Patent Publication Number: US-7717284-B2

Title: Flip top cap

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This Application claims priority to U.S. Provisional Application No. 60/591,273, filed Jul. 27, 2004, the entire contents of which are incorporated by reference herein. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a flip top cap for use with laboratory vessels, such as tubes. 
   2. Description of the Related Art 
   Many laboratory procedures require tissue cultures or cell cultures to be stored and/or cultivated in a vessel, such as a tube or a flask. The typical tube includes a cylindrical side wall, a closed bottom and an open top. The closed bottom often is conically generated. The size of the tube varies from one laboratory procedure to another, and tubes typically will define volumes from 15 mL to 50 mL. Flasks also have a side wall, a closed bottom and an open top. For simplicity, the following discussion will describe tubes, but pertains to other laboratory vessels as well. 
   Many laboratory procedures require the tissue or cell cultures in the tube to remain sterile. Thus, the tube typically is provided with a cap for sealing the open top of the tube. However, the cap must be removed periodically to access the tissue or cell cultures in the tube. 
   Many caps are formed separate from the tube and have a portion dimensioned for telescoping partly into the tube and sealing with the inner surface of the side wall adjacent the open top of the tube. These caps may be formed from an elastomer or other resilient material to ensure sealing with the tube. Other caps include a substantially rigid collar surrounding portions of the cap that telescope into the tube. The collar can be telescoped over the open top of the tube and provides a region that can be gripped conveniently for removing the cap from the tube. 
   Laboratory workers generally place the cap top-down on a laboratory work surface while they are accessing the interior of the tube with a pipette to obtain a sample of the cell or tissue culture in the tube. Thus, the side and bottom of the cap do not contact the potentially non-sterile work surface. The cap then is repositioned in sealing engagement with the open top of the tube after the cell or tissue culture has been accessed. These tube and cap combinations require the laboratory worker to use two hands to remove the cap. Additionally, these tube and cap combinations create the potential that the cap will be positioned improperly on the work surface, thereby creating the potential for contaminants being transferred from the work surface to the tissue or cell culture in the tube. 
   Some tubes have been manufactured with a flip cap to permit one-handed opening and to avoid the need to place any part of the cap on a laboratory work surface while the interior of the tube is being accessed by a pipette. These tube and cap assemblies typically include a body that is threaded or otherwise mounted to the open top of the tube. A cap is connected to the body by a hinge, such as a living hinge. A laboratory worker holds the tube between the forefingers and the palm of one hand. The thumb of the same hand then is urged against the cap to move the cap out of engagement with the body so that the cell or tissue culture in the tube can be accessed. These flip top caps provide certain handling efficiencies and avoid the need to place the cap on the work surface in the laboratory while the contents of the tube are being sampled. However, prior art flip top caps require the user&#39;s thumb to pass directly over the open top of the tube. There is a high probability that the user&#39;s thumb will contact the open top of the tube while the cap is being rotated away from the open top of the tube. Contact of the thumb with the open top of the tube is likely to contaminate the tube and the tissue or cell cultures stored therein. 
   In view of the above, it is an object of the subject invention to provide a tissue culture vessel, such as a tube, that can be opened easily without significant risk of contamination to the contents of the vessel. 
   SUMMARY OF THE INVENTION 
   The invention is a cap for a laboratory vessel, such as a tube. The vessel includes an open top, and the cap includes a lid that is hingedly secured in proximity to the open top of the vessel. Thus, the lid can be rotated hingedly from a closed position where the top of the vessel is closed and an open position where the top of the vessel is open. The open position is angularly spaced from the closed position by at least 90° and preferably about 180°. 
   The lid of the cap may be joined to a body and the body may be mounted to the open top of the vessel. For example, the vessel may include an array of threads, and the body may include an array of mating threads for securely mounting the body to the vessel. The body and the lid may be joined unitarily to one another by a living hinge. The living hinge may be an over-center hinge that is biased towards a fully closed position and/or a fully opened position. Thus, the over-center hinge will assist complete opening and/or complete closing of the lid. 
   The cap preferably includes at least one tab, and most preferably two tabs extending outwardly from the lid. The tab preferably is offset from a line that passes perpendicular to the rotational axis of the hinge at a location centrally along the hinge. The offset positioning of the tabs offsets the thumb or forefinger of the user from the open top of the vessel, and hence reduces the possibility of contact with the open top of the vessel. Hence, the potential for contamination of cell or tissue cultures in the vessel is reduced. Some embodiments may have no tab and may have surface textures or configurations on the lid to facilitate opening. 
   The lid preferably includes a shield disposed to at least partly surround the open top of the vessel when the lid is in the closed position. The shield is at a side of the lid opposite the hinged connection and preferably extends along at least portions of the lid that have the tab. More particularly, the shield preferably is disposed inwardly from the tab, and hence between the tab and the vessel. Accordingly, the shield cooperates with the tab to prevent contact with the open top of the vessel as the lid is being opened by a thumb or forefinger. The shield also prevents contact with portions of the lid that seal the open top. 
   The lid may further include a skirt dimensioned to telescope into the open top of the vessel or into the open top of the body mounted to the vessel. The skirt is dimensioned for sealed engagement with the open top of the vessel or with the body to achieve sterile containment of cell or tissue cultures in the vessel. Outer circumferential portions of the skirt may include anti-splash features, such as notches. The notches or other such anti-splash features balance air pressure between the inside and the outside of the vessel during the initial stage of opening the lid, and hence reduce the possibility of spraying or splashing as the lid is opened. The shield and the tab are disposed to prevent inadvertent contact with the skirt while the lid is being opened. 

   
     BRIEF DESCRIPTIONS OF THE DRAWINGS 
       FIG. 1  is a perspective view of a cap in accordance with the invention. 
       FIG. 2  is a top plan view of the cap shown in  FIG. 1 . 
       FIG. 3  is a cross-sectional view of the cap taken along line  3 - 3  in  FIG. 2 . 
       FIG. 4  is a side elevational view of the cap. 
       FIG. 5  is a top plan view of the cap in the closed position. 
       FIG. 6  is a side elevational view of the cap in the closed position. 
       FIG. 7  is a perspective view of the closed cap mounted to a tube and showing the cap from the top side. 
       FIG. 8  is a perspective view of the closed cap mounted to a tube and showing the lower side of the cap. 
       FIG. 9  is a first perspective view of the open cap mounted to the tube. 
       FIG. 10  is a second perspective view of the open cap mounted to the tube. 
   

   DETAILED DESCRIPTION 
   A cap in accordance with the invention is identified generally by the numeral  10  in  FIGS. 1-10 . Cap  10  is molded unitarily from resin and includes a body  12  and a lid  14  that are joined unitarily by a living hinge  16 . Hinge  16  enables lid  14  to be rotated approximately 180° between a fully open position, as shown in  FIGS. 1-4 , and a fully closed position, as shown in  FIGS. 5 and 6 . Additionally, hinge  16  has an over-center design configured to bias lid  14  through the final stages of rotation towards the open position of  FIGS. 1-4  and towards the final stages of rotation towards the closed open position of  FIGS. 5 and 6 . 
   Body  12  includes a generally planar top wall  18  with a circular outer periphery  20  and a circular opening  22  concentric with outer periphery  20 . A short cylindrical inner wall  24  extends down from top wall  18  concentrically with circular opening  22  in top wall  18 . Thus, circular opening  22  and inner wall  24  define a short cylindrical sealing surface  26  facing inwardly on body  12 . 
   Body  12  further includes a substantially cylindrical outer wall  28  extending down from outer periphery  20  of top wall  18  and concentric with inner wall  24 . Outer wall  28  has an array of internal threads  30  facing inwardly thereon, as shown in  FIGS. 1 and 3 . 
   Lid  14  includes a substantially planar top wall  32  that is joined unitarily to top wall  18  of body  12  by hinge  16 . Thus, top wall  32  of lid  14  can be rotated about a rotational axis “x” defined by hinge  16  and relative to top wall  18  of body  12 . Top wall  32  of lid  14  has opposed inner and outer surfaces  34  and  36 . Inner surface  36  faces up in the open position of lid  14  as shown in  FIGS. 1-3 . However, inner surface  36  of top wall  32  faces down and opposes top wall  18  of body  12  when lid  14  is in the closed position of  FIGS. 5 and 6 . 
   A substantially cylindrical skirt  38  extends perpendicularly from inner surface  36  of top wall  32  and is dimensioned for sealing engagement with sealing surface  26  of body  12  when lid  14  is rotated into the closed position of  FIGS. 5 and 6 . A plurality of anti-splash notches  40  are formed in the outer circumferential surface of skirt  38  along a side of skirt  38  substantially opposite hinge  16 . Notches  40  extend from the edge of skirt  38  spaced from top wall  32  but terminate at locations spaced from inner surface  36  of top wall  32 . Anti-splash notches  40  permit a flow of gas during early stages of movement of lid  14  from the closed position of  FIGS. 5 and 6  towards the open position of  FIGS. 1-4  to balance air pressure on opposite sides of cap  10  and to avoid a splashing or spraying of liquid that could otherwise occur with a very rapid change of air pressure. However, anti-splash notches  40  are not always required and may not be present on some embodiments. 
   Lid  14  further includes an outer wall  42  that projects perpendicularly from inner surface  36  of top wall  32  at a location spaced outwardly from skirt  38 . Outer wall  42  is substantially cylindrically generated about a longitudinal axis that is perpendicular to and spaced from rotational axis “x” of hinge  16 . Additionally, outer wall  42  defines an inside diameter that exceeds the outside diameter defined by top wall  18  and outer wall  28  of body  12 . Thus, outer wall  42  of lid  14  can be telescoped partly over body  12 . Outer wall  42  includes a shield  44  that extends through an arc on a side of outer wall  42  substantially opposite hinge  16 . Shield  44  of outer wall  42  preferably extends through an arc of between about 135° and about 320°. Portions of shield  44  that extend beyond 180° preferably should have a reduced height to facilitate opening and closing. In the illustrated embodiment, shield  44  of outer wall  42  extends through an arc of approximately 180° at a maximum height. Outer wall  42  further includes short sections  46  that extend from opposite circumferential ends of shield  44  towards hinge  16 . The height reduction achieved through short sections  46  of outer wall  42  permit lid  14  to be rotated efficiently from the open position of  FIGS. 1-4  to the closed position of  FIGS. 5 and 6  without interference with body  12 . In the preferred embodiment, shield  44  of outer wall  42  defines a height of between approximately 0.4-0.7 inch, and preferably about 0.54 inch. 
   Lid  14  further includes tabs  50  and  52  that extend outwardly from shield  44  substantially in the plane defined by top wall  32  of lid  14 . Tabs  50  and  52  are disposed at locations on lid  14  spaced circumferentially from hinge  16 . More particularly, each tab  50 ,  52  extends from a side location spaced circumferentially approximately 90° from a center line “c” that passes perpendicularly through rotational axis “x” at the center of hinge  16 . Additionally, tabs  50  and  52  extend towards a distal location on top wall  32  substantially diametrically opposite the intersection of center line “c” and rotational axis “x” of hinge  16 . 
   Each tab  50  and  52  has a shape substantially conforming to an isosceles right triangle that has a rounded right angle corner and a concave hypotenuse conforming to the outer circumferential surface of shield  44 . The maximum radial extent of each tab  50  and  52  is disposed at a position spaced approximately 135° from the intersection of center line “c” and rotational axis “x” of hinge  16 . The maximum extent of tabs  50 ,  52  from shield  44  is sufficient to provide a secure and convenient engagement surface for a thumb or forefinger during opening of lid  14  relative to body  12 . Preferably the maximum extent of tabs  50  and  52  is in a range of 0.2-0.4 inch. One or more tabs can be disposed at other locations on lid  14  and the tabs can take other configurations. For example, tabs  50  and  52  can be diametrically opposite and may extend normal to center line “c”. Still further, lid  14  can be opened by structure or surface configurations other than tabs. For example, lid  14  can have external roughening, ribs, grooves, indentations or the like. 
   Cap  10  can be employed with a laboratory vessel, such as tube  60  illustrated in  FIGS. 7-10 . Tube  60  has a cylindrical side wall  62 , a closed conically generated bottom wall  64  and an open top (not shown). Portions of side wall  62  adjacent the open top have an array of external threads dimensioned and configured for threaded engagement with internal threads  30  on body  12  of cap  10 . Thus, outer wall  28  of body  12  surrounds portions of cylindrical side wall  62  of tube  60  adjacent the open top of tube  60 . Additionally, top wall  18  of body  12  rests on the open top of tube  60  and inner wall  24  of body  12  telescopes into cylindrical side wall  62  at the open top of tube  60 . Lid  14  generally is in the closed condition illustrated in  FIGS. 7 and 8  for securely sealing the interior of tube  60  and maintaining sterility for the interior of tube  60  and any cell or tissue cultures stored therein. In this closed condition, inner surface  36  of top wall  32  of lid  14  engages against top wall  18  of body  10 . Additionally, skirt  38  is telescoped into sealing engagement with sealing surface  26  defined by opening  22  in top wall  18  and inner wall  24 . 
   The contents of tube  60  may have to be accessed periodically by a pipette or the like to either remove culture from tube  60  or to deposit additional growth medium into tube  60 . For this purpose, a laboratory worker grips side wall  62  of tube  60  between the forefingers and palm of a hand so that the thumb of that hand faces upwardly toward cap  10 . The thumb then is urged against tab  50  or  52  and lid  14  is pushed up and away from body  12 . As a result, lid  14  begins to rotate about hinge  16  and out of engagement with body  12 . Notches  40  move past sealing surface  26  of body  12  during the initial movement of lid  14  to balance pressure on opposite sides of cap  10  and to avoid splashing or spraying that could otherwise occur with a sudden change of pressure. The over-center design of hinge  16  initially will resist rotation of lid  14  from the closed position shown in  FIGS. 7 and 8 . However, the over-center design of hinge  16  then assists rotation beyond about 90°, and accelerates lid  14  into the fully open condition illustrated in  FIGS. 9 and 10 . 
   Tabs  50  and  52  are in offset positions relative to centerline “c” passing centrally through hinge  16  perpendicular to rotation axis “x”. Hence, the thumb used to open lid  14  necessarily will be in an offset position and is not likely to pass directly over opening  22  in top wall  18  of body  12 . Additionally, tabs  50  and  52  are spaced outwardly from shield  44 . Accordingly, shield  44  will separate the thumb of the user from opening  22  in top wall  18  and from skirt  38  as the thumb moves for rotating lid  14  from the closed position of  FIGS. 7 and 8  to the open position of  FIGS. 9 and 10 . Accordingly, the disposition of tabs  50  and  52  and the disposition of shield  44  cooperate to prevent digital contact with areas of body  12  near opening  22  and hence prevent contamination. Additionally, cap  10  remains securely connected to tube  60  in both the open and closed conditions of lid  14 . Accordingly, there is no risk of a cap being placed improperly on a work surface while the contents of tube  60  are being accessed. Still further, cap  10  permits convenient one-handed opening and closing and allows the laboratory worker to use the other hand for manipulating a pipette or other access device. 
   Lid  14  can be rotated from the open position in  FIGS. 9 and 10  back to the closed position of  FIGS. 7 and 8  after the interior of tube  60  is accessed. The shortening of outer wall  42  along sections  46  nearer hinge  16  enables lid  14  to be rotated into the closed position without interference with any part of body  12 . Furthermore, the user inherently will engage portions of tabs  50  and  52  aligned with outer surface  34  of top wall  32  for moving lid  14  to the closed position of  FIGS. 7 and 8 . Hence, contamination with opening  22  is prevented during closing. 
   The invention has been described with respect to a preferred embodiment. However, changes can be made without departing from the scope of the invention defined by the appended claims. For example, the lid may be formed unitarily with the tube or other such vessel. This design option will avoid the need for providing a cap with a body that is hingedly attached to the tube or other vessel. 
   The lid  14  can be provided with only one of the tabs  50  and  52 . 
   The tabs  50  and  52  can be disposed in an even more offset disposition and spaced further from the center line “c” passing perpendicularly through the rotational axis “x” defined by the hinge  16 . 
   The hinge  16  need not be a living hinge and need not be of over-center design. For example, a hinge with plural parts snapped or otherwise connected can be provided.