Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
11'~961~
THERMAL INSULATING SYSTEM
Background of the Invention
1. Field of the Invent_on
The invention relates to a thermal insulating
system of foamed plastic sheets having tongue and groove
profiles on the narrow sides with a flexible foam strip
being inserted in at least one of the grooves.
2. Descri~tion of the ~rior Art
Tough, hard foamed plastics, for instance based
upon polystyrene foam, are used on a large scale for
insulating buildings and building elements, primarily roofs,
against thermal influences. They naturally are relatively
rigid. As a result of this high mechanical rigidity, the
installation of sheets of tough, hard rigid foams as thermal
insulation between roof rafters, fc)r instance, is much more
difficult and time consuming than t:he installation of
flexible ~lastic fiber insulating Materials. Since the
distance between the rafters within one area, and even from
area to area, is not uniform due to inaccurate installation
and warping of the rafters, every individual sheet must be
cut. By shrinkage or thermal contraction of the rigid foam
sheets, by changes in the form of the support construction,
thermal bridges or cracks may develop in the roof insulating
sheets.
A purpose of this invention was to reduce the
rigidity of sheets of tough, hard foamed plastic in at least
one direction parallel to the main plane, without, however,
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impairing the other properties, particularly the thermal
insulation, the dimensional stability of the sheets in the
installed state and the rigidity (resistance to compression)
perpendicular to the main plane of the sheets.
In sloped roofs, the distances of the rafters vary
within wide ranges between approximtely 35 and 75 centi-
meters. ~hen installing the above-mentioned thermal
insulating sheets for the purpose of roof insulation,
several sheet widths must therefore be available. However,
since it is irnpossible to make available an infinite variety
of sheet widths, the sheets must be cut to correspond with
the actual distance between rafters such as under actual
installation conditions. This results in material losses by
the installer and necessitates disposal of the waste
pieces. The sheet manufacturer is forced to produce several
sheet types with various widths and for the dealer, this
results in costly warehousing. All of this, of course, is
reflected in the costs.
Another purpose of this invention was therefore
the development of a thermal insulating system with which
the foam sheets can be installed without considerable
material losses independent of the distance between the
rafters.
Summary of the Invention
This invention relates to a thermal insulating
system of a multitude of rectangular thermal insulating
sheets of a tough, hard foamed plastic having a density of S
--2--
1~2~)1g
grams per liter to 100 grams per liter, preferably 10 grams
per liter to 50 grams per liter. These sheets are equipped
with tongue and groove profiles on all four narrow sides,
the tongue and groove in each case, are opposite each other
and with a strip of a flexible elastic foam being inserted
in at least one groove of the sheets. The thickness of the
foam sheets is between 2 centimeters and 31 centimeters,
preferably between 5 centimeters and 15 centimeters and
particularly between 8 and 12 centimeters. The sheets are
40 centimeters to 200 centimeters wide, preferably 5
centimeters to 80 centimeters, and their length is 40
centimeters to lO00 centimeters, preferably 50 centimeters
to 125 centimeters.
The depth of the groove aclvantageously is greater
than the length of the tongue and the total of the length of
the tongue and the thickness of the flexible foam strip is
appropriately greater than the depth of the groove.
Descriptlon of the Preferred Embodiments
The drawings show schematics of a particular
preferred version of the thermal insulating panel according
to this invention as well as two installation principles.
Now, referring more particularly to the drawings,
Figures la through d show the side view of two respective
thermal insulating sheets with different versions of the
groove G and the tongue T as well as the flexible foam
strip F.
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Figure 2a shows the installation e~ample a) where
the sheet width B (62.5 centimeters including tongue) is
less than the distance between the two rafters S (75
centimeters); Figure 2b shows installation version b) where
the sheet width ~ is greater than the distance between the
rafters (55 centimeters). In both cases, the sheets have
the same length L (100 centimeters, including tongue) and
thickness (10 centimeters). The cut off sheet sections x, y
and z are separated along the separating line R and are then
used during the next installation step. The above described
addition (1 centimeter) is not taken into consideration in
the drawing, that is, the sheets are shown in the compressed
state. The measures listed in parentheses refer to a test
under actual installation conditions. A sheet, sheets
and/or a sheet section or sheet sections herein sometimes
referred to as sheets, may also be used.
The tongue and groove profile can be sawed or cut
from the foam by ~amiliæ methods. The form and the size o~
the profiles can basically be chosen as desired with, of
course, the tongue and groove correlated in a functional
manner. Tongue and groove may have a rectangular or a
conical cross-section. In order to facilitate easier
assembly, the tongue and groove preferably are somewhat
rounded.
The width of the groove preferably is approxi-
mately half the sheet thickness and its depth preferably
should be at least 3 centimeters. The overall dimensions of
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the sheet should be selected, including the tongue and
groove profiles, in such a manner that the foam blocks from
which the sheets are normally cut are used to an optimum
extent so that the waste is reduced to a minumum amount.
The flexible and elastic foam strip herein
sometimes called the flexible foam strip, may have any
desired cross-section. It may be round, oval, rectangular,
square or have an irregular shape. Dimensions and profile
of groove, tongue and strips should be adjusted to each
other in such a manner that the sheet with the tongue, which
is to be attached, can be pressed in by several centimeters
as a result of the compression effect of the flat flexible
strip so that the two sheets and/or sheet sections can be
pressed together manually until tongue and groove touch on
the one hand and that on the other hand the recovery forces
of the flexible strip cause the sheets and/or sheet sections
to sufficiently clamp between the frame construction such as
the rafters of the roof.
These effects facilitate easier fitting of the
sheets between the raftera and the insulating system can
adjust to shifting and warping of the rafters as well as
thermal contraction or expansion of the foam sheets them-
selves, thereby preventing thermal bridges as a result of
opened butting joints as well as stress peaks in cover
layers and in coverings which are installed in a stationary
manner.
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Tough, hard, foamed plstics, according to
H. Goetze "Foams", Road Construction, Chemistry and
Engineering Publishers, ~eidelberg, Page 24, are foamed
parts displaying a steadily progressing, partially
reversible deformation with increasing compressive load
without reaching a definite breaking stage of, for instance,
brittle rigid foams which fail by a sudden collapse of the
structure with rising compressive load without prior elastic
deformation.
Preferred foams are those based upon polystyrene,
more preferably, expanded polystyrene particles. Also
useful are extruded polystyrene foam, polyvinyl chloride
foam, and tough, hard, polyurethane foam and, preferably,
flexible melamine-formaldehyde foam in accordance with
German Patent Application P 29 15 457 and flexible urea-
formaldehyde foam.
Useful flexible elastic foams are preferably foams
based on polyurethanes, flexible polyvinyl chloride, or
polyethylene. More preferably used are cold cured poly-
urethane foams based on aromatic isocyanates and polyetherpolyols which may contain the commonly used polyurethane
additives such as ~atalysts, surface-active substances, and
blowing agents~
Similar to traditional insulating materials~ the
foam sheets may be coated on one or both surfaces parallel
to the primary plane of the sheet. Coating materials which
may be used are tension proof but easily bendable materials
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such as fleeces, textile fabrics or glass fibers, metal
foils or plastic foils~ and bitumin ceiling sheets.
Depending upon the material used, the coating in the
installed state serves as a reinforcement with respect to
tensile stresses, a vapor barrier and a sealing material
against drafts or water. Coating on both sides results in a
double sided reinforcement with the same additional
functions as those mentioned for the single sided coating.
The thermal insulation system of this invention is
used preferably for the thermal insulation of subdivided
surfaces, for instance, of sloped roofs where the sheets are
installed between the rafters of the roof. A differentia-
tion must be made between two conditions when installing the
sheets:
a) the sheet is not as wide as the distance between the
raters and
b) the sheet is wider than the distance between the
rafters.
a) First, a ~lexible foam strip is placed in one groove of
a sheet. Second, a second sheet is loosely fitted to
the first sheet by means of the tongue and groove joint
to form a composite sheet. If required, additional
sheets can be attached in the same manner to form the
composite sheet. The part of the composite sheet which
protrudes beyond the distance between the rafters plus
an added amount of 0.5 to 5, preferably 1 to 2 centi-
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meters is then cut from the composite sheet. The cutcomposite sheet is compressed by the added amount in a
direction perpendicular to the rafters and are inserted
between the rafters.
In a subsequent installation step, the remaining cut
part of the composite sheet is attached to another sheet
or another part of a sheet in the same manner and is cut
and inserted between the rafters.
Third~ the individual panels inserted between the
rafters are combined by connecting their tongue and
groove profile which run in a perpendicular direction to
the rafters. In this case also, a flexible foam strip
may be inserted in the groove but this is not essentialO
b) In the other case, part of the sheet, which is too wide,
is cut off creating a part narrower than the distance
between the rafters. The flexible foam strip is then
again inserted into the groove of the remaining part of
the sheet and a second sheet is attached to form a
composite sheet. ~ne then continues to proceed as
described under a) second.
By compressing the composite sheet, the sheets are
put under pressure in a perpendicular direction to the
rafters. This pressure causes the sheets to hold between
the rafters. In addition, the sheets may be fastened to the
rafters by tacks or the installation of slats. The tongue
and groove connection of the individual composite sheets in
the longitudinal direction to the rafters guarantees an
excellent fit and wind tightness.
~ 1 ~2 ~
Essentially, no material losses by wasted pieces
are incurred when the installation process described above
is used since the cut off parts of the sheets can be used
othex than very small left over pieces. Another advantage
of the thermal insulating system of this invention is that
the manuEacture of the sheets can be limited to one width.
This permits streamlining of the production process. ~he
corresponding selection of panel dimensions furthermore
guarantees optimum utilization of the foam slab. Packaging
and transport of the sheets are also simplified. As far as
the trade is concerned, the method of th is invention
results in greatly reduced and simplified warehousing. The
application of this thermal insulating system results in
advantages in planning and purchasing for the tradesman or
the do-it-yourselfer in that he can use the available sheet
width independent of the distance be~tween the rafters. The
pre-measuring of the distances between the rafters for the
detailed determination of required widths can also be
eliminated.
