Patent ID: 6035604
Filing Date: 2000-03-14
Classification: B29C,B29L,B65B

Abstract:
A packaging unit for continuously producing sealed packages, containing a pourable food product, from a tube made of heat-seal packaging material in sheet form, fed along a vertical supply path and filled with said food product, said unit comprising:a first chain conveyor having a plurality of first jaws and defining a first endless path of said first jaws;a second chain conveyor having a plurality of laterally shiftable second jaws and defining a second endless path of said second jaws;said first path and said second path respectively comprising a first work portion and a second work portion adjacent to said tube supply path extending substantially symmetrically on opposite sides of said supply path, so that said first jaws are maintained contacting respective said second jaws to grip said tube at respective equally spaced cross sections, and to perform, at said cross sections, respective sealing operations on the tube by heat-sealing the packaging material;monitoring means for monitoring at least said second jaws along said second work portion of said second path, to determine correct performance of said sealing operations, said monitoring means comprising fixed sensor means located at said second work portion and cooperating with each said second jaw to generate at least one monitoring signal related to an operating value of a quantity associated with said second jaw, and comparing means for comparing said operating value with at least one predetermined reference value of said quantity, and for generating a fault signal in the event of a predetermined relationship between said operating value and said reference value;wherein said fixed sensor means comprises:at least one first fixed sensor positioned at a first position along said second work portion, andat least one second fixed sensor located at a second position along said second work portion, said second position being spaced from said first position along said second work portion;said first fixed sensor and said second fixed sensor cooperating with said second jaw to generate at least two distinct monitoring signals related to an operating value of said quantity; andmeans for comparing said operating value related to said at least two distinct monitoring signals with a range of lateral shift values indicative of normal operation.