Abstract:
A modular container for consumable products includes a first receptacle, defining a first volume, and a second receptacle, defining a second receptacle volume. Joining means for joining the first container and the second container has first and second sides and is adapted for positioning between the containers at the open ends. The joining means covers the open end of the second receptacle when placed in engagement with the second receptacle open end to form a sealed joint in a joining means combination. The joining means combination has a first attachment mechanism for removably attaching the combination to the open end of the first receptacle such that the joining member is interposed between the first and second receptacles.

Description:
FIELD OF THE INVENTION 
       [0001]    Generally, the invention includes insulated vessel technology, more specifically, sectional insulated vessels. 
       BACKGROUND OF THE INVENTION 
       [0002]    The origin of bento can be traced back to the late Kamakura Period (1185 to 1333), when cooked and dried rice called hoshi-ii (literally “dried meal”) was developed. Hoshi-ii can be eaten as is or boiled with water to make cooked rice, and is stored in a small bag. In the Azuchi-Momoyama Period (1568 to 1600), wooden lacquered boxes like those of today were produced and bento would be eaten during a hanami or a tea party. 
         [0003]    In the Taishō period (1912 to 1926), the aluminum bento box became popular as a luxury item because of its ease of cleaning and its silver-like appearance. Bento regained its popularity in the 1980s, with the help of the microwave oven and the proliferation of convenience stores. While, in convenience stores and at train station vendors, the expensive wood and metal boxes have been replaced with inexpensive, disposable polystyrene boxes, handmade bento in elaborate steel boxes have made a comeback. Bento boxes are still used by workers as a packed lunch, by families on day trips, for school picnics and sports days etc. 
         [0004]    In the tradition of the bento, there have flourished a number of insulated container devices for consumable products, such as thermos bottles and lunch boxes. Food containers with multiple compartments also exist. One trend in lunch boxes is represented by the lunch sack generally made of vinyl, with foam insulation, and an aluminum sputtered on vinyl interior. As a result, such lunch sacks usually much better than traditional bento at retaining their temperature but are less rigid and, thus, much less protective of the enclosed food. A distinct development has been the steel lunch box having rigid insulated walls that preserve the temperature of the food they contain. 
         [0005]    Efforts at placing the varied content of a lunch within a multiply chambered insulated vessel include U.S. Pat. No. 5,366,089 to Parker for a Separable Food and Beverage Container Combination. Parker describes one example of a separable container combination for food and beverages, but requires a large number of parts and does not provide for separation means between open ends of two containers in the container combination. Instead, the combination has the opposed end of one container adjoining the open end of the other container when the combination is attached together, thus requiring a separate cover piece for the second container. 
         [0006]    Another such effort is taught in U.S. Pat. No. 4,474,303 to Maccise for a Portable Modular Food Container. Maccise, like the U.S. Pat. No. 5,366,089 patent to Parker, requires a large number of parts and does not provide separation means between the open ends of the modular containers described in the patent. 
         [0007]    U.S. Pat. No. 4,496,068 to Blease demonstrates a Container Assembly which has only three main parts to form two separable containers, but, as in the devices disclosed in the above discussed patents, the opposed end of one container abuts the open end of the other container when the two containers are attached together. A cover for the second container is also exposed, making it easy to inadvertently loosen or remove. The cover for the second container is small in relation to the container itself, which makes the container difficult to clean and impedes access to the contents of the container if they are not a liquid with low viscosity. 
         [0008]    Therefore, a need exists for a multiply sectioned container system for enclosing consumable products wherein the system does not require a separate lid for each formed section. A further need exists for a sectioned container for consumable products adapted to receive products having differing volumes. 
       SUMMARY OF THE INVENTION 
       [0009]    By providing a modular container system for consumable products having at least first receptacle defining a first volume with an open end and a opposed end, a second receptacle defining a second volume with an open end and a opposed end, and a septum adapted for positioning between the receptacles at the open ends for separating contents of the first receptacle and the second receptacle. In a presently preferred embodiment, elements also known as modules of the modular system are formed of double-walled stainless steel wherein the volume between the double-walls has been evacuated to enhance insulating properties of the double-walled module. An alternative embodiment substitutes a polymeric material for the stainless steel to capitalize on the polymeric material&#39;s inherent properties allowing for ease of manufacturing and cleaning The a presently preferred embodiment includes rubberized grip surfaces on the exterior of the first and second receptacles, and cooperative series of threads so that the septum may be securely and removably attached to the second receptacle and the second receptacle and septum combination may be removably attached to the first receptacle. A presently preferred embodiment employs bayonet mounts rather than threads for positive engagement and to prevent cross-threading in use. The at the threads or bayonet mounts, modules may also include one or more annular fluid seals to prevent any fluid or partially fluid contents of the containers from leaking and to better maintain the freshness of non-fluid contents. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Preferred and alternative examples of the present invention are described in detail below with reference to the following drawings: 
           [0011]      FIG. 1  is a situational view of two embodiments of a modular insulated container system; 
           [0012]      FIG. 2  is a cross-sectional view of a first configuration of a first embodiment of the modular insulated container system; 
           [0013]      FIG. 3  is a cross-sectional view of the first configuration of the first embodiment of the modular insulated container system in a partially disassembled state; 
           [0014]      FIG. 4  is a cross-sectional view of a second configuration of the first embodiment of the of the modular insulated container system; 
           [0015]      FIG. 5  is a cross-sectional view of a third configuration of the first embodiment of the of the modular insulated container system; 
           [0016]      FIG. 6  is a cross-sectional view of the third configuration of the first embodiment of the of the modular insulated container system is a partially disassembled state; 
           [0017]      FIG. 7  is a cross-sectional view of a fourth configuration of the first embodiment of the of the modular insulated container system; 
           [0018]      FIG. 8  is a cross-sectional view of the fourth configuration of the first embodiment of the of the modular insulated container system in a partially disassembled state; 
           [0019]      FIG. 9  is a cross-sectional view of a fourth configuration of the first embodiment of the of the modular insulated container system employing adjoining septae; 
           [0020]      FIG. 10  is a cross-sectional view of a fifth configuration of the first embodiment of the of the modular insulated container system; 
           [0021]      FIG. 11  is a cross-sectional view of a sixth configuration of the first embodiment of the of the modular insulated container system; 
           [0022]      FIG. 12  is a cross-sectional view of a first configuration of the second embodiment of the of the modular insulated container system; 
           [0023]      FIG. 13  is a cross-sectional view of a second configuration of the second embodiment of the of the modular insulated container system; 
           [0024]      FIG. 14  is a cross-sectional view taken along line a of a third embodiment of the of the modular insulated container system; and 
           [0025]      FIG. 15  is a cross-sectional view taken along line a of a fourth embodiment of the of the modular insulated container system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]      FIG. 1  is a situational view of two embodiments of a modular insulated container system shown as used in a casual picnic at the Crissy Field Picnic Area. Portrayed in the tableau, a couple uses a first inventive embodiment generally  10  and a second inventive embodiment, generally  20 . The first embodiment  10  includes Dewar flask  11  having a septum base  13  and a utensil bin  12 . A tumbler  15  rests alongside the Dewar flask  11  and might alternatively be engaged atop the Dewar flask  11  when the first embodiment is transported, such as to a car in a parking lot. Cheese and crackers rest on a septum platter  22  alternatively used to top the second embodiment  20  when transported. Cups  17  with which the couple toasts the weather and utensils  19  resting on and alongside the septum platter  22  will nestingly store within the utensil bin  12  during transportation. 
         [0027]    The portrayed first and second embodiments  10 ,  20  are further advantaged by the wheeled caddy (not shown) that receives each of the embodiments on mounting pads affixed to a spine running between the spaced apart wheels and a handle. The mounting pads on the wheeled caddy engage the first and second embodiments in one of either of screwing or bayonet-style engagement for secure transportation with additional holding restraint during movement. The wheeled transport will foldingly stow in small spaces upon removal of the embodiments of the invention. Alternate embodiments of the wheeled cart may, optionally, include more than one pad for one or the other or both of the embodiments. Thus, the couple easily transported the embodiments across the parking lot and over the sand from the notoriously small boot in his vintage 1971 Jaguar XKE Series 3 V-12 to the beach where the couple is here portrayed. 
         [0028]    Referring, now, to  FIG. 2 , a study of a cross-sectional view of the first embodiment  10  reveals Dewar flask  11 , with a stopper  33  and septum  13  resting in screwing engagement with the utensil bin by joining a tube member  17  in screwing engagement to a base  31 . With these basic building blocks, the modular design of the invention is revealed. 
         [0029]    Modular design, or “modularity in design” is an approach that subdivides a system into smaller parts (modules) that can be independently created and then used in different systems to drive multiple functionalities. A modular system includes functional partitioning into discrete scalable, reusable modules consisting of isolated, self-contained functional elements with Rigorous use of well-defined modular interfaces. 
         [0030]    Besides reduction in cost (due to lesser customization, and less learning time), and flexibility in design, modularity offers other benefits such as augmentation (adding new solution by merely plugging in a new module), and exclusion. Modular design seeks to combine the advantages of standardization (high volume normally equals low manufacturing costs) with those of customization. 
         [0031]    A modular insulated container system, in accordance with the principles of the invention, then, is generally indicated at reference numeral  10 . In explanation of the modular nature of the invention, the key concept to grasp is that 
         [0032]    In each configuring any of the embodiments, there is one instance of joining one element to another. Referring to  FIGS. 3 ,  4 , and  5 , one of the strengths of the modular design of all of the embodiments is demonstrated to be in the flexibility the design enables. A stopper  33  and the Dewar flask  11  cooperate to define a first receptacle  42  which has a first receptacle open end  44  and a first receptacle opposed end  46  defining a first volume  48 . The tube member  17  cooperating with the base  31  forms a second receptacle  52  which has a second receptacle open end  54  and a second receptacle opposed end  56  defining a second volume  58 . The septum  13  with a first side  131  and a second side  132  is used to separate the first receptacle  42  from the second receptacle  52  and is interposed between the first receptacle open end  44  and the second receptacle open end  54 . 
         [0033]    In selecting the septum  13  to join the first receptacle  42  to the second receptacle  52 , the user has elected to form two distinct volumes, the first receptacle volume  48  and the second receptacle volume  58 . The insulated septum  13  having its first side  131  engages the first receptacle  42  at its first receptacle open end  44 , thereby completing the enclosure of the first receptacle volume  48  rendering it capable of insulatedly storing a food or beverage. The insulated septum  13  can, as is illustrated in  FIG. 2 , engage at the septum second side  132 , the tube member  17  cooperating with the base  31  to form the second receptacle volume  58 . Upon screwing engagement with the septum second side  132  at the second receptacle open end  54 , the tube member  17  insulatedly encloses the second receptacle volume  58 . As such it, too, can insulatedly store a food or beverage just as the first receptacle volume  48  can store a food or beverage without fear of changing the temperature of either food or beverage or of mixing them. 
         [0034]    As is shown in  FIG. 3 , access to the second receptacle volume is readily achieved by the disengaging of the septum second side  132  from the second receptacle open end  54 . While illustrated in drawings as a threaded engagement, the presently preferred engagement is a bayonet mount. Either, however, will well serve the object of the invention. Wherever within this application, the verb or adjective “screwing” is used, it is the intent of the applicant to encompass, alternatively, “engaging a bayonet mount” as the context might indicate. 
         [0035]    A bayonet mount or bayonet connector is a fastening mechanism consisting of a male probe with one or more pins, and a female receptor with matching L slots and spring or springs to keep the two parts locked together. To couple the male probe with the female receptor, the pin or pins on the male probe are aligned with the slot or slots on the female receptor and the two pushed together. Once the pins reach the bottom of the slot, the two receptor and probe are turned in opposite directions to guide the pin across the bottom of the L shaped slot. The spring or springs then hold the pin in position to prevent it from backing out. To disconnect, the probe and receptor are pushed together to overcome the spring whilst twisting slightly to reverse the locking turn. 
         [0036]    The strength of the joint relies on the shear strength of the pins and the strength of the L slots which hold the pins in place when locked. A practiced user can connect them quickly and they are not subject to cross-threading. For this reason, in the presently preferred embodiment, the septum second side  132  can be manually removed from the second receptacle open end  54  by a user&#39;s thumb and index finger. 
         [0037]      FIG. 3  shows the second receptacle  52  removed from the first receptacle  42  and resting on a flat surface with the second receptacle open end  54  facing up for easy access to food or beverages such as salad dressing which may be contained therein. As illustrated in  FIG. 1 , the formed utensil bin  12  may be used to stow the individual utensils  19  and cups  17  for the picnic, so the utility of the modular system is not strictly limited to food alone. 
         [0038]    By selective use of modular components, the system enables two distinct relationships between the first receptacle volume  44  to the second receptacle volume  54  as that relationship is defined by either of the intervening septum  13  or the connector  23 . When used with the connector, the first receptacle volume  44  is conjoined with the second receptacle volume  54 . In still another configuration, the first receptacle volume may simply be enclosed by engagement between the first receptacle  42  and the base  31 . 
         [0039]    Shown as well in  FIG. 4  is the connector  23  which in appearance and in use is very similar to that of the septum  13  in that the connector  23 , at its first side  231 , also engages the first receptacle  42  at its first receptacle open end  44 , but is distinct as the connector  23  does not complete the enclosure of the first receptacle volume  48 . To render the first receptacle  42  capable of insulatedly storing a food or beverage, the second receptacle  52 , at its second receptacle open end, engages the connector  23 , at its second connector side  232  to the second receptacle volume  58 . Upon such engagement, a connector communicating volume  238 , provides an interstitial volume to communicate between the first receptacle volume  44  and the second receptacle volume. As such, the so-configured modular system  10  can perform as any double-walled bottle such as those sold under the Thermos™ Stainless King Beverage Bottle™ or the Stanley™ Classic Stainless Steel Vacuum Bottle. 
         [0040]      FIGS. 5 and 6  demonstrate the flexibility of the system. Consider a user&#39;s desire to bring diverse foods such as chili and pudding to school for lunch. As the foods that user selected must both be insulated from the ambient and from each other, they must be contained in distinct volumes. To that end solutions such as the Zojirushi™ Mr. Bento Stainless Steel Lunch Jar™, a single double-walled wide-mouthed stainless steel vacuum jar enclosing individual polymeric containers will not meet the user&#39;s need. The configuration of the modular system  10  shown in  FIGS. 5 and 6 , will, however. 
         [0041]    On again, the so-configured system  10  defines the first receptacle  42  using a first tube member  17  connected to the septum  13  and enclosed at the first receptacle opposed end  46  by threaded engagement with a lid  32 . The first receptacle  42  enclosates the first receptacle volume  48  generally contained in the first tube member  17 . The elements of the lid  32 , the first tube member  17  and the septum  13  cooperate to form the first receptacle and when form serve to keep the temperature within the first receptacle volume  48  at a constant level to maintain the freshness and crispness of the exemplary food item, pudding with fruit inclusions. 
         [0042]    A second receptacle  52  is defined, in cooperation with the septum  13 , by the second tube member  17  in engagement with the base  31 . Just as the first tube member  17  encompasses the first receptacle volume  42 , the second tube member  17  encompasses the second receptacle volume  52  and, likewise, keeps that volume  52  insulated from the ambient and from the first receptacle volume  42 . Thus, in the example, the piping hot chili, the second receptacle volume  52 , remains piping hot without heating the pudding within the first receptacle volume  42 . 
         [0043]      FIG. 6  shows the first receptacle  42  and the second receptacle  52 , each open to the ambient for access. As is evident from comparison of  FIGS. 5 and 6 , access to the first receptacle volume  48  is achieved by separation of the first tube member  17  from the lid  31 , while access to the second receptacle volume  58  is achieved by separating the second tube member  17  from the septum  13 , while the septum  13  remains engaged to the first tube member  17  to contain the first receptacle volume  48 . 
         [0044]    Continuing then, to  FIGS. 7 and 8 , As is evident in the foregoing explanation, the modular system in every embodiment includes at least one of a tube member  17  or Dewar flask  11  with either of threaded or bayonet mount engagement with one of a stopper  33 , a lid  32 , a septum  13 , or a connector  12 . As must also be evident, nothing limits the embodiment to a first receptacle  42  joining a second receptacle  52 . Indeed, the septum  13  could further join another tube member  17  and a base  31  forming a third receptacle  62  enclosing a third receptacle volume  68  and likewise stack still further receptacles to contain such a diversity of foods, beverages, or utensils, as a user might need. As illustrated, utensils  19  might be contained in one of the receptacle volumes such as in the second receptacle volume  58 . A beverage might reside in the first receptacle volume  48 , advantageously defined by a Dewar flask  11  rather than a tube member  17 , and hot food is contained in the third receptacle volume  68 , the third receptacle  62  defines. 
         [0045]      FIG. 9  portrays a variation on the embodiment shown in  FIG. 7 . Rather than to use the septum  13  that provides a bottom to contain the first receptacle volume  48 , a second septum  13  is used. Thus, distinct septae  13  are used allowing the first receptacle  42  to separate from the second receptacle  62  without exposing either of the first receptacle volume  48  or the second receptacle volume  68  to the ambient. Such a user-selected configuration prevents the introduction of contaminants, such as sand at a beach, when the first receptacle is set down on, for example, a beach blanket. Thus, where the septum  13  attached to the first receptacle  42  serves as a base, the septum  13  does not draw sand into the second receptacle  62  when the receptacles are rejoined. Ring members  17   d  and  17   g  in  FIGS. 14 and 15 , infra, also serve the same function of allowing two septae  13   a,    13   b  to join, protecting the contents of the second receptacle  62 . 
         [0046]    A strength of the modular system is its ability to meet the needs of the user. When used with the wheeled cart described above, a plurality of modules could bring a feast of divergent foods to a location with a minimum of effort. 
         [0047]    The further exploitation of modular elements in various configurations meets a variety of user needs. For example, in  FIGS. 10 and 11 , to shelter and insulate a glass wine bottle  91  and two glass wineglasses  92 , tube members  17  are configured with other elements to form transportable cases. For the wine bottle  91 , two tube members  17  are joined by engagement to the connector as earlier described. The lid  32  and the base  31  join to form an outer shell  33   a.  Addition of a first compressible formed liner  34   a  (by way of nonlimiting example, a neoprene liner), and a second compressible formed liner  34   b  complete the case. 
         [0048]    Modifying the first outer shell  33   a  by substituting the septum  13  for the connector  23  forms the second outer shell  33   b.  Placing a third formed liner  33   c  in each of the resulting enclosed volumes, the case is suitable for transportation of the wineglasses  92  with minimal risk of breakage. 
         [0049]    While the diameter of the foregoing examples has been suggestive of single embodiment of roughly the same dimensions as the Thermos™ Stainless King Beverage Bottle™ or the Stanley™ Classic Stainless Steel Vacuum Bottle, nothing in the nature of the invention limits the diameter. By way of demonstration,  FIGS. 12 and 13  show a 12″ embodiment of the modular system showing the system&#39;s ability to mimic the functionality of a pie safe, a cooler, and a spigoted jug. 
         [0050]    As noted several places in the discourse above, the engagement between the tube member  17  and the several modular elements is shown to be threaded engagement for ease of illustration and understanding but in the presently preferred embodiment bayonet mount engagement achieves the structurally rigid sealing union between the tube member  17  and the sundry elements. While not shown, the sealing union in a presently preferred embodiment includes a conventional, food grade O-ring seated on a peripheral rim on each modular element as appropriate to assure a liquid tight seal. 
         [0051]      FIGS. 12 and 13  show two configurations of an embodiment having a 12 inch diameter. As stated above, the versatility of the modular system  20  and the range of suitable dimensions allow the use, as shown in  FIG. 11 , of a first receptacle volume  48   a  defined, in part by the lid  32   a  and the septum platter  22  as a pie safe. A second receptacle space  58   a  defined in part by the two portrayed septum platters  22  serves as a cooler containing, for example, canned beverages  95 , wrapped product such as cheese  94 , and polymeric containers  96  such as those by Tupperware™, and all are cooled by the presence of ice  99 . In a third receptacle space, partially defined by the second septum platter  22  and the base  31   a,  a slightly modified tube member  17   b  includes a spigot  88  allowing the space to contain a liquid beverage such as lemonade  97  cooled, again, by the presence of ice  99 . 
         [0052]    Comparing  FIGS. 12 and 13 , the modular system, again, shows its versatility. In substituting a connector member  23   a,  the user allows a greater volume of the lemonade (in this nonlimiting example) to fill both of the second receptacle space  58   a  and the third receptacle space  68   a  as those spaces are joined by the communication the connector  23   a  enables. The first receptacle space  48   a  now serves as the cooler that had, in  FIG. 11 , occupied the second receptacle space  58   a.    
         [0053]    While the foregoing discussion sets forth the presently preferred embodiment, the threading scheme as to which elements will bear a “male” or a “female” configuration. In electrical and mechanical trades and manufacturing, each half of a pair of mating connectors or fasteners is conventionally assigned the designation male or female. The “female” connector is generally a receptacle that receives and holds the “male” connector. Referring then, to  FIGS. 14 and 15 , in the foregoing discussion, the lid  32   a  has been suggested to have a female threading at its open end. In  FIG. 14 , however, the lid  32  is shown in an equally facile embodiment with the threading on the outside of the peripheral rim rather than the inside as in the lid  32   a  ( FIG. 13 ). As might be evident in this discussion, the nature of the various embodiments is determined, generally, by the threading combinations (remembering that “threading” is defined herein as including, as well, bayonet mounting, a manner of engagement to which the “male” and “female” descriptors apply with equal vigor.) that occur on the tube member  17  generally. In the preceding description, the tube member  17  has been described in its preferred embodiment having both a male and a female engagement at opposed ends of the tubular member  17  generally. 
         [0054]      FIG. 14  portrays a tube member  17   c  with two male thread sets on opposed ends. Selection of male threads on the tube member drives the selection of female threads on each of the possible engaging surfaces on any of the joining members, a group comprising such as the lid  32   a,  the connector  23   a,  the septum  13   a,  and the base  31   a.  Likewise, the Dewar flask (not shown) must share the same threading pattern as the tube member  17   c,  in order to engage each of the joining members, the lid  32   a,  the connector  23   a,  the septum  13   a,  and the base  31   a.  In such a manner, the alternate embodiment performs with equal facility as the preferred embodiment. To further accommodate the use of this embodiment, a shortened tube member  17   c  called a ring member  17   d  is used as a “gender changer” allowing septae  13   a  to be joined to create distinct first and second receptacles. 
         [0055]    Also notable is the variant on the lid  32   a  as characteristic of the nature of the disclosure the specification comprises. While the discussion has focused upon the engagement between modular elements, variants of each of the elements are possible, such as the addition of a handle  82  to the lid  32   a  while remaining entirely within the spirit of the disclosure. Handles and rubberized grip surfaces do not modify the basic intent of the invention, but are known to persons having ordinary skill in the art as details that amplify the utility of the invention. Likewise, in  FIG. 15 , the tube member  17   d  is modified with a handle  87  the does not diminish the scope of the disclosure, rather, such variants are included within this disclosure by this reference. In a like manner, nothing within this disclosure limits it to practice in the context of stainless steel embodiments. Any suitable material such as polymeric plastics and alternate metals are also encompassed with the practice of the invention. 
         [0056]    Just as the system  20  as portrayed in  FIG. 14  is defined by the inclusion of two male engagements on the tube member  17   c,  the system  20  can be practiced with equal facility as is defined by a tube member having female engagements on opposed ends (and on the open end of the Dewar flask (not shown)) as in  FIG. 15 . Also just as the system  20  depicted in  FIG. 13  is defined by the male threading on the tube member  17   c,  in the system  20  of  FIG. 14 , joining members, including the lid  32   b,  the connector  23   b,  the septum  13   b,  and the base  31   b  must have male engagement surfaces, as depicted, to suitably fulfill their roles in the modular system. The “gender” changer or ring member  17   g  is a shortened tube member  17   f.    
         [0057]    While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. For example, the container  10  could be made of stainless steel or other materials rather than a polymeric material; the insulated volumes could be evacuated rather than being air-filled, or alternatively foam filled; other attachment means such as cam lock latches could be used to removably attach the septum  13  to the tube member  17  rather than using two cooperative series of threads  56 ,  58 ; other attachment means could also be used to removably attach the tube member  17  to the septum  13  or connector  23  rather than using two cooperative series of threads; the exterior of the system  10  could be a different shape; and different gripping means such as handles or raised knobs could be used as gripping surfaces on the tube member  17 . Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.