Transfer device for hollow bodies printed or to be printed in a printing machine

A transfer device for hollow bodies printed or to be printed in a printing machine such as sleeves, collapsible tubes, or cans, comprising:

• a first rotary driven transfer rotor for transferring hollow bodies, supplied sequentially by way of a supply conveyor means, to a rotary driven capstan plate associated with a printing device of the printing machine, having receiving capstans serving to hold the hollow bodies during a printing operation at a transfer zone
• and/or
• a second rotary driven transfer rotor for the transfer of already printed hollow bodies from the rotary driven capstan plate at a transfer zone between said transfer rotor and the capstan plate, in which the hollow bodies are transferred between receiving capstans of the capstan plate and receiving sites of the transfer rotor,
• wherein, each said transfer rotor comprises;
• a stationary stator;
• two discs respectively engaged on opposite ends of the stationary stator to rotate together around an axis of rotation of the transfer rotor;
• a plurality of guide means parallel to the axis of rotation slidably engaged between the two discs on guide rails, said guide rails extending out radially from a center of each of the discs;
• a plurality of holding units defining the receiving sites for holding the hollow bodies to be transferred, each of the holding units slidably engaged on each one of the guide means and arranged on the transfer rotor sequentially in a direction of rotation thereof;
• wherein the holding units move along a first curved path when the transfer rotor is rotating, and
• the receiving capstans move along a second curved path when the capstan plate is rotating,
• first control means for radially adjusting the guide means on the guide rails, so as to vary a pitch between the holding units in a direction perpendicular to the axis of rotation during rotation of the transfer rotor, and
• second control means for sliding the holding means on the guide means to a position coaxial with a receiving capstan during rotation of the transfer rotor;
• wherein the first control means includes two identical first cam curves respectively located on two axially oriented faces on the stator and a cam follower at opposite ends of each of the guide means respectively engaged to slide in the two identical cam curves, and
• wherein the second control means comprises a second cam curve on the periphery of the stator and a cam follower on each of the holding units slidably engaged in the second cam curve.