Patent Publication Number: US-2007102413-A1

Title: Heat preservation pad

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a heat preservation pad and particularly to a pad capable of keeping warm for a long period of time.  
      2. Description of the Prior Art  
      Nowadays many people love to keep pets. There are a wide variety of products on the market to cater the welfare of pets. To keep the pets warm in the cold weather is important. Hence many types of warming goods such as warming blankets and beds have been introduced to enable the pets without sleeping on a damp or cold floor and prevent the pets from inflicting ailments. Those goods are mostly heated electrically. Hence electric power has to be supplied constantly to generate heat energy and maintain a warm condition. If electric power supply is unstable or interrupted, or the unplugging of the power cord occurs due to messing around of the pets, warming keeping function of the warming blankets or beds become ineffective. Moreover, warming by supplying electric power constantly could result in the risk of overheating. This could produce a not comfortable condition to the pets.  
     SUMMARY OF THE INVENTION  
      In view of the problem occurred to the conventional heat preservation structure that cannot maintain a warm condition for a long period of time when the electric power is absent, the present invention aims to provide a heat preservation pad that can maintain a steady temperature for a long period of time to maintain a desired warm condition.  
      The invention mainly includes a base, a upper cap, an inner box and a heating assembly. The base and the upper cap are coupled together to form a housing compartment to hold the inner box. The inner box has a housing chamber to hold a wax as a heat transfer medium. The inner box has an opening sealed by a lid to form a closed condition and a bottom surface attached to the heating assembly to generate heat energy. The heating assembly has a thermostat which constantly detects the temperature of the inner box to turn on or off the supply of electric power. Through heat transfer of the inner box the heat preservation pad can maintain a warm condition. Therefore the temperature can be maintained as desired. Moreover, the heat preservation pad can be held in a pliable fabric pouch to enhance comfort and heat preservation. The wax has a low melting temperature and disperses heat slowly, thus can maintain a warm condition for a long period of time even if the electric power is cut off.  
      The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded view of the invention.  
       FIG. 2  is a sectional view of the invention in an assembled condition.  
       FIG. 3  is a schematic view of an embodiment of the invention.  
       FIG. 4  is a sectional view of an embodiment of the invention in an assembled condition. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIGS. 1 and 2 , the invention includes a base  11 , a upper cap  12 , an inner box  13  and a heating assembly  14 .  
      The base  11  is coupled with the upper cap  12  to form a chest  10  that has a housing compartment  111  to hold the inner box  13 . It also has a plurality of coupling posts  112  on the periphery and an anchor seat  113  on an outer side.  
      The upper cap  12  is coupled on a upper side of the base  11 , and has a heat receiving surface  123  on a upper side thereof and a housing trough  121  formed in the interior. It also has a plurality of struts  122  on the periphery corresponding to the coupling posts  112  of the base  11  so that they can be coupled together to form a housing space.  
      The inner box  13  is held in the housing space formed by the base  11  and the upper cap  12 , and has a housing chamber  131  to hold wax W. It has one or more trough  134  on the bottom and an opening  132  on one end, and apertures  133  on two sides to receive screws  136  to fasten to the base  11 . The opening  132  is sealed by a lid  135  to allow the housing chamber  131  to become a closed chamber.  
      The heating assembly  14  is located on the bottom side of the inner box  13  and has electric heating coils  141  located thereon, and is coupled with a socket  142 . The socket  142  is held in the anchor seat  113  of the base  11 . The heating assembly  14  further has a thermostat  143  to control the heating temperature.  
      By means of the aforesaid structure, a heat preservation pad  1  is formed. The socket  142  can be coupled with a plug to receive electric power. After energized by the electric power, the heating assembly  14  generates heat energy to melt the wax W contained in the housing chamber  131  to become liquid. The heat can be transferred evenly to the entire heat receiving surface  123  to achieve a steady heating effect. The thermostat  143  can automatically cut off electric power to prevent overloading and overheating of the heat preservation pad  1 . After being heated to a set temperature, the power supply can be unplugged from the heat preservation pad  1  so that the pad can be used for holding the pets. As the wax W has a low melting temperature and disperses heat slowly, it will release heat energy and condense slowly. Hence the heat preservation pad  1  can maintain a warm condition for a long period of time (about eight hours).  
      In addition, the heat preservation pad  1  can also be held in a pouch  2  (as shown in  FIGS. 3 and 4 ). The pouch  2  is made from a pliable fabric and can aid heat preservation. It has an opening  21  on one end to facilitate loading and unloading of the heat preservation pad  1 . Thus pets can seat and lie comfortably on the pad in a warm condition.