Abstract:
A dispensing cap with hinged flaps for opening and closing spoon and shake apertures in the cap end wall. The flaps, which are hinged away from the perimeter of the cap, include sealing plugs for the apertures. The plugs and apertures are formed by tooling elements on the same half of a mold to maintain very precise positioning of the plugs relative to the apertures. This precise positioning of the plugs and apertures allows them to be sized to produce a very light interference or touch fit that effectively stops moisture vapor transmission into the container and sifting of product out of the container to which the cap is fitted but, desirably, has little effect on flap opening and closing force. The sealing effectiveness of the plugs and apertures enables the cap to be used without a sealing liner for the mouth of the container.

Description:
[0001]    This is a continuation-in-part of U.S. patent application Ser. No. 10/342,556, filed Jan. 15, 2003, which application is a division of Ser. No. 09/974,434, filed Oct. 10, 2001, now U.S. Pat. No. 6,510,971, the disclosure of which is incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The invention relates to flap-type dispensing caps or closures for bottles, jars, and like containers.  
         PRIOR ART  
         [0003]    U.S. Pat. No. 4,693,399, now U.S. RE37,634, is an example of a screw-on two-flap dispensing cap with spoon (pour) and shake (sift) dispensing modes. This cap pioneered the use of a liner, initially carried in the cap, and sealed to the mouth of a container when the cap was screwed onto the container. The liner, before it is removed by the end user, serves to seal the container to limit moisture from passing into the container and its contents from escaping the container through unsealed parts of the cap in a manner sometimes described in the industry as “sifting”.  
           [0004]    The referenced prior art cap and others similar to it have been provided with so-called clean-out plugs or skirts on the underside of the flap that fit into respective dispensing holes to reduce or eliminate the problem of these holes becoming plugged with the contents through use and to reduce objectionable “sifting” through the dispensing holes when the flaps are closed.  
           [0005]    Prior art liners, while normally being effective to seal a container before being removed, pose a number of problems for cap manufacturers and packagers. For example, liner stock may be subject to degradation when exposed to elevated temperature, the wrong liner material may be loaded into a machine through human error, the liner stock can have manufacturing defects, exhibit a limited shelf life, pose splicing problems when roll stock is used, may distort into a potato chip configuration so as to not feed properly or be maintained in a cap during bulk shipment of caps, may not achieve a good seal on a bottle, may be mis-punched when formed from strips or roll stock, and may misfeed so that no liner or double liners are assembled into a cap. In sum, liners may pose the most difficult and numerous quality control problems for a cap manufacturer compared to the cap itself.  
           [0006]    From the foregoing, it will be understood that there exists a need for an improved flap dispensing cap that can be used without a liner while limiting entry of moisture into the container and resisting unintended sifting of product when the flaps are closed. The desired cap must be capable of being mass produced with multi-cavity molds to reduce production costs and be competitive in the marketplace.  
         SUMMARY OF THE INVENTION  
         [0007]    The invention provides an improved flap style dispensing cap with a construction that enables it to be used without a liner but which has a flap plug and aperture structure that, when closed, excludes moisture and resists sifting. Additionally, the flap plug and aperture structure is advantageously capable of avoiding excessive resistance to flap opening and closing action.  
           [0008]    One aspect of the invention involves the precise location of each flap plug or seal relative to its associated dispensing opening. This condition is obtained, according to the invention, by molding both the plug and aperture with tooling elements all mounted on the same mold side. In this manner, the related tooling elements forming the plugs and apertures can be very closely aligned with one another and their relative positions are essentially unaffected by what happens on the opposite side of the mold.  
           [0009]    The resulting accuracy of the relative locations of the plugs and apertures is, by virtue of the invention, an order of magnitude greater than that existing in the prior art. This positional accuracy enables the manufacture of caps that can have a moisture vapor and sift-resistant seal and that can be opened or closed with moderate forces. These opening and closing forces are very important from the standpoint of the ultimate user because excessive opening force can result in broken fingernails or other frustrations; excessive closing force can be similarly troublesome. The low force associated with opening and closing of the flaps is attributable to, besides the positional accuracy of the plugs and holes, plug and aperture geometry that produces a light contact seal and full seal engagement only when a respective flap is very close to its fully closed position. A cap constructed in accordance with the invention can be used with a shrink band or wrap to secure the closure to a bottle and secure the flaps closed so as to produce a tamper-evident package.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is a perspective view of a cap of the invention shown from the spoon opening side with the flaps open;  
         [0011]    [0011]FIG. 2 is a perspective view of the cap shown from the shake opening side with the flaps open;  
         [0012]    [0012]FIG. 3 is a plan view of the cap with the flaps open;  
         [0013]    [0013]FIG. 4 is a cross-sectional view of the cap with the flaps open taken in the plane  4 - 4  indicated in FIG. 3;  
         [0014]    [0014]FIG. 5 is a fragmentary cross-sectional view on an enlarged scale of a portion of the spoon opening and associated plug with the spoon flap closed;  
         [0015]    [0015]FIG. 5A is a fragmentary view, on a much enlarged scale, of a typical sealing fit of the spoon plug and aperture;  
         [0016]    [0016]FIG. 6 is a fragmentary cross-sectional view on an enlarged scale of a typical sift hole and associated plug with the shake flap closed;  
         [0017]    [0017]FIG. 6A is a fragmentary view on a much enlarged scale, of a typical sealing fit of a shake plug and aperture;  
         [0018]    [0018]FIG. 7 is a cross-sectional view of mold parts used to manufacture the disclosed cap;  
         [0019]    [0019]FIG. 8 is an elevational view of a package, partially in section, utilizing the disclosed cap; and  
         [0020]    [0020]FIG. 8A is an enlarged fragmentary section view of a part of the package of FIG. 8. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    Referring now to the figures, a cap or closure is shown at  10 . The cap  10  is preferably made by an injection molding process, generally known in the art. The material of the cap can be polypropylene or other suitable thermoplastic material used in the packaging industry. The illustrated cap  10  is unitary, being made in one piece, and has a short cylindrical shape. The cap  10  comprises a generally circular end wall  11 , cylindrical skirt  12 , and flaps  13 ,  14 . The skirt  12  can be formed with internal threads  16  that enable the cap  10  to be screwed onto the complementary neck finish of a bottle, jar or other container  17  (FIG. 8). The illustrated version of the cap  10  has two flaps  13 ,  14 , for dispensing dry particulate product out of the associated container  17 . One flap  13  is for spooning or pouring product, and the other flap  14  is for shaking, sifting, or sprinkling product from the container.  
         [0022]    The illustrated cap  10  is a nominal 53 mm size and has a nominal wall thickness of 0.050″. As shown in FIGS. 1 and 2 and elsewhere, the end wall  11  has a relatively large spoon or pour dispensing aperture or hole  18  on one side (with reference to a chordal area  19  where the flaps  13 ,  14  are joined to the end wall  11  by living hinges  21 ,  22 ) and a plurality of shake dispensing apertures  23  on the other side. The spoon aperture  18  is preferably large enough to accept a teaspoon or larger spoon for spooning out product from the container  17  on which the cap  10  is fitted. Where the opening  18  is an “option” intended for pouring, for example, it can be somewhat smaller than that illustrated, but is still large compared to the wall thickness of the cap, e.g. having a dimension greater than about ten (10) times the cap wall thickness. A further option for the cap is to substitute a plurality of sift or shake holes with appropriate plugs, for the spoon aperture  18  which are normally of a size different from the sift holes  23 . The sift holes or apertures  23 , which can vary in number as needed or desired, are sized to efficiently and controllably dispense product from the container  17  when the container is inverted and shaken.  
         [0023]    [0023]FIGS. 5, 5A,  6 , and  6 A illustrate details of hollow plugs  26 ,  27  on lower sides of the flaps  13 ,  14 , respectively. As shown, walls  28 ,  29  of the plugs  26 ,  27  are relatively thin compared to their depth measured in a direction perpendicular to the nominal plane of the associated flap. The plug  26  for the spoon opening  18 , like the spoon opening  18 , is D-shaped but these elements as mentioned can have other shapes. The plugs  27  for the sift holes  23  are preferably identical to one another and are of circular or annular form. The distal ends of the plug walls  28 ,  29  are rounded and the interior and exterior surfaces  31 ,  32  and  33 ,  34  of the walls are slightly divergent, each about 4° from a line perpendicular to the plane of the respective flap  13 ,  14 . Alternatively, the walls  33 ,  34  can be perpendicular to the plane of the respective flap.  
         [0024]    The dispensing apertures or holes  18 ,  23  are bounded by surfaces  36 ,  38  characterized by exaggerated draft-like configurations so that the apertures are widest adjacent an upper surface  41  of the end wall  11 . The apertures  18 ,  23  adjacent an inner surface or underside  42  of the end wall  11  have aperture surfaces  37 ,  39  more closely aligned or parallel with the axis of the cap at the center of the skirt  12 . These narrow surfaces  37 ,  39  are the areas against which the plugs  26 ,  27  seal.  
         [0025]    The hinges  21 ,  22  are parallel to one another and lie along chordal lines relative to the circular end wall  11  when seen in plan view. The hinges  21 ,  22  are situated above the plane of a main area of the end wall  11  so they are adjacent the plane formed by upper surfaces  46 ,  47 , of the flaps  13 ,  14  when the latter are closed. The flaps  13 ,  14  are releasably held in closed positions by depending catches  48 ,  49  that interact with complimentary receiving areas  51 ,  52  on the end wall  11 .  
         [0026]    In FIG. 7 there is shown a somewhat schematic arrangement of a mold for producing the illustrated cap  10 . The mold parts are shown in a fully closed position where they define the mold cavity. The mold apparatus separates or opens across a plane designated by the numeral  55  in FIG. 7. Mold parts below the plane  55  are stationary on a mold half or platen (not shown) while mold parts above the plane  55  are carried on the moveable mold half or platen (not shown). Molten plastic is injected through a gate  56  into the mold cavity at the underside of the end wall  11  in the chordal area  19  that the hinges  21 ,  22  overlie. The cap end wall  11  and skirt  12  are formed internally by a threaded core  57 . The principal areas of the upper surface  41  of the end wall and undersides  61 ,  62  of the flaps  13 ,  14  are formed by a pair of main slides  63 ,  64 . An upper surface  66  of the chordal area  19  and upper surfaces  46 ,  47  of the flaps  13 ,  14  are formed by a center flap form  67 . Auxiliary slides or sub-slides  68 ,  69  carried in the main slides  63 ,  64  form the perimeter or boundary surfaces  36 ,  37  and  38 ,  39  of the dispensing apertures  18 ,  23 . The auxiliary slide  69  additionally forms portions of the upper surface  41  of the end wall surrounding the shake apertures  23 .  
         [0027]    Study of FIG. 7 and the preceding discussion reveals that the plugs  26 ,  27  on the underside of the flaps  13 ,  14  are formed by the respective main slides  63 ,  64 . The cap  10  is released from the mold by first withdrawing the auxiliary slides  68 ,  69  upwardly in the orientation of FIG. 7 by linkages or cams, for example, and then withdrawing the main slides  63 ,  64  (horizontally in FIG. 7) by linkages or cams, for example, and then by separating the platens at the plane  55 . A stripper ring  70  forces the cap off the threaded core  57  in a known manner.  
         [0028]    It will be seen that the boundaries or peripheries of the dispensing apertures  36 ,  37  and  38 ,  39  and their respective plugs  26 ,  27  are formed by tooling elements of the mold situated on the same mold half or platen. This arrangement is unusual for caps of the general type described, i.e. where the flap hinge is spaced inwardly from the periphery of the closure and the flap is molded within a projection of the plan view of the end wall  11 . For example, the flaps in the illustrated case are molded at 90° to the plane of the end wall  11 . Normally, in the prior art the apertures are formed by tool elements on one part or platen and the plugs are formed on the other mold part or platen. The disclosed arrangement where the plugs  26 ,  27  and apertures  18 ,  23  are formed by elements on the same mold part or platen yields much greater precision in the relative positions of the plugs and apertures in the molded product. This positional accuracy enables the plugs  26 ,  27  and apertures  18  and  23  to be sized for a very light interference or touch fit of about 0.0015 to 0.004″, for instance, interference across a diameter of a circular plug or in the case of the spoon opening  18  between opposite sides of the opening.  
         [0029]    The light or touch fit between the plugs  26 ,  27  and apertures  18 ,  23  achieved by the invention is advantageous because it does not significantly affect the opening and closing forces required to open or close a flap  13 ,  14  over that required to release or reset a catch  48 ,  49 . Moreover, influence of opening and closing action force by the plugs  26 ,  27  and apertures  18 ,  23  is reduced where the relatively large draft or relief angle of the surfaces  36 ,  38  exists for a major part of the vertical height of the aperture. There is essentially no interference between the plug and aperture until the part of a plug distal from the flap engages the actual sealing area or surface  37 ,  39  of an aperture. Each sealing area  37 ,  39 , by design, is preferably substantially less in height than the height or thickness of the end wall  11 . Sealing occurs only when the catch  48  or  49  is nearly locked onto its receiving area or structure  51  or  52  on the end wall. At other positions of a flap, there is essentially no frictional drag between the flap plugs  26 ,  27  and apertures  18 ,  23 . The hollow construction of the plugs  26 ,  27  and their relatively thin walls, where their wall thickness is several times less than their height, reduces the forces required to move the plugs into their respective apertures  18  and  23  since the plugs are capable of deforming slightly to conform to the size and relative position of their respective apertures.  
         [0030]    [0030]FIGS. 5 and 6 illustrate a manner by which the relatively “blind” pockets of the mold that form the plugs  26 ,  27  are assured to be substantially filled with the plastic cap material and by which voids due to trapped gas are substantially avoided. Areas of the mold corresponding to local thin wall areas  73 ,  74  of the flaps adjacent the pockets forming the plugs  26 ,  27  remote from the gate  56  serve as flow restrictions upstream from those portions of the plug cavity areas remote from the gate so that plastic tends to flow into and through the plug cavity areas before plastic flows completely past a plug cavity. This allows gas to escape a plug cavity before it is closed off by the lead edge of the main flow of plastic through the main part of the flap cavity. In the illustrated case, as shown in FIG. 7, the flaps  13 ,  14  are molded at 90° to the plane of the end wall  11 .  
         [0031]    [0031]FIGS. 8 and 8A illustrate a package formed by the cap  10  in combination with the bottle  17  and a shrink wrap band or label  76 . The band  76 , in the illustrated example, is relatively short in comparison to the height of the bottle  17 , but it will be understood that it can extend along the full height of the bottle to serve as a full label. The band  76 , as is known in the art, can be printed with advertising and/or directions for use of the contents of the bottle  17 . The band  76 , when shrunk by application of heat or other medium, cups over the outer periphery of the flaps  13 ,  14  to prevent them from accidentally opening or being deliberately opened without evidence of the same in the form of a fracture or tearing of the band.  
         [0032]    It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.