the invention provides a cutting assembly for cutting a moving strip of thin flexible material across its width , avoiding the possibility that the flexibility of the material will permit it to move away from the knife edge and not be cut , or be cut unevenly . the assembly comprises a knife - supporting member which is engaged with the moving strip and displaces it out of its usual path close to a roll in the path , so that a very short length of the strip is between two contacting members in the path adjacent to the knife . the knife is provided along its length with a plurality of distributed strip - engaging points pointing in the direction opposite to its direction of movement , which are moved into engagement with this short supported length of the strip , so that the strip movement drives it onto the points , and thereafter continues the movement of the strip into positive engagement with the succeeding knife edges . the assembly is particularly suited for the handling of flattened tubes of plastic material as produced by a blown film plastics line , wherein the continuous strip must be cut for subsequent handling and / or storage .