JPS6357358B2 - - Google Patents

Description

Detailed Description of the Invention The present invention is capable of quickly detecting falling cargo when transporting molten metal in a melting furnace, transporting dangerous cargo using a crane, etc., and preventing accidents caused by dangerous substances. This invention relates to a fall detection device for a transported object that has an abnormality diagnosis function and is applicable to cargo handling machines such as cranes, which need to be stopped in order to prevent this from happening.

Generally, a device is not provided to detect the fall of a suspended load while it is being lifted or transported by a crane.

For example, a case will be described in which molten metal is transported from a melting furnace to a mold by a crane. First, the ladle is brought to the molten metal outlet of the melting furnace using a crane or a mobile cart and placed in a fixed position. Next, the molten metal outlet of the melting furnace is opened and the molten metal is transferred to the ladle. Once the molten metal is transferred to a ladle, it is lifted up by a crane and transported to a predetermined mold position according to instructions and guidance from the operator. Cranes are operated either on the ground using operation buttons or from the operator's cab, both of which are performed visually.

When lifting and transporting molten metal in a ladle, if a falling load that requires an emergency stop occurs while the crane is moving, the ground guide will send a signal to the crane operator to stop the crane, or The crane operator can either stop the crane visually, but there is a lag in terms of timing and this is not a safe method. In particular, a timing delay caused by a falling accident while the crane was in motion could lead to a major accident.

This invention was made in order to solve the above-mentioned problems, and to promptly detect the fall when a suspended load accident occurs, to redundant circuits, and to automatically stop the crane, etc. , a load detection unit that detects the suspended load of the crane and generates two systems of suspended load signals, and compares the set load with two systems of monitoring area signals that output monitoring signals when the crane operates within the set monitoring area. Two signals from two systems of comparator 1 that detect the suspended load state and two signals from two systems of comparator 2 that detect the state of no suspended load are input, and one of each system is abnormal. an abnormality diagnosis circuit that outputs an abnormality diagnosis signal when the abnormality diagnosis circuit operates, a crane operation command signal that outputs a crane stop command based on the signal of the abnormality diagnosis circuit, and a crane operation command signal that indicates the operating state of the crane, a monitoring area signal, and a comparator 1. The abnormality diagnosis function is characterized by being equipped with a two-system fall detection circuit that inputs the signal from the comparator 2 and the signal from the comparator 2 to detect the fall of a suspended load, and outputs a fall detection output and a crane stop command output. This invention presents a fall detection device for conveyed objects.

When lifting the suspended load and starting the lifting operation, the suspended load is detected by a load cell, and if the load is equal to or greater than a preset load value, it is stored that the suspended load has been lifted. If the load value rapidly decreases during the upward and downward movements in this state, it is determined that the suspended load has fallen, and a fall output is output. In order to avoid the same phenomenon in which the load value decreases as described above when lowering a suspended load normally, the height at which the suspended load is lowered is monitored, and the decrease in load value during this elevation is normal. It is determined that this is the case and an interlock is set to prevent falling output. In addition, the circuit is duplicated and one series is A series,
The other system is the B system, and each circuit and power supply system are independent, so that even if one system malfunctions due to circuit abnormality, the other system can operate normally. Furthermore, during normal operation, the operations of the A and B systems are the same, but if the operations of the A and B systems do not match, an abnormality diagnosis circuit is activated to determine that the system is abnormal and has logic that immediately stops the crane, etc. It is a device.

Next, a fall detection device for a conveyed object having an abnormality diagnosis function according to the present invention will be described.

FIG. 1 shows a block diagram of the entire device. Here, the load cell 1 attached to the upper part of the crane hoist, which is the hanging load detection part, is a double bridge type.
It is assumed that the system and B system can each output (load detection) independently. (In the figure, they are shown as A/OUT and B/OUT, respectively.) Since the A system and the B system are the same, the A system will be explained below. The output of the load cell 1 is input to a commercially available signal conditioner (DC amplifier) 2A and amplified to a required voltage level.
(2A1 indicates a zero point adjustment, and 2A2 indicates a sensitivity adjustment resistor.) This signal increases the output impedance by the buffer amplifier 3A, making it possible to output voltage at multiple points. The output of this buffer amplifier 3A is input to comparator 1 of 4A1 and comparator 2 of 4A2. Comparator 1 of 4A1 compares the voltage with setting 1 of 4A10, and outputs an ON signal if the voltage is higher than the set voltage. Comparator 2 of 4A2 compares the voltage with setting 2 of 4A20, and outputs an ON signal if the voltage is lower than the set voltage. Incidentally, setting 1 of 4A10 is set as a value obtained by subtracting a slight margin from the hanging load value, and setting 2 of 4A20 is set as a value with a slight margin added to the load value in the state of "no" hanging load.

The fall detection circuit 5A is the comparator 1 of 4A1,
This is a logic circuit based on the signal of comparator 2 of 4A2 and the control input signal 6A (a signal that defines the monitoring height and excludes the area where a normal hanging load is lowered and separated from being monitored), and is the logic circuit shown in Fig. 2. A crane stop command 18 and a fall detection output 19 are output. Reference numeral 7 denotes an abnormality diagnosis circuit, which outputs a crane stop command when the circuit operates abnormally, as will be described later. The B system, which has the same configuration as the A system consisting of these, is connected to load cell 1, and each function is indicated by the same number with the A system number changed from "A" to "B", and the two systems as a whole are It is configured. Reference numeral 7 denotes an abnormality detection circuit, the details of which will be explained in FIG.

FIG. 2 is a block diagram showing in detail the fall detection circuits 5A and 5B in the block diagram of FIG.
(Since 5A and 5B are the same, they will be described as A-series circuits.) Both the crane operation command 10A (10B is not shown in this specification for convenience of explanation) and the monitoring area signal 6A are "H" ( high level)
state, and the output of comparator 1 of 4A1 (preset hanging load setting value) is “H”
In this state, the output of the AND circuit 11 becomes "H", the output of the AND circuit 12 becomes "H", and the flip-flop
4 (memory element). Normally, the crane performs lifting and lowering operations in this state. Further, as a condition for the crane to operate, it is necessary that the abnormality diagnosis signal 60 is in the "L" (low level) state. This abnormality diagnosis signal 60 is an output of the abnormality diagnosis circuit 7 whose details are shown in FIG. 3, and will be explained later.

Here, if a suspended load accident occurs, 4A2
Comparator 2 (outputs ON when the load value is lower than the preset "no" load) is activated and 4
The output of comparator 2 of A2 becomes "H". At this time, the AND circuit 16 outputs a fall detection output 1 based on the output of the inverter 15 and the output of the flip-flop 14.
Outputs 9. At the same time, the output of AND circuit 16 is OR
Since the signal is input to the circuit 17, the OR circuit 17 outputs a crane stop command output 18. Incidentally, the condition for resetting the flip-flop 14 is when the crane is out of the monitoring area and the monitoring area signal 11 becomes "L". Here, the area outside the monitoring area means the position where the suspended load is normally placed on the bottom (separated), and has the above-mentioned interlock function. In this manner, when a fall accident occurs, a fall detection signal is immediately output and the crane operation can be stopped.

Next, FIG. 3 shows a basic logic diagram of the abnormality diagnosis circuit 7. The basic concept of abnormality diagnosis is A system and B system.
Input signals and circuit signals duplicated in the system, namely monitoring area signals 6A and 6B and comparator 1
The two systems 4A1 and 4B1 of the comparator 2 and 4A2 and 4B2 of the comparator 2 normally perform the same operation.

For example, under normal crane operating conditions, monitoring area signals 6A and 6B are "H", and comparator 1's 4A
1 and 4B1 are "H", and 4A2 and 4B2 of comparator 2 are "L", and these signals are connected to inverters 20 to 25, AND circuits 30 to 37, and OR circuits 40, 41, and 42. The output of the OR circuit 50 becomes "L" through the circuit, and the abnormality diagnosis signal 60 is in the "L" state. If only one of each of the two systems operates and the other becomes inoperative due to some kind of failure, it is determined that the system is unreasonable, and this circuit is set to "H" by the OR circuit 50.
Outputs the signal and turns on the abnormality diagnosis output 60.
When the abnormality diagnosis output 60 turns ON, as shown in Fig. 2, the OR circuit 17 of the fall detection circuit outputs the crane stop output 18 to stop the crane, and at the same time outputs an erroneous suspended load drop signal due to a circuit failure. prevent it from happening.

It goes without saying that this device described above can be used in all fields, including transporting molten metal in melting furnaces, transporting fuel in nuclear plants, and transporting and transporting other potentially dangerous materials and products. Nor.

According to the falling object detection device having an abnormality diagnosis function of the present invention as described above, it is possible to reliably detect falling accidents during the transportation of dangerous objects such as melting furnaces, and prevent major accidents such as explosions and fires caused by dangerous objects. In addition, the abnormality diagnosis circuit can detect system abnormalities and immediately stop the operation of the device, thereby preventing accidents in advance.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the overall configuration of a fall detection device for conveyed objects having an abnormality diagnosis function according to the present invention, Fig. 2 is a circuit diagram showing the logic of the fall detection circuit in Fig. 1, and Fig. 3 is a A circuit diagram showing the logic of the abnormality diagnosis circuit in FIG. 1 is shown. 4A1, 4B1: Comparator 1, 4A2, 4
B2: Comparator 2, 5A, 5B: Fall detection circuit, 6A, 6B: Monitoring area signal, 7: Abnormality diagnosis circuit, 10A, 10B: Crane operation command, 18:
Crane stop command, 19: Fall detection output, 60:
Abnormal diagnostic signal.

Claims (1)

[Claims] 1 A load detection unit that detects the suspended load of the crane and generates two systems of suspended load signals, the crane operation command signal is "H", the monitoring area signal that outputs a signal in the normal crane operating state is "H", and the suspended load is Comparator 1, which outputs a signal when present, is “H”,
When a suspended load falls while the crane is operating, and the signal of comparator 2 becomes "H", a fall detection signal is output, and the crane is stopped by the OR signal of this fall detection signal and the abnormality diagnosis signal that is generated when the circuit is abnormal. There are two fall detection circuits that output signals, and when the crane is in operation, the monitoring area signals of the two systems are "H", the signals of the comparator 1 of the two systems are "H", and the signals of the comparator 2 of the two systems are "L". ”, and the abnormality diagnosis signal is in the “L” state, and in this state, for some reason, at least one of these two systems of monitoring area signals, comparator 1, and comparator 2, outputs an opposite signal. A fall detection device for a conveyed object having an abnormality diagnosis function, comprising: an abnormality diagnosis circuit that sets an abnormality diagnosis signal to "H" when an abnormality diagnosis signal is generated.