JPS6225595B2 - - 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 undulation 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 undulation angle of the boom 2, and ΔR represents the undulation angle of the boom 2. represents the amount of increase in the horizontal direction of the horizontal distance between the fulcrum of the boom 2 and the axis of the end pulley 6 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 increase in the working radius.

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=lcosθ+ΔR Here, the length l of the boom 2 is, for example, a cord 8 whose base end is wound up on a winding drum 7 provided at the base end of the boom 2, and the cord 8 is freely wound up and its tip is fixed to the tip of the boom 2. The length detector 9 continuously detects the extended length of the boom 2, and the heave angle θ of the boom 2 without taking into account deflection.
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 responsive to an accurate working radius R that takes into account the deflection of the boom 2, it is necessary to accurately grasp the working radius increase amount ΔR and calculate it based on the above calculation formula.

Regarding the working radius increase amount ΔR, (1) The working radius increase amount ΔR in the state of the boom 2 in any crane operation state (the state of the boom 2 defined by the length of the boom 2 and the luffing angle of the boom) 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, so it is the maximum working radius increase when the rated load is lifted in the condition of the boom 2 at that time. If you know ΔRmax, 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 radius increase ΔR is: ΔR It can be understood as ≒ΔRmaxM/Mmax.

(2) When the boom 2 is at a certain elevation angle θ,
Rated load (varies depending on boom 2 length l)
Maximum working radius increase ΔRmax when hanging
is a proportional distribution formula based on the maximum working radius increase ΔR ₁ max at the length l ₁ of the boom 2 at the relevant heave angle θ and the maximum working radius increase ΔR ₂ max at l ₂ ΔR max = ΔR ₁ max + ΔR ₂ max - ΔR ₁ max/l
₂ −l ₁ (l −l ₁ ), it can be obtained approximately.

Note that the maximum working radius increases ΔR ₁ max and ΔR ₂ max at each undulation angle may be measured or calculated for each undulation angle, but 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 increase in working radius are also proportional, we can use the length as a parameter and the horizontal axis as the undulation angle θ, and the vertical axis as the undulation angle θ. When considering a maximum moment curve drawn with the maximum moment Mmax on the axis, this curve has the undulation angle θ on the horizontal axis and the maximum working radius increase Δ on the vertical axis.
It is in a proportional relationship to the maximum working radius increase curve drawn by taking Rmax, and therefore the maximum moment curve described above may be used.

Therefore, the maximum working radius increase amount ΔR _{1 max} , ΔR 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 hoisting fulcrum of the boom 2 when the load is lifted in each state of the boom 2
If we know the response value of Mmax; the response value of the actual moment M that is actually generated around the lifting fulcrum of the boom 2 due to its own weight and the lifting load, we can approximately determine the working radius increase ΔR. , Also, using this, the working radius R 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 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 from hydraulic to electrical. A strain gauge may be installed to detect the moment acting on the boom 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 heave fulcrum of the boom 2 when the rated load in each state of the boom 2 is lifted. It receives signals from the undulation angle detector 10 and length detector 9 and outputs a value responsive to the maximum moment Mmax in the boom state at that time. 13 is a maximum working radius increase amount output device, which outputs the maximum working radius increase amount Δ when lifting the rated load at two different lengths l ₁ and l ₂ of the boom 2.
Memorize R ₁ max and ΔR ₂ max for each undulation angle,
It receives the signal from the heave angle detector 10 and outputs the maximum working radius increases ΔR ₁ max and ΔR ₂ max for the two boom lengths at the boom heave angle θ at that time. 14 are signals θ, l, M, Mmax, and ΔR from the heave angle detector 10, length detector 9, actual moment output section 11, maximum moment output section 12, and maximum working radius increase amount output section 13. ₁ max and ΔR ₂ max, and calculates and outputs a signal responsive to the working radius R taking into account the deflection of the boom 2. The calculation of the working radius R in the calculation section 14 is performed as follows.

(1) Maximum working radius increase signal ΔR ₁ max, ΔR ₂ max at the current heave angle θ at the boom 2 length _{l 1} , l ₂ from the maximum working radius increase output unit 13
From the length signal l from the length detector 9, the state of the boom 2 at that time (height angle θ, boom length l)
Proportional distribution formula for maximum working radius increase in ΔR ₁ max + ΔR ₂ max - ΔR 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. {ΔR ₁ max+ΔR ₂ max−ΔR ₁ max/l ₂ −l
₁ (l−l ₁ )} M/Mmax is obtained. This is the working radius increase amount ΔR occurring in the boom 2.

(3) Working radius increase amount ΔR, 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, lcosθ+ΔR is calculated to generate a signal responsive to the working radius R taking deflection into consideration.

The response signal of the working radius R, which takes the deflection into account and is thus output from the calculation unit 14, approximates the actual working radius, and for example, this output can be used to operate a display (not shown). to inform the crane operator of the exact working radius.

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

(In the above example, the relationship between ΔR and M was stored as a continuous function in the working radius increase amount output section, but as shown by A' and B' in Fig. 5, ΔR and M may be stored in a discontinuous manner. In this case, for example, for A', an 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 increase in working radius ΔRx is calculated as follows: ΔRx=ΔR ₃ +(ΔR ₄ −ΔR ₃ )×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 R ₄ is rounded down as M ₃ and ΔR ₃ is rounded off, ΔR ₃ or ΔR ₄ is rounded off and output as the working radius increase amount ΔRx corresponding to Mx from the working radius increase amount output section. 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 FIG. Figures 6 and 7 show the relationship between M and ΔR 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 ₁ as a parameter. Figure 8 shows the relationship between M and ΔR when the boom length is at the intermediate boom length lx _.
ΔRx, 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 ,
If the increase in working radius for l ₂₀ is ΔR _A and ΔR _B , the increase in working radius ΔRx for a boom with luffing angle θ = θ ₁ , M = M ₀ and boom length l = lx is as follows. .

ΔRx≒ΔR _A +ΔR _B -ΔR _A /l ₂₀ -l ₁₀ (lx
-l ₁₀ ) Next, a method for obtaining a working radius 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 ΔR 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 radius increase ΔR is output, and when the boom length is intermediate boom length lx, two working radius increases ΔR 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 undulation angle detector 10, and the working radius increase amount output unit 50.
This is a calculation unit that receives R, 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 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 is θ ₁ , and the moment response value is M ₀ . It is done as follows.

From the working radius increase amount output unit 50 to the standard boom length
In response to the working radius increases ΔR _A and ΔR _B at l ₁₀ and l ₂₀ , the working radius increases are calculated based on ΔR _A + ΔR _B −ΔR _A /l ₂₀ −l ₁₀ (lx−l ₁₀ ). .

Working radius increase amount ΔRx obtained in this way
From the length signal lx from the length detector 9, lxcosθ+ΔRx is calculated to generate a signal responsive to the working radius R in consideration of deflection.

Note that the working radius R in the above description refers to the horizontal distance from the fulcrum of the boom 2, but if the horizontal distance from the swing center of the crane base 1 is required, the calculation unit 14, Needless to say, it can be obtained by subtracting the value corresponding to the distance r from the output value of 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 working radius increase 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 determining the working radius response signal for a crane with a boom that can be freely adjusted in elevation, and the relationship between the increase in the working radius of the boom and the load that occurs based on the 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 radius increase signal is obtained based on the load signal, boom hoisting angle signal, boom length signal and the memory signal during the work, and the working radius increase signal is converted to the cosine of the boom hoisting angle signal to determine the boom length. A method of determining the crane's working radius response signal by adding the product multiplied by the signal.