Folding ladder

Claim 1

A COMBINATION FOLDING STEP LADDER AND EXTENSION STRAIGHT LADDER, COMPRISING A PLURALITY OF SECTIONS EACH HAVING SPACED LONGITUDINAL STILES CONNECTED BY TRANSVERSE RUNGS, THE CONTIGUOUS ENDS OF THE STILES OF ADJACENT SECTIONS BEING CURVED TO PERMIT RELATIVE TURNING OF THE SECTIONS, HINGE MEANS LOCATED ALONG THE LONGITUDINAL CENTER LINES OF SAID STILES AND CONTINUOUSLY SECURING ADJACENT SECTIONS TO EACH OTHER FOR RELATIVE TURNING MOVEMENTS IN EITHER DIRECTION FROM A FOLDED CONDITION IN WHICH THE SECTIONS LIE CONTINGUOUSLY IN ADJACENT PLANES TO A FIRST UNFOLDED POSITION IN WHICH THE SECTIONS ARE IN ALIGNMENT TO FORM A STRAIGHT EXTENSION LADDER AND TO A SECOND UNFOLDED POSITION IN WHICH THE SECTIONS ARE AT AN ANGLE TO FORM A STEP LADDER, SAID HINGE MEANS HAVING LATCH MEANS COOPERABLE WITH A STILE OF ONE OF SAID ADJACENT SECTIONS TO SECURE SAID SECTIONS IN SAID SECOND UNFOLDED POSITION, AND LOCK MEANS MOUNTED ON A STILE OF AT LEAST ONE SECTION AND MOVABLE LONGITUDINALLY OF THE STILE TO ENGAGE AN ALIGNED STILE OF AN ADJACENT SECTION FOR SECURING THE SECTIONS IN SAID FIRST UNFOLDED POSITION.