Stevens Urethane Cord Adds Durability, Versatility
To Power Transmission Belts

Stretch belts for power transmission are often essential components in manufacturing and distribution. Because reliability is critical, the material from which these belts are fabricated must be strong and durable, as well as abrasion- and chemical-resistant.

Urethane combines the best properties of rubber and plastic in most environments. With both the elongation and recovery characteristics of rubber and the chemical resistance of plastic, urethane is ideal for stretch belt applications.

Thanks to a proprietary welding process, stretch belts for power transmission and conveying are now being manufactured by Dura-Belt, Inc., Hilliard, OH. The company fabricates the belts from extruded urethane cord supplied by Stevens Urethane.

The urethane cord is cut to length and welded into an O-ring, which is then twisted, leaving small loops at either end. These loops are joined by a connector, creating an O-ring of the twisted cord. This type of belt offers very fast changeover compared to a traditional endless O-ring. They are often used as replacements when conveyor belt drives or other power transmission belts break. Minimizing downtime is critical, and these belts provide quick fixes to keep the line up and running. They are also used full time, and for applications requiring interconnected O-rings looped through each other. The connectors on the TPU twisted belts make them easy to unfasten, loop through an endless O-ring, and then refasten.

“We needed a urethane from a domestic manufacturer that was strong and highly resistant to abrasives and chemicals.” says Jim Hammond, president of Dura-Belt. “Our urethane belts must have a very long flex-life, and a high coefficient of friction, which is important for gripping pulleys and rollers. We also needed the right material for each specific application -- materials which would perform well in temperatures ranging from 10°F to 150°F, or for short periods between -40°F up to 180°F.”

Dura-Belt’s proprietary welding process enables the firm to put urethane’s advantageous properties to good use in its products, providing superior durability in a broad range of applications, as proven in tests by a number of Dura-Belt customers.

Hammond prefers Stevens Urethane for its high quality, consistency, and value.

“Purity is one reason that I like the Stevens Urethane cord. It is made from 100% virgin polyurethane and it's a very uniform material. Their tolerances are very precise; it’s hard to beat their products,” says Hammond.

“Moreover, Stevens Urethane is a very clean product, which is important to us because some of our belts go into clean rooms, and into food processing applications which require top-grade materials,” explains Hammond.

“Of course cost is another factor,” says Hammond. “I prefer using urethane cord from a domestic manufacturer like Stevens, rather than having to buy a more expensive product from foreign suppliers.”

The impact of the high quality of the Stevens Urethane is felt throughout Dura-Belt’s manufacturing process.

“Because the product is so pure, we are able to make stronger welds,” he says. Dura-Belt also has a proprietary process for color-coding belts, and the pure Stevens Urethane cord is easier to color. “When compared to urethane cord from other domestic sources, the Stevens material is clearly superior,” says Hammond.

“We went through a series of five trials with other U.S. manufacturers, and nobody else was able to meet our specs, not only for tolerance, but for roundness as well,” Hammond says. “And Stevens has been great to work with, too. They provide good, prompt delivery, and in a rush, they've always been there for us.”