Abstract:
The splash-proof lid uses a capillary tube which is attached to the bottom of the lid and forms an angle of 60°. The arc capillary tube has two openings at each end which are in fluid communication with the drinking hole in the lid. The air hole is positioned at the center of the lid.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part application of U.S. patent application Ser. No. 09/095,419 filed Jun. 8, 1998, now abandoned. 
    
    
     BACKGROUND OF INVENTION 
     1. Field of Invention 
     This invention relates to a removable lid for a cup and, more particularly, to a lid which has both an air hole and a drinking hole through which a user can drink the liquid contents of the cup. The lid prevents inadvertent splashing which occurs due to unintentional movement of the cup. 
     2. Art Related to Invention 
     Splash-proof lids for drinking cups are known. Typically, they comprise a round, removable cover which fits tightly over the top opening of a cup to prevent unwanted spillage of the contents of the cup while allowing the user to drink the contents of the cup even though the lid remains on the cup. To allow the user to drink the contents of the cup while the lid remains on the cup, both a drinking hole and an air hole are provided in the lid. Both holes are configured to prevent unwanted loss or spillage of the contents of the cup which occurs when the cup is unintentionally moved. Typically, such lids are used on disposable cups which the user takes on a train, a plane, in a boat, or in a car. 
     The drinking hole is usually positioned at the edge of the lid next to the side wall of the cup, while the air hole is positioned either centrally in the lid or along the edge of the lid next to the side wall of the cup, opposite the drinking hole. 
     One example of such a lid is taught in U.S. Pat. No. 4,322,014. In the &#39;014 patent, a splash-proof lid has both a drinking hole and an air hole wherein both holes have a baffle arrangement to prevent the liquid contents of the cup from exiting the cup. The baffle arrangement is such that the axis of the baffle, taken along the fluid flow lines, forms a straight line and does not follow the contour or radius of the exterior of the lid. The baffle arrangement in the &#39;014 patent is rather complicated. 
     Another example of such a lid is taught in U.S. Pat. No. 4,394,928. Here a special cup having a ledge functions with the lid to form a curved channel through which liquid flows to the drink hole. Thus, a special cup must be employed to allow the lid to function. 
     There is a need for a simplified design for a splash-proof lid which can function with a conventional disposable cup. 
     SUMMARY OF THE INVENTION 
     A simplified splash-proof drinking lid for a cup has now been discovered. The lid is intended to be disposable and for use with disposable drinking cups such as the type used for coffee, tea, etc. The lid has an air hole and a drinking hole and is designed to avoid spillage of the contents of the cup through the drinking hole. 
     It has been discovered that the jiggling or unintended movement of the cup causes a wave to form on the surface of the liquid and to travel back and forth across the surface of the liquid crashing against the side walls of the cup. When the wave hits the side walls of the cup, it splashes out of the drinking hole or the air hole when the air hole is positioned next to the side wall of the cup. Thus, it is the movement of the waves on the surface of the liquid in the cup and its crashing against the side wall that causes the splashing and the spillage of the liquid. 
     It has also been found that when the air hole is made small and positioned in the center of the lid that splashing or spillage due to the wave through the air hole does not occur. Furthermore, it has been found that when the air hole is made rather small compared to the drinking hole, that the air hole will still function to allow liquids to flow out of the drinking hole and air in through the air hole. Thus, in the present invention, the air hole is positioned in the center of the lid and made relatively small compared to the drinking hole. To avoid spillage through the drinking hole, an arc capillary tube is employed. The arc capillary tube of the present invention has been found to redirect the liquid back into the cup and prevent spillage of the contents of the cup through the drinking hole. 
     The arc capillary tube is positioned on the bottom of the lid, directly below the drinking hole, and is in fluid communication with the drinking hole. The arc capillary tube follows the curvature of the lid and is centered on the drinking hole. The arc capillary tube is formed along the edge of the lid and has an opening at either end to allow for the liquid contents of the cup to travel into the capillary tube. The capillary tube is also in fluid communication with the drinking hole to allow the liquid contents to flow from the capillary tube through the drinking hole and into the user&#39;s mouth. The radius of the arc capillary tube is less than the radius of the lid and the radius of the arc capillary tube is concentric with the radius of the lid. 
     The lid itself has an engaging periphery to allow it to engage the rim of a cup and become removably affixed to the rim of the cup. In this way, the lid of the present invention fits a conventional disposable cup and no special arrangement need be made nor a special cup employed in the present invention. 
     Broadly, the splash-proof lid for a drinking cup in accordance with the present invention comprises: a circular disc having a snap fitting periphery for engagement with a cup rim; a drinking hole in said disc which is positioned adjacent to said snap fitting periphery; an air hole in said disc which is positioned in the center of said disc, said air hole being smaller than said drinking hole; and an arc capillary tube attached under said disc and centered on said drinking hole, said arc capillary tube being in fluid communication with said drinking hole, said arc capillary tube having a radius that is concentric with the radius of said disc and less than the radius of said disc, said arc capillary tube having two inlet openings, one at each end of said arc capillary tube, such that both inlet openings allow fluid communication between themselves and said drinking hole by means of said capillary tube. Preferably, the arc capillary tube forms an angle of 60°. More preferably, the arc capillary tube is rectangular in cross-section. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     These and other aspects of the present invention may be more fully understood by reference to one or more of the following drawings wherein: 
     FIG. 1 is a top view of the lid of the present invention; 
     FIG. 2 is a side view of the lid of the present invention; 
     FIG. 3 is a side view of the lid of the present invention rotated 90° from the view of FIG. 2; and 
     FIG. 4 is a cross-section of the lid of the present invention taken along lines IV—IV of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF INVENTION 
     FIG. 1 illustrates a top view of lid  10  which is a circular disc having raised center section  11  on top thereof, snap fitting periphery  12  along the sides thereof, drinking hole  14  extending therethrough, air hole  16  extending therethrough, and capillary tube  18  mounted on the bottom thereof. 
     Capillary tube  18  has two inlet openings  20  and  22 . Capillary tube  18  is in fluid communication with drinking hole  14  such that when a user drinks from cup  30 , the liquid contents of cup  30  flow through inlet openings  20 ,  22  into capillary tube  18  and through capillary tube  18  to drinking hole  14  and into the user&#39;s mouth. 
     As shown, capillary tube  18  is arced to form a 60° angle. Capillary tube  18  is centered on drinking hole  14  as shown in FIG.  1 . Capillary tube  18  is preferably rectangular in cross-section as shown in FIG. 4, however, it may take on other cross-sections. 
     Lid  10  is securely held on cup  30  due to the engagement between snap fitting periphery  12  and lip  32  of cup  30  when placing lid  10  onto cup  30 . Lip  32  is guided into snap fitting periphery  12  by edge  24 . Such an engagement is conventional and well-known to those of skill in the art. Snap fitting periphery  12  securely houses lip  32  as shown in FIG.  3 . 
     As a specific example of the present invention, the dimensions of lid  10  are as follows: 
     D 1 , diameter of raised center section  11 =55 mm. 
     D 2 , inside diameter of lid  10 =76 mm. 
     D 3 , outside diameter of lid  10 =85 mm. 
     D 4 , diameter of air hole. 
     R 1 , inner radius of capillary tube  18 =32 mm. 
     R 2 , outer radius of capillary tube  18 =37.6 mm. 
     H 1 , height of snap fitting periphery  12 =5 mm. 
     H 2 , height of edge  24 =4 mm. 
     H 3 , height of capillary tube  18  extending below edge  24 =4 mm. 
     H 2 +H 3 , height of capillary tube  18 =8 mm. 
     H 4 , height of raised center section  11 =2 mm. 
     W 1 , long width of drinking hole  14 =11 mm. 
     W 2 , short width of drinking hole  14 =5.4 mm. 
     W 3 , width of capillary tube  18 =5.6 mm. 
     These measurements are for one embodiment where the external diameter of the cup is 85 mm. Obviously, the dimensions of the lid are adjusted accordingly, depending on the size of the cup. As is typical, disposable cups are made generally in three sizes, small, medium and large, and the lid of the present invention is accordingly adjusted for these different cup dimensions. 
     The lid of the present invention is preferably made by molding a plastic material. The lid is preferably made in a single molding operation wherein a moveable die is used to form capillary tube  18 . The moveable die is moved after the molding operation to allow the removal of lid  10  from the mold. Such molding is conventional and is conducted in a conventional manner using conventional molding techniques. 
     Alternatively, capillary tube  18  can be separately molded and then affixed to the bottom of the disc which makes up the lid  10 . In order to do this, capillary tube  18  would be glued or affixed in a conventional manner to the bottom of lid  10 . 
     As can be appreciated by those of skill in the art, a single step molding operation is preferred and, in accordance with the present invention, a one piece molded plastic lid is made. 
     In accordance with the present invention, if any liquid is forced into capillary tube  18 , it will be sent back into cup  30  by redirecting the wave of the liquid. 
     As will be appreciated by those of skill in the art, the spill free lid of the present invention is easy to manufacture and is capable of nesting with other lids of like construction. The nesting is made possible because H 1  is greater than H 3 . Thus, the portion of the capillary tube  18  that extends below edge  24  will fit inside the portion of the lid defined by the inside diameter of lid  10  while edge  24  rests against the top of snap fitting periphery  12 . 
     As will also be appreciated, should any liquid exit from drinking hole  14 , it will be caught in the moat defined by raised section  11  and snap fitting periphery  12 . 
     It will be understood that the claims are intended to cover all changes and modifications of the preferred embodiment of the invention herein chosen for the purpose of illustration which do not constitute a departure from the spirit and scope of the invention.