Secondary tensioning and pre-tightening device for coal mine roadway side supporting anchor rod

Abstract

The utility model belongs to the technical field of coal mine roadway supporting, and particularly relates to a secondary tensioning and pre-tightening device for a coal mine roadway side supporting anchor rod, the anchor rod is used for roadway side supporting, an anchor rod tray and an anchor rod nut are arranged on the anchor rod, external threads are arranged on the tail portion of the anchor rod, and the secondary tensioning and pre-tightening device comprises a sleeve, a supporting piece and a hollow jack. The sleeve is in threaded connection with the tail end of the anchor rod, the extension rod is connected outside the sleeve and sequentially penetrates through the supporting piece and the hollow jack, and the limiting nut is arranged at the position, outside the hollow jack, of the extension rod. Compared with the prior art, the device has the advantages that the whole device is simple and reasonable, low in manufacturing cost, convenient to adjust and wide in application range; the hollow jack is small in size, light in weight and convenient to move in a roadway, and the construction efficiency is not affected; tensioning is directly conducted through the hollow jack, the conversion efficiency is high, high pre-tightening force can be provided for the anchor rod, and damage to an anchor rod body and disturbance to surrounding rock are reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal mine roadway support, and particularly relates to a secondary tension pre-tightening device for bolts supporting the sidewall of a coal mine roadway. Background Technique

[0002] Bolt support has become the main support form for coal mine roadways in China. As a carrier for actively supporting surrounding rocks, bolts are bonded to the surrounding rocks through anchoring agents, and then an initial pre-tightening force is applied to the bolts, which can provide a support reaction force for the surrounding rocks of the roadway, improve the stress state of the surrounding rocks, thereby inhibiting and restricting the deformation and displacement of the surrounding rocks. At the same time, the rock mass within the anchoring range of the bolts becomes an organic whole, improving the bonding strength and internal friction angle of the rock mass, so as to achieve the purpose of maintaining the stability of the surrounding rocks.

[0003] The magnitude of the initial pre-tightening force is very important during the construction process of bolt support. A higher pre-tightening force can control the deformation of the surrounding rocks in a timely manner. Generally, the pre-tightening force is about 30% of the yield load of the bolt, usually only 120 - 200 N·m. In actual applications, considering work efficiency and support effect, the sidewall of the roadway needs to be secondarily pre-tightened after bolt support. The main method is to manually use a wrench to apply torque to tighten the bolt nut to achieve re-pre-tightening. However, the pre-tightening force applied by manual secondary pre-tightening has the following problems: 1) In the prior art, the bolt pre-tightening force is mainly obtained by tightening the nut. The friction between the nut and the bolt thread results in low pre-tightening force conversion efficiency; 2) During the pre-tightening process of the nut, the pre-tightening rebound of the bolt causes a large loss of pre-tightening force; 3) After the bolt construction is completed, tightening the nut again requires a large labor intensity for workers; 4) Excessive torque may cause thread damage and disturb the inner anchoring section of the bolt, affecting the bolt anchoring effect.

[0004] A patent document with the patent number CN201620044257.1 discloses an NPR constant-resistance bolt pre-tightening force application device. Those skilled in the art can know from the document that the patent discloses an NPR constant-resistance cable bolt. Its main component, the cable bolt constant resistor, penetrates through the bolt tray. Since the outer diameter of the constant resistor is larger than the outer diameter of the bolt, the size of the bolt tray used is larger than that of a conventional bolt tray. During use, first connect the short cable bolt to the adapter, then tighten the adapter onto the NPR constant-resistance bolt, then let the tensioning tooling pass through the short cable bolt on the adapter, make the tensioning tooling abut against the NPR constant-resistance bolt, and finally let the tensioning machine pass through the short cable bolt, start the hydraulic equipment to make the tensioning machine bite the short cable bolt, and tension the NPR constant-resistance bolt. When the specified pre-tightening force of the bolt is reached, maintain the pre-tightening force, use a pre-tightening wrench to tighten the bolt nut on the bolt through the skylight of the tensioning tooling, and remove the tensioning machine to complete the process of applying the pre-tightening force to the bolt; when a large number of cable bolts / bolts need to be pre-tightened, this device needs to repeatedly disassemble and assemble the tensioning tooling, adapter, and tensioning machine, and the working process is relatively cumbersome, and it is not suitable for the secondary tensioning of bolt support for the sidewall of coal mine roadways. Summary of the Utility Model

[0005] The purpose of the present utility model is to provide a secondary tensioning and preloading device for roadway side support bolts in coal mines, aiming at the problems of cumbersome operation and difficult construction of existing preloading force application devices.

[0006] The present utility model is realized through the following technical solutions: A secondary tensioning and preloading device for roadway side support bolts in coal mines. The bolt is used for roadway side support, and an anchor tray and an anchor nut are arranged on the bolt. The tail of the bolt is provided with an external thread. The secondary tensioning and preloading device includes a sleeve, a support member and a hollow jack. The sleeve is screwed to the end of the bolt, and an extension rod is connected to the outside of the sleeve. The extension rod sequentially passes through the hollow jack and the support member, and a limit nut is arranged at the position of the extension rod outside the hollow jack.

[0007] Specifically, the support member includes a seat body with a through hole. A cylindrical groove is arranged on one side of the seat body close to the sleeve. Threaded holes are evenly distributed around the cylindrical groove, and support rods are screwed into the threaded holes, so that the height of the support rods relative to the seat body is adjustable, and the height of each support rod can be adjusted respectively according to the situation of the support surface to achieve stable support and wide application range.

[0008] Specifically, the top of the support rod is a spherical surface, and four support rods can support on the anchor tray at the same time.

[0009] Specifically, the diameter of the through hole is larger than the diameters of the bolt, the extension rod and the sleeve, ensuring that the diameter of the support rod is 16 - 22 mm, and the distance between the central axes of adjacent two support rods is not greater than 80 mm; the height of the seat body is not less than 80 mm, and the length of the support rod is not less than 120 mm; when the support rod is screwed into the seat body for preloading support, the overall length is 180 - 200 mm.

[0010] Specifically, a threaded hole matching the external thread at the tail of the bolt is arranged on one side of the sleeve, and the depth of the threaded hole is not less than 50 mm to ensure the screwing stability.

[0011] Specifically, the sleeve and the extension rod are detachably fixed or welded and fixed.

[0012] Specifically, the support member, the sleeve and the extension rod are made of steel materials, which can ensure the overall stability during tensioning and preloading.

[0013] Before use, fix the sleeve and the extension rod, and fix the tail of the extension rod with a limit nut after passing through the support member and the hollow jack in sequence; screw and fix the support rod to the seat body so that the overall length of the seat body and the support rod is 180 - 200 mm; at this time, the sleeve, the extension rod, the support member and the hollow jack are combined to form the overall tensioning and preloading device, and the sleeve and the extension rod move relative to the support member and the hollow jack;

[0014] When tension preloading is required, screw the sleeve onto the bolt that needs to be tension preloaded, so that the 4 support rods abut against the bolt tray, and adjust the limit nut to make the hollow jack closely abut against the outside of the support seat body; use the hydraulic cylinder used in conjunction with the hollow jack to make the hollow jack tension the bolt through the extension rod, so that the tensile force of the bolt reaches more than 60%; after completing the tension preloading, maintain the tension, and use a wrench to tighten the bolt nut;

[0015] After completion, relieve the pressure on the hollow jack, and then rotate the sleeve in the reverse direction to make the whole tension preloading device disengage from the bolt, which can be used for the tension preloading of other bolts.

[0016] Due to the connection method between the sleeve and the bolt, there is a certain adjustable space between the whole tension preloading device and the bolt. Generally, there is no need to adjust between the support rod and the seat body, which can ensure the conversion efficiency and simplify the operation process of secondary tension preloading.

[0017] The utility model has the following advantages compared with the prior art: the overall device is simple and reasonable, with low manufacturing cost, convenient to adjust, and wide application range; the hollow jack is small in size and light in weight, convenient to move in the roadway, and used for secondary tensioning will not increase the workload of the staff, and does not change the construction process and does not affect the construction efficiency at the underground construction site;

[0018] By reasonably designing the structure of the support member, it can be adjusted according to the actual situation, which is convenient for the wrench to tighten the bolt nut or the sleeve through the support rod; by cooperating with the sleeve and the extension rod, there is no need to repeatedly disassemble and assemble the hollow jack, which simplifies the working process;

[0019] Direct tensioning is carried out by using the hollow jack, and the conversion efficiency is relatively high, which can provide a relatively high preloading force for the bolt, and timely control the deformation and separation of the surrounding rock; the shear and torsion resistance of the bolt and the surrounding rock are relatively poor, and the application of compressive stress in the form of tensioning reduces the damage to the bolt body and the disturbance to the surrounding rock. Brief Description of the Drawings

[0020] Figure 1 It is a schematic diagram of the use structure of the device of the utility model.

[0021] Figure 2 is Figure 1 The sectional view of.

[0022] Figure 3 It is a schematic diagram of the structure of the support member.

[0023] Figure 4 It is a schematic diagram of the structure of the sleeve and the extension rod.

[0024] Among them, 1 is a hollow jack, 11 is an inner cylinder, 12 is an outer cylinder, 2 is a seat body, 21 is a support rod, 211 is an upper rod, 212 is a lower rod, 22 is a cylindrical groove, 23 is a through hole, 24 is a screwing hole, 3 is a sleeve, 31 is a screwing hole, 4 is an extension rod, 5 is an anchor rod, 6 is an anchor rod nut, 7 is an anchor rod tray, and 8 is a limit nut. Specific embodiments

[0025] The present utility model will be further described below with reference to the accompanying drawings.

[0026] The technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts belong to the scope of protection of the present utility model. Embodiment 1

[0027] As Figures 1-4 shown, a secondary tensioning and preloading device for an anchor rod for supporting the sidewall of a coal mine roadway, the anchor rod 5 is used for supporting the sidewall of the roadway, an anchor rod tray 7 and an anchor rod nut 6 are provided on the anchor rod 5. In this embodiment, the diameter of the anchor rod is 20 mm. The tail of the anchor rod 5 is provided with an external thread, and includes a sleeve 3, a support member and a hollow jack 1. The sleeve 3 is screwed to the end of the anchor rod 5. An extension rod 4 is connected to the outside of the sleeve 3. In this embodiment, the sleeve 3 and the extension rod 4 are of an integral structure. The extension rod 4 sequentially passes through the support member and the hollow jack 1. A limit nut 8 is provided at a position where the extension rod 4 is outside the hollow jack 1. The support member, the sleeve 3 and the extension rod 4 are made of steel materials;

[0028] As Figure 3 shown, the support member includes a seat body 2 with a through hole 23. A cylindrical groove 22 is provided on one side of the seat body 2 close to the sleeve 3. The setting of the cylindrical groove 22 can increase the moving space of the sleeve 3. Screwing holes 24 are evenly distributed around the cylindrical groove 22. A support rod 21 is screwed into the screwing hole 24. The support rod includes an upper rod 211 and a lower rod 212. An external thread matching the internal thread of the screwing hole 24 is provided on the outside of the lower rod 212; the diameter of the through hole 23 is larger than the diameter of the anchor rod 5. The diameter of the support rod 21 is 20 mm. The distance between the central axes of two adjacent support rods is 80 mm; the height of the seat body 2 is 80 mm. The length of the support rod 21 is 90 mm, the length of the upper rod 211 is 50 mm, and the length of the lower rod 212 is 50 mm. The depth of the screwing hole 24 is 60 mm; a screwing hole 31 matching the external thread at the tail of the anchor rod 5 is provided on one side of the sleeve 3. The depth of the screwing hole 31 is 50 mm.

[0029] Before use, the tail of the extension rod 4 is passed through the support member 21 and the hollow jack 1 in sequence and then fixed with the limit nut 8; the support rod 21 is screwed and fixed to the seat body 2, and the overall length of the seat body 2 and the support rod 21 is 200 mm; at this time, the sleeve 3, the extension rod 4, the support member and the hollow jack 1 are combined to form the overall tensioning and preloading device, and the sleeve 3 and the extension rod 4 move relative to the support member and inside the hollow jack;

[0030] When tensioning and preloading are required, the sleeve 3 is screwed to the bolt 5 to be tensioned and preloaded, so that the 4 support rods 21 abut against the bolt tray 7, and the limit nut 8 is adjusted to make the hollow jack 1 closely abut against the outside of the support member seat body 2; by using a hydraulic cylinder used in cooperation with the hollow jack 1, the inner cylinder 11 and the outer cylinder 12 of the hollow jack 1 apply forces in opposite directions, acting on the extension rod 4 to tension the bolt 5, so that the tensile force of the bolt 5 reaches more than 60%; after the tensioning and preloading are completed, the tension is maintained, and the bolt nut 6 is tightened with a wrench;

[0031] After completion, the hollow jack 1 is depressurized, and then the sleeve 3 is rotated in the reverse direction to disengage the overall tensioning and preloading device from the bolt 5, and it can be used for the tensioning and preloading of other bolts.

[0032] Due to the connection method between the sleeve 3 and the bolt 5, there is a certain adjustable space between the overall tensioning and preloading device and the bolt 5. Generally, no adjustment is required between the support rod 21 and the seat body 2, which can ensure the conversion efficiency while simplifying the operation process of secondary tensioning and preloading. Embodiment 2

[0033] A secondary tensioning and preloading device for a bolt for supporting the sidewall of a coal mine roadway. On the basis of Embodiment 1, the sleeve 3 is screwed and fixed to the extension rod 4, the diameter of the support rod 21 is 16 mm, and the distance between the central axes of two adjacent support rods 21 is 80 mm; the height of the seat body 2 is 90 mm, and the length of the support rod 21 is 90 mm; when the support rod 21 is screwed into the seat body 2 for pre-tightening support, the overall length is 190 mm; the depth of the screw hole 31 is 60 mm. Embodiment

[0034] A secondary tensioning and preloading device for a bolt for supporting the sidewall of a coal mine roadway. On the basis of Embodiment 1, the sleeve is welded and fixed to the extension rod, the diameter of the support rod 21 is 22 mm, and the distance between the central axes of two adjacent support rods 21 is 74 mm; the height of the seat body 2 is 80 mm, and the length of the support rod 21 is 95 mm; when the support rod 21 is screwed into the seat body 2 for pre-tightening support, the overall length is 180 mm; the depth of the screw hole 31 is 65 mm. Embodiment 3

[0035] A secondary tension pre-tightening device for a roadway side support bolt in a coal mine. The bolt 5 is used for roadway side support. An anchor bolt tray 7 and an anchor bolt nut 6 are provided on the bolt 5. In this embodiment, the anchor bolt tray 7 is a butterfly gasket, and the corresponding anchor bolt nut 6 is a spherical nut. If the bolt 5 is not perpendicular to the anchor bolt tray 7, the top of the support rod 21 is a spherical surface in this embodiment, and effective support is achieved by screwing the length of the support rod 21 and adjusted according to the inclination angle. The limit nut 8 is adjusted to make the hollow jack 1 tightly press the support member.

[0036] The foregoing has shown and described the basic principles, main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any aspect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced by the present invention. Any reference signs in the claims should not be regarded as limiting the claimed claim.

[0037] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A secondary tensioning and pre-tightening device for coal mine roadway side support anchor rods, the anchor rods are used for roadway side support, the anchor rods are provided with anchor rod trays and anchor rod nuts, and the tail of the anchor rods is provided with external threads, characterized in that: The secondary tensioning pre-tightening device includes a sleeve, a support and a hollow jack. The sleeve is threadedly connected to the end of the anchor rod, and an extension rod is connected to the outside of the sleeve. The extension rod passes through the hollow jack and the support in sequence. A limit nut is set at the position of the extension rod outside the hollow jack.

2. A secondary tensioning and pre-tightening device for supporting anchor bolts in coal mine tunnels as claimed in claim 1, characterized in that: The support member comprises a seat body with a through hole. A columnar groove is arranged on one side of the seat body close to the sleeve. Screw-on holes are evenly distributed around the columnar groove. The support rod is screwed into the screw-on holes.

3. A secondary tensioning and pre-tightening device for supporting anchor bolts in coal mine tunnels as claimed in claim 2, characterized in that: The diameter of the through hole is larger than that of the anchor rod and the extension rod, the diameter of the support rod is 16-22 mm, and the distance between the central axes of two adjacent support rods is not more than 80 mm; the height of the seat body is not less than 80 mm, and the length of the support rod is not less than 120 mm.

4. A secondary tensioning and pre-tightening device for supporting anchor bolts in coal mine tunnels as claimed in claim 2, characterized in that: The top of the support rod is a spherical surface.

5. A secondary tensioning and pre-tightening device for supporting anchor bolts in coal mine tunnels as claimed in claim 1, characterized in that: A screw hole matching the external thread at the tail of the anchor rod is provided on one side of the sleeve, and the depth of the screw hole is not less than 50 mm.

6. A secondary tensioning and pre-tightening device for supporting anchor bolts in coal mine tunnels as claimed in claim 1, characterized in that: The sleeve and the extension rod can be detachably fixed or welded.

7. A secondary tensioning and pre-tightening device for supporting anchor bolts in coal mine tunnels as claimed in claim 1, characterized in that: The support member, sleeve and extension rod are made of steel.

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