JP6762154B2 - Lock bolt head fixing tool - Google Patents

Description

The present invention relates to a fixing tool for the head of a lock bolt inserted in the ground for fixing an excavated portion in tunnel construction.

Conventionally, in mountain tunnel construction represented by the NATM method, concrete is sprayed on the excavated wall surface at each excavation due to blasting, and a large number of lock bolts are inserted into the ground perpendicular to the tunnel wall surface. It is known that after fixing the ground with sprayed concrete and rock bolts as the main support, a waterproof sheet is laid on the outer surface of the ground to perform the final concrete lining.

Conventionally, as shown in FIG. 15, the rock bolt 51 of M24 has a bore hole 52 having a diameter of about 45 mm and a depth of 3 to 4 m with respect to the sprayed concrete surface for fixing the ground by the lock bolt. Is drilled in the ground, the ground material 53 is filled in the bore hole 52, and then the lock bolt 51 is inserted and fixed to the ground, and the seat plate 54 such as a washer is attached to the head of the lock bolt 51. A fixing tool 50 for screwing and fixing the nut 55 from the outer surface side was used.

In such a conventional fixing tool 50, since the nut 55 is fixed to the outer surface side of the seat plate 54, the protruding length from the sprayed concrete surface to the head of the lock bolt 51 is at least about 3 cm, and the protruding lock bolt The head of 51 could damage the tarpaulin when placing the lining concrete. For this reason, in the conventional fixing tool 50, as shown in FIG. 15, in order to prevent damage to the waterproof sheet, a lock having a bowl shape or the like so as to surround the entire seat plate 54 including the lock bolt head. It was common to attach the bolt cover 56.

As a technique for shortening the protruding length of the lock bolt in the fixed state, the following Patent Document 1 describes a shaft portion that can be loosely inserted into the hole of the seat plate and a head that is fixed to the hand side of the shaft portion and is larger than the hole of the seat plate. A lock bolt nut is described in which a female thread portion having a predetermined length is formed so as to be continuous from the head portion to the shaft portion. Further, in Patent Document 2 below, a nut that is inserted from one end side into a hole of a bearing plate and fits in a relative non-rotatable manner, and a nut that is integrally on the other end side and gradually decreases in diameter toward the tip end. A lock bolt nut with a tapered collar that supports the bearing plate on the back of the rear end is described. Further, Patent Document 3 below includes a screw portion that is screwed with a screw portion formed on the outer circumference of the lock bolt so as to penetrate from the head to the shaft portion, and is further fitted to the outer circumference of the shaft portion to be fitted from the shaft portion. Described is a lock bolt nut provided with a hollow cap having a protruding tip hole diameter substantially equal to the lock bolt diameter.

Japanese Patent No. 3101180 Japanese Patent No. 3540063 Japanese Patent No. 321294

Since the lock bolt nuts described in Patent Documents 1 to 3 have a shorter protruding length in the fixed state than the conventional nuts, a tarpaulin is used when placing the lining concrete without attaching the lock bolt cover described above. Although the risk of damage to the lock bolt is reduced, the lock bolt head and nut do not stop protruding from the outer surface of the seat plate, and they still protrude not a little, so problems such as damage to the tarpaulin could not be completely solved. Absent.

On the other hand, as shown in FIG. 15, in the conventional fixing tool 50 to which the above-mentioned lock bolt cover 56 is attached, since the lock bolt cover 56 protrudes greatly from the sprayed concrete surface, the following (1) to (4) and the like There was a problem.
(1) This protrusion easily damages the tarpaulin when placing lining concrete.
(2) Restraint cracks due to these protrusions are likely to occur during drying shrinkage after placing lining concrete. That is, the back surface of the lining concrete is restrained by the unevenness of the protruding portion, cannot follow the drying shrinkage, and cracks occur.
(3) The tarpaulin does not adhere to the sprayed concrete surface Due to improper laying of the tarpaulin, cavities are likely to form on the back surface of the lining concrete.
(4) The thickness (rolling thickness) of the lining concrete is partially insufficient.

Therefore, the main problem of the present invention is firstly that the lock bolt head and the nut are basically not projected from the outer surface of the seat plate to prevent damage to the waterproof sheet and to prevent cracks in the lining concrete. It is an object of the present invention to provide a fixing tool for a lock bolt head, in which a cavity is not formed on the back surface of the lining concrete and the partial winding thickness of the lining concrete is eliminated.

Secondly, the lock bolt head and nut are basically prevented from protruding from the outer surface of the seat plate, but when the tension force is introduced to the lock bolt, the lock bolt head slightly protrudes from the outer surface of the seat plate. Even in this case, it is an object of the present invention to provide a fixing tool for a lock bolt head to which a nut cap is attached, which can prevent damage and cracks of the waterproof sheet, prevention of cavities, etc. by alleviating this step.

Thirdly, a seat plate frame is attached to the outer peripheral edge of the seat plate to prevent damage to the waterproof sheet, cracks, and cavities by alleviating the stepped steps caused by the thickness of the seat plate. The purpose is to provide a fixing tool for the head of a lock bolt.

In order to solve the first problem, as the present invention according to claim 1, a seat plate having an opening formed to be inserted into a lock bolt inserted in the ground and a female screw portion screwed into the lock bolt. In the fixing tool for the head of the lock bolt, which is formed of a nut that is fixed to the seat plate.
The peripheral surface of the opening is a tapered inclined surface that expands outward over the entire circumference, and the engagement surface of the nut with the opening is tapered in the direction opposite to the opening. The nut is fitted into the opening and fixed in an inclined state, and the outer surface of the nut and the end surface of the lock bolt head are substantially the same with respect to the outer surface of the seat plate. A lock bolt head fixture is provided, characterized in that it is.

In the invention according to claim 1, in the lock bolt head fixing tool in which the seat plate and the nut are fixed to the lock bolt head, the peripheral surface of the opening formed in the seat plate is outside over the entire circumference. It is a tapered inclined surface that expands toward, and the engaging surface of the nut with the opening is a tapered inclined surface opposite to the opening. In the fixed state, the nut fits into the opening of the seat plate, and the inclined surface of the opening and the inclined surface of the nut are engaged and fixed. Then, with reference to the outer surface of the seat plate, the outer surface of the nut and the end surface of the lock bolt head are substantially the same surface. Therefore, in the fixing tool according to the present invention, since the lock bolt head and the nut do not protrude from the outer surface of the seat plate, damage to the waterproof sheet can be completely prevented when the waterproof sheet is laid and when the lining concrete is placed. Further, since the lining concrete is not restrained by the unevenness, the lining concrete is not restrained and cracked. Further, since the outer surface of the seat plate is not formed with irregularities, the waterproof sheet is laid in close contact with the outer surface, and no cavity is formed on the back surface of the lining concrete. In addition, the partial winding thickness shortage of the lining concrete does not occur.

The present invention according to claim 2 provides the lock bolt head fixing tool according to claim 1, wherein the female threaded portion of the nut extends from the seat plate to the ground side.

In the invention according to claim 2, the female screw portion of the nut is formed so as to extend from the seat plate to the ground side, so that the screwing dimension (fitting length) between the lock bolt and the nut can be adjusted to the seat plate plate. It can be taken longer than the thickness, and the pull-out resistance of the threaded portion can be sufficiently secured.

The lock according to claim 3, wherein the angle formed by the line extending the inclined surface of the opening to the outside and the outer surface of the seat plate is 30 ° to 70 °. A fixing tool for the bolt head is provided.

In the invention according to claim 3, by setting the inclination angle of the inclined surface formed on the peripheral surface of the hole to 30 ° to 70 °, the strength when the seat plate and the nut are engaged is ensured. ing.

The lock bolt according to any one of claims 1 to 3, wherein the inclined surface of the opening is formed in a linear taper shape that is linearly inclined over the entire length of the inclined surface according to the fourth aspect of the present invention. A head fixer is provided.

In the invention according to claim 4, the seat plate and the nut are formed by forming the inclined surface of the opening and the inclined surface of the nut in a linear taper shape that is linearly inclined over the entire length of the inclined surface, respectively. The strength at the time of engagement with is secured.

In order to solve the second problem, as the present invention according to claim 5, the nut is installed so as to cover the outer surface of the nut, and an inclined surface in the downward direction toward the outer surface of the seat plate is formed on the outer peripheral portion. The lock bolt head fixing tool according to any one of claims 1 to 4 is provided, which comprises a nut cap having a recessed portion formed on the inner surface side so that the upper end of the lock bolt head can be fitted.

In the invention according to claim 5, even if the head of the lock bolt slightly protrudes from the outer surface of the seat plate, the waterproof sheet can be prevented from being damaged, cracked, or cavities can be prevented by alleviating this step. It is something like that. Specifically, it is installed so as to cover the outer surface of the nut, an inclined surface in the downward direction toward the outer surface of the seat plate is formed on the outer peripheral portion, and the upper end of the lock bolt head is fitted on the inner surface side. It is provided with a nut cap having a recessed portion that can be fitted. By attaching this nut cap, even if the lock bolt head slightly protrudes from the outer surface of the seat plate, it is possible to eliminate the stepped step due to the lock bolt head and make it an inclined surface, so that the above-mentioned effect can be obtained. It becomes possible to play.

According to the sixth aspect of the present invention in order to solve the third problem, the frame material is installed so as to surround the outer peripheral portion of the seat plate, and is inclined downward toward the outer peripheral portion. The lock bolt head fixing tool according to any one of claims 1 to 5, further comprising a surface-formed seat plate mounting frame.

In the invention according to claim 6, the waterproof sheet can be prevented from being damaged, cracked, and cavities can be prevented by alleviating the stepped step caused by the thickness of the seat plate on the outer peripheral edge of the seat plate. It was made like this. Specifically, it is a frame material installed so as to surround the outer peripheral portion of the seat plate, and by attaching a seat plate mounting frame having an inclined surface in the downward direction toward the outer side formed on the outer peripheral portion. Since the stepped step formed on the outer peripheral edge can be eliminated by the thickness of the seat plate to form an inclined surface, the above-mentioned effect can be obtained.

As the present invention according to claim 7, the seat plate mounting frame is provided with the lock bolt head fixing tool according to claim 6, which is made of a plastic material.

According to the seventh aspect of the present invention, the material of the seat plate mounting frame is plastic. When the material is plastic, it is easy to manufacture, the weight is not increased, and the handleability is improved. It is desirable that the plastic seat plate mounting frame be previously attached to the seat plate with an adhesive or the like.

As described in detail above, according to the present invention according to claims 1 to 4, since the lock bolt head and the nut do not protrude from the outer surface of the seat plate, damage to the tarpaulin can be prevented and restraint cracks in the lining concrete can be prevented. It is suppressed, the cavity is not formed on the back surface of the lining concrete, and the partial winding thickness shortage of the lining concrete can be eliminated.

Further, according to the fifth aspect of the present invention, even if the head of the lock bolt is unavoidably slightly protruded from the outer surface of the seat plate, by alleviating this step, the waterproof sheet can be prevented from being damaged or cracked, and the cavity can be prevented. It will be possible to prevent the occurrence.

Further, according to the present invention according to claims 6 and 7, the waterproof sheet is prevented from being damaged or cracked, and a cavity is formed by alleviating a stepped step caused by the thickness of the seat plate on the outer peripheral edge portion of the seat plate. It will be possible to prevent the occurrence.

It is sectional drawing which shows the fixing state of the lock bolt 2 by the fixing tool 1 which concerns on 1st Embodiment of this invention. It is a top view of FIG. It is sectional drawing which shows the assembly procedure of the fixing tool 1. It is sectional drawing (the 1) which shows the fixing tool 1 which concerns on the modification. It is sectional drawing (the 2) which shows the fixing tool 1 which concerns on the modification. It is sectional drawing which shows the construction state of the waterproof sheet 23 and the lining concrete 24. It is a nut plan view which shows the example of another tool engaging part 12 for retightening or removing a nut 5. It is an overall perspective view of the fixing tool 1 which concerns on 2nd form example. It is sectional drawing which shows the fixing state of the lock bolt 2 by the fixing tool 1. It is the plan view. The nut cap 13 is shown, (A) is an upper surface side perspective view, and (B) is a lower surface side perspective view. It is sectional drawing which shows the tensile test structure of the fixing tool 1. It is sectional drawing which shows the tensile test structure of the conventional fixing tool. It is a graph which shows the test result. It is sectional drawing which shows the construction state using the conventional fixing tool 50.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Example of first form]
As shown in FIGS. 1 to 3, the lock bolt head fixing tool 1 according to the present invention includes a seat plate 3 having an opening 4 formed through the lock bolt 2 inserted in the ground and a seat plate 3 formed therein. A female threaded portion 6 screwed into the lock bolt 2 is formed, and is composed of a nut 5 fixed to the seat plate 3. In the description of this embodiment, the outer or outer surface and the outer surface side refer to the direction or surface of the tunnel inner air side, and the inner or inner surface and the inner surface side refer to the direction or surface of the ground side.

As the lock bolt 2, a conventionally known one having a male screw portion 2a formed at a protruding side end portion made of steel, reinforced fiber plastic, resin or the like can be used. The lock bolt 2 has a base end side in the bore hole 21 in a state where the end portion of the male screw portion 2a protrudes outward by a predetermined length (approximately the thickness of the seat plate 3) from the surface of the sprayed concrete 20. It is buried.

In mountain tunnel excavation work represented by the NATM method, the drilling is performed in the order of filling hole drilling → charging → blasting → slipping → concrete spraying → rock bolt drilling and placing. As shown in FIGS. 1 and 3, the drilling / driving work of the lock bolt 2 is performed by drilling a single pipe, double pipe, or self-drilling lock bolt using a drilling machine. After drilling the bore hole 21 of a predetermined depth, the grout material 22 is injected, the lock bolt 2 is inserted to fix the bore hole 21 to the ground, and then the seat plate 3 and the nut 5 are attached to the head. It is performed in the process of performing partial processing and completing the driving work of the lock bolt 2. The grout material 22 may be injected with the lock bolt 2 inserted in the bore hole 21.

As shown in FIGS. 1 to 3, the seat plate 3 is a square or circular metal flat plate, and is formed with an outer dimension larger than that of the bore hole 21 drilled in the ground. In the central portion of the seat plate 3, there is an opening 4 through which the male screw portion 2a of the lock bolt 2 can be inserted and the nut 5 screwed into the lock bolt 2 penetrates in the thickness direction. It is formed.

The opening 4 is a tapered inclined surface 7 whose peripheral surface expands toward the outside (end side of the lock bolt 2) over the entire circumference. The inclined surface 7 is formed over the entire plate thickness of the seat plate 3 so that the peripheral surface of the opening 4 does not have a vertical surface. That is, the inclined surface 7 is formed in a continuous tapered shape from the opening edge on the ground side of the opening 4 to the outer opening edge.

As shown in FIG. 1, the angle θ formed by the line extending the inclined surface of the opening 4 to the outside and the outer surface of the seat plate 3 of the inclined surface 7 is 30 ° to 70 °, preferably 40 °. It is better to form it so that it is ~ 60 °. If θ is smaller than 30 °, the strength of the seat plate 3 and the nut 5 that fits into the opening 4 may decrease, and if θ is larger than 70 °, the engagement between the seat plate 3 and the nut 5 may decrease. It is difficult to obtain sufficient strength.

As shown in FIGS. 1 and 3, the inclined surface 7 can be formed in a linear taper shape that is linearly inclined over the entire length of the inclined surface 7. In this case, the strength of the seat plate 3 and the nut 5 at the time of engagement can be relatively high. The spatial shape in the opening 4 at this time is a truncated cone.

Further, as shown in FIG. 4, the inclined surface 7 may be formed in a partially spherical shape that bulges toward the ground side or the outside. In this case, when the shaft core of the lock bolt 2 and the plane direction of the seat plate 3 are not orthogonal to each other, the engagement angle between the nut 5 and the opening 4 can be adjusted if there is a certain angle. , It will be possible to absorb construction errors. The inclination angle θ when the inclined surface 7 is formed in a partially spherical shape is a line extending outward from a straight line connecting the ground-side edge and the outer edge of the opening 4, and the outer surface of the seat plate 3. You can take the angle formed by.

As shown in FIG. 1, the inclined surface 7 of the opening 4 is formed so that the opening edge on the ground side has a diameter smaller than that of the bore hole 21 and the outer opening edge has a diameter larger than that of the bore hole 21. It is preferable to do so. As a result, the bore hole 21 can be closed by the seat plate 3, and the axial force of the lock bolt 2 can be easily transmitted to the sprayed concrete 20 through the nut 5 and the seat plate 3, so that the lock bolt 2 and the sprayed concrete 20 are easily transmitted. You will be able to achieve a certain unity with.

Next, the nut 5 is a metal member in which the female screw portion 6 penetrating the ground side and the outside is formed in the central portion, as shown in detail in FIG. 3, and the seat plate 3 is opened. It is formed in a size that can be fitted into the hole 4. At the end portion on the outer side in the axial direction, a collar portion 8 projecting outward in the radial direction is formed over the entire circumference, and the collar portion 8 is in a fixed state, as shown in FIG. It is fixed in the opening 4 of the. The outer end face and the ground side end face of the nut 5 are each formed to be substantially flat.

The nut 5 has a tapered inclined surface 9 whose engagement surface with the opening 4 is opposite to that of the opening 4. That is, the inclined surface 9 of the nut 5 and the inclined surface 7 of the seat plate 3 are formed so as to face each other in a state where the nut 5 is fitted and fixed in the opening 4 of the seat plate 3.

The inclined surface 9 of the nut 5 is formed in a tapered shape opposite to the inclined surface 7 of the seat plate 3 so as to face the inclined surface 7 of the seat plate 3 in the fixed state shown in FIGS. 1 and 4. Has been done. Specifically, as shown in FIG. 1, the inclined surface 7 of the seat plate 3 has a linear taper shape in which the angle formed by the line extending the inclined surface 7 to the outside and the outer surface of the seat plate 3 is θ. When formed, the inclined surface 9 of the nut 5 is formed in a linear taper shape in which the angle formed by the inclined surface 9 and the outer end surface of the nut is θ. Further, as shown in FIG. 4, when the inclined surface 7 of the seat plate 3 is formed in a partially spherical shape that bulges and curves toward the ground, the inclined surface 9 of the nut 5 bulges and curves toward the ground. It is formed in a partially spherical shape.

The flange portion 8 of the nut 5 is formed at a height substantially equal to the thickness of the seat plate 3. As a result, in the fixed state shown in FIG. 1, the flange portion 8 of the nut 5 is housed in the opening 4 of the seat plate 3 so as not to protrude outward from the outer surface of the seat plate 3.

The nut 5 may be formed with an extending portion 10 extending from the collar portion 8 to the ground side so that the female screw portion 6 extends from the seat plate 3 to the ground side. .. As a result, the screwing dimension (fitting length) between the nut 5 and the lock bolt 2 can be made larger than the plate thickness of the seat plate 3, and the required pull-out yield strength for design (for example, about 180 kN in the case of the lock bolt 2 of M24). ) Can be secured.

The outer circumference of the extending portion 10 is formed in a circular shape so that the opening 4 of the seat plate 3 can be inserted. The extending portion 10 is formed with a wall thickness that is substantially equal to or greater than the minimum wall thickness of the hexagon nut corresponding to the nominal diameter of the female screw portion 6. For example, in the case of the lock bolt 2 having a nominal diameter of M24, the minimum wall thickness of the hexagon nut corresponding to this nominal diameter is about 6 mm, so that the wall thickness of the extending portion 10 is preferably 6 mm or more.

The extending portion 10 may be provided as needed, and if sufficient mechanical strength can be secured only by the screwing dimensions of the lock bolt 2 and the nut 5 corresponding to the wall thickness of the seat plate 3, FIG. As shown in the above, it is not necessary to provide the extending portion 10 extending to the ground side from the seat plate 3. In this case, the nut 5 is housed in the opening 4 of the seat plate 3 in a fixed state, and is provided so as not to protrude from the outer surface of the seat plate 3 and the side surface of the ground.

As shown in FIGS. 1 and 2, a tool engaging portion 11 for tightening or removing the nut 5 by using a tool is formed on the outer end surface of the nut 5. preferable. In the illustrated example, a plurality (4) grooves extending in the radial direction are formed at intervals in the circumferential direction, the tip of the special tool is engaged with the grooves, and the nut 5 is rotated in the tightening direction or the removing direction. Can be retightened or removed. As the tool engaging portion, as shown in FIG. 7, four holes formed at the top, bottom, left, and right positions may be provided as the tool engaging portion 12.

As shown in FIG. 3, the fixing tool 1 is attached by inserting the opening 4 of the seat plate 3 into the head of the lock bolt 2 buried in the ground and locking the female screw portion 6 of the nut 5. This is done by screwing the bolt 2 into the male threaded portion 2a and fitting the nut 5 into the opening 4 of the seat plate 3.

After finishing the head treatment of the lock bolt 2 by the fixing tool 1, as shown in FIG. 6, a waterproof sheet 23 is laid on the outer surface thereof, and the final lining concrete 24 is placed.

In the present fixing tool 1, as shown in FIG. 1, the nut 5 is fitted and fixed in the opening 4 of the seat plate 3 in the fixed state, and the nut 5 is fixed with reference to the outer surface of the seat plate 3. The outer end face and the end face of the lock bolt 2 head are substantially the same. Approximately the same surface means that the outer end surface of the nut 5 is fixed within a range of ± 3 mm or less, preferably ± 2 mm or less in the thickness direction of the seat plate 3 with respect to the outer surface of the seat plate 3, and the outside of the nut 5 is formed. The end face of the lock bolt 2 protrudes about one mountain from the end face, and the end face of the lock bolt 2 protrudes from the outer surface of the seat plate 3 in the thickness direction of the seat plate 3 within a range of ± 3 mm or less, preferably ± 2 mm or less. It means to be fixed in. The meaning of "the end face of the lock bolt 2 protrudes by about one mountain with respect to the outer end face of the nut 5" is that the male screw portion 2a of the lock bolt 2 and the female screw portion 6 of the nut 5 are in mesh with each other. In order to have the maximum tensile strength, it is necessary that the male threaded portion 2a of the lock bolt 2 is firmly engaged with the total length of the female threaded portion 6 of the nut 5. Therefore, in order to firmly engage all the threads of the lock bolt 2 with the threads of the nut 5, the end face of the lock bolt 2 is projected and fixed by about one thread with respect to the outer end face of the nut 5. is there.

In the present fixing tool 1, the outer end surface of the nut 5 and the end surface of the lock bolt 2 head are aligned with the outer surface of the seat plate 3 instead of separately attaching a cover material that is substantially the same surface as the outer surface of the seat plate 3. As a result, since the surface of the seat plate 3 is substantially the same as the outer surface, the number of member points can be reduced, the construction work can be reduced, and high strength against pressure from the outside can be obtained.

As a result, as shown in FIG. 6, when the waterproof sheet 23 is laid and the lining concrete 24 is placed after the head treatment step of the lock bolt 2 by the fixing tool 1, when the lining concrete 24 is placed, the seat plate 3 is viewed from the outer surface. Since the head of the lock bolt 2 and the nut 5 do not protrude, damage to the waterproof sheet can be completely prevented. Further, since the head portion of the lock bolt 2 and the nut 5 are not significantly recessed with respect to the outer surface of the seat plate 3, the recessed portion does not form a cavity on the back surface of the lining concrete.

Further, since the outer surface of the seat plate 3 is not formed with irregularities, the lining concrete is not restrained by the irregularities, and the lining concrete is not restrained and cracked. That is, in the conventional fixing tool, as shown in FIG. 10, since the lock bolt head protrudes more than the outer surface of the seat plate, the back surface of the lining concrete is restrained by this protruding portion and cannot follow the drying shrinkage. , While cracks may occur, in the present fixing tool 1, such restraint cracks do not occur.

Further, since unevenness is not formed on the outer surface of the seat plate 3, the waterproof sheet is laid in close contact with the sprayed concrete surface and the outer surface of the seat plate, and it is possible to prevent the formation of cavities on the back surface of the lining concrete.

Further, since the protruding portion that greatly protrudes from the outer surface of the seat plate 3 is not formed, the partial winding thickness of the lining concrete is not insufficient, and the uniform strength of the lining concrete can be ensured.

[Example of second form]
As described above, it is desirable that the outer end surface of the nut 5 and the end surface of the lock bolt 2 head are substantially the same as the outer surface of the seat plate 3 with respect to the head of the lock bolt 2. Depending on the degree of introduction and the fixing error, it is expected that the head of the lock bolt 2 slightly protrudes toward the outer surface of the seat plate 3. As a countermeasure in this case, as shown in FIG. 8, a nut cap 13 can be installed on the outer surface of the seat plate 3 so as to cover the lock bolt head.

As shown in detail in FIG. 11, the nut cap 13 has a flat outer surface 13A, an inner surface 13B parallel to the outer surface 13A, and an outer peripheral edge of the outer surface 13A and an outer peripheral edge of the inner surface 13B on the outer peripheral portion. A truncated cone-shaped member that is close to a plate shape and has an inclined surface 13C formed in the downward direction toward the outer surface of the seat plate 3 so as to connect the seat plate 3 to the inner surface 13B. A recessed portion 13D into which the upper end of the portion can be fitted is formed. Therefore, by installing the nut cap 13 so as to cover the lock bolt 2, even if the head of the lock bolt 2 slightly protrudes to the outer surface side, the stepped step due to the lock bolt head is eliminated. It becomes possible to make the surface inclined, and it becomes possible to prevent damage to the waterproof sheet, cracks, prevention of cavities, and the like. In the drawing, the tool engaging portion 12 of the nut 5 is a hole type formed in a cross direction, and four protrusions on the inner surface side of the nut cap 13 are respectively fitted to the hole type tool engaging portion 12. 13a is formed.

Further, in the second embodiment, a seat plate mounting frame 14 is installed on the outer peripheral edge of the seat plate 3 in order to alleviate a stepped step caused by the thickness of the seat plate 3. Specifically, as shown in FIGS. 8 to 10, it is a frame material installed so as to surround the outer peripheral portion of the seat plate 3, and is an inclined surface in the downward direction toward the outer peripheral portion on the outer peripheral portion. A seat plate mounting frame 14 on which 14a is formed is installed. By eliminating the stepped step caused by the thickness of the seat plate 3 on the outer peripheral edge of the seat plate 3 and forming it as an inclined surface, it becomes possible to prevent damage and cracks of the waterproof sheet, prevent cavities, and the like. ..

As the seat plate mounting frame 14, one manufactured of a plastic material is preferably used from the viewpoint of manufacturability, weight, and handleability. In addition, it is desirable to attach the seat plate 3 to the seat plate 3 in advance with an adhesive or the like.

[Tensile test]
Next, the outline of the tensile test of the lock bolt will be described.

Tensile tests of lock bolts based on JIS M2506 were performed on the fixing tool 1 and the conventional fixing tool according to the present invention, respectively. FIG. 12 is a cross-sectional view showing the tensile test structure of the present fixing tool 1, and FIG. 13 is a cross-sectional view showing the tensile test structure of the conventional fixing tool. As shown in FIG. 12, the test apparatus according to the present fixing tool 1 has an external dimension of 150 × 150 × 9 (t) mm in a pedestal 30 provided with an opening having a diameter D = 74 mm, and has a maximum diameter. It has a structure in which the lock bolt 2 of M24 is fixed by a seat plate 3 having an opening 4 having a diameter of φ = 45 mm and an inclination angle of θ = 45 ° and a nut 5 having a maximum diameter of φ = 45 mm and a height of H = 25 mm. are doing. Further, as shown in FIG. 13, the conventional test device for the fixing tool has an external dimension of 150 × 150 × 9 (t) mm on a pedestal 30 ′ provided with an opening having a diameter D ′ = 56 mm. It has a structure in which the lock bolt 2 of M24 is fixed by a seat plate and a hexagon nut for M24. In the test, the displacement when an axial tensile load was applied to the lock bolt was measured using the above test apparatus.

FIG. 14 is a graph showing the relationship between load and displacement. It was found that the fixing tool 1 according to the present invention has a maximum load of about 230 kN and has a sufficient mechanical strength of about 180 kN or more, which is the proof stress required for the lock bolt 2 of the M24.

1 ... Lock bolt head fixing tool, 2 ... Lock bolt, 3 ... Seat plate, 4 ... Opening hole, 5 ... Nut, 6 ... Female thread part, 7 ... Inclined part, 8 ... Flange part, 9 ... Inclined part, 10 ... Extension part, 11/12 ... Tool engagement part, 13 ... Nut cap, 14 ... Seat plate mounting frame, 20 ... Sprayed concrete, 21 ... Bolt hole, 22 ... Grout material, 23 ... Tarpaulin, 24 ... Lining concrete

Claims (7)

A lock consisting of a seat plate having an opening for being inserted into a lock bolt inserted in the ground, a female screw portion screwed into the lock bolt, and a nut fixed to the seat plate. In the bolt head fixing tool
The peripheral surface of the opening is a tapered inclined surface that expands outward over the entire circumference, and the engagement surface of the nut with the opening is tapered in the direction opposite to the opening. The nut is fitted into the opening and fixed in an inclined state, and the outer surface of the nut and the end surface of the lock bolt head are substantially the same with respect to the outer surface of the seat plate. A lock bolt head fixing tool that is characterized by being The fixing tool for a lock bolt head according to claim 1, wherein the female threaded portion of the nut extends from the seat plate to the ground side. The lock bolt head fixing tool according to any one of claims 1 and 2, wherein the angle formed by the line extending the inclined surface of the opening to the outside and the outer surface of the seat plate is 30 ° to 70 °. The fixing tool for a lock bolt head according to any one of claims 1 to 3, wherein the inclined surface of the opening is formed in a linear taper shape that is linearly inclined over the entire length of the inclined surface. A recessed portion that is installed so as to cover the outer surface of the nut, has an inclined surface in the downward direction toward the outer surface of the seat plate on the outer peripheral portion, and can fit the upper end of the lock bolt head on the inner surface side. The lock bolt head fixing tool according to any one of claims 1 to 4, further comprising a nut cap on which the head is formed. Any of claims 1 to 5, which is a frame material installed so as to surround the outer peripheral portion of the seat plate, and includes a seat plate mounting frame having a downwardly inclined surface formed in the outer peripheral portion in the downward direction. Lock bolt head fixing tool described in. The fixing tool for a lock bolt head according to claim 6, wherein the seat plate mounting frame is made of a plastic material.

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