Stud welding guns

Claim 2

An arc-welding gun comprising a hollow main body having a work-engaging end, means connecting the gun to a power source for providing a stud-welding arc, a retractable stud-gripping mechanism mounted in the body for yielding movement away from said end, a clutch means movable in the body and operable to lock said meChanism in fixed position relative to the work surface when said end and a stud held by the mechanism have been caused forcibly to engage the work surface, and power means operable thereafter further to retract the clutch mechanism and hence the stud a selected predetermined distance from said surface during arcing.

Claim 3

A gun as set forth in claim 1 wherein the clutch means comprises a radially expansible member for gripping a portion of the stud-gripping mechanism, and electromagnetic means for controlling operation of said member.

Claim 4

A gun as set forth in claim 2 wherein said member is in the form of an elastomeric ring circumferentially engageable with a cylindrical wall of said gripping mechanism.

Claim 5

A gun as set forth in claim 2 wherein said member is a V-shaped polyurethane band.

Claim 6

A gun as set forth in claim 4 wherein the electromagnetic means is a solenoid shiftable axially in the main body and energizable to cause its armature axially to compress said band and thereby lock it to said mechanism.

Claim 7

A gun as set forth in claim 1 wherein the clutch means comprises a solenoid operable axially in the body and energizable to squeeze an expansible band and thus lock the gripping mechanism axially with respect to the work surface, a second solenoid secured in the body and operatively connected to the first-mentioned solenoid, and control means for energizing the second solenoid after the first solenoid his been energized and during arcing.

Claim 8

A gun as set forth in claim 1 wherein the work-engaging end of the body includes a detachable ferrule assembly for axially receiving a stud to be welded and disposed to abut the work surface in the vicinity of the stud, and said stud-gripping mechanism comprises, in coaxial relation to the ferrule assembly, an axially split collet and a member coupled at one end to the collet and extending into the tool body, said member having at its inner end a tubular clutch portion arranged in telescoping relation to said clutch means.

Claim 9

An arc-welding gun comprising a hollow main body provided with a work-engaging ferrule end adapted to surround a stud or the like to be welded to a work surface, the gun being connectable to a power source for providing welding current, retractable mechanism mounted on the gun body including a stud-gripping collet initially arranged to hold a weldable end of the stud projecting beyond the ferrule end and adapted to move the stud axially in the ferrule end, a spring for urging said mechanism toward the ferrule end, said mechanism including a clutch portion axially disposed in the body, a clutch-operating solenoid, a radially expansible clutch band cooperative with said clutch portion and responsive to energization of the clutch solenoid to lock said retractable mechanism in an axial position determined by thrusting the stud gripped by the collet against the work surface until both the weldable end of the stud and the ferrule end abut said surface, and an actuating solenoid mounted in the body and energizable for effecting retraction of the stud-gripping mechanism and said stud against the influence of said spring, said actuating solenoid being effectively operable only after operation of the clutch-operating solenoid to establish a predetermined arc gap for the weldable end of the stud with respect to said surface.

Claim 10

An arc-welding gun comprising a hollow main body provided with a work-engaging ferrule end adapted to surround a stud or the like to be welded to a work surface, the gun being connectable to a power source for providing welding current, retractable mechanism mounted on the gun body including a stud-gripping collet initially arranged to hold a weldable end of the stud projecting beyond the ferrule end and adapted to move the stud axially in the ferrule end, a spring for urging said mechanism toward the ferrule end, said mechanism including a clutch portion axially disposed in the body, a clutch-operating solenoid, a radially expansible clutch band cooperative with said clutch portion and responsive to energization of the clutch solenoid to lock said retractable mechanism in an axial position determined by thrusting the stud gripped by the collet against the work surface until both the weldable end of the stud and the ferrule end abut said surface, and an actuating solenoid mounted in the body and energizable for effecting retraction of the stud-gripping mechanism and said stud against the influence of said spring, said actuating solenoid being effectively operable only after operation of the clutch-operating solenoid to establish a predetermined arc gap for the weldable end of the stud with respect to said surface.

Claim 11

A gun as set forth in claim 8 wherein means is provided for adjusting the axial position of the actuating solenoid to modify said arc gap.

Claim 12

An arc-welding gun comprising a body provided with a work-engaging end, a stud-holding collet initially arranged to grip a stud and hold its weldable end axially projecting beyond said body end, means for striking a welding arc between the stud and a work surface, a member axially shiftable in the body and coupled to the collet, a spring for resisting relative axial displacement of the collet and said member relative to the body, a clutch frictionally engageable with said member to lock it in a normalized stud length position relative to said work surface when the weldable stud end abuts the work surface and said end of the body is also urged against said surface, and electromagnetic means mounted in the body and operative after the clutch has locked onto said member to retract the locked member and hence the stud a predetermined distance from the surface.

Claim 13

An arc-welding gun comprising a body provided with a work-engaging end, a stud-holding collet initially arranged to grip a stud and hold its weldable end axially projecting beyond said body end, means for striking a welding arc between the stud and a work surface, a member axially shiftable in the body and coupled to the collet, a spring for resisting relative axial displacement of the collet and said member relative to the body, a clutch frictionally engageable with said member to lock it in a normalized stud length position relative to said work surface when the weldable stud end abuts the work surface and said end of the body is also urged against said surface, and electromagnetic means mounted in the body and operative after the clutch has locked onto said member to retract the locked member and hence the stud a predetermined distance from the surface.

Claim 14

In a stud-welding gun having a body provided with a work-engaging end, means for connecting the gun to a power source for providing a welding arc, a yieldably retractable stud-gripping mechanism, a solenoid energizable to yieldably retract the stud-gripping mechanism in the body and a stud gripped by said mechanism from a work surface, a solenoid-operated clutch interposed between said mechanism and said retractive solenoid for fixing the axial position of said mechanism when the stud and said body contact the work surface, and a control means for effectively locking the solenoid-operated clutch to the gripping mechanism before the retracted solenoid is energized whereby the stud is retracted a predetermined distance from said surface during arcing.

Claim 15

In a stud-welding gun having a body provided with a work-engaging end, means for connecting the gun to a power source for providing a welding arc, a yieldably retractable stud-gripping mechanism, a solenoid energizable to yieldably retract the stud-gripping mechanism in the body and a stud gripped by said mechanism from a work surface, a solenoid-operated clutch interposed between said mechanism and said retractive solenoid for fixing the axial position of said mechanism when the stud and said body contact the work surface, and a control means for effectively locking the solenoid-operated clutch to the gripping mechanism before the retracted solenoid is energized whereby the stud is retracted a predetermined distance from said surface during arcing.

Claim 16

In a gun for arc-welding studs having lengths to be normalized, a hollow main body provided with a work-engaging end, a stud-gripping collet for moving a stud to be welded and movable in coaxial relation to said work-engaging end, retractable mechanism in the body coupled to the collet, spring means urging the collet to project a stud gripped thereby beyond said work-engaging end, an expandable clutch band axially shiftable in the body and arranged to cooperate with a portion of said mechanism, a solenoid mounted for limited axial movement in the body and having its armature operatively connected to the clutch band, a second and larger solenoid secured in the body and having its armature operatively coupled to the smaller solenoid, and electrical control means for energizing the smaller solenoid before the larger solenoid is energized.

Claim 17

In a gun for arc-welding studs having lengths to be normalized, a hollow main body provided with a work-engaging end, a stud-gripping collet for moving a stud to be welded and movable in coaxial relation to said work-engaging end, retractable mechanism in the body coupled to the collet, spring means urging the collet to project a stud gripped thereby beyond said work-engaging end, an expandable clutch band axially shiftable in the body and arranged to cooperate with a portion of said mechanism, a solenoid mounted for limited axial movement in the body and having its armature operatively connected to the clutch band, a second and larger solenoid secured in the body and having its armature operatively coupled to the smaller solenoid, and electrical control means for energizing the smaller solenoid before the larger solenoid is energized.