Abstract: A steering shaft wherein energy absorbers are formed by filling a synthetic resin between the shaft and an outer sleeve. This steering shaft comprises a plastic metal pipe including, in a region remote from the steering wheel, a flat portion for connection to the outer sleeve, and a plurality of annular grooves to be filled with the synthetic resin. In a region adjacent the steering wheel, the plastic metal pipe includes an upper bearing mount, a screw for engaging a bearing retaining nut, a serrated shaft for engaging the steering wheel, and a screw for engaging a retainer nut, all defined as integral parts of the plastic metal pipe and arranged in the stated order toward an extreme end of the pipe. This steering shaft is lightweight, and may be manufactured in a reduced shaping time and at low cost.

Abstract: This invention relates to a shock absorbing type steering shaft for steering front wheels of a vehicle by converting rotation of a steering wheel to reciprocation of a tie rod, and to a method of manufacturing the steering shaft.The steering shaft has energy absorbers formed by filling a synthetic resin between the shaft and an outer sleeve. This steering shaft comprises a plastic metal pipe including, in a region remote from the steering wheel, a flat portion for connection to the outer sleeve, and a plurality of annular grooves to be filled with the synthetic resin. In a region adjacent the steering wheel, the plastic metal pipe includes an upper bearing mount, a screw for engaging a bearing retaining nut, a serrated shaft for engaging the steering wheel, and a screw for engaging a retainer nut, all defined as integral parts of the plastic metal pipe and arranged in the stated order toward an extreme end of the pipe.

Abstract: A transmission gear shifting lever of unibody construction from a hollow cylindrical material, comprising a connector part, a spherical part, a first cylindrical part, and a tubular lever body comprising a lower part, a tapered single cylindrical part, and a threaded part at the end, wherein the connecting part and the spherical part have wall thicknesses that are greater than the wall thickness of the first cylindrical part.

Abstract: The present invention relates to a method of manufacturing a power-transmission-gear-shifting lever which is made available for conventional passenger cars, trucks, agricultural machinery, civil-engineering and construction machinery, and other machinery by making up said lever with either a plastic or metallic tube, while the invention also relates to the constitution of the lever reflecting its preferred embodiments, wherein the manufacturing method is comprised of the sequential steps of first forming expanded tubular portion by expanding an end of tube with punching means, followed by contraction of the expanded tubular portion into eliptic shape using mold means before eventually cold-forging the eliptic portion into spherical shape, thus allowing the manufacturer to effectively save welding process and simplify assembly process before completing a light-weight gear-shifting lever.