Abstract:
A hanger assembly for use between a first duct and a second duct has a flexible leaf spring having a body and a leg, a locking member for attaching the leg to the first duct, and a mounting member for attaching the body to the second duct.

Description:
BACKGROUND 
     A gas turbine engine typically includes a fan section, a compressor section, a combustor section, a turbine section, and in some configurations an augmenter section. A liner extending aft of the turbine section typically referred to as an exhaust or augmenter liner includes an inner liner exposed to hot exhaust gases. The inner liner is typically spaced from an outer structure with a plurality of hanger assemblies. The hanger assemblies are required to accommodate misalignment, complex shapes, large thermal growth differentials, significant pressure loads and high temperatures. Moreover, the hangers are positioned within a confined physical envelope that is difficult to access while accommodating relative movement within several planes simultaneously. 
     Accordingly, it is desirable to design and develop a reduced cost hanger that performs as desired in the harsh environment of the exhaust duct while also simplifying assembly and reducing cost. 
     SUMMARY 
     According to an embodiment disclosed herein, a hanger assembly for use between a first duct and a second duct includes a flexible leaf spring having a body and a leg, a locking member for attaching the leg to the first duct, and a mounting member for attaching the body to the second duct. 
     According to any prior embodiment disclosed herein, the body includes a circular portion extending therefrom. 
     According to any prior embodiment disclosed herein, the body has an opening therein cooperating with a stud extending from the second duct. 
     According to any prior embodiment disclosed herein, a first portion of the leg extends from the body at an inner obtuse angle. 
     According to any prior embodiment disclosed herein, a second portion of the leg extends from the first portion of the leg at an inner acute angle. 
     According to any prior embodiment disclosed herein, a third portion of the leg extends from the second portion of the leg at an outer acute angle. 
     According to any prior embodiment disclosed herein, the locking member includes a cover, a first flange formed upon the cover and extending from cover towards the body and a second flange extending from the first flange at an outer obtuse angle, wherein the first flange and the second flange capture the leg. 
     According to any prior embodiment disclosed herein, the leg has a portion disposed at an acute angle, such portion captured by the first flange and the second flange wherein the acute angle and the obtuse angle are complementary to each other. 
     According to any prior embodiment disclosed herein, the second flange is wider than the portion. 
     According to a further embodiment disclosed herein, a gas turbine engine includes a fan section including a plurality of fan blades rotatable about an axis; a compressor section in communication with the fan section; a combustor in fluid communication with the compressor section; a turbine section in fluid communication with the combustor and driving the fan section and the compressor section; and an exhaust liner aft of the turbine section, the exhaust liner including a liner defining an inner surface exposed to exhaust gases, a duct spaced radially outward of the liner; and a hanger assembly supporting the liner relative to the duct, the hanger assembly including a flexible leaf spring having a body and a leg, a locking member attaching the leg to the duct; and a mounting member attaching the body to the liner. 
     According to any prior embodiment disclosed herein, a first portion of the leg extends from the body at an inner obtuse angle, wherein a second portion of the leg extends from the first portion of the leg at an inner acute angle and wherein a third portion of the leg extends from the second portion of the leg at an outer acute angle. 
     According to any prior embodiment disclosed herein, the locking member includes a cover disposed outside of the casing, a first flange formed upon the cover and extending from cover towards the body and a second flange extending from the first flange at an outer obtuse angle, wherein the first flange and the second flange capture the leg. 
     According to any prior embodiment disclosed herein, the leg has a portion disposed at an acute angle, such portion captured by the first flange and the second flange wherein the acute angle and the obtuse angle are complementary to each other. 
     According to a still further embodiment disclosed herein, a method of supporting a liner of a gas turbine engine includes the steps of providing a flexible leaf spring having a body and a leg, a locking member for attaching the leg to the first duct and a mounting member for attaching the body to the second duct, providing an opening in the first duct, and inserting the leaf spring through the opening. 
     According to any prior embodiment disclosed herein, the method includes the further step of arranging the leaf spring so that a thickness of the leaf spring is parallel to flow passing between the first and second ducts. 
     According to any prior embodiment disclosed herein, the method includes the further step of attaching the body of the leaf spring to a stud extending from the second duct. 
     According to any prior embodiment disclosed herein, the method includes the further step of inserting the lock member through the opening, and rotating the lock member to capture the leg between the lock member and the first duct. 
     According to any prior embodiment disclosed herein, the method includes the further step of providing a cover for covering the opening over the opening, the cover having the lock member attaching thereto, and putting the cover on the first duct such that the lock member extends through the opening without engaging the leg. 
     According to any prior embodiment disclosed herein, the method includes the further step of rotating the cover and the lock member to lock the leg between the lock member and the first duct. 
     These and other features disclosed herein can be best understood from the following specification and drawings, the following of which is a brief description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a sectional view of a gas turbine engine incorporating an embodiment of a leaf spring hanger shown herein. 
         FIG. 2  shows a side view leaf spring hanger embodiment for use in then engine of  FIG. 1 . 
         FIG. 3  shows a perspective view of a cover for use as a part of the hanger assembly as shown in  FIG. 2 . 
         FIG. 4  shows a perspective view of the leaf spring assembly as used in  FIG. 2 . 
         FIG. 5  shows a sectional, perspective view of the leaf spring hanger assembly of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a gas turbine engine  10  includes a fan section  12 , a compressor section  14 , a combustor section  16 , and a turbine section  18 . Air entering into the fan section  12  is initially compressed and fed to the compressor section  14 . In the compressor section  14 , the incoming air from the fan section  12  is further compressed and communicated to the combustor section  16 . In the combustor section  16 , the compressed air is mixed with gas and ignited to generate a hot exhaust stream  28 . The hot exhaust stream  28  is expanded through the turbine section  18  to drive the fan section  12  and the compressor section  14 . In this example, the gas turbine engine  10  includes an augmenter section  20  where additional fuel can be mixed with the exhaust gasses  28  and ignited to generate additional thrust. The exhaust gasses  28  flow from the turbine section  18  and the augmenter section  20  through an exhaust liner assembly  22 . 
     The example exhaust liner assembly  22  includes a liner  24  that defines an inner surface exposed to the hot exhaust gasses  28 . The liner  24  (e.g., a first duct) is supported by a duct  26  (e.g., a second duct) disposed radially outward of the liner  24 . An annular space  30  is disposed between the liner  24  and the duct  26  for a cooling airflow. The example exhaust liner assembly  22  includes a first section  32 , a second section  34 , and third section  36 . Each of the first, second and third sections  32 ,  34 ,  36  are movable relative to each other to provide a thrust vectoring function. As appreciated, although the gas turbine engine  10  is disclosed and described by way of example and other configurations and architectures of gas turbine engines are within the contemplation of this disclosure and would benefit from the disclosures within this application. 
     Referring to  FIG. 2  a leaf spring hanger assembly  95  is shown. A casing/outer duct  26 / 100  has a major opening  105  (see also  FIGS. 4 and 5 ) and a plurality of bolt holes  110  as will be discussed herein (See  FIG. 4 ). 
     Liner/inner duct  24 / 115  is disposed within the casing/outer duct  26 / 100 . A plurality of studs  120  are fixedly attached to the liner  115  as are known in the art (see FIGS.  2  and  5 ). A leaf spring  125  has a flat body  130  that touches the liner  115  along a length D of the flat body  130 . The flat body  130  has an orifice  135  extending therethrough (see also  FIG. 5 ) for extending around the stud  120  protruding from the liner  115 . The flat body  130  has a portion  140  ( FIG. 5 ), which may be circular, that extends around the central opening orifice  135  to provide load support of the flat body along a greater surface area of the liner  115 . The flat body  130  has a pair of integrally formed legs  145 . The legs  145  have a first bend portion  150  that forms an inner side obtuse angle α relative to the flat body portion  130 . The legs extend away from the first bend portion  150  to the second bend portion  155  that forms an inner side acute angle β, and extend to a third bend portion  160  that forms an outer side acute angle γ. The end portion  165  of each leg  145  is parallel to the casing  100  and roughly parallel to the flat body portion  130 . 
     The legs  145  have a first portion  147  between the first bend portion  150  and the second bend portion  155 , a second portion  153  between the second bend portion  155  and the third bend portion  160  and end portion  165 . The wear areas  201  that extend from second portion  153  around the third bend  160  to the third leg may be coated with a coating  207  to minimize wear on the rubbing surfaces. Alternatively portions of the first flange  190 , the second flange  195  and the casing  100  or combinations thereof may also be coated with a coating  207 . 
     Referring now to  FIG. 3 , cover  170  has a roughly elliptical body  175  having a pair of apertures  180  that align with holes  110  in the casing  100  for attachment thereto. Each of a pair of locking tabs  185  have a first flange  190  perpendicular to the body  175  and a second flange  195  extending at an outer obtuse angle Δ from the first flange  190 . The second flanges  195  extend away from each other and the first flanges  190  are in parallel to each other. The second flanges have an outer end  205  that fit within major opening  105  (see  FIG. 4 ). The outer ends  205  may be slightly smaller than a diameter of the major opening  105  to allow insertion of the cover by tilting one side of the cover  170 , inserting one of the first flanges  190  on the tilted side into the major opening  105  until the casing  100  engages the first flange  190  and then tilting another side of the cover  170  and its other flange  190  through the major opening  105 . 
     In order to construct the hanger assembly as seen in  FIGS. 4 and 5 , leaf spring  125 , which is flexible, is manipulated and compressed so its body  130  and its legs  145  fits through the major opening  105 . The orifice  135  of the leaf spring  125  is inserted over the stud  120  and then secured thereto by a nut  210 . The width of the leaf spring is arranged parallel to the flow  116  so that the narrow width of the leaf spring  125  minimizes obstructions to flow  116  passing between the casing  100  and the liner  115 . The width W 1  of the first and second flanges  190 ,  195  is greater than the width W 2  of the leaf spring  125  to accommodate any axial movement of the casing  100  relative to the liner  115  that would tend to move the leaf spring axially relative to the casing  100  so the leaf spring remains locked relative to the casing  100 . 
     After the leaf spring  125  is secured to the liner  115 , cover  170  is inserted into the major opening  105  so that the locking tabs  185  do not interfere with the leaf spring  125  (see  FIG. 4 ). Cover  170  is then rotated so that the apertures  180  align with the holes  110  and the locking tabs  185  are in parallel with the leaf spring  125  such that the third bend  160  of each leg is disposed between each locking tab  185  and the casing  100 . There may be a gap G between the legs  145  and the locking tabs  185  to allow for relative motion between the parts. The angle γ and the angle Δ are complementary (see  FIG. 2 ) so that the third bend portion  160  fits behind the locking tabs at an angle Δ such that the angle Δ and the angle γ sum up to approximately 180°. Because the major opening  105  is completely covered by the cover  170  there is minimal leakage between the cover and the casing  100 . There are very few parts involved with this assembly. 
     Thermal movement between the liner and the case is provided in all directions. The leaf spring  125  acts in tension and compression. The leaf spring  125  hardness and flexibility can be tailored for required loads and because of the tolerances built into the system no shimming or rigging is required. 
     Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.