Rock bolt connector

Abstract

To provide a connected body of a rock bolt and a construction method therefor that can easily conduct alignment between rock bolts.SOLUTION: The present invention includes a first rock bolt, a cylindrical sleeve that is provided at a rear end of the first rock bolt and where a first female screw is formed, a second rock bolt where a first male screw is formed at a tip end and that is configured so as to screw the first male screw to the first female screw of the sleeve, and an alignment mechanism of conducting alignment between the first female screw and the first male screw of the second rock bolt.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a rock bolt connector. [Background technology]

[0002] In recent years, a method has been proposed for constructing a longer connected body of rock bolts by connecting the next rock bolt to the first rock bolt that has been driven in (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-21216 Summary of the Invention [Problem to be solved by the invention]

[0004] When connecting rock bolts with screws, the second rock bolt must be positioned so that its axis is aligned with the axis of the first rock bolt. This alignment is difficult whether it's mechanical installation, as in Patent Document 1, or manual installation performed by a person climbing to a high location. In particular, rock bolts used as tunnel support are installed radially outward from the tunnel wall, making it extremely difficult to visually align the axis of the second bolt by visually inspecting the rear end of the first bolt installed first, as shown in Figure 12. Furthermore, attempting to thread the male and female threads together when the axes are not aligned can result in damage to the threads.

[0005] The present invention has been made to solve the above problems, and aims to provide a rock bolt connector that allows for easy alignment of the rock bolts, and an installation method thereof. [Means for solving the problem]

[0006] The present invention comprises a first lock bolt, a cylindrical sleeve provided at the rear end of the first lock bolt and having a first female thread formed therein, a second lock bolt having a first male thread formed at its tip end and configured so that the first male thread screws into the first female thread of the sleeve, and a centering mechanism for aligning the first female thread with the first male thread of the second lock bolt.

[0007] In the above-mentioned lock bolt connection body, the centering mechanism can be configured to include a cylindrical protrusion that protrudes axially from the first male thread of the first lock bolt and has an outer diameter smaller than that of the first male thread, and a circular cross-sectional insertion portion that is formed on the inner wall surface of the sleeve closer to the first lock bolt than the first female thread and has an inner diameter approximately the same as the outer diameter of the protrusion, and the axis of the first male thread and the axis of the protrusion are aligned.

[0008] In the above-mentioned lock bolt connection body, the centering mechanism can be configured to include a cylindrical cover member at the tip of the first lock bolt that covers the first male thread so as to form a gap between the first male thread and the cover member, and the inner diameter of the cover member and the outer diameter of the sleeve can be approximately the same, and the axis of the first male thread and the axis of the cover member can be aligned.

[0009] In the above-described lock bolt connection body, the first lock bolt and the sleeve can be integrally formed.

[0010] In the above-mentioned lock bolt connection body, a second male thread is formed at the rear end of the first lock bolt, and a second female thread that threadably engages with the second male thread of the first lock bolt and the first female thread are formed at both axial ends of the sleeve, and the insertion portion can be formed between the first female thread and the second female thread.

[0011] In the above-mentioned lock bolt connection body, a second male thread is formed at the rear end of the first lock bolt, and a second female thread into which the second male thread of the first lock bolt threads and the first female thread can be formed at at least both axial ends of the sleeve.

[0012] The construction method for a first lock bolt connection of the present invention includes the steps of: driving the first lock bolt into the ground with the sleeve attached to the rear end of the first lock bolt; inserting the protruding portion of the second lock bolt into the rear end of the sleeve and advancing the second lock bolt to insert the protruding portion into the insertion portion while threading the first male thread into the second female thread; and driving the connected first lock bolt and second lock bolt into the ground.

[0013] The construction method for the second lock bolt connection of the present invention includes the steps of: driving the first lock bolt into the ground with the sleeve attached to the rear end of the first lock bolt; advancing the second lock bolt while threading the first male thread into the second female thread so that the sleeve is inserted into the cover member of the second lock bolt; and driving the connected first lock bolt and second lock bolt into the ground. [Effects of the Invention]

[0014] According to the present invention, it is possible to easily align the lock bolts with each other. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of a tunnel in which a rock bolt connector according to one embodiment of the present invention is installed. [Figure 2] FIG. 2 is an exploded view of the lock bolt connector according to the first embodiment. [Figure 3] FIG. 1 is a perspective view showing a rock bolt driving device and a supply device. [Figure 4]It is a cross-sectional view for explaining a construction method of a connecting body of rock bolts according to the first embodiment. [Figure 5] It is a view for explaining the alignment of the axes of the rock bolts according to the first embodiment. [Figure 6] It is a view for explaining the alignment of the axes of the rock bolts according to the first embodiment. [Figure 7] It is a view for explaining the alignment of the axes of the rock bolts according to the first embodiment. [Figure 8] It is an exploded view of a connecting body of rock bolts according to the second embodiment. [Figure 9] It is a view for explaining the alignment of the axes of the rock bolts according to the second embodiment. [Figure 10] It is a view for explaining the alignment of the axes of the rock bolts according to the second embodiment. [Figure 11] It is a view for explaining the alignment of the axes of the rock bolts according to the second embodiment. [Figure 12] It is a view for explaining the connection between the rock bolts to be installed in the tunnel.

MODE FOR CARRYING OUT THE INVENTION

[0016] <A. First Embodiment> Hereinafter, a first embodiment of a connecting body of rock bolts according to the present invention will be described with reference to the drawings. Here, as shown in FIG. 1, in the natural ground 20 of the tunnel 10, a connecting body of rock bolts in which the first rock bolt 1 and the second rock bolt 2 are connected via a sleeve 3 is installed in the natural ground 20 of the tunnel 10 so that the rock bolts extend over the entire region where support is required. Hereinafter, for the sake of convenience of explanation, the tip side in the driving direction of each rock bolt will be referred to as the "tip" and the rear end side as the "rear end".

[0017] <1. First Rock Bolt> Figure 2 is a side view of the first lock bolt, sleeve, and second lock bolt. As shown in Figure 2, the first lock bolt 1 has an uneven outer surface. A conical tip member 11 is attached to the tip of the first lock bolt 1. Meanwhile, a male thread (second male thread) 12 is formed at the rear end of the first lock bolt 1.

[0018] <2. Sleeve> 2, the sleeve 3 is formed in a cylindrical shape, and is formed with a front-end female thread (second female thread) 31 and a rear-end female thread (first female thread) 32 at the front and rear ends in the axial direction, respectively. In addition, an insertion portion 33 having a circular cross section and an inner diameter that is approximately the same as or smaller than the threads of each female thread 31, 32 is formed between the two female threads 31, 32 to connect the two female threads 31, 32. The two female threads 31, 32 have the same diameter, and are adapted to be threadedly engaged with the male thread 12 of the first lock bolt 1 and the male thread 21 of the second lock bolt 2, which will be described next.

[0019] <3. Second rock bolt> As shown in Figure 2, the second lock bolt 2 has an uneven outer surface. A male thread (first male thread) 21 is formed at the tip of the second lock bolt 2, and a cylindrical protrusion 23 protrudes from this male thread 21 in the axial direction. The outer diameter of the protrusion 23 is smaller than the root of the male thread 21, and is formed so that the axis of the protrusion 23 coincides with the axis of the male thread 21. A taper 231 is formed on the outer edge of the tip of the protrusion 23. Furthermore, the outer diameter of this protrusion 23 is formed to be approximately the same as or slightly smaller than the inner diameter of the insertion portion 33 of the sleeve 3. Meanwhile, a male thread 22 having the same diameter as the male thread 12 of the first lock bolt 1 is formed at the rear end of the second lock bolt 2.

[0020] <4. Construction method of rock bolt connector> In this embodiment, as shown in Figure 1, a plurality of rock bolts 1, 2 are driven radially from the inner wall surface of the tunnel at predetermined intervals in the circumferential direction, and then further driven at predetermined intervals in the axial direction. One of these bolts will be described below.

[0021] First, the rock bolt driving device and supply device will be described with reference to Figure 3. As shown in Figure 3, the driving device 4 includes a guide cell 41 arranged in the direction of drilling and a drifter (driving machine) 42 that slides on the guide cell 41 and to which rock bolts 1 and 2 are attached. A centralizer 43 is provided at the tip of the guide cell 41, and a subcentralizer 44 is provided behind the centralizer 43. The centralizer 43 has through-holes through which the rock bolts 1 and 2 are inserted, allowing the rock bolts 1 and 2 to be supported straight from the drifter 42. The subcentralizer 44 also serves a similar purpose, but instead of through-holes, it has notches formed in it so that the rock bolts installed in the supply device 5 can be supplied onto the subcentralizer 44. This allows the rock bolts 1 and 2 to be placed onto the notches from the radially outer side of the subcentralizer 44. In this way, the rock bolts 1 and 2 are driven into the ground by the drifter 42 while being supported by the centralizer 43 and the sub-centralizer 44.

[0022] The drifter 42 is a well-known type and is configured to apply rotational force and intermittent impact force to the attached rock bolts 1 and 2, and is moved forward or backward on the guide cell 41 toward drilling by a drive device not shown.

[0023] Next, the lock bolt supply device 5 will be described. As shown in FIG. 3, the lock bolt supply device 5 is provided with multiple rotatable magazines 51 each holding four lock bolts. The four lock bolts are first and second lock bolts 1 and 2. For example, two first lock bolts 1 and two second lock bolts 2 can be installed. Each magazine 51 is formed in a disk shape and is arranged at a predetermined interval in the axial direction. Four recesses 511 are formed on the outer circumferential surface of each magazine 51 at equal intervals in the circumferential direction, and a lock bolt 1 or 2 is housed in each recess 511. Each recess 511 housing the lock bolts 1 and 2 is fitted with an openable lid 512, which prevents the lock bolts 1 and 2 from coming off the recess 511. The number of lock bolts that can be held can be any number other than four.

[0024] To supply the rock bolts 1, 2 from the supply device 5, the magazine 51 is rotated so that one of the recesses 511 containing the rock bolts 1, 2 to be supplied faces the driving device 4. Next, the lid 512 is opened, and the rock bolts 1, 2 are placed on the driving device 4 and connected to the drifter 42. Although not shown, a mechanism is provided on the driving device 4 that supports the supplied rock bolts 1, 2 and automatically connects the rock bolts 1, 2 to the drifter 42.

[0025] Next, a method for installing rock bolts will be described with reference to Figures 4 to 7. First, as shown in Figure 4(a), a hole 6 is bored in the inner wall surface of the tunnel using a known method, and an injection material 61 such as mortar is poured into the bore hole 6. The above-mentioned concrete pouring device 4 is placed outside the bore hole 6, and the sleeve 3 is threaded onto the male thread 12 of the first lock bolt 1, and the female thread 32 on the rear end of the sleeve 3 is attached to a drifter 42.

[0026] Next, as shown in FIG. 4(b), the drifter 42 is advanced and the first lock bolt 1 is inserted into the drilled hole 6. Then, when most of the first lock bolt 1 has been inserted into the drilled hole 6, the connection between the first lock bolt 1 and the drifter 42 is released and the drifter 42 is retracted, as shown in FIG. 4(c). At this time, the sleeve 3 is positioned outside the drilled hole 6. The drifter 42 is also retracted to an extent that the second lock bolt 2 can be placed between the drilled hole 6 and the drifter 42.

[0027] Next, the second lock bolt 2 is supplied from the supply device 5 to the driving device 4, and the male thread 22 of the second lock bolt 2 is attached to the drifter 42. Subsequently, as shown in Figure 4(d), while rotating the second lock bolt 2, the drifter 42 is advanced so that the tip of the second lock bolt 2 faces the rear end of the sleeve 3. As a result, as shown in Figure 4(e), the male thread 21 of the second lock bolt 2 threads into the female thread 32 on the rear end side of the sleeve 3, and the first lock bolt 1 and the second lock bolt 2 are connected via the sleeve 3.

[0028] This point will be explained in detail with reference to Figures 5 to 7. As shown in Figure 5, when the second lock bolt 2 is brought close to the sleeve 3, the male thread 21 of the second lock bolt 2 and the female thread 32 on the rear end of the sleeve 3 may not be aligned. In contrast, in this embodiment, as shown in Figure 6, the protruding portion 23 is configured to enter the sleeve 3 before the male thread 21. As shown in Figure 7, when the second lock bolt 2 is further advanced, the protruding portion 23 enters the insertion portion 33 of the sleeve 3. Because the inner diameter of the insertion portion 33 and the outer diameter of the protruding portion 23 are roughly the same, the protruding portion 23 entering the insertion portion 33 of the sleeve 3 aligns the axes of the sleeve 3 and the second lock bolt 2. Therefore, when the second lock bolt 2 is further advanced and rotated around its axis, the male thread 21 of the second lock bolt 2 and the female thread 32 on the rear end of the sleeve 3 are threadedly engaged with each other while being aligned.

[0029] Next, the drifter 42 is advanced while striking the second rock bolt 2 as necessary. This causes the connected first rock bolt 1 and second rock bolt 2 to be further inserted into the drilled hole 6. In this way, as shown in Figure 4(f), the drifter 42 approaches the drilled hole 6 and the majority of the second rock bolt 2 is inserted into the drilled hole 6, completing the driving of the rock bolts.

[0030] 1, a plurality of rock bolts are driven into the tunnel ground 20 so as to extend radially in the diameter direction. As a result, rock bolts 1 and 2 are driven throughout the entire area where support is required. After that, when the grouting material 61 hardens, the driven rock bolts 1 and 2 are fixed in the ground, reinforcing the ground.

[0031] <5. Features> As described above, according to this embodiment, the second lock bolt 2 has a cylindrical protrusion 23 protruding from the male thread 21, and the sleeve 3 has an insertion section 33 formed on the tip side of the rear-end female thread 32, allowing the protrusion 23 to slide. Therefore, the protrusion 23 enters the insertion section 33 of the sleeve 3 before the male thread 21, thereby aligning the centers of the sleeve 3 and the second lock bolt 2. Therefore, when driving the second lock bolt 2 into a structure such as a tunnel where the axial center of the already-driven first rock bolt 1 is difficult to determine, proper centering can be achieved whether the concrete is driven mechanically or manually. As a result, damage to the threads can be suppressed.

[0032] <6. Variations> Although the first embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications are possible without departing from the spirit of the present invention. The following modifications can be combined as appropriate.

[0033] (1) In the above embodiment, the case where the first lock bolt 1 and the second lock bolt 2 are connected via the sleeve 3 has been described. However, a third lock bolt can also be connected to the rear end of the second lock bolt 2. In this case, with the sleeve 3 attached to the rear end of the second lock bolt 2, a third lock bolt having the same configuration as the second lock bolt 2 is fixed to this sleeve. Therefore, in this configuration, the second lock bolt 2 corresponds to the first lock bolt of the present invention, and the third lock bolt corresponds to the second lock bolt of the present invention.

[0034] That is, as long as it connects the lock bolt on the front end side provided with the above-described sleeve 3 and the lock bolt on the rear end side fixed to this sleeve 3, the number of lock bolts to be connected is not particularly limited. Therefore, as long as a lock bolt having the same configuration as the first lock bolt and the second lock bolt of the present invention is included in the connected body of lock bolts.

[0035] (2) In the above embodiment, the sleeve 3 is screwed onto the first lock bolt 1. However, the first lock bolt 1 and the sleeve 3 can also be integrally formed. That is, without forming the male thread 12 on the first lock bolt 1, a cylindrical portion formed with the insertion portion 33 and the female thread 32 on the rear end side can be integrally provided at the rear end of the first lock bolt 1.

[0036] (3) The structure of the outer peripheral surface of each lock bolt 1 is not particularly limited. In addition to forming a rectangular concave portion as described above, it can also be formed in a screw shape. This is the same in the second embodiment described later.

[0037] (4) In this embodiment, an example where the connected body of lock bolts is driven into the rock mass of the tunnel has been described. However, it is not limited to this, and the present invention can be applied generally to the case of driving lock bolts into rock masses other than tunnels. This is the same in the second embodiment described later.

[0038] <B. Second Embodiment> Next, a second embodiment of a rock bolt connector according to the present invention will be described with reference to the drawings. Like the first embodiment, the rock bolt connector of the second embodiment also comprises a first rock bolt 1 and a second rock bolt 2 connected via a sleeve 3, and is configured to be driven into the natural ground 20 of a tunnel 10. Below, differences from the first embodiment will be mainly described.

[0039] <1. First rock bolt> 8 is a side view of the first lock bolt, sleeve, and second lock bolt. As shown in FIG. 2, the first lock bolt 1 is the same as the first lock bolt 110, and therefore a description thereof will be omitted.

[0040] <2. Sleeve> 8, the sleeve 3 is formed in a cylindrical shape, and a female thread (first female thread) 35 is formed along the entire inner wall surface. The male thread 12 of the first lock bolt 1 and the male thread 21 of the second lock bolt 2, which will be described next, are adapted to be threadedly engaged with this female thread 35.

[0041] <3. Second rock bolt> As shown in Figure 8, the second lock bolt 2 has an uneven outer surface. Furthermore, male threads 21, 22 are formed at the front and rear ends of the second lock bolt 2, respectively. A cylindrical cover member 7 is attached to the front end of the second lock bolt 2 so as to cover the male thread (first male thread) 21. The rear end of this cover member 7 is fixed near the rear end of the male thread 21, and a gap is formed between the inner wall surface of the cover member 7 and the male thread 21. More specifically, the inner diameter of the cover member 7 is formed to be approximately the same as or slightly larger than the outer diameter of the sleeve 3. Furthermore, the axis of the inner wall surface of the cover member 7 and the axis of the male thread 21 are configured to coincide.

[0042] <4. Construction method of rock bolt connector> Next, the method of installing the lock bolt will be described with reference to Figures 9 to 11. The method of installing the lock bolt in the second embodiment is generally the same as that in the first embodiment, but the method of re-aligning the sleeve and the second lock bolt is different, and this point will be described.

[0043] As shown in Figure 9, when the second lock bolt 2 is brought close to the sleeve 3, the male thread 21 of the second lock bolt 2 and the female thread 32 at the rear end of the sleeve 3 may not be aligned. In contrast, in this embodiment, as shown in Figure 10, the cover member 7 is configured to contact the outer peripheral surface of the sleeve 3 before the male thread 21. As shown in Figure 11, when the second lock bolt 2 is further advanced, the sleeve 3 relatively enters the interior of the cover member 7. Because the inner diameter of the cover member 7 and the outer diameter of the sleeve are roughly the same, the sleeve 3 enters the cover member 7, aligning the axes of the sleeve 3 and the second lock bolt 2. Therefore, when the second lock bolt 2 is further advanced and rotated around the axis, the male thread 21 of the second lock bolt 2 and the female thread 35 of the sleeve 3 are threadedly engaged with each other while being aligned.

[0044] <5. Features> As described above, according to this embodiment, a cover member 7 is provided to cover the male thread 21 of the second lock bolt 2. This cover member 7 is configured to be slidable along the outer peripheral surface of the sleeve 3. Therefore, prior to the male thread 21, the cover member 7 slides along the outer peripheral surface of the sleeve 3, thereby aligning the centers of the sleeve 3 and the second lock bolt 2. Therefore, similar to the first embodiment, proper alignment can be achieved whether concrete is poured mechanically or manually. As a result, damage to the threads can be suppressed.

[0045] <6. Variations> Although the second embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. The following modifications can be combined as appropriate.

[0046] (1) In the second embodiment described above, the first lock bolt 1 and the second lock bolt 2 are connected via the sleeve 3, but a third lock bolt can also be connected to the rear end of the second lock bolt 2. In this case, the sleeve 3 is attached to the rear end of the second lock bolt 2, and a third lock bolt having the same configuration as the second lock bolt 2 is fixed to this sleeve. Therefore, in this configuration, the second lock bolt 2 corresponds to the first lock bolt of the present invention, and the third lock bolt corresponds to the second lock bolt of the present invention.

[0047] That is, there is no particular limit to the number of lock bolts to be connected, as long as it connects a lock bolt at the front end provided with the above-mentioned sleeve 3 and a lock bolt at the rear end provided with a cover member fixed to this sleeve 3. Therefore, it is sufficient that the connected body of lock bolts includes lock bolts having the same configuration as the first lock bolt and second lock bolt of the present invention.

[0048] (2) In the above embodiment, the sleeve 3 is threaded onto the first lock bolt 1, but the first lock bolt 1 and the sleeve 3 can also be formed integrally. That is, the first lock bolt 1 does not have a male thread 12, and a cylindrical portion with a female thread 35 can be provided integrally at the rear end of the first lock bolt 1. [Explanation of symbols]

[0049] 1. First rock bolt 12 Male thread 2 Second rock bolt 21 Male thread 23 Protrusion 3 Sleeve 31 Tip female thread 32 Rear end female thread 33 Insertion section 35 female thread 7 Cover member

Claims

1. A first rock bolt; a cylindrical sleeve provided at a rear end of the first lock bolt and having a first female thread formed therein; a second lock bolt having a first male thread formed at a tip portion thereof and configured so that the first male thread is threadably engaged with the first female thread of the sleeve; a centering mechanism for aligning the first female thread with the first male thread of the second lock bolt; Equipped with The centering mechanism includes: a cylindrical cover member provided at a tip portion of the second lock bolt to cover the first male thread so as to form a gap between the first male thread and the cylindrical cover member; The inner diameter of the cover member and the outer diameter of the sleeve are substantially the same, A lock bolt connecting body configured so that the axis of the first male screw and the axis of the cover member coincide with each other.

2. The lockbolt connection assembly according to claim 1 , wherein the first lockbolt and the sleeve are integrally formed.

3. A second male thread is formed at the rear end of the first lock bolt, 2. A lock bolt connection as described in claim 1, wherein at least both axial ends of the sleeve are formed with a second female thread into which the second male thread of the first lock bolt threads and the first female thread.

4. A method for installing the rock bolt connector according to claim 1, a step of driving the first rock bolt into the ground with the sleeve attached to the rear end of the first rock bolt; Threading the first male thread into the first female thread while advancing the second lock bolt so that the sleeve is inserted into a cover member of the second lock bolt; driving the coupled first rock bolt and the second rock bolt into the natural ground; A method for constructing a rock bolt connector, comprising:

Images