Note: Descriptions are shown in the official language in which they were submitted.
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ESCAPE LADDER HAVING
HIGHLY NESTING RUNGS
Technical Field
This invention is to an escape ladder which allows an occupant of a building
to
escape through a window during an emergency, such as a fire.
Back~zround Art
There has long existed a need for a light-weight, collapsible ladder that may
be
secured to, for example, a window or other aperture of a mufti-story building
in order to
provide occupants of the building a secondary route of escape during a fire.
Many patents
disclose inventions which are intended to fiilfill this long-felt need. For
example, U. S. Patent
No. 190,342 to Lake discloses a collapsible ladder having rungs that are
secured together by
metal rods which are formed into rectangular shapes so as to secure two rungs
together in a
non-collapsed condition of the ladder. Each rung (except the bottom rung) has
two sets of
holes which are spaced forward and backward on the tread of the rung, with one
set of holes
for securing the ladder rung from above and the other set of holes for
securing the next
ladder rung below.
U.S. Patent No. 314,287 to Feigenbaum discloses a rope ladder having round
rungs
which fit between the floor joists of a building, the ladder being deployed
when a trap door is
removed and put out of the way so as to allow the ladder to be let down to the
floor below.
~ U.S. Patent No. 1,424,115 to Nileon discloses a rope ladder having hollow
tubular
rungs, with the ends of the rungs having one-half removed so as to be semi-
circular in cross-
section and bent at a right angle to tightly bind a cable, and at the same
time engage a wall of
a building, whereby the ladder rung will be held away from the side of a
building a distance
sufficient to permit the user to gain a foot hold on the ladder rung.
U.S. Patent No. 4,098,372 to Luckey discloses a collapsible ladder made of a
non-
combustible material having two flexible strings with rungs threaded thereon
at spaced
distances. These rungs have divergent limbs so that, when the ladder is
collapsed, the rungs
may be stacked on one another in such a way as to leave between each pair of
adjacent rungs
a free hollow area for complete reception of segments of a cable or strip
elements which
support the rungs when the ladder is in use.
U.S. Patent No. 4,298,097 to Eriksson discloses an escape ladder assembled of
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rungs, the ends ofwhich are attached between flexible lateral members, with
the rungs being
of metal material and capable ofbeing stacked, and with the upper portion of
the escape
ladder intended to be attached to a wall or the hlce.
U.S. Patent No. 4,846,306 to Ventz discloses a rope escape ladder including a
pair of
parallel support ropes and a series of narrow rungs disposed between the
support ropes,
wherein the rungs are so narrow that no more than one hand or one foot can be
placed on a
rung at a time.
U.S. Patent No. 5,605,205 to Douglas et al discloses a collapsr'bIe ladder
having
hooks for securing to a window surface, a rigid spacing member extending
between the
hooks and defining a slot, an elongated flexible support element ofnyion rope
or steel cable
attached to the hooks, a plurality of rungs, farmed from a molding process,
that stack and
nest with a storage region between each rung for storing the flexible support,
a fastener to
connect each rung to the flexible support, and a cover for holding the rungs
in the nested
state. The cover has a neck portion, and a handle which extends through the
slot in the rigid
spacing member. The handle is movable in the slot to thereby release the cover
and deploy
the ladder to the extended state.
Despite a myriad ofpatents having addressed the need for a light-weight,
collapsible
ladder for over a century of development, there remains the need for a light-
weight escape
ladder which can be easily deployed and safely descended in a fire emergency
in case the
primary means of escape (such as a stairwell) is blocked and wherein, in the
collapsed state,
the rungs of the ladder nest to a high degree of compactness.
Disclosure of the Invention
The present invention provides a very cou~act, collapsible ladder that is
light in
weight, yet can be rapidly deployed and safely descended during a fire
emergency. A first
object of the invention is to insure that the ladder is safe nail easy to
descend. A second
object of the invention is to provide a cover with handle that allows the
ladder to be easy
and reliably deployed by dropping the handle out a window once an attaching
member has
been placed over the s$1 of the window. A third object of the invention is to
minimize the
space required to store the collaps~'ble ladder when not is use.
;0
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AMENDED SHEET
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DE I96 38 704 A1 dislcoses a collapsible ladder comprising several rungs which
are
connected by flexible elements which are guided through bores in the rungs.
AMENDED SHEET
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Brief Description of the Drawings
The present invention will be more fully understood from the below detailed
description and the accompanying drawings. The various embodiments of the
invention are
given by way of illustration only, and thus, are not intended to limit the
scope of the
invention, wherein:
Fig. 1 illustrates a perspective view of the ladder of the present invention
when in the
deployed state;
Figs. 2A and 2B illustrate perspective and cross-sectional views,
respectively, of a
rung of the ladder illustrated in Fig. 1;
Figs. 3A - 3C illustrate cross-sectional views of alternative techniques for
fastening a
narrow fabric support to a modified rung having a single slot, near each rung
end, through
which the narrow fabric support is threaded;
Fig. 4 is a cross~sectional view which illustrates an alternative way to
thread the
narrow fabric support to a rung having three slots on each end;
Figs. SA and SB are cross-sectional views of alternative rung cross-sections,
with
each rung made of an elongate material having an integral stand-offprojection
positioned at
each end of each rung, wherein each rung is, substantially, identically shaped
of linear
segments and sized the same as the other rungs, and all the rungs of the
ladder nest to a high
degree of compactness when the ladder is in the collapsed state;
Figs. 6A and 6B are cross-sectional views of other alternative rung cross-
sections,
with each rung made of an elongate material having an integral stand-off
projection
positioned at each end of each rung, wherein each rung is sized differently
from the other
rungs of the ladder and the rungs nest to a high degree of compactness when
the ladder is in
the collapsed state;
Fig. 7 is a cross-sectional view of the ladder rung of the preferred
embodiment of the
invention, each rung being formed so as to have an arc-shaped portion in a
region including
the top portion of each rung, with a straight flange on at least one side
ofthe ar~shaped
portion, and wherein each rung end includes an integral, stand-off projection,
is sized
substantially identically with the other rungs of the ladder, and the rungs
nest to a high
degree of compactness in the collapsed state of the ladder;
Fig. 8 illustrates a perspective view of the ladder of the present invention
when in the
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non-deployed, collapsed state and bound by a cover that aids in picking up the
ladder (as, for
example, from a storage box) and in dropping the ladder rungs as a group, once
an attaching
member has been hooked over window sill, in order to deploy the ladder in a
tangle-free
manner during a fire or other emergency;
Figs. 9A and 9B illustrate a mounting plate which may be mounted to a wall
surface
beneath a window sill for an attaching member;
Figs. l0A and lOB illustrate two surfaces, respectively, of a cover for
storing and
deploying an escape ladder that is designed for use from a second-floor
window. The cover
is shown when in a flat, laid-out position. These figures show the dimensions
of the cover
and the positioning of temporary fasteners on the cover which enable the cover
to perform
three functions, as will be descn'bed in the next section, below; and,
Figs. 11A and 11B illustrate two surfaces, respectively, of a cover for
storing and
deploying a ladder that is designed for use from a third-floor window. The
cover is
illustrated when in a flat, laid-out position. These figures show the
dimensions of the cover
and the positioning of temporary fasteners on the cover which enable the cover
to perform
the same three fimctions as the cover illustrated in Figs. l0A and l OB.
Best Mode for Carrying Out the Invention
As used herein, "highly nesting" and "high degree of compactness" refer to
rungs that
nest in a stack having 10 or more rungs per 15.24 cm of stack height when in
the collapsed
state.
Referring to Fig. 1, a perspective view of the ladder 1 in its deployed state
is
illustrated. The ladder includes an attaching member 2 having two hooks, each
with an open
end facing the same direction so that the attaching member 2 may be hooked
over a window
sill (not illustrated). The attaching member 2 is of tubular construction
which may be solid
or hollow (not illustrated) and includes a support bar 3 to which may be
attached one or
more narrow fabric supports 4. The narrow fabric supports are made of a
webbing material
such as nylon (or any other known, flame resistant, high strength, light
weight synthetic
material) for supporting the rungs 5 of the ladder 1. The narrow fabric
support should
ideally be capable of supporting a load of about 1,364 kilograms and, in the
preferred
embodiment, is made of nylon that measures about 2.54 cm in width and 3.18 mm
in
thickness.
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The rungs 5 of the ladder are made of a thin, high-strength material such as
metal,
preferably aluminum having a thickness of about 1.6 mm to 2.1 mm. Other
materials having
a tensile strength of about 7 kg/mm2 or higher, such as steel, titanium,
carbon-filament, etc.,
may be substituted for ahuninum. Having the rungs made of a high-strength
material enables
the rungs to be strong even though the thickness of the rung material is less
than 6.4 mm,
and is one of the factors that enables the rungs to be nested to a "high
degree" in the
collapsed state. If the rungs are made of sheet metal, such as steel or
ahuninum, this allows
the rungs to be economically produced by stamping; however, the rungs may also
be
produced in other ways, such as by using extruded ahuninum or molded
materials. An
important feature ofthe rung design is that there is a stand-off projection 6,
positioned at or
near each rung end, which is integral to the rung. The stand-off projections 6
are for the
purpose of making the ladder easy and safe to descend by ensuring that each
rung is
positioned a minimum distance from a wall, thereby allowing room for one's
toes so that the
ball of the foot may be placed squarely on the rung as one descends the
ladder. In the
situation where the rungs are shaped by being extruded, the two stand-
offprojections 6 may
be formed by removing metal from between the rung ends as, for example, by
stamping. In
this way, the weight of each rung may be kept low. A friction-enhancing
material or pattern
(not illustrated) may be applied to, or formed on, the top portion of the rung
which forms the
tread of each ladder step. Preferably, the tread portion of the step is at
least 2.54 cm in
width so as to provide a comfortable support, even for a user without shoes.
Another important feature of the rung design is that the multiple rungs of the
ladder
nest to a high degree of compactness, and with the narrow fabric support
folded toward the
center of each rung, thereby ensuring that the ladder is very compact in the
collapsed state
and deploys properly without tangling when the multiple rungs in the collapsed
state are
dropped as a bundle, as will be descn'bed in more detail with reference to a
later figure.
The preferred embodiment of the present invention, as well as most other
illustrated
embodiments, meet American National Standards Institute Standard No. 14.2 -
1990. In
addition, the narrow fabric support of the present invention meets the
National Fire
Prevention Association 701 - Standard Methods of Fire Tests for Flame
Resistant Textiles
and Films (Small-Scale Test).
Fig. 2A and 2B are perspective and cross-sectional views, respectively, of a
first
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embodiment of a rung of a ladder according to the present invention. According
to this
embodiment, there are two slots 7 near the end 8 of each rung, and the rung-
end cross-
section is arcuate in shape, with the arc radius being 7.6 cm or greater.
These figures also
show how one or more narrow fabric supports 4 may be threaded through the
slots 7 and
fastened with a fastener such as a rivet 9 in order to support the rungs 5 at
fixed vertical
spacings when the ladder is in use.
Figs. 3A - 3C illustrate crossrsectional views of alternative techniques for
fastening
one or more narrow fabric supports 4 to a modified rung having a single slot
7, near each
rung end 8, through which the narrow fabric support 4 is threaded. Referring
to Fig. 3A, a
clip 10 has been inserted through the single slot 7 to spread out the stress
on the narrow
fabric support 4. Rivet 9 fastens the clip 10 in place. In Figs. 3B and 3C, a
compression
fastener 11 is used to grip the narrow fabric support. The narrow fabric
support may itself
be woven with one or more slits 12 which may then be separated by a spacing
member 13,
such as the rod illustrated in Fig. 3B, which fimctions to support the rung 5.
Fig. 4 is a cross-sectional view which illustrates an alternative way to
thread the
narrow fabric support 4 to a rung having three slots ? near each rung end 8.
Figs. SA and SB are cross-sectional views of pairs of rungs that stack and
nest to a
high degree. The rung pairs illustrated in these two figures have different
cross-sections,
with each rung including an integral stand-offprojection 6 near each end. The
cross-section
illustrated in Fig. SA is that of an inverted V, which is less desirable than
the cross-section
illustrated in Fig. SB because there is insufficient support surface at the
inverted V vertex to
comfortably stand on the ladder rung without shoes. The cross-section
illustrated in Fig. SB
is that of an inverted channel, with a top fat surface which is at least 2.5
cm wide. These
figures give examples of alternative rung cross-sections wherein each rung 5
is identically
shaped of linear segments, is identically sized with the other rungs of the
ladder, and all the
rungs of the ladder both stack and nest to a high degree when the ladder is in
the collapsed
state.
Figs. 6A and 6B are additional cross~sectional views of pairs of rungs that
stack and
nest to a high degree. The rung pairs illustrated in these two figures have
still different
cross-sections, with each rung end including an integral stand-off projection
6 and each rung
having a mininnun step surface of at least 2.54 cm in width, Fig. 6A, or a
minimum arc
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radius of 7.62 cm, Fig. 6B. These figures give examples of alternative rung
cross-sections
wherein each rung is sized differently from the other rungs of the ladder, and
wherein all the
rungs of the ladder both stack and nest to a high degree when the ladder is in
the collapsed
state.
Fig. 7 is a cross-sectional view of a pair of rungs of a design that is the
preferred
embodiment of the invention, wherein each rung is formed so as to have an arc-
shaped
portion 14 having a minimum arc radius of 7.62 cm and an arc width of at least
2.54 cm in a
region including the top portion of each rung, with a straight flange 15 on at
least one side of
the aro-shaped portion, wherein each rung end includes an integral, stand-off
projection 6,
each rung is sized identically with the other rungs of the ladder, and the
rungs both stack and
nest to a high degree in the collapsed state of the ladder.
Fig. 8 illustrates a perspective view of the ladder of the present invention
when in the
non-deployed, collapsed state and bound by a cover 16 having a handle 17. The
handle aids
in picking up the ladder with one hand (as, for example, from a storage box)
and in dropping
the ladder rungs as a group (once the attaching member 2 has been hooked over
the window
sill using the other hand) in order to deploy the ladder in a tangle-free
manner during a fire or
other emergency;
Figs. 9A and 9B illustrate a mounting plate 18 that may be mounted to a wall
beneath
a window sill (not illustrated). The mounting plate 18 may be mounted with
fasteners such
as screws (not illustrated) through holes 19, and may display a label (not
illustrated) . The
label is for marking the window as an exit route for use as a secondary means
of escape
during an emergency, such as a fire. On the mounting plate 18 are two openings
which may,
for example, include support collars 20 for receiving the open ends of the
attaching member
2. The openings and/or support collars allow the ends of the tubular material
of the
attaching member to be inserted and prevent motion of the ends in all radial
directions. The
arrows in Fig. 9A illustrate the direction in which the open ends of the
attaching member 2
are inserted into the support collars 20. Fig. 9B illustrates the attaching
member 2 with its
open ends fiilly inserted into the openings in the support collars 20 of the
mounting plate 18
so as to. fix the open ends from moving in any radial direction.
The mounting plate 18 may serve as many as three functions. First, it may
label the
window as an exit so that the occupants of the bufiding may be reminded that
the window
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has been designated as a secondary escape route during a fire or other
emergency. Second,
it supports the open ends of the attaching member so that the attaching member
may be
securely positioned on the window sill. Third, it provides a universal fitting
which ensures
that the attaching member 2 will seat properly over almost any design of
window sill,
regardless of the thickness of the wall.
Figs. l0A and l OB illustrate the two opposite surfaces of a cover 16, of
rectangular
shape, useful for storing and deploying a ladder designed for use from a
second-floor
window. Because of the high degree of nesting of the rungs of the ladder
according to the
present invention, the stack of rungs for a ladder for use from a second-floor
window
measures only about 15.24 cm in height, there being about 11 - 12 rungs for
such a length of
ladder. The figures show the cover in a flat, laid-out position, and give the
dimensions of the
cover 16 and the positioning of the handle 17 as well as the locations of
various sets of
temporary fasteners which enable the cover to perform three fimctions, as
discussed below.
A first function of the cover is to wrap securely around the entire ladder
including the
multiple rungs and the attaching member so that the ladder 1 may be lifted
with one hand to
a window from which it is to be deployed. A first set of temporary fasteners
21 (formed, for
example, of mating hooks and loops and sold under the name VELCRO) are
positioned near
opposite ends of the cover, and on opposite sides of the cover, as shown
respectively in Figs.
l0A and l OB. Fig. i0A illustrates the side of the cover that has the handle
17 attached, and
this side is the side that is visible in Fig 8. Fig. l OB illustrates the
opposite side of the cover
from that shown in Fig. 10A. The temporary fastener 21 at the bottom and on
one side of
the cover attaches to, and is detachable from, a mating temporary fastener 21
at the top and
on the other side of the cover. This enables the ladder 1, including both the
multiple rungs 5
and the attaching member (with the open hooks of the attaching member looped
over the
stack of multiple rungs, as shown in Fig. 8) to be picked up with one hand via
the handle 17.
The user's other hand then is free to pull apart the temporary fasteners 21 so
that the cover
opens partially to allow the attaching member 2 with the attached narrow
fabric supports 4
(down to the top rung) to be lifted from the stack of multiple rungs and
positioned in place
on the sill of the window. To facilitate the placement of the attaching member
over the
window sill the mounting plate 18, shown in Figs. 9A and 9B, may optionally be
employed.
The second fimction performed by the cover is to support the multiple rungs of
the
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ladder using the handle once the attaching member has been removed from the
cover by
releasing the temporary fasteners 21. This function is enabled by a second set
of temporary
fasteners 22 that hold the remainder of the cover so as to securely wrap the
stacked and
nested ladder rungs, thereby enabling the multiple stacked and nested rungs to
be maintained
in an organized packet during and after placing the attaching member 2 over
the window sill.
The two sets of temporary fasteners 22 (which also may be formed, for example,
of mating
hooks and loops) are positioned a distance inward from each end of the cover.
After
positioning the attaching member 2 securely over the window sill using one's
free hand, the
hand holding the handle is then positioned outside the window and, after
ensuring that the
narrow fabric supports have not inadvertently become twisted, the cover is
merely dropped
by releasing the handle in order to fully deploy the ladder.
The third fimction of the cover is to allow the momentum of the falling set of
multiple, stacked rungs to pull apart temporary fasteners 22 on the cover so
as to allow the
rungs to automatically deploy after the handle is dropped. As illustrated in
Figs. l0A and
IOB, for a two-story ladder, the cover measures about 20.3 cm by 52.7 cm, and
the
temporary fasteners 22 are positioned about 7.6 cm (Fig. l0A) and 10.2 cm
(Fig. lOB) from
the ends of the cover, in the long dimension.
Figs. 11A and 11B illustrate two opposite surfaces, respectively, ofthe cover
16 for
a ladder 1 designed for use from a third-floor window when in a flat, laid-out
position, and
shows the positioning of the sets of temporary fasteners 21, 22 on each of
these surfaces of
the cover. Because of the high degree of nesting of the rungs of the ladder
according to the
present invention, the stack of rungs for a ladder for use from a third-floor
window measures
only about 30.5 cm in height, there being about 12 - 24 rungs for such a
length of ladder. As
illustrated in Figs. 11A and 11B, for a ladder for use from a third floor, the
cover measures
about 20.3 cm by 81.3 cm. The set of mating temporary fasteners 21 are
positioned as
indicated, on opposite sides and at opposite ends of the cover. Each of
temporary fasteners
22 is positioned about 7.6 cm (Fig. 1 lA) and 10.2. cm (Fig. 11B) from the
ends of the
cover, in the long dimension as illustrated, so that the cover securely wraps
the multiple
rungs even after the attaching member 2 has been removed from within the cover
by
detaching the temporary fasteners 21.
The ladder may be readily deployed from the collapsed state by a single
individual
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using the cover in the following manner. First, the cover 16 is partially
opened by releasing
the first set of temporary fasteners 21. Then, while holding the handle 17
with one hand, the
attaching member 2 is lifted (using one's other hand) from the stack of
multiple rungs and
placed over a window sill. Then, while maintaining an orientation of the cover
such that the
narrow fabric supports between the attaching member and the top rung are not
twisted, the
handle is held out the window and dropped. The ladder is then automatically
deployed by
the momentum of the falling multiple ladder rungs reaching "the end of their
rope" so to
speak.
Industrial Applicability
The invention has use not only in the home, but in any multiple floor building
where
the occupants need a second, alternative escape route to reach safety.
The invention being thus descn'bed, it will be obvious that the invention can
be varied
is many ways. For example, all of the rungs need not be made of the same
material or be of
the same general form. Such variations are not to be regarded as a departure
from the spirit
and scope of the invention, and all such modifications as would be obvious to
one skilled in
~e art are intended to be included within the scope of the following claims.
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1- ladder
2 - attaching member
3 - support bar
4 - narrow fabric supports)
- rung(s)
6 - stand-offprojection(s)
7 - slot(s)
8 - end (of rung)
9 - rivet
- clip
11 - fastener
~eauence Listing Part of Desc 'rmtion
12 - slits (in narrow fabric support(s))
13 - spring member
14 - aro-shaped portion
- straight flange
16 - cover
17 - handle
18 - mounting plate
19 - holes
- support collars
21 - temporary fasteners)
22 - temporary fasteners)
PCT/US99/10031
