JPH01256497A - Load vibration preventer at time of ungrounding of slinging load of crane with telescopic boom - Google Patents

Abstract

PURPOSE:To perform safety operation by detecting load acting on a boom, its length and a derricking angle of the boom, outputting an operating signal, and offsetting an increase in an operating radius due to deflection of the boom after starting in a way of shortening the boom to some extent. CONSTITUTION:A boom 3 is controlled so as to cause a hook H at a tip of a wire hung down from a tip of the boom 3 to be reached to a spot just above a load W. A derricking angle of the boom 3 and its length at the time is detected, and an operating radius R0 is operated and stored. Next, the load W is slightly slung up and its weight is detected by a sensor, inputting it into an operational part which finds the operating radius R0 to be increased by deflection of the boom 3. Such a contraction value of boom length as causing a difference R=RX-R0 to be zero is dound, thereby shortening length of the boom 3. With this constitution, vibration at the time of ungrounding of the load W is reduced, thus any possible danger is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is a device for preventing load swing when a crane having a telescoping boom is off-loading.

(Prior art) In a crane having a telescoping boom, a load placed on the ground is hung from a load hook that is suspended from the tip of the telescoping boom or the tip of a supplementary jib attached to the tip of the boom so that it can be hoisted up and down. As the hoist is hoisted, the load acting on the telescopic boom gradually increases, and the telescopic boom bends accordingly, causing the tip of the telescopic boom or the tip of the refill jib to shift forward. For this reason, there is a problem in that the suspended load swings forward when it comes off the ground, which is dangerous. therefore,
When hoisting a hoisted load and taking it off the ground, the crane operator had to operate the telescoping boom to raise or lower the boom so that the tip of the boom or the tip of the supplementary jib was directly above the hoisted load. .

(Problems with the Prior Art) However, such operations are complicated and extremely difficult for the operator.

(Means for Solving the Problems) The present invention was made to solve the problems of the prior art described above, and it is necessary to operate a telescoping boom and a winch for hoisting and hoisting hooks when hoisting a load on the ground. After the hook is positioned directly above the load and the load is hung on the hook, the suspended load can be lifted off the ground without swinging by simply hoisting the hook. The object of the present invention is to provide a load swing prevention device.

In order to achieve the above object, the device for preventing load swing at unloading of a crane having a telescoping boom according to the present invention is constructed as follows.

A load swing prevention device for a crane having a telescoping boom that can be driven to extend and retract in ups and downs, including a load detector that detects the load acting on the telescoping boom, and a boom length that detects the length of the telescoping boom. a detector, a boom hoisting angle detector for detecting a hoisting angle of the telescopic boom; It is composed of a calculation unit that outputs a signal to the drive control device of the telescopic boom, and an operation signal input unit that operates the calculation unit, and the calculation unit receives the signal from the operation signal human power unit. When the operation signal is input, based on the signals from the boom length detector, boom heave angle detector, and load detector, the deflection of the telescopic boom that occurs due to the increase in the load acting on the boom after the input of the operation signal is detected. Nα of a crane having a telescoping boom, characterized in that the crane is configured to output a telescoping boom reduction drive signal to a telescoping boom drive control device in order to offset an increase in working radius.
5 Load swing prevention device when unloading.

(Function) According to this configuration, after the hook is lowered directly above the load on the ground and the load is hung on the hook, the operation signal is manually inputted from the operation signal input section to the calculation section.

Then, operate the winch for hoisting up and lowering the hook to lift the load. Then, the load acting on the telescopic boom gradually increases, and the tip of the telescopic boom or the end of the supplementary jib bends, resulting in an increase in the lifting radius. However, the telescopic boom is automatically retracted in response to a signal from the calculation unit to offset this increase in the lifting radius, so the lifting radius is automatically maintained. Therefore, there is no need for the operator to raise and retract the telescopic boom at the time of breaking the ground.

(Example) Fig. 1 and Fig. 2 are explanatory diagrams of a crane having a telescopic boom, in which 1 is a vehicle, 2 is a swivel base mounted on the vehicle 1 that can be freely swiveled, and 3 is a no. 6. A telescopic boom that is pivotally mounted so that it can be raised and lowered, and is driven to be raised and lowered by the raising and lowering cylinder 4.

5 is a telescopic cylinder for telescopically driving the telescopic boom 3. A hook H is suspended from the tip of the telescopic boom 3 so as to be able to be hoisted up and down. The hook H is driven up and down by a hydraulically driven winch 6 provided on the swivel base 2. Reference numeral 7 denotes a drive control device for the telescopic boom 3, which includes an undulating control valve 8 and a telescopic control valve 9, which are positioned at the same pressure on all sides. The undulation control valve 8 and the telescopic control valve 9 are constituted by electromagnetic proportional control valves. The hoisting control valve 8 transmits an operation signal from a hoisting operation signal generator 11 having an operation lever 10 to an elevating side signal circuit +1a and a lodging side signal circuit 11b.
It is intended to be accepted and operated through. The telescopic control valve 9 is operated by receiving a manipulation signal from a telescopic manipulation signal generator 13 having a manipulation lever 12 via an extension side signal circuit 13a and a contraction side signal circuit 13b. Reference numeral 14 denotes a winch switching valve with the same pressure on all four sides for controlling the drive of the hydraulic motor 15 for driving the winch 6. An operation signal is received from the hoisting side signal circuit 17a and the hoisting side signal circuit +7b to be operated. Now, when trying to lift a load W placed on the ground with a crane, the swivel base 2 is driven to swivel (the swivel drive device of the swivel base 2 is omitted in the figure), and the telescopic boom is driven to extend and retract in parallel with the ups and downs. At the same time, the winch 6 is driven down to position the hook H directly above the load W, the load W is hung on the hook H, and then the winch d is driven up to hoist the load W. At this time, the load acting on the telescopic boom 3 gradually increases, and as a result, the telescopic boom 3 bends and the telescopic boom 3R.

The working radius increases from - to RX shown in FIG. The work radius continues to increase until the load W is lifted off the ground. Therefore, if the load W is cut off the ground by only the hoisting operation using the winch 6, the load W will swing significantly forward at the moment before the load W is cut off. In order to prevent this, it is necessary to offset the increase in the working radius due to the deflection of the telescopic boom 3 by operating the telescopic boom 3.

As described above, the present invention offsets the increase in the working radius due to the deflection of the telescopic boom 3 that occurs when a suspended load is cut off the ground by automatically contracting the telescopic boom 3, thereby preventing load swing when cutting off the ground. It is something to do.

In FIG. 2, 18 is a boom length detector that detects the length of the telescopic boom 3, 19 is a boom elevation angle detector that detects the elevation angle of the telescopic boom 3, and 20 is a load detector that acts on the telescopic boom 3. be. In this embodiment, the load detector is constituted by a load cell interposed in the piston rod of the undulation cylinder 4.

21 receives signals from the load detector 20, the boom length detector 18, and the boom elevation angle detector 19, processes them as described later, and sends signals for driving the telescopic boom 3 to retract the telescopic boom 3. This is an arithmetic calculation unit that outputs to the device 7. 22 is an operation signal input section for operating the calculation section 2I.

The calculation unit 21 performs the following calculations. That is, the RO calculation unit 23 calculates the working radius RO when the telescopic boom 3 is not bent from the boom elevation angle signal θ from the boom elevation angle detector 19 and the boom length signal from the boom length detector 18. In, Ro=Il
Calculated based on the formula of cosθ.

On the other hand, the working radius increase amount R caused by the deflection of the telescopic boom 3 is determined as a function of the length of the telescopic boom 3, the elevation angle θ, and the load F acting on the telescopic boom 3. ΔR is calculated by the ΔR calculation unit 24 based on the formula: ΔR=fl, θ, F). When calculating 8R, the amount of increase in working radius per unit load (load acting on the telescopic boom) for each boom length and each boom elevation angle is memorized, and the boom elevation angle signal θ is calculated from these stored values. Various methods are available, such as reading a stored value corresponding to the actual boom condition based on the boom length signal 1 and calculating the value by multiplying this read value by the load signal F from the load detector 20. Available. In short, ΔR, θ, 1 and F
It is sufficient to calculate it as a function of Nα10 of .

The RO and 8R obtained as described above are added in the arithmetic calculation section 21, and the working radius (direct working radius) Rx taking deflection into consideration is calculated in the RX calculation section 25. That is, it is calculated as RX:RO+8R.

The Rx calculated in this way is
When the operation signal is manually input from 2, R is stored in the initial value storage section 26.
It is now stored as xo.

This initial value storage section 26 is stored in the RX calculation section 25 when no operation signal is input from the operation signal human power section 22.
The signal from the ←m comparator section 27, which will be described later, is directly transmitted, and when the operation signal from the operation signal input section 22 is input manually, the stored seagull is transmitted to the comparison section 27 as described above.

The comparison section 27 compares the signal from the initial value storage section 26 with R.
The signals from the x calculation unit 25 are compared, and only when the latter signal value is larger than the former signal value, the drive control device 7
A reduction drive signal is output to the reduction side Nα11 circuit +3a to the telescopic control valve 9 in. In a state where no operation signal is input from the operation signal human power unit, the human force values compared by the comparison unit 27 are the same, so the elevating drive signal is not output (the calculation unit 21 does not operate). In other words, when the load acting on the telescopic boom 3 increases after the operation signal is input and the working radius increases as a result, the comparing unit 27 reduces the telescopic boom 3 so as to offset the increase in the working radius. It generates a signal to do this.

Next, the action will be explained.

The crane is operated so that the hook H suspended from the tip of the telescopic boom 3 is positioned directly above the load W to be lifted, and the load W is hung on the hook H. At this time, the operation signal input section 22 is operated to input an operation signal to the calculation section 21 .

Then, the working radius (RXO) at that time is stored in the initial value storage section of the calculation section 21. Next, the winch 6 is operated to raise the hook H. At this time, the load F acting on the telescopic boom 3 gradually increases, and the telescopic boom 3 bends accordingly, increasing the working radius. When the actual working radius Rx becomes larger than the working radius value o stored in the initial value storage unit 26, the comparison unit 2
Even if the telescopic boom 3 bends and the working radius increases against the operator's will when the suspended load comes off, the telescopic boom 3 will contract and the working radius will increase. The increase will be automatically eliminated.

Note that the arithmetic calculation unit 21 may be configured with an analog electronic circuit, or may be configured with a digital circuit such as a microcomputer.

In the above embodiment, when the telescopic boom 3 is retracted by the signal from the comparison part 27 of the calculation part 21, the telescopic control valve 9' is moved in the telescopic boom retraction direction by the signal from the comparison part 27. However, a telescopic boom reduction drive valve is provided in parallel with the telescopic control valve 9, and this valve is connected to the comparison section 2.
Of course, you can operate it using the signal from Nα13. In this case, the telescopic boom reduction drive valve constitutes a part of the telescopic boom drive control device 7.

In the above embodiment, the operation signal input section is configured to input operation signals and control non-human power by manual operation by the crane operator, and is specifically configured with a snap switch or a push button switch. ing.

However, as an example of the development of the present invention, when the operator operates the hoisting operation lever and the telescoping operation lever of the telescopic boom, even if the operator uses the operation signal input section to input the operation signal to the arithmetic calculation device. It is preferable that the calculation device be automatically reset so that the calculation device does not operate when the telescopic boom is raised or lowered or when the telescopic boom is extended or retracted.

(Effect) In any case, the load swing prevention Hrrr when a crane with a telescoping boom of the present invention comes off a suspended load can reduce the increase in the working radius due to the deflection of the telescoping boom that occurs when a suspended load comes off the ground. Since it is possible to automatically offset Nα14, it is possible to completely eliminate load swing during ground cutting, and prevent accidents caused by load swing during ground cutting. be.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a device for preventing load handling when a crane having a telescoping boom according to the present invention unloads a load; FIG. 1 is an explanatory diagram of the crane having a telescoping boom; The figure is an explanatory diagram 1 of a device for preventing load swing at the time of unloading.

Claims (1)

[Scope of Claims] A device for preventing load swing during hoisting of a crane having a telescoping boom that can be driven to raise and lower and extend and retract, comprising: a load detector that detects a load acting on the telescoping boom; a boom length detector to detect, a boom luffing angle detector to detect the luffing angle of the telescopic boom, and receive and process signals from the load detector, the boom length detector, and the boom luffing angle detector to retract the telescopic boom; It is composed of an arithmetic calculation unit that outputs a signal for driving to a drive control device of the telescopic boom, and an operation signal input unit that operates the arithmetic calculation unit, and the arithmetic calculation unit is configured to When an operation signal is input from the signal input section, the system is configured to output a telescopic boom reduction drive signal to the telescopic boom drive control device in order to offset the increase in working radius due to deflection of the telescopic boom. A load swing prevention device for a crane having a telescoping boom when the load is unloaded.