Machine tool for working sheet metal

A machine tool for working sheet metal comprising:

• an upper rotatable turret (7) supporting, in a ring, a plurality of translatable pins (11) each of which carries a tool (12) of the punching or nibbling type;
• a lower rotatable turret (14) parallel to and connected with the upper turret (7) and supporting, in a ring, a plurality of holders (15), the number of which is equal to the number of pins (11) and each of which supports a die (16) in such a way that each tool (12) has one die (16) associated therewith,
• a striker (6) operable to translate between an upper dead point and a lower dead point under the action of a transmission system which, in use, controls the pressure of said striker (6) on a head (24) of one of said pins (11) in such a way that the pin translates downwardly and the tool (12) associated therewith causes a cutting or nibbling of a portion of a metal sheet positioned over the die (16) associated therewith by entering into a hole (63) in said die (16), and electronic means (5) by which an operator can, in use, adjust the stroke of the said striker (6) and thereby a lower dead point and an upper dead point for each tool (12), said electronic means (15) including members (115) for identifying which tool (12) is involved in the adjustment, a first member (105) for adjusting the upper dead point of said striker (6) for each tool (12), a second member (112) for adjusting the lower dead point of said striker (6) for each tool (12) and a comparison member (75) for comparing the stroke as adjusted by means of the first (105) and second (112) adjustment members and the stroke which said striker (6) then performs on each tool (12) in such a way as to be able to control, by means of a first blocking member and a second blocking member (96) the stopping of the translation of the said striker (6).