Pretension loading method for power transmission chain and pretension loading apparatus

A pretension loading method for a power transmission chain, in which a chain with an endless loop shape including a plurality of laminated link plates bendably connected to each other by pin members is wound around a plurality of rollers and the chain is endlessly rotated while a load is loaded on the chain so as to load pretension on the chain, the method comprising:

• a first maintaining of the chain in a substantial tension state without a slack by controlling tension of at least one of the plurality of rollers while endlessly rotating the chain;
• a first measuring of a length of the chain in the tension state;
• plastically deforming the chain to a target length by controlling a displacement of the at least one of the rollers to a predetermined location;
• a second maintaining of the chain in an other substantial tension state without a slack, the other tension state comprising a tension less than a tension required to cause plastic deformation of the chain by controlling tension of the at least one of the rollers;
• and
• a second measuring of the length of the chain in the other tension state,
• wherein the plastically deforming the chain, the second maintaining and the second measuring are repeated until a difference between the target length and the length of the chain which is measured in the second measuring is less than a predetermined value.