Contact tip for use in gas metal-arc welding
View Patent ↗A contact tip ( 1 ) for gas metal-arc welding comprising: A body ( 3 ) of a metal material with a tubular base portion ( 4 ) and two or more fingers ( 5 a, 5 b ) extending in the axial direction from a front end of the base portion; At least one wire-feed conduit ( 7 ) extending axially through the body, in which a welding wire is to be received and fed; slots ( 10 a, 10 b ) arranged between the fingers in order to space these apart, and A spring means ( 11 ) surrounding the fingers and exerting a radially acting spring force on the fingers of such strength that the fingers, when cool, are kept spaced apart, such that no pressure will be exerted on the casing surface of a welding wire introduced in the wire-feed conduit, and when heated to a temperature above the softening temperature of the metal material, are compressed by the spring force radially inward in order to exert pressure on the casing surface of a welding wire received in the wire-feed conduit.
1. A contact tip for use in gas metal-arc welding, the contact tip comprising:
a body comprising an electrically conductive first metallic material, wherein the body has a tubular base portion and two or more fingers connected to the base portion and extending in an axial direction from a front end of the base portion, wherein at least one of the fingers includes a planar side surface, the planar side surface extending in the axial direction;
at least one wire-feed conduit extending axially through the body in which a welding wire is to be received and advanced, the wire-feed conduit having an inlet opening at a rear end of the contact tip and an outlet port at a front end of the contact tip between the fingers, and
slots arranged in the body between the fingers in order to separate the fingers from one another, whereby each slot extends in the axial direction from the body's base portion and to the outlet port;
wherein the contact tip includes a spring surrounding the fingers, wherein the spring includes a second metallic material having a softening temperature above a softening temperature of the first metallic material and is arranged to exert a radially inward spring force on the fingers, wherein the fingers at a temperature substantially below the softening temperature of the first metallic material of the body are spaced apart such that a casing surface of a welding wire is adjustable in the wire-feed conduit, and wherein the fingers at a temperature above the softening temperature of the first metallic material of the body during operation are compressed by the radially inward spring force to exert pressure against the casing surface of the welding wire introduced in the wire-feed conduit, and wherein the spring has an opening in a circumferential direction of the spring, the opening being disposed at the planar side surface of the at least one of the fingers.
2. The contact tip according to claim 1 , wherein the spring is disposed in a groove disposed on the outside of the fingers.
3. The contact tip according to claim 2 , wherein the spring is a volute spring in the shape of an open ring.
4. The contact tip according to claim 1 , wherein the spring is a bimetallic element.
5. The contact tip according to claim 1 , wherein the softening temperature of the second metallic material of the spring is at least two times above the softening temperature of the first metallic material from which the contact tip body is made.
6. The contact tip according to claim 1 , wherein the spring is arranged around the fingers at a front portion thereof.
7. The contact tip according to claim 1 , wherein the fingers are two in number and spaced apart by two slots opposingly arranged on opposite sides of the wire-feed conduit.
8. The contact tip according to claim 1 , wherein the slot has a width (w) corresponding to 25-90% of the diameter (d) of the wire-feed conduit.
9. The contact tip according to claim 1 , wherein the body is made of a copper alloy.
10. A contact tip for use in gas metal-arc welding, the contact tip comprising:
a body comprising a metallic material, wherein the body has a tubular base portion and two or more fingers connected to the base portion and extending in an axial direction from a front end of the base portion, wherein at least one of the fingers includes a recess cutting into a tubular surface of the fingers to form a planar surface, the planar surface extending in the axial direction;
at least one wire-feed conduit extending axially through the body in which a welding wire is to be received and advanced, the wire-feed conduit having an inlet opening at a rear end of the contact tip and an outlet port at a front end of the contact tip between the fingers;
slots arranged in the body between the fingers in order to separate the fingers from one another, whereby each slot extends in the axial direction from the body's base portion and to the outlet port; and
a spring surrounding the fingers and arranged to exert a radially inward spring force on the fingers, wherein the fingers at a temperature substantially below a softening temperature of the metallic material of the body are spaced apart such that a casing surface of a welding wire is adjustable in the wire-feed conduit, and wherein the fingers at a temperature above the softening temperature of the metallic material of the body during operation are compressed by the radially inward spring force to exert pressure against the casing surface of the welding wire introduced in the wire-feed conduit,
wherein the spring includes an opening in a circumferential direction of the spring, the opening being disposed at the planar surface of the at least one of the fingers.
11. The contact tip according to claim 10 , wherein the spring is disposed in a groove disposed on the outside of the fingers.
12. The contact tip according to claim 10 , wherein the spring is a volute spring in the shape of an open ring.
13. The contact tip according to claim 10 , wherein the metallic material of the body is a first metallic material, and the spring includes a second metallic material with a softening temperature above the softening temperature of the first metallic material of the contact tip body.
14. The contact tip according to claim 13 , wherein the softening temperature of the second metallic material of the spring is at least two times above the softening temperature of the first metallic material of the contact tip body.
15. The contact tip according to claim 10 , wherein the spring is a bimetallic element.
16. The contact tip according to claim 10 , wherein the spring is arranged around the fingers at a front portion thereof.
17. The contact tip according to claim 10 , wherein the fingers are two in number and spaced apart by two slots opposingly arranged on opposite sides of the wire-feed conduit.
18. The contact tip according to claim 10 , wherein the slot has a width (w) corresponding to 25-90% of the diameter (d) of the wire-feed conduit.
19. The contact tip according to claim 10 , wherein the body is made of a copper alloy.