JPH0134904B2 - - Google Patents
Info
- Publication number
- JPH0134904B2 JPH0134904B2 JP57222820A JP22282082A JPH0134904B2 JP H0134904 B2 JPH0134904 B2 JP H0134904B2 JP 57222820 A JP57222820 A JP 57222820A JP 22282082 A JP22282082 A JP 22282082A JP H0134904 B2 JPH0134904 B2 JP H0134904B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- received signal
- maximum value
- metal plates
- minimum value
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000002184 metal Substances 0.000 claims description 21
- 230000005674 electromagnetic induction Effects 0.000 claims description 3
- 230000010355 oscillation Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 6
- 238000005070 sampling Methods 0.000 description 6
- 238000001514 detection method Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000007257 malfunction Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000000284 extract Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H7/00—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles
- B65H7/02—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors
- B65H7/06—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors responsive to presence of faulty articles or incorrect separation or feed
- B65H7/12—Controlling article feeding, separating, pile-advancing, or associated apparatus, to take account of incorrect feeding, absence of articles, or presence of faulty articles by feelers or detectors responsive to presence of faulty articles or incorrect separation or feed responsive to double feed or separation
Landscapes
- Measurement Of Current Or Voltage (AREA)
- Geophysics And Detection Of Objects (AREA)
- Controlling Sheets Or Webs (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Description
【発明の詳細な説明】
ａ 技術分野
この発明は２枚送りされた金属板を磁気的に検
出する非接触の２枚送り検出器に関する。Detailed Description of the Invention: a. Technical Field The present invention relates to a non-contact two-sheet feed detector that magnetically detects two metal plates that have been fed.
ｂ 従来技術及びその欠点
プレス工程などにおいて、被加工物である金属
板が誤つて２枚重ねになつて供給されると、金型
を破損する恐れがあるので、この種の２枚重ねを
検出する手段が従来より提案実施されている。b. Prior art and its disadvantages If two metal plates, which are workpieces, are mistakenly supplied in a stacked state during a press process etc., there is a risk of damaging the mold, so this kind of double stacking cannot be detected. Measures to do this have been proposed and implemented in the past.
その一つの手段として２枚重ねを磁気的に検出
する非接触の検出器がある。従来の２枚重ね検出
器は検出される金属板に近接して設けられる送信
コイルと受信コイルを含み、送信コイルから発せ
られた交番磁界に基づく電磁誘導作用によつて受
信コイルに誘起される信号の大きさをもつて金属
板が１枚又は２枚であるかを判別している。 One means for this is a non-contact detector that magnetically detects the stacking of two sheets. A conventional two-layer detector includes a transmitting coil and a receiving coil that are installed close to the metal plate to be detected, and a signal is induced in the receiving coil by electromagnetic induction based on an alternating magnetic field emitted from the transmitting coil. It is determined whether there is one or two metal plates based on the size of the metal plate.
第１図は前述したような従来の２枚送り検出器
の動作波形図を示す。例えば、同図イは金属板が
一枚のとき、同図ロは金属板が２枚のときに受信
コイルに誘起される受信信号と、そのときの検出
信号である。すなわち、従来の検出器は一定の設
定レベルに対し、受信信号を例えば包絡線検波し
た出力の一定の設定レベルに対する大小でもつ
て、イ−２図、ロ−２図の如き検出信号を出力す
ることにより金属板が１枚であるか、２枚である
かを知らせている。 FIG. 1 shows an operating waveform diagram of the conventional two-sheet feed detector as described above. For example, A in the figure shows a reception signal induced in the receiving coil when there is one metal plate, and B in the figure shows a detection signal induced in the receiving coil when there are two metal plates. In other words, conventional detectors output detection signals as shown in Figures E-2 and R-2, regardless of the magnitude of the output obtained by envelope-detecting the received signal, for example, with respect to a certain set level. This tells you whether there is one or two metal plates.
しかしながら、かかる検出器の受信コイルは、
プレス工程等で使用される例えば、交流ソレノイ
ドや金属板吸着用の交流電磁石等から発生する漏
洩磁束に基づく外部磁界の影響を受け易いため、
受信信号に雑音成分が重畳することがある。 However, the receiving coil of such a detector is
Because it is easily affected by external magnetic fields based on leakage magnetic flux generated from, for example, AC solenoids and AC electromagnets used for adhering metal plates, used in pressing processes, etc.
Noise components may be superimposed on the received signal.
例えば、第１図ハ−１は同図ロ−１に示した金
属板が２枚のときの受信信号に雑音成分が重畳し
た波形を示している。その結果、この信号の包絡
線検波出力は設定レベルより高いため、同図ハ−
２に示すように誤つた検出信号（金属板が１枚で
あるという信号）を出力する。このように従来の
検出器は外部磁界に影響されて、誤動作しやすい
という欠点がある。 For example, FIG. 1 H-1 shows a waveform in which a noise component is superimposed on the received signal when there are two metal plates shown in FIG. 1 R-1. As a result, the envelope detection output of this signal is higher than the set level, so
As shown in 2, an erroneous detection signal (a signal indicating that there is only one metal plate) is output. As described above, conventional detectors have the disadvantage of being susceptible to malfunctions due to the influence of external magnetic fields.
また、かかる欠点に起因して、従来の検出器は
前記漏洩磁束を発する機器から受信コイルを遠ざ
ける必要があるという、受信コイルの取付上の制
約が大きい。 Further, due to this drawback, the conventional detector has a large restriction in mounting the receiving coil, which requires the receiving coil to be placed away from the device that emits the leakage magnetic flux.
一方、外部磁界の影響を少くするために、検出
器の応答速度を遅くする方法も考えられるが、こ
のような方法を採ると小さな被検出物や通過速度
の速いものの検出が困難になる。従つて、前記方
法は実用的でない。 On the other hand, in order to reduce the influence of external magnetic fields, it is possible to consider a method of slowing down the response speed of the detector, but if such a method is adopted, it becomes difficult to detect small objects to be detected or objects that pass through the sensor quickly. Therefore, the method is not practical.
ｃ 発明の目的
この発明は外部磁界の影響によつて誤動作する
ことのない２枚送り検出器を提供することにあ
る。c. Object of the Invention The object of the present invention is to provide a two-sheet feed detector that does not malfunction due to the influence of external magnetic fields.
ｄ 発明の特徴
この発明は、受信信号から、その最大包絡線に
関連した最大値信号と、最小包絡線に関連した最
小値信号とを抽出し、前記２つの信号の差動出力
と設定レベルを比較することにより金属板の２枚
送りを検出することを特徴としている。d Features of the Invention This invention extracts from a received signal a maximum value signal related to its maximum envelope and a minimum value signal related to its minimum envelope, and calculates the differential output and set level of the two signals. It is characterized by detecting the feeding of two metal plates by comparison.
ｅ 実施例の説明
第２図はこの発明に係る２枚送り検出器の一実
施例の構成を略示したブロツク図である。e Description of Embodiment FIG. 2 is a block diagram schematically showing the structure of an embodiment of a two-sheet feed detector according to the present invention.
同図において、１及び２は被検出物である金属
板Ｐに近接して設けられる送信コイル及び受信コ
イルである。送信コイル１は発振器３から商用周
波数よりも高い周波数の発振出力を与えられるこ
とに基づき、金属板Ｐに交番磁界を与える。一
方、受信コイル２は金属板Ｐを介して交番磁界を
検知し、電磁誘導作用によつて誘起された受信信
号を出力する。 In the figure, 1 and 2 are a transmitting coil and a receiving coil provided close to a metal plate P, which is an object to be detected. The transmitting coil 1 applies an alternating magnetic field to the metal plate P based on the fact that the oscillator 3 provides an oscillation output with a frequency higher than the commercial frequency. On the other hand, the receiving coil 2 detects an alternating magnetic field via the metal plate P and outputs a received signal induced by electromagnetic induction.
４は送信コイル１に与えられる発振出力の一部
を入力し、これと同期した同一周波数のサンプリ
ングパルスとリセツトパルスをそれぞれ出力する
同期パルス発生回路であり、サンプリングパルス
の位相はリセツトパルスのそれよりも若干進んで
いる。 4 is a synchronizing pulse generating circuit which inputs a part of the oscillation output given to the transmitting coil 1 and outputs a sampling pulse and a reset pulse of the same frequency in synchronization with this, and the phase of the sampling pulse is different from that of the reset pulse. is also making some progress.
SW１〜SW４はスイツチング回路であり、SW
１及びSW２は制御信号としてサンプリングパル
スを、SW３及びSW４はリセツトパルスをそれ
ぞれ入力している期間中、各スイツチング回路は
閉成する。 SW1 to SW4 are switching circuits, and SW1 to SW4 are switching circuits.
Each switching circuit is closed during the period when sampling pulses are input as control signals to SW1 and SW2, and reset pulses are input to SW3 and SW4, respectively.
５は受信コイル２から受信信号を与えられる最
大値保持回路である。この最大値保持回路５は受
信信号の最大値を保持し、これをスイツチング回
路SW１を介してサンプル保持回路７Ａに与え
る。そして、スイツチング回路SW３が閉成され
ると同時にリセツトされ、その出力は負の電源電
圧にまで引き下げられるが、前記スイツチング回
路SW３が開放した後は、前記受信信号の次の最
大値を保持する。 Reference numeral 5 denotes a maximum value holding circuit to which a received signal is applied from the receiving coil 2. The maximum value holding circuit 5 holds the maximum value of the received signal and supplies it to the sample holding circuit 7A via the switching circuit SW1. Then, the switching circuit SW3 is reset at the same time as it is closed, and its output is lowered to the negative power supply voltage, but after the switching circuit SW3 is opened, the next maximum value of the received signal is held.
６は前記最大値保持回路５と同様に、受信信号
を与えられる最小値保持回路である。この最小値
保持回路６は受信信号の最小値を保持し、これを
スイツチング回路SW２を介してサンプル保持回
路７Ｂに与える。そして、スイツチング回路SW
４が閉成されると同時にリセツトされ、その出力
は正の電源電圧にまで引き上げられるが、前記ス
イツチング回路SW４が開放した後は、前記受信
信号の次の最小値を保持する。 Similarly to the maximum value holding circuit 5, 6 is a minimum value holding circuit to which a received signal is applied. This minimum value holding circuit 6 holds the minimum value of the received signal and supplies it to the sample holding circuit 7B via the switching circuit SW2. And the switching circuit SW
4 is closed and its output is pulled up to the positive supply voltage, but after the switching circuit SW4 opens, it holds the next minimum value of the received signal.
８はサンプル保持回路７Ａ及び７Ｂの出力信号
をそれぞれ入力し、これらの差動出力を与える差
動演算器、９は前記差動出力を与えられて、これ
と設定レベルとを比較する比較回路である。 8 is a differential arithmetic unit which inputs the output signals of the sample holding circuits 7A and 7B, respectively, and provides a differential output thereof; 9 is a comparison circuit which receives the differential output and compares it with a set level; be.
次に、上述した如き構成の２枚送り検出器の動
作について説明する。 Next, the operation of the two-sheet feed detector configured as described above will be explained.
第３図及び第４図は第２図に示した２枚送り検
出器の動作波形図である。 3 and 4 are operational waveform diagrams of the two-sheet feed detector shown in FIG. 2.
発振器３の発振出力が送信コイル１に与えられ
る結果、金属板Ｐは励磁される。これにより受信
コイル２に受信信号が誘起される。例えば、金属
板が２枚送られ、しかも、外部磁界の影響によ
り、受信コイル２から第３図イに示すような受信
信号が出力されたとする。但し、同図は説明の都
合上、雑音成分のパルス幅に対し発振出力の周期
を拡大して描いている。 As a result of the oscillation output of the oscillator 3 being given to the transmitting coil 1, the metal plate P is excited. As a result, a reception signal is induced in the reception coil 2. For example, suppose that two metal plates are sent and, furthermore, due to the influence of an external magnetic field, the reception coil 2 outputs a reception signal as shown in FIG. 3A. However, for convenience of explanation, the figure shows the period of the oscillation output expanded with respect to the pulse width of the noise component.
発振器３の発振出力の一部は同期パルス発生回
路４に与えられる結果、第３図ロ及びハを示す如
きリセツトパルスとサンプリングパルスをそれぞ
れ出力する。 A part of the oscillation output of the oscillator 3 is applied to the synchronizing pulse generating circuit 4, which outputs a reset pulse and a sampling pulse as shown in FIG. 3 (b) and (c), respectively.
最大値保持回路５はリセツトパルスの一周期内
に表われる受信信号の最大値を保持する。発振器
３の発振周波数は商用交流電源の周波数よりも十
分高く定められるので、通常、雑音成分のパルス
幅は発振周期すなわちリセツトパルスの周期より
も十分大きい。従つて、受信信号の周波数はリセ
ツトパルスの周波数とほとんど同じであるとして
取り扱うことができる。それ故、最大値保持回路
５は受信信号の１周期ごとの最大値を保持するか
ら、第３図ニに示す如き信号を出力する。 The maximum value holding circuit 5 holds the maximum value of the received signal that appears within one cycle of the reset pulse. Since the oscillation frequency of the oscillator 3 is set to be sufficiently higher than the frequency of the commercial AC power supply, the pulse width of the noise component is usually sufficiently larger than the oscillation period, that is, the period of the reset pulse. Therefore, the frequency of the received signal can be treated as almost the same as the frequency of the reset pulse. Therefore, the maximum value holding circuit 5 holds the maximum value of the received signal for each period, and outputs a signal as shown in FIG. 3D.
一方、最小値保持回路６は前記回路５と同様
に、受信信号の１周期ごとの最小値を保持し、第
３図ホに示す如き信号を出力する。 On the other hand, the minimum value holding circuit 6, like the circuit 5, holds the minimum value for each cycle of the received signal and outputs a signal as shown in FIG. 3E.
そして、スイツチング回路SW１及びSW２が、
リセツトパルスよりも若干位相の進んだサンプリ
ングパルスによつて制御される結果、サンプル保
持回路７Ａ及び７Ｂは受信信号の１周期ごとの最
大値及び最小値を連ねた階段状の流形をした最大
値信号と最小値信号を与える。第４図イ（但し、
第３図より時間軸を短縮して示してある。）に示
す波形Ａは前記最大値信号を、波形Ｂは最小値信
号をそれぞれ示している。すなわち、最大値信号
は第３図イに示すように受信信号の最大包絡線
L1に関連し、一方、最小値信号は最小包絡線L2
に関連している。 Then, the switching circuits SW1 and SW2 are
As a result of being controlled by a sampling pulse whose phase is slightly ahead of that of the reset pulse, the sample holding circuits 7A and 7B produce a maximum value in the form of a step-like flow that is a series of maximum and minimum values for each period of the received signal. Give the signal and the minimum value signal. Figure 4 A (However,
The time axis is shown shorter than in FIG. 3. Waveform A shown in ) represents the maximum value signal, and waveform B represents the minimum value signal. In other words, the maximum value signal is the maximum envelope of the received signal as shown in Figure 3 A.
related to L 1 , whereas the minimum value signal is the minimum envelope L 2
is related to.
かかる最大値信号と最小値信号とが差動演算器
８に与えられる結果、第４図ロに示す如き雑音成
分が除去された差動出力が得られる。 As a result of applying the maximum value signal and minimum value signal to the differential arithmetic unit 8, a differential output from which noise components have been removed as shown in FIG. 4B is obtained.
この差動出力は次段の比較回路９に与えられ
る。比較回路９は受信信号の大きさに応じて予め
設定されている設定レベルと前記差動出力を比較
する。その結果、第４図１１に示すように、例え
ば金属板が２枚であることを示す検出信号が比較
回路９から出力される。 This differential output is given to the comparison circuit 9 at the next stage. The comparison circuit 9 compares the differential output with a setting level that is preset according to the magnitude of the received signal. As a result, as shown in FIG. 4, a detection signal indicating that there are two metal plates, for example, is output from the comparison circuit 9.
尚、上述の実施例において、リセツトパルス及
びサンプリングパルスの周波数は発振器３の発振
周波数と同じであるとして説明したが、この発明
はこれに限られるものでなく、受信信号と雑音成
分との分解能との関連において任意に定め得るも
のである。 In the above embodiment, the frequency of the reset pulse and the sampling pulse were explained as being the same as the oscillation frequency of the oscillator 3, but the present invention is not limited to this. It can be determined arbitrarily in relation to
ｆ 発明の効果
この発明は、受信信号から最大値信号と最小値
信号を抽出し、両信号の差動出力と設定レベルと
を比較することにより金属板の２枚送りを検出す
るものであるから、外部磁界等の影響に基づく雑
音成分を有効に除去できる。それ故、この発明に
係る２枚送り検出器は従来器に比較し、誤動作が
たいへん少いという優れた効果を有するものであ
る。f. Effect of the Invention This invention detects the feeding of two metal plates by extracting the maximum value signal and the minimum value signal from the received signal and comparing the differential output of both signals with the set level. , noise components due to the influence of external magnetic fields etc. can be effectively removed. Therefore, the double-sheet feed detector according to the present invention has an excellent effect of significantly reducing malfunctions compared to conventional devices.
第１図は従来の２枚送り検出器の動作波形図、
第２図はこの発明に係る２枚送り検出器の一実施
例の構成を略示したブロツク図、第３図及び第４
図は第２図に示した２枚送り検出器の動作波形図
である。
１……送信コイル、２……受信コイル、３……
発振器、４……同期パルス発生回路、５……最大
値保持回路、６……最小値保持回路、７Ａ，７Ｂ
……サンプル保持回路、８……差動演算器、９…
…比較回路。
Figure 1 is an operating waveform diagram of a conventional two-sheet feed detector.
FIG. 2 is a block diagram schematically showing the configuration of an embodiment of the two-sheet feed detector according to the present invention, and FIGS.
This figure is an operation waveform diagram of the two-sheet feed detector shown in FIG. 2. 1... Transmitting coil, 2... Receiving coil, 3...
Oscillator, 4... Synchronous pulse generation circuit, 5... Maximum value holding circuit, 6... Minimum value holding circuit, 7A, 7B
...Sample holding circuit, 8...Differential arithmetic unit, 9...
...comparison circuit.
Claims (1)
から発せられた交番磁界に基づく電磁誘導作用に
よつて受信コイルに誘起される受信信号の大きさ
から金属板の枚数を検出する２枚送り検出器にお
いて、前記受信信号から、その最大包絡線に関連
した最大値信号と最小包絡線に関連した最小値信
号とを抽出し、前記最大値信号と最小値信号に基
づく差動出力と設定レベルとを比較することによ
り金属板の枚数を検出することを特徴とする２枚
送り検出器。1. In a two-sheet feeding detector that includes a transmitting coil and a receiving coil and detects the number of metal plates from the magnitude of a received signal induced in the receiving coil by electromagnetic induction based on an alternating magnetic field emitted from the transmitting coil. , extracting a maximum value signal related to the maximum envelope and a minimum value signal related to the minimum envelope from the received signal, and comparing the differential output based on the maximum value signal and the minimum value signal with a set level. A two-sheet feed detector characterized by detecting the number of metal plates by.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57222820A JPS59114247A (en) | 1982-12-17 | 1982-12-17 | Double sheet feed detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57222820A JPS59114247A (en) | 1982-12-17 | 1982-12-17 | Double sheet feed detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59114247A JPS59114247A (en) | 1984-07-02 |
| JPH0134904B2 true JPH0134904B2 (en) | 1989-07-21 |
Family
ID=16788416
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57222820A Granted JPS59114247A (en) | 1982-12-17 | 1982-12-17 | Double sheet feed detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59114247A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2641591B2 (en) * | 1990-03-22 | 1997-08-13 | 日本精密電気株式会社 | Thin plate overlap detector |
| JP3519806B2 (en) * | 1994-11-29 | 2004-04-19 | 株式会社小野測器 | Thickness discriminator |
| JP5556419B2 (en) * | 2010-06-22 | 2014-07-23 | マツダ株式会社 | Blank number discrimination device for molding and discrimination method thereof |
-
1982
- 1982-12-17 JP JP57222820A patent/JPS59114247A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59114247A (en) | 1984-07-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4883264A (en) | Bill disbursing system | |
| US3717818A (en) | Instantaneous voltage detector | |
| EP0308073B1 (en) | System for detecting stray metal in articles | |
| EP0216128B1 (en) | Synchronous detector | |
| JPH0134904B2 (en) | ||
| JPS5940287A (en) | Apparatus for detecting metal | |
| KR101083679B1 (en) | Digitizer | |
| JPH0229997B2 (en) | ||
| JPH0411187Y2 (en) | ||
| RU2216028C2 (en) | Metal detector | |
| KR900701086A (en) | Magnetic flux calculation method of induction motor | |
| JPH03156629A (en) | Coordinate input device | |
| JPS5953292U (en) | Metal detector self-diagnosis circuit | |
| JP2674012B2 (en) | Metal detector | |
| KR100928532B1 (en) | Pickup device for metal body detection using Hall element | |
| JPS6143826B2 (en) | ||
| SU1130886A1 (en) | Device for counting metal items | |
| SU1748045A1 (en) | Device for ultrasonic control of metals | |
| JPH04122883A (en) | Metal detection method and apparatus | |
| SU949600A1 (en) | Pulse eddy-current metal finder | |
| JPS56122913A (en) | Coordinate reader | |
| JPS63185763A (en) | Printing device | |
| JPH05264308A (en) | Electromagnetic flowmeter | |
| JPS6024485A (en) | Metal detector | |
| JPH0712953A (en) | Metal detector |