Patent ID: 7204794

Claim:
A machine for making filter bags for infusion products, each filter bag being made from a flat web of filter paper and having applied to it a tag and a tie string connecting the tag to the filter bag, wherein the machine comprises: conveyor means for feeding the flat web of filter paper along at least part of a first path defined by the conveyor means; a first drive shaft for imparting rotary motion to the conveyor means; a first station for feeding the flat web of filter paper to the first path; a second station for feeding a succession of the tags to the first path; a third station for feeding the tie string to the first path; a fourth station for arranging the tie string according to a defined pattern on the first path; sealing means facing the first path and designed to attach the tie string, arranged according to said pattern, and the tags to each other and to the flat web of filter paper by sealing; a drive device for imparting to the sealing means a defined motion towards and away from a sealing position; a source of motion shared by the first drive shaft and the drive device; a station for forming the filter bags from the flat web of filter paper to which the tags and tie string have already been applied; a second drive shaft connected to the shared source of motion; a transmission element positioned between the second drive shaft and the sealing means, wherein said seating means comprises a plurality of sealers positioned along the first path and each having a sealing end facing the first path; the transmission element being shared by all the sealers in order to move the respective sealing end along a respective second closed path comprising a sealing section that substantially coincides with the first path and a return section extending outside the first path.