JP2007276972A - Overload preventive device of crane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an overload preventive device of a crane capable of changing a rated load characteristic in response to changing work of the winding number of a hook rope to a sheave. <P>SOLUTION: This overload preventive device of the crane has a second hooking number setter 22C setting the second hooking number smaller than the first hooking number of a first hooking number setter 22A, and is characterized by having a control means 20 having a detector 18 detecting the second hooking number of the hook rope, a storage part 20A storing the respective rated load characteristics corresponding to the respective hooking numbers of the first hooking number setter 22A and the second hooking number setter 22C, an arithmetic operation part 20B arithmetically operating a work limit on the basis of the characteristics stored in this storage means 20A, and a change correcting part 20E outputting a command for selecting the rated load characteristic corresponding to the second hooking number setter 22C to the arithmetic operation part 20B on the basis of a signal from the detector 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a crane overload prevention device, and more particularly, to a crane overload prevention device that can cope with a change in the number of hook rope sheaves.

  The crane is equipped with an overload prevention device (moment limiter) for preventing the crane from overturning. The overload prevention device includes a wire multiplier setting switch for setting the number of wires wound, and a limit suspension load changing means for changing the limit of the suspended load according to the number of wires set by the wire multiplier setting switch. (For example, refer to Patent Document 1).

Japanese Patent Application Laid-Open No. 7-165392.

  A crane equipped with this type of overload prevention device is set so that it can be handled at its rated load. Based on this rated load, the number of hook ropes to be wrapped around the sheave is preset to, for example, about 4 hooks.

  In this case, since the number of hook ropes wrapped around the sheave is, for example, four, it is suitable for the load handling of the rated load. Since the speed cannot be increased, the number of hook ropes wrapped around the sheave is changed from, for example, four to two to enable the cargo handling.

  Then, the change in the number of hook rope sheaves is input to the overload prevention device, and for example, a changeover switch for two hooks is used to change the rated load characteristics set in the overload prevention device. Connected.

  However, the operator may be conscious of accelerating the progress of the work, and may forget to turn on the above-described two-hanging changeover switch and start the work. In this case, the overload prevention device must make a safety judgment based on the rated load characteristics corresponding to the double hook. Therefore, depending on the contents of the work, a situation may occur in which a warning instruction is not provided despite an overload.

  The present invention has been made based on the above-described matters, and provides an overload prevention device for a crane that can change its rated load characteristics in response to a change operation of the number of hook rope sheaves. The purpose is to do.

  To achieve the above object, the first invention provides a first multiplier setter for setting a first multiplier of a hook rope to a hook sheave, and a first multiplier setter of the first multiplier setter. A crane overload prevention device comprising a second multiplier setter for setting a second multiplier that is smaller than the multiplier, and a detector that detects an actual multiplier of the hook rope; A storage unit that stores each rated load characteristic corresponding to each multiplier of the first multiplier setter and the second multiplier setter, and an arithmetic unit that calculates a work limit based on the characteristics stored in the storage unit And a control unit having a change correction unit for outputting a command for selecting a rated load characteristic corresponding to a signal from the detector to the calculation unit.

  According to a second aspect of the present invention, in the first aspect, the detector is provided at a corresponding portion of the hook sheave used when the hook rope is set to a second multiplier.

  Furthermore, a third invention is characterized in that, in the first invention, the detector is provided in a corresponding portion of the hook sheave used when the hook rope is set to a first multiplier.

  According to a fourth aspect of the present invention, there is provided a first multiplier setter for setting a first multiplier of the hook rope to the hook sheave and a second multiplier smaller than the first multiplier of the first multiplier setter. A crane overload prevention device comprising a second multiplier setting device for setting a multiplier of the limit switch, provided at a corresponding portion of the hook sheave, for detecting the second multiplier, A storage unit that stores each rated load characteristic corresponding to each multiplier of the first multiplier setter and the second multiplier setter, and an arithmetic unit that calculates a work limit based on the characteristics stored in the storage unit And a control means having a change correction unit that outputs a command for selecting a rated load characteristic corresponding to the second multiplier setter based on a signal from the limit switch to the calculation unit. Features.

  Further, in a fifth invention according to any one of the first to fourth inventions, the change correction unit outputs a command for selecting a rated load characteristic corresponding to a signal from the detector to the arithmetic unit, A lighting signal is output to the lamp of the selected multiplier setting unit.

  According to the present invention, when the number of turns is smaller than the number of turns of the rated load, the rated load characteristics in the overload prevention device can be automatically changed in response to the change work. After changing the multiplier, the cargo handling operation can be started immediately. As a result, the efficiency of the cargo handling work can be improved and the productivity can be increased.

Embodiments of the crane overload prevention device of the present invention will be described below with reference to the drawings.
1 and 2 show an example of a crane provided with an embodiment of the crane overload prevention device of the present invention. FIG. 1 is a side view, and FIG. 2 is a front view in which the upper part of the crane boom is omitted. FIG. In these figures, 1 is a traveling body of a crane, 2 is a revolving body mounted on the upper portion of the traveling body 1 so as to be able to swivel, 3 is a prime mover provided at the rear of the revolving body 2, and 4 is provided on the right front side of the revolving body The driver's cab.

  Reference numeral 5 denotes a multi-stage (in this example, five-stage) telescopic boom provided so as to be movable up and down at the front portion of the revolving structure 2. The multi-stage telescopic boom 5 is moved up and down by a boom hoisting cylinder 6 and the multi-stage telescopic boom 5 It is expanded and contracted by an expansion / contraction cylinder (not shown) provided therein.

  Reference numeral 7 denotes a load-hanging hook. The hook 7 is suspended from the tip of the tip boom 5 </ b> A of the multistage telescopic boom 5. Reference numeral 8 denotes a hook sheave bracket provided on the upper portion of the hook 7, and reference numeral 9 denotes a plurality of hook sheaves provided rotatably on the hook sheave bracket 8. In this example, there are three hook sheaves 9 so that four hook sheaves can be hooked. . Reference numeral 10 denotes a front end bracket of the front end boom 5A in the multistage telescopic boom 5, and 11 denotes a front end sheave that is rotatably arranged in parallel with the bracket 10. In this example, two front end sheaves 11 are provided.

  Reference numeral 12 denotes a hoisting winch, and the hoisting winch 12 is provided on the lower surface of the proximal boom 5B in the multistage telescopic boom 5 as shown in FIG. A hook rope 13 is wound around the hoisting winch 12. One end of the hook rope 13 is wound around the tip sheave 11 and the hook sheave 9, and then fixed to the lower surface of the tip boom 5A. The hook rope 13 is usually hung around the hook sheave 9 by four (first multiplication).

  On the base end boom 5B side of the multistage telescopic boom 5, a boom length detector 14 for detecting the telescopic length of the multistage telescopic boom 5 and a boom angle detector 15 for detecting the elevation angle of the multistage telescopic boom 5 are provided. It has been. In addition, pressure detectors 16 and 17 (not shown, which will be described later) are provided in the piston rod side chamber and the anti-piston rod side chamber of the boom raising / lowering cylinder 6 to detect the internal pressure thereof.

  Further, the hook sheave bracket 8 is provided with a multiplier detector 18 for detecting the number of hook ropes 13 wound as shown in FIG. The mounting structure of the multiplier detector 18 will be described with reference to FIG. In FIG. 3, the same reference numerals as those shown in FIG. 1 denote the same parts. The multiplier detector 18 includes a limit switch 18A. The limit switch 18A is fixed to the hook sheave bracket 8 by a mounting bracket 18C so that the lever 18B faces the intermediate hook sheave 9 of the three hook sheaves 9. Reference numeral 18D denotes a signal line of the limit switch 18A.

The above-described detectors 14 to 18 are connected to an overload detection device 19 described later. The overload detection device 19 is provided in the cab 4. The configuration of the overload detection device 19 will be described with reference to FIG. In FIG. 4, the same reference numerals as those in FIGS. 1 to 3 are the same parts, and detailed description thereof is omitted.
In FIG. 4, the overload detection device 19 calculates information such as a working load by a signal from the pressure detectors 16 and 17 and a working load by a signal from the boom length detector 14 and the boom angle detector 15, Control means 20 for outputting alarm information when these become larger than a preset value, a display unit 21 for displaying numerical values relating to state quantities such as crane posture calculated by the control means 20, and this The display unit 21 and the switch unit 22 for setting provided integrally are configured. The display unit 21 and the setting switch unit 22 provided integrally with the display unit 21 are installed in the cab 4 at a position where it is easy to see and operate.

  The control means 20 described above has a first rated load characteristic set based on the boom length when the hook rope 13 is a first multiplication factor (for example, a multiplication factor of four) and the horizontal working radius of the tip thereof. , And the second rated load characteristic that is set based on the boom length when the hook rope 13 is a second multiplier (for example, two multipliers) and the horizontal working radius of the tip thereof. 20A and the signals from the pressure detectors 16 and 17 calculate information such as the suspension load and the working radius from the signals from the boom length detector 14 and the boom angle detector 15, which are stored in the storage unit 20A in advance. An arithmetic unit 20B that outputs alarm information when it becomes larger than the set value, an input / output unit 20C connected to the display unit 21 side, an input unit 20D connected to the detector side, and a multiplier detector 18 To the signal from And a setting changing unit 20E for selecting the second rated load characteristics stored in the storage unit 20A in Zui.

  The display unit 21 described above includes a crane simulation diagram 21A, a lifting load value display unit 21B provided in correspondence with the simulation diagram 21A, a rated load value display unit 21C, a maximum lift value display unit 21D, and a boom length. A length display unit 21E, a boom angle display unit 21F, a work radius display unit 21G, a load factor display unit 21H, and an overwind warning display lamp 21I are provided. These display units are respectively displayed in response to the calculated value calculated by the control means 20 and the detected value detected by the detector.

  The switch unit 22 described above includes a changeover switch 22 </ b> A that is a setting device for a first multiplier (for example, four multipliers) of the hook rope 13, its operation indicator lamp 22 </ b> B, and a second multiplier of the hook rope 13. In addition to the changeover switch 22C and its operation indicator lamp 22D (for example, the number of multiplications of 2), for example, the inspection switch 22E, the overwind alarm release switch 22F, the traveling suspension changeover switch 22G, the maximum boom angle limit switch 22H, a minimum boom angle limit switch 22I, a maximum working radius limit switch 22J, a maximum lift limit switch 22K, and the like are provided.

  When the first multiplication (for example, 4 multiplication) changeover switch 22A of the hook rope 13 is turned on, the operation display lamp 22B is turned on and is stored in the storage unit 20A of the control means 20 by the insertion signal. When the first rated load characteristic is selected and the second multiplying switch (for example, two multiplying switches) 22C of the hook rope 13 is turned on, the operation display lamp 22D is turned on, and the turning signal is The second rated load characteristic stored in the storage unit 20A of the control means 20 is selected.

  Next, the operation of the above-described crane overload prevention apparatus of the present invention will be described. In order to effectively use the maximum load of the suspended load, the number of windings of the hook rope 13 is used at the maximum number of windings. In this example, it is used with four hooks.

  In this case, the first multiplier (for example, 4 multipliers) changeover switch 22A is turned on to select the first rated load characteristic stored in the storage unit 20A of the control means 20. The input state can be confirmed by lighting of the operation display lamp 22B. By selecting the first rated load characteristic, the control means 20 can provide information such as a working load by signals from the pressure detectors 16 and 17 and suspension loads by signals from the boom length detector 14 and boom angle detector 15. When these are larger than the preset first rated load characteristics, alarm information is output to the display unit 21.

  In the state where the first rated load characteristic is selected, for example, there is a case where it is desired to increase the lift of the hook 7 so as to be suitable for underground work. In this cargo handling operation, the hook rope 13 is used by changing the number of windings of the hook rope 13 from the maximum first number of windings to a second number of windings smaller than this, for example, from four to two. The number of windings is changed by removing one end of the hook rope 13 from the tip boom 5A and hooking it on the middle hook sheave 9 of the three hook sheaves 9.

  At the time of changing the number of windings, the hook sheave 9 pushes the lever 18B of the limit switch 18A serving as a detector toward the hook sheave 9 side. As a result, the limit switch 18A sends the hook rope 13 to one hook sheave 9 of the hook sheave 9, and sends a signal indicating that two hook ropes 13 are hung to the change correction unit 20E of the control means 20. The change correction unit 20E outputs a command for selecting the second rated load characteristic to the calculation unit 20B.

  As a result, the calculation unit 20D calculates information such as the suspension load and the work radius based on the signals from the pressure detectors 16 and 17 and the signals from the boom length detector 14 and the boom angle detector 15, which are stored in advance. When it becomes larger than the set second rated load characteristic, alarm information is output to the display unit 21.

  As a result, the operator can perform the cargo handling operation without turning on the second multiplier changeover switch 22C of the display unit 22, and the workability can be improved. In addition, the safety of subsequent work can be ensured.

  In the above-described embodiment, the change correction unit 20E of the control unit 20 outputs a signal indicating that the hook rope 13 is hung on one hook sheave 9 of the hook sheave 9 and two hook ropes 13 are hung on the arithmetic unit 20B. In response to this, a turn-off signal is output to the operation display lamp 22B of the first multiplier switch 22A, and the operation display lamp 22D of the second multiplier switch 22C is lit. It is also possible to output a signal.

  In the above-described embodiment, the limit switch 18A is provided corresponding to the middle hook sheave 9 of the three hook sheaves 9 as the detector 18 for detecting the change of the second multiplier of the hook rope. As shown in FIG. 5, two limit switches 18A are provided corresponding to the hook sheaves 9 on both sides of the three hook sheaves 9, and the levers 18B of these limit switches 18A are rotated in the direction of arrow A by the hook ropes 13, respectively. It is also possible to configure so that the control means 20 takes in each of the signals that have been moved and turned off, and determines that the signal has been switched to double hooking.

  Furthermore, although the limit switch is used in the above-described embodiment, a non-contact type sensor can also be used. Moreover, in the above-mentioned embodiment, although the multistage telescopic boom was taken as an example, it is applicable also in the case of a single stage boom.

It is a side view showing an example of a crane provided with one embodiment of an overload detection device of the present invention. It is a front view which abbreviate | omits and shows an example of the crane provided with one Embodiment of the overload detection apparatus of this invention shown in FIG. It is a top view which shows an example of the hook rope winding number detector which comprises one Embodiment of the overload detection apparatus of this invention. It is a block diagram of the control means which comprises one Embodiment of the overload detection apparatus of this invention. It is a top view which shows another example of the hook rope winding number detector which comprises one Embodiment of the overload detection apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling body 2 Revolving body 3 Motor | operator 4 Driver's cab 5 Multistage telescopic boom 6 Boom raising cylinder 7 Lifting hook 8 Hook sheave bracket 9 Hook sheave 11 Tip sheave 12 Hoist winch 13 Hook rope 14 Boom length detector 15 Boom Angle detector 16 Pressure detector 17 Pressure detector 18 Multiplier detector 18A Limit switch 19 Overload detection device 20 Control means 20A Storage unit 20B Calculation unit 20E Setting change unit 21 Display unit 22 Switch unit 22A First multiplier setting Change-over switch 22C change-over switch as second multiplier setting device

Claims (5)

  A first multiplier setting unit for setting a first multiplier of the hook rope to the hook sheave, and a second multiplier for setting a second multiplier smaller than the first multiplier of the first multiplier setting unit. A crane overload prevention device comprising a multiplier setting device, a detector for detecting an actual multiplier of the hook rope, the first multiplier setting device and the second multiplier setting device A storage unit storing each rated load characteristic corresponding to each multiplier, a calculation unit calculating a work limit based on the characteristic stored in the storage unit, and a rated load characteristic corresponding to the signal from the detector. A crane overload prevention apparatus comprising: a control unit having a change correction unit that outputs a command to be selected to the calculation unit.   The crane overload prevention device according to claim 1, wherein the detector is provided at a corresponding portion of the hook sheave used when the hook rope is set to a second multiplier.   The crane overload prevention device according to claim 1, wherein the detector is provided in a corresponding portion of the hook sheave used when the hook rope is set to a first multiplier.   A first multiplier setting unit for setting a first multiplier of the hook rope to the hook sheave, and a second multiplier for setting a second multiplier smaller than the first multiplier of the first multiplier setting unit. A crane overload prevention device comprising a multiplier setting device, wherein the limit switch is provided at a corresponding portion of the hook sheave to detect the second multiplier, the first multiplier setting device, A storage unit storing each rated load characteristic corresponding to each multiplier of the second multiplier setter; a calculation unit calculating a work limit based on the characteristic stored in the storage unit; and a signal from the limit switch And a control unit having a change correction unit that outputs a command for selecting a rated load characteristic corresponding to the second multiplier setter based on the calculation unit to the calculation unit. apparatus.   The change correction unit outputs a command for selecting a rated load characteristic corresponding to a signal from the detector to the arithmetic unit, and outputs a lighting signal to a lamp of the selected multiplier setting unit. The overload prevention device for a crane according to any one of claims 1 to 4.

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