JP2004125694A - Stay-preventing apparatus of combination balance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent articles from staying in a measurement hopper. <P>SOLUTION: Weights of articles contained in a plurality of measurement hoppers 2 are diversely combined. Among these weight combinations, a proper combination that has the total weight equal to or nearly equal to a target weight is selected. Articles constituting this proper combination are discharged from measurement hoppers 2 containing the articles. To the empty measurement hoppers 2, articles are newly supplied from corresponding supply hoppers 8 via linear feeders 10. Then, a proper combination is selected again. A CPU 22 detects staying articles that are not selected for a proper combination but contained in measurement hoppers. When a proper combination is formed so that the detected staying articles are included therein, the CPU 22 calculates a weight of articles to be added. The CPU 22 enables the articles having the calculated additional article weight to be supplied from a corresponding supply hopper 8 via a linear feeder 10 to any of measurement hoppers 2 constituting the proper combination. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a combination weigher, and more particularly to a combination weigher for preventing stagnation of articles.
[0002]
[Prior art]
The most basic form of the combination weigher includes a plurality of weighing hoppers as a plurality of article storage means. The weight of the articles in these weighing hoppers is measured. These weights are variously combined, and a combination having a total weight equal to or close to a predetermined target weight is selected from the combinations. The articles are discharged from the weighing hopper in which the articles constituting the selected combination are stored. An article supply means, for example, a straight-ahead feeder is provided corresponding to each weighing hopper. The articles are supplied to the empty weighing hopper from the linear feeder corresponding to the empty weighing hopper. When the articles are supplied to all the weighing hoppers, a combination is selected in the same manner as described above. The above description relates to the basic form, and in fact, between each weighing hopper and the corresponding straight-ahead feeder, a supply hopper to which articles are supplied in advance from the straight-ahead feeder is provided and emptied. The supply of goods to the weighing hopper is performed quickly. Also, each straight-ahead feeder is supplied with an article from a distributed feeder.
[0003]
In such a combination weigher, the straight-ahead feeder is set so that articles supplied to each weighing hopper are almost equal to a predetermined set supply weight in order to increase combination weighing accuracy. However, occasionally, due to the properties of the articles, more or less articles than the set supply weight may be supplied only to a specific weighing hopper. This article is hardly included in the selected combination and can stay in a particular weighing hopper for a long time.
[0004]
Conventionally, as a process for such a staying article, for example, there has been a process disclosed in Patent Document 1. That is, when the combination calculation is performed for a predetermined time, the articles of the weighing hopper that have never been selected as the combination are determined as the staying articles, and the staying articles are forcibly included to select the combination. [0005]
[Patent Document 1]
Japanese Utility Model Publication No. 1-89776
[Problems to be solved by the invention]
However, in such a stay prevention device, since the articles judged to be staying are forcibly tried to participate in the combination, depending on the weight of the articles stored in other weighing hoppers, the staying articles may not be included. Therefore, a combination equal to or close to the target weight may not be obtained. In preparation for such a case, the combination weigher disclosed in this publication is provided with an alarm device for prompting the manual discharge of the staying articles not selected as a combination.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a retention device for a combination weigher that can prevent articles from staying in an article storage means such as a weighing hopper.
[0008]
[Means for Solving the Problems]
The retention device for a combination weigher according to the present invention is provided on the combination weigher. In the combination weigher, the weights of the articles stored in the plurality of article storage units are variously combined, and a suitable combination whose total weight is equal to or close to the target weight is selected from these combinations. As the article storage means, for example, a weighing hopper can be used, or a weighing hopper and an auxiliary hopper supplied with articles from the weighing hopper can be used. The article is ejected from the article storage means that houses the articles that make up this matching combination. An article is newly supplied from the corresponding article supply means to the empty article storage means. As the article supply means, for example, a linear feeder vibrating at a predetermined amplitude can be used, or a supply hopper supplied with articles from the linear feeder can be used. When an article is newly supplied to the empty article storage means, the above-described suitable combination is selected again. A staying article detection unit detects a staying article that is not selected in the matching combination among the article storage units. As the means for detecting the staying articles, various means can be used. For example, after selecting a suitable combination for a predetermined time or a predetermined number of times, an article which has never been selected as a suitable combination is detected. At a suitable time, a suitable combination is selected while always including the articles of the specific article storage means, and if the article of the certain article storage means is not included in the compatible combination, the specific article is selected. The article in the storage means may be a staying article. By sequentially changing the specific article storage means, the staying articles can be detected from the articles of all the article storage means. When configuring the matching combination including the detected staying articles, the additional article weight calculating means calculates the additional article weight that needs to be added. The control means causes any one of the article storage means to supply the article having the calculated additional article weight from the corresponding article supply means.
[0009]
According to the retention device of the combination weigher configured as described above, the retained articles are detected, the weight of the articles to be added in order to include the retained articles in the compatible combination is determined, and the weight is added. You. Therefore, when the selection of the suitable combination as described above is started, a suitable combination including the staying articles is eventually selected. As described above, since the additional articles are positively supplied to any of the article storage means in order to forcibly put the staying articles in the matching combination, the probability that the staying articles are included in the matching combination and discharged is increased. Get higher.
[0010]
The additional article weight calculating means includes an average weight calculating means for calculating an average weight of the articles excluding the staying articles among the articles in each of the article storing means, a multiplier increasing by one from zero, and the average weight value. The multiplied value of, and the deviation of each of the total value of the weight of the staying articles from the target weight, among those smaller than the average weight value, additional article weight determining means for determining the additional article weight, I have it.
[0011]
When the additional article weight calculating means is configured in this manner, the sum of the additional article weight, the weight of the staying articles, and the appropriate average number of weight values is relatively close to the target weight. Therefore, there is a high possibility that a suitable combination including the staying articles can be selected, and the weight of the added articles decreases.
[0012]
The staying article detection means can select, from among the plurality of staying articles that are not selected for the matching combination, the one that has the greatest weight from the average weight of each article excluding each of the staying articles.
[0013]
There may be multiple staying articles. In this case, there is a high possibility that the article whose weight is farthest from the average weight of each article excluding the staying articles will stay for the longest time. Therefore, it is configured to discharge the article that is likely to stay for the longest time as a target. In addition, when a plurality of staying articles are present, the weight for discharging an appropriate number of staying articles can be calculated at the same timing.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The stagnation prevention device according to one embodiment of the present invention is implemented, for example, in a combination weigher as shown in FIG. This combination weigher has a plurality of article storage means, for example, a plurality of weighing hoppers 2. These weighing hoppers 2 are arranged on a predetermined circumference. The weight of the articles stored in these weighing hoppers 2 is measured by weighing means, for example, a load cell 4 individually attached to these weighing hoppers 2. Although not shown, these weighing hoppers 2 are provided with discharge means, for example, discharge gates, and articles contained therein are discharged to the collecting hopper 6 via these discharge gates.
[0015]
Above these weighing hoppers 2, a supply hopper 8, which is a part of the article supply means, is arranged corresponding to the weighing hoppers 2. Although not shown, the supply hopper 8 also has a discharge gate. When the weighing hopper 2 is empty, articles are supplied from a supply hopper 8 located above the hopper 2 via a discharge gate. These supply hoppers 8 are also located on a predetermined circumference.
[0016]
Corresponding to these supply hoppers 8, a plurality of rectilinear feeders 10 forming the remaining part of the article supply means are arranged. These linear feeders 10 have a trough 10a and a vibration source 10b for vibrating the trough 10a, and vibrate the vibration source 10b obliquely upward at a set amplitude for a set time, so that the trough 10a The articles are supplied to a corresponding supply hopper 8. In addition, a weighing means, for example, a load cell 11, for weighing articles on the trough 10a is attached to each of the rectilinear feeders 10 for use in control described later.
[0017]
In order to supply articles to the linear feeder 10, a dispersion feeder 12 is arranged at the center of the circumference where the linear feeder 10 is located. The dispersion feeder 12 has a top cone 12a and a vibration source 12b. By vibrating the vibration source 12b, the top cone 12a is twisted and turned, and the top cone is almost evenly placed on the trough 8a of each supply hopper 8. Supply the article on 12a. An article is supplied to the top cone 12a from a supply feeder 14 provided above the top cone 12a.
[0018]
In this combination weigher, as shown in FIG. 2, the linear feeder 10, the supply hopper 8, and the weighing hopper 2 located in the same vertical direction constitute one weighing unit 16. Therefore, in this combination weigher, a plurality of weighing units 16 are provided. A unit controller 18 is provided for each weighing unit 16.
[0019]
The vibrator control circuit 20 included in the unit control unit 18 operates the straight feeder 10 in response to a control signal from the CPU 22. Further, the gate drive circuit 24 controls the gate drive controller 26 in the weighing unit 16 in response to the control signal from the CPU 22 to open and close the gates of the weighing hopper 2 and the supply hopper 8. In addition, the analog weighing signals from the load cells 4 and 14 are converted into digital weighing signals by the A / D converters 28 and 30 in the unit control unit 18 and supplied to the CPU 22 for use in control by the CPU 22. . Further, the CPU 22 controls the distributed feeder 12 via the vibrator controller 34.
[0020]
The CPU 22 is provided with storage means, for example, a memory 35. According to the program stored in the memory 35, each weighing hopper 2, each supply hopper 8, each straight-ahead feeder 10, and the dispersion feeder 12 are controlled. The memory 35 is also used as a working area for performing such control. Further, an operation display unit 36 for setting a parameter used for performing this control, for example, a target weight or the like, and displaying a result of a combination calculation or the like is connected to the CPU 22.
[0021]
The basic operation of this combination weigher is as follows. Digital weighing signals from each load cell 4 representing the weight of the article in each weighing hopper 2 are combined in the CPU 22 in various ways. Among these combinations, the CPU 22 selects a matching combination whose total weight is equal to or closest to the target weight. The CPU 22 causes the collecting chute 6 to discharge the articles from the weighing hopper 2 in which the articles composing the matching combination are stored. Articles are supplied to the weighing hopper 2 emptied by this discharge from a supply hopper 8 located above the weighing hopper 2. The digital weighing signal of the newly supplied article is supplied to the CPU 22. When the digital weighing signals of the articles of all the weighing hoppers 2 are obtained, the CPU 22 selects a suitable combination as described above. After the supply of the articles from the supply hopper 8 to the weighing hopper 2 is completed, while the supplied articles are being weighed, the empty supply hopper 8 is supplied with the articles from the corresponding linear feeder 10. You. In this way, when the number of articles on the linear feeder 10 decreases, the CPU 22 operates the dispersion feeder 14 to supply the articles to the respective linear feeders 10.
[0022]
While such processing is being repeatedly performed, when an appropriate period has elapsed, for example, when a suitable combination is selected a predetermined number of times, the CPU 22 performs the following processing. The registers, counters, and pointers used in the following processing are configured by the CPU 22 by software.
[0023]
First, the processing shown in FIG. 3 is performed to detect a staying article. That is, the CPU 22 functions as a convection article detection unit. First, the values of a pointer m for designating the weighing hopper 2 and a counter p for counting the number of the weighing hoppers 2 in which the staying articles are stored are set to the initial value 0 (step S2).
[0024]
A combination operation is performed including the article of the weighing hopper 2 designated by the pointer m (step S4). That is, all combinations that always include the article of the weighing hopper 2 designated by the pointer m are created.
[0025]
Next, it is determined whether a matching combination exists (step S6). That is, it is determined whether there is a combination whose total weight is equal to or close to the target weight among the combinations created in step S4.
[0026]
If there is a compatible combination, that is, if the answer to the determination in step S6 is YES, the article in the weighing hopper 2 designated by the pointer m may be discharged, and the next weighing hopper 2 is designated. In order to do so, the value of the pointer m is increased by 1 (step S8). If there is no compatible combination, that is, if the answer to the determination in step S6 is no, there is no possibility that the article in the weighing hopper 2 specified by the pointer m is discharged, that is, since the article is a staying article, The weight Wm of the staying article is stored in the Wyp register designated by the counter p, and thereafter, the value of the counter p is increased by 1 (step S10). Then, step S8 is executed.
[0027]
Subsequent to step S8, it is determined whether the value of the pointer m is equal to the number H of all the weighing hoppers 2 (step S12). That is, it is determined whether or not the inspection has been completed for all the weighing hoppers 2 whether there is any staying article. If the answer to the determination in step S12 is NO, since the inspection has not been completed for all the weighing hoppers 2, the processing is executed again from step S4. If the answer to the determination in step S12 is yes, the inspection for all the weighing hoppers 2 has been completed, and thus the processing shown in FIG. 3 ends.
[0028]
Therefore, when a plurality of staying articles are present at the time when the processing shown in FIG. 3 is completed, the number of staying articles is stored in the counter p, and the weight of each staying article is stored in the Wyp register.
[0029]
When the processing in FIG. 3 ends, the processing in FIG. 4 is performed, and when there are a plurality of staying articles, it is determined which of the staying articles is to be discharged. That is, the CPU 22 functions as a staying article selection unit.
[0030]
First, it is determined whether a plurality of stay hoppers exist (step S14). That is, it is determined whether the value of the counter p is 1 in order to determine whether there are a plurality of weighing hoppers 2 storing the staying articles.
[0031]
If the value of the counter p is 1, there is only one weighing hopper 2 containing the staying articles, so that the value of the register Wy1 specified by the value of the counter p (= 1) is to be discharged. Is stored in the weight register Wy (step S16), and the processing in FIG. 4 ends.
[0032]
If the value of the counter p is not 1, since there are a plurality of weighing hoppers 2 containing the staying articles, the total weight WT of the articles other than the staying articles is calculated in order to calculate the average weight of the articles other than the staying articles. (Step S18). Next, an average weight is calculated by dividing the WT by a value obtained by subtracting a value of a counter p indicating the number of the weighing hoppers 2 containing the staying articles from the number H of all the weighing hoppers 2; It is stored in the average weight register WA (step S20). Hereinafter, the value of the average weight register WA is referred to as an average weight WA.
[0033]
Next, the degree of discreteness of the weight of each staying article with respect to the average weight WA is calculated, and the one with the largest degree of discreteness is calculated (step S22). That is, among the registers Wy0 to Wyp-1 that store the weight of each staying article, the register with the largest absolute value of the difference from the average weight WA is calculated. Then, the calculated weight of the staying article having the largest discreteness is stored in the weight register Wy of the article to be discharged (step S24). Hereinafter, the value of the weight register Wy of the staying articles to be discharged is referred to as the scheduled staying article weight Wy.
[0034]
When the weight Wy of the staying article to be discharged is determined in this way, the processing shown in FIG. 5 is performed, and the weight of the article to be added to discharge the staying article is determined. That is, the CPU 22 functions as an additional article weight calculating unit. In the process of FIG. 5, first, the value of a counter n that counts a multiplier for the average weight WA is set to 1, and the initial value of the weight of articles other than staying articles is set in a register W that stores a minimum value of the discreteness described later. The total value WT is stored (step S26). Hereinafter, the value of the register W is referred to as a minimum discreteness value W.
[0035]
Next, it is determined whether the weight Wy of the article to be discharged is larger than the target weight TW (step S28). If the answer to this determination is yes, it is impossible to discharge the staying articles by adding articles, so that an overweight error is displayed on the operation display section 36 (step S30), and FIG. The processing of 5 is ended.
[0036]
If the answer to the determination in step S30 is no, since the staying articles can be discharged by additionally charging, a candidate value of the additional weight is calculated, and the degree of discreteness of the candidate value with respect to the average weight WA is calculated. Is calculated (step S32). That is, the multiplied value of the value obtained by subtracting 1 from the value of the counter n and the average weight WA, and the weight Wy of the staying articles are subtracted from the target weight WT, and the subtracted value is stored in the additional weight candidate value register WXn. I do. Hereinafter, the value of the additional weight candidate value register WXn is referred to as an additional weight candidate value WXn. Further, the absolute value of the difference between WXn and the average weight WA is calculated and stored in the discreteness register Wn. Hereinafter, the value of the discreteness register Wn is referred to as discreteness Wn.
[0037]
It is determined whether the discreteness Wn is smaller than the minimum discreteness value W (step S34). If the answer to this determination is yes, the discreteness calculated this time is smaller than the minimum discreteness so far, so the minimum discreteness value W is updated to the current discreteness Wn, and at this time Is stored in the minimum additional weight register WX (step S36).
[0038]
Next, it is determined whether the value of the additional weight candidate value WXn is smaller than zero (step S38). If the answer to this determination is no, there is still a possibility that a new value is adopted as the additional weight, so the value of the counter n is increased by one (step S40), and the process returns to step S32. If the answer to this determination is yes, there is no additional weight candidate value any more, and the process of FIG. 5 ends.
[0039]
If the answer to the determination in step S34 is NO, the minimum discreteness up to now is smaller than the discreteness calculated this time, so the minimum discreteness value W and the value of the register WX are not updated, and the process proceeds to step S34. Execute S38.
[0040]
By performing such processing, when the answer to the determination in step S38 is YES, the minimum weight value that needs to be added to discharge the staying articles is stored in the register WX.
[0041]
If the articles are added to any of the weighing hoppers 2 by the weight stored in the register WX and a normal combination operation is executed, the possibility that the staying articles are discharged is increased. Therefore, the linear feeder 10 that supplies the articles to the supply hoppers 8 corresponding to any of the weighing hoppers 2 in which the staying articles are not stored, causes the CPU 22 to add the articles to the supply hoppers 8 by the value of the register WX. Controls the linear feeder 10. That is, the CPU 22 functions as control means.
[0042]
For example, let U be the weight of an article on the trough 10a of the straight-ahead feeder 10. In addition, the amplitude of the straight feeder 10 is set to a. Let T be the drive time of the straight-ahead feeder 10, and let α be a coefficient determined by the structure of the straight-ahead feeder 10 and the properties of the articles carried by the straight-ahead feeder 10. Assuming that the weight of the article to be supplied from the straight-ahead feeder 10 is W, W is obtained by W = α * U * a * T. Here, W is determined by the value of the register WX, and the value of U is measured by the load cell 11 (of course, when the straight feeder 10 is stopped). Since the value of α is known, by appropriately selecting a or T or both values, the articles of the value of the register WX can be supplied to the supply hopper 2 corresponding to any of the weighing hoppers 2 which do not contain the staying articles. 4 can be supplied. In this state, when the normal combination calculation is performed again, the staying articles are eventually included in the matching combination and discharged from the weighing hopper 2.
[0043]
The value of α can be determined, for example, by obtaining an appropriate number of sample values of W, U, a, and T in advance, and using, for example, a least squares method.
[0044]
In the above embodiment, since the supply hopper 8 is used, the articles in the supply hopper 8 are not supplied to the weigh hopper 2 unless the weigh hopper 2 becomes empty. Therefore, even if an article is added to the supply hopper 8 corresponding to the weighing hopper 2 containing the staying articles to be discharged, the articles in the supply hopper 8 contain the stagnating articles. Is very unlikely to be supplied to Therefore, additional articles are supplied to the weighing hopper 2 in which no staying articles are stored. However, in a configuration in which the articles are directly supplied from the rectilinear feeder 10 to the weighing hopper 2 without using the supply hopper 8, the value of the register WX corresponding to the value of the register WX is stored in the weighing hopper 2 containing the staying articles to be discharged. It is also possible to directly add an article having a small weight. In the above-described embodiment, when a plurality of staying articles are present, the additional weight is determined so as to discharge one of the staying articles. However, the additional weight is determined so that an appropriate number of the staying articles can be individually discharged. By calculating the value, the straight feeder 10 can be controlled. In the above-described embodiment, the detection of the staying articles is performed based on the flowchart shown in FIG. 3, but the present invention is not limited to this. For example, when the selection of the matching combination is performed a predetermined number of times, the matching is performed once. The articles of the weighing hopper 2 that have not been selected for the combination can also be determined as staying articles. In the above embodiment, only the weighing hopper 2 is used as the article storage means. However, the present invention is not limited to this. For example, the weighing hopper 2 and the corresponding weighing hopper 2 And an auxiliary hopper to which is supplied can be used as the article storage means. Although the straight feeder 10 is used, a chain conveyor or a belt conveyor may be used instead. Further, the weighing hopper 2 and the supply hopper 8 are arranged in a circular shape, but may be arranged in a non-circular shape such as a straight line.
[0045]
【The invention's effect】
As described above, according to the present invention, the weight of an article to be added in order to discharge a staying article in a compatible combination is determined, and the weight of the article is added to the article storage means. The stagnant articles can be included in the matching combination and discharged.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a combination weigher according to an embodiment of the present invention.
FIG. 2 is a block diagram of the combination weigher of FIG. 1;
FIG. 3 is a flowchart showing a process of detecting staying articles in the combination weigher of FIG. 1;
FIG. 4 is a flowchart illustrating a process of determining a staying article to be discharged from a plurality of staying articles in the combination weigher of FIG. 1;
FIG. 5 is a flowchart showing a process of determining the additional article weight necessary for discharging the staying articles determined in the flowchart of FIG. 4 in the combination weigher of FIG. 1;
[Explanation of symbols]
2 Weighing hopper (article storing means)
8 Supply hopper (article supply means)
10 Straight feeder (article supply means)
22 CPU (Stuck article detection means, additional article weight calculation means, control means)

Claims (3)

The weights of the articles stored in the plurality of article storage means are variously combined, and a suitable combination whose total weight is equal to or close to the target weight is selected from the combinations, and the articles constituting the suitable combination are selected. Discharging the articles from the stored article storage means, the empty article storage means, in a combination weigher that supplies a new article from the corresponding article supply means,
Of each of the article storage means, a staying article detecting means for detecting a non-selected staying article in the matching combination,
Including the detected staying articles, when configuring the matching combination, additional article weight calculating means for calculating the additional article weight that needs to be added,
Control means for supplying the calculated article having the additional article weight to any of the article storage means from the corresponding article supply means,
A retention device for a combination weigher. The retention device for a combination weigher according to claim 1, wherein the additional article weight calculating means includes:
Average weight calculating means for calculating the average weight of the articles excluding the staying articles among the articles of the respective article storage means,
Of the deviations from the target weight of the total value of the multiplier of the multiplier and the average weight value increasing by one from zero and the weight of the staying articles, the deviation of the total value smaller than the average weight value is determined as the additional article. Weight and an additional article weight determining means for determining the weight,
A retention device for a combination weigher. 2. The stay preventing device for a combination weigher according to claim 1, wherein the staying article detection unit is the most weighted from the average weight of each article excluding each staying article among a plurality of staying articles that are not selected for the matching combination. 3. A stagnation prevention device for a combination weigher that selects items that are far apart.

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