“On January 4, 2007, Congress passed the Implementing Recommendations of the 9/11 Commission Act. Included in the bill’s provisions was a mandate that the Department of Homeland Security (DHS) scan 100 percent of maritime cargo entering the United States by 2012. Given the fact that approximately 11.6 million cargo containers enter U.S. ports each year, this mandate could cripple the ability of the private sector to move goods on time.” The mandate is to deploy a system that can rapidly scan containers without creating bottle necks. This system is now available.
One of the critical aspects of this new scanner design is the linear rail and roller block system that allows the 2000 pound detector to move vertically. LM76 was chosen to engineer this aspect of the new container system which is now being deployed at port terminals. Mike Quinn of LM76 had this to say about the challenges LM76 faced:
“There were several challenges we had to overcome – none more pressing than the ability to stand-up to the salt air/spray environment. We had to take a system that is not all-weather and make it all weather. Not easy when you have sealed rollers that are steel running on a steel shaft. We had to choose a system that would offer low friction, tolerate contamination and not rust away. Looking over all our products, we chose the OSG roller Block/Rail assembly as our base system: http://www.lm76.com/speed_rail_osg.htm
According to company President John Tarbell: “Each rail is 24 feet long and poses it’s own challenges. We did not want to butt joint rails because the mounting surface is less than flat. If we employed rails that required butt joining – due to the overall length of the rails – we could experience very rough transition points that could negatively affect the life of the bearing block rollers. The LM76 OSG system allows us to construct almost unlimited rail lengths.”
|Exploded View of OSG Rail
||Staggered Shafting for Smooth
Transitions Rail to Rail
|4 Roller Block Feature Open Design
As shown, the OSG rail is a two piece rail that allows you to stagger shafting from 1 section to another so you can avoid butt joining. This makes for very clean transitions from rail to rail.
Next, to protect the shaft from corrosion, LM76 used a special anti-corrosion treatment – Stay-Tough LM 12:
Resulting properties from these chemical and structural composition changes are increased surface hardness, lower coefficient of friction, enhanced surface lubricity, improved running wear performance, increased sliding wear resistance, and enhanced corrosion resistance.
Next, to protect the rollers from corrosion we chose an enhanced surface treatment that encapsulated the roller, pin and the sealed bearings inside.
The 2000 pound scanner package is raised and lowered via a steel cable. Thus, the OSG linear system does not experience the load directly. The OSG bearings act more as linear guidance for the scanner as it moves throughout its travel.
The original beta system has been in operation for over a year without issue.