Rotary punch device with push-pull chip removal

Claim 2

A rotary punching device of the type comprising a punch roll with a protruding hollow punch that cooperates with a back-up roll to punch chips from a web of sheet material that is advanced through the nip of said rolls, characterized in that both said rolls are provided with ducts that open through their respective peripheries and are registerable during a punching operation, one of said ducts including the aperture in the hollow punch, and means including respective openings in said rolls communicating with said ducts for conveying fluid under pressure to one of said openings and applying a vacuum to the other of said openings, such that the chip punched out from the web is directed into one of said rolls and removed by a push-pull operation.

Claim 3

A device according to claim 1, further characterized in that the pressure fluid is conveyed via the opening in the back-up roll and the vacuum is applied via the opening in the punch roll so the chip will be removed by withdrawal through the aperture in the hollow punch.

Claim 4

A device according to claim 2, further characterized in that the pressure fluid and vacuum cooperate to deflect the initially pierced leading portion of each chip into said aperture prior to complete severance of the chip from the web.

Claim 5

A rotary punching device for punching out chips from a web of paper or the like, said device comprising a punch roll comprising a hollow punch element projecting radially from the outer periphery thereof and having an aperture communicating with an internal opening, a back-up roll having a port that opens through the outer periphery thereof and is intermittently registerable with the aperture during a punching operation, positive drive means for rotating said rolls in synchronism for causing such intermittent registration of the aperture and port as the web is advanced between said rolls, means for conveying fluid under pressure to the port in said back-up roll, and means for applying vacuum to the aperture via the opening in the punch roll, the port and aperture being so configured that as the chip is severed from the web, it will be successively deflected into and then conveyed away from the punch station via said aperture and opening. A device according to claim 4 further characterized in that said punch element is so disposed in relation to the web as to cause chips to be cut from one side edge of the web.

Claim 6

A device according to claim 4, wherein said means for conveying fluid under pressure includes a hollow drive shaft constantly communicating with an aligned bore provided in the back-up roll and connected to said port, and a rotary seal unit interposed between the drive shaft and fluid supply line.