Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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WEATHER SEAL CONSTRUCTION INCLUDING A WEATHER-STRIP
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application 60/602,132
filed on August 17, 2004 for inventor James L. Peterson et al. and entitled
ONE
PIECE CORNERING WEATHER-STRIP.
BACKGROUND OF THE INVENTION
The present invention relates to weather-strips and in particular relates to
weather-strips that have a sealing member made from a foamed polymer.
Presently there are several materials being used to make foamed weather-strips
for
residential windows and doors. These materials produce very satisfactory
weather-
strips.
Such weather-strips have a foamed sealing member and an attaching member that
is
used to secure the sealing member to the door or window. Typically the
attaching
member is made of a solid polymer.
One material used for the foamed sealing member in weather-strips is
SANTOPRENE~. SANTOPRENE~ is an elastomeric thermoplastic rubber which
may be foamed to produce extruded cylindrical and other profiles. The
characteristics
and properties of SANTOPRENE~ are described in U.S. Pat. Nos. 4,130,535 and
4,311,628 assigned to Monsanto Company. Foamed extrusion of SANTOPRENE~ is
discussed in US Patent No 4,898,760 (all of which are herein incorporated by
reference in their entirety). SANTOPRENE~ includes a co-extruded skin that is
bonded to the foamed SANTOPRENE~.
Although SANTOPRENE~ makes a satisfactory foamed weather seal, the
SANTOPRENE~ based weather-strip must be cut when forming a weather seal at a
90 degree corner of the window or door or the frame with which the window or
door
mates. A new section of SANTOPRENE~ based weather-strip must then be
positioned at the corner, positioned 90 degrees from the previous placed
weather-
strip. The SANTOPRENE~ based weather-strips although abutting each other, do
not form a continuous weather seal at the 90 degree corner. Bending the
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SANTOPRENE~ based weather-strip results in a bulge, pucker or wrinkle at the
90°
corner which then results in the door or window not sealing properly against
the
weather-strip.
SUMMARY OF THE INVENTION
The present invention includes a weather-strip construction for providing a
weather seal, the weather-strip comprising a frame member having a cover
member
for mating with the frame member when moved toward the frame member, the
weather seal being disposed between the frame member and the cover member, the
weather seal having at least one sharp corner. The weather-strip has a foamed
sealing
member extending along the perimeter of the cover or frame member and
continuously through the sharp corner without interruption and without a
substantial
bulge, wrinkle or pucker such that the foamed sealing member forms a
continuous
weather seal between the cover member and the frame member due to its
uninterrupted extension.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of the weather-trip of the present invention.
FIG. 2a is a perspective view of the weather-strip in a casement window.
FIG. 2b is a perspective view of the weather-strip in a door.
FIG. 3 is an enlarged perspective view of the circled area 3 in Figure 2.
FIG. 4 is a sectional view of another embodiment of the weather-strip of the
present invention.
FIG. 5 is a sectional view of yet another embodiment of the weather-strip of
the present invention.
FIG. 6 is a sectional view of still another embodiment of the weather-strip of
the present invention
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
The present invention includes a weather-strip generally indicated at 10 in
Figure 1. The weather-strip 10 is capable of forming a weather seal around a
sharp
corner without a bulge, pucker or wrinkle so that a cover member such as a
door or
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window will form a weather seal along its entire length when the cover member
is
moved and pressed against a frame member. The door and window constructions
contemplated are hinged doors and casement windows. By casement windows is
meant those window sashes that are either hinged or pivot from an open
position to a
closed position. Such windows may move about a vertical or horizontal axis
between
an open and a closed position. Casement windows also include "fixed windows"
that
were made as a casement window but to which the hardware to move the window
has
not been attached or has been removed and the window when installed is fixed
in a
closed position with the weather-strip providing a weather seal.
By sharp corner is meant a corner making an abrupt bend as compared to a
rounded bend. Such corners on doors and windows are typically approximately 90
degrees although other angles such as 60 degrees are also contemplated.
Generally
angles much greater than 90 degrees do not produce sharp corners while angles
less
than 90 degrees always do.
By a weather seal is meant that the door or window when in a closed position
with the frame member compressively engages the weather-strip continuously
throughout its length with no substantial gaps through which air may flow. It
is
understood that no bulge, wrinkle or pucker results at a sharp bend of the
weather-
strip in a weather seal engagement of the present invention since this would
result in
discontinuous contact. The weather seal continues through the sharp corner due
to the
continuous extension of the weather-strip without interruption as discussed
subsequently.
By bulge, pucker or wrinkle is meant that the weather-strip at the sharp
corner
rises substantially above, or creases at the sealing plane of the weather-
strip when it
runs along a straight path. The words bulge, pucker or wrinkle may be used
interchangeably herein and refer to the same phenomenon.
As illustrated in Figure 1, the weather-strip 10 of the present invention
includes a sealing member 12 and an attaching member 14. The sealing member 12
acts as a seal between the cover member (window sash 21 of the window 16 or
door
17) and the frame member 18 as illustrated in Figures 2a and 2b. The weather-
strip
10 may be mounted on the window sash 21 or on the window frame 18 as
illustrated
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in broken lines in Figure 2a. In Figure 2b, the weather-strip is illustrated
as attached
to a stop 23 of the door frame 18. The attaching member 14 attaches the
weather-strip
as discussed subsequently.
The sealing member 12 is made of an ethylene propylene dime monomer
5 (EPDM) rubber that is foamed and cured. By cured is meant that the EPDM is
crosslinked. When EPDM is foamed, a skin is formed on the outer surface of the
extrudate providing both an esthetically pleasing surface and a durable
sealing
surface. The skin is an integral part of the extrudate being formed as the
extrusion
progresses and is formed from the same polymer that is being foamed. The skin
is
10 typically a thin layer with no cells visible in the skin to the naked eye.
The skin aids
in reducing the bulge, pucker or wrinkle that might otherwise be formed at the
sharp
corner if using a foamed SANTOPRENE~ with skin. The sealing member extends
through the sharp corner continuously, that is, it is not cut and then the
ends bonded
together. In continuing without interruption through the sharp corner, without
a
substantial bulge, pucker or wrinkle, the sealing member forms a continuous
seal
through the sharp corner. A low friction coating may be applied to the skin
for
particular applications to reduce friction.
The foamed EPDM has good resistance to compression set and is resilient
(capable of returning to its original shape after having been compressed ) so
as to be
well suited for use as a weatherseal. Other components may also be mixed with
the
EPDM for various purposes but EPDM will still be the major polymeric component
of the foamed sealing member. In the spirit of this disclosure other materials
that
exhibit similar performance characteristics to EPDM foam can be substituted
for the
EPDM without discrediting the novelty of this invention.
The sealing member is foamed using standard extrusion foaming techniques.
A standard single screw extruder can be used. Extruders having a 24:1 L!D to
48:1
L/D ratio are suitable for producing the foamed EPDM sealing member of the
present
invention. The melt temperature of the extrudate should be in the range of 300
degrees Fahrenheit to 450 degrees Fahrenheit. The EPDM is foamed using a
blowing
agent. The blowing agent can either be a chemical blowing agent or water.
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A cross section of the sealing member 12 extrudate is illustrated in Figure 1.
The geometry of the cross-section of the sealing member extrudate 12
corresponds to
that of the cross-sectional profile of the lateral land at the face of the die
(not shown).
The dimensions of the foamed extrudate are enlarged when exiting the die (not
shown) and the extent of such enlargement is a function of the process
conditions, the
rate of extrusion (screw speed, rpm), and density of the extrudate formed.
Such
processing parameters are well within the ability of one skilled in the art.
As
understood various t5rpes of cross sectional profiles are possible with foamed
EfI)M.
As illustrated in Figure 1, the sealing member may also have tubular hollow
30 formed during extrusion. The tunnel 30 in some situations is useful to
increase the
softness of the sealing member when the sealing member is foamed at a higher
density. The hollow 30 compensates for the higher density foam. In one
example, the
sealing member had a
diameter of approximately 0.225 inches and the hollow 30 had a diameter of
approximately t).100 inches. The wall thickness a between the wall 31 of the
hollove
30 and the outer surface 32 of the sealing member 12 was approximately 0.0625
inches.
The wall thickness cx may v~r~~ decreasing with more dense foams while
increasing
with less dense foams, depending on a variety of factors. It should be
understood that
the hollow 30 is not necessary and the sealing member may be made without the
hollow 30 as illustrated in Figure 6.
The densit~~ of the foamed EPDM will vary dependW g on the characteristics oI
the window or door, but will range approximately from 1.0 to 30 lbs/ft3 and
typically
may range from 5 to 25 lbs/ft3.
The attaching member 14 in one embodiment is also made of EPDM but in a
solid non-foamed extrudate. The function of the attaching member 14 is to
attach the
weather-strip 10 to the cover member 16 by insertion into a kerf 22 formed in
the
cover member lb as illustrated in Figure 3. In practice the kerf 22 is a slot
cut into the
wood or in the case of a polymer-based cover member a molded c>r cut slot.
Therefore the cross sectional profile of the attaching member l4 is such that
it should
be easy to insert the attaching member 14 into the kerf 22 and once inserted
into the
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kerf 22, the attaching member 14 is difficult to remove and acts as a~z anchor
for the
weather-strip. The attaching member 14 is progressively inserted into the kerf
22a
and is bent at corner 28 and then into herf 22b. the particular sequence
employed not
being important. As illustrated in Figure l , the attaching member includes a
plurality
of barbs 24 that are positioned to engage the walls of the kerf 22 and act
against
wifhdrawal of the attaching member 14. Other types of attaching members which
have a point projecting in a direction reverse to insertion to produce
resistance from
withdrawal are within the scope of the present invention.
The attaching member 14 can be made of EPDM and in one embodiment is
made from an EPDM having a Shore A Hardness of approximately 75. EPDM
having other hardness ratings along with other types of polymers such as
polypropylene or polyethylene can be used. The material for the attaching
member 14
needs to be rigid or at least semi-rigid enough to be capable of insertion
into the kerf
22 and have sufficient integrity to resist being withdrawn from the kerf 22.
The
material also needs to be compatible with the EPDM of the sealing member in
terms
of its ability to be bonded with the sealing portion or to be co-extruded with
the
sealing portion. Bonding is typically accomplished through the use of a
suitable
adhesive or by heat weld or heat seal.
The attaching member may also have a cord or string (not shown) disposed
within , the cord or string running longitudinally through the attaching
member. The
cord or string prevents stretching of the attaching member.
The weather-strip of the present invention can also be attached to the cover
member using an adhesive or through a strip attached to the sealing member
that in
turn is adhesively attached to the cover member as illustrated in Figure 6.
The
embodiment 310
includes a sealing member 312 and an adhesive strip 314 having a backing 316
and a
layer of adhesive 318. The embodiment 310 is secured directly to the cover
member
through the use of the adhesive.
Another embodiment of the present invention is illustrated in Figure 4. The
embodiment in Figure 4 includes a sealing member 112 similar to the sealing
member
illustrated in Figure 1. The sealing member is attached to an attaching member
that
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has an "L"-shaped cross sectional profile. The attaching member also includes
barbs
124 which are positioned in a direction so that the attaching member can be
inserted
into a kerf (not shown), but resists removal of the attaching member from the
kerf
once inserted into the ker~ The attaching member 114 includes a cap portion
126 and
a leg portion 127. The leg portion extends from one side of the cap portion
thereby
forming the "L" cross sectional profile. The cap portion 126 of Figure 4 is
wider than
the cap portion illustrated in the embodiment of Figure l, therefore when the
weather-
strip 110 is bent at a sharp corner, a bulge may result. To eliminate the
bulge, the cap
portion may be cut without cutting the sealing member 112 starting at or near
a distal
end 129 and cutting to where the leg portion 127 meets the cap portion 126 or
vice
versa. In some situations, depending on the thickness and the elasticity of
the material
used for forming the attaching member 114, the cap 126 may have to be notched
such
that a portion is removed.
Another embodiment of the present invention is illustrated in Figure 5. The
embodiment 210 includes a sealing member 212 similar to the sealing members
discussed with respect to Figures 1 and 4. The attaching member 215 includes a
leg
portion 225 that extends from the cap portion 226 bent in an "L" shaped manner
such
that the distal end portion 227 is substantially parallel to the cap portion
226. It will
be appreciated that the embodiment 210 engages a kerf (not shown) that is
located on
the surface 90 degrees from the surface from which the sealing portion 212
extends.
Although the present invention has been described with reference to preferred
embodiments, workers skilled in the art will recognize that changes may be
made in
form and detail without departing from the spirit and scope of the invention.
