US 5,676,862 A · Electric resistance welder having capability of consistent seam welding and heat-treating

Abstract

An electric resistance welder welds, hot reduces, tempers and planishes overlapped metal workpieces. The welder incorporates two transformers (50, 60) which are connected to two sets of wheel electrodes (26, 28 and 36, 38). Electric current from a first transformer (50) flows through workpieces (16) and returns through a second transformer (60). The first set of wheel electrodes (26, 28) creates a weld joint and the second set (36, 38), depending on the shape, area, and pressure of the wheels, either reduces the weld thickness, tempers the weld joint, or both. A control circuit (72) includes a current sensor (70) and power factor adjuster (80). The current sensor senses current flow through the first transformer during the welding process. As the current changes, particularly when the sets of wheel electrodes engage and disengage the workpieces, the power factor adjuster (72) adjusts the power factor to maintain constant heat to the workpieces. The electric resistance welder produces continuous, even tempered seam welds having reduced thickness.

Claims20

Dependent claims

An electric resistance welder for welding overlapped workpieces to each other, the electric resistance welder comprising:

a first pair of opposed wheel electrodes;
a biasing system for urging the first pair of wheel electrodes resiliently toward each other such that the first pair of wheel electrodes engage each other in an absence of workpieces and engage opposite sides of overlapped workpieces during a weld operation;
a second pair of wheel electrodes;
a second biasing system for biasing the second wheel electrodes toward each other such that the second wheel electrodes engage opposite sides of overlapped workpieces and in the absence of workpieces engage each other;
a first power supply electrically connected between two wheel electrodes of the first and second pair of wheel electrodes;
a second power supply electrically connected between the other two wheel electrodes of the first and second pair of wheel electrodes, such that a welding current flows between the first pair of wheel electrodes and a heat-treating current flows between the second pair of wheel electrodes;
the first and second pairs of electrodes being disposed in alignment with each other such that as the first and second pairs of electrodes and the workpieces move relative to each other, the first pair of wheel electrodes weld the workpieces together and the second pair of wheel electrodes cause additional heating of the weld.

4 more elements

Dependencies are inferred from the claim text.

Electric resistance welder having capability of consistent seam welding and heat-treating

Life of this patent

Electric resistance welder having capability of consistent seam welding and heat-treating

Life of this patent

Abstract

Claims20