This invention relates to occupant restraint systems and more particularly to occupant restraint systems of the type which releasably secure the cushion against initial deployment normal to or toward the occupant and direct such initial deployment laterally of the occupant
U.S. Pat. No. 5,009,452, Occupant Restraint System, issued Apr. 23, 1991 to Gregory A. Miller and assigned to the assignee of this invention, discloses an occupant restraint system which includes a reaction member mounted to the support of the restraint module and located above the inflator of an occupant restraint system. The reaction member is sealed to the upper wall portion of the occupant restraint cushion to prevent the impingement of pressure fluid from the inflator against such upper wall portion during initial deployment of the cushion and thereby restrict such initial deployment laterally of the occupant through the unfolding of the folded side and end walls of the cushion.
This invention provides an occupant restraint system having a reaction member of the type disclosed in the Miller patent and having additional features.
One of the features of the occupant restraint system of this invention is that the reaction member is mounted to the support by a flexible strap or mounting member having a bight which loops through a pair of spaced slots or openings located in the center area of the reaction member. The legs of the strap pass around the inflator and downwardly through the inflator receiving opening of the support to the underside thereof. The ends of the legs are doubled over and secured to the underside of the support. If, desired the legs need not be secured to the support since the doubled over ends prevent the ends of the legs from being pulled upwardly of the support between the inflator and the inflator receiving opening of the support. By mounting the reaction member to the support by a flexible strap, the size of the inflator module can be reduced since the folded end walls of the cushion can be moved inward toward the inflator and occupy the space otherwise occupied by the supports for the reaction member in the Miller patent. Additionally, the mounting member permits the reaction member to shift or move slightly relative to the support and inflator if required.
Another feature is that the reaction member is pocketed to the inside of the upper wall portion of the cushion to seal the interface between the reaction member and such upper wall portion of the cushion. In one embodiment of the invention, the pocketing includes flaps of flexible material, such as the same material as the cushion, which are sewn or otherwise secured to the inside of the upper wall portion of the cushion adjacent the periphery of the reaction member and overlap or overlie such periphery. The flaps are of truncated triangular shape to leave the center area of the reaction member uncovered and not interfere with the passage of the strap therethrough. The side edge portions of the flaps overlie or overlap each other. The flaps are releasably secured to the reaction member by a retainer member which sandwiches the flaps to the reaction member. The retainer member is centrally secured to the reaction member and releasably secures the flaps to the reaction member by shearable fasteners which extend through the overlapping side edge portions of the flaps. The retainer member is provided with slots or openings in general alignment with those of the reaction member so that the bight of the mounting member can extend therethrough. In another embodiment of the invention, the pocketing includes a sheet of flexible material of the same general shape as the reaction member but slightly larger. The edge portions of the sheet are sewn or otherwise secured to the inside of the upper wall portion of the cushion adjacent the periphery of the reaction member. The center area of the sheet of flexible material is open and slits, perforations, or other types of tear lines extend diagonally from such center opening toward the corner portions of the sheet of flexible material. The slits, perforations, or other types of tear lines terminate slightly short of the corner portions of the reaction member so that the sheet of flexible material pockets the reaction member to the upper wall portion of the cushion. This embodiment also includes a retainer member centrally secured to the reaction member and sandwiching the sheet of flexible material to the reaction member. However, there is no need for the retainer member to include any shearable fastening means for releasably securing the sheet of flexible material to the reaction member.
When the folded undeployed cushion initially receives pressure fluid from the inflator, the initial deployment of the cushion is laterally of the occupant as the folded side and end walls of the cushion unfold. The pocketing of the reaction member to the upper wall portion of the cushion by the flaps or sheet of flexible material seals the interface between the reaction member and such upper wall portion of the cushion and prevents the entry of the pressure fluid therebetween. Thus, the upper wall portion of the cushion remains generally stationary and does not move toward the occupant during initial deployment of the cushion. As the pressure fluid continues to fill the cushion, the side and end walls unfold into continuations of the pocketed and sealed upper wall portion. When the pressure and volume of the pressure fluid reach certain levels, the pocket is ruptured by (1) the flaps being pulled from between the retainer member and reaction member as the shearable fasteners shear, or (2) the sheet of flexible material tearing or rupturing along the tear lines into flaps connected at the corner portions of such sheet, to permit the flaps to move with the upper wall of the cushion toward the occupant. The flexible mounting member retains the reaction member and retainer member in place. Since the flaps are formed of flexible material, the occupant cannot feel or engage the flaps through the cushion should the occupant engage the outer side of the upper wall of the cushion.