Agricultural work vehicle

Abstract

To provide an agricultural work vehicle that allows an operator to, without obstruction, move laterally or perform on-the-spot replenishment of seedlings, a fertilizer and the like at the rear side of a driver's seat arranged substantially at a rear-center portion of a traveling body, when replenishing the seedlings, fertilizer and the like to a working implement provided at or behind the rear of the traveling body.SOLUTION: An upper part of a seat frame has: an attachment portion to pivotally support a front portion of a driver's seat; and a support plate to support a rear portion of the driver's seat, the support plate being equipped with a cushion rubber and a spring for floating. The driver's seat is thereby arranged to be capable of tilting toward a steering handle provided in front of the driver's seat. Meanwhile, an operating lever suspended downward from a near-central portion of the driver's seat has its distal end brought into contact with a detection body of a rotation-detection type sitting sensor provided below the support plate, thereby detecting the operator's sitting on the driver's seat.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to agricultural work vehicles such as riding rice transplanters or riding tillers for sowing seeds, fertilizing, spraying chemicals, etc. in fields. [Background technology]

[0002] A riding rice transplanter, which has traditionally been an agricultural work vehicle, has a planting device that can be raised and lowered at the rear of a traveling body with left and right front and rear wheels, and this planting device is used to plant rice seedlings in paddy fields.In addition, riding rice transplanters are equipped with a paste fertilizer applicator or granular fertilizer applicator at the rear of the traveling body to reduce the amount of fertilizer applied and the labor required in rice cultivation systems, so that these fertilizer applicators can be used to plant seedlings and apply fertilizer at the same time.

[0003] Furthermore, in response to the needs of large-scale farmers and agricultural corporations, riding rice transplanters aim to increase the number of rows of seedlings that can be planted at once, such as 6, 8, or 10 rows, and to shorten the work time by increasing the planting speed. Also, in such seedling planting work, the supply of seedlings to the planting device and the supply of fertilizer to the fertilizer applicator are done manually, so it is necessary to shorten the time lost in these supplying operations and emphasize continuous planting work to improve work efficiency and work to reduce production costs.

[0004] Therefore, in order to enable the rapid supply of seedlings and fertilizer in multi-row rice transplanters, for example, the riding rice transplanter with eight-row planting specifications described in Patent Document 1 has a seedling planting device connected to the rear of the traveling body so that it can be raised and lowered, and a fertilizer applicator equipped with a fertilizer hopper for storing granular fertilizer is provided at the rear of the traveling body.The rear of the step (floor) provided at the feet of the driver's seat, which is provided near the rear of the traveling body, is bent and extended one step higher on the sides of the driver's seat to form a series of auxiliary steps that wrap around from the left and right sides of the driver's seat to the rear, and a climbing step of the same height as the auxiliary step is extended from the rear of the extended step.

[0005] In addition, the driver's seat is configured so that its sliding position can be freely adjusted back and forth by operating a lock release lever, and by moving the driver's seat far forward, the space between the driver's seat and the fertilizer hopper can be widened, allowing the operator to move freely left and right and stand on the auxiliary steps or climbing steps to easily supply seedlings taken from the spare seedling tray to the seedling tray of the seedling planting device from a high position.

[0006] Similarly, the riding rice transplanter described in Patent Document 2 is provided with a rear step that rises upward from the rear end of the driver's step located in front of the driver's seat and extends rearward, and is configured so that this rear step can be used to supply seedlings to a seedling planting device located at the rear.In this riding rice transplanter, an upper connector is erected and connected across the upper ends of a pair of left and right vertical frames that stand upright from the machine frame, and the front lower part of the driver's seat is pivotally connected to this upper connector, so that the rear side of the driver's seat can be lifted upward and switched to a maintenance position.

[0007] Meanwhile, the automation and efficiency of agricultural work has been advocated to resolve the labor shortage caused by the decline in agricultural workers and the aging of the population.In addition, with ride-on rice transplanters, emphasis is placed on reducing untouched and overlapping work areas and improving work efficiency by driving the machine body as straight as possible and at regular work intervals, and development is underway on automatic driving of ride-on rice transplanters, including a straight-line automatic steering system using the Global Navigation Satellite System (GNSS) and the ability to turn the machine body on headland areas.

[0008] In such a straight-line automatic steering system, if the operator selects automatic steering at the start of one planting cycle, the operator takes his or her hands off the steering wheel and the automatic steering operation begins, and the automatic steering operation continues even if the operator subsequently stands up and leaves the driver's seat for some reason. However, since it is dangerous for the vehicle to continue operating while the operator is away from the seat, it is known that when a seat sensor detects that the operator has left the driver's seat, an alarm is sounded or the engine is stopped by a control device to prevent the riding rice transplanter from further traveling under automatic steering (see Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-278765 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-203360 [Patent Document 3] Patent Publication No. 2021-108614 [Patent Document 4] Japanese Patent Application Publication No. 2023-154145 Summary of the Invention [Problem to be solved by the invention]

[0010] As mentioned above, in agricultural work vehicles such as riding rice transplanters, the driver's seat is located in the center near the rear of the running body, and work steps (steps to climb up, auxiliary steps) are provided on both the left and right sides of the driver's seat to the rear.The worker stands up from the floor (steps provided at the feet of the driver's seat) provided in front of the work steps and supplies seedlings, fertilizer, etc. to the work equipment (seedling planting equipment, fertilizer application equipment) provided at the rear or back of the running body.

[0011] When supplying seedlings, fertilizer, etc. to the work equipment installed at the rear or rear of the traveling machine body, if work steps are provided from both the left and right sides of the driver's seat to the rear, the worker can stand on the work steps from the floor and quickly supply seedlings, fertilizer, etc. to the work equipment installed at the rear or rear of the traveling machine body from a high position. However, if the length of the work steps (scaffolding) is short in this case, there will be insufficient space for the feet, forcing the worker into an unstable position.

[0012] Therefore, if the length of the work steps is lengthened so that the worker can perform the supplying work in a comfortable and stable position, in this case the length of the running body increases (the vehicle becomes larger), and a compact work vehicle with little headland that can be made to turn sharply cannot be obtained. This problem becomes more pronounced when a fertilizer applicator is provided above the rear of the work steps, and the work steps behind the driver's seat inevitably have an insufficient length because the space in front of the driver's seat is occupied by the driver's seat, which restricts the worker's left and right movement and makes it difficult to supply seedlings, fertilizer, etc. on the spot.

[0013] Therefore, in the riding rice transplanter described in Patent Document 1, the operator operates a lock release lever to slide the driver's seat forward significantly, widening the gap between the driver's seat and the fertilizer hopper, allowing the operator to move freely left and right and easily remove spare seedlings from the spare seedling tray and then stand on the auxiliary steps or climbing-up steps to easily supply seedlings to the seedling tray of the seedling planting device from a high position.

[0014] However, even if the driver's seat is adjusted to slide forward in this way, the amount of forward movement of the seat slide device is limited by the mechanical strength, etc., so it is not possible to achieve a large forward movement distance. For example, it is difficult to say that the distance between the driver's seat and the fertilizer hopper can be widened by simply moving the backrest (seat back) forward about one-third of the front-to-rear length of the driver's seat. Furthermore, when resuming seedling planting work after seedling supplying work, the operator must adjust the front-to-rear position of the driver's seat to his or her physique by operating the lock release lever, which is inconvenient and results in wasted time.

[0015] On the other hand, Patent Document 2 describes a technical matter in which the driver's seat, which is pivotally connected to an upper connector on the body frame of a riding rice transplanter, can be tilted down by lifting the rear side of the driver's seat upward, thereby greatly opening up the seat space that had been occupied until then.If this technical means for moving the driver's seat forward is applied to the driver's seat described in the above-mentioned Patent Document 1, it should be possible to create a large gap between the driver's seat and the fertilizer hopper by tilting the driver's seat forward without having to adjust the driver's seat by sliding it forward a large distance, and it should be possible to configure the device so that seedlings can be easily replenished onto the seedling tray of the seedling planting device.

[0016] However, with this configuration, although the driver's seat itself can be tilted forward to leave the vehicle, the rails that make up the seat slide device installed below the driver's seat, the lock release device, and the cushion rubber that supports the rear of the driver's seat remain on top of the seat frame of the traveling vehicle, so workers must move left and right while straddling these parts, as they cannot step on these parts and injure their feet or damage the rails, etc. Furthermore, since these cannot be used as footholds for workers, the problem remains that it is not possible to supply seedlings, fertilizer, etc. on the spot.

[0017] Meanwhile, Patent Document 3 discloses that when a work vehicle is autonomously traveling based on its own position calculated using GNSS or the like, an occupancy sensor is provided in the driver's seat to cause an alarm device to issue a warning if the driver is not seated in the driver's seat. Furthermore, it describes that if this occupancy sensor is a pressure sensor provided in the driver's seat, wiring for a power supply, signals, etc. is connected to this pressure sensor, and such wiring may be damaged when the driver's seat rotates, so that measures such as arranging the wiring of the seat sensor along the rotation axis of the driver's seat are required to prevent such wiring from being damaged.

[0018] However, in this case, if a pressure sensor is used as the seat occupancy sensor, the seat occupancy sensor will generally be expensive because it uses a strain gauge or the like to detect seat occupancy, and it will be necessary to incorporate the seat occupancy sensor into the driver's seat and take measures for its wiring. Therefore, as described in Patent Document 4, it is possible to use a rotation detection type sensor as the seat occupancy sensor, which is relatively inexpensive, widely used in agricultural machinery, and is therefore reliable.

[0019] However, if a rotation detection sensor is used as the seat occupancy sensor in this way, and the seat occupancy sensor is configured to detect the driver leaving or sitting in the seat by detecting the seat spring that applies a force pushing the seat in the direction of moving it away from the seat bracket, the seat support part that comes into contact with the lower part of the seat to support the seat when the driver sits down and the seat spring is compressed, and the first position where the seat is pushed up by the seat spring and the second position where the seat support part supports the lower part of the seat, then when the seat is tilted forward, the seat spring and seat support part along with the seat sensor will remain on the seat bracket, which again poses the problem that the seat bracket cannot be used as a foothold for workers.

[0020] Therefore, in consideration of the above-mentioned problems, the present invention aims to provide an agricultural work vehicle in which a driver's seat is provided at the top of a seat frame located in the center near the rear of the running body, and work steps are provided on both the left and right sides of the driver's seat to the rear, so that when a worker stands up from a floor located in front of the work steps and supplies seedlings, fertilizer, etc. to work equipment located at the rear or rear of the running body, he or she can move left and right behind the driver's seat without any problems and can perform on-site supply work of seedlings, fertilizer, etc. [Means for solving the problem]

[0021] In order to solve the above problems, the agricultural work vehicle of the present invention has a driver's seat located on top of a seat frame mounted in the center near the rear of the running body, and work steps are provided on both the left and right sides of the driver's seat to the rear, and an operator stands up from a floor mounted in front of the work steps to supply seedlings, fertilizer, etc. to work equipment mounted at the rear or rear of the running body.In this agricultural work vehicle, an attachment part that pivots the front of the driver's seat and a support plate that supports the rear of the driver's seat and is equipped with cushion rubber and a levitation spring are provided on the top of the seat frame, and the driver's seat is arranged to be able to be freely tilted towards the steering handle mounted in front of it, and the tip of an operating rod that hangs down from near the center of the driver's seat is abutted against the detecting body of a rotation detection type seating sensor mounted below the support plate, thereby detecting the operator sitting in the driver's seat.

[0022] In addition, the agricultural work vehicle of the present invention is configured so that a seat slide device is attached to the underside of the driver's seat, allowing the worker to adjust the driver's seat forward and backward while remaining seated, and the driver's seat is configured so that it can be freely tilted down, along with the seat slide device, towards the steering handle located in front of it.

[0023] Furthermore, in the agricultural work vehicle of the present invention, the driver's seat can be freely adjusted in its longitudinal mounting position relative to a mounting portion provided on the upper part of the seat frame, and the length of the seat occupancy sensor's detector is set long so that the tip of the operating rod abuts against the seat occupancy sensor's detector regardless of the adjustment of the driver's seat's longitudinal mounting position. [Effects of the Invention]

[0024] According to the agricultural work vehicle of the present invention, the driver's seat is located on top of a seat frame located in the center near the rear of the running body, and work steps are located on both the left and right sides of the driver's seat to the rear. In this agricultural work vehicle, an operator stands up from a floor located in front of the work steps and supplies seedlings, fertilizer, etc. to work equipment located at the rear or rear of the running body. On the top of the seat frame, there is provided an attachment portion that pivots the front of the driver's seat, and a support plate that supports the rear of the driver's seat and is equipped with cushion rubber and a levitation spring. The driver's seat is arranged so that it can be freely folded down toward the steering handle located in front of it, and the tip of the operating rod that hangs down from near the center of the driver's seat is abutted against the detecting body of a rotation detection type seating sensor located below the support plate, thereby detecting the operator sitting in the driver's seat.

[0025] Therefore, before starting work or when the worker stops working to replenish the work equipment with seedlings, fertilizer, etc., the worker can sit in the driver's seat and drive the work equipment while tilting it down toward the steering handle located in front of it, thereby freeing up the space that had previously been occupied by the driver's seat, cushion rubber, or levitation spring.As a result, the worker can move left and right through the open space above the work step, without having to make unnecessary movements such as going around the floor when carrying the seedlings, fertilizer, etc. to be replenished, and can then reach the desired location and accurately replenish the seedlings, fertilizer, etc. to the work equipment behind.

[0026] Therefore, the length of the work steps extending from the left and right sides of the driver's seat to the rear can be minimized, resulting in a compact work vehicle.In addition, the rotary detection type seating sensor that detects when the worker is sitting in the driver's seat, along with the detection body attached to its rotating shaft, is located below the support plate that supports the rear of the driver's seat and is located at the top of the seat frame, so it does not get in the way.This support plate can be used as a foothold when supplying seedlings, fertilizer, etc., and the worker can stand on the work steps or the top of this support plate and supply seedlings, fertilizer, etc. to the work equipment located behind it in a stable position.

[0027] As mentioned above, the seat occupancy sensor is a rotation detection type sensor that is inexpensive, reliable, and has stable performance, and since this seat occupancy sensor is installed below the support plate, it will not be damaged or injured by the foot of an operator placed on the support plate. Furthermore, the seat occupancy sensor detects the operator's seat by abutting the tip of the operating rod hanging down from the driver's seat against the detector of the seat occupancy sensor, so the wiring to the control device that issues an alarm for departing from the seat, etc., can be easily routed without requiring measures such as routing from the driver's seat along the rotation axis of the driver's seat.

[0028] Furthermore, according to the agricultural work vehicle of the present invention, a seat slide device is attached to the underside of the driver's seat, allowing the worker to adjust the driver's seat fore and aft while remaining seated, and the driver's seat is arranged so that it can be freely folded down along with the seat slide device towards the steering handle provided in front of it, so that when replenishing seedlings, fertilizer, etc., the seat slide device along with the driver's seat can be moved out of the supply passage so as not to get in the way.

[0029] Furthermore, even if the driver's seat is tilted forward with the seat slide device, the position of the driver's seat that has been adjusted for forward and backward movement when the worker travels for work, etc., is maintained. Therefore, when replenishing seedlings, fertilizer, etc. and resuming work travel, the driver's seat can be returned to its original seating position with the seat slide device, without the need to adjust the forward and backward movement again. This reduces the overall time lost during replenishing work and contributes to reducing production costs by improving work efficiency.

[0030] According to the agricultural work vehicle of the present invention, the driver's seat is attached to a mounting portion provided on the upper part of the seat frame in a freely adjustable position in the fore-and-aft direction, and the length of the detector of the seat occupancy sensor is set long so that the tip of the operating rod properly abuts against the detector of the seat occupancy sensor regardless of the adjustment of the fore-and-aft attachment position of the driver's seat. Therefore, even if the fore-and-aft position of the driver's seat is adjusted to suit the physique or preferences of the worker by adjusting the fore-and-aft attachment position of the driver's seat without a seat slide device, the long detector of the seat occupancy sensor can reliably detect the worker's seating, allowing the vehicle to be driven safely for work even when an automatic steering device is used for automatic straight-line control, etc. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a perspective view of a riding rice transplanter to which the present invention is applied. [Figure 2] FIG. 1 is a plan view of a riding rice transplanter. [Figure 3] FIG. 4 is a perspective view showing the attachment of a driver's seat to a chassis frame. [Figure 4] FIG. 2 is a perspective view showing the installation of a seat slide device to a driver's seat. [Figure 5] FIG. 2 is a front view showing a state in which a driver's seat equipped with a seat slide device is attached to a seat frame. [Figure 6] FIG. 10 is a side cross-sectional view showing a state in which the driver's seat has been moved to the rearmost position. [Figure 7] FIG. 10 is a side cross-sectional view showing a state in which the driver's seat has been moved forward to the maximum extent. [Figure 8]FIG. 1 is a perspective view of a riding rice transplanter showing a state in which the driver's seat is reclined. [Figure 9] FIG. 1 is a plan view of a riding rice transplanter showing the driver's seat in a reclined position. [Figure 10] FIG. 10 is a side cross-sectional view showing the driver's seat in a state where it has been moved rearward to the maximum extent and then tilted down. [Figure 11] FIG. 10 is a side cross-sectional view showing the driver's seat in a state where it has been moved forward to the maximum extent and then tilted down. [Figure 12] This is an oblique view of a riding rice transplanter with paste fertilizer applicator specifications. [Figure 13] This is an oblique view of a riding rice transplanter with paste fertilizer applicator specifications, showing the driver's seat in the reclined position. [Figure 14] FIG. 10 is a side cross-sectional view showing a state in which a driver's seat not provided with a seat slide device is attached to a seat frame. DETAILED DESCRIPTION OF THE INVENTION

[0032] An embodiment of the present invention will be described with reference to the drawings. As shown in Figures 1 and 2, a riding rice transplanter 1, which is an agricultural work vehicle, has a planting device 6 as a working device connected to the rear of a traveling body 4, which has left and right front wheels 2 and rear wheels 3, via a link mechanism 5 so that the planting device 6 can be freely rolled. The planting device 6 is then raised and lowered between a lowered working position and a raised non-working position by a hydraulic cylinder 7 attached between the rear of the traveling body 4 and the rear of the link mechanism 5.

[0033] As shown in Figure 3, the running body 4 is equipped with a chassis frame 10 constructed by fastening a plurality of cross members 9 formed from channel steel or the like to left and right side members 8 formed from square steel pipes or the like, and a diesel engine (engine) 12 is mounted on an engine frame 11 fixed to the front of the chassis frame 10. A transmission frame 13 for mounting a transmission case and a front axle case is fixed to the rear of the engine frame 11, and an axle frame 14 for mounting a rear axle case is fixed to the rear of the chassis frame 10.

[0034] A torque generator constituting a power steering device is attached to the top surface of a transmission case provided behind the diesel engine 12, and a steering shaft 15 extending upward and a steering column 16 containing the steering shaft 15 are provided upright on the torque generator. A steering handle 17 for steering the front wheels 2 is provided on the upper end of the steering shaft 15 (see FIG. 6, etc.).

[0035] Meanwhile, a bracket is fixed to the middle of the steering column 16, and the main speed change lever, sub speed change lever, and engine control lever are rotatably attached to the left and right sides of this bracket, with a panel cover 18 covering the base sides of these and equipped with a quick-up lever and monitor panel for raising and lowering the planting device 6. Also, below the panel cover 18, a rear cover 19 is provided on which the engine starter switch and other components are attached, and in front of these panel covers 18 and rear cover 19, a hood 20 is provided to cover the diesel engine 12, air cleaner, etc.

[0036] Furthermore, a step frame 22 formed from a framework of steel pipes, channel steel, etc. is fixed or attached to the aforementioned chassis frame 10 and a seat frame 21 (described later) fixed to the chassis frame 10, and a synthetic resin panel is attached to this step frame 22, with the upper surface of the panel constituting the floor of the operating section and a work step. More specifically, on both the left and right sides of a center floor 24 where an operator sitting in a driver's seat 23 provided above the seat frame 21 grips a steering handle 17 provided in front to operate the riding rice transplanter 1, side floors 25 and a wide floor (extended floor) 26 are provided without any step from the center floor 24.

[0037] A brake pedal 27 for braking the traveling body 4 to a stop is provided near the boundary between the center floor 24 and the right side floor 25 near the front, and auxiliary steps 28 are provided below the left and right wide floors 26 to make it easier for workers to get on and off the floors 24 to 26. Furthermore, left and right front side steps 29 are provided in front of the left and right side floors 25, continuing seamlessly with the side floors 25, and these left and right front side steps 29 serve as a path for workers to get on and off from the edge of the ridges to the floors 24 to 26 when planting seedlings in a rice paddy, and also as a path for transporting seedlings and fertilizer.

[0038] The work steps, which are bent in a stepped manner from the rear ends of the aforementioned floors 24 to 26 and have flat upper surfaces as footholds, are made up of left and right rear side steps 30 that continue from the left and right side floors 25, left and right wide steps 31 that continue without any steps to the left and right rear side steps 30, and a rear center step 32 that is located behind the driver's seat 23 and is sandwiched between the rear parts of the left and right rear side steps 30.

[0039] Of the floors 24 to 26, the center floor 24 located in the center is bent in a stepped manner from the rear end and has a concave recess 33a in the center of its upper surface, which serves as a cover 33 that covers the left and right peripheral portions of the opening formed on the front and upper side of the seat frame 21.Furthermore, on the left and right sides of the recess 33a of this cover 33, recesses 33b that serve as drink holders and recesses 33c that serve as storage areas for small items are integrally molded, and the cover is made slightly higher than the left and right rear side steps 30 and rear center step 32, so it is not particularly desirable to use the upper surface of this area as a work step (see Figures 1 and 6, etc.).

[0040] Additionally, a fertilizer frame 34, on which a fertilizer applicator (described later) is mounted, is provided behind the aforementioned rear side step 30, extending rearward from the aforementioned step frame 22, and flat left and right covers 35 are attached to the top of this fertilizer frame 34 to prevent mud scattered from the rice field below as the vehicle travels from adhering to the fertilizer applicator located above. The rear center step 32, located behind the driver's seat 23, also serves as a cover at its rear, blocking the area below the fertilizer applicator. Therefore, although the top surfaces of these covers 35 and the rear of the rear center step 32 are flat, they cannot be used as work steps because the fertilizer applicator is located above them.

[0041] The basic configuration of the traveling machine body 4 has been explained above, but to briefly explain the power transmission system of the riding rice transplanter 1, the engine 12 drives the HST (hydrostatic continuously variable transmission: main transmission) attached to the transmission case via a transmission belt. Furthermore, power transmitted from the HST into the transmission case passes through an auxiliary transmission composed of a gear transmission provided in the transmission case and a differential gear device for the front wheels 2, and then drives the left and right front wheels 2 via transmission shafts provided in the left and right front axle cases and kingpin case. Furthermore, the rear wheels 3 are driven from the auxiliary transmission via left and right wet disc-type side clutches provided in the rear axle case.

[0042] Furthermore, a disc brake is provided on the transmission shaft that transmits power from the sub-transmission to the left and right side clutches, and when the brake pedal 27 mentioned above is depressed, the main transmission lever returns to the neutral position, the HST goes into neutral, and the disc brake is activated to apply four-wheel brakes to the front wheels 2 and rear wheels 3. Furthermore, when turning the steering wheel 17 on the headland, if the steering wheel 17 is turned more than a predetermined amount, the side clutch on the turning side is disengaged, and the rear wheel 3 on that side goes into a free-spinning state.

[0043] Next, a brief explanation of the planting device 6, which is mounted on the rear of the traveling body 4 and can be raised and lowered, will be given. This planting device 6 has a planting frame that is connected to the rear of the traveling body 4 in a rolling manner and has eight rows of planting rows. The planting frame is also equipped with a seedling carrier 36 that is tilted high in the front and low in the rear and carries multiple mat seedlings, a rotary planting mechanism 37 that uses planting claws to scrape the seedlings one by one from the bottom of the seedling carrier 36 and plant them on the rice field surface, and a float 38 that levels the planting area by leveling the tracks left by the travel and turning movements.

[0044] The power that enters the drive case of the planting device 6 via the planting clutch and inter-row transmission provided in the transmission case, as well as the PTO shaft, rotates the screw shaft, causing the seedling carrier 36 to slide back and forth left and right. The power that enters the drive case is also transmitted to the planter case that makes up the rotary planting mechanism 37, driving it to rotate. Planting claws attached to planter arms attached to the rotary case pick up seedlings one by one from the bottom of the seedling carrier 36, and then push the picked seedlings out with forks to plant them in the rice paddy field.

[0045] The left and right markers that mark the rice field surface to indicate the next work run are rotatably attached to the tips of support rods that rotatably support the planting frame of the planting device 6 at their bases, and a marker drive motor operates the support rods, allowing the markers to be switched between an active position where they touch the rice field surface to mark it, and a non-active position where they are retracted above the planting device 6. A center pole 39 is also attached to the front of the chassis frame 10 so that it can rotate back and forth, and trace markers are attached to the left and right of the chassis frame 10.

[0046] The riding rice transplanter 1 is also provided with a pair of sliding spare seedling trays 41 on the left and right that allow seedling trays containing mat seedlings to be loaded onto the seedling carrier 36 of the planting device 6 by placing seedling boxes containing mat seedlings on rollers 40 that rotatably support the trays and sliding them from the front of the traveling body 4 to above the wide step 31. The spare seedling trays 41 are foldable and mounted on the top of a frame 42 that extends beyond the front side steps 29 provided on the left and right sides of the front of the traveling body 4 and is erected outward.

[0047] Therefore, when supplying seedlings to the planting device 6, the front and rear seedling trays 41a and 41c are each spread out relative to the central seedling tray 41b, and an assistant worker or the like places a seedling box containing mat seedlings on the rollers 40 of the front seedling tray 41a from a farm road or bank, etc., and the seedling box can be easily moved up to the top of the wide step 31 in the downward sloping transport direction.This significantly reduces the effort and time required, for example, compared to a worker standing up on the front side step 29 from a farm road or bank, etc., and carrying the seedling box to the rear work step (rear side step 30).

[0048] Furthermore, if the sliding spare seedling tray 41 is used to supply mat seedlings to the seedling carrier 36, and then multiple seedling boxes containing mat seedlings are placed on the sliding spare seedling tray 41 and planted, even if the mat seedlings on the seedling carrier 36 run out during the work, the seedling boxes placed on the sliding spare seedling tray 41 can be removed and the mat seedlings can be replenished to the seedling carrier 36 of the planting device 6. Similarly, when replenishing fertilizer to the fertilizer applicator, the fertilizer bag can be placed on the rollers 40 and easily transported up to above the wide step 31.

[0049] The outline of the riding rice transplanter 1 has been explained above, but next we will explain the fertilizer applicator, which is a working device provided together with the planting device 6 described above. This fertilizer applicator uses a granular fertilizer applicator 43 that applies granular fertilizer in side stripes (spreading it into the soil to the sides of the seedlings to be planted on the rice field surface), and this granular fertilizer applicator 43 has its main body provided at the rear of the traveling body 4. That is, the granular fertilizer applicator 43 has a base frame 44 that is attached to the fertilizer applicator frame 34 that is provided extending rearward from the step frame 22 described above, and stays 45 are provided at the left and right ends of this base frame 44 so that it can pivot freely in the left and right directions.

[0050] The granular fertilizer applicator 43 is provided with eight hoppers 46 that store the granular fertilizer, a roll case 47 that connects to the bottom of the hopper 46, and a payout mechanism that is built into the roll case 47 and receives the granular fertilizer stored in the hopper 46 and releases the granular fertilizer downward in predetermined amounts as the roll rotates, corresponding to the number of planting rows of the planting device 6. In this case, these are divided into two adjacent sets of four on the left and right, and each set is attached to the left and right stays 45 using a loop-shaped subframe 48 that has a stand that holds it in a fertilizing position, so that when each set is rotated outward, the granular fertilizer remaining in the four hoppers 46 can be released all at once from the outermost hopper 46 and collected.

[0051] Meanwhile, eight connecting pipes 49 are laid horizontally in the front-to-rear direction on the base frame 44 below the eight hoppers 46 and roll cases 47 aligned in the left-to-right direction. Therefore, when the hoppers 46, roll cases 47, etc. are lowered to return them to their normal fertilizing positions after the release of residual fertilizer from the hoppers 46 or other maintenance work is completed, the fertilizer discharge port provided at the bottom of the roll case 47 passes through an insertion hole provided at the upper middle part of the connecting pipes 49 and opens inside the connecting pipes 49, allowing the fertilizer released by the delivery mechanism provided in the roll case 47 to be guided into the connecting pipes 49.

[0052] The front ends of all of the connecting pipes 49 open into a front duct 50 that is installed laterally on the base frame 44, and one left end of the duct 50 is connected to the outlet of an electric blower 51 installed at the left end of the base frame 44, while the other right end is closed. Furthermore, the front end of a fertilizer application hose 52 is connected to the rear end of each connecting pipe 49, and a boot installed at the rear end of the fertilizer application hose 52 is positioned behind a furrow making body installed on the float 38 of the planting device 6 and attached to the float 38, so that granular fertilizer is released into the fertilizer application furrows made by the furrow making body on the rice field surface, and the granular fertilizer can be covered with soil by a soil covering body installed below the float 38.

[0053] A drive case 53 for the fertilizer applicator is provided on the base frame 44 behind the driver's seat 23, and power taken out from a gear case provided midway on the PTO shaft that transmits power to the planting device 6 is transmitted to a friction type transmission built into this drive case 53. The output gear of this friction type transmission is meshed with the input gear of a limiter for preventing overload provided behind the drive case 53, and the output shaft of the limiter is further connected via a coupling to the input shaft of the payout mechanism built into the roll case 47 so as to be drivable.

[0054] Therefore, when planting seedlings with the planting device 6 and simultaneously applying fertilizer from the side using the granular fertilizer applicator 43, the planting work is started by supplying granular fertilizer to the eight hoppers 46 of the granular fertilizer applicator 43. In this case, when supplying granular fertilizer to the hoppers 46, the lids 46a provided on the tops of the four hoppers 46 on the left and right are opened, and several bags of granular fertilizer are supplied at once until the hoppers 46 are full while tearing open the fertilizer bags and leveling the fertilizer by hand so that the granular fertilizer is evenly contained in the four hoppers 46, and finally the lids 46a are closed and the planting and fertilizing work is started.

[0055] Once planting and fertilizing work has begun, granular fertilizer applicator 43 dispenses the granular fertilizer stored in each hopper 46 into connecting pipe 49 using a dispensing mechanism attached to roll case 47, and the amount of fertilizer dispensed can be set using adjustment dial 54 attached to drive case 53. The granular fertilizer that has fallen into connecting pipe 49 moves smoothly through fertilizer application hose 52 attached to the rear end of connecting pipe 49 due to the transport air blown out by blower 51 taken in from the front end of connecting pipe 49, and is ultimately embedded in the soil next to the seedlings to be planted in the rice paddy field.

[0056] The granular fertilizer applicator 43 has been described above as a fertilizer applicator, but when applying a liquid paste fertilizer with a relatively high clay content instead of granular fertilizer to the seedlings planted by the planting device 6, a paste fertilizer applicator 55 is used as the fertilizer applicator. That is, as shown in Figures 12 and 13, a two-stage paste side stripe fertilizer applicator 55 that applies paste fertilizer to shallow and deep layers of soil near the seedlings to be planted has a base frame 56 that is long in the left-right direction attached to the fertilizer applicator frame 34 that extends rearward from the step frame 22 described above, and left and right fertilizer tanks 57 that store paste fertilizer are arranged side by side in the left-right direction on this base frame 56.

[0057] In addition, in the center of the base frame 56, which is below the left and right fertilizer tanks 57, there is a fertilizer clutch that intermittently transmits power transmitted from a gear case installed midway on the PTO shaft that transmits power to the planting device 6 via a transmission shaft to the fertilizer application device 55, a gear transmission that changes the amount of fertilizer applied, and a drive device that has driving parts such as sprockets, chains, or gears that drive the fertilizer pump of the fertilizer application device 55 from the output shaft of the gear transmission, and is partially covered with a cover or the like.

[0058] Therefore, the drive mechanism and the like of the fertilizer applicator 55 are installed at a relatively high position at the rear of the traveling body 4, so that they can be installed in a place that is away from the environment where they are exposed to muddy water splashed by the front wheels 2 and rear wheels 3, etc., and are easy to maintain. The fertilizer pump of the fertilizer applicator 55 uses a positive displacement screw pump to accurately discharge paste fertilizer based on the determined amount of fertilizer to be applied, and these screw pumps are installed as three pump assemblies, four of which are grouped together in a case, below the left and right fertilizer tanks 57 together with the drive mechanism of the fertilizer applicator 55.

[0059] Furthermore, the paste fertilizer applicator 55 has eight nozzles for shallow layers and four nozzles for deep layers that inject the paste fertilizer into the soil, which are attached to the float 38 of the planting device 6 so that the fertilizer application depth from the rice field surface is constant. Also, the outlets at the bottom of the left and right fertilizer tanks 57 are connected by hoses to the suction ports of the left and right shallow layer pump assemblies, and hoses branching from the middle of these hoses also connect the two suction ports of the deep layer pump assemblies to the outlets of the left and right fertilizer tanks 57.

[0060] The four pump discharge ports of the left and right shallow layer pump assemblies are connected to the base ends of the eight shallow layer nozzles by respective pipes, and the four pump discharge ports of the deep layer pump assemblies are connected to the base ends of the four deep layer nozzles by respective pipes. Therefore, when fertilizing the soil at the same time as planting seedlings, when the planting clutch is engaged by operating the quick-up lever provided on the control unit, the fertilizer clutch is also engaged in conjunction with this, and the pump assemblies are driven by the drive device of the paste fertilizer applicator 55.

[0061] When each fertilizing pump in the pump assembly is driven, it sucks in paste fertilizer stored in the fertilizer tank 57 through a suction flow path formed by a hose, and the paste fertilizer is pumped into a discharge flow path formed by a pipe and injected from the tip of each nozzle into the soil near the planted seedlings. In this case, the pump assembly is driven by power taken from the traveling system whose speed is changed by the main shift lever, so that paste fertilizer can be applied to the soil in just the right amount in proportion to the vehicle speed.

[0062] The outline of the paste fertilizer applicator 55 has been explained above, but this paste fertilizer applicator 55 is mounted on a frame 42 that is raised outward beyond the front side steps 29 provided on the left and right sides of the front of the traveling body 4, with left and right supply tanks 58 mounted on the frame 42 with their longitudinal direction in the front-to-back direction so as to overlap below the sliding spare seedling tray 41. In addition, a supply pump with an integrated electric motor is mounted inside the cover 33 that covers the seat frame 21 to which the driver's seat 23 is attached, and the outlets provided at the bottom of the left and right supply tanks 58 are connected by hoses to the suction ports of the supply pumps.

[0063] Furthermore, a hose connects the discharge port of the supply pump to the discharge ports provided at the bottom of the left and right fertilizer tanks 57. Meanwhile, fertilizer supply ports that can supply paste fertilizer are formed at the top of the fertilizer tank 57 and supply tank 58, and lids 57a, 58a are provided to close these supply ports. Therefore, when supplying (replenishing) paste fertilizer to the fertilizer tank 57, which is provided at a relatively high position at the rear of the traveling body 4, for example, a worker standing on the front side step 29 at the front of the traveling body 4 receives a fertilizer bag containing paste fertilizer from an assistant worker standing at the edge of the field and carries it to the rear work step (rear side step 30).

[0064] Then, the outlet of the fertilizer bag with the cap removed is placed facing the fertilizer supply port of the left and right fertilizer tanks 57 with the lids 57a open, and the paste fertilizer contained in the fertilizer bag is poured out from the outlet into the fertilizer tanks 57. However, the work of replenishing the left and right fertilizer tanks 57 is difficult to carry because the fertilizer bags are made of a flexible material such as vinyl, and repeated carrying of the fertilizer bags containing the considerable weight of paste fertilizer is hard work for the worker.

[0065] Therefore, as an alternative method of replenishing paste fertilizer into the fertilizer tank 57 to the above-mentioned replenishing method, the worker stands on the front side step 29 at the front of the traveling body 4 and receives the fertilizer bag from the assistant worker. Next, the worker positions the outlet of the fertilizer bag with the cap removed toward the fertilizer supply port of a replenishing tank 58 located nearby at a relatively low position on the traveling body 4, and allows the paste fertilizer contained in the fertilizer bag to flow out from the outlet and into the replenishing tank 58. This process is repeated several times to fill both left and right replenishing tanks 58 to their full capacity.

[0066] Then, when the supply switch provided on the panel cover 18 of the control section is turned on and operated, the supply pump operates to pump (send) the paste fertilizer stored in the left and right supply tanks 58 to the left and right fertilizer tanks 57. Furthermore, when the left and right fertilizer tanks 57 are filled to capacity by the above operation, the left and right supply tanks 58 become empty, and the operator can then continue the above-mentioned work of supplying paste fertilizer to the left and right supply tanks 58.

[0067] Therefore, if the amount of fertilizer remaining in fertilizer tank 57 becomes low during subsequent planting and fertilizing work, the replenishment switch can be operated in the same way to supply fertilizer stored in replenishment tank 58 to fertilizer tank 57, allowing the planting and fertilizing work to continue efficiently with almost no interruption and reducing the number of times the fertilizer needs to be replenished from the ridges. Of course, if you are willing to put in the effort, you can also replenish paste fertilizer in fertilizer tank 57 directly using a fertilizer bag.

[0068] The above has provided a brief explanation of the granular fertilizer applicator 43 and the paste fertilizer applicator 55 as fertilizer applicators. Next, we will provide an overview of a straight-line automatic steering system that allows the riding rice transplanter 1 to perform work tasks such as planting and fertilizing using a Global Navigation Satellite System (GNSS) based on Real Time Kinematic (RTK) to drive the planter hands-free.

[0069] In other words, the automatic steering device that constitutes this straight-line automatic steering system comprises two GNSS antennas 59, 60, one for position and one for direction, which capture radio waves emitted from positioning satellites, a dual-frequency GNSS receiving module that receives the two types of radio waves captured by the two GNSS antennas 59, 60 and outputs position information, etc., an inertial module that detects the attitude of the traveling body 4, a short-range communication module, and a GNSS controller that controls these modules, all of which are assembled into a unit and placed within a case 62 attached to the top of a gate-shaped support frame 61 that stands upright from the frame 42 of the sliding spare seedling tray 41, for example.

[0070] Additionally, a tablet terminal that receives GNSS correction data using the Ntrip (Networked Transport of RTCM via Internet Protocol) method or displays guidance screens and the like is installed below the monitor panel in the control unit panel cover 18 and is covered with a water-resistant body 63. Furthermore, a drive unit that rotates the steering shaft 15, which is installed in the steering system of the front wheels 2, using a stepping motor via a gear reduction mechanism is attached to a bracket on the steering column 16.

[0071] The automatic steering device composed of the above members calculates the current position and orientation of the traveling vehicle 4 in an automatic control program for straight-line driving executed by the GNSS controller, which is the key to automatic steering, from the GNSS correction data received by the aforementioned two-frequency GNSS receiving module or tablet terminal, or from attitude information obtained from the inertial module.

[0072] Meanwhile, the tablet device runs navigation software and displays the current position and direction of the traveling vehicle 4 transmitted by the GNSS controller on its guidance screen. It also creates a work traveling route for straight traveling based on teaching traveling performed by the worker, and displays on the display the traveling route to be followed by the traveling vehicle 4, its current position, and the deviation between them. Furthermore, it calculates the steering angle of the front wheels 2 to eliminate this deviation based on the deviation, and transmits this value to the GNSS controller.

[0073] When a steering angle command is issued from the tablet terminal, the GNSS controller, based on the automatic steering on / off state commanded by the operator using a start / stop switch provided on the panel cover 18 of the control unit, for example, when automatic steering is selected, passes an excitation current through the stepping motor to rotate the stepping motor so that the steering angle of the front wheels 2 becomes the commanded value. This also rotates the steering shaft 15 via a gear reduction mechanism, steers the front wheels 2 to the commanded steering angle, and enables the traveling body 4 to automatically travel straight, which allows the operator to drive hands-free and reduce fatigue while stably performing straight-line work with high precision.

[0074] The above provides an overview of the configuration of each part of the riding rice transplanter 1 related to the problem to be solved by this invention, but the specific technical means for solving the problem of this invention will be explained below. First, the seat frame 21 that attaches the driver's seat 23, where the operator sits and operates the riding rice transplanter 1, to the traveling body 4 has left and right side plates 21a, 21b fixed to the center near the rear of the chassis frame 10 as shown in Figure 3.

[0075] Furthermore, the middle of a pipe 21c extending in the left-right direction is fixed to the upper front portions of the left and right side plates 21a, 21b, and a U-shaped support plate 21d fixed to the center of this pipe 21c has left and right holes 21e drilled at the tip of the support plate 21d which is bent diagonally upward toward the front side, thereby forming a seat mounting portion provided at the upper portion of the seat frame 21. Furthermore, a wide connecting plate 21f, both ends of which are fixed to the upper middle portions of the left and right side plates 21a, 21b to connect them, is used as a rear support plate 21f that supports the rear portion of the driver's seat 23.

[0076] A large-diameter pipe 21g is fixed between the upper portions of the left and right side plates 21a, 21b near the rear ends, and one end of a hydraulic cylinder 7 that raises and lowers the planting device 6 is attached to the center of this pipe 21g. A hydraulic control valve 64 that controls the raising and lowering operation of this hydraulic cylinder 7 is attached along the plate surface near the front of the right side plate 21a, and a substantially rectangular hole 21h is provided near the front of the left side plate 21b (see Figures 6 and 1).

[0077] A microcomputer unit 65 that controls each part of the riding rice transplanter 1 is attached from the outside left so as to face this hole 21h, and a panel with a 7-segment LED 65a and three switches 65b attached to this unit 65 is configured so that it can be seen and operated from the right side of the hole 21h. Furthermore, a bracket 66 is attached near the center of the bent front part of the rear support plate 21f attached to the upper part of the seat frame 21, and a seating sensor 67 that detects whether or not an operator is seated in the driver's seat 23 is attached to this bracket 66.

[0078] The seating sensor 67 uses a rotation detection type sensor in which, when the detection body 67a is pushed and the rotation shaft rotates, a switch provided in the case 67b is turned on. In this case, when the detection body 67a, which moves from below the rear support plate 21f toward the front, is pushed from above and the rotation shaft rotates by approximately 10 degrees, the switch changes from off to on (see Figures 6 and 7). Furthermore, since the rotation shaft is biased by an internal elastic mechanism to return to its initial position of 0 degrees, if the detection body 67a is not pushed from above, it returns to its mounting position, which is positioned below the upper surface of the rear support plate 21f and slightly diagonally upward (see Figures 10 and 11).

[0079] 4 and 5, the driver's seat 23 is configured so that a seat slide device 68 is attached to the underside of the seat on which the operator sits, allowing the operator to adjust the fore-and-aft movement of the driver's seat 23 while remaining seated. That is, the seat slide device 68 includes a pair of left and right lower rails 70 fixed to the upper surface of a lower bracket 69, a pair of left and right upper rails 71 slidably fitted into the pair of left and right lower rails 70, a lock mechanism 72 attached to one of the upper rails 71 to prevent or allow the upper rail 71 to slide, and an upper bracket 73 that fixes the pair of left and right upper rails 71 to the underside of the seat of the driver's seat 23.

[0080] The pair of left and right lower rails 70 and upper rails 71 described above are configured such that the upper rail 71 is slidably fitted into the lower rail 70, and a set of left and right seat slide rails is used, which are configured, for example, by incorporating steel balls and rollers with retainers at two predetermined locations in the longitudinal direction of both rails so that the upper rail 71 can slide smoothly along the lower rail 70.

[0081] An engagement plate 70a having a number of holes formed in the longitudinal direction and constituting the lock mechanism 72 is fixed to the right seat slide rail along the outer side of the lower rail 70. A locking body 74 having a pawl that simultaneously penetrates three holes formed in the engagement plate 70a is fixed to a lever shaft 75, and a locking plate 71a that rotatably supports the lever shaft 75 is fixed to the upper rail 71.

[0082] Furthermore, a spring 76 is attached to the lever shaft 75, and when an operating portion 75a formed by bending the lever shaft 75 is lifted upward against the biasing force of the spring 76, the engaged state (locked state) in which the claws of the locking body 74 are stuck in the holes of the engagement plate 70a is released, and the upper rail 71 can be set to a disengaged state (unlocked state) in which the claws can be freely moved to any position relative to the lower rail 70. When the operating portion 75a is released, the biasing force of the spring 76 causes the claws of the locking body 74 to stick in the corresponding holes in the engagement plate 70a, and the upper rail 71 can be returned to a state in which its movement cannot be adjusted.

[0083] When a set of seat slide rails equipped with the locking mechanism 72 configured as described above is assembled using weld bolts and nuts to the upper surface of the lower bracket 69 forming a lattice-shaped framework, the front portions of the left and right lower rails 70 are attached to the left and right ends of front bracket pieces 69a formed by bending downward the rear sides of the lower brackets 69. Similarly, the rear portions of the left and right lower rails 70 are attached to the left and right ends of rear bracket pieces 69b.

[0084] Furthermore, the left and right end portions of the front bracket piece 69a and the rear bracket piece 69b are welded to the front and rear portions of the right bracket piece 69c and the left bracket piece 69d, respectively, to frame the lower bracket 69 in a grid pattern. As a result, the left and right lower rails 70, which are the main components of the seat slide device 68, are reinforced by being fixed to the upper surface of the lower bracket 69. Furthermore, the left and right lower rails 70 and the left and right upper rails 71 that fit into the lower rails 70, respectively, are properly attached to the upper surface of the lower bracket 69, thereby maintaining their parallelism and flatness and preventing twisting or bending of the seat slide rails.

[0085] Furthermore, the left and right upper rails 71 that are fitted to the left and right lower rails 70 attached to the upper surface of the lower bracket 69 in this manner have their front ends attached to the left and right ends of the front connecting piece 73a of the upper bracket 73 using weld bolts and nuts, and similarly, the rear ends of the left and right upper rails 71 are attached to the left and right ends of the rear connecting piece 73b, so that the parallelism and flatness of the left and right upper rails 71 can be maintained.

[0086] The driver's seat 23 can be attached by passing four bolts (front, rear, left, and right) provided on the underside of the seat portion through holes drilled in the front connecting piece 73a and rear connecting piece 73b of the upper bracket 73 and fastening them with nuts from below. Note that left and right mounting pieces 69e, 69f facing forward and spaced apart from each other are welded to the front bracket piece 69a of the lower bracket 69 described above near the left-right center, and weld pins 69g, 69h of slightly different lengths are welded to the front of the left and right mounting pieces 69e, 69f and facing right, thereby forming a mounting portion for the seat near the front of the lower bracket 69.

[0087] Therefore, of the weld pins 69g, 69h provided near the front of the lower bracket 69, the slightly longer left weld pin 69h is first passed through the left hole 21e from the left side into the left hole 21e in the left and right holes 21e of the seat mounting portion 21d provided at the top of the seat frame 21, and using this as a guide, the right weld pin 69g is passed through the right hole 21e, and then a snap pin is inserted into this right weld pin 69g to prevent it from coming out, and the driver's seat 23, together with the seat slide device 68, can be attached to the top of the seat frame 21 provided in the center near the rear of the traveling body 4 so that it can be freely folded down toward the steering handle 17 in front.

[0088] The rear bracket piece 69b of the lower bracket 69 is bent downward so that its longitudinal center is recessed, and the left and right sides of the recess are bent so that they bulge upward slightly. Weld pins are welded to the left and right portions of the rear bracket piece 69b that bulge upward so that they protrude downward, and left and right cushion rubbers 77 are press-fitted into these weld pins to attach them. Left and right coil springs (floating springs) 78 are attached with bolts to the underside of the recess in the center of the rear bracket piece 69b, spaced apart from each other but close to the left and right cushion rubbers 77.

[0089] Meanwhile, a loop-shaped operating rod 69i that protrudes diagonally downward and rearward is welded to the bent center of the front bracket piece 69a of the lower bracket 69. Therefore, when an operator sits down and applies weight to the driver's seat 23 as shown in Figure 6, the left and right cushion rubbers 77 and the coil spring 78 provided on the rear bracket piece 69b of the lower bracket 69 come into contact with and are received by the wide rear support plate 21f provided on the upper part of the seat frame 21. In this case, the operating rod 69i of the lower bracket 69 comes into contact with the detection body 67a of the seating sensor 67 and rotates it downward by approximately 10 degrees or more, turning on the switch.

[0090] Conversely, when the operator leaves the seat and no load is applied to the driver's seat 23, the coil spring 78 provided on the rear bracket piece 69b lifts the rear side of the lower bracket 69 upward so that the left and right cushion rubbers 77 move upward away from the rear support plate 21f. In this case, the operating rod 69i of the lower bracket 69 rotates upward, and when the detecting body 67a of the seating sensor 67 rotates less than approximately 10 degrees, the switch is turned off. Furthermore, when the driver's seat 23 is tilted forward, the operating rod 69i moves completely away from the detecting body 67a, and in this case, the detecting body 67a of the seating sensor 67 returns to 0 degrees and assumes an installation position that is positioned below the upper surface of the rear support plate 21f and facing slightly diagonally upward (see Figures 10 and 11).

[0091] The above has explained the technical means for providing a seat slide device 68 on the driver's seat 23. Here, we will briefly explain the work procedure when an operator supplies seedlings and fertilizer to the planting device 6 or fertilizer applicator 43, 55 of the riding rice transplanter 1. As mentioned above, an assistant worker moves seedling boxes or fertilizer bags containing mat seedlings from a farm road or bank to above the wide step 31 using the sliding spare seedling tray 41 on the left or right side, and the operator then stands up on the left or right rear side step 30 (work step) and receives the seedling boxes or fertilizer bags on the sliding spare seedling tray 41.

[0092] If seedling boxes are used, mat seedlings are scooped up on the spot using a scraper and, for example, three mat seedlings are inserted one after another from above onto each of the eight seedling carriers 36 of the raised planting device 6 for replenishment. Furthermore, if granular fertilizer is used, the fertilizer bag is torn or opened using a cutter knife or the like above the hopper 46 with its lid 46a opened in advance, and the fertilizer is poured into the hopper 46 without spilling. If paste fertilizer is used, the cap of the fertilizer bag is removed and the fertilizer is poured into the fertilizer tank 57 above the fertilizer supply port of the fertilizer tank 57 with its lid 57a opened in advance, without spilling.

[0093] When supplying seedlings or fertilizer in this manner, the worker can sit in the driver's seat 23 while driving the vehicle and fold it down, along with the seat slide device 68, toward the steering handle 17 (see Figures 8, 10, 11, and 13), freeing up the space that had previously been occupied by the driver's seat 23 and the seat slide device 68.This means that the worker can move left and right through the open space above the work steps 30-32 without having to make unnecessary movements such as detouring around the floors 24, 25 when carrying the seedlings, fertilizer, etc., and then, when he or she reaches the desired location, can accurately supply the seedlings, fertilizer, etc. to the work equipment at the rear.

[0094] In addition, in the open space (the space occupied by the driver's seat 23 and seat slide device 68) together with the space above the aforementioned work steps 30-32, a wide support plate 21f that supports the rear side of the driver's seat 23 is provided on the top of the seat frame 21 so as to be at approximately the same height as the work steps 30-32, and this support plate 21f can be used as a foothold when the operator tilts the driver's seat 23 toward the steering handle 17 to perform work to supply seedlings, fertilizer, etc. Therefore, the operator can stand on the top surface of the work steps 30-32 or support plate 21f without being obstructed by the seat slide device 68, cushion rubber 77, coil spring 78, or seating sensor 67, and supply seedlings, fertilizer, etc. to the planting device 6 or fertilizer application device provided behind it in a stable position.

[0095] Furthermore, even if the driver's seat 23 is tilted forward, the seat slide device 68 maintains the position of the driver's seat 23 that was adjusted for forward and backward movement when the operator travels for work, etc. Therefore, when resuming work travel after completing resupplying work, the operator simply returns the driver's seat 23 for the seat slide device 68 to its original seated position, without having to adjust the forward and backward movement again. Also, if the driver's seat 23 for the seat slide device 68 is tilted toward the steering handle 17, it is possible to prevent the seat surface of the driver's seat 23 from accumulating dirt and dust or becoming wet with rainwater when planting work, etc. is interrupted.

[0096] Furthermore, if an abnormality occurs in an electrical component such as a potentiometer, switch, or monitor equipped on the riding rice transplanter 1, the 7-segment LED 65a displays the abnormality in an error code, and can be seen through a recessed depression 33a provided in the center of the cover 33 that covers the opening formed above the seat frame 21 and a hole 21h in the left side plate 21b of the seat frame 21, and the three switches 65b can be operated. Therefore, in such a case, by tilting the driver's seat 23 together with the seat slide device 68 toward the steering handle 17, it is possible to reach in through the opening that extends from the rear of the seat mounting portion 21d to the front of the support plate 21f to access these.

[0097] When the driver's seat 23 equipped with the seat slide device 68 is positioned at the rearmost position as shown in Fig. 6 and then tilted forward as shown in Fig. 10, the driver will maintain the tilted state even if he or she lets go of the front steering wheel 17 while leaning on it. Also, when the driver's seat 23 is positioned at the frontmost position as shown in Fig. 7 and then tilted forward as shown in Fig. 11, the upper end of the seat back will slightly lean on the front steering wheel 17, causing the driver's seat 23 to return to the rear. However, even in this case, the driver's seat 23 can maintain the tilted state even if he or she lets go of the steering wheel by designing the driver's seat 23 and the seat slide device 68 in consideration of the center of gravity.

[0098] The seating sensor 67 provided in the driver's seat 23 is provided to encourage the operator to sit in the driver's seat 23 by causing a control device such as the microcomputer unit 65 to issue a warning using a buzzer or the like when the operator leaves the driver's seat 23 for some reason while the automatic steering device is performing automatic straight-line control when the riding rice transplanter 1 is planting seedlings or applying fertilizer, as described above. For example, if the seating sensor 67 detects that the operator has continuously left the seat, the control device may prioritize safety and stop the engine 12, etc.

[0099] Therefore, the riding rice transplanter 1 can use an automatic steering device to perform planting work in a straight line with consistent work intervals while ensuring safety, and even an amateur can be expected to perform work driving at the same level as an expert. In this case, the seat sensor 67 uses a rotation detection sensor that is inexpensive, reliable, and has stable performance, and because this seat sensor 67 is located below the support plate 21f, there is no risk of the seat sensor 67 being damaged or the operator being injured when the operator places their feet on the support plate 21f while tilting the driver's seat 23 toward the steering handle 17 to perform work such as supplying seedlings or fertilizer.

[0100] Furthermore, the seating sensor 67 detects the operator sitting in the driver's seat 23 by passing an operating rod 69i hanging down from the driver's seat 23 through an opening that extends from the rear of the seat mounting portion 21d to the front of the support plate 21f, and then abutting the tip of the operating rod 69i against the detecting body 67a of the seating sensor 67.Therefore, the wiring to the control device that issues an alarm for leaving the seat from the seating sensor 67 does not require measures such as routing along the seat mounting portion 21d of the driver's seat 23, and can be simply routed, for example, toward the microcomputer unit 65 provided on the left side panel 21b of the seat frame 21.

[0101] Next, the mounting structure of the driver's seat 23 that does not have the seat slide device 68 will be explained. As shown in Figure 14, a seat mounting bracket 79 is prepared, which is framed in a grid pattern by left and right bracket pieces 79a, front bracket pieces 79b welded to the front of the left and right bracket pieces 79a, and rear bracket pieces 79c welded to the rear of the left and right bracket pieces. The mounting bracket 79 is then attached to the driver's seat 23 by passing four bolts (front, rear, left, and right) provided on the underside of the seat portion through holes drilled in the left and right bracket pieces 79a and fastening them from below with nuts.

[0102] The mounting bracket 79 has four mounting holes 79e drilled at intervals in the front-to-rear direction in seat mounting portions 79d bent downward toward the front of the left and right bracket pieces 79a. Furthermore, a weld pin is welded to the rear of each of the left and right bracket pieces 79a, and left and right cushion rubbers 77 are press-fitted into these downward-facing weld pins for mounting. Then, left and right coil springs (floating springs) 78 are attached with bolts spaced apart from each other to the underside of a recess in the center of the rear bracket piece 79c.

[0103] Meanwhile, the seat mounting portion 21d provided on the upper part of the seat frame 21 has left and right holes 21e as described above, and by passing a mounting pin 80 through these left and right holes 21e and through any one of the four mounting holes 79e provided in the left and right bracket pieces 79a of the mounting bracket 79, and finally securing the mounting pin 80 with a snap pin, the driver's seat 23 can be mounted and installed so that its mounting position in the fore-and-aft direction is freely adjustable to the mounting portion 21d provided on the upper part of the seat frame 21. In addition, a loop-shaped operating rod 79f that protrudes diagonally downward and rearward is welded to the center of the front bracket piece 79b of the mounting bracket 79.

[0104] A bracket 66 is attached to the center of the bent front part of the rear support plate 21f provided on the upper part of the seat frame 21, and the seating sensor 67 attached to this bracket 66 has a detection body 67a attached to its rotating shaft that is slightly longer so that the tip of the operating rod 79f mentioned above will properly abut against the detection body 67a of the seating sensor 67 regardless of the adjustment of the fore-and-aft mounting position of the driver's seat 23.

[0105] That is, when the rear part of the driver's seat 23 is lifted by the lifting spring 78, the detection body 67a changes from an x ​​rotation position (0 degrees) where the tip of the operating rod 79f is in contact or not in contact, to a y rotation position (10 degrees) when the operator sits in the driver's seat 23, compressing the lifting spring 78, and as a result, the tip of the operating rod 79f comes in contact and changes to a y rotation position (10 degrees), changing the switch from off to on, and when the operator sits down completely in the driver's seat 23, the cushion rubber 77 is received by the support plate 21f and changes to a z rotation position (20 degrees).

[0106] In this case, if the relative positions and the mounting angle of the seating sensor 67 are set so that the driver is half-seated in the driver's seat 23, which rotates from off to on and assumes a y-rotation position, can be maintained regardless of changes to the fore-and-aft mounting position of the driver's seat 23, the detection accuracy of the seating sensor 67 will be improved, and work driving can be carried out safely even when using an automatic steering device to perform automatic straight-line control, etc. [Explanation of symbols]

[0107] 1. Ride-on rice transplanter (agricultural work vehicle) 4 Running body 6 Planting equipment (work equipment) 17 Steering wheel 21 Seat frame 21d Seat mounting part 21f Support plate 23 Driver's seat 24 Center Floor (Floor) 25 Side Floor (Floor) 30 Rear side step (work step) 31 Wide step (work step) 32 Rear center step (work step) 67 Seat sensor 67a Detected object 68 Seat slide device 69i control rod 77 Cushion Rubber 78 Coil spring (floating spring) 79f operation lever

Claims

1. An agricultural work vehicle in which a driver's seat is located above a seat frame mounted in the center near the rear of the running body, and work steps are provided on both the left and right sides of the driver's seat to the rear, and a worker stands up from a floor mounted in front of the work steps to supply seedlings, fertilizer, etc. to work equipment mounted at the rear or rear of the running body.The agricultural work vehicle is configured such that an attachment part that pivots the front of the driver's seat and a support plate that supports the rear of the driver's seat and is equipped with cushion rubber and a levitation spring are provided at the top of the seat frame, and the driver's seat can be freely tilted toward the steering handle mounted in front of it, and the tip of an operating rod that hangs down from the center of the driver's seat is abutted against the detecting body of a rotation detection type seating sensor mounted below the support plate, thereby detecting the worker sitting in the driver's seat.

2. 2. The agricultural work vehicle according to claim 1, wherein a seat slide device is attached to the underside of the driver's seat so that the operator can adjust the driver's seat forward and backward while remaining seated, and the driver's seat is configured to be able to be tilted down along with the seat slide device toward a steering handle provided in front of it.

3. 2. The agricultural work vehicle according to claim 1, wherein the driver's seat is adapted to have its longitudinal mounting position adjusted relative to a mounting portion provided on an upper portion of the seat frame, and the length of the seat occupancy sensor detector is set long so that the tip of the operating rod abuts against the seat occupancy sensor detector regardless of the adjustment of the longitudinal mounting position of the driver's seat.

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