JP5100566B2 - Combination weighing device - Google Patents

Description

  The present invention relates to a combination weighing device.

  In a general combination weighing device, an allowable weight range is set based on a target weight value and an upper limit weight value of an article, and among the plurality of weighing hoppers storing the article, the target is the most within the allowable weight range. A combination of weighing hoppers that achieves a total weight value close to the weight value is selected, and an article is discharged from the weighing hopper according to the combination.

  At that time, in order to prevent a decrease in weighing accuracy, the total number of weighing hoppers that store articles is a predetermined number or more, that is, the total number of weighing hoppers that are candidates for combination is a predetermined number or more, It may be set as an additional condition.

  In Patent Document 1 below, an allowable lower limit value and an allowable upper limit value are set for the number of weighing hoppers to be combined, and a plurality of weighing hoppers that are greater than or equal to the allowable lower limit value and lower than or equal to the allowable upper limit value are used. The number of weighing hoppers to be combined by selecting a combination of weighing hoppers whose total weight falls within the prescribed allowable weight range and increasing the allowable upper limit value when the prescribed fractional rate or defective rate is large A combination weighing device is disclosed that increases.

Japanese Patent No. 2925276

  If the above additional conditions are set, the device will continue until more than a predetermined number of weighing hoppers store articles even if there is a combination that achieves a total weight value within the allowable weight range. It will be in a standby state. Therefore, the operation rate is reduced.

  On the other hand, even if the above additional conditions are satisfied, if there is no combination that realizes the total weight value within the allowable weight range, an operation of increasing the upper limit weight value is also conceivable. This increases the operating rate, but greatly reduces the weighing accuracy.

  Alternatively, when there is a combination that realizes the total weight value within the allowable weight range, an operation of ignoring the additional condition may be considered. This increases the operating rate, but there is a possibility that only a combination close to the upper limit weight value may be selected. In this case, the weighing accuracy is also lowered.

  The present invention has been made in view of such circumstances, and an object thereof is to obtain a combination weighing device that can improve the operation rate while avoiding a decrease in weighing accuracy.

  The combination weighing device according to the first aspect of the present invention includes a plurality of weighing hoppers that temporarily store articles to be weighed, a weighing unit that measures the weight of articles stored in each of the weighing hoppers, Control means for controlling the discharge of articles from each of the weighing hoppers based on the weighing results of the plurality of weighing means, with respect to the weight value of the articles, a target value, a first upper limit value greater than the target value, A second upper limit value that is greater than the target value and smaller than the first upper limit value is set, and the control means is a combination of the weighing hoppers that realizes a weight value that is greater than or equal to the target value and less than or equal to the first upper limit value. And when the first condition that the total number of the weighing hoppers storing the articles is a predetermined number or more is discharged, the articles are discharged from the weighing hopper according to the combination, and the first condition Meet If not, regardless of the total number of the weighing hoppers storing articles, the second condition that there is a combination of the weighing hoppers that realizes a weight value that is greater than the target value and less than or equal to the second upper limit value is satisfied. In this case, the article is discharged from the weighing hopper according to the combination.

  According to the combination weighing device according to the first aspect, when the first condition is not satisfied, the control means has a weight not less than the target value and not more than the second upper limit value regardless of the total number of weighing hoppers storing the article. When the second condition that there is a combination of weighing hoppers that realizes the value is satisfied, the article is discharged from the weighing hopper according to the combination. As described above, when the first condition is not satisfied, the operating rate is improved by removing the condition regarding the total number of the weighing hoppers storing the articles. In this case, the use of the second upper limit value that is stricter than the first upper limit value can prevent the measurement accuracy from being lowered.

  In the combination weighing device according to the second aspect of the present invention, in particular, in the combination weighing device according to the first aspect, the second upper limit value is set as a value of a certain ratio with respect to the first upper limit value. It is what.

  According to the combination weighing device according to the second aspect, the second upper limit value is set not as a weight value but as a value of a certain ratio with respect to the first upper limit value. Accordingly, it is not necessary for the operator to re-enter the second upper limit value every time the first upper limit value is changed, and the second upper limit value can be automatically updated in accordance with the change of the first upper limit value, thereby reducing the labor of the operator. Is done.

  According to the present invention, it is possible to improve the operation rate while avoiding a decrease in measurement accuracy.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the element which attached | subjected the same code | symbol in different drawing shall show the same or corresponding element.

  1 and 2 are a top view and a front view, respectively, schematically showing the overall configuration of the combination weighing device 1 according to the embodiment of the present invention. As shown in FIGS. 1 and 2, the combination weighing device 1 includes a plurality of (in this example, 10) heads H (H1 to H10). Each head H has a supply trough M (M1 to M10), a pool hopper P (P1 to P10), and a weighing hopper W (W1 to W10). For example, the head H1 has a supply trough M1, a pool hopper P1, and a weighing hopper W1.

  In each head H, the pool hopper P is disposed below the front end of the supply trough M, and the weighing hopper W is disposed below the pool hopper P. As shown in FIGS. 1 and 2, the pool hoppers P1 to P10 are arranged in a straight line. Similarly, as shown in FIG. 2, the weighing hoppers W1 to W10 are arranged in a straight line. That is, in the combination weighing device 1, the plurality of heads H1 to H10 are arranged in parallel so that the plurality of pool hoppers P1 to P10 and the plurality of weighing hoppers W1 to W10 are arranged in a straight line. That is, the combination weighing device 1 is a linear weighing type (or parallel arrangement type) combination weighing device.

  As shown in FIG. 2, a transport conveyor 20 is disposed below the weighing hoppers W1 to W10. A discharge chute 21 is disposed below one end (right end in FIG. 2) of the conveyor 20. The bottom surface of each pool hopper P is defined by a gate that is opened and closed by each gate driving device GP (GP1 to GP10) (see FIG. 4). Similarly, the bottom surface of each weighing hopper W is defined by a gate that is opened and closed by each gate driving device GW (GW1 to GW10) (see FIG. 4).

  FIG. 3 is a cross-sectional view showing a cross-sectional structure of the combination weighing device 1 with respect to the position of the head H6. As shown in FIGS. 1 and 3, the combination weighing device 1 includes a plurality (five in this example) of auxiliary supply troughs N (N1 to N5) arranged upstream of the supply trough M. As shown in FIG. 1, the auxiliary supply trough N1 corresponds to the supply troughs M1 and M2, the auxiliary supply trough N2 corresponds to the supply troughs M3 and M4, and the auxiliary supply trough N3 corresponds to the supply troughs M5 and M6. The supply trough N4 corresponds to the supply troughs M7 and M8, and the auxiliary supply trough N5 corresponds to the supply troughs M9 and M10.

  As shown in FIG. 3, the auxiliary supply trough N3 is disposed in a slightly tilted posture. The same applies to the other auxiliary supply troughs N1, N2, N4, N5. The supply trough M is arranged in a posture that is more gently inclined forward than the auxiliary supply trough N.

  An electromagnetic feeder X6 for vibrating the supply trough M6 is attached to the bottom surface of the supply trough M6. Further, an electromagnetic feeder Y3 for vibrating the auxiliary supply trough N3 is attached to the bottom surface of the auxiliary supply trough N3. Similarly for the other supply troughs M1 to M5, M7 to M10 and the other auxiliary supply troughs N1, N2, N4, and N5, the bottom of each supply trough M (M1 to M10) is provided with an electromagnetic feeder X (X1 to X10). ), And electromagnetic feeders Y (Y1 to Y5) are attached to the bottom surfaces of the auxiliary supply troughs N (N1 to N5), respectively.

  The weighing hopper W6 is connected to weighing means such as a load cell R6 for weighing the articles stored in the weighing hopper W6. Similarly for the other weighing hoppers W1 to W5 and W7 to W10, the load cells R (R1 to R10) are connected to the weighing hoppers W (W1 to W10), respectively.

  FIG. 4 is a block diagram showing the configuration of the control system of the combination weighing device 1. The control device 30 such as a CPU is connected to a storage unit 31 such as a ROM or a RAM. Further, the control device 30 is connected to the electromagnetic feeders X1 to X10, the electromagnetic feeders Y1 to Y5, the gate driving devices GP1 to GP10, the gate driving devices GW1 to GW10, the load cells R1 to R10, and the transport conveyor 20.

  A target weight value C0, a first allowable error value C1, and a second allowable error value C2 relating to the total weight of articles to be weighed are preset and stored in the storage unit 31. The target weight value C0 is a lower limit weight value of a good product. A product in which the total weight of the articles is less than the target weight value C0 is a defective product.

  The first allowable error value C1 is a parameter that defines the upper limit weight value (first upper limit value) of a good product. The weight value of the maximum allowable error from the target weight value C0 is set as the first allowable error value C1. A product in which the total weight of the articles exceeds the first upper limit C0 + C1 is a defective product. The first upper limit value C0 + C1 can be stored in the storage unit 31 instead of the first allowable error value C1.

  The second allowable error value C2 is a parameter that defines an upper limit weight value (second upper limit value) that is larger than the target weight value C0 and smaller than the first upper limit value C0 + C1. The second allowable error value C2 is set as a value of a predetermined ratio with respect to the first allowable error value C1, such as “50% of the first allowable error value C1” or “40% of the first allowable error value C1”. The Note that the second upper limit value C0 + C2 may be stored in the storage unit 31 instead of the second allowable error value C2. A product in which the total weight of the articles is not less than the target weight value C0 and not more than the second upper limit value C0 + C2 is a product with high weighing accuracy.

  Further, the minimum number of heads HT for determining whether or not the weighing is an appropriate weighing is set in advance and stored in the storage unit 31. In the following example, the case where the minimum number of heads HT is set to 7 will be described.

  FIG. 5 is a flowchart showing a flow of operations of the combination weighing device 1. Hereinafter, the operation of the combination weighing device 1 will be described with reference to FIGS.

  Articles such as food to be weighed are put into the upstream end of the auxiliary supply trough N. The article is conveyed from upstream to downstream on the trough surface of the auxiliary supply trough N that is vibrated by the electromagnetic feeder Y. Here, the control device 30 can drive all of the electromagnetic feeders Y1 to Y5 simultaneously, and can also select and drive any one of the electromagnetic feeders Y1 to Y5.

  The article is discharged from the downstream end portion of the auxiliary supply trough N being vibrated and supplied to the upstream end portion of the corresponding supply trough M. Thereafter, the article is conveyed from upstream to downstream on the trough surface of the supply trough M that is vibrated by the electromagnetic feeder X. Here, the control device 30 can drive all of the electromagnetic feeders X1 to X10 simultaneously, and can also select and drive any one of the electromagnetic feeders X1 to X10.

  The article is discharged from the tip of the supply trough M that is being vibrated. The articles discharged from the supply trough M are supplied to the corresponding pool hopper P and temporarily stored in the pool hopper P. When the gate driving device GP opens the gate of the pool hopper P under the control of the control device 30, the articles stored in the pool hopper P are discharged. The articles discharged from the pool hopper P are supplied to the corresponding weighing hopper W and temporarily stored in the weighing hopper W.

  In step S <b> 1 of FIG. 5, the weight of the article is weighed by the corresponding load cell R with respect to the weighing hopper W storing the article. Weight data related to the result of weighing by each load cell R is input to the control device 30.

  Next, in step S <b> 2, the control device 30 performs a combination calculation based on the weight data input from the load cell R. That is, the weighing hoppers W that store articles are variously combined, and weight data relating to each combination is added.

  Next, in step S3, the control device 30 determines whether or not an appropriate combination is established. That is, the control device 30 refers to the target weight value C0 and the first allowable error value C1 stored in the storage unit 31, so that the total weight of the articles is equal to or greater than the target weight value C0 and the first upper limit value C0 + C1. The combination of the weighing hoppers W is searched.

  If the combination is established (that is, if the result of determination in step S3 is “YES”), then in step S4, control device 30 determines whether the number of effective heads is equal to or greater than the predetermined number of heads. To do. That is, the control device 30 refers to the minimum number of heads HT stored in the storage unit 31, and the number of weighing hoppers W contributing to the weighing is the number of heads represented by the minimum number of heads HT (in this example, 7 heads) or more is determined. Here, for the head H whose weight data input from the load cell R is not zero, the weighing hopper W of the head H contributes to the weighing. That is, out of all the weighing hoppers W1 to W10, if the number of weighing hoppers W storing articles is 7 or more, the number of effective heads is 7 or more.

  If the number of effective heads is 7 or more (that is, if the result of determination in step S4 is “YES”), then in step S5, the control device 30 corresponds to the weighing hopper W related to the established combination. The gate driving device GW is caused to open the gate of the corresponding weighing hopper W. As a result, the articles stored in the weighing hopper W related to the established combination are discharged from the weighing hopper W as good products. If there are a plurality of established combinations, the combination with the smallest total weight of the articles is selected.

  The articles discharged from the weighing hopper W are supplied onto the conveyor 20. The control device 30 drives the transport conveyor 20 in the forward rotation direction (right rotation direction in FIG. 2). Thereby, the articles on the conveyor 20 are sequentially sent to the discharge chute 21 and discharged from the combination weighing device 1 through the discharge chute 21 toward downstream equipment such as a packaging machine.

  Next, in step S6, it is determined whether or not all work has been completed. When all the operations are completed (that is, when the result of determination in step S6 is “YES”), the process ends. On the other hand, when all the operations are not completed (that is, when the result of determination in step S6 is “NO”), the process returns to step S1.

  If an appropriate combination is not established in step S3 (that is, if the result of determination in step S3 is “NO”), then in step S7, the control device 30 determines whether or not additional supplies can be supplied. Determine whether. That is, it is determined whether there is a weighing hopper W that does not store articles. The control device 30 determines that the weighing hopper W corresponding to the load cell R does not store articles when the weight data input from the load cell R is zero (or a minimum value not more than a predetermined threshold value). To do.

  When the additional supply of the article is possible (that is, when the result of determination in step S7 is “YES”), in step S8, the control device 30 supplies the article to the weighing hopper W that does not store the article. Supply. Then, it returns to step S1.

  On the other hand, if additional supply of articles is not possible (that is, if the result of determination in step S7 is “NO”), then in step S9, control device 30 discharges articles from all weighing hoppers W1 to W10. And treat it as a defective product. For example, by driving the conveyor 20 in the reverse rotation direction (left rotation direction in FIG. 2), the articles on the conveyor 20 are discharged from the combination weighing device 1 to the outside. Thereafter, the process proceeds to step S6.

  If the number of effective heads is not 7 or more in step S4 (that is, if the result of determination in step S4 is “NO”), then in step S10, the control device 30 is stored in the storage unit 31. By referring to the target weight value C0 and the second allowable error value C2, it is determined whether or not the total weight of the articles related to the established combination is equal to or less than the second upper limit value C0 + C2. If there are a plurality of established combinations, the combination with the smallest total weight of the articles is selected.

  When the total weight of the articles related to the established combination is equal to or less than the second upper limit value C0 + C2 (that is, when the determination result in Step S10 is “YES”), the process proceeds to Step S5, and the control device 30 The article is discharged from the weighing hopper W related to the combination and processed as a non-defective product. The operations after step S5 are the same as described above.

  On the other hand, when the total weight of the articles related to the established combination is not less than or equal to the second upper limit value C0 + C2 (that is, when the determination result in step S10 is “NO”), the process proceeds to step S7, and the control device 30 It is determined whether or not additional supply of articles is possible. The operations after step S7 are the same as described above. In the case of passing through step S10, the number of effective heads is less than 7, so the determination result in step S7 is always “YES”. Therefore, step S7 may be omitted and the process may proceed directly from step S10 to step S8.

  In the above description, an example in which the present invention is applied to a linearly arranged combination weighing device has been described. However, the present invention is not limited to this, and the present invention can also be applied to a circular arrangement type combination weighing device in which a pool hopper and a weighing hopper are arranged on the circumference around the dispersion table.

  According to the combination weighing device 1 according to the present embodiment, when the number of effective heads is not 7 or more in step S4 of FIG. 5, the control device 30 determines that the total weight of articles related to the established combination is the second upper limit. It is determined whether or not the value is equal to or less than C0 + C2. When the total weight is equal to or smaller than the second upper limit value C0 + C2, the article is discharged as a good product from the weighing hopper W related to the combination regardless of the total number of the weighing hoppers W storing the article. As described above, even when the number of effective heads is not 7 or more, if the total weight satisfies the condition that the total weight is not more than the second upper limit value C0 + C2, the combination weighing device is discharged by discharging the article as a good product. The operating rate of 1 is improved. In this case, the use of the second upper limit value C0 + C2 that is stricter than the first upper limit value C0 + C1 can prevent the measurement accuracy from being lowered.

  Further, according to the combination weighing device 1 according to the present embodiment, the second allowable error value C2 for defining the second upper limit value C0 + C2 is not the weight value, but the first upper limit value C0 + C1 (strictly, the first upper limit value C0 + C2). It is set as a value of a certain ratio with respect to 1 allowable error value C1). Accordingly, it is not necessary for the operator to re-enter the second upper limit value C0 + C2 (strictly, the second allowable error value C2) every time the first upper limit value C0 + C1 is changed. Since the upper limit value can be automatically updated, the labor of the operator is reduced.

1 is a top view schematically showing an overall configuration of a combination weighing device according to an embodiment of the present invention. 1 is a front view schematically showing an overall configuration of a combination weighing device according to an embodiment of the present invention. It is sectional drawing which shows the cross-section of a combination weighing device. It is a block diagram which shows the structure of the control system of a combination weighing device. It is a flowchart which shows the flow of operation | movement of a combination weighing device.

Explanation of symbols

1 Combination Weighing Device 30 Control Device H (H1 to H10) Head P (P1 to P10) Pool hopper W (W1 to W10) Weighing hopper R (R1 to R10) Load cell

Claims (2)

A plurality of weighing hoppers for temporarily storing articles to be weighed;
Weighing means for weighing the articles stored in each of the weighing hoppers;
Control means for controlling the discharge of articles from each of the weighing hoppers based on the weighing results of the plurality of weighing means,
Regarding the weight value of the article, a target value, a first upper limit value larger than the target value, and a second upper limit value larger than the target value and smaller than the first upper limit value are set,
The control means includes
A first condition that there is a combination of the weighing hoppers that realizes a weight value that is greater than or equal to the target value and less than or equal to the first upper limit value, and that the total number of the weighing hoppers that store articles is greater than or equal to a predetermined number When satisfying, discharge the article from the weighing hopper according to the combination,
When the first condition is not satisfied, there is a combination of the weighing hoppers that realizes a weight value that is greater than or equal to the target value and less than or equal to the second upper limit value, regardless of the total number of the weighing hoppers that store articles. A combination weighing device that discharges articles from the weighing hopper according to the combination when the second condition is satisfied.   The combination weighing device according to claim 1, wherein the second upper limit value is set as a value of a certain ratio with respect to the first upper limit value.

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