An annular locking device (15) for winding of reels is intended to be arranged alongside a plurality of same annular devices so as to realize a winding shaft. The device comprises an outer ring (16) and engagement elements (17) protruding from the radial surface of the outer ring. The outer ring being rotatable in the device between a first angular rest position and a second angular locking position, in the first angular rest position the engagement elements (17) being radially retracted or elastically retractable and in the second angular position the engagement elements (17) being elastically retractable less than in the first angular rest position. The device comprises the engagement elements (17) which are distributed along at least three circumferential lines of the radial surface of the outer ring (16). This ensures a high degree of flexibility as regards the widths of cores which can be handled by the device.
