JPS62121196A - Overload preventive device for arm type crane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention is a grapple and lifting magnet.

Regarding overload prevention devices for arm-type cranes equipped with load suspension devices such as loghawks, in detail, calculate the working radius of the crane, calculate the rated total load determined from this working radius, the weight of the load suspension device, and the actual load of the arm. This invention relates to a device that prevents overload by comparing the equivalent weight applied to the tip.

[Background of the invention]

For example, a lifting magnet (
For arm-type cranes equipped with a RiffMag (hereinafter referred to as RiffMag), if the RiffMag picks up a load exceeding the rated load,
The riff mag will shake, making it difficult to work, and
In the worst case, there is a risk of the crane body falling over. Such problems also occur in arm-type cranes equipped with grapple, log hawk, etc.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an overload prevention device for an arm-type crane, which prevents a load suspension device from lifting an overload and allows safe work.

[Summary of the invention]

In order to achieve this objective, the present invention includes a boom that is attached to the crane body so that it can be raised and lowered, an arm that is rotatably attached to the tip of the boom, and a pin that is attached to the tip of the arm so that the boom can be rotated. In an arm-type crane comprising a load suspension device to be attached, a boom cylinder for raising and lowering the boom, an arm cylinder for rotating the arm, and a load suspension device cylinder for rotating the load suspension device, the tilting of the crane body Body inclination angle detector to detect the angle, boom angle detector to detect the boom elevation angle, arm angle detector to detect the relative angle between the boom and arm, load suspension device to detect the relative angle between the arm and load suspension device An angle detector, a load detector that detects the force applied to the pin at the end of the arm, and a pressure detector that measures the pressure on the bottom side and rod side of the load suspension cylinder are provided, and the signals from each of the above detectors are obtained. Equipped with a calculation device that calculates the working radius of the crane, compares the rated total load determined from the working radius, the weight of the load suspension system, and the equivalent weight of the actual load applied to the end of the arm, and outputs an overload signal. It is characterized by:

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. This embodiment describes an arm-type crane equipped with a riffmag as a load suspension device. Figure 1,
In Fig. 2, 1 is a crane body, 2 is a boom attached to the crane body 1 so that it can be raised and lowered, 3 is an arm that is rotatably attached to the tip of the boom 2, and 4 is a pin 5 attached to the tip of the arm 3. Riff mag rotatably mounted through the 6
is the boom cylinder that raises and lowers the boom 2, and 7 is the arm 3
The arm cylinder 8 rotates the riff mag 4 with the pin 5
This is a riff mag cylinder that rotates around the rod 8.
a is connected to the riff mag 4 via links 9 and 12. 10 is a pin that connects the rod 8a and the links 9 and 12; 11 is a pin that connects the link 9 to the riff mag 4; 13
is a pin that connects the link 12 to the arm 3.

The overload prevention device according to the present invention includes a main body inclination angle detector 14 that detects the inclination angle (angle to the ground) of the crane main body 1, a boom angle detector 15 that detects the up-and-down angle of the boom 2, and a relative position between the boom 2 and the arm 3. An arm angle detector 16 that detects the angle, a rifmag angle detector 17 that detects the relative angle between the arm 3 and the rifmag 4, and a load detector 18 that measures the magnitude and direction (X-Y component) of the force applied to the pin 5. , a pressure detector 19 is provided to measure the bottom side pressure and rod side pressure of the riff mag cylinder 8. Further, as shown in FIG. 3, there is provided an arithmetic device 20 that takes in signals from each of the detectors 14 to 19, performs calculations and comparisons to be described later, and outputs an overload signal.

When the computing device 20 receives the signals from each of the detectors 14 to 19, it calculates the working radius of the crane (eA in FIG. 1),
Compare the rated total load determined from the working radius with the equivalent weight applied to the tip of the arm due to the Riff Mag weight and actual load, and when it is determined that the equivalent weight approaches or exceeds the rated total load, an overload signal is activated. Output. The computing device 20 is also equipped with a display device 21 that displays the working radius, rated total load, actual load, etc. of the crane, and an alarm device 22 that issues an alarm in response to an overload signal.

Next, the operation of this embodiment will be explained.

By inputting each signal from the main body inclination angle detector 14, boom angle detector 15, arm angle detector 16, and riffmag angle detector 17 shown in FIG.
First, calculate the working radius e^ from the center of rotation of the crane body 1 to the pin 5 at the tip of the arm 3, and obtain the rated total load according to the working radius. This calculation method is detailed in the method proposed by the present applicant in Japanese Patent Application No. 17829/1982, so its explanation will be omitted here.

Next, the actual load (W) of the scrap 23 adsorbed by the riffmag 4 is calculated based on the signals from the load detector 18, the pressure detector 19, and each angle detector 14 to 17, and as shown in FIG. When the actual load (W) and the weight (W o ) of the rifmag 4 are at the pin 5 position at the tip of the arm 3, the equal unbalanced weight as seen from the rotational moment of the crane body 1 is calculated using the calculation bag [20] . The equivalent weight and the total rated load are then compared and communicated to the driver via the display device 21 and warning device 22.

The details will be explained below.

In FIG. 4, the expansion and contraction force A of the riff mag cylinder 8 is A=　I　PR-5R-PB-881 It is expressed as

Here, PR, pF3 is the rod side pressure and bottom side pressure of the rif mag cylinder 8, and SR+SR is the rif mag cylinder 8.
Rod side pressure, bottom side area.

The X-direction component F and the Y-direction component Fy of the force F (detected by the load detector 18) applied to the pin 5 are expressed by the following equations.

Fχ=Fcosy, Fy=Fsiny The X-direction component B and the Y-direction component BY with respect to the phosphorus stretching force force direction component B of the stretching force A of the rift mag cylinder 8 are expressed by the following equations, respectively.

Bz=Bcosβ, By=Bsinβ In addition, in FIGS. 4 and 5, the distance in the X-axis direction from the center of the load detector 18 to the center of gravity of the scrap 23 is e, and the distance in the X-axis direction from the center of the load detector 18 to the center of gravity of the rifmag 4 is The distance is eO1 The distance in the X-axis direction (working radius) from the center of load detector 18 to the center of rotation of crane body 1 is e^, The distance in the X-axis direction from the center of load detector 18 to the center of pin 11 is eB, Load detector 18
When the distance in the Y-axis direction from the center to the center of the pin 11 is ec, the actual load of the scrap 23 is W, and the weight of the riff mag 4 is WO, due to the balance between the moment around the load detector 18 and the force in the Y-axis direction, The following formula holds.

Wo-aO+"W' e -By-ea -Bz-ec
= O・=(1)Wo+W+Fy By"O"'(2
) (1) and (2), W and e are determined as follows.

W-By Fy Wo-(
3) e=(B)seB+f3z・ec-Wo-eo)/
(By Wo Fy) = (4) Here, Wo is known, and FY+ By+ eatB+ eC are the main body tilt angle detector 14, boom angle detector 15, arm angle detector 16, rifmag angle detector 17, and load, respectively. It can be detected by the detector 18 and the pressure detector 19.

On the other hand, riff mag 4 and scrap 2 that are added to the tip of arm 3
The equally unbalanced weight of the crane main body 1 rotation center rotating remoter 1- due to the actual load W of 3 is (Wo' + W').

Considering the moment around the center of rotation of the crane body, WO2 and W' are determined by the following formula % formula % Therefore, from formulas (5)- and (6), the equally unbalanced weight (Wo' + W
') can be determined, and as mentioned above, the rated total load according to the working radius e8 can also be determined, so the two can be compared. As a result, when it is determined that the uniform weight approaches or exceeds the rated total load, the arithmetic unit 20 outputs an overload signal, the alarm device 22 issues an alarm, and the display device 21 will be displayed.

As described above, according to this embodiment, it is possible to prevent overload on the rifmag 4, thereby preventing load swinging of the rifmag 4 or accidents of the crane body falling over.

Although the above-mentioned embodiment has been described using the rifmag 4 as a load suspension device, it is also applicable to an arm-type crane using a grapple, a log hawk, or the like. FIG. 6 shows an example in which a grapple 24 is used, and a grapple angle detector 17' is attached to a pin 5' that rotatably connects the tip of the arm 3 and the grapple 24. and a load detector 18'.

In this embodiment as well, the function as an overload prevention device is the same as in the previous embodiment, and the explanation thereof will be omitted.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to prevent overloading of the suspended load, so it is possible to prevent the load suspension device from swinging or the crane body from falling over, and it is also possible to improve the durability of the machine.

[Brief explanation of drawings]

1 to 5 show one embodiment of the present invention. Fig. 1 is an overall side view of an arm-type crane equipped with an overload prevention device according to the present invention, Fig. 2 is an enlarged side view of the boom, arm, and lift mag portion, Fig. 3 is a block diagram of the control section, and Fig. 4
The figure is a force line diagram of the forces in the rifmag section, FIG. 5 is a line diagram showing only the force lines, and FIG. 6 is a partial view of a case where a grapple is attached as another embodiment of the present invention. 1... Crane body, 2... Boom, 3... Arm, 4... Lifting magnet, 5... Pin,
6...Boom cylinder, 7...Arm cylinder, 8
...Lifting magnet cylinder, 14...
Main body inclination angle detector, 15...Boom angle detector, 1
6... Arm angle detector, 17... Lifting magnet angle detector, 18... Load detector, 19...
- Pressure detector, 20... Arithmetic device, 21... Display device, 22... Alarm device.

Claims (1)

[Claims] 1. A boom that is attached to the crane body so that it can be raised and lowered, an arm that is rotatably attached to the tip of the boom, and an arm that is rotatably attached to the tip of the arm via a pin. Detecting the inclination angle of the crane body in an arm-type crane that includes a load suspension device, a boom cylinder that raises and lowers a boom, an arm cylinder that rotates an arm, and a load suspension device cylinder that rotates the load suspension device. A main body tilt angle detector that detects the boom's elevation angle, a boom angle detector that detects the relative angle between the boom and the arm, and a load suspension system angle detector that detects the relative angle between the arm and the load suspension system. A load detector is installed to detect the force applied to the pin at the end of the arm, and a pressure detector is installed to measure the pressure on the bottom side and rod side of the load suspension cylinder. It is characterized by a calculation device that calculates the working radius, compares the rated total load determined from the working radius, the weight of the load suspension device, and the equivalent weight of the actual load applied to the end of the arm, and outputs an overload signal. Overload prevention device for arm-type cranes. 2. The overload prevention device for an arm-type crane according to claim 1, wherein the arithmetic unit is equipped with a display device that displays the working radius, rated total load, actual load, etc. of the crane. 3. The overload prevention device for an arm type crane according to claim 1, wherein the arithmetic unit is equipped with an alarm device that issues an alarm in response to the overload signal.