Abstract: This invention relates to a packaging machine for wrapping light objects, for example paper cups in flexible plastics wrappers. The packaging machine according to the invention is of the general type including a cell conveyor for the objects, lower and upper plastics films respectively fed below and above the objects and welding and cutting means for joining said films together before each object by operating a double weld with intermediate cut. According to the invention, each cell of the conveyor is provided with at least one upper closing arm carrying an idle roller for the lower film and resiliently retained in cell closing position, there being provided first and second cam means acting on said arm to cause momentary displacements thereof into cell opening position when each cell passes through loading and discharge regions respectively upstream and downstream of the film joining region.