U.S. patent application number 10/683804 was filed with the patent office on 2004-04-29 for spacer for insulated windows having a lengthened thermal path.
Invention is credited to Peterson, Wallace H..
Application Number | 20040079047 10/683804 |
Document ID | / |
Family ID | 32110989 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040079047 |
Kind Code |
A1 |
Peterson, Wallace H. |
April 29, 2004 |
Spacer for insulated windows having a lengthened thermal path
Abstract
A spacer frame bar for insulated windows or other insulated
glass panels. The bar includes an elongate tubular spacer member
having first and second side webs for engaging first and second
glass panes in spaced relationship, and upper and lower webs
spanning from the first side web to the second side web, each side
web being formed of a yieldable material and having at least one
corrugation that defines a vertically spaced gap, so that in
response to bending of the spacer frame bar about the upper web the
gaps of the corrugations collapse so as to reduce a height of the
spacer bar and thereby reduce the distance by which the lower web
is stretched at an outside radius of the bend.
Inventors: |
Peterson, Wallace H.;
(Everett, WA) |
Correspondence
Address: |
Todd N. Hathaway
199 N. Commercial St. #620
Bellingham
WA
98225
US
|
Family ID: |
32110989 |
Appl. No.: |
10/683804 |
Filed: |
October 10, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10683804 |
Oct 10, 2003 |
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10091704 |
Mar 5, 2002 |
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10091704 |
Mar 5, 2002 |
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09359341 |
Jul 21, 1999 |
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6351923 |
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09359341 |
Jul 21, 1999 |
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09222065 |
Dec 29, 1998 |
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6131364 |
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09222065 |
Dec 29, 1998 |
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08898705 |
Jul 22, 1997 |
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Current U.S.
Class: |
52/786.13 |
Current CPC
Class: |
E06B 3/66323 20130101;
E06B 2003/6639 20130101; E06B 3/66314 20130101 |
Class at
Publication: |
052/786.13 |
International
Class: |
E04C 002/54 |
Claims
What is claimed is:
1. A spacer frame bar comprising: an elongate tubular spacer member
having first and second side webs for engaging first and second
glass panes and upper and lower webs spanning from said first side
web to said second side web; each said side web being formed of a
yieldable material and comprising at least one corrugation that
defines a vertically spaced gap; so that in response to bending of
said spacer frame bar about said upper web said gaps of said
corrugations collapse so as to reduce a height of said spacer bar
and thereby reduce the distance by which said lower web is
stretched at an outside radius of the bend.
2. The spacer frame bar of claim 1, wherein each said side web
comprises an upper portion that forms a contact area for engaging a
pane of glass and a lower portion having said at least one
corrugation formed therein.
3. The spacer frame bar of claim 2, wherein said lower portion of
each side web comprises a plurality of said corrugation.
4. The spacer frame bar of claim 3, wherein each said corrugation
comprises: upper and lower wall portions that are spaced apart by
said gaps and that move into engagement so as limit collapse of
said side webs as said spacer frame bar is bent.
5. The spacer frame bar of claim 4, wherein said well portions of
said corrugation extend generally parallel to one another.
6. The spacer frame bar of claim 5, wherein said wall portions of
said corrugations extend generally parallel to said upper and lower
webs of said bar.
7. The spacer frame bar of claim 6, wherein said upper and lower
webs and said first and second side webs define a hollow interior
of said bar, and wherein said wall portions of said corrugations
limit collapse of said side webs to a predetermined amount such
that a passage remains open through said interior of said bar at
said bend.
8. The spacer frame bar of claim 1, wherein said lower web
comprises: a seam joining first and second sides of said lower
web.
9. The spacer frame bar of claim 8, wherein said seam is a lap
seam.
10. The spacer frame bar of claim 8, wherein said seam is a welded
seam.
11. The spacer frame bar of claim 1, wherein said yieldable
material is roll formed aluminum alloy.
Description
CONTINUING INFORMATION
[0001] This is a continuation-in-part application of pending patent
application Ser. No. 10/091,704, entitled "Spacer for Insulated
Windows having a Lengthened Thermal Path", which was filed Mar. 5,
2002 as a continuation application of issued U.S. Pat. No.
6,351,923, which was filed Jul. 21, 1999 as a continuation-in-part
application of issued U.S. Pat. No. 6,131,364, which was filed on
Dec. 29, 1998 as a continuation-in-part of patent application Ser.
No. 08/898,705, which was abandoned on Jul. 22, 1997.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to spacer frame bars which are
used to maintain separation between glass panes in insulated glass
windows and other panels and, more particularly, to a spacer frame
bar having folded or corrugated sides so as to permit the bar to be
bent at the corners of the spacer frame without coverstressing the
lower web of the bar.
[0004] 2. Related Art
[0005] It is well known in the art to provide a window with more
than one pane of glass separated by an airspace. Such windows are
known as insulating windows or insulated glass panels, by virtue of
the fact that the air and/or other gasses (argon, helium, nitrogen,
etc.) trapped within the space between the glass panes serves as an
insulator to reduce heat flow through the window.
[0006] Typically, the glass panes are separated by a spacer frame
which lies between the glass panes and extends around their
perimeter. The spacer frame is typically constructed of sections of
tubular material, also known as spacer frame bars, which are
usually made of a metal such as aluminum alloy, steel or stainless
steel. In addition to being commercially economical, these
materials have the strength and rigidity which are required in
order for the spacer frame serve its structural functions. Also,
aluminum and steel exhibit good corrosion resistance and are stable
over a wide range of temperatures, and the structural integrity of
these materials is not adversely affected by long-term exposure to
sunlight.
[0007] The use of aluminum, steel or other metals in a spacer
frame, however, is not without its problems. A significant heat
transfer problem may arise because an aluminum or metal spacer is a
much better heat conductor than the surrounding airspace. Because
the spacer and glass panes are contiguous, the spacer itself acts
as a conduit for energy transfer between inside and outside panes
of glass. Thus, significant energy loss may result because of the
spacer's physical contact with the glass panes.
[0008] Moreover, heat transfer through the spacer may cause the
edge or other area of the window which is in contact with the
spacer to be at a significantly higher or lower temperature than
the rest of the pane. In particular, where outside temperatures are
cold, this may cause the edges of the window to be relatively cool
around the interior pane (i.e., cooler than the interior of the
building), resulting in serious condensation problems.
[0009] One partial solution to heat transfer through the spacer is
provided by U.S. Pat. No. 5,568,714 to Peterson. The invention of
Peterson provides an elongate tubular spacer with an integral
thermal break that reduces energy flow between glass panes.
Although the thermal break impedes heat transfer through the
spacer, heat transfer impedance can still be an issue because the
metal on either side of the thermal break still rapidly conducts
thermal energy.
[0010] Another partial solution is provided by U.S. Pat. No.
5,377,473 to Narayan et al. The invention of Narayan provides a
spacer having a lower web which is generally W-shaped in
cross-section, and an upper web which is pierced by a series of
slots which are intended to eliminate straightline thermal paths
across the web and also to allow fluid contact between the air in
the interpane space and a desiccant material inside the spacer.
Unfortunately, the slots allow the desiccant material (typically, a
silica gel or other material which is in granular form so as to
maximize surface area) to escape from the spacer and into the
interpane space, where it tends to foul the inside surfaces of the
panes.
[0011] An additional problem of conventional spacer bar tubing is
its inability to form sharp (e.g., 90.degree.) bends, specifically,
the bends at the corners of a window spacer frame. As the tubing is
bent to form a corner, the outside bend of the tubing is forced to
stretch, and the sidewalls of the tubing are also both stretched
and compressed. This combination of forces frequently causes the
outside (lower) flange of the tubing to snap under tension, and
frequently cause the sidewalls to break as well, so that the tubing
and frame are ruined. Moreover, even if the tubing does not suffer
outright breakage, the stretching forces cause the outside web to
separate along any seams or joints formed therein, for example, at
the welded or crimped seam formed when manufacturing of the tubing.
This problem is severe enough with tubing having an ordinary
rectangular cross section, and would be even more pronounced in the
case of tubing having a vertically-folded lower web, such as that
which is shown in the Narayan reference.
[0012] Because of these difficulties, angled connector pieces,
known as "corner connectors," have been developed which are
inserted into ends of straight sections of tube at the corners of
the spacer frame. Although effective in their own right, the use of
corner connectors obviously means that additional pieces (the
connectors) must be used in the assembly and it also means that
sections of tubing must be cut to form the sides of the spacer
frame, which adds significantly to the time and expense of the
assembly process. In some instances the connectors also have a
tendency to inadvertently slide out of the tubing or form a bad
connection, again slowing and adding waste to the process.
[0013] Accordingly, there exists a need for an improved metal
spacer bar which defines elongate thermal conductive paths between
glass panes. Furthermore, there exists a need for such an improved
spacer bar which can be bent at a sharp angle to form corners of a
spacer frame without breaking or otherwise stressing the outer web
thereof. Still further, there exists a need for such an improved
spacer bar which is simple and economical to manufacture.
SUMMARY OF THE INVENTION
[0014] The present invention has solved the problems cited above.
Broadly, this is a spacer frame bar comprising an elongate tubular
spacer member having first and second side webs for engaging first
and second glass panes in spaced relationship, and upper and lower
webs spanning from the first side web to the second side web, each
side web being formed of a yieldable material and comprising at
least one corrugation that defines a vertically spaced gap, so that
in response to bending of the spacer frame bar about the upper web
the gaps of the corrugations collapse so as to reduce a height of
the spacer bar and thereby reduce the distance by which the lower
web is stretched at an outside radius of the bend.
[0015] Each side web may comprise an upper portion that forms a
contact area for engaging a pane of glass and a lower portion
having the said at least one corrugation formed therein. The lower
portion of each side web may comprise a plurality of the
corrugations.
[0016] Each of the corrugations may comprise upper and lower wall
portions that are spaced apart by said gaps and that move into
engagement so as limit collapse of said side webs as said spacer
frame bar is bent. The wall portions of said corrugation extend
generally parallel to one another and generally parallel to the
upper and lower webs of the bar.
[0017] The upper and lower webs and said first and second side webs
may define a hollow interior of the bar, and the wall portions of
the corrugations may limit collapse of the side webs to a
predetermined amount such that a passage remains open through the
interior of said bar at the bend.
[0018] These and other features and advantages of the present
invention will be apparent from a reading of the following detailed
description with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The foregoing aspects and many of the attendant advantages
of the invention will become better understood by reference to the
following detailed description, when taken in conjunction with the
accompanying drawings, wherein:
[0020] FIG. 1 is a perspective view of an insulated glass panel
constructed with spacer bar tubing in accordance with the present
invention;
[0021] FIG. 2 is a cross-sectional, perspective view of a portion
of the insulated glass panel of FIG. 1, showing a first embodiment
of spacer frame bar in accordance with the present invention
positioned between two glass panes, showing the corrugated and
slitted upper web thereof;
[0022] FIG.3 is a side, elevational view of the spacer frame tubing
of FIG. 2, showing the manner in which the holes in the side walls
of the tubing enable the side walls to collapse so as to avoid
overstressing the outer web of the tubing as it is bent to form a
sharp angled corner;
[0023] FIG. 4 is a front, elevational view of a spacer frame having
corners formed by bending the spacer frame tubing as shown in FIG.
3;
[0024] FIG. 5 is a an end, cross sectional view of a spacer frame
tubing of FIG. 2, showing the profile thereof in greater
detail;
[0025] FIG. 6 is an end, cross sectional view, similar to FIG. 5,
of another embodiment of spacer frame tubing in accordance with the
present invention, again showing the corrugated profiles of the
side walls thereof;
[0026] FIG. 7 is an end, cross sectional view, similar to FIGS.
5-6, of another embodiment of spacer bar tubing in accordance with
the present invention, each side wall thereof having a single hole
corrugation formed therein;
[0027] FIG. 8 is a perspective, cross sectional view, similar to
FIG. 2, showing another embodiment of spacer bar tubing in
accordance with the present invention, this having holes or
corrugations in the upper web as well as the side walls
thereof;
[0028] FIG. 9 is a perspective, cross sectional view, similar to
FIG. 8, of another embodiment of spacer bar tubing in accordance
with the present invention, this having a generally flat, slitted
top web in place of the corrugated web which is shown in FIG. 8;
and
[0029] FIG. 10 is an enlarged, cross-sectional view of the joint
formed between the upper web and lower channel in another
embodiment of the two-piece spacer construction, in which the edge
of the upper web has a small return bend for forming a locking
interfit with a corresponding lip along the edge of the channel
member.
[0030] FIG. 11 is an elevational view of a portion of a window
spacer frame constructed using the spacer bar of the present
invention, shown in the manner which the tubular bar is bent to
form a 90.degree. corner;
[0031] FIG. 12 is a first simplified cross sectional view of the
bar forming the spacer frame, taken along line 12-12 in FIG. 11,
showing the configuration of the spacer bar in the straight
sections of the frame; and
[0032] FIG. 13 is second simplified cross sectional view of the bar
of the spacer frame, taken along line 13-13 in FIG.1 1, showing the
manner in which the corrugations collapse when the spacer bar is
bent so as to reduce stretching and damage to the structure
thereof.
DETAILED DESCRIPTION
a. Spacer Structure
[0033] An insulated glass panel 10 in accordance with the present
invention is illustrated in FIG. 1. As can be seen, panel 10
includes an essentially rectangular spacer frame 12 sandwiched
between first and second panes of glass 14a, 14b, thereby defining
a hermetic airspace 16 within the space bounded by the panes and
frame. The frame 12 extends completely around the outer periphery
of the insulated glass panel 10, adjacent the peripheral edges of
the glass panes 14. The frame is formed by a spacer frame bar 18,
referred to herein from time to time as simply the "spacer" or
"spacer tubing".
[0034] For ease of understanding, the terms "upward", "upper",
"top" and so on will refer in this description and the appended
claims to that side of the spacer which faces towards the interpane
space (i.e., towards the space between the two panes; conversely,
the terms "downward", "lower", "bottom" and the like will refer to
the side of the spacer which faces in the opposite direction (i.e.,
outwardly from the interpane space), and the terms "side",
"lateral", and the like will refer to the sides of the spacer which
face towards the panes. It will be understood, of course, that the
actual physical orientation of the spacer will depend on its
location within the window or other panel. Furthermore, the term
"window", as used in this description and the appended claims,
means all panels constructed of glass or similar panes, whether
used for viewing, admission of light, or other purposes.
[0035] FIG. 2 shows the spacer tubing 18 of which frame 12 is
constructed. As can be seen, the spacer tubing is generally
rectangular in cross-section, having generally parallel upper and
lower webs 30, 32, and generally parallel side webs 34, 36. The
four webs define a hollow interior 40, which typically contains a
mass of desiccant material 42, such as silica gel, usually in
particulate form.
[0036] In the embodiment which is illustrated in FIG. 2, the spacer
bar is formed by joining first and second halves 44, 46, each of
which has a generally "C" shaped cross-sectional profile. The first
and second halves are preferably each roll formed from a continuous
piece of high strength material, such as aluminum alloy or steel,
although other materials, such as glass or composite materials, are
within the scope of the invention. Similarly, although the spacer
bar which is shown in FIG. 2 is constructed from inner and outer
halves, other forms of construction, such as the two-piece
"clip-together" construction described below or unibody
construction, are also within the scope of the present
invention.
[0037] The two halves 44, 46 may be joined in any suitable manner.
In the embodiment which is illustrated, the longitudinal edges of
the halves are periodically and transversely slit to define a
series of short, transverse tabs which are alternately crimped. The
crimped tabs are interleaved in alternating fashion to form the
connection between the edges of the halves: As is shown, a first
elongate seam 50 is thus formed along the upper web 30 of the
spacer by the overlapping intersection of the first and second
halves, and a second seam 52 is similarly formed along the lower
web 32. The seams each preferably include an insulating strip 54,
which is installed between the interleaved tabs to form an integral
thermal break between the two halves. The insulating strip 54 is
suitably formed of a non-metallic, low heat-conductive material,
such as plastic or rubber, for example, and is preferably
interwoven into the seams in the manner disclosed in U.S. Pat. No.
5,568,714 to Peterson, the disclosure of which is hereby
incorporated by reference herein.
[0038] The first and second side webs of the spacer bar preferably
contact the glass panes 14a, 14b, along integrally molded upper and
lower contact ridges 56a, 56b and 58a, 58b, such that the contact
area between the spacer bar and the glass panes is essentially
limited to two sets of lines. The upper contact lines are formed
substantially near the corners between the top and side webs of the
bar, while the lower contact lines are formed a spaced distance
below the upper contact lines, preferably substantially near the
midpoints of the side webs 34, 36. The upper and lower contact
lines protrude beyond the general plane of their respective side
webs, with curved recesses 60a, 60b being formed between each pair
of lines. While thus limiting contact between the bar and panes to
two sets of contact lines is generally preferred, it will be
understood that other configurations, such as flat side walls which
contact the glass panes, are also in the scope of the present
invention.
[0039] As is shown in FIG. 2, a sealant 64, preferably an elastomer
or mastic-like material, extends about the outer periphery of the
insulated glass panel 10 and is formed into the recesses of the
first and second halves of the spacer, as well as into other spaces
between the side webs 34, 36, and the panes 14a, 14b. The sealant
63 thus assures that the panes are hermetically bonded to the frame
12.
[0040] In the embodiment of the invention which is illustrated in
FIG. 2, the lower halves of the side webs 34 and 36 are provided
with horizontal folds 66. The folds are formed below the lower
contact lines 58a, 58b, such that these define parallel and
alternating indentations and protrusions which extend substantially
normal to the plane of the glass. The folds lengthen the thermal
migration path through the bottom and sides of the spacer, by
providing additional material through which heat must travel before
reaching the opposing pane. The folds in the side webs do not
contact the panes, and therefore define voids which are filled with
the sealant material. While providing folds in the side webs is
thus generally preferred, it will be understood that side webs
which are devoid folds are also within the scope of the
invention.
[0041] So as to further increase the length of the conductive path
across the bottom of the spacer bar, the lower seam 52 can also be
bent upwardly as shown in FIG. 2, so that the interleaved tabs
assume something of an inverted "V" configuration. Additionally,
this configuration reinforces the engagement of the tabs, so as to
form a very strong seam which resists separation of the two halves
of the assembly.
b. Upper Web
[0042] With further reference to FIG. 2, it will be seen that the
upper web 30 of the spacer bar, rather than being flat as in
conventional forms of construction, is provided with a plurality of
longitudinal, substantially parallel corrugations 70. These follow
a somewhat sinusoidal path about the generally horizontal plane of
the upper web, each corrugation defining a ridge portion 72 and a
channel portion 74.
[0043] In the embodiment which is illustrated in FIG. 2, in which
the first and second halves of the spacer are joined by
longitudinal center seams, the corrugations are arranged into first
and second parallel sets on either side of the top seam. The
outermost ridges 76a, 76b in each set may conveniently be formed as
continuations of the bends which form the upper contact lines 56a,
56b, with the a material being bent back on itself so as to extend
inwardly and downwardly towards the adjacent channel; the innermost
ridges 78a, 78b, in turn, flank the center seam 50 and flatten out
along their inner edges to form the interlocking tabs. In other
embodiments, of course, the seam may have a different form or the
corrugations may be continuous across the entire upper web of the
spacer.
[0044] Furthermore, each of the corrugations 70 preferably includes
a series of longitudinally-oriented, spaced apart slits 80. As can
be seen in FIG. 3, there are preferably at least two rows 82a, 82b
of slits in each corrugation, on opposite sides of each channel. A
particular advantage of the corrugated upper web is that the
corrugations increase the number of slits which can be formed in
the space between the two glass panes; for example, a section of
flat, planar web might be able to accommodate only one row of slits
in the same space where the corrugated web is able to accommodate
two such rows.
[0045] As can be seen with reference to FIGS. 2-3, each of the
slits 80 forms a thermal break, i.e., the longitudinal edges of the
slit are separated by an air gap which prevents direct
communication of thermal energy across the slit. Moreover, the
slits are preferable arranged so as to be staggered from one row to
the next, such that the slits in one row alternate and overlap in
spaced relationship the slits in the next row, thereby eliminating
any straight-line conductive path in the transverse direction.
[0046] The slits 80 therefore cooperate with corrugations 70 to
greatly increase the length of the conductive path across the upper
web of the spacer. As can be seen in FIG. 3, the corrugations force
the energy to follow a path which travels up and down in the
vertical plane, while at the same time the staggered slits force
the energy to travel back and forth in the horizontal plane. As a
result, thermal energy passing from one glass pane to another
follows a tortured, circuitous path as indicated by arrows 93,
through a distance which is much longer than the straight-line
distance from one glass pane to the other.
[0047] In addition to providing thermal breaks, the slits also
serve as ventilation apertures which establish fluid communication
between the inter-pane airspace 16 and the interior of the spacer.
This allows the desiccant material 42 (e.g., silica gel) in the
spacer to dehumidify the air/gas which is trapped in the airspace
during assembly of the window, thereby minimizing the possibility
of condensation forming inside the window. As is well known in the
art, air is constantly circulated within the window by changes in
barometric pressure, which cause the glass panes to act like
diaphragms which pump air in and out of the airspace 16.
[0048] In order to permit the air pass in and out of the spacer,
but at the same time prevent the desiccant material from escaping,
slits 80 are preferably formed not by punching or piercing clear
through the upper web of the spacer, but instead by shearing or
splitting the material along the edges 84, 86 of the slits and
moving this apart so as to create an air gap which is wide enough
to interrupt conduction of thermal energy, but not so large as to
allow granules of desiccant to pass therethrough. The slits can be
formed in this manner using a rotating cutter reel, which allows
the slits to be formed continuously during roll forming of the
spacer, rather than having to stop or otherwise hold the material
stationary for punching or stamping.
[0049] When the slits are formed in this manner, the metal also
breaks or "tears" back at the ends of the slits, forming first and
second transverse edges 88a, 88b (see FIG. 3). The result is
essentially a shallowly bent tab portion 90, bordered by thermal
breaks along three sides. The "tear back" edges 88a, 88b along the
sides of the tabs extend laterally towards the next row of slits,
which further increases the length of the conductivity path by not
allowing the heat to travel in a direct, diagonal line from the end
of one slit to the next.
[0050] While, as has been described above, the corrugated
configuration of the upper web provides a greatly lengthened
thermal path, it does not accomplish this at the expense of added
thermal gain when exposed to solar radiation. As is seen in FIG. 4,
solar radiation passing through the outer glass pane 14a, as
indicated by arrows 98, strikes only the tops or "crowns" 100 of
the ridge portions, the major portion of each corrugation being
shadowed by its neighbors. In other words, only the crowns 100 are
exposed to the radiation, and these represent only a very small
fraction of the total surface area of the web 30. Moreover, because
the surfaces of the crowns 100 are curved (owing to the curvature
of the bends in the metal), these will have a tendency to deflect
and scatter solar radiation rather than absorb it, even when the
sun is at its highest elevation relative to the spacer.
[0051] The advantages provided by the corrugations in the upper web
pertain regardless of whether the web also includes the slits 80.
It will therefore be understood that, while a preferred form and
arrangement of slitted web has been described above, spacers having
webs with other forms of slits or no slits at all are also within
the scope of the present invention. It will also be understood that
while the vertically aligned, evenly spaced corrugations which are
shown in the figures have numerous advantages, including
manufacturing economy, ease of installation and aesthetics, for
example, in other embodiments the corrugations may be angled in one
direction or another, may have varied spacings or heights, and so
on. Moreover, in some embodiments the corrugations may be formed by
means other than by the roll-forming or bending of sheet metal, as
by casting, cutting or machining, for example.
c. Insulating Strips
[0052] As is shown in FIG. 5, the channel portions 74 of the
corrugations can be filled with an insulating material 110, so as
to further reduce thermal gain and heat migration across the upper
web of the spacer. In the embodiment which is illustrated in FIG.
5, the insulating material is formed into a plurality of individual
strips 112 which are installed in the channels by suitable means,
such as by pressing or by extruding the material directly into the
channels, for example.
[0053] Since, as can be seen in FIG. 6, the strips of insulating
material leave only the very tops of the crowns 100 exposed, the
potential for thermal gain from absorption of solar radiation is
greatly minimized. Moreover, to further reduce thermal gain, the
crowns (or the entire top of the upper web) can be painted white,
since this color generally has the lowest thermal absorption rate,
and the insulating material itself can also be painted or formed in
a white color if desired.
[0054] The geometry of the channels is preferably configured so as
to grip the insulating material and retain it therein, since the
different thermal expansion rates of the insulating material and
metal web will otherwise tend to cause the former to buckle or
"pop" out of the channels. For example, in the embodiment which is
shown in FIG. 5 the tab portions 90 of the slits 80 are bent
inwardly and upwardly, so that their edges protrude into the
channels and thereby engage the lower edges of the strips 112.
[0055] FIG. 7 shows another form of geometry for retaining the
insulating material within the channels, in which pointed
projections 114, rather than tabs or slits, extend inwardly from
the walls of the channels to engage the insulating material 110. It
will be understood that the particular retaining geometry may vary
from the examples which are shown in the figures, and may take the
form of ridges, indentations, projections, constrictions, scorings
or any other configuration which is suitable for engaging and
holding the insulating material. Moreover, the retaining geometry
may vary in configuration with the type of insulating material
being used, and in some embodiments may be absent altogether.
[0056] The insulating material 110 itself may be of any suitable
type, with a plastic material having good insulating qualities
being eminently suitable for this purpose. Resilient, foamed
plastic materials are particularly suitable for use as the
insulating material, in that the cellular structure allows for a
comparatively large degree of compression/expansion in order to
accommodate the different expansion rates. Suitable examples of
insulating materials include polyurethane foam, which is generally
UV resistant, highly stable, and acid resistant. Polyethylene foam
may also be used, which has the advantage of relative economy,
although this should generally be provided with a "skin" on the
exposed side to minimize deterioration. Moreover, the insulating
material may contain a fiber material for enhanced stability and
durability. Other suitable insulating materials will occur to those
skilled in the art, and are also within the scope of the
invention.
[0057] In some embodiments the insulating material may be formed as
a continuous "cap" which fills and spans two or more channels,
although in such instances the different expansion rates of the
materials may become an even more significant factor, tending to
cause the insulation to separate from the web. Also, in those
embodiments where it is desired to maintain fluid communication
between the inter-pane airspace and the interior of the spacer via
slits in the channels, the insulating material may be formed of an
open-cell foam material which is capable of "breathing"; in other
embodiments, where the slits are absent or are blocked by the
insulating material, the air flow can be maintained through the
relatively porous upper seam 50.
d. Two-Piece Construction
[0058] FIG. 8 shows a tubular spacer bar 120 in accordance with the
present invention, having a construction which differs from that
described above in that this is a two-piece structure with a
somewhat "U" shaped lower channel member 122 and a "clip-on" upper
web member 124.
[0059] As can be seen, the overall configuration of the lower
channel member 122 is somewhat similar to the lower part of the
spacer which was described above with reference to FIG. 2, in that
this has a bottom web 126 and first and second side webs 128, 130.
The side webs also preferably include upper and lower contact lines
132a, 132b and 134a, 134b, as well as horizontally extending folds
136a, 136b for increasing of the length of the conductive path
across the bottom of the spacer.
[0060] In the embodiment which is shown in FIG. 8, however, first
and second flanges are formed inboard of the upper contact lines
132a, 132b, and these extend downwardly and inwardly and then back
upwardly and inwardly to define "V" shape receiving channels 140a
and 140b. Furthermore, the terminal edges of the flanges are
provided with reverse bends so as to form a small locking lips
142a, 142b along the inward edges of the receiving channels.
[0061] The outer edges 144a, 144b of the upper web member 124, in
turn, are bent downwardly and inwardly so as to form first and
second downwardly projecting locing flanges 146a, 146b. As can be
seen in FIG. 8, the flanges 146a, 14b are configured to extend
roughly parallel to the sheet metal which forms the outer walls of
the receiving channels 140a, 140b, and extend downwardly from the
top web by a distance which is roughly equal to the depth of the
receiving channels.
[0062] To assemble the spacer 120, the interior of the "U" shaped
lower channel member 122 is filled with the desired amount of
desiccant material 148, and the upper web member 124 is placed
across the top opening of the channel member with the downwardly
projecting edge flanges 14a, 146b positioned in vertical register
with receiving channels 140a, 140b. The web member is then pressed
downwardly against the channel member so that the edge flanges are
forced into the receiving channels. As this is done, the lower,
somewhat inwardly-angled edges of flanges 146a, 146b ride over the
lips 142a, 142b of the receiving channels, so that the sides of the
channels are spread apart resiliently to accept entry of the
flanges.
[0063] After the lower edges of the flanges 146a, 146b have been
forced downwardly past the edges of lips 142a, 142b, the flanges
and the sides of the receiving channels spring back to their
original configurations, so that the locking lips move inwardly to
a position above the lower edges of the flanges (i.e., to the
position shown in FIG. 8), thereby capturing the flanges and
retaining them against being withdrawn from the receiving channels
140a, 140b. Thus, once installed, the web member 124 is more or
less permanently mounted to the "U" shaped channel member 122.
[0064] As is shown in FIG. 10, in some embodiments the lower edges
of flanges 146a, 146b may also be provided with reverse bends,
which form inwardly and upwardly projecting secondary locking lips
150. Thus, as the edge flanges are pressed home in the receiving
channels, the primary locking lips 142 spring or "snap" back so as
to move into abutting opposition with the secondary locking lips
150, providing very strong resistance against separation of the web
and channel members once mated.
[0065] A particular advantage of the two-piece "snap together"
construction which is shown in FIGS. 8-10 is that the "broken"
attachment points along the two edges of the spacer create
discontinuities which further reduce conductive heat transfer
across the upper web of the spacer. Furthermore, the "breaks" at
the edge joints permit air/gasses to pass between the interpane
space and the interior of the spacer, even in embodiments in which
the upper web itself lacks any slits or other perforations.
[0066] Still further, this arrangement permits the upper web to be
formed of a separate material, such as stainless steel, which
exhibits a lower rate of thermal heat transmission than most metals
but which is also more costly, while allowing the remainder of the
assembly (i.e., the "U" shaped lower channel member) to be formed
of a less expensive material such as ordinary steel or aluminum.
Similarly, the separate upper web member can be painted, coated or
otherwise treated for reduced thermal gain or other enhanced
characteristics, without having to treat the entire assembly.
[0067] Moreover, the snap-together construction allows upper web
members of different types to be interchangeably mounted on a
common form of lower channel, thereby allowing for simplified and
more economical manufacture of different models of spacer bar. For
example, as can be seen in FIG. 8, the upper web member 124 may be
formed with a series of parallel corrugations 70, with or without
embedded insulating strips 90, similar to the embodiments which
have been described above. Alternatively, other forms of upper web
members can be mounted to an identical channel member in the same
manner. For example, FIG. 9 shows a spacer 120' which the upper web
member 124', rather than being corrugated, is a generally planar
member having several rows of staggered slits 152. Although lacking
the corrugations, the slits 152 are formed in essentially the same
manner as described above (except that the tab portions 154 are
bent downwardly rather than upwardly), so that the longitudinal
edges of each slit are separated by a narrow air gap 156. Also, as
was described above, first and second breaks/tears 158a, 158b
extend laterally from the ends of each slit towards the next row of
slits, so that thermal energy must follow an elongate, circuitous
path in order to travel from one glass pane to the other, as
indicated by arrow 160.
e. Corner Bending
[0068] As noted above, a consistent problem with prior forms of
spacer bars has been the tendency to crack or separate at the seams
when bent to form a corner. In general, this caused by aluminum or
other material being pulled or stretched through an excessive
distance along the outer radius of the corner as the bend is being
formed, which is due in turn to the height of the spacer tubing
(i.e., the distance between the walls that are facing towards and
away from the interpane space). However, it will be understood that
the spacer bar must have some degree of height at the corners, or
else it will be an insufficient sidewall areas for engaging and
forming a seal with the glass panes. The present invention
overcomes this problem.
[0069] As can be seen in FIG. 11 the tubular spacer frame bar 200
of the present invention is bent to form a corner of the spacer
frame by applying pressure in the direction indicated by arrow 202
while bending the two legs 204a and 204b to a right angle or other
angular orientation. This can be done using any of variety of
conventional bending tools that are available and are well-known to
those skilled in the art.
[0070] Unlike conventional spacer frame tubing, the corrugations
206 in the side webs 208a, 208b collapse as the spacer frame bar is
bent, reducing the height between the upper and lower webs 210,
212. As a result, the distance through which the material of the
bar is stretched at the outside radius 214 of the corner is reduced
sufficiently that cracking of the material and separation of the
seams is avoided.
[0071] FIG. 12 presents a cross-sectional view of the spacer frame
bar 200, which is simplified somewhat in that the bar is shown with
a flat upper web 210. It will be understood that the upper web be
flat as shown, or may have corrugations and/or seams as shown in
FIGS. 2 and 8, or may have any other suitable configuration;
moreover, it will be understood that the upper web will in most
embodiments be provided with perforations, slits or other openings
for passage of moisture/air to the dessicant material which is
enclosed therein. Similarily, the lower web 212 is shown with an
overlapping center seam 216, but will be understood that the lower
web may have any suitable configuration; the reduced stretching of
the lower web which is provided by the present invention is
particularly advantageous for use with spacer frame bar having a
welded (e.g., laser welded) seam in the lower web, since welded
seams are particularly susceptible to separation when
over-stretched.
[0072] The two side webs 208a, 208b, in turn, are substantially
similar to those as shown above, and have upper portions that form
contact areas 218a, 218b having concave, longitudinally extending
recesses 220a, 220b bordered by upper and lower contact ridges
222a, 222b and 224a, 224b. The lower portions of the side webs, in
turn, include the corrugated areas 206a, 206b. In the illustrated
embodiment, each corrugated area includes two longitudinally
extending channels 226a, 226b and 228a, 228b, alternating with
ridges 230a, 230b and 232a, 232b. This provides the desired degree
of compression and is easily roll-formed, however, it will be
understood that a lesser or greater number of channels and grooves
may be employed in some embodiments; moreover, in addition to
providing the collapsing action the corrugated areas increase the
length of the thermal path between the lower and upper webs of the
spacer bar, and their number and configuration may be varied on the
basis of this factor as well.
[0073] As can be seen, each of the channels/ridges of the
corrugated areas have generally parallel upper and lower walls 234
so as to define a series of spaced, vertical gaps 236. Moreover,
walls 234 are disposed in parallel, face-to-face relationship on
opposite sides of each gap. As will be described in greater detail
below, the gaps from the collapsible areas that allow the height of
the side webs to collapse as the tubing is bent, and in cooperation
with the walls 234 control the direction and extent of the
deformation.
[0074] FIG. 12 shows the tubular spacer bar in its initial
configuration prior to bending, having its full height "h1". FIG.
13, in turn, shows the spacer bar in its collapsed configuration in
the area where it has been bent from the corner of the spacer
frame. As can be seen, the outwardly directed pressure at the
corner (see arrow 202) and the action of bending the two legs 204a,
204b towards one another cooperate to force the upper and lower
webs of the tubular bar towards one another, as indicated by arrow
240a, 240b. In response, the gaps 236 formed by the channels and
ridges of the corrugations collapse and disappear, until the
opposing wall portions 234 move into abutment with one another.
This results in a reduced height "h2" at the apex of the bend. As a
result, the metal of the lower web 212 is stretched through a
reduced distance (as opposed to bending a bar having a constant
height), thereby avoiding cracking of the material and at the same
time preserving the integrity of the seam 216.
[0075] The manner in which the walls 234 move into abutment as the
gaps close maintains the amount of collapse and deformation within
predetermined limits. Moreover, the configuration of the wall
portions 234, extending generally parallel to the upper and lower
webs 210, 212, helps ensure that the corrugations collapse evenly
without buckling to one side or the other. As a result, distortion
of the bar's profile is kept within acceptable limits so that the
ability to form a seal with the panes is not compromised. For an
example, as can be seen in FIG. 13, the contact areas 218a, 218b
remain substantially enact and the contact ridges 220a, 220b and
224a, 224b are not creased or peaked outside of the plane of panes;
at the same time the outer edges of the ridges 230a, 230b and 232a,
232b remain spaced inwardly by distance "d" similar to their
original configuration so as to avoid creating additional contact
points against the glass. Also, a hollow passage 242 is maintained
through the interior of the bar, between the upper portions of the
two side webs; this facilities filling the interior of the tubing
with dessicant after the bar has been bent, if desired.
[0076] The configuration of the corrugations of the preferred
embodiment which is illustrated therefore provides several
significant advantages. It will be understood, however, that in
some embodiments corrugations having somewhat different
configurations may be employed. However, in some embodiments the
tubing may be configured to collapse more completely than shown in
FIG. 13.
[0077] It is to be recognized that various alterations,
modifications, and/or additions may be introduced into the
constructions and arrangements of parts described above without
departing from the spirit or ambit of the present invention.
* * * * *