Preparing sheet metal and fabricating roofing shingles

Preparation of sheet metal and fabrication of roofing shingle structures, comprising the steps of:

• (A) processing flat-rolled sheet metal to preselected thickness gage, mechanical properties and surface characteristics;
• (B) cutting the flat-rolled sheet metal into generally-rectangular-configuration unitary blanks, each for fabricating into a unitary roofing shingle structure,
• such a unitary structure having:
• a horizontally-directed axis extending in a direction which is substantially coincident with assembling shingle structures in side-by-side interfitting relationship in a substantially-horizontal direction to provide roof covering, and
• a vertically-directed axis in substantially right-angled relationship to such horizontally-directed axis and extending in a direction in which shingle structures are assembled in overlapping relationship to provide a roof covering;
• (C) designating portions of the unitary blank to be cut away from and portions to be folded over in relation to remaining portions of the unitary blank for fabrication of a shingle structure having an exterior and an interior surface, such exterior surface presenting:
• an upper cover portion which, during roofing assembly of shingle structures in overlapping relationship in such vertical direction, is covered by next vertically-adjacent course shingle structure means in an upward direction, and
• a lower course portion which remains exposed during roofing assembly of shingle structures in such vertical direction overlapping relationship and in such horizontal direction interfitting side-by-side relationship;
• (D) cutting away portions of such unitary blank to assist in providing for folding over sheet metal layers of the shingle structure being fabricated;
• (E) folding over a vertically-extending sheet metal layer on each lateral side of the shingle structure along at least such lower course portion, with
• one such lateral edge layer being folded over onto the exterior surface of the shingle structure being fabricated, and
• the remaining lateral edge layer being folded over onto the interior surface of such shingle structure, with
• each such lateral edge sheet metal layer being folded over along such lower course portion so as to enable receiving a folded over lateral edge sheet metal layer located on an opposite surface of a contiguous shingle structure to provide a weatherproofing interlock along each lateral side of an exposed course portion as part of side-by-side assembly of shingle structures in such generally horizontal direction for roof covering;
• (F) folding over sheet metal layers extending in such horizontal direction, including:
• folding over a lower edge sheet metal layer so as to form a horizontally-extending upwardly-opening slot for receiving a portion of a vertically-adjacent shingle structure, and
• folding over multiple sheet metal layers along a centrally-located horizontally-extending portion of the shingle structure to extend between its lateral sides and be positioned contiguous to a location separating the upper cover portion from the lower exposed course portion of the shingle structure, with
• such centrally-located horizontally-extending folded-over multiple sheet metal layers defining horizontally-extending centrally-located slot means for distal end intercoupling with folded-over multiple sheet metal layers defining a horizontally-extending centrally-located slot means of an adjacent side-by-side shingle structure being assembled in such horizontal direction.