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Automatic Bolt Feeding on a Multifunction Flextrack

Journal Article
ISSN: 1946-3855, e-ISSN: 1946-3901
Published October 18, 2011 by SAE International in United States
Automatic Bolt Feeding on a Multifunction Flextrack
Citation: Krejci, C. and Westley, J., "Automatic Bolt Feeding on a Multifunction Flextrack," SAE Int. J. Aerosp. 4(2):1429-1434, 2011,
Language: English


One of the largest advancements in the use of the Flextrack technology is the addition of automated fastener installation on the Multifunction Flextrack made by Electroimpact. The new Flextrack installs SSTF (Single Sided Temporary Fasteners) into the holes it drills without removing clamp-up force from the workpiece. This is the first Flextrack to drill and install fasteners and its functionality goes beyond even these functions. The fasteners, SSTF bolts, are increasingly replacing more cumbersome and manual tools for temporary fastening of aerospace components during assembly. They provide doweling, clamp-up, and feature a compact head to facilitate machine installation.
The new Multifunction Flextrack carries the bolts on the machine head as opposed to being fed through a feed tube. A Bolt Cartridge System carries up to 80 bolts onboard the Flextrack and the Cartridges can be quick changed for use with several different diameters. In its debut configuration, it is setup to carry 4 different bolt diameters, 1/4\mi through 7/16\mi in multiple grip lengths. The Flextrack Bolt Injector can receive a bolt from one of four banks in a fastener feed cartridge and presents it to the Bolt Inserter where length and diameter are checked. The Bolt Injector is mainly made up of a Cart that has multiple stop positions and transfers the bolt from the fastener bank to where the Inserter can pick it up. The Bolt Inserter resides on a shuttle table and the machine shuttles to the hole after drilling without losing clamp-up. The Inserter is driven to and from the panel with an air cylinder and installs the bolts with an electric nutrunner. To actuate the temporary fasteners, the nutrunner applies a torque to the inner hex drive while holding the outer head static. The bolts are actuated to specific torque values for different amounts of clamp-up force.