Steerable axle assembly with preloaded kingpin drawkeys

In a steerable axle assembly including a transverse axle beam defining an elongated vertically oriented boss at one end, said boss defining a pair of vertically spaced ends and having a bore extending fully between said ends, said assembly further including a pivotal steering knuckle defining a bifurcated yoke having upper and lower arms, said arms including aligned apertures adapted to mate with opposed ends of said bore, said assembly further including a cylindrical kingpin supported within said bore and extending through said apertures, said boss comprising a cross aperture extending transversely to and partially intersecting said bore, a drawkey supported within said cross aperture, said drawkey including an elongated head having a tapered flat surface adapted to engage said kingpin, wherein said kingpin has a tapered flat surface for mating with said tapered flat surface on said head of said drawkey, said drawkey including a threaded shaft portion having an end extending externally of said cross aperture, said end having a nut threaded thereon for securement of said drawkey against said kingpin;

• an improvement comprising spring means interposed between said boss and said nut for preloading said drawkey against said kingpin and for providing a relatively constant force to avoid slack or clearance due to kingpin wear, wherein said spring means comprise two deflecting disc spring washers positioned about said threaded shaft portion of said drawkey, each washer defining inner and outer circumferential portions, said washers positioned so that in their uncompressed form, their inner portions are in contact with one another while their outer portions bear against said boss and said nut, respectively.