Multistage rolling mill and method of changing divided backing bearing assembled shafts in multistage rolling mill

A method of changing divided backing bearing assembled shafts in a cluster type multistage rolling mill that rolls a metal strip,

• the multistage rolling mill including a pair of work rolls rolling the metal strip, an intermediate roll group supporting the work rolls, a plurality of divided backing bearing assembled shafts supporting the intermediate roll group, the plurality of divided backing bearing assembled shafts each including a divided backing bearing, a shaft, and a saddle, a housing supporting the saddles, sliding apparatuses arranged on at least a drive side of the divided backing bearing assembled shafts, the sliding apparatuses including wheels, arms on the drive side and a work side of the divided backing bearing assembled shafts that respectively connect the divided backing bearing assembled shafts to the wheels, and a changing carriage disposed on a work side of the housing, the changing carriage having rails capable of being loaded with the divided backing bearing assembled shafts, wherein the sliding apparatuses and arms are part of the divided backing bearing assembled shafts,
• the method comprising:
• moving each of the divided backing bearing assembled shafts with the wheels of the sliding apparatuses rolling on any one of a housing bore upper surface constituting the housing, spray frame upper surfaces, and the rails of the changing carriage within the housing, and extracting the divided backing bearing assembled shafts from within the housing and inserting the divided backing bearing assembled shafts into the housing by moving the divided backing bearing assembled shafts with the wheels of the sliding apparatuses rolling on the rails of the changing carriage outside the housing.