Weld nut welding apparatus

A weld nut welding apparatus comprising:

• an upper electrode equipped with an electromagnet;
• a lower electrode disposed such as to oppose the electromagnet mounting surface of said upper electrode;
• a plate material placed on said lower electrode;
• a weld nut, having a threaded portion attracted by said electromagnet mounted on said upper electrode and placed such as to abut against said plate material, said weld nut having an annular groove formed in the surface thereof which abuts against said plate material;
• a welding power source for supplying a welding current to said plate material and said weld nut which are clamped between said upper and lower electrodes via said electrodes, said welding current being of such a magnitude as to cause said weld nut to be welded to said plate material;
• a punch provided in a cylindrical chamber which is formed inside said lower electrode such as to extend therethrough in such a manner that said punch is vertically movable through a guide, said punch having at its upper end an annular projection which presses said plate material toward said upper electrode and into said annular groove thereby to punch a bore in said plate material in correspondence with said annular groove, and said punch further having in its center a passage bore opened toward said annular projection such as to discharge a waste piece punched out of said plate material;
• and
• a pin opposing said passage bore and downwardly movable in said upper electrode, said pin pushing a waste piece punched out of said plate material into said passage bore by moving through the threaded portion of said weld nut.

A weld nut welding apparatus comprising;

• a press block equipped with an electromagnet;
• an upper electrode movable sidewardly of said press block;
• a lower electrode disposed such as to oppose both the electromagnet mounting surface of said press block and said upper electrode;
• a plate material placed on said lower electrode;
• a weld nut, having a threaded portion attracted by said electromagnet mounted on said press block and placed such as to abut against said plate material, said weld nut having an annular groove formed in the surface thereof which abuts against said plate material, said annular groove having a tapered inner peripheral surface, and said weld nut being contacted at its side surface by said upper electrode;
• a welding power source for supplying a welding current to said plate material and said weld nut which are placed on said lower electrode via said upper and lower electrodes, said welding current being of such a magnitude as to cause said weld nut to be welded to said plate material;
• a punch provided in a cylindrical chamber which is formed inside said lower electrode such as to extend therethrough in such a manner that said punch is vertically movable through a guide, said punch having at its upper end an annular projection which presses said plate material toward said press block and into said annular groove thereby to punch a bore in said plate material in correspondence with said annular groove, and said punch further having a recess surrounded by said annular projection, said recess having a tapered surface which corresponds to the tapered surface of said annular groove;
• and
• a pin opposing said recess and downwardly movable in said press block, said pin pushing a waste piece punched out of said plate material into said recess by moving through the threaded portion of said weld nut.