JPH10295136A - Automatic cutting height controller for combine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an automatic cutting height control function from being operated contrarily at the time of manually elevate/lower-operating a cutting part and to surely and automatically restore automatic control function at the time of starting cutting operation in this case. SOLUTION: This cutting height automatic controller for a combine automatically controlling a cutting cylinder detecting the cutting height of a cutting part by a cutting height sensor 76 and elevating/lowering the cutting part to make a target cutting height stops automatic control when the cutting cylinder is manually operated and carry out the automatic restoration of suspended automatic control when a state where the grain straw sensor 37 of the cutting part detects grain straws, a state where the moving back sensor 151 of a machine body does nor detect moving back and a state where the detecting value of the sensor 76 is lower than the upper limit of an automatic control range continue while the machine body travels in a fixed time. In addition raising control for raising a cutting part is continued while automatic traveling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combine for continuously cutting and threshing grain culms.

[0002]

When the automatic control functions when the reaper is manually lifted and lowered, the operation is contrary to each other.
It is necessary to stop the automatic control during the manual elevating operation (manual priority of the automatic cutting height control). In addition, if the automatic control is returned by a manual operation, the operation becomes complicated, especially in a mowing operation at a ridge or the like, so it is necessary to automatically return the automatic control.
Further, it is necessary to perform this automatic return so that the harvesting operation is not performed without returning to the actual state despite the return.

[0003]

According to the present invention, a cutting height of a cutting unit is detected by a cutting height sensor, and a combine cutting device for automatically controlling an actuator for raising and lowering the cutting unit to a target cutting height. In the height automatic control device, when the actuator is manually operated, the automatic control is stopped, and the automatic return of the stopped automatic control is performed, with the grain culm sensor of the mowing unit detecting the grain culm, The state in which the reverse sensor of the body does not detect backward movement and the state in which the detection value of the cutting height sensor is equal to or less than the upper limit value of the automatic control range are performed when the body continues running for a fixed distance.

[0004] Further, during the suspension of the automatic control, the ascending control for elevating the cutting unit is continuously performed.

[0005]

Embodiments of the present invention will be described below in detail with reference to the drawings. Fig. 1 is an overall side view of the combine, Fig. 2
Is a plan view of the same, in which (1) is a track frame on which the traveling crawler (2) is mounted, (3) is a machine frame installed on the track frame (1), and (4) is a feed chain (5). Threshing unit which stretches to the left and incorporates a handling cylinder (6) and a processing cylinder (7); (8) a cutting unit provided with a cutting blade (9) and a grain culm transport mechanism (10); ) Is a hydraulic cutting cylinder for raising and lowering the cutting unit (8) via the cutting frame (12), (13) is a straw cutter facing the end of the straw chain (14), and (15) is from the threshing unit (4). A grain tank for carrying the grains of the above-mentioned through a fryer (16), (17) a discharge auger for carrying out the grains of the tank (15) out of the machine, (18) an operation unit (19) and Driver's seat (20)
The driving cabin with (21) is the driving cabin (1)
8) An engine provided below, configured to continuously cut and thresh grain culms.

Further, as shown in FIGS. 3 and 4, a raising case (2) for 6 rows having raising tines (23) for raising uncut culms which are taken in through weeding plates (22).
4) ..., a six-stroke star wheel (25) and a scraping belt (26) that scrape the stem side of the raised grain stalk, and a cutting blade that cuts the scraped grain stem (S). 9) and the lower right transport chain (2
7) and the upper right transport tine (28), and the central lower transport chain that joins the cut culm of the central two rows to the rear lower right transport chain (27) and the vicinity of the feed intermediate position of the upper right transport tine (28). (29) and the upper center transport tine (3
0) and the cut culm for the left two rows are transported to the lower right transport chain (2
7) and a lower left transport chain (31) and an upper left transport tine (32) which join near the feed end position of the upper right transport body (28); and 6 which merges with the feed end of the lower right transport chain (27). A vertical transport chain (33) for inheriting and transporting the root side of the harvested grain culm of the row, and the upper right transport tine (2)
8) a rear upper transport tine (34) for transporting the spike end side of the cut stalk culm for 6 rows that joins the feed end to the threshing unit (4);
A chain before auxiliary transfer (35) and a chain after auxiliary transfer (3) which are provided at the feed end portion of the vertical transfer chain (33) and carry over the harvested culm in a proper posture to the feed chain (5).
6) is provided in the cutting section (8) for cutting 6 rows, the cut and harvested culm for 6 rows is inherited and joined to the vertical transport chain (33), supplied to the feed chain (5), and threshed. It is composed.

Further, the left middle right scraping belt (2)
6) Fixing the upper left limit switch type middle and right culm sensor (37) on the upper side, and the uncut mower scraped into the scraping belt (26) until just before cutting the root by the cutting blade (9). The sensor (37) senses the middle part of the cereal stem and detects whether or not the harvesting operation is being performed based on the presence or absence of the left, middle, and right cereal stems, and also detects the front of the handling cylinder (6) of the threshing unit (4). A long culm sensor (38) and a short culm sensor (39) are provided in the handling port, and the change in the culm length of the grain culm fed to the handling drum (6) by the nipping and transporting of the feed chain (5) is detected by each sensor (38) ( 39). In addition, the feed start end of the vertical transport chain (33) is connected to the cutting frame (1) via the transport input case (40) which also serves as a handling depth adjusting fulcrum shaft.
2) and an electric depth motor (41) for swinging the feed end portion of the vertical transport chain (33) to the deep or shallow position at the center of the transport input case (40). By the forward / reverse control of 41), the feed end of the vertical transport chain (33) is brought into contact with or separated from the feed start end of the auxiliary transport pre-chain (35), and the grain culm handling depth by the handling cylinder (6) is changed. Long and short culm sensors (38) (3)
Based on the detection result of 9), the handling motor (41) is automatically controlled to keep the handling depth of the harvested grain culm fed to the handling drum (6) substantially constant, and the left middle right grain culm sensor (37) The start of the mowing operation is detected when at least one of the stalks is turned on by the raked stalks, and the ending of the mowing operation is performed when all of the left middle right stalk sensors (37) are turned off. It is configured such that automatic control is performed to keep the handling depth constant during detection and harvesting.

Further, as shown in FIG. 5, a drive shaft (43) with a universal joint for transmitting the power of the engine (21) to the counter case (42) is provided, and a threshing output shaft (44) and a sorting output shaft (45). ), Reaping output shaft (4
6) The traveling output shaft (47) is provided on the counter case (42). The handling cylinder (6) and the processing cylinder (7) are V-belt driven through a threshing pulley (48) provided on the threshing output shaft (44), and a dust feeding fan (49) and a Karamin (5)
0) 1st conveyor (51), 2nd conveyor (52),
The swing drive shaft (53), the suction / discharge dust fan (54), and the straw cutter (13) are connected to the selection pulley (5) of the selection output shaft (45).
5) to drive the V-belt.

Further, a working hydraulic pump (56) is provided on the drive shaft (43), and hydraulic oil in a counter case (42) which also serves as an oil tank is supplied to the cutting cylinder (11) and the like to operate. At the same time, the power of the drive shaft (43) is transmitted to the sorting output shaft (45) via the threshing clutch (57), and the threshing output shaft (44) is connected to the sorting output shaft (45). The power is transmitted to each unit through the threshing unit (4) via the power supply. Also, the power of the suction / discharge fan (54) is supplied to the feed chain (5) via the feed chain clutch (58).
It is configured to tell.

Also, the power of the drive shaft (43) is transmitted to the reaping output shaft (46) via the constant speed clutch (59), and the reaping input single shaft (60) for driving each part of the reaping unit (8). , An input pulley (61) is provided, a cutting shaft (62) is connected to the one shaft (60), and a cutting unit (8) is provided.
It transmits power to each part, and the cutting frame (12)
The one shaft (60) is provided on a lifting fulcrum shaft (63) of a mowing part (8) that supports a base, and is auxiliary-transported to the left end of the one shaft (60) via a reduction gear (64) and a sprocket (65). The rear chain (36) is configured to be connected.

Furthermore, a pair of left and right traveling crawlers (2)
(2) is provided with a traveling speed change case (66) and a hydraulic continuously variable transmission (6) incorporating a hydraulic pump and a hydraulic motor.
7) is attached to a traveling transmission case (66), a transmission (67) is belt-connected to the traveling output shaft (47), and the transmission (67) is constantly rotated by the power of the engine (21). The left and right traveling crawlers (2) and (2) are driven by the speed change output of (67) via the speed change gear in the speed change case.

A vehicle speed tuning output shaft (68) is provided on the traveling speed change case (66), and the output shaft (68) is increased / decreased and rotated in proportion to the forward traveling speed of the traveling crawler (2). The pulley (61) of the cutting input single shaft (60) and the input pulley (61) of the cutting input single shaft (60) are connected via a tension pulley type cutting clutch (71). To connect the belt. Also, the cutting output shaft (46) is connected to a vehicle speed tuning pulley (70) by a belt, and when the cutting clutch (71) is engaged, the vehicle speed tuning output shaft (68) rotates at a low speed and the rotation speed of the cutting output shaft (46). When the rotation speed is lower than the rotation speed, the shaft (60) is driven by the cutting output shaft (46), while the rotation speed of the vehicle speed tuning output shaft (68) is higher than the rotation speed of the cutting output shaft (46) in a high-speed running state. And the vehicle speed tuning output shaft (68)
Thus, one shaft (60) is driven, and the mowing unit (8) is driven at a speed proportional to the traveling speed.

Further, as shown in FIG. 6, a cutting switch (72) for raising and lowering the cutting unit (8) is provided, and a manual switch (73) for raising and lowering the cutting unit (8) by manual operation; A lift switch (74) for automatic lifting and lowering, which performs an operation of raising the cutting unit (8) at the working height to the turning height and an operation of lowering the cutting unit (8) at the turning height to the cutting work height; Potentiometer type up-and-down sensor (7
5), the grain culm sensor (37), the cutting height sensor (76) for detecting the ground height of the cutting unit (8), and the cutting unit (8) lifting control by operating the cutting cylinder (11). And an on / off switch that is turned on when the main speed change lever (150) disposed in the operation section (19) is in the reverse position and turned off when it is in the other neutral and forward positions. , A running (forward straight) distance sensor (152) which is a counter that counts the number of revolutions of the output shaft (68), and a cutting height setting device (152) that sets a target cutting height. 153) and an automatic return height setting device (15) for setting the automatic return height of the automatic control.
4) and an automatic return distance setting device (155) for setting an automatic return distance of the automatic control, the cutting and raising / lowering controller (72).
Connected to At the time of cutting, the cutting cylinder (11) is automatically controlled based on the detection value of the cutting height sensor (76) and the target cutting height so as to eliminate the difference therebetween, and the cutting height of the grain culm by the cutting blade (9). The lift sensor (75) detects the height of the cutting unit (8) with respect to the main unit by automatically controlling the cutting height to keep the cutting height substantially constant and turning on the lift switch (74). Automatic height control (auto-lift) to raise the mowing part (8) at the cutting height automatic control height to the turning height at the field headland (at the ridge), or the mowing part at the turning height at the field headland The automatic lowering control (auto setting) for lowering (8) to the automatic control height of the cutting height is performed.

When the mowing section (8) is moved up and down by manual operation of the manual switch (73), the automatic cutting height control is stopped. The manual priority of the automatic control prevents conflict with the control of the mowing elevating controller (72), and allows the manual adjustment and the automatic control to be performed appropriately.

Further, the automatic return of the suspended automatic control is
When at least one of the cereal stalk sensors (37) is on, the reversing sensor (151) is off, and the value detected by the cutting height sensor (76) is automatically set to the target cutting height. The travel distance sensor (15) is in a state where the height is equal to or less than the automatic return height obtained by adding the height set by the device (154).
The travel distance detected in 2) is the automatic return distance setting device (15
This operation is performed when the automatic return distance set in step 5) is continuous, that is, when it is detected that the mowing operation has been reliably started. This automatic return does not set the automatic return height to be higher than the automatic control range of the cutting height, but is set within the automatic control range. Thus, it is possible to prevent the mowing work from being performed in a state where the automatic control does not function. Also, at the time of automatic return, the presence or absence of a grain stalk in the cutting unit (8) is determined by the grain stalk sensor (37), so that the cutting height sensor ( 76)
Even when the detection value of becomes low, it is prevented from being automatically restored by mistake.

During the suspension of the automatic cutting height control, the automatic ascent control (auto lift) is continuously performed. Thereby, the cutting unit (8) during the suspension of the automatic cutting height control.
Is prevented from penetrating into the ground.

The feed chain clutch (5)
8) an electric feed chain motor (78) for turning on and off;
A forward rotation relay (79) and a relay switch (80) for turning off the motor (78); and a reverse rotation relay (81) and a relay switch (82) for turning on the motor (78) in a feed chain clutch (58). A limit switch (83) for stopping the motor (78) at the reverse rotation or the forward rotation position, and a power supply (84) is alternately applied to the relays (79) and (81) via the limit switch (83). The motor (78) is alternately rotated forward and reverse to a position where the limit switch (83) is switched, and the feed chain clutch (58) is turned on and off.

Further, an electric cutting motor (85) for turning on and off the cutting clutch (71), a reverse rotation relay (86) and a relay switch (8) for turning on and off the motor (85).
7), a forward rotation relay (88) and a relay switch (8) for disengaging the motor (85) with the cutting clutch (71).
9) and a limit switch (90) for stopping the motor (85) at the reverse rotation or the forward rotation position, and a power supply (84) is alternately provided to each of the relays (86) and (88) via the limit switch (90). And the motor (85) is alternately rotated in the forward and reverse directions to a position where the limit switch (90) is switched, so that the cutting clutch (71) is turned on and off.

A clutch relay (91) and a relay switch (92) for operating the relays (79), (81), (86), and (88) of the motors (78), (85) are provided. ), The relay switch (92) is switched, and the motors (78)
(85) The clutch (58) (71) The on / off operation is started substantially simultaneously, and the clutch lever (9) is started.
3) The clutch on / off manual switch (94) that is turned on / off by manual operation, and the reaping elevating controller (7)
2) Connect the clutch relay (9) to the manual switch (94).
A clutch switch (95) for manual / automatic switching for selectively connecting 1) is provided. Then, the clutch relay (9) is connected to the manual switch (94) via the clutch switch (95).
1) is connected, the motors (78) and (85) are operated by manual operation of the clutch lever (93), and the feed chain clutch (58) and the reaping clutch (71) are turned on and off. Is connected to a clutch relay (91) via a clutch switch (95), the clutch relay (91) is turned on / off by an automatic control signal output from the controller (72), and the motors (78) and (85) are operated. The clutch (58) (71) is turned on and off by operating the lift switch (74) so that the cutting unit (8) rises from the automatically controlled cutting height to the turning height (auto lift). The motors (78) and (85) are operated to perform an automatic control operation for disengaging the clutches (58) and (71). When the mowing part (8) is lowered from the turning height to the automatically controlled height of mowing by operating the switch (74), the motors (78) and (85) are operated to operate the clutches (58) and (71). The automatic control operation (auto clutch control) for turning on the clutch is performed.

As shown in FIGS. 6 and 9, a switch lever (not shown) for operating a handle depth adjusting switch (not shown) for adjusting the handle depth to the front and left and right of the knob (150a) of the main shift lever (150). 160) and the manual switch (7
3) A switch lever (73a) for operating the switch is provided, and an auto lift button (74a) and an auto set button (74a) for operating the lift switch (74) are provided on the right side of the knob (150a) on the driver's seat (20) side. 74b), and a hand-cutting clutch on / off switch (161) provided in parallel with the manual switch (94), and a hand-cutting clutch switch for turning the switch (161) on and off at the center of the rear surface of the knob (150a). A button (162) is provided, and the switches (73), (74), and (161) can be operated while the knob (150a) of the main shift lever (150) is held.

With this arrangement, when the main shift operation, the cutting elevating operation, and the cutting clutch operation are performed in a complicated manner, such as in the cutting operation (edge cutting) at the bank, fine operations that cannot be completely controlled by the automatic clutch can be performed. It can be operated at hand, and can be used separately from the auto clutch function, so that operation does not conflict. In addition, each switch (1
61), the clutches (58) and (71) can be turned on and off even when the mowing controller (72) fails.

Further, as shown in FIG. 7, the feed chain motor (78) and the mowing motor (85) have the same structure, and the motors (78) and (85) are provided with a deceleration case (9).
6) and the output shaft (9) of the reduction case (96).
7), the clutch arm (98) is fixed, and the link (10) is connected to the clutch arm (98) via the pin (99).
0), the clutch wire (101) is connected to the link (100), and the clutch arm (98) is rotated around the output shaft (97) to thereby connect the clutch wire (101).
To operate the feed chain clutch (58) or the reaping clutch (71), and the clutch arm (98) is reversely rotated about the output shaft (97).
The feed chain clutch (58) or the mowing clutch (71) is engaged by loosening the clutch wire (101). The feed chain motor (78) rotates the clutch arm (98) forward and backward by about 170 degrees to feed chain. The clutch (58) is turned on, and the clutch arm (98) is moved to about 190 by the cutting motor (85).
The mowing clutch (71) is turned on by rotating the mowing clutch (71) forward and backward, the mowing unit (8) stops after the feed chain (5) stops, and the mowing unit (8) operates after the feed chain (5) operates. Make up. The feed chain motor (7
8) and the mowing motor (85) are rotated in opposite directions to disengage (or engage) the clutches (58) and (71), and engage the clutches (58) and (71) such as the clutch arm (98). The cutting operation parts are configured to have substantially the same specification structure by the feed chain motor (78) mechanism and the mowing motor (85) mechanism.

This embodiment is constructed as described above. As shown in the flowchart of FIG. 8, when the manual switch (73) for performing the manual lifting operation of the mowing unit (8) is off,
The height of the main body of the reaping unit (8) is detected by the input of the elevation sensor (75), and the reaping unit (8) is placed in an automatic control range of the reaping height to keep the ground height of the reaping unit (8) substantially constant. When descending, the height of the cutting unit (8) is detected by the input of the cutting height sensor (76), and the cutting blade (9) is detected while the cutting culm is detected by the culm sensor (37). 2) The automatic cutting height control operation of keeping the cutting height of the cereal stem substantially constant is performed, and the culm is continuously cut and threshed.

When the harvesting operation is started, a clutch relay (91) is connected via a clutch switch (95).
Is connected to the controller (72), the mowing unit (8) moves down to the automatic control range of the mowing height, whereby a clutch engagement control signal is output from the controller (72), and the clutch relay ( 91) to excite the relay switch (92), to excite the forward rotation relay (88) to cause the mowing motor (85) to rotate forward, and to excite the reverse rotation relay (81) to excite the feed chain motor (7).
8) is reversed, the feed chain clutch (58) is engaged by the reverse rotation of the feed chain motor (78), and the feed chain (5) is operated.
The cutting clutch (71) is turned on by the forward rotation of, the cutting section (8) is operated, and each limit switch (83) (90)
Are switched, and the motors (78) and (85) are stopped and maintained.

When the harvesting operation is being performed by the automatic control of the cutting height, the lift switch (74)
Is turned on, the culm sensor (37) is turned off, the reaping culm disappears, and it is determined that the headland has been reached, so that the reaping cylinder (11) is raised and the automatic control is performed. An operation of raising the cutting unit (8) is performed, and when the cutting unit (8) rises to a turning height at the headland on the field, a clutch disengagement control signal is output from the controller (72), and a clutch disengagement control signal is output. The relay (91) is turned off, the relay switch (92) is switched, and the reverse rotation relay (8
The excitation of (6) causes the mowing motor (85) to rotate in the reverse direction, and the excitation of the forward rotation relay (79) causes the feed chain motor (78) to rotate in the forward direction.
After the feed chain clutch (58) is turned off by the forward rotation of 8) and the feed chain (5) stops, the cutting clutch (71) is turned off by the reverse rotation of the cutting motor (85) and the cutting section (8). Stops and each limit switch (8
3) (90) is switched and each motor (78) (85) is stopped and maintained. In this way, with the feed chain (5) and the mowing part (8) stopped, the operator performs a turning operation on the headland of the field, turns the direction, and turns to the next stroke work position.

When the lift switch (74) is turned on after reaching the next stroke operation position, the cutting cylinder (11) is lowered by the control of the lift valve (77), and the cutting section (8) is moved. When the mowing unit (8) is lowered to the automatically controlled height of the cutting height before turning, a clutch engagement control signal is output from the controller (72), and the clutch relay (91) is excited. Then, the relay switch (92) is switched, the cutting motor (85) is rotated forward by exciting the forward rotation relay (88), and the feed chain motor (7) is excited by exciting the reverse rotation relay (81).
8) is reversed, the feed chain clutch (58) is engaged by the reverse rotation of the feed chain motor (78), and the feed chain (5) is operated.
The cutting clutch (71) is turned on by the forward rotation of, the cutting section (8) is operated, and each limit switch (83) (90)
Are switched, and the motors (78) and (85) are stopped and maintained. In this way, the feed chain (5) and the cutting unit (8) are operated, and the automatic control of the cutting height is automatically returned,
The harvesting work in the next process is performed.

When the harvesting operation is being performed by the above-described automatic control of the cutting height, if the cutting switch (8) is moved up and down by operating the manual switch (73), the automatic control of the cutting height is temporarily stopped. The automatic control is suspended until the automatic return condition is satisfied. When the automatic return condition is satisfied, it is determined that the mowing operation has been started reliably and the automatic control is stopped. Control is automatically returned.

[0028]

As is apparent from the above embodiment, according to the present invention, the cutting height of the cutting unit (8) is detected by the cutting height sensor (76), and the cutting unit (8) is adjusted to the target cutting height. A cutting height automatic control device of a combine for automatically controlling a cutting cylinder (11) for raising and lowering, when the cutting cylinder (11) is manually operated, the automatic control is stopped, and the stopped automatic control is automatically restored. The state in which the grain culm sensor (37) of the mowing unit (8) is detecting the grain culm, the state in which the body's reverse sensor (151) does not detect reverse, and the detection of the cutting height sensor (76). The state in which the value is equal to or less than the upper limit of the automatic control range is performed when the aircraft continuously travels for a certain distance, and the manual control of the automatic control prevents conflict with the control of the reaping elevating controller (72). Suitable for manual adjustment and automatic control It can be carried out in. In addition, since the automatic control is automatically returned when it is detected that the harvesting operation has been started, the automatic control is stopped again despite the automatic recovery, and the harvesting operation is performed in a state where the automatic control does not function. It is possible to prevent the stalks and to automatically return the stalk sensor (37) to the cutting section (8).
The cutting section (8) is used to determine the presence or absence of grain culm in
Even when the detection value of the cutting height sensor (76) becomes low, such as when passing over a ridge, it is possible to prevent erroneous automatic return, and therefore, automatic return of the automatic control of the cutting height is reliably performed. Is what you can do.

Further, the ascent control for raising the reaping unit while the automatic control is stopped is continuously performed, so that the reaping unit (8) can be prevented from plunging into the ground while the automatic control is stopped.

[Brief description of the drawings]

FIG. 1 is an overall side view of a combine.

FIG. 2 is an overall plan view of the combine.

FIG. 3 is an explanatory side view of a cutting unit.

FIG. 4 is an explanatory plan view of a reaper.

FIG. 5 is a combine drive system diagram.

FIG. 6 is a diagram of a cutting control circuit.

FIG. 7 is an explanatory diagram of a feed chain motor and a mowing motor.

FIG. 8 is a flowchart of cutting and lifting control.

FIG. 9 is an explanatory diagram of an upper grip portion of the main transmission lever.

[Explanation of symbols]

 (8) Cutting unit (11) Cutting cylinder (37) Grain stalk sensor (72) Cutting raising / lowering controller (76) Cutting height sensor (151) Reverse sensor

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Ritsuko Kajioka 1-32 Chayacho, Kita-ku, Osaka City Yanmar Agricultural Machinery Co., Ltd.

Claims (2)

[Claims] 1. A cutting height sensor detects a cutting height of a cutting section,
In a cutting height automatic control device of a combine that automatically controls an actuator that raises and lowers a cutting unit so as to reach a target cutting height, when the actuator is manually operated, the automatic control is stopped, and the stopped automatic control is stopped. Automatic return, a state in which the grain stalk sensor of the mowing unit is detecting the grain stalk, a state in which the body's reverse sensor does not detect reverse,
An automatic cutting height control device for a combine, wherein the detection value of the cutting height sensor is equal to or less than the upper limit value of the automatic control range when the aircraft continuously travels a predetermined distance. 2. The combine cutting height automatic control device according to claim 1, wherein the raising control for raising the cutting unit is continuously performed while the automatic control is stopped.