CLOSURE FORAWEANING CUP
FIELD OF THE INVENTION The present invention relates to a child's sipper cup which functions as a weaning aid. The closure for the cup has a valve which is opened with bite or lip pressure, thus preventing the use of a nursing motion to withdraw fluid. The valve is comprised of a flexible material having a durometer hardness range of 60-90A.
BACKGROUND INFORMATION The transition from bottle or breast feeding to drinking from a cup is often a difficult transition for a child. The mechanics of drinking from a cup are initially difficult, and there is the loss of pleasure derived from nursing. To facilitate this transition, it would be useful to have a sipper cup which provides something of the feel of a nipple, yet requires bite or lip pressure rather than a nursing motion to remove fluid from a cup. In nursing, the tongue musculature moves in a backward- forward peristaltic (wave- like) motion, and the tongue must protrude beyond the gums for effective suckling. When bite or lip pressure is required to remove fluid from the cup, nursing is prevented, as bite or lip pressure blocks the tongue from protruding beyond the gums.
Some cups have been designed with valves that open by pressure of the lips. For example, U.S. Patent Nos. 4,782,975, 4,828,141 and 4,946,062 disclose a valved spout for a container closure lid. The opening of the valve is a slit and is normally in a closed position. The slit opens by the application of force laterally to the edge of the valve. The valve is formed of flexible and resilient material such as synthetic rubber compositions.
U.S. Patent No. 5,730,336 discloses a valve for a flexible liquid container that can be opened by application of pressure from a user's lips or teeth.
The valve comprises an elongated hollow body ending in a diaphragm having at least one slit, the slit being the opening through which liquid is dispensed. When pressure is applied, the slits open and allow fluid to be expelled from the container.
U.S. Patent No. 4,350,260 discloses a lid for a drinking cup, the lid comprising a mouthpiece extending upwardly from one peripheral edge of the lid. The mouthpiece fits within the user's mouth and has a valve that is operable by
pressure from the user's lips or teeth, and which controls the flow of liquid from the container.
U.S. Patent No. 6,202,877 discloses a container closed by a lid having a flexible gasket which opens upon application of bite or lip pressure to the gasket. However, various problems can be seen in the design of these cups.
The valve may prevent complete emptying of the contents of the cup, leading to the possibility of bacterial contamination or the like. The valve may also not prevent leakage when the cup is overturned or dropped by the child. With prolonged use over time, the opposing sides of the valve which form the slit will fail to fully close, leading to further leakage of the cup. Additionally, the cup lid and valve must be comprised of a material that is flexible enough to allow a young child to open the cup with bite or lip pressure, yet be designed in a manner that discourages or prevents nursing from the valve.
SUMMARY OF THE INVENTION The present invention solves the above need by providing a closure for a sipper cup having a valve that aids in weaning a child from a bottle or breast to a cup. The valve is made from a flexible material such as a thermoplastic elastomer - olefin mixture having unique properties suitable for a child's cup. The durometer hardness of the flexible material must be within the range of 60-90 A. Other flexible materials such as natural or synthetic rubbers and silicone may also be used, as long as they have the desired durometer hardness. The valve is openable by bite or lip pressure only. That is, the nursing action of an infant, which produces a 8-10 in. Hg vacuum, will not produce a significant fluid flow. Additionally, the top of the valve, which bows outward when in use, is designed in such a way to ensure complete emptying of the cup, thus preventing contamination. The valve also minimizes leakage or spills if the cup is dropped or overturned.
It is an object of the present invention, therefore, to provide a sipper cup that aids in weaning a child from a bottle or breast to a cup.
It is an additional object of the invention to provide a sipper cup that can be operated by pressure of the lips or gums.
It is a further object of the invention to provide a sipper cup that is comprised of a material having suitable properties for use in a child's cup.
These and other objects of the invention will become apparent from the following drawings, the detailed description and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS The invention is further illustrated by the following non-limited drawings in which:
Figure 1 is an isometric view of the closure with a closed valve. Figure 2 is an isometric view of the closure with an open valve. Figure 3 is a cross-sectional view of the closure taken along line 3-3 in Figure 2.
Figure 4 is an isometric view of the closure on a container.
Figure 5 is a cross-sectional view of an alternate embodiment of the closure.
Figure 6 is an enlarged cross-sectional view of the closure taken along line 3-3 in Figure 2 (when spout is in relaxed position).
Figure 7 is an enlarged cross-sectional view of the closure taken along line 3-3 in Figure 2 (when spout is in pinched position).
Figure 8 is a cross-sectional view of the closure taken along line 4-4 in Figure 2. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
As shown on Figures 1 and 2, a closure 10 for a drinking cup 1 (Fig. 4) includes a skirt 12, an end wall 14, and a valve 16. The skirt 12 depends from the end wall 14, extending in a downward direction. As shown on Figure 3, the end wall 14 has a first, outer side 18 and a second, inner side 20. An opening 22 extends through the end wall 14. Optionally, the end wall 14 has a small opening 58 (Figure 1) to ease the flow of liquid from the cup and prevent formation of a vacuum. The skirt 12 includes a means to engage the drinking cup 1. As shown in Figure 3, the means to engage the drinking cup 1 is a lip 24 that is structured to engage a ridge on the cup. The means to engage the drinking cup 1 may be any common coupling structure, such as a snap-fit or screw-on lid.
The valve 16 is disposed about the opening 22. The valve 16 extends from the end wall first, outer side 18. The valve 16 has a first transition portion 30, an
elongated flexible body 32, a second transition portion 34, a top 36, and a slit 38. The top 36 can be flat, domed or concave, as any shape that can be made compatible with the valve is suitable. The top 36 includes two flexible portions 40, 42 (Fig. 1), each about 4 to 5 mm in width and having an outer area, 40A, 42A (Fig. 8), a thickened internal bridge 40B, 42B (Fig. 8) of a width between about 1 to 2 mm, preferably .1 to .2 mm, and an inner area 40C, 42C (Fig. 8) of a width about 0.5 to 3.5 mm, preferably 1.3 to 1.8 mm. The slit 38 is disposed between the internal bridge 40B, 42B and inner areas 40C, 42C. The slit 38 is about 5.5. mm long. The outer areas 40A, 42A and inner areas 40C, 42C of the flexible portions 40, 42 have a thickness of not more than about 1.5 mm and not less than about 0.5 mm; preferably the outer areas 40A, 42A of the flexible portions and the imier areas 40C, 42C have a thickness of about 1.0 to 1.2 mm. The thickened internal bridge has a thickness of about 1.0-2.0 mm, more preferably 1.6 to 1.9 mm, most preferably 1.7 to 1.85. With these dimensions, the flexible portions 40, 42 are less likely to become warped after use. Thus, the valve 16 is able to maintain the sealing function longer. In addition, the thickened internal bridge 40B, 42B in combination with an inner area 40C, 42C of reduced thickness provides the valve with a "snap-back" return upon closing, without loss of flexibility. As used herein, the term "flexible portion" will be used to denote the entire flexible portion of the top of the closure, 40, 42, on either side of the slit 38, including the thickened internal bridge portions 40B, 42B, and the outer areas 40A, 42A and inner areas 40C, 42C of thinner dimension. Figures 6, 7 and 8 show this aspect of the invention in more detail.
The flexible portions 40, 42 are structured to move between a closed position (Figure 1) and an open position (Figure 2). In the closed position, the flexible portions 40, 42 have one edge 44, 46 abutting the other flexible portion edge 44, 46. That is, the edges 44, 46 abut each other and are bisected by the slit 38. As detailed below, in the second position, the flexible portions 44, 46 are bowed outward so that the slit 38 is wider. Both the first transition portion 30 and the second transition portion 34 are slanted away from the end wall 14. The valve 16 is made from a flexible material which is preferably a thermoplastic elastomer - olefin polymer material, although other materials having the desired durometer hardness described below, such as natural or synthetic rubbers or
silicone-based materials, are contemplated as being within the scope of the present invention. The elongated, flexible body 32 is preferably shaped as an oval, having two opposing long sides 50, 52 and two opposing short sides 54, 56. The slit 38 extends between the long sides 50, 52. In this configuration, when bite or lip pressure, such as could be applied by a child, is applied to the long sides 50, 52 of the elongated flexible body 32, as shown in Figure 2 by arrows L-L, the two flexible portions 40, 42 move from the first, closed position to the second open position. That is, when a compressive pressure is applied to the oval long sides 50, 52, the flexible portions 40, 42 bow outward thereby making slit 38 wider. The nursing action of an infant or child, more specifically the 8-10 Hg vacuum applied in nursing from a breast or bottle, will not produce significant fluid flow from the valve, distinguishing the valve as a true weaning invention. Additionally, as can be seen in the figures, and in particular Figure 2, the design of the valve, that is, having a top 36 in the closed position and flexible portions 40, 42 which bow outward in the open position, ensures that substantially all liquid can be removed from the cup when the valve is in the open position. In other words the valve does not "trap" any liquid within the cup.
As shown in Figure 4, the closure 10 is structured to engage a cup 1. The cup 1 has a body 2 is structured to hold a liquid. The body 2 cup has a bottom 3, a sidewall 4, and an upper opening (not shown). The cup 1 includes a coupling means, such as a thread (not shown) that is structured to engage lip 24. When the closure 10 is joined to a cup 1, the cup 1 acts as a sipper cup or weaning aid.
The material of the valve and cup lid is preferably a thermoplastic elastomer - olefin polymer mixture which imparts unique properties to the sipper cup. For example, the material is rigid enough to allow the lid of the cup to be screwed or snapped onto the cup itself, and yet flexible enough to enable a 10-month old infant to deform the valve with bite or lip pressure. The material also has good tear resistance, so that pieces of the material will not come off in the child's mouth. This is very important, as it provides an additional safety feature to the cup.
Preferably, the thermoplastic elastomer - olefin mixture will have a durometer hardness in the range of about 60-90A, as measured by the Shore A scale. Any material having a durometer hardness in this range would be suitable for use in the present invention. This hardness range will result in a material having the desired
properties discussed above. More preferably, the durometer hardness will be about 75-85A; and most preferably the durometer hardness will be about 78-80A.
The material used in the lid and valve can also be described in terms of the force required to deform the elastomer and cause the valve to open. As the sipper cup is intended for use by a child in the age range of about 10 months to 3 years, the force required to deform the valve must be within the capabilities of a child in this age range. Typically, this will be about 1.5-9.0 newtons, preferably about 4.0-5.0 newtons.
Any thermoplastic elastomer - olefin mixture can be used, as long as it provides the desired durometer hardness. Suitable thermoplastic elastomers include, for example, those sold under the Versaflex tradename by GLS Corporation of McHenry, Illinois. Most preferred is the thermoplastic elastomer sold under the tradename of Versaflex CL-40, by GLS Corporation.
Similarly, any olefin polymer can be used, as long as it results in a material having the desired durometer hardness. Suitable olefins include, but are not limited to, polyethylene, polypropylene, polyisobutylene, polymethylpentene, and other similar olefins. Most preferred is polypropylene, as it results in a material of superior properties. Preferably, the thermoplastic elastomer and the olefin will be mixed in a ratio of about 8 parts elastomer to about 2 parts olefin, however, the ratio may be between from 6.5-9.5 parts elastomer to about 0.5-3.5 parts olefin. The components are mixed as is well known in the art of injection molding. After the mixture is obtained, the material can be molded in the above described design by methods known in the art.
An alternate embodiment of the closure 110 is shown in Figure 5. In this embodiment, the end wall 114 and the skirt 112 are separate pieces. The skirt 112 includes a generally circular central opening 111 and a flange 113 that extends radially inward. The end wall 114 is sized to be smaller than the diameter of the skirt 112, but larger than the generally circular central opening 111. Thus, the end wall 114 is structured to engage the flange 113. A seal 115 may be disposed between the end wall 114 and the flange 113. When the closure 110 engages the drinking cup 1, the end wall 114 is biased towards the flange 113 thereby making a generally water-
tight interface. The valve 116 is disposed on the end wall 114. The valve 116 is similar to the valve 16 described above.
Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appending claims.