Abstract:
A method of operating a production line comprises the steps of supporting equipment in the production line on a plurality of crawlers comprising at least one rolling track and a structural support for supporting the equipment. A first plurality of lifting magnets coupled to an interior surface of said at least one rolling track is configured to oppose a second plurality of lifting magnets coupled to an exterior surface of said structure support to lift the structural support, such that the structural support floats between and within said at least one rolling track. The magnetic fields experienced by the first and second plurality of lift magnets are adjusted to translate the at least one rolling track, such that the crawlers move along the production line.

Description:
RELATED APPLICATION 
     This application is a divisional application of, and claims priority from, pending prior application Ser. No. 10/904,710, filed Nov. 24, 2004. 
    
    
     TECHNICAL FIELD 
     This application relates generally to aeronautical vehicle manufacturing systems and, more particularly, to a system and method for adjusting the location of a moving production line and for providing easy access to vehicle components on that production line. 
     BACKGROUND 
     Traditionally, aircraft have been manufactured in a single stationary location. During the manufacturing or “build-up” of the aircraft, components and systems are brought to a designated location in which the fuselage of the aircraft is stationed. Due to a desire to increase the efficiency of aircraft production, to minimize congestion of systems and components in a single location, and to minimize the amount of inventory existing at any one time within a facility, some aircraft are now being manufactured through the use of a moving production line. 
     A moving production line allows a fuselage to be transitioned from station to station where components and systems are installed. At each station a designated set of tasks are performed. Respective components and systems are delivered to and located near the appropriate station where they are to be installed onto the fuselage. Thus, each station has a minimal amount of associated inventory. Also, each station has a minimal amount of equipment and personal to perform the designated tasks for that station. Thus, there is less congestion in any single location and improved efficiency. 
     A desire exists for the ability to change the location of a moving production line from one location to another in a short period of time. Although a moving production line provides the above-stated advantages, a moving production line is limited in mobility and flexibility. In general, a moving production line consists of a rail system that is fixed to a plant facility floor. Multiple carriers, carrying various aircraft components and sub-assemblies, such as the aircraft fuselage, are pulled via chain from station to station. The rail system is stationary and thus cannot be moved to a different location without a considerable amount of time and expense in dismantling, transporting, and rebuilding the rail system. Also, the carriers are locked in a particular order and cannot easily be altered or relocated. 
     In addition, a desire also exists for an aircraft under production or components thereof to be positioned close to the floor of a production facility for ease of manufacturing. Low positioning, for example, of a fuselage allows personal to walk directly onto the fuselage without use of ladders or other lifting or escalating devices. Current rail systems fail to provide such positioning. 
     Thus, there exists a need for an improved moving production line system that allows for the repositioning of a moving production line and that allows for systems and components of an aircraft to be in low easy to access vertical positions during manufacturing and assembly of that aircraft. 
     SUMMARY 
     The disclosure provides an equipment-carrying crawler that includes a rolling track and a structural support. The structural support supports equipment. Lifting magnets are coupled to the rolling track and to the structural support. The lifting magnets are configured to oppose each other, lift the structural support, and aid in translation of the rolling track. 
     The disclosure provide several advantages. One such advantage is the provision of a production line crawler that is capable of supporting vehicle components within a production line, as well as being translocated. The utilization of the crawler allows for the translation of vehicle components along a production line in addition to the ability of moving or changing the location of the production line within a manufacturing facility. 
     Another advantage provided by the disclosure is the provision of a production line cradle system in which aircraft components may be translated along a production line at a vertical level that provides easy access thereof for efficient performance of manufacturing tasks. 
     Furthermore, a simple compact passive system is provided for lifting and transporting vehicle components from station to station in a production line. 
     The disclosure itself, together with further objects and attendant advantages, will be best understood by reference to the following detailed description, taken in conjunction with the accompanying drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a production line in accordance with one embodiment; 
         FIG. 2  is a perspective view of a production line cradle system in accordance with one embodiment; 
         FIG. 3  is a perspective view of a production line crawler in accordance with one embodiment; 
         FIG. 4  is a cross-sectional view of the production line crawler of  FIG. 3 ; 
         FIG. 5  is a block diagrammatic view of a crawler control system in accordance with one embodiment; 
         FIG. 6  is a logic flow diagram illustrating a method of operating a production line in accordance with one embodiment; and 
         FIG. 7  is a logic flow diagram illustrating a method of manufacturing an aircraft in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In each of the following Figures, the same reference numerals are used to refer to the same components. While the disclosure is described with respect to a system for adjusting the location of a moving production line and for providing easy access to vehicle components on that production line, the principles of the disclosure may be adapted for various applications and systems, such as production line applications, the transfer of a vehicle, vehicle components, equipment, or machinery between locations, or other applications and systems known in the art. The systems and methods may be applied to both aeronautical and non-aeronautical systems and components. 
     The systems and methods disclosed may be utilized to move satellites, munitions, optical equipment, equipment containing chemical and biological agents, general-purpose cleaning equipment, and various other equipment. The munitions may be chemical, biological, nuclear, or conventional. The disclosure may, for example, be used to transport or hold a telescope assembly used in a laboratory test, or it may be used to move and to hold heavy equipment stable during precise assembly steps, or it may also be used to move equipment into laboratories, factories, and cleaning rooms, or to carry equipment to remote locations. 
     In the following description, various operating parameters and components are described for one constructed embodiment. These specific parameters and components are included as examples and are not meant to be limiting. 
     Referring now to  FIG. 1 , a perspective view of a production line  10  is shown within a manufacturing facility  12 . The production line  10  transitions or moves multiple production line cradle systems  14  carrying equipment or vehicle components  16 , such as aircraft fuselages, as shown, to various manufacturing stations  18 . The term “equipment” may refer to a single component or to multiple components. The vehicle components  16  are carried along the production line  10  from station to station. At each station  18  a pre-assigned set of manufacturing tasks are performed. The cradle systems  14  include multiple equipment or production line crawlers  20 , which are able to travel along the production line  10 . The use of the crawlers  20  also allows the production line  10  to be translocated to different locations. The production line  10  is not rigidly fixed to the floor  22  of the facility  12 , like that of a traditional production line track system. 
     In the production line  10  the vehicle components or fuselages  16  are being carried by the cradle systems  14 . Each fuselage  16  is supported by two cradle systems. A first cradle system  24  supports a front portion  26  of the fuselages  16  and a second cradle system  28  supports a rear portion  30  of the fuselages  16 . Although two cradle systems are utilized and are shown in a single arrangement, any number of cradle systems may be utilized in various arrangements. The crawlers may be used to carry equipment within a production line as shown or may be used to carry equipment in various other applications, some of which are mentioned above. The crawlers may be of various sizes to accommodate the various applications. 
     The crawlers  20  may be setup and associated with various stations along the production line  10 . Each crawler  20  may have station associated tooling and equipment required to perform predetermined tasks for that station. Since the crawlers  20  are mobile they may be positioned in different orders and assigned to different stations. In addition, when maintenance is to be performed on a particular crawler it may be easily replaced with a similar crawler for minimum production line down time. 
     Referring now to  FIG. 2 , a perspective view of the production line cradle system  14  is shown. The cradle system  14  includes a pair of the production line crawlers  20  and a cradle  40  that spans between the crawlers  20 . The cradle  40  supports one or more vehicle components and systems. The cradle  40  is coupled to the crawlers  20  via straddle support members  42 . The cradle  40  may hang over the tracks  44  of the crawlers  20 , as shown, in a lateral configuration or may hang between the crawlers  20  in a fore/aft configuration (not shown). The cradle  40  includes a first member  46  that is coupled to a first support member  48  of a first crawler  50 . The cradle  40  also includes a second member  52  that is coupled to a second support member  54  of a second crawler  56 . A “U-shaped” element  58  is coupled between the members  46  and  52 . The U-shaped element  58  has similar shape as that of the exterior of an aircraft fuselage for proper support of the fuselage by the cradle  40 . 
     Although the support members  42  are shown as being in the form of single shafts supporting the cradle  40 , they may be in the form of multiple shafts or supporting members and have any number of attachment points. The support members  42  may also be in various arrangements known in the art. 
     The lower portion  60  of the U-shaped element  58  hangs below the top surfaces  62  and  64  of the rolling tracks  44  and below the upper platforms  66  of the crawlers  20 , respectively. This low hanging orientation of the U-shaped element  58  provides easy access to vehicle components residing on the cradle  40 . 
     Referring now to  FIGS. 3 and 4 , a perspective view and a cross-sectional view of the production line crawler  20  are shown. The crawler  20  includes a pair of the rolling tracks  44 , a strongback or structural support  70 , and multiple lift magnets  72  that are coupled therebetween and provide lift to the structural support  70 . The structural support  70  in essence floats between and within the rolling tracks  20  via the lift magnets  72 . 
     The structural support  70  includes the upper platform  66  and the lower platform  76  coupled via spacers  78 . A first pair of magnet mounting plates  80  is coupled to the upper surface  64 . A second pair of magnet mounting plates  82  is coupled to the lower surface  84  of the lower platform  76 . The vertical support member  42  is coupled to the upper platform  66  and may be coupled to one or more vehicle components or to a cradle, as shown in  FIG. 2 . 
     Each rolling track  44  includes a series of treads  90  that are linked to each other in a continuous format. Each tread  90  is translated across and around an end of the structural support  70 . A first rolling track  92  translates around a first end  94  of the structural support  70  and a second rolling track  96  translates around a second end  98  of the structural support  70 . Each rolling track  44  may be covered in rubber or similar material to protect travel surfaces and provide some energy absorption during travel from uneven surfaces. 
     The lift magnets  72  include a first set of lift magnets  100  that are coupled to the rolling tracks  44  and a second set of lift magnets  102  that are coupled to the structural support  70 . The first lift magnets  100  are directed at and have the same polarity as the second lift magnets  102 . The second lift magnets  102  include upper lift magnets  101  and lower lift magnets  103  that are mounted on the mounting plates  80  and  82 , respectfully. The upper lift magnets  101  are used to maintain separation between the tracks  44  and the structural support  70 . The upper lift magnets  101  or a portion thereof may attract the lift magnets  100  to the extent to which they provide stability in the track. The lower lift magnets  103  are used to lift the structural support  70 . The strength of the opposition between the lift magnets  72  correlates to the size of the floating lift gap  104  between the first lift magnets  100  and the lower lift magnets  103  and to the upper separation gap  105  between the first magnet  100  and the upper lift magnets  101 . Also, in general, a smaller gap  104  increases the amount of weight that can be lifted. As opposing magnets of the same polarity are brought together, the smaller the gap therebetween the greater the opposing force, which enables the lifting of an increased amount of weight. 
     The crawler  20  also includes multiple stability magnets  110  and superconducting devices  112 . The stability magnets  110  include a first set of stability magnets  114  and a second set of stability magnets  116 . The first stability magnets  114  are coupled on an outward end  118  of the rolling tracks  44 . The second stability magnets  116  are coupled on an inboard end  120  of the rolling tracks  44 . The first lift magnets  100  reside between the first stability magnets  114  and the second stability magnets  116 . The superconducting devices  112  reside within cryostats  122  on the lower magnet mounting plates  82 . The second lift magnets  102  reside between an outer cryostat  124  and an inner cryostat  126 . 
     In operation, the stability magnets  110  generate magnetic stability fields. The superconducting devices  112  react to the magnetic stability fields and generate current therein, which opposes changes in the stability fields as experienced by the superconducting devices  112 . In so doing, the superconducting devices  112  maintain position of the rolling tracks  44  relative to the structural support  70 . The stability magnets  110  may provide some lift, but are primarily utilized for stability of the structural support  70 . The lift magnets  72  provide a majority of the lift. 
     The crawler  20  includes a cooling circuit  130  for cooling the superconducting devices  112 . The superconducting devices  112  may be high temperature superconducting devices or low temperature superconducting devices. The superconducting devices  112  may be in the form of superconducting crystals or magnets. The cooler the superconducting devices  112  are maintained the stronger and more effective they are in preventing any shifting between the rolling tracks  44  and the platform  70 . 
     The cooling circuit  130  includes the chilling devices, such as the cryostats  122 , and may include various cryogenic devices or a cold head, as designated by items  132 . The cryostats  122  may be in the form of a liquid nitrogen or liquid helium cooling bath. When high temperature superconducting devices are utilized, the cooling bath contains liquid nitrogen that may be maintained at temperatures approximately between 60-80.degree. K. In one embodiment, the temperature of the liquid nitrogen bath is maintained at approximately 77.degree. K. The stated temperatures are for example purposes. Of course, the liquid nitrogen bath may be maintained at other known or desired temperatures. 
     Although cryostats and superconducting devices are shown as being coupled to the lower magnet mounting plates  82 , cryostats and superconducting devices may also be coupled to the upper magnet mounting plates  80  and used for further stability. 
     In addition, lateral arced plates  132 , as shown in  FIG. 4 , may be coupled to the platforms  66  and  76  and also include cryostats and superconducting devices mounted thereon for added stability. As well, additional lift magnets may also be coupled to the arced plates  132  and directed at the first lift magnets  100  to prevent slack in the rolling tracks  44 . 
     The above-stated lift magnets  72  and stability magnets  110  may be in the form of permanent magnets and generate magnetic fields naturally without the use of an external power source. In one embodiment, the lift magnets  72  are formed of Neodymium Iron Boron (NdFeB). The superconducting devices  112  are also not supplied power, but their reactance to a magnetic field depends upon the temperature in which they are maintained. In general, the superconducting devices  112  provide increased resistance to magnetic field change with a decrease in operating temperature. 
     Referring now also to  FIG. 5 , a block diagrammatic view of a remote crawler control system  150  is shown. The remote control system  150  includes multiple crawler control systems  152  and a remotely located control center  154 . The crawler control systems  152  may include drive motors  156 , various sensors  158 , and onboard controllers  160 . The drive motors  156  are utilized to translate the rolling tracks  44 . The sensors  158  are used to detect the status of the crawlers associated with the crawler control systems  152 , such as the crawler  20 , and components thereof. The onboard controllers  160  are coupled to the drive motors  156  and to the sensors  158  and adjust the speed, position, and temperature of the crawlers and/or components thereof in response to data received from the sensors  158 . The control center  154  includes a remote controller  162 , which is in communication with the onboard controllers  160  via the crawler transceivers  164  and the control center transceiver  166 . The control center  154  adjusts or changes the location of the crawlers as desired. 
     The drive motors  156 , as an example, may be in the form of induction motors. The drive motors  156  may be coupled to the upper platform  66  and generate drive magnetic fields, which react with the magnetic fields generated by the first lift magnets  100 . The drive magnetic fields change in polarity and magnitude to change the direction and speed of the rolling tracks  44 . The drive motors  156  may generate a drive magnetic field that either attracts or opposes the magnetic field generated by the lift magnets  100 , which causes motion of the rolling tracks  44  in the appropriate direction. Since there are no contact surfaces in the actual lifting portion of the crawlers  20 , in other words, since the structural support  70  is floating within the rolling tracks  44 , little energy is needed to drive the rolling tracks  44 . Thus, the drive motors  156  are small in size. 
     The sensors  158  may include speed sensors  170 , position sensors  172 , temperature sensors  174 , as well as other sensors known in the art for detecting the status of a crawler. The crawler  20  may have a speed sensor associated with each of the rolling tracks  44 . In a sample embodiment, the onboard controllers  160  adjusts the speed of the associated crawler along a production line in response to data generated from the speed sensors  170 . The onboard controllers  160  adjust the position of the crawlers, such as during the translocation of a production line, in response to the data generated by the position sensors  172 . The onboard controllers  160  adjust the temperature of cooling devices, such as the cryostats  122 , in response to the data received from the temperature sensors  174 . 
     The onboard controllers  160  and the remote controller  166  may be microprocessor based such as a computer having a central processing unit, memory (RAM and/or ROM), and associated input and output buses. The onboard controllers  160  may be a portion of a central vehicle main control unit, be divided into multiple controllers, or be a single stand-alone controller as shown. The remote controller  166  generates a translocate signal, which is transmitted to the onboard controllers  160  for translocating an associated production line. 
     Power supplies  176  also reside within the crawler control systems  152  and on the structural supports  70 . The power supplies  176  supply power to the drive motors  156  and to the onboard controllers  160 . The power supplies  176  may be of various types and styles known in the art. 
     Although the following methods of  FIGS. 6 and 7  are described primarily with respect to the production line  10  of  FIG. 1 , the crawlers  20  of  FIGS. 1-3 , and of the crawler control systems  152  of  FIG. 5 , the methods may be easily modified and applied to other embodiments. 
     Referring now to  FIG. 6 , a logic flow diagram illustrating a method of operating a production is shown. 
     In step  180 , the vehicle components  16 , such as an aircraft fuselage and other aircraft components and sub-assemblies, are supported in the production line  10  on the crawlers  20 . In step  182 , the first lift magnets  100  oppose the second lift magnets  102  to provide lift to the structural support  70 , thus lifting the aircraft components. 
     In step  184 , the onboard controllers  160  utilize the drive motors  156  to generate magnetic drive fields, which interact with the lift magnet fields generated by the first lift magnets  100  and cause the rolling tracks  44  to be translated in a predetermined direction. The movement of the rolling tracks  44  allows the crawlers  20  to move along the production line  10 . In step  186 , the onboard controllers  160  may adjust the drive magnetic fields experienced by the first lift magnets  100  to adjust the speed and the direction of travel of the crawlers  20 . 
     In step  188 , the stability magnets  122  generate magnetic stability fields. In step  190 , the superconducting devices  112  passively oppose any change in the magnetic stability fields to stabilize the rolling tracks  44  relative to the structural supports  70 . In response to the stability fields, current is generated within the superconducting devices  112 , which generates a resistance to change in the stability fields. This prevents lateral and vertical shifting of the rolling tracks  44  relative to the structural supports  70 . 
     In step  192 A, the speed sensors  170  generate speed signals indicative of rolling track speeds. In step  192 B, the onboard controllers  160  adjust the speed of the rolling tracks  44  by changing the magnitude of the drive magnetic fields. The onboard controllers  160  adjust the direction of travel of the rolling tracks  44  by changing the polarity of the drive magnetic fields in response to the speed signals. 
     In step  194 A, the position sensors  172  generate position or location signals indicative of the location of the crawlers  20 . In step  194 B, the onboard controllers  160  adjust the location of the crawlers  20  in response to the location signals. An onboard controller may adjust the speed or direction of travel of one or more of the rolling tracks of that crawler to alter the traveling direction. 
     In step  196 A, the temperature sensors  174  generate temperature signals indicative of the temperature of the superconducting devices  112 . In step  196 B, the onboard controllers  160  adjust the temperature of the cryostats  122  in response to the temperature signals using techniques known in the art. Steps  180 - 196 B may be continuously performed. 
     Referring now to  FIG. 7 , a logic flow diagram illustrating a method of manufacturing an aircraft is shown. 
     In step  200 , the vehicle components  16  are translated or conveyed along the production line  10  to the stations  18  using multiple production line cradle systems  14 . In step  200 A, the first lift magnets  100  oppose the second lift magnets  102  of each crawler  20  in the cradle systems  14  to provide lift to the structural supports  70 , thus lifting the aircraft components  16 . 
     In step  200 B, the onboard controllers  160  of the crawlers  20  utilize the drive motors  156  to generate magnetic drive fields, which interact with the lift magnet fields generated by the first lift magnets  100  and cause the rolling tracks  44  of the crawlers  20  to be translated in a predetermined direction. The movement of the rolling tracks  44  allows the cradle systems  14  to move to each station  18 . In step  200 C, the stability magnets  122  of the crawlers  20  generate magnetic stability fields. In step  200 D, the superconducting devices  112  passively oppose any change in the magnetic stability fields to stabilize the rolling tracks  44  relative to the structural supports  70 , as described above. 
     During step  200 , steps  162 A- 166 B may be performed to adjust speed, position, and direction of travel of the crawlers  20  or to adjust the temperature of any cooling device or superconducting device on the crawlers  20 . 
     In step  202 , one or more manufacturing tasks are performed at each station  18 . The manufacturing tasks may include the attaching of a component or sub-assembly to the fuselages, the adjusting, attaching, coupling, testing, and/or evaluating of components or systems, the painting or coating of the fuselages or any components or systems thereon, or any other manufacturing tasks known in the art. Steps  200 - 202  are continuously performed. 
     In step  204 , the remote controller  162  may generate a production line relocation signal or translocation signal for the translocating of the production line  10  to a different location. In step  206 , the onboard controllers  160  adjust the direction of travel of the crawlers  20  to move the production line  10  to a different location in response to the translocation signal. The onboard controllers  160  monitor the sensors  158  to confirm proper speed and direction of travel of the crawlers  20  during the translocation of the production line  10 . 
     The above-described steps in the methods of  FIGS. 6 and 7 , are meant to be an illustrative examples, the steps may be performed synchronously, continuously, or in a different order depending upon the application. 
     The disclosure provides a production line crawler and cradle system for the conveying of vehicle components along a production line. The crawler and cradle system allow for the translocating of a production line and for the easy accessing of vehicle components at various stations along the production line. The crawlers also allow for the interchanging thereof, which allows the realigning of station tasks. Certain crawlers may be setup and assigned to certain stations along a production line. Since the crawlers are mobile they may be arranged in different orders. Thus, the systems and methods disclosed provide production line mobility and flexibility. 
     While the systems and methods have been described in connection with one or more embodiments, it is to be understood that the specific mechanisms and techniques which have been described are merely illustrative of the principles disclosed, and numerous modifications may be made to the methods and apparatus described without departing from the spirit and scope of this disclosure as defined by the appended claims.