Patent ID: 7299600

Claim:
A device for sealing filter bags for products for infusion, 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, the device comprising: a sealer sonotrode facing a first path along which the flat web is fed to seal the string, which is arranged according to a defined pattern, and the tag to each other and to the flat web of filter paper; drive means for imparting to the sealer sonotrode a defined motion towards and away from a sealing position, the drive means comprising: first means acted upon by the sealer sonotrode and designed to apply a predetermined force to the sealer sonotrode; second means for opposing the force of the first means and reducing an intensity thereof; and third means for disabling the second means during predetermined steps of passing the filter bag components under the sealing sonotrode element, and permitting a predetermined sealing contact, wherein the first and second means define a part of a four-point linkage.