Abstract:
A packaging container for photosensitive film has a detent locking and unlocking feature that provides light-tight closure of the container compartment to protect the product from the penetration of light. A protuberance formed in the container compartment interlocks with a notch formed in the closure for preventing axial movement of the closure. The interlocked protuberance and notch form the light-tight packaging container.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates generally to the field of packaging, and in particular to packaging for long rolls of photosensitive web material. More specifically, the invention relates to a light-tight packaging container, which includes features for keeping the container securely closed to ensure light-tightness during shipping and storage.  
         BACKGROUND OF THE INVENTION  
         [0002]    Typically, long rolls of photosensitive web material, e.g., photographic film used for surveillance, social/portrait, and commercial imaging are commonly packaged in containers ensuring light-tightness from the manufacturer to the film processor. The rolls of photographic film are wound onto cores with or without flanges. The light-tight containers generally have a film compartment and a closure adapted to fit rather snugly about the film compartment. The containers are often fabricated of metal or plastic.  
           [0003]    It is well known that the closure for such film containers must be securely attached to the film compartment to ensure light-tightness during shipping and handling. An existing practice for securing the closure to the film compartment is by wrapping some sort of opaque or partially opaque adhesive material, such as tape, around the circumference covering the seam between the closure and film compartment. Generally, the manufacturer of photographic film product would apply the adhesive material or tape to the seam between the film compartment and the closure in a dark environment to ensure light-tightness of the product in the package during shipping and handling from the factory to the photographer. When the product is ready to be used, the photographer removes the tape from the seam and disposes of it in the environmental waste stream. The photographer then must hold the packaging container in a light-tight closed condition until it has been inserted into a dark film-changing bag or enters a dark room. While in the dark environment, the photographer then opens the packaging container, removes the film and installs it in the camera. After exposing the film, the photographer uses a dark film-changing bag or dark room to remove the film from the camera and places the exposed film back into the light-tight packaging container. The photographer then secures the packaging container with the closure in a light-tight closed position about the film compartment and then wraps a tape about the seam to ensure light-tightness during shipping and handling from the photographer to the photo-finishing laboratory. The film processor or photo-finishing laboratory would then have to remove and dispose of the tape securing the seam between the closure and the film compartment in order to access the film.  
           [0004]    It should be appreciated that existing packaging containers for photosensitive film product have numerous shortcomings. For instance, the adhesive material or tape introduces added labor cost to the film manufacturer who must provide operators to apply it. These operators would also be exposed to the possibility of injuries when they cut the tape in a dark environment. Moreover, the tape introduces an undesirable cost burden to the film manufacturer who must apply the tape to the container to protect the photosensitive product. Further, the tape is a waste burden to the photographer who removes the tape and must dispose of it. Still further, the tape is a cost burden to the photographer who must re-tape the film container before shipment to the processing lab. Finally, the tape is a waste burden to the processing lab that must remove the tape to access the exposed film and, therefore, must dispose of it.  
           [0005]    Illustrative of existing containers having threaded and lockable closure elements primarily for safety and health is described in U.S. Pat. No. 5,816,422, Oct. 6, 1998, titled, “Package With Safety Lid and Seal,” by Roig. According to the &#39;422 patent the container has projections  5 ,  6  in the closure that mate with recesses  9  and  10  on the body. The integrity of the locking mechanism in the aforementioned patent does not conform to the requirements of light-tightness as does the present invention.  
           [0006]    Therefore, a need persists for a packaging container for photosensitive film product that replaces the need for tape to ensure light-tight protection of the film product, which is simple to use and cost effective to produce.  
         SUMMARY OF THE INVENTION  
         [0007]    It is, therefore, an object of the invention to provide a light-tight packaging container for photosensitive film product that is easy to access in a dark environment.  
           [0008]    Another object of the invention is to provide a light-tight packaging container that can be easily resealed in a dark environment without the need for additional materials.  
           [0009]    Yet another object of the invention is to provide a light-tight packaging container for photosensitive film that resolves the problem of adding product to the environmental waste stream.  
           [0010]    It is a feature of the invention that a first detent feature formed on a flange of the film compartment interlocks with a cooperating second detent feature formed in the closure to secure the film compartment from the penetration of light.  
           [0011]    To solve these and other objects, features and advantages of the invention, there is provided, in one aspect of the invention, a light-tight packaging container comprising:  
           [0012]    A light-tight packaging container, comprising a generally cylindrical container compartment having a base, sidewalls surrounding said base, and an central opening opposite said base, said sidewalls having a flange extending at least partially therearound, and wherein said flange includes a first detent feature extending axially therefrom; and, a generally cylindrical closure configured for fitting over at least a portion of said sidewalls thereby closing said opening, said closure having a second detent feature formed in a peripheral end edge for interlocking with said first detent feature in said flange thereby securing said closure from axial movement along said flange.  
           [0013]    The present invention has numerous advantageous effects over current developments. First, it eliminates the need for an adhesive tape to secure the seam between the closure and product compartment to ensure a light-tight condition inside the product compartment. Next, it eliminates the cost and waste associated with the adhesive tape. Further, it is simple and cost effective to manufacture. And, the packaging container of the invention is easy to use.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    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:  
         [0015]    [0015]FIG. 1 is an isometric view of the closed packaging container of the invention;  
         [0016]    [0016]FIG. 2 is an isometric view of the closure showing the detention feature;  
         [0017]    [0017]FIG. 3 is an isometric view of the article compartment showing the detention feature;  
         [0018]    [0018]FIG. 4 is an enlarged view of the film compartment and closure detention feature interface;  
         [0019]    [0019]FIG. 5 is an isometric view of an alternative light-tight packaging container closure showing the detention and thread features; and,  
         [0020]    [0020]FIG. 6 is an isometric view of an alternative article compartment showing the detention and thread features.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Turning now to the drawings, and in particular to FIGS.  1 - 4 , a packaging container  10  and or components thereof suitable for storing and shipping, under light-tight conditions, an article, e.g., a roll of photosensitive film, is illustrated. In FIGS. 1 and 4, the closed packaging container  10  of the invention is depicted having a container compartment  12  and a closure  22  (described below) fitted snugly about the container compartment  12  in a manner that prevents the penetration of light. According to FIG. 2, packaging container  10  has a container compartment  12  having a generally cylindrical shape. As shown in FIG. 2, container compartment  12  has a substantially circular base  14 , sidewalls  16  surrounding the base  14  and an opening  17  opposite the base  14  for accessing the container compartment  12 . In a preferred embodiment, the sidewalls  16  have a flange  18  that extends at least partially around the circumference of the container compartment  12 . Importantly, the flange  18  includes a first detent feature, preferably a protuberance  20 , which extends axially from the flange  18 .  
         [0022]    Referring to FIG. 3, a generally cylindrical closure  22  for closing the opening  17  (FIG. 2) of the container compartment  12  is depicted. Closure  22  has at least one second detent feature  24 , preferably two spaced notches, configured for interlocking with the first detent feature  20  in the flange  18  of container compartment  12 . Second detent feature  24  is preferably at least one notch formed in a peripheral end edge  26  for capturing the protuberance  20  in the flange  18  thereby securing the closure  22  from movement along the flange  18 .  
         [0023]    Referring to FIGS. 5 and 6, an alternative embodiment of the packaging container  10  (FIG. 1) of the invention is illustrated. According to FIG. 5, sidewalls  30  surrounding base  14  have a flange  18  and a first thread  36  extending helically at least partially around the sidewalls  16 . As in the previous embodiment, the flange  18  includes a first detent feature  38  extending axially therefrom.  
         [0024]    Referring to FIG. 6, a generally cylindrical closure  40  is configured for closing the opening  17 . Closure  40  has an inside second thread  42  extending helically about an inner wall  43  of closure  40  for cooperatively engaging the outside first thread  36  of container compartment  12 . A peripheral edge  44  of the closure  40  includes a second detent feature  46  for engaging the first detent feature  38  in the flange  18  thereby securing the closure  40  from axial movement along the flange  18 .  
         [0025]    In this embodiment, closure  40  can tightly close upon container compartment  12  by threadably screwing the first thread  36  into the second thread  42  so that the first detent feature  38  aligns with and then interlocks the second detent feature  46 . This prevents light penetration into the container compartment  12  and unintended unscrewing of the closure  40  after the closure  40  has been coupled through axial pressure with the container compartment  12 . Closure  40  may have a plurality of ribs  52  along its periphery for ease of engaging and disengaging the second thread  42  from the first thread  36 .  
         [0026]    As indicated above, the first detent feature  38  is preferably a protuberance having a generally arcuate shape. Skilled artisans will appreciate that the protuberance and the notch may have practically any shape such as a generally square shape, a generally V-shape or a generally C-shape. Depicted in FIG. 5, on either end of the generally arcuate shape protuberance  38  is a first land  54  and an opposed second land  56 . The first and second lands  54 ,  56  guide the protuberance  38  between an interlocking position and a free position relative to the second detent feature or notch  46 .  
         [0027]    In another embodiment of the invention, a method of forming a light-tight packaging container  10  for photosensitive film product includes the step of providing a packaging container  10  and a removable closure  22  configured to fit snugly about the container compartment  12 , each as described above. A first detent feature  20  is formed in the container compartment  12  by, for instance molding, and a second detent feature  24  configured for interlocking with the first detent feature  20  in a light-tight position is formed in the interior of the closure  22 . Once the detents  20 ,  24  are formed, the removable closure  22  is fitted on the container compartment  12  so that the first detent feature  20  interlocks with the second detent feature  24  in a light-tight relations.  
         [0028]    Packaging containers  10 , including the container compartment  12  and closure  22 , are preferably made of a rigid thermoplastic material, such as high density polyethylene. Those skilled in the art, however, will appreciate that other material compositions may be used, such as polystyrene or polypropylene.  
         [0029]    The invention has been described with reference to a preferred embodiment. However, it will 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  
       [0030]    [0030] 10  packaging container  
         [0031]    [0031] 12  container compartment  
         [0032]    [0032] 14  base of container compartment  12   
         [0033]    [0033] 16  sidewalls of container compartment  12   
         [0034]    [0034] 17  opening of the container compartment  12   
         [0035]    [0035] 18  flange  
         [0036]    [0036] 20  first detent feature or protuberance of flange  18   
         [0037]    [0037] 22  closure  
         [0038]    [0038] 24  second detent feature or notch of flange  18   
         [0039]    [0039] 26  peripheral end edge  
         [0040]    [0040] 30  sidewalls of alternative embodiment of packaging container  10   
         [0041]    [0041] 36  first thread  
         [0042]    [0042] 38  first detent feature or protuberance of alternative embodiment of packing container  10   
         [0043]    [0043] 40  closure of alternative embodiment  
         [0044]    [0044] 42  second thread  
         [0045]    [0045] 43  inner wall of closure  40   
         [0046]    [0046] 44  peripheral edge of closure  40   
         [0047]    [0047] 46  second detent feature or notch of alternative embodiment of packaging container  10   
         [0048]    [0048] 52  ribs in closure  
         [0049]    [0049] 54  first land  
         [0050]    [0050] 56  second land