JPS636269Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an automatic bottom closing device for a loading shovel.

Generally, a loading shovel is used for excavating and loading work, and is equipped with a dipper 1 that can open and close its bottom (bottom opening/closing) as shown in FIG.

The general operation pattern of this loading shovel is as follows.

Digging with day spa 1 (bottom closed), moving day spa 1 to the excavation position (swivel and raising arm 2), opening the bottom of day spa 1, closing the bottom of day spa 1, moving day spa 1 to the digging position ( (swivel and arm 2 lowering), however, in such an operation pattern, operations of and are usually performed at the same time, which is very troublesome, and in the case of an unskilled operator, even though the bottom has been closed, Instead, they continued to close the bottom, causing relief, which caused an increase in cycle time.

The present invention was developed in view of the above circumstances, and its purpose is to provide a bottom closing device for a loading shovel that automates the bottom closing without impairing the functions of the loading shovel and eliminates the bottom closing operation. do.

In addition, in general excavation and loading work using a loading shovel, it is not necessary to leave the bottom open after the bottom is opened and soil is removed, and the bottom can be opened without operator operation. There will be no inconvenience even if it is closed.

Therefore, the present invention focuses on this point and automatically closes the bottom immediately after the operator completes the bottom opening operation, thereby omitting the operator's bottom closing operation.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Figure 2 shows an embodiment of the automatic bottom closing device for a loading shovel according to the present invention.
The operation of this device will be explained with reference to the time chart shown in FIG.

When the operator performs the bottom opening operation of the day spatula 1 after the day spade 1 has been moved to the soil unloading position, the bottom opening command switch 2 is turned on during this operation period, and sends the bottom opening command signal OC (“1”) to the line a.
(See Figure 3a).

This bottom opening command signal OC is applied to the electromagnetic valve control device 3, the integrating circuit 4, and the negative circuit 5.

The solenoid valve control device 3 includes an amplifier, and when the bottom command signal OC is applied, it amplifies this signal OC and controls the solenoid 6a of the 3-position 4-connected center-closed solenoid valve 6.
Add to.

The electromagnetic valve 6 switches and controls the direction of pressure oil to the bottom cylinder 7 that drives the bottom of the dipper 1 to open and close, and is normally held in position by a spring 6c and a spring 6d.

Here, when a current is applied from the electromagnetic valve control device 3 to the solenoid 6a, the electromagnetic valve 6 is switched from one position to another.

As a result, pressurized oil is supplied from the pump 8 to the left chamber 7a of the bottom cylinder 7, so the bottom cylinder 7 moves the piston rod 7c in the direction of arrow A and opens the bottom of the dipper 11.

On the other hand, the integrator circuit 4 connects the line b to the voltage that increases over time when the bottom opening command signal OC is applied, and the voltage that decreases over time when the bottom opening command signal OC becomes "0". (see FIG. 3b).

Note that the opening speed υ _p and closing speed υ _c of the date pad 1 each take mechanically specific values, so if the opening operation is performed for t _p seconds from the opening operation time based on these eigenvalues, the closing operation will be delayed. The time t _c is calculated. That is, the time t _p and t _c have the following relationship: t _c =υ _p /υ _c ×t _p =K×t _p (K...eigenvalue).

Therefore, in the integrating circuit 4, the integration is performed so that the ratio t ₂ /t ₁ of the time t ₁ during which the voltage increases over time and the time t ₂ during which the voltage decreases over time becomes equal to the above-mentioned eigenvalue K. By setting the charging/discharging time constant of the circuit 4, the closing time corresponding to the opening time of the bottom of the dipper 1 can be determined.

The comparison circuit 9 compares the voltage applied from the integration circuit 4 with the ground voltage "0", and outputs a signal "1" when the voltage applied from the integration circuit 4 is larger than the voltage "0". That is, the comparator circuit 9 calculates the time (t ₁ +
t ₂ ), a signal “1” is output to the AND circuit 10.

Further, the NOT circuit 5 inverts the bottom opening command signal OC and outputs the inverted signal to the AND circuit 10 via the line d (see FIG. 3D).

Further, the AND circuit 10 inputs the output of the comparison circuit 9 to one input 10a and the output of the negation circuit 5 to the other input 10b, takes the AND condition of both, and uses this as the bottom close command signal CC. Add to the solenoid valve control device 3 (see Figure 3e).

The solenoid valve control device 3 receives the bottom close command signal.
When CC is applied, this signal CC is amplified and applied to the solenoid 6b of the solenoid valve 6.

Then, the solenoid valve 6 is switched from position to position, and the right chamber 7 of the bottom cylinder 7 is moved from the pump 8 to the right chamber 7 of the bottom cylinder 7.
Pressure oil is supplied to the bottom cylinder 7, and the bottom cylinder 7 moves the piston rod 7c in the direction of arrow B.
Close the bottom of.

In addition, in the above embodiment, the bottom close command signal
Although CC is set by the integrating circuit 4, the NOT circuit 5, the comparing circuit 9, and the AND circuit 10, the present invention is not limited to this. For example, when the bottom opening command signal CC falls to "0", the The bottom close command signal may be output for a predetermined period of time from this point.

As explained above, according to the present invention, once the bottom has finished opening, the bottom is automatically closed without requiring the operator to close the bottom, which reduces the burden on the operator and also reduces the increase in cycle time. It can be prevented.

[Brief explanation of the drawing]

Figure 1 is an external view of the loading shovel, Figure 2
The figure is a block circuit diagram of an automatic bottom closing device for a loading shovel according to the present invention, and FIG. 3 is a time chart showing the operation of the device shown in FIG. 2. DESCRIPTION OF SYMBOLS 1...Date switch, 2...Switch, 3...Solenoid valve control device, 4...Integrator circuit, 5...Negation circuit, 6
... Solenoid valve, 7 ... Bottom cylinder, 8 ... Pump, 9 ... Comparison circuit, 10 ... AND circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a loading shovel bottom opening/closing device that opens and closes the bottom of the day pawl of a loading shovel based on a bottom open signal and a bottom close signal, An operating switch that generates a bottom open signal to open the operating switch, and a bottom open signal that detects the change from on to off of the bottom open signal generated from this operating switch, and forms a bottom close signal that remains on for a predetermined period of time from the point of detection. a bottom close signal forming means for generating a bottom close signal; and a drive means for driving a bottom opening/closing of a day pawl of a loading shovel based on a bottom open signal output from the operation switch and a bottom close signal output from the bottom close signal forming means. A loading shovel bottom opening/closing device that automatically closes the bottom after opening the bottom. (2) The bottom close signal forming means comprises an integrating circuit that charges and discharges the bottom open signal, and a circuit that outputs the bottom close signal when the integrating circuit discharges. The bottom opening/closing device of the loading shovel described in . (3) The bottom opening/closing of the loading shovel according to claim (2) of the utility model registration, wherein the integration circuit has a ratio of each charging/discharging time constant so as to correspond to a bottom opening/closing speed ratio. Device.