US 6,318,498 B1Granted

Collapsible ladder

OwnerEd Warnerinventor

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Abstract

A collapsible ladder provides a plurality of segments, each segment associated with one rung of the ladder. The segments may be folded into a flat or planar configuration, after which each segment may be folded against adjacent segments, thereby forming a stacked storage configuration. Each segment provides a generally horizontally oriented rung carried at either end by a generally vertically oriented inside element. A middle element is hinged to each inside element, and an outside element is hinged to each middle element. Side rails may be formed by folding the middle element at 90 degrees to the inside element, and the outside element at 90 degrees to the middle element. A side rail formed in this manner is generally U-shaped when viewed from the end. Springs bias the inside, middle and outside elements into a 90 degree relationship with each adjacent element. A pair of stop pieces, carried by the middle element, maintains the angles between the inside and middle, and between the middle and outside elements, at 90 degrees.

Claims2

Dependent claims

A collapsible ladder, comprising:

(A) at least two segments, each segment comprising:
(a) a rung, having a first and a second end;
(b) first and second inside elements having first and second fastening supports supporting the first and second ends of the rung, wherein the distance between each fastening support and a top edge of each inside element is not equal to a second distance between each fastening support and a bottom edge of each inside element;
(c) first and second middle elements, pivotally carried by the first and second inside elements, respectively, and movable between a first orientation wherein the middle element is in the same plane as the adjacent inside element to a second orientation wherein the middle element is perpendicular to the inside element;
and
(d) first and second outside elements, pivotally carried by the first and second middle elements, respectively, and movable between a first orientation wherein the outside element is in the same plane as the adjacent middle element, to a second orientation wherein the outside element is perpendicular to the middle element;
(B) first spring means, carried between an inside element on a first side of the rung and an outside element on a second side of the rung, for biasing the inside element at 90 degrees to the middle element and for biasing the middle element at 90 degrees to the outside element;
and
(C) second spring means, carried between an inside element on the second side of the rung and an outside element on the first side of the rung, for biasing the inside element at 90 degrees to the middle element and for biasing the middle element at 90 degrees to the outside element.

6 more elements

A collapsible ladder, comprising:

(A) at least two segments, the segments movable between a storage position and an in-use position, each segment comprising:
(a) a rung, having a first and a second end;
(b) first and second inside elements having first and second fastening supports extending from the first and second inside segments, wherein the first and second fastening supports support the first and second ends of the rung, and wherein the first and second fastening supports are not equally distant between a top edge of each inside element and a bottom edge of each inside element;
(c) first and second middle elements, pivotally carried by the first and second inside elements, respectively, and movable between a first orientation wherein the middle element is in the same plane as the adjacent inside element to a second orientation wherein the middle element is perpendicular to the inside element, the first and second middle elements each defining two stop pieces and two stop recesses, whereby the stop piece carried by a first segment is carried within the stop recess of a second segment adjacent to the first segment when the segments are in the storage position;
(d) first and second outside elements, pivotally carried by the first and second middle elements, respectively, and movable between a first orientation wherein the outside element is in the same plane as the adjacent middle element, to a second orientation wherein the outside element is perpendicular to the middle element;
and
(e) wherein the rung is made of extruded aluminum, and the first and second inside elements, middle elements and outside elements are made of cast aluminum, and wherein the rung is thicker than the first and second inside elements, middle elements and outside elements;
(B) first spring means, carried between an inside element on a first side of the rung and an outside element on a second side of the rung, for biasing the inside element at 90 degrees to the middle element and for biasing the middle element at 90 degrees to the outside element;
and
(C) second spring means, carried between an inside element on the second side of the rung and an outside element on the first side of the rung, for biasing the inside element at 90 degrees to the middle element and for biasing the middle element at 90 degrees to the outside element.

7 more elements

Dependencies are inferred from the claim text.