JPH0235837B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a reverse server which has a rotary table and has a bottom-expanding drilling tool attached to the lower part of a rotary drive shaft such as a drill pipe, the amount of which is set by a hydraulic cylinder. The present invention relates to a detection device for detecting the amount of bottom expansion of the bottom expansion digging tool in an excavator such as a curation drill.

(Prior art) In a reverse circulation drill, a drilling tool attached to the lower part of a rotary drive shaft is inserted into an engaging hole provided in a rotating part of a ground-based rotary table, and a kely bar is inserted into the engaging hole, and a drilling tool is inserted into the kely bar to form a drilling hole. Connecting a number of rotary drive shafts according to the depth, attaching a digging tool for digging to the lower end of the rotary drive shaft, and rotating the digging tool by the rotary table via the Kerry bar and the rotary drive shaft, In addition, excavation is carried out while sucking up the excavated soil along with water using a suction pump installed on the ground.At the final stage of excavation, a bottom-expanding tool is attached to the lower end of the rotary drive shaft, which can change the amount of bottom expansion using a hydraulic cylinder. When excavating a bottom widening section, it is necessary to continuously and reliably grasp the amount of bottom widening on the ground during excavation.

When detecting the amount of bottom expansion, it has conventionally been a common practice to convert the stroke of the hydraulic cylinder into an electrical signal using a potentiometer, and to extract the signal from the potentiometer to the ground via a cable. Electrical signals are taken out from the rotating body (drill string) via a slip ring inside the cable reel, which is wound onto a horizontal cable reel attached to the outer circumference of a rotating body such as a Kerryba, but this conventional structure according to,
In order to install a cable reel around the outer circumference of the drill string, the drum becomes larger and the minimum height of the swivel joint becomes higher (approximately 1m), so the distance from the water level in the casing fitted in the drill hole to the swivel joint becomes large. This increases the height, which makes it difficult for the suction pump required for a reverse circulation drill to suck up air, resulting in a problem that the reverse suction and vacuum efficiency decrease.

In addition, the cable is always wound around the cable reel, and if the swivel joint is disconnected during a setup change, the cable must be moved together with the cable reel, which may cause the cable to get in the way and cause the cable to break. .

In addition, if the cable reel is relocated so that it is located above the swivel joint position, the rotating part of the swivel joint should be moved around the rotating part of the swivel joint in order to wind the cable that rotates with the drill string onto the reel. have to pass,
Cable handling becomes difficult. That is, a pressure-resistant relay connector with a small outer diameter is required to pass through the rotating part, and the swivel joint itself is also of a special type and has a large outer diameter.

(Object of the Invention) In view of the above-mentioned points, the present invention eliminates the need for a horizontal cable reel and a rotating joint that electrically connect the rotating part and the non-rotating part, thereby simplifying the structure and extending the service life. The present invention aims to provide a bottom expansion amount detection device for a bottom expansion excavation tool for cast-in-place piles that can achieve the following.

(Structure of the Invention) The bottom expansion amount detection device of the bottom expansion excavation tool of the present invention is capable of transmitting and receiving electric signals between a rotating part and a non-rotating part using radio waves. That is, the present invention
In an excavator that has a rotary table and has a bottom-expanding tool attached to the lower part of a rotary drive shaft in which the amount of bottom-expanding is set by a hydraulic cylinder, the bottom-expanding tool has a bottom-expanding tool that has a bottom-expanding tool that has a bottom-expanding amount set by a hydraulic cylinder at the bottom of a rotary drive shaft. A potentiometer is installed to convert the stroke or the rotation angle of the blade of the bottom-expanding tool into an electrical signal, while a cable connected to the potentiometer and guided by a rotary drive shaft is wound around the rotating part of the rotary table. and a telemeter transmitter that transmits, in the form of radio waves, an electrical signal corresponding to the stroke of the hydraulic cylinder or the rotation angle of the bottom-expanding tool, which is detected by the potentiometer and sent via the cable; The telemeter transmitter and the power supply for the potentiometer are installed to construct one system with the power supply, the telemeter transmitter, the cable, and the potentiometer, and the telemeter is installed on the excavator or on the ground. It is characterized in that it is equipped with a telemeter receiver that receives radio wave signals from a transmitter.

(Function) In the present invention, the stroke of the bottom-expanding hydraulic cylinder of the bottom-expanding excavation tool, that is, the amount of bottom expansion is converted into an electric signal by a displacement detector, and the electric signal is guided to the rotation drive shaft, and The data is sent to a telemeter transmitter via a cable wound around a cable reel installed on the rotating part of the excavator, and the telemeter transmitter transmits the amount of bottom expansion in the form of radio waves to a telemeter receiver installed on the excavator or on the ground. to receive the radio signal. That is, the telemeter transmitter rotates together with the drill string, and the bottom expansion amount signal of the bottom expansion drilling tool transmitted from the telemeter transmitter in the form of radio waves is received by the stationary telemeter receiver. There is no need to provide a rotation joint for transmitting and receiving signals between the two.

(Example) An example of the present invention will be described below with reference to the drawings.
FIG. 1 shows the entirety of a reverse circulation drill equipped with a bottom expansion amount detection device for a bottom expansion drilling tool according to the present invention. Joint 2
A hydraulic winch 20 that moves the following drill string up and down, a depth gauge 21 that detects the depth of a drilling hole in conjunction with the hydraulic winch 20, and an electric suction hose 23 that supports a suction hose 23 that is connected to a suction pump 22. Equipped with 24 winches. The swivel joint 2 is a rotary joint that serves to connect the suction hose 23 and the kely bar 4, and through which muddy water passes. A horizontal section 2a is provided in the section. 3 is a hydraulic cylinder 3 of the bottom-expanding excavation tool 12, which will be described later.
Hydraulic piping 42 that supplies hydraulic oil to 5a and 35b
(See Figure 2) and the hydraulic piping on the hydraulic power source side (not shown).
This is a hydraulic joint that connects the pipes, and muddy water passes through it.

The Kelly bar 4 has a rectangular cross section as shown in FIG. 2, and has a rotary table 8 installed on the base 25.
The Kelly bar 4 is rotated by fitting it into a rectangular through hole 8b provided in the rotating part 8a so that it can move up and down, and rotating the rotating part 8a by the driving hydraulic motor 26 of the rotating table 8 (see FIG. 3). The rotary drive shaft 9 connected to the Kelly bar 4 and the bottom-expanding excavation tool 12 are configured to be rotated. 10 is a stabilizer that prevents the borehole from bending.

As shown in FIG.
8 and multiple excavation tool mounting stands 3.
0a and 30b are attached so as to be tiltable around pins 29a and 29b, respectively, and the excavator mounting base 3
Tip drilling tools 31a and 31 are installed at 0a and 30b, respectively.
Attach b. On the other hand, a slide block 32 is fitted into the main body 27 so as to be vertically movable, and the slide block 32 connects the tube to pins 34a and 3, respectively.
The slide block 32 is connected to the piston rods of opening/closing hydraulic cylinders 35a, 35b connected to the main body 27 by pins 33a, 33b, respectively, and the slide block 32 is connected to the excavator mounting bases 30a, 33b, respectively.
30b, rods 36a and 36b, respectively.
and pins 37a, 38a, 37b, at both ends thereof.
38b. With this configuration,
By expanding and contracting the opening/closing hydraulic cylinders 35a and 35b, the angle of the excavator mounting bases 30a and 30b relative to the main body 27 can be changed within a range of 90 degrees or less.

The main body 27 also includes an opening/closing hydraulic cylinder 35.
A potentiometer 11 is installed as a displacement detector for detecting the stroke of the hydraulic cylinder due to the operation of actuators a and 35b or the rotation angle of the blade of the bottom-expanding excavator 12 that corresponds 1:1 to the stroke. In the example, the tip of a wire 40 wound around a drum of a sealed potentiometer is connected to the slide block 32, and as the slide block 32 moves up and down, the drum rotates to adjust the position of the slide block 32. That is, it is configured such that the amount of expansion and contraction of the opening/closing hydraulic cylinders 35a, 35b is converted into voltage.

The cable 16 connected to the potentiometer 11 is guided by a fixture 41 to the rotary drive shaft 9, as shown in FIG. Opening 1
9, and is wound onto a cable reel 6 fixed to the rotating part 8a via a guide roller 17. Reference numeral 13 denotes a telemeter transmitter fixed on the rotating part 8a. A power supply (battery) is built in the telemeter transmitter 13, and the power is supplied through a slip ring (not shown) provided on the cable reel 6. A voltage signal from the potentiometer is received, and an FM signal corresponding to the magnitude of the voltage signal is transmitted from the antenna 15. Note that the transmission frequency in this case is selected to be a frequency that is not easily affected by external interference radio waves.

Reference numeral 14 denotes a telemeter receiver which is installed on a stationary part of the reverse circulation drill other than the rotating part 8a or on the ground and receives radio waves from the telemeter transmitter 13, and a receiving antenna 15 of the telemeter receiver 14. A plurality of '' are provided so that stable reception can be achieved even if obstacles such as the Kelly bar 4 and the cable reel 6 are interposed between the transmitting side and the receiving side as the rotating part 8a rotates.
Signals from each antenna 15' are input to the telemeter receiver 14 via a distributor 18.

In this configuration, the enlarged bottom portion 50a of the excavation hole 50
When drilling, the hydraulic winch 20 is operated in the direction in which the drill string descends, and the rotating part 8a of the rotary table 8 is rotated by the hydraulic motor 26 to rotate the drill string.
By gradually extending the hydraulic cylinders 35a, 35b of the bottom-expanding excavator 12, the excavator mounting bases 30a, 30b of the bottom-expanding excavator 12 change from the position and attitude shown by the imaginary line in FIG. 4 to the position and attitude shown by the solid line. Excavate as desired.

In this case, the excavation depth is detected by a depth gauge 21 that is linked to a hydraulic winch 20.

In addition, in the potentiometer 11, the drum of the potentiometer 11 rotates in conjunction with the movement of the hydraulic cylinders 35a, 35b of the bottom-expanding tool 12, and a continuous bottom-expansion amount signal is sent to a telemeter transmitter via the cable 16. Send to 13th. The telemeter transmitter 13 transmits a bottom expansion amount signal in the form of FM radio waves,
The telemeter receiver 14 receives the radio signal.

The amount of bottom expansion received by the telemeter receiver 14 and the depth detected by the depth gauge 21 are displayed on an operation panel (not shown), and the operator monitors each value while operating the hydraulic winch 20 and the bottom expansion excavation tool. 1
While operating the two hydraulic cylinders 35a and 35b alternately, the expanded bottom portion 50a of the desired shape is excavated.

In the above embodiment, an example was shown in which the expanded bottom portion 50a is excavated while lowering the expanded bottom excavation tool 12, but the expanded bottom portion 50a does not have a cutter on the bottom surface, but has expanded bottom wings that can be opened and closed like a door. The present invention can also be applied to the case where a cutter is provided vertically at the tip of the side surface of the drill bit, and an enlarged bottom section is excavated without substantially lowering the drill string.

In this way, when the present invention is applied to a reverse circulation drill, it goes without saying that there is no need for a rotation joint for transmitting and receiving the bottom expansion amount signal, and there is no need for a conventional horizontal kale reel. Therefore, the minimum height of the swivel joint can be lowered, and the reverse suction and vacuum efficiency can be increased. Furthermore, the cost is low because the swivel joint is a standard type rather than a special type. In addition, since the cable and the cable are separated when the cable is disconnected (during setup), there is no risk of the cable being cut.

Furthermore, although the above explanation has focused on a reverse circulation drill, it can also be applied when the excavator is an earth drill with a bottom-expanding tool.
In this case as well, there is no need for a horizontal cable reel that is attached to the bottom of the Kerryver drive unit.
The structure is therefore simpler, the front frame can be made smaller, stability is improved, and a large bucket can be attached, making it possible to increase the soil removal height.

(Effects of the Invention) As explained above, according to the present invention, the conventional horizontal cable reel and the rotating joint for transmitting and receiving the bottom expansion amount signal are not required, and the swivel joint can be a standard type instead of a special type. Therefore, the configuration is simple and the cost is low. In addition, since the present invention uses wireless for transmitting and receiving signals, there is no signal disturbance due to changes in sliding contact resistance in the rotating joint over time, and a stable continuous signal can be obtained. It is possible to accurately grasp the shape of the pile, improve the shape accuracy of the pile, and facilitate automatic control of bottom-expanding excavation.

Furthermore, when the present invention is applied to a reverse circulation drill, the conventional horizontal cable reel is no longer necessary, so the minimum height of the swivel joint can be lowered, and the reverse suction and vacuum It can increase efficiency. Further, since the cable and the cable are separated when the cable is disconnected (during setup), there is no risk of the cable being cut.

Furthermore, when the present invention is applied to an earth drill, the horizontal cable reel attached to the bottom of the Kerry bar drive device is not required, so the configuration is simplified, the front frame can be made smaller, and stability is improved. In addition, it is possible to install a tall bucket, increasing the soil removal height.

[Brief explanation of drawings]

FIG. 1 is a side view of a reverse circulation drill showing an embodiment of the bottom expansion amount detection device according to the present invention, FIG. Front view of table section, 4th
The figure is a side view of the bottom-expanding excavation tool in this embodiment. 4...Keriba, 6...Cable reel, 8...
...Rotary table, 8a... Rotating unit, 9... Rotation drive shaft, 11... Potentiometer, 12... Expansion bit, 13... Telemeter transmitter, 14... Telemeter receiver, 15, 15'... antenna, 1
6...Cable, 20...Hydraulic winch, 21...
...depth gauge, 35a, 35b...hydraulic cylinder.

Claims (1)

[Claims] 1. In an excavator that has a rotary table and has a bottom-expanding excavating tool attached to the lower part of a rotary drive shaft in which the amount of bottom-expanding is set by a hydraulic cylinder, the bottom-expanding excavator has a hydraulic cylinder that is attached to the bottom-expanding tool in accordance with the operation of the hydraulic cylinder. A potentiometer is installed to convert the stroke of the bottom drilling tool or the rotation angle of the blade of the bottom-expanding tool into an electrical signal, while a cable connected to the potentiometer and guided by the rotary drive shaft is attached to the rotating part of the rotary table. a cable reel to be wound up; a telemeter transmitter that transmits in the form of radio waves an electric signal detected by the potentiometer and sent via the cable that corresponds to the stroke of the hydraulic cylinder or the rotation angle of the bottom-expanding tool; , the telemeter transmitter and the power source of the potentiometer are installed, and the power source, the telemeter transmitter, the cable and the potentiometer constitute one system, and the excavator or the ground is equipped with the power source of the potentiometer. 1. A bottom expansion amount detection device for a bottom expansion excavation tool for driving-in-place piles, characterized in that it is provided with a telemeter receiver that receives radio signals from a telemeter transmitter.