Drive for a cylinder of a rotary printing machine

1. A drive system for a folder of a rotary printing machine, said folder comprising a folding cylinder and a folding jaw cylinder, said folding cylinder comprising a first cylinder part bearing a holding element and a second cylinder part bearing folding blades, said folding jaw cylinder comprising a first cylinder part, said first and second cylinder parts of said folding cylinder being rotated independently of one another about a common axis, said drive system comprising

a spur gear fixed to said second cylinder part of said folding cylinder and a spur gear fixed to said first cylinder part of said folding jaw cylinder, said spur gears being directly engaged, and

first and second electric motors for driving respective said first and second cylinder parts of said folding cylinder independently of one another.

2. A drive system as in claim 1 wherein said folding jaw cylinder comprises first and second cylinder parts which each bear folding jaws, said folder further comprising a gripper folding blade cylinder comprising a first cylinder part bearing grippers and a second cylinder part bearing folding blades, said drive system further comprising

a spur gear fixed to said second cylinder part of said folding jaw cylinder and a spur gear fixed to each of said first and second cylinder parts of said gripper folding blade cylinder, said spur gear of said first cylinder part of said folding jaw cylinder directly engaging said spur gear of said first cylinder part of said gripper folding blade cylinder, said spur gear of said second cylinder part of said folding jaw cylinder directly engaging said spur gear of said second cylinder part of said gripper folding blade cylinder, and

a third electric drive motor for driving said second cylinder parts of said folding jaw cylinder and said gripper folding blade cylinder.

3. A drive system as in claim 1 wherein said folder further comprises a knife cylinder, said drive system further comprising

a spur gear fixed to said first cylinder part of said folding cylinder and a spur gear fixed to said knife cylinder, said spur gear fixed to said first cylinder part of said folding cylinder and said spur gear fixed to said knife cylinder being directly engaged, and

a pinion belonging to said first electric motor, said pinion engaging in one of said spur gear fixed to said first cylinder part of said folding cylinder and said spur gear fixed to said knife cylinder.

4. A drive system as in claim 1 further comprising a position control system comprising a computing and memory unit in which preset angular positions of said cylinders are stored, said computing and memory unit being connected to said electric motors.

5. A drive system as in claim 1 further comprising stops arranged on each of said first and second cylinder parts, said stops limiting relative rotatability of said cylinder parts.

6. A drive system as in claim 1 further comprising hardware limit switches arranged on each of said first and second cylinder parts, said hardware limit switches limiting relative rotatability of said cylinder parts.

7. A drive system as in claim 4 wherein said computing and memory unit stores limiting values for the relative angular offset of the cylinder parts of each said cylinder in order to limit the relative rotatability of the cylinder parts of the cylinder parts of each said cylinder.

8. A rotary printing machine comprising a folder comprising a folding cylinder and a folding jaw cylinder, said folding cylinder comprising a first cylinder part bearing a holding element and a second cylinder part bearing folding blades, said folding jaw cylinder comprising a first cylinder part, said first and second cylinder parts of said folding cylinder being rotated independently of one another about a common axis, said drive system comprising:

a spur gear fixed to said second cylinder part of said folding cylinder and a spur gear fixed to said first cylinder part of said folding jaw cylinder, said spur gears being directly engaged; and

first and second electric motors for driving respective said first and second cylinder parts of said folding cylinder independently of one another.

9. A rotary printing machine as in claim 8 wherein said folding jaw cylinder comprises first and second cylinder parts which each bear folding jaws, said folder further comprising a gripper folding blade cylinder comprising a first cylinder part bearing grippers and a second cylinder part bearing folding blades, said machine further comprising:

a spur gear fixed to said second cylinder part of said folding jaw cylinder and a spur gear fixed to each of said first and second cylinder parts of said gripper folding blade cylinder, said spur gear of said first cylinder part of said folding jaw cylinder directly engaging said spur gear of said first cylinder part of said gripper folding blade cylinder, said spur gear of said second cylinder part of said folding jaw cylinder directly engaging said spur gear of said second cylinder part of said gripper folding blade cylinder; and

a third electric drive motor for driving said second cylinder parts of said folding jaw cylinder and said gripper folding blade cylinder.

10. A rotary printing machine as in claim 8 wherein said folder further comprises a knife cylinder, said drive system further comprising:

a spur gear fixed to said first cylinder part of said folding cylinder and a spur gear fixed to said knife cylinder, said spur gear fixed to said first cylinder part of said folding cylinder and said spur gear fixed to said knife cylinder being directly engaged; and

a pinion belonging to said first electric motor, said pinion engaging in one of said spur gear fixed to said first cylinder part of said folding cylinder and said spur gear fixed to said knife cylinder.

11. A rotary printing machine as in claim 8 further comprising a position control system comprising a computing and memory unit in which preset angular positions of said cylinders are stored, said computing and memory unit being connected to said electric motors.

12. A rotary printing machine as in claim 8 further comprising stops arranged on each of said first and second cylinder parts, said stops limiting relative rotatability of said cylinder parts.

13. A rotary printing machine as in claim 8 further comprising hardware limit switches arranged on each of said first and second cylinder parts, said hardware limit switches limiting relative rotatability of said cylinder parts.

14. A drive system as in claim 11 wherein said computing and memory unit stores limiting values for the relative angular offset of the cylinder parts of each said cylinder in order to limit the relative rotatability of the cylinder parts of the cylinder parts of each said cylinder.