TEAT FOR AN INFANT FEEDING BOTTLE

Abstract

A teat (10) for an infant feeding bottle (1), including a resilient wall (12) defining a central nipple (14a) and an areola (14b) that extend around a central axis (L), said teat being elastically transformable between a distended state in which the nipple defines a global maximum (38) and at least one depressed state that is accessible from the distended state by forcing the nipple at least partially into the areola along the central axis, and in which said wall (12) additionally defines an annular double fold (32) that defines an outer local maximum (34) and an inner local minimum (36), both extending circumferentially around the global maximum, wherein the wall defines a circumferential fold region (30) that, in said at least one depressed state, ranges from the local maximum to the local minimum of the double fold, and wherein said fold region has a rotationally asymmetric stiffness distribution.

Claims

1. A teat for an infant feeding bottle, the teat comprising: a nipple; an areola; and a resilient wall defining the nipple and the areola such that they extend around a central axis, said teat being elastically transformable between a distended state in which the nipple defines a global maximum and at least one depressed state that is accessible from the distended state by forcing the nipple at least partially into the areola along the central axis, wherein, in the depressed state, the resilient wall defines a fold region having an annular double fold that is absent in the distended state and defines an outer local maximum and an inner local minimum, both extending circumferentially around the global maximum, wherein, when the teat is transitioned from the distended state to the depressed state, the nipple extends above the outer local maximum and below the global maximum, and wherein, when the teat is transitioned from the distended state to the depressed state, the fold region has a rotationally asymmetric stiffness distribution for preventing a metastable depression of the nipple into the areola by effecting an elastic transformation of the resilient wall from the depressed state back to the distended state.

2. The teat of claim 1, wherein the resilient wall includes a plurality of elongate, tangentially equidistantly spaced-apart ribs that are arranged on an inner surface of the resilient wall; and wherein at least one of the ribs has at least one of a different length, a different width and a different thickness than the other ribs to provide the rotationally asymmetric wall thickness distribution in the fold region of the areola when the resilient wall is transitioned from the distended state to the depressed state.

3. The teat of claim 1, wherein, the fold region of the areola includes a rotationally asymmetric distribution of at least two materials having a mutually different modulus of elasticity to provide the rotationally asymmetric stiffness distribution in the fold region of the areola when the resilient wall is transitioned from the distended state to the depressed state.

4. The teat of claim 1, wherein the depressed state is a maximally depressed state of the resilient wall.

5. The teat of claim 1, wherein the nipple has a rotationally stiffness distribution for preventing a collapse of the nipple.

6. The teat of claim 1, wherein the nipple defines a head, the areola defines a shoulder, and at least one of the areola and the nipple defines a neck that connects the head to the shoulder, wherein the head has a maximum outer diameter D.sub.head,max, wherein the neck has a minimum outer diameter D.sub.neck,min, and wherein the shoulder has a minimum outer diameter D.sub.shoulder,min and a maximum outer diameter D.sub.shoulder,max, such that D.sub.shoulder,max>D.sub.shoulder,min>D.sub.head,max≥D.sub.neck,min.

7. The teat of claim 1, wherein the areola includes a circumferential arrangement of a plurality of substantially identical and equidistantly spaced apart recesses.

8. The teat of claim 1, wherein the rotationally asymmetric stiffness distribution in the fold region is: at least partially effected through a plurality of elongate, tangentially equidistantly spaced-apart ribs that are arranged on an inner surface of the resilient wall and defined by wall thickness-defined structures of said resilient wall, wherein at least one of the ribs has a different length, width, and/or thickness than the other ribs, such that said ribs effect a rotationally asymmetric wall thickness distribution in said fold region, or at least partially effected through the use of a rotationally asymmetric distribution of at least two materials having a mutually different modulus of elasticity.

9. The teat of claim 1, wherein a central axis of each fold of the double fold is at an acute angle relative to the central axis of the areola.

10. An infant feeding bottle, comprising: bottle body; and a teat attachable to the bottle body, wherein the teat comprises, a nipple, an areola, and a resilient wall defining the nipple and the areola such that they extend around a central axis, said teat being elastically transformable between a distended state in which the nipple defines a global maximum and at least one depressed state that is accessible from the distended state by forcing the nipple at least partially into the areola along the central axis, wherein, in the depressed state, the resilient wall defines a fold region having an annular double fold that is absent in the distended state and defines an outer local maximum and an inner local minimum, both extending circumferentially around the global maximum, wherein, when the teat is transitioned from the distended state to the depressed state, the nipple extends above the outer local maximum and below the global maximum, and wherein, when the teat is transitioned from the distended state to the depressed state, the fold region has a rotationally asymmetric stiffness distribution for preventing a metastable depression of the nipple into the areola by effecting an elastic transformation of the resilient wall from the depressed state back to the distended state.

11. The infant feeding bottle of claim 10, wherein the resilient wall includes a plurality of elongate, tangentially equidistantly spaced-apart ribs that are arranged on an inner surface of the resilient wall; and wherein at least one of the ribs has at least one of a different length, a different width and a different thickness than the other ribs to provide the rotationally asymmetric wall thickness distribution in the fold region of the areola when the resilient wall is transitioned from the distended state to the depressed state.

12. The infant feeding bottle of claim 10, wherein the fold region of the areola includes a rotationally asymmetric distribution of at least two materials having a mutually different modulus of elasticity to provide the rotationally asymmetric stiffness distribution in the fold region of the areola.

13. The infant feeding bottle of claim 10, wherein the depressed state is a maximally depressed state of the resilient wall.

14. The infant feeding bottle of claim 10, wherein the nipple has a rotationally stiffness distribution for preventing a collapse of the nipple.

15. The infant feeding bottle of claim 10, wherein the nipple defines a head, the areola defines a shoulder, and at least one of the areola and the nipple defines a neck that connects the head to the shoulder, wherein the head has a maximum outer diameter D.sub.head,max, wherein the neck has a minimum outer diameter D.sub.neck,min, and wherein the shoulder has a minimum outer diameter D.sub.shoulder,min and a maximum outer diameter D.sub.shoulder,max, such that D.sub.shoulder,max>D.sub.shoulder,min>D.sub.head,max≥D.sub.neck,min.

16. The infant feeding bottle of claim 10, wherein the areola includes a circumferential arrangement of a plurality of substantially identical and equidistantly spaced apart recesses.

17. The infant feeding bottle of claim 10, wherein the rotationally asymmetric stiffness distribution in the fold region is: at least partially effected through a plurality of elongate, tangentially equidistantly spaced-apart ribs that are arranged on an inner surface of the resilient wall and defined by wall thickness-defined structures of said resilient wall, wherein at least one of the ribs has a different length, width, and/or thickness than the other ribs, such that said ribs effect a rotationally asymmetric wall thickness distribution in said fold region, or at least partially effected through the use of a rotationally asymmetric distribution of at least two materials having a mutually different modulus of elasticity.

18. The infant feeding bottle of claim 10, wherein a central axis of each fold of the double fold is at an acute angle relative to the central axis of the areola.

19. A teat coupled to and for use with an infant feeding bottle, the infant feeding bottle comprising a bottle body for containing a liquid food item for an infant, the teat comprising: a nipple; an areola from which the nipple extends along a central axis of the areola, the areola comprising a plurality of ovoidal recesses circumferentially disposed around the central axis of the areola and on an inner surface of the areola; a resilient wall defining the nipple and the areola; and a plurality of ribs disposed along an inner surface of the resilient wall between the nipple and the areola to reinforce the teat, wherein the teat has a first position and a second position: the first position being a distended stable equilibrium state, where the nipple defines a global maximum, the second position being a depressed metastable equilibrium state, which forms an annular double fold along the resilient wall, such that the resilient wall defines an annular outer local maximum and an annular inner local minimum, wherein the annular double fold is absent in the first position, wherein the teat transitions from the first position to the second position by forcing the nipple at least partially into the areola along a path coincident with the central axis of the areola, wherein the nipple is forced at least partially into the areola as a result of an underpressure within an interior of the bottle body of the infant feeding bottle, wherein, in the second position, the areola and the nipple define an intermediate compressive state therebetween that forms a barrier to a free transition from the second position to the first position, wherein the outer local maximum and inner local minimum each extend circumferentially around the global maximum of the nipple, such that in the second position, the resilient wall defines a circumferential fold region positioned between the outer local maximum and the inner local minimum, wherein the teat comprises a maximum depression when the outer local maximum is substantially equal to the global maximum and when the circumferential fold region is largest, wherein, during the transition from the first position to the second position, the circumferential fold region is forced through a confined annular underlying area disposed in a plane transverse to the central axis and radially in between the outer local maximum and the inner local minimum of the annular double fold, such that an approximate diameter of the circumferential fold region in the first position is equal to the approximate diameter of the circumferential fold region in the second position, and wherein, in the second position, the circumferential fold region has a stiffness distribution that is rotationally asymmetric, such that the teat transitions from the second position to the first position via an asymmetric path.

20. The teat of claim 19, wherein the rotationally asymmetric stiffness distribution in the circumferential fold region is: at least partially effected through a plurality of elongate, tangentially equidistantly spaced-apart ribs that are arranged on an inner surface of the resilient wall and defined by wall thickness-defined structures of said resilient wall, wherein at least one of the ribs has a different length, width, and/or thickness than the other ribs, such that said ribs effect a rotationally asymmetric wall thickness distribution in said fold region, or at least partially effected through the use of a rotationally asymmetric distribution of at least two materials having a mutually different modulus of elasticity.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a schematic side view of an infant feeding bottle, including an exemplary embodiment of a teat according to the present invention;

[0019] FIG. 2A-D schematically show a perspective view, a side view, a bottom view and a bottom perspective view, respectively, of the isolated exemplary embodiment of the teat shown in FIG. 1;

[0020] FIG. 3A-B schematically show a longitudinal cross-sectional side view of the exemplary embodiment of the teat shown in FIGS. 1-2, wherein the teat is depicted in its distended state and a depressed state, respectively; and

[0021] FIG. 4 schematically illustrates how the teat of FIGS. 1-3 may elastically transform from its depressed state, schematically shown in FIG. 3B, back to its distended state, schematically shown in FIG. 3A.

[0022] FIG. 5 schematically illustrates various diameters of the teat shown in FIG. 2B.

[0023] FIG. 6A schematically illustrate a front view of a length and a width of a rib 40b shown in FIGS. 2C, 2D, 3A and 3B.

[0024] FIG. 6B schematically illustrate a front view of the length and a thickness of the rib 40b shown in FIGS. 2C, 2D, 3A and 3B.

[0025] FIG. 7A schematically illustrates a top view of a rotationally asymmetric stiffness distribution across 75% of a width of a fold region 30 shown in FIGS. 3A and 3B,

[0026] FIG. 7B schematically illustrates a top view of a rotationally asymmetric stiffness distribution across 90% of a width of a fold region 30 shown in FIGS. 3A and 3B.

DETAILED DESCRIPTION

[0027] FIG. 1 depicts a schematic side view of an exemplary infant feeding bottle 1. The bottle 1 may have a three-part design and include a bottle body 60, a screw ring 50, and a resilient teat 10. The substantially hollow bottle body 60, configured to contain a liquid infant food, may include an upper portion (invisible in FIG. 1) provided with an outer screw thread that is engageable by an inner screw thread provided on an inner wall of a passage through the screw ring 50, such that the screw ring 50 is screwingly attachable to the upper portion of the bottle body 60. The inner passage of the screw ring 50 may further define an upper, constricted opening with a circumferential rim or edge that is configured to sealingly engage a lower portion or skirt 22 of the teat 10 (see FIG. 2B). In case the teat 10, which will be described in more detail below, is properly inserted into the screw ring 50, and the screw ring 50 is in turn screwingly attached to the bottle body 60, the infant feeding bottle shown in FIG. 1 may be obtained. The bottle body 60 and the screw ring 50 may in themselves be of a conventional construction and will therefore not be elaborated upon here any further.

[0028] FIGS. 2A-D show the resilient teat 10 in isolation, respectively in a schematic perspective view, side view, bottom view and bottom perspective view. In addition, FIGS. 3A-B schematically show longitudinal cross-sectional side views of the teat 10, wherein the teat is respectively depicted in its distended state and in a depressed state. The construction of the teat 10 according to the present invention will now be discussed in general terms, where appropriate with reference to the exemplary embodiment illustrated in both FIGS. 2A-D and FIGS. 3A-B.

[0029] The anatomy of the teat 10 may include a skirt or base 22, an areola 14b, positioned on top of the skirt 22, and a nipple 14a that, at least in a distended state of the teat 10, may protrude substantially centrally from the areola 14b. An inner surface 12a of the teat wall 12 defining the nipple 14a and the areola 14b may define an interior food reception space 18, and the nipple 14a may define at least one food discharge opening 20. As is illustrated in FIG. 2B, the structure of the nipple 14a and areola 14b may be described in some more detail in terms of a head 16a, a neck 16b and a shoulder 16c. Accordingly, the nipple 14a may define the head 16a, while the areola 14b may define the shoulder 16c, and at least one of the nipple 14a and the areola 14b may define the neck 16b that connects the head 16a to the shoulder 16c.

[0030] The skirt 22 of the teat 10 may serve to connect it to the screw ring 50, shown in FIG. 1. To that end, the skirt may define an annular groove or recess 24 configured to receive a rim defining a top opening of a passage through the screw ring 50, and a clamp portion 26 configured to pressingly engage an inner wall of that passage so as to fluid tightly seal the connection between the teat 10 and the screw ring 50.

[0031] As regards the overall form of the teat 10 the following may be noted. The teat 10 may have a generally axisymmetric shape, at least on the outside. That is, an outer surface 12b of a resilient, deformable wall 12 defining the teat 10 may be axisymmetric (aside from optional, structurally irrelevant embossings), while the inner surface 12a of the wall 12 may or may not be. Furthermore, in the depicted embodiment, the neck 16b and shoulder 16c of the teat 10 are substantially outwardly concave. It is contemplated, however, that alternative embodiments of the teat 10 may include a substantially outwardly convex neck 16b and shoulder 16c, or a substantially outwardly concave neck 16b in combination with a substantially outwardly convex shoulder 16. To provide the teat 10 with an organic shape that is easy and friendly to latch on to for an infant during feeding, the neck 16b may preferably be substantially outwardly concave, such that it defines a slight constriction. More specifically, in a preferred embodiment the head 16a may have a maximum outer diameter D.sub.head,max, while the neck 16b may have a minimum outer diameter D.sub.neck,min, and the shoulder 16c may have a minimum outer diameter D.sub.shoulder,min and a maximum outer diameter D.sub.shoulder,max, such that D.sub.shoulder,max>D.sub.shoulder,min>D.sub.head,max≥D.sub.neck,min. such as, for example, as shown in FIG. 5 illustrating a maximum outer diameter 16d of head 16, a minimum outer diameter 16e of neck 16b, a minimum outer diameter 16f of shoulder 16c and a maximum outer diameter 16g of shoulder 16c.

[0032] In one embodiment, the areola 14b of the teat 10 may be softened, i.e. made less stiff and more pliable and thus softer to the touch, for instance by the provision of a plurality of recesses in the inner surface 12a of the wall 12, which recesses 28 may extend in a circumferential, it itself rotationally symmetrical arrangement around the longitudinal axis L of the teat 10. In the depicted embodiment, the recesses 28 are all identical, regularly spaced apart in the tangential direction, and ovoidally shaped. An inner face of the ovoidal recess 28 may each time be generally concave. It is understood, however, that softening of the areola 14b of the teat 10 may be accomplished through a variety of alternative means. One such alternative means may, for example, include a teat wall portion that defines a band of reduced wall thickness that extends tangentially around the longitudinal axis L of the teat 10, and describes a sinusoidal or otherwise wave-shaped path (highs and lows being spaced apart in the axial direction).

[0033] In another embodiment, the nipple 14a of the teat 10, and in particular the neck portion 16b thereof, may be reinforced to prevent it from collapsing during use. To this end, the surface 12a, 12b of the wall 12 in the neck region 16b may, for instance, be provided with a plurality of ribs. The ribs may typically extend along the neck 16b, either in a direction with a mere radial and/or axial component, or helically, in a direction that additionally includes a tangential component. The plurality of ribs may be provided in a circumferential, in itself rotationally symmetric arrangement, and the ribs may be mutually identical.

[0034] It is noted for clarity that the provision of such a rotationally symmetric arrangement of ribs in the neck 16b of a teat 10 is known in the art as a measure against collapse of the teat. In the depicted embodiment of the teat 10, however, the inner surface 12a of the teat wall 12 features a rotationally a-symmetric arrangement of ribs 40a, 40b, including two ‘thin’ ribs 40a and one ‘thick’ rib 40b, which extend not only in the neck 16b of the teat 10 but also in its shoulder 16c. The purpose of the arrangement of the ribs 40a, 40b is to prevent both collapse of the neck portion 16b of the nipple 14a, and metastable depression of the nipple 14a into the areola 14b.

[0035] For a fuller understanding of this latter function, to which the aforementioned asymmetry of the arrangement is important, attention is invited to in particular FIGS. 3A-B, which, as mentioned, schematically show longitudinal cross-sectional side views of the teat 10, wherein the teat is respectively depicted in its distended state and in a depressed state.

[0036] A transition of the teat 10 from its distended state into a depressed state, which may be effected by forced downwards movement of the nipple 14a into the areola 14b along the central axis L, e.g. as a result of underpressure within the interior food reception space 18, may give rise to the formation of an annular double fold or annular S-fold 32 in the teat wall 12. The double annular fold 32 may normally be absent in the distended state, and define an outer local maximum or hill 34 and an inner local minimum or well 36. Both the local maximum 34 and local minimum 36 may be annular and extend around a global maximum 38 defined by the nipple 14a of the teat 10. The portion of the teat wall 12 that, in a certain depressed state, defines the annular double fold 32 may be designated as the fold region 30 associated with that state. In a depressed state, the fold region 30 may range from the local maximum 34 to the local minimum 36 of the double fold 32, with the understanding the fold region 30 includes these local extrema 34, 36. The extrema 34, 36 may typically correspond to points of (local) maximum curvature, and thus to points of maximum deformation and elastic stress.

[0037] In general, a teat 10 may have multiple depressed states, each of which may be characterized by a fold region 30 of a certain width. This width may be measured in a radial/axial direction along the teat wall 12. Depressed states in which the nipple 14b is depressed further into the areola 14b may normally have a larger local maximum-to-local minimum distance, and hence a deeper fold 32 and a wider fold region 30. Because the fold region 30 may thus grow in width upon further depression of the nipple 14a, it may be preferable to define the fold region 30 with respect to a maximally depressed state, in which the nipple 14a is forced down into the areola 14b up to the point that the global maximum 38 it defines equals the local maximum 34 defined by the double fold 32. In such an embodiment, the fold region 30 may cover all fold regions associated with lesser depressed states.

[0038] During a transition of the teat 10 from the distended state to a depressed state, the relatively large area of the fold region 30 may be forcefully pressed through a confined annular underlying area, disposed in a plane transverse to the central axis L of the teat 10 and radially in between the later local maximum 34 and local minimum 36 of the double fold 32. The deformation of the fold region 30 may thus entail temporary displacement of wall material towards the central axis L of the teat 10, which may result in a compressive stress in the teat wall 12 in the tangential direction. Upon passing the annular underlying area, however, the stress in the teat wall 12 may be released, and the material in the fold region 30 may return to its approximate original diameter (i.e. its diameter in the distended state), beit at a different, lower axial position.

[0039] Although the distended state, in which the teat wall 12 is substantially relaxed, may represent an elastic-energy minimum that is lower than that of the depressed state, in which the teat wall 12 is partly deformed, the compressive state in between them may form a barrier to free transition. Accordingly, the distended state may be characterized as a stable equilibrium of the teat 10, while the depressed state may be characterized as a metastable equilibrium that is separated from the stable equilibrium by the intermediate compressive state. The metastability of the depressed state may in particular be present in conventional teat having a softened areola and a generally axisymmetric shape. This is because the elastic stresses in the fold region of the teat wall in such a teat may, on the one hand, be relatively small, and, on the other hand, be symmetrically distributed around the central axis. The symmetry may effectively raise the barrier defined by the compressive state (since the elastic deformation stresses counteract each other in attempts of the teat wall to relax), and leave elastic stresses in the wall incapable to effect the transition from the depressed state back to the distended state, thus fostering the metastability of the former.

[0040] The teat according to the present invention overcomes the problem of metastability of the depressed state by introducing a rotationally asymmetric stiffness distribution in the fold region 30 of the teat wall 12, optionally without affecting either the general axisymmetric shape of the teat 10, or the sometimes desired softening of its areola 14b. The rotationally asymmetric stiffness distribution in the fold region 30 of the teat wall 12 ensures that, in an associated depressed state, an asymmetry exists in the elastic stresses that are present in the deformed wall 12. Fold region portions with a higher stiffness will exert greater (and thus partly unbalanced) restoring forces than fold region portions with a smaller stiffness, and thus force the nipple 14a out of the areola 14b through an asymmetrical transition path, which will be clarified below with reference to FIG. 4.

[0041] The rotationally asymmetric stiffness distribution of the teat wall 12 in the fold region 30 may be effected in different ways.

[0042] In one embodiment, the rotationally asymmetric stiffness distribution in the fold region 30 may be at least partially effected through a rotationally asymmetric wall thickness distribution in said region. For example, one (longitudinal) half of the teat wall 12 may have a thickness that is slightly different from that of the other (longitudinal) half of the teat wall 12. Alternatively, the fold region 30 may, for instance, include a rotationally asymmetric arrangement of wall thickness-defined structures, e.g. protrusions or recesses, either at the outer surface 12b of the teat wall 12, the inner surface 12a of the teat wall 12, or at both surfaces 12a, 12b. Wall-thickness defined structures at the inner surface 12a of the teat wall 12 may be preferred, as they may be of no consequence to the tactile and/or visual perception of the teat 10 during use. In principle, wall-thickness defined structures may have any suitable placement, shape, or size. In a preferred embodiment, a structure may disposed such that it extends across at least one of the local maximum 34 and the local minimum 36 of the annular double fold 32 when the teat 10 is in a depressed state. In such an embodiment the structure may be deployed very effectively since it may cover at least one of the points of maximum curvature and elastic stress. In another embodiment, a structure may be disposed such that it extends across substantially an entire width of a fold region 30, e.g., across at least 75% of the width of the fold region 30 as exemplary shown in FIG. 7A illustrating a structure 31 extending across 75% of the width of the fold region 30. More preferably across at least 90% thereof as exemplary shown in FIG. 7B illustrating a structure 32 extending across 90% of the width of the fold region 30, wherein the width may be measured in a radial/axial direction along the teat wall 12. Accordingly, it may prevent metastable retraction of the nipple 14a for the depressed state associated with that fold region 30, and any lesser depressed state.

[0043] In a preferred embodiment of the teat 10, such as the one depicted in FIGS. 1-3, the wall-thickness defined structure may take the form of an elongate rib 40b. In the illustrated embodiment, the inner surface 12a of the teat wall 12 defines three elongate, substantially radially/axially extending ribs 40a,b. The ribs 40a,b are tangentially equidistantly spaced apart at 120°, such that the placement of the ribs would in itself allow for rotational symmetry (see FIG. 2C). The ribs 40a,b, however, are not identical: rib 40b is thicker than ribs 40a in the sense that it protrudes further from the inner surface 12a of the teat wall 12 (see FIG. 2D). The arrangement of the ribs 40a,b is therefore rotationally asymmetrical. The cross-sectional view of FIG. 3B clearly shows that the rib 40b is partly disposed within the fold region 30 of the teat wall 12, and, more specifically, such that it extends across the local minimum 36 of the annular double fold 32 when the teat 10 is in a depressed state. An advantage of such a rib-shaped wall thickness-defined structure is that it may combine two functions: a lower portion thereof, i.e. the portion disposed within the fold region 30, may serve to avoid a metastable depressed state, while an upper portion thereof, i.e. the portion disposed within the neck 16b of the teat 10 and outside of the fold region 30, may serve to stiffen the neck so as to prevent it from collapsing.

[0044] By way of example, it is noted that, in an alternative embodiment, the rib 40b may have a same thickness as the other ribs 40a, but have a different length, for instance such that it extends across both the local minimum 36 and the local maximum 34 of the annular double fold 32 when the teat 10 is in a depressed state. In such an embodiment the non-uniform length of the ribs 40a, 40b may cause the rotationally asymmetric stiffness distribution, which in the concrete case may be effective because the extra long rib 40b extends across both points of maximum curvature of the double fold 32 while the short ribs 40a merely extend across the local minimum 36 thereof. A similar argument applies to an alternative embodiment wherein the rib 40b may have a (tangential) width different from the other ribs 40a, in which case the extra width of the rib 40b may result in extra unbending force. It is further understood that the above-described wherein a thickness T, a length L or a width W of a rib 40b as exemplary shown in FIGS. 6A and 6B deviates from that of the other ribs 40a may also be combined so as to define a rib 40b having multiple geometric properties that deviate from those of the other ribs, or, more generally, to define a plurality of ribs 40a, 40b having multiple mutually deviating geometric properties.

[0045] The effectuation of a rotationally asymmetric stiffness distribution by means of wall thickness-defined structures offers the advantage that the teat 10 may be manufactured from a single, homogenous material, or at least a material having an elastic modulus that is homogenous throughout the wall 12. This benefits the economic manufacturability of the teat 10.

[0046] In another embodiment, however, the rotationally asymmetric stiffness distribution may be at least partially effected through the use of a rotationally asymmetric distribution of at least two materials having a mutually different modulus of elasticity. In such an embodiment the fold region 30 of the teat 10, which may be generally made of a first constituent material, may, for instance, include rotationally asymmetrically distributed ‘inlays’, portions or patches of a second constituent material having a modulus of elasticity that differs from that of the first. An example, as shown in FIG. 7, are patches 43 being made of the second constituent material with the remaining portion 42 of fold region 30 being made of the first constituent material. An advantage of such an embodiment is that it does not require shape-asymmetries to effect a rotationally asymmetric stiffness distribution in the belt region 30. As regards the placement, shape and size of the inlays, portions or patches, the above discussion of the wall thickness-defined structures is mutatis mutandis applicable (e.g., the description of FIGS. 7A and 7B).

[0047] The teat 10 may preferably be manufactured from a resilient material, such as, for instance rubber, latex, or liquid silicone rubber (LSR). In one embodiment, the teat 10 may be manufactured by injection molding, in which process the teat may be set or cured in its distended position, and provided with the capability and tendency to return to that position when it is distorted therefrom, in particular by depression.

[0048] Now that the construction of the teat 10 according to the present invention has been described in some detail, reference is made to FIG. 4 to illustrate the effect of a fold region 30 with a rotationally asymmetrical stiffness distribution. To this end, FIG. 4 schematically illustrates in four frames taken from a finite element modelling (FEM) simulation how the teat 10 of FIGS. 1-3 may elastically transform from its depressed state (top frame, cf. FIG. 3B) to almost back to its distended state (bottom frame, cf. FIG. 3A). In the FEM simulation the skirt 22 was omitted.

[0049] In the top frame the teat 10 is shown in a depressed state, in which it may held by a negative external-internal pressure differential across the wall 12 of the teat 10. When the pressure differential is removed and the teat 10 is released, the elastic stresses in particular the local maximum 34 and local minimum 36 of the double fold 32 will act to force to the relatively large area of the fold region 30 through the confined annular overlying area, disposed in a plane transverse to the axis L of the teat 10 and radially in between the local maximum 34 and local minimum 36 of the double fold 32. Since the thicker rib 40b bent at the local minimum 36 (see FIG. 3B) has a relatively large stiffness and thus exerts a relatively large ‘unbending force’ that is rotationally unbalanced by that of the thinner ribs 40a, it will unbend first and tilt the nipple 14a out of its initial vertical position; see the second frame. In doing so, it allows the base of the neck 16b to pass through the aforementioned confined annular area first, as is shown in the third frame. When a first side of the teat 10 has been largely unbent, the less stiff areola portion still exhibiting the double fold 32 may similarly relax, thus allowing the teat 10 to pop out into its distended state. This is depicted in the fourth frame.

[0050] With regard to the terminology used in this text, the following is noted. Where the term ‘rotationally asymmetric’ is used with respect to a certain feature of the teat, e.g. a structure, arrangement, configuration, distribution, etc., the term may be construed to mean that said feature does not possess rotational symmetry of an order n>1 with respect to a central axis of the teat. Rotational symmetry of order n, also called n-fold rotational symmetry, or discrete rotational symmetry of the n-th order, with respect to a particular axis may mean that rotation by an angle of 360°/n around that axis effectively maps the feature onto itself. Rotational symmetry of (merely) order n=1 may thus effectively imply the absence of rotational symmetry, i.e. rotational asymmetry. The term ‘axisymmetry’ may be construed to refer to infinite-fold rotational symmetry; a feature that is axisymmetric with respect to a particular axis may map onto itself when rotated around that axis by any (arbitrary) angle. It is also noted here for clarity that a ‘modulus of elasticity’, such as in particular the Young's modulus, may be construed to be an intensive or material property, while ‘stiffness’ may be regarded to be an extensive or structural property.

[0051] Although illustrative embodiments of the present invention have been described above, in part with reference to the accompanying drawings, it is to be understood that the invention is not limited to these embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, it is noted that particular features, structures, or characteristics of one or more embodiments may be combined in any suitable manner to form new, not explicitly described embodiments.

LIST OF ELEMENTS

[0052] 1 infant feeding bottle [0053] 10 teat [0054] 12 resilient teat wall [0055] 12a inner surface of teat wall [0056] 12b outer surface of teat wall [0057] 14a nipple [0058] 14b areola [0059] 16a head [0060] 16b neck [0061] 16c shoulder [0062] 18 interior food reception space [0063] 20 food discharge opening in nipple [0064] 22 skirt [0065] 24 annular groove in skirt for screw ring reception [0066] 26 clamp portion of skirt [0067] 28 oval recession in inner surface of areola [0068] 30 fold region of teat wall [0069] 32 annular double fold [0070] 34 annular local maximum/annular hill [0071] 36 annular local minimum/annular well [0072] 38 global maximum defined by nipple [0073] 40a thin rib [0074] 40b thick rib [0075] 50 screw ring [0076] 60 bottle body [0077] L central axis