Down and Dirty: Oil-impregnated bearings
on the potato-planter pick arm suffered from wear and corrosion until
replaced with a plastic
The 24 pick arms around each large pick wheel on a Harriston Industries potato planter each pivot from 12 to 20 times a minute to plant seeds. But separate problems arose with the original arm bearings (oil-impreganted brass-bushings with graphite plugs), the nature of which differed depending on the region where the planters are used.
The high volcanic ash content in northwestern soils created abrasive wear and premature failure. In Maine and the Canadian Maritimes, salt in the air caused corrosion and bearing seize up. Service Department engineer Dave Paschke says the company replaced the arm bearing with an igus iglideŽ J series plastic bearing. This increased life on western machines five to six times and on the east coast eliminated seizing and corrosion. Another plus was a 70-80 percent cost reduction.
The iglide bearing is pressed into a brass sleeve to maintain dimensional stability. Next this sleeve is pressed into the pick-arm base. A 1034 stainless steel pivot pin, with a manite coating to provide R62 hardness, rotates within the plastic bearing through a 15-degree arc when the pick arm moves.
Contact: Tom Miller, igus inc.
Tel (800) 521-2747; Fax (401) 438-7270