JP7105533B2 - Construction method of drill bit and post-installed anchor - Google Patents

Description

The present invention provides a drill bit and a post-installed anchor that can form a tapered enlarged diameter hole near the bottom of the hole when forming a hole for installing a post-installed anchor in an existing structure such as a road. Regarding the method.

Conventionally, there is a drill bit disclosed in Patent Document 1 as a drill bit capable of forming a tapered enlarged diameter hole portion near the bottom of a hole when forming a hole in an existing structure. This drill bit drills a straight hole first with a cutter blade for straight hole processing at the tip, and drills a pilot hole with a cutter blade for undercut processing in a non-expanding state so as to expand the diameter of the straight hole. At the same time, when the depth of the pilot hole reaches a predetermined depth, the diameter of the cutter blade for undercut processing is expanded by swinging projection to form a tapered enlarged diameter hole portion at the tip near the straight hole. is.

The hook portion of the undercutting cutter blade is engaged with the receiving locking portion at the lower end of the operating rod, and the undercutting cutter blade is normally put into an unexpanded state by the action of a force that pulls up the operating rod. When machining a tapered enlarged diameter hole, by pushing down the operating rod, the diameter of the undercut machining cutter blade, whose hook is engaged with the receiving locking part, is swung and enlarged. (See paragraphs [0067] to [0073] and FIGS. 39 to 41 of Patent Document 1).

JP 2008-183707 A

By the way, in the drill bit of Patent Document 1, during repeated diameter-expansion drilling, a movable portion composed of a hook portion of a cutter blade for undercutting (diameter-expansion cutter blade) and a receiving/locking portion of an operation rod is formed. There is a problem that chips are clogged in the part, and eventually the cutter blade for diameter expansion cannot return to its original position, and the drill bit cannot be pulled out. Especially when the base material to be drilled is asphalt, the bit blade is heated during drilling, and the asphalt with increased viscosity tends to adhere to the moving part of the cutter blade for diameter expansion. It is more likely that the blade will become irreversible and the drill bit will not come out.

In order to avoid such a situation, it is necessary to replace the entire drill bit consisting of straight hole machining cutter blade, diameter expanding cutter blade, operating rod, and cutter body with a new one in advance. Frequent replacement of the entire drill bit leads to an increase in construction costs. Therefore, there is a demand for a drill bit that can sustainably maintain good diameter expansion/restoration action of the diameter expansion edge and that can reduce the construction cost.

SUMMARY OF THE INVENTION The present invention is proposed in view of the above problems. It is an object of the present invention to provide a drill bit which can be maintained continuously and which can reduce construction costs, and a method for constructing post-installed anchors using the drill bit.

The drill bit of the present invention has a shank sleeve in which the rear portion of the shaft is inserted into and fixed to a generally bottomed cylindrical sleeve portion provided on the tip side of the shank portion, and guide screws are attached to screw holes in the front portion. , a substantially cylindrical intermediate sleeve provided on the tip side of the shank sleeve and having an axially extending long hole-shaped stroke guide formed on the peripheral wall at a position facing the rear portion, and an expanded bottom sleeve provided on the tip portion. a bottom-enlarging blade fixedly mounted in the bottom -enlarging sleeve; a sleeve joint screwed to each of the intermediate sleeve and the bottom-enlarging sleeve; and a rear end surface of the sleeve joint and a front end surface of the sleeve portion. and a compression coil spring embedded in the intermediate sleeve so as to be positioned at the bottom sleeve, and the enlarged bottom sleeve is formed with openings for opening and closing the enlarged diameter blade at positions facing the peripheral wall, and the enlarged bottom blade includes a pair of enlarged diameter blades. and a torsion coil spring that tiltably supports the pair of diameter-enlarging blades at their distal ends and urges them to close. An engagement receiving portion is formed to be engaged, and when the tip of the shaft presses the inner rear end of the bottom-enlarging blade, the diameter-enlarging blade can be tilted and expanded , and the stroke guide is provided. The guide screw, which is provided so as to be hooked, moves along the stroke guide as the shank sleeve and the shaft are pushed toward the enlarged bottom sleeve . Further, the drill bit of the present invention is characterized in that flat portions for fitting a tool are provided at opposing positions of the base of the sleeve joint.
According to this, the bottom-enlarging blade is composed of a pair of diameter-enlarging blades and a torsion coil spring that supports the pair of diameter-expanding blades on the tip end side so as to be tiltable and urges them to close. To detachably engage an arm part of a torsion coil spring in an engaging accommodating part, so that the enlarged bottom blade can be easily disassembled and cleaned without a tool if necessary, and can be easily reconstructed after cleaning. can be done. Therefore, it is possible to frequently clean the bottom expanding blade, and it is possible to prevent in advance from hindering the operation of the bottom expanding blade by chips of concrete and asphalt, asphalt with increased viscosity, etc. Restoration operation can be maintained continuously. In addition, frequent replacement of the entire drill bit is not required, and the enlarging blade can be simply cleaned, thus reducing construction costs.

In the drill bit of the present invention, a protective portion of the torsion coil spring is provided at the tip of the expanded bottom blade, and the protective portion is fitted into the fitting groove of the expanded bottom sleeve so that the expanded bottom blade is stationary. Characterized by
According to this, by protecting the torsion coil spring with the protective portion, the required operation of the torsion coil spring can be reliably obtained, and damage to the torsion coil spring can be prevented. Further, by fitting the protective portion into the fitting groove of the bottom-enlarged sleeve and fixing the bottom-enlarged blade, the bottom-enlarged blade can be stably fixed in the bottom-enlarged sleeve.

The post-installed anchor installation method of the present invention is a method of installing a post-installed anchor using the drill bit of the present invention as a drill bit for forming an enlarged diameter hole, wherein the drill bit for forming a straight hole is used to drill a hole in an existing structure. a first step of forming, inserting the drill bit for forming the enlarged diameter hole into the drilling until the tip of the drill bit for forming the enlarged diameter hole substantially abuts the bottom of the drilling, and expanding the diameter-enlarging blade a second step of forming a tapered enlarged diameter hole portion in the vicinity of the bottom portion of the drilled hole by diametrically protruding outward from the diameter enlarged blade entry/exit window; It is characterized by comprising a third step of driving the anchor in such a manner.
According to this, it is possible to construct the post-installed anchor while preventing or maximally suppressing a situation in which the expanded bottom blade cannot be restored and the drill bit cannot be removed, and the overall efficiency of the post-installed anchor construction work is improved. be able to. Further, by using the drill bit of the present invention as a drill bit for forming an enlarged diameter hole portion and separately using a drill bit for forming a straight hole for forming a straight hole, the structure of the drill bit of the present invention is simple and low cost. The drill bit of the present invention can be made to have a more compact structure, reduce the usage rate in the overall drilling operation, and reduce the load applied to the drill bit in the drilling operation, thereby prolonging the product life. Furthermore, by reducing the usage rate in the overall drilling operation, the possibility of chip clogging can be further reduced.

ADVANTAGE OF THE INVENTION According to the present invention, a drill bit capable of forming a tapered enlarged diameter hole portion near the bottom of a drilled hole formed in an existing structure can sustainably maintain good diameter expanding/restoring operation of the diameter expanding blade. It is possible to reduce the construction cost.

(a) is a front view of the drill bit of embodiment by this invention, (b) is the longitudinal cross-sectional view, (c) is the longitudinal cross-sectional view in the expanded state of the expanded-bottom blade. The front view of the shank sleeve in the drill bit of embodiment. The front view of the intermediate sleeve in the drill bit of embodiment. (a) is a vertical cross-sectional view of a sleeve joint in the drill bit of the embodiment, and (b) is a vertical cross-sectional view of the sleeve joint perpendicular to the cross-sectional plane of FIG. The front view of the shaft in the drill bit of embodiment. (a) is a front view of an expanded-bottom sleeve in the drill bit of the embodiment, (b) is its plan view, and (c) is its longitudinal sectional view. (a) is a plan view of the expanded bottom blade in the drill bit of the embodiment, (b) is its left side view, (c) is its front view, and (d) is a torsion coil spring attached from the expanded bottom blade of FIG. A front view of the removed state, (e) is a view taken along line AA of (e), and (f) is an exploded view of the expanded bottom blade of (a). (a), (b) is partial enlarged explanatory drawing explaining the diameter-expanding operation of the drill bit of embodiment. (a) is a perspective view of a first example anchor driven into a hole formed by the drill bit of the embodiment, (b) is a perspective view of an expansion sleeve of the first example anchor, and (c) is the first The front view of the anchor of an example, (d) is a longitudinal cross-sectional view of the anchor of a 1st example, (e) is a longitudinal cross-sectional view of the anchor of the 1st example in which the mounting bolt was screwed together and expanded. (a) to (g) are explanatory diagrams for explaining the procedure for constructing the anchor of the first example using the drill bit of the embodiment. (a) to (g) are explanatory diagrams for explaining the procedure for constructing the anchor of the second example using the drill bit of the embodiment. The perspective view which shows the example which installed the erection structure using the anchor of a 1st example.

[Construction method of drill bit and post-installed anchor according to the embodiment]
As shown in FIGS. 1 to 8, a drill bit 1 according to an embodiment of the present invention includes a shank sleeve 2, an intermediate sleeve 3 provided on the distal end side of the shank sleeve 2, and a compression coil spring embedded in the intermediate sleeve 3. 4, a sleeve joint 5 provided on the tip side of the intermediate sleeve 3, an enlarged bottom sleeve 6 provided at the tip of the drill bit 1, an enlarged bottom blade 7 fixedly embedded in the enlarged bottom sleeve 6, and a shank sleeve 2. It has a substantially cylindrical rod-shaped shaft 8 extending from the sleeve 6 to the enlarged bottom sleeve 6 .

As shown in FIG. 2, the shank sleeve 2 has a shank portion 21 to be attached to a hammer drill or the like, and a substantially bottomed cylindrical sleeve portion 22 is provided on the tip side of the shank portion 21 . A step surface 23 protruding outward is formed near the rear portion of the sleeve portion 22 . The rear portion of the shaft 8 is fitted into the sleeve portion 22 , the pin hole 24 of the sleeve portion 22 and the pin hole 81 of the shaft 8 are communicated with a pin 25 such as a spring pin, and the shaft 8 is fitted into the sleeve portion 22 . pinned together. Further, screw holes 26 are formed in the front portion of the shank sleeve 2 at opposing positions.

The intermediate sleeve 3, as shown in FIG. 3, is a substantially cylindrical member having a female thread 31 formed on the inner peripheral surface of the distal end thereof, and an axially extending long sleeve at a position opposite to the rear portion. A hole-shaped stroke guide 32 is formed in the peripheral wall. A male thread 51 on the rear side of the sleeve joint 5 is screwed into the female thread 31 , and a sleeve portion 22 of the shank sleeve 2 is inserted in the rear side of the intermediate sleeve 3 . A compression coil spring 4 is embedded in the intermediate sleeve 2 so as to be positioned between the intermediate sleeve 2 and the front end surface 221 . When the shank sleeve 2 is not pushed into the intermediate sleeve 3 and no force is applied, both ends of the compression coil spring 4 are in a state of being substantially in contact with or close to the rear end face 52 of the sleeve joint 5 and the front end face 221 of the sleeve portion 22, respectively. It's becoming

A shaft 8 fixed to the shank sleeve 2 is embedded in the intermediate sleeve 3 so as to pass through the inside of the compression coil spring 4 . A guide screw 33 is attached to the screw hole 26 of the sleeve portion 22 inserted into the intermediate sleeve 3, and the guide screw 33 is provided so as to protrude slightly outside the stroke guide 32 or be hooked on the stroke guide 32. . Due to the configuration in which the guide screw 33 moves along the stroke guide 32, the intermediate sleeve 3 is rendered non-rotatable with respect to the shank sleeve 2 and the shaft 8, and the rotational force of the shank sleeve 2 can be transmitted to the expanded bottom sleeve 6. At the same time, the shank sleeve 2 and the shaft 8 can be pushed into the expanded bottom sleeve 6 side by smooth movement along the stroke guide 32 .

The distance S by which the shank sleeve 2 and the shaft 8 can be pushed toward the enlarged bottom sleeve 6 is such that the front end surface 221 of the sleeve portion 22 is substantially in contact with or close to the compression coil spring 4 without compressive force being applied thereto. is the distance between the stepped surface 23 and the rear end surface 34 of the intermediate sleeve 3 in the state in which the shank sleeve 2 and the shaft 8 are pushed in by a distance S to bring the stepped surface 23 and the rear end surface 34 into contact with each other, which will be described later. The expanded bottom blade 7 is expanded to the maximum diameter (see FIG. 1).

As shown in FIG. 4, the sleeve joint 5 has a male thread 54 on the front side of the base 53 in addition to the male thread 51 on the rear side. screwed into the internal thread 61. That is, the intermediate sleeve 3 and the enlarged-bottom sleeve 6 are screwed to the sleeve joint 5, respectively, so that the intermediate sleeve 3 and the enlarged-bottom sleeve 6 are fixed in a mutually non-rotatable state when the drill bit 1 rotates. A plane portion 55 is provided at a position facing the base portion 53 of the sleeve joint 5 to fit a tool such as a wrench. A shaft 8 is also inserted into the sleeve joint 5 and is provided so as to reach the inside of the expanded bottom sleeve 6 .

As shown in FIG. 6, the expanded bottom sleeve 6 has a substantially bottomed cylindrical shape with a substantially conical distal end portion 62 formed therein, and the internal peripheral surface of the rear portion thereof has a female thread into which the male thread 54 of the sleeve joint 5 is screwed. 61 are formed. A fitting groove 63 into which the bottom-enlarged blade 7 is fitted is formed inside the tip portion 62 of the bottom-enlarged sleeve 6, and a diameter-enlarged blade entry/exit window 65 is provided at a position opposite to the fitting groove 63 on the peripheral wall 64 in the extending direction. 65 are formed.

As shown in FIG. 7, the expanded bottom blade 7 is composed of a pair of enlarged diameter blades 71 and a torsion coil spring 72 that supports the pair of enlarged diameter blades 71 and 71 so that they can be tilted on the tip end side and urges them to close. It is The enlarged diameter blade 71 has a blade material 711 such as a cemented carbide tip on the outside, and a rear end surface 712 is an inclined surface that inclines in the tip direction toward the inside. At the inner side of the rear end surface 712, an inclined groove 713 is inclined inward toward the front end at a steeper angle than the rear end surface 712 so that the stepped or gradually tapered front end portion 82 of the shaft 8 can easily enter. is formed. When the inner side surfaces 714, 714 of the pair of diameter-enlarging blades 71, 71 are aligned, the rear end surfaces 712, 712 form a valley-shaped recess toward the tip side, and the inclined grooves 713, 713 form a substantially conical hole. formed.

A substantially arc-shaped protective portion 715 is formed at the tip of the diameter-enlarged blade 7 corresponding to the tip of the bottom-enlarged blade 7, and a torsion coil spring 72 is wound between the protective portions 715, 715 of the pair of diameter-enlarged blades 71, 71. The portion 721 is accommodated, and the torsion coil spring 72 is protected by the protective portions 715 and 715 . The enlarged diameter blade 71 is provided with an engagement accommodation groove 716 corresponding to an engagement accommodation portion from the tip side, and the engagement accommodation groove 716 is aligned with the shape in which the arm portion 722 of the torsion coil spring 72 extends. formed on the front and back of the The arm portion 722 of the torsion coil spring 72 is detachably engaged in the engagement receiving groove 716, and the expanded bottom blade 7, which is composed of a pair of enlarged diameter blades 71 and 71 and the torsion coil spring 72, is inserted through the torsion coil spring 72. are integrated. In the example of FIG. 7, a pair of enlarged diameter blades 71 are urged inward from the front side and the back side by arm portions 722 accommodated in engagement accommodation grooves 716 and 716 on the front side and the back side. Thus, the expanded bottom blade 7 is integrated.

As shown in FIG. 7(f), the expanded bottom blade 7 can be easily installed by removing the arm portion 722 and the winding portion 721 of the torsion coil spring 72 from the engagement receiving groove 716 and the receiving portion between the protective portions 715 and 715, respectively. can be decomposed into The engagement receiving portion with which the portion near the tip of the arm portion 722 is engaged can be an engagement receiving hole formed in the enlarged diameter blade 71 instead of the engaging receiving groove 716. is. Further, the expanding-bottom blade 7 is fixed in the expanding-bottom sleeve 6 by fitting the protective portions 715 and 715 into the fitting grooves 63 of the expanding-bottom sleeve 6 .

When using the drill bit 1 of the present embodiment, as shown in FIG. 8, the drill bit 1 is inserted into the hole 91 until it substantially abuts the bottom of the hole 91 formed with the hole diameter D1, and the compression coil spring 4 is compressed, the shank sleeve 2 and the shaft 8 are pushed toward the tip side (see the thick arrow in FIG. 8(a)), and the tip of the shaft 8 presses the inner rear end of the expanded bottom blade 7. In other words, By pressing the inclined groove 713 and the rear end surface 712 with the tip of the shaft 8, the diameter-enlarging blades 71 are tilted against the closing bias of the torsion coil spring 72 to expand the diameter (see FIG. 8(b)). (see bold arrows). The diameter-expanded diameter-enlarged blades 71, 71 protrude outward from the diameter-expanded blade entry/exit windows 65, 65, respectively, and a blade member 711 such as a carbide tip also protrudes outward. Then, a rotational force is applied to the drill bit 1 while the diameter-enlarged blades 71 are expanded, and a tapered enlarged diameter hole portion 92 having a diameter D2 is formed in the vicinity of the bottom of the hole 91 .

When the formation of the tapered enlarged diameter hole portion 92 is completed, the pushing force of the shank sleeve 2 and the shaft 8 toward the distal end side is released, and the shank sleeve 2 and the shaft 8 are urged by the compression coil spring 4 to perform the drill. Move behind bit 1 and restore. Along with this, the pressure from the tip of the shaft 8 to the expanded bottom blade 7 is also released, and the expanded bottom blade 7 is restored to the closed state shown in FIG. It is accommodated in the bottom-enlarged sleeve 6 by entering inside the diameter-enlarged blade entry/exit windows 65 . Then, the drill bit 1 with the enlarged bottom blade 7 in the closed state is pulled out from the drill bit 91 in which the enlarged diameter hole portion 92 is formed.

The drill bit 1 of this embodiment can be used for installation and construction of various post-installed anchors. It is possible. The first example anchor 100 comprises a generally cylindrical sleeve 110 , an expansion sleeve 120 and a stepped nut 130 . The distal end of the sleeve 110 is formed with a tapered surface 111 that slopes inward toward the distal end, and the embedding depth of the anchor 100 and the drilling depth of the hole 303 into which the anchor 100 is inserted are correct at the rear portion. A position confirmation unit 112 is provided for confirming whether or not it is in position. The position confirming portion 112 of this example is circumferentially provided in a knurled shape at a predetermined position in the length direction of the sleeve 110 .

The expansion sleeve 120 has a plurality of expansion pieces 123 erected on an annular base 121 via a thin hinge portion 122. One expansion piece 123, a thin hinge portion 122, and another expansion piece adjacent thereto. A slit 124 is formed between the piece 123 and the thin hinge portion 122 . The stepped nut 130 is formed of a base portion 131 and a bottom portion 132 that annularly protrudes outward from the outer peripheral surface of the base portion 131. A female thread 133 is formed to screw a mounting bolt 140 so that the base portion 131 and the bottom portion 132 communicate with each other. ing.

In the anchor 100, the expansion piece 123 of the expansion sleeve 120 is arranged so as to contact the tip of the sleeve 110, the base portion 131 of the stepped nut 130 is inserted into the expansion sleeve 120, and the bottom portion 132 of the stepped nut 130 is inserted into the expansion sleeve 120. is arranged to abut on the base 121 of the . The distal ends of the mounting bolts 140 inserted into the sleeve 110 and the expansion sleeve 120 are screwed into the female thread 133 of the stepped nut 130 to integrate them.

When constructing the anchor 100 of the first example, for example, a hole 303 is formed in an existing structure 302 such as asphalt or concrete with a drill bit 301 for forming a straight hole, and the inside of the hole 303 is cleaned with a cleaning tool 304 (Fig. 10(a), (b)). After that, using the drill bit 1 as a drill bit for forming the enlarged diameter hole portion, the drill bit 1 is inserted into the bore 303 until the tip of the drill bit 1 substantially abuts the bottom 305 of the bore 303, and the enlarged diameter blades 71 and 71 are inserted. The diameter is increased to form a tapered enlarged diameter hole portion 306 in the vicinity of the bottom portion of the drilled hole 303 (see FIG. 10(c)). After the enlarged diameter hole portion 306 is formed, the inside of the perforated hole 303 is cleaned again with the cleaning tool 304 (see FIG. 10(d)).

After that, the anchor 100 integrated with the mounting bolt 140 with the expansion piece 123 in a non-expanded state is inserted into the hole 303 from the stepped nut 130 side, and the position confirmation part 112 is positioned on the surface of the existing structure 302 and the anchor 100 is installed. Make sure that the embedding depth of 100 or the drilling depth of drilling 303 is correct (see FIG. 10(e)). Then, the open end surface 308 of a substantially bottomed cylindrical driving tool 307 is brought into contact with the rear end surface 113 of the sleeve 110 , and the rear end of the driving tool 307 is struck with a hammer 309 . By this blow, the tapered surface 111 of the sleeve 110 enters inside the plurality of expansion pieces 123, the expansion pieces 123 are expanded, and the anchor 100 is driven. A plurality of expanded expansion pieces 123 form a locking portion of the anchor 100 and are engaged with the enlarged diameter hole portion 306 (see FIG. 10(f)).

After that, the mounting plate 310 of the required structure to be attached by the anchor 100 is arranged so as to be inserted into the mounting bolt 140 protruding from the existing structure 302, and the washer 141 is fitted onto the mounting bolt 140 from the outside of the mounting plate 310. Furthermore, the required structure is attached to the existing structure 302 by screwing the nut 142 onto the mounting bolt 140 from the outside (see FIG. 10(g)).

Further, the drill bit 1 of this embodiment can also be used for construction of the anchor 200 of the second example, which is a resin injection type anchor shown in FIG. When constructing the anchor 200 of the second example, as shown in FIGS. 11A to 11D, the construction process corresponding to FIGS. Carry out the construction process. After that, the resin capsule 200a is inserted into the hole 303 (see FIG. 11(e)), and the mounting bolt 210 with a sharp tip is inserted into the hole 303 to break the resin capsule 200a. The resin flowing out of the resin capsule 200a hardens after a predetermined time so as to embed the mounting bolt 210, thereby forming the anchor 200 of the second example. A locking portion 201, which is a part of the anchor 200, which is a resin injection type anchor, is engaged with an enlarged diameter hole portion 306 (see FIG. 11(f)).

After that, as in the case of the anchor 100 of the first example, the mounting plate 310 of the desired structure to be attached by the anchor 100 is arranged so as to be inserted into the mounting bolt 210 protruding from the existing structure 302, and the mounting plate 310 is The required structure is attached to the existing structure 302 by inserting the washer 211 onto the mounting bolt 210 from the outside and further screwing the nut 212 onto the mounting bolt 210 from the outside (see FIG. 11(g)). .

According to this embodiment, the expanded bottom blade 7 of the drill bit 1 is a pair of enlarged diameter blades 71, and the pair of enlarged diameter blades 71, 71 are tiltably supported on the distal end side to bias them closed. 72, and the arm portion 722 of the torsion coil spring 72 is detachably engaged with the engagement receiving groove 716 from the tip side of each diameter-enlarging blade 71, so that the bottom-enlarging blade 7 can be changed as needed. It can be easily disassembled and cleaned without tools, and easily reassembled after cleaning. Therefore, it is possible to diligently clean the bottom expanding blade 7, prevent in advance from hindering the operation of the bottom expanding blade 7 by chips of concrete or asphalt, asphalt with increased viscosity, etc., and improve the diameter expanding blade 71. The expansion/restoration action can be maintained continuously. In addition, frequent replacement of the entire drill bit is not required, and the enlarging blade 7 can be simply cleaned, thus reducing construction costs.

Moreover, by protecting the torsion coil spring 72 with the protective portions 715, 715, the required operation of the torsion coil spring 72 can be reliably obtained, and damage to the torsion coil spring 72 can be prevented. In addition, by fitting the protective portions 715 in the fitting groove 63 of the bottom-enlarged sleeve 6 and fixing the bottom-enlarged blade 7 , the bottom-enlarged blade 7 can be stably fixed in the bottom-enlarged sleeve 6 .

In addition, according to the post-installed anchor construction method using the drill bit 1 as a drill bit for forming an enlarged diameter hole, it is possible to prevent or minimize the situation in which the expanded bottom blade 7 cannot be restored and the drill bit 1 cannot be pulled out. Post-installed anchors such as the anchors 100 and 200 can be constructed, and the efficiency of the overall post-installed anchor construction work can be improved. Further, by using the drill bit 1 as a drill bit for forming an enlarged hole portion and separately using a drill bit 301 for forming a straight hole for forming a straight hole, the structure of the drill bit of the present invention can be simplified and at a low cost. The drill bit of the present invention can be structured and used in a reduced overall drilling operation, reducing the drilling load on the drill bit of the present invention and prolonging the product life. Furthermore, by reducing the usage rate in the overall drilling operation, the possibility of chip clogging can be further reduced.

[Scope of invention disclosed in this specification]
In addition to each invention and embodiment listed as an invention, the invention disclosed in this specification is specified by changing these partial contents to other contents disclosed in this specification within the applicable range, Alternatively, what is specified by adding other contents disclosed in this specification to these contents, or what is specified by deleting these partial contents to the extent that partial effects can be obtained and making them a broader concept contain. The invention disclosed in this specification also includes the following modifications and additional contents.

The drill bit 1 of the above embodiment has a structure including a shank sleeve 2, an intermediate sleeve 3, a compression coil spring 4, a sleeve joint 5, and a shaft 8. Any suitable structure is included as long as it is formed with the structure of and performs a predetermined operation.

In addition, the structure that is attached to the existing structure using the post-installed anchor constructed by the method of constructing the post-installed anchor of the present invention is appropriate. For example, as shown in FIG. It is possible to drive an anchor 100 of one example, attach a wire rope type protective fence 403 via a mounting plate 402, and install it. In addition, when installing post-installed anchors only on fragile base materials such as asphalt, the drilling diameter D2 of the tapered enlarged diameter hole is 1.5 times or more the drilling diameter D1 of the straight drilling. However, if a structure is adopted in which the locking portion of the anchor is locked over substantially the entire drilling diameter D2 of the enlarged diameter hole portion, the necessary strength can be ensured, which is favorable.

INDUSTRIAL APPLICABILITY The present invention can be used, for example, when forming holes for installing post-installed anchors in existing structures such as roads.

DESCRIPTION OF SYMBOLS 1... Drill bit 2... Shank sleeve 21... Shank part 22... Sleeve part 221... Front end surface 23... Step surface 24... Pin hole 25... Pin 26... Screw hole 3... Intermediate sleeve 31... Female screw 32... Stroke guide 33... Guide screw 34 Rear end surface 4 Compression coil spring 5 Sleeve joint 51 Male screw 52 Rear end surface 53 Base 54 Male screw 55 Plane portion 6 Enlarged bottom sleeve 61 Female screw 62 Tip 63 Fitting groove 64 Peripheral wall 65 Expanded diameter blade entry/exit window 7 Expanded bottom blade 71 Expanded diameter blade 711 Blade material 712 Rear end surface 713 Inclined groove 714 Inner surface 715 Protection part 716 Engagement accommodation groove 72 Torsion coil spring 721 Winding Part 722... Arm part 8... Shaft 81... Pin hole 82... Tip part 91... Drilling hole 92... Expanded diameter hole part 100... Anchor 110... Sleeve 111... Tapered surface 112... Position confirmation part 113... Rear end surface 120... Expansion sleeve 121... Base 122 Thin hinge 123 Extension piece 124 Slit 130 Stepped nut 131 Base 132 Bottom 133 Female screw 140 Mounting bolt 141 Washer 142 Nut 200 Anchor 201 Locking part 200a Resin capsule 210 ... Mounting bolt 211 ... Washer 212 ... Nut 301 ... Drill bit for forming a straight hole 302 ... Existing structure 303 ... Drilling 304 ... Cleaning tool 305 ... Bottom part 306 ... Expanded hole part 307 ... Driving tool 308 ... Tip surface 309 ... Hammer 310: Mounting plate 401: Asphalt road pavement 402: Mounting plate 403: Wire rope protection fence S: Distance that can be pushed into the shank sleeve and the expanded bottom sleeve side of the shaft D1: Drilling diameter of the hole D2: Diameter of the enlarged hole hole diameter

Claims (3)

a shank sleeve in which the rear portion of the shaft is fitted and fixed in a substantially bottomed cylindrical sleeve portion provided on the tip side of the shank portion, and a guide screw is attached to a screw hole in the front portion;
a substantially cylindrical intermediate sleeve provided on the distal end side of the shank sleeve and having a peripheral wall formed with an elongated hole-shaped stroke guide extending in the axial direction at opposing positions toward the rear;
an enlarged bottom sleeve provided at the tip;
A bottom-expansion blade fixedly mounted in the bottom-expansion sleeve When,
a sleeve joint screwed to each of the intermediate sleeve and the expanded bottom sleeve;
a compression coil spring embedded in the intermediate sleeve so as to be positioned between the rear end surface of the sleeve joint and the front end surface of the sleeve portion,
The expanding bottom sleeve is formed with a diameter expanding blade entrance window at a position facing the peripheral wall,
The bottom expanding blade is composed of a pair of diameter expanding blades and a torsion coil spring that supports the pair of diameter expanding blades on the tip end side so as to be tiltable and urges them to close,
An engagement receiving portion is formed in which the arm portion of the torsion coil spring is detachably engaged from the tip end side of each of the diameter-expanding blades,
by the tip of the shaft By pressing the inner rear end of the bottom-enlarging blade, the diameter-enlarging blade is tilted so that the diameter can be expanded. with
The guide screw provided so as to be hooked on the stroke guide moves along the stroke guide as the shank sleeve and the shaft are pushed toward the enlarged bottom sleeve. A drill bit characterized by: A flat portion for fitting a tool is provided at opposing positions of the base of the sleeve joint. The drill bit according to claim 1, characterized by: A method for constructing a post-installed anchor using the drill bit according to claim 1 or 2 as a drill bit for forming an enlarged diameter hole, comprising:
A first step of forming a hole in an existing structure with a drill bit for forming a straight hole;
The drill bit for forming the enlarged diameter hole is inserted into the bore until the tip of the drill bit for forming the enlarged diameter hole substantially abuts the bottom of the bore, and the diameter of the enlarged diameter edge is expanded to increase the diameter of the enlarged diameter edge. a second step of forming a tapered enlarged diameter hole portion protruding outward from the access window and near the bottom portion of the perforation;
A method of constructing a post-installed anchor, characterized by comprising a third step of driving the anchor so that the locking portion of the anchor is engaged with the enlarged diameter hole portion.

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