JPH0889035A - Apparatus for lifting and lowering machine body in paddy field working vehicle - Google Patents

Abstract

PURPOSE: To keep sensing load of a float nearly constant by oscillating an oscillating member so as not to largely change energizing force of a spring regardless of movement of an operating arm of a hydraulic pressure change over valve to raising position and lowering position. CONSTITUTION: Soil pressure which soil pressure sensing body senses acts as movement of an operating arm 10a provided through hydraulic members 22, 23, 26 and 96 in hydraulic pressure to raising position direction. One end of a spring 93 energized to the lowering position of a hydraulic pressure change over valve 10 is connected to the operating arm 10a and an oscillating member 71 is connected to the other end of the spring 70. The oscillating member is oscillated so as not to largely change energizing forcer of the spring 93 regardless transfer of the operating arm 10a by stretching and providing the oscillating member 71 by other spring 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paddy field work vehicle such as a walk-behind rice transplanter and, more particularly, to a machine body lifting device for sensing earth pressure from a rice field and controlling the machine body height.

[0002]

2. Description of the Related Art As a conventional body lifting device for a paddy work vehicle, there is, for example, the one disclosed in Japanese Utility Model Publication No. 4-133112. The body lifting device shown in this publication is shown in FIG.
As shown in FIG. 3, the planting clutch lever 2 connected to the planting clutch 1 and the traveling clutch lever 5 connected to the traveling clutch 3 are provided, and a paddy wheel is provided in a chain case rotatably supported by the machine body. At the same time, this chain case is connected to a hydraulic cylinder for adjusting the height of the machine body, and a hydraulic pressure switching valve 10 communicating with this hydraulic cylinder is further connected to a machine body height detection mechanism to switch the hydraulic pressure switching valve 10 to change the machine body height. The float height detecting mechanism detects the earth pressure on the paddy field to detect the height of the fuselage, and the shaft 81 penetrating the mission case 32. And a sensing rod 12 whose left and right bosses are rotatably supported, and a protrusion 12 protruding from the center of the left and right bosses of the sensing rod 12. It is linked inserted through the connecting plate 82 the tip of which is fixed to the float.

Accordingly, the vertical movement of the float is transmitted to the sensing rod 12 as a rotation around the shaft 81, and the sensing rod 12 is transmitted to the shaft 81 as a rotation only in the vertical direction due to the both-end support structure. To be done. An arm 19 is rotatably supported on the left side end of the body of the shaft 81. Further, the first plate 23 and the first plate 23 are provided between the arm 19 and the left boss portion of the sensing rod 12 supported by the shaft 81. Each second plate 26 is rotatably supported.

One end of a rod 22 movably penetrating the elongated hole 21a of the connecting plate 21 is fixed to the first plate 23, and the other end of the rod 22 is fixed to the hydraulic switching valve 10. It is connected to the operation arm 10a. The hydraulic switching valve 10 communicates with the hydraulic cylinder and the hydraulic pump, and switches the hydraulic switching valve 10 between the raised position, the lowered position, and the neutral position by the turning position of the operation arm 10a. Also,
A return spring 93 is stretched on the operation arm 10a, and the return spring 93 is used for the hydraulic switching valve 1.
0 is urged toward the lower position.

The second plate 26 has a long hole 26.
a, a first lug 26b protruding on one side surface, a second lug 26c protruding on the other side surface, and a spring hook portion 26.
d. A bolt 95 having a tightening nut is screwed into the first lug 26b so that the tip of the bolt 95 comes into contact with the side surface of the first plate 23. Then, by rotating the hydraulic pressure switching valve 10 in the raising direction, the first plate 2 regardless of the position of the second plate 26.
3 is allowed to rotate in the raising direction. Further, the second lug 26c is in contact with the sensing rod 12, and a spring 96 is stretched between the spring hooking portion 26d and the bent portion of the sensing rod 12, so that the second plate 26 and the sensing rod 12 are connected. And are linked via a spring 96 or by contact.

In addition, on either one of the left and right sides of the body,
The operation part 1a of the planting clutch 1 and the planting clutch lever 2 are arranged, and a planting clutch system connecting means for connecting the operation part 1a and the planting clutch lever 2 is arranged. Further, a traveling clutch system coupling means for disposing the operating portion 3a and the traveling clutch lever 5 of the traveling clutch 3 on either the left or right side of the machine body and coupling the operating portion 3a and the traveling clutch lever 5 together. To place. Then, the hydraulic pressure switching valve 10
In addition, while linking the planting clutch system connecting means via a first interchange mechanism, and linking the traveling clutch system connecting means via a second interchange mechanism, on either the left or right side of the machine body, A lower hydraulic pressure adjusting unit 27 that adjusts the relationship between the planting clutch system connecting means and the first interchange mechanism, and an upward hydraulic pressure adjusting unit 29 that adjusts the relationship between the traveling clutch system connecting unit and the second interchange mechanism. I have set up.

The planting clutch system coupling means couples the first arm 14r to the planting lever rod 13 extending from the planting clutch lever 2, and connects the first arm 14r to the lug 14a formed integrally with the first arm 14r. The planting clutch lever 2 is connected to the planting lever rod 13 and the planting clutch 1 is connected to the rod 15 in a configuration of penetrating the rod 15.

The traveling clutch system connecting means fixes the branch plate 17 to the intermediate portion of the rod 16 extending from the traveling clutch lever 5, and connects the arm 19 to the tip end of the branch plate 17. Arm 19
The rod 20 is connected to the bracket 19a.

The first interchange mechanism is the first plate 2
3 and the connecting plate 2 in the lowering side hydraulic pressure adjusting unit 27
The rod 22 penetrating the one long hole 21a and movably connected along the long hole 21a is connected to the operation arm 10a of the hydraulic switching valve 10.

In the second interchange mechanism, the pin 25a is planted in the plate 25 extending from the traveling clutch lever 5 via the raising hydraulic pressure adjusting portion 29, and the long hole 26a into which the pin 25a is fitted is formed. The plate 25 is formed in the second plate 26, and the pin 25a is movably connected along the long hole 26a.

In order to carry out planting work with the walk-behind rice transplanter thus constructed, the traveling clutch lever 5 is operated to the on position to bring the traveling clutch 3 into the connected state, and the planting clutch lever 2 is brought to the on position. Then, the operating portion 1a is operated to bring the planting clutch 1 into the connected state. As a result, the walk-behind rice transplanter is driven by the paddy field vehicle, and the planting rod rotates to carry out planting work. On this occasion,
The pin 25a of the plate 25 which is interlocked with the traveling clutch lever 5 is located at the intermediate portion of the elongated hole 26a of the second plate 26, and the planting clutch lever 2 includes the first arm 14r, the connecting shaft 65 and the second shaft 26a. The rod 22 is located in the middle of the elongated hole 21a of the connecting plate 21 that is connected via the arm 14l. In this state, the tip of the bolt 95 contacts the side surface of the first plate 23 based on the urging force from the return spring 93 of the hydraulic switching valve 10, and the second plate 26 rotates integrally therewith. The first plate 23 and the second plate 26 are not restricted from rotating by the elongated holes 21a and 26a. Therefore, the vertical movement based on the earth pressure sensing of the float is transmitted to the sensing rod 12 as a swing. Then, the hydraulic switching valve 10 is switched between the raised position, the lowered position, and the neutral position so that the airframe has a constant height with respect to the paddy field based on the detection of the earth pressure of the float, and the hydraulic cylinder is operated to move the paddy wheel. It moves up and down and the height of the aircraft is automatically controlled.

[0012]

By the way, a return spring 93 is stretched on the operation arm 10a so as to extend so as to increase the biasing force acting on the float when the hydraulic pressure switching valve 10 is switched to the raised position. Therefore, when the paddy wheel runs on the uneven cultivator and the hydraulic switching valve 10 is switched to the raised position and the aircraft rises, if the paddy is soft, the float that senses earth pressure sinks. Therefore, there is a problem that the planting depth of seedlings cannot be made constant, and it is desired to reduce the sensing load of the float there.

Also, the return spring 9 having a small spring constant.
When 3 is stretched to reduce the float's sensed load, when the paddy wheel runs on a large uneven cultivator,
There is a problem that the response of the airframe to the sway of the float becomes slow and it is impossible to plant seedlings at a certain depth of the paddy field.

The present invention has been made in order to solve the above problems, and the urging force of the spring does not change significantly regardless of the movement of the operating arm of the hydraulic switching valve to the raised position and the lowered position. It is an object of the present invention to provide an airframe lifting device for a paddy field vehicle in which the sensing load of the float is made substantially constant.

[0015]

In order to achieve the above object, therefore, the body lifting device for a paddy field vehicle according to the present invention has a working part and moves up and down relatively to the paddy wheel (7). Aircraft (4) to obtain and earth pressure sensor (1) suspended by this airframe (4) and moving by sensing the earth pressure from the rice field
1), a hydraulic pressure switching valve (10) that is switched to a raised position, a neutral position, and a lowered position in accordance with the movement of the earth pressure sensor, and the hydraulic pressure from the hydraulic pressure switching bubble,
A hydraulic actuator (9) for moving up and down the airframe relative to the paddy wheels,
The hydraulic pressure switching valve (10) has an operation arm (10a) connected to a spool, and an interlocking member that interlocks the operation arm with movement of the operation arm in one of the ascending position and the descending position. (12, 22, 23, 26, 9
6) is connected to the earth pressure sensor via the above-mentioned 6) and is connected to one end of a spring (93) that biases in the other direction, and the other end of this spring is supported by a rocking support. The rocking member is connected to the moving member (71) and moves in a direction in which the biasing force of the spring (93) does not change, regardless of the movement of the operation arm.

Preferably, the operation arm (10a)
Is interlocked with the earth pressure sensor through the interlocking member with respect to the movement in the upward position direction, and is pulled in the downward position direction by the spring (93).

Preferably, another spring (70) is arranged between the swing member and the connecting member (69), and the swing member swings against the biasing force of the other spring. It moves.

More preferably, the connecting member (69)
Is provided with a plurality of connecting portions (69a), and one end of the other spring (70) is connected to any one of these connecting portions.

[0019]

Based on the above structure, the earth pressure sensed by the earth pressure sensor (11) changes the interlocking member (12, 22, 23, 26, 9).
6) It acts as a movement of the operating arm (10a) provided in the hydraulic pressure switching valve (10) in either one of the raised position and the lowered position. Further, one end of a spring (93) for urging the hydraulic pressure switching valve in the other direction with respect to movement in one of the raised position and the lowered position is connected to the operation arm, and the other end of the spring is connected to the operation arm. By connecting the swing member, the operation arm (1
The swinging member (71) is swung so that the urging force of the spring (93) does not change largely regardless of the movement of 0a). At this time, for example, the rocking member is rocked against the biasing force of another spring (70) arranged between the rocking member (71) and the connecting member (69), and The urging force of (93) is not changed significantly.

The reference numerals in the above parentheses are for comparing the drawings and do not limit the structure of the present invention in any way.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

1 to 3 are views showing an embodiment of the present invention. In FIG. 1 to FIG. 3, the same or uniform components as in FIG. . As shown in FIG. 2, the walk-behind rice transplanter P has an engine 31, a mission case 32, a frame 33 and the like in front of the machine body 4, and a handle 36 is extended behind the machine body 4. In addition, the seedling placing table 37 is supported slidably in the left and right directions. Further, a planting rod 38 is arranged at the lower end portion of the seedling placing table 37. Further, below the frame 33, there is a rear swing fulcrum 11.
Float 11 as an earth pressure sensor swingable around a
Is suspended. The float 11 constitutes a body height detection mechanism that detects earth pressure on the rice field and detects the body height. An output shaft 39 is provided so as to project from the left and right ends of the transmission case 32, and chain cases 6 and 6 which are swingable about the output shaft 39 are supported at both ends of the output shaft 39. Paddy wheels 7, 7 are supported at the tips of the chain cases 6, 6.

Between the bracket 41 fixed to the engine 31 and the bumper member 42 fixed to the transmission case 32, a hydraulic cylinder 9 which is a hydraulic actuator for adjusting the height of the machine body is arranged. . The rod 9 a of the hydraulic cylinder 9 has the bracket 41.
And a movable cylinder type that is fixed to the bumper member 42, and is guided by the rod 9a to move the cylinder portion 9b.
Reciprocates up and down. Further, a balance arm 43 is swingably connected to the cylinder portion 9b about a pin 43a, and both ends of the balance arm 43 are connected to the swing chain cases 6 and 6 via rods 45 and 45, respectively. It is connected to the arms 6a, 6a fixed to the base end. In addition, the intermediate portion of the balance arm 43 and the cylinder portion 9
A horizontal control hydraulic cylinder 46 is interposed between the hydraulic cylinder 46 and b, and the cylinder 46 is controlled based on an inclination sensor 47 to move the balance arm 43 to the left and right, thereby causing the left and right paddy wheels 7 and 7 to run counter to each other. Adjust up and down.

Then, as shown in FIG. 2, work (planting) is performed on the guide plate 50 provided on the handle 36 portion.
A clutch lever 2 and a traveling clutch lever 5 are arranged. Further, the left and right side clutch levers 52L and 52R are provided on the left and right grips 36a of the handle 36, respectively.
Is provided. In FIG. 2, reference numeral 53 is a main gear shift lever, and 55 is a reciprocating motion of a screw shaft arranged in the transmission case 32, which is transmitted as a swinging motion via an arm 56, and further via an arm 57. It is an oscillating rotary shaft that transmits as a left-right reciprocating motion of the seedling placing table 37.

The planting clutch lever 2 guided in the right side groove of the guide plate 50 is transmitted through a wire 60a to a left plate 59a which is rotatably supported by a lower portion of the handle 36 through a bracket. There is.
Further, the traveling clutch lever 5 guided in the left groove of the guide plate 50 is a right plate 59b rotatably supported by a lower portion of the handle 36 via a bracket.
To the wire via a wire 60b. The planting lever rod 13 (see FIG. 1) extends from the right plate 59b to the front of the machine body 4 and the left plate 5b.
A rod (see FIG. 3) extends from 9a in front of the machine body 4. Further, the left and right side clutch levers 52L, 52
Wires 61L and 61R extending from R are guided downward through the handle 36, and further, the frame 33
Is led forward along.

As shown in FIG. 1, a connecting shaft 65 extending in the lateral direction of the machine body is rotatably supported in the middle of the front and rear of the machine body 4 through a bracket 62 provided upright on the frame 33. Left and right angle members 66 and 67, which are U-shaped in a plan view, are rotatably supported on the left and right sides of the connecting shaft 65, respectively. Also, one end of a connecting member 69 having a plurality of connecting holes 69a is rotatably supported at the left end of the connecting shaft 65, and the spring 7 is held in the connecting hole 69a.
One end of 0 is locked, and the other end of the spring 70 is rotatably supported.
Is locked to. Further, one end of the return spring 93 is locked in the locking hole 71a, and the other end of the return spring 93 is locked in the operation arm 10a of the hydraulic pressure switching valve 10.

The inner portion 66 of the left angle member 66
The wire 61L extending from the left side clutch lever 52L is connected to a, and the wire 61R extending from the right side clutch lever 52R is connected to the inner piece 67a of the right angle member 67. Further, the connecting shaft 65 has a left angle member 66 and a right angle member 67.
An intermediate angle member 14 in which a left arm 14l and a right arm 14r are integrally formed is rotatably supported between and. A planting lever rod 13 extending from the planting clutch lever 2 is connected to the right arm 14r of the intermediate angle member 14. A rod 72 is connected to the outer side portion 67b of the right angle member 67, and the tip of the rod 72 is connected to the operating portion 73 of the right side clutch. A rod 74 is connected to the outer side portion 66b of the left angle member 66, and the tip of the rod 74 is connected to the operating portion 75 of the left side clutch.

A lug 14a is formed integrally with the right arm 14r. A rod 15 penetrates the lug 14a and a nut 76 is screwed into the tip screw portion 15a. The spring 77 is contracted. The tip portion of the rod 15 is connected to one end of the operating portion 1a of the planting clutch 1, and a spring 80 is stretched on the other end of the operating portion 1a. Further, a connecting plate 21 is connected to the tip of the left arm 14l by bolts and nuts as shown in FIG.
Moreover, the connecting plate 21 has a long hole 21 on the front end side of its rotation.
a is formed. The first plate 23 is fixed to the other end of the elongated hole 21a by penetrating the other end of the rod 22 connected to one end of the operation arm 10a of the hydraulic switching valve 10. The rod 22, the first plate 23, the second plate 26, the spring 96 and the sensing rod 12 form an interlocking member.

Next, the operation will be described.

To perform planting work with the walk-behind rice transplanter P,
The traveling clutch lever 5 is operated to the on position, and the traveling clutch operating portion is operated via the wire 60b extending to the left side of the machine body, the traveling rod, etc. to bring the traveling clutch into the connected state, and the planting clutch lever 2 is moved. The wire 60a extending to the right side of the machine body when operated to the insertion position, the planting lever rod 13, the right arm 14r of the intermediate angle member 14
Then, the operating portion 1a is operated via the rod 15 to bring the planting clutch 1 into the connected state. As a result, the walk-behind rice transplanter P runs while the paddy field wheels 7 are driven, and the planting rod 38 rotates to perform planting work.

At this time, the pin 25a of the plate 25 which is interlocked with the traveling clutch lever 5 is located at the intermediate portion of the elongated hole 26a of the second plate 26, and the connecting member is provided at the intermediate portion of the elongated hole 21a of the connecting plate 21. Since the tip end of the rod 22 constituting the above is located, in this state, even if the rod 22 moves via the operation arm 10a based on the urging force from the return spring 93, the tip end is a long hole. 21a,
The first plate 23 and the second plate
The plate 26 does not rotate. Therefore, the vertical movement based on the earth pressure detection of the float 11 is transmitted as the swing of the sensing rod 12, is transmitted to the second plate 26 via the spring 96, and is then transmitted via the first plate 23 and the rod 22. Operation arm 1 of hydraulic switching valve 10
0a is transmitted. As a result, the hydraulic switching valve 10
Based on the earth pressure detection of the float 11, the airframe 4 is switched to a raised position, a lowered position, and a neutral position so that the aircraft 4 has a constant height with respect to the rice field, and the hydraulic cylinder 9 is operated to vertically move the paddy wheels 7 and 7. Automatically controls the height of the aircraft.

Even if one or both of the traveling clutch lever 5 and the planting clutch lever 2 are operated to the disengaged position, the tip of the rod 22 and the pin 25a are positioned in the middle of the corresponding long holes 21a and 26a, respectively. As described above, the hydraulic switching valve 10 is automatically controlled based on the vertical movement of the float 11 without hindering the free movement of the first plate 23 and the second plate 26.

Next, when turning the walk-behind rice transplanter P that has reached the headland, the planting clutch lever 2 is operated to the fixed position while the traveling clutch lever 5 is held at the on position. Then, the planting clutch 1 is disengaged to stop the rotation of the planting rod 38, and the coupling plate 21 is moved via the planting lever rod 13, the right arm 14r, and the left arm 14l. Long hole 21
The rod 22 is brought into contact with one end of a. In this position, the first plate 23 is prevented from rotating in the lowering direction,
The hydraulic pressure switching valve 10 is not in the lowered position and is in the raising semi-automatic state in which only the raising direction is allowed. In this raising and semi-automatic state, when the operator lifts the handle 36 upward, the gap between the front portion of the float 11 and the machine body 4 becomes narrow, and the sensing rod 12 is rotated clockwise to rotate the spring 9.
6, the second plate 26 and this second plate 26
The first plate 23 is rotated in the same direction via the bolts fixed to the first lug 26b, and the hydraulic pressure switching valve 10 is switched to the raised position. As a result, the cylinder portion 9b of the hydraulic cylinder 9 is raised along the rod 9a, the paddy wheels 7, 7 are lowered, and the body 4 is raised. The swing member 71 is rotated via the return spring 93 as the operation arm 10a is rotated to the raised position, and the spring 70 is pulled as the swing member 71 rotates. . Therefore, the urging force of the return spring 93 that pushes down the float 11 via the hydraulic pressure switching valve 10 does not change. When the machine body 4 rises by a desired amount in this way, the handle 36 is lowered to bring the walk-behind rice transplanter P into a horizontal state. At this time, the rod 22 is in contact with one end of the long hole 21a of the connecting plate 21. Therefore, the first plate 23 is prevented from rotating in the downward (counterclockwise) direction. At this time, the front part of the float 11 hangs down, the sensing rod 12 rotates counterclockwise, and the second plate 26 also rotates in the same direction due to the contact of the second lug 26c. Since the contact between the bolt fixed to the lug 26b of the first plate 23 and the side surface of the first plate 23 is separated and has no effect on the first plate 23, the hydraulic switching valve 10 is held in the neutral position. Then, the machine body 4 is fixed in the raised position.

Further, when seedlings are supplied to the seedling placing table 37 of the walk type rice transplanter P, the planting clutch lever 2 is set to the on position or the off position, and the traveling clutch lever 5 is operated to the down position. Then, the traveling clutch 3 is disengaged, and the pin 25a planted in the plate 25 at the tip of the rod 16 comes into contact with the other end of the elongated hole 26a, so that the second plate 26 rotates in its upward (clockwise) direction. Movement is regulated. In this position, even if the float 11 raises (clockwise) the sensing rod 12, the second plate 26 is restricted from rotating by the pin 25a, and thus the second plate 26 is rotated by the first plate 23. The hydraulic pressure switching valve 10 is not in the raised position and is in a semi-automatic state in which only the lowering direction is allowed. In this state, the machine body 4 is in the lowered position where a predetermined earth pressure acts on the float 11, and even when the handle body 36 is lifted to raise the machine body 4, the machine body 4 is held in the lowered state.

To stop the height control of the walk-behind rice transplanter P and fix the body 4 for transportation or storage,
The traveling clutch lever 5 is operated to the lowered position and the planting clutch lever 2 is operated to the fixed position. In this state, the traveling clutch 3 and the planting clutch 1 are both in the disengaged state, and the rod 22 is in contact with one end of the elongated hole 21a of the coupling plate 21 to rotate the first plate 23 in the downward (counterclockwise) direction. The pin 25
a contacts the other end of the elongated hole 26a of the second plate 26 to regulate the upward (clockwise) rotation of the second plate 26. Therefore, the hydraulic pressure switching valve 10 is fixed in the neutral position, and the machine body 4 is held at the predetermined height regardless of the movement of the float 11.

When the traveling clutch 5 is in the engaged position and is in the traveling state, or when the traveling clutch 5 is in the lowered position and is in the lowering state of the machine body, when the planting clutch 2 is operated to the raised position,
The operating arm 10a of the hydraulic switching valve 10 is moved to the raised position via the planting lever rod 13, the right arm 14r, the left arm 141, the connecting plate 21 and the rod 22. As a result, the hydraulic cylinder 9 swings the chain case 6, lowers the paddy wheels 7, 7, and raises the machine body 4. At this time, the float 11 hangs down and the sensing rod 1
The second plate 26 is relatively rotated via 2
The bolt fixed to the first lug 26b is separated from the side surface of the first plate 23 without disturbing the movement of the first plate 23 in the raising direction, and the traveling clutch lever 5 is set to the lowered position. Even when the movement of the second plate 26 in the raising direction is restricted, the bolts similarly fixed to the first lugs 26b only separate from the side surfaces, and do not hinder the movement of the first plate 23. .

Therefore, when the planting clutch lever 2 is operated to the raised position, the operation arm 10 of the hydraulic switching valve is operated.
Although a is rotated to the raised position, the swing member 71 is rotated via the return spring 93 with the rotation of the operation arm 10a, and the spring 70 is pulled with the rotation of the swing member 71. Will be done. Therefore, the urging force of the return spring 93 that pushes down the float 11 via the hydraulic pressure switching valve 10 does not change. Further, when the planting clutch lever 2 is operated to the raised position, the machine body 4 is raised with priority, so that the machine body 4 can be raised quickly even in an emergency, and at this time, the planting clutch lever 2 resists the return spring 80. And operate it,
It can be operated lightly and the driving feeling can be improved.

Although the above embodiment has been described with respect to a walk-behind rice transplanter, the present invention is not limited to this, and can be similarly applied to other paddy working machines such as a paddy direct flooding machine.

[0039]

As described above, according to the present invention, the other end of the spring having one end stretched on the operating arm is connected to the swinging member, and the swinging member is concerned with the movement of the operating arm. However, since the spring oscillates in the direction in which the urging force of the spring does not change, the urging force of the spring does not change significantly even if the operation arm moves to the raised position and the lowered position based on the earth pressure sensing of the earth pressure sensor. Therefore, even if the rice field is soft, the float does not sink and the seedlings can be planted at a certain depth of the rice field.

Further, another spring is stretched between the swinging member and the connecting member, and the other spring is caused to move by the movement of the operating arm in either one of the raised position and the lowered position. Since the rocking member is rocked, the change in the biasing force of the spring can be small, the load sensed by the float can be made substantially constant, and another spring can be placed at any position of the connecting portion of the connecting member. Since it is connected, the biasing force of other springs can be adjusted according to the condition of the rice field.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a body lifting device in a paddy field vehicle according to the present invention.

FIG. 2 is a side view showing the whole of a walk-behind rice transplanter to which the body lifting device of the above-described embodiment can be applied.

FIG. 3 is a side view showing a body raising / lowering device in the above-mentioned walk-behind rice transplanter.

FIG. 4 is an exploded perspective view showing an example of a body lifting device in a conventional paddy field vehicle.

[Explanation of symbols]

 4 Airframe 7 Paddy Wheel 9 Hydraulic Actuator (Hydraulic Cylinder) 10 Hydraulic Switching Valve 10a Operation Arm 11 Earth Pressure Sensing Body (Float) 12 Sensing Rod 22 Rod 23 First Plate 26 Second Plate 69 Connecting Member 69a Connecting Part 70 Other Spring 71 Swing member 93 Spring 96 Spring

Claims (4)

[Claims] 1. A machine body having a working unit capable of moving up and down relative to a paddy wheel, an earth pressure sensor suspended by the machine body and moving by sensing earth pressure from a field surface, and the soil. A hydraulic pressure switching valve that switches between a raised position, a neutral position, and a lowered position according to the movement of the pressure sensor, and a hydraulic pressure that moves the aircraft up and down relatively to the paddy wheel based on the hydraulic pressure from the hydraulic pressure switching bubble. In a body lifting device for a paddy field vehicle comprising an actuator, the hydraulic switching valve has an operation arm connected to a spool, and the operation arm is provided in one of the ascending position and the descending position. The earth pressure sensor is interlocked with an interlocking member that interlocks with the movement to the other side, and is connected to one end of a spring that urges in the other direction, and the other end of the spring is swingable. Supported by And a swing member that moves in a direction in which the urging force of the spring does not change, regardless of the movement of the operation arm. lift device. 2. The operation arm is interlocked with the earth pressure sensor via the interlocking member with respect to the movement in the ascending position direction, and is pulled by the spring in the descending position direction. 1. A body lifting device for a paddy work vehicle according to 1. 3. The other spring is arranged between the swing member and the connecting member, and the swing member swings against the biasing force of the other spring. Alternatively, the airframe lifting device for the paddy field vehicle described in 2. 4. The body lifting device for a paddy work vehicle according to claim 3, wherein a plurality of connecting portions are provided on the connecting member, and one end of the other spring is connected to any one of the connecting portions. .