Combining Functions Saves Time, Costs Costs Improves Quality
This article originally appeared in Hydraulics & Pneumatics
Virtually all heavy equipment in construction, mining, agriculture, and similar off-highway applications relies heavily on hydraulics. And a good number of these machines use rotating members that require transmitting hydraulic fluid from a fixed location to components on a rotating assembly. Rotating joints (swivels) have served this requirement well by functioning as slip rings for hydraulics. But rotating swivels don't transmit electrical power or signals, so designers have to specifiy hydraulic swivels and electric slip rings separately. A simpler and more economical solution is offered by United Equipment Accessories (UEA), Waverly, Iowa
When slip rings and hydraulic swivels are specified separately, equipment is at higher risk for failure and requires added assembly and more maintenance, according to UEA's Dean Flaig. Using a combination unit - a slip ring and hydraulic swivel cohesively designed together as a single assembly- improves economies of scale and reduces the number of components, suppliers, and the potential for component failure.
"When slip rings and hydraulic swivels are supplied from one company, your design is cleaner and the parts are more resistant to outside elements like salt spray and adverse weather," added Flaig. With more than 20 years' experience working with hydraulic swivels, Flaig has seen firsthand the benefits of a combination unit. "It's the heart of the machine. Slip rings and hydraulic swivels are a natural match."
Purchasing slip rings and hydraulic swivels separately has its drawbacks. First, the chance of human error increases from having two suppliers. Second, the parts come separately instead of packaged as a single component, causing additional logistical coordination and scheduling. Third, the OEM has to align and bolt the two components together.
Conversely, tangible benefits exist for having the slip ring and hydraulic swivel engineered and built as a combination unit. First the component is ready to install on the machine, with no assembly required to combine two parts. Second, the swivel and slip ring are guaranteed to be compatible because they come from the same manufacturer. One design form one source drives down overall costs of complete assembly. Finally, purchasing and follow-up service all goes through one company instead of two. Flaig said, "With one supplier, the component expertise is all-inclusive. You go to one source with any questions, problems, or changes related to the swivel and slip ring."
Feedback from the Field
Michael Klopp, director at Southstar Equipment, Kamloops, B.C., Canada, has seen the benefits of using UEA as its single combination unit supplier, "In the past we used separate slip rings and we were constantly trying to match them to the swivel, which caused reliability issues and lack of confidence in the slip rings. Now that we've gone to the combination-style units, we receive our swivel/slip-ring units pre-wired, which also speeds up assembly time. We send these machines out, and they work without any glitches right out of the gate"
Other UEA companies are seeing reduced assembly time, higher quality , and better compatibility by purchasing combination slip ring-hydraulic swivel units. For Zach Dockter, engineering support manager at Manitex, the benefits are clear. He explained, "I choose to purchase combination hydraulic/electrical swivels because it reduces assembly time in our manufacturing plant. The fewer parts needed to assemble a machine typically means fewer chances for costly assembly errors,"