Fluid operated torque tool for and a method of tightening a nut on a plate on railroad crossings
View Patent ↗A fluid operated torque tool tightens a nut through a spring washer on a plate on a railroad crossing, and has a housing, two coaxial drives applying equal turning forces in opposite directions around an axis, with one of the two coaxial drives located around the other of the two coaxial drives, a first socket attached to the one coaxial drive and configured to fit on the rectangular plate, and a second socket attached to the other coaxial drive inside the first socket and configured to fit on the nut, with the washer being not engaged by the sockets, so as to tighten the nut and to tighten up the spring washer onto the plate while the first socket and the housing stand still.
1. A method for tightening a nut on a plate of a railroad crossing, comprising the steps of arranging a washer between the nut and the plate; engaging the plate with an inner surface of a first socket so that the first socket passes over the washer without engaging the washer; engaging the nut with an inner surface of a second socket so that the second socket extends inside the first socket coaxially with the latter without engaging the washer; applying a force by one drive to the first socket engaging the plate so that the first socket stands still and holds the washer; applying a force in an opposite direction by another drive to the second socket engaging the nut so that the second socket is turned and turns the nut, so as to tighten up the nut through the spring washer onto the plate, without engaging the washer by the first and second sockets.