Apparatus for annealing welded parts and method therefor

An apparatus for annealing welded parts, comprising:

• an annealing furnace which is substantially closed,
• a doorway through which welded parts are placed into and out of said annealing furnace;
• a carriage carrying welded parts on a predetermined course in said annealing furnace;
• a plurality of infrared lamps for heating welded parts carried in said annealing furnace;
• and
• a circulator circulating hot air in said annealing furnace;
• wherein said carriage comprises:
• a plurality of horizontal carriages arranged vertically, each of said plurality of horizontal carriages carrying welded parts horizontally;
• and
• a plurality of vertical carriages carrying welded parts between said plurality of horizontal carriages.

An annealing method for annealing welded parts, said annealing method comprising the steps of:

• carrying welded parts from an inlet to an outlet in a substantially closed annealing furnace having upper and lower portions;
• heating said welded parts by infrared rays during at least part of said carrying step, such that said welded parts are kept at a predetermined temperature for a time not shorter than a predetermined time, while hot air in said closed annealing furnace is circulated;
• placing said welded parts on a first tray at a position corresponding to a doorway of the annealing furnace and a first horizontal carriage;
• moving a first vertical carriage and a second vertical carriage synchronously to a position corresponding to a second horizontal carriage;
• pushing out said first tray from said first vertical carriage to said second horizontal carriage while pushing out a second tray from said second horizontal carriage to a second vertical carriage;
• moving said first vertical carriage and said second vertical carriage synchronously to a third horizontal carriage;
• pushing out said second tray from said second vertical carriage to said third horizontal carriage while pushing out a third tray from said third horizontal carriage to said first vertical carriage;
• moving said first vertical carriage synchronously with said second vertical carriage, to a position corresponding to said first horizontal carriage and said doorway;
• and
• removing said third tray through said doorway.

An annealing method for annealing welded parts, said annealing method comprising the steps of:

• carrying welded parts from an inlet to an outlet in a substantially closed space, said carrying step comprising,
• placing said welded parts on a first tray at a position corresponding to a doorway of an annealing furnace,
• moving a first vertical carriage and a second vertical carriage synchronously to a position corresponding to a first horizontal carriage,
• pushing out said first tray from said first vertical carriage to said first horizontal carriage while pushing out a second tray from said first horizontal carriage to a second vertical carriage,
• moving said first vertical carriage and said second vertical carriage synchronously to a second horizontal carriage,
• pushing out said second tray from said second vertical carriage to said second horizontal carriage while pushing out a third tray from said second horizontal carriage to said first vertical carriage,
• moving said first vertical carriage synchronously with said second vertical carriage, to said position corresponding to said doorway, and
• removing said welded parts placed on said third tray through said doorway;
• and
• heating said welded parts by infrared rays during at least part of said carrying step, such that said welded parts are kept at a predetermined temperature for a time not shorter than a predetermined time, while hot air in said closed space is circulated.