Patent Publication Number: US-2009239006-A1

Title: Air enclosure without heat resistant material and manufacturing of same

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 97110269 filed in Taiwan, R.O.C. on Mar. 21, 2008, the entire contents of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to an air enclosure and a method for manufacturing it, and more particularly to an air enclosure without a heat resistant material and a method for manufacturing it. 
     BACKGROUND 
     Generally, when an article is packed, a soft material such as foam or Styrofoam is used to provide the article with a cushioning protection. However, foam can be attached closely to a surface of the article, but mere impact protection is sub-optimal; the article is still frequently struck and damaged. Moreover, foam is difficult to deal with; it is accompanied by environmental protection issues. The Styrofoam may prevent an article from being damaged by shaking, but a bouffant volume of Styrofoam occupies a large volume, does not decompose easy, and will release poisonous gas after incineration, causing serious environmental pollution. Thus foam and Styrofoam cause environmental protection problems; Styrofoam is not an ideal cushioning material in the current culture of heightened environmental consciousness. 
     To solve the aforementioned problems, an air enclosure using a resin film as a material is developed; it is sealed by means of hot sealing to form an air cylinder and disposed with an air filling entrance. The air enclosure can be used as a cushioning material during an inner packing after being filled in the air cylinder via the air filling entrance, where a check valve will be disposed in the air enclosure to create an air lock. 
     Please refer to  FIGS. 1A to 1C .  FIGS. 1A to 1C  show an assembly structure of a shut-off valve of an air enclosure, and an apparatus for manufacturing an air enclosure with a switching valve disclosed by Taiwan Patent No. 587049. While a check valve is formed by means of hot sealing, a side bag sheet A 11  and valve sheets A 21  and A 22  are first stacked together, and then formed with a plurality of fixing sealing portions A 31  by means of hot sealing, thereby adhering the side bag sheet A 11  and the two valve sheets A 21  and A 22  together by means of hot sealing as  FIG. 1A  shows; furthermore, another side bag sheet A 12  is then stacked with them, front and rear sealing portions A 4  and a strengthening sealing portions A 32  are formed by adhering them all together by means of hot sealing, and an air inlet A 6  is formed between the two strengthening sealing portions A 32  as  FIG. 1B  shows; finally, left and right sealing portions A 5  are formed by means of hot sealing, and air cylinders A 8  are formed among the front and rear sealing portions A 4  and the left and right sealing portions A 5  as well as an air filling entrance A 7  is formed among one side of the strengthening sealing portions A 32  and the right and left sealing portions A 5  as  FIG. 1C  shows. Air in the fill passageway A 7  can then be moved into the air cylinders A 8  via the air inlets A 6 . The bag sheets A 11  and A 22  are caused to pull apart outward after air flows into the air filling passageway A 7 , but the two valve sheets will be moved with the bag sheet A 11  owing to the adhering of the three layers of the bag sheet A 11  and the two sheets of valve sheet A 21 , A 22  such that the air inlet A 6  cannot be pulled apart outward with the bag sheets A 11 , A 12  to open; this causes the air to stay in the air filling passageway A 7 , further compressing the two valve sheets A 21 , A 22  attaching to the bag sheet A 11  to shield the air inlet A 6  closely and prevent air from entering the air cylinder A 8  via the air inlet A 6 . 
     Please refer to  FIGS. 2A and 2B .  FIGS. 2A and 2B  show a continuously air-filling air enclosure disclosed by Taiwan Patent No. M306977. A heat resistant material B 10  is spread between two sheets of inner film B 11  and B 12  in advance, and the two sheets of inner film B 11  and B 12  are then stacked together between two sheets of outer film B 21  and B 22 ; hot sealing is carried out along hot sealing lines B 3  and B 4  to allow the two sheets of outer film B 21  and B 22  to be adhered to each other to form an air filling passageway B 9  and air inlets B 14  at places of the hot sealing line B 4  spread with the heat resistant material B 10 , and hot sealing is carried out along hot sealing lines B 4 , B 5 , B 6  and B 7  to allow the two sheets of outer film B 21  and B 22  to be adhered to each other to form an air cylinder B 8 . This method may solve the problem in the aforementioned invention patent of being unable to open the air inlet, but the heat resistant material must be spread between the two sheets of inner film in advance and the two sheets of inner film can then be stacked together. Hence, not only the material cost is increased but the process of spreading the heat resistant material is time and labor wasting; this prevents the effective reduction of the production cost of an air enclosure. 
     SUMMARY OF THE INVENTION 
     To improve an air inlet of an air enclosure and its manufacturing process, decreasing the labor and the material costs consumed by spreading a heat resistant material and in the meantime, allowing the air inlet to be opened effectively so as to enable the air filling to be continuous to save the air filling time, the present invention is proposed. 
     To achieve the objects mentioned above, the present invention proposes an air enclosure without a hear resistant material, including:
     two outer films, stacked together vertically;   two inner films, positioned between the two outer films;   at least one air cylinder, formed between the two outer films by means of hot sealing; and   at least one air inlet, formed between the two inner films by adhering the two outer films and the two inner films together by means of hot sealing after placing a heat resistant pad between the two inner films thereby allowing air to be filled in the air cylinder via the air inlet to cause the air cylinder to be filled with air and expanded to enable air in the air cylinder to compress the two inner films to cover the air inlet to shield the air cylinder.   

     The present invention also proposes a method for manufacturing an air enclosure without a heat resistant material, including the following steps:
     providing two inner films;   stacking two outer films together to allow the two inner films to be lain in between the two outer films;   placing at least one heat resistant pad between the two inner films;   adhering the two outer films to the two inner films by means of hot sealing to form at least one air inlet between the two inner films and at least one air cylinder between the two outer films;   taking out the heat resistant pad;   filling air into the air cylinder via the air inlet to allow the air cylinder to be filled with air and expanded; and   using air in the air cylinder to compress the two inner films to cover the air inlet to shield the air cylinder.   

     Where it is not necessary to spread a heat resistant material in advance according to the present invention, the two sheets of inner film are stacked together directly and the heat resistant pad is used to place in between the two inner films to form the air inlet by means of hot sealing thereby shortening the manufacturing process effectively and reducing the labor and the material costs substantially. In addition, when the two sheets of outer film are pulled apart, the air inlets formed by the inner films are opened automatically, air is filled into the plurality of air cylinders via the air inlets; it is unnecessary to position each air inlet while being filled with air, thus reducing the air filling time. Each air cylinder is independent and the cushioning effect is not influenced even if some air cylinders are broken. The air in the air cylinder compresses the inner films to cover the air inlet to shield the air cylinder creating an air lock. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be more fully understood by reference to the following description and accompanying drawings, in which: 
         FIGS. 1A to 1C  are schematic views of a conventional check valve while being manufactured; 
         FIG. 2A  is a cross sectional view of a conventional air enclosure; 
         FIG. 2B  is a plane view of a conventional air enclosure; 
         FIG. 3  is a perspective view, showing an air enclosure of a first embodiment according to the present invention after being filled with air; 
         FIG. 4  is a schematic view, showing an air enclosure of the first embodiment according to the present invention while being manufactured by inserting a heat resistant pad; 
         FIG. 5  is a plane view, showing an air enclosure of the first embodiment according to the present invention after being filled with air; 
         FIG. 6A  is a schematic view, showing a heat resistant pad of the first embodiment according to the present invention while being manufactured; 
         FIG. 6B  is a plane view, showing an air enclosure of the first embodiment according to the present invention before being filled with air; 
         FIGS. 7A and 7B  are cross sectional views, showing an air enclosure of the first embodiment while being manufactured by inserting a heat resistant pad; 
         FIGS. 8A and 8B  are schematic views, showing an air enclosure of a second embodiment while being manufactured by inserting a heat resistant pad; 
         FIG. 9  is a cross sectional view, showing an air enclosure of the second embodiment according to the present invention after being filled with air; 
         FIG. 10  is a plane view, showing an air enclosure of a third embodiment according to the present invention before being filled with air; and 
         FIGS. 11 and 12  are cross sectional views, showing an air enclosure of the third embodiment according to the present invention after being filled with air. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to  FIGS. 3 ,  4 ,  5 ,  6 A,  6 B,  7 A and  7 B.  FIG. 3  is a perspective view, showing an air enclosure of a first embodiment according to the present invention after being filled with air.  FIG. 4  is a schematic view, showing an air enclosure of the first embodiment according to the present invention while being manufactured by inserting a heat resistant pad.  FIG. 5  is a plane view, showing an air enclosure of the first embodiment according to the present invention after being filled with air.  FIG. 6A  is a schematic view, showing a heat resistant pad of the first embodiment according to the present invention while being manufactured.  FIG. 6B  is a plane view, showing an air enclosure of the first embodiment according to the present invention before being filled with air.  FIGS. 7A and 7B  are cross sectional views, showing an air enclosure of the first embodiment while being manufactured by inserting a heat resistant pad. 
     An air enclosure without a heat resistant material includes two sheets of outer film  2   a  and  2   b,  two sheets of inner film  1   a  and  1   b,  an air filling passageway  9 , a plurality of air cylinders  11  and a plurality of air inlets  2   d.    
     The two sheets of outer film  2   a  and  2   b  are stacked together vertically. 
     The two sheets of inner film  1   a  and  1   b  are lain in between the two sheets of outer film  2   a  and  2   b,  lengths of the inner films  1   a  and  1   b  are shorter than a length of the outer film  2   a  or  2   b,  and top ends of the two sheets of inner film are lower than top ends of the two sheets of outer film  2   a  and  2   b.    
     A heat resistant pad  8  is placed between the two sheets of inner film  1   a  and  1   b;  hot sealing is carried out along a hot sealing line  4 , the two sheets of inner film  1   a  and  1   b  are still not adhered to each other to form a plurality of air inlet  2   d  and in the meantime, hot sealing is used to generate a plurality of hot sealing portions  2   c  thereby adhering the outer  2   a  to the inner film  1   a  and the outer film  2   b  to the inner film  1   b,  where the heat resistant pad  9  is disposed with a plurality of projecting portions  81 . The plurality of projecting portions  81  of the heat resistant pad  8  are placed between the two sheets of inner film  1   a  and  1   b,  and the two sheets of outer film  2   a  and  2   b  and the two sheets of inner film  1   a  and  1   b  are adhered to each other by means of hot sealing along the hot sealing line  4  to form the plurality of air inlets  2   d.    
     Hot sealing is carried out along a hot sealing line  3  to allow the two sheets of outer film  2   a  and  2   b  to be adhered to each other to form an air filling passageway  9  between the hot sealing lines  3  and  4 , where the air filling passageway  9  includes an air filling entrance  9   a  connected to the outside; hot sealing is carried out along hot sealing lines  5  and  6  to allow the two sheets of outer film  2   a  and  2   b  to be adhered to each other to form a plurality of air cylinders  11  among the hot sealing lines  4 ,  5  and  6 , where the air cylinder  11  is used for storing air, and the air inlet  2   d  communicates the air cylinder  11  with the air filling passageway  9 . 
     Air entering the air filling entrance  9   a  expands the air filling passageway  9  to cause the two sheets of outer film  2   a  and  2   b  to be pulled apart outward, and the two sheets of inner film  1   a  and  1   b  can be pushed apart by the hot sealing portions  2   c  positioned in the air filling passageway  9  to open outward because the outer film  2   a  and the inner film  1   a  together with the outer film  2   b  and the inner film  1   b  are adhered to each other by means of hot sealing thereby allowing the two sheets of inner film  1   a  and  1   b  not adhered to each other to be pull apart outward to automatically open each air inlet  2   d  connected to the air filling passageway  9 , as  FIG. 5  shows. The air in the air filling passageway  9  can be filled into each air cylinder  11  to cause it to expand via each air inlet  2   d;  it is unnecessary to carry out the air filling after positioning each air inlet  2   d,  thus reducing air filling time; further, the entire cushioning effect is not influenced even if some air cylinders  11  are broken because each air cylinder is independent. 
     After air enters the air cylinder  11  via the air inlet  2   d,  internal air pressure of the air cylinder  11  compresses the inner film  1   a  or  1   b  to cover the air inlet  2   d  and shield the air cylinder  11  so as to create an air lock. 
     A gradually contracted air passageway  13  connected to the air inlet  2   d  may be disposed in advance in the air cylinder  11 . One end of the air passageway  13  connected with the air inlet  2   d  is wider than another end thereof to allow the air in the air inlet  2   d  to enter easily but not escape easily. In addition, a curved air passageway  13  connected with the air inlet  2   d  may also be disposed in advance in the air cylinder  11 . A curved portion of the air passageway  13  is compressed tightly to create an air lock while the internal pressure of the air cylinder  11  increases. 
     In addition, if the inner film  1   a  and the outer film  2   a  are adhered to each other by means of hot sealing, the two sheets of inner film  1   a  and  1   b  are side-attached to the outer film  2   a  while being compressed as  FIG. 5  show; if the inner film  1   b  and the outer film  2   b  are adhered to each other by means of hot sealing, the two sheets of inner film  1   a  and  1   b  are side-attached to the outer film  2   b  while being compressed. Such an air enclosure where the two sheets of inner film  1   a  and  1   b  are compressed by the air in the air cylinder  11  to side-attach onto the outer film  2   a  or  2   b  is referred to as a “two sheets side-attachment type” air enclosure. Furthermore, the air enclosure where the two sheets of inner film are not side-attached to the outer film  2   a  or  2   b  but suspended in the air cylinder  11  while being compressed is referred to as a “two sheets wall-hanging type” air enclosure. 
     Please refer to  FIGS. 8A ,  8 B and  9 .  FIGS. 8A and 8B  are schematic views, showing an air enclosure of a second embodiment while being manufactured by inserting a heat resistant pad.  FIG. 9  is a cross sectional view, showing an air enclosure of the second embodiment according to the present invention after being filled with air. 
     In the present embodiment, top ends of the two sheets of inner film  1   a  and  1   b  are aligned with top ends of the two sheets of outer film  2   a  and  2   b,  and hot sealing is used to generate hot sealing portions  2   c  thereby adhering the outer film  2   a  to the inner film  1   a  and the outer film  2   b  to the inner film  1   b,  where the hot sealing portions  2   c  may be a plurality of hot sealing points as  FIG. 8A  shows, or may be a plurality of hot sealing lines as  FIG. 8B  shows, but it is not limited to these. 
     Furthermore, when the hot sealing is carried out along the hot sealing line  3 , the two sheets of inner film  1   a  and  1   b  are adhered to each other to form an air filling passageway  9  between the hot sealing lines  3  and  4 . When the air filling passageway  9  is filled with air and expanded, it will drive the two sheets of inner film  1   a  and  1   b  to pull apart outward to automatically open each air inlet  2   d  connected with the air filling passageway  9  to allow the air in the air filling passageway  9  to be filled into each air cylinder  11  to cause it to be filled with air and expanded via each air inlet  2   d.    
     Please refer to  FIGS. 10 ,  11  and  12 .  FIG. 10  is a plane view, showing an air enclosure of a third embodiment according to the present invention before being filled with air.  FIGS. 11 and 12  are cross sectional views, showing an air enclosure of the third embodiment according to the present invention after being filled with air. 
     The present invention may further includes two sheets of auxiliary film  7   a  and  7   b  positioned between the two sheets of inner film  1   a  and  1   b.  Two sides of the two sheets of inner film  1   a  and  1   b  and two sides of the auxiliary film  7   a  and  7   b  are adhered to each other by means of hot sealing along an auxiliary hot sealing line  42 , and the projecting portions  81  of the heat resistant pad  8  are then placed between the two sheets of auxiliary film  7   a  and  7   b.  Thereafter, the two sheets of inner film  1   a  and  1   b  together with the two sheets of auxiliary films  7   a  and  7   b  are adhered to each other by means of hot sealing along a hot sealing line  41  to form a plurality of auxiliary air inlet  7   d  between the two sheets of auxiliary film  7   a  and  7   b.    
     Wherein, the two sheets of auxiliary film  7   a  and  7   b  are disposed at a bottom place between the two sheets of inner film  1   a  and  1   b,  i.e. a position below the hot sealing line  4  as  FIG. 11  shows; they may also disposed at a middle position between the two sheets of inner film  1   a  and  1   b,  i.e. parts of the auxiliary films  7   a  and  7   b  are positioned above the hot sealing line  4 , and other parts thereof are positioned below the hot sealing line  4  as  FIG. 12  shows. 
     Where the air filling passageway  9  is not disposed in the present embodiment, a user may directly and manually pull the two sheets of inner film  1   a  and  1   b  apart outward and in the meantime, the two sheets of auxiliary film  7   a  and  7   b  not adhered to each other are caused to pull apart outward to automatically open the auxiliary air inlet  7   d,  and an air filling tool (not shown in the figure) is then used to do the air filling. Thereafter, air can be filled in each air cylinder  11  via the air inlet  2   d  and the auxiliary air inlet  7   d.    
     Although the present embodiment assumes for the sake of example that the side of the air cylinder  11  is not disposed with the air filling passageway  9 , it is not limited to this. The structure may be adjusted depending on practical requirements. For example, the two sheets of outer film  2   a  and  2   b  are adhered to each other or the two sheets of inner film  1   a  and  1   b  to each other by means of hot sealing to form the air filling passageway  9 ; air entering the air filling entrance  9   a  expands the air filling passageway  9  to cause the two sheets of outer film  2   a  and  2   b  to be pulled apart outward. Because the outer film  2   a  and the inner film  1   a  as well as the outer film  2   b  and the inner film  1   b  are adhered to each other by means of hot sealing, the two sheets of inner film  1   a  and  1   b  can be driven to open outward through the hot sealing portion  2   c  positioned in the air filling passageway  9  thereby allowing the two sheets of inner film  1   a  and  1   b  not adhered to each other to be pulled apart outward to automatically open each air inlet  2   d  connected with the air filling passageway  9  and in the meantime, allowing the two sheets of auxiliary film  7   a  and  7   b  not adhered to each other to be pulled apart outward to automatically open the auxiliary air inlet  7   d.  The air in the air filling passageway  9  can be filled in each air cylinder  11  to cause it to be filled with air and expanded via the air inlet  2   d  and the auxiliary air inlet  7   d.    
     In the present embodiment, the two sheets of auxiliary film  7   a  and  7   b  are further disposed between the two sheets of inner film  1   a  and  1   b  thereby allowing high pressure air to be filled in the air cylinder  11  to prevent high pressure air from causing the two sheets of inner film  1   a  and  1   b  to be broken during the air filling to increase air filling efficiency. 
     A method for manufacturing an air enclosure without a heat resistant material according to the present invention, includes the following steps: 
     Step  1 : providing two sheets of inner film  1   a  and  1   b;    
     Step  2 : stacking two sheets of outer film  2   a  and  2   b  to allow the two sheets of inner film  1   a  and  1   b  to be lain in between the two sheets of outer film  2   a  and  2   b;    
     Lengths of the two sheets of inner film  1   a  and  1   b  are shorter than lengths of the two sheets of outer film  2   a  and  2   b,  and top ends of the two sheets of inner  1   a  and  1   b  are lower than top ends of the two sheets of outer film  2   a  and  2   b,  or aligned with the top ends of the two sheets of outer film  2   a  and  2   b.    
     Step  3 : placing a heat resistant pad  8  between the two sheets of inner film  1   a  and  1   b;    
     The heat resistant pad  8  is disposed with a plurality of projecting portions  81 , and the plurality of projecting portions  81  of the heat resistant pad  8  are placed between the two sheets of inner film  1   a  and  1   b.    
     Step  4 : adhering the two sheets of outer film  2   a  and  2   b  and the two sheets of inner film  1   a  and  1   b  to each other by means of hot sealing to form a plurality of air inlets  2   d  and form a plurality of air cylinders  11  between the two sheets of outer film  2   a  and  2   b.    
     When the top ends of the two sheets of inner film  1   a  and  1   b  are lower than the top ends of the two sheets of outer film  2   a  and  2   b,  the two sheets of outer film  2   a  and  2   b  as well as the two sheets of inner film  1   a  and  1   b  adhered to each other by means of hot sealing along a hot sealing line  4  to form a plurality of air inlets  2   d  and in the meantime, generate a hot sealing portion  2   c  by means of hot sealing, thereby adhering the outer film  2   a  to the inner film  1   a  and the outer film  2   b  to the inner film  1   b;  the two sheets of outer film  2   a  and  2   b  are adhered to each other by means of hot sealing along a hot sealing line  3  to form an air filling passageway  9  between the hot sealing lines  3  and  4 , and the air filling passageway  9  includes an air filling entrance  9   a  connected to the outside. 
     When the top ends of the two sheets of inner film  1   a  and  1   b  are aligned with the top ends of the two sheets of outer film  2   a  and  2   b,  hot sealing portions  2   c  are generated by means of hot sealing thereby adhering the outer film  2   a  to the inner film  1   a  and the outer film  2   b  to the inner film  1   b,  where the hot sealing portions  2   c  may be a plurality of hot sealing points or hot sealing lines. The two sheets of outer film  2   a  and  2   b  as well as the two sheets of inner film  1   a  and  1   b  are adhered to each other by means of hot sealing along a hot sealing line  4  to form a plurality of air inlets  2   d;  the two sheets of inner film  1   a  and  1   b  are adhered to each other by process hot sealing along a hot sealing line  3  to form an air filling entrance  9  between the hot sealing lines  3  and  4 , and the air filling passageway  9  includes an air filling entrance  9   a  connected to the outside. 
     Hot sealing is carried out along hot sealing lines  5  and  6  to allow the two sheets of outer film  2   a  and  2   b  to be adhered to each other to form air cylinders  11  among the hot sealing lines  4 ,  5  and  6 , the air cylinder  11  is used for storing air, and the air inlet  2   d  communicates the air cylinder  11  with the air filling passageway  9 . In addition, the air filling passageway  9  is positioned at one side of the air cylinder  11 . 
     Step  5 : taking out the heat resistant pad  8 ; 
     Step  6 : filling air into the air cylinder  11  via the air inlet  2   d  to allow the air cylinder  11  to be filled with air and expanded. 
     When the air filling passageway  9  is formed by adhering the two sheets of outer film  2   a  and  2   b,  air entering the air filling entrance  9   a  expands the air filling passageway  9  to cause the two sheets of outer film  2   a  and  2   b  to be pulled apart outward. Because the outer film  2   a  and the inner film  1   a  as well as the outer film  2   b  and the inner film  1   b  are adhered to each other by means of hot sealing, the two sheets of inner film  1   a  and  1   b  can be pushed open outward through the hot sealing portion  2   c  positioned in the air filling passageway  9 , thereby allowing the two sheets of inner film  1   a  and  1   b  not adhered to each other to be pulled apart outward to automatically open each air inlet  2   d  connected with the air filling passageway  9 . The air in the air filling passageway  9  can be filled in each air cylinder  11  via each air inlet  2   d  to cause the air cylinder  11  to be filled with air and expanded. If the air cylinder passageway  9  is formed by adhering the two sheets of inner film  1   a  and  1   b  to each other, air entering the air filling entrance  9   a  expands the air filling passageway  9  to drive the two sheets of inner film  1   a  and  1   b  to pull apart outward to automatically open each air inlet  2   d  connected to the air filling entrance  9  to allow the air in the air filling passageway  9  to be filled in each cylinder  11  via each air inlet  2   d  to cause the air cylinder to be filled with air and expanded. 
     Step  7 : using the air in the air cylinder  11  to compress the two sheets of inner film  1   a  and  1   b  to cover the air inlet  2   d  and shield the air cylinder  11 . 
     After air enters the air cylinder  11  via the air inlet  2   d,  internal air pressure of the air cylinder  11  compresses the inner film  1   a  or  1   b  to cover the air inlet  2   d  and shield the air cylinder  11  so as to create an air lock. In this case, when the two sheets of inner film  1   a  and  1   b  are compressed they can be side-attached to the one sheet of outer film  2   a  or  2   b,  or not be side-attached to the outer film  2   a  or  2   b  but suspended in the air cylinder  11 . 
     Furthermore, the method according to the present invention may further include after Step  1 : providing two sheets of auxiliary film  7   a  and  7   b  to allow the two sheets of auxiliary film  7   a  and  7   b  to be lain in between the two sheets of inner film  1   a  and  1   b.  Therefore, two sides of the two sheets of inner film  1   a  and  1   b  and two sides of the two sheets of auxiliary film  7   a  and  7   b  are adhered to each other in advance by means of hot sealing along an auxiliary hot sealing line  42  in Step  2 , and the plurality of projecting portions  81  of the heat resistant pad  8  are then placed between the two sheets of auxiliary film  7   a  and  7   b.  The two sheets of inner film  1   a  and  1   b  as well as the two sheets of auxiliary film  7   a  and  7   b  are adhered to each other by means of hot sealing along an auxiliary hot sealing line  41  to form a plurality of auxiliary air inlets  7   d  between the two sheets of auxiliary film  7   a  and  7   b.  In this case, the two sheets of auxiliary film  7   a  and  7   b  are disposed at a bottom place between the two sheets of inner film  1   a  and  1   b,  i.e. a position below the hot sealing line  4 ; they may also be disposed at a middle position between the two sheets of inner film  1   a  and  1   b,  i.e. parts of the auxiliary films  7   a  and  7   b  are positioned above the hot sealing line  4 , and other parts thereof are positioned below the hot sealing line  4 . 
     According to the present invention, the two sheets of inner film are stacked together directly, it is unnecessary to spread in advance a heat resistant material between the two sheets of inner film, a heat resistant pad is placed between the two sheets of inner film and hot sealing is carried out to adhere the two sheets of inner film to each other to form air inlets so as to shorten effectively the manufacturing process and reduce substantially labor and material costs. In addition, according to the present invention, the air inlets can be opened automatically while the air filling is being processed so as to fill the plurality of air cylinders with air via the air inlets; it is not necessary to position each air inlet during the air filling, thus reducing air filling time. Each air cylinder is independent; the cushioning effect is not influenced even if some air cylinders are broken. The air in the air cylinder compresses the inner films to cover the air inlet to shield the air cylinder; the air can be prevented from leaking to attain to the air locking effect. Moreover, the air compresses the curved portion of the air passageway when the internal air pressure of the air cylinder increases to attain to the air locking effect too. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the scope of the general inventive concept as defined by the appended claims and their equivalents.