Abstract: In an oil seal for lubricated track chain joints, particularly for track-type vehicles, of the type with a flanged primary ring of a flexible material and a secondary ring of a resilient material, the annular portion (6) of the flanged primary ring (5) carries a metal ring (7) embedded in it.

Abstract: A safety device for a track stretcher of a tracked vehicle is disclosed. The safety device includes two half rings (14,15) held in a groove (16) of the tension rod (17) of the tracked vehicle by an elastic ring (20). The safety device prevents separation of the tension rod (17) from a support (2) connected to the roller wheel (1) upon failure of the primary thrust controlling stop device which includes a nut (22) screwed on the threaded end (21) of the tension rod (17).

Abstract: A two-piece master track link for connecting an endless track for heavy duty track vehicles, consists of two half-links each having a mating surface comprising of a recess and a hook-like projection, so that the hook-like projection of one link part is received in the recess of the other link part. The recesses and hook-like projections are so shaped that in assembling of the half links by screws or bolts all the mating surfaces adhere to one another and prestress the screws owing to the configuration of their profiles. Said profiles consist each of an oblique portion merging into a substantially horizontal portion merging in turn into a central portion inclined with respect to an imaginary vertical plane at the angle of friction of about 10.degree. and sized to have a ratio with respect to said oblique portion ranging between 1 to 4.