Electro-erosion machine tools and head assemblies therefor

• US 4,205,212 A
• Filed: 04/26/1977
• Issued: 05/27/1980
• Est. Priority Date: 08/20/1976
• Status: Expired due to Term

• Current Assignee: A.G. Fur Industrielle Elektronik Agie Losone B. Locarno
• Original Assignee: A.G. Fur Industrielle Elektronik Agie Losone B. Locarno
• Inventors: Kilcher, Beat, Sieg, Arno, Buhler, Ernst, Ullmann, Werner, Ruh, Herbert
• Primary Examiner(s): Reynolds, B. A.
• Assistant Examiner(s): Shaw, Clifford C.
• Application Number:
  US05/791,055
• Time in Patent Office: 1,127 Days
• Field of Search: 219/69 W, 219/69 V, 219/69 R, 219/69 M, 204/206, 204/211, 308/3 R, 308/5 R, 308/9, 308/237, 339/17 C, 339/255 R, 339/255 RT, 339/256 S, 339/117 P
• US Class Current: 219/69.12
• CPC Class Codes: B23H 7/10 Supporting, winding or electrical connection of wire-electrode

Abstract

A head assembly for an electro-erosion machine tool comprises, in a housing, a guide for guiding the moving filamentary or strip-form tool electrode and first contact means for supplying erosion energy to the electrode. The scavenging medium is fed into the housing so as to cool the contact means and guide, and leaves it by way of a nozzle through which also the electrode leaves the housing on its way to another head assembly arranged on the opposite side of the location where machining is performed, the scaverging medium being thereby fed to the machining location as an envelope coaxial to the electrode. Second contact means for contacting the workpiece to be machined are fixed to the nozzle and the connections to each contact means are arranged for low inductive energy loss.

Claims

1. Electro-erosion apparatus of the type in which an elongated tool electrode (1) is moved under tension between first and second head assemblies (5a, 5b) for performing an electro-erosion work process on a workpiece (2) wherein

the workpiece is disposed between said head assemblies,

each said head assemblies includes

means (300a, 300b) for making electrical contact to said electrode and each of said head assemblies further includes means directing scavenging fluid to the electro-erosion location working gap,

wherein each of said assemblies comprises a housing;

fluid inlet means (200a, 200b) leading to the interior of the respective housing for passing scavenging fluid (7a, 7b) to the respective interior of the respective housing to fill the respective housing;

an outlet nozzle (303) defining an opening between the interior and the exterior of the respective housing through which a tool electrode can pass from one housing to the other, and through which scavenging fluid also can pass from the interior of the respective housing as an envelope surrounding and in contact with said tool electrode, and being directed toward the workpiece;

electrical contacts (300a, 300b) mounted in the respective interior of the respective housing and being cooled by the scavenging fluid therein and in electrical contact engagement with said tool electrode;

and tool electrode guide means (100a, 100b) mounted in the interior of the respective housing, each guide means being cooled by the scavenging fluid within the respective housing and guiding said tool electrode in its path through said outlet means, at least one of said guide means comprising two support members (101,

     102), two parallel pivot pins (119) attached to respective ones of said support members, a first set of polygonal guide plates (115,

     116) rotatably mounted one above another on one of said pivot pins, and a second set of polygonal guide plates (117,

     118) rotatably mounted one above another on the other of said pivot pins, said plates being so arranged in relation to one another that edge portions thereof bound a space in which said tool electrode can be located so that said edge portions are in sliding contact with said tool electrode and such that, for each plate, there is another one of said plates which is at the same level on said pivot pins and which contacts said tool electrode on the opposite side thereof.

2. Apparatus according to claim 1 wherein said plates are triangular and they are in contact with said tool electrode at four locations symmetrically disposed around the periphery of said tool electrode.

3. Apparatus according to claim 1, wherein one of said support members is mounted within said housing for movement towards and away from said other support member and wherein said first head assembly includes a screw mounted in said housing opposite said one member so that it can be turned to adjust its spacing from said one member, and a spring arranged between said screw and said one member such that said spring biases the said one support member towards said other support member and said screw adjusts the biassing force of said spring.

4. Apparatus according to claim 1, wherein one of said support members is movably mounted and is able to be moved away from the other said support member to facilitate insertion therebetween of said tool electrode.

5. Apparatus in accordance with claim 1, wherein said two respective head assemblies are similar in structure.

6. Apparatus in accordance with claim 1, further comprising

a first electro-erosion power supply connection wire connected to said electrode contact of said first head assembly,

and a second electro-erosion power supply connection wire connected to said electrode contact of said second head assembly,

said first and second power supply connection wires operating independently of each other'"'"'s load fluctuations to prevent overloading of said electrode between said workpiece and said one electrode contact as a result of a change in loading of said electrode between said workpiece and the other electrode contact.

7. Apparatus according to claim 6, further including first and second connecting wires making contact with the workpiece,

wherein the first electro-erosion power supply connection wire connected to the electrode and the first workpiece connecting wire are twisted together,

and the second electro-erosion power supply connection wire connected to the electrode contact and the second workpiece connecting wire are twisted together,

whereby the effects of stray inductances are reduced.

8. Electro-erosion apparatus of the type in which an elongated tool electrode (1) is moved under tension between first and second head assemblies (5a,5b) for performing an electro-erosion work process on a workpiece (2) wherein

the workpiece is disposed between said head assemblies,

each said head assemblies includes

means (300a, 300b) for making electrical contact to said electrode and each of said head assemblies further includes means directing scavenging fluid to the electro-erosion locating working gap,

wherein each of said assemblies comprises a housing;

fluid inlet means (200a, 200b) leading to the interior of the respective housing for passing scavenging fluid (7a, 7b) to the respective interior of the respective housing to fill the respective housing;

an outlet nozzle (303) defining an opening between the interior and the exterior of the respective housing through which a tool electrode can pass from one housing to the other, and through which scavenging fluid also can pass from the interior of the respective housing as an envelope surrounding and in contact with said tool electrode, and being directed toward the workpiece;

electrical contacts (300a, 300b) mounted in the respective interior of the respective housing and being cooled by the scavenging fluid therein and in electrical contact engagement with said tool electrode;

and tool electrode guide means (100a, 100b) mounted in the interior of the respective housing, each guide means being cooled by the scavenging fluid within the respective housing and guiding said tool electrode in its path through said outlet means, at least one of said guide means comprising means defining a V-shaped notch, and a counter assembly comprising a support member (102), a pivot pin (119) attached to said support member for extending parallel to the axis of said tool electrode, and a set of triangular guide plates rotatably mounted one above another on said pivot pin, said plates being positioned in relation to one another and in relation to the V-shaped notch defining means so that edge portions of the plates and the sides of the notch bound a space in which said tool electrode can be located so that said edge portions and notch sides are in sliding contact with said tool electrode at four locations symmetrically disposed around the periphery of said tool electrode.

9. Apparatus in accordance with claim 8, wherein said two respective head assemblies are similar in structure.

10. Apparatus in accordance with claim 8, further comprising

a first electro-erosion power supply connection wire connected to said electrode contact of said first head assembly,

and a second electro-erosion power supply connection wire connected to said electrode contact of said second head assembly,

said first and second power supply connection wires operating independently of each other'"'"'s load fluctuations to prevent overloading of said electrode between said workpiece and said one electrode contact as a result of a change in loading of said electrode between said workpiece and the other electrode contact.

11. Apparatus according to claim 10, further including first and second connecting wires making contact with the workpiece,

wherein the first electro-erosion power supply connection wire connected to the electrode and the first workpiece connecting wire are twisted together,

and the second electro-erosion power supply connection wire connected to the electrode contact and the second workpiece connecting wire are twisted together,

whereby the effects of stray inductances are reduced.