Abstract:
A holder assembly for use with a flexible liner is provided having a holder with a longitudinal slot and a plunger. The plunger has a disk and a positioner joined to the disk. The positioner engages the longitudinal slot to mount the disk slidably in the holder. The plunger is readily adapted for assembly and disassembly with the holder.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a holder assembly for dispensing baby formula and the like. More particularly, this invention relates to a holder assembly that includes a holder for use with a disposable liner or sac, and a sliding member removably secured to the holder for expelling air from the liner.  
           [0003]    2. Description of the Prior Art  
           [0004]    Reusable baby bottles or hard bottles, such as made of glass or plastic, have been commonly used to feed babies formula, water, and other liquids. After liquid is placed in the bottle, a nipple is attached to the bottle and the assembly is ready for use. A hard bottle sometimes is cleaned and sterilized between each use, requiring substantial time and effort.  
           [0005]    An alternative to a hard bottle is the flexible or disposable liner or sac (also referred to as a “disposable bottle”) that is used in conjunction with a holder which supports the liner. The liner, which is used only once, is pre-sterilized, and is inserted into the holder. The liner is then filled with liquid, and a nipple is attached to the holder. This alternative is economical and sanitary, and greatly minimizes the time and effort required to prepare for feeding a baby.  
           [0006]    One limitation inherent in hard bottles is the tendency of babies to ingest substantial amounts of air when ingesting the liquid. This air can cause uncomfortable distention and gas in the baby&#39;s stomach, and may lead to vomiting and other problems. Disposable liners collapse as liquid is drawn out, thus minimizing the amount of air the baby ingests. However, under some circumstances a small amount of air can be drawn into the liner through the hole of the nipple.  
           [0007]    Attempts have been made to address this problem. U.S. Pat. No. 3,998,348 to Sammaritano provides a roller assembly attached to the lower, closed end of the liner to take up the liner as it empties. U.S. Pat. No. 4,796,767 to McKeown provides a pushrod stored on the outside of the holder. When in use, the pushrod is inserted through the open bottom of the holder to press air out of the liner through hole in the attached nipple. U.S. Pat. No. 4,176,754 to Miller provides a donut-shaped pneumatic roller used to press air out of the liner similarly as discussed above.  
           [0008]    Some patents provide a plunger-type insert having the general shape of the inside of the holder. The plunger can be pushed up within the holder to press air out of the liner. Certain devices use a plunger having a stem extending from the open bottom of the holder. Other devices require the user to reach inside the open bottom of the holder to operate the plunger.  
           [0009]    Other patents provide a refinement on this construction employing a plunger-type insert that is operable by means located on the sides of the holder. U.S. Pat. No. 5,356,016 to Wiedemann provides a flat, circular plunger member having a pair of tab handles on its diameter that extend through a pair of longitudinal slots in the holder.  
           [0010]    U.S. Pat. No. 3,955,698 to Hammer is a device somewhat similar to that shown in the Wiedemann patent. However, the Hammer device has a pair of tab handles that engage with ratcheted indentations on the interior surface of the holder. U.S. Pat. No. 5,301,825 to Di Scala et al. provides a related device in which the tab handles are connected in a ring extending around the holder.  
           [0011]    These devices tend to be unwieldy, unstable and awkward. These devices suffer from the drawback of requiring a complex disassembly of the tab or ring handles to clean the holder assembly. This is inconvenient and time-consuming for the user. Also, removable tab handles can pose a danger to the baby as small parts. These devices also suffer from the drawback of requiring two hands to operate properly. The tab handle devices require the user to hold the holder in one hand, and apply pressure, preferably with the other hand, to the opposing tab handles simultaneously. The ring device requires the user to grasp the holder in one hand, and the ring, preferably with the other hand and at opposing points, to slide it. If used with one hand, slight movements of the ring might be possible, but any greater pressure may force the ring&#39;s edge into the holder surface and arrest further movement. These devices additionally suffer from the drawback of being bulkier than the present holder, thereby making these known devices less attractive and more expensive to manufacture.  
           [0012]    Patents disclosing a holder assembly designed to alleviate such drawbacks are disclosed in U.S. Pat. No. 5,878,899 to Manganiello et al. and U.S. Design Pat. No. 411,886, which are assigned to the assignee of the present application. Applicant hereby incorporates the disclosures of these patents by reference. The holder assembly is for use with disposable baby feeding liners and has a holder with a longitudinal slot and a member. The member has a disk and a finger-operated attachment joined to the disk at a single location. The attachment engages the longitudinal slot to mount the disk slidably within the holder. The holder has markings for determining the volume of liquid entering into the liner and the volume of liquid remaining in the liner as the baby is feeding. While a significant improvement over the known devices, this holder can have a simpler assembly and disassembly procedure. This device also does not provide significant leverage to the user for squeezing out the air in the liner.  
           [0013]    Accordingly, there is a need for holders for flexible liners that facilitate assembly and operation while maintaining safety for the infant and reducing cost of manufacture.  
         SUMMARY OF THE INVENTION  
         [0014]    It is an object of the present invention to provide a holder assembly that provides for efficient expulsion of air from a disposable flexible liner or preformed sac.  
           [0015]    It is another object of the present invention to provide such a holder assembly that allows air removal from the liner, and can be held and operated effectively, easily and comfortably by the user, and preferably by use of one hand.  
           [0016]    It is a further object of the present invention to provide such a holder assembly that facilitates operation, assembly, disassembly and cleaning.  
           [0017]    These and other objects and advantages of the present invention are provided by a holder assembly for a disposable liner that expels air from the liner, which comprises a holder having an outer circumference and an axial slot; and a plunger having a disk and a positioner connected to the disk. The disk is removably disposed in the holder and movable in an axial direction in the holder to urge air from the liner. At least a portion of the positioner is accessible from outside of the holder along the axial slot and movable along the axial slot. The plunger engages the axial slot without engaging the holder in an area opposite the axial slot. The holder can have an axial channel inwardly recessed from the outer circumference with the axial channel having a width that allows at least a portion of the positioner to move through the axial channel along the axial slot and the axial slot can be formed in the axial channel.  
           [0018]    In another aspect of the present invention, a holder assembly for a disposable liner that expels air from the liner is provided. The assembly comprises a holder having a first axial track, a second axial track and an outer circumference, and a plunger having a disk and a positioner. The disk is removably disposed in the holder and movable in an axial direction with respect to the holder to urge air from the liner. At least a portion of the positioner is accessible from outside of the holder along the first and second axial tracks. The positioner engages the first and second tracks without engaging the holder in an area opposite the first and second axial tracks. The positioner is movable along the first and second tracks.  
           [0019]    In another aspect of the present invention, a holder assembly for a disposable liner that expels air from the liner is provided. The assembly comprises a holder having an outer circumference, an opening, and an axial slot in communication with the opening and formed by first and second walls, and a plunger having a disk and a positioner connected to the disk. The disk is removably disposed in the holder and movable in an axial direction in the holder to urge air from the liner. At least a portion of the positioner is accessible from outside of the holder along the axial slot. The positioner engages the axial slot along the first and second walls without engaging the holder in an area opposite the axial slot. The opening is at least partially defined by the first and second walls. The positioner can be selectively engaged and disengaged with the axial slot though the opening. The holder can have a first contact area and a second contact area. The first contact area is a first surface area of those portions of the first and second walls that are engaged with the positioner when the positioner is remote from the opening. The second contact area is a second surface area of those portions of the first and second walls that are engaged with the positioner when the positioner is in proximity to the opening. The first contact area can be greater than the second contact area.  
           [0020]    In another aspect of the present invention, a holder assembly for a disposable liner that expels air from the liner is provided. The assembly comprises a holder having an outer circumference and an axial slot, and a plunger having a disk, a positioner connected to the disk and a pad connected to the positioner. The disk is removably disposed in the holder and movable in an axial direction in the holder along the axial slot to urge air from the liner. The positioner engages the axial slot without engaging the holder in an area opposite the axial slot. The pad is accessible from outside of the holder along the axial slot. The pad is made from a first material, and the positioner is made from a second material. The first material is softer than the second material.  
           [0021]    In another aspect of the present invention, a holder assembly for a disposable liner that expels air from the liner is provided. The assembly comprises a holder having an outer circumference, a single axial slot, and a single axial channel. The axial slot is formed by first and second walls and is disposed in the axial channel. The first and second walls have inner and outer surfaces. The holder assembly further comprises a plunger having a positioner. The plunger is partially disposed in the holder and movable along a longitudinal axis of the holder to urge air from the liner. The positioner engages the inner and outer surfaces of the first and second walls. A portion of the positioner is accessible from outside of the holder and adjacent to the axial slot. The axial slot has an opening at its first end. The opening has an area smaller than an area of the portion of the positioner to allow selective removal of the positioner from the holder. The positioner can engage the inner and outer surfaces of the first and second walls without engaging the holder in an area opposite the axial slot.  
           [0022]    In another aspect of the present invention, a holder assembly for a disposable liner that expels air from the liner is provided. The assembly comprises a holder having an axial slot and an opening, and a plunger having a positioner removably engaged with the axial slot. The plunger is partially disposed in the holder and movable along the axial slot to urge air from the liner. At least a portion of the positioner is accessible from outside of the holder and adjacent to the axial slot. The positioner engages the axial slot without engaging the holder in an area opposite the axial slot. The positioner is disengageable from the axial slot by moving the positioner in only a first single direction when the positioner is in proximity to the opening. The positioner can engage with the axial slot by moving the positioner in only a second single direction when the positioner is in proximity to the opening. The second direction can be opposite to the first direction. The first single direction can be a rotational direction. The axial slot can have at least one detent structure disposed adjacent to the opening that allows disengagement of the positioner from the axial slot by movement of the positioner in only the first single direction when the positioner is in proximity to the opening. The detent structure can be a first tapered edge and a second tapered edge. The first tapered edge can be formed on a first wall along a first end of the axial slot adjacent to the opening, and the second tapered edge can be formed on a second wall along the first end of the axial slot adjacent to the opening.  
           [0023]    The holder can have an axial channel inwardly recessed from the outer circumference that has a width that allows at least a portion of the positioner to move through the axial channel along the axial slot. The axial slot can be formed in the axial channel. The holder can be transparent. The holder assembly can further have a nipple ring and a nipple removably securable to the holder. The axial channel can be partially formed by a first wall and a second wall. The first and second walls can be disposed along a bottom of the axial channel and the axial slot can be disposed between the first and second walls. The holder can have an opening in communication with the axial slot that allows for engagement and disengagement of the plunger with the axial slot. The opening can be at least partially formed by the first and second walls.  
           [0024]    The pad can be co-molded with the positioner. The first material can be a thermoplastic elastomer. The axial channel can be partially formed by a third wall and a fourth wall, and the third and fourth walls can be disposed along opposing sides of the axial channel. The holder can have an opening in communication with the axial slot that allows for engagement and disengagement of the plunger with the axial slot, wherein the opening is defined by a portion of the first, second, third and fourth walls. The third and fourth walls can be substantially orthogonal to the first and second walls.  
           [0025]    The positioner can have a plate, a rib, and an actuator. The plate can be secured to the disk. The actuator can be accessible from outside of the holder. The rib can connect the plate to the actuator. The rib can be disposed in the axial slot. The actuator can be at least partially disposed in the axial channel when the plunger is engaged with the axial slot. The rib, the plate and the actuator can define a pair of channels that engage with the first and second walls. The positioner can have a plurality or number of glide ridges that contact the first and second walls when the positioner is moved along the axial slot. In a front view, the positioner can have a square or rectangular shape and the opening can have a trapezoidal shape. The disk can have a circumferential lip to form a cup-like shape.  
           [0026]    The holder can have an upper end with a first diameter and a lower end with a second diameter. The second diameter can be larger than the first diameter. The holder can have a middle portion with a third diameter. The first and second diameters are greater than the third diameter. The lower end can have a stabilizing structure. The stabilizing structure can be an outwardly extending bead.  
           [0027]    Other and further objects, advantages and features of the present invention will be understood by reference to the following. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    [0028]FIG. 1 is a front perspective view of a holder assembly of the present invention;  
         [0029]    [0029]FIG. 2 is an exploded perspective view of the holder assembly of FIG. 1;  
         [0030]    [0030]FIG. 3 is a front view of the holder assembly of FIG. 1;  
         [0031]    [0031]FIG. 4 is a rear view of the holder assembly of FIG. 1;  
         [0032]    [0032]FIG. 5 is a side view of the holder assembly of FIG. 1;  
         [0033]    [0033]FIG. 6 is a top view of the holder assembly of FIG. 1;  
         [0034]    [0034]FIG. 7 is a bottom view of the holder assembly of FIG. 1;  
         [0035]    [0035]FIG. 8 is a top perspective view of the plunger of FIG. 1;  
         [0036]    [0036]FIG. 9 is a bottom perspective view of the plunger of FIG. 8; and  
         [0037]    [0037]FIG. 10 is a side view of the holder assembly of FIG. 1 when the plunger is being disassembled. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0038]    Referring to the drawings and, in particular, FIGS. 1 and 2, there is shown a holder assembly according to the present invention generally represented by reference numeral  10 . The holder assembly  10  includes a hollow body, sleeve or holder  100  and a plate, burper or plunger member  200  adapted to be selectively retained with the holder but movable with respect to the holder.  
         [0039]    The holder assembly  10  may include for use a nipple  300 , a nipple retaining ring  400 , a cap  500  and a disposable or flexible liner  600 . Examples of such liners are found in U.S. Pat. No. 6,123,222 to Richiger et al., U.S. Pat. No. 6,110,091 to Morano, and U.S. Pat. No. 5,806,711 to Morano et al., which are assigned to the assignee of the present application. Applicant hereby incorporates the disclosures of these patents by reference.  
         [0040]    Referring to FIGS. 1 through 7, the holder  100  is preferably a hollow cylindrical tube that is open at an upper end  110  and a lower end  120 . Holder  100  has an ergonomic shape that facilitates gripping by the parent when the feeding process is being prepared and also facilitates gripping during the feeding process. In this embodiment, lower end  120  smoothly transitions into upper end  110  over the length of the holder. Preferably, lower end  120  has a diameter d 1  that is larger than a diameter d 2  of upper end  110 . More preferably, holder  100  has a middle portion with a diameter d 3  that is smaller than diameters d 1  and d 2  such that the holder has a narrowed or reduced waist for the user to hold while feeding. The outer surface of holder  100  can also have gripping structures and/or information, such as, for example, measurements.  
         [0041]    Upper end  110  preferably has a diameter between about 2.0 inches to about 2.4 inches. More preferably, the diameter of upper end  110  is about 2.25 inches. Preferably, lower end  120  has a diameter between about 2.45 inches to about 2.75 inches. More preferably, the diameter of lower end  120  is about 2.56 inches. The enlarged diameter of lower end  120  facilitates access to the interior volume of holder  100  for cleaning and for positioning of liner  600 . The enlarged diameter of lower end  120  also facilitates disassembly of plunger member  200  from holder  100 , as will be discussed later in detail. Holder  100  preferably has a substantially uniform wall thickness of between about 0.03 inches to about 0.10 inches, and more preferably about 0.06 inches. The shape and size, including wall thickness, of the holder  100  facilitates manipulation by the user.  
         [0042]    Lower end  120  of the holder  100  preferably has a bottom edge  125 , which is more preferably in the form of a bead or other stabilizing projection or structure. The edge  125  is preferably about 0.13 inches high and about 0.06 inches wide. Alternative structures can also be used for edge  125  such as, for example, an enlarged solid bottom edge to provide strength and rigidity to the structure. The edge  125  can be flared outward to provide stability to the holder  100  when it is placed in an upright position.  
         [0043]    The holder  100  can be any material that will hold the liner  600  in position therein. The holder  100  is preferably formed of a rigid molded material, such as a rigid thermoplastic that will not warp. More preferably, the holder  100  is made of polypropylene. However, the holder  100  can be made of other materials, such as, for example, polycarbonate or other rigid thermoplastics. The holder  100  preferably is made of a transparent or semi-transparent material that allows the user to view the liner  600  in the holder and also allows the user to view the position of the plunger  200 . Preferably, plunger  200  has a contrasting color with respect to holder  100  to facilitate visual indication of the positioning of the plunger in the holder.  
         [0044]    The holder  100  has a longitudinal or axial recess or channel  130  that is formed by a first wall  132 , a second wall  133 , a third wall  136 , and a fourth wall  137 . First and second walls  132 ,  133  are substantially parallel with the outer circumference of holder  100  and inwardly recessed from the outer circumference of the holder. Third and fourth walls  136 ,  137  are substantially orthogonal to the outer circumference of holder  100  and to first and second walls  132 ,  133 . Preferably, channel  130  extends along a substantial length (from upper end  110  to lower end  120 ) of holder  100 .  
         [0045]    First and second walls  132 ,  133  have a space or slot  150  disposed therebetween. Preferably, slot  150  extends along a substantial length of channel  130 . More preferably, slot  150  is centrally disposed along channel  130 . The channel  130  and the slot  150  preferably have a uniform width or circumferential extant. The width of channel  130  is preferably between about 0.70 inches to about 0.85 inches. More preferably, the width of channel  130  is about 0.77 inches. The width of slot  150  is preferably between about 0.10 inches to about 0.18 inches. More preferably, the width of slot  150  is about 0.13 inches. Channel  130  and slot  150  are guides or tracks for the axial or longitudinal movement of plunger member  200  with respect to holder  100 . Preferably, holder  100  provides at least two guides or tracks for the movement of plunger  200 , i.e., channel  130  and slot  150 . The size of first and second walls  132 ,  133  and third and fourth walls  136 ,  137  are such that the channel  130  facilitates movement of plunger member  200 . First and second walls  132 ,  133 , third and fourth walls  136 ,  137 , and slot  150  have a size and shape that reduce or eliminate lateral movement of plunger member  200 , while allowing axial movement of the plunger along a substantial length of the holder  100 .  
         [0046]    Referring to FIGS. 8 and 9, the plunger member  200  is, preferably, a single integral piece that includes a disk  210  and a tangentially connected positioner  250 . The disk  210  is preferably slim and circular, and corresponds to the interior shape of holder  100 . Where an alternative shape for holder  100  is used, such as, for example, oblong or ellipsoidal, disk  210  would have the corresponding shape so that the disk could move within the interior volume or space of the holder. Disk  210  preferably has a lip  215  about its circumference that forms a cup-shaped surface on the disk. The outer diameter of disk  210  and lip  215  is sized slightly less than the inner diameter of the holder  100  so as to permit the disk to move up and down within the holder. The cup-shaped configuration of the disk  210  can hold the bottom of the liner  600  therein, and can help to prevent the liner from falling or being pinched between the disk and the inner wall surface of the holder  100  as the plunger member  200  slides along the inside of the holder. While disk  210  is preferably integrally formed with positioner  250 , alternatively, the disk and positioner can be secured or attached to each other, such as, for example, adhesive.  
         [0047]    The positioner  250  preferably has a plate  255  that is formed integrally with the disk  210  and extends upward and beyond the lip  215  of the disk. The positioner  250  also has an actuator  260  having a pad  265 , and an elongated bridge or rib  270  that connects the plate  255  and the actuator together, preferably at their center portions. On either side of rib  270  between plate  255  and actuator  260 , there are formed channels  275 . Each channel  275  is designed to accept and engage first and second walls  132 ,  133  of channel  130  such that rib  270  is disposed in axial slot  150 . Channels  275  are engaged with the inner and outer surfaces of first and second walls  132 ,  133 . Plunger  200  is movably secured to holder  100  along axial channel  130  and axial slot  150  but is preferably not secured to the holder on the side opposite the axial channel and slot. The disk  210  is separated from the holder  100  along the side opposite to the axial channel  130  and the axial slot  150 .  
         [0048]    Pad  265  is preferably arched in shape to approximate the contours of the user&#39;s thumb. Preferably, actuator  260  has an upper edge  262  that flares outwardly away from the outer surface of holder  100  to form a thumb-accepting flared surface  267  in pad  265 . Upper edge  262  extends between about 0.25 inches to about 0.85 inches from holder  100 , and more preferably extends about 0.45 inches from the holder. The extended distance of upper edge  262  from the holder  100  provides a user with added leverage for sliding plunger  200  along the inner volume of the holder. This added leverage is of great benefit to the user where a force is needed to squeeze out air from the liner  600 , and is especially significant to facilitate preparation and use of the holder assembly  10  with only one hand.  
         [0049]    Pad  265  is preferably made of a soft material to provide comfort to a user, such as, for example, thermoplastic elastomer (TPE). Preferably, pad  265  has a Shore A hardness between about 30 to about 70, and more preferably about 50. Pad  265  is preferably co-molded with actuator  260 , but the present invention contemplates the use of other attachment methods or structures between pad  265  and actuator  260 .  
         [0050]    When plunger member  200  is to be moved axially upward, the user&#39;s thumb or other finger can engage and press up on the flared surface  267  or the underside of the pad  265 . When plunger  200  is to be moved axially downward, the thumb can rest on and press down on the top side of the same flared surface  267 .  
         [0051]    Channels  275  can also have glide ridges  280  formed along the inner surfaces of either or both of plate  255  and/or actuator  260 . The glide ridges  280  are disposed adjacent to the inner and outer surfaces of first and second walls  132 ,  133  and reduce the contact area between the first and second walls and the positioner  260  to reduce friction when the positioner  250  is moved with respect to the holder  100 . Any number of glide ridges  280  can be used.  
         [0052]    Plunger member  200  and/or holder  100  can have frictional engagement structures, such as, for example, detent or ratcheting structures, to keep the plunger from sliding in slot  150  absent any pressure from the user or to prevent the plunger from sliding back down the holder. The force applied by the user to pad  265  to overcome this frictional engagement would be small enough to allow easy and smooth one-handed operation of holder assembly  10 .  
         [0053]    Referring to FIGS. 1 through 9, channel  130  preferably has a lower end  140  defining an opening  142 . More preferably, opening  142  has a trapezoidal shape. First and second walls  132 ,  133  terminate at the upper extant of opening  142  and have holding or detent structures  145  for selectively holding or retaining plunger  200  in opening  142 . In the preferred embodiment, detent structures  145  are tapered or angled edges of first and second walls  132 ,  133  that partially define the trapezoidal shape of the opening. The opening  142  provides for insertion and removal of plunger  200  into channel  130  and slot  150 , while the detent structures  145  facilitate such insertion and removal by providing a limited resistance to the insertion and removal. Tapered edges  145  provide a reduced contact area, as opposed to the entire width of first and second walls  132 ,  133 , to facilitate the insertion and removal of plunger  200 . In the preferred embodiment, a trapezoidal-like shape is used for opening  142 . However, the present invention contemplates other shapes for opening  142  that provide detent structures  145  to selectively hold plunger  200  in engagement with holder  100  but that can also be overcome with minimal force and manipulation to facilitate the assembly and disassembly of the plunger with the holder. Also, while the preferred embodiment has opening  142  at lower end  140 , the present invention contemplates positioning of opening  142  at other positions along axial channel  130  and axial slot  150 .  
         [0054]    Referring to FIGS. 1 through 10, the user can disassemble plunger  200  from holder  100  by lowering positioner  250  into opening  142  so that plunger  200  is only being retained in channel  130  by tapered edges  145  of first and second walls  132 ,  133 . The user can push down on outer edge  262  of actuator  260  so that the opposite end of plunger  200  is rotated upwards (towards upper end  110  of holder  100 ) as shown by arrow  700  in FIG. 10. The upward rotation of the plunger  200  releases the engagement between channels  275  and tapered edges  145  so that the plunger is disassembled from the holder  200 . The tapered shaped of edges  145  provide for a snap-like disengagement or disassembly of the plunger  200  and holder  100 . The plunger  200  can then be removed from the holder  100  through open lower end  120 . The plunger  200  is reinserted or assembled with holder  100  by reversing this process. The disassembly of plunger  200  from holder  100  preferably requires only movement of the plunger in a single direction  700 . More preferably, the single direction  700  is a rotational direction or movement. Similarly, assembly of plunger  200  with holder  100  preferably only requires movement of the plunger in an opposing single direction, which is more preferably a rotational direction or movement.  
         [0055]    In use, liner  600  is inserted into holder  100 . Liquid is poured into the liner, and nipple  300  and nipple retaining ring  400  are secured to holder  100 , thus securing the liner in the holder. The plunger  200  is moved up firmly against the liner  600  maintaining the pressure on the liner until all the air is purged through an aperture in nipple  300  and a small amount of liquid is dispensed. The holder assembly  10  is inverted into feeding position and the fluid can be withdrawn by the infant. The actuator  260  and pad  265  is pressed with the thumb (or other finger) to slide plunger member  200 , and in particular disk  210 , up within the holder  100 . The disk  210  maintains slight compression on the fluid-filled liner  600  and thereby minimizes any air returning to the liner.  
         [0056]    The upper end  110  of holder  100  has a neck  112 , preferably of reduced diameter, adapted to accept the retaining ring  400 . Preferably, the neck  112  has a threaded surface  115 , which mates with interior threads on retaining ring  400 . Liner  600  can have a rim that rests on the rim of neck  112  of holder  100  and is secured in place by retaining ring  400 . Alternatively, the neck  112  can be a smooth surface and/or biased inward from the top to the bottom in order to receive the retaining ring  400  having an alternative non-threaded interior surface. The bias would be approximately ten degrees to the vertical axis with a tolerance of plus or minus one-half degree. The cap  500  can be removably secured to nipple ring  400 . Preferably, nipple ring  400  has an upper lip  410  with an outer diameter corresponding to the inner diameter of the lower end of cap  500  so that a snap-fit engagement of the cap and lip is provided. Upper lip  410  and/or the lower end of cap  500  can have detents or detent means such as, for example, annular beads, to provide for a snap fit between nipple ring  400  and the cap.  
         [0057]    The present invention having been thus described with particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the appended claims.