Method and a unit for producing blister packs by cutting a blister band

A unit (1) for producing blister packs (7) by cutting a blister band (4), the unit having conveying means (3) for feeding a band (4) having blisters (2) containing products, in a selected feeding direction (A) through subsequent stations for verifying said band (4), for closing said band (4) with a covering band, and to a cutting station (5), where the closed blister band (4) is cut;

• the unit further comprising:
• cutting means (30) situated in said cutting station (5) and acting on said closed blister band (4) to progressively shear said band so as to obtain blister packs (7) detached from at least one strip (9a, 9b) or from at least one longitudinal edge of said blister band (4);
• the cutting means (30) having at least one primary cutting section (34) and at least one secondary section (35);
• means for detecting if portions of said blister band (4) are faulty in a control station, said secondary cutting station (35) being made ineffective, so as to prevent detachment of the faulty blister packs (8), said faulty blister packs being destined to be rejected from said strip (9a, 9b) of said band (4);
• said cutting means (30) including punch means (32), which move with a reciprocating motion to and from motionless die means (38) in a direction substantially transversal to said feeding direction (A), in order to cut said band (4);
• said punch means (32) having said primary cutting section (34) and said secondary cutting section (35);
• said cutting means supporting further sectioning and cutting means (50) for forming cutting points (15a, 15b) on said strip (9a, 9b), while simultaneously cooperating with said die means (38) and with said punch means (32);
• and,
• said punch means (32) being movable alternatively between a rest position and a position defined by a maximum stroke (MAX) and through a position defined by an intermediate stroke (INT);
• said primary cutting section (34) being defined along a cutting area (33) of said punch means (32), along such an extension, as to be engaged with said die means (38) in a position corresponding to the maximum stroke (MAX), as well as in a position corresponding to the intermediate stroke (INT);
• said secondary cutting section (35) being defined along a cutting area (33) of said punch means (32), along such an extension, so as to engage with said die means (38) only in a position corresponding to said maximum stroke (MAX).