Abstract:
A container for photochemical materials has a frangible closure. The frangible closure has a central weakness and a central portion having a thickness and a central portion of greater thickness than the thickness of the central weakness. A radial weakness connects with the central weakness enabling the central weakness to collapse in response to an applied predetermined force.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is related to U.S. application Ser. No. 09/441,499, filed Nov. 17, 1999, by Scott H. Schwallie, et al., and entitled, “Fluid Transfer system For Photoprocessing Materials;” and U.S. application Ser. No. 09,441,985, filed Nov. 17, 1999 by Scott H. Schwallie, et al., and entitled, “Photochemical Frangible Closure.” 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to the field of emptying flasks or containers containing specific products, and in particular to flasks containing photographic development chemicals. More specifically, the invention relates to a frangible closure for containers containing photographic development chemicals. 
     BACKGROUND OF THE INVENTION 
     Certain chemical products must, prior to their use, be specially mixed with other products of the same nature. For shelf-life reasons or product freshness it is often important for the mixing to be carried out just before use. This is particularly the case with chemical products in photographic processing. Customer requirements for easier handling of these photochemical bottles with less exposure to the chemicals has generated the need for a cap which does not need to be removed or replaced to dispense photochemicals. Seal integrity, customer handling, and recycleability has generated the need for a cap molded from high density polyethylene (HDPE) resin which can seal the bottle and be opened simply by inserting the bottle into processing apparatus. At the present time, each product forming part of such a combination is stored in a plastic flask closed by a liquid tight stopper. The photochemical manufacturing community currently utilizes various methods for sealing bottles filled with photographic development chemicals which includes, but is not limited to: 1) foam/cardboard seal insert inside the bottle cap; and 2) aluminum foil seal welded over the bottle neck opening and covered with a cap. A shortcoming of the aforementioned sealing methods is that they each present a propensity to leak that detracts or prevents recycling of the bottle without removing the cap and seal residue. 
     Another currently available practice for sealing a flask used in the photochemical manufacturing community includes a bottle cap with an integral bottleneck seal and segmented lid section. The cap provides a reliable fluid seal while the segmented lid is rupturable by blades available on existing photographic processing apparatus that tear or rupture the segmented portion of the cap. The aforementioned stopper design utilizes a tear channel or weakness with a rectangular cross-section to bisect half of the frangible lid. 
     While the above cap meets the bottle seal requirements and recycling requirements, it is generally known in the photochemical community that a rather significant shortcoming is the puncturability of the segmented lid. Skilled artisans will appreciate that the downward force (average puncture force of 30.12 lbs. or 134.5 Newtons) required to puncture the segmented lid is beyond the physical capabilities of the average person. 
     Therefore, a need persists in the art to remedy the aforementioned shortcomings by requiring lower puncture forces while maintaining an inexpensive emptying method, as well as complete recycleability of the flask and closure. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the invention to provide a container for photoprocessing materials having a frangible closure that is recyclable, prevents leaks, and opens easily. 
     It is another object of the invention is to provide a frangible closure that collapses along a central weakness and partially along a radial weakness. 
     Yet another object of the invention to provide a frangible closure having at least two hinge points which enables the closure sheet to bend inward towards an adjoining processing container. 
     It is a feature of the invention that a central weakness and a connecting radial weakness in the closure sheet of the frangible closure enables the closure sheet to easily collapse inward toward the container to which it is adjoined. 
     The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, a container for photoprocessing materials, comprises: 
     A container body, an opening and a frangible closure closing said opening, said frangible closure comprising a closure sheet having a central weakness having a thickness and a central portion of greater thickness than the thickness of the central weakness so as to resist shearing of said central weakness; and, a lateral skirt surrounding said closure sheet, said lateral skirt and said closure sheet having at least a partial radial weakness therebetween for cooperating with the central weakness and enabling said central weakness to fracture. 
     The present invention has numerous advantages over current developments. First, the frangible closure of the current invention reduces the puncture forces to an acceptable level. The addition of a gate pad allows the tear channel to be molded through the center of the closure resulting in lower puncture forces while eliminating the possibility of shearing a hole through the top of the closure. The gate pad allows the frangible closure to be center gated eliminating weld lines in the cap that can crack under loads, allowing leakage of photographic chemicals through the cap. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features, and advantages of the present invention will become more apparent when taken in conjunction with the following description and drawings wherein identical reference numerals have been used, where possible, to designate identical features that are common to the figures, and wherein: 
     FIG. 1 is a perspective view of the closure of the invention; 
     FIG. 2 is a section view taken along lines II—II of FIG. 3; 
     FIG. 3 is an isometric view of the inside of the first variant of the frangible closure according to the invention; 
     FIG. 4 is a section view taken along lines IV—IV of FIG. 3; 
     FIG. 5 is a plan view of the installation on which a single flask is depicted; 
     FIG. 6 is a top view of the blade point that punctures the center of the closure sheet; and, 
     FIG. 7 is an isometric view of the container of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to the drawings, and particularly to FIGS. 1-4, the present invention concerns a liquid-tight, removable, frangible closure  12  molded preferably from a recyclable high-density polyethylene (HDPE) material. According to FIG. 1, frangible closure  12  has at least one closure sheet  14  fixed to a lateral skirt  16  enabling the closure  12  to be mounted (for example, by a screw), on the spout of a container or flask, described below. According to FIGS. 2-4, frangible closure  12  has a closure sheet  14  having a central weakness  18  formed substantially through a medial portion  19  of the closure sheet  14 . Central weakness  18  has a thickness and a central portion  22  of greater thickness than the thickness of the central weakness  18 . It is advantageous for central portion  22  of greater thickness to have a thickness greater than the thickness of the central weakness  18  so as to resist shearing of the central weakness  18  due to gate shear in the molding process. In the preferred embodiment of the invention, central weakness  18  is an inverted V-shaped channel. The inverted V shaped channel propagates from the central portion  22  of the closure sheet  14  outward towards the radial weakness (described below). Moreover, the inverted V-shaped channel is preferably molded through the medial portion  19  of the underside of the frangible closure  12 . It allows for lower puncture forces (average puncture force of 24.27 lbs. or 108 Newtons) to collapse the closure sheet  14 , as described herein. The addition of the central portion  22  of greater thickness eliminates the possibility of shearing a hole through the closure sheet  14  during the injection molding process due to gate shear. Moreover, central portion  22  of greater thickness, in the preferred embodiment, is a gate pad molded into the closure sheet  14  having opposed, spaced apart, substantially equal thickness portions  24 . 
     Referring to FIGS. 3 and 4, lateral skirt  16  surrounds the closure sheet  14 . The lateral skirt  16  and the closure sheet  14  have a radial weakness  28  at least partially therebetween which cooperates with the central weakness  18  and enables the central weakness  18  to fracture under an applied force. More particularly, radial weakness  28  is a channel comprising spatially separated hinge points  30  for enabling the central weakness  18  to collapse into the radial weakness  28 . More importantly, the hinge points  30  prevent the closure sheet  14  from separating from the lateral skirt  16  when the closure sheet  14  is under an applied pressure. Each of the preferably two hinge points  30  has a thickness greater than the thickness of the radial weakness  28 . Moreover, hinge points  30  are spatially separated preferably about 180 degrees apart. Further, hinge points  30  are molded into the top of the frangible closure  12  normal from the central weakness  18  allowing the punctured closure sheet  14  to fold away toward the container. 
     The central weakness  18  together with the radial weakness  28 , also referred to as frangible areas, allow the closure sheet  14  of the frangible closure  12  to tear under load across the medial portion  19 . 
     Depicted in FIGS. 2-4, frangible closure  12  may include a plurality of threads  32  on the interior wall  34  of lateral skirt  16  for engaging corresponding threads in a container or flask to which it is connected, as described below. The threads  32  provide a means to reduce leaks from the frangible closure  12  and container when the two are tightly screwed together. Those skilled in the art, however, will appreciate that frangible closure  12  may be designed to snap securely onto the container without the necessity of threads  32  and cooperating threads in the container. 
     Referring to FIG. 1, lateral skirt  16  may include a plurality of outer ribs  36  for facilitating twisting the frangible closure  12  away from the container body. 
     Turning now to FIGS. 5-7, in another embodiment of the invention, a fluid transfer system  50  includes a first container  52  (one or more) containing a fluid and second container  54  in fluid communications with the first container  52 . First container  52  has a body  56 , a neck portion  58  extending from the body  56  and terminating in an opening  60 . A frangible, removable and recyclable closure  62 , having all the features described hereinabove, is affixed to the opening  60  for closing the opening  60  and exposing the fluid therein to fluid communications with the second container  54  in a manner described above. 
     Referring to FIGS. 5-6, second container  54  comprises means, such as perforation member  66 , for applying a force to the central weakness  18  (FIGS. 3-4) thereby collapsing the central weakness  18  into the radial weakness  28 . This enables fluid flow from the first container  52  into the second container  54 . 
     Referring to FIGS. 5 and 7, in operations, the emptying of a first container  52  having the frangible closure  62  of the invention is effected by tipping over first container  52  onto a perforation member  66  disposed inside an emptying orifice (not shown) of second container  54 . The emptying is effected directly through the closure sheet  14  of the frangible closure  12  held in the closed position on the spout of the first container  52 . The central weakness  18  is punctured by the force of the perforation member  66  that causes a portion of the closure sheet  14  to collapse along the central weakness  18  inwardly towards the first container  52 . This puncturing action creates a flow path inside the first container  52  that enables the fluid to flow from the first container  52  into the second container  54 . 
     The invention has been described with reference to a preferred embodiment. It will, however, be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention. 
     PARTS LIST 
       12  frangible closure 
       14  closure sheet 
       16  lateral skirt 
       18  central weakness of closure sheet  14   
       19  medial portion of closure sheet 
       22  central portion of closure sheet  14   
       24  opposed thickness portions 
       28  radial weakness 
       30  hinge points 
       32  threads 
       34  interior wall of lateral skirt  16   
       36  outer ribs 
       50  fluid transfer system 
       52  first container 
       54  second container 
       56  body of first container  52   
       58  neck portion of first container  52   
       60  opening 
       62  alternative embodiment of recyclable closure 
       66  perforation member