Rice paddy work machine

Abstract

To configure a work device so that a plurality of floats different in size can be supported easily when they are provided in the work device in a paddy field working machine.SOLUTION: A work device has: a fulcrum member 41 supported along a horizontal direction; many pairs of support arms 41a, 41b, 41c which are connected to the fulcrum member 41 and extended diagonally rear downward; and a plurality of floats 17, 18, 19 which are supported at the back of the pairs of support arms 41a, 41b, 41c so that they can slide vertically around a shaft core along the horizontal direction, and contact and follow a paddy field. A gap W1 in the horizontal direction of the pair of support arms 41a located in a left and right center of the work device and a gap W3 in the horizontal direction of the pair of support arms 41c located in a right part and a left part of the work device differ.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a paddy field working machine in which a working device such as a seedling planting device or a seeding device is supported so as to be able to move up and down at the rear part of a machine body supported by traveling wheels.

Background Art

[0002] In a riding type rice transplanter which is an example of a paddy field working machine, as disclosed in Patent Document 1, a plurality of floats are arranged side by side along the left - right direction and are supported so as to be able to swing up and down below a seedling planting device (corresponding to the working device), and the floats follow the ground surface of the paddy field.

[0003] In Patent Document 1, a long fulcrum member in the shape of a round pipe is supported below the working device along the left - right direction, and a plurality of pairs of support arms are connected to the fulcrum member and extend obliquely rearward and downward, and the floats are supported at the rear parts of the pair of support arms so as to be able to swing up and down around an axis along the left - right direction.

[0004] In Patent Document 1, since all the floats are configured to be substantially the same size in plan view, in all pairs of the pair of support arms, the left - right interval of the pair of support arms is set to be the same.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In a paddy field working machine, depending on whether the number of working rows of the working device is large or small, a large float in plan view or a small float in plan view may be provided on the working device.

[0007] The present invention aims to provide a rice paddy work machine that can easily support floats of different sizes when multiple floats are provided on the work device. [Means for solving the problem]

[0008] The rice paddy work machine of the present invention comprises a machine body supported by wheels for travel, and a work device supported at the rear of the machine body so as to be able to move up and down. The work device comprises a pivot member supported at the lower part of the work device along the left-right direction, a plurality of pairs of support arms connected to the pivot member and extending diagonally downward and rearward, and a plurality of floats supported at the rear of the pairs of support arms so as to be able to swing up and down about an axis along the left-right direction and to follow the contact with the paddy field surface. The left-right distance between the pairs of support arms located in the left-right center of the work device and the left-right distance between the pairs of support arms located on the right and left sides of the work device are set to be different, and a first member is provided that is connected across the upper surfaces of the pairs of support arms. Furthermore, the first member is flat and is connected across the rear ends of the pair of support arms, and the channel-shaped second member is connected across the portion of the pair of support arms that is closer to the pivot member than the first member.

[0009] According to the present invention, a pivot member is supported at the bottom of the work device along the left-right direction, and multiple pairs of support arms are connected to the pivot member and extend diagonally downward and rearward. A float is supported at the rear of the pair of support arms so as to be able to swing up and down about an axis along the left-right direction.

[0010] According to the present invention, the distance between a pair of support arms located in the left and right center of the work device is set to be different from the distance between a pair of support arms located in the left and right sides of the work device. This allows for a configuration where larger floats are supported by support arms with a large lateral spacing, and smaller floats are supported by support arms with a small lateral spacing.

[0011] When multiple floats are provided on a work device, as in Patent Document 1, the multiple floats are often arranged symmetrically in a plan view with respect to the left and right center of the work device. Therefore, even when floats of different sizes are provided on the work device, it is thought that the multiple floats will be arranged symmetrically in a plan view with respect to the left and right center of the work device.

[0012] According to the present invention, the left-right spacing between a pair of support arms located in the left-right center of the work device and the left-right spacing between a pair of support arms located on the right and left sides of the work device are set to be different. Therefore, multiple floats of different sizes can be arranged symmetrically with respect to the left-right center of the work device in a plan view without any difficulty.

[0013] According to the present invention, with a plurality of floats of different sizes, the floats are supported without difficulty by the work device and are arranged symmetrically with respect to the left and right center of the work device in a plan view, thereby improving the support function of the floats in the work device. According to the present invention, the strength of the support arms can be improved by connecting the first member and the second member across a pair of support arms. According to the present invention, when a flat plate-shaped first member and a channel-shaped second member are used, the first member is connected to the rear of the support arm and is positioned close to the portion where the float is supported by the support arm so as to be able to swing up and down. Since the first member is a thin, flat plate, even when the first member is connected to the rear of the support arm, it can reinforce the support arm with the first member while avoiding interference with the up-and-down oscillation of the float.

[0014] In the present invention, it is preferable that the distance between the pair of support arms located on the right and left sides of the work device is set to be greater than the distance between the pair of support arms located in the left-right center of the work device.

[0015] Compared to floats supported in the center of the working device, floats supported on the right and left sides of the working device are more prone to lateral swaying, such as being swung to the right or left, due to the influence of mud waves flowing diagonally to the rear from the front wheels.

[0016] According to the present invention, since the lateral interval between a pair of support arms located on the right and left sides of the working device is larger than the lateral interval between a pair of support arms located at the left and right central portions of the working device, the support strength of the support arms against the lateral sway of the float can be improved.

[0017]

[0018]

[0019] In the present invention, it is preferable that the second member is connected across the lateral surfaces of the pair of support arms.

[0020] For the flat plate-shaped first member, the channel-shaped second member is advantageous in terms of improving the strength of the support arms, but has a relatively large vertical width. According to the present invention, when the second member is connected across the lateral surfaces of the support arms, the second member will fall within the range of the vertical width of the support arms in side view. Even if the second member protrudes above or below the support arms in side view, the second member will protrude slightly above or below the support arms in side view. Thereby, while avoiding interference of the second member with respect to the vertical sway of the float, the support arms can be reinforced by the second member.

[0021] In the present invention, it is preferable that the open portion of the second member faces rearward.

[0022] When the paddy field working machine moves forward, mud on the paddy field surface often scatters from the front to the rear working device of the working device. According to the present invention, the open portion of the channel-shaped second member faces rearward, and even if mud scatters from the front to the rear, it is less likely that mud will enter the inside of the second member. Therefore, it is possible to avoid a state where a large amount of mud enters the second member and hinders the vertical sway of the float.

[0023] In the present invention, it is preferable that a fulcrum shaft supported along the left - right direction is provided across the horizontal surfaces at the rear portions of the pair of support arms, and the float is supported at the rear portions of the pair of support arms so as to be vertically swingable around the axis via the fulcrum shaft.

[0024] In a paddy - field working machine, there may be a case where a fulcrum shaft is supported along the left - right direction across the horizontal surfaces at the rear portions of support arms, and a float is supported at the rear portions of the support arms so as to be vertically swingable via the fulcrum shaft.

[0025] According to the present invention, when the first member is connected across the rear portion of the support arm, in addition to the first member being a thin member because it is in a flat plate shape, the first member is connected across the upper surface portion of the support arm and is provided at a position separated upward from the fulcrum shaft. This is advantageous in terms of reinforcing the support arm by the first member while avoiding interference of the first member with the vertical swing of the float.

[0026] In the present invention, it is preferable that a spring for biasing the float in the forward - upward direction is attached to the fulcrum shaft. [[ID=I6]]

[0027] According to the present invention, when a spring for biasing the float in the forward - upward direction is attached to the fulcrum shaft, due to the fact that the first member is a thin member because it is in a flat plate shape and the first member is provided at a position separated upward from the fulcrum shaft, it is advantageous in terms of reinforcing the support arm by the first member while avoiding interference of the first member with the spring.

[0028] In the present invention, a mounting member is provided attached to the float, and the mounting member is attached to the pivot axis, so that the float is supported at the rear of the pair of support arms so that it can swing up and down around the axis via the pivot axis, the mounting member has a base plate portion attached to the float, and right and left lateral portions extending upward from the right and left portions of the base plate portion and attached to the pivot axis, and in a side view, the lateral portions extend from the front to the rear to above the center line of the support arms, and the float is preferably a float in the center of the left and right sides of the aircraft in a plan view.

[0029] According to the present invention, a mounting member is provided having a base portion and right and left lateral portions. The base portion of the mounting member is attached to a float, the lateral portions of the mounting member are attached to a pivot axis, and the base portion of the mounting member is formed in a rectangular shape in plan view. This suppresses lateral sway, such as when the float swings to the right or left around the pivot point near the pivot axis in a plan view. In particular, since the lateral section extends from the front to the rear above the centerline of the support arm, a contact surface with the support arm can be secured, effectively suppressing lateral sway.

[0030] In the present invention, it is preferable that a height adjuster connected to the pivot member and operable by human intervention is provided, and a guide portion that guides the operation of the height adjuster and can hold the height adjuster when the height adjuster is engaged with it is provided, and when the height adjuster is operated, the pivot member is rotated and the pair of support arms are swung up and down to change the height of the float relative to the work device, and the height of the float relative to the work device is maintained when the height adjuster is held by the guide portion, and a reinforcing member is provided in the portion of the guide portion to which the height adjuster is engaged.

[0031] In some rice paddy work machines, a manually operable height adjuster is connected to a pivot member, and by operating the height adjuster, the pivot member is rotated, the support arm is swung up and down, and the height of the float relative to the work device is changed. A guide section is provided to guide the height adjuster, and the height of the float relative to the working device is maintained when the height adjuster is engaged with and held in the guide section.

[0032] When the float is in contact with the paddy field surface, its weight is primarily supported by the field. In contrast, when a paddy field implement turns at the edge of a ridge or travels on a road, for example, the implement is lifted off the paddy field surface, and the weight of the float is shifted from the height adjuster to the guide section.

[0033] According to the present invention, since a reinforcing member is provided in the part of the guide section where the height adjuster is engaged, the strength of the guide section can be improved when the working device is lifted from the field surface and the weight of the float is applied from the height adjuster to the guide section. [Brief explanation of the drawing]

[0034] [Figure 1] This is a left side view of a riding-type rice transplanter. [Figure 2] This is a plan view of the seedling planting device and the land leveling device. [Figure 3] This is a plan view showing the support structure for the center float and side floats. [Figure 4] This is a front view of the area around the center float. [Figure 5] This is a left side view of the area near the center float. [Figure 6] This is a left side view of the area near the center float. [Figure 7] This is a left side view of the area near the rear of the center float. [Figure 8] This is a plan view of the area near the rear of the center float. [Figure 9] This is a left side view of the area near the side floats. [Figure 10] This is a left side view of the area near the side floats. [Figure 11] This is a plan view showing the support structure of the side float. [Figure 12] This is a plan view of the center float. [Figure 13] This is a bottom view of the center float. [Figure 14] This is a front view of the center float. [Figure 15] This is a left side view of the center float. [Figure 16] This is a left side view showing the lifting mechanism of the ground leveling device. [Figure 17] This is a plan view of the guide section. [Figure 18] This is a cross-sectional view of the guide section. [Figure 19] This is a schematic diagram showing the coordination between the control device and each component. [Figure 20] This is a left side view of the vicinity of the side float in the seventh alternative embodiment of the invention. [Modes for carrying out the invention]

[0035] Figures 1 to 20 show an example of a paddy field work machine, a riding-type rice transplanter. In Figures 1 to 20, F indicates the forward direction, B indicates the backward direction, U indicates the upward direction, D indicates the downward direction, R indicates the right direction, and L indicates the left direction.

[0036] (Overall configuration of a riding-type rice transplanter) As shown in Figure 1, the machine body 3 is supported by the right and left front wheels 1 (corresponding to the wheels for driving) and the right and left rear wheels 2 (corresponding to the wheels for driving). A link mechanism 4 extends from the rear of the machine body 3 toward the rear, and a seedling planting device 5 (corresponding to the work device) is supported at the rear of the link mechanism 4. A fertilizer applicator 6 is supported at the rear of the machine body 3, and a soil leveling device 30 is supported at the front of the seedling planting device 5. By extending and retracting the hydraulic cylinder 7, the link mechanism 4 is raised and lowered, and the seedling planting device 5 is raised and lowered by the link mechanism 4. The hydraulic cylinder 7 is connected across the rear of the machine body 3 and the link mechanism 4. A driver's seat 8 and a steering wheel 9 for steering the front wheels 1 are provided on the machine body 3. Right and left support frames 10 are connected to the right and left front parts of the machine body 3 and extend upward, and a spare seedling tray 11 is attached to the support frames 10.

[0037] (Overall configuration of the seedling planting device) As shown in Figures 1, 2, and 3, the seedling planting device 5 is configured as an 8-row planting type and includes a feed case 12, a support frame 13, a planting transmission case 14, a rotating case 15, a planting arm 16, a center float 17 (corresponding to a float), side floats 18 and 19 (corresponding to floats), and a seedling tray 20. The feed case 12 is supported at the lower rear of the link mechanism 4, and the square pipe-shaped support frame 13 is connected to the feed case 12 and extends along the left-right direction. Four planting transmission cases 14 are connected to the support frame 13 and extend towards the rear. The rotating case 15 is rotatably supported on the right and left rear of the planting transmission case 14, and a pair of planting arms 16 are attached to the rotating case 15. The seedling tray 20 on which the seedlings are placed is supported on the planting transmission case 14 so as to be able to reciprocate along the left-right direction. As the machine 3 moves forward, the leveling device 30 levels the field surface G (see Figure 5). In the seedling planting device 5, the seedling tray 20 is driven back and forth along the left and right direction, while the rotating case 15 is driven to rotate, and the planting arm 16 takes seedlings from the seedling tray 20 and plants them in the field surface G.

[0038] (Configuration of the transmission system to the rotating case in a seedling planting device) As shown in Figure 2, power from an engine (not shown) mounted on the aircraft body 3 is transmitted to an input shaft 27 inside the feed case 12 via a transmission shaft 26 (see Figure 1). An output shaft 28 is provided at the bottom of the feed case 12, and the power transmitted to the input shaft 27 is transmitted to the output shaft 28 via a transmission chain 29.

[0039] The power from the output shaft 28 of the feed case 12 is transmitted to the drive shaft 35 via the transmission shaft 32, input shaft 31, torque limiter 33, transmission chain 34, and minority clutch 36 housed inside the cylindrical cover 37, causing the drive shaft 35 to rotate, and the rotating case 15 and planting arm 16 to rotate in the counterclockwise direction as shown in Figure 1.

[0040] (Overall configuration of the fertilizer application system) As shown in Figures 1 and 3, the fertilizer applicator 6 includes a hopper 21, a dispensing unit 22, a blower 23, a furrower 24, and a hose 25. As the machine 3 moves forward, the fertilizer from the hopper 21 is dispensed into the hose 25 by the dispensing unit 22, and air from the blower 23 is supplied to the hose 25, supplying the fertilizer through the hose 25 to the furrower 24. As the machine 3 moves forward, the furrower 24 forms furrows in the field surface G (see Figure 5), and the fertilizer supplied to the furrower 24 is supplied from the furrower 24 into the furrows in the field surface G, and the furrows in the field surface G are filled by the covering soil member 38.

[0041] (Configuration of the support arm of the pivot member) As shown in Figures 3, 4, and 5, the seedling planting device 5 (working device) has a pivot member 41 supported at the bottom of the seedling planting device 5 (working device) along the left-right direction, multiple pairs of support arms 41a, 41b, and 41c connected to the pivot member 41 and extending diagonally downward and rearward, and multiple center floats 17 (floats) and side floats 18, 19 (floats) supported at the rear of the pairs of support arms 41a, 41b, and 41c so as to be able to swing up and down around an axis P2 along the left-right direction and follow the ground contact with the field surface G.

[0042] As shown in Figure 3, the left-right spacing W1 between the pair of support arms 41a of the pivot member 41, the left-right spacing W2 between the pair of support arms 41b of the pivot member 41, and the left-right spacing W3 between the pair of support arms 41c of the pivot member 41 are the same value, while spacing W3 is larger than spacings W1 and W2.

[0043] As shown in Figures 3, 7, 8, and 9, in the support arms 41a and 41b of the pivot member 41, a flat plate-shaped first member 39 is connected across the upper surface of the front-to-rear intermediate portion of the support arms 41a and 41b of the pivot member 41. A channel-shaped second member 40 is connected across the upper surface of the rear portion of the support arms 41a and 41b of the pivot member 41.

[0044] As shown in Figures 3, 10, and 11, a flat plate-shaped first member 39 is connected to the upper rear portion of the support arm 41c of the pivot member 41.

[0045] A channel-shaped second member 40 is connected across the front-to-rear intermediate portion of the support arm 41c of the pivot member 41, with the open portion of the second member 40 facing forward. The second member 40 is connected across the lateral surface of the support arm 41c of the pivot member 41, and in a side view, the second member 40 does not extend above or below the upper and lower ends of the support arm 41c of the pivot member 41 (see Figure 10).

[0046] As a result of the above configuration, as shown in Figure 3, the left-right spacing W1 between the pair of support arms 41a located in the left-right center of the seedling planting device 5 (working device) and the left-right spacing W3 between the pair of support arms 41c located on the right and left sides of the seedling planting device 5 (working device) are set to be different.

[0047] The distance W3 between a pair of support arms 41c located on the right and left sides of the seedling planting device 5 (working device) is set to be greater than the distance W1 between a pair of support arms 41a located in the left and right center of the seedling planting device 5 (working device).

[0048] As shown in Figures 10 and 11, a flat first member 39 is connected across the rear of a pair of support arms 41c of the pivot member 41, and a channel-shaped second member 40 is connected across the portion of the pair of support arms 41c of the pivot member 41 that is closer to the pivot member 41 than the first member 39. The second member 40 is connected across the lateral surfaces of the pair of support arms 41c of the pivot member 41.

[0049] (Center float configuration) - 1 As shown in Figures 12 to 15, the center float 17 is manufactured by blow molding and has a first rear portion 91 and a second front portion 92. The right side of the second portion 92 is located below the planting depth lever 42 and the guide portion 43 (see Figure 4).

[0050] As shown in Figures 12 and 15, the center float 17 (float) has a first portion 91 supported at the bottom of the seedling planting device 5 (working device) and a second portion 92 connected to the front of the first portion 91 and extending diagonally forward and upward from the front of the first portion 91 in a side view.

[0051] The horizontal width W21 of the second part 92 is greater than twice (or three times) the horizontal width W11 of the first part 91. The left-right width W22 spanning from the right end of the first part 91 to the right end of the second part 92 is greater than the left-right width W11 of the first part 91, and the left-right width W23 spanning from the left end of the first part 91 to the left end of the second part 92 is greater than the left-right width W11 of the first part 91. The length L2 in the front-to-back direction of the second part 92 is shorter than the length L in the front-to-back direction of the first part 91. As shown in Figure 4, the planting depth lever 42 (float position changing part) is located within the width W21 in the left-right direction of the second part 92 when viewed from the front.

[0052] (Center float configuration) - 2 As shown in Figures 12 to 15, in the center float 17, the upper surface 91a and lower surface 91b of the first portion 91 are substantially parallel in a side view. The upper surface 92a of the second portion 92 extends substantially linearly diagonally forward and upward from the front of the upper surface 91a of the first portion 91 in a side view.

[0053] In the second portion 92 of the center float 17, the lower surface portion 92b of the second portion 92 (corresponding to the first lower surface portion) extends forward in parallel from the front of the lower surface portion 91b of the first portion 91, when viewed from the side.

[0054] In a side view, the arc-shaped connecting portion 92d of the second portion 92 extends diagonally forward and upward from the front of the lower surface portion 92b of the second portion 92 in a side view. The lower surface portion 92c of the second portion 92 (corresponding to the second lower surface portion) extends diagonally forward and upward from the front (upper part) of the connecting portion 92d of the second portion 92 in a side view.

[0055] As shown in Figure 15, in the upper surface 92a and lower surface 92c of the second portion 92, in a side view, the upward angle θ1 of the lower surface 92c of the second portion 92 relative to the lower surface 91b of the first portion 91 is greater than the upward angle θ2 of the upper surface 92a of the second portion 92 relative to the lower surface 91b of the first portion 91.

[0056] In a side view, the upper surface portion 92a of the second portion 92 extends diagonally forward and upward from the front of the upper surface portion 91a of the first portion 91. The lower surfaces 92b and 92c of the second portion 92, in a side view, have a first lower surface 92b that extends forward parallel to the lower surface 91b of the first portion 91, and a second lower surface 92c that extends diagonally forward and upward from the front of the first lower surface 92b. In a side view, the upward angle θ1 of the second lower surface 92c of the second part 92 relative to the lower surface 91b of the first part 91 is greater than the upward angle θ2 of the upper surface 92a of the second part 92 relative to the lower surface 91b of the first part 91.

[0057] In the second part 92, the joint portion 90 (part) corresponding to the joint portion of a pair of molds formed by blow molding is located, in a side view, closer to the lower parts 92b and 92c of the second part 92 than the intermediate portion between the upper part 92a and the lower parts 92b and 92c of the second part 92.

[0058] (Center float configuration) - 3 As shown in Figures 12 to 15, in the center float 17, downward-facing recesses 93 on the right and left are provided on the upper surface 92a of the second portion 92, and upward-facing recesses 94 on the lower surface 92b, 92c and the connecting portion 92d of the second portion 92.

[0059] The furrowing device 24 (see Figures 1, 3, and 4) of the fertilizer applicator 6 is attached to the recesses 93 and 94 of the center float 17, and the soil covering member 38 (see Figures 3, 7, and 8) is attached to the right and left parts of the first part 91. A downward-facing recess 98 is provided on the right side of the upper surface 92a of the second part 92, and the recess 98 is connected to the right recess 93.

[0060] A downward-facing recess 95 is provided on the left side of the upper surface portion 92a of the second portion 92, and an upward-facing recess 96 is provided on the left side of the lower surface portion 92b and the connecting portion 92d of the second portion 92.

[0061] A downward-facing recess 97 (corresponding to the upper recess) is provided in the upper surface portion 92a of the second portion 92 between the right and left recesses 93, and in the portion to the right of the right recess 93. The recess 97 has an elongated shape in the front-to-back direction when viewed from above.

[0062] As shown in Figures 12 and 15, a recess 97 (upper recess) is provided on the upper surface 92a of the second part 92, extending from the upper surface 92a toward the lower surfaces 92b and 92c of the second part 92. The recess 97 (upper recess) is formed along the front-rear direction, and its depth from the upper surface 92a of the second part 92 becomes shallower towards the rear.

[0063] (Center float configuration) - 4 As shown in Figures 4, 13, and 14, in the center float 17, an upwardly recessed recess 99 (corresponding to the lower recess) is provided on the lower surface portions 92b, 92c and connecting portion 92d of the second portion 92, and an upwardly recessed recess 100 is provided on the lower surface portion 91b of the first portion 91.

[0064] The recess 100 is formed along the front-to-back direction, extending from the rear of the recess 99 to the rear end of the lower surface portion 91b of the first portion 91. The width of the recess 100 in the left-to-right direction is the same as the width of the rear of the recess 99 in the left-to-right direction.

[0065] As shown in Figures 12 to 15, at the right side of the front end of the second part 92, the joint part 90 is formed by bending it so as to be recessed downward from the upper surface part 92a of the second part 92, and an attachment part 101 that fits below the upper surface part 92a of the second part 92 is provided on the joint part 90.

[0066] As shown in Figures 4, 13, and 14, recesses 99 (lower recesses) are provided in the lower surfaces 92b and 92c of the second part, extending toward the upper surface 92a of the second part. The recesses 99 (lower recesses) are formed along the front-to-back direction, and the width of the recesses 99 (lower recesses) in the left-to-right direction is larger towards the front.

[0067] As shown in Figures 12 to 15, a mounting portion 101 is provided at the front end of the second portion 92, which, in a side view, extends below the upper surface portion 92a of the second portion 92, and the height detection unit 50 is attached to the mounting portion 101.

[0068] (Configuration of attaching the pivot member to the support arm in the center float) - 1 As shown in Figures 7 and 8, the center float 17 (float) is provided with a mounting member 59 attached to it. By attaching the mounting member 59 to the pivot shaft 63, the center float 17 (float) is supported at the rear of a pair of support arms 41a of the pivot member 41 so that it can swing up and down around the axis P2 via the pivot shaft 63.

[0069] The mounting member 59 is formed in a rectangular shape in plan view and has a base portion 59a attached to the center float 17 (float), and right and left lateral portions 59b that extend upward from the right and left sides of the base portion 59a and are attached to the pivot shaft 63. The lateral portions 59b extend from the front to the rear above the center line of the support arm 41a.

[0070] (Configuration of attaching the pivot member to the support arm in the center float) - 2 As shown in Figures 5 and 6, the regulating mechanism 67 is attached across the pivot member 41 and the second portion 92 of the center float 17. The regulating mechanism 67 is located to the left of the planting transmission case 14, which is located above the center float 17, and the planting transmission case 14, located above the center float 17, is positioned to the right of the position above the regulating mechanism 67.

[0071] The regulating mechanism 67 includes right and left support members 64, a regulating pin 65, and a regulating link 66. The right and left support members 64 are connected to the portion of the pivot member 41 located above the center float 17 and extend diagonally downward and rearward from the pivot member 41. A top plate (not shown) is connected to the right and left support members 64 over their upper parts, and the regulating pin 65 is attached to the rear of the right and left lateral portions 64b of the support members 64.

[0072] Bracket 69 is attached to recesses 95, 96 (see Figures 12 and 13) in the second portion 92 of the center float 17. The regulating link 66 is formed by bending a long, narrow plate into a channel shape and is supported by bracket 69 so as to be able to swing up and down around an axis P3 along the left-right direction. An elongated hole 66a is opened along the longitudinal direction of the regulating link 66. Right and left support members 64 are positioned inside the regulating link 66 and a regulating pin 65 is inserted into the elongated hole 66a of the regulating link 66.

[0073] When the seedling planting device 5 descends relative to the center float 17 (or when the center float 17 rises relative to the seedling planting device 5), the regulating link 66 swings downward. The regulating pin 65 strikes the front end of the elongated hole 66a of the regulating link 66, stopping the center float 17 from rising relative to the seedling planting device 5 (corresponding to the state in which the center float 17 is restricted to its upper limit position relative to the seedling planting device 5).

[0074] When the seedling planting device 5 rises relative to the center float 17 (or when the center float 17 descends relative to the seedling planting device 5), the regulating link 66 swings upward. The regulating pin 65 strikes the rear end of the elongated hole 66a of the regulating link 66, stopping the center float 17 from descending relative to the seedling planting device 5 (corresponding to the state in which the center float 17 is restricted to its lower limit position relative to the seedling planting device 5).

[0075] (Configuration of attaching the pivot member to the support arm in a side float) - 1 As shown in Figures 10 and 11, the mounting member 60 is attached to the rear of the side float 19. The mounting member 60 has a base portion 60a that is formed in a rectangular shape in plan view, and right and left lateral portions 60b that extend upward from the right and left sides of the base portion 60a.

[0076] The front end of the base plate portion 59a of the mounting member 60 extends forward from the front end of the side portion 60b of the mounting member 60, and the length of the base plate portion 59a of the mounting member 60 in the front-rear direction is longer than the length of the side portion 60b of the mounting member 60 in the front-rear direction. Two points on the front of the base plate portion 60a of the mounting member 60 are connected to the upper surface of the rear of the side float 19 by bolts 73.

[0077] The pivot shaft 63 is supported across the rear lateral surface of the support arm 41c of the pivot member 41. The right and left lateral portions 60b of the mounting member 60 are positioned between the support arm 41c of the pivot member 41, and the right and left lateral portions 60b of the mounting member 60 are attached to the pivot shaft 63 so as to be able to swing up and down around the axis P2.

[0078] A coiled spring 74 is attached to the pivot shaft 63, with one end 74a of the spring 74 touching the rear of the base plate portion 60a of the mounting member 60. Multiple mounting holes 41d are opened in the support arm 41c of the pivot member 41, and the other end 74b of the spring 74 is inserted into the mounting hole 41d.

[0079] The end 74a of the spring 74 biases the rear of the side float 19 downward, thereby biasing the side float 19 in an upward direction around the pivot axis 63 (axis P2). The biasing force of the spring 74 can be changed by inserting the end 74b of the spring 74 into another mounting hole 41d of the support arm 41c of the pivot member 41. As shown in Figure 9, the side float 18 is also provided with a pivot shaft 63, a mounting member 60, and a spring 74, similar to those provided in the side float 19.

[0080] (Configuration of attaching the pivot member to the support arm in a side float) - 2 As shown in Figures 9, 10, and 11, the regulating pin 75 is attached across the lateral surface of the support arm 41b of the pivot member 41 and across the lateral surface of the support arm 41c of the pivot member 41. The stopper portion 41e is attached to the portion of the pivot member 41 located above the side floats 18 and 19.

[0081] Bracket 76 is attached to side floats 18, 19, and regulating link 77 is supported by bracket 76 so as to be able to swing up and down about axis P7 along the left-right direction. An elongated hole 77a is opened along the longitudinal direction of regulating link 77, and regulating pin 75 is inserted into the elongated hole 77a of regulating link 77.

[0082] When the seedling planting device 5 descends relative to the side floats 18 and 19 (when the side floats 18 and 19 rise relative to the seedling planting device 5), the front parts of the side floats 18 and 19 hit the stopper portion 41e of the pivot member 41, stopping the side floats 18 and 19 from rising relative to the seedling planting device 5 (corresponding to a state where the side floats 18 and 19 are restricted to their upper limit position relative to the seedling planting device 5).

[0083] When the seedling planting device 5 rises relative to the side floats 18 and 19 (or when the side floats 18 and 19 descend relative to the seedling planting device 5), the regulating link 77 swings upward. The regulating pin 75 strikes the rear end of the elongated hole 77a of the regulating link 77, stopping the descent of the side floats 18 and 19 relative to the seedling planting device 5 (corresponding to a state where the side floats 18 and 19 are restricted to their lower limit relative to the seedling planting device 5).

[0084] (Configuration of the planting depth lever) As shown in Figures 3, 4, and 8, a manually operable planting depth lever 42 (corresponding to the float position change part) (corresponding to the height adjuster) is connected to the pivot member 41 and extends diagonally forward and upward. The planting depth lever 42 is located to the right of the link mechanism 4 (see Figure 1) and is located above the right side of the second part 92 of the center float 17, which will be described later.

[0085] The guide section 43 is connected to the support frame 13 and is located to the right of the link mechanism 4 (see Figure 1). The planting depth lever 42 is inserted into the guide section 43 and guided by the guide section 43. When the planting depth lever 42 is engaged with the guide section 43, the planting depth lever 42 is held in place by the guide section 43 at any desired position. By engaging the planting depth lever 42 with the guide section 43, the position of the axis P2 can be fixed and the seedling setting depth B1 can be set.

[0086] (Guide section configuration) As shown in Figures 17 and 18, the guide portion 43 has a main body portion 44 and an engaging member 45 (corresponding to a reinforcing member). The main body portion 44 is constructed by bending a flat plate into a channel shape, and openings 44b and 44c are provided in the upper surface portion 44a of the main body portion 44 (corresponding to the reinforcing member).

[0087] The opening 44b of the main body portion 44 is formed in a rectangular shape when viewed from above. The engaging member 45 is flat and has a plate thickness greater than the upper surface portion 44a of the main body portion 44. A rectangular opening 45a is provided in the engaging member 45, and a number of convex engaging portions 45b are provided on the right side of the opening 45a.

[0088] The planting depth lever 42 is inserted into the openings 44b and 45a of the guide section 43 (main body section 44 and engaging member 45) and guided along the openings 44b and 45a of the guide section 43 (main body section 44 and engaging member 45). The planting depth lever 42 is held in the guide section 43 when it engages with the engaging portion 45b of the guide section 43 (engaging member 45). By engaging the planting depth lever 42 with the guide section 43, the position of the axis P2 can be fixed and the seedling setting depth B1 can be set.

[0089] The opening 44c of the main body 44 is formed in a rectangular shape in plan view, and numerous convex engaging portions 44d are provided on the left side of the opening 44c of the main body 44. The seedling dispensing lever 46 is inserted into the opening 44c of the guide section 43 (main body section 44) and guided along the opening 44c of the guide section 43 (main body section 44). The seedling dispensing lever 46 is held in place by the guide section 43 when it engages with the engaging section 44d of the guide section 43 (main body section 44).

[0090] With the above configuration, as shown in Figures 17 and 18, a reinforcing member (the upper surface 44a of the main body 44 and the engaging member 45) is provided at the part (engaging part 45b) of the guide part 43 where the planting depth lever 42 (height adjuster) engages. By providing the reinforcing member in this way, strength can be maintained even when the number of engaging parts 45b is increased. Therefore, while using a guide part 43 of roughly the same size as conventional guides, it is possible to increase the number of engaging parts 45b and perform finer adjustment of the planting depth.

[0091] (Configuration related to the lifting and lowering control of the seedling planting device) As shown in Figures 4, 5, and 6, a height detection unit 50 is provided to detect the height from the center float 17 (float).

[0092] The height detection unit 50 is located in front of the regulating mechanism 67 when viewed from the side. The seedling planting device 5 (working device) is equipped with a pivot member 41 supported at the bottom along the left-right direction, and a support arm 41a connected to the pivot member 41 and extending diagonally downward and rearward. The center float 17 (float) is supported at the rear of the support arm 41a of the pivot member 41 so as to be able to swing up and down around an axis P2 along the left-right direction. The height detection unit 50 is located in front of the pivot member 41 when viewed from the side, and the regulating mechanism 67 is located behind the pivot member 41 when viewed from the side.

[0093] The height detection unit 50 has a regulating unit 48 that regulates at least one of the upper limit position and lower limit position of the center float 17 (float) relative to the seedling planting device 5 (working device). The height detection unit 50 has a regulating unit 48 that restricts the center float 17 (float) to both an upper and lower limit position relative to the seedling planting device 5 (working device).

[0094] (Lifting and lowering control of seedling planting device) - 1 As shown in Figure 19, a lifting control unit 71, which is software, is provided in the control device 70. A control valve 49 is provided to supply and discharge hydraulic fluid to the hydraulic cylinder 7 (see Figure 1) to extend and retract the hydraulic cylinder 7, and the control valve 49 is operated by the lifting control unit 71.

[0095] The state shown in Figure 5 is when the planting depth lever 42 is operated to the foremost position relative to the guide section 43, the axis P2 of the center float 17 and side floats 18,19 are at their highest position relative to the seedling planting device 5, and the seedling setting depth B1 is set to the deepest position.

[0096] The state shown in Figure 6 is when the planting depth lever 42 is operated to its last position relative to the guide section 43, the axis P2 of the center float 17 and side floats 18,19 are in their lowest position relative to the seedling planting device 5, and the seedling setting depth B1 is set to the shallowest position.

[0097] As shown in Figures 5, 6, and 19, in the control device 70 (lifting control unit 71), the height from the field surface G (center float 17) to the height sensor 68 (detection axis 68a) is set as the set height A1. When the height from the field surface G (center float 17) to the height sensor 68 (detection axis 68a) is set to the set height A1, the detection arm 54 (detection value of the height sensor 68) is in the neutral position C1.

[0098] When the planting depth lever 42 is operated forward relative to the guide section 43 (towards the deeper side of the seedling setting depth B1), the linkage rod 58 is operated forward, and the support member 53 is operated upward by the first link 51 and the second link 52, so that the height from the field surface G (center float 17) to the height sensor 68 (detection axis 68a) is maintained at the setting height A1.

[0099] When the planting depth lever 42 is operated to the rear side of the guide section 43 (towards the shallower side of the seedling setting depth B1), the linkage rod 58 is operated to the rear, and the support member 53 is operated downward by the first link 51 and the second link 52, so that the height from the field surface G (center float 17) to the height sensor 68 (detection axis 68a) is maintained at the setting height A1.

[0100] (Lifting and lowering control of seedling planting device) - 2 As shown in Figures 5, 6, and 19, when the seedling planting device 5 moves up and down relative to the center float 17 which follows the ground surface G, the detection arm 54 (detection value of the height sensor 68) moves upward (downward) from the neutral position C1. Therefore, the lifting control unit 71 operates the control valve 49, and the hydraulic cylinder 7 moves the seedling planting device 5 up and down so that the detection arm 54 (detection value of the height sensor 68) returns to the neutral position C1.

[0101] The seedling planting device 5 is raised and lowered so that the detection arm 54 (detection value of height sensor 68) is in the neutral position C1. This maintains the height from the field surface G (center float 17) to the height sensor 68 (detection axis 68a) at the set height A1, and the planting depth of the seedlings by the planting arm 16 is maintained at the set depth B1.

[0102] (Relationship between the height detection unit and the regulatory mechanism of the height detection unit) - 1 The relationship between the regulating unit 48 of the height detection unit 50 and the regulating mechanism 67 of the center float 17 will be explained below.

[0103] As shown in Figures 5 and 6, when the height from the field surface G (center float 17) to the height sensor 68 (detection axis 68a) is set to height A1, and the detection arm 54 (detection value of height sensor 68) is in the neutral position C1 (see Figure 19), in the regulating mechanism 67, the regulating pin 65 is located in the middle of the elongated hole 66a of the regulating link 66.

[0104] When the seedling planting device 5 descends relative to the center float 17 (or when the center float 17 rises relative to the seedling planting device 5), the front of the detection arm 54 hits the front end of the regulating part 48, and the portion of the center float 17 with the height detection part 50 is restricted at the upper limit position of the height detection part 50.

[0105] When the height detection section 50 portion of the center float 17 is restricted at the upper limit position of the height detection section 50, the restricting pin 65 of the restricting mechanism 67 has not reached the front end of the elongated hole 66a of the restricting link 66, and the portion of the restricting mechanism 67 of the center float 17 can still be raised.

[0106] If the portion of the regulating mechanism 67 on the center float 17 rises further due to twisting or the like, the regulating pin 65 on the regulating mechanism 67 will strike the front end of the elongated hole 66a of the regulating link 66, and the portion of the regulating mechanism 67 on the center float 17 will be restricted at the upper limit position of the regulating mechanism 67.

[0107] When the seedling planting device 5 rises relative to the center float 17 (or when the center float 17 descends relative to the seedling planting device 5), the rear of the detection arm 54 hits the rear end of the regulating unit 48, and the portion of the center float 17 near the height detection unit 50 is restricted by the lower limit position of the height detection unit 50.

[0108] When the height detection section 50 of the center float 17 is restricted at the lower limit position of the height detection section 50, the restricting pin 65 of the restricting mechanism 67 has not reached the rear end of the elongated hole 66a of the restricting link 66, and the portion of the restricting mechanism 67 of the center float 17 can still descend.

[0109] If the portion of the regulating mechanism 67 on the center float 17 descends further due to twisting or the like, the regulating pin 65 in the regulating mechanism 67 will strike the rear end of the elongated hole 66a of the regulating link 66, and the portion of the regulating mechanism 67 on the center float 17 will be restricted at the lower limit position of the regulating mechanism 67.

[0110] (Relationship between the height detection unit and the regulatory mechanism of the height detection unit) - 2 With the above configuration, as shown in Figures 5 and 6, the upper limit position of the regulating mechanism 67 is set above the upper limit position of the regulating section 48 of the height detection unit 50, and the lower limit position of the regulating mechanism 67 is set below the lower limit position of the regulating section 48 of the height detection unit 50.

[0111] The height detection unit 50 is provided on either the right or left side of the portion of the center float 17 (float) that is supported by the seedling planting device 5 (working device) so as to be able to swing up and down (the portion of the mounting member 59).

[0112] The regulating mechanism 67 is provided on the right and left sides of the portion of the center float 17 (float) that is supported by the seedling planting device 5 (working device) so as to be able to swing up and down (the portion of the mounting member 59).

[0113] As shown in Figure 12, the center float 17 (float) has a first part 91 that is supported so as to be able to swing up and down on the seedling planting device 5 (working device), and a second part 92 connected to the front of the first part 91, the second part having a left-right width W21 that is larger than the left-right width W11 of the first part 91.

[0114] As shown in Figure 4, the height detection unit 50 is provided on one of the right and left parts of the second part 92. The regulating mechanism 67 is provided on the other of the right and left parts of the second part 92. The planting transmission case 14 is positioned to the left and right of the position above the regulating mechanism 67.

[0115] (Overall configuration of the ground leveling equipment) As shown in Figures 1 and 2, the soil leveling device 30 is supported at the front of the seedling planting device 5, and the soil leveling device 30 is positioned behind the rear wheels 2. As shown in Figures 2 and 16, the leveling device 30 includes a transmission case 80, a support frame 81, a drive shaft 82, leveling rotating bodies 83 and 84, a support frame 85, and a cover 86.

[0116] A support case 78 is connected to the planting transmission case 14 at the left end, and a support bracket 79 is connected to the right end of the support frame 13. The transmission case 80 is supported by the support case 78 so as to be able to swing up and down around the axis P8 of the input shaft 31 and the transmission shaft 32, and extends diagonally forward and downward. The support frame 81 is supported by the support bracket 79 so as to be able to swing up and down around the axis P8, and extends diagonally forward and downward.

[0117] The drive shaft 82 is supported across the front of the transmission case 80 and support frame 81 so as to be rotatable about an axis P9 along the left-right direction. Multiple rotating bodies 83 are mounted on the left and right central parts of the drive shaft 82 so as to be located in front of the center float 17. Multiple rotating bodies 84 are mounted on the right and left parts of the drive shaft 82 so as to be located in front of the side floats 18 and 19.

[0118] A round pipe-shaped support frame 85 is connected across the transmission case 80 and the support frame 81. A sheet metal cover 86 is connected to the support frame 85 and is located behind the rotating bodies 83 and 84.

[0119] The transmission shaft 87 is supported inside the support case 78 and the transmission case 80, and is connected to the input shaft 31 of the planting transmission case 14 at the left end. Inside the transmission case 80, the transmission chain 88 is mounted across the sprocket on the transmission shaft 87 and the sprocket on the drive shaft 82, and a torque limiter 89 is provided between the sprocket on the transmission shaft 87 and the sprocket.

[0120] The power transmitted to the input shaft 31 of the planting transmission case 14 at the left end is transmitted to the drive shaft 82 via the transmission shaft 87, torque limiter 89, and transmission chain 88, causing the drive shaft 82 and rotating bodies 83 and 84 to rotate counterclockwise as shown in the figure. As the rotating bodies 83 and 84 rotate counterclockwise as shown in Figure 16, the paddy field surface G is leveled, and the mud thrown backward from the rotating bodies 83 and 84 is stopped by the cover 86.

[0121] (Configuration of the lifting and lowering mechanism for the ground leveling device) As shown in Figures 4 and 16, the leveling lifting mechanism 105 (corresponding to the leveling device position change section) is provided across the support frame 13 and the leveling device 30, located to the left of the link mechanism 4 (see Figure 1), and above the left side of the second portion 92 of the center float 17. The leveling lifting mechanism 105 includes a support frame 106, a lifting gear 107, a gear mechanism 108, an electric motor 109, and a connecting member 110. The lifting gear 107 is supported on the support frame 106 so as to be able to swing up and down around an axis P10 along the left-right direction. A gear mechanism 108 equipped with a pinion gear 108a and an electric motor 109 that drives the gear mechanism 108 are mounted on the upper part of the support frame 106, and the pinion gear 108a meshes with the lifting gear 107.

[0122] The connecting member 110 is attached to the drive shaft 82 of the leveling device 30 via a bearing, and the upper part of the connecting member 110 is connected to the lifting gear 107. The pinion gear 108a of the gear mechanism 108 is rotated in forward and reverse directions by the electric motor 109, causing the lifting gear 107 to swing up and down around the axis P10, and the support position of the leveling device 30 in the seedling planting device 5 is changed vertically via the connecting member 110. The leveling lifting mechanism 105 (leveling device position changing part) is located within the width W21 in the left-right direction of the second part 92 of the center float 17 when viewed from the front.

[0123] (Configuration of the height adjustment device for the ground leveling equipment) As shown in Figures 16 and 19, a height sensor 111 is provided to detect the angle of the lifting gear 107 relative to the support frame 106, and the value detected by the height sensor 111 is input to the control device 70. By detecting the angle of the lifting gear 107 relative to the support frame 106 using the height sensor 111, the height of the land leveling device 30 relative to the seedling planting device 5 is detected.

[0124] A planting depth sensor 113 is provided to detect the operating position of the planting depth lever 42. The value detected by the planting depth sensor 113 is input to the control device 70, and the seedling set depth B1 (see Figures 5 and 6) is detected based on the operating position of the planting depth lever 42.

[0125] A manually operable height adjustment switch 112 is provided near the control handle 9 (see Figure 1), and the operation signal from the height adjustment switch 112 is input to the control device 70. The height adjustment switch 112 sets and changes the leveling setting height A2 (leveling depth), which is the height from the field surface G to the leveling device 30 (drive shaft 82).

[0126] A ground leveling lifting control unit 72, which is software, is provided in the control device 70. Based on the operation signal of the height adjustment switch 112, the detected value of the height sensor 111, and the detected value of the planting depth sensor 113, the ground leveling lifting control unit 72 operates the electric motor 109 to change the support position of the ground leveling device 30 in the seedling planting device 5 vertically, as described below.

[0127] The seedling setting depth B1 (see Figures 5 and 6) is detected by the planting depth sensor 113, and the height of the land leveling device 30 relative to the seedling planting device 5 is detected by the height sensor 111, thereby detecting the height from the field surface G to the land leveling device 30 (drive shaft 82).

[0128] The electric motor 109 operates so that the height from the paddy field surface G to the leveling device 30 (drive shaft 82) becomes the leveling setting height A2 (leveling depth) set (changed) by the height adjustment switch 112, thereby changing the support position of the leveling device 30 in the seedling planting device 5 vertically.

[0129] When the planting depth lever 42 is operated and the seedling setting depth B1 (see Figures 5 and 6) is changed, the height from the field surface G to the leveling device 30 (drive shaft 82) is detected based on the values ​​detected by the planting depth sensor 113 and the height sensor 111.

[0130] As described above, the electric motor 109 operates so that the height from the field surface G to the leveling device 30 (drive shaft 82) becomes the leveling setting height A2 (leveling depth) set (changed) by the height adjustment switch 112, thereby changing the support position of the leveling device 30 in the seedling planting device 5 vertically.

[0131] As a result, even if the planting depth lever 42 is operated and the seedling setting depth B1 (see Figures 5 and 6) is changed, the height from the field surface G to the leveling device 30 (drive shaft 82) is maintained at the leveling setting height A2 (leveling depth) set (changed) by the height adjustment switch 112.

[0132] (First alternative embodiment of the invention) The recesses 97 and 98 may be eliminated in the upper surface portion 92a of the second portion 92 of the center float 17. In the lower surfaces 92b, 92c and connecting portion 92d of the second part 92 of the center float 17, instead of a recess 99 whose width in the left-right direction increases towards the front, the recess 99 may be made such that, like the recess 100, the width in the left-right direction at the front and the width in the left-right direction at the rear are the same.

[0133] (Second alternative embodiment of the invention) In the center float 17, the widths W22 and W23 shown in Figure 12 may be set to be slightly smaller than the width W11, so that the width W21 is greater than twice the width W11 and less than three times the width W11. The length L2 may be configured to be longer than the length L1.

[0134] (Third alternative form of the invention) The configuration of the center float 17 shown in Figures 12 to 15 may be adopted for the side floats 18 and 19. In this case, the configurations described in (First Alternative Embodiment of the Invention) and (Second Alternative Embodiment of the Invention) above may be adopted for the side floats 18 and 19.

[0135] (Fourth alternative embodiment of the invention) As described above in (Second Alternative Embodiment of the Invention), in the center float 17, if the width W21 shown in Figure 12 is greater than twice the width W11 and less than three times the width W11, the planting depth lever 42 (float position changing part) may be provided outside the range of the left-right width W21 of the second part 92 when viewed from the front.

[0136] Similarly, the leveling lifting mechanism 105 (leveling device position changing section) may be provided outside the range of the left-right width W21 of the second portion 92 of the center float 17 when viewed from the front. The height detection unit 50 may be located outside the range of the left-right width W21 of the second portion 92 of the center float 17 when viewed from the front.

[0137] (Fifth alternative embodiment of the invention) In the support arms 41a, 41b, and 41c of the pivot member 41 shown in Figure 3, the spacing W1 and spacing W2 may be the same value, and the spacing W3 may be smaller than the spacings W1 and W2.

[0138] The intervals W1, W2, and W3 may be different values ​​from each other. In this case, the values ​​of the intervals W1, W2, and W3 may be set such that the following relationships (1) to (4) are true. (1) Spacing W1 > Spacing W2 > Spacing W3 (2) Interval W1 < Interval W2 < Interval W3 (3) Interval W1 > Interval W2 = Interval W3 (4) Interval W1 < Interval W2 = Interval W3

[0139] (Sixth alternative embodiment of the invention) In the support arms 41a and 41b of the pivot member 41, similar to the support arm 41c of the pivot member 41 shown in Figures 10 and 11, the first member 39 may be connected across the rear portion of the support arms 41a and 41b of the pivot member 41, and the second member 40 may be connected across the portion of the support arms 41a and 41b of the pivot member 41 that is closer to the pivot member 41 than the first member 39. The second member 40 may also be connected across the lateral portion of the support arms 41a and 41b of the pivot member 41.

[0140] (Seventh alternative embodiment of the invention) In the case where the second member 40 is connected across the lateral surfaces of the support arms 41b and 41c of the pivot member 41, the open portion of the second member 40 may be configured to face rearward, as shown in Figure 20. With the above configuration, the open portion of the second member 40 faces backward.

[0141] In the support arm 41a of the pivot member 41, if the second member 40 is connected across the lateral surface of the support arm 41a of the pivot member 41, the open portion of the second member 40 may be configured to face rearward, as shown in Figure 20.

[0142] In the case where the second member 40 is connected across the lateral surfaces of the support arms 41a, 41b, and 41c of the pivot member 41, the open portion of the second member 40 may be configured to face downward.

[0143] (Eighth alternative form of the invention) In the regulating section 48 of the height detection section 50 shown in Figures 5 and 6, an upper limit position may be provided and a lower limit position may be abolished, or a lower limit position may be provided and an upper limit position may be abolished. In the regulating mechanism 67, an upper limit position may be provided and a lower limit position may be abolished, or a lower limit position may be provided and an upper limit position may be abolished.

[0144] In the above configuration, the combinations may be as described in (1) to (6) below. (1) An upper limit position is established in the regulating section 48 of the height detection section 50 and a lower limit position is abolished. An upper limit position is established in the regulating mechanism 67 and a lower limit position is abolished. (2) In the height detection unit 50, the upper limit position is abolished and a lower limit position is provided in the regulating unit 48. In the regulating mechanism 67, the upper limit position is abolished and a lower limit position is provided. (3) In the regulating section 48 of the height detection section 50, an upper limit position is established and a lower limit position is abolished. In the regulating mechanism 67, the upper limit position is abolished and a lower limit position is established. (4) In the regulating section 48 of the height detection section 50, the upper limit position is abolished and a lower limit position is established. In the regulating mechanism 67, an upper limit position is established and a lower limit position is abolished. (5) The height detection unit 50 has a regulating unit 48 which is either an upper limit position or a lower limit position. The regulating mechanism 67 has both an upper limit position and a lower limit position. (6) The height detection unit 50 has both an upper limit position and a lower limit position in the regulating unit 48. The regulating mechanism 67 has either an upper limit position or a lower limit position.

[0145] (Ninth alternative embodiment of the invention) In the height detection unit 50 and the regulating mechanism 67, the height detection unit 50 may be provided on the left side of the second portion 92 of the center float 17, and the regulating mechanism 67 may be provided on the right side of the second portion 92 of the center float 17.

[0146] (Tenth alternative embodiment of the invention) In the seedling planting device 5, the rotating case 15 may be eliminated, and one planting arm 16 may be rotatably supported on the right side of the planting transmission case 14, and another planting arm 16 may be rotatably supported on the left side of the planting transmission case 14. Instead of the seedling planting device 5, a seeding device (not shown) for supplying rice seeds to the field surface G may be provided as a working device. [Industrial applicability]

[0147] The present invention can be applied to a paddy field work machine in which a work device such as a seedling planting device or a seed sowing device is supported at the rear of a machine body supported by wheels for travel, and the device is capable of being raised and lowered. [Explanation of symbols]

[0148] 1. Front wheel 2 Rear wheels (wheels) 3 aircraft 5 Seedling planting device (work device) 17 Center float (float) 30 Ground leveling equipment 39. First component 40 Second Member 42. Planting depth lever (float position change part) 50 Height detection unit 71 Lifting control unit 90 Connection part (part) 91 Part 1 91b Bottom part 92 Part 2 92a Top part 92b Bottom part 92c Bottom part 97 Recess (Upper recess) 99 Recess (lower recess) 101 Mounting part 105 Ground leveling device position change section A1 Setting height G Tamen L1 Length L2 Length W11 Width W21 Width W22 Width W23 Width θ1 Front upward angle θ2 Front upward angle

Claims

1. The aircraft is supported by wheels for propulsion, The aircraft is equipped with a work device that is supported at the rear so as to be able to be raised and lowered, The aforementioned working device includes a pivot member supported at the lower part of the working device along the left-right direction, multiple pairs of support arms connected to the pivot member and extending diagonally downward and rearward, and multiple floats supported at the rear of the pairs of support arms so as to be able to swing up and down about an axis along the left-right direction, and which follow the contact with the field surface. The distance between the pair of support arms located in the left-right center of the work device and the distance between the pair of support arms located on the right and left sides of the work device are set to be different. A first member is provided, which is connected across the upper surfaces of the pair of support arms. The first member is flat, The first member is connected across the rear of the pair of support arms, A paddy field implement in which a channel-shaped second member is connected to the portion of the pair of support arms that is closer to the pivot member than the first member.

2. The paddy field work machine according to claim 1, wherein the distance in the left-right direction between the pair of support arms located on the right and left sides of the work device is set to be greater than the distance in the left-right direction between the pair of support arms located in the left-right center of the work device.

3. The paddy field work machine according to claim 1, wherein the second member is connected across the lateral surfaces of the pair of support arms.

4. The paddy field work machine according to claim 1, wherein the open portion of the second member faces rearward.

5. The pair of support arms are provided with a pivot axis that is supported along the left-right direction across the lateral surface of the rear portion, The paddy field implement according to claim 1, wherein the float is supported at the rear of the pair of support arms so as to be able to swing up and down about the axis via the pivot axis.

6. The paddy field implement according to claim 5, wherein a spring that biases the float in an upward direction is attached to the pivot shaft.

7. The float is equipped with an attachment member, By attaching the mounting member to the pivot axis, the float is supported at the rear of the pair of support arms so that it can swing up and down around the axis via the pivot axis. The rice paddy work machine according to claim 5, wherein the mounting member has a base plate portion attached to the float, and right and left lateral portions extending upward from the right and left portions of the base plate portion and attached to the pivot axis, and in a side view, the lateral portions extend from the front to the rear above the center line of the support arm, and the float is a float in the center of the left and right sides of the machine in a plan view.

8. A height adjuster connected to the aforementioned pivot member and operable by human intervention, The device is provided with a guide portion that guides the operation of the height adjuster and can hold the height adjuster when the height adjuster is engaged with it. When the height adjuster is operated, the pivot member is rotated, the pair of support arms are swung up and down, and the height of the float relative to the work device is changed, and when the height adjuster is held by the guide portion, the height of the float relative to the work device is maintained. The paddy field work machine according to claim 1, wherein a reinforcing member is provided in the portion of the guide section to which the height adjuster is engaged.

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