Patent ID: 7850256

Claim:
An endless track chain for use with a track-type vehicle, the endless track chain comprising: a first link set and a second link set, the first link set comprising a first link and a second link, the second link set comprising a third link and a fourth link, and a cartridge for relative rotation between the first link set and the second link set, the cartridge comprising: a pin, an inner bushing journalled on the pin for relative rotation therebetween, an outer bushing journalled on the inner bushing for relative rotation therebetween, an annular first spacer and an annular second spacer, the first and second spacers positioned axially outboard of the outer bushing, fixed to the inner bushing, and fixed respectively to the first and second links, a first collar and a second collar, the first and second collars positioned respectively axially outboard of the first and second spacers, fixed to the pin, and fixed respectively to the third and fourth links, an annular first seal and an annular second seal, the first and second seals captured between the outer bushing and the first and second spacers, and an annular third seal and an annular fourth seal, the third and fourth seals captured respectively between the first and second spacers and the first and second collars, wherein the inner bushing comprises a radial first bushing shoulder axially inboard of a first end of the inner bushing and a radial second bushing shoulder axially inboard of a second end of the inner bushing, the first spacer comprises a radial first spacer shoulder engaging the first bushing shoulder, and the second spacer comprises a radial second spacer shoulder engaging the second bushing shoulder.