Patent Publication Number: US-7210591-B2

Title: Nipple with a compromisable seal for a baby bottle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of International Application Number PCT/US02/25383, filed Aug. 9, 2002, and U.S. Provisional Application Ser. No. 60/311,219, filed Aug. 9, 2001, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates to a nipple for a baby bottle. 
     BACKGROUND 
     A wide variety of baby bottle nipples exist. The nipples can typically be coupled to a container storing a fluid, such as milk, formula, juice or water. These nipples are typically somewhat elastic and include a hole to allow passage of the fluid from the container to a baby. 
     Fluids can be delivered to a baby, for example, by using commercially available nipples secured to a container of fluid or by allowing a baby to suckle directly from a breast of a nursing mother. 
     Improvements are continually sought in the design of artificial bottle nipples to try to replicate the function and feel of the natural nipple, in part to help ease transitions between breastfeeding and bottle feeding. 
     SUMMARY 
     In one broad aspect of the invention, a nipple for use with a baby bottle includes a flexible outer member and an inner member. The outer member has an annular securing flange and a central membrane portion extending from the securing flange to define an aperture at a nursing end thereof. The central portion has an inner surface and a flexible flap extending inwardly from the inner surface. The inner member has a flexible membrane portion positioned at least partially within the central portion of the outer member and defines a valve passage arranged to be selectively obstructed by the flap. The outer member and the inner member define between them a holding chamber having the valve passage as an inlet and the aperture as an outlet. The flap is positioned on a side of the passage nearest the holding chamber to inhibit flow from the holding chamber through the passage when the outer membrane is compressed to collapse the holding chamber, and to deflect away from the passage to allow the holding chamber to receive a fluid through the passage when the outer membrane is released. 
     In some cases, the flap defines a hole and is manually positionable to align the hole with the valve passage to establish a hydraulic communication path into the holding chamber. In some such cases, the membrane portion of the outer membrane member has an outer exposed surface with a delineated region adjacent the flap, the delineated region of the outer member being manipulable to move the flap to align the hole with the valve passage. 
     Preferably, the holding chamber includes a first section that receives the fluid when the outer membrane is released; a second section in hydraulic communication with the aperture; and a compromisable seal disposed between the first and second sections. The seal prevents passage of fluid when the membrane of the outer membrane member is in a relaxed position, and allows passage of fluid when the membrane of the outer membrane member is compressed to collapse the holding chamber. In some instances the compromisable seal is defined by an annular portion of the membrane of the outer member that contacts an annular portion of the membrane of the inner member. 
     In some embodiments the aperture provides a hydraulic communication path for passing fluid out of the holding chamber when the membrane of the outer membrane member is compressed. 
     The aperture may be in the form of a slit, for example, in the outer membrane, that opens to allow passage of fluid when the outer membrane is compressed and closes to prevent passage of fluid when the outer membrane is in a relaxed position. 
     In a presently preferred embodiment, the nipple has a plurality of valve passages, and a plurality of corresponding flaps, with each valve passage selectively obstructed by a corresponding flap. Preferably two of the flaps, positioned opposite each other, define priming holes and are manipulable to align their priming holes with respective valve passages to establish a hydraulic communication path into the holding chamber. More preferably, the outer membrane further has an outer surface with a delineated region adjacent each hole-defining flap, each delineated region being manipulable to move the associated flap to align the associated hole with the associated passage. 
     The membrane of the inner member preferably is of a hardness of about 50 shore A, and the membrane of the outer member is preferably of a hardness of about 55 shore A. 
     In a preferred constructions, the inner member includes a rigid base ring from which the flexible membrane of the inner member extends. Preferably, the membrane of the inner member is formed of a flexible material that extends across a lower surface of the base ring to form a gasket seal for engaging an upper rim of a bottle. The base ring, in some cases, defines recesses arranged to receive alignment features of the outer member, to rotationally align the inner and outer members. 
     The inner and outer members may also be integrally formed (e.g., molded) of a single resin. 
     It is preferred that at least the membrane of the inner member be removable from within the outer member, such as for cleaning or for use of the outer member as a standard nipple. More preferably, the two members are completely separable for cleaning and/or replacement. 
     In some embodiments, corresponding alignment patterns are provided on the annular securing flanges of the inner and outer members, such that relative positioning of the patterns indicates a degree of rotational alignment between the inner and outer members. 
     In some cases, the aperture is positioned offset from an axial centerline of the outer membrane by a distance (e.g., of between about 1 and 15 millimeters) measured along the contour of the nipple. 
     In some cases, the membrane of the inner member defines an orifice sized to pass a small amount of fluid when suction is applied to the aperture of the membrane of the outer member. 
     Another aspect of the invention features a bottle for feeding a baby. The bottle includes a container for holding a fluid that has an open end for passage of the fluid, a nipple as described above, and a securing device positioned to mate with the securing flange of the outer member of the nipple to secure the nipple to the open end of the container. 
     Another aspect of the invention features a method of delivering fluid to a baby. The method includes securing a nipple (as described above) to an open end of a container holding a fluid, and positioning the aperture of the nipple inside a baby&#39;s mouth, thereby enabling the baby&#39;s mouth to apply a compressive force to the outer membrane to collapse the membrane of the outer member to force fluid from the holding chamber, through the aperture. The baby&#39;s mouth can then release the outer membrane, thereby enabling the holding chamber to receive more fluid from the container through the valve passage. 
     In some cases the method includes, preferably prior to positioning the aperture of the nipple inside the baby&#39;s mouth, manually priming the nipple. Priming the nipple includes, in some cases, positioning the container so that the fluid is in contact with the nipple and manually manipulating a delineated region on an outer surface of the outer member, such as by compressing the delineated region, to move the flap to align a hole in the flap with the passage. In some instances priming the nipple includes allowing fluid to flow from the container, through the valve passage, through the hole in the flap and into the holding chamber while the hole remains aligned with the valve passage. The delineated region may be released to return the flap to a position with its hole offset from the valve passage and the flap obstructing the passage. 
     In some applications, securing the nipple includes aligning rotational alignment features of the inner and outer members to place the inner and outer members in operative relative alignment. 
     Yet another aspect of the invention features a method of priming a nipple for a baby bottle. The method includes securing one of the above-described nipples to an open end of a container holding a fluid, orienting the bottle so that the fluid is in contact with the nipple, and applying a compressive force to the delineated region of the outer member to deform the outer member in such a manner that the hole of the flap aligns with the valve passage of the inner member. 
     The term static, as used herein to describe a condition associated with a nipple, should be understood to include any condition that the nipple or any component of the nipple is not under the influence of any externally applied forces as might be applied by a mother or a baby. 
     Implementation of the techniques and apparatus described herein may provide one or more of the following advantages. A nipple may be provided that can closely approximate the function and response of a mother&#39;s nipple when breastfeeding. Babies may be more comfortable learning how to be fed by a bottle after having been breastfed. Transitioning a baby from a regimen including breastfeeding to a regimen including bottle feeding may be made less traumatic for the baby and easier for the parent teaching the baby. Implementations including a compromisable seal can desirably minimize the amount of fluid that might leak from the nipple in the event that the baby bottle is, for example, dropped or knocked over. 
     Other advantages and aspects will be apparent from the following disclosure of embodiments and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a partial exploded side view of a baby bottle assembly. 
         FIG. 2A  is a cross-sectional view of the assembled nipple shown in  FIG. 1 . 
         FIG. 2B  shows a version of the nipple assembly without a compromisable seal. 
         FIG. 3A  shows the nipple assembly in a static condition. 
         FIG. 3B  shows the nipple assembly during priming. 
         FIGS. 4A–4C  sequentially illustrate nipple insertion into a baby&#39;s mouth and suckling. 
         FIG. 5A  is a bottom view of the outer member of the nipple of  FIG. 1 . 
         FIG. 5B  is a bottom view of the inner member of the nipple of  FIG. 1 . 
         FIG. 6A  is a cross-sectional view of a second nipple, with the inner and outer members unitarily molded, in an as-molded condition. 
         FIG. 6B  shows the nipple of  FIG. 6A , with the outer member inverted about the inner member for use. 
         FIG. 7  is a cross-sectional view of a nipple with a hole at the end of the inner member. 
         FIG. 8  is a side view of another nipple assembly. 
         FIG. 9  is a cross-sectional view, taken along line  9 — 9  in  FIG. 8 . 
         FIG. 10  is a perspective view of the inner member of the nipple of  FIG. 8 . 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     As shown in  FIG. 1 , a baby feeding assembly  100  includes a container  102  for holding a fluid, such as milk or water. A nipple  104  mates with an open end of the container  102  and a securing device  106  secures the nipple  104  to the open end of the container  102 . 
     The nipple  104  includes an inner member  110  and an outer member  112 . When assembled, the inner member  110  is positioned at least partially within the outer member  112 . The outer member  112  may also be installed on the bottle without the inner member, for use as a standard one-piece nipple. 
     The securing device  106  has threads  113  disposed on an internal surface that can mate with corresponding threads  108  on an outer surface on the container  102 . The nipple  104  can be positioned between the securing device  106  and the container  102 . The securing device  106  can be fastened to the container  102 . When so assembled, an internal collar  114  of the securing device  106  contacts an annular flange  116  of the outer member  112  to compress it and also to compress an annular flange  118  of the inner member  110 , thereby securing the nipple  104  to the container  102 . Other securing techniques known to those possessing ordinary skill in the art may be possible. 
     Alignment marks  120   a ,  120   b  are provided on securing flanges  116 ,  118  of both the outer membrane  112  and the inner membrane  110 . When assembled, the alignment marks  120   a ,  120   b  of each flange  118 ,  116  should align with each other. The alignment marks  120   a ,  120   b  can provide an indication that the inner member  110  and the outer member  112  are in proper relative alignment with each other. 
       FIG. 2A  shows the assembled nipple  104  in a static condition. The nipple  104  is securely fastened to a container  102  by securing device  106 . The annular securing flange  116  of the outer member  112  is in contact with the annular securing flange  118  of the inner member  110  and the inner member  110  is positioned partially within the outer member  112 . The outer member  112  includes a central membrane portion  202  that extends from the securing flange  116  to define an aperture  204  at the nursing end. The aperture  204  could be, for example, a centrally disposed hole positioned at an intersection of an axial centerline  206  of the nipple  104  and membrane  202  to allow passage of fluid from the container  102 . Alternatively, the aperture  204  could be a slit in membrane  202 . The slit could, for example, open to allow passage of fluid when the membrane portion of the outer member is compressed, and close to inhibit passage of fluid when the outer member is in its static position. The slit could be configured, for example, with an I-shape or an X-shape. 
     Optionally, one or more apertures  204  could be disposed a distance off-center from the intersection of the longitudinal axis  206  of the nipple with outer member membrane portion  202 . Offsetting the aperture in this manner may be desirable to prevent fluid that exits the aperture  204  from being directed towards a baby&#39;s throat. An aperture  204  may be displaced, for example, between about 0 millimeter and 15 millimeters from the intersection of the longitudinal axis  206  with membrane  202  as measured along the contour of the membrane. More preferably, apertures  204  may be displaced between about 0 and 5 millimeters, and most preferably may be displaced between about 2 and 4 millimeters from the centerline of the nipple. Additionally, aperture  204  may be displaced from the intersection of the longitudinal axis and the outer membrane by an angle measured from a point along the longitudinal axis inside the outer member that is approximately 15 millimeters from the outer member. The apertures are preferably positioned such that the angle is between about 0 degrees and 90 degrees (more preferably between about 0 and 30 degrees and most preferably between about 5 and 15 degrees). 
     The central membrane portion  202  of outer member  112  has an inner surface  208  from which flexible flaps  210  extend inwardly. The inner member  110  includes valve passages  216  that can be selectively obstructed by corresponding flaps  210  extending from the outer member  112 . In this embodiment, flaps  210  include a hole  226  that, in a static state, is axially offset from a corresponding passage  216 , but can be manually shifted to prime the nipple. 
     Inner member  110  has a central membrane portion  111  extending into the membrane portion  202  of the outer member  112 . 
     The outer surface  212  of the outer member  112  includes two delineated regions  214 , each positioned on an opposite side of the nipple  104 . The delineated regions  214  are adjacent to and associated with corresponding flaps  210  that define priming holes  226  and are raised from the surrounding surface of the outer membrane for easy manual manipulation. 
     The securing flange  118  of the inner member  110  includes vent holes  228 , positioned annularly at intervals annularly around the perimeter of the securing flange  118 . Corresponding vent holes  230  are provided in the outer member  112  to be aligned with the vent holes  228  of the inner member  110  to define a sealable path for passage of air. If so provided, the path should be sufficiently narrow to prevent inadvertent leakage of fluid out of the container. As fluid exits the container  102  through valve passages  216 , a low pressure region is created within the container. If a sufficient pressure difference is created between the external atmospheric pressure and a container  102 , the vent path should allow for the passage of air into the container to equalize the pressure difference. Other venting arrangements are possible and will be apparent to one possessing ordinary skill in the art. 
     The inner member  110  and the outer member  112  can be fabricated using flexible, safe, non-toxic materials. Suitable materials include, for example, thermoplastic elastomers (TPE) and silicone. Silicone is preferred for outer member  112 . 
     Inner member  110  has a substantially uniform material thickness throughout. Alternative arrangements may include inner members having a thickness that varies throughout. The thickness of inner member  110  material typically ranges between about 0.020 inch (0.5 millimeter) and 0.100 inch (2.5 millimeters), but is more preferably between about 0.060 inch (1.5 millimeters) and 0.080 inch (2.0 millimeters). 
     Preferably, the delineated regions  214  of outer member  112  are structurally reinforced and more rigid compared to other portions of the outer member  112 . Accordingly, the thickness of delineated regions  214 , as measured at the area indicated approximately by the arrows  232 , is preferably between about 0.060 inch and 0.100 inch (between about 1.5 and 2.5 millimeters), but is more preferably about 0.080 inch (2.0 millimeters). The other portions of the outer member  112  (i.e., not delineated regions  214 ) preferably have a uniform thickness that ranges from about 0.020 inch (0.5 millimeter) to about 0.050 inch (1.3 millimeters), but more preferably ranges from about 0.030 inch (0.8 millimeter) to about 0.040 inch (1.0 millimeter). 
     In some implementations, it may be desirable for the membrane portion of inner member  110  to be more rigid than nominal portions (e.g., any portion other than delineated regions  214 ) of the membrane portion of outer member  112 . 
     Referring now to  FIG. 2B , outer member  112  and inner member  110  define a holding chamber  218  between them. The holding chamber  218  has valve passages  216  as inlets and aperture  204  as an outlet. The flaps  210  are positioned on a side of passages  216  closest to the holding chamber  218  and may, in fact, be positioned within the holding chamber  218  proper. The holding chamber  218  can be a single contiguous space with fluid being allowed to flow freely throughout all areas of the holding chamber  218 . 
     In some cases, as shown in  FIG. 2A , a compromisable seal  224  is defined by an annular portion of the membrane portion  202  of outer membrane  112  contacting a corresponding annular portion of the membrane portion of inner member  110  to create a fluid-tight and air-tight seal  224  when the nipple  104  is in a relaxed state. The compromisable seal  224  divides the holding chamber  218  into a first section  220  and a second section  222 . The first section  220  is able to receive fluid directly from the container  102 , through valve passages  216 . The second section  222  is in direct hydraulic communication with aperture  204  and can receive fluid from the first section  220  when the seal  224  is compromised, such as when the outer membrane  112  is compressed or otherwise deformed. 
     Referring now to  FIG. 3A , nipple  104  is secured to a container  102  with a securing device  106 . The container  102  is holding a fluid. The flaps  210  are positioned to obstruct valve passages  216  and thereby prevent the flow of fluid from the container into the holding chamber  218 . The holding chamber  218  is initially void of fluid. 
     Prior to delivering fluid to a baby, nipple  104  may require priming to initially introduce an amount of fluid into the holding chamber  218 , preferably to completely fill holding chamber  218 . Priming may not be required in all applications. 
     Referring now to  FIG. 3B , each delineated region  214  can be manually manipulated by applying a force, for example by compressing the opposing delineated regions  214  of nipple  104  between thumb and forefinger, in a direction indicated by the arrows  302 . Applying such a force causes the delineated regions  214  to move inwardly, thereby moving their associated flaps  210  so that corresponding holes  226  in the flaps  210  align with valve passages  216  in inner member  110 . This establishes a hydraulic communication path between the container  102  and the holding chamber  218 . Fluid can flow freely from the container  102  into the holding chamber  218  as indicated by the arrows  304  as long as holes  226  and valve passages  216  are held in alignment. 
     When the applied force is released, the outer member regains its original shape and flaps  210  return to their original positions to obstruct passages  216 , as in  FIG. 3A . The holes  226  in the flaps  210  are once again offset from their associated valve passages  216  in the inner member  110 . The flaps  210  return to their original positions due to the elasticity of the flexible portion of the outer member  112 . 
     Referring now to  FIG. 4A , a caregiver can position aperture  204  of the primed nipple  104  inside a baby&#39;s mouth  402  to enable the baby to draw fluid from nipple  104 . The illustrated container  102  is holding a fluid, and the holding chamber  218  of the nipple  104  is fully primed with fluid. The flaps  210  are positioned to prevent passage of fluid from the holding chamber back into the container  102 , through valve passages  216 . 
     Turning to  FIG. 4B , with the nipple  104  so positioned, the baby can apply a compressive force to the outer member  112  with its gums  403 , in a direction indicated approximately by arrows  404 . The compressive force collapses the holding chamber  218 , reducing its volume and forcing fluid from the holding chamber  218  through aperture  204  and into the baby&#39;s mouth  402 . The flaps  210  remain positioned to obstruct valve passages  216 , thereby preventing fluid from flowing back into container  102  while holding chamber  218  is being collapsed. Rolling of the baby&#39;s tongue  405  against the outer member  112  can further force fluid toward the aperture in a manner similar to the natural mechanisms of drawing milk from mammory gland ducts during breastfeeding. 
     In implementations in which the holding chamber is divided by a compromisable seal  224 , applying the compressive force in a direction indicated by arrows  404  also opens the compromisable seal at least at two positions about the perimeter of the inner member, thereby allowing fluid to flow in a direction indicated by arrows  410  between the first portion  220  of the holding chamber  218  and the second portion  222  of the holding chamber  218 . 
     Referring now to  FIG. 4C , when the baby&#39;s gums  403  and/or tongue  405  sufficiently reduce or release the compressive force, the outer member  112  moves in a direction indicated by arrows  406  to restore at least some of the displaced volume of the holding chamber  218 . This action creates a low-pressure region within the holding chamber  218 , relative to container  102 , that causes the flaps  210  to deflect away from valve passages  216  to establish a hydraulic communication path between the container  102  and the holding chamber  218 , pulling fluid from container  102  through passages  216  to holding chamber  218 , as indicated by arrows  408 . Fluid continues to flow in this manner until the pressure differential across passages  216  is substantially equalized. After the pressure is substantially equalized between container  102  and holding chamber  218 , flaps  210  reseat against passages  216  to prevent passage of fluid from container  102  into the holding chamber  218 , and the next suckling cycle repeats as in  FIG. 4B . 
     In some implementations, when the compressive force is released by the baby&#39;s mouth  402 , the compromisable seal  224  is reestablished between the first portion  220  of holding chamber  218  and the second portion  222  of holding chamber  218 . This action can effectively isolate the first portion  220  of holding chamber  218  from aperture  204 , and thereby minimize undesirable entrance of air through aperture  204  into holding chamber  218  when outer member  112  is released. 
     Referring now to  FIG. 5A , four flexible flaps  210  are located at equal intervals around the perimeter of, and project inwardly from, the inner surface  208  of outer member  112 . The outer member can include more or fewer flaps than illustrated. Two of the flaps  210  define holes  226  for priming the nipple. Regardless of how many flaps  210  are included in a particular implementation, preferably only two include holes  226 . The two flaps  210  with holes  226  are positioned opposite each other in alignment with priming pads  214  ( FIG. 1 ). This arrangement enables a user to prime the nipple by applying a relatively simple squeezing force with, for example, a thumb and a forefinger. Each flap  210  with a hole  226  is located adjacent a delineated region  214 , which provide a means for manipulating flaps  210  to change the positions of holes  226 . 
     Two vent holes  230  are also provided in securing flange  116 . An alternative arrangement could include, for example, a channel extending around the perimeter of securing flange  116  and vent holes passing from the channel through the securing flange  116 . Other vent arrangements are also possible. 
     The securing flange  116  includes alignment marks  120   a  to assist a user in aligning the outer membrane  112  with the inner membrane. 
     Referring also to  FIG. 5B , the securing flange  118  of inner member  110  includes alignment marks  120   b  for aligning the inner member with a corresponding outer member. The relative positioning of the alignment marks in an assembled nipple determine the degree of radial alignment between the inner and outer members. Other patterns or features may be provided to facilitate aligning inner and outer members of the nipple, which may be required in some configurations to ensure that the flaps or other flow blocking features of the outer member correctly line up with passages  216 , and also to ensure that vent holes  228 ,  230  align properly. Preferably, marks  120   a  ( FIG. 5A) and 120   b  of the inner and outer members comprise mating physical features of the two parts that disallow assembly unless the two pieces are in proper alignment, such as discussed further below. Such mating features may include, for example, male/female type connections. 
     Four valve passages  216  are defined by inner member  110 , positioned at equal intervals around the perimeter of an annular portion of the inner member. When a nipple is assembled, a flap of the outer member normally blocks each passage in a static condition. 
     As shown in  FIG. 6A , nipple  104   a  can be fabricated as a single integrated structure. Such a structure can be unitarily molded with a connector  602  disposed between the outer membrane portion and the inner membrane portion. The outer membrane portion is shown as molded, and must be inverted to create a functional apparatus, as shown in  FIG. 6B . The aperture  204  is offset from an axial centerline  604  of the nipple  104   a  to allow the connector  602  to be configured as shown. Alternative connector  602  configurations may be possible. Alignment marks are not included, because the outer membrane portion remains securely fastened to the inner membrane portions at all times. The connector  602  can ensure proper radial alignment between the outer membrane portion and the inner membrane portion. 
     Turning now to  FIG. 7 , in certain implementations it may be desirable to provide a small orifice  702  near the tip of the inner member to allow a small amount of fluid to pass through when suction is applied to aperture  204 . Orifice  702  is preferably small enough to inhibit the passage of significant amounts of fluid, but provides a means for removing the small amount of fluid that may remain within the conical portion of the inner member and not readily pulled through passages  216  into the holding chamber. In such cases, the primary means of dispensing fluid from the nipple remains the peristaltic pumping action of the cyclic deformation of the holding chamber, orifice  702  providing only a supplemental flow insufficient to interfere with the pumping function. 
     In some cases, orifice  702  also serves as an internal pressure regulator during suckling. Excess pressure in the holding chamber causes some return flow into the bottle through orifice  702 , limiting the fluid delivered to the baby. This can help to avoid strong fluid sprays directly down the baby&#39;s throat. The size of orifice  702  can be selected to increase or decrease this effect, as desired. 
     We have found that an orifice  702  of about 0.010 inch (0.25 millimeter) in diameter can provide sufficient initial flow into the holding chamber upon initial inversion of the bottle that manual priming is unnecessary, the suckling action of the baby being sufficient to initiate flow and subsequently fill the holding chamber. 
       FIGS. 8–10  show another nipple assembly. Referring first to  FIGS. 8 and 9 , nipple assembly  800  includes separable inner and outer components  810  and  812 , generally as described above. In the cross-section of  FIG. 9 , the flexible portions of the nipple assembly are shown in their relaxed state, with overlap between the two parts indicating where the flexible membranes and flaps are preloaded in the assembly. Outer component  812  is molded entirely from silicone to have a durometer of about 55 shore A. Flap valve holes  226  are oval, with overall dimensions of about 1.6 millimeters by 2.4 millimeters. 
     Referring also to  FIG. 10 , inner member  810  consists of a central membrane  814  of thermoplastic elastomer (TPE) overmolded onto a rigid polypropylene base ring  816 . Base ring  816  defines oval valve holes  216  and provides a stable surface for engaging the flexible valve flaps  210  of outer member  812 . Valve holes  216  each measure about 1.6 millimeters by about 2.6 millimeters, and are completely blocked by flaps  210  of the outer member with the assembly at rest. As in the above-described embodiment, the valve holes  216  of rigid base ring  816  of the inner member at least partially align with flap valve holes  226  of the outer member when the outer member is squeezed at finger pads  214 , such as for priming. Base ring  816  also defines four recesses  818 , arranged at 90 degree intervals about the periphery of the inner member, for receiving corresponding vertical alignment ribs  820  of the outer member. The rigidity of base ring  816  thus helps to secure the alignment between the two members, in any of four functional orientations. The overmolded TPE extends under the peripheral flange  822  of the base ring, as shown in  FIG. 9 , and forms a gasket seal to engage the upper rim of the bottle. Vent holes  228  extend through both the ring flange  822  and the overmolded TPE. Central membrane  814  has a molded durometer of about 50 shore A. Significantly harder inner members are believed to be less acceptable to infants, while significantly softer inner members may not return to their as-molded state quickly enough after being deformed inwardly during suckling. 
     The outer nipple members shown in the various drawings are also adapted to function as typical one-piece nipples without the inner members present. This means that the inner member can be removed as the baby is weaned from the breast and no longer needs the breast-like, peristaltic pumping response of the full, two-piece nipple assembly as described above. Versions of the outer member with larger outlet orifice sizes can also be provided for increased flow rates, for use as children grow and can tolerate higher flow rates. 
     Various modifications to the apparatus and techniques described herein are possible. For example, different materials may be used to fabricate particular nipples. Nipples may be adapted to mate with various bottle designs, with various securing device designs. Thickness of materials may be changed. The size of the inner member, relative to the size of the outer member may be changed. Various configurations of passages, holes, and flaps may be implemented. The connector can be implemented in various configurations. Alternate vent arrangements may be utilized. Additionally, the general shape and size of the nipple components can be modified. 
     Accordingly, other implementations are within the scope of the following claims.