Cutting unit

A cutting unit comprising:

• a stationary frame;
• an upper cutting drum having at least one cutting knife disposed on an outer cylindrical surface of the upper cutting drum and a centre axis of rotation, wherein the at least one cutting knife is arranged on the outer cylindrical surface of the cutting drum in a cutting zone having an axial extension on the cutting drum;
• a hollow lower anvil drum having an outer cylindrical surface and a centre axis of rotation, wherein the cutting drum and the anvil drum are arranged one over the other for receiving cutting web material fed between them, the centre axis of rotation of the cutting drum being parallel with the centre axis of rotation of the anvil drum, the cutting drum being centered on an arbour rotatably supported in the stationary frame, the arbour and the cutting drum being rotatable around the centre axis of rotation of the cutting drum, and wherein the anvil drum is rotatable around the centre axis of rotation of the lower anvil drum and movable towards and away from the cutting drum;
• a carrier movable towards and away from the cutting drum, wherein the carrier includes a first pair of contact rollers comprising a first left contact roller and a first right contact roller located at a near end of the carrier, and the carrier includes a second pair of contact rollers comprising a second left contact roller and a second right contact roller located at a far end of the carrier, each contact roller of the first and second pairs of contact rollers having an outer cylindrical surface and being rotatable around a respective centre axis, each centre axis of each contact roller of the first and second pairs of contact rollers extending parallel with the centre axes of rotation of the cutting drum and the anvil drum, the anvil drum being arbourless and shaftless such that a near end and a far end of the anvil drum are not supported by the frame, the outer cylindrical surface of the anvil drum freely resting only on the outer cylindrical surfaces of the first and second pairs of contact rollers, wherein the first left contact roller and the second left contact roller are situated on a left side of a central vertical plane of the anvil drum and the first right contact roller and the second right contact roller are situated entirely on a right side of the central vertical plane of the anvil drum for providing vertical and transversal support of the anvil drum by the pairs of contact rollers only, such that the anvil drum is rotatable about the centre axis of rotation of the anvil drum, said center axis of rotation of the anvil drum being parallel to the centre axis of each contact roller of the first and second pairs of contact rollers such that, in a transverse vertical plane, the centre axis of each contact roller of the first and second pairs of contact rollers is oriented relative to the centre axis of the anvil drum in a v-shape formation, with the centre axis of the anvil drum located at a vertex of the v-shape and the centre axes of the contact rollers of the first and second pairs of contact rollers located at tips of the v-shape distal from the vertex, where a vertex angle of the v-shape is at least 45′ and at most 120′;
• a safety device comprising a bar which extends through an entire length of the hollow lower anvil drum without contacting an interior wall of the hollow lower anvil drum, wherein the bar extends past each of the near and far ends of the hollow lower anvil drum and a first end of the bar is secured by a first clamp and a second end of the bar is secured by a second clamp, wherein the first and second clamps are attached onto the carrier;
• and
• a pressing device connected to the carrier and arranged to move and press the carrier and the anvil drum carried by the carrier towards and against the cutting drum for providing cutting pressure between the cutting drum and the anvil drum, wherein the anvil drum is hollow and contains the bar of the safety device to prevent the anvil drum from being ejected if contact is lost between the first and second pairs of contact rollers and the anvil drum.

A cutting unit comprising:

• a stationary frame;
• an upper cutting drum having at least one cutting knife disposed on an outer cylindrical surface of the upper cutting drum and a centre axis of rotation, wherein the at least one cutting knife is arranged on the outer cylindrical surface of the cutting drum in a cutting zone having an axial extension on the cutting drum;
• a hollow lower anvil drum having an outer cylindrical surface and a centre axis of rotation, wherein the cutting drum and the anvil drum are arranged one over the other for receiving cutting web material fed between them, the centre axis of rotation of the cutting drum being parallel with the centre axis of rotation of the anvil drum, the cutting drum being centered on an arbour rotatably supported in the stationary frame, the arbour and the cutting drum being rotatable around the centre axis of rotation of the cutting drum, and wherein the anvil drum is rotatable around the centre axis of rotation of the lower anvil drum and movable towards and away from the cutting drum;
• a carrier movable towards and away from the cutting drum, wherein the carrier includes a first pair of contact rollers comprising a first left contact roller and a first right contact roller located at a near end of the carrier, and the carrier includes a second pair of contact rollers comprising a second left contact roller and a second right contact roller located at a far end of the carrier, each contact roller of the first and second pairs of contact rollers having an outer cylindrical surface and being rotatable around a respective centre axis, each respective centre axis of the first and second pairs of contact rollers extending parallel with the centre axes of rotation of the cutting drum and the anvil drum, the anvil drum being arbourless and shaftless such that a near end and a far end of the anvil drum are not supported by the frame, the outer cylindrical surface of the anvil drum freely resting only on the outer cylindrical surfaces of the first and second pairs of contact rollers, wherein the first left contact roller and the second left contact roller are situated on a left side of a central vertical plane of the anvil drum for providing vertical and transversal support of the anvil drum by the pairs of contact rollers only, such that the anvil drum is rotatable about the centre axis of rotation of the anvil drum, said centre axis of rotation of the anvil drum being parallel to the centre axis of each contact roller of the first and second pairs of contact rollers such that, in a transverse vertical plane, the centre axis of each contact roller of the first and second pairs of contact rollers is oriented relative to the centre axis of the anvil drum in a v-shape formation, with the centre axis of the anvil drum located at a vertex of the v-shape and the centre axes of the contact rollers of the first and second pairs of contact rollers located at tips of the v-shape distal from the vertex, where a vertex angle of the v-shape is at least 45° and at most 120°;
• a safety device comprising a bar which extends through an entire length of the hollow lower anvil drum without contacting an interior wall of the hollow lower anvil drum, wherein the bar extends past each of the near and far ends of the hollow lower anvil drum and a first end of the bar is secured by a first clamp and a second end of the bar is secured by a second clamp, wherein the first and second clamps are attached onto the carrier;
• and
• a pressing device connected to the carrier and arranged to move and press the carrier and the anvil drum carried by the carrier towards and against the cutting drum for providing cutting pressure between the cutting drum and the anvil drum.