Hydraulic equipment control device

Abstract

To provide a hydraulic equipment control device that can suppress occurrence of behavior of components different from what are intended by an operator.SOLUTION: A hydraulic equipment control device includes a hydraulic control unit that controls the pressure oil supplied to the hoisting boom hoist hydraulic cylinder, which displaces the hoisting boom by extending or retracting. When an automatic pressurization condition, which is a condition for automatically changing a supply destination of pressure oil, is met while no operation is being performed by the operator during a work mode in which pressure oil is supplied to a folding boom extension / retraction hydraulic cylinder and a folding boom hoist hydraulic cylinder in response to operation of a folding boom by the operator, the hydraulic control unit transitions to an automatic pressurization mode in which pressure oil is automatically supplied only to the hoisting boom hoist hydraulic cylinder to restore the internal pressure of the hoisting boom hoist hydraulic cylinder, which has decreased over time.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a technique for controlling the operation of a component such as a luffing boom included in a crane device.

Background Art

[0002] As a component that operates by hydraulic pressure, for example, there is a crane device included in a tower crane or the like. As a crane device, for example, as disclosed in Patent Document 1, on the base of the crane, there is a luffing boom that is supported so as to be able to luff around a horizontal first axis, and at the tip of the luffing boom, there is a folding boom that is supported so as to be able to luff around a horizontal second axis.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional component such as the crane device disclosed in Patent Document 1, when operating for a long time, the internal pressure of a hydraulic cylinder (for example, a luffing boom hydraulic cylinder for luffing the luffing boom) gradually decreases. For this reason, for example, when the luffing boom is luffed to a certain angle (an angle for performing an operation of handling a suspended load, etc.) and the suspended load is moved up and down, the internal pressure of the hydraulic cylinder decreases, resulting in a pressure drop and an unstable standing state of the luffing boom, and there is a possibility that a behavior different from the operator's intention may occur in the component.

[0005] In view of the above problems, an object of the present invention is to provide a hydraulic equipment control device capable of suppressing the occurrence of a behavior different from the operator's intention in a component.

Means for Solving the Problems

[0006] The hydraulic equipment control device according to one aspect of the present invention controls the operation of a tilting boom that is attached to the base of a work machine so as to be tiltable, and the operation of a bending boom that is attached to the tip of the tilting boom so as to be tiltable and whose posture changes due to the posture change of the tilting boom. The hydraulic equipment control device includes a hydraulic control unit. The tilting boom is displaced by the extension or contraction of a first hydraulic cylinder to change the posture of the bending boom. The bending boom is displaced by the extension or contraction of a second hydraulic cylinder that is a hydraulic cylinder different from the first hydraulic cylinder and whose pressure oil supply source is the same as that of the first hydraulic cylinder. The hydraulic control unit controls the pressure oil supplied to the first hydraulic cylinder and the second hydraulic cylinder. Further, the first hydraulic cylinder is a cylinder whose internal pressure decreases over time. And when the automatic pressurization condition, which is a condition that is established when no operation is being performed by the operator during the execution of the work mode in which pressure oil is supplied to the second hydraulic cylinder in response to the operation of the bending boom by the operator and that automatically changes the supply destination of the pressure oil, is established, the hydraulic control unit automatically supplies pressure oil only to the first hydraulic cylinder so as to restore the internal pressure of the first hydraulic cylinder that has decreased over time, and shifts to the automatic pressurization mode.

Effects of the Invention

[0007] According to the hydraulic equipment control device of the present invention, even when the internal pressure of the first hydraulic cylinder has decreased, when the automatic pressurization condition is satisfied, pressure oil is supplied to the first hydraulic cylinder in the same direction as when the first hydraulic cylinder is extended. For this reason, even when the internal pressure of the first hydraulic cylinder has decreased, by supplying pressure oil to the first hydraulic cylinder in the same direction as when the first hydraulic cylinder is extended, the internal pressure of the first hydraulic cylinder is restored. As a result, it is possible to suppress the occurrence of behavior different from the operator's intention in the tilting boom.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0009] Hereinafter, a tower crane, which is an embodiment of a work vehicle equipped with a hydraulic equipment control device according to the present invention, will be described with appropriate reference to the drawings. Note that the drawings are schematic. Therefore, it should be noted that the relationship between the thickness and the planar dimensions, the ratio, etc. may be different from the actual ones, and there may be parts where the dimensional relationship and ratio are different between the drawings. Further, the following embodiments illustrate devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the material, shape, structure, arrangement, etc. of the components in the following embodiments.

[0010] (Embodiment) (Configuration) As shown in FIGS. 1 to 3, the tower crane 1 (working machine) includes a chassis frame 2, a traveling device 3, a base 4, a column 5, a crane device 6, and an outrigger device 9. In addition to this, the tower crane 1 includes a driver's seat 10, an operation unit 11, a winch 12, a wire rope 13, a hook 14, a prime mover 15, a control box 16, and a hook storage bracket 17.

[0011] Furthermore, as shown in FIG. 4, the tower crane 1 includes, as hydraulic actuators, a slewing hydraulic motor 30, a boom hoisting and telescoping hydraulic cylinder 31, a folding boom telescoping hydraulic cylinder 32, and a winch hydraulic motor 33. In addition to this, as shown in FIGS. 1 and 4, the tower crane 1 includes, as hydraulic actuators, a boom hoisting hydraulic cylinder 34, a folding boom hoisting hydraulic cylinder 35, and a traveling motor 38. In FIGS. 1 to 3, the direction in which the tower crane 1 moves forward is indicated as "front" in the vehicle longitudinal direction, and the direction in which the tower crane 1 moves backward is indicated as "rear" in the vehicle longitudinal direction. Also, in FIG. 3, with the state in which the tower crane 1 moves forward as a reference, the right side of the tower crane 1 is indicated as "right side" in the vehicle width direction, and the left side of the tower crane 1 is indicated as "left side" in the vehicle width direction. Therefore, FIGS. 1 and 2 are right side views of the tower crane 1.

[0012] The traveling device 3 is provided at the lower part of the chassis frame 2. Also, the traveling device 3 is, for example, a crawler type traveling device with rubber crawlers mounted on the left and right. The base 4 is connected to the upper part of the chassis frame 2. The column 5 is rotatably attached to the upper part of the base 4. The crane device 6 includes a hoisting boom 7 and a folding boom 8. The hoisting boom 7 is a telescopic boom and is attached to the upper end of the column 5 so as to be able to be hoisted. Also, the hoisting boom 7 is composed of a nested box-type boom. The folding boom 8 is a telescopic boom and is attached to the tip of the hoisting boom 7 so as to be able to be hoisted.

[0013] Also, as shown in FIG. 3, a winch 12 is arranged on the rear end face of the hoisting boom 7. The wire rope 13 wound around the winch 12 is guided to the tip of the folding boom 8 via the first sheave 44 and the second sheave 45, and is attached to the hook 14 via the third sheave 46 and a fourth sheave (not shown). As a result, the hook 14 is suspended from the tip of the folding boom 8. The third sheave 46 is disposed above the folding boom 8 at the tip of the folding boom 8. The fourth sheave is disposed inside the folding boom 8 below the third sheave 46.

[0014] The outrigger device 9 includes a right front outrigger 9RF, a right rear outrigger 9RR, a left front outrigger 9LF, and a left rear outrigger 9LR. The right front outrigger 9RF, the right rear outrigger 9RR, the left front outrigger 9LF, and the left rear outrigger 9LR each include a base end side arm and a tip end side arm. The base end side arm is provided on the upper part of the chassis frame 2 so as to be rotatable and vertically movable. The tip end side arm is a telescopic arm and is provided so as to be vertically movable with respect to the tip of the base end side arm.

[0015] The right front outrigger 9RF is disposed on the upper part of the chassis frame 2 on the right side in the vehicle width direction and in the front in the vehicle longitudinal direction. The right front outrigger 9RF includes a right front transverse outrigger cylinder 36RF and a right front longitudinal outrigger cylinder 37RF (see FIG. 4). The right front transverse outrigger cylinder 36RF is a hydraulic actuator that causes the tip end side arm to perform a lifting and telescoping operation. The right front longitudinal outrigger cylinder 37RF is a hydraulic actuator that causes the base end side arm to perform a lifting operation.

[0016] The right rear outrigger 9RR is disposed on the upper part of the chassis frame 2 on the right side in the vehicle width direction and in the rear in the vehicle longitudinal direction. The right rear outrigger 9RR includes a right rear transverse outrigger cylinder 36RR and a right rear longitudinal outrigger cylinder 37RR (see FIG. 4). The right rear horizontal outrigger cylinder 36RR is a hydraulic actuator that causes the tip-side arm to perform a pitching motion and a telescoping motion. The right rear vertical outrigger cylinder 37RR is a hydraulic actuator that causes the base-side arm to perform a pitching motion.

[0017] The left front outrigger 9LF is disposed above the chassis frame 2 on the left side in the vehicle width direction and in the front in the vehicle longitudinal direction. The left front outrigger 9LF includes a left front horizontal outrigger cylinder 36LF and a left front vertical outrigger cylinder 37LF (see FIG. 4). The left front horizontal outrigger cylinder 36LF is a hydraulic actuator that causes the tip-side arm to perform a pitching motion and a telescoping motion. The left front vertical outrigger cylinder 37LF is a hydraulic actuator that causes the base-side arm to perform a pitching motion.

[0018] The left rear outrigger 9LR is disposed above the chassis frame 2 on the left side in the vehicle width direction and in the rear in the vehicle longitudinal direction. The left rear outrigger 9LR includes a left rear horizontal outrigger cylinder 36LR and a left rear vertical outrigger cylinder 37LR (see FIG. 4). The left rear horizontal outrigger cylinder 36LR is a hydraulic actuator that causes the tip-side arm to perform a pitching motion and a telescoping motion. The left rear vertical outrigger cylinder 37LR is a hydraulic actuator that causes the base-side arm to perform a pitching motion.

[0019] In the following description, the right front outrigger 9RF, the right rear outrigger 9RR, the left front outrigger 9LF, and the left rear outrigger 9LR may be referred to as "each outrigger 9RF to 9LR". Also, in the following description, the right front horizontal outrigger cylinder 36RF, the right rear horizontal outrigger cylinder 36RR, the left front horizontal outrigger cylinder 36LF, and the left rear horizontal outrigger cylinder 36LR may be referred to as "each horizontal outrigger cylinder 36RF to 36LR". Similarly, in the following description, the right front vertical outrigger cylinder 37RF, the right rear vertical outrigger cylinder 37RR the left front vertical outrigger cylinder 37LF, and the left rear vertical outrigger cylinder 37LR may be referred to as "each vertical outrigger cylinder 37RF to 37LR".

[0020] The outrigger device 9 is configured to be movable from the stored state shown in FIG. 1 to a radially protruding position with respect to the aircraft body by manually rotating each of the outriggers 9RF to 9LR in the horizontal direction, as shown in FIGS. 2 and 3. FIGS. 2 and 3 show a state in which the outrigger device 9 is deployed and the elevating boom 7 and the folding boom 8 are erected. After moving each of the outriggers 9RF to 9LR to the protruding position, each of the lateral outrigger cylinders 36RF to 36LR is driven by operating the operation unit 11 or by operating a remote operation device described later. By driving each of the lateral outrigger cylinders 36RF to 36LR, the tip-side arms of each of the outriggers 9RF to 9LR can be moved and extended in the upward direction. Further, after moving each of the outriggers 9RF to 9LR to the protruding position, each of the vertical outrigger cylinders 37RF to 37LR is driven to move the base-side arms of each of the outriggers 9RF to 9LR in the downward direction and to ground the lower part of the tip-side arms on the ground. This ensures the same lifting performance for the entire circumference of the aircraft body and improves the stability of the aircraft body.

[0021] The driver's seat 10 is where the operator (driver) sits during operations such as when the tower crane 1 is traveling. The driver's seat 10 is provided so as to protrude from the rear of the chassis frame 2 via a link mechanism. The operation unit 11 is provided at the rear end of the chassis frame 2. The operation unit 11 includes a pair of left and right travel operation levers 11a, an operation panel (not shown), and a plurality of control valve operation levers (not shown). The travel operation lever 11a is disposed in front of the driver's seat 10. A plurality of operation switches are arranged on the operation panel. The plurality of operation switches include an operation target changeover switch, an elevating boom changeover switch, a telescopic boom changeover switch, a hook fixing switch, an outrigger selection switch, an outrigger operation switch, and the like.

[0022] The operation target switching switch is a switch for switching between the crane mode and the outrigger mode. The crane mode is a mode for enabling the operation of the crane device 6. The outrigger mode is a mode for enabling the operation of the outrigger device 9. The boom hoisting switching switch is a switch for switching between the boom hoisting operation mode and the folding boom hoisting operation mode in the crane mode switched by the operation target switching switch. The boom hoisting operation mode is a mode for enabling the hoisting operation of the boom 7. The folding boom hoisting operation mode is a mode for enabling the hoisting operation of the folding boom 8. The telescopic boom switching switch is a switch for switching between the boom telescopic operation mode and the folding boom telescopic operation mode in the crane mode switched by the operation target switching switch. The boom telescopic operation mode is a mode for enabling the telescopic operation of the boom 7. The folding boom telescopic operation mode is a mode for enabling the telescopic operation of the folding boom 8.

[0023] It is impossible to simultaneously operate the traveling device 3, the crane device 6, and the outrigger device 9, and the boom 7 and the folding boom 8 in the crane mode, by the operation target switching switch, the boom hoisting switching switch, and the telescopic boom switching switch. The outrigger selection switch is a switch for selecting the outrigger to be operated from each of the outriggers 9RF to 9LR. The outrigger operation switch is a switch for operating the outrigger selected by the outrigger selection switch.

[0024] The plurality of control valve operation levers are provided on the right side of the operation panel. Also, the plurality of control valve operation levers operate the spools respectively possessed by the outrigger switching control valve 82, the slewing switching control valve 83, the boom telescopic switching control valve 84, the winch switching control valve 85, and the boom hoisting switching control valve 86. In addition, each control valve operation lever is provided corresponding to various hydraulic actuators, and by tilting it from the neutral position in the direction of approaching or separating from the aircraft body, it is possible to drive the hydraulic actuator corresponding to the control valve operation lever. Specifically, each control valve operation lever includes a lever for operating the left and right turning operations of the crane device 6, and a lever for operating the telescoping operations of the hoisting boom 7 and the folding boom 8. In addition to this, each control valve operation lever includes a lever for operating the winding-up and winding-down operations of the hook 14, and a lever for operating the hoisting operations of the hoisting boom 7 and the folding boom 8.

[0025] <Prime mover section> Hereinafter, with reference to FIGS. 1 to 3 and using FIGS. 4 and 5, the detailed configuration of the prime mover section 15 will be described. As shown in FIG. 4, the prime mover section 15 includes an engine 15a, a pressure oil supply device 15b, and a control valve 15c. The engine 15a, the pressure oil supply device 15b, and the control valve 15c are housed inside the housing.

[0026] The engine 15a is, for example, a diesel engine and constitutes a driving force generation source of the tower crane 1. As shown in FIG. 4, the pressure oil supply device 15b includes a hydraulic pump 60 driven by the engine 15a as a driving source, a left discharge port 61L, a right discharge port 61R, a main pipeline 62, a return pipeline 63, and a tank 64. The control valve 15c is a valve that switches and controls the oil passage of the pressure oil supplied from the pressure oil supply device 15b.

[0027] In addition, the control valve 15c includes a crane switching control valve 80, an accelerator cylinder 81, an outrigger switching control valve 82, a slewing switching control valve 83, a boom telescoping switching control valve 84, a winch switching control valve 85, and a boom hoisting switching control valve 86. Further, the control valve 15c includes a lateral outrigger cylinder switching valve 87, a vertical outrigger cylinder switching valve 88, a travel switching control valve 89, a first electromagnetic switching valve 820, a second electromagnetic switching valve 840, and a third electromagnetic switching valve 860. The crane switching control valve 80 is disposed between the main pipeline 62 and the return pipeline 63. The crane switching control valve 80 also includes a main relief valve (unloading valve) 180, a solenoid for unloading valve operation 181, and a hook fixing relief valve 182.

[0028] The solenoid 181 for unloading valve operation becomes ON or OFF according to the operation signal Uo (see Fig. 5) input from the controller 160. When the solenoid 181 for unloading valve operation is in the ON state, it opens the main relief valve 180 to communicate the main pipeline 62 and the return pipeline 63. In the example shown in Fig. 4, the pressure oil discharged from the hydraulic pump 60 is returned to the tank 64 via the return pipeline 63 without passing through the switching control valves other than the crane switching control valve 80 and the travel switching control valve 89 (the outrigger switching control valve 82, the slewing switching control valve 83, the boom telescoping switching control valve 84, the winch switching control valve 85, the boom hoisting switching control valve 86, the lateral outrigger cylinder switching valve 87, and the vertical outrigger cylinder switching valve 88). That is, the solenoid 181 for unloading valve operation in the ON state can set the operating state of the hydraulic pump 60 to an unloading state (no-load operation state) in which the pressure oil circulates without load.

[0029] The hook fixing relief valve 182 includes a hook relief solenoid 182a and a hook relief valve 182b. The hook relief solenoid 182a is turned on or off in response to an operation signal Hr (see FIG. 5) input from the controller 160. The operation signal Hr is a signal corresponding to the operation of the hook fixing switch in the operation unit 11 or the remote operation device 162. When the hook relief solenoid 182a is in the on state, it switches the oil passage of the pressure oil from the main pipe 62 to the oil passage through which the pressure oil flows to the hook relief valve 182b.

[0030] Here, the set relief pressure of the hook relief valve 182b is set to a low set pressure Ps. The low set pressure Ps is lower than the main set pressure Pm, which is the relief pressure during normal operation. Therefore, by turning on the hook relief solenoid 182a and operating the hook relief valve 182b, it is possible to limit the upper limit of the pressure of the pressure oil to the low set pressure Ps. As a result, while the hook fixing switch is in the on state, the hoisting operation pressure of the hook 14 can be limited to a low pressure, and damage to the hook storage bracket 17 that fixes the hook 14 can be prevented.

[0031] The accelerator cylinder 81 operates the piston rod of the accelerator cylinder 81 in response to an accelerator control signal Vctr (see FIG. 5) input from the controller 160. The accelerator control signal Vctr is a signal corresponding to the accelerator operation amount of the remote operation device 162 or the operation unit 11. The operation position signal L6 (see FIG. 5) of the piston rod is input to the controller 160. Thereby, the controller 160 can control the rotation speed of the engine 15a to a desired rotation speed according to the operation position (the operation position of the piston rod) of the accelerator cylinder 81. Note that the discharge amount of the pressure oil from the hydraulic pump 60 increases as the rotation speed of the engine 15a is increased by the accelerator operation. In addition, the accelerator cylinder 81 is provided with a differential transformer (not shown) that detects the switching position of the accelerator cylinder 81. As shown in FIG. 5, a switching position signal L6 indicating the switching position detected by the differential transformer is input to the controller 160. That is, the controller 160 can grasp the operation content (switching position) of the accelerator cylinder 81 based on the switching position signal L6.

[0032] The outrigger switching control valve 82 allows pressure oil to flow into the first electromagnetic switching valve 820 in response to the operating signal Actr1 (see Fig. 5) input from the controller 160. The operating signal Actr1 is a signal corresponding to the operation of the control valve operating lever or the operation signal Rctr (see Fig. 5) input from the remote operation device 162. Further, the outrigger switching control valve 82 is provided with a differential transformer (not shown) for detecting the switching position of the outrigger switching control valve 82. As shown in Fig. 5, the switching position signal L1 indicating the switching position detected by the differential transformer is input to the controller 160. That is, the controller 160 can grasp the operation content (switching position) of the outrigger switching control valve 82 based on the switching position signal L1.

[0033] The first electromagnetic switching valve 820 is a control valve that selects each of the horizontal outrigger cylinders 36RF to 36LR or each of the vertical outrigger cylinders 37RF to 37LR as the supply destination of the pressure oil flowing in from the outrigger switching control valve 82. Specifically, the first electromagnetic switching valve 820 switches the oil passage of the pressure oil to each of the horizontal outrigger cylinders 36RF to 36LR or each of the vertical outrigger cylinders 37RF to 37LR in response to the switching control signal Actr2 (see Fig. 5) input from the controller 160. The switching control signal Actr2 is a signal output in response to the operation of an outrigger switching switch (not shown) provided in the operation unit 11.

[0034] The slewing switching control valve 83 allows pressure oil to flow into the slewing hydraulic motor 30 in response to the operation amount of the control valve operating lever provided in the operation unit 11 or in response to the operating signal Tctr (see Fig. 5) input from the controller 160 in response to the operation of the remote operation device 162. In addition, the rotation switching control valve 83 is provided with a differential transformer (not shown) that detects the switching position of the rotation switching control valve 83. As shown in FIG. 5, a switching position signal L2 indicating the switching position detected by the differential transformer is input to the controller 160. That is, the controller 160 can grasp the operation details (switching position) of the rotation switching control valve 83 based on the switching position signal L2.

[0035] The boom telescoping switching control valve 84 allows pressure oil to flow into the second electromagnetic switching valve 840 according to the operation amount of the control valve operation lever of the operation unit 11, or according to the operation signal Bctr1 (see FIG. 5) input from the controller 160 according to the operation of the remote operation device 162. In addition, the boom telescoping switching control valve 84 is provided with a differential transformer (not shown) that detects the switching position of the boom telescoping switching control valve 84. As shown in FIG. 5, a switching position signal L3 indicating the switching position detected by the differential transformer is input to the controller 160. That is, the controller 160 can grasp the operation details (switching position) of the boom telescoping switching control valve 84 based on the switching position signal L3.

[0036] The second electromagnetic switching valve 840 is a control valve that selects the hoisting boom telescoping hydraulic cylinder 31 or the folding boom telescoping hydraulic cylinder 32 as the pressure oil supply destination. Specifically, the second electromagnetic switching valve 840 switches the pressure oil oil path to the hoisting boom telescoping hydraulic cylinder 31 or the folding boom telescoping hydraulic cylinder 32 according to the switching control signal Bctr3 (see FIG. 5) input from the controller 160. The switching control signal Bctr3 is a signal output according to the operation of the telescoping boom switching switch (not shown) of the operation unit 11 or the operation signal Rctr.

[0037] The winch switching control valve 85 allows pressure oil to flow into the winch hydraulic motor 33 according to the operation amount of the control valve operation lever of the operation unit 11, or according to the operation signal Wctr (see FIG. 5) output from the controller 160 according to the operation of the remote operation device 162. In addition, the winch switching control valve 85 is provided with a differential transformer (not shown) for detecting the switching position of the winch switching control valve 85. As shown in FIG. 5, a switching position signal L4 indicating the switching position detected by the differential transformer is input to the controller 160. That is, the controller 160 can grasp the operation content (switching position) of the winch switching control valve 85 based on the switching position signal L4.

[0038] The boom hoisting switching control valve 86 causes pressure oil to flow into the third electromagnetic switching valve 860 in response to an operation signal Bctr2 (see FIG. 5) input from the controller 160. The operation signal Bctr2 is a signal output according to the operation amount of the control valve operation lever of the operation unit 11 or the operation of the remote operation device 162. In addition, the boom hoisting switching control valve 86 is provided with a differential transformer (not shown) for detecting the switching position of the boom hoisting switching control valve 86. As shown in FIG. 5, a switching position signal L5 indicating the switching position detected by the differential transformer is input to the controller 160. That is, the controller 160 can grasp the operation content (switching position) of the boom hoisting switching control valve 86 based on the switching position signal L5.

[0039] The third electromagnetic switching valve 860 is a control valve that selects the hoisting boom hoisting hydraulic cylinder 34 or the folding boom hoisting hydraulic cylinder 35 as the oil supply destination of the pressure oil flowing in from the boom hoisting switching control valve 86. Specifically, the third electromagnetic switching valve 860 switches the oil path of the pressure oil to the hoisting boom hoisting hydraulic cylinder 34 or the folding boom hoisting hydraulic cylinder 35 in response to a switching control signal Bctr4 (see FIG. 5) input from the controller 160. The switching control signal Bctr4 is a signal output according to the operation of a hoisting boom switching switch (not shown) of the operation unit 11 by the manual operation of the operator or the operation signal Rctr.

[0040] In addition, a stop valve SB and a check valve CB are arranged in the oil path connecting the third electromagnetic switching valve 860 and the hoisting boom hoisting hydraulic cylinder 34. The stop valve SB is opened or closed by manual operation by an operator or the like. In the open state of the stop valve SB, the oil passage for pressure oil from the third electromagnetic switching valve 860 to the hydraulic cylinder 34 for raising and lowering the boom is opened. Therefore, in the open state of the stop valve SB, the oil passage between the hydraulic pump 60 forming a pressure oil supply source for supplying pressure oil to the hydraulic cylinder 34 for raising and lowering the boom and the hydraulic cylinder 34 for raising and lowering the boom is opened.

[0041] On the other hand, in the closed state of the stop valve SB, the oil passage for pressure oil from the third electromagnetic switching valve 860 to the hydraulic cylinder 34 for raising and lowering the boom is closed. Therefore, in the closed state of the stop valve SB, the oil passage between the hydraulic pump 60 and the hydraulic cylinder 34 for raising and lowering the boom is closed. That is, by manually operating the stop valve SB to the closed state, it becomes possible to restrict the displacement of the boom 7 in the direction in which the boom 7 is displaced by extending the hydraulic cylinder 34 for raising and lowering the boom. The check valve CB is arranged in parallel with the stop valve SB and prevents the movement of pressure oil from the hydraulic cylinder 34 for raising and lowering the boom to the third electromagnetic switching valve 860. Therefore, the check valve CB prevents the backflow of pressure oil from the hydraulic cylinder 34 for raising and lowering the boom to the hydraulic pump 60.

[0042] The lateral outrigger cylinder switching valve 87 is a control valve that selects whether to supply pressure oil to each of the lateral outrigger cylinders 36RF to 36LR. Specifically, the lateral outrigger cylinder switching valve 87 switches the oil passage for pressure oil to each of the lateral outrigger cylinders 36RF to 36LR according to the operation signals Actr3 to 6 (see FIG. 5) input from the controller 160. The operation signals Actr3 to 6 are signals output according to the operation of a lateral outrigger cylinder selection switch (not shown) provided in the operation unit 11.

[0043] The vertical outrigger cylinder switching valve 88 is a control valve that selects whether to supply pressure oil to each vertical outrigger cylinder 37RF to 37LR. Specifically, the vertical outrigger cylinder switching valve 88 switches the oil passage of the pressure oil to each vertical outrigger cylinder 37RF to 37LR according to the operation signals Actr7 to 10 (see FIG. 5) input from the controller 160. The operation signals Actr7 to 10 are signals output according to the operation of a vertical outrigger cylinder selection switch (not shown) provided in the operation unit 11.

[0044] The traveling switching control valve 89 is supplied with the pressure oil discharged from the hydraulic pump 60. When the traveling operation lever is in the neutral state, the pressure oil supplied to the traveling switching control valve 89 passes through the traveling switching control valve 89 and flows into the main pipeline 62, and is supplied through the main pipeline 62 toward the control valve 15c. Also, the pressure oil discharged from the hydraulic pump 60 returns to the tank 64 through the return pipeline 63.

[0045] <Control box> Hereinafter, with reference to FIGS. 1 to 4 and using FIG. 5, the detailed configuration of the control box 16 will be described. The control box 16 houses the controller 160 shown in FIG. 5. Further, a code display unit (not shown) capable of displaying a numerical code indicating the operating state of the tower crane 1 is attached to the control box 16. The code display unit is formed using, for example, a 7-segment LED (Light Emitting Diode) capable of displaying two-digit numbers. The numbers displayed on the 7-segment LED are displayed according to a command signal output from the controller 160.

[0046] A receiver 161 is connected to the controller 160 via a signal line (not shown). The receiver 161 is disposed on the upper part of the control box 16. Further, the receiver 161 receives a remote control signal Rctr wirelessly transmitted from the remote control device 162. Then, the receiver 161 inputs the received remote control signal Rctr to the controller 160 via a signal line.

[0047] Although not shown in the figure, the remote control device 162 is configured to be capable of performing operations equivalent to those of the operation levers and operation switches of the operation unit 11 by various operation levers and various operation switches provided on the housing of the remote control device 162. Further, the remote control device 162 is configured to wirelessly transmit a remote control signal Rctr corresponding to the operations of the operation levers and operation switches. Thereby, the remote control device 162 can remotely operate the crane. Further, operation signals Ctr from the operation unit 11, remote control signals Rctr from the remote control device 162, switching position signals L1 to L6 from various switching control valves 82 to 86 and the accelerator cylinder 81, etc. are input to the controller 160. Then, the controller 160 operates and controls various electrical devices, such as solenoid valves for oil passage switching provided in the tower crane 1, according to the input signals.

[0048] Although not shown in the figure, the controller 160 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a timer for time measurement. The CPU performs various arithmetic processes based on a predetermined control program. The ROM stores various data including the control program. The RAM stores data read from the ROM, etc. and arithmetic results necessary in the arithmetic process of the CPU. Furthermore, the controller 160 includes an input / output I / F (interface) and various internal and external buses for data transfer. The input / output I / F mediates data input and output to / from each device including the operation unit 11, the receiver 161, the remote control device 162, the control valve 15c, etc. The various internal and external buses connect between the CPU, the ROM, the RAM, and the timer. Also, each device is connected to the various internal and external buses via the input / output I / F.

[0049] When the power is turned on, system programs such as BIOS stored in the ROM or the like load various control programs stored in the ROM in advance into the RAM. Further, the CPU performs arithmetic processing by making full use of various resources according to the instructions described in the program loaded into the RAM, thereby realizing each function for operating and controlling each device in software. In addition, for example, the load applied to the folding boom 8 detected by the load detection unit 90 is input to the controller 160 via CAN (Controller Area Network) communication. Note that the load applied to the folding boom 8 is a value corresponding to the lifting load of the tower crane 1. The load detection unit 90 is formed using, for example, a load cell.

[0050] Furthermore, for example, the angle of the folding boom 8 detected by the folding boom angle detection unit 92 is input to the controller 160 via CAN communication. The folding boom angle detection unit 92 is formed using, for example, a potentiometer that detects the displacement of the hydraulic cylinder 32 for extending and retracting the folding boom. In addition, for example, the detection signal SW1 from the first proximity switch 56R, the detection signal SW2 from the second proximity switch 57R, and the detection signal SW3 from the third proximity switch 58R are input to the controller 160 via CAN communication. Similarly, the detection signal SW4 from the fourth proximity switch 56L, the detection signal SW5 from the fifth proximity switch 57L, and the detection signal SW6 from the sixth proximity switch 58L are input.

[0051] The detection signal SW1 and the detection signal SW4 are signals output when the angle regulating pin (not shown) is inserted into the pin hole (not shown) formed at the position corresponding to the standing angle of 95° of the lifting boom 7 among the column 5 and the standing angle regulating member 20 when the standing angle of the lifting boom 7 is set to 95°. The detection signals SW2 and SW5 are signals output in a state where an angle regulation pin (not shown) is inserted into a pin hole (not shown) formed at a position corresponding to the 90° upright angle of the heaving boom 7, among the column 5 and the upright angle regulation member 20, when the upright angle of the heaving boom 7 is set to 90°. The detection signals SW2 and SW5 are signals output in a state where an angle regulation pin (not shown) is inserted into a pin hole (not shown) formed at a position corresponding to the 85° upright angle of the heaving boom 7, among the column 5 and the upright angle regulation member 20, when the upright angle of the heaving boom 7 is set to 85°.

[0052] Note that the upright angle regulation member 20 is configured such that, in the stored state of the heaving boom 7, two plates are bent in a "く" shape around the connecting portion. And, for example, when the upright angle of the heaving boom 7 is 95°, while raising the stored heaving boom 7, the shape changes around the connecting portion, and when the upright angle of the heaving boom 7 reaches 95°, the shape changes linearly. At this time, it is stretched diagonally between the column 5 and the heaving boom 7, and since the two plates do not displace with respect to the extension operation of the heaving boom hoisting hydraulic cylinder 34, the upright angle of the heaving boom 7 is regulated to 95°. The same applies to the case where the upright angle of the heaving boom 7 is 90° and the case where the upright angle of the heaving boom 7 is 85°.

[0053] <Hydraulic actuator> Hereinafter, with reference to FIGS. 1 to 5, a hydraulic actuator (swivel hydraulic motor 30, heaving boom telescopic hydraulic cylinder 31, folding boom telescopic hydraulic cylinder 32, winch hydraulic motor 33, heaving boom hoisting hydraulic cylinder 34, folding boom hoisting hydraulic cylinder 35, traveling motor 38) will be described. As shown in FIG. 4, each of the hydraulic actuators is operated by the pressure oil supplied from the pressure oil supply device 15b via the control valve 15c.

[0054] The slewing hydraulic motor 30 is a hydraulic actuator for slewing the column 5. The hydraulic cylinder 31 for telescoping the luffing boom is a hydraulic actuator for telescoping the luffing boom 7. The hydraulic cylinder 32 for telescoping the folding boom is formed using, for example, tilt cylinders, and is a hydraulic actuator for telescoping the folding boom 8. The winch hydraulic motor 33 is a hydraulic actuator for winding up and winding down the winch 12.

[0055] The hydraulic cylinder 34 for luffing the luffing boom is formed using, for example, derrick cylinders, and is a hydraulic actuator for telescoping the luffing boom 7. Further, as shown in FIG. 4, the hydraulic cylinder 34 for luffing the luffing boom is composed of a pair of hydraulic cylinders, namely, a first hydraulic cylinder 34R for luffing the luffing boom and a second hydraulic cylinder 34L for luffing the luffing boom. The hydraulic cylinder 35 for luffing the folding boom is formed using, for example, tilt cylinders, and is a hydraulic actuator for telescoping the folding boom 8. Further, the hydraulic cylinder 35 for luffing the folding boom is composed of a pair of hydraulic cylinders, namely, a first hydraulic cylinder 35R for luffing the folding boom and a second hydraulic cylinder 35L for luffing the folding boom.

[0056] The traveling motor 38 is a hydraulic actuator for driving the traveling device 3. Further, as shown in FIG. 4, the traveling motor 38 includes a left traveling motor 38L and a right traveling motor 38R. The left traveling motor 38L is a motor for rotating the left crawler belt mounted on the traveling device 3. The right traveling motor 38R is a motor for rotating the right crawler belt mounted on the traveling device 3. The left traveling motor 38L and the right traveling motor 38R are each independently operated by individually supplying pressure oil from the pressure oil supply device 15b via the traveling switching control valve 89. As a result, the tower crane 1 operates the pressure oil supply device 15b and simultaneously moves the pair of left and right travel operation levers forward or backward to drive the traveling device 3, enabling it to travel in the forward or backward direction. Also, when turning right or left, by individually moving the pair of left and right travel operation levers forward or backward, the corresponding left and right crawlers are individually rotated, and turning is possible due to the speed difference generated between the left and right crawlers.

[0057] (Erecting operation of the luffing boom 7) Hereinafter, the erecting operation in which the luffing boom 7 transitions from the boom retracted state to the erected state when viewed from the right side in the vehicle width direction will be described. In the embodiment, the case where three types of erecting angles (95°, 90°, 85°) are set as the erecting angle of the luffing boom 7 will be described. When erecting the luffing boom 7, the third electromagnetic switching valve 860 is switched to the side of the luffing boom hydraulic cylinder 34. The switching operation of the third electromagnetic switching valve 860 is performed by the operator switching the luffing boom switching switch (not shown) of the operation unit 11 to the luffing boom operation mode side. Then, the erecting angle of the luffing boom 7 is selected from the three types of erecting angles to an erecting angle suitable for the working environment.

[0058] As shown in FIG. 2, when the erecting angle is 90°, the luffing boom 7 stands upright without tilting in the front-rear direction. When the erecting angle is 95°, the luffing boom 7 stands up with a 5° tilt forward. When the erecting angle is 85°, the luffing boom 7 stands up with a 5° tilt backward. In FIG. 2, the erected state of the luffing boom 7 at the erecting angle of 95° is shown by a solid line, and the erected states of the luffing boom 7 at the erecting angles of 90° and 85° are shown by a two-dot chain line.

[0059] Therefore, with the standing angle of 90° as the reference, when the standing angle is 95°, the tip of the folding boom 8 reaches further forward than in the state of the standing angle of 90°. Therefore, during the lifting operation, it is possible to lift the load further forward than in the state of the standing angle of 90°. Also, when the standing angle is 85°, the luffing boom 7 is positioned directly above the swivel center of the column 5. Therefore, when the tower crane 1 is placed inside a building and the boom is protruded through an opening provided in the roof for work, it is possible to reduce the diameter of the opening. Also, when the standing angle is 85°, it is possible to lift a load with a mass larger than that in the states of the standing angles of 95° and 90°. Note that the tower crane 1 performs a handling operation by lifting a load via the hook 14, for example, in the working posture shown in FIG. 3. Therefore, when the load is lifted, a force that pulls forward in the vehicle longitudinal direction is applied to the luffing boom 7. Note that FIG. 3 shows the state in which the luffing boom 7 and the folding boom 8 are extended to the maximum.

[0060] To set the tower crane 1 to the working posture shown in FIG. 3, first, the traveling mode is implemented in the traveling posture shown in FIG. 1 to move the tower crane 1 to the work site. Note that the traveling mode is a mode in which the tower crane 1 is traveled by the traveling device 3. Next, the outrigger mode is implemented to install each outrigger 9RF to 9LR. Note that the outrigger mode is a mode in which each lateral outrigger cylinder 36RF to 36LR and each lateral outrigger cylinder 36RF to 36LR are driven. Thereafter, the Z mode is implemented to raise the luffing boom 7, and further, the folding boom 8 is raised to an elevation angle above the horizontal to set the tower crane 1 to the working posture. Note that the Z mode is a mode in which the luffing boom 7 and the folding boom 8 are displaced according to the operation by the operator. Also, after the work using the crane device 6 is completed, the Z mode is implemented to store the luffing boom 7 and the folding boom 8 deployed in the working posture. Thereafter, the escape mode is implemented to automatically travel the tower crane 1 by the traveling device 3 to escape the tower crane 1 from the work site. Note that the escape mode is a mode in which the traveling device 3 automatically travels.

[0061] (Automatic pressurization process) Hereinafter, with reference to FIGS. 1 to 5 and using FIG. 6, the automatic pressurization process executed by the controller 160 will be described. The automatic pressurization process is a process for controlling the pressure oil supplied to the hydraulic cylinder 34 for the undulating boom undulation, and is a process repeatedly performed at a predetermined sampling period. In addition, the automatic pressurization process is a process of shifting from the work mode to the automatic pressurization mode when the automatic pressurization condition, which is a preset condition, is satisfied during the execution of the work mode. The work mode is a mode in which, after the raising operation of the undulating boom 7 is completed, in response to the operation of the folding boom 8 by the operator, pressure oil is supplied to the hydraulic cylinder 32 for the telescopic movement of the folding boom and the hydraulic cylinder 35 for the undulation of the folding boom.

[0062] The automatic pressurization mode is a mode in which pressure oil is supplied to the hydraulic cylinder 34 for the undulation of the undulating boom so as to extend the hydraulic cylinder 34 for the undulation of the undulating boom, giving priority over the supply of pressure oil to the hydraulic cylinder 32 for the telescopic movement of the folding boom and the hydraulic cylinder 35 for the undulation of the folding boom according to the operation of the folding boom 8 by the operator. During the execution of the automatic pressurization mode, even if a remote operation signal Rctr is transmitted from the remote operation device 162, the operation according to the remote operation signal Rctr is not performed. Also, during the execution of the automatic pressurization mode, manual operation is made impossible in order to maintain the positions of the spools respectively provided in the outrigger switching control valve 82, the slewing switching control valve 83, the boom telescopic switching control valve 84, the winch switching control valve 85, and the boom undulation switching control valve 86 at the neutral positions.

[0063] As shown in FIG. 6, the automatic pressurization process is executed during the execution of the main loop (a process for controlling various devices in a state where the tower crane 1 is operating while the engine 15a is being driven). First, in step S10, it is determined whether or not the work mode is being executed. If it is determined that the work mode is in progress (Yes), the process proceeds to step S11. On the other hand, if it is determined that the work mode is not in progress (No), the process returns to the main loop.

[0064] Note that "if it is determined that the work mode is not in progress" means that any of the outrigger mode, escape mode, Z mode, or travel mode is in progress. In step S11, a timer measures the time elapsed since the transition to the work mode or the time elapsed since the previous transition to the automatic pressurization mode. Further, in step S11, it is determined whether or not a preset first time has elapsed since the transition to the work mode, or whether or not a preset second time has elapsed since the previous transition to the automatic pressurization mode.

[0065] Note that in the embodiment, as an example, the case where the first time and the second time are both 30 minutes will be described. Therefore, in step S11, it is determined whether or not the time elapsed since the transition to the work mode or the time elapsed since the previous transition to the automatic pressurization mode has reached 30 minutes. If it is determined that the time elapsed since the transition to the work mode has reached 30 minutes or the time elapsed since the previous transition to the automatic pressurization mode has reached 30 minutes (Yes), the process proceeds to step S12. On the other hand, if it is determined that the time elapsed since the transition to the work mode has not reached 30 minutes and the time elapsed since the previous transition to the automatic pressurization mode has not reached 30 minutes (No), the process returns to the main loop. That is, the automatic pressurization condition includes a condition that is satisfied when the first time has elapsed since the transition to the work mode. In addition to this, the automatic pressurization condition includes a condition that is satisfied when the second time has elapsed since the transition to the automatic pressurization mode.

[0066] In step S12, it is determined by a timer whether the time during which the operation unit 11 or the remote operation device 162 is not operated continues for a preset third time. That is, in step S12, it is determined whether the time during which no operation is performed by the operator continues for the third time during the execution of the work mode. In the embodiment, as an example, the case where the third time is set to 30 seconds will be described. Therefore, in step S12, it is determined whether the time during which the operation unit 11 or the remote operation device 162 is not operated continues for 30 seconds. If it is determined that the time during which the operation unit 11 or the remote operation device 162 is not operated continues for 30 seconds (Yes), the process proceeds to step S13. On the other hand, if it is determined that the time during which the operation unit 11 or the remote operation device 162 is not operated is less than 30 seconds (No), the process returns to the main loop. That is, the automatic pressurization condition includes a condition that is established when the time during which no operation is performed by the operator continues for the third time during the execution of the work mode.

[0067] In step S13, it is determined whether the load applied to the folding boom 8 is equal to or less than a preset load. That is, in step S13, it is determined whether the lifting load of the tower crane 1 is equal to or less than a preset load. In the embodiment, as an example, the case where the preset load is assumed to be 30 kg, which is equivalent to the unloaded state, will be described. Therefore, in step S13, it is determined whether the load applied to the folding boom 8 is 30 kg or less. And when it is determined that the load applied to the folding boom 8 is 30 kg or less (Yes), the process proceeds to step S14. On the other hand, when it is determined that the load applied to the folding boom 8 exceeds 30 kg (No), the process returns to the main loop. That is, the automatic pressurization condition includes a condition that is satisfied when the load applied to the folding boom 8 is less than or equal to a preset load. Therefore, the condition that is satisfied when the load applied to the folding boom 8 is less than or equal to the preset load is a condition that is satisfied when the pressure applied in the direction opposite to the direction in which the hydraulic cylinder 35 for folding boom undulation contracts decreases to less than or equal to a preset constant pressure.

[0068] In step S14, it is determined whether a stop command for the engine 15a has been input from the remote control device 162. And when it is determined that a stop command for the engine 15a has been input from the remote control device 162 (Yes), the process returns to the main loop. On the other hand, when it is determined that a stop command for the engine 15a has not been input from the remote control device 162 (No), the process proceeds to step S15. Therefore, in the automatic pressurization process, the automatic pressurization mode is not entered while the engine 15a is stopped by a command input from the remote control device 162.

[0069] In step S15, it is determined whether an abnormal state has occurred. Note that the abnormal state includes a state in which the safety device is released and the work mode is being executed, or a state in which an error has occurred and the work mode is being executed. In addition, the abnormal state includes a state in which the Z mode is being executed, the outrigger mode is being executed, the traveling mode is being executed, the escape mode is being executed, the emergency operation switch is ON, the safety device release switch is ON, and a stop command has occurred. The emergency operation switch ON means a state in which the emergency operation switch is operated and emergency operation is permitted. The safety device release switch ON means a state in which the safety device release switch is operated and the safety device is released. The stop command is a command to stop the operation of the tower crane 1.

[0070] If it is determined that an abnormality has occurred (Yes), the process returns to the main loop. On the other hand, if it is determined that no abnormality has occurred (No), the process proceeds to step S16. That is, in the automatic pressurization process, during the execution of the Z mode, during the execution of the outrigger mode, during the execution of the traveling mode, during the execution of the escape mode, when the emergency operation switch is ON, when the safety device release switch is ON, or when a stop command is issued, the process does not shift to the automatic pressurization mode.

[0071] In step S16, the process shifts from the work mode to the automatic pressurization mode. Then, the process proceeds to step S17. Also, during the execution of the automatic pressurization mode, the digital code indicating that the automatic pressurization mode is being executed is displayed by lighting "24" on the 7-segment LED. Here, as described above, the check valve CB is arranged in parallel with the stop valve SB and prevents the backflow of the pressure oil from the hydraulic cylinder 34 for the boom elevation to the hydraulic pump 60. That is, the stop valve SB and the check valve CB form a bypass circuit for sending the pressure oil to the hydraulic cylinder 34 for the boom elevation in the automatic pressurization mode when the stop valve SB is in the closed state.

[0072] In step S17, it is determined whether or not a preset fourth time has elapsed since the process shifted from the work mode to the automatic pressurization mode. In the embodiment, as an example, the case where the fourth time is set to 2 seconds will be described. Therefore, in step S17, it is determined whether or not the time elapsed since the process shifted from the work mode to the automatic pressurization mode has reached 2 seconds. If it is determined that 2 seconds have elapsed since the process shifted from the work mode to the automatic pressurization mode (Yes), the process proceeds to step S22. On the other hand, if it is determined that 2 seconds have not elapsed since the process shifted from the work mode to the automatic pressurization mode (No), the process proceeds to step S18.

[0073] Note that the 2 seconds determined in step S17 is the time necessary and sufficient to supply pressure oil to the boom lifting hydraulic cylinder 34 so that the internal pressure of the boom lifting hydraulic cylinder 34 is restored and the erected state of the boom 7 is restored. In step S18, regardless of the operation state of the boom switching switch, the mode is switched to the boom lifting operation mode. That is, during the execution of the automatic pressurization mode, regardless of the operation state of the boom switching switch, it is forcibly switched to the boom lifting operation mode among the folding boom lifting operation mode and the boom lifting operation mode. Then, the process proceeds to step S19.

[0074] In step S19, a command signal for supplying pressure oil to extend the boom lifting hydraulic cylinder 34 is output to the boom lifting hydraulic cylinder 34, and all command signals output to other hydraulic actuators are set to "0". That is, in step S19, an operation command is output only to the boom 7 among the plurality of hydraulic actuators. Then, the process proceeds to step S20. In step S20, it is determined whether or not a manual operation has been performed by the operator. If it is determined that a manual operation has been performed by the operator (Yes), the process proceeds to step S21. On the other hand, if it is determined that no manual operation has been performed by the operator (No), the process proceeds to step S17.

[0075] In step S21, the supply of pressure oil to the boom lifting hydraulic cylinder 34 is interrupted. Further, by lighting "25" on the 7-segment LED, a numeric code indicating a warning for the manual operation performed during the execution of the automatic pressurization mode is displayed. Then, the process proceeds to step S22. In step S22, the automatic pressurization mode is terminated. Then, the process proceeds to step S23. In step S23, the operation amount of the boom 7 is set to "0". That is, in step S23, the operation of the boom 7 is stopped. Then, the process proceeds to step S24. In step S24, it is switched to a state where the operator can operate the folding boom 8. Then, the process returns to the main loop.

[0076] In addition, in the automatic pressurization process, in addition to the processes from step S10 to step S20, when the angle of the folding boom 8 detected by the folding boom angle detection unit 92 increases by a preset angle (for example, 5°) during the execution of the automatic pressurization mode, the supply of pressure oil to the boom lifting hydraulic cylinder 34 for the undulating boom is interrupted. In addition, until the automatic pressurization mode is terminated, by blinking "25" on the 7-segment LED, a numeric code indicating a warning for the increase in the angle of the folding boom 8 is displayed. The reason for detecting that the angle of the folding boom 8 has increased is that when pressure oil is supplied to the boom lifting hydraulic cylinder 34 for the undulating boom so as to extend the boom lifting hydraulic cylinder 34 for the undulating boom, relatively, the angle of the folding boom 8 shifts in the falling direction.

[0077] Also, the reason for interrupting the supply of pressure oil to the boom lifting hydraulic cylinder 34 for the undulating boom when the angle of the folding boom 8 increases is that if the solenoid valve for switching the oil path to the boom lifting hydraulic cylinder 34 for the undulating boom and the folding boom lifting hydraulic cylinder 35 does not operate due to a power failure or the like, when the automatic pressurization mode is implemented, the folding boom 8 may rise unexpectedly, increasing the risk of work. As described above, in the automatic pressurization process, when the boom lifting switching control valve 86 detects the rising operation of the folding boom 8 during the execution of the automatic pressurization mode, it stops the supply of pressure oil to the boom lifting hydraulic cylinder 34 for the undulating boom by the automatic pressurization mode.

[0078] In addition, in the automatic pressurization process, in addition to the processes from step S10 to step S20, when the undulating angle of the undulating boom 7 is equal to or greater than a preset angle (for example, 85°) and the engine 15a is stopped, when the engine 15a starts and the power take-off operates, the operation mode is shifted to the automatic pressurization mode. Therefore, the automatic pressurization condition includes the condition that the undulation angle of the undulation boom 7 is equal to or greater than a preset angle, and that the engine 15a, which is the drive source of the pressure oil supply device for supplying pressure oil, is stopped, and is established when the engine 15a starts and the power take-off operates.

[0079] Furthermore, in the automatic pressurization process, in addition to the processes from step S10 to step S20, when the start of the stopped engine 15a is performed by the remote operation of the operator by the remote operation device 162, the operation mode is shifted to the automatic pressurization mode. Therefore, the automatic pressurization condition includes the condition that is established when the start of the stopped engine 15a is performed by the remote operation of the operator by the remote operation device 162. Note that during the implementation of the automatic pressurization mode, when an operation input is made by the operator, it may be configured to cancel both the operation input by the operator and the supply of pressure oil in the automatic pressurization mode as error handling.

[0080] <Correspondence between Claims and Embodiments> The tower crane 1 corresponds to the working machine. The undulation boom 7 corresponds to the first component member that is displaceably attached to the base of the tower crane 1. The undulation boom undulation hydraulic cylinder 34 corresponds to the first hydraulic cylinder that displaces the undulation boom 7 by extending or contracting. The folding boom 8 corresponds to the second component member that is attachable to the tip of the undulation boom (first component member) so as to be undulatable. The folding boom telescopic hydraulic cylinder 32 and the folding boom undulation hydraulic cylinder 35 correspond to the second hydraulic cylinder that is a hydraulic cylinder different from the first hydraulic cylinder and displaces the folding boom 8 by extending or contracting. The boom undulation switching control valve 86 corresponds to the hydraulic control unit. The controller 160, the undulation boom undulation hydraulic cylinder 34, and the boom undulation switching control valve 86 correspond to the hydraulic equipment control device that controls the operation of the undulation boom 7.

[0081] <Actions and Effects of the Embodiment> The hydraulic equipment control device according to the embodiment can achieve the following operations and effects. (1) It includes a hydraulic cylinder that displaces a component by extending or contracting, and a hydraulic control unit that controls the pressure oil supplied to the hydraulic cylinder. During the execution of the working mode in which the hydraulic control unit supplies pressure oil to the hydraulic cylinder according to the operation of the component by the operator, when the automatically pressurizing condition, which is a preset condition, is satisfied, it shifts to the automatically pressurizing mode. The automatically pressurizing mode is a mode in which pressure oil is supplied to the hydraulic cylinder so as to extend the hydraulic cylinder with priority over the supply of pressure oil to the hydraulic cylinder according to the operation of the component by the operator. In addition, the component includes a first component that is displaced by a first hydraulic cylinder to which pressure oil is supplied in the automatically pressurizing mode, and a second component that is displaced by a second hydraulic cylinder that is a hydraulic cylinder different from the first hydraulic cylinder and to which pressure oil is supplied according to the operation by the operator during the execution of the working mode.

[0082] Therefore, even when the internal pressure of the first hydraulic cylinder has decreased, when the automatically pressurizing condition is satisfied, pressure oil is supplied to the first hydraulic cylinder in the same direction as when the first hydraulic cylinder is extended. As a result, even when the internal pressure of the first hydraulic cylinder has decreased, by supplying pressure oil to the first hydraulic cylinder in the same direction as when the first hydraulic cylinder is extended, the internal pressure of the first hydraulic cylinder is restored. As a result, it is possible to suppress the occurrence of behavior different from the intention of the operator in the first component.

[0083] (2) It includes a stopper member that restricts the displacement of the first component in the direction in which the first component is displaced by extending the first hydraulic cylinder. As a result, it is possible to prevent a load in the pulling direction from being applied to the first hydraulic cylinder at the stroke end of the first hydraulic cylinder, restrict excessive displacement of the first component, and suppress damage to the first component.

[0084] (3) The first component member is the tilting boom 7 that is tiltably attached to the base, and the second component member is the folding boom 8 that is pivotably attached to the tip of the tilting boom 7. As a result, it becomes possible to suppress the occurrence of behavior different from the operator's intention in the tilting boom 7.

[0085] (4) The automatic pressurization condition includes a condition that is established when the load applied to the folding boom 8 is equal to or less than a preset load. As a result, when the lifting load of the tower crane 1 is large, it does not shift to the automatic pressurization mode, so it becomes possible to improve safety.

[0086] (5) The hydraulic control unit does not shift to the automatic pressurization mode when a stop command for the folding boom 8 is automatically output during the execution of the working mode. As a result, when the operation of the crane device 6 is not permitted, the tilting boom tilting hydraulic cylinder 34 is not extended, so it becomes possible to improve the safety of operations and the like.

[0087] (6) When the hydraulic control unit detects the raising operation of the folding boom 8 during the execution of the automatic pressurization mode, it stops supplying pressure oil to the first hydraulic cylinder by the automatic pressurization mode. As a result, even when a malfunction occurs in the solenoid valve for switching the oil passage to the tilting boom tilting hydraulic cylinder 34 and the folding boom tilting hydraulic cylinder 35, it becomes possible to prevent a malfunction of the folding boom 8 caused by the malfunction of the solenoid valve.

[0088] (7) The automatic pressurization condition includes a condition that is established when the tilting angle of the tilting boom 7 is equal to or greater than a preset angle and the engine 15a is stopped, and when the engine 15a starts and the power take-off operates. As a result, even when the engine 15a restarts and the power take-off operates, it becomes possible to suppress an increase in the tilting angle of the tilting boom 7 from a preset angle, so it becomes possible to improve safety.

[0089] (8) The automatic pressurization condition includes a condition that is established when the start of the stopped engine 15a is performed by the remote operation of the operator by the remote operation device 162. As a result, it becomes possible to improve safety.

[0090] (9) The automatic pressurization condition includes a condition that is established when a preset first time has elapsed after shifting to the work mode. As a result, when the first time has elapsed after shifting to the work mode, the pressure oil is supplied to the first hydraulic cylinder so as to extend the first hydraulic cylinder, giving priority over the supply of pressure oil to the second hydraulic cylinder in response to the operation of the second component by the operator while the internal pressure of the first hydraulic cylinder is decreasing. Thereby, it becomes possible to suppress the occurrence of behavior different from the intention of the operator in the first component.

[0091] (10) The automatic pressurization condition includes a condition that is established when a preset second time has elapsed after shifting to the automatic pressurization mode. As a result, when the second time has elapsed after shifting to the automatic pressurization mode, the pressure oil is supplied to the first hydraulic cylinder so as to extend the first hydraulic cylinder, giving priority over the supply of pressure oil to the second hydraulic cylinder in response to the operation of the second component by the operator while the internal pressure of the first hydraulic cylinder is decreasing. Thereby, it becomes possible to suppress the occurrence of behavior different from the intention of the operator in the first component.

[0092] (11) The automatic pressurization condition includes a condition that is established when the time during which no operation is performed by the operator during the execution of the work mode continues for a preset third time. As a result, it becomes possible to prevent the occurrence of behavior different from the intention of the operator in the boom 7 during the operation of the folding boom 8 by the operator, and it becomes possible to prevent the cargo handling work from being hindered.

[0093] A hydraulic pump 60 that supplies pressure oil to a first hydraulic cylinder and a stop valve SB that opens or closes an oil passage between the hydraulic pump 60 and the first hydraulic cylinder are provided. A check valve CB is arranged in parallel with the stop valve SB and prevents the backflow of the pressure oil from the first hydraulic cylinder to the hydraulic pump 60. In addition, after displacing the first component member, the hydraulic control unit closes the oil passage between the hydraulic pump 60 and the first hydraulic cylinder by the stop valve SB. As a result, after displacing the first component member, the operator or the like manually operates to close the oil passage between the hydraulic pump 60 and the first hydraulic cylinder by the stop valve SB. In addition, the check valve CB can prevent the backflow of the pressure oil from the first hydraulic cylinder to the hydraulic pump 60. Thereby, after displacing the first component member, it is possible to prevent the first component member from being further displaced, and it is possible to improve safety.

[0094] <Modification> (1) In the embodiment, the tower crane 1 is described as an example of a working machine provided with a hydraulic equipment control device, but it is not limited thereto. That is, the hydraulic equipment control device can be applied not only to the tower crane 1 but also to other cranes and various working machines other than cranes, as long as it has a component member that performs a lifting operation such as a lifting boom 7 and stands in an upright state during work. Note that the working machine includes those that perform work (for example, work of illuminating an object) in a state of being moved to and installed at a destination, such as a lighting device, and those that perform work (for example, work of supporting an object) in a stationary state.

[0095] (2) In the embodiment, the lifting boom 7 is described as an example of the component member, but it is not limited thereto. That is, the component member may be a member that is displaced by the extension or contraction of the hydraulic cylinder. For example, it may be a folding boom 8. In addition, the component member may be, for example, an outrigger device 9 provided in the tower crane 1. Note that these outrigger devices 9 usually do not have a stopper member. However, for example, the outrigger devices 9 may be provided with a stopper member that restricts movement in the direction in which the constituent members are displaced when each of the horizontal outrigger cylinders 36RF to 36LR and each of the vertical outrigger cylinders 37RF to 37LR provided in the outrigger device 9 are extended. Therefore, the constituent members have been described with reference to the outrigger device 9 provided in the tower crane 1, but are not limited thereto. For example, they are also applicable to outrigger devices provided in luffing cranes.

[0096] (3) In the embodiment, the hydraulic equipment control device is configured to include a stop valve SB as a stopper member that restricts the displacement of the luffing boom 7 in the direction in which the luffing boom 7 is displaced by extending the luffing boom hydraulic cylinder 34. However, the present invention is not limited thereto. That is, for example, as the stopper member, a standing angle regulating member 20 (lock plate) that regulates the standing angle of the luffing boom 7 may be used.

[0097] (4) In the embodiment, the stop valve SB is configured to be in an open state or a closed state by manual operation by an operator or the like. However, the present invention is not limited thereto. That is, the stop valve SB may be configured to be in an open state or a closed state by a switching control signal (not shown) input from the controller 160. In this case, by inputting a switching control signal from the controller 160 to close the stop valve SB, it becomes possible to restrict the displacement of the luffing boom 7 in the direction in which the luffing boom 7 is displaced by extending the luffing boom hydraulic cylinder 34. With this configuration, the controller 160, the luffing boom hydraulic cylinder 34, and the boom luffing switching control valve 86 form a stopper member that restricts the displacement of the luffing boom 7 in the direction in which the luffing boom 7 is displaced by extending the luffing boom hydraulic cylinder 34.

[0098] Also, the timing at which the controller 160 outputs a switching control signal to close the stop valve SB is after the state of the heaving boom 7 is changed from a stored state or the like to an erected state at a preset erection angle. That is, after displacing the heaving boom 7, the controller 160 closes the oil passage between the hydraulic pump 60 and the hydraulic cylinder 34 for heaving the heaving boom by the stop valve SB. When the stop valve SB is configured to be in an open state or a closed state by a switching control signal input from the controller 160, it is possible to configure the system without a check valve CB by only opening the stop valve SB at the timing of automatic pressurization. This makes it possible to simplify the configuration.

Explanation of Signs

[0099] 1 Tower crane (working machine) 2 Chassis frame 3 Travel device 4 Base 5 Column 6 Crane device 7 Heaving boom 8 Folding boom 11 Operation unit 15a Engine 15b Pressure oil supply device 15c Control valve 32 Hydraulic cylinder for extending and retracting the folding boom 34 Hydraulic cylinder for heaving the heaving boom 35 Hydraulic cylinder for heaving the folding boom 60 Hydraulic pump 62 Main pipeline 63 Return pipeline 64 Tank 80 Switching control valve for crane 81 Accelerator cylinder 82 Switching control valve for outrigger 83 Switching control valve for slewing 84 Switching control valve for boom extension and retraction 85 Switching control valve for winch 86 Switching control valve for boom heaving 87 Horizontal Outrigger Cylinder Changeover Valve 88 Vertical Outrigger Cylinder Changeover Valve 90 Load Detection Unit 92 Bent Boom Angle Detection Unit 160 Controller 161 Receiver 162 Remote Control Device 180 Main Relief Valve (Unload Valve) 181 Solenoid for Unload Valve Operation SB Stop Valve CB Check Valve

Claims

1. A hydraulic equipment control device for controlling the operation of a hoisting boom that is attached to a base of a work machine so as to be able to be raised and lowered, and the operation of a folding boom that is attached to a tip of the hoisting boom so as to be able to be raised and lowered, and whose posture changes in response to a change in posture of the hoisting boom, The hoisting boom is displaced by extending or retracting the first hydraulic cylinder to change the posture of the folding boom, The folding boom is displaced by extending or contracting a second hydraulic cylinder, which is a hydraulic cylinder separate from the first hydraulic cylinder and has the same pressure oil supply source as the first hydraulic cylinder; a hydraulic control unit for controlling pressure oil supplied to the first hydraulic cylinder and the second hydraulic cylinder, the first hydraulic cylinder is a cylinder whose internal pressure decreases over time, The hydraulic control unit is a hydraulic equipment control device that transitions to an automatic pressurization mode in which pressurized oil is automatically supplied only to the first hydraulic cylinder to restore the internal pressure of the first hydraulic cylinder, which has decreased over time, when an automatic pressurization condition is satisfied when the operator is not operating the folding boom during a work mode in which pressurized oil is supplied to the second hydraulic cylinder in response to operation of the folding boom by the operator and which automatically changes the destination of the pressurized oil.

2. 2. A hydraulic equipment control device according to claim 1, further comprising a stopper member that restricts displacement of the hoisting boom in a direction in which the hoisting boom is displaced by extending the first hydraulic cylinder.

3. 3. The hydraulic equipment control device according to claim 1, wherein the automatic pressurization condition includes a condition that is satisfied when a load applied to the folding boom is equal to or smaller than a preset load.

4. 4. The hydraulic equipment control device according to claim 1, wherein the hydraulic control unit stops the supply of pressurized oil to the first hydraulic cylinder in the automatic pressurizing mode when it detects a raising operation of the folding boom while the automatic pressurizing mode is being performed.

5. 5. A hydraulic equipment control device according to claim 1, wherein the automatic pressurization condition includes a condition that is met when a hoisting angle of the hoisting boom is equal to or greater than a preset angle and an engine that is a drive source of a pressure oil supply device that supplies the pressure oil is stopped, and then the engine starts and a power take-off is activated.

6. 6. The hydraulic equipment control device according to claim 5, wherein the automatic pressurization condition includes a condition that is established when the engine that has been stopped is started by remote control by the operator using a remote control device.

7. 7. The hydraulic equipment control device according to claim 1, wherein the automatic pressurization condition includes a condition that is established when a preset first time has elapsed since the mode was changed to the work mode.

8. 8. The hydraulic equipment control device according to claim 1, wherein the automatic pressurization condition includes a condition that is met when a preset second time has elapsed since a previous transition to the automatic pressurization mode.

9. 9. The hydraulic equipment control device according to claim 1, wherein the automatic pressurization condition includes a condition that is met when a period of time during which no operation is performed by the operator while the work mode is being carried out continues for a preset third period of time.

10. a stop valve that opens or closes an oil passage between a pressure oil supply source that supplies pressure oil to the first hydraulic cylinder and the first hydraulic cylinder, and a check valve that is arranged in parallel with the stop valve and prevents a backflow of the pressure oil from the first hydraulic cylinder to the pressure oil supply source, 10. The hydraulic equipment control device according to claim 1, wherein the hydraulic control unit closes the oil passage by the stop valve after displacing the hoisting boom.

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