JP2781866B2 - Abnormality detection device in hoist operation circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation circuit of a hoist crane, and more particularly, to an abnormality detection device in a hoist operation circuit for preventing a runaway accident of a hoist crane. It is about.

[Conventional technology]

As an abnormality detection device of this type, the applicant of the present application has previously described:
Japanese Patent Application No. 58-241603 (Japanese Patent Application Laid-Open No. 60-131021)
No. 59-115225 (Japanese Patent Application Laid-Open No. 60-258821) are filed, all of which are intended to detect troubles such as welding of an electromagnetic contactor and prevent a runaway accident of a hoist crane.

[Problems to be solved by the invention]

The present invention provides an abnormality detection device in a hoist operation circuit that prevents a runaway accident of a hoist crane due to a touch in a cable connecting a control box of a hoist operation circuit and a pendant switch, which cannot be detected by the aforementioned prior art. It is intended to do so.

[Means for solving the problem]

In order to achieve the above object, the abnormality detection device in the hoist operation circuit of the present invention includes a control box and a pendant switch having a plurality of push buttons, a plurality of signal lines corresponding to the plurality of push buttons, and In an abnormality detection device for a hoist operating circuit, which is connected to a plurality of pushbuttons by a single common line, a control circuit is provided in the control box for detecting a current flowing through a common line in the control box of the hoist operating circuit. A first detector, a second detector disposed in the pendant switch for detecting a current flowing through a common line in the pendant switch, and the first detector detects a current, and 2 When the detector does not detect current, output an abnormal output signal and
And a control unit for stopping the crane.

〔Example〕

Hereinafter, an abnormality detection apparatus for a hoist operation circuit according to the present invention will be described based on an embodiment shown in the drawings.

With reference to FIG. 1, a cable 5 composed of a common line C and signal lines S1, S2,... Sx of the push button is provided between the pendant switch 1 on the driver's side and the control box 2 on the hoist body. It is electrically connected.

Both ends of the common line C, that is, the pendant switch 1
A second detector 4 for detecting a current flowing through the common line C in the pendant switch 1 is provided therein, and a first detector 4 for detecting a current flowing through the common line C in the control box 2 is provided in the control box 2. A detector 3 is provided.

FIGS. 2, 3 and 4 show a pendant switch 1
A specific example of the second detector 4 for detecting a current flowing through the common line C in the inside will be described. Of these, FIG. 2 uses a current transformer, and FIGS. 3 and 4 use a diode.

The circuit using the diodes D1, D2, and D3 shown in FIGS. 3 and 4 can be the circuit shown in FIG. 5 or FIG. 6, and the circuit shown in FIG. The terminals (~) of a commercially available single-phase bridge rectification stack shown in FIG.
(~) Can be used.

A portion 4a surrounded by a dashed line in FIGS. 2, 3, and 4 is provided in the pendant switch 1.

By arranging the second detector 4 as shown in FIG. 2, FIG. 3 or FIG. 4, only the portion 4a is disposed on the pendant switch 1, thereby causing a cross-contact in the cable of the present invention. The purpose of preventing the runaway accident of the hoist / crane can be achieved, and it is convenient to mount only a few components in the pendant switch 1. However, it is needless to say that other general current detecting means can be applied.

As the first detector 3, not only the circuit shown in FIG. 2, FIG. 3, or FIG. 4 can be applied, but also various additional parts can be built in the control box 2, so that other general Current detection means can be used.

The first detector 3 detects a current at an appropriate position in the hoist body 6 (hereinafter, referred to as “ON operation”), and the second detector 4 does not detect a current (hereinafter, “OFF operation”). ), A control unit that outputs an abnormal output signal (hereinafter, referred to as “signal S”) is provided.

The signal S output from the control unit displays an abnormality alarm, and stops the hoist / crane by activating the electromagnetic brake or stopping the traveling motor.

FIG. 8 shows a general hoist operating circuit, to which a control box 2 in FIG. 1 is additionally provided. Reference numeral 7 denotes a hoist traveling electromagnetic switch.

Next, the operation of the abnormality detection device in the hoist operation circuit will be described.

The signal of the first detector 3 that detects the current flowing through the common line C in the control box 2 is A, while the second detector 4 that detects the current flowing through the common line C within the pendant switch 1
Let B be the signal detected by.

Runaway of the hoist crane caused by contact in the cable 5 is generally caused by contact between the common line C and one of the signal lines S1, S2,. Even though the push button of the pendant switch 1 is not operated (signal B is OFF), the electromagnetic contactor MC corresponding to the signal lines S1, S2,.
1, MC2 ... MCx is closed and the hoist crane runs away (signal A is ON).
When the condition of the ON operation and the condition of the OFF operation of the signal B are satisfied, the signal S is output from the control unit.

The case where the condition that the signal A is ON and the signal B is OFF is satisfied.
In order to compare the signal B of the detector 4 with the signal A of the first detector 3, when the signal line for transmitting the signal B of the second detector 4 is cut off and the push button of the pendant switch 1 is operated , The signal S is output from the control unit.

In any case, the signal S output from the control unit displays an abnormality alarm, activates the electromagnetic brake, turns off the main electromagnetic contactor in the control box 2, and turns off the main breaker or the operation circuit. By turning off the motor and stopping the traveling motor, the hoist crane can be stopped to prevent a runaway accident of the hoist crane.

Further, by combining the invention of the earlier application relating to the detection of troubles such as welding of the electromagnetic contactor with the present invention, a runaway accident of the hoist crane can be more reliably prevented. In this case, the current detection circuit flowing through the common line C in the control box 2 can be shared with the coil current detection circuit for detecting a trouble such as welding of the electromagnetic contactor of the prior application.

〔The invention's effect〕

According to the present invention, it is possible to reliably detect a contact between a common line and a signal line in a cable connecting a control box of a hoist operation circuit and a pendant switch, thereby preventing a runaway accident of a hoist crane caused by this. It can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an abnormality detection device in a hoist operation circuit showing one embodiment of the present invention, FIGS. 2, 3 and 4 are circuit diagrams showing an embodiment of a second detector of the present invention, FIGS. 5 and 6 are circuit diagrams of the diode assembly of FIGS. 3 and 4, FIG. 7 is a circuit diagram of a single-phase rectifying stack, and FIG. 8 is a circuit diagram of a general hoist operation circuit. . DESCRIPTION OF SYMBOLS 1 ... Pendant switch, 2 ... Control box 3 ... First detector 4 ... Second detector C ... Common line S1-Sx ... Signal line

Claims (1)

(57) [Claims] 1. A control box and a pendant switch having a plurality of push buttons are connected by a plurality of signal lines corresponding to the plurality of push buttons and a common line common to the plurality of push buttons. A first detector disposed in a control box for detecting a current flowing in a common line in a control box of the hoist operation circuit, and a common line in a pendant switch. A second detector disposed in the pendant switch for detecting a current flowing through the pendant switch; and an abnormal output signal when the first detector detects the current and the second detector does not detect the current. An abnormality detection device in a hoist operation circuit, comprising: a control unit for outputting and stopping a hoist / crane.