JPS59192472A - Hydraulic breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic breaker that can be used underwater.

Hydraulic breakers used for breaking rocks, etc., will generate abnormally high pressure when water enters the striking chamber, damaging the gasket and other parts. Therefore, when using the hydraulic breaker underwater, make sure that water does not enter from the outside. It is necessary to. For this reason, the conventional method of preventing water intrusion was to send air at a pressure higher than the surrounding water pressure into the striking chamber where the striking piston of the hydraulic breaker strikes the chisel. However, simply sending air into the striking chamber is not enough to prevent water from entering the striking chamber due to compressor failure, broken hoses, broken joints, operational errors, changes in air pressure, changes in water depth, dry striking, striking posture, etc. Penetration often leads to breakage and malfunction of the breaker, and until now, highly reliable hydraulic breakers for underwater use have not been available.

An object of the present invention is to eliminate the above-mentioned drawbacks of conventional hydraulic breakers and provide a highly reliable hydraulic breaker that can be safely used underwater.

The present invention aims to solve this problem by reducing the pressure in the striking chamber when the pressure in the striking chamber reaches its limit when water enters the striking chamber for some reason and abnormally high pressure is generated due to the incompressibility of water. The control valve that operates directly and controls the impact is switched to a state that pushes the impact piston in the direction away from the chisel.
・This was achieved by creating a hydraulic breaker with a built-in pilot switching valve.

According to the present invention, even if there is intrusion into the striking chamber, the pressure does not rise above a certain limit pressure, and damage to the packing portion adjacent to the striking chamber is prevented.

The details of the present invention will be explained with reference to embodiments shown in the drawings.

In FIG. 1, a striking piston 2 is reciprocatably guided in a cylinder 1 forming an intermediate casing.
A breaker lower casing 3 is fixed to the lower end of the breaker, and a cylinder force bar 4 forming the upper casing is fixed to the upper end.

) A chisel 5 is attached to the breaker lower casing 3 so as to be able to slide back and forth, but not to fall off. Inside the breaker lower casing 3, a striking chamber 6 is formed near the end on the cylinder 1 side. The striking chamber 6 is connected by a passage 7 to an air supply port 8 of the breaker lower casing 3, and furthermore, the striking chamber 6 is connected by a passage 9 to a pilot passage 10 formed in the cylinder 1. The pilot passage 10 is connected to a pilot switching valve 11 formed within the cylinder 1.

As shown in FIG. 2, the pilot switching valve 11 includes a short-circuit piston 12 as a pilot valve body, a sleeve 13 that is attached to the cylinder 1 and slides and guides the short-circuit piston 12.
A spring 14 is installed between the cylinder 1 and the short-circuit piston 12 and presses the short-circuit piston 12. A rod 15 is slidably guided in the sleeve 13 and can come into contact with the end of the short-circuit piston 12 opposite to the spring 14 . The rod 15 is arranged such that its end opposite the shorting piston 12 receives the pressure of the fluid in the passage 10 formed in the sleeve 13.

Depending on the difference between the fluid pressure in the passage 10, that is, the pressure in the striking chamber 6, and the force of the spring 14, the shorting piston 12 moves up and down in the figure. When the pressure in the striking chamber 6 exceeds a certain value, the short-circuit piston 12 moves to the upper blade operating position against the force of the spring 14, and when the pressure in the striking chamber 6 falls below a certain value, it moves under the spring 14. The shorting piston 12 is held in the lower waiting position shown in FIG.

The sleeve 13 can be constructed as a whole as one member, but in consideration of ease of assembly and workability, it can also be constructed as a separate body as appropriate, as shown in the figure.

The cylinder 1 includes a first conduit 16 that communicates with the interior of the sleeve 13 near the end of the sleeve 13 on the spring 14 side;
A second conduit 17 is formed in the sleeve 13 and communicates with the short-circuit piston 12 near the end opposite to the spring 14 , the first conduit 16 being connected to the cylinder hole in which the percussion piston 2 of the cylinder 1 is guided. It communicates with a return passage 19 via an annular groove 16' provided in 18. Note that the first guide path 16 is connected to the annular groove 1
6'' and can also be configured to be directly connected to the return path 19.
6 opens into an annular groove 17' provided in the cylinder bore 8, and is connected to a signal flow path 21 leading to a control valve 20 either directly or via an annular groove 17''.

When the short-circuit piston 12 is in the standby position (the state shown in FIG. 2), the short-circuit piston 12 blocks the space in the sleeve 13 that communicates with the first conduit 16 and the space that communicates with the second conduit 17. . When the short-circuiting piston 12 moves to the operating position, the first conduit 16 and the second conduit 17 communicate within the sleeve 13 .

A locking groove 22 is formed in the rod 15, and a locking device 23 is attached to the cylinder 1 so that it can be locked in the locking groove 22 when the rod 15 moves the short-circuit piston 12 to the operating position. The locking device 23 is the locking groove 2 of the rod 15.
A lock par 24 having a tip Mi that can be locked to a lock par 2; a bush 25 formed to slide and guide the lock par 24 and prevent it from falling off; and a bush 25 that is screwed onto the cylinder 1; and lock bar 2
4 toward the rod 15.

When the rod 15 pushes the short-circuiting piston 12 into the operating position, the locking bar 24 engages the locking groove 22 of the rod 15 under the action of the locking spring 26 and holds the rod in that position. When the locking member 24 is pulled, the engagement is released and the short-circuit pinuton 12 can return to the standby position.

The cylinder hole 18 of the cylinder 1 is divided into three fluid chambers by a first land 2a and a second land 2b formed in the striking piston 2. Sealing devices 27, 28 are provided at the upper and lower ends of the cylinder 1, respectively, for sealing the cylinder bore 18 from the outside.

A supply path 29 for supplying a working fluid, for example, hydraulic pressure, is formed in the cylinder 1 and the cylinder cover 4.1.
It is connected to the fluid chamber 38 at the lowest end in FIG.

The return path 19 of the working pressure opens into an intermediate fluid chamber 39 formed in FIG. 1 of the cylinder bore 18 and is connected to the low pressure accumulator 32.

Further, the supply path 29 is connected to a first port 33 of the control valve 20, and the return path 19 is connected to a second port 34 of the control valve 20.

An inlet 33 is connected to the control piston 35 as a valve body of the control valve 20.
A signal path 21 leading to the second conduit 17 of the pilot switching valve 11 connects to the signal port of the control valve 20 so as to actuate the fluid in a direction opposite to the fluid pressure from the control valve 20 .

A fluid chamber 40 at the upper end of the cylinder bore 18 in the drawing is connected by a conduit 36 to a stripe 3 port 37 of the control valve 20.

The structures of the control valve 20 and the pilot switching valve 11 are not limited to the example shown in the figure, and other structures may be used as long as they perform the same function.

The structure of the hydraulic breaker of the present invention can be expressed generally using abbreviations as shown in FIG. 3. In FIG. 3, parts corresponding to those in FIGS. 1 and 2 are given the same reference numerals as in FIGS. 1 and 2.

The operation of this device will be explained.

When high-pressure fluid, that is, high-pressure oil is supplied through the supply path 29 under the control of a control section (not shown), the fluid chamber 38 at the lower end
High pressure oil enters the cylinder cover 4, and the striking piston 2
It rises while compressing the gas, for example, nitrogen gas, in the gas chamber 41 formed therein. At this time, the control piston 35 of the control valve 20 is pushed to the left end in the figure by the action of fluid pressure from the first port 33 (the state shown in FIG. 1).

After the lifting of the striking piston 2, the second
The part where the guide path 17 and the signal path 21 are open is the supply path 2.
9, that is, from the middle fluid chamber 39 to the lower end fluid chamber 38, the pressure acting on the control piston 35 of the control valve 20 from the left side in the figure becomes large. , due to the difference in the pressure receiving area of the control piston, p
The control piston 35 moves to the right in the figure under the influence of fluid pressure from the signal path 21.

When the control piston 35 moves to the right, the third
The boat 37 communicates with the first port 33 and high pressure oil flows into the upper end fluid chamber. The impact piston 2 begins to move downward forcefully due to the effects of the pressure from the high-pressure oil flowing in and the pressure of the compressed gas in the gas chamber 41.

When the striking piston 2 descends and strikes the chisel 5, the signal path 21 is brought into communication with the return path 19 (the state shown in FIG. 1), and the pressure acting on the control piston 35 from each side in the figure is reduced. Therefore, the control piston 35 moves to the left in the figure and returns to its initial state.

By repeating the above steps, the striking piston 2 moves back and forth up and down, causing the chisel 5 to vibrate.

Since the internal volume of the striking chamber i changes due to the reciprocating movement of the striking piston 2, the pressure inside the striking chamber changes.

When used underwater, air is supplied to the striking chamber 6 through the passage 7, and the air pressure is maintained at a level slightly higher than the water pressure at the depth of water used to prevent water from entering.

If water enters for some reason, the reciprocating movement of the striking piston 2 will generate abnormally high pressure because water is incompressible.
This will damage the sealing device 28 and the like. However, in the present invention, abnormally high pressure due to water intrusion is guided into the passage 9 to the pilot flow passage 10 of the pilot switching valve 11.

When the pressure in the striking chamber 6 rises to a predetermined pressure, for example, a pressure preset by the spring 14, the short-circuit piston 12 moves, and the first conduit 16 and the second conduit 17, which have been cut off until now, are moved.
The signal path 21 for the control valve 20 is communicated with the return path 19. Therefore, since the control piston 35 of the control valve does not move while the percussion piston 2 is raised, the force for lowering the percussion piston 2 is maintained in a weak state, and the percussion piston 2 stops.

When the short-circuit piston 12 of the pilot switching valve 11 returns, the first conduit 16 and the second conduit 17 are cut off, returning to a normal state, and normal operation starts again.

According to the present invention, when abnormally high pressure is about to occur, the operation of the hydraulic breaker is completely stopped by the action of the pilot switching valve, so that damage can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an embodiment of the hydraulic breaker of the present invention, Fig. 2 is an enlarged sectional view of the pilot switching valve portion, and Fig. 3 schematically shows the hydraulic system of the hydraulic breaker of the present invention. It is an explanatory diagram. 1...Casing (cylinder) 2...Blow piston 3...Casing (breaker lower casing) 4...
・Casing (casing cover) 6...Blow chamber 7...Air pressure fitting means (passage) 10...Pilot channel 11...Pilot switching valve 12...Pilot valve body (short circuit piston) 20...・
Control valve 21... Signal flow path 35... Valve body (control piston) Fig. 3■ 311 20 2 "29:334 ゛29)
1-cho 731-1o j 6 '1 JP-A-59-192472 (5) ■Le Nawate

Claims (1)

[Claims] A chisel that is reciprocatably supported on a casing, a striking piston that is supported on the casing so as to be able to reciprocate along the same axis as the chisel with a stroke longer than the chisel, and a hydraulic system that drives the striking piston back and forth. and a means for pressurizing air into a striking chamber, which is a space formed at a position where the striking piston and the chisel abut, and a means for pressurizing air into the striking chamber, which is a space formed at a contact position between the striking piston and the chisel. A pilot switching control valve is provided in the signal supply path for switching and controlling the valve body of the valve, and a pilot flow passage for guiding the fluid that switches and moves the pilot valve body of the pilot switching control valve is connected to the striking chamber. When the pressure exceeds a predetermined value, the pilot switching valve is switched so that the signal supply path of the control valve holds the control valve in a state where it presses the striking piston away from the chisel. breaker!