Abstract: A track assembly hinge joint for a track of an endless track vehicle, in which track links are connected by a pin and bushing, is formed by securing the ends of the pin in bores in the ends of a pair of spaced link members and securing the bushing in the inner portions of bushing and pin accommodating bores in the ends of the adjoining pair of link members, with a self-lubricating bearing sleeve disposed between the bushing and the pin and with a self-lubricating washer disposed between each end of the bushing and a side thrust control ring on which a radially inner element of a two-element lip type seal is mounted for cooperation with an outer seal element which is seated in the outer end portion of the bore in the associated link member adjacent the end of the bushing.

Abstract: A two-element seal assembly for sealing relatively rotatable members wherein each seal element has annular radial lip type sealing contact with the other. The seal elements are shaped in a complementary fashion, one with relation to the other, whereby an annular labyrinth is formed therebetween and entrance of damaging materials into sealed area of an installation is effectively excluded by the lip seals and the labyrinth.

Abstract: A track idler recoil assembly is mounted on a crawler tractor for resiliently resisting longitudinal movement of a yoke-mounted track idler caused by track deflection. The assembly comprises a spring housing, open at one end and closed at the other, rigidly secured to the tractor track frame; a coiled compression type recoil spring within the spring housing; and means, including a pushrod and a hydraulic ram, to transmit force between the track idler yoke and the spring and to enable installation and removal of the spring in uncompressed condition. The pushrod is detachably connected to the idler yoke and extends through a hole in a rigid portion of the track frame. The hydraulic ram is located between the pushrod and the spring and is slideably supported in a tubular spring restraining member which is mounted on the spring housing and movable axially into the open end thereof to fixed position to hold the spring in a precompressed condition.