JPH065A - Device for fixing three-point link hitch - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to fix the 3-point link hitch during excavation work using a backhoe or the like. [Structure] Installed in a 3-point link hitch for connecting work equipment,
The three-point link hitch fixing device includes a lock cylinder composed of both rod cylinders arranged in the three-point link hitch,
The lock cylinder is configured by a two-position switching valve interposed between the cylinder chamber on the extension side and the cylinder chamber on the contraction side. One end of the lock cylinder is connected to the working vehicle side and the other end is connected to three. Connected to the tip side of the lower link of the point link hitch, and sliding movement of the two-position switching valve in the closing direction,
The hydraulic pressure is generated when the working machine moves downward, or is linked to the downward operation of the operating lever for operating the working machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention stabilizes a work vehicle and a work machine when the work machine is connected to a work vehicle such as a tractor or a carrier through a three-point link hitch to perform a predetermined work. The present invention relates to a three-point link hitch fixing device for keeping a state.

[0002]

2. Description of the Related Art A work vehicle, such as a tractor, is used with various work machines connected to a rear portion or a front portion thereof.

When the backhoe is attached to the rear or front of the tractor, for example, of the working machines, a three-point link hitch mounted on the tractor is generally used for the connecting work. is there.

This three-point link hitch (1) is, as shown in FIG. 7, a pair of left and right lift arms (2), a lift rod (3),
It consists of a lower link (4) and a top link (5), and the lift arm (2) is integrally connected by a crank shaft (6).

Then, by operating the single-acting hydraulic cylinder to rotate the lift arm (2) upward,
The lower link (4) is rotated upward about the fulcrum (7).

Further, the top link (5) is a double-acting hydraulic cylinder integrally built into the top link (5), and its total length is variable.

In order to connect the working machine, for example, the backhoe (10) to the tractor (A) using the above-mentioned three-point link hitch (1), as shown in FIG. 8, the lower link of the three-point link hitch (1) ( The tips of 4) and the top link (5) are fixed to the lower end and the upper end of the support frame (11) of the backhoe (10), respectively.

In the figure, (13) is the first arm supported by the support frame (11) through the swing frame (12), and (14) is
One end is connected to the first arm (13) and the other end is the bucket (15)
The second arm connected to (16) (17) (18) is
These are first to third hydraulic cylinders for varying the angles of the arms (13) and (14) and the bucket (15).

Reference numeral (19) in the figure denotes an earth discharging plate fixed to the support frame (11).

[0010]

As described above, the method of connecting the backhoe (10) to the rear part of the tractor (A) by using the three-point link hitch (1) equipped on the tractor (A) is described. If you take it, it will be easier to connect the two, and at the same time when working,
Since the load on the backhoe (10) is transmitted to the tractor (A) via the three-point link hitch (1) designed to receive the load, there is no fear that the tractor (A) will be overloaded.

However, the above-mentioned three-point link hitch (1) is designed on the basis of the fact that the central working machine mounted on the tractor (A), that is, the rotary, plow and the like are connected to perform the work. Therefore, a single-acting cylinder is used as a cylinder for driving the lower link (4), and it is impossible to apply downward pressure by the cylinder.

Therefore, when the backhoe (10) is attached to the rear part of the tractor (A) via the three-point link hitch (1),
Since the point link hitch (1) is free to move upward, there was a problem that it could not be dug sufficiently by the backhoe (10).

Further, as shown in FIG. 9, only when working with the backhoe (10), the main body side of the tractor (A) and the backhoe (1) are
It is conceivable to interpose a fixing bracket (20) between the support frame (11) of (0) and prevent the backhoe (10) from escaping upward during work. When operating the hitch (1), the fixing metal fittings (20) had to be removed one by one, and there was a problem that the work was very troublesome.

Further, as shown in FIG. 10, a double-acting type for fixing the three-point link hitch (1) between the main body side of the tractor (A) and the tip of the lower link (4) of the three-point link hitch (1). It is conceivable to interpose the fixed cylinder (21) of this, but if this is done, it becomes necessary to provide a switching valve dedicated to the fixed cylinder (21), and at the same time, when operating the three-point link hitch (1),
The fixed cylinder (2
There was a problem that it was necessary to expand and contract 1), the structure became complicated, and at the same time the operability was significantly reduced.

[0015]

[Means for Solving the Problems] With a single-acting cylinder,
A working machine equipped with a lower link supported so that a force is applied only when it is rotated upward and a top link arranged above the lower link, and is equipped at the front or rear of the working vehicle. A 3-point link hitch fixing device that is incorporated into a 3-point link hitch for connection,

A lock cylinder composed of both rod cylinders arranged in a three-point link hitch, a two-position switching valve interposed between a cylinder chamber on the extension side of the lock cylinder and a cylinder chamber on the contraction side. Then

One end of the lock cylinder is connected to the working vehicle side, and the other end is connected to the tip end side of the lower link of the three-point link hitch,

The sliding movement of the two-position switching valve in the closing direction is performed by the hydraulic pressure generated when the work machine moves downward, or is interlocked with the downward operation of the operating lever for operating the work machine. It was made to let.

[0019]

As described above, if the lock cylinder is interposed in the three-point link hitch and the working machine connected to the work vehicle by the three-point link hitch descends, the lock cylinder is locked. When a backhoe or the like is used as the working machine, the three-point link hitch is automatically locked when the backhoe performs a digging operation to prevent the working machine from escaping upward.

[0020]

1 shows a three-point link hitch fixing device (30) according to the present invention.

In the figure, (A) is a tractor, (1) is a three-point link hitch equipped on the tractor (A), (4) is a lower link of the three-point link hitch (1), and (5) ) Is the top link.

(10) is a backhoe connected to the tractor (A) by a three-point link hitch (1), and this backhoe (10) is supported by a support frame (11) via a swing frame (12). First arm (13), one end of which is the first arm (13)
To the second arm (14), the other ends of which are connected to the bucket (15), the first and second arms (13) and (14), and the first to the first to change the angle of the bucket (15). 3 hydraulic cylinders (1
6) (17) (18).

Also, an earth-draining plate is provided below the support frame (11).
(19) is installed.

By connecting the lower end of the support frame (11) of the backhoe (10) to the lower link (4) and the upper end to the top link (5), the backhoe (10) is connected to the tractor (A). is doing.

The structure of each member is the same as the conventional one.

Reference numeral (31) is a lock cylinder interposed between the main body side of the tractor (A) and the backhoe (10).

This lock cylinder (31) has a top link of a three-point link hitch (1) with one end of the tractor (A) main body side.
(5) It is supported near the mounting position, and the other end is
It is connected to the tip of the lower link (4) of the three-point link hitch (1) via a shaft.

As shown in FIG. 4, the lock cylinder (31) is of a double rod type and has a volume ratio of the first cylinder chamber (32) on the extension side to the second cylinder chamber (33) on the contraction side. Are made equal.

Further, the first cylinder chamber (32) and the second cylinder chamber (33) of the lock cylinder (31) have a two-position switching valve (34).
And the two-position switching valve (34) is located on the open side, the piston of the lock cylinder (31)
(35) is designed so that it can slide in either the extension side or the shortening side.

The two-position switching valve (34) has one of the cylinders (16), (17) and (18) mounted on the backhoe (10), for example, the first hydraulic cylinder (16). When pressure is generated on the extension side, this pressure is supplied to the two-position switching valve (34) as pilot pressure, and the two-position switching valve (34) is slid to the closing side.

That is, when the backhoe (10) is operated and the backhoe (10) is operated toward the dug side, the two-position switching valve (3
4) automatically slides to the closing side, and the lock cylinder (31) is locked so that it does not move to either the extension side or the shortening side.

In the above structure, the backhoe (10) is connected to the rear part of the tractor (A) by the three-point link hitch (1) equipped with the lock cylinder (31) according to the present invention. The hydraulic circuit is connected so that the pressure on the extension side of the first hydraulic cylinder (16) acts as the pilot pressure of the two-position switching valve (34).

In this state, for example, in order to move the tractor (A) equipped with the backhoe (10), a three-point link hitch is used.
When operating the (1) to lift the entire backhoe (10), the lock cylinder (31) is completely free, so the lock cylinder (31) is an obstacle to the movement of the 3-point link hitch (1). Never be.

Then, as shown in FIG. 1, the backhoe (10) is supported in a working state by the three-point link hitch (1), and in this state, the first to third hydraulic cylinders of the backhoe (10) are supported.
When hydraulic pressure is applied to (16), (17), and (18) to perform excavation work by the backhoe (10), a two-position switching valve that uses the hydraulic pressure from the extension side of the first hydraulic cylinder (16) as the pilot pressure (3
Since 4) moves in the closing direction and the lock cylinder (31) is locked so that it does not move on the extension side or the contraction side, the 3-point link hitch (1) is also locked and the backhoe (10) digs. At this time, it is possible to prevent the trouble that the three-point link hitch (1) pivots upward and becomes an obstacle to the digging work.

Further, after one digging work is completed, the first
When the hydraulic pressure applied to the extension side of the hydraulic cylinder (16) is released, the two-position switching valve (34) moves in the opening direction, and the lock cylinder (31) becomes free again.

Therefore, the backhoe that has finished the digging work
When the (10) is lifted by the 3-point link hitch (1) and the position of the backhoe (10) is slightly moved to perform the next digging work, the lock by the lock cylinder (31) is automatically released. Therefore, dug by the backhoe (10),
It is possible to greatly improve the work efficiency in the case of continuously repeating work such as moving and digging.

FIG. 2 shows the three-point link hitch fixing device (3
1 shows an example of a hydraulic circuit when a backhoe (10) is equipped on a tractor (A) equipped with (0).

In the figure, (16), (17) and (18) are backhoes.
The first to third hydraulic cylinders (10) and (22) are swing cylinders for rotating the revolving frame (12) of the backhoe (10).

(40) is a pump for supplying hydraulic oil to each cylinder, (41) and (42) are first and second three-position switching valves communicating with the pump (40), (43) Is a first two-position switching valve (44) for connecting the first three-position switching valve (41) and either one of the first and second hydraulic cylinders (16) and (17).
Is the second 3-position switching valve (42) and the third hydraulic cylinder (18)
Alternatively, it is a second two-position switching valve for connecting to either one of the swing cylinders (22).

(45) is the first and second three-position switching valve (4
1) (42) and an operation lever for operating the first and second two-position switching valves (43) (44), (31) a lock cylinder, (34)
Is a two-position switching valve for controlling locking and unlocking of the lock cylinder (31). This two-position switching valve (34)
Is designed to change the position of the first hydraulic cylinder (16) using the pressure applied to the extension side as the pilot pressure.
When pressure is applied to the extension side, the two-position switching valve (34) slides in the closing direction.

In the above hydraulic circuit, if the operation lever (45) is operated to operate each switching valve (41) (42) (43) (44),
Through controlling the expansion and contraction of the third hydraulic cylinders (16) (17) (18) and the swing cylinder (22), the backhoe (10)
You can control the movement of.

When the hydraulic pressure is applied to the extension side of the first hydraulic cylinder (16) during the above operation, that is, when the backhoe (10) starts the digging operation, the two-position switching valve (3
Since hydraulic pressure is applied to 4) and the 2-position switching valve (34) slides in the closing direction, the lock cylinder (31) is locked and
Since the three-point link hitch (1) is fixed, digging work is performed smoothly.

FIG. 3 shows a second embodiment of the three-point link hitch fixing device (30) according to the present invention. This embodiment controls locking and unlocking of the lock cylinder (31). Use the electromagnetic 2-position switching valve (34) for the 2-position switching valve,
When the operation switch of the electromagnetic 2-position switching valve (34) is installed on the operation lever (45) and the operation lever (45) is operated to the lowering side, the electromagnetic 2-position switching valve (34) is operated. Is turned on to lock the lock cylinder (31).

When the backhoe (10) is operated and the backhoe (10) is operated to operate the operation lever (45), the electromagnetic two-position switching valve (34) is turned off.
When the electromagnetic 2-position switching valve (34) slides in the closing direction, the lock cylinder (31) is locked and the three-point link hitch (1) is automatically locked.

FIG. 5 shows a third embodiment of the three-point link hitch fixing device (30) according to the present invention. The embodiment shown in this drawing shows the first cylinder chamber of the lock cylinder (31). (3
2) and the second cylinder chamber (33) are communicated with each other via the stop valve (36), and the stop valve (36) is manually opened / closed.
(1) can be fixed at any position.

FIG. 6 shows a fourth embodiment of the three-point link hitch fixing device (30) according to the present invention. The embodiment shown in this drawing shows the first cylinder chamber of the lock cylinder (31). (3
2) and the second cylinder chamber (33) communicate with each other via the stop valve (36), and at the same time, the first cylinder chamber of the pump (40) and the lock cylinder (31) via the three-position switching valve (37). (32) and the second cylinder chamber (33) communicate with each other.

The three-point link hitch (1) can be fixed at any position by manually opening and closing the stop valve (36) with the three-position switching valve (37) in the neutral position.

Further, with the stop valve (36) opened, the three-position switching valve (37) is operated to select either the first cylinder chamber (32) or the second cylinder chamber (33) of the lock cylinder (31). If the lock cylinder (31) is extended or shortened by supplying hydraulic pressure to the crab, the expansion and contraction of the lock cylinder (31) will cause 3
The point link hitch (1) can now be moved up and down.

[0049]

As described above, according to the present invention, a three-point link hitch fixing device incorporated in a three-point link hitch for connecting working machines is provided.

A lock cylinder composed of both rod cylinders arranged in a three-point link hitch, a two-position switching valve interposed between a cylinder chamber on the extension side of the lock cylinder and a cylinder chamber on the contraction side. Configure and

One end of each of the lock cylinders is connected to the working vehicle side, and the other end is connected to the tip end side of the lower link of the three-point link hitch.

The sliding movement of the two-position switching valve in the closing direction is performed by the hydraulic pressure generated when the working machine moves downward, or is interlocked with the downward operation of the operating lever for operating the working machine. I made it happen,

When the backhoe performs a digging operation when a backhoe or the like is used for the work vehicle, the lock cylinder is automatically locked and the three-point link hitch is locked, so no special operation is required. Without doing
It is possible to prevent the backhoe from lifting upward.

Further, when the digging operation by the backhoe is completed, the lock of the lock cylinder is automatically released, and the three-point link hitch can be rotated upward. It is possible to perform operations such as operating the point link hitch to lift the backhoe and moving the position of the backhoe very smoothly.

If a stop valve is interposed between the first cylinder chamber on the extension side of the lock cylinder and the second cylinder chamber on the contraction side and the stop valve is opened and closed manually, a three-point link is formed. It is also possible to fix the hitch at any position.

[Brief description of drawings]

FIG. 1 is a side view showing a state in which a fixing device according to the present invention is mounted on a three-point link hitch.

FIG. 2 is a hydraulic circuit diagram showing a hydraulic circuit configuration of a three-point link hitch fixing device according to the present invention.

FIG. 3 is a hydraulic circuit diagram showing a second embodiment of the present invention.

FIG. 4 is a side sectional view showing a lock cylinder according to the present invention.

FIG. 5 is a side sectional view showing a third embodiment of the present invention.

FIG. 6 is a side sectional view showing a fourth embodiment of the present invention.

FIG. 7 is a perspective view showing a three-point link hitch.

FIG. 8 is a perspective view showing a state in which the backhoe is connected to the tractor by using a three-point link hitch.

FIG. 9 is a side view showing a conventional example of a three-point link hitch fixing device.

FIG. 10 is a side view showing a conventional example of a three-point link hitch fixing device.

[Explanation of symbols]

 A tractor 1 3 point link hitch 4 lower link 5 top link 10 backhoe 11 support frame 16 first hydraulic cylinder 30 3 point link hitch fixing device 31 lock cylinder 32 first cylinder chamber 33 second cylinder chamber 34 2 position switching valve 36 Stop valve 45 Control lever

Claims (2)

[Claims] 1. A work vehicle having a lower link supported by a single-acting cylinder so that a force is applied only when it is turned upward, and a top link arranged above the lower link. A three-point link hitch fixing device to be incorporated in a three-point link hitch for connecting working equipment, which is provided at a front part or a rear part, is provided with a lock cylinder composed of both rod cylinders arranged in the three-point link hitch, and a lock cylinder. The extension side cylinder chamber and a shortening side cylinder chamber are provided with a stop valve interposed between the lock cylinder and one end of the lock cylinder.
A three-point link hitch fixing device characterized in that the other end is connected to the tip side of the lower link of the three-point link hitch. 2. A work vehicle having a lower link supported by a single-acting cylinder so that a force is applied only when it is rotated upward, and a top link arranged above the lower link. A three-point link hitch fixing device to be incorporated into a three-point link hitch for connecting working equipment mounted on the front or rear is provided with a lock cylinder composed of both rod cylinders arranged in the three-point link hitch, and a lock cylinder. 2 between the extension side cylinder chamber and the shortening side cylinder chamber
And a position switching valve, one end of the lock cylinder is connected to the working vehicle side,
The other end is connected to the tip side of the lower link of the three-point link hitch, and the sliding movement of the two-position switching valve in the closing direction is performed by the hydraulic pressure generated when the working machine moves downward, or A three-point link hitch fixing device characterized in that it is linked to the downward operation of the operating lever for machine operation.