Variable length shaft assembly

DETAILED DESCRIPTION This invention is a new and improved variable length shaft assembly for a motor vehicle steering system including a first shaft with a polygonal solid end telescopically disposed in a correspondingly polygonal end of a second shaft and with an arched spring disposed in a cavity in the solid end having a flat side bearing against a planar wall of the tubular end.
In a predetermined linear position of the tubular end relative to the solid end, an orifice in the tubular end registers with a slot in the flat side of the arched spring and cooperates therewith in defining a passage through which plastic is in situ injection molded into the cavity in the solid end behind the arched spring.
When solidified, the in-situ injection molded plastic defines a monolithic block around the arched spring having physical characteristics including high Young's Modulus, to capture the substantially zero linear clearance relationship between the tubular and solid ends for effectively lash-free torque transfer therebetween, and low coefficient of friction, for minimizing resistance to relative telescopic movement during multiple extend/retract cycles of the shaft assembly.
The flat side of the arched spring is exposed on the side of the monolithic plastic block facing the planar wall of the tubular shaft end and defines a wear plate on the plastic block for maximizing durability.