A packaging machine includes a clamping arrangement, composed of a series of clamps designed to grip and release a web of flexible material, and which are coupled to a belt that is advanced along a predetermined path to advance the web of flexible through the machine. The belt is made up of side-by-side belt portions that are spliced together in axially spaced locations by the clamps, to withstand the forces and stresses placed thereon as the web material is advanced. Each clamp is formed of an upper jaw member and a lower jaw member that are pivotably interconnected together, in combination with a guide member the guides movement of the belt through the machine. The belts are independently driven by operation of a pair of motors, which are synchronously operated in order to advance the opposite edges of the web material at the same rate of speed through the machine.