Patent ID: 8151706

Claim:
An apparatus for safely operating at least two components movable relative to one another in a machine processing printing materials, the apparatus comprising: drive motors each driving a respective one of the movable components; speed signal generators each being associated with a respective one of said drive motors of the movable components for detecting speeds of the movable components; and at least one control computer for detecting movement of the movable components and for comparing the speeds of the movable components detected by said speed signal generators to each other, said at least one control computer connected to said speed signal generators for comparing the speeds of the movable components detected by said speed signal generators, said at least one control computer, upon a reduction in a spacing between the movable components, said reduction being detected by the comparison of the speeds of the movable components to each other, at a time when said drive motors are configured to maintain or increase said spacing between the movable components, bringing to a standstill at least one of the movable components causing said reduction in said spacing between the movable components.