JPS63184612A - Excavator for expanded bottom - Google Patents

Abstract

PURPOSE:To effectively excavate an expanded bottom by a method in which a switch valve is provided between an oil-pressure cylinder to open or close a bottom-expanding blade and an oil-pressure cylinder to open or close a rotary excavating blade, and vertically uprising excavation is made for expanded bottom. CONSTITUTION:Vertically uprising excavation for expanded bottom is made by a tip bit 11 and a rotary excavating blade 12. A switch valve 24 for switching the supply and discharge of pressure oil for an oil-pressure cylinder 20 is provided between an oil-pressure cylinder 16 to open or close a bottom- expanding blade 10 and the oil-pressure cylinder 20 to open or close the blade 12. Only the cylinder 16 can be operated by closing a valve 33 in the oil-pressure circuit. The excavating efficiency can thus be raised, and the trouble of shortage in rigidity to excavating torque can also be obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bottom-expanding excavator, and particularly to a bottom-expanding excavator used in a reverse circulation drill.

[Conventional technology]

When drilling a hole for vertical shaft construction underground using a reverse circulation drill, the diameter of the bottom is enlarged relative to the shaft.
Increasingly, the method of expanding the diameter of the pile, which provides greater bearing capacity at the tip of the pile, is being adopted. The shape of the expanded hole is often relatively short, with the vertical rising dimension of the expanded bottom being 30 to 50 countries, as shown in Figure 4 (a), but in some cases the vertical rise dimension of the expanded bottom is relatively short, as shown in Figure 4 (b). As shown, the vertical rising dimension of the expanded bottom portion may be several meters. By increasing the vertical upright dimension, the supporting force of the tip of the pile to be constructed can be sufficiently exhibited, the rigidity of the supporting force mechanism can be increased, and the peripheral surface friction force of the pile tip can be increased.

An example of a bottom-expanding excavator used in the above-mentioned bottom-expanding method is as described in JP-A-58-146694.

Equipped with multiple expanded bottom wings that can be opened and closed, the shaft of the support pile hole is excavated with the expanded bottom wings closed, and once the shaft of the specified length has been dug, the expanded bottom wings are expanded to excavate the expanded bottom part. There is an excavator. [Problems to be Solved by the Invention] In the above-mentioned prior art, when excavating the expanded bottom portion of the support pile hole with a long vertical vertical dimension as shown in FIG. The entire excavator will then be lowered. However, excavating a long vertical rise with the expanded bottom blade not only has poor excavation efficiency, but also has the problem that the bottom expansion blade lacks rigidity relative to the excavation torque.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bottom-expanding excavator that can efficiently excavate a wide-bottomed section with a long vertical vertical dimension in a hole for constructing a bottom-expanded pile without relying on a bottom-expanding blade. .

[Means for solving problems]

The above purpose is to provide a bottom-expanding excavator that attaches a bottom-expanding bit to the lower end of a drill pipe and rotates the bottom-expanding bit with the drill pipe to drill a hole for installing a bottom-expanding pile. A plurality of expandable bottom wings that can be opened and closed, a tip bit fixed to the lower end of the drill pipe, and pins connected to both ends of the tip bit, so that the tip bit can be opened and rotated in the extending direction and rotated in the direction of the drill pipe. It consists of a rotary drilling blade that can be closed and rotated, a hydraulic cylinder that is attached to a drill pipe and opens and closes the expanded bottom blade, and a hydraulic cylinder that opens and closes the rotary digging blade. This is achieved by allowing the dynamic excavation blades to be opened and closed separately.

[Effect]

Once the shaft part of the hole for expanding pile construction is excavated to a specified length with the expanded bottom blade closed, the expanded bottom blade is expanded using a hydraulic cylinder to excavate the expanded bottom part a little, then the expanded bottom blade is closed, and the hydraulic cylinder performs rotary excavation. The blades are opened and the expanded bottom portion is excavated to a predetermined length using the rotary excavation blade and the tip bit. Since the expanded bottom part having such a long vertical rise can be excavated using the rotary excavation blade and the tip bit, the expanded bottom part can be excavated efficiently and the problem of insufficient rigidity with respect to the excavation torque can be solved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a side view of a bottom-expanding excavator according to the present invention, and FIG. 2 is an overall side view of a reverse circulation drill equipped with the bottom-expanding excavator to drill a hole for constructing a bottom-expanding pile. In Fig. 2, the reverse circulation consists of a frame 1, a suction pump 2, a suction hose 3, a swivel joint 4. A hydraulic unit 5, a hydraulic hose 6, a kely bar 7, etc. are arranged, and a drill pipe 8 is installed for transmitting torque to the excavation hole being excavated.The drill pipe 8 is attached to the lower end of the drill pipe 8 to excavate underground and at the end of the excavation hole. It is configured by arranging a bottom expanding bit 9, etc., which expands in diameter as it reaches this point.

As shown in FIGS. 1 and 2, the bottom expanding bit 9 includes a plurality of bottom expanding blades 1O, a tip bit 11, and a rotary excavating blade 12. The upper end of each expanded bottom wing 10 is pivoted to a flange portion 13a of a center pipe 13 connected to the lower end of the drill pipe 8. Further, a substantially middle portion of each expanded bottom wing 1O is connected to a slider 15 via a link 14. The slider 15 is fitted to the outer periphery of the center pipe 13 so as to be movable up and down, and is connected to the rod 1 of the hydraulic cylinder 16.
6a is connected to the lower end. A base end of the hydraulic cylinder 16 is connected to a bracket 13b of the center pipe 13. Therefore, the slider 15 moves up and down due to the expansion and contraction of the rod 16a of the hydraulic cylinder 16, and the distance of the link 14 from the center of the center pipe 13 changes accordingly.
The 10th expansion wing is opened and closed. In other words, hydraulic cylinder 1
The amount of contraction of the rod 16a of No. 6 corresponds to the amount of opening of the expanded bottom blade 10.

The tip bit 11 is fixed to the lower end of the center pipe 13. The rotary excavation blade 12 is connected to the outer circumferential end of the tip bit 11 via a pin 17, and is capable of opening and rotating the tip bit 11 in the extending direction and closing it in the direction of the center pipe 13. In addition, rotating excavation blade 1
The base end side of 2 is connected to a slider 19 via a link 18. The slider 19 is fitted onto the outer periphery of the center pipe 13 so as to be movable up and down, and is connected to the lower end of the rod 20a of the hydraulic cylinder 200. A base end of the hydraulic cylinder 20 is connected to a bracket 13c of the center pipe 13. Therefore, the rod 2 of the hydraulic cylinder 2o
The slider 19 moves up and down due to the expansion and contraction of 0a, the distance of the link 18 from the center of the center pipe 13 changes, and the rotary excavation blade 12 opens and closes.

Further, a hydraulic cylinder 16 opens and closes the expanded bottom wing 10.

The hydraulic cylinder 2o that opens and closes the rotary excavation blade 12 is driven by, for example, a hydraulic circuit shown in FIG.

That is, the oil discharged from the hydraulic pump 21 is transferred to the directional control valve 22° through a pipe 23a disposed on the side of the hydraulic hose 6, drill pipe 8, and center pipe 13 shown in FIG.

23b to the rod side 16b or bottom side 16c of the hydraulic cylinder 16.
The rod 16a of No. 6 is expanded and contracted. In addition, the hydraulic pump 21
The oil discharged from the directional control valve 22, hydraulic hose 6, and piping 2
3a, 23b and automatic switching valve 24. Piping 25a,
25b to the rod side 20b or bottom side 20c of the hydraulic cylinder 20.
The rod 20a of ° is expanded and contracted. A roller 26 is attached to the automatic switching valve 24, and a cam 27 that contacts the roller 26 is attached to the lower end of the rod 16a of the hydraulic cylinder 16. When the hydraulic cylinder 16 reaches its maximum stroke, the roller 26 Pocket part 2 of cam 27
7a, and the automatic switching valve 24 is adapted to be switched by a spring 28. In addition, the piping 25b connecting the automatic switching valve 24 and the bore side 20c of the hydraulic cylinder 20 is provided with an operating check valve 29 for self-holding. 32 is a check valve; 33 is an on-off valve that cuts off the circuit to the hydraulic cylinder 2°; 34 and 35 are on-off valves for independently operating the hydraulic cylinder 20; on-off valves 33 and 34 are normally open; The on-off valve 35 is normally closed.

The hydraulic pump 21, the directional control valve 22 and the relief valve 30,31 are incorporated into the hydraulic unit 5 of FIG.

Next, the operation of this embodiment will be explained.

At the beginning of excavation, the bottom expansion bit 9 is set with each bottom expansion blade lO closed.
The excavated earth and sand etc. and muddy water are sucked up to the ground together through a center pipe 13, a drill pipe 8, a kelly bar 7, a swivel joint 4 and a suction hose 3 and discharged by operating a suction pump 1. Next, after excavating to a predetermined depth, the hydraulic pump 21 shown in FIG. 3 is operated, and the automatic switching valve 24 is switched to the (c) position by a cam mechanism in the state where the directional switching valve 22 is switched to the (a) position. I'm awake. Pressure oil from the hydraulic pump 2I is supplied to the rod side 16b of the hydraulic cylinder 16 through the pipe 23a, and the rod 16a rises as shown by arrow a, and the slider 15 shown in FIG. R10 is expanded in diameter via link 14. During this time, the pressure oil on the bore side 16c of the hydraulic cylinder 16 is transferred to the automatic switching valve 24.
, and is returned through the pipe 23b. Further, pressure oil from the hydraulic pump 2I enters the rod side 20b of the hydraulic cylinder 20, but does not operate because the bore side 20c is blocked.

Once the bottom has been expanded a little with the bottom expanding blade 10 open, the directional switching valve 22 is switched to the (b) position, and the pressure oil from the hydraulic pump 21 is passed through the pipe 23b and the automatic switching valve 24 to the bore side 16c of the hydraulic cylinder 16. The feed rod 16a is lowered in the direction of the arrow to close the expanded bottom R1o. Hydraulic cylinder 16
When the roller 26 reaches its maximum stroke, the roller 26 falls into the pocket portion 27a of the cam 27, and the automatic switching valve 24 is switched to the (d) position by the spring 28. As a result, the pressure oil is transferred to the pipe 23b,
It enters the bore side 20c of the hydraulic cylinder 20 through the automatic switching valve 24, piping 25b, and operating check valve 29,
The rod 20a is lowered, the slider I9 is lowered, and the rotating excavation blade L2 is rotated about the pin 17 in the direction in which the tip bit 11 extends via the link 18, as shown in FIG. When the rotary excavation blade 12 rotates to a position where it is flush with the excavation surface of the tip bit 11, the hydraulic cylinder 200 rod 20a hits a stopper (not shown) and stops. In this state, the entire bottom-expanding bit 9 is lowered, and vertical excavation is performed using the tip bit 11 and the rotary excavation blade I2. In other words, Fig. 4 (b
) Excavate the vertical rise of the bottom expansion section shown in ). At this time, the operator check valve 29 is activated by the rotary excavation blade 1 due to the excavation reaction force.
2 from rotating toward the closing side.

When the excavation of the expanded bottom portion is completed, the directional control valve 22 is switched to the (a) position to retract the rod 20a of the hydraulic cylinder 20, but before that, the relief valve 30 is adjusted to lower the pressure. This prevents the pressure cylinder 16 from operating if the pressure on the bore side 16c of the hydraulic cylinder 16 rises above the set pressure of the relief valve 31 when the hydraulic cylinder 20 reaches the end of its stroke and the pressure inside the pipe increases. This is to do so. The set pressure ratio of the relief valves 30 and 31 is:
It is determined by the area ratio between the bore side 16c and the rod side 16b of the hydraulic cylinder 16.

As described above, according to this embodiment, the vertical upright excavation of the expanded bottom part is performed using the tip bit 11 and the rotary excavation R12, thereby improving the excavation efficiency and solving the problem of insufficient rigidity with respect to excavation torque. can. In addition, the wide-bottomed wing lO
A switching valve 24 for switching the supply of pressure oil to the hydraulic cylinder 20 is provided between the hydraulic cylinder 16 that opens and closes and the hydraulic cylinder 20 that opens and closes the rotary excavation 'R12.
4 is provided on the rod 16a of the hydraulic cylinder 16.
Since the hydraulic piping can be switched from the ground to the bottom expanding bit 9 by two, the piping structure can be simplified. Furthermore, by closing the on-off valve 33 in the hydraulic circuit, only the hydraulic cylinder 16 can be operated, and normal bottom-expanding excavation is also possible.
By closing the on-off valve 35, it is also possible to operate only the hydraulic cylinder 20, and in this case, bottom widening excavation of an arbitrary shape can be performed.

〔Effect of the invention〕

According to the present invention, since the vertical upright excavation of the expanded bottom part is performed using the rotary excavation blade with the tip bit, the excavation efficiency can be improved compared to the case where excavation is performed with the expanded bottom blade, and the rigidity against the excavation torque is insufficient. Problems such as this can be resolved.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is a side view of a bottom-expanding excavator according to the present invention, and FIG. 2 is a side view of a bottom-expanding excavator according to the present invention, and FIG. 3 is a hydraulic circuit diagram of the bottom-expanding excavator, and FIG. 4 is an explanatory diagram showing the shape of the hole for the bottom-expanding pile. 8... Drill pipe, 9... Bottom expansion bit, 10...
- Expanded bottom wing, 11...Tip bit, 12...Rotating drilling wing, 13...Center pipe, 14.18...Link, 15.19...Slider, 16, 20...Hydraulic cylinder , 16a, 20a...rod, 17...
·pin.

Claims (1)

[Claims] 1. A bottom-expanding excavator that attaches a bottom-expanding bit to the lower end of a drill pipe and rotates the bottom-expanding bit with the drill pipe to drill a hole for installing a bottom-expanding pile, and the bottom-expanding bit is connected to the drill pipe with a pin to open and close. Possible multiple expansion wings,
Rotary drilling includes a tip bit fixed to the lower end of the drill pipe, and pins connected to both ends of the tip bit, allowing the tip bit to open and rotate in the extending direction and close in the drill pipe direction. A hydraulic cylinder that is attached to a drill pipe and opens and closes the bottom-expanding blade, and a hydraulic cylinder that opens and closes the rotary drilling blade, and the bottom-expanding blade and the rotating drilling blade can be opened and closed separately. A bottom-expanding excavator characterized by being configured as follows.