Abstract:
A dispensing closure with a hinged flap for conveniently opening and closing a dispensing aperture. The closure is a one-piece molded part having an integral living hinge. A mechanism for releasably locking the flap in a stay-open position and thereby resisting any tendency of the hinge to resiliently bias the flap towards a closed position is provided. The stay-open mechanism comprises a cooperating pair of surfaces molded into the flap and main body of the closure which are arranged to snap into and out of locking engagement when the flap is deliberately moved into or out of the open position.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to plastic dispensing closures or like products with flaps for opening and closing a dispensing aperture. 
     PRIOR ART 
     Dispensing closures for bottles, cans and other containers frequently have one or more flaps that can be pivoted between open and closed positions to conveniently dispense product from the container without removing the closure. Examples of the general type of closures under consideration here are disclosed in the following United States Patents, the disclosures of which are incorporated herein by reference: U.S. Pat. Nos. 4,693,399, 4,936,494 and 5,330,082. 
     Where a flap or flaps are joined to the main body of the closure with an integral hinge, the closure is ordinarily molded of relatively resilient material. The resilient nature of the cap material causes the flap to exhibit a tendency when it is opened and released to spring back or relax towards the closed position. This tendency can be troublesome when the flap assumes a free position which obstructs a dispensing hole or holes in the closure. Numerous techniques have been proposed and used to hold the flap in an open position. Typically, these techniques involve a snap acting or over-center hinge or snap engaging elements apart from the hinge. A specialized hinge can be difficult to mold and can require large areas and/or a location which limits the geometry of the flap on the closure. Frequently, the snap engaging designs require that the closure be formed of two separate parts or have other expensive and/or complex geometries. 
     SUMMARY OF THE INVENTION 
     The invention provides a dispensing closure or similar product having a hinged flap with a mechanism to releasably hold the flap open. The disclosed stay-open feature is relatively easy to mold without complex tooling and offers flexibility to the designer in the selection of a stay-open position and can readily be applied to multiple flap closures. Moreover, the stay-open mechanism of the invention is readily adapted to one piece closures. 
     As disclosed, the invention provides a releasable snap lock mechanism that employs separate formations on the body of the closure and on the flap. The snap lock formation or component on the flap is spaced from the hinge joining the flap to the closure body so that it orbits or pivots around the hinge. The snap lock formation or component on the body lies in the path or orbit of the lock formation on the flap. The body lock formation is located relative to the path of the flap lock formation to determine the position at which the flap is held open and the level of retaining force available to maintain it open. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a cap in a first embodiment of the invention; 
     FIG. 2 is a fragmentary perspective sectional view of the cap of FIG. 1 with one flap open; 
     FIG. 3 is an enlarged fragmentary sectional view of the cap of FIG. 1 with one flap open; 
     FIG. 4 is a view similar to FIG. 3 but with both of the flaps of the cap closed; 
     FIG. 5 is a perspective view of a cap in a second embodiment of the invention; 
     FIG. 6 is a perspective view of a cap in a third embodiment of the invention; and 
     FIG. 7 is a perspective cross-sectional view of the cap of FIG. 6 with a flap open. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIGS. 1-4, there is shown a closure or cap  10  in a first embodiment of the invention. The cap  10  is a unitary or one-piece structure preferably formed of an injection molded suitable thermoplastic material such as polypropylene. The cap  10  has a generally circular end wall  11  and a cylindrical skirt  12  depending from the periphery of the end wall. The skirt  12  is formed with internal threads  13  enabling it to be screwed onto a mouth of a container. Caps of this general type are well known in the art and are disclosed, for example, in the U.S. patents cited hereinabove. 
     A lower face or side of the end wall  11  includes a circumferentially continuous sealing surface  14  that registers with and can engage the mouth of a bottle or container. A removable liner (not shown) such as an induction seal liner, may be positioned in the cap  10  against the sealing surface  14  prior to assembly of the cap on a bottle to assure freshness and tamper evidence by causing the liner to seal on the mouth of the container. 
     The cap  10  illustrated in FIGS. 1-4 is a two-mode design having a relatively large spoon or pouring opening  16  at one side of the end wall  11 , and a plurality of sift or shake openings  17  in an opposite side of the end wall. Each of a pair of flaps  18 ,  19  selectively opens and closes the spoon hole  16  and sift holes  17 , respectively. The flaps  18 ,  19  are integrally joined to a chordal or diametral area  21  of the end wall  11  by respective living hinges  22 . The term “chordal”, as used herein, is intended to cover the special case where the area  21  is symmetrical with a diametral line such as where, as illustrated, the flaps  18 ,  19  are essentially of the same size, but also includes arrangements where the flaps are of unequal size and the area is more distinctly offset from a true diametral line. In the illustrated case, the hinges  22  are elongated elements that extend along a major portion of the chordal area  21  and the width of the respective flaps. The hinges  22  in the illustrated embodiment are parallel to each other. The hinges  22  comprise relatively thin, small areas of material. In a plane transverse to their longitudinal direction, the hinges  22  are relatively small in cross-section as shown in FIG. 3 having small dimensions measured in a direction between the flap and the chordal area  21  (FIG. 4) and measured perpendicularly to this direction. 
     A releasable flap catch mechanism  26  such as disclosed in aforementioned U.S. Pat. No. 5,330,082 is provided to releasably hold each of the flaps  18 ,  19  closed on the end wall  11  to close their respective apertures or openings  16 ,  17 . The catch mechanism  26  includes a hook-like formation  27  with a downwardly facing surface  28  projecting horizontally on the end wall  11  and a complimentary surface formation  29  including an upwardly facing surface  31  (when the flap is closed) and projecting in a plane parallel to the plane of the flap. When closed, the flap catch surface  31  snaps under the end wall snap catch surface  28 . 
     The invention provides a releasable lock arrangement  35  to releasably hold or lock the flaps  18 ,  19  open to facilitate dispensing from the container on which the cap  10  is installed. These releasable locks  35 , in the embodiment of FIGS. 1-4, associated with each flap  18 ,  19  comprise a lock surface  36  on a flap  18 ,  19  and a lock surface  37  on the chordal area  21  of the end wall  11 . In the illustrated embodiment, the lock surfaces  36 ,  37  area positioned adjacent the mid-length of their respective hinges  22 . To accommodate these lock surfaces  36 ,  37  and associated formations, the hinges  22  are interrupted at their mid-length so as to have two parts, one on each side, in the chordal direction, of the lock surfaces  36 ,  37  and the flap has a rectangular aperture or notch  38  through which the lock surface  37  passes. The lock surfaces  36 ,  37  are each adjacent an axis of a respective hinge  22 . The axis of the hinge  22  can be idealized as existing at the center of its cross-section. The lock surface  36  on the flap  18  is oriented, i.e. facing in the same general direction, as that of the underside of the flap. The lock surface  37  associated with the end wall  11  has an orientation that faces away from the closed position of the flap that it is arranged to hold open. 
     As shown most clearly in FIGS. 3 and 4, the lock surface  36  on the flap is aligned with the lock surface  37  on the end wall in the sense that the surfaces are at the same location along a direction parallel with the axis of the hinge. Stated otherwise, the lock surfaces  36 ,  37  are in a common plane radial to the axis of the hinge  22 . 
     In the free states of the portions of the end wall  11  and flap  18 ,  19  providing the lock surfaces  36 ,  37 , the minimum spacing of the lock surface  36  on the flap from the axis of the hinge  22  is less than the maximum spacing of the lock surface  37  on the end wall from the axis of the hinge. This geometry produces an interference between the respective areas of the flap and end wall forming the locking surfaces  36 ,  37 . When a flap  18  or  19  is manually opened and the lock surface  36  on the flap orbits around the hinge axis, the part of the flap forming the locking surface  36  engages the part of the end wall forming the lock surface  37 . The flap, end wall and hinge in the zone of the locking surfaces  36 ,  37  resiliently distort under the influence of a camming action between a surface area  41  on the flap and surface areas  42 ,  43  on the end wall  11 . Upon further manual opening movement of the flap  18 ,  19 , the surface area  41  snaps past the areas  42 ,  43  and the locking surfaces  36 ,  37  snap into positions confronting one another and enabling them to releasably hold the respective flap open against any spring back tendency in the hinge  22 . To close a flap, a manual force is applied in a closing direction and the snap action reverses. Resilient local distortion in the areas of the lock surfaces  36 ,  37  and hinge  22  enable the surfaces to again bypass one another. 
     As seen in FIGS. 1-4, the mid-chordal area  21  of the end wall  11  between the flaps  18 ,  19  is raised above other areas of the end wall, in the illustrated case, by arching the mid-section of this chordal area slightly upwardly from peripheral areas of the end wall. The increased height or elevation of the mid-section of the chordal area  21  serves to visually integrate the local portions of the end wall that serve to form the lock surface  37  and adjacent camming surfaces  42 ,  43  for aesthetic purposes. Additionally, the arched chordal area  21  can serve as a back stop to limit opening movement of a flap  18  or  19 . 
     FIG. 5 illustrates a cap  51  similar to the cap  10  detailed in FIGS. 1-4. The same numerals are used in this embodiment as used in the embodiment of FIGS. 1-4 for the same or similar parts. The locking surfaces  37  on a chordal area  52  of the end wall  11  are formed on an integral block or projection  53  at the mid-length part of the chordal area  52 . The lock surfaces  36 ,  37  work to allow the flaps  18 ,  19  to stay open in the manner described in connection with the embodiment of FIGS. 1-4.  4 . The chordal area  52  is generally flat and coplanar with peripheral areas of the end wall at the sides of the flaps  18 ,  19 . 
     FIGS. 6 and 7 illustrate still another embodiment of the invention in which a cap  70  has an end wall  71 , a cylindrical internally threaded skirt  72  depending from the periphery of the end wall, and a single flap  73  for selectively opening and closing dispensing apertures  76  in the end wall. The end wall  71  has a chordal area  77  on which a lock surface  37  is formed. The flap  73  includes a cooperating lock surface  36 . The lock surfaces  36 ,  37  serve to releasably hold the flap  73  in an open position, illustrated in FIG. 7, in the manner described above in connection with FIGS. 1-4. 
     From the foregoing description, it will be understood that the stay-open feature of the flap locking mechanism  35  is relatively simple in construction and readily molded with relatively simple tooling. Still further, the flap locking mechanism  35  assures that a flap will remain open for dispensing purposes. The locking mechanism  35 , as demonstrated, can be used with a variety of flap structures including caps with a plurality of flaps. The locking mechanism, although shown disposed at the mid-width of a flap can be disposed at another location or locations on the flap. The lock mechanism  35  can be arranged to hold a flap at a desired angular position, typically greater than 90°. 
     While the invention has been shown and described with respect to particular embodiments thereof, this is for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiments herein shown and described will be apparent to those skilled in the art all within the intended spirit and scope of the invention. For example, the invention, besides being employed with screw-on caps such as disclosed herein, can also be employed with friction or adhesive retained or snap-on closures that fit on or in a container. Accordingly, the patent is not to be limited in scope and effect to the specific embodiments herein shown and described nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.