JP3141142B2 - Rice transplanter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice transplanter capable of rolling control of a planting portion with respect to a traveling machine body.

[0002]

2. Description of the Related Art Conventionally, as a seed rice transplanter, a planting section having a plurality of planting claws and a seedling mounting table on a traveling machine body is swung in the machine body width direction via a rolling shaft extending in the machine longitudinal direction. Provide a hydraulic circuit having a hydraulic cylinder and a direction switching valve that controls the relative angle of the planting portion with respect to the vehicle body when the relative angle between the planting portion and the vehicle body fluctuates. The switching control of the direction switching valve is performed based on an output from a controller or the like associated with the change in the relative angle, and the planting portion is controlled to be rolled with respect to the body while supplying and discharging pressure oil to and from the hydraulic cylinder. There has already been proposed an arrangement in which the planting portion is always kept in a horizontal position so that the planting depth of the seedlings by the planting claws is kept constant. In the above rice transplanter, when the direction switching valve is switched to the neutral position, the planting portion is fixed to the machine body at a rolling control position.

[0003]

In the case where the planting operation of the seedlings is performed while performing the automatic rolling control of the planting section with the rice transplanter as described above, the control components such as the above-mentioned components are used. When the directional control valve, the controller or the like breaks down, the directional control valve is automatically returned to the neutral position, and the planting section is fixed to the machine side at the rolling control position. It is difficult to continue the attachment work. That is, due to a failure of the rolling control component, for example, the planting section is locked in a state where the predetermined angle rolling control is performed on the machine body,
When the seedling planting operation is continued in such a state, the seedling planting depths on the left and right sides of the planting part are different, and
Even if the planting section is locked in a horizontal state, even when the wheels provided on the body lean on the slope or unevenness of the paddy field cultivator and the body tilts, the planting section follows the machine body and the planting section follows. Because it is rocked, the planting depth of the seedlings on the left and right sides of the planted portion becomes uneven, and in extreme cases, one of the left and right sides of the planted portion becomes a floating seedling. A problem arises.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to solve the problem that a failure has occurred in a component of a hydraulic circuit that performs rolling control of a planting part during a planting operation. At this time, the fixed state of the planting portion at the rolling control position with respect to the airframe can be forcibly released, so that the seedling planting depth on the left and right sides of the planting portion is not uniform or floating seedlings are generated. An object of the present invention is to provide a rice transplanter that can continue the planting operation of seedlings without inviting rice.

[0005]

The rice transplanter according to the present invention comprises:
It has a planting part that can roll around a rolling axis along the longitudinal direction of the body, a piston and a pair of oil chambers arranged on both sides of the piston, and controls the relative angle between the planting part and the body. A hydraulic switching cylinder, and a direction switching valve interposed between a pair of oil passages communicating with the pair of oil chambers, and controlling supply and discharge of pressurized oil to and from these oil passages to control rolling of the planted portion. A rice transplanter, wherein the direction switching valve is configured to fix the planting portion at a position controlled by rolling when the supply and discharge of pressure oil is stopped, a bypass passage that short-circuits the pair of oil chambers, An on-off valve that closes the bypass passage and opens the bypass passage when rolling control of the planted portion cannot be performed due to a failure.

[0006]

In the above-described operation of planting seedlings with the rice transplanter, when there is no abnormality in the rolling control components such as the direction switching valve and the controller, the on / off valve interposed in the bypass passage is closed. In this state, the aircraft is driven in a paddy field. If the relative angle between the airframe and the planting portion fluctuates, for example, when the airframe rides on the slope, unevenness, or the like of the paddy field cultivator, the direction switching valve is changed according to the change in the relative angle. Is switched, pressure oil is selectively supplied to and discharged from both oil chambers of the hydraulic cylinder, and the piston is moved left and right.Accordingly, a planting portion is provided around the rolling shaft with respect to the machine body. Under the rolling control, the seedlings are planted at a certain planting depth while the planting part is kept in a horizontal posture.

Further, as described above, when a seedling is being planted while performing rolling control on the planting portion, when a failure occurs in a component of the rolling control, for example, the directional control valve or the like. The directional control valve is automatically returned to the neutral position at the end of the rolling control, and the supply and discharge of the pressure oil from the directional control valve to both oil chambers of the hydraulic cylinder is stopped. The piston of the hydraulic cylinder is locked at the rolling control position, and the planting section is fixed to the machine body at the rolling control position. In such a case, the opening / closing valve is opened. Then, with the opening operation of the on-off valve, the two oil chambers provided on both sides of the piston of the hydraulic cylinder are communicated via the bypass passage, and the pressure between the bypass passage and the two oil chambers is increased. Oil circulation is possible, that is,
Since the reciprocation of the piston is free, the fixation of the planting portion to the body at the rolling control position is released, and the planting portion can swing freely. For this reason, when the body enters the slope of rice paddy, the unevenness, etc., and the body tilts, it is possible to prevent the planting portion from following the body and swinging, and the right and left sides of the planting portion can be prevented. The planting operation of the seedlings can be continued without causing unevenness in the planting depth of the seedlings on both sides, and without causing the occurrence of floating seedlings.

[0008]

A rice transplanter shown in FIGS. 7 and 8 supports a front wheel 2 and a rear wheel 3 at front and rear and left and right positions on a lower side of a traveling body 1 and a driver seat on an upper side of the body 1. The planting portion 6 is supported on the rear side of the body 1 via a parallel link mechanism 5 including a top link 51 and a pair of left and right lower links 52, 52 so as to be vertically movable.

The planting section 6 includes a central transmission case 61 to which power is transmitted from the body 1 side, and a central transmission case 61.
A plurality of planting transmission cases 62 connected to the left and right sides via transmission pipes, a plurality of rotary planting claws 63 and a seedling mounting 64 rotatably supported by the planting transmission case 62, With the rotation of the planting claws 63, the seedlings on the seedling mounting table 64 are sequentially taken out and planted on the paddy soil surface. As shown in FIG. 2, the seedling mounting table 64 of the planting section 6 is provided with a lower rail 65 extending in the machine body width direction at a lower side thereof. And a guide part 66 protruded from the slidably inserted therein, and an upper rail 67 extending in parallel with the lower rail 65 is provided on an upper side of the seedling mounting table 64. 64 on the back side,
The upper rail 67 is slidably inserted into each roller portion 69 attached to the upper end of each column 68 extending upward from each of the transmission cases 61 and 62, and the upper rail 67 slides on the roller portion 69. The lower rail 65 with respect to the guide portion 66
By sliding the seedling mounting 64, the entire seedling mounting 64 is reciprocated in the machine body width direction, and while the seedling mounting 64 is reciprocated, the seedlings mounted on the seedling mounting 64 are planted. The nails 66 are sequentially taken out and planted on the paddy soil surface.

[0010] Also, at the lower central position of the planting portion 6,
As shown in FIG. 8, the front part has a wide flat part 71,
A main float 7 having a narrow ground contact portion 72 on the rear side is provided, and a wide flat portion is also provided on the left and right sides of the main float 7 below the planting portion 6 on the front side. Left and right side floats 8, 8 having a narrow ground contact portion 82 on the rear side, respectively, are provided, and the main float 7 and each side float 8 are used to form the planting portion 6.
And share the load of each,
The leveling portions 71 and 81 provided on the floats 7 and 8 level the paddy soil surface on the front side of the planting by the planting claws 63, and the leveling portions 71 and 81 and the grounding portions. 72,8
The front and rear wheels 2, which are formed on the soil surface when the aircraft is running
The third wheel mark is erased.

Further, the planting section 6 is supported so as to be capable of rolling in the left-right direction with respect to the machine body 1, that is, as shown in FIGS. 2 and 3, the machine body 1 and the planting section are supported. 6, a box-shaped pivot portion 9 is interposed therebetween, and each link 51, 5 constituting the parallel link mechanism 5 is provided on the pivot portion 9.
2 and a boss 91 provided on the pivot 9
A plurality of bearing members 92 such as ball bearings and collars
The rolling shaft 1 protrudes forward from the fixing plate 61a fixed to the central transmission case 61 side through the
0 is rotatably supported, and the entire planting section 6 can be rolled in the left-right direction with respect to the body 1 around the rolling shaft 10.

The support 68 provided on the planting section 6
A tilt sensor 11 for detecting a tilt angle of the planting section 6
And an angular velocity sensor 12 for detecting the inclination angular velocity of the planting section 6, respectively, and a relative angle of the planting section 6 with respect to the machine body 1 is provided between the body 1 and the planting section 6. A hydraulic circuit 13 for rolling control for adjustment is provided. The hydraulic circuit 13 is provided with a hydraulic cylinder 14 interposed between the body 1 and the planting section 6 and a detection of the sensors 11 and 12. Switching control based on the result,
An electromagnetic directional switching valve 15 for selectively supplying and discharging pressure oil to and from the hydraulic cylinder 14 is provided.

More specifically, as shown in FIG. 1, the hydraulic cylinder 14 constituting the hydraulic circuit 13 has two oil chambers (hereinafter referred to as working chambers) 14b, 14c, and the working chambers 14b, 14c are provided on both sides of the piston 14a.
Rods 14d and 14e projecting from the outside to the outside
The direction switching valve 15 is provided at three positions 4 for selectively supplying and discharging pressure oil to both working chambers 14b and 14c of the hydraulic cylinder 14 via pipes A and B serving as oil passages.
A port switching type electromagnetic type is used. A hydraulic pump 17 rotated by an engine 16 is connected to the primary side of the direction switching valve 15 via a pipe C. In the same figure, the direction switching valve 15 and the hydraulic pump 17
A relief valve 18 is interposed in the middle of a pipe C connecting the directional control valve 15 and the hydraulic cylinder 14.
Pipes A, B connecting the two working chambers 14b, 14c
The check valve 19 and the throttle valve 20 are interposed in parallel.

The parallel link mechanism 5 and the planting section 6
A column-shaped support 9 is provided on the upper side of the pivotal support 9 interposed therebetween.
3 and a support rod 94 extending upward is attached to the column 93. A bracket 95 having a substantially U shape is attached to the upper side of the support rod 94, and the hydraulic circuit 13 is attached to the bracket 95. Is fixed in the machine body width direction. As shown in FIG. 4, the hydraulic cylinder 14 has the piston rods 14d, 14e protruding from both left and right sides thereof.
Are connected via fixed joints 14f, 14f respectively to fixed plates 68b attached to both sides in the longitudinal direction of connecting rods 68a provided between the columns 68 of the planting section 6, respectively. By supplying and discharging the pressure oil into and out of the piston 14, the piston rods 14d and 14e are advanced and retracted, so that the planting portion 6 is connected via the connecting rod 68a and the columns 68.
Can be rolled in the left-right direction about the rolling shaft 10.

As described above, when the rolling control of the planting section 6 is performed on the body 1, as shown in FIG. 5, the tilt sensor 11 and the tilt sensor 11 are provided on the input side of the controller 21. An angular velocity sensor 12, an automatic switch 22 for automatically controlling the rolling of the planting section 6, and an angle setting dial 2 for setting the angle of the angular velocity sensor 12
3 and a manual switch 24 for manually performing rolling control of the planting section 6, and an output side of the controller 21 is connected to the electromagnetic directional switching valve 15 provided in the hydraulic circuit 13. The hydraulic cylinder 14 is connected to the output side of the direction switching valve 15.

When the automatic switch 22 is turned on to perform automatic rolling control of the planting section 6 with respect to the body 1, the inclination angle of the planting section 6 detected by the sensors 11 and 12 is determined. The direction switching valve 15 is switched to one of the left and right switching positions shown in FIG. 1 by an output signal output from the controller 21 based on the angular velocity and the angular velocity. The piston 14a is selectively supplied / discharged from the direction switching valve 15 to the two working chambers 14b, 14c of the hydraulic cylinder 14 via the respective pipes A, B, whereby the piston 14a is moved left and right, and the respective piston rods 14d, 14e. , The rolling control of the planting section 6 with respect to the body 1 is performed.
When the direction switching valve 15 is switched to the neutral position at the center position in the figure, the supply and discharge of the pressure oil to both working chambers 14b and 14c of the hydraulic cylinder 14 are stopped, and accordingly, the planting section is stopped. 6 is locked to the machine body 1 at the rolling control position.

As described above, by controlling the rolling of the planting section 6 via the hydraulic circuit 13 with the output from the controller 21 based on the detection results of the sensors 11 and 12, the planting is performed. The posture of the attachment section 6 can be controlled accurately and quickly. Therefore, the planting is performed by causing the body 1 to run at high speed and rotating the rotary planting section 63 provided in the planting section 6 at high speed. It is configured such that high-speed planting by the attachment section 6 is enabled.

The tilt sensor 11 includes, for example, a movable coil with a pendulum, a bridge circuit, and a light emitting and receiving element in a casing.
A change in the amount of light received by the light receiving element is detected by the swing of the pendulum due to the inclination of the sensor, and a current value output from the movable coil is detected by a change in balance of the bridge circuit caused by the change in the amount of light received. Is used.

Further, as the angular velocity sensor 12,
For example, a tuning fork type including a piezoelectric bimorph drive element and a detection element and utilizing the generation of a voltage due to the deflection of the drive element due to the inclination of the planting section 6, or a thin disk inside the casing A piezo-plastic film is arranged as a vibrator, and the vertical and horizontal components of the acceleration direction are separated by this vibrator, and the angular velocity is calculated by integrating the acceleration. .

In the rice transplanter described above, both working chambers 14b, formed in the hydraulic cylinder 14, are provided on the secondary side of the direction switching valve 15 in the hydraulic circuit 13.
A bypass passage 25 for short-circuiting between the 14c is provided.
An on-off valve 26 that opens when rolling control is disabled is provided in the bypass passage 25.

Specifically, as clarified in FIG.
The pipes A and B are communicated with the hydraulic cylinder 14 in the middle of the pipes A and B connecting the direction switching valve 15 and the working chambers 14 b and 14 c on both sides of the hydraulic cylinder 14. The bypass passage 25 is provided, and the on-off valve 26 that can be manually operated is interposed in the bypass passage 25.

Next, the operation of the rice transplanter configured as described above will be described. First, when planting a seedling while performing automatic rolling control of the planting unit 6 with respect to the machine body 1, in a state where the on-off valve 26 provided in the bypass passage 25 is closed, The airframe 1 is run in a paddy field. Then, when the body 1 climbs on the slope or unevenness of the paddy field cultivator and the relative angle between the body 1 and the planting section 6 fluctuates, the inclination and angular velocity sensors 11 and 12 The inclination angle and the angular velocity of the planting section 6 are detected, respectively, and the direction switching valve 15 is switched to one of the left and right switching positions shown in FIG. 1 by an output signal from the controller 21 based on the detection result. Accordingly, the pressure oil from the hydraulic pump 17 is selectively supplied and discharged from the direction switching valve 15 to both working chambers 14b and 14c of the hydraulic cylinder 14 via the pipes A and B, and the piston 14a Is moved right and left, and the piston rods 14d and 14e move forward and backward with this, so that the planting portion 6 is controlled to be rolled around the rolling shaft 10 with respect to the body 1 side, and the planting is performed. 6 seedlings are planted in a constant planting depth while being held in a horizontal posture.

Further, as described above, in the case where the planting operation of the seedling is performed while controlling the rolling of the planting section 6,
When a failure occurs in the direction switching valve 15 of the hydraulic circuit 13, the controller 21, or the like, the direction switching valve 15 is automatically returned to the neutral position in the center of FIG. Since the supply and discharge of the pressure oil to both working chambers 14b and 14c of the hydraulic cylinder 14 is stopped, if a failure occurs in this state, the piston 14a of the hydraulic cylinder 14 is locked at the rolling control position, and the planting is performed. The unit 6 is fixed to the body 1 at a rolling control position. In such a case, the on-off valve 2
6 is opened. Then, with the opening operation of the on-off valve 26, both working chambers 14 of the hydraulic cylinder 14
b, 14c are communicated through the bypass passage 25,
The circulation of the pressure oil between the bypass passage 25 and the two working chambers 14b and 14c is possible, that is, the reciprocation of the piston 14a is free, so that the rolling of the planting portion 6 with respect to the body 1 is performed. The locked state at the control position is released, and the planting section 6 can freely swing. Therefore, even if the airframe 1 leans on the slope or unevenness of the paddy field, the planting section 6 is prevented from swinging following the airframe 1 and the planting is prevented. The seedling planting operation can be continued without causing the seedling planting depths on the left and right sides of the attachment portion 6 to be uneven or causing the occurrence of floating seedlings.

By the way, as described above, the hydraulic circuit 1
When the directional switching valve 15 or the controller 21 of 3, for example, fails, the locking state of the planting section 6 with respect to the machine body 1 is released by the opening operation of the on-off valve 26 to continue the seedling planting operation. Since the planting portion 6 is free to swing with respect to the machine body 1 side, a weight change in the machine body width direction occurs with the reciprocating left and right movement of the seedling table 64 provided in the planting portion 6, The planting portion 6 may be inclined with respect to the machine body 1 around the rolling shaft 10 due to the weight change, and the planting depth of the seedling by the planting portion 6 may become uneven. The problem is avoided by providing the following structure.

That is, as clarified in FIGS. 2 and 3,
A support plate 27 extending in the machine body width direction is attached to an upper side of the bracket 95 that holds the hydraulic cylinder 14,
Rolling correction springs 29, 29 are respectively stretched between both ends of the support plate 27 and the connecting tools 28, 28 attached to both sides in the width direction of the seedling mounting table 64, respectively. Thus, the seedling mounting table 64 is biased so as to be constantly pulled toward the center in the machine width direction. A plurality of adjustment holes 27a are formed in the support plate 27 in the width direction, and the tension of each of the correction springs 29 is adjusted by selecting each of the adjustment holes 27a and changing the mounting position with respect to the bracket 95. Thus, the pulling force on the seedling mounting table 64 can be changed.

A box-shaped bracket 30 is protruded from a surface of the pivot portion 9 near the rolling shaft supporting boss 91 and a surface facing the fixing plate 61a to which the rolling shaft 10 is fixed. A spring receiving rod 31 extending in the machine body width direction is inserted into and supported by the bracket 30, and a projecting rod 31a is protruded from the center of the spring receiving rod 31 in the longitudinal direction. At the time of insertion support, the protruding rod 31a is inserted into the insertion hole 61b provided on the upper side of the fixing plate 61a via the arc-shaped long hole 30a provided in the bracket 30.
Rolling regulating springs 32, 32 are inserted into both sides of the spring receiving rod 31 in the width direction, respectively.
By fixing the outer ends in the length direction 2 with fixtures 33, 33 such as spring washers and nuts, the swing of the seedling mounting table 64 about the rolling shaft 10 by the respective regulating springs 32 is performed. We will regulate it.

The rolling shaft 10 of the seedling mounting table 64 is formed by the correction springs 29 and the restriction springs 32.
When the lock of the planting portion 6 to the machine body 1 is released as described above, the planting portion 6 moves the rolling shaft 10 with the reciprocating movement of the seedling mounting table 64 left and right. The planting part 6 is inclined with respect to the body 1 at the center.
This prevents the planting depth of seedlings from becoming uneven.

In the embodiment shown in the figure, while the vehicle is running at a high speed, the output from the controller 21 based on the detection results of the sensors 11 and 12 is used to roll the planting section 6 through the hydraulic circuit 13. In the case of performing control, it is possible to prevent the leveling portion 81 of the side floats 8, 8 from pushing the soil of the paddy field to the side or to deteriorate the planting posture of the planted seedlings planted on the adjacent strip by the water flow. To prevent this, each of the side floats 8, 8 disposed on both sides in the width direction below the planting portion 6 is raised to a grounding position where each flat portion 81 is grounded and a non-grounding position where each flat portion 81 is not grounded. Adjustable support.

That is, as clarified in FIG. 6, the upper and lower portions of the side floats 8 arranged on both sides in the width direction at the lower side of the planting portion 6, ie, at the front and rear portions, that is, the respective side floats 8 on the upper side of the leveling portion 81 and the grounding portion 82,
First and second protruding pieces 34 and 35 are provided so as to protrude, respectively, and the second protruding piece 35 is pivotally supported by a support arm 36 supported by the planting transmission case 62. An adjustment arm 37 extending upward is pivotally pivotally supported, and an operation wire 38 extending from an operation lever provided near the driver's seat 4 is connected to the upper end of the adjustment arm 37, and operated by operating the lever. By tensioning and relaxing the wire 38, the whole of the side float 8 is vertically swung about a pivotal portion between the second projecting piece 35 and the support arm 36, whereby the flat portion of the side float 8 is flattened. The height 81 is adjusted over a contact position (solid line position in the figure) with respect to the soil surface D of the paddy field and a non-contact position (virtual line position in the figure). As described above, since each of the side floats 8 adjusts the height of each of the leveling portions 81 to the grounded position and the non-grounded position, the leveling of the leveled portions 81 is performed in order to smoothly perform the height adjustment. The rear side of each of the grounding portions 82 continuous with the portion 81 is the second protruding piece 35 and the support arm 3.
5, the entire length is shortened by the length of the main float 7. In FIG. 6, the adjusting arm 37 has a long hole 37a extending vertically.
A regulating pin 37b is provided on the front side of the planting transmission case 62 to protrude into the elongated hole 37a, and the adjusting arm 37 is operated by the pin 38b and the elongated hole 37a to operate the wire 38. In the meantime, on the front side of the planting transmission case 62,
A wire holder 39 for holding the wire 38 near the adjusting arm 37 is attached.

When the machine body 1 is driven at a high speed and the high-speed planting work is performed while rotating the respective planting claws 63 of the planting section 6 at a high speed, the wide flat portions 81 of the side floats 8 are used. As shown by the imaginary line in FIG. 1, the paddy soil is raised by the flat portions 81 of the side floats 8 so as to be separated from the paddy soil surface D to an upper non-contact position. Of the planting seedlings planted on the adjacent streak is eliminated by extruding the plants to the side or by eliminating high-speed running of the flat portions 81 due to the generation of waves or rapid water flow. To prevent it. At the time of high-speed planting as described above, the inclination sensor 11 and the angular velocity sensor 1
2 through the hydraulic circuit 13 based on the output from the controller 21 based on the detection result from
Is accurately and quickly controlled, and the horizontal control correspondence is significantly improved, and the load shared by the side floats 8 on the planting section 6 can be reduced to almost zero. Even if the leveling section 81 is retracted upward from the soil surface D, the planting section 6
It has no effect on the seedling planting work.

As described above, when the planting operation of the seedling is performed while controlling the rolling of the planting section 6,
Despite the failure of the direction switching valve 15 of the hydraulic circuit 13 and the controller 21, the on-off valve 26
When the locking operation of the planting unit 6 with respect to the machine body 1 is released by the opening operation of the plant 1 and the seedling planting operation is continued, the wide flat portion 81 of each of the side floats 8 is indicated by a solid line in FIG. Then, it is lowered to the side of the ground contact position where it touches the soil surface D. In this case, even if the seedling table 64 reciprocates left and right with the release of the lock of the planting section 6 to the machine body 1, the weight of the seedling table 64 is lowered to the ground contact position. , The inclination of the planting part 6 around the rolling axis 10 is prevented, and the planting depth of the seedling by the planting part 6 is reliably prevented from becoming uneven. It is done.

When adjusting the height of the flat portion 81 of the side float 8 between the contact position and the non-contact position, the tension and relaxation of the operation wire 38 may be performed by a motor or the like. Also, without using the operation wire 38 as described above, the flat portion 81 is connected to the grounding position between the adjusting arm 37 provided on the flat portion 81 side and the planting transmission case 62. It is also possible to provide a lock mechanism for manually locking to the non-contact position, and to manually position the flat portion 81 between the contact position and the non-contact position via the lock mechanism.

In the above embodiment, the on-off valve 26 is manually opened and closed. However, a system capable of detecting a failure of the directional control valve 15 and a failure of the controller 21 is provided by detecting these failures. You may make it open automatically.

[0034]

As described above, according to the present invention, the opening / closing valve is opened when, for example, the directional control valve fails during the planting operation of the seedling and the rolling control of the planting portion cannot be performed. Then, the pair of oil chambers of the hydraulic cylinder communicate with each other via the bypass passage, and the fixed state of the planting part at the rolling control position can be forcibly released. When the aircraft leans into the aircraft, the planting section can follow the aircraft and prevent it from swinging, and the seedling planting depth on the left and right sides of the planting section becomes uneven, The planting operation of the seedlings can be continued without causing the occurrence of floating seedlings.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a hydraulic circuit which is a main part of a rice transplanter according to the present invention.

FIG. 2 is an enlarged side view showing a planting section of the rice transplanter.

FIG. 3 is an exploded perspective view showing a main part of the planting section.

FIG. 4 is a partially omitted plan view showing a mounting portion of a hydraulic cylinder constituting a hydraulic circuit.

FIG. 5 is a control block diagram of the hydraulic circuit.

FIG. 6 is a side view showing a float portion of the planting section.

FIG. 7 is a side view showing the entire structure of the rice transplanter.

FIG. 8 is a plan view of the rice transplanter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 6 Planting part 10 Rolling shaft 13 Hydraulic circuit 14 Hydraulic cylinder 14a Piston 14b, 14c Working chamber 15 Direction switching valve 25 Bypass passage 26 Opening / closing valve

Claims (1)

(57) [Claims] 1. A planting portion which can be rolled about a rolling axis along a longitudinal direction of a body, a piston, and a pair of oil chambers arranged on both sides of the piston, wherein the planting portion and the body are provided. A hydraulic cylinder for controlling the relative angle of
Interposed between a pair of oil passages communicating with the pair of oil chambers,
A direction switching valve for controlling the rolling of the planted portion by switching the supply and discharge of pressure oil to and from these oil passages, and when the direction switching valve stops supplying and discharging pressure oil, the planting portion is controlled to be rolled. In a rice transplanter adapted to be fixed at a position, a bypass passage that short-circuits between the pair of oil chambers, and the bypass passage that closes the bypass passage and prevents rolling control of the planting portion due to a failure. A rice transplanter, comprising: an on-off valve for opening a valve.