Patent ID: 6283471
Filing Date: 2001-09-04
Classification: B65H

Abstract:
A method of controlling sheet feed to a sheet-processing machine, wherein sheets are separated from a pile, conveyed onto a table, brought individually into contact with alignment lays for leading edges of the sheets, and conveyed onward therefrom individually for processing in the machine, which comprises, upon misalignment of a sheet, generating a signal by ultrasonic detectors active in transmission operation, the ultrasonic detectors being fixedly disposed parallel to and upline from the alignment lays and including two ultrasonic transmitters arranged at a defined distance, and ultrasonic receivers associated therewith, maintaining over the area of a measuring window sonic energy flux originating from the ultrasonic transmitters, respectively, at a substantially constant sonic intensity in the conveying direction of the sheets, integrally detecting by the respective ultrasonic receiver the sonic energy passing through the measuring window, and simultaneously measuring a difference in the sonic energy measured by the ultrasonic receivers.