Abstract:
A plumbing connector and method of connection including: a fitting having external threads on at least the first end; a tube having a first end inserted into the first end of the fitting; and an annular gasket, a compression ring, a lock ring, and a nut coaxial with and surrounding the outer diameter of the tube. The nut has internal threads adapted to engage the external threads of the fitting and is adapted to contain the gasket, the compression ring, and the lock ring upon threading of the nut onto the fitting. Upon threading and tightening of the nut onto the fitting, the gasket is compressed, an inner edge of the lock ring bitingly engages the outer diameter of the tube, and the gasket forms a seal with at least the first end of the fitting, the outer diameter of the tube, and an outer edge of the lock ring.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 61/975,400, filed Apr. 4, 2014, which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a plumbing connector utilizing a fitting securement ring within a threaded connector. More specifically, the invention is directed to a plumbing connector for attaching a vacuum breaker tube to the outlet of a flush valve. 
         [0004]    2. Description of Related Art 
         [0005]    In a typical flush valve assembly, a vacuum breaker tube is attached to the outlet of the flush valve. This vacuum breaker tube is attached with additional fittings leading up to a fixture or directly to the spud of a fixture. There have been many problems with blow-outs of the vacuum breaker tube when it is not sufficiently secured to the fixture. Because a flush valve is used to flush water at high velocities, the joint where the tube and the fixture are connected can become compromised causing the tube to blow out of the fitting. These blow-outs can lead to flooding of the surrounding area. 
         [0006]    An example of a prior art connector  10  is shown in  FIG. 1 . The assembly consists of the vacuum breaker tube  12  and a fitting  14 , in this case, a brass elbow. The elbow fitting  14  includes a brass body, a brass nut  16 , a friction ring  18 , and a rubber gasket  20 . The brass nut  16  is slipped over the tube  12  followed by the friction ring  18 , and then the rubber gasket  20 . Once these items are slipped over the tube  12 , the tube  12  can then be inserted into the elbow fitting  14 . The internal threads of the nut  16  are then threaded onto the external threads of the elbow fitting  14 . As the nut  16  is threaded to the elbow, the assembly gets tighter and the gasket  20  begins to compress between the top of the nut  16  and the top of the fitting  14  as shown in  FIG. 2 . As the gasket  20  is compressed, its inner walls tightly engage the tube&#39;s  12  outer wall. At the same time, the bottom of the gasket  20  is being compressed into the end of the elbow fitting  14 . In this manner, two seals are created. One seal is created by the compression of the gasket  20  against the tube&#39;s  12  outer wall. The second seal is created by the compression of the bottom of the gasket  20  against the elbow fitting&#39;s  14  flat top edge. The grip of the rubber gasket  20  on the tube  12  is the only part preventing the tube  12  from blowing out of the elbow fitting  14 . This type of securement often proves to be insufficient to overcome the force created by the flushing of the flush valve and the vacuum tube  12  is blown out the fitting  14 . 
       SUMMARY OF THE INVENTION 
       [0007]    In one aspect, the present invention is directed to a plumbing connector including: a fitting having a first end and a second end and having external threads on at least the first end; a tube having a first end and a second end, the first end of the tube inserted into the first end of the fitting; and an annular gasket, a compression ring, a lock ring, and a nut coaxial with and surrounding the outer diameter of the tube. The nut has internal threads adapted to engage the external threads of the fitting and is adapted to contain the gasket, the compression ring, and the lock ring upon threading of the nut onto the fitting via the internal threads of the nut and the external threads of the fitting. Upon threading of the nut onto the fitting via the internal threads of the nut and the external threads of the fitting and tightening of the nut, the gasket is compressed, an inner edge of the lock ring bitingly engages the outer diameter of the tube, and the gasket forms a seal with at least the first end of the fitting, the outer diameter of the tube, and an outer edge of the lock ring. As the nut is advanced onto the fitting, the gasket first contacts the compression ring before contacting the lock ring and the inner and outer edges of the compression ring contact the lock ring. Upon tightening of the nut, contact between the compression ring and the lock ring deforms the lock ring pushing the inner edge of the lock ring into a biting engagement with the outer diameter of the tube and the outer edge of the lock ring into a sealing engagement with the gasket. 
         [0008]    The compression ring may have an outer diameter smaller than an outer diameter of the lock ring and may comprise a concave side and a convex side where the convex side of the compression ring is adjacent the gasket and the concave side of the compression ring is adjacent the lock ring. 
         [0009]    The inner edge of the lock ring may have a series of teeth and the lock ring may comprise a concave side and a convex side where the concave side of the lock ring is adjacent the compression ring and the convex side of the lock ring is adjacent an upper ledge of the nut. 
         [0010]    The plumbing connector may also include a friction ring, which may have an outer diameter smaller than an outer diameter of the lock ring, placed between the gasket and the compression ring. 
         [0011]    In a further aspect, the present invention is directed to a method of connecting a plumbing fitting to a tube. A fitting having a first end and a second end and having external threads on at least the first end and a tube having a first end and a second end are provided. In the following order: a nut having internal threads adapted to engage the external threads of the fitting, a lock ring having an inner edge and an outer edge, a compression ring having an inner edge and an outer edge, and an annular gasket are slid onto the first end of the tube. The nut is adapted to contain the gasket, the compression ring, and the lock ring upon threading of the nut onto the fitting via the internal threads of the nut and the external threads of the fitting. The first end of the tube is placed into the inner diameter of the first end of the fitting and the nut is threaded onto the fitting and tightened. After tightening of the nut is completed, the gasket is compressed, the inner edge of the lock ring bitingly engages the outer diameter of the tube, and the gasket forms a seal with at least the first end of the fitting, the outer diameter of the tube, and the outer edge of the lock ring. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a plumbing connector according to the prior art prior to making the connection; 
           [0013]      FIG. 2  is a cross-section of the prior art plumbing connector of  FIG. 1  after the connection has been made; 
           [0014]      FIG. 3  is a perspective view of a plumbing connector prior to making the connection according to one aspect of the present invention; 
           [0015]      FIG. 4  is a cross-section of the plumbing connector of  FIG. 3  after threading the nut onto the fitting but before tightening the nut; 
           [0016]      FIG. 5  is a perspective view of a compression ring and a lock ring according to one aspect of the present invention; 
           [0017]      FIG. 6  is a cross-section of the plumbing connector of  FIG. 3  after tightening the nut; 
           [0018]      FIG. 7  is a perspective view of a lock ring according to a second aspect of the present invention; 
           [0019]      FIG. 8  is a cross-section of a plumbing connector after threading the nut onto the fitting but before tightening the nut according to a second aspect of the present invention; and 
           [0020]      FIG. 9  is a cross-section of the plumbing connector of  FIG. 8  after tightening the nut. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    For purposes of the description hereinafter, the terms “end”, “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal”, and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary aspects of the invention. Hence, specific dimensions and other physical characteristics related to the aspects disclosed herein are not to be considered as limiting. Further, it is to be understood that the invention may assume various alternative variations except where expressly specified to the contrary. 
         [0022]    As shown in  FIG. 3 , the plumbing connector  22  comprises a fitting  24  having a first end  26  and a second end  28  and having external threads  30  on at least the first end  26 . The fitting  24  may be any suitable fitting for attaching a tube to a flush valve including, but not limited to, an elbow (as shown in  FIG. 1 ), a tee, or a fitting that is integral with a flush valve. 
         [0023]    The plumbing connector  22  also includes a tube  32  having a first end  34  and a second end  36 . At least the first end  34  of the tube  32  has an outer diameter that is smaller than the inner diameter of the first end  26  of the fitting  24  such that the first end  34  of the tube  32  can be inserted into the first end  26  of the fitting  24 . Preferably, the outer diameter of the tube  32  is only slightly smaller than the inner diameter of the fitting  24  to provide a tight fit between the two. 
         [0024]    The fitting  24  and the tube  32  may be made of any suitable material including, but not limited to, brass, plastic, chrome, and steel. 
         [0025]    The plumbing connector  22  includes an annular gasket  38 . The gasket  38  has an inner diameter equal to or slightly larger than the outer diameter of the tube  32  and an outer diameter equal to or slightly smaller than the inner diameter of the first end  26  of the fitting  24 . The gasket  38  may be made from any suitable compressible material including, but not limited to, rubber. The gasket  38  is used to help hold the tube  32  within the fitting  24  via compressive and frictional forces between the gasket  38  and the tube  32 . The gasket  38  is also part of the sealing system of the connector  22 . 
         [0026]    The connector  22  includes a compression ring  40  having an outer edge  42  and an inner edge  44 , and a lock ring  46  having an outer edge  48  and an inner edge  50 . The compression ring  40  and the lock ring  46  are made of a deformable material, preferably stainless steel. The material of the lock ring  46  may have a hardness greater than the hardness of the tube  32 . 
         [0027]    The connector  22  includes a nut  52  having internal threads  54  adapted to engage the external threads  30  of the fitting  24 . 
         [0028]      FIG. 4  shows the connector in the partially assembled condition where the internal threads  54  of the nut  52  have been threaded onto the external threads  30  of the fitting  24 , but the threaded arrangement has not yet been tightened. As shown in  FIG. 4 , the nut  52  has an upper ledge  56  and a cavity  58  adapted to contain the gasket  38 , the compression ring  40 , and the lock ring  46  upon threading of the nut  52  onto the fitting  24  via the internal threads  54  of the nut  52  and the external threads  30  of the fitting  24 . 
         [0029]    As can be seen from  FIGS. 4 and 5 , which show the compression ring  40  and the lock ring  46  in more detail, the compression ring  40  is generally cup-shaped having a curved cross-section and comprising a concave side  60  and a convex side  62 . The curve of the compression ring  40  is such that the inner edge  44  is on a different horizontal plane than the outer edge  42  as shown in  FIG. 5 . 
         [0030]    The lock ring  46  is also generally cup-shaped having a curved cross-section and comprising a concave side  64  and a convex side  66 . 
         [0031]    The compression ring  40  has an outer diameter that is smaller than the outer diameter of the lock ring  46 . 
         [0032]    To assemble the connector  22 , the nut  52  is first slid over the tube  32  followed by the lock ring  46 . The lock ring  46  is placed over the tube  32  such that the convex side  66  of the lock ring  46  faces the upper ledge  56  of the nut  52  and the concave side  64  of the lock ring  46  faces the first end  34  of the tube  32 . Due to the curved cross-section of the lock ring  46 , the inner edge  50  of the lock ring  46  is pointing away from the ledge  56  of the nut  52 . The compression ring  40  is then placed over the tube  32  such that the concave side  60  of the compression ring  40  faces the lock ring  46  and the convex side  62  of the compression ring  40  faces the first end  34  of the tube  32 . The gasket  38  is then placed over the tube  32  and the first end  34  of the tube  32  is inserted into the fitting  24 . 
         [0033]    The nut  52  is then advanced onto the fitting  24  via the internal threads  54  of the nut  52  and the external threads  30  of the fitting  24 . As can be seen in  FIG. 4 , when the nut  52  has been screwed onto the fitting  24  but has not yet been tightened, the compression ring  40  extends into the concave side  64  of the lock ring  46 , and the inner edge  44  and the outer edge  42  of the compression ring  40  contact the concave side  64  of the lock ring  46 . The convex side  66  of the lock ring  46  contacts the ledge  56  of the nut  52  and the outer edge  48  of the lock ring  46  is not in contact with either the compression ring  40  or the gasket  38 . One end of the gasket  38  contacts the first end  26  of the fitting  24  and the other end of the gasket  38  contacts the convex side  62  of the compression ring  40 . 
         [0034]    When the nut  52  is then tightened onto the fitting  24  via the internal threads  54  of the nut  52  and the external threads  30  of the fitting  24  as shown in  FIG. 6 , several things occur. The gasket  38  compresses. As the assembly gets tighter, the compression ring  40  and the lock ring  46  begin to deform from the compressive forces placed on them by the ledge  56  of the nut  52  and the gasket  38 . The edges  42 ,  44  of the compression ring  40  force the inner edge  50  of the lock ring  46  upward toward the ledge  56  of the nut  52  and force the outer edge  48  of the lock ring  46  into a biting engagement with the outer wall of the tube  32 . The outer edge  48  of the lock ring  46  after deformation is angled at a precise angle to achieve optimal holding strength. As the inner edge  50  of the lock ring  46  deforms and locks into the outer wall of the tube  32 , the outer edge  48  of the lock ring  46  is deformed in a downward and inward direction pushing on the gasket  38 . This ensures the gasket  38  does not leak due to the added deformation of its shape and adds to the stability of the water tight seal. 
         [0035]    The compression ring  40  also deforms such that its inner edge  44  and outer edge  42  become closer to being on the same horizontal plane. Both the inner edge  44  and outer edge  42  of the compression ring  40  contact the concave side  64  of the lock ring  46  and the convex side  62  of the compression ring  40  contacts the gasket  38  forming a seal between the compression ring  40  and the gasket  38 . 
         [0036]    Upon the flushing action of the valve, the water pressure will try to pull the tube  32  out of the fitting  24  but, with the lock ring  46 /compression ring  40  assembly in place as the tube  32  tries to pull away from the fitting  24 , the inner edge  50  of the lock ring  46  will only dig further in the tube  32 . 
         [0037]    In another aspect of the invention, the inner edge  50  of the lock ring  46  may comprise a series of teeth  67  as shown in  FIG. 7 . 
         [0038]    As shown in  FIGS. 8 and 9 , the connector  22  may further comprise a friction ring  68  placed between the compression ring  40  and the gasket  38 . The friction ring&#39;s  68  outer diameter is sized so that it does not interfere with the seal between the outer edge  48  of the lock ring  46  and the gasket  38  when the connector  22  is tightened. In one aspect of the invention shown in  FIGS. 8 and 9 , the outer diameter of the friction ring  68  is smaller than the outer diameter of the lock ring  46 . The friction ring  68  may provide additional support for deformation of the compression ring  40  and the lock ring  46  on tightening of the connector  22  and may be used to assure that the lock ring  46  does not cut into the soft gasket  38 . The friction ring  68  may be made from materials including, but not limited to, brass and rubber. 
         [0039]    A connector according to the prior art was made using a chrome vacuum tube, a brass elbow fitting, a rubber gasket and friction ring, and a brass nut. The pullout force necessary to remove the tube was determined using a 50 lb. force gauge after tightening the connector using a slip nut wrench and applying various levels of torque. At each torque level, three tests were made. A compression ring and lock ring having teeth according to the invention were made of 3D printed photopolymer material and included in the connector and the testing was repeated. The results are shown in Table 1 below. The force necessary to remove the tube from the fitting was increased by up to 20% by the addition of the compression ring and lock ring. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
             
               
             
               
               
               
               
             
               
             
               
               
               
               
             
               
             
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                   
                 Pullout Force (lbs.) 
               
             
          
           
               
                   
                   
                 Without compression  
                 With compression  
               
               
                   
                   
                 ring and lock ring 
                 ring and lock ring 
               
               
                   
                   
               
             
          
           
               
                  90 in.-lbs. torque 
               
             
          
           
               
                   
                 Trial #1 
                 33 
                 44 
               
               
                   
                 Trial #2 
                 35 
                 39 
               
               
                   
                 Trial #3 
                 34 
                 40 
               
               
                   
                 Average 
                 34 
                 41 
               
             
          
           
               
                 135 in.-lbs. torque 
               
             
          
           
               
                   
                 Trial #1 
                 40 
                 45 
               
               
                   
                 Trial #2 
                 42 
                 50 
               
               
                   
                 Trial #3 
                 41 
                 &gt;50 
               
               
                   
                 Average 
                 41 
                 49 
               
             
          
           
               
                 180 in.-lbs. torque 
               
             
          
           
               
                   
                 Trial #1 
                 47 
                 &gt;50 
               
               
                   
                 Trial #2 
                 48 
                 &gt;50 
               
               
                   
                 Trial #3 
                 46 
                 &gt;50 
               
               
                   
                 Average 
                 47 
                 &gt;50 
               
               
                   
                   
               
             
          
         
       
     
         [0040]    Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred aspects of the present invention, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed aspects, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of this specification. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any aspect of the invention can be combined with one or more features of any other aspect of the invention.