Conveyors that elevate and pile beets in 32-ft tall heaps during harvest now use drivetrains with self-aligning planet carriers that float radially and axially to automatically align and balance conveyor loads.
The conveyors mount on machines called pilers, which consist of a receiving hopper, conveyor belt, a screen to remove soil and other debris, and a boom. They were installed on a fleet of 106 pilers owned by the agricultural coop American Crystal Sugar Co., Moorhead, Minn. The fleet previously relied on drives from several suppliers, but this caused maintenance headaches, as well as problems when conveyor parts became obsolete. Reliability became an issue for the seasonal business.
To solve the problem, the company standardized its pilers and processing plants on one suite of gear drives from Rexnord Corp., Milwaukee.
In the conveyors’ planetary gear drives, Rex tapered roller bearings support overhung and thrust loads on both input and output shafts. Spline connections isolate the gear train from external forces. Taconite duty-rated seals and two seals on each shaft sport greasepurgeable cavities that keep out dirt and moisture. An internal backstop ensures safety for the incline conveyor. When required, the drive’s standard subassemblies allow fast gear ratio changes in the field without shimming bearing clearances, bearing adjustments, or even special tools.
Rexnord Quadrive shaft-mount reducers power the conveyors onto which farmers’ trucks dump beets. The conveyors’ hardened and surface-finished helical gearing is sized to handle large loads. Seals are grease-purged Viton that withstand high temperatures. A torque-assist taper bushing eliminates binding found with twin-taper and single-flanged bushings.
Falk Ultramite gearmotors drive the tracks that move the pilers, stacker boom swing, and hoist. The gearmotors’ generate low speed directly, which is important because previous multireducer drives were prone to ill-timed failures. Gearbox bearings, not motor bearings, support a built-in high-speed pinion. The gearbox accepts standard NEMA C-face motors, so they are easy to remove and replace.