JPH057352Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Field of industrial application] This invention enables earth auger excavation work, which is one of the pile driving operations, to be carried out continuously with the highest efficiency in any soil type, and also allows for remote control. This article relates to a hydraulic circuit for earth auger excavation.

[Prior Art] Pile driving is a part of foundation work when constructing a building, and one of the pile driving operations is to excavate a pilot hole for the pile using an earth auger.

As shown in Fig. 2, this auger excavation device has a power swivel 2 attached to a leader 1 installed upright on the pile driver body.
is slidably provided, and the auger screw 3 is connected to the output shaft 4 of the power swivel 2 so as to move up and down together with the power swivel 2. A sheave 5 is rotatably provided at the upper end of the power swivel 2, and a rope 7 let out from a winch 6 is sequentially wrapped around sheaves 8 and 9 provided at the leader top and the sheave 5 of the power swivel 2. It is fixed to the rear leader top, and the power swivel 2 is pulled up by winding the rope of the winch 6. Also, the rope 11 let out from the other winch 10 is attached to the sheave 1 at the lower end of the leader 1.
2 and is fixed to the power swivel 2, so that a thrust force can be generated on the auger screw by winding the rope around the winch 10.

During the excavation work, the winch 10 is used to wind in the rope and apply thrust force to the auger screw 3.
This is done by rotating the auger screw 3 using the power swivel 2.

Conventionally, the hydraulic motor 1 of this power swivel 2
3. A driving hydraulic circuit for the hydraulic motor 14 of the winches 6 and 10 is shown in FIG.

The hydraulic motor 13 is connected to a hydraulic pump 16 via a pilot type switching valve 15, and the hydraulic motor 14
is the hydraulic pump 1 via the pilot type switching valve 17.
8 is connected.

In the figure, reference numeral 19 indicates a remote control valve, and by operating the remote control valve 19, pilot pressure is applied to the switching valves 15 and 17, and pressure oil from the hydraulic pumps 16 and 18 is directed to the motors 13 and 14 in a desired direction. The switching valves 15 and 17 can be switched so that the water is fed to the water. Further, 20 indicates a hydraulic pump similar to a pilot line, and 21, 22, and 23 each indicate a relief valve.

When performing excavation work using such a hydraulic circuit, the operator operates the remote control valve 19 and switches the switching valve 17 to generate torque in the hydraulic motor 14 and apply thrust force to the auger screw 3. 15 to drive the motor 13 of the power swivel 2.

[Problems to be solved by the invention] However, in the above conventional hydraulic circuit, the remote control valve 1
9 to turn on and off the switching valves 15 and 17. Therefore, when the soil is hard, the thrust force becomes large, and the excavation resistance becomes too large, causing the power swivel motor 13 to stop. The operator turns on and off the switching valve 17 via the remote control valve 19 while observing the rotational state of the auger screw, and performs excavation work while rotating and stopping the motor 14.

For this reason, work efficiency is low, and the skill level of the worker greatly affects work efficiency, and the worker must frequently operate the control valve during work, making remote control or automation impossible. be.

[Means for Solving the Problems] The present invention has been developed in view of the above-mentioned circumstances, and the two hydraulic lines connected to the auger screw winding and lowering motor are connected by an external pilot type relief valve. A pilot line that applies pilot pressure is connected to the vent port of the relief valve, and a sequence valve is provided in the middle of the pilot line, and the sequence valve is used to unload or reduce the normal rotation side hydraulic line pressure of the power swivel hydraulic motor. It is characterized in that it is configured to act as pilot pressure.

[Function] During normal excavation, thrust is applied to the auger screw within the range of relief pressure determined by external pilot pressure, excavation resistance increases, and the hydraulic line pressure on the forward rotation side of the power swivel hydraulic motor exceeds a predetermined value. Then, the sequence valve is activated, reducing the external pilot pressure to a predetermined pressure and relieving the relief valve to reduce the thrust force.

By reducing the thrust force when the excavation resistance increases, the power swivel hydraulic motor does not stop during excavation.

[Example] An example of the present invention will be described below based on the drawings.

Components in FIG. 1 that are the same as those shown in FIG. 3 are given the same reference numerals.

An electromagnetic switching valve 25 is provided in the middle of the pilot line 24 between the remote control valve 19 and the switching valve 17.
A pressure switch 27 is provided on a hydraulic line 26 connecting the switching valve 15 and the hydraulic pump 16, and the pressure switch 27 is connected to a power source 29 via a main switch 28. Moreover, the pressure switch 27 and the electromagnetic switching valve 2
5 is electrically connected to the pressure switch 2.
The solenoid switching valve 25 is energized to the M position by the a contact of 7 and to the L position by the b contact.
Note that it is normally a b contact.

2 hydraulic lines connecting the hydraulic motor 14 and the switching valve 17, a press-fit line 30, and a hoisting line 3;
1 is connected by an external pilot type relief valve 32, and external pilot pressure is applied in the direction of closing the relief valve 32. A pilot line 33 connected to the relief valve 32 is connected to a tank 35 via a sequence valve 34 and to the tank 35 via a pilot pressure setting valve 36. Incidentally, the pilot line 33 is provided with a press force indicator 37.

Among the hydraulic lines connecting the hydraulic motor 13 and the switching valve 15, that is, the normal rotation line 38 and the reverse rotation line 39, the normal rotation line 38 and the sequence valve 34 are connected by a pilot line 40, and a throttle valve is connected to the pilot line 40. 41 is provided to adjust the switching operation of the sequence valve 34.

The operating pressure of the relief valve 21 is P ₁ , the operating pressure of the pressure switch 27 is P ₂ which is slightly lower than P ₁ , the operating pressure of the sequence valve 34 is P ₃ which is even slightly lower than P ₂ ,
The setting pressure of the pilot pressure setting valve 36 is P ₄ , and P ₁
>P ₂ >P ₃ >P ₄ >0.

Next, the operation will be explained.

When the hydraulic circuit is not in operation, the hydraulic circuit is in the state shown in the figure, and in order to put the circuit into the operating state, the main switch 28 is turned on. Pressure switch 27 to electromagnetic switching valve 25
The electromagnetic switching valve 25 is energized through the b contact of the m
position and communicate with the pilot line 24.

In order to operate this circuit, the pressure of the pilot line 33 is set in advance by the pilot pressure setting valve 36 according to the soil quality, and the remote control valve 19 is operated to switch the switching valve 15 between the hydraulic line 26 and the hydraulic line 26. The hydraulic motor 13 is rotated in the normal rotation direction by communicating with the normal rotation line 38. Similarly, the switching valve 17 is switched by operating the remote control valve 19 to connect the press-fit line 30 and the hydraulic pump 18 to drive the winch 10 and apply thrust force to the auger screw 3.

Note that this thrust force is determined by the relief pressure of the relief valve 32, that is, the external pilot pressure, and the pilot pressure is set by the pilot pressure setting valve 36. That is, although there is an optimal thrust force depending on the soil quality, the pilot pressure setting valve 36 allows the thrust force to be selected to an appropriate value.

Next, the excavation resistance of the auger screw increases due to changes in the soil quality, and when the pressure in the normal rotation line 38 reaches around the allowable pressure _P3 , the sequence valve 34 is activated and the pilot line 33 of the relief valve 32 is transferred to the tank. Connects to 35. Therefore, the external pilot pressure is reduced, the press-fit line 30 and the hoist line 31 are brought into communication, and while they are in communication, the press-in force of the auger screw 3 is reduced or eliminated. Augus Screw 3
The hydraulic motor 13 rotates without stopping due to the reduction in the pressing force and thrust force. As the auger screw 3 is driven by the hydraulic motor 13, the oil pressure in the normal rotation line 38 decreases. As the oil pressure decreases, the sequence valve 34 closes the pilot line 33 again, so the pilot pressure in the pilot line 33 returns to the set pressure, and the set thrust force acts on the auger screw.

However, if the soil change has not been resolved by the time the sequence valve 34 returns, the pressure in the normal rotation line 38 will increase again, the unload valve 34 will operate, and the above-described operation will be repeated. Become. In this case, since the throttle valve 41 is provided in the pilot line 40, there is a delay in the operation of the unload valve 34, and a thrust force is generated corresponding to this delay. Therefore, the normal rotation line 38 is under pressure.
Even if P ₃ is reached, the thrust force will not immediately decrease and the engine will idle, but instead the excavation will be carried out gradually.

Furthermore, if the discharge pressure of the hydraulic pump 16 exceeds P ₃ and reaches P ₂ due to a stone or the like being caught, the pressure switch 2
7 operates, and the electromagnetic switching valve 25 is energized via the a contact. The electromagnetic switching valve 25 switches to the switching valve 1.
7 is switched, and pressure oil is supplied to the hydraulic motor 14 in the hoisting direction. That is, the auger screw 3 is pulled up only when the pressure switch 27 is activated.

When the pressure in the hydraulic line 26 drops below _P2 , the pressure switch 27 returns and becomes the B contact.
The electromagnetic switching valve 25 and the switching valve 17 are respectively switched, and thrust force is applied to the auger screw again.

The operations described above are performed as appropriate depending on the excavation state while the remote control valve 19 is operated in one direction, and there is no need for the operator to operate the lever each time.

Incidentally, remote control valves may be provided individually for each of the switching valves 15 and 17, and the pilot pressure setting valve 36 may be a pressure reducing valve other than the variable pressure relief valve shown in the figure, or a set of relief valves 32 may be provided. may be fixed. Furthermore, a pressure switch 27,
Of course, the overload prevention mechanism such as the electromagnetic switching valve 25 may be omitted, and the portion corresponding to the mechanism may be manually operated by the operator. Furthermore, it goes without saying that the switching valves 15 and 17 can be operated directly without using a remote control valve.

[Effects of the invention] As described above, according to the invention, the operator can set the thrust force according to the soil quality and simply turn on the switching valve for the hydraulic motor of the power swivel and the switching valve for the auger screw winding vertical hydraulic motor.・Since all you need to do is turn it off, the excavation work is greatly simplified and highly efficient excavation work is possible without requiring any skill.

[Brief explanation of the drawing]

Figure 1 is a hydraulic circuit diagram for excavation according to the present invention, Figure 2
The figure is an explanatory diagram showing an outline of the auger screw drive relationship, and FIG. 3 is a conventional excavation hydraulic circuit diagram. 2 is power swivel, 3 is auger screw,
13 and 14 are hydraulic motors, 30 is a press-fit line, 3
1 is a hoisting line, 32 is a relief valve, 33 is a pilot line, 34 is a sequence valve, 38 is a normal rotation line, and 40 is a pilot line.

Claims (1)

[Scope of utility model registration request] The two hydraulic lines connected to the auger screw winding and lowering motor are connected with an external pilot type relief valve, and a pilot line that applies pilot pressure is connected to the vent port of the relief valve, and a sequence valve is installed in the middle of the pilot line. 1. A hydraulic circuit for earth auger excavation, characterized in that the sequence valve is configured so that normal rotation side hydraulic line pressure of a power swivel hydraulic motor acts as pilot pressure for unloading or pressure reduction.