Sounds like a long shot, but Winegard, a Burlington, Iowa, manufacturer and supplier of television antennas, did exactly that by using powder-metal (PM) parts for a new RV antenna.
The Winegard Trav’ler antenna lets RVs receive Dish Network or Direct TV signals while parked. When the unit powers on, it unfolds from a 10-in.-tall stowed position on the vehicle’s roof. The antenna automatically points at the appropriate geostationary satellite by adjusting rotation, elevation, and skew.
Winegard engineers reviewed various options for gears and bearings in its positioning assembly. Parts stamped from solid metal proved to be more expensive than powder-metal parts, and stamped parts also limit designers to off-the-shelf parts or face long lead times and hefty custom-design markups, says Winegard lead mechanical engineer Tim Conrad. “Going to PM on these was more cost effective than wrought metal gears,” he adds.
PM-part maker Symmco Inc., Sykesville, Pa., collaborated with Winegard to design components and tooling for both the skew and elevation mechanisms while keeping manufacturing efficiency in mind. For instance, the motor drive’s PM pinion and bevel gears to operate the skew mechanism, while the elevation assembly contains two bronze PM bearings impregnated with oil. Symmco also pressed stock bearings into a custom iron PM block to form a worm gear retainer.
Bud Jones, Symmco director of engineering, said the two-part design was both functional and cost saving. “Iron powder is about $0.80/lb while bronze is closer to $5/lb. The iron retaining plate provides good structural support and keeps costs down, while the self-lubricating bronze bearing lets the gear rotate freely.”
The Trav’ler antenna measures only 10 in. high when its packed for travel. But when the driver parks the RV and activates the antenna, it deploys and orients based on the satellite signal. The skew mechanism is directly behind the dish. The elevation assembly, including an oil-impregnated bronze PM bushing, is in the base.
A worm gear drives the Trav’ler’s elevation mechanism. An oil-impregnated powder-bronze bearing mounted in a powder-iron plate holds the gear in place. Iron construction provides strength and keeps raw material costs low while the bronze permits free rotation.
The Trav’ler antenna uses motor-driven pinion and bevel gears in its skew assembly. Both gears, shown disassembled, are formed from powder metal.
