JP6158723B2 - Suspension load calculation device - Google Patents

Description

  The present invention relates to a suspended load calculation device that calculates a load of a suspended load.

  2. Description of the Related Art A telescopic boom crane that detects the lifting load of a crane by detecting the pressure of a hoisting cylinder is known (see Patent Document 1). In Patent Document 1, an output corresponding to the difference between the non-rod side cylinder pressures of the undulating cylinders detected during the up direction operation and the down direction operation at the same inclination angle is generated. A technique for canceling hysteresis caused by the configuration of a hydraulic circuit by adding or subtracting is described.

JP 59-227692 A

  The technique described in Patent Document 1 is a technique for measuring the crane's suspension load by detecting the pressure of the hoisting cylinder in a crane having a telescopic boom in which the boom is hoisted by the hoisting cylinder. On the other hand, in the technique of measuring the hanging load in a crane that raises and lowers the lattice boom with the hoisting rope, the tension of the hoisting rope is detected, and the hoisting load is obtained based on the detection result. However, when determining the suspension load based on the tension of the hoisting rope, the influence of the friction between the hoisting rope and the sheave and the influence of the fleet angle due to the change in the distance between the fixed sheave and the moving sheave It will appear in the detection result. As a result, the output value of the suspension load may change according to the change in the boom undulation angle.

The suspension load calculating device according to claim 1 is an angle detection device that detects a boom raising / lowering angle, a tension detection device that detects a tension acting on a hoisting rope that raises or lowers the boom, and a hoisting motion that detects a boom hoisting operation. comprising a motion detection device, and a calculator for calculating a load of the suspended load, a storage device for storing correction coefficient used for correction of the tension acting on the hoist cable, a correction factor is provided in accordance with the derricking angle of the boom The computing unit acts on the hoisting rope detected by the tension detecting device based on the detection result of the hoisting motion by the hoisting motion detecting device and the correction coefficient corresponding to the boom hoisting angle detected by the angle detecting device. and correcting unit for correcting the tension, the rope hanging number of hoist cable set by the operator, on the basis of the tension which is calculated by multiplying the tensile force acting on the hoisting ropes corrected by the correction unit, Ri and a load calculating section for calculating a load of the load.
The suspension load calculation device according to claim 2 is the suspension load calculation device according to claim 1, wherein the calculation unit responds to the boom lifting angle when the standing motion is detected by the lifting motion detection device. When the tension acting on the hoisting rope is detected, the detected tension is stored in the storage device as the first reference tension, and the hoisting motion is detected by the hoisting motion detecting device, the hoisting rope according to the hoisting angle of the boom A reference tension setting unit that detects the tension acting on the storage device and stores the detected tension in the storage device as the second reference tension; calculates a correction coefficient based on the first reference tension and the second reference tension; It has a correction coefficient setting unit to be stored, the.
The suspension load calculation device according to claim 3 is the suspension load calculation device according to claim 2, wherein the correction coefficient setting unit is configured such that the corrected tension is an intermediate value between the first reference tension and the second reference tension. The correction coefficient is calculated so that
The suspension load calculation device according to claim 4 is the suspension load calculation device according to claim 3, wherein the correction coefficient setting unit is based on the first reference tension and the second reference tension, and the correction coefficient is calculated from the following equation. Is calculated.


The suspension load calculation device according to claim 5 is the suspension load calculation device according to any one of claims 1 to 4, wherein the correction unit is configured to detect the standing motion by the undulation motion detection device. The correction coefficient is multiplied by the tension detected by the tension detection device to obtain the corrected tension. When the undulation motion detection device detects the overturning motion, the reciprocal of the correction coefficient is detected by the tension detection device. The corrected tension is multiplied by the tension.

  According to the present invention, the accuracy of the output value of the suspended load can be increased.

The external appearance side view of the crane provided with the hanging load calculating apparatus which concerns on this Embodiment. The figure which looked at the gantry of FIG. 1 from the A direction. The figure which looked at the gantry of FIG. 1 from the B direction. The schematic diagram for demonstrating the winding method of the hoisting rope with respect to a lower sheave and an upper sheave. (A) is a schematic diagram which shows the state where the distance between a lower sheave group and an upper sheave group is the longest, (b) is a schematic diagram which shows the state where the distance between a lower sheave group and an upper sheave group is the shortest. The block diagram which shows the control system of the overload prevention apparatus mounted in a crane. The figure which shows an example of a rated load curve. The table | surface which shows the correction coefficient provided according to the boom angle. The figure which shows the relationship between the tension | tensile_strength detected with a load cell, and the boom raising / lowering angle. The flowchart which shows an example of the operation | movement of the process by the correction coefficient setting program performed by a controller. The flowchart which shows an example of the operation | movement of the process by the hanging load calculation program performed by a controller. 12 is a flowchart showing a tension correction process of FIG. 11. The figure which shows the relationship between the tension | tensile_strength detected by a load cell, and the boom raising / lowering angle in the crane from which boom length differs.

Hereinafter, an embodiment of a suspension load calculation device according to the present invention will be described with reference to the drawings.
FIG. 1 is an external side view of a crawler crane as an example of a construction machine provided with a suspension load calculation device according to an embodiment of the present invention. In the following, the vertical and vertical directions are defined with reference to the work posture of FIG.

  The crane 100 includes a traveling body 101, a revolving body 102 that is turnably provided on the traveling body 101 via a turning wheel, and a lattice boom (hereinafter simply referred to as a boom 103) that is pivotally supported by the revolving body 102. To be included). A driver's cab 105 is provided at the front part of the swing body 102, and a counterweight device 120 is attached to the rear part of the swing body 102.

  The boom 103 is pivotally supported by the frame of the revolving structure 102 at the base end (not shown) at the side of the cab 105. Three drums are disposed in the housing 113 of the revolving structure 102. The three drums are attached in the order of the front drum 201, the rear drum 202, and the undulating drum 203 from the front to the rear. A hook 108 is suspended from a tip of the boom 103 by a hook rope 107. One end of the hook rope 107 is fixed to the front drum 201, and the hook rope 107 is wound around the front drum 201 or fed out from the front drum 201 by the rotation of the front drum 201. As a result, the hook 108 held on the other end side of the hook rope 107 moves up and down with respect to the distal end portion of the boom 103.

  On the revolving structure 102, the gantry 200 is mounted so as to be able to rise and fall with respect to the revolving structure 102. The gantry 200 includes a front leg member 210, a rear leg member 220, and a lower spreader 230 fixed to the upper end side of the front leg member 210. A base end portion 213 of the front leg member 210 is rotatably connected to a bracket 102 a (see FIG. 3) provided at the center of the revolving structure 102. The base end portion of the rear leg member 220 is rotatably connected to a bracket 102b (see FIG. 3) provided on the rear side of the revolving structure 102. The gantry 200 is raised and laid down by the expansion and contraction of the hydraulic cylinder 204.

  The lower spreader 230 includes a lower sheave group 231 composed of a plurality of lower sheaves. An upper spreader 160 is interposed between the lower spreader 230 and the tip of the boom 103. The upper spreader 160 includes an upper sheave group 161 composed of a plurality of upper sheaves. The hoisting rope 112 is wound around the upper sheave group 161 of the upper spreader 160 and the lower sheave group 231 of the lower spreader 230 a plurality of times.

  The upper spreader 160 is connected to the other end of a pendant rope 110 having one end fixed to the tip of the boom 103. The hoisting rope 112 having one end fixed to the hoisting drum 203 is connected to the load cell 281 attached to the lower spreader 230 at the other end. The load cell 281 side is the fixed end of the hoisting rope 112. When the hoisting rope 112 is wound or fed out by the rotation of the hoisting drum 203, the distance between the lower spreader 230 and the upper spreader 160 is changed, and the boom 103 is raised and lowered via the hoisting rope 112.

  The rear drum 202 is used for raising and lowering the auxiliary hook and raising and lowering the jib boom, but is illustrated as a state not used in FIG.

  FIG. 2 is a view of the gantry 200 of FIG. 1 as viewed from the direction A, and FIG. 3 is a view of the gantry 200 of FIG. As shown in FIG. 2, the front leg member 210 of the gantry 200 includes a pair of front leg frames 211 and an upper frame 212 that connects the pair of front leg frames 211 at the upper part of the front leg frame 211. The base end portion 213 of each front leg frame 211 is connected to a bracket 102a (see FIG. 3) provided on the revolving body 102 by a pin, and the front leg member 210 is rotatably connected to the revolving body 102. As shown in FIG. 3, a load cell 281 is attached on the upper frame 212 of the front leg member 210.

  As shown in FIG. 2, the lower spreader 230 includes a pair of support frames 232, a support shaft 233 spanned between the support frames 232 on the upper end side of the pair of support frames 232, and the support spreader 233 is rotatable. And a lower sheave group 231 attached thereto. The lower ends of the pair of support frames 232 are fixed to the upper frame 212 of the front leg member 210.

  The width of the lower spreader 230 is smaller than the width of the front leg member 210. In other words, the length between the pair of support frames 232 of the lower spreader 230 is smaller than the length between the pair of front leg frames 211 of the front leg member 210.

  As shown in FIGS. 2 and 3, a plurality of (six in the example of the present embodiment) lower sheaves 231 a to 231 f are rotatably supported by the support shaft 233 on the lower spreader 230. A plurality (five in the example of the present embodiment) of upper sheaves 161a to 161e (see FIG. 4) are rotatably supported on the support shaft 162 (see FIGS. 1 and 4).

  As shown in FIGS. 1 and 4, the support shaft 233 of the lower spreader 230 and the support shaft 162 of the upper spreader 160 are arranged in parallel with the rotation shaft (not shown) of the hoisting drum 203. That is, the lower sheaves 231a to 231f and the upper sheaves 161a to 161e are so-called vertical sheaves.

  FIG. 4 is a schematic diagram for explaining a method of hanging the hoisting rope 112 around the lower sheaves 231a to 231f and the upper sheaves 161a to 161e. The hoisting rope 112 fed out from the hoisting drum 203 is first wound around the lower sheave 231b arranged at the second position from one end of the lower sheave group 231. The hoisting rope 112 hung around the lower sheave 231b is hung around the upper sheave 161a arranged at the first position of one end of the upper sheave group 161 on the same side as one end of the lower sheave group 231. The hoisting rope 112 hung around the upper sheave 161 a is hung around the lower sheave 231 a arranged at the most end side in the lower sheave group 231. The hoisting rope 112 hung around the lower sheave 231a is hung around the upper sheave 161b arranged second from one end in the upper sheave group 161. The hoisting rope 112 hung on the upper sheave 161b is hung on the lower sheave 231c arranged third from the one end in the lower sheave group 231. The hoisting rope 112 hung around the lower sheave 231c is hung around the upper sheave 161c arranged third from the one end in the upper sheave group 161.

  Hereinafter, similarly, the hoisting rope 112 is wound around the sheaves arranged in the lower sheave group 231 and the upper sheave group 161 alternately in turn on the sheave adjacent to the other end side. That is, after the hoisting rope 112 is hung on the upper sheave 161c, it is hung in the order of the lower sheave 231d, the upper sheave 161d, the lower sheave 231e, the upper sheave 161e, and the lower sheave 231f. The hoisting rope 112 hung around the lower sheave 231f is fixed to the load cell 281.

  FIG. 5A is a schematic diagram showing a state in which the distance between the lower sheave group 231 and the upper sheave group 161 is the longest, and FIG. 5B is a diagram between the lower sheave group 231 and the upper sheave group 161. It is a schematic diagram which shows a state with the shortest distance. As shown in FIGS. 5A and 5B, the fleet angle, which is the angle of the undulating rope 112 between the lower sheaves 231c to 231f and the upper sheaves 161b to 161e, is the lower sheave group 231 and the upper sheave. It changes depending on the distance between the groups 161. For example, the fleet angle α of the hoisting rope 112 between the lower sheave 231e and the upper sheave 161d is the minimum angle when the distance between the lower sheave group 231 and the upper sheave group 161 shown in FIG. αmin, and the maximum angle αmax is obtained when the distance between the lower sheave group 231 and the upper sheave group 161 shown in FIG.

  That is, when the boom 103 is raised, the fleet angle α gradually increases as the upper sheave group 161 that is the moving sheave approaches the lower sheave group 231 that is the fixed sheave. When the boom 103 is laid down, the fleet angle α gradually decreases as the upper sheave group 161 moves away from the lower sheave group 231.

  FIG. 6 is a block diagram showing a control system of the overload prevention device mounted on the crane. The overload prevention device includes a controller 300 that includes an arithmetic processing unit having a CPU and a storage device such as ROM and RAM, and other peripheral circuits.

  FIG. 7 is a diagram illustrating an example of a rated load curve. The storage device of the controller 300 stores a plurality of data tables of rated load curves as shown in FIG. 7 which are the relationship between the working radius r and the rated total load Wa. The rated total load Wa is a limit value of a load that can be lifted at the working radius r, and is set to prevent the crane 100 from overturning or breakage of components. Each data table is provided for each boom 103 length (boom type). When the boom length is set by the operator using the input unit 311 (see FIG. 6), a data table corresponding to the set boom 103 length is read according to a signal from the input unit 311.

  As shown in FIG. 6, a boom angle sensor 131, a load cell 281, a rotation sensor 313, an input unit 311, an operation amount sensor 312, an alarm device 321, a stop device 322, and a display unit 323 are connected to the controller 300. Has been. The boom angle sensor 131 is attached to the base end side of the boom 103 (see FIG. 1), detects the undulation angle of the boom 103 (hereinafter also referred to as a boom angle), and outputs a control signal corresponding to the detected undulation angle. Output to the controller 300. The boom angle sensor 131 detects, for example, a ground angle that is an angle with respect to a horizontal plane as an undulation angle of the boom 103 (hereinafter also referred to as a boom angle).

  The load cell 281 detects the tension acting on the hoisting rope 112 for hoisting the boom 103 and outputs a control signal corresponding to the detected tension to the controller 300. The input unit 311 is a touch panel, for example, and outputs a control signal corresponding to an operation from the operator to the controller 300. The operator can set the multiplier NB of the hoisting rope 112, the boom length, the hook weight, and the like by operating the input unit 311.

  The rotation sensor 313 is, for example, a rotary encoder, detects the rotation direction of the undulation drum 203, and outputs a control signal corresponding to the detected rotation direction to the controller 300. The operation amount sensor 312 is, for example, a lowering operation between a pilot pressure sensor provided in a pilot line on the raising operation side between the hydraulic pilot type operation lever and the direction control valve, and between the hydraulic pilot type operation lever and the direction control valve. It is comprised by the pilot pressure sensor provided in a side pilot pipe line. The operation amount sensor 312 detects the operation amount of the hydraulic pilot type operation lever, and outputs a control signal corresponding to the detected operation amount to the controller 300.

  The display unit 323 is, for example, a touch panel display that is also used as the input unit 311, and displays suspension load information and work posture information on the display screen based on a control signal output from the controller 300. The alarm device 321 generates an alarm based on a control signal output from the controller 300.

  The stop device 322 stops driving hydraulic motors (not shown) connected to the drums 201 to 203 based on a control signal output from the controller 300. Stop device 322 is, for example, an electromagnetic switching valve provided in a pilot line between a hydraulic pilot type operation lever and a directional control valve that operates according to the operation amount of this operation lever. When the electromagnetic switching valve is controlled to the fully open position, the directional control valve operates according to the operation amount of the operation lever, and the hydraulic oil is supplied from the hydraulic pump to the hydraulic motor via the directional control valve. The motor is driven.

  When the controller 300 controls the electromagnetic switching valve to the fully closed position, the pressure oil supplied to the pilot portion of the direction control valve is shut off even when the operation lever is operated. As a result, the pressure oil supplied from the hydraulic pump to the hydraulic motor via the direction control valve is shut off, and the drive of the hydraulic motor is stopped.

  The controller 300 includes an undulation determination unit 301, a correction unit 302, a load calculation unit 303, a winch control unit 304, a display control unit 305, a reference tension setting unit 306, a correction coefficient setting unit 307, a boom operation direction. The determination unit 308 is functionally provided.

  When the rotation sensor 313 detects that the hoisting drum 203 is rotating in one direction, the hoisting determination unit 301 determines that the boom 103 is standing up, that is, a boom raising operation is being performed. To do. When the rotation sensor 313 detects that the hoisting drum 203 is rotating in the other direction, the hoisting determination unit 301 determines that the boom 103 is in a tilting operation, that is, a boom lowering operation is being performed. To do.

  The boom operation direction determination unit 308 determines that the boom raising operation is performed when the operation amount sensor 312 detects a raising side operation amount equal to or greater than a predetermined value. The boom operation direction determination unit 308 determines that the boom lowering operation is being performed when the operation amount sensor 312 detects a lower operation amount that is equal to or greater than a predetermined value.

FIG. 8 is a table showing correction coefficients provided according to the boom angle. As shown in FIG. 8, the storage device of the controller 300 stores a correction coefficient H _m used for correcting the tension acting on the hoisting rope 112 according to the hoisting angle θb _m of the boom 103. Here, “m” in H _m and θb _m represents an integer from 1 to n, and n corresponds to the number of correction coefficients in the table shown in FIG.

The correction unit 302 illustrated in FIG. 6 is detected by the load cell 281 based on the determination result of the undulation operation by the undulation determination unit 301 and the correction coefficient H _m corresponding to the boom angle θb _m detected by the boom angle sensor 131. The tension acting on the hoisting rope 112 (hereinafter also referred to as rope tension Tr) is corrected.

The correction unit 302 selects θb _m closest to the detected boom angle θb from θb _m in the table of FIG. 8, and selects a correction coefficient H _m corresponding to the selected boom angle θb _m .

Correction unit 302, when it by undulating determination unit 301 is in the standing operation is determined multiplies the correction coefficient H _m in rope tension Tr, the corrected tension (hereinafter, also referred to as a correction tension Th ). That is, the corrected tension Th is calculated by the following equation (1).
Th = Tr × H _m (1)

Correction unit 302, when it by undulating determination unit 301 is in lodging operation is determined multiplies the reciprocal 1 / H _m of the correction coefficient in rope tension Tr, the correction tension Th. That is, the correction tension Th is calculated by the following equation (2).
Th = Tr × 1 / H _m (2)

  The load calculation unit 303 calculates the working radius r based on the boom angle θb detected by the boom angle sensor 131 and the boom length input by the input unit 311. The load calculation unit 303 determines the actual load of the suspended load (hereinafter referred to as the suspended load W) based on the corrected tension Th calculated by the correction unit 302 and the rope multiplier NB set by the input unit 311 operated by the operator. To calculate).

  The winch control unit 304 determines whether or not the calculated suspension load W is smaller than the rated total load Wa at the calculated work radius r. The winch control unit 304 outputs a stop signal to the stop device 322 and outputs an alarm signal to the alarm device 321 when the suspended load W is equal to or greater than the rated total load Wa. When a stop signal is input to the stop device 322, the stop device 322 stops driving of the hydraulic motors connected to the drums 201 to 203. When an alarm signal is input to the alarm device 321, the alarm device 321 generates an alarm.

  For example, in a crane operation, when a stop signal is output from the winch control unit 304 to the stop device 322 while the boom 103 is lying down, the drive of a hydraulic motor (not shown) coupled to the hoisting drum 203 is stopped, and the boom The lodging operation 103 stops automatically.

  The display control unit 305 controls an image displayed on the display screen of the display unit 323. The display control unit 305 displays the suspension load W calculated by the load calculation unit 303 on the display screen of the display unit 323.

  The reference tension setting unit 306 detects the rope tension Tr corresponding to the boom angle θb and determines the detected rope tension Tr as the first reference tension when it is determined by the undulation determination unit 301 that the standing motion is being performed. It is stored in the storage device as T1. The reference tension setting unit 306 detects the rope tension Tr according to the boom angle θb and determines the detected rope tension Tr as the second reference tension when it is determined by the undulation determination unit 301 that the body is in the overturning operation. It is stored in the storage device as T2. The first reference tension T1 and the second reference tension T2 are set by performing a standing operation and a lying operation under the same suspension load, for example, an empty hook state. The first reference tension T1 and the second reference tension T2 are used for calculating a correction coefficient described later.

  FIG. 9 is a diagram showing the relationship between the rope tension detected by the load cell 281 and the undulation angle of the boom 103. The characteristic BU shown in FIG. 9 is a characteristic indicating the rope tension Tr detected by the load cell 281 during the boom raising operation, that is, during the standing operation of the boom 103 in the state of the empty hook in which the suspended load is not attached to the hook 108. is there. A characteristic BD shown in FIG. 9 is a characteristic indicating the rope tension Tr detected by the load cell 281 during the boom lowering operation, that is, during the fall operation of the boom 103 in a state of an empty hook in which the suspended load is not attached to the hook 108. . In the rope tension Tr detected by the load cell 281, hysteresis is generated due to the friction of the sheaves 161 a to 161 e and 231 a to 231 f as shown in the figure.

  As shown in the figure, the rope tension Tr during the standing operation and the rope tension Tr during the falling operation do not have the same value at the predetermined boom angle θb. This is because the rotation directions of the sheaves 161a to 161e and 231a to 231f on which the hoisting rope 112 is hung are different between the standing operation and the tilting operation, so that the sheaves 161a to 161e, 231a to 231f and the hoisting rope 112 are between The main cause is estimated to be a difference in the magnitude of the generated frictional force.

  Further, the ratio of the change amount of the rope tension to the change amount of the boom angle (hereinafter simply referred to as a change rate), that is, the inclination is also different between the characteristic BU and the characteristic BD. Thus, the difference in change rate appears when the distance between the lower sheave group 231 and the upper sheave group 161 is reduced between the standing operation and the lying operation, that is, when the fleet angle α is increased (see FIG. 5 (a) → see FIG. 5 (b)) and when the distance between the lower sheave group 231 and the upper sheave group 161 is extended, that is, when the fleet angle α is reduced (FIG. 5 (b) → FIG. 5 ( It is estimated that the main cause is that there is a difference in the magnitude of the frictional force generated between the sheaves 161a to 161e, 231a to 231f and the hoisting rope 112.

In this embodiment, at the time of standing operation of the boom 103 and at the time of lodging operation, in order to suppress the influence of difference in change characteristics of the rope tension in accordance with the boom angle, using the correction coefficient H _m, it is detected The rope tension Tr was corrected and output as the corrected tension Th.

The correction coefficient is set in advance by the correction coefficient setting unit 307 shown in FIG. Correction coefficient setting unit 307, the first reference tension T1 and the second reference tension T2 by the reference tension setting unit 306 is set, calculates a correction coefficient H _m based on the first reference tension T1 and the second reference tension T2 To do. The correction coefficient setting unit 307 calculates the correction coefficient H _m from Equation (3) so that the corrected tension becomes an intermediate value (the one-dot chain line in FIG. 9) between the first reference tension T1 and the second reference tension T2. Calculate and store in the storage device. T1 (θb _m ) and T2 (θb _m ) are detected and stored for each boom angle θb _m (m = 1, 2,..., N−1, n), respectively. It is tension. H _m is a correction coefficient calculated at a predetermined boom angle θb _m .

As described above, in the present embodiment, the controller 300 functionally includes the reference tension setting unit 306 and the correction coefficient setting unit 307. Therefore, the correction coefficient H is set at the time of factory shipment or when the boom 103 is replaced. _m can be set easily.

  FIG. 10 is a flowchart showing an example of processing operation by the correction coefficient setting program executed by the controller 300. The processing shown in this flowchart is started, for example, when an operation for executing correction coefficient setting guidance is performed on the input unit 311.

  As shown in FIG. 10, in step S101, the controller 300 causes the display unit 323 to display a message “Please make an empty hook” and then the process proceeds to step S103. In step S103, the controller 300 determines whether or not the operator has performed a work completion operation for instructing the input unit 311 that the work on the empty hook has been completed. If an affirmative determination is made in step S103, the controller 300 determines that it is in an empty hook state and proceeds to step S106. If a negative determination is made in step S103, the controller 300 determines that it is not in an empty hook state and returns to step S101. The empty hook determination process in step S103 determines that the empty hook state is present when the tension detected by the load cell 281 is less than the threshold value stored in the storage device in advance, and the tension detected by the load cell 281 exceeds the threshold value. Sometimes it may be determined that the hook is not empty.

  In step S106, the controller 300 causes the display unit 323 to output a message “Please lower the boom until it stops at the lower limit”, and proceeds to step S111. In step S111, the controller 300 determines whether the hoisting angle of the boom 103 has reached the lower limit position, that is, whether the boom angle θb is smaller than the angle corresponding to the lower limit position. If a positive determination is made in step S111, the process proceeds to step S113, and if a negative determination is made, the process returns to step S106.

  In step S113, the controller 300 outputs a stop signal to the stop device 322, stops driving of the hydraulic motor (not shown) of the hoisting drum 203, and proceeds to step S116.

  In step S116, the controller 300 causes the display unit 323 to display a message “Please roll up at a slow speed”, and then proceeds to step S118. In step S118, the controller 300 determines whether or not a boom raising operation has been performed by the operation lever. If a positive determination is made in step S118, the process proceeds to step S120, and if a negative determination is made, the process returns to step S116.

  In step S120, the controller 300 outputs a stop release signal to the stop device 322 to release the drive stop of the hydraulic motor (not shown) of the hoisting drum 203, and proceeds to step S121.

  In step S121, the controller 300 determines whether or not the undulation angle of the boom 103 has reached a predetermined angle corresponding to the upper limit position, that is, whether or not the boom angle θb is larger than the angle corresponding to the upper limit position. If a negative determination is made in step S121, the process proceeds to step S126, and if a positive determination is made, the process proceeds to step S131.

In step S126, the controller 300 reads the information on the boom angle θb detected by the boom angle sensor 131 and the information on the rope tension Tr acting on the hoisting rope 112 detected by the load cell 281 and stores them in the storage device. The process returns to step S121. This storage process is executed for each Δθ in a state where the boom angle θb is in the range of θb ₁ to θb _n . For example, the rope tension Tr when θb ₁ = 30 degrees is stored in the storage device as the first reference tension T1 (θb ₁ ), and the tension Tr when θb ₂ = 35 degrees is stored in the first reference tension T1 (θb ₂ ). Is stored in the storage device. Every Δθ = 5 degrees, the detected rope tension Tr up to θb ₃ , θb ₄ ... Θb ₁₁ = 80 degrees is used as the first reference tension T1 (θb ₃ ), T1 (θb ₄ )... T1 (θb ₁₁ ) To be stored in the storage device.

  In step S131, the controller 300 outputs a stop signal to the stop device 322, stops driving of the hydraulic motor (not shown) of the hoisting drum 203, and proceeds to step S136.

  In step S136, the controller 300 causes the display unit 323 to display a message “please roll it down at a slow speed”, and then proceeds to step S138. In step S138, the controller 300 determines whether or not a boom lowering operation has been performed by the operation lever. If a positive determination is made in step S138, the process proceeds to step S140, and if a negative determination is made, the process returns to step S136.

  In step S140, the controller 300 outputs a stop release signal to the stop device 322, cancels the drive stop of the hydraulic motor (not shown) of the hoisting drum 203, and proceeds to step S141.

  In step S141, the controller 300 determines whether the hoisting angle of the boom 103 has reached the lower limit position, that is, whether the boom angle θb is smaller than the angle corresponding to the lower limit position. If a negative determination is made in step S141, the process proceeds to step S146, and if a positive determination is made, the process proceeds to step S151.

In step S146, the controller 300 reads the information on the boom angle θb detected by the boom angle sensor 131 and the information on the rope tension Tr acting on the hoisting rope 112 detected by the load cell 281 and stores them in the storage device. The process returns to step S141. This storage process is executed for each Δθ in a state where the boom angle θb is in the range of θb _n to θb ₁ . For example, the rope tension Tr when θb ₁₁ = 80 degrees is stored in the storage device as the second reference tension T2 (θb ₁₁ ), and the rope tension Tr when θb ₁₀ = 75 degrees is stored in the second reference tension T2 (θb ₁₀ ) To be stored in the storage device. Every Δθ = 5 degrees, the detected rope tension Tr up to θb ₉ , θb ₈ ... Θb ₁ = 30 degrees is used as the second reference tension T2 (θb ₉ ), T2 (θb ₈ )... T2 (θb ₁ ) To be stored in the storage device.

In step S151, the controller 300 outputs a stop signal to the stop device 322, stops driving of the hydraulic motor (not shown) of the hoisting drum 203, and proceeds to step S161. In step S161, the controller 300 calculates the correction coefficient H _m (m = 1, 2,..., N−1, n) from the above-described equation (3), stores it in the storage device, and FIG. The processing shown in FIG.

  An operator's work performed in accordance with the processing of the correction coefficient setting program will be described. When the operator performs an operation for executing the correction coefficient setting guidance on the input unit 311, a message “please make an empty hook” is displayed on the display unit 323 (step S <b> 101).

  When the suspended load is suspended from the hook 108, the operator removes the suspended load from the hook 108 according to the message and performs an operation completion operation on the input unit 311. When the operation completion operation is performed, a message “Please lower the boom until it stops at the lower limit” is displayed on the display unit 323 (steps S103 → S106).

  When the boom 103 is not in the lower limit position, the operator operates the boom operation lever downward according to the message to cause the boom 103 to fall down. When the boom 103 falls down to the lower limit position, the boom 103 automatically stops and a message “Please roll up at a slow speed” is displayed on the display unit 323 (steps S111 → S113 → S116).

The operator operates the boom operation lever to the up side according to the message, and slowly raises the boom 103 (steps S118 → S120). During the standing motion of the boom 103, the rope tension Tr detected by the load cell 281 is acquired every predetermined control cycle, and when the predetermined undulation angle θb _m (m is an integer from 1 to n) is reached. The rope tension Tr is stored in the storage device as the first reference tension T1 (θb _m ) (steps S121 → S126). The first reference tension T1 (θb _m ) is set, for example, every time the undulation angle of the boom 103 changes 5 degrees from 30 degrees to 80 degrees.

  When the boom 103 stands up to the upper limit position, the boom 103 automatically stops and a message “Please lower at a slow speed” is displayed on the display unit 323 (steps S121 → S131 → S136).

In accordance with the message, the operator operates the boom operation lever to the lower side, and slowly lowers the boom 103 (steps S138 → S140). During the tilting operation of the boom 103, the rope tension Tr detected by the load cell 281 is acquired every predetermined control period, and when the predetermined undulation angle θb _m (m is an integer from 1 to n) is reached. The rope tension Tr is stored in the storage device as the second reference tension T2 (θb _m ) (steps S141 → S146). The second reference tension T2 is set, for example, every time the undulation angle of the boom 103 changes 5 degrees from 80 degrees to 30 degrees.

When the boom 103 falls down to the lower limit position, the boom 103 automatically stops (steps S141 → S151). As described above, the rope tension Tr during the standing operation of the boom 103 is set as the first reference tension T1 (θb _m ), and the rope tension Tr during the fall operation of the boom 103 is set as the second reference tension T2 (θb _m ). When set, the correction coefficient H _m (m = 1, 2,..., N−1, n) is based on the first reference tension T1 (θb _m ) and the second reference tension T2 (θb _m ). The table shown in FIG. 8 is calculated and stored in the storage device (step S161).

  FIG. 11 is a flowchart showing an example of processing operation by the suspension load calculation program executed by the controller 300. When an ignition switch (not shown) is turned on, a program for performing the processing shown in FIG. 11 is started, and the processing after step S200 is repeatedly executed by the controller 300 at every predetermined control cycle.

  In step S <b> 200, the controller 300 detects the rope tension Tr acting on the hoisting rope 112 detected by the load cell 281, information about the boom angle θb detected by the boom angle sensor 131, and information set by the input unit 311 (boom length). , The hook weight, the number of hooks NB), and the information on the movement direction of the boom 103 detected by the rotation sensor 313, and the process proceeds to step S300.

  In step S300, the controller 300 corrects the rope tension Tr acquired in step S200, that is, calculates the corrected tension Th, and proceeds to step S390. In step S390, the controller 300 calculates the tension Tp acting on the pendant rope 111 by multiplying the rope multiplication number NB acquired in step S200 by the correction tension Th calculated in step S300, and proceeds to step S400.

  In step S400, the controller 300 acts in the vertical direction by subtracting a tension corresponding to the load (excluding the suspended load) of the front working unit including the boom 103 and the hook 108 from the tension Tp calculated in step S390. The suspension load W is calculated, and the process proceeds to step S410. Note that the tension corresponding to the load on the front working unit is stored in advance in the storage device in accordance with the boom angle θb. A plurality of these characteristics are stored in accordance with the boom length and hook weight set by the input unit 311.

  In step S410, the controller 300 calculates the working radius r based on the boom angle θb acquired in step S200 and the boom length, and proceeds to step S420. In step S420, the controller 300 refers to the data table of the rated load curve stored in the storage device, calculates the rated total load Wa based on the working radius r calculated in step S410, and proceeds to step S430.

  In step S430, the controller 300 compares the suspended load W calculated in step S400 with the rated total load Wa calculated in step S420, and determines whether the suspended load W is smaller than the rated total load Wa. If an affirmative determination is made in step S430, the process proceeds to step S440, and if a negative determination is made, the process proceeds to step S450.

  In step S440, the controller 300 outputs a control signal that deactivates the stop device 322 to the stop device 322, and returns to step S200. When stop device 322 is, for example, an electromagnetic switching valve provided in a pilot line between an operation lever and a direction control valve that operates in accordance with an operation amount of the operation lever, as described above, in step S440. The controller 300 outputs a signal for fully opening the electromagnetic switching valve to the electromagnetic switching valve.

  In step S450, the controller 300 outputs a control signal for operating the stop device 322 to the stop device 322, and returns to step S200. When stop device 322 is, for example, an electromagnetic switching valve provided in a pilot line between an operation lever and a direction control valve that operates in accordance with an operation amount of the operation lever, as described above, in step S440. The controller 300 outputs a signal for fully closing the electromagnetic switching valve to the electromagnetic switching valve. In the crane work, when the stop device 322 is activated during the operation of lowering the boom 103, the drive of the hydraulic motor (not shown) is stopped, and the operation of lowering the boom 103 is automatically stopped.

With reference to FIG. 12, the tension Tr correction process will be described. In step S310, the controller 300, a boom angle .theta.b acquired in step S200, by comparing the boom angle .theta.b _m of the correction coefficient table stored in the storage device (see FIG. 8), the detected boom angle .theta.b The boom angle θb _m that is the closest to the detected value, that is, the smallest difference from the detected value, is selected, and the process proceeds to step S320.

In step S320, the controller 300 reads the correction coefficient _{H m} which corresponds to the boom angle .theta.b _m selected in step S310, the process proceeds to step S330. In step S330, the controller 300 determines whether or not the boom 103 is standing up based on the information on the movement direction of the boom acquired in step S200, that is, the information on the rotation direction of the hoisting drum 203 detected by the rotation sensor 313. Determine whether. If an affirmative determination is made in step S330, the controller 300 determines that the boom 103 is standing up, that is, a boom raising operation, and proceeds to step S340. If a negative determination is made in step S330, the controller 300 determines that the boom 103 is in a lying down state, that is, a boom lowering operation, and proceeds to step S350.

In step S340, the controller 300, the rope tension Tr acquired in step S200, by multiplying the correction coefficient _{H m} read in step S320, obtains a correction tension Th, and terminates the correction process of FIG. 12, to Step S390 move on. In step S350, the controller 300, the rope tension Tr acquired in step S200, by multiplying the reciprocal 1 / _{H m} of the correction coefficient read in step S320, obtains a correction tension Th, and terminates the correction process of FIG. 12 The process proceeds to step S390.

As described above, in the present embodiment, the correction coefficient setting program shown in FIG. 10 is executed, so that the correction coefficient H is calculated by the equation (3) using the first and second reference tensions set in the empty hook state. _m is calculated and stored in the storage device. During crane operation, by hanging load computing program shown in FIG. 11 and FIG. 12 is executed, wherein using the correction coefficient H _m stored in the storage device (1), the correction tension Th by formula (2) The suspension load is calculated based on the corrected tension Th. For this reason, the corrected tension Th during crane operation is an intermediate value between the tension detected during the boom standing operation and the tension detected during the boom overturning operation, and the accuracy of the output value of the suspended load can be increased. .

According to the present embodiment described above, the following operational effects can be obtained.
(1) A correction coefficient used for correcting the tension Tr acting on the hoisting rope 112 is provided according to the hoisting angle of the boom 103. The controller 300 corrects the rope tension Tr based on the detection result of the hoisting movement and the correction coefficient corresponding to the hoisting angle of the boom, and calculates the load W of the suspended load based on the corrected tension Th. Thereby, the change of the output value of the suspension load W according to the change of the raising / lowering angle of the boom 103 can be suppressed. Since the accuracy of the output value of the suspended load W can be increased, the accuracy of the operation of the overload prevention device can be increased.

(2) When the standing motion is detected, the controller 300 detects the rope tension Tr according to the boom angle θb _m and stores the detected rope tension Tr as the first reference tension T1 (θb _m ). The function of detecting the rope tension Tr according to the boom angle θb _m and storing the detected tension Tr in the storage device as the second reference tension T2 (θb _m ) when the fall operation is detected. have. Further, the controller 300 has a function of calculating a correction coefficient H _m based on the first reference tension T1 (θb _m ) and the second reference tension T2 (θb _m ) and storing it in the storage device. Thus, factory and can be easily set the correction coefficient H _m replacement or the like of the boom 103.

  FIG. 13 is a diagram showing the relationship between the tension detected by the load cell 281 and the boom undulation angle in the crane 100 having different boom lengths. FIG. 13 shows the characteristics of a crane equipped with three types of booms, and all show the characteristics of an empty hook state. The boom raising characteristic BU1 and the boom lowering characteristic BD1 are characteristics in a crane having the longest boom length among the three types of booms. The boom raising characteristic BU3 and the boom lowering characteristic BD3 are characteristics in a crane having the shortest boom length among the three types of booms. The boom raising characteristic BU2 and the boom lowering characteristic BD2 are characteristics in a crane including a boom having an intermediate length among the three types of booms 103. As shown in the figure, when the boom length is different, the magnitude of the rope tension at a predetermined angle is different, and the rate of change (inclination) is also different.

In this embodiment, it is possible to set the correction coefficient H _m when replacing the boom 103, it is not necessary to store the correction coefficient H _m which corresponds to a plurality of types of booms in advance in the storage device. Therefore, it is possible to reduce the capacity of the storage device for storing the correction coefficient H _m.

(3) The controller 300 calculates the correction coefficient H _{m according} to Equation (3) so that the corrected tension becomes an intermediate value between the first reference tension T1 (θb _m ) and the second reference tension T2 (θb _m ). Is calculated. When the standing motion is detected, the controller 300 multiplies the detected rope tension Tr by the correction coefficient H _m as shown in the equation (1) to obtain the corrected tension Th, and the falling motion is detected. If it is, the corrected rope tension Tr is multiplied by the reciprocal 1 / H _m of the correction coefficient to obtain the corrected tension Th as shown in the equation (2). Thereby, the precision of the output value of the suspension load W at the time of crane work can be improved.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(Modification 1)
In the above-described embodiment, the controller 300 determines the undulation operation of the boom 103 based on the rotation direction information detected by the rotation sensor 313. However, the detection method of the undulation operation of the boom 103 is not limited to this. For example, it is determined that the boom 103 is standing up when the boom raising operation is performed by the boom operation lever, and the boom 103 is in the lying down operation when the boom lowering operation is performed by the boom operation lever. May be determined. A change in the raising / lowering angle of the boom 103 may be detected to determine whether the boom 103 is standing or moving.

(Modification 2)
In the above-described embodiment, the example in which the correction coefficient H _m is stored every Δθ = 5 degrees in the range of the boom angle θb _m of 30 degrees to 80 degrees has been described, but the present invention is not limited to this. . The value of Δθ may be less than 5 degrees or greater than 5 degrees. Although every 5 degrees correction coefficient H _m at equal intervals has been described the example that has been set, it may be set the correction coefficient H _m at unequal intervals.

(Modification 3)
In the above-described embodiment, the example in which the controller 300 functionally includes the reference tension setting unit 306 and the correction coefficient setting unit 307 has been described, but the present invention is not limited to this. The characteristic of the correction coefficient corresponding to the boom angle can be stored in advance in the storage device for each type of boom 103 (boom length). Note that the controller 300 functionally includes the reference tension setting unit 306 and the correction coefficient setting unit 307, so that it is possible to deal with variations in crane models or variations among cranes in the same model. This is preferable because it is possible.

(Modification 4)
In the above-described embodiment, the load calculation device in the overload prevention device mounted on the crawler crane has been described as an example, but the present invention is not limited to this. The present invention can be applied to various construction machines such as a stationary tower crane that calculates and uses the load of a suspended load.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

  DESCRIPTION OF SYMBOLS 100 Crane, 101 traveling body, 102 revolving body, 102a bracket, 102b bracket, 103 boom, 105 cab, 107 hook rope, 108 hook, 110 pendant rope, 111 pendant rope, 112 hoisting rope, 113 housing, 120 counterweight device 131, boom angle sensor, 160 upper spreader, 161 upper sheave group, 162 support shaft, 200 gantry, 201 front drum, 202 rear drum, 203 hoisting drum, 204 hydraulic cylinder, 210 front leg member, 211 front leg frame, 212 upper frame, 213 Base end portion, 220 rear leg member, 230 lower spreader, 231 lower sheave group, 232 support frame, 233 support shaft, 281 load cell, 300 controller 301, undulation determination unit, 302 correction unit, 303 load calculation unit, 304 winch control unit, 305 display control unit, 306 reference tension setting unit, 307 correction coefficient setting unit, 308 boom operation direction determination unit, 311 input unit, 312 Operation amount sensor, 313 Rotation sensor, 321 Alarm, 322 Stop device, 323 Display unit

Claims (5)

An angle detection device for detecting the boom undulation angle;
A tension detecting device for detecting tension acting on a hoisting rope for hoisting the boom;
A hoisting motion detecting device for detecting hoisting motion of the boom;
A calculation unit for calculating the load of the suspended load;
And a storage device for storing correction coefficient used for correction of the tension acting on the hoist cable,
The correction coefficient is provided according to the boom angle of the boom,
The computing unit is
It acts on the hoisting rope detected by the tension detecting device based on the detection result of the hoisting motion by the hoisting motion detecting device and a correction coefficient corresponding to the hoisting angle of the boom detected by the angle detecting device. A correction unit for correcting the tension;
A load calculation unit that calculates the load of the suspended load based on the tension calculated by multiplying the rope multiplier of the hoisting rope set by the operator by the tension acting on the hoisting rope corrected by the correction unit ; A suspended load calculation device. In the hanging load calculation device according to claim 1,
The computing unit is
When a standing motion is detected by the hoisting motion detection device, a tension acting on the hoisting rope according to the hoisting angle of the boom is detected, and the detected tension is stored in the storage device as a first reference tension. Let
When a tilting motion is detected by the hoisting motion detecting device, a tension acting on the hoisting rope according to the hoisting angle of the boom is detected, and the detected tension is stored in the storage device as a second reference tension. A reference tension setting section to be
Wherein calculating the correction factor based on the first reference tension and the second reference tension, a correction coefficient setting unit to be stored in the storage device, hanging load computing device having a. In the hanging load calculation device according to claim 2,
The correction coefficient setting unit
A suspension load calculation device that calculates the correction coefficient so that the corrected tension becomes an intermediate value between the first reference tension and the second reference tension. In the hanging load calculation device according to claim 3,
The said correction coefficient setting part is a suspension load calculating apparatus which calculates a correction coefficient from following Formula based on the said 1st reference tension and the said 2nd reference tension.

In the hanging load calculating device according to any one of claims 1 to 4,
The correction unit is
When standing motion is detected by the undulation motion detection device, the tension detected by the tension detection device is multiplied by the correction coefficient to obtain a corrected tension,
A suspension load calculation device for multiplying the tension detected by the tension detection device by the reciprocal of the correction coefficient to obtain a corrected tension when a tilting motion is detected by the undulation motion detection device.