Patent ID: 6303893
Filing Date: 2001-10-16
Classification: B23K

Abstract:
A resistance projection welder for welding first and second work pieces to each other, the first work piece having a body with opposing sides with at least one projection extending from one of the opposing sides and contacting the second work piece to space the body from the second work piece and define an air gap therebetween at a first interface between the first and second work pieces when the first and second work pieces are properly oriented, the resistance projection welder comprising:first and second electrodes spaced relative to each other for receiving the first and second work pieces therebetween, the electrodes being moveable relative to each other from the spaced position to an electrically coupled position where the first electrode is adjacent the first work piece to define a second interface between the first electrode and the first work piece and the second electrode is adjacent the second work piece, and the electrodes being adapted for applying an electrical current to the first and second work pieces;a source of pressurized air for directing a stream of pressurized air toward one of the first and second interfaces; andan air flow sensor for detecting the flow rate of the air stream directed toward one of the first and second interfaces and detecting if the work pieces are properly oriented based on the detected air flow rate.