Patent Document

STATEMENT OF GOVERNMENT INTEREST 
       [0001]    The present invention was developed, at least in part, with government funding, under Contract No. N00019-02-C-3003 awarded by the United States Navy. The U.S. Government has certain rights in this invention. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to nosecone assemblies for gas turbine engines, and more particularly to baffles for use with gas turbine engine nosecone assemblies. 
         [0003]    Gas turbine engines, such as those for aerospace applications, generally include a nosecone. The nosecone can be static (i.e., non-rotating) or rotating. Nosecones are frequently attached to supporting structures of the gas turbine engine by way of bolts in order to facilitate removal of the nosecone for repair and maintenance. However, it is desirable to have not fasteners extending into a flowpath at the nosecone. 
         [0004]    The present invention provides an alternative configuration for a nosecone bolt access and aerodynamic leakage baffle. 
       SUMMARY 
       [0005]    A device includes a resilient member having a first end for blocking an access hole and a second end for attachment to a support surface, an opening extending through the resilient member and located between the first and second ends, and a bolt connection location positioned at the second end of the resilient member. The first end of the resilient member blocks the access hole and can be deflected to provide tool access to the bolt connection location through the first opening. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a baffle according to the present invention. 
           [0007]      FIG. 2  is a perspective view of the baffle of  FIG. 1  installed on a gas turbine engine nosecone. 
           [0008]      FIG. 3  is a cross-sectional view of the gas turbine engine nosecone and baffle with a tool inserted into the nosecone. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]      FIG. 1  is a perspective view of a baffle (or device)  10  for use with a gas turbine engine nosecone. In the illustrated embodiment, the baffle  10  includes an elongate extension  12 , a flange portion  14 , an elongate access opening  16 , a pair of scallops  18 A and  18 B, and four fastener openings  20  (only two being visible in  FIG. 1 ). The baffle  10  can be formed of a metallic material, such as stainless steel, a composite material, such as reinforced carbon fiber, etc. 
         [0010]    The elongate extension  12  extends from the flange portion  14 , and can be integrally formed with the flange portion  14 . The elongate extension  12  defines opposed lateral edges  22 A and  22 B and a radiused distal end  24 . The distal end  24  is located opposite the flange portion  14 . The elongate access opening  16  extends through both the elongate extension  12  and through the flange portion  14 , and is positioned approximately midway between the opposed lateral edges  22 A and  22 B of the elongate extension  12 . The elongate access opening  16  has a width sufficient to accommodate tooling (e.g., a wrench) inserted therethrough. A bolt access seal portion  26  of the baffle  10  is defined between the distal end  34  and the elongate access opening  16  in a curved portion of the elongate extension  12 . 
         [0011]    The pair of scallops  18 A and  18 B are located along the lateral edges  22 A and  22 B, respectively, of the elongate extension  12 , and can be posited adjacent to the elongate opening  16 . In the illustrated embodiment, both of the scallops  18 A and  18 B have an identical radiused configuration and are located in a non-curved portion of the elongate extension  12 . A width of the elongate extension  12  is reduced between the scallops  18 A and  18 B. The scallops  18 A and  18 B are configured to help control a stiffness of the elongate extension  12  of the baffle  10 , as explained further below. The particular configuration of the scallops  18 A and  18 B can be selected to provide suitable stiffness for a given application. 
         [0012]    The fastener openings  20  allow rivets  28  or other suitable fasteners (e.g., screws, bolts) to secure the baffle  10  to a nosecone at the flange portion  14 . The fastener openings  20  can be arranged with two openings on either side of the access opening  16 . In further embodiments, the number of fastener openings  20  and their arrangement can vary as desired for particular applications. A bolt  30  is positioned at a bolt connection location on the flange portion  14  between the two pairs of the fastener openings  20 . The bolt  30  can extend through the access opening  16  at the flange portion  14 , in other words, the bolt connection location can be defined as a portion of the access opening  16 . 
         [0013]      FIG. 2  is a perspective view of the baffle  10  installed on a gas turbine engine nosecone  40 . The nosecone  40  includes a body  42 , a plurality of mounting flanges  44  each having a bolt hole  46 , and a plurality of openings  48  in the body  42 . It should be noted that not all of the bolt holes  46  and openings  48  are visible in  FIG. 2 . The nosecone  40  can be formed of a moldable composite material, a metallic material, or other suitable materials. 
         [0014]    The body  42  defines an aerodynamic shape of the nosecone  40 , which can vary as desired for particular applications. An exterior surface of the body  42  is a boundary surface for a flowpath of air entering an annular inlet of a gas turbine engine to which the nosecone  40  is attached. The mounting flanges  44  are located at an aft circumferential edge of the body  42 , and extend radially inward toward an interior cavity defined by the body  42 . A bolt hole  46  is provided through each mounting flange  44  in order to provide attachment points for removably securing the nosecone  40  to an engine with bolts or other suitable fasteners. The mounting flanges  44  can be formed integrally with the body  42  of the nosecone  40 . In the illustrated embodiment, seven circumferentially spaced mounting flanges  44  are provided, though the number and arrangement of the mounting flanges  44  can vary in further embodiments. 
         [0015]    The openings  48  are provided through the body  42  of the nosecone  40  at locations circumferentially or azimuthally aligned with each of the bolt holes  46  in the flanges  44 . More particularly, the openings  48  are aligned (i.e., coaxial) with a central axis of each corresponding bolt hole  46  (a number of exemplary axes are shown in  FIG. 2  for illustrative purposes). The openings  48  provide access through the body  42  of the nosecone  40  for tooling (e.g., a wrench) to tighten or loosen bolts  30  through the bolt holes  46 , for attaching or removing the nosecone  40  relative to an engine. 
         [0016]    The baffle  10  is connected to one of the flanges  44  by the rivets  28  such that the elongate extension  12  of the baffle  10  is positioned along an interior surface of the cavity defined by the body  42  of the nosecone  40 . The elongate extension  12  and the flange portion  14  of the baffle  10  meet adjacent to the interior surface of the nosecone  40 . The elongate extension  12  of the baffle  10  includes at least a portion near the distal end  24  with a curvature that corresponds to an aerodynamic curvature of the body  42  of the nosecone  40 , and more particularly to a curvature of the interior surface of the body  42  of the nosecone  40 . Stiffness of the baffle  10  keeps the elongate extension  12  in contact with the interior surface of the body  42  of the nosecone  40  by default. 
         [0017]    The bolt access seal portion  26  on the elongate extension  12  of the baffle  10  is positioned at the corresponding opening  48  in the body  42  of the nosecone  40 . The bolt access seal portion  26  is configured to have a surface area at least as large as an exposed area of the opening  48 . In this way, the bolt access seal portion  26  covers and aerodynamically seals the opening  48  to create a positive and negative pressure seal in order to limit the entry of air and ice into the cavity of the nosecone  40  during engine operation. In order to maintain aerodynamic sealing of the opening  48 , the baffle  10  should have sufficient stiffness, which is determined as a function of baffle materials and baffle geometry (including configuration of the scallops  18 A and  18 B). In the event of liberation of a component within the cavity of the nosecone  40 , such as liberation of a bolt  30 , coverage and sealing of the opening  48  by the bolt access seal portion  26  of the baffle  10  also helps prevent such a liberated object from exiting the cavity and being ingested by the engine, thereby reducing a risk of domestic object damage (DOD) to engine components. In other words, the baffle  10  helps protect the engine by trapping liberated objects within the cavity of the nosecone  40  until the liberated objects can be removed by maintenance personnel. 
         [0018]    Although only one baffle  10  is shown in  FIG. 2 , one baffle  10  would generally be provided for each opening  48  in the body  42  of the nosecone  40 . 
         [0019]      FIG. 3  is a cross-sectional view of the baffle  10  installed on the gas turbine engine nosecone  40 , showing a tool  50  (e.g., a wrench for a Robertson, hex/Allen, Triple Square/XZN or other bolt drive) inserted into one of the openings  48  in the body  42  of the nosecone  40 . As shown in  FIG. 3 , the elongate extension  12  of the baffle  10  is resiliently deflected by the tool  50 , and the tool  50  extends through the elongate access opening  16  to engage the bolt  30  at the flange portions  14  and  46  of the baffle  10  and nosecone  40 , respectively. The amount of deflection of the baffle  10  is a function of the stiffness provided by the scallops  18 A and  18 B (not visible in  FIG. 3 ) and the material from which the baffle  10  is made, as well as the location of the elongate access opening  16 . When the tool  50  is initially inserted through the opening  48  in the nosecone  40 , the tool  50  contacts the bolt access seal portion  26  of the baffle  10 . Force applied at the seal portion  26  by the tool  50  causes the elongate extension  12  of the baffle  10  to deflect. Continued application of force with the tool  50  causes the tool  50  to slide along the elongate extension  12  until passing through the elongate access opening  16  and reaching the bolt  30 . Withdrawal of the tool  50  causes the baffle  10  to return to its original position with the bolt access seal portion  26  covering the opening  48  in the nosecone  20 . 
         [0020]    It should be recognized that the present invention provides numerous advantages. For instance, the elongate access opening of the baffle allows tool access to a cavity within a nosecone with relatively little deflection of the baffle, which allows the baffle to have a relatively high stiffness to provide sealing of openings in the nosecone during engine operation and also to enhance baffle lifespan by limiting fatigue. Stiffness of the baffle can be especially important when utilized with a static (i.e., non-rotating) nosecone, where there is no centrifugal action to help maintain sealing of nosecone openings. 
         [0021]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. For instance, the dimensions and proportions of the baffle can vary as desired for particular applications.

Technology Category: 4