Patent ID: 8246879

Claim:
A method of rubber-coating an annular surface ( 2 ) of a tire toroidal body ( 3 ); the method comprising the steps of: issuing a continuous rod ( 11 ) of elastomeric material from an emitting device ( 10 ); feeding the rod ( 11 ) automatically to a user unit ( 8 ) by a feed line ( 15 ) comprising at least one powered portion ( 16 ; 18 ) and a take-up unit ( 21 ) arranged upstream from the powered portion ( 16 ; 18 ) to apply a tension to the rod ( 11 ) and to compensate for any difference in the travelling speed of rod ( 11 ) upstream and downstream from take-up unit ( 21 ); and applying, at the user unit ( 8 ), the rod ( 11 ) to the annular surface ( 2 ) of the tire toroidal body ( 3 ); wherein the step of feeding the rod ( 11 ) to the user unit ( 8 ) comprises the further steps of: pushing, when the process is started for the first time, the rod by means of the emitting device ( 10 ) to move a front end portion of the rod ( 11 ) toward the powered portion ( 16 ; 18 ) of the feed line ( 15 ) along and above a supporting device ( 22 ) of the take unit ( 21 ) arranged upstream from the powered portion ( 16 ; 18 ), the supporting device ( 22 ) comprising a plurality of middle rollers ( 27 ) between a plurality of outside rollers ( 23 ) defining, for the rod ( 11 ), a coplanar first path (P 1 ) of given fixed length; keeping the supporting device ( 22 ) of the take-up unit ( 21 ) in a rest position that does not apply any tension to the rod ( 11 ) until the rod ( 11 ) is not firmly engaged by the powered portion ( 16 ; 18 ) arranged downstream from the take-up unit ( 21 ); moving, once the front end portion of the rod ( 11 ) reaches and is engaged by the powered portion ( 16 ; 18 ) of the feed line ( 15 ), only the middle rollers ( 27 ) of the supporting device ( 22 ) to form a window ( 45 ) between the outside rollers ( 23 ) at an intermediate portion of the supporting device ( 22 ); and deviating the rod ( 11 ) through the window ( 45 ) by means of a take-up device ( 40 ) that rests on the rod ( 11 ) to feed the rod ( 11 ) along a U-shaped second path (P 2 ) extending inside the window ( 45 ) and comprising a bend ( 46 ) of variable length for tensioning the rod ( 11 ) once the front end portion of the rod ( 11 ) reaches and is engaged by the powered portion ( 16 ; 18 ) of the feed line ( 15 ).