Abstract:
The peristaltic teat is a cleanable teat which rewards the baby for making the same natural peristaltic tongue movement it makes at the mother&#39;s breast. The reward is that the baby gets (more) milk when making the correct movement. The consequence is that the baby will use the same drinking mechanism as at the breast. Hence bottle feeding will become closer to breast feeding which makes the combination of bottle feeding and breast feeding easier.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a teat for a baby feeding bottle, and more particularly to a teat that is configured to encourage a baby to use a natural breast-feeding action. 
       BACKGROUND OF THE INVENTION 
       [0002]    Many different designs of teats for baby feeding bottles are known. However, a disadvantage of known teats is that their configuration requires the baby to use a different drinking technique than that required when feeding from the mother&#39;s breast, since known teats do not provide milk flow in the same way as a mother&#39;s breast does. More specifically, when a baby feeds from its mother&#39;s breast, the baby applies the following actions: 
         [0003]    1. Sucking—to form a teat from the nipple, areola and underlying breast tissue. The negative pressure rewards the baby with a little milk. 
         [0004]    2. Peristaltic movement—the baby performs a peristaltic stripping movement with its tongue along the teat towards its mouth. The major part of the milk flow is caused by this movement. 
         [0005]    The combination of the above two actions stimulates the hormone production of the mother needed for the ‘let down reflex’ which causes the milk glands in the breast to release milk into the milk ducts. In this way, the initial sucking causes the let down reflex and thus doesn&#39;t immediately provide the baby with milk. Only after 4 or 5 feeding movements does the baby receive milk. 
         [0006]      FIG. 1  illustrates the natural peristaltic breast feeding action: in diagram ‘a’, a teat is formed between the baby&#39;s tongue and palate. At the base of the teat, a seal is formed by the lips and tongue. In diagram ‘b’, the lower jaw is raised, compressing the teat against the baby&#39;s upper jaw and trapping a pool of milk inside the nipple. In diagram ‘c’, a compression wave moves along the teat in a posterior direction, while the posterior part of the tongue forms a groove, channeling the milk into the back of the mouth. In diagram ‘d’, the compression wave squeezes milk from the nipple. In diagram ‘e’, as the tongue pushes against the palate and milk is collected, the baby usually swallows. In diagram ‘f’, depression of the back of the tongue draws the nipple once again inside the mouth, while the jaw lowers allowing milk to flow from the breast into the nipple. The cycle then repeats from diagram ‘a’ again. 
         [0007]    When a baby is fed from a bottle having an artificial teat, due to the construction of known bottle feeding teats, the feeding action that the baby is required to use is different to that which the baby must use when feeding from its mother&#39;s breast and the baby is only rewarded with milk for applying a negative pressure to the artificial teat (i.e. sucking), but not for using the natural peristaltic tongue action described above. This can lead to a condition in the baby known as ‘nipple confusion’, whereby the baby is unable to determine a correct feeding action to use when being fed from a bottle and from its mother&#39;s breast, and the baby unlearns the peristaltic feeding action and hence its natural breast-feeding skills. Accordingly, feeding problems occur interchanging between breast-feeding and bottle feeding. 
         [0008]    Known teats for bottle feeding are disclosed in EPO496892, U.S. Pat. No. 4,993,568 and US 2004/0245203. However, these teats are configured to encourage a baby to adopt a chewing action to obtain milk from the bottle, and therefore do not encourage a baby to adopt the same peristaltic feeding action as used when feeding at the mother&#39;s breast. Furthermore, the construction of each teat is such that a baby would still be able to obtain a sufficient flow of milk from the teat simply by using sucking action alone. 
         [0009]    US 2003/0089676, JP2001009008 and WO 2007/137440 all disclose teats on which a peristaltic feeding action can be performed by the baby in order to obtain milk from the feeding bottle. The teat disclosed in US2003/0089676 merely facilitates this action by attempting to recreate a similar elasticity to a natural mother&#39;s teat, and JP2001009008 merely facilitates this action by providing a teat which is able to elongate. WO 2007/137440 discusses a peristaltic action, however such an action is used to impart a vacuum, which can be obtained simply by using sucking action alone. Therefore, none of the teats encourages the baby to use the correct peristaltic feeding action by rewarding the baby for doing so and delivering less milk if such an action is not used. Each teat design merely facilitates use of a peristaltic feeding action. 
         [0010]    Known teats are also disclosed in US2004/0124168 and U.S. Pat. No. 6,818,162. Both of these documents disclose teats for baby feeding bottles which comprise one or more small tubes formed within a solid teat. The solid construction of these teats makes closure of the tubes difficult to achieve a peristaltic feeding action, and also the small tubes means that the teat is difficult to clean. 
       SUMMARY OF THE INVENTION 
       [0011]    It is an object of the present invention to provide a teat for a baby feeding bottle which substantially alleviates or overcomes the problems mentioned above. 
         [0012]    Accordingly, the present invention provides a teat for use with a feeding bottle having a mouthpiece on which a baby sucks during feeding extending from the main body with one or more apertures therein for the flow of milk out of the teat, a main body from which the mouthpiece extends, and an inner core disposed within the mouthpiece to define a fluid duct between the mouthpiece and the inner core, the mouthpiece and the inner core being configured such that during feeding, the mouthpiece and/or the inner core deform so as to make a peristaltic action possible which causes milk to flow along said duct and through said aperture. 
         [0013]    In a preferred embodiment, the inner core within the mouthpiece defines a plurality of separate ducts for the flow of milk along the ducts and out through the one or more apertures. 
         [0014]    Preferably, the teat includes a main body from which the mouthpiece extends, and the inner core extends from the mouthpiece into the main body. 
         [0015]    Preferably, the teat comprises at least one valve means within the mouthpiece which divides the or each duct into discrete sections and which is operable to allow milk to flow in one direction out of the teat but closes to resist the flow of milk in the opposite direction. 
         [0016]    Preferably, the valve means comprises at least one flexible flange extending between the mouthpiece and the inner core which divides the or each duct into discrete sections and which is moveable to allow milk to flow in one direction out of the teat but closes to resist the flow of milk in the opposite direction. 
         [0017]    The teat preferably comprises a plurality of flexible flanges. 
         [0018]    The or each flange is preferably secured to the mouthpiece is biased against the inner core, and the or each flange is preferably formed integrally with the mouthpiece. 
         [0019]    Alternatively, the or each flange may be secured to the inner core and is biased against the mouthpiece, and the or each flange may be formed integrally with the inner core. 
         [0020]    In a preferred embodiment, the inner core includes an absorbent outer surface, and the absorbent outer surface of the inner core may be made from foam. 
         [0021]    The inner core may comprise a sealed flexible tube filled with incompressible material, and the incompressible material is preferably a fluid. The incompressible material may be silicone gel, and the tube may be made from a stretchable material. 
         [0022]    The tube has may have a corrugated surface with the corrugations extending in a longitudinal direction of the mouthpiece. 
         [0023]    In another preferred embodiment, the mouthpiece includes elongate channels along its length which comprise said duct(s) and the inner core is flexible and includes longitudinal ribs extending into said channels, such that compression of the inner core causes the longitudinal ribs to extend further into the channels to close the channels and thereby close the duct(s). 
         [0024]    In another preferred embodiment, the inner core comprises an elongate recess along its length to define the or each duct between the mouthpiece and the inner core within the recess. 
         [0025]    Preferably, the inner core is removable from the mouthpiece. Conveniently, the teat can be inverted to aid cleaning of the teat and/or to facilitate removal of the inner core. 
         [0026]    In a preferred embodiment, the inner core is more rigid than the mouthpiece. 
         [0027]    Preferably, a perimeter surface of the inner core lies against the mouthpiece and a face is formed in the inner core, spaced from the mouthpiece, the duct being defined between said face and the mouthpiece. 
         [0028]    Advantageously, the inner core is integrally formed with the mouthpiece. 
         [0029]    In one embodiment, an end of the inner core, distal to the main body, is integrally formed with the mouthpiece. 
         [0030]    Conveniently, a support frame extends from the inner core through the main body and which, during use, locates against the main body and/or a bottle to support the inner core. 
         [0031]    The inner core may include a hollow bore extending longitudinally there through for the additional flow of milk. 
         [0032]    The present invention also provides a baby feeding bottle including a teat as described above. Conveniently, the baby feeding bottle includes a pressure release valve to equalize negative pressure within the bottle during feeding. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    Preferred embodiments of the present invention will now be described, by way of example only, with reference to  FIGS. 2-8D  of the accompanying drawings, in which: 
           [0034]      FIG. 1  illustrates a peristaltic feeding action of a baby; 
           [0035]      FIG. 2  shows a cross-sectional perspective view of a teat according to the present invention; 
           [0036]      FIG. 3  shows a schematic cross-sectional view along the line X-X of the mouthpiece portion of the teat of  FIG. 2 ; 
           [0037]      FIG. 4  shows an equivalent schematic cross-sectional view to that of  FIG. 3  but of a mouthpiece portion of a second embodiment of the present invention; 
           [0038]      FIG. 5A  shows an equivalent schematic cross-sectional view to that of  FIG. 3  but of a mouthpiece portion of a third embodiment of the present invention; 
           [0039]      FIGS. 5B and 5C  show schematic transverse cross-sectional views along the lines Z-Z and Y-Y of  FIG. 5A  respectively; 
           [0040]      FIG. 6A  shows an equivalent schematic cross-sectional view to that of  FIG. 3  but of a mouthpiece portion of a fourth embodiment of the present invention; 
           [0041]      FIGS. 6B and 6C  show schematic transverse cross-sectional views along the lines B-B and A-A of  FIG. 6A  respectively 
           [0042]      FIG. 7  shows an equivalent schematic cross-sectional view to that of  FIG. 3  but of a mouthpiece portion of a fifth embodiment of the present invention; 
           [0043]      FIG. 8A  shows a perspective view of a mouthpiece portion of a sixth embodiment of the present invention; 
           [0044]      FIG. 8B  shows a schematic longitudinal cross-sectional view along the line C-C of the mouthpiece portion of the teat of  FIG. 8A ; 
           [0045]      FIGS. 8C and 8D  show schematic transverse cross-sectional views along the lines D-D and E-E respectively in  FIG. 8B . 
           [0046]      FIG. 9A  shows a schematic cross-sectional view of a teat of a seventh embodiment of the present invention; 
           [0047]      FIG. 9B  shows a schematic transverse cross-sectional view along the lines F-F of  FIG. 9A ; 
           [0048]      FIG. 10A  shows a schematic cross-sectional view of a teat of an eighth embodiment of the present invention; 
           [0049]      FIG. 10B  shows a schematic transverse cross-sectional view along the lines G-G of  FIG. 10A ; 
           [0050]      FIG. 10C  shows a schematic cross-sectional view of the teat shown in  FIG. 10A  with an inner core drawn from a hollow outer membrane to facilitate cleaning of the teat; and 
           [0051]      FIG. 10D  shows a schematic transverse cross-sectional view along the lines H-H of  FIG. 10C . 
           [0052]      FIG. 11A  shows a schematic cross-sectional view of a teat of a ninth embodiment of the present invention; 
           [0053]      FIG. 11B  shows a schematic transverse cross-sectional view along the lines J-J of  FIG. 11A ; 
           [0054]      FIG. 11C  shows an exploded schematic cross-sectional view of the teat shown in  FIG. 11A ; 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0055]    Referring now to  FIGS. 2 and 3 , a teat  10  of a first embodiment of the present invention is shown comprising a hollow outer membrane  12  having a mouthpiece portion  14  and a main body portion  16 . An inner core  18  comprising a substantially cylindrical plug, is disposed within the mouthpiece  14  and extends slightly into the main body  16 . A duct  20  is thereby defined between the membrane  12  and the inner core  18  for the flow of milk, in use, from a feeding bottle (not shown) to which the teat  10  is to be attached, through the duct  20 , and into a baby&#39;s mouth through a plurality of apertures  22  formed in a distal end of the mouthpiece  14  remote from the main body  16 . The inner surface of the mouthpiece  14  is provided with a plurality of flanges  24  extending inwardly and around its circumference. The flanges  24  are curved towards the distal end of the mouthpiece  14  and bias against the inner core  18  such that the inner perimeter of each flange is in contact with and seals against the outer surface of the inner core  18 . This configuration is such that the duct  20  is divided into a plurality of ring-shaped chambers  20   a  and the flanges  24  act as one-way valves by permitting the flow of milk in a first direction from a feeding bottle towards the apertures  22  in the distal end of the mouthpiece  14 , but sealing against the inner core  18  to prevent the flow of milk in the opposite direction. 
         [0056]    Operation of the first embodiment of the present invention will now be described. In use, the teat  10  is attached to a feeding bottle in a known manner. The baby sucks on the mouthpiece  14  which is sufficient to cause a small flow of milk from the bottle into the duct  20 . The resilience of the flanges  24  is such that the sucking action of the baby and the resulting pressure difference between the baby&#39;s mouth and the inside of the bottle can cause a small amount of milk to flow along the duct  20  by deflecting the flanges  24  a small amount away from the inner core  18 . However, in order to obtain a full flow of milk from the bottle out of the teat  10 , a baby must use a peristaltic feeding action by which a wave of compression is exerted by the baby&#39;s tongue on the mouthpiece  14  as described above, in the direction of the distal end of the mouthpiece  14 . As each of the ring-shaped chambers  20   a  is compressed by the baby&#39;s tongue, the pressure in the chamber  20   a  increases and so the milk is forced into the adjacent chamber  20   a  in the direction of the distal end of the mouthpiece  14 . Due to the flanges  24  acting as one-way valves, the milk cannot flow into the adjacent chamber  20   a  in the opposite direction to the distal end of the mouthpiece  14 . After the milk has been forced into the adjacent ring-shaped chamber  20   a,  the peristaltic action of the baby&#39;s tongue then compresses said adjacent chamber  20   a  and forces the milk further through the duct  20  into the next chamber  20   a  and this action is repeated until the milk is at the distal end of the mouthpiece, where after it is expelled into the baby&#39;s mouth out of the apertures  22 . The baby then commences the peristaltic feeding action at the main body  16  end of the mouthpiece  14  again and the process is repeated to achieve continuous feeding. 
         [0057]    It will be appreciated that the teat  10  of the first embodiment of the invention is configured so that the above-described peristaltic feeding action provides the baby with the most amount of milk, compared to if the baby was to use a sucking or a chewing action. Accordingly, the baby is rewarded for using the same feeding action as with natural breast feeding, and so the problem of nipple confusion in switching between bottle feeding and breast feeding is prevented since the baby learns to use the same feeding action for both feeding methods. It should be noted that the stiffness of the flanges  24  can be chosen and manufactured to reward the sucking and peristaltic feeding action in any proportion. 
         [0058]    In order to facilitate cleaning of the above embodiment of the invention, the inner core  18  is removable from the mouthpiece  14  and membrane  12 . This is achievable by inverting the membrane (i.e. turning it inside out) and then the membrane  12  can be cleaned separately from the inner core  18 . However, in alternative embodiments of the present invention, the inner core  18  may not be removable from the mouthpiece  14 , yet the one-piece teat may still be capable of being inverted in order to facilitate cleaning with the inner core  18  remaining attached to the mouthpiece  14 . In both cases, the inner core  18  can aid the inverting of the teat. 
         [0059]    Un-illustrated variations in the above-described first embodiment are intended to fall within the scope of the claims hereafter, for example, the flanges  24  may be formed on the inner core  18  rather than on the inner surface of the mouthpiece  14  of the membrane  12 . Also, the sucking action of the child may also be rewarded by provided a continuous duct which extends through the length of the inner core  18 . 
         [0060]    Manufacture of the membrane  12  can be achieved by moulding it inside out, which is a known teat manufacturing technique. 
         [0061]    It will be appreciated that a peristaltic feeding action essentially comprises closing a duct/channel in which fluid is contained, and moving the closed position in the direction of the exit apertures to expel the fluid therefrom. In the above-described embodiment, the peristaltic feeding action of the baby is encouraged and rewarded by the milk duct  20  formed in the mouthpiece  14  being divided into a plurality of discrete chambers  20   a  and the peristaltic action, combined with the one-way valve action of the flanges  24 , resulting in the milk being progressively fed from one chamber  20   a  of the duct  20  to the next until it is expelled from the mouthpiece through the apertures  22 . However, alternative configurations of mouthpieces are intended to fall within the scope of the claims and the present invention which do not include such discrete chambers/valves, whereby milk is discharged from a bottle out of the mouthpiece using a continuous peristaltic action which closes a duct formed between the mouthpiece and inner core, and the point of closure of the duct moves along the mouthpiece towards the distal end thereof thereby forcing the milk out of the apertures in the distal end of the mouthpiece into the baby&#39;s mouth. A second embodiment of a teat  30  of the present invention which operates according to this latter principle will now be described with reference to  FIG. 4 . The overall construction of the teat  30  is largely the same as that of the teat  10  first embodiment described above, and only the specific construction of the mouthpiece portion  34  differs, as described below. Accordingly,  FIG. 4  only shows a schematic cross-section of the mouthpiece  34  of the teat  30  of the second embodiment. The teat  30  includes an inner core  38  disposed within the mouthpiece  34  such that a duct  40  for the flow of milk is defined there between. A plurality of apertures (not shown) are formed in the distal end of the mouthpiece  34  as described above with reference to the first embodiment of the invention. However, the inner core  38  includes an absorbent foam outer surface  44 . 
         [0062]    Operation of the second embodiment of the present invention will now be described. In use, the teat  30  is attached to a feeding bottle in a known manner. The baby sucks on the mouthpiece  34  which is sufficient to cause a small flow of milk from the bottle into the duct  40 , some of which is absorbed by the foam surface  44 . The density of the foam surface  44  and the size of the duct  40  is such that the sucking action of the baby and the resulting pressure difference between the baby&#39;s mouth and the inside of the bottle can cause only a small amount of milk to flow along the duct  40 . However, in order to obtain a full flow of milk from the bottle out of the teat  30 , a baby must use a peristaltic feeding action as described above. At the point of compression of the mouthpiece  34 , shown by arrows P in  FIG. 4 , the inner surface of the mouthpiece  34  compresses the foam surface  44 , expelling the milk therefrom and closing the duct  40 . As the baby exerts a peristaltic feeding action on the mouthpiece  34 , the compression point P where the duct  40  is closed moves along the mouthpiece  34 , thereby pushing ahead of it the milk in the duct  40  and absorbed in the foam outer surface  44 , until the compression point P reaches the distal end of the mouthpiece  34  and the milk is expelled out of the apertures  42  into the baby&#39;s mouth. The reduction in pressure caused in the bottle by this action draws more milk into the duct  40  behind the compression point P. After the milk is expelled from the mouthpiece  34 , the baby then repeats the feeding action starting with a compression point P at the main body end of the mouthpiece  34  and draws the milk along the duct  40  and out of the mouthpiece  34  as described above. 
         [0063]    A third embodiment of a teat  50  of the present invention will now be described with reference to  FIGS. 5A-5C . As with  FIG. 4 , the overall construction of the teat  50  is largely the same as that of the teat  10  of the first embodiment described above, and only the specific construction of a mouthpiece portion  54  differs, as described below. Accordingly,  FIGS. 5A-5C  only show a schematic cross-section of the mouthpiece  54  of the teat  50  of the third embodiment.  FIG. 5A  shows a longitudinal cross-section along the length of the mouthpiece, and  FIGS. 5B and 5C  show transverse cross-sectional views along the lines Z-Z and Y-Y respectively of the mouthpiece  54  in un-deformed and deformed states, as described below. The teat  50  includes an inner core  58  disposed within the mouthpiece  54  such that a duct  60  for the flow of milk is defined there between. A plurality of apertures (not shown) are formed in the distal end of the mouthpiece  54  as described above with reference to the first embodiment of the invention. The inner core  58  comprises a sealed flexible and stretchable tube  64  filled with a non-compressible but deformable material  66 , for example, but not limited to, silicone gel. As can be seen from  FIG. 5B , when the mouthpiece  54  is not compressed, the duct  60  is open. However, when the mouthpiece  54  is compressed, as shown by arrows P in  FIG. 5A  and in  FIG. 5C , the inner core  58  is deformed. However, since the material  66  filling the tube  64  is incompressible, the inner core  58  deforms within the mouthpiece  54  and the incompressible material  66  exerts an internal pressure on the stretchable tube  64 , causing it to expand and thereby fill the inside of the mouthpiece  54 , closing the duct  60 . 
         [0064]    Operation of the third embodiment of the present invention will now be described. In use, the teat  50  is attached to a feeding bottle in a known manner. The baby sucks on the mouthpiece  54 , which is sufficient to cause a small flow of milk from the bottle into the duct  60 . The size of the mouthpiece  54 , the inner core  58  and the resulting duct  60  is such that the sucking action of the baby and the resulting pressure difference between the baby&#39;s mouth and the inside of the bottle can cause only a small amount of milk to flow along the duct  60 . However, in order to obtain a full flow of milk from the bottle out of the teat  50 , a baby must use a peristaltic feeding action as described above. At the point of compression of the mouthpiece  54 , shown by arrows P in  FIG. 5A , the inner surface of the mouthpiece  54  contacts the inner core  58  and causes the inner core  58  to deform and close the duct  60 , as described above. As the baby exerts a peristaltic feeding action on the mouthpiece  54 , the compression point P where the duct  60  is closed moves along the mouthpiece  54 , thereby pushing ahead of it the milk in the duct  60  until the compression point P reaches the distal end of the mouthpiece  54  and the milk is expelled out of the apertures into the baby&#39;s mouth. The reduction in pressure caused in the bottle by this action draws more milk into the duct  60  behind the compression point P. After the milk is expelled from the mouthpiece  54 , the baby then repeats the feeding action starting with a compression point P at the main body end of the mouthpiece  54  and draws the milk along the duct  60  and out of the mouthpiece  54  as described above. 
         [0065]    A teat  70  of a fourth embodiment of the present invention will now be described with reference to  FIGS. 6A-6C . The fourth embodiment is similar to the third embodiment, and comprises teat  70  having a mouthpiece  74  with an inner core  78  disposed within the mouthpiece  74  such that a duct  80  for the flow of milk is defined there between. A plurality of apertures (not shown) are formed in the distal end of the mouthpiece  74  as described above with reference to the first embodiment of the invention. The inner core  78  comprises a sealed flexible tube  84  filled with a non-compressible but deformable material  86 , for example, but not limited to, silicone gel. However, unlike the third embodiment, the tube  84  is formed in a corrugated or ribbed pattern. Therefore, the tube  84  does not need to be made from a stretchable material because when the mouthpiece  74 , and thereby the inner core  78 , is compressed, the incompressible material  86  exerts an internal pressure on the tube  84 , causing the corrugations in the tube  84  to flatten out and so the tube  84  expands within the mouthpiece  74  and closes the duct  80 . Aside from the above-mentioned difference, the fourth embodiment of the invention is identical to that of the third embodiment, and so operation thereof is as described above with reference to the third embodiment, and so will not be repeated here. 
         [0066]    A fifth embodiment of a teat  90  of the present invention will now be described with reference to  FIG. 7 . The overall construction of the teat  90  is largely the same as that of the teat  10  of the first embodiment described above, and only the specific construction of a mouthpiece portion  94  differs, as described below. Accordingly,  FIG. 7  only shows a schematic cross-section of the mouthpiece  94  of the teat  90  of the fifth embodiment. The teat  90  comprises a mouthpiece  94  which has a main central cavity  95   a  with two elongate channels  95   b  extending from each side of the main central cavity  95   a  and extending longitudinally along the length of the mouthpiece  94 . The teat  90  includes a flexible inner core  98  disposed within the central cavity  95   a.  The inner core includes side ribs  98   a  which extend into the elongate channels  95   b  such that ducts  100  for the flow of milk are defined there between. A plurality of apertures (not shown) are formed in the distal end of the mouthpiece  94  as described above with reference to the first embodiment of the invention. As can be seen from  FIG. 7 , when the mouthpiece  94  is not compressed, the ducts  100  are open. However, when the mouthpiece  94  is compressed, as shown by arrows P, the inner core  98  is deformed and due to the shape of the inner core  98 , the side ribs  98   a  are pushed in the direction of arrows A further into the elongate channels  95   b,  thereby closing the ducts  100 . 
         [0067]    Operation of the fifth embodiment of the present invention will now be described. In use, the teat  90  is attached to a feeding bottle in a known manner. The baby sucks on the mouthpiece  94 , which is sufficient to cause a small flow of milk from the bottle into the ducts  100 . The size of the inner core  98 , elongate channels  95   b  and side ribs  98   a,  and the resulting ducts  100  are such that the sucking action of the baby and the resulting pressure difference between the baby&#39;s mouth and the inside of the bottle can cause only a small amount of milk to flow along the ducts  100 . However, in order to obtain a full flow of milk from the bottle out of the teat  90 , a baby must use a peristaltic feeding action as described above. At the point of compression of the mouthpiece  94 , shown by arrows P in  FIG. 7 , the inner surface of the mouthpiece  94  contacts the inner core  98  and causes the inner core  98  to deform and close the ducts  100 , as described above. As the baby exerts a peristaltic feeding action on the mouthpiece  94 , the compression point P where the ducts  100  are closed moves along the mouthpiece  94 , thereby pushing ahead of it the milk in the ducts  100  until the compression point P reaches the distal end of the mouthpiece  94  and the milk is expelled out of the apertures into the baby&#39;s mouth. The reduction in pressure caused in the bottle by this action draws more milk into the ducts  100  behind the compression point P. After the milk is expelled from the mouthpiece  94 , the baby then repeats the feeding action starting with a compression point P at the main body end of the mouthpiece  94  and draws the milk along the ducts  100  and out of the mouthpiece  94  as described above. 
         [0068]    A sixth embodiment of a teat  110  of the present invention will now be described with reference to  FIGS. 8A-8D . The overall construction of the teat  110  is largely the same as that of the teat  10  of the first embodiment described above, and only the specific construction of a mouthpiece portion  114  differs, as described below. Accordingly,  FIGS. 8A-8D  only show schematic views of the mouthpiece  114  of the teat  110  of the sixth embodiment. The teat  110  comprises a mouthpiece  114  and an inner core  118  disposed within the mouthpiece  114 . The inner core  118  is shaped as a flattened circle in cross-section, as can be seen from  FIGS. 8A ,  8 C and  8 D, and has an elongate recess  115  formed longitudinally along its length on its upper and lower sides. The mouthpiece lies adjacent to and in contact with the inner core around the majority of its perimeter surface such that ducts  120  for the flow of milk are defined in the recesses between the mouthpiece  114  and the inner core  118 . A plurality of apertures  122  are formed in the distal end of the mouthpiece  114  as described above with reference to the first embodiment of the invention. As can be seen from  FIGS. 8B and 8C , when the mouthpiece  114  is not compressed, the ducts  120  are open. However, when the mouthpiece  114  is compressed, as shown in  FIGS. 8B and 8D , the mouthpiece  114  is deformed into contact with the inner core  118  thereby closing the ducts  120 . 
         [0069]    Operation of the sixth embodiment of the present invention will now be described. In use, the teat  110  is attached to a feeding bottle in a known manner. The baby sucks on the mouthpiece  114 , which is sufficient to cause a small flow of milk from the bottle into the ducts  120 . The size of the inner core  118 , the depth of the recesses  115  and the resulting ducts  120  are such that the sucking action of the baby and the resulting pressure difference between the baby&#39;s mouth and the inside of the bottle can cause only a small amount of milk to flow along the ducts  120 . However, in order to obtain a full flow of milk from the bottle out of the teat  110 , a baby must use a peristaltic feeding action as described above. At the point of compression of the mouthpiece  114 , shown in  FIGS. 8B and 8D , the inner surface of the mouthpiece  114  contacts the inner core  118  at the recesses  115  and closes the ducts  120 , as described above. As the baby exerts a peristaltic feeding action on the mouthpiece  114 , the compression points where the ducts  120  are closed move along the mouthpiece  114 , thereby pushing ahead of it the milk in the ducts  120  until the compression point reaches the distal end of the mouthpiece  114  and the milk is expelled out of the apertures  122  into the baby&#39;s mouth. The reduction in pressure caused in the bottle by this action draws more milk into the ducts  120  behind the compression point. After the milk is expelled from the mouthpiece  114 , the baby then repeats the feeding action starting with a compression point at the main body end of the mouthpiece  114  and draws the milk along the duct  120  and out of the mouthpiece  114  as described above. 
         [0070]    One advantage of the sixth embodiment of the invention is that the inner core  118  does not need to be deformable as with the third, fourth and fifth embodiments, and so it can be made of a simple solid material, such as, but not limited to, silicone. The shape of this sixth embodiment also has the advantage that the baby can easily deform the mouthpiece with its tongue so making feeding with the correct peristaltic feeding action easier. 
         [0071]    The sixth embodiment of the invention may also include one or more one-way valves, such as the flanges shown in the first embodiment, although such an alternative embodiment is not illustrated. This would have the added advantage that the first few feeding actions of the baby would be ‘non-nutritive’—i.e. would not result in milk flow out of the teat immediately. This would simulate the ‘let down reflex’ in breast feeding mentioned above, and thereby better simulate natural breast feeding. 
         [0072]    A seventh embodiment of a teat  130  of the present invention will now be described with reference to  FIGS. 9A and 9B . The overall construction of the teat  130  is largely the same as that of the teat  10  of the first embodiment and comprises a hollow outer membrane  132  having a mouthpiece  134  and a main body  136 . An inner core  138  is disposed within the mouthpiece  134  and extends slightly into the main body  136 . The inner core  138  is integrally formed with the mouthpiece  134  and has an elongate arced face  140  that extends along the length of the inner core  138 . The arced face  140 , together with the inner surface of the mouthpiece  134 , defines a duct  142  for the flow of milk, in use, from a feeding bottle (not shown) to which the teat  130  is to be attached, through the duct  142 , and into a baby&#39;s mouth through an aperture  144  formed in a distal end of the mouthpiece  134  remote from the main body  136 . Although only one aperture is shown in the exemplary drawing, it will be understood that a plurality of apertures (not shown) may be formed in the distal end of the mouthpiece  134 . The membrane  132  and the inner core  138  are formed from a silicone material. As can be seen from  FIGS. 9A and 9B , when the mouthpiece  134  is not compressed, the duct  142  is open. The duct  142  is maintained in an open position due to the resilience of the membrane  132 . However, when the mouthpiece is compressed, as shown by arrow P, the duct  142  is closed by the mouthpiece  134  deforming and being urged into contact with the inner core  138 , closing the duct  142 . 
         [0073]    Operation of the seventh embodiment of the present invention will now be described. In use, the teat  130  is attached to a feeding bottle (not shown) in a known manner. The baby sucks on the mouthpiece  134 , which is sufficient to cause a small flow of milk from the bottle into the duct  142 . The size of the mouthpiece  134 , the inner core  138  and the resulting duct  142  is such that the sucking action of the baby and the resultant pressure difference between the baby&#39;s mouth and the inside of the bottle can cause only a small amount of milk to flow along the duct  134 . However, in order to obtain a full flow of milk from the bottle out of the teat  130 , a baby must use a peristaltic feeding action as described above. At the point of compression of the mouthpiece  134 , shown by arrow P in  FIG. 9A , the inner surface of the mouthpiece  134  contacts the arced face  140  of the inner core  138  and closes the duct  142 , as described above. As the baby exerts a peristaltic feeding action on the mouthpiece  134 , by which a compression wave is exerted by the baby&#39;s tongue on the mouthpiece  134  in the direction of the distal end of the mouthpiece  134 , the compression point, shown by arrow P, where the duct  142  is closed moves along the mouthpiece  134 , thereby pushing ahead of it the milk in the duct  142  until the compression point P reaches the distal end of the mouthpiece  134  and the milk is expelled out of the aperture  142  into the baby&#39;s mouth. The reduction in pressure caused in the bottle by this action draws more milk into the duct  142  behind the compression point P. After the milk is expelled from the mouthpiece  134 , the baby then repeats the feeding action starting with a compression point P at the main body end of the mouthpiece  134  and draws the milk along the duct  142  and out of the mouthpiece  134  as described above. 
         [0074]    One advantage of the seventh embodiment of the invention is that the arced face  139  of the inner core  138  is concave and so corresponds to the shape of a tongue. Furthermore, the mouthpiece at the compression point, shown by arrow P, can contact the arced face  140  and close the duct without the inner core  138  deforming. However, the invention is not limited thereto and the inner core  138  may deform at the compression point to provide an improved seal between the inner core  138  and the membrane  132 . 
         [0075]    An eighth embodiment of a teat  150  of the present invention will now be described with reference to  FIGS. 10A to 10D . The overall construction of the teat  150  is largely the same as the teat  130  of the seventh embodiment described above, and only the specific construction of the mouthpiece portion and inner core differs, as described below. The teat  150  comprises a hollow outer membrane  152  having a mouthpiece  154  and a main body  156 . An inner core  158  is disposed within the mouthpiece  154  and extends slightly into the main body  156 . A support frame  160  extends from an end of the inner core  158  located proximal to the main body  156  and extends through the main body  156 . The support frame  160  comprises a support rod  162  extending from the inner core  158 , a circumferentially extending rim  164  and spars  166  (refer to  FIG. 10D ) extending from the support rod  162  to the rim  164 . The rim  164  and the spars  166  define open apertures through which, in use, milk can flow from a feeding bottle (not shown) to which the teat is to be attached into the teat  150 . A section of the inner core  158  conforms to the contours of an inner surface of the mouthpiece  154  and the mouthpiece  154  lies adjacent to and in contact with the inner core  158  around the majority of its perimeter surface. However, the inner core  158  has an elongate arced face  168  formed longitudinally along its length, spaced from the inner surface of the mouthpiece  154 , which together with the inner surface of the mouthpiece  154 , defines a duct  170  for the flow of milk, in use, from a feeding bottle (not shown) to which the teat  150  is to be attached, through the duct  170 , and into a baby&#39;s mouth through an aperture (not shown) formed in a distal end of the mouthpiece  154  remote from the main body  156 . Although only one aperture is shown in the exemplary drawing, it will be understood that a plurality of apertures (not shown) may be formed in the distal end of the mouthpiece  154 . The inner core  158  is fixedly mounted to the mouthpiece  154  at the distal end of the mouthpiece remote from the main body  156 . In this exemplary embodiment the inner core  158  and mouthpiece  154  are integrally formed at the distal end. As can be seen from  FIG. 10B , when the mouthpiece  154  is not compressed, the arced face  168  is spaced from the membrane of the mouthpiece and the duct  170  is open. However, when the mouthpiece is compressed, as shown by arrow P, the duct is closed by the mouthpiece  154  deforming and being urged into contact with the arced face  168  of the inner core  158 , closing the duct  170 . 
         [0076]    Operation of the eighth embodiment of the present invention will now be described. In use, the teat  150  is attached to a feeding bottle (not shown) in a known manner. The circumferentially extending rim  164  of the support frame  160  locates against the feeding bottle to fixedly mount the support rod  162  and provide support for the inner core  158 . The baby sucks on the mouthpiece  154 , which is sufficient to cause a small flow of milk from the bottle into the duct  170 . The size of the mouthpiece  154 , the inner core  158  and the resulting duct  170  is such that the sucking action of the baby and the resultant pressure difference between the baby&#39;s mouth and the inside of the bottle can cause only a small amount of milk to flow along the duct  170 . However, in order to obtain a full flow of milk from the bottle out of the teat  150 , a baby must use a peristaltic feeding action as described above. At the point of compression of the mouthpiece  154 , shown by arrow P in  FIG. 10 , the inner surface of the mouthpiece  154  contacts the arced face  168  of inner core  138  and closes the duct  170 , as described above. As the baby exerts a peristaltic feeding action on the mouthpiece  154 , by which a compression wave is exerted by the baby&#39;s tongue on the mouthpiece  154  in the direction of the distal end of the mouthpiece  154 , the compression point P where the duct  170  is closed moves along the mouthpiece  154 , thereby pushing ahead of it the milk in the duct  170  until the compression point, shown by arrow P, reaches the distal end of the mouthpiece  154  and the milk is expelled out of the aperture (not shown) into the baby&#39;s mouth. The reduction in pressure caused in the bottle by this action draws more milk into the duct  170  behind the compression point P. After the milk is expelled from the mouthpiece  154 , the baby then repeats the feeding action starting with a compression point P at the main body end of the mouthpiece  154  and draws the milk along the duct  170  and out of the mouthpiece  154  as described above. 
         [0077]    In order to facilitate cleaning of the above embodiment of the invention, the inner core  158  is fixedly mounted at the end of the mouthpiece  154  distal to the main body  156 , however the membrane  152  of the one-piece teat  150  is capable of being inverted (i.e. turned inside out) in order to facilitate cleaning with the inner core  158  remaining attached to the mouthpiece  154 , but being easily accessible (refer to  FIG. 10C ). The inner core  158  can be used to aid the inverting of the membrane  152 , and the membrane can be easily flipped back over the inner core  158  after cleaning to reduce finger contact. 
         [0078]    Manufacture of the teat  150  of the eighth embodiment can be achieved by moulding it inside out, which is a known teat manufacturing technique. The arrangement of this embodiment allows a simple manufacturing technique. The membrane  152  and inner core  156  are manufactured from a silicone material. 
         [0079]    However, alternative configurations of teats similar to the seventh and eighth embodiments are intended to fall within the scope of the claims and the present invention, whereby the inner core is not integrally formed with the mouthpiece and an ninth embodiment of a teat  180  of the present invention will now be described with reference to  FIGS. 11A to 11C . The overall construction of the teat  180  is largely the same as that of the first embodiment described above, and the teat  180  comprises a hollow outer membrane  182  having a mouthpiece  184  and a main body portion  186 . An inner core  188  is disposed within the mouthpiece  184  and extends slightly into the main body  186 . A support frame  190  extends from an end of the inner core  188  located proximal to the main body  186  and extends through the main body  186 . The support frame  190  comprises a support rod  192  extending from the inner core  188 , a circumferentially extending rim  194  and spars (not shown) extending from the support rod  192  to the rim  194 . The rim  194  and the spars define open apertures through which, in use, milk can flow from a feeding bottle (not shown) to which the teat is to be attached into the main body  186  and the mouthpiece  184 . 
         [0080]    The inner core  188  has an elongate arced face  198  formed longitudinally along its length on its lower side. A section of the inner core  188  conforms to the contours of an inner surface of the mouthpiece  184  and the mouthpiece  184  lies adjacent to and in contact with the inner core  188  around the majority of its perimeter surface. However, the arced face  198  is spaced from the inner surface of the mouthpiece  184 , which together with the inner surface of the mouthpiece  184 , defines a duct  200  for the flow of milk, in use, from a feeding bottle (not shown) to which the teat  180  is to be attached, through the duct  200 , and into a baby&#39;s mouth through an aperture  202  formed in a distal end of the mouthpiece  184  remote from the main body  186 . Although only one aperture is shown in the exemplary drawing, it will be understood that a plurality of apertures (not shown) may be formed in the distal end of the mouthpiece  184 . The inner core  188  is formed separate to the mouthpiece  184  and is insertable and removable therefrom. As can be seen from  FIG. 11 , when the mouthpiece  184  is not compressed, the arced face  198  is spaced from the membrane of the mouthpiece and the duct  200  is open. However, when the mouthpiece is compressed, as shown by arrow P, the duct is closed by the mouthpiece  184  deforming and being urged into contact with the arced face  198  of the inner core  188 , closing the duct  200 . 
         [0081]    Operation of the ninth embodiment of the present invention will now be described. In use, the inner core  188  is inserting into the membrane  182  and disposed in the mouthpiece  174 . The inner core  188  locates against an inner surface thereof such that the inner surface and the arced face define the duct  200 . The teat  180  is attached to a feeding bottle (not shown) in a known manner. The circumferentially extending rim  194  of the support frame  190  locates against the feeding bottle to fixedly mount the support rod  192  and provide support for the inner core  188 . The baby sucks on the mouthpiece  184 , which is sufficient to cause a small flow of milk from the bottle into the duct  200 . The size of the mouthpiece  184 , the inner core  188  and the resulting duct  200  is such that the sucking action of the baby and the resultant pressure difference between the baby&#39;s mouth and the inside of the bottle can cause only a small amount of milk to flow along the duct  200 . However, in order to obtain a full flow of milk from the bottle out of the teat  180 , a baby must use a peristaltic feeding action as described above. At the point of compression of the mouthpiece  184 , shown by arrow P in  FIG. 11 , the inner surface of the mouthpiece  184  contacts the arced face  198  of inner core  188  and closes the duct  200 , as described above. As the baby exerts a peristaltic feeding action on the mouthpiece  184 , by which a compression wave is exerted by the baby&#39;s tongue on the mouthpiece  184  in the direction of the distal end of the mouthpiece  184 , the compression point P where the duct  200  is closed moves along the mouthpiece  184 , thereby pushing ahead of it the milk in the duct  200  until the compression point, shown by arrow P, reaches the distal end of the mouthpiece  184  and the milk is expelled out of the aperture  202  into the baby&#39;s mouth. The reduction in pressure caused in the bottle by this action draws more milk into the duct  200  behind the compression point P. After the milk is expelled from the mouthpiece  184 , the baby then repeats the feeding action starting with a compression point P at the main body end of the mouthpiece  184  and draws the milk along the duct  200  and out of the mouthpiece  184  as described above. 
         [0082]    Manufacture of the teat  180  of the ninth embodiment can be achieved by moulding the inner core  188  and the membrane  182  as separate components. The two individual components are then assembled before use. An advantage of the present embodiment is that it simplifies manufacture of each component. In the present exemplary embodiment the inner core  182  is formed from a thermoplastic, but the invention is not limited thereto and the inner core can be formed from a silicone, 2K part or any suitable material. The membrane  182  is formed from a silicone 30 shore material, although the invention is not limited thereto. 
         [0083]    One advantage of the ninth embodiment of the invention is that the inner core  188  does not need to be deformable as with the seventh and eighth embodiments, and so it can be made of a simple solid material, such as, but not limited to, a thermoplastic. 
         [0084]    In order to facilitate cleaning of the above embodiment of the invention, the inner core  188  is removable from the mouthpiece  184 . This is achievable by inverting the membrane  182  and then the membrane  182  can be cleaned separately from the inner core  18 . Furthermore, another advantage of this embodiment is that when the inner core  188  is removed, the hollow outer membrane  182  can be used as a conventional teat without the inner core  188  being present. 
         [0085]    The ninth embodiment of the invention may also include one or more one-way valves, such as the flanges shown in the first embodiment, although such an alternative embodiment is not illustrated. This would have the added advantage that the first few feeding actions of the baby would be ‘non-nutritive’—i.e. would not result in milk flow out of the teat immediately. This would simulate the ‘let down reflex’ in breast feeding mentioned above, and thereby better simulate natural breast feeding. 
         [0086]    It will be appreciated that the teats  130 , 150 , 170  of the seventh to ninth embodiments of the invention are configured so that the above-described peristaltic feeding action provides the baby with the most amount of milk, compared to if the baby was to use a sucking or chewing action. Accordingly, the baby is rewarded for using the same feeding action as with natural breast feeding, and so the problem of nipple confusion in switching between bottle feeding and breast feeding is prevented since the baby learns to use the same feeding action for both feeding methods. It should be noted that the wall thickness and stiffness of the membrane can be chosen and manufactured to control the flexibility of the teat and reward the sucking and peristaltic feeding action in any proportion. 
         [0087]    All of the above embodiments of the present invention reward a baby during bottle feeding for using the natural peristaltic feeding action by delivery of the largest flow of milk compared to that which would be delivered if the baby only used a sucking action. Therefore, the baby is encouraged to use the same feeding technique when bottle feeding as when breast feeding, and so does not ‘un-learn’ the natural breast feeding action, making it easier to interchange between bottle feeding and breast feeding, and avoiding nipple confusion in the baby. Furthermore, the construction of each embodiment is such that a peristaltic feeding action is easy for the baby to accomplish. 
         [0088]    In addition to the above, since the various embodiments of the teat of the invention encourage a baby to use the correct peristaltic feeding action, the teat can be used to teach a baby the correct breast feeding action if the baby has not instinctively developed such a skill itself, as can sometimes be the case. 
         [0089]    Further advantages of the teat of the invention is that since the mouthpiece of the teat includes an inner core, the core provides a degree of support to the mouthpiece, and so the membrane and mouthpiece can be manufactured without needing to consider resistance to collapsing, which is an important design criteria to be considered in the manufacture of conventional hollow teats which do not have a core disposed within the mouthpiece. 
         [0090]    Yet another advantage of the present invention is that peristaltic action, which the baby is encouraged to use, is capable of creating a significant pressure difference between the interior of the feeding bottle and ambient surroundings, much more than could be produced by the baby using a sucking action alone. Accordingly, a baby will be able to obtain milk from a feeding bottle using a teat of the present invention, even if the pressure in the bottle is lower than that of the ambient surroundings, to a much greater degree than would be possible using conventional teats. Therefore, in feeding bottles which incorporate a valve to equalize the negative pressure within a feeding bottle, a much larger tolerance on the opening pressure of the valve is possible, and so leakage from the bottle is easier to avoid. 
         [0091]    It will be appreciated that in embodiments shown and described above, the inner core of the teat is preferably removable from the mouthpiece portion to facilitate cleaning of the teat, although the embodiments of the invention are not limited to such a feature. In particular, in embodiments seven and eight the inner core is integrally formed with the mouthpiece so that the teat is manufactured as a single component which reduces the chance of incorrect assembly of the teat during use. 
         [0092]    In addition to the embodiments described above, it is intended for the following features, independently or in combination where appropriate, to fall within the scope of the invention: 
         [0093]    a) Teat may include a main body from which the mouthpiece extends, and the inner core extends from the mouthpiece into the main body; 
         [0094]    b) the teat may comprise a plurality of flexible flanges; 
         [0095]    c) the or each flange of the teat may be secured to the mouthpiece and is biased against the inner core; 
         [0096]    d) the or each flange of the teat may be formed integrally with the mouthpiece; 
         [0097]    e) the or each flange of the teat may be secured to the inner core and biased against the mouthpiece; 
         [0098]    f) the or each flange of the teat may be formed integrally with the inner core; 
         [0099]    g) the incompressible material in the flexible tube may be silicone gel; 
         [0100]    h) the teat may be inverted to aid cleaning of the teat and/or to facilitate removal of the inner core; 
         [0101]    i) the inner core may be more rigid than the mouthpiece; and 
         [0102]    j) a baby feeding bottle including a teat of the invention may include a pressure release valve to equalize negative pressure within the bottle during feeding. 
         [0103]    Although claims have been formulated in this application to particular combinations of features, it should be understood that the scope of the disclosure of the present invention also includes any novel features or any novel combination of features disclosed herein either explicitly or implicitly or any generalization thereof, whether or not it relates to the same invention as presently claimed in any claim and whether or not it mitigates any or all of the same technical problems as does the present invention. The applicants hereby give notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present application or of any further application derived therefrom.