Method and means for removing smoke from open arc welding operations

Claim 2

In a welding gun for self-shielded arc welding including an elongated electrode nozzle having a continuous longitudinal passage therethrough and a contact tip through which an arc welding electrode is adapted to be moved axially of the tip toward a workpiece to be welded while an arc is maintained between the end of the electrode and the workpiece, said arc generating heated fumes and smoke, and means including a source of vacuum for removing said fumes and smoke generated at the arc, the improvement comprising: said means including an exhaust tube having a first end communicating with said source and a second end open toward said workpiece, a shield member, means spacing said shield member from said contact tip in the direction toward said workpiece, said shield member having upper and lower surfaces with respect to said direction and an outer surface between said upper and lower surfaces, said upper surface of said shield member being spaced from said second end of said exhaust tube in said direction to define therewith a radial entrance to said exhaust tube generally transverse to said contact tip, the juncture between said upper and outer surfaces being shaped to facilitate eddy-free flow of fumes and smoke through said entrance, said shield member at said juncture having an outermost edge radially spaced from said contact tip such that the shield member prevents direct impingement of weld spatter on said second end of said exhaust tube, said shield member having an opening therethrough between said upper and lower surfaces, and an insert of electrically insulating material in said opening, said insert having a lower end spaced in said direction from said contact tip and having an electrode receiving aperture therethrough closely spaced radially from said electrode as it moves toward said workpiece, said insert closing said opening through said shield member radially outwardly of said electrode aperture to protect said contact tip from weld spatter and from the heat of the arc.

Claim 3

The improvement according to claim 1, wherein said outermost edge of said juncture is radially spaced from five-sixteenths to three-fourths inch from the axis of said contact tip and the juncture between said upper and outer surfaces is rounded and has a radius of from one-sixteenths to one-fourth inch.

Claim 4

The improvement according to claim 2, wherein said outer surface of said shield member tapers downwardly and inwardly at an angle of about 45* with respect to said upper surface, and said upper surface is spaced from said second end of said exhaust tube from one-sixteenth to one-half inch.

Claim 5

In a welding gun for self-shielded arc welding including an elongated electrode nozzle having a continuous longitudinal passage therethrough and a contact tip through which an arc welding electrode is adapted to be moved axially of the tip tOward a workpiece to be welded while an arc is maintained between the end of the electrode and the workpiece, said arc generating heated fumes and smoke, and means including a source of vacuum for removing said fumes and smoke generated at the arc, the improvement comprising: said means including an exhaust tube having a first end communicating with said source and a second end open toward said workpiece, a shield member, means spacing said shield member from said contact tip in the direction toward said workpiece, said shield member having upper and lower surfaces with respect to said direction and an outer surface between said upper and lower surfaces, said upper surface of said shield member being spaced from said second end of said exhaust tube in said direction to define therewith a radial entrance to said exhaust tube generally transverse to said contact tip, the juncture between said upper and outer surfaces being shaped to facilitate eddy-free flow of fumes and smoke through said entrance, said shield member at said juncture having an outermost edge radially spaced from said contact tip such that the shield member prevents direct impingement of weld spatter on said second end of said exhaust tube, said shield member having an opening therethrough between said upper and lower surfaces, and an insert of electrically insulating material in said opening and apertured to receive said electrode as it moves toward said workpiece, said insert protecting said contact tip from weld spatter and from the heat of the arc, said second end of said exhaust tube surrounding and being generally concentric with respect to said contact tip, and said second end of said exhaust tube and said upper surface of said shield member being located for ambient air, fumes and smoke drawn into said radial entrance to impinge on said contact tip.

Claim 6

In a welding gun for self-shielded arc welding including an elongated electrode nozzle having a continuous longitudinal passage therethrough and a contact tip through which an arc welding electrode is adapted to be moved axially of the tip tOward a workpiece to be welded while an arc is maintained between the end of the electrode and the workpiece, said arc generating heated fumes and smoke, and means including a source of vacuum for removing said fumes and smoke generated at the arc, the improvement comprising: said means including an exhaust tube having a first end communicating with said source and a second end open toward said workpiece, a shield member, means spacing said shield member from said contact tip in the direction toward said workpiece, said shield member having upper and lower surfaces with respect to said direction and an outer surface between said upper and lower surfaces, said upper surface of said shield member being spaced from said second end of said exhaust tube in said direction to define therewith a radial entrance to said exhaust tube generally transverse to said contact tip, the juncture between said upper and outer surfaces being shaped to facilitate eddy-free flow of fumes and smoke through said entrance, said shield member at said juncture having an outermost edge radially spaced from said contact tip such that the shield member prevents direct impingement of weld spatter on said second end of said exhaust tube, said shield member having an opening therethrough between said upper and lower surfaces, and an insert of electrically insulating material in said opening and apertured to receive said electrode as it moves toward said workpiece, said insert protecting said contact tip from weld spatter and from the heat of the arc, said second end of said exhaust tube surrounding and being generally concentric with respect to said contact tip, and said second end of said exhaust tube and said upper surface of said shield member being located for ambient air, fumes and smoke drawn into said radial entrance to impinge on said contact tip.

Claim 7

The improvement according to claim 4, wherein said second end of said exhaust tube is circular, said shield member is frusto-conical, and said outer surface tapers downwardly and inwardly from said upper surface, the radius of said outermost edge of said juncture being at least equal to the radius of the outermost edge of said second end of said exhaust tube.

Claim 8

The improvement according to claim 5, wherein the taper of said outer surface of said shield member is at an angle of about 45* with respect to said upper surface.

Claim 9

The improvement according to claim 4, wherein said exhaust tube includes a fixed portion terminating above said contact tip and a removable extension portion telescoped to said fixed portion and having a lower end defining said second end, said shield member being mounted on said lower end of said extension portion.

Claim 10

The improvement according to claim 7, wherein said outermost edge of said juncture is radially spaced from five-sixteenths to three-fourths inch from the axis of said contact tip, the juncture between said upper and outer surfaces is rounded and has a radius of from one-sixteenth to one-fourth inch, and said upper surface is spaced from said lower end of said extension portion from one-sixteenth to one-half inch.