Patent Publication Number: US-2003226332-A1

Title: Methods and devices for simultaneous application of end sealant and sash sealant

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to multiple-pane insulating glass units. More particularly, the invention relates to the application of end sealant and sash sealant to insulating glass units.  
       BACKGROUND OF THE INVENTION  
       [0002] In most industrialized countries, windows touch people&#39;s lives everyday. Wherever people work and live there are windows. Windows allow the occupants of a building to view the outside world while allowing sun light to enter the interior of the building. Sunlight is a natural antidepressant and helps the human body produce vitamin D. Thus, a certain amount of sunshine is essential to mental and physical well being.  
       [0003] Human beings have a relatively narrow temperature range in which they are comfortable. Unfortunately, infra red (IR) energy from the sun entering a room through a window can quickly raise the temperature to an uncomfortable level. Many windows include low emissivity coatings which have been developed to prevent heat spikes within a room by reflecting a large portion of incident infra red energy.  
       [0004] In northern climates significant energy may be lost through windows during the winter when a building is being heated. With the rising cost of energy, efforts have been made to provide homes and other buildings with insulation which will more efficiently prevent the loss of heat to the outside. Modern buildings often include insulating glass units. Insulating glass units have been developed to reduce the amount of heat lost through windows. There are basically three types of insulating glass units commercially available today. These three types are often referred to as single glazing, double glazing, and triple glazing. Double glazed insulating glass units are the most common. These insulating glass units include a space sealed between two panes of glass. This sealed space provides insulation, the insulating effect may be enhanced by filing the space with an insulative gas such as argon, or krypton. Compared with a single pane, a double glazed insulating glass unit can cut heat loss through a window nearly in half.  
       [0005] Many office buildings include insulating glass units having a mirror-like coating. This coating cuts down on glare and allows officer workers to work efficiently even while facing the window. This type of insulating glass unit is sometimes referred to as architectural glass. Different colors of mirrored coating can be manufactured to provide a desired architectural appearance. Examples of colors include gold, green, silver and blue.  
       SUMMARY OF THE INVENTION  
       [0006] The present invention relates to multiple-pane insulating glass units. More particularly, the invention relates to the application of end sealant and sash sealant to insulating glass units. The present invention provides apparatus&#39; and methods for applying adhesive to the end seals and/or the side glass surface of an insulating glass (IG) window unit to be mounted in a frame or sash.  
       [0007] An insulating glass unit generally includes one or more parallel-opposed panes defining, with said panes, a sealed gas space having a spacer frame in between. The spacer frame has a first pair of seals between each side of the spacer frame and the opposing pane face and a second seal or pair of seals extending between the panes outside the outer peripheral face of the spacer frame. When the insulating glass units are to be mounted to the frame/sash, a bead of adhesive may be placed along the perimeter of the glass surface that will be mounted against the frame/sash. An apparatus and method of using the apparatus is provided by which adhesive is applied to the end regions of the insulating glass unit with one or more nozzles while a separate side arm extends from the device and alongside the insulating glass unit having a nozzle that delivers adhesive bead to the side of the pane to be adhered to the frame or sash.  
       [0008] One method of fabricating a window assembly in accordance with the present invention includes the step of positioning an applicator proximate the first edge of a first pane of an insulating glass unit. A first deposit may be applied to an inside face of the first pane by the applicator, and a second deposit may be applied to an outside face of the first pane. In an advantageous embodiment, the first deposit and the second deposit are applied substantially simultaneously.  
       [0009] In certain implementations, a method in accordance with the present invention may further include the steps of providing a window sash, and bringing together the outside face of the first pane, and the window sash so that the insulating glass unit is bonded to the window sash by the second deposit. In other implementations, a method in accordance with the present invention may further including the step of simultaneously applying a third deposit to an inside face of a second pane of the insulating glass unit. In yet another implementation, a method in accordance with the present invention may include the step of simultaneously applying a fourth deposit to an outside face of the second pane.  
       [0010] In some implementations in accordance with the present invention, the first deposit and the second deposit comprise the same material. For example, the first deposit and the second deposit may both comprise a sealant material (e.g., silicone sealant). In other implementations, the first deposit and the second deposit may comprise different materials.  
       [0011] In an advantageous implementation, a method in accordance with the present invention may include the step of urging the applicator toward the spacer of the insulating glass unit with a preselected force. In a particularly advantageous implementation, the preselected force may be chosen to yield a desired thickness of deposit.  
       [0012] In some implementations of the present invention, the preselected force may be provided by a biasing mechanism. In certain implementations, the biasing mechanism may include an air cylinder coupled to a slide. When this is the case, the step of urging the applicator toward the spacer of the insulating glass unit with a preselected force may include the step of maintaining a preselected pressure within a chamber of the air cylinder.  
       [0013] A method of in accordance with the present invention may include the step of moving the applicator relative to the insulating glass unit. In some implementations, a method in accordance with the present invention, the step of moving the applicator relative to the insulating glass unit may include the step of moving the applicator along a first axis that is generally parallel to the first edge of the first pane. In other implementations, a method in accordance with the present invention, the step of moving the applicator relative to the insulating glass unit may include the steps of moving the applicator along a first axis and moving the applicator along a second axis, the second axis being disposed at about a 90 degree angle relative to the first axis. The step of rotating the applicator by an angle of rotation may be advantageously interposed between the step of moving the applicator along the first axis and the step of moving the applicator along the second axis. In a particularly advantageous implementation, the angle of rotation may be about a 90 degree angle. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0014]FIG. 1 is a perspective view of an insulating glass unit;  
     [0015]FIG. 2 is a sectional view of an end portion of an insulating glass unit following application of first and second seals;  
     [0016]FIG. 3 is a sectional view of an end portion of an insulating glass unit following application of the first seal, but prior to application of the second seal;  
     [0017]FIG. 4 is a sectional view of an insulating glass unit following application of first and second seals and sash glazing;  
     [0018]FIG. 5 is a sectional view of an apparatus of the invention, application of the second seal and sash glazing is depicted;  
     [0019]FIG. 6 is a sectional view of another apparatus of the invention, application of the second seal and sash glazing is depicted; and  
     [0020]FIG. 7 is a sectional view of still another apparatus of the invention, application of the second seal and sash glazing is depicted.  
     [0021]FIG. 8 is a block diagram of a sealant application system in accordance with an exemplary embodiment of the present invention.  
     [0022]FIG. 9 is a perspective view of an illustrative assembly including applicator of FIG. 8 and an insulating glass unit.  
     [0023]FIG. 10 is an additional perspective view of assembly of FIG. 9.  
     [0024]FIG. 11 is block diagram of a sealant application system in accordance with an additional exemplary embodiment of the present invention.  
     [0025]FIG. 12 is a perspective view of applicator of sealant application system of FIG. 11.  
     [0026]FIG. 13 is a plan view of an illustrative assembly including applicator and biasing mechanism of FIG. 11.  
     [0027]FIG. 14 is a perspective view of an additional embodiment of an applicator in accordance with the present invention.  
     [0028]FIG. 15 is a plan view of an assembly including the applicator of FIG. 14.  
     [0029]FIG. 16 is a perspective view of an additional embodiment of an applicator in accordance with the present invention.  
     [0030]FIG. 17 is a plan view of an illustrative assembly including applicator of FIG. 16 and an insulating glass unit.  
     [0031]FIG. 18 is a plan view of an additional illustrative assembly including an insulating glass unit and an applicator in accordance with an additional embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION  
     [0032] In the following detailed description of preferred embodiments, reference is made to the accompanying drawings, which form a part of the detailed description, and which illustrate specific embodiments of the present invention. It is to be understood that other embodiments can be utilized and that changes to structure and process can be made without departing from the scope of the invention.  
     [0033]FIG. 1 is a perspective view of an insulating glass unit in accordance with the present invention. An insulating glass unit typically comprises two or more panes of glass held in a spaced-apart relationship by a spacer. The inner peripheral surfaces of the panes  10 ,  10 ′ are joined by a spacer  101  to define a sealable interpane space (or “gas space”)  115 . This gas space can be provided with an insulative gas fill to enhance the insulative properties of the unit. Alternatively, the gas space may simply contain air or a vacuum.  
     [0034] Typically, the spacer  101  is formed of sections of metal or plastic tubing. This tubing can be provided in a variety of cross sectional configurations. The spacer typically includes two generally-opposed lateral surfaces, which are adapted to be bonded to inner peripheral surfaces of the spaced-apart panes. Particularly advantageous spacer designs are provided in U.S. Pat. Nos. 5,439,716, 5,377,473, 5,679,419, 5,705,010, and 5,714,214, the entire teachings of each of which are incorporated herein by reference.  
     [0035] An insulating glass unit typically includes a primary or “first” seal and a secondary or “second” seal. This is best seen in FIG. 2, wherein the first seal is designated by the reference numeral  103 , and the second seal is designated by the reference numeral  105 . The first seal may be formed of a non-setting extrudable thermoplastic material that is largely impermeable to moisture vapor and gases (e.g., air, and any insulative gas fill). The first seal  103  preferably comprises of a butyl sealant (e.g., polyisobutylene). As illustrated in FIG. 2, the first seal  103  is typically applied between the lateral surfaces of the spacer  101  and the confronting inner surfaces of the panes. This seal  103  provides resistance to the permeation of air and moisture into the gas space  115 . Likewise, when the gas space  115  is filled with insulative gas, the first seal  103  acts to contain the insulative gas within the gas space  115 . During assembly of the insulating glass unit, the first seal  103  is preferably applied prior to application of the second seal  105 . Thus, the first seal  103  also facilitates assembly of the insulating glass unit by securing the spacer  101  in position while the second seal  105  is applied and cured.  
     [0036] The second seal may be formed of any material having suitable adhesive properties. For example, this seal may comprise silicone, polysulfide, polyurethane, or any other material that forms a bond with the spacer and panes. In the embodiment of FIGS. 2 and 3, the second seal  105  is deposited into a peripheral channel  215  (illustrated in FIG. 3) formed at the edge of the insulating glass unit. This peripheral channel  215  is bounded by the outer face  102  of the spacer  101  together with the peripheral inner surfaces  114 ,  114 ′ of the panes  10 ,  10 ′. Thus, the spacer  101 , together with the first  103  and second  105  seals, isolates the atmosphere in the gas space  115  from the ambient environment.  
     [0037] Preferably, a bead of sealant is also applied along the outer peripheral surface of at least one of the panes of the insulating glass unit before the unit is assembled into a sash or frame. This bead of sealant may be referred to as the “sash glazing” or “sash bead.” As is best seen in FIG. 4, the sash bead  22  is provided to seal the insulating glass unit  8  to the sash or frame  20 . Thus, the material used for the sash bead  22  is preferably one that will form a bond between the insulating glass unit  8  and the sash or frame  20 .  
     [0038] The sash bead  22  and second seal  105  may be applied in separate steps. This is undesirable for a number of reasons. For example, the extra time needed to carry out separate sealant applications makes such a process unnecessarily inefficient. It also increases the risk that insulating glass units will be damaged. For example, it is preferable to minimize the number of processing steps that are performed on an insulating glass unit to minimize the risk of damage. This risk is particularly acute given the breakable nature of conventional glass and the likelihood that at least one of the panes of each insulating glass unit will be provided with a thin film coating  20  (e.g., a solar control film  40 ), which may be especially vulnerable to being scratched.  
     [0039] Thus, the more processing steps that are performed on an insulating glass unit, the greater the risk the insulating glass unit will be damaged by contact with sealant applicators or other machinery on the assembly line. Moreover, extra machinery is typically required to carry out separate applications of end seal  105  and sash bead  22 . Other inefficiencies include the need to monitor multiple application devices or a single device during multiple applications.  
     [0040] In a preferred embodiment, panes  10 ,  10 ′ comprise glass. However, other transparent or translucent materials can also be used. Examples of materials which may be suitable in some applications include acrylic thermoplastic and polycarbonate. Moreover, the panes of an insulating glass unit can be formed of opaque materials in applications where it is not necessary to see through the panes.  
     [0041] As noted above, the panes  10 ,  10 ′ are held in a spaced-apart relationship by a spacer  101 . In more detail, the spacer  101  has two generally-opposed lateral surfaces that are bonded to inner, peripheral surfaces of the panes  10 ,  10 ′. Thus, the confronting inner surfaces  14 ,  14 ′ of the panes  10 ,  10 ′ define, together with spacer  101 , a sealed gas space (or “interpane space”)  115 . As noted above, the gas space  115  of an insulating glass unit  8  can be filled with an insulative gas atmosphere. Typically, an inert gas, such as argon, is used. These inert gas fills can be advantageously provided to increase the insulating capability of the resulting units, as compared to units that contain air. U.S. Pat. Nos. 5,957,169 and 6,158,483, issued to Trpkovski, teach particularly valuable methods and apparatuses for filling insulating glass units with insulative gas. The entire contents of each of these patents are incorporated herein by reference.  
     [0042] As is perhaps best seen in FIG. 3, the spacer  101  is bonded to the panes  10 ,  10 ′ by the first seal  103 . As noted above, the first seal  103  is preferably formed of two beads of butyl sealant, such as polyisobutylene. It is noted that the spacer  101  does not extend all the way to the edges  10 E of the panes  10 ,  10 ′. Rather, a small distance is left between the outer face  102  of the spacer  101  and the edges  10 E of the panes  10 ,  10 ′. Thus, there is formed an end channel  215  bounded by the outer face  102  of the spacer  101  and the inner, peripheral surfaces  114 ,  114 ′ of the panes  10 ,  10 ′. This end channel  215  is adapted to receive the second seal  105 , as discussed below.  
     [0043] As noted above, a bead of sealant is also preferably applied to the outer peripheral surface of at least one of the panes of an insulating glass unit. This sealant bead is sometimes referred to as the “sash bead” or “sash glazing”. As shown in to FIG. 4, the sash bead  22  is adapted to seal the insulating glass unit  8  to a sash  20 , frame, or any other structure serving a similar purpose. Thus, when the insulating glass unit  8  is to be mounted-to the sash  20 , the insulating glass unit  8  is pressed against a peripheral surface  24  of the sash  22 , thereby adhering the sash bead  22  to this surface  24  of the sash  20 . The present invention includes methods and apparatus for applying both the sash bead  22  and the second seal  105  in a single operation.  
     [0044]FIG. 5 illustrates an applicator  90  in accordance with an exemplary embodiment of the present invention. The illustrated applicator  90  comprises an applicator body including an end block  92 , two end nozzles  98 , a side block  91 , and a side nozzle  95 . The applicator  90  is operably connected to at least one sealant source (not shown). In the embodiment of FIG. 5, the end block  92  is provided with an end channel  94  that receives delivery of sealant from a single sealant source (not shown). The end channel  94  can simply be an elongated bore extending through the end block  92 .  
     [0045] The applicator  90  can alternatively be operably connected to two separate sealant sources, which are adapted to deliver sealant respectively to the end channel  94  and side channel  93 . For example, this would be preferable in cases where the end seal  105  and the sash bead  22  are formed of different materials. In the embodiment of FIG. 5, however, a single sealant source is adapted to pump sealant into the applicator  90 . For example, an outlet hose (not shown) of the sealant source (not shown) can be secured to the inlet orifice  88  of the end channel  94 . In such a case, the inlet orifice  88  can be provided with interior threading that is adapted to be matingly engaged with exterior threading provided on the outlet hose of the sealant source.  
     [0046] The sealant source can be adapted to generate sealant flow through the applicator using any desired pump system. For example, it may be preferable to utilize gear pumps, piston pumps, or some other type of positive displacement pump. In some cases, a centrifugal pump may be suitable. However, the viscosity of the sealant flowing through the applicator  90  may be too great to employ a centrifugal pump, depending upon the particular sealant used. For example, the viscosity of conventional silicone sealants typically ranges from 1 cPs to several thousand cPs. Thus, it is believed to be preferable to employ a positive displacement pump when applying most conventional silicones. For example, conventional internal or external gear pumps would likely be suitable, as would lobe or vane pumps.  
     [0047] With continued reference to FIG. 5, as the sealant source (not shown) pumps sealant into the inlet orifice  86 , the sealant is forced through the inlet portion  89  of the end channel  94 .  
     [0048] The end channel  94  includes an intersection point, at which point the side channel  93  branches off from the end channel  94 . Thus, as the pumped sealant reaches this intersection point, some of the sealant is forced into the side channel  93 , while the rest of the sealant is forced further into the end channel  94 . Accordingly, it can be seen that the sealant source drives two separate flows of sealant through the applicator  90 .  
     [0049] A first flow of sealant is pumped through the end channel  94  and toward the sealant manifold  96 . The end channel  94  has an outlet orifice  87  that opens into the sealant manifold  96 . Thus, as the first flow of sealant reaches the outlet orifice  87  of the end channel  94 , it is forced into the sealant manifold  96 . In the embodiment of FIG. 5, the sealant manifold  96  has two outlets leading respectively to first and second end nozzles  98 .  
     [0050] As is best seen in FIG. 5, the end nozzles  98  are adapted to deliver sealant into the peripheral channel or channels  215  of an insulating glass unit. Thus, the outlets of the two end nozzles  98  are advantageously separated by a lesser distance than are the peripheral inner surfaces  114 ,  114 ′ of the panes  10 ,  10 ′. This allows both end nozzles  98  to be readily positioned in the peripheral channel or channels  215  of the insulating glass unit  8 . With the nozzles  98  thus positioned, the flow of sealant from the end nozzles  98  fills the peripheral channels  215  of the insulating glass unit  8 , thereby depositing the second seal  215 . It is noted that the first seal  103  can, in some instances, be omitted. For example, FIG. 5 illustrates an insulating glass unit  8  wherein the first seal is absent. Thus, it is to be understood that the present applicator  90  can simply be used to deposit an end seal  105 , whether or not such end seal  105  is truly the “second seal.” 
     [0051] The configuration of the spacer  101  shown in FIG. 5 is Such that two peripheral channels  215  are defined at the edge of the insulating glass unit  8 . Thus, the outlets of the end nozzles  98  are advantageously aligned respectively with these two peripheral channels  215 . This allows sealant to be deposited directly into both peripheral channels  215  and minimizes the amount of excess sealant that is left on the edge of the insulating glass unit  8 .  
     [0052] The applicator  90  can also be used to deliver sealant to an insulating glass unit that has a single peripheral channel  215 . This is perhaps best understood with reference to FIG. 6, wherein the configuration of the illustrated spacer  101  is such that a single peripheral channel  215  is defined. As noted above, the outlets of the end nozzles  98  are advantageously separated by a lesser distance than are the inner, peripheral surfaces of the panes  10 . When depositing sealant into a single peripheral channel  215 , the end nozzles  98  need not be spaced-apart. In fact, the applicator  90  can alternatively be provided with a single end nozzle  98 , if so desired. For example, FIG. 7 illustrates an embodiment wherein the applicator  90  is provided with only one end nozzle  98 . In an embodiment of this nature, the sealant manifold  96  can be omitted, if so desired, and the single end nozzle  98  can simply be formed as an extension of the end channel  94 .  
     [0053] As noted above, a second flow of sealant is pumped through the side channel  93  and toward the side nozzle  95 . Thus, sealant is forced through the side channel  93  until reaching the side nozzle  95 , whereupon the flow of sealant is forced through this nozzle  95 . With reference to FIG. 5, it can be seen that the outlet of the side nozzle  95  is adapted to apply a bead  22  of sealant to a peripheral outer surface of one of the panes of an insulating glass unit.  
     [0054] In operation, the insulating glass unit  8  can be held stationary during the application process as the applicator  90  is moved into engagement with, and around the perimeter of, the insulating glass unit  8 . Alternatively, the applicator  90  can be held stationary while the insulating glass unit  8  is manipulated so as to translate the full perimeter of the insulating glass unit past the applicator  90 .  
     [0055] Upon proper placement of the end nozzle or nozzles  98  inside the peripheral channel or channels  215 , the pumping system of the sealant source is operated to force sealant through the applicator. As noted above, this generates two sealant flows through the applicator  90 , one through the end channel  92  and another through the side channel  91 . The sealant flowing through the end channel  92  is applied from the end nozzle or nozzles  98  into the peripheral channel or channels  215  of the insulating glass unit  8 . Thus, the end seal  105  is deposited. At the same time, the sealant flowing through the side channel  93  is applied from the side nozzle  95  onto the outer peripheral surface of one of the panes of the insulating glass unit. Preferably, the flow of sealant from the side nozzle  95  is slowed or temporarily stopped as the applicator  95  reaches a corner of the insulating glass unit  8 , as the end nozzle or nozzles  98  must travel the corner distance while the side nozzle  95  effectively rotates in place. As will be obvious to those skilled in the present art, this can be accomplished through conventional use of valves (not shown) within the applicator  90 .  
     [0056]FIG. 8 is a block diagram of a sealant application system  200  in accordance with an exemplary embodiment of the present invention. Sealant application system  200  includes an applicator  202  that is coupled to a biasing, mechanism  246 . In a preferred embodiment, biasing mechanism  246  is capable of urging applicator  202  toward an insulating glass unit with a preselected force. In a preferred method in accordance with the present invention, the preselected force provided by the biasing mechanism may be selected to yield a sealant bead having a desired thickness.  
     [0057] Biasing mechanism  246  may comprise various components without deviating from the spirit and scope of the present invention. Examples of components which may be suitable in some applications include solenoids, air cylinders, motors and springs. In one embodiment, biasing mechanism  246  comprises an air cylinder coupled to a slide. An exemplary air cylinder which may be suitable in some applications is available from Compact Air Products of West Minster, S.C., U.S.A. which identifies it by the number SD228X38. An exemplary slide which may be suitable in some applications is commercially available from THK America of Schaumburg, Ill., U.S.A. which identifies it by the number SR25.  
     [0058] As shown in FIG. 8, biasing mechanism  246  is coupled to a rotary actuator  243 . In a preferred embodiment, rotary actuator  243  is capable of rotating biasing mechanism  246  and applicator  202  about an axis of rotation. Many embodiments of rotary actuator  243  are possible without deviating from the spirit and scope of the present invention. Rotary actuators which may be suitable in some applications are commercially available from Kollmorgen Corporation of Radford, Va.  
     [0059] Rotary actuator  243  is coupled to a gantry  242  that is preferably capable of moving rotary actuator  243 , biasing mechanism  246 , and applicator  202  in three-dimensional space. Various embodiments of gantry  242  are possible without deviating from the spirit and scope of the present invention. For example, gantry  242  may include one or more linear actuators and one or more rotary actuators. In the embodiment of FIG. 8, gantry  242  includes an x-axis linear actuator  244 A and a y-axis linear actuator  244 B. It is to be appreciated that many embodiments of a linear actuator are possible without deviating from the spirit and scope of the present invention. Linear actuators which may be suitable in some applications are commercially available from Lintech Corporation of Monrovia, Calif. and Tol-o-matic Corporation of Hamel, Minn.  
     [0060] System  206  further includes a sealant source  209  which is in fluid communication with applicator  202 . Various embodiments of sealant source  209  are possible without deviating from the spirit and scope of the present invention. Sealant sources which may be suitable in some applications are commercially available from Graco Incorporated of Minneapolis, Minn.  
     [0061]FIG. 9 is a perspective view of an illustrative assembly  236  including applicator  202  of FIG. 8 and an insulating glass unit  208 . In the embodiment of FIG. 9, applicator  202  has been positioned within a first channel  240 A of insulating glass unit  208 . First channel  240 A is defined by the inside face of a first pane  220 , the inside face of a second pane  222 , and a spacer  206 . Applicator  202  may be moved longitudinally along first channel  240 A, for example, by gantry  242  of FIG. 8. While applicator  202  is moved along first channel  240 A, a first deposit may be applied to the inside face of first pane  220 . An applicator arm  272  of applicator  202  may be used to apply a second deposit to an outside face  278  of first pane  220 . For clarity of illustration, the first deposit and the second deposit are not shown in FIG. 9. In some methods in accordance with the present invention, applicator  202  may also apply sealant deposits to an inside surface of second pane  222  and to a surface of spacer  206 .  
     [0062] When applicator  202  reaches a first corner  280  of insulating glass unit  208 , applicator  202  may be positioned within a second channel  240 B of insulating glass unit  208 . For example, applicator  202  may be moved in three dimensional space by gantry  242 , and/or applicator  202  may be rotated by rotary actuator  243 .  
     [0063]FIG. 10 is an additional perspective view of assembly  236  of FIG. 9. In the embodiment of FIG. 10, applicator  202  has been positioned within second channel  240 B of insulating glass unit  208 . Second channel  240 B is defined by the inside face of first pane  220 , the inside face of second pane  222 , and a spacer  206  of insulating glass unit  208 . In FIG. 10, it may be appreciated that applicator  202  has been rotated. In the embodiment of FIG. 10, applicator  202  has been rotated by approximately 90 degrees.  
     [0064]FIG. 11 is block diagram of a sealant application system  300  in accordance with an additional exemplary embodiment of the present invention. Sealant application system  300  includes an applicator  302  that is coupled to a biasing mechanism  346  comprising a slide  382  and an air cylinder assembly  339 . Slide  382  comprises a base  384  and a saddle  386 . As shown in FIG. 11 a plurality of bearings  388  are disposed between base  384  and saddle  386 . In a preferred embodiment, the motion of saddle  386  relative to base  384  is guided by bearings  388 . In this preferred embodiment, saddle  386  is free to move along an axis  390 . Various embodiments of slide  382  are possible without deviating from the spirit and scope of the present invention. An exemplary slide which may be suitable in some applications is commercially available from THK America of Schaumburg, Ill. U.S.A. which identifies it by the number SR35.  
     [0065] Air cylinder assembly  339  of biasing mechanism  346  comprises a piston  396  and a cylinder  394 . As shown in FIG. 11, cylinder  394  and piston  396  define a chamber  392 . A regulator  398  is disposed in fluid communication with chamber  392  of cylinder assembly  336 . Regulator  398  is preferably capable of controlling the fluid pressure within chamber  392 . Regulator  398  is coupled to a supply line  399 . In some useful embodiments, supply line  399  is disposed in fluid communication with a source of compressed air.  
     [0066] In FIG. 11, it may be appreciated that saddle  386  of slide  382  and piston  396  of air cylinder assembly  339  are both coupled to applicator  302 . In the embodiment of FIG. 11, slide  382  and air cylinder assembly  339  cooperate to exert a preselected force upon applicator  302  along axis  390 . In a preferred embodiment the magnitude of the force maybe preselected by applying a desired pressure to chamber  392  via regulator  398 . In a particularly preferred embodiment, the pressure within chamber  392  may be selected such that sealant application system  300  applies a bead of sealant having a desired thickness.  
     [0067] In the embodiment of FIG. 11, base  384  of slide  382  and cylinder  394  of air cylinder assembly  339  are both coupled to a rotary actuator  343 . Rotary actuator  343  is preferably capable of rotating applicator  302  and biasing mechanism  346  about an axis of rotation. Rotary actuator  343  is coupled to a gantry  342 . Gantry  342  is preferably capable of moving rotary actuator  343 , biasing mechanism  346 , and applicator  302  in three dimensional space.  
     [0068]FIG. 12 is a perspective view of applicator  302  of sealant application system  300  of FIG. 11. In FIG. 12, it may be appreciated that applicator  302  includes an applicator body  348 , a mounting flange  368 , and a plate  370 . Mounting flange  368  and applicator body  348  define a cavity  350  terminating at an inlet port  352 . In the embodiment of FIG. 12, plate  370  and applicator body  348  define a flow channel  340  that is preferably in fluid communication with cavity  350  and inlet port  352 . Applicator body  348  also defines a plurality of lumens  326 , which are preferably also in fluid communication with cavity  350  and inlet port  352  of applicator  302 .  
     [0069] In a preferred embodiment, flow channel  340  and lumens  326  are configured such that sealant is dispensed substantially across the entire width of a face portion  304  of applicator  302 . In the embodiment of FIG. 12, face portion  304  of applicator  302  includes a first generally curved surface  354 A, a second generally curved surface  354 B, a first generally flat surface  356 A and a second generally flat surface  356 B.  
     [0070]FIG. 13 is a plan view of an illustrative assembly  336  including applicator  302  and biasing mechanism  346  of FIG. 13. Assembly  336  also includes an insulating glass unit  308  that is shown in cross section in FIG. 13. In the assembly of FIG. 13, applicator  302  has been positioned within a channel  340  of insulating glass assembly  336 . Channel  340  is defined by a first pane  320 , a second pane  322 , and a spacer  306  interposed between first pane  320  and second pane  322 . A sealant bead  358  is interposed between applicator  302  and spacer  306 .  
     [0071] Applicator  302  is coupled to biasing mechanism  346  by a plurality of screws  360 . Biasing mechanism  346  preferably urges applicator  302  towards spacer  306  of insulating glass unit  308  with a force F. In FIG. 13, force F is represented with an arrow.  
     [0072] In a preferred method in accordance with the present invention, a sealant  362  is directed through lumens  326  and flow channel  340  of applicator  302  to form sealant bead  358 . Sealant bead  358  preferably applies pressure on face portion  304  of applicator  302 . The pressure applied to face portion  304  of applicator  302  balances force F which urges applicator  302  towards spacer  306 . Advantageously, there is a relationship between the thickness of sealant bead  358  and the magnitude of the pressure applied to face portion  304  of applicator  302 . Thus, methods in accordance with the present invention are possible in which force F is selected to yield a desired thickness of sealant bead  358 .  
     [0073]FIG. 14 is a perspective view of an additional embodiment of an applicator  402  in accordance with the present invention. Applicator  402  includes body member  424  defining a plurality of lumens  426 . Body member  424  of applicator  402  also defines a first cutout  428  which is in fluid communication with one of the lumens  426 . First cutout  428  advantageously allows sealant to be dispensed along a first side  430  of applicator  402 . In FIG. 14, it may also be appreciated that body member  424  defines a second cutout  432  in fluid communication with another one of the lumens  426 . Applicator  402  also includes a mounting flange  468  defining an inlet port  452 . Inlet port  452  is preferably in fluid communication with lumens  426 . Second cutout  432  allows sealant to be dispensed along a second side  434  of applicator  402 .  
     [0074]FIG. 15 is a plan view of an assembly  436  including the applicator  402  of FIG. 14. In the embodiment of FIG. 15, applicator  402  is being used to apply a first bead  466 A and a second bead  466 B to an insulating glass unit  408 . As shown in FIG. 15, applicator  402  is coupled to a biasing mechanism  446 .: In a preferred embodiment, biasing mechanism  446  urges applicator  402  towards a spacer  406  of insulating glass unit  408 . In the embodiment of FIG. 42, the biasing force is represented by an arrow. In the assembly of FIG. 15, a face portion  404  of applicator  402  has been urged against spacer  406  by biasing mechanism  446 .  
     [0075]FIG. 16 is a perspective view of an additional embodiment of an applicator  502  in accordance with the present invention. In the embodiment of FIG. 16, applicator  502  includes a body member  524  and an applicator arm  572  fixed to the body member. Body member  524  includes a mounting flange portion  568 . Body member  524  defines a cavity  550  in fluid communication with an inlet port  552  defined by a mounting flange portion  568  of body member  524 . Applicator arm  572  preferably defines a sealant path in fluid communication with cavity  550  and inlet port  552 . In FIG. 16, it may be appreciated that body member  524  and applicator arm  572  define a gap  574 . In a preferred embodiment gap  574  is configured to receive a pane of an insulating glass unit.  
     [0076]FIG. 17 is a plan view of an illustrative assembly  536  including applicator  502  of FIG. 16 and an insulating glass unit  508 . In the embodiment of FIG. 17, insulating glass unit  508  is shown in cross section, and includes a first pane  520 , a second pane  522 , and a spacer  506  interposed between first pane  520  and second pane  522 . Insulating glass unit  508  also includes a channel  540  defined by first pane  520 , second pane  522 , and spacer  506 . In the embodiment of FIG. 17, body member  524  of application  538  is partially disposed within channel  540 . In FIG. 17 it may be appreciated that applicator arm  572  of applicator  502  defines a sealant path  576 . In a preferred embodiment, applicator arm  572  and sealant path  576  are configured to apply a bead  566  to an outside face  578  of first pane  520  of insulating glass unit  508 .  
     [0077]FIG. 18 is a plan view of an additional illustrative assembly  636  including an insulating glass unit  608  and an applicator  602  in accordance with an additional embodiment of the present invention. Applicator  602  of FIG. 18, includes an applicator body  648 , a first applicator arm  672 A, and a second applicator arm  672 B. First applicator arm  672 A defines a first sealant path  676 A, and second applicator arm  672 B defines a second sealant path  676 B. In a preferred embodiment first applicator arm  672 A and first sealant path  676 A are configured to apply a first bead  665 A to an outside surface of first pane  620 . Also in a preferred embodiment, second applicator arm  672 B and second sealant path  676 B are configured to apply a second bead  665 B to an outside face of second pane  622 .  
     [0078] Several forms of invention have been shown and described, and other forms will now be apparent to those skilled in the art. It will be understood that embodiments shown in drawings and described above are merely for illustrative purposes, and are not intended to limit the scope of the invention defined in the claims which follow.