Patent Publication Number: US-8986491-B2

Title: Composite panel insert ring and method of using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation patent application of U.S. patent application Ser. No. 12/683,714, filed on Jan. 7, 2010, now U.S. Pat. No. 8,409,395, entitled Composite Panel Insert Ring and Method of Using the Same, all of the teachings of which are incorporated herein. 
    
    
     STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
     Not Applicable 
     BACKGROUND 
     The present disclosure is related generally to composite structures. More specifically, the present disclosure is directed toward an insert ring for a composite structure to provide a thru-hole within the composite structure and to fluidly seal internal compartments located therein. 
     Composite structures have been used extensively in the aerospace and marine industries. For instance, composite panels may be used to form the wing or fuselage of an aircraft, or a portion of a ship&#39;s hull or deckhouse. The composite panels are configured to provide suitable strength and stiffness, while at the same time defining a storage boundary or capacity for storage of various contents (i.e., fuel) therein. 
     It is understood that today&#39;s aircraft are generally complex electro-mechanical systems, which may have components formed within or extending through the composite structure. For example, a need may exist for passing electrical wiring or mechanical components from one side of the composite structure to the other side. A thru-hole may be formed within the composite structure to facilitate such passage. 
     Although forming the thru-hole in the composite structure allows for passage of the electrical or mechanical components, it may also compromise the strength or storage capacity of the composite structure. In particular, the fluid integrity may be compromised “externally” as well as “internally.” 
     The “external” fluid integrity may be compromised by opening the internal compartments to the surrounding environment. As a result, the contents stored within the internal compartments may leak into the surrounding environment. This may lead to hazardous consequences in the event fuel or other hazardous materials are leaked from a storage compartment in an aircraft or ship structure into the surrounding environment. 
     The “internal” fluid integrity may be compromised by opening an internal compartment to an adjacent internal compartment. This may allow the contents in one internal compartment (i.e., fuel tank) to flow into an adjacent internal compartment, which may contaminant, degrade, or trap the contents of the respective internal compartments. 
     In view of the foregoing, there is a need in the art for a device configured to provide a protective casing around a thru-hole formed within a composite structure, while at the same time fluidly sealing the internal compartments formed within the composite structure. 
     BRIEF SUMMARY 
     There is provided a method of forming a thru-hole within a composite structure having a plurality of internal compartments. An insert ring is connected to the composite structure to create a protective layer around the periphery of a penetration formed within the composite structure. An adhesive is disposed between the composite structure and the insert ring to create a fluid-tight seal between the insert ring and the internal compartments. In this regard, the fluid-tight seal mitigates fluid flow between the internal compartments, as well as fluid flow into the ring. 
     One embodiment of the method includes providing an insert ring including a male portion and a female portion. The male portion includes a cylindrical male ring and an annular male flange extending radially outward from the male ring. The female portion includes a cylindrical female ring and an annular female flange extending radially outward from the female ring. The female ring and male ring are cooperatively engageable to define a cylindrical extension extending unobstructed through the insert ring. The penetration wall is lined with adhesive or sealant, and the male portion and female portion are engaged to the structure. The male portion and/or the female portion are in compressive engagement with the structure, with the cylindrical extension being disposed within the penetration. The adhesive is disposed between the insert ring and the structure to couple the insert ring thereto and to create a fluid tight seal between the respective ones of the plurality of horizontally oriented, vertically layered internal compartments, and between the plurality of internal compartments and the insert ring. 
     The adhesive may be applied to the insert ring before engaging the insert ring to the structure. The adhesive may also be applied to line the penetration wall before the insert ring is engaged with the structure. 
     The insert ring may be engaged with the structure to dispose the male flange adjacent the first exterior surface and to dispose the female flange adjacent the second exterior surface. Adhesive may be disposed between the male flange and the first exterior surface to create a fluid tight seal between the male flange and the first exterior surface. Adhesive may also be disposed between the female flange and the second exterior surface to create a fluid tight seal between the female flange and the second exterior surface. 
     The male portion and the female portion may be threadably engageable with each other. Adhesive may be disposed between the male portion and the female portion to bond the male portion to the female portion and to create fluid tight seal therebetween. 
     Another embodiment relates to an insert for use with a composite panel for forming a thru-hole through the composite panel, wherein the composite panel includes a plurality of internal compartments and a penetration extending through the composite panel. The insert includes an insert ring including a male portion and a female portion. The male portion includes a male ring and a male flange extending radially outward from the male ring. The female portion includes a female ring and a female flange extending radially outward from the female ring. The female ring and male ring are cooperatively engageable to define a cylindrical aperture sized and configured to be disposable within the penetration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which: 
         FIG. 1  is an upper perspective view of an insert ring having a male portion and a female portion configured to engage with a composite structure having multiple layers of internal compartments, the insert ring being in a detached configuration; 
         FIG. 2  is an upper perspective sectional view of the insert ring connected to the composite structure, the insert ring being in an attached configuration; 
         FIG. 3  is a partial, enlarged side view of the insert ring and composite structure depicted in  FIG. 2 ; 
         FIG. 4  is a side sectional view of the insert ring in a detached configuration; and 
         FIG. 5  is side sectional view of the insert ring connected to a composite structure having a single layer of internal compartments. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below in connection with the appended drawings is intended as a description of certain embodiments of the present disclosure, and is not intended to represent the only forms that may be developed or utilized. The description sets forth the various functions in connection with the illustrated embodiments, but it is to be understood, however, that the same or equivalent functions may be accomplished by different embodiments that are also intended to be encompassed within the scope of the present disclosure. It is further understood that the use of relational terms such as first and second and the like are used solely to distinguish one from another entity without necessarily requiring or implying any actual such relationship or order between such entities. 
     Referring now to the drawings, wherein the showings are for purposes of illustrating an embodiment of the present disclosure, and not for purposes of limiting the same, there is shown an insert ring  10  configured for use with a composite structure  12 . The composite structure  12  includes a plurality of horizontally oriented, vertically layered internal fluid storage compartments  14 ,  16 ,  18 ,  20  (See  FIG. 3 ) arranged in a stacked configuration. In this regard, there are multiple levels of internal compartments  14 ,  16 ,  18 ,  20  separated vertically by horizontal walls  21 ,  23  (See  FIG. 3 ). A penetration wall  25  (See  FIG. 1 ) extends through the composite structure  12  to define a penetration  22  (See  FIG. 1 ), which extends through internal compartments  14 ,  16  and  20 . The insert ring  10  is connected to the composite structure  12  to fluidly seal internal compartments  14 ,  16 , and  20 , while also providing a protective layer around the periphery of the penetration  22 . 
     The composite structure  12  may define a variety of sizes and shapes. For instance, the composite structure  12  may include portions of an aircraft ring or fuselage, or the hull of a marine vessel. The internal compartments  14 ,  16 ,  18 ,  20  located within the composite structure  12  may be used to store various contents, such as fuel, coolant water, oil, or other contents known in the art. Those skilled in the art will appreciate that the number of compartment layers may be varied without departing from the spirit and scope of the present disclosure. When the penetration  22  is formed through the composite structure  12 , various internal compartments may be opened to the external environment. For instance, internal compartments  14 ,  16 ,  20  are exposed to the external environment in the composite structure  12  depicted in  FIG. 3 . In this regard, the contents stored within internal compartments  14 ,  16 , and  20  may flow out of their respective compartments. Furthermore, contents within the surrounding environment may leak into the internal compartments  14 ,  16 ,  20 . Accordingly, the insert ring  10  is connected to the composite structure  12  to fluidly seal internal compartments  14 ,  16 , and  20 . The insert ring  10  may be disposed in compressive fluid tight engagement with the composite structure  12 . 
     The composite structure  12  includes a first exterior surface  24  (See  FIGS. 1-5 ) and an opposing second exterior surface  26  (See  FIGS. 1-5 ) to define a structure thickness, “T” (See  FIG. 4 ). The penetration wall  25  formed within the composite panel  12  extends through the thickness T, from the first exterior surface  24  to the second exterior surface  26 . 
     The insert ring  10  includes two cooperatively engageable halves which sandwich the composite structure  12 . The insert ring  10  is shown in a detached configuration in  FIG. 1 , and an attached configuration in  FIG. 2 . One embodiment of the insert ring  10  includes a male portion  28  (See  FIG. 1 ) and a female portion  30  (See  FIG. 1 ). The male portion  28  includes a male longitudinally extending (cylindrical) ring  32  and a male flange  34  extending radially outward from the male ring  32 . The male flange  34  defines a male flange inner surface  40  (See  FIG. 4 ) which is disposable adjacent the first exterior surface  24  when the insert ring  10  is connected to the composite structure  12 . Likewise, the female portion  30  includes a female longitudinally extending (cylindrical) ring  36  and a female flange  38  extending radially outward from the female flange  36 . The female flange  38  defines a female flange inner surface  42  (See  FIG. 4 ) which is disposable adjacent the second exterior surface  26  when the insert ring  10  is coupled to the composite structure  12 . 
     The male ring  32  and the female ring  36  are configured to be cooperatively engageable with each other to define unobstructed cylindrical aperture  35 . (See  FIGS. 1 ,  2 ). In the embodiment depicted in the drawings, the male ring  32  is circumscribed by the female ring  36  when the male ring  32  is engaged to the female ring  36 . In this manner, the outer diameter of the male ring  32  is slightly smaller than the inner diameter of the female ring  36  to allow for insertion of the male ring  32  into the female ring  36 . When the male ring  32  is engaged with the female ring  36 , the distance between the male flange inner surface  40  and the female flange inner surface  42  is slightly larger than the thickness T of the composite structure  12  to clamp the composite structure  12  between the male flange  34  and the female flange  38 . 
     The male ring  32  and female ring  36  are preferably configured to define a length which extends at least through the penetration  22 . However, it is contemplated that the male ring  32  and/or the female ring  36  may define a length which is greater than the penetration  22  to extend outside of the penetration  22 , or alternatively, define a length which is less than the penetration  22 . When the male ring  32  and/or female ring  36  defines a length which is less than the penetration  22 , a filler material (such as adhesive, described below) may be used to fill any unwanted gaps. 
     Engagement between the male ring  32  and the female ring  36  may be facilitated by corresponding threads and grooves. In one embodiment, the male ring  32  includes one or more threads  52  which cooperatively engage with grooves  54  formed on the female ring  36 . Engagement between the male ring  32  and the female ring  36  may be achieved by rotating the male ring  32  relative to the female ring  36  in a tightening direction without the use of a tool. As the male ring  32  continues to rotate relative to the female ring  36  in the tightening direction, the engagement is tightened. Furthermore, as the male ring  32  rotates relative to the female ring  36  in the tightening direction, the distance between the male flange  34  and the female flange  38  decreases to tighten the engagement with the composite structure  12 . 
     Those skilled in the art will appreciate that other embodiments of the insert ring  10  may include threads formed on the female ring  36  and corresponding grooves formed on the male ring  32 . Furthermore, it is contemplated that other embodiments may include male rings  32  and female rings  36  that are non-circular in shape. In this manner, the male ring  32  may engage to the female ring  36  through other engagement means, such as press-fit engagement, or other engagement means known by those skilled in the art. 
     The male portion  28  and/or the female portion  30  may be comprised of a nylon material and be formed by a selective laser sintering manufacturing process. In this respect, the male and female portions  28 ,  30  may be formed in a layerwise fashion. However, other materials and manufacturing processes known by those skilled in the art may also be used without departing from the spirit and scope of the present disclosure. For a more detailed discussion pertaining to selective laser sintering, please refer to U.S. Pat. No. 7,514,649, entitled Built-in Attachment Device Using Selective Laser Sintering, owned by Northrop Grumman Corporation, the Assignee of the present patent application. 
     With the basic structural components of the insert ring  10  being described above, the following discussion will now focus on a method of connecting the insert ring  10  to the composite structure  12 . The composite structure  12  is provided and a penetration  22  is formed through the composite structure  12 . An adhesive  50  or bonding material is disposed between the insert ring  10  and the composite structure  12  to create a fluid tight seal between the insert ring  10  and the composite structure  12 , and to fluidly seal the internal fluid storage compartments  14 ,  16 ,  20  disposed adjacent the penetration  22 . The adhesive  50  is preferably a composition including sealing and adhering properties, such as EA9394 paste adhesive, marketed by Henkel Corporation. The adhesive  50  should have stable properties, such as strength, through a typical temperature range of −50° F. to 220° F. It should also have good resistance to fluid degradation, specifically fuels such as JP-F or JP-8. 
     It is contemplated that the adhesive  50  may be disposed on the penetration wall  25  before the insert ring  10  is engaged with the composite structure  12 . Alternatively, the adhesive  50  may be disposed on the insert ring  10  before the insert ring  10  is engaged with the composite structure  12 . It is also contemplated that the adhesive  50  may be disposed on both the penetration wall  25  and the insert ring  10  before the insert ring  10  is engaged with the composite structure  12 . In a preferred embodiment, adhesive  50  is applied to both the penetration wall  25  and the insert ring  10  to ensure squeeze out and full sealing. The remaining adhesive will then be removed around the periphery of the insert ring  10 . 
     In the depicted embodiment, the female ring  36  defines an outer contact surface  44  which interfaces with the penetration wall  25  of the composite structure  12 . In this respect, the outer contact surface  44  defines a shape that is complementary to the shape of the penetration wall  25 . Adhesive  50  or bonding material is disposed between the outer contact surface  44  to create a fluid tight engagement between the outer contact surface  44  and the penetration wall  25 , as well as to fluidly seal internal compartments  14 ,  16  and  20 . 
     It is also contemplated that a bonding material, sealant or adhesive  50  may be disposed between the male flange  34  and the composite structure  12 , and the female flange  38  and the composite structure  12 . In this manner, adhesive  50  may be applied directly to the male flange inner surface  40  or the first exterior surface  24  to create a fluid tight seal therebetween. Likewise, adhesive  50  may be disposed between the female flange inner surface  42  or the second exterior surface  26  to create a fluid tight seal therebetween. In this respect, the male ring  32  and/or the female ring  36  may be disposed in compressive fluid tight engagement with the composite structure  12 . 
     When the insert ring  10  is engaged with the composite structure  12 , the female ring  36  is inserted into the penetration  22  to dispose the outer contact surface  44  adjacent the penetration wall  25 , and to dispose the female flange inner surface  42  adjacent the second exterior surface  26 . The male ring  32  is also disposed within the penetration  22  to engage with the female ring  36  and to dispose the male flange inner surface  40  adjacent the first exterior surface  24 , defining cylindrical aperture  35 , extending unobstructed between the surfaces  24 ,  26 , through which mechanical components and/or wiring may then be passed therethrough. 
     As described above, one embodiment includes a male ring  32  and a female ring  36  having cooperating threads  52  and grooves  54 . In the embodiment depicted in  FIG. 3 , the male ring  32  includes external threads  52 , while the female ring  36  defines corresponding grooves  54 . The male portion  28  is rotated relative to the female portion  30  to tighten the engagement between the male portion  28  and the female portion  30 . Additional adhesive  50  or bonding material may be disposed between the male portion  28  and female portion  30  to further secure the male portion  28  to the female portion  30 . When the insert ring  10  is fully engaged with the composite panel  12 , the male portion  28  defines an inner ring surface which extends through the composite structure  12  to allow for passage of wiring, or mechanical elements through the composite structure  12 . Although the inner ring surface depicted in the Figures is substantially flush with the male flange  34  and the female flange  38 , it is understood that other embodiments may include an inner ring surface which extends beyond the male flange  34  and the female flange  38 . 
     In one embodiment, it may be particularly beneficial to dispose the female portion  30  in a specific position relative to the composite structure  12 . Accordingly, the female portion  30  may include a locating boss  56  (See  FIG. 1 ) protruding from the outer contact surface  44 . The composite structure  12  defines a complimentary locating notch  58  (See  FIG. 1 ) which cooperatively engages with the locating boss  56  to properly position the female portion  30  relative to the composite structure  12 . 
     The locating boss  56  and corresponding locating notch  58  may also facilitate the process of securing the male portion  28  to the female portion  30 . In the case of threadably engageable male and female portions  28 ,  30 , rotational movement of the male portion  28  relative to the female portion  30  is required to mate the male portion  28  to the female portion  30 . However, if the composite structure  12  is relatively large (i.e., an airplane fuselage bulkhead), it may be difficult for a single person to install the insert ring  10 . In particular, it may be difficult to rotate the male portion  28  with one hand, and the female portion  30  with another hand. Therefore, the engagement between the locating boss  56  and locating notch  58  may mitigate rotational movement of the female portion  30  relative to the composite structure  10 . Thus, a user may connect the female portion to the composite structure  10 , and then install the male portion  28  by rotating the male portion  28  relative to the female portion  30 . In this manner, as the user rotates the male portion  28  relative to the female portion  30 , the boss  56  and notch  58  mitigate rotation of the female portion  30 , while allowing the male portion  28  to engage with the female portion  30 . Thus, the boss  56  and notch  58  allows the insert ring  10  may be installed by a single person, rather than requiring multiple individuals for installation. 
     The composite structure  12  depicted in  FIGS. 1-4  includes several layers of internal compartments formed therein. However, referring now to  FIG. 5 , it is contemplated that the insert ring  10  may also be used with a composite structure  12  having only one layer of internal compartments. The composite structure  12  includes internal compartments  60  and  62  disposed immediately adjacent the insert ring  10 . In this embodiment, the insert ring  10  functions in substantially the same manner to fluidly seal internal compartment  60  and internal compartment  62 . 
     It is also contemplated that several embodiments of the insert ring  10  may include one or more mounting tabs  64  (See  FIGS. 4 and 5 ) connected to the male portion  28  or the female portion  30 . The mounting tabs  64  may be used to pass electrical wiring, or to hang or mount components thereto. 
     The above description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein. Further, the various features of the embodiments disclosed herein can be used alone, or in varying combinations with each other and are not intended to be limited to the specific combination described herein. Thus, the scope of the claims is not to be limited by the illustrated embodiments.