Hybrid inflator adapter and secondary retainer

An adapter and retainer secures a hybrid inflator within the reaction canister of a passenger-side airbag module. It attaches to, or is integral with, the end wall of the canister and includes a cup which receives the nozzle end of the inflator. Surrounding the cup is a gas-impermeable flange. The flange includes compressive force means for applying clamping force to the inflator parallel to its longitudinal axis while resisting pressure buildup from within the canister during inflator actuation.

TECHNICAL FIELD 
This invention relates to motor vehicle airbag modules. More specifically, 
it relates to the mounting of a hybrid inflator in the reaction canister 
of a passenger side airbag module. 
BACKGROUND ART 
A motor vehicle passenger side airbag module customarily comprises a 
trough-shaped reaction canister having spaced sidewalls, a floor, and a 
pair of end plates. An inflator is mounted in the bottom of the canister. 
The folded airbag is also housed within the canister above the inflator. A 
suitable cover which may form a portion of the dashboard is adjacent the 
open mouth of the canister and is designed to break open under the 
influence of the expanding airbag. 
Some such passenger side modules employ hybrid inflators. A typical hybrid 
inflator is a cylindrical pressure vessel approximately 2.4" in diameter 
having a length of 5-15". The gas discharge ports are located at one end 
of the inflator. Because the gas is discharged very rapidly and from only 
one end, the flow parallel to the axis of the inflator causes high 
reaction canister pressure at the end plates. This high pressure makes the 
inflator to canister mounting difficult. It typically requires a welding 
operation to minimize gas leakage and guarantee inflator retention. 
It is an object of the present invention to provide means for retaining a 
hybrid inflator within the reaction canister without the need for a 
welding operation. Other objects, features and advantages will become 
apparent from the following description and appended claims. 
DISCLOSURE OF INVENTION 
The invention comprises means for securing an inflator within a canister 
which includes a cup in circumferential press fit engagement with one end 
of the inflator and coaxial with its longitudinal axis. The cup includes a 
base which receives and holds the first end of the inflator. An annular 
mounting plate surrounds the cup and is integral with the end plate of the 
reaction canister. A flange surrounds the cup and extends from the cup to 
the mounting plate to provide a gas impervious connection therebetween. 
The flange includes at least one compressive force member which is 
resistant to gas pressure build-up within the canister. As a result, the 
inflator is compressively retained between the end plates of the canister 
and gas leakage from the canister is minimized.

BEST MODE FOR CARRYING OUT THE INVENTION 
FIGS. 1 and 2 illustrate a reaction canister 10 having the customary 
sidewalls 12, 14, floor 16, and end walls in the form of plates 18, 20. 
Hybrid inflator 21 is mounted within the reaction canister 10 with its gas 
discharge openings 22 located at one end of the canister. An optional 
mounting stud 24 secures the base of the inflator 21 to the endplate 20 by 
means of a nut 26. The adapter and retainer of this invention engages the 
end of an inflator nozzle 28 and will now be described in detail. 
The adapter/retainer 30 of this invention may be made of a material such as 
steel and comprises a cup 32 which is coaxial with the longitudinal axis 
34 of the inflator 21 and is in circumferential press-fit engagement with 
the nozzle 28 end of the inflator. An annular base 36 extends inwardly 
from the wall of the cup 32 and engages the end face of the nozzle 28. An 
annular mounting plate 38 surrounds the cup 32 and includes mounting holes 
40 by which it is secured to the end plate 18 by means of screws 42, only 
one of which is illustrated. In this fashion, the mounting plate 38 is 
made integral with the end plate 18 and, in fact, it may form a portion of 
the end plate itself. Extending between the cup 32 and the mounting plate 
38 is a gas impervious flange 44. The flange 44 is characterized by a 
plurality of circumferentially spaced radial raised stiffening ribs 46 
which function as compressive force members resistant to gas pressure 
buildup within the canister 10. The dimensions of the adapter/retainer 30 
are such that, when the mounting plate 38 is snugly secured to the end 
plate 18, a substantial compressive force is applied by its base 36 to the 
end face of the nozzle 28 of the inflator. This serves to prevent any 
rattling of the inflator within the canister and also supplies a 
compressive counterforce against gas pressure buildup thus preventing 
leakage during inflator activation. 
FIGS. 3-5 illustrate an aluminum alternative to the steel construction just 
described. It is the functional equivalent and includes corresponding 
parts. Thus, it includes a cup 48 for engaging the nozzle 28 end of the 
inflator and a base 50 which abuts against the end face of the inflator 
nozzle. An annular mounting plate 52 is provided with lobes 54 containing 
mounting holes 56 by which the unit is secured to the end plate of a 
reaction canister by means of screws or bolts. A flange 58 provides a gas 
impervious connection between the cup 48 and the mounting plate 52. The 
compressive force member takes the form of a single thickened ring 60. As 
a result of the identity of elements between the FIG. 1 and FIG. 3 
versions, the functions of the two modifications are virtually identical. 
It is believed that the many advantages of this invention will now be 
apparent to those skilled in the art. It will also be apparent that a 
number of variations and modifications may be made therein without 
departing from its spirit and scope. Accordingly, the foregoing 
description is to be construed as illustrative only, rather than limiting. 
This invention is limited only by the scope of the following claims.