JP2789375B2 - Safety equipment for construction machinery - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a safety device for operating a construction machine such as a hydraulic shovel.

2. Description of the Related Art FIG. 3 is a main part side view showing a conventional steering device of a hydraulic excavator (not shown). In the figure, 1 is a body of a hydraulic shovel, 2 is a driver's seat, 3 is a control box, 4 is an operation lever, 5 is a push-type knob, 6 is a support bracket, 7 is an arm fixed to the control box 3, 8 is a bracket, 9 is a mechanical lock mechanism, 10
Is a push-pull cable, i is a control box 3
Is a front end position that can be tilted, B is a rear end position, and 11 is a limit switch that operates when the control box 3 is tilted to the rear end position B. FIG. 4 is a view showing the structure of the mechanical lock mechanism 9. The structure will be described with reference to FIG. A pair of left-handed and right-handed coil springs 13 _L , 13 _R are tightly wound around the rod 12, and one end of each of the coil springs 13 _L , 13 _R is attached to a remote control mounting part 14 for unlocking. , the other end is attached to each groove pairing 15 _L, 15 _R. Then, when the unlocking pressing force acts on the remote control mounting portion 14 in the direction of arrow C, the coil springs 13 _L and 13 _R whose outer diameters are expanded by the spring retainer 16 are almost uniformly distributed over the entire length. Is enlarged. For this reason, the linear movement of the rod 12 is free, and the rod 12 can be adjusted to any position within the stroke range. FIG.
FIG. 4 is a partially cutaway front view as viewed from A in FIG. 3. In the figure, 17 is a pin fixed to the control box 3. The arm 7 is fixedly attached to the pin 17. FIG. 6 is a lock circuit diagram for the operation lever 4 which can disable the operation of a hydraulic actuator (such as a boom cylinder, an arm cylinder, a bucket cylinder, and a swing motor, but not shown) of the hydraulic shovel. In the figure, 11 is a limit switch that is turned on when the control box 3 is tilted to the rear end position, 18 is a key switch, 19 is a power supply, 20 is a main pump, 21 is a pilot pump, 22 is a relief valve, and 23 is Solenoid switching valves, 24 and 25 are pilot valves,
26 is a pilot switching valve for one hydraulic actuator, 27
Is an oil tank.

Next, the configuration and function of the conventional control device will be described with reference to FIGS. Control box 3
The lower part of the bracket is attached to a support bracket 6 so as to be tiltable in the front-rear direction, and a mechanical lock mechanism 9 is connected between an arm 7 fixed to the control box 3 and the bracket 8. The remote control mounting portion 14 of the mechanical lock mechanism 9 and the knob 5 are connected via a push cable 10. Then, when the knob 5 is pressed, the pressing force is
, And acts on the remote control mounting portion 14 to release the lock operation of the mechanical lock mechanism 9. When the knob 5 is kept pressed, the tilt of the control box 3 can be adjusted with a small force. The angle range of the tilt adjustment is the angle α from the rear end position a to the front end position b.
Range. When the control box 3 is tilted to the desired position angle of the driver, when the finger is released from the knob 5, the knob 5 returns to the original position, the mechanical lock mechanism 9 locks, and the control box 3 is fixed. .

On the other hand, as a lock circuit for the operation lever 4, an electromagnetic switching valve 23 is provided in an oil passage communicating the pilot pump 21 and the pilot valves 24 and 25. When the limit switch 11 is turned on when the key switch 18 is turned on, the oil passage is shut off by the electromagnetic switching valve 23. Therefore, when the driver has made the operation lever 4 operable, that is, the key switch 18 is turned on. (The engine of the excavator is rotating.) When the control box 3 is turned over to the rear end position A, the limit switch
11 turns on. Since the solenoid 28 of the electromagnetic switching valve 23 is energized, the electromagnetic switching valve 23 switches from the oil passage opening position d to the oil passage shutoff position E. The pressure oil from the pilot pump 21 is no longer sent to the pilot valves 24 and 25. Therefore, the operation of the hydraulic actuator by the operation lever 4 can be disabled.

Problems to be Solved by the Invention In a hydraulic excavator, a driver sometimes leaves a driver's seat with an engine rotated in order to perform an inspection, for example. Before leaving the seat, the control box is returned to the rear end position, and the operation of the hydraulic actuator by the operation lever is disabled (so-called operation lever lock). Thus, even when a part of the driver's body comes into contact with the operation lever when the driver leaves the seat, the actuator of the excavator does not start to move unexpectedly.

However, the above-mentioned tilting operation for returning the control box to the rear end position is very dangerous because it is difficult for the driver to sometimes return the control box to the rear end position or may forget to return it to the rear end position. Was.

The present invention solves the above-described problems, and the control box automatically returns to the rear end position when the driver leaves the seat, and the control box tilts forward when the driver sits in the driver's seat. It is intended to provide a safety device for a machine.

Means for Solving the Problems In a construction machine in which a hydraulic actuator operation is disabled in conjunction with a tilting operation of a control box, a tilting actuator for tilting the control box, and detection for detecting whether a driver is seated or unattended Means for operating the tilting actuator based on the detection result of the detection means. Further, the tilt actuator is set to a hydraulic cylinder, a hydraulic source for supplying pressure oil to the hydraulic cylinder, an electromagnetic switching valve for communicating the hydraulic source and the hydraulic cylinder to open and close an oil path, Having an electric circuit for transmitting a signal of the detection result of the detection means to the solenoid of the switching valve,
The hydraulic cylinder, which is the tilting actuator, is operated based on the detection result of the detection means. Furthermore, when the detection result of the detection means is a driver's seated state, the control box is tilted to the working position by the tilting actuator, and the detection result of the detection means is the driver's unattended state. At this time, the control box is tilted to the rear end position by the tilting actuator. Furthermore, the control box and the tilt actuator are connected via a mechanical lock mechanism, and the mechanical lock mechanism can unlock the tilt of the control box by operating means. Still further, there is provided a canceling unit for making the detection result of the detecting unit independent of the operation of the tilt actuator.

When the driver is seated in the driver's seat, the seating state is detected by the detecting means, and the control box is automatically tilted to the front working position based on the detection result. By tilting the control box to the work position, the hydraulic actuator of the construction machine can be operated in conjunction with the tilt. Conversely, when the driver leaves the driver's seat, the detection means detects the leaving state, and the control box tilts to the rear end position based on the detection result. When the control box tilts to the rear end position, the hydraulic actuator of the construction machine cannot be operated in conjunction with the tilt. In some cases, the hydraulic actuator may be operated in a state where the user is not seated depending on the work content. In this case, the operation in a state where the user is not seated can be performed by operating, for example, a switch serving as a canceling unit. That is, a so-called operation lever lock can be automatically and reliably performed.

Embodiment FIG. 1 is a circuit and configuration diagram showing a safety device according to an embodiment of the present invention. In the figure, the same reference numerals are given to components using the same components as the conventional technology.
1 'is a vehicle body of a hydraulic shovel, 2' is a driver's seat, 29 is a switch which is a detecting means for detecting whether a driver is sitting on or off the driver's seat 2 ', 30 is an electromagnetic switching valve, 31 is The solenoid of the electromagnetic switching valve 30, 32 is a power supply, 33 is a switch which is a means for canceling the detection result of the detection means, 34 is a switch 29
35, an electric circuit in which a solenoid 31 and a power supply 32 are connected in series,
Is a loose spring cylinder, which is an example of a hydraulic cylinder that is a tilting actuator, 36 is the base end of the loose spring cylinder 35, 37 is a piston rod, 38 is an oil chamber on the piston rod (37) side, and 39 is a built-in on the head side Spring, 40,4
1 is a bracket fixed to the vehicle body 1 ', 42 is a lever support, 43 is a hydraulic power source, and 27' is an oil tank. Second
The figure is a circuit and configuration diagram showing this embodiment when a driver is seated in a driver's seat 2 '. In the figure, an arrow W indicates a wearing force acting on the switch 29 by the driver.

Next, the configuration of the safety device according to one embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. A loose spring cylinder 35 is connected to the rear end of the mechanical lock mechanism 9 and is provided. A base end 36 of the loose spring cylinder 35 is engaged with a bracket 40 of the vehicle body 1 ', and an oil chamber of the loose spring cylinder 35 is provided. 38 and the hydraulic pressure source 43 are connected to the electromagnetic switching valve 30
Was connected via On the other hand, a switch 29 is provided in the driver's seat 2 'as detecting means for detecting whether the driver is seated or unattended,
The switch 29 and the solenoid 31 of the electromagnetic switching valve 30 were connected to form an electric circuit 34. When the driver is seated in the driver's seat 2 ', the control box 3 is tilted forward by supplying the pressure oil from the hydraulic pressure source 43 to the oil chamber 38 of the loose spring cylinder 35. ′ Loose spring cylinder 35
The control box 3 is tilted to the rear end position A by connecting the oil chamber 38 to the oil tank 27 '. In this embodiment, the switch 29 is provided in the driver's seat 2 'as a detecting means for detecting whether the driver is seated or unattended. However, other than the switch, a sensor (not shown) using infrared rays or another sensor is used. Means or the like may be used.

Next, the function and function of the safety device according to one embodiment of the present invention will be described. When the driver sits on the driver's seat 2 'as shown in FIG. 2 while the engine of the hydraulic excavator is rotating, the switch 29 is turned on. Since the solenoid 31 is energized, the electromagnetic switching valve 31 switches to the oil passage opening position. The pressure oil from the hydraulic pressure source 43 is supplied to the oil chamber 38 of the loose spring cylinder 35 via the oil path 45 to the oil path 44 and the oil path opening position of the electromagnetic switching valve 30. Loose spring cylinder
35 is contracted against the spring force of its built-in spring 39, so that the mechanical lock mechanism 9 moves rearward, and at the same time, the control box 3 pivots the axis of the pin 17 pivotally supporting the lower part. Automatically tilts forward. At the same time, the driver presses the knob 5 to position the control box 3 at a desired tilt angle, and then releases the finger pressing the knob 5 to fix the control box 3 at that position. Next, when the driver leaves the driver's seat 2 ', the switch 29 is turned off as shown in FIG. Since the solenoid 31 is de-energized, the electromagnetic switching valve 30 switches from the oil passage opening position to the tank communication oil passage position. Therefore, the oil chamber 38 of the loose spring cylinder 35 communicates with the oil tank 27 'via the tank communication oil path position of the electromagnetic switching valve 30. Since the oil pressure in the oil chamber 38 is reduced, the loose spring cylinder 35 is extended by the spring force of the built-in spring 39. At the same time as the mechanical lock mechanism 9 moves forward, the control box 3 automatically tilts backward about the axis of the pin 17 pivotally supporting the lower part thereof, and reaches the rear end position a. As a result, the limit switch 11 of the lock circuit for the operation lever 4 (the circuit shown in FIG. 6) is turned on, so that the operation of the hydraulic actuator by the operation lever 4 can be disabled. That is, a so-called operation lever lock can be automatically and reliably performed.

In some cases, the hydraulic excavator performs, for example, deep excavation work on the lower front side. In this case, the driver may have to operate the operation lever 4 with his / her hips behind the driver's seat in order to visually observe the lower side. In this case, the switch 33 for canceling the detection means in the electric circuit 34 is turned on in advance. Thereby, the tilt angle of the control box 3 can be fixed irrespective of whether the driver is seated or unattended during operation.

Effect of the Invention In the safety device for a construction machine according to the present invention, when the driver sits in the driver's seat, the detection state detects the seating state, and the control box automatically tilts to the forward working position based on the detection result. . By tilting the control box to the work position, the hydraulic actuator of the construction machine can be operated in conjunction with the tilt. vice versa,
When the driver leaves the driver's seat, the detector detects the leaving state, and the control box is tilted to the rear end position based on the detection result. When the control box is tilted to the rear end position, the operation of the hydraulic actuator of the construction mechanism is disabled in conjunction with the tilt. In some cases, the hydraulic actuator may be operated in a state where the user is not seated depending on the work content. In this case, the operation in a state where the user is not seated can be performed by operating, for example, a switch serving as a canceling unit.

Therefore, in the construction machine provided with the safety device according to the present invention, the operation lever can be locked automatically and reliably, so that the safety of the control device is improved.

[Brief description of the drawings]

1 and 2 are a circuit diagram and a configuration diagram showing a safety device according to an embodiment of the present invention, FIG. 3 is a side view of a main part showing a conventional control device, and FIG. 4 shows a mechanical lock mechanism. FIG. 5 is a partially cutaway front view as viewed from A in FIG. 3, and FIG. 6 is a lock circuit diagram for the operation lever. 2, 2 '... driver's seat 3 ... control box 4 ... operating lever 5 ... knob 9 ... mechanical lock mechanism 11 ... limit switch 23,30 ... electromagnetic switching valve 29,33 ... switch 34 ... Electric circuit diagram 35 ... Loose spring cylinder 38 ... Oil chamber 39 ... Built-in spring 43 ... Hydraulic source

Claims (5)

(57) [Claims] In a construction machine in which a hydraulic actuator cannot be operated in conjunction with a tilting operation of a control box, a tilting actuator for tilting the control box, and detecting means for detecting whether a driver is seated or unseated is provided. A safety device for a construction machine, wherein the tilting actuator is operated based on a detection result of the detection means. 2. A hydraulic source for supplying hydraulic oil to the hydraulic cylinder, wherein the tilting actuator is set to a hydraulic cylinder, an electromagnetic switching valve communicating the hydraulic source and the hydraulic cylinder so as to open and close an oil path, An electric circuit for transmitting a signal of the detection result of the detection means to the solenoid of the electromagnetic switching valve, whereby the hydraulic cylinder serving as the tilt actuator is operated based on the detection result of the detection means. The safety device for a construction machine according to claim 1, wherein: 3. The control box is tilted to a working position by the tilting actuator when the detection result of the detection means indicates that the driver is seated, and the detection result of the detection means indicates that the driver is unattended. 3. The safety device for a construction machine according to claim 1, wherein the control box is tilted to a rear end position by the tilt actuator when the tilt occurs. 4. The control box and the tilt actuator are connected via a mechanical lock mechanism, and the mechanical lock mechanism can unlock the tilt of the control box by operating means. The safety device for a construction machine according to any one of claims 1 to 3. 5. A safety device for a construction mechanism according to claim 1, further comprising canceling means for making the detection result of said detecting means independent of the operation of said tilting actuator.