JPS6250400B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operating circuit for a hydraulic winch used in a hydraulic crane or a hydraulic pile driver.

The operating circuit of a conventional hydraulic winch capable of freefall will be explained with reference to FIG. In FIG. 1, 1 is a hydraulic power source for a hydraulic motor 3 for two rotations of the hoisting drum, 4 is a directional switching valve provided in a conduit on the discharge side of the hydraulic power source 1, and 5 is a hydraulic power source in a conduit on the discharge side of the hydraulic power source 1. The connected main relief valves 6A are the first main pipes through which oil flows from the directional control valve 4 to the hydraulic motor 3 during hoisting, and 6B are the first main pipes through which oil flows from the directional control valve 4 to the hydraulic motor 3 during hoisting. This is the second main conduit. Reference numeral 7 designates a counterbalance valve, which includes a main valve 8 which is provided in the second main pipe line 6B and uses the oil pressure of the first main pipe line 6A as a pilot pressure, and a check valve which is provided in a bypass pipe line of the main valve 8. It consists of 9. 10 is a manual two-position switching valve provided between the first and second main pipes 6A and 6B, and is a switching valve that selects whether the pipes of the oil inlets and outlets J and I of the hydraulic motor 3 are connected or made independent. It is. 11 is a drum brake attached to the hoisting drum 2, 12 is a brake cylinder, 13 is a wire rope wound around the hoisting drum 2, and 14 is a suspended load lifted by the wire rope 13.

This circuit includes the following circuit that operates the brake cylinder 12 at the same time as switching the directional switching valve 4 by hydraulic operation. 15 is a hydraulic power source provided separately from the hydraulic power source 1; 16 is a relief valve connected to the discharge side pipe; 17 is a shuttle valve 18 for supplying and discharging oil between the directional control valve 4 and the brake cylinder 12; The pilot valve 17 is a manual pilot valve that switches between the discharge pipe 19 of the hydraulic power source 1 and the return pipe 2 to the tank 20.
1 is connected in common to two valves 22, 2, respectively.
3 and an operating lever 24, and the oil inlet/outlet A of one valve 22 is connected to a pilot chamber of one of the directional control valve 4 and the shuttle valve 18, respectively.
The oil inlet/outlet B of the other valve 23 is commonly connected to the pilot pipes 27, 28 which are connected to the pilot chambers of the other valve 4, 18. The shuttle valve 18 is a three-position switching valve, and when it is in the center position, the hydraulic power source 1
The discharge pipe 29 of the brake cylinder 12 is temporarily cut off, and the oil in the brake cylinder 12 is discharged to the tank 31 via the pipe 30. is supplied to the brake cylinder 12 to release the brake.

In this operating circuit, when the operating lever 24 of the pilot valve 17 is operated to the b side, pressure oil from the hydraulic source 15 is supplied to the D port of the directional control valve 4 through the valve 23 and the pilot pipe 27, and Switch valve 4 in the Y direction. At this time, the oil discharged from the C port flows through the pilot pipe 25 and the valve 2.
2 to the tank 20. At the same time, pressure oil is supplied to the left pilot chamber of the shuttle valve 18 through the pilot pipe 28, so the pipe 29
Pressure oil is supplied to the brake cylinder 12 through the conduit 30, and the brake of the hoisting drum 2 is released. By switching the directional control valve 4 in the Y direction, the pressure oil from the hydraulic source 1 is transferred to the directional control valve 4, the E port of the counterbalance valve 7, the check valve 9, the G port of the counterbalance valve 7, the second Main pipeline 6B,
After entering the motor 3 from the I port of the motor 3 and flowing out from the J port, the motor 3 is driven in the winding direction of the drum 2, and then the first main pipe 6
A. Returns to tank 32 via directional control valve 4.

On the other hand, move the operating lever 24 of the pilot valve 17 to a
When operated to the side, the flow of pilot pressure oil in the opposite direction to the above causes the directional control valve 4 to switch in the X direction, and the pressure oil from the hydraulic source 1 is transferred from the directional control valve 4 to the F port of the counterbalance valve 7, It passes through the H port and enters the motor 3 from the J port. Then, by the action of the main valve 8 of the counterbalance valve 7, the motor 3 is driven in the lowering direction of the drum 2 while maintaining back pressure at the G port of the counterbalance valve 7.
The oil that comes out is sent to the G port of the counterbalance valve 7,
Tank 3 via main valve 8, E port, directional valve 4
Return to 2. That is, power lowering is performed.

Next, when performing a free haul of the hydraulic winch, the two-position switching valve 10 is manually switched, and then the operating lever 24 of the pilot valve 17 is operated to the a side to prevent cavitation. In this case, the motor 3 is short-circuited via the switching valve 10, that is, the oil coming out of the I port of the motor 3 passes through the switching valve 10 and returns to the J port of the motor 3, forming a closed circuit. do. Since there is nothing in this closed circuit that causes a large pressure loss other than pipe resistance, the pressure difference between the outlet and inlet (J, I ports) of the motor 3 is also very small, and the suspended load holding power of the motor 3 is almost negligible. It's gone, hanging load 1
The hoisting drum 2 rotates while being pulled by the motor 3, and the oil is circulated in the closed circuit by the pumping action of the motor 3. In other words, a free fall is possible.

In this operating circuit, when performing a freefall, the two-position switching valve 10 and the lever 24 of the pilot valve 17 must be operated, which is cumbersome to operate. Furthermore, if a normal lowering operation is performed with the two-position switching valve 10 switched to the free fall state, both the hydraulic brake and the drum brake will be released, causing the suspended load to fall.

The purpose of the present invention is to eliminate the need to operate two levers during freefall work, and to enable freefall and power lowering without checking the switching state of the 2-position switching valve for freefall. An object of the present invention is to provide a hydraulic winch operating circuit configured to improve safety.

In order to achieve this objective, in the present invention,
Two pilot valves each having an operating lever are provided as pilot valves of the directional switching valve for switching the rotational direction of the hydraulic motor for the hoisting drum, and the pilot pipes of each pilot valve are connected through valves that prevent oil communication between them. The pilot pipes are commonly connected to the pilot chambers of the directional switching valves, and the pilot pipe line to which pressure oil is supplied when lowering one pilot valve is connected to the pilot chamber of the two-position switching valve for shorting the pipe line of the motor. It is characterized by

The details of the present invention will be explained below with reference to an embodiment shown in FIG. In FIG. 2, the same reference numerals as in FIG. 1 indicate the same or corresponding parts. Reference numeral 17 is a pilot valve having an operating lever 24 as described above, but pressure oil is supplied from the hydraulic source 15 during lowering. A pipe line 36 is connected to the pilot pipe line 25 which is connected to a pilot chamber of a hydraulically operated two-position switching valve 35. 33 is pilot valve 1
This is a pilot valve having the same configuration as No. 7, consisting of an operating lever 37 and two valves 38 and 39,
When the operating lever 37 is operated to the side a, one pilot line 42 is communicated with the discharge line 40 of the hydraulic power source 15 via the valve 38, and the other pilot line 4
3 communicates with a return pipe 41 via a valve 39. Further, when the operating lever 37 is operated to the b side, one pilot pipe 42 is connected to the return pipe 41 via the valve 38, and the other pilot pipe 42 is connected to the return pipe 41 via the valve 38.
3 communicate with a discharge pipe 40 via a valve 39, respectively. Each pilot line 42, 43 is commonly connected to the pilot line 46, 47 of the directional control valve 3 through a shuttle valve 44, 45 together with the pilot line 25, 27, respectively. Shuttle valves 18 for supplying and discharging oil from the brake cylinder 12 at 46 and 47, respectively.
Pilot lines 26 and 28 are connected to.

In this operation circuit, when the operation lever 24 of the pilot valve 17 is operated to the a side (lowering side),
Pressure oil from the hydraulic source 15 is supplied to the C port of the directional control valve 4 via the valve 22, the pilot line 25, the shuttle valve 44, and the pilot line 46, while the discharged oil from the D port is supplied to the pilot line 46. Road 4
7. Returns to tank 20 via shuttle valve 45, pilot line 27, valve 23, and return line 21.
Therefore, the directional switching valve 4 is switched in the X direction, but at the same time, pressure oil is also supplied to the 2-position switching valve 35 via the pilot line 36, so the switching valve 35 is switched and the pipes are shorted. Also, since the shuttle valve 18 is switched,
The braking state by the brake cylinder 12 is released and a free fall state is entered. Conversely,
When the operating lever 24 is operated to the b side (hoisting side), the directional switching valve 4 is switched to the Y direction, but at this time, the normal hoisting operation is performed because pilot pressure oil is not supplied to the 2-position switching valve 35. be exposed. Note that this normal hoisting operation can be performed by a pilot valve 33, which will be described later, so the pilot valve 17 may be configured to switch only in the a direction (lowering direction).

On the other hand, move the operating lever 37 of the pilot valve 33 to a
side (lowering side) and b side (winding side), the direction switching valve 4 is switched to the X direction and the Y direction, respectively, and at the same time, the shuttle valve 18 is switched to release the brake, and the shuttle valve 44
Due to this action, pilot pressure oil is not supplied to the two-position switching valve 35 via the pilot pipe line 36, so that normal hoisting and lowering operations are performed.

When the operating levers 24 and 37 are both in the neutral state, the directional control valve 4 is in the intermediate position, and the I port of the motor 3 is connected to G, E, M, L, F, H.
Since the closed circuit leading to the J port via each port is cut off, the hydraulic brake is applied.

As described above, in the present invention, two pilot valves each having an operating lever are provided as the pilot valves of the directional switching valve for switching the rotational direction of the hydraulic motor for the hoisting drum, and the pilot pipes of the customer pilot valves are mutually connected. The pilot pipes are commonly connected to the pilot chambers of the directional control valves through a valve that prevents oil communication between them, and the pilot pipes to which pressure oil is supplied when one pilot valve is lowered are used to short-circuit the motor pipes. Since it is connected to the pilot chamber of the hydraulically operated two-position switching valve, in the case of free fall, operating one pilot valve to the lowering side will short-circuit the motor pipe and switch the directional switching valve.
There is no need to operate two operation levers, and there is no need to check the switching state of the two-position switching valve for shorting the pipe of the motor, allowing for selective free fall and power lowering. Therefore, the erroneous operation of releasing both the hydraulic brake and the drum brake and causing the suspended load to fall when power should be lowered is prevented, and safety is improved.

Although the above description has focused on a hydraulic crane, the present invention is also applicable to a hydraulic pile driver winch, and a throttle valve is provided in series with a two-position switching valve for shorting the motor to limit the descending speed. You can also do that.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing an operating circuit of a conventional hydraulic winch, and FIG. 2 is a hydraulic circuit diagram showing an embodiment of the operating circuit of a hydraulic winch according to the present invention. 2... Hoisting drum, 3... Hydraulic motor, 4...
Directional switching valve, 7...Counter balance valve, 11...
...Drum brake, 12...Brake cylinder,
17, 33... Pilot valve, 18... Shuttle valve, 25-28, 42, 43... Pilot pipe line, 24, 37... Operation lever, 35... 2-position switching valve.

Claims (1)

[Claims] 1. A hydraulic motor for rotating the hoisting drum, a directional switching valve that switches the flow direction of oil from a hydraulic source to the hydraulic motor, and a counterbalance valve provided in a conduit between the hydraulic motor and the directional switching valve; The operating circuit for a hydraulic winch includes a two-position switching valve that short-circuits an inlet and an outlet of a hydraulic motor, and includes two pilot valves each having an operating lever as a pilot valve of the directional switching valve, and a pilot pipe line for each pilot valve. are commonly connected to the pilot chambers of the directional control valves through a valve that prevents oil communication between them, and a pilot pipe line to which pressure oil is supplied when one pilot valve is lowered is connected to the pilot pipe of the hydraulic motor. An operating circuit for a hydraulic winch, characterized in that it is connected to a pilot chamber of a hydraulically operated two-position switching valve for short circuit.