Note: Descriptions are shown in the official language in which they were submitted.
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INFLATABLE l.IFSRAFT
The invention relates to liferafts.
A known form of liferaft comprises two members connected by an
inflatable structure which, when inflated, separates the
members to form an enclosure, with one member forming a
generally planar floor and the other member forming a
generally planar roof to the enclosure. An example of a
liferaft of this type is shown in US-A-3037218.
One problem with a liferaft of this type occurs on inflation,
particularly inflation under water. As the inflatable
structure inflates, the floor and roof members are initially
deployed in their planar configurations. The member that
forms the roof can be covered with significant quantities of
water and the weight of this water can be such as to prevent
the inflatable structure inflating properly and deploying the
liferaft.
According to a first aspect of the invention, there is
provided a liferaft comprising two members connected by an
inflatable structure, which, when inflated, separates the
members to form an enclosure, with one planar member forming
a generally planar floor and the other planar member forming
a generally planar roof to the enclosure, a passage being
provided between the first and second members, the passage
being open as the inflatable structure inflates to allow water
to drain from the surface of the planar member.
It is also a problem both with liferafts of the type shown in
US-A-3037218 and with other liferafts, that evacuees need
assistance in boarding the liferaft. It has previously been
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proposed to provide boarding ramps which project from the
liferaft and up which evacuees can crawl to gain access to the
liferaft. The projection of such boarding ramps from a
liferaft can be a problem because they can interfere with the
deployment of adjacent liferafts and, in addition, many of
them may not be needed because, where there is more than one
entrance, not all entrances may be used.
According to a second aspect of the invention, there is
provided a liferaft comprising an inflatable structure and an
entrance ramp including at least one inf latable member, the
inflatable member being in communication with the inflatable
structure, the boarding ramp being held in a collapsed
disposition and being releasable from said collapsed
disposition, the release permitting the inflatable member to
inflate with gas from the inflatable structure to deploy the
boarding ramp.
The following is a more detailed description of some
embodiments of the invention, by way of example, reference
being made to the accompanying drawings in which:-
Figure'1 is a plan vieww from above of a deployed liferaft--
showing drainage passages and projecting boarding ramps,
Figure 2 is a side elevation of the liferaft of Figure 1,
viewed in the direction of the arrow X in Figure 1,
Figure 3 is a side elevation of the liferaft of Figure 1
3o viewed in the direction of the arrow Y in Figure 1,
Figure 4 is a cross-section on the lines A-A of Figure 2,
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Figure 5 is a plan view of one of the drainage passages shown
in Figure 1,
Figure 6 is a side elevation of the drainage channel of Figure
5,
Figure 7 is a partial cross-section through a tube of the
liferaft of Figures 1 to 4 showing one of the boarding ramps
in a collapsed disposition and held against the tube by two
sheets of material,
Figure 8 is a similar view to Figure 7 but showing the
boarding ramp in a deployed disposition, and
Figure 9 is a partial side elevation of the liferaft in the
direction shown in Figure 2 and showing the deployed boarding
ramp to a larger scale.
Referring first to Figures 1 to 4, the liferaft is generally
octagonal in plan view with two opposed side walls 10, two
opposed end walls 11 and four corner walls 12 interconnecting
the end walls and the side walls. As seen in Figures 2 and 3,
the walls are formed by an inflatable structure including six
stacked inflatable tubes 13a-13f. The two uppermost tubes
13a,13b and the two lowermost tubes 13e,13f are continuous
around the liferaft. Each of these tubes, 13a,13b,13e,13f
thus has eight corners 14. The corners of all the tubes
13a,13b,13c,13d,13e,13f are thus vertically aligned. The two
remaining tubes 13c,13d are discontinuous at the side walls 10
and the end walls 11 to form opposed side entrances 15 and
opposed end entrances 16, respectively.
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The tubes 13a-13f are formed from a rubberized fabric material
in known fashion. Accordingly, their construction will not be
described in detail. Each entrance includes a doorway formed
by a sheet 17 of rubberized fabric provided with a securable
cover 18 that can be rolled back, as seen in Figures 2 and 3.
Each side entrance 15 is associated with a respective pair of
boarding ramps 19. The construction and operation of these
boarding ramps 19 will be described in more detail below.
l0 The uppermost tube 13a and the lower most tube 13f are each
provided with a respective succession of water pockets 20
extending around the associated tube 13a,13f. As shown, there
are 32 water pockets 20 on each tube 13a,13f. These water
pockets 20 are of conventional design.
The liferaft is also provided with a floor 21 and a roof 22.
The floor 21 and the roof 22 are both made from rubberized
fabric material of suitable strength. In this regard, it will
be appreciated from the description of the drawings above and
from the drawings themselves that the liferaft is reversible.
The floor 21 could act as a roof and the roof 22 could act as
a floor.
The periphery of the roof 22 is sandwiched between the
uppermost tube 13a and the next adjacent tube 13b. The
periphery of the floor 22 is sandwiched between the lowermost
tube 16f and the next adjacent tube 16e.
As seen in Figure 4, the roof 22 and the floor 21 are
separated within the liferaft by an inflatable internal
structure comprising two pairs of cross beams 23, with the
beams 23 of each pair separated by three spaced vertical
columns 24. The beams 23 and the columns 24 are formed by
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inflatable tubes of known design. As seen in Figure 4, one
cross beam 23 of each pair extends across the floor 21 between
the side walls 10 and the other cross beam 23 of each pair
extends across the roof 22 between the side walls 10. The two
5 pairs of cross beams 23 are spaced apart along the length of
the liferaft.
The roof 22 and the floor 21 are provided with respective
circular entrances 25 in register with one another. These
entrances 25 are interconnected by a tube including a slanting
diverter (not shown). The tube can be open to allow access
into the interior of the liferaft . The entrance 25 on the
roof 22 is designed to be connected to an escape chute of the
kind shown in our PCT Application Publication No. WO 97/22514.
Accordingly, this will not be described in any further detail.
The roof also includes three attachment points 26 by which gas
cylinders may be mounted on the roof for supplying gas to the
inflatable structure via an inflation system (not shown) of
conventional type.
There are also four tubes 27 extending between the roof 22 and
the floor 21. These are to allow the drainage of rain water
from the roof 22 and these tubes 27 may be provided with
valves and outlets to allow such rain water to be collected
and used as drinking water.
The roof 22 and the floor 21 are also provided with three
drainage passages 28. One such passage 28 is shown in Figures
5 and 6. With reference to those Figures, each passage 28
comprises a tubular sleeve 29 of flexible foldable material
extending inwardly from an aperture 30 in the floor/roof
21/22. The aperture 30 is covered by a circular mesh 31. The
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end of the sleeve 29 remote from the mesh 31 is provided with
a draw string 32.
The drainage passages 28 in the roof are in register with
drainage passages 28 in the floor 21. Before the inflatable
structure is inflated, the sleeves 29 of-all the drainage
passages 28 are rolled back so that they leave the associated
apertures unobstructed. Each drainage passage 28 in the roof
22 is then connected to the registering drainage passage 28 in
the floor 21 by breakable threads 40 to form a continuous
passage between the roof 22 and the floor 21. The purpose of
this will be described below with the description of the
deployment of the liferaft on inflation.
As seen in Figure 1, two drainage passages 28 are located on
a lateral axis 38 of the roof 22, each adjacent a respective
side entrance 15. The third drainage passage is located on a
longitudinal axis 39 of the roof 22 adjacent the intersection
of this axis 39 with the lateral axis 38.
The boarding ramps 19 are located adjacent the side entrances
15. Referring to Figures 1, 2, 3 and 8, each boarding ramp 19
comprises a U-shaped inflatable tube 33 connected at the base
of the U to either the uppermost tube 13a or the lowermost
tube 13f. This base of the U-shaped tube is in gas
communication with the associated tube 13a/13f. The space
between the limbs of the U is filled with a mesh material 34.
As also seen in Figures 2 and 9, two straps 35, forming hand
grips or foot rests, are arranged between each boarding ramp
19 and the adjacent side entrance 15.
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As best seen in Figures 1 and 2, there are two boarding ramps
19 associated with each side entrance 15. One boarding ramp
19 extends radially from the upper tube 13a and the other
boarding ramp extends radially from the lower tube 13f. The
boarding ramps 19 are on respective opposite sides of a
vertical plane passing through the centre of the side,
entrances 15. Thus, there is provided a boarding ramp 19
usable whichever way the liferaft falls.
As seen in Figure ?, when deflated, the U-shaped tube 33 and
the mesh material 34 are rolled up against the associated tube.
13a,13f. They are held in this position by a retaining device
formed by two sheets of material 36,37 attached at spaced
points to the adjacent tube 13a,13f. The first sheet 36 wraps
around the folded boarding ramp 19 and then connects to the
second sheet 37. This connection may be by any releasable
device such as the engaging hooks and eyes sold under the
trade mark VELCRO. Thus, when the sheets are separated, by
being ripped apart by an evacuee, the pressure of air from the
associated tube 13a,13f inflates the U-shaped tube 33 and
deploys the boarding ramp 19. The volume of the U-shaped tube
33 is so small in comparison with the volume of the associated
tube 13a,13f as to make little difference to the rigidity of
the associated tube 13a,13f.
In use, the liferaft is deflated and packed and stored on an
appropriate vessel. As mentioned above, it may be associated
with an escape chute of the kind described in WO-A-97/22514.
When required, the liferaft is thrown from the side of the
vessel and, as it hits the water, the inflation system is
actuated automatically. Thus, gas from the cylinders mounted
on the attachment portions 26 of the roof 22 is supplied to
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the inflatable structure. This happens very quickly and the
first effect is to form the upper and lower tubes 13a,13f into
their octagonal shape so spreading the floor 21 and the roof
22 into their octagonal shapes. This may occur when the
liferaft is wholly or partially under water or when the
liferaft is being covered by high seas. As the roof 22 is
spread, water will collect on the roof 22. The weight of this
water may be sufficient to withstand the forces of the
expanding inflatable structure.
This problem is overcome by the drainage passages 28. They
are of sufficient size, number and location that water passes
through these passages from the roof 22 to the floor 21 and so
prevents such water inhibiting the inflation of the inflatable
structure.
In this regard, it will be appreciated that there is less
inflatable structure at the side entrances 15 than elsewhere
in the liferaft. The liferaft will thus have a tendency to
fold around the lateral axis 38 extending between these side
entrances 15. Thus, the drainage passages 28 located adjacent
the side entrances 15 convey water from these areas. In
addition, the interconnection between the passages 28 tends'to
trough the roof 22 in the centre of the liferaft so collecting
the water in the region of the passages 28.
As the pressure within the inflatable structure increases; the
threads extending between the registering drainage passages 28
are broken and the inflatable structure continues inflating
until it is fully deployed. This separates the sleeves 29 to
break the passage between the roof 22 and the floor 21. By
this time, all significant water will have been drained from
the roof 22 and the drainage passages 28 are no longer needed.
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The use of a polygonal shape with registering corners to the
tubes 13a-13f provides a rigid structure since the corners are
stiffer than the remainder of the tubes 13a-13f.
Evacuees then board the liferaft preferably through the escape
chute entrance 25. If, however, there are evacuees in the
water, they can release the boarding ramps 19 as described
above and clamber aboard using the straps 35 and the side
entrances 15. They can also use the end entrances 16.
Once within the enclosure formed by the liferaft, the evacuees
can close the drainage passages 28 by use of the drawstrings
32. Those passages 28 in the floor can be used as balers.
The tubes 27 can be used to collect water.
It will be appreciated that there are a number of variations
that can be made to the liferaft described above with
reference to the drawings.
The liferaft could have any convenient shape. This need not
be a polygonal shape, -it could be a circular shape. There may
be more or less entrances. The boarding ramps 19 are
optional. There may be more or less drainage passages 28.
The drainage passages 28 could be constantly continuous
between the roof 23 an the floor 21 even when the liferaft is
fully deployed. The drainage passages 28 may be located other
than as shown.
The boarding ramps need not be used on a liferaft of the kind
described above with reference to the drawings; they could be
used on any suitable liferaft. The boarding ramps could have
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any required configuration, they need not be formed by a U-
shaped tube and a mesh. Any form of inflatable tube or tubes
could be used with the structure receiving gas from an
adjacent inflatable structure.
5
