JPS6215475B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crane working radius calculation device. Conventional equipment usually determines the working radius from the output of the boom length detector and boom inclination detector attached to the base of the telescopic boom, but for large cranes with a maximum boom length of several tens of meters, Due to the bending deflection of the boom due to the lifting load and the boom's own weight, and the deflection due to the play in the insertion part between each boom tube,
Cases arise where the working radius increases significantly over the value determined with conventional equipment. If the actual working radius increases from the calculated value, when lifting a load with the rated load set for the calculated working radius, the increased moment arm length may cause the crane to fall over, resulting in a safety issue. This will cause problems.

To prevent this, if you increase the margin of lifting performance when setting the rated load, the lifting performance will decrease evenly over the entire working radius, but the difference between the actual working radius and the calculated value will be Since it varies greatly depending on the degree of inclination, boom length, etc., the lifting performance may be unnecessarily reduced, leading to a decline in the performance of the entire crane.

The present invention addresses this problem and aims to make the working radius substantially equal to the actual value, regardless of the degree of extension or inclination of the boom.

The present invention includes installing boom inclination detectors at the base and tip of the telescopic boom, respectively, and providing a calculator for calculating the working radius by using the average value of the outputs of both boom inclination detectors as the inclination of the entire boom. This is a characteristic feature.

The figure shows an embodiment of the present invention, in which a telescopic boom 1 has four boom tubes 2, 3, 4, and 5 fitted in order in a telescopic manner, and the base end boom tube 2 is similar to the conventional one. The base end is pivotally mounted on a swivel base 6 of a truck crane by a foot pin 7, and is adjustable in elevation by a derrick cylinder 8. 9 is a boom inclination detector attached to the base of the proximal boom tube 2; 10
1 shows boom inclination detectors attached to the tip of the tip boom cylinder 5, each of which includes a weight pendulum and a cosine potentiometer operated by the pendulum. Reference numeral 11 denotes a boom length detector attached to the proximal boom cylinder 2, which includes a cord reel that constantly winds and activates the cord 12 whose end is fixed to the tip of the boom, and a potentiometer that is interlocked and connected to the rotating shaft of the cord reel. Equipped with a yometer.

13 is a working radius calculator, and a multiplication circuit 14 for multiplying the output of the boom inclination detector 9 (the cosine of the inclination angle θa of the boom base) and the output L of the boom length detector 11;
, a multiplication circuit 15 for multiplying the output of the boom inclination detector 10 (the cosine of the inclination angle θb of the boom tip) by the output L, and a circuit 16 for calculating the average value of the outputs of both multiplication circuits 14 and 15. The output of the circuit 16 is transmitted to a safety device 17 that stops the operation of the crane in the direction of increasing the overturning moment when overloaded, a working radius indicator 18, etc.

According to the above configuration, the output of the calculator 13 is the working radius R calculated by setting the inclination angle of the entire boom as θa.
is the average value of the working radius calculated by taking the inclination angle of the entire boom as θb. Generally, the inclination or inclination angle α of the boom's elastic line 0 increases at an accelerating rate as it reaches the boom tip, and at the boom tip, Since it is approximately proportional to the square of the boom length, the angle θb is the angle θ
a, and therefore the output of the calculator 13 is the actual working radius (R+
ΔR). In other words, the working radius is calculated to be slightly larger than the actual value on the safe side.

The case where the boom inclination is detected as the cosine of the boom inclination angle has been described above, but the boom inclination may also be detected as the boom inclination angle by a potentiometer. In this case, both boom inclination detectors 9 and 10 The average value of the detected boom inclination angles is calculated, and this is used as the inclination angle θ of the entire boom to calculate the working radius in the same manner as before.

According to the present invention, regardless of changes in the bending deflection of the telescopic boom due to the degree of extension and inclination of the telescopic boom and the magnitude of the lifting load, the working radius of the crane is always approximately equal to the actual value, and moreover, it is less than or equal to the actual value. Since the calculation is made slightly larger, it is possible to safely lift the load at the full rated load at all times, and moreover, there is an effect that the margin of lifting capacity provided when setting the rated load can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a side view, and FIG. 2 is a block diagram of the arithmetic unit. 1... Telescopic boom, 9, 10... Boom inclination detector, 11... Boom length detector, 13... Arithmetic unit.

Claims (1)

[Scope of Claims] 1. A calculator for calculating the working radius by attaching boom inclination detectors to the base and tip of the telescopic boom, and using the average value of the outputs of both boom inclination detectors as the inclination of the entire boom. A crane working radius calculation device characterized by: 2. The crane working radius calculation device according to claim 1, wherein the boom inclination detector is configured such that its output is the boom inclination angle with respect to a horizontal plane. 3. The crane working radius calculation device according to claim 1, wherein the boom inclination detector is configured such that its output is a cosine of the boom inclination angle with respect to a horizontal plane.