A machine for forming sheets by longitudinal stretching, said machine (1) comprising:
- a support frame (3);
- a forming tool (4) for the sheet;
- a first chassis (10) and a second chassis (10) mounted on the support frame (3) respectively on first and second sides of the forming tool (4);
- a first stretching cylinder (9) and a second stretching cylinder (9);
- first and second support structures (8);
- a first tipping axis (11) and a second tipping axis (11) associated respectively with each of the first and second support structures (8), a vertical position of each of the first tipping axis and the second tipping axis being vertically adjustable;
- a first tipping cylinder (12) inserted between the first chassis (10) and the first support structure (8), the first support structure (8) being mounted at said first tipping cylinder (12) to thereby allow for a pivoting maneuver of said first support structure (8) about said first tipping axis (11);
- a second tipping cylinder (12) inserted between the second chassis and the second support structure (8), the second support structure (8) being mounted at said second tipping cylinder (12) to thereby allow for a pivoting maneuver of said second support structure (8) about said second tipping axis (11);
- a first stretch head (2) and a second stretch head (2′) located respectively on the first and second sides of the forming tool (4),
- said first and second stretch heads (2, 2′) comprising respectively a first line of grippers (5) integral with the first support structure (8) and a second line of grippers (5) integral with the second support structure (8),
- the first support structure (8), the first stretching cylinder (9), and the first line of grippers (5) being mounted at the first tipping axis (11) on the first chassis (10),
- the second support structure (8), the second stretching cylinder (9), and the second line of grippers (5) being mounted at the second tipping axis (11) on the second chassis (10),
- said first chassis (10) and said support frame (3) being mounted together at a third tipping axis (13);
- a third tipping cylinder (14) being inserted between said first chassis (10) and said support frame (3),
- the third tipping axis (13) being parallel to the first tipping axis (11),
- the third tipping axis (13) and the third tipping cylinder (14) allowing for a maneuver in rotation of said first chassis (10) about said third tipping axis (13) to thereby vertically adjust the vertical position of said first tipping axis (11),
- said second chassis (10) and said support frame (3) being mounted together at a fourth tipping axis (13);
- and
- a fourth tipping cylinder (14) being inserted between said second chassis (10) and said support frame (3), the fourth tipping axis (13) being parallel to the second tipping axis (11),
- the fourth tipping axis (13) and the fourth tipping cylinder (14) allowing for a maneuver in rotation of said second chassis (10) about said fourth tipping axis (13) to thereby vertically adjust the vertical position of said second tipping axis (11).