US Patent 9232851 Variable pitch mascara brush

A brush for applying mascara or the like, comprising an elongated core and a plurality of coating surfaces axially spaced along the elongated core, distributed around the core over a substantial portion of the length of the core extending from the distal end thereof. The coating surfaces are arranged in a plurality of rows forming turns of at least one helix extending lengthwise of the core and spaced laterally around the core periphery. The axial distance between consecutive rows of coating surfaces varies longitudinally along the core.