Abstract: Crawler tractor adapted for stepless hydromechanical steering by driving. The power train terminates in a novel hydromechanical steering differential delivering its output to an oppositely extending pair of axles at the sides of the tractor, and forced by a differential lock in a straight line locked, primary steering condition thereof to drive the axles at a mechanically fixed 1:1 drive ratio therebetween and, secondarily, forced into differentiating by a variable displacement crossfeeding pair of axle-interconnecting hydrostatic pump/motor units during all turns so as to selectively drive either axle only at some hydrostatically fixed reduction drive ratio to the other.

Abstract: Methods, apparatus, and improved structure having as their common basis the sequence of collapsing a piston ring in a fixture approximating engine bore diameter, and separately lapping a major portion of the ring side and a remaining locality --narrow in width, of band size and preferably line size-- of the side of the ring while it is so collapsed, until circumferentially continuous portions of the side are flat in the range of at least about 10 to five light bands. That is, out-of-flatness of the two circumferentially continuous portions, stated another way, is limited in each case to a range equivalent to about five to 10 light bands at maximum, at standard inspection wave length.

Abstract: Methods, apparatus, and improved structure having as their common basis the sequence of collapsing a piston ring in a fixture approximating engine bore diameter, and separately lapping a major portion of the ring side and a remaining locality -- narrow in width, of band size and preferably line size -- of the side of the ring while it is so collapsed, until circumferentially continuous portions of the side are flat in the range of at least about ten to five light bands. That is, out-of-flatness of the two circumferentially continuous potions, stated another way, is limited in each case to a range equivalent to about five to ten light bands at maximum, at standard inspection wave length.

Abstract: Arm stress equalizer in tiltable, diagonal strut braced, bulldozer blade mountings, comprising an intervening link having closely adjacent portions of the link proper universally connected to the inner end of different ones of the diagonal struts, and having a prolongation to the link proper rendering the latter swingable toward and from the bulldozer blade. The prolongation is disposed in the central longitudinal plane of the bulldozer, is at the lower end of the link proper, and provides an offset therein which extends diagonally downwardly and forwardly from the struts and the one end of the link proper. The geometry selected insures equalization of side-load-imposed stress in the so-called pusharms provided for mounting the blade, and further insures limitation of stress in the pusharms when, under the special circumstance of an imposed side load condition and a tilted blade condition, the tilt induced stress then tends to be additively superimposed in one of the already side-stressed pusharms.