Abstract:
A side impact air bag apparatus located in a seat back of a vehicle for directly initiating an air bag longitudinally before completely inflating the bag in the width direction. The side impact air bag has a casing with an interior, a support for an inflator and a bag enclosing the inflator. The bag is capable of direct inflation longitudinally before completely inflating in the width direction. The bag is arranged inside the casing to have, a forward middle portion associated with the inflator, a right base cloth portion extending from the right of the forward middle portion and having first angled bellow folds of cloth, a left base cloth portion extending from the left of the forward middle portion and having second angled bellow folds of cloth, and an interior gas flow passage extending between the forward middle portion and the inflator, such that gas generated by the inflator easily reaches the forward middle portion through the interior gas flow passage and pushes the forward middle portion out in a longitudinal direction before the first bellow folds and the second bellow folds are inflated.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an air bag apparatus in which an air bag, disposed in the inside of a seat back is inflated in a cabin upon a vehicle side collision thereby protecting a side portion of an occupant. 
     An air bag apparatus for protecting a side portion of an occupant in a car is disclosed, for example, in Japanese Patent Unexamined Publication No. Hei. 10-53086 or in Japanese Patent Unexamined Publication No. Hei. 3-108564. Generally, such an air bag apparatus is provided with an air bag module which has a folded air bag, an inflator, etc. A conventional air bag apparatus  200  will be described in brief with reference to FIG.  3 . FIG. 3 is a schematic perspective view showing an air bag apparatus disposed in a seat back and a state in which the air bag is inflated. 
     The aforementioned air bag module  201  is received in a module casing  202 . The air bag module  201  is set up together with the module casing  202  in a seat back S 2 . When a car is run into at its side, that is, upon a side collision, a sensor detects this collision and a gas is generated by an inflator  201   a  thereby unfolding an air bag  204  so that an occupant is protected. 
     FIG. 1 is a sectional view taken along the line X—X in FIG.  3  and showing the inside of the module casing  202 . In the conventional air bag module  201 , the air bag  204  is set up as shown in FIG.  1 . 
     That is, the air bag  204  is folded stepwise, while alternately turning back at opposite ends was repeated to a forward end portion  204   b  after a holder  201   b  for holding the inflator  201   a  was enclosed in a base end portion  204   a.    
     When the air bag  204  is inflated, a propellant in the inflator  201   a  is ignited so that a gas is generated to be fed into the air bag  204  (see the arrows in FIG.  1 ). As a result, the air bag  204  is inflated thereby forcing a cover portion  202   a  of the module casing  202  to open as indicated by the two-dot chain line in FIG.  1 . The air bag  204  is further inflated continuously so as to be inflated while rupturing a seam portion in the right portion of the seat back S 2  (see FIG.  3 ). FIG. 2 is a side view typically showing the inflating process of the air bag  104 . FIG. 2A shows an initial state of inflating; FIG. 2B shows a state after a predetermined time is passed from the start of inflating; and FIG. 2C shows a state after inflation is completed. 
     In the conventional air bag module  202 , the air bag  204  is folded alternately so that the opposite sides of the folded air bag  204  superimpose on one another completely. Therefore, it is inevitable that the air bag  204  must be inflated gradually from the base end portion  204   a  side. There is the possibility that inflating might be obstructed a little by a certain time lag with respect to the time required for gas to reach the forward end portion  204   b  of the air bag  204 , or obstructed by failure of the folds of the air bag  204  in the middle of inflating. 
     With respect to the inflating of the air bag  204 , it is very important that the air bag can be inflated rapidly to respond instantaneously to a car side collision. Accordingly, not only the inflating of the air bag  204  needs to be performed as rapidly as possible but also secure inflation of the air bag  204  needs to be attained. 
     In addition, such an air bag apparatus gives priority to the protection of the chest or head of an occupant. Accordingly, the air bag in the air bag apparatus is required to be inflated in a comparatively high position, such as the chest level, of the occupant. To unfold the bag in a comparatively high position, such as at the chest level of the occupant, To unfold the bag in a comparatively high position, such as at the chest level of the occupant, conceivably the module is received in a high position of the seat back. 
     A side portion of the seat back is, however, generally designed so as to be thinner higher up the seat back for the purpose of the occupant&#39;s comfort when riding. Accordingly, if the module is received in a high position of the side portion of the seat back, there is a disadvantage in spoiling the occupant&#39;s comfortable feeling when riding. Accordingly, the module is required to be received in a position as low as possible in the side portion of the seat back. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to inflate the air bag of the present invention more quickly and to prevent inflating failure from occurring. 
     In order to solve the above problem according to a first aspect of the present invention, there is provided an air bag apparatus comprising an air bag folded and disposed in a seat back, the air bag being adapted to be inflated with a gas generated by an inflator thereby protecting an occupant, wherein, the air bag includes a pair of base cloth portions which superimpose on each other so as to be shaped like a bag, the pair of base cloth portions being formed so that, when the air bag is folded, the pair of base cloth portions are folded individually in the form of bellows so as to form a gas flow passage between the pair of base cloth portions. 
     By the aforementioned means, the gas generated by the inflator is made to reach the forward end portion of the air bag through the passage easily. Accordingly, not only inflation of the air bag is performed rapidly but also inflating failure is effectively prevented from occurring. 
     In addition to this, it is also an object of the present invention to make it possible to protect a comparatively high position, such as the chest portion, of an occupant, even in the case where a module is received in a low position of a side portion of a seat back so as not to spoil occupant&#39;s comfort when riding. 
     In order to solve the above problem, according to a second aspect of the present invention, there is provided an air bag apparatus comprising an air bag, disposed in a side portion of a seat back, in a condition such that it is attached to a module and folded, the air bag being adapted to be inflated with a gas generated by an inflator so as to be inflated between an occupant and an inner surface of a side portion of a vehicle body in the event of a vehicle collision, wherein, the air bag includes a base end portion and a protective portion which are designed so that the base end portion is adapted to be inflated directly in an upward direction, more upward than a direction perpendicular to a longitudinal direction of the module, whereas the protective portion is adapted to be inflated forward. 
     According to the present invention, the module is received in a low position of the side portion of the seat back so that a comparatively high position, such as the chest, of the occupant can be protected securely without spoiling occupant&#39;s comfort when riding. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view taken along the line X—X in FIG. 3 in the case where a conventional air bag apparatus is disposed. 
     FIG. 2 is a side view showing the inflation of the air bag in the conventional air bag apparatus. FIG. 2A shows an initial state of inflating; FIG. 2B shows a state after a predetermined time is passed from the start of inflating; and FIG. 2C shows a state after inflating is completed. 
     FIG. 3 is a schematic perspective view showing an air bag apparatus, according to the present invention, disposed in a seat back and a state in which the air bag is inflated. 
     FIG. 4 is a plan view of an inflated state of the air bag viewed from the top. 
     FIG. 5 is a perspective view of the module casing which is set up in the seat back so the air bag can be received in the module casing. 
     FIG. 6 is a sectional view taken along the line Z—Z in FIG.  5 . 
     FIGS. 7A-7C are side views of a process of folding the air bag. 
     FIGS. 8A-8C are sectional views taken along the line W—W in FIGS. 7A-7C respectively. 
     FIGS. 9A-9C are side views showing the inflation of the air bag in the air bag apparatus. FIG. 9A shows an initial state of inflating; FIG. 9B shows a state after a predetermined time is passed from the start of inflating; and FIG. 9C shows a state after inflating is completed. 
     FIG. 10 is a perspective view of a seat equipped with an air bag apparatus according to the present invention. 
     FIG. 11 is a plan view showing a state in which the air bag is inflated. 
     FIG. 12 is a sectional view taken along the line XII—XII in FIG.  10 . 
     FIG. 13 is a side view of the air bag apparatus according to the present invention. 
     FIG. 14 is a sectional view taken along the line XIV—XIV in FIG.  13 . 
     FIG. 15 is a side view showing an inflated state of the air bag. 
     FIG. 16 is a side view showing an inflated state of the air bag and apparatus according to the present invention. 
     FIGS. 17A-17C are side views showing a process of folding the air bag. 
     FIGS. 18A-18C are plan views showing a method of folding the air bag. 
     FIG. 19 is a plan view of the inflated air bag. 
     FIGS. 20A-20C are views showing the inflation of the air bag. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described specifically below with reference to the drawings. 
     An air bag apparatus  1  according to a first embodiment is disposed in the inside of a side portion of a seat back S 2  in the same manner as in FIG. 3, referred to in the conventional technique. Referring now to FIGS. 3 and 4, the arrangement of the air bag apparatus  1  and a front seat S on the right side of a car will be described. FIG. 4 is a plan view of an inflated state of the air bag  6  viewed from the top. 
     As shown in FIG. 3, the front seat S on the right side of the car is constituted by a seat cushion S 1  disposed substantially horizontally, a seat back S 2  extending upward from a rear end of the seat cushion S 1 , and a head rest S 3  provided at an upper end of the seat back S 2 . 
     As shown in FIG. 4, a center pillar CP faces a right side surface of the seat back S 2 . A front door FD is disposed in front of the center pillar CP. An air bag module  3 , received in a module casing  4 , is positioned in the inside of the right side of the seat back S 2  of the front seat S. Incidentally, in the setting of the air bag module  3 , the module casing  4  is placed with a cover portion  4   c  which turns to the outer side (right side in FIG. 4) and with a hinge portion  4   b  which turns to the rear side. 
     As shown in FIG. 4, a frontal center portion of the seat back S 2  is covered with a first coating material  20  and left and right, opposite side and upper portions of the first coating material  20  are covered with a second coating material  21 . Further, left and right, opposite side and upper surfaces of the seat back S 2  connected to the second coating material  21  are covered with a third coating material  22 . Further, a rear surface of the seat back S 2  is covered with a fourth coating material  23 . The respective coating materials  20 ,  21 ,  22  and  23  are sewn together with one another in side edge portions. A side seam portion  25  is formed particularly in a place where the second and third coating materials  21  and  22  are sewn together. 
     When the air bag module  3  is operated, the air bag  6  is inflated thereby forcing the cover portion  4   c  of the module casing  4  to open and then break and open the side seam portion  25  of the seat back S 2 . The air bag  6  is further inflated continuously, so that the air bag  6  is inflated obliquely forward so as to come between the right side of the occupant sitting on the front seat S and the left side of the center pillar CP and the front door FD. 
     Next, the structure of the air bag module  3  will be described with reference to FIGS. 5 and 6. FIG. 5 is a perspective view of the module casing attached into the seat back in a state in which the air bag module can be received in the module casing; and FIG. 6 is a sectional view taken along the line Z—Z in FIG.  5 . 
     As shown in FIG. 6, a holder  31  of a metal has a body portion  31   a  substantially J-shaped in a sectional view, and a pair of clamp portions  31   b ,  31   b  extending from one side edge of the body portion  31   a  and shaped so as to be curved substantially circularly. Further, as shown in FIG. 5, the pair of clamp portions  31   b  are formed in upper and lower positions along a longitudinal direction of the body portion  31   a.    
     A substantially cylindrical inflator  32  containing a propellant is fitted into a circular sectional portion which is formed by the body portion  31   a  and the pair of clamp portions  31   b ,  31   b . The inflator  32  is fastened to the holder  31  by bolts  14 ,  14  and nuts  15 ,  15 , so as to be held while being integrated with the holder  31 . The integrated inflator  32  is enclosed in a base end portion  6   a  of the air bag  6 . A forward end portion  6   b  of the air bag  6  is folded. A combination of the folded air bag  6 , the inflator  32 , etc. as described above is the air bag module  3 . 
     The air bag module  3  is received in the inside of the module casing  4 , integrally formed from a synthetic resin. The module casing  4  has a tray-like body portion  4   a  which opens to the right side of the car body, and a cover portion  4   c  connected to a rear edge of the body portion  4   a  through a hinge portion  4   b . When five stoppage teeth  4   d ,  4   d , . . . provided in upper, front and lower edges of the body portion  4   a  are fitted into five stoppage cavities  4   e ,  4   e  . . . provided in upper, front and lower edges of the cover portion  4   c  respectively, the cover portion  4   c  is fixed so as to cover an opening of the body portion  4   a.    
     Further, the aforementioned air bag module  3  is attached, together with the module casing  4 , to an air bag module attachment bracket  12  by bolts  14 ,  14  and nuts  16 ,  16 . Incidentally, the air bag module attachment bracket  12  is fixed to a pipe frame which serves as a skeleton of the seat back S 2 , so that the air bag module  3  is fastened in a predetermined position. 
     Incidentally, in FIG. 5, the reference numeral  5  designates a harness for supplying an electric current to an igniter  32   a ; and  4   f  designates a holding cover portion for holding and protecting the harness  5 . 
     Folding of the air bag  6  at the time of formation of the air bag module  3  has been already described. Folding in this embodiment is, however, intrinsically different from folding in the conventional technique. Hence, folding of the air bag  6  will be described specifically with reference to FIGS. 6,  7  and  8 . FIGS. 7 and 8 show in a stepwise manner a process of folding the air bag. FIG. 7 is a side view of the air bag; and FIG. 6 is a sectional view taken along the line W—W in FIG.  7 . FIGS. 8A,  8 B and  8 C correspond to FIGS. 7A,  7 B and  7 C respectively. 
     The air bag  6  according to this embodiment is made from a piece of cloth shaped like a flat bag by folding the piece of cloth in two at its center and sewing its superimposed on circumferential edges together. Respective portions superimposed on each other so as to serve as sides of the bag are equivalent to the “base cloth portions” of the claims. In FIG. 6, the base cloth portion, designated by the reference numeral  36 , is an outer side (right side) base cloth portion and the base cloth portion, designated by the reference numeral  37 , is an inner side (left side) base cloth portion. Alternatively, the base cloth portions  36  and  37  may be formed by superimposing two independent pieces of cloth and sewing their circumferential edges together so as to be shaped like a bag or by use of cloth initially shaped like a bag without the necessity of sewing. 
     As shown in FIG. 6, the inflator  32 , etc. are enclosed in the base end portion  6   a  of the air bag  6 . Base portions  36   a  and  37   a  of the pair of base cloth portions  36  and  37  are put between the body portion  31   a  of the holder  31  and a side plate  33  and fastened and fixed by bolts  14 ,  14 . The base portion  36   a  of the base cloth portion  36  goes round by a rear surface of the inflator  32  from the inner side (left side in FIG. 6) to the outer side (right side in FIG. 6) of the car body so as to enclose the inflator  32  at about 360°. The position where the inflator  32  is enclosed in the base portion  36   a  is a point “a”. The front side extending forward from the point a is a foldable portion  36   b . On the other hand, the base portion  37   a  of the base cloth portion  37  on the right side of the car body extends forward along the inner side (left side in FIG. 6) of the body portion  31   a , turns back around a point “b” at the front end of the body portion  31   a  and returns forward at a point “c” which is a position in front of the inflator  32 . That is, the front side of the air bag  6  returned at the point c is a foldable portion  37   b.    
     Further, a portion of from the point b to the point c in the base cloth portion  37  (on the left side in FIG. 6) of the air bag  6  is disposed so as to be along the right surface of the body portion  31   a  of the holder  31 , so that the portion is provided as a surplus portion “b˜c.” When the air bag  6  is inflated, the surplus portion b˜c first rotates counterclockwise around the point b so as to be widened. As a result, the air bag  6  can be inflated rightward (laterally outward) easily. Accordingly, both the opening of the module casing  4  and the rupture of the side seam portion  25  (see FIG. 4) can be performed accurately. 
     As shown in FIGS. 7A and 8A, the foldable portions  36 B and  37 B of the inflated air bag  6  are folded individually from the front side to the rear side in the form of bellows. Further, as shown in FIG. 6, respective turns which form the bellows are provided so that the left and right foldable portions  36   b  and  37   b  do not engage with each other. Thus, a predetermined passage “R” is formed near the center. The passage R serves as a route for leading the gas from the inflator  32  to the forward end portion  6   b  of the air bag  6 . After the air bag  6  is folded up to a position shown in FIGS. 7B and 8B, that is, up to a position where the air bag module  3  is enclosed, upper and lower portions of the folded air bag  6  are bent downward and upward respectively (see FIG.  7 ( c )) so that the vertical height of the air bag  6  is reduced (see the arrow in FIG.  7 ( b )). After the folding, the folded air bag  6  is further bent in directions of the arrows in FIG. 8B, that is, laterally opposite half portions of the air bag  6  are squashed so as to fall forward so that the lateral width of the air bag  6  is reduced. 
     The folded air bag  6  is then packed in a protective cover compactly so that the air bag  6  does not come apart from the inflator  32 , the holder  31 , etc. As shown in FIG. 8C, the packed air bag  6  is received in the module casing  4 . The protective cover never disturbs the inflation of the air bag  6  because the protective cover is ruptured easily. 
     Further, when the air bag  6  is folded while the passage R is formed in the manner as described above in this embodiment, the gas being sent from the inflator  32  pushes out the forward end portion  6   b  of the air bag  6  before the respective foldable portions  36   b  and  37   b  are inflated. As a result, not only the air bag  6  is inflated more quickly but also inflating failure is effectively prevented from occurring. 
     The operation of the air bag apparatus according to this embodiment will be described below. 
     When the inflator  32  generates a gas in a vehicle collision, the air bag  6  is inflated in the inside of the module casing  4 . When an inflating pressure of the air bag  6  acts on the cover portion  4   c  of the module casing  4 , the stoppage teeth  4   d ,  4   d  . . . are disengaged from the stoppage cavities  4   e ,  4   e  . . . As a result, the cover portion  4   c  rotates around the hinge portion  4   b  (see the chain line in FIG.  6 ), so that the body portion  4   a  is opened. Further, as shown in FIG. 4, when a pressure for opening the cover portion  4   c  is transmitted to the third coating material  22  of the seat back S 2 , the side seam portion  25  is ruptured so that the second coating material  21  and the third coating material  22  are separated from each other. As a result, the air bag  6 , passed through a gap between the second coating material  21  and the third coating material  22 , is inflated obliquely forward, in a top view, so as to be along both the center pillar CP and the front door FD. 
     FIG. 9 is a view showing the inflation of the air bag  6 . As shown in FIG. 5, the air bag  6  is folded so that the gas passage R is formed in the center. Accordingly, the gas generated by the inflator  32  directly strikes the forward end portion  6   b  of the air bag  6 . As a result, the air bag  6  begins to be inflated vertically and longitudinally as shown in FIG.  9 A. 
     Further, the air bag  6  is inflated evenly as a whole as shown in FIG.  9 B. As a result, the air bag  6  goes into a perfectly inflated state quickly as shown in FIG.  9 C. The perfectly inflated air bag  6  protects the occupant&#39;s chest, or the like, securely. Incidentally, since the air bag  6  is inflated longitudinally directly, the air bag  6  can be inflated more quickly than the conventional air bag. 
     A second embodiment of the present invention will be described specifically below with reference to the drawings. 
     As shown in FIGS. 10 and 11, a right front seat S in a car is constituted by a seat cushion  1  disposed substantially horizontally, a seat back  102  extending rear upward from a rear end of the seat cushion  101 , and a head rest  103  provided at an upper end of the seat back  102 . A center pillar  104  faces a right side surface of the seat back  102 . A front door  105  is disposed in front of the center pillar  104 . A module “M” is received in the inside of the right side of the seat back  102  of the front seat S. When the module M is operated, an air bag  106  ruptures seam portions of the seat back  102  and forces them to open. Then, the air bag  106  is inflated obliquely forward so as to come between the right side of the occupant sitting on the front seat S and the left side of the center pillar  104  and the front door  105 . 
     As shown in FIG. 12, both a metal module-attachment bracket  112 , extending in the frontward direction of the car body and a metal retainer  113 , extending in the inward direction of the car body, are fixed by welding to a pipe frame  111  extending vertically along a right edge of the seat back  102 . The module M is fixed to the right side of the module-attachment bracket  112  by two bolts  114 ,  114  and two nuts  115 ,  115  (see FIG.  14 ). 
     Further, a shape-retaining material  116  constituted by a rough blanket extends from a front surface of the module M to a thickwise middle portion of the seat back  102  on the left side of the car body, so as to be connected to a pipe frame (not shown) on the left side of the car body. A mesh-like spring  117  having an end portion attached to the outside of the pipe frame  111  is set up in the rear of the shape-retaining material  116 . A pad  118  of sponge is attached into a portion surrounded by the front surface of the spring  117 , the rear surface of the shape-retaining material  116  and the side surface of the module-attachment bracket  112 . Another pad  119  of sponge is attached to the front surface of the shape-retaining material  116 . 
     A frontal center portion of the seat back  102  is covered with a first coating material  120 . Opposite, left and right side portions as well as an upper portion of the first coating material  120  are covered with a second coating material  121 . Further, opposite, left and right side surfaces, as well as an upper portion of the seat back  102  connected to the second coating material  121 , are covered with a third coating material  122 . Further, a rear surface of the seat back  102  is covered with a fourth coating material  123 . The first coating material  120  and the second coating material  121  are sewn together in a seam portion  124 . The second coating material  121  and the third coating material  122  are sewn together in a seam portion  125 . In the seam portion  125 , a ball edge  126  is sewn integrally. 
     On the other hand, a clip  128  is provided at an end of a tongue piece  127  extending from the seam portion  124 . The clip  128  is hooked on a spring  117  thereby keeping both the first coating material  120  and the second coating material  121  in predetermined shapes. Further, another clip  130  is provided at an end of a tongue piece  129  extending from the seam portion at the rear end of the third coating material  122 . The clip  130  is hooked on the retainer  113  thereby fixing the third coating material  122 . 
     The structure of the module M will be further described with reference to FIGS. 12 through 14. As shown in FIGS. 13 and 14, a holder  131  of a metal has a body portion  131 A substantially J-shaped in a cross-sectional view, and a pair of clamp portions  131 B,  131 B extending from one side edge of the body portion  131 A. A substantially cylindrical inflator  132 , filled with a propellant (not shown), is supported in a circular sectional portion which is formed by the body portion  131 A and the pair of clamp portions  131 B,  131 B. Both the holder  131  and the inflator  132  are enclosed in a rear end portion of the folded air bag  106 . The pair of bolts  114 ,  114  are fastened with nuts  134 ,  134  through the clamp portions  131 B,  131 B, the body portion  131 A and a side plate  133  and further fastened with nuts  115 ,  115  through the module-attachment bracket  112 . 
     The holder  131 , the side plate  133 , the inflator  132  and the folded air bag  106  are received in the inside of a module casing  135 , integrally formed from a synthetic resin. The module casing  135  has a tray-like body portion  135 A which opens to the right side of the car body, and a cover portion  135 C connected to a rear edge of the body portion  135 A through a hinge portion  135 B. When five stoppage teeth  135 D,  135 D . . . provided in upper, front and lower edges of the body portion  135 A are fitted into five stoppage cavities  135 E,  135 E . . . provided in upper, front and lower edges of the cover portion  135 C respectively, the cover portion  135 C is fixed so as to cover an opening of the body portion  135 A. Incidentally, the reference numeral  140  designates a harness cover for protecting a harness which is not shown but connected to the inflator  132 . 
     The shape of the air bag  106  in the air bag apparatus according to the present invention will be described below. 
     As shown in FIG. 15, the air bag  106  is constituted by a base end portion  106 A and a protective portion  106 B. Describing the shape of the air bag  106 , curved sides  106   b ,  106   b  extend from end portions, respectively, of a linear base end side  106   a  in the base end portion  106 A so as to be curved upward. The air bag  106  is set up so that the base end side  106   a  is located along a longitudinal direction of the module M. The curved sides  106   b ,  106   b  have substantially the same shapes. Each of the curved sides  106   b ,  106   b  is formed so as to extend slightly upward, extend further upward and finally face substantially the horizontal direction. Further, forward extended sides  106   c ,  106   c  extend substantially horizontally from the curved sides  106   b ,  106   b  respectively. Further, bent sides  106   d ,  106   d  extend from the forward extended sides  106   c ,  106   c  respectively. The bent sides  106   d ,  106   d  are bent in the directions to approach each other downward and upward respectively. The bent sides  106   d ,  106   d  are connected to each other by a vertical side  106   e . The air bag  106  has these sides so that the base end portion  106 A is constituted by a portion surrounded by the base end side  106   a  and the curved sides  106   b ,  106   b , whereas the protective portion  106 B is constituted by a portion surrounded by the forward extended sides  106   c ,  106   c , the bent sides  106   d ,  106   d  and the vertical side  106   e.    
     The air bag  106  is received in the seat back  102  so that the vertical side  106   e  turns to a substantially vertical direction when the air bag  106 , received in the seat back  102 , is inflated. In this condition, the forward extended sides  106   c ,  106   c  turn to substantially horizontal directions. 
     The air bag  106  having the aforementioned shape is received in the seat back  102 . FIG. 16 shows a state in which the air bag  106  is inflated. 
     As shown in FIG. 16, the module M is disposed in a comparatively lower position along the direction of the height of the seat back  102 . The base end portion  106 A of the air bag  106  is inflated to an direction Q higher than a direction P perpendicular to the longitudinal direction of the module M. 
     Assuming now that the chest, or the like, of an occupant is to be protected by the air bag  106 ′ inflated as a whole to a direction perpendicular to the longitudinal direction of the module M, then the module M must be received in an upper position of the seat back  102 , as represented by the dashed line in FIG.  16 . If the module M is disposed in an upper position of the seat back  102  as described above, the hardness of the module casing  135  containing the module M is transmitted to the occupant&#39;s back or shoulder thereby spoiling the occupant&#39;s comfort when riding because there is a little (thin) pad in the upper position of the seat back  102 . 
     On the contrary, when the air bag  106  is formed so as to be inflated to an upward direction Q directing more upward than a direction P perpendicular to the longitudinal direction of the module M, as shown in the air bag  106  in the air bag apparatus according to the present invention, the air bag  106  can reach the occupant&#39;s chest, or the like, thereby protecting the occupant&#39;s chest and head securely even in the case where the module M is received in a lower position of the seat back  102 . Accordingly, the module M can be disposed in a sufficiently thick lower position of the seat back  102 . Accordingly, there is no fear that the hardness of the module casing  135  containing the module M is transmitted to the occupant&#39;s back or shoulder so that the occupant&#39;s comfort when riding is spoiled. 
     Further, while the base end portion  106 A of the air bag  106  is inflated upward, the protective portion  106 B of the air bag  106  is inflated forward. Thus, the occupant can be protected by the protective portion  106 B securely. 
     A procedure of folding the air bag  106  will be described below with reference to FIGS. 17 and 18. 
     As shown in FIG. 14, the air bag  106 , before folding, is shaped like a flat bag made from two pieces of base cloth  136  and  137  sewn together in an outer circumferential seam portion  138 . The air bag  106  is fixed so that the holder  131  and the inflator  132  are enclosed in base portions  136 A and  137 A (rear end portions) of the two pieces of base cloth  136  and  137 . More specifically with reference to FIG. 14, the base portions  136 A and  137 A of the two pieces of base cloth  136  and  137  are fastened and fixed by bolts  114 ,  114  passing through both the body portion  131 A of the holder  131  and the side plate  133 , while the base portions  136 A and  137 A are sandwiched between the body portion  131 A of the holder  131  and the side plate  133 . The base portion  136 A of the base cloth  136  on the laterally outer side of the car body extends forward to a point a while enclosing the outer circumference of the inflator  132  at about 360° and then a foldable portion  136 B on the front side of the base cloth  136  is folded from the point a. On the other hand, the base portion  137 A of the base cloth  137  on the laterally inner side of the car body extends backward around a point b at the front end of the body portion  131 A of the holder  131 . After the base portion  137 A is then turned forward at a point c in front of the inflator  132 , a foldable portion  137 B on the front side of the base cloth  137  is folded from the point c. 
     In the air bag  106  inflated as shown in FIG. 15, the foldable portions  136 B and  137 B are folded from the front side to the rear side in the form of bellows as shown in FIGS.  17 ( a ) and  18 ( a ). Succeedingly, the air bag  106  is folded to a state shown in FIGS.  17 ( b ) and  18 ( b ). Then, as shown in FIG.  17 ( c ), upper and lower portions of the folded air bag  106  are folded downward and upward respectively so that the vertical height of the air bag  106  is reduced. Further, as shown in FIG.  18 ( c ), laterally opposite half portions of the folded air bag  106  are squashed so as to fall forward so that the lateral width of the air bag  106  is reduced. 
     Further, as shown in FIG. 19, opposite ends of a protective cover  139 , which is made from a piece of cloth to cover the folded air bag  106 , are fixed while being sandwiched between the body portion  131 A of the holder  131  and the side plate  133 . The air bag  106  which has been already folded, is packed in the protective cover  139  compactly so as not to come apart from the inflator  132 , the holder  131  and the side cover  133 . Incidentally, the protective cover  139  never disturbs inflating of the air bag  106  because the protective cover  139  is ruptured easily when the air bag  106  is inflated. 
     The operation of this embodiment having the aforementioned configuration will be described below. 
     When the inflator  132  generates a gas in a vehicle collision, the air bag  106  is inflated in the inside of the module casing  135 . When an inflating pressure of the air bag  6  acts on the cover portion  135 C of the module casing  135 , the stoppage teeth  135 D,  135 D . . . are disengaged from the stoppage cavities  135 E,  135 E . . . . As a result, the cover portion  135 C rotates around the hinge portion  135 B (see the chain line in FIG.  14 ), so that the body portion  135 A is opened. Further, when pressure for opening the cover portion  135 C shown in FIG. 12 is transmitted to the third coating material  122  of the seat back  102 , the seam portion  125  is ruptured so that the second coating material  121  and the third coating material  122  are separated from each other. As a result, the air bag  106 , passed through a gap between the second coating material  121  and the third coating material  122 , is inflated obliquely forward in a plan view so as to be along both the center pillar  104  and the front door  105  as shown in FIG.  11 . 
     Incidentally, when the air bag  106  begins to be inflated, the air bag  106  is inflated not just forward but laterally outward (in the inflating direction shown in FIG.  14 ), that is, obliquely forward in a plan view toward the center pillar  104  and the front door  105 . By inflating the air bag  106  in the aforementioned direction, both opening of the modular casing  135  and rupturing of the seam portion  125  can be performed accurately so that the air bag  106  is inflated correctly between the occupant and the combination of the center pillar  104  and the front door  105 . 
     Therefore, as shown in FIG. 14, a portion of from the point c to the point b in the base portion  137 A of the base cloth  137  on the laterally inner side of the air bag  106  is provided as a surplus portion b˜c, so that the surplus portion b˜c, is disposed so as to be along the right surface of the body portion  131 A of the holder  131 . Accordingly, when the air bag  106  is inflated, the surplus portion b˜c of the base cloth  137  on the laterally inner side rotates counterclockwise around the point b. As a result, the air bag  106  can move rightward (laterally outward) freely. Accordingly, the air bag  106  can be inflated obliquely rightward smoothly without interference with the occupant&#39;s right side and right arm. 
     FIG. 20 is a view showing the inflation of the air bag  106 . As shown in FIG. 14, the air bag  106  is folded so that a gas passage R is formed in the center. Accordingly, the gas generated by the inflator  132  directly strikes the seam portion  138  in the air bag  106 . As a result, the air bag  106  begins to be inflated vertically and forward as shown in FIG.  20 A. 
     The air bag  106  is further inflated gradually intactly as shown in FIG.  20 B. As a result, the air bag  106  is inflated perfectly as shown in FIG.  20 C. The perfectly inflated air bag  6  can protect the occupant&#39;s chest, or the like, securely because it extends forward. 
     While there has been described in connection with the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is aimed, therefore, to cover in the appended claim all such changes and modifications as fall within the true spirit and scope of the invention. 
     As described above, according to the present invention, inflating of an air bag can be performed quickly and securely, so that an occupant can be protected appropriately when a car is subjected to a side collision. 
     In addition, as described above, according to the present invention, a comparatively high position, such as the chest level, of an occupant can be protected securely, even in the case where a module is received in a low position of a side portion of a seat back so that occupant&#39;s comfort is not spoiled.