A dual-roller conveyor belt comprising: a top side and an opposite bottom side , with a plurality of cavities extending from the top side to the bottom side ; an array of roller sets including: a top roller at the top side for supporting conveyed articles; a bottom roller at the bottom side in contact with the top roller such that rotation of the bottom roller in a first direction causes rotation of the top roller in an opposite second direction; wherein each top roller and bottom roller are arranged in a vertical stack in one of the cavities ; characterised in that the conveyor belt comprises channels along which the roller sets are translated from a first position in which the top roller extends to a maximum level above the top side and a second position in which the top roller extends to a minimum level below the maximum level ; and in that the conveyor belt further comprises a braking surface lying below the top roller so that the weight of a conveyed article resting on the top roller pushes the top roller against the braking surface . a top side and an opposite bottom side , with a plurality of cavities extending from the top side to the bottom side ; an array of roller sets including: a top roller at the top side for supporting conveyed articles; a bottom roller at the bottom side in contact with the top roller such that rotation of the bottom roller in a first direction causes rotation of the top roller in an opposite second direction; wherein each top roller and bottom roller are arranged in a vertical stack in one of the cavities ; characterised in that the conveyor belt comprises channels along which the roller sets are translated from a first position in which the top roller extends to a maximum level above the top side and a second position in which the top roller extends to a minimum level below the maximum level ; and in that the conveyor belt further comprises a braking surface lying below the top roller so that the weight of a conveyed article resting on the top roller pushes the top roller against the braking surface . a top roller at the top side for supporting conveyed articles; a bottom roller at the bottom side in contact with the top roller such that rotation of the bottom roller in a first direction causes rotation of the top roller in an opposite second direction; wherein each top roller and bottom roller are arranged in a vertical stack in one of the cavities ; characterised in that the conveyor belt comprises channels along which the roller sets are translated from a first position in which the top roller extends to a maximum level above the top side and a second position in which the top roller extends to a minimum level below the maximum level ; and in that the conveyor belt further comprises a braking surface lying below the top roller so that the weight of a conveyed article resting on the top roller pushes the top roller against the braking surface . the conveyor belt comprises channels along which the roller sets are translated from a first position in which the top roller extends to a maximum level above the top side and a second position in which the top roller extends to a minimum level below the maximum level ; and in that the conveyor belt further comprises a braking surface lying below the top roller so that the weight of a conveyed article resting on the top roller pushes the top roller against the braking surface . <EOS>