JPH0114846B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for expanding the diameter of a hole drilled in concrete.

[Conventional technology and its problems]

Recently, when attaching anchor bolts for attaching equipment to concrete structures, or when adding reinforcing bars to concrete walls, drilling machines are used to drill holes of appropriate depth into concrete walls. The method used is to drill a hole, insert an anchor bolt or the end of a reinforcing bar into the hole, and fix it in the hole with adhesive.

However, even with this construction method, the anchor bolts or braces fixed to the concrete wall are cylindrical in shape with a substantially uniform inner diameter, so the anchor bolts or braces are fixed to the concrete wall. If vibration is applied for a long period of time, the bond between the adhesive and the surface of the hole will peel off.
There was a problem in that the anchor bolts or braces tended to come off along with the adhesive attached to them.

To solve this problem, Japanese Patent Publication No. 54-27163 describes how to use the following drilling tool to drill a hole in the inner part of a hole previously drilled in a concrete wall. It has been proposed to form a hole with a diameter larger than the diameter of the mouth edge of the hole.

That is, a pair of through holes are formed in the tip of a cylindrical drill bit in a direction transverse to the axis of the drill bit, and a cutting blade is slidably disposed in each of the through holes. The pair of cutting blades are supported by the pair of through holes so as to be freely retractable outside the drill bit, and a cutting blade guide rod is provided with a tapered slit for pushing out the pair of cutting blades from behind. A drilling tool is inserted into the tip of the hole of a drill bit. When this drilling tool is attached to a hammer drill and the hammer drill is rotated and operated by impact in a hole previously drilled in concrete, the drill bit is inserted into the tip of the hole. The cutting blade guide rod inserted into the tip moves within the hole of the drill bit, and by the action of the tapered slit of this guide rod, the pair of cutting blades move the drill bit into the through hole formed in the drill bit. A direction in which the diameter of the hole is expanded is disclosed, in which a pair of rotating cutting blades that are moved in a direction protruding from the cylindrical surface of the drill bit scrape off the hole wall.

However, this conventional technology is not suitable for use as a drilling tool as described above because the drill bit that makes up the tool has many parts and its structure is complex and delicate, resulting in high costs. However, there is also a problem in terms of strength.In particular, the cutting blade that makes up the above-mentioned drilling tool is not fixed to the body of the drill bit, and the direction of rotation that the cutting blade receives from the wall of the concrete hole The reaction force is also received by the surface of the hole drilled in the cylindrical wall of the cylindrical drill bit, which supports the drill bit in a retractable (slidable) manner. The reaction force that the blade receives from the wall of the concrete hole in the direction of the center of rotation is absorbed by the tapered slit of the guide rod that slides against the back of the cutting blade, which increases the amount by which the diameter can be expanded. If the amount of protrusion of the cutting blade is increased in order to increase the cutting edge, the thickness of the drill bit body becomes thinner, so the structure of the drill bit for concrete drilling, where the cutting blade is subject to severe loads, is sufficiently satisfactory in terms of strength. I couldn't say that.

[Means for solving problems]

Therefore, in order to solve this problem, the present invention uses a completely different method from the above-mentioned conventional technology to attach a hole to the inner part of the hole that has been previously drilled in the concrete wall. It is an object of the present invention to provide a method and apparatus for expanding a hole, which can form a hole with a diameter larger than the diameter of the hole.

That is, the gist of the present invention is to provide a drill bit with a longitudinal groove of an appropriate length extending from the tip of the drill bit in the axial direction of the drill bit and vertically dividing the front of the drill bit into two; A wedge hole is formed to push apart the bifurcated portion formed by the vertical groove, and the small diameter portion of the wedge is inserted into the tip of the wedge hole of this drill bit. By rotating and impacting the drill bit in a hole drilled in concrete using a hammer drill attached to the rear end of the drill bit, a wedge whose small diameter portion is located at the tip of the drill bit is created. The action of the wedge moving in the wedge hole gradually expands and deforms the bifurcated part of the drill bit body, causing the bifurcated part to expand and rotate. A hole drilled in concrete, characterized in that the hole wall is also scraped off with a pair of cutting blades formed near the tip of the portion at a position approximately symmetrical with the vertical groove. A hole is formed at the axial center of a drill bit body of an appropriate length made of spring steel, and is located at a position of an appropriate length l from the tip of the drill bit body. Forming a hole for a wedge, which has a stepped portion and has a larger inner diameter from the stepped portion to the rear end of the drill bit body than the inner diameter of the portion from the stepped portion to the tip of the drill bit body; , forming a vertical groove in the drill bit body, which is a vertical groove that divides the drill bit body into two along the axial direction from the tip thereof, and whose cutting depth L is larger than the length l. The base of the cutting blade is fixed to a position near the tip of the drill bit main body at a position approximately symmetrical about the longitudinal groove, so that the cutting edge of the cutting blade protrudes from the outer surface of the drill bit main body. drill bit and
The diameter of the tapered tip is smaller than the diameter of the small diameter portion of the wedge hole formed in the drill bit body, and the diameter of the largest diameter portion at the rear is smaller than the small diameter portion of the wedge hole formed in the drill bit body. a small diameter of the wedge hole formed in the drill bit body at the rear end of the wedge, which is larger than the diameter of the larger diameter portion of the wedge hole but smaller than the diameter of the large diameter portion of the wedge hole; a wedge formed by protruding a rod-shaped part, the length of which is smaller than the part of the small diameter part, and whose length is longer than the length l of the small diameter part; It is located in the hole expansion device.

〔Example〕

One embodiment of the apparatus according to the present invention for carrying out the method of the present invention will be described with reference to the drawings. A drill bit 1 for drilling concrete in this embodiment forms a tapered shank 3 at the base. a drill bit body 2 made of spring steel;
It is composed of a pair of cutting blades 4, 4 made of ultra-hard steel that are fixed (fixed by brazing in accordance with a conventional method) near the tip of the drill bit body.

The drill bit body 2 has a hole 5 bored in the center of the cylindrical drill bit body 2, which passes through the drill bit body 2 along its axis from the tip to the base. A step 6 is formed at a position of an appropriate length l from the tip 2a of the main body 2, and the inner diameter of the hole 5 is equal to the diameter a of the hole 5a at the rear end side of the step 6. , this step 6
The diameter b of the hole 5b is set to be larger than the diameter b of the hole 5b at the tip end side.

The drill bit main body 2 also has the stepped portion 6.
An oblong through hole 7 passing through the center of the drill bit body 2 in the transverse direction is formed at a position closer to the proximal end of the drill bit body 2 than the drill bit body 2, and the through hole 7 is reached from the tip 2a of the drill bit body 2. A vertically dividing groove 8 is formed between the drill bit body 2 and the drill bit body 2 in the axial direction thereof.

At the tip of the drill bit main body 2 configured as described above, a pair of cut grooves 9, 9 are formed, with the longitudinal groove 8 being placed at a position approximately symmetrical to the center. The blade 4 has its base end fitted into each cut groove 9 and fixed (fixed by brazing in a conventional manner), and the blade part 4a is inserted from the side surface of the drill bit main body 2 toward the upper side in FIG. It is projected towards.

Since the concrete drilling drill bit 1 of this embodiment has the above-mentioned configuration, it is attached to the shank adapter 10 (see Fig. 5) of a known concrete drilling hammer drill, and then the following steps are performed. When the wedge 11 (Fig. 4) or the wedge 111 and the pad 112 (Figs. 7 to 9) are used together, this drill bit can be drilled in the cylindrical hole 16 previously drilled in the concrete base material 15 with a known hammer drill. By elastically deforming the bifurcated portion of the hole 16, a portion of the hole wall 16a in the inner part of the hole 16 is scraped off with the cutting blade 4 according to the method of the present invention, and the diameter of this portion is adjusted to the diameter of the hole 16. The diameter d of the mouth edge can be made larger than the diameter d of the mouth edge.

First, the details will be explained from an example using only the wedge 11 (an embodiment of the device of the present invention).
1, as shown in FIG. 4, the diameter of the tapered tip 11c is smaller than the diameter b of the small diameter portion 5b of the hole 5 formed in the drill bit body 1, and the diameter of the rear thickest portion 11d. is formed in the drill bit body 1 at the rear end of the wedge portion 11a which is larger than the diameter b of the small diameter portion 5a of the hole 5 and smaller than the diameter a of the large diameter portion 5b of the hole 5. It has a shape in which a rod-shaped portion 11b integrally protrudes and is smaller than the diameter b of the small hole portion 5b of the hole 5 and has a length longer than the length l.

In order to use this wedge 11 in combination to enlarge the diameter d of the inner part of the hole 16 drilled in concrete, the drill bit 1 of the present invention is attached to the shank adapter 10 of a hammer drill (not shown). Insert the taper shank 3, attach it to the hammer drill, and then insert the tip 2a of this drill bit 1.
The tip of the wedge portion 11a of the wedge 11 is inserted into the hole 5b until the wedge 11 is fitted and fixed therein. Wedge 1
1 is a state in which the large-diameter portion of the wedge portion 11a is not inserted into the hole 5b, so the rod-shaped portion 11b of the wedge 11 is made to protrude largely from the tip 2a of the drill bit 1 without deforming the drill bit 1. Fixed. Drill bit 1 in this condition
is a hole 16 with a diameter d slightly larger than the distance w between the tips of the pair of cutting blades 4, 4 in this state.
If you make a hole in the concrete base material 15 in advance,
The wedge 11 can be inserted into the hole 16 until the end of the rod-shaped portion 11b collides with the hole bottom 16b (FIG. 5).

In the state shown in FIG. 5, when the main shaft (not shown) of the hammer drill to which the shank adapter 10 is attached is driven, the drill bit 1 moves forward while rotating and the wedge 11 hits the hole bottom 16b. , the wedge 11 colliding with the hole bottom 16b at that time is the large diameter portion 11 of the wedge portion 11a.
d enters the hole 5b of the drill bit 1, and elastically deforms the pair of parts 2b, 2b of the bifurcated drill bit body, which is vertically divided into two parts by the vertical groove 8, as shown in FIG. Push it to the left and right. In this way, when the drill bit 1 rotates with its tips being pushed wider as it approaches the hole bottom 16b, the hole 16 drilled in the concrete base material 15 will now have a gap w between its tips. A pair of cutting blades 4 that rotate while being gradually enlarged,
4, the hole wall surface 16a is scraped off so that the diameter D increases as it approaches the hole bottom 16b (FIG. 6).

As the drill bit 1 drills as described above, the small diameter portion 5 of the hole 5 of the drill bit 1
In case of b, the wedge 11 was pushing and expanding the bifurcated parts 2b, 2b of the drill bit main body 2.
Eventually, the wedge portion 11a becomes the small diameter portion 5b of the hole 5.
After passing through, the large diameter portion 5a of the hole 5 is reached. The wedge 11 has a wedge portion 11a that is connected to the drill bit 1.
When it comes out into the large diameter part 5a of the hole 5, the wedge part 11
The diameter of a is such that the diameter of the large diameter portion 11d is smaller than the diameter of the large diameter portion 5a of the hole 5 of the drill bit, and the diameter of the rod-shaped portion 11b is smaller than the diameter of the small diameter portion 1 of the hole 5 of the drill bit.
5b, so the drill bit body 2
At this time, the elastically deformed state is restored to the state before elastically deformed, and the wedge 11, which has been elastically deforming the drill bit 1, deforms at least the large diameter portion 11d of the wedge portion 11a into the drill bit 1.
is placed in the large-diameter portion 5a of the hole 5, and can move freely within the hole 5.

Therefore, the drill bit 1 for concrete drilling according to the diameter expanding device of the present invention, which has completed the drilling action in the hole diameter expanding direction, can be freely extracted from the hole 16, and the taper shank 3 The drill bit 1 of the embodiment has
By pulling it out from the hole 16 and then pulling it out from the shank holder 10, the wedge 11 can be recovered from the hole 5 of the drill bit 1 and reused. like,
If you want to make the length of the tipter hole 14 of the shank holder 10 slightly larger than the length of the wedge 11, even if the drill bit 1 is still attached to the shank holder 10, you can do the following to make the drill bit 14 from the tipter hole 14. The wedge 11 inside the hole 5a can be recovered. This is because when the drill bit 1 is pulled out from the hole 16 after completing the diameter expansion action,
When the drill bit 1 is turned upside down, the wedge 1, which can freely move the large diameter portion 5a of the hole 5 of the drill bit 1, can easily be moved to the position shown by the chain line in FIG. Because it can be done.

In addition, when the length of the rod-shaped portion 11b of this wedge 11 is selected to be an arbitrary length longer than l, the diameter of the hole wall surface 16a at an arbitrary depth position from the entrance of the hole 16 drilled in the concrete base material 15. By using two or more wedges 11 having different lengths of the rod-like portions 11b, the diameter D of the hole 16 can be enlarged at any two or more positions from the entrance of the hole 16. . (The bulge 1 on the hole wall shown by the chain line in Figure 6)
6d).

Further, the method for enlarging the diameter of a hole drilled in concrete according to the present invention uses the concrete drilling drill bit 1 of the above embodiment together with a wedge 111 and a pad 112 as shown in FIGS. You can also do this by doing this.

That is, in the wedge 111 shown in FIGS. 7 and 8, the diameter of the tapered tip 111c is smaller than the diameter b of the small diameter portion 5b of the hole 5 formed in the drill bit body 2, and the diameter of the thickest portion 111d at the rear is smaller than the diameter b of the small diameter portion 5b of the hole 5 formed in the drill bit body 2. It is a wedge whose diameter is larger than the diameter b of the small diameter portion 5b of the hole 5 and smaller than the diameter of the large diameter portion 5a of the hole 5, and the stopper 112 has a diameter approximately equal to the diameter of the drill bit body 2. At the center of one end surface of the cylinder 112a is a cylinder whose diameter is smaller than the small diameter portion 5b of the hole 5 of the drill bit body 2 and whose length is longer than the length l of the small diameter portion 5b of the hole 5 of the drill bit body 2. Although the pin 112b is integrally provided, when the wedge 111 and the stopper 112 are used together with the drill bit 1, like the wedge 11,
The tip of the wedge 111 is inserted into the hole 5b at the tip of the drill bit 1 until it is fitted and fixed, and the hole 1 previously drilled in the concrete base material 15 is inserted.
The pad 112 is inserted into the hole 16 with the pin 112b facing toward the entrance of the hole 16. In this state, when the drill bit 1 attached to the shank holder 10 of a hammer drill (not shown) is inserted into the hole 16, the wedge 111 attached to the tip of the drill bit 1 hits the pin 1 of the stopper 112.
12b, and the stopper 112 is pressed against the hole bottom 16b. Therefore, if the main shaft of the hammer drill is operated in this state,
As the drill bit 1 enters, the pad 112
At this time, the wedge 111, which has collided with the pin 112b and is prevented from advancing, is pushed relatively into the hole 5b, so at this time, the drill bit 1
As in the case where the wedge 11 is used in combination, the bifurcated parts 2b, 2b of the drill bit body divided into two by the vertical groove 8 are elastically deformed, and at this time the hole 16 in the concrete base material 15 is , cutting blade 4
The portion of the hole wall surface 16a that was hit by the hole wall surface 16a is scraped off so that its diameter D becomes larger (FIG. 10).

When such a wedge 111 and pad 112 are used together, the length of the wedge 111 is equal to the length of the wedge 11.
Even if the drill bit 1 is pulled out from the hole 16, the presence of the drill bit 1 can be utilized while the drill bit 1 is still attached to the shank holder 10, even if the drill bit 1 is pulled out from the hole 16. It can be recovered by

Note that the pin 112 can be any collection tool (for example, something like a stick that can hold the stick part).
It can be recovered with. Also, guess money 112
For example, if the length of the cylindrical portion 112a is arbitrarily selected, the hole 1 drilled in the concrete base material 15
The diameter of the hole wall surface 16a at any depth position from the entrance of the hole 16 can be expanded, and by using two or more pads 112 of different lengths, the diameter of the hole wall surface 16a can be expanded at any two or more positions from the entrance of the hole 16. The diameter of the holes 16 can be partially enlarged.

[Operation and effect of the invention]

The method and device for expanding the diameter of a hole drilled in concrete according to the present invention have been described above with reference to several embodiments. The drill bit for concrete drilling has a drill bit body made of spring steel, and the drill bit body is divided into two bifurcated parts by a vertical groove along the axial direction.
When a wedge is driven into the tip of the two-pronged part of this drill bit body, it is elastically deformed and the crotches of the two-pronged part can be pushed apart. Further, on the outer surface of the drill bit body which can be elastically deformed in this way, a pair of cutting blade parts are formed near the tip of the fork-shaped part at a position approximately symmetrical with the vertical groove. Therefore, when this drill bit is attached to the main shaft of a hammer drill and actuated by the main shaft of the hammer drill in a pre-drilled hole in the concrete base material, an impact movement along the axial direction of the main shaft is generated. Then, drive the wedge into the vertical groove from the tip of the fork-shaped part, push the fork-shaped part apart, and then push the cutting edge on the outer surface of the wedge against the hole wall surface. In addition to acting in the direction, due to the rotational movement of the main shaft,
By rotating the cutting blade, the hole wall surface can be cut so that the diameter D of the hole wall surface in the portion where the cutting blade acts is larger than the diameter d of the hole wall surface in other portions.

The drill bit constituting the device of the present invention is formed with a hole that passes through the drill bit along its axis, and the diameter of the hole differs from the large diameter portion at the stepped portion. The wedge is divided into a small-diameter portion, and the wedge is made to act on the drill bit only in the small-diameter portion, and in order to elastically deform the forked portion of the drill bit into an expanded state, the wedge is separated from one end of the drill bit. When the wedge is driven into the larger diameter part of the hole, the elastic deformation of the fork-shaped part is restored to its pre-deformed state, so it is difficult to prevent the wedge from being previously drilled into the concrete base material. This drill bit, which has finished cutting a predetermined amount of the wall surface of the hole, can be freely extracted from the hole.

As described above, a hole 1 whose hole wall has been partially cut by the method of the present invention using the apparatus of the present invention.
As shown in FIG. 11, a bulge 16d with a diameter D larger than the diameter d of the mouth edge of the hole is formed in the inner part of the hole 16.
Insert the anchor bolt or the end of the reinforcing bar 18 into the
When it is fixed with the adhesive 19 filled in the hole 16, the anchor bolt or the reinforcement will be tightly wrapped around the anchor bolt or the reinforcement 18 even if vibration is applied to it over a long period of time. The large diameter D portion of the adhesive 19 that has been bonded and solidified is attached to the hole wall surface 16a.
Since it is caught on the small diameter part of the hole 16, the adhesive surface between the hole wall surface 16a and the solidified adhesive 16a does not peel off, and is kept strongly fixed in the hole 16 forever.

[Brief explanation of drawings]

Fig. 1 is a front view showing an embodiment of a concrete drilling drill bit for implementing the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a sectional view taken along the - line in Fig. 1. , Fig. 4 is a front view showing an example of the wedge, Figs. 5 and 6 are longitudinal sectional front views showing an example of the state in which the drill bit is used, Fig. 7 is a front view showing another example of the wedge, and Fig. 8 is a front view showing an example of the wedge. The figure is a longitudinal sectional view of the same, Fig. 9 is a front view showing an example of the pad, Fig. 10 is a longitudinal sectional front view showing another example of how the drill bit is used, and Fig. 11 is an anchor bolt inserted and fixed. FIG. 1... Drill bit, 2... Drill bit body, 3... Taper shank, 4... Cutting blade, 4
a...Blade part, 5...Wedge hole, 5a...Large diameter part, 5b...Small diameter part, 6...Step part, 8...Vertical groove, 11...Wedge, 11a... Wedge section, 11b...
... Rod-shaped portion, 11c... Tapered tip, 11d...
large diameter part.

Claims (1)

[Scope of Claims] 1. A drill bit body has a vertical groove of an appropriate length extending from the tip of the drill bit along the axial direction of the drill bit, dividing the drill bit body into two in the vertical direction, and this vertical groove. A drill bit is provided with a wedge hole for pushing and expanding the forked portion formed by the drill bit, and the small diameter portion of the wedge is inserted into the tip of the wedge hole of the drill bit. By rotating and impacting a hammer drill attached to the rear end of the drill bit in a hole drilled in the concrete, a wedge whose small diameter part is located at the tip of the drill bit is created. The fork-shaped part of the drill bit body is gradually expanded and deformed by the action of the wedge moving in the hole for the wedge, and the tip of the fork-shaped part is expanded and rotated. A method for enlarging the diameter of a hole drilled in concrete, characterized by scraping off the hole wall with a pair of cutting blades formed in the vicinity at a position approximately symmetrical with the vertical groove. 2. A hole passing through the drill bit body along the axis of the drill bit body of an appropriate length made of spring steel, and having a stepped portion at a position of an appropriate length l from the tip of the drill bit body, A wedge hole is formed in the drill bit body, the inner diameter of the part from the step part to the rear end of the drill bit body being larger than the inner diameter of the part from the step part to the tip of the drill bit body. , a vertical groove that divides the drill bit body into two along the axial direction from the tip thereof, and whose cutting depth L is larger than the length l; The base of the cutting blade is fixed to a position near the tip of the drill bit with the longitudinal groove as the center of symmetry, and the cutting edge of the cutting blade is made to protrude from the outer surface of the drill bit body. The diameter of the tip part is smaller than the diameter of the small diameter part of the wedge hole formed in the drill bit body, and the diameter of the largest diameter part at the rear is smaller than the diameter of the small diameter part of the wedge hole formed in the drill bit body. a small diameter portion of the wedge hole formed in the drill bit body at the rear end of the wedge portion, which is larger than the diameter of the wedge hole but smaller than the large diameter portion of the wedge hole; A hole drilled in concrete, characterized in that the hole is formed of a wedge having a protruding bar-shaped portion, the length of which is smaller than the length l of the small-diameter portion. diameter expansion device.