Abstract:
An insole has an upperside and an underside narrower than the upperside, so as to give an added support, wearing stability, and comfort to the foot.

Description:
[0001]    This is a continuation-in-part of copending parent application Ser. No. 09/702,661, filed Nov. 1, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to a shoe, and more particularly to an improved flat insole of the shoe.  
         BACKGROUND OF THE INVENTION  
         [0003]    Conventional shoe insoles normally comprise either flat insoles or flat insoles which are formed to a shape by heating under pressure in a mold. The molded insole affords stability and support to the foot sole in contact with it. However, the molded insole is made at an extra cost and because it is made under pressure, it has a greater rigidity. The rigid molded insole has a lower soothing effect. The process of making the molded insole is costly in view of the fact that the process consumes energy, and that the material cost increases. For example, a flat insole having a thickness of 6 mm is needed to make a modeled insole having a thickness of 4 mm. The flat insole is relatively cost-effective and is made of a foam material which is relatively soft. However, the flat insole is less desirable than the molded insole in terms of stability and support.  
           [0004]    As shown in FIG. 1, the inner wall  71  of a shoe  70  is arcuate. A conventional flat insole  30  is corresponding in size to the shoe sole  71  and is insufficient to cover the foot  100 . In addition, the central portion of this insole  30  is prone to cave in from body weight of a person wearing the shoe  70 . As a result, the upperside edge  301  of the insole  30  is apt to warp to press against the foot sole.  
           [0005]    As shown in FIGS. 2 and 3, the conventional flat insole  30 ′ is greater in size than the shoe sole  71  to cover sufficiently the foot  100 . However, the upperside edge  301 ′ tends to press against the foot sole. In addition, the juncture between the flat insole  30 ′ and the inner wall  72  of the shoe sole  71  tends to have a void, which permits the flat insole  30 ′ to wrinkle and displace easily. In addition, the insole  30 ′ can not be securely kept in place in the shoe sole  71 .  
           [0006]    Conventional flat insoles are generally devoid an arch to prevent the formation of a void and the pressing of the upperside edge against the foot sole. In light of the formation of a void under the arch, the arch is somewhat suspended, thereby resulting in a great deal of discomfort.  
         SUMMARY OF THE INVENTION  
         [0007]    The primary objective of the present invention is to provide a flat insole made of foam material and not molded under heat and pressure which is free of the shortcomings of the conventional insoles described above.  
           [0008]    The flat insole of the present invention has an upperside and an underside which is smaller in width than the upperside. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 shows a schematic view of a prior art flat insole in use.  
         [0010]    [0010]FIG. 2 shows a schematic view of the prior art flat insole at work.  
         [0011]    [0011]FIG. 3 shows a schematic view of another prior art flat insole at work.  
         [0012]    [0012]FIG. 4 shows a front view of the present invention.  
         [0013]    [0013]FIG. 5 shows a side view of the present invention.  
         [0014]    [0014]FIG. 6 shows a schematic view of the present invention at work.  
         [0015]    [0015]FIG. 7 shows another schematic view of the present invention at work. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    As shown in FIGS. 4 and 5, a flat insole  10  of the present invention is made of a foam material not molded under heat and pressure and is composed of a toe portion  11 , a sole portion  12 , a heel portion  13 , and an arch  121  extending from the sole portion  12 . The flat insole  10  has two longitudinal side walls which slant from two upperside edges  101  such that the two longitudinal side walls form respectively angles α and β with an underside of the insole  10 . The α angle and the β angle are greater than 90 degrees. As a result, the flat insole  10  has an upperside and an underside which is smaller in width than the upperside. The toe portion has the smallest machining angle. The heel portion  13  has the intermediate machining angle. The arch  121  of the sole portion  12  has the greatest machining angle. The slanted longitudinal side walls of the flat insole  10  have arcuate edges.  
         [0017]    As shown in FIG. 6, the flat insole  10  is kept in place in a shoe  70  such that no void is formed between the heel portion  13  and the inner wall  72  of the shoe  70 , and that the upperside edges  101  of the flat insole  10  are in an intimate contact with the inner wall of the shoe  70 , thereby preventing the upperside edges  101  from warping to press against the sole of a foot wearing the shoe  70 .  
         [0018]    In light of the flat insole  10  of the present invention being provided with the arch  121 , the flat insole  10  is capable of covering the foot sole  100 . As shown in FIG. 7, the arch  121  is in contact with the inner wall  72  of the shoe to prevent the formation of a large void.  
         [0019]    The flat insole  10  of the present invention is securely kept in place in the shoe such that the flat insole  10  is in an intimate contact with the inner wall  72  of the shoe, so as to prevent the flat insole  10  from displacing or twisting.  
         [0020]    The flat insole of the present invention affords a good support to the foot wearing the shoe, thanks to the arch  121  of the flat insole  10 . The arch  121  is in contact with the inner wall  72  of the shoe such that only small void  8  is formed.  
         [0021]    The flat insole  10  makes an intimate contact with the inner wall  72  and has a wider upperside to cover the foot sole  100  without pressing against the foot sole.  
         [0022]    The flat insole  10  of the present invention is free of the drawbacks of the conventional flat insole which is prone to warp to press against the foot sole. The present invention affords its wearer comfort.  
         [0023]    Unlike the conventional flat insole and the conventional molded insole, the flat insole  10  of the present invention has a greater allowance for error. As a result, the flat insole  10  of the present invention fits better into the shoe sole  71 .  
         [0024]    The flat insole  10  of the present invention is cost-effective in all respects.