JPH0516735B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field of the Present Invention> The present invention is a method for grouping a plurality of articles, such as confectionery, fruits, vegetables, etc., whose individual weights vary so that they have a substantially constant weight. This invention relates to a combination weighing device that is used when filling bags into bags.

<Prior Art> (Figs. 4 and 5) A combination weighing device is generally used to group together a plurality of objects to be weighed whose individual weights vary by a predetermined weight.

In this combination weighing device, the optimal combination is set for each weighing value of the objects to be weighed that are supplied from each feeder to multiple weighing hoppers, and the objects to be weighed in the set weighing hoppers are discharged and put together. However, in order to select combinations efficiently, it is necessary to ensure that the amount of objects to be weighed by each feeder to each weighing hopper always reaches a predetermined weight (i.e., the value obtained by dividing the set weight by the target number of combined hoppers). The values must be very close.

Therefore, even if the parameters for power feeding control are constant, the amount supplied from the feeder varies greatly due to fluctuations in power supply voltage, humidity, temperature, etc.

For this reason, a combination weighing device as shown in FIG. 4 has conventionally been used.

That is, in this combination weighing device, objects to be weighed corresponding to the set weight divided by the target combination hopper number are supplied to the plurality of weighing hoppers 2 ₁ to 2n by the feeders 1 ₁ to 1n, and each weighing hopper is The objects to be weighed in the weighing hoppers are weighed by the weighing devices 3 ₁ to 3n provided for each of the hoppers 2 ₁ to 2n, respectively.

The outputs of the weighing instruments 3 ₁ to 3n are input to the combination selection circuit 4, and the optimum combination is selected from among the combination weights calculated for all different combinations, and the weights in the selected weighing hopper are The objects to be weighed are discharged and collected into a collection chute 5 or the like.

On the other hand, the measured values from each of the measuring instruments 3 ₁ to 3 n are output to the control circuit 6 .

The control circuit 6 controls the feeding forces of all the feeders so that the average amount of feed per weighing hopper 2 ₁ to 2n approaches the target set weight.

By this control, fluctuations in the supply amount due to temperature changes of the feeders 1 ₁ to 1 n are suppressed, and the feeder as a whole supplies the object to be weighed very close to the target weight Wm.

Japanese Patent Laid-Open No. 59-623 discloses a system for controlling the feeding force of the entire feeder in this manner.

This technology subtracts the total weight of the objects to be weighed in the accommodated hoppers from the overall target weight, which is obtained by multiplying the target weight per weighing hopper by the number of all hoppers, and divides the result by the number of empty hoppers. The next feeding force for an empty hopper is controlled by the ratio of the target weight per hopper and the target weight per hopper.

<Problems to be Solved by the Present Invention> However, in the feeder control described above, when the number of empty hoppers doubles, for example,
There was a problem in that the feeding force parameter of the next feeder had to be changed twice, and a feeder with an extremely wide feeding force variable range had to be used.

Furthermore, as shown in Fig. 5, the feeding force parameter of the feeder and the actual supply amount are often not proportional to each other. There was also the problem that the supply amount was unstable due to excessive or insufficient control.

An object of the present invention is to provide a combination weighing device that solves the above problems.

<One Embodiment of the Present Invention> (FIGS. 1 to 3) An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a schematic diagram of the mechanism section of the combination weighing device, and FIG. 2 is a schematic diagram of the control section.

In FIG. 1, reference numeral 11 is a feeder that sequentially supplies objects to be weighed to a circular feeder 12. . N intermediate hoppers 1 are provided below the periphery of the circular feeder 12.
4 ₁ to 14n are arranged in a circular manner, and objects to be weighed are supplied via feeders 13 ₁ to 13n, respectively.
Weighing hoppers 16 ₁ to 16n are set below the intermediate hoppers 14 ₁ to 14n, respectively. The objects to be weighed accommodated in the intermediate hoppers 14 ₁ to 14n are
When the discharge gates 15 ₁ to 15n are opened, the samples are dropped into the weighing hoppers 16 ₁ to 16n, respectively.

Weighing devices 17 ₁ to 17n are arranged in the weighing hoppers 16 ₁ to 16n, respectively. Measuring instrument 17 ₁
~17n are weighing hoppers 16 ₁ ~16n, respectively.
weighs the object to be weighed housed in the weighing machine and outputs the measured value.

A collection chute 19 is installed below the weighing hoppers 16 ₁ to 16n. Weighing hopper 16 ₁
When the discharge gates 18 ₁ -18n of the weighing hoppers 16 1 -16n are opened, the objects to be weighed stored in the weighing hoppers 16 ₁ -16n fall into the collection chute 19.

A packaging machine 21 is installed below the collection chute 19. At the bottom of the collection chute 19, a timing hopper 20 is provided which opens at regular intervals or in synchronization with the packaging machine 21.

The opening and closing of the discharge gates 18 ₁ to 18 n are controlled by the discharge control device 33 of the combined discharge device 30 .

The combination discharge device 30, as shown in FIG.
A measured value storage circuit 31, a combination selection circuit 32,
The discharge control device 33 is also provided.

Each measurement value from the measuring instruments 17 ₁ to 17n is
It is sent to the measured value storage circuit 31 of the combination discharge device 30. The weighing value storage circuit 31 is connected to the weighing hopper 16 ₁ ~
The weighing values of the contents in 16n are stored respectively.

The combination selection circuit 32 includes a combination calculation section 32a that calculates all different combinations based on the weighing values of the contents of the weighing hoppers 16 ₁ to 16n stored in the weighing value storage circuit 31, and a combination calculating section 32a that calculates the set weight W. Weight setting unit 32b that stores settings, combined weight output of combination calculation unit 32a, and weight setting unit 32b
and a set weight output, and selects, for example, the combination of weighing hoppers with the smallest difference from the set weight as the optimal combination, and outputs a combination selection signal.

Upon receiving the combination selection signal, the discharge control device 33 opens a designated one of the discharge gates 18 ₁ to 18n and, after a certain period of time, opens the discharge gate of the intermediate hopper to the weighing hopper that has already been discharged. Open and close as shown.

Further, each measurement value from each of the scales 17 ₁ to 17n is sent to a supply amount control circuit 40 for controlling the amount of feeder supplied to an empty weighing hopper, as shown in FIG.

The supply amount control circuit 40 includes a total weight calculation circuit 41
, an accommodated hopper number detection circuit 42, a divider 46 as an average accommodation amount calculation means, a target weight calculation circuit 47, a parameter candidate value calculation circuit 50, a determination circuit 54, and a feeder drive device 72. ing.

The weighing values from each weighing device 17 ₁ to 17n are input to the total weight calculating circuit 41, and the weighing values from the total weighing hoppers 16 ₁ to 1 are inputted to the total weight calculating circuit 41.
The metric values for 6n are added.

In addition, the measured values from each measuring device 17 ₁ to 17n are as follows:
Comparators 43 ₁ to 4 of the accommodated hopper number detection circuit 42
3n respectively. Comparators 43 ₁ to 43
n compares the value representing zero weight set in the zero setting device 44 with the measured value, and sets "1" if the measured value is greater than zero, and "0" if it is zero.
Output to bit adder 45. Bit adder 45
The outputs of the comparators 43 ₁ to 43n are added. Therefore,
The output L of bit adder 45 represents the number of non-empty accommodated weighing hoppers. The divider 46 converts the added value Wa from the total weight calculation circuit 41 into the bit adder 4.
Divide by the output L of 5. Therefore, the output Wa/L of the divider 46 represents the average amount of objects to be weighed that are being supplied to the weighing hopper.

The divider 48 of the target weight calculation circuit 47 divides the set weight W set in the weight setting section 32b by the target combination hopper number M set in the target combination hopper number setter 49. Therefore, the output W/M of the divider 48 represents the target weight for each weighing hopper when the set weight W is obtained by combining M weighing hoppers.

Divider 51 of parameter candidate value calculation circuit 50
divides the average capacity from divider 46 by the target weight of divider 48. The output of the divider 51 thus represents the ratio of the target weight per weigh hopper to the average capacity per weigh hopper that is not empty at this stage.

The feeding force parameter storage device 52 stores and outputs feeding force parameters for controlling the amount of objects to be weighed from the feeder to the weighing hopper. Multiplier 53
Now, the output of the divider 51 is multiplied by the sending power parameter. Therefore, the output of the multiplier 53 represents a candidate value of the feeding force parameter that will cause the next average capacity to approach the target weight W/M.

Multiplication output of multiplier 53 (parameter candidate value)
is input to the determination circuit 54.

Here, the determination circuit 54 is configured as shown in FIG. This determination circuit 54 includes a subtraction unit 54a that determines the difference between the parameter candidate value and the current feeding power parameter, a determination unit 54b that determines whether the difference is within the range of ±α, and the determination result The parameter updating unit 54c updates the sending power parameters according to the parameters.

In the figure, the parameter candidate value is calculated by the subtraction unit 5.
It is input to subtracters 55 and 56 of 4a. Subtractor 5
5 is the value stored in the sending force parameter storage unit 52,
The parameter candidate value is subtracted, and the subtraction result is output to the subtracter 57 of the determination unit 54b.

The subtracter 57 subtracts the set value α of the tolerance setter 71 from the output of the subtracter 55 and outputs the subtraction result to the comparator 58.

The comparator 58 compares the output value from the subtracter 57 with zero, and when the output value of the subtracter 57 is greater than zero, it outputs an "H" level voltage, and when it is smaller than zero, it outputs an "H" level voltage. Outputs L” level voltage.

Therefore, when the output of the comparator 58 is at the "H" level, the parameter candidate value is smaller than the value stored in the sending power parameter storage 52, and the difference therebetween exceeds the set value α. It shows.

On the other hand, the subtracter 56 calculates, from the parameter candidate value,
By subtracting the value stored in the sending force parameter storage device 52,
This is output to the subtracter 59.

The subtracter 59 subtracts the set value α of the tolerance setter 71 from the output of the subtracter 56 and outputs the subtraction result to the comparator 60.

The comparator 60 compares the output value from the subtracter 59 with zero, and outputs an "H" level voltage when the output value of the subtracter 59 is greater than zero, and outputs an "L" level voltage when it is smaller than zero. ” Outputs level voltage.

Therefore, when the output of the comparator 60 is at the "H" level, it indicates that the parameter candidate value is larger than the value stored in the sending power parameter storage 52, and that the difference exceeds the set value α. .

Further, when the outputs of both comparators 58 and 60 are at "L" level, it indicates that the absolute value of the difference between the parameter candidate value and the value stored in the sending power parameter storage 52 does not exceed the set value α. There is.

The outputs of both the comparators 58 and 60 are input to one input terminal of the AND circuits 61 and 62 of the parameter updating section 54c, and are also input to the inverter 6, respectively.
4 and 65, the level voltage is inverted and inputted to the AND circuit 63.

An “H” level determination pulse P for storing a new sending force parameter in the sending force parameter storage 52 is input to one input terminal of each AND circuit 61 , 62 , 63 .

Each AND circuit 61, 62, 63 turns on one of the switches 66, 67, 68 in synchronization with this determination pulse P, depending on the output level of both comparators 58, 60.

One end side of each switch 66, 67, 68 is connected to the sending force parameter memory 52, and the other end side of the switch 66 is connected to an adder for adding the stored value of the sending force parameter memory 52 and the set value α. 69.

The other end of the switch 67 is a subtracter 7 that subtracts the set value α from the value stored in the sending force parameter memory 52.
0 output.

Further, the other end of the switch 68 is connected to the multiplier 53.
is connected to the multiplication output of

Therefore, the judgment pulse P is applied to each AND circuit 61, 6.
2, 63, if the output of the comparator 58 is "H" level, the switch 67 is turned on,
The subtraction result of the subtracter 70 is stored as a new sending force parameter in the sending force parameter storage 52, and if the output of the comparator 60 is at "H" level, the switch 66 is turned ON and the addition of the adder 69 is performed. The result will be stored in the sending force parameter storage 52 as a new sending force parameter.

Furthermore, if the outputs of both comparators 58 and 60 are both at "L" level, the switch 68 is turned on.
The parameter candidate values are stored as they are in the sending power parameter storage 52.

The stored value of the sending force parameter memory 52 is sent to the multiplier 53 and the feeder driving device 72.

The feeder drive device 72 includes a supply control circuit 73
and multipliers 74 ₁ to 74n and drive circuits 75 ₁ to 75n provided for each feeder 13 ₁ to 13n.
In the supply control circuit 73,
A supply signal (“1” or “0”) for supplying a new object to be weighed to the discharged empty weighing hopper is output. In the multipliers 74 ₁ to 74 n, the supply signal “1” or “0” output from the supply control circuit 73 corresponding to the metering hopper to be supplied and the sending force parameter stored in the sending force parameter storage 52 are used. Multiply by The drive circuits 75 ₁ to 75n drive the feeders 13 ₁ to 13n according to the outputs from the multipliers 74 ₁ to 74n.

<Operation of Embodiment> Next, the operation of the combination weighing device according to the above embodiment will be specifically explained.

The object to be weighed is supplied to the intermediate hoppers 14 1 to 14n by the feeders 13 ₁ to 13n via the supply device 11 and the circular feeder 12, and then to each of the weighing hoppers 16 _{1 to} 16 via the intermediate hoppers 14 ₁ to 14n.
n and weighed.

Therefore, N total weighing hoppers 16 ₁ to 16n
Of these, L weighing hoppers already contain objects to be weighed by each feeder, and the remaining (N-L)
Assuming that the weighing hoppers have been discharged and are empty, the weighing values from the weighing devices 17 ₁ to 17n corresponding to the weighing hoppers 16 ₁ to 16n are input to the comparators 43 ₁ to 43n. It is detected whether it is empty or not, and a signal representing L is outputted from the bit adder 45 to the divider 46.

On the other hand, each weighing value is added in the total weight calculation circuit 41, and the total weight Wa is outputted to the divider 46. The quantity Wa/L is output.

The target weight calculation circuit 47 outputs the target weight W/M per weighing hopper.

The parameter candidate value calculation circuit 50 divides this target weight per weighing hopper by the average capacity of L weighing hoppers that are not empty, multiplies it by the current feeding force parameter _F0 , and calculates the parameter candidate value. seek.

This parameter candidate value _F1 is [(W/M)÷(Wa/L)] _F0 . This parameter candidate value F ₁ is then input to the determination circuit 54 .

In the determination circuit 54, the parameter candidate value F ₁ and
The size relationship with the current feeding force parameter F ₀ and
A determination is made as to whether the absolute value of the difference exceeds the set value α.

In other words, the parameter candidate value F ₁ is larger than the current feeding force parameter F ₀ , and the difference is
If it is larger than the set value α, it is determined that there is a temporary abnormality in one of the feeders and the supply amount is low, and only the set value α is added to the current feeding force parameter F ₀ . The value F ₀ +α is stored in the sending force parameter storage 52 via the switch 66 as a new sending force parameter.

In addition, if the parameter candidate value F ₁ is smaller than the current feeding force parameter F ₀ and the difference is larger than the set value α, it is assumed that a temporary abnormality has occurred in one of the feeders. , it is determined that the supply amount is large, and the value F ₀ −α obtained by subtracting only the set value α from the current feeding force parameter F ₀ is set as the new feeding force parameter via the switch 67. It is stored in the storage device 52.

Furthermore, if the absolute value of the difference between the current feeding force parameter F ₀ and the parameter candidate value F ₁ is smaller than the set value α, the multiplication result F ₁ is set as the new feeding force parameter via the switch 68. It is stored in the sending force parameter storage 52.

The newly stored feeding force parameter is sent to the feeder drive device 72, and the drive circuits 75 ₁ to 75n corresponding to the empty weighing hopper drive the feeder according to this new feeding force parameter, and the empty weighing hopper is driven. The amount of objects to be weighed supplied to the hopper is controlled.

For example, when the total number of weighing hoppers is 16 and the number of empty hoppers is 3, the next feeding force parameter is (16-3) / (16-6) = 13 / 10 In other words, the difference is only 1.3 times, and a feeder with a narrow range of variable feeding force can be used.

Also, when the set value α is set to about 0.3, for example,
The next feeding force parameter can be prevented from changing by more than 0.3 from the current feeding force parameter, and the feeding force can be gently controlled in response to abnormal fluctuations in the supply amount.

When the supply to all the weighing hoppers 16 ₁ to 16n is completed in this way, the combination selection circuit 32 selects a combination based on the measured values stored in the measured value storage circuit 31 for all the weighing hoppers 16 ₁ to 16n. The combination weight is calculated for all different combinations, the combination of weighing hoppers with the smallest difference from the set weight W set in the weight setting section 32b is selected, and a combination selection signal is sent to the discharge control device 33. . The discharge control device 33 opens the discharge gate of the weighing hopper designated by the combination selection signal, and the discharge is discharged into the collection chute 19. The objects to be weighed are grouped together in a collection chute 19, and when a timing hopper 20 is opened, they fall into a packaging machine 21 and are packed into bags.

When one combination discharge is completed in this way, the empty weighing hopper that has already been discharged is filled with objects to be weighed from each feeder whose feeding force is similarly controlled by the supply amount control circuit 40. Then, the combination weighing is repeated in the same manner.

<Effects of the present invention> As described above, the combination weighing device of the present invention has a parameter candidate value calculated from the ratio of the average accommodation amount of objects to be weighed in the accommodated hopper and the target weight per hopper. If the parameter candidate value is within a predetermined range established based on the current feeding power parameter, the parameter candidate value is used as the new feeding power parameter, and if it exceeds that range, the upper or lower limit value of the range is set. It is configured to control the feeding force of the feeder next time as a new feeding force parameter.

Therefore, even if the number of empty hoppers changes, the feeding force parameter does not change significantly, and a feeder with a narrow feeding force variable range can be used.

Furthermore, even if the relationship between the feeding force parameter of the feeder and its supply amount is not proportional, the feeder will not be over-controlled, and moreover, if abnormal supply occurs, gentle control can be performed. .

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram showing the mechanism of a combination weighing device according to an embodiment of the present invention, FIG. 2 is a schematic block diagram of the control section, and FIG. 3 is a block diagram showing the main parts of FIG. 2. It is a diagram. FIG. 4 is a schematic configuration diagram showing a conventional combination metering device, and FIG. 5 is a diagram showing the relationship between the sending force parameter and the supply amount of the conventional combination metering device. 13 ₁ to 13n... feeder, 17 ₁ to 17n...
...Measuring instrument, 30...Combination discharge device, 31...Measurement value storage circuit, 32...Combination selection circuit, 33...
... Emission control device, 40 ... Supply amount control circuit, 41
... Total weight calculation circuit, 42 ... Accommodated hopper number detection circuit, 46 ... Divider, 47 ... Target weight calculation circuit, 50 ... Parameter candidate value calculation circuit, 52
...Transmission force parameter storage device, 54...Judgment circuit,
71...Tolerance setting device, 72...Feeder control device.

Claims (1)

[Scope of Claims] 1. A plurality of weighing hoppers 16 ₁ to 16n, a plurality of weighing instruments 17 ₁ to 17n that respectively weigh objects to be weighed supplied to the plurality of weighing hoppers, and a combination discharging device 30 for selecting an optimal combination of objects to be weighed based on each weighing value and discharging the selected objects to be weighed; A plurality of feeders 13 each supplying objects to be weighed
₁ to 13n, and a feeding force parameter storage 52 that stores common parameters for feeding force control common to each feeder in order to control the feeding force of each of the plurality of feeders.
and an accommodated hopper number detection circuit 42 that receives weighing signals from the plurality of weighing devices and detects the number of accommodated hoppers containing objects to be weighed among the plurality of weighing hoppers; a total weight calculation circuit 41 that calculates the total weight value of the objects to be weighed in the completed hoppers; and an average unit that divides the total weight value by the number of accommodated hoppers to calculate the average accommodation amount per accommodated hopper. capacity calculation means 46; and a value obtained by dividing a predetermined target weight by the average capacity calculated by the average capacity calculation means, and a common value of the feeder at the current stage stored in the feeding force parameter storage device. parameter candidate value calculation means 51, 53 for calculating the result of multiplying the parameters as a candidate value of the common parameter at the next stage; and the candidate value calculated by the parameter candidate value calculation means and the common parameter at the current stage. a subtracting means 54a for calculating the difference between the subtracting means; a determining means 54b for determining whether the subtraction result of the subtracting means is within a preset upper limit value and a lower limit value; When it is determined that the subtraction result is within the range of the upper limit value and the lower limit value, the candidate value is set as a new common parameter, and when it is determined that the subtraction result is larger than the upper limit value,
The value obtained by adding the upper limit value to the common parameter at the current stage is set as a new common parameter, and when the result of the subtraction is determined to be smaller than the lower limit value, the value obtained by subtracting the lower limit value from the common parameter at the current stage is set as a new common parameter. A combinational weighing device comprising a parameter updating means 54c for updating as a common parameter.