JPS6225596B2 - - 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 performance by multiplying the length of the boom 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.

A method for obtaining a working lift response signal in a crane according to the present invention will be explained in detail below based on the drawings.

Fig. 1 shows a truck crane in which the present invention is implemented, in which a boom 2 whose base end is pivotally connected to a crane base 1 is driven to be hoisted by a hoisting hydraulic cylinder 3, and from the tip of the boom 2 Crane work is carried out by hoisting a load to a hook 4 that can be hoisted up and down freely. The crane base 1 is adapted to be swingable on a truck 5. l represents the distance between the hoisting 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 distance between the hoisting fulcrum of the boom 2 and the axis of the tip pulley 6 of the boom 2. It represents the vertical distance of the center, that is, the working lift. 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 ΔH represents the heave angle of the boom 2. 2
represents the amount of decrease in the vertical direction of the vertical distance between the up-and-down fulcrum of the boom 2 and the six axes of the end pulley of the boom 2 when deflected due to the lifting load and the dead weight of the boom 2, hereinafter referred to as the amount of reduction in working lift.

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=lsinθ−ΔH 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 that accurately responds to the working lifting height H in consideration of the deflection of the boom 2, it is necessary to accurately grasp the working lifting head reduction amount ΔH and calculate it based on the above calculation formula.

Regarding the working lift reduction amount ΔH, (1) The working lift reduction amount 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). Since ΔH is approximately proportional to the moment generated around the fulcrum of the boom 2 due to the boom 2's own weight and the lifting load, it is the maximum working lift reduction when the rated load of the boom 2 is lifted at that time. If we know the amount ΔHmax, the moment Mmax around the boom 2 hoisting fulcrum, and the moment M generated around the boom 2 hoisting fulcrum based on the actual load currently being lifted and the boom 2's own weight, the working lift reduction amount ΔH is ΔH It can be understood as ≒ΔHmaxM/Mmax.

(2) When the boom 2 is at a certain elevation angle θ,
Rated load (varies depending on boom 2 length l)
Maximum working lift reduction amount ΔHmax when lifting
is the proportional distribution formula based on the maximum working lift reduction amount ΔH ₁ max at the boom 2 length l ₁ at the relevant heave angle θ and the maximum working lift reduction amount ΔH ₂ max at l ₁ ΔHmax = ΔH ₁ max + ΔH ₂ max - ΔH ₁ max/l
₂ −l ₁ (l −l ₁ ), it can be obtained approximately.

The maximum working lift reduction amount ΔH ₁ max, ΔH ₂ max at each heave angle may be measured or calculated for each heave angle, or the moment and the deflection angle Δθ due to the moment may be used. There is a relationship of Δθ = kM (k: constant), and since this deflection angle Δθ and the amount of working lift reduction are also proportional, we can use the length as a parameter and the horizontal axis as the heave angle θ, When considering a maximum moment curve drawn with the maximum moment Mmax on the vertical axis, this curve has the heave angle θ on the horizontal axis and the maximum working lift reduction amount Δ on the vertical axis.
It is in a proportional relationship to the maximum deflection angle curve drawn by taking Hmax, and therefore the maximum moment curve described above may be used.

Therefore, the maximum working lift reduction amount ΔH _{1 max} , ΔH 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; 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 amount of reduction in working lift ΔH can be approximately determined, and using this, the working lift H can also be determined accurately.

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 a self-moment output unit that outputs 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, that is, the response value M of the actual moment. It is composed of a load cell inserted into 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, and stores the response value Mmax of the maximum moment generated around the hoisting fulcrum of the boom 2 when the rated load is lifted in each state of the boom 2. It receives signals from the heave angle detector 10 and the detector 9 and outputs a value responsive to the maximum moment Mmax in the boom state at that time. 13 is a maximum working lift reduction amount output device, which has two different lengths l ₁ of the boom 2,
The maximum working lift reduction amounts ΔH ₁ max and ΔH 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 boom luffing angle θ at that time is determined. This outputs the maximum working lift reduction amount ΔH ₁ max and ΔH ₂ max for two boom lengths. Reference numeral 14 indicates signals θ, l,
This is a calculation unit that receives M, Mmax, ΔH ₁ max, ΔH ₂ max, and calculates and outputs a signal responsive to the working lift height H taking into account the deflection of the boom 2. The calculation of the working lift H in the calculation section 14 is performed as follows.

(1) Maximum working lift reduction amount signals ΔH 1 max, ΔH ₂ max from the maximum working lift reduction amount output unit 13 at the current heave angle θ at the lengths l ₁ and l ₂ of the boom ₂
From the length signal l from the length detector 9, the maximum working lift reduction amount in the current boom 2 state (height angle θ, boom length l) is calculated using the proportional distribution formula ΔH ₁ max + ΔH ₂ max - ΔH ₁ max/l ₂ -l ₁
Calculate based on (l−l ₁ ).

(2) Calculate M/Mmax from the actual moment response signal 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 by the calculation result in (1) above. {ΔH ₁ max+ΔH ₂ max−ΔH ₁ max/l ₂ −l
₁ (l−l ₁ )} M/Mmax is obtained. This is the working lift reduction amount ΔH occurring in the boom 2.

(3) Working lift reduction amount ΔH, which is the calculation result of (2) above,
From the heave angle signal θ from the heave angle detector 10 and the length signal l from the length detector 9, lsinθ−ΔH is calculated to generate a signal responsive to the working lift H in consideration of deflection.

The response signal of the working head H, which takes the deflection into account and is output from the calculator 14 in this way, approximates the actual working head, and for example, this output can be used to operate a display (not shown). to inform the crane operator of the exact working lift height.

In the above explanation, we have explained that the relationship between the working lift reduction amount ΔH and the response value of the moment acting around the hoisting fulcrum of the boom 2 is proportional. Other embodiments in which the amount of reduction can be determined 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 Fig. 4, the response value M of the moment acting around the hoisting fulcrum of the boom 2 is plotted on the horizontal axis, the working lift reduction amount ΔH is plotted on the vertical axis, and the hoisting angle θ of the boom 2 is taken as a parameter, and the suspended load is For example, if we change from zero to the rated load and look at the relationship between M and ΔH at this time, we get:
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 ΔH may be measured or measured. Also, in the figure, M ₁ and M ₂ are respectively when the lifting load is zero and the boom's own weight is (The value is shown when only the undulation is acting.) When the above curve is expressed by a formula, ΔH=f(M) for each undulation angle. Therefore,
This group of equations showing the relationship between M and ΔH, which change continuously, is stored in advance in a working head reduction amount output unit equipped with a calculation unit, and the signal from the heave angle detector 10 is sent to this working head reduction amount output unit. By inputting into Therefore, the working head reduction amount ΔH can be obtained.

(In the above example, the relationship between ΔH and M was stored as a continuous function in the working head reduction amount output section, but as shown by A' and B' in Fig. 5, the relationship between ΔH 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 stored in the actual moment output section. 11, the corresponding working head reduction amount ΔHx is calculated as follows: ΔHx = ΔH ₃ + (ΔH ₄ - ΔH ₃ ) x Mx - M ₃ /M ₄ - M
It can be calculated based on the proportional distribution formula of ₃ , or by rounding up to M ₄ , Δ
Even if H ₄ is rounded down to M ₃ and ΔH ₃ is rounded off, ΔH ₃ or ΔH ₄ is outputted from the working head reduction amount output section as the working head reduction amount ΔHx corresponding to Mx. good. ) (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 B in the figure. Figures 6 and 7 show the relationship between M and ΔH 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 ₄ as a parameter. Figure 8 shows the relationship between M and ΔH when the boom length is at the intermediate boom length lx _.
ΔHx, which corresponds 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 ,
Let ΔH _A and ΔH _B be the reduction in working lift for the l ₂₀ , the reduction in working lift ΔHx for the boom with luffing angle θ=θ ₁ , M=M ₀ and boom length l=lx is as follows:
It will look like this:

ΔHx≒ΔH _A +ΔH _B -ΔH _A /l ₂₀ -l ₁₀ (lx
-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 ΔH 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 , one working lift reduction amount ΔH is output, and when the boom length is intermediate boom length lx, two working lift reduction amounts ΔH corresponding to l ₁₀ and l ₂₀ are output. This is a quantity output section.
60 is each signal θ, l, Δ from the length detector 9, the heave angle detector 10, and the working lift reduction amount output unit 50.
This is a calculation unit that receives H and calculates and outputs a signal responsive to the working lift height H taking into account the deflection of the boom 2. The calculation of the working lifting height H in the calculation unit 60 will be explained based on the above-mentioned specific example, that is, the boom length is the intermediate boom length lx, the boom heave angle θ ₁ , and the moment response value is M ₀ as follows. It is done as follows.

Standard boom length from working lift reduction amount output unit 50
Upon receiving the working lift head reduction amounts ΔH _A and ΔH _B at l ₁ and l ₂ and also receiving the length signal lx from the length detector 9, the working lift head reduction amounts are calculated as ΔH _A +ΔH _B −ΔH _A /l ₂₀ -l ₁₀ (lx-l ₁₀ ).

Working head reduction amount ΔHx obtained in this way
and the length signal lx from the length detector 9, lx sin θ - ΔHx is calculated to generate a signal responsive to the working lift H in consideration of deflection.

The working lifting height H in the above explanation refers to the vertical distance from the hoisting fulcrum of the boom 2 to the axis of the tip pulley, but if the vertical distance from the ground is required, Needless to say, it can be obtained by adding the value corresponding to the distance h ₁ to the output value.

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, add a certain value h ₁ to the output value of the calculation section 14 above. It goes without saying that what is required is obtained by subtracting from something.

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 working lift reduction amount and the response value of the moment acting around the boom hoisting fulcrum, and FIG. 9 is another embodiment of the present invention. FIG. 2: Boom, 10: Boom elevation angle detector, 1
1: Actual moment output section, 9: Length detector.

Claims (1)

[Claims] 1. A method for obtaining a working lift response signal for a crane having a boom that can be freely adjusted in elevation, and the relationship between the load and the amount of reduction in the working lift of the boom that occurs based on deflection of the boom when a load is applied to the tip of the boom. is memorized in advance based on the boom luffing angle and boom length, and during actual crane work,
A working lifting head reduction amount signal is obtained based on the load signal, boom hoisting angle signal, boom length signal and the above-mentioned memory signal during the relevant work, and the working lifting head reduction amount signal is converted to the sine of the boom hoisting angle signal to determine the boom length. A method to obtain the crane's working lift response signal by subtracting from the signal multiplied by the signal.