Abstract:
Systems and methods are provided for controlling flexible tracks. One embodiment is a system for conveying plies of laminate to a forming device. The system includes a flexible track assembly comprising a first portion of track and a second portion of track, each of the portions defining a groove dimensioned to receive a slider that transports a ply, the second portion arranged to transport the ply into the forming device. The track assembly also includes a guide in which ends of the portions are disposed. The system further includes a retraction line that applies a contracting force that biases the end of the second portion towards contact with the end of the first portion, the retraction line being extendable to enable the second portion to separate from the first portion, thereby accommodating extension of the track assembly in response to forces applied by the forming device during forming.

Description:
FIELD 
     The disclosure relates to the field of fabrication, and in particular, to forming curable composite materials. 
     BACKGROUND 
     The fabrication of cured composite parts remains an involved process. Layers of constituent material (e.g., Carbon Fiber Reinforced Polymer (CFRP)) for a part may be laid-up one after another onto a surface and formed into a laminate having a complex shape. The laminate may then be cured (e.g., via the application of heat) into a unified, integral composite part having enhanced structural properties. Forming a laminate into a complex desired shape is particularly complicated, as this involves applying forces to the laminate from a variety of angles to apply stress to the laminate while also preventing the laminate from tearing. 
     Because the processes involved in forming a laminate are complex and time-consuming, it remains desirable to enhance the speed and efficiency with which laminates are formed and prepared for forming. Thus, operators of forming devices continue to seek out enhanced systems and techniques for performing the forming process efficiently. 
     SUMMARY 
     Embodiments described herein enhance tracks used for delivering laminates of constituent material to a forming device. Specifically, embodiments described herein utilize the insight that a forming device will apply forces to the track when forming the laminate into a desired shape, and implement systems that enable the track to deflect, reposition, rotate, pivot, and/or extend in response to forces applied by the forming device. When the forming device has completed forming of a laminate into a desired shape, the systems described herein may return the track to a resting position that the track occupied before the forming device began forming. This enables another slider of laminate to be efficiently delivered to the forming device. The features described herein also may facilitate the process of manually moving a laminate towards/into a forming device, by ensuring that the track may be deflected and/or extended without substantial effort by a user. 
     One embodiment is a system for conveying plies of laminate to a forming device. The system includes a flexible track assembly comprising a first portion of track and a second portion of track, each of the portions defining a groove dimensioned to receive a slider that transports a ply, the second portion arranged to transport the ply into the forming device. The track assembly also includes a guide in which an end of the first portion and an end of the second portion are disposed. The system further includes a retraction line that applies a contracting force that biases the end of the second portion towards contact with the end of the first portion, the retraction line being extendable to enable the second portion to separate from the first portion by sliding within the guide, thereby accommodating extension of the track assembly in response to forces applied by the forming device during forming. 
     Another embodiment is a method for controlling a position of a flexible track assembly that conveys plies of laminate to a forming device. The method includes positioning an end of a first portion of track and an end of a second portion of track within a guide, applying a contracting force via a retraction line that biases the end of the first portion towards contact with the end of the second portion and extending the retraction line in response to the contracting force being overcome by another force applied by the forming device during forming, causing the end of the second portion to separate from the end of the first portion and slide within the guide. The method further includes retracting the retraction line, thereby drawing the second portion towards the first portion in response to the other force terminating. 
     Other exemplary embodiments (e.g., methods and computer-readable media relating to the foregoing embodiments) may be described below. The features, functions, and advantages that have been discussed 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. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Some embodiments of the present disclosure are now described, by way of example only, and with reference to the accompanying drawings. The same reference number represents the same element or the same type of element on all drawings. 
         FIG. 1  is a diagram of a laminate delivery system for transporting laminates to a forming device in an exemplary embodiment. 
         FIGS. 2-4  are diagrams of a slider mounted to a track assembly of a laminate delivery system in an exemplary embodiment. 
         FIG. 5  is a diagram illustrating systems that enable dynamic and temporary deflection and extension of a track of a laminate delivery system in an exemplary embodiment. 
         FIGS. 6-7  are diagrams illustrating extension of a track of a laminate delivery system in an exemplary embodiment. 
         FIGS. 8-10  are diagrams illustrating deflection of a track assembly of a laminate delivery system in an exemplary embodiment. 
         FIG. 11  is a flowchart illustrating a method for utilizing a track assembly of a laminate delivery system in an exemplary embodiment. 
         FIG. 12  is a block diagram of a laminate delivery system in an exemplary embodiment. 
         FIG. 13  is a flow diagram of aircraft production and service methodology in an exemplary embodiment. 
         FIG. 14  is a block diagram of an aircraft in an exemplary embodiment. 
     
    
    
     DESCRIPTION 
     The figures and the following description illustrate specific exemplary embodiments of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the disclosure and are included within the scope of the disclosure. Furthermore, any examples described herein are intended to aid in understanding the principles of the disclosure, and are to be construed as being without limitation to such specifically recited examples and conditions. As a result, the disclosure is not limited to the specific embodiments or examples described below, but by the claims and their equivalents. 
       FIG. 1  is a diagram of a laminate delivery system  100  for transporting laminates to forming device  140  in an exemplary embodiment. According to  FIG. 1 , forming device  140  dynamically operates upon a laminate borne by slider  200  in order to form the laminate into a desired shape for curing. Track assembly  110  is utilized to deliver/convey slider  200  to forming device  140 . In this embodiment, track assembly  110  is a flexible structure comprising a material capable of bending and/or elastically deflecting in response to forces applied by forming device  140 . For example, while operating upon a laminate at slider  200 , forming device  140  may apply forces to track assembly  110  that result in deformation of track assembly  110 . If track assembly  110  remains bound in place while forming device  140  operates, track assembly  110  may experience stress and strain that results in degradation and/or failure. Conversely, if track assembly  110  is not adequately supported, the lack of rigidity in track assembly  110  will make it more difficult to transport slider  200  along track assembly  110  towards forming device  140 . 
     In order to ensure that track assembly  110  is held in position to allow slider  200  to slide easily towards forming device  140 , and in order to also enable track assembly  110  to deflect and/or extend in accordance with the operations of forming device  140 , retractor system  160  (comprising retractors  162  and  164 ) is utilized. Retractor system  160  enhances the ability of track assembly  110  (and/or components thereof) to dynamically extend/deflect in response to forces applied by forming device  140 , and without damaging track assembly  110 . When forces applied by forming device  140  stop, retractors  162  and  164  return track assembly  110  to a desired default position. Thus, track assembly  110  maintains a desired shape for transporting slider  200 , but also moves in accordance with forming device  140 . 
     In this embodiment, track assembly  110  is fixedly attached to support  120 , while retractors  162  and  164  are located proximate to support  130 . An additional track assembly  150  is included proximate to forming device  140  to ensure adequate support of slider  200  as slider  200  travels towards forming device  140 . However, any suitable combination of supports, retractors, and/or track assemblies may be utilized in order to convey a laminate to forming device  140  in a desired manner (e.g., in order to conform with the arrangement of machinery on a factory floor). 
       FIGS. 2-4  are diagrams of a slider  200  mounted to a track assembly  110  of a laminate delivery system  100  in an exemplary embodiment. In particular,  FIG. 2  is a view of section  2  of  FIG. 1 ,  FIG. 3  is a diagram illustrated by view arrows  3  of  FIG. 2 , and  FIG. 4  is a view of section  4  of  FIG. 3 . Slider  200  travels across track assembly  110  from an initial starting point shown in  FIG. 1  towards forming device  140  in order to deliver a ply of laminate for forming. In this embodiment, slider  200  includes flexible substrate  210  (e.g., a fabric, such as a woven combination of rubber and thread) and laminate  220  (e.g., uncured CFRP) which is attached to fabric  210 . Laminate  220  may comprise any suitable shape capable of coupling with substrate  210  and being formed by forming device  140 . Laminate  220  will be formed by forming device  140 , and then cured into a composite part utilized for example as a component of an aircraft. Slider  200  further includes region  230  which include mating features  240 . As shown in  FIG. 3 , each mating feature  240  includes one or more projecting elements  242 , and securement element  244  which sits secured within a groove defined by track assembly  110 , and is dimensioned to slide within the groove. Slider  200  also includes region  250 , which may for example comprise a continuous extrusion for insertion into additional track assembly  150 . 
       FIG. 4  illustrates a further detailed view of a mating feature  240  mated with track assembly  110 . Specifically,  FIG. 4  illustrates that track assembly  110  includes a segment of track  112 , and also includes a guide/backbone  114 . Track  112  defines groove  111  through which mating features  240  slide, and further includes projections  112  and flanges  113 . Meanwhile, guide  114  includes flanges  116 , which define groove  115  through which track  112  may slide. That is, individual segments of track  112  may be slidably mated (i.e., slip fit) with guide  114 , or may be fixedly attached to guide  114  as desired. In embodiments where track  112  is fixedly attached to guide  114 , fixation elements  118  (e.g., screws, bolts, rivets, glue, etc.) may be utilized to affix track  112  to guide  114 . 
     With the structure of track assembly  110  and slider  200  now understood, the arrangement of track assembly  110  with respect to forming device  140  will now be discussed.  FIG. 5  is a diagram illustrating systems that enable dynamic and temporary deflection and extension of a track of a laminate delivery system in an exemplary embodiment.  FIG. 5  is a top-down view indicated by view arrows  5  of  FIG. 1 . As shown in  FIG. 5 , track assembly  110  includes a first portion of track  112  (P 1 ), and a second portion of track  112  (P 2 ). The first portion of track  112  may be fixed to a corresponding portion of guide  114 , while the second portion of track  112  may be slidably supported by guide  114 . In this manner, when forming device  140  applies forces to track assembly  110  during forming, portion P 2  may travel (e.g., in a direction corresponding to force F) with respect to portion P 1 . As shown in  FIG. 5 , portion P 1  may be fixedly attached to support  120  at location  500  (e.g., via fixed attachment to guide  114 , which itself is fixed to support  120 ). Meanwhile, portion P 2  may be movably attached to support  130 , which enables portion P 2  to deflect/translate by some amount A in response to forces applied by forming device  140 . The ability to move portion P 2  is also advantageous because it reduces the amount of effort required for a user to convey slider  200  along P 2  to forming device  140 . 
       FIG. 5  further illustrates retractors  162  and  164 , which together enable portion P 2  to return to a desired default position (e.g., in contact with support  130 ) after forming device  140  stops applying forces to portion P 2 .  FIGS. 6-7  are diagrams illustrating extension and retraction of a track  112  of a laminate delivery system  100  in an exemplary embodiment. As shown in  FIG. 6 , support  610  (e.g., a clamp) is fixedly attached to a segment of track  112  at portion P 1 , while another support  610  is fixedly attached to guide  114  aligned with portion P 2  of track  112 . Retraction line  620  is attached to each of supports  610 . Segments of track  112  at portion P 1  are fixedly attached to guide  114 , while segments of track  112  at portion P 2  are slidably attached to guide  114 . In this arrangement, when forming device  140  applies a force F to portion P 2  (as shown in  FIG. 7 ), portion P 2  slides within guide  114  away from portion P 1  by a distance D. While track assembly  110  is extended in this manner, retraction lines  620  applies a contracting force (C) that draws an end  640  of portion P 2  back towards an end  630  of portion P 1 . 
       FIGS. 8-10  are diagrams illustrating deflection of a track assembly  110  of a laminate delivery system  100  in an exemplary embodiment. Specifically,  FIG. 8  is a view indicated by view arrows  8  of  FIG. 5 . As shown in  FIG. 8 , retractor  164  includes spring-loaded cable reel  810 , to which cable  812  (e.g., a metal cable) is fixedly attached. Thus, cable  812  is fixedly attached to support  130  via cable reel  810 . Cable  812  travels through fairing hole  822  (i.e., an opening) of block  820  as cable  812  extends and retracts, and cable  812  is fixedly attached to guide  114  via fixation elements  830  and  840 . In this embodiment, fairing hole  820  has a circular cross section, although in further embodiments fairing hole  820  may define a rectangular slot or other geometry.  FIG. 9 , indicated by view arrows  9  of  FIG. 8 , further illustrates fixation elements  830  (in this case, a bolt driven through guide  114  having a head  832 ), and  840  (in this case, a metal loop hooked around fixation element  830 ). When at rest, cable  812  applies a resting force R that holds/biases guide  114  towards contact with/proximate to support  130 . 
     In  FIG. 10 , indicated by view arrows  6  of  FIG. 5 , during normal operations forming device  140  may apply a changing and dynamic force that overcomes the resting force provided by cable  812 , which in turn results in guide  114  traveling a distance D z . The distance may also include a vertical component D y  (not shown) and/or a rotary component (also not shown). When forming device  140  completes operation, the resting force applied by cable  812  draws guide  114  back to support  130 , ensuring that track assembly  110  returns to a desired default position (e.g., as shown in  FIG. 8 ). 
     In further embodiments, retractor  162  of  FIG. 6  may utilize a line that applies force via a spring-powered line/cable reel system similar to that used by retractor  164 . Similarly, retractor  164  may utilize a cable that comprises an elastic cord similar to that shown for retractor  162 . 
     Illustrative details of the operation of laminate delivery system  100  will be discussed with regard to  FIG. 11 . Assume, for this embodiment, that slider  200  has been placed into track assembly  110  as shown in  FIG. 1 . Further, assume that a user or automated mechanism has drawn slider  200  along track assembly  110  to an entrance of forming device  140 . Forming device  140  utilizes mating features  240  as an indexing mechanism to ensure that laminate  220  is accurately formed, and is about to start forming operations to laminate  220  that will in turn apply forces that deflect and/or extend track assembly  110 . 
       FIG. 11  is a flowchart illustrating a method  1100  for utilizing track assembly  110  of laminate delivery system  100  in an exemplary embodiment. The steps of method  1100  are described with reference to laminate delivery system  100  of  FIG. 1 , but those skilled in the art will appreciate that method  1100  may be performed in other systems. The steps of the flowcharts described herein are not all inclusive and may include other steps not shown. The steps described herein may also be performed in an alternative order. 
     Before slider  200  has reached support  130 , retractors  162  and  164  position/hold end  630  of portion P 1  of track  112 , and end  640  of portion P 2  of track  112 , within guide  114  at a location that is proximate to support  130  (step  1102 ). Retractor  162  applies a contracting force via retraction line  620  that biases the end of portion P 1  towards contact with the end of portion P 2  (step  1104 ), and retractor  164  supplies a resting force to draw guide  114  proximate to support  130 . Thus, at this point in time, track assembly  110  is in a resting position that enables slider  200  to slide into forming device  140 . 
     Slider  200  may slide across portions P 1  and P 2  of track assembly  110  in order to deliver laminate  220  to forming device  140 . After slider  200  has entered forming device  140 , forming device  140  may then begin operations. This applies a dynamic and changing force (e.g., an unpredictable force) to track assembly  110  that may vary over time, drawing track assembly  110  in a variety of directions at a variety of magnitudes of force. As the operations of forming device  140  continue, retraction line  620  extends in response to the contracting force being overcome by another force applied by forming device  140  during forming. This in turn causes end  640  of portion P 2  to separate from end  630  of portion P 1 , making portion P 2  slide within guide  114  as illustrated in  FIG. 7  (step  1106 ). Depending on the orientation of the force applied by forming device  140 , this may also overcome a resting force applied by cable  812  to guide  114 , resulting in guide  114  displacing/deflecting from support  130 . Eventually, the amount of force applied by forming device  140  will terminate or otherwise be overcome by the resting and contracting forces. Thus, retraction line  620  contracts, drawing portion P 2  of track  112  towards portion P 1  in response to the force applied by forming device  140  terminating (step  1108 ). 
     Utilizing the methods and techniques described herein, sliders  200  moving across a track assembly  110  may be fully supported during their travels. Furthermore, the exact position of a portion of track assembly  110  may be altered in a varying manner (e.g., in order to respond to forces applied by forming device  140  as forming device  140  creates different shapes) without damaging track assembly  110 . This provides a substantial benefit because it prevents forming device  140  from damaging track assembly  110 . Furthermore, in environments where the motion of individual sliders is not automatic but rather is manually performed by an operator, the systems described herein ensure that the operator is not required to utilize a substantial amount of force in order to adjust the position of track assembly  110  as desired to ensure that laminates are properly loaded into forming device  140  (e.g., in order to pull a slider  200  into forming device  140 , or to perform any other suitable task). 
     EXAMPLES 
     In the following examples, additional processes, systems, and methods are described in the context of a laminate delivery system. 
       FIG. 12  is a block diagram of a laminate delivery system  1200  in an exemplary embodiment. In this example, system  1200  includes retractor  1210 , retractor  1220 , and forming device  1230 . Retractor  1210  includes supports  1212 , to which retraction line  1214  is attached. Retractor  1210  controls for extension of track assembly  1240 . Meanwhile, retractor  1220  includes spring reel  1222 , which applies a resting force to cable  1224 . Cable  1224  travels through fairing hole  1226  of block  1228 , and attaches to guide  1250  of track assembly  1240 . Retractor  1220  compensates for deflection of track assembly  1240 . 
     Track assembly  1240  includes guide  1250 , which includes groove  1252  for accepting segments  1262  of track  1260 . Guide  1250  further includes fixation elements  1254 , which may be utilized to fix segments  1262  of track with respect to guide  1250 . Track  1260  includes portions  1261  (e.g., portions which are fixedly attached to, or slidably disposed within, guide  1250 ). Each portion  1261  includes one or more segments  1262 . Each segment  1262  includes one or more projections  1263  and flanges  1264  that together define a groove  1265  for receiving slider  1270 . Slider  1270  includes multiple mating features  1271 , which each include a projection  1272  and securement element  1273 . Substrate  1274  is attached to one or more mating features  1271 , and laminate  1275  is attached to substrate  1274 . Laminate  1275  may be delivered to forming device  1230  by moving slider  1270  along track  1260 . 
     Referring more particularly to the drawings, embodiments of the disclosure may be described in the context of an aircraft manufacturing and service method  1300  as shown in  FIG. 13  and an aircraft  1302  as shown in  FIG. 14 . During pre-production, exemplary method  1300  may include specification and design  1304  of the aircraft  1302  and material procurement  1306 . During production, component and subassembly manufacturing  1308  and system integration  1310  of the aircraft  1302  takes place. Thereafter, the aircraft  1302  may go through certification and delivery  1312  in order to be placed in service  1314 . While in service by a customer, the aircraft  1302  is scheduled for routine maintenance and service  1316  (which may also include modification, reconfiguration, refurbishment, and so on). 
     Each of the processes of method  1300  may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on. 
     As shown in  FIG. 14 , the aircraft  1302  produced by exemplary method  1300  may include an airframe  1318  with a plurality of systems  1320  and an interior  1322 . Examples of high-level systems  1320  include one or more of a propulsion system  1324 , an electrical system  1326 , a hydraulic system  1328 , and an environmental system  1330 . Any number of other systems may be included. Although an aerospace example is shown, the principles of the invention may be applied to other industries, such as the automotive industry. 
     Apparatus and methods embodied herein may be employed during any one or more of the stages of the production and service method  1300 . For example, components or subassemblies corresponding to production stage  1308  may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft  1302  is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the production stages  1308  and  1310 , for example, by substantially expediting assembly of or reducing the cost of an aircraft  1302 . Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while the aircraft  1302  is in service, for example and without limitation, to maintenance and service  1316 . For example, the techniques and systems described herein may be used for steps  1306 ,  1308 ,  1310 ,  1314 , and/or  1316 , and/or may be used for airframe  1318  and/or interior  1322 . These techniques and systems may even be utilized for systems  1320 , including for example propulsion  13   24 , electrical  1326 , hydraulic  1328 , and/or environmental  1330 . 
     In one embodiment, laminate delivery system  100  is utilized to fabricate composite parts that comprise a portion of airframe  118 , which are manufactured during component and subassembly manufacturing  1108 . These composite parts may then be assembled into an aircraft in system integration  1110 , and then be utilized in service  1114  until wear renders a composite part unusable. Then, in maintenance and service  1116 , a composite part may be replaced with a newly manufactured composite part. Retractors  162  and/or  164  may be utilized throughout the process to ensure that laminates are formed for these new composite parts in a manner that is both efficient and reliable. 
     Although specific embodiments are described herein, the scope of the disclosure is not limited to those specific embodiments. The scope of the disclosure is defined by the following claims and any equivalents thereof.