EP0795353A1 - Document shredder - Google Patents

Abstract

The shredder has cutting rollers (16) with meshing cutting discs (19), and strippers projecting into the spaces between the discs. Modular stripper units (28, 29) with strippers and longitudinal connectors are located separately of the appliance housing, and extend over a considerable part of the cutting roller concerned. Each stripper engages around a cutting roller by more than 180 degrees . Each has pref. two circumferentially opposite acutely angled stripper edges. These act with the base between the cutter discs. Each cutting roller has at least two stripper elements.

Description

The invention relates to a document shredder with a cutting unit, which has cutting rollers with intermeshing cutting disks, in the spaces of which wipers engage, which are connected with wipers that follow one another axially.

Such a document shredder has become known from DE 40 08 654 A1. There are only a small part of the circumference of the cutting rollers wipers made in one piece with the lower housing part and the upper housing part made of plastic. Since it is a cutter with a torsion cut, i.e. With cutting disks that act like scissors with their flanks, the problem of stripping is not very great, since the cut strip twists somewhat in a spiral-like manner and thereby frees itself from the cutting gap.

One-piece scraper webs are also known, which are designed as coherent sheet metal plates into which longitudinal slots are punched, through which the cutting disks protrude through. The webs between them act as wipers (cf. DE 1 289 404 B and DE 1 511 166 B). A similar design is involved in DE 40 03 222 C, where the webs are made of plastic in one piece with the upper or lower part of the housing.

With document shredders that are designed for particle cutting, but also with strip cutters, it is important to wipe off or clear out the grooves between the cutting disks. This can best be done by wipers that are relatively close to the bottom of the grooves between the cutting disks, i.e. on the knife shaft, run and encompass it over a relatively large angle. So far, they have been individually punched out of sheet metal and lined up on the studs connecting the chassis, possibly with spacers between them (see DE 27 49 482 A, DE 37 06 862 A, DE 41 09 467 A and DE 44 36 751 A). . These scrapers work very well, but are very complex to manufacture and assemble.

Task and solution

The object of the invention is to provide a document shredder in which very effective scrapers can be produced and assembled simply and inexpensively.

This object is solved by claim 1. The wipers can thus be separate from the housing, but can even go through them in one piece and coherently over a large part, preferably the entire length of the cutting rollers, and thus be designed in the manner of a disc comb. So they can be made as a single piece from plastic injection molding and can be guided by studs that connect two side bolsters supporting the bearing to a chassis. With appropriate training, you can also replace the stud bolts.

The wipers can encompass the cutting roller by more than 180 ° and have two sharp-edged, in particular acute-angled wiping edges interacting with one another in the circumferential direction and interacting with the shaft sections between the cutting disks. In order to be able to be inserted into the gaps between the cutting disks without any problems, at least two adjacent stripping units can be provided for each cutting roller, which connect and adjoin one another in a suitable manner, preferably the individual strippers with e.g. wedge and groove-shaped engagement elements are centered on each other.

The longitudinal connections can be continuous webs which are curved in the circumferential direction and are designed in the manner of elongated shells partially surrounding the cutting rollers. This gives the stripping unit stability. Continuations of these longitudinal connections can form correspondingly shaped projections which engage in corresponding openings in the cross members, in which the cutting roller bearings are also provided. The wipers are thus attached directly to the crossmember or end shields belonging to the cutting unit chassis. The scraper units can also be used for document shredders that are built without a chassis with a self-supporting housing. When reference is made to document shredders in connection with this invention, this means all shredding devices of this type which can be used for flat materials, that is to say also for packaging materials made of paper, cardboard or other materials, such as, for example, films.

It has proven to be particularly advantageous if the wipers, at least adjacent to the exit side of the shredded writing material, have a section that extends substantially beyond the outer circumference of the cutting disks and a free space behind them, in which the outer delimitation of the wipers preferably extends below the circumference of the cutting disks is reset. The resulting free space enables particles that e.g. are stuck in the tooth gaps of grooved cutting disks after they have passed between the outwardly projecting "horns" which follow the wiping edges, so that they then at the end of the free space when the wipers in turn rise above the circumference of the cutting disks, can be stripped. The scraper not only ensures that the gaps between the cutting disks are cleared, but also that the teeth intended for particle cutting, which are mostly formed by spiral grooves in the cutting disks, and the circumference of the cutting disks, which usually have a V-shaped depression, are kept free .

The wiper unit can also be used to hold a sensor for controlling the cutting unit. The relatively stable wiper element can be protected and positionally secure e.g. a photodiode arrangement for a light barrier controlling the cutting mechanism can be attached.

The cutting unit is blocked by the scraper units together with the crossbeams to form a rigid chassis that absorbs the considerable cutting forces. Particularly preferably, the crossbeams can have receptacles for a pedestal which is preferably made of bar material. The forces can thus be absorbed immediately are without affecting the outer, because of the outer appearance made of optically high-quality plastic housing, which can accordingly be designed specifically for its function and without special wearing properties. Parts of this housing can be supported on the stripping unit, in particular in the region of the insertion slot. This is narrow and relatively wide. The support on the stripping units prevents deformation in this area.

It has been shown that the stripping effect is so good that the scraper effect is so good that the scraper is very precise to the width of the cutting disc and thus of the groove in which they run. This also makes the previous "floating" arrangement of wipers unnecessary. The thickness of the wipers can therefore be considerably less, preferably by 20 to 40%, than that of the cutting disks. This also avoids all problems that could arise due to different tolerances or expansions of the cutting disks and the stripper block. The self-lubricating properties of the plastic injection molding make it possible to adapt the wipers to the cutting roller, in particular the running of the wiper edges close to or on the groove base between the cutting disks, without fear of fretting or excessive frictional resistance.

A document or document shredder is thus created, which can have a cutting mechanism designed as a chassis, in which cutting rollers are mounted so as to be rotatably driven in opposite directions. They are preferably designed as double-sided cutting discs for particle cutting. There are provided as stripper elements extending over the entire length of the cutting rollers, the individual stripper disks of which are combined to form a block via longitudinal connecting elements. Since they reach around the shaft cross-section by more than 180 °, almost 270 °, two stripper elements are connected to each other in the circumferential direction to match each cutting roller. The stripper elements can be made in one piece from plastic injection molding and also serve to connect the two side cheeks of the cutting unit.

These and other features emerge from the claims and also from the description and the drawings, the individual features being realized individually or in groups in the form of sub-combinations in one embodiment of the invention and in other fields and being advantageous and protectable per se Can represent versions for which protection is claimed here.

The division of the application into individual sections and subheadings do not limit the general validity of the statements made under these.

Brief description of the drawings

Fig. 1

eine teilgeschnittene Seitenansicht eines Schneidwerks für einen Schriftgutvernichter mit einer abgenommenen, einen Querträger bildenden Seitenwange,

Fig. 2

einen Querschnitt durch die Schneidwalzen, die Abstreifereinheiten und die Längsträger (Stehbolzen),

Fig. 3

eine Seitenansicht einer Abstreifereinheit,

Fig. 4

die mit den seitlichen Querträgern (Seitenwangen) verbundenen Abstreifereinheiten in montierter Position (ohne Schneidwalzen und Getriebe),

Fig. 5

die vier zu einem Schneidwerk gehörenden Abstreifereinheiten in Frontansicht und

Fig. 6

ein Detail (in Richtung des Pfeils VI in Fig. 2 gesehen).

An embodiment of the invention is shown in the drawings and is explained in more detail below. The drawings show:

Fig. 1

2 shows a partially sectioned side view of a cutting unit for a document shredder with a removed side cheek forming a cross member,

Fig. 2

a cross section through the cutting rollers, the stripper units and the longitudinal beams (stud bolts),

Fig. 3

a side view of a wiper unit,

Fig. 4

the scraper units connected to the lateral cross members (side cheeks) in the assembled position (without cutting rollers and gears),

Fig. 5

the four scraper units belonging to a cutting unit in front view and

Fig. 6

a detail (seen in the direction of arrow VI in Fig. 2).

Description of the embodiment

The centerpiece of a document shredder 11 is the cutting unit 12, which is designed in a chassis construction. It contains two side walls or cross members 14, 15 (FIG. 4), of which the cross member 15 simultaneously contains a gear box 17 in which gear wheels, not shown in FIG. 4, for reducing the drive speed originating from an electric motor, not shown, to the working speed of the Cutting rollers 16 (Fig. 1 and 2) provide.

The cutting rollers 16 are made in one piece from steel and, starting from a continuous shaft cross section 18, have outwardly projecting cutting disks 19 with grooves or tooth gaps 21 which are provided therein and lead in the direction of rotation 20, which accordingly form a forward-facing cutting tooth 22. Because of the Details of the cutting disc formation and its effect are referred to DE 22 47 901 B.

Grooves 23 are formed circumferentially between the individual cutting disks, the width of which is such that they cooperate with a suitable fit for cutting between the peripheral edges of the cutting disks 19 with the corresponding cutting disk of the other cutting roller. It can be seen in particular from FIG. 2 that the cutting rollers engage in one another in such a way that each cutting roller cooperates with its circumference 24 at a relatively short distance from the groove base 25 of the groove 23 of the opposite cutting roller. The cutting disks are dimensioned according to the desired dimensions of the particles, i.e. For example, 4 mm wide and have some, in the present example 4 grooves or tooth gaps 21 on the circumference. These, in cooperation with the circumference 24 of the opposite cutting disc, ensure that the strips cut by the peripheral edges of the cutting discs are torn apart or cut into individual particles. The cutting discs are synchronized, i.e. driven at the same speed, in opposite directions in the direction of rotation 20, so that they grip the material in the area of the inlet gap 26 and release the particles at the material outlet 27.

The cutting rollers 16 are associated with stripper units 30 which, for each cutting roller 16, consist of two separately manufactured stripper elements 28, 29. They are made as one piece from plastic injection molding in the manner of a disc comb. Their wipers 31, which are designed as flat segments or disks, are connected to one another by a longitudinal connection 32 running over the entire length of the wiper. This has the shape of an annular shell segment surrounding the cutting disk circumference 24 at a distance, which ensures good rigidity with low material expenditure worries. In extension of this longitudinal connecting web 32, connecting elements 33 protrude on both sides, which are inserted into corresponding crescent-shaped cutouts 34 on the two cross members 14, 15 (FIG. 4). By means of a shoulder 35 designed as a shoulder (FIG. 3), they also fix the cross members 14, 15 in their spacing. By means of appropriate connecting means, for example clamping connecting means or the like, the connecting elements in the cross member can also be fixed against tension.

In the present case, however, the longitudinal connection between the two cross members is ensured by four longitudinal members 36 which rigidly connect the cross members to one another at the predetermined distance in the manner of stud bolts. In Fig. 1 it can be seen that this is done by screws screwed into threaded holes 37 of the longitudinal beam 36, which are screwed in from the outside of the cross member.

The shape of the wipers 31 can be seen in particular from FIGS. 2 and 5, to which express reference is made because of the shape. Although two stripper elements 28 and 29 are required for each document shredder, the entry-side elements 28 and the exit-side elements 29 can be the same for both sides. They are only assembled in mirror image to each other.

The two wiper elements 28 on the inlet side enclose the relatively narrow inlet gap 26 between their mutually facing edges 39. Adjacent to this there is a sharp, acute-angled scraping edge or cutting edge 40 on the groove base 25, which is followed by an arc section 41 adapted to the shaft cross section 18. On the part of the cutting rollers facing away from the cutting gap 42, where the overlapping cutting disks 16 work together, is a Connecting section 43, which is shown in the example shown as a V-shaped rib or spring 43 (Fig. 6).

It works together with a corresponding V-shaped recess 44 on the wipers 31 of the outlet-side wiper elements 29 for the mutual fixing and centering of each individual wiper 31 on that of the adjacent wiper element.

The wipers 31 of the wiping element 29 near the outlet likewise have a sharp-edged, wiping blade 40 and an edge 39 delimiting the outlet gap 27 thereafter is relatively narrow. Following the edge 39 there is a horn 45 projecting far beyond the circumference 24 of the cutting disks, on which stripped particles are pushed along by the cutting disks until they fall downward from the cutting gap area.

Following this horn, a free space 46 is created in that the outer edge of the scraper is recessed up to within the circumference 24 of the cutting disk 19. Then the outer circumference goes back to the large distance from the center that the horn had.

In the case of both stripper elements 28, 29, the longitudinal connections 32 are arranged next to one another in such a way that, connected via the V connection 43, 44, they enclose approximately a third circle. The wipers assembled from the two elements 28, 29 enclose the cutting roller on the groove base 25 by more than 180 °, preferably close to 270 °.

Both wiper elements have in their wipers approximately semi- to third-circle-shaped recesses 47, in which the longitudinal members 36 lie, which thus fix and guide the wiper elements 28, 29.

The individual wipers 31 are relatively thin compared to the thickness of the cutting disc. 3 and 4 show that each cutting roller and thus also each stripper element has about thirty scrapers lying next to one another, which are arranged at a pitch of, for example, 8 mm from one another, which results in a cutting wheel thickness of somewhat less than 4 mm. In contrast, the wipers themselves are only approx.2.6 mm thick, i.e. about 35% narrower than the cutting disks or the circumferential groove 23 formed between them. Despite the resulting large distances, the wiping result is good because the wiper blades 40 can run directly on the groove base 25 and thus ensure good wiping.

3 and 4 also show that the upper stripping elements 28, which are primarily shown in these drawings, have in their center a receptacle 48 for the sensor 49 of a cutting unit motor control, for example a light barrier. It can be snapped in there and is protected and directly at the entry gap 26.

Fig. 1 shows that a housing, not shown in detail, can be supported with the housing sections 50, 51 (shown in dash-dotted lines) delimiting the entry gap 26 on the outer boundary of the edge 39, so as to ensure precise alignment of the narrow and wide insertion slot 26 to care.

1 and 4 also show that receptacles 52 for a base 54 are formed from the end of the cross member remote from the cutting rollers. This is designed as a downwardly extending bracket made of rod material, and its upper ends are received in the receptacle 52 in the form of a cylindrical receptacle. So that the chassis of the cutting unit 12 stands directly on the feet, and the forces acting on the document shredder 11, which mainly result from the cutting unit, are absorbed directly by the base.

function

The document shredder 11 operates as follows: Document or other flat material is brought into the area of the cutting gap 42 through the entry gap 26. After switching on the device, a signal is generated by the sensor 49 which puts the drive (motor and transmission), not shown, into operation in the forward gear. The cutting rollers rotate in opposite directions in the direction of rotation 20 and take the writing material into the cutting gap. Corresponding strips are cut between the cutting edges of the cutting disks in the width of the cutting disks and, at the same time, separated into particles by the interaction of the cutting disks with the transverse grooves 23. These fall down from the exit gap 27 into a container arranged under the document shredder. If particles stick in the grooves 23 or on the groove base 25, they are stripped off by the scrapers 31 and in particular by the scraper cutting edge or edge 40, due to the almost tangential arrangement of the edges 39 also transported outwards as a result of the rotation of the cutting disc and thrown off downwards . Should particles stick to the circumference of the cutting disk or stick in particular in the grooves 21 of the cutting disks Taken between the horns 45, they can expand to the side in the area of the adjoining free spaces 46 and are then held back by the subsequent edge 53 of the wipers 31 and thrown downwards.

Should a stall occur, the cutting mechanism is reversed in the direction of rotation either by automatic control or manually and thus conveys the "lump" that has formed back upwards. The stripping edges 40 lying on the entry side 26 act in order to prevent particles of writing material from being conveyed around the cutting rollers in this reverse direction of rotation.

Claims (10)

Document shredder with a cutting unit (12) which has cutting rollers (16) with interlocking cutting disks (19), in the interstices (23) of which scrapers (31) which are connected with axially successive scrapers engage, characterized in that the scrapers (31) on at least one stripper unit (28, 29), which is separate from the housing and extends over a substantial part of the axial extent of the respective cutting roller (16) and is integral with the strippers (31) and connects them. Document shredder according to claim 1, characterized in that the wipers (31) encompass the respective cutting roller (16) by more than 180 ° and preferably two sharp-edged, in particular acute-angled, circumferentially opposite, with the groove base (25) between the cutting disks ( 19) has interacting scraper edges (40). Document shredder according to claim 1 or 2, characterized in that at least two per cutting roller (19) Scraper elements (28, 29) are provided which connect to one another in the circumferential direction, the individual scraper elements (31) of the elements preferably being centered on one another, for example with wedge-shaped and groove-shaped engagement elements 43, 44. Document shredder according to one of the preceding claims, characterized in that the longitudinal connections (32) are webs which are curved in the circumferential direction. Document shredder according to one of the preceding claims, characterized in that the wipers (31) at least adjacent to the outlet side (27) for the shredded documents, then on wiping edges (40), a section (projecting substantially beyond the outer circumference (24) of the cutting disks (19). Horn 45) and behind it a free space (46) in which the outer boundary of the wipers (31) is preferably set back below the circumference of the cutting disc (24). Document shredder according to one of the preceding claims, characterized in that the stripping elements have longitudinally extending recesses (47) for partial reception and support on longitudinal members (36) of the cutting mechanism chassis, which are preferably designed as stud bolts and / or the stripping elements (28, 29) are preferably have projections (33) designed as a continuation of the longitudinal connections (32), which engage in crossbeams (14, 15) receiving cutting roller bearings and are optionally fixed there as longitudinalbeams connecting the crossbeams, in particular one of the crossbeams (15) having a gearbox (17) forms, and / or the stripper elements (28, 29) and possibly the cross member (14, 15) one-piece plastic injection molded parts are, the cross members (14, 15) preferably having receptacles for a stand (54) which is preferably made of bar material. Document shredder according to one of the preceding claims, characterized in that at least one stripper element (28, 29) on the material entry side (26) has a receptacle (48) for a sensor (49) for controlling the cutting unit. Document shredder according to one of the preceding claims, characterized in that the cutting disks (19) are designed for particle cutting, preferably by grooves (21) in the circumference of the cutting disk (24). Document shredder according to one of the preceding claims, characterized in that sections (50, 51) of a housing surrounding the cutting mechanism (12) are supported on at least one of the stripper elements (28, 29). Document shredder according to one of the preceding claims, characterized in that the wipers (31) between them delimit a narrow material insertion gap (26) and a substantially wider, preferably wedge-shaped opening gap (27), and, if appropriate, the thickness of the wipers (31) considerably , preferably 20 to 40%, is less than that of the cutting disks (19).

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