JP2002256788A - Double tube excavator for rotary table machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double tube excavator capable of entrained easing drilling by means of a retract bit by using a rotary table machine. SOLUTION: This double tube excavator is provided with a drive bush 11, a easing 6 engaged in the inner circumference of the drive bush via the outer circumference for receiving rotational driving force transmitted from the drive bush 11, a kelly rod 5 provided with the freely extensible retract bit 7 arranged at the tip and housed inside the casing 6 for entraining the casing in the excavation direction, and a sub-subsidiary bush 17 engaged in the upper end part of the casing 6 at the lower end part while engaged around the outer circumference of the kelly rod 5 via the inner circumference for transmitting the rotational driving force from the casing 6 to the kelly rod 5. In the sub-subsidiary bush 17, when it reaches the drive bush 11 position by excavation and its upper end part is engaged with the drive bush, engagement with the upper end part of the casing 6 is released while its outer circumference is engaged with the inner circumference of the drive bush for transmitting the rotational driving force transmitted from the drive bush to the kelly rod 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double pipe drilling machine for a rotary table machine, and more particularly, to a drilling machine for a rotary table machine.
The present invention relates to a double pipe excavator for drilling a hole while protecting a hole wall with a casing serving as an outer pipe.

[0002]

2. Description of the Related Art Conventionally, when excavating a pilot hole for an earth retaining pile or a landslide prevention pile on a slope, a double pipe excavation method has been applied to prevent collapse of a hole wall due to excavation. In this double pipe excavation method, a hole having a larger diameter than the protective casing is excavated by the retract bit while the outer pipe (protective casing) is entrained by the retract bit provided at the tip of the inner pipe. It is a construction method to prevent.

[0003] However, this double pipe excavation method requires a large base machine as a boring machine in order to use a retract bit. For this reason, there is a problem that construction is difficult in a narrow place or a site where a site loading path cannot be secured, and the cost of the site increases because the temporary construction becomes large.

A rotary table machine has been conventionally known as one of the boring machines. This rotary table machine has the advantages that it is lightweight and compact, can be installed in a narrow place, does not require a large space for the site entrance path, and requires only a small temporary installation.

[0005] However, the rotary table machine cannot be immediately applied to the double pipe excavation method. That is, the double pipe excavation method is a method in which only the inner pipe is reversed to reduce the retract bit after excavating to a predetermined depth and the inner pipe is pulled up while leaving the outer pipe. Even if the excavation is performed by transmitting rotation to the pipe, only the inner pipe cannot be rotated due to the mechanism of the rotary table machine when the inner pipe is pulled up.

[0006]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above technical background, and has the following objects. It is an object of the present invention to provide a double pipe excavating apparatus that enables a casing to be excavated by a retract bit using a rotary table machine.

[0007]

The present invention employs the following means to achieve the above object. That is, according to the present invention, a drive bush whose outer periphery is engaged with an inner periphery of a rotary table of a rotary table machine and rotates, and an outer periphery is engaged with an inner periphery of the drive bush, and its rotational driving force is transmitted. A casing, a retractable retractable bit provided at an end thereof, a kelly rod housed inside the casing and entraining the casing in a digging direction, a lower end at an upper end of the casing, and an inner periphery at the kelly rod. A bush that is engaged with the outer periphery of the drive bush and transmits the rotational driving force transmitted from the casing to the kelly rod, and when the drive bush position is reached by excavation, the upper end is engaged with the drive bush. As a result, the engagement with the upper end of the casing is released, and the outer periphery is Combined and, in the double pipe drilling apparatus for rotary table machines, characterized by comprising a grandchild bush which transmits the rotational driving force transmitted from the drive bush to the kelly rod.

[0008] More specifically, the lower end bush of the grandchild bush is engaged with the inner circumference of the upper end of the casing, and in the engaged state, the outer circumferences of the grandchild bush and the casing are substantially flush. . A plurality of ridges are provided along the axial direction on the outer periphery of the lower end of the grandchild bush, and a plurality of cut grooves are provided on the upper end of the casing to engage with the ridges. The grandchild bush is provided at its upper end with a flange that engages with the upper end of the drive bush.

Further, an air pipe for supplying air to a gap between the kelly rod and the casing is provided on an outer periphery of the kelly rod. An air swivel is provided on the outer periphery of a support shaft that suspends and supports the Kelly rod, and the air swivel communicates with the air pipe via an air passage provided inside the support shaft.

According to the present invention, at the start of excavation, the rotational driving force of the rotary table is transmitted to the Kelly rod via the drive bush, the casing, and the grandchild bush, and the casing is excavated by the retract bit.
When the grandchild bush reaches the drive bush by excavation, the upper end of the grandchild bush is engaged with the drive bush, and the engagement between the grandchild bush and the casing is released. Also,
The inner and outer circumferences of the drive bush and grandchild bush are engaged,
The rotational driving force of the drive bush is transmitted from the grandchild bush to the Kelly rod without passing through the casing. Therefore, since the rotation of the Kelly rod continues, the casing can be excavated even after the casing has passed through the drive bush. Further, even after reaching the predetermined excavation depth, the Kelly rod can be reversed via the grandchild bush, and the retract bit can be reduced in diameter, and the Kelly rod can be pulled up and collected.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram of construction by a double pipe excavator of the present invention, and shows an example of excavating a pile hole on an inclined surface. The rotary table machine 1 is installed on a temporary scaffold 2, and a double tube 3 composed of a protective casing and a Kelly rod driven by the rotary table machine 1 is suspended and supported by a rough terrain crane 4.

FIG. 2 is a diagram showing the structure of a double tube. The double pipe excavator according to the present invention includes a drive bush and a grandchild bush, which will be described later, in addition to the kelly rod 5 shown in FIG. 2A and the protective casing 6 shown in FIG. A plurality of Kelly rods 5 are used.
Has a built-in down-the-hole hammer (not shown). The retract bit 7 provided at the tip of the Kelly rod 5 is a retractable bit, and is connected to a down-the-hole hammer to transmit an impact force.

A plurality of flat bars 8 are provided on the outer periphery of the kelly rod 5 along the axial direction.
The number of flat bars 8 is four in this example. A pipe (not shown) for supplying air to the down-the-hole hammer is provided inside the kelly rod 5, and each kelly rod 5 is connected via a joint connecting the pipes.

The Kelly rod 5 is housed inside a protective casing 6. In this state, the retract bit 7 engages with the inner periphery of the tip shoe 9 of the protective casing 6, and the kelly rod 5 can carry the protective casing 6 with the excavation. A flat bar 10 as a plurality of protrusions is provided on the outer periphery of the protective casing 6 along the axial direction. The number of flat bars 10 is six in this example.

FIG. 3 is an axial sectional view of the drive bush.
FIG. 4 is a sectional view taken along line AA of FIG. The drive bush 11 is cylindrical and has a flange 12
Is provided. A plurality of grooves 13 are provided in the flange 12 along the axial direction, and the drive bush 11 rotates by engaging the projections 15 of the rotary table 14 shown by chain lines in FIG. 4 with these grooves. A plurality of grooves 16 are provided on the inner periphery of the drive bush 11 along the axial direction. The flat bar 10 of the protective casing 6 is engaged with the groove 16, and the rotational driving force of the drive bush 11 is transmitted to the protective casing 6. That is, the number of the grooves 16 is six like the number of the flat bars 10.

FIG. 5 is an axial sectional view of the grandchild bush, and FIG. 6 is a sectional view taken along line BB of FIG. The grandchild bush 17 has a cylindrical shape, and is provided with a flange 18 at an upper portion thereof which can be engaged with the upper end of the drive bush 11. Grandson bush 1
A stepped portion 19 is formed on the outer periphery of the lower end portion of the bush 7, and the grandchild bush 17 includes a thick portion 20 above the stepped portion and a thin portion 21 below the stepped portion. A plurality of ridges 22 are provided on the outer periphery of the thin portion 21 along the axial direction.

On the other hand, as shown in FIG. 7, the same number of cut grooves 23 as the ridges 22 are formed at the upper end of the protective casing 6. The protective casing 6 is fitted on the outer periphery of the thin portion 21 until it contacts the stepped portion 19 of the grandchild bush 17, and in this state, the ridge 22 and the cut groove 23 engage. Thus, the rotational driving force transmitted to the protective casing 6 is transmitted to the grandchild bush 17. In a state where the protective casing 6 is fitted to the grandchild bush 17, the outer periphery of the thick portion 20 and the outer periphery of the protective casing 6 are flush. That is, the outer diameter D ₁ of the thick portion 20 is equal to the outer diameter D ₁ of the protective casing 6. In other words, the thick portion 20 and the thin portion 21
Outer diameter difference D ₁ -D ₂ with is the thickness t of the protective casing 6, and also any protruding thickness t of the ridge 22.

Referring again to FIG. 5 and FIG.
A plurality of grooves 24 are provided in the inner periphery of 7 along the axial direction. The flat bar 8 of the Kelly rod 5 fitted in the grand bush 17 is engaged with the groove 24, and the Kelly rod 5
The rotational driving force is transmitted to the motor. That is, the number of the grooves 24 is four like the number of the flat bars 8. Grandson bush 17
A flat bar 25 as a plurality of protrusions is provided along the axial direction on the outer periphery of the thick portion 20 in FIG.

The number of the flat bars 25 is the same as that of the flat bars 10 of the protective casing 6, that is, six. The flat bar 25 is axially aligned with the flat bar 10 of the protective casing 6 when the grandchild bush 17 and the protective casing are fitted. Therefore, when the grandchild bush 17 reaches the position of the drive bush 11 by excavation, the flat bar 25 of the grandchild bush 17 engages with the groove 16 of the drive bush 11, and the rotational driving force is directly transmitted from the drive bush 11 to the grandchild bush 17. Is done.

During excavation, if the gap between the protective casing 6 and the kelly rod 5 is clogged with slime or mud, it becomes difficult to pull out and collect the kelly rod 5. A plurality of air pipes 2 for discharging the slime and the like by an air lift
6 are arranged along the axial direction on the outer periphery of the Kelly rod 5 (see FIG. 2). As shown in FIG.
A groove 27 provided along the axial direction on the inner periphery of 7 is for passing these air pipes 26.

As shown in FIG. 2, a support shaft 31 for suspending and supporting by a rough terrain crane is connected to an upper end of the kelly rod 5 via a joint 30. Air is supplied to the support shaft 31 by a down-the-hole hammer. An air swivel 32 for supplying air and an air swivel (hereinafter, referred to as an intermediate air swivel) 33 for supplying air to the air pipe 26 for discharging slime or the like are provided.

FIG. 8 is a partial sectional view showing details of the intermediate air swivel 33. As shown in FIG. The intermediate air swivel 33 is the support shaft 31
Has an air inlet 34 connected to an air supply source (not shown) so as to be rotatable on the outer periphery thereof, and an annular flow passage 35 on the inner periphery. An air passage 36 for supplying air to the down-the-hole hammer is provided on the axis inside the support shaft 31,
Further, a plurality of air flow paths 37 communicating with the annular flow path 35 are provided so as to surround the flow path 36. The air passage 37 has an outlet 38 at a lower portion, and the outlet 38 communicates with the air pipe 26 via a connecting hose 39. With such a configuration, the air that has entered from the inflow port 34 is supplied to the air pipe 26 through the annular channel 35, the channel 37, and the connection hose 39.

Next, a construction method using the above-mentioned double pipe excavator will be described. 9 and 10 are front views showing states at the start of excavation and at the end of excavation, respectively. The kelly rod 5 is housed in the protective casing 6 to form the double tube 3, and the grandson bush 17 is fitted to the kelly rod 5,
The protrusion 22 at the lower end of the grandchild bush 17 is
Is engaged with the cut groove 23 at the upper end.

On the other hand, the rotary table machine 1 has
The drive bush 11 is attached to the rotary table 14 shown in FIG.
Is set, and the flat bar 10 of the protective casing 6 is engaged with the groove 16 of the drive bush 11. Then, excavation is started while the double pipe 3 is suspended by the rough terrain crane.

At the time of excavation, the rotational driving force transmitted from the rotary table 14 to the drive bush 11 is transmitted to the protective casing 6, and further, the rotational driving force is transmitted by engagement of the cut groove 23 and the ridge 22 of the grandchild bush 17. Is transmitted to the grandson bush 17. Further, the rotational driving force transmitted to the grandchild bush 17 is applied to the inner peripheral groove 24 and the flat bar 8.
Is transmitted to the Kelly rod 5. In this way, the Kelly rod 5 rotates, a hole larger than the protective casing 6 is excavated by the retracted retract bit 7, and the protective casing 6 is carried to the retract bit 7 with the excavation.

When the excavation proceeds and the grandchild bush 17 reaches the position of the drive bush 11, the grandchild bush 17 enters the drive bush 11, as shown in FIG. And the groove 16 of the second member are engaged. Further, the flange 18 of the grandchild bush 17 is engaged with the upper end of the drive bush 11, so that the grandchild bush 17 is prevented from descending.
And the protective casing 6 is disengaged.

As a result, the rotational driving force of the drive bush 11 is directly transmitted to the grandchild bush 17 without passing through the protective casing 6, and the excavation in which the protective casing 6 is entrained by the rotation of the Kelly rod 5 is continued. The protective casing 6 detached from the grandchild bush 17 rotates until it passes through the drive bush 11, but after passing through the drive bush 11, it is merely driven by the kelly rod 5 and does not rotate. Then, when the excavation depth reaches a predetermined depth, the rotary table 14 is reversed, whereby the Kelly rod 5 is reversed via the drive bush 11 and the grandchild bush 17, and the retract bit 7 is reduced in diameter. As a result, the retract bit 7 can pass through the inside of the protective casing 6, and the Kelly rod 5 is pulled up and collected with the protective casing 6 remaining.

During excavation, air is sent from the intermediate air swivel 33 to the air pipe 26, and this air is blown into the gap between the protective casing 6 and the Kelly rod 5. Thereby, the slime and mud clogged in the gap can be discharged to the ground by the air lift action.

The above embodiment is merely an example, and the present invention can be variously modified. For example, by preparing a plurality of drive bushes having different inner diameters, it is possible to cope with different excavation diameters. The number of flat bars or ridges provided on the protective casing, the Kelly rod, and the like for transmitting rotation is changed according to the required load torque.

[0030]

As described above, according to the present invention, the casing can be excavated by the retract bit using the rotary table machine. Therefore, double pipe excavation work can be performed in a narrow place, and a small space is sufficient for a site carrying-in path, and only a small temporary construction is required, so that the site construction cost can be reduced. In addition, the working speed can be improved by using together with the rough terrain crane.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of construction by a double pipe excavator of the present invention.

FIG. 2 is a diagram showing a configuration of a double pipe.

FIG. 3 is an axial sectional view of a drive bush.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is an axial sectional view of a grandchild bush.

FIG. 6 is a sectional view taken along line BB of FIG. 5;

FIG. 7 is a diagram showing an engagement relationship between a protective casing and a grandchild bush.

FIG. 8 is a partial sectional view showing details of an intermediate air swivel.

FIG. 9 is a front view showing a state at the start of excavation.

FIG. 10 is a front view showing a state at the end of excavation.

[Explanation of symbols]

 1: Rotary table machine 3: Double pipe 4: Rough terrain crane 5: Kelly rod 6: Protective casing 7: Retract bit 8: Flat bar 9: Tip shoe 10: Flat bar 11: Drive bush 12: Flange 12: Groove 14: Rotary table 15: Ridge 16: Groove 17: Grandson bush 18: Flange 19: Stepped part 20: Thick part 21: Thin part 22: Ridge 23: Cut groove 24: Groove 25: Flat bar 26: Air pipe 31: Support shaft 33: Intermediate air swivel

Claims (6)

[Claims] 1. A drive bush whose outer periphery is engaged with an inner periphery of a rotary table of a rotary table machine and rotates, and a casing whose outer periphery is engaged with an inner periphery of the drive bush and the rotational driving force is transmitted. A retractable retractable bit is provided at the tip, a kelly rod housed inside the casing and entraining the casing in the excavation direction, a lower end at the upper end of the casing, and an inner periphery at the inner periphery of the kelly rod. A grandchild bush that is engaged with the outer periphery and transmits the rotational driving force transmitted from the casing to the Kelly rod, and when the drive bush position is reached by excavation, the upper end engages with the drive bush. As a result, the engagement with the upper end of the casing is released, and the outer periphery is engaged with the inner periphery of the drive bush. Rotary Table double pipe drilling device for machines, characterized by comprising a grandchild bush which transmits the rotational driving force transmitted from the drive bush to the kelly rod. 2. The grandchild bush has a lower end outer periphery engaged with an upper end inner periphery of the casing, and in the engaged state, the outer periphery of the grandchild bush and the casing are substantially flush. The double pipe excavator for a rotary table machine according to claim 1. 3. A plurality of ridges extending in the axial direction are provided on an outer periphery of a lower end portion of said grandchild bush, and a plurality of kerfs are provided on an upper end portion of said casing to engage with said ridges. The double pipe excavator for a rotary table machine according to claim 2, wherein 4. The double for a rotary table machine according to claim 1, wherein said grandchild bush is provided with a flange at an upper end thereof for engaging with an upper end of said drive bush. Pipe drilling rig. 5. An air pipe for supplying air to a gap between the kelly rod and the casing is provided on an outer periphery of the kelly rod. 4. A double pipe drilling machine for a rotary table machine according to 4. 6. An air swivel is provided on an outer periphery of a support shaft for suspending and supporting the Kelly rod, and the air swivel communicates with the air pipe via an air passage provided inside the support shaft. The double pipe excavator for a rotary table machine according to claim 5, wherein