DE1216327B - Device for longitudinal cutting of sheets in the delivery of printing machines - Google Patents

Description

Device for longitudinal cutting of sheets in the delivery of printing machines The invention relates to a device for slitting sheets in the Boom of printing machines by means of a rotating circular knife and a fixed one Counter knife.

For slitting sheets on printing machines, it is known to use the feed drum is a rotating circular knife in front of the entry of the sheets into the printing machines to arrange that works with a circular knife above. In order to however, only an imprecise cut can be achieved. When arranging the cutting knife The cutting ring on the boom drum must in turn be interrupted in order to allow it to run in of the gripper systems to allow the drum so that part of the sheet is not can be cut. In the case of cutting devices in the boom, in turn, where is cut with its own cutting drum, there is a risk of smearing the arc. In another known cutting device in the boom you have the The gripper shaft is set higher on the chain so that the counter knife is below it to be able to accommodate. However, the deflection of the chain causes an uneven run. It is also known to use a rotating circular knife for longitudinal cutting of sheets to be used together with a two-part fixed counter knife. The latter is only arranged on one side of the circular knife and also has a considerable length. Another slitter will be bowl-shaped Knife pairs subjected to an axially parallel pressure for the purpose of sharpening the knives.

Such a design is, as already mentioned, with chain booms not usable due to the large space requirement. With a paper cutter, in which a rotating circular knife in a slot of a fixed counter knife engages, the counter knife is resiliently mounted, but there is no pressing in axial direction provided, so that no flawless because of the width of the slot Cut is possible.

To remedy the disadvantages mentioned, it is proposed according to the invention that for longitudinal cutting of sheets in the delivery using a rotating circular knife as a fixed counter knife two resilient on both sides of the circular knife the cutting edges to use cutting tips that are pressed against the vertical are offset to the knife axis in the direction of the sheet infeed. By this measure it is possible to do a flawlessly without redirecting the chain in the small space available to accommodate acting cutting device. Through the design of the cutting tips at the same time, the cutting force of the knife is created by itself again and again from carbide renewed.

An exemplary embodiment of the invention is shown in the drawing. FIG. 1 shows a side view, FIG. 2 shows a section along line II-II of F i g. 1, Fig. 3 is a plan view in the direction of arrow A in FIG. 1., The The cutting device essentially consists of a circular undercutter 1 and this partially enclosing two-part holder 2.2 ', which one Has slot 3 into which the sheet 4 is inserted. In the bracket 2 are in the area of the cutting knife on both sides of the same cutting tip 5 Carbide provided, which serve as a fixed counter knife. The by leaf springs 6 pressed plates are slightly beveled on the contact surfaces with the knife and are opposite the vertical of the axis of the knife in the direction of the sheet entry something shifted. The two parts of the holder 2, 2 'are behind the circular knife 1 connected to one another by a knife 1® that moves the sheet halves apart.

Outside the circular knife 1 are approximately the same on both sides Diameter having suction drums 7 and S are provided, which are used to guide the serve cut bow. The attachment of the knife as well as the drive of the same can be done in a manner known per se and is therefore not detailed described. From FIG. 1 it can be seen that the entire cutting device can be arranged at a small distance below the rotating boom chain 9.

Claims (1)

Claims: 1. Device for longitudinal cutting of sheets in the delivery of printing machines by means of a rotating circular undercutter and a fixed counter knife, d u r c h g e - indicates that on both sides the circular knife (1) resiliently pressed against the cutting edges (5) are provided as counter knives, which are opposite to the perpendicular to the knife axis in The direction of the sheet entry are offset. "2. Device according to claim 1, characterized characterized in that the platelets (5) are made of hard metal in a known manner and their contact surfaces with the circular knife (1) are beveled. Into consideration Drawn publications: German Patent Nos. 104 484, 111218, 1029 833; British Patent No. 699,381.