JP6550328B2 - crane - Google Patents

Description

  The present invention relates to a crane.

  Heretofore, an overload prevention device has been mounted on a crane to prevent an overload from being applied at the time of a lifting operation. Patent Document 1 below discloses an example of such an overload prevention device.

  The overload prevention device disclosed in Patent Document 1 has storage means in which a plurality of work performances are stored according to a plurality of states at the time of a lifting operation of a crane. The storage means stores the work performance for each state of the jib work, the boom work and the jibed boom work. The jib work is a work of suspending a hanging load from the tip of the jib while the jib is mounted on the boom so as to extend from the tip of the boom. The boom operation is an operation of suspending a hanging load from the tip of the boom while the jib is stored along the boom. The jibed boom operation is an operation of suspending a hanging load from the tip of the boom while the jib is attached to the boom so as to extend from the tip of the boom.

  In this overload prevention device, the crane lifting operation is performed based on the type of work manually set using the work setting means and the detection result by the jib storage detection means for detecting whether the jib is in the storage state or not. The state of the hour is derived. Then, the work performance according to the derived state is selected from the plurality of work performance stored in the storage means. Then, based on the selected work performance, the limit value corresponding to the detection value of the boom length, the boom hoisting angle and the turning angle is calculated. The overload prevention device regulates the operation of each drive of the crane when the detected value of the load acting on the boom reaches the calculated limit value, thereby preventing the overload from being applied.

  As described above, in the overload prevention device disclosed in Patent Document 1, the limit value is not set uniformly, but the limit value corresponding to each state at the time of the lifting operation of the crane is set. For this reason, the crane can exhibit the highest possible lifting capacity in each state at the time of the lifting operation.

Unexamined-Japanese-Patent No. 2002-211884

  By the way, some cranes are equipped with a winch configured to rotate a winch drum with a plurality of electric motors to perform lifting and lowering of a hanging load as a hanging operation winch. In such a hanging operation winch, it is assumed that a failure occurs in any of the plurality of motors. In this case, the lifting capacity of the crane is reduced compared to the lifting capacity when all the motors are operating normally without failure.

  However, in the conventional overload prevention device described above, since the lowering of the suspension capacity caused by the failure of the motor for the hoisting work winch is not assumed, the above overload protection device mounted such a hoisting work winch In the case of being used for a crane, there is a possibility that the lifting operation may be performed in a state where it is permitted to apply a load (hanging load) exceeding the lifting capacity which is reduced due to the failure of the motor. That is, the certainty of overload prevention is lost.

  On the other hand, when emphasis is placed on the certainty of overload prevention, the set suspension capacity value (limit value), which serves as a judgment standard for overload prevention, is reduced to 0 when any of a plurality of motors fail. It is also conceivable that the overload prevention device immediately shuts down the operation of all the motors. However, in this case, even if the remaining motors other than the failed motor can operate normally, the operation of the motor is also stopped. That is, although the winch drum can be rotated by the remaining normally operable motors to exhibit a certain level of suspension capability, no lifting operation can be performed.

  This invention was made in order to solve said subject, The objective is the case where any one of several electric motors fails in the crane which rotates the winch drum for suspension operations by several electric motors. Also, while ensuring the certainty of overload prevention, it is possible to continuously carry out the hanging operation within the possible range.

  In order to achieve the above object, a crane according to the present invention is a crane for hoisting or lowering an object, wherein a winch drum is provided to rotate for hoisting or lowering the object, and power is supplied. Are derived by a plurality of electric motors each outputting a drive torque for operating the winch drum to rotate, the load deriving unit deriving the load value of the object applied to the winch drum, and the load deriving unit An overload preventing device for monitoring the value of the load and stopping the operation of each of the plurality of motors to stop the rotation of the winch drum when the value of the load exceeds the set suspension capacity value of the crane; And a specifying unit that specifies a failed motor among the plurality of motors, and the overload prevention device stores the set suspension capacity value. And a maximum load calculating unit that calculates the maximum load that the winch drum can wind up based on the driving torques output from the remaining motors other than the failed motor specified by the specifying unit; The control unit further includes: an updating unit that updates the stored setting suspension capacity value to a value equal to the maximum load calculated by the maximum load calculating unit; and a control unit that controls the plurality of electric motors. The unit stops the operation of the failed motor specified by the specifying unit, and the load value derived by the load deriving unit is less than or equal to the latest set suspension capacity value stored in the storage unit. In some cases, the remaining motors are operated, and when the value of the load derived by the load deriving unit exceeds the latest set suspension capacity value, Performs control to stop the movement.

  In this crane, when the malfunctioning motor is identified by the identification unit, the maximum load that the winch drum can wind up with the driving torque output from the remaining motors other than the identified malfunctioning motor is the maximum load calculation unit Is calculated and stored in the storage unit is updated to a value equal to the maximum load calculated by the maximum load calculation unit. And when the load value derived | led-out by the load derivation | leading-out part exceeds the newest setting suspension capability value memorize | stored in the memory | storage part, a control part stops operation of each motor, As a result, rotation of a winch drum is It is stopped. For this reason, the certainty of the overload prevention in the case where one of the motors breaks down can be secured. On the other hand, when the load value derived by the load deriving unit is equal to or less than the latest set suspension capacity value stored in the storage unit, the control unit operates the remaining motors other than the failed one. The winch drum can be rotated by the driving torque output from the remaining motors. That is, although the lifting capacity of the crane is limited as compared with the case where all the motors are not broken, the lifting operation can be carried out continuously with the maximum lifting capacity as much as possible.

  The crane is a notification unit for notifying the operator of the crane that the set suspension capacity value has been updated in response to the update unit updating the set suspension capacity value stored in the storage unit. It is preferable to further include.

  According to this configuration, the operator can know that the setting suspension capability value has been updated by the notification of the notification unit. Also, the operator can recognize that a failure has occurred in any of the motors by the notification. This can prevent the user from forgetting to repair or maintain the failed motor.

  In this case, preferably, the notification unit is a display device that displays the updated setting suspension capability value.

  According to this configuration, the operator can know the set suspension capacity value after the update by looking at the display of the display device. For this reason, the operator can select to suspend an object having a load that does not exceed the updated setting suspension capacity value in the suspension operation.

  The crane has a permission input unit for inputting an instruction for permitting the update of the set suspension capacity value, and the update unit of the set suspension capacity value in response to the instruction being input to the permission input unit. The update permission unit further includes an update permission unit for giving permission for the update, and the update unit is configured to set the suspension in response to the specified motor specifying the failed motor and the update permission unit giving permission for the update. It is preferable to update the ability value.

  According to this configuration, even if the malfunctioning motor is identified by the identification unit, the setting suspension stored in the storage unit is not input unless the operator inputs an instruction for permitting the update of the setting suspension capacity value to the permission input unit. The ability value is not updated. That is, the operator can perform permission to update the set suspension capacity value by his own intention when the failed motor is identified. Therefore, the operator can surely recognize that the set suspension capacity value has been updated.

  As described above, according to the present invention, even if one of the plurality of motors fails in a crane in which the winch drum for hanging work is rotated by the plurality of motors, certainty of overload prevention is ensured. However, it is possible to carry out the hanging work to the extent possible.

1 is a schematic side view of a crane according to an embodiment of the present invention. It is a mimetic diagram showing the system configuration of the crane by one embodiment of the present invention. It is a figure which shows correlation with the working radius registered into the suspension capacity database, and the setting suspension capacity value. It is a figure which shows the example of the specific screen of the failure motor of a display apparatus. It is a figure which shows the example of the update alerting | reporting screen of the setting suspension capacity value of a display apparatus. FIG. 6 is a flow chart illustrating the process of handling a failure of any of the motors of the hoisting winch in the crane according to an embodiment of the present invention. FIG. It is a schematic diagram which shows the system configuration of the crane by the 1st modification of one embodiment of the present invention. It is a schematic diagram which shows the system configuration | structure of the crane by the 2nd modification of one Embodiment of this invention. It is a flowchart which shows the processing process when failure generate | occur | produces in the electric motor of a winding winch in the crane by said 2nd modification. It is a schematic diagram which shows the structure of the winding winch of the crane by the 3rd modification of one Embodiment of this invention. It is a schematic diagram which shows the structure of the winding winch of the crane by the 4th modification of one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The crane according to an embodiment of the present invention is, as shown in FIG. 1, a self-propelled lower traveling body 2 and an upper portion mounted on the lower traveling body 2 so as to be pivotable about a turning center axis C. And a rotating body 4.

  The upper revolving superstructure 4 is provided with a work device 8 for performing a hanging operation of the load 100, that is, a crane operation. The working device 8 has a boom 10, a hook device 12, a relief device 14 and a hoisting winch 15.

  The boom 10 is provided on the upper swing body 4 so as to be able to be raised and lowered with a boom foot (not shown) at the base end thereof as a fulcrum. The hook device 12 is for suspending the load 100. The hook device 12 is suspended from the tip of the boom 10 via a suspending rope 13. In addition, the target object 101 which the crane of this embodiment carries out raising and lowering by hanging operation consists of the hook apparatus 12 and the hanging load 100 suspended by the hook apparatus 12.

  The undulating device 14 includes a undulating winch 16, a lower spreader 17, an upper spreader 18, a gantry 19, and a guy rope 20.

  The lower spreader 17 is provided at an upper end portion of a gantry 19 erected at the rear of the upper swing body 4. The upper spreader 18 is provided apart from the lower spreader 17. An undulation rope 21 drawn from an undulation winch 16 is wound around the sheave of the lower spreader 17 and the sheave of the upper spreader 18. The guy rope 20 connects the upper spreader 18 and the tip of the boom 10. The undulation winch 16 changes the distance of the upper spreader 18 relative to the lower spreader 17 by winding / unwinding the undulation rope 21, thereby undulating the boom 10 via the guy rope 20.

  The hoisting winch 15 is mounted on the upper swing body 4. A lifting rope 13 pulled out of the hoisting winch 15 is connected to the hook device 12 through the tip of the boom 10. The hoisting winch 15 winds up / down the hook device 12 by winding up / unwinding the lifting rope 13 and thereby winds up / down the object 101.

  Specifically, the hoisting winch 15 is an electric winch. The hoisting winch 15 includes a winch drum 24 (hereinafter simply referred to as a drum 24), a plurality of electric motors 26 (see FIG. 2), a torque transmission device 28 (see FIG. 2), and a plurality of corresponding motors 26. And a mechanical brake 30.

  The drum 24 rotates to roll up or down the object 101. Specifically, the drum 24 winds the lifting rope 13 by rotating in the winding direction, which is one rotation direction, and thereby winds up the object 101. In addition, the drum 24 unwinds the lifting rope 13 by rotating in the winding direction, which is the rotation direction opposite to the winding direction, whereby the object 101 is lowered.

  The plurality of motors 26 (see FIG. 2) are electrically connected to the power supply 29 mounted on the crane. Each of the motors 26 is operated by being supplied with power from the power source 29 and outputs a driving torque for rotating the drum 24. In the present embodiment, the hoisting winch 15 has two motors 26. One of the two motors 26 is referred to as a first motor 31, and the other is referred to as a second motor 32.

  The torque transfer device 28 (see FIG. 2) collectively transmits the drive torques output from the plurality of motors 26 to the drum 24. Specifically, the torque transfer device 28 is connected to the drive shaft 31 a of the first motor 31 and the drive shaft 32 a of the second motor 32. Thereby, the drive torque of both the electric motors 31 and 32 is input into the torque transmission apparatus 28 from those drive shafts 31a and 32a. The torque transfer device 28 synthesizes the drive torques input from the drive shafts 31a and 32a. Further, the torque transmission device 28 is connected to the rotation shaft 24 a of the drum 24. Thus, the torque transfer device 28 applies the combined drive torque to the rotating shaft 24a. That is, the driving torque of the sum of the driving torque output from the first electric motor 31 and the driving torque output from the second electric motor 32 is input to the rotating shaft 24 a of the drum 24. Thereby, the drum 24 is rotated.

  Each mechanical brake 30 is attached to a corresponding electric motor 26, respectively. In the present embodiment, the hoisting winch 15 has two mechanical brakes 30. One of the two mechanical brakes 30 is attached to the first electric motor 31, and the other is attached to the second electric motor 32. One mechanical brake attached to the first electric motor 31 is referred to as a first mechanical brake 33, and the other mechanical brake attached to the second electric motor 32 is referred to as a second mechanical brake 34.

  The first mechanical brake 33 is configured to be switchable between the locked state and the unlocked state. In the locked state, the first electric motor 31 is kept in the operation stop state by braking the first electric motor 31. The unlocked state is a state in which the braking on the first motor 31 is released to make the first motor 31 operable.

  Specifically, the first mechanical brake 33 fixes the drive shaft 31a so that the drive shaft 31a of the first motor 31 does not rotate in the locked state, and releases the fixed state of the drive shaft 31a in the unlocked state. The drive shaft 31a is made rotatable. The first mechanical brake 33 is switched between the locked state and the unlocked state by a control unit 63 of the overload prevention device 48 described later. Specifically, the first mechanical brake 33 is unlocked when the control signal, which is an electric signal, is input from the control unit 63, and is locked when the input of the control signal from the control unit 63 is stopped. It is configured to be in the state.

  The second mechanical brake 34 is configured to be switchable between the locked state and the unlocked state. In the locked state, the second electric motor 32 is kept in the operation stop state by braking the second electric motor 32. In the unlocked state, the braking on the second motor 32 is released to make the second motor 32 operable.

  Specifically, the second mechanical brake 34 fixes the drive shaft 32a so that the drive shaft 32a of the second motor 32 does not rotate in the locked state, and releases the fixed state of the drive shaft 32a in the unlocked state. The drive shaft 32a is made rotatable. The second mechanical brake 34 is controlled to switch between the locked state and the unlocked state by a control unit 63 of the overload prevention device 48 described later. Specifically, the second mechanical brake 34 is unlocked when the control signal, which is an electric signal, is input from the control unit 63, and is locked when the input of the control signal from the control unit 63 is stopped. It is configured to be in the state.

  Further, as shown in FIG. 2, the crane according to the present embodiment includes a first switch 36, a second switch 37, a setting unit 40, an angle detector 42, a load detector 44, and a specifying unit 46. An overload prevention device 48 and a display device 49 are provided.

  The first switch 36 is provided in the electrical path between the power source 29 and the first motor 31. The first switch 36 is configured to switch between the on state and the off state. The on state is a state in which the power supply 29 and the first motor 31 are conducted to allow the supply of power from the power supply 29 to the first motor 31. The off state is a state in which the conduction between the power source 29 and the first motor 31 is cut off to stop the supply of power from the power source 29 to the first motor 31. The first switch 36 is controlled to switch between the on state and the off state by a control unit 63 of the overload prevention device 48 described later.

  The second switch 37 is provided in the electrical path between the power source 29 and the second motor 32. The second switch 37 is configured to switch between the on state and the off state. The on state is a state in which the power supply 29 and the second motor 32 are conducted to allow the supply of power from the power supply 29 to the second motor 32. In the off state, the conduction between the power source 29 and the second motor 32 is cut off to stop the supply of power from the power source 29 to the second motor 32. The second switch 37 is controlled to switch between the on state and the off state by a control unit 63 of the overload prevention device 48 described later.

  The setting unit 40 is for inputting various setting values regarding the crane. Specifically, the setting unit 40 inputs the axial length of the boom 10 (see FIG. 1), that is, the distance from the boom foot to the tip of the boom 10 and other setting values. The data of the setting value input by the setting unit 40 is input to the overload prevention device 48 (see FIG. 2).

  The angle detector 42 detects the ups and downs of the boom 10 (see FIG. 1). Specifically, the angle detector 42 always detects the up-and-down angle which is an angle formed by the boom 10 with respect to a plane orthogonal to the swing center axis C of the upper swing body 4. The angle detector 42 sequentially outputs data of the detected elevation angle of the boom 10 to the overload prevention device 48 (see FIG. 2).

  The load detector 44 is an example of a load deriving unit in the present invention. The load detector 44 detects the load of the object 101 (see FIG. 1) applied to the drum 24. Specifically, the hanging rope 13 is connected to the load detector 44. The load detector 44 always detects the load applied to the drum 24 from the hanging rope 13. The load detector 44 sequentially outputs data of the detected load value to the overload prevention device 48.

  The identifying unit 46 is for identifying the failed motor 26 among the plurality of motors 26. That is, when one or both of the first motor 31 and the second motor 32 fail, the identifying unit 46 identifies the failed motor. In the present embodiment, since the specifying unit 46 is incorporated in the display device 49, a specific configuration of the specifying unit 46 will be described together with the display device 49 described later.

  The overload prevention device 48 monitors the value of the load detected by the load detector 44. The overload prevention device 48 stops the operation of each motor 26 to stop the rotation of the drum 24 when the value of the load detected by the load detector 44 exceeds the set suspension capacity value of the crane, thereby the target The winding up or lowering of the object 101 is stopped. As shown in FIG. 2, the overload prevention device 48 includes a storage unit 56, a maximum load calculation unit 58 as a functional block, an update unit 60, a work radius calculation unit 61, a suspension capacity value reading unit 62 and a control unit 63. Equipped with

The storage unit 56 stores various set values input from the setting unit 40, a specified value, and a set suspension capacity value of the crane. The set suspension capacity value is represented by the load value of the object 101 (see FIG. 1) on which the crane is suspended. The set suspension capacity value is set to a load value as large as possible within a range in which the boom 10 (see FIG. 1) can endure strength and in a range that does not impair the stability of the crane against tipping. The storage unit 56 stores the set suspension capacity value in the form of a suspension capacity database, as shown in FIG. The suspension capacity database defines the correspondence between the working radius R and the set suspension capacity value W at predetermined intervals of the crane. For example, as shown in FIG. 3, in the suspension capability database, set suspension capability values w ₀ , w ₁ , and so on corresponding to each work radius r ₀ , r ₁ , r ₂ , r ₃ ,. w ₂ , w ₃ , ... are specified.

  The maximum load calculation unit 58 (see FIG. 2) winds up the drum 24 by applying to the drum 24 the drive torques output from all the remaining motors 26 other than the failed motor 26 specified by the specifying unit 46. Calculate the largest possible load.

  The updating unit 60 calculates the set suspension capacity value of the suspension capacity database stored in the storage unit 56 by the maximum load calculation unit 58 in response to the specification of the broken motor 26 by the identification unit 46. Update to a value equal to the load.

  The working radius calculation unit 61 determines the distance from the pivoting center axis C in a plane orthogonal to the pivoting center axis C of the upper pivoting body 4 to the portion supporting the boom foot of the upper pivoting body 4 and prevents overload from the angle detector 42 Based on the elevation angle of the boom 10 input to the device 48, the working radius during the lifting operation of the crane is sequentially calculated. The distance from the pivot center axis C to the portion of the upper swing body 4 that supports the boom foot is the length and specified value of the boom 10 stored in the storage unit 56.

  The suspension capacity value reading unit 62 sequentially reads out the set suspension capacity value corresponding to the work radius sequentially calculated by the work radius calculation unit 61 from the latest suspension capacity database stored in the storage unit 56. In the case where the suspension radius value reading unit 62 determines that the radius of work calculated by the radius of operation calculation unit 61 is a value between two adjacent radiuses of each radius of operation registered in the suspension capacity database, The setting suspension capacity value corresponding to the two work radii is read from the latest suspension capacity database, and the setting suspension corresponding to the work radius calculated by the work radius calculation unit 61 by interpolation calculation from the read setting suspension capacity value Calculate the ability value.

  The control unit 63 performs control to allow the operation of each motor 26 and control to stop the operation of each motor 26.

  Specifically, when the broken motor 26 is not specified by the specifying unit 46, that is, in the normal state in which none of the plurality of motors 26 is broken, the control unit 63 overloads the load detector 44. If the detected load value input to the prevention device 48 is equal to or less than the set suspension capacity value read by the suspension capacity value reading unit 62 at that time, operation of all the motors 26 is permitted. On the other hand, when the broken motor 26 is not specified by the specifying unit 46, the control unit 63 determines that the load detection value input from the load detector 44 to the overload preventing device 48 is the suspension capacity reading unit at that time. If the set suspension capacity value read by 62 is exceeded, the operation of all the motors 26 is stopped.

  Further, when the failed motor 26 is specified by the specifying unit 46, the control unit 63 stops the specified motor 26. Then, in this case, when there is a remaining motor 26 other than the motor 26 specified by the specifying unit 46, that is, when there is a motor 26 in a normal state without failure, the control unit 63 If the detected load value input to the overload prevention device 48 is equal to or less than the set suspension capacity value read by the suspension capacity value reading unit 62 at that time, operation of the remaining electric motor 26 is permitted. On the other hand, when the remaining motor 26 is present, the control unit 63 reads the detected value of the load input from the load detector 44 to the overload preventing device 48 by the suspension capacity reading unit 62 at that time. When the set suspension capacity value is exceeded, the operation of the remaining motor 26 is stopped.

  The control unit 63 turns on the first switch 36 to allow the power supply 29 to supply electric power from the power supply 29 to the first electric motor 31 when the first electric motor 31 of the electric motors 26 is allowed to operate. The control signal is input to the first mechanical brake 33 to release the lock. Thereby, the control unit 63 operates the first electric motor 31. Further, when the operation of the first motor 31 is stopped, the control unit 63 turns off the first switch 36 to stop the supply of power from the power source 29 to the first motor 31 and the first mechanical brake 33. To stop the input of the control signal to the first mechanical brake 33 to lock it. Thereby, the control unit 63 stops the operation of the first electric motor 31.

  In addition, when allowing the operation of the second motor 32 among the motors 26, the control unit 63 turns on the second switch 37 to supply power from the power supply 29 to the second motor 32 and the second machine. The control signal is input to the brake 34 to unlock the second mechanical brake 34. Thereby, the control unit 63 operates the second motor 32. Further, when stopping the operation of the second motor 32, the control unit 63 turns off the second switch 37 to stop the supply of power from the power source 29 to the second motor 32, and the second mechanical brake 34. Stopping the input of the control signal to the second mechanical brake 34 to lock it. Thereby, the control unit 63 stops the operation of the second motor 32.

  The control unit 63 is configured to transmit a control signal instructing the on / off state to the first switch 36 and the second switch 37. Each of the switches 36 and 37 is turned on or off according to the control signal received from the control unit 63.

  The display device 49 displays various states of the crane on the screen. The display device 49 is an example of a notification unit in the present invention. Information on the output of the motor and the maximum torque is sequentially input to the display device 49 from each of the motors 26 (the first motor 31 and the second motor 32). The display device 49 switches and displays a specific screen (see FIG. 4) of the failed motor and an update notification screen (see FIG. 5) of the set suspension capacity value. The specific screen of the faulty motor is used by the crane operator to identify the faulty motor 26. The update notification screen of the setting suspension capacity value is for notifying the operator that the setting suspension capacity value of the suspension capacity database stored in the storage unit 56 has been updated.

  The specific screen (see FIG. 4) of the failed motor includes a first current display column 71, a second current display column 72, a first specification display column 73, and a second specification display column 74.

  The first current display column 71 is a place where the current actual output and maximum torque of the first electric motor 31 are displayed. The second current display column 72 is a place where the current actual output and maximum torque of the second motor 32 are displayed. The display device 49 displays the value of the output and the value of the maximum torque corresponding to the information of the output and the maximum torque input from the first electric motor 31 in the first current display column 71. Further, the display device 49 displays the value of the output and the value of the maximum torque corresponding to the information of the output and the maximum torque input from the second motor 32 in the second current display column 72.

  The first specification display field 73 is a place where the output and maximum torque defined as the specification of the first electric motor 31 are displayed. The second specification display column 74 is a place where the output and the maximum torque defined as the specification of the second motor 32 are displayed. The output value and the maximum torque value of the first motor 31 defined as the specification, and the output value and the maximum torque value of the second motor 31 defined as the specification are input to the display device 49 in advance. The display device 49 displays in the first specification display field 73 the output value and the maximum torque value of the first electric motor 31 as the specifications input in advance. Further, the display device 49 displays the output value of the second motor 32 and the value of the maximum torque as the specifications input in advance in the second specification display column 74.

  As shown in FIG. 2, the identification unit 46 is incorporated in the display device 49. The identifying unit 46 has a selecting unit 76 provided on the identifying screen (see FIG. 4) of the faulty motor and a signal output unit 77 incorporated in the display device 49.

  The selection unit 76 (see FIG. 4) is operated by the operator on the specific screen of the failed motor in order to select the failed motor 26. The operator moves the cursor in the state display column 78 of the first motor 31 and the state display column 79 of the second motor 32 by operating the selection unit 76 to set the state of each motor 31, 32 to a faulty state or You can select one of the non-failed normal states.

  The operator can use the actual output of the first motor 31 displayed in the first current display column 71 (see FIG. 4) in the specification of the first motor 31 displayed in the first specification display column 73 (see FIG. 4). If the difference is lower than the output and the difference exceeds the predetermined threshold value, it is determined that the first motor 31 has failed, and the selecting unit 76 is operated to select the failure state as the state of the first motor 31. . In addition, the operator has determined that the actual maximum torque of the first motor 31 displayed in the first current display column 71 is lower than the maximum torque of the specification of the first motor 31 displayed in the first specification display column 73 and that Even when the difference exceeds the predetermined threshold value, it is determined that the first motor 31 has failed, and the selecting unit 76 is operated to select the failure state as the state of the first motor 31. In addition, when the operator does not lower either the actual output of the first motor 31 or the maximum torque with a difference greater than or equal to the threshold value with respect to the corresponding values of the specifications, the state of the first motor 31 is Select normal condition.

  In addition, the operator makes the same judgment as in the case of the first motor 31 based on the output and the maximum torque respectively displayed in the second current display column 72 and the second specification display column 74 for the second motor 32. The selection unit 76 selects the state of the second motor 32.

  The signal output unit 77 outputs a signal indicating the state of the first motor 31 and the second motor 32 selected by the operation of the selection unit 76 to the overload prevention device 48.

  A status display field 80 and an update information display field 81 are provided at the top of the update notification screen (see FIG. 5) of the set suspension capacity value. The status display column 80 is a place where the status (normal status or failure status) of the first and second motors 31 and 32 is displayed. The update information display column 81 is a portion for displaying whether or not the set suspension capacity value has been updated. In the update notification screen, the correlation between the set suspension capacity value and the work radius corresponding to the suspension capacity database before the update, and the correlation between the set suspension capacity value and the work radius corresponding to the suspension capacity database after the update And a comparison display unit 82 that displays them side by side.

  The display device 49 displays the state of the first motor 31 in the state display column 80 corresponding to the state of the first motor 31 selected by the operation of the selection portion 76, and the second selected by the operation of the selection portion 76. The state of the second motor 31 is displayed in the state display column 80 in accordance with the state of the motor 32.

  From the overload prevention device 48, a signal indicating an update is input to the display device 49 in response to the updating unit 60 updating the setting suspension capacity value of the suspension capacity database stored in the storage unit 56. The display device 49 sets the suspension capacity in the update information display column 81 in response to the update unit 60 updating the set suspension capacity value, that is, in response to the signal from the overload prevention device 48 notifying the update. Display "Updated" indicating that the value has been updated. Further, the display device 49 indicates the correlation between the set suspension capacity value before update and the work radius and the set suspension capacity value after update and the work radius in response to the update unit 60 updating the set suspension capacity value. The correlation is shown in the comparison display unit 82.

  Next, a processing process performed when a failure occurs in the motor 26 in the crane of the present embodiment will be described.

  First, among the plurality of motors 26 of the winding winch 15, the specified unit 46 specifies a broken motor (step S1).

  Specifically, the operator of the crane looks at the first and second status display fields 71 and 72 and the first and second specification display fields 73 and 74 displayed on the specific screen of the failure motor of the display device 49. The states of the first motor 31 and the second motor 32 are individually determined. In the present embodiment, it is assumed that a failure occurs in the second motor 32 among the first motor 31 and the second motor 32, and the output and / or the maximum torque of the second motor 32 is reduced.

  As a result of the occurrence of a failure in the second motor 32, the actual output of the second motor 32 displayed in the second current display column 72 is lower than the output of the specification displayed in the second specification display column 74, and their outputs Or the actual maximum torque of the second motor 32 displayed in the second status display column 72 is lower than the maximum torque of the specifications displayed in the second specification display column 74 and those The difference in maximum torque may exceed a predetermined threshold. The operator judges that the second motor 32 has broken down in view of the situation of the output of the second motor 32 and the maximum torque. Then, the operator operates the selection unit 76 to move the cursor of the state display column 79 of the second motor 32 to the failure state, thereby specifying that the second motor 32 is in the failure state.

  In response to this specification, a signal indicating that the second motor 32 is in a failure state is output from the signal output unit 77 to the overload prevention device 48. Further, the first motor 31 is in a normal state without failure, and it is specified in the state display column 78 of the first motor 31 that the first motor 31 is in a normal state. Therefore, a signal indicating that the first motor 31 is in the normal state is output from the signal output unit 77 to the overload prevention device 48.

  Next, the control unit 63 stops the operation of the failed motor 26 specified by the specifying unit 46 (step S2). Specifically, as described above, control is performed according to a signal indicating that the second electric motor 32 is in the failure state, and it is specified that the second electric motor 32 is in the failure state and is input to the overload prevention device 48. The unit 63 stops the operation of the second motor 32. At this time, the control unit 63 turns off the second switch 37 to stop the supply of power from the power source 29 to the second motor 32, thereby stopping the operation of the second motor 32. On the other hand, since the first electric motor 31 is in a normal state and a signal indicating that fact is input from the signal output unit 77 to the overload prevention device 48, the control unit 63 responds to the signal and outputs the signal of the first electric motor 31. Allow operation.

  Thereafter, a series of processes (steps S3 to S8) for updating the setting suspension capacity value of the suspension capacity database stored in the storage unit 56 are performed.

First, the maximum load calculation unit 58 calculates the maximum load w _x that can be wound up by the drum 24 based on the driving torques output from the remaining motors 26 other than the motor 26 in the failure state specified by the specification unit 46 (step S3). ). Specifically, when only the maximum torque of the specification of the first electric motor 31 in a normal state is applied to the drum 24, the maximum load calculation unit 58 calculates the maximum load w _x that the drum 24 can wind up.

Next, the control unit 63 determines whether the maximum load w _x calculated by the maximum load calculation unit 58 is smaller than the set suspension capacity value corresponding to the predetermined work radius of the suspension capacity database stored in the storage unit 56 It is determined (step S4). Here, the control unit 63 determines whether or not the maximum load w _x is smaller than the set suspension capacity value w ₀ corresponding to the smallest operation radius r ₀ among the operation radii registered in the suspension capacity database.

If the control unit 63 determines that the maximum load w _x is smaller than the set suspension capacity value w ₀ , then the update unit 60 sets the working radius r ₀ of the suspension capacity database stored in the storage unit 56. the ability value w ₀ hanging corresponding set is updated to a value equal to the maximum load w _x (step S5).

On the other hand, the control unit 63, the maximum load w _x is not smaller than the capacity value w ₀ hanging set, that is, when it is determined that the set hanging capacity value w ₀ or more, the update unit 60, the storage unit 56 is directly maintained working radius r ₀ of the hanging capacity database without updating the set hanging capacity value w ₀ corresponding are (step S6).

After the above step S5 or S6, the control unit 63 sets the setting suspension capability values w ₀ , w _{1 of} all the work radiuses r ₀ , r ₁ , r ₂ , r ₃ , ... registered in the suspension capability database. , W ₂ , w ₃ ,..., It is determined whether or not the process of the above steps S4 to S6 for the update is completed (step S7).

Here, the control unit 63 does not complete the processing of the steps S4 to S6 for all the setting suspension capability values of the working radius, that is, the setting suspension of the working radius for which the processing of the steps S4 to S6 is not performed. If it is determined that the capability value exists, the set suspension capability value corresponding to the next operation radius not processed is set as the update target (step S8). That is, since that has the ability value w ₀ hanging set corresponding to the working radius r ₀ in step S4~S6 and updated, at the step S8, corresponding to the smallest operating radius r ₁ in the working radius of the untreated The set suspension capacity value w ₁ is set as an update target.

  Thereafter, the processing after step S3 is repeatedly performed. As a result, processing for updating the set suspension capacity value is performed in order from the smaller one of the work radiuses registered in the suspension capacity database.

Then, in step S7, the control unit 63 performs steps for all the set suspension capacity values w ₀ , w ₁ , w ₂ , w ₃ ,... Of the working radiuses r ₀ , r ₁ , r ₂ , r ₃ ,. If it is determined that the processing of S4 to S6 is completed, a series of processing for updating the set suspension capacity value of the suspension capacity database stored in the storage unit 56 is ended.

  In this embodiment, when the motor 26 in the failure state is specified by the specifying unit 46, the drum 24 is wound up with the driving torque output from the motor 26 in the normal state other than the motor 26 in the specified failure state. The maximum possible load is calculated by the maximum load calculator 58. Then, the set suspension capacity value of the suspension capacity database stored in the storage unit 56 is updated to a value equal to the maximum load calculated by the maximum load calculation unit 58. Then, when the load value detected by the load detector 44 exceeds the corresponding set suspension capacity value of the latest suspension capacity database stored in the storage unit 56, the control unit 63 stops the operation of each motor 26 As a result, the rotation of the drum 24 is stopped. For this reason, the certainty of the overload prevention in the case where one of the plurality of motors 26 breaks down can be secured.

  On the other hand, when the load value detected by the load detector 44 is equal to or less than the corresponding set suspension capacity value of the latest suspension capacity database stored in the storage unit 56, the controller 63 determines that the motor in the failure state is The remaining normal state motor 26 other than 26 is operated. Therefore, the drum 24 can be rotated by the driving torque output from the remaining electric motor 26. That is, although the suspension capacity is limited by updating the suspension capacity value of the suspension capacity database as compared with the normal state in which all the motors 26 are not broken, the suspension capacity value after the update is set The lifting operation can be carried out continuously with the maximum lifting capacity within the possible range defined in.

  Further, in the present embodiment, in response to the updating unit 60 updating the setting suspension capacity value of the suspension capacity database stored in the storage unit 56, the display device 49 updates the update notification screen of the setting suspension capacity value Display column 81 displays that the setting suspension capacity value of the suspension capacity database has been updated. Therefore, the operator can see the display to know that the set suspension capacity value has been updated.

  The display device 49 also displays the state (normal state or failure state) of each of the motors 31 and 32 in the state display column 80 of the update notification screen. Therefore, the operator can confirm that the first motor 31 or the second motor 32 has a failure by looking at the display. For this reason, it is possible to prevent the user from forgetting to repair or maintain the failed motor.

  Further, the display device 49 displays the correlation between the working radius of the lifting capacity database before updating and the setting lifting capacity value and the working radius and setting lifting capacity value of the lifting capacity database after updating in the comparison display section 82 of the update notification screen. Side by side with the correlation of For this reason, the operator can see the display on the comparison display unit 82 to know how much the set suspension capacity value after the update has decreased from the set suspension capacity value before the update. Then, the operator can select to suspend the load 100 with a load that does not exceed the updated set suspension capacity value in the lifting operation by the crane.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the description of the embodiments described above but by the claims, and includes all the modifications within the meaning and scope equivalent to the claims.

  For example, three or more motors may be provided to output a drive torque for rotating the drum.

  Moreover, the notification part by this invention is not necessarily limited to the display apparatus which alert | reports that the setting suspension capability value memorize | stored in the memory | storage part was updated by screen display. For example, a device for informing by voice, a lamp for informing by lighting or blinking, and other devices can be adopted as the informing unit according to the present invention.

  Further, the identification unit according to the present invention may not necessarily be incorporated in the display device. That is, the specification unit may be provided separately from the display device.

  Further, the specifying unit according to the present invention determines whether the operator of the crane is in the normal state or in the failure state as in the above embodiment, and operates the selecting portion if the state is the failure state. It is not necessarily limited to what specifies the state of the motor as a failure state.

  For example, the identification unit has a function of automatically determining whether the state of the motor is normal or not, and identifies the failed motor among the plurality of motors without depending on the operator's judgment. It may be

  Specifically, as in the system configuration of the first modified example shown in FIG. 7, the specifying unit 46 automatically determines whether the state of the motor 26 is the normal state or the failure state instead of the selecting unit 76. The determination unit 83 may be included in the determination.

  The determination unit 83 monitors the actual output and maximum torque of the first and second motors 31 and 32. Then, does the determination unit 83 detect that the actual output of each of the motors 31 and 32 is lower than the output of the corresponding specification and the difference between the actual output and the output of the specification exceeds a predetermined threshold value? Or when it is detected that the actual maximum torque of each motor 31, 32 is lower than the maximum torque of the corresponding specification and the difference between the actual maximum torque and the maximum torque of the specification exceeds a predetermined threshold value It is determined that the motors 31, 32 are in a failure state. On the other hand, determination unit 83 does not decrease the actual outputs of motors 31 and 32 until the difference between the actual output of each motor 31 and 32 and the output of the corresponding specification becomes equal to or greater than a predetermined threshold, When it is detected that the actual maximum torques of the motors 31, 32 have not decreased until the difference between the actual maximum torques of the motors 31, 32 and the maximum torque of the corresponding specification becomes equal to or greater than a predetermined threshold value. It is determined that the motors 31, 32 are in a normal state without failure. That is, in the above-described embodiment, the determination unit 83 automatically performs the determination that was performed when the operator identified the failed motor 26 in the above embodiment.

  Then, in the first modification, when the determination unit 83 determines that the first motor 31 is in the failure state, the signal output unit 77 determines that the first motor 31 is in the failure state accordingly. Is outputted to the overload prevention device 48. Further, when the signal output unit 77 determines that the first motor 31 is in a normal state in which the first motor 31 is not broken, a signal indicating that the first motor 31 is in a normal state is accordingly prevented from overloading. Output to the device 48. Further, the signal output unit 77 similarly outputs a signal indicating that the second motor 32 is in a failure state or a normal state to the overload prevention device 48 according to the determination of the determination unit 83 also for the second motor 32. Do. In the overload prevention device 48, the same processing as that of the above embodiment is performed.

  Further, in the first modification, the display device 49 displays the first and second electric motors 31 in the status display column 80 of the update notification screen (see FIG. 5) of the set suspension capacity value according to the determination of the determination unit 83. It automatically displays 32 states (normal state or failure state). Further, the display device 49 displays that the update has been performed in the same manner as in the above embodiment in response to the setting suspension capacity value of the suspension capacity database being updated, and the suspension capacity database before the update. The correlation between the working radius and the set suspension capacity value and the correlation between the work radius of the suspension capacity database after update and the set suspension capacity value are compared and displayed.

  According to the first modification, even if the operator does not determine whether or not the motor 26 breaks down, the motor 26 in the broken down state is automatically specified and the set suspension capacity value of the suspension capacity database is automatically set. Is updated so that the operator can concentrate on the operation of the crane for the lifting operation.

  Then, in response to the setting suspension capacity value of the suspension capacity database being updated, the display device 49 updates the setting suspension capacity value of the suspension capacity database in the update information display column 81 of the update notification screen of the setting suspension capacity value. Display what happened. For this reason, the operator can see that display to know that the set suspension capacity value has been updated.

  Further, as in the above embodiment, the display of the comparison display unit 82 of the update notification screen allows the operator to know how much the set suspension capacity value after the update has decreased from the set suspension capacity value before the update. .

  Further, in response to the setting suspension capacity value of the suspension capacity database being updated, the display device 49 displays the state (normal state or failure state) of each of the motors 31 and 32 in the state display column 80 of the update notification screen. . For this reason, the operator can recognize that the failure has occurred in the first motor 31 or the second motor 32 from the display. For this reason, it is possible to prevent the user from forgetting to repair or maintain the failed motor.

  Further, as a second modification, even when the malfunctioning motor 26 is specified by the specifying unit 46, the setting suspension capability value of the suspension capability database stored in the storage unit 56 is updated unless the operator permits the update. May not be performed. The system configuration of the crane according to this second modification is shown in FIG.

  In this second modification, the crane includes a permission device 84 used by the operator to allow the updating unit 60 to update the set suspension capacity value. The permission apparatus 84 updates the setting suspension capacity value in the updating unit 60 in response to the permission input unit 85 for inputting the instruction for permitting the update of the setting suspension capacity value and the instruction in the permission input unit 85. And an update permission unit 86 for giving permission.

  The permission input unit 85 is, for example, a switch or the like operated by the operator for permitting the update of the set suspension capacity value. The operation of the switch by the operator corresponds to the input of an instruction for permitting the update.

  The update permission unit 86 sends a permission signal indicating permission of update to the overload preventing device 48 in response to the instruction of permission of update being input to the permission input unit 85. The transmission of the permission signal corresponds to giving the updating unit 60 permission to update the set suspension capacity value.

  Then, the updating unit 60 responds to the fact that the broken motor 26 is specified by the specifying unit 46 and the update permission unit 86 gives permission for updating (a permission signal is input to the overload prevention device 48). And updating the setting suspension capability value of the suspension capability database stored in the storage unit 56.

  FIG. 9 shows a flowchart of a processing process performed when a failure occurs in the motor 26 in the second modification.

  Specifically, the processing process of the second modified example corresponds to the processing of the above embodiment with the processing of step S10 and step S11 added.

  Specifically, in the second modified example, after the operation of the motor 26 whose control unit 63 has failed in step S2 is stopped, the control unit 63 permits the permission input unit 85 to update the setting suspension capacity value in step S10. It is determined whether an instruction to do has been input. Specifically, the control unit 63 determines whether the permission signal is input from the update permission unit 86 to the overload prevention device 48 or not.

If the control unit 63 determines in step S10 that the permission input unit 85 receives an instruction to permit updating of the setting suspension capacity value, that is, if the permission signal is input to the overload prevention device 48, the following occurs. Then, the calculation of the maximum load w _x by the maximum load calculation unit 58 in step S3 is performed. Thereafter, the process related to the update of the setting suspension capacity value of the suspension capacity database stored in the storage unit 56 is performed.

  On the other hand, in step S10, the control unit 63 determines that the permission input unit 85 does not receive an instruction to permit updating of the setting suspension capacity value, that is, the permission signal is not input to the overload prevention device 48. In the case, next, the process of step S11 by the updating unit 60 is performed.

In step S11, the updating unit 60 sets the setting suspension capability value w ₀ corresponding to all the work radii r ₀ , r ₁ , r ₂ , r ₃ ,... Of the suspension capability database stored in the storage unit 56. Change w ₁ , w ₂ , w ₃ , ... to 0. After this step S11, the processing for updating the setting suspension capacity value of the suspension capacity database is ended.

In the second modification, even if the motor 26 in the failure state is specified, it is stored in the storage unit 56 unless the operator inputs an instruction for permitting the update of the setting suspension capacity value to the permission input unit 85. The set suspension capacity value of the suspension database is not updated to a value equal to the maximum load w _x that can be wound up by the drum 24 by the driving torque output from the motor 26 in the normal state without failure. That is, when the motor 26 in the failure state is specified, the operator can permit to change the setting suspension capacity value of the suspension capacity database to a value equal to the maximum load w _x by its own will. For this reason, the operator can reliably recognize that the set suspension capacity value has been changed to a value equal to the maximum load w _x .

  Further, in the second modification, when the operator does not input an instruction for permitting the update of the setting suspension capacity value to the permission input unit 85 after the motor 26 in the failure state is specified, the memory unit 56 stores the instruction. Since the setting suspension capacity value corresponding to all the working radiuses of the suspended capacity database is changed to 0, the motor 26 in the normal state which continues to operate without being specified as a failure state by the specifying unit 46 is also the control unit Stopped by 63. For this reason, even when the operator forgets to input an instruction to permit updating of the set suspension capacity value, overload can be reliably prevented.

  In the present invention, as shown in FIG. 2, for example, all of the plurality of motors for outputting the driving torque for rotating the drum are disposed on only one side of the drum in the axial direction of the drum which is the direction in which the central axis of the drum extends. However, the present invention is not necessarily limited to the arrangement of a plurality of motors. That is, the motor may be separately disposed on one side and the other side of the drum in the axial direction of the drum. FIGS. 10 and 11 show a hoisting winch having a plurality of motors so arranged.

  In particular, FIG. 10 shows a winding winch 15 according to a third variant with three motors 26. The three electric motors 26 include a first electric motor 31, a second electric motor 32 and a third electric motor 51. The first electric motor 31 and the second electric motor 32 are disposed on one side of the drum 24 in the axial direction of the drum 24 which is a direction in which the central axis of the drum 24 extends. The third motor 51 is disposed on the opposite side of the drum 24 to the first motor 31 and the second motor 32 in the axial direction of the drum 24. The first, second and third electric motors 31, 32, and 51 are operated by being supplied with electric power from the power supply 29, and respectively output driving torque for rotating the drum 24.

  In the winding winch 15 according to the third modification, the drum 24 extends in the axial direction of the drum 24 to the first rotation shaft 24 a, and in the axial direction of the drum 24 to the opposite side to the first rotation shaft 24 a And an extending second rotation shaft 24b. Also, the hoisting winch 15 has a torque transmission device 28, a first mechanical brake 33, a second mechanical brake 34 and a third mechanical brake 52. The torque transmission device 28 is connected to the first rotation shaft 24 a of the drum 24. The configuration related to the first electric motor 31, the second electric motor 32, the torque transmission device 28, the first mechanical brake 33 and the second mechanical brake 34 in the winding winch 15 of the third modification is the same as the winding winch 15 of the above embodiment. The configuration is the same as the configuration relating to the first electric motor 31, the second electric motor 32, the torque transmission device 28, the first mechanical brake 33, and the second mechanical brake 34 in the above.

  The third motor 51 has a drive shaft 51 a connected to the second rotation shaft 24 b of the drum 24. The third motor 51 is operated by the supply of electric power to rotate the drive shaft 51a. Thus, the driving torque output from the third electric motor 51 is input to the drum 24. The third mechanical brake 52 is attached to the third electric motor 51. The configuration according to the third mechanical brake 52 is the same as the configuration according to the first mechanical brake 33.

  A first switch 36 is provided on the electrical path supplying power from the power source 29 to the first motor 31, and a second switch 37 is provided on the electrical path supplying power from the power source 29 to the second motor 32. In addition, a third switch 91 is provided in an electric path for supplying power from the power source 29 to the third motor 51. The configuration related to the first switch 36 and the second switch 37 in the third modification is the same as the configuration related to the first switch 36 and the second switch 37 in the above embodiment. The third switch 91 electrically connects the power supply 29 and the third motor 51 to allow supply of power from the power supply 29 to the third motor 51, and allows conduction between the power supply 29 and the third motor 51. It switches to the OFF state which shuts off and stops the supply of the electric power from the power supply 29 to the 3rd electric motor 51. As shown in FIG.

  In the third modification, a failed motor among the first motor 31, the second motor 32, and the third motor 51 is specified in the same manner as the above example. The control of the third mechanical brake 52 is performed in the same manner as the control of the first mechanical brake 33 in the above embodiment, and the control of the third switch 91 is in the same manner as the control of the first switch 91 in the above embodiment. It will be. Further, in the third modified example, in the display device, in addition to the first and second motors 31 and 32, the display of the output and the maximum torque as the specifications, the current actual output and the maximum are also provided for the third motor 51. A display of torque and a display of normal state or failure state are performed.

  Further, FIG. 11 shows a winding winch 15 according to a fourth modification having four motors 26. The four electric motors 26 include a first electric motor 31, a second electric motor 32, a third electric motor 51, and a fourth electric motor 54. The first motor 31 and the second motor 32 are disposed on one side of the drum 24 in the axial direction of the drum 24. The third motor 51 and the fourth motor 54 are disposed on the opposite side of the drum 24 to the first motor 31 and the second motor 32 in the axial direction of the drum 24. The first, second, third, and fourth electric motors 31, 32, 51, 54 are operated by being supplied with electric power from the power source 29, and respectively output driving torque for rotating the drum 24.

  In the fourth modification, as in the case of the third modification, the drum 24 has a first rotation shaft 24 a and a second rotation shaft 24 b. In addition, the winding winch 15 according to the fourth modification includes the first torque transmission device 90, the second torque transmission device 93, the first mechanical brake 33, the second mechanical brake 34, the third mechanical brake 52, and the fourth mechanical brake. Have 55. The configuration according to the first electric motor 31, the second electric motor 32, the first torque transmission device 90, the first mechanical brake 33, and the second mechanical brake 34 in the winding winch 15 of the fourth modification is the same as the winding of the above embodiment. The configuration is the same as that of the first electric motor 31, the second electric motor 32, the torque transmission device 28, the first mechanical brake 33 and the second mechanical brake 34 in the winch 15.

  The third motor 51 has a drive shaft 51 a connected to the second torque transmission device 93. The fourth motor 54 has a drive shaft 54 a connected to the second torque transmission device 93. The third electric motor 51 is operated by supplying electric power to rotate the drive shaft 51a, and the fourth electric motor 54 is operated by supplying electric power to rotate the drive shaft 54a.

  The second torque transmission device 93 is connected to the second rotation shaft 24 b of the drum 24. The second torque transfer device 93 combines the drive torque input from the drive shaft 51 a of the third motor 51 and the drive torque input from the drive shaft 54 a of the fourth motor 54, and combines the combined drive torque with the drum 24. Of the second rotation shaft 24b.

  The third electric motor 51, the fourth electric motor 54, the second torque transmission device 93, the third mechanical brake 52 and the fourth mechanical brake 55 sandwich the drum 24, and the first electric motor 31, the second electric motor 32, the first torque transmission device 90, the first mechanical brake 33 and the second mechanical brake 34 are disposed symmetrically. The configurations related to the third electric motor 51, the fourth electric motor 54, the second torque transmission device 93, the third mechanical brake 52, and the fourth mechanical brake 55 other than this arrangement are the first electric motor 31, the second electric motor 32, and the torque transmission device The configuration is the same as that of the first mechanical brake 33 and the second mechanical brake 34.

  A first switch 36 is provided on the electrical path supplying power from the power source 29 to the first motor 31, and a second switch 37 is provided on the electrical path supplying power from the power source 29 to the second motor 32. In addition, the third switch 91 is provided in the electric path supplying power from the power source 29 to the third motor 51, and the fourth switch 92 is provided in the electric path supplying power from the power source 29 to the fourth motor 54. It is done. The configuration related to the first switch 36 and the second switch 37 in the fourth modification is the same as the configuration related to the first switch 36 and the second switch 37 in the above embodiment. The configuration according to the third switch 91 is the same as the configuration of the third switch 91 in the third modification. Further, the fourth switch 92 electrically connects the power supply 29 and the fourth motor 54 to allow the supply of power to the power supply 29 and the fourth motor 54, and between the power supply 29 and the fourth motor 54. It switches to the OFF state which interrupts conduction | electrical_connection and stops supply of the electric power from the power supply 29 to the 4th electric motor 54. FIG.

  In the fourth modification, out of the first motor 31, the second motor 32, the third motor 51, and the fourth motor 54, a failed motor is specified in the same manner as the above example. Further, the control of the first mechanical brake 33 and the second mechanical brake 34 similar to the above embodiment is performed, and the first mechanical brake 33 and the second mechanical brake 34 are also controlled for the third mechanical brake 52 and the fourth mechanical brake 55. Control similar to the control of is performed. Further, the control of the first switch 36 and the second switch 37 similar to those of the above embodiment is performed, and the control similar to the first switch 36 and the second switch 37 is performed for the third switch 91 and the fourth switch 92 as well. It will be. Further, in the fourth modified example, regarding the first, second, third and fourth electric motors 31, 32, 51 and 54 in the display device, the display of the output as the specification and the maximum torque, and the current actual output And the indication of the maximum torque and the indication of the normal state or the failure state are performed respectively.

24 winch drum 26 motor 31 first motor 32 second motor 44 load detector (load lead out part)
46 Identification unit 48 Overload prevention device 49 Display device (notification unit)
56 storage unit 58 maximum load calculation unit 60 update unit 63 control unit 85 permission input unit 86 update permission unit 101 object

Claims (4)

A crane that raises or lowers an object,
A winch drum which rotates to wind up or down the object;
A plurality of motors, each of which outputs a driving torque that is activated by the supply of power to rotate the winch drum;
A load deriving unit that derives the value of the load of the object applied to the winch drum;
The value of the load derived by the load deriving unit is monitored, and when the value of the load exceeds the set suspension capacity value of the crane, the operation of each of the plurality of motors is stopped to rotate the winch drum. Overload prevention device to stop the
And a specification unit that specifies a failed motor among the plurality of motors.
The overload prevention device can wind up the winch drum by a storage unit storing the set suspension capacity value, and driving torques output from the remaining motors other than the failed motor identified by the identification unit. A maximum load calculating unit that calculates a maximum load; an updating unit that updates the set suspension capacity value stored in the storage unit to a value equal to the maximum load calculated by the maximum load calculating unit; And a control unit that controls a plurality of motors,
The control unit stops the operation of the failed motor specified by the specifying unit, and the latest set suspension capacity value in which the value of the load derived by the load deriving unit is stored in the storage unit The control is performed to operate the remaining electric motors if the following is the case, and to stop the operation of the plurality of electric motors when the value of the load derived by the load deriving unit exceeds the latest set suspension capacity value Do the crane.   The system further comprises a notification unit that notifies the operator of the crane that the set suspension capacity value has been updated in response to the update unit updating the set suspension capacity value stored in the storage unit. The crane of item 1.   The crane according to claim 2, wherein the notification unit is a display device that displays the updated setting suspension capacity value. A permission input unit for inputting an instruction for permitting update of the set suspension capacity value;
It further comprises: an update permitting unit which gives the updating unit permission to update the set suspension capacity value in response to the instruction being input to the permission input unit;
4. The apparatus according to claim 1, wherein the updating unit updates the set suspension capacity value in response to a specification of the failed motor by the specifying unit and permission of the update being given by the update permission unit. The crane according to any one of the preceding claims.

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