JP5891162B2 - crane - Google Patents

Description

  The present invention relates to a crane having a swing lever.

  A crane is known in which a swing lever (strut) is attached to the tip of a tower boom so as to be pivotable in the front-rear direction, and the jib boom is raised and lowered by the swing lever. In such a crane, when the swing lever is raised beyond a certain angle during assembly / disassembly / extension-type standing work, the backward tilting moment increases and the swing lever may fall backward.

  In Patent Document 1, a back stop is provided on the back side of the swing lever in order to limit the backward rotation of the swing lever, and a first back stop receiver that receives the back stop at the time of crane operation at the tip of the tower boom. A crane provided with a second backstop receiver that receives a backstop during assembly and disassembly is described.

Japanese Patent No. 4321224

  However, the technique described in Patent Document 1 cannot prevent the phenomenon that the swing lever tilts backward due to an increase in the backward tilting moment, that is, the occurrence of backward swing of the swing lever. For this reason, since it is necessary for the driver to perform an operation with care so that the swing lever does not fall backward, there is a problem that the burden on the driver is large.

The invention according to claim 1 includes a first boom whose base end is pivotally supported by the crane body, a second boom pivotally supported by the distal end of the first boom, a first boom hoisting device for hoisting the boom, is rotatably supported on the distal end of the first boom, second boom and linked scan Ingureba over the second pendant rope, third pendant rope and a swing lever A second boom hoisting winch wound with a second boom hoisting rope wound around the second boom hoisting winch, and winding the second boom hoisting rope with the second boom hoisting winch; or by feeding, by rotating the swing lever, a tension detecting means for detecting a second boom hoisting device for hoisting the second boom, the tension of the second boom pivoting rope swing lever A posture detecting means for detecting the posture of the swing lever immediately before the backward tilting moment about the pivoting fulcrum of the swing lever is larger than the forward tilting moment about the pivoting fulcrum of the swing lever, and the second boom detected by the tension detecting means. The condition that the tension of the hoisting rope is less than the tension when the second pendant rope is tensioned, which is set in advance to determine whether the swing lever is in a state in which the swinging of the swing lever can occur, and the posture When the condition for detecting the posture of the swing lever immediately before the backward tilting moment becomes larger than the forward tilting moment is established by the detecting means, the standing boom and the tilting motion by the first boom lifting device, and the second boom It is a crane characterized by having an operation prohibition control means for prohibiting a standing motion by the hoisting device.
According to a second aspect of the present invention, in the crane according to the first aspect, the posture detecting means includes a relative angle detecting means for detecting that the relative angle between the first boom and the swing lever is equal to or greater than a predetermined angle, And a posture determination means for determining that the posture of the swing lever immediately before the backward tilt moment becomes larger than the forward tilt moment is detected.
According to a third aspect of the present invention, in the crane according to the second aspect, the relative angle detecting means includes a first boom-to-ground angle detecting means for detecting the ground angle of the first boom, and a swing for detecting the ground angle of the swing lever. A lever-to-ground angle detection unit and a calculation unit that calculates a relative angle between the first boom and the swing lever based on the ground angle of the first boom and the ground angle of the swing lever are configured. .
According to a fourth aspect of the present invention, in the crane according to the first aspect, the posture detection means includes a swing lever ground angle detection means for detecting a ground angle of the swing lever, and a ground angle of the swing lever is a predetermined angle or more. And posture determination means for determining that the posture of the swing lever immediately before the backward tilt moment becomes larger than the forward tilt moment is detected.

  According to the present invention, it is possible to prevent the swing lever from turning backward, so that it is possible to reduce driver fatigue and improve work efficiency.

The side view which shows the external appearance of the crane which concerns on embodiment of this invention. The figure which shows an example of a structure of the crane which concerns on embodiment of this invention. The flowchart which showed the operation | movement of the winch control performed by the winch control program which concerns on embodiment of this invention. The figure which shows the initial stage attitude | position in expansion | extension-type standing work. The figure which shows the attitude | position which raised the tower about 20 degree | times in the expansion | extension-type standing work. The figure which shows the attitude | position just before cut | disconnecting the front-end | tip of a jib in expansion | extension-type standing work. The figure which shows the attitude | position after cutting off the front-end | tip of a jib in expansion | extension-type standing work. The figure which shows the normal working attitude | position after completion | finish of expansion | extension-type standing work. The figure which shows the disassembly and assembly work of a jib.

Hereinafter, an embodiment of a crane according to the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing an appearance of a crane 100 according to an embodiment of the present invention. The crane 100 includes a traveling body 101, a revolving body 103 that is turnably provided on the traveling body 101 via a turning wheel, and a tower boom 104 (a base end portion of which is pivotally supported by the revolving body 103). Hereinafter, it is simply referred to as a tower), and a jib boom 108 (hereinafter simply referred to as a jib) pivotally supported at the tip of the tower 104 is provided. A driver's cab 107 is provided at the front portion of the swing body 103, and a counterweight 109 is attached to the rear portion of the swing body 103.

  The revolving body 103 is equipped with a hook hoisting drum 105 that is a winch drum for hoisting a hook, a tower hoisting drum 106 that is a winch drum for hoisting the tower, and a jib hoisting drum 102 that is a winch drum for hoisting the jib. ing.

  A hoisting rope 151 is wound around the hook hoisting drum 105, and the hoisting rope 151 is connected to the hook 110 via the top of the tower 104 and the tip of the jib 108. When the hook hoisting drum 105 is driven, the hoisting rope 151 is wound or unwound to move the hook 110 up and down.

  One end of the first pendant rope 161 is connected to the tip of the tower 104, and the other end of the first pendant rope 161 is connected to the bridle device 162. The tower hoisting rope 163 is wound around the tower hoisting drum 106 through a plurality of times between the bridle device 162 and the hanger 165 via the top of the A frame 164. When the tower hoisting drum 106 is driven, the tower hoisting rope 163 is wound or fed out, whereby the distance between the hanger 165 and the bridle device 162 is changed, and the tower 104 is hoisted.

  A swing lever 140 is pivotally supported at the tip of the tower 104 so as to be rotatable. The swing lever 140 is formed in a triangular shape by a first support column 140a, a second support column 140b, and a connecting member 140c that connects the first support column 140a and the second support column 140b.

  One apex angle portion of the swing lever 140, that is, the distal end portion of the first column 140 a is connected to the distal end portion of the jib 108 by the second pendant rope 141. The other apex portion of the swing lever 140, that is, the tip of the second support 140b is connected to the jib hoisting rope 143 via the third pendant rope 142 and the bridle device 144. The jib hoisting rope 143 is wound around the jib hoisting drum 102 by being wound around the bridle device 144 and the guide roller 145 a plurality of times. When the jib hoisting drum 102 is driven, the jib hoisting rope 143 is wound or fed out, and the swing lever 140 is rotated in the front-rear direction, whereby the jib 108 is hoisted.

  FIG. 2 is a diagram illustrating an example of the configuration of the crane 100 according to the embodiment of the present invention. FIG. 2 shows a control system for controlling the rotation of the jib hoisting drum 102 and the tower hoisting drum 106 and a hydraulic circuit for driving the hydraulic motors 132J and 132B for hoisting the jib 108 and the tower 104. In FIG. 2, a hydraulic circuit for driving a hook winding hydraulic motor, a turning hydraulic motor, and the like is omitted.

  As shown in FIG. 2, the crane 100 includes a main pump 131, a pilot pump 132, a jib hoisting hydraulic system 130J for hoisting the jib 108, and a tower hoisting hydraulic system 130B for hoisting the tower 104. It has. The main pump 131 and the pilot pump 132 are hydraulic pumps that are driven by a prime mover (not shown) such as an engine.

  The jib hoisting hydraulic system 130J includes a hydraulic motor 132J, a jib hoisting drum 102, a control valve 133J, an operation lever 134J, and an electromagnetic switching valve 135. The tower hoisting hydraulic system 130B includes a hydraulic motor 132B, a tower hoisting drum 106, a control valve 133B, an operation lever 134B, an electromagnetic switching valve 136, and an electromagnetic switching valve 137.

  A hydraulic motor 132J of the jib hoisting hydraulic system 130J is discharged from the main pump 131 and is driven to rotate by pressure oil whose flow rate and direction are controlled by the control valve 133J. The jib hoisting drum 102 is rotated by driving of the hydraulic motor 132J. When the control valve 133J operates to the position (A) side, the hydraulic motor 132J rotates in the winding direction, and when the control valve 133J operates to the position (B) side, the hydraulic motor 132J rotates in the winding direction.

  The hydraulic motor 132B of the tower hoisting hydraulic system 130B is discharged from the main pump 131 and is driven to rotate by pressure oil whose flow rate and direction are controlled by the control valve 133B. The tower hoisting drum 106 is rotated by driving the hydraulic motor 132B. When the control valve 133B operates to the position (A) side, the hydraulic motor 132B rotates in the winding direction, and when the control valve 133B operates to the position (B) side, the hydraulic motor 132B rotates in the winding direction.

  An operation lever 134J for operating the jib 108 is a pilot-type hydraulic operation lever provided with a pilot valve 138J that outputs a pilot pressure corresponding to a standing (raising) command or a lying (lowering) command of the jib 108. Operated to drive valve 133J. The pilot valve 138J generates a secondary pressure corresponding to the operation amount of the operation lever 134J. The pilot valve 138J is supplied with pressure oil from the pilot pump 132, and the pilot secondary pressure corresponding to the operation of the operation lever 134J is input to the pilot portion of the control valve 133J.

  In the jib hoisting hydraulic system 130J, an electromagnetic switching valve 135 is interposed in a pipe line connecting the pilot valve 138J and the winding pilot portion of the control valve 133J.

  When the operation lever 134J is operated to the jib up side by the driver while the electromagnetic switching valve 135 is switched to the position (C), the pilot pressure acts on the hoisting pilot portion of the control valve 133J, and the control valve 133J Moves to the position (A) side, and the jib hoisting drum 102 is rotated in the winding direction. By turning the jib hoisting drum 102 in the winding direction, the jib hoisting rope 143 is taken up, and the jib 108 is rotated rearward.

  When the driver operates the operation lever 134J to the jib lowering side, the pilot pressure acts on the lower pilot portion of the control valve 133J, and the control valve 133J operates to the position (B) side, and the jib hoisting drum 102 is operated. Is rotated in the lowering direction. By turning the jib hoisting drum 102 in the winding down direction, the jib hoisting rope 143 is fed out, and the jib 108 turns forward.

  An operation lever 134B for operating the tower 104 is a pilot-type hydraulic operation lever provided with a pilot valve 138B that outputs a pilot pressure corresponding to a standing (raising) command or a lying (lowering) command of the tower 104. Operated to drive valve 133B. The pilot valve 138B generates a secondary pressure corresponding to the operation amount of the operation lever 134B. Pressure oil is supplied to the pilot valve 138B from the pilot pump 132, and a pilot secondary pressure corresponding to the operation of the operation lever 134B is input to the pilot portion of the control valve 133B.

  In the tower hoisting hydraulic system 130B, an electromagnetic switching valve 136 is interposed in a pipe line connecting the pilot valve 138B and the upper pilot part of the control valve 133B, and the lower pilot of the pilot valve 138B and the control valve 133B. An electromagnetic switching valve 137 is interposed in a pipe line connecting the sections.

  When the operation lever 134B is operated to the tower raising side by the driver while the electromagnetic switching valve 136 is switched to the position (C), the pilot pressure acts on the hoisting pilot portion of the control valve 133B, and the control valve 133B. Moves to the position (A) side, and the tower hoisting drum 106 is rotated in the winding direction. As the tower hoisting drum 106 rotates in the winding direction, the tower hoisting rope 163 is taken up, and the tower 104 rotates rearward.

  When the operation lever 134B is operated to the tower lowering side by the driver when the electromagnetic switching valve 137 is switched to the position (C), the pilot pressure acts on the lowering pilot portion of the control valve 133B, and the control valve 133B moves to the position (B) side, and the tower undulating drum 106 is rotated in the winding down direction. The tower hoisting rope 163 is fed out by turning the tower hoisting drum 106 in the winding direction, and the tower 104 turns forward.

  When the control signal (excitation current) from the controller 120 is input, the electromagnetic switching valve 135 of the jib hoisting hydraulic system 130J is switched to the position (D). In this state, pilot pressure oil is not supplied to the hoisting pilot portion of the control valve 133J even if the operation lever 134J is operated to the hoisting side. That is, the electromagnetic switching valve 135 functions as a stop valve.

  The electromagnetic switching valve 135 is switched to the position (C) when no control signal (excitation current) is input, that is, when the excitation current I = 0. In this state, the secondary pressure from the pilot valve 138J corresponding to the lever operation amount of the operating lever 134J acts on the hoisting pilot portion of the control valve 133J without being reduced. That is, the electromagnetic switching valve 135 functions as an open valve.

  When the control signal (excitation current) from the controller 120 is input, the electromagnetic switching valves 136 and 137 of the tower hoisting hydraulic system 130B are switched to the position (D), respectively. In this state, even if the operation lever 134B is operated to the upper / lower side, the pilot pressure oil is not supplied to the upper / lower pilot part of the control valve 133B. That is, the electromagnetic switching valves 136 and 137 each function as a stop valve.

  The electromagnetic switching valves 136 and 137 are switched to the position (C) when the control signal (excitation current) is not input, that is, when the excitation current I = 0. In this state, the secondary pressure from the pilot valve 138B corresponding to the lever operation amount of the operation lever 134B acts on the winding / lowering pilot portion of the control valve 133B without being reduced. That is, the electromagnetic switching valves 136 and 137 each function as an open valve.

  The controller 120 shown in FIG. 2 includes an arithmetic processing unit having a CPU, a ROM and a RAM that are storage devices, and other peripheral circuits. The controller 120 controls the entire system of the crane 100 and switches the electromagnetic switching valves 135, 136, and 137 to the position (D) when a predetermined condition described later is satisfied, and the winding direction of the hydraulic motor 132J. And the rotation of the hydraulic motor 132B in the winding and lowering directions are prohibited.

  As shown in FIG. 2, a tower-to-ground angle sensor 171, a swing lever-to-ground angle sensor 172, a tension sensor 173, and a display device 122 that displays a predetermined display screen are connected to the controller 120. The tower ground angle sensor 171 is provided in the vicinity of the rotation fulcrum of the tower 104 and detects the ground angle θb with respect to the ground (horizontal plane) of the tower 104. The swing lever ground angle sensor 172 is provided near the rotation fulcrum of the swing lever 140 and detects the ground angle of the swing lever 140 with respect to the ground (horizontal plane). The tension sensor 173 is a load cell that detects the tension of the jib hoisting rope 143.

  The controller 120 receives the ground angle signal detected by the tower ground angle sensor 171 and the swing lever ground angle sensor 172, and the tension signal detected by the tension sensor 173, and performs electromagnetic switching based on these signals. Control signals are output to the valves 135, 136 and 137 to control their operations.

  The controller 120 controls the relative angle calculation unit 120a and the posture determination unit 120b in order to control prohibition / permission of driving of the hydraulic motors 132J and 132B according to the raising operation of the operation lever 134J and the raising / lowering operation of the operation lever 134B. And a stop condition determination unit 120c, a work determination unit 120d, and a valve control unit 120e.

  The relative angle calculation unit 120a takes the difference between the ground angle θs of the swing lever 140 detected by the swing lever ground angle sensor 172 and the ground angle θb of the tower 104 detected by the tower ground angle sensor 171 to obtain the tower 104 And the relative angle θr between the swing lever 140 and the swing lever 140 are calculated (θr = θs−θb). The relative angle θr is an angle at which the swing lever 140 is tilted backward with respect to the tower 104, and the relative angle θr increases as the ground angle θs of the swing lever 140 increases with respect to the ground angle θb of the tower 104. .

  In the posture determination unit 120b, when the relative angle θr is equal to or greater than the predetermined angle θt, the backward tilt moment Mb around the rotation fulcrum of the swing lever 140 is larger than the forward tilt moment Mf around the rotation fulcrum of the swing lever 140. It is determined that the previous posture of the swing lever 140 has been detected. The predetermined angle θt has a posture in which the forward tilting moment Mf is slightly larger than the backward tilting moment Mb with an allowance from an angle at which the backward tilting moment Mb and the forward tilting moment Mf are substantially equal. The relative angle of time is adopted. The predetermined angle θt is stored in advance in the storage device as a threshold value.

  A method for determining the predetermined angle θt as a threshold will be described. The phenomenon in which the swing lever 140 falls backward (hereinafter referred to as “backward turn”) refers to the tensile force of the jib hoisting rope 143 against the forward tilting moment Mf due to the weight of the swing lever 140 in the process of raising the tower 104. Occurs when the backward tilting moment Mb that increases due to the above increases.

  The relative angle θr at which the backward turn occurs varies depending on the length of the tower 104 and the length of the jib 108, and also varies depending on the posture of the crane 100. For this reason, depending on the type of the tower 104 and the jib 108 attached to the crane 100 and all the combinations of the tower 104 and the jib 108, the backward leaning occurs in the posture immediately before the second pendant rope 141M is tensioned. An angle smaller than the relative angle θr is determined as the threshold θt. The plurality of threshold values θt determined in this way are stored in advance in the storage device as a threshold value table. The type of the tower 104 and the type of the jib 108 can be selected by a selection switch (not shown). When the operator selects the type of the tower 104 and the type of the jib 108 at the time of assembly setup, the controller 120 , The threshold value table corresponding to the specification of the selected crane 100 is set with reference to the threshold value table.

  The work determination unit 120d shown in FIG. 2 determines whether or not the tension T of the jib hoisting rope 143 detected by the tension sensor 173 is less than the predetermined tension Tt, and if the tension T is less than the predetermined tension Tt. Then, it is determined that the swing lever 140 is in a working state in which the backward turning of the swing lever 140 can occur. The predetermined tension Tt is a tension value when the weight of the jib 108 acts on the second pendant rope 141 and the second pendant rope 141 is in tension, and is stored in the storage device in advance.

  The stop condition determination unit 120c automatically detects when the tension T of the jib hoisting rope 143 detected by the tension sensor 173 is less than the predetermined tension Tt and the relative angle θr calculated by the relative angle calculation unit 120a is greater than or equal to the predetermined angle θt. It is determined that the stop condition is satisfied. The stop condition determination unit 120c determines that the automatic stop condition is not satisfied when the tension is equal to or greater than the predetermined tension Tt or when the relative angle θr is less than the predetermined angle θt.

  The valve control unit 120e prohibits or permits driving of the hydraulic motor 132J in the lowering direction and driving of the hydraulic motor 132B in the winding / lowering direction according to the following conditions. In other words, the valve control unit 120e switches the positions of the electromagnetic switching valves 135, 136, and 137 according to the following conditions.

(1) The valve control unit 120e is automatically stopped by the stop condition determining unit 120c when rotation in the winding direction of the jib hoisting drum 102 and rotation in the hoisting / lowering direction of the tower hoisting drum 106 are permitted. When it is determined that is established, a control signal (excitation current) is output to each of the electromagnetic switching valves 135, 136, 137, and each of the electromagnetic switching valves 135, 136, 137 is switched to the position (D). That is, when the automatic stop condition is satisfied, the valve control unit 120e prohibits the rotation of the jib hoisting drum 102 in the winding direction even when the raising command is output by the operation lever 134J, and the raising / lowering command is issued by the operation lever 134B. Even if it is output, rotation of the tower hoisting drum 106 in the winding / lowering direction is prohibited.

(2) The valve control unit 120e is automatically operated by the stop condition determination unit 120c when rotation of the jib hoisting drum 102 in the winding direction and rotation of the tower hoisting drum 106 in the winding / lowering direction are prohibited. If it is determined that the stop condition is not satisfied, the control signal (excitation current) supplied to each of the electromagnetic switching valves 135, 136, 137 is set to 0, and each of the electromagnetic switching valves 135, 136, 137 is moved to the position ( Switch to C). That is, when the automatic stop condition is not satisfied, the valve control unit 120e rotates the jib hoisting drum 102 in the winding direction according to the raising command of the operation lever 134J and the tower according to the raising / lowering command of the operation lever 134B. The rotation of the hoisting drum 106 in the winding / lowering direction is permitted.

Hereinafter, the process by the winch control program for preventing the swing lever 140 from turning backward will be described with reference to the flowchart shown in FIG.
FIG. 3 is a flowchart showing an operation of winch control executed by the winch control program according to the embodiment of the present invention. When an engine switch (not shown) is turned on, a program for performing the processing shown in FIG. Although not shown, when the program is activated, the controller 120 starts acquiring signals from the tower-to-ground angle sensor 171, the swing lever-to-ground angle sensor 172, and the tension sensor 173.

  As shown in FIG. 3, in step S100, the controller 120 receives the tension sensor signal detected by the tension sensor 173, and determines whether or not the tension T of the jib hoisting rope 143 is less than a predetermined tension Tt. If an affirmative determination is made in step S100, the process proceeds to step S110, and if a negative determination is made, the process proceeds to step S120.

  In step S110, the controller 120 calculates the difference between the ground angle θs of the swing lever 140 detected by the swing lever ground angle sensor 172 and the ground angle θb of the tower 104 detected by the tower ground angle sensor 171, and The relative angle θr between 104 and the swing lever 140 is calculated (θr = θs−θb), and the process proceeds to step S115.

  In step S115, the controller 120 determines whether or not the relative angle θr is equal to or greater than the predetermined angle θt. If a positive determination is made in step S115, the process proceeds to step S140, and if a negative determination is made, the process proceeds to step S120.

  As described above, if it is determined in step S100 that the tension T is greater than or equal to the predetermined tension Tt, or if it is determined in step S115 that the relative angle θr is less than the predetermined angle θt, the process proceeds to step S120. In step S120, the controller 120 demagnetizes the solenoid by setting the control signal (excitation current) supplied to each of the electromagnetic switching valves 135, 136, and 137 to 0, and proceeds to step S130. Thereby, the electromagnetic switching valves 135, 136, and 137 are respectively switched to the position (C). As a result, the jib 108 can be raised (standing up) according to the raising operation of the operating lever 134J, and the tower 104 is raised (standing up) according to the raising / lowering operation of the operating lever 134B. / Possible to move down (fall down). Hereinafter, this state is also referred to as an operation permission state.

  In the next step S <b> 130, the controller 120 executes a process of displaying a warning screen on the display device 122 in step S <b> 150 described later, and if the warning screen is displayed on the display device 122, the warning screen of the display device 122 is displayed. Execute the process of hiding and return.

  In step S115, when it is determined that the relative angle θr is equal to or larger than the predetermined angle θt and the process proceeds to step S140, the controller 120 outputs a control signal (excitation current) to each of the electromagnetic switching valves 135, 136, and 137 to output a solenoid. Is advanced to step S150. Thereby, the electromagnetic switching valves 135, 136, and 137 are respectively switched to the position (D). As a result, the jib 108 cannot be raised, that is, the swing lever 140 cannot be rotated backward via the jib hoisting rope 143. Furthermore, the tower 104 cannot move up and down. Hereinafter, this state is also referred to as an operation prohibited state. Therefore, if the operation lever 134J is operated to the raising side, the backward pivoting operation of the swing lever 140 is stopped, and if the operation lever 134B is operated to the raising / lowering side, the tower 104 is raised and lowered. Stop.

  In step S150, the controller 120 displays a warning screen on the display device 122 installed in the cab 107, and returns.

  In the above processing, the work determination unit 120d determines that the swing lever 140 is in a work state in which the swinging of the swing lever 140 may occur when the tension T of the jib hoisting rope 143 is less than the predetermined tension Tt (step S100). . When the relative angle θr calculated by the relative angle calculation unit 120a is equal to or greater than the predetermined angle θt (step S115), the posture determination unit 120b determines that the backward tilt moment Mb around the rotation fulcrum of the swing lever 140 is the rotation of the swing lever 140. It is determined that the posture of the swing lever 140 immediately before it becomes larger than the forward tilting moment Mf around the fulcrum is detected. The stop condition determination unit 120c is configured such that the tension of the jib hoisting rope 143 detected by the tension sensor 173 is less than the predetermined tension Tt (step S100), and the relative angle θr calculated by the relative angle calculation unit 120a is greater than or equal to the predetermined angle θt. (Step S115), it is determined that the automatic stop condition is satisfied. When it is determined that the automatic stop condition is satisfied, the valve control unit 120e switches the electromagnetic switching valves 135, 136, and 137 to the position (D) and sets the operation prohibited state (step S140). When it is determined that the automatic stop condition is not satisfied, the valve control unit 120e switches the electromagnetic switching valves 135, 136, and 137 to the position (C), respectively, and sets the operation permitted state (step S120).

  The operation of the electromagnetic switching valves 135, 136, and 137 by the winch control program is summarized as follows in accordance with the standing work procedure of the crane 100 with reference to FIGS. In the present embodiment, the tower 104 and the jib 108 of the crane 100 are removed from the crane body and disassembled during transportation. After arrival at the work site, as shown in FIG. 4, the tower 104 and the jib 108 are assembled, the second pendant rope 141 is attached between the jib 108 and the swing lever 140, and the third pendant rope 142 is connected to the swing lever 140. And a bridle device 144 (see FIG. 1), and a first pendant rope 161 (see FIG. 1) is attached between the tower 104 and the bridle device 162 (see FIG. 1).

  Thereafter, the driver performs a standing work operation in order to place the crane 100 in the normal working posture. In the present embodiment, the tower 104 is gradually raised from a state where the tower 104 and the jib 108 are extended in the front-rear direction. Hereinafter, such a standing work is referred to as an extension-type standing work. FIG. 4 is a diagram showing an initial posture in the extension-type standing work. A wheel 190 is attached to the tip of the jib 108. The driver operates the operation lever 134J and the operation lever 134B to raise the tower 104 while keeping the wheel 190 attached to the tip of the jib 108 in contact with the ground.

  FIG. 5 is a view showing a posture in which the tower 104 is raised about 20 degrees in the extension-type standing work, and FIG. 6 is a posture in which the tower 104 is further raised in the extension-type standing work, and the tip of the jib 108 is grounded. It is a figure which shows the attitude | position just before cutting. As shown in FIG. 5, the driver operates the operation lever 134J and the operation lever 134B to gradually erect the tower 104, and as shown in FIG. .

  When the second pendant rope 141 is in a bent state during the transition from the initial posture shown in FIG. 4 to the posture immediately before the ground cutting shown in FIG. 6, there is a possibility that backward turning may occur. In this working state, the jib hoisting rope 143 is not subjected to the own weight of the jib 108 via the swing lever 140, and the tension sensor 173 detects a smaller tension than that during normal work (steps S100 → S110). ). At this time, a forward tilting moment Mf due to the weight of the swing lever 140 and a backward tilting moment Mb due to the tensile force of the jib hoisting rope 143 act on the swing lever 140.

  As shown in FIG. 5, when the tension T of the jib hoisting rope 143 is less than the predetermined tension Tt, that is, in a state in which a backward turn can occur, the relative angle θr between the swing lever 140 and the tower 104 is a predetermined angle. When it becomes equal to or greater than θt (step S115), the electromagnetic switching valves 135, 136, and 137 are respectively switched to the position (D) (step S140), and the operation is prohibited. That is, the supply of the pilot pressure to the upper pilot part of the control valve 133J is blocked by the electromagnetic switching valve 135, and the supply of the pilot pressure to the upper / lower pilot part of the control valve 133B is performed by the electromagnetic switching valves 136 and 137, respectively. Is blocked by.

  For example, if the automatic stop condition is satisfied while the driver is operating both the operation lever 134J and the operation lever 134B to the up side, the control valve 133J is positioned even if the operation levers 134J and 134B are operated. A) is switched to position (N), and control valve 133B is switched from position (A) to position (N). For this reason, the rotations of the hydraulic motors 132J and 132B, the jib hoisting drum 102, and the tower hoisting drum 106 are stopped, and the swing lever 140 and the tower 104 are stopped. As a result, it is possible to prevent the swing lever 140 from turning backward.

  On the display device 122, a warning screen is displayed (step S150), and it is notified that the swing lever 140 has stopped automatically when the swing lever 140 is in a state immediately before the backward swing occurs.

  After the operations of the tower 104 and the jib 108 are automatically stopped, when the driver lowers the operation lever 134J, the swing lever 140 rotates forward, and the relative angle θr decreases. When the relative angle θr becomes less than the predetermined angle θt (step S115), the electromagnetic switching valves 135, 136, and 137 are respectively switched to the position (C) (step S120), and the operation is permitted. That is, the pilot pressure can be supplied to the hoisting pilot portion of the control valve 133J, and the pilot pressure can be supplied to the hoisting / lowering pilot portion of the control valve 133B.

  In the present embodiment, after the operations of the tower 104 and the jib 108 are automatically stopped, the tower 104 is not allowed to fall down in response to the lowering operation of the operation lever 134B. For this reason, after the automatic stop, only the inclining operation of the tower 104 is performed, and thus the swing lever 140 is prevented from turning backward due to the swing lever 140 rotating backward.

  When the operation permission state is restored, the warning screen of the display device 122 is not displayed (step S130), so that the driver can confirm that the operation levers 134J and 134B can be operated again.

  When the driver operates the operation levers 134J and 134B and proceeds with the standing operation, the weight of the jib 108 acts on the second pendant rope 141 as shown in FIG. get nervous. The weight of the jib 108 is transmitted to the jib hoisting rope 143 via the second pendant rope 141 and the swing lever 140, and the tension T of the jib hoisting rope 143 becomes equal to or higher than the predetermined tension Tt (steps S100 → S120). At this time, since the forward tilting moment Mf due to the weight of the jib 108 acts on the swing lever 140, there is no possibility of occurrence of backward turning.

  FIG. 7 is a view showing a posture after the tip of the jib 108 is ground in the extension-type standing work. As shown in FIG. 7, the driver raises the tower 104 from the posture (see FIG. 6) immediately before the ground cutting, and grounds the jib 108.

  FIG. 8 is a diagram illustrating a normal working posture after the extension-type standing work is completed. As shown in FIG. 8, after the driver cuts the jib 108, the driver raises the tower 104 to the maximum ground angle and then raises the jib 108 to form the normal working posture.

According to the embodiment described above, the following operational effects can be obtained.
(1) The condition that the tension T of the jib hoisting rope 143 detected by the tension sensor 173 is less than the predetermined tension Tt, and the condition that the relative angle θr between the tower 104 and the swing lever 140 is greater than or equal to the predetermined angle θt, that is, the rearward tilt When the condition for detecting the posture of the swing lever immediately before the moment Mb becomes greater than the forward tilting moment Mf is satisfied, it is determined that the automatic stop condition is satisfied. When it is determined that the automatic stop condition is satisfied, the rotation of the tower hoisting drum 106 in the winding / lowering direction and the rotation of the jib hoisting drum 102 in the hoisting direction are prohibited.

  Thereby, it is possible to prevent the swing lever 140 from being turned backward during the extension-type standing work. Therefore, the driver does not need to perform an operation while paying attention so that the swing lever 140 does not turn backward. That is, according to the present embodiment, the burden on the driver can be reduced, and the work efficiency can be improved. Moreover, even a driver with little experience can easily perform the crane 100 standing work.

(2) In a crane that does not have a configuration for preventing the occurrence of backward turning, when the backward turning of the swing lever 140 occurs during the standing work, the swing lever 140 is moved backward until the second pendant rope 141 is tensioned. The connection part of the second pendant rope 141 may be damaged. On the other hand, according to the present embodiment, it is possible to prevent the back turn from occurring, so that the connection portion of the second pendant rope 141 can be prevented from being damaged.

(3) When the back stop mechanism is provided at the tip of the tower as in the technique described in Patent Document 1, the weight increases. On the other hand, according to the present embodiment, the weight of the tower 104 can be reduced as compared with the technique described in Patent Document 1. As a result, the lifting performance can be improved.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
[Modification]
(1) In the above-described embodiment, the description has been given of the point of preventing the rearward tilting at the time of the extension-type standing work. However, the present invention is not limited to this, and the swing lever 140 of the jib 108 is disassembled and assembled. It is possible to prevent the occurrence of backward turning. As shown in FIG. 9, when the jib 108 is assembled and disassembled, the swing lever 140 is raised to a predetermined height, and when the tower 104 is slightly raised, the backward tilting moment of the swing lever 140 is increased, so that rearward tilt occurs. There is a risk. However, when the relative angle θr is equal to or greater than θt, the swinging operation of the swing lever 140 and the tower 104 is automatically stopped and the occurrence of backward turning is prevented, so that the swing lever 140 and the tower 104 are contacted and damaged. There is no fear of doing.

(2) In the above-described embodiment, the example in which the automatic stop condition is satisfied when the tension T of the jib hoisting rope 143 is less than the predetermined tension Tt and the relative angle θr is equal to or greater than the predetermined angle θt has been described. However, the present invention is not limited to this. It may be determined that the automatic stop condition is satisfied when the tension T of the jib hoisting rope 143 is less than the predetermined tension Tt and the ground angle θs of the swing lever 140 is equal to or larger than the predetermined angle θst. Note that the maximum ground angle θs that the swing lever 140 can take before the second pendant rope 141 is tensioned in the standing work posture of each configuration of the crane 100, that is, the ground angle θs immediately before the rearward turn occurs. It is adopted as each threshold value θst. As in the above-described embodiment, it is preferable to compare the relative angle θr and the predetermined angle θt because the automatic stop condition is established at an earlier stage.

(3) In the above-described embodiment, the example in which the present invention is applied to a tower crane including the tower boom 104 and the jib boom 108 has been described. However, the present invention is not limited to this. For example, the present invention may be applied to a telescopic boom and a telescopic crane having a jib boom at the tip of the telescopic boom.

(4) In the above-described embodiment, the rotation of the hydraulic motors 132B, 132J is limited using the electromagnetic switching valves 135, 136, 137, but instead of the electromagnetic switching valves 135, 136, 137, the electromagnetic proportional A valve may be employed.

(5) The present invention is not limited to the case where a load cell is used as the tension sensor 173.

  The present invention is not limited to the above-described embodiment, and can be freely changed and improved without departing from the gist of the invention.

100 crane, 101 traveling body, 102 jib hoisting drum, 103 revolving body, 104 tower (tower boom), 105 hook hoisting drum, 106 tower hoisting drum, 107 cab, 108 jib (jib boom), 109 counterweight, 110 hook , 120 controller, 120a relative angle calculation unit, 120b attitude determination unit, 120c stop condition determination unit, 120d work determination unit, 120e valve control unit, 122 display device, 130B tower undulation hydraulic system, 130J jib undulation hydraulic system, 131 Main pump, 132 pilot pump, 132B hydraulic motor, 132J hydraulic motor, 133B control valve, 133J control valve, 134B operation lever, 134J operation lever, 135 electromagnetic switching valve, 136 electromagnetic switching valve, 137 electromagnetic switching valve, 140 swing lever 140a First strut, 140b Second strut, 140c Connecting member, 141 Second pendant rope, 142 Third pendant rope, 143 Jib hoisting rope, 144 Bridle device, 145 Guide roller, 151 Hoisting rope, 161 First pendant rope , 162 Bridle device, 163 Tower hoisting rope, 164 A frame, 165 hanger, 171 Tower to ground angle sensor, 172 Swing lever to ground angle sensor, 173 Tension sensor, 190 wheels

Claims (4)

A first boom whose base end is pivotally supported by the crane body;
A second boom pivotally supported at the tip of the first boom;
A first boom hoisting device for hoisting the first boom;
Is rotatably supported on the distal end portion of the front Symbol first boom, the second boom and the linked scan Ingureba over the second pendant rope is connected via a third pendant rope and bridle system to the swing lever A second boom hoisting rope, and a second boom hoisting winch on which the second boom hoisting rope is wound, and the second boom hoisting winch winds up or unwinds the second boom hoisting rope. A second boom hoisting device for hoisting the second boom by rotating the swing lever;
Tension detecting means for detecting the tension of the second boom hoisting rope;
Tilting moment after about pivot point of the swing lever, a position detecting means for detecting a posture of the swing lever immediately before is larger than anteversion moment about the pivot point of the swing lever,
The second pendant rope, which is preset in order to determine whether the tension of the second boom hoisting rope detected by the tension detecting means is in a state in which the swing lever can be turned backward, a condition which is less than the tension when tense by the posture detection means, when a condition that the posture of the swing lever immediately before the backward tilting moment is larger than the forward inclination moment is detected are both satisfied A crane having an upright operation and a overturning operation by the first boom hoisting device and an operation prohibiting control means for prohibiting an upright operation by the second boom hoisting device. The crane according to claim 1,
The posture detection means includes: a relative angle detection means for detecting that a relative angle between the first boom and the swing lever is equal to or greater than a predetermined angle; and when the relative angle is equal to or greater than a predetermined angle, crane, characterized in that the attitude of the swing lever immediately before is larger than the forward inclination moment is configured to include a determining attitude determination means to have been detected. The crane according to claim 2,
The relative angle detection means includes first boom ground angle detection means for detecting the ground angle of the first boom, swing lever ground angle detection means for detecting the ground angle of the swing lever, and ground angle of the first boom. And a calculating means for calculating a relative angle between the first boom and the swing lever based on the ground angle of the swing lever. The crane according to claim 1,
The posture detection means includes a swing lever ground angle detection means for detecting a ground angle of the swing lever, and the backward tilt moment is greater than the forward tilt moment when the ground angle of the swing lever is equal to or greater than a predetermined angle. crane, characterized in that the attitude of the swing lever just before is configured to include a determining attitude determination means to have been detected.

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