Abstract:
A method for manufacturing a mobile platform component that may involve attaching only a single rail to the mobile platform component, and positioning a carriage system having a main carriage and a secondary carriage on the rail. The main carriage may be positioned along a first axis of movement on the rail. The secondary carriage may be positioned along a second axis of movement perpendicular to the first axis of movement on the main carriage. The main carriage may be releasably secured to the secondary carriage, and the carriage system may be releasably secured to the mobile platform component.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 11/198,942 filed on Aug. 5, 2005. The disclosure of the foregoing related application is incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    The present disclosure relates to machines for drilling or performing other work operations on large work pieces configured as simple- or compound-contoured panels or the like, such as wing and fuselage sections for an aircraft. The disclosure relates more particularly to a flexible track machine and method for positioning a machining device such as a drill, marking device, or the like, relative to a work piece by traversing the machining device along a track mounted on and indexed to the work piece. 
       BACKGROUND 
       [0003]    The problem of accurately drilling holes in large work pieces such as aircraft wing and fuselage panels and other types of structures has been an ongoing challenge in the aircraft industry as well as other industries. A particular challenge is being able to drill holes in a wide range of work piece configurations. Large fixed-mounted machines such as five-axis drilling machines can be used for some types of work pieces, but these machines are quite expensive to procure and operate. In contrast, a relatively low-cost solution to the above-noted problem that has been developed by the assignee of the present application is to mount an automated drill or other machining device on a tract that is mounted to the work piece. The drill or machining device is supported on a carriage that travels along the track, which is formed by a pair of parallel rails mounted on the work piece. For examples of such devices, see U.S. Pat. No. 4,850,763, assigned to the assignee of the present application, and incorporated herein by reference, and U.S. Pat. No. 3,575,364, and U.S. Pat. No. 6,843,328 B2 also incorporated by reference herein. 
         [0004]    With many prior devices, such devices were applied to work pieces that did not have compound-contoured surfaces. As used herein, the term “compound-contoured” (also known as “doubly curved”) is used to denote a surface having curvature in more than one direction. On such a compound-contoured surface, it is possible in general to lay a pair of straight, flexible rails such that the rails conform to the surface contour and are the same distance apart at all points along the rails. Thus, the surface of a sphere is an example of a compound-contoured surface, because the rails can be laid in circumferential, axial, or helical directions and the spacing between them can be constant. 
         [0005]    With other previously developed devices, a pair of flexible rails is mounted in the circumferential direction around a circular cylindrical work piece. It will be appreciated that the rails were made flexible so that they can conform to a variety of surfaces, but even such flexible rails cannot be positioned exactly the same distance apart at all points along the rails when they are mounted on a compound-contoured surface. Furthermore, the rails mounted along two different paths on a compound-contoured surface will twist differently from one another because of the different directions of the surface normal along the two paths. This can make it difficult to traverse a carriage along the rails and maintain acceptable accuracy of carriage positioning. 
         [0006]    With some previously developed devices, a pair of spaced rails is mounted on a compound-contoured surface such that the rails are the same distance apart at all points along the rails. A Y-axis motor and an X-axis motor are supported on a carriage unit that is free to move along the rails. Additionally, the rails are mounted to the surface via vacuum cups. One drawback with such systems is that the rails and the carriage system may not provide enough stability during drilling in order to drill precise holes in a work piece. Moreover, the cost of fabricating drill plates is very costly for this type of two-rail drilling system because a drill plate is made for one specific area of the work piece. Additionally, each drill plate must be made to match the mode line contour of the work piece and establish an exact hole location. Therefore, it is desirable to have a rail system with fewer parts so that an operator can even more easily set up the drilling rail system for use. Additionally, a drilling rail system is needed which provides even better adhesion over seams and holes located on the surface of the work piece, to enable even more accurate and precise holes to be formed in the work piece. 
       SUMMARY 
       [0007]    In one aspect the present disclosure involves a method for manufacturing a mobile platform component. The method may involve attaching only a single rail to the mobile platform component, and positioning a carriage system having a main carriage and a secondary carriage on the rail. The main carriage may be positioned along a first axis of movement on the rail. The secondary carriage may be positioned along a second axis of movement perpendicular to the first axis of movement on the main carriage. The main carriage may be releasably secured to the secondary carriage, and the carriage system may be releasably secured to the mobile platform component. 
         [0008]    In another aspect the present disclosure may involve a method for manufacturing a mobile platform component, where the method may involve attaching only a single rail to the mobile platform component, and positioning a carriage system having a main carriage and a secondary carriage on the rail. The main carriage may be positioned along a first axis of movement on the rail. The secondary carriage may be positioned on the main carriage and along a second axis of movement perpendicular to the first axis of movement. The secondary carriage may be clamped to the main carriage in one of a fully clamped condition relative to a workpiece, a partially clamped condition relative to the workpiece, and an unclamped condition relative to the workpiece. A coupling device may be used to anchor the secondary carriage to the mobile platform component. 
         [0009]    In still another aspect the present disclosure involves a method for manufacturing a mobile platform component. The method may involve using an elongated flexible rail including a plurality of attachment devices adapted to releasably attach the rail to a work piece, with the rail including a longitudinal axis and a transverse axis. A main carriage may be operatively coupled to the rail so that the main carriage is longitudinally moveable. A secondary carriage may be operatively coupled to the main carriage so that the secondary carriage is transversely moveable and adapted to receive a machining device. A fastening device may be used to couple the main carriage and the secondary carriage, wherein the fastening device is adapted to clamp the secondary carriage on to the main carriage, and wherein the main carriage and the secondary carriage are braced against one another to prevent the secondary carriage from moving. A coupling device may be associated with the secondary carriage and operative to releasably affix the secondary carriage to the surface of the work piece by vacuum. A controller may be used in communication with the coupling device to control the coupling device so that the coupling device is used to place the secondary carriage and the main carriage in any one of a fully clamped state relative to the work piece, a fully unclamped state relative to the work piece, and a partially clamped state relative to the work piece. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0011]      FIG. 1  is a perspective view of a vacuum mounted drilling apparatus in accordance with a preferred embodiment of the present disclosure; 
           [0012]      FIG. 2  is a perspective view of the vacuum mounted drilling apparatus of  FIG. 1 ; 
           [0013]      FIG. 3  is a cross-sectional view of a carriage system in accordance with a preferred embodiment of the present disclosure; 
           [0014]      FIG. 4  is a cross-sectional view similar to  FIG. 3 , wherein a Y-axis carriage is clamped to an X-axis carriage; 
           [0015]      FIG. 5  is an exploded view of a fastening device coupling the carriage system to a machining device; 
           [0016]      FIG. 6  is a side view of a mono-ball mounting apparatus in accordance with a preferred embodiment of the present disclosure; 
           [0017]      FIG. 7  is a bottom view of the mono-ball mounting apparatus; 
           [0018]      FIG. 8  is a side diagrammatic view of the machining device in an extended position; 
           [0019]      FIG. 9  is a side elevational view of the machining device, without the mono-ball mounting apparatus, in an extended position and constructed in accordance with the teachings of the present embodiment of the present disclosure; 
           [0020]      FIG. 10  is a front perspective view of the machining device, without the mono-ball mounting apparatus, in  FIG. 9 ; and, 
           [0021]      FIG. 11  is a cross-sectional view taken along line  3 - 3  of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    The following description of the various embodiments is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the specific embodiments set forth herein. 
         [0023]    With reference to  FIGS. 1-2 , a vacuum mounted drilling system, apparatus or machine  10  in accordance with an embodiment of the disclosure is shown. Machine  10  comprises a rail  12  to which a plurality of attachment devices  14 , preferably fixed in the form of vacuum cup assemblies, are releasably affixed at spaced intervals along the length of rail  12 . Additionally, rail  12  preferably includes a ratio of two vacuum cups for every vacuum generator to improve adhesion over seams and holes on a surface  16  of a work piece  18 . Rail  12  preferably has a width substantially greater than its thickness. This makes the rail  12  substantially stiffer in bending about an axis that extends in the thickness direction than the rail  12  is about an axis that extends in the width direction. 
         [0024]    The width of rail  12  extends substantially parallel to surface  16  of work piece  18  when vacuum cup assemblies  14  are attached to surface  16 . Because rail  12  is able to easily bend about the widthwise directions and to twist about its longitudinal axes, rail  12  flexes and twists as needed to substantially follow surface  16  of work piece  18 . In other words, rail  12  is configured to a topography or geometry of surface  16  of work piece  18  in a spaced relationship. Vacuum cup assemblies  14  maintain rail  12  at a substantially constant distance from surface  16  of work piece  18 . In this manner, the major surfaces of rail  12  are substantially parallel to surface  16  of work piece  18  at any point along rail  12 . 
         [0025]    Mounted on rail  12  is a carriage system  19 . Carriage system  19  includes a main or X-axis carriage  20  and a secondary or Y-axis carriage  24 . X-axis carriage  20  slides along rail  12  by virtue of rollers  22  that are mounted on X-axis carriage  20  and that engage rail  12 . X-axis carriage  20  comprises a plate-shaped member. Rollers  22  are mounted along each of the opposite side edges of X-axis carriage  20 . Vacuum mounted drilling machine  10  enables X-axis carriage  20  to traverse rail  12  along the X-axis (i.e., the X-axis or longitudinal axis is parallel to the length direction of rail  12 ) even though rail  12  may be bending and twisting. In effect, rail  12  conforms to the contour of work piece surface  16  and thus remains approximately parallel to surface  16  at any point along the path defined by rail  12 . 
         [0026]    Rail  12  is received between opposing rollers  22 . Rail  12  preferably has V-shaped edges engaged by rollers  22 , and rollers  22  are V-grooved rollers  22  that receive the V-shaped edges of rail  12 . Rollers  22  thus prevent relative movement between rollers  22  and rail  12  in the direction along the rotational axes of rollers  22 , which are substantially normal to work piece surface  16 . Additionally, an X-axis handle  23  is coupled to X-axis carriage  20  in order to aid an operator to position X-axis carriage  20  to a desired location along the X-axis. 
         [0027]    Y-axis carriage  24  is slidably mounted atop X-axis carriage  20 , so that Y-axis carriage  24  can slide back and forth along a Y-axis or transverse axis direction perpendicular to the X-axis direction, wherein the Y-axis is parallel to the width direction of rail  12 . More particularly, a fastening device  26  couples X-axis carriage  20  to Y-axis carriage  24 . Additionally, fastening device  26  is adapted to clamp Y-axis carriage  24  downward to X-axis carriage  20 . This causes X-axis carriage  20  and Y-axis carriage  24  to brace against one another to prevent Y-axis carriage  24  from moving along the Y-axis. Fastening device  26  comprises a pair of double acting cylinders  26  seated adjacent to an elongated U-shaped channel  28  formed in Y-axis carriage  24 . Each double acting cylinder  26  may be any conventional double acting cylinder, such as a 11/2″ Bore Air Cylinder, Model No. 172-DXDEH, manufactured by the Bimba Manufacturing Company of Monee, Ill. 
         [0028]    As shown in  FIGS. 3 and 4 , each double acting cylinder  26  includes an air-driven piston (not shown), having a first side and a second side. A first piston rod  30 , coupled to the air-driven piston, extends from a front portion  32  of each double acting cylinder  26 . First piston rod  30  of each double acting cylinder  26  is extended through U-shaped channel  28  and coupled to X-axis carriage  20 . Furthermore, first piston rod  30  is coupled to X-axis carriage  20  via a threaded portion (not shown) at a forward end  34  of first piston rod  30  which is extended through and screwed into a threaded nut  36  and into a threaded hole  35  in X-axis carriage  20 , as shown in  FIGS. 3 and 4 . 
         [0029]    With further reference to  FIG. 2 , Y-axis carriage  24  includes a first side  58  and a second side  60 . A Y-axis handle  62  is coupled atop Y-axis carriage  24  and located on first side  58 . Y-axis handle  62  is operative to slide Y-axis carriage  24  between first piston rod  30  of each double acting cylinder  26 . Furthermore, located beneath first side  58  of Y-axis carriage  24 , a coupling device  64  is affixed to Y-axis carriage  24 . Coupling device  64  is adaptive to substantially affix Y-axis carriage  24  to work piece  18  by vacuum. In other words, coupling device  64  is operative to anchor carriage system  19  to work piece  18  and prevent carriage system  19  from moving along the X-axis. Additionally, coupling device  64  is preferably in the form of a vacuum cup assembly. Coupled to vacuum cup assembly  64  is a vacuum generator (not shown) to activate vacuum cup assembly  64 . 
         [0030]    Mounted onto X-axis carriage  20  and coupled to double acting cylinders  26  is a controller (not shown). Additionally, a first fluid supply line  40  is coupled to a T-fitting  41 , such as an air fitting ( FIG. 2 ). In general, first fluid supply line  40  supplies fluid, such as compressed air, to T-fitting  41  via an air supply (not shown). A second fluid supply line  48  is coupled to the input of the controller and a first outlet  41   a  of T-fitting  41 . The controller includes an input (not shown), while also including a first-air output (not shown), a second-air output (not shown), a third-air output (not shown), and a fourth-air output (not shown). Inside the controller, the input of the controller is coupled to a first valve (not shown) and a second valve (not shown). The first valve and the second valve may include any two suitable four-way pneumatic air valves, such as two four-way pneumatic valves Part No. D20-DM-AM-A manufactured by Dynamco, Inc. of Commerce, Ga. The first valve includes a first valve input, the first-air output, and the second-air output. Additionally, the second valve includes a second valve input, the third-air output, and the fourth-air output. 
         [0031]    Additionally, the controller includes two operator-initiated controls (not shown), a first-actuating control and a second-actuating control. The first-actuating control and the second-actuating control may include any suitable manually operated 4-way valve such as a valve Part No. D20DMAMA manufactured by Dynamco, Inc. The first-actuating control is coupled to the first valve. The first-actuating control is operative to channel fluid from the first-air output to the second-air output and vice versa. The second-actuating control is coupled to the second valve. The second-actuating control is operative to channel fluid away from the third-air output to the fourth-air output and vice versa. 
         [0032]    A first-air-output line (not shown) is coupled to the first-air output and vacuum cup assembly  64 . The first-air-outlet line provides fluid to the vacuum cup assembly. A second-air-output line (not shown) is coupled to the second-air output of the controller and front portion  32  of each double acting cylinder  26 . The second-air-outlet line provides fluid to the first side of the air-driven piston through front portion  32  of each double acting cylinder  26 . A third-air-output line (not shown) is coupled to the third-air output of the controller and the rear portion of each double acting cylinder  26 . Additionally, the third-air-output line provides fluid to the second side of the air-driven piston through the rear portion of each double acting cylinder  26 . A fourth-air-output line (not shown) is coupled to the fourth-air output of the controller and the vacuum generator of vacuum cup assembly  64 . The fourth-air-output line provides fluid to the vacuum generator. 
         [0033]    Referring to  FIG. 2 , air fitting  41  is constantly powered or pressurized by the air coming from the air supply via first fluid supply line  40 . Therefore, second fluid supply line  48  provides a constant source of pressurized air or power to the controller. Additionally, the controller allows the constant pressure of air provided through second fluid supply line  48  to travel through the controller and out the second-air output to the rear portion of each double acting cylinder  26 . Due to the air being constantly supplied to each double acting cylinder  26 , the air-driven piston is placed in an extended or forward position. 
         [0034]    Mounted to second side  60  of the Y-axis carriage  24  is a power tool assembly or machining device  70  adapted to manipulate surface  16  of work piece  18 . As shown in  FIG. 5 , machining device  70  may be temporarily coupled to second side  60  of Y-axis carriage  24  via an attachment fixture  84 , such as a tooling knob. As shown in FIGS.  5  and  8 - 11  of the drawings, machining device  70  is illustrated to include an attachment member  71 , a drilling plate  72 , a mounting unit  74 , and a power feed attachment  86 , which is constructed in accordance with the teachings of the present disclosure and that of U.S. Pat. No. 6,776,562, and herein incorporated by reference, and a power tool  88 , which, in the example provided is a drill  88 . 
         [0035]    More specifically, as shown in  FIGS. 2 ,  5  and  6 , mounted to second side  60  of Y-axis carriage  24  is attachment member  71 , having a top side  71   a  and a bottom side  71   b . Referring to  FIGS. 6 and 8 , attachment member  71  includes a first guiding pin  73   a  and a second guiding pin  73   b  coupled to top side  71   a . First guiding pin  73   a  and second guiding pin  73   b  align attachment member  71  with Y-axis carriage  24 . Bottom side  71   b  of attachment member  71  is affixed to drill plate  72 . Drill plate  72  is coupled to mounting unit  74  having a mono-ball device  76 , wherein mono-ball device  76  allows mounting unit  74  to follow the contour of surface  16  of work piece  18 . Mounting unit  74  may pivot between a plurality of position, such as a first position and a second position, as shown in  FIG. 6 . 
         [0036]    Referring to  FIGS. 6 ,  7  and  8 , mounting unit  74  includes a plurality of gripping mechanisms or contact feet  78 . Contact feet  78  are mounted along each of the opposite edges of mounting unit  74 . Contact feet  78  may be made of a polymeric material, such as Delrin.RTM. Additionally, contact feet  78  substantially prevent mounting unit  74  from moving once placed in contact with surface  16  of work piece  18  during a drilling process. Furthermore, drill plate  72 , mounting unit  74 , and mono-ball device  76  include bores  80   a ,  80   b  and  80   c , respectively, that are concentrically aligned to form an elongated bore  80  ( FIGS. 6 and 8 ). 
         [0037]    As shown in FIGS.  2  and  8 - 10 , drill  88  generally includes a pistol grip  90  affixed to a motor casing  92 . Motor casing  92  encloses a motor (not shown), which is activated by pressing a trigger  94 . Activation of the motor conventionally rotates a spindle  96  and a chuck  98 . Chuck  98  holds a tool bit  82 . Tool bit  82  may be any appropriate tool bit including a drill bit or a countersink bit. Tool bit  82  is capable of passing through each elongated bore  80  to engage surface  16  of work piece  18 . Referring to  FIGS. 9 ,  10 , and  11 , affixed to pistol grip  90  and extending from an end opposite motor casing  92  is a male coupling  100  that connects to a female coupling  102  of a fluid supply hose  103  extending from a power source  93 . In particular, the fluid supplied to drill  88  is compressed air. However, drill  88  could alternatively be electrically powered. 
         [0038]    Referring to  FIG. 10 , power feed attachment  86  may be affixed to drill  88  through any suitable means. As an example, yoke or clamp portion  180  extends from housing  140 , wraps around motor casing  92 , and is held in place by a screw  184 . 
         [0039]    In  FIGS. 9 ,  10 , and  11 , power feed attachment  86  is shown to generally include a third-double-acting-air cylinder  104 . Third double acting air cylinder  104  is shown in detail in  FIG. 11  and may be any conventional double acting air cylinder, such as a 01 Series Micro-Air Cylinder, Part No. 0118-5029-010, manufactured by the ARO Corporation of Bryan, Ohio. Third double acting air cylinder  104  includes an air-driven piston  106  having a first side  106   a  and a second side  106   b . A first piston rod  108  is coupled to air-driven piston  106  and extends from a front portion  104   a  of double acting air cylinder  104 . First piston rod  108  engages an intermediate or connection member  110  through a threaded portion  112  at a forward end  108   a  of first piston rod  108  and a rearward end  110   a  of connection member  110 . Furthermore, a forward end  110   b  of connection member  110  includes threads  110   c  that engage a forward or guide arm  114  of power feed attachment  86 . Affixed to guide arm  114  is a bushing  116 . Guide arm  114  and bushing  116  guide tool bit  82  during the actuation of drill  88 . Bushing  116  may be affixed to guide arm  114  through any suitable means and is shown to be clamped between two portions of guide arm  114  and affixed in place with a screw  118 . 
         [0040]    Bushing  116  may be any conventional bushing that may be affixed to drill plate  72 . Many bushings are available to interact with different drill plates and a proper bushing may be chosen depending upon the application. Referring to  FIG. 10 , a resilient member  120 , which may be formed of any suitable material, may be affixed around bushing  116 , and extend in front of bushing  116 , to allow a press fit onto work piece  18 . According to the present embodiment, resilient member  120  is formed of a polymeric material to reduce movement of power feed attachment  86  during use. 
         [0041]    With further reference to  FIGS. 9 and 10 , power feed attachment  86  also includes a control system  122  including a hydraulic cylinder  124  having a front end  124   a  with a front portion  126  of a second piston rod  128  extending therefrom. Control system  122  also includes a variable connection or attachment member  130  that couples second piston rod  128  to guide arm  114 . Hydraulic cylinder  124  may be any suitable hydraulic cylinder such as a Slimline Kineschek Feed Control Part No. 1002-31-1 manufactured by Deschner Corporation of Santa Ana, Calif. Front portion  126  of second piston rod  128  engages guide arm  114  through variable attachment member  130 . Variable attachment member  130  includes a threaded bore  132  that receives front portion  126  of second piston rod  128 . Front portion  126  of second piston rod  128  engages a set screw  133 . Set screw  133  is received in threaded bore  132  ( FIG. 10 ) and may be adjusted in and out of threaded bore  132  to adjust the effective length of second piston rod  128 . A nut  134  ( FIG. 9 ) engages set screw  133  and acts as a jamb nut against variable attachment member  130  to hold set screw  133  at the desired position. A rear side  136  of variable attachment member  130  engages nut  134  forming a datum surface. 
         [0042]    As described herein, when power feed attachment  86  is activated, guide arm  114  is forced away from chuck  98  in the opposite direction of Arrow A to an extended position. Once trigger  94  of drill  88  is pressed, power feed attachment  86  is mobilized and guide arm  114  is drawn towards chuck  98  in the direction of Arrow A to a retracted position. As also described herein, control system  122  controls the rate of movement of guide arm  114  by engaging variable attachment member  130  with set screw  133 . Set screw  133  may be adjusted rearwardly or forwardly in threaded bore  132  to adjust the distance of retraction depending upon the application in which machining device  70  will be used. Referring to  FIG. 9 , an adjustment screw  138  allows a varying resistance to be produced by hydraulic cylinder  124 . Adjustment screw  138  allows resistance produced by hydraulic cylinder  124  to be adjusted so that rate of the retraction of power feed attachment  86  may be precisely controlled. 
         [0043]    Referring further to  FIGS. 2 ,  9  and  11 , affixed adjacent to a housing  140  of power feed attachment  86  is a module  150 . Module  150  includes a valve (not shown). The valve may be any suitable 2-position valve with a spring return such as an Eagle 4-way Valve Part No. E4-1 PS00-000 manufactured by the Clippard Instrument Laboratory, Inc. of Cincinnati, Ohio. The valve includes at least a first inlet  152 , a second inlet  154 , a first outlet  162 , and a second outlet  160  ( FIGS. 9 and 11 ). A third-fluid-supply line  164  ( FIGS. 9 and 11 ) connects a second outlet  41   b  of air fitting  41  to first inlet  152 . Alternatively, third-fluid-supply line  164  may be coupled to male coupling  100  to transport fluid or compressed air from power supply  93  to first inlet  152  of module  150 . A second inlet line  168  connects a second bore  170  ( FIG. 9 ) formed in motor casing  92  to second inlet  154 . Second bore  170  in motor casing  92  is drilled through the outside cast wall of motor casing  92 . Second bore  170  reaches an internal cavity (not shown) that becomes pressurized when trigger  94  is pressed. 
         [0044]    A first-outlet-drive line  172  ( FIG. 9 ) connects first outlet  162  and a rear portion  104   b  of third-double-acting-air cylinder  104 . A second-outlet-drive line  176  connects front portion  104   a  of third-double-acting-air cylinder  104  to second outlet  160 . Referring briefly to  FIGS. 9 and 11 , first-outlet-drive line  172  provides fluid to first side  106   a  of air-driven piston  106  while second-outlet-drive line  176  provides fluid to second side  106   b  of air-driven piston  106 . 
         [0045]    Additionally, module  150  includes a third-actuating control  186  and a fourth-actuating control  188 . Third-actuating control  186  includes a spring return valve, such as a spring return valve Part No. D20-SM-K0-A manufactured by Dynamco, Inc. Third-actuating control  186  is coupled to the valve and fourth-actuating control  188 . Third-actuating control  186  includes a first position and a second position. Third-actuating control  186  is operative to channel fluid from first outlet  162  to an input of fourth-actuating control  188  and vice versa. Third-actuating control  186  is adaptive to allow spindle  96  to be advanced toward surface  16  of work piece  18  without using trigger  94  or without spindle  96  rotating. When activated, fourth-actuating control  188  is operative to channel fluid from an output of the fourth-actuating control  188  to second outlet  160 , thereby providing fluid to second side  106   b  of air-driven piston  106  and causing advancement of spindle  96  toward surface  16  of work piece  18 . 
         [0046]    Referring to  FIGS. 2 ,  9  and  11 , air fitting  41  is constantly powered or pressurized by the air coming from the air supply, as previously mentioned. Therefore, third-fluid-supply line  164  provides a constant source of pressurized air or power to module  150  of power feed attachment  86 . Additionally, module  150  allows the constant pressure of air provided through third-fluid-supply line  164  to travel through module  150  and out first-outlet-drive line  172  to rear portion  104   b  of third-double-acting-air cylinder  104 . Due to the air being constantly supplied to third-double-acting-air cylinder  104 , air-driven piston  106  is placed in the extended position, as shown in  FIGS. 9 ,  10 , and  11 . In turn, this maintains guide arm  114  in the extended position, which is distal from chuck  98 , and bushing  116  at a maximum allowable distance from chuck  98 . 
         [0047]    Drill  88  in this example is a pneumatic powered drill. Pressurized air is received through male coupling  100  and then travels through drill  88  to power the motor to rotate chuck  98 . When an operator of drill  88  presses trigger  94 , pressurized air travels to motor casing  92  and powers the motor. When air enters motor casing  92 , air also pressurizes second inlet line  168  through second bore  170 . Second bore  170  in motor casing  92  allows air to travel out of motor casing and into the valve of module  150 . Thereafter, the valve of module  150  transfers the pressurized air from first-outlet-drive line  172  to second-outlet-drive line  176 . When this occurs, front portion  104   a  of third-double-acting-air cylinder  104 , and second side  106   b  of air-driven piston  106 , become pressurized. This drives air-driven piston  106  in a rearward position towards rear portion  104   b  of third-double-acting-air cylinder  104 , as shown in  FIG. 11 . Therefore, the mobilized position of machining device  70  is the retracted position. 
         [0048]    In particular, the retracted position moves bushing  116  in the direction of Arrow A to dispose bushing  116  nearer chuck  98 . Thus, retraction of first piston rod  108  into cylinder portions of double acting air cylinder  104  cause drill spindle  96  to be advanced toward work piece  18 , and extension of first piston rod  108  causes drill spindle  96  to be retracted away from work piece  18 . If power feed attachment  86  includes no controlling mechanisms, the movement from the extended to the retracted position would be almost instantaneous. This is because the air pressure is simply diverted from first side  106   a  to second side  106   b  of air-driven piston  106  allowing guide arm  114  to retract toward chuck  98  as rapidly as the pressure of the air allows. 
         [0049]    When an operator initiates third-actuating control  186  to deactivate spindle  96 , module  150  prevents spindle  96  from rotating. Using fourth-actuating control  188 , spindle  96  may be advanced without rotation toward surface  16  of work piece  18 . Additionally, fourth-actuating control  188  allows spindle  96  to be incrementally advanced by selectively engaging and disengaging fourth-actuating control  188 . When this occurs, module  150  pressurizes front portion  104   a  of third-double-acting-air cylinder  104  and second side  106   b  of air-driven piston  106 . This drives air-driven piston  106  in the retracted position towards rear portion  104   b  of third-double-acting-air cylinder  104 . 
         [0050]    Control system  122  controls the rate of retraction of guide arm  114 . In particular, hydraulic cylinder  124  of control system  122  provides hydraulic resistance through second piston rod  128  and variable attachment member  130 . As guide arm  114  is drawn towards chuck  98 , guide arm  114  interacts with hydraulic cylinder  124 . The resistance in hydraulic cylinder  124  controls the retraction of guide arm  114  towards chuck  98 . Set screw  133  may also be adjusted to set the maximum distance of retraction of guide arm  114  towards chuck  98 . Moving set screw  133  in threaded bore  132 , changes the effective length of second piston rod  128 . If set screw  133  is made to decrease the effective length of second piston rod  128 , then there is less distance for second piston rod  128  to travel in hydraulic cylinder  124  thereby decreasing the distance that guide arm  114  may travel. 
         [0051]    Adjustment screw  138  allows the resistance produced by hydraulic cylinder  124  of control system  122  to be adjusted. Increasing the resistance created by hydraulic cylinder  124  decreases the rate of the retraction of guide arm  114  towards chuck  98 . Whereas, reducing the resistance of hydraulic cylinder  124  increases the retraction rate of guide arm  114  towards chuck  98 . Various applications require differing rates of feed of tool bit  82  through work piece  18 . Adjustment of set screw  133  also allows for a precise depth of tool bit  82  into work piece  18 . Therefore, a continuous and easily repeated rate and depth of tool bit  82  into work piece  18  is reproduced by simply adjusting set screw  133  and adjustment screw  138  of power feed attachment  86 . 
         [0052]    Additionally, module  150  includes a laser-actuating control  190  and an incandescent light actuating control  192 . Laser-actuating control  190  is coupled to a laser source  194 , such as a laser diode, to guide or aid an operator to properly align machining device  70  with a desired location to drill a hole. As shown in  FIG. 7 , laser source  194  emits a laser light in a direction of surface  16  of work piece  18 . Incandescent light actuating control  192  is coupled to an incandescent or non-coherent light source  196  that guides and assists the operator in drilling a hole on surface  16  of work piece  18 . 
         [0053]    Referring to  FIG. 2 , machining device  70  includes a vacuum collection hose  198 . Vacuum collection hose  198  is coupled to mounting unit  74 . Vacuum collection hose  198 , in turn, is coupled to a vacuum generator (not shown). Vacuum collection hose  198  suctions loose debris and shavings around a desired location selection for drilling. 
         [0054]    During the operation of positioning machining device  70 , an operator places rail  12  adjacent to a fabricated hole pattern located on surface  16  of work piece  18  to be drilled. The hole pattern may have been previously determined by, for example, a laser projection or spray dot templates. The operator activates the air powered vacuum generators to securely pull rail  12  down to surface  16  of work piece  18 . 
         [0055]    Carriage system  19  is then slid along the X-axis and the Y-axis to position and align machining device  70  over the marked locations. After sliding carriage system  19  onto rail  12 , machining device  70  is coupled to carriage system  19  via tooling knob  84 . Using the controller, the operator may select and activate a full clamp feature or function, a partial clamp feature or function, or a full unclamp feature or function. Toggling the first-actuating control of the controller activates the partial clamp function to bias the first valve into a first position. The partial clamp function channels fluid away from the second-air output to the first-air output of the controller to vacuum cup assembly  64  such that neither the first side nor the second side of the air-driven piston within double acting cylinders  26  receives fluid from the controller. This allows Y-axis carriage  24  to move slightly along the Y-axis. Additionally, during activation of the partial clamp function, fluid is also supplied to vacuum cup assembly  64 . This causes vacuum cup assembly  64  to act as an air float device that allows carriage system  19  to move along the X-axis. 
         [0056]    Switching the first-actuating control of the controller to a second position initiates the full clamp function to bias the first valve from the first position into a second position. The full clamp function occurs when fluid is channeled away from first-air output to the second output of the controller and is applied to the second side of the air-driven piston causing first piston rod  30  to retract into double acting cylinders  26 . Retracting the first piston rod  30  of each double acting cylinder  26  causes Y-axis carriage  24  to brace against X-axis carriage  20  substantially preventing movement in the Y-axis. 
         [0057]    On the other hand, toggling the second-actuating control of the controller to a first position activates the full unclamp function to bias the second valve into a first position. The full unclamp function is indicative of fluid being supplied from the third-air output to the first side of the air-driven piston. This causes a previously supplied force applied to Y-axis carriage  24  to be released which allows full movement of carriage system  19  along the X-axis and the Y-axis. Additionally, switching the second-actuating control of the controller to a second position initiates the full clamp function to bias the second valve into a second position. This causes fluid to be channeled away from the third-air output to the fourth air output and to the vacuum generator of vacuum cup assembly  64  causing the vacuum cup assembly  64  to adhere to surface  16 . 
         [0058]    Once machining device  70  is properly positioned, the operator toggles the first-actuating control to the second position for the full clamp function to cause double acting cylinders  26  to clamp Y-axis carriage  24  to X-axis carriage  20 . Clamping Y-axis carriage  24  to X-axis carriage  20  also forces all four contact feet  78  of mounting unit  74  against surface  16  to cause friction between contact feet  78  and the surface  16  to prevent movement of carriage system  19  in the X-axis and the Y-axis. In order to remain normal to the contour of surface  16  of work piece  18 , mounting unit  74  pivots in any direction necessary. Additionally, the operator toggles the second-actuating control to the second position for the full clamp function to supply fluid to the vacuum generator for the vacuum cup assembly  64 . The vacuum generator reduces the pressure of a gas in vacuum cup assembly  64  thereby causing an increase in vacuum within vacuum cup assembly  64  to further prevent movement along the X-axis. With dual acting cylinders  26  and vacuum cup assembly  64  activated, carriage system  19  is sufficiently secure to prevent movement along the X-axis and the Y-axis while machining device  70  manipulates surface  16  of work piece  18 . 
         [0059]    To help locate a previously marked hole of the hole pattern, laser source  194  is provided to further position tool bit  82  to the exact location of the desired marked hole of work piece  18 . Laser source  194  also facilitates precise positioning of machining device  70  relative to a location where a machining operation is to be performed. Additionally, incandescent light source  196  is further used to aid the operator to align machining device  70  with the hole pattern. 
         [0060]    The operator may also toggle third-actuating control  186  of module  150  to a second position to advance spindle  96  without using trigger  94  or causing spindle  96  to rotate. Once third-actuating control  186  is switched to the second position, fluid is channeled from first outlet  162  to the input of fourth actuating control  188 . As the fourth-actuating control  188  is activated, spindle  96 , without rotating, is advanced toward surface  16 . The operator may advance spindle  96  toward surface  16  of work piece  18  using fourth-actuating control  188 . As long as the operator activates fourth-actuating control  188 , spindle  96  will continue to advance toward surface  16  of work piece  18  until second piston rod  128  has reached a maximum retraction travel distance and guide arm  114  stops the travel towards the retracted position. When the operator deactivates fourth-actuating control  188 , spindle  96  will remain in its current position until the operator toggles third-actuating control  186  into the first position or presses trigger  94 . If the operator presses trigger  94  while third actuating control  186  is placed in the second position, spindle  96  will begin to rotate and advance toward surface  16  of work piece  18  to manipulate surface  16 . On the other hand, if the operator sets third-actuating control  186  in the first position, third-actuating control  186  channels fluid from the input of fourth-actuating control  188  to first outlet  162 , thereby causing fluid to return to the first side  106   a  of air-driven piston  106  and drives guide arm  114  toward the extended position. 
         [0061]    Additionally, during the drilling operation the operator of machining device  70  moves machining device  70  through a feed cycle. The feed cycle includes an extended position to retracted position to extended position action. Power feed attachment  86  performs the entire cycle while the operator has to hold drill  88  and operate trigger  94 . Once guide arm  114  has retracted enough towards chuck  98 , second piston rod  128  has reached a maximum retraction travel distance, bushing  116  and guide arm  114  stop the travel towards the retracted position. When the retracted motion has stopped, the operator of machining device  70  may release trigger  94  to stop the drilling process. Additionally, when trigger  94  has been released motor casing  92  is no longer pressurized with air from power source  93 . Therefore, second bore  170  is also not pressurized, thus removing pressure from second inlet line  168  of module  150 . 
         [0062]    Upon detection of the removal of pressure from second inlet line  168 , module  150  transfers air from third-fluid-supply line  164  and out first-outlet-drive line  172  to pressurize first side  106   a  of air-driven piston  106 . This drives air-driven piston  106  towards front portion  104   a  of third-double-acting-air cylinder  104  and drives guide arm  114  towards the extended position. In this way, third-double-acting-air cylinder  104  provides pneumatic power to move power feed attachment  86  between the retracted and extended positions. The pneumatic power provided by third-double-acting-air cylinder  104  helps ensure that enough power is provided for extended usage and reduced maintenance or cleanings of the present disclosure. In particular, the pneumatic power provided to third-double-acting-air cylinder  104  provides enough power or force to overcome most general resistances which may form in third-double-acting-air cylinder  104  due to foreign materials entering the cylinder or foreign materials entering housing  140 . 
         [0063]    Control system  122  also allows for an easily repeatable rate of retraction. Once the retraction rate has been set, using hydraulic cylinder  124  and adjusting the resistance with adjustment screw  138 , machining device  70  will always advance with the rate that has been chosen. Therefore, power feed attachment  86  may be adjusted to provide a repeatable, predetermined rate of retraction allowing that rate to be applied to guide arm  114  to move machining device  70 . Additionally, the use of variable attachment member  130  and second piston rod  128  allows for an easily repeatable depth of tool bit  82  into work piece  18 . Therefore, the operation of machining device  70  is easily repeatable with minimal control being necessary from an operator. For exemplary purposes only, a repeatable countersink variance of about 0.0015 inches (0.0381 mm) in hole diameter and 0.007 inches (0.178 mm) in countersink diameter was achieved when a counter sink tool bit was used. Also as an example, if a drill bit is chosen as tool bit  82 , a diameter of about 1.61 mm (0.063 inches) may be used with this embodiment. 
         [0064]    Many modifications and other embodiments will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing description and the associated drawings. For example, while rail  12  in the illustrated embodiment achieves relative flexibility about one axis and relative stiffness about a perpendicular axis by virtue of its width being much greater than its thickness, it will be recognized that there are other ways of achieving this characteristic. As an example, while rollers  22  are shown for engaging rail  12 , other types of members could be used instead of rollers  22  for engaging the rail. Moreover, more than one rail may be used, although not all of the benefits of the one rail system may be achieved with multiple rails. Additionally, attachment member  71  may be eliminated and drill plate  72  may be directly attached to Y-axis carriage  24 . Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 
         [0065]    While various preferred embodiments have been described, those skilled in the art will recognize modifications or variations that might be made without departing from the inventive concept. The examples illustrate the disclosure and are not intended to limit it. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.