JP2023082566A - Hydraulic control device - Google Patents

Abstract

To provide a hydraulic control device which can smoothly open a door body with minimum resistance when the door body is opened and can suppress flapping of the door body due to waves when the door body is closed by its own weight, and a hydraulic control device which can start and end a forced opening operation of a gate only by operating a hydraulic pump without operating a valve or the like.SOLUTION: A hydraulic control device of a gate comprises: a double-rod type hydraulic cylinder 3 having a rod 8 that moves in conjunction with movement of hydraulic oil, a front oil port 3a, and a rear oil port 3b; a door body 1 opening/closing in conjunction with the rod 8; a first communication pipe 10 having a check valve 11; a second communication pipe 12 having a float valve 4b and a flow control valve 13; a hydraulic pump 17 supplying hydraulic oil; a hydraulic oil supply pipe 14 connecting the hydraulic pump 17 to a front side of the check valve 11 and having a check valve 15a for supplying; and a hydraulic oil discharge pipe 16 connecting a hydraulic tank 18 to a rear side of the check valve 11 and having a check valve 15b with a discharge pilot.SELECTED DRAWING: Figure 6

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for appropriately controlling the opening and closing of a flap gate or the like installed at a sluice gate or outlet of a running water channel for the purpose of preventing backflow.

Conventionally, a flap gate or the like is installed at the exit of a general sluice gate or running water channel for the purpose of preventing backflow from the downstream side.
However, since conventional flap gates are installed with the door suspended from hanging hardware, the drainage performance is low because the water passage is normally closed. In addition, when the water level on the downstream side fluctuates violently due to waves, etc., the door body repeats opening and closing violently in sync with the water level fluctuation, and the violent collision between the door body and the door stop hardware repeats for a long time. , there were problems such as noise and damage.

Therefore, the present applicant normally holds the door in an open state, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2019-112860, particularly paragraphs 0020 to 0021 and FIGS. 4 and 5). In addition, when the water level on the downstream side reaches a predetermined level or higher, the float valve switches to the closed position, so that the door body is closed by its own weight and water can be reliably stopped. We have developed a hydraulic control system for forced open gates.

JP 2019-112860 A

However, in the hydraulic control device for a forced-open gate described in Patent Document 1, when the door automatically opens and closes (states shown in Figs. Set by (11), the opening and closing speed of the door is always below the predetermined speed. Therefore, when the door is opened only by the water pressure of the drainage flow from the upstream side (state in Fig. 6), it opens quickly. I had a problem with it not working.
Furthermore, when forcibly opening the flap gate, it is necessary to close the first stop valve (12) and open the second stop valve (13) to change the state shown in FIG. 6 to the state shown in FIG. After the forced opening operation is completed, it is necessary to perform the opposite operation.
The present invention solves these problems, and when the gate body is opened by the water pressure of the drainage flow from the upstream side, it can be smoothly opened with minimum resistance, and the downstream side is above a predetermined water level. When the float valve switches to the closed door position and the door body closes due to its own weight, the closing operation is made at a gentle operating speed to suppress flapping of the door body due to waves. A first object is to provide a control device.
In addition, the gate can be forcibly opened simply by activating the hydraulic pump without manipulating the valves. The second task is to provide

The invention according to claim 1 is
A hydraulic control device for a gate that is closed by its own weight,
A double-rod hydraulic cylinder (3) having a rod (8), a front oil port (3a) and a rear oil port (3b) that move in conjunction with the movement of hydraulic oil,
When the rod (8) moves to the side where the front oil port (3a) exists, it moves in the closing direction, and when the rod (8) moves to the side where the rear oil port (3b) exists, it moves in the opening direction. 1) and
a first communicating pipe (10) communicating between the front oil port (3a) and the rear oil port (3b);
a check valve (11) provided in the first communication pipe (10) that allows hydraulic oil to flow only in the direction from the rear oil port (3b) to the front oil port (3a);
a second communicating pipe (12) communicating between the front side and the rear side of the check valve (11) in the first communicating pipe (10);
A float valve (4b) which is provided in the second communication pipe (12) and which opens when the water level (19b) on the downstream side of the gate reaches or exceeds a predetermined water level, and the flow rate of hydraulic oil does not exceed a predetermined flow rate. It is characterized by having a flow control valve (13) for adjusting the flow rate.

The invention according to claim 2 is the hydraulic control device according to claim 1,
A hydraulic tank (18) that stores hydraulic oil;
a hydraulic pump (17) that supplies hydraulic oil from the hydraulic tank (18) to the double-rod hydraulic cylinder (3);
The hydraulic fluid outlet of the hydraulic pump (17) and the first communication pipe (10) are closer to the front fluid port (3a) than the check valve (11) or the hydraulic fluid outlet and the second communication pipe (12). a hydraulic oil supply pipe (14) connecting the front oil port (3a) side from the float valve (4b) and the flow control valve (13);
a supply check valve (15a) provided in the hydraulic oil supply pipe (14);
The rear oil port (3b) side of the check valve (11) between the hydraulic tank (18) and the first communicating pipe (10) or the hydraulic tank (18) and the second communicating pipe (12) a hydraulic oil discharge pipe (16) connecting the rear oil port (3b) side of the float valve (4b) and the flow control valve (13);
a check valve with a discharge pilot (15b) provided in the hydraulic oil discharge pipe (16),
The hydraulic pump (17), the hydraulic oil supply pipe (14), the supply check valve (15a), the first communication pipe (10) and the front oil port (3a) are connected from the hydraulic tank (18). When hydraulic oil is supplied to the double-rod hydraulic cylinder (3) through the double-rod hydraulic cylinder (3), the rear oil port (3b), the first communication pipe (10), the hydraulic oil Hydraulic oil is discharged to the hydraulic tank (18) through the discharge pipe (16) and the discharge pilot check valve (15b).

The invention according to claim 3 is the hydraulic control device according to claim 2,
The hydraulic tank (18), the hydraulic pump (17), the hydraulic oil supply pipe (14), the supply check valve (15a), the hydraulic oil discharge pipe (16), and the check valve with pilot for discharge. (15b) is detachably connectable to the first communication pipe (10) or the second communication pipe (12).

According to the first aspect of the invention, the first communicating pipe (10) communicating the front oil port (3a) and the rear oil port (3b) of the double-rod hydraulic cylinder (3); ) is provided in a check valve (11) that allows hydraulic oil to flow only in the direction from the rear oil port (3b) to the front oil port (3a), the front side and the rear side of the check valve (11) A communicating second communicating pipe (12), a float valve (4b) that is provided in the second communicating pipe (12) and opens when the water level (19b) on the downstream side of the gate reaches a predetermined water level or higher, and a flow of hydraulic oil. Since the flow control valve (13) is provided to adjust the flow rate so that it does not exceed a predetermined flow rate, when the float valve (4b) is closed, there is resistance in the direction from the rear oil port (3b) to the front oil port (3a). Hydraulic oil flows freely, and the door body (1) is smoothly opened by the water pressure of the drainage flow from the upstream side. Since hydraulic oil does not flow from the front oil port 3a to the rear oil port 3b, once the door body 1 is opened, the open state can be maintained.
Further, when the float valve (4b) is open, hydraulic oil flows from the front oil port (3a) to the rear oil port (3b) through the flow control valve (13), so the door body (1) is kept under its own weight. , the flow rate control valve (13) operates at a slow operating speed, and flapping of the door (1) due to waves can be suppressed.

According to the invention of claim 2, in addition to the effects of the invention of claim 1, the hydraulic oil supply pipe (14) and the check valve for supply are provided for forcibly opening the door (1). Equipped with a valve (15a), a hydraulic oil discharge pipe (16), a check valve with a discharge pilot (15b), a hydraulic pump (17) and a hydraulic tank (18). When hydraulic oil is supplied to the double rod hydraulic cylinder (3) through the hydraulic oil supply pipe (14), supply check valve (15a), first communication pipe (10) and front oil port (3a), , the hydraulic tank (18 ), the gate can be forcibly opened simply by operating the hydraulic pump (17). It is possible to provide a hydraulic control device without

According to the invention of claim 3, in addition to the effects of the invention of claim 2, the hydraulic tank (18), which is a forced opening device for forcibly opening the door (1), and the hydraulic pump (17), a hydraulic oil supply pipe (14), a supply check valve (15a), a hydraulic oil discharge pipe (16) and a check valve with a discharge pilot (15b) are connected to the first communication pipe (10) or the first Since it can be detachably connected to the two communication pipes (12), there is no need to permanently install the forced opening device, and the destruction of the forced opening device by an earthquake, tsunami, strong wind, mischief, etc. can be prevented.

1 is a perspective view of an upper hinge type flap gate according to Embodiment 1. FIG. FIG. 4 is a diagram showing the state of the hydraulic operating device, etc., according to the first embodiment (at the time of automatic opening operation); FIG. 4 is a diagram for explaining the flow of hydraulic oil in Embodiment 1 (at the time of automatic opening operation); FIG. 4 is a diagram for explaining the flow of hydraulic oil in Embodiment 1 (at the time of automatic closing operation); FIG. 4 is a diagram showing the states of the hydraulic operating device and the like according to the first embodiment (when closed); FIG. 10 is a view showing the state of the hydraulic operating device, etc., according to the second embodiment (at the time of automatic opening operation); The figure explaining the flow of the hydraulic oil in Example 2 (at the time of forced opening). FIG. 11 is a diagram showing the states of the hydraulic operating device, etc., according to the third embodiment (at the time of forced opening); The figure which shows the modification of the hydraulic operating device etc. which concern on Example 2 (at the time of an automatic opening operation).

The embodiments of the present invention will now be described with reference to examples.

FIG. 1 is a perspective view of an upper hinge type flap gate according to Embodiment 1. FIG.
In the upper hinge type flap gate according to the first embodiment, as shown in FIG. When it is not working, its own weight closes the outlet of the upstream channel.
A door drive arm 1a is provided on the upper part of the door 1, and is hinged to a metal tip 9 provided at the tip of the rod 8 of the double-rod hydraulic cylinder 3, so that the door 1 can be opened and closed. and the rod extension/retraction operation of the double-rod hydraulic cylinder 3 are always synchronized.
The double-rod hydraulic cylinder 3 is oscillatably attached to a trunnion bearing 7. When the door 1 is opened, the rod 8 is retracted, and when the door 1 is closed, the rod 8 is extended. Conversely, when the rod 8 retracts, the door 1 opens, and when the rod 8 extends, the door 1 closes.
Further, a float 4a and a float valve 4b, which will be described later, are housed inside the float device storage box 4c, and door stops 5 are provided around the outlet of the upstream water channel.

FIG. 2 is a diagram showing the state of the hydraulic operating device and the like according to the first embodiment during an automatic opening operation, and FIG. 3 is a diagram explaining the flow of hydraulic oil in that state.
The front oil port 3a and the rear oil port 3b of the double-rod hydraulic cylinder 3 are communicated by a first communication pipe 10, and the first communication pipe 10 operates only in the direction from the rear oil port 3b to the front oil port 3a. A check valve 11 is provided to allow oil to flow.
The front side (closer to the front oil port 3a) and the rear side (closer to the rear oil port 3b) of the check valve 11 in the first communicating pipe 10 are communicated by a second communicating pipe 12. The two communication pipes 12 are provided with a float valve 4b that opens when the downstream water level 19b in the water channel 2b on the downstream side of the gate reaches a predetermined water level or higher, and a flow rate that adjusts the flow rate of hydraulic oil so that it does not exceed a predetermined flow rate. A control valve 13 is provided.
Here, the double-rod hydraulic cylinder 3 is in a state where the hydraulic oil flows freely between the front oil port 3a and the rear oil port 3b due to the characteristic that the amount of hydraulic oil inside the cylinder does not change even if the rod 8 expands and contracts. By doing so, it has a characteristic that the rod 8 can be freely expanded and contracted by an external force.
Therefore, in the state shown in FIG. 2 in which the downstream water level 19b is lower than the predetermined water level, the float 4a is lowered, and the float valve 4b is closed, the second communication pipe 12 is closed, and the hydraulic oil Since it is possible to flow only in the direction from the oil port 3b to the front oil port 3a, the gate is opened and held so that only the rod 8 of the double-rod hydraulic cylinder 3 can be retracted.
In the gate open holding state, as shown in FIG. 3, the door 1 tries to open in the water discharge direction due to the water pressure of the upstream water level 19a, and the rod 8 tries to move in the direction of the black arrow.
As a result, hydraulic oil flows in the first communication pipe 10 from the rear oil port 3b to the front oil port 3a as indicated by the white arrows, thereby performing an automatic opening operation.
Then, even if the upstream side water level 19a drops thereafter and the water pressure becomes small, the hydraulic oil cannot flow in the first communicating pipe 10 in the direction from the front oil port 3a to the rear oil port 3b. The rod 8 of the hydraulic cylinder 3 cannot be extended, and the open state of the door 1 is maintained.

FIG. 4 is a diagram for explaining the flow of hydraulic oil in the first embodiment during an automatic closing operation, and FIG. 5 is a diagram showing the state of the hydraulic operation device and the like according to the first embodiment when the door body 1 is closed. .
When the downstream side water level 19b rises from the state shown in FIG. 3, the float 4a rises, and the float valve 4b opens, the state shown in FIG. The rod 8 can be extended and retracted.
In this state, the door 1 can perform automatic opening and closing operations corresponding to fluctuations in the upstream water level 19a and the downstream water level 19b.
That is, when the upstream water level 19a is higher than the downstream water level 19b and the water pressure in the drainage direction of the upstream water level 19a is greater than the water pressure due to the downstream water level 19b and the pressure due to the weight of the gate body 1, the automatic An opening operation is performed and water is drained from the upstream side of the gate to the downstream direction.
Conversely, when the upstream water level 19a is lower than or about the same as the downstream water level 19b, and the water pressure in the drainage direction of the upstream water level 19a is smaller than the water pressure due to the downstream water level 19b and the pressure due to the weight of the gate body 1. As shown in FIG. 4, the gate 1 tries to close in the gate direction due to the water pressure due to the downstream water level 19b and the weight of the gate 1, and the rod 8 tries to move in the direction of the black arrow.
Then, the hydraulic oil flows in the first communicating pipe 10 and the second communicating pipe 12 from the front oil port 3a to the rear oil port 3b as indicated by the white arrows, so that the door body 1 moves in the closing direction. An automatic closing operation is performed, and finally the state shown in FIG. 5 is reached.
At this time, the flow rate of the hydraulic oil flowing through the second communicating pipe 12 does not exceed a predetermined flow rate due to the action of the flow control valve 13, so that the extension operation speed of the rod 8 is limited, and the automatic closing operation of the door 1 is performed. The speed becomes slow. Therefore, it is possible to prevent the door 1 from closing at high speed and causing a violent collision with the door stop hardware 5, thereby preventing the occurrence of noise and damage.

FIG. 6 is a diagram showing the state of the hydraulic operating device and the like according to the second embodiment during the automatic opening operation.
The upper hinge type flap gate according to the second embodiment and the upper hinge type flap gate according to the first embodiment have exactly the same structure. The float 4a, the float valve 4b and the flow control valve 13 have exactly the same construction.
Embodiment 2 differs from Embodiment 1 in that hydraulic oil supply pipe 14, supply check valve 15a, hydraulic oil discharge pipe 16, discharge pilot check valve 15b, hydraulic pump 17 and hydraulic tank 18 is provided. Therefore, the same numbers are given to the members and the like that are common to the first embodiment, and the points different from the first embodiment will be mainly described below.

As shown in FIG. 6, the hydraulic operating device of the second embodiment has a hydraulic tank 18 that stores hydraulic oil and a hydraulic pressure that supplies the hydraulic oil from the hydraulic tank 18 to the double-rod hydraulic cylinder 3 in addition to the hydraulic operating device of the first embodiment. A pump 17, a hydraulic fluid supply pipe 14 that connects the hydraulic fluid outlet of the hydraulic pump 17 and the front oil port 3a side of the check valve 11 of the first communication pipe 10, and a supply check provided on the hydraulic fluid supply pipe 14 A valve 15a, a hydraulic oil discharge pipe 16 connecting the hydraulic tank 18 and the oil port 3b side behind the check valve 11 of the first communication pipe 10, and a check valve 15b with a discharge pilot provided in the hydraulic oil discharge pipe 16. is added.
Unless the hydraulic pump 17 is operated, hydraulic fluid will not flow through the hydraulic oil supply pipe 14 and the hydraulic oil discharge pipe 16 due to the check valve 15a for supply and the check valve 15b with pilot for discharge. , in the state where the float valve 4b is closed, as in FIG. flows in the direction from the rear oil port 3b to the front oil port 3a to perform an automatic opening operation. Since the oil does not flow in the direction of the rear oil port 3b, the rod 8 of the double-rod hydraulic cylinder 3 cannot be extended and the door 1 is kept open.
When the float valve 4b is open, the rod 8 of the double-rod hydraulic cylinder 3 can be extended and retracted in the same manner as in the first embodiment, and the door 1 is at the upstream water level 19a and the downstream water level 19b. An automatic opening/closing operation is performed corresponding to the fluctuation of

FIG. 7 is a diagram for explaining the flow of hydraulic oil in the second embodiment during forced opening.
During forced opening, the hydraulic pump 17 is operated to supply hydraulic oil from the hydraulic tank 18. - 特許庁
Hydraulic oil supplied from the hydraulic tank 18 flows through the hydraulic oil outlet of the hydraulic pump 17, the hydraulic oil supply pipe 14, the supply check valve 15a, the hydraulic oil supply pipe 14, the first communication pipe 10 and the The oil is supplied to the front oil chamber via the front oil port 3a.
Since the rod 8 is contracted when hydraulic fluid is supplied to the front oil chamber, the hydraulic fluid in the rear oil chamber flows through the rear oil port 3b, the first communication pipe 10, the hydraulic oil discharge pipe 16, It is discharged to the hydraulic tank 18 via the check valve 15b with a discharge pilot and the hydraulic oil discharge pipe 16.
As a result, the tip fitting 9 moves toward the double-rod hydraulic cylinder 3, so that the door 1 is forcibly opened.
The discharge pilot check valve 15b operates to block the flow of hydraulic oil from the rear oil port 3b to the hydraulic tank 18 except when hydraulic oil is supplied from the hydraulic tank 18 by the hydraulic pump 17. .

FIG. 8 is a diagram showing the state of the hydraulic operating device and the like according to the third embodiment at the time of forced opening.
The upper hinged flap gate according to the third embodiment has exactly the same structure as that of the upper hinged flap gate according to the first embodiment, and the hydraulic operating device for forced opening consists of the hydraulic oil supply pipe 14 and the operating valve. The configuration is the same as that of Example 2 except that the oil discharge pipe 16 is connected to the supply connection port 14a and the discharge connection port 16a, respectively.
Therefore, the same numbers are given to the members and the like that are common to the first and second embodiments, and the differences from the second embodiment will be mainly described below.

During normal operation (during automatic opening, automatic closing, and closing), the hydraulic operation device of the third embodiment includes a hydraulic oil supply pipe 14, a supply check valve 15a, a hydraulic oil discharge pipe 16, and a discharge pilot. The forced opening device consisting of the check valve 15b, the hydraulic pump 17 and the hydraulic tank 18 is not connected, and due to factors such as low water pressure at the upstream water level, the opening angle is small and the drainage capacity is low. If the check valve 11 of the first communicating pipe 10 is on the front oil port 3a side of the check valve 11, the supply connection port 14a and the rear oil port 3b side of the check valve 11 of the first communicating pipe 10 are connected. The hydraulic pump 17 is operated after connecting the hydraulic oil supply pipe 14 and the hydraulic oil discharge pipe 16 of the forced opening device to the installed discharge connection port 16a.
7 of the second embodiment, the hydraulic oil in the hydraulic tank 18 is supplied to the front oil chamber, and the hydraulic oil in the rear oil chamber is discharged to the hydraulic tank 18. Since 1 is forcibly opened, the hydraulic pump 17 is stopped when fully opened.
Even if the hydraulic oil supply pipe 14 and the hydraulic oil discharge pipe 16 of the forced opening device are removed from the supply connection port 14a and the discharge connection port 16a after the door body 1 is fully opened, the hydraulic oil Since oil does not flow in the direction from the front oil port 3a to the rear oil port 3b in the first communication pipe 10, the rod 8 of the double-rod hydraulic cylinder 3 cannot be extended and the door 1 is kept open.
Due to a very small amount of hydraulic oil leakage, the opening angle of the upper hinged flap gate will decrease by about 1 to 2 degrees per month, but if the opening angle is set to 20 degrees by forced opening, it will be about 6 degrees. It is possible to maintain a sufficient open state against drainage from upstream for about a month.

Modifications of Examples 1 to 3 are listed.
(1) In Examples 1 to 3, the flow control valve 13 was provided on the rear oil port 3b side of the float valve 4b of the second communication pipe 12, but the flow control valve 13 was provided on the front oil port side of the float valve 4b of the second communication pipe 12. A flow control valve 13 may be provided on the 3a side.
(2) In Examples 1 to 3, an upper hinged flap gate was used. Any gate such as a miter gate may be used as long as it is a moving type gate.

(3) The hydraulic oil supply pipe 14 of Embodiments 2 and 3 connects the hydraulic oil outlet of the hydraulic pump 17 and the front oil port 3a side of the check valve 11 of the first communication pipe 10, but FIG. 2, the hydraulic oil outlet of the hydraulic pump 17 may be connected to the float valve 4b of the second communicating pipe 12 and the front oil port 3a side of the flow control valve 13. As shown in FIG.
The hydraulic oil discharge pipe 16 connects the hydraulic tank 18 and the oil port 3b side behind the check valve 11 of the first communication pipe 10. As shown in FIG. The float valve 4b of the communicating pipe 12 and the rear oil port 3b side of the flow control valve 13 may be connected.
Further, the hydraulic oil supply pipe 14 may be connected as shown in FIG. 6, and the hydraulic oil discharge pipe 16 may be connected as shown in FIG. 9. Conversely, the hydraulic oil supply pipe 14 may be connected as shown in FIG. The hydraulic oil discharge pipe 16 may be connected as shown in FIG.

Reference Signs List 1 door body 1a door body drive arm 2a upstream water channel 2b downstream water channel 3 double rod hydraulic cylinder 3a front oil port 3b rear oil port 4a float 4b float valve 4c float device storage box 5 door stop hardware 6 hinge hardware 7 Trunnion type bearing 8 Rod 9 Tip fitting 10 First communication pipe 11 Check valve 12 Second communication pipe 13 Flow control valve 14 Hydraulic oil supply pipe 14a Supply connection port 15a Supply check valve 15b Check valve with discharge pilot 16 Hydraulic oil discharge pipe 16a Discharge connection port 17 Hydraulic pump 18 Hydraulic tank 19a Upstream water level 19b Downstream water level

Claims (3)

A hydraulic control device for a gate that is closed by its own weight,
A double-rod hydraulic cylinder having a rod, a front oil port and a rear oil port that move in conjunction with the movement of the hydraulic oil,
a door body that moves in a closing direction when the rod moves to the side where the front oil port is provided, and moves in an opening direction when the rod moves to the side where the rear oil port is provided;
a first communication pipe communicating between the front oil port and the rear oil port;
a check valve provided in the first communication pipe and allowing hydraulic oil to flow only in a direction from the rear oil port to the front oil port;
a second communicating pipe communicating between the front side and the rear side of the check valve in the first communicating pipe;
A float valve that is provided in the second communication pipe and opens when the water level downstream of the gate reaches a predetermined water level or higher, and a flow control valve that adjusts the flow rate of hydraulic oil so that it does not exceed a predetermined flow rate. A hydraulic control device characterized by: a hydraulic tank that stores hydraulic oil;
a hydraulic pump that supplies hydraulic oil from the hydraulic tank to the double-rod hydraulic cylinder;
The hydraulic fluid outlet of the hydraulic pump and the front oil port side of the first communicating pipe from the check valve, or the hydraulic fluid outlet and the second communicating pipe to the front oil port side of the float valve and the flow control valve. A hydraulic oil supply pipe connecting the
a supply check valve provided in the hydraulic oil supply pipe;
Hydraulic oil that connects the hydraulic tank and the rear oil port side of the check valve of the first communication pipe or the hydraulic tank and the rear oil port side of the float valve and the flow control valve of the second communication pipe. an exhaust pipe;
a check valve with a discharge pilot provided in the hydraulic oil discharge pipe,
When hydraulic oil is supplied from the hydraulic tank to the double-rod hydraulic cylinder via the hydraulic pump, the hydraulic oil supply pipe, the supply check valve, the first communication pipe, and the front oil port, the Hydraulic oil is discharged from the double-rod hydraulic cylinder to the hydraulic tank through the rear oil port, the first communication pipe, the hydraulic oil discharge pipe, and the discharge pilot check valve. Item 1. The hydraulic control device according to item 1. The hydraulic tank, the hydraulic pump, the hydraulic oil supply pipe, the check valve for supply, the hydraulic oil discharge pipe, and the check valve with pilot for discharge are connected to the first communication pipe or the second communication pipe. 3. The hydraulic control device according to claim 2, wherein the hydraulic control device can be detachably connected to the

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