Fire escape – ladder – or scaffold – Ladder with pivoted prop
Reexamination Certificate
2000-06-05
2002-09-17
Stodola, Daniel P. (Department: 3634)
Fire escape, ladder, or scaffold
Ladder with pivoted prop
C182S156000, CD25S064000, CD25S065000
Reexamination Certificate
active
06450290
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to climbing devices and, more particularly, to a lightweight, folding ladder that provides steps adapted to fold together and lie flat within the frame when the legs of the frame are collapsed into a fold-away position, and whose steps each have a recess that allows a person climbing the ladder to laterally draw closer to an object or supporting wall, when the ladder is in a legs-expanded, open-frame, operative position.
BACKGROUND OF THE INVENTION
In the art of folding ladders with folding steps, it is often observed that the steps of the ladder do not completely fold flat within the frame, when the ladder is folded into an inoperative position. This results in a ladder that is unnecessarily more bulky, when folded.
Another problem that is often encountered with folding ladders is their inability to provide close lateral access to a supporting wall or an object that the user is trying to reach. Although the climber is able to gain height when ascending the steps of the ladder, he is often thwarted from easily approaching an object in the lateral direction. This is so because the edge of each step of the ladder projects beyond the legs of the frame, and abuts the knees and shins of the user as he climbs. The abutting nature of the steps prevents the climber from reaching inwardly towards either a supporting wall or an object that he is trying to reach. In other words, the user cannot step inwardly toward the supporting wall, because his legs are blocked by the steps.
Another problem associated with folding ladders is the thickness of the frame construction. The legs are fabricated unnecessarily thick in order to provide a means by which the internal steps will have sufficient width for the sole of the foot of a climber. Although the user appreciates a well constructed ladder having thick legs and sufficient step width, the added bulk makes the ladder heavier and less maneuverable.
It has been found useful to provide ladders with steps having a large surface area, so that more stability can be provided for the user. This is particularly true when individuals age, and they become less steady as they climb. A folding ladder comprising folding steps having a large surface area is illustrated in U.S. Pat. No. 5,967,260, issued to the present inventor, George E. Spak, on Oct. 19, 1999. The ladder of this invention has large sized steps that can be pushed inwardly beyond the side rails of the frame, so that the climbing individual can lean closer to an object or the supporting wall.
The present invention seeks to include all of the advantages of the aforementioned ladder, yet provide some improvements thereto.
The current invention provides a lightweight folding ladder, whose aluminum, tubular side rails are extremely thin to reduce both weight and bulk. The thin, tubular side rails also allow the climber of the ladder to grip the side rails easily within clenched fists. This provides more stability to the climber as he ascends and descends the ladder. The ladder includes a first, tubular side rail member that is “U”-shaped at the top. Below the top, in a mid-portion of the rails of the first side rail member, a second tubular side rail member is pivotally attached to the first side rails, thus allowing the first and second tubular side rail members to fold upon each other. The ladder also comprises a series of large sized steps that are each pivotally secured to an elongated bar. The steps are upwardly and downwardly foldable within the side rail members in unison, by reason of the elongated bar. Each of the steps also comprises a front edge recess that allows a climber to lean inwardly past the first side rails. The recesses provide a means by which the climber can move laterally closer to a supporting wall or an object. A pair of folding side bars is pivotally attached between the side rails of the first and second side rail members, in order to provide greater stability to the expanded frame. A series of rear support bars extends between the side rails of the second side rail member. The top rear support bar provides a stop for the forward edge of the top step, when the steps are in a fold-down, operative position.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a lightweight folding ladder, whose aluminum, tubular side rails are extremely thin to reduce both weight and bulk. The thin, tubular side rails also allow the climber of the ladder to grip the side rails easily within clenched fists. This provides more stability to the climber as he ascends and descends the ladder.
The ladder includes a first, tubular side rail member that is “U”-shaped at the top. Below the top, in a mid-portion portion of the rails of the first side rail member, a second tubular side rail member is pivotally attached to the first side rails, thus allowing the first and second tubular side rail members to fold upon each other. The ladder also comprises a series of large sized steps that are each pivotally secured to an elongated bar. The steps are upwardly and downwardly foldable within the side rail members in unison, by reason of the elongated bar. Each of the steps also comprises a front edge recess that allows a climber to lean inwardly past the first side rails. The recesses provide a means by which the climber can move laterally closer to a supporting wall or an object. A pair of folding side bars is pivotally attached between the side rails of the first and second side rail members, in order to provide greater stability to the expanded frame, in an operative position. A series of rear support bars extends between the side rails of the second side rail member. The top rear support bar provides a stop for the forward edge of the top step, when the steps are in a fold-down, operative position.
It is an object of this invention to provide an improved folding ladder having large sized folding steps.
It is another object of the invention to provide a folding ladder having large sized folding steps and that is both lightweight and compact.
It is still another object of this invention to provide a folding ladder having large sized folding steps that fold in unison both downwardly and upwardly to their respective operative and inoperative positions.
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patent: 6012548 (2000-01-01), Kim
patent: 65492 (1982-04-01), None
Salzman & Levy
Stodola Daniel P.
Thompson Hugh B.
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