JP2002020082A - Hook storage device and surge pressure prevention method in hook storage for crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent large tension from applying to a wire rope in storage of a hook. SOLUTION: This hook storage device of a crane comprises a bypass circuit 16 connected between a pump passage 13 connected through a winch switchover valve 30 to a winch hydraulic motor 5 and a tank passage 15 after bypassing the winch switchover valve 30 and having a differential pressure regulating valve 17 installed therein, a high-pressure relief valve 19 installed in the vent passage 18 of the differential pressure regulating valve 17, a low-pressure relief valve 21 installed in the vent passage 18 connected between the vent passage 18 and the tank passage 15 and opening in the storage of a hook when the valve is normally closed, a first solenoid valve 24 connected to the vent passage parallel with the low-pressure relief valve 21 and closed in the storage of the hook when the valve is normally open, and a second solenoid valve 25 connected to the vent passage in series with the low-pressure relief valve 21 and opening in the storage of the hook the valve is normally closed. The second solenoid valve 25 is closed later than the first solenoid valve 24 after the hook is stored, whereby the instantaneous rise of a hydraulic motor driving pressure in the storage of the hook can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane hook storing technique for automatically storing a hook suspended at a lower end of a wire which is wound up and down by a winch, for example, mounted on a truck. The present invention relates to a technology effective for use in a crane hook storage device.

[0002]

2. Description of the Related Art In a crane mounted on a truck, a hook storage device of a crane for storing a hook in a storage portion at a tip of a boom in order to prevent a hook suspended from a tip of a wire from swinging during traveling. Is equipped.

[0003] In the conventional crane hook storage device, when the crane wire is wound up to the upper limit by a winch, the hook comes into contact with the overwind prevention switch and the overwind prevention switch is activated. The energization of the solenoid valve and the third solenoid valve is turned off, and the winch switching valve is returned to the neutral position to prevent overwinding of the wire rope. Here, the configuration of a conventional crane hook storage device will be described with reference to FIG. Note that the reference numerals in parentheses correspond to those in FIG. That is, the hook storage device of the crane includes a pump passage (13) connected to a pump (12), a tank passage (15) connected to a tank (14), the pump passage (13) and the tank passage ( 15) The supply / discharge passages (5A, 5B) of the hydraulic motor (5) of the winch (6) connected to the winch (6) via the winch switching valve (30), and the winch switching valve (30) of the pump passage (13). A bypass passage (16) connected to the tank passage (15) bypassing the winch switching valve (30) upstream of the winch switching valve (30), and a difference that is provided in the bypass passage (16) and operated by controlling the pilot pressure. Pressure valve (17) and this differential pressure valve (1
7) a high-pressure relief valve (19) provided in a vent circuit (18), and a branch from the differential pressure valve (17) and the high-pressure relief valve (19) in the vent circuit (18); A vent passage (20) connected to the tank passage (15), a low pressure relief valve (21) provided in the vent passage (20), and a low pressure relief valve (21) in the vent passage (20); A detour passage (22) connected in parallel, a first solenoid valve (24) interposed in the detour passage (22) that is normally open and closed during crane normal operation and hook retracting operation, and the vent passage ( 20) A second solenoid valve (25) which is disposed closer to the low-pressure relief valve (21) than the bypass passage (22) in series with the low-pressure relief valve (21) and is normally closed and opened when the hook is retracted. And When the wire (7) of the crane is wound up to the upper limit by the winch (6), the hook (8) comes into contact with the overwind prevention switch (42), and the overwind prevention switch (42) is activated, and the switch is operated. The activation signal causes the controller (40) to operate the first solenoid valve (24).
The energization of the wire rope is turned off to stop the drive of the hydraulic motor (5), thereby preventing the wire rope (7) from being overwound. When the hook storage switch (41) is turned on in this state, the controller (40) energizes the first solenoid valve (24) and the second solenoid valve (25) to switch each solenoid valve, and the hydraulic motor ( 5) is driven by the low pressure (weak force) set by the low pressure relief valve (21) so that the hook (8) is bent under the boom (4) as shown by the solid line in FIG. It is designed to be stored.

[0004]

In the hook storage device of the crane described above, after the hook reaches the position for activating the overwinding prevention switch and the hook is stopped, the hook storage operation button is pressed to bend the hook and store it. When the operation is completed and the operation of the button is stopped, the operating pressure of the winch is instantaneously changed to the set pressure of the high-pressure relief valve (a valve for setting the normal operating pressure of the winch) due to the operation delay of the solenoid valve of the control circuit. A so-called surge pressure that rises may generate a load on the wire.

An object of the present invention is to provide a hook storage device of a crane and a method of preventing a surge pressure when the hook is stored, which can prevent a load from being applied to a wire when the storage of the hook is completed.

[0006]

A first means for solving the above-mentioned problems is to provide a pump passage connected to a pump, a tank passage connected to a tank, and a winch switch to the pump passage and the tank passage. A supply / discharge passage of a winch hydraulic motor connected via a valve, a bypass passage connected to a tank passage bypassing the winch switching valve upstream of the winch switching valve in the pump passage, and a bypass passage connected to the bypass passage. A differential pressure valve interposed in a passage and operated by control of pilot pressure, a high pressure relief valve interposed in a vent circuit of the differential pressure valve, and a branch from between the differential pressure valve and the high pressure relief valve in the vent circuit. A vent passage connected to the tank passage, a low-pressure relief valve interposed in the vent passage, and a low-pressure relief valve parallel to the vent passage. A connected detour passage, a first solenoid valve interposed in the detour passage that is normally open and closed during crane normal operation and hook storage operation, and closer to the low-pressure relief valve than the detour passage in the vent passage. A second solenoid valve that is normally closed and opened at the time of hook retracting operation interposed in series with the low-pressure relief valve, and the second solenoid valve is configured to perform a closing operation after the hook retracting operation.
The first electromagnetic valve is configured to be closed later than the opening operation of the first electromagnetic valve.

[0007] The second means for solving the above-mentioned problem is:
The delayed closing operation of the second solenoid valve is performed under the control of a controller.

[0008] A third means for solving the above-mentioned problem is:
A pump passage connected to a pump, a tank passage connected to a tank, a supply / discharge passage for a hydraulic motor of a winch connected to the pump passage and the tank passage via a winch switching valve, and a supply passage for the pump passage. A bypass passage connected to a tank passage bypassing the winch switching valve upstream of the winch switching valve, a differential pressure valve interposed in the bypass passage and operated by controlling pilot pressure, and a vent circuit of the differential pressure valve A high-pressure relief valve interposed in the vent circuit, a vent passage branched from between the differential pressure valve and the high-pressure relief valve in the vent circuit and connected to the tank passage, and a low-pressure relief interposed in the vent passage. A valve, a bypass passage connected to the vent passage in parallel with the low-pressure relief valve, and a normally opened clay provided in the bypass passage. A first solenoid valve that is closed during normal operation and during hook storage operation; and a normally closed valve that is provided in series with the low pressure relief valve closer to the low pressure relief valve than the bypass passage in the vent passage, and opens during hook storage operation. A second solenoid valve, a controller for controlling the first solenoid valve and the second solenoid valve, and a hook storage operation switch for storing a hook, wherein the controller turns off the hook storage operation switch. When the opening operation of the first solenoid valve is completed, the second solenoid valve is controlled to be closed.

A fourth means for solving the above-mentioned problem is:
A pump passage connected to a pump, a tank passage connected to a tank, a supply / discharge passage for a hydraulic motor of a winch connected to the pump passage and the tank passage via a winch switching valve, and a supply passage for the pump passage. A bypass passage connected to a tank passage bypassing the winch switching valve upstream of the winch switching valve, a differential pressure valve interposed in the bypass passage and operated by controlling pilot pressure, and a vent circuit of the differential pressure valve A high-pressure relief valve interposed in the vent circuit, a vent passage branched from between the differential pressure valve and the high-pressure relief valve in the vent circuit and connected to the tank passage, and a low-pressure relief interposed in the vent passage. A valve, a bypass passage connected to the vent passage in parallel with the low-pressure relief valve, and a normally opened clay provided in the bypass passage. A first solenoid valve that is closed during normal operation and during hook storage operation; and a normally closed valve that is provided in series with the low pressure relief valve closer to the low pressure relief valve than the bypass passage in the vent passage, and opens during hook storage operation. A second solenoid valve, a cylinder device for switching and driving the winch switching valve, and a hoisting port of the cylinder device connected to the tank passage at normal times to switch the winch switching valve to the neutral position, and to perform a hoisting operation when a hoisting operation command is issued. A third solenoid valve that connects a side port to the pump passage to switch the winch switching valve to a winding position, and the first solenoid valve,
A controller for controlling the second solenoid valve and the third solenoid valve, and a hook storage operation switch for storing a hook, wherein the controller is configured to control the third storage when the hook storage operation switch is turned off. After canceling the command of the winding operation of the solenoid valve and switching the winch switching valve to the neutral position, control is performed such that the first solenoid valve is closed and operated.

According to the first to third means, when the hand is released from the hook storage operation switch after the hook storage operation, the second solenoid valve closes later than the opening operation of the first solenoid valve. No high pressure operation and no surge pressure. Therefore, a large load is not applied to the wire.

According to the above-mentioned fourth means, when the hand is released from the hook storage operation switch, the command for the winding operation of the third solenoid valve is released and the winch switching valve is returned to the neutral position. Since one solenoid valve is closed and operated, no surge pressure is generated. Therefore, no heavy load is applied to the wire.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the crane hook storage device according to the present embodiment is mounted on a crane 2 mounted on a truck 1. The crane 2 has a post 3 erected between the operator's cab of the truck 1 and a cargo bed, and a rear end of a telescopic boom 4 is pivotally supported on the upper end of the post 3 so as to rotate. I have. A winch 6 driven by a hydraulic motor 5 is provided in an upper end portion of the post 3, and the winch 6 feeds out and winds a wire 7 stretched on a boom 4. A hook 8 is suspended from the tip of the wire 7 via a pulley. When the hook 8 comes into contact with the weight 42A hanging from the overwind prevention switch 42, the overwind prevention switch 42 is activated,
Winding of the winch is stopped. Here, when the hook storage operation switch 41 is pressed, the hook 8 is wound up again by a weak force described later. However, when the block of the pulley of the hook 8 contacts the hook storage member 9, the hook storage member 9 is used as a fulcrum. It is stored under the boom 4 as if it were bent.

A crane 2 mounted on a truck 1 shown in FIG.
Is driven by a hydraulic system, and a hydraulic circuit of an operation device (hereinafter, referred to as an operation device) 10 for operating the crane 2 is configured as shown by a reference numeral 11 in FIG. That is, the hydraulic circuit 11 of the operating device 10
A pump passage 13 to which pressure oil is supplied from
And a tank passage 15 connected to the tank. A winch switching valve 30 is provided between the pump passage 13 and the tank passage 15.
The winch switching valve 30 supplies pressure oil to a hydraulic motor 5 that drives the winch 6, or
The supply / discharge passages 5A and 5B for discharging are connected. In addition, switching valves for crane expansion / contraction, undulation, turning, etc. are omitted.

A bypass passage 16 is connected upstream of the winch switching valve 30 of the pump passage 13 to bypass the winch switching valve 30 and communicate with the tank passage 15. The bypass passage 16 is controlled by pilot pressure. An operating differential pressure valve 17 is provided. The vent circuit 18 of the differential pressure valve 17 is connected to the tank passage 15, and a high-pressure relief valve 19 which is normally closed is interposed in the vent circuit 18. The high-pressure relief valve 19 is configured to open when the pressure of the vent circuit 18 becomes higher than the maximum working pressure (for example, 19.6 MPa) of a winch or other actuator.

A vent passage 20 branches from the differential pressure valve 17 and the high pressure relief valve 19 of the vent circuit 18, and the other end of the vent passage 20 is connected to the tank passage 15. In the middle of the vent passage 20, a low-pressure relief valve 21
The low-pressure relief valve 21 is connected to the vent passage 2.
0 is the maximum pressure when the hook is retracted (for example, 3.92
(MPa) or more.

A bypass passage 22 is connected to the vent passage 20 in parallel with the low-pressure relief valve 21 so as to bypass the low-pressure relief valve 21. The bypass passage 22 is provided with a two-port, two-position, electromagnetically operated switching valve. The configured first solenoid valve 2
4 is provided via a cock valve 23. The first solenoid valve 24 is mechanically constituted by a poppet valve,
It is opened at normal times and closed at the time of commanding the normal operation of the crane and the hook storage operation.

A second solenoid valve 25 composed of a two-port, two-position, electromagnetically operated switching valve is provided in series with the low-pressure relief valve 21 in the vent passage 20 closer to the low-pressure relief valve 21 than the bypass passage 22. ing. Second solenoid valve 2
Numeral 5 is mechanically constituted by a spool valve, which is closed during normal operation and opened when a command to store the hook is issued.

As shown in FIG. 2, the winch switching valve 3 for switching the winch 6 between hoisting and lowering.
Reference numeral 0 denotes a cylinder device 31 driven by a wireless remote control (hereinafter, referred to as a remote controller), which will be described later, or is operated by a manual operation. ) And switching positions on both sides thereof (similarly, suffixes b and c are added). The pump passage 13 is connected to the pump port of the winch switching valve 30, the tank passage 15 is connected to the tank port, and the supply / discharge passages 5A and 5B of the hydraulic motor 5 are connected to the two load ports. That is, the hydraulic motor 5 of the winch 6 is positioned at the position 3 of the winch switching valve 30.
b so as to wind up the wire 7 of the winch 6
At a position 3c, the wire 7 rotates so as to wind down.

The winch switching valve 30 includes a winch switching valve 3
The cylinder device 31 for driving the zero is connected in series. The cylinder device 31 has a cylinder chamber 32 in which a piston 33 is slidably fitted. The piston rod 34 connected to the spool of the winch switching valve 30 is inserted along the axis of the cylinder chamber 32 and is slidably supported. In FIG. 2, the winch switching valve 30 and the cylinder device 31 are connected via a piston rod 34, but the piston rod 34 is omitted and the winch switching valve 30 and the cylinder device 31 are integrally formed. May be.

The hoisting side port 35 opened at the end of the cylinder chamber 32 on the winch switching valve 30 side has three ports.
The load port of the third solenoid valve 26 constituted by a two-position, pilot offset, solenoid operated switching valve is connected. The pump port of the third solenoid valve 26 is the pump passage 1
3 and the tank port is connected to the tank passage 15. The third solenoid valve 26 is mechanically constituted by a poppet valve, and normally the load port is connected to the tank passage 15 to position the winch switching valve 30 at the neutral position 30a. The winch switching valve 30 is connected to the pump passage 13 to be switched to the winding position 30b.

A lowering port 36 opened at an end of the cylinder chamber 32 opposite to the winch switching valve 30 has a fourth solenoid valve constituted by a 3-port 2-position pilot-offset solenoid operated switching valve. 27 load ports are connected. The pump port of the fourth solenoid valve 27 is connected to the pump passage 13, and the tank port is connected to the tank passage 15. The fourth solenoid valve 27 is mechanically constituted by a poppet valve, and normally has a load port connected to the tank passage 15 to position the winch switching valve 30 at the neutral position 30a. Is connected to the pump passage 13 and the winch switching valve 3
0 is switched to the lowering position 30c.

The solenoids of the first solenoid valve 24, the second solenoid valve 25, the third solenoid valve 26, and the fourth solenoid valve 27 are controlled by a controller 40 constituted by a microcomputer or the like. . A hook storage operation switch 41 is connected to the controller 40. Further, an overwind prevention switch 42 and a remote control antenna 43 are connected. When an operation signal is input to the controller 40 from the hook storage operation switch 41, the overwind prevention switch 42, or a remote control transmitter (not shown) via the remote control antenna 43, the controller 40 sets the first electromagnetic valve 24, A signal is sent to one of the two solenoid valves 25, the third solenoid valve 26, and the fourth solenoid valve 27, which is necessary for the commanded operation.

The operating device 10 vertically moves a hydraulic cylinder device for extending and retracting the boom 4, a hydraulic cylinder device for raising and lowering the boom 4, a hydraulic motor for rotating the boom 4 right and left, and an outrigger. Hydraulic jack for the operating device 10
1, these switching valves are also provided, respectively, but their illustration and description are omitted. 44 is a back pressure valve for generating a constant oil pressure required for driving the remote control cylinder device 31, 45 is a pressure reducing valve, 46 is a relief valve, 47 is a filter, and 48 is for when the filter 47 is clogged. Is a filter relief valve.

The operation and effect of the crane hook storage device according to the above configuration will be described. FIG. 4 shows a flowchart at the time of the hook storing operation.
Indicates each step of the flowchart.

In FIG. 2, when a signal for raising the winch 6 is transmitted from a remote control transmitter (not shown), the antenna 4
3, the controller 40 sends a signal to the first solenoid valve 24 and the third solenoid valve 26, switches the first solenoid valve 24 from open to closed, and moves the third solenoid valve 26 to the arrow A Switch to the direction indicated by.

When the third solenoid valve 26 is switched, the winch switching valve 30 is switched to the winding position 30b, so that the pressure oil in the pump passage 13 is supplied to the hydraulic motor 5 through the supply / discharge passage 5A, and the hydraulic motor 5 The wire 7 is wound by rotating the wire 6 in the winding direction.

When the hook 8 comes into contact with the weight 42A of the overwind prevention switch 42 near the tip of the boom 4 by winding the wire 7 of the winch 6, the overwind prevention switch 42 is turned on, and the controller 40 operates the first solenoid valve. 24
And the energization to the third solenoid valve 26 is stopped. For this reason,
The winch switching valve returns to the neutral position, the hydraulic motor 5 stops, and the winding of the winch 6 also stops (S1, S in FIG. 4).
2).

When the hook storage operation switch 41 is turned on to store the hook 8, the controller 40 energizes the first solenoid valve 24, the second solenoid valve 25, and the third solenoid valve 26, and is shown in FIG. Are switched (S3 to S5 in FIG. 4). That is, the first solenoid valve 24 is switched from open to closed, the second solenoid valve 25 is switched from closed to open, the third solenoid valve is switched in the direction indicated by arrow A, and the winch switching valve 30 is switched by arrow B. Switch to the indicated direction. When the second solenoid valve 25 is opened, the pressure oil in the vent passage 20 flows through the low-pressure relief valve 21, thereby causing the differential pressure valve 17, that is, the bypass passage 1.
The pressure oil set by the low-pressure relief valve 21 flows through 6.
Therefore, the low pressure oil set by the low pressure relief valve is also supplied to the hydraulic motor 5, so that the drum 6 is wound up with a small force, and the hook 8 is moved from the state shown by the two-dot chain line in FIG. Boom 4 as shown in
Is stored in a shape that is bent below (S6-
S7).

The first solenoid valve 24, the second solenoid valve 2
When the power supply to the fifth solenoid valve 26 and the third solenoid valve 26 is stopped at the same time, a difference occurs in the time required to return to the neutral position due to the difference in the structure of the first solenoid valve 24, the second solenoid valve 25 and the third solenoid valve 26. However, since the switching may be performed in the order of the second solenoid valve 25 → the first solenoid valve 24 → the third solenoid valve 26, the moment when both the first solenoid valve 24 and the second solenoid valve 25 are closed for a moment. Occurs. When both the first solenoid valve 24 and the second solenoid valve 25 are closed, the relief pressure set by the high pressure relief valve 19 is attained. Further, since the winch switching valve 30 switched by the third solenoid valve 26 has not returned to the neutral position, the pressure of the supply / discharge passage 5A of the hydraulic motor 5 surges, and the pressure of the high pressure relief valve 19 is momentarily set to the set pressure. Become.
As a result, a large torque is generated in the hydraulic motor 5 and a large tension acts on the wire 7.

However, in the hook storage device of the crane according to the present embodiment, the time when the second solenoid valve 25 switches from open to closed as shown in FIG.
Since it is delayed from the time when the switch 4 is switched from the closed state to the open state, generation of a large torque in the hydraulic motor 5 is prevented, and as a result, a large tension is applied to the wire 7.

That is, when the hook storage operation switch 41 is turned on (S4), as shown in FIG. 3D, the pressure of the pump port of the winch switching valve 30 starts to increase from the unloading pressure P1. When the hydraulic motor operating pressure P2 at which the hydraulic motor 5 operates is reached, the winch 6 is rotated, the wire is wound up, and the hook is retracted.

As shown in FIG. 3E, when the block of the hook 8 comes into contact with the hook-in member 9 and the hook is stored as shown by a solid line in FIG.
As shown in (d), the pressure at the pump port of the winch switching valve 30 rises from the hydraulic motor operating pressure P2 to the set pressure P3 of the low pressure relief valve 21, and the pressure P3
Is maintained.

As shown in FIG. 3A, when the hook storage operation switch 41 is turned off (S8), the state shown in FIG.
As shown in (b), the first solenoid valve 24 switches from the closed state to the open state because the power supply from the controller 40 is cut off (S9 in FIG. 4). At this time, as shown in FIG. 3C, the second solenoid valve 25 is kept on by the controller 40 and is turned off after a predetermined time (20 ms) (S10 in FIG. 4). Therefore, as shown in FIG. 3D, the pressure of the pump port of the winch switching valve 30 instantaneously drops from the set pressure P3 of the low-pressure relief valve 21 to the unloading pressure P1. That is, a large torque does not act on the hydraulic motor 5 after the hook storing operation is completed.

In FIG. 2, the hook storage operation switch 4
When the solenoid of the first solenoid valve 24 is turned off at the same time as the turning-off of 1, the first solenoid valve 24 opens the bypass passage 22, so that the pressure of the pump port becomes an unloading state. That is, the pressure of the pump port of the winch switching valve 30 falls to the unloading state without increasing in a surge manner.

As described above, according to the present embodiment, the closing operation of the second solenoid valve 25 at the time of the hook storage operation is delayed from the opening operation of the first solenoid valve 24 at the time of the hook storage operation. Since it is possible to prevent a large torque from being generated in the hydraulic motor 5, it is possible to prevent a large tension from acting on the wire 7.

Second solenoid valve 25 during hook retracting operation
By delaying the closing operation of the crane by the controller 40, it is not necessary to modify the hardware of the crane hook storage device, so that it is possible to prevent an increase in the manufacturing cost of the crane hook storage device and the entire crane.

It should be noted that the present invention is not limited to the above-described embodiment, but may be modified without departing from the scope of the invention.
It goes without saying that various changes can be made.

For example, the closing operation of the second solenoid valve 25 at the time of the hook retracting operation is not limited to be configured to be delayed by the controller 40, but may be configured to be delayed by an electric delay circuit. It may be delayed mechanically.

The first solenoid valve 24 and the second solenoid valve 2
5 may be switched after the third solenoid valve 26 switches, that is, after the winch switching valve 30 has completely returned to the neutral position. If the winch switching valve 30 is completely returned to the neutral position, no surge pressure is generated in the hydraulic circuit by switching the first solenoid valve 24 or the second solenoid valve 25.

[0041]

As described above, according to the present invention,
It is possible to prevent a large torque from being generated in the winch during the hook retracting operation, and to prevent a load from being applied to the wire.

[Brief description of the drawings]

FIG. 1 is a side view showing an external appearance of a truck crane having a crane hook storage device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a hydraulic circuit of a crane operating device.

FIG. 3 is a diagram showing a relationship between a hook storage operation switch and an opening / closing timing of an electromagnetic valve, a relationship between a pressure at a valve inlet, a movement amount of a hook, and the like.

FIG. 4 is a flowchart showing a hook storing operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Truck, 2 ... Crane, 3 ... Post, 4 ... Boom, 5 ... Hydraulic motor, 5A, 5B ... Supply / discharge passage, 6 ... Winch, 7 ... Wire, 8 ... Hook, 9 ... Hook storage member,
10 operating device, 11 hydraulic circuit, 12 pump, 13
... Pump passage, 14 ... Tank, 15 ... Tank passage, 16
... bypass passage, 17 ... differential pressure valve, 18 ... vent circuit, 1
9 high-pressure relief valve, 20 vent path, 21 low-pressure relief valve, 22 bypass path, 23 cock valve, 24 first electromagnetic valve, 25 second electromagnetic valve, 26 third electromagnetic valve, 27
... 4th solenoid valve, 30 ... winch switching valve, 30a ... neutral position, 30b ... winding position, 30c ... lowering position, 3
DESCRIPTION OF SYMBOLS 1 ... Winch switching valve drive cylinder device, 32 ... Cylinder chamber, 33 ... Piston, 34 ... Piston rod, 35 ...
Hoisting side port, 36 ... Unwinding side port, 40 ... Controller, 41 ... Hook storage operation switch, 42 ... Overwind prevention switch, 42A ... Weight, 43 ... Remote control antenna, 44 ... Back pressure valve, 45 ... Pressure reducing valve, 46 ... Relief valve, 47 ... Filter, 48 ... Relief valve for filter.

Continued on the front page (72) Inventor Masayoshi Akita 5405-3 Shido, Shido-cho, Okawa-gun, Kagawa Prefecture F-term in Tadano Co., Ltd. 3F204 AA01 BA02 CA05 FA07 FB01 FC08 GA01 3F205 AA06 AC01 BA06 CA03 JA10

Claims (4)

[Claims] A pump passage connected to a pump, a tank passage connected to a tank, a supply / discharge passage for a hydraulic motor of a winch connected to the pump passage and the tank passage via a winch switching valve, A bypass passage connected to a tank passage bypassing the winch switching valve upstream of the winch switching valve in the pump passage; a differential pressure valve interposed in the bypass passage and operated by controlling pilot pressure; A high pressure relief valve interposed in a vent circuit of the differential pressure valve, a vent passage branched from between the differential pressure valve and the high pressure relief valve in the vent circuit and connected to the tank passage; A low pressure relief valve provided, a bypass passage connected to the vent passage in parallel with the low pressure relief valve, and a normal time intervening in the bypass passage. A first solenoid valve that is opened and closed during normal operation of the crane and during the retracting operation of the hook, and a hook that is normally closed and hooked in series with the low-pressure relief valve closer to the low-pressure relief valve than the bypass passage in the vent passage. A second solenoid valve that opens during the storage operation, wherein the second solenoid valve is configured to close at a later time than the opening operation of the first solenoid valve during the closing operation after the hook storage operation. Crane hook storage device. 2. The crane hook storage device according to claim 1, wherein the delayed closing operation of the second solenoid valve is performed under the control of a controller. A pump passage connected to the pump, a tank passage connected to the tank, a supply / discharge passage for a winch hydraulic motor connected to the pump passage and the tank passage via a winch switching valve, A bypass passage connected to a tank passage bypassing the winch switching valve upstream of the winch switching valve in the pump passage; a differential pressure valve interposed in the bypass passage and operated by controlling pilot pressure; A high pressure relief valve interposed in a vent circuit of the differential pressure valve, a vent passage branched from between the differential pressure valve and the high pressure relief valve in the vent circuit and connected to the tank passage; A low pressure relief valve provided, a bypass passage connected to the vent passage in parallel with the low pressure relief valve, and a normal time intervening in the bypass passage. A first solenoid valve that is opened and closed during normal operation of the crane and during the retracting operation of the hook, and a hook that is normally closed and hooked in series with the low-pressure relief valve closer to the low-pressure relief valve than the bypass passage in the vent passage. A second solenoid valve that opens when the storage operation is performed, a controller that controls the first solenoid valve and the second solenoid valve, and a hook storage operation switch for storing the hook,
When the hook storage operation switch is turned off, the controller controls the second electromagnetic valve to be closed and operated after the opening operation of the first electromagnetic valve is completed. Surge pressure prevention method. 4. A pump passage connected to a pump, a tank passage connected to a tank, a supply / discharge passage for a hydraulic motor of a winch connected to the pump passage and the tank passage via a winch switching valve, A bypass passage connected to a tank passage bypassing the winch switching valve upstream of the winch switching valve in the pump passage; a differential pressure valve interposed in the bypass passage and operated by controlling pilot pressure; A high pressure relief valve interposed in a vent circuit of the differential pressure valve, a vent passage branched from between the differential pressure valve and the high pressure relief valve in the vent circuit and connected to the tank passage; A low pressure relief valve provided, a bypass passage connected to the vent passage in parallel with the low pressure relief valve, and a normal time intervening in the bypass passage. A first solenoid valve that is opened and closed during normal operation of the crane and during the retracting operation of the hook, and a hook that is normally closed and hooked in series with the low-pressure relief valve closer to the low-pressure relief valve than the bypass passage in the vent passage. A second solenoid valve that opens during the retracting operation, a cylinder device that switches the winch switching valve, and a winding port of the cylinder device that is normally connected to the tank passage during normal operation to switch the winch switching valve to the neutral position, thereby performing a winding operation. A third solenoid valve for connecting a hoisting port to the pump passage at the time of a command to switch the winch switching valve to the winding position, a controller for controlling the first solenoid valve, the second solenoid valve and the third solenoid valve, and a hook; And a hook storage operation switch for storing the hook. When the winch switching valve is switched to the neutral position after canceling the hoisting operation command of the third solenoid valve, the first solenoid valve is controlled to be closed, and the crane hook is stored. How to prevent surge pressure at the time.