JP5308887B2 - Weighing device and combination weigher equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a weighing device and a combination balance with the same, capable of rapidly and reliably detecting a poor discharge of a weighing hopper without making its weighing cycle long. <P>SOLUTION: A memory 32 previously stores an output (null weight change output Wv) of a weight sensor 2 during a period (weighing hopper weight change detection period T) ranging from a timing at which a gate 11 in its closed state is brought into its opened state in the weighing hopper 1 having no weighing subject to be thrown therein, to a timing at which a new weighing subject arrives after bringing the gate into its closed state again. A control unit 31 functioning as a discharge decision means 31a detects an output (discharge weight change output Wx) of the weight sensor 2 during the weighing hopper weight change detection period T in the weighing hopper 1 having a thrown weighing subject, and calculates a difference between the null weight change output Wv and the discharge weight change output Wx. An operation setting display device 8 being a signifying means signifies such the state that the poor discharge of the weighing subject arises, when the difference between the null weight change output Wv and the discharge weight change output Wx is equal to or more than a prescribed value. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a weighing device and a combination weigher including the weighing device, and more particularly to a weighing device that measures an object to be weighed temporarily held in a weighing hopper with a weight sensor and a combination weigher including the weighing device.

  In a weighing device that is provided on a combination weigher and has a configuration that temporarily holds an object to be weighed on a weighing hopper, the weight of the weighing hopper is set to the weight of a load cell or the like while the object to be weighed is held on the weighing hopper. Weighing with a sensor, and subtracting the weight of the weighing hopper, it is detected as the weight of the object to be weighed. Therefore, if the weighing object weighed by the weighing hopper is not successfully discharged, an error will occur between the weighing value and the discharge amount. Therefore, it is necessary to check whether the weighing object is completely discharged from the weighing hopper. It is necessary to quickly and reliably detect the discharge failure.

  As a configuration for detecting the discharge failure of the weighing hopper, for example, in Patent Document 1, the output values of the weight detectors are detected before and after the object to be weighed is put into the weighing section, and they are within the set normal range. The structure which determines whether it is for every measurement section is disclosed. Further, in Patent Document 2, after weighing a product with a weighing hopper, the weight of the weighing hopper is re-detected after a certain time has elapsed, and the re-detected weight of the weighing hopper and the weighing hopper are discharged. A configuration is disclosed in which whether or not there is a discharge abnormality of the weighing hopper is determined by comparing with a predetermined weight that can be considered.

Japanese Utility Model Publication No. 55-119933 JP 2004-125694 A

  However, in the configurations described in Patent Documents 1 and 2, after detecting the weight of the weighing hopper after the object to be weighed is input, the gate of the weighing hopper is opened and before the next object to be weighed is supplied. Since it is necessary to detect the weight of the weighing hopper in an empty state, it is necessary to delay the timing of supplying the weighing object for the next time to the weighing hopper, and it is not possible to shorten one weighing cycle. there were.

  The present invention has been made to solve the above-described problems, and a weighing device capable of quickly and reliably detecting a discharge failure of a weighing hopper without lengthening a weighing cycle, and a combination weigher including the weighing device. The purpose is to provide.

  A weighing device according to the present invention has a gate that can be opened and closed, a weighing hopper that discharges a temporarily held object by opening the gate, and an object to be weighed held by the weighing hopper. In the weighing hopper including the weight sensor for detecting the weight of the weighing hopper, the control means for opening and closing the gate, and the weighing hopper in a state where the object to be weighed is not charged, the gate is changed from the closed state to the closed state again. Storage means for storing in advance the output of the weight sensor (hereinafter referred to as the empty weight change output) during the period until the new object reaches (hereinafter referred to as the weighing hopper weight change detection period) In the weighed hopper in the measured state, the weight sensor output during the weighing hopper weight change detection period (hereinafter referred to as discharge weight change output) is detected and stored in the storage means. And a, a discharge failure detection means for detecting the discharge failure has occurred in the object to be weighed on the basis of the difference between the air weight change output and the discharge weight change output which is.

  The “weighing hopper” in the claims and the specification means a hopper mechanism that can weigh the weighing hopper including an object to be weighed by a weight sensor.

  According to the weighing device having the above-described configuration, when a discharge failure of the weighing object occurs, weighing in a state in which the weight change during the gate opening / closing operation of the weighing hopper to which the weighing object is supplied does not hold the weighing object. Since it is detected that the weight change is different from the gate opening / closing operation of the hopper, it is possible to quickly and reliably detect the discharge failure of the weighing hopper without lengthening the weighing cycle.

  The discharge failure detection means detects the discharge weight change output in a weighing hopper in a state where an object to be weighed is inserted, and calculates a difference between the empty weight change output stored in the storage means and the discharge weight change output. And a notifying means for notifying that a discharge failure of the weighing object has occurred when the difference between the empty weight change output and the discharge weight change output is equal to or greater than a predetermined value. When the difference between the empty weight change output and the discharge weight change output is calculated and it is determined that the difference between the empty weight change output and the discharge weight change output is equal to or greater than the predetermined value, a discharge failure of the weighing object has occurred. Therefore, it is possible to prevent erroneous discharge from being detected erroneously.

  The discharge determination means may compare the empty weight change output and the discharge weight change output in the whole period of the weighing hopper weight change detection period, or may compare in a partial period. Further, the weight values at one or more predetermined times within the weighing hopper weight change detection period may be compared.

  The empty weight change output and the discharge weight change output are digital outputs obtained by digitizing the output from the weight sensor, and the discharge determination unit is configured to perform the predetermined sampling period in the weighing hopper weight change detection period. A difference between the sums of the weight values sampled from the empty weight change output and the discharged weight change output may be calculated. As a result, the empty data change output and the discharge weight change output, which are digital data, are sampled and added together in a predetermined sampling period, and are compared with each other, so there is almost no additional special control mechanism or control program. , Can do quick calculations.

  The discharge determination means includes the empty weight change output and the discharge weight change output after the comparison start with reference to the time when the gate of the weighing hopper is opened in the weighing hopper weight change detection period. May be configured to calculate the difference between When the weighing hopper gate is opened, all the objects to be weighed held by the weighing hopper should be separated from the weighing hopper unless there is a defective discharge. Therefore, by setting the comparison start time based on the time when the gate of the weighing hopper is in the open state, it is possible to more closely match the waveform change at the normal time of the empty weight change output and the discharge weight change output in the comparison range. Therefore, the discharge failure of the weighing hopper can be detected more reliably.

  The discharge determination means includes the empty weight change output and the discharge weight change output before the end of the comparison with respect to a time when the gate of the weighing hopper is in a closed state in the weighing hopper weight change detection period. May be configured to calculate the difference between When a new object is supplied to the weighing hopper before the weighing hopper is closed, the discharge weight change output before the measurement object is supplied to the weighing hopper is compared with the empty weight change output. It is preferable. Therefore, by setting the end of comparison based on the time when the gate of the weighing hopper is closed, in order to supply a new object to the weighing hopper that has detected the output change in discharged weight, While supplying the objects to be weighed quickly, it is possible to more reliably detect the discharge failure of the weighing hopper by making the waveform changes in the normal state of the empty weight change output and the discharge weight change output in the comparison range more coincident.

  A supply hopper disposed on the upstream side of the weighing hopper and supplying an object to be weighed to the weighing hopper using a gate that can be opened and closed; and the discharge determining means includes the weighing hopper weight change detection period. The difference between the empty weight change output and the discharge weight change output before the end of comparison based on the time when the gate of the supply hopper corresponding to the weighing hopper that has detected the discharge weight change output starts to open from the closed state. May be configured to calculate. When the weighing object is newly supplied from the supply hopper to the weighing hopper before the weighing hopper is closed, the discharge weight change output before the weighing object is supplied to the weighing hopper is output as the empty weight change output. It is preferable to compare with. Therefore, by setting the comparison end time based on the time when the gate of the supply hopper corresponding to the weighing hopper that has detected the discharge weight change output starts to open from the closed state, the object to be weighed can be quickly supplied to the weighing hopper. On the other hand, it is possible to more reliably detect the discharge failure of the weighing hopper by making the waveform changes in the normal state of the empty weight change output and the discharge weight change output in the comparison range more coincident.

  The combination weigher according to the present invention includes the weighing device having the above configuration. That is, the combination weigher according to the present invention includes a weighing device that can quickly and reliably detect discharge failure of the weighing hopper without lengthening the weighing cycle, so that the combination calculation processing can be performed more quickly and accurately. It can be carried out.

  The present invention is configured as described above, and has an effect that the discharge failure of the weighing hopper can be detected promptly and reliably without deteriorating the weighing accuracy and without lengthening the weighing cycle.

It is sectional drawing which shows the schematic structure of the combination scale to which the weighing | measuring device which concerns on one Embodiment of this invention was applied in the cross section seen from the side. It is a block diagram which shows schematic structure of the control system of the combination weigher shown in FIG. It is a time chart regarding the control operation | movement of each structure of the combination weigher shown in FIG. It is a flowchart which shows the control operation of the combination weigher shown in FIG. It is a flowchart which shows the control operation | movement of the discharge | emission determination process in the combination scale shown in FIG. It is a graph which shows the example of the empty weight change output of the weighing hopper of the combination weigher shown in FIG. 1, and the discharge weight change output in the normal time. It is a graph which shows the example of the empty weight change output of the weighing hopper of the combination weigher shown in FIG. 1, and the discharge weight change output at the time of discharge failure.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description thereof is omitted. In the following embodiments, a description will be given of a fully automatic combination weigher in which an object to be weighed is automatically supplied, and an object to be weighed selected as a discharge combination is automatically discharged after combination calculation.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a combination weigher to which a weighing apparatus according to an embodiment of the present invention is applied, as viewed from the side. The combination weigher according to the present embodiment has a plurality of (for example, 14) weighing hoppers 1 as shown in FIG. The plurality of weighing hoppers 1 are arranged, for example, in a circular shape (on the circumference), but may be arranged in other modes (an elliptical shape, a linear shape, etc.). The plurality of weighing hoppers 1 temporarily hold the objects to be weighed supplied from above, and discharge the objects to be weighed downward by opening the openable gate 11 provided in the lower part. Each of the plurality of weighing hoppers 1 is supported by a weight sensor 2 that detects the weight of the weighing hopper 1. For the weight sensor 2, for example, a load cell is used. The weight sensor 2 is connected to the control device 3, and the weight measured by the weight sensor 2 is transmitted to the control device 3. Here, since the weight of the weighing hopper 1 is known, the control device 3 subtracts the weight of the weighing hopper 1 from the weight detected by the weight sensor 2 to hold the weighing object held by the weighing hopper 1. Weigh the weight. Thus, the weight sensor 2 and the control device 3 in the present embodiment constitute a weighing device.

  Note that the weighing hopper in this embodiment means a hopper mechanism that can weigh the weighing hopper including the object to be weighed by the weight sensor. Therefore, the present invention can be applied to a hopper mechanism that is not used as a weighing hopper for detecting the weight of an object to be weighed for combination calculation as long as a weight sensor is provided. That is, for example, in a memory hopper arranged downstream of the weighing hopper, the weight of the object to be weighed is weighed by the corresponding weighing hopper and stored in association with the control device 3. A weight sensor for detecting defective discharge may be provided. In this case, it is possible to use a sensor having a lower accuracy than the weight sensor used for the combination calculation as the weight sensor for detecting defective discharge. This is because the accuracy (for example, ± 5 g) required for discharge defect detection may be lower than the accuracy (for example, ± 0.1 g) required for the combination calculation.

  A supply hopper 4 is provided upstream of the weighing hopper 1. In the present embodiment, a plurality of supply hoppers 4 are respectively disposed above the plurality of weighing hoppers 1. The supply hopper 4 temporarily holds an object to be weighed supplied from above, and discharges the object to be weighed downward by opening a gate 41 that can be opened and closed provided below the object.

  A supply unit 5 is provided upstream of the supply hopper 4. The supply unit 5 feeds the object to be weighed supplied from the external supply device 10 into the center of the combination weigher radially by vibration and the object to be weighed sent from the main feeder 51 by vibration. A plurality of rectilinear feeders 52. The main feeder 51 includes a cone-shaped or disk-shaped top cone 511 disposed below the supply port of the external supply device 10 and a vibrator 512 that vibrates the top cone 511 vertically or horizontally. doing. The plurality of rectilinear feeders 52 include a plurality of rectilinear feeder pans 521 disposed around the top cone 511 and a plurality of vibrators 522 that vibrate the plurality of rectilinear feeder pans 521 obliquely upward in the tip direction. And have. The plurality of rectilinear feeders 52 are provided corresponding to the supply hoppers 4, and the objects to be weighed fed by the plurality of rectilinear feeders 52 are supplied to the corresponding supply hoppers 4. As described above, the combination weigher of the present embodiment is provided with a plurality of sets of head portions each including the linear feeder 52, the supply hopper 4, the weighing hopper 1, and the weight sensor 2. For example, the vibrators 512 and 522 vibrate the top cone 511 or the rectilinear feeder pan 521 by continuously switching the electromagnet ON / OFF.

  Downstream of the weighing hopper 1, there is disposed a collective discharge unit 6 that collects the objects to be weighed held in one or more weighing hoppers selected for the discharge combination described later and discharges them outside the apparatus. The collective discharge unit 6 includes an inverted conical collective chute 61 and a discharge chute 62 disposed below the collective chute 61. The objects to be weighed discharged from the one or more weighing hoppers 1 through the gate 11 are gathered by sliding down the collecting chute 61, and the packaging machine outside the machine is passed through the discharging chute 62 provided below the collecting chute 61 (see FIG. (Not shown). The collective discharge unit 6 may have a configuration in which a hopper is disposed at the position of the discharge chute 62.

  In the present embodiment, the control device 3 includes one or more combinations of the weights of the objects to be weighed by the weighing device including the weight sensor 2 and the control device 3 among the weighing hoppers 1 holding the objects to be weighed. A combination calculation for selecting a combination of the weighing hoppers 1 whose weight is within a predetermined range including the target combination weight as a combination of the weighing hoppers 1 to discharge the objects to be weighed (hereinafter referred to as discharge combinations). It is configured.

  The control device 3 further functions as control means for performing opening / closing control of the gate 11 of each weighing hopper 1. Opening / closing control of the gate 41 of each supply hopper 4 and the gate 11 of each weighing hopper 1, supply control of the supply unit 5, and supply control of the external supply device 10 are performed. Further, the combination weigher of the present embodiment includes an operation setting display device 8 that can perform various operation settings and display the settings. The operation setting display device 8 is also controlled by the control device 3.

  The control system in the combination weigher of this embodiment will be described in more detail. FIG. 2 is a block diagram showing a schematic configuration of a control system of the combination weigher shown in FIG.

  For example, the control device 3 includes a control board 30 having a control unit 31 and a storage unit 32. The control device 3 includes, for example, a microcomputer, and the control unit 31 uses, for example, a CPU of the microcomputer. For example, an internal memory of the microcomputer is used for the storage unit 32. The control unit 31 and the storage unit 32 are connected to each other. The storage unit 32 stores a control program. Further, the storage unit 32 functions as a storage unit that stores various data. In addition, the control unit 31 reads out and executes the control program stored in the storage unit 32 to perform processing such as calculation and control. Specifically, the control unit 31 receives signals from the operation setting display device 8 and the plurality of weight sensors 2, performs processing including discharge determination and combination calculation based on these signals, and stores these processing results. 32. Further, based on these signals, the opening / closing control of the gates 11 of the plurality of weighing hoppers 1 and the gates 41 of the plurality of supply hoppers 4, the supply control of the main feeder 51, the plurality of linear feeders 52 and the external supply device 10, and Then, notification control for transmitting a control signal to the operation setting display device 8 for notification is performed. In other words, the control unit 31 functions as the discharge determination unit 31a and the control unit 31b, and the operation setting display device 8 functions as a notification unit. Therefore, in the present embodiment, the control unit 31 that functions as the discharge determination unit 31a and the operation setting display device 8 that functions as the notification unit function as the discharge failure detection unit.

  In the present embodiment, the control device 3 is configured by one control board, but the present invention is not limited to this as long as the same control can be performed. That is, for example, a plurality of control boards may be provided according to various controls, and the control device 3 may be configured by the plurality of control boards. The control device 3 is not necessarily provided in the combination weigher. For example, the control device 3 may be controlled by the external control device 3 by connecting a personal computer or the like as the external control device 3.

  Further, the combination weigher of the present embodiment includes a supply level detector 9 that detects the supply status of an object to be weighed from the external supply device 10 to the top cone 511 of the main feeder 51, as shown in FIGS. I have. The supply level detector 9 and the external supply device 10 are respectively connected to the control device 3, and the control device 3 detects the object to be weighed according to the supply status of the object to be weighed detected by the supply level detector 9. The external supply device 10 is controlled so as to change the supply amount. The external supply device 10 may be, for example, a belt conveyor or a device that vibrates a trough-shaped supply pan.

  In this embodiment, in the weighing hopper 1 in a state in which the object to be weighed is not charged, the gate 11 is changed from the closed state to the closed state again until the new object to be weighed is reached. The output of the weight sensor 2 during the period (the weighing hopper weight change detection period T) is stored in advance as the empty weight change output Wv. Then, the control unit 31 functions as a discharge failure detection means, and detects the output (discharge weight change output Wx) of the weight sensor 2 in the weighing hopper weight change detection period T in the weighing hopper 1 in a state where an object to be weighed is inserted. Then, based on the difference between the discharge weight change output Wx and the empty weight change output Wv stored in the storage unit 32, it is detected that a discharge failure of the weighing object has occurred. More specifically, the control unit 31 functions as the discharge determination unit 31a, and outputs the output of the weight sensor 2 (discharge weight change output) in the weighing hopper weight change detection period T in the weighing hopper 1 in a state where an object to be weighed is inserted. Wx) is detected, the difference between the empty weight change output Wv and the discharge weight change output Wx stored in the storage unit 32 is calculated, and the difference between the empty weight change output Wv and the discharge weight change output Wx is equal to or greater than a predetermined value. It is determined whether or not there is.

  Below, operation | movement of the control apparatus 3 is demonstrated in order. FIG. 3 is a time chart regarding the control operation of each component of the combination weigher shown in FIG. FIG. 4 is a flowchart showing the control operation of the combination weigher shown in FIG. As shown in FIG. 3 and FIG. 4, when a discharge request signal is output from an external device such as a packaging machine with the object to be weighed held in the weighing hopper 1 (Yes in step SA1), and there is a discharge combination (Yes in step SA2), the control unit 31 starts opening / closing driving of the weighing hopper 1 selected for the discharge combination (step SA3). As shown in FIG. 3, when the gate 11 of the weighing hopper 1 starts to open from the closed state (time t1 in FIG. 3), the weighing hopper weight change detection period T starts. When there is no discharge combination (No in step SA2), the control unit 31 controls to supply the object to be weighed from the supply hopper 4 to the vacant hopper 1 (step SA12).

  The control unit 31 detects the output of the weight sensor 2 as the discharged weight change output Wx until the weighing hopper 1 selected as the discharge combination from the start of the weighing hopper weight change detection period T goes through the open state and then closes again. (Step SA4). The objects to be weighed discharged from the weighing hopper 1 are collected by the collective discharge unit 6 and discharged outside the apparatus if there is no discharge failure in the discharge determination process described later. Here, if there is no defective discharge, the object to be weighed held in the weighing hopper 1 is completely transferred to the weighing hopper 1 when the gate 11 of the weighing hopper 1 is opened (time t2 in FIG. 3). The weight detected by the corresponding weight sensor 2 should ideally be the weight of the weighing hopper 1 alone (the weight of the object to be weighed is 0). However, in actuality, the weighing hopper 1 is vibrated due to the opening / closing drive of the gate 11 and the weight detected by the weight sensor 2 does not become a constant value.

  Further, the control unit 31 starts opening the gate 41 of the corresponding supply hopper 4 from the closed state after a predetermined time (time t3 in FIG. 3) with reference to the time when the gate 11 of the weighing hopper 1 starts to close from the open state. Control is performed as follows (Yes in step SA5). The controller 31 detects the output of the weight sensor 2 as a weight value for the combination calculation from when the opening / closing drive of the supply hopper 4 is started. That is, the time when the gate 41 of the supply hopper 4 starts to open from the closed state (time t3) is the start time of the combination weighing period for the combination calculation. As described above, while both the weighing hopper 1 and the supply hopper 4 are in the open / close drive state, the output of the weight sensor 2 is detected as the discharge weight change output Wx and the weight value for combination calculation, respectively (step SA6).

  Thereafter, when the weighing hopper 1 is closed and a new object to be weighed arrives from the corresponding supply hopper 4 (Yes in step SA7), at this time (time t5 in FIG. 3), the weighing hopper weight change detection period T ends. The control unit 31 stores the output of the weight sensor 2 in the weighing hopper weight change detection period T in the storage unit 32 as the discharge weight change output Wx. And the control part 31 functions as the discharge determination means 31a, and performs the discharge determination process which compares the empty weight change output Wv memorize | stored in the memory | storage part 32, and the discharge weight change output Wx, and determines the presence or absence of discharge defect. (Step SA8). Details will be described later.

  If there is no discharge failure as a result of the discharge determination process, weight detection for combination calculation is continued (step SA9). After the predetermined combination weighing period ends (Yes in step SA10), the next discharge combination calculation process is performed (step SA11). Thereafter, a predetermined measurement cycle is repeated with steps SA1 to SA11 as one measurement cycle.

  Here, the discharge determination process will be described in detail. FIG. 5 is a flowchart showing the control operation of the discharge determination process in the combination weigher shown in FIG. As described above, the empty weight change output Wv and the discharge weight change output Wx are stored in the storage unit 32 before the start of the discharge determination process. The discharge weight change output Wx is stored in the same number as the number H selected for the discharge combination.

  Note that only one empty weight change output Wv may be stored, or one corresponding to each weighing hopper 1 may be stored in advance. However, the open / close mechanism of the gate 11 of the weighing hopper 1 may be hard or worn. Since the waveform of the empty weight change output Wv can change accordingly, it is preferable to store the empty weight change output Wv for each weighing hopper 1. Furthermore, considering that the weighing hopper 1 is replaced, it is possible to detect and store the empty weight change output Wv for each of the weighing hoppers 1 attached to the combination weigher at the start of operation of the combination weigher. preferable. Further, even during the operation of the combination weigher, the waveform of the empty weight change output Wv can change due to a small amount of debris of the object to be weighed in the weighing hopper 1, so that the gate 11 of the weighing hopper 1 is driven to open and close. The empty weight change output Wv is detected and stored for each of the weighing hoppers 1 for which the automatic zero adjustment has been performed even after the automatic zero adjustment for adjusting the actuator such as the step motor so that the gate 11 is in the closed state and the open state. It is preferable to keep it. The empty weight change output Wv may be an average of a plurality of weight change outputs obtained by driving the empty weighing hopper 1 to open and close a plurality of times.

  When the discharge determination process is started, first, the number H of the weighing hoppers 1 selected for the discharge combination (currently being discharged) is stored in the storage unit 32 (step SB1). Then, variable h = 1 is set as an initial state (step SB2).

  The control unit 31 reads the discharge weight change output for one of the weighing hoppers 1 selected for the discharge combination (step SB3), and reads the empty weight change output Wv (step SB4). Then, the control unit 31 functioning as the discharge determination unit 31a compares the discharge weight change output Wx with the empty weight change output Wv (step SB5). More specifically, the control unit 31 determines whether or not the difference between the discharge weight change output Wx and the empty weight change output Wv is within a predetermined allowable range.

  As a result of the comparison, when there is only a difference within a predetermined allowable range between the discharge weight change output Wx and the empty weight change output Wv (No in Step SB5), the control unit 31 is normal from the weighing hopper 1 It is determined that the object to be weighed was discharged (no discharge defect). Then, the control unit 31 determines whether or not the variable h is the number H of the weighing hoppers 1 selected for the discharge combination (step SB6). If h = H is not satisfied (No in step SB6), the variable h is set. A process of adding 1 is performed (step SB7). That is, the same determination process is performed for the weighing hoppers 1 that have not been determined among the weighing hoppers 1 selected for the discharge combination (steps SB3 to SB5). The control unit 31 performs the determination process for all the weighing hoppers 1 selected as the discharge combination, and when it is determined that there is no discharge failure (Yes in Step SB6), the discharge determination process ends. As a result, the weight of the object to be weighed discharged from the weighing hopper 1 becomes substantially equal to the combined weight calculated by the combination calculation.

  As a result of the comparison, when the difference between the empty weight change output Wv and the discharge weight change output Wx is outside the allowable range (Yes in step SB5), the control unit 31 completely discharges the object to be weighed from the weighing hopper 1. It is determined that it has not been performed, and the operation setting display device 8 functioning as a notification unit is notified that a discharge failure has occurred (step SB8). For example, here, when the discharge weight change output Wx is heavier than the empty weight change output Wv beyond a predetermined allowable range, the operation setting display device 8 is notified that a discharge failure has occurred. The notification mode is not particularly limited. For example, the notification is performed by switching the display screen of the operation setting display device 8 to an error display, blinking the display screen, or generating an error notification sound. In addition, a siren, an error lamp, or the like may be provided in the combination weigher separately from the operation setting display device 8, and the discharge failure may be notified by sound or light according to the determination result in the control unit 31.

  Furthermore, it is preferable that the control unit 31 performs a discharge failure notification and processes the object to be weighed this time as a discharge failure. Specifically, for example, a hopper may be provided instead of the discharge chute 62 of the collective discharge unit 6, and the discharge process may be stopped after the hopper is closed. Alternatively, for example, on the downstream side of the discharge chute 62, a discharge path for discharging the objects to be weighed is provided separately from the supply path for supplying the objects to be packed to the packaging machine. It is configured so that the weighing object is discharged. Furthermore, it is also possible to stop the packaging process in the packaging machine by transmitting an error signal to the packaging machine provided downstream of the collective discharge unit 6 of the combination weigher.

  As described above, according to the combination weigher to which the weighing device having the above-described configuration is applied, when a discharge failure of the weighing object occurs, the opening / closing operation of the gate 11 of the weighing hopper 1 to which the weighing object is supplied. It is detected that the weight change in the inside is different from the weight change during the opening / closing operation of the gate 11 of the weighing hopper 1 in a state in which the object to be weighed is not held. Can be detected quickly and reliably. Further, when the difference between the empty weight change output Wv and the discharge weight change output Wx is calculated and it is determined that the difference between the empty weight change output Wv and the discharge weight change output Wx is greater than or equal to a predetermined value, Since it is notified that the discharge failure has occurred, it is possible to prevent the discharge failure from being erroneously detected.

  In this embodiment, the empty weight change output Wv and the discharge weight change output Wx are digital outputs obtained by digitizing the output from the weight sensor 2, and the control unit 31 functioning as the discharge determination unit 31a detects the weighing hopper weight change. In a predetermined sampling period in the period T, the difference between the sums of the weight values sampled from the empty weight change output Wv and the discharge weight change output Wx is calculated. As a result, the empty weight change output Wv and the discharge weight change output Wx, which are digital data, are sampled and added together in a predetermined sampling period, and are compared with each other, so a special control mechanism and control program are almost added. It is possible to perform a quick calculation without any problems. The empty weight change output Wv and the discharge weight change output Wx may be obtained by performing predetermined filter processing on the sampling data. As a result, vibration components that are not related to the change in the discharged weight, such as the natural vibration of the weight sensor 2 itself, can be removed, so that more accurate determination can be performed.

  Below, the comparison aspect of empty weight change output Wv and discharge weight change output Wx in this embodiment is demonstrated. 6 and 7 are graphs showing examples of empty weight change output and discharge weight change output of the weighing hopper of the combination weigher shown in FIG. FIG. 6 shows a discharge weight change output when the object to be weighed is normally discharged from the weighing hopper, and FIG. 7 shows a discharge weight change output when a discharge failure of the object to be measured occurs in the weighing hopper. Yes.

  In the graphs of FIGS. 6 and 7, the horizontal axis indicates the passage of time as the number of samplings at predetermined time intervals. The vertical axis represents the weight value detected by the weight sensor 2 as a digital conversion value. The discharge weight change output Wx in FIGS. 6 and 7 shows the weight change output when the weighing hopper 1 holding 110 g of the object to be measured is discharged. The discharge weight change output Wx in FIG. The weight change output when the total amount (110 g) of the weighing object could not be discharged is shown. This is an event that can actually occur, for example, when a resilient food such as a winner sausage is caught in the weighing hopper 1. Further, in the examples of FIG. 6 and FIG. 7, a waveform is shown that does not reach the weighing hopper (no new weighing object is supplied) at time t5 when the new weighing object reaches the weighing hopper.

  As shown in FIGS. 6 and 7, the weight value detected by the weight sensor 2 when the weighing hopper 1 is swung by the opening and closing operation of the weighing hopper 1 for both the empty weight change output Wv and the discharge weight change output Wx. Is changing irregularly. However, the inventor of the present invention shows that the empty weight change Wv as shown in FIGS. 6 and 7 has substantially the same waveform under the same conditions (for example, the shape, weight, opening / closing speed, etc. of the weighing hopper 1). It became clear by experiment. As shown in FIG. 6, the discharge weight change Wx in the weighing hopper 1 in which the entire amount of the weighing object has been discharged normally is the weighing object held in the weighing hopper 1 within the weighing hopper weight change detection period T. It has been clarified through experiments that the total amount of the waveform becomes substantially the same waveform after time ts away from the weighing hopper 1. Therefore, at the time of normal discharge, the difference between the empty weight change output Wv and the discharge weight change output Wx in the weighing hopper weight change detection period T falls within a predetermined allowable range.

  On the other hand, if the object to be weighed is not normally discharged due to being caught by the weighing hopper 1, the waveforms of the empty weight change output Wv and the discharge weight change output Wx are the same even after the time ts has elapsed, as shown in FIG. At any time, the waveform of the discharge weight change output Wx changes in a state of being increased by a substantially constant weight with respect to the waveform of the empty weight change output Wv. That is, the value obtained by subtracting the empty weight change output Wv from the discharge weight change output Wx at any time indicates the weight of the object to be weighed that has not been discharged by the weighing hopper 1 (110 g in the example of FIG. 7). Therefore, at the time of discharge failure, the difference between the empty weight change output Wv and the discharge weight change output Wx in the weighing hopper weight change detection period T exceeds the allowable range.

  In order to realize the comparison between the empty weight change output Wv and the discharge weight change output Wx in the weighing hopper weight change detection period T, in this embodiment, the control unit 31 functioning as the discharge determination unit 31a For each of the change output Wv and the discharge weight change output Wx, the data sampled in the weighing hopper weight change detection period T is integrated in order, and it is determined whether or not the sum (or average) difference is within an allowable range. The comparison method is not limited to this. For example, one or a plurality of sampling data at a predetermined time within the weighing hopper weight change detection period T may be compared.

  The control unit 31 functioning as the discharge determination unit 31a may compare the empty weight change output Wv and the discharge weight change output Wx during the entire period of the weighing hopper weight change detection period T, or may compare them during a partial period. Good.

  For example, the control unit 31 functioning as the discharge determination means 31a includes the empty weight after the comparison start with reference to the time t2 when the gate 11 of the weighing hopper 1 is opened in the weighing hopper weight change detection period T. A difference between the change output Wv and the discharge weight change output Wx may be calculated. When the gate 11 of the weighing hopper 1 is in the open state, all the objects to be weighed held by the weighing hopper 1 should be separated from the weighing hopper 1 unless there is a defective discharge. Accordingly, by setting the comparison start time with reference to the time t2 when the gate 11 of the weighing hopper 1 is opened, the waveform change during normal operation of the empty weight change output Wv and the discharge weight change output Wx in the comparison range can be further increased. Since they can be matched, the discharge failure of the weighing hopper 1 can be detected more reliably. Note that the comparison start time t2 is not limited to starting the calculation from the sampling data at the time t2, but also from the sampling data after a predetermined time from the time t2 or a predetermined time before the time t2. Includes concepts to get you started.

  Further, for example, the control unit 31 functioning as the discharge determination unit 31a includes, before the end of the comparison with respect to the time t4 when the gate 11 of the weighing hopper 1 is closed in the weighing hopper weight change detection period T. The difference between the empty weight change output Wv and the discharge weight change output Wx may be calculated. When an object to be weighed is newly supplied to the weighing hopper 1 before the weighing hopper 1 is closed, the discharge weight change output Wx before the object to be weighed is supplied to the weighing hopper 1 is changed to the empty weight. It is preferable to compare with the output Wv. Therefore, by setting the time when the comparison is completed as a reference, the time t4 when the gate 11 of the weighing hopper 1 is closed is supplied to the weighing hopper 1 that has detected the discharge weight change output Wx. , While quickly supplying the objects to be weighed to the weighing hopper 1, the waveform change in the normal state of the empty weight change output Wv and the discharge weight change output Wx in the comparison range is made more consistent, thereby further reducing the discharge failure of the weighing hopper 1. It can be detected reliably. Note that when the comparison with respect to time t4 is completed, not only the calculation is started from the sampling data at time t4, but also the calculation is performed from the sampling data after a predetermined time elapses from time t4 or a predetermined time before time t4. Includes concepts to get you started.

  Further, for example, the control unit 31 functioning as the discharge determination means 31a is configured so that the gate 41 of the supply hopper 4 corresponding to the weighing hopper 1 that has detected the discharge weight change output Wx in the weighing hopper weight change detection period T is in the closed state. The difference between the empty weight change output Wv and the discharge weight change output Wx may be calculated before the end of the comparison with reference to the opening time t3. As in the present embodiment, when a new object to be weighed is supplied from the supply hopper 4 to the weighing hopper 1 before the weighing hopper 1 is closed, before the object to be weighed is supplied to the weighing hopper 1. It is preferable to compare the discharged weight change output Wx up to the empty weight change output Wv. Accordingly, by setting the end of the comparison based on the time t3 when the gate 41 of the supply hopper 4 corresponding to the weighing hopper 1 that has detected the discharge weight change output Wx starts to open from the closed state, the object to be weighed to the weighing hopper 1 is set. Can be quickly detected, and the change in waveform of the empty weight change output Wv and the discharge weight change output Wx in the comparison range at the normal time can be matched to detect discharge failure of the weighing hopper 1 more reliably. Note that when the comparison with respect to time t3 is ended, not only the calculation is started from the sampling data at time t3, but also the calculation is performed from the sampling data after a predetermined time from time t3 or before a predetermined time from time t3. Includes concepts to get you started.

  The use of the weighing device of the present embodiment and the combination weigher using the weighing device is suitable for a weighing device for weighing an object to be weighed easily on a weighing hopper and a combination weigher equipped with the weighing device. In particular, a weighing device for weighing relatively large objects to be weighed such as sausages, chikuwa, kneaded products, etc., and objects to be weighed such as cherry tomatoes, peppers, potatoes, etc., and a combination weigher equipped therewith It is suitable for etc. In addition, as described in the present embodiment, the detection of the change in weight during the opening / closing operation of the gate 11 of the weighing hopper 1 is not higher in weighing accuracy than the weight detection when the weighing hopper 1 is stable, but as described above. In such a relatively large object to be weighed, it is possible to detect the discharge defect of the object to be weighed sufficiently accurately even if the weighing accuracy is not high. Accordingly, the weighing device of this embodiment and the combination weigher using the same are also used for weighing an object to be weighed that does not need to have high weighing accuracy during the opening / closing operation of the gate 11 for detecting such discharge failure. It can be suitably used.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various improvements, changes, and modifications can be made without departing from the spirit of the present invention.

  INDUSTRIAL APPLICABILITY The weighing device of the present invention and the combination weigher equipped with the weighing device are useful as a weighing device for weighing an object to be weighed easily on a weighing hopper and a combination weigher equipped with the weighing device. In particular, a weighing device for weighing relatively large objects to be weighed such as sausages, chikuwa, kneaded products, etc., and objects to be weighed such as cherry tomatoes, peppers, potatoes, etc., and a combination weigher equipped therewith Etc. are useful.

DESCRIPTION OF SYMBOLS 1 Weighing hopper 2 Weight sensor 3 Control apparatus 4 Supply hopper 5 Supply part 6 Collecting discharge part 8 Operation setting display apparatus 9 Level detector 10 External supply apparatus 11 Gate 30 of measurement hopper Control board 31 Control part (discharge determination means, control) means)
31a Ejection determination means 31b Control means 32 Storage part (storage means)
41 Gate of Supply Hopper 51 Main Feeder 52 Straight Feeder 61 Collecting Chute 62 Discharge Chute 511 Top Cone 512, 522 Vibrator 521 Straight Feeder Pan

Claims (5)

A weighing hopper that has an openable and closable gate, and discharges the temporarily held object by opening the gate;
A weight sensor for detecting the weight of the weighing hopper including an object to be weighed held by the weighing hopper;
Control means for opening and closing the gate;
In the weighing hopper in a state in which the object to be weighed is not charged, a period until the new object is reached after the gate is closed again from the closed state (hereinafter referred to as a weighing hopper weight change detection period). Storage means for previously storing the output of the weight sensor (hereinafter referred to as empty weight change output);
In the weighing hopper with an object to be weighed in, the output of the weight sensor during the weighing hopper weight change detection period (hereinafter referred to as discharge weight change output) is detected, and the empty weight change stored in the storage means and a discharge failure detecting means for detecting that a discharge error occurs in the objects to be weighed on the basis of the difference between the output and the discharge weight change output,
The discharge failure detection means detects the discharge weight change output in a weighing hopper in a state where an object to be weighed is inserted, and a difference between the empty weight change output stored in the storage means and the discharge weight change output is determined. A discharge determination unit that determines whether or not a predetermined value or more, and an object to be weighed when the discharge determination unit determines that the difference between the empty weight change output and the discharge weight change output is a predetermined value or more. And informing means for informing that a discharge failure has occurred,
The empty weight change output and the discharge weight change output are digital outputs obtained by digitizing the output from the weight sensor,
The discharge determination means is configured to calculate a difference between sums of weight values sampled from the empty weight change output and the discharge weight change output in a predetermined sampling period of the weighing hopper weight change detection period. The weighing device. The discharge determination means includes the empty weight change output and the discharge weight change output after the comparison start with reference to the time when the gate of the weighing hopper is opened in the weighing hopper weight change detection period. The weighing device according to claim 1 , wherein the weighing device is configured to calculate a difference between the weighing device and the weighing device. The discharge determination means includes the empty weight change output and the discharge weight change output before the end of the comparison with respect to a time when the gate of the weighing hopper is in a closed state in the weighing hopper weight change detection period. The weighing device according to claim 1 , wherein the weighing device is configured to calculate a difference between the weighing device and the weighing device. A supply hopper disposed on the upstream side of the weighing hopper and supplying an object to be weighed to the weighing hopper using a gate that can be opened and closed;
The discharge determination means sets, as a comparison end time, a time when the gate of the supply hopper corresponding to the weighing hopper that has detected the discharged weight change output starts to open from a closed state in the weighing hopper weight change detection period. 2. The weighing apparatus according to claim 1 , wherein the weighing device is configured to calculate a difference between the empty weight change output and the discharged weight change output before the end of the comparison. Combination weigher having a metering device according to any one of claims 1 to 4.