JPH0637608U - Safety equipment for construction machinery - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a structure capable of automatically stopping the engine in an emergency or causing the hydraulic pump to have a minimum flow rate to stop the actuator or bring the actuator into a slight speed state when the actuator escapes. The purpose is to [Constitution] Position detecting sensors 12 and 13 for the operation lever-1 and the control valve 6 are provided, and it is judged whether or not there is an abnormality by comparing the relative positions of the operation lever-1 and the control valve 6. In the case of an abnormality, a command signal for outputting the engine speed or the hydraulic pump minimum flow rate is output, and the engine governor lever 17 or the hydraulic pump tilting device is operated in response to the command signal to stop the actuator 7. Or, it is set to a slow speed state.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a safety device for a construction machine.

[0002]

[Prior art]

 In construction machines, the operating lever and the control valve are usually connected by a wire, a rod or a hydraulic connection. This is designed to control the speed of the actuator and maximize the actuator speed by maximally displacing the operating lever, and stop the actuator by returning it to neutral. However, even if the operating lever is returned to neutral, the spool of the control valve may not return to neutral and the actuator may run away. The cause of this is the spool slack of the control valve and the spool stick of the hydraulic pilot valve. In this case, even if the operator tries to stop the actuator, it is impossible and extremely dangerous.

Conventionally, a method of manually stopping the engine when the actuator escapes has been used, but this engine stop must be processed in a very short time, and in some cases, it is quite difficult. . Especially for unfamiliar drivers, it took a long time to stop the engine, the runaway distance was long, and the risk to the driver and the people around was very high.

[0004]

[Problems to be solved by the device]

 An object of the present invention is to provide a structure capable of automatically stopping the engine in an emergency or reducing the hydraulic pump to a minimum flow rate to stop the actuator or bring it into a slight speed state when the actuator runs away.

[0005]

[Means for Solving the Problems]

 Position sensors 12 and 13 for detecting the position of the operation lever-1 and the control valve 6 are provided, and the relative position of the operation lever-1 and the control valve 6 is compared to judge whether or not there is an abnormality. In this case, a command signal for making the engine speed or the hydraulic pump minimum flow rate output is output, and the engine governor lever 17 or the hydraulic pump tilting device is actuated in response to the command signal to stop the actuator 7 or bring it to a slight speed state. I decided to.

[0006]

【Example】

 In summary, the present invention has means for detecting the position of the operating lever and means for detecting the spool position of the control valve, and compares the position of the operating lever with the position of the control valve. When the positional relationship is not preset, the engine is stopped or the engine is idle or the pump is in the minimum flow rate state.

Examples will be described below. FIG. 1 shows the operation lever-1 in a neutral state. The pressure oil discharged from the pilot pump 4 at this time flows to the pilot valve 2 through the pipe 8, but is blocked at the position a of the pilot valve 2 and does not flow any further. When the operation lever-1 is moved to the left in FIG. 1, the passage of the pilot valve 2 is switched from the position b to the position a. For this reason, the pressure oil discharged from the pilot pump 4 passes through the pipe line 8, the position a, the pipe line 10, and the c port of the control valve 6 to flow into the spray port of the control valve 6. Switch to the left side (6c position in Fig. 1). As a result, the pressure oil of the main pump 5 flows into the chamber 7c side of the actuator 7 (cylinder in the figure) and extends the cylinder.

Even if the operation lever-1 is moved to the right in the figure, the actuator 7 is contracted in the same order. The problem with this is that when the control lever 1 is operated and the control valve 6 is switched to the position 6c or 6d as described above, the operation lever-1 is set to the neutral position. When attempting to stop the actuator 7, if the pipeline 11 to the tank of the pilot valve 2 is closed due to contamination or cutting chips, the pressure oil in the pipeline 9 or the pipeline 10 will be Can't return to the tank, keep the control valve 6 in position 6c or 6d. As a result, the actuator 7 continues to be in a stretched or contracted state without stopping, and becomes a very dangerous state. Such an abnormality also occurs when the spool of the pilot valve 2 or the control valve 6 is stuck by contamination or cutting chips.

In the present invention, the position detecting sensor 12 detects the position of the operation lever 1 and the position sensor 13 detects the position of the control valve 6, and the detected position is converted into an electric signal. It is sent to the controller 3 via the signal circuits 18 and 19. The controller 3 compares the positions of the position detection sensors 12 and 13 to check whether the positional relationship between the operation lever-1 and the control valve 6 is not displaced, and if there is displacement, the motor is detected. An electric signal is given to 14 and the engine governor lever 17 of the engine 16 is pulled through the push-pull cable 15 in the fuel reducing direction. As a result, the engine 16 is stopped or brought into a low idle rotation state.

FIG. 2 is a flowchart of the above operation. The position of the operation lever-1 or the control valve 6 may be detected by using a potentiometer or the magnitude of hydraulic pressure. Further, as a method of stopping the engine or reducing the engine speed, an engine governor lever 17 is used in the example, but a fuel cut lever may be used. Further, the hydraulic pump may be in the minimum tilting state other than the engine being rotated at a low speed to bring the actuator into a very slow state.

[0011]

【effect】

 Sensors 12 and 13 for detecting the positions of the operation lever-1 and the control valve are provided respectively, and when a situation occurs in which the actuator does not stop unexpectedly, the engine is automatically stopped or rotated at a low speed. Alternatively, since the discharge amount of the hydraulic pump can be set to the minimum state and the actuator can be stopped or set to the slow speed state, safe operation can be guaranteed.

[Brief description of drawings]

FIG. 1 is a circuit diagram of the present invention.

FIG. 2 shows a flow chart of the present invention.

[Explanation of symbols] 1 Operation lever 2 Pilot valve 3 Controller 4 Pilot pump 5 Main pump 6 Control valve 7 Actuator 8, 9, 10 Pipe line 11 Pipe line 12, 13 (for position detection) sensor -14 Motor 15 Push-pull cable 16 Engine 17 Engine governor lever 18, 19 Electric signal circuit

Claims (1)

[Scope of utility model registration request] 1. An operating lever (1) and a control valve.
The sensors (12 and 13) for detecting the position of (6) are provided, and it is judged whether or not there is an abnormality by comparing the relative positions of the operation lever (1) and the control valve (6). In the case of, the engine speed or the hydraulic pump minimum flow rate is output as a command signal, and the engine governor lever (17) or the hydraulic pump tilting device is actuated in response to the command signal to operate the actuator (7).
Is a safety device for a construction machine, characterized in that it is stopped or brought into a slow speed state.