Patent ID: 6371686
Filing Date: 2002-04-16
Classification: A45B,F16B,Y10T

Abstract:
An improved central shaft for a collapsible umbrella wherein the central shaft includes a plurality of telescoping tubes and comprising: an inner tube, a first middle tube, a second middle tube, a third middle tube and an outer tube; the outer tube having a first flat indent plane at a top portion thereof; the third middle tube is slidable in the outer tube and has a second flat indent plane on a first side mating against the first flat indent plane, a first circular perimeter section at one end below the second flat indent plane, and a third flat indent plane at an upper portion on a second, opposite side thereof and a second circular perimeter section below the third flat indent plane; the second middle tube is slidable in the third middle tube and has a fourth flat indent plane at a first side thereof mating against the second flat indent plane, a third circular perimeter section at a lower portion of a second, opposite side thereof, and a first concave section at an upper portion on the second side thereof; the first middle tube is slidable in the second middle tube and has a fifth flat indent plane and a second inside concave section at an upper portion on a first side thereof, a sixth flat indent plane at a lower portion on a second, opposite side thereof, and a third inside concave section at the second side above the sixth flat indent plane; the inner tube is slidable in the first middle tube and has a seventh flat indent plane on a first side thereof; a lower portion mating against the fifth flat indent plane, a fourth inside concave section above the seventh flat indent plane, and a fifth inside concave section on a second, opposite side thereof, whereby the circular perimeter, the flat indent planes and the inside concave section latch and confine adjacent telescoping tubes to prevent the disengagement of the telescoping tubes.