JPH034273B2 - - Google Patents

Description

[Detailed description of the invention]

<Field to which the present invention pertains> The present invention relates to a weight sorting device. <Prior Art and Its Disadvantages> Generally, a weight sorting device has the following features as shown in FIG.
The object to be weighed W is supplied to the weighing conveyor 2 by the run-up conveyor 1, is weighed by the weighing device 3 while being conveyed by the weighing conveyor 2, and the signal from the weighing device 3 is converted into a digital signal by the A/D converter 4. This measured value is compared with a tolerance value (for example, an upper limit value and a lower limit value) set in a tolerance value setting device 5 by a comparator 6, and a selection output is output. Therefore, in the conventional weight sorting apparatus, the upper limit value and the lower limit value are set each time a variety is weighed by using the key switch 7 to the above-mentioned tolerance value setting device 5. However, with this method, when changing the type of object to be weighed, it is necessary to check and set the upper and lower limit values for that type of object each time, which is very complicated. If product types are changed frequently, there is a risk of setting errors, and the setting work requires a lot of time. Therefore, in the past, as another method, upper and lower limit values for only predetermined types are stored in the tolerance value setter 5, and when changing the type, the type number is keyed in using the key switch 7. In some cases, a method was also used to call up the upper and lower limits for the variety. However, this method is cumbersome because it is necessary to enter the product number every time the product is changed.If the product is changed frequently, input errors are likely to occur.Also, if there are many products, the set numerical values are memorized. This has the disadvantage of being expensive because it requires a large amount of memory capacity. Furthermore, in any of the above methods, the allowable value set in the allowable value setter 5 is set based on the true weight of the object, not the actual weight of the object to be weighed. However, in the above device, the timing circuit 8 extracts the output of the A/D converter 4 as a measured value at the timing when the output of the measuring instrument 3 reaches its peak value and becomes stable. Depending on the situation, the timing of stabilizing to the peak value may vary.
An error may occur between this measured value and the true weight. Also, the physical properties of the object to be measured (soft items, liquids)
In such cases, an error may occur between the actual measured value and the true weight. The temperature characteristics and linearity of the device also cause errors in the true weight. Therefore, when the upper and lower limits are set based on the true weight as described above, there is a drawback that a selection error occurs due to an error with the actual weighed value. <Objective of the present invention> The present invention solves these drawbacks, eliminates the trouble of setting or selecting tolerance values for each type of object to be weighed, and eliminates the error between the actual measured value and the true weight. It is an object of the present invention to provide a weight sorting device that does not cause sorting errors even when there is a problem. <Configuration of one embodiment of the present invention> An embodiment of the present invention will be described below based on the drawings. FIG. 2 is a block diagram showing the structure of an embodiment of the weight sorting device of the present invention. In the figure, 11 is a run-up conveyor that transports the objects to be weighed W, 12 is a weighing conveyor that transports the objects W to be weighed that are transported from the run-up conveyor 11, and 13
is a sorting conveyor for sorting the objects to be weighed W supplied by the weighing conveyor 12 according to the weighing results. 21 is a position detector that outputs a detection signal each time an object to be weighed is conveyed to the weighing conveyor 12; 22 is a timing circuit that receives the detection signal of the position signal detector 21 and outputs a timing signal after a predetermined time period; . 23 is a weighing device that sends out a weighing signal corresponding to the weight of the object to be weighed while it is being conveyed to the weighing conveyor 12; 24 is a timing circuit 22 that sequentially A/D converts the weighing signal from the weighing device 23; This is an A/D converter that sends out a measurement (digital) signal when it receives a timing signal. 25
is a gate circuit that allows an A/D-converted weighing signal to pass when an object to be weighed of a regular weight is conveyed to the weighing conveyor 12. 26 is the gate circuit 2
This is a reference weight storage device that stores the weighing (digital) signal of the object to be weighed of the normal weight passing through the reference weight storage device 5 as a reference weight. This gate circuit 25 receives an operation signal S from a switch (not shown) that is operated when weighing an object to be weighed with a regular weight, or automatically detects that an object to be weighed with a regular weight has been conveyed. A weighing signal of the object to be weighed of the normal weight is passed by a signal S from a detecting device (not shown). Reference numeral 27 denotes a tolerance setter that stores in advance a tolerance corresponding to a reference value within a predetermined range. For example, as shown in Table 1, the reference weight of the object to be weighed is
If it is 300 to 1000 grams, divide that range and
The tolerance corresponding to each divided range is determined and stored in the tolerance setter 27 in advance.

[Table] 28 is an arithmetic unit that calculates the upper limit value and the standard weight for sorting by adding and subtracting the tolerance corresponding to the range of the above-mentioned reference weight from the reference weight stored in the reference weight storage unit 26. This is to obtain the lower limit value. For example, if the reference weight stored in the reference weight memory 26 is 995 grams, the tolerance corresponding to this weight is +10 and -5 grams, so the upper limit is
Calculate 995 + 10 to get 1005 grams, lower limit is 995
Calculate -5 to get 990 grams. 29 is the upper limit value calculated by the calculator 28;
This is a tolerance value storage device that stores a lower limit value. 30 is
The weighing signal from the A/D converter 24 for the object to be weighed that is transported after the reference weight item is compared with the tolerance values (upper limit value, lower limit value) stored in the tolerance value storage device 29, and the weight is determined. This is a comparator that makes a judgment. 31 is a control circuit that receives a determination signal obtained by the comparator 30 and controls the sorting operation of the sorting conveyor 13, and 32 is a display that displays the weight value. <Operation of the embodiment> In the weight sorting device configured as described above, before feeding a large number of objects to be weighed W to be sorted, when objects to be weighed of the regular weight prepared in advance are conveyed, the weighing device The measurement signal is sent from 23 to the A/D converter 24, and the measurement value when receiving the timing signal from the timing circuit 22 is a gate circuit that is opened by the signal from the switch or the signal from the detection device. 25, and is stored in the reference weight storage 26 as a reference value. When the reference value is stored, the calculator 28 retrieves the tolerance corresponding to this reference value from the tolerance setter 27 set as shown in Table 1, and stores the reference weight set in the reference weight memory 26. and the selected tolerance to calculate the upper limit and lower limit, and send the results to the tolerance storage 29, which stores them. Therefore, when the object to be weighed W to be sorted is conveyed sequentially following the object to be weighed of the normal weight, the weighing device 2
3. The weighing signal passed through the A/D converter 24 is sent to the comparator 3.
0 is compared with the upper limit value and lower limit value stored in the tolerance setter 27, and the weight is selected,
Based on this sorting output, the control circuit 31 sorts out the objects to be weighed that have been conveyed to the sorting conveyor 13. Next, when changing the type of object to be weighed, transport one of the new type of object to be weighed with a pre-prepared standard weight, and open the gate circuit 26 with the signal S from the switch or detection device. Instead of the previous reference weight of the product, the reference weight of the new product is stored in the reference weight storage 16, and the corresponding upper and lower limit values are similarly calculated in the calculator 28 and stored in the tolerance storage 29. Then, the objects to be weighed to be sorted are sequentially conveyed after the objects to be weighed of the normal weight, and the same sorting operation is performed thereafter. In addition, in the above example, the tolerance was directly set as a value in grams as shown in Table 1, but this means that the tolerance with respect to the reference weight is expressed as a percentage as shown in Table 2, and this is calculated as the tolerance. Set on the setting device 27,
In the arithmetic unit 28, the upper limit value and the lower limit value may be set by multiplying the reference value by a percentage corresponding to the reference value, and adding and subtracting the result from the reference value.

[Table] <Effects of the present invention> As is clear from the above explanation, in the weight sorting device of the present invention, the allowable value that is the standard for weight sorting is
Settings can be made automatically by simply transporting the object to be weighed of the correct weight, eliminating the need for the complicated work of checking and setting tolerances each time a product type is changed or setting the product number. This dramatically improves the efficiency of sorting work and eliminates the problem of setting errors. Furthermore, since there is no need to set permissible values for each product type, the number of memories used is small and the cost is low. Further, in the weight sorting device of the present invention, the allowable value is calculated based on the actual weighing result of the object to be weighed of the normal weight. Therefore, even if there is an error in the measurement of the object to be weighed from the true weight due to the length, shape, physical properties, temperature properties, etc. of the object to be measured, the true weight can be used as the standard as before. Because there is no
No sorting errors occur.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional weight sorting device, and FIG. 2 is a block diagram showing an embodiment of the present invention. 11... Run-up conveyor, 12... Weighing conveyor, 13... Sorting conveyor, 21... Position detector, 22... Timing circuit, 23... Weighing device,
24...A/D converter, 25...gate circuit, 2
6...Reference weight memory device, 27...Tolerance setting device,
28...Arithmetic unit, 29...Tolerance value storage device, 30...
... Comparator, 31 ... Control circuit.

Claims (1)

[Scope of Claims] 1. A weighing conveyor that conveys an object to be weighed: A weighing device that weighs an object being transported by the weighing conveyor and outputs a weighing signal; A/A weighing signal from the weighing instrument; an A/D converter that performs D conversion; a setting device in which a tolerance or an allowable ratio corresponding to the weight is set in advance; a reference weight memory that stores the output as a reference weight; a reference weight stored in the reference weight memory;
a calculator that calculates an allowable weight corresponding to the reference weight based on the tolerance or allowable ratio of the setting device corresponding to the reference weight; storing the allowable weight obtained by the calculator; a tolerance storage device; a comparator that compares the tolerance weight stored in the tolerance storage device with the measured value from the A/D converter to generate a sorting output; A weight sorting device characterized in that the value can be obtained by transporting an object to be weighed of a regular weight.