Abstract:
Cold therapy is an established practice used in the medical profession to treat certain limb injuries, such as sprained or strained arm or leg muscles or injuries to joints. Generally, these types of injuries should be chilled to slow blood flow, which reduces swelling, pain, and further damage. Cold therapy is also an established practice used to treat migraine and other types of headaches. A typical course of cold therapy treatment is to apply ice for a specified period to the injured region of a limb, the neck, face, or head. Alternatively, a pack or bag containing a chemical agent that reacts (endothermically) to produce cold may be applied to the injured region, the neck, face, or head.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Cold therapy is an established practice used in the medical profession to treat certain limb injuries, such as sprained or strained arm or leg muscles or injuries to joints. Generally, these types of injuries should be chilled to slow blood flow, which reduces swelling, pain, and further damage. Cold therapy is also an established practice used to treat migraine and other types of headaches. A typical course of cold therapy treatment is to apply ice for a specified period to the injured region of a limb, the neck, face, or head. Alternatively, a pack or bag containing a chemical agent that reacts (endothermically) to produce cold may be applied to the injured region, the neck, face, or head. 
         [0002]    A number of devices that use endothermic reactions for cooling body parts are known. For example, U.S. Pat. No. 4,986,076 to Kirk et al. and U.S. Pat. No. 2,898,744 to Robbins both disclose a flexible, plastic cooling bag sealed along its edges. The cooling bag is separated by a frangible barrier into two portions: a freezing chemical mixture (salt) portion and a liquid (water) portion. A cooling reaction is activated by squeezing or applying pressure to the bag, which ruptures the frangible barrier and thus allows the salt and liquid portions to mix. The resulting chemical mixture causes an endothermic reaction, which produces a cooling effect. The cooled bag is applied to a body part. 
         [0003]    A concern with such endothermic cold packs is that the solution that is formed ends up at the bottom (i.e., the lowest point) of the enclosure. The localization of the solution within the enclosure results in temperature differences within the cold pack. The temperature differences that are generated within the cold pack cause the cold pack to cool various sections of an area at differing rates. 
         [0004]    Accordingly, there is a need for a cold pack that uniformly cools an area of the body. The cold pack should also be readily portable and adaptable for various needs of users. 
       SUMMARY OF THE INVENTION 
       [0005]    The present inventors undertook intensive research and development efforts concerning improving instant cold therapy. The present invention is directed in part to a cold pack including an enclosure, a solute within the enclosure, a liquid within the enclosure, and a membrane segregating the liquid from the solute. Further, rupturing the membrane mixes the liquid with the solute to produce an endothermic solution within the enclosure. In addition, the enclosure includes a first compartment, a second compartment, and a connection between the first compartment and the second compartment. The connection is adapted to pass the endothermic solution between the first and the second compartment. 
         [0006]    Another aspect of the present invention is directed to a cold pack including an enclosure, a solute within the enclosure, a liquid within the enclosure, and a membrane segregating the liquid from the solute. Further, rupturing the membrane mixes the liquid with the solute to produce an endothermic solution within the enclosure. In addition, the enclosure includes a first compartment, a second compartment, and a connection between the first compartment and the second compartment. The connection is adapted to pass the endothermic solution between the first and the second compartment. Further, a force other than gravity is needed for the endothermic solution to pass through the connection between the first compartment and the second compartment. Additionally, the cold pack includes a mechanism for temporarily blocking the connection between the first compartment and the second compartment to prevent the endothermic solution from passing between the first compartment and the second compartment. 
         [0007]    A third aspect of the present invention is directed to a cold pack including an enclosure, a solute within the enclosure, a liquid within the enclosure, and a membrane segregating the liquid from the solute. The liquid may be water. The solute may be ammonium nitrate, and the membrane may be polyethylene. Further, rupturing the membrane mixes the liquid with the solute to produce an endothermic solution within the enclosure. In addition, the enclosure includes a first compartment, a second compartment, and a connection between the first compartment and the second compartment. The connection is adapted to pass the endothermic solution between the first and the second compartment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The present invention will be more fully understood, and further features will become apparent, when reference is made to the following detailed description and the accompanying drawings. The drawings are merely representative and are not intended to limit the scope of the claims. Like parts depicted in the drawings are referred to by the same reference numerals. 
           [0009]      FIG. 1  illustrates a schematic section view of a cold pack. 
           [0010]      FIG. 2  illustrates a schematic section view of the cold pack shown in  FIG. 1  with a membrane ruptured within the cold pack to produce an endothermic solution within the cold pack. 
           [0011]      FIG. 3  illustrates a schematic section view of another cold pack. 
           [0012]      FIG. 4  illustrates a schematic section view of the cold pack shown in  FIG. 3  with a membrane ruptured within the cold pack to produce an endothermic solution within the cold pack. 
           [0013]      FIG. 5A  illustrates a plan view of yet another cold pack with multiple compartments. 
           [0014]      FIG. 5B  illustrates a plan view of the cold pack shown in  FIG. 5A  in a first orientation with a membrane ruptured within the cold pack to produce an endothermic solution where the endothermic solution is distributed in one compartment within the cold pack. 
           [0015]      FIG. 5C  illustrates a plan view of the cold pack shown in  FIG. 5B  in a second orientation with a membrane ruptured within the cold pack to produce an endothermic solution. 
           [0016]      FIG. 5D  illustrates a plan view of the cold pack shown in  FIG. 5A  in a first orientation with a membrane ruptured within the cold pack to produce an endothermic solution where the endothermic solution is distributed in more than one compartment within the cold pack. 
           [0017]      FIGS. 6A-6D  illustrate several different cold packs with enclosures having compartments and connections between the compartments. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    In the following detailed description, reference is made to the accompanying drawings which show specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other embodiments may be utilized and structural changes made, such that the following detailed description is not to be taken in a limiting sense. 
         [0019]      FIGS. 1 and 2  illustrate a cold pack  10 . The cold pack  10  includes an enclosure  11  with a solute  12  and a liquid  14  sealed inside the enclosure  11 . The solute  12  and the liquid  14  are segregated within the enclosure  11  by a membrane  16  (see  FIG. 1 ). Rupturing the membrane  16 , for example by applying pressure to the enclosure  11 , mixes the liquid  14  (e.g., water) with the solute  12  to produce an endothermic solution  18  within the enclosure  11  (see  FIG. 2 ). Substantially all of the solute  12  rapidly dissolves within the liquid  14  such that the cold pack  10  quickly reaches its cooling temperature. 
         [0020]    Cold pack  10  may also include an insulation layer  19  that insulates a portion of the enclosure  11  from the surrounding environment. It should be noted that insulation layer  19  may have any size or shape and may be in or on the enclosure  11 . Insulation layer  19  should be positioned on a side of enclosure  11  that is opposite to the side of enclosure  11  which is to be located on, or near, the body. The insulation layer  19  then serves to reduce warming of the cold pack  10  by the ambient environment without inhibiting heat transfer from the body to the cold pack  10 . 
         [0021]    Membrane  16  may be polyethylene (among other materials). In addition, any conventional solutes may be used to induce an endothermic reaction within cold pack  10 . One example solute includes ammonium nitrate. The rate at which the solute dissolves into the liquid, and thus the rate of cooling, may be affected by the particle size of the solute. For example, if a rapid dissolution is desired, the pieces that form the solute  12  may be between about 0.001 and 0.025 inches, although it should be noted that smaller pieces may be used and some small minority of pieces may be larger than 0.025 inches. 
         [0022]      FIGS. 3 and 4  illustrate a cold pack  10 . The cold pack  10  includes an enclosure  11  and a liquid  14  and a solute  12  sealed inside the enclosure  11 . The solute  12  and the liquid  14  (e.g., water) are segregated within the enclosure  11  by a membrane  16 . 
         [0023]    The cold pack  10  further includes an absorbent core, such as absorbent layer  27 , within the enclosure  11  (see  FIG. 3 ). The absorbent layer  17  retains an endothermic solution  18  that is formed within the enclosure  11  by rupturing the membrane  16  (see  FIG. 4 ). Once the solute  12  and the liquid  14  are mixed to form the endothermic solution  18 , the absorbent layer  17  spreads the endothermic solution  18  throughout the enclosure  11  such that the cold pack  10  uniformly cools an injured portion of a body when the cold pack  10  is positioned on, or near, the body. 
         [0024]    The membrane  16  may also isolate the absorbent layer  17  from the solute  12  and/or the liquid  14  until the membrane  16  is ruptured to mix the solute  12  and the liquid  14 . In some sample forms, the solute  12  may be interspersed with the absorbent layer  17  before membrane  16  is ruptured. The absorbent core may take forms other than absorbent layer  17  and may be pulp fiber (among other materials). 
         [0025]    It should be noted that in the example cold pack  10  illustrated in  FIGS. 3 and 4 , solute  12  may be in pellet or powder form. In addition, cold pack  10  may include an insulation layer  19  which is similar to insulation layer  19  described above with regard to  FIGS. 1 and 2 . 
         [0026]    In some example embodiments, the solute  12  may be integral with the absorbent layer  17  as opposed to being initially isolated from the absorbent layer  17 . Although not specifically illustrated, these types of example embodiments may include an enclosure  11  and a membrane  16  that initially segregates a liquid  14  from a solute-filled absorbent layer  17  within the enclosure  11 . Combining the solute  12  with the absorbent layer may simplify fabrication of such cold packs. 
         [0027]      FIGS. 5A-5D  illustrate a plan view of yet another cold pack  10  with multiple compartments  21 ′,  21 ″,  21 ′″ within the enclosure  11 . The enclosure  11  also includes connections  23 ′,  23 ″ that are adapted to pass material between the compartments such as liquid  14 , solute  12 , or endothermic solution  18 . The cold pack  10  illustrated in  FIGS. 5A-5D  includes a first compartment  21 ′, a second compartment  21 ″, and a third compartment  21 ′″. This cold pack  10  may be suitable for treating the forehead and temples. The first compartment  21 ′ may generally correspond with the area of the cold pack  10  that contacts the forehead. The second compartment  21 ″ and the third compartment  21 ′″ may generally correspond with areas of the cold pack  10  that contact the temples. 
         [0028]    Sufferers of headaches, and in particular migraine headaches, may find it comforting to lie down, or be in a reclined position while applying cooling to their heads. Further, sufferers of headaches may also desire a uniform distribution across the temple and forehead area. The compartments  21 ′,  21 ″,  21 ′″, and connections  23 ′,  23 ″ allow for the endothermic solution  18  to move around the enclosure  11  under certain situations, and prevent movement of the endothermic solution  18  around the enclosure  11  under other situations. Specifically, with the cold pack  10  in a first orientation in relation to gravity as shown in  FIGS. 5A ,  5 B, and  5 D with indicator arrow  25  pointed in the upward direction, the connections  23 ′,  23 ″ are positioned near top of the enclosure  11 , such that the endothermic solution  18  does not pass through the connections  23 ′,  23 ″. However, with the cold pack  10  in a second orientation in relation to gravity as show in  FIG. 5C  with indicator arrow  25  pointed downward, the connection  23 ′,  23 ″ are positioned near the bottom of the enclosure  11 , such that the endothermic solution  18  does pass between the compartments  21 ′,  21 ″, and  21 ′″. A user may distribute the endothermic solution  18  between the first, second, and third compartments  21 ′,  21 ″,  21 ′″ in a manner that best suits their needs. For example, one sufferer may chose to have equal amounts of endothermic solution  18  in each of the compartments  21 ′,  21 ″,  21 ′″, while another sufferer may choose to have a disproportionate amount of endothermic solution in the first (center) compartment  21 ′. Regardless, the compartments  21 ′,  21 ″,  21 ′″ and connections  23 ′,  23 ″ allow the sufferer the ability to counteract the natural distribution of liquid that gravity would affect on an open enclosure. 
         [0029]    The cold pack  10  is illustrated in  FIGS. 5A-5D  in four distinct configurations. In the first configuration, illustrated in  FIG. 5A , the membrane  16  is intact, and the liquid  14  and the solute  12  are separate. In the second configuration, illustrated in  FIG. 5b , the membrane  16  has been ruptured and the solute  12  and the liquid  14  have formed an endothermic solution  18 . Further in this second configuration, the endothermic solution  18  is contained exclusively within the first compartment  21 ′, and endothermic solution does not pass through the connection  23 ′,  23 ″. In the third configuration, illustrated in  FIG. 5C , the cold pack has been oriented such that the endothermic solution  18  has passed through the connection  23 ′,  23 ″ into the second compartment  21 ″, and the third compartment  21 ′″. As illustrated in  FIG. 5C , the endothermic solution  18  may be distributed proportionately in each compartment  21 ′,  21 ″,  21 ′″. In the fourth configuration, illustrated in  FIG. 5D , the endothermic solution is distributed disproportionately in the compartment  21 ′,  21 ″,  21 ′″, specifically a proportionally larger amount of endothermic solution  18  is located in the second compartment  21 ″, and the third compartment  21 ′″ than is located in the first compartment  21 ′. Depending on the specific design and use of the cold pack  10 , a user may choose to locate various amounts of endothermic solution  18  in the compartments  21 ′,  21 ″,  21 ′″. 
         [0030]    Endothermic solution may pass between the compartments  21 ′,  21 ″,  21 ′″ under the force of gravity. Alternatively, the connection  23 ′,  23 ″ may be designed such that a force other than gravity is needed for the endothermic solution  18  to pass through the connection between the compartments  21 ′,  21 ″,  21 ′″. This force may be pressure applied to the exterior of the enclosure  11  increasing the pressure of the endothermic solution  18  in one of the compartments  21 ′,  21 ″,  21 ′″ in relation to another compartment  21 ′,  21 ″,  21 ′″. 
         [0031]    The compartments  21 ′,  21 ″,  21 ′″ may be formed in any suitable manner. For example, the enclosure  11  may be formed from two planar sheets of material joined together along the periphery of the two sheets. The compartments  21 ′,  21 ″,  21 ′″ may be formed by joining portions of the two sheets forming the compartments  21 ′,  21 ″,  21 ′″. The sheets may be joined using thermal, ultrasonic, or adhesive bonding. Alternatively, two or three compartments  21 ′,  21 ″,  21  ′″ may be formed separately, and then joined with connections. For example, the connections may be straws or tubes which connect the compartments  21 ′,  21 ″,  21 ′″. 
         [0032]    The connections  23 ′,  23 ″ may be adapted to remain open at all times. Alternatively, the connections  23 ′,  23 ″ may be adapted to be blocked either temporarily or permanently. For example, the material which surrounds the connection  23 ′,  23 ″ may be elastic such that by applying tension the connection  23 ′,  23 ″ opens and allows endothermic solution  18  to pass between the compartments  21 ′,  21 ″,  21 ′″. Further, upon release of the tension, the connections  23 ′,  23 ″ may become blocked, preventing the endothermic solution  18  from passing between the compartments  21 ′,  21 ″,  21 ′″. Many suitable devices may be used to temporarily block the connection  23 ′,  23 ″, for example, a valve, a clip, a tie, a plug, or a zipper seam may be used. As used herein, the term “zipper seam” refers to self-mating rib and flange seams such as are commonly used with sandwich bags. A suitable zipper seam is described in U.S. Pat. No. 6,544,604 issued Apr. 15, 2003 to Galkiewicz et al. Many suitable devices may be used to permanently block the connection  23 ′,  23 ′″; for example, an adhesive, a thermal seal, or a solvent weld. 
         [0033]    Depending on the specific design and desired final use of the cold pack  10 , the solute  12  and the liquid  14  may be located anywhere within the enclosure  11 . For example the solute  12  may be located in the first compartment  21 ′ and the liquid  14  may be located in the second compartment  21 ″. Alternatively the solute  12  may be located in the first compartment  21 ′ and the liquid  14  may also be located in the first compartment  21 ′. 
         [0034]    The first compartment  21 ′ and the second compartment  21 ″ may include absorbent core  17  adapted to retain the endothermic solution  18 . For example the first compartment  21 ′ may include an absorbent core  17  while the second compartment  21 ″ may not include an absorbent core  17 . This may be advantageous where the first compartment  21 ′ is adapted to be used such that it is elevated relative to the second compartment  21 ″ during use, for example where the first compartment  21 ′ is adapted to be used on the forehead and the second compartment  21 ″ is adapted to be used on a temple when the user is in a reclined position. In this configuration, the second compartment  21 ″ may or may not include a second absorbent core. 
         [0035]      FIGS. 6A-6D  illustrate several different cold packs with enclosures having compartments and connections between the compartments.  FIG. 6A  illustrates a cold pack  10  having five compartments  21 , and four connections  23  between the compartments  21 . As illustrated in  FIG. 6A , the connections  23  are located at the top and bottom of the enclosure  11 , alternating top to bottom from left to right. This cold pack  10  may be suitable for use in cooling an ankle or a neck. 
         [0036]      FIG. 6B  illustrates a cold pack  10  having two compartments  21  and one connection  23  between the compartments  21 . As illustrated in  FIG. 6B , the compartments  21  are located at opposite ends of a relatively long connection  23 . This cold pack  10  may be suitable for use in cooling the left and right temple, or the left and right side of a knee, ankle, elbow, or shoulder. 
         [0037]      FIG. 6C  illustrates a cold pack  10  having seven compartments  21  and six connections  23  between the compartments  21 . As illustrated in  FIG. 6C , the cold pack  10  is designed and shaped to cover the eyes of a user, with a notch for the nose. The compartments  21  and connections  23  are designed such that a user may distribute endothermic solution such that a uniform cooling may occur around the eyes. 
         [0038]      FIG. 6D  illustrates a cold pack  10  having six compartments  21  and six connections  23  between the compartments  21 . As illustrated in  FIG. 6C , cold pack  10  is generally circular in shape and the compartments  21  have the shape of a sector of a circle of approximately 60 degrees. The connection  23  is located at the center of the circle. This cold pack  10  may be suitable for use in cooling the knee, elbow, shoulder, or ankle. 
         [0039]    In alternative forms, the cold pack  10  may include numerous additional features. For example the cold pack  10  may include outer covers made from a wide variety of materials, including, for example, woven fabrics and nonwoven fabrics or webs. Nonwoven materials suitable for use with the present invention include, for example, a multilayer laminate such as a spunbond/meltblown/spunbond (“SMS”) material. An example of such a fabric is disclosed in U.S. Pat. No. 4,041,203 and is hereby incorporated by reference. Additional features may include material adapted to extending the cooling duration of the cold pack  10 , for example as disclosed in U.S. Pat. No. 6,881,219 and hereby incorporated by reference. 
         [0040]    In alternative forms, a release layer (not shown) may be detachably mounted to the cold pack using an adhesive. The release layer may be removed from the cold pack leaving only the adhesive on the cold pack. The remaining adhesive provides a means for directly or indirectly securing the cold pack to a body, flexible wrap, and/or other device. 
         [0041]    A method of cooling a portion of a body is described herein with reference to  FIGS. 5A-5D  and  FIGS. 6A-6D . In one form, the method includes segregating a solute  12  from a liquid  14  where the solute  12  and the liquid  14  are inside of a cold pack  10  ( FIGS. 5A ,  6 A- 6 D). The method further includes mixing the solute  12  with the liquid  14  to form an endothermic solution  18  within the cold pack  10 , distributing the endothermic solution  18  though connections  23  within the cold pack  10 , and applying the cold pack  10  to the portion of the body. In some sample forms of the method, mixing the solute  12  and the liquid  14  to form an endothermic solution  18  includes rupturing a membrane  16  that segregates the solute  12  from the liquid  14  within the cold pack  10 . 
         [0042]    In some sample forms of the method, distributing the endothermic solution  18  throughout the cold pack  10  includes retaining the endothermic solution  18  within an absorbent core, such as absorbent layer  27 . In some alternative forms, the method includes mixing the solute  12  and the liquid  14  within the absorbent layer  17 . It should also be noted that the solute  12  may be in pellet form or powder form. 
         [0043]    The size and shapes of the cold packs described herein will depend on the applications where the cold packs will be used (among other factors). In addition, the membranes within the enclosures may have any size, number, arrangement, and configuration as long as the membrane (i) segregates the solute from the liquid; and (ii) is capable of being ruptured so that the solute can be mixed with the liquid to form an endothermic solution. 
         [0044]    The operations discussed above with respect to the described methods may be performed in a different order from those described herein. It should be noted that attaching a cold pack to a body includes attaching the cold pack directly or indirectly to the body. In addition,  FIGS. 1-6D  are representational and are not necessarily drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. 
         [0045]    While the invention has been described in detail with respect to the specific aspects thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of, and equivalents to these aspects which fall within the spirit and scope of the present invention, which should be assessed accordingly to those of the appended claims.