A machine is described for perforating webs of material, such as toilet paper. The machine includes a cylinder (17) mounted on the frame of the machine and around which cylinder the web is carried as the web passes through the machine. The cylinder has a plurality of blades, one edge of each extending beyond the surface of the cylinder and parallel to the axis of the cylinder. A support (21) for a cooperating blade (33) is pivotally mounted on the machine in a manner which permits the cooperating blade (33) to move toward and away from the blades in the cylinder (17). The cooperating blade (33) extends at an angle to the axis of the cylinder and consists of a plurality of segments, each of which is supported in a block (25) which fits into seats in the support. The seats extend in a line parallel to the cylinder axis.

A comminuting striker and retainer for mounting to a striker mounting face of a comminuting rotor by bolts in which the striker is located by a projection on the retainer which can be disengaged from the striker by loosening the bolts without removing the bolts and retainer from the rotor, the striker having a slot which then allows the striker to be slid laterally from the bolts for removal from the rotor.

A transverse cutter for a running web of paper or the like has two rotary drum-shaped holders disposed opposite each other at the opposite sides of the path for the web. Each holder carries at least one knife with an elongated cutting edge extending transversely of the path of movement of the web, and each knife of one holder cooperates with a knife of the other holder to sever the web once during each revolution of the holders. One of the knives is adjustable with reference to the respective holder so that its cutting edge can be shifted relative to the cooperating cutting edge of the other knife. The adjusting mechanism for the adjustable knife includes a row of closely adjacent wedge-like retainers which are recessed into the peripheral surface of the respective holder and are movable radially of such holder by threaded fasteners which can move the associated retainers radially inwardly against the opposition of dished springs in the respective holder. Each retainer has a projection which engages one side of the adjustable knife midway between the cutting edge and the innermost portion of such side. The other side of the adjustable knife bears against a second row of wedge-like retainers which are recessed into the respective holder and have projections bearing against the innermost portion of the other side of the adjustable knife. Such mounting allows for at least some elastic flexing of the adjustable knife.

The present invention relates to a device for retaining knife blades for cutting, perforation or other treatment of a running web, preferably a paper web. The web runs between a rotatable knife-retaining cylinder and a counter pressure cylinder, whereby the knife blade may be wedged up by a wedge device by being brought into the slot by the counter pressure cylinder. In order to permit effective wedging up of knife blades in exact positions in the slot, even when the blades have dimensions which differ from knife blades of the certain defined dimension, the wedge device comprises and/or cooperates with at least one spring disposed beside the wedge device in the slot, upon insertion of a knife blade into the slot for wedging up thereof by the counter pressure cylinder. The spring is compressible to a dimension which lies within such an interval that it permits insertion of those knife blades into the slot, the dimensions of which differ from the certain, defined dimension and lie within such a certain, defined range of tolerance including the defined dimension. The spring, when compressed to a dimension within the interval, has such a spring force that knife blades having dimensions within the range of tolerance are retained in the slot.

In a mounting arrangement for mounting a hard metal cutting blade in a cutting head in a mounting groove of the cutting head in an adjustable radial position, wherein the cutting blade is disposed on a support plate and engaged by a clamping bolt. The support plate includes a cut-out in which a profile plate having a tooth-like structure is received and the cutting blade includes a complimentary tooth-profile structure in engagement with the profile structure of the profile plate and an elastic insert is disposed in the cutout behind the profile plate for elastically biasing the profile structure of the profile plate into play-free engagement with the profile structure of the cutting blade when forced into engagement with one another by the clamping bolt and the clamping member.