Abstract:
An apparatus and method for securing an edge of a paintless type film gore. A fluid sealant material is beaded along the edge of the gore using a bead striping apparatus. The striping apparatus comprises a serrated wheel rotatably coupled to a housing which contains the fluid sealant. The sealant is transferred to the wheel and subsequently is transferred the gore edge as the wheel is rolled.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Technical Field of the Invention  
           [0002]    The present invention relates generally to the field of paintless applications and, more particularly, to an apparatus and process for applying a sealant bead to a paintless film edge.  
           [0003]    2. Description of Related Art  
           [0004]    Millions of dollars are presently spent each year painting and de-painting aircraft. Additionally, the hazardous materials associated with the paints and solvents used for such painting and de-painting contribute to polluting the environment.  
           [0005]    A new paintless technology called “Applique” offers many advantages over paints and paint systems currently used. The new coating significantly reduces hazardous material use, cuts fuel cost, improves corrosion protection, and reduces aircraft weight growth.  
           [0006]    The applique is basically a paint-replacement adhesive film which is applied to typically painted portions of an aircraft, similar to window tinting films applied to car windows. The film is applied in gores or patches with each successive layer slightly overlapped on the next.  
           [0007]    One concern with the application technique of the applique is the tendency of the film edges to peel or tear apart under the extreme force of air rushing over the surface at high speeds. Despite the film being self-adhesive, the edges must still be reinforced with, for example, a sealant bead or edging. Testing has shown that the new paintless film, with a beaded edge, can successfully sustain flights at approximately twice the speed of sound.  
           [0008]    Currently, the adhesive bead application includes using parallel bands of masking tape to form a narrow channel over the edge of the gore into which a sealant is applied. Subsequently, the sealant is skived. Intersecting corners must be done sequentially, after the first of the intersecting edges has cured. Covering an aircraft in this manner is very labor intensive and time consuming both of which greatly increases the cost of applying the film.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention achieves technical advantages as an apparatus and method for securing an edge of a paintless type film gore. A fluid sealant material is striped along the edge of the gore using a striping apparatus. The striping apparatus comprises a serrated application wheel rotatably coupled to a housing which contains the fluid sealant. The sealant is transferred to the wheel for application to the gore as the wheel is rolled along the edge to be secured.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    For a more complete understanding of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawings wherein:  
         [0011]    [0011]FIG. 1 illustrates a gore of a paintless film applied to an area of an exemplary flow surface;  
         [0012]    [0012]FIG. 2A illustrates a bead sealant striping apparatus in accordance with an exemplary embodiment of the present invention;  
         [0013]    [0013]FIG. 2B illustrates a bead wheel in accordance with an embodiment of the present invention;  
         [0014]    [0014]FIG. 3 illustrates another sealant bead striping apparatus in accordance with an exemplary embodiment of the present invention;  
         [0015]    [0015]FIG. 4 illustrates a multiple wheel assembly head in accordance with another embodiment of the present invention; and  
         [0016]    [0016]FIG. 5 illustrates a bead wheel striping apparatus in accordance with an exemplary embodiment of the present invention including the multiple wheel assembly head and a sealant container.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    The numerous innovative teachings of the present application will be described with particular reference to the presently preferred exemplary embodiments. However, it should be understood that this class of embodiments provides only a few examples of the many advantageous uses and innovative teachings herein. In general, statements made in the specification of the present application do not necessarily delimit any of the various claimed inventions. Moreover, some statements may apply to some inventive features, but not to others.  
         [0018]    Referring now to FIG. 1, there is illustrated a gore  105  of a paintless film applied to an area of an exemplary flow surface  110 . The arrows indicate an exemplary air flow direction. The painless film has an adhesive backing for application to the flow surface  110 . The preferred method of application would overlap the trailing edge of a gore over the leading edge of the one aft. While practical for initial applique application, subsequent repairs will almost always have exposed leading edge overlaps. In this illustration, the front edge  120  of the gore  105  would be the most vulnerable to peeling or tearing due to the force of the air flow, however, all edge are vulnerable to varying degrees. Generally, the adhesive backing is inadequate to prevent this type of peeling, thus, further reinforcement must be used to protect the integrity of the gore  105 .  
         [0019]    A technique in accordance with an embodiment of the present invention is to apply a trimming edge, bead, or stripe of sealant just at the edges of the gore  105 . The bead of sealant is applied using an edge sealing apparatus in accordance with an embodiment of the present invention and the bead is subsequently cured. Curing can include applying an air flow and/or heat to the applied bead to accelerate the cure rate.  
         [0020]    Referring now to FIG. 2A, there is illustrated a bead sealant striping apparatus  200  in accordance with an exemplary embodiment of the present invention. The sealant bead striping apparatus  200  includes a bead wheel  210  mounted in a housing  205 . The wheel  210  is preferably of a width to coincide with that width of sealant needed to effectively secure the gore  105 , typically {fraction (3/16)} inch to ¼ inch. The wheel  210  is rolled along the edges of the gore  105  and deposits a selected sealant in an even layer in a manner similar to applying a paint pin stripe to a car.  
         [0021]    The housing  205  has a reservoir ramp  208  for guiding sealant to the bead wheel  210 . The sealant is stored in the housing  205  and the housing  205  can be of a size to fit into a neck of a larger type container for storing sealant which is to be laid in the form of a bead by rolling the wheel  210  along the edge of a paintless film gore  105 , for example. The sealant can include, for example, a one-component adhesive sealant with a viscosity of between 60 and 8000 centipoises and a two-part epoxy system ranging in viscosity between 60 to 8000 centipoises. As is well known, a variety of curable epoxy resin compositions are prepared by blending various types of epoxy resin, compounding resin and additives which vary widely in nature. In general, reactive diluents, plasticizers, solvents and other additives are selected to form compositions having an appropriate viscosity. The materials can be either room temperature cured or accelerated by means of applying heat or air as aforementioned.  
         [0022]    In the past, various types of striping devices have been known for applying a paint stripe to a surface. These devices generally include a striper wheel which is journalled on a housing which is in communication with a container for housing paint. A representative prior art pin striper is exemplified by U.S. Pat. No. 1,988,710 the description of which is incorporated herein by reference. However, the prior art and paint pin striping devices are subject to certain shortcomings when used for applying sealants. For example, more viscous materials, such as a sealant, are not laid properly by the paint pin striper to form a sealant bead on an application surface.  
         [0023]    In accordance with an embodiment of the present invention, the bead wheel  210  is rotationally mounted by a pin  211  and, as the wheel rotates, it comes in contact with sealant guided through the reservoir ramp from the housing  205  or container. Typical paint pin striping tools dispense paint onto a wheel as the wheel rotates and comes into close contact with a dispenser, however, such close contact does not allow a proper application, of more viscous materials such as sealants. In accordance with an embodiment of the present invention, the reservoir ramp  208  is sized (i.e. enlarged as a function of increased viscosity) to enable a proper flow of sealant to the bead wheel  210 .  
         [0024]    Referring now to FIG. 2B there is illustrated a bead wheel  210  in accordance with an embodiment of the present invention. The bead wheel  210  is configured with deep serrations  215  around the circumference. The serrations  215  act as small reservoirs and are filled with sealant as each serration  215  passes the reservoir ramp  208  (FIG. 2A). Subsequently, the sealant is transferred from the serrations  215  to the application surface as the wheel  210  is rolled.  
         [0025]    Referring now to FIG. 3, there is illustrated another sealant bead striping apparatus  300  in accordance with an exemplary embodiment of the present invention. The sealant bead striping apparatus  300  includes the bead wheel  210  and housing  205  with reservoir ramp  208 . The housing  205  contains the sealant which is applied as a bead to the gore edge  120  (FIG. 1). The housing  205  can be of a size to fit into or couple to a larger type sealant container. The sealant is guided from the housing  205  to the bead wheel  210  as indicated by arrow  307 . Sealant is applied to the bead wheel  210  (into the serrations  215 ) as the bead striping apparatus  300  is rolled in the direction indicated by the arrow  309 . As the wheel  210  turns, each serration  215  passes through an applicator gap  301  which applies the sealant. Subsequently, the sealant is transferred to the gore edge  120  as the serrations  215  make contact with the application surface.  
         [0026]    The application gap  301  is sized to accommodate the viscous sealant material to enable a controllable consistent flow of sealant onto the bead wheel  210 . For example, a more viscous sealant requires a larger gap distance than a less viscous sealant. The bead wheel  210  is mounted to a movable sleeve  305  which is coupled to the reservoir  208 . The sleeve  305  can be adjusted along the reservoir in the direction of the arrow  309 . Adjustment of the sleeve varies the gap distance in which the gap distance is increased for a higher viscosity and decreased for a lower viscosity.  
         [0027]    To further improve consistent sealant bead application for various viscous sealants, the sealant bead striping apparatus  300  is also configured with replaceable bead wheels in which bead wheels with deeper serrations are used for higher viscosity sealants and more shallow serrations are used for lower viscosity sealants.  
         [0028]    Referring now to FIG. 4, there is illustrated a multiple wheel assembly head  400  in accordance with another embodiment of the present invention. The head  400  is shown with three bead striping wheels, however, two or more than three can be used. Typically, round paintless film cutouts  130  (FIG. 1) are used to expose fastening devices, such as screws, which are exposed on the flow surface of an airplane wing, for example. The multiple wheel assembly head  400  is preferably used in such application to apply a sealant bead around a circular edge of the round cutout  130 . Each wheel assembly includes a bead wheel  210  and reservoir  200  (as illustrated in FIG. 2A) coupled to a mounting plate  405 .  
         [0029]    Referring now to FIG. 5, there is illustrated a bead wheel striping apparatus  500  in accordance with an exemplary embodiment of the present invention including the multiple wheel assembly head  400  and a sealant container  505 . The head  405  is configured to couple to the sealant container  505  and to enable a sealant material to flow from the sealant container  505  to the reservoir of each bead wheel  210 . The bead wheels  210  are coupled to the head  405  at equal distance from a center axis  510 . Thus, as the wheels  210  are rolled around the gore  130  by a one-third turn or twist about the axis  510 , a circular sealant bead is applied. A head configured with two wheels would require a one-half turn about the axis  510  to completely seal the edge of the round gore  130 .  
         [0030]    The striping apparatus  500  can also include a pressure member  515  for applying force to the sealant to assist with sealant flow to the bad wheel  210 . The pressure member  515  includes a plunger head which sits inside the sealant container  505  and is slidably movable in a parallel direction with respect to the axis  510 , for example. Additionally, the sealant container can be divided or separated by an inner wall so to accommodate a two-part epoxy system in which the two parts are combined in a chamber adjacent to the head  405  just before application to the bead wheel(s)  210 .  
         [0031]    Although a preferred embodiment of the method and system of the present invention has been illustrated in the accompanied drawings and described in the foregoing Detailed Description, it is understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit of the invention as set forth and defined by the following claims.