Abstract: A peripheral portion in a hub is hollow, flat and defined by a pair of spaced and parallel surfaces. An annular periphery in this portion holds a tape in a wound configuration. An additional portion integral with the inner periphery of the peripheral portion has undulations each disposed radially. The undulations extend progressively in an annular direction. Preferably the undulations are in the form of corrugations each having oppositely disposed segments. Preferably each corrugation segment has the same angle as the other segment in such corrugation, this angle preferably being approximately 47.degree. C. Preferably the additional portion has first and second surfaces shaped to define the corrugations. Preferably the first surface of the additional portion is alternately substantially flush with one flat surface of the peripheral portion and then is spaced outwardly in a first axial direction from the other flat surface of the peripheral portion.

Abstract: A peripheral portion in a hub is hollow, flat and defined by a pair of spaced and parallel surfaces. An annular periphery in this portion holds a tape in a wound configuration. An additional portion integral with the inner periphery of the peripheral portion has undulations each disposed radially. The undulations extend progressively in an annular direction. Preferably the undulations are in the form of corrugations each having oppositely disposed segments. Preferably each corrugation segment has the same angle as the other segment in such corrugation, this angle preferably being approximately 47.degree.. Preferably the additional portion has first and second surfaces shaped to define the corrugations. Preferably the first surface of the additional portion is alternately substantially flush with one flat surface of the peripheral portion and then is spaced outwardly in a first axial direction from the other flat surface of the peripheral portion.