JPS5978098A - Method of preventing overload in crane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing overload in cranes equipped with outriggers, such as hydraulic and mechanical trunk cranes and rough terrain cranes.

In the above-mentioned truck cranes and the like, the rated load is generally determined with the outriggers fully extended, and the cranes are to be used in that state. However, in an actual work site, it is not always possible to maintain the OUT+J fully extended state, and there may be cases where work is unavoidably carried out with the actuator partially extended. However, such a state in which the outriggers are partially extended has not been monitored in the past, so overload could not be detected, which could lead to a fall accident. This point will be further explained in detail with reference to FIG.

The rated load of a crane is based on the allowable lifting load limit determined by the hoisting capacity of the crane's hoisting mechanism, the curve of the allowable lifting load determined by the strength of the boom and other groove structures, and the stability against overturning of the crane. The area where the vertical line is drawn is the range in which lifting is possible. When the outriggers are partially extended, the curve (2) based on the above-mentioned overturning transitions to a curve (H), so that the load that can actually be lifted becomes smaller than the rated load within a certain working radius. Therefore, the rated load with the outriggers partially extended is as shown by the curves ■ and ■.
In this case, the diagonal line in Figure 4 @
area is the actual lifting allowable load range. However, in the conventional overload prevention method, it is not possible to detect the partially extended state of the outriggers, and only compares the rated load of the above curve 1, which is determined based on the completely extended state, and the actual load. This made it impossible to detect the load status, leading to the crane falling over.

In addition, as a countermeasure to the above problem, conventionally, the extension length of each outrigger, which was installed two at the front and two at the front, is divided into stages, and the rated load for each state is newly set. However, even in this case, the extended length of each outrigger is always the same and the rated load at each stage is determined, so the individual extended length of each outrigger is not necessarily the same (it cannot be the same). ) It was still insufficient to be suitable for actual work sites.

In view of the above circumstances, the present invention incorporates the individual extension length of each outrigger into the monitoring target, and accurately determines the permissible lifting load from the relative relationship between the extension status of each outrigger and the boom rotation position. This system is designed to perform accurate overload detection and prevent the crane from overturning.

The features of the present invention include detectors for detecting the length of the boom, boom angle, swing angle, and hanging load, and outrigger detectors for detecting the extension length of each outrigger. The information processing device is equipped with an information processing device that receives the detection signal from the detector, and the information processing device has a combination of each element of the boom length, the same luffing angle, and the same turning angle when each outrigger is fully extended. The rated load corresponding to the boom is memorized in advance, and from the relative relationship between the extension status of each outrigger detected by each of the outrigger detectors and the swing angle of the boom, the load rating in the current state determined by the stability against overturning is determined. The above-mentioned information processing device calculates the lifting load, compares this allowable lifting load with the rated load in the state stored in advance in Section 2, and then compares the smaller load of this lifting load with the actually applied load. The present invention relates to a method for preventing overload of a crane, which compares the calculated actual load with the actual load and sends the result to a processing means.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an information processing device such as a microcomputer, and 2 is a processing means for performing overload display and control based on signals sent from the information processing device 1. In FIG.

The information processing device 1 includes a CPU (central processing unit) 8, an RO
M (leat only memory) 4, RAM (random access memory) 5, attenuator times ll! ! ! r6, sample/hold circuit 7, multiplexer 8, A/D converter 9, and Ilo port 10. Also,
The processing means 2 includes a display circuit 11 that displays overload by lighting or blinking a lamp, a driver circuit 12,
It is connected to a relay circuit 13, an alarm circuit 14 that issues an alarm, and an automatic stop circuit 15 that drives the crane's boom elevation electromagnetic pulp, main winding electromagnetic pulp, and auxiliary winding electromagnetic pulp.

On the other hand, the detectors include outrigger detectors 20, 21, 22° 23 for detecting the protruding lengths of the left, front cloth, rear left, and rear right act triggers 16, 17, 18, 19, and the boom 24.
A boom length detector 25 for detecting the length of the boom, a boom hoisting angle detector 26 for detecting the hoisting angle of the boom, a boom swing angle detector 27 for detecting the swing angle of the boom, and a boom hoisting cylinder for detecting the suspended load. A pressure detector 28 and a digital switch 29 for inputting the weight of a lifting device (a hook, a wire for a sling, etc.) operated by an operator are provided at each part of the crane. Note 1. The detection method of each of the above-mentioned detectors can be selected arbitrarily.For example, each outrigger detector 2ON23 and boom length detector 25 measure the length of the wire attached to the tip of the object to be detected by winding the wire. This is converted into the number of rotations of the drum, and this number of rotations is replaced by electric power using a potentiometer. The boom rotation angle detector 27 converts the number of rotations of a gear meshed with the large rotation gear, which corresponds to the rotation angle of the crane 1, into an electric signal 8 using a potentiometer. In addition, the boom hoisting angle detector 26 is
A weight and a potentiometer are connected to detect the angle of the boom 24 relative to the ground (the angle of the boom relative to the horizon),
The boom hoisting cylinder pressure detector 28 detects the cylinder pressure due to the hanging load using a pressure quadrant reducer. or,
Proximity switches or low angle encoders may be used as the outrigger detectors 20 to 23 and the boom rotation angle detector 27.

Next, in Figures 2 and 3, Figure 2 shows the planar position of each part in xy coordinates with the crane rotation center 0 as the origin, the front and back direction of the crane as the X axis, and the left and right direction as the y axis. Figure 3 shows the zoom undulation angle, etc. To explain the symbols shown in both figures, a is the position of the boom foot, and b is the position on the plane of the boom point on the boom center line.1. / is a position on the same side. Further, C is the center of gravity of the upper rotating body 30, d is the planar position of the boom center of gravity, d' is the same side position, e is the position of the center of gravity of the lower traveling body 310, and t is the alignment of the upper rotating body 30, the game 24, and the hanging tool 32. The center of gravity of the entire upper groove relic, g, is the overall center of gravity of the entire crane including the upper structure and the lower traveling body 31. And p is the overturning fulcrum of the crane, θ is the angle due to the poom, α is the same turning angle, L is the zoom length, Ll is the distance from the poom foot to the boom center of gravity d', "1 + h2 + h
3 + 114 are each outrigger 16, 17, 18 .
19 grounding point. i is a straight line connecting the front left and right outrigger grounding points h1, l]2, which is the locus of the tipping fulcrum in the front direction, and j is the grounding point h1. The straight line connecting h3 is the fall trajectory in the left direction, k is the grounding point h3, 114 of the rear left and right act triggers 18.19
m is the trajectory of the tipping fulcrum in the rear direction, and m is the grounding point 112. of the front and rear right actuators 17.19. The straight line connecting h4 is the locus of the tipping fulcrum in the right direction.

On the other hand, in the ROM 4 of the information geographical device 1, the turning angle α is
The boom foot position a when L1, and the xyX coordinate position of the lower traveling center of gravity position e, and the X of each actuator 16 to 19.
Each coordinate position is recorded as a dimension of the crane. The ROM 4 also stores the crane's upper swing weight iWc% boom weight Wds, lower traveling weight layer We, the rated load Ws5 when the outriggers are fully extended, and various calculation formulas to be described later.

Therefore, in order to perform crane work, each outrigger 16
~19 is extended, the length of the extension, that is, each outrigger grounding point '11 t h2 + h 3 + '14
The X coordinate position of each outrigger detector 20.21.22
23, and the detected values are converted to a predetermined level by the attenuation circuit 6, sample/hold circuit 7, multiplexer 8, converter 9, Ilo
It is stored in RAM 5 via port 10. Other detected data (boom length, luffing angle, turning angle, etc.) are also stored in the RAM 5, and this memory content and
Depending on the storage contents of the ROM 4, necessary calculations, quadrant determination and processing are performed.

Now, to the memory contents of ROM4, the outrigger detector 20
From the detection data of ~23, each outrigger grounding point h
The xy coordinates of 1 to h4 are (xf + y
lt), 112 (xf, yrl), h3 (xr + yz2), h4 and 7 (Xr +
Yrz), it is a straight line! +j, m is expressed by the following formula.

Straight line 1 X-z (-(1) Straight line j Straight line 1η
'...(4) When the crane is in the state shown in Figures 2 and 3, the Xy coordinates Xa of the poom foot position Ua
, ya are the xy coordinates at the turning angle α=0 (xaO
, O), then X a −X a 00”α
-+5)ya =x a Q -5inz
...(6) Poom point 1) xy coordinates xl], yb is Xl] = L - c
bsθ −coG(p−tx a
−f7)yl)=Lac
osθ ・sin (n −4−y a
-(8)'' The xy coordinates xc, yc of the center of gravity C of the two-part rotating body 30 are xc=xco-cosff, where the xy coordinates at the turning angle 0-0 are (xcO, O).
,°°(9)yc=xcoOsinα
・(10) xy coordinates xa of the pool center of gravity d
, yd is x d=L 1 ocoS00cos
α+x a −(II)y (1−Ll
s errso 65inQ14-ya
”' (12) On the other hand, the weight Wj of the entire superstructure
W is the hanger type skin input from the digital switch 29.
I) then 'J = Wo (upper rotation weight) - 1 - Wd (weight to Boo @
) + J, ・
...(13) Upper part! xy coordinates xt of center of gravity t of i relic,
yt is the total weight of the entire crane Wg is w g = W t , + W e
...j+6) x of the overall center of gravity g of the entire crane
The y coordinate (xg + yg) is the xy of the lower running center of gravity e
coordinates (xe.

0) Each is represented by .

The overall center of gravity increases as the hanging load increases. Move to the poom point side on the straight line Z connecting the overall center of gravity g when no suspended load is suspended and the zoom point b. In the crane state shown in FIG. 2, the crane will overturn if it crosses the intersection of the straight line Z and the straight line j, that is, the overturning fulcrum p.

Straight line 2 is expressed by the following equation.

When the fall fulcrum is in the first quadrant of the xy coordinate l in Figure 2, 0°≦α〈90゜When it is in the second quadrant, 90°≦θ〈＜180' When it is in the third quadrant, 1800≦ α〈270゜When it is in the fourth quadrant, 270゜≦α〈360゜And, in the case shown, it is determined that the tipping fulcrum p is in the first quadrant, and the straight line 2 has an intersection with the straight line i or the straight line] It is said that To determine whether this overturning fulcrum p is the intersection of the straight line Z and the straight line i or the straight line j, equation (19) is used.
Find X by substituting yll for y.

If it is determined that X in this equation (to) is Therefore, the tipping fulcrum p is defined. In the illustrated state, the intersection with the straight line J is defined as the tipping fulcrum p. Therefore, the xy coordinates (xp, yp) of the tipping fulcrum p can be obtained by solving simultaneous equations of the equation (19) of one straight line and the equation (2) of the straight line j.

Therefore, xf-, xr xb-xg The distance z1 between the tipping fulcrum 1) and the overall center of gravity g is z1=v'
(xp-xg)"+ (yp-yg)" °°
° Distance z2 between tipping fulcrum 1] and zoom point b
isz2- (X'1)-xp)2+(yb Yp)"
°°° (company).

Therefore, the overturning load WR is as follows. According to Japan's safety regulations for cranes, trunk cranes are to be tested for stability with a load 1.27 times the rated load, so the actual allowable lifting load WR required to prevent overturning is The following formula is obtained by multiplying formula (c) by a coefficient.

W R= -OW R 1, 2 □ °°゛(a)" Each calculation 2f+) to (a) is calculated in advance from the RO of the information processing device 1.
M4, and as described above, each outrigger grounding point h1~1]4, zoom length L1, boom lifting angle θ, boom rotation angle change α, lifting tool weight @Wb'! The allowable lifting load WR (curve ■ in Fig. 4), which is determined by the above calculation formula as i-detection data, and the rated load WS at the relevant boom length and zoom luffing angle ( Compare with curve 1) in FIG. And, the permissible lifting load W
In a range where R is the rated electrodynamic W3 and t is also large, the rated load WS is compared with the actual load WU detected by the zoom undulating cylinder pressure detector 28, and it is determined that the allowable lifting load WR is higher than the rated load WS. In a small range, the hanging load is two permissible loads.
R and the actual load WU are compared, and an overload signal is sent from the information processing device 1 to the processing means 2 when the actual load WU approaches the comparison load.

In the processing means 2 to which this overload signal is input, the display circuit 11 lights or flashes a lamp or displays a digital display to indicate the overload to the operator. Further, the driver circuit 12 activates the relay circuit 13 to activate the alarm circuit 14 such as a buzzer, and at the same time or when automatic stop is required, activates the automatic stop circuit 15 to automatically stop the crane operation. .

As mentioned above, according to the present invention, the length of each outrigger is detected, and based on the relative relationship between the extended state of each outrigger and the swinging position of the boom, it is possible to determine whether the suspension is actually suspended at the relevant position. The information processing device calculates the allowable lifting load that can be lifted on the top and the rated load (stored in the information processing device) that is set in advance for the top and bottom of the fully extended state of the AC l-IJ. The smaller of these two types of loads is compared with the actual load that is actually applied, and the comparison results are sent to the processing means.
It is possible to perform reliable overload detection by accurately grasping the outrigger extension situation. For this reason, the work site where the injury occurs,
Even during working conditions, crane overturning accidents can be prevented.

In addition, conventionally, the rated load is set so that the center of gravity when a suspended load is lifted does not exceed the overturning fulcrum on the most disadvantageous side. It becomes a circle as shown by the dotted line. On the other hand, according to the present invention, the rated load can be set according to the boom rotation position, and the locus of the center of gravity position can be made into a rectangular shape connecting adjacent outriggers 16 to 19, so that lifting performance can be maintained at the same temperature. This makes it possible to expand the crane work area.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the general plane and side surface of a crane according to an embodiment of the present invention together with the information processing block, FIG. 2 is a diagram showing the act trigger extension status and others in xy coordinates,
The figure is a schematic side view of the crane, Figure 4 is a diagram for explaining the relationship between rated load and permissible lifting load, and Figure 5 is a diagram for explaining the difference in effect between the method of the present invention and the conventional method. It is. 1... Information processing device, 3... CP that constitutes the device
U, 4... Same ROM, 5... Same RAM, 8...
Multiplexer, 2. Processing means, 11. Display circuit of the same means, 12. Driver circuit, 14.
・Same alarm circuit, 15...Same automatic stop circuit, 16 to 19
...Act trigger, 20-23...Outrigger detector, 24...Boom, 25...Boom length detector, 2
6... The same elevation angle (eating device, 27... The same turning angle detector. Patent applicant Kobe Steel, Ltd. Figure 3 Figure 4 Working radius Figure 5

Claims (1)

[Claims] 1. In a crane equipped with outriggers, each detector detects the length, rotation, old angle, same swing angle, and hanging load of the boom, and the outrigger (ejector and , and an information processing device into which the detection signals from each of these detectors are input, and this information processing device has each element of the boom length, boom angle, and swing angle when each actuator is fully extended. The current state is determined by the stability against overturning based on the relative relationship between the extension status of each outrigger detected by the above-mentioned outrigger detector and the swing angle of the boom. The information processing device calculates the permissible lifting load in each state, compares the permissible lifting load with the pre-stored rated load in the state, and further calculates the smaller of the two loads, A method for preventing overload in a crane, characterized by comparing the actual load actually applied and sending the result to a processing means.