JPH0577250B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field of the Present Invention> The present invention efficiently weighs objects to be weighed, such as confectionery, fruits, vegetables, etc., whose individual weights vary, in a set amount at once. It relates to a combination weighing device used for

<Prior Art> (Fig. 6) A combination weighing device is used to collect a set amount of objects to be weighed whose individual weights vary.

In this type of combination weighing apparatus, _for example, as shown in FIG _. and each feeder 3 _-1 to 3
The objects to be weighed supplied from _-o to the corresponding weighing hoppers 4 _-1 to 4 _-o are
A combination close to or equal to the set amount is selected, and the selected objects to be weighed are collected and discharged via the collection chute 5.

In order to select this combination accurately and efficiently, it is necessary to ensure that the amount of objects to be weighed from each feeder 3 _-1 to 3 _-o to the weighing hoppers 4 _-1 to _{4 -o} is always at a predetermined weight (i.e., The value must be very close to the value obtained by dividing the set amount by the target number of combinations.

For this reason, the sending force parameters (for example, vibration amplitude and vibration time) are controlled for each feeder 3 _-1 to _{3 -o} .

That is, for each feeder 3 _-1 to _{3 -o} , a new feeding force parameter is calculated based on the feeding force parameter up to the previous feeding time and the actual feeding amount corresponding to the feeding force parameter. The feeder is driven to constantly feed a predetermined amount of objects to be weighed.

However, the amount of feed from the feeders 3 _-1 to _{3 -o} varies greatly depending on not only the feeding force parameters of each feeder but also the layer thickness of the object to be weighed on the feeder. Therefore, conventionally, this layer thickness is detected by a light emitting/receiving device or the like (not shown), and a predetermined amount of the object to be weighed is always on the feeder or on the circular feeder 2 (the object to be weighed on the circular feeder 2). The layer thickness of each feeder 3 is
_-1 to 3 _-o The drive of the conveyor 1 is controlled as shown in (because it is approximately proportional to the layer thickness of the object to be weighed on -o).

<Problems to be Solved by the Present Invention> However, the objects to be weighed to the conveyor 1 are generally supplied manually in many cases, and the supply of the objects to the circular feeder 2 is not necessarily stable.

Therefore, the supply of the objects to be weighed on the conveyor 1 may be delayed for a relatively long time, and the layer thickness of the objects to be weighed on the circular feeder 2 may continue to be insufficient for a long time. In such a situation, the amount of material to be weighed from each feeder _3-1 to 3 _-o to the weighing hopper _4-1 to 4 _-o will always be insufficient for the predetermined amount. _The feeding force _parameter calculated by
Since the objects to be weighed are supplied from the to the weighing hoppers _4-1 to 4 _-o several times, the weighing hoppers _4-1 to 4 _-o are
An abnormally large amount of objects to be weighed is supplied. For this reason, some weighing hoppers that cannot be used for combination selection may occur, and the next feeding force parameter may become _{abnormally small} due to the supply of a large amount of objects to be weighed. Weighing hopper 4 _-1 ~
4 _- The supply amount of the object to be measured for -o becomes extremely large.

Therefore, there has been a problem in that the accuracy and efficiency of combination selection are significantly reduced due to insufficient supply to the feeders 3 _-1 to _{3 -o} .

<Object of the present invention> The present invention has been made in view of the above circumstances, and is intended to prevent the accuracy and efficiency of combination selection from significantly decreasing even if there is a shortage in the amount of objects to be weighed to the feeder. The purpose is to provide a combination weighing device.

<One Embodiment of the Present Invention> (FIGS. 1 to 5) Hereinafter, one embodiment of the present invention will be described based on the drawings.

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

In FIG. 1, reference numeral 11 is a conveyor that sequentially conveys objects to be weighed to a circular feeder 12. N intermediate hoppers 14 _-1 to 14 _-o are arranged in a circle below the periphery of the circular feeder 12, and objects to be weighed are supplied through the feeders 13 _-1 to 13 _-o , respectively.

Note that the circular feeder 12 includes a conveyor 1.
Light projecting/receiving devices 12a and 12b are provided for detecting the layer thickness of the object to be weighed conveyed from 1 to 1.

Weighing hoppers 16 _-1 to 16 _-o are provided below the intermediate hoppers 14 _-1 to 14 _-o , respectively.
When the discharge gates 15 _-1 to _{15 -o} are opened, the objects to be weighed accommodated in the intermediate hoppers 14 _-1 to 14 _-o fall and are accommodated in the weighing hoppers 16 _-1 to 16 _-o , respectively.

Weighing devices 17 _-1 to 17 _-o are installed in the weighing hoppers 16 _-1 to 16 _-o , respectively. Measuring device 17
_-1 to 17 _- o weigh the objects to be weighed accommodated in the weighing hoppers _16-1 to 16 _-o , respectively, and output the weighed values.

A collection chute 19 is installed below the weighing hoppers 16 _-1 to 16 _-o . Weighing hopper 16 _-1
~16 The objects to be weighed stored in _-o are placed in weighing hopper 1.
When the discharge gates 18 _-1 to 18 _-o of 6 _-1 to 16 _-o are opened, the waste falls 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.

In the control section, as shown in FIG.
The measured values from 7 _-1 to 17 _-o are transferred to the combination discharge device 24.
and sent to the sending force parameter calculation circuits 29 _-1 to 29 _-o .

The combination discharge device 24 includes each measuring device 17 _-1 to 17
_- Select a combination that is equal to or close to the set weight by combining the weighing values from o, open the discharge gate of the weighing hopper containing the selected object to be weighed, and discharge the selected object to be weighed. Then, the discharge gate of the intermediate hopper corresponding to the empty weighing hopper is opened to accommodate the next object to be weighed.

For this reason, the combination discharge device 24, for example,
It is configured as shown in the figure.

In FIG. 3, the measured values from the measuring instruments 17 _-1 to 17 _-o are sent to the measured value storage circuits 25 _-1 to 25 _-o , stored therein, and sent to the combination selection circuit 26.

The combination selection circuit 26 includes the measurement value storage circuit 25 _-1
~ _{25 -A} combination calculation unit 26 that calculates all different combination weights based on the measured values stored in -o.
a, and a weight setting section 2 that stores and stores the set weight Wa.
6b, the combination weight of the combination calculation unit 26a and the set weight Wa of the weight setting unit 26b are compared, a combination that is equal to or close to the set weight Wa is selected, and a combination selection signal is output to the discharge control circuit 27. 26c.

Upon receiving the combination selection signal, the discharge control circuit 27 opens a designated one of the discharge gates 18 _-1 to 18 _-o , 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 to open the door.

Furthermore, this discharge control circuit 27 sends a feeder drive circuit 42 _-1 which will be described later to supply a supply request signal for driving the feeder corresponding to the intermediate hopper that has already been discharged.
~42 Output to _-o .

28 divides the set weight Wa of the weight setting section 26b by the target number of combinations M, and calculates the division result (Wa/
This is a divider that outputs M) to the sending force parameter calculation circuits 29 _-1 to 29 _-o .

Note that this division result (Wa/M) is the target supply amount of the objects to be weighed from each feeder 13 _-1 to 13 _-o .

On the other hand, the feeding force parameter calculation circuit 29 _-1 to 29 _-o
In order to bring the supply amount of the objects to be weighed from each feeder _13-1 to _13-o closer to the target supply amount (Wa/M), each time the objects to be weighed are fed to the weighing hopper, A new feeding force parameter is calculated every few times of measurement based on each input weight value and the feeding force parameter of the feeder at the time of feeding.

FIG. 4 is a diagram showing an example of the sending force parameter calculation circuit 29 _-1 .

In FIG. 4, the measured value from the measuring device 17 _-1 is sent to the adder 30 _-1 every time a measurement is performed. The adder _30-1 adds the input weight value to the value stored in the weight accumulation memory _31-1 , and the addition result is sent to the weight accumulation memory _31-1 via the switch _32-1 . will be newly memorized.

On the other hand, the adder 33 _-1 adds the value stored in the feeding force parameter accumulation memory 34 _-1 and the current feeding force parameter, and the addition result is sent to the feeding force parameter accumulation memory via the switch 35 _-1 . It is newly stored in container 34 _-1 .

Note that the feeding force parameter here is a parameter based on the vibration amplitude and vibration time of the vibrator of the feeder, and the feeding force when a predetermined vibration amplitude and vibration time are given to the vibrator is 100%,
It is expressed as a percentage.

The divider 36 _-1 divides the stored value ΣF of the sending force parameter integration storage 34 _-1 by the stored value ΣW of the weight integration storage 31 _-1 . The multiplier 37 _-1 divides the target supply amount Wa/M by the division result from the divider 36 _-1 .

Therefore, the _division output (ΣF/
ΣW)×(Wa/M) indicates a feeding force parameter for causing the supply amount from the feeder _13-1 to approach the target supply amount Wa/M.

The multiplication result from multiplier 37 _-1 is sent to switch 38
_-1 , it is stored in the sending force parameter memory 39 _-1 .

The switches 32 _-1 and 35 _-1 receive a hold signal from a hold circuit 44, which will be described later, and a predetermined period of time after the object to be weighed is placed in the weighing hopper 16 _-1 (i.e., the time until the weight value stabilizes). The logical sum with the weighing completion signal A input later is the AND circuit 40 _-1
The output pulse is taken by the AND circuit 40-1 and turned ON in synchronization with the output pulse of the AND circuit _40-1 . Further, the counter 41 _-1 outputs one pulse every time the output pulse of the AND circuit 40 _-1 is input a predetermined number of times (for example, four times), and turns on the switch 38 _-1 with this output pulse. let

Therefore, a new feeding force parameter is set every time the object to be measured is fed four times.

Other sending force parameter calculation circuits 29 _-2 to 29 _-o
The feeder drive circuits 42 -1 to 42 - are also configured in the same manner as described above, and the feeding force parameters of each feeding force parameter memory 39 _-1 to 39 _-o are stored in the feeder drive circuits 42 _-1 to 42 _- along with the supply request signal from the discharge control circuit 27. _o are respectively entered.

Among the feeder drive circuits 42 _-1 to 42 _-o , the feeder drive circuit designated by the supply request signal drives the feeder with a feeding force according to the feeding force parameter from the corresponding feeding force parameter storage device.

Further, the detection circuit 43 receives detection signals from the light emitters and receivers 12a and 12b provided on the circular feeder 12, and outputs an "H" level when the layer thickness of the object to be weighed on the circular feeder 12 is lower than a predetermined level. Outputs a shortage signal.

The shortage signal from the detection circuit 43 is sent to a hold circuit 44 and a conveyor drive circuit 50.

When the shortage signal from the detection circuit 43 is continuously input for a predetermined period of time or more, the hold circuit 44 controls the transmission force parameter calculation circuits 29 _-1 to 29 _-o.
The switches 32 _-1 to 32 _-o , 35 _-1 to 35 _-o and the switches 38 _-1 to 38 _-o are kept in the OFF state to stop calculation of new feeding force parameters.

For this purpose, the hold circuit 44, for example,
It is configured as shown in the figure.

That is, the shortage signal from the detection circuit 43 is sent to one input terminal of the AND circuit 45 and the inverter 48.
A pulse of a predetermined frequency from a rectangular wave oscillator 46 is input to the other input terminal of the AND circuit 45.

The pulse output of the AND circuit 45 is input to a time counter 47.

The time counter 47 outputs an "H" level pulse every time it receives a predetermined number of pulses (that is, a predetermined time elapses), and is reset by the "H" level output of the inverter 48.

The output pulse of time counter 47 is input to flip-flop 49.

The flip-flop 49 has its D input fixed at "H" level, and its inverted output serves as a "L" level hold signal to each AND circuit 40 _-1 to 40 of the sending power parameter calculation circuits 29 _-1 to _{29 -o} . _-o
is being sent to. Also, flip-flop 49
is also reset by the "H" level output of the inverter 48.

Further, the conveyor drive circuit 50 sends out a drive signal for driving the conveyor 11 while the shortage signal is being input.

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

The objects to be weighed conveyed by the conveyor 11 pass through the circular feeder 12, and then are transferred to the feeders _13-1 to 13-1.
13 _-o respectively intermediate hoppers 14 _-1 to 14
_-o , and is stored in each weighing hopper 16 _-1 to 16 _-o from intermediate hoppers 14 _-1 to 14 _-o , and weighed by scales 17 _-1 to 17 _-o , respectively.

The measured values from each measuring device 17 _-1 to 17 _-o are stored in the measured value storage circuit 25 _-1 to 25 _-o of the combination discharge device 24.
The combination selection circuit 26 selects a combination that is equal to or close to the set weight Wa.

The objects to be weighed in the weighing hopper designated by this selection signal are collected in the collection chute 19 when the corresponding discharge gate is opened by the discharge control circuit 27, and when the timing hopper 20 is opened, they are packaged. It falls into machine 21 and is packed into bags.

Next, combinations using the remaining weighing hoppers are selected, and combination discharge is performed in the same manner. During this period, the object to be weighed is also supplied by the discharge control circuit 27 to the intermediate hopper corresponding to the weighing hopper that has already been discharged, and the corresponding feeder drive circuit is activated by the supply request signal to discharge the object from the feeder. The object to be weighed is supplied to the finished intermediate hopper.

Thereafter, in the same manner, a weighing signal is outputted from the weighing device for the weighing hopper newly containing the object to be weighed, and the weighing hopper is continuously discharged and filled, and combination discharge is performed one after another.

The measured values from each of the measuring instruments 17 _-1 to 17 _-o are sent to the sending force parameter calculating circuits 29 _-1 to 29 _-o for each measurement while this combined measuring operation continues.

Here, the conveyance state of the objects to be weighed from the conveyor 11 is stable, and each time the shortage signal from the detection circuit 43 is input to the conveyor drive circuit 50,
The objects to be weighed are being rapidly fed from the conveyor 11 to the circular feeder 12, and the hold signals to each feeding force parameter calculation circuit _29-1 to _29-o are at the "H" level. There is.

Further, for example, it is assumed that the initial value F ₁ of the sending force parameter is stored in the sending force parameter storage device 39 _-1 .

Therefore, the weighed value W ₁ first input to the adder 30 _-1 is the weighed value of the object to be weighed that is fed by driving the feeder 13 _-1 according to the feeding force parameter F ₁ .

Every time the measurement completion signal A is input, the adder 30
The weighing values W ₁ , W ₂ , W ₃ , ... input to _-1 are
The values are added up sequentially and stored in the weight integration storage 31 _-1 . Further, the stored value _F1 of the sending force parameter storage _39-1 is also sequentially added by the adder _33-1 in synchronization with this, and
4 _-1 is accumulated and stored.

For example, when the fourth weighing value W ₄ is added, the counter 41 _-1 causes the switch 38 _-1 to be added.
turns ON, the stored value of weight accumulation memory 31 _-1
W ₁ +W ₂ +...+W ₄ and the stored value 4×F ₁ of the sending force parameter integration storage 34 _-1 are divided by the divider 36 _-1 , and the target supply amount Wa/W 4 is divided by the divider 36 -1.
The value multiplied by M, that is, [(4×F ₁ )/(W ₁ +W ₂ +...+W ₄ )] ×Wa/M is stored as the new sending force parameter F ₂ in the sending force parameter memory. 39 _-1 , and is input to the feeder drive circuit 42 _-1 , and is controlled so that the supply amount from the next time of feeder 13 _-1 approaches the target supply amount Wa/M.

This control is performed in exactly the same way for the other feeders 13 _-2 to 13 _-o , and the target supply amount Wa/
Objects to be weighed close to M are supplied.

Here, if the conveyance state of the object to be weighed from the conveyor 11 becomes unstable and the object to be weighed is not conveyed for a long time, the shortage signal from the detection circuit 43 will continue for a long time and be input to the hold circuit 44. Therefore, the hold signal remains at the "L" level until a predetermined level of the object to be weighed is supplied onto the circular feeder 12.

Therefore, during this time, the addition calculation of the weighed value and the feeding force parameter by each feeding force parameter calculation circuit 29 _-1 to 29 _-o is not performed, and the feeder is unable to feed the object to be weighed according to the feeding force parameter up to the previous feeding. It will be done.

Then, when the conveyance of the object to be weighed from the conveyor 11 returns to normal and the detection circuit 43 no longer sends out the shortage signal, the time counter 47 and flip-flop 49 of the hold circuit 44 are reset, and the hold signal is set to "H". “Go back to level.

For this reason, each sending force parameter calculation circuit 29 _-1 ~
29 _-o , the addition calculation of the weighing value and the feeding force parameter is restarted every time the weighing completion signal is input, and a new feeding force parameter is calculated every four measurements, and the object to be weighed is supplied using this feeding force parameter. is repeated.

<Other embodiments of the present invention> In the above embodiments, it is detected that the amount of objects to be weighed supplied from the transport conveyor 11 onto the circular feeder 12 continues to be insufficient for a predetermined period of time or more,
The feeding force parameters of all feeders _13-1 to 13 _-o were fixed, but this meant that a shortage in the amount of the object to be weighed was detected for each feeder _13-1 to 13 _-o , and the feeder The sending force parameter may be fixed individually for each case.

In addition, in the above embodiment, the shortage of the amount of the object to be weighed that is being fed onto the circular feeder 12 is detected by the light emitter/receiver, but this is not only possible with the light emitter/receiver, but also with the circular feeder, for example. The lack of weight of the object to be weighed on 12 may be detected by a measuring instrument.

<Effects of the present invention> Since the combination weighing device of the present invention is configured as described above, even if the feeder continues to be under-supplied with objects to be weighed, the feeding force parameters of the feeder are fixed during this period. When the supply amount to the feeder returns to normal, feeder power control is restarted.

Therefore, unlike in the past, abnormal fluctuations in the feeding force parameters due to insufficient supply of objects to be measured to the feeder are eliminated, and the accuracy and efficiency of combination selection are significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a mechanism section of an embodiment of the present invention, Fig. 2 is a block diagram showing a control section of an embodiment, and Figs. 3 to 5 show main parts of Fig. 2. The block diagram, FIG. 6, is a schematic diagram of a conventional combination weighing device. 11... Conveyor, 12... Circular feeder, 13 _-1 ~ 13 _-o ... Feeder, 14 _{-1 ~} 14
_-o ...Intermediate hopper, 16 _-1 to 16 _-o ...Measuring hopper, 17 _-1 to 17 _-o ...Measure device, 24 ...Combination discharge device, 29 _-1 to 29 _-o ...Feeding power parameter Arithmetic circuit, 42 _-1 to 42 _-o ... feeder drive circuit,
43...Detection circuit, 44...Hold circuit, 50
...Conveyor drive circuit.

Claims (1)

[Claims] 1. A plurality of feeders for transporting objects to be weighed; A detection means that outputs a shortage signal when the amount of objects to be weighed on the plurality of feeders becomes less than a predetermined amount; From the detection means a supply means for supplying objects to be weighed to the plurality of feeders in response to a shortage signal; a plurality of weighing hoppers each accommodating objects to be weighed from the plurality of feeders; provided for each of the plurality of weighing hoppers; A plurality of measuring instruments that output measured values according to the stored objects to be weighed; Based on the measured values from the plurality of measuring instruments, a combination that is equal to or close to a set amount is selected, and a combination that is equal to or close to the set amount is applied to the selected combination. a combination discharging means for collectively discharging corresponding objects to be weighed; a new means provided for each of the plurality of feeders to keep the amount of objects to be weighed from the feeder to the corresponding weighing hopper always close to a predetermined amount; a plurality of feeding force parameter calculating means each calculating a feeding force parameter based on the feed amount of the object to be weighed up to the previous feeding from the feeder and the feeding force parameter at the time of the feeding; a plurality of feeder driving means for driving the plurality of feeders according to the feeding force parameter calculated by the force parameter calculation means; when a shortage signal from the detection means is continuously input for a predetermined time or more; The calculation of new feeding force parameters by the plurality of feeding force parameter calculating means is stopped, the feeding force parameters used for the previous feeding of each feeder are held, and when the input of the shortage signal is stopped, the new feeding force parameters are A combination weighing device characterized by comprising: a hold means for restarting calculation of .