JPH0243451B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for raising and lowering a rice transplanter by moving its wheels up and down using hydraulic pressure.

[Conventional technology and its problems]

Conventionally, it has been common practice to use a single-acting hydraulic cylinder for this type of elevation, as described in, for example, Japanese Utility Model Application Publication No. 55030/1983.

However, the single-acting hydraulic cylinder has various problems when lowering the aircraft from the maximum raised position, as will be described in detail later.

The present invention aims to solve this problem.

[Means for solving the problem] In order to achieve this object, the present invention provides a rice transplanter in which running wheels are mounted on the body frame of the rice transplanter so as to be movable up and down via a swing case extending rearward. A double-acting hydraulic cylinder for raising and lowering the wheels is provided between the fuselage frame and the swing case, and the double-acting hydraulic cylinder is provided with a double-acting hydraulic cylinder that is installed at the point when the downward movement of the traveling wheels by the hydraulic cylinder reaches approximately the maximum. The hydraulic pressure cylinder is configured to include a hydraulic pressure relief passage that communicates the piston rear chamber and the piston front chamber with each other.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 indicates a body frame of a rice transplanter, and the body frame 1 has an engine 2 on the top surface.
The transmission case 3 has a U-shape in plan, consisting of a transmission case 3 to which the transmission case 3 is attached, and a pair of left and right hollow side frames 4 and 5 extending rearward from both left and right ends of the transmission case 3. A swing case 6 extending rearward between both side frames 4 and 5
The front end of the swing case 6 is rotatably pivoted, and a running wheel 7 is provided at the tip of the swing case 6 and is located on the center line in the width direction of the fuselage frame 1. It is rotatably driven via the case 3 and a chain (not shown) in the swing case 6.

Seedling planting cases 8 and 9 are fixed to the rear ends of both side frames 4 and 5, respectively, and the two seedling planting cases 8 and 9 are connected by a gate-shaped connecting frame 10, so that the entire structure is The base end of a lever 11 is rotatably attached to a pin 12 on the inner surface of the midway part of one side frame 5, and the base end is attached to the tip of the lever 11. The tip of a piston rod 16 of a piston 15 in a double-acting hydraulic cylinder 14 is pivoted by a pin 13 to the front end of the lever 11, and the tip of the lever 11 and the arm 18 protruding from the swing case 6 are connected by a pin 17. By connecting them through a link 19, the traveling wheels 7 are moved up and down by the operation of a double-acting hydraulic cylinder 14, and the entire rice transplanter is raised and lowered.

Reference numerals 20 and 21 in the figure indicate a pair of left and right operating handles extending rearward from the seedling planting cases 8 and 9, and the operating handles 20 and 21 are bent in an upwardly inclined shape, and the inclined portions thereof are bent upwardly. A rear-tilting seedling stand 24 is provided on the top surface and supported by a guide rail 22 and a rail mechanism 23 horizontally mounted between both handles so as to be movable laterally to the left and right. On the inside of both seedling planting cases 8 and 9, there are swinging seedling planting mechanisms 26 and 27 that reciprocate between the seedling outlet in the guide rail 22 at the lower end of the seedling platform 24 and the field surface 25. Each is provided.

Further, reference numerals 28 and 29 in the figure refer to the traveling wheels 7.
A pair of left and right floats 28 and 29 are located on the left and right sides of the handles 20 and 21, respectively.
The front end is attached to both side frames 4 and 5 via a link 31 so as to be vertically movable.

Further, reference numeral 32 in the figure indicates a rotary type 4-port 3-position hydraulic switching valve attached to the side surface of the transmission case 3, etc., and the valve is connected to the pump port P of the switching valve 32 through a circuit 33 to be driven by the engine 2. Connect the hydraulic pump 34 to be used, and connect port A to circuit 3.
5 to the piston rear chamber 15' of the double-acting hydraulic cylinder 14, and port B to the piston front chamber 15'' through the circuit 36, and when the spool 37 of the switching valve 32 is in the neutral position, the port A and B are both closed, ports P and R communicate with the through hole 37', the operation of the hydraulic cylinder 14 is stopped, and the spool 3
7 rotates in the counterclockwise direction of arrow a, the ports A, B and R are switched to communicate with each other, and the piston 15 protrudes from the hydraulic cylinder 14, thereby lowering the traveling wheel 7. In other words, when the body is raised and the spool 37 is rotated clockwise as indicated by the arrow b, port A is switched to communicate with port R and port B is communicated with port P, and the piston 15 moves backward, thereby connecting the traveling wheels. It is configured to raise 7 degrees, that is, lower the aircraft.

Reference numeral 38 denotes a horizontal shaft that is rotatably supported through bearings 39, 39 in a substantially horizontal direction with respect to the rear upper surface of the transmission case 3. One end of the horizontal shaft 38 has a substantially triangular control shaft. When the control link 40 is in the position shown by the solid line in FIG. 4, the base end of the link 40 is rotatably fitted, and the lever 41 attached to the tip of the control link 40 and the spool 37 of the switching valve 32 is connected. When the switching valve 32 is in the neutral position, the control link 40
The switching valve 32 is connected via a rod 42 so that the counterclockwise rotation of the control link 40 switches the switching valve 32 to raise the fuselage, and the clockwise rotation of the control link 40 switches the switching valve 32 to lower the fuselage. , a pin 43 extending substantially parallel to the axial direction of the horizontal shaft 38 and in the direction of the control link 40 is fixed to the horizontal shaft 38, and its tip is brought into contact with the back surface of the control link 40, so that the pin 43 and the control link A spring 44 is mounted between the horizontal shaft 38 and the control link 40 to press and bias the control link 40 against the pin 43, while the base ends of a pair of left and right levers 45 and 46 are mounted on both ends of the horizontal shaft 38. The tips of the levers 45, 46 and the pair of left and right floats 28, 29 are connected via rods 47, 48, respectively, so that the vertical movement of each float 28, 29 causes the levers to move freely. The levers 45 and 46 are configured to move up and down, and a pin shaft 49 is provided on the horizontal shaft 38 at an intermediate position between the levers 45 and 46 and protrudes in a right angle direction. A thread take-up shaft 51 extending parallel to the horizontal shaft 38 is fixed to the boss 50 which is rotatably fitted into the boss 50, and both ends of the thread take-up shaft 51 are connected to slotted holes projecting in the middle of the levers 45, 46. 4
5' and 46', the horizontal shaft 38 is rotated counterclockwise or clockwise by an angle half the vertical movement of either of the left and right levers 45, 46. Configure.

Furthermore, reference numeral 52 in the figure is a manual operation rod for manually raising and lowering the aircraft body, and a long slot 53 provided at the tip thereof is slidably inserted into a pin 54 protruding from the side surface of the control link 40. The shaft portion 55 that is engaged and fixed to the proximal end of the manual operation rod 52 is slidably inserted into the round hole 57 of the support bracket 56 attached to the portal frame 10, and the grip portion 58 is attached to the tip of the shaft portion 55. A spring 59 provided between the support bracket 56 and the shaft portion 55 allows the pin 54 of the control link 40 to be located approximately in the middle of the slotted hole portion 53 when the switching valve 32 is in the neutral position. while holding the support bracket 56
is provided with a slot 60 that communicates with the round hole 57, and when the manual operating rod 52 is pulled backward in the direction of arrow c,
The switching valve 32 is configured to be switched to raise the fuselage via the control link 40, and the constricted portion 61 of the shaft portion 55 is fitted into the slot 66 in the rearward pulled position. Configure it so that it can hold.

The piston rod 16 in the double-acting hydraulic cylinder 14 is connected to the port A of the switching valve 32.
a piston rear chamber 15' communicating with the via passage A';
A passage 62 is bored through the piston front chamber 15'' which communicates with the port B of the switching valve 32 via a passage B', and a passage 62 is formed in the passage 62 from the piston front chamber 15'' to the piston rear chamber 15''. While providing a check valve 63 configured to open only and a throttle orifice 64,
Piston rod 16 in piston front chamber 15''
A bush 67 for opening and closing the hydraulic pressure relief passage 65 with a ball-shaped valve 66 that bypasses the check valve 63 is slidably fitted therein, and the bush 67 is inserted between the bush 67 and the piston 15. The provided spring 68 holds the hydraulic pressure relief passage 65 in a normally closed state, and when the piston 15 approaches its maximum stroke, the bush 67 contacts the inside of the front cover 69 of the cylinder 14 and closes the hydraulic pressure relief passage 65. is configured to open into the piston front chamber 15''.

In this configuration, the seedlings are supplied onto the seedling stand 24, and when the engine 2 is started, the running wheels 7,
By driving both seedling planting mechanisms 26, 27 and the seedling platform 24, the seedling pine on the seedling platform 24 is divided into individual plants by the vertically swinging seedling planting mechanisms 26, 27 while the rice transplanter is moving forward. After that, the float 28,
After the ground has been leveled in step 29, the crops are planted in two rows in the field 25.

When the plowing depth increases during this rice planting work,
As the aircraft descends to approach the field scene 25, the planting depth of the seedlings in the field scene 25 becomes deeper, but then both floats 28 and 29 that touch down on the field scene 25
approaches the fuselage, and both levers 45 and 46 simultaneously rotate upward via rods 47 and 48, so that the balance shaft 51, which has both ends locked to both levers 45 and 46, rotates around the pin shaft 49. Therefore, the horizontal shaft 38 with the pin shaft 49 is rotated counterclockwise and the control link 40 and the spool 3 of the switching valve 32 are rotated counterclockwise.
7 rotates in the direction of raising the aircraft as indicated by arrow a. At this time, the rising distance l of both floats 28 and 29 to the aircraft body is
If the spool 37 in the switching valve 32 is within the valve stroke L from the neutral position to the aircraft up position or aircraft down position, the switching valve 32 will not switch to the aircraft up position, but if l exceeds L, it will switch. The valve 32 is switched to lift the machine body, hydraulic pressure is sent from ports A and A' to the piston rear chamber 15' of the hydraulic cylinder 14, and the traveling wheels 7 move downward, so that the machine body rises from the field surface 25. In addition, when the plowing depth becomes shallower, the height of the machine rises away from the field scene 25, and the planting depth of the seedlings in the field scene 25 becomes shallower. Both floats 2 grounded on surface 25
8 and 29 are separated from the aircraft, and both levers 45 and 46 are
are rotated downward at the same time, the horizontal shaft 38, control link 40, and switching valve 32 are rotated clockwise in the direction of lowering the fuselage, and the descending distance l of both floats 28 and 29 relative to the fuselage is equal to the valve stroke L. When the machine exceeds the limit, the switching valve 32 is switched to the machine lowering position, and hydraulic pressure is sent from ports B and B' to the piston front chamber 15'' of the hydraulic cylinder 14, and the traveling wheels 7 move upward, so that the machine moves to the field position. The seedling planting depth can be automatically controlled to remain approximately constant despite changes in the plowing depth, such as by descending relative to the plowing surface and returning to the original planting depth.

During the rice planting work, both floats 2
Only the float on one side of the floats 8 and 29, for example, the right float 29, moves up and down depending on the roughness of the field 25, and the right lever 46, which is linked to the right float 29 through a rod 48, moves up and down. When the right lever 46 moves up and down, only about half of the movement is transmitted to the horizontal shaft 38 due to the rocking of the balance shaft 51. In other words, the up and down movement of the right float 29 is transmitted to the horizontal shaft 38 due to the swing of the balance shaft 51. The switching valve 32 will switch from the neutral position to raise the aircraft or lower the aircraft unless the height 21, which is approximately twice the rising or descending height l when switching the switching valve 32 from the neutral position, is exceeded by simultaneously moving up and down. Therefore, even if the float on one side moves up and down due to relatively small irregularities in the field, the aircraft will not move up and down in response to this, in other words, the aircraft will not move up and down finely. Only when both floats 28 and 29 simultaneously move up and down above a certain level, the machine moves up and down in response to this, and the height relative to the field is automatically controlled to a substantially constant value.

In addition, during rice planting work, if the aircraft tilts to the left or right with respect to the direction of travel, both the left and right floats may
When the levers 8 and 29 move up and down in opposite directions, the balance shaft 51, whose ends engage the levers 45 and 46 that are interlocked with the levers 8 and 29, is pinned as shown by the one-dot chain line and the two-dot chain line in FIG. Since the machine only swings about the shaft 49 and does not rotate the horizontal shaft 38, the switching valve 32 is not switched, and the body is not raised or lowered.

When the rice transplanting operation described above has progressed to the edge of the bank and the rice transplanter is to be rotated, the seedling planting mechanisms 26, 27 and the seedling platform 24 are stopped, and the manual operation rod 5 is turned off.
2 in the direction of arrow c, and by fitting and locking the constricted portion 61 of the shaft portion 55 into the slot 60 of the support bracket 56, the control link 40 and the spool 37 of the switching valve 32 move in the direction of the arrow a. By rotating clockwise, the switching valve 32 switches to raise the aircraft, allowing the aircraft to rise significantly and make a turn in the direction of the aircraft.When this turn is completed, the manual operation rod 5
2 is released from the support bracket 56, the original automatic control is restored and the machine is automatically controlled to be constant with respect to the field scene.

In the position where the aircraft body is raised to the maximum level by the above-mentioned manual operation, the hydraulic pressure of the hydraulic pump 34 is constantly applied to the piston rear chamber 15' of the hydraulic cylinder 14.
This oil pressure maintains the aircraft at its maximum raised position. With the rice transplanter in the maximum raised position, when the rice transplanter is driven forward by the driving wheels 7 when turning in the direction, running on the road, or crossing a ridge, the swing case 6 will move as shown by the arrow D in FIG. As shown in , a rolling reaction force is generated, and this rolling reaction force overcomes the weight of the aircraft and lifts the aircraft. In such a case, if the hydraulic cylinder that raises and lowers the aircraft is a conventional single-acting hydraulic cylinder, even if the switching valve is switched to lower the aircraft, the aircraft will not be able to descend due to the rolling reaction force mentioned above. The response becomes sluggish and the response is extremely low. If this is particularly severe, it becomes impossible to lower the aircraft from the maximum raised position, and each time the drive of the traveling wheels 7 is stopped to eliminate the rolling reaction force. This made the operation troublesome.

In contrast, the present invention uses the reciprocating hydraulic cylinder 14 for raising and lowering the aircraft as described above, and the bush 67 contacts the front cover 69 as the piston 15 moves forward. A hydraulic pressure relief passage 65 is provided which opens to communicate the piston rear chamber 15' and the piston front chamber 15'' with each other. When the position is reached, the hydraulic pressure relief passage 65 opens and the piston rear chamber 15'
The hydraulic pressure leaks to the piston front chamber 15'' through the hydraulic pressure relief passage 65, and the pressure in the piston rear chamber 15' decreases, and when the switching valve 32 is switched to the body lowering position, the pressure immediately leaks into the piston front chamber 15''. Since hydraulic pressure is applied and the aircraft is forcibly lowered by this hydraulic pressure, the aircraft not only has good responsiveness when descending from the above-mentioned raised position and can descend quickly, but also can drive the traveling wheels 7 as before. It is possible to descend with an extremely simple operation without having to stop each time.

In this case, if a check valve such as a spherical valve 66 is provided in the hydraulic pressure relief passage 65, the response to descent from the maximum raised position will be further improved.
In the above embodiment, the check valve 63 and the throttle orifice 64 provided in the passage 62 connecting the piston rear chamber 15' and the piston front chamber 15'' in the hydraulic cylinder 14 close the piston front chamber during the minimum stroke of the hydraulic cylinder. 15" to the piston rear chamber 1
5' to reduce the pump load.

[Action/effect of the invention]

As described above, according to the present invention, a double-acting hydraulic cylinder is used to raise and lower the traveling wheel, and a hydraulic pressure relief passage is provided for this double-acting hydraulic cylinder, so that when the traveling wheel is lowered to the maximum, In other words, when descending the aircraft from the maximum raised state, it is possible to reliably prevent the aircraft from becoming unable to descend or becoming insensitive due to the rolling reaction force of the running wheels. This has the effect of improving the operability of raising and lowering the rice transplanter.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a side view of the rice transplanter, FIG. 2 is a plan view of the rice transplanter, FIG. 3 is a perspective view of the lifting device, and FIG. 4 is an enlarged view of the lifting control unit. ,
Figure 5 is a sectional view taken along the line V-V in Figure 4, and Figure 6 is a cross-sectional view of Figure 5.
7 is a sectional view of FIG. 5, FIG. 8 is a sectional view of FIG. 4, and 9 is a sectional view of FIG.
The figure is an enlarged longitudinal sectional front view of the hydraulic cylinder for lifting.
FIG. 0 is a diagram showing the operating state of FIG. 9. 1... Airframe frame, 6... Swing case,
7... Traveling wheel, 14... Double-acting hydraulic cylinder,
15... Piston, 16... Piston rod, 3
2...Switching valve, 34...Hydraulic pump, 15'...
Piston rear chamber, 15"...Piston front chamber, 65"...
...Hydraulic pressure relief passage, 67...Button, 68...Spring.

Claims (1)

[Claims] 1. In a rice transplanter in which running wheels are attached to the body frame of the rice transplanter via a swing case extending rearward so as to be able to move up and down, a double-acting type for raising and lowering the wheels between the body frame and the swing case. A hydraulic cylinder is provided, and the double-acting hydraulic cylinder is configured to connect a rear piston chamber and a front chamber of the piston in the hydraulic cylinder to each other when the downward movement of the traveling wheel by the hydraulic cylinder reaches a substantially maximum value. A lifting device for a rice transplanter characterized by having a hydraulic pressure relief passage.