Track link with driving lug releasably secured to track shoe

Claim 1

In an articulated endless track link assembly of the type used on a crawler tractor having a notched drive sprocket, each said link comprising: a pair of laterally spaced and vertically disposed side bars each presenting an upper rail portion, parallel pin and cylindrical bushing elements secured to and interconnecting corresponding opposite ends, respectively, of said side bars, a track shoe, connecting means releasably securing said shoe to the bottoms of said side bars, and a drive lug releasably secured to said shoe independently of said side bars and elements and disposed laterally between said side bars and intermediate the axes of said pin and bushing elements, said drive lug having front and rear convexly curved sprocket engaging surfaces facing in diverging directions and extending laterally substantially the full distance between said side bars, the top of said drive lug being of less height than said rail portions and lying substantially above the plane formed by said parallel axes, said sprocket engaging surfaces of said drive lug having centers of curvature on opposite remote sides, respectively, of the central transverse vertical plane through said lug and being more gradually curved than said bushing elements and having a size and disposition relAtive to said bushing elements to permit the drive lugs to be engaged by the sprocket notches prior to contact of said notches by either cylindrical bushing as each link enters the sprocket.