JPH022565B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a machine body to which a seedling planting device is connected, and a propulsion wheel that can be raised and lowered by hydraulic drive; and a spring is provided which elastically urges the spool of the control valve in the direction of wheel raising operation, and when the ground float is displaced upward against the spring as the ground pressure increases, the control valve is configured to switch to the wheel lowering side, and when the grounding float is displaced downward as the ground pressure decreases, the control valve is switched to the wheel lifting side, and in an interlocking link mechanism between the grounding float and the control valve. providing flexibility to allow the ground float to move upward relative to the control valve spool;
The present invention relates to a wheel elevation control device for a walking rice transplanter equipped with a spring that elastically maintains this flexibility.

In the wheel elevation control device having the above configuration, by forming an elastic flexibility that allows the ground float as a ground pressure detection sensor to move upward relative to the control valve spool, the wheel suddenly falls into the recess of the tiller. When the ground float is pushed up far beyond the movement limit of the control valve spool, the elastic flexibility allows only the ground float to move upward, thereby preventing damage to the link mechanism linking the control valve spool and the ground float. However, this elastic flexibility also works when transmitting the upward displacement of the ground float to the control valve spool, resulting in a decrease in responsiveness.

The present invention makes it possible to reliably transmit the vertical displacement of the ground float to the control valve to perform highly responsive control during normal wheel elevation control operation, and furthermore, the ground float moves unduly strongly and significantly upward. The purpose of this system is to prevent deformation or damage to the linkage mechanism when the linkage mechanism attempts to is configured such that the pressure can be adjusted, and the elastic accommodating spring is installed with an initial pressure applied, and this initial pressure is equal to the biasing force acting on the spool when the spool biasing spring is adjusted to the maximum strength. Or, it is set larger than this.

According to the above characteristic configuration, no matter how the pressure of the spool biasing spring is adjusted to change the sensor sensitivity to an appropriate sensor sensitivity depending on the hardness and softness of the soil in the field, the linkage remains within the movement range of the control valve spool. Elastic flexibility in the mechanism does not substantially work, so the ground float and spool do not displace relative to each other, and the float displacement is reliably transmitted to the spool without delay, allowing control with good responsiveness. It became.

Then, the elastic accommodating spring deforms only when the grounding float is pushed up unduly strongly and greatly, and a force stronger than a predetermined amount acts on the linkage mechanism.
By allowing the ground float to move upward relative to the spool at its limit of movement, deformation and damage to the linkage mechanism can be reliably prevented and durability can be increased.

Embodiments of the present invention will be described below based on the drawings.

The entire walk-behind rice transplanter is shown in FIGS. 1 and 2, and its general configuration is as follows.

An engine 2 and a transmission case 3 are connected in series to the front end of a main frame 1 made of a round pipe arranged in the left and right center of the aircraft.
A four-row seedling planting device 4 and a control handle 5 are attached to the rear of the machine, and a spare seedling stand 51 is installed at the top of the machine. A hollow plastic center grounding float 6 is provided below the engine 2 and extending to the bottom of the seedling planting device 4. Below the seedling planting device 4, a pair of left and right rear grounding floats 7, 7 are deployed. On the left and right sides of the transmission case 3, wheel transmission cases 8, 8, which are vertically swingable about the front fulcrum X, extend rearward, and propulsion wheels 9, 8 are provided at the rear ends, respectively.
9 is installed.

The seedling planting device 4 includes a seedling platform 10 on which pine-shaped seedlings P are mounted side by side in four rows and moves back and forth laterally at a constant stroke, and a seedling platform 10 that cuts a fixed amount of seedlings from the lower end of the seedling platform 10 and places them in the center and the center. Rear ground float 6,
It is composed of four sets of seedling planting mechanisms 11 for planting on the rice field S leveled in stages 7 and 7, and a rear transmission case 12 equipped with these drive mechanisms.

FIG. 6 shows a suspension structure for the propulsion wheels 9, 9.

A hydraulic cylinder 13 is fixed on the main frame 1, and a balance arm 15, which can swing freely around a vertical fulcrum Y, is attached to a bracket 14 attached to the tip of the piston rod 13a. 15 and each wheel transmission case 8,
Arms 16 and 16 erected from 8 are rod 1
7, 17, both propulsion wheels 9, 9 move up and down simultaneously in the same direction as the piston rod 13a moves in and out, and the left and right wheels 9, 9 are configured to be able to move up and down in opposite directions.

The hydraulic cylinder 13 for lifting and lowering the wheels can be controlled automatically and manually, and its detailed structure will be explained with reference to FIGS. 3 to 5.

A three-position switching type control valve 18 is installed on the right side of the transmission case 3 and receives pressure oil from a pump (not shown) that sucks gear oil in the case as hydraulic oil and discharges it under pressure. , this control valve 18 and the hydraulic cylinder 13 are connected by piping. When the spool 19 of the control valve 18 is pulled out backward, the piston rod 13a
When the spool 19 is pushed forward, the piston rod 13a is retracted and the wheels 9, 9 are raised. still,
As shown in FIG. 8, the spool 19 is given an appropriate neutral restoring force by a single coil spring 20 that acts in both forward and reverse directions.

As shown in FIG. 9, a bracket 21 is attached to the right side surface of the mission case 3 via a fulcrum bolt 21a and a fulcrum pin 21b, and a vertical swing link 22 is attached to the fulcrum pin 21b and the fulcrum bolt 21a. The downward arms 23 are pivotally connected to each other, and a push/pull link 24 is connected with a pin to the protruding end of the spool 19, and a pair of front and rear pins 25, 26 are installed on the sides of the push/pull link 24.
is engaged with a vertical elongated hole 27 formed at the lower end of the swing link 22 and an arc-shaped elongated hole 28 formed in the longitudinal direction at the lower end of the downward arm 23, respectively.

Then, the U fixed to the front upper surface of the main frame 1
A coil spring 31 is stretched between one end 30a of a lever 30 attached to one side of the letter-shaped bracket 29 so as to be swingable back and forth, and the upper end of the swing link 22, and the tension of this spring 31 causes the push/pull link 2 to
4 is elastically biased in the direction of pushing the spool 19. Further, the lever 30 is attached to one of the three notched recesses 32 formed on the other side of the bracket 29.
By adjusting the swing of this lever 30, the tension of the spring 31 can be switched and adjusted in three stages.

Further, a horizontal T-shaped link 33 is fixed to the boss portion of the downward arm 23, and this T-shaped link 3
A tension spring 34 is stretched across the lower end of the downward piece 33a of 3 and the rear end of the push/pull link 24, so that the integrated T-shaped link 33 and the downward arm 23 move clockwise with respect to the push/pull link 24. The pin 26 is biased against the front end of the long hole 28.

The central grounding float 6 and the rear grounding floats 7, 7 are each independently supported vertically swingably around a common rear fulcrum Z set near the seedling planting mechanism 11, and the central float 6 is as follows. As shown in , it is linked to the spool 19 of the control valve 18 and is used as a sensor for automatic wheel elevation control.

That is, a first sensor rod 36 is pivotally connected to a U-shaped bracket 35 fixed to the front part of a central ground sensor (hereinafter referred to as a sensor float) 6, and a boss 36a fixed to the upper end of this rod 36
A second sensor rod 37 is inserted through the T-shaped link 33 so as to be slidable up and down, and the upper end of the second sensor rod 37 is pivotally connected to the tip of the rearwardly facing piece 33b of the T-shaped link 33. Said second sensor rod 37
A coil spring 38 whose lower end is supported by the boss 36a is fitted onto the spring 3.
A spring receiving member 39 that receives the upper end of the sensor rod 8 is fixed to the second sensor rod 37 with a pin 40 that can be inserted and removed. This spring receiving member 39 is connected to a pin 40.
The fixing position to the rod 37 can be changed to three levels (up and down) by changing the position of the rod 37. Further, a support piece 39a for receiving the lower end of the boss 36a is integrally provided from the spring receiving member 39, so that even if the spring receiving member 39 is adjusted up and down, the support interval L between the upper and lower ends of the spring 38 does not change. It's summery.

Then, the spring 38 is initially compressed and deformed and assembled to the specified spring support interval L, and this initial pressure is applied to the spool biasing spring 3.
1 is set to be equal to or slightly larger than the sum of the biasing force acting on the spool 19 and the preload force of the neutral restoring spring 20 of the control valve 18.

Next, the operation of the automobile wheel elevation control will be explained.

Fig. 3 shows a control neutral state when the tiller G is at a certain depth; in this state, the wheels 9 are in correct contact with the tiller G, and the machine body is maintained at an appropriate level with respect to the field surface S. There is. At this time, the ground pressure that pushes up the sensor float 6 and the spring 3
1 is balanced, and the spool 19 of the control valve 18 is at the neutral position (n).

While planting in this state, when the machine reaches a deep part of the tiller G, the entire machine begins to sink, and the ground pressure of the sensor float 6 increases. When this float grounding pressure becomes greater than the sum of the biasing force of the spring 31 and the preload force of the neutral restoring spring 20 inside the control valve, the T-shaped link 33 and the downward arm 23 rotate clockwise as a unit and push The pull link 24 is pulled rearward, the spool 19 is switched to the wheel lowering position (d), and the wheels 9, 9 that are in contact with the tiller G are forced to be driven downward, so that the machine body is relatively raised. go. Then, as the body rises, the ground pressure of the sensor float 6 decreases, and when the balanced state is reached again, the spool 19 returns to the neutral position (n) and the wheel lowering operation is stopped.

Conversely, when the plow G becomes shallow and the machine starts to rise relatively from the field S, the sensor float 6
The ground contact pressure decreases and the balance is lost, and the spool 19 is pushed into the wheel raising position (u) by the urging force of the spring 31, and the wheels 9 are raised by the shortening operation of the hydraulic cylinder 13, and the relative The aircraft is lowered. Then, when the float ground pressure increases again to a balanced state as the aircraft descends, the wheel lift is stopped.

In short, the ups and downs of the machine body due to changes in the depth of the tiller G are sensed as changes in the ground pressure of the sensor float 6, and control is based on the vertical displacement of the sensor float 6 relative to the machine body in accordance with this ground pressure variation. The valve 18 is switched and the wheels 9, 9 are controlled to move up and down in the opposite direction to the float displacement direction, and then,
The machine body is always maintained at a substantially constant level with respect to the field surface S, and the planting depth is stabilized.

In this case, the first relatively elastic
Since the spring 38 interposed between the second sensor rods 36 and 37 is assembled with an initial pressure greater than the spool biasing force by the spring 31, the spool 19 is moved from the neutral position (n) to the wheel lowered position (d). When operating to the side, the spring 38 is not compressed and deformed, and the upward displacement of the sensor float 6 is transmitted to the spool 19 via the T-shaped link 33 and the downward arm 23 without delay. In particular, if the tiller G suddenly falls into a deep place or the sensor float 6 rides on a foreign object on the field S, the spool 19 is pulled out to the stroke end and the T-link 33 is rotated clockwise. In the state where the rotation is prevented, the float 6 is still strongly pushed up, and when this float grounding pressure becomes greater than the initial pressure of the spring 38, the spring 38 is compressed and deformed for the first time, and the sensor rod 36 , 37 portions are prevented from being deformed or damaged.

The spool biasing spring 31 is adjusted appropriately depending on the hardness and softness of the field. In a field where the field surface S is soft, the ground pressure will not increase sufficiently unless the sensor float 6 sinks significantly, and the wheel lowering control will not be possible. Since there is a delay, in this case, the tension of the spring 31 is adjusted weakly to reduce the reference float grounding pressure at the neutral time of control, and sensitive control with high sensor sensitivity is performed. On the other hand, in a field where the field surface S is hard, even a small relative vertical displacement between the field surface S and the machine body will cause large fluctuations in the float contact pressure, and even small changes in the tiller G or unevenness of the field surface S will result in frequent wheel control. If this happens, the stability of the aircraft will be more likely to be compromised. Therefore, in such a case, the tension of the spring 31 is set strongly to increase the reference float grounding pressure at the neutral time of control, and highly stable control with low sensor sensitivity is performed.

Also, the spring receiving member 39 is connected to the second sensor rod 37.
The reference attitude of the sensor float 6 relative to the aircraft body at the time of neutral control can be adjusted by adjusting the fixed position up and down with respect to the body and increasing/decreasing the overall length of the first and second sensor rods 36, 37.

For example, in a field where the rice field S is weak, the spring receiving member 3
Adjust 9 downward to remove the first and second sensor rods 3.
6. Lengthen the entire 37. Then, the attitude of the sensor float 6 supported by the rear fulcrum Z at the controlled neutral time is tilted forward. Therefore, in this case, the front part of the float comes into contact with the surface S a lot, and
The sinking of the aircraft can be detected more sensitively.
Further, in a field where the field surface S is hard, the spring receiving member 39 is adjusted upward to shorten the entire sensor rod. Then, in this case, in the sensor float 6, the elevation angle of the bottom surface of the front part of the float with respect to the field surface S becomes large in the standard state, and the unevenness of the field surface S is smoothly guided under the bottom surface of the float, and it becomes easy to press and level it without strain, and
As the front part of the float tends to float, the sensor sensitivity decreases, making it possible to perform control that is less susceptible to small changes in the tiller G and unevenness of the field surface S.

Even if the reference posture of the sensor float 6 is adjusted in this way, the vertical support interval L of the spring 38 is constant, the initial pressure application state remains unchanged, and the linkage characteristics between the sensor float 6 and the control valve 18 remain unchanged. .

The control valve 18 can also be operated manually, and the structure for this purpose will be described below.

A lever 41 for elevating the aircraft (for elevating wheels) provided at the rear end of the push/pull link 24 and the control handle 5
The release wire 42 has been installed for a long time, and when the lever 41 is set to the "auto" position (A) of the lever guide 43, the inner wire 42a of the release wire 42 is pushed forward, and the push/pull link is pushed out. The inner wire end fitting 45 moves forward inside the U-shaped connecting fitting 44 which is pivotally supported by a pin at the rear end of the inner wire 24, and this fitting 45 and the connecting fitting 44 move forward.
Place the spool 19 in the neutral position (n) between the bottom of the
A gap c is created that is larger than the stroke for shifting from to the wheel lowered position (d). Therefore, in this state, the push/pull link 24 can move back and forth over the entire range of spool operation, allowing the aforementioned control operation to be performed.

Furthermore, when the lever 41 is switched to the "body up (wheel down)" position (U) and locked and fixed, the inner wire 42a is pulled rearward beyond the gap c, thereby causing the inner wire 42a to The spool 19 is pulled out to the wheel lowering position (d), and the aircraft is raised by lowering the wheels.

Furthermore, when the lever 41 is locked and fixed in the "neutral" position (N), the inner wire 42a is pulled rearward by the distance c, and in this state, the push-pull link 2
The forward movement of 4 connects the wire end fitting 45 and the connecting fitting 4.
It is blocked by contact with 4. Therefore, if you first switch the lever 41 to the "aircraft up" position (U) to raise the aircraft to a desired height, and then switch the lever 41 to the "neutral" position (N), the sensor float 6 will float. However, the spool 19 connected to the push/pull link 24 that is abutted and checked as described above is held at the neutral position (n), allowing the aircraft to be maintained at any desired height, and when the seedling planting device 4 is being used, such as when traveling on a road. It is used when driving while floating above the ground.

Note that the wheel lift lever 41 is connected to the seedling planting device 4.
The wire is also connected to a clutch (not shown) that cuts off the power to the "auto" position (A), and the clutch engages in the "neutral" position (N) and "aircraft up" position.
At position (U), the clutch is in a disengaged state. or,
This lever 41 can also be locked and held in the "swivel" position (T), which corresponds to the intermediate position between the "auto" position (A) and the "neutral" position (N), and in this position (T), the seedling planting device 4 the transmission clutch is disengaged, and the gap c
However, it remains large enough to shift the spool 19 to the wheel lowering position (d), and is configured so that the seedling planting operation is stopped and automatic elevation control is performed, and when the aircraft turns, the following used for.

That is, when one stroke of planting travel to the vicinity of the ridge is completed, the lever 41 is first switched from the "auto" position (A) to the "swivel" position (T) to stop the seedling planting device 4. Next, pull up the control handle 5 slightly to tilt the aircraft slightly forward and downward. Then, the front part of the sensor float 6 is pressed against the field surface S, the ground contact pressure increases, and wheel lowering control is activated. As a result, the machine body is slightly raised, the seedling planting device 4 is floated from the field surface S, and the rear portions of the sensor float 6 and rear grounding floats 7, 7 are also slightly raised from the field surface S. Here, the control handle 5 is kept at a constant height and the aircraft is made to make a U-turn while maintaining the control neutral state. In this way, the direction of the aircraft can be changed without knocking over the already planted seedlings at the rear of the float or sweeping away much of the mud from the field S on the side of the float. After turning, the lever 41 is returned to the "automatic" position (A) and the next stage of planting is started.

Further, it is preferable that the automatic wheel raising/lowering control described above is not activated when the main clutch is disengaged to stop the aircraft.

That is, in general, in a walk-behind rice transplanter, when the rice transplanter moves forward in a field, the reverse torque caused by the forward rotation of the wheels 9 acts to tilt the machine body backward, and the rear part of the machine body tends to sink. Therefore, the weight balance of the machine is designed so that it leans forward when the machine is stopped, thereby absorbing the backward tilting effect caused by the reverse torque of the wheels and keeping the machine approximately horizontal in the front and back, allowing it to run stably in the field. Therefore, in the middle of planting, in order to transfer the seedlings from the spare seedling stand 51 at the front of the machine to the seedling stand 10, or to replenish the seedlings to the spare seedling stand 51, the main clutch must be disconnected to stop the machine. When the vehicle stops and releases the control handle 5, the vehicle tilts forward and downward due to the disappearance of the wheel reverse torque, which is detected by the sensor float 6, and wheel lowering control is performed.
This would cause the aircraft to rise significantly. However, there is no problem because the hydraulic mechanism does not work when the engine 2 is stopped and the machine is stopped, but generally the engine is not stopped each time the machine is stopped during work such as replenishing seedlings, so the above problem occurs.

Therefore, it is necessary to check the elevation control when the main clutch is disengaged to stop the aircraft, and the structure for this purpose is incorporated into the elevation control mechanism as follows.

The upper piece 33c of the T-shaped link 33 has an inner part of a release wire 48 which is installed across a main clutch lever 46 provided on the operating handle 5 and a main clutch operating arm 47 provided on the upper surface of the transmission case 3. A wire 48a passes through the inner wire 48a, and a sleeve 49 that can be freely expanded and contracted with a screw is fitted around the front end of the inner wire 48a. Then, the main clutch lever 46 is switched to the clutch release position (OFF), and the wire 4
When the sleeve 8a is pulled backward, the sleeve 4
The rear end of the T-shaped link 33 and the downward arm 23 integrated therewith are prevented from being rotated further clockwise by directly contacting the front surface of the upward piece 33c in the control neutral position. The length of the sleeve 49 is adjusted so that.

In this way, when the main clutch is disengaged to stop the machine for replenishing seedlings in the field, even if the machine falls forward and the ground contact pressure of the sensor float 6 increases, the spool 19 will move to the wheel lowered position ( d) will no longer be switched to. During work, the machine may suddenly fall into a deep part of the tiller G, causing the machine to lean forward significantly, causing the operator to panic and disengage the main clutch to stop the machine. Therefore, from the state in which the T-shaped link 33 is rotated clockwise first, the T-shaped link 3 is rotated by the contact between the sleeve 49 and the upwardly facing piece 33c.
3 is forcibly rotated clockwise to push the sensor float 6 into the surface S. At this time, the first and second sensor rods 36 and 37, which are subjected to a strong compressive force, are compressed by the interposed spring 38. The deformation shortens it and prevents buckling and breakage.

In addition, when the main clutch is disengaged and the aircraft is stopped, the aircraft may be lower than the ridge, making it difficult to replenish new seedlings. '' position (U), and pull the push/pull link 24 directly rearward using the wire 42a. Then, the downward arm 23, which is prevented from rotating clockwise as described above,
On the other hand, the push/pull link 24 is flexibly linked via the front and rear elongated holes 28 and the pin 26.
By operating the lever 41 a little forcefully, the link 24 can be shifted backward against the spring 34 to lower the wheels. When the aircraft has risen to an appropriate height, the lever 41 can be moved to the "neutral" position (N) or "Auto"
Just switch to position (A).

In addition, the reference numeral 50 in FIG. 3 is in order to prevent the push/pull link 24 from moving forward by coming into contact with the downwardly facing piece 33a of the T-shaped link 33 before the spool 19 reaches the stroke end on the wheel upward side. It is a stopper connected to the bracket 21, and even if the front end of the sensor float 6 unexpectedly moves forward and lowers the float 6 while being inserted into the rice field S, this external force will be applied to the spool. The control valve 18 is protected.

[Brief explanation of drawings]

The drawings show an embodiment of the wheel elevation control device for a walking rice transplanter according to the present invention, in which FIG. 1 is an overall side view of the rice transplanter, FIG. 2 is an overall plan view of the rice transplanter, and FIG. 3 is a wheel elevation control device. 4 is a plan view of the control device, FIG. 5 is a perspective view of the control device, FIG. 6 is a schematic perspective view of the wheel suspension structure, FIG. 7 is a front view of the sensor rod, and FIG. 8 is a side view of the device. 3 is a sectional view taken along the line 3, FIG. 9 is a cross-sectional plan view of the link fulcrum portion of the control device, and FIG. 10 is a perspective view of the lever operation portion. 4...Seedling planting device, 6...Grounding float, 9...
... Propulsion wheel, 18 ... Control valve, 19 ... Spool, 31 ... Spool biasing spring, 38 ... Elastic flexibility spring.

Claims (1)

[Claims] 1 A propulsion wheel 9 is attached to the body to which the seedling planting device 4 is connected.
The ground float 6 is attached to be able to be raised and lowered by hydraulic drive, and the ground float 6 installed at the bottom of the fuselage so as to be movable up and down is linked to a hydraulic control valve 18 for raising and lowering the wheels, and the spool 19 of the control valve 18 is compressed in the direction of the wheel raising operation. A biasing spring 31 is provided, and when the grounding float 6 is displaced upward against the spring 31 as the grounding pressure increases, the control valve 18 is switched to the wheel lowering side, and the grounding float 6 causes the grounding pressure to decrease. The control valve 18 is configured to be switched to the wheel rising side when the ground float 6 is displaced downward due to In a wheel lift control device for a walk-behind rice transplanter, which is equipped with a spring 38 that elastically maintains this flexibility, the spring 31 for biasing the spool is pressurized. In addition to being configured to be adjustable, the elastic accommodating spring 38 is assembled with an initial pressure applied, and this initial pressure is used as the biasing force acting on the spool 19 when the spool biasing spring 31 is adjusted to the maximum strength. A wheel lift control device for a walk-behind rice transplanter that is set equal to or larger than this.