Welding system and method
First Claim
1. A resistance spot welding system comprising:
- a fast follow-up electrode of one RWMA class mounted to one end of a pivot arm for squeezing a primary workpiece and a secondary workpiece together and for following the surface of the secondary workpiece as the weld is formed;
a stationary electrode of another RWMA class positioned opposite the fast follow-up electrode;
a sensor coupled to the stationary electrode for directly measuring the contact force between the fast follow-up electrode and the stationary electrode;
wherein the electrodes are configured for energizing the workpieces with a direct current.
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Accused Products
Abstract
A method of resistance spot welding is disclosed. The method includes providing a first metallic workpiece having a primary surface and a second metallic workpiece having a secondary surface. The method also includes positioning the primary surface into physical contact with a first electrode and a second electrode into physical contact with the secondary surface. The second electrode includes a secondary actuator. The method also includes measuring contact force between the first electrode and the second electrode, and initiating a current through the first electrode when the contact force reaches a preselected force value. The method also includes forming a weld nugget in at least the second workpiece and a depression in the primary surface of the first workpiece, and controlling the location of the weld nugget by using two different classes of electrodes. The depression in the primary surface is substantially undetectable by a visual examination. A resistance spot welding system is also disclosed. The system includes a fast follow-up electrode of one RWMA class mounted to one end of a pivot arm for squeezing a primary workpiece and a secondary workpiece together and for following the surface of the secondary workpiece as the weld is formed. A stationary electrode of another RWMA class is positioned opposite the fast follow-up electrode. A sensor is coupled to the stationary electrode for directly measuring the contact force between the fast follow-up electrode and the stationary electrode. A measuring instrument for measuring a depression formed in the primary surface.
93 Citations
46 Claims
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1. A resistance spot welding system comprising:
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a fast follow-up electrode of one RWMA class mounted to one end of a pivot arm for squeezing a primary workpiece and a secondary workpiece together and for following the surface of the secondary workpiece as the weld is formed;
a stationary electrode of another RWMA class positioned opposite the fast follow-up electrode;
a sensor coupled to the stationary electrode for directly measuring the contact force between the fast follow-up electrode and the stationary electrode;
wherein the electrodes are configured for energizing the workpieces with a direct current. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of resistance spot welding, comprising:
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providing a first workpiece having a use surface in an abutting relationship to a second workpiece having a concealed surface;
positioning a first electrode of a first class in physical contact with the use surface;
maintaining the first electrode in contact with the use surface;
maintaining a second electrode of a second class in contact with the concealed surface;
measuring a signal representative of at least one of a contact force between the electrodes and the workpieces or time;
for at least a pre-selected amount of time or a pre-determined contact force value is exceeded;
applying a pre-determined current by the electrodes for at least a pre-selected amount of time or a pre-determined contact force value is exceeded to form a weld nugget between the first workpiece and second workpiece;
so that a lesser portion of the weld nugget is formed in the first workpiece and a greater portion of the weld nugget is formed in the second workpiece;
wherein a depression formed on the use surface has a lesser depth than a depression formed on the concealed surface. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. An article of furniture providing a concealed surface having a greater depression and a use surface having a lesser depression that is not substantially visible to the unaided eye and produced by a processes of resistance spot welding, comprising:
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measuring a signal representative of a contact force of at least two electrodes of different classes against the use surface or the concealed surface;
applying a pre-selected amount of current by the electrodes after a pre-determined contact force is exceeded;
forming a lesser portion of a weld nugget in the first workpiece and a greater portion of the nugget in the second workpiece;
wherein the greater depression in the concealed surface has a depth greater than the depth of the lesser depression in the use surface. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
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33. A method of resistance spot welding, comprising:
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providing a first workpiece having a use surface in an abutting relationship to a second workpiece having a concealed surface;
positioning a first electrode of a first class in physical contact with the use surface;
maintaining the first electrode in contact with the use surface;
maintaining a second electrode of a second class in contact with the concealed surface;
measuring a signal representative of at least one of a contact force between the electrodes and the workpieces or time;
applying a pre-determined current by the electrodes for at least a pre-selected amount of time or a pre-determined contact force value is exceeded to form a weld nugget between the first workpiece and second workpiece;
controlling the growth of the weld nugget by using a first material composition for the first electrode and a second material composition for the second electrode at least two different classes of electrode material;
so that a lesser portion of the weld nugget is formed in the first workpiece and a greater portion of the weld nugget is formed in the second workpiece; and
wherein a depression formed on the use surface has a lesser depth than a depression formed on the concealed surface. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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Specification