JP2925276B2 - Combination scale - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a combination weigher, and more particularly, to a combination weigher for controlling the number of article storage means such as a measuring tank to be subjected to a combination operation.

[Related Art] A combination weigher is, for example, a method in which articles are supplied to each weighing tank, the articles are weighed in the respective weighing tanks, and the measured values are combined in various ways. A combination calculation for selecting a combination equal to or close to the determined target weight is performed, and it is determined whether the selected total weight is within the allowable weight range. If the total weight is within the allowable weight range, the combination is configured. The normal discharging of the articles from the measuring tank as it is is performed, and when the weight is out of the allowable weight range, the defective discharging for replacing the articles in some of the measuring tanks with other articles is repeated. Conventionally, in such a combination weigher, when performing the above-described combination calculation, the weighing tank to be subjected to the combination calculation is set to a predetermined allowable lower limit or more,
Some of them are limited to the allowable upper limit or less. The reason for providing such a restriction is that if the combination calculation is performed on the number of weighing tanks smaller than the allowable lower limit, the combination weighing accuracy is reduced, and the number of weighing tanks larger than the allowable upper limit is targeted. This is because performing the combination operation increases the time required for the combination operation.

[Problems to be Solved by the Invention] By the way, as articles to be combined in such a combination weigher, individual weights are relatively uniform, such as broilers and fish fillets. We may use something that fluctuates. In such a case, if the above-mentioned allowable upper limit value and allowable lower limit value are fixed to predetermined fixed values, the rate of obtaining a combination falling within the allowable weight range is reduced, and for example, the ratio falls within the allowable weight range. Even only those that are close to the upper limit of the allowable weight range are selected. In such a case, it is necessary to increase the allowable upper limit value of the number of weighing tanks to be subjected to the combination calculation and increase the number of weighing tanks to be subjected to the combination calculation.

An object of the present invention is to provide a combination weigher capable of automatically increasing the allowable upper limit of the number of weighing vessels to be subjected to a combination operation in the above case.

[Principle of the Invention] In the first invention, a fractional ratio is used to automatically increase the allowable upper limit value of the number of weighing vessels to be subjected to the combination calculation. The fraction rate means that when a combination operation is performed a predetermined number of times, an average value (average selected number) of the number of articles selected each time is obtained, and a fraction below the decimal point generated in the average value is calculated as the average number. Divided by. The following table shows the relationship between the average selection number and the fractional ratio.

If the fraction exceeds 0.5, 1 is added to the original average selected number, and if the original fraction is α, 1−α is added to 1 to be the fraction of the average selected number.

As is clear from the above table, the closer the fraction is to 0.5, the higher the fraction ratio is, and the higher the fraction ratio is, the smaller the number of combinations is. For example, average selection number 1
The value of 3.5 indicates that there is a combination between the selected discharge numbers 13 and 14 that exactly matches the target weight. Therefore, it is determined that the number of appropriate combinations is small in this state. Therefore, when the fraction rate is large, the upper limit of the article storage means such as a measuring tank to be combined is increased,
It is necessary to increase the number of combinations.

Also, when comparing items having the same fraction among the average selected numbers, the fractional ratio is higher as the average selected number is smaller, and in this case, the higher fractional ratio means that the weight of each article is Large, indicating that the weight distribution of the article is narrow. Even in such a case, it is determined that the number of appropriate combinations is small as it is. Therefore, when the fraction rate is large, it is necessary to increase the upper limit value of the article storage means such as the measuring tank to be subjected to the combination calculation.

As described above, when the fractional ratio is large, the feature of the first invention is to increase the upper limit value of the article storage means to be subjected to the combination calculation.

According to the second invention, the failure rate is calculated not by calculating the fraction rate but by calculating the number of times the combination having the total weight within the allowable weight range is not obtained when the combination operation is performed a predetermined number of times. When the ratio is large, the upper limit value and the lower limit value of the article storage means such as the measuring tank to be subjected to the combination calculation are increased. A high defect rate indicates that the probability that a combination that falls within the allowable range is obtained with the current allowable upper limit value is small. Therefore, increase the allowable upper limit value and increase the number of obtained combinations. I have.

Embodiment FIG. 1 to FIG. 8 show a first embodiment. In this embodiment, the first invention is applied to a semi-automatic combination weigher in which articles are manually inputted and articles are automatically ejected. As shown in FIG. Upper wall part 4
The upper wall is formed with seven inlets 6 in a row as shown in FIG. A supply hopper 8 is provided in the main body 2 so as to correspond to each input port 6.
These supply hoppers 8 have discharge gates 10a and 10b, and weighing hoppers 12 are provided below the supply hoppers 8, respectively. These weighing hoppers 12 are partitioned by a partition wall 14 into two chambers 16a and 16b. When the discharge gate 10a of the supply hopper 8 is opened, articles are supplied from the supply hopper 8 to the chamber 16a. When the discharge gate 10b is opened, articles are supplied from the supply hopper 8 to the room 16b. These weighing hoppers 12 are connected to a load cell 18 provided in the main body 2, and the load cell 18 in a state where an article is supplied to one room, for example, the room 16a.
The weight value of the other room, for example, 16b, is subtracted from the weight value previously stored from the weight value from the load cell 18 when the article is supplied to the other room, and the weight of the article in the other room is subtracted. Calculate the weighing value. Each weighing hopper 12 has a room 16
Discharge gates 22a and 22b are provided for discharging the articles from a and 16 onto a transport conveyor 20 provided below. The articles discharged onto the conveyor 20 are conveyed to a packaging machine (not shown), where they are collectively packaged.

FIG. 8 is a block diagram showing the electrical relationship of this embodiment. An analog weighing signal from each load cell 18 is supplied to an A / D converter 24 via a multiplexer (not shown), and is converted into a digital weighing signal. The data is converted and supplied to the CPU 26. The CPU 26 operates according to the program stored in the ROM 28, and stores, for example, the measured values of the articles in the rooms 16a and 16b in the RAM 30 as described above. In addition, the combination calculation, the calculation of the fractional ratio, the control of the allowable upper limit value and the allowable lower limit value based on the calculated fractional ratio, discharge of articles from the rooms 16a and 16b,
The supply of articles to a and 16b, the control of the conveyor 20 and the like are performed. The discharge of articles from the rooms 16a and 16b,
The control of the supply of the articles to the a and 16b and the control of the conveyor 20 are performed by the CP.
U26 supplies a control signal to the drive circuit 32, and the drive circuit 32 controls the conveyor 20 in response to the control signal, and the gate drive device 34 controls the discharge gate 10a of the supply tank 8 according to the signal from the drive circuit 32, This is performed by controlling the discharge gates 10a and the discharge gates 22a and 22b of the measuring tank 12.

FIG. 1 is a flowchart showing the operation performed by the CPU 26. First, parameters are set (step S2). Here, the parameters are the allowable upper limit value n and the allowable lower limit value m when the fraction rate is smaller than the first allowable value α, and the allowable upper limit value when the fraction rate is equal to or more than the first allowable value and smaller than the second allowable value β. n + 1 and an allowable lower limit value m + 1, and an allowable upper limit value n + 2 and an allowable lower limit value m + 2 when the fraction ratio is equal to or more than a second allowable value. Initially, n and m are used as the allowable upper limit value and the allowable lower limit value. Subsequently, various operation constants are set (step S4). Here, the operating constants are the gate opening times of the discharge gates 10a and 10b of each supply hopper 8, the gate open times of the discharge gates 22a and 22b of the weighing hopper 12, the stable time when the weighing signal is considered to be stable, and the like. Since these operating constants are not directly related to the present invention, further explanation is omitted.

Next, the discharge gates 10a and 10b of the supply hopper 8 corresponding to the empty ones of the chambers 16a and 16b of each weighing hopper 12 are opened,
An article is supplied to each of the rooms 16a and 16b (step S6).

Subsequently, the elapse of the stabilization time is waited (step S8). Although not shown, the digital weighing signals after the lapse of the stabilization time are input, and the arithmetic operation for obtaining the digital weighing value of the article supplied to each room from these is performed. .

Then, based on the digital weighing value obtained as described above, the number of loading rooms to which articles are actually supplied is determined, and it is determined whether this is larger than the allowable lower limit (now m) (step S10). Steps S6 and S until they become larger
8. Repeat S10.

If it becomes larger (YES in step S10), it is determined whether the number of loading rooms is equal to or more than an allowable upper limit (now n) (step S1).
2). If it is not less than the allowable upper limit (step S12 is YES),
The number of rooms to be combined is selected so as to be equal to the upper limit (step S14). The details of step S14 will be described later. If it is not equal to or more than the allowable upper limit (step S12 is N
O), the number of loading rooms is set as the number of rooms to be combined (step S16). And after the end of step S14 or S16,
A combination operation is performed based on the digital weighing values of the room subjected to the combination operation (step S18). That is, the digital weighing values of the room subjected to the combination calculation are variously combined, and a combination having a total weight equal to the target weight value or larger than the target weight value and closest is selected from these combinations. Then, it is determined whether the total weight of the selected combination is an appropriate amount, that is, smaller than the allowable upper limit weight (step S20). If it is smaller, the total weight of the selected combination falls within the allowable weight range defined by the target weight and the allowable upper limit weight, so that the combination is appropriate. On the other hand, if the weight is larger than the allowable upper limit weight, it is out of the above-mentioned weight range, so that it is defective. Therefore, in the case of a defective product, defective discharge is immediately performed (step S22). That is, the articles in some rooms are discharged. Then, the process returns to step S6.

In the case of an appropriate quantity (YES in step S20), the total number of articles to be weighed in the room selected for the combination is calculated (step S2).
4), storing the calculated total number (step S26). Details of the process in step S24 will be described later.

Then, it is determined whether the total number has been stored a predetermined number of times (step S28). If the total number has not been stored, it is determined whether a discharge signal has been transmitted from the packaging machine (step S30).
If it has not been transmitted, step S30 is repeated until it is transmitted, and when transmitted, the selected articles to be weighed are discharged (step S32), and the process returns to step S6.

When the total number is stored a predetermined number of times (YES in step S28), the average number of selections in the predetermined number is calculated and displayed (step S28).
(S34), the fraction ratio is calculated and displayed (step S36), and the upper limit value and the lower limit value of the number of rooms to be subjected to the combination calculation are changed based on the fraction ratio (step S38). Then, steps S30 and S32 are executed, and the process returns to step S6.

In this way, every time an article is ejected a predetermined number of times, the average number of selected articles is calculated for the predetermined number of times, the fractional rate is calculated based on this, and the upper limit value and the lower limit value are changed based on the fractional rate. doing.

The details of the process of setting the number of rooms to be combined in step S14 equal to the upper limit value are as shown in FIG. 2, for example. That is, first, the counter C for counting the number of rooms to be combined is set to 0 (step S4).
0). The metric W _X of the articles of the room specified by the pointer X is, whether the threshold article in the room is accommodated
Determines whether there are P _W or more (step S42), and the threshold value P _W or more (Step S42 is YES), sets the specified room as the target room combinations X (step S44), the value of the counter C Is advanced by 1 (step S46).

If it is not equal to or larger than the threshold value _PW (NO in step S42), or after step S46, the value of the pointer X is incremented by 1 (step S48), and the value of the pointer X has become one larger than the total number h of rooms. It is determined whether or not the last room has been designated (step S50). If it has not been designated (step S50)
Is NO), it is determined whether the value of the counter C is equal to the upper limit value a (step S52), and if not, the process returns to step S42. If they are the same, the number of rooms can be specified by the upper limit, and this processing ends. If the last room is designated in step S50 (step S50 is YE
S), the value of the pointer X is set to 1, and the first room is designated,
Step S52 is executed.

The process of calculating the total number of articles to be weighed in the room selected for the combination in step S24 is performed, for example, as shown in FIG. That is, first, the value of the pointer X for sequentially designating each room is set to 1, and the area M in the RAM 30 for storing the total number is set.
_{The total is set} to 0 (step S56). Next, it is determined whether or not the articles in the room designated by the pointer X participate in the combination (step S58), and if so, the weight W _X of the articles in the room designated by the pointer X is divided by the unit weight W _AVE of the article. and to calculate the number N ₁ rounded to the decimal point of the division value N (step S60). Integrating the number N ₁ in M _total (step S62), the pointer X advances 1 (step S64). If the room designated by the pointer X does not participate in the combination (step S58 is NO), steps S60 and S62 are jumped to execute step S64. Subsequent to step S64, it is determined whether the value of the pointer X is greater than the value specifying the final room by one, that is, whether all rooms have been specified (step S66). Step S if all rooms are not specified
Return to 58. If all rooms are designated, M _total stores the total number of articles to be weighed in each room selected for the combination. Then, for use in the next calculation of the total number of articles to be weighed in the room selected for the combination, the total weight W _CMB of the articles of the selected combination is divided by the value of M _total to obtain a unit weight W _AVE is obtained (step S68), and this process ends.

As is clear from the above description, this processing assumes that the individual weight of each article, that is, the unit weight _WAVE is substantially the same. Note that, when this step S24 is executed for the first time, the unit weight _WAVE has not yet been obtained.
Therefore, before operating this combination weigher, a plurality of articles to be weighed are supplied to the room of the specific weighing hopper 12, the weighed value is read, and the weighed value is divided by the number of the weighed articles,
Obtain the first unit weight W _AVE .

Each time the processing of step S24 is performed, M _total
Are obtained, and when a predetermined number, for example, n pieces are obtained, step S28 is YES, and at this time, n pieces of M _total
Is added, and the added value is divided by n to calculate and display the average number of selected items.

The process of calculating and displaying the fraction ratio in step S36 is performed, for example, as shown in FIG. Now, assuming that the average selection number c calculated in step S34 is a numerical value in which a is an integer part and b is a decimal part, it is first determined whether the decimal part b is a value larger than 0.5 (step S). If it is not a large value,
This decimal part b is divided by the average selection number c, and the division value is
By multiplying by 100, a fraction ratio η is obtained (step S72). Also,
If the decimal part b is a value larger than 0.5, a value obtained by subtracting the decimal part b from 1 is set as a new decimal part b (step S7).
4) Add (a + 1) .b, which is obtained by adding 1 to the integer part a, to obtain a new c
(Step S76), and η is calculated in step S72. Then, η is displayed following step S72 (step S78), and this process ends.

The process of changing the upper and lower limit values of the number of rooms to be subjected to the combination calculation in step S38 is performed, for example, as shown in FIG. First, η calculated in step S36 is equal to a predetermined first
It is determined whether the value is smaller than the allowable value α (step S80). If it is smaller than α, the lower limit value is set to m and the upper limit value is set to n (step S82), and this process ends. If not smaller than α, it is determined whether η is equal to or larger than α and smaller than the second allowable value β (step S84). If η is larger than α and smaller than β, the lower limit is set to m + 1 and the upper limit is set to m + 1. The value is changed to n + 1 (step S86), and this process ends. η is not greater than α and β
If not less than the lower limit, m + 2 and the upper limit n + 2
(Step S88), and the process ends.

When the total number of rooms is 14, α and β are 2%,
4% can be used and m and n can be 9, 12 respectively.

FIG. 9 shows a second embodiment. In the first embodiment, the fraction rate is obtained, and the upper and lower limits of the number of rooms to be combined are changed in accordance with the fraction rate, whereas in the second embodiment, the defective rate is calculated, The upper and lower limits of the number of rooms to be combined are changed according to the defective rate.

That is, the configuration of this embodiment is the same as that of the first embodiment, and the processing performed by the CPU 26 also includes steps S2 through S20.
The steps up to this are the same as in the first embodiment. And step
In S20, it is determined whether or not the total weight of the selected combination is applied. If the total weight is appropriate, a normal discharge setting is performed (step S90). That is, these rooms are stored in order to later discharge the articles from the rooms in which the articles making up the selected combination are stored. If it is not an appropriate amount, a replacement set for recombining is set up (step S92). That is, in order to replace the articles in some rooms with other articles, and to discharge the articles from some rooms later, these some rooms are stored. And
The value of a counter NG that counts the number of failures, that is, the number of times that the amount did not reach an appropriate amount, is increased by 1 (step S94). Subsequent to step S90 or step S94, the value of the counter y for counting the number of combination operations is increased by 1 (step
S96).

Next, it is determined whether the number of combination operations is a predetermined number, that is, whether the value of the counter y is, for example, n (step S98). If it is not n, it is determined that the discharge is normal (step S10).
0), if it is not a normal discharge, a defective discharge is immediately performed based on the replacement discharge set in step S92 (step S92).
S102), and return to step S6. If it is a normal discharge,
It is determined whether or not a discharge signal is supplied from the packaging machine (step S104). If not, step S104 is repeated until the signal is supplied, and if supplied, the article is discharged based on the normal discharge set in step S90. (Step S1
06), and return to step S6.

Supply, weighing, combination calculation, and discharge are performed in this manner. When the number of calculations becomes, for example, n, step S98 is YES.
The re-combination rate is calculated, that is, the defect rate is calculated (step S108). This is to divide the value of the counter NG by the value of the counter y and multiply the divided value by 100.

The upper limit value and the lower limit value of the number of rooms to be combined are changed based on the recombination rate calculated in this way (step S110). This change is performed in the same manner as in step S38 of the first embodiment shown in detail in FIG. 5, and a detailed description thereof will be omitted.

As described above, the number of rooms to be combined is changed based on the recombination rate.

In both of the embodiments described above, the present invention is applied to a semi-automatic combination weigher. However, a manual combination weigher that supplies and discharges articles manually and an automatic combination weigher that supplies and discharges articles automatically are also provided. The present invention can also be implemented. Further, in both of the above embodiments, the weighing hopper partitioned into two rooms is used. However, a normal weighing hopper that is not partitioned is used, or such a normal weighing hopper and a weighing hopper are provided below these weighing hoppers. A separate auxiliary hopper can also be used. Further, in both of the above embodiments, both the upper limit value and the lower limit value of the room to be subjected to the combination calculation are changed based on the fraction rate or the recombination rate. This is to increase the number of combinations obtained by increasing the upper limit and increasing the upper limit.
By increasing only the upper limit, the number of obtained combinations may be increased.

[Effects of the Invention] As described above, according to the present invention, when the fraction rate and the defective rate increase, the upper limit value of the article storage means such as the room of the weighing hopper to be subjected to the combination operation is increased. ,
The number of combinations obtained by the combination operation increases. Therefore, the combination selected by the combination calculation is less likely to be out of the allowable weight range, and a weight combination particularly close to the target weight can be obtained even within the allowable weight range.

[Brief description of the drawings]

FIG. 1 is a flowchart of a first embodiment of a combination weigher according to the present invention, FIG. 2 is a flowchart of a process of selecting the number of rooms to be combined according to the first embodiment to the same number as an upper limit, The figure is a flowchart of a process for calculating the total number of articles to be weighed in the room selected for the combination of the first embodiment,
FIG. 4 is a flowchart of a process of calculating the fractional rate of the first embodiment, FIG. 5 is a flowchart of a process of changing the upper and lower limits of the number of rooms to be subjected to the combination calculation of the first embodiment, FIG. 6 is a front view of the first embodiment, and FIG.
FIG. 8 is an electric block diagram of the first embodiment, and FIG. 9 is a flowchart of the second embodiment. 12… Measurement tank, 18… Load cell, 26… CPU.

Continuation of the front page (56) References JP-A-62-22028 (JP, A) JP-A-61-292525 (JP, A) JP-A-61-25027 (JP, A) JP-A-59-46517 (JP, A) , A) JP-A-58-190725 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01G 19/387

Claims (2)

(57) [Claims] An article storage means for storing each of the supplied articles, and an article storage means for storing the articles in a state where the number of the article storage means in which the articles are stored is equal to or more than an allowable lower limit. The combination object article storage means determining means for selecting the article accommodation means having the allowable upper limit or less as the combination object article accommodation means, and various combinations of the weighing values of the articles in the combination object article accommodation means, and the total weight among these combinations. Calculating means for selecting a combination which falls within a predetermined allowable weight range, discharge instructing means for instructing discharge of articles constituting the selected combination, and a combination being selected a predetermined number of times by the combination calculating means. A fraction rate calculating means for calculating a fraction rate by dividing a fraction of the average value by the average value of the number of articles selected each time; Combination weigher and changing means for changing increase the allowable upper limit value when the rate is large, equipped. 2. An apparatus according to claim 1, further comprising: an article accommodating means for accommodating the supplied articles; and an article accommodating means accommodating the articles in a state where the number of said article accommodating means accommodating the articles is equal to or more than an allowable lower limit. The combination object article storage means determining means for selecting the article accommodation means having the allowable upper limit or less as the combination object article accommodation means, and various combinations of the weighing values of the articles in the combination object article accommodation means, and the total weight among these combinations. Calculating means for selecting a combination which is equal to or close to a predetermined target weight, determining means for determining whether or not the total weight of the selected combination is good, and instructing discharge of articles constituting the selected combination. When a combination is selected a predetermined number of times by the discharge instructing means and the combination calculating means, the failure rate is calculated by dividing the number of failures by the predetermined number of times. A defect rate calculating means, and changing means for changing increase the allowable upper limit value when the failure rate is high, comprising the combination weigher to be.