Mortar injection joint structure

Abstract

To easily and surely detach a joint member from an injection hose after injecting mortar, and to surely reuse the joint member for another mortar injection work.SOLUTION: Provided is a mortar injection joint structure that includes: a female arm lock coupling 1 having a substantially cylindrical base part 11, a mounting cylinder part 13, a lever 15 tiltably pivoted on the base part 11, and a cam-like engaging part 16 integrally provided at the root of the lever 15; and a male arm lock coupling 2 having a base cylinder 21, a holding hole 22, and an engaging recess 24. In a base part 11 of the female arm lock coupling 1 in which a force-feed hose 103 is press-fitted and inserted into a mounting cylinder part 13, a base cylinder 21 in which an injection hose 104 of mortar M is held in frictional contact with a holding hole 22 is inserted, the engaging part 16 is releasably engaged with an engaging recessed part 24 to be fixed, and a part of the injection hose 104 is arranged inside a force feed hose 103.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a mortar injection joint structure for connecting a pressure hose of a mortar pressure pump to an injection hose for injecting mortar into a borehole in natural ground, etc. [Background technology]

[0002] Conventionally, when driving a rock bolt into a borehole 101 in natural ground 100 in a tunnel space T as shown in Fig. 8, mortar is injected around the rock bolt in the borehole 101 and, in the case of a post-injection type rock bolt, into a packer provided in the borehole 101 around the mouth of the borehole 101. When injecting mortar, a pressure delivery hose 103 of a mortar pressure delivery pump 102 that mixes and pressure-feeds the mortar and an injection hose 104 that injects the mortar into the borehole 101 are connected by a joint mechanism 200 shown in Figs. 9 and 10.

[0003] This joint mechanism 200 is composed of a plug-in joint 210, a male arm lock coupling 220 of the arm detachable joint, and a female arm lock coupling 230 of the arm detachable joint. In the plug-in joint 210, a seal ring 212 and a leaf spring-like lock claw 213 are provided inside a guide tube portion 211, and a part of a wedge-shaped tube portion 214 is inserted inside, and injection hose 104 is inserted into guide tube portion 211 through wedge-shaped tube portion 214, and injection hose 104 is fixed by the bite of lock claw 213. When injection hose 104 is to be pulled out, wedge-shaped tube portion 214 is pushed in to release the bite of lock claw 213 into injection hose 104, allowing injection hose 104 to be pulled out (see Patent Document 1).

[0004] Male arm lock coupling 220 is provided on the side of plug-in joint 210 opposite the attachment / detachment side of injection hose 104, is provided integrally with plug-in joint 210, and has an insertion tube portion 221, with an engagement recess 222 formed circumferentially on the outer periphery of insertion tube portion 221. Female arm lock coupling 230 has a substantially cylindrical base portion 231, an attachment tube portion 232 which is press-fitted into pressure feed hose 103, a lever 233 rotatably supported by base portion 231, and a cam-shaped engagement portion 234 which is provided integrally at the base of lever 233.

[0005] When connecting pressure feed hose 103 and injection hose 104 with joint mechanism 200, injection hose 104 is inserted into guide tube portion 211 through wedge-shaped tube portion 214, and injection hose 104 is fixed to plug-in joint portion 210 and male arm lock coupling 220 by the engagement of lock claws 213, and insertion tube portion 221 of male arm lock coupling 220 is inserted into base portion 231 of female arm lock coupling 230 attached to pressure feed hose 103, and lever 233 is tilted to engage and fix engagement portion 234 in engagement recess 222. The connected pressure feed hose 103 and injection hose 104 are communicated with each other via holes that communicate in the axial direction of plug-in joint portion 210, male arm lock coupling 220, and female arm lock coupling 230. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4394816 Summary of the Invention [Problem to be solved by the invention]

[0007] The connection between the pressure hose 103 and injection hose 104 of the mortar pressure pump 102 using the above-mentioned coupling mechanism 200 can be achieved with a single touch by inserting the injection hose 104 into the guide tube portion 211 and fixing it by the engagement of the lock claws 213, and the female arm lock coupling 230 and male arm lock coupling 220 attached to the pressure hose 103 can be fixed by tilting the lever 233, so that the pressure hose 103 and injection hose 104 can be easily connected.

[0008] However, when the pressure feed hose 103 and the injection hose 104 are connected with this joint mechanism 200, the pressure applied when injecting mortar may cause sand particles of the mortar to get into the installation location of the lock claw 213, even if the seal ring 212 of the plug-in joint part 210 is present. If the sand particles of the mortar get into the installation location of the lock claw 213, the lock claw 213 cannot be released from biting into the injection hose 104 even if the wedge-shaped tubular part 214 is pushed toward the lock claw 213, and the injection hose 104 cannot be removed from the plug-in joint part 210. If the injection hose 104 cannot be removed from the plug-in joint part 210, the plug-in joint part 210 and the male arm lock coupling 220, in other words the joint mechanism 200, cannot be reused, so there is a demand for a joint structure that allows the joint member to be reliably removed from the injection hose after mortar is injected.

[0009] The present invention has been proposed in consideration of the above-mentioned problems, and aims to provide a mortar injection joint structure that allows a mortar injection hose to be easily connected to a pressure hose of a mortar pressure pump, and allows the joint member to be easily and reliably removed from the injection hose after mortar injection, so that the joint member can be reliably reused for another mortar injection operation. [Means for solving the problem]

[0010] The mortar injection coupling structure of the present invention comprises a substantially cylindrical base, a mounting tube portion inserted so as to be pressed into the pressure hose of a mortar pressure pump, a lever tiltably supported on the base, a female arm lock coupling having a cam-shaped engaging portion integrally formed at the base of the lever, a base tube, a retaining hole communicating with the axial direction of the base tube at substantially the same diameter, and a male arm lock coupling provided on the outer periphery of the female arm lock coupling connection side of the base tube and having an engaging recess with which the engaging portion of the lever can be releasably engaged, and is characterized in that the base tube of the male arm lock coupling, with a mortar injection hose held in frictional contact by the retaining hole, is inserted into the base of the female arm lock coupling with the pressure hose inserted into the mounting tube portion, the engaging portion engages with the engaging recess to fix the female arm lock coupling and the male arm lock coupling, and a portion of the injection hose is positioned inside the pressure hose. According to this, the mortar injection hose and the pressure hose of the mortar pressure pump can be easily connected by simply inserting the mounting cylinder part of the female arm lock coupling into the pressure hose, inserting the injection hose into the holding hole of the male arm lock coupling so that it protrudes to the connection side and makes frictional contact, and engaging and connecting the female arm lock coupling and the male arm lock coupling with a lever. Also, since the injection hose is only held by frictional contact in the holding hole of the male arm lock coupling, the male arm lock coupling, which is a joint member, can be easily and reliably removed from the injection hose after mortar injection, and the male arm lock coupling or the combination of the male arm lock coupling and the female arm lock coupling can be reliably reused for another mortar injection operation.

[0011] The mortar injection joint structure of the present invention is characterized in that a seal ring is provided around the contact portion between the cylindrical base portion of the female arm lock coupling and the base cylinder of the male arm lock coupling inserted therein. According to this, when the pressure hose and injection hose are connected using a female arm lock coupling and a male arm lock coupling and mortar is pressurized and injected, mortar that has penetrated inside the pressure hose to the outside of the injection hose can be prevented from leaking out to the outside.

[0012] The mortar injection joint structure of the present invention is characterized in that a portion of the injection hose is loosely inserted inside the mounting tube portion, and a gap is provided between the injection hose and the mounting tube portion to allow mortar to enter. According to this, when the pressure feed hose and the injection hose are connected by the female arm lock coupling and the male arm lock coupling, and mortar is injected under pressure, the mortar enters the gap between the injection hose and the mounting cylinder portion that allows the mortar to enter, and the position retention force of the injection hose, which is held in position by the frictional force of the frictional contact of the retaining hole, can be increased by the pressing force and frictional force of the mortar that has entered under pressure into the gap that allows the mortar to enter, and the injection hose can be reliably prevented from coming out of the male arm lock coupling. Also, since the pressurized state of the mortar that has entered the gap that allows the mortar to enter is released after the mortar is injected under pressure, the retention force on the injection hose decreases, and the injection hose can be easily removed from the retaining hole of the male arm lock coupling. Effect of the Invention

[0013] According to the mortar injection joint structure of the present invention, the mortar injection hose and the pressure hose of the mortar pressure pump can be easily connected, and the joint member can be easily and reliably removed from the injection hose after mortar injection, allowing the joint member to be reliably reused for another mortar injection operation. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a front view of a mortar injection joint structure according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a longitudinal cross-sectional view of a mortar injection joint structure according to an embodiment. [Diagram 3]FIG. 2 is an explanatory diagram illustrating the construction of a mortar injection joint structure according to an embodiment. [Figure 4] FIG. 4 is a cross-sectional view illustrating the infiltration of pressurized mortar into a gap that allows the infiltration of mortar in a mortar injection joint structure according to an embodiment. [Diagram 5] 13 is a longitudinal cross-sectional view illustrating a case in which an injection hose slides in the mortar injection joint structure of the embodiment. FIG. [Figure 6] FIG. 2 is a diagram showing an injection test device using the mortar injection joint structure of the present invention. [Figure 7] FIG. 4 is a longitudinal cross-sectional view illustrating the mortar injection joint structure of a test example. [Figure 8] An explanatory diagram showing the driving of rock bolts and the injection of mortar into holes in the ground surrounding the tunnel space. [Figure 9] 13A and 13B are front views illustrating a connection mechanism for connecting a pressure hose and an injection hose in a conventional mortar injection system. [Figure 10] 4(a) and (b) are longitudinal cross-sectional views illustrating a connection mechanism for connecting a pressure hose and an injection hose in a conventional mortar injection. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Mortar injection joint structure of the embodiment] The mortar injection joint structure of an embodiment of the present invention is used, for example, in tunnel space T in Figure 8, when driving a rock bolt into a drilled hole 101 of a long pre-receiving work in the natural ground 100, and injecting mortar M around the rock bolt in the drilled hole 101, and also into a packer installed in the drilled hole 101 around the mouth of the drilled hole 101 in the case of a post-injection type rock bolt, or when driving a reinforcing material such as a rock bolt or a steel pipe into a drilled hole for a head reinforcement work, and injecting mortar M around the reinforcing material in the drilled hole, and connects a pressure delivery hose 103 of a mortar pressure delivery pump 102 that mixes and pressure-feeds mortar M to an injection hose 104 such as a nylon hose that injects mortar M into the drilled hole 101, etc.

[0016] As shown in Figures 1 to 3, the mortar injection joint structure of this embodiment comprises a female arm lock coupling 1 attached to a pressure hose 103 of a mortar pressure pump 102, and a male arm lock coupling 2 attached to an injection hose 104 that injects mortar M into a borehole 101, etc., where the female arm lock coupling 1 is a female joint member or coupler of a lever-detachable joint, and the male arm lock coupling 2 is a male joint member or adapter of a lever-detachable joint.

[0017] The female arm lock coupling 1 has a substantially cylindrical base 11, a donut-shaped abutment portion 12 provided at the end of the base 11 on the connection side of the pressure feed hose 103, and a mounting tube portion 13 inserted so as to be press-fitted into the pressure feed hose 103 of the mortar pressure feed pump 102, and the base 11, the abutment portion 12 and the mounting tube portion 13 are integrally formed or fixed integrally. The outer diameter of the mounting tube portion 13 is formed to be substantially the same as or slightly smaller than the inner diameter of the pressure feed hose 103, and the outer circumferential surface is provided with a non-slip shape for the inner surface of the pressure feed hose 103, and the pressure feed hose 103, which is press-fitted into the mounting tube portion 13 and externally inserted onto the mounting tube portion 13, is positioned so that its tip abuts against the surface of the abutment portion 12 on the pressure feed hose 103 side.

[0018] A pair of tongue-shaped journal portions 14, 14 are provided on the base 11 so as to protrude outward in the radial direction, and the pair of journal portions 14, 14 are provided at positions opposite each other in the radial direction. A lever 15 is disposed between each pair of journal portions 14, 14 on the base 11, and the lever 15 is journaled by the pair of journal portions 14, 14 so as to be tiltable. A cam-shaped engagement portion 16 is integrally provided at the base of each lever 15 so as to protrude inward.

[0019] The male arm lock coupling 2 has a base tube 21, and the base tube 21 is provided with a retaining hole 22 that communicates with the base tube 21 and has approximately the same diameter in the axial direction. The inner diameter of the retaining hole 22 is formed to be approximately the same as or slightly larger than the outer diameter of the injection hose 104, and a very small gap 4 is formed between the outer peripheral surface of the injection hose 104 inserted into the retaining hole 22 and the inner peripheral surface of the retaining hole 22. This gap 4 allows the injection hose 104 to slide relative to the base tube 21 when mortar injection work is not being performed, and when pressurized mortar enters the injection hose 104 during mortar injection work and the diameter of the injection hose 104 expands slightly, the inner peripheral surface of the retaining hole 22 comes into frictional contact with the outer peripheral surface of the injection hose 104, thereby maintaining the position of the injection hose 104 relative to the retaining hole 22.

[0020] The final holding force or friction force due to frictional contact between the inner surface of the retaining hole 22 and the outer surface of the injection hose 104 is appropriate as long as it is within a range in which the retaining hole 22 can hold the injection hose 104 in a fixed position when the mortar M is pressurized and injected by the mortar pressure pump 102 using a pressure force of the standard upper limit pressure, or the retaining hole 22 can hold the injection hose 104 so that it slides within an allowable range that allows mortar pressure injection through the injection hose 104 to be continued, and the injection hose 104 can be pulled out of the retaining hole 22 after mortar injection.

[0021] The above-mentioned standard upper limit pressure is preferably set to 4 MPa because the pressure required for repressurized injection to reliably fill the mortar M, including the upward drilling, is a maximum of 4 MPa. In order to suppress the sliding of the injection hose 104 held by the holding hole 22 relative to the holding hole 22 as shown in FIG. 5, the mortar pressure pump 102 used in the present invention is preferably one that has a rated pressure corresponding to the standard upper limit pressure of 4 MPa, for example, and automatically stops to avoid overload when pressurized operation is performed at or above the rated pressure. Alternatively, even if the sliding of the injection hose 104 relative to the holding hole 22 is permitted to some extent, when the rated pressure is set in the pressure pump 102 to avoid overloading the drive motor, it is required to ensure a sufficient protruding length from the holding hole 22 to the pressure hose 103 side so that the injection hose 104 does not completely slip out of the holding hole 22 until the rated pressure is reached.

[0022] A seal ring 23 is provided around the inner end of base tube 21 in the illustrated example so that a seal ring 23 is provided around the abutment portion between cylindrical base 11 of female arm lock coupling 1 and base tube 21 of male arm lock coupling 2 inserted therein, and the inner peripheral surface of seal ring 23 contacts the outer peripheral surface of injection hose 104, which is inserted into and held in holding hole 22, by pressing the outer peripheral surface of injection hose 104. Furthermore, when the male arm lock coupling 2 and female arm lock coupling 1 are connected, the surface of seal ring 23 on the abutment portion 12 side contacts abutment portion 12 by pressing abutment portion 12 in the axial direction.

[0023] A circumferential groove-like engagement recess 24 is formed on the outer periphery of the base tube 21 on the female arm lock coupling connection side, and when the male arm lock coupling 2 and the female arm lock coupling 1 are connected, the engagement recess 24 is adapted to engage with the engagement portion 16 provided on the lever 15 in a releasable manner.

[0024] When constructing the mortar injection joint structure of this embodiment, the mounting tube portion 13 of the female arm lock coupling 1 is inserted into the pressure feed hose 103 so as to be press-fitted, and the injection hose 104 is inserted into the retaining hole 22 of the male arm lock coupling 2 so that the end of the injection hose 104 protrudes a predetermined length.

[0025] Then, the base tube 21 of the male arm lock coupling 2, having a mortar M injection hose 104 inserted into the retaining hole 22 with a protruding state, is inserted into the base 11 of the female arm lock coupling 1, having a pressure feed hose 103 inserted into the mounting tube portion 13, and each lever 15 is tilted to engage the cam-shaped engagement portion 16 with the engagement recess 24, thereby fixing and connecting the female arm lock coupling 1 and the male arm lock coupling 2, thereby constructing the mortar injection joint structure of this embodiment.

[0026] In this mortar injection joint structure, a portion of injection hose 104 is disposed inside pressure feed hose 103, and injection hose 104 is communicated so as to be able to introduce mortar M pumped from pressure feed hose 103. In the illustrated example, the portion of injection hose 104 protruding from retaining hole 22 toward pressure feed hose 103 is mostly disposed inside mounting tube portion 13 inside pressure feed hose 103, and at least a portion of it is disposed inside pressure feed hose 103 so as to further protrude from mounting tube portion 13 toward the pressure feed pump 102.

[0027] Furthermore, in the mortar injection joint structure of this embodiment, the inner diameter of the mounting tube portion 13 is formed slightly larger than the outer diameter of the injection hose 104, and a gap 3 that allows mortar to enter is provided between the injection hose 104 and the mounting tube portion 13, and a part of the injection hose 104 is loosely inserted inside the mounting tube portion 13 (see FIG. 4). Mortar M enters under pressure into the gap 3 that allows mortar to enter, when the mortar is pressurized and injected, so that the positional retention force of the injection hose 104, which is retained in position by the frictional force of the frictional contact of the retaining hole 22, can be further increased by the mortar that has entered the gap 3 under pressure.

[0028] According to the mortar injection joint structure of this embodiment, the injection hose 104 for mortar M can be easily connected to the pressure hose 103 for the mortar pressure pump 102 by simply inserting the mounting tube portion 13 of the female arm lock coupling 1 into the pressure hose 103, inserting the injection hose 104 into the holding hole 22 of the male arm lock coupling 2 so that it protrudes to the connection side, and engaging and connecting the female arm lock coupling 1 and the male arm lock coupling 2 with the lever 15. Furthermore, since the injection hose 104 is simply inserted into the holding hole 22 of the male arm lock coupling 2, the male arm lock coupling 2, which is the joint member, can be easily and reliably removed from the injection hose 104 after mortar injection, and after necessary mortar M is washed away, the male arm lock coupling 2 or the combination of the male arm lock coupling 2 and the female arm lock coupling 1 can be reliably reused for another mortar injection operation.

[0029] In addition, by providing a seal ring 23 around the abutment portion between the cylindrical base 11 of the female arm lock coupling 1 and the base tube 21 of the male arm lock coupling 2 inserted therein, when the pressure feed hose 103 and the injection hose 104 are connected between the female arm lock coupling 1 and the male arm lock coupling 2 and mortar is pressurized and injected, mortar M that has penetrated to the outside of the injection hose 104 inside the pressure feed hose 103 can be prevented from leaking out to the outside.

[0030] Furthermore, by providing gap 3 between injection hose 104 and mounting cylinder portion 13 which allows mortar to enter, the position retention force of injection hose 104, which is held in position by the frictional force of frictional contact in retaining hole 22, can be increased by the pressing force and frictional force of mortar M which has entered under pressure into gap 3 which allows mortar to enter, making it possible to reliably prevent injection hose 104 from slipping out of male arm lock coupling 2. Furthermore, after pressurized injection of mortar M, the pressurized state of mortar M which has entered gap 3 which allows mortar to enter is released, so the retention force on injection hose 104 decreases and injection hose 104 can be easily removed from retaining hole 22 of male arm lock coupling 2.

[0031] [Scope of the invention disclosed herein] The invention disclosed in this specification includes, in addition to each invention, embodiment, and example listed as the invention, those specified by changing partial contents of these to other contents disclosed in this specification, those specified by adding other contents disclosed in this specification to these contents, or those specified by deleting partial contents of these to the extent that partial action and effect can be obtained, and specifying them as a higher conceptualization. The invention disclosed in this specification also includes the following contents and further modified examples described below.

[0032] For example, in the mortar joint structure of the above embodiment, in order to circumferentially mount the seal ring 23 at the contact portion between the cylindrical base 11 of the female arm lock coupling 1 and the base tube 21 of the male arm lock coupling 2 inserted therein, an example was described in which the seal ring 23 is fitted into the inner end of the base tube 21 on the male arm lock coupling 2 side and mounted so that the seal ring 23 can also press against the outer circumferential surface of the injection hose 104, but the seal ring 23 may also be mounted around the inner bottom portion of the base 11 of the female arm lock coupling 1.

[0033] In addition, for example, in the mortar injection joint structure of the above embodiment, a portion of the injection hose 104 is loosely inserted inside the mounting tube portion 13, and a gap 3 is provided between the injection hose 104 and the mounting tube portion 13 to allow mortar to enter, but the present invention also includes a mortar injection joint structure in which a portion of the injection hose is inserted so as to be in close contact with the inside of the mounting tube portion. The materials of the female arm lock coupling, male arm lock coupling, pressure feed hose, and injection hose in the present invention are appropriate within a range in which the required holding force by press-in or the required holding force by frictional contact can be obtained as the mortar injection joint structure of the present invention.

[0034] [Test example of mortar injection joint structure] A mortar pressure injection test was carried out using an injection test device equipped with the mortar injection joint structure of the embodiment (see Figs. 6 and 7). In this injection test device, the mortar injection joint structure of the embodiment, which is composed of a female arm lock coupling 1, a pressure feed hose 103, a male arm lock coupling 2, and a nylon injection hose 104, was installed, and a pressure gauge 111 was installed midway along the pressure feed hose 103 of the kneading pressure feed pump 102. Furthermore, a cylindrical section 112 corresponding to the natural ground drilling hole 101 was provided downstream of the injection hose 104, and a valve 113 was provided at the downstream end of the cylindrical section 112.

[0035] The nylon injection hose 104 in the injection test device had an outer diameter of 16 mm and an inner diameter of 13 mm, and the inner diameter of the holding hole 22 of the male arm lock coupling 2, which holds the injection hose 104, the outer diameter of which has expanded due to the pressure injection of mortar M, by frictional contact, was 16.4 mm. In addition, in the injection test device, the axial length L1 of the base tube 21 in FIG. 7 was 85 mm, and the insertion length L2 of the injection hose 104 protruding from the end of the base tube 21 on the pressure feed hose 103 side was 100 mm. The material to be injected was mortar M. And, the mortar M was pressure-injected to a maximum pressure of 4.67 MPa in Example 1, 5.09 MPa in Comparative Example 1, and 5.39 MPa in Comparative Example 2. The pumping speed of the mortar M in each example was 14 L / min. The test results are shown in Table 1.

[0036] [Table 1]

[0037] In Example 1, the injection hose 104 was maintained in a fixed position in the retaining hole 22, and the injection hose 104 did not come out of the retaining hole 22. Furthermore, since no mortar leakage occurred from the mortar injection joint structure, it is understood that pressurized injection of mortar through the injection hose 104 can be performed without problems. Furthermore, after the pressure pump 103 was stopped and the test was completed, the engagement and fixation between the female arm lock coupling 1 and the male arm lock coupling 2 was released, and the injection hose 104 was pushed once into the pressure hose 103 side in the male arm lock coupling 2 and washed with water to wash away the sand grains, whereby the injection hose 104 could be easily removed from the retaining hole 22.

[0038] In Comparative Example 1, a pressure of about 0.5 MPa was applied to the injection hose 104 at the start of pressurized injection of mortar, and the injection hose 104 slid about 1 to 2 cm into the retaining hole 22 and stopped. Finally, when a pressure of 5.09 MPa was applied, the injection hose 104 burst and the test ended. Until the injection hose 104 burst, there was no leakage of mortar from the mortar injection joint structure, and no coming off of the injection hose 104. In other words, it can be seen that, even in Comparative Example 2, pressurized injection of mortar through the injection hose 104 could be performed without any problems until the injection hose 104 burst.

[0039] In Comparative Example 2, injection hose 104 slid about 1 to 2 mm into retaining hole 22 and stopped. Finally, when a pressure of 5.39 MPa was applied, injection hose 104 burst and the test ended. Until injection hose 104 burst, there was no leakage of mortar from the mortar injection joint structure, and no coming off of injection hose 104. In other words, it can be seen that in Comparative Example 3 as well, pressurized injection of mortar could be performed via injection hose 104 without any problems until injection hose 104 burst.

[0040] The reason why the injection hose 104 stops after sliding and does not come off is thought to be that when the injection hose 104 slides, sand particles and cement particles in the mortar get into the gap 4 between the retaining hole 22 and the injection hose 104, causing them to get caught in the gap 4, creating resistance.

[0041] In addition, as the amount of sliding increases, the amount of sand grains and cement particles entering the gap 4 increases, so that the bite becomes stronger and a large resistance is generated.

[0042] It has also been confirmed that when a pressure of approximately 1.0 MPa is applied to injection hose 104, injection hose 104 expands and its outer diameter increases, eliminating gap 4 with retaining hole 22 and increasing frictional force.

[0043] If the pressure is further increased, injection hose 104 expands more, and the outer diameter of the portion of injection hose 104 not inserted into retaining hole 22 becomes larger than the inner diameter of retaining hole 22, so it is clear that no sliding occurs. [Industrial Applicability]

[0044] INDUSTRIAL APPLICABILITY The present invention can be utilized when connecting an injection hose for injecting mortar into a borehole in natural ground, etc., to a pressure-feed hose of a mortar pressure-feed pump. [Explanation of symbols]

[0045] 1...female arm lock coupling 11...base 12...contact portion 13...mounting tube portion 14...axial support portion 15...lever 16...engagement portion 2...male arm lock coupling 21...base tube 22...retaining hole 23...seal ring 24...engagement recess 3...gap to allow mortar to enter 4...gap 100...natural ground 101...drilling 102...mortar pressure pump 103...pressure hose 104...injection hose 111...pressure gauge 112...tubular portion 113...valve 200...coupling mechanism 210...insertion type coupling portion 211...guide tube portion 212...seal ring 213...locking claw 214...wedge-shaped tube portion 220...male arm lock coupling 221...insertion tube portion 222...engagement recess 230...female arm lock coupling 231...base 232: Mounting tube portion 233: Lever 234: Engagement portion T: Tunnel space M: Mortar

Claims

1. a female arm lock coupling having a generally cylindrical base, a mounting cylinder that is inserted so as to be press-fitted onto a pressure hose of a mortar pressure pump, a lever that is pivotally supported on the base so as to be tiltable, and a cam-shaped engagement portion that is integrally provided at the base of the lever; a male arm lock coupling provided on an outer periphery of the base tube on the female arm lock coupling connection side and having an engagement recess with which the engagement portion of the lever can be releasably engaged, The base tube of the male arm lock coupling, with a mortar injection hose held in frictional contact with the holding hole, is inserted into the base of the female arm lock coupling, with the pressure feed hose inserted into the mounting tube portion, The engaging portion is engaged with the engaging recess to fix the female arm lock coupling and the male arm lock coupling, A mortar injection joint structure, characterized in that a portion of the injection hose is disposed inside the pressure feed hose.

2. 2. A mortar injection joint structure according to claim 1, characterized in that a seal ring is provided around the abutment portion between the cylindrical base portion of the female arm lock coupling and the base cylinder of the male arm lock coupling inserted therein.

3. A portion of the injection hose is loosely inserted into the mounting tube portion, 3. The mortar injection joint structure according to claim 1, wherein a gap is provided between the injection hose and the mounting tube portion to allow mortar to enter.

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