JP4676837B2 - Combination scale - Google Patents

Description

  The present invention relates to a combination weigher. More specifically, the present invention relates to a combination weigher that changes combination conditions in accordance with operating conditions.

In combination weighing, there is a combination weighing device disclosed in Patent Document 1 as a method for changing combination conditions in accordance with an operation state. In this combination weighing device, if a combination satisfying the combination condition is obtained, the objects to be weighed are discharged to the packaging machine. On the other hand, when a combination satisfying the combination condition cannot be obtained (in the case of a combination failure), the combination machine is additionally input and the combination calculation is performed again. If a combination failure occurs consecutively a predetermined number of times, the combination conditions, i.e., the upper limit value or upper / lower limit value of the allowable range, are relaxed without stopping the device, and the combination weighing machine that meets this condition is covered. Forcibly discharge the sample. Forcibly discharged objects to be weighed are eliminated as defective products using a weight checker.
Japanese Patent Publication No. 6-63816

  However, in the combination weighing device having the above-described conventional configuration, the entire amount of the objects to be weighed discharged under relaxed conditions is excluded as defective discharge. When handling fresh foods or the like, if the object to be weighed that has been defectively discharged is put into the combination weigher again, the residence time becomes longer, leading to deterioration of the object to be weighed. On the other hand, if the objects to be weighed are discarded, the yield decreases.

  The present invention has been made in order to solve the above-described problems. A combination weigher or a combination weighing method that prevents deterioration of an object to be weighed or a decrease in yield by changing a combination condition according to an operation state. It is intended to provide.

  The present inventors have found that the above-mentioned problems are remarkable in foods such as chicken, octopus, bonito, and squid, and have conducted intensive studies for the purpose of improving the yield during measurement. As a result, the following findings were obtained.

  Ingredients such as chicken, octopus, bonito and squid are not uniform in size and shape, and it is difficult to measure such ingredients with a fully automatic combination scale. In particular, in the part that distributes the objects to be weighed to the weighing unit, it is necessary to smoothly process the unshaped objects to be weighed in units of 1 to 3, so that it is difficult to automate by a machine. In the weighing of the object to be weighed, a semi-automatic combination weigher is used in which only the part for distributing the object to be weighed to the weighing unit is performed by the operator's hand. In the semi-automatic combination weigher, an object to be weighed supplied from upstream is stored in a storage unit, and is distributed to each measurement unit by an operator.

  In a semi-automatic combination weigher, variations in the amount of each metering unit are likely to occur due to the level of skill of the worker and the non-uniformity of the size of the food material itself (hereinafter referred to as a non-homogeneous factor). In combination weighing, if the measurement value (the weight of the object to be weighed held by the weighing unit) varies greatly (for example, if there is a weighing unit with an extremely large holding weight), it is difficult to obtain a combination that satisfies the combination condition. Become. In such a case, in the conventional configuration, forced discharge increases and yield decreases. It can be considered that the yield can be improved by returning the forcibly discharged objects to be stored again. However, if the storage amount of the storage unit increases and the discharge amount to the packaging machine decreases, the residence time becomes longer, the deterioration of the weighing object occurs, the product value decreases, and the yield also decreases.

  If the combination conditions are relaxed, it is considered that forced discharge is less likely to occur and deterioration of the weighing object can be prevented. However, if the combination conditions are relaxed, the combination accuracy decreases. In general, in the packaging of foodstuffs, the weight displayed on the packaging is set as a target weight, and this is used as the lower limit, and the combined total weight is measured so as to exceed the lower limit. If the combination accuracy is lowered, there arises a problem that the yield is lowered by the amount of extra discharge. In order to improve the yield, it is necessary to reduce the relaxation of the combination conditions to the minimum necessary level. However, since the homogenization factors vary in various ways at the measurement site, it has been very difficult to always set the combination conditions appropriately.

  Here, the present inventors have thought that there is a correlation between the combination condition and the storage amount. If the combination conditions are relatively strict with respect to the heterogeneous elements, the discharge rate of the objects to be weighed becomes slow, and the amount of storage increases without catching up with the supply rate from the upstream. If the combination condition is loose with respect to the heterogeneous element, the discharge rate of the object to be weighed becomes high, and the stored amount is reduced by discharging more than the supply rate from the upstream. Generally, the discharge rate of the combination weigher needs to substantially match the supply rate from the upstream. On the other hand, it can be said that setting the discharge speed to coincide with the supply speed from the upstream leads to prevention of deterioration of the object to be weighed and a decrease in yield. If the combination condition is adjusted by feedback control based on the storage amount, the discharge rate can be kept appropriate even if the heterogeneous factors and the supply rate from the upstream fluctuate, deteriorating the weighing object and reducing the yield. Can be prevented.

  On the other hand, there are cases where there is a margin in the discharge capacity for reasons such as a high level of skill of the worker. In such a case, even if a large amount of objects to be weighed is temporarily supplied from the upstream and the storage amount increases, it is not necessary to loosen the combination conditions. This is because if the worker increases the work speed, the discharge speed is improved and the storage amount is naturally reduced. In consideration of such a situation, the combination condition can be relaxed only when it is difficult to obtain a combination that satisfies the combination condition due to an increase in heterogeneous elements (variation), such as a low level of skill of the operator. desirable. If the heterogenization factor expands, a specific weighing unit (for example, a weighing unit with an excessive amount of objects to be weighed) may not substantially participate in the optimal combination (the combination condition will always fall out of the combination condition). is there. In such a case, the number of combination candidates is substantially reduced, and it is often difficult to satisfy the combination conditions. Therefore, the combination condition may be controlled based on both the storage amount and the number of weighing hoppers (residence weighing hoppers) that are waiting without being able to participate in the optimum combination. According to such a method, when the heterogeneous factor is large and the combination condition is difficult to be satisfied, the combination condition can be relaxed, and deterioration of an object to be weighed and a decrease in yield can be prevented. On the other hand, when there is a margin in the discharge capacity, the combination conditions can be maintained strictly, so that the yield is further improved.

  In order to solve the above problems, a combination weigher of the present invention is transferred from a storage unit that stores an object to be measured, a storage amount detection device that detects a storage amount of the object to be measured in the storage unit, and a storage unit. A plurality of weighing units for holding and discharging an object to be weighed, a holding weight detecting device for detecting the weight of an object to be weighed held in each of the weighing units, and a control device, and the control device includes: The combination condition is changed based on the storage amount, and the combination calculation is performed based on the retained weight and the combination condition, and the objects to be weighed are discharged from the weighing units participating in the optimum combination.

  In such a configuration, the combination condition (combination accuracy) can be feedback-controlled according to the storage amount (residence time). Therefore, it is possible to optimize the yield by balancing the dwell time and the combination accuracy. That is, by adjusting the combination conditions, it is possible to prevent deterioration of an object to be measured or a decrease in yield.

  In the combination weigher of the present invention, the storage amount may be a weight of an object to be weighed stored in the storage unit. In such a configuration, it is possible to prevent deterioration of the object to be weighed or a decrease in yield by detecting the weight of the storage unit and performing feedback control of the combination condition based on the weight.

  In the combination weigher of the present invention, the control device may relax the combination condition as the storage amount increases. In such a configuration, as the storage amount increases, the combination condition is relaxed. Therefore, it is possible to balance the dwell time and the combination accuracy, and to prevent deterioration of an object to be measured or a decrease in yield.

  In the combination weigher of the present invention, the control device may relax the combination condition when the storage amount is equal to or greater than a predetermined threshold. In such a configuration, the combination condition is relaxed only when the storage amount is equal to or greater than a predetermined threshold, so that the dwell time and the combination accuracy are balanced to prevent the deterioration of the weighing object or the yield. it can.

  Further, in the combination weigher of the present invention, the control device is a weighing in which the storage amount is equal to or greater than a predetermined threshold value, and the object to be weighed is held without being able to participate in the discharge combination continuously for a predetermined number of times. The combination condition may be relaxed when the number of parts reaches a predetermined number or more. In such a configuration, the combination condition is relaxed only when both the amount of storage and the number of staying weighing units increase. When the supply amount of the objects to be weighed temporarily increases and the storage amount increases, the combination condition is not changed. Therefore, the yield can be further improved.

  In the combination weighing method of the present invention, the objects to be weighed are stored in the storage unit, the objects to be weighed are transferred from the storage unit to the plurality of weighing units, and the objects to be weighed held in each of the weighing units are stored. The weight is detected, the weight of the weighing object stored in the storage part is detected, and the combination condition is relaxed when the weight of the weighing object stored in the storage part exceeds a predetermined threshold. The combination calculation is performed based on the weight held by the weighing unit and the combination condition, and the objects to be weighed are discharged from the measurement unit participating in the combination satisfying the combination condition based on the result of the combination calculation.

  According to this method, it is possible to feedback control the combination condition (combination accuracy) according to the storage amount (retention time). Therefore, it is possible to optimize the yield by balancing the dwell time and the combination accuracy. That is, by adjusting the combination conditions, it is possible to prevent deterioration of an object to be measured or a decrease in yield.

  In the combination weighing method of the present invention, the objects to be weighed are stored in the storage unit, the objects to be weighed are transferred from the storage unit to the plurality of weighing units, and the objects to be weighed held in each of the weighing units are stored. The weight is detected, the weight of the weighing object stored in the storage unit is detected, the weight of the weighing object stored in the storage unit is equal to or greater than a predetermined threshold value, and continuously for a predetermined number of times. When the number of weighing units that are not able to participate in the discharge combination and hold the objects to be weighed becomes a predetermined number or more, the combination conditions are relaxed, and based on the holding weight of the weighing unit and the combination conditions The combination calculation may be performed, and the objects to be weighed may be discharged from the weighing units participating in the combination satisfying the combination condition based on the result of the combination calculation step.

  In such a method, the combination condition is relaxed only when both the storage amount and the number of the staying measuring parts increase. When the supply amount of the objects to be weighed temporarily increases and the storage amount increases, the combination condition is not changed. Therefore, the yield can be further improved.

  The “combination total weight” means the total weight (measurement value) held by the weighing unit taken out based on the combination when one or more weighing units are taken out from a plurality of weighing units. Say.

  Further, the “combination target weight” refers to a weight targeted by the combination weigher.

  In addition, the “optimal combination” refers to a combination that satisfies the combination condition and provides a combined total weight closest to the combination target weight. The objects to be weighed are discharged for the weighing units participating in the optimum combination. On the other hand, the weighing objects that do not participate in the optimal combination remain without being discharged.

  Further, “more than the threshold value” does not necessarily need to be a range including the predetermined threshold value, and may be a range exceeding the threshold value.

  The “discharge speed” refers to the speed at which the combination weigher discharges to a downstream packaging machine or the like, and does not include discharge due to forced discharge.

  The combination weigher or the combination weighing method of the present invention has the above-described configuration, and has the following effects. That is, it is possible to provide a combination weigher or a combination weighing method that prevents deterioration of an object to be weighed or a decrease in yield by changing a combination condition according to an operation state.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
[Device configuration]
FIG. 1 is a top view showing an example of a schematic configuration of the combination weigher according to the first embodiment of the present invention. FIG. 2 is a front view showing an example of a schematic configuration of the combination weigher according to the first embodiment of the present invention. FIG. 3 is a side view showing an example of a schematic configuration of the combination weigher according to the first embodiment of the present invention. FIG. 4 is a block diagram illustrating an example of a schematic configuration of a control system in the combination weigher according to the first embodiment of the present invention. Hereinafter, the combination weigher of the present embodiment will be described separately for hardware and a control system with reference to FIGS. 1 to 4.

  First, the hardware will be described below. As shown in FIG. 1 to FIG. 3, the combination weigher 100 of the present embodiment is roughly composed of a storage container 101 (storage unit) that stores an object to be weighed, a main body 103 that performs combination weighing of an object to be weighed, and an apparatus An input / output device 104 that inputs control parameters and outputs operating conditions, and a transport device 105 that transports an object to be weighed discharged from the main body 103 are provided. The storage container 101 includes a storage weight sensor 111 (storage amount detection device) that detects the weight (storage amount) of an object to be weighed stored in the storage container 101. The main body 103 includes a base 120 having a rectangular bottom and a rectangular side erected on the rear end of the bottom, and a substantially rectangular shape disposed to extend forward at the upper end of the side. The top plate 102 and a weighing hopper 108 (weighing) arranged through the top plate 102 so that a total of 16 rows in front and rear rows are arranged in a row of 8 pieces per row across the central axis in the horizontal direction of the top plate 102. Part) and 16 weighing weight sensors 109 (holding weight detection devices) housed in the top plate 102 and connected to each of the weighing hoppers 108. A control board 110 (control device) is also stored on the side of the base 120. On the top surface of the top plate 102, 16 input ports 106 are opened in two rows corresponding to the respective weighing hoppers 108. The weighing hopper 108 has a gate (not shown) that is driven to open and close by a motor (not shown). The conveying device 105 is supported by the base 120 and is disposed below the weighing hopper 108 so that the arrangement direction of the weighing hoppers 108 and the running direction of the belt are parallel to each other. A forced discharge container 119 is disposed at the end (right end) opposite to the packaging machine side of the transport device 105. The input / output device 104 is disposed on the side of the base 120.

  The objects to be weighed by the combination weigher 100 of the present embodiment are not particularly limited, but are particularly suitable for weighing meat such as broilers, fish and shellfish such as mongoid and bonito. As an example, a stainless steel sink is used for the storage container 101, but it may be a structure that can temporarily store an object to be weighed supplied from a supply machine, and may be a table or the like. The number of the weighing hopper 108 and the weighing weight sensor 109 is not particularly limited as long as it is plural. As the input / output device 104, for example, a liquid crystal touch panel capable of confirming and setting an operation state on the same screen is used. The input / output device is not necessarily configured as an integral unit, and input and output may be performed by separate devices. The conveyor device 105 uses a belt conveyor as an example, but the object to be weighed discharged from the main body 103 is conveyed to a packaging machine (not shown), and the object to be weighed forcibly discharged (described later) from the main body 103 is forcibly discharged into the container 119. Any material can be used as long as it can be conveyed. The conveying device 105 may be an inverted conical chute that collects and discharges objects to be weighed by gravity. For example, a bucket is used for the forced discharge container 119. For example, a load cell is used for the weighing weight sensor 109 and the stored weight sensor 111.

Next, the control system will be described. As shown in FIG. 4, the control system of the combination weigher 100 of the present embodiment includes a control board 110 (control device), an input / output device 104, weighing hoppers 108 1 to ₁₆ , weighing weight sensors 109 1 to ₁₆ , A stored weight sensor 111 and a transport device 105 are provided. The control board 110 includes a control unit 112, a storage unit 113, a weighing hopper gate drive circuit 115, an A / D conversion circuit 116, a transport device drive circuit 117, and an I / O circuit 118. For example, a CPU is used as the control unit 112. For the storage unit 113, for example, an internal memory is used. The control unit 112, the storage unit 113, the input / output device 104, and the I / O circuit 118 are connected so as to communicate with each other. The A / D conversion circuit 116 and the transport device driving circuit 117 are connected to the control unit 112 so that signals from the control unit 112 can be transmitted. The weighing hopper gate driving circuit 115 is connected to the control unit 112 so that a signal from the control unit 112 can be received. The I / O circuit 118 is connected to the packaging machine so as to communicate with each other. The arrow in the figure indicates the direction in which the signal is transmitted.

The outline of the operation of the control board 110 will be described below with reference to FIG. A parameter indicating a combination target weight, an operating speed condition, or the like is input from the input / output device 104 to the control unit 112. The control unit 112 stores the input parameters and the like in the storage unit 113. The stored parameters and the like are read by the control unit 112, output to the input / output device 104 as necessary, and confirmed by the user. The storage unit 113 also stores a program for performing a combination calculation. The stored weight sensor 111 detects the amount stored in the storage container 101 and transmits it to the A / D conversion circuit 116. The weighing weight sensors 109 1 to ₁₆ detect the weights held by the weighing hoppers 108 1 to ₁₆ and transmit them to the A / D conversion circuit 116. Detection signals (analog signals) sent from the stored weight sensor 111 and the weighing weight sensors 109 1 to ₁₆ are converted into digital signals by the A / D conversion circuit 116 and sent to the control unit 112. The control unit 112 processes the received detection signal and the like using a program stored in the storage unit 113. Furthermore, the control unit 112 outputs a control signal to the metering hopper gate drive circuit 115, controls the weighing hopper _{108 1-16.} Further, the control unit 112 outputs a processing result to the input / output device 104 as necessary. The control unit 112 outputs a control signal to the transport device driving circuit 117 to control the transport device 105. The control unit 112 receives a discharge command signal from the packaging machine via the I / O circuit 118 and sends a discharge completion signal to the packaging machine. By the above operation, the control board 110 detects the weight of the object to be weighed stored in the storage container 101 and the weight of the object to be weighed held and discharged by the weighing hoppers 108 1 to ₁₆ while interlocking with the packaging machine. And operate the combination weigher.

In the combination weigher of this embodiment, the number of the control board 110, the control unit 112, and the storage unit 113 is one. However, a plurality of control boards, control units, and storage units may be provided. The control by the control board, the control unit, and the storage unit may be centralized control or distributed control.
[Outline of operation]
An outline of the operation of the combination weigher 100 of the present embodiment having the above-described configuration will be described with reference to FIGS. 1 to 3. In the following description, a case where the object to be weighed is chicken will be described as an example.

  First, chicken cut into small openings is supplied to the storage container 101 from a feeder (not shown) formed by combining a broiler dismantling unit and a transport device. The chicken meat supplied to the storage container 101 is put into the weighing hopper 108 through the inlet 106 by the user (operator) in units of one to three. The gate of the weighing hopper 108 is normally closed, and the introduced chicken is held in the weighing hopper 108. The control board 110 detects the weight of the chicken (hereinafter referred to as a measured value) held in the weighing hopper 108 via the weighing weight sensor 109. The control board 110 performs a combination calculation using the obtained measurement value. In the combination calculation, an optimum combination that satisfies the combination condition and has the combined total weight (the total of measured values of the weighing hoppers participating in the combination) closest to the combined target weight (target weight for one discharge) is selected. When the selection is completed, the control board 110 opens the gate of the weighing hopper 108 that participates in the optimum combination and supplies the chicken to the transfer device 105. The control board 110 drives the transport device 105 in the forward direction to discharge (appropriate discharge) the supplied chicken meat to a packaging machine (not shown).

  When the discharge to the packaging machine is completed, the chicken is put into the weighing hopper 108 again, and the combination calculation and discharge are performed. The pouring of chicken into the weighing hopper 108 and the supply of chicken into the storage container 101 from the feeder are continuously performed. With this operation, the combination weigher 100 discharges the target amount of chicken to the packaging machine.

When the combination satisfying the combination condition is not obtained in the combination calculation, the control board 110 forcibly discharges the chicken from the weighing hopper 108 having the largest retained weight (the highest measured value). When forced discharge occurs, the control board 110 drives the transfer device 105 in the reverse direction to discharge the chicken into the forced discharge container 119. Thereafter, chicken is again supplied to the weighing hopper 108, and the combination calculation and discharge are performed again. The object to be weighed discharged to the forced discharge container 119 is returned to the storage container 101 by the operator. Or the automatic transfer apparatus which transfers a to-be-measured item from the forced discharge container 119 to the storage container 101 may be installed. It is not necessary to return all the objects to be weighed forcibly to the storage container 101, and a configuration in which a part of the objects is returned may be used.
[Characteristic behavior]
The feature of the combination weigher of the present embodiment is that the combination condition is changed based on the storage amount of the objects to be weighed in the storage container 101. In the following description, the combination total weight (S) is included in a range in which the combination target weight (m) is the lower limit (Mmin) and the combination target weight plus the allowable weight (Δm) is the upper limit (Mmax). In addition, it is assumed that the combination condition is satisfied. The fluctuation of the combination condition in the present embodiment means that the combination condition is relaxed when the storage amount is increased, and that the combination condition is relaxed means that the upper limit Mmax is increased. If the upper limit is increased, forced discharge is less likely to occur, and the discharge rate of the objects to be weighed from the combination weigher to the packaging machine is improved. FIG. 5 is a flowchart showing an example of the operation program of the control board according to the first embodiment of the present invention. Hereinafter, with reference to FIG. 5, an operation that is a feature of the combination weigher of this embodiment will be described.

  When the operation of the combination weigher starts, first, operation parameters are read in step S1. The operation parameters are the threshold value for the number of weighing hoppers for starting the combination (first threshold value), the threshold value for relaxing the combination condition (second threshold value), the combination target weight (m), the normal combination upper limit value (M), and the relaxation value. The amount (α) and the like are stored in the storage unit 113. The operation parameters may be stored in the storage unit 113 in advance, but may be configured to accept input / change of operation parameters by the user via the input / output device 104. The operation parameter may be configured to be changeable during the operation of the combination weigher.

  Next, in step S2, the number (N) of weighing hoppers in which the objects to be weighed are loaded are detected based on the detection result of the weighing weight sensor 109 and the like.

  Next, in step S3, it is determined whether N is equal to or greater than a first threshold value (for example, 6). The first threshold is the number of metric values necessary to maintain combination accuracy. If it is determined that N is not equal to or greater than the first threshold, the process returns to step S2. If it is determined that N is equal to or greater than the first threshold, the process proceeds to step S4.

  In step S4, it is determined whether or not the discharge command signal from the packaging machine is ON. If it is determined that the discharge command signal from the packaging machine is not ON, the process returns to step S4 again and waits until the discharge command signal from the packaging machine is turned ON. If it is determined that the discharge command signal from the packaging machine is ON, the process proceeds to step S5.

  In step S <b> 5, the weight (reserved amount: Mstag) of the weighing object stored in the storage container 101 is detected via the stored weight sensor 111.

  Next, in step S6, it is determined whether or not the storage amount is equal to or greater than a second threshold value (for example, 50 kg). If it is determined that the storage amount is not equal to or greater than the second threshold, the process proceeds to step S7. If it is determined that the storage amount is equal to or greater than the second threshold, the process proceeds to step S8.

  In step S7, normal combination conditions are set. The combination target weight (m: eg 2000 g) is used as the lower limit value (Mmin), and the upper limit value (Mmax) is a normal upper limit value (M: eg 2020 g) obtained by adding the allowable weight (Δm: eg 20 g) to the combination target weight. Is set. When step S7 ends, the process proceeds to step S9.

  On the other hand, in step S8, a relaxed combination condition is set. The combination target weight (m) is the lower limit value (Mmin), and the upper limit value (Mmax) is the relaxation upper limit value obtained by adding the allowable weight (Δm: eg 20 g) and the relaxation amount (α: eg 20 g) to the combination target weight. (M + α: 2040 g, for example) is set. When step S8 ends, the process proceeds to step S9.

  In step S9, a combination operation is performed. There is a combination (a combination satisfying the combination condition) in which the weight (measured value) of the object to be weighed held by each weighing hopper 108 is detected, and the combined total weight falls within the range of the combination condition (the range between Mmin and Mmax). A determination is made whether or not. If it is determined that there is a combination that satisfies the combination condition, the process proceeds to step S10. If it is determined that there is no combination that satisfies the combination condition, the process proceeds to step S11.

  In step S10, the objects to be weighed are discharged from the weighing hoppers participating in the combination having the smallest combined total weight among the combinations that satisfy the combination condition (optimal combination). Then, the transport device 105 is driven in the forward direction, and the objects to be weighed discharged from the weighing hopper are transported by the transport device and discharged to the packaging machine. Then, a discharge completion signal is sent from the control board 110 to the packaging machine. When step S10 ends, the process returns to step S2 and a new weighing cycle is started.

  On the other hand, in step S11, the object to be weighed is forcibly discharged from the weighing hopper that satisfies the forcible discharge condition. Various conditions can be set as the forced discharge condition. The weighing hopper having the largest retained weight (having the highest measured value) may satisfy the forced discharge condition. Two or three weighing hoppers in order of decreasing holding weight may satisfy the forced discharge condition. Alternatively, a weighing hopper whose holding weight exceeds a certain ratio (for example, half) of the combination target weight may be set to satisfy the forced discharge condition. After the forced discharge, the transport device 105 is driven in the reverse direction, and the forcibly discharged object to be weighed is transported by the transport device and discharged to the forced discharge container 119. When step S11 ends, the process returns to step S2 and a new weighing cycle is started.

The above-described operation program is characterized by steps S6 to S8. In this portion, the control board 110 changes the combination condition based on the storage amount of the objects to be weighed in the storage container 101. That is, if the storage amount is not equal to or greater than the predetermined threshold (second threshold), the normal combination condition is set. On the other hand, if the storage amount is equal to or greater than the predetermined threshold, the normal combination condition is set. Also, the relaxed condition (the upper limit value is set higher than usual) is set as the combination condition.
[effect]
If the heterogeneity factor is large, such as a low level of worker skill, large variations in the size and weight of the objects to be weighed, it will be difficult to obtain a combination that satisfies the combination conditions, the discharge speed will be reduced, and the storage volume will be reduced. To increase. According to the above-described configuration and method, the storage amount is detected by the storage weight sensor 111, and when the detected storage amount is high (greater than or equal to the second threshold), the control board 110 relaxes the combination condition. Let If the combination conditions are relaxed, forced discharge is less likely to occur and proper discharge is likely to occur. If the appropriate amount of discharge per hour increases, the discharge rate will improve. If the discharge speed is improved, the residence time is shortened, and deterioration of an object to be weighed and a decrease in yield are prevented.

If the non-homogenization factor is small, such as a high level of skill of the worker and small variations in the size and weight of the objects to be weighed, the amount of storage decreases. According to the above-described configuration and method, when the storage amount is low (smaller than the second threshold value), the combination condition is tightened. By tightening the conditions, the amount that is excessively discharged and packaged over the combined target weight is reduced, and the yield is improved.
[Modification]
The storage amount does not necessarily need to be a weight, and may be a physical quantity having a correlation with the storage amount. For example, it may be the volume of the object to be weighed or the height (level) of the object to be weighed in the container. The storage amount detection device is not necessarily a weight sensor, and may be a sensor capable of detecting a physical quantity having a correlation with the storage amount. For example, a level sensor using an optical sensor may be used.

  Any combination condition may be used. For example, the lower limit value and the upper limit value may be set with a predetermined width with respect to the combination target weight. The variation of the combination condition is not necessarily limited to the relaxation of the combination condition. For example, the combination condition may be tightened when the storage amount decreases. The combination conditions may be relaxed by any method. For example, the combination conditions may be relaxed by further lowering the lower limit value. The combination condition may be continuously changed based on the storage amount. For example, the combination condition may be changed so that the combination condition is continuously relaxed as the storage amount increases.

  The weighing hopper may include two storage units that can hold and discharge the objects to be weighed independently. In this case, it is preferable to provide a supply hopper capable of selectively supplying the objects to be weighed to the storage units upstream of the weighing hopper. The weight of the object to be weighed held by each storage unit can be detected as an increase in the weight of the weighing hopper before and after the loading. Each storage unit functions as a weighing hopper. In such a configuration, since the weight retained in the pair of storage units is detected by one weight sensor, the number of weight sensors can be relatively reduced, and the apparatus can be reduced in size and cost.

  In the present embodiment, the combination condition is set for each combination calculation, but the combination condition may be changed only when a predetermined condition is satisfied. For example, an initial setting value may be set as the combination condition, and the program may be configured to relax the combination condition only when the storage amount increases.

The forced discharge container does not necessarily have to be provided on the opposite side of the packaging machine, and a sorting device (gate) is provided downstream of the transport device. At the time of discharge, the object to be weighed may be discharged into the forced discharge container. With this configuration, there is no need to switch the driving direction of the transport device. Instead of forced discharge, intervention work such as replacement of objects to be weighed by an operator may be performed.
(Second Embodiment)
In the first embodiment, the combination condition is relaxed when the storage amount is equal to or greater than a predetermined threshold. On the other hand, in the second embodiment, a storage hopper (hereinafter referred to as a staying hopper) that holds an object to be weighed without being able to participate in the discharge combination continuously for a predetermined number of times or more when the storage amount is a predetermined threshold or more. This is different from the first embodiment in that the combination condition is relaxed when the number of weighing hoppers) exceeds a predetermined number. Since the configuration and operation of the combination weigher in the second embodiment are the same as those in the first embodiment, the corresponding elements are denoted by the same names and reference numerals, and the description thereof is omitted.
[Characteristic behavior]
The feature of the combination weigher of the present embodiment is that the combination condition is changed based on the storage amount of the objects to be weighed in the storage container 101 and the number of staying weighing hoppers. The fluctuation of the combination condition in the present embodiment means that the combination condition is relaxed when the storage amount is increased, and that the combination condition is relaxed means that the upper limit Mmax is increased. In the following description, the combination total weight (S) is included in a range in which the combination target weight (m) is the lower limit (Mmin) and the combination target weight plus the allowable weight (Δm) is the upper limit (Mmax). In addition, it is assumed that the combination condition is satisfied. If the upper limit is increased, forced discharge is less likely to occur, and the object to be weighed is discharged more smoothly from the combination weigher to the packaging machine. FIG. 6 is a flowchart showing an example of an operation program for the control board according to the second embodiment of the present invention. Hereinafter, with reference to FIG. 6, an operation that is a feature of the combination weigher of this embodiment will be described.

  When the operation of the combination weigher starts, first, operation parameters are read in step S21. The operation parameters include a threshold value for the number of weighing hoppers (first threshold value), a threshold value for the storage amount (second threshold value), a threshold value for the number of waiting times (third threshold value), and a threshold value for the number of staying weighing hoppers (first value). 4), a combination target weight (m), a normal combination upper limit value (M), a relaxation amount (α), and the like, which are stored in the storage unit 113. The operation parameters may be stored in the storage unit 113 in advance, but may be configured to accept input / change of operation parameters by the user via the input / output device 104. The operation parameter may be configured to be changeable during the operation of the combination weigher.

  Next, in step S22, the number (N) of weighing hoppers in which the objects to be weighed are inserted are detected based on the detection result of the weighing weight sensor 109 and the like.

  Next, in step S23, it is determined whether N is equal to or greater than a first threshold value (for example, 6). The first threshold is the number of metric values necessary to maintain combination accuracy. If it is determined that N is not equal to or greater than the first threshold, the process returns to step S22. If it is determined that N is equal to or greater than the first threshold, the process proceeds to step S24.

  In step S24, it is determined whether or not the discharge command signal from the packaging machine is ON. If it is determined that the discharge command signal from the packaging machine is not ON, the process returns to step S24 again and waits until the discharge command signal from the packaging machine is turned ON. If it is determined that the discharge command signal from the packaging machine is ON, the process proceeds to step S25.

  In step S <b> 25, the weight (reserved amount: Mstag) of the weighing object stored in the storage container 101 is detected via the stored weight sensor 111.

  Next, in step S26, it is determined whether or not the storage amount is equal to or greater than a second threshold value (for example, 50 kg). If it is determined that the storage amount is not equal to or greater than the second threshold, the process proceeds to step S27. If it is determined that the storage amount is greater than or equal to the second threshold, the process proceeds to step S28.

  In step S27, normal combination conditions are set. The combination target weight (m: eg 2000 g) is used as the lower limit value (Mmin), and the upper limit value (Mmax) is a normal upper limit value (M: eg 2020 g) obtained by adding the allowable weight (Δm: eg 20 g) to the combination target weight. Is set. When step S27 ends, the process proceeds to step S31.

  On the other hand, in step S28, the number of weighing hoppers in which the number of standby times is equal to or greater than a third threshold (for example, 10 times) is detected and stored as the number of staying weighing hoppers (NS).

  In step S29, it is determined whether the number (NS) of staying weighing hoppers is equal to or greater than a fourth threshold value (for example, 3). If it is determined that the number of staying weighing hoppers is equal to or greater than the fourth threshold value, the process proceeds to step S30. If it is determined that the number of staying weighing hoppers is not equal to or greater than the fourth threshold value, the process proceeds to step S27.

  In step S30, a relaxed combination condition is set. The combination target weight (m) is the lower limit value (Mmin), and the upper limit value (Mmax) is the relaxation upper limit value obtained by adding the allowable weight (Δm: eg 20 g) and the relaxation amount (α: eg 20 g) to the combination target weight. (M + α: 2040 g, for example) is substituted. When step S30 ends, the process proceeds to step S31.

  In step S31, a combination calculation is performed. There is a combination (a combination satisfying the combination condition) in which the weight (measured value) of the object to be weighed held by each weighing hopper 108 is detected, and the combined total weight falls within the range of the combination condition (the range between Mmin and Mmax). A determination is made whether or not. If it is determined that there is a combination that satisfies the combination condition, the process proceeds to step S32. If it is determined that there is no combination that satisfies the combination condition, the process proceeds to step S35.

  In step S32, the objects to be weighed are discharged from the weighing hoppers participating in the combination having the smallest combined total weight (the optimum combination) among the combinations that satisfy the combination conditions. Then, the transport device 105 is driven in the forward direction, and the objects to be weighed discharged from the weighing hopper are transported by the transport device and discharged to the packaging machine. Then, a discharge completion signal is sent from the control board 110 to the packaging machine.

  Next, in step S33, the number of standby times of the weighing hopper from which the object to be weighed is discharged is set to zero (reset). As a result, in the next weighing cycle, the weighing hopper from which the objects to be weighed are discharged is not detected as the staying weighing hopper.

  Next, in step S34, 1 is added to the number of standby times of the weighing hopper that has not discharged the object to be weighed. As a result, in the next weighing cycle, the number of waiting times of the weighing hopper from which the object to be weighed is increased by 1, and if the number of waiting times exceeds the third threshold, it is detected as a staying weighing hopper. Will be. When step S34 ends, the process returns to step S22, and a new weighing cycle is started.

  On the other hand, in step S35, the object to be weighed is forcibly discharged from the weighing hopper that satisfies the forcible discharge condition. Various conditions can be set as the forced discharge condition. The weighing hopper having the largest retained weight (having the highest measured value) may satisfy the forced discharge condition. Two or three weighing hoppers in order of decreasing holding weight may satisfy the forced discharge condition. Alternatively, a weighing hopper whose holding weight exceeds a certain ratio (for example, half) of the combination target weight may be set to satisfy the forced discharge condition. After the forced discharge, the transport device 105 is driven in the reverse direction, and the forcibly discharged object to be weighed is transported by the transport device and discharged to the forced discharge container 119. When step S35 ends, the process proceeds to step S33.

The above-described operation program is characterized by steps S26 to S30. In such a portion, the control board 110 changes the combination condition based on the storage amount of the objects to be weighed in the storage container 101 and the number of staying weighing hoppers. That is, if the storage amount is equal to or greater than a predetermined threshold (second threshold) and the number of staying weighing hoppers is not equal to or greater than the predetermined threshold (fourth threshold), a normal combination condition is set. On the other hand, if the storage amount and the number of staying weighing hoppers each satisfy predetermined conditions, a condition that is more relaxed than the normal combination condition (the upper limit value is set higher than normal) is set as the combination condition.
[effect]
When the heterogeneous element is enlarged, a weighing hopper in which an object to be weighed excessively is generated, and it becomes impossible to participate in the optimum combination. In such a case, there are many cases where the combination candidates are substantially reduced and it is difficult to satisfy the combination conditions. In this embodiment, the weighing hopper that cannot participate in the optimum combination is detected as a staying weighing hopper, and the combination condition is changed based on the storage amount and the number of staying weighing hoppers. That is, the combination condition is relaxed only when the storage amount is high (greater than or equal to the second threshold value) and the number of staying weighing hoppers is large (greater than or equal to the fourth threshold value).

According to such a configuration and method, when the discharge rate is insufficient due to the high heterogeneity factor, rather than a temporary increase in the supply amount, the combination conditions are relaxed to improve the discharge rate, Deterioration of the weighing object and decrease in yield are prevented. On the other hand, if there is a surplus in the discharge capacity due to reasons such as the high level of skill of the worker, and the storage volume has increased due to a temporary supply of a large amount of objects from the upstream, the combination condition is Maintained without being loosened. By preventing unnecessary relaxation of conditions, the amount that is excessively discharged and packaged over the combined target weight is reduced, and the yield is further improved.
[Modification]
Also in this embodiment, the same modification as the first embodiment is possible.

  The combination weigher or the combination weighing method of the present invention is useful as a combination weigher or a combination weighing method for preventing deterioration of an object to be weighed or a decrease in yield by changing a combination condition according to an operation state.

It is a top view which shows an example of schematic structure of the combination weigher of 1st Embodiment of this invention. It is a front view which shows an example of schematic structure of the combination weigher of 1st Embodiment of this invention. It is a side view which shows an example of schematic structure of the combination weigher of 1st Embodiment of this invention. It is a block diagram which shows an example of schematic structure of the control system in the combination weigher of 1st Embodiment of this invention. It is a flowchart which shows an example of the operation program of the control board of 1st Embodiment of this invention. It is a flowchart which shows an example of the operation program of the control board of 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Combination weigher 101 Storage container 102 Top plate 103 Main body 104 Input / output device 105 Conveyance device 106 Input port 108 Weighing hopper 109 Weighing weight sensor 110 Control board 111 Storage weight sensor 112 Control part 113 Storage part 115 Weighing hopper gate drive circuit 116 A / D Conversion circuit 117 Conveying device drive circuit 118 I / O circuit 119 Forced discharge container 120 Base

Claims (7)

A storage section for storing an object to be weighed;
A storage amount detection device for detecting a storage amount of an object to be weighed in the storage unit;
A plurality of weighing units for holding and discharging the objects to be weighed transferred from the storage unit;
A holding weight detection device for detecting the weight of an object to be weighed held in each of the weighing units;
A control device,
The control device changes a combination condition based on the stored amount, and performs a combination calculation based on the retained weight and the combination condition, and discharges an object to be weighed from a weighing unit participating in the optimum combination. .   The combination balance according to claim 1, wherein the storage amount is a weight of an object to be weighed stored in the storage unit.   The combination balance according to claim 1, wherein the control device relaxes the combination condition as the storage amount increases.   The combination weigher according to claim 1, wherein the control device relaxes the combination condition when the storage amount becomes equal to or greater than a predetermined threshold.   In the control device, the storage amount is equal to or greater than a predetermined threshold value, and the number of weighing units that are not able to participate in the discharge combination continuously for a predetermined number of times or more and hold an object to be weighed is equal to or greater than the predetermined number. The combination weigher according to claim 1, wherein the combination condition is relaxed. Store the object to be weighed in the storage part,
Transferring an object to be weighed from the storage unit to a plurality of weighing units;
Detecting the weight of an object to be weighed held in each of the weighing units;
Detecting the weight of the object to be weighed stored in the storage part,
When the weight of the object to be weighed stored in the storage part becomes equal to or greater than a predetermined threshold, the combination condition is relaxed,
Perform combination calculation based on the weight held by the weighing unit and the combination conditions,
A combination weighing method for discharging an object to be weighed from a weighing unit participating in a combination that satisfies a combination condition based on a result of the combination calculation. Store the object to be weighed in the storage part,
Transferring an object to be weighed from the storage unit to a plurality of weighing units;
Detecting the weight of an object to be weighed held in each of the weighing units;
Detecting the weight of the object to be weighed stored in the storage part,
The weight of the weighing object stored in the storage unit is equal to or greater than a predetermined threshold, and the number of weighing units that hold the weighing object without being able to participate in the discharge combination continuously for a predetermined number of times or more. When the number exceeds the specified number, the combination conditions are relaxed.
Perform combination calculation based on the weight held by the weighing unit and the combination conditions,
A combination weighing method for discharging an object to be weighed from a weighing unit participating in a combination that satisfies a combination condition based on a result of the combination calculation step.

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