SmithCo Mfg.
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SmithCo introduces patent-pending kingpin housing design

Nov. 15, 2024
The company’s updated kingpin housing is meant to increase its lifespan, with the company implementing the housing on all their over-the-road side dump trailers in late Q4 2024

SmithCo Mfg. has unveiled a patent-pending kingpin housing that provides longer life with fewer maintenance costs. The new housing will be included with all SmithCo over-the-road side dump trailers beginning in 2025.

Dump trailers are hard on kingpins, which connect a trailer to a fifth wheel and allows the trailer to pivot and maneuver behind the vehicle. As side dumps haul dirt, gravel, riprap, and more, they often are filled to max payload. Between the starts, stops, and dump cycles, the trailer’s kingpin sees a lot of stress over the course of months and years of use. For years customers have been forced to choose between removable kingpins that wear out, or weld-in kingpins that are harder to remove, costing owners extended downtime and increased shop costs.

SmithCo’s new solution combines the best of both worlds. The collet-style kingpin housing offers the security and durability of a weld-in kingpin without needing a plasma cutting torch to replace it. And the design locks the kingpin in solidly for a safe and reliable connection.

“We listened to our customers, and one thing they wanted was a longer-lasting kingpin and housing,” said Dan Dohman, SmithCo’s director of Engineering. “Our engineers developed a collect-chuck style kingpin housing that presses together and locks everything in place. This design secures the kingpin and eliminates movement without requiring the kingpin to be welded to the fifth-wheel plate. The results are a stronger, more durable connection that extends the life of the kingpin and reduces maintenance costs.”

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SmithCo worked with Iowa State University’s structures lab to perform accelerated life testing on the new kingpin assembly. Simulating 500,000 fully loaded start/stop cycles, they fatigue tested the new design, and after the half-million cycles, the kingpin showed no signs of movement within the housing.

Now, SmithCo is implementing the new design on all of their over-the-road side dump trailers. The kingpin housing will be part of trailers produced in late Q4 of this year, and SmithCo customers can expect the new design to arrive at dealerships in 2025.

“It is another great example of how we take customer feedback and engineer solutions to their problems,” said Dohman. “Customers will see extended service life and reduced downtime. We pride ourselves in being industry leaders, and this is just another example of how SmithCo is continuously striving to move the side dump trailer industry forward.”

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