JPH1189350A - Paddy field working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice transplanter capable of not only enabling a lifting and lowering control by a sensitivity proper to a mud hardness of a paddy field but also enabling a proper lifting and lowering control based on the surface of the paddy field even in a largely tilted state of a traveling machine body in the front and rear direction. SOLUTION: This paddy field working vehicle has a controlling device 48 capable of freely exchanging a first controlling mode for setting an objective posture of a sensing float 18A based on an upper and lower displacement magnitude of a mud-surface float 18B changing the sinking amount from the surface of the paddy field corresponding to the mud hardness of the surface of the paddy field, and carrying out the lifting and lowering of a working device, with a second controlling mode for lifting and lowering the working device so that the sinking amount of the mud-surface float 18B from the surface of the mud field may be maintained at an objective value, and the controlling operation of the controlling device 48 is set so as to be automatically changed from the first controlling mode to the second controlling mode when the tilting value more than the set value of a traveling machine body in an up-in-front state is observed by a pitching sensor 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work device which is connected to a rear end of a traveling body so as to be able to move up and down freely, and which allows one of a plurality of ground floats provided in the work device to be mounted on a field of the work device. A control device that is configured as a sensing float that can swing around the axis of the horizontal posture so that the swing posture changes according to the surface height, and that raises and lowers the working device so as to maintain this sensing float at the target posture. More specifically, the present invention relates to a technique for automatically adjusting the elevation control sensitivity of a working device according to mud hardness in a field scene.

[0002]

2. Description of the Related Art There is a paddy field working machine constructed as described in Japanese Patent Application Laid-Open No. Hei 7-87817. In this conventional example, a field scene at a groove mark position of a grounding float and a grounding float are grounded. It is configured to include two ground members in contact with a non-land field scene, and to measure the depth of the groove trace of the ground float from the difference of the field scene level measured by each of the ground members. The control system includes a control system for automatically adjusting the sensitivity of the elevation control so as to increase the sensitivity of the elevation control when detected, and to decrease the sensitivity of the elevation control when a shallow groove mark is detected.

[0003]

In the prior art, since the control sensitivity is automatically adjusted by measuring the mud hardness of the field scene, the optimum control sensitivity corresponding to the field condition can be obtained without any trouble for the operator. This makes it possible to move up and down. However, in those equipped with a dedicated grounding member that measures the mud hardness of the field scene in contact with the field scene, it is difficult to increase the grounding area due to limitations in increasing the size of the grounding member, Even when relatively small irregularities are present in the field scene where the grounding float does not touch the ground, the measurement accuracy is limited because the grounding member measures the unevenness. The number of parts is increased due to the configuration using one grounding member, and since each grounding member is provided in a form protruding backward from the grounding float, breakage is liable to occur, so there is room for improvement. There is.

[0004] Further, taking a rice transplanter as an example, at the end of the transplanting operation, the transplanting operation of the seedlings may be continued while climbing the slope toward the ridge E as shown in FIG. However, when transplanting seedlings in a state where the traveling body 3 is inclined in the direction in which the front part is lifted, the attitude of the sensing float 18 with respect to the traveling body 3 is greatly lowered forward, and the sensing float 18 is set at the target. This significantly deviates from the posture and does not allow proper lifting control.

[0005] It is an object of the present invention to make it possible to perform elevation control with appropriate sensitivity to the mud hardness of a field, and to properly raise and lower the field based on the field scene even when the traveling body is greatly inclined in the front-rear direction. The point is that the paddy field working machine that enables control is rationally configured.

[0006]

According to a first feature of the present invention, as described at the outset, a working device is connected to a rear end of a traveling body so as to be able to move up and down, and the working device is connected to the working device. Any of the plurality of grounding floats provided is configured as a sensing float that is swingable around an axis in a lateral posture so that the swinging posture changes in accordance with the height of the working device relative to the field scene, In a paddy working machine equipped with a control device that raises and lowers the working device so as to maintain the sensing float in the target posture, any of the plurality of grounding floats other than the sensing float,
The mud float is configured to be vertically displaceable so that the amount of submersion with respect to the field scene changes in accordance with the mud hardness of the field scene, and the control device controls the sensing float based on the vertical displacement of the mud float. A first control mode in which the working device is raised and lowered by setting the target posture of the first control mode, and a second control mode in which the working device is raised and lowered so that the amount of submersion of the mud float into the mud surface is maintained at a target value. It is configured to be switchable, and its operation and effect are as follows.

According to a second feature of the present invention (claim 2), the vehicle body according to claim 1 is provided with an inclination sensor for measuring a forward and backward inclination, and when the inclination sensor measures an inclination less than a predetermined value. Performs the lifting and lowering of the working device in the first control mode, and when the tilt sensor measures a tilt equal to or more than a predetermined value, the control operation of the control device is performed so as to raise and lower the working device in the second control mode. The operation and the effect are as follows.

[0008] A third feature of the present invention (claim 3) is that in claim 1, a selection switch for selecting one of the first control mode and the second control mode is provided. Yes, its operation and effects are as follows.

A fourth feature of the present invention (claim 4) is that in claim 1, the sensing float is a pair of grounding floats arranged at symmetrical positions with respect to a center position in the lateral direction of the working device. The mud float is disposed at a position sandwiched between the sensing floats, and a signal from a mud sensor for measuring the amount of submersion of the mud float in the field scene is set as a target signal, and a pair of the detected floats is provided. In the point that the control operation of the control device is set to perform the lifting and lowering of the working device as an average value of the signal values of the respective sensing sensors corresponding to the feedback signal, its operation, and,
The effects are as follows.

According to the first feature, since the displacement operation of the grounding float having a large grounding area is measured by the mud hardness sensor, it is possible to reduce the influence of small irregularities on the field scene and to work on a horizontal field. When performing the control, the control device performs the elevation control in the first control mode to set the target attitude of the sensing float in accordance with the amount of sinking on the mud surface of the mud surface float, thereby reducing the mud hardness of the field scene. The lifting and lowering control of the working equipment can be performed with the corresponding optimal control sensitivity. When the ground work is performed in a state where the aircraft is largely inclined, such as when the ground work of the seedlings is continued while climbing the slope toward the ridge, the control device performs the elevation control in the second control mode. Thus, even when the sensing float is in an uncontrollable posture, the working device can be moved up and down based on the vertical displacement of the mud float.

According to the second feature, since the mode is automatically switched between the first control mode and the second control mode based on the measurement result of the tilt sensor, it is possible to perform elevation control in an optimal state for a work state. There is no need to artificially perform the switching operation.

According to the third feature, the control intended by the operator can be selected and performed at an arbitrary timing by operating the selection switch as needed.

According to the fourth feature, since the mud float is arranged on the center side in the left-right direction, the mud hardness of the mud at the center position of the field scene where the work is performed by the working device can be measured. Also, the sensing float is placed at the position sandwiching the muddy float, and control is performed so that the average attitude of each muddy float is the target attitude, so that even if the traveling body tilts in the horizontal direction, Control can be performed.

[Effect of the Invention] Therefore, in a state where the influence of the small unevenness of the field is eliminated, the appropriate sensitivity corresponding to the mud hardness of the field scene is automatically set to perform the elevation control of the ground working device. Thus, a paddy field working machine capable of appropriately controlling the lifting and lowering of the working device with reference to the field scene even when the traveling machine body is greatly inclined in the front-rear direction has been rationally configured (claim 1). Further, the working device can be automatically moved up and down in an optimal control mode based on the forward and backward inclination of the traveling machine body (claim 2). This makes it possible to perform proper ascent and descent control based on the mud hardness of the field scene at the most necessary position for the work even when the traveling machine body is inclined in the lateral direction (Claim 4). ).

[0015]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a drive-type front wheel 1 and a drive-type rear wheel 2 that are steered.
The engine 4 is mounted on the front part of the traveling body 3 provided with a hydraulic motor, and a hydrostatic continuously variable transmission 5 to which power from the engine 4 is transmitted and a transmission case 6 are arranged on the rear part of the traveling body 3. Also, a driver seat 7 is arranged at the center of the traveling body 3, and a hydraulic cylinder 8 is mounted on the rear end of the traveling body 3.
The seedling planting device A as a ground working device is connected via a link mechanism 9 driven up and down to form a riding type rice planting machine as a paddy working machine.

A lifting lever 10 is provided on the right side of the driver's seat 7 for controlling the raising and lowering of the seedling planting apparatus A and turning on and off a planting clutch (not shown). 11 and a forced lifting lever 19. The planting clutch is built in the transmission case 6 and permits the disengagement operation only when the transmission shaft 12 that transmits power from the transmission case 6 to the seedling planting device A is in a predetermined rotation phase. The planting arm (described later) of the seedling planting apparatus A is configured to shut off power in a posture avoiding contact with a field.

The seedling placement apparatus A includes a seedling table 13 on which a mat-shaped seedling W is placed, a transmission case 14 to which power from the transmission shaft 12 is transmitted, and a chain case 1 from the transmission case 14.
Rotary case 1 rotated by the power transmitted through 5
6, the rotary case 16 is provided with a pair of planting arms 17, each provided with four leveling floats 18 (an example of a grounding float) arranged as shown in FIG. 5, and configured for eight-row planting. At the rear end position of the seedling planting device A, a fertilizer application device B is provided, and at the time of work, the planting arm 17 cuts out the seedlings one by one from the lower end of the mat-shaped seedling W placed on the seedling placing stand 13 to produce a field scene. At the same time as planting in S, fertilizer B is configured to supply fertilizer under a field scene near the planted seedling.

The four leveling floats 18 are disposed symmetrically with respect to the center in the left-right direction, and a pair of outer portions of the four leveling floats 18 are placed on a field of the seedling planting apparatus A in the field. It is used as a sensing float 18A for measuring the surface height, and a pair of materials disposed inside the sensing float 18A are used in the field scene S.
Of the rear wheel 2
Is located between the two floats 18A and 18B on the left and right.

That is, as shown in FIG. 2, the sensing float 18A extends rearward from the planting depth adjusting shaft 21 which is rotatably supported by the seedling planting device A around an axis in a lateral posture. The support arm 22 is swingably supported around an axis P in a lateral posture with respect to the rear end position of the support arm 22, and is disposed in front of the float 18 </ b> A with respect to a link member 23 formed forward from the planting depth adjustment shaft 21. Supporting the sensing float 18
A is configured to be swingable around an axis P in a laterally oriented posture.

A potentiometer type level sensor 25 is supported so as to be swingable about an operation shaft 24 in a lateral posture with respect to the support arm 22, and an operation arm 24A provided on the operation shaft 24 and a fixed arm fixed to the sensing float 18A 26
And a rod 29 extending between a member 28 fixed to the planting depth adjusting shaft 21 and a member supporting the level sensor 25, so that the planting depth adjusting shaft 21
As long as the attitude of the main body of the level sensor 25 around the operation shaft 24 is changed at the time of the rotation operation to maintain the swinging attitude of the sensing float 18 with respect to the planting apparatus A constant, the level sensor 2
It is configured to maintain the posture of the operation arm 24A with respect to the five main bodies. Further, a compression coil type spring 32 is interposed between a member 31 which is vertically oscillated through an adjustment arm 30 fixed to the planting depth adjustment shaft 21 and a front portion of the sensing float 18A. By doing so, even when the planting depth adjusting shaft 21 is rotated, the biasing force of the spring 32 is not changed as long as the swinging posture of the sensor float 18 with respect to the seedling planting device A is kept constant. I have.

As shown in FIGS. 3 and 4, the mud float 1
8B is a longitudinally extending bracket 36 having a support shaft 35 formed in a lateral position with respect to a rear end position of the support arm 22 extending rearward from the planting depth adjustment shaft 21 at a rear position of the float 18B. By inserting into the elongated hole 36A of the posture,
The rear portion of the float 18B is swingably supported around the support shaft 35, and is supported so as to be vertically movable along the formation direction of the long hole 36A. The front portion of the float 18B is supported by a frame 38 of the seedling plant A via a bending / extending link member 37.

A spring 39 for holding the support shaft 35 at a central position in the vertical direction of the elongated hole 36A of the bracket 36,
39, and a plate 42 is supported by a plate-like support member 40 fixedly mounted on the side of the seedling planting device A so as to be vertically displaceable via link pieces 41, 41 operating in parallel quadruple type. And a potentiometer type mud hardness sensor 43 having an operation arm 43A that is rotated around an axis in a lateral orientation with respect to the plate 42. An operation rod 45 is provided between an operation arm 43A of the mud hardness sensor 43 and a support piece 44 fixed to an upper surface at an intermediate position in the front-rear direction of the mud float 18B.
By linking the link piece 41 supporting the mud hardness sensor 43 with the link member 55, the pivoting operation of the planting depth adjusting shaft 21 is performed by the vertical displacement of the support plate 42 linked with the swing of the support arm 22. Arm 43A and support piece 44
And the distance in the up-down direction is kept constant. As shown in the figure, in a side view, the support piece 44 is disposed at a position immediately above a point where the tip trajectory T of the planting claw 17A provided on the planting arm 17 intersects with the field scene S.

Further, since the mud surface float 18B is supported as described above, the rear support shaft 35 and the long hole 3 of the bracket 36 are provided.
6A and the front link member 37
The vertical displacement of the float 18B as a whole is permitted according to the mud hardness of the field scene S by the bending and stretching operation. In particular, since the float 18B is swingably supported around the support shaft 35 at the rear portion, even when the traveling body 3 is inclined in the front-rear direction, no excessive force is required to act on the support system, and as described above. Since the position of the support piece 44 is set, the amount of submersion of the float 18B with respect to the field scene S can be measured by measuring the voltage signal from the mud hardness sensor 43.

As shown in FIG. 6, a potentiometer type sensitivity setting device 47 which is operated by a dial 46 is disposed at a position in front of the driver's seat 7.
The lower the operation is, the lower the target attitude of the sensing float 18A is set, the lower the biasing force acting on the sensing float 18A from the spring 32 is, and the more sensitive the swing of the sensing float 18A is allowed. The more the operation is performed to the "dull" side, the more the biasing force acting on the sensing float 18A from the spring 32 is set by setting the target posture of the sensing float 18A to the forward rising side, so that the swing of the sensing float 18A is slowed. It is something to be done. Further, the mud surface float 18B measures the mud hardness of the field scene S based on the amount of subsidence with respect to the field scene S.
At the time of raising / lowering control, as the subsidence amount of the mud float 18B with respect to the field scene S is larger, the control sensitivity is increased by judging that the field scene S is softer, and the submersion amount of the mud float 18B with respect to the field scene S is smaller. It is used to judge that the field scene S is hard and to correct the control sensitivity to a lower side.

As shown in FIG.
Is configured to be operable along a path formed in the guide 34, and when the elevating lever 10 is operated forward from a “down” position in the path, the seedling planting apparatus A is lowered, and the “up”
When operated backward from the position, the seedling planting device A is raised,
When the operation is set to the "neutral" position, it is linked with the control system so as to maintain the seedling planting apparatus A at that level. In the control mode described later, the seedling planting apparatus A is automatically moved up and down, and when it is operated to the "off" position, the planting clutch is disengaged, and further, when the elevating lever 10 is set to the "automatic" position, According to the operation of the forced lifting lever 19,
The control system is linked to the control system so that it can be switched between a state in which the seedling planting apparatus A is automatically raised and lowered in a control mode described later and a state in which the planting clutch is disengaged and the seedling planting apparatus A is forcibly raised to the upper limit. ing.

As shown in FIG. 6, the forcible lifting lever 1
9 is urged by a spring (not shown) to return to the neutral position "N" in the non-operation state, and the neutral position "N"
When operating from above to the upward position "U" on the upper side, the planting clutch is disengaged to raise the seedling planting device A to the upper limit, and when operating from this neutral position "N" to the downward position "D" on the lower side, The system is linked with the control system so as to lower the ascending seedling planting device A until the leveling float 18 comes into contact with the ground.
When the seedling planting apparatus A is lowered by the forced lifting lever 19, the planting clutch is kept in the disengaged state, and after this lowering, the forced lifting lever 20 is again operated to the lowered position "D". Accordingly, the control operation is set so as to perform the operation of engaging the planting clutch.

As shown in FIG. 6, a control system of the rice transplanter is configured. In this control system, the control unit 48 having a microprocessor (not shown) is used to control the lifting lever 10.
, A signal from a changeover switch 50 provided at the base end of the forced lifting lever 19, a signal from the sensitivity setting device 47, a signal from the level sensor 25, and a signal from the mud. A hardness sensor 43, a potentiometer-type pitching sensor 51 (an example of an inclination sensor) for measuring the amount of forward and backward inclination of the traveling machine body 3, and a height of the seedling transplanting apparatus A relative to the traveling machine body are measured from the swing amount of the link mechanism 9. A system for inputting a signal from a link sensor 52 is formed, and an output system for controlling a solenoid valve 53 for controlling the hydraulic cylinder 8 is formed. The solenoid valve 53 has a characteristic of an electromagnetic proportional type in which the opening degree of the solenoid valve 53 increases as the value of the current supplied to the solenoid increases.

An automatic raising / lowering control routine for raising / lowering the seedling planting apparatus A is set as shown in the flowchart of FIG. That is, in this control, the pitching sensor 51
The inclination of the traveling body 3 in the front-rear direction is measured, and a flag is set to “0” when the inclination of the traveling body 3 toward the forward rising side is equal to or greater than a set value (this flag is an auxiliary It is determined whether the elevating lever 10 (used in the elevating control routine) is at the "automatic" position (steps # 101 to # 104). If it is determined in this determination that the position is other than the "automatic" position, a control target is set based on the signal from the sensitivity setting device 47, and the sum of the signal values from the left and right level sensors 25 is reduced by half. The average value is compared with a dead zone formed on the basis of the control target, and as a result of the comparison, if the average value is outside the dead zone,
The value corresponding to the deviation between the control target and the average value is set as the target opening of the solenoid valve 53, the elevation control is set on the side where the deviation is reduced, and the solenoid valve 53 is operated. If there is an average value in the range, the electromagnetic valve 53 is not operated (the neutral position is maintained), and the seedling planting apparatus A can perform the elevation control based on the field scene S by these processes. (Steps # 105 to # 109).

When the lifting lever 10 is set to the "automatic" position, the sum of the signal values of the left and right mud hardness sensors is averaged by a simple calculation of halving, and based on this average value. To correct the signal value from the sensitivity setting unit 47, and set this correction result as a control target (steps # 110 to # 111). The lifting control based on the field scene can be performed.

The inclination of the traveling body 3 in the front-rear direction is measured by the pitching sensor 51, and if it is determined that the inclination of the traveling body 3 to the front ascending side is equal to or larger than the set value (step 102). ), Auxiliary lifting control routine (# 200)
Step) is performed.

That is, this auxiliary lifting / lowering control routine corresponds to FIG.
When the flag is “0”, the signal value from the mud hardness sensor 43 during the automatic ascent / descent control until the traveling machine body 3 reaches the inclined state is averaged as shown in the flowchart of FIG. The value is set as a control target, the flag is set to "1", and the sum of the signal values from the left and right mud hardness sensors 43, 43 is averaged by a simple calculation of halving. If the average value is outside the dead zone as a result of the comparison with the dead zone formed based on the target,
The value corresponding to the deviation between the control target and the average value is set as the target opening of the solenoid valve 53, the elevation control is set on the side where the deviation is reduced, and the solenoid valve 53 is operated. If there is an average value in the range, the electromagnetic valve 53 is not operated (the neutral position is maintained), and the seedling planting apparatus A can perform the elevation control based on the field scene S by these processes. (Steps # 201 to # 208).

In addition, the control operation for performing the elevation control following the field scene S based on the signals from the level sensors 25, 25 in a state where the traveling body 3 is not tilted back and forth (the above-described # 105 to # 105)
109), the first control mode is constituted, and the second control mode is executed by the auxiliary elevating control routine (# 201 to # 208 steps).
Control mode is set.

In the second control mode, as shown in FIG. 10, when the traveling machine 3 continues the transplanting operation of the seedlings while climbing the slope toward the ridge E, the front portion of the traveling machine 3 The level sensor 2 is tilted in the lifting direction to exceed the measurement limit of the level sensor 25, or because the sensing float 18A cannot swing to an angle corresponding to this tilt,
In the second control mode, the control using the sensing float 18A is performed based on the displacement of the mud float 18B in the vertical direction in place of the control using the sensing float 18A. Then, the level of the seedling planting apparatus A with respect to the field scene S is measured, and the seedling planting apparatus A is moved up and down so as to maintain this level. The raising and lowering of the seedling planting apparatus A can be performed smoothly. In particular, in this embodiment, the inclination of the traveling machine body 3 is automatically switched based on the measurement result of the pitching sensor 51, so that it is possible to perform the ascending and descending in the optimal control mode without any labor for the operator. It has become something.

[Other Embodiments] The present invention can be configured as follows in addition to the above-described embodiment.

(A) As shown in FIG. 12, the present invention is applied to a six-plant seedling planting apparatus A having three leveling floats 18, and the floats on both right and left sides are detected by floats 18A,
18A, and the float at the middle position in the middle is a mud float 18B.

(B) As shown in FIG. 13, the present invention is applied to a 10-plant seedling planting apparatus A having five leveling floats 18, and the innermost floats on the left and right outer sides are set as sensing floats 18A, 18A. The float at the middle position between them is a mud float 18B.

(C) The arrangement of the sensing float 18A and the mud float 18B shown in the embodiment and the other embodiments (a) and (b) are interchanged, and the mud float 18B is outwardly arranged in the left-right direction. Are arranged, and the sensing float 18A is arranged inside in the left-right direction.

(D) A dedicated selection switch is provided to artificially switch between the first control mode and the second control mode.

(E) The control system of the present invention is applied to a direct sowing apparatus.

[Brief description of the drawings]

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

FIG. 2 is a side view of a sensing float.

FIG. 3 is a side view of a mud hardness detection float.

FIG. 4 is a rear view of the rear part of the mud hardness detection float.

FIG. 5 is a plan view showing the arrangement of a leveling float.

FIG. 6 is a block circuit diagram of a control system.

FIG. 7 is a plan view of the operation path of the lifting lever.

FIG. 8 is a flowchart of an automatic elevating control routine.

FIG. 9 is a flowchart of a correction lifting control routine;

FIG. 10 is a side view showing a working state in a climbing state with respect to a ridge according to the configuration of the present invention.

FIG. 11 is a side view showing a working state in a climbing state with respect to a ridge according to a conventional configuration.

FIG. 12 is a plan view showing a float arrangement according to another embodiment (a).

FIG. 13 is a plan view showing a float arrangement according to another embodiment (b).

[Explanation of symbols]

 3 Traveling Aircraft 18 Grounding Float 18A Detecting Float 18B Mud Float 48 Controller 51 Inclination Sensor A Working Device P Axis S Field Scene

Claims (4)

[Claims] 1. A working device is connected to the rear end of a traveling body so as to be able to move up and down freely, and one of a plurality of ground floats provided in the working device corresponds to the height of the working device with respect to a field scene. A paddy field machine equipped with a control float that is configured to be swingable around the axis of the sideways posture so that the swinging posture changes, and that raises and lowers the working device so that the sensing float is maintained at the target posture. Any of the plurality of ground floats other than the sensing float is configured as a mud surface float that can be displaced up and down so that the amount of sinking in the field scene changes in accordance with the mud hardness of the field scene. A first control mode in which the control device sets the target posture of the sensing float based on the vertical displacement of the mud float and moves the working device up and down, and the amount of submersion of the mud float to the mud surface Maintain the target value Second control mode and the paddy working machine that is configured to be freely switched to performing lifting of the working device as. 2. The vehicle according to claim 1, further comprising an inclination sensor for measuring a front-rear inclination, when the inclination sensor measures an inclination equal to or less than a predetermined value, the work apparatus is moved up and down in the first control mode. 2. The paddy field working machine according to claim 1, wherein the control operation of the control device is set so as to raise and lower the working device in the second control mode when the tilt sensor measures a tilt equal to or more than a predetermined value. 3. 3. The paddy working machine according to claim 1, further comprising a selection switch for selecting one of the first control mode and the second control mode. 4. The sensing float is constituted by a pair of grounding floats arranged symmetrically with respect to a center position in the lateral direction of the working device, and the mud float is sandwiched between the sensing floats. And a target signal is a signal from a mud surface sensor that measures the amount of subsidence of the mud surface float with respect to the field scene, and a feedback signal is an average value of the signal values of the respective sensor sensors corresponding to the pair of sensor floats. The paddy working machine according to claim 1, wherein the control operation of the control device is set so as to raise and lower the working device.