Forestry Application

Posted on Tuesday, October 18, 2016 in Case Studies

Southstar Tree Processor Comes Full Circle With UEA’s 360° Hydraulic Swivel

By: Daniel Hanawalt, Business Development Manager, UEA

This article originally appeared in Hydraulics & Pneumatics magazine.

When Southstar Equipment devised a full-rotation multi-tree processor, they needed to set the new logging attachment apart from the others on the market. A 360-degree rotating head and the ability to accurately process multiple trees at once helped Southstar do just that.

Previous models of Southstar processors had a 340-degree rotational limitation. To implement the crucial 360-degree rotating head, Southstar partnered with United Equipment Accessories (UEA) on a slip ring, hydraulic swivel combination assembly.Forestry Processor

“Together, the combination assembly allows both electric and hydraulic power to flow without interruption throughout the full 360-degree rotation,” said Dean Flaig, Technical Sales Manager at UEA.

The 20-degree variation between 340 degrees and a continuous 360 degrees makes a big difference. Because UEA’s combination assembly allows full rotation, Southstar’s customers see improved efficiencies, decreases in snags, and less maintenance. 

“Having the new 360-degree rotation standard in every machine is a huge selling point,” said Brad Matthews, partner and controller at Southstar Equipment. “Customers can do far more processing with the fully rotating head.”

Historically, Southstar had to purchase slip rings and hydraulic swivels separately—possibly from separate manufacturers. But UEA’s combination assembly allows one part to seamlessly integrate to support electro-hydraulic power flow.

“The expertise of UEA, combined with their eagerness to solve our problem, helped us in our fast-paced progress,” said Matthews. “UEA’s team came to the table for us as far as design and delivery.”

UEA lived up to its reputation by helping Southstar solve a challenging problem from the inside out.

Rotary Union and Slip Ring Combination“By designing these robust assemblies as a one-piece plug-and-play component—with integral electrical slip ring components incased inside of the steel housing of the hydraulic swivel—Southstar’s attachments are much more resistant to outside elements like weather, dirt and sawdust,” said Flaig, who alone has more than 20 years of experience working with hydraulic swivels.

Brady Haugo, UEA’s design engineer on the Southstar assembly, added, “We also used more difficult manufacturing methods to ensure the product was extremely robust. The main support flange could have been welded or bolted on, but for the sake of durability and robustness, we decided to machine it into the part even though doing so required a much bigger piece of stock material and more machining.”

The robustness is essential in harsh conditions. And harsh conditions are commonplace for Southstar processors. But wind, cold temperatures, debris, and other elements of tough logging environments don’t stop production.

Southstar’s customers also don’t have to stop production for tears in hydraulic hoses, which are virtually unheard of with UEA’s combination assembly.

“From the very onset of our meeting with Southstar’s engineering staff, we saw we were on a direct path toward solving a long-term drawback with their current design and the shortened life of the hydraulic hoses, said Flaig. “Unknown to us at the time, we also helped have positive impact on the operation and production cycle times to the processor head.”

With UEA’s combination assembly, Southstar’s new 360-degree attachments are now produced faster with a decreased assembly time.

Michael Klopp, VP at Southstar Equipment, said, “Now that we have gone to the combination-style assembly, we receive our swivel slip ring units pre-wired, which speeds up assembly time at the plant. We send these machines out and they work without any glitches right out of the gate.”

Thanks to innovation and quality, there are hundreds of Southstar’s multi-tree processors in the field, and demand continues to rise throughout North America and abroad.

About Southstar

Southstar Equipment is a world-leading forestry attachment manufacturer based in Kamloops, BC. Southstar designs and manufactures attachments that deliver efficient automated mechanized harvesting and processing for wood products. Learn more at

About UEA

United Equipment Accessories (UEA), based in Waverly, Iowa, designs and builds slip rings, hydraulic swivels, cable reels, and shift controls for OEMs throughout the world. Learn more at

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