Abstract:
An expansion jaw assembly for use in expanding an end fitting within a fluid hose comprises a plurality of elongated jaw elements configured when combined to form a cylindrical body sized for introduction into the interior of the end fitting. The jaw elements when combined define a tapered bore for receiving an expansion pin to move the jaw elements radially apart relative to each other, to thereby expand the diameter of the combined jaw elements within the end fitting. Each jaw element includes a plurality of rib segments projecting from an outer surface of the jaw element, the rib segments spaced along the length of the jaw element. The rib segments are defined by a radially outermost plateau, a fillet radius from the plateau to the outer surface of the jaw element.

Description:
REFERENCE TO RELATED APPLICATION AND PRIORITY CLAIM 
       [0001]    This application is a utility filing of and claims priority to provisional application No. 61/816,603, filed on Apr. 26, 2013, the disclosure of which is incorporated herein in its entirety. 
     
    
     BACKGROUND 
       [0002]    Typical hose couplings are shown in  FIGS. 1   a ,- 1   c . As illustrated, a ferrule  10  is slipped over the end of the hose H and the shank  14  of the male ( FIG. 1   a ) or the shank of the female ( FIG. 1   b ) hose fitting  18  is inserted through the ferrule hole  11 , into the inner diameter of the hose up to the formed shoulder  15 . The male assembly of  FIG. 1   a  terminates in an externally threaded end  12 , while the female assembly of  FIG. 1   b  terminates in a female end  13  that is curled upward  13 ′ to engage a coupling nut  16 , as shown in  FIG. 1   c.    
         [0003]    With the ferrule  10  positioned on the outside of the hose H and the shank  14  on the inside of the hose, a sectioned jaw tool  20 , shown in  FIG. 2   a , is inserted into the shank. A tapered pin  22  is then inserted into the inner diameter of the jaws to expand the jaw elements  21  radially outward, thereby expanding the shank outward into the hose. The jaw elements are pivotably held together at one end by O-rings. The jaw elements  22  include expansion profiles or ridges  25 ,  26  that complement the ribs  10   a  ( FIGS. 1   b ,  1   c ) stamped into the ferrule. Thus, the expansion of the jaw tool  20  forms grooves  27  in the shank  14  and compresses the hose into the grooves  10   a  of the ferrule  10 , as shown in  FIGS. 3-4 . 
         [0004]    The degree to which the shank must be expanded is determined by the thickness and the composition of the hose wall. With thinner, denser hose walls, the shank does not have to be expanded to as great an extent as a thick soft walled hose, as illustrated in  FIG. 3 . On the other hand, less dense, thicker hose walls require greater expansion of the shank, as depicted in  FIG. 4 . The amount of expansion can be expressed in terms of the height of the grooves  27  formed in the shank. For the more dense hose material the expansion can be denoted as X % of the shank diameter, while the less dense material expands Y % of the shank diameter, where X is greater than Y. 
         [0005]    The hose industry has used brass as a coupling material for many years. Brass coil stock is ductile enough to be easily formed with progressive dies and rolling tools for beading and threading. Once these forms are made they are still ductile enough for assembly. With the use of brass, the expansion required for X % or Y % diameter increase has been achievable. However, problems occur when less ductile materials are used and the problems are particularly more pronounced when a less dense, thicker walled hose is used. Another aspect of brass ferrules is that the ferrule  10  itself can expand when the shank  14  is expanded due to the ductility of the brass. For ferrules formed of less ductile material the expansion is very minimal, if at all. 
         [0006]    In spite of these disadvantages, the use of less ductile materials offers various benefits over the more ductile materials (brass) that are presently used in hose couplings. For instance, less ductile materials are stronger and more crush resistant that the ductile materials. In most cases the less ductile material is less expensive. 
       SUMMARY OF THE DISCLOSURE 
       [0007]    A method for engaging an end fitting to a fluid hose that includes mounting a compression ring around one end of the fluid hose and inserting the shank of the hollow end fitting into the interior of the fluid hose in radial alignment with the compression ring. In one aspect, the shank and the compression ring are formed of a low-ductility radially expandable material, such as a stainless steel. A conventional expansion tool or pin is inserted into the interior of the end fitting with the expansion surface of the expansion tool radially aligned with the compression ring. The compression ring is engaged with a conventional external circumferential compression tool. In accordance with the present disclosure, the method includes simultaneously expanding the expansion tool within the end fitting to expand the shank of the end fitting into the fluid hose, and actuating the compression tool to compress the compression ring into the fluid hose. 
         [0008]    In a further aspect, an expansion jaw assembly for use in expanding an end fitting within a fluid hose comprises a plurality of elongated jaw elements configured when combined to form a cylindrical body sized for introduction into the interior of the end fitting. The jaw elements when combined define a tapered bore for receiving an expansion pin to move the jaw elements radially apart relative to each other, to thereby expand the diameter of the combined jaw elements within the end fitting. Each jaw element includes a plurality of rib segments projecting from an outer surface of the jaw element, the rib segments spaced along the length of the jaw element. The rib segments are defined by a radially outermost plateau, a fillet radius from the plateau to the outer surface of the jaw element. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0009]      FIGS. 1   a ,  1   b ,  1   c  are side cross-sectional views of conventional hose coupling components of the prior art. 
           [0010]      FIGS. 2   a ,  2   b ,  2   c  are views of an expansion jaw assembly of the prior art used to engage hose coupling components, such as the components in  FIGS. 1   a - c , to a hose, including a perspective view of the tool and enlarged detail views of the profile of jaws of the assembly. 
           [0011]      FIG. 3  is a side cross-sectional view of the crimped engagement of the hose coupling components shown in  FIG. 1   a  to a dense, thin-walled hose. 
           [0012]      FIG. 4  is a side cross-sectional view of the crimped engagement of the hose coupling components shown in  FIG. 1   a  to a less dense, thick-walled hose. 
           [0013]      FIG. 5  is a side view of the coupling components according to one aspect of the present disclosure. 
           [0014]      FIG. 6  is a side cross-sectional view of the coupling components shown in  FIG. 5  engaged to a hose. 
           [0015]      FIG. 7  is a side cross-sectional view of the coupling components shown in  FIG. 5  engaged to a hose showing the amount of compression and expansion applied to the components. 
           [0016]      FIG. 8  is an enlarged view of the shank of a coupling component exhibiting stress fractures under expansion forces. 
           [0017]      FIG. 9  is an enlarged view of the shank of a coupling component exhibiting stress fractures under expansion forces 
           [0018]      FIG. 10  is a perspective view of an expansion jaw assembly according to one aspect of the present disclosure. 
           [0019]      FIG. 11  is a side view of the expansion jaw assembly shown in  FIG. 10 . 
           [0020]      FIG. 12  is a cross-sectional view of the expansion jaw assembly shown in  FIG. 10 . 
           [0021]      FIG. 13  is an end view of the expansion jaw assembly shown in  FIG. 10   
           [0022]      FIG. 14  is an enlarged detail view of the rib segments for the jaw elements of the expansion jaw assembly shown in  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the invention is thereby intended. It is further understood that the present invention includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the invention as would normally occur to one skilled in the art to which this invention pertains. 
         [0024]    The present disclosure contemplates forming the hose coupling components of a less ductile material, such as stainless steel or plated/coated steel, or other materials of similar ductility. When the standard shaped expanding jaws (jaw assembly  20  of  FIG. 2   a ) and the normal insertion speed of the tapered pin (pin  22 ) into the jaws are used, a shank formed of a less ductile material is prone to cracking or splitting in two different directions. This problem is even more pronounced with the thicker, less dense walled hose. 
         [0025]    With the standard practice, the shank  14  is the part experiencing the greatest amount of expansion since the expanding jaws apply force only to the inside of the shank. To reduce the amount of expansion of the shank, the present disclosure contemplates applying force to the components in two directions at the same time, namely radially outward and radially inward. In some applications the shank may be a ridged structure with ridges on the outside of the shank. For instance, as shown in  FIGS. 5-6  a less ductile metal (i.e., steel) compression ring  40  is placed on hose H. A metal shank  51  of the coupling or fitting  50  is inserted into inner diameter of the hose. The shank  51  may include ridges  52  to enhance engagement with the hose. In one aspect, the compression ring  40  is deformed inward by a force Fi at a middle portion  41  of the ring, as illustrated in  FIGS. 6-7 , to compress the hose H against the ridges  52 . The compressive or crimping force Fi may be applied using a conventional crimping ring tool that provides a compressive force around the entire circumference. At the same time, the expanding jaw assembly  20  may be used at the inner diameter of the shank  51  to apply a radially outward force Fo. This allows the inner and outer components (the ring  40  and the shank  51 ) to be deformed about half as much as if the expansion force were applied to a single part. Limiting the deformation of the less ductile material reduces the risk that the components will crack or split. Thus, for a thin-walled hose of  FIG. 6 , the expansion of X % (see  FIG. 3 ) can be half (X/2%) for both the ring and the shank. Similarly, for the thick-walled hose of  FIG. 7  the expansion can be also be half (Y/2%) for the two components. 
         [0026]    Thus, the present disclosure contemplates a method for engaging an end fitting to a fluid hose that includes mounting a compression ring around one end of the fluid hose and inserting the shank of the hollow end fitting into the interior of the fluid hose in radial alignment with the compression ring. In one aspect, the shank and the compression ring are formed of a low-ductility radially expandable material, such as a stainless steel. A conventional expansion tool or pin is inserted into the interior of the end fitting with the expansion surface of the expansion tool radially aligned with the compression ring. The compression ring is engaged with a conventional external circumferential compression tool. In accordance with the present disclosure, the method includes simultaneously expanding the expansion tool within the end fitting to expand the shank of the end fitting into the fluid hose, and actuating the compression tool to compress the compression ring into the fluid hose 
         [0027]    Typical jaws have expansion profiles  25 ,  26  that have relatively sharp corners, as illustrated in  FIGS. 2   b ,  2   c . The sharp corners on the conventional expanding jaws cause stress cracks as illustrated in  FIGS. 8 and 9 . Thus, cracks can form and propagate in a direction C perpendicular to the insertion direction I of the expanding jaws ( FIG. 8 ) and parallel to the insertion direction ( FIG. 9 ) as the jaws are expanded. As the jaws are expanded radially outward, the less ductile material cannot expand quickly enough, leading to the formation of cracks. For a plated or coated material, if the expansion is too rapid the coating can separate or flake away, which exposes the coupling component to corrosion. 
         [0028]    In order to overcome this problem when using less ductile material for the hose coupling components, the present disclosure contemplates reducing the insertion speed of the pin  22  into the jaw assembly, such as assembly  20 , to more gradually expand the jaw assembly and ultimately to more gradually deform the shank of the fitting. In addition, the present disclosure contemplates modifying the expanding jaw assembly as shown in  FIGS. 10-14 . The expansion jaw assembly  60  of  FIG. 10  includes jaw elements  61  each having circumferential rib segments  62  formed along the length of their outer surface. The jaw elements are configured when combined to form a generally cylindrical body sized for insertion into the end fitting  50 . Moreover, when combined the circumferential rib segments  62  of the jaw elements form a generally continuous circumferential rib prior to expansion of the jaw assembly. 
         [0029]    In one aspect of the present disclosure, the rib segments are rounded to eliminate the sharp corners of the prior jaw designs. As shown in the detail view of  FIG. 14 , the rib segments  62  have a narrow plateau  63  flanked by rounded corners  64 . The rounded corners merge into the body of the jaw  61  at a radius  65  in the nature of a fillet radius. Thus, rather than presenting abrupt sharp corners and edges to the coupling components, as with the prior expansion profiles  25 ,  26 , the expansion profile of the rib segments  62  shown in  FIG. 14  provides a more gradual surface for contacting the less ductile material. In a specific embodiment, the plateau  63  has a width of about 0.028 in. and a radius  66  is about 0.059 in. The transition from the fillet radius  66  to the plateau  63  can have a radius of about 0.016 in. In the embodiment depicted in  FIGS. 10-13 , the expansion jaw assembly  60  includes seven jaw elements uniformly spaced around the circumference at 45° intervals. In the illustrated embodiment, the jaw elements  61  each include four ribs  62  that span the angular extent of the jaw. 
         [0030]    The jaw assembly  60  defines a tapered bore  67  therethrough adapted to engage an expansion tool, such as the tapered pin  22  shown in  FIG. 2   a . The tapered bore may be defined at an angle of 5 degrees. Each jaw element may include a circumferential groove  68  on the exterior of an enlarged head portion  69  of the jaw element  61  and a groove  70  on a shank portion  71  of the jaw element. The grooves  68 ,  70  are configured to receive an elastic O-ring to hold the separate jaw elements  61  together in a conventional manner. The O-rings also provide elastic resistance to expansion of the jaw assembly  60  during insertion of the pin  22 . 
         [0031]    The benefits of the modified expansion profiles are demonstrated by stress analysis of the shank  14  ( FIG. 1 ) or  51  ( FIG. 7 ) of a corresponding fitting  18 ,  50 . Stress analysis of an expansion force applied by an expansion jaw having a conventional profile, such as the profile  25  ( FIG. 2   b ), produces a maximum principal stress of 7.93 N/mm 2  at a maximum radial displacement of 3.562e −06  mm of the shank. On the other hand, the modified profile  62  shown in  FIG. 14   b  results in a comparable maximum principal stress of 8.622 N/mm 2  at a much greater maximum radial deformation of the shank as high as 9.32e −05  mm. Thus, the modified profile of the rib segments  62  permits about 25 times greater radial expansion than the conventional expansion rib profile. At a radial expansion comparable to the conventional rib design (i.e., at a radial deformation of 3.5e −06  mm) the stress experienced by the shank of the fitting is considerably less (in the range of about 2 N/mm 2 ) and well below the fatigue level of the less ductile material of the fitting shank  14 ,  51 . 
         [0032]    While the invention has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the invention are desired to be protected.