In-line punching machine

A paper punching machine comprising:

• a U-shaped guide member including a first member, a second member, and a set of rollers, the first and second members defining a material pathway therebetween for transporting a piece of paper along a direction of travel, wherein the rollers are sized and configured to engage the piece of paper to transport the piece of paper through the guide member;
• a first sensor element disposed adjacent the material pathway for detecting a trailing edge of the piece of paper a first time as the piece of paper moves through the material pathway, the first sensor element including a plurality of sensors arranged in a row perpendicular to the direction of travel;
• a second sensor element disposed adjacent the material pathway for detecting the trailing edge of the piece of paper a second time as the piece of paper moves through the material pathway;
• and
• a punch element including a plurality of punch pins sized to punch a first set of apertures in the piece of paper in a middle portion of the piece of paper based on detection of the trailing edge by the first sensor, and to subsequently punch a second set of apertures in the piece of paper adjacent the trailing edge based on detection of the trailing edge by the second sensor, wherein the punch element punches the first set of apertures prior to detection of the trailing edge by the second sensor.

A method of operating a punching machine comprising:

• directing a piece of material along a direction through a material pathway in the machine;
• detecting an edge of the piece of material a first time with a first sensor disposed adjacent the material pathway;
• punching a first set of apertures into the piece of material based on detection of the edge with the first sensor;
• detecting the edge of the piece of material a second time with a second sensor disposed adjacent the material pathway, subsequent to punching the first set of apertures;
• and
• punching a second set of apertures in the piece of material based on detection of the edge with the second sensor, subsequent to detecting the edge of the piece of material the second time with the second sensor.