Abstract: An interlocking structural element is disclosed for the construction of cabinets and enclosures, including modular cabinets and enclosures. Four equal lengths of the interlocking structural element can be used in conjunction with simple flat rectangular panels to fabricate a single enclosure. Additional lengths may be used to fabricate an enclosure with multiple compartments. The interlocking structural element may be fabricated by extruding metal or other material such as plastic. The element incorporates slots for easy mounting of shelves, printed circuit boards or other objects within the enclosure.

Abstract: Continuous thermal treatment for the strengthening of metallic workpieces is carried out by placing a batch of at least two workpieces on a basket hinged on a continuously advancing conveyor chain; introducing said workpieces in said basket through a first instantaneously opening and closing gate into a uniformly heated first thermal treating step wherein the continuously advancing workpieces are heated at a temperature of about 560.degree. C.; introducing the heated workpieces in said basket through a second instantaneously opening and closing gate into a second thermal treatment step placed immediately after the end of the first step and in communication therewith, by lifting a vat containing a cooling fluid to immerse said workpieces in said basket into the cooling fluid of said vat to rapidly cooling said workpieces to a temperature of about 100.degree. C. and thereafter lowering said vat.