JPH0352270Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a hydraulic control device for a front loader connected to a tractor, and aims to provide a control device with a simple configuration and low cost.

[Prior art]

Conventionally, this type of hydraulic control device branches the oil path leading to the main control valve of the tractor to provide a valve exclusively for the front loader, and switches this valve by operating two levers to control the front loader. It was used to raise, lower, and rotate the bucket that was pivotally attached to the tip of the lift arm.

[Problem that the invention attempts to solve]

Although such conventional equipment is convenient in that it is equipped with a dedicated control valve, for customers who do not have to worry about using front loaders, the increased cost of this control valve makes it difficult for customers to use front loaders. However, there was a strong desire for an inexpensive hydraulic control system, even though it may be a little inconvenient.

[Means for solving problems]

This invention was proposed in view of the above-mentioned problems, and for this purpose, the following technical measures were taken.

That is, there are four positions between the main control valve 24 of the tractor 10 and the hydraulic pump 21: a rapid raise position, a neutral position, a rapid lower position, and a slow lower position.
A sub-control valve 17 for extracting external hydraulic pressure having a position is provided, and on the downstream side of this sub-control valve 17, there is a lift cylinder 4 for raising and lowering the lift arm 14 of the front loader attached to the front of the machine, and a lift A dump cylinder 5 for rotating a bucket 15 attached to the tip of the arm 14 is provided in parallel, and a switching valve 8 for switching oil passages is provided between the sub-control valve 17 and the cylinders 4 and 5. A switch 9 for operating the valve 8 is provided on the operating lever 3 of the sub-control valve 17.

〔Example〕

Hereinafter, embodiments of this invention will be described based on the drawings. First, to explain the configuration, a front loader 11 is detachably attached to the front part of the agricultural tractor 10.

14 is the lift arm of the front loader 11,
This lift arm 14 is attached to the side frame 1 attached to the aircraft body.
It is configured to be rotatable around the fulcrum 13 of 2,
Elevation is controlled by a lift cylinder 4.

A bucket 15 is rotatably attached to the tip of the lift arm 14, and the bucket 15 is rotated up and down by the dump cylinder 5.

A sub-control valve 17 for extracting external hydraulic pressure is located between a hydraulic pump 21 that is rotationally driven by the power of the engine and a main control valve 24 that controls a hydraulic lifting mechanism (not shown) installed at the rear of the tractor. is interposed.

The sub control valve 17 is the tractor 1
It is pre-equipped as standard in order to control other work equipment that is detachably connected to the 0, and has 4 positions: "rapid raise position,""neutralposition,""rapid lowering position," and "slow lowering position." Control is possible.

The sub-control valve 17 is switched by the operating lever 3, and is normally held at a neutral position as shown in FIG.

8 is a switching valve that changes the direction of flow of hydraulic oil, and is provided downstream of the sub-control valve 17;
Hydraulic oil from the sub-control valve 17 side is alternatively sent to the lift cylinder 4 or the dump cylinder 5.

This switching of the switching valve 8 is performed by pushing a switch 9 provided on the knob of the operating lever 3 of the sub-control valve 17.

That is, when this switch 9 is pressed once, the solenoid 18 is energized and the hydraulic oil is supplied to the lift cylinder 4.
When the switch 9 is pressed again, the solenoid 18 is demagnetized and the hydraulic oil flows into the dump cylinder 5 side.

In addition, the symbols 1, 2, 6, and 7 in the figure are various types of piping, 1
6 is a seat, 20 is an electric circuit for controlling the solenoid 18, 22 is a relief valve, 23 is a check valve,
25 is a tank.

In the above example, when scooping or transporting soil, manure, etc. using the front loader 11 attached to the tractor 10, the main control valve 24 is kept in the neutral position, and the operation lever of the sub-control valve 17 is 3 in the front-back direction to rotate the lift arm 14 up and down or to rotate the bucket bag 15.

For example, in FIG. 2, when the operating lever 3 is moved one step in the direction of arrow A, the hydraulic oil sent out from the hydraulic pump 21 pushes open the check valve 23, and part of it flows to the main control valve 24 side, while the rest flows into the piston rod side chamber of the dump cylinder 5, and slowly rotates the bucket 15 in the scooping direction while shortening the piston rod.

Then, when the operating lever 3 is further operated in the direction of arrow A, all the hydraulic oil that was being sent to the main control valve 24 side flows into the dump cylinder 5 side, and the bucket 15 moves in the scooping direction at a faster speed than before. can be rotated.

On the other hand, when the operating lever 3 is operated in the opposite direction of the arrow A, the piston rod of the dump cylinder 5 is pushed out and the bucket 15 is rapidly rotated in the discharge direction.

When the switch 9 provided on the operating lever 3 is pushed once during the rotation operation of the bucket 15, the changeover valve 8 is switched in the direction of arrow C, and the bucket 15 is rotated.
The rotation operation of step 5 is switched to the lifting and lowering operation of the lift arm 14.

The control speed of the lift arm 14 can be changed in the same way as the rotating operation of the bucket belt 15, and slow descent, rapid descent, and rapid ascent are possible.

As described above, the front loader hydraulic control system in this embodiment is provided with a switch 9 for switching and controlling the switching valve 8 on the operating lever 3 of the sub-control valve 17 that is standard equipment on the tractor 10, and the operating lever 3 is moved forward and backward. By simultaneously turning on and off the switch 9 while moving the lift arm 14 in the direction, the lifting and lowering operations of the lift arm 14 and the scooping and releasing operations of the bucket 15 can be selectively performed. The operation is easy because it can be performed while holding the operation lever 3.

In addition, dedicated valves for the lift cylinder 4 and dump cylinder 5, which are necessary to control the front loader 11, are unnecessary with this device, and the tractor 1
It can be configured by simply adding a switching valve 8 that switches the oil path leading to the lift cylinder 4 and dump cylinder 5, and a switch 9 that operates this switching valve 8 to the sub-control valve 17 that is standard equipment on the 0. It has a very simple structure, can be manufactured at low cost, and can be easily installed on standard tractors.

[Effect of idea]

Since this invention is configured as described above, it has the following technical effects.

That is, there are four positions between the main control valve 24 of the tractor 10 and the hydraulic pump 21: a rapid raise position, a neutral position, a rapid lower position, and a slow lower position.
A sub-control valve 17 for extracting external hydraulic pressure having a position is provided, and on the downstream side of this sub-control valve 17, there is a lift cylinder 4 for raising and lowering the lift arm 14 of the front loader attached to the front of the machine, and a lift A dump cylinder 5 for rotating a bucket 15 attached to the tip of the arm 14 is provided in parallel, and a switching valve 8 for switching oil passages is provided between the sub-control valve 17 and the cylinders 4 and 5. Since the switch 9 for operating the valve 8 is provided on the operating lever 3 of the sub-control valve 17, the sub-control valve 17 is used to separately control the elevation of the lift arm 14 and the rotation of the bucket 15. Thus, it has become possible to provide an inexpensive hydraulic control device to customers who use the front loader 11 infrequently.

[Brief explanation of the drawing]

The figures show an embodiment of this invention, with FIG. 1 being an overall side view and FIG. 2 being a hydraulic circuit diagram explaining the operation. Explanation of symbols, 3... Operation lever, 4... Lift cylinder, 5... Dump cylinder, 8... Changeover valve, 9... Switch, 10... Tractor, 1
1...Front loader, 15...Bucket, 17
...Sub control valve.

Claims (1)

[Scope of utility model registration request] Main control valve 2 of tractor 10
4 and the hydraulic pump 21, there is provided a sub-control valve 17 for extracting external hydraulic pressure, which has four positions: a rapid up position, a neutral position, a rapid down position, and a slow down position.
On the downstream side of 7, a lift cylinder 4 for raising and lowering the lift arm 14 of the front loader attached to the front of the machine and a dump cylinder 5 for rotating the bucket 15 attached to the tip of the lift arm 14 are installed in parallel. A switching valve 8 for switching oil passages is provided between the sub-control valve 17 and the cylinders 4 and 5, and a switch 9 for operating the switching valve 8 is connected to the operating lever 3 of the sub-control valve 17. A hydraulic control device for a front loader, characterized in that: