Teflon bearings (PTFE) inside the aluminum cylinder that surrounds the hex-shaped steel shaft facilitate linear motion. And when the shaft rotates, it advances two clear, urethane transfer belts. |
Automated machines that are basically mini chemical labs are helping researchers map the human genome. Equipment from Vantage Automation Technology Inc., Libertyville, Ill., aids in the search by speeding the preparation of thousands of chemical samples for study. Lube-free bearings on the main drive shaft that moves samples helps head off contamination problems. The self-lubing bearings also meet outgassing limitations.
A 3 /8-in. hex shaft on the device has two nonmetallic hex bearings epoxied into a crowned aluminum drive tube. The bearings, from Duralong Bearing Div. of Rexnord, Downers Grove, Ill., have PTFE liners that let them slide along the stainless-steel hex shaft at up to 24 ips without lubrication. The shaft and bearings also rotate through 90° to move two transfer belts. The hex shape of the shaft lets it generate this rotational force without slipping while still allowing the necessary linear motion.
The bearings are comprised of a filament-wound fiberglass epoxy matrix with PTFE and polyester bearing elements. Using filament construction lets the bearings be manufactured inside the housing that accommodates the hex shaft. The self-lubing bearings also meet outgassing limitations.