JP3881608B2 - Electromagnetic feeder and weighing device equipped with the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic feeder that conveys an article by vibrating a trough by an electromagnetic force generated intermittently by an electromagnet, and a weighing device including the electromagnetic feeder, and belongs to the technical field of article conveyance.
[0002]
[Prior art]
In a weighing device or the like, for example, an electromagnetic feeder is provided to transfer the supplied article to a weighing hopper or the like. The electromagnetic feeder includes, for example, a trough attached to the base member via a pair of front and rear spring bodies, an electromagnet installed on the base member, and an energization control unit that energizes the electromagnet intermittently during a normal conveyance period. The electromagnetic force is intermittently generated by the electromagnet, and the trough is displaced to one side while the spring body is bent when the electromagnet is generated, and the trough is caused by the elastic restoring force of the spring body when the electromagnet is not generated. By displacing to the other side, the trough is vibrated to transfer articles on the trough in a predetermined direction.
[0003]
In order to improve the weighing accuracy in, for example, a combination weighing device provided with a plurality of electromagnetic feeders of this type, it is necessary to improve the accuracy of the amount of articles supplied from the electromagnetic feeder to the weighing hopper. Sometimes, simply stopping energization of the electromagnet will only naturally attenuate the trough amplitude, so that the vibration will continue for a while and the article will continue to be conveyed. That is, the substantial supply period of the article becomes longer, the article supply amount becomes larger than the target amount, and the measurement accuracy is lowered. And in the case where the target amount of the article to be the product is determined, this is important not only for the combination weighing device but generally for the weighing device.
[0004]
In order to prevent this, it is necessary to stop the supply of goods by quickly stopping the vibration after the end of the normal conveyance period. Therefore, for example, by setting the phase of the drive signal to be opposite to the original phase at the end of the conveyance period in which the phase of the trough vibration and the phase of the drive signal (electric power) are in resonance with each other in resonance. In addition, a force having a phase substantially opposite to the phase of the current amplitude is applied to the vibrating trough so as to quickly attenuate the vibration (see, for example, Patent Document 1). According to this, after the end of the normal conveyance period, the trough amplitude is quickly attenuated and the article conveyance is stopped.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-263317 (page 2-6, FIG. 10)
[0006]
[Problems to be solved by the invention]
However, when the normal transport period is short, the phase of the drive signal and the phase of the amplitude do not reach the same phase at the end of the period even though the amplitude has increased to near the predetermined amplitude due to forced vibration. There is. That is, even if the phase is opposite to that of the original driving signal, the vibration is not effectively attenuated because the phase is not opposite to the amplitude. Further, depending on how the phase of the drive signal is shifted from the phase of the amplitude, the change in the phase of the drive signal may act in the direction of exciting the trough.
[0007]
Accordingly, the present invention provides an electromagnetic feeder capable of quickly stopping the trough vibration immediately after the end of the transport period, regardless of the length of the normal transport period, and a weighing device including the electromagnetic feeder. Is an issue.
[0008]
[Means for Solving the Problems]
The inventor of the present invention has conducted extensive research and experiments to solve the above problems, and as a result, the relationship between the phase of the amplitude of the electromagnetic feeder and the phase of the drive signal at the end of the normal transport period is the time of the transport period. In order to quickly reduce the trough vibration after the end of the transport period, it has been found that it is effective to energize in a pattern according to the time of the normal transport period. The present invention has been reached.
[0009]
That is, in order to solve the above-mentioned problem, the present invention is configured as follows.
[0010]
First, the invention according to claim 1 of the present application is an electromagnetic feeder that conveys an article by vibrating a trough by intermittently energizing an electromagnet, and uses an intermittent energization pattern different from a normal conveyance period as a stop pattern. A plurality of storage means for storing, a pattern setting means for setting a pattern in which convergence of trough vibration is accelerated among the plurality of stop patterns stored in the storage means according to the time of the normal transport period; and the pattern There is provided an energization control means for controlling energization after the end of the conveyance period with the stop pattern set by the setting means.
[0011]
According to this invention, the electromagnetic feeder is energized with a stop pattern set as a pattern in which the convergence of trough vibration is accelerated among a plurality of stop patterns according to the time of the normal transport period after the end of the normal transport period. Regardless of the length of time, the trough vibrations are quickly damped and stopped. As a result, the accuracy of the amount of articles supplied by the electromagnetic feeder is improved.
[0012]
The pattern setting means may set the stop pattern automatically or manually. That is, in the case of automatic setting, the pattern setting means automatically detects the time of the transport period set by, for example, the transport period setting means for setting the time of the transport period, and is associated in advance with the time of the transport period. In the case of manual setting, the stop pattern is automatically read out from the storage means, and in the case of manual setting, the pattern setting means is a stop manually selected from the stop patterns stored in the storage means, for example, by an operator A pattern is set.
[0013]
Next, the invention according to claim 2 of the present application is characterized in that, in the invention according to claim 1, the plurality of stop patterns differ in at least the period of intermittent energization.
[0014]
According to the present invention, it is possible to generate a vibration having a period suitable for quickly converging the vibration after the end of the period according to the time of the normal conveyance period. In other words, vibrations with different periods can be generated according to the relationship between the amplitude phase and the intermittent energization phase at the end of the normal conveyance period, and can act as a brake against the vibrating trough.
[0015]
Next, the invention according to claim 3 of the present application is characterized in that, in the invention according to claim 1 or 2, the plurality of stop patterns differ in at least intermittent energization ON times.
[0016]
According to the present invention, vibration can be generated for a time suitable for quickly converging vibration after the end of the normal conveyance period. Further, if implemented together with the change of the period of claim 2, the vibration of the trough can be attenuated more rapidly.
[0017]
In addition, the invention according to claim 4 of the present application is provided with the electromagnetic feeder according to any one of claims 1 to 3 and a weighing unit for weighing an article conveyed from the electromagnetic feeder. It is characterized by being.
[0018]
According to this invention, the accuracy of the amount of articles supplied from the electromagnetic feeder to the weighing means of the weighing device is improved, and the weighing accuracy of the weighing device is improved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0020]
FIG. 1 shows a schematic configuration of a combination weighing device 2 including an electromagnetic feeder 1 according to the first embodiment. The combination weighing device 2 includes a dispersion table 6 installed in the center of the machine base 3 via a vibration exciter 4 and disperses an object to be weighed dropped from an upper cylindrical charging chute 5 around it, A plurality of troughs 8... 8 that are radially arranged around the peripheries via the vibrators 7... 7 to convey the objects to be weighed, and circular so as to be respectively positioned below the tips of these troughs 8. There are provided a plurality of pool hoppers 9 ... 9 and weighing hoppers 10 ... 10 arranged below the respective pool hoppers 9 ... 9. Here, the electromagnetic feeder 1 includes the vibrator 7 and the trough 8.
[0021]
In the machine base 3, gate opening / closing devices 11 ... 11 for controlling the opening / closing of the gates 9a ... 9a of the pool hoppers 9 ... 9 and the gates 10a ... 10a of the weighing hoppers 10 ... 10 are arranged. Yes. This gate opening / closing device 11 is driven by a motor (not shown), and when receiving a weighing object discharge command, the weighing object in the weighing hopper 10 is discharged into the collecting chute 12 by a driving means (not shown), The operation is performed so that the objects to be weighed in the pool hopper 9 are put into the weighing hopper 10 which has become empty. In addition, a weight detector (not shown) is connected to the weighing hopper 10 in the machine base 3 to measure the weight of an object to be weighed in the weighing hopper 10.
[0022]
As shown in FIG. 2, the vibrator 7 of the electromagnetic feeder 1 is installed on the base 3 via a plurality of coil springs 21... 21, and on the upper surface of the base member 22. And a pair of parallel leaf springs 25 and 25 attached to the front side (the left side in the drawing) and the rear side (the right side in the drawing) of the base member 22 by bolts 24. A bracket 8a of the trough 8 is fixed to the upper portions of the two leaf springs 25, 25 with bolts 26. A magnetic body 27 is attached to a surface of the bracket 8a that faces the magnetic force generation surface 23a of the electromagnet 23. The electromagnet 23 is intermittently energized via a feeder control device 30 described later (see FIG. 3).
[0023]
According to this, when the electromagnet 23 is energized, an electromagnetic force (attraction) acts between the magnetic force generating surface 23a and the magnetic body 27. As a result, the front and rear leaf springs 25 ... 25 are bent, At the same time, the trough 8 is displaced slightly forward (to the left side of the drawing) while slightly sinking. On the other hand, when the energization to the electromagnet 23 is stopped, the electromagnetic force (attraction) between the magnetic force generating surface 23a and the magnetic body 27 disappears, and the trough 8 is caused by the elastic restoring force of the leaf springs 25 ... 25. It will be displaced backward (to the right side of the drawing) while slightly rising upward. That is, if the electromagnet 23 is energized intermittently, electromagnetic force is intermittently generated and the trough 8 vibrates in the front-rear direction.
[0024]
FIG. 3 is a block diagram illustrating a configuration of a feeder control device 30 that controls energization to the electromagnet 23 of the electromagnetic feeder 1. The control device 30 includes a transfer period setting means 31 for setting the normal transfer period according to the type and the transfer amount of the article, and the DC power source A is connected to the electromagnet 23 in a conductive state while the control pulse is applied. A switching element 32 such as an FET (field effect transistor) that supplies current to the gate, pulse generation means 33 that applies a control pulse to the gate of the switching element 32, and a pulse generation pattern such as a generation period and a pulse width of the control pulse And a combination pattern measuring device 2 that selects and reads out the corresponding pattern from the generated pattern storage unit 34 based on the transport period time set by the transport period setting unit 31. Each time a feeder drive signal output from the controller B of the receiver is received, a pulse is generated according to the read pulse generation pattern And a control unit 35 for delivering a pulse generating signal for forming means 33. Here, the pulse generation means 33 has a pulse counter that counts the number of pulses generated after receiving the feeder drive signal, and the number of pulses counted by the pulse counter is a predetermined pulse defined in the pulse generation pattern. Generate control pulses until the number is reached.
[0025]
According to this, as shown in FIG. 4, when a feeder drive signal is output from the controller B of the combination weighing device 2 to the control unit 35, a pulse is generated based on the pulse generation pattern read from the pulse generation pattern storage unit 34. The generated signal is sent to the pulse generating means 33, and the control pulse is applied to the gate of the switching element 32 by the pulse generating means 33. Then, during the period when the control pulse is applied, the switching element 32 is conducted and a voltage is applied to the electromagnet, and the electromagnetic force is intermittently generated, and the trough 8 vibrates. Here, the generation period of the control pulse is set to the value thereof or a value close thereto in consideration of the resonance period of the vibration system of the electromagnetic feeder device 1, and the trough 8 is configured to vibrate efficiently.
[0026]
In this case, as shown in FIG. 5, the generation pattern storage unit 34 stores three types of patterns as control pulse generation patterns generated during the normal transfer period and after the end of the transfer period. The generation period and pulse width of the control pulse during the normal transfer period are the same in all patterns, but the number of control pulses, the generation period, and the pulse width pattern given after the end of the transfer period are different. Here, the purpose of generating the control pulse after the end of the conveyance period is to quickly stop the trough vibration. That is, three types of stop patterns are prepared for trough stop. Here, the display of the period and the pulse width is 12/16, 8/8, etc., but this is the value of the period and the pulse width during the normal conveyance period 16/16, 8/8 (that is, both are 1). ) Is a relative value when used as a reference. Here, the real cycle in this embodiment corresponding to this cycle 16/16 is 25 ms. For example, when the cycle is 12/16, the real cycle in this embodiment is obtained by multiplying 25 by 12/16. .75 ms.
[0027]
First, pattern 1 gives a control pulse three times after the end of the normal conveyance period, and the period and pulse width are 10/16 and 10/8 for the first time, 16/16 and 10/8 for the second time, The third is 12/16 and 8/8. Pattern 2 gives control pulses twice after the end of the normal conveyance period, and the period and pulse width are 10/16 and 10/8 for the first time and 18/16 and 10/8 for the second time. Pattern 3 gives control pulses twice after the end of the normal conveyance period, and the period and pulse width are 12/16 and 8/8 for the first time and 16/16 and 10/8 for the second time.
[0028]
FIG. 6 shows, by experiment, which of the three types of patterns has an effect of quickly attenuating the trough amplitude after the end of the normal transport period when the time of the normal transport period is changed. From this result, the pattern 1 is obtained when the normal conveyance period is 1 to 320 ms (conveyance condition 1), and the pattern is obtained when the normal conveyance period is 321 to 600 ms (conveyance condition 2). 2 and when the time of the normal transport period is 601 ms or more (transport condition 3), it can be seen that pattern 3 is effective.
[0029]
Therefore, in the present embodiment, when the time of the normal transport period set by the transport period setting unit 31 matches the transport condition 1 (transport period time: 1-320 ms), the transport is performed based on the pattern 1. When the time of the period matches the transport condition 2 (transport period time: 321 to 600 ms) When the time of the transport period matches the transport condition 3 (transport time: 601 ms or more) based on the pattern 2 Is configured so that the pulse generating means 34 generates a control pulse based on the pattern 3.
[0030]
Next, the results when the electromagnetic feeder 1 according to the present embodiment is driven under the three conveyance conditions will be described in more detail.
[0031]
FIG. 4 shows a case where the control pulse of pattern 1 is generated in the case of the transport condition 1. That is, during the normal transport period tc1, a control pulse X0 having a pulse width of 8/8 is applied 8 times with a period of 16/16 (corresponding to an actual period of 25 ms as described above), and after the end of the transport period tc1, the trough 8 Control pulses X1, X2, and X3 corresponding to the first to third pulses of the pattern 1 shown in FIG. 5 are applied. Here, in the present embodiment, the time of the normal transport period is defined as a value obtained by subtracting 15 ms from a value obtained by multiplying the control pulse generation period by the number of control pulses generated during the transport period. According to this definition, the time of the normal transport period tc1 in the case of the transport condition 1 is 25 ms × 8−15 = 185 ms.
[0032]
In the case of the transport condition 1, the trough 8 is forcibly vibrated by the control pulse (electromagnet drive voltage) in the initial stage during the normal transport period tc1, and the amplitude increases sharply from the fourth pulse. It is a great increase. On the other hand, during the transport period tc1, as shown by the symbol Q, the rising edge of the driving voltage and the rising edge of the amplitude have not been matched yet, that is, the phase of the amplitude and the phase of the driving voltage are not matched. I'm on my way. Here, the coincidence state is a state in which the drive voltage rise and amplitude rise timing indicated by S in FIG. 8 described later coincide, that is, the drive voltage phase and the amplitude phase coincide. This is a state that can be said to be a resonance state. In the case of FIG. 6, it can be said that it is in a non-resonant state.
[0033]
When the drive voltage corresponding to the control pulses X1, X2, and X3 of the pattern 1 is sequentially applied to the electromagnet 23 after the end of the normal transport period tc1, the amplitude is rapidly reduced to about 1/3. That is, even if the trough 8 is in a non-resonant state at the end of the normal conveyance period tc1, the amplitude of the trough 8 can be quickly attenuated by applying the drive voltage corresponding to the pattern 1 to the electromagnet 23.
[0034]
FIG. 7 shows a case where the control pulse of the pattern 2 is generated in the case of the transport condition 2. That is, the control pulse X0 is applied 14 times during the normal transport period tc2, and after the end of the transport period tc2, the first and second pulses of the pattern 2 shown in FIG. Control pulses X11 and X12 are applied. Here, according to the above definition, the time of the normal transport period tc2 in the case of the transport condition 2 is 335 ms.
[0035]
In the case of the transport condition 2, the normal transport period is longer than the transport condition 1, and the amplitude thereof is substantially constant. On the other hand, at the end of the normal transport period tc2, as shown by the symbol R, the vibration state proceeds to a state where the rise of the drive voltage and the rise of the amplitude are slightly shifted, that is, a state immediately before resonance.
[0036]
When the drive voltage corresponding to the control pulses X11 and X12 of the pattern 2 is sequentially applied to the electromagnet 23 after the end of the normal transport period tc2, the amplitude is rapidly reduced to about 1/3. That is, even when the trough 8 is in a state immediately before resonance at the end of the normal transport period tc2, the drive voltage corresponding to the pattern 2 is applied to the electromagnet 23 so that the amplitude of the trough 8 is quickly converged and attenuated. be able to.
[0037]
FIG. 8 shows a case where the control pulse of pattern 3 is generated in the case of the conveyance condition 3. That is, during the normal transport period tc3, the control pulse X0 is applied 50 times, and after the end of the transport period tc3, it corresponds to the first and second pulses of the pattern 3 shown in FIG. Control pulses X21 and X22 are applied. Here, the length of the normal transport period tc3 in the case of the transport condition 3 is 1235 ms according to the above definition.
[0038]
In the case of the transport condition 3, the normal transport period is longer than the transport condition 2, and the amplitude thereof is almost constant. On the other hand, at the end of the normal transport period tc3, as shown by the symbol S, the rising edge of the driving signal and the rising edge of the amplitude coincide, and the phase of the driving signal and the phase of the amplitude coincide, that is, a resonance state is reached. .
[0039]
When the drive voltage corresponding to the control pulses X21 and X22 of the pattern 3 is sequentially applied to the electromagnet 23 after the end of the normal transport period tc3, the amplitude is rapidly reduced to about 1/3. That is, even when the trough 8 is in a resonance state at the end of the normal transport period tc3, the driving voltage corresponding to the pattern 2 can be applied to the electromagnet 23 to quickly converge and attenuate the trough 8 amplitude. .
[0040]
As described above, by energizing the electromagnet 23 in a pattern according to the transport conditions after the end of the normal transport period, the vibration of the trough 8 is quickly attenuated regardless of the length of the normal transport period. Become.
[0041]
In addition, since the plurality of stop patterns have different periods of intermittent energization, it is possible to generate a vibration having a period suitable for quickly converging the vibration after the end of the period according to the time of the normal conveyance period. In other words, vibrations with different periods can be generated according to the relationship between the amplitude phase and the intermittent energization phase at the end of the normal conveyance period, and can act as a brake against the vibrating trough.
[0042]
Further, since the plurality of stop patterns have different intermittent energization ON times, the vibrations can be generated for a time suitable for quickly converging the vibration after the end of the normal conveyance period.
[0043]
In the present embodiment, both the change of the control pulse generation period and the increase of the pulse width (ON time of intermittent energization) are performed. It will act longer and the amplitude of the trough 8 will decay more quickly.
[0044]
In that case, when the normal transport period is long, the final attenuation effect is improved by delaying the application of the first control pulse after the end of the transport period, compared to when the normal transport period is short. It was found from FIGS. 5 and 6 that a damping effect can be obtained.
[0045]
Further, in the combination weighing device 2 provided with the electromagnetic feeder 1, the accuracy of the amount of articles supplied from the electromagnetic feeder 1 to the weighing hopper 10 is improved, and the weighing accuracy is improved.
[0046]
In the present embodiment, the case where the driving frequency (control pulse generation period) of the trough 8 during the normal conveyance period is 40 Hz (cycle 25 ms) has been described, but also at other frequencies such as 30 Hz and 50 Hz, for example. If the energization control is performed with the pattern 1 in the transport condition 1, the pattern 2 in the transport condition 2, and the pattern 3 in the transport condition 3, the same effect can be obtained.
[0047]
Further, the stop pattern is not limited to that described in the present embodiment, and may be set according to the type of trough, the article conveyed by the trough, and the like. The transport conditions are classified into three according to the transport time, but may be further subdivided, and according to this, the trough can be stopped more reliably.
[0048]
Next, an electromagnetic feeder according to a second embodiment will be described. The electromagnetic feeder according to the second embodiment is such that the stop pattern can be set manually in the electromagnetic feeder 1 according to the first embodiment. That is, the electromagnetic feeder according to the second embodiment is the same as the electromagnetic feeder 1 according to the first embodiment, as shown in FIG. The input means 41 having, for example, an input key or the like for manually selecting a stop pattern (pulse generation pattern) determined in advance according to the time of the conveyance period is provided. In addition to the function of the control unit 35 of the first embodiment, the control unit 35 ′ of the control device 30 ′ has a processing function when a stop pattern is selected by the input unit 41. When the stop pattern is manually selected by the means 41, the selected stop pattern data is read from the generated pattern storage means 34 and set, and the energization as in the first embodiment is performed based on the stop pattern. Take control. The switching element 32, the pulse generation unit 33, the transport period setting unit 31, and the generation pattern storage unit 34 may be the same as those in the first embodiment.
[0049]
According to the electromagnetic feeder according to the second embodiment, the effect of the electromagnetic feeder 1 according to the first embodiment can be achieved, of course, for example, when the trough is changed or the article is changed. However, a stop pattern in which the trough vibration converges most quickly can be selected from the stored stop patterns.
[0050]
【The invention's effect】
As described above, according to the present invention, after the normal transport period is over, the electromagnetic feeder has a stop pattern set as a pattern in which the convergence of trough vibration is accelerated among a plurality of stop patterns according to the time of the normal transport period. Therefore, the trough vibration is quickly damped and stopped regardless of the length of time. As a result, the accuracy of the amount of articles supplied by the electromagnetic feeder is improved.
[Brief description of the drawings]
FIG. 1 is a schematic side view of a combination weighing device according to a first embodiment of the present invention.
FIG. 2 is a side view of the electromagnetic feeder.
FIG. 3 is a block diagram showing a configuration of a control device of the electromagnetic feeder.
FIG. 4 is a time chart for explaining the convergence of the amplitude after the end of the normal conveyance period under conveyance condition 1;
FIG. 5 is an explanatory diagram of an energization pattern.
FIG. 6 is a diagram summarizing the amplitude attenuation effect when the conveyance condition and the pattern are changed.
FIG. 7 is a time chart for explaining the convergence of the amplitude after the end of the normal conveyance period in the conveyance condition 2;
FIG. 8 is a time chart for explaining the convergence of the amplitude after the end of the normal conveyance period under the conveyance condition 3;
FIG. 9 is a block diagram illustrating a configuration of an electromagnetic feeder control device according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electromagnetic feeder 2 Combination measuring device 7 Exciter 8 Trough 23 Electromagnet 34 Generation pattern storage means (storage means)
35, 35 'control means (energization control means, pattern setting means)

Claims (4)

An electromagnetic feeder that vibrates a trough by intermittently energizing an electromagnet to convey an article, and stores a plurality of intermittent energization patterns different from the normal conveyance period as stop patterns, and the time of the normal conveyance period And a pattern setting means for setting a pattern in which the convergence of trough vibration is accelerated from among the plurality of stop patterns stored in the storage means, and the conveyance period ends with the stop pattern set by the pattern setting means. An electromagnetic feeder, comprising: an energization control means for controlling energization after. The electromagnetic feeder according to claim 1, wherein the plurality of stop patterns vary at least the period of intermittent energization. The electromagnetic feeder according to claim 1, wherein the plurality of stop patterns vary at least intermittent energization ON times. A weighing apparatus comprising: the electromagnetic feeder according to any one of claims 1 to 3; and weighing means for weighing an article conveyed from the electromagnetic feeder.

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