Abstract:
An alignment tool is used to ensure proper alignment of a component on a rotating gear relative to a non-rotating platter. The alignment tool includes a first arm member coupled to a locating feature on the gear, and a second arm member that is coupled to the first arm member such that the second arm member is movable relative to the first arm member. When the first arm member is coupled to the locating feature, the second arm member locates off the platter to verify proper alignment. The second arm member is cannot be fitted to the platter when there is improper alignment.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This disclosure relates to a homing tool for a coating platter and, more particularly, to a homing tool for a platter that supports turbine engine components for a coating process. 
         [0002]    Certain gas turbine engine components are subject to a coating application during manufacture, such as a cathodic arc coating for example. A tooling fixture is used to support multiple components such that the coating is evenly applied over all desired areas. The tooling fixture includes a fixed platter and a large central gear that rotates relative to the platter. Several tooling sites with locating features are supported on the gear. The tooling sites and the central gear are connected in such a way that rotating the central gear about its axis will also rotate the tooling sites about their axis. Shielding is attached to the platter assembly for protective purposes. The tooling fixture and associated components are placed onto the tooling sites on the central gear. The platter is placed within the coater apparatus and the coating is applied. 
         [0003]    In order to ensure that the components are fully and evenly coated, the gear must be “homed” or aligned properly. If the gear is not aligned properly prior to the coating process, then the tooling sites will not be in the correct position. As the cathodic arc coating process is a line of sight coating process, if the components are improperly aligned, deposition of the coating could be uneven. 
         [0004]    One example of a tool that has been used to check alignment is a locating plate. To check whether there is proper alignment, the shielding is removed and then the locating plate is bolted into place. The locating plate includes three holes. One hole is to be aligned with a hole in the gear, and the other two holes are to be aligned with two holes in the platter. If all of the corresponding holes are in alignment with each other, then the platter is supposedly homed. However, if the gear has been rotated 180 degrees, the locating plate will still fit on the platter and the gear but the homing is incorrect and the tooling sites and thus the components are not in the correct position on the gear. 
         [0005]    Another disadvantage with the use of the locating plate is that the shielding must be removed prior to attachment of the locating plate. As such, this homing operation cannot be accomplished between coating runs due to the high heat that the tooling fixture components are subjected to during the coating process. To perform the homing operation, the tooling fixture components need to cool sufficiently such that all of the shielding can be removed, then the platter is removed from the coating machine, and then the locating plate is mounted to the platter and the gear to check for alignment. This alignment check process could take over 30 minutes to perform. 
         [0006]    Accordingly, there is a need for a method and apparatus to check for proper alignment that addresses the problems identified above. 
       SUMMARY OF THE INVENTION 
       [0007]    An alignment tool is used to ensure proper alignment of a tooling site on a rotating gear relative to a non-rotating platter. In one example, at least one component is associated with each tooling site on the gear to receive a coating application. 
         [0008]    The alignment tool includes a first arm member coupled to a locating feature associated with the tooling site on the gear, and a second arm member that is coupled to the first arm member such that the second arm member is pivotable relative to the first arm member. When the first arm member is coupled to the locating feature, the second arm member is pivoted to locate off of the platter to verify proper alignment of the tooling site. The second arm member cannot be fitted around a front feature found on a front portion of the platter or underneath a bottom surface when there is improper alignment. 
         [0009]    In one example, the first arm member and the second arm member are coupled together with a hinge connection. 
         [0010]    In one example, the first arm member includes a socket that is coupled to the locating feature, and the second arm member includes first and second arms that are fitted underneath the platter to verify alignment. 
         [0011]    A method for verifying alignment includes the steps of coupling the first arm portion to the locating feature for the tooling site on the rotating gear, pivoting the second arm portion relative to the first arm portion to locate off a bottom surface of the platter, and identifying proper alignment of the tooling site when the second arm portion is fitted underneath the platter and around the front feature. Improper alignment of the tooling site can be identified when the second arm portion will not fit underneath the platter and around the front feature. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows. 
           [0013]      FIG. 1  is a schematic representation of an alignment tool for a tooling fixture. 
           [0014]      FIG. 2  shows an initial step for verifying alignment. 
           [0015]      FIG. 3  shows an intermediate step for verifying alignment. 
           [0016]      FIG. 4  shows a final step for verifying alignment. 
           [0017]      FIG. 5  shows the alignment tool in a final installation position. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]      FIG. 1  shows a platter  10  that comprises a non-rotating structure having an upper surface  12  and a lower surface  14 . A recess  16  is formed within the upper surface  12 . A gear  18  is received within the recess  16  for rotation about an axis A. 
         [0019]    The gear  18  includes a gear body with an upper surface  20  having a plurality of tooling sites  22  that are to receive tooling fixtures  70  that contain and mask a component  72  for a coating application. In one example, the components  72  comprise turbine engine components. A main locating pin  26  and a secondary locating pin  68  are associated with each tooling site  22 , with both locating pins  26 ,  68  being associated with at least one of the tooling fixtures  70 . A plurality of gear teeth  28  are formed about an outer circumference of the gear body. 
         [0020]    During a coating application for the engine components, a mechanism (not shown) drives the gear teeth  28  to rotate the tooling sites  22  and the associated components  72  such that a coating can be fully and evenly applied to desired areas. In one example, the platter  10 , gear  18 , and associated components  72  are subjected to a cathodic arc coating process. The cathodic arc coating process is a well known process and will not be discussed in further detail. 
         [0021]    As known, cathodic arc coating is a line of sight coating process so it is important that the rotating gear  18  with its associated tooling sites  22  be aligned or “homed” properly relative to the non-rotating platter  10 . To verify proper alignment, the gear  18  is first rotated around is axis A so that a particular tooling site  22  is in a front middle position. An alignment tool  30  is coupled with a locating feature for this tooling site  22 , i.e. pins  26  and  68 , and a front locating feature  24  on a front of the platter  10 . 
         [0022]    As shown in  FIG. 1 , the alignment tool  30  includes a first arm portion  32  that is associated with one set of locating pins  26 ,  68  and a second arm portion  34  that is pivotally mounted to the first arm portion  32 . Although a pivotal connection is shown, it should be understood that other types of connections that allow relative movement between the first  32  and second  34  arm portions could also be used. In one example, the second arm portion  34  is coupled to the first arm portion  32  with a hinge connection  36 . The second arm portion  34  includes first  38  and second  40  arms that are located off the lower surface  14  of the platter  10 . When the locating pins  26 ,  68  are properly aligned relative to the platter  10 , the first  38  and second  40  arms will fit around the front locating feature  24 . If the locating pins  26 ,  68  are improperly aligned, the hinged arm portion, i.e. the first  38  and second  40  arms will not fit around the front locating feature  24 . 
         [0023]    The operation of the alignment tool  30  is shown in greater detail in  FIGS. 2 ,  3 ,  4 , and  5 . As shown in  FIG. 2 , the first arm portion  32  includes a main socket  42  that is fitted over the main locating pin  26  and a secondary socket  74  that is fitted over the secondary locating pin  68 . As shown, the sockets  42 ,  74  are fitted onto the locating pins  26 ,  68  that are closest to the front edge of the platter  10 . Once the sockets  42 ,  74  are fitted on the locating pins  26  and  68 , the second arm portion  34  is pivoted downwardly relative to the first arm portion  32  as shown at arrow  44  in  FIG. 3 . The second arm portion  34  is pivoted downwardly so that both the first  38  and second  40  arms can be fitted or located around the front locating feature  24  as shown in  FIGS. 4 and 5 . Alternatively, platter  10  can have recesses in the side into which first  38  and second  40  arm portions can register. If the locating pins  26  and  68  are improperly aligned, the second arm portion  34  will not be able to be pivoted into the position as shown in  FIGS. 4 and 5 . 
         [0024]    As shown in  FIG. 3 , the first arm portion  32  includes a first linear body portion  50  and a second linear body portion  52  that extends transversely relative to the first linear body portion  50 . In one example, the first  50  and second  52  linear body portions are perpendicular to each other. The second linear body portion  52  includes an enlarged head portion  54  that includes the sockets  42 ,  74 . 
         [0025]    In the example shown, the locating pins  26 ,  68  are obliquely orientated relative to the upper surface  20  of the gear  18 . As such, a distal end surface  56  of the enlarged head portion  54  is tapered to facilitate insertion onto the locating pins  26 ,  68 . When the socket  42  is fitted over the locating pins  26  and  68 , the first linear body portion  50  is generally parallel to the upper surface  20  of the gear  18  with the second linear body portion  52  extending downwardly toward the upper surface  20 . 
         [0026]    As shown in  FIG. 3 , the second arm portion  34  includes a first linear body portion  60  and a second linear body portion  62  that extends transversely relative to the first linear body portion  50 . In one example, the first  60  and second  62  linear body portions are perpendicular to each other such that the second arm  34  portion has a T-shape. The second linear body portion  62  includes first  64  and second  66  opposing ends. The first arm  38  of the second arm portion  34  extends transversely relative to the first opposing end  64  and the second arm  40  extends transversely relative to the second opposing end  66 . In this example configuration, the second linear body portion  62  and the first  38  and second  40  arms cooperate to form a C-shape. 
         [0027]    When the sockets  42 ,  74  are fitted over the locating pins  26  and  68 , and when the second arm portion  34  is pivoted to the position shown in  FIGS. 4 and 5 , the first linear body portion  50  of the first arm portion  32  is generally perpendicular to the first linear body portion  60  of the second arm portion  34 . Also as shown in  FIGS. 4 and 5 , when in a proper alignment position, the first  38  and second  40  arms are generally parallel to the first linear body portion  50  of the first arm portion  32 . 
         [0028]    The example alignment tool  30  can verify alignment in a significantly shorter amount of time than with prior homing or alignment tools because the platter does not have to be removed from the coater apparatus and the shielding does not have to be removed. Further, the platter  10  is homed off of the position of the locating pins  26 ,  68  for the tooling sites  22  as opposed to a location of the gear, which eliminates the possibility of misalignment or homing error. 
         [0029]    Once properly aligned, tooling fixtures  70  that contain and mask the components  72  can then be positioned at each tooling site  22  such that the components  72  can be coated. Each tooling fixture  70  includes sockets  80 ,  82  ( FIG. 1 ) that receive the locating pins  26 ,  68  at the tooling sites  22  to support the tooling fixture  70 . 
         [0030]    Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments. 
         [0031]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.