JP7209579B2 - Crane overload prevention method - Google Patents

Description

The present invention relates to a crane overload prevention method.

Generally, a climbing crane is used to construct a structure such as a high-rise building, and has a structure as shown in FIG.

In FIG. 3, reference numeral 1 denotes a climbing crane. The climbing crane 1 is provided with a mast 2 which is installed on a floor plate inside a structure and which serves as a support section capable of successively adding mast blocks 2a upward. A revolving body 4 is rotatably arranged on the top of the mast 2 through an elevating unit 3 which can be vertically moved along the mast 2 . A jib 5 is attached to the revolving body 4 so that it can be raised and lowered, and a counter frame 6 extending rearward is integrally provided. On the counter frame 6, a hoisting drum 9 for hoisting and lowering a hoisting wire rope 8 for suspending a load sling 7 from the tip of the jib 5, and a hoisting wire rope 10 of the jib 5 are hoisted and lowered. A hoisting drum 11 is installed for doing so. The revolving body 4 is provided with a guy support 12. At the top of the guy support 12, a sheave 13 around which the hoisting wire rope 8 unwound from the hoisting drum 9 is wound, and the hoisting drum. A sheave 14 around which the hoisting wire rope 10 let out from 11 is wound is arranged. Further, at the tip of the jib 5, a sheave 15 around which the hoisting wire rope 8 is wound is arranged.

For example, Japanese Patent Laid-Open Publication No. 2002-300000 discloses a general technical level related to the climbing crane 1 as described above.

On the other hand, the climbing crane 1 includes a load detector 20, a jib angle detector 30, an overload prevention device 40, a controller 50, and a display 60, as shown in FIG. 4(a). It is equipped with an overload protection system.

The load detector 20 is composed of a load cell or the like for detecting the tension acting on the hoisting wire rope 8 and measures the actual load of the suspended load acting on the climbing crane 1 .

The jib angle detector 30 measures the inclination angle of the jib 5 .

The overload prevention device 40 has a rated load curve with respect to the working radius of the jib 5 set, obtains the working radius of the jib 5 based on the tilt angle measured by the jib angle detector 30, and determines the working radius of the jib 5 based on the working radius. A rated load is obtained from a rated load curve, and when it is determined that the actual load measured by the load detector 20 exceeds the rated load, a signal to stop the operation of the climbing crane 1 is output.

The controller 50 (PLC: Programmable Logic Controller) makes an emergency stop of the operation of the climbing crane 1 when the operation stop signal output from the overload prevention device 40 is input.

The indicator 60 displays the actual load, the working radius of the jib 5, etc., and also displays an alarm when the operation stop signal output from the overload prevention device 40 is input. .

As shown in FIG. 4(b), the rated load curve set in the overload prevention device 40 is horizontal until the working radius increases to a certain value due to the jib 5 falling from the upright state. The maximum rated load is maintained by displacement, and after the working radius exceeds a certain value, the load rating gradually decreases as the jib 5 falls down and the working radius increases. there is

For example, Patent Document 2 can be cited as a prior art document that discloses the overload prevention device as described above.

JP-A-2004-59321 JP 2017-178502 A

The load detector 20 disclosed in Patent Document 2 for detecting the tension acting on the hoisting wire rope 8 is, for example, in the case of a conventional drum balance crane, a hoisting wire rope as shown in FIG. 8 is connected to a sheave 13b dedicated to load detection which is wound around. Although the load detector 20 such as a tension-type load cell is shown in FIG. 5, a load detector 20 such as a compression-type load cell may be used. In this case, a lever (not shown) having a fulcrum at its intermediate portion is interposed between the load detector 20 such as a compression type load cell and the sheave 13b.

Incidentally, in the example shown in FIG. 5, the hoisting wire rope 8 unwound from the hoisting drum 9 is wound around the sheave 13a at the top of the guy support 12, and then wound around the sheave 13b dedicated to load detection. Furthermore, the sheave 13c at the top of the guy support 12, the sheave 15a at the tip of the jib 5, the sheave 7b for suspending the sheave 7a of the sling 7, the sheave 15b at the tip of the jib 5, and the sheave 13d at the top of the guy support 12 are sequentially hung. , is wound on the luffing drum 11 .

However, the hoisting wire rope 8 unwound from the hoisting drum 9 has two systems, left and right, and the load detector 20 is not provided on the sheave 13b of the right system shown in FIG.

The hoisting wire ropes 10 fed out from the left and right hoisting drums 11 are respectively attached to the sheave 14a at the top of the guy support 12 and to the hoisting pendant sheave block 16 connected to the tip of the jib 5 via the hoisting pendant rope 10a. A sheave 14b attached to the top of the guy support 12, a sheave 14c at the top of the guy support 12, a sheave 14d attached to the pendant sheave block 16, and a sheave 14e attached to the swing sheave block 17 projecting from the top of the guy support 12. , which can be connected.

However, as described above, if the load detector 20 is connected to the load-detecting sheave 13b around which the hoisting wire rope 8 is wound, the number of sheaves increases and the installation of the climbing crane 1 becomes difficult. In some cases, the hoisting wire rope 8 needs to be hung around the sheave 13b dedicated to load detection, and the hoisting wire rope 8 must be lengthened accordingly, so an improvement has been desired.

The present invention has been made in view of the conventional problems described above, and avoids an increase in the number of sheaves. To provide a crane overload prevention method that does not require lengthening.

The present invention comprises a load detection step of measuring a load acting on a sheave around which a hoisting wire rope is wound;
a jib angle detection step of measuring the inclination angle of the jib;
a working radius calculating step for obtaining a working radius of the jib based on the jib inclination angle measured in the jib angle detecting step;
a feed-out angle calculation step of obtaining a feed-out angle of the hoisting wire rope wound around the sheave based on the jib inclination angle measured in the jib angle detection step;
a pull-in angle calculation step of obtaining a pull-in angle of the hoisting wire rope that is wound around the sheave;
The tension of the hoisting wire rope is applied to the crane based on the load measured in the load detection step, the payout angle obtained in the payout angle calculation step, and the retraction angle obtained in the retraction angle calculation step. An actual load calculation process to be obtained as the actual load by the suspended load;
a load rating calculation step of obtaining a rated load from a preset load rating curve based on the working radius obtained in the working radius calculation step;
A comparing step of comparing the actual load obtained in the actual load calculating step with the rated load obtained in the rated load calculating step;
and a stopping step of stopping the operation of the crane when it is determined in the comparing step that the actual load exceeds the rated load.

In the overload prevention method for a crane, when the sheave around which the hoisting wire rope is wound is a sheave disposed on the top of the guy support,
In the delivery angle calculation step, the delivery angle is
θ _W1 = tan ⁻¹ {(H _T −H _G )/(W _G +R)}
=tan ⁻¹ {(L _J sin θ _J +H _F −H _G )/(W _G +R)}
However, H _T : Height from the upper surface of the rotating body to the sheave at the tip of the jib H _G : Height from the upper surface of the rotating body to the sheave at the top of the guy support W _G : From the center of rotation to the sheave at the top of the guy support R: Working radius _LJ : Length of jib _θJ : Inclination angle of jib _HF : Height from the upper surface of the revolving structure to the center of undulation of the jib.

Further, in the pull-in angle calculation step, the pull-in angle is
θ _W2 = tan ⁻¹ {(W _D −W _G )/(H _G −H _D )}
However, W _D : Horizontal length from the turning center to the hoisting drum H _D : Height from the upper surface of the revolving body to the hoisting drum.

Furthermore, in the actual load calculation step, the actual load is
F=P/[2 cos {(θ _W1 +θ _W2 +90°)/2}]
=P/[2 cos {tan ⁻¹ {(L _J sin θ _J +H _F −H _G )/(W _G +R)}
+tan ⁻¹ {(W _D −W _G )/(H _G −H _D )}+90°]/2}]
However, it can be obtained from P: the load to be measured.

According to the crane overload prevention method of the present invention, it is possible to avoid an increase in the number of sheaves. An excellent effect can be obtained that it can be made unnecessary.

1 is a flow chart showing an embodiment of a crane overload prevention method according to the present invention; FIG. 4 is a schematic diagram showing the relationship between the measured value and the tension of the hoisting wire rope in the embodiment of the crane overload prevention method of the present invention. 1 is a schematic configuration diagram showing an example of a general climbing crane; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the conventional overload prevention apparatus, (a) is a control block diagram, (b) is a rated load curve figure. FIG. 11 is a perspective view showing an example of a location where a load detector of a conventional overload prevention device is arranged;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of the crane overload prevention method of the present invention, and in the figures, the same reference numerals as in FIGS. 3 to 5 represent the same parts.

In the case of this embodiment, as shown in FIG. 1, there are a load detection process, a jib angle detection process, a working radius calculation process, a feed angle calculation process, a retraction angle calculation process, an actual load calculation process, and a rated load calculation. It includes a step, a comparing step, and a stopping step.

The load detection step is a step of measuring the load P acting on the sheave around which the hoisting wire rope 8 is wound. Here, the sheave around which the hoisting wire rope 8 is wound can be a sheave 13 arranged on the top of the guy support 12, and a load detector 20 such as a load cell is incorporated in the shaft of the sheave 13. It's like However, the sheave in which the load detector 20 is incorporated in the shaft may be a sheave other than the sheave 13 arranged on the top of the guy support 12 (for example, sheave 13d or sheave 15 shown in FIG. 5). Moreover, the load detector 20 can be incorporated not only in the shaft of the sheave, but also in the axis of the undulation center of the jib 5 or a connecting pin provided in the intermediate portion of the jib 5, for example.

The jib angle detection step is a step of measuring the inclination angle _θJ of the jib 5 .

The working radius calculating step is a step of obtaining the working radius R of the jib 5 based on the inclination angle _θJ of the jib 5 measured in the jib angle detecting step.

The payout angle calculation step is a step of obtaining the payout angle _θW1 of the hoisting wire rope 8 wound around the sheave 13 based on the inclination angle _θJ of the jib 5 measured in the jib angle detection step.

The pull-in angle calculation step is a step of obtaining the pull-in angle θ _W2 of the hoisting wire rope 8 wound around the sheave 13 .

The actual load calculation step is based on the load P measured in the load detection step, the extension angle _θW1 obtained in the extension angle calculation step, and the retraction angle _θW2 obtained in the retraction angle calculation step. , the tension of the hoisting wire rope 8 is obtained as the actual load F by the suspended load acting on the climbing crane 1 .

The rated load calculating step is a step of obtaining a rated load from a preset load rating curve based on the working radius R obtained in the working radius calculating step.

The comparing step is a step of comparing the actual load F obtained in the actual load calculating step with the rated load obtained in the rated load calculating step.

The stopping step is a step of stopping the operation of the climbing crane 1 when it is determined in the comparing step that the actual load F exceeds the rated load.

Next, the operation of the above embodiment will be described.

When a load is lifted by the climbing crane 1, the load P acting on the sheave 13 around which the hoisting wire rope 8 is wound is first measured as a load calculation step (see step S10 in FIG. 1).

At the same time, the inclination angle _θJ of the jib 5 is measured as a jib angle detection step (see step S20 in FIG. 1).

Subsequently, as a working radius calculation step, a working radius R of the jib 5 is obtained based on the inclination angle θ _J of the jib 5 measured in the jib angle detection step (see step S30 in FIG. 1).

Further, in the payout angle calculation step, the payout angle _θW1 of the hoisting wire rope 8 wound around the sheave 13 is obtained based on the inclination angle _θJ of the jib 5 measured in the jib angle detection step (Fig. 1). (see step S40).

Simultaneously with the payout angle calculation step, a pull-in angle _θW2 of the hoisting wire rope 8 wound around the sheave 13 is obtained as a pull-in angle calculation step (see step S50 in FIG. 1).

Thereafter, the actual load is calculated based on the load P measured in the load detection step, the extension angle _θW1 obtained in the extension angle calculation step, and the retraction angle _θW2 obtained in the retraction angle calculation step. process is performed. In the actual load calculation process, the tension of the hoisting wire rope 8 is obtained as the actual load F by the suspended load acting on the climbing crane 1 (see step S60 in FIG. 1).

Further, as a load rating calculation step, a load rating is obtained from a preset load rating curve based on the working radius R obtained in the working radius calculation step (see step S70 in FIG. 1).

Then, the actual load F obtained in the actual load calculation step is compared with the rated load obtained in the rated load calculation step (see step S80 in FIG. 1).

When it is determined in the comparison step that the actual load F exceeds the rated load, the operation of the climbing crane 1 is stopped as a stopping step (see step S90 in FIG. 1).

If it is determined in the comparison step that the actual load F does not exceed the rated load, the climbing crane 1 continues to operate, returns to the load detection step and the jib angle detection step, and performs the same steps as described above. Repeatedly.

A method of calculating the extension angle θ _W1 , the retraction angle θ _W2 , and the actual load F (tension F) will be described in detail below with reference to FIG.

In the example shown in FIG. 2, the sheave 13 around which the hoisting wire rope 8 is wound is disposed on the top of the guy support 12, and a load detector 20 such as a load cell is incorporated in the shaft of the sheave 13. The measured value of the load due to is P.

The height _HT from the upper surface of the revolving body 4 to the sheave 15 at the tip of the jib 5 is defined by the length of the jib 5 being _LJ and the height from the upper surface of the revolving body 4 to the center of undulation of the _jib 5 being HF. In this case, since the inclination angle _θJ of the jib 5 is measured in the jib angle detection process,
H _T =L _J sin θ _J +H _F
is required as Incidentally, in FIG. 2, _WF is the horizontal length from the turning center to the hoisting center of the jib 5 .

Also, if the horizontal length from the turning center to the sheave 13 at the top of the guy support 12 is _WG , and the height from the upper surface of the rotating body 4 to the sheave 13 at the top of the guy support 12 is _HG , the working radius is: Since R is obtained based on the inclination angle _θJ of the jib 5,
(W _G +R) tan θ _W1 =H _T -H _G
A relationship is established.

That is, in the delivery angle calculation step, the delivery angle is
θ _W1 = tan ⁻¹ {(H _T −H _G )/(W _G +R)}
=tan ⁻¹ {(L _J sin θ _J +H _F −H _G )/(W _G +R)}
more sought after.

Furthermore, when the height from the upper surface of the revolving body 4 to the hoisting drum 9 is _{H D} and the horizontal length from the revolving center to the hoisting drum 9 is WD,
(H _G −H _D ) tan θ _W2 =W _D −W _G
A relationship is established.

That is, in the pull-in angle calculation step, the pull-in angle is
θ _W2 = tan ⁻¹ {(W _D −W _G )/(H _G −H _D )}
more sought after.

The load P to be measured is the tension F acting on the hoisting wire rope 8 unwound from the sheave 13 to the tip side of the jib 5, and the hoisting wire rope 8 drawn from the sheave 13 to the hoisting drum 9 side. It is a resultant force with the acting tension F, and if the resolution angle of the load P with respect to the tension F is φ, from the vector synthesis relational expression,
F=P/2cosφ
φ=( _θW1 + _θW2 +90°)/2
A relationship is established.

That is, since the tension F becomes the actual load, in the actual load calculation step, the actual load is
F=P/[2 cos {(θ _W1 +θ _W2 +90°)/2}]
=P/[2 cos {tan ⁻¹ {(L _J sin θ _J +H _F −H _G )/(W _G +R)}
+tan ⁻¹ {(W _D −W _G )/(H _G −H _D )}+90°]/2}]
more sought after.

In the present embodiment, unlike the conventional case, the load detector 20 does not need to be connected to the load-detecting sheave 13b (see FIG. 5) around which the hoisting wire rope 8 is wound. In addition, when the climbing crane 1 is installed, it is possible to omit the work of winding the hoisting wire rope 8 around the sheave 13b dedicated to load detection, and the hoisting wire rope 8 does not have to be long. done.

In this way, an increase in the number of sheaves can be avoided, and it is possible to eliminate the need for extra work to wind the sheave 13b dedicated to load detection of the hoisting wire rope 8 and lengthening the hoisting wire rope 8 when the climbing crane 1 is installed.

In this embodiment, when the sheave around which the hoisting wire rope 8 is wound is the sheave 13 disposed on the top of the guy support 12,
In the delivery angle calculation step, the delivery angle is
θ _W1 = tan ⁻¹ {(H _T −H _G )/(W _G +R)}
=tan ⁻¹ {(L _J sin θ _J +H _F −H _G )/(W _G +R)}
However, H _T : Height from the upper surface of the rotating body 4 to the sheave 15 at the tip of the jib 5 H _G : Height from the upper surface of the rotating body 4 to the sheave 13 at the top of the guy support 12 W _G : From the center of rotation to the sheave 13 Horizontal length from the top of the support 12 to the sheave 13 _R : Working radius LJ: Length of the jib 5 _θJ : Inclination angle of the jib 5 _HF : Height from the upper surface of the revolving structure 4 to the center of undulation of the jib 5 more sought after.

Further, in the pull-in angle calculation step, the pull-in angle is
θ _W2 = tan ⁻¹ {(W _D −W _G )/(H _G −H _D )}
However, W _D : horizontal length from the turning center to the hoisting drum 9 H _D : height from the upper surface of the revolving body 4 to the hoisting drum 9

Furthermore, in the actual load calculation step, the actual load is
F=P/[2 cos {(θ _W1 +θ _W2 +90°)/2}]
=P/[2 cos {tan ⁻¹ {(L _J sin θ _J +H _F −H _G )/(W _G +R)}
+tan ⁻¹ {(W _D −W _G )/(H _G −H _D )}+90°]/2}]
However, P is the load to be measured.

This is effective in eliminating the need for the sheave 13b dedicated to detecting the load of the hoisting wire rope 8.

It should be noted that the overload prevention method for a crane according to the present invention is not limited to the above-described embodiment, and can be applied to any crane having a jib, not limited to a climbing crane. In addition, it goes without saying that various modifications can be made without departing from the gist of the present invention.

1 climbing crane (crane)
2 Mast 2a Mast Block 3 Lifting Unit 4 Revolving Body 5 Jib 6 Counter Frame 7 Hoist 7a Sheave 7b Sheave 8 Hoisting Wire Rope 9 Hoisting Drum 10 Luffing Wire Rope 10a Luffing Pendant Rope 11 Luffing Drum 12 Guy Support 13 Sheave 13a Sheave 13b sheave 13c sheave 13d sheave 14 sheave 14a sheave 14b sheave 14c sheave 14d sheave 14e sheave 15 sheave 15a sheave 15b sheave 16 luffing pendant sheave block 17 luffing swing sheave block 20 load detector 30 jib angle detector 40 overload protector 50 control Device 60 Display P Load F Actual load (tension)
R Working radius θ _J Inclination angle θ _W1 Extension angle θ _W2 Retraction angle HT Height from upper surface of rotating body to sheave at tip of _{jib HG} Height from upper surface of rotating body to sheave at top of guy support W _G Horizontal length from turning center to sheave at top of guy support L _J Jib length _HF Height from top surface of rotating body to jib undulation center WD Horizontal length from turning center to hoisting drum _{H D} Height from the upper surface of the rotating body to the hoist drum _WF Horizontal length from the center of rotation to the center of jib undulation

Claims (4)

a load detection step of measuring the load acting on the sheave around which the hoisting wire rope is wound;
a jib angle detection step of measuring the inclination angle of the jib;
a working radius calculating step for obtaining a working radius of the jib based on the jib inclination angle measured in the jib angle detecting step;
a feed-out angle calculation step of obtaining a feed-out angle of the hoisting wire rope wound around the sheave based on the jib inclination angle measured in the jib angle detection step;
a pull-in angle calculation step of obtaining a pull-in angle of the hoisting wire rope that is wound around the sheave;
The tension of the hoisting wire rope is applied to the crane based on the load measured in the load detection step, the payout angle obtained in the payout angle calculation step, and the retraction angle obtained in the retraction angle calculation step. An actual load calculation process to be obtained as the actual load by the suspended load;
a load rating calculation step of obtaining a rated load from a preset load rating curve based on the working radius obtained in the working radius calculation step;
A comparing step of comparing the actual load obtained in the actual load calculating step with the rated load obtained in the rated load calculating step;
and a stopping step of stopping the operation of the crane when it is determined in the comparing step that the actual load exceeds the rated load. When the sheave around which the hoisting wire rope is wound is a sheave arranged at the top of the guy support,
In the delivery angle calculation step, the delivery angle is
θ _W1 = tan ⁻¹ {(H _T −H _G )/(W _G +R)}
=tan ⁻¹ {(L _J sin θ _J +H _F −H _G )/(W _G +R)}
However, H _T : Height from the upper surface of the rotating body to the sheave at the tip of the jib H _G : Height from the upper surface of the rotating body to the sheave at the top of the guy support W _G : From the center of rotation to the sheave at the top of the guy support R: working radius _LJ : jib length _θJ : jib inclination angle _HF : height from the upper surface of the revolving structure to the jib undulation center Prevention method. In the pull-in angle calculation step, the pull-in angle is
θ _W2 = tan ⁻¹ {(W _D −W _G )/(H _G −H _D )}
However, W _D : horizontal length from turning center to hoisting drum H _D : height from upper surface of revolving body to hoisting drum The method for preventing overload of a crane according to claim 2 . In the actual load calculation step, the actual load is
F=P/[2 cos {(θ _W1 +θ _W2 +90°)/2}]
=P/[2 cos {tan ⁻¹ {(L _J sin θ _J +H _F −H _G )/(W _G +R)}
+tan ⁻¹ {(W _D −W _G )/(H _G −H _D )}+90°]/2}]
However, the method for preventing overload of a crane according to claim 3, wherein P is the load to be measured.

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