JPH01280176A - Drilling of concrete structure - Google Patents

Abstract

PURPOSE:To exactly and easily scoop out cores by a method in which expanded resin cores are supported on a bar holder set between formworks, ready-mixed concrete is placed into the formworks, and the cores are melted by a rotary frictional cylinder through a guider. CONSTITUTION:A bar holder 36 is set on a place where a through hole is to be formed between formworks 31 and 32 to support a round columnar polyethylene foam core 37 with a cut-away. Concrete is placed into the formworks 31 and 32 and hardened, and the formworks 31 and 32 and the holder 36 are removed, to form a core hold. The guider of a borer 11 is inserted into the core hole and the frictional cylinder of the borer 11 is turned by a drill 39 by pressing the tip of the frictional cylinder on the core 37 in such a way as to melt the portion touched by the cylinder of the core 37 in order to scoop out the core 37. The core 37 can thus be scooped out exactly and easily.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for drilling holes in concrete structures, which is used, for example, when forming through holes for installing piping in the walls of buildings. .

[Conventional technology]

Conventionally, when creating through holes in concrete buildings,
Fresh concrete was poured into a formwork to form the wall surface, and after the concrete had hardened, the through holes were formed by drilling or other processing.

[Problem to be solved by the invention]

However, hollowing out solidified concrete involves extremely difficult work. Therefore, in the above conventional method,
The problem was that the work required a long time and the construction cost was high.

Therefore, for example, before pouring fresh concrete into the formwork, a foamed resin core made of foamed polystyrene, foamed polyethylene, etc. is provided, and after the concrete poured into the formwork has solidified, the said core is removed. A possible method is to form a through hole by doing so.

Expanded polystyrene that can be used as the core has relatively high rigidity. Therefore, the ready-mixed concrete is not easily deformed when poured into the formwork, so that the distortion occurring in the formed through-holes can be kept relatively small. However, foamed polystyrene has poor mold releasability, making it difficult to remove the core after the concrete has hardened.

On the other hand, although foamed polyethylene has good mold releasability, it has low rigidity, so it is easily deformed by the external force applied when filling with fresh concrete and the shrinkage force of concrete that occurs when concrete hardens. Therefore, there is a possibility that the formed through-hole is likely to be distorted, and it also becomes difficult to remove the core.

Further, in order to remove the core embedded in the solidified concrete, a method of removing the core by dissolving the foamed resin with a solvent can be considered. However, depending on the material of the core, this method can reliably remove the core, but
Since it requires a large amount of solvent, the construction cost is high, and it has a strong pungent odor, making it difficult to work. Furthermore, since polyethylene is difficult to dissolve in solvents, this method cannot be used when a core made of foamed polyethylene is used, resulting in a lack of flexibility.

Furthermore, it is also conceivable to incinerate and remove the core after the concrete has solidified. However, since it is difficult to completely incinerate the core, there is a risk that the inner surface of the through hole may become darkened due to adhesion of carbonized resin. In this case, it is necessary to incinerate the core and then excavate it mechanically, resulting in high construction costs.

On the other hand, a method of hollowing out the core by rotating a cylindrical saw with saw teeth at the end using a drill or the like and pushing the saw teeth against the exposed end surface of the core while propelling it in the axial direction is also considered. However, since foamed resin is generally brittle, when it is cut with a saw or the like, a large amount of chips are generated and become stuck between the foamed resin and the saw. This increases the frictional force between the saw and the foamed resin, so as the depth of the hole increases, it often becomes impossible to rotate the saw against the frictional force between the saw and the foamed resin. Become. Therefore, deep through holes cannot be made with this method.

Therefore, conventionally, it has been difficult to form deep through holes with little distortion in concrete structures without requiring difficult work and at low construction costs.

[Means to solve the problem]

In order to solve the above-mentioned problems, the method for drilling holes in concrete structures according to the present invention spans a rod-shaped holder between formworks provided facing each other, and foams with a length extending between the formworks. After the resin core is supported through the holder,
A process of pouring fresh concrete between the forms and removing the form and the holder after the concrete has solidified, and inserting a rod-shaped guide member into the core hole formed after removing the holder, and While rotating the friction cylinders provided integrally and concentrically, the tip end face of the friction cylinder is pressed against the exposed end face of the core, and the core is heated by the frictional heat generated at the contact area between the friction cylinder and the core. The method is characterized by the step of hollowing out the core by propelling the friction cylinder in the axial direction while locally melting it.

[For production]

With the above configuration, a foamed resin core having a length extending between the molds is embedded in the ready-mixed concrete poured between the molds. Therefore, by removing the formwork after the concrete has hardened, the end face of the core is exposed.

Further, since the core is supported through the holder which is spanned between the molds, when the holder is removed, a straight core hole is formed inside the core.

Therefore, by inserting a rod-shaped guide member into the core hole and rotating the friction cylinder provided integrally and concentrically with this guide member, the friction cylinder is rotated around an axis concentric with the core hole. can be done.

On the other hand, when the tip end surface of the friction cylinder is pressed against the exposed end surface of the core while rotating the friction cylinder, the core is locally melted by the frictional heat generated at the contact area between the friction cylinder and the core. When the core melts, many minute bubbles contained in the core disappear, and the volume of the melted portion of the core decreases. Therefore, the force that prevents the rotation of the friction cylinder due to frictional force does not become very large, and the friction cylinder can be easily embedded in the core.

Moreover, since the guide member is guided by the core hole as described above, the friction cylinder always rotates around the axis concentric with the core hole even if it is inserted into the core as it melts. Rotate. Therefore, even if the entire length of the core is long, the core can be hollowed out easily and reliably.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

Formworks 31 and 32 forming vertical walls are provided facing each other, as shown in FIG. Formworks 33 and 34 forming horizontal walls are joined to the upper parts of the forms 3 and 32, respectively. Furthermore, a reinforcing bar 35 made of a combination of steel bars is provided between the formworks 31 and 32.

When providing a wiffi hole in a concrete structure formed by such a formwork, first, a rod-shaped holder 36 is placed over the position between the formworks 31 and 32 where the through hole is to be provided. This holder 36 includes, for example, an outer cylinder 36a and an inner cylinder 36.
By rotating the outer cylinder 36a in the direction shown by arrow A, the total length is increased and the formwork 3
It is set to be fixed between 1 and 32.

Next, as shown in FIG. 2, a cylindrical core 37 made of foamed resin such as foamed polystyrene, foamed styrene-polyethylene copolymer, or foamed polyethylene is placed in the holder. 36 to be penetrated and supported. A plurality of these cores 37... are combined so that the total length extends between the formworks 31 and 32, and as shown in FIG.
Make sure it is in close contact with the

The formwork 31~ in which the core 37... was provided in this way
Pour fresh concrete into 34 and allow the concrete to harden. When the concrete hardens and a concrete structure 38 is formed as shown in FIG.
- 34 and holder 36 are removed.

By removing the holder 36, core holes 37b are formed in the cores 37. This core hole 37
As shown in FIG. 5, a rod-shaped guide member 17 constituting the foamed resin punching machine 11 is inserted into b. The foamed resin punching machine 11 has a configuration as shown in FIG. 6, for example.

That is, the friction cylinder 12 that constitutes the drilling machine 11 for foamed resin
A bottom member 13 in which a boss portion 13a and a through hole 13b are formed is connected to one end of the bottom member 13 in a receptacle manner.

The friction cylinder 12 is made of, for example, a chromium molybdenum alloy (
The material is JIS-5-3C35), and the inner and outer surfaces and the open end are finished to a surface roughness of about 100S. Further, the bottom member 13 is provided with roll pin holes 13c, 13c, into which roll pins 14, 14 are fitted.

A roll pin 14.1 is provided on the friction cylinder 12 side of the bottom member 13.
Disc-shaped NAND member 15 whose rotation is prevented by 4
is provided. This disc-shaped NAND member 15 has
A shank member 16 formed with a chuck portion 16a that is attached to a rotation driving means such as a drill 39 is attached to the bottom member 13.
They are screw-fitted by sandwiching them.

On the other hand, a guide member 1 is provided integrally and concentrically with the friction cylinder 12 and guides the friction cylinder 12 so that it advances in the axial direction.
7 is constructed by welding and joining an extruded disk 17b to a rod-shaped shaft member 17a. Shaft member 17 of this guide member 17
The end on the side where the extruded disk 17b is provided in a is fitted into a hole 16b formed in the shank member 1G, and is prevented from being removed by a set screw 18.

The chuck portion 16a of the shank member 16 of the foamed resin drilling machine 11 configured as described above is attached to the drill 39 and rotated at a rotational speed of, for example, 2000 rpm.

Then, the rotational force transmitted to the shank member 16 is transmitted to the neck member 15 via the threaded portion, and further transmitted to the bottom member 13 via the roll pins 14.
The entire foamed resin punching machine 11 rotates.

Therefore, the friction cylinder 12 in the foamed resin drilling machine 11 is guided by the guide member 17 and the core hole part 37b.
Press the tip end face of the core 37 against the exposed end face of the core 37. When the front end surface of the friction cylinder 12 continues to rotate while contacting the core 37, frictional heat is generated at the contact portion, and the core 37 in the vicinity of the contact with the friction cylinder 12 begins to melt locally.

When the core 37 is melted, many minute bubbles contained in the core 37 disappear, so the volume of the melted portion of the core 37 decreases. Therefore, when the friction cylinder 12 is pushed into the core 37 at a feed rate of 20 cm/min, for example, the friction cylinder 2 easily sinks into the core 37.

When the friction cylinder 12 bites in and its inner and outer surfaces come into contact with the core 37, frictional heat is also generated in the contact area and the core 37 melts. Therefore, the rotation of the foamed resin punching machine 11 is not prevented by the frictional force. Moreover, since the guide member 17 is guided by the core hole portion 37b as described above, the friction cylinder I2 is always guided by the core hole portion 37b.
It rotates around an axis concentric with 7b. Therefore, core 37
Even if the core 37 is long, the core 37 can be easily and reliably removed.

The inner surface of the core 37 hollowed out in this way is made smooth by the molten foamed resin, so the portion of the core 37 that remains inside the concrete structure 38 can be used as it is, for example, as a heat insulating material in piping. You can also do it.

In addition, the core 3 remaining in the concrete structure 38
If the outer diameter of the friction cylinder 12 is set so that 7 is thin,
The remaining portion of the core 37 can also be easily removed.

On the other hand, when the drilling work is completed, a hollowed out part of the core 37 remains inside the friction cylinder 12, but this hollowed out part can be removed by loosening the setscrew 18 as shown in FIG. When the guide member 17 is pulled out from the friction cylinder 12, it is pushed out by the pushing disk 17b and can be easily taken out.

〔Effect of the invention〕

As described above, the foamed resin drilling machine according to the present invention spans the rod-shaped holder between the formworks provided facing each other, and
A process of penetrating and supporting a foamed resin core having a length spanning between the formworks with the holder, pouring fresh concrete between the formworks, and removing the formwork and holder after the concrete has solidified. Then, a rod-shaped guide member is inserted into the core hole formed after removing the holder, and while rotating the friction cylinder provided integrally and concentrically with the guide member, the tip surface of the friction cylinder is inserted into the center of the center. The process of hollowing out the core by pressing it against the exposed end surface of the core and propelling the friction cylinder in the axial direction while locally melting the core by the frictional heat generated at the contact area between the friction cylinder and the core. This is a configuration that has

As a result, the core melts locally due to the frictional heat generated at the contact area between the friction cylinder and the core, and the many microscopic bubbles contained in the core disappear, resulting in the volume of the molten part of the core. decreases, the force that prevents the rotation of the friction cylinder due to frictional force does not become very large. In addition, since the guide member is guided by the core hole as described above,
The friction cylinder always rotates around an axis concentric with the core hole.

Therefore, even if the entire length of the core is long, the core can be hollowed out easily and reliably. Therefore, it is possible to form a deep through hole with less distortion in a concrete structure without any difficult work and at a low construction cost.

[Brief explanation of the drawing]

Figures 1 to 6 show an embodiment of the present invention, in which Figure 1 is an explanatory diagram showing the work of installing a holder in a formwork, and Figure 2 is an explanatory diagram showing the work of installing a holder in a formwork, and Figure 2 is a diagram showing how a core is penetrated and supported by a holder. FIG. Fig. 3 is an explanatory diagram showing the core installed in the formwork, Fig. 4 is an explanatory diagram showing the work of removing the holder, Fig. 5 is an explanatory diagram showing the work of hollowing out the core, and Fig. 6 is an explanatory diagram showing the work of removing the holder. FIG. 2 is a vertical cross-sectional front view showing the configuration of a punching machine for foamed resin. 11 is a drilling machine for foamed resin, 12 is a friction cylinder, 17 is a guide member, 31 to 34 are formworks, 36 is a holder, 37 is a core, 37b is a core hole portion, and 38 is a concrete structure.

Claims (1)

[Scope of Claims] 1. A rod-shaped holder is spanned between formworks disposed opposite to each other, and a core made of foamed resin having a length extending between the formworks is penetrated and supported by the holder. After that, fresh concrete is poured between the formworks, and after the concrete has solidified, the formwork and holder are removed, and a rod-shaped guide member is inserted into the core hole formed after the holder is removed, and this guide is removed. While rotating a friction cylinder provided integrally and concentrically with the member, the tip surface of the friction cylinder is pressed against the exposed end surface of the core, and the inside is heated by the frictional heat generated at the contact area between the friction cylinder and the core. A method for drilling a concrete structure, comprising: hollowing out a core by propelling a friction cylinder in the axial direction while locally melting the core.