JPH06264434A - Cement milk injection type down-hole hammer - Google Patents

Abstract

PURPOSE:To pull out a down-hole hammer and simultaneously inject cement milk into a hole, after the hole for a foundation pile has been excavated in the same manner with an excavating case by use of an auger screw. CONSTITUTION:A down-hole hammer 1 connected to a hollow rotary shaft 3 at the lower end thereof is provided with a spiral blade 17 for discharging soil, protruding on the outer peripheral face of the casing 10. The spiral blade 17 is made hollow to form the vacant space as a cement milk way 18. On the other hand, the void of the hollow rotary shaft is used for the supply path of the cement milk. The cement milk way 18 is connected to the lower end of the hollow rotary shaft 3 at the upper end thereof. The opened lower end 18b is positioned at the nearby place of the lower end of the down-hole hammer 1. Or a tubular member 27 using the void of a solid spiral blade 17A as the path of cement milk may be arranged along the solid spiral blade 17A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement milk injecting type in which, after excavating a driving hole for a foundation pile, a downhole hammer can be pulled out from the hole while cement milk can be injected into the driving hole. Regarding downhole hammers.

[0002]

2. Description of the Related Art In civil engineering and construction work, as a conventional construction method for forming foundation piles for receiving structures on the spot, a construction method using a boring device equipped with an auger screw has been performed. This method employs a method of pouring cement milk into the driving hole through the hollow auger screw shaft at the same time as pulling up the auger screw after finishing excavating the driving hole of the foundation pile with the auger screw. In addition to auger screws, drilling equipment called downhole hammers are also used as boring equipment. This downhole hammer is used by attaching it to the lower end of a rotating shaft (auger screw screw shaft, etc.) supported so that it can move up and down, and the excavating bit assembled at the lower end repeats itself with an internal air hammer. Since it has a structure that rotates while being hit, it is possible to easily excavate even on hard ground where the auger screw has no teeth.

[0003]

However, in the case of the downhole hammer, unlike the auger screw, a simple construction method in which the downhole hammer that has been excavated is pulled up and cement milk is injected cannot be adopted. This is because the conventional downhole hammer has no room for providing a cement milk flow-down passage inside the hammer due to its structure, and the cement milk cannot be delivered to the lower end of the downhole hammer. Therefore, the object of the present invention is, as in the case of the auger screw, when digging up the casting hole of the foundation pile and pulling it up, it is possible to inject the cement milk that is the material of the foundation pile at the same time. It is in providing downhole hammers.

[0004]

To achieve the above object, a cement milk injection type downhole hammer according to the present invention is used by being connected to a lower end of a hollow rotary shaft 3 and used. A cement milk feed passage 8 is formed in the inner space of the shaft 3, and a spiral blade 17 for earth removal is provided on the outer peripheral surface of the casing 10 of the downhole hammer 1 so that the spiral blade 17 is hollow. Shaped like a cement milk flow channel 18 and its inner space is used as the cement milk flow channel 18.
The upper end of 18a is connected to the lower end of the cement milk feed passage 8 so that the open lower end 18b of the cement milk flow passage 18 faces the vicinity of the lower end of the downhole hammer 1. Alternatively, a spiral blade 17A for earth removal is provided on the outer peripheral surface of the casing 10 of the downhole hammer 1, and a tube-shaped member 27 whose inner space serves as a cement milk injection path is provided.
Along the entire length of the spiral blade 17A, the upper end of the tube-shaped member 28 is connected to the lower end of the cement milk feeding path 8, and the open lower end 28b of the tubular member 28 is near the lower end of the downhole hammer 1. You may make it the structure which faces. The hollow rotary shaft 3 may be the auger screw shaft of the auger screw 2.

[0005]

[Operation] The hollow rotary shaft 3 is used to excavate the driving hole of the foundation pile.
When the air hammer incorporated in the downhole hammer 1 is operated while rotating the driving means, the excavating bit assembled at the lower end of the downhole hammer 1 rotates while being repeatedly hit, and the solid ground is also efficient. Dig into. After the excavation is completed, while the downhole hammer 1 is pulled up while supplying the cement milk to the inner space of the hollow rotary shaft 3, the lower end of the hollow rotary shaft 3 reaches the lower end and the cement milk is discharged from the casing 10 of the downhole hammer 1. From the upper end 18a of the cement milk flow path 18 formed in the inner space of the spiral blade 17 projecting on the outer peripheral surface thereof, and hitting from the open lower end 18b thereof facing the lower end of the downhole hammer 1, It is filled in the installation hole. And
When the tubular member 27 is placed along the solid spiral blade 17A, the cement milk flows from the lower end of the hollow rotary shaft 3 to the inner space of the tubular member 27 and flows down to the lower end of the downhole hammer 1. And reaches the pouring hole.
When the screw shaft of the auger screw 2 is used as the hollow rotary shaft 3, the cutting dust generated by the downhole hammer 1 is the spiral blade 1 provided on the outer peripheral surface of the casing 10.
7, 17A and the auger screw provided on the auger screw 2 cooperate to push the auger screw 2 to the ground.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the downhole hammer 1 of this embodiment is used with its upper end detachably connected to the lower end of the auger screw 2. Figure 1
The whole structure of the excavator equipped with the downhole hammer 1 is shown in FIG. Reference numeral 50 in the figure denotes a machine body provided with a caterpillar 51 for movement, and a leader 53 supported by two leader stays 52 is provided upright on the front portion of the machine body 50. The leader 53 has an earth auger 54
Is assembled so as to be vertically movable along a guide rail (not shown) provided over substantially the entire height of the leader 53. A winch (not shown) installed inside the machine body 50
The auger suspending wire 55 fed out from the wire is stretched over the wire sheep 56 provided at the upper end of the leader 53 and extended downward, and the earth auger 54 is provided at the end thereof.
Is suspended and supported.

An auger motor 57 with a speed reducer is incorporated in the earth auger 54, and the output shaft thereof is connected to the upper end of the auger screw shaft 3 of the auger screw 2. In this embodiment, the auger screw shaft 3 corresponds to the hollow rotating shaft according to the present invention, and the outer peripheral surface thereof is provided with the auger screw blades 4 for soil discharge. At the lower end of the auger screw shaft 3, as shown in FIG. 2, a coupler 5 for detachably connecting the upper end of the downhole hammer 1 described below is attached. The coupler 5 is provided with a female screw 6 for connecting the downhole hammer 1.

Inside the auger screw shaft 3, compressed air supplied from an air compressor (not shown),
An air supply pipe 7 for feeding the downhole hammer 1 is coaxially arranged. The tubular space around the air supply pipe 7 is used as the cement milk feeding path 8. At the upper end of the cement milk feeding passage 8, a hose joint (neither shown) is provided to connect the end of a pressure feeding hose extending from the cement milk feeding device. The lower end of the cement milk feeding passage 8 is communicated with a feeding hole 9 formed in the coupler 5 in a vertically penetrating manner.

The downhole hammer 1 shown in FIGS.
Is equipped with a cylindrical casing 10, and a piston (hammer) 11 that is loosely fitted inside and moves up and down repeatedly strikes an excavating bit 12 assembled in a lower portion of the casing 10 in a loosely fitted state. It has become. The piston 11 is
By the cooperation of the air valves 13 and 14 provided on the upper and lower sides of the piston 11, the compressed air is alternately supplied to the upper and lower sides of the piston 11 to move up and down. A male screw portion 1 is screwed on the open upper end of the casing 10 and is screwed onto a female screw 6 provided on the lower end of the auger screw shaft 3 on the upper surface thereof.
6 is projected. Also, on the outer peripheral surface of the casing 10,
The spiral blade 17 for earth removal is attached over its entire height. The pitch and outer diameter of the spiral blade 17 are the same as those of the auger screw blade 4.

The spiral blade 17 of this embodiment is formed into a rectangular tubular body or a trough-shaped body having a U-shaped cross section, as shown in FIG. The empty space is the cement milk flow path 18. The spiral blade 17 need only fulfill the role of pushing up the excavated dust toward the surface of the earth and the role of the cement milk as a downflow path, so that the spiral blade 17 is not limited to the rectangular tube shape, but may be formed in a triangular tube shape, a cylindrical shape, or the like. Good.

In the drill bit 12 of this embodiment, as shown in FIG. 2, the shaft portion 21 constituting the upper half portion thereof is a spline shaft, and each of the protrusions is formed on the inner peripheral surface of the lower portion of the casing 10. It is fitted in each of the vertical grooves that are provided in the circumference. Therefore, the excavation bit 12 can be rotated integrally with the casing 10 and can be vertically moved with respect to the casing 10. An annular groove 22 is provided around the upper end of the shaft portion 21, and a retainer ring 23 provided in the lower portion of the casing 10 is projected into the annular groove 22 to regulate the vertical movement stroke of the drill bit 12. is doing.

The bit main body 24 constituting the lower half of the excavating bit 12 is formed in a thick disk shape, and a plurality of vertical grooves 25 are vertically provided through the outer peripheral surface thereof at equal intervals. ing. The vertical groove 25 serves as a passage for discharging soil that pushes up excavation waste toward the surface of the earth during excavation, and serves as a flow-down passage when pouring cement milk. Further, a large number of chips 26 for digging are planted on the bottom surface and the outer peripheral surface. Further, an exhaust hole 27, which serves as an escape path for the used compressed air, is vertically provided through the shaft center of the drill bit 12 so as to penetrate therethrough.

Next, the operation of the above configuration will be described. First,
To excavate the driving hole for driving the foundation pile, the machine body 50
Move the winch and operate the winch to move the drill bit 1
When the auger motor 57 is activated and compressed air is supplied to the downhole hammer 1 after bringing 2 into the excavated place on the surface of the earth, the auger screw 2 and the downhole hammer 1 connected to the lower end thereof start to rotate.
Therefore, the excavation bit 12 assembled to the downhole hammer 1 rotates while being repeatedly hit by the air hammer, and excavates the ground. Dust generated by the excavation is pushed upward through the vertical groove 25 provided in the drill bit 12, and by the action of the spiral blade 17 provided on the outer peripheral surface of the downhole hammer 1, up to the lower end of the auger screw 2. Pushed up. The scraps thus pushed up are inherited by the auger screw blades 4 of the auger screw 2 and discharged to the ground.

After digging the casting hole of a predetermined depth, the cement milk feeding device is operated, and the earth auger 54 is pulled up by the winch. After passing through the cement milk feed passage 8 and the feed hole 9 provided in the coupler 5, the cement milk flow passage 18 formed in the spiral blade 17 flows into this passage from the upper end 18a. The open lower end 18 located near the lower end of the downhole hammer
The cement milk discharged from b flows down in the vertical groove 25 provided on the outer peripheral surface of the drill bit 12, and is filled into the cavity (placement hole) generated as the downhole hammer 1 is pulled up.

When the downhole hammer 1 is completely pulled up to the ground and the casting hole of the foundation pile is filled with cement milk, the H-shaped steel is inserted into the casting hole filled with cement milk in the same manner as in the conventional method. If steel pipes or steel pipes are pushed in, the foundation pile laying work can be completed very easily and quickly, without any significant noise or vibration.

FIG. 5 shows another embodiment of the present invention. The difference from the above embodiment is that a solid spiral blade 17A is used and instead of this, the tubular member 27 is replaced by the spiral blade 1.
It is in the place of being attached over the entire length of 7A. in this case,
The inner space of the tubular member 27 serves as a cement milk flow path. The upper end of the tubular member 27 communicates with the delivery hole 9 provided in the coupler 5. Tubular member 27
The sectional shape of is not limited to the illustrated circular shape, and may be, for example, a triangular tube shape.

In the above structure, the object of the present invention can be achieved even if the detailed structure is appropriately changed in design. For example,
Unlike sandy or gravel soil, when dedicated to solid ground where compressed air does not easily dissipate, instead of the auger screw 2, a simple hollow rotary shaft 3 is used, and it is used as compressed air for downhole hammering. The soil may be discharged in cooperation with the spiral blade 17. Further, as a method of connecting the hollow rotary shaft 3 and the downhole hammer 1, instead of the connection by screwing, a connecting bolt may be used. Alternatively, the lower surface of the excavating bit 12 may be formed into a conical surface, a truncated conical surface, or the like depending on the hardness of the excavated ground.

[0018]

As is apparent from the above description, in the cement milk injection type downhole hammer according to the present invention, the inner space of the hollow rotary shaft for rotating the downhole hammer is used as the cement milk feed path, and A spiral blade attached over the entire height of the outer peripheral surface of the casing of the downhole hammer is formed into a hollow shape, and this inner space is used as a cement milk flow path, or a tube serving as a cement milk flow path. -Shaped member is attached over the entire length of the spiral blade,
By configuring the upper end of the hollow spiral blade or the tubular member to communicate with the lower end of the hollow rotating shaft, various excellent practical effects as listed below can be obtained. (A) It was possible to dig a casting hole in a foundation pile using an auger screw. While pulling up the auger screw from the hole that has been dug, cement milk is injected into the casting hole through a hollow screw shaft. The extremely efficient foundation pile driving method can be applied to the excavation method using a downhole hammer, which was not possible in the past. (B) Therefore, even for hard ground that can only be dug with a downhole hammer, just as with the screw excavator that can only be used for soft ground, the above-mentioned extremely efficient construction method can be applied. Become. (C) If an auger screw is used as a hollow rotary shaft for rotating the downhole hammer, the cutting waste is pushed to the ground by the spiral blade provided on the outer peripheral surface of the downhole hammer and the auger screw blade in cooperation with each other. Give me (D) Therefore, as in the conventional method, the method of pushing out the cutting waste by using the used compressed air of the downhole hammer requires a large-capacity compressor in the case of sandy or gravel ground where the dissipation of compressed air is remarkable. It also solves the problem of saying that it is necessary.

[Brief description of drawings]

FIG. 1 is a side view of the entire apparatus showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view of the downhole hammer of the same.

FIG. 3 is a side view of the downhole hammer of the above.

FIG. 4 is an enlarged vertical sectional view of the vicinity of the upper end of the spiral blade of the above.

FIG. 5 is a view corresponding to FIG. 4, showing another embodiment of the present invention.

[Explanation of symbols]

 1 Downhole hammer 2 Auger screw 3 Auger screw shaft (hollow rotating shaft) 4 Auger screw blade 5 Coupler 6 Female screw 7 Air supply pipe 8 Cement milk feeding passage 9 Outlet hole 10 Casing 11 Piston 12 Drilling bit 13,14 Air valve 15 Plug 16 Male thread 17, 17A Spiral blade 18 Cement milk flow path 21 Shaft 22 Annular groove 23 Retainer ring 24 Bit main body 25 Vertical groove 26 Excavation tip 27 Tubular member 50 Machine main body 51 Front cover 52 Backstay 53 Leader 54 Earth Auger 55 Auger Suspended Wire 56 Wire Sheep 57 Auger Motor

Claims (3)

[Claims] 1. The hollow rotary shaft 3 is used by being connected to the lower end thereof, wherein the hollow rotary shaft 3 has a cement milk feed passage 8 formed in its inner space, A spiral blade 17 for earth removal is provided on the outer peripheral surface of the casing 10, and the spiral blade 17 is formed in a hollow shape to form a cement milk flow passage 18 in its inner space. The upper end 18a is connected to the lower end of the cement milk feed passage 8, and the open lower end 18b of the cement milk flow passage 18 is connected to the downhole hammer 1
Cement milk injection type downhole hammer characterized by facing near the lower end of the. 2. The hollow rotary shaft 3 is used by being connected to a lower end thereof, wherein the hollow rotary shaft 3 has a cement milk feeding passage 8 formed in an inner space thereof, A spiral blade 17A for earth removal is provided on the outer peripheral surface of the casing 10, and a tube-shaped member 27 having an inner space thereof as the cement milk flow path 18 is provided along the entire length of the spiral blade 17A. The upper end of the tubular member 27 is connected to the lower end of the cement milk feeding passage 8, and the open lower end of the tubular member 27 is exposed near the lower end of the downhole hammer 1. Cement milk injection type downhole hammer. 3. The cement milk injection type downhole hammer according to claim 1, wherein the hollow rotary shaft 3 is filled with an auger screw shaft of an auger screw 2.