Abstract:
A sealing assembly is provided for creating an airtight seal between a container and a piece of film, A bladder is inflated, which puts upward pressure on a base plate of a Lift assembly. The lift assembly includes downwardly extending arms, and as the base plate is lifted by the inflating bladder, the lift arms lift the container and film into contact or near-contact with a heater plate to seal the film to the container. Deflation of the bladder allows the lift assembly to lower thereby lowering the now-sealed container.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority to and incorporates herein by reference U.S. Provisional Patent Application Ser. No. 61/503,792 filed on Jul. 1, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to an apparatus for sealing containers and, more particularly, to an apparatus for heat-sealing a laminate film onto a container for storing food therein. 
       BACKGROUND OF THE INVENTION 
       [0003]    Various techniques have been used by consumers for storing food and beverages in containers. Some containers use re-sealable lids which may screw or snap onto the container to store foods. Some containers take the form of so-called zipper-top storage bags. However, the sealing ability of such containers is questionable, as leaks often occur. Further, the seal between containers and their closure mechanisms are often gas permeable, allowing the food inside to spoil. 
         [0004]    Large companies often use industrial sealing devices that can create an airtight seal between a disposable container and a film that covers the container. However, such technology has been generally unavailable to consumers. As a result, there is a need for a low cost, fully automatic sealing apparatus capable of providing an airtight seal between a container and film which covers a container. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention includes a sealing apparatus for sealing a laminate film onto a container. The sealing apparatus includes a bottom housing assembly which may include a drawer which is selectively extendable outwardly from the bottom housing via rails. The bottom housing preferably also includes a container support for holding a container in place. Preferably, the container support also includes a film roll support for supporting a roll of film, and allowing the same to be pulled across the open top of a container which is held by the container support. A film cutter may also be included on the container support for cutting the film from the roll. The film is preferably a laminate film with a non-stick top layer and a bottom layer designed to be sticky when melted. The top layer preferably remains non-stick and unmelted at a temperature at which the bottom layer begins to melt. More preferably, the top layer includes polyester while the bottom layer includes polyethylene. 
         [0006]    The present sealing apparatus also includes a lid assembly which is preferably hingedly attached to the bottom assembly for pivoting the lid assembly between an open and closed position with respect to the bottom housing. The lid assembly preferably includes a lift assembly haying a base plate and lift arms for lifting the container support. A bladder is preferably located under the base of the lift assembly, and may be inflated by a bladder pump to lift the lift assembly. The bladder pump is preferably controlled by a microcontroller which detects the pressure within the bladder. The microcontroller may also detect other variables such as the distance traveled by the lift assembly as it is lifted or lowered by the bladder. The lid assembly also preferably contains a heater plate. 
         [0007]    In operation, the drawer is pulled at least partially out of the bottom assembly, and a container is placed in the container support. A food or beverage is placed in the container, and film from the film roll which is rotatably mounted on the film roll support is extended up and over the top of the container. The container support may have pads associated therewith which help hold the film temporarily in place. The drawer is then slid back into the bottom assembly. 
         [0008]    The lift arms of the lift assembly are preferably angled inwardly toward the bottom end of the lift arms. As the drawer containing the container in the container support slides back into the bottom assembly, the left and right sides of the container support slide in horizontally above the inwardly angled portions of the lift arms. The lift arms thereby extend down past the at least a portion of the sides of the container support such as a top edge portion, and the lift arms curve under the same to engage therewith. Alternatively, flanges may extend from the sides of the container support, and the lift arms may engage these flanges. 
         [0009]    Upon activation, the heater plate in the lid assembly heats to a desired temperature. Once pre-heated, the bladder pump inflates the bladder. As the bladder inflates, it puts upward pressure on the base plate of the lift assembly, lifting the lift assembly upward. As the lift assembly is lifted, the lift arms are also lifted. Since the lift arms extend down past and under at least a portion of the sides of the container support, the lift assembly thereby lifts the container support (and the container with the film across its top) upwardly until the film comes in contact with the heater plate. The heater plate heats the film to a temperature at which the bottom layer of the film begins to melt and adheres to the container. The top layer of the film, however, remains non-stick and unmelted so that the film does not also stick to the heater plate. 
         [0010]    Once the film has adhered to the container, the bladder is deflated, allowing the lift assembly to lower the container support back into place. As the lower layer of the film cools, it solidifies and forms an airtight bond with the container. The film which is adhered to the container may thereafter be cut from the film roll manually, or it may have been automatically cut previously, such as by a wire cutter in the lid assembly during the heating of the film by the heater plate. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of one embodiment of a sealing apparatus constructed according to the teachings of the present invention. 
           [0012]      FIG. 2  is an exploded perspective view of the sealing apparatus of  FIG. 1 . 
           [0013]      FIG. 3  is a side cress-sectional elevation view of the sealing apparatus of  FIG. 1  in its lowered or “off” position. 
           [0014]      FIG. 4  is a side cross-sectional elevation view of the sealing apparatus of  FIG. 1  in its raised or “sealing” position. 
           [0015]      FIG. 5  is a perspective view of a container held in the container support according to the teachings of the present invention. 
           [0016]      FIG. 6  is a perspective view of a smaller container held in the container support as modified with a small container support member according to the teachings of the present invention. 
           [0017]      FIG. 7  is a perspective view of the sealing apparatus of  FIG. 1  in an open position. 
           [0018]      FIG. 8A  is a side cross-sectional view of another embodiment of a sealing apparatus according to the present invention, in its raised or “off” position. 
           [0019]      FIG. 8B  is a side cross-sectional view of the sealing apparatus of  FIG. 8A  in its lowered or “on” position. 
       
    
    
       [0020]    It should be understood that the present drawings are not necessarily to scale and that the embodiments disclosed herein are sometimes illustrated by fragmentary views. In certain instances, details which are not necessary for an. understanding of the present invention or which render other details difficult to perceive may have been omitted. It should also be understood that the invention is not necessarily limited to the particular embodiments illustrated herein. Like numbers utilized throughout the various figures designate like or similar parts or structure. 
       DETAILED DESCRIPTION 
       [0021]    Referring now to the drawings and, more particularly, to  FIG. 1 , a sealing apparatus  1  constructed according to the teachings of one embodiment of the present invention is shown including a lid assembly  2  and a bottom housing assembly  4 . The lid assembly  2  includes base control panel  6 , while the bottom housing assembly  4  includes a power cord  8 , a drawer  10  and a locking member  12 . Control panel  6  may include at least one button, LED indicator light, lever, knob, a display screen, a touch screen, or any other suitable structure for turning the sealing apparatus  1  on and/or indicating its status. As can be seen in  FIG. 7 , lid assembly  2  and bottom housing assembly  4  are preferably hingedly connected to one another toward the back of the sealing apparatus  1 . Alternatively, lid assembly  2  and bottom housing assembly  4  may be hingedly connected at a different location, or may be permanently connected, or may be selectively disengageable from one another. Locking member  12  is preferably operable to prevent the lid assembly  2  from being opened or disengaged from the bottom housing assembly  4  during operation of the sealing apparatus  1  as discussed in detail below. 
         [0022]    As can be seen in  FIG. 2 , bottom housing assembly  4  includes rails  14  which allow drawer  10  to selectively slide at least partially out from the front of bottom housing assembly  4 . Drawer  10  is preferably sized and shaped to receive and support a container support  16 . Container support  16  preferably includes support member  18  which is designed to receive and support a container  24 . Container support  16  preferably also includes film roll support  20  for holding a roll of film (not shown), one or more pads  22  for temporarily helping to hold the film in place at the front of the container support  16  once it has been extended over the container  24  before sealing, and a film retainer member  26  for holding the film in place at the back of the container support  16 . Film roll support  20  may include opposing support brackets between which a roll of film can be positioned for rotatable support. 
         [0023]    In operation, a user pulls drawer  10  out from bottom housing assembly  4 . Container support  16  rests within drawer  10  such that withdrawing drawer  10  also causes container support  16  to be withdrawn from bottom housing assembly  4 . The user then places food or beverage in a container  24 , and places the container  24  into container support  16 . The user then pulls a layer of film from the roll of film supported by film roll support  20  at the rear of the container support  16 , and extends the layer of film over top of the container  24 . As noted above, container support  16  may include pads  22 , which are preferably made of a material which temporarily assists in retaining the film in place upon contact between the film and the pads  22 . The user then pushes the drawer  10  (and container support  16  and container  24 ) back into bottom housing assembly  4 . 
         [0024]    As can be seen in  FIGS. 3 and 4 , the lid assembly  2  of sealing apparatus  1  includes a bladder  30  positioned below a lift assembly  32 . A pump  34  is in fluid communication with bladder  30  to inflate bladder  30 . Lift assembly  32  includes at least one lift arm  36 , and preferably a plurality of lift arms such as the six lift arms  36  shown in  FIGS. 3 and 4 . The top end of lift arm  36  is preferably connected to a base plate of lift assembly  32 . Further, each lift arm  36  preferably extends downwardly and, at its lower end, engages with the container support  16  to lift container support  16 . More preferably, the lower end of each lift arm  36  extends under at least a portion of container support  16  or a flange thereon to lift container support  16 . At least one lift guide post  38  is also provided in lid assembly  2 , as well as a heater plate  40  and a controller  42 . Controller  42  is preferably in electrical communication with heater plate  40 , pump  34  and control panel  6 . 
         [0025]    In operation, a container  24  is placed in container support  16  and film is extended over container  24 . Once the drawer  10  is closed, container  24  and container support  16  reside within the sealing apparatus  1 . While inside bottom housing assembly  4 , at least a portion of container support  16  is positioned above the lower end of at least one lift arm  36 , such that the lower end of at least one lift arm  36  extends under a portion of container support  16 . A cutoff may prevent the sealing apparatus  1  from energizing when the drawer  10  is open and/or when lid assembly  2  is open. 
         [0026]    A user can then activate the sealing apparatus  1  via control panel  6 . Controller  42  then causes pump  34  to inflate bladder  30 . The inflation of bladder  30  causes the bladder  30  to press upwardly on the base plate of lift assembly  32 , thereby raising lift assembly  32 . Lift assembly  32  is guided so as to lift substantially vertically by at least one lift guide post  38 .  FIG. 3  illustrates the sealing apparatus  1  in its “off” or “lowered” position, while  FIG. 4  illustrates the sealing apparatus  1  in its “on” or “raised” or “sealing” position.  FIG. 3  illustrates three lift arms  36  positioned on the far side of container support  16  such that the container support blocks the view of much of lift is  36 .  FIG. 4  illustrates three lift arms  36  positioned on the near side of container support  16  such that the lift arms  36  in  FIG. 4  are more visible than those shown in  FIG. 3 . However, it will be understood that a plurality of far and near lift arms  36  may be included in the same sealing apparatus  1 , as needed or desired. 
         [0027]    As lift assembly  32  raises, the at least one lift arm  36  engages with container support  16  and simultaneously lifts the container support  16  as shown in  FIG. 4 . The container support  16 , and thereby container  24  with a layer of film thereon, are brought into proximity with heater plate  40  such that the heat from heater plate  40  causes the film to bond with container  24 . Proximity with the heater plate  40  may be direct contact with heater plate  40  such that container  24  presses the film thereover onto heater pad  40 . Alternatively, heater pad  40  may produce enough radiant heat to cause the film to bond with or seal to container  24  without direct physical contact therebetween. 
         [0028]    Preferably, heater plate  40  is pre-heated prior to the activation of pump  34  by the activation of at least one rope heater (not shown) by controller  42 . Alternatively, a mica heater, a CalRod® heater, a film heater, or other suitable heater may be used. Controller  42  preferably monitors at least one of the pressure within bladder  32 , the position of lift assembly  32 , and the position of container support  16 , and can cause further inflation or deflation of bladder  30  based thereon to effectuate proper sealing of the film to container  24 . A pressure sensor and/or one or more position sensors may supply pressure and/or position information to the controller  42  for monitoring of same. Sealing apparatus  1  may have more than one setting by which the user may adjust features such as the heater plate  40  temperature, the sealing time, and/or the pressure between the container  24 , the film and heater plate  40 . 
         [0029]    After sealing has occurred, the controller  42  causes the bladder  30  to deflate, thereby allowing the lift assembly  32  and container support  16  to lower back into their “off” positions. A user may then at least partially withdraw drawer  10  from bottom housing assembly  4  and remove the sealed container  24  therefrom. 
         [0030]    The film is preferably a laminated film comprised of at least two layers, but this is not meant to be limiting, as other films or a paper layer may be used. A bottom layer of the laminated film is designed to seal with or bond to the container  24 , and is therefore preferably composed of a material that will at least partially melt at a temperature produced by heater plate  40 . In an example embodiment, the bottom layer is polyethylene. A top layer is designed so as not to seal or bond to the heater plate  40 , and is therefore composed of a material that will not melt when heated to the temperature at which the bottom layer melts. In an example embodiment, the top layer is polyester. Additional layers may also be incorporated into the film. 
         [0031]      FIG. 5  illustrates an example embodiment of container support  16  and a standard sized container  24 . However, different sized containers may be used. For example, as shown in  FIG. 6 , a small container  25  is housed within container support  16 . in order to properly support the small container  25 , a selectively removable small container support  28  may be added to the container support  16  for engagement therewith. Small container support  28  may include its own tabs  22 . Adding the small container support  28  creates a smaller area into which container support  16  may receive a container  24 ,  25 . 
         [0032]      FIG. 7  illustrates an embodiment of a sealing apparatus  1  in which lid assembly  2  has been hingedly opened with respect to bottom housing. assembly  4 . This open position may allow for cleaning of the inside of sealing apparatus  1 . As noted above, locking member  12  is preferably operable to prevent the lid assembly  2  from being opened or disengaged from the bottom housing assembly  4 , and/or from preventing drawer  10  from being opened, such as during operation of the sealing apparatus  1 , as discussed above.  FIG. 7  also illustrates a heated wire cutter  44  which may be used to cut the piece of film used to seal a container  24 ,  25  from the roll of film. Other methods for cutting the film from the roll may also be employed, as would be understood by one of ordinary skill in the art. 
         [0033]    In another embodiment illustrated in  FIGS. 8A and 8B , the heater plate  140  may be slidingly mounted on a plurality of vertical posts  138  which extend downward from lid assembly  2 . Heater plate  140  may be movable between “raised” and “lowered” positions. In such an embodiment, the heater plate  140  is preferably biased into the “raised” position using springs and the like (not shown). The heater plate  140  may then be urged into the “lowered” position by inflation of the bladder  130 . As the container support  16  and container  24  are not lifted toward the heater pad  140  in this embodiment, the lift assembly  32  and lift arms  36  of the previous embodiment may be eliminated. In operation, the container  24  is placed in a container support  16  that rests within drawer  10 . Once the drawer  10  is closed, container  24  and container support  16  reside below the heater plate  140 . Since the heater plate  140  is biased toward the “raised” position, the heater plate  140  is not initially in proximity with the film extended over the container  24 , as shown in  FIG. 8A . A user can then activate the device with control panel  6 . 
         [0034]    Controller  142  then causes pump  134  to inflate bladder  130 . The inflation of bladder  130  causes the bladder  130  to press downwardly on heater plate  140  causing heater plate  140  to come into proximity with the film extended over the container  24 . The heater plate  140  is brought into proximity with the film such that the heater plate  140  causes the film to bond with the container  24 , as shown in  FIG. 8B . The operation of the heater plate  140  and pump  134  by controller  142  is described above in the previous embodiment. After sealing has occurred, the controller  142  causes the bladder  130  to deflate, thereby allowing the heater plate  140  to move back to the “raised” position. 
         [0035]    Thus, there has been shown and described several embodiments of a novel sealing apparatus. 
         [0036]    As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present invention will, however, become apparent to those skilled in the art after considering the specification and the accompanying drawings. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.