JP2969990B2 - Automatic weight sorter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for automatically measuring the weight of each sample based on the measured value of each sample by the weight measurement unit and a preset weight level while continuously loading and unloading the samples to and from the weight measurement unit. The present invention relates to a device for sorting, for example, a device called an auto checker or the like, which is used for checking the filling amount of a sample and classifying the sample into a non-defective product and a defective product.

[0002]

2. Description of the Related Art In general, in a weight sorter of this type, a weighing conveyor or the like is used as a weight measuring unit, and a carry-in conveyor and an unloading conveyor are provided before and after the weighing conveyor, and the weight of the sample on the weighing conveyor is sequentially measured. , Non-defective / defective products, etc.

[0003]

In the above-described apparatus, due to its configuration, it takes a predetermined time until the measurement output rises after the sample is put on the weight measuring section and reaches a constant value. For this reason, there is a problem that if the sorting speed is increased, the sorting accuracy is deteriorated, and if the sorting accuracy is emphasized, the number of processes per unit time is reduced.

An object of the present invention is to provide an automatic weight sorter capable of increasing the number of pieces processed per unit time without reducing the sorting accuracy.

[0005]

Means for Solving the Problems A configuration for achieving the above object will be described with reference to a basic conceptual diagram shown in FIG. 1. According to the present invention, a weight measuring unit a and its weight measuring unit a
The weight range of the sample W is determined by comparing the weight data from the weight measuring unit a with one or more predetermined weight levels, and a sample loading unit b and a sample unloading unit c that sequentially load and unload the sample W. Determining means d for determining
In a device provided with sample sorting means e for sorting out the sample W carried out based on the determination result, a force generating means f for applying a force in the same direction as the direction in which the sample weight acts on the weight measuring section a; a detecting means g for detecting that the sample W has finished riding on a, and control means h for controlling the force generated by the force generating means f. Until it is detected that the next sample W has finished riding on the section a, the force generating means f is configured to generate a force such that the output of the weight measuring section a maintains a predetermined value. Attached.

Here, by applying a force by the force generating means f, the value to keep the output of the weight measuring section a constant after the judgment by the judging means d is determined is the sample weight itself used for the judgment, or And the standard weight value of the sample.

[0007]

The reason why it takes a long time for the output of the weight measuring unit to stabilize in the conventional device is that the output of the weight measuring unit becomes zero after the previous sample is unloaded, and the next sample is weighed in that state. This is because it takes a considerable amount of time before the rider gets on the machine part to delay the rise based on the response characteristics of the weight sensor and to settle the influence of the impact load due to the loading and unloading of the sample.

In the present invention, after the weight of the previous sample is determined, the output of the weight measuring section a is a constant value near the weight value until the sample is carried out and the next sample finishes riding on the weight measuring section a. So that the dummy weight is applied from the outside by the force generating means f so that
The output of the weight measuring unit a is always kept at a substantially constant value, the influence of the above-mentioned response delay and impact load is reduced, and high-speed sorting with high accuracy is enabled.

[0009]

FIG. 2 is an overall configuration diagram of an embodiment of the present invention.
(A) is a front view, and (B) is a plan view. The weight measuring unit 1 is configured such that a conveyor (weighing conveyor) 1b is mounted on a sensing unit of a weight sensor 1a such as a load cell, and has basically the same configuration as a conventional measuring conveyor. A carry-in conveyor 2 and a carry-out conveyor 3 are arranged before and after the weight measuring section 1. In the vicinity of the unloading conveyor 3, two arms 5 a and 5 b and their actuators (not shown) are provided. Based on a command from the control unit 40 in the control console 4, the sample on the unloading conveyor 3 is Good product,
A sorting device 5 for sorting to either (+) defective products or (-) defective products is provided. The control console 4 accommodates the control unit 40 and its peripheral circuits.

A light source 6 and a light receiving element 7 are arranged on both sides of the weight measuring section 1. When the sample is completely loaded on the weight measuring section 1, the sample is incident on the light receiving element 7. And the output of the light receiving element 7 allows the user to know that the sample has completely laid on the weight measuring section 1. Conveyor 1 of weight measurement unit 1
b, a force generating device 8 capable of applying a downward force to the conveyor 1b is arranged. This force generating device 8 can be constituted by an electromagnetic force generating device as exemplified in a cross-sectional view in FIG.

In the example shown in FIG. 3, similarly to the voice coil type magnet of the speaker, a force is generated in the coil by generating an annular static magnetic field and causing a current to flow through the coil therein. Specifically, the permanent magnet 8a, the pole piece 8b, and the yoke 8c form a magnetic circuit for generating the above-described static magnetic field, and a movable coil 8d is provided inside the static magnetic field. In such a configuration, the magnetic circuit side is fixed to the outside, and the coil 8 d is mounted on the conveyor 1 b of the weight measuring unit 1, whereby the coil 8 d is mounted.
It is configured such that a downward force corresponding to the current flowing through d is applied to the conveyor 1b.

FIG. 4 is a block diagram showing an example of the circuit configuration of the embodiment of the present invention. The control unit 40 includes a setting unit 41 for setting a weight level to be classified and an output from the weight sensor 1a of the weight measuring unit 1 to the amplifier 9 and the A / D converter 1
A comparing unit 42 for comparing with the weight level set via the setting unit 41 and outputting the result;
A storage unit 43 for storing the output of the converter 10 at a predetermined timing; a calculation unit 44 for calculating the difference between the content of the storage unit 43 and the output of the A / D converter 10 every moment; a force generation unit for the calculation result A switch unit 45 for supplying / stopping the light to and from the light receiving element 7;
And a timing control section 46 for supplying a timing signal to the switch section 45, and the like.
Actually, it can be constituted by a microcomputer.

The output of the arithmetic unit 44 is converted into an analog signal by the DA converter 11, and then supplied to the force generator 8 via the switch unit 45. The force to act on is determined. Specifically, the output signal of the DA converter 11 is supplied to the coil 8d of the force generator 8 via a power amplifier or the like, and determines the current flowing therethrough.

Next, the operation and operation of the embodiment of the present invention having the above configuration will be described with reference to FIG. FIG. 5 is a graph showing the relationship between the state of the sample flow, the output signal waveform of the weight measuring unit 1, the timing signal from the timing control unit 46 to each unit, and the force generated by the force generating device 8.

In FIG. 1, (A) is a graph showing the change with time of the output of the weight sensor 1a obtained only by transporting the sample. In the conventional apparatus, only the output shown in (A) is obtained. (B) shows the change over time of the output of the force generator 8 and the weight sensor 1a in the embodiment of the present invention.
3 is a graph showing the change of the actual output over time, and FIG. 4C is a time chart showing a timing signal output from the timing control section 46 to each section.

As shown in FIG. 1A, the sample is measured by the weight measuring unit 1.
When you start riding, the output of the weight sensor 1a increases,
After the ride is completed, the output does not stabilize immediately due to a response delay of the sensor or the like, and a stable weighing value is obtained after a certain time has elapsed. The comparison of the sample weight with the set weight by the comparing section 42 determines whether the sample weight is good or bad. After the measurement value is stabilized, after the signal from the light receiving element 7 detects that the sample has completely ridden, for example, This is performed by generating a timing signal from the timing control section 46 when the time has elapsed. The comparison result of the comparison unit 42 is supplied to the sample sorting unit 5, and when the sample reaches the sample unloading conveyor 3, the sample is sorted into a non-defective product, a (+) defective product, and a (-) defective product.

At this time, the timing control section 46 gives a storage command to the storage section 43 to store the weight value at this time. At this time, the stored contents up to that point are reset. The arithmetic unit 44 calculates the difference between the content α of the storage unit 43 and the instantaneous weight data β from the AD converter 10, and the arithmetic result (α-β) is calculated by the DA converter 11. After being converted into an analog signal, it is supplied to the force generator 8 via the switch unit 45. The timing control section 46 closes the switch section 45 after completion of the determination in the comparison section 42, and generates a timing signal such that the switch section 45 is opened when the next sample is completely on the weighing device 1. .

In this manner, the force generator 8 determines the difference (α−) calculated by the arithmetic unit 44 after the weight of a certain sample is determined and until the next sample finishes riding on the weight measuring unit 1.
An analog signal corresponding to β) is supplied. As described above, the force generator 8 generates a force corresponding to the supplied signal and causes the force to act on the weight sensor 1a in the downward direction (in the same direction as the working direction of the sample weight). Even if the sample moves and starts descending from the weighing unit 1,
Until the next sample completely rides on the weight measuring section 1, a force such that α-β = 0 is applied to the weight sensor 1a, and the output of the weight sensor 1a continues to be the value at the time of the immediately preceding determination. Will be kept.

As a result, the output of the weight sensor 1a is
As shown in (B), when the output of the next sample is completely completed and the output is switched to the load by only the sample weight, only the difference of the difference between the previous sample weight and the current sample weight occurs. The time required for the weight signal to stabilize depends on only the sample weight shown in (A).
The output is greatly reduced as compared with the output fluctuation from 0, the time required for determining one sample is shortened, and the efficiency is improved without deteriorating the accuracy. Alternatively, when an equivalent stabilization time is provided, more accurate determination can be made.

When the force generating device 8 uses the above-described electromagnetic force generating mechanism, a large magnet and a coil are required to generate a large force, which causes a cost increase. As shown in FIG.
What is necessary is just to comprise so that generated force may be expanded and transmitted to the weight sensor 1a using 0. Further, in the above-described embodiment of the present invention, the case where the weight sensor 1a and the force generating device 8 are separately provided is illustrated. However, as shown in FIG. Can be integrated. That is, an electromagnetic force balanced type sensor is used as the weight sensor, and the permanent magnet 71a and the pole piece 71 are used.
A sensor coil 72 and a dummy force generating coil 73 are inserted in the same static magnetic field created by b and the yoke 71c. In this case, the coil 72 and the coil 73 are wound around a common winding frame 74, a measuring conveyor on which the sample is placed is mounted on the winding frame 74, and the yoke 71c is fixed to the installation surface.

FIG. 8 shows a circuit configuration in which such an electromagnetic force balancing type weight sensor is used and a dummy force generating coil 73 is placed in a static magnetic field in which the electromagnetic force balancing coil 72 of this sensor is placed. It is a block diagram showing an example. In this figure, the same members as those shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted. The weighing conveyor 1b transports the sample from left to right in the figure by a motor (not shown) or the like. The weighing conveyor 1b is movably supported only in the vertical direction by a known roberval mechanism (not shown, also referred to as a parallel guide).

The measuring conveyor 1b is provided with an electromagnetic force balancing coil 72 (also referred to as a force coil) and a dummy force generating coil 73. Therefore, the measuring conveyor 1b includes not only the sample weight but also the two. Coil 7
The forces generated by 2, 73 act. The weighing conveyor 1b is slightly displaced downward when a sample is placed thereon, but this displacement is detected by a displacement sensor 81 and amplified by a preamplifier 82, and then the PID control unit 83
, And the output of the power amplifier 84 is supplied to the electromagnetic force balancing coil 72.
Thereby, the displacement sensor 8 is connected to the electromagnetic force balancing coil 72.
1, a current is generated in the coil 72 placed in the static magnetic field, and the force acts in the direction of returning the displacement due to the sample weight to the weighing conveyor 1b. As a result, the displacement of the weighing conveyor 1b is controlled to always become 0 by the force generated by the electromagnetic force balancing coil 72. The current value required for this equilibrium is proportional to the sample weight. This is a general known principle of electromagnetic balances.

The value of the current flowing through the balancing coil 72 is converted into a voltage value by the measuring resistor R, and the voltage is supplied to the A / D converter 10.
Is converted into weight data after being digitized by the controller 40.
Is compared with the set value of the setting unit 41 in the same manner as in the above-described embodiment.
(+) Defective / (-) Defective. Voltage generated in the measuring resistor R, together are supplied to the voltage memory 85 comprising a capacitor 85a and a buffer 85b through the switches S _1, to the + input terminal of the differential input power amplifier 87 via the buffer 86 supply Is done.

The output terminal of the voltage memory 85 is connected to the negative input terminal of the differential input power amplifier 87. The output of the differential input power amplifier 87 is connected to the switch S.
₂ is configured to be supplied to the dummy force generating coil 73 in a closed state. The timing control unit 46 supplies a timing signal to each part by exactly the same timings as in the example shown in FIG. 5, to support execution of the storage operation by closing the switch S ₁ described above,
The switch unit 45 is a switch S _{2 in} the example of FIG.
Is equivalent to

[0025] Now, in the above configuration, determination time switch S ₁ is temporarily closed in by the comparison unit 42, the analog voltage e is stored in the voltage memory 85 is charged in the capacitor 85a at that time. Then switch S ₂
Is closed, and the output of the differential input power amplifier 87 flows through the dummy force generating coil 73. The output of the differential input power amplifier 87 corresponds to the difference between the contents of the voltage memory 85 and the current converted value of the current value flowing through the electromagnetic force balancing coil 72, and thus corresponds to α-β described above. The same operation and effect as described in the above are obtained.

In the embodiment shown in FIGS. 7 and 8, the weight sensor and the force generating device can be compactly integrated and a part can be shared, and an electromagnetic sensor is used as the weight sensor. It is considered to be the optimal configuration in the case. In each of the above embodiments, a case has been described in which, after the previous determination of the sample by the force generator, the generated force of the force generator is controlled so that a force equal to the weight of the sample acts on the weight sensor. Instead of the previous sample weight value,
The force generating device may be configured to control the force generator so that a force corresponding to a preset standard weight acts on the weight sensor.

As the standard weight, for example, the average weight of the sample to be sorted or the median of the weight range regarded as a non-defective product can be adopted. In this case, the same operation and effect as those of the above examples can be obtained. . 9 and 10 show the main parts of the circuit configuration diagram in this case. The example of FIG. 9 is a modification of the example of FIG. 4, and the storage unit 43 of FIG.
Instead, a standard weight value α ′ preset by the setting unit 41 is introduced into the arithmetic unit 44, and the difference α ′ is compared with the current output β of the A / D converter 10, α′−β And the result is supplied to the DA converter 11.

The example shown in FIG. 10 is a modification of the example shown in FIG. 8, and the + input terminal of the differential input power amplifier 87 is replaced with an output of the voltage memory 85 in FIG.
The standard weight value set in advance in the DA converter 10
It is derived after being analogized by 0. With the configuration shown in FIGS. 9 and 10, the output of the weight measuring section is maintained at the standard weight value until the next sample finishes riding on the weight measuring section after the end of the previous sample determination.

[0029]

As described above, according to the present invention, even if a sample is conveyed and starts to descend from the weighing unit after the weight of the sample has been determined on the weighing unit, the weight measurement can be performed. The output of the unit will be maintained at the value corresponding to the sample weight value or standard weight value until the next sample is completely loaded, and even if the next sample rides on the weight measurement unit, the output fluctuation Is small, and the effect of the shock load when loading and unloading the sample is reduced.
The time required for the output to stabilize, compared to the case where the output of the weighing unit fluctuates from 0 to its weight value when the next sample rides on the weighing unit as in the prior art, and thus the time required until the determination The waiting time is greatly reduced.

As a result, the processing capacity per unit time is greatly improved when the distribution is performed with the same accuracy as the conventional one, and the distribution accuracy is significantly increased when the processing is performed with the conventional processing time. Will be improved.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is a front view (A) and a plan view (B) of an embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a configuration example of the force generating device 8;

FIG. 4 is a block diagram showing a circuit configuration example according to the embodiment of the present invention;

FIG. 5 is a diagram for explaining the operation and operation of the embodiment of the present invention.

FIG. 6 is a configuration diagram of a force generation device according to another embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing a configuration of a weight sensor and a force generating device according to still another embodiment of the present invention.

8 is a block diagram showing an example of a circuit configuration when the configuration shown in FIG. 7 is used.

FIG. 9 is a block diagram showing a main part of a circuit configuration according to still another embodiment of the present invention.

FIG. 10 is a block diagram showing a main part of a circuit configuration according to still another embodiment of the present invention.

[Explanation of symbols]

 1 ··· Weight measuring unit 1a ··· Weight sensor 1b ··· Weighing conveyor 2 ··· Loading conveyor 3 ··· Unloading conveyor 4 ··· Control console 40 ··· Control unit 41 setting unit 42 comparing unit 43 storage unit 44 calculating unit 45 switch unit 46 timing control unit 10 A- D converter 11 ··· DA converter 5 ··· Distributing device 6 ··· light source 7 ··· light receiving element 8 ··· force generator 72 ··· for electromagnetic force balancing Coil 73: Coil for generating dummy force 81: Displacement sensor 83: PID control unit 84: Power amplifier 85: Voltage memory 86: Buffer 87:・ Differential input power amplifier

Claims (1)

(57) [Claims] 1. A weight measuring section, a sample loading section and a sample unloading section for sequentially loading and unloading a sample into and from the weight measuring section, and weight data from the weight measuring section and one or more predetermined weights Determining means for determining the weight range of the sample by comparison with the level, and a device provided with sample sorting means for sorting the sample carried out based on the determination result, wherein the direction in which the sample weight acts on the weight measuring unit; Force generating means for applying a force in the same direction, detecting means for detecting that the sample has finished riding on the weight measuring unit, and control means for controlling the force generated by the force generating means, the control means, After the determination by the determination means is completed, a force is generated such that the output of the weight measurement unit maintains a predetermined value until it is detected that the next sample has finished riding on the weight measurement unit. Automatic weight sorter characterized in that the automatic weight sorter is configured to generate the weight.