JPS6337784Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a combine harvester that cuts the grain culms planted in the field while traveling in the field, and threshes the harvested grain culms. The present invention relates to a cutting height adjusting device for adjusting the cutting height of a culm according to the length of a planted grain culm, the degree of lodging, field conditions, etc. More specifically, this invention combines manual control using a manual operation switch and a cutting height sensor to control the position change of an electromagnetic switching valve that switches and controls the supply and discharge of hydraulic oil to the hydraulic cylinder for raising and lowering the cutting section. The present invention relates to a cutting height adjusting device for a combine harvester, which is provided with an operation control circuit configured to selectively perform automatic control according to an output signal.

For example, in a combine harvester that controls the cutting height by raising and lowering the cutting section, a cutting height adjustment device that can select and switch between automatic control and manual control of the cutting height is disclosed in, for example, Japanese Patent Application Laid-Open No. It is already known as disclosed in Japanese Patent Application Laid-open No. 52-47428, Japanese Patent Application Laid-open No. 52-34226, and Japanese Utility Model Application Laid-open No. 54-14927. In such a cutting height adjustment device, switching from automatic control to manual control of the cutting is performed if the operator discovers large irregularities in the field or an obstacle such as a stone block on the field while automatically controlling the cutting height. In such cases, or if the operator discovers that the cutting height adjustment device is set to automatic control when moving the combine over a ridge, it may cause damage to the cutting section if left unattended. It is often carried out in response to emergency situations.

By the way, among the three publications mentioned above, JP-A-52-
The device disclosed in Publication No. 47428 generates a difference (potential difference) between the set value of the cutting height and the signal from the cutting height detector by changing the set value of the cutting height by operating a manual operation lever. This difference is sensed by a comparison mechanism to generate a reaping section lift signal, and the position change control of the electromagnetic switching valve is performed using the lift signal. In other words, the manual control system is provided in conjunction with the comparison mechanism of the automatic control system and utilizes the automatic control system as is. For this reason, in this known example, the automatic control circuit does not turn off even if manual control is performed, and depending on the state of the cutting height detector at that time, even if manual control is performed, manual control may not be activated. The comparison mechanism generates a signal that is the opposite of the reaping part elevation signal (ascent signal or descending signal) that was intended to be generated by operating the control lever, or a signal with a different value is generated, which is opposite to what the operator intended. This means that you can obtain different lifting and lowering operations and different amounts of lifting and lowering operations. Furthermore, the operator must compare the amount of operation of the manual operation lever and the amount of elevation of the reaping section, and if the amount of elevation is insufficient, the operator must operate the lever again. As described above, this known example is difficult to deal with in an emergency situation.

Next, the device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 52-34226 uses a manual operation lever to manually control the cutting height by operating a manual switch in the manual lifting control circuit. The reaping section can be raised or lowered by turning on the manual switch during control, but in this known example, the reaping section does not move even if the manual operation lever is moved to the lower position during automatic control of the cutting height. not descend,
The mowing section is configured to be lowered only while the mowing height detector generates a lowering signal. For this reason, it is not possible to lower the reaping section arbitrarily by manual control during automatic control. For example, when a large depression in the field is encountered, the reaping section cannot be manually lowered rapidly, or when a manual switch is turned on or off. It is not possible to control the mowing section to lower it at a coordinated speed by turning it off. In addition, as described above, in this known example, the manual switch for manual lifting is operated during automatic control to manually raise and lower the reaping section, so the above-mentioned manual operating lever is also used for automatic control during manual control. However, conversely, not only after switching the manual automatic changeover switch to the automatic lift control circuit side, but also after operating the manual operation lever to the up position during automatic control,
If the complicated operation, such as moving the manual operating lever to the lower position and turning on the lowering manual switch, is not performed correctly, the reaping section will continue to lower even if the lowering signal is issued from the reaping sensor. Automatic control of cutting height is not functioning properly. The above-mentioned lever operation is likely to lead to an erroneous operation such as accidentally operating the manual operating lever to the raised position instead of the lowered position, that is, a different erroneous operation unless automatic control is activated.

Next, the above-mentioned Japanese Utility Model Application No. 54-14927 discloses that when the manual switch in the manual lifting control circuit is turned on during the automatic control of the cutting height, the reaping section can be manually raised and lowered. At the same time, the automatic lift control circuit is turned off, giving priority to manual control. Therefore, the reaping section can be freely manually raised and lowered during automatic control of the cutting height, and when the manual switch is turned off after the reaping section has been raised and lowered, the automatic control state can be automatically returned. However, this known example also has certain problems because it does not give complete priority to manual control. In other words, in response to an emergency situation during automatic cutting height control, the reaping section is raised manually using the manual switch, and then when the manual switch is turned off, automatic control is restored and the mowing section is raised by the signal from the cutting height detector. A situation may occur in which the cutting part is lowered rapidly, and such rapid lowering may damage the cutting part.

As we have seen above, conventional cutting height adjustment devices prioritize manual control only within a certain limit, and do not take sufficient safety measures such as preventing damage to the cutting section. Nakatsuta.

The purpose of this invention is to give complete priority to manual control over automatic control to ensure sufficient safety, and at the same time, in contrast to the method disclosed in Japanese Patent Application Laid-open No. 52-34226, the cutting height is Although the structure is such that the reaping section is raised and lowered manually during automatic control and then returned to automatic control using a lever for manual control as in the same publication, the above return can be achieved reliably without any erroneous operation. The present invention aims to provide a novel cutting height adjustment device for a combine harvester.

Regarding the illustrated embodiment, the structure of the cutting height adjusting device for a combine harvester according to this invention will be explained as follows.
As shown in the figure, while the machine is traveling by the drive of the crawler 1, the planted grain culms are separated by the divider 3 at the lower front end of the cutting section 2 at the front of the machine.
The planted grain culm is pulled up by the grain culm pulling device 4 in , the planted grain culm is harvested at the base of the stock by the cutting blade 5, and the harvested grain culm is moved toward the threshing section 7 by the vertical conveyance belt 6. In a combine harvester configured to carry out threshing by transporting the harvested grain culm to the rear through a feed chain 8 on one side of the threshing part 7 and feeding the tip side of the grain culm into the threshing part 7. , this idea is implemented as follows.

That is, the above-mentioned reaping section 2 is normally
It is supported so that it can be raised and lowered, and the raising and lowering of the reaping section 2 is carried out by a single-acting hydraulic lift cylinder 9 shown in FIG.
It is carried out by. In order to control the operation of the hydraulic lift cylinder 9, an electromagnetic switching valve 10 shown in FIG. 2 is provided. This electromagnetic switching valve 10
The oil supply circuit 14 guides the hydraulic oil set in the pressure regulating valve 13 by the hydraulic pump 12 from the hydraulic tank 11 toward the hydraulic lift cylinder 9, and discharges the hydraulic oil from the hydraulic lift cylinder 9 direction to the hydraulic tank 11. The primary side is connected to the oil drain circuit 15. The electromagnetic switching valve 10, as shown in the figure,
The connection circuit 16 that connects the secondary side to the hydraulic lift cylinder 9 is blocked at the neutral position N, where the hydraulic lift cylinder 9 is maintained at a constant expansion/contraction position, and the oil supply circuit 14 is connected to the above connection circuit 16. and supply hydraulic oil to the hydraulic lift cylinder 9, and extend the cylinder 9 to raise the reaping part 2. A lowering action position D is provided for draining oil from the cylinder 9 and for lowering the reaping section 2 by its own weight. In the connection circuit 16 described above, there is a slow return valve 17 formed by connecting in parallel a check valve 17a that allows oil flow only in the direction of the hydraulic lift cylinder 9 and a variable throttle 17b.
It has been inserted. The electromagnetic switching valve 10 is displaced from the illustrated neutral position N to the downward operating position U by energizing the solenoid 18 and to the downward operating position D by energizing the solenoid 19, respectively. In the illustrated case, the vertical conveyance belt 6 is
In order to change the position of the joint end of the grain culm to the feed chain 8 according to the length of the harvested grain culm, the same hydraulic system is used to supply hydraulic oil to the double-acting vertical conveyance adjustment cylinder 20 for changing the posture. It is intended to supply. That is, as similarly shown in FIG.
A port is provided on the secondary side of the electromagnetic switching valve 10 to which the oil supply circuit 21 connected to the longitudinal conveyance adjustment cylinder 20 is connected, and the neutral position N and the lowering action position D of the electromagnetic switching valve 10 are The switching valve 1 is connected to the oil supply circuit 21 so that the oil supply circuit 14 is connected to the oil supply circuit 21.
It constitutes 0. Then, the above-mentioned oil supply circuit 2
1 and another oil drain circuit 22 connected to the oil drain circuit 15, and the extension oil chamber 20a and the contraction oil chamber 20 of the vertical conveyance adjustment cylinder 20.
Other electromagnetic switching valves 23 are provided, each having a secondary side connected to b. Other electromagnetic switching valves 23 include an oil supply circuit 21 and an oil drain circuit 2, as shown in the figure.
a neutral position N in which the vertical conveyance adjustment cylinder 20 is maintained at a constant extension/retraction position by connecting the two secondary ports and blocking both secondary ports; An extension action position I in which the reduction action oil chamber 20b is connected to the oil drain circuit 22 and the vertical conveyance adjustment cylinder 20 is extended, and an extension action position I in which the oil supply circuit 21 is connected to the reduction action oil chamber 20b and the extension action oil is The chamber 20a is connected to the oil drain circuit 22, and the vertical conveyance adjustment cylinder 20
and a reduction action position for performing a reduction operation. In FIG. 2, reference numeral 24 denotes a flow rate control valve consisting of a combination of a variable throttle 24a and a relief valve 24b, and is used to control the supply ratio of hydraulic oil to the vertical conveyance adjustment cylinder 20. The hydraulic supply and discharge mechanism described above is integrated into a hydraulic unit 25, and is installed at an appropriate location on the combine harvester shown in the figure.

As shown in FIGS. 1 and 3, the illustrated combine harvester is provided with a cutting height sensor 27 on the grass dividing pipe 26 that supports the divider 3 on one side of the cutting section 2. The cutting height sensor 27 includes a sled-shaped sensor arm 28 that is supported so as to be movable up and down and slides into contact with the field surface. On the arm shaft 29 on which the sensor arm 28 is attached, as shown in FIG. A pair of leg plates 31a, 31b and 3 sandwiching the outer peripheral edge of this photo interrupter 30.
Two support frames 31, 32 with 2a, 32b
are fixedly installed in the cutting height sensor 27 at appropriate intervals in the circumferential direction. One leg plate 31a, 32a of each support frame 31, 32 has a fifth
The light emitting diodes 33A and 34A shown in the figure are equipped, and the other leg plates 31b and 32b are equipped with phototransistors 33B and 34B shown in FIG. 5, respectively. These light emitting diodes 33A,
34A and photo transistors 33B, 34B
are connected in parallel as shown in Figure 5, one end is connected to the power supply terminal, and the other end is grounded.
It is provided. The cutting height sensor 27 has a sensor arm 28 that moves up and down while slidingly contacting the field surface.
Arm shaft 29 and photo interrupter 3 on it
As 0 is rotated, the photo
The notch groove 30a of the interrupter 30 is connected to each support frame 3.
When the 1st and 32nd positions are reached, each support frame 31,
Light from the light emitting diodes 33A, 34A on the support frames 31, 32 is supplied to the photo transistors 33B, 34B on the respective support frames 31, 32 through the cutout groove 30a.
The mowing height is detected from the height of the reaping section 2 above the ground by utilizing the ON operation of B and 34B. Light emitting diode 3 on support frame 31
3A and the photo transistor 33B detect the lower limit of the appropriate cutting height range, and the light emitting diode 34A on the support frame 32 and the photo transistor 34B detect the upper limit of the appropriate cutting height range.・The reaping section rising voltage signal is sent to the output circuit led from the emitter of the transistor 33B.
Vh and a reaper falling voltage signal V1 are selectively output to an output circuit derived from the emitter of photo transistor 34B. As shown in FIG. 3, the entire cutting height sensor 27 can be adjusted in its vertical position by rotating a bell crank 36 that is rotatable around a fulcrum shaft 35. 36 is rotatably biased in one direction by a tension spring 37 and is connected to an operating cable 38. The operating cable 38 is connected to the operator's seat 39 of the illustrated combine harvester (Fig. 1).
is guided to a mowing height set lever 40 provided nearby, and by displacing the mowing height set lever 40 in the direction of the arrow, the bell crank 36 is rotated and the vertical position of the mowing height sensor 27 is determined. It is possible to adjust the cutting height and set the cutting height according to the crop condition, field conditions, etc. using the cutting height sensor 27. In FIG. 3, reference numeral 41 denotes a lock plate that releasably locks the cutting height set lever 40.

The position change control of the electromagnetic switching valve 10 shown in FIG. 2 and described above is performed by the operation control circuit shown in FIG. As shown in FIG. 5, the solenoids 18 and 19 of the electromagnetic switching valve 10 are connected in parallel with surge absorption diodes 42 and 43, respectively, and have one end connected to a power supply terminal, and the other end connected to a power supply terminal. It is grounded and incorporated into the control circuit. In the ground circuit of each solenoid 18, 19, an NPN transistor 44 whose emitter is grounded,
45 is inserted, and each transistor 44,
The collector is connected to the base of 45. Other NPN transistors 46 and 47 whose emits are grounded are
It is provided. Transistor 4 in each of the above locations
6 and 47 have their collectors and bases connected to power supply terminals, respectively, and the bases of the transistors 46 and 47 at each location are selectively turned on by a manual operation lever 48 shown in FIG. Up operation switch 49 or down operation switch 5
It is grounded via 0. In FIG. 5, 51 is a battery constituting a power source, and 52 is a main switch 52 that connects and disconnects the battery 51 from the entire illustrated control circuit.

In the operation control circuit shown in Fig. 5, the configuration necessary for manual control of the cutting height is as described above.Before explaining the other circuit configurations, it is necessary to explain the operation during manual control. , as follows. That is, the manual operation lever 4 shown in FIG.
8 in one direction along arrow A to turn on the raising operation switch 49, the transistor 46
Since the base circuit of is grounded, no voltage signal is input to the base, and the transistor 46 is turned off, a base signal is input from the power supply side to the transistor 44 whose collector is connected to the base. The transistor 44 turns on, so that the solenoid 18
A current is conducted to energize the solenoid 18. Conversely, the manual operating lever 48 shown in FIG.
When the lower operation switch 50 is turned on by displacing it in the other direction along the arrow A, the base circuit of the transistor 47 is grounded and no voltage signal is input to the base, turning off the transistor 47. A base signal is input from the power supply side to the transistor 45 whose collector is connected to the base, and the transistor 45
5 is turned on, and as a result, current flows through the solenoid 19 and the solenoid 19 is energized. As mentioned above, when the solenoid 18 is energized, the electromagnetic switching valve 10 shown in FIG. It is moved to the working position D. Therefore, during manual control, the manual operation lever 48 is selectively displaced in the direction of arrow A in FIG.
9 and the lowering operation switch 50 are selectively turned on, the reaping section 2 can be raised and lowered, and the cutting height can be manually controlled.

Next, the output signal of the above-mentioned cutting height sensor 27 is
The circuit configuration for automatically controlling the cutting height according to Vh and Vl is explained with reference to Fig. 5.
The power circuit is a switch 53 with automatic control.
Through the circuit section direction for automatic control is guided. first and second NAND circuits 54,
55 are provided, and these NAND circuits 5
4 and 55, a power supply circuit is connected to a flip-flop 56, which will be described later, and a reaping clutch (not shown) for switching on and off the power transmission to the reaping section 2 of the combine harvester shown in the figure. It is connected via a reaping clutch interlocking switch 57 that is turned on when the reaping clutch is engaged, and an output circuit of the photo transistor 33B is further connected to the input terminal of the first NAND circuit 54, and a second NAND Further, the output circuits of the photo transistors 34B are connected to the input terminals of the circuits 55, respectively. Furthermore, third and fourth NAND circuits 58 and 59 are provided whose output terminals are connected to the bases of the transistors 46 and 47, respectively, and these third and fourth MAMD circuits 58 and 59 are At the input end, first and second
Output terminals of NAND circuits 54 and 55 are connected via inverters 60 and 61, respectively.
Further, a differentiation circuit 62 is provided connected to the power supply circuit led through the flip-flop 56 and the reaping clutch interlocking switch 57 described above.
The differential circuit 62 is connected to the power supply circuit via the flip-flop 56 and the reaping clutch interlocking switch 57, and a monomulti 63 is provided, and a pulse generating circuit 64 is connected to the output of both inverters 60 and 61 whose input terminals are described above. Diodes 65 and 66 at the ends allow signal transmission only in the direction of the generating circuit 64.
Connected and provided via. Then, the output terminal of the monomulti 63 and the output terminal of the pulse generation circuit 64 are connected to a third NAND circuit 58 and a fourth NAND circuit.
NAND circuit 59, NAND circuit 58,
They are connected via diodes 67 and 68 that allow signal transmission only in 59 directions. The above-mentioned monomulti 63 is equipped with a timer integration circuit 63a as shown in the figure, and operates by instantaneously dropping the power supply voltage Vcc led through the flip-flop 56 and the reaping clutch interlocking switch 57 to below a certain voltage. and a square voltage pulse _P a lasting t seconds
It is assumed that this will occur. The mono multi 63
The differentiation circuit 62 on the front stage side includes an inverter 62a that inverts the input signal, a capacitor 62b that generates a differential pulse upon receiving the output signal of the inverter 62a, and a capacitor 62b that cuts off the differential pulse when there is no input signal from the power supply side. Diode 62 for
c, and a capacitor 62d that instantaneously drops the power supply voltage upon receiving the differential pulse,
When a signal from the power supply side is input, the monomulti 63 is triggered to generate the pulse P _a . Further, the pulse generation circuit 64
It has a conventional configuration in which a NAND circuit 64a, an inverter 64b, a capacitor 64c, and a resistor are connected as shown, and generates intermittent voltage pulses _Pb in response to an input signal.

Here, obtained from the circuit configuration explained above,
To explain the operation during automatic control of the cutting height, when the automatic control is performed by turning on the automatic control switch 53, instead of selectively turning on the raising operation switch 49 and lowering operation switch 50 during manual control. , the increased voltage signal Vu selectively output from the third NAND circuit 58 and the fourth NAND circuit 59
The solenoids 18 and 19 are selectively excited by the falling voltage signal Vd selectively outputted from the lower voltage signal Vd. Considering the circuit structure described above, the above-mentioned rising voltage signal Vu and falling voltage signal Vd are output as low (L) level signals when the above-mentioned reaping section rising voltage signal Vh and reaping section falling voltage signal Vl are output, respectively, The third and fourth signals are output by outputting the same signals Vu and Vd.
Since the output ends of each of the NAND circuits 58 and 59 are grounded, when these signals Vu and Vd are selectively output, each of the NAND circuits 58 and 59 whose bases are connected to the output ends of the NAND circuits 58 and 59 is grounded. The transistors 46 and 47 are selectively turned off, and thus each transistor 44 and 45 is selectively turned on, as described for the manual control, thereby causing each solenoid 1 to turn on.
8 and 19 are selectively energized, so that the electromagnetic switching valve 10 shown in FIG.
and the lowering action position D. First, we will explain the effect when the automatic control switch 53 is turned on to switch to the automatic control state of the cutting height. , trigger Mono Multi 63,
The voltage pulse P _a described above is generated for t seconds (for example, 5-10 seconds), and this voltage pulse is applied to the third NAND.
The signal is input to a circuit 58 and a fourth NAND circuit 59. Therefore, when switching to automatic control as described above, the cutting height is determined by the cutting height sensor 2.
The sensor 2 is outside the appropriate range set to 7.
When the reaping section rising voltage signal Vh or the reaping section falling voltage signal Vl described above is output from 7, the signal Vh
The first NAND circuit 54 to which the signal Vl is input is connected to the third NAND circuit 58 via the inverter 60, and the second NAND circuit 55 to which the signal Vl is input is connected to the fourth NAND circuit 59 via the inverter 61. Therefore, in the output state of the reaping section rising voltage signal Vh, the third NAND circuit 58
operates and outputs the rising voltage signal Vu, and in the output state of the reaping part falling voltage signal Vl, the fourth NAND
Circuit 59 operates to output a falling voltage signal Vd.
This signal Vu or Vd activates solenoid 18 or 1.
9 is excited to raise or lower the reaping part 2, and the output pulse of the monomulti 63
Since P _a continues for t seconds, the raising or lowering of the reaping part 2 at this time is performed continuously,
The cutting height can be quickly changed within the appropriate cutting height range. The above is the effect when switching to automatic control, but in the steady state of automatic control, the differentiating circuit 62 does not operate and there is no pulse P _a output from the monomulti 63, so the mowing height sensor 27 detects the height of the cutting section. When the voltage signal Vh or the reaping section falling voltage signal Vl is output, the signal is input to the pulse generation circuit 64 via the first NAND circuit 54 and inverter 60 or the second NAND circuit 55 and inverter 61. , the pulse generation circuit 6
4 generates an intermittent voltage pulse P _b , and the pulse
P _b is input to the third NAND circuit 58 and the fourth NAND circuit 59 . Therefore, the first
The NAND circuit 54 connects the third
A second NAND circuit 5 connected to the NAND circuit 58
5 connects to the fourth NAND circuit 5 via an inverter 61
9, in the output state of the reaping section rising voltage signal Vh, the third NAND circuit 58 outputs the rising voltage signal Vu, and also outputs the reaping section falling voltage signal Vl.
In the output state, the fourth NAND circuit 59 intermittently outputs the falling voltage signal Vd in correspondence with each voltage pulse _Pb . Cutting height sensor 2
The reaping section 2 is raised or lowered stepwise by the intermittent output signal Vu or Vd of the NAND circuit 58 or 59, which is continuously output as long as the output signal Vh or Vl from the NAND circuit 58 or 59 is present. The cutting height is controlled to be within the appropriate range. In this way, by raising and lowering the reaping section 2 in stages under the steady state of automatic control, unexpected
Excessive lifting and lowering of the reaping section 2 and occurrence of shock can be avoided.

As shown in FIG. 5, an automatic control indicator lamp 69 has one terminal connected to the power circuit on the downstream side of the automatic control switch 53, and the other terminal is connected through a resistor 70 and an NPN transistor 71 connected in parallel. An automatic control indicator lamp 69 whose terminal is grounded is provided, and the base of the transistor 71 is connected to the secondary side of the reaping clutch interlocking switch 57 described above.
When the automatic control switch 53 is turned on, the automatic control indicator lamp 69 turns on the transistor 69 by inputting the base signal from the secondary side of the reaping clutch interlocking switch 57.
Lights up to indicate automatic control status.

As described above, in addition, a power supply circuit is connected to the input terminal of one NAND circuit 56a in the flip-flop 56, which is formed by interconnecting the input terminals and output terminals of the two NAND circuits 56a and 56b. Lifting operation interlocking switch 4 connected in parallel
9A and the lowering operation interlocking switch 50A are connected via an inverter 72. Also, the other NAND circuit 56 in the flip-flop 56
At the input end of b, the above-mentioned double interlocking switch 49A,
Although the 50A primary side power supply circuit is directly connected to supply voltage to the circuit section for automatic control as described above, it is not possible to branch it from the power supply circuit connected to the NAND circuit 56b. Two automatic control return switches 73A, 73B and another reaping clutch interlocking switch 57A are connected in parallel and inserted into the ground circuit. The above switches 49A, 50A and 57
Of A, the ascending operation interlocking switch 49A and the descending operation interlocking switch 50A are interlocked with the above-mentioned ascending operation switch 49 and descending operation switch 50, respectively, as shown in the figure, and the manual operation lever 48 shown in FIG. By displacing the manual operating lever 48 in one direction along the arrow A, the ascending operation switch 49 and the ascending operation interlocking switch 49A are simultaneously turned on, and by displacing the manual operating lever 48 in the other direction along the arrow A, the ascending operation switch 49 and the ascending operation interlocking switch 49A are turned on simultaneously. The operation switch 50 and the lowering operation interlocking switch 50A are designed to be turned on at the same time. The other reaping clutch interlocking switch 57A is interlocked with the reaping clutch interlocking switch 57 as shown in the figure, but whereas the reaping clutch interlocking switch 57 is turned on when the reaping clutch is engaged as described above, The other reaping clutch interlocking switch 57A is configured as a switch that is turned on when the reaping clutch is disengaged.

Based on the above, during the automatic cutting height control with the automatic control switch 53 turned on, the manual operation lever 48 is displaced in the direction of arrow A in FIG. 6, and the raising operation switch 49 and the raising operation interlocking switch 49A are Alternatively, if the lowering operation switch 50 and the lowering operation interlocking switch 50A are turned on, not only the same manual control as described above is performed by operating the same lever 48, but also the manual control is performed even though the automatic control switch 53 is turned on. The control state will be maintained. The reason is that the lift operation interlocking switch 49
By turning on the A or lowering operation interlocking switch 50A, the voltage signal of the power supply circuit is inverted by the inverter 72 and applied to the flip-flop 56, so there is no output from the flip-flop 56, and considering the characteristics of the flip-flop, This is because the state without the same output continues. That is, the circuit section including the flip-flop 56 is
A manual control holding circuit is configured to maintain the manual control state, and when the holding circuit is in the operating state, the base signal of the transistor 71 disappears and the automatic control display lamp 69 goes out. The function of the manual control hold circuit including flip-flop 56 is to connect the input side of the hold circuit to automatic control return switch 73A or 73B.
Alternatively, once the other reaping clutch interlocking switch 57A is turned on and grounded, it is released. That is, these switches 73A, 73
B and 57A are provided for the purpose of canceling such functions.

FIG. 6 shows an operating section provided near the operator's seat 39 of the illustrated combine harvester. As shown in FIG.
5, and is movable not only in the direction of arrow A but also in the direction of arrow B shown in FIGS. 6 and 7, which is perpendicular to the direction of arrow A. And the above-mentioned automatic control return switch 73
A and 73B are arranged on each side of the operating end of the manual operation lever 48 as shown in FIG. 7, and when the manual operation lever 48 is displaced in one direction along arrow B, one automatic control return switch is activated. 73A
However, when the switch is displaced in the other direction, the other automatic control return switch 73B is turned on.

Therefore, during harvesting work under automatic control of the cutting height, for example, when turning the machine around the edge of a ridge, the manual operation lever 48 is operated in the direction of arrow A, and the raising operation switch 49 is turned on. When the operator rotates the machine after the reaping section 2 has risen slightly, and then lowers the reaping section 2 again by turning on the lowering operation switch 50, the operator should press the manual operation lever 48. Hold it and arrow B
The automatic control return switch 73A or 7 is activated by operating the lever 48 in one direction or the other along the
By obtaining the ON operation of 3B, it is possible to easily return to the automatic control state. Returning to this automatic control state can also be performed by once disengaging the reaping clutch and then turning on the other reaping clutch interlocking switch 57A. When returning to automatic control like this, if there is an output signal Vh or Vl from the cutting height sensor 27, the cutting height is quickly adjusted as in the above-mentioned switching from manual control to automatic control. Change control is performed. In the illustrated case, the power supply circuit is connected to the circuit for automatic control via the reaping clutch interlocking switch 57, so unless the reaping clutch is engaged and the interlocking switch 57 is turned on, automatic control will not occur. It is safe because the reaping section 2 cannot be raised or lowered by control.

As shown in FIG. 6, the above-mentioned automatic control switch 53 and automatic control display lamp 69 are also provided in the operating section near the cockpit 39. The operating section is also provided with a gear shift lever 76 for changing the vehicle speed of the illustrated combine harvester and other operating members.

As explained above, the cutting height adjustment device for a combine harvester of this invention controls the position change of the electromagnetic switching valve 10 that switches and controls the supply and discharge of hydraulic oil to the hydraulic cylinder 9 for raising and lowering the reaping section. Manual control by switching operation of manual operation switches 49 and 50 and output signal Vh of cutting height sensor 17,
A cutting height adjusting device is provided with an operation control circuit configured so that it can be selectively controlled by either automatic control according to Vl,
In the operation control circuit, the manual operation switch 4
Manual control holding circuits 49A, 50A, 56, 72 that maintain the manual control state when switches 9, 50 are operated, and automatic control return switches 73A, 73B for canceling the function of the manual control holding circuits are provided. At the same time, the automatic control return switches 73A and 73B are replaced with the manual operation switch 4.
9 and 50, the switching operation is performed by operating the manual operating lever 48 in a direction different from the switching operation direction, and the above-mentioned manual control holding is performed. By installing a circuit, even during automatic control of the cutting height, once the manual operation switch is operated, the manual control state is maintained and maintained, so for example, when turning the machine in the field. Before harvesting or when an obstacle is found in the field, the reaping section is raised by operating the manual operation switch, and then the automatic control is activated and the reaping section is lowered rapidly to prevent damage to the reaping section. Risks that may occur are avoided and safety is ensured. Moreover, the mowing height adjusting device of this invention is provided with an automatic control return switch as described above, and this return switch is switched by a manual operation lever for switching a manual operation switch for manual control. Since the structure is configured so that the automatic control state can be obtained by operating the mowing height automatically, the same operation can be performed after manually raising or lowering the cutting section from the automatic cutting height control state. It is easy to operate, allowing you to easily return to the automatic control state by using the manual operating lever used in There are also things that are leading to a decrease in the number of species.

In other words, this invention is such that once manual control is performed using the manual operation lever 48 during automatic control of the cutting height, the manual control state continues even if the operation of the operation lever 48 is stopped. By giving complete priority to control, workers can safely raise the reaping section manually and then slowly lower it manually by repeatedly turning the manual operation switch on and off. After that, it is possible to return to the automatic control state using automatic control return switches 73A and 73B, thereby ensuring high safety.

Furthermore, the device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 52-34226 is a manual control lever for manual control, that is, a lever that is selectively operated between a raised position and a lowered position. To obtain a return to automatic control by an operation that is likely to lead to an erroneous operation, such as once the switch is turned on, that is, when the manual operation lever is moved to the up position by mistake and the manual switch for raising is turned on. However, in this invention, the return to the automatic control state is achieved by automatic control return switches 73A and 73B, which are switches different from the manually operated switches 49 and 50 for manual control. In this case, a return to automatic control is obtained by operating a manual operating lever 48 for manual control, and a return to automatic control is obtained by operating the same lever 48 in a direction different from the operating direction for manual control. Therefore, although the number of levers has been reduced and the structure of the operating system has been simplified, there is no possibility of erroneous lever operations where people thought they had returned to automatic control but actually did not.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a combine harvester equipped with an embodiment of this invention, Fig. 2 is a circuit diagram of a hydraulic circuit in the combine, Fig. 3 is a perspective view showing the main parts of the embodiment, and Fig. 4 is a perspective view of a combine harvester equipped with an embodiment of the invention. A perspective view of the main parts of the same embodiment,
FIG. 5 is a circuit diagram of the operation control circuit in the same embodiment, FIG. 6 is a perspective view showing a part of the combine harvester, and FIG. 7 is a longitudinal cross-sectional view of a part of the part shown in FIG. 6. 2...Reaping section, 9...Hydraulic lift cylinder, 1
0... Solenoid switching valve, 18, 19... Solenoid,
27... Mowing height sensor, 28... Sensor arm, 29... Arm axis, 30... Photo interrupter, 30a... Notch groove, 31, 32... Support frame, 33A, 34A... Light emitting diode, 33
B, 34B...Photo transistor, 44, 4
5... Transistor, 46, 47... Transistor, 48... Manual operation lever, 49... Lifting operation switch, 49A... Lifting operation interlocking switch, 5
0...Descent operation switch, 50A...Descent operation interlocking switch, 53...Switch with manual control, 54, 55...NAND circuit, 56...Flip-flop, 58, 59...NAND circuit,
60, 61... Inverter, 62... Differential circuit,
63...Mono multi, 64...Pulse generation circuit,
69...Automatic control display lamp, 71...
Transistor, 72...Inverter, 73A, 7
3B...Automatic control return switch, 74...
...Spherical seat, 75...Ball.

Claims (1)

[Scope of utility model registration request] The position change control of the electromagnetic switching valve that switches and controls the supply and discharge of hydraulic oil to the hydraulic cylinder for raising and lowering the reaping section is performed by manual control using the switching operation of a manual operation switch and automatic control according to the output signal of the cutting height sensor. The mowing height adjusting device is provided with an operation control circuit configured to selectively perform either one of the mowing heights, and when the manual operation switch is operated in the operation control circuit, A manual control holding circuit for holding the control state and an automatic control return switch for canceling the function of this manual control holding circuit are provided, and the above-mentioned automatic control return switch is operated by switching the manual operation switch. 1. A cutting height adjustment device for a combine harvester, characterized in that a switching operation is performed by operating a manual operating lever in a direction different from the switching operation direction.