bent cross section and a tapering length so that one of its ends is wider than the other the narrower end is to be inserted through the hole 31 of the first rung 3 and to stop after it passes the hole 31 of the second rung 3 the wider end is of such width that it stops before passing the hole 31 of the first rung 3 the combining of said strip 4 with the holes 31 is effected by means of its bent sides after strip 4 is set in place the male hinge 11 or the female hinge 12 is inserted into the hollow space of the upright 2 a pressing process is used to press in the same words 114 or 125 as on the male or female hinge onto upright 2 the process keeps the hinge 11 or 12 from separating from the upright 2 after the hinge is pressed in place with upright 2 the end of the arms 113 124 of the male or the female hinges 11 12 as shown in fig1 and 14 prevents strip 4 from coming out of the rung holes 31 because of this arrangement strip 4 cannot come out of the holes 31 of rungs 3 for any configuration of the ladder thus securing rungs 3 in place with upright 2 after the male hinge 11 and the female hinge 12 are engaged with each other a bolt 5 is inserted in the round hole 122 to hold both hinges 11 and 12 in place the bolt 5 has a pin hole for a pin 51 to insert through a lever handle 52 which rotates using pin 51 as a pivot when the.