UEA Tech Talk

Slip Rings -Slew Indication Part 2

 ...Continued from Blog: Slip Rings -Slew Indication Part 1

 A variety of encoders have also been used with UEA slip ring assemblies over the years but relatively new on the scene are encoders with a CANopen or J1939 output.  These are most frequently used, at this point, on mobile or construction equipment with similar needs to those supplied by the potentiometers.  Because they operate on a CAN communications system the encoder can become just another sensor on the system and its position above or below the center of rotation is immaterial once attached to the CANbus circuits passing through the slip ring.   As more engine controls and remote sensors adopt the CANopen or J1939 output the use of this type of encoder will become even more popular.

As always, United Equipment Accessories, Inc. is available to answer any questions you may have about our products, or this blog post.  Please feel free to contact us at 1-877-352-4739 or email at info@uea-inc.com. We promise that you will speak directly to an employee in our office, never an answering service!  Check out www.uea-inc.com for more helpful information about United Equipment Accessories Inc, and our products.  Hope to hear from you soon!

-Brent, Senior Design Engineer

 

UEA expands! Slip Ring Assembly

The latest recession has been challenging for many businesses, including United Equipment Accessories, Inc.  However, because of our excellent staff we have managed this downturn far better than those of the past.  Not only have we shown our team how highly they are valued by retaining all full time staff, we have never stopped planning for the future and striving to put systems in place for better efficiency and capacity.

The end of 2009 saw our investment in two new CNC machining centers.  One is a horizontal and the other is a vertical style unit.  Both are state of the art units that will expand our production capacity and capability for continued market expansions. 

We are also planning a facility expansion that will be spread over two years.  The first expansion will be 4,300 square feet on our south plant facility this spring.  This will allow us to have separate areas for shipping and receiving to facilitate better material flow.  It will also allow us to move both our shift control and cable reel departments back into the south facility.  This expansion will connect to a present warehouse to facilitate inventory storage flowing to production.  With this expansion, our south facility will have no more room for contiguous growth.

2011 will see an expansion of our north plant facility with an additional 14,000 square feet.  Since our present CNC area is nearing maximum capacity, we need additional space for not only machine department area, but also potential assembly area. 

As you now realize we never stop thinking about the future.  We want to have the capacity to always meet our customer's needs.  We want to have to facilities to add people and equipment to produce the products on which our customer's rely. 

-Mark Hanawalt, President

UEA Slip rings: A Bridge Between Three Centuries

 As the many varied custom slip ring projects flow through the doors of United Equipment Accessories, occasionally one will seem to have a life and story of its own. Such was the case with the project involving the restoration and upgrade of the "Government Bridge" between Davenport, Iowa and the Rock Island Arsenal in Rock Island, Illinois.  This particular bridge sits atop the lock and dam #15, right between the gates.  It is what is commonly called a "swing bridge".  The bridge swings a full 360 degrees, allowing large boats and the tugs that push the numerous barges that travel up and down the Mississippi river channel to pass through.  The bridge structure carries auto and truck traffic on its lower level and two railroad lines on its upper level. The mechanism that allows this rotation is situated on the center pier between the locks, supporting the complete 366 ft section of the bridge on a series of rollers. Around the base of this structure a pair of very large roller chain "tracks" crawl their way around what looks like a giant sprocket which is part of the main base of the bridge. These tracks are driven through shafts, one on each side of the bridge, that extend up to the control house over 50 feet above. Inside the control house is a large electric motor and a series of gears to drive these shafts.

  This is the forth of a series of bridges at this location, which was the first railroad crossing the Mississippi river. The first bridge was built in 1856. It was burned two weeks after opening by the disgruntled river boat operators as they claimed it impeded navigation.  It is speculated that the competition that the railroad was going to present was a big part of the issue.  Abraham Lincoln defended the railroad in the court case that followed in 1857.  A second bridge was destroyed by a tornado in 1868. To see a more detailed history click here. Or go to http://www.riveraction.org/node/28.

  The present bridge was completed in 1896. Since that time, all the power for the motor as well as all controls and functions of the bridge was supplied by a wooden insulated slip ring that sat above the control house just below the high voltage lines that pass over the top of the entire bridge structure from shore to shore.  These power lines are supported on their own set of rollers that allow the bridge to rotate below them while still supporting them.  It was this space between these power line supports and the control house below that United Equipment Accessories was requested to create a custom slip ring to conduct the power and signals necessary for the day to day operation of this marvelous piece of engineering.  Due to the exterior nature of this location an enclosure for the slip ring would have to be completely weather proof for all of the extremes that this part of the country can deliver, from -30F to well over +120F when baked by the summer sun. Since United Equipment Accessories wanted to provide a solution that would last as long as the predecessor slip ring, with a minimum of maintenance, a stainless steel enclosure and supports was clearly called for. A special rope type seal was used on the 6" diameter main shaft coming in from above, as it would not be feasible to remove the enclosure or shaft for seal replacement.  This type of seal can be wound around the shaft for replacement when required.  It uses an adjustable gland to apply pressure, similar to the packing in a faucet stem.  Because of the number of circuits and the size of the cables a 6-8" bore range slip ring was required. This slip ring would be inverted in the enclosure, with the shaft coming in from the top and the core hanging down from it.  All circuits coming into the slip ring from the power lines above would pass through the inside of the shaft to the rings.  From there the brushes take the power from the slip ring and pass it to the cables that exit the bottom of the enclosure to the control house below.  Included in the slip ring with the power circuits are several communication circuits for all purposes from the railroad signals to telephones and video monitoring equipment which was added to the bridge during this major upgrade.  As part of the yearly winter shutdown the bridge goes through a full maintenance routine prior to reopening for the spring thaw.  United Equipment Accessories, as part of its dedication to customers, has agreed to provide an annual inspection during this shutdown to insure that this slip ring continues to provide the critical power and control needed to support the bustling river transportation industry.

Above: Arial view of the bridge in operation as a boat steams into the lock.

 Above: UEA Slip ring inside bridge