RETAINING HEAD AND CONTACT TIP FOR CONTROLLING WIRE CONTOUR AND CONTACTING POINT FOR GMAW TORCHES

• US 20090152255A1
• Filed: 05/22/2008
• Published: 06/18/2009
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Ma, Tiejun, Pinsonneault, Paul-David, Jaeger, Thomas
• Granted Patent: US 8,450,646 B2
• Time in Patent Office: Days
• US Class Current: 219/137.610
• CPC Class Codes: B23K 9/123 Serving also as contacting devices supplying welding current to an electrode
• CPC Class Codes: B23K 9/295 using consumable electrode-wire

Abstract

A retaining head for a MIG welding device includes a contact tip mounting end, an opposite retaining head mounting end, and a throughbore extending from one of the ends to the other end. A deflector is disposed along the throughbore and is adjustable for imparting a bend in welding wire passing through the throughbore. The deflector provides a straight wire contour for the welding wire that is fed out of the welding torch, while maintaining sufficient contact force between the welding wire and the contact tip. The deflector also reduces the effect of wire twist on the contact point between the welding wire and the contact tip.

Claims

1. A retaining head for a MIG welding device, said retaining head comprising:

a contact tip mounting end, an opposite retaining head mounting end, and a throughbore extending from one said end to said other end; and

a deflector disposed along said throughbore for imparting a bend in welding wire passing through said throughbore.

2. The retaining head of claim 1, wherein said throughbore includes a reduced diameter portion between said retaining head mounting end and said contact tip mounting end;

and

a liner extending into said retaining head biased in part away from a centerline of said throughbore by said deflector and guided back toward said centerline by said reduced diameter portion, thereby imparting a bend in welding wire fed through said liner.

3. The retaining head of claim 1, wherein said deflector is one of a set screw, a pin, a roller, an insert, and a spring guide.

4. The retaining head of claim 1, wherein said deflector is one of a pair of pins and a pair of rollers.

5. The retaining head of claim 4, wherein said one of said pair of pins and pair of rollers directly guides said welding wire.

6. The retaining head of claim 1, wherein said deflector bends said welding wire at an obtuse angle.

7. The retaining head of claim 1 in combination with a contact tip having a mounting end and an opposite tip end;

said contact tip having a stepped throughbore extending between said mounting end and said tip end;

said stepped throughbore being defined by a contact bore at said tip end and a spaced bore at said mounting end of a greater diameter than said contact bore at said tip end.

8. The retaining head of claim 7, wherein said welding wire contacts said throughbore of said contact tip in said contact bore.

9. The retaining head of claim 1, wherein said retaining head throughbore includes an extended spaced bore near the contact tip mounting end.

10. A method of advancing a welding wire through a MIG torch including the steps of:

mounting a retaining head on a MIG torch, said retaining head having a contact tip mounting end, an opposite retaining head mounting end, and a throughbore extending from one said end to said other end;

disposing a deflector along said throughbore for imparting a bend in welding wire passing through said throughbore; and

feeding welding wire through said retaining head.

11. The method of claim 10, including the step of:

mounting a contact tip on said retaining head, said contact tip having a mounting end, an opposite tip end, and a stepped throughbore extending between said mounting end and said tip end, said stepped throughbore being defined by a contact bore at said tip end and a spaced bore of a greater diameter than said contact bore at said tip end;

wherein welding wire fed through said retaining head contacts said throughbore of said contact tip in said contact bore.

12. An assembly for a welding torch, the assembly comprising:

a retaining head mountable on a welding torch, said retaining head having front and rear ends and a throughbore extending axially between said front and rear ends;

said throughbore including a reduced diameter portion between said front and rear ends;

a deflector extending into said throughbore of said retaining head for contact with a liner of the welding torch;

a contact tip mounted in said retaining head throughbore and extending from said retaining head front end;

said contact tip including a body and a throughbore extending axially through said body, said throughbore having a wide diameter inlet, a large diameter portion adjacent said inlet, and a small diameter portion stepped from said large diameter portion;

said deflector pushing said liner away from a centerline of said throughbore, and said liner being guided back toward said centerline by said reduced diameter portion of said retaining head throughbore, thereby imparting a bend in welding wire fed through said liner such that said welding wire is bent by said liner at two points and bent by said contact tip at one point in said small diameter portion.

13. The assembly of claim 12, wherein said deflector is one of a set screw, a pin, a roller, an insert, and a spring guide.

14. The assembly of claim 12, wherein said deflector is one of a pair of pins and a pair of rollers.

15. The assembly of claim 14, wherein said one of said pair of pins and pair of rollers directly guides said welding wire.

16. The assembly of claim 12, wherein the welding wire exiting from said contact tip has a wire cast of 60 inches or more.