Abstract: An apparatus and method for customizing the pressure within an inflatable cushion of an air bag module is provided. The method comprises determining whether additional venting of an air bag is required. A sensing and diagnostic module will receive its relative inputs from a plurality of sensors and will determine whether vents in an inflatable cushion should be opened to allow diffusion of an inflation gas. The apparatus allowing vents to open at specified times to allow for diffusion of the inflation gas.

Abstract: An air bag module, having a housing with at least one vent opening; an inflatable cushion being stored in an un-deployed position in the housing; an inflator for inflating the inflatable cushion, the inflator being in fluid communication with the inflatable cushion; a deployable member being configured to cover the at least one vent opening; a tether element being secured to the inflatable cushion at one end and the deployable member at the other; an actuator adapted to restrain or release the tether element wherein the deployable member is pulled away from the at least one vent opening when the actuator releases the tether, the at least one vent opening is in fluid communication with the inflatable cushion when the deployable member is pulled away.

Abstract: An occupant restraint system includes an airbag having at least one vent hole and an inflator. The airbag is inflated by a gas generated by the inflator when there is a vehicle collision, and deploys into a curtain shape along an inner side face of an occupant compartment. Since the vent holes, through which gas is discharged from an inflatable part of the airbag, are made to open downward at the lower edge of the airbag, not only is it possible to reliably prevent the inflatable part from being excessively inflated, and thereby from becoming hard resulting in a failure to gently restrain an occupant, but also it is possible to prevent the vent holes from being blocked by the vehicle body or an occupant, thus reliably exhibiting a gas discharge function and preventing the gas discharged though the vent holes from directly impinging on the occupant.

Abstract: An air bag safety system for cushioning restraint of a vehicle occupant during an impact event. The safety system includes a variable depth inflatable air bag cushion inflated by a gas emitting inflator within an inflator housing. A cover element of substantially pliable material is located in adjustable relation to a vent opening across a wall of the housing. The cover element is selectively displaceable relative to the vent opening in response to the inflation depth of the air bag cushion so as to adjust venting characteristics across the housing.

Abstract: An air bag pressure control system for use in a vehicle is provided. The system comprises a housing, an inflatable cushion, and a dual stage inflator. The inflator generates a quantity of inflation gas to deploy the inflatable cushion from the housing. A vent opening is formed in the housing to selectively direct a portion of the inflation gas towards or away from the inflatable cushion. A sensing and diagnostic module detects an activation event level. A control algorithm tailors an inflation level of the inflatable cushion during deployment according to the activation event level.

Abstract: A vehicle occupant airbag deployment system (50) that detects, identifies and tracks a person (16) in the passenger seat (18) of a vehicle (12), and provides a signal for no fire, soft fire or hard fire of the airbag (20) depending on the location of the person (16) in a crash event. The airbag deployment system (50) employs infrared emitters (30) that emit an infrared signal towards the passenger seat (18) of the vehicle (12) and an infrared detector (34) that receive reflected radiation from objects in the seat (18). Processing circuitry (52), including face recognition software, is employed to detect human face features to provide the necessary detection and tracking of the person (16).

Abstract: Discharge valve for an airbag including a fixed member adapted to be arranged in connection with or associated with the airbag and having a pattern of openings and a movable member having a pattern of openings substantially identical to the pattern of openings of the fixed member. The movable member is movable relative to and alongside the fixed member to vary the correspondence between the openings on the movable member and the openings in the fixed member to thereby vary valve openings defined by the fixed member and the movable member. Variation in the valve openings results in control and/or regulation of the outflow of gas from the airbag through the discharge valve. The members may be plates, cylinders or cones.

Abstract: An apparatus (10) includes an inflatable device (12) for helping to protect a vehicle occupant, and an inflator (14) with inflation fluid outlets (24). A vent member (30) connected with the inflator (14) has a vent wall (60) having at least one vent opening (62). A vent cover (100) includes an outer wall (110) having first and second end portions (112 and 114). The vent cover (100) has a closed condition clamped on the vent wall (60) and covering the vent opening (62), and an open condition enabling fluid flow through the vent opening. An actuatable device (130) has an unactuated condition connecting the first and second end portions (112 and 114) to maintain the vent cover in the closed condition, and an actuated condition releasing the end portions to release the vent cover to the open condition to vent inflation fluid from the apparatus (10).

Abstract: An airbag is provided which securely prevents gas leakage through seams between panels and has excellent productivity. The airbag 10 has panels 1, 2. Peripheral portions of the panels 1, 2 are bonded with silicone adhesive 5 and also sewn together by sewing yarns 6A, 6B. Seams of the sewing yarns 6A, 6B may be coated by silicone sealant. The sewing yarn 6A composing an inner seam is thinner than the sewing yarn 6B composing an outer seam so that the sewing yarn 6A is broken during the inflation of the airbag 10, thereby absorbing energy.

Abstract: An airbag module for restraining an occupant of a vehicle, comprising: a housing; an inflatable cushion being capable of being stored in an un-deployed position in the housing, the inflatable cushion having at least one vent opening disposed on an inboard side and an outboard side of the inflatable cushion, the outboard side being positioned closer to an exterior portion of the vehicle than the inboard side; an inflator for inflating the inflatable cushion, the inflator being in fluid communication with the inflatable cushion; and a biasing device being configured to restrict the deployment of the inflatable cushion in a first direction while allowing for deployment of the inflatable cushion in an inboard direction and an outboard direction, the outboard direction being towards an exterior portion of the vehicle and the inboard direction being opposite to the outboard direction, the biasing device restricts the deployment of the inflatable cushion when a portion of the biasing device makes contact with the oc

Abstract: A vehicle occupant position sensor is mounted on the front of an airbag which is deployed toward a vehicle occupant. The sensor comprises a capacitance sensor constructed by rendering portions of the airbag which face the vehicle occupant conductive. The airbag on which the sensor is placed is also constructed to allow venting of the airbag before it is fully deployed. The distance between the sensor and the vehicle occupant is continually determined with respect to the sensor. The output of the capacitive sensor is processed by a control system and is used to predict the interaction between the airbag and the vehicle passenger and to cause the airbag to be vented if that interaction is predicted to be more harmful than beneficial to the vehicle occupant. A system which prevents airbag venting once the airbag is inflated or nearly inflated can also be employed.

Abstract: The overhead airbag system includes an inflatable cushion and a fill tube. The inflatable cushion has a first and a second opening. The fill tube has an outlet and two open ends. The fill tube passes through the first and second openings. The outlet is positioned within the inflatable cushion and the two open ends are positioned outside the inflatable cushion. An inflation source is in fluid communication with both the open ends of the fill tube. Upon deployment, the inflation source generates inflation gas that passes through the fill tube and into the inflatable cushion through the outlet. During inflation, the fill tube expands to limit passage of inflation gas between the fill tube and the perimeter of the first and second openings. Following inflation, the fill tube at least partially separates from the perimeter of the first and second openings to enable inflation gas to exit the cushion.

Abstract: A safety device for a motor vehicle has a gas generator, an airbag and at least one orifice through which gas flows. The state of fill of the airbag adjusts automatically to each load case by providing an orifice having a duct shape at least in a partial region. The flow resistance in this partial region adjusts automatically as a function of the velocity of the gas flow flowing through the orifice.

Abstract: An air bag module (100) comprising: a housing (20) including a receiving feature (20a) to receive at least a portion of an inflator (20), the inflator providing inflation gas to a cooperating air bag; this inflator being removably received in the receiving feature (20a); a holding member (40) movable between a first position and a second position, the holding member, while in the first position operatively holding an inflator (30) to a housing (20), the holding member movable between the first and the second positions under the influence of the inflator.

Abstract: Disclosed is an airbag for a vehicle capable of minimizing gas leakage in an early stage through gas discharge holes in a housing when spreading an air cushion. In both sides opposite to a first housing, the gas discharge holes are formed for emitting gas. A retainer on whose upper surface is fixed the air cushion, and in whose both sides are formed a coupling having coupling holes corresponding to the gas discharge holes, is provided. This coupling part is coupled to the first housing through the coupling device. The gas discharge holes are made lengthwise to make it possible to move the retainer up and down. As a result, when reading the air cushion, some of the holes are opened by movement of the coupling part. Besides, the coupling holes reformed in the lower side of the coupling part, so when not spreading the air cushion, the gas discharge holes are kept closed by the coupling part.

Abstract: An apparatus (10) includes an inflatable vehicle occupant protection device (14) and an inflation fluid source (32) actuatable to provide inflation fluid for inflating the inflatable vehicle occupant protection device. The inflatable vehicle occupant protection device (14) is inflatable to an inflated position for helping to protect an occupant (20) of a vehicle (12). The inflatable vehicle occupant protection device (14) includes at least one vent (60) positioned against a vehicle surface (62) while the protection device is in the inflated position to help block inflation fluid from venting through the vent.

Abstract: Apparatus (10) for helping to protect an occupant of a vehicle (12) that has a side structure (16) and a roof (18) includes an inflatable curtain (14). The inflatable curtain (14) is inflatable away from the roof (18) between the side structure (16) of the vehicle (12) and a vehicle occupant. The inflatable curtain has an inflatable volume (28). An inflation fluid source (30) is actuatable to provide inflation fluid to the inflatable volume (28) to inflate the inflatable curtain (14). A fill tube (32) delivers the inflation fluid from the inflation fluid source (30) to the inflatable curtain (14). The apparatus (10) includes actuatable means (60) for providing an opening (72, 226) in at least one of the fill tube (32) and the inflatable curtain (14) for directing the inflation fluid from the inflatable volume (28) to deflate the inflatable curtain (14). The actuatable means (60) is actuatable in response to actuation of the inflation fluid source (30).

Abstract: An air-bag is disclosed which has a vent hole formed therein. The periphery of the vent hole has first and second opposed part, wherein a tuck is formed in the air-bag. The tuck is formed in the region of the first part of the vent hole periphery such that the second part of the vent hole periphery extends past the first part in a direction extending substantially outwards from the interior volume of the air-bag, when the air-bag is inflated.

Abstract: An air bag safety system for cushioning restraint of a vehicle occupant during an impact event. The safety system includes a variable depth inflatable air bag cushion having at least one vent opening. A cover element of substantially pliable material is located in overlying relation to the vent opening. The cover element is selectively displaceable relative to the vent opening in response to the inflation depth of the air bag cushion so as to adjust venting characteristics.

Abstract: An airbag module comprises an airbag inflatable through an opening in the airbag. An airbag inflator provides an inflation gas into the opening in the airbag. A flap has a first position permitting gas to flow to the opening in the airbag and a second position deflecting inflation gas away fro the opening in the airbag. A propellant discharges into a discharge space moving the flap between the first position to the second position. A hood at least partially covers the discharge space.

Abstract: A safety device is disclosed which is configured to be actuated by the supply of gas. The safety device incorporates an outlet vent pipe which is sealed by a releasable clip. The releasable clip has a first elongate main gripping element and a second elongate moveable gripping element. The main gripping element has a retaining element to retain one end of the moveable gripping element. The safety device also includes an arrangement to retain the other end of the moveable gripping element in a predetermined position such that the clip may grip a fabric tube or the like between the main gripping element and the moveable gripping element. A mechanism is provided which responds to a supply signal to move the other end of the moveable gripping element to release the grip.

Abstract: A vehicle occupant protection apparatus (10c) has an inflatable occupant protection device (12c) and a support member (20c) having a vent opening (44c). A vent member (46c) is associated with the vent opening (44c). A tether (50c) extends between the protection device (12c) and the vent member (46c). The vent member (46c) is initially in a first condition closing the vent opening (44c). The vent member (46c) is moved to a second condition spaced apart from the vent opening (44c) and enabling fluid flow through the vent opening (44c) upon initial inflation of the protection device (12c). The vent member (46c) is moved from the second condition back toward the first condition by tension in the tether (50c) that results from inflation of the protection device (12c) away from the support member (20c) by more than a predetermined distance.

Abstract: An airbag arrangement including an airbag, a gas generator and a housing. The housing includes an outlet for letting gas out of the airbag arrangement and a passage for allowing gas from the gas generator into the housing. A closing device is provided. The closing device can be adjusted between an open position, in which the outlet is open and the passage is at least partially closed, and a closed position, in which the outlet opening is closed and the passage opening is open. A releasable lock is provided for locking the closing device in the open position.

Abstract: The invention relates to a gas bag module comprising a gas bag which has a gas bag wall with a front wall section. The module further comprises a cover which has a given annular section which closes an annular outlet opening for the gas bag and has a stationary central portion which is surrounded by the annular section. A section of the gas bag wall other than the front section has an outflow opening which in a folded state of the gas bag is arranged beneath the central portion in such a manner that on outlet of the gas bag, the central portion arrives via the outflow opening into an interior of the gas bag.

Abstract: An apparatus 10 for venting an inflatable restraint assembly 12. The apparatus 10 includes a conventional pyrotechnic cylinder 30 which is communicatively coupled to a controller 28, a selectively pivotable door 32 which selectively seals and/or covers an opening 33 within assembly 12, and a latch mechanism 34 which is coupled to the cylinder 30 and which selectively engages and disengages door 32. Controller 28 is communicatively coupled to a seat position sensor 36, seat belt sensor 38 and crash severity sensor(s) 40. Controller 28 determines when a crash situation has occurred or will imminently occur and selectively activates assembly 12 if such a determination is made, thereby protecting the vehicle occupant 18 from harm and/or injury. Controller 28 further determines whether and/or when to vent air bag module 12 based upon the data received from sensors 36-40 and selectively activates cylinder 30 in response to such a determination.

Abstract: A device for venting a gas bag made of a textile material includes at least one ignitable pyrotechnic charge which is associated with the gas bag in such a way that, when the pyrotechnic charge is ignited, at least one thread of the textile material is directly destroyed by the explosion of the pyrotechnic charge.

Abstract: An airbag module is provided. The module includes a housing, an inflator, an inflatable cushion, a vent aperture defined in the housing, and a gas deflecting member. The vent aperture places the interior of the housing in fluid communication with the exterior of the housing. The vent aperture is offset from exhaust ports of the inflator. The gas deflecting member is movable between a first position and a second position. In the first position, a first portion of the deflecting member deflects a first amount of the inflation gas to the exterior of the housing. In the second position, a second portion of the deflecting member deflects the inflation gas towards the inflatable cushion. A second amount of the inflation gas is ventable from the housing through the vent aperture when the deflecting member is in the second position.

Abstract: An air bag module for venting inflation gas if an out-of-position vehicle occupant is too close to the module for proper air bag deployment. The module has an air bag canister having a gas channel port, an inflator, an air bag cushion, a deployment door, a structural gas channel, and a venting system. The venting system connects the structural gas channel to the gas channel port and includes a plug and a plug pulling system for controlling the venting of gas.

Abstract: A vehicle occupant position sensor is mounted on the front of an airbag which is deployed toward a vehicle occupant. The sensor comprises a capacitance sensor constructed by rendering portions of the airbag which face the vehicle occupant conductive. The airbag on which the sensor is placed is also constructed to allow venting of the airbag before it is fully deployed. The distance between the sensor and the vehicle occupant is continually determined with respect to the sensor. The output of the capacitive sensor is processed by a control system and is used to predict the interaction between the airbag and the vehicle passenger and to cause the airbag to be vented if that interaction is predicted to be more harmful than beneficial to the vehicle occupant. A system which prevents airbag venting once the airbag is inflated or nearly inflated can also be employed.

Abstract: An airbag device includes an airbag that is deployed in front of a passenger's seat of a car, and an inflator for supplying gas to deploy the airbag. The airbag includes a lower bag segment for holding shoulders and a chest of an adult passenger when it is deployed, an upper bag segment that rises from the lower bag segment so as to hold a head of the adult passenger when it is deployed, and a partition cloth having an inner vent hole for separating the lower and upper bag segments. The inflator supplies the gas directly to the lower bag segment, and then to the upper bag segment through the inner vent hole.

Abstract: An airbag arrangement for a motor vehicle includes an airbag deployable in a direction to protect a vehicle occupant and an arrangement for limiting the unfolding impulse of the airbag upon an obstacle placed in a deployment path of the airbag to reduce the unfolding impulse transferred to the obstacle. The limitation arrangement, which can be, for example, a sheath, aperture in the airbag, can respond to the resistance of the occupant located in the deployment path, which is outside a normal seating position, or respond to a lack of resistance from the passenger. As the limitation arrangement limits the unfolding impulse of the airbag, it reduces the maximum unfolding impulse transferable to the occupant located outside the normal seating, in the deploying path.

Abstract: In an air-bag arrangement in a motor vehicle a gas generator (5) has a flange (8) which is spaced from a flange member (3) by elongate spacer elements (9). The spacer elements pass through apertures (20, 21) formed in an air-bag adjacent a central aperture (19). On inflation of the air-bag, the part of the air-bag surrounding the aperture will be drawn into an engagement with the flange (8). Should a very high pressure exist within the air-bag, the part of the air-bag surrounding the aperture will be driven away from the flange (8), with part of the aperture sliding along the elongate elements (9), thus permitting excess pressure to be relieved.

Abstract: An airbag module comprises an airbag inflatable through an opening in the airbag. An airbag inflator provides an inflation gas into the opening in the airbag. A flap has a first position permitting gas to flow to the opening in the airbag and a second position deflecting inflation gas away fro the opening in the airbag. A propellant discharges into a discharge space moving the flap between the first position to the second position. A hood at least partially covers the discharge space.

Abstract: An airbag module comprises an airbag inflatable through an opening and an airbag inflator in communication with the opening. A block selectively diverts inflation gas away from the airbag opening. The block may move from a first position and a second position, the first position permitting the inflation gas to flow to the opening and the second position deflecting the inflation gas away from the opening.

Abstract: A gas bag for a vehicle occupant restraint system has a covering forming a main chamber of the gas bag, with a passage opening, and an inner bag with an inflow opening and at least one ventilation opening. An edge of the inflow opening of the inner bag is connected with an edge of the passage opening and the gas bag has in a region of the connection of covering and inner bag a constriction for the inner bag. In a folded state of the gas bag, the inner bag is turned in into an interior of the covering and is able to emerge from the covering through the passage opening during an inflation of the gas bag.

Abstract: An inflatable vehicle occupant protection device (10) has a vent panel (40) defining a first vent opening (42) for enabling flow of inflation fluid out of the device. A vent strap (60) has a second vent opening (72) movable relative to the first vent opening (42). The vent strap (60) has opposite ends (62, 66) that are fixed when the protection device (10) is in the deflated condition. The vent strap (60) has slack (80) due to the length of the strap being greater than the distance between the locations where its opposite ends (62, 66) are fixed. One of the ends (66) of the vent strap (60) moves as the protection device (10) is inflated to remove the slack (80) and move the second vent opening (72) relative to the first vent opening (42).

Abstract: An airbag includes a fabric forming the airbag. The fabric has a vent hole for discharging some of gas introduced into the airbag to the outside. The vent hole is located at a position where the vent hole is not blocked when the airbag protects an occupant. This smoothly discharges gas, thereby improving the occupant protection performance.

Abstract: An airbag apparatus including a vent hole that is reliably opened the pressure of an airbag has reached a predetermined level. An apparatus includes inner and outer bags placed in a retainer in folded conditions and the retainer is closed by a module cover. The retainer has a vent hole. The vent hole is closed by a lid or sheet type closing structure. The module cover is pushed open by the inflation pressure of the inner bag. The gas in the inner bag is discharged into the outer bag to inflate the outer bag. When the inner pressure of the outer bag has reached a predetermined level, the closing structure opens to open the vent hole.

Abstract: The present invention provides an air bag apparatus in which an amount of a gas flowing into an air bag can be adjusted in a stepless manner.

Abstract: An air-bag is provided with a controllable vent, for example a tube, which is normally maintained in a closed condition by being retained by a clamp. The clamp is opened in response to a signal from a sensor. The clamp may be opened when it is desired for the air-bag to have a “soft” inflation, thus permitting a relatively high rate of flow of gas exiting from the air-bag.

Abstract: An airbag module capable of providing varying degrees of inflation to an airbag is disclosed. The airbag module has a housing with an interior and an exterior. A number of venting holes are located in the walls of the housing to allow gas to pass between the interior and exterior of the housing. These venting holes are sealed with a thin membrane to which an initiator is attached. The initiator is designed to create a hole in the membrane according to an input from sensors positioned within the automobile. Once the hole is created in the membrane, the gas pressure inside the housing forces the entire membrane to open and allows gas to flow out of the venting holes. The amount of gas emitted from the venting holes thus reduces the inflation of the airbag.

Abstract: An apparatus (10) for helping to protect an occupant of a vehicle includes an inflatable vehicle occupant protection device (12). An inflator (14) provides inflation fluid for inflating the protection device (12). A vent member (30) includes at least one vent opening (62) for venting the inflation fluid. A vent cover (100) has a closed condition for blocking fluid flow through the at least one vent opening (62) and an open condition for permitting fluid flow through the at least one vent opening. The vent cover (100) includes a side wall (110) that has at least one portion (134, 372) that projects from the side wall into the vent member (30) to help maintain the vent cover in the closed condition.

Abstract: A system for venting an air bag module having an air bag cushion retainer ring, an air bag cushion, an inflator, at least one spring positioned and compressed between the inflator and the air bag cushion retainer ring, a pyrotechnic rivet, sensors, and a restraint control module. If variable venting is required, the restraint control module signals the pyrotechnic rivet to release and the spring to urge one of the inflator or air bag cushion retainer ring away from the other of the inflator or air bag cushion retainer ring to create an opening between the retainer ring and the inflator to allow venting of the gas from inside the air bag cushion.

Abstract: A gas bag in which an orifice is opened or closed with the aid of a control band as soon as the gas bag has reached a predetermined state of deployment. One end of the control band is fastened to a gas bag envelope in the region of the orifice. The control band is connected at its other end to the gas bag envelope so that, when the predetermined state of deployment is reached, the control band slips into the gas bag envelope so that the orifice is closed by the slipped-in region of the gas bag envelope by the internal pressure of the gas bag, or the control band slips out of the gas bag envelope so that the previously closed orifice is opened.

Abstract: An algorithm for evaluating information from sensors interacting with strips that are extended during activation of the airbag determines whether the airbag has contacted an out-of-position occupant. In one embodiment, each strip includes an alternating pattern that generates a frequency in a sensor through which the strip passes during deployment. The frequency generated is based upon the speed with which the strip passes by the sensor and, in turn, the speed of deployment of the airbag. A controller evaluates the frequency and the changes in frequency from the sensor during deployment. Depending upon the specific configuration of the system and the specific vehicle, a decrease in the speed of deployment of the airbag may be indicated by a decrease in the frequency of the signal.

Abstract: A vent for an airbag is formed by at least two intersecting cuts disposed in the airbag material. Each cut terminates at opposite ends with a rounded end portion for stress release. The cuts are preferably placed in the cushion so as to be at 45 degree angles from the warp and weave threads of a woven cushion material.

Abstract: An airbag has a slit group arranged in a flexible peripheral wall. The slit group is formed by arranging a plurality of slits intermittently along one line. As an inflating gas flows into the airbag so that the internal pressure of the airbag rises, a portion designed to rupture between the slits ruptures to open a vent hole in the area of the slit group for discharging the inflating gas. At the peripheral edges of the individual slits of the peripheral wall, there are portions which are solidified after melting. In this airbag, the shape holdability is retained at the peripheral edges of the slits. Therefore, the effective area and the opening timing of the vent hole is uniform for every airbag.

Abstract: A fabric valve is disclosed that is made of a fabric blank folded in a pattern that promotes the flow of fluid in one direction along an axis of the fabric valve but restricts the flow in the opposite direction along the same axis. The fabric valve is easy to construct and is made by a series of folds. The fabric valve may be particularly suitable for use with inflatable safety devices used in vehicles, such as air bags and air curtains, to restrict backflow of gas from a given air bag when pressure, is applied to the bag. A method of making the fabric valve and a system incorporating the fabric valve are also disclosed.

Abstract: An apparatus and method for customizing the pressure within an inflatable cushion of an air bag module is provided. The method comprises determining whether additional venting of an air bag is required. A sensing and diagnostic module will receive its relative inputs from a plurality of sensors and will determine whether vents in an inflatable cushion should be opened to allow diffusion of an inflation gas. The apparatus allowing vents to open at specified times to allow for diffusion of the inflation gas.

Abstract: An occupant restraint system includes an airbag having at least one vent hole and an inflator. The airbag is inflated by a gas generated by the inflator when there is a vehicle collision, and deploys into a curtain shape along an inner side face of an occupant compartment. Since the vent holes, through which gas is discharged from an inflatable part of the airbag, are made to open downward at the lower edge of the airbag, not only is it possible to reliably prevent the inflatable part from being excessively inflated, and thereby from becoming hard resulting in a failure to gently restrain an occupant, but also it is possible to prevent the vent holes from being blocked by the vehicle body or an occupant, thus reliably exhibiting a gas discharge function and preventing the gas discharged though the vent holes from directly impinging on the occupant.