US Patent 7325889 Track having rotatable bushing and link for the same

In a track with a rotatable bushing which is brought into engagement with a sprocket of a track-type vehicle, it is intended that strength is enhanced rationally by link functionality sharing and by combination of such assigned functional tasks for achieving further improvements in rotatable bushing function. To this end, a track link comprises a combination of an external link and an internal link; a coupler pin hole is provided through the external link; a bushing hole is provided through the internal link, and the thickness dimension of a bushing hole formation part of the internal link is made greater than that of a coupler pin formation part of the external link.