JP2010249590A - Feeder for digital balance and digital balance equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a feeder for a digital balance which estimates the transport amount of an object to be weighed with high precision regardless of a temporal change in the vibration of the feeder for a digital balance and a digital balance equipped with the same. <P>SOLUTION: A strain detection member 3 as an amplitude detection means detects the vibration amplitude a of a feeder pan 1 caused by a vibrator 2 (Step S104). A control unit 41 functions as a transfer amount calculation means 41b and integrates the temporal change of the vibration amplitude a of the feeder pan 1 detected by the strain detection member 3 to calculate an estimated transport amount Σ of the object to be weighed (Step S108). In addition, the control unit 41 functions as a control means 41a and controls at least either one of the drive amplitude and drive time of the vibrator 2 on the basis of the estimated transport amount Σ. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a digital scale feeder and a digital scale equipped with the same, and in particular, a digital scale feeder that conveys an object to be weighed by vibrating a feeder pan on which the object to be weighed is placed by a vibration device, and the same. It relates to the digital scale provided.

  In a digital scale feeder provided on a digital scale such as a combination scale, the amplitude or drive time for vibrating the feeder pan by the vibration device is set in advance so that a predetermined supply amount is conveyed. Supply. That is, when changing the supply amount of the object to be weighed, the vibration amplitude or driving time of the feeder is reset.

  As an index for resetting the vibration amplitude or driving time of the feeder when the supply amount of the object to be weighed is changed, a configuration for estimating the supply amount of the object to be weighed by the feeder as in Patent Document 1 is known. It has become. That is, in Patent Document 1, a means for weighing an object to be weighed on the feeder pan is provided, and the supply amount is estimated from the set value of the vibration amplitude, the driving time and the weight of the object to be weighed on the feeder pan. Yes.

Japanese Patent Laid-Open No. 11-227717

  However, since the vibration amplitude of the feeder pan changes with time depending on the supply amount of the object to be weighed and does not become a constant value, the estimation method as in Patent Document 1 has a large error. Further, in Patent Document 1, the weight of the object to be weighed on the feeder pan is measured and the supply amount is estimated based on this, but the feeder is also being measured while the weight of the object to be weighed on the feeder pan is being measured. Since the objects to be weighed are sequentially supplied to the pan from the upstream supply device, vibration due to the objects to be weighed supplied to the feeder pan is applied as a vibration component of the feeder pan, increasing the weight of the object to be weighed on the feeder pan. It cannot be measured accurately. Therefore, such a method for estimating the supply amount of the object to be weighed using the weight of the object to be weighed on the feeder pan cannot maintain high accuracy.

  The present invention has been made to solve the above-described problems, and a digital balance capable of accurately estimating the transport amount of an object to be weighed regardless of temporal changes in vibration in a digital scale feeder. An object of the present invention is to provide a feeder for use and a digital scale equipped with the feeder.

  A feeder for a digital scale according to the present invention includes a feeder pan on which an object to be weighed is placed, a vibration device that vibrates the feeder pan, and a control unit that controls the vibration device, and the control unit includes the vibration unit. A digital weighing feeder that controls an apparatus to convey an object to be weighed on the feeder pan, the amplitude detecting means for detecting the vibration amplitude of the feeder pan generated by the vibration device, and the temporal change of the vibration amplitude Transport amount calculating means for calculating the estimated transport amount of the object to be weighed, and the control means calculates at least one of the drive amplitude and the drive time of the vibration device based on the estimated transport amount. Configured to control.

  According to the digital weighing feeder having the above-described configuration, the vibration amplitude of the digital weighing feeder actually generated is detected, and the estimated transport amount of the object to be weighed is calculated by integrating the temporal change of the vibration amplitude. Therefore, the conveyance amount of the object to be weighed can be estimated with high accuracy regardless of the temporal change of vibration in the digital scale feeder, and fine drive control can be performed on the vibration device of the digital scale feeder. it can.

  The transport amount calculating means calculates an approximate expression from the temporal change of the vibration amplitude, calculates the estimated transport amount of the object to be measured by integrating the approximate expression, and the control means calculates an integral value of the approximate expression. Based on the above, it may be configured to control at least one of the drive amplitude and the drive time of the vibration device. According to this configuration, since the temporal change of the vibration amplitude is approximated and integrated, the amount of calculation of the estimated conveyance amount can be reduced. In addition, the vibration device is controlled based on an integral value of an approximate expression approximating a temporal change in vibration amplitude. For example, in order to halve the transport amount, an integral time in which the integral value of the approximate expression is halved in the same approximate expression is set to the driving time of the vibration device, or the integral value of the approximate expression is equal to the integral time in the same integral time. The amplitude corresponding to the approximate expression that is halved is set as the drive amplitude of the vibration device. In this way, the control amount can be easily set using the integral value of the approximate expression, and drive control of the vibration device can be easily performed.

  Further, the digital weighing feeder includes a weighing hopper that holds and discharges an object to be weighed conveyed by the digital weighing feeder, and a weighing means for detecting the weight of the weighing object held by the weighing hopper. Storage means for storing the weight of the object to be weighed obtained by the digital scale provided and storing the correlation between the weight and the estimated transport amount in advance, and the correlation stored in the storage means An estimated transport weight calculating means for calculating an estimated transport weight of the object to be weighed from an estimated transport amount of the object to be weighed, a difference between the estimated transport weight and the weighed weight, and the difference being a predetermined allowable value In the case described above, a correction unit that corrects the correlation may be provided. According to this configuration, the estimated transport weight of the object to be calculated calculated using the correlation from the estimated transport amount of the object to be measured is compared with the measured weight actually measured in the weighing hopper, and the estimated transport weight and the weighing weight are compared. In order to correct the correlation, the estimated transport weight estimated according to the actual feeder vibration condition can be easily brought close to the actual measured weight. Therefore, it is possible to perform feeder drive control with higher accuracy.

  The correlation may be a proportional relationship having a predetermined proportional coefficient, and the correction unit may be configured to correct the proportional coefficient when the difference is equal to or greater than a predetermined allowable value. As a result, since the correlation between the estimated transport weight and the actual measured weight is set as a proportional relationship having a predetermined proportional coefficient, the estimated transport weight can be easily calculated and the proportional coefficient can be easily corrected. Can do.

  The digital scale according to the present invention includes a digital scale feeder having the above-described configuration, a weighing hopper that holds and discharges an object to be weighed conveyed by the digital scale feeder, and an object to be weighed held by the weighing hopper. Weighing means for detecting the weight of According to the digital scale of the present invention, since the digital scale feeder having the above-described configuration is provided, the digital scale feeder is finely tuned with respect to the vibration device of the digital scale feeder regardless of temporal changes in vibration in the digital scale feeder. Drive control can be performed with higher accuracy.

  Hereinafter, definitions of terms used in claims and description will be described.

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

  The “weighing means” in the claims and specification includes a weight sensor for detecting the weight of the weighing hopper, and the weight of the object to be weighed held by the weighing hopper based on the weight detected by the weight sensor. It is a concept including a calculation means for calculating (weighing) and a storage means for storing the weight of the object to be measured calculated by the calculation means.

  The present invention is configured as described above, and can accurately estimate the transport amount of an object to be weighed regardless of temporal changes in vibration in the digital scale feeder. On the other hand, there is an effect that fine drive control can be performed.

It is a perspective view which shows the feeder for digital scales which concerns on one Embodiment of this invention. It is sectional drawing which shows the schematic structure of the digital balance to which the feeder for digital scales shown in FIG. 1 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 digital balance shown in FIG. It is a flowchart which shows the control operation of the feeder for digital scales shown in FIG. It is a flowchart which shows the control action in the drive correction process of the feeder for digital scales shown in FIG. It is a graph which compares and shows the drive signal and detection waveform at the time of driving a vibration apparatus in the state which mounted the to-be-measured object on the feeder pan using the feeder of this embodiment. It is a graph which compares and shows the drive signal and detection waveform at the time of supplying a to-be-measured object on a feeder pan, using the feeder of this embodiment and driving a vibration apparatus. It is the graph which expands and shows partially what overlapped the corresponding approximate curve on the detection waveform shown in FIG.

  Embodiments of the present invention will be described below 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. FIG. 1 is a perspective view showing a feeder for a digital scale according to an embodiment of the present invention.

  As shown in FIG. 1, the digital balance feeder 10 according to the present embodiment includes a feeder pan 1 on which an object to be weighed is placed and a vibration device 2 that vibrates the feeder pan 1. The feeder pan 1 is formed in a trough shape, for example. The vibration device 2 includes a fixed frame 21 fixed to a digital scale (not shown) and a movable frame 22 to which the feeder pan 1 is fixed and can swing with respect to the fixed frame 21 in the vertical direction and the conveyance direction (front-rear direction). And a vibrator 23 that is provided between the fixed frame 21 and the movable frame 22 and vibrates the movable frame 22 with respect to the fixed frame 21, and both ends are fixed to the fixed frame 21 and the movable frame 22, respectively. The elastic members 24A and 24B are elastically deformable in accordance with the vibration of the movable frame 22 with respect to 21. In addition, one of the elastic members 24A and 24B (the front elastic member 24A in FIG. 1) of the vibration device 2 is provided with a strain detection member 3 that detects the strain of the elastic member.

  The fixed frame 21 is fixed to the digital scale via a vibration-proof spring 25. The elastic members 24A and 24B are constituted by a pair of leaf springs 24A and 24B, for example. A base end portion of one leaf spring 24 </ b> A extending in the vertical direction is fixed to the front end portion of the fixed frame 21. A base end portion of the other leaf spring 24B that is inclined rearward and extends upward is fixed to the rear end portion of the fixed frame 21. The front end portion and the rear end portion of the movable frame 22 are fixed to the upper end portion of one leaf spring 24A and the upper end portion of the other leaf spring 24B, respectively. The movable frame 22 is fixed so as to extend horizontally. A suction plate fixing portion 22a is formed at the front end of the movable frame 22 so as to extend downward. An adsorbed plate (armature) 27 made of a material attracted by a magnetic force such as iron is fixed to the adsorbed plate fixing portion 22a. The vibrator 23 is formed of a magnet coil, and is disposed on the fixed frame 21 so as to face the attracted plate 27. The feeder pan 1 is attached to the movable frame 22 so as to extend in the front-rear direction. The feeder pan 1 is detachably attached to the movable frame 22 by a mounting bracket 26. Thus, when the vibrator 23 is turned on, the attracted plate 27 fixed to the movable frame 22 is attracted to the vibrator 23 and the pair of leaf springs 24A and 24B bend backward. Thereby, the feeder pan 1 moves backward and downward from the initial position. When the vibrator 23 is turned off, the attracted plate 27 fixed to the movable frame 22 is released from the suction force of the vibrator 23 and the pair of leaf springs 24A and 24B are moved forward by the elastic repulsion force. Turn to. As a result, the feeder pan 1 moves forward and upward from the lower position beyond the initial position. Therefore, when the vibrator 23 is turned on and off, the feeder pan 1 is vibrated in the vertical direction and the front-rear direction. The object to be weighed on the feeder pan 1 is conveyed forward by this vibration. The strain detection member 3 is configured by, for example, a piezoelectric element such as a piezo film attached to the leaf spring 24A, and detects the amount of elastic deformation of the leaf spring 24A. That is, when the strain detection member 3 is distorted according to the elastic deformation of the leaf spring 24A, which is an elastic member, the strain detection member 3 outputs a voltage according to the strain. The amount of elastic deformation is detected by detecting. Thus, the control device 4 and the strain detection member 3 function as an amplitude detection unit that detects the vibration amplitude of the feeder pan 1 by detecting the amount of elastic deformation of the elastic member 24. The amplitude detection means is not limited to the configuration using the strain detection member, and for example, a laser displacement meter, a Hall element, an eddy current meter, or the like may be used.

  FIG. 2 is a cross-sectional view showing a schematic configuration of a digital balance to which the digital balance feeder shown in FIG. 1 is applied as viewed from the side. FIG. 3 is a block diagram showing a schematic configuration of a control system of the digital balance shown in FIG. The digital scale in the present embodiment is a fully automatic combination scale 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. The digital scale to which the digital scale feeder 10 of the present invention is applied is not limited to this as long as it is a digital scale capable of supplying an object to be weighed using the digital scale feeder 10.

  The digital balance of this embodiment has a plurality of (for example, 14) weighing hoppers 5. The plurality of weighing hoppers 5 are arranged, for example, in a circular shape (circumferentially), but may be arranged in other modes (an elliptical shape, a linear shape, etc.). The plurality of weighing hoppers 5 temporarily hold the objects to be weighed supplied from above, and discharge the objects to be weighed downward by opening the gate 51 that can be opened and closed provided at the lower part. Each of the plurality of weighing hoppers 5 is supported by a weight sensor 6 that detects the weight of the weighing hopper 5. For the weight sensor 6, for example, a load cell is used. The weight sensor 6 is connected to the control device 4, and the weight measured by the weight sensor 6 is transmitted to the control device 4. Here, since the weight of the weighing hopper 5 is known, the control device 4 subtracts the weight of the weighing hopper 5 from the weight detected by the weight sensor 6 to hold the weighing object held by the weighing hopper 5. Weigh the weight. Thus, the weight sensor 6 for detecting the weight of the weighing hopper 5 in the present embodiment, and the calculation means for calculating the weight of the object to be weighed held by the weighing hopper 5 based on the weight detected by the weight sensor 6. The control device 4 functioning as a component constitutes a measuring means.

  The weighing hopper 5 means a hopper mechanism that can weigh the weighing hopper 5 including the object to be weighed by the weighing means. That is, the digital scale may be configured such that the memory hopper is disposed downstream of the weighing hopper 5. In this case, the weight of the object to be weighed held by the memory hopper is weighed by the corresponding (upstream) weighing hopper 5 and stored in association with the control device 4.

  A supply hopper 7 is provided upstream of the weighing hopper 5. In the present embodiment, a plurality of supply hoppers 7 are respectively disposed above the plurality of weighing hoppers 5. The supply hopper 7 temporarily holds an object to be weighed supplied from above, and discharges the object to be weighed downward by opening a gate 71 that can be opened and closed provided below the object.

  A supply unit 50 including a digital weighing feeder 10 is provided upstream of the supply hopper 7. The supply unit 50 feeds the object to be weighed supplied from the external supply device 100 to the center of the combination weigher radially by vibration and the object to be weighed sent from the main feeder 11 by vibration. A digital weighing feeder 10 which is a plurality of linear feeders. The main feeder 11 includes a conical top cone 111 disposed below the supply port of the external supply device 100 and a vibrator 112 that vibrates the top cone 111 in the vertical direction. The vibrator 112 vibrates the top cone 111 by, for example, continuously switching on and off of the electromagnet. The plurality of feeders 10 are provided corresponding to the supply hoppers 7, and the objects to be weighed sent by the plurality of feeders 10 are supplied to the corresponding supply hoppers 7. As described above, the combination weigher of this embodiment is provided with a plurality of sets of head units each including the feeder 10, the supply hopper 7, the weighing hopper 5, and the weight sensor 6.

  Downstream of the weighing hopper 5, there is disposed a collective discharge unit 8 that collects the objects to be weighed held in one or a plurality of weighing hoppers 5 selected for the discharge combination described later and discharges them outside the apparatus. . The collective discharge unit 8 includes an inverted conical collective chute 81 and a discharge chute 82 disposed below the collective chute 81. The objects to be weighed discharged from one or a plurality of weighing hoppers 5 through the gate 51 are gathered by sliding down the collecting chute 81, and the packaging machine outside the machine is passed through the discharging chute 82 provided below the collecting chute 81 (see FIG. (Not shown). The collective discharge unit 8 may have a configuration in which a hopper is disposed at the position of the discharge chute 82.

  In this embodiment, the control device 4 includes one or more combinations of the weights of the objects to be weighed measured by the weighing means including the weight sensor 6 and the control device 4 from the weighing hoppers 5 holding the objects to be weighed. A combination calculation for selecting a combination of the weighing hoppers 5 in which the sum of the weights within a predetermined range including the target combination weight is a combination of the weighing hoppers 5 to discharge the objects to be weighed (hereinafter referred to as discharge combinations). It is configured.

  The control device 4 further performs opening / closing control of the gate 71 of each supply hopper 7 and gate 51 of each weighing hopper 5 and supply control of the supply unit 50. The combination weigher of this embodiment includes an operation setting display device 9 that can perform various operation settings and display the settings. And this control apparatus 4 functions also as the control means 41a which controls the vibration apparatus 2 of the feeder for digital scales.

  2 and 3, the combination weigher of the present embodiment includes a supply level detector 12 that detects the supply status of an object to be weighed from the external supply device 100 to the top cone 111 of the main feeder 11. I have. The supply level detector 12 and the external supply device 100 are respectively connected to the control device 4, and the control device 4 detects the object to be weighed according to the supply status of the object to be weighed detected by the supply level detector 12. The external supply device 100 is controlled so as to change the supply amount. The external supply device 100 may be, for example, a belt conveyor or a device that vibrates a trough-shaped supply pan. The supply level detector 12 can be composed of, for example, a weight sensor that detects the weight of an object to be weighed on the top cone 111, a level sensor that similarly detects the layer thickness, and the like.

  As illustrated in FIG. 3, the control device 4 includes, for example, a control board (not shown) having a control unit 41 and a storage unit 42. The control device 4 includes, for example, a microcomputer, and the control unit 41 uses, for example, a CPU of this microcomputer. For example, an internal memory of the microcomputer is used for the storage unit 42. The control unit 41 and the storage unit 42 are connected to each other. The storage unit 42 stores a control program. Further, the storage unit 42 stores various data. In addition, the control unit 41 reads out and executes the control program stored in the storage unit 42 to perform processing and control such as calculation. Specifically, the control unit 41 receives signals from the strain detection member 3 and the weight sensor 6, performs calculations based on these signals, and stores these calculation results in the storage unit 42. Further, based on these signals, a control signal is transmitted to the vibration device 2 for control. In other words, the control unit 41 functions as a control unit 41a, a conveyance amount calculation unit 41b, an estimated conveyance weight calculation unit 41c, and a correction unit 41d.

  In the present embodiment, the control device 4 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 4 may be configured by the plurality of control boards. Further, in the present embodiment, the control device 4 is configured as the control device 4 of the digital balance provided with the digital balance feeder 10, but a control device dedicated to the feeder 10 is provided separately from the control device of the digital scale. It is good. Furthermore, for example, the feeder 10 may be controlled by the external control device by connecting a personal computer or the like as the external control device. In FIG. 3, only one set of head portions is shown, but in a digital scale equipped with a plurality of head portions, a plurality of head portions are connected to the control device 4, respectively.

  Below, operation | movement of the control apparatus 4 is demonstrated in order. In the storage unit 42, a correlation between an estimated transport amount Σ and an estimated transport weight Wk, which will be described later, is stored in advance. The correlation in the present embodiment is a proportional relationship, and the storage unit 42 stores a predetermined proportional coefficient K. That is, the estimated transport weight Wk is a value obtained by multiplying the estimated transport amount Σ by the proportional coefficient K.

  When the control device 4 receives a feeder drive command for supplying an object to be weighed to the weighing hopper 5 of the digital balance after the digital balance including the feeder 10 is activated (Yes in step S101), the control unit 41 controls the control means 41a. And a drive signal is sent to the vibration device 2, and the feeder pan 1 is vibrated to start conveying the object to be weighed (step S102). The feeder driving command is a feeder driving signal sent from the digital balance control device to the feeder 10 control device when the digital balance control device and the feeder 10 control device are different. In the configuration as in the present embodiment in which the apparatus and the control device of the feeder 10 are the same, an instruction in the control program may be used.

  Simultaneously with the start of driving of the feeder 10, the control unit 41 counts the driving time t by an internal timer or the like (step S103).

  The control unit 41 functions as a conveyance amount calculation unit 41b, and calculates the estimated conveyance amount of the object to be measured by integrating the temporal change of the vibration amplitude a of the feeder pan 1 detected by the distortion detection member 3. Specifically, first, the control unit 41 detects the vibration amplitude a of the feeder 10 from the strain detection member 3 that is an amplitude detection means, and stores it in association with the drive time t (step S104).

  After detecting the vibration amplitude a of the feeder 10, the control unit 41 determines whether or not the drive time t has reached the target drive time T (step S105). When the driving time t has not reached the target driving time T (No in step S105), the driving of the feeder 10 is continued, and similarly, the driving amplitude a of the feeder 10 is detected from the distortion detecting member 3, and the driving time t Are stored in association with each other (step S104). When the drive time t has reached the target drive time T (Yes in Step S105), the control unit 41 stops driving the vibration device 2 (Step S106).

  Then, the control unit 41 integrates the vibration amplitude a of the feeder 10 stored in the storage unit 42. In the present embodiment, the control unit 41 functioning as the transport amount calculating means 41b calculates the approximate expression F from the temporal change of the vibration amplitude a (step S107), and integrates the approximate expression F to estimate the object to be weighed. The carry amount Σ is calculated (step S108).

  For example, the approximate expression F can be set to a function F = Vsin (2πtf) related to the driving time t. Here, V is the maximum value of the vibration amplitude a detected by the strain detection member 3, and f is the drive frequency of the vibration device 2. The driving frequency of the vibration device 2 may be input by an operator, or the rated value of the vibration device 2 may be set in advance. Or it is good also as detecting the drive frequency of the vibration apparatus 2 separately, and setting the detected value as f.

  In the present embodiment, the value of V is set for each period of the drive signal of the vibration device 2. That is, a different value of V is set for each time t = n / f at which 2πft = 2nπ (n is an integer) in the approximate expression F. That is, the approximate expression F in the present embodiment is set for each period of the drive signal of the vibration device 2.

In this case, the storage unit 42 stores an approximate expression F = Vsin (2πtf) in advance. In step S104, the control unit 41 sets the maximum value among the vibration amplitudes a detected at a plurality of times in the cycle to V in the cycle. Accordingly, the plurality of approximate expressions Fn are expressed as follows.
F1 = V1sin (2πft) (0 <t <1 / f)
F2 = V2sin (2πft) (1 / f <t <2 / f)
F3 = V3sin (2πft) (2 / f <t <3 / f)
...
Fn = Vnsin (2πft) ((n−1) / f <t <n / f)
The control unit 41 calculates the estimated transport amount Σ of the object to be weighed by integrating and adding together the plurality of approximate expressions Fn set in this way with the driving time t. That is, the control unit 41 calculates the estimated transport amount Σ = ∫F1 · dt + ∫F2 · dt +... + ∫Fn · dt +.

  It should be noted that the maximum amplitude among the vibration amplitudes a detected in one conveyance cycle (from the time when the drive signal of the vibration device 2 is turned on until it is turned off) stored in the storage unit 42 is set to V in the approximate expression F. The driving frequency of the vibration device 2 may be set to f.

  Further, when integrating the approximate expression F, the area to be obtained may be obtained by integrating only the + side (conveying direction) or by integrating both the + side and the − side. Alternatively, one cycle of the absolute value of the approximate expression F may be integrated and divided by 2. Further, the approximate expression F is not limited to the above, and may be an expression obtained using, for example, the least square method.

  In the transport of the object to be weighed after the next time, the control unit 41 functions as the control means 41a, and controls at least one of the drive amplitude and the drive time of the vibration device 2 after the next time based on the estimated transport amount Σ. That is, the control unit 41 in the present embodiment is configured to control at least one of the drive amplitude and the drive time of the vibration device 2 based on the integral value of the approximate expression F.

  According to the digital weighing feeder 10 having the above-described configuration, the actual conveyance amount of the object to be weighed is detected by detecting the vibration amplitude a of the digital weighing feeder 10 actually generated and integrating the temporal change of the vibration amplitude a. Since Σ is calculated, the conveyance amount of the object to be weighed can be estimated with high accuracy regardless of the temporal change of vibration in the digital scale feeder 10, and the vibration device 2 of the digital scale feeder 10 can be estimated. Fine drive control can be performed.

  Moreover, since the integration is performed after approximating the temporal change of the vibration amplitude a, the calculation amount of the estimated transport amount Σ can be reduced. Moreover, the vibration device 2 is controlled based on the integral value of the approximate expression F that approximates the temporal change of the vibration amplitude a. For example, in order to halve the transport amount, an integral time such that the integral value of the approximate expression F is halved in the same approximate expression F is set to the driving time of the vibration device 2, or the approximate expression F in the same integral time. Is set to the driving amplitude of the vibration device 2. Thus, the control amount can be easily set using the integral value of the approximate expression F, and the drive control of the vibration device 2 can be easily performed.

  Here, an example of a waveform detected by the strain detection member 3 when the feeder pan 1 that is transporting an object to be weighed is vibrated by a predetermined drive signal will be described. 6 and 7 are graphs showing a comparison between a drive signal and a detected waveform when an object to be weighed is conveyed using the feeder of the present embodiment. FIG. 8 is a graph showing a partially enlarged view of the detected waveform shown in FIG.

  In Example A shown in FIG. 6, the output (piezo output) of the strain detection member 3 when the vibration device 2 is driven with a constant amplitude for a predetermined time while the object to be weighed 400 g is placed on the feeder pan 1. Show. In Example A, the vibration amplitude gradually decreases from the vibration amplitude of the feeder 10 immediately after the start of conveyance of the object to be weighed.

  7 shows the output (piezo output) of the strain detection member 3 when the object to be weighed 400g is supplied onto the feeder pan 1 while the vibration device 2 is driven. In Example B, the vibration component due to the impact of the object to be weighed on the feeder pan 1 is added to the output, and the vibration amplitude of the feeder 10 increases and decreases depending on the driving time.

  Thus, in any example, the vibration amplitude a of the feeder 10 changes with time. In the present embodiment, as described above, the vibration amplitude a of the digital weighing feeder 10 that actually occurs is detected, and the temporal change in the vibration amplitude a is integrated to calculate the estimated transport amount Σ of the object to be weighed. Therefore, the transport amount of the object to be weighed can be estimated with high accuracy regardless of the temporal change of vibration in the digital scale feeder 10, and the drive of the digital scale feeder 10 is finely driven. Control can be performed. In addition, as shown in FIG. 8, the estimated transport amount Σ is calculated by calculating the estimated transport amount Σ using the approximate expression F that draws an approximate curve corresponding to the temporal change of the vibration amplitude a actually obtained. The amount can be reduced.

  In the present embodiment, the control unit 41 functions as the estimated transport weight calculating means 41c, and calculates the estimated transport weight Wk from the estimated transport amount Σ detected using the proportionality coefficient K stored in the storage unit 42 (step) S109). The estimated transport weight Wk obtained by this calculation is stored in the storage unit 42.

  The control unit 41 in the present embodiment performs drive correction processing on the digital weighing feeder 10 based on the estimated transport weight Wk obtained in step S109 (step S110). FIG. 5 is a flowchart showing a control operation in the drive correction process of the digital balance feeder shown in FIG. First, the weight of the weighing object supplied to the corresponding weighing hopper 5 by the digital weighing feeder 10 is measured by the weight sensor 6 (step S201). After the weighing is completed (Yes in step S201), the weight value of the weighed object is stored as the weighing weight W in the storage unit 42 (step S202).

  The control unit 41 calculates the difference between the estimated transport weight Wk and the measured weight W, and determines whether this difference is less than a predetermined allowable value ε (step S203). When the difference is equal to or larger than the allowable value ε (No in step S203), the control unit 41 functions as the correction unit 41d and corrects the proportional coefficient K to K ′ (steps S204 and S205). Specifically, the corrected proportional coefficient K ′ = W / Σ = K · W / Wk is calculated from Wk / K = Σ (step S204), and the corrected proportional coefficient K ′ is set as a new proportional coefficient K. It is stored in the storage unit 42 (step S205).

  The mode of coefficient correction will be described more specifically. Here, a case where the target weight of the object to be weighed held by the weighing hopper 5 is 40 g is illustrated. First, as sample weighing, when the estimated transport amount of the digital weighing feeder 10 becomes Σ = 100, the weighing weight of the object weighed by the corresponding weight hopper 6 becomes W = 40 g. The coefficient K = W / Σ = 0.4 is determined. Using this proportionality coefficient K = 0.4, the weighing operation of the digital scale is started. In this example, the allowable value ε = 0.5 in step S203.

  After the weighing operation is started, when the estimated transport amount of the feeder 10 remains Σ = 100 and the weighing weight of the object weighed by the corresponding weight hopper 6 becomes W ′ = 42 g in a certain weighing cycle, the estimation is performed. Since the transport weight is Wk = K · Σ = 40 g, the difference between the weighed weight W ′ and the estimated transport weight Wk is | W′−Wk | = 2> ε, which exceeds the allowable value ε. Accordingly, the control unit 41 corrects the proportional coefficient K to K ′ = W ′ / Σ = 0.42 (steps S204 and S205). In the next weighing, when the estimated transport amount of the feeder 10 becomes Σ ′ = 95 and the measured weight becomes W ″ = 40.2 g, the estimated transport weight is Wk ′ = K′Σ ′ = 39. Therefore, the difference between the weighed weight W ″ and the estimated transport weight Wk ′ is | W ″ −Wk ′ | = 0.3 <ε, which is within the allowable value ε. The next measurement is performed without correcting K = K ′.

  According to such a configuration, the estimated transport weight Wk obtained by the control unit 41 functioning as the estimated transport weight calculation means 41c is compared with the measured weight W actually measured in the weighing hopper 5, and the estimated transport weight Wk is calculated. In order to correct the proportionality coefficient K that defines the correlation when the deviation from the measured weight W becomes large, the estimated transport weight Wk estimated according to the actual vibration state of the feeder 10 is used as the actual measured weight. W can be easily approached. Therefore, the drive control of the feeder 10 can be performed with higher accuracy. Further, since the correlation between the estimated transport weight Wk and the actual measured weight W is set as a proportional relationship having a proportional coefficient K, the estimated transport weight Wk can be easily calculated, and the proportional coefficient K can be easily corrected. can do.

  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. For example, the calculation method of the estimated transport amount Σ is not limited to the mode of integrating the continuous variables as in the above embodiment, and for example, the temporal change of the vibration amplitude a is detected by dividing it into minute sections, It is good also as an aspect calculated by adding. Specifically, a value obtained by adding the vibration amplitudes a detected in step S104 may be set as the estimated transport amount Σ. Alternatively, for example, the estimated amplitude is obtained by multiplying the vibration amplitude a detected in step S104 by the proportional coefficient K each time, and the sum of the estimated weights is used as the estimated transport amount Σ (that is, the estimated transport weight Wk). It is good to do.

  INDUSTRIAL APPLICABILITY The digital scale feeder of the present invention and the digital scale equipped with the digital scale feeder are useful for a digital scale feeder, a digital scale, and the like that convey an object to be weighed by vibrating a feeder pan on which the object to be weighed is placed by a vibration device It is.

DESCRIPTION OF SYMBOLS 1 Feeder pan 2 Vibration apparatus 3 Strain detection member 4 Control apparatus 5 Weighing hopper 6 Weight sensor (measuring means)
7 Feeding hopper 8 Collecting and discharging unit 9 Operation setting display device 10 Digital scale feeder 11 Main feeder 12 Supply level detector 21 Fixed frame 22 Movable frame 23 Exciter 24 Elastic member 25 Anti-vibration spring 26 Mounting bracket 41 Control unit (control) Means, conveyance amount calculation means, estimated conveyance weight calculation means, correction means)
41a Control means 41b Conveyance amount calculation means 41c Estimated conveyance weight calculation means 41d Correction means 42 Storage part 50 Supply part 51 Weighing hopper gate 71 Supply hopper gate 81 Collecting chute 82 Discharge chute 100 External supply device 111 Top cone 112 Main feeder Exciter

Claims (5)

A feeder pan on which an object to be weighed is placed; a vibration device that vibrates the feeder pan; and a control unit that controls the vibration device. The control unit controls the vibration device to control the vibration device. A digital scale feeder for conveying an object to be weighed,
Amplitude detecting means for detecting the vibration amplitude of the feeder pan generated by the vibration device;
A transport amount calculating means for calculating the estimated transport amount of the object to be measured by integrating the temporal change of the vibration amplitude,
The control means is a digital scale feeder that controls at least one of the drive amplitude and the drive time of the vibration device based on the estimated transport amount. The transport amount calculating means calculates an approximate expression from the temporal change of the vibration amplitude, calculates the estimated transport amount of the object to be measured by integrating the approximate expression,
2. The digital scale feeder according to claim 1, wherein the control unit controls at least one of a drive amplitude and a drive time of the vibration device based on an integral value of the approximate expression. Obtained by a digital scale comprising a weighing hopper that holds and discharges an object to be weighed conveyed by the digital weighing feeder, and a weighing means for detecting the weight of the object to be weighed held by the weighing hopper. Storage means for storing the measured weight of the object to be weighed and storing in advance the correlation between the measured weight and the estimated transport amount;
Estimated transport weight calculating means for calculating an estimated transport weight of an object to be weighed from an estimated transport amount of the object to be weighed using the correlation stored in the storage means;
The digital scale feeder according to claim 1, further comprising: a correction unit that calculates a difference between the estimated transport weight and the measured weight and corrects the correlation when the difference is equal to or greater than a predetermined allowable value. . The correlation is a proportional relationship having a predetermined proportional coefficient,
The digital weighing feeder according to claim 3, wherein the correction unit corrects the proportionality coefficient when the difference is equal to or greater than a predetermined allowable value. A feeder for a digital scale according to claim 3 or 4,
A weighing hopper for holding and discharging an object to be weighed conveyed by the digital weighing feeder;
And a weighing means for detecting the weight of an object to be weighed held by the weighing hopper.

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