US Patent 10107325 Multifunction reaction washer and stack accessed by slim reaction socket

Accurate reaction socket access within an outer washer diameter is provided via a number of tool access castles extending from a stepped bushing and serration top, which in turn provides low friction during initial tightening and securing after final loading of a nut/bolt. Bottom serration slipping during initial tightening and thread locking during initial loosening are eliminated by the reaction washer stacked on top and in contact with a support washer via helical ramps and ramp mates. During initial tightening or loosening, the ramp mates slide up or down the helical ramps whereby an axial load on the nut/bolt is ramped up or down prior to screwing it on the main thread. A clamp ring or ramp indenters may secure the two washers. An interposition washer may extend the axial reaction range of the washer stack. Direct tension indicators may be combined with the ramp indenters.