JPH068777B2 - Hoist with wire rope damage detection function - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hoist, and more particularly to a hoist having a function of automatically detecting a damaged state of a hoisting wire rope.

[Background of the Invention]

Conventionally, as a method for detecting a damaged portion of a wire rope, for example, as shown in FIG. 6, a magnetic member 50 forming a magnetic circuit is used.
To magnetize the wire rope 51, detect the magnetic flux leaking from the damaged portion of the wire rope with the magnetic sensor 52, and process the signal into a pulse waveform that is easy to identify.
There is one that inspects the wire rope for damage.

This wire rope damage detection method has the advantage of being able to properly inspect and check the damaged portion of the wire rope, and it is used in elevator wire rope damage detection devices, but it is used for hoist wire rope inspection. There were the following problems in using it for work.

That is, when carrying a load using a hoist, pull the wire rope horizontally and diagonally to load it.
Since the unloading work may be performed, the roots of both ends of the wire rope are easily damaged, and it is necessary to perform a rope damage inspection over the entire length of the wire rope including both ends of the wire rope. , It was difficult to inspect the wire rope including both ends, and the wire rope damage detection device was incorporated in the hoist, and the rope inspection work could not always be performed after the wire rope was hoisted and unwound.

Incidentally, another device for detecting surface flaws on a rod or the like is disclosed in Japanese Patent Application Laid-Open No. 55-160838.

[Object of the Invention]

The present invention has been made to solve the above-described problems, and an object of the present invention is to be able to automatically detect damage over the entire length of a wire rope, and further to detect a wire rope damage detection device in a hoist. The purpose of the present invention is to provide a hoist with a wire rope damage detection function that can improve the safety of the hoist by simplifying the wire rope inspection work by incorporating the.

[Outline of Invention]

In order to achieve the above-mentioned object, the present invention incorporates at least one wire with insulation coating into each strand constituting a wire rope for hoist hoisting, and short-circuits one end of these wires with insulation coating to each other. A plurality of wires with insulation coating each having the other end as a detection terminal, and each of the plurality of wires with insulation coating are energized to detect disconnection of the wires with insulation coating from the presence or absence of the energized state. A wire breakage detection circuit and a voltage are applied to the insulation coating of the plurality of insulation coating wires through these insulation coating wires and other strand wires that are not insulated, and the insulation resistance of the insulation coating. A wire wear detection circuit that detects the wear state of the wire with insulation coating from the degree of change in voltage or current based on a decrease, the wire breakage detection circuit and the wire wear detection circuit, and the wire with insulation coating. Automatically on the detection terminal of A switch that connects the wires in an exchangeable manner, and the detection signals of the wire breakage detection circuit and the wire wear detection circuit are input to calculate the wire breakage rate and wear degree of the wire with insulation coating, and the wire. The hoist is provided with a wire rope damage judging means for judging the degree of damage of the rope and an alarm means for issuing an alarm when the wire rope damage judging means judges the wire rope damage degree of a specified value or more.

According to the present invention having such a configuration, the wire breakage detection circuit provided in the hoist controls the power supply to the wires with insulation coating incorporated in each strand, and thus the wire breakage rate of these wires with insulation coating is controlled. Further, the wire rope damage judging means judges the degree of damage of the wire rope from the disconnection rate, and when the rope damage degree reaches a specified value, informs the operator through the alarm means.

In addition, by automatically switching the circuit switch, the wire wear detection circuit operates, and if the wire rope wears due to deterioration over time and the insulation coating on the wire with insulation coating wears, insulation The insulation resistance of the coated wire decreases, and the degree of decrease is detected by the wire wear detection circuit. Then, the wire rope damage judging means judges the degree of damage of the wire rope based on the degree of insulation deterioration, and when the rope damage degree reaches a specified value, informs the operator via the alarm means.

Example of Invention

An embodiment of the present invention will be described with reference to FIGS.

First, prior to a detailed description of an embodiment of the present invention, an outline of an electric hoist to which the present embodiment is applied will be described with reference to FIG.

FIG. 4 is a vertical sectional view of the electric hoist,
In the figure, 1 is an electric hoist, 2 is a wire rope hoisting drum, 3 is an electric hoist frame, 4 is a load block, 5 is a wire rope, 6 and 7 are end fittings for holding the wire rope, The end fitting 6 is fitted in the cutout groove 8 provided in the drum 2, the end fitting 7 is fitted in the support 9 on the frame 3 side, and the support 9 is rotatably supported via the support pin 10. There is.

The electric hoist 1 described above incorporates a wire rope damage detection device, which is a main part of the present embodiment.
The wire rope damage detection device of this embodiment will be described with reference to FIGS.

Fig. 1 is the overall circuit diagram of the wire rope damage detection device.
FIG. 3 is a sectional view showing the internal structure of the end fittings 6, 7 of the wire rope 5 described above, and FIG. 3 is a sectional view taken along the line AA in FIG. As shown in FIG. 3, the wire rope 5 is composed of six strands 11 and a hemp core 12 mounted as an inclusion in the central portion, and each strand 11 is composed of a large number of strands 13. Has been done. Further, the central wire 14 of each strand 11 is provided with an insulating coating 15 such as enamel having solder heat resistance as shown in FIG.

The end fittings 6, 7 attached to both ends of the wire rope 5,
As shown in FIG. 2, conical hole portions 16 and 17 are axially formed inside. Then, insert the respective ends of the wire rope 5 from the smaller diameter holes of the hole portions 16 and 17, and close the wire rope 5 near the rope insertion portions of the end fittings 6 and 7.
Is tied with a tie wire 18, and each of the wire strands 13 and the center wire 14 at both ends of the wire rope 5 are unraveled to conical hole portion 1
6 and 17 to expand radially, then conical hole 1
Solder 19 is poured into 6, 17 and the strand 13 and the central strand 1
4 is fixed. Further, both ends of the center wire 14 having the insulating coating 15 are drawn out from the end fittings 6 and 7, and the end wires of the center wire 14 are covered so as not to be electrically connected to the solder 19. Are peeled off and short-circuited to each other by the short-circuiting solder 20. On the other hand, on the side of the end fitting 7, the wire ends of the respective central strands 14 that are similarly peeled off are the detection terminals 21.
It is connected to the. Each detection terminal 21 is connected to a relay contact 22 of the circuit (see FIG. 1) of the wire rope damage detection device, as will be described later, while the short-circuiting solder 20 is in an insulating state. The wire 13 is grounded by the end fittings 6 and 7.

Next, the circuit configuration of the wire rope damage detection circuit in this embodiment will be described with reference to FIG.

In FIG. 1, reference numerals 14 ₁ , 14 ₂ , 14 ₃ , ...
Reference numeral 14 _n represents each of the above-mentioned wires 14 with insulation coating, and in this circuit, for convenience of explanation, each wire 14 with insulation coating is shown.
Are set to 14 ₁ , 14 ₂ , 14 ₃ , ... 14 _n .

Reference numeral 22 is a relay contact having contacts a and b, and a microcomputer 37 described later turns on a relay coil 38.
The contacts a and b are switched by the off control. The switch 22 ′ of the relay contact 22 is connected to the detection terminals 21 side of the central strands 14 ₁ , 14 ₂ , 14 ₃ , ... 14 _n , and the b contact side of each relay contact 22 is connected via the buffer 23. It is connected to the output side of the multiplexer 24 and is connected to the input side of the multiplexer 26 via the buffer 23 '. The input side of the demultiplexer 24 is grounded 27, while the multiplexer 2
The output side of 6 is connected to the Vcc power supply via a resistor 28, and the digital input terminal 2 of the microcomputer 37 is connected.
9 is connected to this circuit, and this circuit constitutes a wire breakage detection circuit 25.

The a contact side of each relay contact 22 is connected in parallel with each other and is connected to the + pole of the reference power source 31 via the voltage dividing resistor 30.
The negative side of the reference power source 31 is grounded. Then, when the switch 22 'of each relay contact 22 is switched to the a contact side, each central wire 14 ₁ , 14 ₂ ... 14 _n is connected in parallel, and its ground resistance 32 (the insulation formed by the insulation coating 15) is connected. The voltage dividing circuit 33 is formed such that the resistance) and the voltage dividing resistor 30 described above are connected in series. When the insulation coating 15 wears due to a change with time, the ground resistance 32 is deteriorated in insulation between the central wire 14 and the grounded wire 13, so that the ground resistance 32 also decreases.

A tap 34 is provided between the contact a side of each relay contact 22 and the voltage dividing resistor 30, and the tamper 34 serves as a buffer 35.
Is connected to the analog input terminal 36 of the microcomputer 37 via.

The microcomputer 37 includes (1) the multiplexer 2
6, a circuit control function for controlling the operation of the demultiplexer 24, the relay coil 38, the alarm buzzer 43, etc. in a predetermined order, and (2) the multiplexer 26 to the digital input terminal 2
Digital signal value sent via 9, that is, high level signal (H signal) and low level signal (L signal)
The function of calculating the total of the above, calculating the wire breakage rate of the wire rope 5 from the number of L signals in the overall signal, and determining whether the wire breakage rate is a reference value or more (rope damage determination function ) And (3) the analog signal value input to the analog input terminal is A-D converted and arithmetically processed. If the analog signal input value is equal to or higher than the reference level, the wire rope 5 is normal,
In the case where the wire rope 5 is below the reference level, a function (rope damage judgment function) for judging that the degree of wear of the wire rope 5 is abnormal is built in.

The relay coil 38 is connected in series to the collector-emitter of the transistor 39, and the base of the transistor 39 is the digital output terminal 4 of the microcomputer 37.
It is connected to 0. In addition, the microcomputer 37
The digital output terminal 41 of is connected to the base of the transistor 42, and the alarm buzzer 43 is connected in series to the collector-emitter of the transistor 42.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

In the present embodiment, when the wire rope 10 has been wound up and unwound, the control function of the microcomputer 37 operates to turn off the relay coil 38 and turn off the relay contact 22.
To the b contact side. In addition, the multiplexer 26,
The demultiplexer 24 is controlled, and the central strands 14 _{1 to} 14 _{n of} the wire rope 5 are sequentially arranged in order of 14 ₁ and 14 ₂ , 14
₁ and 14 ₃ , ... 14 ₁ and 14 _n , then 14 ₂ and 14
₃ , 14 ₂ and 14 ₄ , ... 14 ₂ and 14 _n , 14 ₂ and 1
4 ₁ , then 14 ₃ and 14 ₄ ..., 14 ₃ and 14 _n , 1
4 ₃ and 14 ₁ ... Two are serially recombined, and the digital input terminal 29 of the microcomputer 37 is connected.
And the ground 27 on the input side of the demultiplexer 24 are energized. When there is no break in each of the central strands 14 _{1 to} 14 _n connected in series, the input side of the demultiplexer 24 is grounded 27, so the buffer 23 ′, the multiplexer 26, and the digital input terminal 29.
The L signal is input to the microcomputer 37 via the.

On the other hand, if there is a break in any of the two central strands 14 connected in series, the H signal is input to the microcomputer 37 via the Vcc power supply provided on the output side of the multiplexer 26.

Then, the rope damage determination function of the microcomputer 37 arithmetically processes the above-mentioned L signal and H signal, and the H signal is 5% or more of the whole, that is, two of the central strands 14 _{1 to} 14 _n connected in series. Out of all combinations, the wire breakage rate is 5
If it is determined that the value is not less than%, the alarm buzzer 43 is turned on to notify the operator. The reason why the wire breakage rate is set to 5% or more here is that the crane safety regulations require replacement if the wire rope wire breakage rate exceeds 10%, so the wire breakage rate is somewhat within that range. In consideration of the error of 1), the damage judgment standard of the wire rope 5 is set to 5%.

When the wire breakage rate of the wire rope 5 is 5% or less, the control function of the microcomputer 37 causes the relay coil 38 to operate.
Is turned on for a certain period of time to switch the relay contact 22 to the a contact side, and the central wires 14 ₁ , 14 ₂ ... 14 _n are connected in parallel. When the central strands 14 ₁ , 14 ₂ ... 14 _n are less damaged, the parallel ground resistance (insulation resistance) 32 of the central strand 14 is extremely large, and therefore the potential of the tap voltage 34 of the voltage dividing circuit 33 is increased. Is higher, microcomputer 3
An analog signal having a normal value is input to the analog input terminal 29 of 7. The analog signal is A / D converted by the microcomputer 37, and the rope damage determination function of the microcomputer 37 determines the normal state of the wire rope 5 based on the converted signal.

Further, when the degree of wear and damage of the wire rope 5 increases, the insulating coating 15 of the central wire 14 is damaged due to the friction between the wires 13, 14 of the wire rope 5, and the central wire 14 passes through this damaged portion. Part of the wire 14 is electrically connected to the grounded wire 13, the parallel ground resistance (insulation resistance) 32 of the central wires 14 _{1 to} 14 _n drops below a reference value, and eventually the tap 34 of the voltage dividing circuit 33. The potential drops, and an analog signal of an abnormal value is input to the analog input terminal 36 of the microcomputer 37. Then, the analog signal is A / D converted by the microcomputer 37, and the rope damage determination function of the microcomputer 37 determines that the wear of the wire rope 5 is at a certain level or higher based on the converted signal and controls the alarm buzzer 43 to be turned on. , Tell the worker. In addition, when the wire rope 5 is normal, the circuit state returns to the original state.

According to the present embodiment, the wire rope damage device can be automatically detected over the entire length of the wire rope every time the hoist is wound and unwound, while the wire rope damage device is still incorporated in the hoist. , It is possible to simplify the work of inspecting the wire rope that involves work at heights. In addition, since the rope can be inspected thoroughly for the rope portion near the wire rope holding end fitting, which is likely to deteriorate over time, the safety of hoisting work can be improved. Moreover, since the wire rope is replaced only by disconnecting and connecting only the detection terminal portion, the rope replacement work can be simplified.

In addition, in the above-mentioned embodiment, the insulation coating 15 is applied only to the center strand 14 of each strand to form the wire rope damage detecting member, but the insulation coating may be applied to other strands of the center strand 14. Alternatively, the wire rope damage detection member may be configured by incorporating two or more insulating coated wires in each strand.

〔The invention's effect〕

As described above, according to the present invention, the detection of wire rope damage can be left in the hoist over the entire length of the wire rope including the end fittings. Therefore, simplification of the wire rope inspection work accompanied by work at high places It is possible to improve the safety of hoisting work.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a wire rope damage detection device showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a main part of a wire rope used in the above embodiment, and FIG. 3 is a wire of FIG. FIG. 4 is a cross-sectional view of the rope taken along the line A-A, and FIG. 4 is a cross-sectional view showing the wire rope mounting portion in the electric hoist to which the above-mentioned embodiment is applied.
FIG. 5 is a flow chart showing the operation of the above embodiment, FIG.
FIG. 1 is a schematic view showing a conventional wire rope damage detection device. DESCRIPTION OF SYMBOLS 1 ... Hoist, 5 ... Wire rope, 6, 7 ... Wire rope holding end metal fittings, 11 ... Strand, 13 ... Strand element wire, 14 ... Insulation coating wire (center wire), 15 ... Insulation coating, 20 ... Short-circuiting solder, 21 ... Detecting terminal, 22 '...
Changeover switch, 22 ... Relay contact, 24 ... Energization control circuit (demultiplexer), 25 ... Strand break detection circuit, 26
... energization control circuit (multiplexer), 30 ... voltage dividing resistor,
32 ... Insulation resistance, 33 ... Voltage dividing circuit (element wire wear detection circuit), 37 ... Wire rope damage judging means (microcomputer), 43 ... Alarm means (alarm buzzer).

Claims (1)

[Claims] 1. At least one strand with insulation coating is incorporated in each strand constituting a wire rope for hoist hoisting, and one ends of these strands with insulation coating are short-circuited to each other and the other ends are used as detection terminals. A plurality of insulation-coated strands, and a wire breakage detection circuit that detects the disconnection of these insulation-coated strands from the presence or absence of the energized state by controlling the energization of each of the plurality of insulation-coated strands. , A voltage is applied to the insulating coatings of the plurality of insulating coating wires via these insulating coating wires and other strand wires that are not insulated, and a voltage based on a decrease in the insulating resistance of the insulating coating or A wire wear detection circuit that detects the wear state of the wire with insulation coating from the degree of change in current, the wire breakage detection circuit and the wire wear detection circuit to each detection terminal of the wire with insulation coating. Number of times to connect automatically The changeover switch and the detection signals of the wire breakage detection circuit and the wire wear detection circuit are input to calculate the wire breakage rate and the wire wear degree of the wire with insulation coating, and the damage degree of the wire rope. A hoist comprising: a wire rope damage judging means for judging whether the wire rope is damaged, and an alarm means for issuing an alarm when the wire rope damage judging means judges a wire rope damage degree of a specified value or more.