Paddy field farming machine

Abstract

To enable a worker to operate an operation arm without difficulty when moving a paddy field work machine out of a farm field over ridges.SOLUTION: An operation arm 53 is provided in the front part of a machine body in a manner to change a posture to a non-use posture B1 in which the operation arm is erected in the front part of the machine body and to a use posture B2 in which the operation arm is extended from the front part of the machine body to a front side. A speed regulation part 87 is provided so that when the operation arm 53 is operated to the use posture B2 in a state that a second speed changer 42 is operated to a low speed side, an operation of a first speed changer 41 to a high speed side is regulated at a first low speed position, and when the operation arm 53 is operated to the use posture B2 in a state that the second speed changer 42 is operated to a high speed side, an operation of the first speed changer 41 to a high speed side is regulated at a second low speed position. The first low speed position and the second low speed position are speed positions that are different from each other.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a paddy field working machine such as a riding rice transplanter or a riding direct seeding machine. [Background technology]

[0002] In a riding rice transplanter, which is an example of a paddy field working machine, as disclosed in Patent Document 1, an operating arm is provided at the front of the machine body and is configured so that the operating arm can be changed between a non-use position in which it stands up at the front of the machine body and a use position in which it extends forward from the front of the machine body.

[0003] When working in the field, the operating arm is operated to the non-use position. When taking the riding rice transplanter out of the field and over the ridge, the operator gets off the machine, stands in front of the machine, and operates the operating arm to the use position. By holding the operating arm in the use position, the operator can change the direction of the machine while preventing the front of the machine from lifting up.

[0004] In Patent Document 1, when the operating arm is operated to the use position, the traveling transmission is configured to be operated to the low speed side. As a result, when the riding rice transplanter is taken out of the field and over the ridge, the operator can operate the operating arm without difficulty because the riding rice transplanter travels at a low speed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-130124 A Summary of the Invention [Problem to be solved by the invention]

[0006] When moving a paddy field working machine out of the field and over the ridges, the operator stops the machine by operating the travel transmission to the stop position, gets off the machine, stands in front of the machine and operates the operating arm to the usage position, and then operates the travel transmission from the stop position to the high-speed side to move the machine forward.

[0007] In the above-mentioned state, when the operating arm is operated to the use position, the configuration of Patent Document 1 in which the traveling transmission is operated to the low speed side can be rephrased as, when the operating arm is operated to the use position, even if the traveling transmission is operated to the high speed side from the stop position, the traveling transmission will not be operated to the high speed side beyond a predetermined low speed position.

[0008] The present invention aims to configure a paddy field working machine equipped with a first transmission and a second transmission for traveling so that an operator can effortlessly operate the operating arm when moving the paddy field working machine out of the field and over a ridge. [Means for solving the problem]

[0009] The paddy field working machine of the present invention is equipped with a first transmission for traveling, a second transmission for traveling, an operating arm provided at the front of the machine body so as to be able to change its position between a non-use position in which it stands up at the front of the machine body and a use position in which it extends forward from the front of the machine body, and a speed limiting unit which, when the operating arm is operated to the use position with the second transmission operated to the low speed side, restricts operation of the first transmission to the high speed side to a first low speed position, and when the operating arm is operated to the use position with the second transmission operated to the high speed side, restricts operation of the first transmission to the high speed side to a second low speed position, and the first low speed position and the second low speed position are different speed positions.

[0010] According to the present invention, in a paddy field working machine provided with a first transmission and a second transmission for traveling, a first low speed position and a second low speed position which are different from each other are set as restrictions for the first transmission depending on the shift position of the second transmission.

[0011] As a result, when the operating arm is operated to the use position with the second speed change device operated to the low speed side, operation of the first speed change device to the high speed side is restricted to the first low speed position. When the operating arm is operated to the use position with the second speed change device operated to the high speed side, operation of the first speed change device to the high speed side is restricted to the second low speed position different from the first low speed position.

[0012] According to the present invention, by setting the gear position of the second transmission device according to the condition of the ridge when the paddy field working machine is taken out of the field and over the ridge, the operator can easily operate the first transmission device to an appropriate gear position, so that when taking the paddy field working machine out of the field and over the ridge, the operator can operate the operating arm without difficulty.

[0013] In the present invention, it is preferable that the second low speed position is set to a speed lower than that of the first low speed position.

[0014] When the operating arm is operated to the use position, and operation of the first transmission to the high speed side is restricted, if the second transmission is operated to the low speed side, the traveling speed of the machine will be sufficiently low. On the other hand, if the second transmission is operated to the high speed side, the traveling speed of the machine will not be very low. As a result, the running speed of the vehicle when the second transmission is operated to the low speed side and the operating arm is operated to the use position may be significantly different from the running speed of the vehicle when the second transmission is operated to the high speed side and the operating arm is operated to the use position.

[0015] According to the present invention, the second low speed position is set to a speed lower than the first low speed position, so that when the operating arm is operated to the usage position with the second variable speed device operated to the high speed side, operation of the first variable speed device to the high speed side is regulated by the sufficiently low second low speed position. This results in a small speed difference between the running speed of the vehicle when the operating arm is operated to the use position with the second speed change device operated to the low speed side and the running speed of the vehicle when the operating arm is operated to the use position with the second speed change device operated to the high speed side.

[0016] According to the present invention, when a first low speed position and a second low speed position which are different from each other are set as restrictions for the first transmission device depending on the shift position of the second transmission device, it is possible to prevent the above-mentioned speed difference from becoming larger than necessary, which is advantageous in that it makes it easier for an operator to operate the first transmission device to an appropriate shift position.

[0017] In the present invention, it is preferable that a first gearshift operating device is provided that can manually operate the first gear change device, and the speed restriction unit restricts operation of the first gearshift operating device to the high speed side at the first low speed position and the second low speed position.

[0018] According to the present invention, when the operating arm is operated to the use position, operation of the first gearshift operating device, which can manually operate the first gear shift device, toward the high speed side is restricted at the first low speed position and the second low speed position. As a result, when the operating arm is operated to the usage position, the operator can recognize that operation of the first shift operating device to the high speed side is restricted at the first low speed position (second low speed position), and therefore can easily recognize that the first shift device is restricted at the first low speed position (second low speed position).

[0019] In the present invention, it is preferable that a second gear change operating device is provided that can manually operate the second gear change device, and the speed restriction unit restricts operation of the first gear change device to the high speed side at the first low speed position and the second low speed position based on the operating position of the second gear change operating device.

[0020] According to the present invention, when the operating arm is operated to the use position, operation of the first transmission device toward the high speed side is restricted at a first low speed position (second low speed position) based on the operating position of a second shift operating device that can artificially operate the second transmission device. As a result, when the operator operates the operating arm to the usage position, he or she can easily determine by visually checking the second shift operating device whether operation of the first shift device to the high speed side is restricted to the first low speed position, or whether operation of the first shift device to the high speed side is restricted to the second low speed position.

[0021] In the present invention, it is preferable that a first adjustment section capable of adjusting the first low speed position to a higher or lower level, and a second adjustment section capable of adjusting the second low speed position to a higher or lower level are provided.

[0022] According to the present invention, by adjusting the first low speed position with the first adjustment unit, the traveling speed of the machine body when the second transmission is operated to the low speed side and the operating arm is operated to the use position can be adjusted to an appropriate value depending on the working conditions, field conditions, etc. By adjusting the second low-speed position with the second adjustment unit, the traveling speed of the machine body when the second transmission is operated to the high-speed side and the operating arm is operated to the usage position can be adjusted to an appropriate value depending on the working conditions, field conditions, etc.

[0023] In the present invention, it is preferable that a stop operation unit capable of stopping a working device supported on the machine body is provided on the operating arm.

[0024] When moving a paddy field working machine out of a field and over a ridge, the operator may hold the operating arm in the usage position, operate the working device while driving the paddy field working machine out of the field and over the ridge, and stop the working device when it reaches the ridge. With riding rice transplanters, the above-mentioned work is sometimes called planting work.

[0025] According to the present invention, when an operator is performing planting work with a riding rice transplanter while holding the operating arm in the usage position, when the working device reaches the ridge, the operator can stop the working device by operating the stop operating part. According to the present invention, a stop operation unit capable of stopping the working device is provided on the operating arm, so that a worker holding the operating arm can easily operate the stop operation unit, and the working device can be stopped without delay.

[0026] In the present invention, a lifting mechanism is provided that supports the working device on the machine body so that it can be raised and lowered, and it is preferable that the lifting mechanism raises the working device to an upper limit position of a lifting range when the stop operating unit is operated.

[0027] When a paddy field working machine is driven from a field to cross a ridge, the front of the machine body is raised, and there is a possibility that the working implement supported by the machine body may come into contact with the ridge. According to the present invention, when the stop operating unit is operated, the lifting mechanism, which supports the work equipment so that it can be raised and lowered on the machine body, operates to raise the work equipment to its upper limit position, so that even if the machine body is in a front-upward state as described above, the work equipment can be prevented from coming into contact with the ridge.

[0028] In the present invention, it is preferable that the speed limiting unit has a limiting unit capable of restricting operation of the first transmission device toward the high speed side, a linkage mechanism connected between the operating arm and the limiting unit and moving the limiting unit toward a position where operation of the first transmission device toward the high speed side can be restricted as the operating arm is operated to the usage position, an adaptor provided in the linkage mechanism, and a setting unit that sets the limiting unit to a first state in which it is positioned at a position corresponding to the first low speed position, and a second state in which it is positioned at a position corresponding to the second low speed position, based on the operating position of the second transmission device.

[0029] According to the present invention, the speed regulating unit includes a regulating unit, a linking mechanism, an adapting unit, and a setting unit. When the operating arm is operated to the use position, the operation of the operating arm is transmitted to the restricting portion via the linkage mechanism, and the restricting portion is operated to the first state or the second state.

[0030] In this case, when the second gear change device is operated to the low speed side, the setting unit places the restricting portion in the first state, so that operation of the first gear change device to the high speed side is restricted at the first low speed position. When the second speed change device is operated to the higher speed side, the setting portion places the restricting portion in the second state, so that operation of the first speed change device to the higher speed side is restricted at the second low speed position. In the above-mentioned state, the position of the restricting portion in the first state is different from the position of the restricting portion in the second state, and therefore this position difference is absorbed by the accommodation portion provided in the linkage mechanism.

[0031] According to the present invention, a mechanically configured speed regulating unit can be obtained that, by using a regulating unit, a linking mechanism, an adapting unit, and a setting unit, can smoothly regulate operation of the first transmission device to the high speed side at the first low speed position and the second low speed position.

[0032] In the present invention, it is preferable that the vehicle be provided with a brake for driving, a brake operating device capable of manually operating the brake, and a low speed linkage unit that operates the first transmission to a stop position or a third low speed position that is slower than the first low speed position and the second low speed position when the brake is operated to a braking state by the brake operating device.

[0033] When taking the paddy field working machine out of the field and over the ridges, the worker on board the machine operates the brake operating device to stop the machine, and after getting off the machine, operates the operating arm to the usage position. According to the present invention, the first transmission is operated to the stop position or the third low speed position by operating the brake to the braking state using the brake operating device, so that the operator simply operates the first transmission from the stop position or the third low speed position to the high speed side to move the machine forward, and operation of the first transmission from the stop position or the third low speed position to the high speed side is regulated at the first low speed position (second low speed position). As a result, when the paddy field working machine is moved out of the field and over the ridges, the first transmission is operated in advance to the stop position or the third low speed position, so that the machine's travel speed can be increased smoothly from a speed slower than the first low speed position (second low speed position).

[0034] In the present invention, it is preferable to have a brake for driving, a brake holding unit that can be operated to a holding state in which the brake is held in a braking state and a holding release state in which the holding state is released, and a brake linkage unit that operates the brake holding unit to the holding release state when the operating arm is operated to the use position.

[0035] Paddy field working machines are sometimes provided with a brake holding section that can be operated between a holding state, in which a travel brake is held in a braking state, and a holding release state, in which the holding state is released. When taking the paddy field working machine out of the field and over the ridges, the operator on board the machine sets the brake holding part to a holding state to hold the brake in the braking state, and after getting off the machine, operates the operating arm to the usage position, after which the brake holding part is set to a release state.

[0036] According to the present invention, when the operating arm is operated to the usage position, the brake holding portion is operated to the release state by the brake linkage portion, so that the operator does not need to set the brake holding portion to the release state, resulting in good operability. [Brief description of the drawings]

[0037] [Figure 1] FIG. 2 is a left side view of the riding rice transplanter. [Diagram 2] FIG. 2 is a front view of a riding rice transplanter. [Diagram 3] 2 is a schematic diagram showing the interconnected state of an engine, a clutch, a continuously variable transmission and an auxiliary transmission, a speed change lever and an auxiliary speed change lever, an operating arm, etc. [Figure 4] This is a right side view of the front part of the riding rice transplanter. [Diagram 5] FIG. 4 is a bottom view near the base of the operating arm. [Figure 6] FIG. 2 is a left side view of the front part of the riding rice transplanter. [Figure 7] 4 is a left side view of the vicinity of the base of the shift lever and the sub shift lever. FIG. [Figure 8] 4 is a front view of the vicinity of the base of the shift lever and the sub shift lever. FIG. [Figure 9] 11 is a left side view of the shift lever and the vicinity of a base of the sub-shift lever when the sub-shift lever is operated to a low speed position. FIG. [Figure 10] 1 is a left side view of the shift lever and the vicinity of a base of the sub-shift lever when the sub-shift lever is operated to a high-speed position. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Figures 1 to 10 show a riding rice transplanter, which is an example of a paddy field working machine, and in Figures 1 to 10, F indicates the forward direction, B indicates the backward direction, U indicates the upward direction, D indicates the downward direction, R indicates the right direction, and L indicates the left direction.

[0039] (Overall configuration of riding rice transplanter) As shown in Figure 1, the riding rice transplanter has a body 3 on which right and left front wheels 1 and right and left rear wheels 2 are provided, and a link mechanism 4 (corresponding to a lifting mechanism) is supported so as to be swingable up and down and extends to the rear at the rear of the body 3, and a hydraulic cylinder 5 (corresponding to a lifting mechanism) is provided to raise and lower the link mechanism 4.

[0040] A seedling planting device 6 (corresponding to a work device) is supported at the rear of the link mechanism 4, a fertilizer application device 7 (corresponding to a work device) is provided between the rear of the body 3 and the seedling planting device 6, and a ground leveling device 8 (corresponding to a work device) is supported at the lower front side of the seedling planting device 6.

[0041] 1 and 2, support frames 59 are provided on the right and left parts of the front of the body 3, and spare seedling trays 73 are supported on the support frames 59. A horizontal frame (not shown) is connected across the upper parts of the right and left support frames 59, and a support frame 82 is connected to the left and right central parts of the horizontal frames, and a positioning unit 21 is attached to the support frame 82.

[0042] The positioning unit 21 is provided with a receiving device (not shown) that acquires position information via a satellite positioning system, and an inertial measurement unit (not shown) that detects the inclination (pitch angle and roll angle) of the aircraft 3, and outputs positioning data indicating the position of the aircraft 3.

[0043] A gyro sensor (not shown) capable of detecting the angular velocity of the yaw angle of the aircraft 3 (the turning angle of the aircraft 3), and an acceleration sensor (not shown) capable of detecting acceleration in three mutually perpendicular axial directions are provided, and the position and orientation of the aircraft 3 are detected by the positioning unit 21, the gyro sensor and the acceleration sensor.

[0044] (Configuration of seedling planting device) As shown in FIG. 1, the seedling planting device 6 is provided with a planting transmission case 9, a rotating case 10, a planting arm 11, a float 12, a seedling stand 13, and the like.

[0045] A rotating case 10 is rotatably supported on the right and left rear parts of the two planting transmission cases 9, and a planting arm 11 is supported on both ends of the rotating case 10. A seedling stand 13 is supported so that it can move back and forth in the left and right direction. As the seedling stand 13 is driven to move back and forth in the left and right direction, the rotating case 10 is driven to rotate, and the planting arm 11 alternately takes out seedlings from the bottom of the seedling stand 13 and plants them on the rice field surface.

[0046] (Configuration of fertilizer application device) As shown in FIG. 1, the fertilizer application device 7 is provided with a hopper 15, a delivery section 16, a blower 17, a furrow former 18, a hose 19, and the like.

[0047] A hopper 15 for storing fertilizer and a delivery section 16 are supported on the rear side of the driver's seat 20 in the machine body 3, and a blower 17 is provided on the left outer side of the delivery section 16. A furrow former 18 is attached to the float 12, and four furrow formers 18 are provided, and four hoses 19 are connected between the delivery section 16 and the furrow formers 18.

[0048] Fertilizer in a hopper 15 is delivered by a delivery section 16 and is supplied to a furrow former 18 through a hose 19 by the conveying wind of a blower 17. As furrows are formed on the surface of the rice field by the furrow former 18, fertilizer is supplied from the furrow former 18 to the furrows on the surface of the rice field.

[0049] (Configuration of ground leveling device) As shown in Figure 1, right and left support cases 14 supported by the seedling planting device 6 extend toward the front, and a drive shaft (not shown) is rotatably supported across the front of the support cases 14, with a number of leveling bodies (not shown) attached to the drive shaft.

[0050] The power of the seedling planting device 6 is transmitted from the planting transmission case 9 to the drive shaft via a transmission chain (not shown) inside the support case 14, and the drive shaft and the leveling body are rotated counterclockwise in Figure 1, and the field surface is leveled by the leveling body.

[0051] (Configuration of transmission system to front and rear wheels) As shown in FIGS. 1 and 2, a support frame 23 is connected to a transmission case 22 disposed at the front of the fuselage 3 and extends forward, and an engine 29 is supported by the support frame 23.

[0052] A bonnet 24 covering an engine 29 is provided at the front of the vehicle body 3. A steering handle 25 for steering the front wheels 1, a speed change lever 31 for traveling (corresponding to a first speed change device that can be operated manually), a sub-speed change lever 32 for traveling (corresponding to a second speed change device that can be operated manually), and a lift lever 27 for operating the hydraulic cylinder 5 are arranged on top of the bonnet 24.

[0053] 1 and 3, right and left front axle cases 39 are connected to the right and left parts of the transmission case 22, and the right and left front wheels 1 are steerably supported on the right and left front axle cases 39. A rear axle case 40 is supported on the rear of the body 3, and the right and left rear wheels 2 are supported on the rear axle case 40.

[0054] 3 and 6, a hydrostatic type continuously variable transmission 41 (corresponding to a first transmission for traveling) is connected to the left part of the transmission case 22. A transmission belt 44 is attached between the output pulley 29a of the engine 29 and an input pulley 41a of the continuously variable transmission 41, and a tension pulley 45 is provided for the transmission belt 44. The continuously variable transmission 41 is capable of continuously changing speed from a neutral position N1 (corresponding to a stop position) to the forward side and the reverse side.

[0055] The power of the engine 29 is transmitted to the continuously variable transmission 41 via a transmission belt 44, and the power of the continuously variable transmission 41 is transmitted from an auxiliary transmission 42 (corresponding to a second transmission for traveling) inside the transmission case 22 and a front wheel differential mechanism 50 to the front wheels 1 via a transmission shaft (not shown) inside the front axle case 39. The auxiliary transmission 42 is configured to be capable of changing speed between two stages: a high speed position H and a low speed position L.

[0056] The power of the auxiliary transmission 42 is transmitted from the transmission shaft 51 to the rear axle case 40, and then transmitted to the rear wheels 2 via a transmission shaft (not shown) and a transmission gear (not shown) inside the rear axle case 40.

[0057] (Lift lever function) The lift lever 27 shown in FIG. 2 can be operated to a neutral position, an elevated position above the neutral position, a descending position below the neutral position, a right marker position rearward of the neutral position, and a left marker position forward of the neutral position, and is biased to the neutral position.

[0058] By operating the lifting lever 27, a control valve (not shown) that supplies and discharges hydraulic oil to the hydraulic cylinder 5, a planting clutch (not shown) (corresponding to a work clutch) that can transmit power to the seedling planting device 6 and the ground leveling device 8, a fertilization clutch (not shown) (corresponding to a work clutch) that transmits power to the fertilization device 7, and an operating part (not shown) that operates the right and left markers (not shown) are operated as described below.

[0059] The riding rice transplanter is provided with a lifting control function for the seedling planting device 6, which will be described below. As shown in Figure 1, a float 12 is supported by the seedling planting device 6 so that it can rise and fall, and based on the detection of the height of the seedling planting device 6 relative to the float 12 that touches the paddy field surface, the hydraulic cylinder 5 is raised and lowered by the control valve so that the height of the seedling planting device 6 from the paddy field surface is maintained at a set height. This maintains the planting depth of the seedlings by the planting arm 11 at the set depth.

[0060] When the lift lever 27 is operated to the raised position, the planting clutch and the fertilizer clutch are disengaged, and the seedling planting device 6, the soil leveling device 8, and the fertilizer device 7 are stopped. Taking priority over the lift control function, the hydraulic cylinder 5 is raised by the control valve, and the seedling planting device 6 is raised to the upper limit position of the lift range of the link mechanism 4.

[0061] When the lift lever 27 is operated to the lowered position, the planting clutch and fertilizer clutch are maintained in the disconnected state, while the hydraulic cylinder 5 is lowered by the control valve, and when the float 12 touches the rice field surface, the lift control function is activated.

[0062] When the lift lever 27 is operated to the lowered position and then operated to the lowered position again, the lift control function is activated, the planting clutch and the fertilizer clutch are operated to a transmission state, and the seedling planting device 6, the ground leveling device 8, and the fertilizer application device 7 are activated.

[0063] When the lift lever 27 is operated to the right marker position, the operation unit operates the right marker to a position where it touches the paddy field surface. When the lift lever 27 is operated to the left marker position, the operation unit operates the left marker to a position where it touches the paddy field surface.

[0064] (Configuration of the front wheel steering system) 4 and 5, a handle post 30 is connected to and extends upward from the upper surface of the transmission case 22. A hydraulic power steering unit 35 is mounted in the middle between the top and bottom of the handle post 30, and a steering handle 25 is rotatably supported on the upper end of the handle post 30.

[0065] A steering member 36 is supported at the bottom of the transmission case 22 so as to be swingable about an axis P2 along the vertical direction, and a tie rod 38 is connected between the steering member 36 and the right and left front wheels 1.

[0066] When the steering handle 25 is rotated, the steering member 36 is swung about the axis P2 to steer the front wheels 1, and the rotation of the steering handle 25 is assisted by the power steering unit 35.

[0067] (Configuration of the operation system of the continuously variable transmission) As shown in FIGS. 6, 7 and 8, a flat support member 26 is connected to the upper left portion of the handle post 30, and a support shaft 26a is provided on the support member 26 along the left-right direction.

[0068] A speed change member 37 having a sector shape in side view with multiple recesses formed on its upper side is provided, and a boss portion 37b of the speed change member 37 is rotatably attached to a support shaft 26a of the support member 26, so that the speed change member 37 is supported so as to be swingable around an axis P1 along the left-right direction. An arm portion 37c and a receiving portion 37d are connected to the boss portion 37b of the speed change member 37.

[0069] The lower portion of the shift lever 31 is supported by a bracket 37a of the shift member 37, and the shift lever 31 is supported by the shift member 37 so as to be operable across a range of positions including a neutral position N1, a maximum forward speed position FA, and a maximum reverse speed position RA.

[0070] A retaining member 43 made of a leaf spring is supported on the upper part of the support member 26, and a roller 43a at the rear end of the retaining member 43 engages with a recess in the shifting member 37. By the roller 43a of the retaining member 43 engaging with the recess in the shifting member 37, the shift lever 31 is retained at a desired position between the maximum forward speed position FA and the maximum reverse speed position RA.

[0071] A support shaft 46 is supported on the left part of the lower part of the handle post 30 so as to be rotatable about an axis P3 along the left-right direction, and extends outward to the left side. An intermediate member 47 having an angle shape in a side view is connected to the support shaft 46, and the intermediate member 47 is supported integrally with the support shaft 46 so as to be swingable (rotatable) about the axis P3.

[0072] A linking rod 48 is connected to the arm portion 37c of the speed change member 37 and extends downward, and a lower portion of the linking rod 48 is connected to the relay member 47. The arm portion 41b is coupled to a speed change shaft (not shown) (trunnion shaft) of the continuously variable transmission 41, and a linking rod 49 is connected between the relay member 47 and the arm portion 41b of the continuously variable transmission 41.

[0073] When the speed change lever 31 is operated to the neutral position N1, the continuously variable transmission 41 is operated to the neutral position N1. When the shift lever 31 is operated from the neutral position N1 toward the highest forward speed position FA, the linking rod 48 is pulled toward the shift lever 31, the relay member 47 and the support shaft 46 swing (rotate) clockwise in Figure 6, and the linking rod 49 is pushed toward the continuously variable transmission 41, causing the continuously variable transmission 41 to move forward.

[0074] When the shift lever 31 is operated from the neutral position N1 toward the highest reverse speed position RA, the linking rod 48 is pushed toward the relay member 47, causing the relay member 47 and the support shaft 46 to swing (rotate) counterclockwise in Figure 6, and the linking rod 49 is pulled toward the relay member 47, causing the continuously variable transmission 41 to be operated to the reverse side.

[0075] (Configuration of the auxiliary transmission operating system) 3, 6, 7 and 8, the operating shaft 52 is supported by the support member 26 so as to be rotatable about an axis P5 along the left-right direction, and the sub-speed change lever 32 is connected to the left end of the operating shaft 52. A linking rod 58 is connected between the left end of the operating shaft 52 and the sub-speed change device 42.

[0076] The sub-speed change lever 32 can be operated to a neutral position N2, a low speed position L, or a high speed position H, and by operating the sub-speed change lever 32, the sub-transmission device 42 is operated to the neutral position N2, the low speed position L, or the high speed position H.

[0077] (Brake pedal configuration) As shown in FIGS. 1 and 2, a floor 28 is provided extending from the right and left sides of the bonnet 24 to the rear side of the bonnet 24.

[0078] 2 and 3, a brake pedal 55 (corresponding to a brake operating tool) is supported on the right side of the transmission case 22 so as to be able to swing up and down, and the brake pedal 55 is disposed on the right side of the bonnet 24 on the floor 28. A brake (not shown) capable of braking the front wheels 1 and the rear wheels 2 is provided inside the transmission case 22, and the brake is operated into a braking state by stepping on the brake pedal 55.

[0079] A brake lever 56 (corresponding to a brake operating tool) is connected to the brake pedal 55 and extends forward, so that an operator standing in front of the machine body 3 can reach out and hold the brake lever 56 to operate the brake pedal 55. A lock lever 57 (corresponding to a brake retaining part) is provided on the floor 28.

[0080] By applying a lock lever 57 to the brake pedal 55 and the brake lever 56 in a depressed state (braking state), the brake pedal 55 and the brake lever 56 can be held in the depressed state (braking state) (holding state).

[0081] By releasing the lock lever 57 from the brake pedal 55 and the brake lever 56, the brake pedal 55 and the brake lever 56 can be operated to a depressed state (braking state) and a released state (braking release state) (hold release state).

[0082] (Structure connecting the brake pedal, gear shift lever, and continuously variable transmission) 3 and 6, the link shaft 60 is supported rotatably about an axis P6 along the left-right direction between the support frame 23 and the transmission case 22. A link rod 61 is connected between the right portion of the link shaft 60 and the brake pedal 55.

[0083] 6 (the side where the tension pulley 45 is pressed against the transmission belt 44). A tension type clutch 63 is provided between the output pulley 29a of the engine 29 and the input pulley 41a of the continuously variable transmission 41. The tension type clutch 63 is formed by the transmission belt 44, the tension pulley 45, and the linking shaft 60.

[0084] The tension pulley 45 is pressed against the transmission belt 44 by the spring 62, so that the power of the output pulley 29a of the engine 29 is transmitted to the input pulley 41a of the continuously variable transmission 41 (transmission state of the clutch 63). The tension pulley 45 is separated from the transmission belt 44 by the linkage shaft 60, so that the power of the output pulley 29a of the engine 29 is not transmitted to the input pulley 41a of the continuously variable transmission 41 (disconnected state of the clutch 63).

[0085] A sector-shaped linking member 64 is connected to the end of the support shaft 46, and the support shaft 46, the relay member 47 and the linking member 64 are supported so as to swing (rotate) integrally around the axis P3. An arc-shaped long hole 64a is opened in the linking member 64. A linking rod 65 is connected to the arm portion 60a of the linking shaft 60, and a pin-shaped operating portion 65a at the rear of the linking rod 65 is inserted into the long hole 64a of the linking member 64. As described above, the low speed linkage 66 including the linkage rod 61 , the linkage shaft 60 , the linkage member 64 , the linkage rod 65 , etc. is provided between the brake pedal 55 and the linkage member 64 .

[0086] (Low speed linkage operating condition) As shown in Figures 3 and 6, when the brake pedal 55 is not depressed, the spring 62 rotates the linkage shaft 60 in the clockwise direction in Figure 6, the tension pulley 45 is pressed against the transmission belt 44, and the clutch 63 is operated in the transmission state.

[0087] When the gear shift lever 31 is operated to the neutral position N1 and the brake pedal 55 is not depressed, the operating portion 65a of the linking rod 65 is located in the center of the elongated hole 64a of the linking member 64. As a result, even if the gear shift lever 31 is operated between the maximum forward speed position FA and the maximum reverse speed position RA when the brake pedal 55 is not depressed, the long hole 64a of the linking member 64 simply moves forward and backward relative to the operating part 65a of the linking rod 65, and operation of the gear shift lever 31 is not restricted.

[0088] When the brake pedal 55 is not depressed and the gear shift lever 31 is operated to the forward direction, the linking member 64 swings clockwise in Figure 6, and the front end of the long hole 64a of the linking member 64 approaches the operating portion 65a of the linking rod 65.

[0089] When the brake pedal 55 is depressed in the above-mentioned state, the connecting shaft 60 rotates counterclockwise in Figure 6, and the tension pulley 45 is separated from the transmission belt 44, thereby operating the clutch 63 into the disengaged state, and the front wheel 1, rear wheel 2, seedling planting device 6, fertilizer application device 7 and ground leveling device 8 stop.

[0090] As a result, the linking rod 65 is pulled toward the linking shaft 60, the operating portion 65a of the linking rod 65 comes into contact with the front end of the long hole 64a of the linking member 64, and together with the operating portion 65a of the linking rod 65, the linking member 64 (the speed change lever 31 and the continuously variable transmission 41) is swung toward the neutral position N1, and the speed change lever 31 and the continuously variable transmission 41 are operated to the neutral position N1.

[0091] Even if the brake pedal 55 is depressed when the gear shift lever 31 is in the neutral position N1 or in the reverse position, the flexibility of the operating portion 65a of the linking rod 65 and the long hole 64a of the linking member 64 prevents the gear shift lever 31 from being operated from the neutral position N1 or from the position operated to the reverse position.

[0092] (Configuration of the operation arm) As shown in FIGS. 1 and 2, an operating arm 53 having an arch shape in a front view is supported by the front part of the support frame 23 and provided at the front of the machine body 3.

[0093] 4 and 5, the operating arm 53 has a main body 53a and right and left bases 53b. The main body 53a is formed by bending a round pipe, and the channel-shaped bases 53b are connected to the lower part of the main body 53a.

[0094] The base 53b of the operating arm 53 is supported on the support frame 23 so as to be able to swing about an axis P4 along the left-right direction, and the operating arm 53 can be changed to a non-use position B1 (see Figures 1 to 4) in which it stands upright at the front of the body 3, and a use position B2 (see Figure 3) in which it extends forward from the front of the body 3.

[0095] A frame 67 for towing the body 3, which is made by bending a round bar material, is connected in the left-right direction to the front part of the support frame 23. When the operating arm 53 is operated to the use position B2, the base part 53b of the operating arm 53 abuts against the frame 67, and the operating arm 53 is stopped in the use position B2.

[0096] 1 to 4, a center mascot 54, an engine stop switch 85, and a work stop switch 86 (corresponding to a stop operation unit) are attached to an upper portion of the main body portion 53a of the operation arm 53. When the engine stop switch 85 is operated, the engine 29 is stopped.

[0097] When the work stop switch 86 is operated, the same state is obtained as when the lifting lever 27 (see Figure 2) is operated to the raised position, the planting clutch and fertilizer clutch are operated to the disengaged state, the seedling planting device 6, the ground leveling device 8 and the fertilizer application device 7 are stopped, and the seedling planting device 6 is raised to the upper limit position of the lifting range of the link mechanism 4, taking priority over the lifting control function.

[0098] (Operation when moving a riding rice transplanter out of a field and across a ridge) When the riding rice transplanter is taken out of the field and over the ridge, the operator riding on the machine body 3 depresses the brake pedal 55 (see Figs. 2 and 3) to apply the brake and disengage the clutch 63 (see Figs. 3 and 6) to stop the machine body 3. As the brake pedal 55 is depressed, the low speed linkage 66 operates the speed change lever 31 (continuously variable transmission 41) to the neutral position N1.

[0099] An operator aboard the machine body 3 applies a lock lever 57 to the brake pedal 55 and brake lever 56, which are in a depressed state (the brakes are applied and the clutch 63 is disengaged), to hold the brake pedal 55 and brake lever 56 in the depressed state, and then dismounts from the machine body 3.

[0100] An operator who has dismounted from the machine body 3 stands in front of the machine body 3 and operates the operating arm 53 (see Figure 3) from the non-use position B1 to the use position B2, releases the lock lever 57 from the brake pedal 55 and the brake lever 56, and operates the brake pedal 55 and the brake lever 56 to their returned positions (the brakes are released and the clutch 63 is in a transmission state).

[0101] The operator operates the speed change lever 31 from the neutral position N1 to the forward high speed side to move the machine body 3 forward, and holds the operating arm 53 in the usage position B2 to change the direction of the machine body 3 while preventing the front of the machine body 3 from lifting up.

[0102] The operator holds the brake lever 56 and operates the brake pedal 55 and the brake lever 56 to a depressed state, thereby operating the brake to a braking state, operating the clutch 63 to a disengaged state, and operating the speed change lever 31 (continuously variable transmission 41) to the neutral position N1. By operating the engine stop switch 85, the engine 29 can be stopped.

[0103] (Planting work when moving a riding rice transplanter out of the field and across the ridges) As described above, when the riding rice transplanter is taken out of the field and over the ridge, if the seedling planting device 6, the ground leveling device 8, and the fertilizer application device 7 are operating, the planting work can be carried out as described below.

[0104] When the planting clutch and fertilizer clutch are operated into the transmission state and the seedling planting device 6, the ground leveling device 8, and the fertilizer application device 7 are operating, when the brake pedal 55 (see Figures 2 and 3) is depressed and the clutch 63 (see Figures 3 and 6) is operated into the disengaged state, not only does the machine body 3 stop, but the seedling planting device 6, the ground leveling device 8, and the fertilizer application device 7 also stop.

[0105] When the operator operates the operating arm 53 (see Figure 3) from the non-use position B1 to the use position B2, releases the lock lever 57 from the brake pedal 55 and the brake lever 56, operates the brake pedal 55 and the brake lever 56 to their return positions (the brakes are released and the clutch 63 is in the transmission position), and operates the speed change lever 31 (continuously variable transmission 41) from the neutral position N1 to the forward high-speed side, the machine body 3 starts moving forward, and the seedling planting device 6, the soil leveling device 8, and the fertilizer application device 7 start operating.

[0106] The operator holds the operating arm 53 in the use position B2, and while operating the seedling planting device 6, the soil leveling device 8, and the fertilizing device 7, moves the machine body 3 from the field to cross the ridge. Even if the machine body 3 climbs up onto the ridge and the front of the machine body 3 rises, the above-mentioned lifting control function maintains the seedling planting device 6 at a set height from the rice field surface, maintains the seedling planting depth at the set depth, and allows the seedling planting device 6 to plant seedlings normally.

[0107] When the seedling planting device 6 reaches the ridge, the operator operates the work stop switch 86, which creates a state equivalent to the lift lever 27 being operated to the raised position. This causes the planting clutch and fertilizer clutch to be disengaged, the seedling planting device 6, the ground leveling device 8, and the fertilizer applicator 7 to be stopped, and the seedling planting device 6 is raised to the upper limit of the lift range of the link mechanism 4, taking priority over the lift control function, thus completing the planting work.

[0108] (Configuration of the speed control unit) 3 and 7, a speed limiting portion 87 is provided across the gear shift lever 31 and the operating arm 53. The speed limiting portion 87 has a limiting portion 88, a wire 89 (corresponding to a linking mechanism), a spring 90 (corresponding to an adapting portion), a first bolt 91 (corresponding to a first adjusting portion), a second bolt 92 (corresponding to a second adjusting portion), a setting portion 93, and the like.

[0109] 7 and 8, the restricting portion 88 is formed by bending a plate material and is supported by the support shaft 26a of the support member 26 so as to be swingable about an axis P1, and a restricting pin 88a is provided on the upper part of the restricting portion 88. A first bolt 91 and a second bolt 92 are attached to the lower part of the restricting portion 88.

[0110] 3 and 5, arm portion 53c is coupled to right base portion 53b of operating arm 53, and one end of wire 89 is connected to arm portion 53c of operating arm 53. As shown in FIGS. 3, 7 and 8, wire 89 is extended to restricting portion 88, and the other end of wire 89 is connected to a lower portion of restricting portion 88 via spring 90. A setting portion 93 having a bifurcated shape in a side view is connected to a base portion of the auxiliary shift lever 32. The setting portion 93 is provided with a first stopper portion 93a and a second stopper portion 93b.

[0111] (Function of the speed control section when the sub-shift lever is in the low-speed position) As described above, when the riding rice transplanter is moved out of the field and over the ridge, when the sub-transmission lever 32 (sub-transmission device 42) is operated to the low-speed position L, as shown in Figures 3 and 9, the first stopper portion 93a of the setting portion 93 is opposed to the first bolt 91.

[0112] When the operating arm 53 is operated from the non-use position B1 to the use position B2 with the sub-speed change lever 32 (sub-speed change device 42) operated to the low-speed position L, the wire 89 is pulled toward the operating arm 53, and the restricting portion 88 is swung clockwise in Fig. 9. The first bolt 91 comes into contact with the first stopper portion 93a of the setting portion 93, so that the position of the restricting portion 88 is determined, and the restricting pin 88a of the restricting portion 88 is positioned at the first low-speed position FL1 (corresponding to a first state in which the restricting portion 88 is positioned at a position corresponding to the first low-speed position FL1).

[0113] In this case, the amount of movement of the lower part of the restricting portion 88 is set to be slightly smaller than the operating stroke of the wire 89 when the operating arm 53 is operated from the non-use position B1 to the use position B2.

[0114] As a result, when the operating arm 53 is operated to the use position B2 and the first bolt 91 hits the first stopper portion 93a of the setting portion 93, the spring 90 is slightly extended, absorbing the difference between the operating stroke of the wire 89 and the amount of movement of the lower part of the restricting portion 88. Since the spring 90 is slightly extended, a compressive biasing force of the spring 90 is generated (the compressive biasing force of the spring 90 becomes large), the restricting portion 88 is stably held in the first low speed position FL1.

[0115] By rotating the first bolt 91 to change the position of the first bolt 91 in the restricting portion 88, it is possible to adjust the attitude of the restricting portion 88 when the first bolt 91 hits the first stopper portion 93a of the setting portion 93. This makes it possible to adjust the position of the first low speed position FL1 where the restricting pin 88a of the restricting portion 88 is located to a higher or lower position.

[0116] In the above-mentioned state, when the shift lever 31 (continuously variable transmission 41) is operated from the neutral position N1 toward the forward higher speed side, when the receiving portion 37d of the shift lever 31 (transmission member 37) hits the regulating pin 88a (first low speed position FL1) of the regulating portion 88, operation of the shift lever 31 (continuously variable transmission 41) toward the forward higher speed side beyond the first low speed position FL1 is regulated by the regulating portion 88.

[0117] (Function of the speed control section when the sub-shift lever is in the high-speed position) As mentioned above, when the riding rice transplanter is moved out of the field and over the ridge, when the sub-transmission lever 32 (sub-transmission device 42) is operated to the high speed position H, as shown in Figures 3 and 10, the second stopper portion 93b of the setting portion 93 is opposed to the second bolt 92.

[0118] When the operating arm 53 is operated from the non-use position B1 to the use position B2 with the sub-speed change lever 32 (sub-speed change device 42) operated to the high speed position H, the wire 89 is pulled toward the operating arm 53, and the restricting portion 88 is swung clockwise in Fig. 10. The second bolt 92 comes into contact with the second stopper portion 93b of the setting portion 93, so that the position of the restricting portion 88 is determined, and the restricting pin 88a of the restricting portion 88 is positioned at the second low speed position FL2 (corresponding to a second state in which the restricting portion 88 is positioned at a position corresponding to the second low speed position FL2).

[0119] In this case, the second low speed position FL2 is set to a lower speed than the first low speed position FL1 (see FIG. 9). Since the second low speed position FL2 is set to a lower speed than the first low speed position FL1, the amount of movement of the lower part of the restricting portion 88 with respect to the operating stroke of the wire 89 when the operating arm 53 is operated from the non-use position B1 to the use position B2 is smaller than the amount of movement of the restricting portion 88 when the restricting portion 88 is operated to a position corresponding to the first low speed position FL1 (first state).

[0120] As a result, when the operating arm 53 is operated to the use position B2 and the second bolt 92 hits the second stopper portion 93b of the setting portion 93, the spring 90 is slightly extended, absorbing the difference between the operating stroke of the wire 89 and the amount of movement of the lower part of the restricting portion 88. Since the spring 90 is slightly extended, a compressive biasing force of the spring 90 is generated (the compressive biasing force of the spring 90 becomes large), the restricting portion 88 is stably held in the second low speed position FL2.

[0121] Even if the position of the restricting portion 88 at the first low speed position FL1 differs from the position of the restricting portion 88 at the second low speed position FL2, this position difference is absorbed by the spring 90 provided on the wire 89.

[0122] By rotating the second bolt 92 to change the position of the second bolt 92 in the restricting portion 88, it is possible to adjust the attitude of the restricting portion 88 when the second bolt 92 hits the second stopper portion 93b of the setting portion 93. This makes it possible to adjust the position of the second low speed position FL2 where the restricting pin 88a of the restricting portion 88 is located to a higher or lower position.

[0123] In the above-mentioned state, when the shift lever 31 (continuously variable transmission 41) is operated from the neutral position N1 toward the forward higher speed side, when the receiving portion 37d of the shift lever 31 (transmission member 37) hits the regulating pin 88a (second low speed position FL2) of the regulating portion 88, operation of the shift lever 31 (continuously variable transmission 41) toward the forward higher speed side beyond the second low speed position FL2 is regulated by the regulating portion 88.

[0124] Because the second low speed position FL2 is set to a lower speed than the first low speed position FL1, the difference in the running speed of the machine 3 is small between the running speed of the machine 3 when the sub-transmission device 42 is operated to the low speed position L and the shift lever 31 (continuously variable transmission device 41) is operated to the first low speed position FL1, and the running speed of the machine 3 when the sub-transmission device 42 is operated to the high speed position H and the shift lever 31 (continuously variable transmission device 41) is operated to the second low speed position FL2.

[0125] (Speed ​​limiter status) The state shown in Figure 9 is a state in which, when the operating arm 53 is operated to the usage position B2 with the sub-transmission device 42 (second transmission device) operated to the low speed side, the operation of the continuously variable transmission device 41 (first transmission device) to the high speed side is restricted by the speed restriction unit 87 to the first low speed position FL1. This is a state in which speed restriction portion 87 restricts operation of gear shift lever 31 (first gear shift operating device) to the first low-speed position FL1. This is a state in which speed restriction unit 87 restricts operation of continuously variable transmission 41 (first transmission) to the high speed side at first low speed position FL1 based on the operational position of sub-transmission lever 32 (second transmission).

[0126] 10 is a state in which, when the operating arm 53 is operated to the use position B2 with the sub-transmission device 42 (second transmission device) operated to the high-speed side, operation of the continuously variable transmission device 41 (first transmission device) to the high-speed side is restricted at the second low-speed position FL2 by the speed restriction unit 87. The second low-speed position FL2 is set to a speed lower than the first low-speed position FL1 (see FIG. 9). This is a state in which speed restriction section 87 restricts operation of gear shift lever 31 (first gear shift operating device) to the second low-speed position FL2. This is a state in which speed restriction unit 87 restricts operation of continuously variable transmission 41 (first transmission) to the high speed side at second low speed position FL2, based on the operational position of sub-transmission lever 32 (second transmission).

[0127] As shown in FIGS. 3, 9 and 10, the speed restricting section 87 is provided with a restricting section 88 that is capable of restricting operation of the continuously variable transmission 41 (first transmission) to the high-speed side. A wire 89 (linkage mechanism) is provided which is connected between the operating arm 53 and the regulating portion 88 and which, when the operating arm 53 is operated to the usage position B2, moves the regulating portion 88 toward a position where operation of the continuously variable transmission 41 (first transmission) to the high speed side can be regulated. A spring 90 (accommodating portion) is provided on the wire 89 (linking mechanism). A setting unit 93 is provided which sets the regulating unit 88 to a first state in which it is positioned at a position corresponding to the first low speed position FL1, and a second state in which it is positioned at a position corresponding to the second low speed position FL2, based on the operating position of the sub-transmission device 42 (second transmission device).

[0128] (Linkage structure between the operating arm and the steering member of the front wheels) As shown in Figures 3, 4, and 5, a retaining portion 68 formed by bending a round bar material is supported by a bracket 23a of the support frame 23 and a bracket 69 connected to the transmission case 22 so as to be swingable around an axis P7 along the left-right direction.

[0129] A pin 53d is connected to the upper part of the right base portion 53b of the operating arm 53, and a linking member 70 having an angle shape in a plan view is connected to the pin 53d of the operating arm 53 so as to be able to swing up and down.

[0130] A linking rod 71 is provided, and a front portion of the linking rod 71 is inserted into an opening (not shown) of the linking member 70 so as to be movable in the front-rear direction, and a spring 72 is attached between the linking member 70 and the front portion of the linking rod 71. A rear portion of the linking rod 71 is connected to the arm portion 68b of the holding portion 68.

[0131] (Configuration of the front wheel differential lock mechanism and the linkage structure between the operating arm and the front wheel differential lock mechanism) As shown in Figures 3, 4, and 5, a differential lock mechanism 74 that can operate the front wheel differential mechanism 50 into a differential lock state is provided inside the transmission case 22, and an axial differential lock section 75 that operates the differential lock mechanism 74 is provided so as to protrude rearward from the rear face of the transmission case 22.

[0132] The differential lock unit 75 is supported by the transmission case 22 so as to be rotatable about an axis P8 along the front-rear direction, and an operation unit 76 is connected to the rear of the differential lock unit 75. A spring (not shown) inside the transmission case 22 biases the differential lock mechanism 74 and the differential lock unit 75 to the release position.

[0133] A differential lock pedal 77 is provided, and a body 77a of the differential lock pedal 77 is supported so as to be vertically movable on a support member 78 connected to the transmission case 22. The lower part of the body 77a of the differential lock pedal 77 is inserted into an elongated hole (not shown) of the operating part 76, and a step part 77b of the differential lock pedal 77 protrudes upward from the floor 28. A spring 79 that biases the differential lock pedal 77 upward (to the release position) is attached between the body 77a of the differential lock pedal 77 and the support member 78.

[0134] 3 and 4 show a state in which the differential lock unit 75, the operating unit 76, and the differential lock pedal 77 are operated to the release position by a spring (not shown) inside the transmission case 22 and a spring 79. When the differential lock pedal 77 is depressed, the differential lock unit 75 and the operating unit 76 are operated to the differential lock position, and the front wheel differential mechanism 50 is operated to the differential lock state.

[0135] A linking rod 80 is provided, and a front portion of the linking rod 80 is connected to the arm portion 68b of the holding portion 68. A relay member 81 is supported at the upper right portion of the transmission case 22 so as to be swingable about an axis P9 along the left-right direction, and a rear portion of the linking rod 80 is connected to the relay member 81 via a spring 83. A linking rod 84 is connected between the relay member 81 and an elongated hole (not shown) of the operating portion 76.

[0136] (State of the front wheel steering member and front wheel differential mechanism when the operating arm is operated to the use position) The state shown in Figures 3, 4, and 5 is a state in which the operating arm 53 is operated to the non-use position B1, the operating portion 68a of the holding portion 68 is moved forward away from the steering member 36, allowing steering of the front wheels 1, and the differential lock portion 75 and the operating portion 76 are operated to the released position, causing the front wheel differential mechanism 50 to operate.

[0137] As described above, when moving the riding rice transplanter out of the field and over the ridge, before operating the operating arm 53 to the use position B2, the operator operates the steering handle 25 to operate the front wheels 1 to a straight-ahead position and positions the recess 36a provided in the steering member 36 behind the operating portion 68a of the holding portion 68.

[0138] When the operating arm 53 is operated to the usage position B2 from the state shown in Figures 4 and 5, the linking member 70 and the linking rod 71 are pulled toward the operating arm 53, the holding portion 68 is rotated clockwise in Figure 4, the operating portion 68a of the holding portion 68 enters the recess 36a of the steering member 36, and the steering member 36 (front wheel 1) is held in a straight-ahead position.

[0139] When the holding portion 68 (arm portion 68b) is rotated clockwise in FIG. 4, the linking rod 80 is pulled toward the holding portion 68 (operation arm 53). When the linking rod 80 is pulled toward the holding portion 68 (the operating arm 53), the relay member 81 is swung counterclockwise in Figure 4, and the linking rod 84 is operated downward, so that the differential lock portion 75 and the operating portion 76 are operated to the differential lock position, and the front wheel differential mechanism 50 is operated to the differential lock state.

[0140] As described above, when the operating arm 53 is operated from the non-use position B1 to the use position B2, as described above, the speed restriction unit 87 restricts operation of the shift lever 31 (continuously variable transmission 41) beyond the first low-speed position FL1 (second low-speed position FL2) toward the higher forward speed side, and in addition, the steering member 36 (front wheels 1) is held in a straight-ahead position and the front wheel differential mechanism 50 is operated to a differential lock state.

[0141] (First Alternative Embodiment of the Invention) In the low speed linkage unit 66, when the brake pedal 55 and the brake lever 56 are operated to a depressed state, the shift lever 31 and the continuously variable transmission 41 may be configured to be operated to a third low speed position lower than the first low speed position FL1 and the second low speed position FL2, rather than to the neutral position N1.

[0142] According to the above-described configuration, when the brake pedal 55 and the brake lever 56 are operated to a depressed state (the brakes are applied and the clutch 63 is disengaged) and then to a released state (the brakes are released and the clutch 63 is engaged), the machine body 3 begins to move forward at a sufficiently low speed due to the third low speed position of the continuously variable transmission 41.

[0143] (Second Alternative Embodiment of the Invention) In the low speed linkage section 66, the linkage member 64 and the linkage rod 65 may be eliminated, and when the brake pedal 55 and the brake lever 56 are operated to a depressed operation state, the clutch 63 is operated to a disengaged state, and the speed change lever 31 (continuously variable transmission 41) is left in the current operating position.

[0144] According to the above-described configuration, when the brake pedal 55 and the brake lever 56 are operated to a depressed state (the brakes are applied and the clutch 63 is disengaged) and held by the lock lever 57, and then the operating arm 53 is operated from the non-use position B1 to the use position B2, in the speed restriction unit 87, the restriction unit 88 is operated to swing clockwise in Figures 9 and 10, and the restriction pin 88a of the restriction unit 88 pushes the receiving portion 37d of the shift lever 31 (shift member 37) to the right in Figures 9 and 10, thereby decelerating the shift lever 31 (continuously variable transmission 41) to the low speed side.

[0145] In this case, when the sub-transmission lever 32 (sub-transmission device 42) is operated to the low-speed position L, as shown in FIG. 9, the first bolt 91 comes into contact with the first stopper portion 93a of the setting portion 93, causing the regulating portion 88 to stop at the first low-speed position FL1, and the transmission lever 31 (continuously variable transmission device 41) is operated to decelerate to the first low-speed position FL1.

[0146] When the sub-speed change lever 32 (sub-transmission device 42) is operated to the high speed position H, as shown in FIG. 10, the second bolt 92 hits the second stopper portion 93b of the setting portion 93, causing the regulating portion 88 to stop at the second low speed position FL2, and the speed change lever 31 (continuously variable transmission device 41) is operated to decelerate to the second low speed position FL2.

[0147] Thereafter, the operator releases the lock lever 57 from the brake pedal 55 and the brake lever 56, and operates the brake pedal 55 and the brake lever 56 to their return states (brake release state and clutch 63 transmission state). As a result, the machine body 3 starts moving forward at a low speed due to the first low speed position FL1 (second low speed position FL2) of the continuously variable transmission 41.

[0148] (Third Alternative Embodiment of the Invention) In the above-mentioned (second alternative embodiment of the invention), a seating sensor (not shown) that detects whether or not an operator is seated in the driver's seat 20, a locking mechanism (not shown) that can fix the lock lever 57, and an arm sensor (not shown) that detects that the operating arm 53 has been operated to the usage position B2 may be provided and configured as described below.

[0149] When the brake pedal 55 and the brake lever 56 are operated to a stepped-on state (the brakes are applied and the clutch 63 is disengaged) and held by the lock lever 57, the lock mechanism fixes the lock lever 57 in the held state when the seat sensor detects that the operator has dismounted from the machine body 3.

[0150] Next, even if an operator who has got off the machine body 3 attempts to remove the lock lever 57 from the brake pedal 55 and the brake lever 56, the lock lever 57 is fixed in a retaining state by the lock mechanism, so the operator cannot operate the lock lever 57.

[0151] Before releasing the lock lever 57 from the brake pedal 55 and the brake lever 56, the operator operates the operating arm 53 to the usage position B2 so that the shift lever 31 (continuously variable transmission 41) is decelerated to the first low-speed position FL1 (second low-speed position FL2) as described above (second alternative embodiment of the invention).

[0152] When the arm sensor detects that the operating arm 53 has been operated to the usage position B2, the locking mechanism is released, allowing the operator to remove the lock lever 57 from the brake pedal 55 and the brake lever 56, and operate the brake pedal 55 and the brake lever 56 to their returned states (brake release state and clutch 63 transmission state).

[0153] (Fourth Alternative Embodiment of the Invention) In the configurations shown in Figures 1 to 10 described above, and in the (first alternative embodiment of the invention), (second alternative embodiment of the invention), and (third alternative embodiment of the invention), a brake linkage unit (not shown) may be provided that automatically releases the lock lever 57 from the brake pedal 55 and the brake lever 56 (operates the brake holding unit to a release state) when the operating arm 53 is operated to the use position B2.

[0154] (Fifth Alternative Embodiment of the Invention) When the sub-transmission device 42 is configured to be capable of changing speeds in three or more stages, it may be configured as described below. When the sub-transmission device 42 is operated to the lowest speed position, a first low speed position FL1 is set by the speed restriction unit 87. When the sub-transmission device 42 is operated to a speed change position other than the lowest speed position, a plurality of second low speed positions FL2 that are slightly different from each other are set in accordance with the speed change positions of the sub-transmission device 42.

[0155] (Sixth Alternative Embodiment of the Invention) A belt-type continuously variable transmission (not shown) may be provided as the first transmission instead of the hydrostatic type continuously variable transmission 41. In this configuration, the sub-transmission 42 may be configured to be capable of changing the speed between multiple forward speeds and one reverse speed.

[0156] (Seventh Alternative Embodiment of the Invention) In the speed regulating section 87, instead of the wire 89, a plurality of connecting rods (not shown) and relay links (not shown) may be connected between the operating arm 53 and the regulating section 88 as a linking mechanism, and a flexible section may be provided in the intermediate portion between the operating arm 53 and the regulating section 88 in the linking mechanism.

[0157] (Eighth Alternative Embodiment of the Invention) In the speed regulation unit 87, the regulation unit 88 and the wire 89 may be eliminated, and an arm sensor (not shown) that detects when the operating arm 53 is operated to the use position B2, and an electric actuator (not shown) may be provided. Since mud from the rice field surface tends to adhere to the arm sensor, a mud cover (not shown) may be provided on the arm sensor.

[0158] According to this configuration, when the operating arm 53 is operated to the usage position B2, the electric actuator can be configured to set the first low speed position FL1 and the second low speed position FL2 for the shift lever 31 based on detection by the arm sensor, and the electric actuator can be configured to decelerate the shift lever 31 to the first low speed position FL1 and the second low speed position FL2.

[0159] In this case, the electric actuator may be configured to directly set the first low speed position FL1 and the second low speed position FL2 for the continuously variable transmission 41, or the electric actuator may be configured to directly decelerate the continuously variable transmission 41 to the first low speed position FL1 and the second low speed position FL2.

[0160] (Ninth Alternative Embodiment of the Invention) A speed sensor (not shown) may be provided that detects the number of revolutions of the front wheel 1 or the rear wheel 2 to detect the traveling speed of the machine body 3, and may be configured as described below. When the riding rice transplanter is taken out of the field over the ridge, if the running speed of the machine body 3 exceeds a preset low speed value with the operating arm 53 operated to the use position B2, the engine 29 is automatically stopped and the continuously variable transmission 41 is automatically operated to the neutral position N1.

[0161] (Tenth Alternative Embodiment of the Invention) When the riding rice transplanter is taken out of the field over the ridge, when the positioning unit 21 detects that the seedling planting device 6 has reached the ridge, the lift lever 27 may be automatically set to the raised position to obtain the same state. This allows the planting work to be automatically completed.

[0162] (Eleventh Alternative Embodiment of the Invention) In the configuration shown in FIGS. 9 and 10, the second bolt 92 may be configured to protrude from the restricting portion 88 toward the setting portion 93 more than the first bolt 91. According to this configuration, when the sub-transmission lever 32 (sub-transmission device 42) is operated to the high speed position H and the operating arm 53 is operated from the non-use position B1 to the use position B2, the second bolt 92 immediately hits the second stopper portion 93b of the setting portion 93. As a result, the second low-speed position FL2 (see Figure 10) where the regulating pin 88a of the regulating portion 88 is located is faster than the first low-speed position FL1 (see Figure 9) where the regulating pin 88a of the regulating portion 88 is located due to the first bolt 91 hitting the first stopper portion 93a of the setting portion 93. [Industrial Applicability]

[0163] The present invention can be applied not only to riding rice transplanters, but also to paddy field working machines such as riding direct seeders in which a sowing device (not shown) (corresponding to a working device) that supplies seed rice to the rice field surface is supported by a link mechanism 4, and riding pesticide sprayers in which a pesticide spraying device (not shown) (corresponding to a working device) that sprays pesticides on the rice field surface is supported by a link mechanism 4. [Explanation of symbols]

[0164] 3. Aircraft 4 Link mechanism (lifting mechanism) 5 Hydraulic cylinder (lifting mechanism) 6 Seedling planting device (work device) 7 Fertilizer application equipment (work equipment) 8 Ground leveling equipment (work equipment) 31 Gear shift lever (first gear shift operating device) 32 Sub-shift lever (second shift operating device) 41 Continuously variable transmission (first transmission) 42 Auxiliary transmission (second transmission) 53 Operating Arm 55 Brake pedal (brake operation device) 56 Brake lever (brake operating device) 57 Lock lever (brake retainer) 66 Low-speed linkage 86 Work stop switch (stop operation part) 87 Speed ​​regulation section 88 Regulatory Department 89 Wire (linking mechanism) 90 Spring (flexible part) 91 First bolt (first adjustment part) 92 Second bolt (second adjustment part) 93 Setting section B1 Non-use position B2 Usage posture FL1 1st low speed position FL2 2nd low speed position N1 Neutral position (stop position)

Claims

1. A first transmission for traveling; A second transmission for traveling; an operating arm provided at a front portion of the body so as to be capable of changing its position between a non-use position in which the operating arm stands up at a front portion of the body and a use position in which the operating arm extends forward from the front portion of the body; a speed restriction unit that restricts operation of the first transmission to a high speed side at a first low speed position when the operating arm is operated to the use position with the second transmission operated to a low speed side, and restricts operation of the first transmission to a high speed side at a second low speed position when the operating arm is operated to the use position with the second transmission operated to a high speed side, A paddy field working machine, wherein the first low speed position and the second low speed position are speed positions different from each other.

2. The paddy field working machine according to claim 1, wherein the second low speed position is set to a speed slower than the first low speed position.

3. a first gear shift operating tool capable of manually operating the first gear shift device is provided; The paddy field working machine according to claim 1 , wherein the speed restricting section restricts operation of the first speed change operating device to a higher speed side at the first low speed position and the second low speed position.

4. a second gear shift operating device capable of manually operating the second gear shift device is provided; The paddy field working machine according to claim 1 , wherein the speed regulating unit regulates operation of the first transmission device to the high speed side at the first low speed position and the second low speed position based on the operating position of the second transmission operating tool.

5. 2. The paddy field working machine according to claim 1, further comprising a first adjustment section capable of adjusting the first low speed position to a high or low position, and a second adjustment section capable of adjusting the second low speed position to a high or low position.

6. The paddy field working machine according to claim 1, wherein a stop operation unit capable of stopping the working device supported on the machine body is provided on the operating arm.

7. a lifting mechanism that supports the working device on the machine body so that the working device can be raised and lowered; The paddy field working machine according to claim 6, wherein the lifting mechanism lifts the working implement to an upper limit position of a lifting range when the stop operating part is operated.

8. The speed regulation unit is a restricting portion that restricts operation of the first transmission device to a higher speed; a linkage mechanism that is connected between the operating arm and the regulating portion, and that moves the regulating portion toward a position where operation of the first transmission device to a higher speed side can be restricted as the operating arm is operated to the use position; A flexible unit provided in the linkage mechanism; 2. The paddy field working machine according to claim 1, further comprising a setting unit that sets the regulating unit to a first state in which the regulating unit is positioned at a position corresponding to the first low speed position, and a second state in which the regulating unit is positioned at a position corresponding to the second low speed position, based on the operating position of the second transmission device.

9. Driving brakes and A brake operating tool capable of manually operating the brake; The paddy field working machine according to claim 1, further comprising a low speed linkage unit which operates the first transmission device to a stop position or a third low speed position which is slower than the first low speed position and the second low speed position when the brake is operated into a braking state by the brake operating device.

10. Driving brakes and a brake holding unit operable to hold the brake in a holding state and to release the holding state; The paddy field working machine according to claim 1, further comprising a brake linkage section which operates the brake holding section to the holding release state when the operating arm is operated to the use position.

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