JPS6216603B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a ground work device mounted on a tractor so as to be able to rise and fall is provided with a sensor that detects the work depth based on the amount of vertical movement of the ground follower, and the detected work depth is determined by a setting device. The present invention relates to an automatic lifting control mechanism for a ground working device configured to automatically lift and lower the ground working device based on a detection result by a sensor so that the working depth is equal to a given set working depth.

In the above control mechanism, in order to lower the ground work equipment as quickly as possible to the set work depth after it has been raised into the air, the ground work equipment is rapidly raised to a level a certain distance above the set work depth. After that, it was lowered slowly, and during control, it was raised and lowered slowly to stabilize the control. However, if the working depth setting is changed or the amount of subsidence of the tractor itself changes, the ground level at which slow descent starts will change, and if the slow descent start level is higher than the ground, the setting work will be difficult. It took time to reach the depth, and when the slow descent start level was below the ground, the ground work equipment was rapidly plunged into the ground, causing a large shock and sudden load.

The present invention aims to solve such problems.

Embodiments of the present invention will be described below based on illustrative drawings.

FIG. 1 shows a side view of a riding-type tiller, in which a rotary tiller 2, which is an example of a ground work device, is connected to the rear of a tractor 1 via a lift arm 3 so as to be movable up and down. The lift arm 3 is driven by a single-acting hydraulic cylinder 4, and an electromagnetic switching valve 5 for controlling the cylinder 4 is connected to a control circuit shown in FIG. 4.

In the figure, reference numeral 6 denotes a variable resistor as a setting device for defining the target work level (depth of plowing), which is provided near the control section of the tractor 1 and can be changed and adjusted as desired. 7 is a potentiometer as a working depth detection sensor, and is connected to the rear cover 8 of the tilling device 2.
is used as a ground follower, and the output changes depending on the amount of vertical swing. Reference numeral 9 is a subtraction circuit that calculates the difference between the setting signal from the setting device 6 and the detection signal from the sensor 7, and the deviation amount of the detected working depth from the set working depth is extracted here. Reference numeral 10 denotes a rise determination circuit that compares the output signal from the subtraction circuit 9 with the rise reference signal; 11 is a similar fall determination circuit;
Based on the deviation from the set working depth, it is determined whether raising, lowering, or maintaining neutrality is necessary. 12 is a rising current amplification circuit connected to the rising discrimination circuit 10; 13 is a falling current amplifying circuit connected to the falling discrimination circuit 11; outputs from the rising or falling discrimination circuits 10 and 11; , and the upward excitation section 14 or the downward excitation section 15 of the electromagnetic switching valve 5 is driven. Further, 16 directly activates the rising current amplifying circuit 12 by closing, and
This is a switch for forced ascent that checks the operation of the descending current amplification circuit 13, and is provided near the control section.

The above configuration is not particularly different from the conventional one,
The tillage depth is stabilized by controlling the up-and-down movement of the tilling device 2 so as to balance the detection signal of the sensor 7 with the setting signal.

In addition to the basic configuration described above, the present invention incorporates the following circuit.

That is, the detection signal from the sensor 7 is compared with the reference signal given by the first setter 17a in the first comparison circuit 18a, and when the detection level is lower than the set level, that is, when the rear cover 8 is When it is oscillated upward, it is configured to start the first intermittent signal generation circuit 19a connected to the first comparison circuit 18a, and this intermittent signal generation circuit 1
9a is connected to the descending current amplification circuit 13. Therefore, if a descending signal is continuously issued from the descending determination circuit 11 while the intermittent signal generation circuit 19a is activated, the valve drive is intermittently inhibited by the intermittent signal, and as a result, the tilling device 2 is intermittently inhibited. It is lowered at a slow speed.

The first setting device 17a is adjusted in advance so that the detection level for activating the intermittent signal generation circuit 19a corresponds to the level at which the lower end of the tilling device 2 contacts the ground.

Further, the detection signal from the sensor 7 is further compared with respective reference signals given by the second setting device 17b and the third setting device 17c by the second comparison circuit 18b and the third comparison circuit 18c. The second setter 17b sets a relatively shallow plowing depth (for example, 5 cm).
At the same time, the third setter 17c sets a reference signal corresponding to a certain plowing depth (for example, 10 cm) that is deeper than this, and the second and third comparators 18b and 18c are connected to a second intermittent signal generation circuit 19b and a third intermittent signal generation circuit 19c, respectively.

Then, from the first intermittent signal generation circuit 19a, for example, an ON time (lowering permission time) of 30 msec,
An intermittent signal with an OFF time (down prohibition time) of 150 msec is output, and an intermittent signal with an ON time of 20 msec and an OFF time of 150 msec is output from the second intermittent signal generating circuit 19b, and furthermore, a third intermittent signal generating circuit 19c
For example, ON time is 10msec, OFF time is 150m.
It is set to emit an intermittent signal of sec.

In other words, the descent in the air is a continuous rapid descent, and the plowing depth is 5 cm from the ground surface, which is the first reference level.
Until then, the plowing depth was 5cm to 10cm, with intermittent slow descent.
cm, a slower intermittent lowering with a shorter permitted lowering time than the above-mentioned intermittent lowering is set, and at a plowing depth of 10 cm or more, an even slower intermittent lowering with a shorter permitted lowering time is set.

Therefore, after completing one stroke of tilling, the tilling device 2 is raised to the upper limit by operating the switch 16 to change the direction of the machine.
6 and move forward while lowering the tilling device 2. In this case, the descending region until the tilling device 2 touches the ground is a rapid descent due to continuous descent, and after that the descending region at the set plowing depth. In this case, there is a slow descent due to intermittent descent, and furthermore, in this slow descent region, the descent speed (absolute speed is constant) gradually decreases as the depth increases. However, in the embodiment described above, when the set plowing depth is 10 cm or more, the intermittent lowering speed changes in three stages, but if the set plowing depth becomes shallower, the slow lowering speed becomes two stages or only one stage.

Incidentally, it is preferable to make each of the setting devices 17a, 17b, and 17c adjustable so that the descending speed change level can be adjusted as desired. In addition, for intermittent slow descent at each stage, it is also possible to set intermittent signals with the same period with different ON times (lowering permission time), or with the same ON time (lowering permission time).
Intermittent signals with different OFF times may be set and used. Furthermore, if the absolute descending speed of the lift arm 3 can be changed using an electromagnetic variable throttle valve or the like, it becomes possible to perform speed control with continuous descending in the entire descending range. It goes without saying that if a large number of setters 17b are provided, the speed can be changed in even more steps, but it is also possible to continuously proportionally control the descending speed in accordance with the detected plowing depth. Also, sensor 7
It is also conceivable to automatically change the slow descent speed based on the magnitude of the deviation from the set depth in the slow descent region underground after switching to slow descent using the .

As explained above, according to the automatic elevation control mechanism for ground working equipment according to the present invention, the ground working equipment can be lowered from mid-air to almost touching the ground, regardless of changes in the working depth or changes in the amount of sinking of the tractor itself. It is possible to reach the set working depth as quickly as possible by quickly descending to the set working depth, and then slowly descending to the set working depth, thereby minimizing the impact of the work equipment entering the ground. Even when lowered while moving, the time it takes for the working equipment to reach the set working depth is short, so the unprocessed area (remaining part for tilling equipment) where the working equipment travels without touching the field is reduced, making it more efficient. In particular, with the present invention, even in the slow descent underground, the descent is fast when it is shallow and slows down until it gets deeper, so Compared to the case where constant slow descent control is performed over the entire area, it is now possible to reach the set depth more quickly while accurately performing stable control with less overshoot.

[Brief explanation of the drawing]

The drawings illustrate an embodiment of the automatic lifting control mechanism for a ground work device according to the present invention, and FIG. 1 is a side view showing the rear part of the tiller, and FIG. 2 is a control circuit diagram. 1...Tractor, 2...Ground work equipment, 6...
Working depth setting device, 7...Working depth detection sensor.

Claims (1)

[Scope of Claims] 1. A sensor 7 for detecting the working depth based on the amount of vertical movement of the ground follower 8 is provided in the ground working device 2 which is attached to the tractor 1 so as to be able to rise and fall freely, and the detected working depth is set by the setting device 6. In the automatic lifting control mechanism of the ground working equipment, which is configured to automatically raise and lower the ground working equipment 2 based on the detection result of the sensor 7 so that the working depth is equal to the set working depth, the ground working equipment 2 is When the ground work device 2 is lowered, it is rapidly lowered in the descending region until the sensor 7 detects that the lower end of the ground work device 2 is almost at the ground surface level, and in the subsequent descending region to the set working depth, the work is continued. An automatic elevation control mechanism for ground work equipment, characterized in that a mechanism for switching the descending speed is linked to a sensor 7 so that the descending speed becomes slower as the depth increases. 2. The control mechanism according to claim 1, wherein the descending speed is switched in stages in the slow descending region. 3. Keep the absolute descending speed of the ground work device 2 constant,
The control mechanism according to claim 1 or 2, wherein the control mechanism is configured to continuously lower in a rapid lowering region and to lower intermittently in a slow lowering region.