JPH0251131B2 - - Google Patents

Description

Detailed Description of the Invention <Industrial Application Field of the Present Invention> The present invention is capable of handling articles such as confectionery, fruits, vegetables, etc., which have individual weight variations (hereinafter referred to as lumps), at a substantially constant weight. This invention relates to a combination weighing device that is used when packing a plurality of items into bags according to their weight.

<Prior art> Even if you try to combine multiple pieces of lumps whose individual weights vary by a set weight,
An error occurs between the set weight and the set weight. This error becomes more significant as the average weight of a single lump (hereinafter referred to as an object to be weighed, since it may be a powder instead of a lump).

To solve this problem, a combination weighing device as shown in FIG. 1 has conventionally been used.

That is, in this combination weighing device, approximately M of the set combination weight is applied to the plurality of combination hoppers 2 ₁ to 2n.
A plurality of objects to be weighed corresponding to one part of the weight are fed by feeders 1 ₁ to 1n, and the objects to be weighed accommodated are fed by weighing devices 3 ₁ to 3n provided for each combination hopper 2 ₁ to 2n. Weigh each item. Then, based on the outputs of the scales 3 ₁ to 3n, the combined weight of the object to be weighed by a predetermined number M of combination hoppers is calculated for all different combinations. Among these combination weights, determine the combination with the smallest difference from the set combination weight W,
The objects to be weighed in the M combination hoppers of this combination are discharged and collected in the collection chute 4 or the like.

However, in conventional combination weighing devices with such a configuration, in order to always obtain a combination weight with a small difference from the set combination weight, it is necessary to increase the number of scales, combination hoppers, etc., and increase the number of combinations. You have to make it happen.

However, since measuring instruments are expensive,
If the number is large, the entire device becomes extremely expensive,
In addition, since the measuring device always needs to be adjusted, maintenance is complicated and the reliability of measurement is deteriorated.

In this way, without increasing the number of weighing instruments, combination hoppers, etc., a good combination with a small difference from the set combination weight can always be obtained.
No. 63152 proposes automatic adjustment of the amount of objects to be weighed into a combination hopper.

That is, in the combination weighing device disclosed in Japanese Patent Application No. 56-63152, the sum of each weighing signal is calculated when all weighing hoppers contain objects to be weighed. Then, the target total weight to be loaded into all weighing hoppers is calculated by multiplying the target weight of each object to be weighed to be loaded into each weighing hopper by the number of all weighing hoppers. Then, this target total weight is compared with the sum of the weighing signals, and based on the comparison result,
Adjust the input weight when adding a new object to be weighed.

<Problems to be solved by the present invention> However, in the combination weighing device of Japanese Patent Application No. 57-175923, (a) the total weight when all weighing hoppers are filled with objects to be weighed is the target total weight; By comparison, the next input amount is controlled. Therefore, it is necessary to wait until all weighing hoppers are filled with objects to be weighed.
Since a new input amount cannot be determined, highly efficient combination metering is impossible.

(b) In each combination selection, the combination is selected after all weighing hoppers are filled with objects to be weighed, making highly efficient combination weighing impossible.

(c) Since the input amount is controlled by the filling amount of all weighing hoppers, if, for example, the discharge gate of one or more weighing hoppers breaks down and becomes unusable, a new corresponding one is immediately installed. It is not possible to control the input amount.

There were other problems.

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

<Means for solving the above problem> In the combination weighing device of the present invention for solving the above problem, the set combination weight value set in advance in the combination weight setting section is divided by the preset number of combinations. The target weight per hopper is calculated, and the target weight per hopper is calculated.
An all-hopper target total weight calculation circuit 47 that calculates the target total weight of all hoppers by multiplying the target weight per piece by the total number of all hoppers in movement, and a weight signal for all the hoppers including empty hoppers at the present time. a current total weight calculation circuit 41 that calculates the current total weight by adding the total weight; and an empty hopper that detects the number of empty hoppers by comparing each weight signal for all the hoppers with a value set in a zero setting device. Hopper number detection circuit 42
The total weight output from the current total weight calculation circuit 41 is subtracted from the target total weight of all hoppers output from the target total weight calculation circuit 47, and the difference between the two is calculated. an empty hopper supply amount calculation circuit 52 that calculates the supply amount that should be accommodated per empty hopper by dividing it by the number of empty hoppers output from the empty hopper number detection circuit 42 and outputs a supply amount signal; Based on the supply amount output signal calculated by the empty hopper supply amount calculation circuit 52, the amount of objects to be weighed by the corresponding feeders to each of the empty hoppers is adjusted to approach the calculated supply amount. The feeder control device 55 is characterized in that it is equipped with a feeder control device 55 that controls the feeder.

<Function> As described above, in the combination weighing device of the present invention, the total weight of the hoppers that are only filled at the present time is calculated as the total weight of the hoppers that are only filled at the present time when all the hoppers are not filled and there are empty hoppers. circuit 41
It is calculated by This current total weight is then subtracted from the target total weight of all hoppers. This result becomes the target total weight to be fed into the currently empty hopper. This is calculated by the empty hopper supply amount calculation circuit 5.
2 is divided by the number of empty hoppers. This result becomes the target weight per empty hopper. The feeder control device 55 controls the amount of input into the empty hopper so as to approach this amount.

Therefore, without waiting for all hoppers to be filled, the input control amount is determined while there are empty hoppers.
Therefore, combinations can be selected while empty hoppers are still available. Furthermore, even if one or more hoppers break down, this failure can be handled because the input control amount is not determined based on the full state of all hoppers.

<Embodiments of the present invention> Hereinafter, embodiments of the present invention will be described with reference to the drawings.

3 and 4 show an embodiment of the present invention, FIG. 3 is a schematic diagram of the mechanical section of the combination weighing device, and FIG. 4 is a schematic diagram of the control section.

In FIG. 3, reference numeral 11 is a feeder that sequentially supplies objects to be weighed to a circular feeder 12. N intermediate hoppers 1 are installed below the periphery of the circular feeder 12.
4 ₁ to 14n are arranged in a circular manner, and a plurality of objects to be weighed are supplied via feeders 13 ₁ to 13n, respectively. Below the intermediate hoppers 14 ₁ to 14n,
Measuring hoppers 16 ₁ to 16n are installed respectively. When the discharge gates 15 ₁ -15n are opened, the objects to be weighed accommodated in the intermediate hoppers 14 ₁ -14n fall and are accommodated in the weighing hoppers 16 ₁ -16n, respectively.

Weighing devices 17 ₁ to 17n are installed in the weighing hoppers 16 ₁ to 16n, respectively. Measuring instrument 1
7 ₁ to 17n are weighing hoppers 16 ₁ to 1, respectively.
6n, and outputs a weight signal representing the weight.

A collection chute 19 is arranged below the weighing hoppers 16 ₁ to 16n. Measuring hopper 1
The objects to be weighed stored in the weighing hoppers 16 ₁ to 16n are discharged from the discharge gates 18 ₁ to ₁₈ of the weighing hoppers 16 1 to 16n, respectively.
When 18n is opened, it falls into the collection chute 19.

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

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.
It includes a measured value storage circuit 31, a combination selection circuit 32, and an emission control device 33.

The weight signals from the scales 17 ₁ to 17n are
It is sent to the measured value storage circuit 31 of the combination discharge device 30. The weighing value storage circuit 31 is the weighing hopper 16 ₁
The weight of each stored item within ~16n is memorized.

The combination selection circuit 32 calculates the combined weight of objects to be weighed by combining a predetermined number M of weighing hoppers based on the weight signals of the objects stored in each of the weighing hoppers 16 ₁ to 16n stored in the weighing value storage circuit 31. , a combination calculation unit 32a that calculates all different combinations, a weight setting unit 32b that stores the set weight W, and compares the combination weight output of the combination calculation unit 32a with the set weight output of the weight setting unit 32b, and sets the weight W. It includes a combination determining section 32c that determines the combination of weighing hoppers that has the smallest difference in weight and outputs a combination selection signal.

Upon receiving the combination sorting 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. Opening/closing control is performed as follows.

Further, each weight signal from each weighing device 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 current total weight calculation circuit 41, an empty hopper number detection circuit 42, an all hopper target total weight calculation circuit 47, an empty hopper supply amount calculation circuit 52, and a feeder control device 55. There is.

The supply amount control circuit 40 composed of these components is configured to operate on the following principle.

In other words, the more the weight of the objects to be weighed accommodated in each combination hopper varies from the target weight per piece W/M, which is the set weight W divided by the predetermined number M of combinations, the more the objects to be weighed in the M combination hoppers are The combined combined weight will also vary widely. In other words, as shown by the symbol a in FIG. 2, if the range of variation in the measured values of the objects to be weighed in one combination hopper is wide centered around W/M, the combination of M combination hoppers The width of the weight variation also becomes wider as shown by the symbol b in FIG. Therefore, in order for the combined weight to always be obtained as a value extremely close to the set weight W, the amount of objects to be weighed by each feeder to each combination hopper must always be W/M.
The value must be very close to . This means that the sum of the weights of all combinations of hoppers when objects to be weighed are accommodated is the value (target total weight) obtained by multiplying the target weight per piece W/M by the number N of all combinations of hoppers. This means that combination weights with extremely small differences in set weights can always be obtained.

Therefore, when feeding objects to be weighed to each combination hopper by each feeder, add the weight of the contents of the combination hoppers that have already been fed, and calculate the total amount of material to be fed to the remaining empty combination hoppers. If the total weight of the items stored in the combination hopper is controlled to approximate the target total weight, a combination weight that always has an extremely small difference from the set weight can be obtained. Controlling the feed rate to the remaining empty combination hoppers in this way is much easier by controlling the feed rates to all combination hoppers so that they all become W/M.

That is, the weight signals from each of the weighing devices 17 ₁ to 17n are input to the current total weight calculation circuit 41, and the weight signals from the weighing devices 17 1 to 17n are inputted to the current total weight calculation circuit 41, and the weight signals are inputted to the current total weight calculation circuit 41, and all weighing hoppers 16 ₁ to
The weight signals for 16n are summed.

Moreover, the weight signals from each weighing device 17 ₁ to 17n are sent to the comparators 43 ₁ to 43 of the empty hopper number detection circuit 42.
43n respectively. Comparators 43 ₁ to 43
n is set by comparing the weight signal with the signal representing zero weight set in the zero setting device 44, and is set to "1" if the weight according to the weight signal is larger than zero because it is filled, and "1" if it is empty. If it is zero, "0" is output to the bit adder 45.

Bit adder 45 adds the outputs of comparators 43 ₁ to 43n. The output L of bit adder 45 therefore represents the number of non-empty metering hoppers.

The subtracter 46 calculates the total number N of hoppers during load movement set in the number of hoppers during load movement setter 51, which will be described later.
The output L of the bit adder 45 is subtracted.

Therefore, the output (NL) of the subtractor 46 is
Represents the number of empty weighing hoppers.

Divider 4 of all hoppers target total weight calculation circuit 47
8 divides the set combination weight W set in the combination weight setting section 32b by the predetermined combination number M of hoppers set in the combination number setting device 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.

The total number N of weighing hoppers during loading movement is set and stored in the total number N of hoppers during loading movement.

The multiplier 50 multiplies the output W/M of the divider 48 by the total number N of combined hoppers during cargo movement set in the total number of hoppers during cargo movement setting device 51.

Therefore, the output (W/M) of this multiplier 50
×N represents the sum of the weights of all weighing hoppers, that is, the target total weight of all hoppers when the weights of the contents in all weighing hoppers 16 ₁ to 16n are set to the target weight W/M.

The subtracter 53 of the empty hopper supply amount calculation circuit 52 subtracts the current total weight of the current total weight calculation circuit 41 from the target total weight of all hoppers of the multiplier 50.

Therefore, the output of the subtractor 53 represents the difference between the target total weight of all hoppers obtained by multiplying the target weight per piece by the number of weighing hoppers and the current total weight of all weighing hoppers including the currently empty hoppers. There is.

The divider 54 divides the output of the subtracter 53 by the output of the subtracter 46 representing the number of empty hoppers to calculate the amount of supply to be accommodated per one empty hopper, and outputs a signal representing this amount of supply. do.

Upon receiving the output of the divider 54, the feeder control device 55 controls each feeder to supply the object to be weighed to the empty weighing hopper so that the weight of the empty weighing hopper approaches the weight represented by the output of the divider. Control the amount.

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 feeder 11 and the circular feeder ₁₂ , and then to each weighing hopper _{16 1} via the intermediate hoppers 14 1 to 14n.
~16n, respectively, measuring instruments 17 ₁ ~1
7n.

Therefore, N total weighing hoppers 16 ₁ to 16
Among the n weighing hoppers, the objects to be weighed are already accommodated in the L weighing hoppers by each feeder, and the remaining (N-
L) weighing hoppers have been discharged and are in the latter state, each weighing hopper 16 ₁ to 16
The weight signals from each of the scales 17 ₁ to 17n corresponding to n are input to comparators 43 ₁ to 43n to detect whether or not they are empty, and a subtracter 46 indicates the number of empty hoppers (NL). A signal is output.

In addition, each weight signal is calculated by the current total weight calculation circuit 41.
are added to sum up the total weight of all non-empty hoppers at the moment.

From the all hopper target total weight calculation circuit 47, 1
Total number of hoppers loading the target weight per piece W/M N
Target total weight of all hoppers multiplied by (W/M) x N
is output.

The empty hopper supply amount calculation circuit 52 subtracts the total weight of L weighing hoppers that are not empty from the target total weight of all hoppers, and divides this by the number of empty hoppers (NL). Therefore, the result of this division is
This is the target weight for one empty hopper.

Based on the output of the divider 54, the feeder control circuit 55 adjusts the load of each feeder in the empty weigh hopper so that the amount of feeder fed to the empty weigh hopper approaches the weight represented by the output of the divider 54. Controls the amount of material to be weighed.

In this way, the object to be weighed is loaded into the empty weighing hopper.

The combination selection circuit 32 determines the combination weight of a predetermined number of combinations of M weighing hoppers based on the weight signals stored in the weighing value storage circuit 31 for all weighing hoppers 16 ₁ to 16n in a state where empty hoppers exist. is calculated for all different combinations, and a combination of weighing hoppers whose difference from the set combination weight W set in the combination weight setting section 32b is within an allowable range is selected, and a combination selection signal is sent to the discharge control device 33. do.

The discharge control device 33 opens the discharge gates of the M weighing hoppers designated by the combination sorting signal and causes them to be discharged into the collection chute 19. The objects to be weighed are grouped together in a collecting chute 19, and when a timing hopper 20 is opened, they fall into a packaging machine 21 and are packed into bags.

In this way, while the combined discharge is carried out in the presence of the empty hopper, the objects to be weighed are fed into the empty hopper based on the aforementioned control. Therefore, due to the combined discharge, an empty hopper exists again at this time, and the input control amount to this empty hopper is calculated in the same way as before, and during this time, the remaining hoppers are used to perform the next combination. will be done.

Thereafter, the combination weighing and feeding into the empty hopper are repeated in the same manner.

In this way, the amount of objects to be weighed to be fed to the empty weighing hoppers is always controlled so that the total weight of the objects contained in all weighing hoppers becomes the target total weight. If the sum of the weights of the stored items is greater than (W/M)×L, the remaining (N−
The amount of supply to L) empty hoppers is W/
is smaller than M, and the total weight of the contents in all weighing hoppers (N pieces) is controlled so that it approaches (W/M)×N.

Conversely, if it is smaller than (W/M) x L, the amount supplied to the remaining empty hoppers is controlled so that each is larger than W/M and the total sum approaches (W/M) x N. Ru.

Therefore, even if the number of weighing hoppers is small, the combination weight that always has an extremely small difference from the set weight is
You will get it.

Note that if a failure occurs in a weighing hopper, weighing machine, discharge gate, etc., the combination calculation cannot be performed for that weighing hopper, so this failure will be detected and the total number of hoppers set during load movement 51 will be automatically set.
The set number may be subtracted by the number of failed metering hoppers, or the set number may be changed manually.

In this way, the setting can be changed to the number of hoppers during load movement, so even if a failure occurs in the weighing hopper or the failure is recovered, and the number of hopper movements changes, the above multiplication, Since the number N used for subtraction changes, supply to the empty hopper can be controlled regardless of failure.

In the above embodiment, a case was explained in which the weighing hoppers 16 ₁ to 16n were used as combination hoppers, but as shown in FIG _.
~22 _2o may be provided and a storage hopper may be combined.

That is, two memory hoppers are provided for each weighing hopper, and the weighing hoppers 16 ₁ to 16n
The weighed objects are transferred to the discharge gates 18 ₁ to 1.
Any empty memory hopper 22 ₁ ~ by 8 _2o
22 _2o , and the weight signals of the M storage hoppers are combined by a combination selection circuit. Then, among the discharge gates 23 ₁ to 23 _2o , the discharge gates of the selected M storage hoppers are opened to discharge and collect them at the collection gate 19.

In this case as well, the feed rate of the feeder is controlled so that the feed rate to the empty storage hopper approaches the value calculated by the feed rate calculation circuit 52.

<Effects of the present invention> As explained above, in the combination weighing device of the present invention, the amount of the next supply to the empty combination hopper is controlled in a state where an empty hopper exists. The input control amount can be determined while there is an empty hopper without waiting for the hopper to be filled.
While the hoppers remain, the remaining hoppers can be used to select and discharge combinations, and during this time empty hoppers can be filled.
It is much more efficient than the method of No. 63152, which waits for all hoppers to be filled each time and selects a combination to discharge. In particular, combination weighing devices repeat the combination operation hundreds of thousands of times in a short period of time, so the time it takes to wait for all the hoppers each time accumulates and becomes an enormous amount of time, making it extremely efficient. Ru.

(b) Since the next feeding amount can be controlled without waiting for all hoppers to be filled, the next feeding can also be done faster than before, and this difference in time is similarly accumulated in repeated operations, resulting in extremely high efficiency. becomes.

(c) Furthermore, even if one or more hoppers break down during work, it can be handled simply by changing the number set on the total number of hoppers during load movement setting device 51.

(d) Similarly, by changing this set number, the number of hoppers can be freely changed depending on the type of object to be weighed.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a conventional combination weighing device, and FIG. 2 is a diagram showing the relationship between variations in the weight of items contained in the weighing hopper and variations in the combined weight.
FIG. 3 is a schematic configuration diagram showing a mechanism section of an embodiment of the present invention, FIG. 4 is a schematic configuration diagram showing a control section thereof,
FIG. 5 is a schematic configuration diagram showing another embodiment of the mechanism section. 11... Feeder, 12... Circular feeder, 13
₁ to 13n... feeder, 16 ₁ to 16n... weighing hopper, 17 ₁ to 17n... measuring instrument, 18 ₁ to 1
8 _2o ...Discharge gate, 19...Collection chute, 2
2 ₁ ~22 _2o ...Memory hopper, 23 ₁ ~23 _2o ...
...Discharge gate, 30...Combination discharge device, 31...
...Measurement value storage circuit, 32...Combination selection circuit, 3
3... Emission control device, 40... Supply amount control circuit,
41... Current total weight calculation circuit, 42... Empty hopper number detection circuit, 47... All hopper target total weight calculation circuit, 52... Empty hopper supply amount calculation circuit,
55...Feeder control circuit.

Claims (1)

[Scope of Claims] 1: a plurality of feeders that respectively feed objects to be weighed to a plurality of hoppers; a plurality of scales that weigh objects to be weighed to be fed to each of the hoppers; A combination weighing device that is equipped with a combination discharging device that selects a combination of objects to be weighed housed in a hopper and discharges the objects to be weighed from a hopper that corresponds to the selected weight value. The target weight per hopper is calculated by dividing the set combination weight value by the preset number of combinations.
an all-hopper target total weight calculation circuit 47 that calculates the target total weight of all hoppers by multiplying the target weight per piece by the total number of all hoppers being loaded; and a weight signal for all the hoppers including the currently empty hoppers. A current total weight calculation circuit 41 calculates the current total weight by adding the total weight of the current total weight, and detects the number of empty hoppers by comparing each weight signal for all the hoppers with a value set in a zero setting device. Empty hopper number detection circuit 42
The total weight output from the current total weight calculation circuit 41 is subtracted from the target total weight of all hoppers output from the target total weight calculation circuit 47, and the difference between the two is calculated. an empty hopper supply amount calculation circuit 52 that calculates the supply amount that should be accommodated per empty hopper by dividing it by the number of empty hoppers output from the empty hopper number detection circuit 42 and outputs a supply amount signal; Based on the supply amount output signal calculated by the empty hopper supply amount calculation circuit 52, the amount of objects to be weighed by the corresponding feeders to each of the empty hoppers is adjusted to approach the calculated supply amount. A combination weighing device characterized by comprising a feeder control device 55 that controls.