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CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates to ball joints for showerheads. More particularly it relates to the provision of an air induction system associated with such ball joints to heighten the perceived water volume. 
         [0004]    Primarily for water conservation reasons the flow rate to conventional showerheads has been restricted. However, this can lead a consumer to perceive the shower as being less forceful than desired. 
         [0005]    It is known in connection with a variety of faucets and showerheads that aerating the water stream can make a given volume of water flow appear more bulky and substantial. Hence, aerating systems are often attached to the outlet of a faucet spout, and sometimes integrated into a showerhead. See e.g. U.S. Pat. Nos. 6,471,141 and 6,796,518 and U.S. patent application publications 2004/0199995 and 2007/0158470. 
         [0006]    However, associating the aeration system with the showerhead itself, or the faucet spout, can disrupt the aesthetics, and in some cases can add complexity to the manufacturing of the product. One such aerating low-flow showerhead accomplishes this through a variety of moving parts. Further, associating the aeration system with the showerhead itself does not provide a solution for aerating the millions of existing showerheads which don&#39;t have this capability. 
         [0007]    Hence, there were attempts to place the aeration system on a separate ball joint upstream of the showerhead, which would be hidden by the showerhead. See e.g. U.S. Pat. Nos. 5,111,994, 5,154,355 and 6,260,273, and U.S. patent application publication 2007/0193153. The approach used in these designs was to place a radial air inlet at the ball joint, and associate it with a venturi passage so as to induce air into the water flow in the joint. In this regard, as water passes through a throat of the venturi, the water velocity increases and the pressure decreases. The resulting negative pressure draws in ambient air through the radial inlet. The air then mixes with the water to produce an aerated water supply. 
         [0008]    These ball joint-related designs are not without their own drawbacks. For example, their air inlet ports are nothing more than uncovered holes formed in the water supply line. This creates the possibility of water leaking back out the air inlet, creating a path for water waste, spitback, or water spray into the main bath area. Further, designs of this type can create undesirable noise such as a whistling or a roaring sound. 
         [0009]    Hence, a need still exists for improved ways to aerate showerhead flow while avoiding these problems. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides a joint connector for linking a water supply to a showerhead. The joint connector has a housing having an inlet section at one end suitable to connect to a water supply pipe, an outlet section at an opposed end suitable to mount the showerhead thereon, and a central portion there between. There is a passageway extending axially through the housing from the inlet section, through the central portion, and through the outlet section. The passageway is suitable to carry water there through, and a portion of the passageway in the central portion forms a venturi. 
         [0011]    There is also an air inlet port positioned in the central portion and extending radially from the passageway to an exterior wall of the housing so as to be suitable to let air pass through the air inlet port into the housing. Further, an insert positioned within the air inlet port (e.g. to provide one-way flow and/or to reduce noise). 
         [0012]    In preferred forms of the invention the insert is in the form of a check valve that permits air flow through the inlet port into the passageway, but restricts reverse flow from the passageway through the inlet port. One such check valve is an elastomeric duckbill check valve. 
         [0013]    Surprisingly it has been found that this type of check valve greatly reduces noise associated with the joint while still controlling reverse flow through the air inlet. A particularly desirable placement for the intersection between the air inlet and the passageway is the throat of the venturi. Alternatively, noise reduction without check valve function can be obtained by using a cylindrical/sleeve form insert. 
         [0014]    Various refinements are also possible such as having the inlet section provided with a flat area on its upper exterior which extends to the air inlet port (to provide a hidden position for the insert), providing the inlet section with interior threads (to facilitate linkage to a water supply pipe), and providing the outlet section with a generally ball-shaped exterior (to facilitate mounting a showerhead for essentially universal pivoting). 
         [0015]    In another aspect the invention provides a showerhead mounted on such a joint connector. 
         [0016]    In some forms the passageway can have in the central section a portion that narrows in a conical fashion. This then leads to a narrowed cylindrical section to define a venturi throat. Water flowing through the passageway obtains a higher velocity through the throat than upstream of the throat. The passageway then expands sharply downstream of the throat. This causes a pressure drop at the throat, causing air to be sucked in past the insert. The air becomes mixed with the water supply to create the aerated water stream. 
         [0017]    It will be appreciated from the following description and the drawings that the present invention provides a number of advantages. First, because the air induction occurs at the ball joint, millions of existing showerheads can be retrofitted with this type of ball joint instead of the one they currently use. Hence, aeration can be provided for them. 
         [0018]    Also, there is no spurting or leaking of water back out the air inlet port. Also, the air inlet port and associated insert are essentially hidden from view. 
         [0019]    Further, the problem of noise due to air induction is overcome. Moreover, all these advantages can be obtained without materially increasing the cost of a standard ball joint. 
         [0020]    These, and still other advantages, can be obtained with the present invention. While preferred embodiments are described below, the claims should be looked to in order to judge the full scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a side elevational view of a joint connector of the present invention linking a water supply pipe and a showerhead; 
           [0022]      FIG. 2  is an exploded perspective view of the joint connector of  FIG. 1 ; and 
           [0023]      FIG. 3  is a cross sectional view taken along line  3 - 3  of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    Ball joint connector  10  is shown threaded onto a conventional water supply line  12 . The ball joint connector  10  has a generally tubular outer housing which has an inlet portion  14  and an outlet portion  16  which is generally ball-shaped. The intermediate portion there between houses an internal venturi and an air inlet port  34 , as well as an axially extending passageway  18 . 
         [0025]    A passageway inlet  20  is located at an upstream end of the ball joint connector  10 , and a passageway outlet  22  is located at the opposing downstream end. When installed as shown in  FIGS. 1 and 3 , the passageway  18  carries water from the water supply line  12  to a conventional showerhead  24 . 
         [0026]    The ball joint connector  10 , apart from the insert  40 , is preferably made of a metal such as brass. Standard internal threads  26  are provided in the passageway inlet  20  and are designed to threadingly engage the water supply line  12 . The showerhead  24  can be movably secured to the outlet portion  16  in a known manner so as to be easily swiveled (compare the mounting system of U.S. Pat. No. 6,796,518). 
         [0027]    The passageway  18  includes a venturi entry section  28  that provides a taper (preferably conical) to speed up the flow through a venturi throat  30 . Downstream of the venturi throat  30 , the passageway  18  has a venturi exit cone  32  to expand flow outwardly. The passageway  18  may further include a pocket section within which a flow regulator and/or a filter screen may be placed. The passageway  18  may further include a pocket section within which a flow regulator and/or filter screen may be placed. 
         [0028]    When water flows through the passageway  18 , the reduction provided by the venturi entry cone  28 , throat  30 , and exit cone  32  causes the velocity of the water to increase and the pressure to decrease. This phenomenon is well known in the art and often referred to as the Bernoulli principle. 
         [0029]    The ball joint connector  10  has a radially extending air inlet port  34 . An elastomeric insert in the form of a duck bill type check valve  36  is situated within the air inlet port  34 . The reduced water pressure in the venturi throat  30  is less than the pressure of the ambient air when water is rushing through the ball joint connector  10 . Due to the resulting pressure difference, ambient air is drawn into the passageway  18  through the air inlet port  34  and becomes inducted, or entrained, into the water stream contained therein. 
         [0030]    The air inlet port  34  as shown extends transversely between the water supply passageway  18  and a flat outer upper surface portion  38  of the ball joint connector  10 . Alternatively, the air inlet port  34  may extend at an acute angle. The flat outer upper surface portion  38  also facilitates use of a gripping wrench. When installed as shown in  FIG. 3 , an inlet end  46  of the check valve  36  is flush with the flat outer upper surface portion  38 . 
         [0031]    Still referring to  FIG. 3 , the air inlet port  34  joins the passageway  18  at the venturi throat portion  30 . The entry point of the air inlet port  34  could alternatively be formed in other locations in the passageway  18 . 
         [0032]    In the embodiment shown, the elastomeric check valve  36  is force fit into the air inlet port  34  and through which air flows into the passageway  18 . The check valve  36  permits the flow of air into the passageway  18  while preventing water (or air) from discharging out of the passageway  18 . The preferred check valve design, as shown in  FIGS. 2 and 3 , is commonly referred to as a “duckbill” valve because its outlet end  42  has a pair of lips  44  that taper like the bill of a duck. 
         [0033]    The check valve  36  has a cylindrical flange at its inlet end  46  configured to fit snugly within the air inlet port  34 . A central bore  48  extends completely through the check valve  36 . Air drawn into the bore  48  acts to drive the flexible tapered lips  44  apart, thereby permitting air flow into the passageway  18 . Pressure applied against the outlet  42  of the check valve  36  acts to drive the lips  44  closed and prevent reverse flow through the check valve  36 . 
         [0034]    When first starting a shower, the check valve  36  prevents the initial surge of water from discharging out of the air inlet port  34 . Similarly, if the venturi-induced vacuum is interrupted, such as by air trapped in the line, the potential exit path provided by the air inlet port  34  is blocked by the one-way nature of the check valve  36 . 
         [0035]    Surprisingly, the check valve  36  further acts to substantially reduce the level of noise. If the ball joint connector were used without an insert such as check valve  36 , a shrill whistling or roaring noise is oftentimes produced. The noise level has been measured as high as ninety-five decibels just outside of the air inlet port  34 . 
         [0036]    However, it has been found that by placing a small sleeve-like insert within the air inlet port  34 , the noise emanating from the ball joint connector  10  can be greatly reduced. It is believed this is occurring because a flexible sleeve absorbs and limits the sound waves, while still permitting air passage. 
         [0037]    It should be appreciated that merely preferred embodiments of the invention have been described above. However, many modifications and variations to the preferred embodiments will be apparent to those skilled in the art, which will be within the spirit and scope of the invention. For example, the insert could be a rubber cylindrical sleeve, rather than a rubber or other elastomeric check valve. Therefore, the invention should not be limited to the described embodiments. To ascertain the full scope of the invention, the following claims should be referenced. 
       INDUSTRIAL APPLICABILITY 
       [0038]    The invention provides a ball joint-type connector for linking a showerhead to a water supply pipe, where the connector provides aeration function with reduced noise and water waste.

Summary:
A ball joint connector is provided for linking a showerhead to a water supply pipe. The connector has an internal venturi that draws air into the connector to aerate water being provided to the showerhead. An insert such as a check valve is provided in a radial air inlet connected to the venturi. The insert prevents spraying or leaking out the air inlet, while reducing noise associated with the air induction.