JP3834141B2 - Vibratory conveying device for goods - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oscillating conveying apparatus that supplies an article supplied onto a trough by vibrating the trough and supplying a constant weight every predetermined time.
[0002]
[Prior art]
For example, when an article such as a snack is packaged, it is cut out by a combination weighing device. FIG. 9 shows a schematic side view of the mechanism portion of the combination weighing device. The article M is supplied to the center of the short conical dispersion feeder 41 via the supply chute 40. Then, the vibration is distributed and supplied to the plurality of vibration feeders 1 arranged radially by the vibration of the dispersion feeder 41. Next, the articles M are conveyed to the respective vibration feeders 1 and sent to the pool hoppers 42 arranged on the circumference. After the articles M are temporarily pooled in accordance with the weighing operation, the discharge gate 43 of the pool hopper 42 is opened. It is opened and put into the weighing hopper 44. The weighing means 45 such as a load cell measures the weight W of the article M pooled in each weighing hopper 44 and outputs a weighing signal. The articles M weighed in weight W are collected by the collecting chute 47 with the discharge gate 46 of the weighing hopper 44 opened, and discharged to the discharge chute 48. The discharged article M is packaged by a packaging machine (not shown) to become a packaged product with a target weight. An input target value is set in each weighing hopper 44, and the amplitude or vibration time of the vibration feeder 1 is adjusted according to the magnitude of the measured value with respect to the target value so that the measured value matches the input target value. I have control.
[0003]
[Problems to be solved by the invention]
However, this control is performed by reading the measurement value of the weighing hopper, that is, the measurement value downstream of the conveying device, and is not performed by accurately reading the conveyance amount of the vibration feeder in real time. Delay increases and response is poor. For this reason, it is difficult to accurately control the input amount (conveyance amount).
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems and to provide a vibration type conveying apparatus that can accurately control the conveyance amount in real time.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a vibration conveying apparatus for an article according to one configuration of the present invention is a conveying apparatus that vibrates a trough and conveys an article loaded on the trough in a vibration direction. A strain gauge is provided in a spring member that connects the two, and the weight of the article loaded on the trough and the amplitude of the trough are detected based on the electrical output of the strain gauge, and from the detected weight and amplitude The transport amount per unit time is calculated in real time, and the transport device is controlled based on the transport amount.
According to the above configuration, the weight of the article loaded on the trough and the amplitude of the trough are detected from the strain amount of the strain gauge provided on the spring member, and the conveyance amount of the article is calculated in real time from this weight and amplitude. , and controls the oscillation frequency of the transport device, the amplitude, the operation time on the basis of the conveyance amount, it is possible to perform accurate control of the transport apparatus.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
FIG. 1 shows a schematic side view of the vibration feeder. The vibration feeder 1 includes a vibrator 2 and a trough 4 attached to the vibrator 2 via a bracket 3. The vibration exciter 2 includes a base 7 attached to a mount 5 to which the vibration feeder 1 is attached via a plurality of rubber or coil spring elastic or vibration isolating elastic bodies 6, The electromagnet 8 attached to the base 7 and one end 9a are attached to the front and rear parts of the base 7 by bolts B1, and the other end 9b is attached to the bracket 3 by bolts B2 and arranged in parallel. A pair of leaf springs 9 and a movable iron core 10 fixed to the bracket 3 and facing the electromagnet 8. The movable iron core 10 is fixed to the bracket 3 at a position corresponding to the other end portion 9 b of one leaf spring 9. The electromagnet 8 is supplied with power from a commercial AC power supply 11 via a switching element 12.
[0012]
The switching element 12 supplies the electromagnet 8 with an AC drive current having a frequency fd and a current amount Id based on the drive control signal Cd output from the controller 13, and attracts the movable iron core 10 of the electromagnet 8 and the spring of the leaf spring 9. With the amplitude A determined by the constant k, the trough 4 is vibrated in the direction of arrow V while keeping the horizontal posture, and the article M on the trough 4 is conveyed in the direction of arrow P (horizontal direction). The resonance frequency fn of the vibration system configured as described above is obtained by the following equation.
fn = (1 / 2π) (k / m) ^1/2
Where m = (m1 × m2) / (m1 + m2), k is the spring constant, m1 is the sprung weight, and m2 is the unsprung weight.
In the present embodiment, the resonance frequency fn is set to be a frequency close to the commercial power supply frequency, whereby the amplitude of the trough 4 is increased with low power.
[0013]
Four strain gauges 14 a to 14 d are mounted in the vicinity of the bracket 3 at both ends of the leaf spring 9 on the front side in the transport direction and the fixing portion to the base 7. The mounting portion U is a portion where the elastic strain of the leaf spring 9 is large during vibration. That is, since the pair of leaf springs 9, 9 and the bracket 3 and the base 7 constitute a kind of Roverval mechanism that deforms while maintaining the parallelogram shape, the leaf spring 9 has one end 9a as a fulcrum. When the other end portion 9b moves, the vicinity of the bolts B1, B2, that is, the vicinity of the fixed portion is bent, and a large elastic strain is generated in this portion. The strain amounts detected by the strain gauges 14a to 14d are input to the weight detection circuit 15 in FIG. 1, and known device weights such as the bracket 3, trough 4, and movable iron core 10 are subtracted as a tare, and the trough 4 The weight of the article M is detected. As described above, the strain gauges 14 a to 14 d and the weight detection circuit 15 constitute a weight detector 23.
[0014]
FIG. 2 is a front view showing the arrangement positions of the strain gauges 14 a to 14 d of the leaf spring 9. The leaf spring 9 is rectangular, and an attachment hole H1 for attachment to the base 7 is formed at one end portion 9a in the longitudinal direction, and an attachment hole H2 for attachment to the bracket 3 is formed at the other end portion 9b. The bolts B1 and B2 are inserted into the mounting holes H1 and H2. The strain gauges 14a and 14c are attached in the vicinity of the attachment hole H2, and the strain gauges 14b and 14d are attached in the vicinity of the attachment hole H1 with an adhesive at a position closer to the center of the leaf spring 9 than the respective fixed portions. The output leads are connected to the four wires 16a to 16d of the flexible wiring sheet 16 to constitute the bridge circuit 17 shown in FIG.
[0015]
FIG. 3 is a diagram showing the configuration of the bridge circuit 17 and the weight detection circuit 15. The weight detection circuit 15 includes first to fourth integrators 19 a to 19 d, first and second voltage dividers 20 and 21, and a signal processing circuit 22. The connection point c between the strain gauges 14a and 14c of the bridge circuit 17 is connected to the DC constant voltage power source 18, and the connection point d between the strain gauges 14b and 14d is grounded. The connection point a between the strain gauges 14a and 14b is connected to the first integrator 19a, and the connection point b between the strain gauges 14c and 14d is connected to the second integrator 19b. On the other hand, between the connection point c and the ground, a first voltage divider 20 constituted by a series body of resistors R1 and R2 and a second voltage divider constituted by a series body of resistors R3 and R4. The output voltage of the first voltage divider 20 is input to the third integrator 19c, and the output voltage of the second voltage divider 21 is input to the fourth integrator 19d. The signal processing circuit 22 has a voltage VC at the connection point c, a ground potential at the connection point d, output voltages Va and Vb from the integrators 19a and 19b, a common voltage Vcom from the integrator 19c, and a reference voltage Vref from the integrator 19d. The weight W on the trough 4 is calculated. That is, the weight W is obtained as an average value of the vibrating weight signal obtained by the bridge circuit 17.
[0016]
FIG. 4 is a diagram illustrating the vibration characteristics of the vibration system of the trough 4 in the present embodiment. This vibration system includes a vibrator 2, a bracket 3, a gantry 5, and an elastic body 6. The resonance frequency fn is determined by the spring constant k of the leaf spring 9 and the unsprung weight m1 and unsprung weight m2 as described above. Therefore, the resonance frequency fn varies depending on the weight W of the article M on the trough 4, and is shown in FIG. Thus, when the weight W changes from W1 to a large value W2, it decreases as fn1 to fn2. On the other hand, the amplitude A of the leaf spring 9 varies depending on the magnitude of the drive current Id and its frequency fd, and increases as the drive current Id increases and the drive frequency fd approaches the resonance frequency fn. Therefore, for example, even if the drive current Id and its frequency fd1 are the same, when the weight W changes from W1 to W2, the amplitude changes from A1 to A2.
[0017]
As a result of examination by the inventors, it was found that the conveyance amount of the vibration feeder 1 is determined by (weight W of the article on the trough) × (amplitude A of the leaf spring) × (vibration time T) × (coefficient). Therefore, the conveyance amount can be adjusted by adjusting any of the values, and the conveyance amount per unit time can be adjusted by adjusting the weight W of the article on the trough or the amplitude A of the leaf spring. . The coefficient is used to correct an angular deviation between the vibration direction V of the leaf spring 9 and the conveying direction P of the trough 4, a difference in slip depending on the type of article, and the like, and is obtained empirically. Note that the amplitude of the trough 4 in the conveying direction P may be regarded as the amplitude of the leaf spring 9, and in this case, the value of the coefficient is different.
[0018]
The amplitude detection means 25 in FIG. 1 detects the amplitude A in the conveying direction of the trough 4 from the strain amount of the strain gauge 9. Further, the data storage means 24 stores data of the drive frequency fd of the vibrator 2 and the amplitude A of the leaf spring 9 using the weight W of the article on the trough 4 as a parameter. This data is obtained, for example, by actually driving and conveying the vibration feeder 1 and obtaining the weight W of the article at that time by the above method and obtaining the amplitude A from the strain amount of the strain gauges 14a to 14d. It is done. The amplitude detector 25 reads out the amplitude A corresponding to the weight W of the article detected by the weight detector 23 and the drive frequency fd from the data storage 24 and outputs it.
[0019]
Next, the conveyance amount calculation unit 26 detects the amplitude A input from the amplitude detection unit 25, the weight W of the article input from the weight detector 23, and the amplitude detection unit 25 or from the controller 13. The transport amount Sw is calculated based on the transport time (operation time of the vibrator 2) T obtained from the duration of the output control signal Cd. The carry amount control means 27 outputs to the controller 13 a carry amount control signal Csw for correcting the difference between the inputted carry amount Sw and the target carry amount by adjusting the amplitude A or the carry time T. The controller 13 controls the amplitude A to become the commanded amplitude by adjusting the firing angle of the switching element 12 to adjust the drive current Id, or the operation time T of the vibrator 2 is instructed. To control the time. For example, in FIG. 4, when the drive frequency is fd1 and the weight is W1, if the drive current Id is increased, the vibration characteristic curve becomes a shape indicated by a broken line upward, and the amplitude A increases as A3. . When the weight changes from W1 to a large value W2, the resonance frequency decreases from fn1 to fn2, and the amplitude A decreases from A1 to A2.
[0020]
According to the present embodiment, the weight W of the article on the trough 4 is directly detected, and the transport amount Sw can be obtained accurately in real time. Further, since the transport amount of the vibration feeder 1 is controlled based on the transport amount Sw obtained in real time, the response is excellent, and therefore, highly accurate control is performed. Further, since the weight W of the article is detected using the strain gauges 14a to 14d attached to the leaf spring 9, and a separate load cell is not required, the configuration is small and simple. Further, since the data storage means 24 stores the data indicating the relationship between the drive frequency fd and the amplitude A using the weight W of the article on the trough 4 as a parameter, the first measurement at the start of the operation of the vibratory conveyance device. The conveyance amount can be adjusted from the data. For this reason, there is no need for test operation, and the operating rate can be increased.
[0021]
FIG. 5 is a diagram showing a second embodiment of the present invention. The same reference numerals as those in FIG. 1 denote the same or corresponding parts, respectively. In the present embodiment, the weight detector 23 includes a load cell 30 and a weight detection circuit 15. The load cell 30 of the present embodiment has a fixed side supported by a gantry 5 via a support member 31, and a holding gantry 50 is attached to a movable side via a support member 32, and the vibration feeder 1 supported by the gantry 5. It is configured to weigh the total weight. Other configurations and operations thereof are the same as those in the first embodiment, and a description thereof will be omitted.
[0022]
Also according to the present embodiment, the transport amount Sw can be obtained with high accuracy in real time, high-accuracy transport amount control with excellent responsiveness can be performed, and further, the operation rate can be increased without the need for trial operation. it can.
[0023]
The third embodiment of the present invention has the same apparatus configuration as that of the first embodiment shown in FIG. 1, and obtains the weight of the article on the trough 4 based on the amplitude-weight characteristic shown in FIG. That is, when the drive frequency fd of the vibrator 2 is constant and the variation in the weight W of the article M is not so large, there is no big error even if the amplitude A is uniquely determined from the weight W. Therefore, an amplitude-weight characteristic as shown in FIG. 6 is obtained, stored in the data storage means 24 of FIG. 1, and based on the weight W detected by the weight detector 23, the amplitude A is obtained from the stored characteristic data. Ask for. Using the weight W and the amplitude A thus obtained, the carry amount calculating means 26 calculates the carry amount Sw, and the carry amount control means 27 outputs a carry amount control signal Csw.
[0024]
FIG. 7 shows a vibration type conveying apparatus according to a fourth embodiment for obtaining the amplitude of a leaf spring in addition to the weight of an article by using a strain gauge. The same reference numerals as those in FIG. 1 denote the same or corresponding parts, respectively. . In FIG. 7, reference numeral 14 denotes a strain gauge, which is attached to a portion where the amount of bending during vibration of the leaf spring 9 is large. In the first embodiment, four strain gauges are arranged in the leaf spring to form a bridge circuit to compensate for measurement errors due to temperature compensation, torsion, etc., but if high measurement accuracy is not required, one strain gauge is used. A gauge is arranged in a portion where the strain amount of the leaf spring is large, and both the weight W of the article on the trough and the amplitude A of the leaf spring 9 are detected from the strain amount of the leaf spring 9 detected by the strain gauge 14. be able to.
[0025]
In FIG. 7, reference numeral 33 denotes an amplitude detector, which includes a strain gauge 14 and an amplitude detection circuit 33, and the amplitude detection circuit 33 detects the amplitude A of the leaf spring 9 from the amount of strain that the strain gauge 14 vibrates. The strain amount of the vibration of the strain gauge 14 corresponds to the deformation amount of the leaf spring 9. The operations of the weight detector 23, the carry amount calculation means 26, and the carry amount control means 27 are the same as those in the first embodiment, and thus the description thereof is omitted.
[0026]
According to the fourth embodiment, in addition to obtaining the same effect as the first embodiment, the configuration is further simplified because the data storage means provided in the first embodiment is not required. Also in this embodiment, the weight detector 23 can be a load cell type similar to that of the second embodiment.
[0027]
The means for detecting the trough amplitude (plate spring amplitude) is not limited to that detected by the strain gauge, and may be an optical detection means or an electrical detection means.
[0028]
FIG. 8 shows the configuration of a vibratory transfer device according to the fifth embodiment of the present invention. In the present embodiment, the weight of the article on the trough 4 is obtained based on the amplitude-weight characteristic shown in FIG. 6 from the amplitude value detected by the amplitude detector 33 shown in FIG. That is, the data storage means 24 stores the relationship between the amplitude value A of the leaf spring 9 shown in FIG. 6 and the weight W of the article on the trough 4, and the carry amount calculating means 26 is an amplitude detector 33. The weight W corresponding to the detected amplitude A is read from the data storage means 24, and the carry amount Sw is calculated. The carry amount control means 27 compares the inputted carry amount with the target carry amount, and when the difference exceeds the allowable range, reads the amplitude value A that becomes the target carry amount from the data storage means 24 and applies vibration. A transport amount control signal Csw for changing the current Id of the container 2 to a drive current Id with the amplitude of the leaf spring 9 being A1 is sent to the controller 13. According to this embodiment, the weight detector can be omitted.
[0029]
The sixth embodiment of the present invention is provided with data storage means 24 for storing a plurality of amplitude-driving frequency characteristics respectively corresponding to a plurality of weights W of articles on the trough 4 shown in FIG. 4 in the configuration shown in FIG. Then, the transport amount calculating means 26 calculates the weight W of the article on the trough 4 from the amplitude value A detected by the amplitude detector 33 and the drive frequency fd. The control operation of the drive current Id by the carry amount control means 27 is the same as that in the fifth embodiment. According to the sixth embodiment, the weight detector can be omitted, and the transport device can be controlled with higher accuracy.
[0032]
【The invention's effect】
According to one configuration of the present invention, the weight of the article on the trough and the amplitude of the trough are detected from the strain amount of the strain gauge provided on the spring member, and the conveyance amount of the article is calculated in real time from this weight and amplitude. and, since the control vibration frequency of the carrier device, the amplitude, the operation time on the basis of the conveyance amount, it is possible to perform accurate control of the transport apparatus.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a vibration type conveying apparatus according to a first embodiment of the present invention.
FIG. 2 is a front view showing an arrangement position of a strain gauge of the leaf spring of the first embodiment.
FIG. 3 is a diagram illustrating a configuration of a bridge circuit and a weight detection circuit according to the first embodiment.
FIG. 4 is a characteristic diagram showing the relationship between the vibration frequency of the vibration system of the first embodiment and the amplitude of the trough in the carrying direction.
FIG. 5 is a diagram showing a configuration of a vibratory transfer device according to a second embodiment of the present invention.
FIG. 6 is a diagram showing weight-amplitude characteristics stored in data storage means of a third embodiment of the present invention.
FIG. 7 is a diagram showing a configuration of a vibration type conveying apparatus according to a fourth embodiment of the present invention.
FIG. 8 is a diagram showing a configuration of a vibratory transfer device according to a fifth embodiment of the present invention.
FIG. 9 is a schematic side view of a mechanism unit of the combination weighing device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vibration feeder, 2 ... Exciter, 3 ... Bracket, 4 ... Trough, 5 ... Mount, 6 ... Elastic body for vibration suppression, 7 ... Base, 8 ... Electromagnet, 9 ... Leaf spring, 10 ... Movable iron core,
11 ... Commercial power supply, 12 ... Switching element, 13 ... Controller,
14a-14d ... strain gauge, 15 ... weight detection circuit, 16 ... flexible wiring sheet, 16a-16d ... wiring, 17 ... bridge circuit, 18 ... DC constant voltage power supply,
19a to 19d ... integrator, 20, 21 ... voltage divider, 22 ... signal processing circuit, 23 ... weight detector, 24 ... data storage means, 25 ... amplitude detection means, 26 ... carry amount calculation means, 27 ... carry amount control Means 30 ... Load cell 31, 32 ... Supporting member 33 ... Amplitude detector 34 ... Amplitude detection circuit 40 ... Supply chute 41 Dispersion feeder 42 ... Pool hopper 43, 46 Discharge gate 44 ... Weighing hopper 45 ... measuring means, 47 ... collecting chute, 48 ... discharge chute, A ... plate spring amplitude, AA ... plate spring detected amplitude value, Cd ... drive control signal, Csw ... conveyance amount control signal, fd ... drive frequency, Id: drive current, M: article, Sw: transport amount, T: transport time, W: weight of the article.

Claims (1)

A conveying device that vibrates a trough to convey an article loaded on a trough in a vibration direction,
A strain gauge is provided on a spring member connecting the trough and the base, and the weight of the article loaded on the trough and the amplitude of the trough are detected based on the electrical output of the strain gauge, and the detected weight A vibration conveying device for an article, which calculates a conveyance amount per unit time in real time from the amplitude and amplitude, and controls the conveyance device based on the conveyance amount.

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