US Patent 7043808 Tool for installing blind threaded fasteners

A tool for installing blind threaded inserts utilizes an expanding mandrel to engage the threads of the insert being installed. The expanding mandrel is an externally threaded assembly having a plurality of movable segments separated by axially-extending radial slots. The slot width is chosen such that when the mandrel is in a collapsed state the external diameter of the mandrel will pass through the minor diameter of the insert's internal thread. The segments are movable radially between a collapsed state, the condition of the mandrel segments when they are in their inward most position of minimum diameter, and an expanded state, when the mandrel segments are moved outwardly to their position of maximum diameter. The mandrel of the invention also extends and retracts axially to compress and thereby install the deformable insert.