Abstract: An apparatus for sequentially forming a plurality of generally longitudinally extending grooves in the peripheral surface of a filter rod includes a hollow rotatable drum having a plurality of filter rod receiving channels formed in its outer peripheral surface for receiving filter rods to be grooved. The device includes filter rod indexing devices which engage the filter rods in the receiving channels. As the drum rotates about its central axis, the filter rod indexing devices are individually and selectively activated to incrementally rotate selected filter rods about their longitudinal axes through an angle corresponding to the angular spacing between adjacent grooves to be formed in the peripheral surface of the filter rod.

Abstract: A device for concurrently forming a plurality of generally longitudinally extending grooves in a filter rod includes at least one pair of groove forming rollers located in a common plane, with their axes of rotation generally parallel and with their peripheries spaced apart. A plurality of elongated, generally arcuately shaped groove forming projections are spaced apart from each other around the circumference of each of the rollers. Each groove forming projections of one roller is in opposed facing, coextensive, aligned relationship with a different one of the groove forming projections of the other roller across the space separating the peripheries of the rollers. As a filter rod to be grooved passes through the space between the peripheries of the rollers, the rollers are rotated and the groove forming projections embed into the peripheral surface of the filter rod thusly forming grooves into the peripheral filter rod surface.

Abstract: An apparatus for sequentially forming a plurality of generally longitudinally extending grooves in the peripheral surface of a filter rod includes a rotatable drum having a plurality of filter rod receiving channels formed in its outer peripheral surface for receiving filter rods to be grooved. The device includes filter rod indexing devices which engage the filter rods in the receiving channels. As the drum rotates about its central axis, the filter rod indexing devices are individually and selectively activated to incrementally rotate selected filter rods about their longitudinal axes through an angle corresponding to the angular spacing between adjacent grooves to be formed in the peripheral surface of the filter rod. A plurality of groove forming rollers are located at selected positions at the periphery of the drum. The rollers each have a plurality of groove forming blades projecting radially outwardly therefrom.