Track chain joint with radial seal unit

An endless track chain device, comprising:

• first and second links, and
• a track chain joint comprising:
• a bushing to which the first link is fixed,
• a pin received in the bushing and to which the second link is fixed such that the pin and the bushing are rotatable relative to one another for corresponding relative rotation between the first and second links,
• an annular spacer spacing the bushing and the second link axially apart from one another, and
• an annular radial seal unit that inhibits ingress of debris between an end face of the bushing and the second link into a region between the pin and the bushing, the radial seal unit spaced axially apart from the end face and acting radially inwardly sealingly against the spacer therearound and radially outwardly sealingly against the second link, wherein the radial seal unit comprises an annular first radial seal and an annular second radial seal, the spacer comprises a first spacer step and a second spacer step radially inward from the first spacer step, the first radial seal sealingly contacts the first spacer step, and the second radial seal sealingly contacts the second spacer step and is positioned in a recess defined radially and axially between the first and second spacer steps.

An endless track chain device, comprising:

• first and second links, and
• a track chain joint comprising:
• a bushing to which the first link is fixed,
• a pin received in the bushing and to which the second link is fixed such that the pin and the bushing are rotatable relative to one another for corresponding relative rotation between the first and second links,
• an annular spacer spacing the bushing and the second link axially apart from one another, and
• an annular radial seal unit that inhibits ingress of debris between an end face of the bushing and the second link into a region between the pin and the bushing, the radial seal unit spaced axially apart from the end face and acting radially inwardly sealingly against the spacer and radially outwardly sealingly against the second link to establish a sealed radial connection therebetween and acting radially inwardly sealingly against the spacer and radially outwardly sealingly against the bushing to establish a sealed radial connection therebetween, wherein the radial seal unit comprises an annular first radial seal and an annular second radial seal, the first radial seal contacts the spacer and the second link, the second radial seal contacts the spacer and the bushing, the second radial seal contacts a radially inwardly-facing surface of the bushing and is positioned in axial spaced-apart relation from an axially-facing surface of the bushing, recessed axially only one step from the end face, in a cavity defined in the bushing between the axially-facing surface and the radially inwardly-facing surface.