1. A paddy field work machine comprising: a body supported by travel wheels; a work device elevatably supported by a rear section of the body; and a float supported by a lower section of the work device in such a manner as to be swingable up and down, and configured to follow a ground surface in contact therewith, wherein the float includes: a first portion supported by a lower section of the work device; and a second portion connected to a front portion of the first portion and extending obliquely forward and upward from the front portion of the first portion in a side view, and the second portion has a lower face portion angled relative to a lower face portion of the first portion by a forward rising angle greater than a forward rising angle of an upper face portion of the second portion relative to the lower face portion of the first portion in a side view.

2. The paddy field work machine according to claim 1, wherein the second portion includes: a portion corresponding to a mating portion of a pair of molds in blow molding; and an intermediate portion located between the upper face portion of the second portion and the lower face portion of the second portion, and the portion of the second portion corresponding to the mating portion is located closer to the lower face portion of the second portion than the intermediate portion is, in a side view.

3. The paddy field work machine according to claim 1 or 2, wherein the upper face portion of the second portion extends obliquely forward and upward from a front portion of an upper face portion of the first portion in a side view, the lower face portion of the second portion includes: a first lower face portion extending forward from the lower face portion of the first portion in parallel with the lower face portion of the first portion in a side view; and a second lower face portion extending obliquely forward and upward from a front portion of the first lower face portion in a side view, and the second lower face portion of the second portion is angled relative to the lower face portion of the first portion by a forward rising angle greater than the forward rising angle of the upper face portion of the second portion relative to the lower face portion of the first portion in a side view.

4. The paddy field work machine according to anyone of claims 1-3, wherein the upper face portion of the second portion includes an upper recess recessed from the upper face portion of the second portion toward the lower face portion of the second portion, and the upper recess extends in a front-rear direction and has a depth, from the upper face portion of the second portion, that decreases as the upper recess extends rearward.

5. The paddy field work machine according to anyone of claims 1-4, wherein the lower face portion of the second portion includes a lower recess recessed from the lower face portion of the second portion toward the upper face portion of the second portion, and the lower recess extends in a front-rear direction and has a left-right width that increases as the lower recess extends forward.

6. The paddy field work machine according to anyone claims 1-5, wherein the second portion has a left-right width greater than two times a left-right width of the first portion.

7. The paddy field work machine according to claim 6, wherein the first portion has a right end portion and a left end portion, the second portion has a right end portion and a left end portion, the right end portion of the first portion is separated from the right end portion of the second portion by a left-right distance greater than the left-right width of the first portion, and the left end portion of the first portion is separated from the left end portion of the second portion by a left-right distance greater than the left-right width of the first portion.

8. The paddy field work machine according to anyone of claims 1-7, wherein the second portion has a front-rear length shorter than a front-rear length of the first portion.

9. The paddy field work machine according to anyone of claims 1-8, further comprising: a float position changing section configured to change, in an up-down direction, a support position at which the float is supported by the lower section of the work device, wherein the float position changing section is within a range of the left-right width of the second portion in a front view.

10. The paddy field work machine according to anyone of claims 1-9, further comprising: a leveler supported by the work device, located in front of the float, and configured to level the ground surface; and a leveler position changing section configured to change, in an up-down direction, a support position at which the leveler is supported by the work device, wherein the leveler position changing section is within a range of the left-right width of the second portion in a front view.

11. The paddy field work machine according to anyone of claims 1-10, further comprising: a height detector configured to detect a height of the work device from the float; and an elevation control unit configured to raise and lower the work device relative to the body based on the height detected by the height detector, in such a manner that the height of the work device is maintained at a predetermined set height from the ground surface, wherein the second portion includes, in a front end portion, an attachment portion extending to a position below the upper face portion of the second portion in a side view, and the height detector is attached to the attachment portion.

Description:DESCRIPTION

Technical Field
[0001] The present invention relates to a paddy field work machine having a work device, such as a seedling planting device or a seeding device, that is supported by a rear section of a body supported by travel wheels.

Background Art
[0002] In a riding type of rice transplanter, which is an example of a paddy field work machine, as disclosed in Patent Document 1, a float is supported by the bottom section of a seedling planting device (corresponding to a work device) so as to be capable of swinging up and down, and the float follows the ground surface in contact therewith.

Prior Art Document
Patent Document
[0003] Patent Document 1: JP 2022-85191A

Disclosure of the Invention
Problem to be Solved by the Invention
[0004] In this paddy field work machine, the float supported by the bottom section of the work device has functions such as leveling the ground surface and stabilizing the posture of the work device, and in recent years, there has been demand for an improvement in the ground leveling function of the float.
[0005] An object of the present invention is to improve the ground leveling function of a float supported by a work device in a paddy field work machine.

Means for Solving Problem
[0006] A paddy field work machine according to an aspect of the present invention includes: a body supported by travel wheels; a work device elevatably supported by a rear section of the body; and a float supported by a lower section of the work device in such a manner as to be swingable up and down, and configured to follow a ground surface in contact therewith, wherein the float includes: a first portion supported by a lower section of the work device; and a second portion connected to a front portion of the first portion and extending obliquely forward and upward from the front portion of the first portion in a side view, and the second portion has a lower face portion angled relative to a lower face portion of the first portion by a forward rising angle greater than a forward rising angle of an upper face portion of the second portion relative to the lower face portion of the first portion in a side view.
[0007] The float, which is supported by a lower section of the work device and swings up and down so as to follow the ground surface in contact therewith, includes the first portion that is supported by the lower section of the work device and the second portion that extends obliquely forward and upward from a front portion of the first portion, and thus as the body travels forward, mud at the ground surface enters the region below the lower face portion of the second portion of the float, and the ground surface is leveled by the lower face of the second portion of the float.
[0008] According to the above aspect of the present invention, regarding the upper face portion and the lower face portion of the second portion of the float, the forward rising angle of the lower face portion of the second portion of the float is set greater than the forward rising angle of the upper face portion of the second portion of the float.
Accordingly, as the body travels forward, a large amount of mud at the ground surface is likely to enter the region below the lower face portion of the second portion of the float, and it is possible to avoid a reduction in the amount of mud from the ground surface that enters the region below the lower face portion of the second portion of the float, thus making it possible to improve the ground leveling function of the float.
[0009] In an aspect of the present invention, it is preferable that the second portion includes: a portion corresponding to a mating portion of a pair of molds in blow molding; and an intermediate portion located between the upper face portion of the second portion and the lower face portion of the second portion, and the portion of the second portion corresponding to the mating portion is located closer to the lower face portion of the second portion than the intermediate portion is, in a side view.
[0010] The float of a paddy field work machine is often manufactured by blow molding.
According to the above aspect of the present invention, in the second portion of the float, the portion corresponding to the mating portion of the pair of molds in blow molding is located closer to the lower face portion of the second portion of the float, and therefore the lower face portion of the second portion of the float can be easily molded into a relatively flat shape rather than bulging downward in a side view.
This makes it possible to reduce the amount of mud at the ground surface that escapes laterally from the lower face portion of the second portion of the float when the body travels forward, which is advantageous in terms of improving the ground leveling function of the float.
[0011] In an aspect of the present invention, it is preferable that the upper face portion of the second portion extends obliquely forward and upward from a front portion of an upper face portion of the first portion in a side view, the lower face portion of the second portion includes: a first lower face portion extending forward from the lower face portion of the first portion in parallel with the lower face portion of the first portion in a side view; and a second lower face portion extending obliquely forward and upward from a front portion of the first lower face portion in a side view, and the second lower face portion of the second portion is angled relative to the lower face portion of the first portion by a forward rising angle greater than the forward rising angle of the upper face portion of the second portion relative to the lower face portion of the first portion in a side view.
[0012] According to this aspect of the present invention, the lower face portion of the second portion of the float includes the first lower face portion that extends forward from, and in parallel with, the lower face portion of the first portion of the float, and the second lower face portion that extends obliquely forward and upward from the front portion of the first lower face portion of the float.
Accordingly, as the body travels forward, mud from the ground surface that has entered the region below the second lower face portion of the second portion of the float is easily smoothed by the first lower face portion of the second portion of the float, which is advantageous in terms of improving the ground leveling function of the float.
[0013] The upper face portion of the second portion of the float extends obliquely forward and upward from the front portion of the upper face portion of the first portion of the float, relative to the first and second lower face portions of the second portion of the float.
Accordingly, mud on the upper face portion of the second portion of the float is likely to move rearward along the upper face portion of the second portion of the float, and is likely to reach the rear end portion of the upper face portion of the second portion of the float and return to the paddy surface, thus making it possible to avoid the case where the swinging up and down of the float is hindered by mud that has accumulated on the upper face portion of the second portion of the float, which is advantageous in terms of improving the ground leveling function of the float.
[0014] In an aspect of the present invention, it is preferable that the upper face portion of the second portion includes an upper recess recessed from the upper face portion of the second portion toward the lower face portion of the second portion, and the upper recess extends in a front-rear direction and has a depth, from the upper face portion of the second portion, that decreases as the upper recess extends rearward.
[0015] According to this aspect of the present invention, the upper recess is provided in the upper face portion of the second portion of the float and extends along the front-rear direction. The depth of the upper recess becomes shallower as the upper recess extends rearward, and the bottom portion of the upper recess follows the lower face portion of the first portion of the float in a side view.
Accordingly, mud on the upper face portion of the second portion of the float is likely to accumulate in the upper recess, move rearward from the upper recess, and return from the upper recess to the paddy surface, which is advantageous in terms of improving the ground leveling function of the float.
[0016] In an aspect of the present invention, it is preferable that the lower face portion of the second portion includes a lower recess recessed from the lower face portion of the second portion toward the upper face portion of the second portion, and the lower recess extends in a front-rear direction and has a left-right width that increases as the lower recess extends forward.
[0017] According to this aspect of the present invention, the lower recess, whose left-right width increases as the lower recess extends forward, is provided in the lower face portion of the second portion of the float.
Accordingly, as the body travels forward, mud at the ground surface is collected by the lower recess and likely to enter the region below the lower face portion of the second portion of the float, and it is possible to avoid a reduction in the amount of mud from the ground surface that enters the region below the lower face portion of the second portion of the float, which is advantageous in terms of improving the ground leveling function of the float.
[0018] In an aspect of the present invention, it is preferable that the second portion has a left-right width greater than two times a left-right width of the first portion.
[0019] According to this aspect of the present invention, the second portion of the float has a large left-right width, and a larger region is leveled by the second portion of the float, which is advantageous in terms of improving the ground leveling function of the float.
[0020] In an aspect of the present invention, it is preferable that the first portion has a right end portion and a left end portion, the second portion has a right end portion and a left end portion, the right end portion of the first portion is separated from the right end portion of the second portion by a left-right distance greater than the left-right width of the first portion, and the left end portion of the first portion is separated from the left end portion of the second portion by a left-right distance greater than the left-right width of the first portion.
[0021] According to this aspect of the present invention, the second portion of the float has a large left-right width, and a larger region is leveled by the second portion of the float, which is advantageous in terms of improving the ground leveling function of the float.
[0022] In an aspect of the present invention, it is preferable that the second portion has a front-rear length shorter than a front-rear length of the first portion.
[0023] According to this aspect of the present invention, in the case where the second portion of the float has a large left-right width, the front-rear length of the second portion of the float is relatively short, thus making it possible to suppress an increase in the size and weight of the float overall.
[0024] In an aspect of the present invention, it is preferable that the paddy field work machine further includes a float position changing section configured to change, in an up-down direction, a support position at which the float is supported by the lower section of the work device, and the float position changing section is within a range of the left-right width of the second portion in a front view.
[0025] In the case where the float is supported by a lower section of the work device, the paddy field work machine can be provided with a float position changing section that can change, in the up-down direction, the support position at which the float is supported by the lower section of the work device.
According to the above aspect of the present invention, in the case where the second portion of the float has a large left-right width, the float position changing section is provided within the range of the left-right width of the second portion of the float in a front view, this making it possible to reduce the overall size of the float and the float position changing section.
[0026] In an aspect of the present invention, it is preferable that the paddy field work machine further includes: a leveler supported by the work device, located in front of the float, and configured to level the ground surface; and a leveler position changing section configured to change, in an up-down direction, a support position at which the leveler is supported by the work device, and the leveler position changing section is within a range of the left-right width of the second portion in a front view.
[0027] In the paddy field work machine, the leveler for leveling the ground surface is sometimes supported by the work device at a location in front of the float, and the ground leveling function can sometimes be improved by the float and the leveler. In this case, it is possible to provide the leveler position changing section that can change, in the up-down direction, the support position at which the leveler is supported by the work device.
[0028] According to the above aspect of the present invention, in the case where the second portion of the float has a large left-right width, the leveler position changing section is provided within the range of the left-right width of the second portion of the float in a front view, this making it possible to reduce the overall size of the float and the leveler position changing section.
[0029] In an aspect of the present invention, it is preferable that the paddy field work machine further includes: a height detector configured to detect a height of the work device from the float; and an elevation control unit configured to raise and lower the work device relative to the body based on the height detected by the height detector, in such a manner that the height of the work device is maintained at a predetermined set height from the ground surface, the second portion includes, in a front end portion, an attachment portion extending to a position below the upper face portion of the second portion in a side view, and the height detector is attached to the attachment portion.
[0030] In the paddy field work machine, the float follows the ground surface in contact therewith, and thus the height from the float to the work device is the height from the ground surface to the work device.
In this case, it is possible to provide the height detector that detects the height of the work device from the float, and provide the elevation control unit that raises and lowers the work device relative to the body based on the height detected by the height detector such that the height of the work device is maintained at a predetermined set height from the ground surface.
[0031] According to this aspect of the present invention, the front end portion of the second portion of the float includes the attachment portion that extends to a position below the upper face portion of the second portion of the float in a side view, and the height detector is attached to the attachment portion of the float.
[0032] Accordingly, as the body travels forward, even if mud from the ground surface attempts to move over the front end portion of the second portion of the float and remain on the upper face portion of the second portion of the float, the attachment portion of the front end portion of the float makes it unlikely for the mud from the ground surface to move over the front end portion of the second portion of the float, thus making it possible to avoid a reduction in the amount of mud from the ground surface that enters the region below the lower face portion of the second portion of the float, which is advantageous in terms of improving the ground leveling function of the float.

Brief Description of the Drawings
[0033] FIG. 1 is a left side view of a riding type of rice transplanter.
FIG. 2 is a plan view of a seedling planting device and a leveler.
FIG. 3 is a plan view showing a structure for supporting a center float and side floats.
FIG. 4 is a front view of a region including the center float.
FIG. 5 is a left side view of a region including the center float.
FIG. 6 is a left side view of a region including the center float.
FIG. 7 is a left side view of a region including a rear portion of the center float.
FIG. 8 is a plan view of a region including a rear portion of the center float.
FIG. 9 is a left side view of a region including a side float.
FIG. 10 is a left side view of a region including a side float.
FIG. 11 is a plan view showing a structure for supporting a side float.
FIG. 12 is a plan view of the center float.
FIG. 13 is a bottom view of the center float.
FIG. 14 is a front view of the center float.
FIG. 15 is a left side view of the center float.
FIG. 16 is a left side view showing a structure for raising and lowering the leveler.
FIG. 17 is a plan view of a guide section.
FIG. 18 is a cross-sectional view of the guide section.
FIG. 19 is a schematic diagram showing interlinking of a control device with various sections.
FIG. 20 is a left side view of a region including a side float in a seventh variation of the invention.

Best Mode for Carrying out the Invention
[0034] FIGS. 1 to 20 show a riding type of rice transplanter, which is an example of a paddy field work machine, and in FIGS. 1 to 20, F indicates the front direction, B indicates the rear direction, U indicates the upward direction, D indicates the downward direction, R indicates the right direction, and L indicates the left direction.
[0035] Overall configuration of riding type of rice transplanter
As shown in FIG. 1, a body 3 is supported by right and left front wheels 1 (corresponding to travel wheels) and right and left rear wheels 2 (corresponding to travel wheels). A link mechanism 4 extends rearward from a rear section of the body 3, and a seedling planting device 5 (corresponding to a work device) is supported by a rear portion of the link mechanism 4. A fertilizing device 6 is supported by the rear portion of body 3, and a leveler 30 is supported by a front portion of the seedling planting device 5. When a hydraulic cylinder 7 extends and retracts, the link mechanism 4 is raised and lowered, and the seedling planting device 5 is raised and lowered by the link mechanism 4. The link mechanism 4 and the rear section of the body 3 are coupled to each other by the hydraulic cylinder 7. A driver seat 8 and a steering wheel 9 for steering the front wheels 1 are provided in the body 3. Right and left support frames 10 are coupled to right and left sections of a front section of the body 3 and extend upward, and a spare seedling stand 11 is attached to the support frames 10.
[0036] Overall configuration of seedling planting device
As shown in FIGS. 1, 2, and 3, the seedling planting device 5 is configured for 8-row planting and includes a feed case 12, a support frame 13, planting transmission cases 14, rotation cases 15, planting arms 16, a center float 17 (corresponding to a float), side floats 18 and 19 (each corresponding to a float), and a seedling stand 20. The feed case 12 is supported by a lower portion of a rear portion of the link mechanism 4, and the square pipe-shaped support frame 13 is coupled to the feed case 12 and extends along the left-right direction. Four planting transmission cases 14 are coupled to the support frame 13 and extend rearward. The rotation cases 15 are rotatably supported by right sections and left sections of rear portions of the planting transmission cases 14, and pairs of planting arms 16 are attached to the rotation cases 15. The seedling stand 20, on which seedlings are placed, is supported by the planting transmission cases 14 so as to be capable of moving back and forth in the left-right direction. As the body 3 travels forward, the leveler 30 levels a ground surface G (see FIG. 5). In the seedling planting device 5, the rotation cases 15 are driven to rotate while the seedling stand 20 moves back and forth along the left-right direction, and the planting arms 16 retrieve seedlings from the seedling stand 20 and plant the seedlings in the ground surface G.
[0037] Configuration of transmission system for rotation cases in seedling planting device
As shown in FIG. 2, motive power from an engine (not shown) mounted in the body 3 is transmitted via a transmission shaft 26 (see FIG. 1) to an input shaft 27 inside the feed case 12. An output shaft 28 is provided in a lower portion of the feed case 12, and the motive power transmitted to the input shaft 27 is transmitted to the output shaft 28 via a transmission chain 29.
[0038] Motive power is transmitted from the output shaft 28 of the feed case 12 to drive shafts 35 via transmission shafts 32 (housed inside a tubular cover 37), input shafts 31, torque limiters 33, transmission chains 34, and low-number row clutches 36, and thus the drive shafts 35 are driven to rotate, and the rotation cases 15 and the planting arms 16 are driven to rotate in the counterclockwise direction in FIG. 1.
[0039] Overall configuration of fertilizing device
As shown in FIGS. 1 and 3, the fertilizing device 6 includes a hopper 21, a feeding section 22, a blower 23, groove cutters 24, and hoses 25. As the body 3 travels forward, fertilizer in the hopper 21 is fed to the hoses 25 by the feeding section 22, the blower 23 supplies air to the hoses 25, and the fertilizer is supplied to the groove cutters 24 via the hoses 25. As the body 3 travels forward, grooves are formed in the ground surface G (see FIG. 5) by the groove cutters 24, the fertilizer supplied to the groove cutters 24 is supplied from the groove cutters 24 to the grooves in the ground surface G, and then the grooves in the ground surface G are filled by soil covering members 38.
[0040] Configuration of support arm of fulcrum member
As shown in FIGS. 3, 4, and 5, the seedling planting device 5 (work device) includes a fulcrum member 41 that extends in the left-right direction and is supported by a lower portion of the seedling planting device 5 (work device), pairs of support arms 41a, 41b, and 41c that are coupled to the fulcrum member 41 and extend obliquely downward and rearward, and a center float 17 (float) and side floats 18 and 19 (floats) that follow the ground surface G in contact therewith due to being supported by rear portions of the pairs of support arms 41a, 41b, and 41c so as to be capable of swinging up and down about an axis P2 along the left-right direction.
[0041] As shown in FIG. 3, the pair of support arms 41a of the fulcrum member 41 are separated by a distance W1 in the left-right direction, the pair of support arms 41b of the fulcrum member 41 are separated by a distance W2 in the left-right direction, and the pair of support arms 41c of the fulcrum member 41 are separated by a distance W3 in the left-right direction; the distance W1 and the distance W2 are the same distance, and the distance W3 is larger than the distances W1 and W2.
[0042] As shown in FIGS. 3, 7, 8, and 9, upper face portions of longitudinal central portions of the pair of support arms 41a of the fulcrum member 41 are coupled to each other by a flat plate-shaped first member 39, and upper face portions of longitudinal central portions of each pair of support arms 41b of the fulcrum member 41 are coupled to each other by a flat plate-shaped first member 39. Upper face portions of rear portions of the pair of support arms 41a of the fulcrum member 41 are coupled to each other by a channel-shaped second member 40, and upper face portions of rear portions of each pair of support arms 41b of the fulcrum member 41 are coupled to each other by a channel-shaped second member 40.
[0043] As shown in FIGS. 3, 10, and 11, upper face portions of rear portions of each pair of support arms 41c of the fulcrum member 41 are coupled to each other by a flat plate-shaped first member 39.
[0044] Longitudinal central portions of each pair of support arms 41c of the fulcrum member 41 are coupled to each other by a channel-shaped second member 40, and the open portions of the second members 40 are open forward. Lateral face portions of the corresponding pair of support arms 41c of the fulcrum member 41 are coupled to each other by the second members 40, and the second members 40 do not extend upward or downward beyond upper ends or lower ends of the support arm 41c of the fulcrum member 41 in a side view (see FIG. 10).
[0045] According to the above configuration, as shown in FIG. 3, the distance W1 in the left-right direction between the pair of support arms 41a located in the lateral central portion of the seedling planting device 5 (work device) is different from the distance W3 in the left-right direction between each pair of support arms 41c located in the right and left portions of the seedling planting device 5 (work device).
[0046] The distance W3 in the left-right direction between each pair of support arms 41c located in the right and left portions of the seedling planting device 5 (work device) is greater than the distance W1 in the left-right direction between the pair of support arms 41a located in the lateral central portion of the seedling planting device 5 (work device).
[0047] As shown in FIGS. 10 and 11, rear portions of each pair of support arms 41c of the fulcrum member 41 are coupled to each other by a flat plate-shaped first member 39, and portions of each pair of support arms 41c on the fulcrum member 41 side of the first member 39 are coupled to each other by a channel-shaped second member 40. Lateral face portions of each pair of support arms 41c of the fulcrum member 41 are coupled to each other by the second member 40.
[0048] Center float configuration: 1
The center float 17 is manufactured by blow molding, and includes a first portion 91, which is the rear portion, and a second portion 92, which is the front portion, as shown in FIGS. 12 to 15. The right portion of the second portion 92 is located below a planting depth lever 42 and a guide section 43 (see FIG. 4).
[0049] As shown in FIGS. 12 and 15, the center float 17 (float) includes the first portion 91 supported by a lower portion of the seedling planting device 5 (work device), and the second portion 92 that is connected to a front portion of the first portion 91 and extends obliquely forward and upward from the front portion of the first portion 91 in a side view.
[0050] A left-right width W21 of the second portion 92 is greater than two times (three times) a left-right width W11 of the first portion 91.
A left-right width W22 between a right end portion of the first portion 91 and a right end portion of the second portion 92 is greater than the left-right width W11 of the first portion 91, and a left-right width W23 between a left end portion of the first portion 91 and a left end portion of the second portion 92 is greater than the left-right width W11 of the first portion 91.
A front-rear length L2 of the second portion 92 is shorter than a front-rear length L of the first portion 91.
As shown in FIG. 4, the planting depth lever 42 (float position changing section) is provided within the range of the left-right width W21 of the second portion 92 in a front view.
[0051] Center float configuration: 2
As shown in FIGS. 12 to 15, in the center float 17, an upper face portion 91a and a lower face portion 91b of the first portion 91 are substantially parallel in a side view. An upper face portion 92a of the second portion 92 extends obliquely forward and upward from a front portion of the upper face portion 91a of the first portion 91 in a side view.
[0052] In the second portion 92 of the center float 17, a lower face portion 92b (corresponding to a first lower face portion) of the second portion 92 extends forward from, and in parallel with, a front portion of the lower face portion 91b of the first portion 91 in a side view.
[0053] A connection portion 92d of the second portion 92, which is arc-shaped in a side view, extends obliquely forward and upward from a front portion of the lower face portion 92b of the second portion 92 in a side view. A lower face portion 92c (corresponding to a second lower face portion) of the second portion 92 extends obliquely forward and upward from a front portion (upper portion) of the connection portion 92d of the second portion 92, in a side view.
[0054] As shown in FIG. 15, regarding the upper face portion 92a and the lower face portion 92c of the second portion 92, a forward rising angle ?1 of the lower face portion 92c of the second portion 92 relative to the lower face portion 91b of the first portion 91 is greater than a forward rising angle ?2 of the upper face portion 92a of the second portion 92 relative to the lower face portion 91b of the first portion 91 in a side view.
[0055] The upper face portion 92a of the second portion 92 extends obliquely forward and upward from a front portion of the upper face portion 91a of the first portion 91 in a side view.
In a side view, the lower face portions 92b and 92c of the second portion 92 include a first lower face portion 92b extending forward from, and in parallel with, the lower face portion 91b of the first portion 91, and a second lower face portion 92c extending obliquely forward and upward from a front portion of the first lower face portion 92b.
In a side view, the forward rising angle ?1 of the second lower face portion 92c of the second portion 92 relative to the lower face portion 91b of the first portion 91 is greater than the forward rising angle ?2 of the upper face portion 92a of the second portion 92 relative to the lower face portion 91b of the first portion 91.
[0056] The second portion 92 has a joint portion 90 (portion) corresponding to the mating portion of a pair of molds in blow molding, and an intermediate portion located between the upper face portion 92a and the lower face portions 92b and 92c, and the joint portion 90 (portion) is located closer to the lower face portions 92b and 92c of the second portion 92 than the intermediate portion is, in a side view.
[0057] Center float configuration: 3
As shown in FIGS. 12 to 15, in the center float 17, right and left recesses 93 that are recessed downward are provided in the upper face portion 92a of the second portion 92, and right and left recesses 94 that are recessed upward are provided in the connection portion 92d and the lower face portions 92b and 92c of the second portion 92.
[0058] The groove cutters 24 (see FIGS. 1, 3, 4) of the fertilizing device 6 are attached to the recesses 93 and 94 of the center float 17, and the soil covering members 38 (see FIGS. 3, 7, and 8) are attached to right and left portions of the first portion 91. A recess 98 that is recessed downward is provided in a right portion of the upper face portion 92a of the second portion 92, and the recess 98 is connected to the right recess 93.
[0059] A recess 95 that is recessed downward is provided in a left portion of the upper face portion 92a of the second portion 92, and a recess 96 that is recessed upward is provided in a left portion of the connection portion 92d and the lower face portion 92b of the second portion 92.
[0060] Recesses 97 (corresponding to upper recesses) that are recessed downward are provided in a portion between the right and left recesses 93 in the upper face portion 92a of the second portion 92, and in a portion on the right side of the right recess 93. The recesses 97 have an elongated shape in the front-rear direction in a plan view.
[0061] As shown in FIGS. 12 and 15, the upper face portion 92a of the second portion 92 is provided with the recesses 97 (upper recesses) that are recessed from the upper face portion 92a of the second portion 92 toward the lower face portions 92b and 92c of the second portion 92. The recesses 97 (upper recesses) extend along the front-rear direction, and the depth from the upper face portion 92a of the second portion 92 decreases as the recesses 97 extend rearward.
[0062] Center float configuration: 4
As shown in FIGS. 4, 13, and 14, in the center float 17, a recess 99 (corresponding to a lower recess) that is recessed upward is provided on the lower face portions 92b and 92c and the connection portion 92d of the second portion 92, and a recess 100 that is recessed upward is provided in the lower face portion 91b of the first portion 91.
[0063] The recess 100 extends along the front-rear direction from a rear portion of the recess 99 to a rear end portion of the lower face portion 91b of the first portion 91. The left-right width of the recess 100 is the same as the left-right width of the rear portion of the recess 99.
[0064] As shown in FIGS. 12 to 15, in a right portion of a front end portion of the second portion 92, the joint portion 90 is bent so as to be recessed downward from the upper face portion 92a of the second portion 92, and an attachment portion 101 that is recessed to a position below the upper face portion 92a of the second portion 92 is provided in the joint portion 90.
[0065] As shown in FIGS. 4, 13, and 14, the recess 99 (lower recess) that is recessed from the lower face portions 92b and 92c of the second portion toward the upper face portion 92a of the second portion 92 is provided in the lower face portions 92b and 92c of the second portion 92. The recess 99 (lower recess) extends along the front-rear direction, and the left-right width of the recess 99 (lower recess) increases toward the front.
[0066] As shown in FIGS. 12 to 15, the attachment portion 101 that is recessed to a position below the upper face portion 92a of the second portion 92 in a side view is provided in a front end portion of the second portion 92, and a height detector 50 is attached to the attachment portion 101.
[0067] Configuration for attachment of fulcrum member to support arm in center float: 1
As shown in FIGS. 7 and 8, an attachment member 59 is attached to the center float 17 (float). When the attachment member 59 is attached to a fulcrum shaft 63, the center float 17 (float) supported by rear portions of the pair of support arms 41a of the fulcrum member 41 so as to be capable of swinging up and down about the axis P2 via the fulcrum shaft 63.
[0068] The attachment member 59 has a rectangular shape in a plan view, and includes a base plate portion 59a attached to the center float 17 (float), and right and left lateral side portions 59b that extend upward from left and right portions of the base plate portion 59a and are attached to the fulcrum shaft 63.
[0069] Configuration for attachment of fulcrum member to support arm in center float: 2
As shown in FIGS. 5 and 6, a limiting mechanism 67 is attached to the fulcrum member 41 and the second portion 92 of the center float 17. The limiting mechanism 67 is provided leftward of the planting transmission case 14 located above the center float 17, and the planting transmission case 14 located above the center float 17 is located rightward of the region above the limiting mechanism 67.
[0070] The limiting mechanism 67 includes right and left support members 64, a limiting pin 65, and a limiting link 66. The right and left support members 64 are coupled to a portion of the fulcrum member 41 located above the center float 17, and extend obliquely rearward and downward from the fulcrum member 41. Upper portions of the right and left support members 64 are coupled to each other by a top plate (not shown), and the limiting pin 65 is attached to rear portions of right and left lateral side portions 64b of the support members 64.
[0071] A bracket 69 is attached to the recesses 95 and 96 (see FIGS. 12 and 13) of the second portion 92 of the center float 17. The limiting link 66 is formed by bending an elongated plate into a channel shape, and is supported by the bracket 69 so as to be capable of swinging up and down about an axis P3 along the left-right direction. An elongated hole 66a is formed along the lengthwise direction in the limiting link 66. The right and left support members 64 are arranged inside the limiting link 66, and the limiting pin 65 is inserted into the elongated hole 66a of the limiting link 66.
[0072] When the seedling planting device 5 descends relative to the center float 17 (when the center float 17 rises relative to the seedling planting device 5), the limiting link 66 swings downward. When the limiting pin 65 comes into contact with a front end portion of the elongated hole 66a of the limiting link 66, the rising of the center float 17 relative to the seedling planting device 5 is stopped (corresponding to a state in which the center float 17 is limited at an upper limit position relative to the seedling planting device 5).
[0073] When the seedling planting device 5 rises relative to the center float 17 (when the center float 17 descends relative to the seedling planting device 5), the limiting link 66 swings upward. When the limiting pin 65 comes into contact with a rear end portion of the elongated hole 66a of the limiting link 66, the descending of the center float 17 relative to the seedling planting device 5 is stopped (corresponding to a state in which the center float 17 is limited at a lower limit position relative to the seedling planting device 5).
[0074] Configuration for attachment of fulcrum member to support arm in side float: 1
As shown in FIGS. 10 and 11, an attachment member 60 is attached to a rear portion of the side float 19. The attachment member 60 includes a base plate portion 60a having a rectangular shape in a plan view, and right and left lateral side portions 60b extending upward from right and left portions of the base plate portion 60a.
[0075] A front end portion of the base plate portion 59a of the attachment member 60 protrudes forward from a front end portion of the lateral side portions 60b of the attachment member 60, and the front-rear length of the base plate portion 59a of the attachment member 60 is longer than the front-rear length of the lateral side portions 60b of the attachment member 60. Two locations on a front portion of the base plate portion 60a of the attachment member 60 are coupled to an upper face portion of a rear portion of the side float 19 by bolts 73.
[0076] The fulcrum shaft 63 is supported by lateral face portions of rear portions of the support arms 41c of the fulcrum member 41. The right and left lateral side portions 60b of the attachment member 60 are arranged between the support arms 41c of the fulcrum member 41, and the right and left lateral side portions 60b of the attachment member 60 attached to the fulcrum shaft 63 so as to be capable of swinging up and down about the axis P2.
[0077] A coil spring 74 is attached to the fulcrum shaft 63, and one end portion 74a of the spring 74 is in contact with a rear portion of the base plate portion 60a of the attachment member 60. A plurality of attachment holes 41d are formed in the support arms 41c of the fulcrum member 41, and another end portion 74b of the spring 74 is inserted into one of the attachment holes 41d.
[0078] The rear portion of the side float 19 is biased downward by the end portion 74a of the spring 74, and the side float 19 is biased forward and upward around the fulcrum shaft 63 (axis P2). The biasing force of the spring 74 can be changed by inserting the end portion 74b of the spring 74 into another attachment hole 41d of the support arm 41c of the fulcrum member 41.
As shown in FIG. 9, the side float 18 is also provided with a fulcrum shaft 63, an attachment member 60, and a spring 74 similar to those of the side float 19.
[0079] Configuration for attachment of fulcrum member to support arm in side float: 2
As shown in FIGS. 9, 10, and 11, a limiting pin 75 is attached to lateral face portions of the support arms 41b of the fulcrum member 41, and a limiting pin 75 is attached to lateral face portions of the support arms 41c of the fulcrum member 41. Stoppers 41e are attached to portions of the fulcrum member 41 located above the side floats 18 and 19.
[0080] Brackets 76 are attached to the side floats 18 and 19, and a limiting link 77 is supported by each of the brackets 76 so as to be capable of swinging up and down about an axis P7 along the left-right direction. An elongated hole 77a is formed in the limiting link 77 along the lengthwise direction, and the limiting pin 75 is inserted into the elongated hole 77a of the limiting link 77.
[0081] 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 portions of the side floats 18 and 19 come into contact with the stoppers 41e of the fulcrum member 41, and the rising of the side floats 18 and 19 relative to the seedling planting device 5 is stopped (corresponding to a state in which the side floats 18 and 19 are limited at an upper limit position relative to the seedling planting device 5).
[0082] When the seedling planting device 5 rises relative to the side floats 18 and 19 (when the side floats 18 and 19 descend relative to the seedling planting device 5), the limiting links 77 swing upward. When the limiting pins 75 come into contact with the rear end portions of the elongated holes 77a of the limiting links 77, the descending of the side floats 18 and 19 relative to the seedling planting device 5 is stopped (corresponding to a state in which the side floats 18 and 19 are limited at a lower limit position relative to the seedling planting device 5).
[0083] Configuration of planting depth lever
As shown in FIGS. 3, 4, and 8, a manually operable planting depth lever 42 (corresponding to a float position changing section) (corresponding to a height adjuster) is coupled to the fulcrum member 41 and extends obliquely forward and upward. The planting depth lever 42 is provided rightward of the link mechanism 4 (see FIG. 1), and is provided above a right portion of the second portion 92 of the center float 17, which will be described later.
[0084] The guide section 43 is coupled to the support frame 13 and is provided rightward of the link mechanism 4 (see FIG. 1). The planting depth lever 42 is inserted into the guide section 43 and guided by the guide section 43, and when the planting depth lever 42 is engaged with the guide section 43, the planting depth lever 42 is thus held at a desired position by the guide section 43. By engaging the planting depth lever 42 with the guide section 43, the position of the axis P2 can be fixed, and a set depth B1 for seedlings can be set.
[0085] Configuration of guide section
As shown in FIGS. 17 and 18, the guide section 43 includes a body portion 44 and an engagement member 45 (corresponding to a reinforcing member). The body portion 44 is obtained by bending a flat plate into a channel shape, and openings 44b and 44c are formed in an upper face portion 44a (corresponding to a reinforcing member) of the body portion 44.
[0086] The opening 44b of the body portion 44 has a rectangular shape in a plan view. The engagement member 45 is shaped as a flat plate and is thicker than the upper face portion 44a of the body portion 44. A rectangular opening 45a is formed in the engagement member 45, and a large number of protruding engagement portions 45b are provided on the right side portion of the opening 45a.
[0087] The planting depth lever 42 is inserted into the openings 44b and 45a of the guide section 43 (the body portion 44 and the engagement member 45), and is guided along the openings 44b and 45a of the guide section 43 (the body portion 44 and the engagement member 45). When the planting depth lever 42 is engaged with at least one of the engagement portions 45b of the guide section 43 (engagement member 45), the planting depth lever 42 is thus held by the guide section 43. By engaging the planting depth lever 42 with the guide section 43, the position of the axis P2 can be fixed, and a set depth B1 for seedlings can be set.
[0088] The opening 44c of the body portion 44 has a rectangular shape in a plan view, and a large number of protruding engagement portions 44d are provided on a left side portion of the opening 44c of the body portion 44.
A seedling amount lever 46 is inserted into the opening 44c of the guide section 43 (body portion 44) and guided along the opening 44c of the guide section 43 (body portion 44). When the seedling amount lever 46 is engaged with the engagement portion 44d of the guide section 43 (body portion 44), the seedling amount lever 46 is thus held by the guide section 43.
[0089] According to the above configuration, as shown in FIGS. 17 and 18, the reinforcing member (the upper face portion 44a and the engagement members 45 of the body portion 44) is provided in the portion (engagement portion 45b) of the guide section 43 that becomes engaged with the planting depth lever 42 (height adjuster). By providing the reinforcing member in this manner, strength can be maintained even when the number of engagement portions 45b is increased. Therefore, it is possible to not only apply the guide section 43 of the same size as a conventional guide section, but also increase the number of engagement portions 45b to enable more detailed adjustment of the planting depth.
[0090] Configuration regarding control of elevation of seedling planting device
As shown in FIGS. 4, 5, and 6, a height detector 50 is provided to detect the height from the center float 17 (float).
[0091] The height detector 50 is provided forward of the limiting mechanism 67 in a side view.
The fulcrum member 41 is supported by the lower portion of the seedling planting device 5 (work device) and extends along the left-right direction, the support arms 41a are coupled to the fulcrum member 41 and extend obliquely rearward and downward, and the center float 17 (float) is supported by rear portions of the support arms 41a of the fulcrum member 41 so as to be capable of swinging up and down about the axis P2 along the left-right direction.
The height detector 50 is provided forward of the fulcrum member 41 in a side view, and the limiting mechanism 67 is provided rearward of the fulcrum member 41 in a side view.
[0092] The height detector 50 includes a limiter 48 that limits at least either the upper limit position or the lower limit position of the center float 17 (float) relative to the seedling planting device 5 (work device).
The height detector 50 may include the limiter 48 that limits both the upper limit position and the lower limit position of the center float 17 (float) relative to the seedling planting device 5 (work device).
[0093] Control of elevation of seedling planting device: 1
As shown in FIG. 19, an elevation control unit 71 is provided as software in the control device 70. A control valve 49 is provided for supplying and discharging hydraulic oil to and from the hydraulic cylinder 7 (see FIG. 1) to extend and retract the hydraulic cylinder 7, and the control valve 49 is operated by the elevation control unit 71.
[0094] In the state shown in FIG. 5, the planting depth lever 42 is operated to the frontmost position relative to the guide section 43, the axis P2 of the center float 17 and the side floats 18 and 19 is raised to the highest position relative to the seedling planting device 5, and the seedling set depth B1 is set to the deepest position.
[0095] In the state shown in FIG. 6, the planting depth lever 42 is operated to the rearmost position relative to the guide section 43, the axis P2 of the center float 17 and the side floats 18 and 19 is lowered to the lowest position relative to the seedling planting device 5, and the seedling set depth B1 is set to the shallowest position.
[0096] As shown in FIGS. 5, 6, and 19, in the control device 70 (elevation control unit 71), the height from the ground surface G (center float 17) to a height sensor 68 (detection axis 68a) is set as a set height A1. When the height from the ground surface G (center float 17) to the height sensor 68 (detection axis 68a) is the set height A1, a detection arm 54 (detection value of the height sensor 68) is at a neutral position C1.
[0097] When the planting depth lever 42 is operated forward relative to the guide section 43 (toward a deeper seedling set depth B1), a linking rod 58 is operated forward, the support member 53 is operated upward by a first link 51 and a second link 52, and the height from the ground surface G (center float 17) to the height sensor 68 (detection axis 68a) is maintained at the set height A1.
[0098] When the planting depth lever 42 is operated rearward relative to the guide section 43 (toward a shallower seedling set depth B1), the linking rod 58 is operated rearward, the support member 53 is operated downward by the first link 51 and the second link 52, and the height from the ground surface G (center float 17) to the height sensor 68 (detection axis 68a) is maintained at the set height A1.
[0099] Control of elevation of seedling planting device: 2
As shown in FIGS. 5, 6, and 19, when the seedling planting device 5 moves up or down relative to the center float 17 that follows the ground surface G in contact therewith, the detection arm 54 (detection value of the height sensor 68) moves upward (downward) from the neutral position C1, and therefore the control valve 49 is operated by the elevation control unit 71, and the seedling planting device 5 is raised or lowered by the hydraulic cylinder 7 such that the detection arm 54 (detection value of the height sensor 68) is at the neutral position C1.
[0100] Due to the seedling planting device 5 being raised or lowered such that the detection arm 54 (detection value of the height sensor 68) is at the neutral position C1, the height from the ground surface G (center float 17) to the height sensor 68 (detection axis 68a) is maintained at the set height A1, and the depth at which seedlings are planted by the planting arms 16 is maintained at the set depth B1.
[0101] Relationship between limiter of height detector and limiting mechanism: 1
The following describes a relationship between the limiter 48 of the height detector 50 and the limiting mechanism 67 of the center float 17.
[0102] As shown in FIGS. 5 and 6, in the case where the height from the ground surface G (center float 17) to the height sensor 68 (detection axis 68a) is the set height A1, and furthermore the height detected by the detection arm 54 (detection value of the height sensor 68) is the neutral position C1 (see FIG. 19), in the limiting mechanism 67, the limiting pin 65 is located at a longitudinal central portion of the elongated hole 66a of the limiting link 66.
[0103] When the seedling planting device 5 descends relative to the center float 17 (when the center float 17 rises relative to the seedling planting device 5), the front portion of the detection arm 54 comes into contact with the front end of the limiter 48, and the height detector 50 portion of the center float 17 is limited at the upper limit position of the height detector 50.
[0104] While the height detector 50 portion of the center float 17 is limited at the upper limit position of the height detector 50, in the limiting mechanism 67, the limiting pin 65 has not reached the front end portion of the elongated hole 66a of the limiting link 66, and the limiting mechanism 67 portion of the center float 17 is still able to rise.
[0105] If the limiting mechanism 67 of the center float 17 further rises due to twisting of the center float 17, in the limiting mechanism 67, the limiting pin 65 comes into contact with the front end portion of the elongated hole 66a of the limiting link 66, and the limiting mechanism 67 portion of the center float 17 is limited at the upper limit position of the limiting mechanism 67.
[0106] When the seedling planting device 5 rises relative to the center float 17 (when the center float 17 descends relative to the seedling planting device 5), the rear portion of the detection arm 54 comes into contact with the rear end portion of the limiter 48, and the portion of the center float 17 near the height detector 50 is limited at the lower limit position of the height detector 50.
[0107] While the height detector 50 portion of the center float 17 is limited at the lower limit position of the height detector 50, in the limiting mechanism 67, the limiting pin 65 has not reached the rear end portion of the elongated hole 66a of the limiting link 66, and the limiting mechanism 67 portion of the center float 17 is still able to descend.
[0108] If the limiting mechanism 67 of the center float 17 further descends due to twisting of the center float 17, in the limiting mechanism 67, the limiting pin 65 comes into contact with the rear end portion of the elongated hole 66a of the limiting link 66, and the limiting mechanism 67 portion of the center float 17 is limited at the lower limit position of the limiting mechanism 67.
[0109] Relationship between limiter of height detector and limiting mechanism: 2
According to the above configuration, as shown in FIGS. 5 and 6, the upper limit position of the limiting mechanism 67 is set higher than the upper limit position of the limiter 48 of the height detector 50, and the lower limit position of the limiting mechanism 67 is set lower than the lower limit position of the limiter 48 of the height detector 50.
[0110] The height detector 50 is provided on one side, namely either the right side or the left side, of the portion (attachment member 59 portion) of the center float 17 (float) that is supported by the seedling planting device 5 (work device) so as to be capable of swinging up and down.
[0111] The limiting mechanism 67 is provided on the other side of the portion (attachment member 59 portion) of the center float 17 (float) that is supported by the seedling planting device 5 (work device) so as to be capable of swinging up and down.
[0112] As shown in FIG. 12, the center float 17 (float) includes the first portion 91 supported by the seedling planting device 5 (work device) so as to be capable of swinging up and down, and the second portion 92 that is connected to a front portion of the first portion 91 and has the left-right width W21 that is greater than the left-right width W11 of the first portion 91.
[0113] As shown in FIG. 4, the height detector 50 is provided in one portion, namely either the right portion or the left portion, of the second portion 92. The limiting mechanism 67 is provided in the other portion of the second portion 92.
The planting transmission case 14 is arranged at a position spaced apart in the left-right direction from the region above the limiting mechanism 67.
[0114] Overall configuration of leveler
As shown in FIGS. 1 and 2, the leveler 30 is supported by a front portion of the seedling planting device 5, and the leveler 30 is arranged rearward of the rear wheels 2.
As shown in FIGS. 2 and 16, the leveler 30 includes a transmission case 80, a support frame 81, a drive shaft 82, rotating bodies 83 and 84 for ground leveling, a support frame 85, and a cover 86.
[0115] A support case 78 is coupled to the planting transmission case 14 at the left end, and a support bracket 79 is coupled to a right end portion of the support frame 13. The transmission case 80 is supported by the support case 78 so as to be capable of swinging up and down about an 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 capable of swinging up and down about the axis P8, and extends obliquely forward and downward.
[0116] The drive shaft 82 is supported by the transmission case 80 and a front portion of the support frame 81 so as to be rotatable about an axis P9 along the left-right direction. A plurality of rotating bodies 83 are attached to a lateral central portion of the drive shaft 82 so as to be located in front of the center float 17. A plurality of rotating bodies 84 are attached to right and left portions of the drive shaft 82 so as to be located in front of the side floats 18 and 19.
[0117] The support frame 85 is shaped as a round pipe and coupled to the transmission case 80 and the support frame 81. The cover 86 is made of sheet metal and coupled to the support frame 85, and is provided rearward of the rotating bodies 83 and 84.
[0118] A transmission shaft 87 is supported by the support case 78 and an inner portion of the transmission case 80, and is coupled to the input shaft 31 of the planting transmission case 14 at the left end. Inside the transmission case 80, a transmission chain 88 is attached to a sprocket provided on the transmission shaft 87 and a sprocket of the drive shaft 82, and a torque limiter 89 is provided between the transmission chain 88 and the sprocket of the transmission shaft 87.
[0119] Motive 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 thus the drive shaft 82 and rotating bodies 83 and 84 are driven to rotate counterclockwise as shown in the figure. Due to the rotating bodies 83 and 84 being driven to rotate in the counterclockwise direction in FIG. 16, the ground surface G is leveled, and mud flung rearward from the rotating bodies 83 and 84 is blocked by the cover 86.
[0120] Configuration for elevation of leveler
As shown in FIGS. 4 and 16, a leveler elevation mechanism 105 (corresponding to a leveler position changing section) extends between the support frame 13 and the leveler 30, and is arranged at a position leftward of the link mechanism 4 (see FIG. 1) and above a left portion of the second portion 92 of the center float 17. The leveler elevation mechanism 105 includes a support frame 106, an elevation gear 107, a gear mechanism 108, an electric motor 109, and a connecting member 110. The elevation gear 107 is supported by the support frame 106 so as to be capable of swinging up and down about an axis P10 along the left-right direction. The gear mechanism 108, which includes a pinion gear 108a, and the electric motor 109, which drives the gear mechanism 108, are attached to an upper portion of the support frame 106, and a pinion gear 108a is meshed with the elevation gear 107.
[0121] The connecting member 110 is attached to the drive shaft 82 of the leveler 30 via a bearing, and an upper portion of the connecting member 110 is connected to the elevation gear 107. When the pinion gear 108a of the gear mechanism 108 is driven to rotate forward or in reverse by the electric motor 109, the elevation gear 107 is swung up or down about the axis P10, and the vertical support position of the leveler 30 in the seedling planting device 5 is changed via the connecting member 110. Note that the leveler elevation mechanism 105 (leveler position changing section) is provided within the range of the left-right width W21 of the second portion 92 of the center float 17 in a front view.
[0122] Configuration for adjustment of height of leveler
As shown in FIGS. 16 and 19, a height sensor 111 is provided to detect the angle of the elevation gear 107 relative to the support frame 106, and the detection value of the height sensor 111 is input to the control device 70. The height of the leveler 30 relative to the seedling planting device 5 is detected based on the angle of the elevation gear 107 relative to the support frame 106 detected by the height sensor 111.
[0123] A planting depth sensor 113 is provided to detect the operation position of the planting depth lever 42, the detection value of the planting depth sensor 113 is input to the control device 70, and the seedling set depth B1 (see FIGS. 5 and 6) is detected based on the operation position of the planting depth lever 42.
[0124] A manually operable height adjustment switch 112 is provided in the vicinity of the steering wheel 9 (see FIG. 1), and an operation signal of the height adjustment switch 112 is input to the control device 70. The height adjustment switch 112 enables setting and changing a leveling set height A2 (leveling depth), which is the height from the ground surface G to the leveler 30 (drive shaft 82).
[0125] A leveler elevation control unit 72 is provided as software 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 leveler elevation control unit 72 operates the electric motor 109 and changes the vertical support position of the leveler 30 in the seedling planting device 5, as described below.
[0126] The seedling set depth B1 (see FIGS. 5 and 6) is detected based on the detection value of the planting depth sensor 113, and the height of the leveler 30 relative to the seedling planting device 5 is detected by the height sensor 111, and thus the height from the ground surface G to the leveler 30 (drive shaft 82) is detected.
[0127] The electric motor 109 is operated to change the vertical support position of the leveler 30 in the seedling planting device 5 such that the height from the ground surface G to the leveler 30 (drive shaft 82) becomes the leveling set height A2 (leveling depth) that was set (changed) by the height adjustment switch 112.
[0128] When the planting depth lever 42 is operated and the seedling set depth B1 (see FIGS. 5 and 6) is changed, the height from the ground surface G to the leveler 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.
[0129] Similarly to the configuration described above, the electric motor 109 is operated to change the vertical support position of the leveler 30 in the seedling planting device 5 such that the height from the ground surface G to the leveler 30 (drive shaft 82) becomes the leveling set height A2 (leveling depth) that was set (changed) by the height adjustment switch 112.
[0130] Accordingly, even if the planting depth lever 42 is operated and the seedling set depth B1 (see FIGS. 5 and 6) is changed, the height from the ground surface G to the leveler 30 (drive shaft 82) is maintained at the leveling set height A2 (leveling depth) that was set (changed) by the height adjustment switch 112.
[0131] First variation of invention
The recesses 97 and 98 may be omitted from the upper face portion 92a of the second portion 92 of the center float 17.
In the lower face portions 92b and 92c and the connection portion 92d of the second portion 92 of the center float 17, it is not required that the left-right width of the recess 99 increases toward the front, and, similarly to the recess 100, the left-right width of the front portion of the recess 99 may be the same as the left-right width of the rear portion of the same.
[0132] Second variation of invention
The center float 17 may have a configuration in which the widths W22 and W23 shown in FIG. 12 are set slightly smaller than the width W11, and the width W21 is greater than two times the width W11 and less than three times the width W11.
The length L2 may be longer than the length L1.
[0133] Third variation of invention
The configuration of the center float 17 shown in FIGS. 12 to 15 may be adopted for the side floats 18 and 19. In this case, the configurations described in the above sections “First variation of invention” and “Second variation of invention” may be adopted for the side floats 18 and 19.
[0134] Fourth variation of invention
In the center float 17, if the width W21 shown in FIG. 12 is greater than two times the width W11 and less than three times the width W11 as described in the above section “Second variation of invention”, the planting depth lever 42 (float position changing section) may be provided outside the range of the left-right width W21 of the second portion 92 in a front view.
[0135] Similarly, the leveler elevation mechanism 105 (leveler 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 in a front view.
The height detector 50 may be provided outside the range of the left-right width W21 of the second portion 92 of the center float 17 in a front view.
[0136] Fifth variation of invention
In the support arms 41a, 41b, and 41c of the fulcrum member 41 shown in FIG. 3, the distance W1 and the distance W2 may be the same value, and the distance W3 may be smaller than the distances W1 and W2.
[0137] The distances W1, W2, and W3 may be different from each other. In this case, the values of the distances W1, W2, and W3 may be set such that the following relational expressions 1 to 4 are satisfied.
(1) distance W1 > distance W2 > distance W3
(2) distance W1 < distance W2 < distance W3
(3) distance W1 > distance W2 = distance W3
(4) distance W1 < distance W2 = distance W3
[0138] Sixth variation of invention
Regarding the support arms 41a and 41b of the fulcrum member 41, similarly to the support arms 41c of the fulcrum member 41 shown in FIGS. 10 and 11, rear portions of the support arms 41a (41b) of the fulcrum member 41 may be coupled to each other by the first member 39, and portions of the support arms 41a (41b) on the fulcrum member 41 side of the first member 39 may be coupled to each other by the second member 40.
The second member 40 may connect lateral face portions of the support arms 41a (41b) of the fulcrum member 41.
[0139] Seventh variation of invention
Regarding the support arms 41b and 41c of the fulcrum member 41, in the case where lateral face portions of the support arms 41b (41c) of the fulcrum member 41 are coupled to each other by the second member 40, the open portion of the second member 40 may face rearward as shown in FIG. 20.
According to the above configuration, the open portion of the second member 40 faces rearward.
[0140] Regarding the support arms 41a of the fulcrum member 41, in the case where lateral face portions of the support arms 41a of the fulcrum member 41 are coupled to each other by the second member 40, the open portion of the second member 40 may face rearward as shown in FIG. 20.
[0141] Regarding the support arms 41a, 41b, and 41c of the fulcrum member 41, in the case where lateral face portions of the support arms 41a (41b, 41c) of the fulcrum member 41 are coupled to each other by the second member 40, the open portion of the second member 40 may face downward.
[0142] Eighth variation of invention
In the limiter 48 of the height detector 50 shown in FIGS. 5 and 6, the upper limit position may be provided and the lower limit position may be omitted, or the lower limit position may be provided and the upper limit position may be omitted. In the limiting mechanism 67, the upper limit position may be provided and the lower limit position may be omitted, or the lower limit position may be provided and the upper limit position may be omitted.
[0143] The above-described configurations may be combined as described in (1) to (6) below.
(1) In the limiter 48 of the height detector 50, the upper limit position is provided, and the lower limit position is omitted. In the limiting mechanism 67, the upper limit position is provided, and the lower limit position is omitted.
(2) In the limiter 48 of the height detector 50, the upper limit position is omitted, and the lower limit position is provided. In the limiting mechanism 67, the upper limit position is omitted, and the lower limit position is provided.
(3) In the limiter 48 of the height detector 50, the upper limit position is provided, and the lower limit position is omitted. In the limiting mechanism 67, the upper limit position is omitted, and the lower limit position is provided.
(4) In the limiter 48 of the height detector 50, the upper limit position is omitted, and the lower limit position is provided. In the limiting mechanism 67, the upper limit position is provided, and the lower limit position is omitted.
(5) In the limiter 48 of the height detector 50, either the upper limit position or the lower limit position is provided. In the limiting mechanism 67, both the upper limit position and the lower limit position are provided.
(6) In the limiter 48 of the height detector 50, both the upper limit position and the lower limit position are provided. In the limiting mechanism 67, either the upper limit position or the lower limit position is provided.
[0144] Ninth variation of invention
In the height detector 50 and the limiting mechanism 67, the height detector 50 may be provided on a left portion of the second portion 92 of the center float 17, and the limiting mechanism 67 may be provided on a right portion of the second portion 92 of the center float 17.
[0145] Tenth variation of invention
The seedling planting device 5 may have a configuration in which the rotation case 15 is omitted, one planting arm 16 is rotatably supported by a right portion of the planting transmission case 14, and one planting arm 16 is rotatably supported by a left portion of the planting transmission case 14.
Instead of the seedling planting device 5, a seeding device (not shown) for supplying rice seed to the ground surface G may be provided as the work device.

Industrial Applicability
[0146] The present invention is applicable to a paddy field work machine in which a work device, such as a seedling planting device or a seeding device, is elevatably supported by a rear portion of a body supported by travel wheels.

Description of Reference Signs
[0147] 1 Front wheel (wheel)
2 Rear wheel (wheel)
3 Body
5 Seedling planting device (work device)
17 Center float (float)
30 Leveler
42 Planting depth lever (float position changing section)
50 Height detector
71 Elevation control unit
90 Connection portion (portion)
91 First portion
91b Lower face portion
92 Second portion
92a Upper face portion
92b Lower face portion
92c Lower face portion
97 Recess (upper recess)
99 Recess (lower recess)
101 Attachment portion
105 Leveler position changing section
A1 Set height
G Ground surface
L1 Length
L2 Length
W11 Width
W21 Width
W22 Width
W23 Width
?1 Forward rising angle
?2 Forward rising angle
, Claims:CLAIMS

1. A paddy field work machine comprising:
a body supported by travel wheels;
a work device elevatably supported by a rear section of the body; and
a float supported by a lower section of the work device in such a manner as to be swingable up and down, and configured to follow a ground surface in contact therewith,
wherein the float includes:
a first portion supported by a lower section of the work device; and
a second portion connected to a front portion of the first portion and extending obliquely forward and upward from the front portion of the first portion in a side view, and
the second portion has a lower face portion angled relative to a lower face portion of the first portion by a forward rising angle greater than a forward rising angle of an upper face portion of the second portion relative to the lower face portion of the first portion in a side view.

2. The paddy field work machine according to claim 1,
wherein the second portion includes:
a portion corresponding to a mating portion of a pair of molds in blow molding; and
an intermediate portion located between the upper face portion of the second portion and the lower face portion of the second portion, and
the portion of the second portion corresponding to the mating portion is located closer to the lower face portion of the second portion than the intermediate portion is, in a side view.

3. The paddy field work machine according to claim 1 or 2,
wherein the upper face portion of the second portion extends obliquely forward and upward from a front portion of an upper face portion of the first portion in a side view,
the lower face portion of the second portion includes:
a first lower face portion extending forward from the lower face portion of the first portion in parallel with the lower face portion of the first portion in a side view; and
a second lower face portion extending obliquely forward and upward from a front portion of the first lower face portion in a side view, and
the second lower face portion of the second portion is angled relative to the lower face portion of the first portion by a forward rising angle greater than the forward rising angle of the upper face portion of the second portion relative to the lower face portion of the first portion in a side view.

4. The paddy field work machine according to anyone of claims 1-3,
wherein the upper face portion of the second portion includes an upper recess recessed from the upper face portion of the second portion toward the lower face portion of the second portion, and
the upper recess extends in a front-rear direction and has a depth, from the upper face portion of the second portion, that decreases as the upper recess extends rearward.

5. The paddy field work machine according to anyone of claims 1-4,
wherein the lower face portion of the second portion includes a lower recess recessed from the lower face portion of the second portion toward the upper face portion of the second portion, and
the lower recess extends in a front-rear direction and has a left-right width that increases as the lower recess extends forward.

6. The paddy field work machine according to anyone claims 1-5,
wherein the second portion has a left-right width greater than two times a left-right width of the first portion.

7. The paddy field work machine according to claim 6,
wherein the first portion has a right end portion and a left end portion,
the second portion has a right end portion and a left end portion,
the right end portion of the first portion is separated from the right end portion of the second portion by a left-right distance greater than the left-right width of the first portion, and
the left end portion of the first portion is separated from the left end portion of the second portion by a left-right distance greater than the left-right width of the first portion.

8. The paddy field work machine according to anyone of claims 1-7,
wherein the second portion has a front-rear length shorter than a front-rear length of the first portion.

9. The paddy field work machine according to anyone of claims 1-8, further comprising:
a float position changing section configured to change, in an up-down direction, a support position at which the float is supported by the lower section of the work device,
wherein the float position changing section is within a range of the left-right width of the second portion in a front view.

10. The paddy field work machine according to anyone of claims 1-9, further comprising:
a leveler supported by the work device, located in front of the float, and configured to level the ground surface; and
a leveler position changing section configured to change, in an up-down direction, a support position at which the leveler is supported by the work device,
wherein the leveler position changing section is within a range of the left-right width of the second portion in a front view.

11. The paddy field work machine according to anyone of claims 1-10, further comprising:
a height detector configured to detect a height of the work device from the float; and
an elevation control unit configured to raise and lower the work device relative to the body based on the height detected by the height detector, in such a manner that the height of the work device is maintained at a predetermined set height from the ground surface,
wherein the second portion includes, in a front end portion, an attachment portion extending to a position below the upper face portion of the second portion in a side view, and
the height detector is attached to the attachment portion.