underground projects also provide conditions for the installation of measuring elements. Conventional bolt and nut fastening methods, however, inevitably loosen due to the long-term vibrations they endure, such as those caused by train operation in urban traffic and vehicle vibration on highways.

[0049] In order to effectively utilize existing underground engineering components, realize the fast and convenient installation of measuring elements, avoid the damage of conventional post-anchor bolt drilling operations to underground structures, and avoid the loosening phenomenon of mechanical bite between conventional bolts and nuts, the present invention provides an automatic locking bolt external sleeve. According to the characteristics of underground engineering, without increasing the structural burden and safety hazards, based on the bolts left by the installation of various existing equipment, such as the bolts at the hand hole position of the shield pipe segment, the exposed bolts of the contact network or fire water pipe installation, etc., the bolt external sleeve can be used to realize the convenient installation of various measuring elements, and can be directly disassembled without the aid of any tools, thereby reducing the cost of underground engineering monitoring and operation and maintenance and improving the efficiency of underground engineering monitoring.

[0050] Specifically, such as Figure 1 The bolt external sleeve includes an outer sleeve 1, an inner spacer 2, an unlocking slide 3 and a fork rod 6.

[0051] The outer sleeve 1 has a top plate and a bottom plate. A measuring element 4 is fixed to the top of the top plate, and a bolt hole is provided in the center of the bottom plate for inserting an existing bolt 8. The bolt hole has an L-shaped structure, and the hole size matches the diameter of the existing bolt 8. The outer sleeve 1 is also provided with a socket.

[0052] The inner spacer 2 is located inside the outer sleeve 1 and is coaxially arranged with the outer sleeve 1. The diameter of the inner spacer 2 is larger than the diameter of the bolt hole. The top of the inner spacer 2 is fixed to the bottom of the top plate of the outer sleeve 1, and the bottom of the inner spacer 2 is fixed to the top of the bottom plate of the outer sleeve 1. A support hole 21 is provided on the inner spacer 2.

[0053] The fork rod 6 obliquely passes through the support hole 21 of the inner spacer 2 and the insertion hole of the outer sleeve 1. The aperture of the support hole 21 is larger than the outer diameter of the fork rod 6, and the aperture of the insertion hole is larger than the outer diameter of the fork rod 6. Therefore, the fork rod 6 can move and rotate limitedly in the support hole 21 and the insertion hole. The top of the fork rod 6 has at least two forks, which fork after passing through the support hole 21. The top has a conical structure, which is conducive to its mechanical engagement with the existing bolt 8 thread. The bottom of the fork rod 6 has a fork rod circular axis 61 and is located outside the outer sleeve 1. A plurality of fork rods 6 are circumferentially arranged in the outer sleeve 1 and are evenly arranged. They can be distributed at intervals of about 30°, such as Figure 3After the existing bolt 8 is inserted into the bottom of the outer sleeve 1, the diameter of the circular outline formed by the top of the fork rod 6 should be slightly smaller than the diameter of the existing bolt 8, generally 2-3 times the thread height, to ensure the mechanical bite effect between the existing bolt 8 thread and the end of the fork rod 6.

[0054] The unlocking slide 3 is located outside the outer sleeve 1 and coaxial with it. The fork shaft 61 is positioned within a rotation groove on the inner wall of the unlocking slide 3. The opening of the rotation groove should be approximately two-thirds of the groove's diameter to ensure that the fork shaft 61 fits securely within the groove and can roll freely within it. The outer wall of the unlocking slide 3 is provided with a lug 31, larger at the top and smaller at the bottom. This lug 31 secures the unlocking slide 3, allowing it to move up and down outside the outer sleeve 1.

[0055] An oblique spring device 7 is also provided between the fork rod 6 and the outer sleeve 1. Figure 4 The oblique spring device 7 has a circular cross-section and includes an oblique spring 71, an oblique rod 72, an L-shaped steel plate 73, and an oblique spring compartment 74. The oblique spring compartment 74 is fixed to the side of the fork rod 6, the L-shaped steel plate 73 is fixed to the inner wall of the outer sleeve 1, and one end of the oblique rod 72 is fixed to the L-shaped steel plate 73. The oblique spring 71 is sheathed around the oblique rod 72 and located within the oblique spring compartment 74, with its ends contacting the surface of the L-shaped steel plate 73 and the side of the fork rod 6, respectively. Each fork rod 6 is equipped with an oblique spring device 7. When the fork rod 6 rotates outward, the oblique spring 71 is compressed within the oblique spring compartment 74. In other embodiments, an additional oblique spring compartment 74 may be provided and fixed to the L-shaped steel plate 73. The two oblique spring compartments 74 can be inserted into each other, and the oblique spring 71 is located within the two oblique spring compartments 74. The oblique spring compartment 74 has a circular cross-section, and its internal clearance is about 2-3 cm larger than that of the oblique spring 71 , thus reserving necessary space for the movement of the oblique spring 71 during the movement of the fork rod 6 .

[0056] A vertical spring device 5 is also provided between the bottom of the unlocking slide 3 and the outer wall of the outer sleeve 1. Figure 5The cross section of the vertical spring device 5 is circular and includes a vertical spring 51, a vertical rod 52, a vertical spring magazine 53, a vertical spring base 54, a spring vertical cylinder 55 and a steel cover plate 56; the vertical spring base 54 is fixed to the outer wall of the outer sleeve 1, the spring vertical cylinder 55 is located on the outside of the vertical spring base 54 and on the top of the vertical spring base 54, and the top surface of the vertical spring base 54 is provided with a vertical spring magazine 53, which can effectively prevent the vertical spring 51 from lateral displacement; a steel cover plate 56 is provided in the spring vertical cylinder 55, the outer periphery of the steel cover plate 56 is in sliding contact with the inner wall of the spring vertical cylinder 55, and the bottom surface of the steel cover plate 56 is provided with a vertical rod 52; the vertical spring 51 is located inside the spring vertical cylinder 55 and in the vertical spring magazine 53, the vertical spring 51 is sheathed outside the vertical rod 52, and the top and bottom respectively contact the steel cover plate 56 and the vertical spring base 54. The vertical rod 52 is at a certain distance from the vertical spring base 54, which matches the vertical sliding distance of the unlocking slide 3. The vertical spring device 5 is set in multiple pieces along the circumferential direction and is evenly arranged. It can be considered to be evenly distributed at intervals of about 30 degrees, and arranged in a cross-interval with the fork rod 6 along the circumferential direction. Figure 3 When the unlocking slide 3 moves downward, it presses down the steel cover plate 56 , and the vertical spring 51 is compressed downward in the vertical cylinder 55 and the vertical spring chamber 53 .

[0057] After the fork rod 6 and the existing bolt 8 are firmly engaged, the angle between the fork rod 6 and the horizontal direction is α It can be considered at about 45°, such as Figure 1 After the vertical rod 52 inside the vertical spring device 5 contacts the spring base 54, the angle between the fork rod 6 and the horizontal direction is α will increase by about 5°, increasing to Figure 2 in β The telescopic range of the vertical spring device 5 is mainly determined by the compression of the vertical spring 51 inside it and the distance between the vertical rod 52 and the spring base 54, which can generally be considered to be around 20 mm.

[0058] Among the components of the above-mentioned automatic locking bolt external sleeve, the outer sleeve 1, the inner spacer 2, the unlocking slide 3, the vertical spring device 5, the fork rod 6, the oblique spring device 7 and the existing bolt 8 can all be made of Q235 or Q345 steel. The measuring element 4 can be various displacement sensors or instruments. The springs involved in the vertical spring device 5 and the oblique spring device 7 must have good compression and elongation properties, and be in a zero compression state in the natural state (non-pressurized working condition) after installation.

[0059] The thickness of the outer ring steel plate of the outer sleeve 1 can generally be considered to be around 3-5 mm, and the thickness of the inner spacer 2 can generally be considered to be around 2 mm.

[0060] The construction of the above-mentioned automatic interlocking bolt external sleeve includes the installation process and the disassembly process, specifically:

[0061] 1. If Figure 1 When installing the automatic locking bolt external sleeve, insert the existing bolt 8 into the bolt hole at the bottom of the outer sleeve 1, and the top of the fork rod 6 obliquely contacts the thread of the existing bolt 8, and the retreat of the existing bolt 8 is effectively restricted.

[0062] 2. If Figure 2 After the monitoring operation is completed, the external sleeve of the automatic locking bolt can be removed, the holding lug 31 is pressed down, the unlocking slide 3 is moved downward, the fork rod circular shaft 61 moves downward, and at the same time starts to rotate. Under the limiting action of the inner spacer 2, the fork rod 6 moves obliquely downward as a whole and rotates outward around the fork rod circular shaft 61. The end of the fork rod 6 and the existing bolt 8 thread are gradually loosened, the vertical spring 51 and the oblique spring 71 are compressed at the same time, the top of the fork rod 6 is disengaged from the existing bolt 8 thread, the retreat of the existing bolt 8 is released, and the sleeve can be smoothly separated from the bolt 8.

[0063] The manufacturing process of the above-mentioned automatic locking bolt external sleeve is as follows:

[0064] S1: The dimensions of the outer sleeve 1 and its supporting structure are designed based on the diameter and length of the existing bolts 8 left after the installation of the existing underground engineering equipment. Generally, the diameter of the existing bolts 8 can be considered to be M12 to M16, and the exposed length of the existing bolts 8 can generally be considered to be approximately 3-5 cm. The cylindrical outer sleeve 1, inner spacer 2, and unlocking slide 3 are rolled from steel plates. A hole is opened at the bottom of the outer sleeve 1, and the diameter of the hole can be increased by approximately 1-2 cm based on the diameter of the existing bolts 8. A circular hole is reserved at the corresponding position of the inner spacer 2 according to the requirements for the passage of the fork rod 6. A circular hole is reserved at the corresponding position of the unlocking slide 3 according to the diameter of the fork rod circular shaft 61 at the bottom of the fork rod 6. The diameter of the circular hole must match the diameter of the fork rod circular shaft 61, and the size of the reserved circular hole section should be controlled to approximately 80% of its diameter to ensure that the fork rod circular shaft 61 can slide freely inside and will not slide out.

[0065] The thickness of the outer sleeve 1 can generally be considered to be around 3-5 mm, and the thickness of the inner spacer 2 can generally be considered to be around 2 mm.

[0066] S2: Carry out factory production of fork rod 6 and its supporting devices as required. First, according to the length and shape of fork rod 6, adopt steel bar welding to form at least 2 forks, and weld solid circular shaft at its bottom.

[0067] S3: Fabricate the spring assembly as required. Based on the circular cross-section of the spring assembly, use steel plates to fabricate the vertical spring base 54, vertical spring compartment 53, oblique spring compartment 74, spring vertical barrel 55, and the steel cover 56 and L-shaped steel plate 73 on top of the spring. Finally, assemble the vertical spring assembly 5 using the vertical spring 51, vertical rod 52, vertical spring compartment 53, spring base 54, spring vertical barrel 55, and steel cover 56. Assemble the oblique spring assembly 7 using the oblique spring 71, oblique rod 72, L-shaped steel plate 73, and oblique spring compartment 74. The spring base housing contours of the vertical and oblique spring assemblies 5 and 7 are approximately 2-3 cm larger than the outer diameter of the springs, and the vertical rod inside the springs is approximately 20 mm from the spring base.

[0068] S4: Pass the fork rod shaft 61 through the reserved circular hole on the inner spacer 2, weld and fix the bottom of the oblique spring device 7 to the fork rod 6, weld the L-shaped steel plate 73 to the inner wall of the outer sleeve 1, and then complete the fixation of the oblique spring device 7, and then press the fork rod shaft 61 into the reserved hole of the unlocking slide 3.

[0069] S5: Weld a triangular lug 31 at the upper middle position of the unlocking slide 3 as required.

[0070] S6: Weld the vertical spring device 5 to the corresponding positions on the circumference of the outer sleeve 1 as required, generally evenly distributed at about 30 degrees. When welding, weld the side of the spring base 54 at the bottom of the spring chamber 53 to the side wall of the outer sleeve 1. Then, slide the unlocking slide 3 from top to bottom on the outside of the outer sleeve 1.

[0071] S7: The measuring element 4 is effectively fixed on the top of the outer sleeve 1 by welding.

[0072] The structure of the present invention needs to pay attention to the following points:

[0073] 1. The outer diameter of the outer sleeve 1 and the inner diameter of the unlocking slide 3 need to match, and the diameter difference should be controlled within about 1mm.

[0074] 2. The vertical spring device 5 and the fork rod 6 at the bottom of the outer sleeve 1 are evenly arranged along the circumferential direction, and are spaced about 30 degrees apart. The two can be considered to be crossed and evenly distributed along the circumferential direction, and the spacing along the circumferential direction can be reduced to about 15 degrees.

[0075] 3. The distance between the vertical rod 52 in the vertical spring device 5 and the spring base 54, the displacement of the fork rod 6 diagonally downward, the distance between the diagonal rod 72 in the diagonal spring device 7 and the bottom of the diagonal spring chamber 74, and the distance between the two circles of steel plates on both sides of the diagonal spring chamber 74, which are smaller on the upper and larger on the lower, need to match each other and are generally considered to be no more than 20 mm.

[0076] 4. Since the effective engagement between the fork rod 6 and the existing bolt 8 threads provides vertical stability of the outer sleeve 1, and the engagement effect between the fork rod 6 and the existing bolt 8 threads is mainly controlled by the oblique spring device 7 and the vertical spring device 5, the initial state of the spring (before compression) must ensure that it provides sufficient "support" and "limiting" effects to the fork rod to avoid "looseness" between the top of the fork rod 6 and the existing bolt 8 threads.

[0077] The structure of the present invention has the following characteristics and advantages:

[0078] 1) Based on the concept of "elastic locking," the present invention achieves the requirement that the bolt can only move forward and not backward through the mechanical engagement between the fork rod and the bolt thread, thereby ensuring a secure connection between the outer sleeve and the bolt, meeting the needs of various inspection or monitoring tasks.

[0079] 2) The engagement between the fork rod and the bolt thread of the present invention is an "elastic locking" achieved primarily through the "elastic compression" of the spring, avoiding the potential for loosening caused by mechanical tightening between conventional bolts and nuts during long-term vibrations during underground engineering operations.

[0080] 3) Based on the concept of "flexible unlocking and reuse," this invention designs an "elastic unlocking" device that mechanically engages the fork rod and the bolt thread. This allows for the reuse of the outer sleeve and its top measuring element, effectively reducing project operation and maintenance costs.

[0081] 4) The bolt-to-sleeve device described in this invention, with its automatic locking function and its integrated functional concept of "elastic locking, flexible unlocking, and reuse," can meet the installation requirements of various detection and monitoring equipment required for the daily operation and maintenance of underground projects, while also ensuring zero damage to the underground project during the installation of measuring components. This solution, with its clear concept, simple process, and easy construction, offers high economic and social benefits, and has broad application prospects in monitoring and surveillance projects related to urban underground space development, rail transit, and railway projects.

[0082] The above examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. Those skilled in the art can make several simple deductions, modifications or substitutions based on the concept of the present invention.

Claims

1. Automatic locking bolt external sleeve, characterized by: The bolt external sleeve comprises an outer sleeve (1), an inner spacer (2) and a fork rod (6); The outer sleeve (1) has a top plate and a bottom plate, a measuring element (4) is fixed on the top of the top plate, and a bolt hole is opened in the center of the bottom plate for inserting an existing bolt (8); The inner spacer (2) is located inside the outer sleeve (1) and is coaxially arranged with the outer sleeve (1), the diameter of the inner spacer (2) is larger than the diameter of the bolt hole, the top of the inner spacer (2) is fixed to the bottom of the top plate of the outer sleeve (1), and the bottom of the inner spacer (2) is fixed to the top of the bottom plate of the outer sleeve (1); The fork rod (6) obliquely passes through the inner spacer (2) and the outer sleeve (1); a fork rod circular shaft (61) is provided at the bottom of the fork rod (6) and is located outside the outer sleeve (1); and the top of the fork rod (6) obliquely clamps the thread of the existing bolt (8); An unlocking slide cylinder (3) is provided outside the outer sleeve (1) and is coaxial with the outer sleeve (1), and the fork rod circular axis (61) is located in a rotation groove provided on the inner wall of the unlocking slide cylinder (3); The fork rod circular shaft (61) is spherical and can rotate in the rotation groove of the unlocking slide cylinder (3); An oblique spring device (7) is provided between the fork rod (6) and the outer sleeve (1); A support hole (21) is provided on the inner spacer (2), and the fork rod (6) obliquely passes through the support hole (21); The outer sleeve (1) is provided with an insertion hole, and the fork rod (6) obliquely passes through the insertion hole.

2. The automatic locking bolt external sleeve according to claim 1, characterized in that: The oblique spring device (7) comprises an oblique spring (71), an oblique rod (72), an L-shaped steel plate (73) and an oblique spring chamber (74); The oblique spring chamber (74) is fixed to the side of the fork rod (6), the L-shaped steel plate (73) is fixed to the inner wall of the outer sleeve (1), and one end of the oblique rod (72) is fixed to the L-shaped steel plate (73); The oblique spring (71) is sheathed outside the oblique rod (72) and is located in the oblique spring compartment (74), with both ends contacting the L-shaped steel plate (73) and the fork rod (6) respectively.

3. The automatic locking bolt external sleeve according to claim 2, characterized in that: A vertical spring device (5) is provided between the bottom of the unlocking slide cylinder (3) and the outer wall of the outer sleeve (1).

4. The automatic locking bolt external sleeve according to claim 3, characterized in that: The vertical spring device (5) includes a vertical spring (51), a vertical rod (52), a vertical spring chamber (53), a vertical spring base (54), a spring vertical cylinder (55) and a steel cover plate (56); The vertical spring base (54) is fixed to the outer wall of the outer sleeve (1), the spring vertical cylinder (55) is located outside the vertical spring base (54) and on the top of the vertical spring base (54), and a vertical spring chamber (53) is provided on the top surface of the vertical spring base (54); A steel cover plate (56) is provided in the spring vertical cylinder (55), the outer periphery of the steel cover plate (56) is in sliding contact with the inner wall of the spring vertical cylinder (55), and a vertical rod (52) is provided on the bottom surface of the steel cover plate (56); The vertical spring (51) is located in the spring vertical tube (55) and in the vertical spring chamber (53). The vertical spring (51) is sheathed outside the vertical rod (52), and the top and bottom are in contact with the steel cover plate (56) and the vertical spring base (54) respectively.

5. The automatic locking bolt external sleeve according to claim 4, characterized in that: The outer wall of the unlocking slide cylinder (3) is provided with a lug (31).

6. The automatic locking bolt external sleeve according to claim 5, characterized in that: The diameter of the support hole (21) is larger than the outer diameter of the fork rod (6).

7. The automatic locking bolt external sleeve according to claim 6, characterized in that: The diameter of the insertion hole is larger than the outer diameter of the fork rod (6).

8. The method for constructing an automatic locking bolt external sleeve according to claim 7, characterized in that: The method comprises: During installation, the existing bolt (8) is inserted into the bolt hole at the bottom of the outer sleeve (1), and the top of the fork rod (6) obliquely contacts the thread of the existing bolt (8), so that the retreat of the existing bolt (8) is restricted; When disassembling, press the lug (31) downward to move the unlocking slide (3), the fork rod circular shaft (61) moves downward, the vertical spring (51) and the oblique spring (71) are compressed at the same time, the fork rod (6) rotates outward around the fork rod circular shaft (61), the top of the fork rod (6) is disengaged from the thread of the existing bolt (8), and the retreat of the existing bolt (8) is released.

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