Offset printing machine having two printing units

An offset printing machine having two printing units comprising:

• a first printing unit comprising a front frame (25), a rear frame (25'), a first impression cylinder (5), and a first chain delivery unit (8) having an endless chain (12) and a driven shaft (10) rotatably supported by the front and rear frames (25 25');
• a second printing unit comprising a second front frame (26), a second rear frame (26'), and a second impression cylinder (14);
• a tension control means for controlling tension of the endless chain (12), the tension control means comprising a pair of first and second bearing holders (28 29) for supporting the driven shaft (10) and movable relative to the front and rear frames (25 25') in a tension oontrolling direction;
• a linking holder (30) provided integral with the first bearing holder (28), and a pivot holder (31) provided integral with the second bearing holder (29);
• means for pivoting the second printing unit (2), the pivoting means comprising the pivot holder (31), a first holder (45) fixed to the second rear frame (26'), a pivot bolt (27) supported on the first holder (45) and engageable with the pivot holder (31);
• and
• means for connecting the second unit (2) to the first unit (1), the connecting means comprising the linking holder (30), a second holder (42) fixed to the second front frame (26) end a linking pin (44) supported by the second holder (42) and engageable with the linking holder (30).