Abstract:
A tool for in-situ airfoil contouring is provided. The tool has a pathway for an airfoil edge wherein the edge movement is limited and further wherein the edge is exposed to a grinding structure having a preselected profile shape therein. The tool makes this contouring process available for airfoils without the necessity of removing the airfoils from, for example, an aircraft engine.

Description:
BACKGROUND 
       [0001]    The disclosed embodiments generally pertain to a contouring tool. More specifically disclosed embodiments pertain to a contouring tool for a leading or trailing edge of an airfoil. 
       SUMMARY 
       [0002]    According to at least one embodiment, an in-situ airfoil contouring tool is provided. The tool provides a contouring, recontouring or reconditioning device for leading or trailing edges of airfoils used in a variety of industrial applications. The tool comprises a housing having an airfoil pathway. A grinding wheel disposed along the pathway has a desired profile shape of an airfoil edge. A guide bearing follows the edge of the airfoil and limits motion of the grinding wheel in a first dimension. An edge guide allows motion of the airfoil relative to the grinding wheel through a second dimension. 
         [0003]    According to at least one exemplary embodiment, the contouring tool is a handheld device. 
         [0004]    According to at least one exemplary embodiment, the contouring tool comprises a motor to drive the grinding wheel. 
         [0005]    According to at least one exemplary embodiment at least one edge guide is moveable. 
         [0006]    All of the above outlined features are to be understood as exemplary only and many more features and objectives of the invention may be gleaned from the disclosure herein. Therefore, no limiting interpretation of this summary is to be understood without further reading of the entire specification, claims, and drawings included herewith. 
     
    
     
       BRIEF DESCRIPTION OF THE ILLUSTRATIONS 
         [0007]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the contouring tool will be better understood by reference to the following description of embodiments taken in conjunction with the accompanying drawings, wherein: 
           [0008]      FIG. 1  is a perspective view of one embodiment of a contouring tool. 
           [0009]      FIG. 2  is an exploded perspective view of the exemplary embodiment of the contouring tool. 
           [0010]      FIG. 3  is a side view of the engagement of an airfoil passing through the exemplary contouring tool wherein an airfoil edge is engaging the grinding wheel. 
           [0011]      FIG. 4  is a side section view of an edge of an airfoil. 
           [0012]      FIG. 5  is a section view of a grinding wheel having the preselected shape of the desired airfoil. 
           [0013]      FIG. 6  is an upper perspective view of the contouring tool depicted with an end plate removed to depict the guides therein. 
           [0014]      FIG. 7  is a section view of the contouring tool showing embodiments of the various guides bearings, edge guides, and grind wheel. 
           [0015]      FIG. 8  is an exemplary graph depicting an eroded airfoil edge which falls outside acceptable tolerances. 
           [0016]      FIG. 9  is an exemplary graph depicting the contoured airfoil edge of  FIG. 8  after contouring. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Referring initially to  FIGS. 1 through 9 , embodiments of a contouring tool are shown and described wherein the tool may be utilized to contour an edge, for example leading edge, of an airfoil, which typically erodes due to exposure to dirt, water and air over time which all erode the desired shape of the airfoil over time. The terms contouring and recontouring are used interchangeably as it should be understood from this disclosure that the tool may be used for both new airfoil edge contouring or recontouring of an existing airfoil edge. Further the term leading edge is used thought this disclosure and is descriptive of merely one type of airfoil edge which may be contoured. Trailing edges may also be contoured and are within the scope of this disclosure as well. Thus the term leading should not be considered limiting but merely exemplary. 
         [0018]    Referring initially to  FIG. 1 , a perspective view of the contouring tool  10  is depicted. The structure includes a handle  12  and a housing or cover  14 . The tool  10  may be handheld or alternatively may be non-handheld such as attached to a fixture, jig or a robot, all of which being non-limiting examples. The instant embodiment utilizes a motor (not shown) in the handle  12  and a right angle drive structure operably connected to the motor to drive a grinding structure, such as a grinding wheel,  40 . A main drive shaft  42  ( FIG. 2 ) is perpendicular to the motor axis (not shown) and the main drive shaft transmits rotation from the motor to the grinding wheel  40 . Although this structure is shown and described, a right angle drive is not necessary for use of this invention and alternative embodiments may be used. Thus, the embodiment described herein should not be considered limiting. Additionally, the description of a driven grinding structure should not be considered limiting as stationary or non-driven grinding structures are also believed to be within the scope of the instant invention. 
         [0019]    The housing  14  includes a chuck access  16  wherein a chuck  18  is positioned. The chuck  18  provides a drive connection between the motor (not shown) and the drive shaft  42  of the grinding wheel, described further herein. The housing  14  includes an airfoil pathway  20  wherein various guides and the grinding structure are positioned. An airfoil  92  ( FIG. 4 ) is positioned within the pathway  20  and positioned by the guides so that the exemplary airfoil edge  94  ( FIG. 4 ) is ground to the proper shape and at the proper location of the airfoil. 
         [0020]    A clearance C is represented as a distance between guide bearings  50 ,  52 . The guide bearings  50 ,  52  inhibit rocking or side-to-side motion of the edge  94  within the pathway  20  and additionally inhibit use of the tool with airfoil which are of too large a size for the tool  10 . The guide bearings may be fixed, spring loaded or otherwise biased, adjustable or any combination thereof to accommodate multiple sizes and shapes of airfoils. 
         [0021]    Referring now to  FIG. 2 , the contouring tool  10  is shown in an exploded perspective view for identification and explanation of the multiple guides, bearings and at least one grinding wheel utilized therein. Adjacent handle  12  is an actuator  22  which actuates the motor (not shown). The motor may be various types of driving mechanisms including, but not limited to, electric motor, hydraulic motor, or pneumatic motor. The motor drives a grinding structure  40 , such as for example a grind wheel  40 , and a transmission  24  including the chuck  18 . The chuck  18  operably connects a drive shaft  42  to the grind wheel  40 . The grind structure  40  may have an RPM in the range of between 0 and 20,000 revolutions per minute (RPM). Accordingly, the motor may have a range of between 0 and 20,000 RPM with a transmission suited to provide the desired speed or RPM at the grinding wheel  40 . At an upper end of the handle, the chuck  18  and transmission may be at least partially covered by the housing  14  and a housing plate  26 . It should be understood that the housing may or may not include a portion that defines at least some portion of the handle  12 . The housing or cover  14  provides access by way of the chuck access  16  to the chuck  18  for connection or disconnection of the main drive shaft  42  to the motor within the handle  12 . The housing  14  includes a drive shaft passage  28  allowing connection or engagement with the chuck  18 . 
         [0022]    The grinding structure  40  may be formed of a tool steel or other high strength metal with a cubic boron nitride abrasive material. However, other materials may be utilized and the exemplary materials should not be considered limiting. The airfoils may be formed of titanium and alternatively may be formed of specialty alloys, such as an austenitic nickel-chromium-based alloy which is sold under the trade name INCONEL. Other non-metallic airfoils may be utilized with the tool and any reference to an airfoil should not be considered limited to metallc structures. 
         [0023]    Moving to the right-hand side of the figure, the main drive shaft  42  is shown with broken line extending to the chuck  18 . Adjacent the main shaft  42  is a first mounting plate  44  having apertures for multiple fasteners and shaft aperture allowing passage of the drive shaft  42 . The mounting plate  44  includes aperture  46  for positioning of block  48  therethrough. The block  48  is a mount for the guide bearing  50 . Adjacent the bearing block  48  is a second mounting plate  60 . The second mounting plate  60  includes a block aperture corresponding in position to the aperture  46  and allowing a portion of the block  48  to pass therethrough so that the guide bearing  50  is exposed to pathway  20 . Opposite a center spacer  62  are opposed third and fourth mounting plates  70 ,  72  and an opposed cover plate  74 . These structures attach to the housing  14  and define the pathway  20 . 
         [0024]    The guide bearings  50 ,  52  are oriented so that pivot shafts  56 ,  58  are substantially transverse to the drive shaft  42  of the grinding wheel  40 . The guide bearing  50 ,  52  position the airfoil laterally within the airfoil pathway  20  ( FIG. 1 ) and limit or inhibit movement in the axial direction of the main driveshaft  42 , as well as locking or pivoting motion along the upper edge of the airfoil  92  where a grinding may occur. The guide bearings  50 ,  52  may both be fixed or alternatively one or both bearings  50 ,  52  may be movable to vary with varying widths of airfoils. 
         [0025]    Referring above the center spacer  62  are airfoil edge guides  80 ,  82 , for example leading edge guides. The airfoil edge guides  80 ,  82  allow motion in a direction which is generally transverse to the drive shaft  42  and travel along the edge of the airfoil  92 . The guides  80 ,  82  have pivot axes which are parallel to the main drive shaft  42 . Thus, the axes of the airfoil edge guide  80 ,  82  are parallel to the axis of the grinding wheel  40 . The guides  80 ,  82  define two points along the airfoil edge of the airfoil  92  between which the grinding wheel  40  is contouring or recontouring at any moment during operation. Access to guide bearings  50 ,  52  limit motion in a first dimension and airfoil edge guides  80 ,  82  allow for motion in a second dimension generally perpendicular there the first dimension. One of the edge guides  80 ,  82  is designed to float or move to allow for some rocking motion of the grinding wheel  40  in the direction of the airfoil edge while moving along the edge  94  of the airfoil  92 . However, such rocking motion is not considered to be limiting as both edge guides  80 ,  82  may be fixed and therefore inhibiting such rocking motion. 
         [0026]    Referring now to  FIG. 3 , an exemplary edge  94  of an airfoil  92  is shown in section as indicated by the cross-hatch in the view. The tool  10  moves into or out of the page, in the view depicted. The grinding wheel  40  is shown having a central profile  90  which matches the desired or preselected shape of the airfoil. More specifically, the edge  94  of the airfoil  92  is disposed within the profile  90  of the grinding wheel  40  to grind the edge  94  as the tool passes there along. According to the instant embodiment the grinding wheel  40  is formed of two wheels which are placed together in order to form the airflow profile. The grinding wheel  40  may alternatively be formed of a single grinding wheel structure having the desired profile showed therein or may be formed to more pieces which are joined together along the drive shaft  42  ( FIG. 2 ) in order to provide the preselected airfoil edge shape. 
         [0027]    The exemplary airfoil  92  is shown with a camber or twist causing one side of the airfoil to appear wider than the other. As seen in this view, the guide bearing  50 ,  52  limit motion or pivoting at the edge  94  of the airfoil  92  so that the edge shape is not inappropriately ground in an undesired location of the airfoil  92 . 
         [0028]    As also shown in  FIG. 3 , the further guide wheel  82  is positioned over the edge  94  such that the grinding wheel  40  and profile  92  form the preselected airfoil shape on the edge thereof. The edge guide  82  allows for motion into the page while the guide bearing  50 ,  52  limit motion in a transverse direction. 
         [0029]    Referring now to  FIG. 4 , a section view of a turbine engine airfoil  92  is depicted. The shape of the airfoil  92  is after the tool  10  is used and the eroded areas are removed by way of the grinding wheel  40  and profile  90  therein. 
         [0030]    Referring now to  FIG. 5 , a section view of the exemplary grinding structure  40  is depicted comprising a first portion  87  and a second portion  88 . Alternate embodiments should be considered within the scope of the embodiments wherein the grinding wheel  48  is formed of a single piece rather than the two or more portions. A profile  90  extends about the axis of the grind wheel  40  and an aperture extends through the grinding wheel  40  for positioning of the drive shaft  40  therethrough. The grinding wheel  40  rotates about this shaft  42  and shaft aperture. The profile  90  may be symmetrical or non-symmetrical depending on the airfoil edge shape needed. 
         [0031]    Referring now to  FIG. 6 , the contouring tool  10  is shown in an upper perspective view. With cover plate  74  removed, the edge guides  80 ,  82 , the grinding wheel  40  and the guide bearings  50 ,  52  are easily visible adjacent the center spacer  62 . Disclosed in this view, the airflow will be positioned within the pathway or passage  20  between the guide bearings  50 ,  52 . These bearings inhibit movement to the left or right, as shown in the figure. The edge guides  80 ,  82  ride along the edge, for example, leading edge  94  of the airfoil  92  ( FIG. 4 ) and the edge  94  of the airfoil is positioned in the grinding profile  90  of the grinding structure  40  so that the airfoil  92  conforms to the profile  90  shape placed therein. Thus, it should be understood that the preselected shape of the profile  90  may be duplicable to a specific airfoil or multiple airfoils by merely adjusting the guides, bearings and grinding structure. However, whatever shape is desired should be applied to the proper or corresponding airfoil.  FIG. 6  further depicts a floating block  36  which retains ends of shafts  86  and which allows the edge guide  82  to move. The movement allows for some limited rocking motion by the tool  10  during movement along the edge  94  of the airfoil  92  in a direction extending between the edge guides  80 ,  82 . In operation, the edge guide  82  will move toward or away from the center spacer  62  when the rocking motion occurs while shaft  84  and guide  80  remain fixed. Alternatively, the block  36  may be fixed so that shaft  86  cannot move and edge guide  82  is also fixed inhibiting the rocking motion. 
         [0032]    Referring now to  FIG. 7 , the floating blocks  36 ,  38  are shown and depict adjacent material sectioned for the clear perspective view. A slot  34  is positioned in the mounting plate  60 ,  72 . The slot  34  allows vertical movement of the floating blocks  36 ,  38  so that shaft  86  can move in the directions shown by the arrows on the floating blocks  36 ,  38 . As shown in the figure, the pathway  20  allows for positioning upwardly through pathway  20  between the guide bearing  50 ,  52  and into the adjacent grinding wheel  40 . The airfoil edge  94  is positioned in the edge guides  80 ,  82  and the, for example, leading edge may be moved in the direction into or out of the page while the grinding wheel rotates and grinds the edge  94  of the airfoil  92  therein. The guide bearings  50 ,  52  inhibit left right motion or rocking motion along the edge of the airfoil so that the guide bearing  50 ,  52  limits motion in a first direction and the edge guides allow motion in a substantially transverse direction. 
         [0033]    Referring now to  FIGS. 8 and 9 , first and second graphs are shown comparing an airfoil edge profile prior to grinding and subsequent to grinding with the contouring tool, respectively. These graphical representations depict the change in shape of the edge due to erosion and due to use of the re-contouring tool. In  FIG. 8 , a first line  110  represents a minimum tolerance of the shape of the airfoil edge. A second parallel line  120  represents a maximum tolerance. A third broken line  122  depicts a nominal shape for an airfoil edge. A fourth line  124  indicates the flattened or otherwise misshaped portions where erosion has taken a detrimental toll on the shape of the edge. This results in loss of proper shape and decreased engine thrust for aircraft engines despite periodic overhauls of the engine structure. 
         [0034]    Following use of the exemplary embodied tool  10 , and with reference to  FIG. 9 , the line  124  representing the shape of the edge  94  more closely matches the nominal shape of line  122 . As a result, the shape of the edge is within the minimum and maximum tolerances  110 ,  120  and more closely approximates the nominal desired shape. As a result, the thrust provided by this contoured or recontoured airfoil will be increased as opposed to that in  FIG. 8  due to the erosion damage. 
         [0035]    While multiple inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the invent of embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure. 
         [0036]    Examples are used to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the apparatus and/or method, including making and using any devices or systems and performing any incorporated methods. These examples are not intended to be exhaustive or to limit the disclosure to the precise steps and/or forms disclosed, and many modifications and variations are possible in light of the above teaching. Features described herein may be combined in any combination. Steps of a method described herein may be performed in any sequence that is physically possible. 
         [0037]    All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms. The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. 
         [0038]    It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited. 
         [0039]    In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.