JP3346918B2 - Work vehicle ground work equipment lifting structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ascending / descending structure of a ground working device in a work vehicle in which a ground working device is connected to a rear portion of an airframe by an actuator so as to be able to move vertically.

[0002]

2. Description of the Related Art As an example of the work vehicle described above, there is a riding type rice transplanter in which a seedling planting device (corresponding to a ground working device) is connected to the rear of the body so as to be able to move up and down freely. In such a riding type rice transplanter, when a shift lever (equivalent to a shift operation tool) of a traveling transmission is operated to the reverse side, as disclosed in, for example, Japanese Patent Application Laid-Open No. 3-83503, an actuator is used to set seedlings. Some planting devices are configured to be automatically raised. This prevents the grounding body such as the float of the seedling planting device from being damaged by moving the body backward while the seedling planting device is in contact with the rice field (the ground).

[0003] In this case, if the start of backward movement of the airframe and the start of ascent of the seedling planting device are substantially the same, at the start of the backward movement of the aircraft, there is a state in which the airplane moves backward with the grounding member of the seedling planting device grounded. Occurs temporarily. Therefore, utilizing the point that the ground contact body such as a float is supported on the seedling planting apparatus so as to be able to move up and down within a set range, when the shift lever is operated to the reverse side, first, the raising operation of the seedling planting apparatus is performed. When the ground contact body of the seedling planting device is lowered to the lower limit of the set range, it is determined that the seedling planting device has been completely lifted from the rice field, and the reverse is started by the transmission for traveling. There are those that have been configured.

[0004]

SUMMARY OF THE INVENTION In a riding type rice transplanter having the above-described structure, for example, soil or the like is caught in a portion that supports a floating body such as a float in a seedling planting apparatus so as to be able to move up and down. Assume that the grounding member does not drop to the lower limit of the setting range. When the operator operates the shift lever in the reverse direction in such a state, even if the seedling planting device is completely raised from the rice field as described above, the grounding body of the seedling planting device is set at the lower limit of the set range. The vehicle does not descend and does not start reverse.

[0005] If the body does not move backward while the seedling planting apparatus is being lifted as described above, the operator may have an abnormality (a state in which the grounding body does not fall to the lower limit of the set range due to biting of soil or the like). There is a case where the operator performs an operation of getting down from the control section of the aircraft and artificially lowering the ground contact body to the lower limit of the set range. When such an operation is performed, the aircraft starts reversing, and the operator who gets off the aircraft needs to quickly get on the control section of the aircraft, but if the operator misses the aircraft, the aircraft moves backward and the rear ridge And so on. According to the present invention, in an ascending / descending structure for a ground work device of a work vehicle configured such that the ground work device is automatically raised when the vehicle moves backward as described above, the airframe moves backward and collides with an obstacle such as a ridge. The purpose is to prevent such situations.

[0006]

A feature of the present invention resides in the following structure of the above-described structure for elevating and lowering the ground working device of the working vehicle. That is, [1] a ground work device is connected to the rear part of the body by an actuator so as to be able to move up and down by an actuator, and a grounding body that is in contact with the ground is provided in the ground work device so as to be able to move up and down within a set range. When the speed change operation tool for shifting the gear is operated to the reverse side, it is provided with a forced ascending means for operating the actuator to the ascending side, and until a set time elapses from the start of the ascent operation of the ground work device by the forced ascending means. To
When the grounding body reaches the lower limit of the set range, the reverse of the body by the traveling transmission is allowed, and even if the set time has elapsed from the start of the ascent operation of the ground work device by the forced ascending means,
If the grounding body does not reach the lower limit of the set range, the vehicle is provided with reverse control means for preventing the vehicle from moving backward by the traveling transmission.

[2] A ground working device is connected to a rear portion of the body by an actuator so as to be able to move up and down by an actuator, and a grounding body that is in contact with the ground is provided in the ground working device so as to be able to move up and down within a set range.
When the shift operation device for artificially shifting the speed of the traveling transmission is operated to the reverse side, the vehicle is provided with a forced ascending means for operating the actuator to the ascending side. When the grounding body reaches the lower limit of the setting range at a speed lower than the set speed, the vehicle is allowed to move backward by the transmission for traveling, and the grounding body is moved below the set speed with the rise of the ground work device by the forced ascending means. When the vehicle reaches the lower limit of the set range at a high speed, the vehicle is provided with reverse control means for preventing the vehicle from moving backward by the traveling transmission.

[3] A ground work device is connected to the rear of the body by an actuator so as to be able to move up and down by an actuator, and a pair of right and left grounding members that contact the ground are provided in the ground work device so as to be able to move up and down within a set range. When the shift operation device that artificially shifts the device is operated to the reverse side, it is provided with a forced ascending means for operating the actuator to the ascending side. When both of the bodies reach the lower limit of the setting range at substantially the same time, the vehicle is allowed to move backward by the transmission for traveling, and both or one of the grounding bodies is set even if the ground work device is raised by the forced ascending means. If the lower limit is not reached, the vehicle is provided with reverse control means for preventing the vehicle from moving backward by the traveling transmission.

[0009]

[Action]

[I] With the configuration as described in [1] above, when the shift operation tool is operated to the reverse side, for example, as shown in FIG. 1, the ground work device 6 starts to be automatically raised by the actuator 5. In this case, if the grounding body 13 of the ground work device 6 reaches the lower limit of the set range before the set time elapses after the ground work device 6 starts being raised, the grounding device 13 is brought into contact with the ground operation device 6 in accordance with the lift operation. Since the body 13 is in a lowered state, it is determined that the ground working device 6 has been completely lifted from the ground G, and it is determined that the ground working device 6 is in a normal state. .

Conversely, if the grounding body 13 does not reach the lower limit of the set range even if the set time elapses after the ground work device 6 starts to be lifted, soil or the like is caught in the support portion of the grounding body 13. Since it can be determined that the grounding body 13 has not descended to the lower limit of the set range, the aircraft does not move backward in such a case. In such a state, the operator operates the control unit 3
Go down to the ground working device 6 side, remove the soil etc. bitten by the support part of the grounding body 13, and perform the operation of lowering the grounding body 13 artificially to the lower limit of the set range. Sometimes. In this case, the grounding body 13 reaches the lower limit of the setting range. However, since this is not performed until the set time has elapsed, the operator manually sets the grounding body 13 as described above. The aircraft does not move backwards even when descending to the lower end of the range.

[II] With the configuration as described in the preceding paragraph [2], when the speed change operation tool is operated to the reverse side, for example, as shown in FIG. 1, the ground work device 6 starts to be automatically raised by the actuator 5. In this case, the grounding body 13 descends to the lower limit of the set range in accordance with the ascent operation of the ground work device 6, but when the grounding body 13 slowly descends at a speed lower than the set speed and reaches the lower limit. It is determined that the grounding body 13 has slowly and slowly dropped to the lower limit of the set range due to its own weight or the like. As a result, it is determined that the ground working device 6 has been completely lifted from the ground G, and it is determined that the ground working device 6 is in a normal state, and the traveling transmission is allowed to move backward, and the aircraft starts to move backward.

Conversely, even if the ground work apparatus 6 starts to be lifted, the aircraft does not move backward unless the grounding body 13 reaches the lower limit of the set range, so that soil or the like is caught in the support portion of the grounding body 13, It can be determined that the grounding body 13 has not fallen to the lower limit of the set range. In such a case, the operator descends from the control unit 3 and goes to the ground work device 6 side, and
In some cases, an operation such as removing the soil or the like caught in the supporting portion 3 and lowering the grounding body 13 artificially to the lower limit of the set range may be performed. In this case, when the operator artificially operates the grounding body 13 to the lower limit of the set range, generally, the grounding body 13 is quickly operated to the lower limit. Thus, when the grounding body 13 reaches the lower limit of the setting range at a speed higher than the set speed, it can be determined that the operator has artificially operated the grounding body 13 to the lower limit of the setting range. In such a case, The aircraft does not reverse.

[III] With the construction as described in the above item [3], when the shift operation tool is operated to the reverse side, for example, as shown in FIG. 1, the ground work device 6 starts to be automatically raised by the actuator 5. In this case, when the right and left grounding bodies 21 descend almost simultaneously to the lower limit of the set range in accordance with the ascending operation of the ground work device 6, it is determined that the ground work device 6 has been completely lifted from the ground G, and a normal state is established. When it is determined that there is, the reverse is allowed by the traveling transmission, and the aircraft starts to reverse.

Conversely, even if the ground work device 6 starts to be lifted, the aircraft does not move backward unless the left and right grounding bodies 21 reach the lower limit of the set range at substantially the same time. The left and right or both grounding bodies 2
It can be determined that 1 has stopped falling to the lower limit of the setting range. In such a case, the worker descends from the control section 3 and goes to the ground working device 6 side, removes soil or the like bitten by the support portion of the grounding body 21, and removes both the left and right or one of the grounding bodies 21 An operation of artificially lowering the lower limit of the setting range may be performed. When the worker artificially lowers the left and right grounding bodies 21, the left and right grounding bodies 21 are separated from each other. One grounding body 21
Is lowered, and then the other grounding body 21 is lowered. Accordingly, if the left and right grounding bodies 21 do not reach the lower limit of the set range substantially simultaneously when the ground working device 6 starts to be lifted, even if the left and right grounding bodies 21 subsequently reach the lower limit of the set range, Can determine that the operator has artificially operated the left and right grounding bodies 21 to the lower limit of the set range. In such a case, the aircraft does not move backward.

[0015]

According to the first, second and third aspects of the present invention,
When the shift operation tool is operated in the reverse direction, the ground work device is automatically lifted when the ground work device is lifted up and down. When the body does not descend, even if the grounding body descends thereafter, it is possible to accurately recognize that this is manually performed by the operator. With this, even if the operator gets off the control section and artificially lowers the grounding body to the lower limit of the setting range, the aircraft can be configured not to move backward, and the operator can not move backward and It was possible to prevent a situation in which the vehicle hits a rear ridge or the like beforehand, thereby improving the workability of the work vehicle.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a control unit 3 is formed on a body supported by a front wheel 1 and a rear wheel 2, and a link mechanism 4 is provided on a rear part of the body.
A hydraulic cylinder 5 (corresponding to an actuator) for driving the link mechanism 4 up and down, and a seedling planting device 6 (corresponding to a ground working device) connected to a rear portion of the link mechanism 4; Is a riding type rice transplanter which is an example of the above.

As shown in FIGS. 2 and 1, a control valve 7 for supplying and discharging hydraulic oil to and from the hydraulic cylinder 5 to operate the hydraulic cylinder 5, a planting clutch 8 for transmitting power to the seedling planting device 6, and A motor 9 for transmitting and cutting off the planting clutch 8
Is provided. Hydraulic cylinder 5 and planting clutch 8
Is provided on the control unit 3 of the aircraft,
The operation position of the operation lever 10 is input to the control device 11.

When the operating lever 10 is moved to a raised position, a neutral position and a lowered position along the lever guide 12 shown in FIG. 3, the control valve 7 is operated in a state where the planting clutch 8 is operated by the motor 9 to cut off the transmission. The hydraulic cylinder 5 operates the raising, stopping, and lowering operations of the seedling plant 6 by operating the supply position, the neutral position, and the discharge position of the hydraulic oil. When the operating lever 10 is operated to the planting position of the lever guide 12, the planting clutch 8 is operated to the transmission side by the motor 9, and the seedling planting device 6 is maintained at the set height from the rice field G (corresponding to the ground). As described above, the control valve 7 is operated, the hydraulic cylinder 5 is operated to expand and contract, and the seedling planting device 6 is automatically moved up and down, which is a normal planting state.

As shown in FIG. 2 and FIG.
Float 13 around the horizontal axis P1
(Corresponding to a grounding body) is supported by a mechanical stopper or the like so as to be able to move up and down within a set range, and is provided with a potentiometer 14 for detecting the vertical angle of the sensor float 13 with respect to the seedling planting device 6. Thus, at the planting position of the operating lever 10, the height of the seedling planting device 6 with respect to the sensor float 13 following the ground surface G is detected as the vertical angle of the sensor float 13 by the potentiometer 14 and input to the control device 11. Then, the control valve 7 is operated by the control device 11 based on the detection value of the potentiometer 14.

As shown in FIG. 2, in this riding type rice transplanter,
A hydrostatic continuously variable transmission 15 (corresponding to a transmission for traveling) is provided for traveling. Hydrostatic continuously variable transmission 1
Reference numeral 5 denotes an electric cylinder 16 which is capable of steplessly changing the speed of the hydrostatic type continuously variable transmission 15 on the forward side F and the reverse side R with the neutral stop position N interposed therebetween. Potentiometer 17 for detecting the extension position
Is provided.

A shift lever 19 (corresponding to a shift operation tool) operable on the forward side F and the reverse side R across the neutral stop position N as shown in FIG. 2 is provided on the right side of the steering handle 18 shown in FIG. The operation position of the shift lever 19 and the detection value of the potentiometer 17 are input to the control device 11. As a result, the hydrostatic stepless transmission 15 is operated by the control device 11 and the electric cylinder 16 so that when the shift lever 19 is operated, the shift position corresponds to the operation position of the shift lever 10.

As shown in FIG. 3, an automatic position is provided on the lever guide 12 of the operation lever 10. When the operation lever 10 is operated to the automatic position and the shift lever 19 is operated to the reverse R, As will be described later, the seedling planting apparatus 6 is automatically raised, and this state will be described next. When the operating lever 10 is operated to the automatic position, the planting clutch 8 is operated to the transmission side in exactly the same manner as when the operating lever 10 is operated to the planting position, and the seedling planting device 6 is set from the rice field G. The seedling planting apparatus 6 is automatically moved up and down so that the height is maintained.

As shown in FIG. 4 and FIG.
0 is operated to the automatic position (step S
1) When the shift lever 19 is operated from the forward side F or the neutral stop position N to the reverse side R (step S2), the hydrostatic stepless transmission 15 is not operated to shift to the reverse side R, but is operated by the electric cylinder 16. It is held at the neutral stop position N (step S3). Next, the planting clutch 8 is operated by the motor 9 to the transmission interrupting side (step S4), the hydraulic cylinder 7 is extended by the control device 11 and the control valve 7, and the seedling planting device 6 is raised from the rice field G. (Step S
5) (corresponds to forced ascent means).

When the ascending operation of the seedling planting apparatus 6 is started as described above, the timer (not shown) sets the set time T.
Is started (step S6). in this case,
The set time T is the time required for the seedling planting device 6 to be completely lifted from the rice field G when the seedling planting device 6 is started to be lifted from the rice field G, or the link mechanism 4 shown in FIG. The time required to reach the upper limit is set.

When the raising operation of the seedling planting apparatus 6 is started as described above, the sensor float 13 descends to the lower limit of the set range due to its own weight or the like. Thereby, when the detected value A corresponding to the lower limit is input from the potentiometer 14 to the control device 11 before the set time T elapses after the raising operation of the seedling planting device 6 is started (step S8) (step S7). It is determined that the seedling planting device 6 has been completely raised from the rice paddle surface G, and it is determined that the seedling planting device 6 is in a normal state, and the control device 11 and the electric The speed of the hydrostatic stepless transmission 15 is shifted by the cylinder 16.
As a result, the aircraft starts to move backward (step S9) (corresponding to reverse control means).

Conversely, in step S5, the seedling plant 6
If the detected value A corresponding to the lower limit is not input from the potentiometer 14 to the control device 11 even after the set time T has elapsed since the start of the upward operation (steps S7 and S8),
Since soil or the like is caught in the support portion of the sensor float 13 and it can be determined that the sensor float 13 does not drop to the lower limit of the set range, in such a case, the hydrostatic continuously variable transmission 15 is set on the reverse side. The gear is not shifted to R, and the state held at the neutral stop position N by the electric cylinder 16 is maintained (step S10) (corresponding to reverse control means).

In such a state, the control unit 3 shown in FIG.
The worker who is sitting at the control section 3 descends from the control section 3 and goes to the seedling planting device 6 side, removes the soil etc. which is caught in the support portion of the sensor float 13, and manually moves the sensor float 13 to the lower limit of the set range. Perform an operation such as lowering to In this case, the detection value A corresponding to the lower limit is input from the potentiometer 14 to the control device 11 (step S11). However, the state in which the hydrostatic continuously variable transmission 15 is held at the neutral stop position N is assumed. Maintained (step S
10).

When the above operation is performed, the operator gets on the control unit 3 of FIG. 1 again, and thereafter, once returns the shift lever 19 operated on the reverse side R to the neutral stop position N ( If the shift lever 19 is again operated to the reverse R (Step S13), the control device 11 and the electric cylinder 16 move the shift lever 19 to the shift position corresponding to the operating position of the reverse R of the shift lever 19, and the hydraulic lever is turned off. The speed change operation of the stepped transmission 15 is performed, whereby the aircraft starts to move backward (step S9).

[First Alternative Embodiment] Instead of the control flow shown in FIG. 4, a control flow shown in FIG. 5 may be set. As shown in FIG. 5, the shift lever 19 is operated to the reverse side R to start the raising operation of the seedling planting device 6 (step S2).
1) When the detection value A corresponding to the lower limit is input from the potentiometer 14 to the control device 11 (step S22),
The change rate B of the detection value of the potentiometer 14 is detected (Step S23).

In this case, when the rate of change B is equal to or less than the set value C (corresponding to the set speed) (step S24), the sensor float 13 is slowly and slowly driven by its own weight or the like with the raising operation of the seedling planting device 6. Is determined to have dropped to the lower limit of the setting range. Thereby, it is determined that the seedling planting device 6 has been completely raised from the rice field G, and it is determined that the seedling planting device 6 is in a normal state, and the shift position corresponding to the operation position of the reverse side R of the speed change lever 19 shown in FIG. The hydrostatic type continuously variable transmission 15 is operated by the control device 11 and the electric cylinder 16 to perform the speed change operation, whereby the body starts to move backward (step S25) (corresponding to the reverse control means).

Conversely, if the sensor float 13 does not fall to the lower limit of the set range due to the soil or the like being caught in the support portion of the sensor float 13, the hydrostatic continuously variable transmission 15
Is maintained at the neutral stop position N, and in such a state, the worker sitting on the control unit 3 in FIG. To remove the soil and the like caught in the support portion of the sensor float 13 and perform an operation of lowering the sensor float 13 to the lower limit of the set range by hand.

As described above, when the operator manually operates the sensor float 13 to the lower limit of the setting range, the sensor float 13 is generally quickly operated to the lower limit. As a result, after the detection value A corresponding to the lower limit is input from the potentiometer 14 to the control device 11 (step S2).
2) If the change rate B of the detection value of the potentiometer 14 is larger than the set value C (step S24), it is determined that the operator has manually operated the sensor float 13 to the lower limit of the set range.

In this case, the detection value A corresponding to the lower limit is input from the potentiometer 14 to the control device 11, but the state in which the hydrostatic stepless transmission 15 is held at the neutral stop position N is maintained. (Step S26) (corresponds to reverse control means). Then, the operator again gets on the control unit 3 of FIG.
9 once to the neutral stop position N (step S2
7) If the shift lever 19 is operated to the reverse side R again (step S28), the control device 11 and the electric cylinder 16 move the hydrostatic stepless to the shift position corresponding to the operation position of the reverse side R of the shift lever 19. The speed change operation of the transmission 15 is performed, whereby the aircraft starts to move backward (step S25).

[Second Alternative Embodiment] Instead of the control flow shown in FIGS. 4 and 5, a control flow as shown in FIG. 6 may be set. As shown in FIG. 1, a seedling planting device 6 is connected to a link mechanism 4 driven up and down by a hydraulic cylinder 5 so as to be freely rollable around a longitudinal axis P2, and a rear portion of the link mechanism 4 is connected to a seedling planting device. 6 and double acting hydraulic cylinder 20
Are linked by Thus, the raising and lowering operation of the seedling planting device 6 can be performed by the hydraulic cylinder 5, and the rolling operation of the seedling planting device 6 around the longitudinal axis P <b> 2 can be performed by the hydraulic cylinder 20. In this case, as shown in FIG. 1, a pair of side floats 21 (corresponding to a ground contact body) are supported on the left and right sides of the seedling planting device 6 independently by a mechanical stopper or the like so as to be independently movable in a set range. A pair of potentiometers (not shown) for detecting the vertical angle of the side float 21 with respect to the seedling planting device 6 is provided.

Thus, at the planting position and the automatic position of the operating lever 10, the seedling planting device 6 is maintained at the set height from the rice field G based on the detection value of the potentiometer 14 of the sensor float 13. The seedling planting device 6 is automatically moved up and down by the hydraulic cylinder 5. And
The inclination of the seedling planting device 6 with respect to the rice field G is detected based on the difference between the detected values of the potentiometers of the left and right side floats 21, and the hydraulic cylinder 20 is moved so that the seedling planting device 6 is supported parallel to the rice field G. Thus, the seedling planting device 6 is automatically rolled.

In the above configuration, when the operating lever 10 is operated to the automatic position and the shift lever 19 is operated to the reverse side R as shown in FIG. (Step S31), the left and right side floats 21 shown in FIG. 1 descend to the lower limit of the set range due to their own weight and the like. As a result, the seedling planting device 6 starts to be lifted, and the detection values A corresponding to the lower limits from the potentiometers of the left and right side floats 21 are substantially simultaneously transmitted to the control device 1.
1 (step S32), it is determined that the seedling planting device 6 has been completely lifted from the rice field G, and is determined to be in a normal state. The hydrostatic stepless transmission 15 is operated by the control device 11 and the electric cylinder 16 to shift to the shift position where the vehicle is to be shifted, whereby the body starts to move backward (step S33) (corresponding to the reverse control means).

Conversely, at step S31, the seedling plant 6
If the detected value A corresponding to the lower limit is not input from the potentiometers of the left and right side floats 21 to the control device 11 (step S32), soil or the like may be left on the support portion of one or both of the left and right side floats 21. Since it can be determined that the side float 21 has not been lowered to the lower limit of the set range, the hydrostatic continuously variable transmission 15 is not shifted to the reverse side R in such a case. The state held at the neutral stop position N by the step 16 is maintained (step S34) (corresponding to the reverse control means).

In such a state, the control unit 3 shown in FIG.
The operator who is seated on the boat descends from the control section 3 and goes to the seedling planting device 6 side, removes soil and the like bitten in the supporting portion of the side float 21, and lowers the side float 21 by hand to the lower limit of the set range. Perform an operation such as lowering to In this case, the detection value A corresponding to the lower limit is input to the control device 11 from the potentiometers of the left and right side floats 21 (step S35), but the hydrostatic continuously variable transmission 15 is moved to the neutral stop position N. The held state is maintained (step S34).

When the above operation is performed, the operator gets into the control section 3 of FIG. 1 again, and thereafter, once returns the shift lever 19 operated to the reverse R to the neutral stop position N ( If the shift lever 19 is again operated to the reverse side R (step S37), the control device 11 and the electric cylinder 16 move the shift lever 19 to the shift position corresponding to the operation position on the reverse side R by the control device 11 and the electric cylinder 16. The speed change operation of the stepped transmission 15 is performed, whereby the aircraft starts to move backward (step S33).

The present invention can be applied not only to a riding type rice transplanter but also to an agricultural tractor in which a rotary tilling device (corresponding to a ground working device) is connected to a rear portion of the fuselage by a link mechanism so as to be able to move up and down freely. In this case, a rotary cover for lifting control, which is supported at the rear of the rotary tillable device so as to be able to swing up and down, may be used as the grounding body of the present invention.

Incidentally, reference numerals are written in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is an overall side view of a riding rice transplanter.

FIG. 2 is a diagram showing a linked state of a shift lever, an operation lever, a hydraulic cylinder for raising and lowering a seedling planting device, a hydrostatic stepless transmission, and the like.

FIG. 3 is a plan view of a lever guide of the operation lever.

FIG. 4 is a diagram showing a control flow when the shift lever is operated to the reverse side.

FIG. 5 is a diagram showing a control flow when the shift lever is operated to the reverse side in the first alternative embodiment.

FIG. 6 is a diagram showing a control flow when the shift lever is operated to the reverse side in the second alternative embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 5 Actuator 6 Ground work device 13, 21 Grounding body 15 Transmission device for traveling 19 Speed change device T Set time C Set speed R Speed change device reverse side G Ground

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) A01C 11/02 313-332 A01B 63/10

Claims (3)

(57) [Claims] 1. A ground working device (6) is connected to a rear portion of an airframe by an actuator (5) so as to be vertically movable, and a grounding body (13) grounded to the ground (G) is vertically movable within a set range. When the shift operation tool (19) for manually shifting the speed of the traveling transmission (15) provided to the working device (6) is operated to the reverse side (R), the actuator (5) is moved upward. And the grounding body (13) is set within the set range by the time the set time (T) elapses from the start of the ascent operation of the ground work device (6) by the forced ascending means. When the lower limit is reached, the vehicle is allowed to reverse by the traveling transmission (15), and
If the grounding body (13) does not reach the lower limit of the set range even after the set time (T) elapses from the start of the ascent operation of the ground work device (6) by the forcible ascending means, the traveling vehicle A lifting / lowering structure for a work vehicle, provided with reverse control means for preventing a reverse movement of the body by a transmission (15). 2. A ground working device (6) is connected to a rear portion of the fuselage by an actuator (5) so as to be able to move up and down freely, and a grounding body (13) grounded to the ground (G) is lifted up and down within a set range. When the shift operation tool (19) for manually shifting the speed of the traveling transmission (15) provided to the working device (6) is operated to the reverse side (R), the actuator (5) is moved upward. And the grounding body (13) reaches the lower limit of the set range at a lower speed than the set speed (C) as the ground work device (6) is raised by the forcible rise unit. Then, the vehicle is allowed to move backward by the traveling transmission (15), and the grounding body (13) is raised from the set speed (C) with the rise of the ground work device (6) by the forcible ascending means. Reaches the lower limit of the setting range at high speed If that, the transmission for the travel (15)
A work vehicle lifting and lowering structure for a work vehicle provided with a reverse control means for preventing a reverse movement of the body by the vehicle. 3. A ground working device (6) is connected to a rear portion of the fuselage by an actuator (5) so as to be vertically movable, and a pair of left and right grounding bodies (21) grounded on the ground (G) are vertically movable within a set range. When the shift operation tool (19) for artificially shifting the speed of the traveling transmission (15) is operated to the reverse side (R), the actuator (5) is provided in the ground work device (6). And the left and right grounding bodies (21) reach the lower limit of the set range substantially simultaneously as the ground work device (6) is raised by the forcible raising means. Then, the traveling transmission (1)
5) allows the aircraft to move backward, and even if the ground work device (6) is raised by the forcible lifting means, the grounding body (2)
If both or one of 1) does not reach the lower limit of the set range, the work vehicle is provided with reverse control means for preventing reverse movement of the body by the traveling transmission (15), and is lifted / lowered by the ground work device. Construction.