A tool for taking off a broken bolt

Abstract

This invention relates to the field of broken bolt removal devices, specifically to a tooling for removing broken bolts. The invention includes a housing with a limiting plate slidably connected to its exterior. A ring-drilling cutter is rotatably connected to one end of the housing, and a hollow shaft motor is fixedly connected to the housing. The ring-drilling cutter, driven by the hollow shaft motor, cuts an annular groove into the broken bolt. It also includes a round bar. A mating hole is formed in the center of the ring-drilling cutter, and several mating keys are fixedly connected to the inner side of the mating hole. A mating groove is formed on the round bar, and the mating keys cooperate with the mating groove to transmit rotation. A first telescopic rod is provided on the side of the housing away from the ring-drilling cutter. A base is fixedly connected to the end of the first telescopic rod away from the housing, and a clamp is rotatably connected to the base for clamping and fixing the round bar. Using the technical solution of this invention, an annular groove is cut into the broken bolt by the ring-drilling cutter, and then the round bar is frictionally welded to the broken bolt, allowing subsequent rotation of the round bar to unscrew the broken bolt.

Description

Technical Field

[0001] This invention relates to the field of broken bolt removal devices, and more specifically, to a tooling for removing broken bolts. Background Technology

[0002] Wind turbine generators consist of basic components such as rotors, nacelles, and towers. The generator uses wind power to drive the rotor, converting wind energy into mechanical energy. The generator then converts this mechanical energy into electrical energy, which is transmitted through collection lines to the wind farm's substation, where it is boosted and then fed into the power grid. Due to prolonged exposure to harsh outdoor environments, the bolts on wind turbine generators gradually corrode, particularly the bolts connecting the pitch slewing bearing and the blades. Corrosion often leads to breakage. Because the bolts are coated with molybdenum disulfide to improve their wear resistance, corrosion resistance, high-temperature resistance, and sealing performance, ensuring a tight and stable connection, it is even more difficult to remove broken bolts.

[0003] Existing technologies include two methods for removing broken bolts: the broken bolt extractor method and the welding method. The broken bolt extractor method involves punching a hole in the center of the broken bolt, drilling a hole with a center drill bit (the drill bit's outer diameter must be smaller than the bolt's inner diameter), then replacing it with a larger drill bit and continuing drilling. The broken bolt extractor is then hammered into the hole and rotated counterclockwise until most of the bolt is unscrewed, and then it is unscrewed by hand. In this method, drilling is done in two stages because drilling in one go involves a large cutting amount, which can easily cause the drill bit to deviate or wobble. The welding method does not require drilling, but when the bolt breaks inside a bolt hole, the limited space makes welding extremely difficult.

[0004] Friction welding is a method of welding metal parts by causing them to heat up to a molten state through rotational friction. It produces precise welds and does not require a welding torch, making it suitable for welding inside bolt holes. However, because the bolt and bolt hole are in contact, if the molten state causes the bolt and bolt hole to stick together, it becomes more difficult to remove the bolt. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a tooling for removing broken bolts. It involves using a ring-cutting tool to cut an annular groove on the broken bolt, and then using a round bar to frictionally weld the broken bolt to the round bolt, so that subsequent rotation of the round bar can unscrew the broken bolt.

[0006] This invention is achieved through the following technical solution: a tooling for removing broken bolts, comprising a housing, with a limit plate slidably connected to the outside of the housing;

[0007] A ring-drilling cutter is rotatably connected to one end of the housing, and a hollow shaft motor is fixedly connected to the housing. The hollow shaft motor is used to drive the ring-drilling cutter to rotate, and the ring-drilling cutter is used to cut an annular groove on the broken bolt under the drive of the hollow shaft motor.

[0008] It also includes a round bar, a mating hole is provided in the middle of the ring digging cutter, and several mating keys are fixedly connected to the inner side of the mating hole. A mating groove is provided on the round bar, and the mating key is used to cooperate with the mating groove to transmit rotation. A first telescopic rod is provided on the side of the housing away from the ring digging cutter. A base is fixedly connected to the end of the first telescopic rod away from the housing. A clamp is rotatably connected to the base, and the clamp is used to clamp and fix the round bar.

[0009] Furthermore, a dust suction port is connected to the base, and a vacuum cleaner is connected to the dust suction port. The vacuum cleaner is used to remove metal shavings cut by the ring-drilling tool.

[0010] Furthermore, a fixing ring is provided on the outer side of the base, and the fixing ring has several mounting holes, with locking holes for mounting bolts.

[0011] Furthermore, the clamp includes a ring body with a detachable cover on the inner side of the ring body. A fastening frame is provided on the side of the ring body away from the ring digging tool. A through hole is provided on the round bar. A bolt is slidably connected to the fastening frame. A nut is detachably connected to the bolt. The bolt is used to pass through the through hole to fix the round bar.

[0012] Furthermore, a support platform is fixedly connected to the top of the limiting plate, and a second telescopic rod is fixedly connected to the support platform. The second telescopic rod is used to drive the housing to slide.

[0013] Furthermore, an adjustment airbag is provided on the outside of the limiting plate, which is used to inflate and adjust the position of the limiting plate.

[0014] Furthermore, the limiting plate is equipped with a cooling lubricant release head, which is used to spray cooling lubricant onto the threads of the broken bolt.

[0015] Furthermore, it also includes a bar-shaped cutter, which is used to cooperate with the mating key to transmit rotation, and the bar-shaped cutter is used to grind the central cylinder of the annular groove.

[0016] Furthermore, the bottom of the round bar has a rough surface.

[0017] Furthermore, a power-assisted handle is detachably connected via a through-hole.

[0018] The technical solution of the present invention has at least the following beneficial effects:

[0019] This solution is used to remove the connecting bolts between the pitch slewing bearing and the blades. When using it, first insert the limiting plate into the threaded hole where the broken bolt is located. The limiting plate provides support and aligns the circumferential cutting tool with the center of the broken bolt.

[0020] Start the hollow shaft motor to drive the ring cutting tool to rotate and push the housing towards the broken bolt. The ring cutting tool will cut an annular groove on the broken bolt. The center of the annular groove will be cut to leave a cylinder for subsequent friction welding of the round bar.

[0021] The round bar is assembled onto the holder, passing through the hollow shaft motor and the ring-drilling cutter, extending to the side of the ring-drilling cutter near the broken bolt. This ensures that after the housing is pushed, only the round bar contacts the central cylinder of the annular groove. The ring-drilling cutter has a mating key that enables rotational transmission; therefore, the hollow shaft motor driving the ring-drilling cutter rotates the round bar. Under the action of the rotating round bar and the applied thrust, the round bar rubs against the central cylinder of the annular groove, generating heat and entering a molten state, causing the round bar to bond with the central cylinder of the annular groove, forming a weld point. During this process, the annular groove provides heat insulation, concentrating the heat at the central cylinder of the annular groove, preventing the heat generated by friction from melting the threads of the broken bolt and causing it to bond to the threaded hole.

[0022] After the friction welding between the round bar and the broken bolt is completed, the clamp releases the round bar, disengaging the housing from the threaded hole. The round bar will remain on the broken bolt. The user can rotate the round bar in the threaded hole to make the broken bolt rotate and remove it. Attached Figure Description

[0023] Figure 1 This is an isometric schematic diagram of an embodiment of the tooling for removing broken bolts according to the present invention;

[0024] Figure 2 This is a front view schematic diagram of an embodiment of the tooling for removing broken bolts according to the present invention;

[0025] Figure 3 This is a side view schematic diagram of an embodiment of the tooling for removing broken bolts according to the present invention;

[0026] Figure 4 This is a top view schematic diagram of an embodiment of the tooling for removing broken bolts according to the present invention;

[0027] Figure 5 This is a cross-sectional schematic diagram of an embodiment of the tooling for removing broken bolts according to the present invention;

[0028] Figure 6 This is a cross-sectional schematic diagram of the tooling embodiment for removing broken bolts according to the present invention during operation;

[0029] Figure 7 This is a schematic diagram of the installation of the assist handle after welding is completed in an embodiment of the tooling for removing broken bolts according to the present invention.

[0030] Reference numerals: 1. Housing; 2. Limiting plate; 3. Ring excavation cutter; 4. Hollow shaft motor; 5. Annular groove; 6. Round bar; 7. Matching hole; 8. Matching key; 9. First telescopic rod; 10. Base; 11. Clamp; 12. Dust suction port; 13. Dust collector; 14. Fixing ring; 15. Mounting bolt; 16. Support platform; 17. Second telescopic rod; 18. Adjusting airbag; 19. Coolant / lubricant release head; 20. Power handle; 601. Through hole; 602. Matching groove; 1101. Ring body; 1102. Fastening frame; 1103. Bolt body; 1104. Nut. Detailed Implementation

[0031] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] The following detailed description illustrates the specific implementation method:

[0035] Example 1

[0036] As attached Figures 1-7 As shown, a tooling for removing broken bolts includes a housing 1, with a limiting plate 2 slidably connected to the outside of the housing 1.

[0037] A ring-drilling cutter 3 is rotatably connected to one end of the housing 1. A hollow shaft motor 4 is bolted to the housing 1. The hollow shaft motor 4 is used to drive the ring-drilling cutter 3 to rotate. The ring-drilling cutter 3 is used to cut an annular groove 5 on the broken bolt under the drive of the hollow shaft motor 4.

[0038] It also includes a round bar 6, a mating hole 7 is provided in the middle of the ring digging cutter 3, and a number of mating keys 8 are integrally formed inside the mating hole 7. A mating groove 602 is provided on the round bar 6. The mating key 8 is used to cooperate with the mating groove 602 to transmit rotation. A first telescopic rod 9 is provided on the side of the housing 1 away from the ring digging cutter 3. The first telescopic rod 9 is a telescopic sleeve rod. A seat 10 is bolted to the end of the first telescopic rod 9 away from the housing 1. A clamp 11 is rotatably connected to the seat 10. The clamp 11 is used to clamp and fix the round bar 6.

[0039] The base 10 has a dust suction port 12 connected to it, and the dust suction port 12 is connected to a vacuum cleaner 13, which is used to collect the metal shavings cut by the ring-drilling tool 3. A fixing ring 14 is provided on the outer side of the base 10, and the fixing ring 14 has several mounting holes, with locking holes for mounting bolts 15. The clamp 11 includes a ring body 1101, with a detachable cover connected to the inner side of the ring body 1101. A fastening frame 1102 is provided on the side of the ring body 1101 away from the ring-drilling tool 3. A through hole 601 is opened on the round bar 6, and a bolt body 1103 is slidably connected to the fastening frame 1102. A nut 1104 is detachably connected to the bolt body 1103, which is used to pass through the through hole 601 to fix the round bar 6.

[0040] This solution is used to remove the connecting bolts between the pitch slewing bearing and the blades. The connecting bolts are usually M30, M33, and M36, which are relatively large in size. Therefore, they require more kinetic energy to drive their rotation, and the connection strength between the auxiliary structure and the broken bolts is required to be higher.

[0041] In use, the limiting plate 2 is first inserted into the threaded hole containing the broken bolt. The limiting plate 2 provides support and aligns the ring-drilling cutter 3 with the center of the broken bolt, so that the round bar 6 to be welded later can be concentric with the broken bolt, so as to transmit the rotational driving force.

[0042] The hollow shaft motor 4 is activated. Its hollow structure allows objects to pass directly through the shaft, facilitating the subsequent insertion of the round bar 6. The hollow shaft motor 4 drives the ring-cutting cutter 3 to rotate. The user pushes the housing 1 towards the broken bolt, causing the ring-cutting cutter 3 to cut an annular groove 5 into the bolt. A cylinder is left at the center of the annular groove 5 for subsequent friction welding of the round bar 6. After the angled cut, metal debris remains in the threaded hole, hindering subsequent welding operations. Therefore, a suction port 12 and a vacuum cleaner 13 are provided. The vacuum cleaner 13 can suck up the cut metal debris through the hollow shaft of the hollow shaft motor 4, cleaning the threaded hole without removing the housing 1, eliminating the need for repositioning in subsequent operations. The base 10 can be pulled open via the first telescopic rod 9 for internal cleaning, preventing further metal debris from affecting transmission and engagement.

[0043] After the cutting is completed, the ring digging cutter 3 is retracted, the seat 10 is pulled open, and the round bar 6 is assembled onto the clamp 11. The round bar 6 will pass through the hollow shaft motor 4 and the ring digging cutter 3 and extend to the side of the ring digging cutter 3 near the broken bolt. In this way, after the housing 1 is pushed, only the round bar 6 contacts the central cylinder of the annular groove 5.

[0044] The clamp 11 is a ring 1101. The round bar 6 is directly inserted into the ring 1101, aligning the through hole 601 with the bolt 1103 on the fastener 1102. The bolt 1103 is slidably inserted into the through hole 601, and the round bar 6 is locked in place with the nut 1104. The round bar 6 is then fixed to the clamp 11 and will not slide up and down with it. The clamp 11 is rotatably connected to the base 10, allowing the round bar 6 to rotate relative to the base 10.

[0045] The ring-drilling cutter 3 is equipped with a mating key 8, which can drive rotation after mating with the mating groove 602. Therefore, the hollow shaft motor 4 drives the ring-drilling cutter 3 to rotate, which in turn drives the round bar 6 to rotate. However, the ring-drilling cutter 3 will not come into contact with the broken bolt during friction welding.

[0046] Under the action of rotation and thrust, the round bar 6 will rub against the central cylinder of the annular groove 5, generating heat and entering a molten state, causing the round bar 6 and the central cylinder of the annular groove 5 to adhere and form a weld point. During this process, the jamming of the broken bolt in the threaded hole can actually fix the broken bolt in the friction welding, preventing it from rotating with the round bar 6. Furthermore, the rotation direction of the round bar 6 should be the same as the unscrewing direction of the broken bolt to prevent further jamming of the broken bolt under the influence of friction. The annular groove 5 provides heat insulation during friction welding, concentrating heat at the central cylinder of the annular groove 5, thus rapidly heating it to a molten state and preventing the heat generated by friction from melting the threads of the broken bolt and causing it to adhere to the threaded hole. Simultaneously, the annular groove 5 also provides a cavity for weld formation. During friction welding, the molten metal clashes under pressure, and some of the molten metal will bulge outwards, creating a bulging weld scar at the round bar 6 and the central cylinder of the annular groove 5, effectively improving the weld's strength.

[0047] After the friction welding between the round bar 6 and the broken bolt is completed, the clamp 11 releases the round bar 6 and removes the housing 1 from the threaded hole. The round bar 6 will remain on the broken bolt. The user can rotate the round bar 6 in the threaded hole to make the round bar 6 drive the broken bolt to rotate and remove the broken bolt.

[0048] Example 2

[0049] The difference from the above embodiment is that a support platform 16 is welded and fixed to the top of the limiting plate 2, and a second telescopic rod 17 is bolted to the support platform 16. The second telescopic rod 17 is a hydraulic cylinder and is used to drive the housing 1 to slide. An adjustment airbag 18 is provided on the outside of the limiting plate 2. The adjustment airbag 18 is used to expand and adjust the position of the limiting plate 2. An air pump is provided on the support platform 16 for inflating the adjustment airbag 18.

[0050] Both the ring-drilling cutter 3 and the friction welding cutting require downward feed. Especially in friction welding, the greater the downward pressure, the stronger the friction, the greater the heat generated, and the shorter the welding completion time. Therefore, a support platform 16 is provided on the top of the limiting plate 2. The support platform 16 is located outside the threaded hole where the broken screw is located, providing effective support. Furthermore, the second telescopic rod 17 on the support platform 16 can drive the housing 1 to slide, thereby utilizing the force generated by the second telescopic rod 17 for feed, increasing the downward pressure during friction welding.

[0051] Example 3

[0052] The difference from the above embodiment is that the limiting plate 2 is provided with a cooling lubricant release head 19, which is used to spray cooling lubricant onto the thread of the broken bolt. The cooling lubricant release head 19 is a miniature electric nozzle, and the user can supply the cooling lubricant to the cooling lubricant release head 19 through the infusion tube that extends through the limiting plate 2 to the top of the limiting plate 2.

[0053] Friction welding allows for precise control of the welding point. Although the space inside the threaded hole is small, the annular groove 5 significantly isolates heat, reducing the probability of the broken bolt melting and sticking to the threaded hole. To further reduce risk, a cooling lubricant release head 19 can be installed at the bottom of the limiting plate 2. The cooling lubricant release head 19 is small in size and releases a small amount of lubricant. After the annular groove 5 is cut, the cooling lubricant is released to the thread of the broken bolt, allowing the thread of the broken bolt to be cooled by the lubricant, making it less prone to overheating. It also provides lubrication during the subsequent bolt disassembly process, assisting in the disassembly process. At the same time, the recessed design of the annular groove 5 prevents the cooling lubricant from flowing to the top surface of the cylinder, but instead allows it to flow into the bottom of the annular groove 5. Since the heat of friction welding is mainly concentrated on the top surface, it will not interfere with the heating of the friction welding surface, but will instead reduce the heat transfer of friction welding from the cylinder to the broken bolt to the thread.

[0054] Example 4

[0055] The difference from the above embodiment is that it also includes a rod-shaped cutter (not shown in the figure), which is used to cooperate with the mating key 8 to transmit rotation, and is used to grind the central cylinder of the annular groove 5. The bottom of the round rod 6 is rough.

[0056] The cross-section of a broken bolt may be beveled, which reduces the contact area for friction welding and lowers efficiency. Therefore, a bar-shaped cutter can be prepared. This bar-shaped cutter has the same structure as the round bar 6, allowing rotation to be transmitted via the mating key 8 and fixed using the clamp 11. Only the cross-section has a cutting edge, so it directly cuts the top surface of the cylinder during rotation, flattening it. Then, the round bar 6 is replaced for friction welding. The rough bottom of the round bar 6 increases friction, allowing the welding surface to heat up quickly.

[0057] Example 5

[0058] The difference from the above embodiment is that the through hole 601 is detachably connected to the power handle 20.

[0059] The round bar 6 can be inserted into the bolt body 1103 through the through hole 601 for fixation, and can also be inserted into the auxiliary handle 20 for installation. Since the round bar 6 needs to drive the broken bolt to rotate for disassembly, and the rotation torque is related to the rotation diameter, the auxiliary handle 20 can be inserted to increase the rotation diameter and increase the torque.

[0060] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A tooling for removing broken bolts, characterized in that, Includes a housing (1), and a limit plate (2) is slidably connected to the outside of the housing (1); One end of the housing (1) is rotatably connected to a ring-drilling cutter (3), and a hollow shaft motor (4) is fixedly connected to the housing (1). The hollow shaft motor (4) is used to drive the ring-drilling cutter (3) to rotate. The ring-drilling cutter (3) is used to cut an annular groove (5) on the broken bolt under the drive of the hollow shaft motor (4). It also includes a round bar (6), a mating hole (7) is provided in the middle of the ring digging cutter (3), and several mating keys (8) are fixedly connected to the inner side of the mating hole (7). A mating groove (602) is provided on the round bar (6), and the mating key (8) is used to cooperate with the mating groove (602) to transmit rotation. A first telescopic rod (9) is provided on the side of the housing (1) away from the ring digging cutter (3). A seat (10) is fixedly connected to the end of the first telescopic rod (9) away from the housing (1). A clamp (11) is rotatably connected to the seat (10), and the clamp (11) is used to clamp and fix the round bar (6).

2. The tooling for removing broken bolts according to claim 1, characterized in that, The base (10) is connected to a dust suction port (12), and the dust suction port (12) is connected to a vacuum cleaner (13). The vacuum cleaner (13) is used to suck up the metal chips cut by the ring digging tool (3).

3. The tooling for removing broken bolts according to claim 2, characterized in that, The outer side of the base (10) is provided with a fixing ring (14), and the fixing ring (14) is provided with several mounting holes. The locking holes are used to assemble mounting bolts (15).

4. The tooling for removing broken bolts according to claim 3, characterized in that, The clamp (11) includes a ring body (1101), a closed cover is detachably connected to the inner side of the ring body (1101), a fastening frame (1102) is provided on the side of the ring body (1101 away from the ring digging tool (3), a through hole (601) is provided on the round bar (6), a bolt (1103) is slidably connected to the fastening frame (1102), a nut (1104) is detachably connected to the bolt (1103), and the bolt (1103) is used to pass through the through hole (601) to fix the round bar (6).

5. The tooling for removing broken bolts according to claim 4, characterized in that, The top of the limiting plate (2) is fixedly connected to a support platform (16), and a second telescopic rod (17) is fixedly connected to the support platform (16). The second telescopic rod (17) is used to drive the housing (1) to slide.

6. The tooling for removing broken bolts according to claim 5, characterized in that, An adjustment airbag (18) is provided on the outside of the limiting plate (2). The adjustment airbag (18) is used to expand and adjust the position of the limiting plate (2).

7. The tooling for removing broken bolts according to claim 6, characterized in that, The limiting plate (2) is provided with a cooling and lubricating fluid release head (19), which is used to spray the cooling and lubricating fluid onto the thread of the broken bolt.

8. The tooling for removing broken bolts according to claim 7, characterized in that, It also includes a bar-shaped cutter, which is used to cooperate with the mating key (8) to transmit rotation, and the bar-shaped cutter is used to grind the central cylinder of the annular groove (5).

9. The tooling for removing broken bolts according to claim 8, characterized in that, The bottom of the round bar (6) is rough.

10. The tooling for removing broken bolts according to claim 9, characterized in that, The through hole (601) is detachably connected to the power handle (20).

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