Winding shaft for sheet rewinder

A sheet winding shaft comprising:

• a hollow shaft having a plurality of through-holes formed in the peripheral wall thereof so as to be disposed radially at predetermined intervals, the wall surfaces of said hollow shaft defining each of said plurality of through-holes each of said plurality of through-holes having an inner projection provided at the inner end of each said through-hole;
• a plurality of retainer rings each provided in the outer open end of each said through-hole;
• a plurality of drum rings rotatably fitted about said hollow shaft to close the outer open end of each said through-hole and each having an inner periphery serving as a frictional suface;
• core-locking means each provided on the outer periphery of each said drum ring to come into contact with the inner periphery of a core;
• a plurality of pairs of support rings, each pair of which has outer peripheries fixed to the opposite ends of the inner periphery of each said drum ring rings and each pair having the inner peripheries thereof kept in contact with the outer periphery of said hollow shaft, thereby supporting each of said drum rings on said hollow shaft;
• a plurality of plungers each provided with a flange and each movably inserted into each said through-hole, each said plunger having a length large enough to project both outwardly from each of said retainer rings and inwardly from each said inner projections, each of said flanges having a diameter larger than the inner diameter of each said retainer ring and also larger than the inner diameter of the inner projections;
• and
• an expansible air tube provided in said hollow shaft and, when being expanded, adapted to outwardly urge said plungers within said through-holes.