JPS6332411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reaping and harvesting machine such as a combine, in particular, a reaping device is provided with an ultrasonic transmitter and an ultrasonic receiver, which may be integrally or separately configured, and the transmitter detects the height of the reaping device above the ground by measuring the time from when the ultrasonic wave is emitted until the reflected wave of the ultrasonic wave on the ground is detected by the receiver;
The present invention relates to a reaping harvester equipped with a cutting height control device that controls the vertical elevation of the reaping device based on the detection result.

Conventionally, mechanical sensors with a contact part that comes into contact with the ground have often been used as sensors for detecting the height of the reaping device in mowing height control devices. It has the disadvantage that it is easily damaged by foreign objects such as stock roots and pebbles. In order to eliminate these drawbacks, it has recently been proposed to use a non-contact ultrasonic sensor.

By the way, the height detection sensor of the reaping device is
Generally, it is necessary to detect the height of the front end of the reaping device from the ground to prevent it from protruding into a high place on the ground, so the ultrasonic sensor mentioned above is also installed at the tip of the reaping device. It is preferable to install it behind the grass implements. However, for reasons of strength, the weeding tool is supported by a support frame below its tip and fixed to the reaping device, and the ultrasonic sensor is placed as high as possible from the ground in order to maintain sufficient detection accuracy. Due to the constraint that the support frame should be placed above the support frame, the support frame must be placed above the support frame. Therefore, since the receiver receives reflected waves from the support frame before receiving reflected waves from the ground, it is necessary to take some measures to prevent control malfunctions. Therefore, in the past, interference between the emitted waves and the support frame was prevented by, for example, bending the support frame so as to straddle the top of the ultrasonic sensor, or shifting the position of the ultrasonic sensor laterally from above the support frame. However, when adopting the ultrasonic sensor, there were some issues such as not being able to use the existing support frame, or having to prepare a special large weeding tool to cover and protect the displaced ultrasonic sensor. The drawback was that the structure of the harvester's body had to be redesigned as well.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an ultrasonic sensor that can be installed above the weeding tool support frame when the ultrasonic sensor is installed behind the weeding tool. The object of the present invention is to prevent the reflected waves from the ground and the support frame from being mixed up and causing a control malfunction.

In order to achieve the above object, the reaping harvester according to the present invention detects only the second reflected wave among the reflected waves received by the receiver after the transmitter emits ultrasonic waves as a reflected wave from the ground, The height above the ground of the reaping device is configured to be detected based on the time difference measurement between the time of this detection and the time when the ultrasonic wave is transmitted by the transmitter.
It has the following characteristics.

Because of this characteristic configuration, even if the ultrasonic sensor is placed above the weed breaker support frame, the first received reflected wave signal corresponding to the reflected wave from the support frame is ignored and the reflected wave from the ground is ignored. Since only the second received reflected wave signal corresponding to the wave can be used as the signal for detecting the height above the ground, it is possible to prevent control malfunctions due to the presence of the support frame. And by this,
When installing an ultrasonic sensor, there is no need to change the configuration of the aircraft body and it can be used as is, and its installation position can be selected relatively freely.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view of a reaping device 1 at the front of a combine as a reaping and harvesting machine. A weeding tool 5 is provided in front. The lower end of the weeding tool 5 is fixed to a support frame 6 that is connected to the body frame. As shown in FIG. 2, which is a plan view of the front part of the reaping device 1, the ultrasonic sensors 7a and 7b are connected to the weeding tool 5 at both the left and right ends, that is, the uncut side end and the cut side end.
5, and is configured so that even if the reaping device 1 is tilted in the left-right direction, its average height can be detected. These ultrasonic sensors 7a and 7b are connected to the support frames 6 and 6, respectively.
It is attached to the weeding tools 5, 5 in a state where it is arranged above the weeding tools.

FIG. 3 is a block diagram of the control device, with 10
is a pulse generator that determines the timing when transmitting ultrasonic waves. This output (timing pulse) is input to the control calculation section 13, the left and right ultrasonic transmitters 8a, 8b, and the reset terminals of the 2-bit counters 11a, 11b. Therefore, ultrasonic waves are transmitted from the transmitters 8a and 8b at regular time intervals, and both counters 11a and 11b are reset. In addition, D
indicates a delay line, which removes the influence of direct waves during transmission. Comparators 12a and 12b are provided on the output sides of the receivers 9a and 9b, respectively.
When 9b outputs a potential higher than a predetermined level, the output is sent to 2-bit counters 11a and 11b. In addition, these 2-bit counters 11a, 11b
is from the second comparators 12a and 12b.
The high-order bit as a detection signal is output as a high level output and sent to the control calculation section 13. Transmitter 8a, 8
The ultrasonic waves emitted from b
It is diffusely reflected by the support frames 6, 6 and other parts of the reaping device 1, and enters the receivers 9a, 9b. Therefore, the receivers 9a and 9b output a potential according to the sound pressure of the received ultrasonic waves.
Since the sound pressure of diffusely reflected waves from sources other than 6 is low, the comparators 12a and 12b do not output detection signals thereof.

The control arithmetic unit 13 operates when the pulses from the pulse generator 10 are input and when the 2-bit counters 11a, 11
Measure the time difference when the detection signal from b is input, and use the average value of both time differences to detect the height of the reaping device 1 from the ground. It generates a signal for adjusting the height of the device 1. This signal is then sent to the hydraulic cylinder 1 that moves the reaping device 1 up and down.
This actuates the solenoid of the electromagnetic valve 15 provided in the hydraulic system No. 4.

It is also possible to provide means for measuring the time from the time of transmission to the output of the comparator, and to check for abnormalities by checking whether the first output arrives at approximately a predetermined time.

FIG. 4 schematically shows the signal pattern at each stage, where a is the emitted wave from the transmitters 8a and 8b, b is the received wave from the receivers 9a and 9b, and b ₁ is the emitted wave from the transmitters 8a and 8b. b ₂ is a reflected wave from the supporting frames 6, 6, and b ₃ is a reflected wave from the ground. C indicates a signal into which the reflected wave _b3 from the ground is converted and is input to the control calculation unit 13.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the reaping and harvesting machine according to the present invention, in which FIG. 1 is a front side view of the combine, FIG. 2 is a front plan view thereof, FIG. 3 is a block diagram of the control device, and FIG. The figure is a schematic diagram of signal waveforms at each stage. 5... Grass divider, 6... Support frame, 7a, 7
b... Ultrasonic sensor, 8a, 8b... Transmitter,
9a, 9b...Receiver, _b2 , _b3 ...Reflected waves.

Claims (1)

[Claims] 1. Transmitters 8a and 8b that emit ultrasonic waves towards the ground and a receiver that receives the reflected ultrasonic waves in order to detect the height above the ground of the reaping device 1 in order to control the cutting height. Ultrasonic sensors 7a, 7 consisting of 9a, 9b
b is a reaping/harvesting machine installed above the support frames 6, 6 of the weeding tools 5, 5, and after the transmitters 8a, 8b transmit ultrasonic waves, the receivers 9a, Reflected waves b ₂ , b ₃ received by 9b
Among them, only the second reflected wave _b3 is detected as a reflected wave from the ground, and at the time of this detection and the transmitter 8a,
A reaping/harvesting machine characterized in that it is configured to detect the height of the reaping device 1 above the ground based on the time difference measurement from the time when ultrasonic waves are transmitted by the reaping device 8b. 2. The first ultrasonic sensor 7a, 7b is characterized in that one each of the ultrasonic sensors 7a and 7b is provided on the uncut side edge weeding tool 5 and the cut side edge weeding tool 5.
Reaping harvester as described in section.