JPS6140095Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a combine harvester that reaps grain culms in a field and threshes the harvested grain culms, by raising and lowering the reaping part in response to a signal from a cutting height sensor. The present invention relates to a cutting height adjustment device that adjusts the cutting height of grain culms.

Conventional technology and its problems A technology for adjusting the cutting height by selectively driving the solenoid of the solenoid valve for raising and lowering the cutting section in accordance with a signal from a cutting height sensor in a combine harvester is disclosed, for example, in Japanese Patent Laid-Open No. 52-34226. It is already known as disclosed in Japanese Patent Application Laid-Open No. 52-47422, Japanese Patent Application Laid-Open No. 52-47428, and Japanese Utility Model Application Publication No. 54-14927.

However, with conventional models, the solenoid valve solenoid was driven continuously as long as the cutting height sensor was generating a rising or falling signal, so the cutting section was frequently raised and lowered in a hunting manner, and the cutting Sudden and excessive rise and fall of the parts were likely to occur. This phenomenon makes the control of the cutting height unstable and causes problems with poor cutting, and if the cutting part descends suddenly or excessively due to inertia, the tip of the cutting part will plunge into the soil and cause a shock. damage to parts is likely to occur.

Next, it is well known that the reaping section is raised and lowered in conjunction with the cutting of the reaping clutch, but among the four publications mentioned above, Japanese Patent Application Laid-open No. 52-47422 discloses that when the reaping clutch is engaged, the reaping section is raised and lowered to a certain height on the ground. A technique is disclosed in which a reaping clutch is associated with a reaping height adjustment device such that the reaping clutch can be lowered. According to this conventional technology, when the combine harvester is rotated at the end of the field and the next row is to be harvested, the reaping clutch that was disengaged at the time of rotation is engaged, and the reaping unit is lowered to the reaping position, which simplifies the operation. However, the lowering of the reaping unit in conjunction with the engagement of the reaping clutch is supposed to be carried out to a certain height on the ground detected by the cutting height sensor, so the lowering of the reaping unit is performed continuously from a high raised position. There is a problem in that the reaping section, which is descending automatically, descends excessively due to inertia past the height detected by the sensor, and the tip of the reaping section plunges into the soil.

The purpose of this invention is to control the cutting height stably and accurately to eliminate damage to parts and poor cutting, and to simplify operation and heighten the height by lowering the cutting part continuously when the cutting clutch is engaged. An object of the present invention is to provide a new cutting height adjustment device for a combine harvester that improves work efficiency while ensuring safety by preventing excessive lowering of the cutting section when the cutting clutch is engaged.

Technical means for solving the problems In order to solve the above-mentioned problems of the invention, this invention took the following technical measures.

In other words, this idea, as illustrated in Figure 1,
A mowing height sensor 27 that detects a deviation of the mowing height from the appropriate range and generates signals for raising and lowering the mowing section.
In a combine harvester equipped with a reaping clutch, there is provided a reaping interlock switch 57 which is turned off when the reaping clutch is disengaged and turned on when the reaping clutch is engaged.
, a continuous signal generating means 63 capable of generating a continuous signal only for a certain period of time after the reaping interlocking switch 57 is turned on, and a pulse signal generating means 64 capable of generating an intermittent pulse signal when the reaping interlocking switch 57 is on. and solenoid driving means 44, 45 which operate when at least one of the signal generating means 63, 64 generates a signal. The solenoid driving means 44 and 45 drive the solenoids 18 and 19 of the solenoid valves for raising and lowering the reaping section by generating a signal in response to a signal input from the cutting height sensor 27.

Therefore, according to this invention, when the reaping clutch is engaged and the reaping interlocking switch 57 is turned on, if the reaping height sensor 27 is generating a signal for raising or lowering the reaping section at that time, a continuous signal is generated afterwards. The generating means 63 generates a continuous signal Pa for a certain period of time (t seconds).
As long as the reaping clutch is engaged and the reaping interlock switch 57 is on, the pulse signal generating means 64 generates an intermittent pulse signal when the reaping height sensor 27 generates a signal to raise or lower the reaping section.
In order to generate Pb, the solenoid valve solenoids 18 and 19 are driven by the solenoid drive means 44 and 45 when at least one of the two types of signals Pa and Pb is generated. and raise/lower the reaping section. When both signals Pa and Pb are generated, the solenoid drive means 44 and 45 are operated continuously by the continuous signal Pa, so as long as the same signal Pa is generated, the solenoid valve solenoids 18 and 19 are operated continuously. are driven continuously, and if the pulse signal Pb is still generated even when the continuous signal Pa is no longer generated, the solenoid drive means 44 and 45 operate intermittently in response to the solenoid valve solenoids 18 and 19. is driven intermittently or intermittently.

Therefore, when the combine harvester is rotated at the end of the field and the next row is to be harvested, if the reaping clutch that was disengaged during rotation is engaged, the cutting height sensor 27 will output a descending signal Vl. After the reaping interlocking switch 57 is turned on, the lowering solenoid 19 is continuously driven by the continuous signal Pa generated by the continuous signal generating means 63 for t seconds, and thereafter, as long as the lowering signal Vl continues, the lowering solenoid 19 is driven by the pulse signal. It is intermittently driven by the pulse signal Pb generated by the generating means 64. Therefore, if the above-mentioned time t is set appropriately, the cutting section will be lowered rapidly to a position slightly higher than the lower limit position detected by the cutting height sensor 27, and then the cutting section will be lowered rapidly in response to the pulse signal Pb. The reaping section is slowly lowered by intermittent driving of the solenoid 19, and the reaping section does not descend excessively.

Also, in the steady state of cutting work, the cutting height sensor 2
7 detects a deviation of the cutting height from the appropriate range and generates a rising or falling signal, the pulse signal generating means 64 generates a pulse signal Pb and the raising solenoid 18 or lowering solenoid 19 is activated intermittently. The reaping section is moved slowly upwards or downwards accordingly. For this reason, the reaping section does not move up and down suddenly or excessively, nor does it repeatedly rise and fall like hunting.

Embodiment Combine Harvester Structure The illustrated embodiment relates to an example in which this invention is implemented in a combine harvester as shown in FIG.

The combine harvester shown in FIG. 2 divides planted grain culms using a divider 3 at the lower front end of a reaping section 2 at the front of the machine while moving the machine by driving a crawler 1. The planted grain culm is raised by the cutting device 4, the planted grain culm is harvested at the base of the stock by the cutting blade 5, and the cut grain culm is conveyed toward the threshing part 7 by the vertical conveyance belt 6, The feed chain 8 on one side of the threshing section 7 transports the harvested grain culm rearward and feeds the tip side of the grain culm into the threshing section 7 for threshing.

Hydraulic Mechanism The above-mentioned reaping section 2 is supported so as to be movable up and down as usual, and the up and down movement of the reaping section 2 is carried out by a single-acting hydraulic lift cylinder 9 shown in FIG.

In order to control the operation of the hydraulic lift cylinder 9, a solenoid valve 10 shown in FIG. 3 is provided. This electromagnetic valve 10 includes an oil supply circuit 14 that guides hydraulic oil at a pressure set by a pressure regulating valve 13 from an oil tank 11 by a hydraulic pump 12 toward a hydraulic lift cylinder 9, and an oil supply circuit 14 that guides hydraulic oil at a hydraulic pressure set by a pressure regulating valve 13 from an oil tank 11 toward the hydraulic lift cylinder 9, and from the hydraulic lift cylinder 9 toward the oil tank 11. The primary side is connected to an oil drain circuit 15 that discharges hydraulic oil. The solenoid valve 10 is
As shown in the figure, the connection circuit 16 connecting 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 extension/retraction position, and the oil supply circuit 14 is connected as described above. A lifting action position U that connects to the circuit 16 to supply hydraulic oil to the hydraulic lift cylinder 9 and causes the cylinder 9 to extend and raise the reaping part 2, and connects the connection circuit 16 to the oil drain circuit 15 Connect hydraulic lift cylinder 9
A lowering action position D is provided to allow oil to be drained from the lower part and to allow the reaping part 2 to descend by its own weight. The connection circuit 16 described above includes a hydraulic lift cylinder 9
A slow return valve 17 is inserted, which is formed by connecting a check valve 17a and a variable throttle 17b in parallel, which allow only oil flow in this direction. The solenoid valve 10 is displaced from the neutral position N shown in the figure to the upward operating position U by energizing the solenoid 18 and to the descending operating position D by energizing the solenoid 19, respectively.

In the illustrated case, the vertical conveyance belt 6 is of a double-acting type for changing the posture so that the position of the grain culm joining end of the conveyance belt 6 to the feed chain 8 is changed according to the length of the harvested grain culm. Hydraulic oil is also supplied to the vertical conveyance adjustment cylinder 20 by the same hydraulic system. That is, as similarly shown in FIG. The solenoid valve 10 is configured such that the oil supply circuit 14 is connected to the oil supply circuit 21 at the position N and the downward action position D.
It consists of Then, the above-mentioned oil supply circuit 21
and another oil drain circuit 22 connected to the oil drain circuit 15, and the vertical conveyance adjustment cylinder 2.
0 expansion oil chamber 20a and contraction oil chamber 20b
The other solenoid valves 23 each have a secondary side connected to
However, it is provided. As shown in the figure, the other solenoid valve 23 connects the oil supply circuit 21 and the oil drain circuit 22, blocks both secondary ports, and maintains the vertical conveyance adjustment cylinder 20 at a constant extension/retraction position at the neutral position N. and the oil supply circuit 21 is connected to the extension oil chamber 2 described above.
0a and the above-mentioned reduction oil chamber 20b.
is connected to the oil drain circuit 22 to extend the vertical conveyance adjustment cylinder 20, and the oil supply circuit 21 is connected to the contraction chamber 20b and the extension oil chamber 20a is moved to the oil drain circuit. 22 and a reduction operation position for causing the vertical conveyance adjustment cylinder 20 to perform a reduction operation. In FIG. 3, 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 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.

Sensor Mechanism As shown in FIGS. 2 and 4, 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 32a sandwiching the outer peripheral edge of this photointerrupter 30,
Two support frames 31 and 32 with support frames 32b are fixedly installed within the cutting height sensor 27 with an appropriate circumferential spacing between them. Each support frame 31, 3
One of the leg plates 31a and 32a of 2 is equipped with light emitting diodes 33A and 34A shown in FIG. 1, and the other leg plate 31b and 32b are equipped with photo transistors 33B and 34B shown in FIG. 1, respectively. These light emitting diodes 33A, 34A and photo transistors 33B, 34B are connected in parallel as shown in FIG. 1, with one end connected to a power supply terminal and the other end grounded.

The cutting height sensor 27 rotates up and down while the sensor arm 28 is in sliding contact with the field surface, and the arm shaft 29 and the photointerrupter 30 mounted thereon are rotated and displaced, and the photointerrupter 30 detects the cutting height of the photointerrupter 30.
When the notched groove 30a of the support frame 30 reaches the position of each of the support frames 31 and 32, light from the light emitting diodes 33A and 34A on the support frames 31 and 32 is incident on each of the support frames 31 and 32.
Phototransistors 33B, 34 on 1, 32
The light emitting diode 33A and phototransistor 33B on the support frame 31 detect the lower limit of the appropriate mowing height range, and the light emitting diode 34A and phototransistor 34B on the support frame 32 detect the upper limit of the appropriate mowing height range.
The output circuit leading from the emitter of the phototransistor 33B receives a reaper rise voltage signal Vh, and the output circuit leading from the emitter of the phototransistor 34B receives a reaper fall voltage signal Vl.
Each of them is selectively output.

As shown in FIG. 4, 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 (second
(Figure) The bell crank 36 is guided to a nearby cutting height set lever 40, and by displacing the cutting height set lever 40 in the direction of the arrow, the bell crank 36 is rotated, and the cutting height sensor 27 is moved up and down. It is possible to adjust the position and set the cutting height to the cutting height sensor 27 according to the crop condition, field conditions, etc. In FIG. 4, reference numeral 41 denotes a lock plate that releasably locks the cutting height set lever 40.

Operation Control Circuit and Its Function The control of changing the position of the solenoid valve 10 shown in FIG. 3 and previously described is effected by the operation control circuit shown in FIG.

As shown in FIG. 1, the solenoids 18 and 19 of the solenoid valve 10 are connected in parallel with surge absorbing 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 grounding circuit of each solenoid 18, 19, the emitter is grounded.
NPN transistors 44 and 45 are inserted,
Other NPN transistors 46 and 47 whose collectors are connected to the bases of these transistors 44 and 45 and whose emitters are grounded are provided. The collectors and bases of each of the transistors 46 and 47 mentioned above are connected to a power supply terminal, respectively, and the bases of each of the other transistors 46 and 47 are connected to each other by a manual operation lever 48 shown in FIG. It is grounded via a raising operation switch 49 or a lowering operation switch 50 which are selectively turned on. In FIG. 1, 51 is a battery constituting a power source, and 52 is a main switch that connects and disconnects the battery 51 from the entire illustrated control circuit.

In the operation control circuit shown in Fig. 1, 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 lowering 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, no voltage signal is input to the base, and the transistor 47 is turned off. A base signal is input from the power supply side to the transistor 45 whose base is connected to the base of the transistor 45.
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 solenoid valve 10 shown in FIG. Moved to D. 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. By raising and lowering the section 2, 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 Figure 1.
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 interlock switch 57 that is turned on when the reaping clutch is engaged, and the first
The input terminal of the NAND circuit 54 is further provided with the photo signal.
The output circuit of transistor 33B is the second NAND
Further, the output circuits of the photo transistors 34B are connected to the input terminals of the circuits 55, respectively. Further, the output terminal is connected to the transistors 46 and 4.
Third and fourth NAND circuits 58 and 59 are respectively connected to the base of 7, and the input terminals of these third and fourth NAND circuits 58 and 59 are connected to second NAND circuit 54,
The output end of 55 passes through inverters 60 and 61,
each connected. Further, the differential circuit 62 is connected to the power supply circuit led through the flip-flop 56 and the reaping interlock switch 57 described above.
In addition, a continuous signal generating means (mono-multi) 63 is provided connected to the differentiating circuit 62 and the power supply circuit via the flip-flop 56 and the reaping interlocking switch 57, and a pulse signal generating means (pulse generating circuit) 64 is provided. The generating means 64 is connected to the output ends of both inverters 60 and 61 whose input ends are described above.
Diode 6 that allows signal transmission only in the direction
5 and 66. The output end of the continuous signal generation means 63 and the output end of the pulse signal generation means 64 are connected to a third NAND circuit 58 and a fourth NAND circuit 59, respectively.
They are connected via diodes 67 and 68 that allow signal transmission only in the direction of NAND circuits 58 and 59. The continuous signal generating means 63 described above is equipped with a timer integrating circuit 63a as shown in the figure.
Flip-flop 56 and reaping interlock switch 57
It operates by instantaneously dropping the power supply voltage Vcc led through the voltage below a certain voltage, and generates a rectangular voltage pulse Pa that lasts for t seconds. The above-mentioned differentiating circuit 62 on the preceding stage side of the continuous signal generating means 63
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, a diode 62c that cuts off the differential pulse when there is no input signal from the power supply side, and It is equipped with a capacitor 62d that instantaneously drops the power supply voltage upon receiving the differential pulse, and triggers the continuous signal generation means 63 to generate the pulse Pa when a signal from the power supply side is input. do. Further, the pulse signal generating means 64 includes a NAND circuit 64
It has a conventional configuration as a pulse generating circuit, which includes an inverter 64b, a capacitor 64c, and a resistor connected as shown in the figure, and generates intermittent voltage pulses Pb in response to an input signal.

Here, obtained from the circuit configuration explained above,
To explain the function of the automatic control of the cutting height, when the automatic control is performed by turning on the automatic control switch 53 and the reaping interlocking switch 57, the raising operation switch 49 and the lowering operation switch 5 are activated during manual control.
In place of the selective ON operation of 0, the increased voltage signal Vu selectively output from the third NAND circuit 58
and the increased voltage signal Vd selectively output from the fourth NAND circuit 59, the solenoid 18,
19 is selectively energized. Considering the circuit configuration described above, each of the above-mentioned rising voltage signal Vu and falling voltage signal Vd is the above-mentioned rising voltage signal of each reaping section.
Vh, low (L) when the reaping section falling voltage signal Vl is output
Each signal Vu, Vd is output as a level signal.
The output of the third and fourth NAND circuits 58 and 5
Since the output end side of 9 is grounded, when these signals Vu and Vd are selectively output, each
The transistors 46 and 47 whose bases are connected to the output terminals of the NAND circuits 58 and 59 are selectively turned off, and therefore each transistor 4
4 and 45 are selectively turned on, thereby selectively energizing the respective solenoids 18 and 19, so that the solenoid valve 10 shown in FIG. It is displaced to position D.

First, we will explain the effect when the automatic control switch 53 and the reaping interlocking switch 57 are turned on to switch to the automatic control state of the cutting height. The circuit 62 is activated to trigger the continuous signal generating means 63 to generate said voltage pulse Pa for t seconds (e.g. 5-10 seconds);
This voltage pulse is applied to the third NAND circuit 58 and the fourth NAND circuit 58.
is input to the NAND circuit 59. Therefore,
When switching to 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 section rising voltage signal Vh or cutting section falling voltage signal Vl is output from the sensor 27. is output, the first input signal Vh is output.
The NAND circuit 54 connects the third
Since the second NAND circuit 55, which is connected to the NAND circuit 58 and receives the signal Vl, is connected to the fourth NAND circuit 59 via the inverter 61, the output state of the reaping section rising voltage signal Vh is Then, the third NAND circuit 58 operates to generate a rising voltage signal.
Vu is output, and in the output state of the reaping section falling voltage signal Vl, the fourth NAND circuit 59 operates to output a falling voltage signal Vd. This signal Vu or Vd excites the solenoid 18 or 19 to raise or lower the reaping section 2, and the output pulse Pa of the continuous signal generating means 63 continues for t seconds. Therefore, the mowing section 2 is raised or lowered continuously at this time, 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 continuous signal generating means 63, so the cutting height sensor 2
When the reaping section rising voltage signal Vh or the reaping section falling voltage signal Vl is output from 7, the first NAND circuit 54
By inputting a signal to the pulse signal generating means 64 through the inverter 60 or the second NAND circuit 55 and the inverter 61, the pulse signal generating means 64 generates an intermittent voltage pulse Pb. The signal is input to the No. 3 NAND circuit 58 and the fourth NAND circuit 59. Therefore, the first
The NAND circuit 54 connects the third
A second NAND circuit 55 connected to the NAND circuit 58
is connected to the fourth NAND circuit 59 via the inverter 61, the reaping section rising voltage signal
In the output state of Vh, the third NAND circuit 58 outputs the rising voltage signal Vu, and in the output state of the reaping part falling voltage signal Vl, the fourth NAND circuit 59 outputs the falling voltage signal.
Vd is intermittently output in correspondence with each voltage pulse Pb. An intermittent output signal from the NAND circuit 58 or 59 that is continuously output as long as the output signal Vh or Vl from the cutting height sensor 27 is present.
Depending on Vu or Vd, the reaping section 2 is raised or lowered in stages, and the reaping height is controlled to be within an appropriate range. In this way, by raising and lowering the reaping section 2 in stages under the steady state of automatic control, it is possible to avoid unexpected excessive lifting and lowering of the reaping section 2 or the occurrence of shocks when the reaping section 2 is raised and lowered continuously. .

As shown in FIG. 1, it is an automatic control indicator lamp 69 having one terminal connected to the power circuit on the downstream side of the automatic control switch 53.
An automatic control indicator lamp 69 whose other terminal is grounded through a resistor 70 and an NPN transistor 71 connected in parallel is provided, and the base of the transistor 71 is connected to the secondary side of the reaping interlock switch 57. It's connected. The automatic control display lamp 69 indicates that when the automatic control switch 53 is turned on, the reaping interlock switch 5
7. Since the transistor 69 is turned on by the input of the base signal from the secondary side, it is lit to indicate that it is in an automatic control state.

In the flip-flop 56, which is formed by interconnecting the input ends and output ends of two NAND circuits 56a and 56b, a power supply circuit is connected to the input end of one of the NAND circuits 56a. The switch 49A and the lowering operation interlocking switch 50A are connected via an inverter 72. Also, the other side of the flip-flop 56
The input terminal of the NAND circuit 56b is directly connected to the power supply circuit of the primary side of both the interlocking switches 49A and 50A described above, in order to supply voltage to the circuit section for automatic control as described above. However, the grounding circuit branched from the power supply circuit connected to the NAND circuit 56b has an emitter grounding.
The NPN transistor 73 and another reaping interlock switch 57A are inserted and connected in parallel.
Of the switches 49A, 50A, and 57A described above, 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 FIG. By displacing the manual operation lever 48 shown in the arrow A in one direction, the raising operation switch 49 and the raising operation interlocking switch 49A are simultaneously turned on, and the manual operation lever 48 is turned on in the other direction along the arrow A. The lowering operation switch 50 and the lowering operation interlocking switch 50A are simultaneously turned on by the displacement operation. The other reaping interlocking switch 57A is interlocked with the reaping interlocking switch 57 as shown in the figure, but whereas the reaping interlocking switch 57 is turned on when the reaping clutch is engaged as described above, The interlocking switch 57A is configured as a switch that is turned on when the reaping clutch is disengaged.

Based on the above, when the automatic control switch 53 and the reaping interlocking switch 57 are on, the manual operation lever 4
8 in the direction of arrow A in FIG.
If A or the lowering operation switch 50 and the lowering operation interlocking switch 50A are turned on, the same lever 4
Not only is the same manual control as described above performed by the 8 operation, but 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 raising operation interlocking switch 49A or the lowering operation interlocking switch 50A, so that the output from the flip-flop 56 disappears and the flip-flop This is because, in view of the general characteristics, a state without the same output continues. That is, the circuit section including the flip-flop 56 constitutes a manual control holding circuit that holds the manual control state, and in the operating state of the holding circuit, the transistor 7
1 base signal disappears, the automatic control display lamp 69 goes out. flip flop 56
The function of the manual control holding circuit including the holding circuit is to turn on the input side of the holding circuit once by turning on the transistor 73 or other reaping interlocking switch 57A.
If you ground it, it will be released. That is, these transistors 73 and switch 57A are provided for the purpose of canceling the function.

As shown in FIG. 1, an automatic control return switch 74 is provided with one end connected to the power supply circuit and the other end grounded, and the power supply circuit is connected to the base of the transistor 73 through this return switch 74. By connecting the automatic control return switch 74 and turning on the automatic control return switch 74, a voltage signal can be applied from the power supply circuit to the base of the transistor 73, and the transistor 73 can be turned on. The automatic control return switch 74 mentioned above is particularly a photoelectric switch 74, which is an example of a non-contact switch, and is turned on when its light receiving section is covered with a hand or the like. FIG. 6 shows an operating section provided near the operator's seat 39 of the illustrated combine harvester.
4 is disposed on the operating section.

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 reaping section 2 is raised slightly and then rotated, and then the lowering operation switch 50 is turned on to lower the reaping section 2 again, the operator must use the automatic control return switch to turn the reaping section 2 down again. Without checking a certain photoelectric switch 74 with a glance,
For example, even while looking ahead, the driver can easily return to the automatic control state by bringing his hand near the photoelectric switch 74 to turn on the switch 74. Returning to this automatic control state can also be performed by once disengaging the reaping clutch and then turning on the other reaping interlock 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. Since the power supply circuit is connected to the circuit for automatic control via the reaping interlock switch 57, the reaping section 2 cannot be raised or lowered under automatic control unless the reaping clutch is engaged and the interlock switch 57 is turned on. I can't.

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 75 for changing the vehicle speed of the illustrated combine harvester and other operating members.

Effects of the invention As mentioned above, this invention operates when at least one of the signals Pa and Pb is generated by a combination of a continuous signal Pa that lasts for a certain period of time and an intermittent pulse signal Pb. Solenoid valve solenoid 1 via solenoid drive means 44, 45
8 and 19, and these signals
Pa and Pb are the cutting clutch and cutting height sensor 27
It is assumed that this will occur in connection with. In particular, the continuous signal generating means 63 that generates the continuous signal Pa can generate signals only for a certain period of time after the reaping clutch is engaged and the reaping interlocking switch 57 is turned on, and the pulse signal generating means that generates the pulse signal Pb 64 is the reaping interlock switch 5
These signal generating means 63 and 64 are connected to the cutting height sensor 2, which can generate a signal when the signal generator 7 is on.
It is assumed to be operated by signal input from 7.

Therefore, according to this invention, when the reaping clutch is engaged and the reaping operation is performed normally, the solenoid valve solenoids 18 and 19 are operated intermittently by the pulse signal Pb in accordance with the signal output of the reaping height sensor 27. driven in stages or in stages. For this reason, the reaping section is gradually and slowly displaced in the direction commanded by the cutting height sensor 27, and therefore does not move up or down excessively due to inertia beyond that commanded by the cutting height sensor 27. In other words, stable and highly accurate cutting height control is performed, and problems such as the tip of the cutting section sticking into the soil do not occur, and defects such as poor cutting and damage to members are eliminated.

Also, when the reaping clutch is engaged, the solenoid valve solenoids 18 and 19 first send a continuous signal for a certain period of time.
Since it is driven by Pa, when the reaping clutch is disengaged, the combine is rotated, and the reaping clutch is engaged for reaping the next row, the reaping section will continue to move rapidly for the above-mentioned period of time. The cutting part can be lowered and then slowly lowered to a predetermined position commanded by the cutting height sensor 27 by driving a solenoid using the pulse signal Pb, and the cutting part can be lowered in a relatively short time without excessive lowering. As a result, it is possible to avoid excessive lowering due to continuous lowering from a high position while maintaining the advantages of simple operation and high work efficiency due to relatively quick lowering linked to the reaping clutch. Ensure safety to prevent damage to the cutting section.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an operation control circuit according to an embodiment of this invention, Fig. 2 is a perspective view of a combine harvester equipped with the same embodiment, Fig. 3 is a circuit diagram of a hydraulic circuit in the combine, and Fig. 4 is a schematic diagram of an operation control circuit according to an embodiment of the invention. FIG. 5 is a perspective view showing the main parts of the same embodiment. FIG. 5 is a perspective view of the main parts of the same embodiment.
The figure is a perspective view showing a part of the combine harvester. 2...Reaping section, 9...Hydraulic lift cylinder, 1
0... Solenoid valve, 18, 19... Solenoid, 27
...Mowing height sensor, 28...Sensor arm,
29... Arm shaft, 30... Photo interactor, 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, 54,55...
NAND circuit, 57... Reaping interlock switch, 58,
59...NAND circuit, 62...Differential circuit, 63...
... Continuous signal generating means, 64... Pulse signal generating means.

Claims (1)

[Scope of utility model registration request] A cutting height sensor 2 that detects a deviation of the cutting height from the appropriate range and generates signals for raising and lowering the cutting section.
7, a reaping interlocking switch 57 that is linked to the reaping clutch disengagement and turns off when the reaping clutch is disengaged and turns on when the reaping clutch is engaged.
, a continuous signal generating means 63 capable of generating a continuous signal only for a certain period of time after the reaping interlocking switch 57 is turned on, and a pulse signal generating means 64 capable of generating an intermittent pulse signal when the reaping interlocking switch 57 is on. and solenoid driving means 44, 45 which operate when at least one of the signal generating means 63, 64 generates a signal. The mowing height adjustment of the combine is configured such that a signal is generated in response to a signal input from the mowing height sensor 27, and the solenoids 18 and 19 of a solenoid valve for raising and lowering the mowing section are driven by the solenoid drive means 44 and 45. Device.