JPS625875B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining a working radius 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 radius response signal is to calculate the boom length by multiplying it by the cosine of the boom hoisting angle. However, for long booms, 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 radius response signal is simply obtained by multiplying the cosine 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 radius. The present invention attempts to obtain a highly accurate working radius 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 determining a working radius 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 lifting 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 R represents the boom length.
represents the horizontal distance between the uphill fulcrum and the axis of the end pulley 6 of the boom 2, that is, the working radius. r represents the horizontal distance between the center of rotation of the crane base 1 and the fulcrum of the boom 2. 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 0, that is, the heave angle of the boom 2, and Δθ
is the hoisting fulcrum of boom 2 and boom 2 when boom 2 is deflected due to the lifting load and the boom 2's own weight.
represents the angle of the straight line T connecting the six axes of the distal pulley with respect to the straight line S, hereinafter referred to as the deflection angle.

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

R = lcos (θ - Δθ) Here, the length l of the boom 2 is, for example, the base end of the boom 2 is wound up on a winding drum 7 provided at the base end of the boom 2, and the tip is wound up freely and brought to the end of the boom 2. The extended length of the fixed cord 8 can be easily detected by the length detector 9 that continuously detects it, and the heave angle θ of the boom 2 without considering deflection can be easily detected.
can be easily detected, for example, by the heave angle detector 10 that detects 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. In order to obtain a signal that responds to an accurate working radius R 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 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 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 and the maximum deflection angle Δθ ₂ max at l ₂ at the relevant heave angle θ. 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 and Δθ ₂ max may be measured or calculated for each elevation angle, but between the moment and the deflection angle Δθ due to the moment, Δθ=KM (K: constant ), the maximum moment curve drawn with the length as a parameter, the horizontal axis representing the undulation angle θ, and the vertical axis representing the maximum moment Mmax, has the undulation angle θ on the horizontal axis and the maximum deflection on the vertical axis. It is in a proportional relationship to the maximum deflection angle curve drawn by taking the angle Δθmax, and therefore the maximum moment curve described above may 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 , the response value of the maximum moment Mmax generated around the lifting fulcrum of the boom 2 when the load is lifted in each state of the boom 2;
Boom 2 actually lifts due to its own weight and lifting load.
The actual moment M occurring around the fulcrum of
If the response of
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 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. It 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 interposed in the piston rod, and may be configured, for example, by a converter that converts the internal pressure of the hydraulic cylinder 3 for luffing into a hydraulic power, or A strain gauge may be attached to the boom, and the moment acting on the boom may be detected from the strain gauge.

Reference numeral 12 is a maximum moment output unit that outputs a value in response to the maximum moment, which is a response value 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.
Mmax is stored, and upon receiving signals from the heave angle detector 10 and length detector 9, it outputs a value responsive to the maximum moment Mmax in the boom state at that time. 13 is a maximum deflection angle output device that outputs the maximum deflection angles Δθ ₁ max and Δθ ₂ max for each luffing angle when the rated load is lifted at two different lengths l ₁ and l ₂ of the boom 2, respectively. After receiving the signal from the heave angle detector 10, the maximum deflection angles Δθ ₁ max and Δθ of the two boom lengths at the boom heave angle θ at that time are determined.
₂ max is output. 14 are respective signals θ, l, M,
This is a calculation unit that receives Mmax, Δθ ₁ max, and Δθ ₂ max, and calculates and outputs a signal responsive to the working radius R in consideration of the deflection of the boom 2. The calculation of the working radius R in the calculation section 14 is performed as follows.

(1) Length of the boom from the maximum deflection angle output section 13
From the maximum deflection angle signals Δθ ₁ max, Δθ ₂ max at _the current heave angle θ in l 1 l ₂ and the length signal l from the length detector 9, the boom 2 state at that time (heave angle θ, boom Proportional distribution formula for the maximum deflection angle at length l) 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 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. Then, {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 lcos(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 a working radius R that takes into account deflection.

In this way, the response signal of the working radius R that takes the deflection into account is output from the calculation unit 14 and is very close to the actual working radius.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 radius.

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
Next, another embodiment will be described in which the deflection angle can be determined more accurately than the one described above.

(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 advance in a deflection angle output unit equipped with an arithmetic unit, and the signal from the heave angle detector 10 is input to this deflection angle output unit. 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 was stored as a continuous function, but as shown by A' and B' in
and M may be remembered in a discontinuous manner,
In this case, for example, for A′, the response value of the moment stored in advance
When an intermediate value Mx between M ₃ and M ₄ is received from the actual moment output unit 11, the corresponding deflection angle Δθx is calculated as 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 as Δθ ₃
, and further rounding to Δθ ₃ or Δθ ₄
may be output from the deflection angle output section as 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, A case in which the tip boom is in an extended state and has not yet reached the state shown in B of the figure will be described. Figures 6 and 7 show the third boom with the boom length at the reference boom length l ₁₀ and l ₂₀ .
The relationship between M and Δθ corresponding to A and B in the figure is drawn using the heave angle θ ₁ as a parameter, and Figure 8 shows the relationship between M and Δθ when the boom length is at the intermediate boom length lx. The relationship between Δθ and undulation angle θ ₁
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 determining the working radius response signal in another embodiment will be described 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 each signal θ, l, Δθ of the length detector 9 and the undulation angle detector 10.
This is a calculation unit that receives the information, calculates and outputs a signal responsive to the working radius R in consideration of the deflection of the boom 2. The calculation of the working radius R in the calculation unit 60 is as follows:
Based on the above-mentioned specific example, in which the boom length is the intermediate boom length lx, the boom heave angle is θ ₁ , and the moment response value is M ₀ , the process is 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, l _x cos(θ−Δθx) is calculated to generate a signal responsive to the working radius R considering the deflection. It is something.

Note that the working radius R in the above explanation is the boom 2
It refers to the horizontal distance from the fulcrum of
Needless to say, when the horizontal distance from the center of rotation of the crane base 1 is required, it can be found by subtracting the value corresponding to the distance r from the output values of the calculation units 14 and 60.

In any case, the present invention has the excellent effect of being able to obtain a working radius response signal that is very close to the actual working radius 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 radius response signal for a crane with a boom that can be freely adjusted in elevation, in which the relationship between the deflection angle of the boom and the load that occurs when a load is applied to the tip of the boom is determined in advance for each elevation angle of the boom. 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. A method of subtracting a stored value from the heave angle signal from the boom's heave angle detector and multiplying the cosine of this subtracted value by the length of the boom to obtain the crane's working radius response signal.