A bolt stretcher and a large nut screwing and handling device

Abstract

The present invention relates to the field of multi-functional manipulators, and specifically discloses a bolt stretcher and a large nut screwing and handling device. The device includes: a support rod; a rotating force arm capable of performing a rotating motion; a guiding rotating force arm capable of performing a swinging motion; a worm and worm gear lifting mechanism suspended on the guiding rotating force arm through a suspension bracket; a pneumatic motor driving the worm and worm gear lifting mechanism; a natural lifting and lowering mechanism arranged at the lower end of the worm and worm gear lifting mechanism; bearing end covers symmetrically arranged on both sides at the upper and lower ends of the third connecting piece; a stepped shaft connected to the third connecting piece; and a clamping manipulator fixedly connected to the lower end of the stepped shaft for clamping the bolt stretcher and the large nut. The structure of the present invention is stable, the operation is flexible, it is simple and easy to use, safe and reliable, and has a beautiful appearance. It integrates the functions of clamping, screwing and handling, has a wide stroke range, can greatly reduce the labor cost of enterprises and the labor intensity of operators, improve work efficiency, and ensure the personal safety of operators.

Description

Technical Field

[0001] The present invention relates to the field of multi-functional manipulators, and particularly to the field of semi-automatic pneumatic auxiliary manipulators during maintenance in the chemical industry. Background Art

[0002] The chemical production process has many risk factors such as high temperature, high pressure, large equipment, flammability and explosiveness. Especially during equipment maintenance, the risk coefficient is further increased. Therefore, during the maintenance process, it is necessary to avoid using tools with high risks such as fire and electricity as much as possible. When many equipment are maintained, the disassembly and assembly of covers are required, and the covers of high-pressure equipment are heavier, and the fastening nuts used on them are also increased. Conventional tools can no longer meet the disassembly and assembly of such large nuts.

[0003] With the continuous development of society and the continuous improvement of the scientific and technological level, there is currently a special tool for the disassembly and assembly of such large nuts - the bolt hydraulic tensioner. The bolt hydraulic tensioner is simply called the bolt tensioner. It relies on the hydraulic source provided by a hydraulic booster pump (ultra-high pressure oil pump). According to the tensile strength, yield coefficient and elongation rate of the material, it determines the tensile force. Using the tensile force generated by the ultra-high pressure oil pump, the bolt to which the force is applied is stretched within its elastic deformation zone, and the bolt diameter is slightly deformed, so that the nut is easily loosened, and then the disassembly and assembly of large nuts can be carried out.

[0004] With the continuous popularization of the bolt hydraulic tensioner, a new problem has arisen. Since the bolt tensioner itself is relatively heavy, and coupled with the large mass and large quantity of large nuts, during the actual operation process, the number of disassembly and handling times of the bolt tensioner and large nuts is extremely large, which makes the operators overworked. A huge amount of labor is required to complete this series of processes. The increase in the number of operators means a further increase in the risk. The use of this tool still has disadvantages such as high labor costs and high risk coefficients. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a multi-functional device that can realize the screwing, clamping and handling actions of the bolt tensioner and large nuts. This device is driven by a gas source and is easy to operate, aiming to reduce the labor cost of enterprises and the labor intensity of operators, improve work efficiency, and ensure the personal safety of operators.

[0006] To solve the above technical problem, the technical solution adopted by the present invention is: a device for screwing and handling a bolt tensioner and large nuts, comprising:

[0007] A support rod for supporting the entire device;

[0008] A rotating lever arm, with sleeves provided at its head and tail. The sleeve at its tail is concentrically and cooperatively connected to the support rod through a cylindrical pin, enabling the rotating lever arm to rotate around the support rod;

[0009] A guiding rotating lever arm, having two concentric sleeves at its tail end, which are cooperatively connected to the sleeve at the head of the rotating lever arm through a third cylindrical pin, enabling the guiding rotating lever arm to swing around the sleeve at the head of the rotating lever arm;

[0010] A worm and worm gear lifting mechanism, which is connected to a suspension bracket and is suspended on the guiding rotating lever arm through the suspension bracket;

[0011] A pneumatic motor, which is cooperatively connected to the worm and worm gear lifting mechanism through a pneumatic motor bracket and a coupling, driving the lead screw of the worm and worm gear lifting mechanism to achieve lifting motion;

[0012] A natural lifting and lowering mechanism, which includes three connecting pieces and three guiding rods, and is arranged at the lower end of the worm and worm gear lifting mechanism. The three connecting pieces are all provided with through holes for the three guiding rods to pass through to fix the three guiding rods. Among them, a through hole with a diameter larger than the diameter of the lead screw is also provided at the middle position of the first connecting piece for the lead screw to pass through. The through holes of the second connecting piece for the three guiding rods to pass through have a diameter larger than the diameter of the three guiding rods. The second connecting piece is fixed to the lead screw connecting block at the lower end of the lead screw. The third connecting piece has symmetric cavities and is arranged at the lowermost end of the natural lifting and lowering mechanism;

[0013] Bearing end covers, symmetrically arranged on both sides at the upper and lower ends of the third connecting piece;

[0014] A stepped shaft, on which two tapered roller bearings are symmetrically arranged. The two tapered roller bearings are arranged in the symmetric cavities of the third connecting piece. The bearing end covers are buckled on the upper and lower ends of the third connecting piece to connect the stepped shaft to the third connecting piece;

[0015] A clamping manipulator, which is fixedly connected to the lower end of the stepped shaft. The clamping manipulator is used to clamp a bolt stretcher and a large nut.

[0016] In some embodiments, two sleeves are provided at the tail of the rotating lever arm. The cylindrical pin includes a first cylindrical pin and a second cylindrical pin. The sleeve at the upper end of the tail of the rotating lever arm is concentrically and cooperatively connected to the upper end of the support rod through the first cylindrical pin. The sleeve at the lower end of the tail of the rotating lever arm is arranged at the tail end of the triangular bracket at the tail of the rotating lever arm and is concentrically cooperatively connected to the support piece on the side of the support rod through the second cylindrical pin.

[0017] In some embodiments, the guiding and rotating force arm includes: a channel steel and an angle steel; the angle steel is arranged above the channel steel to form a triangular shape with the channel steel for strengthening the stability of the guiding and rotating force arm; the channel steel is provided with a long rectangular through hole and two symmetrically upward grooves; the upper end of the suspension bracket is provided with four protrusions with through holes, and the protrusions are used for assembling small rollers, and the small rollers are matched with the grooves on the channel steel; the lower end of the suspension bracket is connected to the worm and worm gear lifting mechanism, wherein the lead screw of the worm and worm gear lifting mechanism passes through the long rectangular through hole of the channel steel.

[0018] In some embodiments, the two tapered roller bearings are symmetrically arranged on both sides of the shaft shoulder of the stepped shaft, and the tapered roller bearings are in interference fit with the cavity of the third connecting piece; the bearing cover at the lower end of the third connecting piece is attached to the tapered roller bearing, and there is a gap between the bearing cover at the upper end of the third connecting piece and the tapered roller bearing. The two bearing covers and the inside of the third connecting piece form a closed sealing cavity, and a grease is provided in the sealing cavity for grease lubrication of the tapered roller bearings.

[0019] In some embodiments, the lower end of the stepped shaft has a keyway and an external thread; the clamping manipulator includes: a manipulator guide frame and a manipulator claw. The guide frame includes: an upper frame body, a lower frame body, two manipulator guide rods and a reverse lead screw. One end of the reverse lead screw is provided with a hand wheel; there is a through hole and a keyway longitudinally in the middle position of the upper frame body. The lower end of the stepped shaft directly passes through the through hole of the upper frame body and is connected by a key, and a nut is used to tighten the external thread at the lower end of the stepped shaft below the upper frame body; the lower frame body is fixedly connected to the upper frame body; the two manipulator guide rods and a reverse lead screw are arranged in the lower frame body; the upper end of the manipulator claw is provided with two smooth through holes for cooperation with the manipulator guide rods, and the upper end of the manipulator claw is also provided with a threaded hole for cooperation with the reverse lead screw. The hand wheel drives the reverse lead screw to rotate, so that the manipulator claw moves towards or away from each other.

[0020] In some embodiments, the reverse lead screw is limited by a reverse lead screw fixing cover.

[0021] In some embodiments, the manipulator claw is in a hollow long strip shape, and the inner surface is made of rubber material to enhance the friction between the manipulator claw and the bolt stretcher and the large nut.

[0022] In some embodiments, a rotating support piece is arranged at the lower end of the manipulator claw to support the bolt stretcher and the large nut.

[0023] The structure of the present invention is stable, the operation is flexible, it is simple and easy to use, safe and reliable, and has a beautiful appearance. It integrates the functions of clamping, screwing and handling, has a wide stroke range, can greatly reduce the labor cost of enterprises and the labor intensity of operators, improve work efficiency, and ensure the personal safety of operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0025] Figure 2 It is a schematic diagram of the worm and worm gear lifting mechanism structure of the present invention.

[0026] Figure 3 It is a schematic diagram of the natural lifting and falling mechanism structure of the present invention.

[0027] Figure 4 It is a structural diagram of the clamping manipulator of the present invention.

[0028] Symbol description: 10 support rod; 11 first cylindrical pin; 12 second cylindrical pin; 13 third cylindrical pin; 14 rotating force arm; 15 guiding rotating force arm; 16 bolt stretcher; 21 pneumatic motor bracket; 22 suspension bracket; 23 worm and worm gear lifting mechanism; 24 pneumatic motor; 25 lead screw; 26 roller; 27 coupling; 32 first connecting piece; 33 second connecting piece; 34 third connecting piece; 35 lead screw connecting block; 36 guide rod; 40 manipulator claw; 41 stepped shaft; 42 bearing end cover; 43 tapered roller bearing; 44 upper frame body; 45 lower frame body; 46 reverse lead screw; 47 manipulator guide rod; 48 handwheel; 49 rotating support plate; 50 round nut; 51 reverse lead screw fixing cover; 52 key. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments. The drawings and specific embodiments do not limit the protection scope of the present invention.

[0030] This embodiment provides a bolt stretcher and a large nut screwing and handling device, the structure of which is as Figures 1 to 4 shown, including:

[0031] Support rod 10, fixed on the working platform, used to support the whole device, in a stepped shape;

[0032] Rotating force arm 14, with two sleeves at its tail end, can be matched with the support rod 10 through the first cylindrical pin 11 and the second cylindrical pin 12, and can perform rotational movement;

[0033] The guiding rotating lever arm 15 has two concentric sleeves at its tail end, which can be matched with the sleeves at the head of the rotating lever arm 14 through the third cylindrical pin 13, enabling the device to swing within a certain range. There is a rectangular through-hole at the lower end of this lever arm, which has a guiding effect on the components below it along the direction of this lever arm;

[0034] The worm and worm gear lifting mechanism 23 is suspended on the guiding rotating lever arm 15 through a suspension bracket 22 with four rollers, and this structure can achieve lifting movement within a certain range;

[0035] The pneumatic motor 24 is matched with the worm and worm gear lifting mechanism 23 through a pneumatic motor bracket 21 and a coupling 27;

[0036] The natural lifting and lowering mechanism includes three different connecting pieces 32, 33, 34 and three guiding rods 36, which are arranged at the lower end of the worm and worm gear lifting mechanism 23. Among them, the first connecting piece 32 is provided with regular through-holes and is matched with the three guiding rods 36. The second connecting piece 33 is roughly the same shape as the first connecting piece 32 and is fixed on the lead screw connecting block 35 at the lower end of the worm and worm gear. The third connecting piece 34 has regularly symmetric cavities and is arranged at the lowermost end of the natural lifting and lowering mechanism;

[0037] The bearing end covers 42 are symmetrically arranged on both sides of the third connecting piece 34;

[0038] The stepped shaft 41 is used to connect the power source and the clamping manipulator at its lower end. Two tapered roller bearings 43 are symmetrically arranged on it and are matched with the third connecting piece 34;

[0039] The clamping manipulator includes a manipulator guiding frame and a manipulator claw 40. The manipulator guiding frame includes upper and lower frames 44, 45, two guiding rods 47 and a reverse lead screw 46. One end of the reverse lead screw 46 is provided with a handwheel 48 and has a locking structure. The lower end of the manipulator claw 40 has a rotating support plate 49 to hold the bolt stretcher and the nut.

[0040] More specifically, in combination with Figures 1 to 4 As shown, the first cylindrical pin 11 is a hollow cylinder with external threads, and there is a sealing cap at the upper end. The rotating lever arm 14 is concentrically matched with the first cylindrical pin 11 through the cylindrical sleeve at its tail end. A round nut with internal threads is concentrically matched with the first cylindrical pin 11 and is closely attached to the upper part of the cylindrical sleeve at the tail end of the rotating lever arm 14. The second cylindrical pin 12 is in the shape of a hollow cylinder, with a sealing cap at one end and internal threads at the other end. The side support piece of the support rod 10 is provided with a through circular through-hole, which is concentrically matched with the lower end of the through-hole at the tail end of the triangular bracket at the tail end of the rotating lever arm 14. The upper end of the through-hole at the tail end of the triangular bracket at the tail end of the rotating lever arm 14 is provided with the second cylindrical pin 12, and a second cylindrical pin cover is arranged at the lower end of the second cylindrical pin 12. The third cylindrical pin 13 is in the shape of a hollow cylinder, with a sealing cap at one end and internal threads at the other end.

[0041] The guiding rotating lever arm 15 is made of improved channel steel and many angle irons. The angle irons are arranged above the channel steel to form a triangular shape with the channel steel, aiming to strengthen the stability of the guiding rotating lever arm 15 and make it more firm. At the tails of the angle irons and the channel steel, there are two concentric cylindrical sleeves, and the two concentric cylindrical sleeves are concentrically matched with the sleeve at the head of the rotating lever arm 14 and are connected by the third cylindrical pin 13 and the third cylindrical pin cover. A long rectangular through-hole is arranged at the upper end of the channel steel, and two symmetric upward grooves are arranged at the lower end.

[0042] The suspension bracket 22 is in the shape of a flat cuboid, and through-holes are arranged at all four corners. Four protrusions with through-holes are arranged at the upper end, and the protrusions are used to assemble the rollers 26. The rollers 26 are matched with the two symmetric upward grooves on the channel steel and have a certain gap, aiming to enable the suspension bracket 22 to move smoothly in the channel steel. The lower end of the suspension bracket 22 is connected to the worm and worm gear lifting mechanism 23, and the longitudinal lead screw 25 in the worm and worm gear lifting mechanism 23 passes through the long rectangular through-hole arranged at the upper end of the channel steel.

[0043] The pneumatic motor bracket 21 has the same four-corner through-holes as the suspension bracket 22 and also has corresponding through-holes for fixing the pneumatic motor 24. The pneumatic motor bracket 21 is arranged at the lower end of the worm and worm gear lifting mechanism 23, and the pneumatic motor bracket 21, the worm and worm gear lifting mechanism 23 and the pneumatic motor 24 are fixed by bolts and nuts. The coupling 27 is arranged between the output shaft of the pneumatic motor 24 and the transmission shaft of the worm and worm gear lifting mechanism 23 for transmitting power.

[0044] The first connecting piece 32 is generally triangular, and through-holes are arranged at all three corners for fixing three guide rods 36. A through-hole with a diameter larger than that of the lead screw 25 is arranged through the middle position of the first connecting piece 32. The second connecting piece 33 is generally in the same shape as the first connecting piece 32, but the diameters of the through-holes arranged at its three corners are slightly larger than the diameters of the three guide rods 36, and smooth movement can be carried out at this position. Four through-holes identical to the positions of the lead screw connecting blocks 35 at the lower end of the lead screw of the worm and worm gear lifting mechanism 23 are arranged through the second connecting piece 33, aiming to fix the second connecting piece 33 and the lead screw connecting block 35 with bolts and nuts. The third connecting piece 34 has symmetrically arranged cylindrical cavities inside and has through-holes at the same three corners as the first connecting piece 32, and is fixed at the lowermost end of the natural lifting and lowering mechanism 23.

[0045] The upper end of the stepped shaft 41 has a hexagonal joint that mates with the wrench head of the screwing wrench. The lower end has a keyway and an external thread. A pair of tapered roller bearings 43 are symmetrically arranged on both sides of the shoulder of the stepped shaft 41. The tapered roller bearings 43 are in interference fit with the cylindrical cavity of the third connecting piece 34. The bearing cover 42 is arranged on the upper and lower end faces of the third connecting piece 34 and fixed with hexagon socket head cap screws. The bearing cover 42 on the lower end face of the third connecting piece 34 is in contact with the tapered roller bearing 43. There is a small gap between the bearing cover 42 on the upper end face of the third connecting piece 34 and the tapered roller bearing 43. The two bearing covers 42 and the inside of the third connecting piece 34 form a closed sealing cavity, and grease is injected into the cavity for grease lubrication of the tapered roller bearings 43.

[0046] In the middle position of the upper frame body 44 of the guide frame, there is a large through hole and a keyway longitudinally. The lower end of the stepped shaft 41 directly penetrates the longitudinal through hole of the upper frame body 44 and is connected with a key 52. A round nut 50 is used to tighten the external thread at the lower end of the stepped shaft 41 under the upper frame body 44. Through holes are respectively arranged at both ends of the upper frame body 44. The lower frame body 45 is provided with through holes connected to the upper frame body 44 and is connected with bolts and nuts. Two manipulator guide rods 47 and a reverse lead screw 46 are arranged inside the lower frame body 45. The reverse lead screw 46 is axially limited by a reverse lead screw fixing cover 51. One end of the reverse lead screw 46 is connected with a handwheel 48. The manipulator claw 40 is in a hollow long strip shape, and the inner surface is made of rubber material, which can greatly enhance the friction between the manipulator claw 40 and the bolt stretcher 16 and the large nut under a certain clamping force. Two smooth through holes are arranged at the upper end of the manipulator claw 40 to cooperate with the manipulator guide rods 47 in the lower frame body 45. A threaded hole is arranged at the upper end of the manipulator claw 40 to cooperate with the reverse lead screw 46 in the lower frame body 45. The reverse lead screw 46 can make the manipulator claw 40 move towards or away from each other. A rotating support piece 49 is arranged at the lower end of the manipulator claw 40 to support the bolt stretcher and the nut.

[0047] In the specific disassembly of the nut in this embodiment, the steps include:

[0048] (1) Fix the support frame 10 on the working platform, and drag the manipulator claw 40 above the bolt stretcher 16. During this period, the rotating lever 14 will rotate with the support frame 10, the guiding rotating lever 15 will rotate with the rotating lever 14, and the suspension bracket 22 and its components will move linearly along the guiding rotating lever 15.

[0049] (2) Move the manipulator claw 40 downward to surround the bolt stretcher 16. During this period, the pneumatic motor 24 rotates, and the power is transmitted to the worm and gear lifting mechanism 23 through the coupling 27, and then the lead screw 25 descends, causing the clamping manipulator claw to descend.

[0050] (3) Turn the hand wheel 48. Under the action of the reverse screw 46, the two mechanical claws 40 move toward each other until they clamp the bolt tensioner 16. Press the locking end of the rotating support 49 to drag the bolt tensioner 16. The mechanical claws 40 and the bolt tensioner 16 are firmly fixed.

[0051] (4) Control the device to move the bolt tensioner 16 to the upper end of the bolt to align the bolt. During this period, the rotating lever arm 14 will rotate with the support frame 10, the guide rotating lever arm 15 will rotate with the rotating lever arm 14, and the suspension bracket 22 and its components will move linearly along the guide rotating lever arm 15;

[0052] (5) Control the pneumatic motor 24 to make the second connecting piece 33 continue to move downward until the distance between the lead screw connecting block 35 and the hexagonal joint on the lower stepped shaft 41 is about 20 cm and the second connecting piece 33 stops moving. Use a pneumatic wrench to connect the hexagonal joint on the stepped shaft 41 and tighten it until the bolt tensioner 16 is tightened to the bottom of the bolt platform and stops moving.

[0053] (6) The bolt tensioner 16 uses the hydraulic source provided by the hydraulic booster pump (ultra-high pressure oil pump) and the tensile force generated by the ultra-high pressure oil pump to stretch the bolt to which force is applied in its elastic deformation zone, causing the bolt diameter to deform slightly, thereby loosening the nut;

[0054] (7) Use a pneumatic wrench to tighten the hexagonal joint on the stepped shaft 41 until the bottom of the bolt tensioner 16 is separated from the upper end of the bolt. During this period, the third connecting piece 34 will be forced to move upward naturally;

[0055] (8) Move the bolt tensioner 16 to the root of another bolt, i.e. repeat steps (4) and (5);

[0056] (9) Press the loose end of the rotating support 49 to release the clamping force of the clamping manipulator on the bolt tensioner;

[0057] (10) Use the device to repeat actions (1), (2), (3), (7) to remove the large nut, wherein the target of action is changed from the bolt tensioner 16 to the large nut;

[0058] (11) After the device is controlled to move the large nut to the specified position, the rotating support 49 is pressed to release the end, thereby releasing the clamping force of the clamping manipulator on the large nut, thereby completing the entire process of nut removal.

[0059] The advantages of the present invention are: stable structure, flexible operation, ease of use, safety and reliability, beautiful appearance, integration of clamping, screwing and carrying functions, wide travel range, which can greatly reduce the labor cost of the enterprise and the labor intensity of the operators, improve work efficiency, and ensure the personal safety of the operators.

[0060] The above-described embodiments are merely preferred embodiments cited to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art based on the present invention are all within the protection scope of the present invention.

Claims

1. A bolt stretcher and a large nut screwing and handling device, characterized in that, comprising: a support rod for supporting the entire device; a rotating lever arm with sleeves at its head and tail, and the sleeve at its tail is concentrically and cooperatively connected to the support rod by a cylindrical pin, so that the rotating lever arm can rotate around the support rod; a guiding rotating lever arm with two concentric sleeves at its tail end, which is cooperatively connected with the sleeve at the head of the rotating lever arm through a third cylindrical pin, so that the guiding rotating lever arm can swing around the sleeve at the head of the rotating lever arm; a worm and worm gear lifting mechanism, which is connected to a suspension bracket and is suspended on the guiding rotating lever arm through the suspension bracket; a pneumatic motor, which is cooperatively connected with the worm and worm gear lifting mechanism through a pneumatic motor bracket and a coupling, and drives the lead screw of the worm and worm gear lifting mechanism to achieve lifting movement; a natural lifting and lowering mechanism, which includes three connecting pieces and three guiding rods, and is arranged at the lower end of the worm and worm gear lifting mechanism. The three connecting pieces are all provided with through holes for the three guiding rods to pass through to fix the three guiding rods. Among them, a through hole with a diameter larger than the diameter of the lead screw is also provided at the middle position of the first connecting piece for the lead screw to pass through. The through holes of the second connecting piece for the three guiding rods to pass through have a diameter larger than the diameter of the three guiding rods. The second connecting piece is fixed on the lead screw connecting block at the lower end of the lead screw. The third connecting piece has symmetrical cavities and is arranged at the lowermost end of the natural lifting and lowering mechanism; bearing end covers, symmetrically arranged on both sides of the upper end and the lower end of the third connecting piece; a stepped shaft, on which two tapered roller bearings are symmetrically arranged. The two tapered roller bearings are arranged in the symmetric cavities of the third connecting piece, and the bearing end covers are buckled on the upper end and the lower end of the third connecting piece to connect the stepped shaft and the third connecting piece; a clamping manipulator, which is fixedly connected to the lower end of the stepped shaft. The clamping manipulator is used to clamp the bolt stretcher and the large nut. The clamping manipulator includes: a manipulator guiding frame and manipulator claws; the manipulator claws are in a hollow long strip shape, and the inner surface is made of rubber material to enhance the friction between the manipulator claws and the bolt stretcher and the large nut; a rotating support plate is arranged at the lower end of the manipulator claws to support the bolt stretcher and the large nut.

2. The bolt stretcher and the large nut screwing and handling device according to claim 1, characterized in that, two sleeves are provided at the tail of the rotating lever arm, and the cylindrical pin includes a first cylindrical pin and a second cylindrical pin; the sleeve at the upper end of the tail of the rotating lever arm is concentrically and cooperatively connected to the upper end of the support rod by the first cylindrical pin; the sleeve at the lower end of the tail of the rotating lever arm is arranged at the tail end of the triangular bracket at the tail of the rotating lever arm and is concentrically cooperated with the support piece on the side of the support rod through the second cylindrical pin.

3. The bolt stretcher and the large nut screwing and handling device according to claim 1, characterized in that, the guiding rotating lever arm includes: a channel steel and an angle iron; the angle iron is arranged above the channel steel and forms a triangular shape with the channel steel to strengthen the stability of the guiding rotating lever arm; the channel steel is provided with a long rectangular through hole and two symmetric upward grooves; Four protrusions with through holes are provided at the upper end of the suspension bracket. The protrusions are used to assemble small rollers, and the small rollers are matched with the grooves on the channel steel. The lower end of the suspension bracket is connected to the worm and worm gear lifting mechanism, and the lead screw of the worm and worm gear lifting mechanism passes through the long rectangular through hole of the channel steel.

4. A bolt stretcher and a large nut screwing and handling device according to claim 1, characterized in that The two tapered roller bearings are symmetrically arranged on both sides of the shaft shoulder of the stepped shaft, and the tapered roller bearings are in interference fit with the cavity of the third connecting piece; The bearing cover at the lower end of the third connecting piece is in contact with the tapered roller bearing, and a gap is left between the bearing cover at the upper end of the third connecting piece and the tapered roller bearing. The two bearing covers and the inside of the third connecting piece form a closed sealing cavity, and grease is provided in the sealing cavity for grease lubrication of the tapered roller bearings.

5. A bolt stretcher and a large nut screwing and handling device according to claim 1, 2, 3 or 4, characterized in that A keyway and an external thread are provided at the lower end of the stepped shaft; The guide frame includes an upper frame body, a lower frame body, two manipulator guide rods and a reverse lead screw, and a handwheel is arranged at one end of the reverse lead screw; A through hole and a keyway are longitudinally arranged in the middle position of the upper frame body. The lower end of the stepped shaft directly passes through the through hole of the upper frame body and is connected by a key, and a nut is used to tighten the external thread at the lower end of the stepped shaft below the upper frame body; The lower frame body is fixedly connected to the upper frame body; The two manipulator guide rods and a reverse lead screw are arranged in the lower frame body; Two smooth through holes are provided at the upper end of the manipulator claw and are matched with the manipulator guide rods. A threaded hole is also provided at the upper end of the manipulator claw and is matched with the reverse lead screw. The handwheel drives the reverse lead screw to rotate, so that the manipulator claw moves towards or away from each other.

6. A bolt stretcher and a large nut screwing and handling device according to claim 5, characterized in that The reverse lead screw is limited by a reverse lead screw fixed cover.

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