JP4186822B2 - Mobile crane - Google Patents

Description

The present invention relates to a mobile crane configured mounted for derricking jib on the tip of the boom.

  In a mobile crane, when the machine becomes large, it is necessary to divide the machine body and attachment booms, jibs, and components of these hoisting devices to the work site, transport them, and assemble them at the work site. There is.

  A mobile crane is a base machine consisting of an undercarriage and an upper swing body. A boom (referred to as a tower depending on the specifications), and a jib attached to the tip of the boom so that it can be raised and lowered, basically holding the boom at a fixed angle. In this state, the jib is raised and lowered to perform the crane work.

  Some cranes work by raising and lowering both the boom and the jib, and the present invention includes this type of mobile crane.

  In such a mobile crane, a jib hoisting winch provided in a base machine (upper turning body) as a jib hoisting device for hoisting the jib, and a jib hoisting rope wound and unwound by the jib hoisting winch, A lower and upper spreader around which the jib hoisting rope is hung, a strut attached to the top of the boom so as to be pivotable in the front-rear direction around a horizontal axis, a jib guy line connecting the strut and the jib, and a strut And a strut guy line connecting the upper spreader.

  Prior to assembly, the upper spreader is placed on the upper surface of the boom proximal end for reasons such as making the jib hoisting rope easy to hang by reducing the distance from the lower spreader secured to the boom proximal end. At the time of assembly, it is pulled out to the front end side of the boom, that is, to a position where it can be connected to the strut guy line.

  Conventionally, the pulling-up force of the hook hoisting device (hook hoisting winch and the same rope) is used as a method for performing the pull-out operation of the upper spreader and the pulling-back operation at the time of disassembly without using another crane or another winch. A method of using is known (see Patent Document 1).

  In this known technique, a guide sheave dedicated to assembly and disassembly is provided at the tip of the rear member constituting the strut, and the hook hoisting rope pulled out from the hook hoisting winch is passed through the guide sheave and folded back to the boom proximal end side. After the tip is fixed to the upper spreader, the jib hoisting rope is rewound while winding the hook hoisting rope.

  Thereby, the upper spreader is levitated in the air and moved to the boom tip side, and then the hook hoisting rope is rewound to lower the spreader to the boom tip side upper surface and connected to the strut guy line.

At the time of disassembly, the upper spreader is moved to the upper surface on the boom base end side by the reverse procedure.
JP 11-292471 A

  However, according to the above known technique, a dedicated guide sheave is provided on the strut rear member for moving the upper spreader, so that the weight of the boom tip side (around the strut) becomes heavy, which is disadvantageous in terms of work ability. There was a problem that the cost was increased by adding the sheave.

  On the other hand, when performing the operation of rewinding the jib hoisting rope while rewinding the hook hoisting rope (rewinding at the time of disassembly), it is necessary to synchronize both ropes. Because this synchronization depends on the manual operation of the operator, the tension of the jib undulations and the ropes on the hook winding will become excessive due to the loss of synchronization, leading to the breakage of both ropes and damage to the structure, There was a risk that it would be too small and cause turbulence.

  In the above-mentioned known technique, even if there is a loss of synchronization, it can be absorbed by the rotational displacement of the strut. However, with this alone, the rope tension is appropriately adjusted because the rotational range of the strut is limited by the backstop. It was insufficient to keep the range.

The present invention, while maintaining a technique of moving the upper spreader by a hook hoisting rope and jib hoist rope between the boom base end and the distal end side, there is no need to provide a dedicated guide sheave movement of the upper spreader together, there is provided a mobile crane which a movement time of the tuning of the hook hoisting rope and jib hoist ropes above portion spreader can be taken accurately.

The inventions of claim 1, the boom to the base machine, jib mounted for undulations respectively on the tip of the boom, and is intended to satisfy the requirements of the following (1) to (4).

(1) The jib hoisting device for hoisting the jib is composed of a jib hoisting winch mounted on the base machine, a jib hoisting rope wound and unwound by the jib hoisting winch, and the jib hoisting rope. Lower and upper spreaders for raising and lowering the jib, a strut attached to the top of the boom so as to be pivotable in the longitudinal direction about a horizontal axis, a jib guy line connecting the strut and the jib, the strut and the upper The upper spreader is configured to be movable between the proximal end side and the distal end side along the upper surface of the boom when the crane is assembled and disassembled.

(2) A hook hoisting device that suspends and raises a suspension hook from the tip of the jib is a hook hoisting winch mounted on a base machine, and a hook that is wound and unwound by the hook hoisting winch. A hoisting rope and a hook hoisting guide sheave for guiding the hook hoisting rope from the top of the boom toward the jib tip side.

(3) The hook hoisting guide sheave is configured so that the hook hoisting rope can be folded and guided along the upper surface of the boom toward the upper spreader placed on the boom base end side during crane assembly / disassembly. It is provided on the top of

(4) Tension detecting means for detecting the tension of the jib hoisting rope and control means for regulating the operations of the jib hoisting winch and the hook hoisting winch, the control means comprising the upper spreader during crane assembly / disassembly. So that the rope tension detected by the tension detecting means during the movement is within the range of appropriate values set in advance on the high tension side and the low tension side, respectively, and the operations of the jib undulation and hook winding winches are regulated. To be configured.

According to a second aspect of the invention, in the configuration of claim 1, control means, the direction of the winch rope tension when the rope tension being detected becomes stopped more than the set value exceeding the proper value of the high-tension side is increased The operation is automatically stopped, and the winch operation in the direction in which the rope tension is reduced is automatically stopped when the operation is automatically set to a value equal to or less than the set stop value on the low tension side .

According to a third aspect of the present invention, in the configuration of the first or second aspect, the control means is configured to increase the rope tension when the detected rope tension becomes equal to or greater than a deceleration set value that exceeds an appropriate value on the high tension side. The winch operation is decelerated, and the winch operation in the direction in which the rope tension decreases when the lower tension side is less than or equal to the set deceleration value is reduced .

According to a fourth aspect of the present invention, in any one of the first to third aspects, a boom angle detecting means for detecting a boom angle is provided, and the control means is configured such that the boom angle detected by the boom angle detecting means is equal to the crane assembly. -It is comprised so that winch operation | movement may be controlled on condition that it is the angle at the time of decomposition | disassembly .

The invention of claim 5, in the construction of claims 1 to 4, which is a spreader guide means for moving the guide to and from the boom base end and the distal end side along the upper spreader boom top has been eclipsed set It is.

According to a sixth aspect of the invention, in the configuration of claim 5, as a spreader guide means, rails on the upper surface of the boom, the roller rolling on the rail in the upper spreader those were found respectively.

  According to the present invention, the hook hoisting guide sheave originally provided at the top of the boom as a part of the hook hoisting device is also used as a guide sheave for guiding the hook hoisting rope to the upper spreader during crane assembly / disassembly. There is no need to provide a guide sheave dedicated to the movement of the upper spreader while taking the technique of moving the upper spreader between the boom proximal end side and the distal end side using the upper rope and the jib hoisting rope.

  Therefore, since the weight increase on the boom tip side (around the strut) is eliminated, it is advantageous in terms of work capability and the cost can be reduced.

Moreover , the tension | tensile_strength of a jib hoisting rope can be kept in the range of the appropriate value preset about each of the high tension side and the low tension side by the winch control action by a control means.

In this case, the invention of claim 2 prevents over-tension by automatically stopping the winch operation in the direction in which the rope tension increases when the rope tension exceeds the stop set value exceeding the appropriate value on the high tension side. Rope breakage and structural damage can be prevented, and loosening is prevented by automatically stopping the winch movement in the direction in which the rope tension decreases when the value is below the set stop value below the appropriate value on the low tension side. The occurrence of random winding can be avoided.

On the other hand, in the invention of claim 3, when the rope tension becomes equal to or higher than the deceleration setting value exceeding the appropriate value on the high tension side, the winch operation in the direction in which the rope tension increases is decelerated, and the rope tension is less than the appropriate value on the low tension side. Since the winch movement in the direction in which the rope tension decreases when the speed becomes less than the deceleration setting value is decelerated , the work efficiency can be increased by continuing the work as long as the rope tension does not reach the danger range, compared with the case where the rope tension is suddenly stopped. It will be good.

According to the present invention 請 Motomeko 4 detects the boom angle by the boom angle detecting means, for regulating the winch operating condition that the boom angle is an angle when the crane assembly and disassembly (e.g. 25 ° or less), for example, It is possible to prevent erroneous control due to a switch operation error, such as when it is determined that assembly / disassembly is performed only by operating the mode switch.

On the other hand, according to the fifth and sixth aspects of the invention, the spreader guide means (the boom side rail and the upper spreader side roller in claim 6) can smoothly move the upper spreader along the boom upper surface. There is no risk of damage to the boom or upper spreader due to movement.

Prior to the description of the embodiment of the present invention, a reference embodiment as a basis will be described with reference to FIGS.

State during crane operation shifting Doshiki crane 1 (assembled state), respectively crane CLAD process to Figures 2-7.

  In each figure, 1 is a crawler type lower traveling body, and 2 is an upper revolving body mounted on the lower traveling body 1 so as to be able to swivel. These constitute a base machine A, and the upper revolving body of the base machine A A boom (tower) 3 is mounted on 2 by a boom foot pin 4 so as to be raised and lowered.

  A jib 5 projects from the tip of the boom 3, and the jib 5 is raised and lowered (in the luffing type, the boom 3 is also raised and lowered) to perform a crane operation.

  The jib hoisting device for raising and lowering the jib 5 includes a jib hoisting winch 6 mounted on the upper swing body 2 of the base machine A, a jib hoisting rope 7 wound / rewinded by the jib hoisting winch 6, The lower and upper spreaders 8 and 9 on which the jib hoisting rope 7 is multi-staged, and the struts 10 rotatably attached to the top of the boom around a horizontal axis are provided. The upper spreader 9 and the struts 10 are connected by a strut guy line 11. In addition, the strut 10 and the jib tip are connected by a jib guy line 12, respectively.

  The strut 10 receives a forward / backward turning moment due to the weight of the strut, a forward tilting moment due to the weight of the jib 5, and a backward tilting moment due to the winding force of the jib hoisting rope 7. The jib 5 is supported while rotating in the front-rear direction in accordance with the undulation of the jib 5 by the supporting force of the jib undulation rope 7 that opposes this.

  The jib hoisting rope 7 is multi-staged between the sheaves of the lower and upper spreaders 8 and 9, and the end of the jib hoisting rope 7 is connected to the lower spreader via a load cell 13 (see FIG. 3) as tension detecting means for detecting the tension of the rope 7. 8 is fixed.

  A strut mast 14 with a sheave is provided at the top of the boom as means for holding the strut guy line 11 above the boom during assembly / disassembly.

  On the other hand, the hook hoisting device for hoisting / unwinding the hoisting hook 15 from the tip of the jib includes a hook hoisting winch 16 mounted on the upper swing body 2 of the base machine A, and the hook hoisting winch. 16 and a hook hoisting rope 17 which is wound / rewinded by the hook 16 and is hooked between the hanging hook 15 and the jib tip sheave 18 and is fastened to the jib tip.

  Here, a hook hoisting guide sheave 19 is attached to the intermediate portion in the height direction of the strut mast 14 so as to be rotatable about a horizontal axis in the left-right direction, and the hook hoisting rope 17 is attached to the hook hoisting guide sheave 19 at the base of the boom. From the side to the tip side.

  The hook hoisting rope 17 passed through the sheave 19 is guided to the tip end side of the jib during the crane operation shown in FIG. 1, and is folded back to the boom base end side as shown in FIG. Is fastened to the upper spreader 9 (this fastening portion is shown enlarged in FIG. 3).

  Moreover, as shown in FIGS. 3 and 4, the boom upper surface (the upper surface in a state where the boom 3 is tilted to the ground as shown in FIG. 2 and the like over a certain section from the base end side to the tip end side of the boom. A pair of left and right rails 20 and 20 on which the upper spreader 9 is placed are provided, and rollers 21 and 21 that roll on the rails 20 and 20 are provided on the lower surface of the upper spreader 9, These constitute spreader guide means for moving and guiding the upper spreader 9 between the boom proximal end side and the distal end side.

  FIG. 3 shows a state in which the upper spreader 9 for raising and lowering the jib is placed on the upper surface on the base end side of the boom 3 before being connected to the strut guy line 11, and the boom raising and lowering rope folded back by the hook winding guide sheave 19 The terminal 17 is fastened to the upper spreader 9 as shown in the figure, and the jib hoisting rope 7 is rewound while winding the rope 17.

  As a result, the upper spreader 9 is moved to the boom tip side along the boom upper surface while applying the guide action of the rails 20 and 20 and the rollers 21 and 21, and as shown in FIGS. The movement is stopped at a position where it can be connected to 11.

  Thereafter, as shown in FIG. 6 (b), the hook hoisting rope 17 is removed from the upper spreader 9, and the strut guy line 11 is connected instead, and the hook hoisting rope 17 is set to the working condition. Then, the boom 3 and the jib 5 are raised as shown in FIG. 7 to obtain the working posture shown in FIG.

  When disassembling the crane, the operation is performed in the reverse order of the above assembly.

  In this way, the hook hoisting guide sheave 19 originally provided at the top of the boom as a part of the hook hoisting device is also used as a guide sheave for guiding the hook hoisting rope 17 to the upper spreader 9 during crane assembly / disassembly. While assembling the attachment, a guide sheave dedicated to moving the upper spreader is attached to the top of the boom while the attachment is assembled while the upper spreader 9 is moved between the boom proximal end and the distal end by the hook hoisting rope 17 and the jib hoisting rope 7. There is no need to provide it separately.

  The upper spreader 9 can be smoothly moved along the boom upper surface by the boom-side rails 20 and 20 and the upper spreader-side rollers 21 and 21, and the boom 3 or the upper spreader 9 is damaged by the spreader movement. There is no fear.

Further, when the guide sheave 19 is fixed at a low position as in this reference embodiment, assembling and disassembling as compared with the case where the upper spreader 9 which is a heavy load is moved in the air as in the known art. Work can be performed safely and efficiently.

  FIG. 8 shows the configuration of the hydraulic circuit and control system of the jib undulation and hook winding winches 6,16.

  In the figure, 23 is a hydraulic motor (hereinafter referred to as a jib undulation motor) that is a drive source of the jib hoisting winch 6, and 24 is a hydraulic motor (hereinafter referred to as a hook hoisting motor) that is a drive source of the hook hoisting winch 16. The motors 23 and 24 are controlled by hydraulic pilot control valves 25 and 26, respectively.

  The pilot lines of the control valves 25 and 26 are provided with both winding-side and rewinding-side electromagnetic proportional valves 29 and 30, respectively. The secondary pressure (pressure corresponding to the operation amount) of the remote control valves 27 and 28 is proportional to the electromagnetic proportionality. Controlled by valves 29 and 30.

  The electromagnetic proportional valves 29 and 30 are controlled by a signal from the controller 31 constituting the control means, whereby the stroke operation of the control valves 25 and 26, that is, the operation of both the motors 23 and 24 (winding / rewinding operation). ) Is controlled.

  The controller 31 receives, as input signals, remote control pressures corresponding to the operation of the remote control valves 27 and 28 by the pressure sensors 32 and 33, and signals from the assembly / disassembly mode switch 34 operated during assembly and disassembly, The tension signal from the load cell 13 that detects the tension of the jib hoisting rope 7 and the boom angle signal from the boom angle meter 35 that detects the boom angle are taken in via the overload prevention device 36 that is standard on the crane, A winch (motor) control for synchronizing the jib undulation and hook hoisting ropes 7 and 17 is performed based on these input signals during assembly and disassembly.

  The operation of this point will be described with reference to the flowchart of FIG.

  For example, at the time of assembly, basically, the jib hoisting remote control valve 27 is operated on the rewinding side, and the hook hoisting remote control valve 28 is operated on the winding side, so that the jib hoisting motor 23 is rotated while rewinding. The upper motor 24 is wound and rotated.

  As a result, the hook hoisting rope 17 is wound up while the jib hoisting rope 7 is rewound, and the upper spreader 9 moves from the boom proximal end side to the distal end side.

  At this time, the operator appropriately rotates or stops the jib hoisting motor 23 or rotates or stops the hook hoisting motor 24 while observing the tension state of the ropes 7 and 17 for raising and lowering the jib. Sometimes.

  After the control is started, it is determined whether or not the assembly / disassembly mode is selected in step S1 (whether the assembly / disassembly mode switch 34 has been operated by the operator), and in step S2, the boom angle is set to the angle at assembly / disassembly ( For example, if it is YES, it is determined that assembly / disassembly is in progress (not a normal crane working state).

  In this way, since the assembly / disassembly time is determined based on the two conditions of the switch operation and the boom angle, there is a risk of erroneous determination due to an erroneous operation such as when determining based on only the operation of the assembly / disassembly mode switch 34. Absent.

  Thereafter, the tuning control after step S3 is entered.

That is, in step S3, the tension of the jib hoisting rope 7 is lower than the dangerous tension that may cause the boom breakage or the like, but is set to a value close to the first set value (the deceleration setting on the high tension side in claim 3 ). Value) or more.

  In the case of YES here, as a first step, in order to decelerate the winding operation of the jib undulation and hook hoisting ropes 7, 17 which are movements in the direction in which the rope tension increases, the winding is performed from the controller 31 in step S4. A deceleration command signal is output to the take-side electromagnetic proportional valves 29 and 29.

Next, in step S5, it is determined whether or not the rope tension is equal to or higher than a second set value (stop setting value on the high tension side in claim 2 ) set in advance as a value that may cause boom breakage or the like.

  In the case of YES here, as a second stage, in order to stop the winding operation of the jib undulation and hook hoisting ropes 7 and 17 which are movements in the direction in which the rope tension increases, the winding from the controller 31 in step S6. A stop command signal is output to the take-side electromagnetic proportional valves 29, 29, and the process returns to step S1.

  If NO in step S1 (when the assembly / disassembly mode switch 34 is not operated), if NO in step S2 (if the boom angle condition during assembly / disassembly is not satisfied), NO in step S3. In this case (when the rope tension is less than the first set value), it is determined that the tuning control is not necessary, and the process proceeds to step S7, and a normal command signal is output to the winding side electromagnetic proportional valves 29 and 29.

  Here, the normal command signal basically refers to a signal that does not limit the secondary pressure of the remote control valves 27 and 28. However, when speed control is performed by an external command means such as a trimmer, this external command signal is used. Control signal based on

  If NO in step S5 (if the rope tension is less than the second set value), the process directly returns to step S1.

  With such control, when assembling the attachment by itself, the upper spreader 9 is boomed while keeping the tension of the ropes 7 and 17 within an appropriate range while maintaining the synchronization of the ropes 7 and 17 for raising and lowering the jib. It can be moved from the proximal side to the distal side.

  Moreover, since the winding operation of the ropes 7 and 17 is decelerated at the first stage when the rope tension increases and is stopped even when this is insufficient, the rope tension is lower than when suddenly stopped. The work efficiency is improved by being able to continue the work as long as it does not reach the danger zone.

  Even when the upper spreader 9 is moved from the boom distal end side to the proximal end side at the time of disassembly, the control shown in the flowchart of FIG. 9 is performed for the operation of the jib undulation and hook hoisting ropes 7 and 17. Synchronization of both ropes 7 and 17 is ensured.

By the way, not only when both the jib undulation and hook hoisting are operated at the same time, but they may be operated one side at a time, so a signal is sent to the cab warning and warning lamps to make it easier for the operator to understand the rope tension status. In addition, the vehicle may be decelerated without stopping .

Implementation embodiment (see FIG. 10)
In the reference mode, a configuration is adopted in which only the operation in the direction in which the tension of the jib hoisting rope 7 increases is taken. It is desirable to restrict the movement in the direction of the movement.

The control contents of the implementation form Ru obtain the both functions is described by FIG. 10 on the basis of the reference embodiment.

  In step S11, it is determined whether or not it is assembling / disassembling, and in step S12, it is determined whether or not the boom angle is an angle when assembling / disassembling. Then, in step S13, it is determined whether or not simultaneous operation of jib hoisting rope unwinding and hook hoisting rope winding is performed based on signals from the pressure sensors 32 and 33 in FIG. Performs an action (winding deceleration or stopping action) that restricts the movement in the direction of increasing.

In implementation form, in the case of NO in step S14 (if the rope tension is less than the first set value), at step S18, advance as higher than the value rope tension at risk of Ranmaki the value close to the It is determined whether or not the set third set value (<first set value. Deceleration set value on the low tension side in claim 3 ) or less.

  In the case of YES here, in order to decelerate the rewinding operation of the ropes 7 and 17 of the jib undulation and the hook hoisting ropes 7 and 17 which are the movements in the direction in which the rope tension further decreases, in step S19, the rewinding side electromagnetic proportionality from the controller 31 A rewind deceleration command signal is output to the valves 30 and 30.

Next, in step S20, it is determined whether or not the rope tension is equal to or less than a fourth set value (<third set value, the stop set value on the low tension side in claim 2 ) set in advance as a value at risk of random winding. To be judged.

  In the case of YES here, as a second stage, in order to stop the unwinding operation of the jib undulation and hook hoisting ropes 7 and 17 which are movements in the direction of decreasing rope tension, the controller 31 unwinds in step S21. A stop command signal is output to the return-side electromagnetic proportional valves 30 and 30, and the process returns to step S1.

  In the case of NO in step S11 (when the assembly / disassembly mode switch 34 is not operated), in the case of NO in S12 (when the boom angle condition during assembly / disassembly is not satisfied), and in step S18, NO. In the case of (when the rope tension is equal to or greater than the third set value), the process proceeds to step S22, and after the normal command signal is output to the rewinding-side electromagnetic proportional valves 30, 30, the process returns to step S1.

  If NO in step S20 (if the rope tension is greater than or equal to the fourth set value), the control returns to step S1 as it is without requiring control.

  This action can prevent not only the jib undulation and the over tension of the ropes 7 and 17 on the hook winding, but also the occurrence of the rope winding due to the rope tension becoming too low.

  Also in this case, when the rope tension is lowered, the first stage is decelerated, and even when this is insufficient, the work efficiency is improved compared with the case where the rope tension is suddenly stopped.

  In addition, since it is determined whether the simultaneous operation of the jib hoisting rope unwinding and the hook hoisting rope winding is performed based on the signals from the pressure sensors 32 and 33, more reliable and safe control can be performed.

Other embodiments
(1) In the above embodiment, the configuration is such that the tension of the jib hoisting rope 7 is directly detected by the load cell 13 provided at the point where the rope 7 is fixed to the lower spreader 8, but the load of the jib hoisting winch 6 ( A configuration may be adopted in which the detection is indirectly performed by the load pressure of the jib hoisting motor 23) or the like.

  (2) In the above embodiment, the jib undulation and the winding and unwinding operations of the hook winding ropes 7 and 17 are simultaneously decelerated or stopped, but based on the signals of the pressure sensors 32 and 33, If it is determined that one of the ropes is not operated, only the other operation may be decelerated or stopped.

  (3) Instead of the configuration using the rails 20 and 20 and the rollers 21 and 21 of the above-described embodiment as the spreader guide means, a slide guide plate made of a material having good slippage is provided over the base end side and the tip end side on the boom top surface The upper spreader 9 may be slid on the slide plate.

It is a schematic side view of the crane working state of the mobile crane concerning the reference form of this invention. It is a schematic side view of the state which mounted the upper spreader in the boom base end side in the middle of the assembly of the crane. FIG. 3 is a partially enlarged plan view of the state of FIG. 2. It is the IV-IV line expanded sectional view of FIG. It is a schematic side view of the state which moved the upper spreader to the boom tip side from the state of FIG. (B) is a partially enlarged view of the state where the upper spreader and the strut guy line are further connected. It is a schematic side view in the middle of raising a boom and a jib from the state of FIG. It is a figure which shows the structure of the motor hydraulic circuit of the jib hoisting and hook winding both winches in the crane, and its control system. It is a flowchart which shows the control content for taking the synchronization of both the jib undulation and hook hoisting rope at the time of the upper spreader movement in the crane. Jib hoist at the upper spreader moves in a mobile crane according to the implementation embodiments of the present invention, is a flow chart showing the contents of control for taking tuning on both rope hook winding.

Explanation of symbols

A Base machine 3 Boom 5 Jib 6 Jib hoisting winch 7 Jib hoisting rope 8 Lower spreader constituting the jib hoisting device 9 Same, upper spreader 10 Same, strut 11 Same, strut guy line 12 Same, jib guy line 13 Load cell 15 as tension detecting means 15 Hanging hook 16 Hook hoisting winch constituting hook hoisting device 17 Hook hoisting rope 19 Hook hoisting guide sheave 23 Jib hoisting winch hydraulic motor 24 Hook hoisting winch hydraulic motor 29, 30 Control means Constructing proportional solenoid valve 31 Same as above, controller

Claims (6)

Boom base machine, jib mounted for undulations respectively on the tip of the boom, and mobile cranes, characterized in that it comprises a requirement of the following (1) to (4).
(1) The jib hoisting device for hoisting the jib is composed of a jib hoisting winch mounted on the base machine, a jib hoisting rope wound and unwound by the jib hoisting winch, and the jib hoisting rope. Lower and upper spreaders for raising and lowering the jib, a strut attached to the top of the boom so as to be pivotable in the longitudinal direction about a horizontal axis, a jib guy line connecting the strut and the jib, the strut and the upper The upper spreader is configured to be movable between the proximal end side and the distal end side along the upper surface of the boom when the crane is assembled and disassembled.
(2) A hook hoisting device that suspends and raises a suspension hook from the tip of the jib is a hook hoisting winch mounted on a base machine, and a hook that is wound and unwound by the hook hoisting winch. A hoisting rope and a hook hoisting guide sheave for guiding the hook hoisting rope from the top of the boom toward the jib tip side.
(3) The hook hoisting guide sheave is configured so that the hook hoisting rope can be folded and guided along the upper surface of the boom toward the upper spreader placed on the boom base end side during crane assembly / disassembly. It is provided on the top of
(4) Tension detecting means for detecting the tension of the jib hoisting rope and control means for regulating the operations of the jib hoisting winch and the hook hoisting winch, the control means comprising the upper spreader during crane assembly / disassembly. So that the rope tension detected by the tension detecting means during the movement is within the range of appropriate values set in advance on the high tension side and the low tension side, respectively, and the operations of the jib undulation and hook winding winches are regulated. To be configured. Control means automatically stops the direction of winch operation rope tension is increased when the rope tension being detected becomes stopped more than the set value that exceeds the appropriate value of the high-tensile-side, low tension side of the proper value mobile crane according to claim 1, wherein the rope tension is configured to automatically stop the direction of winch operation decreases when it becomes less than the following stopping setpoint. The control means decelerates the winch movement in the direction in which the rope tension increases when the detected rope tension exceeds the high-strength-side deceleration setting value, and the deceleration setting is below the low-tension side appropriate value. The mobile crane according to claim 1 or 2, wherein the mobile crane is configured to decelerate a winch operation in a direction in which the rope tension decreases when the value becomes equal to or less than a value. Boom angle detection means for detecting the boom angle is provided, and the control means is configured to regulate the winch operation on condition that the boom angle detected by the boom angle detection means is an angle at the time of crane assembly / disassembly. mobile crane according to any one of claims 1 to 3, characterized in that it is. Mobile according to claim 1 in which the spreader guide means for moving the guide to and from the boom base end side along the upper spreader boom top and the distal end side, characterized in that vignetting set crane. As spreader guide means, rails on the upper surface of the boom, the mobile crane according to claim 5, wherein the roller rolling on the rail in the upper spreader is characterized in that provided we were respectively.

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