Abstract: A rotary cutterbar includes a gear case containing a series-parallel set of gears including idler gears and pinion gears for driving the cutting discs of the cutter units. The gear case includes top and bottom walls and the idler gears are each received on a hub including an enlarged upper end located in a hole provided in the top wall and a threaded lower end screwed into a hole provided in the bottom wall. The hubs each have a plastic outer shell encasing a metal insert extending axially within the shell, with the shell forming the sole contact between each hub and the gear case whereby vibrations and shock loads respectively due to gear tooth contact and a cutter knife contacting an obstacle are absorbed by the shell to lessen the transmission of noise and the magnitude of the impact force. O-ring grooves are provided in the plastic shell and receive o-rings for preventing leakage from the gear case through the holes in the top and bottom walls.

Abstract: A rotary cutterbar includes a gear case containing a series-parallel set of gears including idler gears and pinion gears for driving the cutting discs of the cutter units. The gear case includes top and bottom walls and the idler gears are each received on a hub including an enlarged upper end located in a hole provided in the top wall and a threaded lower end screwed into a hole provided in the bottom wall. The hubs each have a plastic outer shell encasing a metal insert extending axially within the shell, with the shell forming the sole contact between each hub and the gear case whereby vibrations and shock loads respectively due to gear tooth contact and a cutter knife contacting an obstacle are absorbed by the shell to lessen the transmission of noise and the magnitude of the impact force. O-ring grooves are provided in the plastic shell and receive o-rings for preventing leakage from the gear case through the holes in the top and bottom walls.

Abstract: Provided are three joint assembly embodiments which each employ one or more threaded pivot pins for joining the leading ends of a first pair of track links with the trailing ends of a second pair of track links and for supporting a bushing adapted for engagement by a drive sprocket. In a first embodiment, the interior of the bushing and the leading ends of the second pair of links are threaded and receive a pair of threaded fasteners and the trailing ends of the first pair of links are pressed on the opposite ends of the bushing. A second embodiment differs from the first embodiment in that only one threaded fastener is used, the opposite ends of the exterior of the bushing are threaded and the trailing ends of the first pair of links are respectively threadedly received thereon. Also, a split wear bushing is removably received on the first-mentioned bushing.