At the San Antonio quarry of Redland Stone Products Inc., the steel-cable belting on long load-out and field conveyors often needed expensive repair or replacement because belts drifted into supporting steelwork. The Persuader return-belt conditioner from Flexco Inc. in Bell, Calif., has eliminated this problem by funneling the belt into a centered position rather than steering it there.

This conditioner minimizes drifting by pressing down on the return belt's bottom cover, thereby funneling the belt into a centered position

The drifting problem was especially insidious on the quarry's railroad load-out conveyor. This elevated conveyor has a 48-inch-wide belt spanning the 1,400 feet from blending piles to railhead. Running at 500 feet per minute with a maximum capacity of 2,200 tons per hour, this belt is the sole means of rushing custom-blended orders, usually in railcar-sized batches of 100 tons, to a pair of overhead silos straddling the tracks.

Control-room computers monitor zero-speed sensors, motor amperage, and other inputs to detect problems in belt movement. When a problem occurs, this system triggers an audible alarm and a visual alert on the control-room screen and logs the incident on a daily printout summary. Any incident that stops the belt shuts down upstream production. These safeguards, while helpful, were not enough to protect the belts completely from damage, and Redland still wanted to avoid the wear from frequent stopping and starting.

The Persuader design uses a pair of short rollers angle-mounted across the belt in fixed position, pressing downward against the return belt's bottom cover along the outer areas of belt width. These rollers funnel the belt into a centered position as it approaches the tail pulley so it will be in the correct position to receive its load. Because the Persuader has no pivots to wear out, seize, or require maintenance, its only moving parts are the rollers.

Each positioner installs as a single piece, using an adjustable-width mounting bracket that attaches to the conveyor framework with two bolts on each end. A sliding, bolt-tightened adjuster enables the user to determine the amount of roller pressure applied to the belt.

After the first installation ran about a month with no edge damage, Redland ordered 10 more positioners for its other field conveyors.

Mail at the Leeds facility is separated at sorting stations, then placed into three-sided trays that travel along the conveyor track. Thirty-seven trays—each holding 350 letters—circulate throughout the system. At presorting machines, the trays are manually lifted off the track, emptied, and replaced on the conveyor for a return trip to the sorting stations.

The circular track of the conveyor is composed of an XL chain with roller cleats. It is 110 yards long and rises in three places to about 23/4 yards, enabling personnel to pass under to different workstations easily. The conveyor tilts at a 60-degree angle for vertical transport so letters do not fall out.

The mail system is used about 20 hours per week during the facility's busiest period. Up to 75,000 letters pass through the facility daily.

These 52-inch-long grippers are elastomer-coated and operate at 11.5 pounds per square inch

Made of elastomer-coated fabric, the grippers are designed in a wide range of sizes and shapes for slip-resistant gripping, carrying, palletizing, and depalletizing. Consisting of inflatable tubes of cylindrical and bell-shaped cross sections, the grippers operate at 11.5 pounds per square inch. Bottles are gripped as two or more tubes, aligned side by side, inflate and envelop the upper portion of each bottle. Even slope-shouldered containers are held securely by the high-friction elastomer coating.

The large range of bottle sizes accommodated within each size of gripper—plus the quick changeover of gripper sizes and types—helps ease the problems associated with short-run and flexible manufacturing.

The servo-control system uses a number of dc motor assemblies specially developed to provide precise motion control within a demanding servo-loop environment. Each motor assembly provides a high degree of stability and accuracy, and has been designed to withstand the severe environments the vehicle will experience—dust, water spray, humidity, and temperature extremes as well as the shock of an explosion and the vibration of rugged terrains.

The motor assemblies' enhanced electromagnetic performance and reliability are provided via a high-energy rare-earth magnet system, which ensures consistently high torque at speeds up to 5,000 rpm. Velocity feedback is provided by the company's high-performance tachometer, which has robust thermal characteristics and linearity over a wide operating range.

The EV1 electric vehicle from General Motors is powered by a battery pack consisting of 26 12-volt lead-acid modules. MagneTek's CM2H001 motor drives a pump, which provides power steering for the vehicles. The pump is manufactured by Saginaw Steering Systems in Saginaw, Mich., a division of GM. A vehicle control senses the amount of steering required, and activates the electric motor and pump only when they are needed. By doing so, the power-assisted, variable-effort electrohydraulic steering system uses 65 percent less energy than the conventional hydraulic systems used in gasoline-powered cars.

The motor operates on voltages ranging from 20 to 180 volts and frequencies ranging from 20 to 90 hertz. The three-phase, four-pole motor is 4 inches in diameter and has a distributed wound frame. The motor is normally wound as a permanent split capacitor for typical air-moving applications.

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