JP2747406B2 - Discharge port emergency shut-off device of shield machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency shut-off device for a discharge port of a shield machine, and more particularly, to a discharge port of a screw conveyor for discharging excavated earth and sand. The present invention relates to a device for performing an emergency shutoff operation in an emergency where opening and closing operations cannot be performed.

[0002]

2. Description of the Related Art FIGS. 2 and 3 show an example of a conventional shield excavator provided with a conventional discharge opening emergency cutoff device. 2 and 3, reference numeral 1 denotes a shield main body, 2 denotes a partition wall that partitions the shield main body 1 into a face side and an inboard side, and 3 denotes a cutter that is rotatably supported at a front portion of the shield main body 1 and excavates a ground. head,
4 is a cutter driving device for rotating the cutter head 3, 5 is a cutter chamber for taking in excavated earth and sand, 6 is a screw conveyor which is installed through the partition wall 2 and discharges earth and sand from the cutter chamber 5, and 7 is a screw conveyor 6 for discharging the earth and sand. Tachiguchi, 8
Reference numeral 9 denotes a gate for discharging holes, and 9 denotes a gate jack for opening and closing the gate 8.

Next, the opening and closing operation of the discharge port gate 8 will be described with reference to FIG. Normally, a check valve 13 is provided from a hydraulic source 12 in which a hydraulic pump 10 and a relief valve 11 are combined.
Pressure oil is sent to the electromagnetic switching valve 14 via the -1 and the flow of the pressure oil is switched to be supplied to the gate jack 9 by the selective excitation of the solenoids a and b from an operation panel (not shown). 8 is performed. at the same time,
The pressure oil from the hydraulic pressure source 12 flows into the accumulator 15 of the emergency shutoff hydraulic circuit through the check valve 13-2, and accumulates the pressure to a specified pressure.

Normally, the discharge port gate 8 is opened when the excavation is started and closed when the excavation is stopped. However, during the excavation, the hydraulic pump 10 stops due to a power failure or the like, and the electromagnetic switching valve 14 becomes inoperable. In some cases, the gate opening / closing operation cannot be performed normally. In that case, accumulator 1
5, the stop valve 16 at the subsequent stage is opened, and the pressure oil accumulated in the accumulator 15 is discharged to the gate jack 9 through the manual switching valve 17, thereby urgently shutting off the discharge port gate 8, and from the discharge port 7. Prevent the eruption of groundwater and earth and sand. When the discharge gate 8 catches foreign matter such as gravel at the time of emergency shut-off, the manual switching valve 17 operates the gate jack 9 in both opening and closing directions so that the gate is returned to the opening direction and the foreign matter can be removed. It is possible. The stop valve 16 is always closed in order to prevent a decrease in the accumulated pressure of the accumulator 15 due to an internal leak of the manual switching valve 17.

[0005]

Conventionally, there has been a conventional discharge port emergency shut-off device which performs an emergency shut-off operation of the discharge port gate by using the accumulated pressure of the accumulator as described above. However, since the operator does not know the accumulator accumulation state, the accumulator accumulation pressure has not reached the specified pressure required for the emergency shutoff operation of the discharge port gate for some reason. When the gate opening operation is performed by switching the electromagnetic switching valve 14, there is a possibility that the emergency shutoff function cannot be performed in an emergency such as a power failure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shield excavation that can alert a user when the accumulator pressure is insufficiently stored, thereby preventing a dangerous situation in which an emergency shutoff of a discharge port cannot be performed in an emergency. It is an object of the present invention to provide an emergency cutoff device for a machine.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, normally, pressure oil from a hydraulic source is supplied to a gate jack through an electromagnetic switching valve to open and close a gate for a discharge port of a screw conveyor. Separately from the hydraulic circuit to be operated, the pressure oil from the hydraulic source is stored in the accumulator, and the stored pressure oil is discharged to the gate jack through the manual switching valve to perform an emergency shutoff operation of the gate for the discharge port. In a discharge excavation port emergency cutoff device of a shield excavator provided with a hydraulic circuit to generate an on / off signal, an on / off signal is issued depending on whether or not the accumulated pressure of the accumulator has reached a specified pressure required for an emergency cutoff operation of a discharge port gate. A pressure switch is added to the hydraulic circuit, and in response to the output signal of the pressure switch indicating that the accumulated pressure of the accumulator has not reached the specified pressure, an alarm of the accumulated pressure abnormality is issued. A display, characterized by comprising an interlock electrical circuit that performs such that can not switching of the gate opening operation position of the electromagnetic switching valve.

[0008]

When a signal indicating that the accumulated pressure of the accumulator has not reached the specified pressure is output from the pressure switch, an alarm / display function of an electric circuit responsive thereto notifies the operator of the accumulated pressure abnormality. At the same time, the electromagnetic switching valve of the hydraulic circuit for opening and closing the gate at normal time is electrically interlocked,
Since the gate opening operation cannot be performed from the operation panel, there is no danger that the emergency opening of the discharge port cannot be shut off unlike the case where the gate opening operation is performed in a state where the accumulator pressure is insufficient.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

The hydraulic circuit of the present embodiment shown in FIG. 1A is obtained by adding a pressure switch 18 to the conventional hydraulic circuit shown in FIG. 4, and the same parts as those in FIG. , The description of which is omitted. The pressure switch 18 is provided at a position where the accumulated pressure of the accumulator 15 of the emergency shutoff hydraulic circuit can be constantly monitored, and the accumulated pressure of the accumulator 15 is adjusted to a specified pressure (gate jack 9) required for the emergency shutoff operation of the discharge port gate. An on / off signal is issued depending on whether or not the rated operating oil pressure has been reached, and the signal is sent to an operation panel (not shown) installed in the driver's seat of the shield machine.

FIG. 1B is an electric circuit diagram of the present embodiment.
The contact of the pressure switch 18 is connected to a relay 19, the normally open contact 19a of the relay 19 is connected in series to the solenoid a side of the electromagnetic switching valve 14 as an interlocking contact, and the normally closed contact 19b of the relay 19 is The display lamp 20 and the alarm buzzer 21 are connected in series as alarm display contacts. An operation switch 22 selectively excites the solenoids a and b of the electromagnetic switching valve 14.

The pressure switch 18 is connected to the accumulator 15
Is turned on when the accumulated pressure reaches a specified pressure, the relay 19 is energized by this ON signal, the normally open contact 19a is closed, and the normally closed contact 19b is opened.・ Display is released and operation switch 2
By selectively energizing the solenoids a and b by 2, the gate can be opened and closed at normal times. However, when the accumulated pressure of the accumulator 15 has not reached the specified pressure,
Since the pressure switch 18 is off, the relay 19
Is deenergized, so that the normally closed contact 19b is closed, and the operator is notified of the abnormal pressure accumulation by turning on the display lamp 20 on the operation panel surface and activating the alarm buzzer 21. at the same time,
When the normally open contact 19a of the relay 19 is opened, the electromagnetic switching valve 14 is interlocked so that the solenoid a is not excited, that is, cannot be switched to the gate opening operation position.

Although the electric circuit is formed by using a relay in the figure, a similar function can be obtained by using a sequencer instead of the relay.

[0014]

According to the present invention, a warning and display indicating that the accumulator is in an insufficiently accumulating state alerts the operator and measures necessary for maintaining the accumulator at the specified pressure. Can be taken. Furthermore, by interlocking the electromagnetic switching valve so that the gate opening operation from the operation panel cannot be performed when the accumulator pressure is insufficient, the gate for the discharge port can be opened despite the insufficient pressure accumulation. It is possible to prevent a dangerous situation in which the opening operation cannot be performed and an emergency cutoff of the discharge port cannot be performed in an emergency such as a power failure, and safety can be further improved.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing an embodiment of the present invention, wherein FIG. 1A is a hydraulic circuit diagram, and FIG.

FIG. 2 is an overall cross-sectional view of a shield machine provided with a discharge port emergency shutoff device.

FIG. 3 is an enlarged view of the vicinity of a discharge opening of FIG. 2;

FIG. 4 is a hydraulic circuit diagram showing a conventional discharge opening emergency shutoff device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shield body, 6 ... Screw conveyor, 7 ... Discharge port, 8 ... Gate for discharge port, 9 ... Gate jack, 12 ...
Hydraulic power source, 14: electromagnetic switching valve, 15: accumulator, 1
7: Manual switching valve, 18: Pressure switch, 18: Relay,
19a: Interlock contact, 19b: Alarm display contact, 20: Display lamp, 21: Alarm buzzer.

Claims (1)

(57) [Claims] 1. Normally, apart from a hydraulic circuit for supplying pressure oil from a hydraulic source to a gate jack through an electromagnetic switching valve to open and close a discharge gate of a screw conveyor,
Shield excavation provided with a hydraulic circuit that accumulates pressure oil from a hydraulic source in an accumulator and discharges the accumulated pressure oil to the gate jack through a manual switching valve to perform an emergency shutoff operation of the discharge port gate In the discharge opening emergency cutoff device of the machine, a pressure switch for generating an on / off signal is added to the hydraulic circuit depending on whether or not the accumulated pressure of the accumulator has reached a specified pressure required for the emergency cutoff operation of the discharge opening gate. In response to the output signal of the pressure switch indicating that the accumulated pressure of the accumulator has not reached the specified pressure, an alarm and display of the accumulated pressure abnormality and the switching of the electromagnetic switching valve to the gate opening operation position are disabled. Discharge port emergency shut-off device for a shield machine, comprising an electric circuit for performing a proper interlock.