System for transferring tubular blanks in an open configuration to a supply line of a packing machine

A system for transferring tubular blanks in an open configuration to a supply line of a packing machine, the line being constituted by belts loop-wound on at least two crown wheels, a drive wheel and a driven wheel, to which belts an abutting segment and a thrust segment are perpendicularly fixed, alternatively from downstream to upstream, facing externally so as to define at an upper branch of the line, at which the abutting segment and the thrust segment are vertical, equidistanced compartments, the segments identifying, in a curved tract located upstream of the upper branch, in which the segments are radial with respect to an axis of the relative crown wheel, dynamic seatings, a dimension of which in a motion direction of the line is greater than a dimension thereof of a corresponding compartment, the system comprising:

• an apparatus for positioning a tubular blank in an open configuration intermittently in a zone situated in front of a head of the line defining the curved tract, the tubular blank being hooked to relative retaining means;
• a rotating member, activated in phase relation with a movement of the belts, arranged between longitudinal walls of the line at the head, coaxial with the crown wheel relative thereto, and provided with a series of transfer means which are angularly equidistanced, the transfer means having, in the tract facing towards the head, a corresponding dynamic seating for encountering, in the zone, a flap of the tubular blank, the tubular blank being freely inserted in the dynamic seating, and subsequently hooking the dynamic seating, as a consequence of activation of the transfer means which are actuated in phase relation with a deactivation of the retaining means, the transfer means being deactivated in proximity of the upper branch in phase relation with the arranging from radial to vertical of the abutting segment and the thrust segment delimiting the dynamic seating and the compartment corresponding to the dynamic seating, which, by the segments, retains the tubular blank and establishes an open tubular configuration thereof;
• the transfer means being positioned along a circumference tangential to the upper branch;
• a drum rotating with respect to an axis that is parallel to a rotation axis of the rotating member, peripherally exhibiting angularly-equidistanced work stations, each of the work stations being provided with retaining means;
• the drum being supported by a structure for translating the drum in a direction defined by a line joining axes respectively of the drum and the rotating member, enabling transit into the zone of the work stations upon a varying of a format of the tubular blanks;
• movements of the drum and the rotating member being such that, in the zone, the retaining means of a work station transiting said zone and the transfer means of the rotating member are arranged aligned on a same plane that is diametral both for the drum and for the rotating member.