JP2578115Y2 - Hydraulic pump control for mobile crane - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION A mobile crane in which a hydraulic pump for generating hydraulic pressure for driving a crane mounted on a vehicle is driven by an engine for running the vehicle via a clutch which is operated by an electric signal. It is about.

[0002]

2. Description of the Related Art Referring to FIG. The mobile crane generates motive power of a vehicle traveling engine 1 by driving a hydraulic pump 4 via a clutch 3 attached to a transmission 2 of the vehicle, so as to generate driving oil pressure of the mobile crane. The clutch 3 is disconnected and operated by an electric signal output from the clutch operation switch 6, and the engine speed is controlled by the engine speed control means 5.

When the clutch operation switch 6 is selected to be in contact with the crane operation state from the running state, an electric signal is output to the clutch 3 through an electric circuit 7 for operating the clutch, and the clutch 3 is brought into the connected state.
Drives the hydraulic pump 4 via the transmission 2 and the clutch 3. The engine speed control means 5 is operated to increase the engine speed to increase the engine speed from the idling speed to the crane workable speed. When the operation lever of the crane is operated, the crane is driven by the driving oil pressure generated by the hydraulic pump 4. To increase the operation speed of the crane, the engine speed control means 5 may be further operated to increase the engine speed to increase the engine speed.

[0004] In order to complete the crane operation and bring the vehicle into a running state, the engine speed control means 5 is operated on the decreasing side of the engine speed to decrease the engine speed from the crane workable speed to the idling speed. When the clutch operation switch 6 is selected to be turned off, the output of the electric signal to the clutch 3 through the operating electric circuit 7 is cut off and the clutch 3 is turned off, so that the drive of the hydraulic pump 4 by the power of the engine 1 is cut off. It is. This state is a running state.

[0005]

In the crane operation, the clutch 3 is connected, the hydraulic pump 4 is driven by the power of the engine 1, and the engine speed control means 5 is operated to increase the engine speed. The engine speed increases from the idling speed to the crane work speed, but the crane operation lever can be operated at the idling speed or with the engine speed lower than the crane work speed. However, there was a problem of causing an engine stop.

When the engine is stopped, the operation of the crane is suddenly stopped when the operation is not intended. Therefore, the suspended load or the hook causes load swing, which is very dangerous. When the engine is further stopped, the operating lever of the crane is first returned to the neutral position to restart the engine 1, the engine speed control means 5 is returned to the idling speed position, and the clutch operation switch 6 is turned off. Thus, the clutch 3 is disengaged, the engine starter is operated, the engine 1 is restarted, and the clutch operation switch 6 is selected to connect the clutch 3 to the connected state, and the engine speed control means 5 is turned on. It is necessary to perform a complicated operation in which the engine speed must be increased from the idling speed to the crane operable speed by operating on the increasing side of the rotational speed. In addition, since the crane operable speed varies depending on the load of the crane, it is necessary to have experience to increase the engine speed from the idling speed to an appropriate crane operable speed. An object of the present invention is to provide a hydraulic pump control device for a mobile crane that does not cause an engine stop.

[0007]

Means for Solving the Problems A hydraulic pump for generating a driving oil pressure of a mobile crane mounted on a vehicle is connected via a clutch which is operated by an electric circuit for operating a clutch provided with a clutch operation switch. A mobile crane, which is configured to be driven by an engine for running a vehicle and includes engine speed control means for increasing the engine speed from an idling speed to a crane workable speed, wherein the engine speed control means It is increased but the engine speed is operated crane workable rpm
When the switch is operated and the clutch operation switch selects engagement of the clutch, the clutch is engaged so that the clutch is engaged. It was composed.

[0008]

The clutch operation switch selects the engagement of the clutch, and operates when the engine speed control means is operated to increase the engine speed to the crane operable speed. The mounted switch means is operated, an electric signal of the clutch operation switch is supplied to the clutch, and the clutch is connected.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 and FIG. Reference numerals 1 to 7 shown in FIG. 4 and described as a conventional technique are the same, and thus description thereof will be omitted and used. 8 is a switch means. The switch means 8 is provided in the electric circuit 7 for operating the clutch. When the engine speed control means 5 is operated to increase the engine speed to the crane workable speed, the operation or the engine speed is reduced. Upon detection, the operation electric circuit 7 is closed, and an electric signal for connecting the clutch 3 from the clutch operation switch 6 is transmitted to the clutch 3.
To the power supply.

[0010] When the traveling state is changed to the crane operation state, the engagement of the clutch 3 is selected by the clutch operation switch 6, and the engine speed control means 5 is operated to increase the engine speed to reduce the engine speed to the idling speed. Switch to the crane work speed.
The stage 8 detects that the engine speed has increased to the crane operable speed, closes the operating electric circuit 7, and supplies an electric signal from the clutch operation switch 6 to the clutch 3. When the clutch 3 is energized, the clutch 3 is connected, and the power of the engine 1 is transmitted to the transmission 2 and the clutch 3
The hydraulic pump 4 is driven via. When the operation lever of the crane is operated, the crane is driven by the driving oil pressure generated by the hydraulic pump 4. To increase the operation speed of the crane, the engine speed control means 5 may be further operated to increase the engine speed to increase the engine speed.

If the engine speed control means 5 is set at the idling speed when the crane is in operation, the switch means 8 opens the operation electric circuit 7 and the electric signal from the clutch operation switch 6. Is not supplied to the clutch 3, the clutch 3 is disconnected, and the engine 1 does not drive the hydraulic pump 4.

In order to complete the crane operation and bring the vehicle into a running state, the clutch 3 is disengaged by setting the engine speed control means 5 at the idling speed as in the case of waiting for operation in the crane operation state. The engine 1 does not drive the hydraulic pump 4. The selection of the engagement of the clutch 3 by the clutch operation switch 6 is released. This state is a running state.

A vehicle speed sensor 9 for detecting the vehicle speed is provided as shown in FIG. 3 so that an electric signal from the clutch operation switch 6 is not supplied to the clutch 3 when it is detected that the vehicle speed has exceeded a predetermined speed. For example, even if the driver forgets to disengage the clutch 3 when the vehicle is in the running state, the clutch 3 is disengaged and it is safe.

[0014]

[Effect of the invention] Switch means when working with a crane
Increases engine speed to crane work speed
The crane work cannot be performed unless it is done
Therefore, crane work at idling speed
Not cause engine stop. Therefore,
The operation of the engine is stopped suddenly when the operation is not intended, so that a very dangerous swing of the suspended load which occurs is not caused, and a complicated operation for restarting the engine is not required. Also, when waiting for operation in the crane working state, if the engine speed control means is set to the idling speed,
Since the clutch is disengaged and the engine does not drive the hydraulic pump, noise and fuel consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a hydraulic pump control device of a mobile crane according to the present invention.

FIG. 2 is an explanatory view of the hydraulic pump control device of the mobile crane of the present invention.

FIG. 3 is an explanatory view of a hydraulic pump control device of a mobile crane showing another embodiment of the present invention.

FIG. 4 is an explanatory diagram of a conventional hydraulic pump control device for a mobile crane.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 3 Clutch 4 Hydraulic pump 5 Engine speed control means 6 Clutch operation switch 7 Operation electric circuit 8 Switch means

Claims (1)

(57) [Scope of request for utility model registration] A hydraulic pump for generating a driving hydraulic pressure of a mobile crane mounted on a vehicle is connected to a clutch operating switch by an electric circuit for operating a clutch provided with a clutch operation switch. A mobile crane, which is configured to be driven by an engine and includes engine speed control means for increasing the engine speed from an idling speed to a crane workable speed, wherein the engine speed control means is operated and the engine is operated. Switch means for operating when the number of rotations is increased to a crane workable number of rotations is provided in an electric circuit for operating the clutch, and the switch means is operated and the clutch operation switch is operated by the clutch. The hydraulic port of the mobile crane, characterized in that the clutch is connected when the Pump control device.