Abstract:
A method of making a fluid coupling includes a step of providing a cylindrical stem having a fluid conduit therethrough. The method also includes a step of placing a hollow shell over a first end of the stem. The method also includes a step of die swaging the shell to the stem at an attachment location along a length of the stem, wherein the die swaging step includes forming a tool engaging hexagonal shape on an outer surface of the shell at the attachment location.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates generally to a method of making a fluid coupling, and more particularly to die forming a hexagon shape on an outer portion of a shell while joining the shell to a stem. 
       BACKGROUND 
       [0002]    Fluid couplings are used to connect a fluid line or hose to various types of industrial equipment and machinery via the equipment connection ports or manifolds. A fluid coupling typically has two ends: one end generally defines the hose connection end and the other end generally defines the equipment connection end. In one type of fluid coupling, a stem is provided having a first end, the equipment connection end, and a second end, the hose connection end, wherein the second end includes a shell placed over the stem. The first end of the stem may be threaded or may include a nut placed thereon for engaging the equipment. The external surface of the second end of the stem typically engages the internal surface of a hose, while the internal surface of the shell engages the external surface of the hose. 
         [0003]    During the manufacture of such fluid couplings, a wrenching surface, such as a hexagonal surface, is generally provided on the outer portion of the shell. A wrench, or other suitable tool, may be used to engage the wrenching surface while securing the equipment connection end of the fluid coupling to the equipment. This maintains stability of the hose connection end and prevents damage to the hose and/or its connection to the coupling by a resulting tendency to twist during the securing procedure. The hexagonal surface is generally provided at a different horizontal location of the fluid coupling than the horizontal location of a joined portion of the stem and the shell. Common methods of joining the coupling pieces include crimping, staking, swaging, etc. 
         [0004]    U.S. Pat. No. 5,419,028 teaches a method of making a hose coupling. Specifically, a method of forming a ferrule of the hose coupling is taught. The ferrule is then joined to an insert of the hose coupling using well-known methods. These methods include inwardly deforming or crimping the ferrule toward the insert at a horizontal location of the hose coupling different than the horizontal location of an enlarged hex-shaped nut portion. Inherently, separate steps are required to form the hex-shaped nut portion and the joined portion. In addition, because each of the hex portion and the joined portion occupies a separate horizontal space, the ferrule of this method may require additional raw material to construct the coupling. It is therefore desirable to provide a more efficient method of making a hose coupling. 
         [0005]    The present disclosure is directed to one or more of the problems set forth above. 
       SUMMARY OF THE INVENTION 
       [0006]    In one aspect, a method of making a fluid coupling includes a step of providing a cylindrical stem having a fluid conduit therethrough. A hollow shell is placed over a first end of the stem. The shell is die swaged to the stem at an attachment location along a length of the stem. The die swaging step includes forming a tool engaging hexagonal shape on an outer surface of the shell at the attachment location. 
         [0007]    In another aspect, a fluid coupling includes a cylindrical stem having a fluid conduit therethrough, and a hollow shell provided over a first end of the stem. The fluid coupling also includes a tool engaging hexagonal shape on an outer surface of the shell at an attachment location of the shell to the stem. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a side diagrammatic view of a fluid hose having a fluid coupling secured to each end; 
           [0009]      FIG. 2  is a cross-sectional view along line  2 - 2  of  FIG. 1 ; 
           [0010]      FIG. 3  is a cross-sectional view of another embodiment of a fluid coupling according to the present disclosure; 
           [0011]      FIG. 4  is a cross-sectional view of yet another embodiment of a fluid coupling according to the present disclosure; 
           [0012]      FIG. 5  is a cross-sectional view of yet another embodiment of a fluid coupling according to the present disclosure; 
           [0013]      FIG. 6  is a top diagrammatic view of a die set for making a fluid coupling according to the present disclosure; and 
           [0014]      FIG. 7  is a top diagrammatic view of the tool engaging hexagonal surface of a fluid coupling according to the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring to  FIG. 1 , a hose assembly  10  includes a fluid hose  12  and fluid couplings  14  and  16 . Generally, each of the fluid couplings  14  and  16  includes stems  18  and  20 , respectively, and shells  22  and  24 , respectively. Each of the shells  22  and  24  is configured to engage the fluid hose  12 . A nut may be provided at the end of the coupling opposite the shell for engaging an equipment connection. For example, fluid coupling  14  includes a nut  26  and fluid coupling  16  includes a nut  28 . A tool engaging hexagonal surface, such as surfaces  30  and  32 , may be provided on the fluid couplings  14  and  16  for engagement by a tool, such as, for example, a wrench. 
         [0016]      FIG. 2  shows a cross-sectional view along lines  2 - 2  of the fluid coupling  14  of  FIG. 1 . Fluid coupling  14  may be, for example, a hydraulic coupling, and may be made of any suitable material, such as, for example, a metallic bar stock material. The stem  18  of the fluid coupling  14  has an equipment connection end, shown generally at  40 , and a hose connection end, shown generally at  42 . The equipment connection end  40  is configured to connect fluid coupling  14  to various types of industrial equipment and machinery via the connection ports or manifolds of the equipment. The nut  26  may be provided on the stem  18  for engaging equipment (not shown). Alternatively, the stem  18  may be threaded at the equipment connection end  40  for engaging the port or manifold of the equipment. 
         [0017]    The shell  22  is positioned around the stem  18  at the hose connection end  42 . A hose, such as, for example, the hose  12  of  FIG. 1 , may be secured to the fluid coupling  14  by positioning the hose between the stem  18  and the shell  22 . An inner surface of the shell  22  may be provided with at least one annular projection, such as, for example, projections  44 ,  46 , and  48 , for providing a secure engagement with the hose. In addition, an external surface of the stem  18  at the hose connection end  42  may include annular indentations and/or projections to assist with hose engagement. 
         [0018]    A wrenching surface, such as the tool engaging hexagonal surface  30 , is generally provided on the outer portion of the shell  22 . A wrench, or other suitable tool, may be used to engage the tool engaging hexagonal surface  30  while securing the equipment connection end  40  of the fluid coupling  14  to some equipment. This maintains stability of the hose connection end  42  and prevents twisting damage to the hose and/or its connection to the coupling  14  by a resulting rotation. The tool engaging hexagonal surface  30  is provided at the same horizontal location of the fluid coupling  14  as the horizontal location of a joined portion  50  of the stem  18  and the shell  22 . A step area  52  may also be provided on the external surface of the shell  22  to prevent the nut  26  from interfering with the formation of the tool engaging hexagonal surface  30  during a die swaging process, or any other suitable process. 
         [0019]    The fluid coupling of the present disclosure may be of any conventional configuration well known to the art, including, but not limited to, a male pipe coupling  60 , as shown in  FIG. 3 , a JIC 37 Degree Flare coupling  62 , as shown, for example, in  FIG. 4 , or an angled connection coupling  64 , as shown in  FIG. 5 . In these figures, it should be readily apparent that, for the sake of clarity, only those parts which are relevant to a discussion of the tool engaging hexagonal surface  30  and the joined portion  50  are numbered. 
         [0020]      FIG. 6  shows a die set  70  that may be used to join the shell  22  to the stem  18  of the fluid coupling  14 . The die set  70 , shown in a closed position, includes six die segments  72 - 82 . Each die segment  72 - 82  includes a generally planar internal surface, shown at  84 - 94 , respectively. A well-known machine, as will be appreciated by those skilled in the art, engages segments  72 - 82  using bolts  96 - 106 . The die set  70  is configured to close radially inward around the shell  22  and stem  18  to form tool engaging hexagonal surface  30  and also mechanically join the shell to the stem through deformation of the shell. The tool engaging hexagonal surface  30 , therefore, is located at the same horizontal position along the fluid coupling  14  as the position at which the shell  22  and stem  18  are joined, namely, joined portion  50 . Although six die segments are shown, one skilled in the art will appreciate that two or more die segments may be used, as long as the inner surfaces of the die segments form a hexagonal shape when in a closed position. 
       INDUSTRIAL APPLICABILITY 
       [0021]    According to  FIGS. 1-7 , a fluid coupling, such as, for example, fluid coupling  14 , generally comprises a stem  18  having an equipment connection end, shown generally at  40 , and a hose connection end, shown generally at  42 . The equipment connection end  40  may include a nut  26  thereon for engaging equipment, and the hose connection end  42  may include a shell  22  positioned around the stem  18 . A hose may be secured to the fluid coupling  14  by positioning the hose between the stem  18  and the shell  22 . A wrenching surface, such as a tool engaging hexagonal surface  30 , is generally provided on the outer portion of the shell  22 . A wrench, or other suitable tool, may be used to engage the tool engaging hexagonal surface  30  while securing the equipment connection end  40  of the fluid coupling  14  to the equipment to avoid twisting. This maintains stability of the hose connection end  42  and prevents damage to the hose by a resulting rotation of the shell  22 . 
         [0022]    During manufacture, the shell  22  is typically joined to the stem  18  using well-known methods such as crimping, staking, swaging, etc. The joined portion or area is typically at a horizontal location of the hydraulic coupling  14  different than that of the tool engaging hexagonal surface  30  because separate steps are undertaken to form the hexagonal surface and join the shell  22  to the stem  18 . 
         [0023]    The method of making a fluid coupling according to the present disclosure is advantageous because it provides a more cost efficient method of making the coupling. Both the stem  18  and the shell  22  are machined to a predetermined size and shape out of a metal, such as, for example, a bar of round metal stock. The shell  22 , after machined, includes a first end having an outer diameter greater than an outer diameter of a second end. The second end may also include a step area  52  to assist in the die swaging process. The shell  22  is then die swaged to the stem  18 , using the die segments  72 - 82 , at the second end of the shell. The step area  52  prevents the nut  26  from interfering with the formation of the tool engaging hexagonal surface  30  in the event that the nut migrates into contact with the shell  22  during the swaging process. The tool engaging hexagonal surface  30  is provided at the same horizontal location of the fluid coupling  14  as the horizontal location of the joined portion  50  of the stem  18  and the shell  22 . This allows for a shell component that is shorter in length than prior art couplings. A shorter shell permits a shorter stem. 
         [0024]    The inner diameter and outer diameter of the second end of the shell  22  should be sized so that a proper hexagonal shape is formed after the shell and the stem  18  are die swaged using the die segments  72 - 82 . A proper hexagonal shape, for example, the tool engaging hexagonal surface  30  as shown in  FIG. 7 , may comprise a hexagonal shape where a peak to peak measurement  110  is about 1.1 times a flat to flat measurement  112 . Rounded portions  114 - 124  connect flats  126 - 136  of the tool engaging hexagonal surface  30  and may reflect undeformed surfaces. It is also important that a secure connection is formed between the stem  18  and the shell  22  at the joined portion  50 . 
         [0025]    To determine the inner and outer diameters of the shell  22 , it may be useful to assume that the area of the shell is about the same before the swaging process (“pre-swaged”) and after the swaging process (“post-swaged”). Specifically, it may be assumed that the pre-swaged area is the difference between the area of a pre-swaged outer diameter  138  (A OD ) and the area of a pre-swaged inner diameter  140  (A ID-1 ). It may also be assumed that the post-swaged area is the difference between the area of a post-swaged hexagonal surface  142  (A HEX ) and the area of a post-swaged inner diameter  144  (A ID-2 ). The equation is as follows: 
         [0000]      ( A   OD )−( A   ID-1 )=( A   HEX )−( A   ID-2 ) 
         [0026]    By using inner diameter calculations from a previous swaging or joining process and a value for a desirable hexagonal surface, an approximate pre-swaged outer diameter can be determined for the shell  22 . Those skilled in the art will recognize that this suggestion reflects a starting point. Further tests and iterations about this starting point may be needed to arrive at a suitable result for each specific application. Suitable, in this context, means a good shell to stem connection and an adequate tool engagement surface. 
         [0027]    As an example, a previous joining process may utilize a shell having a pre-swaged inner diameter of 0.440 inches and a post-swaged inner diameter of 0.390 inches. These diameters can be used to derive at areas, for example, 0.152 inches 2  and 0.119 inches 2 , respectively. If the area of a desirable post-swaged hexagonal surface is 0.410 inches 2 , the equation now includes the following values: 
         [0000]      ( A   OD )−0.152 inches 2 =0.410 inches 2 −0.119 inches 2    
         [0028]    We can easily conclude that the pre-swaged diameter is 0.751 in. From there, and using a stem sized for use with a previous joining process, the inner and outer diameters of the shell  22  may be adjusted to attain values providing a proper post-swaged hexagonal surface and a secure connection to the stem  18 . 
         [0029]    The fluid coupling  14  may be manufactured for use with a fluid hose, such as, for example, fluid hose  12 , having an internal surface diameter of about ¼ inch, ⅜ inch, ½ inch, or any other useful diameter. Specifically, the fluid hose may meet Society of Automotive Engineer (SAE) standard J517 and may be compatible with series 100R1, 100R2, 100R3, 100R6, 100R7, 100R12, 100R14, 100R15, 100R16, or 100R17, of that standard. Alternatively, the fluid hose may meet Deutsches Institut fur Normung (DIN) standard 20023. These standards are provided as examples only, and one skilled in the art will appreciate that the present method may be useful in manufacturing a variety of fluid couplings. 
         [0030]    The fluid coupling  14  manufactured according to the method of the present disclosure may provide savings of over 10% of manufacturing costs by joining the shell  22  to the stem  18  in the same step that forms the tool engaging hexagonal surface  30 . In addition, because each of the tool engaging hexagonal surface  30  and the joined portion  50  occupies the same horizontal space along the coupling  14 , the shell  22  and/or stem  18  of this method may be able to have shortened lengths. This would also provide cost savings in that less material is required to produce the fluid coupling  14 . 
         [0031]    It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present invention in any way. Thus, those skilled in the art will appreciate that other aspects of the invention can be obtained from a study of the drawings, the disclosure and the appended claims.