Apparatus for electrically perforating sheet material

Claim 1

An apparatus for perforating rows of holes in a moving web, each row being perpendicular to the direction of movement of said web comprising: a. a frame; b. a ground shaft mounted for rotation on said frame, said shaft being insulated from said frame; c. a drum secured to said shaft, the axis of said drum being perpendicular to the direction of movement of said web, said moving web contacting the surface of said drum, said drum including an internal core of a conductive material surrounded by an insulative cover and at least one blade of conductive material contacting said core and extending outwardly therefrom so that the edge of said blade is exposed on the peripheral surface of said drum, said edge being parallel to the axis of said drum; d. a plurality of electrodes positioned around a portion of said drum, said electrodes being arranged in a spiral pattern transverse to the direction of said web and the tips of said electrodes forming the outline of an arc surrounding said portion of said drum; e. means for mounting said electrodes on said frame; and, f. means for applying a pulsing voltage to said electrodes, said means for applying said pulsing voltage being synchronized with the rotation of said drum so that the voltages are applied to said electrodes as said blade passes each electrode, whereby a single, electrical discharge arc occurs between said blade and said electrode closest to said blade to perforate the web and from form row of holes in the web which is perpendicular to the edge of the web.

Claim 2

An apparatus for perforating rows of holes in a moving web, each row being perpendicular to the direction of movement of said web comprising: a. a frame; b. a ground shaft mounted for rotation on said frame, said shaft being insulated from said frame; c. a drum secured to said shaft, the axis of said drum being perpendicular to the direction of movement of said web, said moving web contacting the surface of said drum, said drum including an internal core of a conductive material surrounded by an insulative cover and at least one blade of conductive material contacting said core and extending outwardly therefrom so that the edge of said blade is exposed on the peripheral surface of said drum, said edge being parallel to the axis of said drum; d. a plurality of electrodes positioned around a portion of said drum, said electrodes being arranged in a spiral pattern transverse to the direction of said web and the tips of said electrodes forming the outline of an arc surrounding said portion of said drum; e. means for mounting said electrodes on said frame; and, f. means for applying a pulsing voltage to said electrodes, said means for applying said pulsing voltage being synchronized with the rotation of said drum so that the voltages are applied to said electrodes as said blade passes each electrode, whereby a single, electrical discharge arc occurs between said blade and said electrode closest to said blade to perforate the web and from form row of holes in the web which is perpendicular to the edge of the web.

Claim 5

An apparatus for perforating groups of holes in a moving web, each group having two rows of holes which are perpendicular to the direction of movement of said web, said groups being spaced longitudinally along the length of said web, comprising: a. a frame; b. a grounded shaft mounted for rotation on said frame, said shaft being insulated from said frame; c. a drum secured to said grounded shaft, the axis of said drum being perpendicular to the direction of movement of said web, said moving web contacting this surface of said drum, said drum including an internal core of conductive material surrounded by an insulative cover and at least two sets of two blades of conductive material contacting said core and extending outwardly therefrom so that the edges of said blades are exposed on the peripheral surface of said drum; d. a plurality of electrodes positioned around a portion of said drum, said electrodes being arranged in a spiral pattern transverse to the direction of movement of said web and the tips of said electrodes forming the outline of an arc surrounding a portion of said drum, said web passing between said drum surface and said tips of said electrodes and the transverse offset space between adjacent electrodes corresponding to the perpendicular space between adjacent holes in a row on said web and the longitudinal spacing between said rows of holes on said web corresponding to the circumferential spacing between said blades on said drum; e. means for mounting said electrodes on said frame; and f. means for applying a pulsing high voltage charge to said electrodes, said pulsing voltage means being synchronized with the rotation of said drum so that at least two high voltage charges are applied to said electrodes as each set of blades passes each electrode, whereby a single electrical discharge will occur between each blade in tHe set and each electrode to perforate the web.

Claim 6

An apparatus for perforating groups of holes in a moving web, each group having two rows of holes which are perpendicular to the direction of movement of said web, said groups being spaced longitudinally along the length of said web, comprising: a. a frame; b. a grounded shaft mounted for rotation on said frame, said shaft being insulated from said frame; c. a drum secured to said grounded shaft, the axis of said drum being perpendicular to the direction of movement of said web, said moving web contacting this surface of said drum, said drum including an internal core of conductive material surrounded by an insulative cover and at least two sets of two blades of conductive material contacting said core and extending outwardly therefrom so that the edges of said blades are exposed on the peripheral surface of said drum; d. a plurality of electrodes positioned around a portion of said drum, said electrodes being arranged in a spiral pattern transverse to the direction of movement of said web and the tips of said electrodes forming the outline of an arc surrounding a portion of said drum, said web passing between said drum surface and said tips of said electrodes and the transverse offset space between adjacent electrodes corresponding to the perpendicular space between adjacent holes in a row on said web and the longitudinal spacing between said rows of holes on said web corresponding to the circumferential spacing between said blades on said drum; e. means for mounting said electrodes on said frame; and f. means for applying a pulsing high voltage charge to said electrodes, said pulsing voltage means being synchronized with the rotation of said drum so that at least two high voltage charges are applied to said electrodes as each set of blades passes each electrode, whereby a single electrical discharge will occur between each blade in tHe set and each electrode to perforate the web.