Patent ID: 7472635

Claim:
A blade holder for a cutting machine, comprising: a blade head held on a raising and lowering device, wherein said blade head is provided with a circular blade; an adjustment mechanism for said circular blade, wherein for a movement of said circular blade between a cutting position and a ready position, said adjustment mechanism is provided with an adjustment piston rod having an adjustment piston that is guided in a chamber of a housing of said blade head and that is adapted to be moved by compressed air, and wherein a piston surface of said adjustment piston is effective in a direction of adjustment and has a cross-sectional area that is different in different positions of said adjustment piston such that as a path of said adjustment piston in said direction of adjustment increases, said piston surface that is acted upon by compressed air increases in a continuous manner, wherein a membrane is secured to an outer wall of said chamber, wherein said piston surface of said adjustment piston that is acted upon by compressed air is formed by said membrane, and wherein said outer wall of said chamber continuously conically widens in said direction of adjustment such that as said path of said adjustment piston increases in said direction of adjustment, said membrane rolls off on said widening outer wall thereby continuously increasing the membrane surface which is effective as said piston surface; and a compression spring for biasing said adjustment piston rod into said ready position of said circular blade.