Energy absorbing steering column

Claim 1

In an energy absorbing steering column including a lower tubular mast jacket having an upper end, an upper tubular mast jacket having a lower end overlapping said lower mast jacket upper end whereby an annulus is defined therebetween extending longitudinally from said lower mast jacket upper end to said upper mast jacket lower end, said upper mast jacket being telescopically collapsible relative to said lower mast jacket through a working stroke, and a plurality of primary roll deformers disposed in said annulus in interference fit between said upper and said lower mast jackets so that longitudinal collapse of said upper mast jacket relative to said lower mast jacket is accompanied by energy absorbing cold working of each of said upper and said lower mast jackets, and the improvement comprising: a tubular plastic sleeve around said lower mast jacket having a primary part in said annulus between said upper and said lower mast jackets and a first secondary part adjacent said primary part and outside said annulus, each of said primary roll deformers being loosely received in said sleeve primary part so that the relative positions of said primary roll deformers is maintained during relative telescopic collapse of said upper mast jacket, a first plurality of secondary roll deformers loosely received in said sleeve secondary part outside said annulus whereby the positions of said first plurality of secondary roll deformers relative to said primary roll deformers is maintained during relative telescopic collapse of said upper mast jacket so that said first plurality of secondary roll deformers enter said annulus the axial dimension of said annulus expands during relative telescopic collapse of said upper mast jacket, and a first strippable retainer engaging said first plurality of secondary roll deformers outside said annulus between said upper and said lower mast jackets to maintain said first plurality of secondary roll deformers on said sleeve first secondary part.