Note: Descriptions are shown in the official language in which they were submitted.
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This invention rela-tes to mattresses and in particular
to sleeping bays incorporating a mattress.
Sleeping bags which include a mattress portion are
well-known in the art per se. For e~ample, in Canadian Patent
No. 191,612 which issued to B.E. Blockson on 15 July 1919 teaches
a sleeping bag comprising a body covering and a mattress forming
the bottom of -the bag. 'I'he mattress portion comprises a pocket
filled with fibre-fill material. This type of insulation is
highly compressible and is satisfac-tory for the body covering
O portion. However, the mattress por-tion is vertically compressed
by the weight of the user and effectively provides little insula-
tion. The required clegree of insulation may be achieved by adding
more insulating material below the user. This may be either
compressible materials such as down, feathers, fibre-fill, open-
cell foam or incompressible ma-terial such as closed-cell foam.
Infla-ted structures are also used. Adding additional compressible
insulating material results in additional weight with little
return in additional insulating value. Adding incompressible
material, usually in the form of a separate foam pad,results in
O increased insulating value but the packed volume is high. Inflat-
able structures are heavy, inconvenien-t and unreliable.
The foam pad concept is described in Canadian Patent No.
866,09~, which issued 16 March 1971 to J~ Chapuis. This teaching
involves a composite laminate structure including a number of
layers of different foam materials which is substantially incom-
pressible under body weight. However, -this composite structure
is not horizontally compressible and -thus requires a large packing
volume which is particularly inconvenient from a transportation
standpoint.
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According to -the invention, a heat insulatiny ma-ttress
is con-templated, comprising body support means which is substan-
tially incompressible under body weight in a vertical direction;
and heat insulating means associated therewith, so constructed
and arranged such that said ma-ttress is compressible in a horizon-
tal direction to facilita-te packing.
A sleeping bag incorporating the mattress according to
the inven-tion is also contemplated. Several embodiments of com-
posite material mattress structures are contemplated, according
to the temperature conditions in which -the improved sleeping bag
is to be used.
In the drawing which serves to illustrate embodiments
of the invention,
Figure 1 is a side elevation in section illustrating an
improved sleeping bag according to the invention,
Figure 2 is a side eleva-tion in section of one embodi-
ment of a mattress for use in conjunc-tion with an improved sleep-
ing bag according to the invention,
Figure 3 is a side eleva-tion in section of another
~o embodiment of a mattress for use in the invention,
Figure 4a is a plan view in section of ye-t another
embodiment of a mattress for use in the invention,
Figure 4b is a perspective view of the Figure 4a arrange-
ment illustrating its construction,
Figure 5a is a plan view in section of yet another embodi-
ment of a mattress for use in the invention, and
Figure 5b is a side elevation in section of the same
embodimen-t shown in Figure 5a illustrating the optional pad.
Referring specifically to the drawing, in Figure 1 it is
seen that the improved sleeping bag according to the invention
includes a body covering portion 10 typically filled wi-th a com-
pressible insula-tion material such as feathers, down, fibre-fill
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or open-cell foa~n; and a mattress portion 12 sho~n ln sections
w:ithin a pocket 1~ sewn into -the bay. For packing, the rnattress
sections are removed from the pocket, s-tacked, horizontally com-
pressed and fitted into a transpor-t container not shown.
In the embodiments of the ma-ttress shown in Figure 2, it
is seen that the mattress 12 is formed of alternating strips of
closed cell foam 16 material such as polye-thylene and polystyrene
and open-cell foam 18 such as polyurethane. The closed cell foam
is substantially incompressible and provides support for body
weight in a vertical direction B. The open cell foam is compres-
sible and permits horizontal compression of the mattress 12 in
direction A to facilitate packing. The alternating strips of
closed cell foam 16 and open cell foam 18 are glued together
along their butt-joined surfaces by a suitable adhesive such as
7~ Foam and Fabric Adhesive manufactured by 3 ~ or BOSTIC ~
HOT MELT GLUE. In the embodimen-t illustra-ted in Fig-ure 2, the
closed cell foam is shown on the outside. I-t is also contemplated
that the open cell foam may form the outside. Many other combina-
tions of closed- and open-cell composite foam materials are possi-
ble and their geometric arrangement is unimportan-t, provided that
the reyions of closed-cell foam do not form a rigid lattice net-
work which is hori~on-tally incompressible. There is no require-
ment for -the closed-cell foam to be flexible in this embodiment.
Additionally, although the foam strips 16 and 18 are illustrated
as running the leng-th of the mattress, they may also be arranged
to run across the width of the mattress.
The relative dimensions of the various pieces of the
different foam materials are not critical. To give a reasonable
lateral compressibility the relative areas of open and closed
should be about 5 to 1. To provide even, comfor-table support to
the user, the distance between adjacen-t pieces of closed-cell
foam should not be more than about 10 cm. A system of alterna-ting
strips of the two foams wi-th widths of 5 cm and 1 cm has proved
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convenien-t. These composites are readily made by cutting bulk
pieces of the different foams ln-to -the desired shapes and gluing
the pieces together.
In the Figure 3 embodiment the open-cell foam may be
replaced with a loose particulate insula-ting Eiller material 18a
such as polyester fibre-fill, down and feathers, which provides
the re~uired horizontal compressibility in direction A. A suitable
textile fabric envelope 20 such as a 60 g/m2 rip-s-top nylon is pro-
vided to maintain posi-tioning of the closed cell foam elements 16
and the particulate material 18a. The foam elements may be
glued -to the textile fabric usiny the same adhesives described
above. In this emkodiment -the foam strips are spaced apart about
twice their width. As in the figure 2 arrangement, the foam
s-trips 16 may be arranged across the width of the mattress.
Turning now to Figure 4, an embodiment named the
"egg-crate" which exhibits appropriate horizontal flexibility at
moderately low temperatures (O to -~OC) is illustrated in Figures
4a and 4b. This arrangement comprises a flexible lattice network
of strips of a suitable flexible closed-cell foam material 16~.
The foam material must be flexible -to permit flexing or compression
in a horizontal direction A. Note that this version is compres-
sible in any horizon-tal direction ~. Brit-tle closed cell foams
such as polys-tyrene tend to break when flexed to any significant
extent, especially a-t low temperatures. Closed-cell polyethylene
foam has been found suitable. Closed-cell ethylene vinyl ace~ate
foam is also contemplated. The pockets be-tween the foam strips
16a are Eilled wi-th a suitable loose heat insulating material 18a
such as polyester fibre-fill, down, feathers and the like. As
shown in Figure 4b, the foam strips are connected in interlocking
fashion. As in the Figure 3 arrangement, a suitable textile
fabric envelope 20 is provided for maintaining positioning of the
flexible lattice structure and to close the open-ended pockets
therebetween to retain the loose insulating material. The foam
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strips are glued along their exposed edges -to the textile material
using the same adhesives described above. The flexible lattice
arrangement illus-tra-ted comprises 10 cm square pockets. The
foam strips are conveniently about 1 cm -thick and abou-t 5 cm
wide, to provide a ma-ttress element about 5 cm thick. Other
yeometric networl~s could be used such as circles and hexagons,
provided that ho:rizontal compressibility is maintained.
Refer~ing to Figures 5a and 5b, an embodiment called
the "bed of nails" is illustrated. This version shows adequate
hori~on-tal compressibili-ty at ex-tremely cold temperatures i.e.
down to -40C. The nail elements 16b of a suitable closed-
cell foam materlal such as closed-cell polyethylene are evenly
spaced about the same distance apart as their dimension. Other
closed cell foam materials such as polystyrene may also be used
since the same degree of flexibility is not required in this
arrangement as in the Figure 4 arrangemen-t. The nail elements
are arranged in a textile fabric envelope 20 and surrounded by
loose heat insulating material 18a as described in the previous
embodiments. The nail elements 16b are glued to the textile
fabric 20 at their exposed ends by the same adhesives described
previously.
The dimensions of the "nails" are dictated by the
thic~ness of the mattress. They must be approximately cubic to
suppor-t body weight without bending or toppling. The inter~nail
spacing is of the same order of magnitude as the nail dimension
to provide for a reasonable compromise between compressibility
and evenness of support. The resulting mattress is therefore
rather bumpy and uncomfortable, though thermally adequa-te. To
allevia-te this discomfort an optional layer 22 of suitable closed-
cell foam such as closed-cell polyethylene foam is added on top of
the mattress as shown in Figure 5b. The additional layer 22 is
conventionly about 1 cm thick.
In this embodimen-t, both -the mattress and the additional
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foam layer 22 are enclosed :in a poclcet in the bottom of thesleeping bag. The foam layer is removed for packiny but the pad
can stay in the hag which can then be compressed and s-tuffed into
i-ts carxyin~ case. The mattress need not, -therefore, be con-
structed in sections but may be one long piece and may be built
into the sleeping bag permanently rather than belng made removable.
The advantage of a removable mattress is that -the various pieces
of the bag may be laundered, repaired or replaced separately.
The "nails" may also be in other shapes such as cylinders of
appropriate dimensions.
Overal1 Dimen_ions
The length of the mattress is the length of the bag
or the height of -the user, typically 190 cm.
The width is the minimum consisten-t with comfort so as
to minimize packed volume. We find 42 cm to be acceptable though
a large person mi~ht require more width~ 40 to 50 cm is a
reasonable width range.
The thiclcness of the mat-tress depends on the temperature
of the ground on which it is to be used. Above 0C, 2 cm is
adequate and at -40C, about 6 cm required. There is probably
little poin-t in using complicated/ and therefore expensive, con-
struction techniques for warmer applications when simple layers
of foam are adequate. Although it might be desirable to have
very thick pads at low temperatures, the packed volume acts as a
constraint. A thickness range of 3 to 8 cm thickness is therefore
realis-tic.
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