JPS6026947Y2 - Hydraulic breaker dry firing prevention device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for preventing dry firing by changing the volume of the accumulator of a hydraulic breaker using an accumulator.

For hydraulic breakers, an accumulator is installed in a part of the machine body,
There are some that make use of that gas pressure.

This type of breaker is very advantageous in that it can operate at a high speed and can handle high output, but it also has disadvantages because it uses gas pressure.

For example, in a hydraulic breaker, if there is no object to be crushed at the tip of the chisel, a total prevention method is provided in which the flow of oil is cut off to prevent the machine from operating.

Therefore, if the chisel comes off the object to be crushed, or if the object to be crushed breaks and disappears from the tip of the chisel, the chisel descends, and this change in position communicates the high pressure side and the low pressure side, preventing dry firing.

However, in the case of a breaker that uses gas with a diaphragm or bladder-type accumulator, if the oil flow has stopped and the full-light prevention device is not working properly, the gas is compressible, so Operation will not stop until the gas has fully expanded within the accumulator.

For this reason, the all-lamp prevention method that controls the flow of oil is ineffective, and there is a risk that a dangerous situation may occur.This not only causes damage to the aircraft, but also requires consideration of worker safety. be.

The present invention aims to solve this problem.

For this reason, a separate accumulator is provided in communication with the breaker's accumulator, and when the switching valve is operated to stop the breaker's operation, the valve provided in the passage connecting both accumulators opens at the same time, reducing the pressure in the accumulator inside the main body. This is what happened.

This will be explained in detail with reference to the drawings.

Reference numeral 1 denotes a hydraulic breaker main body, which has a multi-stage cylinder 2 bored inside, a cylindrical valve 3 with a multi-stage structure on the outside from the top, an operating piston 4 that also has a multi-stage structure on the outside,
A chisel 5 is slidably inserted into the lower part.

Reference numeral 6 denotes an accumulator provided at the top of the main body, the middle part of which is separated by a diaphragm 7, the upper chamber 8 is filled with nitrogen gas, and the lower chamber 9 is connected to a hydraulic pump 12 through oil passages 10 and 11, and is connected to an oil passage 1.
3, 14, and 15 communicate with the cylinder 2, respectively.

The upper chamber 8 of the accumulator 6 communicates by passages 16, 17 with a pressure storage tank 18 formed by a closed tank.

19 is an electromagnetic valve provided in the passage 17, and 20 is a switching valve for operating a breaker provided in the oil passage 11.A limit switch 21 is installed in parallel with the switching valve 20, and the electromagnetic valve is connected through a lead wire 29. The electromagnetic valve 19 is connected to the valve 19, and when the switching valve 20 is operated, the solenoid valve 19 is operated via a limit switch 21 and a lead wire 29.

22 is an oil passage connecting the upper part and the middle part of cylinder 2, 23, 2
4.25 are all oil passages, and the oil passage 27 has a throttle 26.
This leads to tank 28.

The present invention is constructed as described above, and the actual operating situation will be explained below.

When the switching valve 20 is switched to the left side A, the oil from the hydraulic pump 12 enters the lower chamber 9 via the switching valve 20 and oil passages 11 and 10, compresses the upper chamber 8 through the diaphragm 7, and transfers energy to the accumulator 6. to store.

In this case, the electromagnetic valve 19 is switched to the C side without being energized because the switching valve 20 is switched to the A side, and the passage 17 is blocked, so the accumulator 6 acts as an independent accumulator.

At the same time, the valve 3 and the actuating piston 4 are actuated via the oil passages 13, 14, and 15, but since the actuating force that lowers the valve 3 is greater than the actuating force that raises the actuating piston 4, the valve 3 and the actuating piston 4 move rapidly. The lower end of the piston 4 hits the head of the chisel 5 to perform a striking action.

When the working piston 4 reaches the lower limit, the valve 3 and the working piston 4 are separated, and the upper part of the working piston 5 communicates with the tank 28 through the oil passage 25 or through the oil passages 22, 23, etc., so that the working piston 4 is connected to the oil passage. It is pushed up by the oil acting through 15, and further pushes up the valve 3 to reach the upper limit.

In this way, the valve 3 and the operating piston 4 are moved up and down by the pressure oil from the pump 12 to perform work, but when the operation of the operating piston 4 is to be stopped during work, the switching valve 20 is switched to the right side port. However, this activates the limit switch 21, activates the solenoid valve 19 via the lead wire 29, switches to the left side, and opens the accumulator 6 and the pressure storage tank 18 through the passage 17.

If the accumulator 6 were not present, the oil passage 11 would be blocked and the actuating piston 4 would stop at that position.
Since the accumulator 6 is present, the oil in the lower chamber 9 of the accumulator 6 is pushed out to the oil passage 10 and attempts to operate the actuating piston 4 even if the oil passage 10 is blocked and oil is not replenished.

However, in conjunction with the operation of the operating lever 21, the solenoid valve 19 opens, and the compressed gas in the upper chamber 8 escapes to the pressure storage tank 18, and the pressure is dispersed and lowered.

Therefore, the accumulator 6 loses its operating force and does not push oil out of the lower chamber 9, so that the operating piston 4 stops at the position where it existed when the oil passage 11 was blocked and does not move any further.

Therefore, if the tip of the chisel 5 comes off the object to be crushed during work, if the switching valve 20 is operated to cut off the supply of pressure oil from the hydraulic pump 12, the working piston 4 will stop at that moment. The accumulator 6 does not cause any additional operation.

When starting work again, by switching the switching valve 20 to the left side A, not only will pressure oil be supplied to operate the actuating piston 4, but the solenoid valve 19 will also be switched to the right side, blocking the passage 17. Since the accumulator 6 acts as an independent accumulator, the work can be carried out in the state before the work is stopped.

As described above, the present invention is a hydraulic breaker with an accumulator, in which a separate pressure accumulation tank is provided which communicates with the accumulator, and a solenoid valve is provided in the passageway of the hydraulic breaker, so that the solenoid valve is operated in conjunction with the switching valve of the pump circuit. Therefore, if the oil supply is cut off, the solenoid valve will operate and the accumulator and pressure storage tank will communicate, and the operating force of the accumulator on the main body side will disappear.
The operating piston will stop when the oil supply is stopped, and will not operate any further and will operate reliably.
The work is safe and there is no need to worry about damaging the aircraft.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram of an embodiment of the present invention. 1...Main body, 6...Accumulator,
11... Oil passage, 17... Passage, 18.
...Pressure tank, 19...Solenoid valve, 20...
...Switching valve.

Claims (1)

[Scope of utility model registration request] In a hydraulic breaker with a built-in accumulator, a separate accumulator is provided in addition to the accumulator, and both accumulators are connected by a passage and a solenoid valve is installed therein, and the solenoid valve is installed in the oil passage for supplying pressure oil to the main body. Hydraulic breaker full-light prevention device consisting of a similar structure that works in conjunction with a switching valve.