Pneumatic bolt tensioner with accurate pre-tightening force

Abstract

The pneumatic bolt tensioner comprises a supporting sleeve, a high-pressure air cylinder and a stretching piece, the stretching piece comprises a stretching bolt and a stretching nut, an observation window is arranged at the bottom of the side face of the supporting sleeve, the width of the observation window is larger than the distance between adjacent shifting rods, and a piston at the top of the high-pressure air cylinder abuts against the head of the stretching bolt. The stretching nut is a round nut, a lower connecting column is arranged at the bottom of the high-pressure air cylinder, a lower connecting hole is formed in the top of the supporting sleeve, the lower connecting column is in transition fit with the lower connecting hole, the thread hardness of the stretching nut is larger than that of the stretched screw, and the thread hardness of the stretching nut is smaller than that of the stretching bolt. The round nut is used as the stretching nut, the strength is high, the thread hardness of the stretching nut is lower than that of a stretching bolt, only the stretching nut needs to be replaced during replacement, the maintenance cost is reduced, the high-pressure air cylinder and the supporting sleeve are assembled in a transition fit mode, assembling is easy, the structure is simple, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The utility model relates to a bolt and nut installation tool, in particular to a pneumatic bolt stretcher with accurate pre-tightening force. Background Art

[0002] At present, on the wind power installation and fastening site, during the process of assembling and tightening the flange bolts, for the flanges with high sealing requirements, the general method is to use a hydraulic wrench to perform multiple stepped pre-tightening on the bolt and nut. Although the effect of this method meets the requirements of the pre-tightening force, the efficiency is low and the labor intensity is high. There are also screw stretchers used to solve the above problems, but the existing screw stretchers have complex structures, resulting in high manufacturing costs and high maintenance costs. Content of the Utility Model

[0003] Aiming at the deficiencies of the prior art, the purpose of the utility model is to provide a pneumatic bolt stretcher tool with accurate pre-tightening force.

[0004] The technical solution adopted by the utility model to solve its technical problems is: a pneumatic bolt stretcher with accurate pre-tightening force, including a support sleeve, a high-pressure cylinder arranged at the top of the support sleeve, and a stretching member connected to the high-pressure cylinder. The stretching member includes a stretching bolt and a stretching nut threadedly engaged with the stretching bolt. The thread of the stretching nut that is not engaged with the stretching bolt is used to threadedly engage with the stretched screw. An observation window is arranged at the bottom of the side of the support sleeve, and the width of the observation window is greater than the distance between adjacent shift rods. The piston at the top of the high-pressure cylinder abuts against the head of the stretching bolt. The stretching nut is a round nut. A lower connecting column is arranged at the bottom of the high-pressure cylinder, and a lower connecting hole is arranged at the top of the support sleeve. The lower connecting column and the lower connecting hole are in transitional fit. The thread hardness of the stretching nut is greater than the thread hardness of the stretched screw, and the thread hardness of the stretching nut is less than the thread hardness of the stretching bolt.

[0005] As a further improvement of this design, a limiting ring is detachably connected to the top of the high-pressure cylinder. A washer is arranged inside the inner ring of the limiting ring, and the top of the washer abuts against the head of the stretching bolt.

[0006] As a further improvement of this design, an upper connecting column is arranged at the bottom of the limiting ring, and an upper connecting hole is arranged at the top of the high-pressure cylinder. The upper connecting column and the upper connecting hole are in transitional fit.

[0007] As a further improvement of this design, a disassembly notch is arranged at the bottom of the limiting ring to facilitate the insertion of a disassembly tool.

[0008] As a further improvement of this design, an air pressure groove extending annularly along the bottom of the piston is arranged at the bottom of the piston. An air inlet and outlet hole extending to the air pressure groove is arranged on the shell of the high-pressure cylinder. Sealing rings are arranged on both the inner and outer walls of the piston.

[0009] As a further improvement of this design, a torsion groove extending along the generatrix direction is provided on the outer periphery of the head of the tension bolt, and an internal hexagonal hole facilitating docking with an internal hexagonal wrench is provided at the top end of the head of the tension bolt.

[0010] As a further improvement of this design, an adsorption magnet is provided at the bottom of the internal hexagonal hole.

[0011] As a further improvement of this design, an internal pin hole is provided on the side surface of the tension bolt, an external pin hole is provided on the tension nut, and a pin body is connected between the tension bolt and the tension bolt, and the pin body penetrates through the external pin hole and the internal pin hole.

[0012] As a further improvement of this design, the internal pin hole is an oval hole and the length direction of the oval hole is along the generatrix direction of the threaded surface of the tension bolt.

[0013] As a further improvement of this design, the bottom of the tension nut is lower than the top of the observation window.

[0014] The beneficial effects of the present utility model are as follows: The present utility model uses a round nut as the tension nut with high strength. Since the thread hardness of the tension nut is lower than that of the tension bolt, only the tension nut needs to be replaced during replacement, reducing the maintenance cost. The high-pressure cylinder and the support sleeve are assembled by an interference fit method, with simple assembly, simple structure, reduced manufacturing cost, and each component being easy to maintain, thereby ensuring accurate pre-tightening force. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0016] Figure 1 is a three-dimensional structural schematic diagram of the present utility model.

[0017] Figure 2 is an overall sectional schematic diagram of the present utility model.

[0018] Figure 3 is a three-dimensional schematic diagram of the working state of the present utility model.

[0019] Figure 4 is an overall sectional schematic diagram of the working state of the present utility model.

[0020] In the figure, 1. support sleeve, 2. stretching member, 20. stretching bolt, 20. torsion groove, 21. stretching nut, 3. high-pressure cylinder, 4. observation window, 5. limit ring, 6. washer, 7. upper connecting column, 8. upper connecting hole, 9. lower connecting column, 10. lower connecting hole, 11. external pin hole, 12. pin body, 13. piston, 14. air pressure groove, 15. adsorption magnet, 16. internal hexagonal hole, 17. disassembly notch, 18. air inlet and outlet hole, 19. internal pin hole, 300. flange, 301. stretched screw rod, 302. lever, 303. fastening nut, 304. internal hexagonal wrench. Detailed implementation mode

[0021] The present utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments, in which the schematic embodiments and descriptions are only used to explain the present utility model, but not to limit the present utility model.

[0022] Embodiment: A pneumatic bolt stretcher with precise pre-tightening force, comprising a support sleeve 1, a high-pressure cylinder 3 arranged at the top of the support sleeve 1, and a stretching member 2 connected to the high-pressure cylinder 3. The stretching member 2 includes a stretching bolt 20 and a stretching nut 21 threadedly engaged with the stretching bolt 20. The thread of the stretching nut 21 that is not engaged with the stretching bolt 20 is used to threadedly engage with the stretched screw rod 301. An observation window 4 is provided at the bottom of the side of the support sleeve 1, and the width of the observation window 4 is greater than the distance between adjacent levers 302. The piston 13 at the top of the high-pressure cylinder 3 abuts against the head of the stretching bolt 20. The stretching nut 21 is a round nut. A lower connecting column 9 is provided at the bottom of the high-pressure cylinder 3, and a lower connecting hole 10 is provided at the top of the support sleeve 1. The lower connecting column 9 and the lower connecting hole 10 are in transitional fit. The thread hardness of the stretching nut 21 is greater than the thread hardness of the stretched screw rod 301, effectively stretching the stretched bolt 301. The thread hardness of the stretching nut 21 is less than the thread hardness of the stretching bolt 20, reducing the damage of the stretching screw rod 20.

[0023] Using a round nut as the stretching nut 21 has high strength. Since the thread hardness of the stretching nut 21 is lower than that of the stretching bolt 20, only the stretching nut 21 needs to be replaced during replacement, reducing the maintenance cost. The high-pressure cylinder 3 and the support sleeve 1 are assembled by means of transitional fit, with simple assembly and simple structure, reducing the manufacturing cost.

[0024] Please refer to Figure 2 , a limit ring 5 is detachably connected to the top of the high-pressure cylinder 3 to limit the washer 6, facilitating the replacement of the washer 6 and reducing the replacement cost. A washer 6 is provided in the inner circle of the limit ring 5, and the top of the washer 6 abuts against the head of the stretching bolt 20 for evenly distributing the pressure.

[0025] Please refer to Figure 2, a upper connecting post 7 is provided at the bottom of the limit ring 5, and an upper connecting hole 8 is provided at the top of the high-pressure cylinder 3. The upper connecting post 7 and the upper connecting hole 8 are in transitional fit to simplify disassembly, assembly and structure.

[0026] Please refer to Figure 1 , a disassembly notch 17 for inserting a disassembly tool is provided at the bottom of the limit ring 5, so that the limit ring 5 is convenient for disassembly and assembly.

[0027] Please refer to Figure 2 , an air pressure groove 14 extending annularly along the bottom of the piston 13 is provided at the bottom of the piston 13 to reduce the structure of the high-pressure cylinder 3, thereby reducing the volume of the high-pressure cylinder 3. At the same time, the piston 13 is initially balanced and not prone to deflection when receiving force, and the piston 13 moves up and down smoothly. An air inlet and outlet hole 18 extending to the air pressure groove 14 is provided on the housing of the high-pressure cylinder 3, and sealing rings are provided on both the inner and outer walls of the piston 13.

[0028] Please refer to Figure 1 , a torsion groove 20 extending along the generatrix direction is provided on the outer circumference of the head of the tension bolt 20, which is convenient for a round nut wrench to rotate the tension bolt 20. An inner hexagonal hole 16 convenient for docking with an inner hexagonal wrench 304 is provided at the top end of the head of the tension bolt 20.

[0029] Please refer to Figure 2 , an adsorption magnet 15 is provided at the bottom of the inner hexagonal hole 16, which is convenient for adsorbing the inner hexagonal wrench 304 to prevent the inner hexagonal wrench 304 from coming out during use.

[0030] Please refer to Figure 2 , an inner pin hole 19 is provided on the side of the tension bolt 20, an outer pin hole 11 is provided on the tension nut 21, and a pin body 12 is connected between the tension bolt 20 and the tension bolt 20. The pin body 12 penetrates through the outer pin hole 11 and the inner pin hole 19.

[0031] Please refer to Figure 2 , the inner pin hole 19 is an oval hole, and the length direction of the oval hole is along the generatrix direction of the threaded surface of the tension bolt 20.

[0032] Please refer to Figure 2 , the bottom of the tension nut 21 is lower than the top of the observation window 4, which is convenient for adjusting the meshing length between the tension nut 21 and the tension bolt 20.

[0033] During operation, please refer to Figure 3 and Figure 4, the stretched screw 301 and the fastening nut 303 clamp the flange 300. The support sleeve 1 is sleeved on the stretched screw 301. Rotate the stretching bolt 20, and then drive the stretching nut 21 to rotate. The stretching nut 21 is threadedly engaged with the stretched screw 301 until the required length. Inject high-pressure air with a set pressure into the air inlet and outlet hole 18. Insert the lever 302 into the hole on the side of the fastening nut 303 and turn the nut to the set torque value. Release the high-pressure air from the air inlet and outlet hole. Rotate the stretching bolt 20 and screw out the stretching nut 21 from the stretched screw 301.

[0034] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A pneumatic bolt tensioner with precise preload, characterized in that: It includes a support sleeve, a high-pressure cylinder arranged on the top of the support sleeve, and a stretching part connected to the high-pressure cylinder, the stretching part includes a stretching bolt and a stretching nut threadedly matched with the stretching bolt, the thread of the stretching nut not matched with the stretching bolt is used to match with the thread of the stretched screw rod, an observation window is provided at the bottom of the side of the support sleeve, the width of the observation window is greater than the distance between adjacent levers, the piston at the top of the high-pressure cylinder abuts the head of the stretching bolt, the stretching nut is a round nut, a lower connecting column is provided at the bottom of the high-pressure cylinder, a lower connecting hole is provided at the top of the support sleeve, the lower connecting column is transitionally matched with the lower connecting hole, the thread hardness of the stretching nut is greater than the thread hardness of the stretched screw rod, and the thread hardness of the stretching nut is less than the thread hardness of the stretching bolt.

2. A pneumatic bolt tensioner with precise preload according to claim 1, characterized in that: The top of the high-pressure cylinder is detachably connected to a limiting ring, an inner ring of the limiting ring is provided with a washer, and the top of the washer abuts against the head of the stretching bolt.

3. A pneumatic bolt tensioner with precise preload according to claim 2, characterized in that: An upper connecting column is provided at the bottom of the limiting ring, and an upper connecting hole is provided at the top of the high-pressure cylinder. The upper connecting column and the upper connecting hole are transitionally matched.

4. A pneumatic bolt tensioner with precise preload according to claim 3, characterized in that: A disassembly notch is provided at the bottom of the limiting ring for easy insertion of a disassembly tool.

5. The pneumatic bolt tensioner with precise preload according to claim 1, characterized in that: The bottom of the piston is provided with an air pressure groove extending in an annular manner along the bottom of the piston, the shell of the high-pressure cylinder is provided with air inlet and outlet holes extending to the air pressure groove, and the inner and outer walls of the piston are both provided with sealing rings.

6. The pneumatic bolt tensioner with precise preload according to claim 1, characterized in that: The outer periphery of the stretch bolt head is provided with a torsion groove extending along the generatrix direction thereof, and the top end of the stretch bolt head is provided with an inner hexagon hole for easy docking with an inner hexagon wrench.

7. A pneumatic bolt tensioner with precise preload according to claim 6, characterized in that: An adsorption magnet is arranged at the bottom of the inner hexagonal hole.

8. The pneumatic bolt tensioner with precise preload according to claim 1, characterized in that: An inner pin hole is provided on the side of the stretch bolt, an outer pin hole is provided on the stretch nut, a pin body is connected between the stretch bolt and the stretch bolt, and the pin body passes through the outer pin hole and the inner pin hole.

9. A pneumatic bolt tensioner with precise preload according to claim 8, characterized in that: The inner pin hole is a waisted hole and the length direction of the waisted hole is along the generatrix direction of the thread surface of the tension bolt.

10. The pneumatic bolt tensioner with precise preload according to claim 8, characterized in that: The bottom of the stretching nut is lower than the top of the observation window.

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