Fire escape – ladder – or scaffold – Ladder with pivoted prop – Lateral prop
Utility Patent
1999-07-16
2001-01-02
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Ladder with pivoted prop
Lateral prop
C182S107000, C182S214000
Utility Patent
active
06167989
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to ladder safety device. In particular, the ladder safety device provides lateral skidding and lateral stabilizing support for a ladder. Further, the ladder safety device prevents backward skidding and provides backward stabilizing of a ladder.
There are two typical styles of ladders presently in use, the two-legged extension ladder and the step ladder. The extension ladder generally comprises two or more sections, which are coupled to one another. These sections permit one section to slide vertically relative to the other section. This style of ladder typically has its base, or lower end, resting on a supporting base surface, for example, a ground surface, and its upper end leaning against a stationary object, such as but not limited to a wall or roof eaves.
A step ladder generally has four legs, two front legs being arranged in a front leg frame supporting steps or rungs and two back legs. The back legs are joined to the front legs as a frame that is hinged, usually to a top step, to form an “A” shaped frame. A step ladder having four spaced-apart feet need not be leaned against a wall and is generally free-standing.
Extreme care should be exercised when positioning an extension ladder so that a person mounting the ladder does not create an undesirable and potentially harmful force vector. The vector force would tend to cause the feet of the extension ladder to slide backwardly, for example away from the wall. The upper end of the extension ladder may slide down the wall. This sliding can usually be prevented by properly setting the angle that the extension ladder is tilted. Thus, a major force vector caused by the load is primarily directly downward.
An extension ladder is also subject to lateral tipping, especially when the user is stretching out to a side more than he or she should stretch, for example to perform work. That is, rather than getting off the extension ladder and moving the ladder, users often lean laterally outward from the side of the extension ladder. This leaning can cause unbalancing of the ladder to the point where the extension ladder may tip over sideways. This problem is compounded further when the extension ladder's feet are not resting on a planar, horizontal base surface. Where the base surface is uneven or soft, there is a tendency for an extension ladder to lean or shift to one side, thus making it easier to tip when the climber leans to that one side.
Several devices are known in the art for attempting to stabilize an extension ladder. Some of these devices are attached to sides of the extension ladder, either permanently or as a removable attachment. These attached stabilizing devices extend from sides of the ladder and are generally connected to the extension ladder by mechanical connectors. These connectors are often the weakest points in the extension ladder and the stabilizing device. These attached stabilizing devices make a ladder heavier, difficult to carry, and difficult to store, since they add mass, volume, and weight to the ladder.
Further, several devices are known to attach to the leg bottoms of an extension ladder for anchoring the extension ladder to the ground. These devices stabilize the ladder for movement away from the stationary object, however they do not provide lateral stability to the extension ladder.
Therefore, a stabilizing or safety device for an extension ladder that provides lateral stabilizing support is needed. Further, a ladder safety device that is integrally attached to the extension ladder is needed. Furthermore, a stabilizing or safety device for an extension ladder that provides for lateral stability and support on an uneven base is needed.
SUMMARY OF THE INVENTION
A safety device for a ladder, as embodied by the invention, is applied to a ladder that comprises side rails and a plurality of rungs interconnecting the side rails. The safety device comprises a joint and a plurality of side safety supports that are stored in their stored position in one rung of the plurality of rungs. The side safety supports are extendible from the one rung to a stabilizing extended position in which the side safety stabilizers are in contact with a supporting surface. Thus, the ladder safety device provides lateral stabilizing support for the ladder. Further, the ladder stabilizing device prevents backward skidding and provides backward stabilizing for the ladder.
Further, each side safety stabilizer of the plurality of side safety stabilizers comprises a plurality of sections. The plurality of sections is in telescoping relationship with each other. The plurality of side safety stabilizers further comprises a retainer to retain each side safety stabilizer in connection with the one rung. The retainer comprising a ball and socket assembly, which comprises a ball on one of the one rung and side safety stabilizer and a socket on the other of the one rung and side safety stabilizer. The safety stabilizer may be extended from the one rung until the ball engages the socket to stop the extension of the side safety stabilizer from the one rung. The side safety stabilizer comprises a plurality of telescoping sections.
Locking mechanisms are disposed between adjacent sections of the plurality of sections. In one aspect of the invention, the locking mechanism comprises a bayonet locking mechanism between adjacent sections, the bayonet locking mechanism comprising at least one channel and at least one slot on one of the adjacent sections, and at least one locking lug on the other of the adjacent sections. The at least one channel and the at least one slot are generally disposed orthogonal to each other, and the at least one locking lug enters the at least one slot in a first direction and then enters the at least one slot in a second direction that is generally orthogonal to the first direction to lock the adjacent sections with each other.
In another aspect of the invention, the locking mechanisms between adjacent sections of the plurality of sections comprise screw threads and locking connectors on adjacent sections of the plurality of sections.
In another aspect of the invention, the locking mechanisms between adjacent sections of the plurality of sections comprise spring biased locking detents and cooperating recesses on adjacent sections of the plurality of sections.
In yet another aspect of the invention, the locking mechanisms between adjacent sections of the plurality of sections comprise an expandable outer sleeve on one adjacent section and internal actuating device on the other adjacent section, the internal actuating device biasing the sleeve outwardly into an expanded position in which the sleeve is in close frictional engagement with the one adjacent section to lock the adjacent sections with each other.
Further, another aspect of the invention comprises spring-biased detent locking device for locking sections of the stabilizing, side safety support to each other in their extended position.
Further, a still aspect of the invention comprises spring-biased detent locking device for locking the stabilizing, side safety support in its extended position from the rung.
These and other aspects, advantages and salient features of the invention will become apparent from the following detailed description, which, when taken in conjunction with the annexed drawings, where like parts are designated by like reference characters throughout the drawings, disclose embodiments of the invention.
REFERENCES:
patent: 2149781 (1939-03-01), Leizer
patent: 2327317 (1943-08-01), Randall
patent: 5113973 (1992-05-01), Southern
patent: 5423397 (1995-06-01), Boughner
patent: 1137049 (1982-07-01), None
patent: 669518 (1938-12-01), None
patent: 3514734 (1985-11-01), None
patent: 81404 (1983-06-01), None
patent: 582592 (1924-12-01), None
patent: 2529611 (1984-01-01), None
patent: 2182086 (1987-05-01), None
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