JPS63359B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for generating a rated load signal for a crane.

The rated load of the crane differs depending on the extension amount and the levitation angle of the multi-stage boom. It is virtually impossible to memorize all of these different load ratings, so the following methods are used today.

The boom length of the multi-stage boom is the standard boom length (this standard boom length is, for example, 3 mm as shown in Figure 1).
In a three-stage sequentially retractable boom consisting of three boom cylinders, the intermediate boom is completely inserted into the base boom as shown in A, the tip boom is completely inserted into the intermediate boom, and the intermediate boom is completely inserted into the base boom as shown in B. A boom in which the end boom is fully extended with respect to the end boom, and the tip boom is fully inserted into the intermediate boom, and the intermediate boom is fully extended with respect to the base boom, and the tip boom is fully extended with respect to the intermediate boom, as shown in C. Describe the length. ), the relationship between the hoisting angle and the rated load of the multi-stage boom is stored in the function generator for each reference boom length, and when the hoisting angle signal is input to the function generator as an input signal, the hoisting angle signal is A corresponding rated load signal is output as an output signal.

The relationship between the undulating angle and the rated load in each of the states A, B, and C stored in this function generator is shown. The performance characteristic diagram is shown in Figure 2.
Each of F corresponds to each of A, B, and C above.

With this method, when the boom length is the standard boom length, an accurate load rating can be obtained, but when the boom length is a non-standard boom length between adjacent standard boom lengths, In some cases, it is assumed that the boom is in the state of the longer reference boom length among the adjacent reference boom lengths, and the rated load signal of this longer reference boom length is set as a function when the luffing angle signal is input. A generator is being generated. In this way, when the boom length is in a non-standard boom length state, the rated load of the standard boom length one rank lower is used, so there is a problem that the lifting ability of the crane cannot be fully demonstrated.

This problem will be explained using a specific example.

When the intermediate boom is slightly extended from state A in Figure 1 (hereinafter referred to as the current state), the first
The conventional method is to use the rated load in the state shown in Figure B as a substitute. Comparing the current state and state B, in the current state, the center of gravity of the multi-stage boom is closer to the base end of the multi-stage boom, so the overturning moment due to the multi-stage boom's own weight is reduced compared to state B. Since the position of the suspended load suspended from the tip of the boom approaches the base end of the multi-stage boom, the moment arm of the suspended load is reduced, and the overturning moment due to the suspended load is reduced compared to state (B). For this reason, the current true rated load, which should be determined as the limit load to prevent the crane from tipping over, is significantly larger than the rated load substituted above, and it is said that the crane's lifting capacity is not being fully utilized with the conventional method. It was a problem.

An object of the present invention is to obtain a rated load signal generation method that generates a rated load signal commensurate with the lifting capacity of a crane when the boom length is a non-standard boom length.

In order to achieve the above object, the present invention has the following features: The proximal end of a telescoping multi-stage boom is pivotally connected to a base via a pin, and a luffing cylinder is inserted between the base and the multi-stage boom. In the crane in which the multi-stage boom is controlled to raise and lower, the multi-stage boom is fully retracted and fully extended, and a specific intermediate extension determined at an intermediate boom length from the fully retracted state to the fully extended state. The moment generated around the above pin based on the rated load and the boom's own weight when the rated load is suspended at an arbitrary boom heave angle for each reference boom length, with each condition set as the standard boom length condition. A value responsive to is stored in advance as a memory value, and when the multi-stage boom is in a state of a non-standard boom length that is intermediate between adjacent standard boom lengths, a longer standard among the adjacent standard boom lengths is stored in advance. Select the memorized value corresponding to the boom length, calculate the moment from this memorized value based on the memorized value thus selected, and calculate the moment generated around the above pin based on the dead weight of the boom from this moment. The first limit load obtained by dividing this reduced value by the arm length of the moment around the pin due to the above rated load was compared with the second limit load based on the strength stored in advance. Since the smaller load is later generated as the rated load signal, the present invention exhibits superior effects compared to the conventional example described above.

In other words, referring to the above-mentioned example, when the intermediate boom is in the current state where it has been extended by a small amount from the state shown in FIG. This is the present invention, and when comparing the moment around the pin due to the self-weight of the multi-stage boom in state B and the moment around the pin due to the self-weight of the multi-stage boom in the current state, state B shows that the intermediate boom Since the moment is large enough to correspond to the amount of extension, in the current state, the moment is increased by an amount corresponding to the moment difference and the decrease in the moment arm due to the hanging load position approaching the base end of the multi-stage boom. A load larger than that of the conventional example becomes the first limit load, and the crane capacity can be fully utilized.

In addition, in this invention, even if the first limit load obtained as described above is lower than the limit load value for preventing the crane from overturning, the swivel base, which is each component constituting the crane, cannot be rotated. In order to prevent damage to equipment, multi-stage boom telescoping devices, multi-stage booms, etc., this second critical load is memorized in advance because it may exceed the second critical load determined as the critical load based on strength. This second limit load and the first limit load are compared, and the smaller one is generated as the rated load signal, which is safe.

Next, the present invention will be explained in detail based on a specific example.

FIG. 3 is an overall side view of the crane, which will be described below.

1 is a base, and this base 1 is rotatably mounted on a vehicle body 2. Reference numeral 3 denotes an outrigger device, which extends to the left and right sides of the vehicle body 2 and supports the vehicle body 2 as shown in FIG. 3 during crane work. 4 is a multi-stage boom, and the base end of the multi-stage boom 4 is pivotally attached to the base 1 via a pin 5. Reference numeral 6 denotes a hoisting cylinder inserted between the base 1 and the multi-stage boom 4, and the multi-stage boom 4 moves up and down by its expansion and contraction. 7 is a winch drum installed on the base 1, and the rope 8 pulled out from the winch drum 7 passes through a pulley 9 installed at the tip of the multi-stage boom 4, and then is attached to the hanging tool 1.
It has reached 0. Reference numeral 11 denotes a sensor provided on the piston rod of the raising cylinder 6, which detects as an output voltage a value responsive to the moment caused by the boom's own weight and the weight W of the suspended load generated around the pin 5, based on the distortion of the piston rod. . The fourth part shows the relationship between the undulation angle and the output voltage when the rated load is suspended as the weight of the suspended load.
FIG. 4 is a performance characteristic diagram of FIG. 4, in which states A, B, and C correspond to states G, J, and I in FIG. 4, respectively.

20 is a boom length detector installed at the base of the multi-stage boom 4, and one end of the cord 20', which is wound around a drum that is always urged to rotate in one direction by a spiral spring, is fixed to the tip boom. The drum is forcibly rotated against the spiral spring by the extension of the tip boom, and the length of the boom is detected from the rotation of the drum. 21
is a boom hoisting angle detector installed at a suitable location on the base end of the boom.

Next, the fifth section on how to determine the first limit load.
This will be explained based on FIG.

Fig. 5 shows the relationship of the force applied to the multi-stage boom with respect to the straight line (hereinafter referred to as the central axis line) connecting the center point of the pin 5 of the multi-stage boom 4 and the center point of the pulley 8 in Fig. 3. . Each symbol in this figure has the following meaning.

A: Center point position of the pivot pin that pivots the hoisting cylinder 6 to the base 1 B: Center point position of the pin 5 D: Center point position of the pivot pin that pivots the hoisting cylinder 6 to the multistage boom 4 l ₁ : Distance from the above symbol B to the center point position of the pulley 9 l ₂ : Straight line distance parallel to the central axis line from the above symbol B to the point on which the dead weight W _B of the multistage boom 4 acts, that is, the center of gravity l ₃ : Straight line distance parallel to the central axis from code B to code D above a: Distance between code A and code B b: Distance between code B and code D c: Distance between code D and code A θ: Multistage Raising angle β of boom 4: Angle α between the straight line connecting symbols B and D and the central axis line α: Angle η between the straight line connecting symbols B and A and the horizontal line η: Symbol B Angle F between the straight line connecting code A and the straight line connecting code A and code D: Reaction force of the undulation cylinder h: Vertical distance from code B to the undulation cylinder 6 Each code is determined in this way At this time, the moment exerted by the hoisting cylinder 6 around the pin 5, which is the pivot point of support of the multistage boom 4, can be expressed as F×h − .

Based on the self-weight W _B of the multi-stage boom, the multi-stage boom 4
The moment generated around pin 5, which is the pivot support point of , can be expressed as W _B ×l ₂ cosθ − .

Based on the hanging load amount W, the moment generated around the pin 5, which is the pivot support point of the multistage boom 4, can be expressed as W×l ₁ cosθ − .

From the balance of the moments mentioned above, it can be expressed as F×h=Wal ₂ cosθ+Wl ₁ cosθ − . If the equation is further modified, it can be expressed as W=F×h−W _B l ₂ cosθ/l ₁ cosθ − .

Here, l ₁ can be determined from the boom length detector 20 described above, and θ can be determined from the heave angle detector 21 described above. W _B l ₂ cos θ changes each time as W _B , l ₂ , and cos θ change as the length of the multistage boom and the undulation angle change, but as shown below. , it can be easily calculated without having to memorize it individually.

That is, the hanging load is set to zero, the multi-stage boom is placed in a horizontal state, and the multi-stage boom length is changed from the most contracted state to the most extended state, and the pivoting of the multi-stage boom 4 is performed as the multi-stage boom length changes at this time. If the value of the moment around the pin 5, which is the support point, is calculated and stored for each length of the multi-stage boom based on the reaction force of the hoisting cylinder 6 or from a theoretical calculation formula, the value of the moment around the pin 5, which is the support point, can be calculated and stored for each length of the multi-stage boom. The moment value due to self-weight at any undulation angle can be obtained by multiplying the stored moment value by the value of cos θ. h is a function of the variable θ, as described below, and can be calculated by the calculation unit by determining θ.

That is, Furthermore, F is the value of the reaction force F of the hoisting cylinder when the boom length is set to a constant reference boom length, the boom's hoisting angle is changed, and the rated load is lifted for each hoisting angle. 1
1 or by calculation and memorize it.

Next, explanation will be given using the block diagram of FIG. 3
0 is a first calculation section, which includes a boom length detector 20,
Upon receiving the signal from the boom hoisting angle detector 21
This is to calculate l ₁ cosθ. Reference numeral 31 denotes a second calculating section, which receives signals from the boom length detector 20 and the boom heave angle detector 21 and calculates W _B l ₂ cos θ. Reference numeral 32 denotes a third calculation unit which receives a signal from the boom elevation angle detector 21 and calculates h. 33 is a memory value output unit, which includes a boom length detector 20 and a boom elevation angle detector 2.
1 and outputs the value of F stored in advance for each reference boom length. 34 is a fourth calculation unit which receives signals from the third calculation unit 32 and the stored value output unit 33,
This is to calculate F×h. Reference numeral 35 denotes a fifth calculation unit, which receives the calculation result signals from each of the calculation units 30, 31, and 34, calculates Fh−W _B l ₂ cosθ/l ₁ cosθ, and calculates the first limit load. This is what you get.

Further, the second limit load is stored in the memory device 40, and this second limit load is stored in the boom length detector 2.
0, which is obtained from the memory 40 in FIG. 8 based on the signal from the boom heave angle detector 21. Then, the first limit load and the second limit load are compared, and the smaller load is generated as the rated load signal.

As described above, the present invention has the advantage that the rated load commensurate with the lifting capacity of the crane can be obtained, so that the range of cargo handling operations can be further expanded compared to the conventional crane.

[Brief explanation of the drawing]

Figure 1 shows the multi-stage boom, A shows the multi-stage boom fully retracted, B shows the intermediate boom fully extended, C shows the multi-stage boom fully extended, and Figure 2 shows the crane. Performance characteristic diagram, Figure 3 is a side view of the crane, Figure 4 is a performance characteristic diagram showing the force applied to the hoisting cylinder, Figure 5 is an explanatory diagram showing the relationship between the forces acting on the hoisting cylinder, and Figure 6. FIG. 2 is a block diagram showing how to determine the first limit load. 4: Multi-stage boom, 5: Pin, 11: Lifting cylinder.

Claims (1)

[Scope of Claims] 1. The base end of a telescoping multi-stage boom is pivotally connected to a base via a pin, and the multi-stage boom is raised and lowered by a hoisting cylinder inserted between the base and the multi-stage boom. In the crane that is configured to control, the reference boom is set to a fully retracted state and a fully extended state of the multi-stage boom, and a specific intermediate extension state determined at an intermediate boom length from the fully retracted state to the fully extended state, respectively. Set as the length state, and set the value that responds to the moment generated around the above pin based on the rated load and the boom's own weight when the rated load is suspended at an arbitrary boom lifting angle for each of the reference boom lengths. The value is stored in advance as a memory value, and when the multi-stage boom is in a state of a non-standard boom length intermediate between adjacent standard boom lengths, the value corresponds to the longer standard boom length among the adjacent standard boom lengths. Select the memorized value to After comparing the first limit load obtained by dividing the value obtained by the arm length of the moment around the pin due to the above rated load with the second limit load based on the strength that has been memorized in advance, select the smaller of the two. A method for generating a rated load signal for a crane, characterized in that the rated load signal is generated as a rated load signal.