It is well known in motor vehicles to provide an air bag module mounted to a vehicle steering wheel. A typical driver's side air bag module includes a generally circular inflator positioned partially within a bag opening of an air bag for discharging inflator gas to inflate the air bag upon sensing certain predetermined vehicle conditions. The inflator, cover, and air bag are each mounted to the base plate to form the air bag module.
The cover of the air bag module overlies the air bag, inflator and other module components to form an aesthetically pleasing cover which is durable for normal vehicle use. The cover commonly has tear lines or weakened portions that allow the cover to open during air bag inflation. It is known to connect the cover of the air bag module to the base plate of a driver's side module or the housing of a passenger's side module by a plurality of fasteners. The use of multiple fasteners increases assembly time.
The prior art has also suggested the use of mating overlapping tabs on the cover and base plate or housing. However, assembly is still difficult since the tabs on the plate or housing are rigid metal which must be bent into place. The suggestion has also been made to form tabs in the cover which are trapped between the base plate and an additional relatively heavy plate-like structure needed to hold the cover in place during air bag inflation.
Many of the prior art covers have the significant disadvantage of being difficult to disassemble from the module, thus limiting access beneath the cover for serviceability of components, such as a horn switch. In addition, the module cover and fasteners in the prior art are likely to be damaged during disassembly of the cover from the module.