Fire escape – ladder – or scaffold – Safety device for ground-supported ladder
Reexamination Certificate
2001-05-31
2002-07-02
Stodola, Daniel P. (Department: 3634)
Fire escape, ladder, or scaffold
Safety device for ground-supported ladder
C182S206000
Reexamination Certificate
active
06412600
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of ladders. More specifically the present invention relates to a ladder having side rails with engaging notches for receiving an edge of a roof as the ladder leans against the side of a building, thereby stabilizing the ladder against pivoting and falling laterally. The ladder has a ladder upper end and a ladder lower end and is formed of two substantially parallel side rails interconnected by a series of substantially perpendicular and spaced apart foot rungs, wherein the side rails have engaging notches directly opposite each other which are sized and shaped to receive an edge of a building roof.
The ladder is preferably an extension ladder, having a ladder lower segment and a ladder upper segment slidably mounted to the ladder lower segment, and the engaging notches are preferably provided in the ladder upper segment. It is preferred that a series of sets of mutually opposing engaging notches be provided in the side rails so that the most suitably located set of engaging notches can be selected for the particular height of the roof while the ladder leans against the building at an optimum stabilizing angle relative to the ground.
2. Description of the Prior Art
There have long been ladders, and particularly extension ladders, which have been leaned against the sides of buildings to permit the user to climb onto the roof. A problem with these ladders has been that the small amount of friction between the ladder side rails and the roof edge is often insufficient and to obstruct sideways sliding of the ladder upper end along the roof edge. As a result, these ladders sometimes pivot laterally from the ground and fall sideways as the user approaches the ladder upper end, so that the user is injured.
Various ladders and ladder bracing structures have been developed over the years. Problems with these structures have included complexity, high cost, bulkiness and ineffective stabilization while others have positioned the entire ladder on the roof so that ground access is not provided.
Morawski, U.S. Pat. No. 4,179,011, issued on Dec. 18, 1979, discloses a roofing ladder and ladder braces. A brace leg is pivotally suspended from the upper end of each ladder side rail and an abutment plate interconnects the brace legs. Bracing struts secure the brace legs at an outwardly pivoted, deployed position. The ladder side rails are placed against the roof surface one side of a peaked roof so that the brace legs extend over the peak and the abutment plate rests against the roof surface on the other side of the peak, securing the ladder against sliding off the roof. A generally similar roof peak engaging ladder attachment is taught in Lurry, U.S. Pat. No. 4,311,207, issued on Jan. 19, 1982.
Polizzi, U.S. Pat. No. 4,280,590, issued on Jul. 28, 1981, teaches a stabilizing attachment for ladders. Arms protrude perpendicularly from the ladder side rail upper ends for extending over the side edge of a peaked roof and abutting and gripping the roof surface, while the ladder lower end rests on the ground. Other ladder attachments including bracing arms which extend over and abut or grip the roof are those of Stakes, U.S. Pat. No. 4,458,783, issued on Jul. 10, 1984, for a triangular plate and cross-strut roof ladder attachment; Stakes, U.S. Pat. No. 4,787,478, issued on Nov. 29, 1988, for a converging linkage roof ladder attachment; Foradori, U.S. Pat. No. 4,836,331, issued on Jun. 6, 1989, for a ladder safety device-antislip, including rod arms which are slidably extendable from brackets at the ladder upper end; Flores, U.S. Pat. No. 6,019,191, issued on Feb. 1, 2000, for a ladder support system having two bracing arms which are pivotally attached to an axle bar secured across the ladder side rail upper ends to swing over and abut the roof top; Brown, U.S. Pat. No. 4,306,632, issued on Dec. 22, 1981, for a ladder support including a cluster of four bracing arm members diverging from the center of a cross-strut secured across the side rail upper ends; Dwinnell, U.S. Pat. No. 4,949,810, issued on Aug. 21, 1990, for an attachment to stabilize and expand the use of hollow rung ladders, having substantially triangular hoop members extending convergingly from corresponding side rail upper ends to function as bracing arms; Vossler, U.S. Pat. No. 5,775,465, issued on Jul. 7, 1998, for a ladder support including a square U-shaped brace defining a pair of outwardly extending bracing arms interconnected at their proximal ends by the base of the U-shape, the brace being pivotally secured with a pair of hinges to a square ladder encircling hoop releasibly fitting around the ladder upper end, the bracing arms each having a series of fastener holes for passing anchoring screws into the roof upper surface; Hildalgo, U.S. Pat. No. 5,180,032, issued on Jan. 19, 1993, for a ladder stabilizer apparatus usable on a extension ladder, the apparatus having two bracing legs with gripping blocks at their downwardly directed free ends which have resilient surfaces for engaging a roof upper surface; Stennett, U.S. Pat. No. 5,358,071, issued on Oct. 25, 1994, for a gutter protecting ladder attachment in which the bracing arms space the ladder upper end away from the roof edge a sufficient distance to protect the rain gutter; and Taylor, Jr., U.S. Pat. No. 5,664,643, issued on Sep. 9, 1997 for a multi-purpose ladder adapter with forwardly protruding composite bracing arms and clamp means for securing the apparatus around a ladder rung. Bushway, U.S. Pat. No. 6,082,689, issued on Jul. 4, 2000 for a roof staging bracket, does not appear to be directed to ladders specifically.
It is thus an object of the present invention to provide a roof access ladder which includes rail engaging notches for fitting around and over a side edge of a building roof to stabilize the ladder against pivoting and falling laterally.
It is another object of the present invention to provide such a ladder which has the same flat, narrow profile that an otherwise conventional ladder has for compact storage and transport.
It is still another object of the present invention to provide such a ladder having manufacturing costs which are virtually the same as those for a comparable, conventional ladder.
It is finally an object of the present invention to provide such a ladder which is sturdy and reliable.
SUMMARY OF THE INVENTION
The present invention accomplishes the above-stated objectives, as well as others, as may be determined by a fair reading and interpretation of the entire specification.
A ladder is provided for providing access to a building roof having a roof side edge including first and second side rails which are substantially mutually parallel and laterally spaced apart from each other; and a longitudinal series of foot rungs extending perpendicularly between and interconnecting the first and second side rails; where the side rails have engaging notches directly opposite each other which are sized and shaped to receive a roof side edge.
The engaging notches preferably each have substantially an inverted L-shape, defined by a notch horizontal segment and a notch vertical segment. The ladder preferably is an extension ladder including a ladder lower segment having two lower segment side rails and several lower segment foot rungs and a ladder upper segment having two upper segment side rails and several upper segment foot rungs, the ladder upper segment being slidably and telescopingly mounted to the ladder lower segment, and where the ladder upper segment includes the engaging notches. The side rails preferably include a series of sets of mutually opposing the engaging notches so that a suitably located the set may be selected for a particular roof height. The notch horizontal segments preferably each include a high friction substance for increasing the grip of the engaging notch on the roof side edge. The notch vertical segments also preferably each include a high friction substance for increasing the grip of the engaging notch on the roof side
Kubler Frank L.
Stodola Daniel P.
Thompson Hugh B.
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