Cutting-and creasing-wheel assembly, and a method for cutting and creasing a compressible material

1. A cutting- and creasing-wheel assembly comprising:

a pair of creasing-wheels of equal radial dimensions, arranged axially separated and rotating with their centers located on a common axis of rotation, and narrowly spaced to create a singular creasing line in a compressible web material;

a circular cutting-wheel journalled for rotation between the creasing-wheels at an axis of rotation which is separate and arranged displaceable from said axis of rotation through the centers of the creasing-wheels;

the cutting-wheel having a cutting edge on its periphery at a radius which is less than the radius of the creasing-wheels, wherein

the cutting-wheel is controllable, through displacement of its axis of rotation, to move between the creasing-wheels from a non-operative position radially inside the outer peripheries of the creasing-wheels to an operative position wherein the cutting edge projects radially outside said outer peripheries, whereby the cutting- and creasing-wheel assembly is controllable simultaneously to perform cutting and creasing at substantially the same point of contact with the web material.

2. The cutting- and creasing-wheel assembly of claim 1 , wherein the creasing wheels are ring-shaped and of equal outer and inner radial dimensions, the inner peripheries of the creasing-wheels journalled on rollers on which the creasing-wheels are arranged axially separated and freely rotating with their centers located on a common axis of rotation.

3. The cutting- and creasing-wheel assembly of claim 2 , wherein the cutting-wheel is journalled on a pivot for free rotation between the creasing-wheels.

4. The cutting- and creasing-wheel assembly of claim 3 , wherein the cutting-wheel is journalled on a pivot connected with an air-actuated piston/cylinder unit controlling the cutting-wheel in a movement in a substantially radial direction of the creasing-wheels.

5. The cutting- and creasing-wheel assembly of claim 4 , wherein the creasing-wheels and the cutting-wheel are supported in a lifter assembly which is guided for movements substantially perpendicular to a web material to be processed by the cutting- and creasing-wheel assembly, and which is operated by a power unit that controls the operative positions of the cutting- and creasing-wheel assembly.

6. The cutting- and creasing-wheel assembly of claim 5 , wherein the lifter assembly comprises a rod that is guided in the carrier to move in vertical directions, the rod in a top end supporting a first roller and in a lower end supporting second and third rollers on which the creasing-wheels are journalled for free rotation.

7. The cutting- and creasing-wheel assembly of claim 6 , wherein the lifter assembly comprises a rod which in its lower end supports the piston/cylinder units connected to the pivot on which the cutting-wheel is journalled for free rotation.

8. The cutting- and creasing-wheel assembly of claim 7 , wherein the lifter assembly comprises a rod which in its lower end carries a horizontal girder member carrying the piston/cylinder units which are connected to the cutting-wheel pivot, the girder connected to two air actuated piston/cylinder units acting between the girder and the carrier.

9. The cutting- and creasing-wheel assembly of claim 1 , wherein the outer peripheries of the creasing-wheels are rounded towards the sides facing outward from the cutting-wheel, whereas the sides facing inward connect more sharply to the peripheries.

10. The cutting- and creasing-wheel assembly of claim 1 , wherein the cutting edge runs continuously about the periphery of the cutting-wheel.

11. The cutting- and creasing-wheel assembly of claim 1 , wherein the cutting edge runs serrated about the periphery of the cutting-wheel.

12. The cutting- and creasing-wheel assembly of claim 1 , wherein the cutting-wheel is journalled on a pivot for free rotation between the creasing-wheels.

13. A method of forming slits and creases in a compressible web material, comprising the steps of

providing a pair of creasing-wheels of equal radial dimensions, and arranging the creasing-wheels axially separated and rotatable with their centers located on a common axis of rotation, and narrowly spaced to create a singular creasing line in a compressible web material;

providing a circular cutting-wheel with a circular continuous or serrated cutting edge on its periphery at a radius which is less than the radius of the creasing-wheels;

arranging the cutting-wheel rotatable between the creasing-wheels at an axis of rotation which is separate and arranged displaceable from said axis of rotation through the centers of the creasing-wheels, and

controlling the cutting-wheel, through displacement of its axis of rotation, to project the cutting edge radially outside the outer peripheries of the creasing-wheels in simultaneous cutting and creasing operations, and to retract the cutting edge inside the outer peripheries of the creasing-wheels in creasing operations, whereby the cutting- and creasing-wheel assembly is controllable simultaneously to perform cutting and creasing at substantially the same point of contact with the web material.

14. The method of claim 13 , comprising the step of arranging the cutting-wheel movable in a substantially radial direction of the creasing-wheels, and controlling the cutting-wheel in movements substantially perpendicular to the compressible web material.