WO2021085569A1 - Overload prevention device - Google Patents

Overload prevention device Download PDF

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Publication number
WO2021085569A1
WO2021085569A1 PCT/JP2020/040715 JP2020040715W WO2021085569A1 WO 2021085569 A1 WO2021085569 A1 WO 2021085569A1 JP 2020040715 W JP2020040715 W JP 2020040715W WO 2021085569 A1 WO2021085569 A1 WO 2021085569A1
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WO
WIPO (PCT)
Prior art keywords
moment
boom
crane
overload
overload prevention
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PCT/JP2020/040715
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French (fr)
Japanese (ja)
Inventor
正裕 石井
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株式会社タダノ
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Publication date
Application filed by 株式会社タダノ filed Critical 株式会社タダノ
Priority to JP2021553702A priority Critical patent/JP7088418B2/en
Publication of WO2021085569A1 publication Critical patent/WO2021085569A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
    • B66C23/88—Safety gear
    • B66C23/90—Devices for indicating or limiting lifting moment

Definitions

  • the present invention relates to an overload prevention device for a crane. More specifically, the present invention relates to an overload prevention device for preventing a fall due to an overload of a crane.
  • the overload prevention device determines that the outrigger jack is overloaded when the ground contact reaction force of the outrigger jack becomes equal to or less than the threshold value.
  • the outrigger jack In the case of a loaded truck crane, the outrigger jack is installed almost right next to the turning center of the boom. In such a configuration, the ground reaction force of the outrigger jack does not change even if the forward overturning moment increases. Therefore, it is not possible to detect a forward fall based on the ground contact reaction force of the outrigger jack.
  • Patent Document 1 discloses a technique for detecting a forward fall based on the fact that the actual load reaches the allowable forward lifting load.
  • the permissible forward lifting load is obtained from the forward overturning moment at the limit where the rear wheels of the truck are lifted in the boom front work in which the telescopic boom is swiveled to the front of the truck in an empty state where no load is loaded on the truck bed.
  • Patent Document 1 The permissible forward lifting load of Patent Document 1 is obtained from the forward overturning moment in the state where the boom is most likely to overturn toward the front. Therefore, when the boom is directed diagonally forward, the loaded truck crane will not tip over even if the actual load exceeds the allowable forward lifting load to some extent. In other words, when the boom is directed diagonally forward, the operation of the crane device is restricted even though there is room for a fall. This means that the working range in front of the crane equipment is unnecessarily limited.
  • an object of the present invention is to provide a crane overload prevention device capable of expanding the working range in front of the crane.
  • An overload prevention device that has a boom and is built into a crane that transports suspended loads.
  • An acquisition unit that acquires a tipping moment that is a moment acting on the boom based on the load of the suspended load and includes a forward moment and a lateral moment as components.
  • a control unit that performs overload prevention control including control of either stopping the boom operation or issuing an alarm when the forward moment included in the overturning moment is larger than the first threshold value. Be prepared.
  • An overload prevention device that has a boom and is built into a crane that transports suspended loads.
  • An acquisition unit that acquires a tipping moment that is a moment acting on the boom based on the load of the suspended load and includes a forward moment and a lateral moment as components.
  • the first determination unit that determines whether the crane is in an overloaded state with respect to the front
  • the second judgment unit that determines whether the crane is overloaded with respect to the side
  • a third judgment unit that determines whether the crane is overloaded with respect to strength
  • the overload is determined based on the forward overturning component of the overturning moment acting on the boom, the working range when the boom is directed diagonally forward can be expanded.
  • FIG. 1 is a side view of a loaded truck crane.
  • FIG. 2 is a plan view of a loaded truck crane.
  • FIG. 3 is a hydraulic circuit diagram of a small crane.
  • FIG. 4 is an explanatory view of the forward working range.
  • FIG. 5 is a block diagram of the overload prevention device according to the first embodiment.
  • FIG. 6 is a flowchart of control of the forward stability monitoring unit according to the first embodiment.
  • FIG. 7 is a flowchart of control of the forward stability monitoring unit according to the second embodiment.
  • the overload prevention device AA according to the first embodiment of the present invention is used to prevent the mobile crane from tipping over due to overload.
  • mobile cranes include all-terrain cranes, rough terrain cranes, truck cranes, and loaded truck cranes.
  • the overload prevention device AA of the present embodiment is preferably used for a load-type truck crane.
  • the load-type truck crane CR has a general-purpose truck 10.
  • a driver's cab 11 is provided in the front portion of the general-purpose truck 10, and a loading platform 12 is provided in the rear portion.
  • a small crane 20 is mounted in a portion of the vehicle frame 13 of the general-purpose truck 10 between the driver's cab 11 and the loading platform 12.
  • the small crane 20 has a base 21 fixed on the vehicle frame 13.
  • a post 22 is provided on the base 21 so as to be rotatable.
  • a boom 23 is provided on the upper end of the post 22 so as to be undulating.
  • the post 22 has a built-in winch.
  • the wire rope extended from this winch is guided to the tip of the boom 23.
  • the wire rope is hung around a pulley provided at the tip of the boom 23 and the hook 24. As a result, the hook 24 is suspended from the tip of the boom 23.
  • a suspended load is suspended from the hook 24.
  • a device composed of a post 22, a boom 23, a hook 24, etc. and used for transporting a suspended load is referred to as a "crane device".
  • the boom 23 can be expanded and contracted and undulated, and can be swiveled around the swivel center O.
  • the length of the boom 23 is referred to as L.
  • the undulation angle (angle with respect to the horizontal plane) of the boom 23 is expressed as ⁇ .
  • the turning angle of the boom 23 is referred to as ⁇ .
  • the turning angle ⁇ is 0 ° directly in front of the loaded truck crane CR.
  • the small crane 20 has an outrigger jack 25 in addition to the crane device.
  • the outrigger jacks 25 are arranged on the left and right sides of the small crane 20.
  • the left and right outrigger jacks 25 and the turning center O of the boom 23 are arranged side by side in the vehicle width direction. That is, the left and right outrigger jacks 25 and the turning center O of the boom 23 are arranged at the same position in the front-rear direction of the general-purpose truck 10 or are arranged at short distances.
  • An outrigger jack different from the outrigger jack 25 may be provided on the left and right rear of the loading platform 12.
  • the small crane 20 is hydraulically driven by the hydraulic circuit 30 shown in FIG.
  • the hydraulic circuit 30 has a hydraulic valve unit 31.
  • the inlet port of the hydraulic valve unit 31 is connected to the tank 32 via the main oil passage 34.
  • a hydraulic pump 33 is provided in the main oil passage 34.
  • the hydraulic pump 33 is connected to the engine 14 of the general-purpose truck 10 via a PTO (power take-off) device, and is driven by the engine 14.
  • the hydraulic oil in the tank 32 is supplied to the hydraulic valve unit 31 by the hydraulic pump 33.
  • the outlet port of the hydraulic valve unit 31 is connected to the tank 32 via the return oil passage 35.
  • a plurality of hydraulic actuators 36a to 36f are connected to the hydraulic valve unit 31.
  • the hydraulic actuators 36a to 36f are a boom expansion / contraction hydraulic cylinder 36a, a winch hydraulic motor 36b, a boom undulating hydraulic cylinder 36c, a swivel hydraulic motor 36d, and an outrigger hydraulic cylinders 36e and 36f.
  • the boom 23 expands and contracts due to the operation of the boom expansion and contraction hydraulic cylinder 36a.
  • the hook 24 is wound up and down by the operation of the winch hydraulic motor 36b.
  • the boom 23 undulates due to the operation of the boom undulating hydraulic cylinder 36c.
  • the post 22 is swiveled by the operation of the swivel hydraulic motor 36d.
  • the outrigger jacks 25 and 25 expand and contract by the operation of the outrigger hydraulic cylinders 36e and 36f.
  • the hydraulic valve unit 31 is provided with a telescopic switching control valve 37a, a winch switching control valve 37b, an undulating switching control valve 37c, a swivel switching control valve 37d, and outrigger switching control valves 37e and 37f.
  • a boom expansion / contraction hydraulic cylinder 36a is connected to the expansion / contraction switching control valve 37a.
  • a winch hydraulic motor 36b is connected to the winch switching control valve 37b.
  • a boom undulating hydraulic cylinder 36c is connected to the undulating switching control valve 37c.
  • a swivel hydraulic motor 36d is connected to the swivel switching control valve 37d.
  • the outrigger hydraulic cylinders 36e and 36f are connected to the outrigger switching control valves 37e and 37f, respectively.
  • the switching control valves 37a to 37f control the direction and flow rate of the hydraulic oil supplied from the hydraulic pump 33 to control the operation of the hydraulic actuators 36a to 36f.
  • An operation lever is connected to the spools of the switching control valves 37a to 37f via a link mechanism or the like.
  • the spool positions of the switching control valves 37a to 37f can be switched. That is, the switching control valves 37a to 37f can be directly operated by the operating lever.
  • the small crane 20 has an operating lever group 26.
  • the operating levers constituting the operating lever group 26 are connected to any of the switching control valves 37a to 37f. The operator can operate the small crane 20 by using the operating lever group 26.
  • pilot cylinders 38a to 38f are attached to the spools of the switching control valves 37a to 37f, respectively.
  • the spool positions of the switching control valves 37a to 37f can also be switched by the operation of the pilot cylinders 38a to 38f.
  • Each of the pilot cylinders 38a to 38f is a double-acting cylinder, and is provided with a solenoid valve for supplying and discharging hydraulic oil to the right oil chamber and an electromagnetic valve for supplying and discharging hydraulic oil to the left oil chamber. There is. These solenoid valves are connected to the control device 40.
  • the control device 40 is a computer composed of a CPU, a memory, and the like. By operating the solenoid valve based on the control signal from the control device 40, the pilot cylinders 38a to 38f are driven, and the spool positions of the switching control valves 37a to 37f are switched. In this way, the control device 40 controls the operation of the small crane 20.
  • the control device 40 can perform bidirectional wireless communication or wired communication with the remote control terminal 41.
  • the remote control terminal 41 may be a wireless control terminal such as a so-called radio control transmitter, or a wired control terminal.
  • the remote control terminal 41 is equipped with an input unit including various switches and an accelerator trigger.
  • the remote control terminal 41 transmits an operation signal to the control device 40.
  • the control device 40 controls the hydraulic circuit 30 based on the operation signal to operate the small crane 20. In this way, the operator can remotely control the small crane 20 using the remote control terminal 41.
  • the small crane 20 has an attitude measuring device that measures the attitude of the boom 23.
  • the posture of the boom 23 is represented by the length L of the boom 23, the undulation angle ⁇ , and the turning angle ⁇ .
  • the posture measuring instrument consists of a plurality of measuring instruments that measure each of these parameters L, ⁇ , and ⁇ . That is, the posture measuring device includes a length measuring device 42, an undulation angle measuring device 43, and a turning angle measuring device 44.
  • the length measuring device 42 measures the length L of the boom 23.
  • the configuration of the length measuring instrument 42 is not particularly limited, and examples thereof include a configuration in which the rotation angle of the cord reel in which the end of the cord is fixed to the tip of the boom 23 is read by a potentiometer.
  • the undulation angle measuring device 43 measures the undulation angle ⁇ of the boom 23.
  • the configuration of the undulation angle measuring device 43 is not particularly limited, and examples thereof include a configuration in which a pendulum type angle measuring device in which a pendulum is attached to a potentiometer is provided on the boom 23.
  • the turning angle measuring device 44 measures the turning angle ⁇ of the boom 23.
  • the configuration of the swivel angle measuring device 44 is not particularly limited, but in addition to a configuration in which the swivel angle ⁇ of the boom 23 is discretely detected by a plurality of proximity switches provided on the base 21 or the post 22, a hydraulic motor that swivels the post 22
  • An example is a configuration in which the rotation angle is read by a potentiometer.
  • the small crane 20 has a moment measuring device 45 for measuring the overturning moment M acting on the boom 23.
  • the moment measuring device 45 corresponds to an example of the acquisition unit.
  • the overturning moment M is generated by the load of the suspended load and the own weight of the boom 23.
  • the configuration of the moment measuring device 45 is not particularly limited, and examples thereof include a configuration in which the oil pressure in the boom undulating hydraulic cylinder 36c that undulates the boom 23 is measured by a pressure sensor.
  • the control device 40 has a function as an overload prevention device AA in addition to a function of controlling the operation of the small crane 20.
  • the overload prevention device AA may be configured by a computer different from the control device 40.
  • the measurement values of the posture measuring device (length measuring device 42, undulation angle measuring device 43, turning angle measuring device 44) and the moment measuring device 45 are input to the overload prevention device AA. .. That is, the overload prevention device AA is input with the measured values of the boom 23 length L d , the undulation angle ⁇ d, and the turning angle ⁇ d , and the measured values of the overturning moment M d.
  • the overload prevention device AA detects the overload state of the small crane 20 based on these measured values L d , ⁇ d , ⁇ d , and M d.
  • the "overload state” is a state in which the overload moment exceeds the stable moment and the load-type truck crane CR overturns, and a state in which the load due to the load of the suspended load exceeds the load capacity of the constituent members of the small crane 20. , Or a state approaching those states.
  • the overload prevention device AA has a front stability monitoring unit 51, a side stability monitoring unit 52, and a strength limit monitoring unit 53.
  • the forward stability monitoring unit 51 corresponds to an example of the control unit and the first determination unit, and monitors whether or not the loaded truck crane CR falls forward, that is, the stability in the forward direction.
  • the lateral stability monitoring unit 52 corresponds to an example of the second determination unit and monitors whether or not the loaded truck crane CR falls sideways, that is, lateral stability.
  • the strength limit monitoring unit 53 corresponds to an example of the third determination unit, and monitors whether or not the load due to the load of the suspended load exceeds the withstand load of the constituent members.
  • the maximum value of the forward moment M f that ensures the forward stability of the loaded truck crane CR is defined as the forward rated moment M f-lim .
  • the forward rated moment M f-lim corresponds to an example of the first threshold value and is a predetermined value.
  • the front rated moment M f-lim means that, for example, the rear wheel of the general-purpose truck 10 is lifted when the boom 23 faces directly in front of the general-purpose truck 10 in an empty state where no load is loaded on the loading platform 12 and the general-purpose truck 10 is most likely to fall forward. It is set to the magnitude of the limit overturning moment.
  • the value obtained by multiplying the magnitude of the critical overturning moment by the safety factor (value less than 1) may be the forward rated moment M f-lim.
  • a predetermined ratio (for example, 25%) of the magnitude of the lateral stabilizing moment may be set as the forward rated moment M f-lim with reference to the lateral stabilizing moment of the loaded truck crane CR.
  • the forward rated moment M f-lim is set as the upper limit of the forward moment at which the loaded crane does not tip over forward.
  • the first threshold is preset as an upper limit of the load that prevents the crane from tipping forward.
  • the first threshold value is stored in the storage unit 60 in association with the turning angle that the boom 23 can take.
  • the forward moment M f By comparing the forward moment M f and the forward rated moment M f-lim , it can be determined whether or not the loaded truck crane CR falls forward. Specifically, when the forward moment M f is equal to or less than the forward rated moment M f-lim , it is determined that the vehicle does not tip forward. If the forward moment M f exceeds the forward rated moment M f-lim , it is determined that the vehicle falls forward (overload).
  • the work range R1 in front becomes a semi-circular region.
  • the front working range R2 is a horizontally long region including the working range R1. ..
  • the working range when the boom 23 is directed diagonally forward can be expanded.
  • the forward stability monitoring unit 51 of the present embodiment performs the following control.
  • the front stability monitoring unit 51 stores the front rated moment M f-lim in advance. Therefore, the forward stability monitoring unit 51 also has a function as a storage unit. As shown in FIG. 6, first, the forward stability monitoring unit 51 acquires the measured values ⁇ d and M d from the turning angle measuring device 44 and the moment measuring device 45 (step S11).
  • the forward stability monitoring unit 51 confirms that the boom 23 is arranged in the front region of the loaded truck crane CR (step S12).
  • the fact that the boom 23 is arranged in the front region means that the tip end portion (hook 24) of the boom 23 is arranged in front of the forward tipping baseline.
  • the forward overturning baseline is, for example, a line connecting the grounding positions of the left and right outrigger jacks 25.
  • the boom 23 is arranged in the front region when the turning angle ⁇ d of the boom 23 is within the range of ⁇ 90 ° to + 90 °. You can judge that there is.
  • the state in which the boom 23 is arranged in the front region means a state in which the magnitude of the forward moment acting on the boom 23 is greater than 0 based on the load W of the suspended load.
  • the process ends. On the other hand, when the boom 23 is arranged in the front region, the process is continued.
  • the forward stability monitoring unit 51 obtains the forward overturning component of the overturning moment M, that is, the forward moment M f from the measured values ⁇ d and M d of the turning angle and the overturning moment according to the equation (2) (step S13). ..
  • the overturning moment has a forward moment M f and a lateral moment as components.
  • the forward moment M f of the overturning moment becomes the maximum, and the turning angle of the boom 23 is 90 ° or ⁇ 90 °.
  • the forward moment M f of the overturning moment becomes the minimum.
  • the forward moment is a moment acting on the boom 23, and means a moment around an axis parallel to the left-right direction of the loaded truck crane CR.
  • the lateral moment is a moment acting on the boom 23, and means a moment around an axis parallel to the front-rear direction of the loaded truck crane CR.
  • the forward stability monitoring unit 51 compares the forward moment M f with the forward rated moment M f-lim (step S14). Then, when the forward moment M f exceeds the forward rated moment M f-lim , it is determined that the load is overloaded (step S15). Further, the forward stability monitoring unit 51 implements overload prevention control including at least one of control of stopping the operation of the boom 23 and control of issuing an alarm when it is determined that the load is overloaded.
  • the overload prevention control may include a control other than a control for stopping the operation of the boom 23 and a control for issuing an alarm.
  • the lateral stability monitoring unit 52 determines that the load is overloaded when the load-type truck crane CR falls under the condition of falling sideways, or when such a condition is approached.
  • the specific control of the lateral stability monitoring unit 52 is not particularly limited, but for example, the following control is performed.
  • the load-type truck crane CR has a ground reaction force measuring device 46 that measures the ground reaction force F of the left and right outrigger jacks 25.
  • the configuration of the ground reaction force measuring device 46 is not particularly limited, and examples thereof include a configuration using a hydraulic sensor that measures the oil pressure in the oil chamber of the outrigger jack 25.
  • the ground contact reaction force F can be calculated from the differential pressure between the holding side oil chamber and the non-holding side oil chamber of the outrigger jack 25 and the pressure receiving area of the jack cylinder.
  • the measurement values of the ground reaction force measuring device 46 i.e., the ground reaction force F d outrigger jacks 25 are input to the overload prevention device AA.
  • the lateral stability monitoring unit 52 determines that the load is overloaded when the ground contact reaction force F d of any of the left and right outrigger jacks 25 falls below the reaction force threshold value F lim.
  • the reaction force threshold value F lim is a value preset in the lateral stability monitoring unit 52.
  • the reaction force threshold value F lim may be a fixed value of 1, or may be variable based on the postures L, ⁇ , ⁇ of the boom 23, the load of the suspended load, the overhang width of the outrigger jack 25, and the like.
  • the lateral stability monitoring unit 52 performs lateral stability monitoring at least when the boom 23 is arranged in the lateral region.
  • the fact that the boom 23 is arranged in the lateral region means that the tip end portion (hook 24) of the boom 23 is arranged laterally from the lateral tipping baseline.
  • the front area and the side area of the boom 23 partially overlap each other diagonally in front of the loaded truck crane CR.
  • the side stability monitoring unit 52 may always perform lateral stability monitoring regardless of the turning angle ⁇ of the boom 23. Therefore, when the boom 23 is arranged in the front region, lateral stability monitoring is performed as well as forward stability monitoring. Even if the front stability monitoring unit 51 does not determine that it is overloaded, the side stability monitoring unit 52 may determine that it is overloaded.
  • the strength limit monitoring unit 53 determines that the load is overloaded when the load due to the load of the suspended load exceeds the withstand load of the constituent members.
  • the specific control of the strength limit monitoring unit 53 is not particularly limited, but for example, the following control is performed.
  • the strength rated moment M s-lim (L, ⁇ ) is stored in advance in the strength limit monitoring unit 53.
  • the strength rated moment M s-lim is a value determined for each length L of the boom 23 and an undulation angle ⁇ as a moment that a component member such as the boom 23 can withstand.
  • the length L and the undulation angle ⁇ of the boom 23 correspond to an example of the posture condition of the boom 23.
  • the strength rated moment M s-lim may be stored in a table format, or may be stored as a function with the length L of the boom 23 and the undulation angle ⁇ as variables.
  • the strength rated moment M s-lim may be a value determined for each of the length L of the boom 23, the undulation angle ⁇ , and the turning angle ⁇ . Further, the strength rated moment M s-lim may be a fixed value that does not depend on the length L of the boom 23 or the like.
  • the strength limit monitoring unit 53 acquires the measured values L d , ⁇ d , and M d from the length measuring device 42, the undulation angle measuring device 43, and the moment measuring device 45. Next, the strength limit monitoring unit 53 acquires the strength rated moment M s-lim (L d , ⁇ d ) corresponding to the measured values L d and ⁇ d of the length and undulation angle of the boom 23. Then, the strength limit monitoring unit 53 compares the overturning moment M d with the strength rated moment M s-lim (L d , ⁇ d). Then, when the overturning moment M d exceeds the strength rated moment M s-lim (L d , ⁇ d ), it is determined that the load is overloaded.
  • the strength limit monitoring unit 53 constantly monitors the strength limit regardless of the turning angle ⁇ of the boom 23.
  • the overload prevention device AA has a final determination unit 54.
  • the determination results of the front stability monitoring unit 51, the side stability monitoring unit 52, and the strength limit monitoring unit 53 are input to the final determination unit 54.
  • the final determination unit 54 obtains the logical sum of the determination results of the front stability monitoring unit 51, the side stability monitoring unit 52, and the strength limit monitoring unit 53, and finally determines the overload. That is, when any one or more of the front stability monitoring unit 51, the side stability monitoring unit 52, and the strength limit monitoring unit 53 determines that the load is overloaded, the final determination unit 54 determines that the load is overloaded. On the contrary, when none of the front stability monitoring unit 51, the side stability monitoring unit 52, and the strength limit monitoring unit 53 determines that the load is overloaded, the final determination unit 54 determines that the load is not overloaded.
  • the determination result of the final determination unit 54 is output to the control device 40.
  • the control device 40 may automatically stop the operation of the boom 23 or issue an alarm.
  • the automatic stop is performed by stopping the operation of the boom 23 in the direction in which the overturning moment increases. That is, it stops the extension and lodging of the boom 23 and allows the boom 23 to contract and stand. Further, the winding of the hook 24 may be stopped and the winding of the hook 24 may be allowed. Either one of the automatic stop and the alarm may be performed, or both may be performed.
  • the overload prevention device AA according to the second embodiment of the present invention will be described.
  • the configuration of the overload prevention device AA of the present embodiment is the same as the configuration shown in FIG. Further, the control of the lateral stability monitoring unit 52, the strength limit monitoring unit 53, and the final determination unit 54 is the same as in the first embodiment. Therefore, only the control of the forward stability monitoring unit 51 will be described.
  • the forward stability monitoring unit 51 stores the overturning rated moment M lim ( ⁇ ) in advance.
  • the overturning rated moment M lim corresponds to an example of the second threshold value, and is the overturning moment M when the forward overturning component (forward moment M f ) of the overturning moment M acting on the boom 23 becomes the forward rated moment M f-lim. It is a value determined for each turning angle ⁇ of the boom 23 so as to be. That is, the second threshold value is set in association with the forward rated moment, which is the first threshold value.
  • the forward stability monitoring unit 51 may store the overturning rated moment M lim in a table format, or may store it as a function with the turning angle ⁇ of the boom 23 as a variable. Therefore, the forward stability monitoring unit 51 also has a function as a storage unit for storing the second threshold value.
  • the forward stability monitoring unit 51 acquires the measured values ⁇ d and M d from the turning angle measuring device 44 and the moment measuring device 45 (step S21).
  • the forward stability monitoring unit 51 confirms that the boom 23 is arranged in the front region of the loaded truck crane CR (step S22). If the boom 23 is not located in the front region, the process ends. On the other hand, when the boom 23 is arranged in the front region, the process is continued.
  • the forward stability monitoring unit 51 acquires the overturning rated moment M lim ( ⁇ d ) corresponding to the measured value ⁇ d of the turning angle of the boom 23 (step S23). Then, the forward stability monitoring unit 51 compares the measured value M d of the overturning moment with the overturning rated moment M lim ( ⁇ d ) (step S24). Then, when the overturning moment M d exceeds the overturning rated moment M lim ( ⁇ d ), it is determined that the load is overloaded (step S25).
  • the following overload prevention device can also be implemented as a reference example of the present invention.
  • the overload prevention device according to Reference Example 1 is An overload prevention device for mobile cranes with a boom. When the forward overturning component of the overturning moment acting on the boom exceeds a predetermined forward rated moment, it is determined to be an overload.
  • the overload prevention device according to Reference Example 2 is input with the measured value of the overturning moment acting on the boom and the measured value of the turning angle of the boom. You can. In this case, the overload prevention device obtains the forward overturning component of the overturning moment based on the measured values of the overturning moment and the turning angle. Then, the overload prevention device may determine that the overload is overloaded when the forward overturning component of the overturning moment exceeds the forward rated moment.
  • the overload prevention device according to Reference Example 3 is input with the measured value of the overturning moment acting on the boom and the measured value of the turning angle of the boom. You can. In this case, the overload prevention device stores the overturning rated moment determined for each turning angle of the boom so that it becomes the overturning moment when the forward overturning component of the overturning moment acting on the boom becomes the forward rated moment. May be good. Then, the overload prevention device may determine that the overload is overloaded when the measured value of the overload moment exceeds the overturn rated moment corresponding to the measured value of the turning angle of the boom.
  • the present invention is applicable not only to loaded truck cranes but also to various mobile cranes.

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Abstract

An overload prevention device according to the present invention is incorporated into a crane that has a boom and transports a hoisted load, said overload prevention device being provided with an acquisition unit and a control unit. The acquisition unit acquires an overturning movement, which is a moment that acts on the boom on the basis of the weight of a hoisted load and includes a forward moment and a lateral moment as components. When the forward moment included in the overturning moment is greater than a first threshold, the control unit implements overload prevention control that includes either control to stop the operation of the boom, or control to issue an alarm.

Description

過負荷防止装置Overload prevention device
　本発明は、クレーンの過負荷防止装置に関する。さらに詳しくは、本発明は、クレーンの過負荷による転倒を防止するための過負荷防止装置に関する。 The present invention relates to an overload prevention device for a crane. More specifically, the present invention relates to an overload prevention device for preventing a fall due to an overload of a crane.
　クレーンの過負荷防止装置として、アウトリガジャッキの接地反力に基づき、転倒を検知するものがある。移動式クレーンの転倒モーメントが大きくなると、それに従い反転倒側に設けられたアウトリガジャッキの接地反力が小さくなる。これを利用して、過負荷防止装置は、アウトリガジャッキの接地反力が閾値以下となったときに過負荷と判断する。 There is a crane overload prevention device that detects a fall based on the ground reaction force of the outrigger jack. As the overturning moment of the mobile crane increases, the ground contact reaction force of the outrigger jack provided on the overturning side decreases accordingly. Utilizing this, the overload prevention device determines that the outrigger jack is overloaded when the ground contact reaction force of the outrigger jack becomes equal to or less than the threshold value.
　積載形トラッククレーンの場合、アウトリガジャッキは、ブームの旋回中心のほぼ真横に設けられる。このような構成では、前方への転倒モーメントが大きくなってもアウトリガジャッキの接地反力は変化しない。そのため、アウトリガジャッキの接地反力に基づいて前方への転倒を検知することはできない。 In the case of a loaded truck crane, the outrigger jack is installed almost right next to the turning center of the boom. In such a configuration, the ground reaction force of the outrigger jack does not change even if the forward overturning moment increases. Therefore, it is not possible to detect a forward fall based on the ground contact reaction force of the outrigger jack.
　これに対して、特許文献１には、実荷重が許容前方吊上荷重に達したことに基づいて、前方への転倒を検知する技術が開示されている。許容前方吊上荷重は、トラックの荷台に荷物を積載しない空荷状態で伸縮ブームをトラック正面に旋回させたブーム正面作業においてトラックの後輪が浮き上がる限界の前方転倒モーメントから求められる。 On the other hand, Patent Document 1 discloses a technique for detecting a forward fall based on the fact that the actual load reaches the allowable forward lifting load. The permissible forward lifting load is obtained from the forward overturning moment at the limit where the rear wheels of the truck are lifted in the boom front work in which the telescopic boom is swiveled to the front of the truck in an empty state where no load is loaded on the truck bed.
特開２００８－１０５８１７号公報Japanese Unexamined Patent Publication No. 2008-105817
　特許文献１の許容前方吊上荷重は、ブームを真正面に向けた最も転倒しやすい状態における前方転倒モーメントから求められる。そのため、ブームを斜め前に向けた状態では、実荷重が許容前方吊上荷重をある程度超えたとしても、積載形トラッククレーンが前方に転倒することはない。言い換えれば、ブームを斜め前に向けた状態では、転倒に対する余裕があるにもかかわらず、クレーン装置の動作が制限される。これは、クレーン装置の前方の作業範囲が必要以上に制限されることを意味する。 The permissible forward lifting load of Patent Document 1 is obtained from the forward overturning moment in the state where the boom is most likely to overturn toward the front. Therefore, when the boom is directed diagonally forward, the loaded truck crane will not tip over even if the actual load exceeds the allowable forward lifting load to some extent. In other words, when the boom is directed diagonally forward, the operation of the crane device is restricted even though there is room for a fall. This means that the working range in front of the crane equipment is unnecessarily limited.
　本発明は上記事情に鑑み、前方の作業範囲を拡大できるクレーンの過負荷防止装置を提供することを目的とする。 In view of the above circumstances, an object of the present invention is to provide a crane overload prevention device capable of expanding the working range in front of the crane.
　　本発明に係る過負荷防止装置の一態様は、
　ブームを有し、吊荷を搬送するクレーンに組み込まれる過負荷防止装置であって、
　吊荷の荷重に基づいてブームに作用するモーメントであって、前方モーメント及び側方モーメントを成分として含む転倒モーメントを取得する取得部と、
　転倒モーメントに含まれる前方モーメントが、第一閾値よりも大きい場合に、ブームの動作を停止する制御及び警報を発する制御の何れか一方の制御を含む過負荷防止制御を実施する制御部と、を備える。 One aspect of the overload prevention device according to the present invention is
An overload prevention device that has a boom and is built into a crane that transports suspended loads.
An acquisition unit that acquires a tipping moment that is a moment acting on the boom based on the load of the suspended load and includes a forward moment and a lateral moment as components.
A control unit that performs overload prevention control including control of either stopping the boom operation or issuing an alarm when the forward moment included in the overturning moment is larger than the first threshold value. Be prepared.
　　本発明に係る過負荷防止装置の一態様は、
　ブームを有し、吊荷を搬送するクレーンに組み込まれる過負荷防止装置であって、
　吊荷の荷重に基づいてブームに作用するモーメントであって、前方モーメント及び側方モーメントを成分として含む転倒モーメントを取得する取得部と、
　前方モーメントに基づいて、クレーンが前方に関する過負荷状態であるか否かを判定する第一判定部と、
　クレーンが側方に関する過負荷状態であるか否かを判定する第二判定部と、
　クレーンが強度に関する過負荷状態であるか否かを判定する第三判定部と、
　第一判定部、第二判定部、及び第三判定部のうちの少なくとも一つの判定部の判定結果が、過負荷状態であった場合に、ブームの動作を停止する制御及び警報を発する制御の少なくとも一方の制御を含む過負荷防止制御を実施する制御部と、を備える。 One aspect of the overload prevention device according to the present invention is
An overload prevention device that has a boom and is built into a crane that transports suspended loads.
An acquisition unit that acquires a tipping moment that is a moment acting on the boom based on the load of the suspended load and includes a forward moment and a lateral moment as components.
Based on the forward moment, the first determination unit that determines whether the crane is in an overloaded state with respect to the front, and
The second judgment unit that determines whether the crane is overloaded with respect to the side, and
A third judgment unit that determines whether the crane is overloaded with respect to strength,
When the judgment result of at least one of the first judgment unit, the second judgment unit, and the third judgment unit is an overload state, the control for stopping the operation of the boom and the control for issuing an alarm are performed. A control unit that performs overload prevention control including at least one control is provided.
　本発明によれば、ブームに作用する転倒モーメントの前方転倒成分を基準として過負荷を判断するので、ブームを斜め前に向けたときの作業範囲を拡大できる。 According to the present invention, since the overload is determined based on the forward overturning component of the overturning moment acting on the boom, the working range when the boom is directed diagonally forward can be expanded.
図１は、積載形トラッククレーンの側面図である。FIG. 1 is a side view of a loaded truck crane. 図２は、積載形トラッククレーンの平面図である。FIG. 2 is a plan view of a loaded truck crane. 図３は、小型クレーンの油圧回路図である。FIG. 3 is a hydraulic circuit diagram of a small crane. 図４は、前方作業範囲の説明図である。FIG. 4 is an explanatory view of the forward working range. 図５は、第１実施形態に係る過負荷防止装置のブロック図である。FIG. 5 is a block diagram of the overload prevention device according to the first embodiment. 図６は、第１実施形態における前方安定監視部の制御のフローチャートである。FIG. 6 is a flowchart of control of the forward stability monitoring unit according to the first embodiment. 図７は、第２実施形態における前方安定監視部の制御のフローチャートである。FIG. 7 is a flowchart of control of the forward stability monitoring unit according to the second embodiment.
　つぎに、本発明の実施形態を図面に基づき説明する。〔第１実施形態〕
　本発明の第１実施形態に係る過負荷防止装置ＡＡは、移動式クレーンの過負荷による転倒を防止するのに用いられる。移動式クレーンとして、オールテレーンクレーン、ラフテレーンクレーン、トラッククレーン、積載形トラッククレーンなどが挙げられる。本実施形態の過負荷防止装置ＡＡは、これらのなかでも積載形トラッククレーンに好適に用いられる。 Next, an embodiment of the present invention will be described with reference to the drawings. [First Embodiment]
The overload prevention device AA according to the first embodiment of the present invention is used to prevent the mobile crane from tipping over due to overload. Examples of mobile cranes include all-terrain cranes, rough terrain cranes, truck cranes, and loaded truck cranes. Among these, the overload prevention device AA of the present embodiment is preferably used for a load-type truck crane.
（積載形トラッククレーン）
　まず、積載形トラッククレーンＣＲを説明する。図１に示すように、積載形トラッククレーンＣＲは汎用トラック１０を有する。汎用トラック１０の前方部分には運転室１１が設けられており、後方部分には荷台１２が設けられている。汎用トラック１０の車両フレーム１３のうち、運転室１１と荷台１２との間の部分には、小型クレーン２０が搭載されている。 (Load type truck crane)
First, the loading type truck crane CR will be described. As shown in FIG. 1, the load-type truck crane CR has a general-purpose truck 10. A driver's cab 11 is provided in the front portion of the general-purpose truck 10, and a loading platform 12 is provided in the rear portion. A small crane 20 is mounted in a portion of the vehicle frame 13 of the general-purpose truck 10 between the driver's cab 11 and the loading platform 12.
　小型クレーン２０は車両フレーム１３上に固定されたベース２１を有する。ベース２１にはポスト２２が旋回可能に設けられている。ポスト２２の上端部にはブーム２３が起伏可能に設けられている。ポスト２２にはウインチが内蔵されている。このウインチから延ばされたワイヤロープはブーム２３の先端部まで導かれている。ワイヤロープはブーム２３の先端部とフック２４とに設けられた滑車に掛け回されている。これにより、フック２４はブーム２３の先端部から吊り下げられている。フック２４には吊荷が吊り下げられる。 The small crane 20 has a base 21 fixed on the vehicle frame 13. A post 22 is provided on the base 21 so as to be rotatable. A boom 23 is provided on the upper end of the post 22 so as to be undulating. The post 22 has a built-in winch. The wire rope extended from this winch is guided to the tip of the boom 23. The wire rope is hung around a pulley provided at the tip of the boom 23 and the hook 24. As a result, the hook 24 is suspended from the tip of the boom 23. A suspended load is suspended from the hook 24.
　ポスト２２、ブーム２３、フック２４などから構成され、吊荷の搬送に用いられる装置を「クレーン装置」と称する。ブーム２３は伸縮、起伏可能であるとともに、旋回中心Ｏを中心として旋回可能である。本明細書では、ブーム２３の長さをＬと表記する。ブーム２３の起伏角（水平面に対する角度）をφと表記する。また、図２に示すように、ブーム２３の旋回角をθと表記する。旋回角θは積載形トラッククレーンＣＲの真正面を０°とする。 A device composed of a post 22, a boom 23, a hook 24, etc. and used for transporting a suspended load is referred to as a "crane device". The boom 23 can be expanded and contracted and undulated, and can be swiveled around the swivel center O. In this specification, the length of the boom 23 is referred to as L. The undulation angle (angle with respect to the horizontal plane) of the boom 23 is expressed as φ. Further, as shown in FIG. 2, the turning angle of the boom 23 is referred to as θ. The turning angle θ is 0 ° directly in front of the loaded truck crane CR.
　小型クレーン２０は、クレーン装置のほか、アウトリガジャッキ２５を有する。アウトリガジャッキ２５は小型クレーン２０の左右両側に配置されている。左右のアウトリガジャッキ２５とブーム２３の旋回中心Ｏとは車幅方向に並んで配置されている。すなわち、左右のアウトリガジャッキ２５とブーム２３の旋回中心Ｏとは、汎用トラック１０の前後方向に同位置に配置されているか、短い距離を隔てて配置されている。なお、荷台１２の後方左右に、アウトリガジャッキ２５とは別のアウトリガジャッキを設けてもよい。 The small crane 20 has an outrigger jack 25 in addition to the crane device. The outrigger jacks 25 are arranged on the left and right sides of the small crane 20. The left and right outrigger jacks 25 and the turning center O of the boom 23 are arranged side by side in the vehicle width direction. That is, the left and right outrigger jacks 25 and the turning center O of the boom 23 are arranged at the same position in the front-rear direction of the general-purpose truck 10 or are arranged at short distances. An outrigger jack different from the outrigger jack 25 may be provided on the left and right rear of the loading platform 12.
　小型クレーン２０は図３に示す油圧回路３０により油圧駆動される。油圧回路３０は油圧バルブユニット３１を有する。油圧バルブユニット３１の入口ポートは主油路３４を介してタンク３２に接続している。主油路３４には油圧ポンプ３３が設けられている。油圧ポンプ３３はＰＴＯ（パワーテイクオフ）装置を介して汎用トラック１０のエンジン１４に接続されており、エンジン１４により駆動される。油圧ポンプ３３によりタンク３２内の作動油が油圧バルブユニット３１に供給される。油圧バルブユニット３１の出口ポートは戻油路３５を介してタンク３２に接続している。 The small crane 20 is hydraulically driven by the hydraulic circuit 30 shown in FIG. The hydraulic circuit 30 has a hydraulic valve unit 31. The inlet port of the hydraulic valve unit 31 is connected to the tank 32 via the main oil passage 34. A hydraulic pump 33 is provided in the main oil passage 34. The hydraulic pump 33 is connected to the engine 14 of the general-purpose truck 10 via a PTO (power take-off) device, and is driven by the engine 14. The hydraulic oil in the tank 32 is supplied to the hydraulic valve unit 31 by the hydraulic pump 33. The outlet port of the hydraulic valve unit 31 is connected to the tank 32 via the return oil passage 35.
　油圧バルブユニット３１には複数の油圧アクチュエータ３６ａ～３６ｆが接続されている。油圧アクチュエータ３６ａ～３６ｆは、ブーム伸縮用油圧シリンダ３６ａ、ウインチ用油圧モータ３６ｂ、ブーム起伏用油圧シリンダ３６ｃ、旋回用油圧モータ３６ｄ、およびアウトリガ用油圧シリンダ３６ｅ、３６ｆである。ブーム伸縮用油圧シリンダ３６ａの動作によりブーム２３が伸縮する。ウインチ用油圧モータ３６ｂの動作によりフック２４が巻上巻下作動する。ブーム起伏用油圧シリンダ３６ｃの動作によりブーム２３が起伏する。旋回用油圧モータ３６ｄの動作によりポスト２２が旋回する。アウトリガ用油圧シリンダ３６ｅ、３６ｆの動作によりアウトリガジャッキ２５、２５が伸縮する。 A plurality of hydraulic actuators 36a to 36f are connected to the hydraulic valve unit 31. The hydraulic actuators 36a to 36f are a boom expansion / contraction hydraulic cylinder 36a, a winch hydraulic motor 36b, a boom undulating hydraulic cylinder 36c, a swivel hydraulic motor 36d, and an outrigger hydraulic cylinders 36e and 36f. The boom 23 expands and contracts due to the operation of the boom expansion and contraction hydraulic cylinder 36a. The hook 24 is wound up and down by the operation of the winch hydraulic motor 36b. The boom 23 undulates due to the operation of the boom undulating hydraulic cylinder 36c. The post 22 is swiveled by the operation of the swivel hydraulic motor 36d. The outrigger jacks 25 and 25 expand and contract by the operation of the outrigger hydraulic cylinders 36e and 36f.
　油圧バルブユニット３１には、伸縮用切換制御弁３７ａ、ウインチ用切換制御弁３７ｂ、起伏用切換制御弁３７ｃ、旋回用切換制御弁３７ｄ、およびアウトリガ用切換制御弁３７ｅ、３７ｆが設けられている。伸縮用切換制御弁３７ａにブーム伸縮用油圧シリンダ３６ａが接続している。ウインチ用切換制御弁３７ｂにウインチ用油圧モータ３６ｂが接続している。起伏用切換制御弁３７ｃにブーム起伏用油圧シリンダ３６ｃが接続している。旋回用切換制御弁３７ｄに旋回用油圧モータ３６ｄが接続している。アウトリガ用切換制御弁３７ｅ、３７ｆにアウトリガ用油圧シリンダ３６ｅ、３６ｆが、それぞれ接続している。各切換制御弁３７ａ～３７ｆは、油圧ポンプ３３から供給された作動油の方向および流量を制御して、油圧アクチュエータ３６ａ～３６ｆの動作を制御する。 The hydraulic valve unit 31 is provided with a telescopic switching control valve 37a, a winch switching control valve 37b, an undulating switching control valve 37c, a swivel switching control valve 37d, and outrigger switching control valves 37e and 37f. A boom expansion / contraction hydraulic cylinder 36a is connected to the expansion / contraction switching control valve 37a. A winch hydraulic motor 36b is connected to the winch switching control valve 37b. A boom undulating hydraulic cylinder 36c is connected to the undulating switching control valve 37c. A swivel hydraulic motor 36d is connected to the swivel switching control valve 37d. The outrigger hydraulic cylinders 36e and 36f are connected to the outrigger switching control valves 37e and 37f, respectively. The switching control valves 37a to 37f control the direction and flow rate of the hydraulic oil supplied from the hydraulic pump 33 to control the operation of the hydraulic actuators 36a to 36f.
　各切換制御弁３７ａ～３７ｆのスプールにはリンク機構などを介して操作レバーが連結されている。操作レバーを手動操作することにより、切換制御弁３７ａ～３７ｆのスプール位置を切り換えることができる。すなわち、操作レバーにより切換制御弁３７ａ～３７ｆを直接操作できる。 An operation lever is connected to the spools of the switching control valves 37a to 37f via a link mechanism or the like. By manually operating the operating lever, the spool positions of the switching control valves 37a to 37f can be switched. That is, the switching control valves 37a to 37f can be directly operated by the operating lever.
　図１に示すように、小型クレーン２０は操作レバー群２６を有する。操作レバー群２６を構成する操作レバーが切換制御弁３７ａ～３７ｆのいずれかに連結されている。操作者は操作レバー群２６を用いて小型クレーン２０を操作できる。 As shown in FIG. 1, the small crane 20 has an operating lever group 26. The operating levers constituting the operating lever group 26 are connected to any of the switching control valves 37a to 37f. The operator can operate the small crane 20 by using the operating lever group 26.
　図３に示すように、切換制御弁３７ａ～３７ｆのスプールには、それぞれパイロットシリンダ３８ａ～３８ｆが取り付けられている。パイロットシリンダ３８ａ～３８ｆの動作によっても、切換制御弁３７ａ～３７ｆのスプール位置を切り換えることができる。 As shown in FIG. 3, pilot cylinders 38a to 38f are attached to the spools of the switching control valves 37a to 37f, respectively. The spool positions of the switching control valves 37a to 37f can also be switched by the operation of the pilot cylinders 38a to 38f.
　各パイロットシリンダ３８ａ～３８ｆは、複動形シリンダであり、右側油室への作動油の給排を行なう電磁弁と、左側油室への作動油の給排を行なう電磁弁とが付設されている。これらの電磁弁は制御装置４０に接続されている。 Each of the pilot cylinders 38a to 38f is a double-acting cylinder, and is provided with a solenoid valve for supplying and discharging hydraulic oil to the right oil chamber and an electromagnetic valve for supplying and discharging hydraulic oil to the left oil chamber. There is. These solenoid valves are connected to the control device 40.
　制御装置４０はＣＰＵ、メモリなどで構成されたコンピュータである。制御装置４０からの制御信号に基づいて電磁弁が動作することで、パイロットシリンダ３８ａ～３８ｆが駆動し、切換制御弁３７ａ～３７ｆのスプール位置が切り換わる。このようにして、制御装置４０は小型クレーン２０の動作を制御する。 The control device 40 is a computer composed of a CPU, a memory, and the like. By operating the solenoid valve based on the control signal from the control device 40, the pilot cylinders 38a to 38f are driven, and the spool positions of the switching control valves 37a to 37f are switched. In this way, the control device 40 controls the operation of the small crane 20.
　制御装置４０は遠隔操作端末４１と双方向に無線通信または有線通信可能である。遠隔操作端末４１は、いわゆるラジコン送信機をはじめとする無線操作端末でもよいし、有線操作端末でもよい。遠隔操作端末４１は各種のスイッチ、アクセルトリガなどからなる入力部が搭載されている。 The control device 40 can perform bidirectional wireless communication or wired communication with the remote control terminal 41. The remote control terminal 41 may be a wireless control terminal such as a so-called radio control transmitter, or a wired control terminal. The remote control terminal 41 is equipped with an input unit including various switches and an accelerator trigger.
　操作者が遠隔操作端末４１の入力部を操作すると、遠隔操作端末４１は制御装置４０に操作信号を送信する。制御装置４０はその操作信号に基づいて油圧回路３０を制御して小型クレーン２０を動作させる。このようにして、操作者は遠隔操作端末４１を用いて小型クレーン２０を遠隔操作できる。 When the operator operates the input unit of the remote control terminal 41, the remote control terminal 41 transmits an operation signal to the control device 40. The control device 40 controls the hydraulic circuit 30 based on the operation signal to operate the small crane 20. In this way, the operator can remotely control the small crane 20 using the remote control terminal 41.
　小型クレーン２０はブーム２３の姿勢を測定する姿勢測定器を有する。本実施形態の場合、ブーム２３の姿勢はブーム２３の長さＬ、起伏角φおよび旋回角θによって表される。姿勢測定器はこれらの各パラメータＬ、φ、θを測定する複数の測定器からなる。すなわち、姿勢測定器は長さ測定器４２、起伏角測定器４３および旋回角測定器４４からなる。 The small crane 20 has an attitude measuring device that measures the attitude of the boom 23. In the case of the present embodiment, the posture of the boom 23 is represented by the length L of the boom 23, the undulation angle φ, and the turning angle θ. The posture measuring instrument consists of a plurality of measuring instruments that measure each of these parameters L, φ, and θ. That is, the posture measuring device includes a length measuring device 42, an undulation angle measuring device 43, and a turning angle measuring device 44.
　長さ測定器４２はブーム２３の長さＬを測定する。長さ測定器４２の構成は特に限定されないが、ブーム２３の先端部にコードの端部が固定されたコードリールの回転角をポテンショメータで読み取る構成が挙げられる。 The length measuring device 42 measures the length L of the boom 23. The configuration of the length measuring instrument 42 is not particularly limited, and examples thereof include a configuration in which the rotation angle of the cord reel in which the end of the cord is fixed to the tip of the boom 23 is read by a potentiometer.
　起伏角測定器４３はブーム２３の起伏角φを測定する。起伏角測定器４３の構成は特に限定されないが、ポテンショメータに振り子を取り付けた振子式の角度測定器をブーム２３に設ける構成が挙げられる。 The undulation angle measuring device 43 measures the undulation angle φ of the boom 23. The configuration of the undulation angle measuring device 43 is not particularly limited, and examples thereof include a configuration in which a pendulum type angle measuring device in which a pendulum is attached to a potentiometer is provided on the boom 23.
　旋回角測定器４４はブーム２３の旋回角θを測定する。旋回角測定器４４の構成は特に限定されないが、ベース２１またはポスト２２に設けた複数の近接スイッチによりブーム２３の旋回角θを離散的に検知する構成のほか、ポスト２２を旋回させる油圧モータの回転角をポテンショメータで読み取る構成が挙げられる。 The turning angle measuring device 44 measures the turning angle θ of the boom 23. The configuration of the swivel angle measuring device 44 is not particularly limited, but in addition to a configuration in which the swivel angle θ of the boom 23 is discretely detected by a plurality of proximity switches provided on the base 21 or the post 22, a hydraulic motor that swivels the post 22 An example is a configuration in which the rotation angle is read by a potentiometer.
　また、小型クレーン２０はブーム２３に作用する転倒モーメントＭを測定するモーメント測定器４５を有する。モーメント測定器４５は、取得部の一例に該当する。転倒モーメントＭは吊荷の荷重およびブーム２３の自重により生じる。モーメント測定器４５の構成は特に限定されないが、ブーム２３を起伏させるブーム起伏用油圧シリンダ３６ｃ内の油圧を圧力センサで測定する構成が挙げられる。 Further, the small crane 20 has a moment measuring device 45 for measuring the overturning moment M acting on the boom 23. The moment measuring device 45 corresponds to an example of the acquisition unit. The overturning moment M is generated by the load of the suspended load and the own weight of the boom 23. The configuration of the moment measuring device 45 is not particularly limited, and examples thereof include a configuration in which the oil pressure in the boom undulating hydraulic cylinder 36c that undulates the boom 23 is measured by a pressure sensor.
（過負荷防止装置）
　つぎに、本実施形態の過負荷防止装置ＡＡを説明する。制御装置４０は、小型クレーン２０の動作を制御する機能のほか、過負荷防止装置ＡＡとしての機能も有する。なお、過負荷防止装置ＡＡを制御装置４０とは別のコンピュータで構成してもよい。 (Overload prevention device)
Next, the overload prevention device AA of the present embodiment will be described. The control device 40 has a function as an overload prevention device AA in addition to a function of controlling the operation of the small crane 20. The overload prevention device AA may be configured by a computer different from the control device 40.
　図５に示すように、過負荷防止装置ＡＡには、姿勢測定器（長さ測定器４２、起伏角測定器４３、旋回角測定器４４）およびモーメント測定器４５の測定値が入力されている。すなわち、過負荷防止装置ＡＡには、ブーム２３の長さＬd、起伏角φdおよび旋回角θdの各測定値と、転倒モーメントＭdの測定値とが入力されている。 As shown in FIG. 5, the measurement values of the posture measuring device (length measuring device 42, undulation angle measuring device 43, turning angle measuring device 44) and the moment measuring device 45 are input to the overload prevention device AA. .. That is, the overload prevention device AA is input with the measured values of the boom 23 length L d , the undulation angle φ d, and the turning angle θ d , and the measured values of the overturning moment M d.
　過負荷防止装置ＡＡは、これらの測定値Ｌd、φd、θd、Ｍdに基づき、小型クレーン２０の過負荷状態を検知する。ここで、「過負荷状態」とは、転倒モーメントが安定モーメントを超えて積載形トラッククレーンＣＲが転倒する状態、および吊荷の荷重による負荷が小型クレーン２０の構成部材の耐荷重を超えた状態、あるいはそれらの状態に近づいた状態を意味する。 The overload prevention device AA detects the overload state of the small crane 20 based on these measured values L d , φ d , θ d , and M d. Here, the "overload state" is a state in which the overload moment exceeds the stable moment and the load-type truck crane CR overturns, and a state in which the load due to the load of the suspended load exceeds the load capacity of the constituent members of the small crane 20. , Or a state approaching those states.
　過負荷防止装置ＡＡは、前方安定監視部５１、側方安定監視部５２および強度限界監視部５３を有する。前方安定監視部５１は、制御部及び第一判定部の一例に該当し、積載形トラッククレーンＣＲが前方へ転倒するか否か、すなわち前方への安定を監視する。側方安定監視部５２は、第二判定部の一例に該当し積載形トラッククレーンＣＲが側方へ転倒するか否か、すなわち側方への安定を監視する。強度限界監視部５３は、第三判定部の一例に該当し、吊荷の荷重による負荷が構成部材の耐荷重を超えるか否かを監視する。以下、それぞれの制御を順に説明する。 The overload prevention device AA has a front stability monitoring unit 51, a side stability monitoring unit 52, and a strength limit monitoring unit 53. The forward stability monitoring unit 51 corresponds to an example of the control unit and the first determination unit, and monitors whether or not the loaded truck crane CR falls forward, that is, the stability in the forward direction. The lateral stability monitoring unit 52 corresponds to an example of the second determination unit and monitors whether or not the loaded truck crane CR falls sideways, that is, lateral stability. The strength limit monitoring unit 53 corresponds to an example of the third determination unit, and monitors whether or not the load due to the load of the suspended load exceeds the withstand load of the constituent members. Hereinafter, each control will be described in order.
　（前方安定監視）
　まず、前方安定監視の原理を説明する。図２に示すように、ブーム２３が斜め前に旋回しているとする。この場合、ブーム２３に作用する転倒モーメントＭのうち、前方転倒成分の大きさＭfは式（１）で求められる。以下、Ｍfを「前方モーメント」と称する。
Figure JPOXMLDOC01-appb-M000001
   (Forward stability monitoring)
First, the principle of forward stability monitoring will be described. As shown in FIG. 2, it is assumed that the boom 23 is turning diagonally forward. In this case, of the overturning moment M acting on the boom 23, the magnitude M f of the forward overturning component is obtained by the equation (1). Hereinafter, M f is referred to as "forward moment".
Figure JPOXMLDOC01-appb-M000001
　積載形トラッククレーンＣＲの前方への安定が確保される前方モーメントＭfの最大値を前方定格モーメントＭf-limとする。前方定格モーメントＭf-limは、第一閾値の一例に該当し、予め定められた値である。前方定格モーメントＭf-limは、例えば、荷台１２に荷物を積載しない空荷状態でブーム２３が汎用トラック１０の真正面を向いた、最も前方転倒しやすい状態において、汎用トラック１０の後輪が浮き上がる限界の転倒モーメントの大きさに設定される。上記限界転倒モーメントの大きさに安全率（１未満の値）をかけた値を前方定格モーメントＭf-limとしてもよい。また、積載形トラッククレーンＣＲの側方への安定モーメントを基準として、側方安定モーメントの大きさの所定割合（例えば２５％）を前方定格モーメントＭf-limとして設定してもよい。前方定格モーメントＭf-limは、積載形クレーンが前方に転倒しない前方モーメントの上限として設定される。第一閾値は、クレーンが前方に転倒しない荷重の上限として予め設定される。第一閾値は、ブーム２３が取り得る旋回角と対応付けて記憶部６０に記憶されている。 The maximum value of the forward moment M f that ensures the forward stability of the loaded truck crane CR is defined as the forward rated moment M f-lim . The forward rated moment M f-lim corresponds to an example of the first threshold value and is a predetermined value. The front rated moment M f-lim means that, for example, the rear wheel of the general-purpose truck 10 is lifted when the boom 23 faces directly in front of the general-purpose truck 10 in an empty state where no load is loaded on the loading platform 12 and the general-purpose truck 10 is most likely to fall forward. It is set to the magnitude of the limit overturning moment. The value obtained by multiplying the magnitude of the critical overturning moment by the safety factor (value less than 1) may be the forward rated moment M f-lim. Further, a predetermined ratio (for example, 25%) of the magnitude of the lateral stabilizing moment may be set as the forward rated moment M f-lim with reference to the lateral stabilizing moment of the loaded truck crane CR. The forward rated moment M f-lim is set as the upper limit of the forward moment at which the loaded crane does not tip over forward. The first threshold is preset as an upper limit of the load that prevents the crane from tipping forward. The first threshold value is stored in the storage unit 60 in association with the turning angle that the boom 23 can take.
　前方モーメントＭfと前方定格モーメントＭf-limとを比較すれば、積載形トラッククレーンＣＲが前方へ転倒するか否かを判断できる。具体的には、前方モーメントＭfが前方定格モーメントＭf-lim以下の場合は、前方転倒しないと判断する。また、前方モーメントＭfが前方定格モーメントＭf-limを超える場合は、前方転倒する（過負荷）と判断する。 By comparing the forward moment M f and the forward rated moment M f-lim , it can be determined whether or not the loaded truck crane CR falls forward. Specifically, when the forward moment M f is equal to or less than the forward rated moment M f-lim , it is determined that the vehicle does not tip forward. If the forward moment M f exceeds the forward rated moment M f-lim , it is determined that the vehicle falls forward (overload).
　図４に示すように、吊荷の荷重が閾値に達したことに基づいて一律に過負荷と判断する場合、前方の作業範囲Ｒ１は半円形の領域となる。これに対して、上記のように、ブーム２３に作用する転倒モーメントの前方転倒成分Ｍfを基準として過負荷を判断する場合、前方の作業範囲Ｒ２は作業範囲Ｒ１を含んだ横長の領域となる。このように、上記の方法によれば、ブーム２３を斜め前に向けたときの作業範囲を拡大できる。 As shown in FIG. 4, when it is uniformly determined that the overload is overloaded based on the fact that the load of the suspended load reaches the threshold value, the work range R1 in front becomes a semi-circular region. On the other hand, as described above, when the overload is determined based on the forward overturning component M f of the overturning moment acting on the boom 23, the front working range R2 is a horizontally long region including the working range R1. .. As described above, according to the above method, the working range when the boom 23 is directed diagonally forward can be expanded.
　以上の原理を踏まえ、本実施形態の前方安定監視部５１はつぎの制御を行なう。前方安定監視部５１には、予め、前方定格モーメントＭf-limが記憶されている。よって、前方安定監視部５１は、記憶部としての機能も有する。図６に示すように、まず、前方安定監視部５１は旋回角測定器４４およびモーメント測定器４５から測定値θd、Ｍdを取得する（ステップＳ１１）。 Based on the above principle, the forward stability monitoring unit 51 of the present embodiment performs the following control. The front stability monitoring unit 51 stores the front rated moment M f-lim in advance. Therefore, the forward stability monitoring unit 51 also has a function as a storage unit. As shown in FIG. 6, first, the forward stability monitoring unit 51 acquires the measured values θ d and M d from the turning angle measuring device 44 and the moment measuring device 45 (step S11).
　つぎに、前方安定監視部５１は、ブーム２３が積載形トラッククレーンＣＲの前方領域に配置されていることを確認する（ステップＳ１２）。ブーム２３が前方領域に配置されているとは、ブーム２３の先端部（フック２４）が前方への転倒基線よりも前方に配置されていることを意味する。前方への転倒基線は、例えば、左右のアウトリガジャッキ２５の接地位置を結ぶ線である。左右のアウトリガジャッキ２５が旋回中心Ｏの真横に配置されている場合には、ブーム２３の旋回角θdが－９０°～＋９０°の範囲内のときに、ブーム２３が前方領域に配置されていると判断すればよい。換言すれば、ブーム２３が前方領域に配置されている状態は、吊荷の荷重Ｗに基づいて、ブーム２３に作用する前方モーメントの大きさが０より大きい状態を意味する。 Next, the forward stability monitoring unit 51 confirms that the boom 23 is arranged in the front region of the loaded truck crane CR (step S12). The fact that the boom 23 is arranged in the front region means that the tip end portion (hook 24) of the boom 23 is arranged in front of the forward tipping baseline. The forward overturning baseline is, for example, a line connecting the grounding positions of the left and right outrigger jacks 25. When the left and right outrigger jacks 25 are arranged right next to the turning center O , the boom 23 is arranged in the front region when the turning angle θ d of the boom 23 is within the range of −90 ° to + 90 °. You can judge that there is. In other words, the state in which the boom 23 is arranged in the front region means a state in which the magnitude of the forward moment acting on the boom 23 is greater than 0 based on the load W of the suspended load.
　ブーム２３が前方領域に配置されていない場合は処理を終了する。一方、ブーム２３が前方領域に配置されている場合は、処理を継続する。 If the boom 23 is not located in the front area, the process ends. On the other hand, when the boom 23 is arranged in the front region, the process is continued.
　つぎに、前方安定監視部５１は、式（２）に従い、旋回角および転倒モーメントの測定値θd、Ｍdから、転倒モーメントＭの前方転倒成分、すなわち前方モーメントＭfを求める（ステップＳ１３）。 Next, the forward stability monitoring unit 51 obtains the forward overturning component of the overturning moment M, that is, the forward moment M f from the measured values θ d and M d of the turning angle and the overturning moment according to the equation (2) (step S13). ..
Figure JPOXMLDOC01-appb-M000002
  
Figure JPOXMLDOC01-appb-M000002
  
　転倒モーメントは、成分として、前方モーメントＭｆと側方モーメントとを有する。ブーム２３の長さ及び起伏角を固定した場合、ブーム２３の旋回角が0°の場合に、転倒モーメントのうちの前方モーメントＭｆが最大となり、ブーム２３の旋回角が９０°又は－９０°の場合に、転倒モーメントのうちの前方モーメントＭｆが最小となる。前方モーメントとは、ブーム２３に作用するモーメントであって、積載形トラッククレーンＣＲの左右方向に平行な軸周りのモーメントを意味する。又、側方モーメントとは、ブーム２３に作用するモーメントであって、積載形トラッククレーンＣＲの前後方向に平行な軸周りのモーメントを意味する。 The overturning moment has a forward moment M f and a lateral moment as components. When the length and undulation angle of the boom 23 are fixed, when the turning angle of the boom 23 is 0 °, the forward moment M f of the overturning moment becomes the maximum, and the turning angle of the boom 23 is 90 ° or −90 °. In the case of, the forward moment M f of the overturning moment becomes the minimum. The forward moment is a moment acting on the boom 23, and means a moment around an axis parallel to the left-right direction of the loaded truck crane CR. Further, the lateral moment is a moment acting on the boom 23, and means a moment around an axis parallel to the front-rear direction of the loaded truck crane CR.
　つぎに、前方安定監視部５１は、前方モーメントＭfと前方定格モーメントＭf-limとを比較する（ステップＳ１４）。そして、前方モーメントＭfが前方定格モーメントＭf-limを超えたときに、過負荷と判断する（ステップＳ１５）。又、前方安定監視部５１は、過負荷と判断した場合、ブーム２３の動作を停止する制御及び警報を発する制御の少なくとも一方の制御を含む過負荷防止制御を実施する。尚、過負荷防止制御は、ブーム２３の動作を停止する制御及び警報を発する制御以外の制御を含んでもよい。 Next, the forward stability monitoring unit 51 compares the forward moment M f with the forward rated moment M f-lim (step S14). Then, when the forward moment M f exceeds the forward rated moment M f-lim , it is determined that the load is overloaded (step S15). Further, the forward stability monitoring unit 51 implements overload prevention control including at least one of control of stopping the operation of the boom 23 and control of issuing an alarm when it is determined that the load is overloaded. The overload prevention control may include a control other than a control for stopping the operation of the boom 23 and a control for issuing an alarm.
　（側方安定監視）
　つぎに、側方安定監視を説明する。
　側方安定監視部５２は積載形トラッククレーンＣＲが側方へ転倒する条件となったとき、あるいはそのような条件に近づいたときに過負荷と判断する。側方安定監視部５２の具体的な制御は特に限定されないが、例えば、以下の制御を行なう。 (Side stability monitoring)
Next, lateral stability monitoring will be described.
The lateral stability monitoring unit 52 determines that the load is overloaded when the load-type truck crane CR falls under the condition of falling sideways, or when such a condition is approached. The specific control of the lateral stability monitoring unit 52 is not particularly limited, but for example, the following control is performed.
　積載形トラッククレーンＣＲの側方への転倒モーメント（つまり、ブーム２３に作用する転倒モーメントのうちの側方モーメント）が大きくなると、それに従い反転倒側に設けられたアウトリガジャッキ２５の接地反力Ｆが小さくなる。これを利用して側方への安定を監視する。 When the lateral overturning moment of the loaded truck crane CR (that is, the lateral moment of the overturning moment acting on the boom 23) increases, the ground reaction force F of the outrigger jack 25 provided on the inverted overturning side accordingly. Becomes smaller. This is used to monitor lateral stability.
　積載形トラッククレーンＣＲは左右のアウトリガジャッキ２５の接地反力Ｆを測定する接地反力測定器４６を有する。接地反力測定器４６の構成は特に限定されないが、アウトリガジャッキ２５の油室内の油圧を測定する油圧センサを用いる構成が挙げられる。アウトリガジャッキ２５の保持側油室と反保持側油室の差圧と、ジャッキシリンダの受圧面積とから接地反力Ｆを算出できる。 The load-type truck crane CR has a ground reaction force measuring device 46 that measures the ground reaction force F of the left and right outrigger jacks 25. The configuration of the ground reaction force measuring device 46 is not particularly limited, and examples thereof include a configuration using a hydraulic sensor that measures the oil pressure in the oil chamber of the outrigger jack 25. The ground contact reaction force F can be calculated from the differential pressure between the holding side oil chamber and the non-holding side oil chamber of the outrigger jack 25 and the pressure receiving area of the jack cylinder.
　図５に示すように、接地反力測定器４６の測定値、すなわち、アウトリガジャッキ２５の接地反力Ｆdは過負荷防止装置ＡＡに入力されている。側方安定監視部５２は、左右のアウトリガジャッキ２５のいずれかの接地反力Ｆdが反力閾値Ｆlimを下回ったときに、過負荷と判断する。反力閾値Ｆlimは側方安定監視部５２に予め設定された値である。反力閾値Ｆlimは一の固定値でもよいし、ブーム２３の姿勢Ｌ、φ、θ、吊荷の荷重、アウトリガジャッキ２５の張出幅などに基づいて可変としてもよい。 As shown in FIG. 5, the measurement values of the ground reaction force measuring device 46, i.e., the ground reaction force F d outrigger jacks 25 are input to the overload prevention device AA. The lateral stability monitoring unit 52 determines that the load is overloaded when the ground contact reaction force F d of any of the left and right outrigger jacks 25 falls below the reaction force threshold value F lim. The reaction force threshold value F lim is a value preset in the lateral stability monitoring unit 52. The reaction force threshold value F lim may be a fixed value of 1, or may be variable based on the postures L, φ, θ of the boom 23, the load of the suspended load, the overhang width of the outrigger jack 25, and the like.
　側方安定監視部５２は、少なくともブーム２３が側方領域に配置されている場合に、側方安定監視を行なう。ブーム２３が側方領域に配置されているとは、ブーム２３の先端部（フック２４）が側方への転倒基線よりも側方に配置されていることを意味する。ブーム２３の前方領域と側方領域とは、積載形トラッククレーンＣＲの斜め前方において、一部重なる。また、アウトリガジャッキ２５の接地反力Ｆに基づいて側方安定監視を行なう場合、側方安定監視部５２はブーム２３の旋回角θによらず、常に側方安定監視を行なえばよい。したがって、ブーム２３が前方領域に配置されている場合は、前方安定監視とともに側方安定監視も行なわれる。前方安定監視部５１が過負荷と判断していない場合でも、側方安定監視部５２が過負荷と判断する場合がある。 The lateral stability monitoring unit 52 performs lateral stability monitoring at least when the boom 23 is arranged in the lateral region. The fact that the boom 23 is arranged in the lateral region means that the tip end portion (hook 24) of the boom 23 is arranged laterally from the lateral tipping baseline. The front area and the side area of the boom 23 partially overlap each other diagonally in front of the loaded truck crane CR. Further, when performing lateral stability monitoring based on the ground contact reaction force F of the outrigger jack 25, the side stability monitoring unit 52 may always perform lateral stability monitoring regardless of the turning angle θ of the boom 23. Therefore, when the boom 23 is arranged in the front region, lateral stability monitoring is performed as well as forward stability monitoring. Even if the front stability monitoring unit 51 does not determine that it is overloaded, the side stability monitoring unit 52 may determine that it is overloaded.
　（強度限界監視）
　つぎに、強度限界監視を説明する。強度限界監視部５３は吊荷の荷重による負荷が構成部材の耐荷重を超える条件となったときに過負荷と判断する。強度限界監視部５３の具体的な制御は特に限定されないが、例えば、以下の制御を行なう。 (Strength limit monitoring)
Next, the strength limit monitoring will be described. The strength limit monitoring unit 53 determines that the load is overloaded when the load due to the load of the suspended load exceeds the withstand load of the constituent members. The specific control of the strength limit monitoring unit 53 is not particularly limited, but for example, the following control is performed.
　強度限界監視部５３には、予め、強度定格モーメントＭs-lim（Ｌ、φ）が記憶されている。強度定格モーメントＭs-limは、ブーム２３などの構成部材が耐えうるモーメントとして、ブーム２３の長さＬおよび起伏角φごとに定められた値である。ブーム２３の長さＬおよび起伏角φは、ブーム２３の姿勢条件の一例に該当する。強度定格モーメントＭs-limは表形式で記憶してもよいし、ブーム２３の長さＬおよび起伏角φを変数とした関数として記憶してもよい。なお、強度定格モーメントＭs-limをブーム２３の長さＬ、起伏角φおよび旋回角θごとに定められた値としてもよい。また、強度定格モーメントＭs-limをブーム２３の長さＬなどに依存しない固定値としてもよい。 The strength rated moment M s-lim (L, φ) is stored in advance in the strength limit monitoring unit 53. The strength rated moment M s-lim is a value determined for each length L of the boom 23 and an undulation angle φ as a moment that a component member such as the boom 23 can withstand. The length L and the undulation angle φ of the boom 23 correspond to an example of the posture condition of the boom 23. The strength rated moment M s-lim may be stored in a table format, or may be stored as a function with the length L of the boom 23 and the undulation angle φ as variables. The strength rated moment M s-lim may be a value determined for each of the length L of the boom 23, the undulation angle φ, and the turning angle θ. Further, the strength rated moment M s-lim may be a fixed value that does not depend on the length L of the boom 23 or the like.
　まず、強度限界監視部５３は、長さ測定器４２、起伏角測定器４３およびモーメント測定器４５から測定値Ｌd、φd、Ｍdを取得する。つぎに、強度限界監視部５３は、ブーム２３の長さおよび起伏角の測定値Ｌd、φdに対応する強度定格モーメントＭs-lim（Ｌd、φd）を取得する。そして、強度限界監視部５３は、転倒モーメントＭdと強度定格モーメントＭs-lim（Ｌd、φd）とを比較する。そして、転倒モーメントＭdが強度定格モーメントＭs-lim（Ｌd、φd）を超えたときに、過負荷と判断する。 First, the strength limit monitoring unit 53 acquires the measured values L d , φ d , and M d from the length measuring device 42, the undulation angle measuring device 43, and the moment measuring device 45. Next, the strength limit monitoring unit 53 acquires the strength rated moment M s-lim (L d , φ d ) corresponding to the measured values L d and φ d of the length and undulation angle of the boom 23. Then, the strength limit monitoring unit 53 compares the overturning moment M d with the strength rated moment M s-lim (L d , φ d). Then, when the overturning moment M d exceeds the strength rated moment M s-lim (L d , φ d ), it is determined that the load is overloaded.
　なお、強度限界監視部５３はブーム２３の旋回角θによらず、常に強度限界監視を行なう。 The strength limit monitoring unit 53 constantly monitors the strength limit regardless of the turning angle θ of the boom 23.
　（最終判定）
　図５に示すように、過負荷防止装置ＡＡは最終判定部５４を有する。前方安定監視部５１、側方安定監視部５２および強度限界監視部５３の判断結果は、最終判定部５４に入力されている。最終判定部５４は、前方安定監視部５１、側方安定監視部５２および強度限界監視部５３の判断結果の論理和を求めて、最終的に過負荷の判定を行なう。すなわち、最終判定部５４は、前方安定監視部５１、側方安定監視部５２および強度限界監視部５３のいずれか一または複数が過負荷と判断している場合、過負荷と判定する。逆に、最終判定部５４は、前方安定監視部５１、側方安定監視部５２および強度限界監視部５３のいずれもが過負荷と判断していない場合、過負荷でないと判定する。 (Final judgment)
As shown in FIG. 5, the overload prevention device AA has a final determination unit 54. The determination results of the front stability monitoring unit 51, the side stability monitoring unit 52, and the strength limit monitoring unit 53 are input to the final determination unit 54. The final determination unit 54 obtains the logical sum of the determination results of the front stability monitoring unit 51, the side stability monitoring unit 52, and the strength limit monitoring unit 53, and finally determines the overload. That is, when any one or more of the front stability monitoring unit 51, the side stability monitoring unit 52, and the strength limit monitoring unit 53 determines that the load is overloaded, the final determination unit 54 determines that the load is overloaded. On the contrary, when none of the front stability monitoring unit 51, the side stability monitoring unit 52, and the strength limit monitoring unit 53 determines that the load is overloaded, the final determination unit 54 determines that the load is not overloaded.
　最終判定部５４の判定結果は制御装置４０に出力される。判定結果が過負荷の場合、制御装置４０はブーム２３の動作を自動的に停止してもよいし、警報を発してもよい。自動停止は転倒モーメントが増加する方向のブーム２３の動作を停止することにより行なわれる。すなわち、ブーム２３の伸長および倒伏を停止し、ブーム２３の収縮および起立を許容する。また、フック２４の巻き上げを停止し、フック２４の巻き下げを許容してもよい。なお、自動停止と警報のいずれか一方を行なってもよいし、両方を行なってもよい。 The determination result of the final determination unit 54 is output to the control device 40. When the determination result is an overload, the control device 40 may automatically stop the operation of the boom 23 or issue an alarm. The automatic stop is performed by stopping the operation of the boom 23 in the direction in which the overturning moment increases. That is, it stops the extension and lodging of the boom 23 and allows the boom 23 to contract and stand. Further, the winding of the hook 24 may be stopped and the winding of the hook 24 may be allowed. Either one of the automatic stop and the alarm may be performed, or both may be performed.
〔第２実施形態〕
　つぎに、本発明の第２実施形態に係る過負荷防止装置ＡＡを説明する。本実施形態の過負荷防止装置ＡＡの構成は、図５に示す構成と同様である。また、側方安定監視部５２、強度限界監視部５３および最終判定部５４の制御は第１実施形態と同様である。したがって、前方安定監視部５１の制御についてのみ説明する。 [Second Embodiment]
Next, the overload prevention device AA according to the second embodiment of the present invention will be described. The configuration of the overload prevention device AA of the present embodiment is the same as the configuration shown in FIG. Further, the control of the lateral stability monitoring unit 52, the strength limit monitoring unit 53, and the final determination unit 54 is the same as in the first embodiment. Therefore, only the control of the forward stability monitoring unit 51 will be described.
　前方安定監視部５１には、予め、転倒定格モーメントＭlim（θ）が記憶されている。転倒定格モーメントＭlimは、第二閾値の一例に該当し、ブーム２３に作用する転倒モーメントＭの前方転倒成分（前方モーメントＭf）が前方定格モーメントＭf-limとなるときの転倒モーメントＭとなるよう、ブーム２３の旋回角θごとに定められた値である。つまり、第二閾値は、第一閾値である前方定格モーメントと対応付けて設定される。前方安定監視部５１は、転倒定格モーメントＭlimを表形式で記憶してもよいし、ブーム２３の旋回角θを変数とした関数として記憶してもよい。よって、前方安定監視部５１は、第二閾値を記憶する記憶部としての機能も有する。 The forward stability monitoring unit 51 stores the overturning rated moment M lim (θ) in advance. The overturning rated moment M lim corresponds to an example of the second threshold value, and is the overturning moment M when the forward overturning component (forward moment M f ) of the overturning moment M acting on the boom 23 becomes the forward rated moment M f-lim. It is a value determined for each turning angle θ of the boom 23 so as to be. That is, the second threshold value is set in association with the forward rated moment, which is the first threshold value. The forward stability monitoring unit 51 may store the overturning rated moment M lim in a table format, or may store it as a function with the turning angle θ of the boom 23 as a variable. Therefore, the forward stability monitoring unit 51 also has a function as a storage unit for storing the second threshold value.
　図７に示すように、まず、前方安定監視部５１は旋回角測定器４４およびモーメント測定器４５から測定値θd、Ｍdを取得する（ステップＳ２１）。 As shown in FIG. 7, first, the forward stability monitoring unit 51 acquires the measured values θ d and M d from the turning angle measuring device 44 and the moment measuring device 45 (step S21).
　つぎに、前方安定監視部５１は、ブーム２３が積載形トラッククレーンＣＲの前方領域に配置されていることを確認する（ステップＳ２２）。ブーム２３が前方領域に配置されていない場合は処理を終了する。一方、ブーム２３が前方領域に配置されている場合は、処理を継続する。 Next, the forward stability monitoring unit 51 confirms that the boom 23 is arranged in the front region of the loaded truck crane CR (step S22). If the boom 23 is not located in the front region, the process ends. On the other hand, when the boom 23 is arranged in the front region, the process is continued.
　つぎに、前方安定監視部５１は、ブーム２３の旋回角の測定値θdに対応する転倒定格モーメントＭlim（θd）を取得する（ステップＳ２３）。そして、前方安定監視部５１は、転倒モーメントの測定値Ｍdと転倒定格モーメントＭlim（θd）とを比較する（ステップＳ２４）。そして、転倒モーメントＭdが転倒定格モーメントＭlim（θd）を超えたときに、過負荷と判断する（ステップＳ２５）。 Next, the forward stability monitoring unit 51 acquires the overturning rated moment M lim (θ d ) corresponding to the measured value θ d of the turning angle of the boom 23 (step S23). Then, the forward stability monitoring unit 51 compares the measured value M d of the overturning moment with the overturning rated moment M lim (θ d ) (step S24). Then, when the overturning moment M d exceeds the overturning rated moment M lim (θ d ), it is determined that the load is overloaded (step S25).
　このような処理により前方安定監視を行なったとしても、ブーム２３を斜め前に向けたときの作業範囲を拡大できる。 Even if forward stability monitoring is performed by such processing, the work range when the boom 23 is directed diagonally forward can be expanded.
　２０１９年１０月２９日出願の特願２０１９－１９６６３２の日本出願に含まれる明細書、図面、および要約書の開示内容は、すべて本願に援用される。 The disclosures of the specifications, drawings, and abstracts contained in the Japanese application of Japanese Patent Application No. 2019-196632 filed on October 29, 2019 are all incorporated herein by reference.
　（付記）
　本発明の参考例として以下の過負荷防止装置を実施することもできる。 (Additional note)
The following overload prevention device can also be implemented as a reference example of the present invention.
　（参考例１）
　参考例１に係る過負荷防止装置は、
　ブームを有する移動式クレーンの過負荷防止装置であって、
　前記ブームに作用する転倒モーメントの前方転倒成分が、予め定められた前方定格モーメントを超えたときに、過負荷と判断する。 (Reference example 1)
The overload prevention device according to Reference Example 1 is
An overload prevention device for mobile cranes with a boom.
When the forward overturning component of the overturning moment acting on the boom exceeds a predetermined forward rated moment, it is determined to be an overload.
　（参考例２）
　又、参考例１に係る過負荷防止装置を実施する場合に、参考例２に係る過負荷防止装置は、ブームに作用する転倒モーメントの測定値と、ブームの旋回角の測定値とを入力されてよい。
　この場合に、過負荷防止装置は、転倒モーメントおよび旋回角の測定値に基づいて、転倒モーメントの前方転倒成分を求める。そして、過負荷防止装置は、転倒モーメントの前方転倒成分が、前方定格モーメントを超えたときに、過負荷と判断してよい。 (Reference example 2)
Further, when the overload prevention device according to Reference Example 1 is implemented, the overload prevention device according to Reference Example 2 is input with the measured value of the overturning moment acting on the boom and the measured value of the turning angle of the boom. You can.
In this case, the overload prevention device obtains the forward overturning component of the overturning moment based on the measured values of the overturning moment and the turning angle. Then, the overload prevention device may determine that the overload is overloaded when the forward overturning component of the overturning moment exceeds the forward rated moment.
　（参考例３）
　又、参考例１に係る過負荷防止装置を実施する場合に、参考例３に係る過負荷防止装置は、ブームに作用する転倒モーメントの測定値と、ブームの旋回角の測定値とを入力されてよい。
　この場合に、過負荷防止装置は、ブームに作用する転倒モーメントの前方転倒成分が前方定格モーメントとなるときの転倒モーメントとなるよう、ブームの旋回角ごとに定められた転倒定格モーメントを記憶してもよい。そして、過負荷防止装置は、転倒モーメントの測定値が、ブームの旋回角の測定値に対応する転倒定格モーメントを超えたときに、過負荷と判断してよい。 (Reference example 3)
Further, when the overload prevention device according to Reference Example 1 is implemented, the overload prevention device according to Reference Example 3 is input with the measured value of the overturning moment acting on the boom and the measured value of the turning angle of the boom. You can.
In this case, the overload prevention device stores the overturning rated moment determined for each turning angle of the boom so that it becomes the overturning moment when the forward overturning component of the overturning moment acting on the boom becomes the forward rated moment. May be good. Then, the overload prevention device may determine that the overload is overloaded when the measured value of the overload moment exceeds the overturn rated moment corresponding to the measured value of the turning angle of the boom.
　本発明は、積載形トラッククレーンに限らず、種々の移動式クレーンに適用できる。 The present invention is applicable not only to loaded truck cranes but also to various mobile cranes.
　ＣＲ　積載形トラッククレーン
　１０　汎用トラック
　１１　運転室
　１２　荷台
　１３　車両フレーム
　１４　エンジン
　２０　小型クレーン
　２１　ベース
　２２　ポスト
　２３　ブーム
　２４　フック
　２５　アウトリガジャッキ
　２６　操作レバー群
　３０　油圧回路
　３０　油圧回路
　３１　油圧バルブユニット
　３２　タンク
　３３　油圧ポンプ
　３４　主油路
　３５　戻油路
　３６ａ　ブーム伸縮用油圧シリンダ（油圧アクチュエータ）
　３６ｂ　ウインチ用油圧モータ（油圧アクチュエータ）
　３６ｃ　ブーム起伏用油圧シリンダ（油圧アクチュエータ）
　３６ｄ　旋回用油圧モータ（油圧アクチュエータ）
　３６ｅ、３６ｆ　アウトリガ用油圧シリンダ（油圧アクチュエータ）
　３７ａ　伸縮用切換制御弁
　３７ｂ　ウインチ用切換制御弁
　３７ｃ　起伏用切換制御弁
　３７ｄ　旋回用切換制御弁
　３７ｅ、３７ｆ　アウトリガ用切換制御弁
　３８ａ、３８ｂ、３８ｃ、３８ｄ、３８ｅ、３８ｆ　パイロットシリンダ
　４０　制御装置
　４１　遠隔操作端末
　４２　長さ測定器
　４３　起伏角測定器
　４４　旋回角測定器
　４５　モーメント測定器
　４６　接地反力測定器
　ＡＡ　過負荷防止装置
　５１　前方安定監視部
　５２　側方安定監視部
　５３　強度限界監視部
　５４　最終判定部 CR Loading type truck crane 10 General-purpose truck 11 Driver's cab 12 Loading platform 13 Vehicle frame 14 Engine 20 Small crane 21 Base 22 Post 23 Boom 24 Hook 25 Out trigger jack 26 Operating lever group 30 Hydraulic circuit 30 Hydraulic circuit 31 Hydraulic valve unit 32 Tank 33 Pump 34 Main oil passage 35 Return oil passage 36a Boom expansion and contraction hydraulic cylinder (flood actuator)
36b winch hydraulic motor (hydraulic actuator)
36c Boom undulating hydraulic cylinder (hydraulic actuator)
36d Hydraulic motor for turning (hydraulic actuator)
36e, 36f Hydraulic cylinder for outriggers (hydraulic actuator)
37a Expansion / contraction switching control valve 37b Winch switching control valve 37c Undulation switching control valve 37d Swing switching control valve 37e, 37f Outrigger switching control valve 38a, 38b, 38c, 38d, 38e, 38f Pilot cylinder 40 Control device 41 Remote Operation terminal 42 Length measuring device 43 Undulating angle measuring device 44 Turning angle measuring device 45 Moment measuring device 46 Ground reaction force measuring device AA Overload prevention device 51 Front stability monitoring unit 52 Side stability monitoring unit 53 Strength limit monitoring unit 54 Final Judgment unit

Claims (7)

  1. 　ブームを有し、吊荷を搬送するクレーンに組み込まれる過負荷防止装置であって、
    　前記吊荷の荷重に基づいて前記ブームに作用するモーメントであって、前方モーメント及び側方モーメントを成分として含む転倒モーメントを取得する取得部と、
    　前記転倒モーメントに含まれる前記前方モーメントが、第一閾値よりも大きい場合に、前記ブームの動作を停止する制御及び警報を発する制御の何れか一方の制御を含む過負荷防止制御を実施する制御部と、を備える
    　過負荷防止装置。     An overload prevention device that has a boom and is built into a crane that transports suspended loads.
    An acquisition unit that acquires a tipping moment that is a moment acting on the boom based on the load of the suspended load and includes a forward moment and a lateral moment as components.
    A control unit that performs overload prevention control including control of either stopping the operation of the boom or issuing an alarm when the forward moment included in the overturning moment is larger than the first threshold value. And, with overload protection device.
  2. 　前記制御部は、前記転倒モーメントが、前記第一閾値と対応付けて設定される第二閾値よりも大きい場合に、前記過負荷防止制御を実施する、請求項１に記載の過負荷防止装置。 The overload prevention device according to claim 1, wherein the control unit executes the overload prevention control when the overturning moment is larger than the second threshold value set in association with the first threshold value.
  3. 　前記第二閾値を、前記ブームが取り得る旋回角と対応付けて記憶する記憶部を、更に備える、請求項２に記載の過負荷防止装置。 The overload prevention device according to claim 2, further comprising a storage unit that stores the second threshold value in association with a turning angle that the boom can take.
  4. 　前記制御部は、前記クレーンのアウトリガに作用する接地反力に基づいて、前記クレーンが側方に関する過負荷状態であるか否かを判定する、請求項１～３の何れか一項に記載の過負荷防止装置。 The control unit according to any one of claims 1 to 3, wherein the control unit determines whether or not the crane is in a lateral overload state based on the ground contact reaction force acting on the outriggers of the crane. Overload protection device.
  5. 　前記制御部は、前記ブームが取り得る姿勢条件と対応付けて予め記憶した強度定格モーメントと、前記転倒モーメントとに基づいて、前記クレーンが強度に関する過負荷状態であるか否かを判定する、請求項４に記載の過負荷防止装置。 The control unit determines whether or not the crane is in an overloaded state with respect to strength based on the strength rated moment stored in advance in association with the posture condition that the boom can take and the overturning moment. Item 4. The overload prevention device according to item 4.
  6. 　ブームを有し、吊荷を搬送するクレーンに組み込まれる過負荷防止装置であって、
    　前記吊荷の荷重に基づいて前記ブームに作用するモーメントであって、前方モーメント及び側方モーメントを成分として含む転倒モーメントを取得する取得部と、
    　前記前方モーメントに基づいて、前記クレーンが前方に関する過負荷状態であるか否かを判定する第一判定部と、
    　前記クレーンが側方に関する過負荷状態であるか否かを判定する第二判定部と、
    　前記クレーンが強度に関する過負荷状態であるか否かを判定する第三判定部と、
    　前記第一判定部、前記第二判定部、及び前記第三判定部のうちの少なくとも一つの判定部の判定結果が、過負荷状態であった場合に、前記ブームの動作を停止する制御及び警報を発する制御の少なくとも一方の制御を含む過負荷防止制御を実施する制御部と、を備える、
    　過負荷防止装置。     An overload prevention device that has a boom and is built into a crane that transports suspended loads.
    An acquisition unit that acquires a tipping moment that is a moment acting on the boom based on the load of the suspended load and includes a forward moment and a lateral moment as components.
    A first determination unit that determines whether or not the crane is in an overloaded state with respect to the front based on the forward moment.
    A second determination unit that determines whether or not the crane is in a lateral overload state, and
    A third determination unit that determines whether the crane is in an overloaded state with respect to strength, and
    A control and an alarm for stopping the operation of the boom when the determination result of at least one of the first determination unit, the second determination unit, and the third determination unit is in an overload state. A control unit that implements overload prevention control including control of at least one of the controls that emits
    Overload prevention device.
  7. 　前記第二判定部は、前記クレーンのアウトリガに作用する接地反力に基づいて、前記クレーンが、側方に関する過負荷状態であるか否かを判定し、
    　前記第三判定部は、前記転倒モーメントに基づいて、前記クレーンが、強度に関する過負荷状態であるか否かを判定する、請求項６に記載の過負荷防止装置。     The second determination unit determines whether or not the crane is in a lateral overload state based on the ground contact reaction force acting on the outriggers of the crane.
    The overload prevention device according to claim 6, wherein the third determination unit determines whether or not the crane is in an overload state with respect to strength based on the overturning moment.
PCT/JP2020/040715 2019-10-29 2020-10-29 Overload prevention device WO2021085569A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08119582A (en) * 1994-10-27 1996-05-14 Komatsu Ltd Overturning alarm device of working vehicle and overturning preventing method
JP2007314257A (en) * 2006-05-23 2007-12-06 Tadano Ltd Stability limit monitoring device of mobile crane having cargo bed
JP2008105817A (en) * 2006-10-26 2008-05-08 Tadano Ltd Fall-down preventive device for on-vehicle crane
JP2017206384A (en) * 2016-03-10 2017-11-24 マニトワック・クレーン・グループ・フランス・ソシエテ・パール・アクシオン・サンプリフィエＭａｎｉｔｏｗｏｃ Ｃｒａｎｅ Ｇｒｏｕｐ Ｆｒａｎｃｅ ＳＡＳ Method for ascertaining load capacity of crane, and crane

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08119582A (en) * 1994-10-27 1996-05-14 Komatsu Ltd Overturning alarm device of working vehicle and overturning preventing method
JP2007314257A (en) * 2006-05-23 2007-12-06 Tadano Ltd Stability limit monitoring device of mobile crane having cargo bed
JP2008105817A (en) * 2006-10-26 2008-05-08 Tadano Ltd Fall-down preventive device for on-vehicle crane
JP2017206384A (en) * 2016-03-10 2017-11-24 マニトワック・クレーン・グループ・フランス・ソシエテ・パール・アクシオン・サンプリフィエＭａｎｉｔｏｗｏｃ Ｃｒａｎｅ Ｇｒｏｕｐ Ｆｒａｎｃｅ ＳＡＳ Method for ascertaining load capacity of crane, and crane

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