Abstract:
The present invention is directed towards a dust plug for insertion into a fluid conduit system. The dust plug is comprised of an insertion end, removal means, and a hollow central body located between the insertion end and the removal means. The insertion end of the plug is formed as a solid flat end so that when the plug is inserted into the fluid conduit system, the hollow interior of the plug does not communicate with the interior of the system. Additionally, the removal means is preferably formed as a continuous lip about the end of the hollow central body.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is directed towards a plug for a circular article. More particularly, the present invention is directed towards a dust plug for a fluid conduit system.  
         BACKGROUND OF THE INVENTION  
         [0002]    It is known in the fitting/coupling art to use dust plugs with fluid conduit systems, e.g. hoses, threaded pipes, that have been provided with a coupling. The dust plug is inserted into the end of the system, mating with the coupling, to prevent any loss of material from the system and to prevent the introduction of foreign material into the system. A conventional dust plug for a cam and groove fitting is illustrated in FIG. 5. The plug  100  has a central body  110  with a hollow center  112 . One end of the plug  114  has a tapered end  116  to facilitate insertion of the dust plug  100  into the hose. Along the length of the central body  110  is a groove  118  that cooperates with a lever arm of a cam and groove coupling. The other end of the dust plug  100  has a tab  120 . The tab  120  has an aperture  122  for inserting a chain. Typically, a chain is inserted into the tab  120  in order to mate the plug  100  with the system so that the plug  100  is not lost when not inserted into a coupling. However, since the tab  120  is the only portion of the plug  100  that is graspable once the plug  100  is inserted into a coupling, operators have tended to use the tab  120  as the removal means for the plug  100 , either by directly pulling on the tab  120  or pulling the chain threaded through the tab  120 .  
           [0003]    The dust plug  100  is inserted into a coupling so that the end  114  is inserted into the fluid conduit system while only the tab removal means  120  extends outside of the coupling and hose end. The hollow center  112  communicates with the interior of the system and any material that may flow through the system. To remove the dust plug  100  from the hose, after releasing the lever arm of the cam and groove fitting, the operator typically pulls any chain mounted through the aperture  122 .  
           [0004]    However, this dust plug  100  has several design limitations. Because the axial end  114  is a tapered ring of metal, the end  114  of the dust plug may become easily damaged by dropping the dust plug  100 . Since the hollow center  112  of the dust plug  100  communicates with the interior of the fluid conduit system and any material within the system, any dirt or any other foreign objects that enter into the hollow center  112  may enter the system and potentially contaminate the material flowing through the system. The shape of the dust plug  100  makes it difficult and time-consuming for an operator to clean out the hollow center  112  of the dust plug  100  each time the dust plug  100  is inserted into a coupling. Also, the configuration of the removal means  120  is susceptible to being damaged and broken off if the dust plug  100  is dropped or if the operator pulls too hard on any chain threaded through the aperture  122 . Once the removal means  120  is broken off, removal of the dust plug  100  becomes extremely difficult for the operator.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention is directed towards a dust plug for insertion into a fitting that overcomes or eliminates the disadvantages of the conventional dust plug. The dust plug is comprised of an insertion end, removal means, and a hollow central body located between the insertion end and the removal means. The plug is characterized by the insertion end being formed as a solid flat end.  
           [0006]    Another aspect of the inventive dust plug is that the removal means is formed as a continuous lip about the end of the hollow central body.  
           [0007]    In another aspect of the invention, the removal means has a diameter greater than the outer diameter of the hollow central body.  
           [0008]    In another aspect of the invention, the plug is further characterized by the plug comprising an intermediate area adjacent the removal means and the hollow central body. The intermediate area may have a diameter less than the outer diameter of the hollow central body. The intermediate area may also be provided with at least one tab formed therein so that a chain may be attached to the plug. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The invention will now be described by way of example and with reference to the accompanying drawings in which:  
         [0010]    [0010]FIG. 1 illustrates a dust plug in accordance with the present invention;  
         [0011]    [0011]FIG. 2 illustrates the dust plug along line  2 - 2  of FIG. 1;  
         [0012]    [0012]FIG. 3 illustrates the dust plug inserted into a cam and groove fitting crimped onto a hose end; and  
         [0013]    [0013]FIG. 4 illustrates the dust plug inserted into a cam and groove fitting for a threaded pipe assembly; and  
         [0014]    [0014]FIG. 5 illustrates a conventional prior art dust plug.  
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0015]    [0015]FIGS. 1 and 2 illustrate a dust plug  10  in accordance with the present invention. The illustrated dust plug  10  is for particular use with a cam and groove fitting but may be designed for used with any other type of conventional fitting where dust plugs are used to seal the end of an fluid conduit system. The fluid conduit system may be a flexible hose with a crimped on fitting or a pipe fitted with a threaded coupling, or any other conventional fluid conduit system.  
         [0016]    The dust plug  10  has a hollow center body  12 . The insertion end  14  of the plug  10  is tapered for easier insertion into a hose end. However, contrary to the conventional dust plug  100 , the insertion end  14  of the inventive plug  10  is a closed solid end. When the plug  10  is inserted into a coupling, the hollow body  12  communicates with the space outside of the conduit system rather than with the interior of the system (see FIG. 3).  
         [0017]    At the opposing end of the plug  10 , the plug  10  has a raised lip  16 . In the illustrated preferred embodiment, the lip  16  has a diameter D L  greater than the outer diameter D B  of the hollow body  12 . To make the lip  16  more readily graspable, the area  18  adjacent to the lip  16  preferably has a diameter D I  less than the diameter D B  of the hollow body  12 . The area  18  adjacent to the lip  16  may also have a constant increasing diameter from the outer diameter D B  of the hollow body  12  to the diameter D L  of the lip; creating a tapered configuration ending in lip  16 .  
         [0018]    The lip  16  may be formed as a discontinuous lip, so long as there is enough material provided to enable an operator to grasp the end of the plug  10 . The lip  16  may also be formed with a diameter D L  less than the outer diameter D B  of the hollow body  12 . If the lip  16  if formed with such a lesser diameter, than the area  18  adjacent to the lip  16  must have a configuration that enables the operator to be able to grasp the lip  16  to remove the plug  10  from a coupling.  
         [0019]    Similar to the conventional plug  100 , the inventive plug  10  is also provided with a means to enable the operator to mate the plug  10  to a coupling by means of a chain. The area  18  adjacent to the lip  16  may have at least one tab  20 . The tab  20  has a hole  21  through which a chain may be threaded. Since the tab  20  is integral with the plug  10  along multiple sides of the tab  20 , the tab  20  is stronger than the conventional removal means tab  120  and cannot be readily snapped off by tugging on the chain.  
         [0020]    Along the length of the hollow body  12  is a groove  22  for cooperation with the lever arm of a cam and groove fitting. The groove  22  is illustrated as continuous about the body  12 ; however, the body  12  may be provided instead with at least one discrete length groove for cooperation with a lever arm. If the dust plug  10  is to be employed in another type of fitting, i.e., not a cam and groove fitting, than the outer surface of the body  12  may have either a smooth continuous configuration or another configuration which mates with the fitting at the hose end in which the dust plug  10  is to be inserted.  
         [0021]    [0021]FIG. 3 illustrates the dust plug  10  after being inserted into a coupling unit  24  of a cam and groove fitting at the end of a hose  26 . The coupling unit  24  has been secured onto the hose  26  by means of a crimped-on ferrule  28 . The dust plug  10  is inserted into the coupling unit  24  with the insertion end  14  of the plug  10  sealing off the interior  30  of the hose  26 . The insertion end  14  abuts against an o-ring  32 , or other sealing means provided within the coupling  24 . The lever arms  34  are closed and parallel to the body of the coupling unit  24  so that the arcuate portion  36  of the lever arm  34  cooperates with the groove  22  of the plug  10 . Movement of the lever arm  34  from a perpendicular position relative to the coupling  24  to the illustrated parallel position pulls the plug  10  further into the coupling unit  24 , pushing the insertion end  14  against the o-ring  32 .  
         [0022]    Removal of the plug  10  is achieved by returning the arms  34  to a perpendicular position relative to the coupling unit  24  and then grasping the lip  16  to pull the plug  10  out of the coupling  24 .  
         [0023]    [0023]FIG. 4 illustrates the dust plug  10  after being inserted into a threaded cam and groove fitting  40 . Such a fitting  40  is threaded onto the end of a pipe or other threaded fluid conduit system. The plug  10  is inserted into the fitting  40  and abuts against the sealing means  42 . Because the plug  10  is compressed against the sealing means  42 , any fluid flowing through the fluid conduit system is retained within the system.  
         [0024]    The inventive dust plug  10  has several advantages over the conventional dust plug  100 . One advantage comes in the area of potential contaminants being introduced into the fluid conduit system. Since the insertion end  14  of the plug  10  is a flat solid surface, instead the opening of a hollow interior, any dirt that may collect in the hollow interior of the dust plug  10  is not transferred into the fluid conduit system. If any part of the insertion end  14  of the plug  10  does become dirty, it is easily cleaned by wiping the surface prior to inserting the plug  10  into a coupling  24 ,  40 .  
         [0025]    Another advantage of the plug  10  is achieved in the area of durability. Since the insertion end  14  is a solid plate of material, the insertion end  14  it is less susceptible to damage than the conventional ring-like plug end  114 . Also, in the preferred embodiment where the lip  16  has a diameter D L  greater than the outer diameter D B  of the body  12 , if the plug is dropped, the lip  16  will be struck first, minimizing or reducing any damage to the body  12 .  
         [0026]    A further advantage is achieved in the area of ease of removal of the plug  10 . After the conventional dust plug  100  is inserted into a coupling unit  24 ,  40 , the only portion of the plug  100  that is accessible for the operator to grasp to remove the plug  100  is the tab removal means  120 . If this is broken or damaged, it is difficult to remove the plug  100 . In all of the various disclosed embodiments of the inventive plug  10 , both the lip  16  and the area  18  adjacent the lip  16  extend past the end of the coupling  24 ,  40 , providing the operator ample material to grab onto and remove the plug  10  from the coupling unit  24 ,  40 .  
         [0027]    Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.