JPS6339518B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for determining the working radius of a crane.

The working radius of a crane is determined by the boom length and boom luffing angle, but when a load is suspended from the boom, such as during lifting work, even if the boom length is constant, the working radius will change due to the elastic deflection of the boom. It will change. Therefore, in the past, this elastic deflection was taken as a function of the boom length, and by using this function, the working radius was obtained by correcting the above deflection, and the rated load was read out from a pre-stored rated load curve. A safety device is used that detects an overload condition by comparing the rated load and the hanging load and generates an alarm signal.

However, the deflection of the boom is not only a function of the boom length, but is also greatly affected by the force applied to the tip of the boom, that is, the lifting load, and therefore conventional safety devices do not completely take the deflection of the boom into account. However, the backlash in each boom stage was not taken into account. Therefore, since a working radius smaller than the actual working radius is calculated and the rated load is read out based on this calculation, there is a risk that a dangerous situation may occur without an alarm being issued.

Furthermore, even if the rated load is determined in consideration of the maximum hanging load, the safety factor of the rated load must also be considered large, which substantially reduces the crane's working capacity.

The present invention has been made in view of the above, and the present invention has been developed to adjust the effective working radius of the boom by correcting changes due to mechanical play of the boom in addition to the elastic deflection of the boom when a load is applied to the boom such as during crane lifting work. The present invention provides a working radius calculation device that calculates a working radius using a function calculation using length, boom luffing angle, and hanging load as parameters.

The present invention will be explained in detail below with reference to embodiments of the accompanying drawings.

FIG. 1 shows a crane section of a crane truck, and this crane section 1 has a revolving body 2 and a boom 3 connected to this revolving body 2 via a rotation axis O, and this boom 3 is The length L is expanded and contracted, and the boom elevation angle θ is controlled by a boom cylinder (not shown). When the boom is not suspended, that is, when there is no load, the center line of the boom coincides with the axis However, in the suspended state, the center line of the boom 2 is displaced from the axis x as shown in the figure, so the actual working radius becomes R', which increases by ΔR. Therefore, the second
According to the load rating curve shown in the figure, the actual load rating decreases by ΔW corresponding to the amount of change ΔR in the working radius.

Next, the principle for determining the amount of change in the working radius caused by boom deflection and rattling between each stage of the boom from the boom length, boom heave angle, and hanging load will be explained with reference to FIGS. 3 to 5. First, the third
The figure shows the form of boom deflection caused by the boom's own weight and hanging load. When the boom heave angle θ is 0, the first boom 11, the second boom 12, and the third boom 1
The sum Δx of the deflection of each boom in step 3 is given by the following equation (2) since the entire boom can be considered as one elastic body and the elastic coefficient can be expressed as a function ₁ (L) of the boom length L. It will be done.

Δx= ₁ (L)×Wv (2) Function ₁ in the above equation (2) is easily determined from the boom material and shape.

In the above formula (2), W _v is the component of the hanging load W in the direction perpendicular to the boom tip.

Deflection Δx of the boom when the boom luffing angle θ
Assuming that the amount of change in the working radius caused by ΔR 1 is ΔR ₁ , ΔR ₁ is expressed by the following equation (3) from FIG.

ΔR ₁ = Δx×sinθ = ₁ (L)×Wcosθ×inθ...(3) In other words, in Fig. 4, the angle θ' between the direction of W and the direction of _Wv is smaller than the boom heave angle θ. However, since the boom length L is L≫△x, it is approximated as θ′≒θ, so W _v =
It is approximated that Wcosθ′≒Wcosθ.

Therefore, the amount of change ΔR ₁ can be expressed as in the above equation (3).

The amount of change in the working radius due to rattling is determined by the clearance at the sliding portion between each boom and the boom length at that time, and is therefore a function only of the boom length L. In other words, if the amount of change due to the above movement when the boom heave angle is 0 is Δy as shown in Fig. 5, it can be expressed as Δy = ₂ (L) ...(4), and this function ₂ is a function of the boom design. It is determined by the dimensions. Further, when the boom heave angle is θ, the working radius increment ΔR ₂ due to Δy is as follows.

ΔR ₂ = ₂ (L) × sin θ ... (5) Therefore, the amount of change ΔR in the working radius due to boom rattling and deflection is ΔR = ΔR ₁ + ΔR ₂ = ₁ (L) × Wcos θ × sin θ + ₂ (L) ×sin
θ = sin θ × ( ₁ (L) × Wcos θ + ₂ (L))
...(6) and can be easily calculated from the parameters L, θ, and W.

FIG. 6 shows a block diagram of an embodiment of the working radius calculation circuit according to the present invention using the above principle.
The boom length detector 21 outputs a boom length signal L ₀ corresponding to the boom length L, and the boom heave angle detector 22 and load detector 23 output a boom heave angle signal θ ₀ and a hanging load signal W ₀ , respectively. do.

The boom heave angle signal θ ₀ is converted into a cosine signal cos θ ₀ by the cosine function generator 26 and applied to one input of the multiplier 31 . A hanging load signal W ₀ is added to the other input of the multiplier 31 . This multiplier 31 outputs a multiplication signal W ₀ ×cosθ ₀ . The first function generator 28 generates a signal F ₁ corresponding to function ₁ (L ₀ ) when the boom length signal L ₀ is applied. This signal F ₁
is multiplied by the signal W ₀ ×cosθ ₀ in the multiplier 32, and the multiplier 32 outputs the signal W ₀ ×cosθ ₀ ×F ₁ , which is then added to one input of the multiplier 33. A sine signal sinθ ₀ of the boom heave angle outputted from the sine function generator 25 is added to the other input of the multiplier 33 .
Signal output from multiplier 33 F ₁ ×W ₀ ×cosθ ₀ ×
sinθ ₀ (=S) is a signal indicating the amount of change in working radius ΔR ₁ due to deflection shown in equation (3).

Further, the signal S ₂ corresponding to the working radius change amount ΔR ₂ due to the backlash shown in equation (4) is the signal F ₂ corresponding to the function ₂ (L ₀ ) sent from the second function generator 27.
sinθ ₀ by multiplier 34. The signals S ₁ and S ₂ are added by an adder 35 to obtain a signal S (=S ₁ +S ₂ ) representing the amount of change ΔR in the working radius due to warp and deflection.

Furthermore, by adding the signal of the working radius R of the above equation (1) to the signal S, the corrected substantial working radius can be obtained. In other words, the boom length is determined by the multiplier 30.
L ₀ is multiplied by the signal cos θ ₀ , and the attenuator 36 subtracts the distance A signal generated from the distance generator 24 from the multiplied signal L ₀ ×cos θ ₀ to obtain the signal L ₀ ×cos θ ₀ -A. This signal L ₀ ×cos θ ₀ -A is added to the signal S in an adder 31, and a working radius signal is output from the terminal _TR .

This working radius signal S is used to obtain the rated load from a storage device that stores the rated load curve or from a function generator, and a warning of a dangerous situation is issued by comparing the rated load and the hanging load signal.

In the above embodiment, the working radius signal S is obtained by an arithmetic circuit, but the present invention is not limited to this. For example, a microcomputer or the like may be used, and in short, it is a device that substantially performs the calculation of equation (6). That's fine.

According to the present invention, the amount of change in the working radius based on the deflection and play of the boom can be determined with high accuracy, and the true working radius can be obtained in which this amount of change is taken into account.

Therefore, if applied to a safety device that uses the working radius as a parameter, the reliability of the device can be significantly improved.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a crane vehicle, Figure 2 is a rated load curve diagram of the crane, Figures 3 and 4 are side views showing how the working radius changes due to deflection of the boom, and Figure 5 is a diagram of the crane's rated load curve. FIG. 6 is a block diagram showing an example of a working radius calculation circuit according to the present invention. 21...Boom length detector, 22...Boom elevation angle detector, 23...Load detector, 24...Distance generator, 2
7...Second function generator, 28...First function generator, 3
0, 31, 32, 33, 34... Multiplier, 35, 3
7...Adder, 36...Subtractor.

Claims (1)

[Claims] 1. A boom length detection means for detecting the boom length, an angle detection means for detecting the boom heave angle, a load detection means for detecting the suspended load, and performing work based on the boom length and the boom heave angle. means for determining the radius; first function generating means for determining the elastic modulus of the boom using the boom length as a variable; a second function generating means for determining the boom length as a variable; a means for determining the amount of change in the working radius due to deflection of the boom based on the elastic modulus, the hanging load and the boom heave angle; means for determining the amount of change in the working radius due to the above-mentioned changes based on the displacement of the tip of the boom and the radius boom luffing angle, and calculating the true working radius by correcting the working radius with each of the above-mentioned changes A working radius calculation device comprising means.