JP2005091294A - Combinatorial metering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow an operator to clearly grasp various kinds of information on the detection of cracked articles and to properly perform a supply processing depending on the information. <P>SOLUTION: Detection conditions for cracked articles included in good article weight probability distribution for each number of articles obtained from the average weight and standard deviation of single bodies are set by detection conditions setting means 41. Determining weight range calculating means 42, based on the set detection conditions for cracked articles, calculates a determining weight range for determining whether cracked articles, objects to be detected, are included or not. Cracked article determination means 35, based on the determining weight range calculated by the determining weight range calculating means 42 and a weight value of each point detected by metering means, determines whether cracked articles are included or not in articles stored in a hopper. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to the processing of missing parts in a combination weighing device that discharges articles each having a variation in weight together by a predetermined amount.

  A combination weighing device is used to collect articles each having a variation in weight such as confectionery, vegetables, fruits and the like by a predetermined weight.

  The combination weighing device weighs the articles supplied to multiple hoppers that can store and discharge articles, performs a combination calculation of the measured values, selects a combination whose combination weight falls within a predetermined range, and selects The items included in the combination are discharged from the hopper and put together.

  In such a combination weighing device, for example, when weighing an article such as a candy or a stick candy packed in a sachet, a missing item in which a part of the single item is missing may be supplied. If the product is included in the combination as an article having a large variation, a product including a missing product is produced.

  In order to solve this problem, in the following Patent Document 1, the average weight and standard deviation of a single object to be weighed are obtained in advance, and the weight taken by the weight probability distribution for each number of articles obtained from the average weight and standard deviation. Determine the range, and if the measured value is outside the weight range, determine that the hopper contains a defective product such as a missing product, and participate in the combined calculation of the measured values of the items contained in the hopper Is forcibly discharged to prevent combined discharge as a product.

Japanese Patent No. 2630824

  However, in the conventional combination weighing apparatus described above, the weight range (3σ or 4σ range) taken by the weight probability distribution for each piece obtained from the average value and standard deviation of a single product is set as a good product range, and other weight ranges are set. Since it is in the weight range of defective products, only limited missing products with a defect rate of about 1/2 such as semi-missing products can be detected, and 1/3 missing or 1/4 missing due to shape reasons, etc. It is difficult to detect a missing product contained in an article that is prone to occur.

  Also, it is not possible for the operator to clearly grasp the information on the detection of missing items, such as how many missing items can be detected, or how many items can be supplied. There is a problem, it is difficult to perform appropriate supply processing according to the information, excessive supply that can not detect missing items is made, many products containing missing items are manufactured, or operation is performed with excessive supply There was a problem such as reducing the efficiency.

  It is an object of the present invention to provide a combination weighing device that solves this problem and enables an operator to clearly grasp various pieces of information regarding the detection of a missing product and perform an appropriate supply process according to the information. It is said.

In order to achieve the above object, a combination weighing device according to claim 1 of the present invention comprises:
A plurality of hoppers (21) capable of accommodating and discharging articles;
Weighing means (23, 34) for detecting the weight of the articles accommodated in the hopper,
Unit information setting means (40) for setting the average weight and standard deviation of a single item to be weighed as unit information;
Detection condition setting means (41) for setting a detection condition for a missing item included in the non-defective product weight probability distribution for each number of articles obtained from the single unit information;
A weight range calculation unit for determination (42) for calculating a weight range for determination for determining whether or not a defective product to be detected is included based on the single unit information and the detection condition of the missing product;
Based on the determination weight range calculated by the determination weight range calculation means and the weight value detected by the weighing means, it is determined whether or not the article contained in the hopper contains a missing item. A missing item determination means (35);
Combination selection means for selecting a combination that falls within a predetermined target range from among the combinations whose weights are detected by the weighing means, excluding the articles that are determined to be missing by the missing article determination means. 36)
Non-defective product discharging means (37) for discharging the articles selected by the combination selecting means from the hopper;
And a missing item discharge means (38) for discharging an article determined to be missing by the missing item determination means from the hopper.

Further, the combination weighing device according to claim 2 of the present invention is the combination weighing device according to claim 1,
The detection condition setting means is configured to detect a range of a defect rate for a defective product to be detected, and an overlap limit between a missing product weight probability distribution of an article including the defective product having the defect rate and the non-defective product weight probability distribution. Configured to set as
The determination weight range calculation means is within a weight range taken by an article including a missing product within a set defect rate range, and the degree of overlap between the non-defective product weight probability distribution and the missing product weight probability distribution is within the limit. This weight range is calculated as a determination weight range.

The combination weighing device according to claim 3 of the present invention is the combination weighing device according to claim 1,
The detection condition setting means is configured to set, as a detection condition, a mixing probability that a missing item is included in an item to be weighed,
The determination weight range calculation means calculates a weight value that divides the non-defective product weight probability distribution into the mixing probability portion and other portions as a limit value of the determination weight range.

Moreover, the combination weighing device according to claim 4 of the present invention is the combination weighing device according to any one of claims 1 to 3,
An indicator (32);
A recommended supply number calculating means (43) for calculating, as a recommended supply number for the hopper, an upper limit number of articles capable of detecting an article including a missing item based on the detection condition;
Recommended supply number display means (44) for displaying the recommended supply number calculated by the recommended supply number calculation means on the display.

Further, the combination weighing device according to claim 5 of the present invention is the combination weighing device according to claim 4,
A supply device (22) for supplying articles to the plurality of hoppers;
Supply control means (39) for controlling the supply device so that the number of articles supplied to each hopper becomes the recommended supply number.

  With this configuration, the combination weighing device of the present invention calculates the weight range for determination based on the detection condition set for the missing product included in the non-defective product weight probability distribution, and whether the missing product is included. Therefore, it is possible to detect a missing product under a desired detection condition.

  In addition, in the case of having a means for calculating and displaying the upper limit number of articles capable of detecting articles including missing articles based on the detection conditions as the recommended supply number for the article receiver, the hopper including the missing articles is provided by the operator. It is possible to accurately grasp the maximum supply number of articles that can be detected, and to accurately perform a supply operation, a supply amount setting operation, and the like.

  In addition, in the case of having a supply device for supplying articles to a plurality of article receivers and having a means for controlling the supply apparatus so that the number of articles supplied to each article receiver becomes the recommended supply number, there is a lack due to the set conditions. Product detection can be performed efficiently.

  By setting the defect rate range of the missing item to be detected and the overlap limit of the non-defective product weight probability distribution and the missing product weight probability distribution as detection conditions, it is possible to intuitively determine how many missing items are targeted for detection, In addition, by obtaining the recommended number of supplies and controlling the supply amount of the supply device, it is possible to detect a missing product without reducing efficiency.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a configuration of a combination weighing device 20 to which the present invention is applied.

  The mechanism portion of the combination weighing device 20 includes a plurality of hoppers 21,..., 21 that can receive and discharge articles by opening and closing the bottom, a plurality of supply devices 22 that supply articles to each hopper 21,. .., 23 for weighing each of the articles supplied to the hopper 21, and an aggregator 24 for collecting and discharging the articles discharged from each hopper 21.

  In FIG. 1, the chute type collector 24 is shown, but a conveyor type collector 24 may be used. In addition, the chute type collector 24 is provided with a sorting mechanism 24a for sorting non-defective products determined not to contain missing products and defective products determined to contain missing products to different discharge paths. However, when the conveyor type collector 24 is used, it is possible to switch the discharge path between the non-defective product and the defective product by switching the transport direction.

  Each supply device 22 is constituted by, for example, a vibration conveyance type feeder, and the supply force of the article to the hopper 21 is determined by the vibration time or the vibration amplitude.

  Each weighing instrument 23 constitutes the weighing means of this embodiment together with the weight calculation means 34 of the controller 30 to be described later. Each weighing instrument 23 supports the hopper 21 and is accommodated in the supporting hopper 21 and the hopper. A weighing signal corresponding to the total load of the article is output to the controller 30.

  The controller 30 includes an operation unit 31, a display 32, and a control device 33 having a microcomputer configuration, and at least switching between an operation mode and a setting mode is possible by operation of the operation unit.

  In the operation mode, a weight detection process, a missing part detection process, a combination selection process, an article discharge process, an article supply process, and the like are performed based on the weighing signal from each weighing instrument 23.

  Further, in the setting mode, in response to the operation of the operation unit 31, various parameter setting processes necessary for driving the article to be weighed are performed.

  FIG. 2 shows a functional configuration of the control device 33. First, a portion that functions in the operation mode will be described.

  The weight calculation means 34 stores a weighing signal output from each weighing instrument 23 when no article is supplied to the corresponding hopper 21 as its own quantity in an internal memory (not shown), and the hopper itself. The weight value of the article is calculated by subtracting the amount from the weighing signal when the article is supplied.

  The missing item determination means 35 is an article housed in the hopper 21 based on the determination weight range Hr calculated in advance by the determination weight range calculation means 42 described later and the weight value Wx detected by the weight weighing means 34. It is determined whether or not there is a missing item.

  That is, if the weight value Wx is in the determination weight range Hr, it is determined that the article contained in the hopper 21 contains a missing item, and if the weight value Wx is not in the determination weight range Hr, It is determined that the article contained in the hopper 21 does not contain a missing item.

  The combination selecting means 36 is set in advance from among the combinations of the articles whose weights are calculated by the weight calculating means 34 except the hoppers that are determined to be missing by the missing article determining means 35. Select a combination that satisfies the target range. The target of the combination may be not only the weight but also the number, and in the case of the number, the combination is selected by converting the weight value of the articles of each hopper 21 into the number.

  The non-defective product discharging means 37 opens and closes the hopper 21 storing the articles selected by the combination selecting means 36 and discharges the stored articles to the collector 24.

  The missing product discharge means 38 is used by the non-defective product discharge means 37 at a predetermined timing, for example, when the total number of hoppers determined to contain the missing product by the missing product determination means 35 becomes a predetermined ratio or more of the total number of hoppers. Temporarily restricting the discharge of non-defective products, opening and closing the hopper 21 that has been determined to contain a missing product and discharging it to the collector 24, and driving the sorting mechanism 24a to collect and discharge to a position different from the non-defective product .

  When the article is discharged from the hopper 21 by the non-defective product discharge means 37 and the missing article discharge means 38, the supply control means 39 drives the supply device 22 corresponding to the empty hopper to supply a new article. .

  The supply control unit 39 controls the supply force of each supply device 22 so that the supply number of articles to each hopper becomes a recommended supply number P calculated by a recommended supply number calculation unit 43 described later.

Next, the part which functions in the setting mode will be described.
The unit information setting means 40 is for setting the average weight A and the standard deviation σ of the single item to be weighed in advance as the single unit information. For example, before the weighing operation, the unit weight of the unit is set to a predetermined number. The average weight A and standard deviation σ are calculated with a scale or the like, and the calculated values are set and stored by operating the operation unit 31.

  Further, without using a separate scale, the articles to be weighed are supplied one by one to the hopper 21 of the weighing device 20 to measure the unit weight, and the average weight A and the standard deviation σ are calculated inside the controller. May be.

  The detection condition setting means 41 is for setting a detection condition for a missing product included in the non-defective product weight probability distribution for each number of articles obtained from the single unit information. For example, the range of the missing rate for the missing product to be detected. And the overlap limit between the missing product weight probability distribution and the non-defective product weight probability distribution of the article including the missing product of the defect rate is set as a detection condition.

  The determination weight range calculating means 42 calculates a determination weight range Hr that serves as a reference for determining whether or not a detection target missing item is included based on the single unit information and the missing item detection condition. As described above, when the defect rate range and the overlap limit of distribution are set as the defect detection condition, it is within the weight range of the article including the defect rate range and the non-defective product. A weight range in which the degree of overlap between the weight probability distribution and the missing part weight probability distribution is within a preset overlap limit is calculated as the determination weight range Hr. In this case, the weight range that is expected to include the missing product to be detected is used as the judgment weight range. Conversely, the other range, that is, the weight range that is expected to be non-defective is also used as the judgment weight range. Good.

  The recommended supply number calculating means 43 calculates the upper limit number of articles that can detect an article including a missing product based on the set detection condition of the missing product as a recommended supply number P for each hopper 21, and recommends the recommended supply. The number display means 44 displays the calculated recommended supply number P on the display 32.

  Next, the operation in the setting mode of the controller 30 of the combination weighing device 20 will be described.

Assuming that single item information (normal distribution of average value A and standard deviation σ) is set in advance for the item to be weighed, each weight probability distribution F (N) for each number N based thereon is shown in FIG. In addition, a normal distribution with an average value of N times and a standard deviation of N ^1/2 times, and the weight range H (N) taken by each weight probability distribution is
H (N) = N · A ± 4σ · N ^1/2
(The coefficient may be 3σ).

  In the following description, these weight probability distributions F (N) are referred to as non-defective product weight probability distributions in the sense that they are included in any of the distributions of non-defective products.

  Then, the detection condition setting means 41 sets the defect rate range (α to 1-α) of the missing product to be detected and the overlap limit β of the distribution. Here, α is an arbitrary value greater than 0 and less than or equal to 0.5, and β is an arbitrary value greater than 0 and less than 0.5.

  For this detection condition, as shown in FIG. 3, the determination weight range calculation means 42 is the upper limit of the weight range taken by each weight probability distribution G (N-α) for the article (N-α). The lower limit L (N) of the weight range taken by the weight probability distribution G (N-1 + α) for the value U (N) and (N-1 + α) is obtained by the following calculation.

U (N) = (N−α) · A + 4σ · (N−α) ^1/2
L (N) = (N-1 + α) A + 4σ · (N-1 + α) ^1/2

  Each range determined by the upper limit value U (N) and the lower limit value L (N) is a missing product weight range Hn (N) taken by an article including a missing product having a defect rate range of α to 1-α. Of these missing product weight ranges Hn (N), both ends overlap with the weight range H (N) of the non-defective product weight probability distribution F (N) (all in FIG. 3), and the overlap limit described later. For those that do not exceed, the weight range for determination Hr (N) is used to determine missing parts.

  Although not shown in FIG. 3, in a small number region when the standard deviation σ is small or when α is close to ½, at least one end of the missing product weight range Hn (N) is a non-defective product weight probability distribution F ( N) may not overlap. In such a number region, it is not necessary to forcibly limit the defect rate range of the missing product to be detected to α to 1-α, and the missing product weight range is a weight range taken by the non-defective product weight probability distribution F (N). A range obtained by extending to the end is set as a weight range for determination Hr so that a missing product having a wider defect rate can be detected.

  Further, when the standard deviation σ is large or the defect rate range α to 1-α is wide and the number N of articles increases, the non-defective product weight range H (N) taken by the non-defective product weight probability distribution F (N) and the above. The overlap width with the missing product weight range Hn (N) is increased, the probability of determining a defective product as a failure is increased, and the measurement efficiency is reduced.

  Therefore, the weight range for determination Hr is obtained by limiting the missing product weight range by the overlap limit β set as the detection condition.

  That is, as shown in FIG. 4, the weight value Q (N) for dividing each non-defective product weight probability distribution F (N) into β and other (1-β) is obtained, and each missing product weight range Hn (N) is obtained. Compared to the upper limit value U (N), for example, as shown in FIG. 4A, if the upper limit value U (N) is equal to or less than Q (N), the upper limit value of the determination weight range Hr (N) is set. When the upper limit value U (N) is larger than Q (N) as shown in FIG. 4B, the upper limit value of the determination weight range Hr (N) is set to Q (N). To do.

  Further, the recommended supply number calculating means 43 is an upper limit number of articles that can reliably detect a missing product in the defect rate range α to 1-α, that is, a weight value Q (N) corresponding to the overlap limit β. The maximum number for which the upper limit value is not limited is calculated as the recommended supply number P for each hopper 21. This value P is displayed on the display 32 by the recommended supply number display means 44.

  In this way, after the determination weight range Hr corresponding to the detection condition, the recommended supply number P, and the like are obtained, when the operation mode is shifted, articles are supplied from the supply device 22 to the hoppers 21 and their weights. Each value is detected.

  Then, each detected weight value is input to the missing item determination unit 35, whether or not a missing item is included is determined based on the determination weight range Hr, and the determination result is output to the combination selection unit 36. The

  The combination selection means 36 performs a combination calculation of the article weights excluding the hopper determined to contain a missing item, and the combination amount falls within a preset target weight range (may be a target number range). Is selected, and the selection result is output to the discharge control means 37 to cause the collector 24 to discharge the articles selected for the combination.

  Further, a new article is supplied from the corresponding supply device 22 to the empty hopper 21 after the article is discharged, and the weight detection process, the missing part determination process, the combination selection process, and the discharge process are repeated in the same manner as described above. The target amount of articles will be discharged sequentially.

  Then, for example, when the number of hoppers determined to contain a missing product reaches a predetermined number, the articles are discharged from the hopper 21 determined to contain the missing product by the missing product discharge means 38 and assembled. It is discharged to a position different from the non-defective product via the container 24 and the sorting mechanism 24a.

  As described above, in the combination weighing device 20 of the above-described embodiment, means for setting the detection condition of the missing product and means for calculating the weight range for determining the presence or absence of the missing product based on the set condition. Therefore, the missing product can be detected and removed under conditions freely set by the operator.

  In addition, since it has means for calculating and displaying the maximum number of articles that can reliably detect missing articles based on the set detection conditions, the target of the number of articles supplied can be accurately determined, and the supply device 22 Adjustment can be performed easily.

  In addition, in the case of a semi-automatic combination weighing device in which an article is manually input by a person, the detection accuracy and efficiency of a missing item can be made compatible by inputting according to the recommended supply number.

  In the combination weighing device 20 described above, the defect rate range and the overlap limit of the distribution are used as the missing item detection conditions set by the detection condition setting unit 41. If it is known, the mixing probability γ can be set as a detection condition.

  In this case, as shown in FIG. 5, the determination weight range calculation means 42 divides each non-defective weight probability distribution F (N) into γ and other (1-γ) weight values U (N) ′, L (N) ′ is calculated as a limit value, and the range from the upper limit value U (N−1) ′ for N−1 to the lower limit value L (N) ′ for N A determination weight range Hr (N) for determining the presence or absence is used.

  In this case, the probability of determining a good product as defective is equal to the mixing rate γ and is constant regardless of the number, but as the number increases, the weight probability distributions F (N) approach each other, and the weight range of the distribution Overlap occurs, and the area of the mixing rate γ overlaps.

  Therefore, in this case, the maximum number that does not overlap the weight ranges of the adjacent non-defective product weight probability distributions F (N−1) and F (N) is obtained as the recommended supply number P.

  In the combination weighing device of the above-described embodiment, the supply of articles to the hopper 21 is automatically performed by the supply device 22. However, as described above, the semi-automatic combination weighing device that supplies articles to a plurality of hoppers manually is also provided. The invention (claims 1 to 4) can be applied.

Overall configuration diagram of an embodiment of the present invention Main part configuration diagram of the embodiment Weight probability distribution diagram for explaining the operation of the main part of the embodiment Weight probability distribution diagram for explaining the operation of the main part of the embodiment Weight probability distribution diagram for explaining the operation of the main part of the embodiment

Explanation of symbols

  20 …… Combination weighing device, 21 …… Hopper, 22 …… Supply device, 23 …… Weighing device, 24 …… Collector, 30 …… Controller, 31 …… Operating unit, 32 …… Display, 33 …… Control device 34... Weight calculation means 35... Missing product determination means 36... Combination selection means 37 .. Non-defective product discharge means 38 38 Defective product discharge means 39 39 Supply control means 40. Single unit information setting means 41... Detection condition setting means 42... Weight range calculating means 43. Recommended supply number calculating means 44. Recommended supply number display means

Claims (5)

A plurality of hoppers (21) capable of accommodating and discharging articles;
Weighing means (23, 34) for detecting the weight of the articles accommodated in the hopper,
Unit information setting means (40) for setting the average weight and standard deviation of a single item to be weighed as unit information;
Detection condition setting means (41) for setting a detection condition for a missing item included in the non-defective product weight probability distribution for each number of articles obtained from the single unit information;
A weight range calculation unit for determination (42) for calculating a weight range for determination for determining whether or not a defective product to be detected is included based on the single unit information and the detection condition of the missing product;
Based on the determination weight range calculated by the determination weight range calculation means and the weight value detected by the weighing means, it is determined whether or not the article contained in the hopper contains a missing item. A missing item determination means (35);
Combination selection means for selecting a combination that falls within a predetermined target range from among the combinations whose weights are detected by the weighing means, excluding the articles that are determined to be missing by the missing article determination means. 36)
Non-defective product discharging means (37) for discharging the articles selected by the combination selecting means from the hopper;
A combination weighing apparatus comprising: a missing item discharge unit (38) for discharging an article determined to be missing by the missing item determination unit from the hopper. The detection condition setting means is configured to detect a range of a defect rate for a defective product to be detected, and an overlap limit between a missing product weight probability distribution of an article including the defective product having the defect rate and the non-defective product weight probability distribution. Configured to set as
The determination weight range calculation means is within a weight range taken by an article including a missing product within a set defect rate range, and the degree of overlap between the non-defective product weight probability distribution and the missing product weight probability distribution is within the limit. The combination weighing device according to claim 1, wherein the weight range is calculated as a weight range for determination. The detection condition setting means is configured to set, as a detection condition, a mixing probability that a missing item is included in an item to be weighed,
2. The combination weighing according to claim 1, wherein the determination weight range calculation means calculates a weight value that divides the non-defective product weight probability distribution into the mixing probability portion and other portions as a limit value of the determination weight range. apparatus. An indicator (32);
A recommended supply number calculating means (43) for calculating, as a recommended supply number for the hopper, an upper limit number of articles capable of detecting an article including a missing item based on the detection condition;
4. The combination weighing apparatus according to claim 1, further comprising a recommended supply number display means (44) for displaying the recommended supply number calculated by the recommended supply number calculation means on the display. A supply device (22) for supplying articles to the plurality of hoppers;
The combination weighing device according to claim 4, further comprising a supply control means (39) for controlling the supply device so that the number of articles supplied to each hopper becomes the recommended supply number.

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