JP2002340658A - Weighing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the weighting stability, to enhance the weighing precision, and to allow a long article longer than a length of a weighing converyer to be weighted, when weighing the article of which the grounding length is shorter than that of the article. SOLUTION: This weighing equipment for weighing the weight of an article M continuously during conveying the article M with the weighing conveyer 1 is provided with an article detecting means 18 for detecting the article M of which the conveying- directional full length is longer than the conveying-directional grounding length, which is arranged in a conveying route, and which is under a conveyed condition, a weight detector 5 for detecting the weight of the article M to output an weight signal, a weight determining means 14 for determining a weight value of the article M based on the weight signal, a storage means 12 for storing at least the grounding length of the article, the length of the weighing conveyer, a processing speed of the weighing equipment, and a weight value determining condition for determining the weight value by the weight determining means, and a setting means 16 for setting the weight value determining condition based on the grounding length, the length of the weighing conveyer, and the processing speed stored in the storage means 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weighing method for continuously measuring the weight of an article, such as an article wrapped in a film, having an overall length longer than a contact length in a transport direction while being transported by a weighing conveyor. Related to the device.

[0002]

2. Description of the Related Art Conventionally, when an article is continuously weighed while the article is being conveyed by a weighing conveyor, the following has been performed. As shown in FIG. 6, an intake conveyor 6, a weighing conveyor 1, and a distribution conveyor 7 are arranged upstream of the article transport path. A photoelectric sensor 18 (article detecting means) is arranged near the front end of the weighing conveyor 1 so as to detect that an article is carried into the weighing conveyor 1 from the intake conveyor 6. The articles conveyed from the take-in conveyor 6 are weighed by the weighing conveyor 1, and sorted by the sorting conveyor 7 into defective weight articles and weighing correct articles according to the weighing results.

[0003] A load cell (weight detector) is connected to the weighing conveyor 1, and articles M to be conveyed by the weighing conveyor are connected.
, And the weight is electrically converted and output as a weight signal. This weight signal is amplified by an amplifier,
The amplified analog output is converted into a digital signal by an A / D converter. A DSP (Digital Signal Processor) is connected to the A / D converter, and processes the weight signal converted into the digital signal. This DS
P is configured as a low pass filter and filters the digitized weight signal. In addition,
This DSP is set to various filter characteristics such as an FIR type low-pass filter or a filter having a different cutoff frequency set in the post-storage means.

[0004] The weighing device is provided with a control unit (CPU). The control unit includes a weight determining unit that determines a weight value based on the weight signal filtered from the DSP, a determining unit that determines the weight value from the weight determining unit as a positive weight, a light weight, or an excessive weight, It comprises a storage unit in which the weighing conditions are stored, and a setting unit for calculating and setting the weighing conditions stored in the storage unit.

The weight determining means determines a weight value based on the weighing conditions stored in the storage means based on the filtered weight signal from the DSP. The weighing conditions are calculated by the setting means from the article length K, the weighing conveyor length L, and the weighing conveyor speed V input from the input means connected to the control section, and stored in the storage means.

The control unit is connected to a distribution control unit for controlling the distribution conveyor 7, and the defective articles judged to be light or excessive by the judgment means are stored in the storage means. Items are sorted according to sorting conditions for each type of article. A sorting unit (not shown) is provided on the sorting conveyor.
For example, it has an arm type distribution unit. The distribution condition is the type of the distribution unit (arm type, drop type, air type, etc.) and the time from when the photoelectric sensor 18 detects an article to when the distribution unit starts operating when the article is defective. Time VT.

Next, the operation of weighing articles with the above configuration will be described. First, when an article is detected by the photoelectric sensor 18, P
1 (t1) After that, the articles start to move onto the weighing conveyor 1, and the load on the weighing conveyor 1 starts. Thereafter, the article is completely transferred to the weighing conveyor and the load is completed P2 (t
2). The time during this is the transfer time RT. Thereafter, the article reaches P3 (t3) after the set filter time FT and after the elapse of the sampling time FST. This position is where the front end of the article has reached the end of the weighing conveyor 1. The filter time FT is a time constant (delay time) determined by the type of the filter stored in the storage means. The sampling time FST is, for example, a time corresponding to three times of the weight signal output from the set filter. This is because the DSP performs sampling at a predetermined sampling cycle, so that the weight signal is not output continuously, but is output intermittently at the sampling cycle. If the weight signal is stable within a predetermined range (for example, a width of ± 0.1 g) within the sampling time FST, it is determined that the weight signal is stable, and the weight value is averaged over three times. If it is not within the above-mentioned predetermined range, it is determined as unstable by the determining means, and is eliminated by the downstream sorting device. This time is so short that it can be considered a constant. Note that the sum of the sampling time FST and the filter time FT is the weighing stability time WT, and the sum of the transfer time RT is the weight value acquisition time ZT.

[0008] Thereafter, the article is transferred to the sorting conveyor 7, and the article determined to be defective is removed at P4 (t4). This time is the distribution time VT. Further, the time equal to the transfer time RT is the re-detection inhibition time UT. The re-detection prohibition time is a time during which the detection of the article within a predetermined time after the photoelectric sensor 18 detects the front end of the article is ignored. This is because when the article is a package and the packaging material is partially transparent, it is recognized that the article has passed on the way, even though the article has passed, and then the opaque packaging material part This prevents erroneous detection such as detecting that the article has begun to pass.

Further, there is a two-seater detection time DT. During this time, if the photoelectric sensor 18 detects the first article again after detecting the first article, the next article is transferred to the weighing conveyor even though the weighing of the first article is not completed. As a result, the first article is weighed while the two articles are on the weighing conveyor 1, so that it is time to detect an erroneous weighing. This filter time FT, sampling time FST, weight value acquisition time ZT,
The distribution time VT, the re-detection prohibition time UT, the two-seater detection time DT, and the like are stored in the storage means as weighing conditions.

Hereinafter, the setting of each time will be described. In this case, the weighing capacity N, the article length K in the transport direction, and the length L of the weighing conveyor 1 are used. First, when weighing is performed with the weighing capacity N, the speed V of the weighing conveyor 1 is obtained by the following equation (1). V = L × N (1) Next, a transfer time RT and a re-detection prohibition time UT are obtained by the following equation (2). RT = UT = K / V Next, the weighing stabilization time WT is obtained. WT = L / V-RT = L / V-K / V = (LK) / V (2)

Next, a constant sampling time FST is subtracted from the weighing stabilization time WT obtained by the above equation (2), a time during which the maximum filter time FT is allowed is calculated, and a maximum filter time FT shorter than that time is selected. I do. This filter time FT is a time uniquely determined by the characteristics of the filter stored in the storage means. In the case of a low-pass filter, generally, a filter having a lower cutoff frequency has a response time which is a time constant of the filter, that is, a filter time. FT is longer. The lower the cutoff frequency is,
Since the high frequency component is not passed, the output after filtering is stabilized. That is, the relationship of the following equation (3) holds. FT ≦ WT−FST (3) Accordingly, the weight value capturing time ZT is calculated by the following equation (4). ZT = RT + FT + FST (4) Conventionally, measurement has been performed in this manner. In this case, one cycle time ST of measurement is ST = 1 / N (5) = L / V (6) = DT (7), which is equal to the two-seater detection time DT. That is, conventionally, since the article length K is shorter than the weighing conveyor length L, the two-seater detection time DT is equal to the weighing cycle ST.

[0012]

However, the conventional method has the following problems in the following cases. (A) For example, when the grounding length K1 of the article is shorter than the article length K, such as an article having a sealed portion (ear) at each tip end in a pack product wrapped with a film, the filter time FT is calculated by the above equation. When it is calculated, only the short filter time FT can be selected despite the fact that the load time is originally short and the weighing stability time WT is long. This means that only a filter having low output stability can be set, so that the measurement stability is poor and the measurement accuracy is poor. (B) To solve (a), if the weighing conveyor length L is increased, the calculated filter time FT can be increased, so that the stability of weighing increases, but at the same time, as expressed in the above equation (1). Since the weighing capacity is reduced, it is necessary to increase the weighing conveyor speed V at the same time. If this occurs, a desired filter time FT cannot be obtained, and a vicious cycle occurs in which the weighing conveyor length L is increased. When the length L of the weighing conveyor is increased, the transport path of the article is correspondingly increased, and the attitude of the article is changed during the transport, thereby lowering the stability of the transport attitude. In addition, the smoothness of the weighing conveyor is required as the length increases, and the processing cost increases. Above all, the increase in the length L of the weighing conveyor increases the weight of the weighing conveyor itself, which lowers the natural frequency of the weighing system composed of the load cell and the weighing conveyor, and is greatly affected by external vibrations. It will be easier. In addition, as the speed of the weighing conveyor increases, the durability of the conveyor itself decreases,
The possibility of the meandering of the belt increases, the stability of the conveyance posture of the articles decreases, and the adverse effect on the stability of weighing is increasing. (C) In the case where the article length K is longer than the weighing conveyor length L, the above equation (2) does not hold, so that it was conventionally impossible to set.

According to the present invention, when weighing an article having a ground contact length shorter than the article length, the weighing stability is increased, the weighing accuracy is improved, and even an article longer than the weighing conveyor length can be weighed. It is still another object of the present invention to solve the problem caused by the setting for enabling the weighing.

In order to achieve the above object, a weighing apparatus according to claim 1 of the present invention continuously measures the weight of an article while the article is being conveyed by a weighing conveyor, wherein the article is moved in a conveying direction. An article detection unit that is longer than the ground contact length in the transport direction, is disposed on the transport path, and detects the article being transported, a weight detector that detects a weight of the article and outputs a weight signal; Weight determining means for determining a weight value of the article based on the signal, and at least a ground length of the article, the length of the weighing conveyor, a processing speed of the weighing device, and a weight value determining condition for determining the weight value by the weight determining means are stored. Storage means, and the contact length stored in the storage means,
Setting means for setting the weight value determination condition based on the weighing conveyor length and the processing speed. Here, the entire length of the article refers to the length from one end to the other end of the article in the transport direction, and the contact length refers to the length of the article in contact with the weighing conveyor in the transport direction. The processing speed includes the conveyor speed V or the capacity N. Further, the weight value determination condition is the weight value acquisition time ZT.
And filter characteristics.

According to the above construction, the weight determining means is based on the weight signal from the weight detector, and under the weight value determining conditions set in advance based on the ground length of the article, the length of the weighing conveyor, and the processing speed. When the total length (article length) is longer than the contact length of the article M, the weight of the article is determined in the weight value acquisition time (ZT) from the article detection to the acquisition of the article weight value. The weight signal is obtained based on the transport time (grounding length) in which the weighing conveyor is actually grounded. In this case, as in the conventional case, the transport time (article length) of the entire article including the portion where the article does not take weight because the article does not contact the weighing conveyor on the weighing conveyor.
If the length of the weighing conveyor is made constant as compared with obtaining the weight signal based on the above, the length of the weighing conveyor can be used effectively in time because the non-ground portion of the article is not included as the dead time for weighing. Therefore, assuming that the weight value take-in time and the production capacity are constant, the weighing conveyor length can be shortened by the amount not including the non-ground portion of the article as compared with the related art, and as a result,
The speed of the weighing conveyor that conveys articles can be reduced. Therefore, the vibration of the weighing conveyor is reduced, the posture of the article is stabilized, and the weighing accuracy is improved. In addition, the resistance to disturbance is improved by reducing the weight of the weighing conveyor.
Further, by lowering the speed of the weighing conveyor, not only the posture but also the transport pitch is stabilized, so that the post-process such as box packing is not disturbed and the working efficiency is improved. In addition, items that could not be set longer than the weighing conveyor length can be set based on the grounding length.

In the weighing device according to a second aspect of the present invention, the article detecting means is disposed at a position for detecting an end of the article in the transport direction when the article starts to contact the weighing conveyor. Here, the detection of the end includes both the detection of the front end and the detection of the rear end. Conventionally, the starting point of the weighing cycle ST is set at each time from the article detection (weight value take-in time ZT, re-detection prohibition time UT, two-seater detection time D
T, distribution time VT, etc.). This is because, conventionally, the article was assumed to be a cube, and the setting was made on the assumption that the time at which the article started to contact the weighing conveyor and the time at which the article detecting means detected the article were the same point. .
According to this configuration, the article can be detected when the article is actually grounded on the weighing conveyor. Therefore, without changing the setting method, only changing the position of the article detection means and grounding from the article length. Shorter ones can be weighed.

According to a third aspect of the present invention, in the weighing apparatus, the article detecting means is arranged at a position for detecting an end of the article in the conveying direction when the article starts to be carried into the weighing conveyor, and the setting means is provided. Is a weight determination condition including the time from when the article detection means detects the article to when the article starts to touch the weighing conveyor to the weight determination condition. According to the second aspect, there is no problem in weighing one kind of article, but it is necessary to change the position of the article detecting means every time when weighing a kind having a different article length or grounding length. In the case of the third aspect, since all can be handled by software processing, there is no need to change physical settings when weighing different types of articles.

In the weighing device according to a fourth aspect of the present invention, the article detecting means is disposed at a position for detecting an end of the article in the transport direction when the article starts to take off from the weighing conveyor. Starting from the start of the contact of the article with the weighing conveyor, the weight signal taking time ZT needs to be set because there is a time lag in determining the weight signal as the weight value. However, in the present invention, since the article detection signal is issued from the article detecting means at the time when the weight signal is to be changed to the weight value, the weight value can be determined immediately without providing the weight value taking-in time ZT.

In the weighing device according to a fifth aspect of the present invention, the article detecting means detects a front end of the article. In the case of front end detection, settings relating to weighing (weight value acquisition time ZT, re-detection inhibition time UT, two-seater detection time DT, distribution time V
T) can be set starting from the time at which the front end of the article is detected, thus simplifying the setting. In contrast, in the case of the rear end detection, the re-detection inhibition time UT must monitor the time from the front end to the rear end of the article, so that at least two references are required. In addition, in the case of detecting the trailing end, the two-seater detection time DT also detects the two-seater when the trailing end of the next article is detected. Since the distributing device must be arranged so that the existing article is on the distributing device, the disposition becomes very troublesome.

According to a sixth aspect of the present invention, in the weighing device according to the sixth aspect, the storage means stores the two-seater detection time when the next article is detected by the article detection means before the end of the weighing cycle of one article. And the length of the article in the transport direction of the article are stored, and the setting means sets the two-seater detection time based on the longer of the article length and the weighing conveyor length stored in the storage means. Setting means. Normal,
The two-seater detection (detecting the state in which the next article rides on the weighing conveyor while the weighing of one cycle is not completed) is set to the time obtained by dividing the weighing conveyor length by the weighing conveyor speed. In this way, two-seater riding can be detected and correct weighing can be performed. However, if the length of the article is longer than the length of the weighing conveyor, it is always detected that two articles are loaded and a warning is issued, so that normal weighing cannot be performed. Therefore, in this case, weighing can be performed without any problem if the time obtained by dividing the length of the weighed object by the weighing conveyor speed is used as the two-seater detection time. However, if this setting is maintained this time, the original two-carriage (the state in which the next article rides on the weighing conveyor while the weighing of one cycle is not completed) cannot be detected. The sixth aspect of the present invention enables a normal weighing operation while normally performing the two-seater detection.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a weighing device according to a first embodiment of the present invention. The weighing device measures the weight of an article while the article is being conveyed by a conveyor.
And a distribution conveyor 7. A photoelectric sensor 18 (article detecting means) is provided near the front end of the weighing conveyor 1.
Are arranged to detect that the article M is carried into the weighing conveyor 1 from the intake conveyor 6.
The take-in conveyor 6, the weighing conveyor 1 and the distribution conveyor 7 are each composed of a drive roller, a driven roller, and an endless belt suspended between the rollers, and are each driven in the same direction by a drive source (not shown). Is done. Articles conveyed from the take-in conveyor 6 in such a configuration are weighed by the weighing conveyor 1, and are sorted according to the weighing result.
The product is classified into defective weight products and positive weight products.

A load cell 5 (weight detector) is connected to the weighing conveyor 1, detects the weight of the article M to be conveyed by the weighing conveyor 1, and electrically converts the weight to output as a weight signal. An amplifier 8 is connected to the load cell 5 to amplify the weight signal. An A / D converter 9 is connected to the amplifier 8 and converts an analog output of the weight signal from the amplifier 8 into a digital signal. A DSP (digital signal processor) 10 is connected to the A / D converter 9 and processes the weight signal converted into the digital signal. The DSP 10 is configured as a low-pass filter, and filters the digitized weight signal. Note that the DSP 10 is set to various filter characteristics such as a low-pass filter of FIR type or a filter having a different cutoff frequency set in the storage unit 12 described later.

A control unit (CPU) 20 is provided in the weighing device.
Is provided. The control unit 20 includes a weight determining unit 14 for determining a weight value based on the weight signal filtered from the DSP 10 and a determining unit for determining the weight value from the weight determining unit 14 as a positive weight, a light weight or an overweight. 15, storage means 12 storing various weight value determination conditions (weighing conditions), setting means 16 for calculating and setting the weighing conditions stored in the storage means 12, and input means 17. Note that the control unit 20 is provided with the weight calculating means 1.
4 and the calculation and control of the setting means 16, the control and readout of the storage of the storage means 12, and the control of input and output inside and outside the control unit.

The weight determining means 14 determines the weight value of the filtered weight signal from the DSP 10 in accordance with the weighing conditions stored in the storage means 12. The storage means 12 also includes a ground contact length K1, a weighing conveyor length L, a weighing conveyor speed V, and a weight value determining condition, which are the lengths of the articles M to be weighed in the transport direction, and a sorting condition in the sorting conveyor 7 described later. Is stored for each type of article to be weighed. The setting means 16 calculates a weight value determination condition based on the ground contact length K1, the weighing conveyor length L, and the weighing conveyor speed V input from the input means 17 connected to the control section 20. The weight value determination condition (weighing condition) refers to a weight value acquisition time ZT, a filter characteristic, and the like.

The control unit 20 is connected to a distribution control unit 19 for controlling the distribution conveyor 7, and the determination unit 1
The defective articles determined to be light or excessive in step 5 are sorted according to the sorting conditions stored in the storage means 12.
The distribution conveyor 7 has a distribution unit (not shown), for example, an arm-type distribution unit. Note that the distribution conditions include the type of the distribution unit (arm type, drop type, air type, etc.) and the operation of the distribution unit when the product M is defective after the photoelectric sensor 18 detects the product M. In addition to the distribution time VT which is the time until the start, there is a distribution ON time and the like.

As shown in FIG. 2, the article M to be weighed is, for example, a grounding section Mt where the article M is in contact with the weighing conveyor 1, such as a packaged product wrapped with a film.
Each end has a weighing conveyor 1 and a seal portion (ear) Ms that is not grounded. The contact length of the contact portion Mt in the transport direction is K1, and the length of the seal portion Ms is K2. Article M
The total length (article length) K is longer than the contact length K1 of the contact portion Mt in the transport direction, and the total length (measurement conveyor length) L of the weighing conveyor 1 is larger than the contact length K1. That is, the product length K> the weighing conveyor length L> the contact length K1.

The weighing conveyor 1 is composed of, for example, two belts running in parallel at a distance from each other. The photoelectric sensor 18 disposed near the front end of the weighing conveyor 1 includes a photoelectric sensor main body 18a and a mirror 18b that reflects a light beam from the photoelectric sensor main body 18a. Above the photoelectric sensor body 18a
However, the mirrors 18b are respectively arranged below. The photoelectric sensor 18 detects the position of the article M downstream of the entrance end of the weighing conveyor 1, that is, when the grounded portion Mt of the article M is grounded to the weighing conveyor 1, the sealing portion Ms at the tip of the article M It is arranged at the position where is detected.

Next, the operation of the weighing device having the above configuration will be described with reference to the time chart of FIG. First, based on the ground length K1 and the article length K of the article M of FIG. 2 stored in the storage unit 12 of FIG. 1 in advance, the photoelectric sensor 18 reads the article conveyed from the take-in conveyor 6 as shown in FIG. When the grounding portion Mt of M comes into contact with the weighing conveyor 1 and the load of the article M actually starts to be applied, it is arranged at a position P1 (time point t1) indicated by a solid line for detecting the sealing portion Ms at the tip of the article M. . Then, the grounding section Mt of the article M is connected to the weighing conveyor 1.
And the weight signal increases as the contact portion of the contact portion Mt gradually increases. Then, at the position P2 (time point t2) indicated by the one-dot chain line, the entire ground contact portion Mt of the article M completely moves onto the weighing conveyor 1. This time is the transfer time RT.

Then, from this time point t2, the state in which the entire article M is on the weighing conveyor 1 is completed (a part of the article M is transferred to the downstream carry-out conveyor 7). ) Is the weighing stabilization time WT. The weighing stabilization time WT corresponds to a value obtained by adding the sampling time FST to the filter time FT. The value obtained by adding the transfer time RT is the weight value acquisition time ZT.
Becomes The article M reaches P3 (t3) after the elapse of the set filter time FT and the elapse of the sampling time FST. This position is a position where the front end of the article M has reached the end of the weighing conveyor 1. The filter time FT is a time constant (delay time) determined by the type of the filter stored in the storage unit 12. The sampling time FST is a time corresponding to three times of the weight signal output from the set filter. This is because the DSP 10 performs sampling at a predetermined sampling cycle, so that the weight signal is not output continuously, but the weight signal is output intermittently corresponding to the sampling cycle. If the weight signal is stable within a predetermined range (for example, a width of ± 0.1 g) within the sampling time FST, it is determined that the weight signal is stable, and the weight signal is averaged over three times. If it is not within the predetermined range, it is determined as unstable by the determination means 15 and is eliminated by the downstream sorting conveyor 7. This time is the sampling time FST
Is so short that it can be considered a constant.

Thereafter, the article M is transferred to the sorting conveyor 7, and the article M determined to be defective is removed at P4 (t4). This time is the distribution time VT. Also,
The time equal to the transfer time RT is the re-detection inhibition time UT. The re-detection prohibition time UT is a time during which the detection of the article M is ignored within a predetermined time after the photoelectric sensor 18 detects the front end of the article M. This is the article M is a package,
When the packaging material is partially transparent, it is recognized that the article M has passed on the way despite the passing of the article M, and then the article M starts to pass at the opaque packaging material. This prevents erroneous detection of detecting that the

Further, the two-seater detection time DT indicates that the weighing of the first article M is completed when the photoelectric sensor 18 detects the article M again within a predetermined time after detecting the first article M. Despite the absence, the next article M will be on the weighing conveyor 1, and as a result, the first article M will be weighed while the two articles M are on the weighing conveyor 1, resulting in erroneous weighing. It is time to detect that

As described above, the present weighing device includes the load cell 5
And the weight value determination condition (weighing condition) set by the ground length K1, the weighing conveyor length L, and the processing speed of the article M stored in the storage means 12 in advance based on the weight signal from
The weight value of the article M is determined by the weight determining means 14. Therefore, when the article length K is longer than the contact length K1 of the article M, the weight value acquisition time ZT from the article detection to the acquisition of the weight value of the article M is based on the contact length K1, that is, FIG. As shown in FIG.
Is grounded to the weighing conveyor 1, and when the load of the article M actually starts to be applied, the sealing section Ms at the tip of the article M is detected. The weight signal is obtained based on the transfer time (contact length K1) during which the touch panel is touched. On the other hand, the conventional weighing device is based on the article length K, that is, when the grounding portion Mt of the article M is not grounded to the weighing conveyor 1 by the photoelectric sensor 18 as shown in FIG. Detecting the sealing section Ms at the tip of the article M, the grounding section Mt of the article M is not in contact with the weighing conveyor 1, and the transport time of the entire article including the sealing section Ms where the article is not weighted (article length K) The weight signal is obtained on the basis of.

As described above, the present weighing device is provided with the weighing conveyor 1
Assuming that the length is constant, the weighing conveyor length L can be used more effectively as compared to the conventional weighing device because the non-ground portion Ms of the article is not included as the weighing dead time (K2 / V). Therefore, assuming that the weight value take-in time ZT and the production capacity N are constant, the weighing conveyor length L can be reduced by the amount not including the non-ground portion Ms of the article M as compared with the related art, and as a result, the article M is conveyed. The metering conveyor speed V can be reduced. For this reason, the vibration of the weighing conveyor 1 is reduced, the weight value take-in time ZT is also shortened, and the posture of the article M is stabilized, and the weighing accuracy is improved. In addition, the resistance to external disturbances is improved by reducing the weight of the weighing conveyor 1. Furthermore, by lowering the weighing conveyor speed V, not only the posture but also the transport pitch is stabilized, so that the post-process such as box packing is not disturbed, and the working efficiency is improved. In addition, although it has been impossible to set an article longer than the weighing conveyor length L in the past, it can be set based on the grounding length K1.

In FIG. 3, the speed V of the weighing conveyor 1 is V = K × N. The measuring cycle ST is K / V
(1 / N), which corresponds to the article length K. Conventionally, the re-detection prohibition time UT cannot be set if K / V is longer than L / V because the article length K is conventionally shorter than the weighing conveyor length L.

In this weighing device, since the article length K is longer than the weighing conveyor length L, the photoelectric sensor 18 may detect the article M being weighed at the position P3 (time point t3). When the two-seater detection time DT is calculated using the weighing conveyor length L as one cycle of weighing, the photoelectric sensor 18 detects the article M even after the time exceeds this time. You. Therefore, the weighing cycle ST is defined as the article length K, and
The individual riding detection time DT is calculated.

In this embodiment, the case where the article length K is longer than the weighing conveyor length L is applied.
Is shorter than the weighing conveyor length L, that is, when the weighing conveyor length L> article length K> ground length K1. In this case, one cycle of weighing is defined as the weighing conveyor length L as in the related art. Let L / V be the two-seater detection time DT.

That is, the setting means 16 sets the two-seater detection time DT based on the long product length K and the weighing conveyor length L stored in the storage means 12. Usually, the two-seater detection time DT is set to a time obtained by dividing the weighing conveyor length L by the weighing conveyor speed V. In this way, two-seater riding can be detected and correct weighing can be performed. However, when the article length K is longer than the weighing conveyor length L, it is always detected that two pieces are loaded and a warning is issued, so that normal weighing cannot be performed. Therefore, in this case, if the time obtained by dividing the article length K by the weighing conveyor speed V is used as the two-seater detection time DT, weighing can be performed without any problem. However, if the setting is maintained this time, when K <L, two-seater cannot be detected. According to the length of the article length K and the length of the weighing conveyor L, 2
By setting the individual riding detection time DT based on the long one of the article length K and the weighing conveyor length L, a normal weighing operation can be performed while normally performing the double riding detection.

Next, a second embodiment will be described.
The weighing device according to the second embodiment is different from the weighing device according to the first embodiment, as shown in FIG.
When the article M starts to be carried in from the weighing conveyor 1, the article M is arranged at a position for detecting the front end in the transport direction of the article M. The setting means 16 in FIG. Is detected and the time from when the article M starts to touch the weighing conveyor 1 is set as the weight determination condition. Other configurations are the same as those in FIG.

That is, in the second embodiment, since the photoelectric sensor 18 is attached to the front end of the weighing conveyor 1,
By adding a delay time (K2 / V) to the output from the photoelectric sensor 18, the weight value capturing time ZT,
The time of K2 / V is added to the distribution time VT.

As described above, the weighing device of the second embodiment is
As in the first embodiment, during the weight value capturing time ZT from the article detection to the capturing of the weight value of the article, the transport time during which the article is actually in contact with the weighing conveyor (contact length K1)
Based on the weight signal. Therefore, the length of the weighing conveyor can be shortened as much as the time required for taking in the weight value can be made longer than before, and as a result, the speed of the weighing conveyor for transporting the articles can be reduced, and the same effect as in the first embodiment can be obtained. In the first embodiment, there is no problem in weighing one type of article M. However, each time an object length K or a ground contact length K1 is weighed, a photoelectric sensor 18 is required.
Needs to be changed. In the second embodiment, since all can be handled by software processing, there is no need to change physical settings when weighing different types of articles M. Further, in the case of front end detection, all the settings related to weighing (weight value take-in time ZT, re-detection prohibition time UT, two-seater detection time DT, distribution time VT, etc.) start from the time when the front end of the article M is detected. Setting can be simplified. In contrast, in the case of the rear end detection, the re-detection inhibition time UT must monitor the time from the front end to the rear end of the article, so that at least two references are required. Also,
In the case of detecting the rear end of the two-seat detection time DT, the two-seater is detected when the rear end of the next article M is detected. Since the sorting unit must be arranged so that the article M is on the sorting conveyor 7, the arrangement becomes very troublesome.

Although the front end is detected in the second embodiment, the rear end can be detected. In this case, the photoelectric sensor 18 may be mounted at an appropriate position upstream of the front end detection. However, the re-detection detection time UT and the two-seater detection time DT also need to detect the front end.

Next, a third embodiment will be described.
In the third embodiment, unlike the second embodiment, the filter time FT is calculated to determine the filter characteristic of the DSP 10 in FIG. Capture. This is because the DSP 10 constantly outputs a weight signal in a constant cycle. Other configurations are the same as in the second embodiment.

In each of the above embodiments, the load cell is used for the weight detector, but a tuning fork type or an operation transformer may be used. Further, the weighing conveyor speed V is input by the input means 17, but the weighing conveyor speed V may be calculated by inputting the production capacity N. Further, the transfer time RT, the filter time FT, and the sampling time FST may be stored in the storage unit 12 without storing the weight value capturing time ZT.

In each of the above embodiments, an article having a longer overall length than the ground contact length is applied to an article wrapped with a film. However, the present invention is not limited to this. May be applied to other articles.

[0045]

As described above, according to the configuration of the present invention, the length of the weighing conveyor can be shortened by the length of the time required for taking in the weight value as compared with the prior art. Can be slowed down. For this reason, the posture of the article is also stabilized, and the weighing accuracy is improved. Further, by lowering the speed of the weighing conveyor, not only the attitude but also the transport pitch is stabilized, so that the post-process such as box packing is not disturbed and the working efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a weighing device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an example of an article to be weighed.

FIG. 3 is a time chart illustrating an operation of the weighing device of FIG. 1;

FIG. 4 is a configuration diagram showing an operation of the weighing device of FIG. 1;

FIG. 5 is a configuration diagram illustrating a weighing device according to a second embodiment of the present invention.

FIG. 6 is a time chart illustrating the operation of a conventional weighing device.

[Explanation of symbols]

1: weighing conveyor, 5: weight detector (load cell), 1
2 ... storage means, 14 ... weight determination means, 15 ... determination means,
16 setting means, 18 article detection means (photoelectric sensor),
K: full length of the article (article length), K1: ground contact length of the article, L ...
The total length of the weighing conveyor (weighing conveyor length), M: articles.

Continued on the front page (72) Inventor Akira Ishino One at 959 Shimogaku, Ritto-cho, Kurita-gun, Shiga Prefecture Inside the Ishida Shiga Plant (72) Inventor Kenji Nakado One-959th, Shimogaoka, Ritsuto-cho, Kurita-gun, Shiga Prefecture Ishida Shiga Office

Claims (6)

[Claims] 1. A weighing apparatus for continuously measuring the weight of an article while the article is being conveyed by a weighing conveyor, wherein the article has a total length in the conveying direction longer than a grounding length in the conveying direction, and is arranged on the conveying path. Article detecting means for detecting the article being conveyed, a weight detector for detecting a weight of the article and outputting a weight signal, and a weight determining means for determining a weight value of the article based on the weight signal. Storage means for storing a ground length of the article, the weighing conveyor length, a processing speed of the weighing device and a weight value determination condition for determining the weight value by the weight determination means, and the ground length stored in the storage means; Setting means for setting the weight value determination condition based on the weighing conveyor length and the processing speed. 2. The weighing device according to claim 1, wherein the article detecting means is arranged at a position for detecting an end of the article in a conveying direction when the article starts to contact the weighing conveyor. 3. The article detecting device according to claim 1, wherein the article detecting means is arranged at a position for detecting an end of the article in a conveying direction when the article starts to be carried into the weighing conveyor, and wherein the setting means determines the weight. The weighing device further includes a condition for determining a weight including a time from when the article detecting means detects the article to when the article starts to contact the weighing conveyor. 4. The weighing device according to claim 1, wherein the article detecting means is arranged at a position for detecting an end of the article in a conveying direction when the article starts to take off from the weighing conveyor. 5. The weighing device according to claim 2, wherein the article detecting means detects a front end of the article. 6. The two-seater detection according to claim 1, wherein the storage means stores an abnormality when the next article is detected by the article detection means before the end of the weighing cycle of one article. The setting unit sets the two-seater detection time based on the longer of the article length and the weighing conveyor length stored in the storage unit. A weighing device comprising: a setting unit that performs setting.