Patent Publication Number: US-2007102388-A1

Title: Vented, low-drip nursing nipple

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates in general to nursing bottles and in particular to a nipple for a nursing bottle that vents the bottle when an infant is nursing and prevents drips when the infant is not nursing.  
      2. Description of Related Art  
      Although a need for nursing bottles may have arisen on Earth not long after the appearance of mammals, there is scant evidence in the archaeological record of attempts to fulfill that need prior to Roman times. Ceramic pitchers with nipple-like spouts have been found in ancient tombs of Roman babies. To feed an infant using this device would have required some dexterity and concentration, as it is necessary to insert the nipple into infant&#39;s mouth and tilt the pitcher when infant wanted to nurse and then quickly return it to upright when infant wanted to stop nursing. Any miscalculation as to the timing of the infant&#39;s intention to stop nursing, or an unexpected kick from infant, could result in a major spill. The infant may not have been completely happy with the device either, finding a cold, hard ceramic nipple a poor substitute for the real thing.  
      Despite the deficiencies of the Roman nursing bottle, there was little improvement to the basic design until the invention of the rubber nipple in the mid 19th century, one of the earliest and arguably most greatly appreciated applications of rubber. Examples of flexible nipples made of natural or synthetic rubber, plastic and other materials for nursing bottles are described in the following patents:  
      U.S. Pat. No. 22,579 issued Jan. 11, 1859 to Potter,  
      U.S. Pat. No. 26,327 issued Nov. 29, 1859 to La Forme,  
      U.S. Pat. No. 467,176 issued Jan. 19, 1892 to Jensen,  
      U.S. Pat. No. 605,161 issued Jun. 7, 1989 to Clement et al,  
      U.S. Pat. No. 586,011 issued Jul. 6, 1897 to Butz,  
      U.S. Pat. No. 589,212 issued Aug. 31, 1897 to Michael,  
      U.S. Pat. No. 785,707 issued Aug. 11, 1903 to Cantwell,  
      U.S. Pat. No. 1,099,082 issued Jun. 2, 1914 to Decker,  
      U.S. Pat. No. 5,035,340 issued Jul. 30, 1991 to Timmons,  
      U.S. Pat. No. 6,161,710 issued Dec. 19, 2000 to Dieringer, and  
      U.S. Pat. No. 6,250,487 issued Jun. 26, 2001 to Tebeau.  
      With the liquid fully enclosed except for a small slit or hole in the tip of the nipple sized to provide sufficient flow to the infant, it was no longer necessary for mother or nanny to be quite so attentive or skillful to avoid major spills.  
      A nursing bottle having an opening only in the nipple tip does have a drawback. As the infant draws liquid out of the bottle though the nipple, air in the bottle must expand to fill the void let by the departing liquid, thereby lowering the air pressure in the bottle. As the air pressure in the bottle continues to decline, the infant must suck harder on the bottle to remove additional liquid, until at some point the partial vacuum in the bottle has grown so strong the infant is no longer able to draw any more liquid out of the bottle. Although the infant need only stop nursing and calmly allow the bottle to draw additional air back into the bottle through the hole in the nipple tip, thereby relieving the partial vacuum, not all hungry babies have the foresight to do that. Some prefer to continue desperately sucking without success until, red-faced and frustrated, they give up and cry.  
      Sympathetic inventors have resolved this problem by providing a vent to permit air to enter the bottle to replace the departing liquid while the infant is nursing The following U.S. patents teach the use of a one-way valve in the bottom of the nursing bottle to vent the bottle as the infant nurses:  
      U.S. Pat. No. 362,554 issued May 10, 1887 to Suydam,  
      U.S. Pat. No. 1,037,309 issued Sep. 3, 1912 to Poore,  
      U.S. Pat. No. 2,084,099 issued Jun. 15, 1937 to Maccoy,  
      U.S. Pat. No. 3,768,683 issued Oct. 30, 1973 to Van Den Bosch,  
      U.S. Pat. No. 4,685,577 issued Aug. 11, 1987 to Chen,  
      U.S. Pat. No. 4,828,126 issued May 9, 1989 to Vincinguerra, and  
      U.S. Pat. No. 5,607,074 issued Mar. 4, 1997 to De Gennaro.  
      A bottle having a bottom valve is difficult and expensive to manufacture, and the valves may have small parts that are difficult to clean. The following U.S. patents describe a nursing bottle employing a disposable, collapsible bag in lieu of a rigid bottle for holding the liquid:  
      U.S. Pat. No. 3,718,140 issued Feb. 27, 1973 to Yamauchi,  
      U.S. Pat. No. 3,822,806 issued Jul. 9, 1974 to Grimes, and  
      U.S. Pat. No. 4,339,046 issued Jul. 13, 1982 to Coen.  
      Since the bag collapses as the infant nurses, there is no need to vent it. A less expensive approach is to provide one or more vents in areas of the nipple remaining outside the infant&#39;s mouth, as the infant nurses. The following U.S. patents teach variations on that approach:  
      U.S. Pat. No. 1,146,639 issued Jul. 13, 1915 to Miller,  
      U.S. Pat. No. 2,174,361 issued May 16, 1936 to Condon,  
      U.S. Pat. No. 2,616,581 issued Nov. 4, 1953 to Madsen et al,  
      U.S. Pat. No. 2,753,067 issued Jul. 3, 1956 to Rodrigues,  
      U.S. Pat. No. 2,942,746, issued May 31, 1957 to Porthouse et al,  
      U.S. Pat. No. 2,960,088 issued Nov. 15, 1960 to Witz,  
      U.S. Pat. No. 2,996,207 issued Aug. 15, 1961 to Witz,  
      U.S. Pat. No. 3,113,569 issued Dec. 10, 1963 to Barr et al,  
      U.S. Pat. No. 3,492,139 issued Feb. 18, 1970 to Faddoul et al,  
      U.S. Pat. No. 5,474,028 issued Dec. 12, 1995 to Larson et al,  
      U.S. Pat. No. 5,797,505 issued Aug. 25, 1998 to Kaura, and  
      U.S. Pat. No. 5,881,893 issued Mar. 16, 1999 to Manganiello.  
      When an infant is not nursing, liquid can leak out of a nursing bottle through the hole in the nipple tip. When the infant holds the bottle in his or her mouth without nursing, as for example when the infant falls asleep without releasing the nipple, continual leakage of milk or other liquid into the infant&#39;s mouth can cause tooth decay and other problems. Such leakage is particularly troublesome when the hole in the nipple tip is made relatively large to accommodate a flow rate sufficient for larger babies. One approach to reducing such leakage is provide an aperture in the nipple tip that opens to permit increased liquid flow when a infant is nursing and then substantially closes when the infant is not nursing to reduce the amount of leakage. One way to do that is to form a slit in an area of the nipple tip that is very thin and flexible. When the infant depresses the nipple and draws liquid through the slit, the slit opens to permit liquid flow, but when the infant stops nursing, the slit closes to reduce leakage. The following U.S. patents disclose this idea:  
      U.S. Pat. No. 2,688,326 issued Sep. 7, 1954 to Lerman, and  
      U.S. Pat. No. 3,718,140 issued Feb. 27, 1973 to Yamauchi.  
      This type of nipple tip can substantially reduce the amount of liquid that drips out of the tip of a non-vented bottle when an infant is not nursing since flow out of the tip is opposed by a residual partial vacuum in the bottle that tends to keep the slit closed. However since a vented bottle does not allow a partial vacuum to form within the bottle, leakage can occur though through even a relatively small slit. Liquid can also drip through a vented bottle&#39;s air vent when the vent does not provide a tight seal when the infant is not nursing.  
      U.S. Patent Publication No. 2004/0188373, based on a patent application filed Sep. 30, 2004 by Lewis et al, describes a nipple including a slitted nipple tip and an air vent in its nipple flange that seals when the air pressure inside the bottle is not substantially less than the air pressure outside the bottle to prevent leakage through the air vent when the infant is not nursing. Although the slit will close to prevent leakage through the slit when the air pressure inside and outside the bottle are equalized, leakage can occur through the slitted nipple tip if the bottle is flexible and the infant squeezes the bottle, thereby increasing the air pressure in the bottle and forcing the liquid through the slit.  
     BRIEF SUMMARY OF THE INVENTION  
      A nipple assembly for a nursing bottle in accordance with the invention includes a nipple having a slit at the bottom of a concave depression in its tip acting as a fluid outlet valve. The slit opens when a nursing infant deforms the nipple by squeezing it with its mouth and closes when the infant releases the nipple to prevent leakage. When the bottle is made of flexible material, the concave shape of the nipple tip tends to close the slit more tightly to prevent liquid from squirting out the slit when the infant increases pressure inside the bottle by squeezing it when not nursing.  
      The nipple includes a flange seated on the rim of the bottle and held in place by a cap having a central opening through which the nipple extends. A threaded ring on the cap engages the threaded bottle neck with the outer circumferential edge of the nipple&#39;s flange compressed between the annular top and the rim of the bottle. The nipple flange includes vent apertures between its inner and outer circumferential edges, and a raised annular bead between its inner circumferential edge and the aperture. The annular bead provides a seal between flange and the cap that prevents fluid from leaking out the vent apertures when air pressure within the bottle is not substantially lower than ambient air pressure. When the air pressure inside the bottle falls below ambient air pressure, the annular bead moves away from the cap to break the seal, thereby permitting air to pass through the central opening and into the bottle via the vent apertures.  
      The nipple includes one or more raised annular beads circumscribing its outer surface to provide tactile stimulation to a nursing infant and to improve the seal between the infant&#39;s lips and the nipple to limit fluid leakage 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an elevation view of a nipple in accordance with the invention.  
       FIG. 2  is an elevation view of the nipple of  FIG. 1  installed on a bottle.  
       FIG. 3  is a sectional elevation view of the nipple of  FIG. 1 .  
       FIG. 4  is a sectional elevation views of the nipple of  FIG. 1  installed on a bottle when air pressure outside the bottle is not substantially larger than air pressure inside the bottle.  
       FIG. 5  is sectional elevation views of the nipple of  FIG. 1  installed on a bottle when air pressure outside the bottle is substantially larger than air pressure inside the bottle.  
       FIG. 6  is a plan view of the nipple of  FIG. 1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The present invention relates to a nursing bottle having an air inlet aperture and a liquid outlet aperture that opens when an infant is nursing and closes to reduce leakage when the infant stops nursing. The nursing bottle also includes an air inlet valve that opens to vent the bottle when the infant is nursing and then closes when the infant stops nursing to inhibit liquid leakage. While the specification describes at least one exemplary embodiment of the invention considered to be a best mode of practicing the invention, the invention is not limited to the exemplary embodiment(s) described below or to the manner in which the exemplary embodiments operate.  
      Referring to  FIGS. 1-6 , nipple  10 , formed of resilient, flexible material such as natural or synthetic rubber or plastic, includes a hollow nipple body  12  having a distal end  14 , a proximal end  16  and an annular flange  18  attached to the proximal end of the nipple body. The distal end  14  of nipple body  12  includes a concave depression  20  extending downward toward its proximal end  16 . An outlet aperture formed by a small, thin slit  22  or hole at the bottom of depression  20  acts as a liquid outlet valve that opens when an infant deforms nipple body  12  while nursing, thereby allowing the infant to draw liquid through slit  22 . When the infant stops nursing on nipple body  12 , and stops deforming it, slit  22  closes to prevent liquid leakage. Slit  22  self-regulates flow rate based on how hard the infant sucks on nipple body  12 , and the length of slit  22  influences liquid flow rate. Slit  22  is suitably made relatively short for small babies demanding relatively low flow rates and relatively long for larger babies demanding relatively high flow rates. The flexible material in an area  24  surrounding slit  22  is preferably of reduced thickness in relation to that of other areas of the nipple body  12  to allow it more flexibility so that it opens wider when the infant sucks harder. Slit  22  is preferably Y-shaped as shown in  FIG. 6 , but may be other shapes.  
      Annular nipple flange  18  includes an inner circumferential edge  26  joined to the proximal end  16  of nipple body  12  and an outer circumferential edge  28  for engaging the rim  30  of a bottle  32 . A retainer cap  34  includes an annular top  36  with a central opening  38  through which nipple body  12  extends. Retainer cap  34  also includes a threaded annular ring  38  for engaging threaded bottle rim  30  to compress the outer circumferential edge  28  of nipple flange  18  between cap top  36  and bottle neck rim  30 , thereby providing a tight seal between nipple  10  and bottle rim  30 .  
      Apertures  40  in flange  18  between its inner and outer circumferential edges  26  and  28  provide passages for air to enter bottle  32  when a nursing infant reduces the air pressure within the bottle below ambient air pressure outside the bottle by drawing liquid from the bottle via slit  22 . Nipple flange  18  includes an annular bead  42  between its annular inner edge  26  and apertures  40 . When cap  34  is mounted on bottle rim  30  compressing outer circumferential edge  28  between cap top  36  and bottle rim  30 , the under side of cap top  36  presses down on bead  42 , deflecting flange  18  downward. Since flange  18  is made of resilient material, its deformation causes it to apply an upward force on annular bead  42  opposing the downward force applied by cap top  36 . The opposing forces hold annular bead  42  tightly against the under side of cap top  36  as illustrated in  FIG. 4 , forming a seal between annular bead  42  and cap top  36  preventing air or liquid from passing through apertures  40  and between cap top  36  and nipple body  12 .  
      When a nursing infant removes liquid from bottle  32  though slit  22 , the air pressure inside the bottle falls below ambient air pressure, creating a partial vacuum in the bottle that pulls nipple flange  18  downward, thereby breaking the seal between annular bead  42  and cap top  36  as illustrated in  FIG. 5 . With the seal broken, vent air  44  passes through a gap between cap top  36  and nipple body  12 , though the space between annular bead  42  and cap top  36 , through apertures  40  and into bottle  32  to relieve the partial vacuum in bottle  32 .  
      When the infant stops nursing, vent air  44  continues to flow into bottle  32  until the air pressure inside bottle  12  becomes sufficiently high relative to ambient air pressure to allow the upward force provided by deformed flange  18  to again push bead  42  into contact with cap top  36  to cut off further air flow into the bottle.  
      The liquid outlet valve formed by slit  22  in depression  20  and the air inlet valve formed by bead  42  and cap top  34  work thus together to regulate liquid flow out of bottle  32  and to prevent excessive loss of air pressure inside the bottle when the infant is nursing, and to substantially reduce or eliminate liquid leakage when the infant is not nursing. Slit  22  opens to permit liquid flow when the nursing infant sucks on and squeezes the nipple, and closes to substantially prevent liquid leakage when the infant stops nursing on the nipple. The air inlet valve formed by flange bead  18  and cap top  34  opens to allow vent air  44  to enter bottle  12  through apertures  40  when the infant nurses, but closes tightly under substantial pressure from deflected flange  18  to cut off the flow of vent air after the infant stops nursing.  
      Bottle  32  may be formed of a flexible material such as plastic, and when the infant is not nursing but is squeezing the bottle, the air pressure inside the bottle can rise above the ambient air pressure. The high air pressure in the bottle forces nipple body  12  upward to provide a tighter seal between annular bead  43  and cap top  36  to prevent liquid from escaping the bottle through inlet vent apertures  40 . The increased air pressure in bottle  32  also tends to push on depression  20  in a manner that causes slit  22  to close more tightly, thereby preventing liquid from escaping through the slit. When an infant squeezes a bottle having a conventional nipple of the type having a convex tip, the increasing air pressure in the bottle tends to open the slit in the tip, rather than close it, allowing the liquid to spray out Thus the combination of a slit in a concave depression at the distal end of the nipple acting as an outlet value, and the self-closing inlet valve mechanism of nipple  10  of the present invention allows an infant to easily draw liquid from the bottle when nursing and yet prevents liquid loss when the infant is not nursing, even when the infant squeezes the bottle.  
      Nipple body  12  includes a set of raised annular beads  50  circumscribing its outer surface provide a pleasing tactile simulation to the nursing infant. The beads  50  also help to provide a seal between the nipple body  12  and the infant&#39;s lips when nursing thereby reducing liquid seepage between the nipple body and the infant&#39;s lips.  
      Thus has been shown and described a nursing bottle nipple having a slitted, concave tip and an air inlet valve that open when infant nurses to allow liquid to flow out of the bottle and to allow air to flow into the bottle, and which close when the infant stops nursing to prevent liquid leakage even when the infant squeezes the bottle. The annular beads  50  surrounding nipple body  12  also help to reduce liquid spillage and provide the infant with pleasing tactile stimulation while nursing.  
      The foregoing specification and the drawings depict exemplary embodiments of the best mode(s) of practicing the invention, and elements or steps of the depicted best modes exemplify the elements or steps of the invention as recited in the appended claims. However the appended claims are intended to apply to any mode of practicing the invention comprising the combination of elements or steps as described in any one of the claims, including elements or steps that are functional equivalents of the example elements or steps of the exemplary embodiment(s) of the invention depicted in the specification and drawings.