WO2016092719A1

WO2016092719A1 - Crane operating device

Info

Publication number: WO2016092719A1
Application number: PCT/JP2015/004168
Authority: WO
Inventors: 久雄玉井; 末和郷東
Original assignee: 株式会社タダノ
Priority date: 2014-12-09
Filing date: 2015-08-20
Publication date: 2016-06-16
Also published as: CN107001013A; JP6520092B2; KR101960207B1; KR20170081674A; JP2016108133A; CN107001013B

Abstract

Provided is a crane operating device with good work efficiency that operates quickly even during hook storing operations until a hydraulic actuator reaches an overwind state. A crane operating device comprises: an overwind detector (28) that detects an overwind state for a hook (24); a winch hydraulic actuator (32); a hook storage switching control valve (44) that switches the direction of hydraulic fluid supplied to the winch hydraulic actuator (32); and a relief circuit (50) that sets a circuit pressure. The relief circuit (50) sets the circuit pressure to be high when the overwind detector (28) does not detect the overwind state and sets the circuit pressure to be low when the overwind detector (28) detects an overwind state and the hook storage switching control valve (44) is switched to a lift winding position. Because the circuit pressure is set to be high when the hook (24) is not in an overwind state, operability is good and the hydraulic actuator operation is fast until the overwind state is reached even during hook storing operations.

Description

Crane operating device

The present invention relates to a crane operating device. More specifically, the present invention relates to a crane operating device capable of performing a hook storing operation in which a hook is stored in contact with a boom.

Patent Document 1 discloses a crane hook operating device. This hook operating device is provided with a hook storing switching valve separately from the winch switching valve as a switching valve for switching the operation of the winch motor. During crane operation, the hook is wound up and down by operating the winch switching valve. On the other hand, at the time of hook storage work, the hook is wound up and stored by operating the hook storage switching valve.

Also, the hook operating device is provided with an unloading valve that allows the hydraulic oil in the main pipeline to escape to the tank when the hook is overwound. When the distance between the lower part of the tip of the boom and the upper part of the hook reaches a predetermined length or less, the hoisting of the hook, the extension of the boom, and the raising of the boom are stopped. It is configured to prevent collision with the hook.

When storing the hook, it is necessary to wind the hook further from the overwind state. Accordingly, the hook storage switching valve is operated so that the hook can be wound up even in the overwind state.

A storage relief valve is provided between the return line and the storage line connected from the hook storage switching valve to the winch motor winding line. The storage relief valve is set to a pressure lower than that of the main relief valve, and is configured so that the hook and the tip of the boom are not damaged when the hook comes into contact with the tip of the boom.

Usually, the hook storage operation is performed by operating the hook storage switching valve instead of the winch switching valve to wind and store the hook. This is because if the hook is wound up by operating the winch switching valve, the hook is turned over and the hook is stopped. Usually, the hook storing operation not only stores the hook, but also retracts the boom and retracts the boom to store the boom. Therefore, simultaneously with the hook winding operation, the boom is contracted and laid down.

However, if the switching valve for hook storage is operated, the circuit pressure is reduced by the storage relief valve regardless of whether the hook is in an overwound state or not. Therefore, there is a problem that the operation of the hydraulic actuator becomes slow, the operability is poor, and it takes time to store the hook.

JP 2001-31375 A

In view of the above circumstances, an object of the present invention is to provide a crane operating device in which the hydraulic actuator operates quickly and has good workability until it is overwound even during hook storage.

A crane operating device according to a first aspect of the present invention is a crane operating device comprising a boom and a hook suspended from the boom, the overwinding detector detecting the overwinding state of the hook, and operating the crane A hydraulic circuit for operating the winch for hoisting and lowering the hook, a hook storage switching control valve for switching the direction of hydraulic oil supplied to the hydraulic actuator for the winch, and a circuit pressure. A relief circuit that sets the circuit pressure to a high pressure when the overload detector does not detect the overwind state, and the overload detector detects the overwind state. When the detection is performed and the hook storage switching control valve is switched to the hoisting position, the circuit pressure is set to a low pressure.
The crane operating device according to a second aspect is the crane according to the first aspect, wherein the hydraulic circuit includes a winch switching control valve for switching a direction of hydraulic oil supplied to the hydraulic actuator for the winch, and the relief circuit detects the overwind detection. The circuit pressure is set to the unload pressure when the winder detects the overwind state and the winch switching control valve is switched to the hoisting position.
The crane operating device according to a third aspect is the first aspect, wherein the relief circuit includes a relief main valve provided between a main oil passage and a return oil passage, a back pressure pilot port of the relief main valve, A high pressure pilot oil passage connecting the return oil passage, a low pressure pilot oil passage connecting the back pressure pilot port of the relief main valve and the return oil passage, and a high pressure provided in the high pressure pilot oil passage A relief child valve, a low-pressure relief child valve provided in the low-pressure pilot oil passage, a low-pressure pilot oil passage provided in the low-pressure pilot oil passage, wherein the over-winding detector detects a winding state, and the hook And a low-pressure switching control valve for communicating the low-pressure pilot oil passage when the storage switching control valve is switched to the hoisting position.
The crane operating device according to a fourth aspect of the present invention is the crane according to the first aspect, wherein the relief circuit includes a relief main valve provided between a main oil passage and a return oil passage, a back pressure pilot port of the relief main valve, A high pressure pilot oil passage connecting the return oil passage, a low pressure pilot oil passage connecting the back pressure pilot port of the relief main valve and the return oil passage, and a high pressure provided in the high pressure pilot oil passage A relief child valve, a low-pressure relief child valve provided in the low-pressure pilot oil passage, and a low-pressure relief valve provided in the low-pressure pilot oil passage when the overload detector detects an overwind state. An over-winding switching control valve that communicates with the pilot oil passage and the low-pressure pilot oil passage that is provided in the low-pressure pilot oil passage and communicates with the low-pressure pilot oil passage when the hook storage switching control valve is switched to the hoisting position. And click when storing switching control valve, characterized in that it comprises a.
According to a fifth aspect of the crane operating device of the present invention, in the third or fourth aspect, the hydraulic circuit includes a winch switching control valve that switches a direction of hydraulic oil supplied to the winch hydraulic actuator, and the relief circuit includes: Provided in the unloading pilot oil passage connecting the back pressure pilot port of the relief main valve and the return oil passage, and the unloading pilot oil passage, and the overwinding detector detects the overwinding state. And an unload switching control valve for communicating the unloading pilot oil passage when the winch switching control valve is switched to the hoisting position.
The crane operating device according to a sixth aspect of the present invention is the crane according to the fourth aspect, wherein the hydraulic circuit includes a winch switching control valve that switches a direction of hydraulic oil supplied to the winch hydraulic actuator, and the relief circuit includes the low-pressure pilot. A winch pilot oil passage that connects the oil passage and the return oil passage, and the winch pilot oil passage that is provided in the winch pilot oil passage and communicates with the winch pilot oil passage when the winch switching control valve is switched to the hoisting position. And a hoisting switching control valve.

According to the first, third, and fourth inventions, when the hook is in an unwinding state, the circuit pressure is set to a high pressure. Is fast and has good workability. In addition, if the hook retracting operation is performed when the hook is in an overwound state, the circuit pressure is set to a low pressure, so that the hook or the boom can be prevented from being damaged when the hook contacts the boom.
According to the second, fifth, and sixth inventions, when the hook is wound, when the hook is wound, the circuit pressure is set to the unload pressure, so that the collision between the boom and the hook is prevented. it can.

It is a hydraulic circuit of the operating device of the crane which concerns on 1st Embodiment of this invention. It is an electric circuit of the operating device of the crane. It is a hydraulic circuit of the operating device of the crane which concerns on 2nd Embodiment of this invention. It is an electric circuit of the operating device of the crane. It is a hydraulic circuit of the operating device of the crane which concerns on 3rd Embodiment of this invention. It is an electric circuit of the operating device of the crane. It is a side view of a load-type truck crane.

Next, an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
(Loading truck crane)
The crane operating device according to the first embodiment of the present invention is provided in a load-type truck crane CR. First, the configuration of the loadable truck crane CR will be described.
As shown in FIG. 7, the loading-type truck crane CR is configured by mounting a small crane 20 on a vehicle frame 13 between a cab 11 and a loading platform 12 of a general-purpose truck 10.

The small crane 20 includes a base 21 fixed on the vehicle frame 13, a post 22 provided so as to be rotatable with respect to the base 21, and a boom 23 provided on an upper end portion of the post 22 so as to be raised and lowered. Yes. The post 22 has a winch built therein. A wire rope is guided from the winch to the tip of the boom 23 and hung around the hook 24 via a pulley at the tip of the boom 23, whereby the hook 24 is connected to the tip of the boom 23. Hanging from the part. The small crane 20 includes outrigger devices 25 and 26 provided on both the left and right sides of the base 21. These crane apparatuses are operated by a hydraulic circuit described later. Lever groups 27 for operating the hydraulic circuit are provided on the left and right sides of the base 21.

(Overwind detector)
The small crane 20 is provided with an overwind detector 28 that detects the overwind state of the hook 24. The overwinding state of the hook 24 means a state in which the distance between the lower end of the boom 23 and the upper portion of the hook 24 is a predetermined length or less. The configuration of the overwind detector 28 is not particularly limited as long as the overwinding state of the hook 24 can be detected. For example, the configuration is as follows. A switch for detecting overwinding is provided at the tip of the boom 23, and a weight is suspended from the operating arm of the switch. When the hook 24 is wound up and the distance from the lower end of the boom 23 becomes a predetermined length or less, the weight is pushed up by the hook 24 and the operating arm rotates. As a result, the overwinding detection switch is switched ON / OFF, and the overwinding state of the hook 24 can be detected.

The small crane 20 having the above-described configuration can perform crane operations for unloading and unloading in a three-dimensional space by combining expansion and contraction of the boom 23, undulation, turning, and hoisting and unwinding of the hook 24. . When the hook 24 is in the overwind state, the operation of further lifting the hook 24, that is, the operations of extending the boom 23, raising the boom 23, and lifting the hook 24 are stopped, and the boom 23 and the hook 24 Is configured to prevent collisions. In the hook storing operation, the hook 24 is further wound from the overwind state, and the hook 24 is brought into contact with the boom 23 and stored. In addition to the hook storing operation, a boom storing operation for contracting and falling the boom 23 is also performed.

(Hydraulic circuit)
Next, the hydraulic circuit 30 of the small crane 20 will be described.
As shown in FIG. 1, the hydraulic circuit 30 includes a boom expansion / contraction hydraulic cylinder 31, a winch hydraulic motor 32, and a boom raising / lowering hydraulic cylinder 33 as hydraulic actuators for operating the crane device. The boom 23 is expanded and contracted by the operation of the boom extending and retracting hydraulic cylinder 31, the hook 24 is wound and unwound by the operation of the winch hydraulic motor 32, and the boom 23 is operated and lifted by the operation of the boom raising and lowering hydraulic cylinder 33.

The “winch hydraulic motor 32” corresponds to the “winch hydraulic actuator” recited in the claims. Further, the boom turning hydraulic motor for turning the boom 23 and the outrigger devices 25 and 26 are extended and retracted. The outrigger hydraulic cylinder to be operated is not shown.

In order to supply the hydraulic oil to the hydraulic actuators 31 to 33, the hydraulic circuit 30 includes a hydraulic pump 34 that discharges the hydraulic oil and a tank 35 that stores the hydraulic oil. A main oil passage 36 is connected to the discharge port of the hydraulic pump 34, and a return oil passage 37 is connected to the tank 35. The main oil passage 36 and the return oil passage 37 are connected to the hydraulic actuators 31 to 33 via switching control valves 41 to 44. In the present specification, the “main oil passage” means an oil passage that guides hydraulic oil supplied from a hydraulic source to a hydraulic actuator. The “return oil passage” means an oil passage that guides hydraulic oil discharged from the hydraulic actuator to the tank.

The switching control valves 41 to 44 are the expansion / contraction switching control valve 41, the winch switching control valve 42, the undulation switching control valve 43, and the hook storage switching control valve 44. An expansion / contraction switching control valve 41 is connected to the boom expansion / contraction hydraulic cylinder 31, a winch switching control valve 42 is connected to the winch hydraulic motor 32, and a undulation switching control valve 43 is connected to the boom raising / lowering hydraulic cylinder 33. The operation of these hydraulic actuators 31 to 33 can be switched and controlled by switching the direction of the supplied hydraulic oil. In addition to the winch switching control valve 42, a hook storage switching control valve 44 is connected to the winch hydraulic motor 32, and the direction of hydraulic oil is also switched by the hook storage switching control valve 44.

The switching control valves 41 to 44 are three-position switching control valves. The expansion / contraction switching control valve 41 has a contracted position for contracting the boom 23, a neutral position for stopping the expansion / contraction operation, and an extending position for extending. The winch switching control valve 42 has a hoisting position for winding up the hook 24, a neutral position for stopping the hoisting / lowering operation, and a lowering position for lowering. The raising / lowering switching control valve 43 has a raising position for raising the boom 23, a neutral position for stopping the raising / lowering operation, and a lying position for falling. The hook storage switching control valve 44 has a hoisting position for winding up the hook 24, a neutral position for stopping the hoisting / lowering operation, and a lowering position for lowering.

A lever is attached to each of the switching control valves 41 to 44, and the spool position can be switched by manually operating the lever. The levers attached to the switching control valves 41 to 44 are provided on the left and right sides of the base 21 as the lever group 27 (see FIG. 7). The crane device can be operated by the operator operating the lever group 27.

(Relief circuit)
The hydraulic circuit 30 is provided with a relief circuit 50 for setting the circuit pressure. Here, “circuit pressure” means the maximum hydraulic pressure in the hydraulic circuit 30. The relief circuit 50 sets the circuit pressure to one of high pressure, low pressure, and unload pressure depending on whether the hook 24 is wound or not, and the spool positions of the switching control valves 41 to 44. The greater the flow rate of the hydraulic oil, the higher the hydraulic pressure in the hydraulic circuit 30. When the hydraulic pressure becomes higher than the circuit pressure, the hydraulic oil is discharged from the relief valve. When the circuit pressure is set to a high pressure, the hydraulic actuators 31 to 33 can be operated at high speed because the discharge flow rate from the relief valve is small and the hydraulic fluid supplied to the hydraulic actuators 31 to 33 is large. When the circuit pressure is set to a low pressure, the hydraulic actuators 31 to 33 operate at a low speed because the flow rate of the hydraulic oil supplied to the hydraulic actuators 31 to 33 is small because the discharge flow rate from the relief valve is large. When the circuit pressure is set to the unload pressure, hydraulic oil is not supplied to the hydraulic actuators 31 to 33, so that the operation of the hydraulic actuators 31 to 33 can be stopped. The unload pressure is lower than the low pressure.

The relief circuit 50 is provided with a relief main valve 51. The relief main valve 51 is provided in a relief oil passage 61 that connects the main oil passage 36 and the return oil passage 37. The relief main valve 51 is provided with a back pressure chamber into which hydraulic oil that has entered from the inlet port flows, in addition to a spring that biases the spool in the closing direction. The hydraulic pressure applied to the back pressure chamber acts in the direction of closing the spool. By controlling the hydraulic pressure in the back pressure chamber with the high pressure relief valve 52 and the low pressure relief valve 53, the set pressure of the relief main valve 51 is set to one of high pressure, low pressure, and unload pressure. Then, the circuit pressure is set by the set pressure of the relief main valve 51.

The back pressure chamber of the relief main valve 51 is provided with a back pressure pilot port. The back pressure pilot port of the relief main valve 51 and the return oil passage 37 are connected by a high pressure pilot oil passage 62. A high pressure relief valve 52 is provided in the high pressure pilot oil passage 62. The back pressure pilot port of the relief main valve 51 and the return oil passage 37 are also connected by a low pressure pilot oil passage 63. A low pressure relief valve 53 is provided in the low pressure pilot oil passage 63. The low pressure pilot oil passage 63 is also provided with an overwinding switching control valve 54.

The relief circuit 50 includes an extension switching control valve 41a, a hoisting switching control valve 42a, a rising switching control valve 43a, and a hook storing switching control valve 44a. These switching control valves 41a to 44a are three-position switching control valves. The extension switching control valve 41a corresponds to the expansion / contraction switching control valve 41, and these spools are connected. Therefore, when the spool position of the expansion / contraction switching control valve 41 is switched, the spool position of the extension switching control valve 41a is also switched accordingly. Similarly, the hoisting switching control valve 42 a corresponds to the winch switching control valve 42, the raising switching control valve 43 a corresponds to the hoisting switching control valve 43, and the hook storing switching control valve 44 a corresponds to the hook storing switching control valve 44. The spools are connected to each other.

In the low-pressure pilot oil passage 63, an over-winding switching control valve 54, a hook storage switching control valve 44 a, and a low-pressure relief child valve 53 are provided from the back pressure pilot port of the relief main valve 51 toward the return oil passage 37. It is provided in order. Further, the low pressure pilot oil passage 63 has three pilot oil passages (extended pilot oil passage 64, winch pilot oil passage 65, undulating pilot oil passage) between the over-winding switching control valve 54 and the hook storage switching control valve 44a. 66). The other ends of these pilot oil passages 64 to 66 are connected to the return oil passage 37. The telescopic pilot oil passage 64 is provided with an extension switching control valve 41a, the winch pilot oil passage 65 is provided with a hoisting switching control valve 42a, and the hoisting pilot oil passage 66 is provided with an elevation switching control valve 43a. Is provided.

When the expansion / contraction switching control valve 41 is switched to the extended position, the expansion switching control valve 41a allows the expansion / contraction pilot oil passage 64 to communicate, and otherwise it blocks the expansion / contraction pilot oil passage 64. The hoisting switching control valve 42a makes the winch pilot oil passage 65 communicate when the winch switching control valve 42 is switched to the hoisting position, and shuts the winch pilot oil passage 65 in other cases. The raising / lowering switching control valve 43a communicates the hoisting pilot oil passage 66 when the hoisting switching control valve 43 is switched to the raising position, and blocks the hoisting pilot oil passage 66 in other cases. The hook storage switching control valve 44a communicates the low pressure pilot oil passage 63 when the hook storage switching control valve 44 is switched to the hoisting position, and shuts off the low pressure pilot oil passage 63 otherwise. .

The order of arrangement of the over-winding switching control valve 54, the hook storage switching control valve 44a, and the low-pressure relief child valve 53 provided in the low-pressure pilot oil passage 63 is not limited to this embodiment, and the hook storage switching control is performed. The positions of the valve 44a and the low-pressure relief child valve 53 may be reversed. In this case, the three pilot oil passages (the telescopic pilot oil passage 64, the winch pilot oil passage 65, and the undulating pilot oil passage 66) are provided between the low-pressure pilot oil passage 63 and the low-pressure relief child valve 53. Branch from between.

(electric circuit)
The over-winding switching control valve 54 is a two-position electromagnetic control valve. The electrical circuit 70 shown in FIG. 2 controls the energization of the solenoid 54s of the overwinding switching control valve 54. The electric circuit 70 is provided with a DC power supply 71, and two

conductors

72 and 73 are provided in parallel between the DC power supply 71 and the ground. One lead wire 72 is provided with a switch 28 s of the overwind detector 28. The switch 28s is opened (OFF) in the overwinding state, and is closed (ON) in the non-winding state. Relays 74 are provided on the conducting

wires

72 and 73. The relay 74 conducts the conducting wire 73 when the conducting wire 72 is energized, and interrupts the conducting wire 73 when the conducting wire 72 is out of power. The conducting wire 73 is provided with a solenoid 54s of the over-winding switching control valve 54.

When the overwinding detector 28 detects the overwinding state, the switch 28s is opened (OFF), the lead wire 72 is cut off, the lead wire 73 is cut off by the relay 74, and power is not supplied to the solenoid 54s. Then, the overwinding switching control valve 54 is switched to a position where the low pressure pilot oil passage 63 is communicated (see FIG. 1).

On the other hand, when the overwinding detector 28 does not detect the overwinding state (in the non-overwinding state), the switch 28s is closed (ON), the conducting wire 72 is energized, and the conducting wire 73 is energized by the relay 74. The electric power is supplied to the solenoid 54s. Then, the over-winding switching control valve 54 is switched to a position where the low pressure pilot oil passage 63 is shut off (see FIG. 1).

In summary, the over-winding switching control valve 54 communicates with the low-pressure pilot oil passage 63 when in the over-winding state and shuts off the low-pressure pilot oil passage 63 when in the non-over-winding state.

(Operation device operation)
Next, the operation of the operating device according to the present embodiment will be described.
(1) When the hook 24 is in an unwinding state (when the winding detector 28 has not detected the winding state), the over-winding switching control valve 54 blocks the low-pressure pilot oil passage 63. Then, the back pressure pilot port of the relief main valve 51 is disconnected from the low pressure relief child valve 53 and only the high pressure relief child valve 52 is connected. Therefore, the set pressure of the relief main valve 51 is set to a high pressure. That is, the circuit pressure is set to a high pressure.

In this case, the circuit pressure remains high regardless of the position of the switching control valves 41 to 44 in any combination. Since the pressure of the hydraulic oil supplied to the hydraulic actuators 31 to 33 is high, the outputs of the hydraulic actuators 31 to 33 are high, and the hydraulic actuators 31 to 33 can be operated even when the load is large. Further, since the flow rate of the hydraulic oil supplied to the hydraulic actuators 31 to 33 is large, the hydraulic actuators 31 to 33 can be operated at high speed. Therefore, the crane work can be performed comfortably, and the hook storage work can be comfortably performed.

As described above, in the hook storage operation, the hook 24 is wound up by operating the hook storage switching control valve 44 even in the non-winding state. In addition to the hook storing operation, a boom storing operation for contracting and falling the boom 23 is also performed. As described above, when the hook 24 is in the non-winding state, the circuit pressure is set to a high value, and the flow rate of the hydraulic oil supplied to the hydraulic actuators 31 to 33 is increased. Even if the control valve 44 is operated, the hydraulic actuators 31 to 33 operate quickly and workability is good until the winding state is reached. For example, even if the hook storage switching control valve 44 is operated to wind the hook 24 and the boom 23 is contracted and laid down, the hydraulic actuators 31 to 33 operate quickly, so that the workability is good. The storing operation can be performed comfortably.

(2) When the hook 24 is in the overwinding state (when the overwinding detector 28 detects the overwinding state), the overwinding switching control valve 54 causes the low pressure pilot oil passage 63 to communicate. In this case, when the hook storage switching control valve 44 is switched to the hoisting position, the hook storage switching control valve 44a is switched in conjunction therewith, and the low pressure pilot oil passage 63 is communicated. Then, the back pressure pilot port of the relief main valve 51 is connected to the low pressure relief child valve 53. Therefore, the set pressure of the relief main valve 51 is set to a low pressure. That is, the circuit pressure is set to a low pressure.

In the hook storing work, it is necessary to further wind up the hook 24 from the overwind state. By switching the hook storage switching control valve 44 to the hoisting position, the hook 24 can be wound up and stored even in the overwind state. Here, when the hook retracting operation is performed when the hook 24 is in an overwound state, the circuit pressure is set to a low pressure. Therefore, when the hook 24 comes into contact with the boom 23, the hook 24 and the boom 23 are damaged. Can be prevented.

(3) When the hook 24 is in the overwinding state (when the overwinding detector 28 detects the overwinding state), the overwinding switching control valve 54 causes the low pressure pilot oil passage 63 to communicate. In this case, when at least one of the expansion / contraction switching control valve 41, the winch switching control valve 42, and the undulation switching control valve 43 is switched to the hook hoisting operation side, the circuit pressure is set to the unload pressure. Here, the “hook hoisting operation side” means an extended position in the expansion / contraction switching control valve 41, a hoisting position in the winch switching control valve 42, and an ascending position in the undulation switching control valve 43.

When at least one of the expansion / contraction switching control valve 41, the winch switching control valve 42, and the undulation switching control valve 43 is switched to the hook hoisting operation side, the switching control valves 41a to 43a are switched in conjunction therewith, and the expansion pilot At least one of the oil passage 64, the winch pilot oil passage 65, and the undulating pilot oil passage 66 communicates. Then, the back pressure pilot port of the relief main valve 51 is connected to the return oil passage 37, and the hydraulic pressure in the back pressure chamber of the relief main valve 51 becomes zero. Therefore, the set pressure of the relief main valve 51 is set to the unload pressure. That is, the circuit pressure is set to the unload pressure.

Therefore, when the operation of any one of the extension of the boom 23, the raising of the boom 23, and the lifting of the hook 24 is performed when the hook 24 is in an overwound state, the circuit pressure is set to the unload pressure. Each operation | movement is stopped and the collision with the boom 23 and the hook 24 can be prevented.

[Second Embodiment]
Next, a crane operating device according to a second embodiment of the present invention will be described. The operating device of the present embodiment is different from the first embodiment in the relief circuit 50 and the electric circuit 70 of the hydraulic circuit 30. Since the rest of the configuration is the same as that of the first embodiment, the same reference numerals are assigned to the same members, and descriptions thereof are omitted.

(Relief circuit)
As shown in FIG. 3, the relief circuit 50 of this embodiment is provided with a relief main valve 51. The relief main valve 51 is provided in a relief oil passage 61 that connects the main oil passage 36 and the return oil passage 37. The back pressure pilot port of the relief main valve 51 and the return oil passage 37 are connected by a high pressure pilot oil passage 62. A high pressure relief valve 52 is provided in the high pressure pilot oil passage 62. The back pressure pilot port of the relief main valve 51 and the return oil passage 37 are also connected by a low pressure pilot oil passage 63. The low pressure pilot oil passage 63 is provided with a low pressure relief valve 53, an overwinding switching control valve 54, and a hook retracting switching control valve 44a. Further, the back pressure pilot port of the relief main valve 51 and the return oil passage 37 are also connected by an unloading pilot oil passage 69. An unload switching control valve 59 is provided in the unload pilot oil passage 69.

The hook storage switching control valve 44a corresponds to the hook storage switching control valve 44, and these spools are connected. Therefore, when the spool position of the hook storage switching control valve 44 is switched, the spool position of the hook storage switching control valve 44a is also switched accordingly. The hook storage switching control valve 44a communicates the low pressure pilot oil passage 63 when the hook storage switching control valve 44 is switched to the hoisting position, and shuts off the low pressure pilot oil passage 63 otherwise. .

The expansion / contraction switching control valve 41, the winch switching control valve 42, and the undulation switching control valve 43 are provided with an extension detection switch 41s, a hoisting detection switch 42s, and an elevation detection switch 43s, respectively. The extension detection switch 41s is opened (OFF) when the expansion / contraction switching control valve 41 is switched to the extended position, and is closed (ON) in other cases. The hoisting detection switch 42s is opened (OFF) when the winch switching control valve 42 is switched to the hoisting position, and is closed (ON) in other cases. The raising / lowering detection switch 43s is opened (OFF) when the raising / lowering switching control valve 43 is switched to the raising / lowering position, and is otherwise closed (ON).

The arrangement order of the over-winding switching control valve 54, the low-pressure relief child valve 53, and the hook storage switching control valve 44a provided in the low-pressure pilot oil passage 63 is not limited to this embodiment, and any arrangement order may be adopted. Good.

(electric circuit)
The over-winding switching control valve 54 and the unloading switching control valve 59 are two-position electromagnetic control valves. The electric circuit 70 shown in FIG. 4 controls energization of the solenoid 54s of the over-winding switching control valve 54 and the solenoid 59s of the unloading switching control valve 59. The electric circuit 70 is provided with a DC power supply 71, and four conducting wires 75 to 78 are provided in parallel between the DC power supply 71 and the ground. Two conducting

wires

76a and 76b connected in parallel are interposed in the middle portion of the conducting wire 76. The conducting wire 77 branches into a conducting wire 77a and a conducting wire 77b on the way.

The lead wire 76 is provided with a switch 28 s of the overwind detector 28. The switch 28s is opened (OFF) in the overwinding state, and is closed (ON) in the non-winding state. The lead wire 77a is provided with an extension detection switch 41s, a hoisting detection switch 42s, and an elevation detection switch 43s.

A relay 79 is provided on the conducting

wires

76b and 75. The relay 79 conducts the conducting wire 75 when the conducting wire 76b is energized, and interrupts the conducting wire 75 when the conducting wire 76b is out of power. A relay 80 is provided on the conducting

wires

76a and 77b. The relay 80 conducts the conductor 77b when the conductor 76a is energized, and interrupts the conductor 77b when the conductor 76a is out of power. A relay 81 is provided on the conducting

wires

77 and 78. The relay 81 conducts the conducting wire 78 when the conducting wire 77 is energized, and interrupts the conducting wire 78 when the conducting wire 77 is out of power.

The conducting wire 75 is provided with a solenoid 54 s of the over-winding switching control valve 54. The conducting wire 78 is provided with a solenoid 59s of the unload switching control valve 59.

When the overwinding detector 28 detects the overwinding state, the switch 28s is opened (OFF), the lead wire 76b is cut off, the lead wire 75 is cut off by the relay 79, and power is not supplied to the solenoid 54s. Then, the over-winding switching control valve 54 is switched to a position where the low pressure pilot oil passage 63 is communicated (see FIG. 3).

On the other hand, when the overwinding detector 28 does not detect the overwinding state (in a non-overwinding state), the switch 28s is closed (ON), the conducting wire 76b is energized, and the conducting wire 75 is energized by the relay 79. The electric power is supplied to the solenoid 54s. Then, the over-winding switching control valve 54 is switched to a position where the low pressure pilot oil passage 63 is shut off (see FIG. 3).

Further, when the overwind detector 28 detects the overwind state, the switch 28s is opened (OFF), the lead wire 76a is cut off, and the lead wire 77b is cut off by the relay 80. In this case, when at least one of the extension detection switch 41s, the hoisting detection switch 42s, and the raising detection switch 43s is opened (OFF), the conducting wire 77 is cut off, the conducting wire 78 is cut off by the relay 81, and the solenoid 59s. Is not supplied with power. Then, the unload switching control valve 59 is switched to a position where the unloading pilot oil passage 69 is communicated (see FIG. 3).

In other cases, power is supplied to the solenoid 59s. Then, the unload switching control valve 59 is switched to a position where the unloading pilot oil passage 69 is shut off (see FIG. 3).

In summary, the unloading switching control valve 59 is in an overwind state, and at least one of the expansion / contraction switching control valve 41, the winch switching control valve 42, and the undulation switching control valve 43 is operated to perform hook hoisting. The unloading pilot oil passage 69 is communicated when switched to the side, and the unloading pilot oil passage 69 is blocked in other cases.

(Operation device operation)
Next, the operation of the operating device according to the present embodiment will be described.
(1) When the hook 24 is in an unwinding state (when the winding detector 28 has not detected the winding state), the over-winding switching control valve 54 blocks the low-pressure pilot oil passage 63. Further, the unload switching control valve 59 blocks the unload pilot oil passage 69. Then, only the high-pressure relief child valve 52 is connected to the back pressure pilot port of the relief main valve 51. Therefore, the set pressure of the relief main valve 51 is set to a high pressure. That is, the circuit pressure is set to a high pressure.

In this case, the circuit pressure remains high regardless of the position of the switching control valves 41 to 44 in any combination. Since the flow rate of the hydraulic oil supplied to the hydraulic actuators 31 to 33 is large, the hydraulic actuators 31 to 33 can be operated at high speed. Therefore, the crane work can be performed comfortably. Further, during the hook storage operation, that is, even when the hook storage switching control valve 44 is operated, the hydraulic actuators 31 to 33 operate fast and workability is good until the winding is over. For example, even if the hook storage switching control valve 44 is operated to wind the hook 24, and the boom 23 is contracted and laid down, the hydraulic actuators 31 to 33 operate quickly, so the workability is good.

As described above, when the hook retracting operation is performed when the hook 24 is in an overwound state, the circuit pressure is set to a low pressure. Therefore, when the hook 24 comes into contact with the boom 23, the hook 24 or the boom 23 is damaged. Can be prevented.

(3) When the hook 24 is in the overwind state (when the overwind detector 28 detects the overwind state), the expansion / contraction switching control valve 41, the winch switching control valve 42, and the undulation switching control valve 43 When at least one of them is switched to the hook hoisting operation side, the unload switching control valve 59 causes the unloading pilot oil passage 69 to communicate. Then, the back pressure pilot port of the relief main valve 51 is connected to the return oil passage 37, and the hydraulic pressure in the back pressure chamber of the relief main valve 51 becomes zero. Therefore, the set pressure of the relief main valve 51 is set to the unload pressure. That is, the circuit pressure is set to the unload pressure.

[Third Embodiment]
Next, a crane operating device according to a third embodiment of the present invention will be described. The operating device of the present embodiment is different from the second embodiment in the relief circuit 50 and the electric circuit 70 of the hydraulic circuit 30. Since the rest of the configuration is the same as that of the second embodiment, the same reference numerals are assigned to the same members, and descriptions thereof are omitted.

(Relief circuit)
As shown in FIG. 5, the relief circuit 50 of the present embodiment is provided with a relief main valve 51. The relief main valve 51 is provided in a relief oil passage 61 that connects the main oil passage 36 and the return oil passage 37. The back pressure pilot port of the relief main valve 51 and the return oil passage 37 are connected by a high pressure pilot oil passage 62. A high pressure relief valve 52 is provided in the high pressure pilot oil passage 62. The back pressure pilot port of the relief main valve 51 and the return oil passage 37 are also connected by a low pressure pilot oil passage 63. The low pressure pilot oil passage 63 is provided with a low pressure relief valve 53 and a low pressure switching control valve 55. Further, the back pressure pilot port of the relief main valve 51 and the return oil passage 37 are also connected by an unloading pilot oil passage 69. An unload switching control valve 59 is provided in the unload pilot oil passage 69.

The expansion / contraction switching control valve 41, the winch switching control valve 42, the undulation switching control valve 43, and the hook storage switching control valve 44 include an extension detection switch 41s, a hoisting detection switch 42s, an elevation detection switch 43s, and a hook storage detection, respectively. A switch 44s is provided. The extension detection switch 41s is opened (OFF) when the expansion / contraction switching control valve 41 is switched to the extended position, and is closed (ON) in other cases. The hoisting detection switch 42s is opened (OFF) when the winch switching control valve 42 is switched to the hoisting position, and is closed (ON) in other cases. The raising / lowering detection switch 43s is opened (OFF) when the raising / lowering switching control valve 43 is switched to the raising / lowering position, and is otherwise closed (ON). The hook storage detection switch 44s is opened (OFF) when the hook storage switching control valve 44 is switched to the hoisting position, and is closed (ON) in other cases.

The order of arrangement of the low pressure switching control valve 55 and the low pressure relief child valve 53 provided in the low pressure pilot oil passage 63 is not particularly limited.

(electric circuit)
The low-pressure switching control valve 55 and the unloading switching control valve 59 are two-position electromagnetic control valves. The electric circuit 70 shown in FIG. 6 controls energization of the solenoid 55s of the low pressure switching control valve 55 and the solenoid 59s of the unloading switching control valve 59. The electric circuit 70 is provided with a DC power supply 71, and four conducting wires 75 to 78 are provided in parallel between the DC power supply 71 and the ground. Two

conductive wires

75a and 75b connected in parallel are interposed in an intermediate portion of the conductive wire 75. Two conducting

wires

The lead wire 76 is provided with a switch 28 s of the overwind detector 28. The switch 28s is opened (OFF) in the overwinding state, and is closed (ON) in the non-winding state. The lead wire 77a is provided with an extension detection switch 41s, a hoisting detection switch 42s, and an elevation detection switch 43s. The lead wire 75b is provided with a hook storage detection switch 44s.

Relays 79 are provided on the conducting

wires

76b and 75a. The relay 79 conducts the conducting wire 75a when the conducting wire 76b is energized, and interrupts the conducting wire 75a when the conducting wire 76b is out of power. A relay 80 is provided on the conducting

wires

The conducting wire 75 is provided with a solenoid 55s of the low-pressure switching control valve 55. The conducting wire 78 is provided with a solenoid 59s of the unload switching control valve 59.

When the overwinding detector 28 detects the overwinding state, the switch 28s is opened (OFF), the lead wire 76b is cut off, and the lead wire 75a is cut off by the relay 79. In this case, when the hook retract detection switch 44s is opened (OFF), power is not supplied to the solenoid 55s. Then, the low pressure switching control valve 55 is switched to a position where the low pressure pilot oil passage 63 is communicated (see FIG. 5). If the hook retract detection switch 44s is closed (ON), power is supplied to the solenoid 55s through the conductor 75b. Then, the low pressure switching control valve 55 is switched to a position where the low pressure pilot oil passage 63 is shut off (see FIG. 5).

On the other hand, when the overwinding detector 28 does not detect the overwinding state (in the non-overwinding state), the switch 28s is closed (ON), the conducting wire 76b is energized, and the conducting wire 75a is energized by the relay 79. Then, electric power is supplied to the solenoid 55s. Then, the low pressure switching control valve 55 is switched to a position where the low pressure pilot oil passage 63 is shut off (see FIG. 5).

In summary, when the low pressure switching control valve 55 is in the over-winding state and the hook storage switching control valve 44 is switched to the hoisting position, the low pressure pilot oil passage 63 is communicated. In this case, the low pressure pilot oil passage 63 is shut off.

Further, when the overwind detector 28 detects the overwind state, the switch 28s is opened (OFF), the lead wire 76a is cut off, and the lead wire 77b is cut off by the relay 80. In this case, when at least one of the extension detection switch 41s, the hoisting detection switch 42s, and the raising detection switch 43s is opened (OFF), the conducting wire 77 is cut off, the conducting wire 78 is cut off by the relay 81, and the solenoid 59s. Is not supplied with power. Then, the unload switching control valve 59 is switched to a position where the unloading pilot oil passage 69 is communicated (see FIG. 5).

In other cases, power is supplied to the solenoid 59s. Then, the unload switching control valve 59 is switched to a position where the unloading pilot oil passage 69 is shut off (see FIG. 5).

(Operation device operation)
Next, the operation of the operating device according to the present embodiment will be described.
(1) When the hook 24 is in a non-winding state (when the winding detector 28 has not detected the winding state), the low-pressure switching control valve 55 blocks the low-pressure pilot oil passage 63. Further, the unload switching control valve 59 blocks the unload pilot oil passage 69. Then, only the high-pressure relief child valve 52 is connected to the back pressure pilot port of the relief main valve 51. Therefore, the set pressure of the relief main valve 51 is set to a high pressure. That is, the circuit pressure is set to a high pressure.

(2) When the hook 24 is in the overwinding state (when the overwinding detector 28 detects the overwinding state) and the hook storage switching control valve 44 is switched to the hoisting position, the low pressure switching control is performed. The valve 55 makes the low pressure pilot oil passage 63 communicate. Then, the back pressure pilot port of the relief main valve 51 is connected to the low pressure relief child valve 53. Therefore, the set pressure of the relief main valve 51 is set to a low pressure. That is, the circuit pressure is set to a low pressure.

[Other Embodiments]
Although the said embodiment demonstrated the load-type truck crane CR to the example, the operating device of the crane which concerns on this invention may be provided in another kind of crane.

In the above embodiment, when the operation of extending the boom 23, raising the boom 23, or hoisting the hook 24 is performed when the hook 24 is in an overwound state, the circuit pressure is set to the unload pressure. It is configured. However, depending on the construction of the crane, the hook 24 may not be wound up even if the boom 23 is extended or raised. In this case, the circuit pressure may not be set to the unload pressure even if the boom 23 is extended or raised when the hook 24 is in the overwind state.

DESCRIPTION OF SYMBOLS 10 General purpose truck 20 Small crane 23 Boom 24 Hook 28 Overwind detector 30 Hydraulic circuit 31 Boom expansion-contraction hydraulic cylinder 32 Winch hydraulic motor 33 Boom raising / lowering hydraulic cylinder 41 Expansion / contraction switching control valve 41a Extension switching control valve 42 Winch switching control Valve 42a Hoisting switching control valve 43 Elevation switching control valve 43a Lifting switching control valve 44 Hook retract switching control valve 44a Hook retracting switching control valve 50 Relief circuit 51 Relief main valve 52 High pressure relief child valve 53 Low pressure relief child valve 54 Overwinding switching control valve 70 Electric circuit

Claims

A crane operating device comprising a boom and a hook suspended from the boom,
An overwind detector for detecting the overwind state of the hook; and
A hydraulic circuit for operating the crane,
The hydraulic circuit is
A winch hydraulic actuator for operating the hook to wind up and down;
A hook storage switching control valve for switching the direction of hydraulic oil supplied to the winch hydraulic actuator;
A relief circuit for setting the circuit pressure,
The relief circuit is
When the overwind detector does not detect the overwind state, set the circuit pressure to a high pressure,
Crane operation characterized in that the circuit pressure is set to a low pressure when the overwind detector detects an overwind state and the hook storage switching control valve is switched to the hoisting position. apparatus.
The hydraulic circuit is
A winch switching control valve for switching the direction of hydraulic oil supplied to the winch hydraulic actuator;
The relief circuit is
The circuit pressure is set to an unload pressure when the overwinding detector detects an overwinding state and the winch switching control valve is switched to a hoisting position. The crane operating device according to claim 1.
The relief circuit is
A relief main valve provided between the main oil passage and the return oil passage;
A high pressure pilot oil passage connecting the back pressure pilot port of the relief main valve and the return oil passage;
A low pressure pilot oil passage connecting the back pressure pilot port of the relief main valve and the return oil passage;
A high-pressure relief valve provided in the high-pressure pilot oil passage;
A low-pressure relief valve provided in the low-pressure pilot oil passage;
The low pressure pilot oil provided in the low pressure pilot oil passage, when the overwind detector detects an overwind state and the hook storage switching control valve is switched to the hoisting position. The crane operating device according to claim 1, further comprising a low-pressure switching control valve for communicating the road.
The relief circuit is
A relief main valve provided between the main oil passage and the return oil passage;
A high pressure pilot oil passage connecting the back pressure pilot port of the relief main valve and the return oil passage;
A low pressure pilot oil passage connecting the back pressure pilot port of the relief main valve and the return oil passage;
A high-pressure relief valve provided in the high-pressure pilot oil passage;
A low-pressure relief valve provided in the low-pressure pilot oil passage;
An overwinding switching control valve that is provided in the low pressure pilot oil passage, and that communicates the low pressure pilot oil passage when the overwind detector detects an overwind state;
A hook storage switching control valve that is provided in the low pressure pilot oil passage and that connects the low pressure pilot oil passage when the hook storage switching control valve is switched to the hoisting position. The crane operating device according to claim 1.
The hydraulic circuit is
A winch switching control valve for switching the direction of hydraulic oil supplied to the winch hydraulic actuator;
The relief circuit is
An unloading pilot oil passage connecting the back pressure pilot port of the relief main valve and the return oil passage;
The unloading pilot oil passage provided in the unloading pilot oil passage, when the overwinding detector detects an overwinding state and the winch switching control valve is switched to the hoisting position. The crane operating device according to claim 3 or 4, further comprising an unloading switching control valve for communicating the oil passage.
The hydraulic circuit is
A winch switching control valve for switching the direction of hydraulic oil supplied to the winch hydraulic actuator;
The relief circuit is
A winch pilot oil passage connecting the low pressure pilot oil passage and the return oil passage;
A hoisting pilot oil passage, and when the winch switching control valve is switched to the hoisting position, the hoisting pilot oil passage communicates with the hoisting pilot control passage. 4. The crane operating device according to 4.