JP4128840B2 - Combination balance retention prevention device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combination weigher, and more particularly to an item that prevents 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 weighed. Various combinations of these weights are selected, and a combination in which the total weight is equal to or close to a predetermined target weight is selected from these combinations. Articles are discharged from the weighing hopper that contains the articles that make up the selected combination. Corresponding to each weighing hopper, article supply means, for example, a linear feeder is provided. Articles are supplied to the emptied weighing hopper from the linear feeder corresponding to the emptied weighing hopper. When the articles are supplied to all the weighing hoppers, the combination is selected in the same manner as described above. The above description relates to the basic form, and in fact, a supply hopper in which articles are supplied in advance from the linear feeder is provided between each weighing hopper and the corresponding linear feeder, and is empty. The supply of goods to the weighing hopper is performed quickly. In addition, articles are supplied to each linear feeder from the distributed feeder.
[0003]
In such a combination weigher, in order to improve the combination weighing accuracy, the linear feeder is set so that the articles supplied to each weighing hopper are substantially the same as a predetermined set supply weight. However, sometimes the article is supplied to the specific weighing hopper more or less than the set supply weight due to the property of the article. This article is not easily included in the selected combination and may stay in a particular weighing hopper for an extended period of time.
[0004]
Conventionally, for example, Patent Document 1 discloses a process for such a staying article. That is, when a combination calculation is performed over a predetermined time, an article of a weighing hopper that has never been selected as a combination is determined as a staying article, and a combination is selected by forcibly including the staying article. [0005]
[Patent Document 1]
Japanese Utility Model Publication No. 1-8976 [0006]
[Problems to be solved by the invention]
However, in such a stay prevention device, an article that is determined to be staying is forced to participate in the combination. Therefore, depending on the weight of the article stored in another weighing hopper, the staying article may be included. Thus, it may not be possible to obtain a combination that is equal to or close to the target weight. In order to prepare for such a case, the combination scale disclosed in this publication is provided with an alarm device for urging the manual discharge of staying articles not selected for the combination.
[0007]
An object of the present invention is to provide a stagnation prevention device for a combination weigher that can prevent stagnation of articles in an article storage means such as a weighing hopper.
[0008]
[Means for Solving the Problems]
The staying prevention device for the combination weigher according to the present invention is provided in the combination weigher. In the combination weigher, the weights of the articles accommodated in the plurality of article accommodating means are variously combined, and a matching 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 to which articles are supplied from the weighing hopper can be used. The article is discharged from the article accommodating means that accommodates the article constituting the matching combination. Articles are newly supplied from the corresponding article supply means to the emptied article storage means. As the article supply means, for example, a linear feeder that vibrates with a predetermined amplitude can be used, and a supply hopper to which articles are supplied from the linear feeder can also be used. When an article is newly supplied to the emptied article accommodating means, the selection of the matching combination as described above is performed again. A staying article detection means detects a staying article that is not selected for the matching combination among the article storage means. As a means for detecting this stagnant article , an appropriate combination is selected at an appropriate time in a state that always includes the article of the specific article accommodation means, and the article of the certain article accommodation means is not included in the adaptation combination. The article in the specific article storage means is assumed to be a staying article . By changing the specific article storage means in order, the staying articles can be detected from among the articles of all the article storage means. The additional article weight calculating means calculates an additional article weight that needs to be added when the matching combination is configured including the detected staying article. The control means causes the article having the calculated weight of the additional article to be supplied to any of the article storage means from the corresponding article supply means.
[0009]
According to the staying prevention device of the combination weigher configured as described above, the weight of the article to be added to detect the staying article and to include the staying article in the matching combination is determined and added. The Therefore, when the selection of the matching combination as described above is started, the matching combination including the staying article is selected. As described above, since the additional articles are positively supplied to any of the article accommodating means in order to forcibly put the remaining articles into the compatible combination, there is a probability that the remaining articles are included in the compatible combination and discharged. 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 of the respective article accommodating means, a multiplier that increases by one from zero, and the average weight value. An additional article weight determination means for determining, as the additional article weight, a deviation smaller than the average weight value among the deviations of the total value of the product value of the accumulated article and the weight of the staying article from the target weight, It has.
[0011]
If the additional article weight calculation means is configured in this way, the sum of the additional article weight, the weight of the staying articles, and an appropriate number of average weight values is relatively close to the target weight. Accordingly, the possibility of selecting a suitable combination including a staying article is increased, and the weight of the added article is reduced.
[0012]
The staying article detection means can select a staying weight that is farthest from the average weight of the articles excluding the staying articles among a plurality of staying articles that are not selected for the matching combination.
[0013]
There may be multiple staying articles. In this case, there is a high possibility that an article whose weight is farthest from the average weight of each article excluding the staying articles will stay for the longest time. In view of this, the article having the highest possibility of staying for the longest time is discharged as a target. In addition to this, when there are a plurality of staying articles, the weight for discharging an appropriate number of staying articles can be calculated at the same timing.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The stay 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 accommodated in these weighing hoppers 2 is measured by weighing means, for example, load cells 4, which are 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 accommodated therein are discharged to the collecting hopper 6 through these discharge gates.
[0015]
Above these weighing hoppers 2, corresponding to the weighing hopper 2, a supply hopper 8 that forms part of the article supply means is arranged. Although the supply hopper 8 is not shown, it has a discharge gate. When the weighing hopper 2 is empty, articles are supplied from the supply hopper 8 located above the weighing hopper 2 via the 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 constituting the remaining part of the article supply means are arranged. These linear feeders 10 have a trough 10a and a vibration source 10b that vibrates the trough 10a. By vibrating the vibration source 10b with a set amplitude in a diagonally upward direction for a set time, Articles are supplied to the corresponding supply hopper 8. For use in the control described later, each linear feeder 10 is provided with a weighing means, for example, a load cell 11, for weighing an article on the trough 10a.
[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 includes a top cone 12a and a vibration source 12b. By vibrating the vibration source 12b, the top cone 12a is twisted and swung, and the top cone is almost evenly placed on the trough 8a of each supply hopper 8. The article on 12a is supplied. The article is supplied to the top cone 12a from a supply feeder 14 provided thereabove.
[0018]
In this combination weigher, as shown in FIG. 2, the linear feeder 10, the supply hopper 8, and the weighing hopper 2 that are positioned 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]
A vibrator control circuit 20 included in the unit control unit 18 operates the linear feeder 10 in response to a control signal from the CPU 22. The gate drive circuit 24 controls the gate drive controller 26 in the weighing unit 16 in response to a control signal from the CPU 22 to open and close the gates of the weighing hopper 2 and the supply hopper 8. In addition, 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 in the CPU 22. . The CPU 22 also controls the distributed feeder 12 via the vibrator controller 34.
[0020]
The CPU 22 is attached with storage means, for example, a memory 35. Each weighing hopper 2, each supply hopper 8, each linear feeder 10, and the distributed feeder 12 are controlled according to the program stored in the memory 35. The memory 35 is also used as a working area when performing such control. In addition, an operation display unit 36 for setting parameters used when performing this control, for example, setting a target weight or displaying a result of combination calculation, is connected to the CPU 22.
[0021]
The basic operation of this combination weigher is as follows. The digital weighing signal from each load cell 4 representing the weight of the article of each weighing hopper 2 is combined in various ways in the CPU 22. 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 discharges the articles to the collecting chute 6 from the weighing hopper 2 in which the articles constituting this compatible combination are accommodated. Articles are supplied from the supply hopper 8 located above the weighing hopper 2 emptied by the discharge. A 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 an appropriate combination as described above. After the supply of the article from the supply hopper 8 to the weighing hopper 2 is completed, the article is supplied from the corresponding linear feeder 10 to the empty supply hopper 8 while the supplied article is being weighed. The When the articles on the linear feeder 10 decrease in this way, the CPU 22 operates the dispersion feeder 14 to supply the articles to each linear feeder 10.
[0022]
While such a process is repeatedly performed and 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 process. Note that the registers, counters, and pointers used in the following processing are configured by software by the CPU 22.
[0023]
First, the process shown in FIG. 3 is performed to detect staying articles. That is, the CPU 22 functions as a staying article detection unit. First, the initial value 0 is set to the values of the pointer m for designating the weighing hopper 2 and the counter p for counting the number of the weighing hoppers 2 in which the staying articles are accommodated (step S2).
[0024]
A combination operation including the article of the weighing hopper 2 designated by the pointer m is performed (step S4). That is, all combinations that always include the articles 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 in which the total weight is equal to or close to the target weight among the combinations created in step S4.
[0026]
If there is a matching combination, that is, if the answer to the determination in step S6 is yes, the article of the weighing hopper 2 designated by the pointer m may be discharged, so the next weighing hopper 2 is designated. In order to do this, the value of the pointer m is increased by 1 (step S8). If there is no matching combination, that is, if the answer to the determination in step S6 is no, the article of the weighing hopper 2 designated by the pointer m is not likely to be discharged, that is, is a staying article. The weight Wm of the staying article is stored in the Wyp register designated by the counter p, and then the value of the counter p is incremented by 1 (step S10). Then, Step S8 is executed.
[0027]
Following step S8, it is determined whether the value of the pointer m is equal to the number H of all weighing hoppers 2 (step S12). That is, it is determined whether or not the inspection has been completed for all the weighing hoppers 2 to have a stagnant article. If the answer to the determination in step S12 is no, the inspection has not been completed for all the weighing hoppers 2, and the process 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, so the processing shown in FIG.
[0028]
Therefore, when there are a plurality of staying articles when the process shown in FIG. 3 ends, 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 process of FIG. 3 is completed, the process of FIG. 4 is performed, and when there are a plurality of staying articles, it is determined which staying articles are to be discharged. That is, the CPU 22 functions as a staying article selection unit.
[0030]
First, it is determined whether there are a plurality of staying hoppers (step S14). That is, it is determined whether or not the value of the counter p is 1 in order to determine whether or not there are a plurality of weighing hoppers 2 that store stagnant articles.
[0031]
When the value of the counter p is 1, there is only one weighing hopper 2 containing the staying articles, so the value of the register Wy1 designated by the value of the counter p (= 1) is the article to be discharged. Is stored in the weight register Wy (step S16), and the process of FIG. 4 is terminated.
[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, this WT is divided by a value obtained by subtracting the value of the counter p representing the number of the weighing hoppers 2 containing the staying articles from the number H of all the weighing hoppers 2, to calculate an average weight, The average weight register WA is stored (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 with respect to the average weight WA of the weight of each staying article is calculated, and the one with the largest degree of discreteness is calculated (step S22). That is, among the registers Wy0 to Wyp−1 storing the weight of each staying article, the one having the largest absolute value of the difference with respect to the average weight WA is calculated. Then, the calculated weight of the stagnant article having the largest degree of 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 stagnant article scheduled to be discharged is referred to as a stagnant article weight Wy scheduled to be discharged.
[0034]
When the weight Wy of the staying article to be discharged is determined in this way, the process shown in FIG. 5 is performed to determine the weight of the article to be added to discharge the staying article. That is, the CPU 22 functions as additional article weight calculation means. In the process of FIG. 5, first, the value of the counter n for counting the multiplier with respect to the average weight WA is set to 1, and the weight of the articles other than the staying articles is set as an initial value in the register W for storing the minimum value of the discrete degree described later. The total value WT is stored (step S26). Hereinafter, the value of the register W is expressed as a minimum discrete value W.
[0035]
Next, it is determined whether or not the weight Wy of the scheduled discharge article 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 an overweight error is displayed on the operation display unit 36 (step S30). The process of 5 is finished.
[0036]
If the answer to the determination in step S30 is no, it is possible to discharge the staying articles by additionally inputting them, so that a candidate value for the additional weight is calculated, and the discrete value of the candidate value with respect to the average weight WA is calculated. Is calculated (step S32). That is, the product 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 article are subtracted from the target weight WT, and the subtraction value is stored in the additional weight candidate value register WXn. To 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 this WXn and the average weight WA is calculated and stored in the discreteness register Wn. Hereinafter, the value of the discreteness register Wn is expressed as discreteness Wn.
[0037]
It is determined whether this 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 The additional weight candidate value WXn 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, a new value may still be adopted as the additional weight, so the value of the counter n is incremented by 1 (step S40), and the process returns to step S32. If the answer to this determination is yes, there are no additional weight candidate values, and the processing in FIG. 5 is terminated.
[0039]
If the answer to the determination in step S34 is no, since the minimum discrete degree so far is smaller than the discrete degree calculated this time, the discrete degree minimum value W and the value of the register WX are not updated, and the step is performed. S38 is executed.
[0040]
By processing in this way, when the answer to the determination in step S38 is yes, the register WX stores the minimum weight value that needs to be added to discharge the staying articles.
[0041]
If an article is added to one of the weighing hoppers 2 by the weight stored in the register WX and a normal combination calculation is executed, the possibility that the staying article is discharged increases. Therefore, the CPU 22 is configured so that the linear feeder 10 that supplies articles to the supply hopper 8 corresponding to any of the weighing hoppers 2 that do not store the accumulated articles adds the articles to the supply hopper 8 by the value of the register WX. Controls the linear feeder 10. That is, the CPU 22 functions as a control unit.
[0042]
For example, the weight of an article on the trough 10a of the straight feeder 10 is U. Further, the amplitude of the rectilinear feeder 10 is a. The driving time of the linear feeder 10 is T, and the coefficient determined by the structure of the linear feeder 10 and the properties of articles conveyed by the linear feeder 10 is α. If the weight of the article to be supplied from the linear 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, measured when the linear feeder 10 is stopped). Since the value of α is known, the supply hopper corresponding to any weighing hopper 2 that does not contain stagnant articles can be obtained by appropriately selecting the value of a or T or both of the values of the register WX. 4 can be supplied. In this state, when a normal combination calculation is performed again, the staying articles are eventually included in the matching combination and discharged from the weighing hopper 2.
[0043]
Note that the value of α can be determined by, for example, obtaining an appropriate number of sample values of W, U, a, and T in advance and using, for example, the least square 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 weighing hopper 2 unless the weighing hopper 2 is emptied. Therefore, even if an article is added to the supply hopper 8 corresponding to the weighing hopper 2 containing the staying article to be discharged, the weighing hopper 2 containing the article in which the article in the supply hopper 8 stays. Is very unlikely to be supplied. Therefore, the additional article is supplied to the weighing hopper 2 in which the staying article is not accommodated. However, when the article is supplied directly from the linear feeder 10 to the weighing hopper 2 without using the supply hopper 8, it corresponds to the value of the register WX in the weighing hopper 2 containing the staying article to be discharged. It is also possible to directly add an article having a weight to be used. In the above embodiment, when there are a plurality of staying articles, the additional weight is determined so as to discharge one staying article, but the additional weight is set so that an appropriate number of staying articles can be discharged individually. It is also possible to control the linear feeder 10 by calculating a value. In the above-described embodiment, detection of stagnant articles is performed based on the flowchart shown in FIG. 3, but the present invention is not limited to this. For example, when a suitable combination is selected a predetermined number of times, it is adapted once. It is also possible to determine an article of the weighing hopper 2 that has not been selected for combination as a staying article. In the above embodiment, only the weighing hopper 2 is used as the article accommodating means. However, the present invention is not limited to this. For example, the weighing hopper 2 and the corresponding weighing hopper 2 are provided so as to correspond to the weighing hopper 2. The auxiliary hopper supplied with the item can also be used as the article storage means. Moreover, although the linear feeder 10 was used, it can replace with this and can also use a chain conveyor and a belt conveyor, for example. Furthermore, although the weighing hopper 2 and the supply hopper 8 are arranged in a circle, they can 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, it is configured to determine the weight of an article to be added in order to discharge the staying article in the compatible combination, and add it to the article accommodating means. The stagnant article can be included in a compatible 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.
FIG. 3 is a flowchart showing a process for detecting staying articles in the combination weigher of FIG. 1;
4 is a flowchart showing processing for determining a staying article to be discharged among a plurality of staying articles in the combination weigher of FIG.
5 is a flowchart showing a process for determining an 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 (item storage means)
8 Supply hopper (goods supply means)
10 Straight feeder (goods supply means)
22 CPU (Stagnant article detection means, additional article weight calculation means, control means)

Claims (2)

Various combinations of the weights of the articles stored in the plurality of article storage means are selected, and a matching combination whose total weight is equal to or close to the target weight is selected from these combinations, and the articles constituting the matching combination are selected. In the combination weigher that repeatedly discharges the article from the stored article storage means and supplies a new article from the corresponding article supply means to the empty article storage means.
In the middle of the repetition, when the suitable combination is selected in a state where the articles of one specific article accommodation means are always included among the respective article accommodation means, and the suitable combination cannot be obtained, the specific article accommodation means A stagnant article detecting means that sequentially changes the specific article accommodating means,
An additional article weight calculating means for calculating an additional article weight that needs to be added when the matching combination is configured including the detected staying article;
Control means for causing the article containing means to supply an article having the calculated additional article weight from an article supply means corresponding thereto,
Comprising the additional article weight calculating means,
Average weight calculating means for calculating the average weight of the articles excluding the staying articles among the articles of the respective article containing means;
Of the deviations from the target weight of the total value of the multiplier and the average weight value increased by one from zero and the weight of the stagnant article with respect to the target weight, the additional article is smaller than the average weight value. A weight and an additional article weight determining means for determining,
A staying prevention device for the combination weigher provided . 2. The stay prevention device for a combination weigher according to claim 1, wherein the staying article detection means is the most weight from an average weight of each article excluding each staying article among a plurality of staying articles not selected for the compatible combination. A combination weigh prevention device for selecting a combination weigher.

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