Abstract:
A fitting for connecting tubular assemblies according to an exemplary aspect of the present disclosure includes, among other things, a base member defining a first bore configured to receive a tube therein. A retaining band defines a second bore for receiving a portion of the base member. The retaining band defines an engagement feature on a radially outward surface configured to engage a locking mechanism of a fastening member.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/775,994 filed on Mar. 11, 2013. Cross reference is made to copending U.S. application Ser. No. 12/323,972 entitled “FERRULE.” 
     
    
     BACKGROUND 
       [0002]    This disclosure relates to tube assemblies, and more particularly to tube assemblies for aerospace and gas turbine engine applications. 
         [0003]    Tube assemblies generally include at least one fitting for fastening or joining two tubes to each other. Common types of fittings include ferrules, elbows, t-connectors and union crosses. Fittings used for joining tubes are commonly made of metal and are engaged by a locking mechanism, such as a nut. When a fitting joins two tubes, one tube mechanically attaches to an end of the fitting and the other tube usually requires a coupling device to secure to the other end of the fitting. 
         [0004]    Fittings used in aerospace applications also typically require a locking mechanism to ensure the nut stays engaged to the fitting and does not unintentionally loosen (due to vibrations, wear or other causes). One type of locking mechanism includes a lockwire. Lockwire is a braided wire that may be connected to the fitting and to a nut and/or to another object (coupling member, tube, etc.) to prevent relative rotation. The usage of lockwire generally requires additional space, and in some cases is difficult to repair or install, making lockwire ergonomically undesirable. Moreover a break in one or more of the braids of the lockwire may allow the coupling member to disengage. 
       SUMMARY 
       [0005]    A fitting for connecting tubular assemblies, according to an exemplary aspect of the present disclosure includes, among other things, a base member. The base member includes a first end and a second end, and the base member defines a first bore configured to receive a tube therein. A retaining band defines a second bore for receiving a portion of the base member. The retaining band defines an engagement feature on a radially outward surface configured to engage a locking mechanism of a fastening member. 
         [0006]    In a further non-limiting embodiment of the foregoing fitting for connecting tubular assemblies, the engagement feature includes a plurality of pockets extending radially inward and spaced circumferentially around the outward surface of the retaining band. 
         [0007]    In a further non-limiting embodiment of either of the foregoing fittings for connecting tubular assemblies, the engagement feature includes a plurality of raised protrusions extending radially outward and spaced circumferentially around the outward surface of the retaining band. 
         [0008]    In a further non-limiting embodiment of any of the foregoing fittings for connecting tubular assemblies, the engagement feature includes a plurality of raised protrusions extending radially outward and spaced circumferentially around the outward surface of the retaining band. 
         [0009]    In a further non-limiting embodiment of any of the foregoing fittings for connecting tubular assemblies, the engagement feature is symmetric about a longitudinal axis. 
         [0010]    In a further non-limiting embodiment of any of the foregoing fittings for connecting tubular assemblies, the base member defines a locating feature and the retaining band includes a key configured to be inserted into the locating feature to minimize relative rotation between the retaining band and the base member. 
         [0011]    In a further non-limiting embodiment of any of the foregoing fittings for connecting tubular assemblies, an outer surface of the base member includes a second taper extending axially inward from the second end of the base member and is configured to minimize relative axial movement between the base member and the retaining band. 
         [0012]    In a further non-limiting embodiment of any of the foregoing fittings for connecting tubular assemblies, the base member includes a first tubular portion located at the first end of the base member and a second tubular portion located at the second end of the base member. 
         [0013]    In a further non-limiting embodiment of any of the foregoing fittings for connecting tubular assemblies, the second tubular portion at least partially defines the engagement feature. 
         [0014]    In a further non-limiting embodiment of any of the foregoing fittings for connecting tubular assemblies, the base member includes a first material and the retaining band includes a second material different from the first material in hardness. 
         [0015]    A tubular assembly according to another exemplary aspect of the present disclosure includes, among other things, a base member. The base member includes a first end and a second end. The base member defines a first bore configured to receive a tube therein. A retaining band defines a second bore for receiving a portion of the base member. The retaining band defines an engagement feature on a radially outward surface. A coupling member is configured to connect to a second tube. A fastening member defines a third bore for receiving a portion of the coupling member. The fastening member includes a locking mechanism configured to engage the engagement feature of the retaining band to minimize relative rotation between the fastening member and the retaining band. 
         [0016]    In a further non-limiting embodiment of the foregoing tubular assembly, the engagement feature includes a plurality of pockets extending radially inward and spaced circumferentially around the outward surface of the retaining band. 
         [0017]    In a further non-limiting embodiment of either of the foregoing tubular assemblies, the engagement feature includes a plurality of raised protrusions extending radially outward and spaced circumferentially around the outward surface of the retaining band. 
         [0018]    In a further non-limiting embodiment of any of the foregoing tubular assemblies, the engagement feature includes a plurality of raised protrusions extending radially outward and spaced circumferentially around the outward surface of the retaining band. 
         [0019]    In a further non-limiting embodiment of any of the foregoing tubular assemblies, the engagement feature is symmetric about a longitudinal axis. 
         [0020]    In a further non-limiting embodiment of any of the foregoing tubular assemblies, the base member defines a locating feature and the retaining band includes a key configured to be inserted into the locating feature to minimize relative rotation between the retaining band and the base member. 
         [0021]    In a further non-limiting embodiment of any of the foregoing tubular assemblies, an outer surface of the base member includes a second taper extending axially inward from the second end of the base member and is configured to minimize relative axial movement between the base member and the retaining band. 
         [0022]    In a further non-limiting embodiment of any of the foregoing tubular assemblies, the base member includes a first tubular portion located at the first end of the base member and a second tubular portion located at the second end of the base member. 
         [0023]    In a further non-limiting embodiment of any of the foregoing tubular assemblies, the second tubular portion at least partially defines the engagement feature. 
         [0024]    In a further non-limiting embodiment of any of the foregoing tubular assemblies, the base member includes a first material and the retaining band includes a second material different from the first material in hardness. 
         [0025]    A method of assembling a fitting for tubular assemblies according to another exemplary aspect of the present disclosure includes, among other things, connecting a retaining band to a base member. The retaining band defines an engagement feature on a radially outward surface. A fastening member is connected to a retaining band. The fastening member includes a locking mechanism configured to engage the engagement feature. 
         [0026]    In a further non-limiting embodiment of the foregoing method, the engagement feature and the locking mechanism are configured to minimize relative rotation between the fastening member and the retaining band. 
         [0027]    In a further non-limiting embodiment of either of the foregoing methods, the base member defines a locating feature and the retaining band includes a key configured to be inserted into the locating feature to minimize relative rotation between the retaining band and the base member. 
         [0028]    In a further non-limiting embodiment of any of the foregoing methods, the retaining band is fixedly attached to the base member. 
         [0029]    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 
         [0030]      FIG. 1A  is a perspective view of a fitting. 
           [0031]      FIG. 1B  is a cross-sectional view of the fitting of  FIG. 1A . 
           [0032]      FIG. 2A  is a perspective view of a first and second tube and the fitting of  FIG. 1A-1B . 
           [0033]      FIG. 2B  is a cross sectional view of  FIG. 2A . 
           [0034]      FIG. 2C  is a perspective view of the first and second tubes of  FIG. 2A  joined by the fitting. 
           [0035]      FIG. 2D  is a cross-sectional view of  FIG. 2C . 
       
    
    
     DETAILED DESCRIPTION 
       [0036]      FIG. 1A  illustrates a perspective view of a fitting  10  for a tubular assembly.  FIG. 1B  is a cross-sectional view of the fitting  10 . In this embodiment, the fitting  10  includes a base member  12  and is shown as a ferrule. However, other fittings, connectors and couplings are contemplated including elbows, t-connectors, union crosses, reducers, and adapters. 
         [0037]    The base member  12  includes a first tubular portion  14  located at a first end  18  and a second tubular portion  16  located at a second end  22 . The base member  12  defines a first bore  15  extending between the first and second ends  18 ,  22  along a longitudinal axis A. The first tubular portion  14  may define an inner tubular groove  19  extending from the first end  18  for receiving an end of a tube. The first tubular portion  14  may also include a lip  20  at the first end  18  and may include a first taper  21  extending from the lip  20  to the second tubular portion  16 . The second tubular portion  16  may include a second taper  31  extending from the first tubular portion  14  toward the second end  22 . The second tubular portion  16  defines a conical seat  27  extending from the second end  22 . 
         [0038]    Each of the first and second tubular portions  14 ,  16  can be made of stainless steels, nickel (including alloys), titanium (including alloys) or other materials depending on requirements. Each of the first and second tubular portions  14 ,  16  can be made by machining, forging, casting or other methods depending on materials used and fitting specifications. 
         [0039]    The fitting  10  also includes a retaining band  23 . The retaining band  23  includes a generally circular configuration and defines a second bore  17  for receiving a portion of the base member  12  therein. The retaining band  23  is configured to extend at least partially from the second end  22  toward the first tubular portion  14  and about the second tubular portion  16 . However, it is contemplated that the retaining band  23  may extend any length between the first and second ends  18 ,  22 . 
         [0040]    The retaining band  23  may include a key  24  located at the proximal end  32  and extending radially inward from the second bore  17  (shown in  FIG. 1B ). The key  24  is configured to be inserted into a locating feature located on the outer surface  29  of the base member  12  for minimizing relative rotation between the retaining band  23  and the base member  12 . The locating feature as shown is a slot  25  extending from the first tubular portion  14  to the second end  22 . However, other configurations and locations of the locating feature  25  are contemplated. In another embodiment, the second tubular portion  16  and the retaining band  23  cooperate to define an interference fit to minimize relative rotation between the retaining band  23  and the base member  12 , thereby eliminating the need of a key and a locating feature. The retaining band  23  may be press fit around or molded over the base member  12 . The retaining band  23  may also be formed as a continuous piece or multiple of pieces. 
         [0041]    The retaining band  23  defines an engagement feature  26  on a radially outward surface  28  thereof. The engagement feature  26  may extend radially outward or radially inward from the outward surface  28  of the retaining band  23 . The engagement feature  26  may include a plurality of pockets  30  spaced circumferentially around the retaining band  23  and extending radially inward from the outward surface  28 . The pockets  30  may be equally spaced apart or may be spaced at unequal distances from each other. The engagement features  30  are located between a proximal end  32  and a distal end  33  of the retaining band  23 . The pockets  30  may be located closer to the proximal end  32  than the distal end  33  of the retaining band  23  to lessen stress levels in second end  22  of the base member  12 . Other sizes, shapes, number and placement of the pockets  30  are contemplated. The engagement feature  26  may include other configurations than the pockets  30 , including one or more slots, grooves, bumps or raised protrusions. In another embodiment, the engagement feature  26  includes a plurality of pockets and bumps each extending from the outward surface  28  of the retaining band  23 . The retaining band  23  also defines a shoulder  37  located near the proximal end  32 . 
         [0042]    Additionally, the retaining band  23  can be made of stainless steels, nickel (including alloys), titanium (including alloys) or other metals depending on requirements. The retaining band  23  can be made by machining, forging, casting or other methods depending on materials used and fitting specifications. The retaining band  23  may also include a material greater in hardness than the material of the base member  12 . 
         [0043]      FIGS. 2A-2B  illustrates a tubular assembly  34  in an uninstalled position. The tubular assembly  34  includes a first tube  35  and a second tube  36  to be joined together with the fitting  10 . The first tube  35  is inserted into the inner tubular groove  19  of the first tubular portion  14  (shown in  2 B and  2 D). The first tube  35  can be connected to the first tubular portion  14  by welding, brazing, inertia bonding, or by other conventional methods known in the art. In another embodiment, the first tube  35  is inserted over the lip  20 . In yet another embodiment, the first tube  35  is connected to the end  18  of the first tubular portion  14 . The second tube  36  is connected to a coupling member  38 . The second tube  36  can be connected to the coupling member  38  by welding, brazing, inertia bonding, or by other conventional methods known in the art. The coupling member  38  defines a second interface  39  located at a third end  41  configured to be received at least partially within the first bore  15  of the base member  12  and adjacent to the first conical seat  27 . 
         [0044]    The tubular assembly  34  includes a fastening member  40  for fastening the first tube  35  and the second tube  36  to each other. The fastening member  40  may be configured as a nut for being engaged by a tool. The fastening member  40  defines a third bore  42  (shown in  FIGS. 2B and 2D ) for receiving a portion of the base member  12  and the retaining band  23  therein. 
         [0045]    The fastening member  40  is moveable along longitudinal axis A to expose at least a portion of the second tubular portion  16 . The retaining band  23  may be configured to prevent the fastening member  40  from extending in the axial direction past the distal end  33  of the retaining band  23 . Accordingly, the fitting  10  is mostly exposed when the fastening member  40  and the coupling member  38  are disconnected ( FIGS. 2A-2B ). 
         [0046]    The fastening member  40  includes a locking mechanism  44  extending radially inward from the third bore  42 . The locking mechanism  44  may be a spring loaded part or any other part configured to engage the pockets  30  to secure the retaining band  23  to the fastening member  40 . To allow for a smooth retraction of the fastening member  40  from the retaining band  23 , the pockets  30  may be configured with an arcuate profile extending along the longitudinal axis A. The arcuate profile reduces the amount of force required to pull the locking mechanism  44  from the pockets  30  and allows for easier disassembly of the fastening member  40  from the retaining band  23 . Additionally, the tension of the spring of the locking mechanism  44  may be configured to resist disengagement from the pockets  30 , thereby minimizing axial movement of the fastening member  40  relative to the retaining band  23 . In another embodiment, the locking mechanism  44  is located on the retaining band  23  and the engagement feature  26  is located on the fastening member  40 . 
         [0047]    Referring to  FIGS. 2C-2D , the fastening member  40  may define a channel  46  (shown in  FIG. 2D ) extending radially inward from the third bore  42 . The fastening member  40  may also define a pair of orifices  48  for accessing the channel  46 . A thrust wire  50  may be inserted into the channel  46  through the orifices  48  to minimize axial movement of the fastening member  40  toward the second end  22 . 
         [0048]      FIGS. 2C-2D  illustrate the tubular assembly  34  in an installed position. To install the tubular assembly  34 , the fastening member  40  is moved axially toward the second end  22  of the base member  12 , causing the locking mechanism  44  to engage the pockets  30  of the retaining band  23 . Accordingly, the locking mechanism  44  and the pockets  30  cooperate to minimize relative rotation of the fastening member  40  and the retaining band  23 . 
         [0049]    Thereafter, the coupling member  38  is inserted partially into the third bore  42  of the fastening member  40 . The coupling member  38  includes a plurality of first threads  52  configured to engage a corresponding plurality of second threads  54  of the fastening member  40  when the coupling member  38  is rotated about the longitudinal axis A relative to the fastening member  40 . The locking mechanism  44  and the pockets  30  cooperate to minimize relative rotation of the fastening member  40  about the longitudinal axis A while the coupling member  38  and the fastening member  40  are connected. In another embodiment, the locking mechanism  44  is configured to allow relative rotation of the fastening member  40  with respect to the retaining band  23  to secure the fastening member  40  to the coupling member  38 . 
         [0050]    After the coupling member  38  is connected to the fastening member  40 , the thrust wire  50  is inserted into the channel  46  through the orifices  48 . The thrust wire  50  engages the second taper  31  near the second tubular portion  16  and the shoulder  37  of the retaining band  23  to minimize axial movement of the fastening member  40 . Accordingly, the locking mechanism  44  and the pockets  30 , as well as the thrust wire  50 , ensure that the first and second threads  52 ,  54  do not loosen or back off, securely connecting the first and second tubes  35 ,  36  to each other. 
         [0051]    Although the different embodiments have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the embodiments in combination with features or components from another one of the embodiments. 
         [0052]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiments 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.