JPH0813548A - Safety device for construction machinery - Google Patents

Abstract

PURPOSE:To inform the state to an operator in the case where a selector valve for operating two actuators selectively with one control lever, has failed to function properly. CONSTITUTION:A selector valve 28, selecting pressure oil to be outputted out of a hydraulic pilot valve 17 to a control valve 15 or 16, is interposed between two control valves 15 and 16 controlling a boom cylinder 10 and a blade cylinder 13 and this hydraulic pilot valve 17, and this selector valve 28 is selected by on-off operations of a switch 24. In addition, a pressure 29 for detecting an operating state of theselector valve 28 is connected to this valve 28. As for a relay 30, when the switch 24 is turned to ON, a coil is excited and a contact is closed, but in the case where the selector valve 28 is not selected, the pressure switch 29 is also kept in a state of being closed, whereby a buzzer 32 is connected to a power source 25 via a delay device 31, so it rings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work machine such as a hydraulic excavator, and more particularly, to a work machine safety apparatus that includes a spare actuator and shares the operation of the spare actuator with the operation lever of an existing actuator. Regarding

[0002]

2. Description of the Related Art With reference to FIGS. 7 and 8, an operation circuit of a work machine in which an operation lever of an existing actuator according to the prior art is shared for operating a spare actuator will be described. FIG. 7 is an overall view of a work machine of this type, for example, a wheel type hydraulic excavator, and FIG. 8 is a view showing its operation circuit.

In FIG. 7, a blade 1 as a spare attachment is provided on a traveling body 2 so as to be vertically movable,
On the traveling body 2, a driver's cab 3, a machine room 4 and a working device 5 are provided.
A revolving structure 6 made of, for example, is provided so as to be revolvable. The working device 5 includes a boom 7 whose one end is provided on the revolving structure 6 so as to be capable of being raised and lowered, an arm 8 whose one end is provided at the other end of which is capable of being raised and lowered, and the other end of the arm 8. And a bucket 9 rotatably provided on the side, which are respectively driven by a boom cylinder 10, an arm cylinder 11 and a bucket cylinder 12 which are existing actuators for work. The blade 1 is driven by a blade cylinder 13 as a spare actuator (not shown).

In the operator's cab 3, a working device 5, a revolving structure 6,
Operation levers and the like for operating the traveling body 2 and the blade 1 are arranged, but in the case of a hydraulic excavator, since there are many operation targets, one operation such as the boom 7 and the bucket 9, the arm 8 and the revolving structure 6 is performed. A pair of operation levers for operating the two actuators with the levers are provided on the left and right. Since there is only one operator in the space in the cab 3, it is difficult to add a new operation lever for a spare attachment such as the blade 1 due to layout and aesthetic problems in the cab 3. Therefore, conventionally, the operation of the spare attachment is commonly used by the existing operation lever. The contents will be described below with reference to FIG.

In the figure, 14 is a boom cylinder 10.
And hydraulic pump of blade cylinder 13, 15, 16
Is interposed between the hydraulic pump 14, the boom cylinder 10 and the blade cylinder 13, and the boom cylinder 1
0, a control valve for controlling the drive of the blade cylinder 13. These control valves 15 and 16 are driven by a hydraulic pilot, and are respectively in pilot chambers 15A and 1A.
5B and 16A, 16B. Reference numeral 17 is a hydraulic pilot valve, which is a pressure reducing valve 1 connected to a hydraulic pump 18.
9 and 20, and outputs the pressure of the pressure oil according to the operation amount of the operation lever 21. The hydraulic pilot valve 17 is selectively connected to the pilot chambers 15A, 15B and 16A, 16B of the control valves 15, 16 by a switching valve 22 described later. When the electromagnetic switching valve 22 is switched to the first switching position 22A by turning the switch 24 on and off, the hydraulic pilot valve 17 and the pilot chambers 15A, 1 of the control valve 15 are switched.
5B and the pilot chambers 16A and 16B of the control valve 16 are connected to the tank 23. When switched to the second switching position 22B, the hydraulic pilot valve 17 and the pilot chambers 16A and 16B of the control valve 16 are connected, and the pilot chambers 15A and 15B of the control valve 15 are connected to the tank 23.

Reference numeral 25 is a power source for the switching valve 22, and 26 is a hydraulic pump 14, control valves 15, 16 and the boom cylinder 1.
0, a relief valve that regulates the maximum pressure of the pressure oil in the drive circuit including the blade cylinder 13, 27 is the hydraulic pump 1
8, hydraulic pilot valve 17, switching valve 22, and respective pilot chambers 15A, 15B, 16 of control valves 15, 16
It is a relief valve that regulates the maximum pressure of the pressure oil in the operating circuit consisting of A and 16B.

In the prior art configured as described above, the boom operation and the blade operation by the operation lever 21 are performed as follows respectively.

During normal work of the boom 7, the switch 2 is used.
4 is turned off as shown in the figure, and the switching valve 22 is held at the first switching position 22A. For example, the operation lever 21 is
When operated in the direction, the pressure oil discharged from the hydraulic pump 18 is decompressed by the pressure reducing valve 20 of the hydraulic pilot valve 17 according to the operation amount thereof, and this pressure is transmitted via the switching valve 22 to the pilot chamber 15A of the control valve 15. Transmitted to the control valve 1
5 moves to the right position in the figure. The bottom chamber of the boom cylinder 10 is connected to the hydraulic pump 14, and the rod chamber is connected to the tank 23. As a result, the boom cylinder 10 extends and the boom 7 moves up.

When working on the blade 1, the switch 24 is turned on. As a result, the switching valve 22 is switched to the second switching position 22B, the hydraulic pilot valve 17 is connected to the pilot chambers 16A and 16B of the control valve 16, and the pilot chambers 15A and 15B of the control valve 15 are connected to the tank. 23 is connected. The control valve 15 is held in the neutral position by the spring shown. Operate lever 21 in the figure A
When operated in the direction, the pressure output from the pressure reducing valve 20 is transmitted to the pilot chamber 16A of the control valve 16 via the switching valve 22 as described above, and the control valve 16 moves to the right position in the figure. Then, the bottom side chamber of the blade cylinder 13 is connected to the hydraulic pump 14, and the rod side chamber is connected to the tank 23. As a result, the blade cylinder 13 extends and the blade 1 rises.

When the operation lever 21 is operated in the B direction in the figure, the basic movement is the same.

[0011]

By the way, in the above-mentioned prior art, when the switching valve 22 is mechanically or electrically broken, for example, the spool of the switching valve 22 sticks due to dust, or the electrical switching of the switching valve 22 is stopped. If the operator does not switch due to poor contact or the like and the operator turns on the switch 24 to operate the blade 1 and operates the operation lever 21, the boom 7 may operate.

An object of the present invention is to construct a construction machine in which one of at least two actuators is selected by a selecting means and operated by a common operating means, when an operator operates to select the other actuator. Another object of the present invention is to provide a safety device for a working machine, which informs the operator of the state of malfunction when the selecting means causes a malfunction.

[0013]

The present invention will be described with reference to FIG. 1 showing an embodiment. The present invention is based on at least two actuators 10, 1 driven by a prime mover.
3 and the safety of the construction machine provided with a selection means 28 for selecting one of the two actuators 10 and 13 to be operated, and a single operation means 17 for operating the actuator selected by the selection means 28. Applies to equipment. The invention according to claim 1 detects the operating state of the selecting means 28, and the detecting means 29.
Thus, the above-described object is achieved by providing the warning means 32 for issuing a warning when the malfunction of the selection means 28 is detected.

According to the second aspect of the present invention, a hydraulic power source 14 driven by a prime mover and at least two actuators 10, 13 driven by pressure oil from the hydraulic power source 14 are used.
Of at least two control valves 15 and 16 for controlling the drive of the actuators 10 and 13, respectively, a single operating means 17 for operating the control valves 15 and 16, and at least two control valves 15 and 16. It is applied to a safety device for a construction machine, which comprises a selection means 28 for selectively operating one of them. Further, the invention of claim 2 is provided with a detecting means 29 for detecting an operating state of the selecting means 28, and a warning means 32 for issuing a warning when the detecting means 29 detects a defective operation of the selecting means 28. This achieves the above-mentioned object.

According to a third aspect of the present invention, as shown in FIG. 2, when the detecting means 29 detects a malfunction of the selecting means 28, the actuator is made inoperable even if the operating means 17 is operated. The lock device 33 is provided.

According to a fourth aspect of the invention, as shown in FIG. 3, when the detecting means 29 detects a malfunction of the selecting means 28, the prime mover for reducing the rotation speed of the prime mover 37 to a preset rotation speed. The control means 35 and 36 are provided.

[0017]

According to the first aspect of the present invention, when the selecting means 28 malfunctions and one of the two actuators 10 and 13 operated by the single operating means 17 cannot be selected, the one of the actuators 13 and 13 cannot be selected. Selection means 28
Is detected by the detecting means 29, and the state is notified to the operator by the warning means 32. According to the second aspect of the invention, the selection means 28 has a malfunction and
When one of the control valves 16 cannot be selected, its state is detected by the detecting means 29, and the state is notified to the operator by the warning means 32. According to the third aspect of the present invention, when the detection unit 29 detects the malfunctioning state of the selection unit 28, the warning unit 32 notifies the operator of the state, and the lock unit 33 is operated to operate the operation unit 17. Even if this happens, the operation of the actuator 10 is prevented. According to the fourth aspect of the present invention, when the detecting means 29 detects a malfunctioning state of the selecting means 28, the warning means 32 notifies the operator of the state, and the prime mover control means 35, 36 also cause the rotating speed of the prime mover. Is changed to a preset low rotational speed.

Incidentally, in the section of means and action for solving the above-mentioned problems for explaining the constitution of the present invention, the drawings of the embodiments are used for the purpose of making the present invention easy to understand. It is not limited to.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIG. 1, a second embodiment is shown in FIG. 2, a third embodiment is shown in FIG. 3, a fourth embodiment is shown in FIG. An example is shown in FIGS. The same components as those in the above-described conventional technique (FIGS. 7 and 8) are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, reference numeral 28 is an electromagnetic switching valve interposed between the hydraulic pilot valve 17 and the control valves 15 and 16, and the first switching position 28A and the second switching position 28A are set by turning the switch 24 on and off. It switches to and from the switching position 28B. When the switching valve 28 is switched to the first switching position 28A, the pilot chambers 15A, 1 of the hydraulic pilot valve 17 and the control valve 15 are switched.
5B and the pilot chambers 16A and 16B of the control valve 16 are connected to the tank 23. When switched to the second switching position 28B, the hydraulic pilot valve 17 is connected to the pilot chambers 16A and 16B of the control valve 16, and the pilot chambers 15A and 15B of the control valve 15 are connected to the tank 23. The switching valve 28 is provided with a pressure detection port 28c connected to the tank 23 at the first switching position 28A and connected to the hydraulic pump 18 at the second switching position 28B. 29 is the pressure detection port 28
The pressure switch 29 is connected to the pressure switch c. The pressure switch 29 is opened when a predetermined pressure acts on the pressure detection port 28c, and closed when the pressure detection port 28c reaches the tank pressure. Reference numeral 30 denotes a relay, the relay coil of which is connected to the power supply 25 via the switch 24, and the contact of which is connected to the power supply 25 via the pressure switch 29. Three
Reference numeral 2 is a buzzer connected to the output side of the relay 30 via a delay device 31 described later.

In the first embodiment constructed as described above, the control valves 15 and 16 are used when the switch 24 is turned off to perform the boom operation and when the switch 24 is turned on to perform the blade operation. The operations of the boom cylinder 10 and the blade cylinder 13 are similar to those of the conventional art. Therefore, the following will describe how to detect the case where the switching valve 28 normally operates and the case where the switching valve 28 does not operate normally, and how to operate the buzzer 32 when the switching valve 28 malfunctions.

(1) When the switching valve 28 operates normally In a state where the switch 24 is turned off for performing work by the boom 7, the switching valve 28 is in the first switching position 28A.
The pressure detection port 28c is connected to the tank 23. Therefore, the contact of the pressure switch 29 remains closed and the contact of the relay 30 is connected to the power supply 25.
Since the switch 24 is off, the coil of the relay 30 is not excited, the power source 25 and the buzzer 32 are cut off by opening the relay contact, and the buzzer 32 does not ring.

When the switch 24 is turned on to perform the work with the blade 1, the coil of the relay 30 is excited and the contacts are closed, so that the power supply 25 and the buzzer 32 are connected via the delay device 31. However, at the same time, the switching valve 2
8 is switched to the second switching position 28B, and the pressure detection port 28c is connected to the hydraulic pump 18. Therefore, this pump pressure acts on the pressure switch 29 to open its contact, and the power supply 25 and the relay 30 are connected. The contacts are cut off. Therefore, the buzzer 32 does not ring. In the delay device 31, when the switch 24 is turned on, the switching valve 28 switches to the second switching position 28B and the pump pressure changes to the pressure switch 29.
The buzzer 32 is prevented from ringing before it acts on the.

(2) When the switching valve 28 sticks due to dust or the like and malfunctions: When the switching valve 28 sticks, the blade 1
Even if the switch 24 is turned on to operate the switch, the switching valve 28 does not operate and holds the first switching position 28A.
The pressure detection port 28c remains connected to the tank 23, and the contact of the pressure switch 29 remains closed. Therefore, the power supply 25 and the contact of the relay 30 are connected by closing the pressure switch 29. On the other hand, when the switch 24 is turned on, the coil of the relay 30 is excited and the relay contact is closed. Therefore, the power supply 25 and the buzzer 32 are connected via the delay device 31, and the buzzer 32 sounds.

Thus, if the switching valve 28 does not operate even when the switch 24 is turned on for operating the blade 1, the operator is informed that the boom 7 is in a state of moving when the operating lever 21 is operated. You can

A second embodiment will be described with reference to FIG. In addition to the configuration of the first embodiment, as shown in FIG. 2, a lock valve 33 is interposed between a hydraulic pump 18 and a hydraulic pilot valve 17, and a buzzer 32 is output by a signal output from a delay device 31. At the same time, the lock valve 33 is operated. The lock valve 33 is a valve that can switch between a position 33A that communicates the pressure oil discharged from the hydraulic pump 18 with the hydraulic pilot valve 17 and a position 33B that shuts off the hydraulic oil. When malfunction occurs, the lock valve 33 is switched to the shutoff position 33B.

In the second embodiment, when the switching valve 28 is not switched even when the switch 24 is turned on,
Similar to the first embodiment, at the same time as the buzzer 32 sounds, the lock valve 33 is switched to the cutoff position 33B, the pressure oil discharged from the hydraulic pump 18 is cut off by the lock valve 33, and the operation lever 21 is operated. However, the control valve 15 does not operate.

As a result, the operator is informed that the switching valve 28 has not been switched, and the boom 7 will not move even if the operating lever 21 is accidentally operated.

A third embodiment will be described with reference to FIG. This is, in addition to the configuration of the first embodiment, as shown in FIG. 3, an engine 37 that is a drive source of the hydraulic pumps 14 and 18, and a hydraulic cylinder for driving a governor that controls the rotation speed of the engine 37. 36, a switching valve 35 for controlling the supply and discharge of pressure oil in the hydraulic cylinder 36 by a signal output from the delay device 31, and a hydraulic power source 34 for driving the hydraulic cylinder 36.

In the third embodiment, the switch 2
When the switching valve 28 is not switched even when the switch 4 is turned on, the buzzer 32 is sounded and the switching valve 35 is switched so that the pressure oil of the hydraulic source 34 is transferred to the hydraulic cylinder 36 as in the first embodiment. Supplied, and as a result, the engine 37
The governor is driven to reduce the engine speed to a preset speed.

As a result, the operator is informed that the switching valve 28 has not been switched, and even if the operating lever 21 is accidentally operated, the discharge flow rate of the hydraulic pump 14 is suppressed by reducing the engine speed. Therefore, the boom 7 does not suddenly start moving.

A fourth embodiment will be described with reference to FIG. This is a combination of the second embodiment and the third embodiment. As shown in FIG. 4, the lock valve 33 and the switching valve 35 are simultaneously operated by a signal output from the delay device 31. I am doing it. As a result, when the switching valve 28 does not switch even if the switch 24 is turned on,
The pressure oil discharged from the hydraulic pump 18 is cut off, the control valve 15 does not operate even if the operation lever 21 is operated, and a boom malfunction is prevented. Further, since the engine speed can be lowered to a predetermined speed, for example, to an idling state, it is possible to save energy.

FIG. 5 shows a fifth embodiment, in which the relay 30 and the delay device 31 in the fourth embodiment are replaced with a microcomputer 38, and the processing flow thereof is shown in FIG. In step S1, it is determined whether the switch 24 is on or off. If the switch 24 is on, the process proceeds to step S2 and waits for a certain period of time. It plays the same role as the delay device 31. Then, in step S3, it is determined whether the pressure switch 29 is on or off, and if it is on, the process proceeds to step S4, the buzzer 32, the lock valve 33, and the switching valve 35 are turned on to ring the buzzer 32, and the pressure discharged from the hydraulic pump 18 is discharged. Cut off oil and reduce engine speed. If step S3 is off, the process returns to step S1 and continues. If the switch 24 is off in step S1, the state in step S4 is canceled in step S5. According to this embodiment, since the relay 30 and the delay device 31 are shared by the microcomputer, the number of parts can be reduced.

In the first to fifth embodiments described above, the buzzer 32 is used to notify that the switching valve 28 is not switched, but a display device such as a lamp or a monitor may be used. . Further, although the switching state of the switching valve 28 is detected by the pressure switch 29, a contact type switch such as a limit switch or a non-contact type switch such as a proximity switch may be used. In that case, The switch is attached to the end of the spool of the valve casing of the switching valve 28. In the case of a contact type switch, the spool end is brought into contact with the switch by moving the spool, and in the case of a non-contact type switch, the switching state of the switching valve is detected by the change in the magnetic field accompanying the movement of the spool. To Alternatively, a stroke sensor using magnetism or electric resistance may be attached to the spool of the switching valve 28 to detect the switching state.

Further, in the third to fifth embodiments, the hydraulic pressure source 34 is provided separately, but the hydraulic pressure source 34 is used as the hydraulic pump 1.
8 may also be used, and the engine speed is set by driving the governor by the hydraulic cylinder 36, but it may be set electrically by using a stepping motor or the like.

In the configuration of the above embodiment, the engine 3
7 is a prime mover, boom cylinder 10 and blade cylinder 13 are two actuators, switching valve 28 is a selection means, hydraulic pilot valve 17 is an operation means, pressure switch 29 is a detection means, and buzzer 32 is a warning means. The lock valve 33 constitutes a lock device, and the switching valve 35 and the hydraulic cylinder 36 constitute a prime mover control means.

The case where the boom 7 and the cylinder of the blade 1 are operated by switching them with the same operation lever has been described above. However, the present invention relates to the existing actuator, for example, the cylinder of the bucket 9 or the arm 8 and the vehicle body at the time of working. It can also be applied to the one in which the same operation lever is switched to operate the outrigger cylinder for fixing the.

[0038]

As described above, according to the present invention, when one desired actuator cannot be selected due to a malfunction of the selection means, the state is detected by the detection means and the warning means is provided. Since the operator is informed by this, it is possible to prevent the undesired actuator from erroneously operating. Furthermore, when a malfunction of the selection means is detected, the operator is informed of the state by the warning means, and even if the operation means is operated, the undesired operation of the actuator is prohibited by the lock device. Improves reliability. Furthermore, when the detection means detects a malfunction of the selection means, the prime mover control means reduces the rotation of the prime mover to a predetermined number of rotations set in advance, so that the undesired actuator operates slowly. It improves safety and also contributes to fuel saving.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a safety device for a construction machine according to the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the safety device for a construction machine according to the present invention.

FIG. 3 is a circuit diagram showing a third embodiment of the safety device for a construction machine according to the present invention.

FIG. 4 is a circuit diagram showing a fourth embodiment of the safety device for a construction machine according to the present invention.

FIG. 5 is a circuit diagram showing a fifth embodiment of the safety device for a construction machine according to the present invention.

FIG. 6 is a flowchart showing a processing procedure of a fifth embodiment.

FIG. 7 is an overall view of a wheel hydraulic excavator that is an example of a construction machine in the related art.

FIG. 8 is a circuit diagram showing a safety device for a construction machine in the related art.

[Explanation of symbols]

 10 Boom Cylinder 13 Blade Cylinder 15 Control Valve 16 Control Valve 17 Hydraulic Pilot Valve 28 Switching Valve 29 Pressure Switch 32 Buzzer 33 Lock Valve 35 Switching Valve 36 Hydraulic Cylinder 37 Engine

Claims (4)

[Claims] 1. At least two actuators driven by a prime mover, and selection means for selecting one of the two actuators to operate,
In a safety device for a construction machine, comprising a single operating means for operating the actuator selected by the selecting means,
A safety device for a construction machine, comprising: a detection unit that detects an operating state of the selection unit; and a warning unit that issues a warning when the detection unit detects an operation failure of the selection unit. 2. A hydraulic power source driven by a prime mover,
At least 2 driven by pressure oil from this hydraulic source
One actuator, at least two control valves for respectively controlling the drive of the actuators, a single operating means for operating the control valves, and one for selectively operating one of the at least two control valves. In a construction machine safety device including a selecting means, a detecting means for detecting an operating state of the selecting means, and a warning means for issuing a warning when the detecting means detects an operation failure of the selecting means are provided. A safety device for construction machinery. 3. The lock device according to claim 1, further comprising a lock device for disabling the actuator even when the operation device is operated when the detection device detects a malfunction of the selection device. The safety device for a construction machine according to claim 2. 4. A prime mover control means for reducing the number of revolutions of the prime mover to a preset number of revolutions when the detecting means detects a malfunction of the selecting means. A safety device for a construction machine according to claim 3.