Abstract:
Support is provided to the foot of a shoe wearer by an air cushion that includes a support chamber surrounding a collapsible pump operable by the foot of the wearer for directing compressed air into the support chamber and varying the firmness of the chamber. The support chamber is of a preformed three-dimensional configuration of sufficient rigidity to provide stable support to the foot prior to receiving compressed air from the pump.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application is a continuation-in-part of application Ser. No. 09/388,540, filed on Sep. 2, 1999. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to a self-inflatable air cushion for use in shoes, and more particularly to such an air cushion which includes a pump in the form of a collapsible plenum chamber, a support chamber surrounding the pump, and a valve connected between the pump and the support chamber for permitting air to be driven from the pump into the support chamber by compressing the pump with the foot of the user.  
           [0003]    A conventional air cushion of this type is generally comprised of a collapsible three-dimensional body defining a plurality of air cells and a plurality of passages connecting the air cells. An air valve is also connected to the passages and disposed outside the sole of the shoe. When the air cushion is to be inflated, an air pump is attached to the air valve and operated to pump air into the air cells. If the inside pressure of the air cushion is excessively high, it cannot be regulated. Moreover, known cushions of this type may also include a pump which is surrounded by a support chamber that is also inflated by the pump. However, this known construction has a distinct disadvantage in that the chamber surrounding the pump is a of a two-dimensional configuration until it has been inflated by the pump. Accordingly, the chamber is always softer than the pump until inflation has been realized. Conventional cushions of this type are incapable of providing stable support for the foot of the user until the cushion has been sufficiently inflated with air.  
         SUMMARY OF THE INVENTION  
         [0004]    It is an object of the present invention to provide a self-inflatable air cushion which comprises a pump in the form of a collapsible plenum chamber having an air hole, a support chamber surrounding the pump, an air passage providing communication between the support chamber and the pump, and an one-way valve disposed in the air passage for permitting air to pass from the pump to the support chamber. When the pump is compressed by the foot of the user, air is forced out of the pump through the one-way valve and into the support chamber. When the foot is released, outside air is drawn into the pump through the air hole. In this way, the firmness of the support chamber may be adjusted. The support chamber is formed from an appropriate material, such as a polymer plastic, which permits it to maintain a preformed three-dimensional structure having sufficient rigidity to provide support for the foot of the user before it has received compressed air from the pump.  
           [0005]    According to another object of the invention, a relief valve or pressure regulating chamber is provided to regulate the inside pressure of the support chamber to a desired level.  
           [0006]    A still further object of the present invention includes providing a pressure accumulation chamber which has one end connected to the pump through an one-way valve for permitting air to flow from the pump to the pressure accumulation chamber, and an opposite end connected to the support chamber through an one-way valve for permitting air to flow from the pressure accumulation chamber to the support chamber. When the pump is compressed, compressed air is driven from the pump chamber into the pressure accumulation chamber. Since the support chamber is simultaneously subjected to an external pressure, the compressed air pressure of the pressure accumulation chamber is prevented from passing to the support chamber. When the external pressure is released from the support chamber, the compressed air of the pressure accumulation chamber is permitted to pass to the interior of the support chamber. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a perspective view of a self-inflatable air cushion according to a first embodiment of the present invention  
         [0008]    [0008]FIG. 2 is a perspective view of a self-inflatable air cushion according to a second embodiment of the present invention;  
         [0009]    [0009]FIG. 3 is a perspective view of the first embodiment, showing the self-inflatable air cushion mounted in an insole of a shoe and operated by the foot of a user;  
         [0010]    [0010]FIG. 4 is a top plain view showing a third embodiment of the present invention:  
         [0011]    [0011]FIG. 4A is a sectional view taken along the line  4 A- 4 A of FIG. 4;  
         [0012]    [0012]FIG. 4B is a sectional view taken along the line  4 B- 4 B of FIG. 4;  
         [0013]    [0013]FIG. 4C is a sectional view showing the turning direction of the plenum chamber or pump of the third embodiment shown in FIG. 4;  
         [0014]    [0014]FIG. 4D is a sectional view showing the pump of the third embodiment disposed in the top recess of a corresponding support chamber;  
         [0015]    [0015]FIG. 5 is a sectional view of a fourth embodiment of the present invention, showing the installation of the pressure regulating rod in the pressure regulating chamber: and  
         [0016]    [0016]FIG. 5A is a sectional view taken along the line  5 A- 5 A of FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    Referring to FIG. 1, a self-inflatable air cushion  1 A is shown comprising a support chamber  1 , an open space  21  surrounded by support chamber  1 , a plenum chamber in the form of a pump  10  disposed in open space  21  and provided with an air hole  31  at a top side thereof, an air cylinder  22  having a rear end disposed in communication with the support chamber  1 , a tube  33  forming a passage connecting the pump  10  and air cylinder  22 , an one-way valve  101  mounted in the air cylinder  22  for permitting air to pass from the pump  10  through the air cylinder  22  to the interior of the support chamber  1 , and a relief valve  103  mounted in a front end of air cylinder  22  for releasing compressed air to the atmosphere.  
         [0018]    Support chamber  1  and pump  10  collectively form a cushion system having a central portion defined by pump  10  and an outside portion defined by support chamber  1 . Pump  10  functions as an air pump which is actuated by the foot of the user and receives airthrough air hole  31 , the air being compressed by the foot of the user and is directed through tube  33 , air cylinder  22  and into support chamber  1 .  
         [0019]    Pump  10  is formed from a material, such as a plastic polymer, which is relatively soft and has a flexible quality to permit it to resume its original shape when pressure from the foot of the user is released therefrom. By contrast, support chamber  1  is formed from a more rigid material, preferably selected from a plastic polymer, which permits surround chamber to maintain a preformed three-dimensional structure before compressed air is pumped into the interior thereof. The amount of compressed air pumped into support chamber  1  by the user determines the degree of firmness desired. Since support chamber  1  is formed of a more rigid material, it maintains itself as a constant three-dimensional structure and, in this manner, always provides stable support for the foot of the user prior to the introduction of compressed air therein. Thus, the cushion system includes a center portion defined by pump  10  that is always softer than a rigid outside portion defined by support chamber  1 , whether or not compressed air is introduced into support chamber  1  by pump  10 .  
         [0020]    [0020]FIG. 2 shows an alternate form of the present invention. According to this form, the air cushion comprises a support chamber  1 , an air cylinder  22  connected to support chamber  1  at one side thereof, a plenum chamber in the form of a pump  10  spaced from the air cylinder  22  at a side opposite to support chamber  1 , and a tube  34  forming an air passage connecting air cylinder  22  and pump  10 . An one-way valve  101  is mounted in air cylinder  22  for permitting air to be delivered from the pump  10  to support chamber  1 , and a relief valve  103  is mounted at a front end of air cylinder  22  for releasing compressed air to the atmosphere.  
         [0021]    Referring to FIG. 3, air cushion  1 A is shown mounted inside a shoe with pump  10  projecting out of a top hole  61  of an insole  6  at the heel area of the shoe. When the foot of the user compresses pump  10 , air inside pump  10  is pressurized and forced through tube  33 , air cylinder  22  and into support chamber  1 . When the foot of the user is lifted away from pump  10 , external air is immediately drawn into pump  10  through air hole  31  due to an air pressure difference between the pressure with pump  10  and the exterior atmospheric pressure. If the user continuously compresses pump  10 , support chamber  1  will eventually be filled with compressed air to a saturated status. When support chamber  1  is fully filled with compressed air, support chamber  1  functions as a surrounding support structure around pump  10  against outside pressure. The user may adjust the pressure of compressed air within support chamber  1  to a desired level by operating relief valve  103 .  
         [0022]    Referring to FIGS. 4, 4A and  4 B, outside air passes from the air hole  31  into the pump  10 . When the foot of the user applies compressive pressure to pump  10 , air hole  31  is closed by the foot of the user and air within the interior of pump  10  is compressed by the foot of the user and pressurized to flow through an air passage  3   b  to a pressure regulating chamber  304  and then through a first one-way valve  101  to a pressure accumulation chamber  6 . The pressure accumulation chamber  6  is disposed in a position in which it bears no pressure when support chamber  1  or pump  10  receives compressive pressure from the foot of the user. Therefore, compressed air is allowed to be forced out of pump  10  into the pressure accumulation chamber  6  and thereafter through a second one-way valve  102  into support chamber  1  through an air passage  3   a.    
         [0023]    Referring to FIGS. 4C and 4D, pump  10  may be turned backwards through about 180° and positioned within a top recess  10   a  of support chamber  1  with its air hole  31  facing upwardly.  
         [0024]    Referring to FIGS. 5 and 5A, a pressure regulating rod  301  is mounted in pressure regulating chamber  304 . Pressure regulating rod  301  is a hollow rod having a longitudinal center passageway  53 , a plurality of recessed holes  54 , and a plurality of radial through holes  52  in communication with center passageway  53 . Recessed holes  54  and through holes  52  are arranged in correspondence with a plurality of distribution channels  51 , a first one-way valve  101 , a second one-way relief valve  102  and air passage  3   a.  The pressure in pressure accumulation chamber  6  and support chamber  1  may be regulated by rotating pressure regulating rod  301 . When through holes  52  are moved away from communication with air passage  3   a,  compressed air is prohibited from passing from pump  10  to the support chamber  1  through air passage  3   a.  When air passage  3   a,  through holes  52  and distribution chambers  51  are disposed in communication with one another through longitudinal center passageway  53 , pressurized air is permitted to pass into pressure accumulation chamber  6  subject to the volume of distribution chambers  51 .  
         [0025]    As an example, assume the inside volume of pump  10 =A, the inside volume of the distribution chambers  51 =B, the inside volume of pump  10  when collapsed=C, thus P 1 V 1 *P 2 V 2 =n. The pressure of pump  10  after compression is Pb=PaA/B+C. Therefore, an increase in the inside volume B of distribution chambers  51  will result in a corresponding decrease in the air pressure Pb of pressure accumulation chamber  6 .  
         [0026]    When through holes  52  and pump  10  are disposed in communication with an air passage  3   c,  air is permitted to be compressed out of pump  10  through air passage  3   c  to another air circulation area. This permits air cushion  1 A to improve the ventilation of the shoe.  
         [0027]    It is to be understood that the preferred embodiments of the invention described herein are for purposes of illustration only and that they are not intended to limit the scope of the disclosed invention which is set forth in the appended claims.