Method and apparatus for forming pipe reinforcing cages and like closed loop objects

A machine for forming reinforcing cages for concrete pipe from lengths of wire fabric comprising:

• support means including elongated guide means extending therealong;
• a pair of carriage means movably mounted on said support means for movement along said guide mean;
• a pair of gripping assemblies, each including gripping jaws rotatably mounted therein;
• means for coupling each one of said gripping assemblies to one of said carriage means;
• means for rotating said gripping jaws within said gripping assemblies;
• infeed means for advancing a section of wire fabric to said gripping assemblies;
• means for actuating said gripping jaws to grip opposite ends of said fabric section;
• and
• carriage drive means coupled to said carriages for advancing said carriages towards one another while said gripping jaws are rotated by said rotating means for forming a cylindrical cage as said gripping assemblies meet one another.

Apparatus for advancing a work piece comprising:

• a support structure including guide means extending therealong;
• carriage means guidably supported by said guide means and including drive means for moving said carriage along said guide means;
• and
• clamping means including first and second elements for selectively clamping a work piece therebetween, said clamping means coupled to said carriage assembly for movement therewith and wherein said first and second elements include movable means engaging a work piece held therebetween for moving said work piece with respect to said clamping means.

Welding apparatus for welding free ends of circumferential wires defining a cylindrical wire cage to provide a line upset welded junction between said wires comprising:

• means for holding opposite ends of a section of wire fabric with circumferentially extending wires having free ends positioned in overlapping abutment with each other;
• a carriage assembly movable along the length of said cylinder and means coupling at least one welding head to said carriage for movement toward and away from said cylinder, said welding head including at least one pair of gripping electrodes movably and insulatively mounted with respect to each other, said head including means coupled to said electrodes for opening and closing said electrodes;
• power suppply means coupled to said electrodes;
• and
• positioning means for sequentially positioning said welding head in aligned relationship to a circumferential wire, lowering said gripping electrodes into proximity with said free ends of said circumferential wire, closing means for closing said electrodes to grip said free ends and means for applying welding energy to said electrodes for providing a line upset weld between the ends of said circumferential wire.

For use in manufacturing pipe reinforcing cages of cylindrical construction whereby free ends of circumferentially extending wires are welded to provide a cylindrical cage, apparatus for straightening the free ends prior to welding comprising:

• combing means having a plurality of teeth defining circumferential wire receiving notches therebetween;
• support means for the wire fabric for positioning said fabric with said free ends engaged within said notches of said combing means;
• and
• means for providing relative motion between said combing means and said wire fabric such that said combing means straightens said circumferential wire ends.

Apparatus for advancing an article such as an elongated work piece comprising:

• a base including guide means extending therealong;
• carriage means for holding an article, said carriage means guidably supported by said guide means and including drive means for moving said carriage along said guide means;
• and
• article support means coupled to said carriage and extensible and retractable as said carriage moves for providing continuous support for an elongated work piece transported by said apparatus as said carriage travels along said guide means.