JPS62173119A - Wire electric discharge machine - Google Patents
Wire electric discharge machineInfo
- Publication number
- JPS62173119A JPS62173119A JP1368386A JP1368386A JPS62173119A JP S62173119 A JPS62173119 A JP S62173119A JP 1368386 A JP1368386 A JP 1368386A JP 1368386 A JP1368386 A JP 1368386A JP S62173119 A JPS62173119 A JP S62173119A
- Authority
- JP
- Japan
- Prior art keywords
- wire electrode
- wire
- contactor
- current
- current supply
- 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.)
- Pending
Links
- 238000003825 pressing Methods 0.000 claims description 19
- 238000009763 wire-cut EDM Methods 0.000 claims description 7
- 238000000034 method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000009760 electrical discharge machining Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000007514 turning Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H7/00—Processes or apparatus applicable to both electrical discharge machining and electrochemical machining
- B23H7/02—Wire-cutting
- B23H7/08—Wire electrodes
- B23H7/10—Supporting, winding or electrical connection of wire-electrode
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明はワイヤ放電加工装置に関し、特に、ワイヤ放電
加工装置のワイヤ電極へ通電する通電接触子に関連する
ものである。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a wire electrical discharge machining device, and particularly to a current-carrying contact for supplying current to a wire electrode of the wire electrical discharge machining device.
従来の技術
第4図は、従来のワイヤ放電加I H置におけるワイヤ
電極への通電方式を示す要部説明図で、F〕はワイヤ電
極、Wは被加工物のワーク、1はライ1ン電極Pへ電力
を供給する通電接触子、2はワイA7電1U Pを保持
しガイドするガイド、3.4はワイヤ電44iPをガイ
ドするガイドローラ、5はワイヤを供給するワイヤ供給
ボビン、6はワイ\?電極Pが断線したとき、その断線
を検出するリミットスイッチであり、ワイヤ電極Pはワ
イヤ供給ボビン5からガイドローラ4.3でガイドされ
、通電接触子1と圧接し、ざらにガイド2でガイドされ
ワークW中を通り図示しない通電接触子、下ガイド及び
ガイドローラでガイドされてワイヤ巻取ボビンに巻き取
られるようになっている。ワイヤ電極Pは所定のテンシ
ョンをかけた状態で第4図で示ず例では上から下へ送行
しながら、通電接触子1とワークW間に電圧を印加する
ことによりワイヤ電+4i PとワークW間に電圧を印
加してワイA?電14iPとワークW間に放電を生じせ
しめ、ワークWを加工するものである。又、リミットス
イッチ6は、ワイヤ電極Pの断線を検出するもので、加
工中にワイヤ電極Pが断線すると、テンションがかけら
れていたワイヤ?Iff 4(x Pはたわみを生じる
が、そのたわみを検出し、ワイヤ電極Pの117i線を
検出するものである。Conventional technology Fig. 4 is an explanatory diagram of the main parts showing the method of energizing the wire electrode in a conventional wire discharge IH system, where F] is the wire electrode, W is the workpiece, and 1 is the line 1 line. A current-carrying contactor that supplies power to the electrode P; 2 is a guide that holds and guides the wire A7 wire 1U P; 3.4 is a guide roller that guides the wire wire 44iP; 5 is a wire supply bobbin that supplies the wire; 6 is a Wai\? This is a limit switch that detects the disconnection when the electrode P is disconnected. The wire passes through the workpiece W, is guided by a current-carrying contact, a lower guide, and a guide roller (not shown), and is wound onto a wire winding bobbin. The wire electrode P is fed under a predetermined tension from top to bottom in the example not shown in FIG. By applying a voltage between them? A discharge is generated between the electric current 14iP and the workpiece W to process the workpiece W. Further, the limit switch 6 is for detecting a break in the wire electrode P, and if the wire electrode P is broken during processing, the wire that was under tension will be removed. Iff 4(x P causes a deflection, but the deflection is detected and the 117i line of the wire electrode P is detected.
発明が解決しようとする問題点
上)ホしたような従来の/+5[電加工装置において、
加]二時にワイヤ電極Pが断線したとき、テンションを
かけられて走行していたワイヤ電極Pは第4図破線で示
すように、テンションがかからないことによりたわみが
生じ通電接触子1から離れる。Problems to be Solved by the Invention) In the conventional /+5
When the wire electrode P breaks at two o'clock, the wire electrode P, which was running under tension, bends due to the lack of tension and separates from the current-carrying contact 1, as shown by the broken line in FIG.
一方、リミットスイッチ6はワイヤ?ff1UPのたわ
みによりワイヤ電極]〕の断線を検出して、この信号に
よりワークWと通電接触子1間の電圧印加をオフにする
が、リミットスイッチ6がワイヤ電極Pの断線を検出し
通電接触子1への通電をオフにするまで時間遅れがあり
、そのため、ワイヤ電極Pが通電接触子1から離れると
き通電接触子1とワイヤ電極13間にfil電が生じ、
この放電により、放電が生じたワイヤ電極Pの個所に凹
状の1具がつく。On the other hand, is limit switch 6 a wire? A break in the wire electrode] is detected by the deflection of ff1UP, and this signal turns off the voltage application between the workpiece W and the current-carrying contact 1.However, the limit switch 6 detects the break in the wire electrode P and turns off the current-carrying contact. There is a time delay until the energization to 1 is turned off, so when the wire electrode P separates from the energizing contact 1, a filtration occurs between the energizing contact 1 and the wire electrode 13,
Due to this discharge, a concave portion is formed at the location of the wire electrode P where the discharge occurred.
その結果、再麿ワイV電極Pを結線Jる場合、ワイヤ電
極間
電I41iP上の傷かガイド2にひっかかり、通づこと
が難しく、特にワイヤ電極Pを自動送給するときなどは
、自動送給ができなくなる。As a result, when connecting the wire V electrode P, it is difficult to pass the wire because it gets caught in the guide 2 due to scratches on the wire electrode I41iP, and especially when the wire electrode P is automatically fed, I will not be able to pay my salary.
例えば、上記ガイド2がダイス状のものであると、ワイ
ヤ電極Pを通づダイス状ガイド2のクリアランスは5μ
〜10μであるので、ワイヤ電極に上記のような傷がつ
くと該傷がガイド2に係合して通すことができなくなる
ものである。又、放電が生じると通電接触子1にも傷が
つぎ、通電接触子1の寿命を短くする。For example, if the guide 2 is dice-shaped, the clearance of the dice-shaped guide 2 through which the wire electrode P passes is 5μ.
~10μ, so if the wire electrode is scratched as described above, the scratch will engage the guide 2 and will not be able to pass through. Moreover, when discharge occurs, the current-carrying contact 1 is also damaged, which shortens the life of the current-carrying contact 1.
本発明は上記問題点を解決しようとするもので、ライ1
フ電極が判断したとき、ワイヤ電極と通電接触子間の放
電を防止しワイヤ電極及び通電接触子に爛をつけないよ
うにするものである。The present invention is an attempt to solve the above problems.
This prevents discharge between the wire electrode and the current-carrying contact and prevents the wire electrode and the current-carrying contact from becoming eroded.
問題点を解決するための手段
上記問題点を解決するために、本発明は、ワイヤ電極に
電力を供給する通電接触子に対し、ワイヤ電極を押圧す
る押圧部材を設けることにより上記間i!1′1点を解
決した。Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a pressing member for pressing the wire electrode on the current-carrying contact that supplies power to the wire electrode. 1'1 point resolved.
作 用
fノイ曳7電(和は一]二足通電接触了と押圧部材によ
り挟持されているから、ワイヤ電極間
イヤ電1引が通電接触子と離れることはないので、通電
接触子とワイヤ電極間でtIi電が生じることらなくワ
イr電(参に傷がつくこともない。Action f Noi Hiki 7 Electric (Japanese is one) Since the wire is held between the two energized contacts and the pressing member, the wire between the electrodes and the energized contact will not be separated from the energized contact, so the energized contact and the wire There is no generation of tIi electricity between the electrodes, and there is no damage to the wire.
実施例
第1図は本発明の一実施例の片部の一部断面正面図、第
2図は第1図の右側面図、第3図は同実施例の押圧部l
の要部断面図であり、10はワイヤ電極Pに通電するた
めの取付板16に固着された通電接触子、11は取付板
16に固着されたワイiy ?ffl極Pをガイドする
ガイド、12は取付板16に固着されたノズル、13は
ワイヤ電極Pを通電接触子10に押圧する押圧部材で、
該押圧部材13は、上記取付板16上のピン20に揺動
自在に一端が相打されたレバー14と、該レバー14の
他端に回転自在に固るされたローラとしてのベアリング
19、及び上記レバー14を押圧し、上記ベアリング1
9を通電接触子10に押圧しワイヤ電極Pを該通電接触
子間
15で構成され、該板ばね15は一端が取ト1仮16に
固6され、他端が上記レバー14を押圧している。Embodiment FIG. 1 is a partially sectional front view of a piece of an embodiment of the present invention, FIG. 2 is a right side view of FIG. 1, and FIG. 3 is a pressing part l of the same embodiment.
10 is a current-carrying contact fixed to the mounting plate 16 for energizing the wire electrode P, and 11 is a wire fixed to the mounting plate 16. A guide for guiding the ffl pole P; 12 is a nozzle fixed to the mounting plate 16; 13 is a pressing member for pressing the wire electrode P against the current-carrying contact 10;
The pressing member 13 includes a lever 14 whose one end is swingably hitched to a pin 20 on the mounting plate 16, a bearing 19 as a roller rotatably fixed to the other end of the lever 14, and Press the lever 14 and press the bearing 1.
9 is pressed against the current-carrying contact 10, and a wire electrode P is formed between the current-carrying contacts 15. One end of the plate spring 15 is fixed to the handle 1 temporary 16, and the other end is pressed against the lever 14. There is.
第3図に示づように、ローラとしてのベアリング19は
レバー14の先端に固着されたシ1?ノド・19に絶縁
ブツシュ18を介して固着されている。As shown in FIG. 3, a bearing 19 as a roller is fixed to the tip of the lever 14. It is fixed to the throat 19 via an insulating bushing 18.
この絶縁ブツシュ18を介して固着ザることは、ワイヤ
電14 Pに通電16場合、通常取fJ根16゜通電接
触子10を同電位にすることから、ローラとしてのベア
リング19を介してワイヤ電極Pに電流が流れることを
防止するためのもので、ベアリング19に電流が流れる
とベアリング19のノtのが短くなることから絶縁プッ
シュト8により絶縁したちので、レバー14を絶縁材で
構成したり、他の個所で絶縁しベアリング19に電流が
流れないようにすればよく、必ずしもシャフト・17と
ベアリング19聞に絶縁ブツシュ18を設けて絶縁しな
くてしよい。This fixation through the insulating bushing 18 means that when the wire electrode 14P is energized, the wire electrode 14P is normally held at the same potential as the current-carrying contact 10 through the bearing 19 as a roller. This is to prevent current from flowing through the bearing 19, and since the knot of the bearing 19 will be shortened when a current flows through the bearing 19, it is insulated by the insulating pushbutton 8, so the lever 14 is made of an insulating material. , it is sufficient to insulate other parts to prevent current from flowing to the bearing 19, and it is not necessarily necessary to provide an insulating bush 18 between the shaft 17 and the bearing 19 for insulation.
本実施例は以上のような構成になっているので、板ばね
15は常時レバー14を押圧し該レバー14をピン20
を中心に第1図中時計方向に付勢し、レバー14の先端
に固着されたベアリング19を通′ii接触了10に押
圧し、ワイヤT11Pを通電接触子10に押圧している
。Since this embodiment has the above-described configuration, the leaf spring 15 always presses the lever 14 and pushes the lever 14 toward the pin 20.
The bearing 19 fixed to the tip of the lever 14 is pressed clockwise in FIG.
放電加工時には、取付板16及び通電接触子10を介し
でワイヤ電極Pに通電されるが、その放電加工時におい
てワイヤ電極Pが断線したとき、ワイーyM極Pにかけ
られていたテンシ=+ンがなくなり、ワイヤ電!i P
はたわもうとするが、ワイヤ電極Pは通電接触子10と
ベアリング19′C−押圧挾持されているからワイヤ電
極Pと通電接触子10は離反せず、そのため、ワイヤ電
極1つの断線検出手段からの出力により通電接触子10
への通電がオフになることが遅れても、ワイヤ電極Pと
通電接触子10間に放電が生じることはなく、ワイヤ電
極P及び通電接触子が傷つけられることはない。During electric discharge machining, the wire electrode P is energized through the mounting plate 16 and the current-carrying contact 10, but when the wire electrode P is disconnected during electric discharge machining, the tension applied to the wire M pole P is Gone, wire electricity! iP
However, since the wire electrode P is pressed between the current-carrying contact 10 and the bearing 19'C, the wire electrode P and the current-carrying contact 10 do not separate from each other. The energizing contact 10 is activated by the output from
Even if there is a delay in turning off the energization, discharge will not occur between the wire electrode P and the current-carrying contact 10, and the wire electrode P and the current-carrying contact will not be damaged.
なお、通電接触子10と取付板16聞を絶縁し、通電接
触子10に直接電力を供給するようにすれば、必ずしも
ベアリング19とシVフト17間に絶縁ブツシュ18を
入れる必要もない。又、ワイヤ電IPを通電接触子10
に押圧するベアリング19は、回転自在のローうでもよ
く、ざらには、板ばねのようなもので押圧部材を構成し
直接ワイヤ電極]〕を通電接触子10に押圧するように
してもよい。しかし、この場合、押圧部材がワイヤ電極
の走行と共に回転しないから、効果は同じであるが、該
押圧部材とワイAν電極P間のFj 11!が大さくな
るという欠点がある。Note that if the current-carrying contact 10 and the mounting plate 16 are insulated and power is directly supplied to the current-carrying contact 10, it is not necessarily necessary to insert the insulating bush 18 between the bearing 19 and the shaft 17. In addition, the wire electric IP is connected to the current-carrying contact 10.
The bearing 19 that presses the wire electrode may be a rotatable rod, or it may be a plate spring or the like that constitutes a pressing member and presses the wire electrode directly against the current-carrying contact 10. However, in this case, since the pressing member does not rotate with the movement of the wire electrode, the effect is the same, but Fj 11! between the pressing member and the wire Aν electrode P. The disadvantage is that it becomes large.
さらに、押圧部材の通電接触子10にワイヤ電極Pを押
圧するローラをワイヤ電極F〕の走行方向には回転し、
逆方向には回転しないようなワンウェイクラッチや、該
C1−ラをIig着した回転軸につめ車を固着し、ワイ
ヤ電極Pの走行方向には該ローラを回転自在とし、逆方
向にはつめによってつ゛め車をロックして回転しないよ
うにしてもよい。Furthermore, the roller that presses the wire electrode P against the current-carrying contact 10 of the pressing member is rotated in the running direction of the wire electrode F],
A one-way clutch that does not rotate in the opposite direction or a ratchet wheel is fixed to the rotating shaft to which the C1-ra is attached, and the roller is rotatable in the running direction of the wire electrode P, and by the pawl in the opposite direction. The pawl wheel may be locked to prevent it from rotating.
このように1れば、ワイヤ電極Pの切断時にワイψT1
極Pがはねあがることを防止でき、ワイヤ電極[〕が通
電接触子、押圧部材間を抜けることはない。If it is 1 in this way, the wire ψT1 when cutting the wire electrode P
The pole P can be prevented from springing up, and the wire electrode [ ] will not fall out between the current-carrying contact and the pressing member.
発明の効果
以上jボベたJ:うに、本発明は、ワイヤ電極が放電加
工中に切断してbワイヤ電極が通電接触子から離れるこ
とはないから、ワイヤ電極と通電接触子間に放i、Tf
が生じることはなく、そのlζめワイヤ電極及び通電接
触子に放電による傷がつくことはないため、ワイヤ電極
を再びガイドに通ずとぎワイヤ電極がガイドにひっかか
ることはなくワイヤの自動結線が容易に行え得る。又、
通電接触子にも10がつかないから、長時間の使用を可
能とする。More than Effects of the Invention The present invention prevents the wire electrode from separating from the current-carrying contact due to breakage during electrical discharge machining, so that there is no discharge between the wire electrode and the current-carrying contact. Tf
This prevents the wire electrode and current-carrying contact from being damaged by discharge, so the wire electrode can be passed through the guide again and the wire electrode will not get caught in the guide, making it easy to wire the wire automatically. It can be done. or,
Since 10 is not attached to the current-carrying contact, it can be used for a long time.
第1図は本発明の一実施例の要部一部断面正面図、第2
図は第1図右側面図、第3図は同実施例における押圧部
材の要部断面口、第4図は従来の放電加工装置における
ワイヤ電極への通電方式を示す要部説明図である。
1.10・・・通電接触子、2.11・・・ガイド、6
・・・リミットスイッチ、13・・・押圧部材、14・
・・レバー、15・・・板ばね、16・・・取付板、1
7・・・シャフト、18・・・絶縁ブツシュ、19・・
・ベアリング。
第1図 第2図
第3図
第4図FIG. 1 is a partially sectional front view of the main part of an embodiment of the present invention, and FIG.
The drawings are a right side view of FIG. 1, FIG. 3 is a sectional view of a main part of a pressing member in the same embodiment, and FIG. 4 is an explanatory diagram of a main part showing a method of supplying current to a wire electrode in a conventional electrical discharge machining apparatus. 1.10... Current-carrying contact, 2.11... Guide, 6
...Limit switch, 13...Press member, 14.
... Lever, 15 ... Leaf spring, 16 ... Mounting plate, 1
7...Shaft, 18...Insulating bushing, 19...
·bearing. Figure 1 Figure 2 Figure 3 Figure 4
Claims (5)
を供給する通電接触子に対し、ワイヤ電極を押圧する押
圧部材を設けたことを特徴とするワイヤ放電加工装置。(1) A wire electrical discharge machining apparatus, characterized in that a pressing member for pressing the wire electrode is provided on a current-carrying contact that supplies power to the wire electrode.
る特許請求の範囲第1項記載のワイヤ放電加工装置。(2) The wire electrical discharge machining apparatus according to claim 1, wherein the pressing member is constituted by a rotatable roller.
可能なローラで構成されている特許請求の範囲第1項記
載のワイヤ放電加工装置。(3) The wire electrical discharge machining apparatus according to claim 1, wherein the pressing member is constituted by a roller that can rotate only in the feeding direction of the wire electrode.
いる特許請求の範囲第1項、第2項、又は第3項記載の
ワイヤ放電加工装置。(4) The wire electrical discharge machining apparatus according to claim 1, 2, or 3, wherein the pressing member is insulated from other members by an insulating member.
れ、他端にローラが固着されたレバーと、該レバーを押
圧し上記ローラを通電接触子に押圧する板ばねによって
構成されている特許請求の範囲第1項、第2項、第3項
、又は第4項記載のワイヤ放電加工装置。(5) The pressing member is comprised of a lever whose one end is pivotally attached to the mounting plate so as to be able to swing freely, and a roller is fixed to the other end, and a leaf spring which presses the lever and presses the roller against the current-carrying contact. A wire electrical discharge machining apparatus according to claim 1, 2, 3, or 4.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1368386A JPS62173119A (en) | 1986-01-27 | 1986-01-27 | Wire electric discharge machine |
PCT/JP1987/000050 WO1987004379A1 (en) | 1986-01-27 | 1987-01-26 | Wire-cut electric spark machine |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1368386A JPS62173119A (en) | 1986-01-27 | 1986-01-27 | Wire electric discharge machine |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS62173119A true JPS62173119A (en) | 1987-07-30 |
Family
ID=11839981
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1368386A Pending JPS62173119A (en) | 1986-01-27 | 1986-01-27 | Wire electric discharge machine |
Country Status (2)
Country | Link |
---|---|
JP (1) | JPS62173119A (en) |
WO (1) | WO1987004379A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IT1216025B (en) * | 1988-03-08 | 1990-02-22 | Jeabor S A | APPARATUS SUITABLE TO OPERATE, IN AN ALMOST INSTANT WAY, THE COMPLETE DESTRUCTION OF THE SYRINGE NEEDLE BY INJECTION, IMMEDIATELY AFTER THEIR USE. |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2067946B (en) * | 1980-02-14 | 1984-08-08 | Inoue Japax Res | Electrode holder-guidance assembly for wire-cut electrical machining |
JPS5761421A (en) * | 1980-09-30 | 1982-04-13 | Mitsubishi Electric Corp | Wire feeder for wire cut discharge worker |
JPS5761422A (en) * | 1981-07-30 | 1982-04-13 | Mitsubishi Electric Corp | Spark erosion machine with cutting wire |
JPS5962933U (en) * | 1982-10-18 | 1984-04-25 | 吉江 勝廣 | Wire cut electric discharge machining tool |
-
1986
- 1986-01-27 JP JP1368386A patent/JPS62173119A/en active Pending
-
1987
- 1987-01-26 WO PCT/JP1987/000050 patent/WO1987004379A1/en unknown
Also Published As
Publication number | Publication date |
---|---|
WO1987004379A1 (en) | 1987-07-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO1996012346A3 (en) | A protected switch | |
JPH01199726A (en) | Device for detecting and controlling wire tension and breaking of wire | |
JPS62173119A (en) | Wire electric discharge machine | |
KR930004011A (en) | Wire electrode positioning controller of wire cut electric discharge machine | |
US4862095A (en) | Wire electrode breakage detection method and apparatus | |
JPS6015360A (en) | Remaining wire detector | |
US2666313A (en) | Motor control system for knitting machines | |
JPH0217751Y2 (en) | ||
JP2004035211A (en) | Detection method for wire disconnection and wire end, and wire rewinding device | |
JPH037086Y2 (en) | ||
KR200172021Y1 (en) | Electrical magnetic table to prevent the twisting of strip | |
JP3082317B2 (en) | Disconnection detection device of wire electric discharge machine | |
US4674668A (en) | Wire supply monitor | |
JPH0893768A (en) | Usage of air bearing type separate roller | |
US10964661B2 (en) | Wire bonding apparatus, circuit for wire bonding apparatus, and method for manufacturing semiconductor device | |
JPS61234960A (en) | Corona discharge wire | |
GB186314A (en) | Improvements in and relating to electric arc welding apparatus | |
JPH0346342A (en) | Wire feed apparatus | |
JP3264741B2 (en) | Filler wire supply TIG welding equipment | |
JPH01138063A (en) | Method and device for starting arc of dc arc welding | |
KR0143947B1 (en) | Coil stripping device | |
US1187408A (en) | System of electric welding. | |
US449903A (en) | And william d | |
JPH01151972U (en) | ||
JPH022552Y2 (en) |