JP2000141358A - Method for execution of anchor and cutting bit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form efficiently in operation a hole for fixing an anchor on an inner wall surface without generating a crack, which has a coarse surface to obtain a sufficient fixing strength to the anchor wherein a sticking area to an adhesive is large as in the case of perforation of a surface of an existing concrete with a vibration drill or a hammer drill. SOLUTION: In the executing method, an inserting hole 30 is formed wherein a helical recessed groove 9 by a carbide chip 8 is provided on an inner wall surface by inserting a cutting bit 6 wherein a plurality of the carbide chips 8 are projected along a helical locus on an outer peripheral surface of the almost same diameter as that of the inner wall surface of a pretreated hole 4 while it is rotating in the pretreated hole 4 after perforating the pretreated hole 4 for inserting an anchor member on an existing concrete with a diamond core bit 1. The anchor member 12 is fixed by sticking with an adhesive 11 filled in the inserting hole 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction method for attaching anchor members such as anchor bars and anchor bolts to a surface of existing concrete as a post-construction, and a cutting bit used in the construction method.

[0002]

2. Description of the Related Art Conventionally, as a means for attaching an anchor member to existing concrete as post-processing, first, a hole is drilled in the surface of concrete as a base material by a vibration drill or a hammer drill, and the like. Clean the inside, then insert an adhesive capsule into the hole, then insert an anchor member such as a bolt or a reinforcing bar into the hole to break the adhesive capsule, so that the outer periphery of the anchor member in the hole is A method is known in which the adhesive is filled and cured in this state until the adhesive is cured.
For example, it is disclosed in JP-A-6-306957.

[0003]

In the above anchoring method, as means for drilling holes in the surface of concrete,
Vibration drills and hammer drills with carbide tips have been widely used.However, drilling with these drills requires a relatively large amount of time for work, and because the fatigue of workers due to vibration is large. Work efficiency is poor, and there are problems such as generation of cracks which cause a reduction in supporting force in the base material concrete due to continuous vibration applied to the base material concrete.

[0004] As a means for solving the above problems in the case of drilling with a vibration drill or hammer drill with a carbide tip, drilling with a diamond core bit can be considered, but with a hole drilled with a conventional diamond core bit. Since the inner peripheral surface is smoother, the adhesive force of the adhesive to the inner wall surface of the hole is weaker than a rough hole on the inner peripheral surface drilled with a vibration drill or hammer drill with a carbide tip,
The draw-out load of the anchor member is less than half of the required maximum load and adhesion strength, and there is a problem that sufficient strength cannot be obtained.

[0005] On the other hand, as a method of anchoring, it is known to provide an expanded bottom below the drilled hole to increase the pull-out resistance of the anchor member. Even if it is adopted, the adhesive force between the inner wall surface of the hole and the adhesive will be improved in a very small part such as the expanded bottom, but the adhesiveness of the entire hole is not improved, There is a problem that the smoothness over the entire wall surface is still left, and sufficient adhesion strength cannot be obtained.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the conventional anchoring method, the present invention first drills a hole having a predetermined inner diameter with a diamond core bit on the surface of existing concrete. By rotating and pushing the cutting bit into this hole, drilling work can be performed efficiently without cracking, and adhesion to the inner wall surface of the hole is the same as that of drilling with a vibration drill or hammer drill. An object of the present invention is to provide an anchoring method capable of forming a rough surface capable of obtaining a sufficient adhesive strength by increasing the area, and a cutting bit therefor.

According to a first aspect of the present invention, as a specific means for this, a pretreatment hole for inserting an anchor member is formed in an existing concrete with a diamond core bit, and the diameter is substantially the same as the inner wall surface of the pretreatment hole. On the outer peripheral surface, a cutting bit in which a plurality of carbide tips are protruded along a spiral track is inserted while rotating into the pretreatment hole, and a spiral groove formed by the carbide tips is inserted into the inner wall surface. The insertion hole provided is formed, and then the adhesive is filled in the insertion hole and the anchor member is pushed in, and the anchor member is adhered and fixed in the insertion hole by solidification of the adhesive.

[0008] The invention of claim 2 is a construction of the cutting bit used in the anchoring method, wherein an outer peripheral surface having substantially the same diameter as an inner wall surface of a pretreatment hole for anchor member insertion drilled in existing concrete, A plurality of cemented carbide tips made of cemented carbide or diamond are protruded along the spiral orbit.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1a to FIG. 1f show steps of an anchor installation method according to an embodiment of the present invention, and FIG. A diamond core bit 1 provided with a diamond tip 2 at its tip
By rotating the diamond core bit 1, a pretreatment hole 4 having a predetermined inner diameter and a predetermined depth is formed in the existing concrete C.

After a pretreatment hole 4 having a predetermined inner diameter and depth is formed, as shown in FIG. 1B, the inside of the pretreatment hole 4 is cleaned by a vacuum means 5 to make the inside of the hole smooth. Then, the diamond core bit 1 is removed from the drilling machine 3, and the cutting bit 6 shown in FIG. 2 is attached to the drilling machine 3 via the adapter 7, and as shown in FIG. The cutting bit 6 is inserted into the pre-processing hole 4 while rotating, and a helical concave groove 9 is formed on the inner wall surface of the pre-processing hole 4 by the cemented carbide tip 8 provided on the surface of the cutting bit 6.

As shown in FIGS. 2 and 3, the cutting bit 6 is formed on the surface of a cylindrical, cylindrical or prismatic bit body 6a having an outer diameter substantially the same as or slightly smaller than that of the diamond core bit 1. A plurality of cemented carbide tips 8 project from the lower end of the main body 6a at intervals along a spiral orbit A having a predetermined angle.

The cemented carbide tip 8 is shown in FIGS.
5 or a conical protruding piece as shown in FIG. 5, protruding from the surface of the main body 6a at a pitch of about 3 to 10 mm on the surface of the main body 6a. Is preferable, and the material is JIS E
Although some kinds of cemented carbides are preferred, diamond chips, high speed steel or the like may be used.

Further, the main body 6a of the cemented carbide tip 8
As shown in FIGS. 4 and 6, the projecting length from the peripheral surface is such that the concave groove 9 having a depth of 1 to 3 mm is spirally formed on the inner wall surface of the pretreatment hole 4. It is preferable that the projection length is 1
mm shallower grooves have insufficient adhesion strength.
In the case of a deep groove having a depth of not less than mm, defects are easily generated in the opening of the hole 4 and the like.

As shown in FIG. 1C, after forming a helical groove 9 by the cemented carbide tip 8 of the cutting bit 6 on the inner wall surface of the hole 4, the cutting bit 6 is extracted from the hole 4 and FIG.
Then, the inside of the hole 4 is cleaned again and dried, thereby obtaining the insertion hole 30. Next, as shown in FIG.
In addition, the capsule 10 in which the adhesive 11 is sealed is inserted into the housing 10, and the capsule 10 is broken by pushing the anchor member 12 from above, and as shown in FIG. Waiting for curing, anchor member 12
Is fixed in the insertion hole 30 having the concave groove 9.

The following table compares the load of the anchor member coming out of the insertion hole in the embodiment of the present invention with the load of the conventional method as a comparative example.

[0016]

[Table 1]

Referring to Table 1, the first embodiment of the present invention relates to a case where a concave groove is formed on the inner wall surface of a hole formed by a diamond core bit by using a cutting bit provided with a hemispherical tip shown in FIG. Example 2 shows the value of the load of the anchor member coming out, and Example 2 shows the value of the load of the anchor member coming out of the anchor member when a concave groove is formed by the cutting bit provided with the conical tip shown in FIG. 5. Five JIS E type cemented carbide tips were protruded at a helical position at a pitch of 6 mm at a spiral position, and the depth of the groove on the inner wall surface of the hole was set to 3 mm.

The insertion hole provided with a concave groove on the inner wall surface has a diameter of 34 mm and a depth of 300 mm, and the anchor member is JIS SD345, the nominal sectional area is 506.7 m.
m ^2, the tensile strength of the lower limit 35 kgf / mm ² D25
A deformed steel bar was used, and the adhesive was made of a corrosion-resistant polyester resin as a main component and encapsulated in a capsule having an outer diameter of 28 mm and a length of 250 mm.

On the other hand, in Comparative Example 1, a capsule containing a conventionally used adhesive was inserted into a hole only drilled with a diamond core bit, and an anchor bar was pushed thereon to break the capsule. Comparative Example 2 shows the value of the escape load when the anchor member was attached by the adhesive filled into the hole.
This is the value of the load at which the anchor streaks come off when fixed by the same method as described above.

[0020]

According to the anchoring method of the present invention, the drilling of a hole and the formation of a rough surface on the inner wall surface of the hole are separated into separate steps, and a pretreatment hole is first drilled in existing concrete with a diamond core bit. Then, a spiral concave groove is formed on the inner wall surface of the pretreatment hole using a cutting bit in which a plurality of cemented carbide tips are protruded on the outer peripheral surface, so that the pretreatment hole having a predetermined depth is formed. Can be efficiently drilled first,
Since the pushing force of the cutting bit is sufficient to cut the groove with the cemented carbide tip on the inner wall surface of the pre-drilled hole, a spiral groove is formed by drilling the drill bit from the pre-drilled hole. Can be performed in a much shorter time and more efficiently and without giving the operator fatigue due to vibration, as compared with a conventional drilling step using a vibration drill or a hammer drill.

The cutting bit forming a spiral groove on the inner wall surface of the pretreatment hole is a cylinder or a cylinder having an outer diameter substantially the same as or slightly smaller than the diameter of a diamond core bit used for drilling the pretreatment hole. Alternatively, three to six cemented carbide tips are provided on the surface of a prismatic bit body with a spiral orbit A having a predetermined angle.
Can be provided at intervals along the line, so that it can be manufactured at a relatively low cost.

When a conventional hammer drill is used, cracks are generated in the base material concrete at a high rate. On the other hand, in the anchoring method of the present invention, a pretreatment hole having a predetermined depth is formed in the diamond core bit. Rotation, and the formation of a spiral groove on the inner wall surface of the hole is also performed by the rotation of the cutting bit, so that cracks do not occur in the base material concrete, and the problem of lowering the support force of the anchor member due to the cracks is reliably solved. Can be.

As shown in Table 1, Examples 1 and 2 of the present invention
In Comparative Example 2, the numerical value of the pull-out load of the anchor streaks hardly changed as compared with Comparative Example 2 in which a hole was drilled by a hammer drill, indicating that there was no inferiority in strength. On the other hand, when Examples 1 and 2 of the present invention are compared with Comparative Example 1 in which an anchor streak is fixed to a hole just drilled with a diamond core bit, in Examples 1 and 2, The number of cutting processes is increased by one, but since the concave area is provided on the inner wall surface of the hole, the bonding area between the inner wall surface of the hole and the adhesive fixing the anchor member is greatly increased, and the pull-out resistance is increased. The load shows a numerical value twice or more as compared with Comparative Example 1.

As described above, according to the anchor installation method and the cutting bit of the present invention, it is possible to expect a significant reduction in the time required for drilling concrete and a reduction in the degree of fatigue of workers, as well as the occurrence of cracks. Eliminate problems,
There is an advantage that an anchor installation method with sufficient adhesive strength can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a procedure of an anchor construction method according to the present invention.

FIG. 2 is a side view showing the configuration of a cutting bit used in the anchor installation method of the present invention.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a sectional view showing a shape of a pretreatment hole cut by the cutting bit of FIG. 2;

FIG. 5 is a side view showing another embodiment of the cutting bit.

FIG. 6 is a sectional view showing a shape of a pretreatment hole cut by the cutting bit of FIG. 5;

[Explanation of symbols]

 1: diamond core bit 2: diamond tip 3: drilling machine 4: pretreatment hole 5: vacuum means 6: cutting bit 6a: bit body 7: adapter 8: cemented carbide tip 9: concave groove 10: capsule 11: adhesive 12 : Anchor member 30: insertion hole

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tetsuya Mishima 1-39-16 Asahimachi, Nerima-ku, Tokyo Inside Maeda Ken R & D Co., Ltd. (72) Inventor Takayuki Ohara 1-chome, Asahicho, Nerima-ku, Tokyo 39-16 No. 16 Maeda Construction Engineering Co., Ltd. Technical Research Institute F term (reference) 2E125 AA01 AA76 AB13 AC14 AF01 AG10 AG13 AG23 BE10 CA81 CA86 3C069 AA04 BA09 BB02 BB04 CA10 DA01 EA05

Claims (2)

[Claims] After a pretreatment hole for anchor member insertion is formed in an existing concrete with a diamond core bit, a plurality of pretreatment holes are formed on an outer peripheral surface having substantially the same diameter as an inner wall surface of the pretreatment hole along a spiral track. A cutting bit protruding a carbide tip is inserted into the pre-treatment hole while rotating, to form an insertion hole provided with a spiral groove by the carbide tip on the inner wall surface, and then into the insertion hole. And an anchor member which is filled with an adhesive and the anchor member is pushed in, and the anchor member is fixed in the insertion hole by solidification of the adhesive. 2. A cemented carbide made of a plurality of cemented carbides or diamonds along a spiral track on an outer peripheral surface having substantially the same diameter as an inner wall surface of a pretreatment hole for inserting an anchor member formed in existing concrete. Cutting bit for the construction of anchors with protruding tips.