Paddy field operation machine

Abstract

A paddy field working machine is provided with a height detection unit (50) for detecting the height of a working device from a floating plate (17), and a lifting control unit for lifting and operating the working device with respect to a machine body on the basis of the detection of the height detection unit (50) so that the working device is maintained at a preset height (A1) from a field surface (G). The paddy field working machine is provided with a limiting mechanism (67), and the limiting mechanism (67) is separated from the height detection part and limits at least one of the upper limit position and the lower limit position of vertical swinging of the floating plate (17) relative to the working device.

Description

Technical Field

[0001] The present invention relates to a paddy field working machine in which working devices such as a seedling transplanter and a seeding device are supported in a liftable manner at the rear of a body supported by traveling wheels. Background Art

[0002] In a riding type transplanter as an example of a paddy field working machine, as disclosed in Patent Document 1 and Patent Document 2, a floating plate is supported by the lower part of a seedling transplanter (equivalent to a working device) so as to be able to swing up and down, and the floating plate follows the ground surface of the paddy field.

[0003] In Patent Document 1 and Patent Document 2, a height detection unit for detecting the height of the seedling transplanter from the floating plate is provided on the floating plate, and the height of the seedling transplanter from the floating plate is detected by the height detection unit as the height of the seedling transplanter from the ground surface of the paddy field.

[0004] Based on the detection by the height detection unit, the seedling transplanter is automatically lifted and lowered relative to the body so that the seedling transplanter is maintained at a preset height from the ground surface of the paddy field, thereby maintaining the insertion depth of the seedlings of the seedling transplanter at a preset depth.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2013-59267

[0008] Patent Document 2: Japanese Patent Laid-Open No. 2016-49067 Summary of the Invention

[0009] In a paddy field working machine, when a floating plate and a height detection unit are provided, a restricting mechanism is sometimes provided on the floating plate, and in the up-and-down swing of the seedling transplanter, the floating plate is restricted by the restricting mechanism to its upper limit position or lower limit position relative to the working device.

[0010] An object of the present invention is to simplify the structure when the height detection unit and the restricting mechanism are provided in a paddy field working machine in the case where the height detection unit and the restricting mechanism are provided on the floating plate.

[0011] The paddy field working machine of the present invention includes: a machine body supported by wheels for traveling; a working device that is liftably supported at the rear of the machine body; a floating plate that is swingably supported at the lower part of the working device and follows the ground surface of the paddy field; a height detection unit that detects the height of the working device from the floating plate; a lifting control unit that, based on the detection of the height detection unit, lifts and lowers the working device relative to the machine body so that the working device is maintained at a preset height from the ground surface of the paddy field; and a restricting mechanism that is provided separately from the height detection unit and restricts at least one of the upper limit position and the lower limit position of the vertical swing of the floating plate relative to the working device.

[0012] According to the present invention, a height detection unit that detects the height of the working device from the floating plate is provided on the floating plate, and based on the detection of the height detection unit, the lifting control unit lifts and lowers the working device relative to the machine body so that the working device is maintained at a preset height from the ground surface of the paddy field.

[0013] According to the present invention, a restricting mechanism is provided on the floating plate, and when the floating plate swings vertically relative to the working device, the floating plate is restricted by the restricting mechanism at least one of the upper limit position and the lower limit position of the vertical swing of the floating plate relative to the working device.

[0014] In the present invention, preferably, the upper limit position of the restricting mechanism is set above the upper limit position of the restricting portion, and the lower limit position of the restricting mechanism is set below the lower limit position of the restricting portion.

[0015] In a paddy field working machine, the floating plate is mostly made by blow molding of synthetic resin and is configured to have a large ground contact area. Therefore, the entire floating plate sometimes undergoes elastic deformation in a slightly twisted manner due to unevenness of the paddy field surface or the like.

[0016] As described above, when the floating plate swings upward in a state where the floating plate has undergone elastic deformation, the floating plate sometimes reaches the upper limit position of the restricting mechanism before reaching the upper limit position of the restricting portion of the height detection unit, and thus the floating plate is restricted at the upper limit position by the restricting mechanism. Similarly, when the floating plate swings downward in a state where the floating plate has undergone elastic deformation, the floating plate sometimes reaches the lower limit position of the restricting mechanism before reaching the lower limit position of the restricting portion of the height detection unit, and thus the floating plate is restricted at the lower limit position by the restricting mechanism.

[0017] In the height detection unit, it is preferable to perform the detection of the height detection unit over the entire range of the upper limit position and the lower limit position of the restricting portion of the height detection unit. Therefore, if the above-described state occurs, it is difficult to perform the detection of the height detection unit over the entire range of the upper limit position and the lower limit position of the restricting portion of the height detection unit.

[0018] According to the present invention, the upper limit position of the limiting mechanism is set above the upper limit position of the limiting part of the height detection part, and the lower limit position of the limiting mechanism is set below the lower limit position of the limiting part of the height detection part.

[0019] Thus, even if the floating plate undergoes elastic deformation, the floating plate easily reaches the upper limit position of the limiting part of the height detection part before reaching the upper limit position of the limiting mechanism, and the floating plate easily reaches the lower limit position of the limiting part of the height detection part before reaching the lower limit position of the limiting mechanism. Therefore, it is easy to perform the detection of the height detection part within the entire range of the upper limit position and the lower limit position of the limiting part of the height detection part, and it is possible to prevent the detection performance of the height detection part from deteriorating.

[0020] In the present invention, preferably, the height detection part is provided in a part of the floating plate on one side of the right side and the left side with respect to the part that can swing up and down and is supported by the working device, and the limiting mechanism is provided in a part of the floating plate on the other side of the right side and the left side with respect to the part that can swing up and down and is supported by the working device.

[0021] According to the present invention, the height detection part and the limiting mechanism are not only provided at different positions in the front-rear direction of the floating plate, but also provided at different positions in the left-right direction of the floating plate. Therefore, the interference between the height detection part and the limiting mechanism is further reduced, and there is no need for a structure for avoiding the interference between the height detection part and the limiting mechanism or the scale of this structure is small, which is advantageous for simplifying the structure when setting the height detection part and the limiting mechanism.

[0022] According to the present invention, with respect to the part of the floating plate that can swing up and down and is supported by the working device, the height detection part is provided in the part on the right side, and the limiting mechanism is provided in the part on the left side. Or, with respect to the part of the floating plate that can swing up and down and is supported by the working device, the height detection part is provided in the left part, and the limiting mechanism is provided in the right part.

[0023] Thus, when the floating plate can swing up and down and is supported by the working device, the left-right balance of the floating plate is improved. Therefore, the floating plate can swing up and down stably, the floating plate will stably ground and follow the field surface, and the height detection from the floating plate to the working device by the height detection part can be performed stably.

[0024] In the present invention, preferably, the height detection part is provided in the front part of the floating plate and is provided in front of the limiting mechanism in a side view.

[0025] According to the present invention, the height detection part is provided in front of the limiting mechanism in a side view.

[0026] Thus, the height detection unit and the restricting mechanism are provided at different positions in the front-rear direction of the floating plate. Therefore, the interference between the height detection unit and the restricting mechanism is reduced, and there is no need for a structure to avoid the interference between the height detection unit and the restricting mechanism or the scale of this structure is small, and the simplification of the structure when the height detection unit and the restricting mechanism are provided can be achieved.

[0027] According to the present invention, for example, when the height detection unit is configured to extend upward from the floating plate, the height detection unit is provided on the front side of the restricting mechanism in a side view. Therefore, it is easy to extend the height detection unit upward from the floating plate while avoiding each part of the working device.

[0028] In the present invention, it is preferable to include: a fulcrum member supported on the lower part of the working device along the left-right direction; and a support arm connected to the fulcrum member and extending obliquely rearward and downward. The floating plate is supported on the rear part of the support arm so as to be able to swing up and down around an axis along the left-right direction. The height detection unit is provided on the front side of the fulcrum member in a side view, and the restricting mechanism is provided on the rear side of the fulcrum member in a side view.

[0029] In a paddy field working machine, the fulcrum member is sometimes supported on the lower part of the working device along the left-right direction, the support arm is sometimes connected to the fulcrum member and extends obliquely rearward and downward, and the floating plate is sometimes arranged to be supported on the rear part of the support arm so as to be able to swing up and down around an axis along the left-right direction.

[0030] According to the present invention, in the above structure, the height detection unit is provided on the front side of the fulcrum member in a side view, and the restricting mechanism is provided on the rear side of the fulcrum member in a side view. Therefore, the fulcrum member is provided between the height detection unit and the restricting mechanism in a side view. Thus, the space between the height detection unit and the restricting mechanism can be effectively utilized to provide the fulcrum member in a side view, and therefore, the fulcrum member, the height detection unit, and the restricting mechanism can be arranged compactly.

[0031] In the present invention, it is preferable that the height detection unit has a restricting portion that restricts at least one of the upper limit position and the lower limit position of the floating plate relative to the working device.

[0032] According to the present invention, for example, when the upper limit position of the floating plate is restricted by the restricting mechanism, the upper limit position and / or the lower limit position of the floating plate is restricted by the restricting portion of the height detection unit. For example, when the lower limit position of the floating plate is restricted by the restricting mechanism, the upper limit position or the lower limit position of the floating plate is restricted by the restricting portion of the height detection unit.

[0033] According to the present invention, for example, when the upper limit position of the floating plate is restricted by the restricting portion of the height detection unit and the restricting mechanism, the restriction of the upper limit position acts on multiple parts of the floating plate. For example, when the lower limit position of the floating plate is restricted by the restricting portion of the height detection unit and the restricting mechanism, the restriction of the lower limit position acts on multiple parts of the floating plate.

[0034] By restricting the upper limit positions (lower limit positions) of multiple parts of the floating plate, the upper limit position (lower limit position) of the floating plate can be stably restricted.

[0035] According to the present invention, for example, when the upper limit position of the floating plate is restricted by the restricting part of the height detection part and the lower limit position of the floating plate is restricted by the restricting mechanism, or when the lower limit position of the floating plate is restricted by the restricting part of the height detection part and the upper limit position of the floating plate is restricted by the restricting mechanism, the floating plate will be restricted by both the upper limit position and the lower limit position, so that large up-and-down swings of the floating plate will be prevented.

[0036] In the present invention, preferably, the height detection part has a restricting part that restricts both the upper limit position and the lower limit position of the floating plate relative to the working device, and the restricting mechanism restricts both the upper limit position and the lower limit position of the up-and-down swing of the floating plate relative to the working device.

[0037] According to the present invention, the upper limit position and the lower limit position of the floating plate are restricted by the restricting part of the height detection part and the restricting mechanism, so that large up-and-down swings of the floating plate will be prevented.

[0038] According to the present invention, the upper limit position of the floating plate is restricted by the restricting part of the height detection part and the restricting mechanism, and the upper limit position restriction is applied to multiple parts of the floating plate. The lower limit position of the floating plate is restricted by the restricting part of the height detection part and the restricting mechanism, and the lower limit position restriction is applied to multiple parts of the floating plate.

[0039] By applying the upper limit position restriction to multiple parts of the floating plate and applying the lower limit position restriction to multiple parts of the floating plate, the upper limit position and the lower limit position of the floating plate can be stably restricted.

[0040] In the present invention, preferably, the restricting mechanism has: a restricting pin supported by the working device; a restricting link supported by the floating plate so as to be swingable about an axis along the left-right direction; and a long hole opened along the long dimension direction of the restricting link, the restricting pin being inserted into the long hole, when the restricting pin reaches one end of the long hole, the floating plate is restricted by the restricting mechanism to the upper limit position, and when the restricting pin reaches the other end of the long hole, the floating plate is restricted by the restricting mechanism to the lower limit position.

[0041] According to the present invention, the restricting mechanism is configured to have a restricting pin and a restricting link with a long hole opened and insert the restricting pin into the long hole, so that the structure of the restricting mechanism can be simplified.

[0042] In the present invention, preferably, the restricting mechanism has a support member supported on the right side of the working device and a support member supported on the left side, and the restricting pin is assembled so as to straddle the support member on the right side and the support member on the left side.

[0043] According to the present invention, the restricting pin is assembled so as to straddle the support member supported on the right side of the working device and the support member supported on the left side, and the restricting pin is supported in a state of being supported at both ends, so that the supporting strength of the restricting pin can be improved.

[0044] In the present invention, preferably, the floating plate has: a first part that is swingably supported on the working device in the vertical direction; and a second part that is connected to the front part of the first part, the lateral width of the second part in the left-right direction being larger than the lateral width of the first part in the left-right direction, the height detection part being provided on one of the right part and the left part of the second part, and the restricting mechanism being provided on the other of the right part and the left part of the second part.

[0045] According to the present invention, in the floating plate having a first part with a small lateral width and a second part with a large lateral width, the height detection part is provided on one of the right part and the left part of the second part of the floating plate, and the restricting mechanism is provided on the other of the right part and the left part of the second part of the floating plate. Thus, the height detection part and the restricting mechanism can be easily arranged on the floating plate in a separated manner in the left-right direction.

[0046] As a result, the interference between the height detection part and the restricting mechanism is further reduced, and there is no need for a structure for avoiding the interference between the height detection part and the restricting mechanism or the scale of this structure is small, which is advantageous for simplifying the structure when the height detection part and the restricting mechanism are provided.

[0047] In the present invention, preferably, the working device is a seedling transplanting device, and the seedling transplanting device has: a seedling stage for placing seedlings; a transplanting arm for taking out seedlings from the seedling stage and transplanting them onto the paddy field surface; and a transplanting transmission case for supporting the transplanting arm on its lateral side part, and the transplanting transmission case is arranged at a position deviated in the left-right direction from a position above the restricting mechanism.

[0048] According to the present invention, the working device is a seedling transplanting device, and the seedling transplanting device is provided with: a seedling stage for placing seedlings; a transplanting arm for taking out seedlings from the seedling stage and transplanting them onto the paddy field surface; and a transplanting transmission case for supporting the transplanting arm on its lateral side part.

[0049] In this case, the restricting mechanism is sometimes provided behind the height detection part in a side view, so that the restricting mechanism and the transplanting transmission case are close to each other in the front-rear direction.

[0050] According to the present invention, the transplanting transmission case is arranged at a position deviated in the left - right direction from above the restricting mechanism, and the interference between the restricting mechanism and the transplanting transmission case is reduced, so that the restricting mechanism and the transplanting transmission case can be arranged smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a left view of a riding - type rice transplanter.

[0052] Figure 2 is a top view of a seedling transplanting device and a soil tilling device.

[0053] Figure 3 is a top view showing the supporting structure of a central floating plate and side floating plates.

[0054] Figure 4 is a front view of the vicinity of the central floating plate.

[0055] Figure 5 is a left view of the vicinity of the central floating plate.

[0056] Figure 6 is a left view of the vicinity of the central floating plate.

[0057] Figure 7 is a left view of the vicinity of the rear part of the central floating plate.

[0058] Figure 8 is a top view of the vicinity of the rear part of the central floating plate.

[0059] Figure 9 is a left view of the vicinity of the side floating plate.

[0060] Figure 10 is a left view of the vicinity of the side floating plate.

[0061] Figure 11 is a top view showing the supporting structure of the side floating plate.

[0062] Figure 12 is a top view of the central floating plate.

[0063] Figure 13 is a bottom view of the central floating plate.

[0064] Figure 14 is a front view of the central floating plate.

[0065] Figure 15 is a left view of the central floating plate.

[0066] Figure 16 is a left view showing the lifting structure of the soil tilling device.

[0067] Figure 17 is a top view of the guiding part.

[0068] Figure 18 It is a cross-sectional view of the guiding part.

[0069] Figure 19 It is a schematic diagram showing the connection of the control device to each part.

[0070] Figure 20 It is a left view near the side floating plate in the seventh other embodiment of the invention. Detailed implementation mode

[0071] Figures 1 - 20 A riding-type rice transplanter, which is an example of a paddy field working machine, is shown in Figures 1 - 20 where F represents the front direction, B represents the rear direction, U represents the upward direction, D represents the downward direction, R represents the right direction, and L represents the left direction.

[0072] (Overall structure of the riding-type rice transplanter)

[0073] As Figure 1 shown, the machine body 3 is supported by front wheels 1 (equivalent to driving wheels) on the right and left sides and rear wheels 2 (equivalent to driving wheels) on the right and left sides. The link mechanism 4 extends rearward from the rear part of the machine body 3, and the seedling planting device 5 (equivalent to the working device) is supported on the rear part of the link mechanism 4. The fertilizer application device 6 is supported on the rear part of the machine body 3, and the soil preparation device 30 is supported on the front part of the seedling planting device 5. The link mechanism 4 is lifted and lowered by the telescopic operation of the hydraulic cylinder 7, so that the seedling planting device 5 is lifted and lowered by the link mechanism 4. The hydraulic cylinder 7 is connected in a manner straddling the rear part of the machine body 3 and the link mechanism 4. The driver's seat 8 and the steering wheel 9 for steering the front wheels 1 are provided on the machine body 3. The right and left support frames 10 are connected to the right and left parts of the front part of the machine body 3 and extend upward, and the spare seedling placement table 11 is assembled on the support frames 10.

[0074] (Overall structure of the seedling planting device)

[0075] As Figure 1 、 Figure 2 、 Figure 3As shown in the figure, the seedling transplanter 5 includes a feed box 12, a support frame 13, a transplanting transmission box 14, a rotating box 15, transplanting arms 16, a central floating plate 17 (equivalent to a floating plate), side floating plates 18, 19 (equivalent to floating plates), and a seedling table 20, and is configured for eight-row transplanting. The feed box 12 is supported at its lower part at the rear of the link mechanism 4, and the square tubular support frame 13 is connected to the feed box 12 and extends in the left-right direction. Four transplanting transmission boxes 14 are connected to the support frame 13 and extend rearward. The rotating box 15 is rotatably supported at the right and left parts of the rear of the transplanting transmission box 14, and a pair of transplanting arms 16 are assembled to the rotating box 15. The seedling table 20 on which the seedlings are placed is supported by the transplanting transmission box 14 so as to be reciprocally movable in the left-right direction. As the machine body 3 advances, the field surface G (refer to Figure 5 ) is prepared by the land preparation device 30. In the seedling transplanter 5, the seedling table 20 is reciprocally driven in the left-right direction, and at the same time, the rotating box 15 is rotationally driven, and the transplanting arms 16 pick up the seedlings from the seedling table 20 and transplant them to the field surface G.

[0076] (Structure of the transmission system for the rotating box in the seedling transplanter)

[0077] As Figure 2 shown, the power of the engine (not shown) mounted on the machine body 3 is transmitted to the input shaft 27 inside the feed box 12 via the transmission shaft 26 (refer to Figure 1 ). The output shaft 28 is provided at the lower part of the feed box 12, and the power transmitted to the input shaft 27 is transmitted to the output shaft 28 via the drive chain 29.

[0078] The power of the output shaft 28 of the feed box 12 is transmitted to the drive shaft 35 via the transmission shaft 32, the input shaft 31, the torque limiter 33, the drive chain 34, and the few-row clutch 36 housed inside the cylindrical cover 37. The drive shaft 35 is rotationally driven, and the rotating box 15 and the transplanting arms 16 are rotationally driven in the Figure 1 counterclockwise direction.

[0079] (Overall structure of the fertilizing device)

[0080] As Figure 1 and Figure 3 shown, the fertilizing device 6 includes a hopper 21, a feeding part 22, a blower 23, a furrow opener 24, and a hose 25. As the machine body 3 advances, the fertilizer in the hopper 21 is sent out to the hose 25 by the feeding part 22, the air supply of the blower 23 is supplied to the hose 25, and the fertilizer is supplied from the hose 25 to the furrow opener 24. As the machine body 3 advances, a furrow is formed on the field surface G (refer to Figure 5 ) by the furrow opener 24, the fertilizer supplied to the furrow opener 24 is supplied from the furrow opener 24 to the furrow on the field surface G, and the furrow on the field surface G is filled by the covering member 38.

[0081] (Structure of the support arm of the fulcrum member)

[0082] As Figure 3 , Figure 4 , Figure 5 shown, the seedling planting device 5 (working device) has: a fulcrum member 41, supported at the lower part of the seedling planting device 5 (working device) in the left - right direction; a plurality of pairs of support arms 41a, 41b, 41c, connected to the fulcrum member 41 and extending obliquely rearward and downward; and a plurality of central floating plates 17 (floating plates) and side floating plates 18, 19 (floating plates), supported at the rear parts of the pair of support arms 41a, 41b, 41c so as to be able to swing up and down around an axis P2 in the left - right direction, and following the ground surface G in contact with it.

[0083] As Figure 3 shown, among the left - right intervals W1 of the pair of support arms 41a of the fulcrum member 41, the left - right interval W2 of the pair of support arms 41b of the fulcrum member 41, and the left - right interval W3 of the pair of support arms 41c of the fulcrum member 41, the interval W1 and the interval W2 are the same value, and the interval W3 is a value larger than the intervals W1, W2.

[0084] As Figure 3 , Figure 7 , Figure 8 , Figure 9 shown, in the support arms 41a, 41b of the fulcrum member 41, a flat - plate - shaped first member 39 is connected in such a way as to straddle the upper surface part of the front - rear intermediate part of the support arms 41a, 41b of the fulcrum member 41. A channel - shaped second member 40 is connected in such a way as to straddle the upper surface part of the rear part of the support arms 41a, 41b of the fulcrum member 41.

[0085] As Figure 3 , Figure 10 , Figure 11 shown, in the support arm 41c of the fulcrum member 41, a flat - plate - shaped first member 39 is connected in such a way as to straddle the upper surface part of the rear part of the support arm 41c of the fulcrum member 41.

[0086] The channel - shaped second member 40 is connected in such a way as to straddle the front - rear intermediate part of the support arm 41c of the fulcrum member 41, and the open part of the second member 40 faces forward. The second member 40 is connected in such a way as to straddle the lateral surface part of the support arm 41c of the fulcrum member 41, and the second member 40 does not protrude upward and downward from the upper end part and the lower end part of the support arm 41c of the fulcrum member 41 in a side view (refer to Figure 10 ).

[0087] With the above structure, as Figure 3As shown, the lateral interval W1 between a pair of support arms 41a at the left and right central portions of the seedling planting device 5 (working device) and the lateral interval W3 between a pair of support arms 41c at the right and left portions of the seedling planting device 5 (working device) are set to be different.

[0088] The lateral interval W3 between a pair of support arms 41c at the right and left portions of the seedling planting device 5 (working device) is set to be larger than the lateral interval W1 between a pair of support arms 41a at the left and right central portions of the seedling planting device 5 (working device).

[0089] As Figure 10 and Figure 11 shown, the flat first member 39 is connected in a manner straddling the rear portions of a pair of support arms 41c of the fulcrum member 41, and the channel-shaped second member 40 is connected in a manner straddling the portions of a pair of support arms 41c of the fulcrum member 41 that are closer to the fulcrum member 41 than the first member 39. The second member 40 is connected in a manner straddling the transverse faces of a pair of support arms 41c of the fulcrum member 41.

[0090] (Structure of the central floating plate) - 1

[0091] As Figures 12 - 15 shown, the central floating plate 17 is manufactured by blow molding and has a first portion 91 as the rear portion and a second portion 92 as the front portion. The right portion of the second portion 92 is located below the planting depth rod 42 and the guide portion 43 (see Figure 4 ).

[0092] As Figure 12 and Figure 15 shown, the central floating plate 17 (floating plate) has: a first portion 91 supported by the lower part of the seedling planting device 5 (working device); and a second portion 92 connected to the front portion of the first portion 91 and extending obliquely forward and upward from the front portion of the first portion 91 in a side view.

[0093] The lateral width W21 in the lateral direction of the second portion 92 is larger than twice (three times) the value of the lateral width W11 in the lateral direction of the first portion 91.

[0094] The lateral width W22 in the lateral direction from the right end portion of the first portion 91 to the right end portion of the second portion 92 is larger than the lateral width W11 in the lateral direction of the first portion 91, and the lateral width W23 in the lateral direction from the left end portion of the first portion 91 to the left end portion of the second portion 92 is larger than the lateral width W11 in the lateral direction of the first portion 91.

[0095] The front - rear length L2 of the second portion 92 is shorter than the front - rear length L1 of the first portion 91.

[0096] AsFigure 4 As shown, the transplanting depth rod 42 (the floating plate position changing part) is disposed within the range of the lateral width W21 in the left - right direction of the second part 92 when viewed from the front.

[0097] (Structure of the central floating plate) - 2

[0098] As Figures 12 - 15 shown, in the central floating plate 17, the upper surface part 91a and the lower surface part 91b of the first part 91 are substantially parallel when viewed from the side. The upper surface part 92a of the second part 92 extends linearly from the front part of the upper surface part 91a of the first part 91 toward the obliquely front - upper direction when viewed from the side.

[0099] In the second part 92 of the central floating plate 17, the lower surface part 92b (equivalent to the first lower surface part) of the second part 92 extends parallel to the front from the front part of the lower surface part 91b of the first part 91 when viewed from the side.

[0100] The connecting part 92d of the second part 92, which is arc - shaped when viewed from the side, extends from the front part of the lower surface part 92b of the second part 92 toward the obliquely front - upper direction when viewed from the side. The lower surface part 92c (equivalent to the second lower surface part) of the second part 92 extends from the front part (upper part) of the connecting part 92d of the second part 92 toward the obliquely front - upper direction when viewed from the side.

[0101] As Figure 15 shown, in the upper surface part 92a and the lower surface part 92c of the second part 92, when viewed from the side, the front - rising angle θ1 of the lower surface part 92c of the second part 92 with respect to the lower surface part 91b of the first part 91 is greater than the front - rising angle θ2 of the upper surface part 92a of the second part 92 with respect to the lower surface part 91b of the first part 91.

[0102] The upper surface part 92a of the second part 92 extends from the front part of the upper surface part 91a of the first part 91 toward the obliquely front - upper direction when viewed from the side.

[0103] The lower surface parts 92b and 92c of the second part 92 have a first lower surface part 92b that extends parallel to the front from the lower surface part 91b of the first part 91 and a second lower surface part 92c that extends from the front part of the first lower surface part 92b toward the obliquely front - upper direction when viewed from the side.

[0104] When viewed from the side, the front - rising angle θ1 of the second lower surface part 92c of the second part 92 with respect to the lower surface part 91b of the first part 91 is greater than the front - rising angle θ2 of the upper surface part 92a of the second part 92 with respect to the lower surface part 91b of the first part 91.

[0105] The joint part 90 (portion) corresponding to the mold clamping part of a pair of molds obtained by blow molding in the second part 92 is located closer to the lower surface parts 92b, 92c of the second part 92 than the middle part between the upper surface part 92a of the second part 92 and the lower surface parts 92b, 92c of the second part 92 when viewed from the side.

[0106] (Structure of the central floating plate) - 3

[0107] As Figures 12 - 15 shown, in the central floating plate 17, concave parts 93 on the right and left that are recessed downward are provided on the upper surface part 92a of the second part 92, and concave parts 94 on the right and left that are recessed upward are provided on the lower surface parts 92b, 92c and the connecting part 92d of the second part 92.

[0108] The furrow opener 24 of the fertilizing device 6 (refer to Figure 1 , Figure 3 , Figure 4 ) is assembled to the parts of the concave parts 93, 94 of the central floating plate 17, and the soil covering member 38 (refer to Figure 3 , Figure 7 , Figure 8 ) is assembled to the right and left parts of the first part 91. A concave part 98 that is recessed downward is provided on the right part of the upper surface part 92a of the second part 92, and the concave part 98 is connected to the concave part 93 on the right side.

[0109] A concave part 95 that is recessed downward is provided on the left part of the upper surface part 92a of the second part 92, and a concave part 96 that is recessed upward is provided on the left part of the lower surface part 92b and the connecting part 92d of the second part 92.

[0110] A concave part 97 (equivalent to the upper concave part) that is recessed downward is provided on the part between the concave parts 93 on the right and left in the upper surface part 92a of the second part 92 and the part on the right side of the concave part 93 on the right side. The concave part 97 is elongated in the front - rear direction when viewed from above.

[0111] As Figure 12 and Figure 15 shown, a concave part 97 (upper concave part) that recesses from the upper surface part 92a of the second part 92 toward the lower surface parts 92b, 92c of the second part 92 is provided on the upper surface part 92a of the second part 92. The concave part 97 (upper concave part) is formed in the front - rear direction, and the depth from the upper surface part 92a of the second part 92 becomes shallower toward the rear side.

[0112] (Structure of the central floating plate) - 4

[0113] As Figure 4 , Figure 13 , Figure 14As shown, in the central floating plate 17, recessed portions 99 (equivalent to downward recessed portions) that are recessed upward are provided on the lower surface portions 92b, 92c, and connecting portion 92d of the second portion 92, and a recessed portion 100 that is recessed upward is provided on the lower surface portion 91b of the first portion 91.

[0114] The recessed portion 100 is formed in the front-rear direction from the rear portion of the recessed portion 99 to the rear end portion of the lower surface portion 91b of the first portion 91. The lateral width in the left-right direction of the recessed portion 100 is the same as the lateral width in the left-right direction of the rear portion of the recessed portion 99.

[0115] As Figures 12 - 15 shown, at the right portion of the front end portion of the second portion 92, the joining portion 90 is bent and formed so as to be recessed downward from the upper surface portion 92a of the second portion 92, and the fitting portion 101 that is recessed downward to the lower side of the upper surface portion 92a of the second portion 92 is provided on the joining portion 90.

[0116] As Figure 4 、 Figure 13 、 Figure 14 shown, recessed portions 99 (downward recessed portions) that are recessed from the lower surface portions 92b, 92c of the second portion toward the upper surface portion 92a of the second portion 92 are provided on the lower surface portions 92b, 92c of the second portion 92. The recessed portions 99 (downward recessed portions) are formed in the front-rear direction, and the lateral width in the left-right direction of the recessed portions 99 (downward recessed portions) is larger toward the front side.

[0117] As Figures 12 - 15 shown, in a side view, the fitting portion 101 that is recessed downward to the lower side of the upper surface portion 92a of the second portion 92 is provided at the front end portion of the second portion 92, and the height detection portion 50 is fitted to the fitting portion 101.

[0118] (Structure for fitting the support arm of the central floating plate to the support member) - 1

[0119] As Figure 7 and Figure 8 shown, a fitting member 59 that is fitted to the central floating plate 17 (floating plate) is provided. By fitting the fitting member 59 to the fulcrum shaft 63, the central floating plate 17 (floating plate) is supported at the rear portions of a pair of support arms 41a of the support member 41 so as to be able to swing up and down about the axis P2 via the fulcrum shaft 63.

[0120] The fitting member 59 is formed in a quadrilateral shape in a top view, and has a substrate portion 59a that is fitted to the central floating plate 17 (floating plate), and lateral side portions 59b on the right and left sides that extend upward from the right and left portions of the substrate portion 59a and are fitted to the right side of the fulcrum shaft 63.

[0121] (Structure for fitting the support arm of the central floating plate to the support member) - 2

[0122] AsFigure 5 and Figure 6 As shown in Figure 6 , the restricting mechanism 67 is assembled so as to straddle the fulcrum member 41 and the second portion 92 of the central floating plate 17. The restricting mechanism 67 is provided on the left side of the planting transmission case 14 located above the central floating plate 17, and the planting transmission case 14 located above the central floating plate 17 is disposed at a position deviated to the right from a position above the restricting mechanism 67.

[0123] The restricting mechanism 67 includes right and left support members 64, a restricting pin 65, and a restricting link 66. The right and left support members 64 are connected to a portion of the fulcrum member 41 located above the central floating plate 17 and extend obliquely rearward and downward from the fulcrum member 41. A top plate portion (not shown) is connected so as to straddle the upper portions of the right and left support members 64, and the restricting pin 65 is assembled so as to straddle the rear portions of the right lateral side portion 64b and the left lateral side portion 64b of the support member 64.

[0124] The bracket 69 is assembled to the concave portions 95, 96 (see Figure 12 and Figure 13 ) of the second portion 92 of the central floating plate 17. The restricting link 66 is formed in a channel shape by bending a slender plate material and is supported by the bracket 69 so as to be able to swing up and down about an axis P3 along the left-right direction. A long hole 66a is opened along the long dimension direction of the restricting link 66. The right and left support members 64 are disposed inside the restricting link 66, and the restricting pin 65 is inserted into the long hole 66a of the restricting link 66.

[0125] When the seedling planting device 5 descends relative to the central floating plate 17 (when the central floating plate 17 ascends relative to the seedling planting device 5), the restricting link 66 swings downward. By bringing the restricting pin 65 into contact with the front end portion of the long hole 66a of the restricting link 66, the ascent of the central floating plate 17 relative to the seedling planting device 5 is prevented (equivalent to a state in which the central floating plate 17 is restricted to its upper limit position relative to the seedling planting device 5).

[0126] When the seedling planting device 5 ascends relative to the central floating plate 17 (when the central floating plate 17 descends relative to the seedling planting device 5), the restricting link 66 swings upward. By bringing the restricting pin 65 into contact with the rear end portion of the long hole 66a of the restricting link 66, the descent of the central floating plate 17 relative to the seedling planting device 5 is prevented (equivalent to a state in which the central floating plate 17 is restricted to its lower limit position relative to the seedling planting device 5).

[0127] (Structure of the support arm of the side floating plate assembled to the fulcrum member) - 1

[0128] As Figure 10 and Figure 11 ​​​​As shown, the assembly member 60 is assembled to the rear part of the side floating plate 19. The assembly member 60 has a substrate portion 60a that is formed in a quadrilateral shape when viewed from above, and right and left lateral side portions 60b that extend upward from the right and left portions of the substrate portion 60a.

[0129] The front end portion of the substrate portion 60a of the assembly member 60 protrudes forward from the front end portions of the lateral side portions 60b of the assembly member 60, and the length of the substrate portion 60a of the assembly member 60 in the front-rear direction is longer than the length of the lateral side portions 60b of the assembly member 60 in the front-rear direction. Two portions at the front of the substrate portion 60a of the assembly member 60 are connected to the upper surface portion at the rear of the side floating plate 19 by bolts 73.

[0130] The fulcrum shaft 63 is supported so as to straddle the horizontal surface portion at the rear of the support arm 41c of the fulcrum member 41. The right and left lateral side portions 60b of the assembly member 60 are disposed between the support arms 41c of the fulcrum member 41, and the right and left lateral side portions 60b of the assembly member 60 are assembled to the fulcrum shaft 63 so as to be able to swing up and down about the axis P2.

[0131] The spiral spring 74 is assembled to the fulcrum shaft 63, and one end portion 74a of the spring 74 abuts against the rear portion of the substrate portion 60a of the assembly member 60. A plurality of assembly holes 41d are formed in the support arm 41c of the fulcrum member 41, and the other end portion 74b of the spring 74 is inserted into the assembly holes 41d.

[0132] The rear portion of the side floating plate 19 is pressed downward by the end portion 74a of the spring 74, and the side floating plate 19 is applied with a force in the forward lifting direction about the fulcrum shaft 63 (axis P2). By inserting the end portion 74b of the spring 74 into other assembly holes 41d of the support arm 41c of the fulcrum member 41, the applied force of the spring 74 can be changed.

[0133] As Figure 9 shown, the same fulcrum shaft 63, assembly member 60, and spring 74 as those of the side floating plate 19 are also provided on the side floating plate 18.

[0134] (Structure of the side floating plate for assembling to the support arm of the fulcrum member) - 2

[0135] As Figure 9 , Figure 10 , Figure 11 shown, the limit pin 75 is assembled so as to straddle the horizontal surface portion of the support arm 41b of the fulcrum member 41 and is also assembled so as to straddle the horizontal surface portion of the support arm 41c of the fulcrum member 41. A stopper portion 41e is assembled to the portion of the fulcrum member 41 located above the side floating plates 18 and 19.

[0136] The bracket 76 is assembled to the side floating plates 18 and 19, and the limiting link 77 is supported by the bracket 76 in such a manner that it can swing up and down about the axis P7 along the left - right direction. A long hole 77a is opened along the long - dimension direction of the limiting link 77, and the limiting pin 75 is inserted into the long hole 77a of the limiting link 77.

[0137] If the seedling planting device 5 descends relative to the side floating plates 18 and 19 (if the side floating plates 18 and 19 ascend relative to the seedling planting device 5), the front parts of the side floating plates 18 and 19 abut against the stopper portion 41e of the fulcrum member 41, and the ascent of the side floating plates 18 and 19 relative to the seedling planting device 5 is blocked (equivalent to a state where the upper limit position of the side floating plates 18 and 19 relative to the seedling planting device 5 is restricted).

[0138] If the seedling planting device 5 ascends relative to the side floating plates 18 and 19 (if the side floating plates 18 and 19 descend relative to the seedling planting device 5), the limiting link 77 swings upward. The limiting pin 75 abuts against the rear end portion of the long hole 77a of the limiting link 77, and the descent of the side floating plates 18 and 19 relative to the seedling planting device 5 is blocked (equivalent to a state where the lower limit position of the side floating plates 18 and 19 relative to the seedling planting device 5 is restricted).

[0139] (Structure of the planting depth rod)

[0140] As Figure 3 、 Figure 4 、 Figure 8 shown, the manually operable planting depth rod 42 (equivalent to the floating plate position changing portion) (equivalent to the height adjusting member) is connected to the fulcrum member 41 and extends obliquely forward and upward. The planting depth rod 42 is provided on the right side of the link mechanism 4 (refer to Figure 1 ), and is provided above the right part of the second portion 92 of the central floating plate 17 described later.

[0141] The guide portion 43 is connected to the support frame 13 and is provided on the right side of the link mechanism 4 (refer to Figure 1 ). The planting depth rod 42 is inserted into the guide portion 43 and guided by the guide portion 43. By engaging the planting depth rod 42 with the guide portion 43, the planting depth rod 42 is held at an arbitrary position of the guide portion 43. By engaging the planting depth rod 42 with the guide portion 43, the position of the axis P2 can be fixed to set the set depth B1 of the seedlings.

[0142] (Structure of the guide portion)

[0143] As Figure 17 and Figure 18 shown, the guide portion 43 has a main body portion 44 and an engaging member 45 (equivalent to a reinforcing member). The main body portion 44 is formed by bending a flat plate into a channel shape, and openings 44b and 44c are opened on the upper surface portion 44a (equivalent to a reinforcing member) of the main body portion 44.

[0144] The opening 44b of the main body portion 44 is formed in a rectangular shape when viewed from above. The engaging member 45 is in a flat plate shape and has a plate thickness thicker than the upper surface portion 44a of the main body portion 44. A rectangular opening 45a is formed in the engaging member 45, and many convex engaging portions 45b are provided on the right side portion of the opening 45a.

[0145] The transplanting depth rod 42 is inserted into the openings 44b and 45a of the guiding portion 43 (main body portion 44 and engaging member 45) and is guided along the openings 44b and 45a of the guiding portion 43 (main body portion 44 and engaging member 45). By engaging the transplanting depth rod 42 with the engaging portion 45b of the guiding portion 43 (engaging member 45), the transplanting depth rod 42 is held by the guiding portion 43. By engaging the transplanting depth rod 42 with the guiding portion 43, the position of the axis P2 can be fixed to set the setting depth B1 of the seedlings.

[0146] The opening 44c of the main body portion 44 is formed in a rectangular shape when viewed from above, and many convex engaging portions 44d are provided on the left side portion of the opening 44c of the main body portion 44.

[0147] The seedling taking amount rod 46 is inserted into the opening 44c of the guiding portion 43 (main body portion 44) and is guided along the opening 44c of the guiding portion 43 (main body portion 44). By engaging the seedling taking amount rod 46 with the engaging portion 44d of the guiding portion 43 (main body portion 44), the seedling taking amount rod 46 is held by the guiding portion 43.

[0148] With the above structure, as Figure 17 and Figure 18 shown, a reinforcing member (the upper surface portion 44a of the main body portion 44 and the engaging member 45) is provided at the portion (engaging portion 45b) in the guiding portion 43 where the transplanting depth rod 42 (height adjusting member) engages. Thus, by providing the reinforcing member, the strength can be maintained even when the number of engaging portions 45b is increased. Therefore, it is possible to apply a guiding portion 43 of the same size as in the past and increase the number of engaging portions 45b to perform extremely fine adjustment of the transplanting depth.

[0149] (Structure related to the lifting control of the seedling transplanting device)

[0150] As Figure 4 、 Figure 5 、 Figure 6 shown, a height detection portion 50 for detecting the height of the central floating plate 17 (floating plate) is provided.

[0151] The height detection portion 50 is provided on the front side of the restricting mechanism 67 when viewed from the side.

[0152] As Figure 4 、 Figure 5 、 Figure 6As shown, a fulcrum member 41 is supported at the lower part of a seedling planting device 5 (working device) along the left - right direction, and a support arm 41a is connected to the fulcrum member 41 and extends obliquely rearward and downward. A central floating plate 17 (floating plate) is supported at the rear part of the support arm 41a of the fulcrum member 41 so as to be able to swing up and down around an axis P2 along the left - right direction.

[0153] The height detection part 50 is provided on the front side of the fulcrum member 41 in side view, and the limiting mechanism 67 is provided on the rear side of the fulcrum member 41 in side view.

[0154] The height detection part 50 has a limiting part 48 that limits at least one of the upper limit position and the lower limit position of the central floating plate 17 (floating plate) relative to the seedling planting device 5 (working device).

[0155] The height detection part 50 has a limiting part 48 that limits both the upper limit position and the lower limit position of the central floating plate 17 (floating plate) relative to the seedling planting device 5 (working device).

[0156] (Lifting control of the seedling planting device) - 1

[0157] As Figure 19 shown, a lifting control part 71 as software is provided in the control device 70. It is equipped with a control valve 49 that performs the supply and discharge operation of working oil to the hydraulic cylinder 7 (refer to Figure 1 ) to make the hydraulic cylinder 7 expand and contract, and the control valve 49 is operated by the lifting control part 71.

[0158] Figure 5 The state shown is the state where the planting depth rod 42 is operated to the most forward position relative to the guide part 43, so that the axis P2 of the central floating plate 17 and the side floating plates 18, 19 is in the most raised state relative to the seedling planting device 5, and the set depth B1 of the seedlings is set to the deepest position.

[0159] Figure 6 The state shown is the state where the planting depth rod 42 is operated to the rearmost position relative to the guide part 43, so that the axis P2 of the central floating plate 17 and the side floating plates 18, 19 is in the most lowered state relative to the seedling planting device 5, and the set depth B1 of the seedlings is set to the shallowest position.

[0160] As Figure 5 、 Figure 6 、 Figure 19 shown, in the control device 70 (lifting control part 71), the height from the field surface G (central floating plate 17) to the height sensor 68 (detection shaft 68a) is set to a set height A1. When the height from the field surface G (central floating plate 17) to the height sensor 68 (detection shaft 68a) is the set height A1, the detection arm 54 (the detection value of the height sensor 68) is in the neutral position C1.

[0161] When the insertion depth rod 42 is operated forward relative to the guide portion 43 (the side where the set depth B1 of the seedlings is deeper), the coupling rod 58 is operated forward, the support member 53 is operated upward by the first link 51 and the second link 52, and the height from the field surface G (central floating plate 17) to the height sensor 68 (detection shaft 68a) is maintained at the set height A1.

[0162] When the insertion depth rod 42 is operated backward relative to the guide portion 43 (the side where the set depth B1 of the seedlings is shallower), the coupling rod 58 is operated backward, the support member 53 is operated downward by the first link 51 and the second link 52, and the height from the field surface G (central floating plate 17) to the height sensor 68 (detection shaft 68a) is maintained at the set height A1.

[0163] (Lifting control of the seedling planting device) - 2

[0164] As Figure 5 、 Figure 6 、 Figure 19 shown, if the seedling planting device 5 moves up and down relative to the central floating plate 17 that follows the ground and adheres to the field surface G, the detection arm 54 (the detection value of the height sensor 68) deviates upward (downward) from the neutral position C1. Therefore, the control valve 49 is operated by the lifting control unit 71, and the seedling planting device 5 is lifted and lowered by the hydraulic cylinder 7 so that the detection arm 54 (the detection value of the height sensor 68) is in the neutral position C1.

[0165] By lifting and lowering the seedling planting device 5 so that the detection arm 54 (the detection value of the height sensor 68) is in the neutral position C1, the height from the field surface G (central floating plate 17) to the height sensor 68 (detection shaft 68a) is maintained at the set height A1, and the insertion depth of the seedlings by the insertion arm 16 is maintained at the set depth B1.

[0166] (Relationship between the limiting part of the height detection part and the limiting mechanism) - 1

[0167] Hereinafter, the relationship between the limiting part 48 of the height detection part 50 and the limiting mechanism 67 of the central floating plate 17 will be described.

[0168] As Figure 5 and Figure 6 shown, when the height from the field surface G (central floating plate 17) to the height sensor 68 (detection shaft 68a) is the set height A1 and the detection arm 54 (the detection value of the height sensor 68) is in the neutral position C1 (refer to Figure 19 ), in the limiting mechanism 67, the limiting pin 65 is located at the front and rear middle part of the long hole 66a of the limiting link 66.

[0169] When the seedling planting device 5 descends relative to the central floating plate 17 (when the central floating plate 17 ascends relative to the seedling planting device 5), the front part of the detection arm 54 abuts against the front end of the restricting portion 48, and the portion of the height detection portion 50 in the central floating plate 17 is restricted by the upper limit position of the height detection portion 50.

[0170] In a state where the portion of the height detection portion 50 in the central floating plate 17 is restricted by the upper limit position of the height detection portion 50, in the restricting mechanism 67, the restricting pin 65 does not reach the front end portion of the elongated hole 66a of the restricting link 66, and the portion of the restricting mechanism 67 in the central floating plate 17 can still ascend.

[0171] If the portion of the restricting mechanism 67 in the central floating plate 17 further ascends due to the torsion of the central floating plate 17 or the like, in the restricting mechanism 67, the restricting pin 65 abuts against the front end portion of the elongated hole 66a of the restricting link 66, and the portion of the restricting mechanism 67 in the central floating plate 17 is restricted by the upper limit position of the restricting mechanism 67.

[0172] When the seedling planting device 5 ascends relative to the central floating plate 17 (when the central floating plate 17 descends relative to the seedling planting device 5), the rear part of the detection arm 54 abuts against the rear end portion of the restricting portion 48, and the portion near the height detection portion 50 in the central floating plate 17 is restricted by the lower limit position of the height detection portion 50.

[0173] In a state where the portion of the height detection portion 50 in the central floating plate 17 is restricted by the lower limit position of the height detection portion 50, in the restricting mechanism 67, the restricting pin 65 does not reach the rear end portion of the elongated hole 66a of the restricting link 66, and the portion of the restricting mechanism 67 in the central floating plate 17 can still descend.

[0174] If the portion of the restricting mechanism 67 in the central floating plate 17 further descends due to the torsion of the central floating plate 17 or the like, in the restricting mechanism 67, the restricting pin 65 abuts against the rear end portion of the elongated hole 66a of the restricting link 66, and the portion of the restricting mechanism 67 in the central floating plate 17 is restricted by the lower limit position of the restricting mechanism 67.

[0175] (Relationship between the restricting portion of the height detection portion and the restricting mechanism) - 2

[0176] With the above structure, as Figure 5 and Figure 6 shown, the upper limit position of the restricting mechanism 67 is set above the upper limit position of the restricting portion 48 of the height detection portion 50, and the lower limit position of the restricting mechanism 67 is set below the lower limit position of the restricting portion 48 of the height detection portion 50.

[0177] The height detection unit 50 is provided at a portion of the central floating plate 17 (floating plate) that is located on one side of the right and left sides with respect to the portion (portion of the assembly member 59) that is swingably supported up and down by the seedling planting device 5 (working device).

[0178] The restricting mechanism 67 is provided at a portion of the central floating plate 17 (floating plate) that is located on the other side of the right and left sides with respect to the portion (portion of the assembly member 59) that is swingably supported up and down by the seedling planting device 5 (working device).

[0179] As Figure 12 shown, the central floating plate 17 (floating plate) has: a first portion 91 that is swingably supported up and down by the seedling planting device 5 (working device); and a second portion 92 that is connected to the front portion of the first portion 91, and the lateral width W21 in the left - right direction of the second portion 92 is greater than the lateral width W11 in the left - right direction of the first portion 91.

[0180] As Figure 4 shown, the height detection unit 50 is provided at one of the right and left portions of the second portion 92. The restricting mechanism 67 is provided at the other of the right and left portions of the second portion 92.

[0181] The planting transmission case 14 is arranged at a position deviated in the left - right direction from above the restricting mechanism 67.

[0182] (Overall structure of the soil preparation device)

[0183] As Figure 1 and Figure 2 shown, the soil preparation device 30 is supported at the front portion of the seedling planting device 5, and the soil preparation device 30 is arranged behind the rear wheels 2.

[0184] As Figure 2 and Figure 16 shown, the soil preparation device 30 includes a transmission case 80, a support frame 81, a drive shaft 82, rotary bodies 83, 84 for soil preparation, a support frame 85, and a cover 86.

[0185] The support box 78 is connected to the left - end portion of the planting transmission case 14, and the support bracket 79 is connected to the right - end portion of the support frame 13. The transmission case 80 is supported by the support box 78 so as to be swingable about the axis P8 of the input shaft 31 and the transmission shaft 32, and extends obliquely forward and downward. The support frame 81 is supported by the support bracket 79 so as to be swingable about the axis P8, and extends obliquely forward and downward.

[0186] The drive shaft 82 is supported across the front parts of the transmission case 80 and the support frame 81 so as to be rotatable about the axis P9 along the left - right direction. A plurality of rotating bodies 83 are assembled to the left - right central part of the drive shaft 82 in such a manner as to be located in front of the central floating plate 17. A plurality of rotating bodies 84 are assembled to the right part and the left part of the drive shaft 82 in such a manner as to be located in front of the side floating plates 18, 19.

[0187] The circular - tubular support frame 85 is connected so as to span across the transmission case 80 and the support frame 81. The metal - plate - made cover 86 is connected to the support frame 85 and is provided behind the rotating bodies 83, 84.

[0188] The transmission shaft 87 is supported so as to span across the inside of 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 assembled so as to span across the sprockets provided on the transmission shaft 87 and the drive shaft 82, and the torque limiter 89 is provided between the transmission shaft 87 and the sprocket.

[0189] 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, the torque limiter 89, and the transmission chain 88, and the drive shaft 82 and the rotating bodies 83, 84 are rotationally driven counter - clockwise in the figure. By rotationally driving the rotating bodies 83, 84 counter - clockwise in Figure 16 the field surface G is leveled, and the mud splashing backward from the rotating bodies 83, 84 is blocked by the cover 86.

[0190] (Lifting structure of the land - leveling device)

[0191] As Figure 4 and Figure 16 shown, the land - leveling lifting mechanism 105 (equivalent to the land - leveling device position changing part) is provided so as to span across the support frame 13 and the land - leveling device 30, is provided on the left side of the link mechanism 4 (refer to Figure 1 ) and is provided above the left part of the second part 92 of the central floating plate 17. The land - 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 by the support frame 106 so as to be able to swing up and down about the axis P10 along the left - right direction. The gear mechanism 108 having a pinion 108a and the electric motor 109 for driving the gear mechanism 108 are assembled to the upper part of the support frame 106, and the pinion 108a meshes with the lifting gear 107.

[0192] The connecting member 110 is assembled to the drive shaft 82 of the soil preparation device 30 via a bearing, and the upper part of the connecting member 110 is connected to the lifting gear 107. By driving the pinion 108a of the gear mechanism 108 forward and backward by the electric motor 109, the lifting gear 107 is swung up and down about the axis P10, and via the connecting member 110, the support position of the soil preparation device 30 in the seedling planting device 5 is changed up and down. It should be noted that the soil preparation lifting mechanism 105 (soil preparation device position changing part) is provided within the lateral width W21 in the left-right direction of the second part 92 of the central floating plate 17 when viewed from the front.

[0193] (Height adjustment structure of soil preparation device)

[0194] As Figure 16 and Figure 19 shown, a height sensor 111 for detecting the angle of the lifting gear 107 relative to the support frame 106 is provided, and the detection value of 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 by the height sensor 111, the height of the soil preparation device 30 relative to the seedling planting device 5 is detected.

[0195] A planting depth sensor 113 for detecting the operating position of the planting depth rod 42 is provided, and the detection value of the planting depth sensor 113 is input to the control device 70, and the set depth B1 of the seedlings is detected based on the operating position of the planting depth rod 42 (refer to Figure 5 and Figure 6 ).

[0196] An artificially operable height adjustment switch 112 is provided near the steering wheel 9 (refer to Figure 1 ), and the operation signal of the height adjustment switch 112 is input to the control device 70.

[0197] The height adjustment switch 112 is a component for setting and changing the height from the field surface G to the soil preparation device 30 (drive shaft 82), that is, the soil preparation set height A2 (soil preparation depth).

[0198] The soil preparation lifting control unit 72 as software is provided in the control device 70. Based on the operation signal of the height adjustment switch 112, the detection value of the height sensor 111, and the detection value of the planting depth sensor 113, the soil preparation lifting control unit 72 operates the electric motor 109 in the manner described below to change the support position of the soil preparation device 30 in the seedling planting device 5 up and down.

[0199] The set depth B1 of the seedlings is detected based on the detection value of the planting depth sensor 113 (refer to Figure 5 and Figure 6) and detect the height of the land preparation device 30 relative to the seedling planting device 5 by means of the height sensor 111, thereby detecting the height from the field surface G to the land preparation device 30 (drive shaft 82).

[0200] The electric motor 109 operates in such a manner that the height from the field surface G to the land preparation device 30 (drive shaft 82) becomes the land preparation set height A2 (land preparation depth) set (changed) by the height adjustment switch 112, and the support position of the land preparation device 30 in the seedling planting device 5 is changed up and down.

[0201] If the planting depth rod 42 is operated so that the set depth B1 of the seedling (refer to Figure 5 and Figure 6 ) is changed, then the height from the field surface G to the land preparation device 30 (drive shaft 82) is detected based on the detection value of the planting depth sensor 113 and the detection value of the height sensor 111.

[0202] Similarly to the above, the electric motor 109 operates in such a manner that the height from the field surface G to the land preparation device 30 (drive shaft 82) becomes the land preparation set height A2 (land preparation depth) set (changed) by the height adjustment switch 112, and the support position of the land preparation device 30 in the seedling planting device 5 is changed up and down.

[0203] Thus, even if the planting depth rod 42 is operated so that the set depth B1 of the seedling (refer to Figure 5 and Figure 6 ) is changed, the height from the field surface G to the land preparation device 30 (drive shaft 82) is maintained at the land preparation set height A2 (land preparation depth) set (changed) by the height adjustment switch 112.

[0204] (First other embodiment of the invention)

[0205] Alternatively, the recesses 97 and 98 may be abolished on the upper surface portion 92a of the second portion 92 of the central floating plate 17.

[0206] Alternatively, instead of providing the recesses 99 with a larger lateral width toward the front side in the left - right direction on the lower surface portions 92b, 92c and the connecting portion 92d of the second portion 92 of the central floating plate 17, recesses 99 may be provided having the same lateral width in the left - right direction at the front and the rear, similar to the recess 100.

[0207] (Second other embodiment of the invention)

[0208] In the central floating plate 17, it may be configured such that the lateral widths W22 and W23 shown in Figure 12 are set to be slightly smaller than the lateral width W11, and the lateral width W21 is larger than twice the value of the lateral width W11 and smaller than three times the value of the lateral width W11.

[0209] It can also be configured such that the length L2 is longer than the length L1.

[0210] (The third other embodiment of the invention)

[0211] The side floating plates 18 and 19 can also adopt Figures 12 - 15 the structure of the central floating plate 17 shown. In this case, the side floating plates 18 and 19 can also adopt the structures described in the above other embodiments (the first other embodiment of the invention) (the second other embodiment of the invention).

[0212] (The fourth other embodiment of the invention)

[0213] In the central floating plate 17 as described in the above other embodiment (the second other embodiment of the invention), Figure 12 when the lateral width W21 shown is larger than twice the value of the lateral width W11 and smaller than three times the value of the lateral width W11, it can also be that the transplanting depth rod 42 (the floating plate position changing part) is provided outside the range of the lateral width W21 in the left - right direction of the second part 92 in the front view.

[0214] Similarly, it can also be that the soil preparation lifting mechanism 105 (the soil preparation device position changing part) is provided outside the range of the lateral width W21 in the left - right direction of the second part 92 of the central floating plate 17 in the front view.

[0215] It can also be that the height detection part 50 is provided outside the range of the lateral width W21 in the left - right direction of the second part 92 of the central floating plate 17 in the front view.

[0216] (The fifth other embodiment of the invention)

[0217] In Figure 3 the support arms 41a, 41b, and 41c of the fulcrum member 41 shown, it can also be that the interval W1 and the interval W2 are the same value, and the interval W3 is a value smaller than the intervals W1 and W2.

[0218] It can also be that the intervals W1, W2, and W3 are mutually different values. In this case, the values of the intervals W1, W2, and W3 can also be set in such a way as to form the following relational expressions (1) to (4).

[0219] (1) Interval W1 > Interval W2 > Interval W3 (2) Interval W1 < Interval W2 < Interval W3

[0220] (3) Interval W1 > Interval W2 = Interval W3 (4) Interval W1 < Interval W2 = Interval W3

[0221] (The sixth other embodiment of the invention)

[0222] In the support arms 41a and 41b of the fulcrum member 41, it is also possible that, similar to Figure 10 and Figure 11 the support arm 41c of the fulcrum member 41 shown, the first member 39 is connected so as to straddle the rear portions of the support arms 41a and 41b of the fulcrum member 41, and the second member 40 is connected so as to straddle the portions of the support arms 41a and 41b of the fulcrum member 41 that are closer to the fulcrum member 41 than the first member 39. It is also possible that the second member 40 is connected so as to straddle the transverse portions of the support arms 41a and 41b of the fulcrum member 41.

[0223] (Seventh Other Embodiment of the Invention)

[0224] In the support arms 41b and 41c of the fulcrum member 41, when the second member 40 is connected so as to straddle the transverse portions of the support arms 41b and 41c of the fulcrum member 41, as Figure 20 shown, it can also be configured such that the open portion of the second member 40 faces rearward.

[0225] With the above structure, the open portion of the second member 40 faces rearward.

[0226] In the support arm 41a of the fulcrum member 41, when the second member 40 is connected so as to straddle the transverse portion of the support arm 41a of the fulcrum member 41, as Figure 20 shown, it can also be configured such that the open portion of the second member 40 faces rearward.

[0227] In the support arms 41a, 41b, and 41c of the fulcrum member 41, when the second member 40 is connected so as to straddle the transverse portions of the support arms 41a, 41b, and 41c of the fulcrum member 41, it can also be configured such that the open portion of the second member 40 faces rearward.

[0228] (Eighth Other Embodiment of the Invention)

[0229] In Figure 5 and Figure 6 the limiting portion 48 of the height detection unit 50 shown, it is also possible to set an upper limit position and abolish the lower limit position, and it is also possible to set a lower limit position and abolish the upper limit position. In the limiting mechanism 67, it is also possible to set an upper limit position and abolish the lower limit position, and it is also possible to set a lower limit position and abolish the upper limit position.

[0230] In the above structure, it can also be configured to form the combinations described in (1) to (6) below.

[0231] (1) Set an upper limit position and abolish the lower limit position in the limiting portion 48 of the height detection unit 50. Set an upper limit position and abolish the lower limit position in the limiting mechanism 67.

[0232] (2) Abolish the upper limit position and set the lower limit position in the restricting part 48 of the height detecting part 50. Abolish the upper limit position and set the lower limit position in the restricting mechanism 67.

[0233] (3) Set the upper limit position and abolish the lower limit position in the restricting part 48 of the height detecting part 50. Abolish the upper limit position and set the lower limit position in the restricting mechanism 67.

[0234] (4) Abolish the upper limit position and set the lower limit position in the restricting part 48 of the height detecting part 50. Set the upper limit position and abolish the lower limit position in the restricting mechanism 67.

[0235] (5) Set one of the upper limit position and the lower limit position in the restricting part 48 of the height detecting part 50. Set both the upper limit position and the lower limit position in the restricting mechanism 67.

[0236] (6) Set both the upper limit position and the lower limit position in the restricting part 48 of the height detecting part 50. Set one of the upper limit position and the lower limit position in the restricting mechanism 67.

[0237] (The ninth other embodiment of the invention)

[0238] In the height detecting part 50 and the restricting mechanism 67, the height detecting part 50 may be provided on the left part of the second part 92 of the central floating plate 17, and the restricting mechanism 67 may be provided on the right part of the second part 92 of the central floating plate 17.

[0239] (The tenth other embodiment of the invention)

[0240] In the seedling planting device 5, it may also be configured that the rotating box 15 is abolished, and one planting arm 16 is rotatably supported on the right part of the planting transmission box 14, and one planting arm 16 is rotatably supported on the left part of the planting transmission box 14.

[0241] Alternatively, instead of the seedling planting device 5, a seeding device (not shown) for supplying rice seeds to the paddy field surface G may be provided as the working device.

[0242] Industrial applicability

[0243] The present invention can be applied to a paddy field working machine in which a working device such as a seedling planting device and a seeding device is liftably supported at the rear part of a machine body supported by traveling wheels.

[0244] Explanation of reference numerals

[0245] 1: Front wheel (wheel); 2: Rear wheel (wheel); 3: Machine body; 5: Seedling planting device (working device); 14: Planting transmission case; 16: Planting arm; 17: Central floating plate (floating plate); 20: Seedling table; 30: Land preparation device; 41: Fulcrum member; 41a: Support arm; 42: Planting depth rod (floating plate position changing part); 48: Restriction part; 50: Height detection part; 59: Assembly member (part supported to swing up and down); 64: Support member; 65: Restriction pin; 66: Restriction link; 66a: Long hole; 67: Restriction mechanism; 71: Lifting control part; 90: Connection part (part); 91: First part; 91b: Lower surface part; 92: Second part; 92a: Upper surface part; 92b: Lower surface part; 92c: Lower surface part; 97: Concave part (upper concave part); 99: Concave part (lower concave part); 101: Assembly part; 105: Land preparation device position changing part; A1: Set height; G: Field surface; L1: Length; L2: Length; W11: Lateral width; W21: Lateral width; W22: Lateral width; W23: Lateral width; θ1: Front raising angle; θ2: Front raising angle.

Claims

1. A paddy field working machine, characterized in that, Comprising: A body supported by wheels for traveling; An operating device supported in a liftable manner at the rear of the body; A floating plate supported in an oscillatable manner up and down at the lower part of the operating device, following the ground surface of the paddy field; A height detection unit for detecting the height of the operating device from the floating plate; A lift control unit for lifting and lowering the operating device relative to the body based on the detection by the height detection unit so as to maintain the operating device at a preset height from the ground surface of the paddy field; And A restricting mechanism provided separately from the height detection unit for restricting at least one of the upper limit position and the lower limit position of the up-and-down oscillation of the floating plate relative to the operating device.

2. The paddy field working machine according to claim 1, wherein The height detection unit is provided at a part on one side of the right side and the left side of the floating plate relative to the part supported in an oscillatable manner up and down by the operating device, The restricting mechanism is provided at a part on the other side of the right side and the left side of the floating plate relative to the part supported in an oscillatable manner up and down by the operating device.

3. The paddy field working machine according to claim 1 or 2, wherein The floating plate has: a first part supported in an oscillatable manner up and down by the operating device; and a second part connected to the front part of the first part, and the lateral width of the second part in the left-right direction is larger than the lateral width of the first part in the left-right direction, The height detection unit is provided at one of the right part and the left part of the second part, The restricting mechanism is provided at the other of the right part and the left part of the second part.

4. The paddy field working machine according to any one of claims 1 to 3, wherein The height detection unit is provided at the front part of the floating plate and is provided on the front side of the restricting mechanism in a side view.

5. The paddy field working machine according to any one of claims 1 to 4, wherein Comprising: a fulcrum member supported at the lower part of the operating device along the left-right direction; and a support arm connected to the fulcrum member and extending obliquely rearward and downward, The floating plate is supported at the rear part of the support arm in a manner capable of oscillating up and down about an axis along the left-right direction, The height detection unit is provided on the front side of the fulcrum member in a side view, The restricting mechanism is provided on the rear side of the fulcrum member in a side view.

6. The paddy field working machine according to any one of claims 1 to 5, wherein The height detection unit has a restricting part for restricting at least one of the upper limit position and the lower limit position of the floating plate relative to the operating device.

7. The paddy field working machine according to any one of claims 1 to 5, wherein The height detection unit has a restricting part for restricting both the upper limit position and the lower limit position of the floating plate relative to the operating device, The restricting mechanism restricts both the upper limit position and the lower limit position of the up-and-down oscillation of the floating plate relative to the operating device.

8. The paddy field working machine according to claim 7, wherein The limiting mechanism has: a limiting pin supported by the working device; a limiting link supported by the floating plate so as to be swingable about an axis along the left-right direction; and a long hole opening along the long dimension direction of the limiting link, into which the limiting pin is inserted. When the limiting pin reaches one end of the long hole, the floating plate is limited to the upper limit position by the limiting mechanism. When the limiting pin reaches the other end of the long hole, the floating plate is limited to the lower limit position by the limiting mechanism.

9. The paddy field working machine according to claim 8, wherein the limiting mechanism has a support member on the right side and a support member on the left side supported by the working device. The limiting pin is assembled so as to straddle the support member on the right side and the support member on the left side.

10. The paddy field working machine according to any one of claims 7 to 9, wherein the upper limit position of the limiting mechanism is set above the upper limit position of the limiting portion, and the lower limit position of the limiting mechanism is set below the lower limit position of the limiting portion.

11. The paddy field working machine according to any one of claims 1 to 10, wherein the working device is a seedling transplanting device, and the seedling transplanting device has: a seedling stage on which seedlings are placed; a transplanting arm that takes out seedlings from the seedling stage and transplants them onto the paddy field surface; and a transplanting transmission case that supports the transplanting arm on its lateral side portion. The transplanting transmission case is arranged at a position deviated in the left-right direction from a position above the limiting mechanism.

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