TELESCOPICALLY EXTENDABLE AND COLLAPSIBLE LADDER WITH AIR DAMPERS

摘要

A telescopically extendable and collapsible ladder assembly has a bottom ladder section, a top ladder section, and one or more intermediate ladder sections. The ladder is, for one or more, e.g. for all, collapsible ladder sections, provided with a pair of air dampers, which air dampers provide retardation of gravity induced velocity of the collapsible ladder section upon collapse thereof. Each of the air dampers comprises an axially compressible and expandable air chamber member having an internal air chamber, said air chamber member being provided with means providing an air flow restricting passage for air pressurized in said internal air chamber and being forced out of said internal chamber upon mechanical compression of the air chamber member from an expanded state into a compressed state as the collapsing ladder section reaches its collapsed position, which air chamber member is adapted to expand upon later extension of said collapsing ladder section.