The invention relates to a device assembly for wrapping a heat sealing plastic film (3) coiled from a store roll (2) in a packing machine around goods (5) at a packing station (4), the device assembly comprising means movable towards the packing station to carry out the following periodical actions on the plastic film (3) coiled from the store roll (2)pressing it against the surface of the goods (5) at the packing station (4)heatingcutting andretaining the cut off end.The device assembly comprises a cylinder (1) having a length that is greater than the width of the plastic film (3) and movable towards the packing station (4) and away from it, at least two of the following being provided on its circumferential surface: a heating, retaining and a cutting zone. The retaining zone comprises in the longitudinal direction of the cylinder (1) at least one longitudinal slot or several consecutive inlets (6) connected with an aspirating canal (7) in the cylinder, and the cutting zone comprises a slot (9) having a length at least equal to the width of the plastic film (3) and extending into the hollow inside (8) of the cylinder (1) intended for a cutter (11) moveable back and forth in the slot (9) of the actuating device (10) inside the cylinder and emerging from the slot as it moves.