摘要 |
<p>A method and apparatus or detecting jam-ups of serially advancing blanks of which the method comprises storing a number corresponding to the length of the blanks in predetermined increments, detecting a leading edge of such blanks, actuating a control means by the detection of the leading edges which generates a digit corresponding to the predetermined increments, detecting a trailing edge of such blanks to deactuate the control means, comparing the stored number with the digits generated by the control means, and stopping the blanks when the number of digits exceeds the stored number. Apparatus for carrying out the foregoing method preferably includes a storage circuit for the number corresponding to the blank length, a detector for detecting the leading and trailing edges of the blanks, a control means responsive to the detector for generating and storing digits corresponding to the blank length passing the detector, and a comparison circuit to determine when the number of digits exceeds the stored number and stopping the advance of blanks when this occurs.</p> |