AU785327B2 - Spacer for insulated windows having a lengthened thermal path - Google Patents

Description

w O P/00/0011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title: Wallace H. PETERSON Wallace H. PETERSON Freehills Carter Smith Beadle 101 Collins Street Melbourne Victoria 3000 Australia SPACER FOR INSULATED WINDOWS HAVING A LENGTHENED THERMAL PATH The following statement is a full description of this invention, including the best method of performing it known to us SPACER FOR INSULATED WINDOWS HAVINC A LENGTHENED THERMAL PATH BACKGROUTND OF THE INVENTION a. Field of the Invention Thc present invention relates to spacer frame bars which are uscd to maintain separation between glass panes in insulated glass windows and other panels and, in particular, to a spacer frame bar having an upper web which is configured to create a lengthened thermal path between the glass panes without causing a significant increase in thermal gain when exposed to solar radiation.

b. Related Art 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.

Typically, the glass panes are separated by a spacer frame which lies between the glass panes and extends around their perimeter. Thc 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. Aiso, aluminum and steel exhibit good corrosion resistance and arc stable over a wide range of temperatures, and the structural integrity of these materials is not adversely affected by long-term exposure to sunlight.

The use of aluminum, steel or other mectals in a spacer frame, however, is not without its problems. A significant beat 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.

Moreover, heat transfer through the spacer may cause the edge or other area of the window which is in contact with the spacer to bc at a signficantly higher or lower temperature than the rest of the pane. In particular, where outside tempcratures are cold, this may cause the edges of the window to be relatively cool around the interior pane cooler than the interior of the building), resulting in serious condensation problems.

One partial solution to heat trnsfer through the spacer is provided by U.S. patent 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 25 still be an issue because the metal on either side of the thermal break still rapidly conducts thermal energy.

Another partial solution is provided by U.S. Patent 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 straightAline 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 also allow the desiccant material (typically, a silica gel or other material which is in granular forin 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.

Although some prior attempts have thus been made to reduce heat transfer through a spacer by forming a lengthened thermal path in one way or another, the results have been somewhat mixed. In particular, thc uppcr wcb of the spacer that part of the spacer which faces inwardly towards the intcrpanc space) has remained something of a "weak link," in that this often forms the shortest, most direct thermal path between the two panes. Typically, the upper web has been confined to a generally horizontal plane, extending perpendicular to the planes of the glass, both for aesthetic reasons and also because the upper web of the spacer must not Project above the "Sight line" of the window or else it will obstruct and reduce the available viewing area.

An additional complication relates to the fact that the upper web of the spacer is typically exposcd to fairly intense solar radiation, sunlight. Absorption of solar radiation causes thermal gain heating) in the spacer unit, with the thermal energy being transferred to the adjoining panes. This can be a serious source of thermal inefficiency, particularly in hot, sunny climates. For cxamplc, in such climates thc interiors of buildings are commonly air-conditioned, and in a large building (such as a commercial office tower) the combined thermal gain of the spacers in the numerous windows can contribute significantly to the load on the air-conditioning plant. Therefore, it is generally desirable to reduce the tendency of the spacer to absorb solar radiation, and, conversely, any configurations which are intended to increase the length of the thermal path across the upper web should not do so at the cost of added absorption of such radiation.

Accordingly, there exists a need for an improved metal spacer bar which defines elongate thermal conductive paths between glass panes, particularly across the top web of the spacer, so as to enhance the thermal efficiency of insulated windows or other panels.

Furthermore, there exists a need for such an improved spacer bar which provides such lengthened conductive paths without causing increased thermal gain of the spacer due to absorption of solar radiation. Still further, there exists a need for such a spacer bar which establishes fluid contact between the air or other gasses in the interpane space and a desiccant material within the bar, but without possibility of the desiccant escaping therefrom into the space between the panes.

4 SUMMARY OF TH-E INVENTION 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 and defining a spacer width between the side webs, the upper web of the spacer member comprising at least first and second corrugations formed in the upper web, each corrugation defining an upwardly extending ridge portion and a downwardly extending channel portion so that the corrugations form an elongate thermal energy conductive path across the upper web which is greater in length than the spacer width between the side webs, the corrugations further being oriented so that only an upper edge of each ridgc portion is exposed to solar radiation between the glass panes and the channel portions of the corrugations are substantially shaded by adjacent corrugations, so that the upper web of the spacer member forms the elongate conductive path without causing increased thermal gain of the spacer member when the window assembly is exposed to solar radiation.

In a preferred embodiment, the corrugations may comprise a plurality of parallel, longitudinally extending corrugations arranged across the width of the upper web, and the ridge and channel portions of the corrugations may be oriented in a substantially vertical direction.

25 The upper web of the spacer member may further comprise at least one spaced sequence of longitudinally oriented slits fornied through thc web in each of tile corrugations, so that the slits form a series of thermal breaks across the web. The spaced sequence of slits in each corrugation may be staggered longitudinally relative to the slits in adjacent corrugations.

30 The spaced sequences of slits may be formed in side walls of the corrugations intermediate the upper ends of the ridge portions and the lower cnds of the channel portions. Each corrugation may comprise at least two spaced sequences of slits on opposite sides of the corrugation. The slits may each comprise a first longitudinal edge portion which is displaced relative to a second edge portion by an amount which is sufficient to open an air gap bctwccn the edges of thc slit.

The spacer member may further comprise at least one insulating member which is mounted in the corrugations of the upper web. The insulating member may comprise a plurality of strips formed of insulating material, each insulating strip being mounted in the channel portion of one of the corrugations. The insulating strips may substantially fill the channel portions so that only an upper crown of each ridge portion is exposed above the insulating material. The insulating material may comprise a resilient foam material.

Each of the channel portions may comprise means for engaging and retaining the strip of insulating material therein. The means for retaining the strip may comprise an inwardly-bent tab portion of a slit formned in the wall of the channel portion, Or may comprise at least one inwardly-protruding point formied in the wall of the channel portion.

The spacer member may be formed of inner and outer halves, the halves being joined along upper and lower longitudinally extending seams. The spacer member may also be formed as a two-piece structure in which thcrc is a lower, generally "Ut' shaped channel member which incorporates the lower and side webs of the spacer member, and an upper cap member which incorporates the upper web of the spacer member, the outer edges of the cap member cooperating with the upper edges of the channel member to form connection joints by which the cap member is mounted to the channel member.

The connection joints may each comprise a generally shaped receiving channel formcd along an upper edge of the channel member, and a flange portion formed along an outer edge of thc cap member which extends downwardly therefrom into :1:22 25 locking engagement with thc channel. The receiving channel may comprise a lip portion which extends downwardly from an edge of the receiving channel to a position abovc a lower edge of the flange portion, so as to retain the flange portion against being withdrawn upwardly out of the receiving channel. The flange portion, in turn, may further comprise a lip portion which extends upwardly from the lower edge of the flangc portion so as to engage the lip portion of the receiving channel in substantially vertical abutment therewith.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing aspects and many of the attendant advantages of the invention will hecome better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: FIG. 1 is a perspective view of one embodiment of an insulated glass window constructed in accordance with the present invention; FIG. 2 is a cross-sectional, perspective view of an insulated glass panel 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; FIG. 3 is a plan, somewhat schematic view of a portion of the corrugated and slitted upper wcb of the spacer bar of FIG. 2, showing the arrangement of longitudinal slits which are formed therein for further increasing the length of conductivc paths across the upper web of the bar; FIG. 4 is cross-sectional, somewhat schematic view of the window and spacer bar of FIGS. 1-3, showing the manner in which the configuration of the top web minimizes therm al gain of the bar when exposed to solar radiation; FIG. 5 is a cross-sectional, perspective view similar to FIG. 2, showing an embodiment of spacer frame bar in which the corrugations are filled with an insulating material which further reduces thermal transmission between the inner and outer panes of the window assembly; FIG. 6 is a cross-sectional, somewhat schematic view similar to FIG. 4, showing temanner in which the insulating inserts in the channels of the corrugations serve to further reduce thermal gain of the bar when exposed to solar radiation; 30 FIG. 7 is an enlarged, cross-sectional view of a portion of the upper web of a spacer bar in accordance with an embodiment of the present invention in which the sides of the corrugations are provided with inwardly-projecting points, rather than the slits which are shown in FIGS. 2-6, showing the manner in which these engage and retain the strips of insulating material; FIG. 8 is a cross-sectional, perspective view similar to FIGS. 2 and 5, showing an embodiment of a spacer frame bar in accordance with another embodiment of the present invention, this having a two-piece construction in which the upper, corrugated web is clipped or otherwise attached along its edges to a lower, shaped channel member; FIG. 9 is a cross-sectional, perspective view similar to FIG. 8, showing another embodiment of spacer bar having a two-piece construction, this having a generally flat, slitted top web in place of the corrugated web which is shown in FIG. 8; and 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.

DETAILED DESCRIPTION a. Spacer Structure An insulated glass panel 10 in accordance with the present invention is illustrated in FIG. 1. As can he 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 thc peripheral edges of the glass panes 14. The frame is formed by segments of spacer frame bars 18a, 18b, 18d, referred to herein from time to time as simply "spacers", joined at their ends by connectors to define corners 20a, 20b, 20c, 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 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 thc opposite direction outwardly from the iriterpane space), and the terms "side", "lateral", and thc like will refer to the sides of the spacer which face towards the panes. It will be understood, of course, that thc 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 pancls 2 5 constructed of glass or similar panes, whether used for Viewing, admission of light, or other purposes.

FIG. 2 shows an exemplary one of the spacer bars of which frame 12 is constructed. As can be seen, the spacer bar 1 8a is gcnerally 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.

In thc embodiment which is illustrated in FIG. 2, the spacer bar is formed by joining first and second halves 44, 46, cach of which has a generally shaped crosssectional 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 comiposite materials, arc 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 "cliptogether" construction described below or unibody construction, are also within thc scope of the present invention.

Thc two halves 44, 46 may be j .oined in any suitable manner. In the embodiment which is illustrated, the longitudinal edges of the halves arc periodically and transversely slit to definc a series of short, transverse tabs which are alternately crimped. Thc crimped tabs are interleaved in alternating fashion to form the connection between the edges of the halves: As is shown, a first elongate scam 50 is thus formed along the uppcr 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. Patent No.

5,568,714 to Peterson, the disclosure of which is hereby incorporated by reference herein.

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 2 5 to two sets of lines. The upper contact lines are farmed substantially near the comers 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.

is shown in FIG. 2, a sealant 64, preferably an clastomcr 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.

In the embodiment of the invention which is illustratcd in FIG. 2, the lower halves of the side webs 34 and 36 arc 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.

So as to further increase thc length of the conductive path across thc bottom of the spacer bar, thc lowcr scam 52 can also be bent upwardly as shown in FIG. 2, so that the interleaved tabs assume something of an inverted configuration. Additionally, this configuration reinforces the engagement of the tabs, so as to form a very strong scam which resists separaition of the two halves of the assembly.

b. Upper Web With fuirther 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.

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 see. arranged into first and second parallel scts on cither side of the top seam. The outermost ridges 76a, 76b in each sct may conveniently be formed as continuations of the bends ~me..*which form the upper contact lines 56a, 56b, with the a material being bent back on itself so as to extcnd 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 seami may have a different form or the corrugations may be continuous across the entire upper web of the spacer.

Furthermore, cach of the corrugations 70 preferably includes a series of longitudinal ly-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 incrcase the number of slits which can be formed in the space between the two glass pancs; for example, a section of flat, planar web might he able to accommodate only onc row of slits in the same space where the corrugated web is able to accommodate two such rows.

As can bc seen with reference to FIGS. 2-3, each of the slits 80 forms a thermal break, the longitudinal edges of the slit are separated by an air gap which prevents direct communication of thcrmnal energy across the slit. Moreover, thc 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.

The slits 80 thereforc 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, thermial 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.

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 silica gel) in the spacer to dehumidify the air/gas which is trappcd in the airspacc during assembly of the window, therehy 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.

in order to permit the air pass in and out of the spacer, but at thc same time prevent the desiccant material from escaping, slits 80 are preferably formed not by punching or piercing clear through the upper web of tile 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 thermnal energy, but not so large as to allow granules of desiccant to pass thcrcthrough. 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 thc material stationary for punching or stamping.

When the slits are fanned in this manncr, the metal also breaks or "tears" back at thc ends of the slits, forming first and second transverse edges 88a, 88b (see FIG. 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 travcl in a direct, diagonal line from the end of one slit to the next.

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 FTG. 4, solar radiation passing through thc outer glass pane 14a, as indicated by arrows 98, strikes only the tops or "crowns" 100 of thc 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, bccausc 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.

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 13 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 embodimcnts the corrugations may be formed by means other than by the roll-forming or bending of shcct metal, as by casting, cutting or machining, for example.

c. Insulating Strips 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.

Since, as can be seen in FIG. 6, the strips of insulating material leavc 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 5 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.

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 of the slits 80 are bent inwardly and upwardly, so that their edges protrude into thle channels and thereby engage the lower edges of the strips 112.

FIG. 7 shows another form of geometry for rctaining the insulating material within the charnels, in which pointed projections 114, rather than tabs or slits, extend inwardly from the walls of thc channels to engage the insulating material 1 10. It will be understood that the particular retaining geometry may vary from thc examples which are shown in the figures, and may take the form of ridges, indentations, projections, constrictions, scorings or any other configuration which is suitahle for engaging and holding the insulating material. Moreovcr, the retaining geometry may vary in configuration with the type of insulating material being used, and in some embodiments may he absent altogether.

Thc insulating material I110 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 arc 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 LUV 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 arc also within the scope of the invention.

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 opencell 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 thc relatively porous upper seam Two-Piece Construction 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 shaped lower channel mnember 122 and a "clip-on" upper web member 124.

As can he seen, the overall configuration of the lower channel member 122 is somewhat similar to the lower part of the spacer which was described abovc 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 1 36a, 136b for increasing of the length of the conductive path across the bottom of the spacer.

In the embodiment which is shown in FIG. 8, however, first and second flanges arc formed inboard of the upper contact lines 132a, 132b, and these extend downwardly and inwardly and then back upwardly and inwardly to define "V" M 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.

The outer edges 1 44a, 1 44b 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 1 46a, 1 46b 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.

To assemble the spacer 120, the interior of the 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 146a, 146b positioned in vertical register with receiving channels 140a, 140b. The web member is then pressed downwardly against thc channel member so that the edge flanges are forced into the rccciving channels. As this is done, the lower, somewhat inwardly-angled edges of flanges 1 46a, 1 46b ride over the 16 lips 142a, 142b of the receiving channels, so that the sides of the channels are spread apart resiliently to accept entry of the flanges.

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 to the position shown in FIG. 8), thereby capturing thc flanges and retaining them against being withdrawn from the receiving channels I 40a., 140b. Thus, once installed, the web member 124 is more or less pcrmanently mounted to the shaped channel member 122.

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.

A particular advantage of the two-piece "snap together" construction which is shown in FIGS. 8-10 is that thc "broken" attachment points along the two edges of the spacer create discontinuities which further reduce conductive heat transfer across the upper web of the spaccr. Furthermore, the "breaks" at the edge joints pen-nit air/gasses to pass between the interpane space and the intcrior of the spacer, even in embodiments in which the upper web itself lacks any slits or other perforations.

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 the shaped lower channel member) to be formed of a less expensivc 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.

Moreover, the snap-together construction allows upper web members of different types to be interchangeably mounted on a commnon form of lower channel, thereby allowing for simplified and more economical manufacture of different models of spacer I I I I 17 bar. For examnple, 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 emibedded insulating strips similar to the embodiments which have been described above. Alternatively, other forms of upper web members can be mounted to an identical channel mnember in the same manner. For example, FTG. 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 fonmed 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 arc 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.

It is to be recognized that various alterations, modifications, and\or additions may he introduced into the constructions and arrangements of parts described above without departing from the spirit or ambit of the present invention.

Claims (2)

18- CLAIMS DEF INING TH-E INVE\JTICN ARE AS FICLLI3VS: I An spacer frame bar comprising: an elongate tubular spacer mcmber having first and second side webs for engaging first. and second glass Panes of a window assembly in spaced relationship, and upper and lower webs spanning from said first sidc web to said second sidc web and defining a spacer width between said side webs; said uppcr wcb of said 3parcr mcinbcr comprista. at least first and second corrugations formed in said upper web, each said corrugation defining an upwardly extending ridge portion and a downwardly extending channel portion, so that said corrugations form an clongate thermal energy conductive path across said upper web which is greater in length than said spacer width between said side webs; said corrugations furthier being oriented so that only an upper edge of each said ridge portion is exposed to solar radiation between said glass panes and said channel portions of said corrugations are substantially shaded from solar radiation by adjacent corrugations, so that said upper web of said spacer member forms said elongate conductive path without causing increased thermal gain of said spacer member whcn said window assembly is exposed to said solar radiation. 2. The spacer frame bar of claim 1, wherein said at least first and second corrugations comprise: A plurality of generally parallel, longitudinally extending corrugations arranged across a width of said upper web of said spacer member. 3. Trhe spacer frame bar of claim 2, wherein said ridge portions and said channel portions of said corrugations arc oriented in a substantially vertical direction. 4. The spacer frame bar of claim.2, wherein said upper edges of said ridge portions each comprise: I I I 19 a curved outer surface for scattering solar radiation which strikes said upper edge of said ridge portion. The spacer fr-ame bar of claim 2, whercin said upper web of said spacer member further comprises: at least one spaced sequence of longitudinally oriented slits formed through said upper web in each of said corrugations, so that said slits form a series of thermal breaks across said upper web of said spacer member. 6. The spacer frame bar of claim 5. whcrein said spaced sequence of slits in each corrugation is staggered longitudinally relative to said spaced sequences of slits in adjacent corrugations. 7. The spacer fr-ame bar of claim 6, wherein said spaced sequences of slits are formed in side wallIs of said corrugations intermediate said upper edges of said ridge portions and lower ends of said channel portions. 8. The spacer frame bar of claim 7, wherein each said corrugation comprises-. at least two said spaced sequences of slits formed on opposite sides of said corrugation. 9. The spacer frame bar of claim 5, wherein each slit in said spaced sequences of slits comprises: a first longitudinal edge portion which is displaced relativc to a second longitudinal cdge portion by an amount which is suflicicnt to open an air gap betwcen said edge portions of said slit. The spacer frame bar of claim 9, wherein said upper web of spacer member is formed of malleable metal shcct material. I1. The spacer franmc bar of claim 10, wherein said first edge portion of cach slit is displaced relative to said second edgc portion of said slit by an amount which is sufficient to form first and second transverse breaks in said metal material which extend generally laterally from first and second ends of said slits so as to interrupt conduction of thermal energy across said breaks. 12. The spacer frame bar of claim 11, wherein said transverse breaks at said ends of said slits extend laterally from a first sequence of slits towards a second sequence of slits. 13. The spacer frame bar of claim 2. wherein cach said upper web of said spacer member fwther comprises: at least one insulating member mounted in said corrugations in said upper web of said spacer mcmber. 14- The spacer fr-ame bar of claim 13, wherein said at least one insulating member comprises: a plurality of insulating strips formed of insulating material, each said insulating strip being mounted in said channel portion of one of said corrugations in said upper web member.

2515. The spacer frame bar of claim 14, wherein said insulating strips substantially fill said channel portions of said corrugations, so that only an upper crown of each said ridge portion is exposed above said insulating material. 16. The spacer frame bar of claim 14, wherein said insulating material comprises a resilient foam material. 17. The spacer frame bar of claim 14, wherein each said channel portion of said corrugations comprises: 21 means for engaging and retaining said strip of insulating material in said channel portion. 18. The spacer fr-ame bar of claim 17, wherein said means for retaining said strip comprises at least one inwardly-bent tab portion of a slit formed in a wall of said channel portion. 19. The spacer frame bar of claim 17, wherein said means for retaining said strip comprises at least one inwardly-protruding paint formed in a wall of said channel portion. The spacer frame bar of claim 1, wherein said spacer member is formed of inner and outer halves, said halves being joined along upper and lower longitudinally extending seams. 21. Thc spacer frame bar of claim 20, wherein said upper and lower longitudinally extending. seams each comprise interleaved rows of tabs formed along edges of said inner and outcr halves of said spacer member. *22. The. spacer frame bar of claim 2 1, wherein said interleaved rows of tabs of 25 said lower longitudinally extending seam are bent upwardly in a generally inverted "V" configuration so as to increase a length of a thermal conductive path across said lower web of said spacer member. 23. The spacer frame bar of claim 1, wherein said spacer member is formed of a lower channel member which incorporates said lower and side webs of said spacer member, and an upper cap member which incorporates said upper web of said spacer member, first and second outer edges of said cap member cooperating with first and second upper edges of said channel member to form connection joints by which said cap member is mounted to said channel member. 4 004908144 22 24. The spacer frame bar of claim 23, wherein said connection joints each comprise: a generally shaped receiving channel formed along said upper edge of said channel member; and a flange portion formed along said outer edge of said cap member and extending downwardly therefrom into engagement with said receiving channel. The spacer frame bar of claim 24, wherein each said receiving channel comprises: a lip portion which extends downwardly from an edge of said receiving channel to a position above a lower edge of said flange portion, so as to retain said flange portion against being withdrawn upwardly out of said receiving channel. 26. The spacer frame bar of claim 25, wherein each said flange portion comprises: a lip portion which extends upwardly from said lower edge of said flange portion so as to engage said lip portion of said receiving channel in substantially vertical abutment therewith. 27. A spacer frame bar substantially as hereinbefore described with reference to the accompanying drawings or incorporating any one or more of the novel features herein disclosed. 5 Dated: 7 December 2006 Freehills Patent Trade Mark Attorneys Patent Attorneys for the Applicant: W e. Wallace H. Peterson o••o oo• a. •oo a