Note: Descriptions are shown in the official language in which they were submitted.
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DOOR SILL COMPOSITION
Technlcal Field
The present invention deals broadly with doors providing
access to a building such as a residential dwelling. More
specifically, however, the invention deals with sills for
sliding doors such as doors to patios, decks, etc. The
specific focus of the invention is the overall composition of a
sill for such a door.
Backaround of tha Invention
Sliding doors such as ones providing egress, for example,
from a residential dwelling to a patio or deck are well-known
in the prior art. Such prior art is fairly well developed.
Sliding doors hnving been in existence for a considerable
period of time. Typically, such door~, which are known a8
French doors, are utilized to provide access, as indicated
above, to patios, decks, etc. from residences with whieh such
patios, decks, etc. are associated.
Of serious concern in the manufacture of doors in general
and, particularly, sliding doors, is the sill structure. The
sill i8 the portion which provides the threshhold over whieh
one passes when passing through the door elosure.
In the case of sliding doors, sills provide unique
problems. They must be resistent to chemieal action which
might result from exposure to ultraviolet light. Additionally,
they must be strong and durable, since traffic across them ean
be quite significant.
In the prior art, various materials have been employed in
the manufacture of sliding door sills. Wood is one particular
composition which has been employed. Wood, however, deeays
over a period of time, since wood absorbs moisture. Even when
decay is slow 90 that the useful life of a sill i8 obtained,
warping can occur. Warping, if significant enough, ean create
a safety hazard. At a minimum, however, it gives rise to an
unsightly condition.
.
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Aluminum h~s been deemod to be a logical choice for a
sliding door sill application. Aluminum has been thought to
have the mo~t significant strength Çor thia application.
Stronger materials would, of course, be more desirable.
Even aside from the strength issue, however, aluminum does
have certain drawbacks. ~ecause of its inherent metallic
properties, aluminum has a relatively high coefficient of
thermal conductivity. When used in a sliding door sill
application, aluminum can conduct heat within the building in
which the door is installed to the outside. Thi8 i8 a
particularly acute problem in geographic locations where
Winters are very cold. In extreme temperature condition~, the
temperature gradient between the lnside and outside of a
building is quite extreme.
The 301ution proposed when aluminum is used has been to
provide a thermal break in order to inhibit thermal
conduction. Doing this, however, has translated to high
manufacturing costs.
It is to these dictates of the prior art and the problems
discussed above that the present invention is directed. It is
a composition for a sliding door sill which overcomes the
problem~ of the prior art, taking into account the desirable
dictates for such a product. J
Summary of the Invention
The present invention is a door sill having a particular
CompOsitiOn, The sill includes a core which defines a form.
The form i8 maae from spun glass fibers which are treated with
a polyester resin. The form thus formed is, in turn, coated
with an ultraviolet stable cladding.
In one embodiment of the invention, the core form includes
a plurality of vertically-oriented spun gla~s fiber panel~.
The vertically-oriented panels are, in turn, integrated by a
plurality of interconnecting panels.
In certain embodiments of the invention, the form can
include an unsupported cantilevered portion. Such a portlon, it
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would be intonded, would exte~d outwardly from a building in
which thc 5ill is installed. Becauso of the strength
properties afforded to the sill, the cantilevered portion
could, in fact, be unsupported.
ln the preferred embodiment, the core form would include
glass fibers oriented both in lineal rows and random mats. The
form thus constructed would provide flexing strength during
vertical load over the length of the sill. The random mat
would contribute strength against bending in the vertical
plane. As a result, the need for a sill nose support would be
eliminated.
The preferred embodiment al90 envisionB employment of an
ultraviolet stable sheathing. It is felt that an L~XAN
sheathing would be optimum 9ince such a material i8 not only
ultraviolet stable, but it i8 also resistent to impact and
abrasion.
Other claddings are, however, contemplated. Other
appropriate claddings would, further, include the
characteristics of a polycarbonate.
The present invention is thus an improved sill composition
and construction. More specific features and advantages
obtained in view of those features will become apparent wlth
reference to the DETAILED DESCRIPTION OF THE INVENTION,
appended claims, and accompanying drawing figures.
Brief Description of the Drawinq
The figure is an end perspective view of a door sill
constructed in accordance with the present invention.
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Detailed DeHcription of the Invention
~ eferring now ~ the drawing wherein like reference
numerals denote likè elements throughout the several views, the
figure illustrate~ a door sill 10 composed in accordance with
the pre3ent inventio~. While the overall qill 10 will be
described in order to provide the general background and
environment in which the present invention functions, it will
be understood that t~e specific focUs of the invention 18 the
sill structure itself.~
The figure illustrates a 3ill 10 in pogition on a block 12
of a building in which a sliding door a~Yembly, of which the
sill is a part, i9 installed. The sill assembly 14 is seated
on the block 12 with a cantilevered portion 16 of the 8111 10
extending outwardly from the block 12. A baseboard 18 i9 ln
engagement with a generally vertically-extendlng inner panel 20
of the 9ill 10.
The overall sill 10 supports an extruslon 22 which mounts a
flxed door panel 24. The door panel 24 is secured to the
extruslon 22 by means of a block 26 which is received wlthin a
channel 28 for~ed within the lower edge 20 of the fixed door
panel 24.
A sliding door panel 32 is mounted to a track 34 for
longitudinal movement therealong between open and closed
dispositions. A pile seal is 26 engaged by the botto~ edge 38
of the sliding door panel 32 to in~ulate, when the door panel
32 is in a clo3ed disposition, the inside of the building in
which the door 14 is mounted, from the exterior. Additionally,
a weather seal strip 40 is mounted to the track 34 along which
the sliding door panel 32 moves to 3eal along the bottom edge
38 of the sliding door panel 32 when that panel 32 i9 in its
closed di 5pO9 i tion.
The flgure al~o illustrates a ~liding screen door 42
mounted to a track 44 extending upwardly from a cantilevered
portion 16 of the sill structure 10. In fact, the screen door
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42 i~, typically, suspended by an upper rail thereof ~not
shown) from an upper track (not shown). The lower rail 46 of
the screen door panel 42 interface3 with the lower track 34
merely for alignment purposes and to inhibit the passage of
mud, snow, ice, etc.
As seen in the figure, the sill structure 10 comprises two
components, a core 48 and a cladding 50. The core 48 primarily
functions to provide structural integrity, rigidity, and
strength to the sill 10. The cladding 50 functions primarily
to present a surface 52 exposed to the elements and which is
protective against those elements. Typically, the cladding 50
is impact and abrasion resistant. Further, it is ultra-violet
stable in view of the fact that the sill 10 is usUally exposed
to solar radiation.
The core 48 in accordance with the present invention is
formed from spun glAss fibers, Those fiber~ are treated with a
resin binder. Shape is given to the core 48 by manufacturing
it through a proces known a~ "pulltrusion". The process is
similar to extrUsion, but the thrust of the force is applied to
draw the item through the die from a side of the die after the
item has been formed. This i9 a corollary to a standard
extrusion proce~s.
i The core 48 comprises a form which includes a plurality of
generally vertically-oriented panels 54 which provide support
in a vertical plane. The generally vertically-oriented panels
54 are interconnected by a series of transverse panels 56, the
core 48 thereby being provided with form and shape.
The core 48 includes a generally horizontalIy-disposed
cantilever portion 58. The core 48 cantilever portion 58
serves as a foundation for the overall cantilver portion 16 of
the sill 10.
In the preferred embodiment of the invention, the core 48
includes glass fibers which are oriented both in lineal rows
and random mats. A core 80 constructed provides flexing
strength during vertical load over the length of the sill 10.
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The fibers formed into a random mat function to contribute
strength again~t bending in the vertical plane. That i8, they
provide strength against torqua forcos applied, for example, to
the cantilever portion 16 of the 8ill 10. secause of the
random fiber matting, the cantilever portion 16 of the sill 10
need not be 9upported.
The sill further includes a cladding 50 which coat3 the
core 48. It is important that the cladding 50 provide
ultraviolet 5tability 80 that chemical breaXdown does not
occur. Further, the cladding S0 should be resistant to both
impact and abrasion. Typically, any material having
characteristics of a polycarbonate could appropriately function
as the material for the cladding 50. It has been found,
however, that LEXAN i8 particularly appropriate to function for
thi9 purpose. It wili b0 understood, however, that other
metals can, additionally, be appropriately used as the cladding
material.
As seen in the figure, the inner surface 60 of the cladding
50 generally conforms to a shape defined by various panels 56
of the core 48. The cladding 50 can, thereby, be fitted
closely over the core ~8 and be made 3ubstantially an integral
structure.
Numerous characteristics and advantages of the invention
have been set forth in the foregoing description. It will be
understood, of course, that this disclosure is, in many
respects, only illustrative. Changes can be made in details,
particularly in matters of shape, size, and arrangement of
parts without exceeding the scope of the invention. The
invention's scope is defined in the language in which the
appended claims are expres~ed.
