Abstract:
Apparatus and methods for providing airflow within an aircraft are disclosed. In one embodiment, a method includes forming a clamshell component, including: providing first and second spaced-apart mold members; forming first and second half-body portions, including forming at least one sheet of formable material between the first and second mold members; and coupling the first and second half-body portions to form the clamshell component. The method also includes coupling the clamshell component to a source of air; and operating the source of air to provide an airflow through the clamshell component.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application is a divisional application of co-pending, commonly-owned U.S. patent application Ser. No. 10/876,068 entitled “Apparatus and Methods for Forming Thermoplastic Clamshell Components” filed on Jun. 24, 2004, which application is incorporated herein by reference. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    This disclosure relates generally to apparatus and methods for providing airflow within an aircraft using clamshell components, including, for example, curved ducts and other structures having complex curvature. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    Methods of forming ducts and other components having complex curvature typically require the formation of a mold (or mandrel) and then a hand-layup of prepreg material onto the mold. The mold may be formed out of plaster or other suitable materials. The prepreg material is then cured, and the component is removed from the mold. Sometimes, the mold is destroyed during the removal process, necessitating the formation of another mold in order to create another component. 
         [0004]    Although desirable results have been achieved using such prior art apparatus and methods, there is room for improvement. Whereas the formation of straight ducts and other relatively simple components may be straightforward and relatively economical, the formation of components having unusual or complex curvature may be very expensive using the prior art apparatus and methods. Because many components of an aircraft involve relatively complex curvatures, the increased costs due to the formation of such components can significantly impact the cost of production of the aircraft. Therefore, novel apparatus and methods that at least partially mitigate the costs associated with forming components having complex curvature would be useful and desirable. 
       SUMMARY 
       [0005]    The present disclosure is directed to apparatus and methods for providing airflow within an aircraft using clamshell components, including, for example, curved ducts and other structures having complex curvature. Embodiments of apparatus and methods in accordance with the present disclosure may advantageously reduce the time and expense associated with forming components having unusual or complex curvature in comparison with the prior art. 
         [0006]    In one embodiment, a method of providing an airflow within an aircraft includes forming a clamshell component, including: providing first and second spaced-apart mold members; forming first and second half-body portions, including forming at least one sheet of formable material between the first and second mold members; and coupling the first and second half-body portions to form the clamshell component. The method also includes coupling the clamshell component to a source of air; and operating the source of air to provide an airflow through the clamshell component. 
         [0007]    The features, functions, and advantages that have been described above or will be discussed below can be achieved independently in various embodiments, or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Embodiments of the present disclosure are described in detail below with reference to the following drawings. 
           [0009]      FIG. 1  is a schematic side elevational view of a system for forming thermoplastic clamshell components in accordance with an embodiment of the present disclosure. 
           [0010]      FIG. 2  is an isometric view of a first mold member of the system of  FIG. 1 . 
           [0011]      FIG. 3  is an isometric view of a second mold member of the system of  FIG. 1 . 
           [0012]      FIG. 4  is a top elevational view of a portion of a component formed using the system of  FIG. 1  in accordance with an embodiment of the disclosure. 
           [0013]      FIG. 5  is an isometric view of a component formed in accordance with the disclosure integrated into an air distribution system in accordance with another embodiment of the disclosure. 
           [0014]      FIG. 6  is an isometric view of a pair of component portions formed in accordance with an alternate embodiment of the present disclosure. 
           [0015]      FIG. 7  is an isometric view of a component formed from the component portions of  FIG. 6 . 
           [0016]      FIG. 8  is a partially-exploded, isometric view of a pair of component portions formed in accordance with another embodiment of the present disclosure. 
           [0017]      FIG. 9  is an isometric view of the first and second portions of  FIG. 8  being coupled together in accordance with another embodiment of the present disclosure. 
           [0018]      FIG. 10  is an isometric view of an apparatus for bonding a pair of components together in accordance with the disclosure. 
           [0019]      FIG. 11  is an enlarged, partial isometric view of the bonding apparatus of  FIG. 10 . 
           [0020]      FIGS. 12 through 15  are isometric views of a pair of components being coupled together in accordance with further embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The present disclosure relates to apparatus and methods for forming thermoplastic clamshell components. Many specific details of certain embodiments of the disclosure are set forth in the following description and in  FIGS. 1-15  to provide a thorough understanding of such embodiments. One skilled in the art, however, will understand that the present disclosure may have additional embodiments, or that the present disclosure may be practiced without several of the details described in the following description. 
         [0022]    Generally speaking, apparatus and methods for forming thermoplastic clamshell components in accordance with the present disclosure may include positioning a sheet of thermoplastic material between a pair of mold members, forming the thermoplastic material between the mold members to form a half-body component, and then joining two or more half-body components together to form a thermoplastic clamshell component. As used in the following description, the term “clamshell” generally refers to a process that uses tools to press form two or more segments of a part, and then joining those segments together in a manner that creates a whole functioning part. There are at least two approaches used to accomplish such processes. In a first approach, the two half-body segments may be press-formed in a press or other suitable device, and then joined together in a subsequent step outside the press. Alternately, the half-body segments may be press-formed in a press, and may also be joined together in the press, either simultaneously or subsequently with the press-forming of the half-body segments. In the following discussion, unless otherwise specified, the various apparatus and methods in accordance with the present disclosure described below are applicable to both of these alternate approaches. 
         [0023]      FIG. 1  is a schematic, side elevational view of a system  100  for forming thermoplastic clamshell components in accordance with an embodiment of the present disclosure. In this embodiment, the system  100  includes a first mold member  102 , and a second mold member  104  position above the first mold member  102 . A thermoplastic sheet  106  is positioned between the first and second mold members  102 ,  104 . An actuator  108  is coupled to the second mold member  104  and is adapted to controllably move the second mold member  104  into engagement with the thermoplastic sheet  106 , forming the thermoplastic sheet  106  between the first and second mold members  102 ,  104 . 
         [0024]    The thermoplastic sheet  106  may be, for example, an Ultem® sheet, or a Reinforced Thermoplastic Laminate (RTL) sheet, or any other suitable thermoplastic material. More specifically, the thermoplastic sheet  106  may be an RTL sheet using a polyeitherimide (PEI or Ultem) matrix with either an Aramid (Kevlar), carbon, glass fibers, or any combination thereof, in a thermoplastic sheet. In general, in presently preferred embodiments, the glass transition point of the thermoplastic (where the material begins to flow) should be greater than the upper thermal requirement of the application. The creep forming point of the thermoplastic (where the material begins to change shape with low forces over time) should be greater than the upper thermal requirement. For example, for ECS ducts in aircraft, the upper thermal requirement is approximately 185 degrees F. The thermoplastic should also have the chemical resistance to products used in the application. For example, ECS ducts in aircraft use pesticides or cleaners that can attack certain types of plastics. 
         [0025]      FIG. 2  is an isometric view of the first mold member  102  of the system  100  of  FIG. 1 . In this embodiment, the first mold member  102  includes a recessed portion  110 . Similarly,  FIG. 3  is an isometric view of the second mold member  104  of the system  100  of  FIG. 1 . The second mold member  104  has a protruding portion  112  that is adapted to engage with the recessed portion  110  of the first mold member  102  leaving room for the thermoplastic sheet  106  to be formed between mold members  102  and  104 . 
         [0026]    In operation, the thermoplastic sheet  106  is positioned between the first and second mold members  102 ,  104 . The actuator  108  is then employed to drive the second mold member  104  against the thermoplastic sheet  106 , forming the thermoplastic sheet  106  between the first and second mold members  102 ,  104 . The thermoplastic sheet  106  is then press formed into a first-stage workpiece  114 .  FIG. 4  is a top elevational view of the first-stage workpiece  114  formed using the system  100  of  FIG. 1 . The first-stage workpiece  114  may then be trimmed, forming a second-stage workpiece  116  that includes a “Y”-shaped half-body portion  118  and one or more flange portions  120 . 
         [0027]      FIG. 5  is an isometric view of an air distribution system  200  including a component  210  formed in accordance with another embodiment of the present disclosure. In this embodiment, the component  210  includes a pair of “Y”-shaped half-body portions  118  formed in accordance with the present disclosure as described above with reference to  FIGS. 1-4 . The “Y”-shaped half-body portions  118  that might be the same, opposite, or unique beyond the common bond flange, are bonded together in any suitable manner to form the component  210 , as described more fully below. In addition, the component  210  is coupled a cylindrical supply tube  212  and to a pair of elbow tubes  214 . The air distribution system  200  may be used in a wide variety of applications, including for example, in a fresh-air distribution system of a commercial aircraft. 
         [0028]    Embodiments of apparatus and methods in accordance with the present disclosure may provide significant advantages over the prior art. Because components having unusual or complex curvature may be formed by press-molding a sheet of thermoplastic material between first and second mold members to form first and second half-body portions, and then coupling the first and second half-body portions together to form the desired component, the need to create relatively complex plaster mandrels and to perform labor-intensive layup processes is reduced or eliminated. Thus, the time and expense associated with forming components having unusual or complex curvature may be reduced in comparison with the prior art methods. Similarly, the cost of fabricating structures that include such complex components, such as aircraft, can also be reduced. 
         [0029]    It will be appreciated that the disclosure is not limited to the particular embodiments described above and shown in  FIGS. 1-5 , and that a variety of alternate embodiments may be conceived without departing from the spirit and scope of the disclosure. For example, the actuator  108  may be coupled to the second mold a member  104  rather than the first mold member  102 , or additional actuators may be added, or the actuator may even be eliminated and the process performed manually. Further, the recessed portion  110  and a protruding portion  112  may have a variety of different shapes adapted to form a variety of different thermoplastic components, and are not limited to the particular embodiments described above and shown in the accompanying figures. Thus, embodiments of the present disclosure include one or more components formed by press-forming thermoplastic material between two or more tools that define the pre-join shape of the component to other components that may have the same shape, opposite shape, or totally unique shape that has a common and opposite shaped flange. 
         [0030]    For example,  FIG. 6  is an isometric view of a pair of component portions  300 ,  302  formed in accordance with an alternate embodiment of the present disclosure. In this embodiment, the component portions  300 ,  302  are identical elbow-shaped half-body portions that may be coupled together to form an elbow-shaped duct  310  ( FIG. 7 ). Each of the component portions  300 ,  302  includes an inner flange portion  304  and an outer flange portion  306 . The inner flange portions  304 A,  304 B may be bonded together, and the outer flange portions  306 A,  306 B may be bonded together, thereby forming the elbow-shaped duct  310 . 
         [0031]    There are a number of ways in which the flange portions of the half-body portions of the clamshell can be made. For example, the flange can be perpendicular to the duct body, angled to the duct body or made to overlap within the duct body. Of course, other alternatives also exist. 
         [0032]    There are also a number of ways in which the flange portions of the half-body portions of a clamshell component may be coupled together in accordance with various alternate embodiments of the present disclosure. For example,  FIG. 8  is a partially-exploded, isometric view of a pair of component portions  320 ,  322  formed in accordance with another embodiment of the present disclosure. In this embodiment, the first portion  320  includes first and second flanges  324 ,  326 . The first flange  324  includes a first index member  332 , and the second flange  326  includes a first index recess  334 . Similarly, the second portion  322  includes a third flange  328  having a second index recess  336 , and a fourth flange  330  having a second index member  338 . An adhesive strip  340  is disposed on each of the first and second flanges  324 ,  326 . In operation, the first and second portions  320 ,  322  may be positioned with the first and third flanges  324 ,  328  positioned proximate to each other and the second and fourth flanges  326 ,  330  positioned proximate to each other. As the flanges are brought into contact, the first index member  332  is engaged into the second index recess  336 , and the second index member  338  is engaged into the first index recess  334 . In this way, the index members  332 ,  338  and the index recesses  334 ,  336  ensure that the first and second portions  320 ,  322  are properly positioned for bonding. The adhesive strips  340  secure the first and second portions  320 ,  322  together to form the resulting clamshell component. In one embodiment, the adhesive strip includes a composite grade adhesive. 
         [0033]    In an alternate embodiment, the flanges of the first and second portions  320 ,  322  may be bonded by a combination of heat and pressure. For example,  FIG. 9  is an isometric view of the first and second portions  320 ,  322  of  FIG. 8  being coupled together in accordance with another embodiment of the present disclosure. In this embodiment, a pair of heated cams  350 ,  352  are engaged against the first and third flanges  324 ,  328 , respectively. In operation, the flanges  324 ,  328  are pinched between the heated cams  350 ,  352  as the cams are translated along the length of the flanges  324 ,  328 . A similar bonding process can be performed on the second and fourth flanges  326 ,  330 . 
         [0034]    During the translation of the heated cams  350 ,  352  along the flanges, the heated cams  350 ,  352  elevate the flanges above a glass transition temperature of the thermoplastic materials of the flange, thereby allowing the flanges to consolidate and bond. Following the heating, pressure may be maintained on the heated portion of the flanges by a follower mechanism (e.g. shoes, wheels, etc.) until the temperature of the joint is below the glass transition temperature. The heated cams  350 ,  352  may be used in conjunction with an adhesive material ( FIG. 8 ), such as an adhesive thermoplastic tape, to increase the amount of matrix material in the bond area. The headed cams and follower mechanism can be flat or have a shape that helps change the shape and thus the shear characteristics of the flange. For example, a hump, ridge, or more radical shapes such as a crimp can be employed, as described more fully below. 
         [0035]      FIG. 10  is an isometric view of a bonding apparatus  400  for bonding a pair of thermoplastic clamshell components together in accordance with another embodiment of the disclosure.  FIG. 11  is an enlarged, partial isometric view of the bonding apparatus  400  of  FIG. 10 . In this embodiment, the bonding apparatus  400  includes first and second heated cams  402 ,  404 . The heated cams  402 ,  404  are operatively coupled to a drive motor  406  and to a heat source  408 . A control panel  410  is coupled to the drive motor  406  and the heat source  408 . The control panel  410  enables an operator (not shown) to control the temperature, pressure, and drive speed of the heated cams  402 ,  404 . As best shown in  FIG. 11 , a preheater  412  is positioned proximate the cams  402 ,  404 . In operation, the preheater  412  engages against the flanges as they are being fed into the heated cams. The preheater  412  preheats the flanges prior to being fully heated and pinched by the heated cams  402 ,  404 , thereby improving the quality of the bond. 
         [0036]      FIG. 12  is an isometric view of the first and second components  320 ,  322  being coupled together in accordance with a further embodiment of the present disclosure. In this embodiment, a crimping tool  450  is translated along the flanges  324 ,  328 , bending or crimping the flanges into a crimped portion  452 . In the embodiment shown in  FIG. 12 , the crimped portion  452  is an approximately right-angled portion, however, in alternate embodiments, other cross-sectional shapes of crimped portions may be used. More specifically, the crimp can be just over 0 degrees (obtuse fold) and approach 180 degrees (acute fold). The crimping tool  450  is similar to the heated cams described above, and can apply heat and pressure as described above, except that the crimping tool  450  also puts a crimp in the flanges. This is done to increase the seam strength of the joint, thereby providing a suitable bond that couples the first and second components  320 ,  322  together. 
         [0037]      FIG. 13  is a partially exploded isometric view of the first and second components  320 ,  322  being coupled together in accordance with a further embodiment of the present disclosure.  FIG. 14  is an isometric view of the first and second components  320 ,  322  of  FIG. 13  in a coupled position. In this embodiment, a sealant (or adhesive) material  550  is disposed between the flanges. As noted above, in one particular embodiment, the sealant is a composite grade adhesive. The sealant can be brushed on, applied from a tube or other container, applied in roll form, or may be applied using any other suitable application method. The sealant can be room or oven cured. As further shown in  FIG. 14 , one or more clips  552  may be used to lock the first and second components  320 ,  322  together. In alternate embodiments, other fastening devices may be used instead of or in addition to the clips  552 , including, for example, rivets or other types of fasteners. 
         [0038]      FIG. 15  is an isometric view of the first and second components  320 ,  322  of  FIG. 13  in a coupled position in accordance with yet another embodiment of the disclosure. In this embodiment, a welding device  650  is applied to the flanges. The welding device  650  includes a pair of external rollers  652  applied along opposing sides of the flanges, and an internal roller  654 . The welding device  650  is translated along the flanges, applying elevated temperature and pressure to the flanges, forming a weld bond. More specifically, the welding device  650  adds material to the joint by liquefying a primary material matrix of the thermoplastic material (e.g., Ultem/PEI, PPS, Nylon or other thermoplastic matrix) into the joint which is also heated so the added material becomes one with the joint, just as a metallic weld is formed when metal is added to a seam of the metallic weld. In one particular embodiment, the materials can be added in a tape form and then melted into the seam, or alternately, it can be melted in a gun and extruded into the seam. The material can also be applied perpendicular to the joint or between the flanges and joined using the same tools used to crimp or consolidate as described above. 
         [0039]    While preferred and alternate embodiments of the disclosure have been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the disclosure. Accordingly, the scope of the disclosure is not limited by the disclosure of the preferred and alternate embodiments. Instead, the disclosure should be determined entirely by reference to the claims that follow.