Dosing device for feeding an infusion product

Abstract

A dosing device ( 1 ) for feeding an infusion product comprises a rotary drum ( 2 ) positioned between a web ( 3 ) of filter material and a hopper ( 4 ) for containing the infusion product; the drum ( 2 ) having a plurality of radial cells ( 5 ) made in it for containing the infusion product and in which there slide piston type dosing means ( 6 ); each dosing piston ( 6 ) being driven axially by respective eccentric cam actuating means ( 7 ) between two end positions, one of which corresponds to a top dead centre (PMS) where each dosing cell ( 5 ) faces the hopper ( 4 ) in order to receive a quantity of the infusion product, and the other corresponds to a bottom dead centre (PMI) where the dosing cell ( 5 ) faces the web ( 3 ) of filter material in order to discharge the quantity of infusion product onto the web ( 3 ) of filter material. Between the actuating means ( 7 ) and each piston ( 6 ) there are crank mechanisms ( 8 ) designed to act coaxially on the piston ( 6 ) in such a way as to enable the piston ( 6 ) to move in a direction that is perfectly aligned with a longitudinal axis (Z) of the respective dosing cell ( 5 ).

1 . A dosing device ( 1 ) for feeding an infusion product comprising a rotary drum type conveyor means ( 2 ) positioned between a web ( 3 ) of filter material and a hopper ( 4 ) for containing the infusion product; the drum type conveyor means ( 2 ) having a plurality of radial cells ( 5 ) made in them for containing the infusion product and in which there slide piston type dosing means ( 6 ); each dosing piston ( 6 ) being driven axially by respective eccentric cam actuating means ( 7 ) between two end positions, one of which corresponds to a top dead centre (PMS) where each dosing cell ( 5 ) faces the hopper ( 4 ) in order to receive a quantity of the infusion product, and the other corresponds to a bottom dead centre (PMI) where the dosing cell ( 5 ) faces the web ( 3 ) of filter material in order to discharge the quantity of infusion product onto the web ( 3 ) of filter material; the device being characterised in that between the actuating means ( 7 ) and each piston ( 6 ) there are crank mechanisms ( 8 ) designed to act coaxially on the piston ( 6 ) in such a way as to enable the piston ( 6 ) to move in a direction that is perfectly aligned with a longitudinal axis (z) of the respective dosing cell ( 5 ).  
   
   
       2 . The device according to  claim 1 , characterised in that the eccentric cam actuating means ( 7 ) comprise at least one cam track ( 7   a ) in which there runs a cam follower ( 7   b ) for each piston ( 6 ) the crank mechanisms ( 8 ) comprising a first crank ( 10 ) connected at one end to the cam follower ( 7   b ) and, at the other end, to a transmission shaft ( 11 ); the transmission shaft ( 11 ) being rigidly attached to a first end of a second crank ( 13 ) that is in turn connected at its other end to a first end ( 14   a ) of a connecting control rod ( 14 ); the connecting rod ( 14 ) being linked to the piston ( 6 ).  
   
   
       3 . The device according to  claim 2 , characterised in that a first end of the second crank ( 13 ) is rigidly attached to the shaft ( 11 ) in such a way as to enable transmission of motion between the cam follower ( 7   b ) and the piston ( 6 ).  
   
   
       4 . The device according to  claim 2  or  3 , characterised in that the end of the second crank ( 13 ) that is linked to the connecting rod ( 14 ) is fork-shaped so as to hold the end of the connecting rod ( 14 ) on both sides; the connecting rod ( 14 ) being coupled with the second crank ( 13 ) through a first pin ( 16 ) that passes through a respective hole ( 17 ) made in said forked end.  
   
   
       5 . The device according to  claim 4 , characterised in that the connecting rod ( 14 ) is linked to the piston ( 6 ) by a second, transversal pin ( 18 ) which is housed in a respective hole ( 19 ) made in the piston ( 6 ) and which engages the respective end of the connecting rod ( 14 ).