JPS603699Y2 - Combine cutting height adjustment device - Google Patents

Description

[Detailed description of the device] This device is designed to reduce the height of the reaped part during harvesting, and therefore to reduce the height of the culm during harvesting. The present invention relates to a cutting height adjusting device for adjusting the cutting height according to the length of a planted culm, the degree of lodging, field conditions, etc.

More specifically, this invention uses manual control using the switching operation of a manual operation switch and manual control using 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.

Techniques for adjusting the cutting height by selectively displacing the solenoid valve for raising and lowering the cutting part in accordance with a signal from a cutting height sensor in a combine harvester are disclosed in, for example, Japanese Patent Laid-Open No. 52-34226 and Japanese Patent Laid-Open No. 52-4742. This method is already known as disclosed in Japanese Patent Application Laid-open No. 52-47428 and Japanese Utility Model Application No. 54-14927.

However, in the conventional type, the solenoid valve is positioned at the raising or lowering position as long as the cutting height sensor generates a raising or lowering signal, so the cutting section is frequently raised and lowered in a hunting manner. As a result, the cutting section tends to rise and fall rapidly and excessively.

Such a phenomenon makes the control of the cutting height unstable and causes the problem of poor cutting, and if the cutting section descends suddenly or excessively due to inertia, the tip of the cutting section may become unstable. By plunging into the soil, a shock is generated and components are likely to be damaged.

This type of shock is especially likely to occur when the combine harvester is moved around the edge of a field, when the reaping section is raised to a high position using manual control, and then switched to automatic control to lower the reaping section after the combine has been moved around. This is likely to occur when the cutting section is lowered rapidly to the position detected by the cutting height sensor.

However, if you try to prevent the occurrence of shock by repeatedly lowering the reaping section after the combine harvester has descended and stopping the descent intermittently, the reaping section will not be able to reach the proper cutting height position. It takes time to descend, and the reaping section starts reaping work midway through its descent, resulting in a tendency for high reaping.

Therefore, this invention controls the cutting height stably and precisely to eliminate component damage and poor cutting, and also allows the lowering of the cutting section after the combine is rotated without shock, and eliminates the above-mentioned tendency to cut at a high level. A new combine harvester height adjustment device that allows cutting to be done relatively quickly.
This is what we are trying to provide.

Regarding the illustrated embodiment, the configuration of the cutting height adjustment device for a combine harvester according to this invention will be explained. As shown in FIG. The planted culm is divided by the divider 3 at the lower front end, and the planted culm is pulled up by the culm lifting device 4 in the cutting section 2, and the planted culm is removed from the plant by the cutting blade 5. The harvested husk culm is conveyed to the direction of the threshing section 7 by the vertical conveyance belt 6, and then transferred to the foot chain 8 on the side of the threshing section 7.
This invention is implemented in the combine harvester configured to thresh by transporting the harvested husk culm rearward and feeding the tip side of the husk into the threshing section 7. There is.

That is, the above-mentioned reaping section 2 is supported so as to be movable as usual, and the elevating and lowering of the reaping section 2 is performed by a single-acting hydraulic lift cylinder 9 shown in FIG.

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 connects the oil tank 11 to the hydraulic pump 1.
2, an oil supply circuit 14 that guides the hydraulic oil of the hydraulic pressure set by the pressure regulating valve 13 toward the hydraulic lift cylinder 9, and an oil drain circuit 15 that discharges the hydraulic oil from the hydraulic lift cylinder 9 direction to the oil tank 11. -The next side is connected.

As shown in the figure, the electromagnetic switching valve 10 has a neutral position N in which the end of the connection circuit 16 connecting the secondary side to the hydraulic lift cylinder 9 is blocked and the hydraulic lift cylinder 9 is maintained at a constant expansion/contraction position; A lifting position U in which the oil supply circuit 14 is connected to the above-mentioned connection circuit 16 to supply hydraulic oil to the hydraulic lift cylinder 9, and the cylinder 9 is extended to raise the reaping section 2, and the above-mentioned connection circuit 16 is connected to an oil drain circuit 15 to drain oil from the hydraulic lift cylinder 9, and a lowering position for allowing the reaping section 2 to descend under its own weight.

The connection circuit 16 described above includes a check valve 17a that allows oil flow only in the direction of the hydraulic lift cylinder 9, and a variable throttle 17.
The slow return valve 17 formed by connecting 7b in parallel,
It has been inserted.

The electromagnetic switching valve 10 moves from the neutral position N shown in the figure to the solenoid 1.
8 is energized, the solenoid 19 is moved to the upward action position U, and the solenoid 19
are respectively displaced to the lowering action position by the excitation of .

In the illustrated case, a double-acting mechanism is used to change the posture of the vertical conveyance belt 6 so that the position of the culm joining end of the conveyance belt 6 to the foot chain 8 is changed in accordance with the length of the reaped culm. Hydraulic oil is also supplied to the vertical conveyance adjustment cylinder 20 of the mold by the same hydraulic system.

In other words, as shown in FIG. 2, a port is provided on the secondary side of the electromagnetic switching valve 10 to connect the oil supply circuit 21 that extends in the direction of the vertical conveyance adjustment cylinder 20. The switching valve 10 is configured such that the oil supply circuit 14 is connected to the oil supply circuit 21 at the neutral position N and the downward operating position of the valve 10.

The primary side is connected to the oil supply circuit 21 described above and another oil drain circuit 22 that is connected to the oil drain circuit 15, and the extension oil chamber 20a and the contraction oil chamber 20b of the vertical conveyance adjustment cylinder 20. Other electromagnetic switching valves 23 are provided, each having a secondary side connected to the two.

The other electromagnetic switching valve 23 is connected to the oil supply circuit 21 as shown in the figure.
and the oil drain circuit 22 and block both secondary ports to maintain the vertical conveyance adjustment cylinder 20 at a constant extension/retraction position. The oil supply circuit 21 is connected to the extension oil chamber 20a. At the same time, the reduction oil chamber 20b is connected to the oil drain circuit 22, and the vertical conveyance adjustment cylinder 20 is extended to the extension operation position (2), and the oil supply circuit 21 is connected to the reduction oil chamber 20b. The extension oil chamber 20a is connected to the oil drain circuit 22, and a reduction action position (2) is provided in which the vertical conveyance adjustment cylinder 20 is caused to perform a reduction operation.

In FIG. 2, 24 indicates a variable throttle 24a and a relief valve 2.
4b, and is used to control the supply ratio of hydraulic oil to the vertical conveyance adjustment cylinder 270.

The hydraulic supply and discharge mechanism described above is unitized as a hydraulic unit 25, and is installed at an appropriate location on the main machine of 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 the cutting section 2 side.

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 to which the sensor arm 28 is attached, as shown in FIG. 4, a disc-shaped photo-interrupter 30 having a cutout groove 30a on the outer periphery is mounted. Also, a pair of leg plates 31a, 31b and 32a, 32b cover the outer peripheral edge of this photo interrupter 30.
Two support frames 31, 32 with 2 support frames 31, 32 are fixedly mounted in the cutting height sensor 27 with a suitable circumferential spacing between them.

One leg plate 31a, 32a of each support frame 31, 32 has light emitting diodes 33A, 34A shown in FIG. 5, and the other leg plate 31b, 32b has photo transistors 33B, 34B shown in FIG. 5, respectively. It is equipped.

These light emitting diodes 33A. 34A and phototransistors 33B and 34B are connected in parallel as shown in FIG. 5, with one end connected to a power supply terminal and the other end grounded.

The cutting height sensor 27 detects a notch in the photo-interrupter 30 as the sensor arm 28 moves up and down while slidingly contacting the field surface, and as the arm shaft 29 and the photo-interrupter 30 thereon are rotationally displaced. When the groove 30a reaches each support frame 31.322, the groove 30a reaches each support frame 31゜3.
The light from the light emitting diodes 33A, 34A on each support frame 31.
The mowing height is detected from the ground height of the reaping section 2 by utilizing the fact that the phototransistor 33Bt34B is turned on by the cutout groove 30a.

The light emitting diode 33A and phototransistor 33B on the support frame 31 set the lower limit of the appropriate cutting height range to the support frame 32.
Upper light emitting diode 34A and phototransistor 34
B detects the upper limit of the appropriate mowing height range, and at the same time, a reaping section rising voltage signal vh is output to the output circuit derived from the emitter of the phototransistor 33B, and is also derived from the emitter of the phototransistor 34B. The reaped lower positive voltage signal (1) is selectively outputted to the output circuits.

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. , are biased to rotate in one direction by a tension spring 37, and are connected to an operating cable 38.

The operating cable 38 is guided to a cutting height set lever 40 provided near the operator's seat 39 (FIG. 1) of the combine harvester shown in the figure, and the bell is activated by displacing the cutting height set lever 40 in the direction of the arrow. The rotational displacement of the crank 36 is obtained to adjust the vertical position of the mowing height sensor 277, and the mowing height can be set on the mowing height sensor 27 in accordance with the operating state, field conditions, etc.

In FIG. 3, reference numeral 41 denotes a lock plate that locks the cutting height set lever 40 in a unlockable manner.

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 each have a diode 42 for surge absorption.
．． 43 in parallel, one end is connected to a power supply terminal, the other end is grounded, and incorporated into the control circuit.

Into the ground circuit of each solenoid 18, 19, a NPN transistor 44, 45 with a grounded emitter is inserted.
The collectors are connected to the bases of these transistors 44, 45, and the emitters are grounded. Another NPN transistor 46.
47 is provided.

Each of the other transistors 46, 47 has its collector and base connected to a power supply terminal, respectively, and the base of each of the other transistors 46, 47 is selected by a manual operating lever 48 shown in FIG. It is grounded via a rise operation switch 49 or a fall operation switch 50 which are turned on.

In FIG. 5, 51 is a battery constituting a power source;
2 is a main switch that connects and disconnects the entire illustrated control circuit and the battery 51;

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, when the manual operation lever 48 shown in FIG. 6 is displaced in one direction along the arrow A and the upward operation switch 49 is turned on, the base circuit of the transistor 46 is grounded and no voltage signal is input to the base. Since 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 its base, and the transistor 46 is turned off.
4 is turned on, and as a result, current is conducted to the solenoid 18 and the solenoid 18 is energized.

Conversely, when the manual operation lever 48 shown in FIG. 6 is moved in the other direction along the arrow A and the lowering operation switch 50 is turned on, the base circuit of the transistor 47 is grounded and no voltage signal is input to the base. transistor 4
7 is turned off, a base signal is input from the power supply side to the transistor 45 whose collector is connected to the base of the transistor 47, and the transistor 45 is turned on. This causes current to flow through the solenoid 19 and turn off the transistor 45. Solenoid 19 is energized.

As mentioned above, depending on the excitation of the solenoid 18, the second
The electromagnetic switching valve 10 shown in the figure is moved to the upward action position U, and conversely, by energizing the solenoid 19, the electromagnetic switching valve 1
0 is moved to the lower working position.

Therefore, during manual control, the manual operation lever 48 is selectively displaced in the direction of arrow A in FIG. 6, and the raising operation switch 49 and the lowering operation switch 50 are selectively turned on. The mowing height can be manually controlled.

Next, the output signal Vh of the above-mentioned cutting height sensor 27,
The circuit configuration for automatically controlling the cutting height in accordance with Vl will be explained with reference to FIG. 5. The power supply circuit is guided through an automatic control switch 53 toward a circuit section for automatic control.

First and second NAND circuits 54 and 55 are provided, and a power supply circuit is connected to the input terminals of these NAND circuits 54 and 55 to a flip-flop 56 to be described later and to the reaping section 2 of the combine harvester shown in the figure. It is connected via a reaping latch interlocking switch 57 that is turned on when the reaping latch is engaged in conjunction with the on/off of a reaping latch (not shown) for turning on and off the power transmission of the first N.
The input terminal of the AND circuit 54 is further connected to the output circuit of the phototransistor 33B, and the input terminal of the second NAND circuit 55 is further connected to the output circuit of the phototransistor 34B.

Further, third and fourth NAND circuits 5 whose output terminals are connected to the bases of the transistors 46 and 47, respectively, are provided.
8.59 are provided, and these third and fourth N
At the input terminals of the AND circuits 58 and 59, first and second
The output terminals of the NAND circuits 54 and 55 are connected to the inverter 60.
61, they are connected to each other.

Further, a differentiating circuit 62 is provided connected to the power supply circuit led through the flip-flop 56 and the reaping latch interlocking switch 57 described above, and this differentiating circuit 62, the flip-flop 56 and the reaping latch interlocking switch 5
A monomulti 63 is provided connected to the power supply circuit via 7, and a pulse generating circuit 64 is connected to the output terminals of both inverters 60 and 61, whose input terminals are connected to the above-mentioned inverters 60 and 61. It is connected through diodes 65 and 66 that allow this.

Then, the output end of the monomulti 63 and the output end of the pulse generation circuit 64 are connected to a third NAND circuit 58 and a fourth NAND circuit 59, respectively.
Diodes that allow signal transmission only in the direction 67.68
I want to connect via.

The above-mentioned monomulti 63 is equipped with a timer integration circuit 63a as shown in the figure, and operates by instantly lowering the power supply voltage Vcc led through the flip-flop 56 and the reaping latch interlocking switch 57 to below a certain voltage. It is assumed that a rectangular voltage pulse Pa is generated that connects the .

The differential circuit 62 on the front stage side of the monomulti 63 includes an inverter 62a1 that inverts the input signal.
capacitor 6 that generates a differential pulse upon receiving the output signal of
2b1 Equipped with a diode 62C1 to cut off the differential pulse when the input signal from the power supply side disappears, and a capacitor 62d to instantly drop the power supply voltage upon receiving the differential pulse, so that the signal from the power supply side is input. triggers the monomulti 63 when the pulse P
Let us generate a.

Further, the pulse generating circuit 64 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.

Now, to explain the function obtained from the above-described circuit configuration during automatic control of the cutting height, when automatic control is performed by turning on the automatic control switch 53, the raising operation switch 49 and Instead of selectively turning on the lowering operation switch 50, the rising voltage signal Vu selectively output from the third NAND circuit 58 and the fourth NAND circuit 5
Solenoids 18 and 19 are selectively excited by the falling voltage signal Vd selectively outputted from solenoid 9 .

Considering the circuit structure described above, each of the above-mentioned rising voltage signals Vu
, the falling voltage signal Vd is output as a low (L) level signal when the above-mentioned reaping section rising voltage signal vh and reaping section lower voltage signal are output, and the third. Since the output end side of each of the fourth NAND circuits 58 and 59 is grounded, each of the signals Vu,
When Vd is selectively output, each NAND circuit 58.59
Each transistor 46 has its base connected to the output terminal of
47 is selectively turned off, and therefore each transistor 44, 45 is selectively turned on, as described for the manual control, and thereby each solenoid 18, 19 is selectively energized. As a result, the solenoid valve 10 shown in FIG. 2 is selectively moved to either the upward operating position U or the downward operating position.

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. te, mono multi 6
3 to generate the aforementioned voltage pulse Pa for t seconds (e.g. 5-10 seconds), and this voltage pulse triggers the third N
The signal is input to an AND circuit 58 and a fourth NAND circuit 59.

Therefore, when switching to the automatic control as described above, the cutting height is outside the appropriate range set in the cutting height sensor 27, and the above-mentioned cutting part rising voltage signal vh or cutting lower voltage is output from the sensor 27. When the signal V1 is output, the first (7) NAND circuit 5 receives the signal vh.
4 is connected to the third NAND circuit 58 via the inverter 60, and the second NAND circuit 55 to which the signal V1 is input is connected to the fourth NAND circuit 59 via the inverter 61.
Since the reaping section rising voltage signal Vu
In the output state, the third NAND circuit 58 operates and outputs the rising voltage signal Vu, and in the output state of the reaping lower voltage signal v1, the fourth NAND circuit 59 operates and outputs the falling voltage signal Vd. .

The solenoid 18 or 19 is energized by this signal Vu or Vd, and the raising or lowering of the reaping part 2 is increased, but since the output pulse Pa of the monomulti 63 continues for t seconds. At this time, the mowing section 2 is raised or lowered continuously, and the mowing height can be quickly changed within the appropriate mowing 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 Pa output from the monomulti 63, so the mowing height sensor 27 detects the increased voltage at the cutting section. When the signal vh or the reaping lower voltage signal V1 is output, the first NAN
Pulse generation circuit 64 via D circuit 54 and inverter 60 or second NAND circuit 55 and inverter 61
In response to a signal input to the third NAN, the pulse generating circuit 64 generates an intermittent voltage pulse pb.
The signal is input to the D circuit 58 and the fourth NAND circuit 59.

Therefore, the first NAND circuit 54 is connected to the inverter 60
is connected to the third NAND circuit 58 via the second NAND circuit 58.
Since the D circuit 55 is connected to the fourth NAND circuit 59 via the inverter 61, in the output state of the reaping section increased voltage signal vh, the third NAND circuit 58 outputs the increased voltage signal Vu and the reaping section lower voltage signal Vh. In the output state of the voltage signal (1), the fourth NAND circuit 59 intermittently outputs the falling voltage signal Vd corresponding to each voltage pulse Pb.

The reaping section 2 is raised or lowered in stages 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 cutting height sensor 27 is present. As a result, the cutting height is controlled to be within the appropriate range.

As described above, the automatic control signal generation circuit section in the operation control circuit is connected to the input signal from the power supply side and the cutting height sensor 27.
The first circuit operates only for a certain period of time and outputs a continuous reaping section raising/lowering signal, and the second circuit operates in response to an input signal from the reaping section. It is configured with two types of circuits that output signals for raising and lowering the cutting height, and when switching to automatic control of the cutting height, the first
The continuous output signal of the second circuit quickly obtains the appropriate cutting height range, eliminating the cutting tendency at the start of mowing, and in steady state, the intermittent output signal of the second circuit allows the cutting height to be automatically controlled. This is to prevent hunting.

As shown in FIG. 5, switch 5 with automatic control
3. An automatic control indicator lamp 69 which has one terminal connected to the power circuit on the latter stage side, and whose other terminal is grounded through a resistor 70 and an NPN transistor 71 connected in parallel. The base of the transistor 71 is connected to the secondary side of the reaping latch interlocking switch 57 described above.

When the automatic control switch 53 is turned on, the transistor 69 is turned on by the input of the base signal from the secondary side of the reaping latch interlocking switch 57, so that the automatic control display lamp 69 is lit, indicating the automatic control state. Show that.

As described above, two NAND circuits 56a
, 56b are connected to each other.
A power supply circuit is connected to the input terminal of a, and a rising operation interlocking switch 49A and a lowering operation interlocking switch 50 are connected in parallel to each other.
A is connected to the inverter 72 via the inverter 72.

Further, the input terminal of the other NAND circuit 56b in the flip-flop 56 is connected to the above-mentioned interlocking switches 49A and 5.
0A - The next power supply circuit should be directly connected to supply voltage to the circuit section for automatic control as described above, but it should be connected directly to the power supply circuit connected to the NAND circuit 56b. Two automatic control return switches 73A, 73B and another reaping latch interlocking switch 57A are connected in parallel and inserted into the ground circuit.

Among the switches 49A, 50A, and 57A described above, the ascending operation interlocking switch 49A and the descending operation interlocking switch 5
As shown in the figure, 0A is linked with the above-mentioned raising operation switch 49 and lowering operation switch 50, and is raised by displacing the manual operation lever 48 shown in FIG. 6 in one direction along the arrow A. The operating switch 49 and the upward interlocking operation switch 49A are simultaneously turned on, and by displacing the manual operating lever 48 in the other direction along arrow A, the downward operating switch 50 and the downward operating interlocking switch 50A are simultaneously turned on. It is designed to be forced.

The other reaping latch interlocking switch 57A is interlocked with the reaping latch interlocking switch 57 as shown in the figure, but whereas the reaping latch interlocking switch 57 is turned on when the reaping latch is turned on as described above, The other reaping latch interlock switch 57A is configured as a switch that is turned on when the reaping latch is turned off.

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 Or the lowering operation switch 50 and the lowering operation interlocking switch 50
If A is turned on, the same manual control as described above is performed by operating the same lever 48, and the manual control state is maintained even though the automatic control switch 53 is turned on.

This is because the voltage signal of the power supply circuit is inverted by the inverter 72 and applied to the flip-flop 56 by turning on the rising operation interlocking switch 49A or the lowering operation interlocking switch 50A, so that the output from the flip-flop 56 disappears. This is also because, given the characteristics of flip-flops in general, a state in which no output is produced continues.

That is, the circuit section including the flip-flop 56 constitutes a manual control holding circuit that holds the manual control state, and when the holding circuit is in operation, the base signal of the transistor 71 disappears and the automatic control indicator lamp 69 lights up. disappear.

The function of the manual control holding circuit including the flip-flop 56 is released by grounding the input side of the holding circuit by once turning on the automatic control return switch 73A or 73B or another reaping latch interlocking switch 57A. Ru.

That is, these switches 73A, 73B, 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.
6 and 7, and is movable not only in the direction of the arrow A but also in the direction of the arrow B shown in FIGS. 6 and 7, which is perpendicular to the direction of the arrow A.

And the above-mentioned automatic control return switch 73A
, 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 73A However, when the automatic control return switch 73B is moved 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 to move the reaping section. 2, the operator rotates the machine after obtaining a slight rise, and then turns on the lowering operation switch 50 to lower the reaping section 2 again. By operating the lever 48 in one direction or the other along arrow B to turn on the automatic control return switch 73A or 73B, the automatic control state can be easily returned.

Returning to this automatic control state can also be performed by once turning off the reaping latch and then turning on the other reaping latch interlocking switch 57A.

When returning to automatic control, 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 latch interlocking switch 57, so unless the reaping latch is turned on and the interlocking switch 57 is turned on, the automatic control will not work. This means that the reaping section 2 cannot be raised or lowered due to this, so it is safe.

As shown in FIG. 6, the automatic control person switch 53 and the automatic control display lamp 69 described above 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 is clear from the above description, the cutting height adjustment device for a combine harvester of this invention manually 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 lowering the reaping section 2. Manual control by switching operation of operation switches 49 and 50 and cutting height sensor 27
A mowing height adjusting device is provided with an operation control circuit configured to selectively perform automatic control according to output signals vh and vl of
Manual switches 53 and 57 are provided for selectively connecting the automatic control signal generating circuit section of the operation control circuit to the power source 51 to put the automatic control signal generating circuit section into an operating state, and the automatic control signal generating circuit section The circuit section includes a continuous signal generating means 63 capable of generating a continuous signal only for a certain period of time after the manual switches 53 and 57 are turned on, and a pulse signal generator capable of generating a pulse signal when the manual switches 53 and 57 are turned on. means 64 are provided, and the above-mentioned signal generating means 63 and 64 are operated to generate signals by the signal input from the cutting height sensor 27, and the electromagnetic switching valve 10 is operated by the signals generated by the two signal generating means 63 and 64. The present invention is characterized in that the reaping section is moved up and down by being displaced to the lifting position.

Therefore, according to this invention, when the manual switch 53, 57 is turned on and the automatic control signal generating circuit section is in operation, the solenoid switching valve 10 is moved to the lifting position, that is, the reaping section is moved up and down by the continuous signal generating means 63. This is performed when the pulse signal generating means 64 performs a signal generating operation and when the pulse signal generating means 64 performs a signal generating operation.

Therefore, if the automatic control is entered by turning on the manual switches 53 and 57, and the steady state of automatic control are explained separately, the following effects will be obtained.

First, when the manual switch 53 or 57 is turned on to enter automatic control, the cutting height sensor 27 detects that the cutting section is not within the appropriate cutting height range and sends a signal requesting the raising or lowering of the cutting section. , both signal generating means 63 and 64 operate to generate signals.

In this case, the continuous signal generating means 63 is operated by the manual switch 53.
Since the continuous signal can be generated only for a certain period of time after the cutting height sensor 57 is turned on, the electromagnetic switching valve 10 will rise or fall only for the above certain period of time unless the signal output from the cutting height sensor 27 stops. The reaping section is continuously positioned in the operating position, and the reaping section is continuously raised or lowered for the same short period of time.

If the signal output from the cutting height sensor 27 continues after the same period of time has elapsed, that is, after the continuous signal generating means 63 has stopped operating, the pulse signal generated by the pulse signal generating means 64 will cause the electromagnetic switching valve to The position of the electromagnetic switching valve 10 is controlled by the pulse signal from the signal generating means 64, and the electromagnetic switching valve 10 is continuously or intermittently positioned in the raising or lowering position, and the reaping part is raised intermittently. Or it can be lowered.

Such raising and lowering of the reaping section is stopped when the reaping height sensor 27 detects the raising and lowering of the reaping section to the appropriate cutting height range and stops outputting a signal.

Therefore, when automatic control is entered, if the cutting section is far outside the proper cutting height range, it will be raised and lowered to the proper cutting height range continuously for a certain short period of time, and then intermittently. On the other hand, if the reaping section deviates from the appropriate cutting height range but the deviation is relatively small, the mowing portion will only be raised and lowered continuously to the appropriate cutting height range.

When automatic control is entered in this way, if the reaping section is not within the appropriate cutting height range, the reaping section will first be raised and lowered continuously in any case, so the reaping section will not be raised or lowered in the direction of the appropriate cutting height. This will be done quickly.

If the deviation from the appropriate cutting height range is small, the reaping part will only be raised and lowered continuously, but since the amount of elevation is small, the inertia is small and the reaping part will still have inertia even after reaching the appropriate cutting height range. If the cutting height does not rise or fall excessively, and on the other hand, there is a large deviation from the appropriate cutting height range, the amount of elevation of the cutting section will increase, but the lifting and lowering will continue intermittently during the final process, so the cutting section will This means that excessive lifting and lowering due to inertia will not occur.

Therefore, even though the mowing section can be quickly raised and lowered to the proper mowing height, a phenomenon such as shock does not occur.

In this regard, when a combine harvester is placed along the edge of a field in a field, the reaping section that has been raised significantly by manual control is lowered to the appropriate cutting height by automatic control after turning. Since the cutting part is lowered continuously for a certain period of time at the beginning, the lowering to the appropriate cutting height range is achieved relatively quickly, and at the end of the lowering process to the proper cutting height range. Since the reaping section is lowered intermittently, there is no possibility that the reaping section will descend excessively and its tip will plunge into the soil.

Therefore, the lowering of the reaping section is carried out relatively quickly, and the tendency of the reaping section to reap the culm at a high position is eliminated, and shocks that may damage the members are not generated.

Next, to explain the steady state of automatic control,
In this state, since the manual switches 53 and 57 are kept on, the continuous signal generating means 63 no longer operates.

Therefore, the displacement of the electromagnetic switching valve 10 to the elevating position, that is, the elevating and lowering of the reaping section, is performed by the pulse signal generating means 64.
This is done only by the pulse signal generated by the cutting section, and when the cutting section is out of the appropriate cutting height range, the raising and lowering of the cutting section is done intermittently, that is, gradually.

As a result, not only is there no shock caused by sudden elevation of the cutting section, but also the cutting height sensor repeats the rising and falling signals when it hits a soft part or dent in the field, or climbs onto a clod or stump. When this occurs, the reaping section may repeatedly rise and fall in a hunting manner, or in other words, the reaping section may be raised and lowered in a hunting manner due to a very short and transient sensor signal. Since there is an interval (pulse generator stop time) between the signals generated by the pulse signal generating means 64, this is eliminated, and the mowing height is controlled stably and accurately, so that no defective mowing occurs.

[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. FIG. 5 is a circuit diagram of an operation control circuit in the same embodiment. FIG. 6 is a perspective view of a part of the combine harvester. FIG. 7 is a part shown in FIG. 6. FIG. 2...Reaping section, 9...Hydraulic lift cylinder, 10...Solenoid switching valve, 18, 19...
...Solenoid, 27...Mowing height sensor,
28...Sensor arm, 29...Arm axis, 30---Photo interrupter, 30
a... Notch groove, 31, 32... Support frame, 33A, 34A... Light emitting diode, 33
B, 34B...Photo transistor, 44,
45...Transistor, 46.47...
・Transistor, 48...Manual operation lever, 4
9... Ascend operation switch, 50... Descend operation switch, 53... Automatic control switch, 54, 55... NAND circuit, 5
6...Flip-flop, 58°59...
...NAND circuit, 60.61 ...Inverter, 62 ... Differentiation circuit, 63 ... Monomulti, 64 ... Pulse generation circuit, 69 ...・・・
・・Automatic control display lamp, 73A, 73B・・
...Automatic control return switch.

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. A mowing height adjusting device comprising an operation control circuit configured to selectively perform one of the mowing heights,
Manual switches 53 and 57 are provided for selectively connecting the automatic control signal generating circuit section of the operation control circuit to the power source 51 to put the automatic control signal generating circuit section into an operating state, and the automatic control signal generating circuit section The circuit section includes a continuous signal generating means 63 that can generate a continuous signal for a certain period of time after the manual switch 53.57 is turned on, and a pulse signal generator that can generate a pulse signal when the manual switch 53.57 is on. means 64 are provided, and the above-mentioned signal generating means 63 and 64 are operated to generate a signal in response to a signal input from the cutting height sensor 27, and the electromagnetic switching valve 10 is raised and lowered by the generated signals of both signal generating means 63 and 64. A cutting height adjusting device for a combine harvester, characterized in that the cutting height adjusting device for a combine harvester is configured to move the cutting portion to an operating position and raise and lower the cutting portion.