JPS5940564Y2 - Agricultural front loader - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an agricultural front loader, in which the operation of the lift arm can be switched between single action and double action by adding a simple mechanism.

Conventionally, there were separate single-acting and double-acting operating types for the lift arms of agricultural front loaders, but these have advantages and disadvantages in working functions, and depending on the working conditions, It was an inconvenience.

This idea is an improvement on the above-mentioned conventional drawbacks.The lift cylinder that moves the lift arm up and down uses hydraulic pressure only when lifting it up, and when it goes down, it is lowered only by the lift arm's own weight. The purpose is to provide a single-acting hydraulic lift cylinder.

The configuration of this invention will be explained below according to an embodiment shown in the drawings.

In FIG. 1, reference numeral 1 denotes a lift arm whose rear end is attached to a tractor 2.

3 is a tip working device, 4 is a lift cylinder, and 5 is a dump cylinder.

FIG. 2 shows the neutral state of the hydraulic circuit according to the present invention. Reference numeral 6 indicates a dump cylinder directional control valve, and 7 indicates a lift cylinder directional control valve. , 7 are both in a neutral state.

The dump cylinder directional control valve 6 is a 3-position, 6-port manual switching valve with three switching positions: scoop, neutral, and dump, and has three ports on the cylinder side: a, b,
It has three ports d, e, and f on the pump side.

The lift cylinder directional control valve 7 is a 3-position, 6-port manual switching valve with three switching positions: up, neutral, and down, and has three ports g, h, and i on the cylinder side, and one on the pump side. It has A on three ports, j,.

8 is an oil passage 17 from the piston front chamber of the lift cylinder 4
This is a stop valve installed in the middle of the oil passage 13.
It is connected to the.

9 is a hydraulic pump, and 10 is a tank.

3 on the cylinder side of the dump cylinder directional control valve 6
Of the three ports a, b, and c, port b
, c is the oil passage 11 in the front and rear chambers of the piston of the dump cylinder 5.
．． 12.

The port a is connected to the oil passage 13 of the tank 10, and the port f is also connected to the oil passage 13 of the tank 1 through an oil passage 13'.

Pump side port of dump cylinder directional control valve 6) d,
Port d of e and f is connected to port g on the cylinder side of the lift cylinder directional control valve 7, and the remaining port e of the dump cylinder directional control valve 6 is connected via a check valve 14 in the middle. It is also connected.

Furthermore, from the middle, the port on the pump side of the lift cylinder directional control valve 7) 4? An oil passage 15 is connected thereto, and a check valve 16 is installed in the middle of the oil passage 15.

Port g on the cylinder side of the lift cylinder directional control valve 7
, h, and i, the remaining ports h and i are connected to the oil passage 17 in the front and rear piston chambers of the lift cylinder 4. It is connected to 18.

These two oil passages 17. 18, the middle of the oil passage 17 on the piston front chamber side is connected to the oil passage 13 of the tank 16 via the stop valve 8 of the present invention.

Port j on the pump side of the lift cylinder directional control valve 7,
Of k and ff, port j is connected to hydraulic pump 9, and port k is connected via check valve 19 on the way.
It is also connected.

The above is the tank bottom of the agricultural front loader according to the present invention, and the operation procedure thereof will be explained below.

[When the stop valve 8 is closed] (a) In the case of independent operation Figure 3a shows the state in which the lift cylinder directional control valve 7 is switched to the raised position, and at this time the dump cylinder directional control valve 6 is in the neutral position. The position is mine.

That is, in this state, the pressure oil from the pump 9 pushes open the check valve 18 and is supplied to the piston rear chamber of the lift cylinder 4 through the oil passage 18 from the port i.

Then, lift cylinder 4 extends and lift arm 1
to rise.

Then, the oil in the front chamber of the piston of the lift cylinder 4 passes through the oil passage 17 to port h, passes through the oil passage 15 from h to the oil passage 15, pushes open the check valve 15, and reaches the port d of the dump cylinder directional control valve 6.

a, returns to the tank 10 via the oil path 13.

FIG. 3 shows a state in which the lift cylinder directional control valve 7 is switched to the lowered position, and the dump cylinder directional control valve 6 is in the neutral position.

That is, in this state, the pressure oil from the hydraulic pump 9 pushes open the check valve 19 and flows into the port from h to the oil path 17.
It is supplied to the piston front chamber of the lift cylinder 4 through the piston front chamber.

Then, the oil in the rear chamber of the piston of lift cylinder 4 flows through oil passage 1.
Port i of the cylinder directional control valve 7 through 8 to the rift 1
, p, the check valve 16 of the oil passage 15 is pushed open, and the oil is returned to the tank 10 via the oil passage 13 from ports d and a of the dump cylinder directional control valve 6.

Therefore, the lift cylinder 4 is retracted and the lift arm 1 is lowered.

In short, when the dump cylinder directional control valve 6 is set to neutral and the lift cylinder directional control valve 7 is switched to ascending or descending, the lift cylinder 4 operates independently and the lift arm 1 moves up and down independently. I can do it.

FIG. 4a shows a state in which the dump cylinder directional control valve 6 is switched to the rake position and the lift cylinder directional control valve 7 is switched to the neutral position.

That is, in this state, pressure oil from the hydraulic pump 9 pushes open the check valve 14 from port j5g, passes through the oil passage 12 from ports e and c of the dump cylinder directional control valve 6, and flows into the dump cylinder 5. The oil in the piston front chamber and the piston rear chamber of the dump cylinder 5 is supplied from the oil passage 11 to the port 1-b of the dump cylinder directional control valve 6.

f, and is returned to the tank 10 via oil passages 13' and 13.

Therefore, the dump cylinder 5 is retracted, causing the tip working device 3 to perform a scooping operation.

FIG. 4 shows a state in which the lift cylinder directional control valve 7 is in the neutral position and the dump cylinder directional control valve 6 is switched to the dump position.

That is, pressure oil from the hydraulic pump 9 pushes open the check valve 14 from port j9g, and is supplied to the piston rear chamber of the dump cylinder 5 through the oil passage 11 from ports e and b of the dump cylinder directional control valve 6. The oil in the piston front chamber of the dump cylinder 5 is returned to the tank 10 through the oil passage 12 from the ports c and f of the dump cylinder directional control valve 6 through the oil passages 13' and 13.

Therefore, the dump cylinder 5 is extended, and the tip working machine 3
perform a dump operation.

In short, when the lift cylinder directional control valve 7 is set to neutral and the dump cylinder directional control valve 6 is switched to the rake or dump position, the dump cylinder 6 independently expands and contracts, moving the work equipment 3 in the vertical direction. It is rotated to handle or discharge work objects such as earth and sand.

(b) Simultaneous operation FIG. 5a shows a state in which the lift cylinder directional control valve 7 is switched to the raised position and the dump cylinder directional control valve 6 is switched to the rake position.

That is, the pressure oil from the hydraulic pump 9 pushes open the check valve 19 and enters the port through the oil passage 18 from i to the lift cylinder 4.
The oil in the piston front chamber of the lift cylinder 4 is supplied to the piston rear chamber of the lift cylinder 4 through the oil passage 17 to the ports h, β,
The oil is supplied from the ports 1-e, e of the dump cylinder directional control valve 6 through the oil path 15 to the piston front chamber of the dump cylinder b through the oil path 12.

At this time, the oil in the piston rear chamber passes through the oil passage 11 and returns to the tank 10 from ports b and f of the dump cylinder directional control valve 6 through oil passages 13' and 13.

Therefore, at this time, the lift arm 1 is raised by the extension of the lift cylinder 4, and the dump cylinder 5 is contracted by the return oil of the lift cylinder 4, thereby causing the tip working machine 3 to perform a scooping operation.

Furthermore, when the lift cylinder directional control valve 7 is switched to the raised position and the dump cylinder directional control valve 6 is switched to the dump position, the lift arm 1 is raised by the extension of the lift cylinder 4, and the lift cylinder 4 is moved upward. The dump cylinder 5 is extended by the returned oil, and the working machine 3 at the tip can be operated for dumping.

In short, when the lift cylinder directional control valve 7 is switched to the up position and the dump cylinder directional control valve 6 is switched to the rake or dump position, the dump cylinder 5
Since the return oil of the lift cylinder 4 is supplied to the front and rear chambers of the piston, when the lift cylinder 4 is raised, the dump cylinder 5 expands and contracts accordingly, allowing the work implement 3 to follow and rotate.

FIG. 5 shows a state in which the lift cylinder directional control valve 7 is switched to the lower position and the dump cylinder directional control valve 6 is set to the dump position.

That is, the hydraulic pressure from the hydraulic pump 9 pushes open the check valve 19 and passes through the oil passage 17 from ports (k and h) to the lift cylinder 4.
is supplied to the front chamber of the piston.

Then, the lift cylinder 4 contracts and the lift arm 1
lower.

The oil in the rear chamber of the piston of the lift cylinder 4 is transferred to the oil passage 1.
It is supplied to the piston rear chamber of the dump cylinder 5 through the oil passages 11 through the oil passages 15 and 15 of the dump cylinder directional control valve 6 through the oil passages 11 and 15, The oil in the front chamber passes through the oil passage 12 and returns to the tank 10 through the oil passages 13' and 13 from ports c and f.

Therefore, at this time, the lift arm 1 is lowered by the contraction of the lift cylinder 4, and the dump cylinder 5 is extended by the return oil of the lift cylinder 4, so that the tip working machine 3 can be operated in a dump operation.

Further, if the lift cylinder directional control valve 7 is left in the lowered position and the dump cylinder directional control valve 6 is switched to the rake position, the lift cylinder 4 is contracted and the lift arm 1 is lowered, and the lift cylinder 4 is The dump cylinder 5 is contracted by the returned oil, and the tip working device 3 can be operated in a scooping manner.

In short, when the lift cylinder directional control valve 7 is switched to the lower position and the dump cylinder directional control valve 6 is switched to the scoop or dump position, the return oil of the lift cylinder 4 flows into the front and rear piston chambers of the dump cylinder 5. Since the dump cylinder 5 is supplied, when the lift cylinder 4 descends, the dump cylinder 5 expands and contracts accordingly, and the working machine 3 can follow and rotate.

The above is an explanation of the operation when the stop valve 8 according to the present invention is closed, and next, the operation when the stop valve 8 is opened will be explained below.

[When the stop valve is opened]

In this case, the dump cylinder directional control valve 6 is kept in the neutral position, and if the stop valve 8 is opened, the operating pressure of the hydraulic pump 9 is When the lift arm 1 is in the lowered position, the hydraulic pressure is not activated, and the lift arm 1 is therefore single-acting.

FIG. 6a shows a state in which the dump cylinder directional control valve 6 is kept in the neutral position and the lift cylinder directional control valve 7 is switched to the raised position.

The resulting wetting of the pressure oil at this time is the same as when the stop valve 8 shown in FIG. 3a is closed, and the lift cylinder 4 independently extends to lift the lift arm 1.

FIG. 6 shows a state in which the dump cylinder directional control valve 6 is kept in the neutral position and the lift cylinder directional control valve 7 is switched to the lowered position.

That is, the pressure oil from the hydraulic pump 9 pushes open the check valve 19 and is applied to the port and from h to the oil passage 17.

At this time, since the stop valve 8 according to the present invention is open, the oil flows toward the oil path 13 and is returned to the tank 10.

Therefore, the acting force of the pressure oil supplied to the front chamber of the piston of the lift cylinder 4 disappears, and since the rear chamber of the piston passes through the tank 10, the lift cylinder 4 is able to hold the lift arm 1, the tip working machine 3, and the cargo. It contracts due to its own weight, and the tip working machine 3 touches the ground and stops.

Therefore, the lift arm 1 becomes free in the vertical direction when the tip working machine 3 is on the ground, and prevents the tractor 2 and the tip working machine 3 from being damaged when traveling in this state.

Further, at this time, the tip working machine 3 can be run while naturally following the unevenness of the ground, and there is no shock and damage can be prevented.

In addition, when the lift cylinder directional control valve 7 is switched to the neutral position and the dump cylinder directional control valve 6 is switched to the rake or dump position, FIG. 4a,
Since the result is the same as the independent operation of the dump cylinder 5 in b, the explanation here will be omitted.

In addition, when transporting the advanced work equipment 3 loaded with agricultural equipment, etc., it travels with both valves 5 and 6 in neutral, but at this time, the oil passage 17 in the front chamber of the lift cylinder 4 When the valve 8 is opened, the oil passage 13 communicates with the tank 10, so the lift arm 1 becomes free only in the upward direction.
The running vibration of the tractor 2 is not directly transmitted to the tip working machine 3,
Absorbs shock and protects the tractor 2 and front loader.

Next, FIG. 7 shows another embodiment of the hydraulic circuit, in which the same parts as in the above embodiment are designated by the same reference numerals.

In this embodiment, the oil passage 15 and check valve 16 of the previous embodiment are abolished, and these are incorporated into the flow passage for controlling the flow of pressure oil at the ascending and descending positions inside the lift cylinder directional control valve 7. It is something.

In FIG. 7, 21 is a main relief valve.

The operation in the embodiment shown in FIG. 7 is ultimately the same as that in the previous embodiment, so a description thereof will be omitted here.

FIG. 8 is a hydraulic circuit diagram showing yet another embodiment, in which the same reference numerals indicate the same members as in the previously described embodiment.

In this embodiment, a spacer 2 is provided between the two directional control valves 6 and 7.
In addition, one pump-side port of the lift cylinder directional control valve 7 is added, and a port relief valve 23 is added in the middle of the oil passage 11 on the piston rear chamber side of the dump cylinder 4. be.

In this embodiment, the operation with the stop valve 8 closed is substantially the same as in the embodiment described above.

That is, when the lift cylinder directional control valve 7 is operated independently, the hydraulic oil from the pump 9 is supplied to the piston front chamber or the piston rear chamber of the lift cylinder 4, and the return oil is supplied to the communication oil passage 24 or 25. Spacer 22 from either
The lift cylinder 4 is returned to the tank 10 on the upper left side of the figure, and the lift cylinder 4 is operated independently and in double motion.

Furthermore, when the dump cylinder directional control valve 6 is operated independently, the hydraulic oil from the pump 9 is supplied to the front chamber or the rear chamber of the dump cylinder 5, and the return oil is returned to the tank 10 on the right in the middle of the figure. Thus, the dump cylinder 5 is independently operated in double motion.

Furthermore, when the two directional control valves 6.7 are operated simultaneously, the return oil of the lift cylinder 4 causes the dump cylinder 5 to follow and interlock.

On the other hand, in FIG. 8, the operation when the stop valve 8 is opened is slightly different from that of the previous embodiment.

That is, in this case, when the lift cylinder directional control valve 7 is in the raised position, it is the same as in the previously described embodiment, but when it is in the lowered position, it is slightly different.

Therefore, the case where the lift cylinder directional control valve 7 is set to the lowered position will be explained in order.

First, in this state, if the dump cylinder directional control valve 6 is set to the neutral position, the hydraulic oil from the pump 9 will pass from the stop valve 8 through the spacer 22 and return to the tank 10 on the upper left side in FIG. , no hydraulic pressure acts on the piston front chamber of the lift cylinder 4, and at the same time, the piston rear chamber of the lift cylinder 4 also communicates with the tank 10 from the communication oil passage 24 via the throttle 26 in the spacer 22 or the check valve 27. Therefore, the lift cylinder 4 is in a free state in the vertical direction and descends by its own weight, or after descending, it is in a state where it freely follows the unevenness of the ground.

Next, in the above state, even if the dump cylinder directional control valve 6 is switched to either the dump or scoop position, both cylinders 4
, 5 differ from the previous embodiment in that they can be linked in a follow-up manner in the same way as in FIGS. 5a and 5b.

In addition, in FIG. 8, when the stop valve 8 is left open and the bidirectional control valves 6 and 7 are set to neutral, the lift cylinder 4 becomes free only in the upward direction, and due to the presence of the port relief valve 23, the lift cylinder 4 is free to move upwardly. The cylinder 5 is also capable of escaping if an external force greater than the set pressure is applied in the direction of contraction.

Note that if the stop valve 8 is left open, the valve 7 is set to neutral, and the valve 6 is switched to the dump or rake position, 1. Hydraulic oil from the pump acts on the front chamber of the piston of the lift cylinder 4 through the stop valve 8, but the rear chamber of the piston of the lift cylinder 4 is locked by the lock port of the directional control valve 7 in the neutral position, so that no operation occurs. The system becomes locked without any movement, and only the dump cylinder 5 performs the necessary operations.

I can do it.

In short, in the embodiment shown in FIG. 8, if the stop valve 8 is closed when the lift cylinder 4 is operating independently, the lift cylinder 4 can be made double-acting;
By doing so, the lift cylinder 4 can be made single-acting.

As explained above, this invention consists of a lift cylinder that raises and lowers a lift arm that is pivotally connected to a tractor, a dump cylinder that scoops and dumps a tip working device that is pivotally connected to the tip of the lift arm, and a lift cylinder that raises and neutralizes the lift cylinder. - Equipped with a lift cylinder directional control valve that switches to the lower position and a dump cylinder directional control valve that switches the dump cylinder to the scoop, neutral, and dump positions, and these two directional control valves control the return oil from the lift cylinder. Dan.

In an agricultural front loader that is configured to have a combination of a circuit that simultaneously operates the lift cylinder and the lift cylinder and a circuit that operates each of the lift cylinder and dump cylinder independently, an oil passage connected to the front chamber of the piston of the lift cylinder. A branch connection is made to the oil tank through a stop valve that can be opened and closed in the middle of the lift, so if the stop valve is left open, the lift cylinder can be switched independently, and in this case, no undue force is applied to the tractor. In addition to preventing damage, it is also possible to prevent damage to the tip working machine.

Therefore, it is possible to prolong the life of working machines (especially fork machines), tractors, and front loaders, which is economical.

In addition, since the work machine can be aligned on uneven ground, it has excellent maneuverability and allows safe work.

Furthermore, it is safe because it absorbs the shock during cargo handling, and the front wheels of the four-wheel drive tractor do not float, allowing the tractor to fully utilize its traction power.

In addition, if the stop valve is closed, the lift cylinder can be switched to double action, and in this case, it is possible to pressurize the load and lift the front wheels of the tractor, allowing for escape from slippage and front wheel tread. etc. can be easily adjusted.

Furthermore, switching between single-acting and double-acting lift cylinders can be done simply by opening and closing the stop valve depending on the work conditions, so the switching operation can be done with a single touch, expanding the range of cargo handling work and increasing tractor operating efficiency.・It is capable of fully demonstrating double-acting functions.

Furthermore, the structure is simple and can be implemented at low cost.

In addition, if the front loader is a detachable lift arm type, the lift arm can be easily attached and detached, and has many excellent advantages.

[Brief explanation of the drawings] Figure 1 is a schematic side view of the loading machine to which the present invention is applied;
The figure shows the hydraulic control path diagram when the stop valve is closed and the directional control valves for both cylinders are in the neutral state, Figure 3 a, b
4a and 4b are hydraulic circuit diagrams showing the independent operation of the directional control valves for both cylinders when the stop valve is closed, and fig. 3a shows the directional control valve for the lift cylinder in the raised position. FIG. 3b shows it in the lowered position. FIG. 4a shows the state in which the dump cylinder directional control valve is switched to the rake position, and FIG. 4b shows the state in which it is switched to the dump position. Figures 5a and 5b are hydraulic circuit diagrams when both cylinder directional control valves are operated simultaneously with the stop valve closed, and Figure 5a is a hydraulic circuit diagram with the lift cylinder directional control valve in the raised position. Fig. 5b shows a state in which the lift cylinder directional control valve is switched to the lower position and the dump cylinder directional control valve is switched to the dump position. show. Figures 6a and 6b are hydraulic circuit control diagrams showing the independent operation of both cylinder directional control valves when the stop valve is opened, and Figure 6a shows the dump cylinder directional control valve in the neutral position. FIG. 6b shows a state in which the lift cylinder directional control valve has been switched to the lower position from the state shown in FIG. 6a. 7 and 8 show other embodiments of the hydraulic circuit according to the present invention. 1... Lift arm, 2... Tractor, 3... Work equipment, 4... Lift cylinder, 5... Dump cylinder, 6 ...Directional control valve for dump cylinder, 7 ...Directional control valve for lift cylinder, 8 ...Stop valve, 9
...Hydraulic pump, 1o...Tank, 1
6, 19...Check valve, 21...Main relief valve. 14°

Claims (1)

[Scope of utility model registration request] For lift cylinders that are pivotally attached to the tractor or to raise and lower the foot arm, dump cylinders that are pivotally attached to the tip of the lift arm and that scoop and dump tip working equipment, and lift cylinders that switch the lift cylinder to the raised, neutral, or lowered positions. A circuit that is equipped with a directional control valve and a directional control valve for the dump cylinder that switches the dump cylinder to the scoop, neutral, and dump positions, and these two directional control valves feed return oil from the lift cylinder to the dump cylinder and operate them simultaneously. In an agricultural front loader that is configured to combine a circuit for operating each of the lift cylinder and dump cylinder independently, there is a stop that can be opened and closed in the middle of the oil passage connected to the piston front chamber of the lift cylinder. An agricultural front loader characterized by having a branch connection to an oil tank via a valve.