JP3427945B2 - Weight sorter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weight sorter for sorting according to the weight of weighted articles.

[0002]

2. Description of the Related Art Generally, a weight sorter is used for determining whether or not an item to be weighed contains an appropriate number of items, for example, incense sticks, mosquito coils or electric mosquito catch mats, and instructions. There is something to do. However, there is hygroscopicity such as incense sticks as described above, and an article whose weight becomes heavier with the passage of time, when contained in the weighted article, an appropriate number of articles in the weighted article Although included, it may be determined that the number of articles is excessive. On the other hand, if an article that is easy to dry and that tends to become lighter in weight over time is included, the number of articles will be insufficient even though the proper number of articles is included in the weighted article. It may be judged.

In order to solve such a problem, for example, there is a weight sorter disclosed in Japanese Patent Publication No. 61-12525. The principle of this weight sorter will be described with reference to FIG.

FIG. 9 considers a case where, for example, an article contained in the articles to be weighed absorbs moisture and becomes heavy in weight over time. At the start of operation of the weight sorter, the reference weight WT1 is set, and at the same time, the reference value WT1 is set.
It is assumed that the upper and lower limit deviations WU and WL are set centering around 1. When the weighing signal is Wx, an appropriate amount range of the articles to be weighed that are sequentially supplied is as shown by the equation 1 at first.

[Formula 1] WT1-WL ≦ Wx ≦ WT1 + WU

If the weights of the first weighted article to the fifth weighted article are W1 to W5, respectively, and if these values satisfy the expression 1, they are all non-defective. After weighing the fifth item to be weighed, the average weight W is calculated in accordance with Equation 2.

[Formula 2] W = (W1 + W2 + W3 + W4 + W5) / 5

This average weight is set as a new reference value WT2. Assuming that the weight of the sixth item to be weighed is W6, the quality is determined by using a new reference value WT2 and determining whether Expression 3 is satisfied.

[Formula 3] WT2-WL ≦ W6 ≦ WT2 + WU

If the expression (3) is satisfied, the reference value WT3 for judging the quality of the seventh weighted article is obtained by the expression (4).

[Equation 4] WT3 = (W2 + W3 + W4 + W5 + W6) / 5

The quality of the weight W7 of the seventh item to be weighed is judged by using WT3 obtained by the equation 4. In the same way, even if the weight of the weighted article gradually changes, if the weights of the weighted articles do not vary significantly, the reference value is corrected each time and the weight change tendency of the weighted article is used as a reference. The value can be tracked.

Note that, for example, the weight of the weighted article which is determined to be defective as a result of the quality judgment is not used for calculating the average value. For example, if W2 is a defective product, W1, W3, W
WT2 is calculated using 4, W5, and W6.

[0010]

However, when (1) the weight variation of the weighted article is large, (2) the weight variation of the weighted article is large and often falls outside the range of non-defective items, ( 3) When the setting range of the quality determination, for example, WT1-WL and WT1 + WU is narrower than the weight fluctuation range of the weighted article, the technique using the average value as the reference value as described above, It takes time to obtain a predetermined number of weighted articles to be measured, and moreover, since the reference value becomes the average value of the weight value group of these predetermined number of weighted articles, when the reference value is corrected, Since the weight change tendency of the weighed item has already changed, the correction reference value cannot track the weight change of the weighed item, and although it is actually a good item, it falls outside the range of good items and many Weighed articles were sometimes judged to be defective.

A similar problem is that an article whose physical properties change with the passage of time and whose weight increases or decreases is weighed by a device for filling a container or the like by a reference weight, and the weight is allowed. This occurs also in a weight sorter that controls a filling weight in a filling device on the basis of a difference between the average value and a reference weight, by collecting a predetermined number of pieces within the value.

[0012]

In order to solve the above-mentioned problems, the weight sorter according to the present invention (corresponding to the invention according to claim 1) is such that the objects to be weighed are supplied almost every predetermined time. , A weighing means for generating a weighing signal representing the weight of the item to be weighed for each supply, and comparing the weighing signal with two boundary values respectively set to be shiftable with respect to a reference value. However, the determination means for determining whether or not the weighing signal is within the allowable value range, the weighing signal determined to be within the allowable value range, and the number of times the weighing signal is weighed Based on the least-squares method, the storage means for sequentially storing the number of times of weighing indicating whether the item is a weighted article and each of the weighing signals and the number of times of weighing of the storage means are associated with each other. And an estimating means for estimating the reference value at the time of the next weighing.

Another weight sorter according to the present invention (corresponding to the invention according to claim 2) is supplied with an object to be weighed, and generates a weighing signal representing the weight of the object to be weighed for each supply. The weighting means for comparing the weighting signal with the two boundary values that are set to be shiftable with respect to the reference value, and determine whether the weighting signal is within the allowable value range. Determination means, storage means for sequentially storing the weighing signal determined to be within the allowable value range, and weighing time of this weighing signal, and each weighing signal and each weighing signal of this storing means. And an estimation means for estimating the reference value at the next weighing time based on the least squares method using the weighing time.

Further, according to another aspect of the present invention, a weight sorter (corresponding to the invention of claim 3) is provided with a means for filling a container to be loaded with articles to be weighed by a reference weight for about a predetermined time. And a weighing means for generating a weighing signal representative of the weight of the weighted article each time the weighted articles loaded into the container are sequentially weighed, and each time the weighing is performed. Determination means for determining whether or not the weight signal is within the allowable value range, a weighing signal determined to be within the allowable value range, and a weighted article for which the weighing signal is weighed The storage means for sequentially storing the number of times of weighing indicating whether or not, using each weighing signal and each number of times of weighing of this storage means, in the next filling means based on the least square method. The estimation means for estimating the filling weight, and the filling weight estimated by this estimation means And filling control means for controlling the filling weight in the filling means on the basis of the deviation between the serial reference weight,
It is equipped with.

In each of the above weight sorters, the number of each weighing signal stored in the storage means and the number of weighing times or weighing times can be limited to a predetermined number. The storage means is composed of a shift register, and the value of each weighing number stored in the shift register can be reduced by a predetermined value.

[0016]

In each of the weight sorters according to the present invention, the weighing signal determined to be within the allowable value range and the weighing frequency or weighing time are stored in association with each other, and based on these, The standard value for the next weighing is estimated by the least squares method. In this way, when the reference value is estimated by the method of least squares, the estimated value is little affected by the time delay. In particular, when the value includes an error such as a vibration component or noise, such as a weighing signal, and the number of weighings can be regarded as almost constant, or the weighing time can be accurately measured, the least-squares method The use of can improve the accuracy of the estimate. By using such an estimated reference value, the allowable value range is shifted and the filling weight is controlled.

The number of weight signals used in the least squares method,
If the number of times of weighing or the number of weighing times is increased, the estimation accuracy of the reference value improves. However, if the amount is too large, the evaluation will take a long time, and the weight tendency of the item to be weighed may change during that time, and the tendency of the change of the weighing signal may not be correctly expressed by a function. Therefore, the number may be limited to a predetermined number as in the following embodiment.

In the case where the number is limited in this way, if the weighing time or the number of times of weighing is stored as it is in the storage means, the storage means may overflow.
Therefore, in order to prevent overflow, a value obtained by subtracting a predetermined value from the value of the weighing time or the number of times of weighing may be stored in the storage means as in the following embodiment.

[0019]

1 to 4, a first embodiment is shown. The weight sorter of this embodiment is similar to the weight sorter described in the section of the prior art, and whether or not the weighed articles include an appropriate number of articles, for example, specific articles and instructions. It is used to judge that the particular article is likely to become heavier due to moisture absorption or the like with the passage of time, or to be lighter due to drying or the like.

In this weight sorter, as shown in FIG.
The article to be weighed 4 is carried into the weighing conveyor 6 by the carry-in conveyor 2 almost every time a predetermined time elapses. The weighing conveyor 6 is provided with weighing means, for example, a load cell 8, and each time the weighing object 4 is carried into the weighing conveyor 6, an analog weighing indicating the weight of the weighing object. Generate a signal.

These analog weighing signals are amplified by the amplifier 10 and then converted into digital weighing signals by the A / D converter 12, and are converted into C through the input / output port 14.
It is supplied to the PU 16. A memory 18 is attached to the CPU 16 and includes a weight shift register 2 described later.
0, weight count shift register 22, weight count counter n
Although not shown, allowable deviations such as allowable upper limit deviation WU and allowable lower limit deviation WL are stored.

In addition to this, the CPU 16 uses the input / output port 1
The numeric keypad 26 is connected to the numeric keypad 26 and the display unit 28 via 4, and the numeric keypad 26 is used to set the above-described allowable upper limit deviation WU and the allowable lower limit deviation WL, for example, and the display unit 28 displays the selection result and an estimated reference value described later. Is displayed.

The processing performed by the CPU 16 will be briefly described with reference to FIG. First, N pieces of weighing signals, for example, W1 to WN, in which the weighing signal falls within the allowable value range are obtained. At the stage when the N number of weighing signals are obtained for the first time, the respective weighing signals W1 to WN and the number of weighings indicating how many times the respective weighing signals are based, for example, 1 to N. Using the least squares method, the regression line L1 is represented by Equation 5 with y as the weight signal and x as the weight count.

[Formula 5] y = m1 · x + n1

Since the regression line L1 typically represents the tendency of fluctuations in the weighing signal scattered with variations, at the time when the N-th item to be weighed is weighed, the regression line L1 and the following When the intersection of the number N + 1 of weighings is a, a has a meaning as an N + 1th predicted weight value in consideration of the fluctuation of the weighing signal from the 1st to the Nth. Therefore, if the y coordinate value of a is WT1, this WT1 can be estimated as a reference value for determining the quality of the (N + 1) th weighted article. That is, by using this WT1, the allowable upper limit deviation WU, and the allowable lower limit deviation WL, it is determined whether or not the weighing signal W (N + 1) satisfies Expression 6, whether or not it is within the allowable value range.

[Expression 6] WT1-WL ≦ W (N + 1) ≦ WT1 + WU

If W (N + 1) is also within the allowable value range, W
A regression line L2 is obtained by the least-squares method using a total of N weighing signals of 2, W3, ... W (N + 1) and the number of weighing times of 2, 3, ... (N + 1). Let b be the intersection of this L2 and the number of times of weighing N + 2, and let the y coordinate value of b be WT2.
Then, as in the case of Equation 6, the W (N + 2) th weighing signal W (N
It is determined whether +2) is within the allowable value range. Thus, the regression line L3 ... Is obtained by the least-squares method using the N weighing signals that sequentially change and the N weighing times. Estimate the reference value of and replace it with the previous reference value.

If the weighing signal is not within the allowable value range, for example, W (N + 2) is not within the allowable value range as shown in FIG. 3, the weighing signal of W (N + 2) is N + 3.
Is not used for the estimation of the weight signal of the second time, and the estimated reference value WT3 is obtained from the intersection c of the regression line L2 and the number of times N + 3 of weighting, and using this, whether the weight signal of the N + 3th time is within the allowable value range. Is determined.

As described above, since the degree of change of the weighting signal is obtained by using the least squares method and the reference value at the current weighting point is estimated, the averaging target section as in the conventional average value method is used. It is possible to obtain an estimated reference value that follows the change trend of the weighing signal without time delay compared to the one using an almost intermediate value of the total change of the weighing value in the above, and it is not within the allowable value range. The same effect is obtained even when there is a weighing signal.

Although the regression line, that is, a linear expression, was used to estimate the change trend of the weighing signal by the least squares method, n (n is a positive integer of 2 or more) is used to calculate the weighing signal more accurately. Change trends may be estimated. However, the linear expression is sufficiently practical.

The allowable upper limit deviation WU and the allowable lower limit deviation W
As L, the one used for determining the quality of the weighted article can be used as it is, or the one for estimating the reference value can be used separately from this for determining the quality.
In this case, the absolute value of the value is usually smaller than the allowable upper and lower limit deviation used for judging the quality of the weighted article.

The processing performed by the CPU 16 will be described in more detail with reference to the flowchart of FIG. CPU16
Is an N-stage weight shift register 20 for storing a weighing signal within the allowable value, a weighing number counter n for counting each weighing number, and a weighing signal within the allowable value. An N-stage number shift register 22 for storing the number of times of weighing is prepared in the memory 18.

Then, first, each stage of the weight shift register 20 and the number shift register 22 and the weighing number counter n are reset (step S2). Then, in preparation for the first weighing, the value of the weighing counter n is set to 1 (step S
4). Next, when the weighing timing comes (this weighing timing is not shown, the weighing conveyor 6 in FIG.
It is possible to provide an article detector such as a photoelectric detector on the carry-in side, activate a timer when an article is detected by the article detector, and set the weighing timing when the count value of the timer reaches a predetermined value. ), And the digital weighing signal Wx from the A / D converter 12 is input (step S6).

Then, using the predetermined reference value WT, the allowable upper limit deviation WU, and the allowable lower limit deviation WL, it is determined whether Wx satisfies Expression 7 (step S8).

[Formula 7] WT−WL ≦ Wx ≦ WT + WU

When the expression (7) is satisfied, non-defective product processing, for example, although not shown, is distributed to the non-defective product side by the distribution device provided on the carry-out side of the weighing conveyor 6 (step S1).
0). Then, the digital weighing signal Wx is input to the first stage of the weight shift register 20, and the value of the weighing number counter n is input to the first stage of the weighing number shift register 22 (step S12). Following this, in preparation for the next weighing, the count value of the weighing number counter n is incremented by 1 (step S
14). That is, in this embodiment, the same allowable value is used as the allowable value for selecting the quality of the objects to be weighed and the allowable value for obtaining the estimated reference value.

On the other hand, if the expression (7) is not satisfied in step S8, defective product processing, for example, distribution to the defective product side by the above-mentioned distribution device (step S18), and then step S14 is executed.

Subsequent to step S14, whether there is data in the final stage of both shift registers 20 and 22, that is, N digital weighing signals within the allowable value range and N corresponding weighing times are counted. It is determined whether each is stored (step S16). If not stored, the process returns to step S6 and the above-described operation is repeated. In the case of the example of FIG. 3, since it is assumed that all the digital weighing signals W1 to WN are within the allowable value range, step S6, until WN is input,
The loop of S8, S10, S12, S14 and S16 is repeated.

In the above assumption, when WN is input,
From the first stage to the last stage of the weight shift register 20, the digital weighing signals of WN ... W1 are stored in order from the first stage side, and from the first stage to the last stage of the weight count register 22, from the first stage side to N stage. ... The number of times of weighing of 1 is stored. Therefore, the determination in step S16 is YES, and the regression line y = ax + b is obtained according to the method of least squares by using the data in both shift registers 20 and 22 (step S20). A method for obtaining the regression line y = ax + b is known, and for example, revised applied mathematics (2) “Yoshimasa Michiwaki, Keizaburo Harumi, Shozo Matsuura, Showa 4
March 25, 2013, 5th edition, published by Corona Publishing Co., Ltd. "
Pp. 1-313.

Subsequently to this, a regression line y = ax + is obtained.
Substituting n for x in b (n represents the next number of times of weighing. At this point, for example, since WN is input in step S6, n is advanced by 1 in step S14. At the time of step S20, the value of n is N + 1.) And y are calculated and used as the next WT (step S20). After that, step S6 is executed through steps S22 to S28 described later.

Therefore, in the example of FIG. 3, the reference value WT2 for the (N + 1) th time is estimated at the time of the number of times of weighing N, and N + 1
Steps S6 and S8 are executed the next time, and step S8
If it is determined to be within the allowable value range in step S10, step S10
Step S12 is executed, and W (N + 1) is
(N + 1) is input to the weight shift register 20 at the first stage of the weight count register 22, respectively, and W1 and 1 at the last stage are discarded.

That is, from the first stage to the last stage of the weight shift register 20, W (N + 1).
Is stored, and (N + 1) ... 2 is stored in order from the first stage side to the last stage of the weight count shift register 22. Using these, a second regression line is obtained in step S19, and (N
+2) The reference value for the second time is estimated.

If W (N + 2) is input in step S6, W (N + 2) is input as described with reference to FIG.
If 2) is outside the allowable value range, steps S8 to S16 are executed, and then step S14 is executed (at this point, the value of the weight counter n becomes N + 3 in preparation for the next weight. Exist).

Therefore, W (N + 2) and (N + 2) are not input to the weight shift register 20 and the weight count shift register 22, and W (N + 1) ... W2 from the first stage to the final stage of the weight shift register 20. Is still stored, and (N + 1) ... 2 is stored in order from the first stage to the last stage of the weighting number shift register 22. Using these, the regression line is obtained in step S18. This regression line and the weight counter n
Value (N + 3) and the next WT (W in FIG. 3)
T3) is estimated.

With the above description as it is, the values of the weight count counter n and the weight shift register 22 increase successively, and if they are left as they are, they will overflow. In order to prevent this, step S is actually
22 to S28 are provided.

That is, after step S20, it is determined whether the value P at the final stage of the weight count shift register 22 is 1 or less (step S22). If it is 1 or less, nothing is processed and the process returns to step S6. If it is not 1 or less, the value Q necessary for shifting the value of the final stage to 1 is calculated (step S24). The value of each stage of the weighting number shift register 22 is decreased by the value of Q (step S26),
Then, the value of the weight counter n is also decreased by Q (step S28), and the process returns to step S6.

For convenience of explanation, FIG. 4 shows steps S22 to S28 in the case where the number of weighing shift register 22 is 5,
And the state of change in the value of the weight count counter n. For example, as shown in FIG. 7A, when the sixth weighing is finished, the first stage to the last stage of the weight count register 22 It is assumed that the number of times of weighing is stored as 6, 5, 4, 2, 1 toward the side, and the number-of-times counter n is 7 in preparation for the next weighing. In this state, the value P of the final stage is 1, so steps S22 to S6 are executed and there is no change in the values of the stages and the weight counter n.

When the seventh weighing is performed and the weighing signal at this time is within the allowable value range, as shown on the left side of FIG. , 6, 5,
4 and 2 are stored, and the value of the weighing counter n becomes 8. At this time, since the value P of the final stage is not less than or equal to 1, the determination in step S22 is NO, and in step S24, 1 (the value P of the final stage 2-1) is calculated as the value of Q, and the value of each stage is calculated. Is decreased by 1, and the value of the weighing counter n is also decreased by 1, resulting in the value shown on the right side of FIG.

In this state, the eighth weighing is performed, and if the weighing signal is within the allowable value range, as shown on the right side of FIG. 7C, from the first stage of the weighing frequency shift register 22. 7, 6, 5, 4, and 3 are stored toward the final stage, and the value of the weighing counter n becomes 8. At this time, the value P of the final stage is not less than or equal to 1, so the determination in step S22 is NO, and in step S24, 2 (the value P of the final stage, 3-1) is calculated as the value of Q, and the value of each stage is calculated. Is decreased by 2, and the value of the weighing counter n is also decreased by 2, resulting in the value shown on the left side of FIG.

In this embodiment, the weight shift register 20
The number of weighing signals and the number of weighings used in the least-squares method is limited to N by using the or the weighting number shift register 22. As explained in the action section, this is correct when using too much data, despite the changing trend of the weighing signal, which is affected by the old changing trend of the weighing signal. This is because the tendency of change cannot be grasped. For example, N is 1 in the case of such a weight sorter.
It is 0 to 30, and the time required to obtain these N weighing signals is about 1 to 5 minutes assuming that all the weighing signals fall within the allowable value range. Therefore, the weighing interval is 2 to 30 seconds.

The second embodiment is shown in FIGS. In this embodiment, the present invention is applied to a weight sorter used together with a filling device, and its schematic configuration is shown in FIG. 5. The same parts as those in the first embodiment are designated by the same reference numerals, The description is omitted. A filling means, for example, a screw feeder 30 is provided above the carry-in conveyor 2 so as to fill a container 32 fed into the carry-in conveyor 2 every predetermined time with a weighted article, for example, powder or granular material. .

The screw feeder 30 is designed to rotate the screw by the motor 34 to supply the objects to be weighed by the reference weight. However, even if the motor 34 is rotated at the same rotation speed, The physical properties of heavy articles change with the passage of time, and it becomes impossible to fill the container with the objects to be weighed by the reference weight.For example, even if the number of revolutions is the same, the filling weight tends to increase or decrease with the passage of time. To have.

Motor 3 of this screw feeder 30
4 is controlled by a filling control unit, for example, a motor driver and a motor control unit 36, and a rotation control signal is supplied to the motor control unit 36 from the CPU 16 via the input port 14.

The container 32 filled on the carry-in conveyor 2 every predetermined time is carried into the weighing conveyor 6 at almost every predetermined time because the carry-in conveyor 2 is operated at substantially the same speed. An analog weighing signal is generated in the load cell 8 in response to the carry-in, which is the amplifier 10 and the A / D converter 1
2 and the input / output port 14 to the CPU 16.

The processing in the CPU 16 is almost the same as that of the first embodiment, and is generally represented by the flowchart of FIG. However, in this embodiment, step S20 in FIG.
Instead of, as in step S201 shown in FIG. 6, an estimated reference value at the time of the next weighing calculated by the least square method using the weighing signals and the number of weighings within the N allowable value ranges. The difference from the reference value is calculated, and the motor controller 36 is set so that this difference becomes zero.
The difference is that the feedback control signal is supplied to.
Further, the modifications described in relation to the first embodiment can be similarly applied to the second embodiment. Even in this case, the number N of weighing signals and the number of weighings for obtaining the estimated reference value are, for example, about 10 to 30, respectively,
The time required to obtain N weight signals is N consecutive times.
When one weighing signal is obtained, it takes about 1 minute, for example.

Further, in the second embodiment, the screw feeder 30 is used as the filling means, but instead of this, for example, a hopper having a gate at the bottom is used, and the opening degree of the gate is controlled by the controller. What is changed according to the signal of may be used as the filling means.

A third embodiment is shown in FIGS. 7 to 9. First
In the second embodiment, the number of times of weighing is counted, the regression line is calculated by using the number of times of weighing, and the next reference value is estimated. The weighing is not always performed every time the same time elapses, and may cause an error. Therefore, in the third embodiment, the actual weighted time is measured and the reference value is estimated by the least square method using this. In addition, also in the third embodiment, the present invention is applied to a weight sorter similar to that of the first embodiment, and the schematic configuration thereof is the same as that of the first embodiment, and therefore the illustration is omitted. To do.

However, in order to count the weighted time, 1 m
A counter tx that automatically counts every second is provided separately. An area in the memory 18 can be used as the counter tx. Further, since the weighting time is used, the weighting time shift register as shown in FIGS. 8B to 8D is used instead of the weighting number shift register. Further, the counter n for counting the number of times of weighing is not provided.

The general operation of the third embodiment will be described.
The time when the second item to be weighed is weighed at time T0 (= 0)
As a result, the time T0 and the weighing signal W0 at that time are stored in the weight shift register 20 and the first stage of the weighing time shift register, respectively. In particular, it is not necessary to store the time T0 (= 0), but it is temporarily stored as a set with W0.

The time from the first to the second weighing is counted by the counter tx, and the value tx and T0 are counted.
(= 0) is added to obtain the second weighing time T1,
The weight shift register 20 together with the weighing signal W1 at this time
And stored in the weighted time shift register. At this time, the counter tx is reset and a new count is started.

When the third piece is weighed, the value of the counter tx at that time and T1 are added to obtain the weighting time T2, and this and the weighting signal W2 are combined with the weight shift register and the weighting time. Store in shift register. The same is performed thereafter. However, if the weighing signal does not fall within the permissible value range (defined by a predetermined reference value WT, permissible upper limit deviation WU and permissible lower limit deviation WL), the same as in the first and second embodiments. Ignore it.

In this way, when N weight signals and N weight times corresponding to these weight signals are obtained, a regression line L1 is obtained by the method of least squares as shown in FIG. 8 (a). (In FIG. 8, it is assumed that a total of N weight signals from W0 to W (N-1) are within the allowable value range.)

Then, when the (N + 1) th piece is weighed, the weighing time TN is obtained in the same manner as described above. Therefore, the estimated reference value WT1 at the weighing time TN is obtained from this and the regression line L1 obtained previously. Ask for. Then, this estimated reference value W
Within the allowable value range defined by T1, the allowable upper limit deviation WU, and the allowable lower limit deviation WL, the N + 1th weighing signal W
It is determined whether N is entered, and if N is entered, WN and weighing time TN are stored in the weight shift register and the weighing time shift register.

At this time, the oldest weighing signal and weighing time are discarded, and W1 and T1 are shifted to the final stage, as shown in FIG. N + 1 within the above allowable range
If the third weighing signal WN is not input, the weighing signal WN and the weighing time TN are not stored in the weight shift register and the weighing time shift register.

When the WN and the weighting time TN are stored in the weight shift register and the weighting time shift register as described in connection with the first embodiment, overflow of the weighting time shift register is prevented. In order to save the weight, the oldest one among the stored weight times, that is, the weight time at the final stage is set to 0. In this case, T1 is subtracted from the value at each stage of the weight time shift register. This state is shown in FIG. Then, in this state, the next N + 2
The regression line L2 is calculated by the method of least squares in preparation for the weighing of the second item. Thereafter, the same operation is performed.

The processing of the CPU for performing such processing will be described in detail with reference to the flowchart shown in FIG. In this embodiment, the flag F1 for determining whether or not weighing has started. First, the weight shift register and the weighting time shift register are reset, and the flag F1 is set to 0 (step S30).

Then, it is judged whether or not it is the weighing timing (step S32). This determination can be made using the article detector and the timer provided on the carry-in side of the weighing conveyor, as described in the first embodiment. Then, at the weighing timing, it is determined whether the flag F1 is 1 (step S34). Since the flag F1 is 0 when the weighing of the first item to be weighed is started, the counter tx is set to 0.
Then, the flag F1 is set to 1 (step S36), and the weighing signal Wx is input (step S38). If the flag F1 is already 1, that is, if there are two or more items to be weighed, the weighing signal Wx is immediately input.

Then, the value of the counter tx is added to the value m0 at the first stage of the weighting time shift register, that is, the weighting time immediately before, to obtain the current weighting time Tx (step S4).
0). At the time of weighing the first item to be weighed, since the value m0 of the first stage of the weighing time shift register and the value of the counter tx are both 0, the current weighing time Tx is also 0.

Then, it is judged whether or not the regression line for estimating the reference value for the current weight is already stored (step S42). Since the regression line does not exist in the state where N total weight signals within the allowable value range are not collected yet, this weight signal wx is the reference value W set in advance.
It is determined whether T is within an allowable value range defined by the allowable upper limit deviation WU and the allowable lower limit deviation WL (step S4).
4).

When it is within the allowable value range, the non-defective product processing similar to that of the first embodiment is performed (step S46), Wx is input to the first stage of the weight shift register, and the previously obtained Tx is input to the weighting time shift register. Input in the first step (step S48),
The counter tx is reset (step S50). The counter tx is reset in order to measure the elapsed time until the next weighing time. Then, it is judged whether or not there is a stage having a value of 0 other than the final stage of the weighing time register, that is, whether N weighing signals are stored in the weight shift register 20 (step S52), and N weighings are performed. If no signal is stored, the process returns to step S32.

If the weighing signal Wx is not within the allowable value range in step S44, defective product processing similar to that of the first embodiment is performed (step S54), and step S3.
Return to 2. Therefore, when the weighing signal Wx is not within the allowable value range, the weight of the item to be weighed is not stored in the weight shift register, and its weighing time is not stored in the weighing time shift register. Moreover, since the counting of the counter tx is continued, the time until the next generation of the weighing signal within the allowable value range is measured by the counter tx.

In this way, the weighing signals falling within the N allowable value ranges are stored in the weight shift register, and the respective weighing times corresponding thereto are stored in the weighing time shift register. Then, it is determined whether the final stage of the weighted time shift register has a value other than 0 (step S56). When N weight signals are stored for the first time, the last stage is 0, and there is no possibility of overflow. Therefore, each weight signal of the weight shift register 20 and each weight time of the weight time shift register are Based on this, the regression line for estimating the reference value used at the next weighing is calculated and stored (step S58), and the process returns to step S32.

When the N + 1th item to be weighed is weighed,
The weighing signal Wx is input (step S38), the weighing time at that time is calculated (step S40), and it is determined whether the regression line is stored (step S42).
In this case, since the regression line is stored, the estimated reference value WTx at the weighing time Tx is calculated using this regression line and the weighing time Tx, and this is set as the reference value WT (step S60). Then, by using this new reference value WT, the weighing signal W within the allowable value range is obtained in step S44.
It is determined whether x is included, and if it is within the allowable value range, steps S46, S48, S50 and S52 are executed.

Then, step S56 is executed,
At this point, since the new weighing time is input to the weighing time shift register in step S48, the weighing time of the second weighing signal within the allowable value range ( In FIG. 8, T1) is stored. Therefore, the process proceeds from step S56 to step S62, and the value of each stage of each weight shift register is decreased by the value of the last stage of this weighted time shift register. This is to prevent overflow of each stage of the weighted time shift register. Then, step S58 is executed to calculate the regression line for estimating the reference value used for the next weighing, and the process returns to step S32.

By the way, in this embodiment, step S3
When it is judged that it is not the weighing timing in 2,
It is determined whether the value of the counter tx is equal to or greater than the allowable upper limit time TU (step S64), and if it does not exceed the allowable upper limit time TU, the process returns to step S64. If it exceeds, the weight shift register and the weight time shift register are reset, the counter tx is reset to 0, the flag F1 is also reset to 0, and the process returns to step S32.

This is to prevent the counter tx from overflowing, and for a long time, a weighing signal falling within the allowable value range is not obtained, and then a weighing signal falling within the allowable value range is obtained. However, the combination of the old data and the latest data may not be able to accurately represent the current trend of changes in the weight of the weighted article with a regression line.
This is to prevent this.

[0074]

As described above, in the weight sorter according to the first aspect of the present invention, the articles to be weighed are supplied to the weighing means almost every predetermined time, and the weighing means is supplied to the weighing means at each supply. A weighing signal that represents the weight of the weighing object is generated, and with this weighing signal,
The determination means compares the two boundary values that are respectively set so as to be shiftable with respect to the reference value, and determines whether or not the weighing signal is an allowable value. The weight signal and the number of times the weight signal indicates the weight of the weighted article weighed at each time are made to correspond to each other and are sequentially stored in the storage means, and each of the storage means is stored. The reference value for the next weighing is estimated by the estimating means based on the least-squares method using the heavy signal and each weighing number. That is, since the standard value is configured to be estimated using the least squares method, the estimated standard value does not cause time delay even if the physical properties of the weighted article change with time, and the estimated standard value is calculated. It is possible to capture the changing tendency of the multiple signals and prevent misselection. Moreover, if the least-squares method is used, even if each weighing signal includes an error component such as a vibration component or noise, the change tendency of the weighing signal can be estimated without being affected by the error component.

Further, in the weight sorter according to claim 2, the weight sorter according to claim 1 uses the number of times of weighing, whereas the weight sorter according to claim 1 uses the time of weighing. The same effect as the invention of.

According to the third aspect of the present invention, in the weight sorter, the container to be carried is filled into the container to be carried in approximately every predetermined time from the filling means for filling the articles to be weighed by the reference weight. The weighed articles are sequentially weighed by the weighing means, a weighing signal is generated each time the weighing is performed, and the determining means stores the weighing signal in a manner that determines whether the weighing signal is an allowable value. Means, the weighing signal determined to be the allowable value, and the weighing signal indicating whether the weighing signal is that of the weighed article weighed at which times are sequentially stored in association with each other,
Using each weighing signal and each weighing number of this storage means, the estimation means estimates the filling weight in the next filling means based on the least squares method, and the filling weight estimated by this estimation means and the above Since the filling control means controls the filling weight in the filling means on the basis of the deviation from the reference weight, the filling weight in the filling means changes according to the change in the physical properties of the article to be weighed with the passage of time and the like. Even in this case, it is possible to fill the items to be weighed by the reference weight while making corrections without time delay. Moreover, if the least squares method is used, even if each weighing signal includes an error component such as a vibration component, it is possible to estimate the change tendency of the weighing signal without being affected by the error component.

[Brief description of drawings]

1 is a flow chart of a first embodiment of a weight sorter according to the present invention.

FIG. 2 is a block diagram of the first embodiment.

FIG. 3 is a diagram showing a weighing signal, a number of weighings, and a regression line calculated using the least squares method using the weighing signal in the first embodiment.

FIG. 4 is a diagram showing a change state of the weight count shift register in the first embodiment.

FIG. 5 is a block diagram of the second embodiment.

FIG. 6 is a diagram showing a part of a flowchart of the second embodiment.

FIG. 7 is a flowchart of the third embodiment.

FIG. 8 is a diagram showing a weighting signal and a weighting time of the third embodiment, and a regression line calculated using the least squares method using these signals and a change state of the weight shift register.

FIG. 9 is an explanatory diagram of a sorting method in a conventional weight sorter.

[Explanation of symbols]

6 Weighing Conveyor 8 Load Cell (Weighing Means) 16 CPU (Estimating Means, Judging Means) 20 Weight Shift Register (Memory Means) 22 Weight Count Shift Register (Memory Means) 30 Screw Conveyor (Filling Means) 36 Motor Drive and Motor Control unit (filling control means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI G01G 11/00 G01G 11/00 H 13/24 13/24 C 13/295 13/295 (56) Reference JP-A-62- 12819 (JP, A) JP 62-138728 (JP, A) JP 5-215596 (JP, A) Actually opened 58-56923 (JP, U) JP 61-12525 (JP, B1) Japanese Patent Publication 8-20304 (JP, B2) Patent 2936752 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01G 15 / B07C 5/18 B65B 1/34 B65B 1/46 B65B 3/28 G01G 11 / G01G 13 /

Claims (3)

(57) [Claims] 1. A weighed article is supplied almost every predetermined time, and a weighing means for generating a weighing signal representing the weight of the weighed article for each supply, and a shiftable relative to a reference value. A determining unit that compares the two set boundary values with the weighing signal to determine whether the weighing signal is within an allowable value range, and a determination unit that is determined to be within the allowable value range. Storage means for sequentially storing the weight signal and the number of times of weighting indicating the weighted article for which the weighted signal has been weighed at each time, and storage means for sequentially storing the weight signal. A weight sorter comprising: an estimation means for estimating the reference value at the time of the next weighing based on the least-squares method by using the heavy signal and each weighing number. 2. A weighed article is supplied, a weighing means for generating a weighing signal representing the weight of the weighed article for each supply, and 2 set so as to be shiftable with respect to a reference value. Comparing the boundary value and the weighing signal of the individual, the determining means for determining whether the weighing signal is within the allowable value range, and the weighing signal determined to be within the allowable value range, The storage means for sequentially storing the weighting time of the weighting signal, and the storage means for sequentially storing the weighting signal of the next weighing time based on the least square method using each weighing signal and each weighing time of this storage means. A weight sorter comprising: an estimation unit that estimates the reference value. 3. A container to be carried in is sequentially weighed from the filling means for filling the object to be weighed into the container to be carried in approximately every predetermined time from the filling means. , A weighing means for generating a weighing signal representing the weight of the article to be weighed each time the weighing is performed, a determining means for determining whether or not the weighing signal is within an allowable value range, and the allowable value A storage unit that sequentially stores the weighing signal determined to be within the range and the weighing number indicating how many times the weighing signal belongs to the item to be weighed, Estimating means for estimating the filling weight in the next filling means based on the least squares method using each weighing signal and each weighing count of the storing means, and the filling weight estimated by this estimating means and the reference. A filling system for controlling the filling weight of the filling means based on the deviation from the weight. Weight sorters and means comprises.