Steering column covering shell structure

A steering column covering shell structure for a steerable vehicle having a body structure, a steering column secured to the body structure and axially collapsible when subjected to axial load, and an instrument panel secured to the body structure, said shell structure comprising two shell members consisting of lower and upper shell members which are disconnectably held together to form therebetween a hollow space for allowing said steering column to axially extend in part therethrough, the upper shell member having an upward protrusion spaced apart rearwardly from said instrument panel, one of said shell members having a stress raising wall portion bounded by a continuous groove formed in one of said shell members, said stress raising wall portion being formed with an aperture located inside said groove and a plurality of radial slots radially extending outwardly from said aperture, and angularly spaced apart from each other about said aperture, said steering column having mounted thereon an electric switch assembly including a casing secured to the steering column and enclosed within said upper and lower shell members, said raised wall portion being secured to the steering column by means of a rigid fastening element passed through said aperture and clamped to said stress raising wall portion and said casing.