JP5529499B2 - Device for measuring the weight of articles on a conveyor - Google Patents

Description

  The present invention relates to a weight measuring apparatus for measuring the weight of an article being conveyed on a conveyor, and in particular, the weight of a powder molded product made of a magnetic material after press molding and before sintering is measured on the conveyor. The present invention relates to an apparatus for measuring the weight of articles on a conveyor, which is suitable for use in measurement.

  In recent years, a technique in which a component having a complicated shape is molded from powder by pressing and then manufactured by sintering has been widely used. If it is possible to measure the weight of the powder molded product before sintering after pressing, it can be reused by removing the powder molded product with soot before sintering and pressing it again. Can be used effectively. However, since a powder molded product simply formed by a press is soft, measurement is not easy, and in particular, for a small part having a weight of about 1 gram, it is difficult to inspect each product, for example, in units of 10 or several tens. At last, it was difficult to measure all the products.

  On the other hand, as a weight measuring device for measuring the weight of an article being conveyed on a conveyor, for example, as described in Patent Documents 1 to 5, a load cell is provided on the lower side of the conveyor belt to measure the weight of the entire belt. So-called weighing conveyors for measuring are known.

JP 2008-268068 A JP 2008-195490 A JP 2008-145122 A JP 2007-108068 A JP 2000-525 A

  However, when the weight of the article is detected from the lower side of the conveyor belt, it is difficult to accurately measure the weight of the microparts in particular because it is affected by the vibration and tension of the belt.

  Furthermore, a dedicated weighing conveyor is required, which is not only expensive, but also has a problem that it is difficult to add to an existing conveyor later.

  The present invention has been made to solve the above-mentioned conventional problems, and it is possible to measure the weight of an article being conveyed on a conveyor at a high speed and with high accuracy even for a minute part. Furthermore, it is an object to provide a weight measuring device that is inexpensive and can be retrofitted to an existing conveyor.

The present invention is conveyed on the conveyor, a weighing device for measuring the weight of articles made of a magnetic material powder moldings, and an electromagnet for attracting the article from above, to the electromagnet for detecting the weight of the adsorbed product, and load cell integral with the electromagnet, when the article comes to the position of the electromagnet, adsorb article as on the electromagnet, after detecting the weight of the article, suction control means and, weighing equipment of the articles on the conveyor to a case for housing an integrated electromagnet and the load cell, comprising the for returning the articles on the conveyor to the electromagnet as an off more is obtained by solving the above problems.

Here, an article sensor is provided for detecting that the article has reached the upstream side of the conveyor of the electromagnet , and when the article is detected by the article sensor, the zero point of the load cell is adjusted so that the ambient temperature is It is possible to eliminate drift caused by change and the influence of dust.

Furthermore, when turned off the electromagnet, so as to apply a reverse voltage at the time of adsorption, the adsorbed articles electromagnet can be made to quickly away from the electromagnet.

  According to the present invention, the article conveyed on the conveyor is adsorbed from above, and the weight of the article is measured in a state away from the conveyor belt. It is possible to measure the weight of each product at high speed with high accuracy without being affected by the tension or tension.

Furthermore, because it does not contain the conveyor components are inexpensive, the existing conveyor, the integrated electromagnet and the load cell, only by adding a suction control means, can be easily retrofitted.

(A) Top view and (B) Front view showing the overall configuration of the embodiment of the present invention (A) Side view (B) Front view and (C) Bottom view showing details of the adsorption / measurement unit Block diagram showing details of display / control unit Flow chart showing the processing procedure Similarly, a time chart showing examples of timing and waveforms of each signal Time chart showing a modification of the potential applied to the electromagnet

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In this embodiment, as shown in FIGS. 1A (plan view) and (B) (front view), an article made of a magnetic material (a disk in the figure) being conveyed on the belt 12 of the conveyor 10 is shown. in the weight measuring device for measuring the weight of Jo article) 8, the articles 8 from above to adsorb siphoned magnetically, activatable electrodeposition magnet 22, and the article 8 which has been attracted to the electromagnet 22 Z-axis is a height adjusting means for adjusting the suction and measurement unit 20 which load cell 26 is accommodated for detecting the weight, gap G between the electromagnet 22 and the article 8 (see FIG. 1 (B)) A stage 28, a first optical sensor 30 which is an article sensor for detecting that the article 8 has reached a predetermined position on the upstream side of the conveyor 10 of the electromagnet 22 (the lower side in FIG. 1A), and the article 8 Is confirmed to have reached the position of the electromagnet 22 The zero point of the load cell 26 is adjusted based on the output of the second optical sensor 32 based on the output of the second optical sensor 32 and the output of the first optical sensor 30. When the article 8 comes to the position of the electromagnet 22, the electromagnet 22 is energized, the article 8 is attracted by being turned on, the load cell 26 detects the weight of the article 8, and then the energization to the electromagnet 22 is released. A display / control unit 40 including suction control means for returning the article 8 onto the belt 12 of the conveyor 10 as being off is provided.

  The adsorption / measurement unit 20 is configured as shown in detail in FIGS. 2A (side view) (B) (front view) and (C) (bottom view). A gap G (see FIG. 1B) between the article 8 on the belt 12 and the electromagnet 22 of the adsorption / measurement unit 20 supported by the Z-axis stage 28 by the mounting plate 20A shown in FIG. The height of the adsorption / measurement unit 20 can be adjusted so that the interval at which the article 8 can be adsorbed, for example, about 2 mm.

  The electromagnet 22 includes a core 22A, a coil 22B wound around the core 22A, and a mounting plate 22C to the load cell 26. Under the electromagnet 22, a cushioning rubber sheet 23 made of, for example, silicon rubber having a thickness of about 0.2 mm is provided to prevent the article from being damaged when the article 8 is attracted.

  The load cell 26 has, for example, a substantially parallelogram-shaped deformation frame 26A and, for example, a pair of strain gauges 26B attached to the top and bottom of the deformation portion. The load cell 26 is accommodated in the case of the adsorption / measurement unit 20 in order to prevent the influence of wind and temperature. The load cell 26 can be easily calibrated by inserting a weight from a load cell calibration hole 20B provided in the case of the adsorption / measurement unit 20. In FIG. 2B, reference numeral 21 denotes a plate for closing the load cell calibration hole 20B other than during calibration.

  Each of the first and second optical sensors 30 and 32 is a transmissive optical sensor including a pair of light projecting units 30A and 32A and light receiving units 30B and 32B.

  As shown in detail in FIG. 3, the display / control unit 40 zero-adjusts the indicated value of the rear load indicator 40B according to the outputs of the first and second optical sensors 30, 32, and A control circuit 40A for controlling the adsorption state of the electromagnet 22, a load indicator 40B for displaying the weight of the article 8 according to the output of the load cell 26, and an article according to the output of the load indicator 40B And a determination circuit 40C for determining whether or not the weight of 8 is within an allowable range.

  The operation will be described below with reference to the flowchart of FIG. 4 and the time chart of FIG.

  First, a zero signal is generated when the light from the light projecting unit 30A to the light receiving unit 30B is blocked by the article 8 and the first optical sensor 30 is turned on (determination result Yes in step 100 in FIG. 4). The display value of the load indicator 40B is set to zero (step 110). As a result, it is possible to eliminate drifts due to changes in ambient temperature and the influence of dust.

  Next, when the light from the light projecting unit 32A to the light receiving unit 32B is blocked by the article 8 and the second optical sensor 32 is turned on (determination result Yes in step 120), the electromagnet 22 is energized to remove the article. It is sucked and attracted by magnetic force (step 130). The time T1 (see FIG. 5) for turning on the suction signal can be set by a timer, for example.

  After the adsorption, as shown in FIG. 5, after waiting for a predetermined time to elapse (determination result Yes in step 140), a determination start signal is output, and the first peak value of vibration due to adsorption is removed. After the determination start signal is input, the values measured by the load cell 26 are averaged, and the average instruction value is displayed (step 150). This interval averaging can improve accuracy. This averaging interval can also be set by a timer, for example.

  Next, the average instruction value is compared with the set values (for example, the HI set value and the LO set value in FIG. 5), and the article weight is set to, for example, the OK range between the HI set value and the LO set value, and other NGs. It is determined which of the ranges (step 160), the determination result output signal shown in FIG. 5 is output, the suction is released (step 170), the article 8 is returned to the conveyor 10, and the measurement is finished.

  Here, the HH set value higher than the HI set value and the LL set value lower than the LO set value are provided between the HI set value and the HH set value or between the LO set value and the LL set value. In addition, the number of times each measurement value enters is counted, and the tendency control is performed to correct the press when it continues for a predetermined number of times. If there is no need to perform trend control, the HH set value and the LL set value can be omitted.

If it is determined that the failure is determined in the step 160, the display / control unit 40 displays, for example, an NG signal on the LED and outputs the determination result to the outside, for example, by driving a separately provided air cylinder or the like. The product can be eliminated.

  Further, when releasing the adsorption in the step 170, the potential is not simply made zero, but an oscillating voltage whose potential changes in the reverse direction as shown in FIG. Even with an electromagnet using a simple core, it is possible to smoothly release the adsorption. In the case of a high-grade (expensive) electromagnet using a core with little residual magnetism, such as a relay electromagnet, the control as shown in FIG. 6 is unnecessary.

  In the present embodiment, since the electromagnet 22 and the load cell 26 are integrated and accommodated in the case, the influence during measurement such as vibration, wind, and acceleration can be reduced.

In the present embodiment, since the article 8 was magnetic, electromagnets 22 can adsorb with, it is easy, light and inexpensive absorption Chakusu Rukoto. The article 8 is not limited to a disk-shaped magnetic body.

Also, the height of the article 8 is constant, electrostatic and the gap between the magnet 2 2 is constant, it is possible to omit the height adjusting function according to Z-axis stage 28.

Further, when the output of the load cell 2 6 is stable, it may be omitted zero adjustment by the output of the first optical sensor 30.

  Further, the optical sensors 30 and 32 are not limited to the transmissive type including each pair of light projecting unit and light receiving unit, and a reflection type or other type of article sensor may be used.

  Further, the configuration of the display / control unit 40 is not limited to the embodiment.

The present invention is suitable for measuring the weight of a fine powder molded product, but the measurement object of the present invention is not limited to this, and a large powder molded product can also be measured.

8. Articles (powder molded products)
DESCRIPTION OF SYMBOLS 10 ... Conveyor 12 ... Belt 20 ... Adsorption / measurement part 22 ... Electromagnet 22A ... Core 22B ... Coil 26 ... Load cell 26A ... Deformation frame 26B ... Strain gauge 28 ... Z-axis stage 30, 32 ... Optical sensor 40 ... Display / control part

Claims (3)

A weight measuring device for measuring the weight of an article made of a magnetic powder powder product that is being conveyed on a conveyor,
An electromagnet for adsorbing the article from above;
For detecting the weight of adsorbed article to the electromagnet, a load cell integral with the electromagnet,
When the article comes to the position of the electromagnet, adsorb article as on the electromagnet, after detecting the weight of the article, and suction control means for returning the articles on the conveyor as an off-the electromagnet,
A case for accommodating an integrated electromagnet and load cell;
An apparatus for measuring the weight of an article on a conveyor. An article sensor for detecting that an article has reached the upstream side of the conveyor of the electromagnet is provided, and the zero point of the load cell is adjusted when the article is detected by the article sensor. The apparatus for measuring a weight of an article on a conveyor according to claim 1. The apparatus for measuring a weight of an article on a conveyor according to claim 1 , wherein when the electromagnet is turned off, a potential opposite to that at the time of adsorption is applied.

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