JPH0216418B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for displaying the load level of a remotely controlled construction vehicle such as a radio controlled power shovel.

For radio-controlled power systems,
The operator cannot visually check what kind of load the bucket is under.

Therefore, as shown in Japanese Patent Application Laid-Open No. 53-39601,
A device has been proposed that measures the oil pressure in an extension chamber or a contraction chamber of a boom cylinder or arm cylinder that operates a bucket, calculates the oil pressure, calculates the bucket tip force, and displays the result.

However, since this device calculates the bucket tip force based on the thrust of the cylinder, pressure may not be generated in the cylinder depending on the direction of the force applied to the bucket, so it is difficult to accurately determine the load condition of the bucket. Cannot be displayed.

To solve this problem, it is necessary to measure the pressure oil of each cylinder (boom, arm, bucket cylinder) and calculate them, which makes the equipment very complicated and the calculation circuit also complicated. Therefore, it is difficult to accurately display the load status.

The present invention has been made in view of the above circumstances, and its purpose is to provide a load level display device for a remotely controlled construction vehicle that can accurately display the load state of a working machine, has a simple structure, and is inexpensive. That's true.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of a power shovel, in which an upper vehicle body 3 is provided on a lower traveling body 2 driven by a traveling motor 1, and is rotatable by a turning motor 4.
The upper body 3 is provided with a boom 6 that is vertically swung by a boom cylinder 5, the boom 6 is provided with an arm 8 that is swung vertically by an arm cylinder 7, and the arm 8 is swung vertically by a bucket cylinder 9. A bucket cart 10 is provided to be moved.

FIG. 2 is a hydraulic circuit diagram, in which the discharge passages 1 of the first and second pumps 12 and 13 driven by the engine 11 are shown.
Operation valves 2a and 13a are connected in parallel to supply pressure oil to each of the motors and cylinders.

The first and second pumps 12 and 13 are variable displacement pumps, and a servo cylinder 14 drives the swash plate 12.
b and 13b, the discharge amount is controlled to increase or decrease, and the servo cylinder 14 is moved by a spring 15 in the direction of decreasing the discharge amount.

16 is a pilot pump, and its discharge path 1
7 is connected to the first chamber 18 of the servo cylinder 14, the inlet 20 of the servo valve 19, the inlet 22 of the first control valve 21 of the summing valve A, and the inlet 24 of the second control valve 23, respectively. The operation of the servo valve 19 is controlled by the pilot pressure supplied to the pilot pressure receiving portion 19a, and increases or decreases the pressure of the pressure oil supplied to the second chamber 25 of the servo cylinder 14.

When the discharge pressure oils P ₁ and P ₂ of the first and second pumps 12 and 13 act on the first control valve 21 as pilot pressure, the second control valve 23 becomes a pressure reducing valve, and the pilot pump 16 The discharge pressure Pc of
The pressure Pt at the outlet 26 is controlled according to the discharge pressures P ₁ and P ₂ of the first and second pumps 12 and 13 as shown in the table of FIG. are supplied to the pilot pressure receiving portions 19a, respectively.

As a result, if the load on the cylinder or motor increases, the discharge pressure amount of the first and second pumps 12, 13 decreases, and if it decreases, it increases.

In other words, the outlet pressure Pt of the summing valve A has a value corresponding to the bucket load.

The discharge pressure Pt of the summing valve A is sent to a converter 30 that converts pressure into an electrical quantity, the converted electrical quantity is multiplied by a multiplier 31, and sent to a frequency converter 32, where the electrical quantity is An H signal and an L signal are alternately output to the NOR gate 33 at a corresponding period.

The output side of the NOR gate 33 is connected to the base 34a of the transistor 34.
When the signal is output, the transistor 34 is turned on and the load indicator lamp 35 is turned on.

36 and 37 are the discharge pressures of the first pumps 12 and 13
The _first and second pressure switches are turned on and off by P1 and _P2 , and the first and second pressure switches 36 and 37 are turned on and off.
When turned off, transistors 38 and 39 are turned on, and an L signal is input to the NOR gate 33. When turned on, transistors 38 and 39 are turned on, and an L signal is input to the NOR gate 33.
9 is turned off, and an H signal is input to the NOR gate 33.

The first and second pressure switches 36 and 37 are always
It is configured to be turned on, and turned off when the discharge pressures P ₁ and P ₂ of the first and second pumps reach the set pressure (the pressure at which the relief valve relieves).

Thus, when the discharge pressures P ₁ and P ₂ of the first and second pumps 12 and 13 are lower than the set pressures, H signals are inputted to the NOR gate 33 from the transistors 38 and 39, respectively.

On the other hand, from the frequency converter 32, the summing valve A
Since the H signal and the L signal are input to the Noah gate 33 at a period corresponding to the outlet pressure Pt of the bucket (in other words, a period according to the load of the bucket), the Noah gate 33
outputs an H signal and an L signal according to the period, so the transistor 34 is turned on and off in that period.
As shown in Figure 1,
A load display lamp 35 set at a location easily visible from a remote location, such as the cabin ceiling of the upper vehicle body 3, blinks in accordance with the cycle.

Therefore, the operator can visually confirm the load condition of the bucket from a remote location by the flashing frequency of the load display lamp 35 installed at a location that is easily visible from a remote location, such as the cabin ceiling.

For example, when the blinking cycle is relatively long, there is no load on the bucket and the work efficiency is low, while on the other hand, when the blinking cycle is relatively short, the bucket is overloaded and the work efficiency is low. When the flashing period is low and the blinking period is about midway, the load is appropriate and the work is being performed efficiently.

Further, when the discharge pressure of either one of the first and second pumps 12 and 13 or the first and second pumps 12 and 13 reaches the relief pressure, the transistors 38 and 39
Since the L signal is input to the NOR gate 33 from either one or both, the H signal is input from the NOR gate 33.
The signal is output, the transistor 34 turns on, and the load indicator lamp 35 continues to light up.

Therefore, since the load indicator lamp 35 is always lit, it can be confirmed that the bucket is in an overloaded state.

According to the present invention, the load display lamp blinks in accordance with the discharge pressure of the pump that supplies pressure oil to the hydraulic actuator that operates the work machine, so that the cycle of blinking of the load display lamp can be visually observed. , the operator can check the load status of the work equipment from a remote location, and can always work in the optimal load condition.

In addition, since the load status can be displayed according to the discharge pressure of the pump, the load status can always be displayed accurately, and even if the work equipment is operated by multiple hydraulic actuators, it is only necessary to provide one pressure detection means. Simple structure and low cost.

[Brief explanation of drawings]

The drawings show embodiments of the present invention.
The figure is an overall view of the power shovel, and Figure 2 is a diagrammatic configuration explanatory diagram showing its hydraulic circuit and load display circuit.
Figure 3 shows the outlet pressure of the summing valve and the first and second
It is a table showing the relationship with the discharge pressure of the pump.

Claims (1)

[Claims] 1. In a remotely controlled construction vehicle equipped with a hydraulic actuator, means for detecting a pressure corresponding to the discharge pressure of a pump that supplies pressure oil to the hydraulic actuator, and a load display lamp based on the detected pressure of the pressure detecting means. A load level display device for a remotely controlled construction vehicle, comprising means for flashing at intervals according to the detected pressure.