Collapsible portable ladder

Claim 1

IN A DEVICE HAVING A PLURALITY OF LADDER SECTIONS HINGEDLY CONNECTED AT THEIR ADJACENT ENDS FOR COMPACT FOLDING OF THE SECTIONS INTO SIDE BY SIDE RELATIONSHIP IN WHICH THE LADDER SECTIONS INCLUDE A PAIR OF SPACED RAILS INTERCONNECTED BY A PLURALITY OF TRANSVERSELY DISPOSED RUNGS, MEANS FOR DETACHABLY LOCKING THE SECTIONS IN RIGID ALIGNMENT WITH ONE ANOTHER COMPRISING AN ELONGATE CHANNEL MEMBER TELESCOPICALLY MOUNTED ON THE RAIL OF ONE OF SAID SECTIONS AND ADAPTED FOR FREE LONGITUDINAL MOVEMENT THEREON BACK AND FORTH PAST SAID RUNGS, SAID MEMBER FREELY SLIDING DOWNWARDLY INTO OVERLAPPING SIMULTANEOUS ENGAGEMENT WITH ADJOINING RAILS WHEN THEY ARE IN GENERALLY VERTICAL ALIGNMENT WITH ONE ANOTHER THEREBY OVERLAYING THE HINGE CONNECTION BETWEEN SAID RAILS AND PREVENTING HINGED MOVEMENT THEREBETWEEN, OUTWARDLY PROTRUDING FIRST ABUTMENT MEANS PROVIDED BY SAID HINGE CONNECTION, AND INWARDLY EXTENDING SECOND ABUTMENT MEANS CARRIED BY SAID CHANNEL INTERMEDIATE THE ENDS THEREOF COOPERATIVELY ENGAGING SAID FIRST ABUTMENT MEANS WHEN IN OVERLAPPING LOCKING POSITION AND PREVENTING FURTHER DOWNWARD MOVEMENT OF SAID CHANNEL MEMBER, SAID MEMBER WHEN IN LOCKING POSITION BEING CAPABLE OF FREE UPWARD UNLOCKING MOVEMENT TO RELEASE THE HINGE CONNECTION FOR FOLDING OF SAID SECTIONS.