CONTROL METHOD FOR WINDING MACHINE

PURPOSE:To prevent the generation of surface flaws of a strip by detecting a falling of a coil tightening force in the latter stage of the winding, then, reducing a pumping pressure below a set pressure based on a residual winding numbers. CONSTITUTION:For the coil 36 wound around a mandrel 12, a sensor consisting of a photocell 37 and light receiver 38 is disposed and the light receiver 38 is connected to a process computer 39, hydraulic circuit 40 successively. The hydraulic circuit 40 is formed by an enlarging circuit having passages 46, 49, a reducing circuit having passages 47, 49 and a pressure reducing circuit 50 having a decompression valve 52, relief valve 64, etc. When tightening force of the strip is reduced in the later winding stage, the sensor reduces the hydraulic pressure through a change-over valve 60 and relief valve 64 corresponding to residual winding numbers to reduce the expanding force of the mandrel. By this method, because the rapid expansion of the coil is prevented, the generation of the surface flaws on the strip is prevented.