Abstract: A tracklaying undercarriage for bulldozers, crawler loaders or other tracklaying vehicles including a central main frame and two tracklaying frames disposed on opposite sides of the main frame. The tracklaying frames are mounted at one end on mutually aligned supporting axles, which are fixed to the main frame, and at the other end on a rocker bridge, which is pivoted at its center to the main frame. The undercarriage also includes track chains, which are trained around driving and reversing chain sprockets mounted at mutually opposite ends of the tracklaying frames, and rotary hydraulic motors for driving the driving chain sprockets. The motors are supplied with fluid by hydraulic pumps, which are driven by an internal combustion engine mounted on the main frame. The tracklaying frames are mounted on the supporting axles by means of elastic bearings, which have outer and inner races that are interconnected by elastic material.

Abstract: Apparatus for tensioning a track chain of a tracklaying vehicle, such as a bulldozer, crawler loader or excavator, including a hydraulic cylinder for biasing a reversing chain sprocket which is rotatably mounted in a bearing that is displaceable in the vertical center plane of the track chain. The hydraulic cylinder communicates with a cylinder chamber that contains a floating piston provided with a check valve for connecting the two parts of the chamber which are disposed on opposite sides of the piston, and for preventing backflow from the hydraulic cylinder. The piston is displaceable in the cylinder chamber between forward and rear stops to an extent which corresponds to that volume of hydraulic liquid which is to be displaced in order to relax the previously tensioned chain to an optimum chain tension.