Jason Deters 2013-04-01 23:27:09
The Fredsert is a threaded insert patented by the General Dynamics Corporation in 2001. Engineer Fred Wheeler initially designed these inserts for the Expeditionary Fighting Vehicle (EFV). Wheeler designed the product to meet the unique demands of the EFV program, including: a watertight seal, solid locking to prevent back-out, corrosion resistance in extended saltwater exposure, and the ability to be easily removed and replaced in the field. The Fredsert has simplified vehicle design, improved producibility, and reduced program logistical costs. Today, there are nearly 4,000 Fredserts incorporated in each EFV, and the use of Fredserts has expanded to a number of other applications. The Fredsert geometry is effective in that it combines a tapered thread profile, full thread engagement, cutting flutes and a flanged head. These unique features deliver a combination of friction, fit, and material compression designed to resist vibration, tensile loading and shear loading in the Most demanding, heavy-duty applications.This new technology has fostered new attachment concepts, reducing the total number of fasteners, while at the same time introducing flexibility in vehicle assembly operations, reducing overall assembly costs.Also, logistical support costs have been reduced because removal and replacement of the inserts in the field is drastically simplified. The Fredsert is unique in that it doesn’t permanently lock into place. Instead, its patented geometry causes it to “break away” at approximately 80 percent of the installation torque value, allowing it to be quickly and easily removed and replaced using the same equipment. Field removal and replacement of commercially available inserts such as Keenserts and Rosans, on the other hand, increase logistical costs because the inserts must be drilled out because of their mechanical locking mechanisms. This becomes especially difficult if the insert is installed in a large structure or a tight enclo- sure, where access and rigidity are limited. Another feature that sets the Fredsert apart is its availability in titanium as a standard product, in addition to those made from stainless steel. This is a unique and important advantage, as titanium Fredserts deliver weight savings of 40 percent over Stainless steel inserts of the same size.Titanium inserts from other leading insert manufacturers, however, are either not an option or are quoted with an extremely high price and long lead time. A third key benefit differentiating Fredserts from the competition is that they create a 100 percent watertight seal without the use of a thread-locking agent such as Loctite. The combination of a tapered thread profile, 100 percent thread engage- ment, and a flanged head deliver a perfect seal on the OD thread of the insert. “Blind” Fredserts also deliver a watertight seal on the ID thread; the ID thread bore doesn’t break through the bottom of the insert. Fredserts provide tremendous benefit to General Dynamics Land Systems (GDLS) by providing unique design solutions, reducing installation costs, reducing vehicle weight, easing assembly operations, and reducing product logistical support costs. Efforts are underway to increase the marketability of the Fredsert product line in the commercial market, which will ultimately reduce costs to GDLS as Fredsert production quantities grow. ¦ JASON DETERS Jason Deters is a senior engineer in Process & Technology Development at General Dynamics. He has 14 years of experience in manufacturing, including Design for Manufacturing (DFM), pre-production planning, and production build activities. Deters is the Process Technology “Thrust Lead” for the General Dynamics Maneuver Collaboration Center (mc2), as well as a member of the Greater Detroit “Automation Alley” manufacturing advisory board. Deters is a certified Design for Six Sigma (DFSS) black belt and has involvement in improving manufacturing process flow, part producibility, throughput reduction, cost avoidance, and process robustness. Deters has an MBA from Walsh College of Business and Accountancy, a bachelor’s degree in organizational management, and technical degrees in mechanical engineering and mechanical design. In response to a changing global combat environment, today’s defense industry is transitioning in many cases to aluminum structures, leveraging weight savings that provide soldiers with agile vehicles with which to execute their missions. While aluminum provides substantial weight savings over steel, it’s also much softer than steel, leading to the use of stainless steel or titanium “threaded inserts.” Threaded inserts serve as a wear resistant interface between the aluminum structure and the hardened steel bolts used to attach components to the structure.
Published by American Fastener Journal. View All Articles.
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