JPH01103272A - Air pressure type rock drill - Google Patents

Abstract

PURPOSE: To provide great destruction force and to ease a shock transmitted to a main body in an impact application time by connecting an accumulator communicated with a small cross section area part formed in the rear part of a piston, which can be moved forward/backward freely in a cylinder, to an intake pipe in a compressed air source via a check valve. CONSTITUTION: Based on a cross section area difference between the front and rear cross sections of a piston 3, which is moved forward/backward in a piston and provided with a small cross section area part in the rear part, the piston 3 is moved backward and pressurized air is accumulated in an accumulator 10. Then, a three-way selector valve 5 is opened when a stroke end of the piston 3 is detected, and air in front of the piston 3 is discharged from an air intake/exhaust port 6. Simultaneously, the piston 3 is suddenly advanced by means of air pressure accumulated in the accumulator 10 so as to hit a bit 1, and a hard rock-bed 13 is destroyed by means of the bit 1 with great destruction force. When the bit 1 is advanced according to this destruction of the rock-bed 13, the air intake/exhaust port 6 is closed, and empty hitting can be prevented automatically. A reaction force after hitting is absorbed by the air pressure connected to the air pressure accumulator 10. Consequently, a shock in the rock drill main body can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pneumatic rock drill used primarily for excavating small-section rock tunnels and the like.

[Prior art]

In recent years, excavation works such as small-section rock tunnels have been increasing in Japan, but the use of hydraulic rock drills to crush the rock in such relatively small-diameter shield construction is difficult because of the hydraulic pressure. Since the unit cannot be installed at the tip, it requires long hydraulic piping, which is impractical, and in conventional pneumatic rock drills, the impacting body is directly hit with compressed air from its compressed air source, resulting in a crushing force. There is no effective excavation method for crushing hard rock, other than blasting, and currently we rely on manual excavation using concrete breaker.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned conventional problems, and aims to provide a small pneumatic rock drill that can obtain a large destructive force even though it is a pneumatic type. .

[Structure of the invention]

The pneumatic rock drill of the present invention for achieving the above objects includes:
A bit, which is a striking body, is inserted into the tip so that it can move back and forth, and a piston with a small cross-sectional area formed at the rear is inserted coaxially at the rear of the bit, and a piston is inserted so that it can move back and forth. An air supply port is provided which is connected to the intake pipe and exhaust port of the air source via a three-way switching valve, and which opens and closes a communication passage with the front of the piston in the cylinder depending on the forward and backward movement position of the bit. It is constructed by disposing a pressure accumulator that is supplied with air from the intake pipe of the air source via an air supply check valve and communicates with a small cross-sectional area of the piston in the cylinder.

In the pneumatic rock drill with the above configuration, the piston moves backward and the pressurized air is stored in the pressure accumulator by the difference in cross-sectional area between the front and rear of the piston, which has a small cross-sectional area at the rear that moves forward and backward inside the cylinder. By operating the three-way switching valve, the air in front of the piston is exhausted from the intake and exhaust port, and the piston moves forward rapidly to strike the bit, so unlike conventional pneumatic rock drills, the bit can be driven using only the power of a compressed air source. In addition to being able to obtain stronger rock destruction power than those using the striking method,
The reaction force after the impact is also absorbed by the air pressure communicated with the pressure accumulator, and the impact on the rock drill body is alleviated.

〔Example〕

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a side sectional view showing the state of a pneumatic rock drill in an embodiment of the present invention during the air supply process, and FIG. FIG. 3 is a side cross-sectional view showing the state during the striking process, and FIG. 3 is a side view of the overall arrangement of the pneumatic rock drill shown in FIG. 1.

First, as shown in Figures 1 and 2,
A bit 1, which is an impacting body for crushing, is fitted so as to be movable back and forth, and a piston 3, which has a diameter d smaller at the rear than the diameter at the front, is fitted coaxially at the rear of the bit 1 so as to be movable back and forth. The cylinder 2 is provided with an air supply/exhaust port 6 connected to an intake pipe 8 of a compressed air source such as a compressor 11 and an exhaust port 7 via a three-way switching valve 5. A communication passage 12 formed in this bit l so as to communicate with the front of the piston 3 in the bit l.
is arranged to be opened or closed depending on the forward or backward movement position of this bit l.

Next, a pressure accumulator 10 is provided, which is supplied with air from the intake pipe 8 through an air supply check valve '9. It's becoming easier to communicate.

In addition, the above-mentioned bit 1 moves back and forth to the bedrock 13.
The cylinder 2 is stopped by a stopper bolt 4 provided on the cylinder 2 side.

Further, the above pneumatic rock drill is supported and mounted in a shield 14 with a holder 15 as shown in FIG.
It is designed to be able to move up and down as needed using the point as a fulcrum as shown by arrow R.

Next, the operation of the pneumatic rock drill having the above configuration will be explained. First, in the preparation process, compressed air of, for example, about 7 kg/cj is supplied to the pressure accumulator 10 via the air supply check valve 9. The air pressure causes the piston 3 and the bit 1 to move forward in the cylinder 2, but the forward movement of the bit 1 closes the air supply/exhaust port 6 to the communication path 12.

Next, in a pressing step, when the rock drill body is pressed together with the cylinder 2 against the striking surface of the rock 13, the bit 1 moves backward and the air supply/exhaust port is opened to the communication path 12.

Furthermore, in the air supply process shown in FIG. 1, air supply is started by switching the three-way switching valve 5, and due to the difference in the cross-sectional area of the front and rear pressure receiving surfaces of the piston 3, the piston 3 moves backward and 7 kg is transferred to the pressure accumulator 10. /
The air pressurized above - is accumulated and balanced near the stroke end of the piston 3.

Next, in the striking process shown in Fig. 2, the three-way switching valve 5 is automatically opened upon detection of the end of the stroke of the piston 3, and the accumulated air pressure causes the piston 3 to rapidly move forward and strike the bit 1. , the batting stroke at that time is indicated by S.

If the striking surface of the rock 13 is destroyed as described above, the supply/exhaust port 6 is closed by the advance of the bit 1, so that dry striking is automatically prevented.

Incidentally, since the reaction force after the impact is also absorbed by the air pressure communicated with the pressure accumulator 10, the impact on the rock drilling machine body is alleviated.

〔Effect of the invention〕

As explained above, although the pneumatic rock drill of the present invention is pneumatic, it uses stored air to hit rock with the bit over a long stroke, so it is different from conventional pneumatic rock drills. Compared to conventional drop hammers, it has the advantage of being able to obtain greater destructive power, powerfully crushing even hard rock, making it easier to remove scraps afterwards, and being able to strike in all directions, unlike conventional drop hammers.

In addition, the piston that hits the bit is held by air pressure that communicates with the pressure storage chamber, so it absorbs the rebound when hitting, reducing the impact on the rock drill body, and automatically prevents the bit from hitting blankly when hitting. This has the advantage of allowing safe work.

The pneumatic rock drill of the present invention can be effectively applied mainly to excavating small-section rock tunnels and the like.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing the state of a pneumatic rock drill according to an embodiment of the present invention during the air supply process, FIG. 2 is a side sectional view showing the state during the striking process of FIG. 1, and FIG. This figure is a side view of the overall arrangement of the pneumatic rock drill shown in FIG. 1. 1... Bit, 2... Cylinder, 3... Piston, 5... Three-way switching valve, 6... Supply/exhaust port, 7...
... Exhaust port, 8... Intake pipe, 9... Air supply check valve, 10... Pressure accumulator, 11... Compressor, 12...
...Communication path, a...Small cross-sectional area.

Claims (1)

[Claims] A bit is attached to the tip, and a piston with a small cross-sectional area formed at the rear is fitted coaxially to the rear of the cylinder so that it can move forward and backward, and a three-way switching valve is attached to the intake pipe and exhaust port of the compressed air source. and an air supply/exhaust port connected to the bit through a check valve, and a communication path with the front of the piston in the cylinder is opened and closed depending on the forward and backward movement position of the bit, and air is supplied from the intake pipe via a check valve, A pneumatic rock drill is provided with a pressure accumulator that communicates with the small cross-sectional area of the piston in the cylinder.