Apparatus for cutting metal sheet

An apparatus for cutting a metal sheet, the apparatus comprising:

• (a) a pair of hollow shafts having respective axes extending in spaced parallel relation to each other, the hollow shafts being supported for angular movement about their respective axes, the hollow shafts having respective hollow bores whose respective axes are eccentric to the axes of the respective hollow shafts;
• (b) a pair of holder shafts fitted in the hollow bores of the respective hollow shafts for rotation relative thereto, the holder shafts having respective one ends projecting from the hollow shafts;
• (c) drive means associated with the other ends of the respective holder shafts for rotating the holder shafts about their respective axes;
• (d) a pair of circular cutting blades mounted on said one ends of the respective holder shafts in concentric relation thereto for rotation therewith, the cutter blades being adaptable for cooperating with each other to cut a metal sheet caused to pass therebetween;
• (e) interlocking means for angularly moving the hollow shafts about their respective axes in an interlocking fashion so as to move the respective axes of the holder shafts toward and away from each other to adjust an amount of gap between the cutting blades;
• and
• (f) a pair of fasteners mounted respectively to said one ends of the respective holder shafts, the forward end of each of the holder shafts being formed with a reference surface extending perpendicularly to the axis of the holder shaft, each of the fasteners having a plurality of urging means arranged along a circle concentric to the axis of a corresponding one of the holder shafts, the plurality of urging means urging one end face of the cutter blade mounted on the holder shaft to bring the other end face of the cutter blade into close contact with the holder reference surface of the holder shaft and thereby fixedly mount the cutter blade to the holder shaft, one of the fasteners including a cylindrical base in which a plurality of circular bores are formed in one end face thereof in circumferentially and equidistantly spaced relation to each other, a plurality of plungers being slidably fitted respectively in the circular bores, a plurality of coil springs being interposed under compression respectively between base end faces of the respective plungers and bottom surfaces of the respective circular bores, the plungers being biased outwardly from said circular bores under biasing forces of the respective springs so that as the one fastener threadedly engages with the forward end of the respective holder shaft, the plurality of plungers urge one end face of a fixing ring at a plurality of locations simultaneously to fix the respective cutting blade vertically in such a manner that the other end face of the respective cutting blade is brought into close contact with the reference surface of the respective holder shaft.