The roller (9.1-9.6) from which the strip is unrolled is rotatably mounted on at least one shaft (6) in a housing (1). The roller is braked by a brake arrangement (13). The housing has a base plate (2) from which the side walls (3,4) protrude at right angles. The shaft between the side walls is detachably inserted by means of fixtures (7,8) into guide gaps (5) in the side walls. A blade (12) fits by means of fixtures (14,15) between the side walls and has at least one slit (11) in it.
