Fire escape – ladder – or scaffold – Unitary foldable – rigid scaffold or ladder – Collapsible ladder
Patent
1992-05-27
1993-05-18
Chin-Shue, Alvin C.
Fire escape, ladder, or scaffold
Unitary foldable, rigid scaffold or ladder
Collapsible ladder
E06C 152
Patent
active
052112608
ABSTRACT:
A collapsible ladder that is relatively rigid and includes friction means for controlling the rate of deployment. The ladder comprises a plurality of tubular rungs and side support members pivotally connected between each end of adjacent rungs, each side support member comprising a pair of pivotally interconnected tubular links each having a length less than half of that of the rungs. The links have ends with flat surfaces defining a contacting region for contacting the flat surface of an adjacent pivotally interconnected link. Included are pivotal connecting means comprising a first pivot pin disposed in apertures provided in each adjacent pair of links which define a side support member, and a second pivot pin disposed in apertures provided in each end of each rung and the aperture of at least one side support member, the apertures and pivot pins being disposed inwards from the ends of the links to define support arms outside of the pin, the support arms having bearing surfaces that bear on the adjacent link for providing rigidity of the pivotally interconnected links, about an axis passing transversely through the pivot pin and parallel with the rungs, when the ladder in a deployed condition; and a tension applying fastener associated with at least some of the pins for drawing the contacting regions of the links against one another with a force sufficient to provide a frictional force upon pivoting of the links for restricting the deployment rate of the ladder.
REFERENCES:
patent: 295477 (1884-03-01), Bessier
patent: 3004624 (1961-10-01), Green
patent: 4067413 (1978-01-01), Olsen
patent: 4231449 (1980-11-01), Laurita
patent: 4260039 (1981-04-01), Arato et al.
patent: 4751982 (1988-06-01), Wolfe
Canadian Industrial Design No. 53,339, M. Rosenstraus & T. Stacenko, Feb. 1984.
Bitner Ronald G.
Chin-Shue Alvin C.
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