JP3420816B2 - Bad hopper detection method in combination weigher - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to so-called "combination scales" for combining and weighing the objects to be weighed in a plurality of hoppers, each of which has a different storage capacity, when the objects to be weighed are packed in predetermined amounts. In the above, the present invention relates to a detection method for detecting a defective hopper that does not perform a predetermined function among the plurality of hoppers.

[0002]

2. Description of the Related Art A combination weigher has a plurality of hoppers for temporarily accommodating the objects to be weighed at the time of weighing, and supplies the objects to be weighed with a predetermined weight variation to each of the plurality of hoppers.
By combining the measured values of the objects to be weighed in each hopper with different storage capacity, find the combination that gives the desired weight to be packed in one bag or the weight within the allowable range that is the closest to it, and then obtain these combinations. It is configured such that each of the hoppers constituting the above is selected and the objects to be weighed contained therein are discharged to the bagging device side.

[0003]

However, when performing actual combination weighing in an actual combination weigher, the hoppers such as the weighing hopper and the feed hopper may be clogged, or the gate opening / closing operation of the hopper may be defective, or the weighing may be defective. .

When such a situation occurs, in the automatic combination weigher, the object to be weighed is accumulated in the supply device such as the supply conveyor on the upstream side of the combination weigher, or the discharge conveyor on the downstream side of the combination weigher, A processing device such as a bagging device may be in a standby state, and in the case of improper weighing, a bagged product having an excess or deficiency in weight is formed. In particular, when the above situation occurs in an automatic combination weigher, a large amount of objects to be weighed accumulate in the supply means and the like, or the supply means itself is restored, or reprocessing of defective products that are continuously discharged in a defective state, etc. It takes a lot of time, and the influence of the essential failure is greatly amplified, which is a particularly serious situation.

The conventional combination weigher has a weighing hopper,
In order to detect the gate opening / closing operation failure in the feed hopper, there are some equipped with sensors such as photoelectric tubes or limit switches, but depending on the type of object to be weighed,
Damage or stain these sensors in a short time,
In fact, it was often useless. Further, arranging these sensors and the like tends to increase the number of parts, complicate the control device, raise the product price, and lower the reliability.

The present invention has been made in view of the above situation, and an object thereof is to provide a method for detecting a hopper defect such as a metering defect or a gate opening / closing defect.

[0007]

According to a first aspect of the present invention, there is provided a method for detecting defective hoppers in a combination weigher, which comprises a plurality of weighing devices for accommodating an object to be weighed in combination weighing and opening a gate after the combination weighing. A hopper and a feed hopper for supplying the objects to be weighed to the weighing hopper,
A defective hopper detection method for detecting a defective hopper in a combination scale for combining and weighing the respective measured values of the plurality of weighing hoppers, wherein when the objects to be weighed are fed from the feed hopper to the weighing hopper, When the weighing value is not within the predetermined range, check whether the weighing values of other weighing hoppers tend to decrease with respect to the previous weighing values,
If there is no decreasing tendency, the feeding value of the feed hopper that supplies the object to be weighed to the weighing hopper does not fall within the prescribed range, or the feeding function of the feeding hopper is defective, or the weighing function of the weighing hopper is abnormal. It is characterized by determining that.

In the method according to the first aspect of the present invention, the predetermined range is determined mainly by a value obtained by dividing the average value of the objects to be weighed into the weighing hopper or the target weight value by the number of weighing hoppers. Is preferable for surely detecting.

In the method according to the first aspect of the present invention, the fact that the other weighing hoppers are adjacent weighing hoppers is more reliable in detecting defective hoppers in view of the tendency of supply of the objects to be weighed in the combination weigher.

A defective hopper detection method in a combination weigher according to a second aspect of the present invention is to provide a plurality of weighing hoppers for accommodating an object to be weighed in combination weighing and opening a gate after combination weighing to discharge the object to be weighed. A method for detecting a defective hopper in a combination scale that combines and weighs the measured values of the plurality of weighing hoppers. When the weighing value of the next weighing combination of the weighing hopper is about twice as large as the previous weighing value, it is determined that the discharge function of the weighing hopper has a defect. To do.

[0011]

According to the method for detecting defective hoppers of the combination weigher according to the first aspect of the present invention, the tendency of the combination weigher to show the same tendency in all the weighing hoppers is utilized, and the specific weighing hopper is used. Is not within the predetermined range, and only when other weighing hoppers do not tend to decrease compared to before, whether the feeding operation of the feed hopper is defective,
Alternatively, it can be determined that an abnormality has occurred in the weighing function of the weighing hopper, and the hopper having the malfunction in the combination weighing can be reliably identified, and the function having the malfunction can also be reliably identified. Therefore, the recovery operation of the combination weigher can be performed quickly, and the adverse effect resulting from the defective operation can be minimized.

Further, according to the defective hopper detection method for the combination scale according to the second aspect of the present invention, the combination scale has the basic property that the objects to be weighed within a predetermined range are supplied each time. If the weighing value of the weighing hopper selected in combination weighing becomes about twice as much as the previous weighing value, the previous weighing object remains without being discharged to the weighing hopper. It is possible to reliably identify the hopper that is malfunctioning in combination weighing,
Further, since the function causing the defect can be specified with certainty, the recovery operation of the combination scale can be performed quickly, and the adverse effect caused by the defective operation can be minimized.

[0013]

EXAMPLE An example in which the defective hopper detection method for a combination weigher according to the present invention is actually applied to a combination weigher (combination weighing device) will be described below.

FIG. 1 is a conceptual diagram showing a schematic structure of an automatic combination scale for carrying out the defective hopper detection method of the combination scale according to the present invention, in which a part of the structure is omitted, and FIG. 2 is a combination scale shown in FIG. FIG. 3 is a block diagram showing the relationship between each configuration of FIG. 4 and a control device that incorporates a program for a method for detecting a defective hopper.

In FIG. 1, reference numeral 1 denotes a weighing hopper having an open upper surface and a gate 1a which can be opened and closed at its lower end. Although not shown as one in FIG. 1, the weighing hopper 1 has a conical shape. A total of 16 units are provided around the outer periphery of the dispersion feeder 4 of FIG. 1, and each of these weighing hoppers 1 (1A to 1Q) is provided with
As shown in FIG.
An object to be weighed (for example, candy or the like) is supplied via the vibration feeder 3. Therefore, in the case of this embodiment, the feed hopper 2 and the vibrating feeder 3 correspond to each of the weighing hoppers 1A to 1Q.
Each pair is provided between the dispersion feeder 4.

Then, the object to be weighed is supplied to the dispersion feeder 4 from the object feeding device 5 arranged above the conical steeple portion of the dispersion feeder 4. Further, reference numeral 13 in FIG. 1 is a level sensor for detecting the bulk of the object to be weighed on the rectilinear vibration feeder 3.

As a result, the above 16 weighing hoppers 1A to
To 1Q, an object to be weighed is supplied from an object feeding device 5 via the dispersion feeder 4, the vibrating feeder 3 around it, and the feed hopper 2.

Below the weighing hoppers 1A to 1Q, a funnel-shaped collecting chute 6 whose peripheral edge is located below each of the weighing hoppers 1A to 1Q is arranged. A packaging machine 8 for packaging the objects to be weighed selected by the combination weighing is arranged via the collective funnel 7.

As a result, when the objects to be weighed which are accommodated in the weighing hopper 1 selected by the combination are discharged from the weighing hopper 1, they are arranged below them via the collecting chute 6 and the collecting funnel 7. Slipped into the packaging machine 8,
The packaging machine 8 is adapted to perform packaging such as bagging.

In the case of the present embodiment, this combination scale has a central processing unit (CPU) at one end, as shown in FIG.
The drive circuit 10a of the control device 10 connected to the 10c is connected to the gate drive device 11 and the feed hopper 2 of each of the weighing hoppers 1 described above.
Is electrically connected to the weighing hopper 1, and the weighing sensor 12 provided in the weighing hopper 1 is connected via the A / D converter 10b.
It is connected to the central processing unit (CPU) 10c.

Further, the vibration control circuit 10f is electrically connected to the conveying means of the dispersion feeder 4 and the vibration feeder 3.

The central processing unit (CPU) 10c is
A storage device (PROM) 10d containing a program for executing the defective hopper detection method according to the present invention, and various data.
A storage device (RAM) 10e is connected to store the target weight value of the packed product, the allowable range of the weighing value of each weighing hopper, the weighing value of each weighing hopper in the previous multiple weighing cycles, etc. .. Further, this control device 10 is
The operation setting display section 10A for performing the operation of (1) and setting or displaying of the above various data is provided.

Thus, the present combination scale configured as described above operates as follows when performing the combination measurement, and implements the defective hopper detection method according to the present invention.

That is, as shown in the flow chart of FIG. 3, first, prior to the combination weighing, when the main switch of the combination weighing is turned on, initialization is performed (step 1), and then the control device 10 is started. On the other hand, the weighing hopper 1 described above
Various data (various parameters) such as the allowable value of the weighing value (1A to 1Q), the target weight value of the packed product, etc. (various parameters) are set using the keyboard (not shown) of the operation setting display section shown in FIG. Step 2).

After the above setting is completed, the operation start switch of the combination weigher is turned "ON". By this operation, the object to be weighed is dispersed from the object to be weighed object feeding device 5 under the control of the controller 10. The objects to be weighed that have been conveyed to the feeder 4 are respectively fed to the vibrating feeder 3,
Each of the weighing hoppers 1A to 1A through the supply hopper 2
It is supplied to 1Q with a predetermined weight variation (step 3).

As described above, when the objects to be weighed are supplied to the respective weighing hoppers 1A to 1Q, the control device 10 performs the combination weighing, and the combination closest to the target weight value within the allowable range of the target weight value. The weighing hopper 1 according to step 1 is selected (step 4). The control device 10 controls each of the selected weighing hoppers 1
It is judged whether or not the total value of the measured weight values is within the allowable range of the target weight value (which means the target weight value of the product to be packed) (step 5). The objects to be weighed in the weighing hopper 1 are discharged to the collecting chute 6 side below (step 6). At this time, the weighing value of each weighing hopper 1 (1A to 1Q) is stored in the storage device (RAM) 10e of the control device 10.

Then, to the emptied weighing hopper 1, the above-mentioned object to be weighed is automatically supplied under the control of the controller 10 (step 7).

Next, in the second and subsequent combination weighing steps, the control device 10 causes each of the weighing hoppers 1A to 1A to perform the timing when it is estimated that the supply of the objects to be weighed to each of the weighing hoppers 1 is estimated to be completed in time. Each measured value of 1Q is stored in the storage device (RA
M) Check if it is within the allowable range of the weight value stored in 10e. That is, it is checked whether the weighing values of the respective weighing hoppers 1A to 1Q are within a predetermined range centered on a value obtained by dividing the average value of the objects to be weighed into the weighing hopper or the target weight value by the number of weighing hoppers. (Step 8). As a result,
If it is within the allowable range, it is checked whether or not the weighing value of the next-supplied weighing hopper 1 is approximately twice the previous weighing value (step 9).

Then, in "(step 8)", if there is a weighing hopper 1 whose weighing value is out of the predetermined range, weighing of another weighing hopper 1 (two adjacent weighing hoppers in this embodiment) is performed. It is checked whether or not the value tends to decrease with respect to the weight value before that (for example, the previous time) (step 10), and when the value does not tend to decrease, the object to be weighed is fed to the weighing hopper 1 which is out of the predetermined range. It is determined that the feeding operation of the feeding hopper 2 is defective or that the weighing function of the weighing hopper 1 is abnormal.
(Step 11), the operation of the combination scale is temporarily stopped and an alarm is issued (Step 12).

Therefore, if the feeding operation of the feed hopper 2 is defective, it is possible to prevent the objects to be weighed from accumulating in the feed hopper 2 or the weighing hopper 1 thereof. Further, if there is an abnormality in the weighing function of the weighing hopper 1, it is possible to immediately stop the defective weighing operation of the combination weigher and prevent an incomplete weighing product from occurring.

By the way, in the above "(step 10)", if the other weighing hoppers 1 are in a decreasing tendency, the process shifts to "(step 9)".

In the above "(step 9)",
If there is a weighing hopper 1 whose weighing value is about twice as much as the previous weighing value, it is determined that the discharging function of the weighing hopper 1, for example, the opening / closing operation failure of the gate 1a of the weighing hopper 1 has occurred. (Step 13) Then, the operation of the combination scale is temporarily stopped and an alarm is issued (Step 12).

Also in this case, it is possible to prevent the objects to be weighed from accumulating in the weighing hopper 1 having a defective discharge function, and to prevent the generation of incompletely weighed products. can do.

In the above "(step 9)",
If there is not about twice as much weighing hopper 1 as the previous weighing value, the process proceeds to "(step 4)" and the above-mentioned combination weighing is performed.

[0035]

As described above, according to the defective hopper detection method in the combination weigher according to the first and second aspects of the present invention, the hopper having the clogging, the gate opening / closing operation failure, or the weighing failure can be detected immediately and accurately. Therefore, it is possible to effectively prevent the accumulation of the objects to be weighed, the generation of the poorly weighed products, and the like, which have occurred conventionally.

Therefore, as compared with the conventional combination weigher, it is possible to provide a reliable combination weigher that is resistant to troubles.

Further, since the detecting means (sensor) or the like which is conventionally provided for detecting the clogging of the object to be weighed or the defective opening / closing operation of the gate is not required, the number of parts is reduced, and this point is also reliable. It is possible to provide a combination weigher having high property and capable of reducing manufacturing cost.

[Brief description of drawings]

FIG. 1 is a conceptual diagram with a part omitted showing a schematic configuration of a combination scale for carrying out a defective hopper detection method according to the present invention.

FIG. 2 is a block diagram showing a relationship between each configuration of the combination weigher shown in FIG. 1 and a control device.

3 is a flowchart showing each step of the defective hopper detection method according to the first embodiment of the present invention applied to the combination weigher shown in FIG.

[Explanation of symbols]

1 ... Weighing hopper 1a ... gate 2… Feed hopper

Claims (4)

(57) [Claims] 1. In combination weighing, a plurality of weighing hoppers for storing objects to be weighed and for discharging the objects to be weighed by opening a gate after combination weighing, and a feed hopper for supplying the objects to be weighed to the weighing hoppers, respectively. A method for detecting a defective hopper in a combination scale for combining and weighing the respective measured values of the plurality of weighing hoppers, wherein the weighing hopper is fed when an object to be weighed is supplied from the feed hopper to the weighing hopper. When the weighing value of is not within the predetermined range, it is checked whether the weighing values of the other weighing hoppers have a decreasing tendency with respect to the weighing values before that. Determining that the feed hopper feeding operation to supply the objects to be weighed to the weighing hopper that is not within the range is defective or that the weighing function of the weighing hopper is abnormal. Detecting method of defective hopper in combination scale. 2. The predetermined range is centered on a value obtained by dividing an average value of the objects to be weighed into the weighing hopper or a target weight value by the number of weighing hoppers.
A method for detecting defective hoppers in the described combination scale. 3. The defective hopper detection method for a combination weigher according to claim 1, wherein the other weighing hoppers are adjacent weighing hoppers. 4. In combination weighing, a plurality of weighing hoppers for accommodating the objects to be weighed and for opening the gate after the combination weighing to discharge the objects to be weighed, and a feed hopper for respectively supplying the objects to be weighed to the weighing hoppers. , A defective hopper detection method for detecting a defective hopper in a combination scale for combining and weighing the respective measured values of the plurality of weighing hoppers, wherein the weighing value of the next combination weighing of the weighing hopper selected in the combination weighing is A method for detecting a defective hopper in a combination weigher, which comprises determining that a discharge function of the weighing hopper is defective when the measured value is about twice as much as the previous measured value.