Cutter for cutting sheets from a web

Claim 2

A cutting arrangement for cutting sheets from a continuously fed web, comprising, in combination, a pair of cutter blades respectively arranged on opposite sides of said fed web rotatable about axes extending substantially parallel to said fed web, said cutter blades having helical cutting edges extending along helixes having different leads and engaging each other along a cutting line; and drive means for rotating said cutter blades in opposite directions at different peripheral speeds, the ratio of which is equal to the ratio of said different leads of said helixes along which said helical cutting edges extend.

Claim 3

A cutting arrangement as set forth in claim 1 and including a pair of cutter rolls rotatable about said axes, said cutter blades being respectively fixed to said cutter rolls for rotation therewith about said axis, at least one of said blades having a cutting edge projecting beyond the peripheral surface of the respective roll.

Claim 4

A cutting arrangement as set forth in claim 2, in which the cutter blades of said cutter rolls have linear cutting edges, the diameter of an imaginary flight cylinder described by said cutting edge of at least one of said cutter rolls being smaller than the diameter of cylindrical surface portions of said one cutter roll, which cylindrical surface portions are disposed between a plurality of at least three flats which are formed on said one cutter roll, one of said flats lying in an imaginary plane which intersects the cutter blade of said flattened cutter roll, said flats being provided in a number which is at least three and exceeds by one the integral number representing the ratio of the surface velocities imparted to the cutter rolls owing to their different speeds.

Claim 5

A cutting arrangement as set forth in claim 2, in which at least one of said cutter rolls is formed with flats which are set back from a cylindrical surface which is defined in part by cylindrical surface portions at said one cutter roll, one of said flats lying in an imaginary plane which intersects the cutter blade of said flattened cutter roll, said cutter further comprising a resiliEnt, stationary scraper which engages said cutter roll formed with said flats.

Claim 6

A cutting arrangement as set forth in claim 2, in which at least one of said cutter rolls is formed with flats which are set back from a cylindrical surface which is defined in part by cylindrical surface portions of said one cutter roll, one of said flats lying in an imaginary plane which intersects the cutter blade of said flattened cutter roll, said cutter further comprising a leaf spring disposed adjacent to that of said flats which intersects the cutter blade on said flattened cutter roll, said leaf spring succeeding the cutter blade of said flattened cutter roll in the direction of rotation thereof, the length of said leaf spring in a direction which is parallel to the axis of rotation of the associated cutter roll being equal to the dimension of said flattened cutter in said direction, means for gripping said leaf spring at a portion which is remote from the cutting edge of said cutter blade of said one cutter roll, said gripping means being disposed within the imaginary flight cylinder which is described by said cutting edge of said cutter blade during the rotation of said cutter roll, said leaf spring having a resilient width portion which is adjacent to said cutting edge and disposed outside said imaginary flight cylinder and adapted to be urged back into said imaginary slide cylinder by the cutter blade of the other cutter roll.

Claim 7

A cutting arrangement as set forth in claim 1, wherein the ratio of the peripheral speeds of said two cutter blades equal an integer other than one.

Claim 8

A cutting arrangement as set forth in claim 2, said drive means comprising drive shafts which form part of said cutter rolls and gears rigidly connected to said drive shafts, the number of teeth of the gear which is connected to the drive shaft of one cutter roll is lower than the number of teeth of the gear which is connected to the drive shaft of the other cutter roll in such a ratio that the integral number of complete revolutions performed by said one cutter roll exceeds the integral number of the complete revolutions performed by the other cutter roll in the same period of time.

Claim 9

A cutting arrangement as set forth in claim 1, in which said drive means are adapted to impart to one of said cutter blades an integral number of at least two complete revolutions during a complete revolution of the other cutter blade.