Shingle structure with reentrant joint configurations and a nailing tab

Claim 1

A SHINGLE STRUCTURE COMPRISING A CONTINUOUS SHEET OF METAL HAVING, IN NORMAL POSITION, AN UPPER EDGE, A LOWER EDGE, A RIGHT-SIDE EDGE, A LEFT-SIDE EDGE, AN UNDERSURFACE NORMALLY FACING A ROOF OR THE LIKE AND AN OUTSIDE SURFACE NORMALLY EXPOSED TO WEATHER, SAID STRUCTURE HAVING MEDIAL GROOVES AND AN END GROOVE ADJACENT SAID RIGHTSIDE EDGE OF SAID SHINGLE STRUCTURE, ALL OF SAID GROOVES BEING DEFINED BY INDENTATIONS IN SAID SHEET RUNNING FROM LOWER EDGE TO SAID UPPER EDGE AND FORMED TO BE DEEPER AT SAID LOWER EDGE AND SHALLOWER AT SAID UPPER EDGE AND TO INTERSECT THE SURFACE DEFINING SAID LOWER EDGE, SAID LOWER EDGE BEING FORMED BY A DEEP BOX-BEND OF SAID SHEET, THE PORTION OF SAID LOWER EDGE BOX-BEND NORMAL TO SAID SHEET BEING WIDER THAN SAID GROOVES AND THE PORTION OF SAID BOX-BEND GENERALLY PARALLEL TO SAID SHEET AND UNDERLYING THE UNDERSURFACE THEREOF, SAID UPPER EDGE BEING FORMED BY A FOLDED-BACK PORTION OVERLYING SAID OUTSIDE SURFACE AND SAID UPPER EDGE FOLDED-BACK PORTION ALSO EXTENDING BEYOND SAID LEFT-SIDE EDGE, SAID LEFT-SIDE EDGE BEING FORMED BY A BENT-BACK PORTION UNDERLYING SAID UNDERSURFACE, AND SAID RIGHT-SIDE EDGE BEING FORMED BY A DOUBLED-BACK PORTION OVERLYING SAID OUTSIDE SURFACE, THE CORNER FORMED BY THE INTERSECTION OF SAID UPPER EDGE AND SAID RIGHT-SIDE EDGE BEING FORMED WITH AN EXTENSION OF SAID DOUBLED-BACK PORTION OF SAID RIGHT-SIDE EDGE FLATTENED TO FORM A DOUBLE THICKNESS NAILING TAB HAVING A BOX-BEND AT THE EDGE THEREOF AND SAID UPPER EDGE FOLDED-BACK PORTION TERMINATING TO FORM A DAM ACROSS THE END OF THE GROOVE DISPOSED ADJACENT THE RIGHT-SIDE EDGE, WITH THE FOLDED-BACK PORTION OF THE UPPER EDGE ALSO BEING OFFSET TO RECEIVE THE FOLDED-BACK PORTION OF A SECOND SHINGLE STRUCTURE WHICH EXTENDS BEYOND THE LEFT-SIDE EDGE OF SAID SECOND SHINGLE STRUCTURE WHEREBY THE SECOND SHINGLE STRUCTURE CAN BE INTERLOCKED WITH THE RIGHT-SIDE EDGE OF THE FIRSTMENTIONED SHINGLE STRUCTURE.