Patent ID: 7194941

Claim:
A method of manufacturing perforated plaster boards on an apparatus comprising a punching device ( 6 ) for generation of the perforation and cutting stations ( 8 , 12 ) for cutting the sides of the boards to size; comprising the steps of: first grabs ( 16 ) fixed to move laterally with a first movable conveyor ( 15 ) seizing and fixing within a first side ( 17 ) of a non-perforated plaster board ( 14 ) and then pushing the plaster board ( 14 ) laterally in a first conveying direction into the punching device ( 6 ) to be punched; thereafter, second grabs ( 22 ) fixed to move laterally with a second movable conveyor ( 18 ) seizing and fixing within a second side ( 19 ) opposite the first side ( 17 ) of the punched plaster board ( 14 ), the first grabs ( 16 ) being released only after the second grabs ( 22 ) have seized the second side ( 19 ), the second grabs ( 22 ) then pulling the punched plaster board ( 14 ) in the first conveying direction through the first cutting station ( 8 ) where two opposite long sides ( 23 , 24 ) of the punched plaster board ( 14 ) are cut to size; thereafter, third grabs ( 26 ) fixed to move laterally with a third movable conveyor ( 25 ) seizing and fixing within a third side of the punched plaster board ( 14 ) that is displaced by 90° compared to the second side, the second grabs ( 22 ) being released only after the third grabs ( 25 ) have seized the punched plaster board ( 14 ), the third grabs ( 26 ) pulling the punched plaster board ( 14 ) through a second cutting station ( 12 ) in a second conveying direction ( 7 ) perpendicular to the first conveying direction ( 7 ) with the third side ( 19 ) and a fourth side ( 17 ) that are perpendicular to the first and second sides ( 23 , 24 ) being cut to size in a second cutting station.