JP2010228900A - Load calculating device for crane and crane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load calculating device for a crane capable of accurately calculating a load. <P>SOLUTION: The load calculating device 5 for the crane includes a wire 40 for hanging a hook 79, and sheaves 71-78 for winding the wire 40. The load calculating device 5 further includes a load detector 53 for detecting the load acting on the wire 40, and a load correcting means 51 for correcting the detected load to a load with frictional force of the sheaves 71-78 removed, based on the rotational direction of the sheaves 71-78. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a crane load calculation device and a crane.

  Conventionally, cranes have been equipped with safety devices to prevent overturning, etc., and it is known to determine whether or not the state is dangerous based on the detected load of the suspended load or the posture of the boom and warn the operator. Yes.

  For example, Patent Document 1 discloses a crane monitoring device that includes a position detection unit, a load detection unit, and a calculation unit, and notifies the operator of numerical information output from the calculation unit by a voice conversion unit. Yes.

  According to this configuration, since the numerical information is converted into voice and notified to the operator, the burden of visually confirming various numerical information can be reduced, and an accident can be prevented from occurring due to oversight of the numerical information.

JP-A-7-309584

  However, in the conventional techniques such as Patent Document 1 described above, since the frictional force accompanying the rotation of the sheave acts when detecting the load, the load cannot be detected accurately.

  That is, when the suspended load 80 (weight W) is to be lifted, as shown in FIG. 8A, the frictional force f acts in the direction opposite to the rotation direction (left) and the right direction (right) of the sheave 70. A load of (W + f) acts on the hand H (corresponding to the load detection means).

  On the other hand, when the suspended load 80 is to be suspended, as shown in FIG. 8B, as a result of the frictional force f acting in the direction opposite to the rotation direction (right) of the sheave 70 (left), the hand H A load of (W−f) acts on.

  Thus, since the load value measured by changing the acting direction of the frictional force f varies depending on the rotation direction of the sheave 70, the load cannot be accurately detected.

  Therefore, an object of the present invention is to provide a crane load calculation device that can accurately calculate a load, and a crane including the crane load calculation device.

  In order to achieve the above object, a crane load calculation device according to the present invention is a crane load calculation device including a wire for hanging a hook and a sheave for hanging the wire, and detects a load acting on the wire. A detector; and load correction means for correcting the detected load based on the rotation direction of the sheave.

  As described above, the crane load calculation device according to the present invention is a crane load calculation device including a wire and a sheave, a load detector that detects a load acting on the wire, and a rotation of the sheave by detecting the detected load. Since load correcting means for correcting based on the direction is provided, the accuracy of load detection of the suspended load is improved. Therefore, the accuracy of the stop control based on the detected load is improved, and it is possible to work safely.

It is a block diagram explaining the structure of the control system of the load calculating apparatus of the crane of Example 1. FIG. It is a side view explaining the structure of a crane. It is explanatory drawing explaining the structure of a load detector. (A) is a front view, (b) is explanatory drawing explaining balance of force. It is explanatory drawing explaining the relationship of a load. It is explanatory drawing explaining the relationship between raising of a jib and wire length. It is a time chart of the load detected with a load detector. It is explanatory drawing explaining the positional relationship of a sheave and a load detector. (A) is a case where a load detector is provided on the jib tip side, and (b) is a case where a load detector is provided on the hook side. It is explanatory drawing explaining the relationship between the rotation direction of a sheave, and the action direction of frictional force. (A) is a case of winding, and (b) is a case of lowering.

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

  First, the whole structure of the all terrain crane 1 as a crane provided with the load calculating apparatus 5 of the crane of this invention is demonstrated using FIG. In the present embodiment, the all terrain crane 1 is described as an example of the crane, but the present invention can be applied to any crane as long as it has a wire and a sheave.

  As shown in FIG. 2, the all terrain crane 1 of the present embodiment includes a vehicle body 10 having a traveling function, a swivel base 11 that can be horizontally swiveled on the car body 10, and a boom that can be undulated on the swivel base 11. 2 and a jib 3 attached to the tip of the boom 2 so as to be raised and lowered.

  The boom 2 is formed to be telescopic by stacking steel cylinders in a nested manner, and a base portion is attached to a rotating shaft of the swivel base 11 to raise and lower the hoisting cylinder 21. To surrender.

  The jib 3 is used to increase the working radius and the working head, and to carry out nostalgic work. The jib 3 is formed as a lattice jib in which steel materials are assembled in a truss shape. Mounted on the shaft in a undulating manner.

  Further, masts 61 and 62 are erected on the back side of the jib 3, and links 63, 62 are respectively provided between the front end mast 61 and the jib 3 and between the front end mast 61 and the rear end mast 62. 64 is built.

  A holding wire 41 for holding the jib 3, the masts 61 and 62, the links 63 and 64, etc. is hung on the back side of the integrated jib 3. One end of the holding wire 41 is attached to the jib 3, and the other end is wound around a holding winch 67 disposed on the swivel base 11.

  And the sheaves 74-76 are attached to the tip of the jib 3, and the lifting wire 40 is hung so as to reciprocate between the sheaves 71-73 of the hook block 79 (FIG. 7A). reference). In addition, sheaves 77 and 78 are also attached to the masts 61 and 62, respectively, to guide the lifting wire 40 to the lifting winch 66.

  These sheaves 71 to 78 are pulleys provided for smoothly winding and unwinding the lifting wire 40 by the lifting winch 66. A bearing is disposed between the rotating shaft and the friction resistance. Has been reduced.

  However, even when the bearing is arranged, a frictional force is generated between the bearing and the rotating shaft. Therefore, when all the sheaves 71 to 78 are combined, the frictional force may reach 7 to 8% of the weight of the suspended load 80.

  A load cell 53 as a load detector is attached to the sheave 77 of the mast 61 on the distal end side of this embodiment so as to hold the rotating shaft of the sheave 77 and pull it outward (FIG. 3 (a). )reference). The load cell 53 always measures the load while lifting the suspended load 80 and immediately notifies the load correcting means 51 (see FIG. 1).

  As shown in FIG. 3B, the load cell 53 as the load detector has an outward reaction force Fl so as to face the resultant force of the two directions of tensions Ft and Fm acting on the sheave 77 from the lifting wire 40. Is generated. And it converts into a load by measuring the resistance change by the produced distortion.

  Therefore, as shown in FIG. 4, the weight W of the suspended load 80 can be calculated by measuring the outward reaction force Fl acting on the sheave 77.

  That is, the case of winding will be described as an example. The friction force (f1 +... + F6) by the sheaves 71 to 76 and 1/6 of the weight W of the suspended load act on the tip side of the sheave 77 to which the load cell 53 is attached. However, 1/6 of the frictional force (f1 +... + F7) by the sheaves 71 to 77 and the weight W of the suspended load 80 acts on the rear end side.

  In addition, since the angle formed by the sheave 76, the sheave 77, and the sheave 78 is always constant, calculating the component in the direction of the load cell 53 of the tension in the two directions described above will balance the reaction force by the load cell 53.

  Then, the weight W of the suspended load 80 can be calculated by measuring these frictional forces f1,..., F7 in advance at the time of shipment.

  Next, the configuration of the control system of the all terrain crane 1 of the present embodiment will be described.

  As shown in FIG. 1, the all-terrain crane 1 of the present embodiment includes the load cell 53 described above as posture detection means for detecting the posture of the boom 2 and jib 3 and load detection means for detecting the load of the suspended load 80 described above. In addition, a safety device 50 that receives the posture information from the posture detection means and the load detection means and monitors the total center of gravity position, the overturning moment, and the like is disposed.

  As the posture detection means, a dibutylt angle detector 54, a boom undulation angle detector 55, a boom length detector 56, a winch rotation detector 57, and the like are arranged.

  The safety device 50 is disposed inside the swivel base 11 and is constituted by a general-purpose microcomputer having a central processing unit (CPU), ROM, RAM, flash ROM, EEPROM (registered trademark), and the like.

  In the safety device 50, a moment calculating means 52 for preventing the all-terrain crane 1 from falling over and operating it safely, a load correcting means 51 for accurately calculating a load, and the like are executed. The load cell 53 as a load detector and the load correction means 51 constitute a crane load calculation device 5.

  The moment calculator 52 corrects the accurate value by the load corrector 51 and accurately calculates the overturning moment based on the load value substantially equal to the actual weight W, the posture of the boom 2 and the jib 3, and the like.

  Moreover, the load correction means 51 corrects the measurement value detected by the load cell 53 as a load detector by the rotation direction of the sheaves 71 to 78 and the friction force set in advance. The correction value based on the frictional force may be set for each wire multiplier.

  Of these, the rotational direction includes the geometric change amount of the length of the lifting wire 40 due to the posture change of either the boom 2 or the jib 3 as shown in FIG. 5 and the winch drum detected by the winch rotation detector 57. It is determined by comparing the magnitude of the rotational change in the length of the lifting wire 40 due to the rotation.

  That is, when the jib 3 is lifted with the lifting winch 66 stopped, the distance from the lifting winch 66 to the tip of the jib 3 is shortened by the geometric change amount as shown in FIG. As the suspended load 80 moves downward, the sheaves 71 to 78 rotate in the direction of unwinding the load.

  On the other hand, if the lifting winch 66 is wound up by the same amount as the geometric change amount simultaneously with the raising of the jib 3, the suspended load 80 becomes stationary and the sheaves 71 to 78 do not rotate.

  Further, if the lifting winch 66 is wound up to the geometric change amount or more simultaneously with the raising of the jib 3, the suspended load 80 moves upward, so that the sheaves 71 to 78 rotate in the direction of winding up the load.

  Next, the operation and effect of the all terrain crane 1 of the present embodiment will be described.

  (1) As described above, the crane load calculation device 5 according to the present embodiment includes the lifting wire 40 as a wire for hanging the hook block 79 and the sheaves 71 to 78 for hanging the lifting wire 40. 5.

  And the load cell 53 as a load detector which detects the load which acts on the lifting wire 40, and the load detected by the load cell 53 was removed based on the rotational direction of the sheaves 71-78. Load correction means 51 for correcting to an accurate load.

  As described above, if the influence of the frictional force of the sheaves 71 to 78 can be excluded from the load value (measured value) measured by the load cell 53, the accuracy of detecting the weight W of the suspended load 80 is improved. To do. Therefore, the accuracy of the stop control based on the detected load is improved, and it is possible to work safely.

  That is, since the frictional force of the sheaves 71 to 78 acts at a predetermined size regardless of the position of the suspended load 80, the sheaves 71 to 78 rotate in the direction of lowering the load with a large working radius. In such a case, there is a possibility that a dangerous state is detected because the load is detected smaller than the actual load.

  On the other hand, when the sheaves 71 to 78 rotate in the direction to lift the load, the load is detected in a safe state because the load is detected larger than the actual load, but the rated load displayed as the performance cannot be actually lifted. There was a problem that cases could arise.

  Therefore, by correcting the measurement value according to the frictional force and the rotation direction and calculating an accurate load, it is possible to avoid a dangerous state when the sheaves 71 to 78 are rotated in the lowering direction, and also the sheaves 71 to 78. It is possible to prevent the rated load from being lifted when rotating in the direction of winding.

  Further, even when the load cell 53 is installed near the suspended load 80, the frictional force always acts (although it changes depending on the number of sheaves), so that an accurate load cannot be calculated. Is big.

  In order to reduce the influence of the frictional force, the load cell 53 can be attached at a position as shown in FIGS. As shown in FIG. 7 (a), if the boom 2 is attached to the front end of the rope end stop, the sheaves 71 to 76 at the front end must always be an even number, and there is a problem that the speed is also slowed down. Further, when it is attached to the hook block 79 side as shown in FIG. 7B, there is a problem that it is necessary to adjust the length of the communication line as the hook block 79 moves.

  (2) Further, the load correction means 51 includes a geometric change amount of the length of the lifting wire 40 based on a change in posture of at least one of the jib 3 and the boom 2, and rotation of the winch drum around which the lifting wire 40 is wound. The rotational direction of the sheaves 71 to 78 is determined by comparing the rotational change amount of the length of the lifting wire 40 due to the above.

  For this reason, even if it does not attach the rotation direction detector only for detecting a rotation direction to either sheave 71-78, a rotation direction can be detected by the existing attitude | position detection means.

  (3) Furthermore, if a rotation direction detector is attached to any one of the sheaves 71 to 78, the load correcting means 51 can detect the rotation direction of the sheaves 71 to 78 by this rotation direction detector.

  Thus, by directly detecting the rotational direction of the sheaves 71 to 78, the direction of the frictional force can be grasped more accurately.

  (4) Further, the load correction means 51 determines the friction of the sheaves 71 to 78 based on the average value of the loads detected while the load cells 53 are reversing the loads detected by the load cell 53 while the sheaves 71 to 78 are rotating forward. It is preferable to further correct the load excluding the force.

  Specifically, for example, the provisional true load value is obtained by subtracting the friction force set in advance from the load value measured at the time of ground cutting. It is possible to correct more accurately by calculating an average value and the like.

  The true value can be updated by replacing it with a value set in advance in a test or the like. Thereby, even if the friction state of the rotating shaft of the sheaves 71 to 78 changes with time, an accurate value can always be set.

  As an example, FIG. 6 shows the relationship between the operation of the boom 2 and the jib 3 and the corresponding tension (load).

  Each operation will be described in order. (A) A hook block 79 is hung on the suspended load 80 and the lifting wire 40 is wound up. (B) The suspended load 80 moves away from the ground (ground cutting). (C) Stop winding. (D) An operation (raising) for reducing the tilt angle of the jib 3 is performed. (E) The tension of the lifting wire 40 decreases. (F) The tilt operation of the jib 3 is stopped. (G) Start turning. (H) Stop turning at the same time. (I) The suspended load 80 starts to reach the ground. (J) The suspended load 80 is completely landed.

  As shown in FIG. 6, when the jib 3 is lifted so as to reduce the tilt angle in (d) to (e), the rotational direction of the sheaves 71 to 78 is changed, and the direction of action of the friction force is reversed. The load (tension) changes.

  And it is estimated that the measured value is (W + f) on the upper side of (b) to (d), and the measured value is (W−f) on the lower side of (e) to (i). Therefore, it is considered that the average value (median value) of both corresponds to the true weight W of the suspended load 80.

  When the true weight W is calculated in this way, the actually measured value is used instead of the value set in advance as the frictional force f, so that the weight W can be calculated more accurately.

  (5) And the all terrain crane 1 as a crane of a present Example becomes the all terrain crane 1 which can prevent the fall of the load detection precision by operation | movement of a crane by providing the load calculating device 5 of one of the above-mentioned cranes. .

  The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention are not limited to the present invention. included.

  For example, in the above-described embodiment, the case where the load cell 53 is attached to the mast 61 and the load is measured has been described. The present invention can also be applied.

  In the above-described embodiment, the load cell 53 constantly measures the load while lifting the suspended load 80 and notifies the load correcting means 51 of the load. However, the present invention is not limited to this. The load due to may be measured only when the ground is cut. For example, the lifting winch 66 is always in the winding direction when the ground is cut, and the sheaves 71 to 78 are also rotated in the winding direction, so that an accurate load can be calculated by subtracting the frictional force from the load detected when the ground is cut. .

DESCRIPTION OF SYMBOLS 1 All terrain crane 2 Boom 3 Jib 40 Lifting wire 5 Crane load calculating device 50 Safety device 51 Load correcting means 52 Moment calculating means 53 Load cell (load detector)
54 Dibutylt angle detector 55 Boom hoisting angle detector 56 Boom length detector 57 Winch rotation detector 61, 62 Mast 66 Lifting winch 71-78 Sheave 79 Hook block 80 Suspended load

Claims (5)

A crane load calculation device comprising a wire for hanging a hook and a sheave for hanging the wire,
A crane load calculation device comprising: a load detector that detects a load acting on the wire; and a load correction unit that corrects the detected load based on a rotation direction of the sheave.   The load correction means compares the geometric change amount of the wire length based on the posture change of at least one of the jib or the boom and the rotation change amount of the wire length due to the rotation of the winch drum around which the wire is wound. The crane load calculation device according to claim 1, wherein the rotation direction of the sheave is determined.   2. The crane load calculation device according to claim 1, wherein a rotation direction detector is attached to the sheave, and the load correction means detects the rotation direction of the sheave by the rotation direction detector.   The load correction means further corrects the corrected load by an average value of a load detected while the sheave is rotating forward and a load detected while the sheave is rotating forward. The crane load calculation device according to any one of claims 1 to 3.   The crane provided with the load calculating apparatus of the crane as described in any one of Claims 1 thru | or 4.

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