1. A twin wire welding apparatus comprising:
a first contact tube for guiding a first consumable electrode toward a weld puddle and for transferring welding current to the first consumable electrode;
a second contact tube for guiding a second consumable electrode toward said weld puddle and for transferring welding current to the second consumable electrode;
a power source connected to said first and second contact tubes for providing a potential to said two consumable electrodes; and
a feeding arrangement for feeding a cold wire into said weld puddle.
2. A welding apparatus according to claim 1, wherein said feeding arrangement is arranged to feed said cold wire into said weld puddle at an angle of less than 5\xb0 with respect to a surface normal.
3. A welding apparatus according to claim 1, wherein said first and second contact tubes are formed in separate contact tips.
4. A welding apparatus according to claim 1, wherein the first and second contact tubes are connected to single power source via first and second contact devices, wherein said first and second contact devices are separate for the first and second contact tubes.
5. A welding apparatus according to claim 1, wherein said welding apparatus further includes a contact tube spacing mechanism for adjusting a spacing between a respective tip of said first and second contact tubes.
6. A welding apparatus according to claim 1, wherein said welding apparatus further includes a contact tube inclination mechanism for adjusting an inclination between respective length axes of said first and second contact tubes.
7. A welding apparatus according to claim 1, further comprising an electrically insulated duct for electric insulation of said cold wire to be electrically insulated from said first and second contact tubes in an electrode assembly, wherein said electrode housing contains said first and second contact tubes and said electrically insulated duct.
8. A welding apparatus according to claim 7, wherein the insulated wire duct is a ceramic tube.
9. A welding apparatus according to claim 7, wherein the electrically insulated duct comprises an electrically insulated portion in a wire straightening unit for straightening one or more of the consumable electrodes and cold wire.
10. A welding apparatus according to claim 7, wherein an individual wire straightening unit is provided for the cold wire separate from wire straightening units of the first and second consumable electrodes of the electrode assembly.
11. A welding apparatus according to claim 7, wherein the electrically insulated duct comprises an electrically insulated portion in a wire feeder unit for feeding one or more electrodes and cold wires towards a workpiece.
12. A welding apparatus according to claim 7, wherein an individual wire feeder unit is provided for the cold wire separate from wire feeding units of the first and second consumable electrodes.
13. A welding apparatus according to claim 1, wherein an individual speed control unit is provided for the cold wire separate from a speed control unit associated with the first and second consumable electrodes.
14. A welding apparatus according to claim 1, wherein the cold wire in the electrically insulated duct is positioned between the first and the second consumable electrodes with respect to a welding direction on a workpiece.
15. A welding apparatus according to claim 1, wherein the cold wire is arranged upstream of the first and the second consumable electrodes with respect to a welding direction on a workpiece.
16. A welding apparatus according to claim 1, wherein the cold wire is arranged downstream of the first and second consumable electrodes with respect to a welding direction on a workpiece.
17. A welding apparatus according to claim 1, wherein at least one of a feeder unit and a straightening unit for the first and second consumable electrodes provides a feedthrough for guiding the cold wire through the feeder unit.
18. A welding apparatus according to claim 1, wherein said welding apparatus is a gas metal arc welding apparatus including a gas cup for directing a protective gas flow toward a weld area common for said first and second electrodes.
19. A twin wire welding method comprising:
guiding a first consumable electrode through a first contact tube toward a welding area;
guiding a second consumable electrode through a first contact tube toward the welding area; and
transferring a welding current to the first and second consumable electrodes from a power source connected to the first and second consumable electrodes via said first and second contact tubes to maintain a first and a second arc respectively for the generation of a weld puddle.
20. A method for welding according to claim 19, further comprising directing a protective gas flow toward the weld area common for said first and second electrodes wherein a weld puddle is maintained by said a first and a second arc respectively under the protective gas flow.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Capacitive apparatus for sensing occupant weight applied to a seating surface of a seat, comprising:
a deflectable dielectric mat disposed between said seating surface and a frame of said seat;
an elongate flexible circuit folded around said dielectric mat and supporting first and second sets of conductor strips in proximity to upper and lower surfaces of said dielectric mat, respectively, where said first and second sets of conductor strips periodically overlap in a direction perpendicular to the upper and lower surfaces of said dielectric mat to define a distributed array of capacitive load cells responsive to occupant weight applied to said seating surface; and
capacitance measurement circuitry coupled to said conductor strips for measuring a capacitance of a selected capacitive load cell by coupling a measurement circuit to a pair of conductor strips that define the selected capacitive load cell.
2. The apparatus of claim 1, where the capacitance measurement circuitry applies a reference potential to conductor strips that do not define the selected capacitive load cell.
3. The apparatus of claim 1, where said flexible circuit includes a depending connector stub for coupling said capacitance measurement circuitry to said conductor strips.
4. The apparatus of claim 1, where said capacitance measurement circuitry sequentially measures a capacitance of each capacitive load cell.
5. The apparatus of claim 4, where said capacitance measurement circuitry detects a cumulative change in capacitance of the capacitive load cells as a measure of deformation of said dielectric mat due to occupant weight.
6. The apparatus of claim 4, where said capacitance measurement circuitry detects capacitance changes of said capacitive load cells to determine a distribution of the occupant weight across said seating area.