JPS625876B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining a working lift response signal in a crane of the type in which a boom whose base end is pivotally connected to a crane base is driven to raise and lower by a hydraulic cylinder for raising and lowering.

The conventional method for determining the working lift response signal was to calculate the boom length by multiplying it by the sine of the boom hoisting angle. However, in the case of a long boom, the deflection of the boom due to the lifting load and the boom's own weight becomes a value that cannot be ignored, and the working lift response signal is simply obtained by multiplying the sine of the boom's heave angle by the length of the boom. With the conventional method, it is not possible to accurately determine the working lift height. The present invention attempts to obtain a highly accurate working lift response signal by taking into account the deflection of the boom due to the lifting load and the boom's own weight.

The method for obtaining the working lift response signal in the crane of the present invention will be explained in detail below based on the drawings. Fig. 1 shows a truck crane embodying the present invention, the base end of which is pivotally connected to the crane base 1. The boom 2 is driven up and down by a hydraulic cylinder 3 for hoisting, and crane work is carried out by hoisting a load to a hook 4 suspended from the tip of the boom 2 so as to be able to be hoisted up and down. The crane base 1 is adapted to be swingable on a truck 5. l represents the distance between the fulcrum of the boom 2 and the axis of the tip pulley 6 provided at the tip of the boom 2, that is, the boom length, and H represents the boom length.
It represents the vertical distance between the uphill fulcrum and the axis of the end pulley 6 of the boom 2, that is, the working lifting height. h ₁ represents the vertical distance between the fulcrum of the crane base 1 and the ground.
θ represents the heave angle of the straight line S connecting the fulcrum of the boom 2 and the axis of the end pulley 6 of the boom 2 with respect to the horizontal line when the deflection of the boom 2 is set to 0, that is, the heave angle of the boom 2, and Δθ represents the heave angle of the boom 2. 2 is deflected by the lifting load and the dead weight of the boom 2, the angle of the straight line T connecting the fulcrum of the boom 2 and the 6-axis center of the tip pulley of the boom 2 with respect to the straight line S, hereinafter referred to as the deflection angle.

When each code is set as described above, the working lift height H of the boom 2 can be determined by calculating based on the following formula.

H=lsin(θ−Δθ) Here, the length l of the boom 2 is, for example, the length of the boom 2
A length detector 9 continuously detects the length of the cord 8 which is freely wound around the winding drum 7 provided at the base end of the boom 2 and whose tip is fixed to the tip of the boom 2. Therefore, the heave angle θ of the boom 2, which can be easily detected and does not take into account deflection, can be detected, for example, by detecting the angle between the boom 2 and the crane base 1 or the relative angle between the boom 2 and the horizontal line defined by the weight. It can be easily detected by the undulation angle detector 10. In order to obtain a signal responsive to an accurate working lift height H that takes into account the deflection of the boom 2, it is necessary to accurately grasp the deflection angle Δθ and calculate it based on the above calculation formula.

Regarding the deflection angle Δθ, (1) The deflection angle Δθ in the state of the boom 2 in any crane working state (the state of the boom 2 defined by the length of the boom 2 and the luffing angle of the boom 2) is It is approximately proportional to the moment generated around the fulcrum of the boom 2 due to its own weight and the lifting load. Therefore, the boom 2 can be hoisted based on the maximum deflection angle Δθmax when the rated load is lifted in the condition of the boom 2 at that time, the moment Mmax around the boom 2 hoisting fulcrum, the actual load currently being lifted, and the dead weight of the boom 2. Moment M occurring around the fulcrum
If Δθ is known, the deflection angle Δθ can be understood as Δθ≒ΔθmaxM/Mmax.

(2) When the boom 2 is at a certain elevation angle θ,
Rated load (varies depending on boom 2 length l)
The maximum deflection angle Δθmax when the boom is suspended is determined by the proportional distribution formula based on the maximum deflection angle Δθ ₁ max at the length l ₁ of the boom 2 at the relevant heave angle θ and the maximum deflection angle Δθ ₂ max at the boom ₂ length l 2 Δθmax ≒ Δθ ₁ It can be approximately determined from max+Δθ ₂ max−Δθ ₁ max/l ₂ −l ₁ (l−l ₁ ).

In addition, the maximum deflection angle Δθ at each undulation angle
₁ max, Δθ ₂ max may be measured or calculated for each undulation angle, but between the moment and the deflection angle Δθ due to the moment, Δθ=kM (k: constant) Considering the relationship between is proportional to the maximum deflection angle curve drawn with the maximum deflection angle Δθmax on the vertical axis, and therefore,
The maximum moment curve described above may also be used.

Therefore, the maximum deflection angles Δθ ₁ max, Δθ ₂ max at _each heave angle of the boom 2 when lifting the rated load at the boom lengths l 1 and l ₂ ; the actual boom length l of the boom 2; the boom heave angle θ ;Maximum moment generated around the boom 2 hoisting fulcrum when lifting the rated load in each state of the boom 2
If you know the response value of Mmax; the response value of the actual moment M actually generated around the hoisting fulcrum of the boom 2 due to the boom 2's own weight and the lifting load;
The deflection angle Δθ can be approximately determined, and the working lift H can also be determined accurately using this.

Next, one embodiment of the present invention will be described with reference to the drawings.

As already mentioned, 9 is a length detector that continuously detects the length l of the boom 2, and 10 is a heave angle detector that detects the heave angle θ of the boom 2 with respect to the horizontal line. Reference numeral 11 denotes an actual moment output unit that outputs a response value M of the actual moment, that is, the load acting on the hoisting hydraulic cylinder 3 based on the moment generated around the hoisting fulcrum of the boom 2 due to the dead weight of the boom 2 and the lifting load. , consists of a load cell interposed in the piston rod of the hydraulic cylinder 3 for up-and-down. However, this actual moment output section 11 does not necessarily have to be a load cell installed in the piston rod, and may be configured, for example, with a converter that converts the internal pressure of the hydraulic cylinder 3 for luffing into hydraulic power, or a strain meter installed in the boom. The moment acting on the boom may be detected from this strain gauge.

Reference numeral 12 is a maximum moment output unit that outputs a value in response to the maximum moment, which is the response value Mmax of the maximum moment generated around the heave fulcrum of the boom 2 when the rated load in each state of the boom 2 is lifted.
, and receives signals from the undulation angle detector 10 and length detector 9 and outputs a value corresponding to the maximum moment Mmax in the boom state at that time. 13 is a maximum deflection angle output device, which has two different lengths l ₁ of the boom 2;
The maximum deflection angles Δθ ₁ max and Δθ 2 max when lifting the rated load at l ₂ are memorized for each luffing angle, and upon receiving the signal from the luffing angle detector 10, the maximum deflection angle Δθ ₁ max and Δθ 2 max when the rated load is lifted at It outputs the maximum deflection angles Δθ ₁ max and Δθ ₂ max for the two boom lengths. 14 is a relief angle detector 1
0, length detector 9, actual moment output section 11,
_The boom ₂
This is a calculation unit that calculates and outputs a signal responsive to the working lift height H that takes into account the deflection of the head. The calculation of the working lift H in the calculation section 14 is performed in the following manner.

(1) The maximum deflection angle signals Δθ ₁ max and Δθ ₂ max at the current heave angle θ at the lengths l ₁ and l ₂ of the boom 2 from the maximum deflection angle output unit 13 and from the length detector 9 From the length signal l, the maximum deflection angle in the boom 2 state at that time (height angle θ, boom length l) is calculated using the proportional distribution formula Δθ ₁ max + Δθ ₂ max - Δθ ₁ max/l ₂ - _{l 1}
Calculate based on (l-l ₁ ).

(2) Calculate M/Mmax from the actual moment signal response M from the actual moment output section 11 and the maximum moment response signal Mmax from the maximum moment output section 12, and multiply this calculation result and the calculation result in (1) above. Thus, {Δθ ₁ max+Δθ ₂ max−Δθ ₁ max/l ₂ −l ₁ (l−l ₁ )}M/Mmax is obtained. This is the deflection angle Δθ occurring in the boom 2.

(3) Calculate lsin(θ−Δθ) from the deflection angle Δθ obtained from the calculation in (2) above, the heave angle signal θ from the heave angle detector 10, and the length signal l from the length detector 9. A signal is generated in response to the working lift height H taking into account deflection.

In this way, the response signal of the working lift H that takes into account the deflection output from the calculation unit 14 is very close to the actual working lift, and for example, this output can be used to display a display (not shown). It can be activated to inform the crane operator of the exact working lift.

In the above explanation, the deflection angle Δθ and the boom 2
We have explained that the relationship between the response value of the moment acting around the ups and downs fulcrum is proportional, but
The deflection angle can then be determined more accurately than described above. Other embodiments will be described.

(i) The boom length is the standard boom length (this standard boom length means, for example, in a two-stage telescopic boom consisting of two boom tubes as shown in Fig. (This refers to the fully inserted state, and the state where the tip boom is fully extended from the base boom as shown in B). As shown in Figure 4, the horizontal axis represents the response value M of the moment acting around the fulcrum of the boom 2, the vertical axis represents the deflection angle Δθ, and the lifting angle θ of the boom 2 is used as a parameter to calculate the suspended load. For example, if we change the load from zero to the rated load and look at the relationship between M and Δθ, we get the following:
When θ=θ ₁ , it can be shown by a curve like A, and when θ=θ ₂ , it can be shown by a curve like B. (In addition, when drawing this curve, the relationship between M and Δθ may be measured or calculated. In addition, in the figure, M ₁ and M ₂ are when the hanging load is zero, that is, only the boom's own weight (The value is shown when the curve is acting.) When the above curve is expressed by a formula, Δθ=f(M) for each undulation angle. Therefore,
This group of equations showing the relationship between M and Δθ, which change continuously, is stored in the deflection angle output section by providing an arithmetic section in advance, and the signal from the heave angle detector 10 is input to this deflection angle output section. Therefore, by selecting a desired equation of Δθ=f(θ) in the deflection angle output section and inputting the actual moment response signal M from the actual moment output section 11 into this selected equation, the deflection angle Δθ can be determined. can be obtained.

(In the above example, the deflection angle output section has Δθ
The relationship between and M is stored as a continuous function, but as shown by A' and B' in
θ and M may be stored in a discontinuous manner. In this case, for example, for A', the intermediate value Mx between the pre-stored moment response values M ₃ and M ₄ is used as the actual moment. When received from the output section 11, the corresponding deflection angle Δθx is calculated as follows: Δθx=Δθ ₃ +(Δθ ₄ −Δθ ₃ )×Mx−M ₃ /
It can be calculated based on the proportional distribution formula of M ₄ - M ₃ , or by rounding up, M ₄ is calculated as Δ
θ ₄ is rounded down to M ₃ , Δθ ₃ is further rounded off to Δθ ₃ or Δθ ₄ .
The deflection angle output unit may output the deflection angle Δθx corresponding to Mx. ) (ii) Above, we have explained the case where the boom length is the standard boom length, but next, the boom length is the intermediate boom length (this intermediate boom length is, for example, The following describes the case where the boom is in an extended state in which the tip boom is extended and has not yet reached the state shown in FIG. Figures 6 and 7 show the relationship between M and Δθ corresponding to A and B in Figure 3 when the boom length is the reference boom length l ₁₀ and l ₂₀ , respectively, using the heave angle θ as a parameter. Figure 8 shows the relationship between M and Δθ when the boom length is at the intermediate boom length lx _.
Δθx corresponding to M=M ₀ on this prediction diagram is obtained from the following proportional distribution formula.

That is, now, when the heave angle θ=θ ₁ and the corresponding value of the moment is M=M ₀ , the boom length is l ₁₀ ,
If the deflection angles of l ₂₀ are Δθ _A and Δθ _B , the deflection angle Δθx of a boom with luffing angle θ=θ ₁ , M=M ₀ and boom length l=lx is as follows.

Δθx≒Δθ _A +Δθ _B −Δθ _A /l ₂₀ −l ₁₀ (l
x-l ₁₀ ) Next, a method for obtaining a working head response signal in another embodiment will be explained with reference to FIG.

As already mentioned, 9, 10, and 11 are length detectors for detecting the length l of the boom 2, respectively, and boom 2.
an actual moment output unit that outputs the corresponding value M of the moment acting around the fulcrum of the boom 2, and 50 is the reference boom length l ₁₀ , l ₂₀ and The relationship between Δθ and M is memorized for each heave angle, and upon receiving the signal from the actual moment output unit 11, the boom length is determined to be the reference boom length l ₁₀ or
When l ₂₀ , each deflection angle Δθ
is a deflection angle output unit that outputs two deflection angles Δθ corresponding to l ₁₀ and l ₂₀ when the boom length is the intermediate boom length lx. 60 is a length detector 9, an undulation angle detector 10, a deflection angle output section 50,
Receives each signal θ, l, Δθ from boom 2
This is a calculation unit that calculates and outputs a signal responsive to the working lift height H that takes into account the deflection of the head. The calculation of the working lifting height H in the calculation unit 60 can be explained based on the above-mentioned specific example, that is, the boom length is the intermediate boom length lx, the boom heave angle is θ ₁ , and the moment response value is M ₀ as follows. It is done as follows.

Standard boom length l ₁₀ from deflection angle output section 50,
Receiving the deflection angles Δθ _A and Δθ _B at l ₂₀ and receiving the length signal lx from the length detector 9,
The deflection angle is Δθ _A +Δθ _B −Δθ _A /l ₂₀ −l ₁₀ (lx−l
₁₀ ) Calculate based on.

From the deflection angle Δθx obtained in this way and the length signal lx from the length detector 9, lxsin(θ−Δθx) is calculated to generate a signal responsive to the working lift H taking the deflection into account. be.

In addition, the working lifting height H in the above explanation is the boom 2
This refers to the vertical distance from the undulation fulcrum to the axis of the tip pulley, but if the vertical distance from the ground is required, a value corresponding to the distance h ₁ is added to the output value of the calculation units 14 and 60. Needless to say, this is what is required. Furthermore, if you want to find the distance between the bottom end of the hook and the ground surface (ground lift) when the hook is hoisted up to the maximum, a predetermined value can be calculated using the calculation unit 1 described above.
Needless to say, it can be found by subtracting from the output of 4,60 plus _h1 .

In any case, the present invention has the excellent effect of being able to obtain a working lift response signal that is very close to the actual working lifting head in consideration of the deflection of the boom 2.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a crane implementing the present invention;
Figure 2 is a block diagram for explaining the present invention, Figures 3A and 3B are explanatory diagrams of the boom length, and Figures 4 and 5
6, 7, and 8 are explanatory diagrams showing the relationship between the deflection angle and the response value of the moment acting around the boom hoisting fulcrum, and FIG. 9 is a block diagram of another embodiment of the present invention. It is a diagram. 2: Boom, 10: Boom elevation angle detector, 1
1: Actual moment output section, 9: Length detector.

Claims (1)

[Claims] 1 A method for determining the working lifting height response signal for a crane with a boom that can be freely adjusted in elevation, in which the relationship between the boom deflection angle and the load that occurs when a load is applied to the tip of the boom is determined in advance for each boom elevation angle. Store it as a memory value in
During actual crane work, the memorized value of the deflection angle is retrieved based on the luffing angle signal from the luffing angle detector that detects the boom luffing angle during this work, and the signal responsive to the load at this time. This method subtracts the memorized value from the heave angle signal from the boom's heave angle detector, and then multiplies the sine of this subtracted value by the length of the boom to obtain the crane's working lift response signal.