DE2247901A1 - METHOD AND DEVICE FOR DESTRUCTION OF FILES - Google Patents

Description

Dr.-Ing. G. Riebling

Patent attorney

699 Lindeu-B., Rwnerle 10 2247901

Tthho WMi'6917 _r TIm OS 4374

Sch 172

Precision engineering Schleicher & Go. 77s Markdorf / Lake Constance

Process and device for shredding files

The invention relates to a method and a device for shredding files.

The incineration-free destruction of files has so far been carried out in such a way that the sheets of paper to be destroyed cut into long, narrow strips. The document shredding machines used for this point two knife rollers, whose knife disks are lined up equiaxially with little play interlock. In another design, the knives are arranged parallel to the cutting roller.

Such document shredding machines produce relatively long strips of paper that are loose successively a ball of paper with a multiple Form the volume of the cut sheet of paper. These paper strips must therefore in order to make them more economical Way, e.g. as part of garbage collection, initially by baling or similar additional machines to the smallest possible volume to be brought.

The destruction of files by the formation of stripes also has the disadvantage that individual strips of paper are detached Whole lines of the cut documents can be read from the material to be cut.

The invention is therefore based on the idea of not only cutting the written material into narrow longitudinal strips, but to tear or cut these longitudinal strips several times in the transverse direction. The cut material should therefore consist of a large number of non-contiguous short longitudinal strips.

The idea of subsequently dividing the long paper strips several times in the transverse direction is technically feasible cannot be implemented in a simple manner because the strips have too little resistance to the cutting or tearing tools Offer.

According to the invention, it is therefore proposed that the documents to be divided be divided into longitudinal strips before being divided to be provided with short cross-sections corresponding at least to the width of the longitudinal strips.

These two cutting or tearing processes can be carried out in one Document shredding machine can be carried out in one operation that one on the circumference of the knife disks

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provides tear edges running parallel to the knife axis roller. ' ■ ■■

The hooking edges of a longitudinal groove cut into the circumference of the cutter disks , which preferably runs helically, preferably serve as tear edges.

The groove profile expediently has a nose pointing in the direction of rotation of the knife roller, the nose angle should be less than 90 ° »but preferably above 75 °.

The knife rollers can be assembled from individual parts in any way. That will be useful Roll profile, however, worked out of a tube with a correspondingly thick wall thickness.

The storage of the knife rollers with a relatively large diameter is expediently carried out in such a way that one arranges the bearings axially shifted from each other in the bearing plate of the document shredding machine *

The invention is explained below using exemplary embodiments with reference to the accompanying drawings will.

Show it:

1 shows a plan view of two interlocking knife rollers of a document shredding machine the invention;

FIG. 2 shows a section through the device according to FIG. 1 along the line H-II;

Fig. 3 is a sectional view of a partially cut sheet of paper and

FIGS. 4 and 5 show two explanatory sketches of how it came about of the sectional view according to FIG. 3.

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22A7901

In Fig. 1, 1 and 2 are the two axes of rotation of the two knife rollers shown in phantom 3, 4- designated. Both rollers 3 »4 · are axially offset stored in a housing plate 5 of the document shredding machine, otherwise not shown in detail. One of the Knife rollers 3, 4- is driven by a motor, not shown, while the other roller by means of Pinion is taken.

Both knife rollers consist of a plurality of sharp-edged ones Cutting disks 6 in the form of flat cylinders which are strung together at a distance such that the The cutter disks of one roller engage with the cutter disks of the other roller with little play

The knife rollers are expediently manufactured by appropriate milling of suitable tubes Diameter and suitable wall thickness.

While the cutter disks previously had the geometric shape of flat circular cylinders, their outer surfaces are now provided by milling grooves with additional tear edges that are transverse to the longitudinal direction of the paper strip get lost. The groove profile is expediently chosen in such a way that in the direction of rotation of the cutter disks pointing noses arise, the edges 7 of which form the tear edges. The nasal angles should be less than 90 ° and preferably greater than 75. If the nose angle is more than 90 °, the cross-cutting edge would be blunt step into the paper and would have no cutting effect. Too acute a corner of the nose would increase the risk of breakage that could be triggered by nails or staples getting between the knife rollers.

A nose angle smaller than 90 ° can be achieved by a corresponding undercut of the groove or an inclined one

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Course of the groove can be achieved.-But it can also be how is indicated by dashed lines in FIG. 5, the surface adjacent to the edge is trough-shaped on the circumference of the knife roller be taken away. · *

Due to the helical arrangement of the tear edges 7 or the grooves that produce them, the tear edges become adjacent Knife disks 6 offset from one another in the circumferential direction and therefore come into effect one after the other. ! As a result, the drive energy to be applied for the tearing processes is uniform over the circumference of the knife roller distributed. In this case, the document shredding machine can use a lower drive power will see and be made of a lighter design.

The working principle of the invention will now be explained with reference to FIGS. 3-5. - In the area of the groove 10, the longitudinal cutting is interrupted. This area is indicated on the sheet of paper in FIG. 3 by the reference symbol 13 designated. When the edge 13 enters between the two opposing cutter discs, a transverse view takes place (denoted by 14 in FIG. 3). The transverse cutting or tearing precedes the longitudinal cutting. When turning the knife roller further the longitudinal cutting begins at the edges of the transverse crack 14 and is also continued in the area 13, so that Ultimately, the result is uninterrupted longitudinal cuts. 3 shows this progression of the longitudinal sections left to right.

The depth of the grooves is greater than or equal to the width of the knife. An uncut, transverse strip of paper is pushed through the smooth knife surface into the groove pressed in, so that within the groove from point A to the bottom of the groove over the edge 17 a strong Tension takes place. Before the penetration of the cross-cutting

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Edge 17 in the paper is thus reached a pretensioned state that the penetration of the bite edge and making it easier to tear through.

The process of transverse tearing is facilitated by a further groove 20, which runs in the direction of rotation of the knife rollers in front of which the tear edge 7 contained anger 10 is arranged. It has been shown that such a draw-in groove achieves a better effect than a knurled one or knurled surface of the cutting discs.

The invention creates a multitude of incoherent short vertical stripes. These particles stick together in close packing and only form a small volume.

This new type of file distribution has the further advantage that the paper items after inoculation with putrefactive bacteria can be exposed to a very rapid putrefaction process and can then be used as humus are. In addition, the proposed way of distributing files meets the requirements of confidentiality in an optimal way. Compared to the process, the paper strips, in order to completely exclude legibility, very much To cut narrowly, i.e. less than 1 mm wide, a significantly lower cutting energy is required.

It is preferably proposed to choose a format of 4 × 20 mm or 4 × 15 mm for the paper particles.

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Claims (1)

Claims Process for the destruction of files by cutting sheets of paper into small particles including the Cutting the sheet into narrow longitudinal strips, characterized in that the to be cut Before dividing the sheet into 'longitudinal strips with short, at least the width of the longitudinal strips Provides cross-sections. Document shredding machine for carrying out the method according to claim 1 with two knife rollers, whose Cutting disks are lined up in such a way that the cutting disks of a roller with little Play in the cutter disks of the other roller, characterized in that the cutter disks (6) are provided with tear edges (7) running parallel to the knife roller axis (1, 2). Device according to claim 2, characterized in that that the tear edges (7) cut through the trailing edges of a knife roller surface Groove (10) are formed. Device according to claim 5> characterized in that that the NUt (10) helically around the knife roller axis (1, 2) runs. Device according to claim 3 »or 4, characterized in that that the groove profile one in the direction of rotation the knife roller pointing nose (7), wherein the nose angle is less than 90 ° and preferably is greater than 75 °. 409815/0096 6. Device according to one of the preceding claims, characterized in that the knife rollers (3 »4 ·) are made from pipe parts. 7. Device according to one of the preceding claims, characterized in that the knife rollers (3, 4-) are mounted in axially offset bearings. . 40981 5/0096