Abstract:
A container according to a preferred embodiment of the present invention provides an inner wall and an outer wall wrapped therearound so as to define a double-wall container construction. A plurality of spacer elements are interposed between the inner and the outer walls so as to maintain a minimum thickness of an air space defined therebetween.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field of the Invention 
         [0002]    The present invention relates to thermally insulated containers for storing beverages, and more particularly, for storing hot beverages such as coffee, tea and cocoa. More particularly, the present invention relates to thermally insulated containers for storing beverages, wherein the container is provided with a double wall construction, and wherein internal spacer elements are provided to maintain a minimum distance between the individual walls of the double wall construction. 
         [0003]    2. Brief Description of the Related Art 
         [0004]    Common single-use coffee cups are primarily made of paperboard or polystyrene. It is well known that the thermal insulation characteristics of polystyrene cups are far superior to those of either kraft paper or bleached paperboard cups. When a hot beverage, such as coffee, tea or cocoa, is poured into a single-use cup, the cup surface temperature rises to a maximum in a few seconds, then slowly cools with the beverage back to ambient temperature. If the maximum cup surface temperature exceeds about 140 degrees F., it is painful for an individual to hold the cup. The surface of a common polystyrene cup, nominally 0.090 in. thick, does not reach this threshold, but that of any single paperboard cup almost always exceeds it. 
         [0005]    It is well known to employ various sleeve designs for cups which emphasize insulation capabilities. Exemplary of such sleeves are U.S. Pat. No. 5,205,473 (&#39;473) to D. W. Coffin, Sr., entitled “Recyclable Corrugated Beverage Container and Holder,” U.S. Pat. No. 5,425,497 (&#39;497) to J. Sorensen, entitled “Cup Holder,” U.S. Pat. No. 5,667,135 (&#39;135) to R. J. Schaefer, entitled “Thermal Insulating Sleeve for Drink Cups,” U.S. Pat. No. 5,746,372 (&#39;372) to O. Spence, entitled “Biodegradable Cup Holder,” U.S. Pat. No. 5,794,843 (&#39;843) to R. S. Sanchez, entitled “Cup Wrap,” U.S. Pat. No. 5,826,786 (&#39;786) to J. Dickert, entitled “Cup Holder Sleeve in Pre-Assembled Flat-Folded Form,” and U.S. Pat. No. 5,842,633 (&#39;633) to R. I. Nurse, entitled “Sleeve for Beverage Cups.” While these references disclose various sleeves for use on beverage containers, none of these are particularly quantitative on the sleeve characteristics needed for good insulation. 
         [0006]    It is also known to employ cup designs that emphasize insulation. Exemplary of such cup designs are U.S. Pat. No. 4,007,670 (&#39;670) to J. V. Albano et al., entitled “Insulated Container,” U.S. Pat. No. 4,261,501 (&#39;501) to J. B. Watkins et al., entitled “Laminated Insulated Hot Drink Cup,” U.S. Pat. No. 4,435,344 (&#39;344) to A. lioka, entitled “Method for Producing a Heat-Insulating Paper Container From a Paper Coated or Laminated With a Thermoplastic Synthetic Resin Film,” U.S. Pat. No. 5,145,107 (&#39;107) to V. K. Silver et al., entitled “Insulated Paper Cup,” U.S. Pat. No. 5,226,585 (&#39;585) to R. Varano, entitled “Disposable Biodegradable Insulated Container and Method for Making,” U.S. Pat. No. 5,460,323 (&#39;323) to J. H. Titus, entitled “Disposable Insulated Container,” U.S. Pat. No. 5,542,599 (&#39;599) to R. E. Sobol, entitled “Biodegradable Thermally Insulated Beverage Cup,” U.S. Pat. No. 5,628,453 (&#39;453) to D. M. MacLaughlin, entitled “Cup With Thermally Insulated Side Wall,” U.S. Pat. No. 5,697,550 (&#39;550) to R. Varano et al., entitled “Multi-Layered Insulated Cup Formed From Folded Sheet,” U.S. Pat. No. 5,713,512 (&#39;512) to R. K. Barrett, entitled “Polymeric Insulated Container,” U.S. Pat. No. 5,752,653 (&#39;653) to M. Razzaghi, entitled “Paper Cup With Air Insulation,” U.S. Pat. No. 5,775,577 (&#39;577) to J. H. Titus, entitled “Disposable Insulated Container With Microflute Structure,” and U.S. Pat. No. 5,839,653 (&#39;653) to R. B. Zadravetz, entitled “Container With Corrugated Wall.” While a number of these references identify the effectiveness of an air gap and the providing of good insulation properties, they do not incorporate the simplicity of a sleeve cut from a single blank, add an air gap which is constructed of hot-melt glue dots, and employ a smooth outside-sleeve surface for printing. 
         [0007]    It is apparent from the above that there exists a need in the art for a sleeve construction which is lightweight through simplicity of parts and uniqueness of structure, but which incorporates a sleeve cut from a single blank, adds an air-gap layer, and preserves a smooth outside-sleeve surface for printing. It is the purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure. 
         [0008]    U.S. Pat. No. 6,152,363 (&#39;363) to J. A. Rule, entitled “Sleeve Construction for Improved Paperboard Cup Insulation,” teaches a beverage container sleeve construction which employs a matrix of hot-melt glue dots printed on one surface thereof for the purpose of maintaining a preselected distance between the sleeve and a complimentary beverage cup, around which the sleeve is wrapped. According to such a construction, the glue dots (and not the paperboard sleeve onto which the dots are printed) contact the outer surface of the cup, thereby defining an air gap between the sleeve and the cup such that a user&#39;s fingers gripping the sleeve will not be burned by the cup. However, there remains a need to improve upon an overall container construction incorporating such a technique for maintaining an air gap between complimentary walls of a double-wall beverage container. 
         [0009]    Single layer paper cup technology does not have the ability to keep beverages or drinks warm, and at the same time protect the hand from becoming uncomfortable from holding a hot liquid or material. Similarly, a simple single layer cup or container construction does not have the ability to insulate a cold beverage or product and protect the exterior of the cold container from moisture condensation that can pool on the bottom of the container and stain furniture or the interior finish of cars and vehicles. 
         [0010]    Many past container products have used very expensive solutions, such as an insulated foam laminate or a corrugated paper spacer to create cup sidewall thickness and this attempt to create hand-hold protection, in addition to heat- and cold-retention in the beverage or food product contained therein. All of the built-up laminated approaches to producing a thick-walled insulated cup require very unique and expensive converting equipment to manufacture a blank used to form the cup, plus an additional piece of equipment to wrap the resulting blank into a cup or container. A more simplified and high-speed system is required that could replace the high cost of a specialty blank converting manufacturing system. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention involves, among other things, the manufacture of an insulated cup by using a very small number of spacer elements (e.g., dots) that are printed, sprayed, laminated or extruded onto an outer wrap of a paper cup or container. The printing, spraying, laminating or extruding of the spacer elements can be done either off-line on existing equipment or can be done in-line on the cup-forming equipment. 
         [0012]    Once the spacer elements are applied to the exterior blank, the blank can then be wrapped around a cup. The spacer dots create an air space between the inner and outer blanks, thereby defining an insulating air space therebetween. The spacer elements can be made form acrylics or other plastics, hot melt, foamed starch or cellulose material, cork or other natural fibers and/or insulating materials. Virtually any material can be used to define the spacer elements that can be processed using conventional laminating, printing, spraying or extruding equipment, or that can be indexed (via label applicator or pick-and-place systems) onto the surface of the outer blank. 
         [0013]    The outer blank can be made of virgin or recycled paper, or virtually any grade of paper or paperboard to meet a specific end-use need. A specific grade of paper can be selected that would absorb the condensate that occurs from cold beverages, thereby creating an absorbable or sweat-resistant insulated cup. Clay-coated grades of paper can be utilized on the outer blank to enhance the printing and graphics of the insulated cup. Similarly, synthetic films and plastic sheet material may be utilized, if desired. The use of any naturally-occurring plastic film, fibrous raw material or naturally-occurring insulated material could also be used for the exterior of the insulated cup. 
         [0014]    Once the outer wrap is applied to the cup, an integral insulated cup has been created with an air pocket having been designed into the insulated cup due to the spacers. The number of spacer elements can vary from few to many, depending on the inherent stiffness of the inner and outer cup walls. The degree of insulation can be improved with thicker spacers vs. thinner spacers. 
         [0015]    The inner cup that is being used to produce the insulated container may use a variety of raw materials and thicknesses to achieve the cost and overall hand-holding characteristics desired for the insulated cup. 
         [0016]    These and other objects, features and advantages of the present invention become apparent to those of ordinary skill in the art from the description which follows, and may be realized by means of the instrumentalities and combinations particularly pointed out therein, as well as by those instrumentalities, combinations and improvements thereof which are not described expressly therein, but which would be obvious to those of ordinary and reasonable skill in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    A better understanding of the invention will be had upon reference to the following description in conjunction with the accompanying drawings in which like reference numerals represent like parts, and wherein: 
           [0018]      FIG. 1  is an exploded view of a beverage container according to a preferred embodiment of the present invention; 
           [0019]      FIG. 2  is a close-up partial section view of a lower portion of the container of  FIG. 1 , showing a cup bottom being captured by an inwardly-turned lip of an inner wall and showing an outer wall being in spaced relation to the inner wall; 
           [0020]      FIG. 3  is a close-up partial section view of an upper portion of the container of  FIG. 1 , showing an upper end of an outer wall being affixed to a generally-cylindrical portion of an inner wall and showing the outer wall being in spaced relation to the inner wall; and, 
           [0021]      FIG. 4  is a top plan view of a blank used to form an outer wall portion of the container shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    With reference to  FIG. 1 , a container  10  according to a preferred embodiment of the present invention includes an inner wall  20 , an outer wall  30  and a cup bottom  40 , each telescopingly fit one over the other so as to define an open-top, closed-bottom, double-wall cup configuration, as is known generally in the art. More particularly, the cup bottom  40  fits within the inner wall  20  and is positioned generally near a lower end thereof. The cup bottom  40  is defined by a circular top  41  and a downwardly-depending annular leg  42 . The lower end of the inner wall  20  includes an inwardly- and upwardly-turned annular lip  22  into which the annular leg  42  of the cup bottom  40  is captured and pinched so as to define a leak-proof closed lower end of the container  10 . The inner wall  20  is further provided with an outwardly-rolled bead  24  and a generally-cylindrical sidewall  25  extending between the rolled bead  24  and the annular lip  22 . 
         [0023]    Inner wall sidewall  25  more particularly includes a generally-cylindrical upper portion  25   a  positioned adjacent the rolled bead  24  and an inwardly-tapered frusto-conical main body portion  25   b  positioned adjacent the annular lip  22 . As can be seen from the figures, main body portion  25   b  preferably is more substantial than upper portion  25   a,  the purpose of which will be described in greater detail below. Upper portion  25   a  and main body portion  25   b  are connected to one another by a shoulder  26 , which serves as an inwardly-directed discontinuous radial transition from the upper portion  25   a  to the main body portion  25   b.  Inner wall  20  and cup bottom  40  each preferably are constructed from coated or uncoated paperboard and are manufactured to achieve the within-described configurations using ordinary manufacturing techniques. 
         [0024]    Outer wall  30  includes an inwardly-tapered frusto-conical sleeve portion  32  having an inwardly-tapered upper end  32   a  and an inwardly- and upwardly-rolled lower lip  32   b,  the purpose of which will be described in greater detail below. Outer wall  30  is sized to fit around inner wall  20 , which is telescopingly-received thereinto so as to define a double-wall container configuration. Outer wall  30  preferably is constructed from coated or uncoated paperboard and is manufactured to achieve the within-described configuration using ordinary manufacturing techniques. 
         [0025]    With reference now also to  FIGS. 2 and 3 , the manner in which inner wall  20 , outer wall  30  and cup bottom  40  are arranged so as to form an open-top, closed-bottom, generally leak-proof beverage container  10  is described. As mentioned above, cup bottom  40  is formed preferably from a flat, circular sheet of coated paperboard, which is folded downwardly along out periphery so as define circular top  41  and annular leg  42 . The cup bottom  40 , thus formed, is positioned towards the lower end of the inner wall  20 , which is formed by wrapping a flat sheet of coated paperboard around a mandrel (not shown) and sealing opposing ends (not shown) to one another, as is customary in cup-forming techniques. Lip  22  is folded inwardly and upwardly so as to capture and pinch cup bottom leg  42  therein. Lip  22  and leg  42  and then sealed to one another so as to define a generally leak-proof closed bottom of the container  10 . 
         [0026]    Outer wall  30  is thereafter wrapped around inner wall  20  using conventional cup-forming and wrapping techniques such that the inwardly-tapered upper end  32   a  of the outer wall  30  is positioned adjacent rolled bead  24  of the inner wall  20  and secured to the cylindrical portion  25   a  thereof, such as, for example, using coventional adhesive, heat or sonic sealing techniques. Rolled lower lip  32   b  of the outer wall  30  is allowed to rest against an outer surface of the inner wall  20 , near the lower end thereof, preferably adjacent the top  41  of the cup bottom  40 , which is positioned within the inner wall  20 . 
         [0027]    As can be seen clearly in  FIG. 3 , upper portion  25   a  of the inner wall  20  cooperates with shoulder  26  to ensure that an upper portion of the outer wall  30  is spaced outwardly from inner wall  20 , thereby defining an insulating air spaced therebetween. Similarly,  FIG. 2  shows clearly that rolled lower lip  32   b  ensures that a lower portion of the outer wall  30  is spaced outwardly from the inner wall, thereby defining a generally-constant thickness insulating air gap vertically from top-to-bottom of the container  10 . 
         [0028]    Referring now to  FIG. 4 , a blank used to form the outer wall  30  is shown onto which a plurality of spacer elements  38 , in the form of dots, have been printed or otherwise applied or deposited onto the surface of the blank. Although the spacer elements  38  may be arranged to form a matrix or other pattern, a random arrangement thereof may also be provided. In addition, although the spacer elements  38  are shown in the form of generally-circular dots, any shape thereof may be employed while staying within the spirit and scope of the present invention. Indeed, spacer elements may even take the form of stripes, ribs, ridges or other elongated configurations arranged either in parallel to one another or at angles relative to one another. 
         [0029]    Referring now back to  FIGS. 2 and 3 , it can be seen that spacer elements  38  extend from the outer wall  30  into the interior space defined by the inner wall  20  and the outer wall  30 , towards the inner wall  20 , but do not contact the inner wall  20  when the container  10  is in a relaxed (i.e., ungripped) state. The purpose of this is so that the interior space between the inner wall  20  and the outer wall  30  is substantially free from obstructions so as to maximize the movement of air therebetween, which is heated (or chilled) in response the beverage contained within the inner wall  20 . Allowing for the movement of such air eliminates localized pockets of hot (or cold) temperatures and facilitates an effective thermal equilibrium generally throughout the interior space between the inner wall  20  and the outer wall  30 . 
         [0030]    In use, a user grips the outside surface of the outer wall  30 . However, in ordinary use, the stiffness of the outer wall  30  is sufficient to prevent the outer wall  30  from contacting the inner wall  20  under the influence of the user&#39;s squeezing same. The spacer elements  38  are sized such that they do not come into contact with the inner wall  20  during normal use conditions. However, in the event the stiffness of the outer wall  30  is sufficiently low (or the user exerts a larger-than-normal squeezing force to the container) such that the outer wall  30  would come into contact with the inner wall  20  during normal use conditions, the spacer elements  38  would stop inward movement of the outer wall  30  relative to the inner wall  20  beyond a certain point so as to ensure that a minimum thickness to the air space defined therebetween is maintained. 
         [0031]    While the invention has been described and illustrated with reference to one or more preferred embodiments thereof, it is not the intention of the applicants that the invention be restricted to such detail. Rather, it is the intention of the applicants that the invention be defined by all equivalents, both suggested hereby and known to those of ordinary skill in the art, of the preferred embodiments falling within the scope hereof.