Anti-corrosion and anti-loosening anchor rod tail protection sleeve

Abstract

The application discloses an anti-corrosion and anti-loosening protection sleeve for an anchor rod tail, wherein the interior of a sleeve body is provided with a stepped accommodating cavity in the length direction; the stepped accommodating cavity comprises a nut accommodating cavity and a rod body accommodating cavity which are coaxially arranged; the first end of the nut accommodating cavity extends to the first end surface of the sleeve body, and the first end and the middle section of the nut accommodating cavity are respectively provided with a sealing lip and a sealing rib which are annularly protruded towards the center; the inner diameter of the rod body accommodating cavity is smaller than that of the nut accommodating cavity, the length of the rod body accommodating cavity is greater than that of the nut accommodating cavity, the first end of the rod body accommodating cavity is communicated with the last end of the nut accommodating cavity, and the last end of the rod body accommodating cavity extends to a position close to the last end of the sleeve body; the rod body accommodating cavity comprises a threaded locking section close to one side of the nut accommodating cavity and a leading-in section away from the other side; the inner surface of the threaded locking section is provided with an inner thread structure matched with the thread of the anchor rod tail; the cross section of the leading-in section is in the shape of a truncated cone, and the large-diameter end of the leading-in section is communicated with the threaded locking section. The protection sleeve has the effects of excellent anti-corrosion and anti-loosening of the nut.

Description

Technical Field

[0001] This utility model belongs to the technical field of mine support equipment, specifically relating to a corrosion-resistant and anti-loosening anchor bolt tail protective sleeve. Background Technology

[0002] Rock bolt support is one of the most important support methods in underground mine roadways and chambers. The tail of a rock bolt typically consists of a threaded section, a nut, and a washer. Tightening the nut provides preload, enabling the support system to function. However, the underground environment is extremely harsh, characterized by high humidity, corrosive gases (such as H2S and SO2), water spray, and continuous vibrations from blasting and equipment operation. These factors collectively lead to two major problems with the tail of the rock bolt: 1. Corrosion: The threaded parts are highly susceptible to corrosion under corrosive media, causing the nut to stick to the bolt body. This makes it impossible to disassemble when adjusting or retrieving the bolt, and may even render the entire bolt unusable, increasing maintenance costs and construction risks. 2. Loosening: Long-term, severe vibrations underground can easily cause the nut to loosen, resulting in the loss of the rock bolt's preload, significantly reducing the support effect and posing a considerable safety hazard.

[0003] Currently, the commonly used method for protecting the tail of anchor bolts on-site is to apply grease or anti-rust paint to the outside of the threaded joint. However, this method has a short effective period, and the coating is easily washed away by water or contaminated by dust, resulting in poor protective effect and requiring frequent maintenance. Although there are other protective cover products, their structures often have problems such as poor sealing, easy detachment, lack of anti-loosening function, or complex installation, making it difficult to effectively promote them in practice.

[0004] Therefore, there is an urgent need to provide a special protective sleeve for the tail of the anchor bolt that integrates active sealing, long-term corrosion protection and vibration-induced loosening, and has a simple structure and quick installation, so as to solve the problem of long-term protection of the tail of the anchor bolt. Summary of the Invention

[0005] To address the problems existing in the prior art, this utility model provides a corrosion-resistant and anti-loosening protective sleeve for the tail of an anchor bolt. This protective sleeve integrates active sealing, long-term corrosion protection, and vibration-resistant loosening. It has a simple structure and is quick to install. While having excellent corrosion protection, it also prevents the nut from loosening, which helps to ensure the long-term stable support effect of the anchor bolt.

[0006] To achieve the above objectives, this utility model provides a corrosion-resistant and anti-loosening anchor bolt tail protective sleeve, including a sleeve body;

[0007] The sheath body has a stepped receiving cavity along its length; the stepped receiving cavity includes a nut receiving cavity and a rod receiving cavity arranged coaxially.

[0008] The first end of the nut receiving cavity extends to the first end face of the sheath body, and the first end and the middle section of the nut receiving cavity are respectively provided with a sealing lip and a sealing rib that protrude annularly towards the center.

[0009] The inner diameter of the rod receiving cavity is smaller than that of the nut receiving cavity, and its length is greater than that of the nut receiving cavity. Its first end is connected to the end of the nut receiving cavity, and its end extends close to the end of the sheath body. The rod receiving cavity includes a threaded locking section on the side close to the nut receiving cavity and an inlet section on the side away from the nut receiving cavity. The cross-section of the threaded locking section is cylindrical, and its inner surface is provided with an internal thread structure that matches the thread at the tail of the anchor rod. The cross-section of the inlet section is frustoconical, and its large-diameter end is connected to the threaded locking section.

[0010] Furthermore, in order to save materials and to make the overall weight of the protective sleeve lighter, the outer contour of the protective sleeve body is stepped, which includes a nut sleeve section and a screw sleeve section. The nut receiving cavity is located inside the nut sleeve section, and the screw receiving cavity is located inside the screw sleeve section.

[0011] Furthermore, to ensure centered assembly during installation, the inner surface of the inlet section is provided with spiral guide ribs.

[0012] Furthermore, to facilitate assembly and to facilitate the application of a larger preload, the outer surface of the sheath body is provided with anti-slip texture.

[0013] Furthermore, in order to improve the sealing effect and the tightness of the connection, an embedded ring made of elastic material is embedded at the root of the internal thread structure; the cross-section of the embedded ring is circular or elliptical.

[0014] Furthermore, to ensure service life, the sheath body is made of engineering plastic or synthetic rubber in one piece.

[0015] Furthermore, to ensure service life, the synthetic rubber is chloroprene rubber or nitrile rubber.

[0016] In this invention, the stepped receiving cavity of the sheath body includes a nut receiving cavity and a rod receiving cavity. After being installed at the tail of the anchor rod, the nut receiving cavity accommodates the nut and washer on the anchor rod, while the rod receiving cavity accommodates the end of the rod. Sealing lips and sealing ribs are respectively provided in the first and middle sections of the nut receiving cavity, forming a double sealing structure that significantly improves the sealing effect. This effectively prevents most of the humid air, hydrogen sulfide gas, and water from entering the tail space of the anchor rod and the space where the nut is located, thus avoiding corrosion of the external thread section of the anchor rod, the nut, and the washer. For the rod receiving cavity, the section near the nut receiving cavity is a threaded locking section with an internal thread structure. This internal thread structure can mesh with the external thread structure at the tail of the anchor rod, further improving the sealing effect. Simultaneously, this meshing engagement achieves an anti-loosening connection effect. The cross-section of the guide section is frustoconical, forming a guide cone, which facilitates centered assembly during installation. Meanwhile, the tapered inlet will generate continuous radial pressure on the end of the rod due to elastic deformation after installation. In addition, the sealing lip and sealing rib will also generate continuous radial pressure on the nut due to elastic deformation after installation. Since the radial pressure acts on the external thread section of the nut and anchor rod, it can effectively offset the preload loss under vibration conditions, which helps to prevent the nut from loosening.

[0017] Existing protective structures directly target the anchor bolt itself for corrosion protection. While this can isolate corrosive media to some extent, it cannot address the issue of nut loosening caused by downhole vibration. This invention organically combines corrosion protection and anti-loosening functions. Utilizing the sheath body and multiple internal seals, it effectively isolates moisture, corrosive gases, and water, preventing thread and nut corrosion. Simultaneously, its elastic structure provides continuous radial pressure, effectively preventing nut loosening. This comprehensively improves the protection of the anchor bolt tail while also ensuring the anchor bolt's support effectiveness.

[0018] This protective sleeve integrates active sealing, long-term corrosion protection, and vibration-induced loosening prevention. It has a simple structure and is quick to install. While providing excellent corrosion protection, it also prevents the nuts from loosening, which helps ensure the long-term stable support effect of the anchor bolts. It can significantly reduce the maintenance cost of downhole anchor bolt support and improve the safety of the support. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model. Figure 1 ;

[0020] Figure 2 This is a schematic diagram of the structure of this utility model. Figure 2 ;

[0021] Figure 3This is a schematic diagram of the assembly of the utility model and the anchor rod.

[0022] In the diagram: 1. Sheath body, 2. Nut receiving cavity, 3. Rod receiving cavity, 4. Sealing rib, 5. Threaded locking section, 6. Inlet section, 7. Sealing lip, 8. Nut sleeve section, 9. Screw sleeve section, 10. Internal thread structure, 11. Guide rib, 12. Anchor rod, 13. Nut, 14. Top plate. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] like Figures 1 to 3 As shown, the present invention provides a corrosion-resistant and anti-loosening anchor bolt tail protective sleeve, including a sleeve body 1;

[0025] The sheath body 1 has a stepped receiving cavity inside along its length; the stepped receiving cavity includes a nut receiving cavity 2 and a rod receiving cavity 3 arranged coaxially.

[0026] The first end of the nut receiving cavity 2 extends to the first end face of the sheath body 1, and the first end and middle section of the nut receiving cavity 2 are respectively provided with a sealing lip 7 and a sealing rib 4 that protrude annularly towards the center.

[0027] The inner diameter of the rod receiving cavity 3 is smaller than the inner diameter of the nut receiving cavity 2, and its length is greater than the length of the nut receiving cavity 2. Its first end is connected to the end of the nut receiving cavity 2, and its end extends close to the end of the sheath body 1. The rod receiving cavity 3 includes a threaded locking section 5 on the side close to the nut receiving cavity 2 and an inlet section 6 on the side away from the nut receiving cavity 2. The cross-section of the threaded locking section 5 is cylindrical, and its inner surface is provided with an internal thread structure 10 that matches the thread at the tail of the anchor rod 12. The cross-section of the inlet section 6 is frustoconical, and its large-diameter end is connected to the threaded locking section 5.

[0028] To save materials and to make the overall weight of the protective sleeve lighter, the outer contour of the protective sleeve body 1 is stepped, which includes a nut sleeve section 8 and a screw sleeve section 9. The nut receiving cavity 2 is located inside the nut sleeve section 8, and the screw receiving cavity 3 is located inside the screw sleeve section 9.

[0029] To ensure centered assembly during installation, the inner surface of the inlet section 6 is provided with spiral guide ribs 11.

[0030] To facilitate assembly, the outer surface of the sheath body 1 is provided with anti-slip texture.

[0031] To improve sealing and connection tightness, an embedded ring made of elastic material is provided at the root of the internal thread structure 10; the cross-section of the embedded ring is circular or elliptical. In its natural state, the inner diameter of the embedded ring is smaller than the crest diameter of the anchor bolt external thread structure.

[0032] To ensure service life, the sheath body 1 is made of engineering plastic or synthetic rubber in one piece.

[0033] To ensure service life, the synthetic rubber is either chloroprene rubber or nitrile rubber. Nitrile rubber, in particular, has a service life of 1.5-2 years, effectively reducing maintenance costs.

[0034] During use, following the standard downhole anchor bolt 12 support procedure, insert the anchor bolt 12 into the pre-drilled hole in the surrounding rock, and tighten the nut 13 with a torque wrench to achieve the designed preload force. At this point, the nut 13 and the washer are tightly fitted, and the washer is in contact with the surface of the surrounding rock. The operator holds the sheath body 1 and aligns the open end of the nut receiving cavity 2 with the tail of the anchor bolt 12 (the side of the nut 13 away from the washer). By rotating the sheath body 1 clockwise, the internal thread structure 10 on the inner wall gradually engages with the external thread structure of the anchor bolt. During the rotation, the guide rib 11 slides along the external thread section to prevent the sheath body 1 from shifting. Continue rotating the sheath body 1 until the closed end of the sheath body 1 is in close contact with the side of the nut 13 away from the washer. At this point, the sheath body 1 completely covers the external thread section of the anchor bolt 12, the nut 13, and the washer, and the head end of the sheath body 1 abuts against the top plate 14. The installation process is now complete.

[0035] In this invention, the stepped receiving cavity of the sheath body includes a nut receiving cavity and a rod receiving cavity. After being installed at the tail of the anchor rod, the nut receiving cavity accommodates the nut and washer on the anchor rod, while the rod receiving cavity accommodates the end of the rod. Sealing lips and sealing ribs are respectively provided in the first and middle sections of the nut receiving cavity, forming a double sealing structure that significantly improves the sealing effect. This effectively prevents most of the humid air, hydrogen sulfide gas, and water from entering the tail space of the anchor rod and the space where the nut is located, thus avoiding corrosion of the external thread section of the anchor rod, the nut, and the washer. For the rod receiving cavity, the section near the nut receiving cavity is a threaded locking section with an internal thread structure. This internal thread structure can mesh with the external thread structure at the tail of the anchor rod, further improving the sealing effect. Simultaneously, this meshing engagement achieves an anti-loosening connection effect. The cross-section of the guide section is frustoconical, forming a guide cone, which facilitates centered assembly during installation. Meanwhile, the tapered inlet will generate continuous radial pressure on the end of the rod due to elastic deformation after installation. In addition, the sealing lip and sealing rib will also generate continuous radial pressure on the nut due to elastic deformation after installation. Since the radial pressure acts on the external thread section of the nut and anchor rod, it can effectively offset the preload loss under vibration conditions, which helps to prevent the nut from loosening.

[0036] Existing protective structures directly target the anchor bolt itself for corrosion protection. While this can isolate corrosive media to some extent, it cannot address the issue of nut loosening caused by downhole vibration. This invention organically combines corrosion protection and anti-loosening functions. Utilizing the sheath body and multiple internal seals, it effectively isolates moisture, corrosive gases, and water, preventing thread and nut corrosion. Simultaneously, its elastic structure provides continuous radial pressure, effectively preventing nut loosening. This comprehensively improves the protection of the anchor bolt tail while also ensuring the anchor bolt's support effectiveness.

[0037] This protective sleeve integrates active sealing, long-term corrosion protection, and vibration-induced loosening prevention. It has a simple structure and is quick to install. While providing excellent corrosion protection, it also prevents the nuts from loosening, which helps ensure the long-term stable support effect of the anchor bolts. It can significantly reduce the maintenance cost of downhole anchor bolt support and improve the safety of the support.

Claims

1. A corrosion-resistant and anti-loosening anchor bolt tail protective sleeve, comprising a sleeve body (1), characterized in that... ； The sheath body (1) has a stepped receiving cavity inside along its length; the stepped receiving cavity includes a nut receiving cavity (2) and a rod receiving cavity (3) arranged coaxially; The first end of the nut receiving cavity (2) extends to the first end face of the sheath body (1), and the first end and middle section of the nut receiving cavity (2) are respectively provided with a sealing lip (7) and a sealing rib (4) that protrude annularly towards the center. The inner diameter of the rod receiving cavity (3) is smaller than that of the nut receiving cavity (2), and its length is greater than that of the nut receiving cavity (2). Its first end is connected to the end of the nut receiving cavity (2), and its end extends close to the end of the sheath body (1). The rod receiving cavity (3) includes a threaded locking section (5) on the side close to the nut receiving cavity (2) and an inlet section (6) on the side away from the nut receiving cavity (2). The threaded locking section (5) has a cylindrical cross-section, and its inner surface is provided with an internal thread structure (10) that matches the thread at the tail of the anchor rod (12). The inlet section (6) has a frustum-shaped cross-section, and its large diameter end is connected to the threaded locking section (5).

2. The anti-corrosion and anti-loosening anchor bolt tail protective sleeve according to claim 1, characterized in that, The outer contour of the sheath body (1) is stepped, and it includes a nut sleeve section (8) and a screw sleeve section (9). The nut receiving cavity (2) is located inside the nut sleeve section (8), and the rod receiving cavity (3) is located inside the screw sleeve section (9).

3. The anti-corrosion and anti-loosening anchor bolt tail protective sleeve according to claim 1, characterized in that, The inner surface of the inlet section (6) is provided with a spiral guide rib (11).

4. The anti-corrosion and anti-loosening anchor bolt tail protective sleeve according to claim 1, characterized in that, The outer surface of the sheath body (1) is provided with anti-slip texture.

5. The anti-corrosion and anti-loosening anchor bolt tail protective sleeve according to claim 1, characterized in that, The internal thread structure (10) has an embedded ring made of elastic material at the root of the thread; the embedded ring has a circular or elliptical cross section.

6. The anti-corrosion and anti-loosening anchor bolt tail protective sleeve according to claim 1, characterized in that, The sheath body (1) is made of engineering plastic or synthetic rubber in one piece.

7. The anti-corrosion and anti-loosening anchor bolt tail protective sleeve according to claim 6, characterized in that, The synthetic rubber is chloroprene rubber or nitrile rubber.

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