Welding method and apparatus suitable for forming links in jewelry

Claim 2

Welding apparatus of the type comprising electrodes for subjecting a workpiece to a welding current at a joint to be welded and pressing means for maintaining a pressing force on the workpiece through the joint while current is applied, the welding apparatus comprising: opposing ram carriers; opposing electrode rams, one electrode ram mounted to each carrier and spring biased relative to the carrier toward the other electrode ram; drive means for simultaneously driving opposing ram carriers toward each other to press the workpiece between the electrode rams such that each ram retracts against the spring bias to cushion the electrode ram as it contacts the workpiece and thereafter maintain predetermined pressing force against the workpiece, the electrode rams providing the sole clamping force on the workpiece through the joint to be welded; sensing means associated with each of the electrode rams for sensing the time at which the first of the opposing electrode rams applies a predetermined pressure against the workpiece; and an electrical current source for applying a welding current between the electrode rams in response to the sensing means such that welding current is applied as a predetermined clamping force is applied to the workpiece by an electrode ram.

Claim 3

Welding apparatus as claimed in claim 1 wherein the sensing means comprises a limit switch associated with each electrode carrier which is triggered by movement of the electrode relative to the electrode carrier.

Claim 4

Welding apparatus as claimed in claim 1 comprising pneumatic drive means.

Claim 5

Welding appartus as claimed in claim 1 wherein the drive means comprises a common belt or chain drive for the electrode rams.

Claim 6

In a link forming apparatus of the type having means for feeding a U-shaped wire segment to a forming station and for retaining the wire segment against lateral movement in the forming station and an anvil movable against the open end of the U-shaped wire at the forming station to close the wire into a wire link, the improvement comprising: opposing ram carriers; opposing electrode rams, one electrode ram mounted to each carrier and spring biased relative to the carrier toward the other electrode ram; drive means for simultaneously driving the opposing ram carriers toward each other to press the wire link between the electrode rams such that each ram retracts against the spring bias to cushion the electrode as it contacts the wire link and thereafter maintain a predetermined pressing force against the wire link, the electrode rams providing the sole clamping force on the wire link through the joint to be welded; sensing means associated with each of the electrode rams for sensing the time at which the first of the electrode rams presses against the wire link with a predetermined pressure; and an electrical current source for applying a welding current between the electrode rams in response to the sensing means such that welding current is applied as a predetermined clamping force is applied to the wire link by an electrode ram.

Claim 7

In a link forming apparatus of the type having means for feeding a U-shaped wire segment to a forming station and for retaining the wire segment against lateral movement in the forming station and an anvil movable against the open end of the U-shaped wire at the forming station to close the wire into a wire link, the improvement comprising: opposing ram carriers; opposing electrode rams, one electrode ram mounted to each carrier and spring biased relative to the carrier toward the other electrode ram; drive means for simultaneously driving the opposing ram carriers toward each other to press the wire link between the electrode rams such that each ram retracts against the spring bias to cushion the electrode as it contacts the wire link and thereafter maintain a predetermined pressing force against the wire link, the electrode rams providing the sole clamping force on the wire link through the joint to be welded; sensing means associated with each of the electrode rams for sensing the time at which the first of the electrode rams presses against the wire link with a predetermined pressure; and an electrical current source for applying a welding current between the electrode rams in response to the sensing means such that welding current is applied as a predetermined clamping force is applied to the wire link by an electrode ram.

Claim 8

In a link forming apparatus of the type having means for feeding a U-shaped wire segment to a forming station and for retaining the wire segment against lateral movement in the forming station and an anvil moveable against the open end of the U-shaped wire at the forming station to close the wire into a wire link, the improvement comprising: opposing ram carriers; opposing electrode rams, one electrode ram mounted to each carrier and spring biased relative to the carrier toward the other electrode ram; a pneumatically drive belt for simultaneously driving the opposing ram carriers toward each other to press the wire link between the electrode rams such that each ram retracts against the spring bias to cushion the electrode as it contacts the wire link and thereafter maintain predetermined pressing force against the wire, the electrode rams providing the sole clamping force on the wire link through the joint to be welded; a limit switch associated with each electrode carrier for sensing the first contact of an electrode ram against the wire link with a predetermined pressure; and an electrical current source for applying a welding current between the electrode rams in response to the sensing means such that welding current is applied as a predetermined clamping force is applied to the wire link by an electrode ram.

Claim 9

In a link forming apparatus of the type having means for feeding a U-shaped wire segment to a forming station and for retaining the wire segment against lateral movement in the forming station and an anvil moveable against the open end of the U-shaped wire at the forming station to close the wire into a wire link, the improvement comprising: opposing ram carriers; opposing electrode rams, one electrode ram mounted to each carrier and spring biased relative to the carrier toward the other electrode ram; a pneumatically drive belt for simultaneously driving the opposing ram carriers toward each other to press the wire link between the electrode rams such that each ram retracts against the spring bias to cushion the electrode as it contacts the wire link and thereafter maintain predetermined pressing force against the wire, the electrode rams providing the sole clamping force on the wire link through the joint to be welded; a limit switch associated with each electrode carrier for sensing the first contact of an electrode ram against the wire link with a predetermined pressure; and an electrical current source for applying a welding current between the electrode rams in response to the sensing means such that welding current is applied as a predetermined clamping force is applied to the wire link by an electrode ram.