JP3295191B2 - Hydraulic control for step-actuated lifting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for a step-actuated lifting device capable of using a hydraulic cylinder to lift a lifting body larger than the stroke of the hydraulic cylinder.

[0002]

2. Description of the Related Art Japanese Utility Model Publication No. 61-21603 discloses a fluid cylinder which can be used in such a lifting device. That is, the rod of the cylinder penetrates the piston and penetrates the piston, and the piston and the cylinder each have a lock mechanism that prevents and permits relative movement between the rod and the rod. In this lock mechanism, the plate body into which the rod is inserted is in an unlocked state in which the rod is allowed to move in a normal position where the plate body is positioned by the pressing force of the spring, and a fluid pressure is applied to the plate body to reduce the pressing force of the spring. The plate body is pressed against the outer periphery of the rod in an operating position obtained by swinging the rod against the rod to obtain a locked state in which the rod is prevented from moving. Then, the lock mechanism of the cylinder is unlocked, the lock mechanism of the piston is locked, the piston is moved in one direction, and then the lock mechanism of the piston is unlocked, and the lock mechanism of the cylinder is locked. Repeat the operation to return the piston to the other direction in the state,
The rod is moved stepwise in one direction.

However, when such a fluid cylinder is provided in an upright state and a step-operated lifting device is used to lift a heavy object with a rod, the locking force obtained by pressing the plate against the rod outer periphery is sufficient. It is considered that the rod may be lowered without being used, or a place where the plate body is pressed against the rod may be worn to make it impossible to obtain a locked state. From the viewpoint of ensuring safety, the present inventors have shown an example in FIG. Was adopted in principle.

That is, 1 is a lifting cylinder which fixedly supports the cylindrical body 2 and 3 is an engagement hole 4 which serves as an engagement portion in the vertical direction.
Is a lifting body provided with a plurality. A movable portion 6 provided in connection with the rod 5 of the lifting cylinder 1, and a first receiving member 7 and a second receiving member 8 are provided on a fixed support side of the lifting cylinder 1 for operating the first and second disengaging cylinders. 9 and a second engagement / disengagement cylinder 10.

Each of the cylinders 1, 9, 10 is formed by using two double-acting hydraulic cylinders, and the first and second receiving members 7, 8 are respectively fitted into the engagement holes 4 to move the movable portions 6 or A first engaging member corresponding to a fixed support side of the lifting cylinder 1 corresponding to a position between an engagement position where the load of the lifting body 3 can be received so as not to lower the lifting body 3 and a retracted position separated from the engagement hole 4. The cylinder can be reciprocated by the cylinder 9 or the second cylinder 10. The engagement holes 4 are provided at predetermined intervals.

Then, as shown in FIG.
The rod 5 of the lifting cylinder 1 is lifted from the state in which the first receiving member 7 is located at the engagement position and the second receiving member 8 is located at the retracted position, and the second receiving Since the operation of moving the member 8 to the engagement position and the first receiving member 7 to the retracted position and moving the rod of the cylinder 1 downward again as shown in FIG. is there.

[0007]

However, in this case, if one of the first or second receiving members 7, 8 is moved from the state of receiving the load of the lifting body 3 to the retracted position, the receiving member is stopped. When the other is located at the retracted position, the lifting body 3 falls down to the raised height to cause a dangerous situation, and the other receiving members 8, 7 are inserted into the engagement holes 4. Even in the engaged position, as a result of receiving the load of the lifting body 3,
The engagement hole 4 and the receiving members 8 and 7 are greatly abraded early due to the large friction, and the lifting body 3 cannot be accurately lifted to the initial position, or such abrasion occurs unevenly in each part. There is a problem that the respective receiving members 7, 8 and the engaging holes 4 do not align with each other, so that the receiving members 7, 8 cannot be moved to the engaging position, and the life of the lifting device is shortened.

The present invention is directed to a step-operated lifting device which solves such a problem by preventing the first or second receiving member from being retracted while receiving the load of the lifting member. It is intended to obtain a hydraulic control device.

[0009]

Therefore, in the hydraulic control device according to the first aspect, the first and second engagement / disengagement cylinders operate in the direction of moving the corresponding first or second receiving member to the retracted position. A pressure reducing valve for supplying pressure oil having a pressure smaller than a pressure sufficient to move the receiving member in a state of receiving the load of the lifting body to these engagement / disengagement cylinders is provided in the pressure oil supply path at the time of the operation.

In the hydraulic control apparatus according to the second aspect, the lifting cylinder is supplied with pressure oil to one of the two working chambers and the other is supplied to the tank so that the lifting cylinder is operated in one direction and the other direction. In order to guide and stop the operation, a switching valve is connected to prevent the supply of pressure oil to both working chambers. A flow control valve for measuring and installing a flow control valve for measuring meter-out control is connected in a branched manner, and the second receiving member is brought into the engagement position with the lifting cylinder reaching the operating end in one direction. A switching valve for switching operation to move is connected to the second engagement / disengagement cylinder, and is disengaged to move the first receiving member to the engagement position when the lifting cylinder reaches the operation end in the other direction. An operating switching valve is connected to the first engagement / disengagement cylinder, and an opening / closing valve device is installed in the discharge passage when the lifting cylinder is operated in one direction and is closed when the second receiving member reaches the engagement position. When the one-way operation of the lifting cylinder detects the working chamber pressure on the side to which the hydraulic oil is supplied, and when the pressure changes from low to high, the switching valve connected to the second disengagement cylinder is changed. A pressure detector is provided for switching the switching valve connected to the first disengagement cylinder in response to the change to low so that the corresponding receiving member is moved to the retracted position by each of the disengagement cylinders. .

[0011]

In the hydraulic control device according to the first aspect, when the first and second engagement / disengagement cylinders are operated to move the corresponding first or second receiving member to the retracted position, the first and second engagement / disengagement cylinders are not operated. Since the supplied pressure oil is a pressure smaller than a pressure sufficient to move the receiving member in a state of receiving the load of the lifting body, the engagement / disengagement cylinder operates when the receiving member is in the state of receiving the lifting body. This cannot be moved to the evacuation position, and such movement of the receiving member to the evacuation position is prevented.

In the hydraulic control device according to the second aspect, when the lifting cylinder reaches the operating end in one direction,
The second engagement / disengagement cylinder is operated to move the second receiving member to the engagement position, and the lifting cylinder is stopped with its switching valve switched to the neutral position. When the opening / closing valve device of the discharge passage is opened, the lifting cylinder operates in the other direction, and when the lifting body is slightly lowered, the second receiving member located at the engagement position is engaged with the engagement portion. The load of the lifting body is received by the load of the lifting body, and the load of the lifting body on the first receiving member is eliminated. Then, this situation is detected by the pressure detector as a pressure drop in the working chamber on the side to which the pressurized oil is supplied when the lifting cylinder is operated in one direction, and the detection signal causes the first engagement / disengagement cylinder to operate the first receiving member. Move to the evacuation position.

When the lifting cylinder reaches the working end in the other direction, the first engagement member moves the first receiving member to the engagement position. When the lifting cylinder is actuated in the other direction, the first receiving member engages with the engaging portion to receive the load of the lifting body due to the slight rise of the movable part, thereby lifting the lifting body to the second receiving member. Is eliminated. This situation is detected as a pressure increase by the pressure detector, and the second engagement / disengagement cylinder moves the second receiving member to the retracted position according to the detection signal. In this way, each receiving member is moved from the state of receiving the load of the lifting body to the retreat position after the load is transferred to the other receiving member, and each of the lifting members in the state of receiving the load of the lifting body. Is prevented from being retracted.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is an example in which the step-type lifting device whose configuration is shown in principle in FIG. 1 is embodied, and a duplicate description of the portion previously described in FIG. 1 will be omitted. 11
Is a lower frame forming a fixed support portion, which fixedly supports the cylindrical body 2 of the lifting cylinder 1, and which is appropriately detachably fixed to a base portion (not shown). And
The lower frame 11 and the upper frame 6 serving as a movable portion are provided with through holes 12 and 13 through which the lifting body 3 is inserted. The lifting body 3 has a round bar shape in which the engagement hole 4 is penetrated in the radial direction, and the upper frame 6 and the lower frame 11 have the through holes 1 formed therein.
Guide holes 14, 15 are formed to reach 3, 12,
In these guide holes 14, 15, the first receiving member 7 and the second receiving member 8 are guided, respectively, and the inner ends of the first receiving member 7 and the second receiving member 8 protrude and retreat into the through holes 12, 13, whereby the inner ends are engaged. It is installed so as to be slidable between an engagement position where it is fitted into the hole 4 and a retracted position where it is disengaged from the engagement hole 4. The receiving members 7 and 8 have the same diameter, and the engaging hole 4 has a slightly larger diameter. 16, 17 are the rod 9X of the first engagement / disengagement cylinder 9, the first receiving member 7, and the second
The rod 10X of the engagement / disengagement cylinder 10 and the second receiving member 8
Are connection pieces that connect each other.

Further, as shown in FIG. 3, a limit switch 16 for detecting that the rod 5 of the lifting cylinder 1 has reached the forward working end for raising the upper frame 6, and a retreat for lowering the upper frame 6. Limit switch 17 for detecting the reaching of the working end of the
The second rod 10X reaches the forward working end, so that the second
A limit switch 18 for detecting that the receiving member 8 reaches the retreat position, and a limit switch 19 for detecting that the second receiving member 8 reaches the engaging position by the rod 10X reaching the retreat-side working end, Lower frame 1
1.

Similarly, the upper frame 6 has a first engagement / disengagement cylinder 9
The limit switch 20 detects that the first receiving member 7 reaches the retracted position when the rod 9X reaches the forward operating end, and the first receiving member 7 moves when the rod 9X reaches the retracted operating end. A limit switch 21 for detecting that the engagement position has been reached is provided.

Working chamber 1 on the head side of lifting cylinder 1
A is connected to an electromagnetic switching valve 24 by a flow path 22, and the working chamber 1 B on the rod side is connected to an electromagnetic switching valve 24 by a flow path 23. In the neutral position, the switching valve 24 disconnects the flow paths 22 and 23 from the hydraulic pressure source P to connect to the tank T,
It is a three-position valve having two operating positions for selectively connecting one of the hydraulic pressure sources 2 and 23 to the hydraulic pressure source P and the other to the tank T. Channel 22
, A flow control valve 25 with a built-in check valve serving as a flow control valve for controlling the flow rate of meter-in, a throttle valve 26 with a built-in check valve for controlling the flow rate of the meter-out, and free flow toward the working chamber. A pilot operation check valve 27 is provided, and the check valve 27 is operated by the pilot pressure with the pressure of the flow path 23 to generate a control flow.

Reference numeral 28 denotes a discharge flow passage which is branched from the flow chamber 22A of the flow control valve 25 and connected to the tank T, and a flow control valve 29 serving as a flow control valve for controlling the discharge flow.
And an on-off valve device 32 formed by a pilot operated check valve 30 and an electromagnetic switching valve 31. The check valve 30 has a control flow in the discharge direction, and the electromagnetic switching valve 31 does not form this control flow in the normal position.
A two-position valve that applies pilot pressure to the check valve so as to create a control flow in the operating position. Also, 33
Is a pressure switch which is connected to the working chamber 1A side of the flow control valve 25 in the flow path 22 and serves as a pressure detector for detecting the pressure of the working chamber 1A.

The first engaging / disengaging cylinder 9 is configured such that the working chambers 9A and 9B on the head side and the rod side thereof are formed by flow paths 34 and 35, respectively.
In the second engagement / disengagement cylinder 10, the working chambers 10A and 10B on the head side and the rod side are connected to electromagnetic switching valves 38 and 39 by flow paths 36 and 37, respectively. 40,
Reference numeral 41 denotes a pilot operated check valve installed in the flow paths 34 and 35, which is free flowing in the working chambers 9A and 9B directions.
The control flow is controlled by the pilot pressure from the other flow paths 35 and 34, and similarly, the flow is free in the flow paths 36 and 37 in the direction of the working chambers 10A and 10B. The pilot operation check valves 42 and 43 which become a control flow by the pilot pressure from are provided.

The electromagnetic switching valves 38 and 39 are three-position valves having the same configuration as the electromagnetic switching valve 24,
The pressure reducing valves 44 and 45 are interposed between the pressure reducing valves 44 and 45, respectively. The set pressure of the pressure reducing valves 44 and 45 is controlled by the switching valves 38 and 39 by the engaging and disengaging cylinders 9 and 10, 8 is moved to the evacuation position.
Is smaller than the pressure required to move the receiving members 7 and 8 in the state of receiving the load, so that the receiving members 7 and 8 in the load receiving state cannot be moved.

Next, the operation of this embodiment will be described with reference to FIG. 3 in which the lifting cylinder 1 has the rod 5 at the retreating operation end and the first engagement / disengagement cylinder 9 has the rod 9X at the forward operation end. The second engagement / disengagement cylinder 10 is configured such that the rod 10 </ b> X is located at the retreat-side operating end and the first receiving member 7 lifts the body 3.
Load is received.

Here, when the electromagnetic switching valve 24 is switched to the left position, the lifting cylinder 1 is supplied with pressure oil to the working chamber 1A under meter-in control by the flow regulating valve 25, and is operated forward to operate the upper cylinder. 6 rises with the lifting body 3. At this time, the pressure switch 33 detects the high pressure state of the working chamber 1A and outputs a first signal. When the rod 5 of the lifting cylinder 1 reaches the forward end, the limit switch 16 is operated, and based on a signal from the switch 16, the switching valve 24 is switched to the neutral position to close the pilot operated check valve 27. Then, the lifting cylinder 1 is stopped, and the switching valve 39 is switched to the right position. At this time, in the through hole 12 of the lower frame 11, the stop position of the lifting cylinder 1 is selected so that the engagement hole 4 is aligned coaxially with the second receiving member 8. The second engagement / disengagement cylinder 10 is retracted, the second receiving member 8 is fitted into the engagement hole 4 in the aligned relationship to take the engagement position, and the limit switch 19 is operated.

On the basis of the signal from the operation of the switch 19, the electromagnetic switching valve 39 switches to the neutral position again, and the electromagnetic switching valve 31 switches to the operating position, whereby the pilot operated check valve 30 opens. As a result, the lifting cylinder 1 starts the lowering operation by the load of the lifting body 3 while being subjected to the speed control by the flow control valve 29. As a result, when the lifting body 3 moves down together with the upper frame 6 by a small amount (about 20 mm in this example) corresponding to a radial gap between the second receiving member 8 at the engagement position and the engagement hole 4, The inner surface of the engaging hole 4 abuts and engages with the outer surface of the second receiving member 8, and the second receiving member 8 receives the load of the lifting body 3, and accordingly, the load of the lifting body 3 on the first receiving member 7. Since the load is eliminated, the working chamber 1
The pressure of A decreases, and the pressure switch 33 outputs a second signal in accordance with the decrease in pressure.

In response to the change from the first signal to the second signal by the pressure switch 33, the electromagnetic switching valve 38 is switched to the left position, the first engagement / disengagement cylinder 9 moves forward, and the 1 The receiving member 7 moves to the retracted position, and the limit switch 20 is operated.

In response to the signal from the switch 20, the electromagnetic switching valve 38 is switched to the neutral position, the electromagnetic switching valve 31 is switched to the normal position, the electromagnetic switching valve 24 is switched to the right position, and the lifting cylinder 1 is moved. The upper frame 6 is moved backward while receiving meter-out control by the throttle valve 26. At this time, the lifting body 3 is received by the second receiving member 8 and is kept stopped, and the working chamber 1A
Is lower than when the lifting body 3 is raised, the pressure switch 33 keeps outputting the second signal. Then, when the rod 5 reaches the retreat-side operating end and the limit switch 17 is operated, the electromagnetic switching valve 24
Switches to the neutral position to stop the lifting cylinder 1, and the electromagnetic switching valve 38 switches to the right position. At this time, in the through hole 13 of the upper frame 6, the stop position of the lifting cylinder 1 is selected so that the engagement hole 4 and the first receiving member 7 are coaxially aligned, and the first receiving member 7 is switched. By switching the valve 38, the valve 38 is fitted into the engagement hole 4 in the aligned engagement and moves to the engagement position. In response to this, the limit switch 21 is operated, and in response to a signal from the switch 21, the electromagnetic switching valve 38 switches to the neutral position again.
The electromagnetic switching valve 24 is switched to the left position, and the lifting cylinder 1 starts the forward operation.

As a result, when the upper frame 6 is slightly raised by a distance corresponding to the radial gap between the first receiving member 7 at the engaging position and the engaging hole 4, the outer surface of the first receiving member 7 is
The first receiving member 7 is brought into contact with the inner surface, and the first receiving member 7 is lifted.
, And the load of the lifting body 3 on the second receiving member 8 is eliminated. As a result, the pressure in the working chamber 1A increases, and the output from the pressure switch 33 changes from the second signal to the first signal. This second
The change from the signal to the first signal causes the electromagnetic switching valve 24
Is switched to the neutral position to stop and hold the lifting body 3 together with the upper frame 6, while the electromagnetic switching valve 39 is switched to the left position to operate the second engagement / disengagement cylinder 10 forward and move the second receiving member 8 to the retracted position. Move to

When the second receiving member reaches the retracted position and the limit switch 18 is operated, the electromagnetic switching valve 39 is switched to the neutral position in accordance with the signal from the switch 18, and the electromagnetic switching valve 24 is again switched to the neutral position. The lifting cylinder 3 is moved forward to the left position, and the lifting body 3 is moved forward.
Raise with one.

Thereafter, such an operation is repeated,
The lifting body 3 is raised during the forward operation of the lifting cylinder 1 in which the upper frame 6 is raised, and is raised in a stepwise manner while being stopped during the retreating operation in which the upper frame 6 is lowered, and is lifted. It is.

In this operation, the respective receiving members 7, 8 are moved to the retracted position after the load of the lifting body 3 is transferred to the other receiving members 8, 7, so that a large friction does not occur and the receiving members 7, 8 are smoothly moved. Done. For this reason, the receiving members 7, 8 and the engaging holes 4 are greatly worn out early, and the lifting body 3 cannot be lifted to a correct position, or the receiving members 7, 8 are aligned with the engaging holes 4. It is possible to prevent a situation in which the relationship cannot be obtained and the user cannot move to the engagement position, and the life of the device can be improved.

Since the load transfer to the other receiving members 8 and 7 is performed by detecting the pressure in the working chamber 1A of the lifting cylinder 1, for example, the position of the rod 5 or the upper frame 6 of the lifting cylinder 1 is detected. As compared with the case described above, even when the position at which the load shifts due to wear or the like changes, the shift point can be directly detected, and the load shift is reliably detected.

When one of the receiving members 7 and 8 is in the retracted position and the other is receiving the load of the lifting body 3, the electromagnetic switching is performed so that the receiving member 7 or 8 in the load receiving state is retracted. Valve 38 or 3
Even if 9 is switched to the left position due to a malfunction, the disengagement cylinder 9 or 10 causes the supplied hydraulic oil to be supplied to the pressure reducing valves 44 and 45.
Such receiving member 7 or 8
Cannot move forward to a retreat position because the pressure is not large enough to move the retreat position, and the catching member 7 or 8 does not move to the retreat position.

In this embodiment, each cylinder 1,
The positions of the rods 9, 9 X, 10 X are detected by the limit switches 16, 17, 18, 19, 20, 21. For example, the position of each rod is continuously detected using a potentiometer or the like. A detector that can be used can also be used. The on-off valve device 32 is formed by a pilot-operated check valve 30 and an electromagnetic switching valve 31. As shown in FIG. 4, a two-port switching valve 32A having a poppet-type valve portion is provided by an on-off valve device. Can also be used.

Further, in the embodiment, the lifting cylinder 1
However, it is configured such that the cylindrical body 2 is fixedly supported and the rod 5 is connected to the upper frame 6 which is a movable part so as to move the rod, and the rod 5 is fixedly supported by the rod, and the cylindrical body is used. The upper frame can be used to operate, and each pressure reducing valve 4
The check valves 4 and 45 may be installed in the flow paths 34 and 36 with a built-in check valve mechanism that allows the discharge flow to the tank to flow freely. In addition, although the engaging portion is formed by the engaging hole 4, a notch or a protrusion may be provided as the engaging portion instead. Alternatively, each of the cylinders 1, 9, and 10 may include two hydraulic cylinders. However, the number may be one or three or more as necessary.

[0034]

As described above, according to the first aspect of the present invention, even if the engagement / disengagement cylinder is operated to move the receiving member in the state of receiving the load of the lifting body to the retracted position, the pressure-reducing valve is used. The pressure oil supplied to the engagement / disengagement cylinder is not large enough to move the receiving member in the load receiving state, so the receiving member does not move to the retracted position,
Dangerous situations in which the lifting body falls can be prevented. Also,
According to the invention described in claim 2, each receiving member is
Since the lifting body is moved to the retracted position after the load of the lifting body is transferred to the other receiving member, the engaging portion and the respective receiving portions are not greatly worn early in the retracting operation, and the life is improved, Since the detection of such a transition of the load is performed by detecting the pressure of the working chamber of the lifting cylinder to which the pressure oil is supplied when operating in one direction with a pressure detector, for example, the position of the movable part is detected. As compared with the case where the detection is performed, reliable detection can be performed with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a structural principle diagram showing an example of a step-operated lifting device to which the present invention is directed.

FIG. 2 is a front view showing an example of the embodiment of FIG. 1;

FIG. 3 is a hydraulic circuit diagram showing one embodiment of the present invention.

FIG. 4 is a diagram showing another example of the on-off valve device in FIG. 3 as a symbol.

[Explanation of symbols]

 1 lifting cylinder 2 cylinder 3 lifting body 4 engaging part (engaging hole) 5 rod 6 movable part (upper frame) 7 first receiving member 8 second receiving member 9 first disengaging cylinder 10 second disengaging cylinder 24 , 38, 39 switching valve 25, 29 flow control valve 32 on-off valve device 44, 45 pressure reducing valve

Claims (2)

(57) [Claims] 1. A lifting body provided with a plurality of engaging portions in a vertical direction, and a double-acting hydraulic cylinder arranged upright to fixedly support one of a rod and a cylindrical body and to vertically support the other in a vertical direction. A first receiving member that includes a lifting cylinder provided with a movable portion that reciprocates, engages with an engaging portion to receive a load of the lifting body, thereby preventing the lifting body from lowering relative to the movable portion; A first engagement / disengagement cylinder formed of a hydraulic cylinder for moving the first receiving member between a position where the first receiving member is engaged with the engagement portion and a position retracted therefrom, is disposed on the movable portion, and is engaged with the engagement portion. The second receiving member for receiving the load of the lifting body to prevent the lifting body from lowering relative to the fixed support side of the lifting cylinder, and the second receiving member formed of a double-acting hydraulic cylinder is engaged with the engaging portion. Join And a second engaging / disengaging cylinder that moves between the retracted position and the retracted position is disposed on the fixed support side of the lift cylinder, and the first receiving member is engaged with the engaging portion to retract the second receiving member. The lifting body is raised by operating the lifting cylinder in one direction in the state where the lifting member is placed in the position, and the lifting body is moved in a state where the first receiving member is placed in the retracted position and the second receiving member is engaged with the engaging portion. In a hydraulic control device for a step-actuated lifting device that lifts a lifting body stepwise by alternately repeating an operation of returning a lifting cylinder to another direction while being stopped, a first and second engagement / disengagement cylinders However, in the pressure oil supply path when the corresponding first or second receiving member is moved in the direction of moving to the retracted position, the receiving member in the state of receiving the load of the lifting body is moved. A small pressure hydraulic fluid from the pressure sufficient to dynamic hydraulic pressure control apparatus for a step-operated lifting device, characterized in that it has a pressure reduction valve for supplying to these engaging and disengaging cylinder. 2. A lifting body provided with a plurality of engaging portions in a vertical direction, and a double-acting hydraulic cylinder arranged upright to fixedly support one of a rod and a cylindrical body and to vertically support the other in a vertical direction. A first receiving member that includes a lifting cylinder provided with a movable portion that reciprocates, engages with an engaging portion to receive a load of the lifting body, thereby preventing the lifting body from lowering relative to the movable portion; A first engagement / disengagement cylinder formed of a hydraulic cylinder for moving the first receiving member between a position where the first receiving member is engaged with the engagement portion and a position retracted therefrom, is disposed on the movable portion, and is engaged with the engagement portion. The second receiving member for receiving the load of the lifting body to prevent the lifting body from lowering relative to the fixed support side of the lifting cylinder, and the second receiving member formed of a double-acting hydraulic cylinder is engaged with the engaging portion. Join A second engaging / disengaging cylinder that moves between a position and a position retracted therefrom is disposed on the fixed support side of the lifting cylinder, the first receiving member is engaged with the engaging portion, and the second receiving member is moved to the retracted position. The lifting body is raised by operating the lifting cylinder in one direction in a state where the lifting member is placed, and the lifting body is stopped in a state where the first receiving member is at the retracted position and the second receiving member is engaged with the engaging portion. In a hydraulic control device for a step-actuated lifting device that lifts a lifting body in a stepwise manner by alternately repeating the operation of returning the lifting cylinder to the other direction while keeping the lifting cylinder in one direction, the lifting cylinder has one direction. ,
And a switching valve for supplying pressure oil to one of the two working chambers so as to operate in the other direction and guiding the other to the tank, and for stopping the supply of the pressurized oil to both the working chambers, is connected. A flow control valve for meter-in control is installed in the flow path to which pressure oil is supplied when the lift cylinder is operated in one direction from the switching valve, and a discharge flow path with a flow control valve for meter-out control is branched and connected. When the lifting cylinder reaches the working end in one direction,
A switching valve for performing a switching operation to move the receiving member to the engagement position is connected to the second engagement / disengagement cylinder, and the first receiving member is moved to the engagement position as the lifting cylinder reaches the operating end in the other direction. The switching valve that performs the switching operation is the first
An on-off valve device connected to the engagement / disengagement cylinder, which is closed when the lifting cylinder is operated in one direction and opened when the second receiving member reaches the engagement position, is installed in the discharge passage, and the lifting cylinder is operated in one direction. Sometimes, the working chamber pressure on the side to which the pressure oil is supplied is detected, and when this changes from low to high, the switching valve connected to the second engagement / disengagement cylinder is changed. A step-operated lifting device, comprising a pressure detector for switching a switching valve connected to the first disengagement cylinder so that a corresponding receiving member is moved to a retracted position by each of the disengagement cylinders. Hydraulic control device for equipment.