JP2639119B2 - crane - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a crane for a truck crane, an aerial work vehicle, and the like. The present invention relates to an apparatus provided with an alarm system for preventing a danger of falling.

[Background Art] For example, in a high-altitude work vehicle, a moment exceeding a restoring moment acts on the load and the length of expansion and contraction of the boom, and the angle, and there is a risk that the crane may fall. For this reason, the extension length of the boom, the up-down angle of the boom, and the load on the winch are detected, the overturning moment due to the load is calculated, and it is checked whether or not the overturning moment is within the use area where there is a danger of overturning. There is one in which a dangerous work state is avoided (Japanese Patent Laid-Open No. 59-114299).

[Problems to be Solved by the Invention] However, the above-mentioned fall prevention system does not have a function of judging whether or not the calculation of the fall moment is correctly executed, and thus has a problem in reliability. Once a fall accident occurs in such a work vehicle, it is inevitable that it will cause enormous damage, and in order to give top priority to accident prevention measures,
It is necessary to check whether the calculation of the overturning moment is performed correctly before, during or after the work according to the change of the work condition.

Therefore, the present invention has a function that can automatically detect that the working condition is approaching the danger area of falling and issue an alarm to prevent a falling accident, and further determine whether the function is operating normally. Provide a function to check,
It is an object of the present invention to provide a crane with an improved fall prevention function.

[Means for Solving the Problems] The present invention employs the following configuration in order to solve the above problems.

That is, the crane according to the present invention includes a boom that performs expansion / contraction / raising / lowering operations, an outrigger for supporting a moment acting on the boom, and detects a boom raising / lowering angle and a load acting on the boom raising / lowering cylinder. The crane that determines whether or not it is in the safe use area by calculating the overturning moment of the crane body and calculating the reaction force that the outrigger receives from the installation surface according to the boom up-and-down state Detecting means, calculating means for calculating the overturning moment of the crane body based on the detection signal from the reaction force detecting means, and comparing means for comparing the overturning moment calculated by the calculating means with the overturning moment are provided. It is characterized by the following.

[Action] Both the overturning moment and the overturning resistance of the crane main body are calculated according to the change in the lifting load and the state of the expansion and contraction of the boom. Both moments are equal when the boom tilt direction matches the outrigger overhang direction. Therefore, it is possible to determine whether the overturning moment is within the overturn limit by judging whether the two moments are equal or not by the comparing means. It is possible to confirm the reliability of the determination.

FIG. 1 is a block diagram schematically showing a configuration of a truck crane according to an embodiment of the present invention. A boom 2 of a truck crane main body 1 and a boom cylinder for supporting the boom and adjusting the boom angle. 3, a boom angle detector 5 for detecting an angle between the boom 2 and the vertical direction, and a boom support pressure detector 6 for detecting a pressure acting on the boom cylinder 3 are provided. The boom angle detector 5 is configured to detect an angle by a rotation sensor or a stroke of the cylinder 3. The boom support pressure detector 6 detects F acting on the cylinder as F = P × S (P is hydraulic pressure, S is piston area). Also, as shown in FIG. 2, the bogie is provided with outrigger cylinders 7, 7 'for supporting a moment acting on the entire boom including a suspended load, and a force acting on the cylinders 7, 7' is installed. An installation surface reaction force detector 8 that detects the surface reaction force is provided. The installation surface reaction force detector 8 detects the force acting on the cylinder as Po × So or Po ′ × So
(Po, Po 'are hydraulic pressure, So is piston area). In addition, as the installation surface reaction force detector 8, the above Po, Po '
Instead of measuring the load, the load can be directly measured using a load cell.

Detection signals from the boom angle detector 5 and the boom support pressure detector 6 are input to the CPU 13 via the A / D converters 9 and 10 and stored in the RAM 15. In the CPU 13, the overturning moment due to the weight is calculated by the arithmetic processing program stored in the ROM 14 based on these two data as described later. The CPU 13 determines whether the calculated overturning moment is within the overturning limit, and when it is determined that the overturning limit is approaching, an alarm signal is provided to the alarm 18 provided on the crane operation panel 17 via the I / O 16. To notify the worker that the working state is near the overturn limit area.

On the other hand, a detection signal from the installation surface reaction force detector 8 is input to the CPU 13 via the A / D converter 11, and the overturning moment is calculated. In a state where the boom is inclined in the direction in which the outrigger extends, it is determined whether or not the overturning moment matches the overturning moment, and whether or not the output of the alarm signal is reliable. In this way, the reliability of the system is confirmed.

As shown in Fig. 2, the overturning moment Ma due to the weight can be obtained by calculation if various quantities are determined.
The product is represented by a product WaLa of a weight Wa obtained by adding the boom own weight and the hanging load, and a distance La from the center of the column 20 to a center of gravity obtained by adding the boom own weight and the hanging load. Also, reduce the weight of the crane
If the distance from the center of the column to the pedestal is Lo, the restoring moment due to its own weight can be expressed as woLo, WoLo>
In WoLa, the crane will not fall. Therefore, the overturn limit is when WoLo = WaLa. On the other hand, assuming that the force acting on the cylinder 3 is F, the angle between the cylinder rod and the perpendicular is β, the angle between the boom and the perpendicular is α, and the distance between the column center and the cylinder rod action point is Lb, Becomes

In addition, between the angles α and β, in △ OAB shown in FIG. 3, ▲ and 一定 are constant, ∠AOB = 180 ゜ −α, ∠ABH = 90 ゜ −∠BAO = 90 ゜ −β , ∠ABH = tan ^-1 (▲ ▼ / ▲ ▼), Than, There is a relationship. Therefore, by detecting the boom angle α and the pressure P of the boom support cylinder, the overturning moment WaLa due to the weight can be obtained from the equations (1) and (2). Instead of detecting the angle α, the angle β may be detected.

By determining whether or not the falling moment WaLa is within the falling limit WoLo, an alarm symbol is output. The alarm based on the alarm symbol is performed by operating an alarm buzzer or an alarm lamp installed on the operation panel 15. As the processing of the alarm signal, if the value of WoLo is set to 100% and the value of WaLa is displayed on a display, it can be configured as a danger meter.

 On the other hand, the overturning resistance Mo is obtained as Mo = PoSo × Lo−Po′So × Lo = Loso (Po−Po ′).

As shown in FIG. 2, when the inclination direction of the boom coincides with the extension direction of the outrigger, Ma = Mo, and when the calculated values Ma and Mo have the same value, the calculation is correct. That is, it can be confirmed that the overturn prevention system is operating normally. Therefore, the operator can confirm that the alarm signal for preventing the overturn is normally output only by tilting the boom in the outrigger direction before the operation. As described above, in the embodiment of the present invention, it is possible to automatically determine whether the working state is in the danger area of the crane falling without relying on a human check of the worker, and the crane is provided to the worker. Since the danger of falling is warned in advance, it is possible to prevent a dangerous work state from being reached. In addition, since the arithmetic processing is performed by the CPU, the arithmetic processing can be performed in consideration of the influence of the inclination and strength of the ground at the installation location of the crane, and an alarm is issued according to the use situation to avoid a dangerous state. It is also possible to check whether or not the function of issuing the alarm is operating normally, and it is possible to further improve the reliability of the fall prevention.

In the above explanation, a truck crane was taken as an example,
The same applies to ship cranes and other various cranes that may be overturned.

[Effects of the Invention] As is clear from the above description, according to the crane according to the present invention, the danger of falling in the working state is automatically detected promptly without depending on the human check of the worker, and the warning is issued. Function to prevent the occurrence of a fall accident and perform safe work.Also, it is also possible to check whether the alarm function is working properly according to the work situation This has made it possible to further improve the reliability of safe work.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIGS. 2 and 3 are diagrams for explaining the principle for performing arithmetic processing. 2 ... boom, 3 ... support cylinder, 5 ... boom angle detector, 6 ... boom support pressure detector, 8 ... installation surface reaction force detector, 13 ... CPU (overturning moment and overturning calculation Processing and judgment means)

Claims (1)

(57) [Claims] A crane body for detecting a boom up / down angle and a load applied to a boom up / down cylinder, the boom including an outrigger for supporting a moment acting on the boom; Reaction force detecting means for detecting a reaction force received by the outrigger from the installation surface according to the up-and-down state of the boom, in a crane which is configured to determine whether or not the vehicle is in the safe use area by calculating and calculating the overturning moment of A calculating means for calculating the overturning moment of the crane main body based on a detection signal from the reaction force detecting means; and a comparing means for comparing the overturning moment calculated by the calculating means with the overturning moment. Crane.