Variable pressure feed yielding anchor

Abstract

The utility model belongs to the technical field of anchoring equipment. The utility model discloses a yield pressure anchor rod of variable pressure feed, simple structure, convenient installation, reliable yield pressure, not easy to jam. Adopt the following technical scheme, including the anchor rod body, yield pressure mechanism and preloading mechanism, the free end of anchor rod body is equipped with yield pressure mechanism, and the yield pressure mechanism is equipped with preloading mechanism, in the yield pressure mechanism, the yield pressure cylinder is equipped in the free end of anchor rod body, and the inner wall on the rear end of yield pressure cylinder is provided with the yield pressure taper surface that contracts from the end face to the inside, in the yield pressure nut, the driving section has internal thread, one end of yield pressure section is fixed with the driving section, the other end is fixed with the large diameter end of conical feed section, and a plurality of expansion joints are arranged on the conical feed section, the yield pressure nut is connected with the free end of anchor rod body through the driving section, and the conical feed section of yield pressure nut extrudes into the yield pressure taper surface of the rear end of yield pressure cylinder. The utility model is used for surrounding rock support, simple structure, convenient installation, reliable yield pressure.

Description

Technical Field

[0001] This utility model relates to a variable pressure feed relief anchor bolt, belonging to the technical field of anchoring equipment. Background Technology

[0002] Rock bolts are a fundamental component of roadway support in modern coal mines. They reinforce the surrounding rock of the roadway, allowing the rock to support itself. Rock bolts are not only used in mines but also in engineering projects for the main reinforcement of slopes, tunnels, and dams.

[0003] Ordinary anchor bolts, as tension members extending deep into the ground, are connected to the engineering structure at one end and extend into the ground at the other. The entire anchor bolt is divided into a free section and an anchored section. The free section is the area that transmits the tension at the anchor head to the anchored body, and its function is to apply prestress to the anchor bolt. When the rock strata are not stable enough, the two ends of the anchor bolt will apply axial and multi-directional tension and compression. If the two ends of the anchor bolt are fixed, the forces in all directions may directly break the anchor bolt, causing a risk. However, the constant resistance mechanism of the yielding anchor bolt can release the load on the anchor bolt through large-scale plastic deformation or structural displacement, avoiding the anchor bolt from breaking and better ensuring safety.

[0004] The original design purpose of the sliding anchor bolt was to solve the problem of jamming of the pressure mechanism. However, in actual manufacturing, if there is an error in the conical machining of the pressure ring and the washer, it can easily cause abnormal engagement. This can lead to plowing debris during subsequent sliding, resulting in jamming. In addition, if too much force is applied to the fastening end during installation, it may cause overload jamming.

[0005] For example, the invention patent with application number CN202011555419.5 discloses a bonded anchoring type pre-anchoring pressure relief hollow anchor rod and anchoring method. Although it can automatically extend when the surrounding rock of the tunnel undergoes large deformation and maintain constant working resistance to absorb the energy of the surrounding rock, its structure is relatively complex. It requires the cooperation of an outer sleeve, a pressure relief cylinder and a pressure relief nut to achieve this, and the precision requirements are high. In actual use, the effect is not good. Utility Model Content

[0006] To address the shortcomings of existing technologies, the purpose of this utility model is to provide a variable pressure feed relief anchor bolt with a simple structure, convenient installation, reliable pressure relief, and resistance to jamming.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a variable pressure feed relief anchor bolt, comprising an anchor bolt body, a relief mechanism and a pre-tightening mechanism, wherein the front end of the anchor bolt body is the anchoring end and the rear end is the free end, a relief mechanism is fitted outside the free end of the anchor bolt body, and a pre-tightening mechanism is fitted outside the relief mechanism. The pressure relief mechanism includes a pressure relief nut and a pressure relief cylinder. The pressure relief cylinder is fitted outside the free end of the anchor rod body. There is a gap between the pressure relief cylinder and the anchor rod body. The inner wall of the rear end of the pressure relief cylinder is provided with a pressure relief cone surface that shrinks inward from the end face. The outer circular surface of the rear end of the pressure relief cylinder is provided with a pre-tightening thread. The pressure relief nut includes a drive section, a pressure relief section and a tapered feed section arranged coaxially. The drive section has an internal thread. One end of the pressure relief section is fixed to the drive section and the other end is fixed to the large-diameter end of the tapered feed section. Multiple expansion joints are opened on the tapered feed section to give it radial elasticity. The pressure relief nut is threadedly connected to the free end of the anchor rod body via a drive section, and the tapered feed section of the pressure relief nut is squeezed into the pressure relief cone surface at the rear end of the pressure relief cylinder; the diameter of the small diameter end of the tapered feed section is larger than the diameter of the anchor rod body. The pre-tightening mechanism includes a pad and a fastening nut, which are sequentially fitted onto the outside of the pressure relief cylinder. The fastening nut is connected to the pre-tightening thread at the rear end of the pressure relief cylinder.

[0008] Preferably, the front end of the pressure cylinder extends toward the axial direction to form a shielding part, and a sealing ring is provided between the shielding part and the anchor rod body, and the sealing ring is fixed on the shielding part.

[0009] Preferably, in the pressure relief nut, the outer circular surface of the pressure relief section and the conical surface of the conical feed section have a smooth transition, and there is an expansion step between the inner wall of the pressure relief section and the inner wall of the large-diameter end of the conical feed section. That is, the inner diameter of the large-diameter section of the conical feed section is larger than the inner diameter of the pressure relief section.

[0010] Preferably, the large-diameter end of the pressure cone is also smoothly connected to an inner cylindrical surface, allowing the front end of the pressure section to slide into the inner cylindrical surface.

[0011] Preferably, the middle part of the pad protrudes backward to form a mounting platform and is in contact with the fastening nut, and the edge of the pad transitions to the mounting platform through an inclined surface.

[0012] Preferably, the end face of the fastening nut that contacts the mounting platform is a convex curved surface or a conical surface, and the mounting platform is provided with a matching mounting hole.

[0013] Preferably, the mounting hole is a tapered hole.

[0014] Preferably, the inclined surface has multiple pressure relief holes.

[0015] Compared with the prior art, the present invention has the following beneficial effects.

[0016] 1. In this utility model, by cooperating the tapered feed section in the pressure relief nut and the pressure relief cone surface on the pressure relief cylinder, and by setting an expansion joint on the tapered feed section, the pressure relief process is transformed from traditional rigid sliding friction to controllable elastic sliding friction. This greatly reduces the risk of the mechanism jamming due to processing errors or overload, and ensures that the anchor rod can smoothly relieve pressure when the surrounding rock deforms, continuously providing support resistance, thereby significantly improving the safety and reliability of the support system.

[0017] 2. In this utility model, there is an expansion step between the inner wall of the pressure section and the inner wall of the large-diameter end of the tapered feed section. That is, the inner diameter of the large-diameter end of the tapered feed section is larger than the diameter of the anchor rod body and also larger than the inner diameter of the pressure section. This allows the tapered feed section to shrink more evenly towards the anchor rod body, and its shrinkage deformation can be carried out more freely. This provides space for the axial feeding of the pressure nut, ensures smooth feeding, and maintains the stability of the pressure process.

[0018] 3. In this utility model, the fit between the pressure-relief section of the pressure-relief nut and the inner cylindrical surface of the rear end of the pressure-relief cylinder provides radial support and guidance for the pressure-relief nut, ensuring its smooth movement along the axial direction during the pressure process and preventing skewing or jamming. The smooth transition between the outer cylindrical surface of the pressure-relief section and the conical surface of the conical feed section effectively reduces stress concentration, improves the structural strength and fatigue life of the pressure-relief nut, and makes the entire pressure-relief process more stable and controllable. The shielding part at the front end of the pressure-relief cylinder and the sealing ring together form an effective physical barrier, which can prevent foreign objects such as mud, coal dust, and moisture in the roadway from entering the interior of the pressure-relief cylinder. This protects the precision conical mating surface and expansion joint, avoiding wear, corrosion, and jamming caused by impurities, and greatly improving the long-term working reliability and service life of the pressure-relief mechanism in harsh underground environments.

[0019] 4. In this utility model, the pre-tightening mechanism is fitted outside the pressure-releasing mechanism, making the pre-tightening mechanism external, resulting in a modular structure, clear installation logic, and the pre-tightening mechanism includes: a. The convex curved or conical surface at the front end of the fastening nut and the mounting hole of the pad form an adaptive self-aligning mechanism. This ensures that even if the rock wall surface is uneven or the pad is tilted, the preload can be evenly transmitted to the pad, avoiding pad deformation or preload loss due to uneven force distribution, and ensuring the initial preload effect.

[0020] b. The raised mounting platform structure enhances the rigidity of the center of the pad, enabling it to better withstand and transmit concentrated loads from the fastening nuts; the inclined transition design with the edge can more smoothly distribute the pressure to a larger contact area with the surrounding rock, reduce the pressure of the pad on the rock surface, prevent local crushing of brittle rock surfaces, and improve the stability of the support.

[0021] c. The pressure relief hole on the inclined surface of the pad acts as a built-in safety valve. In extreme cases, if the surrounding rock pressure increases dramatically and the pressure relief mechanism has reached its maximum stroke, the high-pressure debris or gas accumulated under the pad can be released through the pressure relief hole, thereby preventing the pad from being crushed instantly or causing explosive damage, and providing the last safety barrier for the entire support system. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of this utility model.

[0024] Figure 2 This is a cross-sectional structural diagram of the present invention.

[0025] Figure 3 This is a schematic diagram of the structure of the pressure relief nut in this utility model.

[0026] Figure 4 This is a schematic diagram of the pressure cylinder in this utility model.

[0027] Figure 5 This is a schematic diagram of the structure of the pad in this utility model.

[0028] In the diagram: 1 is the anchor bolt body, 11 is the anchoring end, and 12 is the free end; 2 is the pressure relief mechanism, 21 is the pressure relief nut, 211 is the drive section, 212 is the pressure relief section, 213 is the tapered feed section, 214 is the expansion joint, 22 is the pressure relief cylinder, 221 is the pressure relief cone surface, 222 is the pre-tightening thread, 223 is the shielding part, 224 is the sealing ring, and 225 is the inner cylindrical surface. 3 is the pre-tightening mechanism, 31 is the pad, 311 is the mounting platform, 312 is the inclined surface, 313 is the mounting hole, 314 is the pressure relief hole, and 32 is the fastening nut. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described in conjunction with the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0030] It should be noted that the structures, proportions, sizes, etc. shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this utility model can be implemented. Therefore, they have no substantial technical significance. Any modification to the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed in this utility model, provided that it does not affect the effects and purposes that this utility model can produce. It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0031] The present invention provides the following embodiments.

[0032] like Figure 1 , Figure 2 As shown, the present invention provides a variable pressure feed pressure relief anchor bolt, including an anchor bolt body 1, a pressure relief mechanism 2 and a pre-tightening mechanism 3. The front end of the anchor bolt body 1 is the anchoring end 11 and the rear end is the free end 12. The pressure relief mechanism 2 is fitted on the free end 12 of the anchor bolt body 1, and the pre-tightening mechanism 3 is fitted on the pressure relief mechanism 2. The pressure-relief mechanism 2 includes a pressure-relief nut 21 and a pressure-relief cylinder 22. The pressure-relief cylinder 22 is fitted onto the free end 12 of the anchor bolt body 1, with a gap between the pressure-relief cylinder 22 and the anchor bolt body 1. The inner wall of the rear end of the pressure-relief cylinder 22 is provided with a pressure-relief conical surface 221 that tapers inward from the end face, and a pre-tightening thread 222 is provided on the outer circular surface of the rear end of the pressure-relief cylinder 22. Figure 4 As shown; like Figure 2 , Figure 3 As shown, the pressure relief nut 21 includes a drive section 211, a pressure relief section 212 and a tapered feed section 213 arranged coaxially. The drive section 211 has an internal thread. One end of the pressure relief section 212 is fixed to the drive section 211 and the other end is fixed to the large diameter end of the tapered feed section 213. The tapered feed section 213 has multiple expansion joints 214 that give it radial elasticity. The pressure relief nut 21 is threadedly connected to the free end 12 of the anchor rod body 1 through the drive section 211. The tapered feed section 213 of the pressure relief nut 21 is squeezed into the pressure relief cone surface 221 at the rear end of the pressure relief cylinder 22. The diameter of the small diameter end of the tapered feed section 213 is larger than the diameter of the anchor rod body 1. Both the pressure relief nut 21 and the pressure relief cylinder 22 are made of high-strength alloy steel. The driving section 211 of the pressure relief nut 21 is usually machined into a hexagonal head or an internal hexagonal hole, which makes it easy to drive its rotation with tools such as wrenches.

[0033] The pre-tightening mechanism 3 includes a pad 31 and a fastening nut 32. The pad 31 and the fastening nut 32 are sequentially fitted onto the outside of the pressure relief cylinder 22. The fastening nut 32 is connected to the pre-tightening thread 222 at the rear end of the pressure relief cylinder 22.

[0034] The above-mentioned structure of this utility model uses the tapered feed section 213 in the pressure relief nut 21 and the pressure relief cone surface 221 on the pressure relief cylinder 22 to cooperate, and an expansion joint 214 is set on the tapered feed section 213, so that the pressure relief process is changed from the traditional rigid sliding friction to controllable elastic sliding friction. This greatly reduces the risk of the mechanism jamming due to processing errors or overload, and ensures that the anchor rod can smoothly relieve pressure when the surrounding rock deforms, continuously providing support resistance, thereby significantly improving the safety and reliability of the support system.

[0035] like Figure 4 As shown, the front end of the pressure cylinder 22 extends toward the axial direction to form a shielding part 223. A sealing ring 224 is provided between the shielding part 223 and the anchor rod body 1, and the sealing ring 224 is fixed on the shielding part 223.

[0036] The shielding part 223 and the sealing ring 224 together form an effective physical barrier, which can prevent foreign objects such as mud, sand, coal dust, and moisture in the roadway from entering the pressure relief cylinder 22. This protects the precision conical mating surface and expansion joint 214, avoids wear, corrosion and jamming caused by impurities, and greatly improves the long-term working reliability and service life of the pressure relief mechanism 2 in harsh underground environments.

[0037] In the pressure relief nut 21, there is a smooth transition between the outer circular surface of the pressure relief section 212 and the conical surface of the conical feed section 213, and there is an expansion step between the inner wall of the pressure relief section 212 and the inner wall of the large-diameter end of the conical feed section 213. That is, the inner diameter of the large-diameter section of the conical feed section 213 is larger than the inner diameter of the pressure relief section 212.

[0038] The above-mentioned smooth transition design effectively reduces stress concentration, improves the structural strength and fatigue life of the pressure relief nut 21, and makes the entire pressure relief process more stable and controllable.

[0039] The expansion step design makes the inner diameter of the large diameter end of the tapered feed section 213 larger than the diameter of the anchor body 1 and also larger than the inner diameter of the pressure relief section 212. This allows the tapered feed section 213 to contract more evenly towards the anchor body 1, and its contraction deformation can be more free, providing space for the axial feed of the pressure relief nut 21, ensuring smooth feed, and maintaining the stability of the pressure relief process.

[0040] like Figure 4 As shown, the large-diameter end of the pressure cone 221 is also smoothly connected to an inner cylindrical surface 225, allowing the front end of the pressure section 212 to slide into the inner cylindrical surface 225.

[0041] The pressure relief section 212 is cylindrical in shape. Its outer circular surface cooperates with the inner cylindrical surface 225 on the pressure relief cylinder 22 to provide radial support and guidance for the pressure relief nut 21, ensuring that it moves smoothly along the axial direction during the pressure process and preventing deviation or jamming.

[0042] like Figure 5 As shown, the middle part of the pad 31 protrudes backward to form a mounting platform 311 and is attached to the fastening nut 32. The edge of the pad 31 and the mounting platform 311 are connected by an inclined surface 312.

[0043] The raised mounting platform 311 structure in the upper center of the pad 31 enhances the rigidity of the middle part of the pad 31, enabling it to better withstand and transmit the concentrated load from the fastening nut 32; the inclined transition design with the edge can distribute the pressure more smoothly to a larger contact area with the surrounding rock, reduce the pressure of the pad 31 on the rock surface, prevent local crushing of the brittle rock surface, and improve the stability of the support.

[0044] The end face of the fastening nut 32 that contacts the mounting platform 311 is a convex curved surface or a conical surface, and the mounting platform 311 is provided with a matching mounting hole 313.

[0045] The mounting hole 313 is a tapered hole.

[0046] The convex curved surface or conical surface at the front end of the fastening nut 32 and the mounting hole 313 on the pad 31 form an adaptive self-aligning mechanism. This ensures that even if the rock wall surface is uneven or the pad is tilted, the preload can be evenly transmitted to the pad 31, avoiding pad deformation or preload loss due to uneven force distribution, and ensuring the initial preload effect.

[0047] Multiple pressure relief holes 314 are provided on the inclined surface 312.

[0048] The pressure relief hole 314 acts as a built-in safety valve. In extreme cases, if the surrounding rock pressure increases dramatically and the pressure relief mechanism 2 has reached its maximum stroke, the high-pressure debris or gas accumulated under the pad 31 can be released through the pressure relief hole 314, thereby preventing the pad 31 from being crushed instantly or causing explosive damage, and providing the last safety barrier for the entire support system.

[0049] The working process of this utility model is as follows.

[0050] During initial installation and pre-tightening, first, place the pressure relief cylinder 22 onto the free end of the anchor bolt body 1, then tighten the pressure relief nut 21, and insert the tapered feed section 213 of the pressure relief nut 21 between the pressure relief cylinder 22 and the anchor bolt body 1. After assembly, insert it into the drill hole and anchor the anchor end 11. Then, sequentially put on the pad 31 and tighten the nut 32, and use a tool to rotate the drive section 211 of the pressure relief nut 21, causing it to rotate forward on the anchor bolt body 1, i.e., toward the rock wall. As the pressure relief nut 21 rotates, its tapered feed section 213 gradually penetrates and abuts against the pressure relief cone surface 221 of the pressure relief cylinder 22.

[0051] At this point, continue rotating the relief nut 21, and the preload begins to build up. The force transmission path is: relief nut 21 → relief cylinder 22 → fastening nut 32 → pad 31 → rock surface. Simultaneously, the reaction force is transmitted through the anchor rod body 1, causing the entire rod to be under tension, thus completing the preload. During this process, the conical feed section 213 is subjected to axial pressure and conical surface normal force, and its expansion joint 214 has a slight tendency to elastically contract, but macroscopic slippage has not yet occurred.

[0052] Pressure release process: When significant deformation of the surrounding rock occurs, and the tensile force on the anchor bolt body 1 exceeds the preset pressure relief threshold, the enormous axial force will overcome the static friction between the tapered feed section 213 and the pressure relief cone surface 221. Under pressure, the tapered feed section 213 of the pressure relief nut 21 slides inward along the pressure relief cone surface 221 of the pressure relief cylinder 22, i.e., towards the axial direction. This sliding process forces the tapered feed section 213 to undergo radial elastic contraction, narrowing the expansion joint 214.

[0053] This "elastic contraction-sliding" mechanism avoids the "plowing" debris generated by hard scraping between metals, thus fundamentally preventing jamming. The anchor bolt body 1 is then pulled a certain distance, achieving "pressure relief" and releasing the energy of the surrounding rock, while the pressure relief mechanism 2 always maintains a certain working resistance; after the pressure relief ends, this utility model can still maintain a certain support force.

[0054] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A variable pressure feed relief anchor bolt, characterized in that: It includes an anchor body (1), a pressure relief mechanism (2) and a pre-tightening mechanism (3). The front end of the anchor body (1) is the anchoring end (11) and the rear end is the free end (12). The free end (12) of the anchor body (1) is fitted with a pressure relief mechanism (2) and the pressure relief mechanism (2) is fitted with a pre-tightening mechanism (3). The pressure relief mechanism (2) includes a pressure relief nut (21) and a pressure relief cylinder (22). The pressure relief cylinder (22) is fitted outside the free end (12) of the anchor rod body (1). There is a gap between the pressure relief cylinder (22) and the anchor rod body (1). The inner wall of the rear end of the pressure relief cylinder (22) is provided with a pressure relief cone surface (221) that shrinks inward from the end face. The outer circular surface of the rear end of the pressure relief cylinder (22) is provided with a pre-tightening thread (222). The pressure relief nut (21) includes a drive section (211), a pressure relief section (212), and a tapered feed section (213) arranged coaxially. The drive section (211) has an internal thread. One end of the pressure relief section (212) is fixed to the drive section (211), and the other end is fixed to the large-diameter end of the tapered feed section (213). The tapered feed section (213) has multiple expansion joints (214) to give it radial elasticity. The pressure relief nut (21) is threadedly connected to the free end (12) of the anchor body (1) through the drive section (211), and the tapered feed section (213) of the pressure relief nut (21) is squeezed into the pressure relief cone surface (221) at the rear end of the pressure relief cylinder (22); The pre-tightening mechanism (3) includes a pad (31) and a fastening nut (32). The pad (31) and the fastening nut (32) are sequentially fitted onto the outside of the pressure relief cylinder (22). The fastening nut (32) is connected to the pre-tightening thread (222) at the rear end of the pressure relief cylinder (22).

2. The variable pressure feed relief anchor bolt according to claim 1, characterized in that: The front end of the pressure cylinder (22) extends toward the axial direction to form a shielding part (223). A sealing ring (224) is provided between the shielding part (223) and the anchor body (1). The sealing ring (224) is fixed on the shielding part (223).

3. A variable pressure feed relief anchor bolt according to claim 1 or 2, characterized in that: In the pressure relief nut (21), there is a smooth transition between the outer circular surface of the pressure relief section (212) and the conical surface of the conical feed section (213), and there is an expansion step between the inner wall of the pressure relief section (212) and the inner wall of the large diameter end of the conical feed section (213).

4. A variable pressure feed relief anchor bolt according to claim 3, characterized in that: The large-diameter end of the pressure cone (221) is also smoothly connected to an inner cylindrical surface (225), and the front end of the pressure section (212) is slidably fitted into the inner cylindrical surface (225).

5. A variable pressure feed relief anchor bolt according to claim 1 or 2, characterized in that: The middle part of the pad (31) protrudes backward to form a mounting platform (311) and is attached to the fastening nut (32). The edge of the pad (31) and the mounting platform (311) are connected by an inclined surface (312).

6. A variable pressure feed relief anchor bolt according to claim 5, characterized in that: The end face of the fastening nut (32) that contacts the mounting platform (311) is a convex curved surface or a conical surface, and the mounting platform (311) is provided with a matching mounting hole (313).

7. A variable pressure feed relief anchor bolt according to claim 6, characterized in that: The mounting hole (313) is a tapered hole.

8. A variable pressure feed relief anchor bolt according to claim 5, characterized in that: Multiple pressure relief holes (314) are provided on the inclined surface (312).

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