JPH045129B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic weight sorting device that sorts a plurality of articles according to their weight, and particularly relates to an automatic weight sorting device that outputs a warning signal when the weight of articles becomes defective at a certain rate. Regarding a sorting device.

In the quality inspection process of a manufacturing factory, a weight standard value is set for the manufactured articles, and overweight and lightweight items that are outside the predetermined weight range with respect to this standard value are classified as defective items and sent to a sorting machine. It is excluded. Some of these automatic weight sorting devices that sort out good products and eliminate defective products are equipped with a defect detection circuit that outputs a warning signal when the number of articles determined to be defective exceeds a predetermined allowable limit. There is. When this warning signal is output, the supervisor inspects, repairs, and adjusts the manufacturing equipment, etc.

In a defect detection circuit of a conventional automatic weight sorting device, a permissible number of consecutive articles that are determined to be defective is generally set as a condition for outputting the warning signal. That is, the setting is such that a warning signal is output when the number of articles exceeding the above-mentioned allowable limit is consecutively determined to be defective.

However, with an automatic weight sorting device configured in this way, taking into account variations in weight during the manufacture of articles, it is possible to , there is a risk that detection of the change phenomenon may be delayed, and inspection, repair, and adjustment of the manufacturing equipment may be delayed, resulting in a problem that a large number of defective products will be manufactured.

In addition, in another automatic weight sorting device, after measuring the weight of all the articles equivalent to one lot during manufacturing, the number of defective articles included therein is detected and the number of defective articles is set in advance. Some devices output a warning signal when the specified limit number is exceeded. However, if the device has such a defect detection method, the warning signal will not be output until the measurement of all items in one lot is completed.
When the weight changes gradually as in the above example, the change cannot be detected midway through, and there is a risk that a large number of defective articles will be manufactured as in the above example.

Furthermore, if the average value of the weight of a certain number of items is always calculated, it is possible to always know the average weight value of the items, but the average value hardly changes and the variation value can be reduced. If only the indicated standard deviation increases, no warning signal is output and a large number of defective products will still be manufactured.

The present invention has been made based on these circumstances, and its purpose is to constantly detect the number of defective articles in a constant amount of weight data, even if the weight of the article gradually changes. It is an object of the present invention to provide an automatic weight sorting device that can immediately detect the change even if such a change occurs, can minimize the amount of defective articles manufactured, and can improve the yield of manufactured articles.

The present invention will be explained below using the drawings. FIG. 1 is a schematic configuration diagram showing an automatic weight sorting device according to an embodiment of the present invention.

In the figure, reference numeral 1 denotes a carry-in conveyor for carrying in articles 2 manufactured continuously by a manufacturing device (not shown), and a measuring device 3 for measuring the weight of the articles 2 is installed adjacent to the carrying direction of this carry-in conveyor 1. has been done.
This weighing device 3 has a built-in weighing conveyor 4 on which articles 2 carried in by the carrying-in conveyor 1 are placed. Further, an unloading conveyor 5 for unloading the weighed articles 2 is installed adjacent to this weighing device 3, and the weighing device 3 of this unloading conveyor 5 is
A sorting machine 6 is attached to the side for sorting the measured articles 2 into three stages, ie, excessive weight, correct weight, and light weight, according to their weight values. Furthermore, a phototube 7 is installed on the carry-in conveyor 1 to set the timing for measuring the weight of the article 2 placed on the weighing conveyor 4.

FIG. 2 shows a control block diagram of the automatic weight sorting apparatus having the above structure. That is, the output signal of the scale 3 for measuring the weight of each article 2 is amplified by the amplifier 8 and input to the A/O converter 9. This A/
A measurement timing signal from a timer circuit 10 controlled by the trigger signal of the phototube 7 is input to the D converter 9 . As a result, the digital weight data of article 2 measured at the optimum timing is transferred to the A/D
The signal is sent from the converter 9 to a determination circuit 12 composed of a display 11 and a comparator. This judgment circuit 1
2 receives setting data from a weight setting device 13 that sets the weight value of the article 2 to the predetermined values of excessive weight, correct weight, and light weight with respect to the reference weight.
However, this judgment circuit 12 judges the weight data from the A/D converter 9 as excessive weight, correct weight, or light weight based on the setting data from the weight setting device 13, and sends the result to the sorting machine 6 as a judgment signal. At the same time, the excessive amount and the light amount are collectively treated as a defective signal, and the correct amount is treated as a good signal and sent to the defect detection circuit 14.

The defect detection circuit 14 is configured as shown in FIG. 3, for example. That is, the judgment signal s of a good signal or a bad signal from the judgment circuit 12 is inputted to, for example, a 10-digit shift register 16 via an input gate 15. This judgment signal s is 0 when it is a good signal,
It is set to 1 when there is a defective signal. Further, a clock signal c synchronized with the measurement timing is input to the clock input terminal of the shift register 16. Each of the ten output signals of the shift register 16 is input to an analog switch circuit 17 as a measuring means for counting the number of one level defective signals included in the ten determination signals s stored in the shift register 16. This analog switch circuit 17 is provided with ten switches 18 as shown in the figure, and each switch 18 is turned on or off depending on the value of 1 or 0 outputted from each output terminal of the shift register 16.
Controlled off. In the embodiment, 1 corresponds to on and 0 corresponds to off. One end of each switch 19 is connected to one terminal of each switch 18, and the other end of each switch 19 is commonly connected to a voltage supply terminal 20 of a reference voltage Vf1.
These switches 19 and voltage supply terminals 20 constitute a first setting device 21 for setting the number N of articles to be continuously measured by the measuring instrument 3. On the other hand, the other terminal of each switch 18 is connected to a resistor 2.
2 to the input terminal of an adder 23, and the output terminal of this adder 23 is connected to one input terminal of a comparator 24. Note that adder 2
A resistor 25 is connected between the input and output terminals of 3. The other input terminal of the comparator 24 has the first
Common to one end of each of the ten switches 27 in the second setting device 26 that sets the allowable limit number a of the number of one-level defective signals included in the judgment signal s of the consecutive number N set in the setting device 21 of It is connected to the. The other ends of each switch 27 are connected to each other through resistors 28 having the same value, and one of the resistors 28 located at both ends is grounded via a resistor 29, and the other end is connected to the voltage of the reference voltage Vf2. It is connected to the supply terminal 30. Furthermore, the output terminal of the comparator 24 is connected to the input terminal of an output circuit 31 that outputs a warning signal k.

Next, the operation of the automatic weight sorting device configured as described above will be explained. First, the first setting device 21
The consecutive number N is set in . Specifically, the first to Nth switches 19 are turned on. Third
In the figure, N=10 is set. Therefore, the reference voltage Vf1 is applied to one end of all the switches 18 of the analog switch circuit 17. Next, the second setter 26 sets the allowable limit number a of the number of defective signals included in the number N of consecutive signals. In this case, it is sufficient to turn on the a-th switch 27 from the bottom. In the embodiment, a=3 is set. Each resistor 2 inserted between each switch 27
Since the values of 8 are equal, a voltage proportional to the set number a is input to one input terminal of the comparator 24.

When the weight of the articles 2 that are continuously carried in on the carry-in conveyor 1 is sequentially measured by the measuring device 3, the articles 2 after the measurement are sorted by the sorter 6 into three categories: excessive weight, correct weight, and light weight. The judgment signal s of each article 2 is sorted and output from the judgment circuit 12.
are sequentially applied to the input gate 15 of the defect detection circuit 14. The determination signal s is sequentially stored in the shift register 16 each time the clock signal c synchronized with the measurement timing is input to the clock input terminal of the shift register 16. the result,
The ten latest judgment signals s are always stored in order in the ten storage areas of the shift register 16. Therefore, in the analog switch circuit 17, a number of switches 18 corresponding to the number of defective signals included in the ten judgment signals s stored in the shift register 16 are turned on. As a result, adder 2
3 outputs a voltage corresponding to the number of defective signals.
This voltage is compared by the comparator 24 with the voltage corresponding to the allowable limit number a from the second setter 26. Then, if the voltage from the adder 23 is higher, 1
The level signal is applied to the output circuit 31, and the output circuit 31 outputs a warning signal k. In the state shown in FIG. 3, the allowable limit number a=3 and four defective signals are stored in the shift register 16, so the output circuit 31 outputs a 1-level warning signal k.

Next, suppose that an article 2 whose weight gradually increases over time as shown in FIG. 4 is measured using this automatic weight sorting device. In the figure, black circles indicate defective products, and white circles indicate good products. moreover,
Assume that the number of continuous measurements of article 2 is N=10, and the allowable limit number a=5. As shown in the figure, the number of defects is 2 when the 10th article 2 is measured, so no warning signal k is output. In this way, the number of defects is 5 when the 17th item is measured.
As a result, the output circuit 31 outputs a warning signal k. By the way, if the system is like a conventional device that outputs a warning signal when the number of consecutive defective items reaches 5, the warning signal will be output when the 25th item is measured, as shown by the broken line in the figure. be done. When the weight changes gradually in this way, the change is immediately detected and a warning signal k is output, so the supervisor can promptly inspect, repair, or adjust the manufacturing equipment, etc. based on the warning signal. Therefore, the amount of defective articles manufactured can be minimized, and the yield of manufactured articles can be improved.

In addition, with such a defect detection circuit 14, even if the average value hardly changes and only the standard deviation indicating the dispersion value increases, when the number of defective items reaches the allowable limit number a, the warning signal k is immediately sent. is output, so the same effect as above can be obtained.

Furthermore, since the number N of articles 2 to be continuously measured by the scale 3 can be arbitrarily set using the first setting device 21, there is no need to wait for the measurement of all articles 2 in one lot to be completed, and a large number of defective articles can be easily measured. We cannot manufacture products without knowing this.

FIG. 5 is a block diagram showing the defect detection circuit 14 of another embodiment of the automatic weight sorting apparatus of the present invention. The determination signal s from the determination circuit 12 is input to the variable length shift register 42 via the input gate 41. In addition to the clock signal c synchronized with the measurement timing at the clock input terminal of the variable length shift register 42, a clock signal d whose frequency is about two orders of magnitude higher than this clock signal c is input to the input gate 43.
Input via . Further, a setting signal from a first setting device 44 consisting of a digital switch for setting the amount of storage area, that is, the number N of consecutive articles 2 is inputted to the variable length shift register 42. Further, a determination signal outputted from the output terminal of the variable length shift register 42 is inputted to the input gate 41. The setting signal from the first setting device 44 is sent to the preset counter 4 which controls the input gate 43.
It is also input to the control terminal No. 5. The clock signal d is input to the input terminal of the preset counter 45.

The determination signal output from the output terminal of the variable length shift register 42 is sent to a counter 46 as a measuring means for counting the number of defective signals. The data on the number of defective signals counted by the counter 46 is input to one input terminal of a comparator 47, and the data on the number of defective signals included in the consecutive number N judgment signals is input to one input terminal of the comparator 47. Setting data from a second setter 48 consisting of a digital switch for setting the allowable limit number a is input. The output terminal of the comparator 47 is connected to the input terminal of an output circuit 49 that outputs a warning signal k.

In such a defect detection circuit 14, the number N of continuous measurements of the article 2 and the allowable limit number a are first set in the first setter 44 and the second setter 48. Then, the number of determination signals that can be stored in the variable length shift register 42 is set to N. Further, the count number of the preset counter 45 is also set to N. When one judgment signal s is input to the input gate 41, it is input to the variable length shift register 42 in synchronization with the clock signal c. At the same time, N high frequency clock signals d set by the preset counter 45 are applied to the clock input terminal of the variable length shift register 42. As a result, the N judgment signals already stored are output at once to the output terminal of the variable length shift register 42, and the number of 1-level defective signals included in this judgment signal is counted by the counter 46. . Note that the judgment signals outputted all at once are inputted again to the variable length shift register 42 via the input gate 41, so that the latest N judgment signals are always stored in the variable length shift register 42. There is. The number of defective signals outputted from the counter 46 is compared with the allowable limit number a from the second setter 48 in a comparator 47, and if the number of defective signals is larger, the comparator 47
7 outputs a 1 level signal. the result,
A warning signal k is output from the output circuit 49.

Even in an automatic weight sorting device having such a configuration, when the number of defective signals included in the determination signals of the number N of consecutive measurements of the article 2 reaches the allowable limit number a, a warning signal k is immediately output. Therefore, it is possible to obtain the same effects as in the embodiment described above.

FIG. 6 shows a defect detection circuit 14 according to yet another embodiment of the present invention. In the defect detection circuit of this embodiment, a divider 50 is inserted between a counter 46 and a comparator 47 that measure a defect signal included in the judgment signal from the variable length shift register 42. Setting data from the first setting device 44 is input to this calculator 50 . And divider 5
0, the ratio of the number of defective signals included in the continuously measured number N of determination signals s is calculated and outputted to the comparator 47. On the other hand, the second setting device 51 has the number of consecutive measurements N.
A permissible limit value b of the ratio of the number of defective signals included in the judgment signals s is set, and a comparator 47 compares the ratio from the divider 50 and the ratio b from the second setter 51. The result is then output to an output circuit 49.

If the automatic weight sorting device has the defect detection circuit 14 configured in this way, the warning signal k will be output when the occurrence rate of defective articles 2 reaches the preset allowable limit ratio b. The same effects as in the embodiment described above can be obtained.

FIG. 7 is a control block diagram showing an automatic weight sorting apparatus according to still another embodiment of the present invention. The same parts as in FIG. 2 are given the same reference numerals. In this embodiment, the determination signal s output from the determination circuit 12 is input to the signal distributor 52. This signal distributor 52 sequentially distributes the continuously input determination signal s to the three defect detection circuits 14a, 14b, and 14c in the order of input. Each defect detection circuit 14a, 14 receives every third judgment signal.
b and 14c are the aforementioned defect detection circuits 14, respectively.
has the same configuration as, and when the number of defective signals included in each input judgment signal reaches the allowable limit number a,
Each outputs a warning signal k.

The automatic weight sorting device having such a configuration can maximize its effectiveness by installing it, for example, in a quality inspection process where three manufacturing devices simultaneously manufacture the same product. An example of its application is shown in FIG. In this figure, the number N of continuous measurements of the article 2 is set to 6, and the allowable limit number a is set to 3. Since the number n of defect detection circuits installed in the embodiment is 3, when the data group of the judgment signal s as shown in the upper part of FIG. are respectively the 8th
Each defective signal is detected as shown in A, B, and C at the bottom of the figure. That is, during the measurement period from the 1st to the 30th, the failure detection circuits 14a and 14b do not output the warning signal k, and only the failure detection circuit 14c outputs the warning signal k when the weight of the 21st article 2 is measured. Output.

Therefore, when the supervisor confirms the warning signal k of the defect detection circuit 14c, he inspects the manufacturing device corresponding to the defect detection circuit 14c among the three manufacturing devices,
All you have to do is repair and adjust. Therefore, the manufacturing equipment producing defective products can be immediately identified, and inspection, repair, and adjustment can be carried out promptly, so that the same effects as in the embodiments described above can be obtained.

It should be noted that the present invention is not tested by the above-mentioned embodiments. Defective detection circuit 14 in FIG.
The number of a, 14b, and 14c installed may be arbitrarily changed depending on the manufacturing equipment and the like.

As described above, according to the present invention, the quantity of defective articles in a certain amount of weight data is constantly detected, and when this quantity reaches a permissible limit value, a warning signal is output. Therefore, even if the weight of the article gradually changes, the change can be detected immediately, the amount of defective articles manufactured can be minimized, and the yield of manufactured articles can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an automatic weight sorting device according to an embodiment of the present invention, FIG. 2 is a control block diagram of the same sorting device, FIG. 3 is a block diagram of a defect detection circuit of the same sorting device, and FIG. 4 is a diagram for explaining the effect of the same sorting device, FIGS. 5 and 6 are block diagrams of a defect detection circuit of an automatic weight sorting device according to another embodiment of the present invention, and FIG. 7 is a diagram for explaining the effect of the same sorting device. FIG. 8 is a control block diagram showing an automatic weight sorting device according to another embodiment, and is a diagram for explaining the effect of the sorting device shown in FIG. 7. 2... Goods, 3... Weighing device, 6... Sorting machine, 9
... A/D converter, 12 ... Judgment circuit, 13 ...
Weight setting device, 14, 14a, 14b, 14c...
Defective detection circuit, 16...Shift register, 17...
...Analog switch circuit (measuring means), 21, 4
4...First setter, 24, 47...Comparator, 2
6, 48, 51... second setter, 31, 49...
...Output circuit, 42...Variable length shift register, 4
5...Preset counter, 46...Counter,
50...Divider, 52...Signal splitter.

Claims (1)

[Claims] 1. A measuring instrument that sequentially measures the weight of a plurality of articles;
a determination circuit that determines the weight of each article measured by the weighing device into three predetermined levels of excessive weight, correct weight, and light weight relative to a reference weight; based on a determination signal output from the determination circuit; a sorting machine that sorts the articles into the three stages; and a defect detection circuit that outputs a warning signal when the number of articles determined to be defective for one or both of the excessive quantity and light weight in the judgment circuit reaches a permissible limit number. In an automatic weight sorting device, the defect detection circuit includes: a first setting device that sets the number of consecutive articles to be continuously measured by the weighing device; and a first setting device that sequentially stores determination signals output from the determination circuit. a memory; a measuring means for measuring the number of defective signals included in the consecutive number of determination signals stored in the memory; and a second setting for setting an allowable limit number of defective signals included in the consecutive number of determination signals. An automatic weight sorting device characterized by comprising: a device for measuring weight; and an output device for outputting a warning signal when the measuring device measures the permissible limit number. 2. The automatic weight sorting device according to claim 1, wherein the determination circuit outputs a defective signal only when the weight of each article is determined to be either overweight or light. 3. A measuring instrument that sequentially measures the weight of multiple items;
a determination circuit that determines the weight of each article measured by the weighing device into three predetermined levels of excessive weight, correct weight, and light weight relative to a reference weight; based on a determination signal output from the determination circuit; a sorter that sorts the articles into the three stages; a signal distributor having a plurality of output terminals that outputs the determination signal output from the determination circuit every predetermined number; each output of the signal distributor. a plurality of defect detection circuits that receive judgment signals output from the terminals and output a warning signal when the number of defective determinations of one or both of the excessive amount and light weight in the judgment circuit reaches a permissible limit number; In automatic weighing equipment equipped with:
Each of the defect detection circuits includes a first setter that sets the number of consecutive articles to be sent from the signal distributor to the defect detection circuit; a memory that sequentially stores determination signals output from the determination circuit; a measuring means for measuring the number of defective signals included in the consecutive number of determination signals stored in the memory; and a second measuring device for setting an allowable limit number of defective signals included in the consecutive number of determination signals.
An automatic weight sorting device comprising: a setting device; and an output means for outputting a warning signal when the measuring means measures the allowable limit number. 4. The automatic weight sorting device according to claim 3, wherein the determination circuit outputs a defective signal only when the weight of each article is determined to be either overweight or light.