Machine and method for making filter bags for infusion products

摘要

A machine ( 1 ) for making filter bags ( 4 ) of tetrahedral shape for infusion products comprises a revolving conveyor drum ( 15 ) driven by a first drive shaft ( 16 ) to feed a web ( 5 ) of filter paper along a path (P) on which there are positioned: a station ( 25 ) for feeding the filter paper web ( 5 ); a station ( 21 ) for feeding a succession of tags ( 6 ); a station ( 22 ) for feeding tie string ( 7 ) connecting the filter bags ( 4 ) to the respective tags ( 6 ); a station ( 23 ) for arranging the tie string ( 7 ) according to a defined pattern on the path (P); and a plurality of sealers ( 24 ) facing the path (P) to attach the tie string ( 7 ) and the tags ( 6 ) to the filter paper web ( 5 ). The sealers ( 24 ) perform a defined movement between a sealing position and a waiting position, and this movement, which is performed simultaneously and synchronously by all the sealers ( 24 ), is imparted, through a transmission element ( 39 ) shared by all the sealers ( 24 ), by a second cam drive shaft ( 36 ) connected to the same source of motion ( 18 ) to which the first shaft ( 16 ) that drives the conveyor drum ( 15 ) is connected.