JPH0224448B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention measures the weight of foreign substances such as rocks mixed in root vegetables such as beets (sugar beets) and yams that are conveyed by a conveyor or the like. Concerning a measuring device.

[Prior art and its problems]

In general, freshly dug root vegetables contain a considerable amount of foreign matter such as stones, and they have approximately the same color but vary in size, and they are transported in large quantities in a short period of time. Despite this, the measurement of the weight of foreign objects is often left to visual inspection, which results in large errors and low reliability, so there is currently a strong desire for automation.

[Purpose of the invention]

This invention was made in view of these points,
To provide a measuring device capable of simply, quickly, and accurately measuring the weight of foreign substances mixed in root vegetables.

[Key points of the invention]

This invention utilizes the fact that when root vegetables or a foreign object collides with a plate-like member to generate an impact between them, the root vegetables and the foreign object have different frequency distributions due to the difference in their elastic modulus. By identifying the foreign object and detecting the displacement of the plate member at that point,
The weight, which is in a proportional relationship with this, is calculated by conversion.

[Embodiments of the invention]

FIG. 1 is an external configuration diagram showing an embodiment of the present invention. In the same figure, 3 ₁ and 3 ₂ are conveyors,
Reference numeral 4 designates a detection section, and 5 indicates a weight calculation display section. The detection section 4 is composed of a diaphragm (detection plate) 41, an elastic body 42 such as rubber or a spring, and a mounting base 43. Note that 1 is a root vegetable such as a beet, and 2 is a foreign object such as a stone.

Figure 2 is a block diagram showing the internal configuration of Figure 1;
FIG. 2A is a block diagram showing a specific example of the foreign matter determination circuit in FIG. 2. As shown in FIG. 2, inside the detection unit 4, an impact detector 44 and a displacement detector 45 are provided, while the weight calculation display unit 5 includes amplifiers 51, 53, a foreign object determination circuit 52,
It is composed of a peak value detection/holding circuit 54, a peak value integration circuit 55, a display section 56, etc. Furthermore, the foreign matter determination circuit 52 is composed of, for example, a filter F, a comparator C, and a setting device S as shown in FIG. 2A. has been done.

The functions and operations will be explained below with reference to these figures.

Root vegetables 1 containing foreign matter 2 are conveyed by a conveyor ₃₁ , and a detection unit 4 is installed at the end of the conveyor.
are arranged with a predetermined height, so that root vegetables and the like fall onto the detection plate 41. Due to this fall, an impact is generated between the detection plate 41 and the root vegetables 1 or the foreign object 2, and the elastic body 42 provided in the detection section 4 is displaced. The vibration or impact sound caused by this impact is detected by the detector 44, and since the elastic body 42 is displaced according to the weight of the falling object, the amount of displacement is detected by the detector 45. Although the amount of displacement of the elastic body 42 depends on the head difference between the conveyor 3 ₁ and the detector 4, it is assumed to be constant here. In addition, as means for detecting vibration or impact sound caused by impact, for example, a vibration accelerometer,
A well-known vibration sensor such as a vibration velocity meter or a vibration level meter, or an acoustic sensor such as a microphone can be used. In addition, as a displacement detection means, a so-called eddy current displacement meter is used, which applies the principle that a metal plate is arranged in relation to a high frequency coil, and the displacement of this metal plate causes an eddy current effect and changes in inductance.
Alternatively, a well-known device such as a resistance wire strain gauge type load cell that determines the amount of strain on the diaphragm due to the load from the amount of change in electrical resistance of a strain gauge may be used. The output from the detector 44 is amplified by an amplifier 51, and the output from the detector 45 is amplified by an amplifier 53.
2, applied to the peak detection/holding circuit 54. The foreign object determination circuit 52 compares the output obtained by passing the signal from the amplifier 51 through a predetermined filter F such as a high-pass filter with a predetermined value set by a setter S in a comparator C, thereby determining whether or not it is a foreign object. Make a judgment. In other words, as shown in FIGS. 3A and 3B, the output from the detector 44 is such that the frequencies at which the peak points of root vegetables and foreign objects occur are different due to the difference in their elastic modulus (see f ₁ and f _{2 )} . ), this is used to identify foreign objects.
Note that FIG. 3 is a graph showing the frequency distribution of impact sounds caused by root vegetables and foreign objects, where A in the figure is for a foreign object and B in the same figure is for a root vegetable. The foreign object determination circuit 52 outputs a predetermined output to the peak value detection/holding circuit 54 only when the falling object from the conveyor ₃₁ is a foreign object.
4 detects the peak value of the signal provided from the displacement detector 45 via the amplifier 53. This peak value is given to the peak value integrating circuit 55 each time, so the circuit 55 sequentially integrates the peak values, and the display section 56 displays the weight based on the output from the peak value integrating circuit 55. In other words, there is a relationship between the output from the displacement detector and the weight as shown in Figure 4, and in particular, there is an approximately proportional relationship between the peak value of the output and the weight, as shown by the dotted line in the figure. By detecting the peak value, integrating the peak value, and further performing a predetermined conversion, it is possible to display the total weight of foreign substances rooted in the root vegetables.

FIG. 5 is a timing chart for explaining the above operation.

Now, the output of the shock detector 44 or the amplifier 51
Assuming that the output waveform of is expressed as shown in Figure A, and the set value by the setter S is at the position indicated by the dashed-dotted line, at the time t ₀ when the output exceeds this set value, the output waveform from the comparator C as shown in Figure B is shown. I get the output. At this point, the output of the peak value detection/holding circuit 54 is:
Since the output value up to that point is held as shown in FIG. 4E, the foreign object determination circuit 52 outputs a reset pulse as shown in FIG. Thereafter, the peak value detection/holding circuit 54 includes a displacement detector 45 or an amplifier 53 as shown in FIG.
The peak value of the output from is detected and held. Therefore, in the peak value accumulating circuit 55 or a similar data processing device (not shown), from the time _t0 when the output is obtained from the comparator C or the time _t1 when the reset pulse is issued, respectively. By taking in the output of the peak value detection/holding circuit 54 after a predetermined timing, it is possible to add (integrate) the peak value of the displacement detector output obtained each time.

In the above embodiment, the peak value of the amount of displacement detected by the displacement detector 45 is detected and this peak value is integrated. Of course, it is also possible to integrate the displacement amount and integrate the integrated value. This is because the integral value is approximately proportional to the peak value, so the integral value of the displacement amount is proportional to the weight of the foreign object, similar to the peak value of the displacement amount. Further, depending on the shape of the foreign object, for example, in the case of a flat stone, the foreign object may hit the detection plate 41 multiple times. At this time, the output of the displacement detector 45 is
The waveform will be as shown in Figure A, and since the energy of the impact is separated into, for example, two impacts, the peak value will be smaller than the waveform in the case of one impact as shown in Figure 6B, but the integral value will be The sum S1+S2 is approximately equal to the integral value S3. Therefore, if the configuration is such that the integral value is determined, the weight can be accurately determined even if the foreign object hits the detection plate multiple times. In this case, in the block diagram shown in FIG. 2, an integrating circuit is provided in place of the peak value detection/holding circuit 54, and the integrated value of this integrating circuit is integrated by the integrating circuit 55, or by the displacement detector 45. The detected displacement amount may be ANDed with the signal from the foreign object determination circuit 55, and then directly led to the integration circuit (integration circuit) 55 for integration.

[Effects of the Invention] As described above, according to the present invention, root vegetables containing foreign matter are dropped onto a detection plate, and foreign matter is determined based on the vibration frequency of the impact generated at that time.
Only when it is determined that it is a foreign object, the amount of displacement of the detection plate at that time is converted into weight and integrated, which provides the advantage that the weight of the foreign object can be measured accurately and quickly. Therefore, for example, when buying a truckload of root vegetables, you can pay for the exact amount after removing the amount of foreign substances contained therein, so there is a risk of making an unreasonably high purchase. This has the effect of eliminating the

[Brief explanation of drawings]

FIG. 1 is an external configuration diagram showing an embodiment of the present invention;
Fig. 2 is a block diagram showing the internal configuration of Fig. 1, Fig. 2A is a block diagram showing a specific example of the foreign object detection circuit in Fig. 2, and Fig. 3 shows the frequency distribution of impact sounds caused by foreign objects and root vegetables. Graph, Figure 4 is a graph showing the relationship between displacement detector output and weight, Figure 5 is a timing chart to explain the operation, and Figure 6 is a graph showing the relationship between displacement detector output and weight.
The figure is an output waveform diagram of the displacement detector. Code explanation, 1... Root vegetables, 2... Foreign matter, 3 ₁ ,
3 ₂ ... conveyor, 4 ... detection section, 5 ... weight calculation display section, 41 ... detection plate, 42 ... elastic body, 43 ... mounting base, 44 ... impact detector, 45
...Displacement detector, 51, 53...Amplifier, 52...
... Foreign matter determination circuit, 54 ... Peak value detection/holding circuit, 55 ... Peak value integration circuit, 56 ... Display section, F ... Filter, C ... Comparator, S ... Setting device.

Claims (1)

[Scope of Claims] 1. In order to measure the weight of foreign substances while conveying root vegetables mixed with foreign substances by a conveying member, a plate-like member is provided with a step difference relative to at least the conveying member, and Impact generating means that generates an impact when root vegetables or foreign objects fall onto the plate-like member, detection means that detects the vibration frequency of the impact and the displacement of the plate-like member, and the vibration frequency distribution of the impact. A root vegetable, characterized in that the root vegetable comprises a discrimination means for discriminating at least foreign substances from the food, and a measurement means for measuring the weight from the displacement of the plate-shaped member, and the measurement means is caused to measure the weight each time the discrimination is made. A device to measure the weight of foreign matter mixed inside.