JPS6245389B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pneumatic impact type drilling device, and more particularly to a pneumatic impact type drilling device in which a piston is moved up and down by pressurized air, and the impact energy of the piston repeatedly applies impact vibration to a drill bit. Regarding drilling equipment.

Conventionally, many pneumatic impact drills that use air have been developed, but most of them were developed for relatively small diameter and shallow drilling, and they are not necessarily strong enough for hard rock, large diameter, and deep drilling. I was not satisfied with the efficiency. For example, the applicant claims that
The specification of No. 35356 describes a cylindrical casing connected to a drill pipe at the upper part and supporting a drill bit slidably in the axial direction at the lower part, and a pressurized air supply source formed integrally with the casing within the casing. a cylindrical flow pipe in which an air supply communication passage communicating with the exhaust passage and an exhaust communication passage communicating with the exhaust passage are arranged in parallel in the axial direction;
a piston in which the flow path pipe is inserted into a through hole formed in the center, the piston is arranged to be slidable in the axial direction within the casing, and the piston hits a drill bit with its lower end;
A pressurizing passage is formed in the casing in the axial direction between the piston and the inner surface of the casing and communicates with the air supply passage through a communication hole formed in the piston in the radial direction, and a pressurizing passage is formed in the cylinder below the piston. A first pressure chamber is formed above the piston in the casing and is pressurized as the piston rises to urge the piston downward. We proposed a pneumatic percussion type drilling rig having a chamber and a chamber.

This pneumatic impact type excavation rig has the advantage of being able to obtain a larger piston stroke and a wider pressure receiving area than conventional excavation rigs. However, in order to further improve the excavation efficiency and apply it to deep excavation, it is necessary to increase the air pressure to more than twice that of the conventional one. Increasing the price has the following disadvantages:
In other words, the drilling equipment described in Japanese Patent Publication No. 57-35356 is
Since pressurized air is supplied from the central flow pipe to the pressurized passage on the outside of the piston, a radial air communication hole is formed in the piston that receives the most impact force, making it easy for stress concentration to occur structurally. Cannot withstand high pressure air. Furthermore, the center flow pipe also has a strength problem because the air supply communication passage and the exhaust communication passage are arranged side by side, and a groove is formed to connect the air supply communication passage and the communication hole of the piston.

The present invention has been made in view of the above circumstances, and an object of the present invention is to propose a pneumatic percussion excavation device that has a simple piston structure and can withstand high pressure air. In the present invention, pressurized air is supplied to the first pressure chamber below the piston from the outside of the piston, and pressurized air is supplied from the inside of the piston to the second pressure chamber above the piston through the supply and exhaust grooves of the flow pipe. It is characterized by being supplied.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the pneumatic percussion excavator according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the casing 10 is formed into a substantially cylindrical shape, and the upper part thereof is connected to a not-shown tunnel. Inside the upper end of the casing 10 is an air supply passage 12.
This air supply passage 12 communicates with a pressure air supply source (not shown), and is supplied with pressure air.
As shown in FIG. 1, a small-diameter air supply passage 14 is formed below the air supply passage 12, and an air supply passage 16 having a ring-shaped cross section is further formed below the air supply passage 14. . Communication between the air supply passage 14 and the air supply passage 16 is interrupted by a check valve 18 . The check valve 18 is slidably disposed within a cylindrical portion 20 that is integrally formed with the casing 10.
A spring 22 disposed within the valve seat 24
is biased towards. Therefore, the check valve 18 is designed not to open unless pressurized air sufficient to overcome the biasing force of the spring 22 is supplied from above, and this prevents water in the borehole and excavation slime remaining in the borehole. etc. to prevent backflow.

The air supply passage 16 communicates with a lower air supply passage 28 via a communication hole 26. The air supply passage 28 communicates with an air supply passage 34 formed in the base 32 of the flow pipe 30. Casing 10 and base 32 of flow pipe 30
A cylinder 35 is disposed between and extends downward beyond the base 32.
The flow pipe 30 extends downward at the center of the cylinder 35. The piston 36 is slidably disposed within the cylinder 35 and the casing 10, and the flow pipe 30 is fitted into a through hole 38 formed at the center of the piston 36. A first pressure chamber 40 is formed below the piston 36, and a second pressure chamber 42 is formed above the piston 36.

The air supply passage 34 of the base 32 communicates with an annular groove 48 formed on the inner surface of the casing 10 via a communication hole 44 formed in the radial direction of the base 32 and a hole 46 formed in the cylinder 35. Annular groove 4
8 communicates with an annular groove 52 formed in the outer circumferential surface of the piston 36 via a passage 50 between the casing 10 and the cylinder 35 . The annular groove 52 is
Passage 54 between casing 10 and piston 36
It communicates with the first pressure chamber 40 via. Annular groove 4
8. The passage 50, the annular groove 52, and the passage 54 constitute a first pressurizing passage, and air (not shown) is supplied to the first pressure chamber 40 through this first pressurizing passage at the position of the piston 36 shown in FIG. Air is supplied from a pressure source.

A second pressurizing passage 56 is axially bored in the flow pipe 30 , and the upper end of the second pressurizing passage 56 opens to the air supply passage 34 , and the lower end opens to the flow pipe 30 through a port 58 . It is open on the outer circumferential surface. Further, on the outer peripheral surface of the flow pipe 30, vertical grooves 6 as supply/exhaust grooves are provided in the axial direction.
0 is formed, and the upper end of the vertical groove 60 is connected to the second pressure chamber 42.
It is open to A small diameter portion 62 is formed at the lower end of the flow pipe 30, as shown in FIGS. 1 and 2. Further, an annular groove 64 is formed in the inner peripheral surface of the through hole 38 of the piston 36. At the solid line position of the piston 36, the second pressure chamber 42 is communicated with the exhaust passage 65 of the piston 36 via the vertical groove 60 and the annular groove 64, but as the piston 36 rises, the second pressure chamber 42
8 opens into the annular groove 64, the second pressure passage 56
is connected to the second pressure chamber 4 via the annular groove 64 and the vertical groove 60.
2 is communicated with.

A center hole 66 is bored in the flow path pipe 30, the upper end of the center hole 66 is closed with a plug 68, and the center hole 66 is closed.
The lower end of 6 is opened and communicated with exhaust passage 65 .
When the plug 68 is removed, pressurized air is supplied from the center hole 66 to the exhaust passage 65, increasing the ability to remove excavated slime. By providing a restriction in the center hole 66 at the position of the plug 68, the amount of air flowing from the center hole 66 can be adjusted as appropriate.

A main body 76 of a bit 74 is supported by a spline connection 72 at the lower end 70 of the casing 10 so as to be slidable in the axial direction. Therefore, when the lower end surface of the piston 36 applies a striking force to the upper part 78 of the bit 74, the bit 74 moves downward in FIG. The stopper ring 80 is fixed to the lower end 70 of the casing 10 to prevent the bit 74 from coming off the lower end 70. Upper part 78 of bit 74
is provided with a pipe 82, and the upper part of the pipe 82 can be inserted into the exhaust passage 65. When the piston 36 rises and the pipe 82 comes off from the exhaust passage 65, the first pressure chamber 40 becomes depressurized. That is, pipe 8
2 determines the timing of depressurization of the first pressure chamber 40. Note that when the pipe 82 is fitted into the exhaust passage 65, the exhaust passage 65 is connected to the exhaust passage 8 of the bit body 76.
4 is connected. The air used to operate the piston 36 is discharged to the exhaust passages 65 and 84, and this air is discharged to the outside to clean the tips of the bit teeth, blow up slime, etc. to the ground, and remove the slime in the excavation hole. .

The operation of the embodiment according to the present invention configured as described above is as follows. First, the piston 36
In the position shown, pressurized air is directed into the first pressure chamber 40 through the first pressure passages, annular groove 48, passage 50, annular groove 52, passage 54, and urges the piston 36 upwardly. In this state, the second pressure chamber 42
is in communication with the exhaust passage 65 via the vertical groove 60 and the annular groove 64, and is in a reduced pressure state. Therefore, the piston 36
rises without being resisted by the air in the second pressure chamber. When the piston 36 rises to the position shown in FIG. pressurization is stopped. Even if the supply of pressurized air to the first pressure chamber 40 is stopped, the piston 36 rises for a while due to the expansion of the air in the first pressure chamber 40 and the inertia of the piston 36.

When the piston 36 rises to the position shown in FIG. 4, the upper end of the pipe 82 opens in the first pressure chamber 40, and the first pressure chamber 40 is communicated with the exhaust passage 84 and the pressure is reduced. On the other hand, in the piston 36 shown in FIG. 4, the port 58 of the second pressure passage 56 is connected to the annular groove 64.
A second pressure passage 56 is opened to the second pressure chamber 42 .
Pressurized air is supplied through the annular groove 64 and the vertical groove 60. As a result, the pressure of the second pressure chamber 42 acts on the upper surface of the piston 36, urging the piston 36 downward. This causes the piston 36 to descend and strike the upper part of the bit body 76 at the position shown in FIG. The first pressure chamber 40 is disconnected from the exhaust passage by fitting the pipe 82 into the exhaust passage 65, and the first pressure chamber 40 is again pressurized as described above. In addition, the second pressure chamber 42 has a vertical groove 60 and an annular groove 64 immediately before the end of the downward stroke of the piston 36.
It communicates with the exhaust passage 65 via the exhaust passage 65 and is depressurized.

Thereafter, while repeating the above-described steps, a striking force is applied to the bit 74 by the piston 36, and a rotational force is applied to the bit 74 by the casing 10, thereby digging.

In the embodiment described above, the pipe 82 was fixed to the upper part 78 of the bit 74, and the communication between the first pressure chamber 40 and the exhaust passage 84 was established and interrupted via this pipe 82, but the present invention is not limited to this. isn't it. That is, in the embodiment shown in FIG. 5, a small diameter portion 88 is formed at the tip of the piston 36, and a ring 90 into which the small diameter portion 88 fits is provided in place of the pipe 82, so that the ring 90 has the function of the pipe 82. It is shown. The first pressure chamber 40 is located at the small diameter portion 8 of the piston 36.
8 fits into and leaves the ring 90, communication with the exhaust passage 84 is interrupted. In the embodiment shown in FIG. 5, since the ring 90 is constructed separately from the bit that receives the impact, it is stronger than the pipe 82 in FIG. 1 and can withstand the use of high-pressure air.

As explained above, according to the pneumatic percussion excavator according to the present invention, pressurized air is supplied to the first pressure chamber below the piston from the outside of the piston, and to the second pressure chamber above the piston from the inside of the piston. Since pressurized air is supplied from the piston through the flow pipe, the structure of the piston is less prone to stress concentration and can withstand the use of high pressure air, improving excavation efficiency.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of an embodiment according to the present invention, FIG. 2 is a sectional view taken along the upper line in FIG. 1, and FIGS. 3 and 4 are sectional views showing the operation of this embodiment.
FIG. 5 is a sectional view showing the structure of another embodiment according to the present invention. 10...Casing, 36...Piston, 30
...Flow path pipe, 40...First pressure chamber, 42...Second
Pressure chamber, 48, 52... Annular groove, 50, 54...
Passage, 56...Second pressure passage, 60...Vertical groove, 6
4...Annular groove, 74...Bit, 84...Exhaust passage.

Claims (1)

[Claims] 1. A cylindrical casing that supports a bit slidably in the axial direction at its tip and is connected to a bore pipe at its rear end;
A flow path tube is arranged in the axial direction in the center of the casing, and the flow path tube is fitted into a through hole formed in the center and is supported so as to be slidable in the axial direction within the casing. a first pressurizing passage formed between the striking piston, the inner surface of the casing and the outer circumferential surface of the piston and communicating with a pressurized air supply source; A second pressurizing passage communicating with a pressure air supply source, a supply/exhaust groove formed in the axial direction on the outer circumferential surface of the flow pipe, an annular groove formed on the inner circumferential surface of the through hole of the piston, and A first pressurizing passage is formed below the piston and communicates with the first pressurizing passage to urge the piston upward.
a pressure chamber, and a second pressure chamber formed above the piston in the casing and communicating with the second pressure passage via the annular groove and the supply/exhaust groove to urge the piston downward; The first pressure chamber communicates with the exhaust passage near the end of the piston's upward stroke and is depressurized, and the second pressure chamber communicates with the exhaust passage near the end of the piston's downward stroke via the supply/exhaust groove and an annular groove. A pneumatic percussion drilling rig characterized by communication and reduced pressure.