EP0419919B2 - Shredder device for refuse - Google Patents

Abstract

A shredder device for refuse, such as wood, paper or plastic, has a rotor (3) with circumferential ribs (10). Each circumferential rib is interrupted by at least one pocket (14). Arranged in the latter is a tool holder with the tool (19). The tool (19) has a profile which protrudes radially over the rib profile to approximately the same degree. This produces a shredder device in which load peaks and jamming can be largely avoided. <IMAGE>

Description

The invention relates to a shredding device for waste such as wood, paper or plastics, according to the preamble of claim 1.

In a known shredding device of this type (FR-A-24 51 777) the peripheral ribs have a rectangular cross section. The pocket consists of a radial bore into which a cylindrical extension of a tool holder is inserted. The tool holder is fastened to the rotor by means of a weld seam which takes place between an extension section adjoining the extension and the cylindrical rib surface. The tool holder carries at its radially outer end a cutting tool which is supported on a step of the tool holder and welded there. The tool is positioned radially outwards, which leads to high loads on the tool and tool holder and promotes jamming.

In another shredding device known on the market, a tool holder is welded into each circumferential groove which is formed between two adjacent circumferential ribs. The circumferential ribs and thus also the circumferential grooves have a V-shaped profile in which the side surfaces form an angle of 90 ° between them. The tools are square. Such devices are mainly used for the shredding of wood waste from sawmills, carpentry, joinery and furniture factories, but can also be used for shredding paper waste, computer paper, packaging materials such as cardboard boxes, pallets, wooden boxes and plastics etc. With larger devices, demolition wood, tree roots and branches, cemetery waste etc. are crushed.

In devices of this type, the waste is fed unsorted into a filling shaft. A horizontally reciprocating moving floor feeds the material to be shredded to the rotor. Every time the push floor returns from its front end position near the rotor, the material slips due to its own weight and is presented to the rotor in a disordered manner. It has been shown here that high peak loads of the rotor torque occur. In addition, the material can easily get caught between the rotor and counter knife.

Furthermore, a device for producing wood chips is known (DE-A-14 53 328), in which circumferential ribs with a V-shaped profile have a radially adjustable tool following a chip removal groove and are held in place by a clamping device. A counter knife is not provided. Rather, the wood to be shredded is fed parallel to the axis of rotation of a conical rotor or with an inclination to the axis of rotation of a cylindrical rotor.

Also known is a device for destroying microfilms and the like (DE 26 41 370 C2), in which the rotor is provided with a circumferential rib having an approximately V-shaped profile. Numerous axially extending transverse grooves result in a group of movable cutting edges which have a meandering or zigzag-shaped fine structure and which interact with a counter knife adapted to their profile. If the movable cutting edges wear out, the entire rotor must be refurbished or replaced.

In the case of milling cutters, it is known (DE 10 99 315 B) to provide a rotor with grooves running in the axial direction and to arrange toothed racks which can be displaced axially relative to one another in these grooves, the teeth of which are supported on elevations of the rotor arranged one behind the other in the circumferential direction. In another known roller milling cutter (DE 593 531 C), the elevations on which the toothed strips are supported lie on a helical line and the toothed strips are axially fixedly mounted thereon.

The invention is based on the object of specifying a comminution device of the type described in the introduction in which the risk of stress peaks and jamming is considerably reduced.

This object is achieved by the features of claim 1.

While in the known case wedge-shaped pieces of material of quite different sizes are cut off, according to the invention there is a constant maximum depth of cut over the entire working width, which is equal to the radial protrusion of the tools over the associated rib profile. The uniform removal of material for each rotor revolution means that the material can be fed in at a corresponding speed. A high throughput is achieved by choosing an appropriate feed. Since the material is machined evenly, there are low coefficients of friction between the rotor body and the material to be shredded, less heating of the rotor, so there is no risk of fire and corresponding energy savings. The uniform depth of cut also limits the penetration of the tools into the material to be shredded. This reduces the load peaks (torque peaks) of the rotor drive, which enables the use of motors with lower drive power and thus energy savings.

The gap that must be present between the counter knife and the circumferential ribs because of the protruding tools is comparatively narrow. Therefore, the risk that the waste jams in this gap is significantly reduced.

Another advantage is that relatively large robust tools can be used for a given cross-section of the circumferential ribs, which are accordingly insensitive to foreign bodies such as metals, stones, etc. Such large tools can also be used if only a low drive power is available and / or fine chip granulate is required because the radial protrusion of the tool over the rib profile is selected accordingly can be. For reasons of rationalization, it is recommended to use a size of the tool and the associated tool holder and to adapt it to different chip sizes or drive powers using rotors with differently sized cross sections of the circumferential ribs.

A V-shaped profile of the tool and peripheral rib is easy to manufacture. If the side surfaces of the V-profile are at right angles to each other, the greatest stability of the peripheral rib and tools results. The square tools have the advantage that sharp cutting corners can be brought into the working position by turning 90 °. This is particularly true because the three non-radially outer cutting corners are largely protected in the pocket and therefore do not become dull during operation.

The corner dimension of the tool measured in the direction of the rotor axis is larger than the width of the circumferential ribs. The tool parts projecting beyond the circumferential rib in the axial direction overlap with the rotational path of the tool of the adjacent circumferential rib, so that the material is certainly completely shredded over the working width.

It is also advantageous that the flat boundary surfaces of the prism form extensions of the side surfaces of the adjacent circumferential ribs in the region of the tool. This makes it possible to use tools that also have a V-shaped profile in the radially inner part, even if they have a larger corner dimension than the width of the circumferential ribs.

Furthermore, the tool holder should have two flat contact surfaces adapted to the prism. This results in particularly good support for the heavily loaded tool holder.

It is even cheaper if the tool also has cutting edges on both sides. Then even an eight-sided use of the tool is possible.

It is particularly advantageous to ensure that the tool only projects radially beyond the rib profile to such an extent that the correspondingly adapted serrations of the counter knife overlap the rib profile in the radial direction. This overlap practically eliminates jamming of materials and largely prevents long wood fibers from being torn out.

Furthermore, the pockets should be distributed spirally over the rotor. This results in an even Drive load.

• Fig. 1 einen schematischen Längsschnitt durch eine erfindungsgemäße Vorrichtung,
• Fig. 2 eine Seitenansicht, teilweise m Längsschnitt, des Rotors einer erfindungsgemäßen Vorrichtung,
• Fig. 3 den Rotor der Fig. 2 mit eingesetztem Werkzeug,
• Fig. 4 einen Teilquerschnitt durch den Rotor der Fig. 3,
• Fig. 5 eine räumliche Darstellung des Werkzeugs,
• Fig. 6 eine Teildraufsicht auf Rotor und Gegenmesser,
• Fig. 7 eine Darstellung ähnlich Fig. 6 und
• Fig. 8 eine abgewandelte Rotorform.

The invention is explained below with reference to a preferred embodiment shown in the drawing. Show it:

• 1 shows a schematic longitudinal section through a device according to the invention,
• 2 is a side view, partly in longitudinal section, of the rotor of a device according to the invention,
• 3 shows the rotor of FIG. 2 with the tool inserted,
• 4 shows a partial cross section through the rotor of FIG. 3,
• 5 shows a spatial representation of the tool,
• 6 is a partial top view of the rotor and counter knife,
• Fig. 7 is an illustration similar to Fig. 6 and
• Fig. 8 shows a modified rotor shape.

In Fig. 1, a shredding device for waste is illustrated, which has a base frame 1 with a filling shaft 2. At its base there is a motor-driven rotor 3 provided with cutting or chopping tools, which interacts with a counter knife 4. A sliding floor 6 can be moved back and forth in the direction of the double arrow 7 on a base plate 5. It is also driven by a motor, in particular hydraulically, and in each case presses the bottom layer of the unsorted material 8 against the rotor 3. When the push floor 6 is pulled back, the material slips out of the filling shaft so that a new feed process can begin. The chips 9 are ejected downwards.

2, 3 and 4 show the structure of the rotor 3. It has peripheral ribs 10 and intermediate peripheral grooves 11. Both have a V-shaped profile with side surfaces 12 and 13. These are conical and are at an angle of 90 ° to each other. Each circumferential rib 10 is interrupted by a pocket 14 in the form of a prism. This in turn has a V-profile, the flat boundary surfaces 15 and 16 being at an angle of 90 ° to one another. In the middle of the pocket 14, that is to say at its deepest point, the boundary surfaces 15 and 16 form extensions of the side surfaces 12 and 13 of the adjacent circumferential ribs 10. The associated circumferential rib 10 'is not visible in the sectional representations of FIGS. 2 and 3 and therefore only indicated by dashed lines. The deepest point of the pocket 14 has a smaller radial distance from the rotor axis than the base of the circumferential rib 10, which is equivalent to the deepest point of the circumferential groove 11.

A tool holder 17 is fastened in the pocket 14 by welding. It has two flat bearing surfaces 18 which are adapted to the boundary surfaces 15 and 16 a tool 19 fastened on the end face. For this purpose, it has a threaded bore 20 into which a screw 21 penetrating the tool holder 17 engages. The largest cross section of the tool holder 17 corresponds to the square cross section of the tool 19 or is smaller.

The size of the tool 19 is dimensioned such that its surfaces 22 and 23 abut against the boundary surfaces 15 and 16 of the prism and its surfaces 24 and 25 project evenly radially beyond the profile of the circumferential rib 10 '. As a result, there is an overlap with the tool 19 ', which is assigned to the adjacent circumferential rib 10. As shown in FIG. 4, this tool 19' has a position offset in the circumferential direction. The pockets 14 and associated tools 19 are therefore distributed spirally over the rotor circumference. A tool 19 is assigned to each circumferential rib 10.

In Fig. 3 the cutting corner A of the tool 19 is effective. The three other corners B, C and D are well protected. When the cutting corner A is worn out, a different cutting corner B, C or D can be made effective by rotating the tool 19 four times around the axis of the threaded bore 20. If the tool 19 is folded over by 180 °, the cutting corners A ', B', C 'and (not shown) D' can also be made effective.

6 and 7 that the counter knife 4 has peaks 27 which are adapted to the rotating surface 28 of the tool-equipped rotor 3. This results in a serrated cutting gap 29, which determines the maximum cutting depth s, which is constant over the working width. The tools 19 therefore take off the same amount of material one after the other. When all tools have passed through the material to be shredded (e.g. squared timber), the feed can be made by dimension s. This results in a high throughput with a low drive energy. Because of the even gap and the limitation of the depth of cut, there are no stress peaks to fear.

The teeth 27 of the counter knife 4 project radially between the circumferential ribs 10. This leads to an overlap 1 (FIG. 7). Squares and board pieces 30, which are fed parallel to the rotor axis, therefore intersect the cutting gap 29. It is therefore practically impossible that when the tool acts on the material, long wood fibers are torn out, which then jam around the cutting gap 28. Overall, there is a small excess length; the chip granules are uniform in size. In addition, the overlap largely prevents the jamming of materials between rotor 3 and counter knife 4. Since the cutting gap has a limited width, larger material parts cannot pass through it and between the motor and a sieve, which is usually behind the counter knife is arranged, jam. Furthermore, the drawing in of veneer and paper waste, which is often given in packets or in layers, is prevented, which in the past often led to the rotor being blocked.

The corner dimension e of the tools 19 is greater than the width a of the circumferential ribs 10, as shown in FIG. 7. The hatched effective rake face 31 can be changed while the size of the tool 19 remains the same by changing the depth t of the pocket 14 or the width a of the circumferential ribs 10 in the rotor. With a narrow cutting gap 28 there is a small rake face and therefore a fine granulate (chips). In addition, you get a lower drive power with the same number of tools. In any case, large, robust tools 19 can also be used if only a low drive power is available and / or fine chip granules are required.

FIG. 8 shows a slightly modified rotor 103, the circumferential ribs 110 of which have a narrow cylindrical surface 131 or a corresponding curvature on the outer circumference. As a result, the base of the circumferential rib 110 can be kept somewhat wider.

The illustrated exemplary embodiments can be deviated from in many respects without departing from the basic idea of the invention. The rotors described can not only be used for casually running waste shredders, but also for fast-running drum chippers. More than one tool 19 can also be provided per circumferential rib 10. However, a pronounced circumferential rib must still remain, so that no more than 2 or 3 tools should be present in conventional rotor diameters.

Claims (6)

1. Shredder device for refuse, such as wood, paper or plastics, comprising a rotor (3) which has a plurality of circumferential ribs (10, 10', 110) arranged alongside one another over its working width and interrupted by at least one pocket (14), and tool holders (17) welded on in the pockets with tools (19, 19') mounted on the end faces thereof which have a profile projecting radially beyond the rib profile in a substantially uniform manner, and comprising a counterknife (4), the shape of which is adapted to the surface of revolution of the tooled rotor (3), characterised in that the circumferential ribs (10, 10', 110) have an approximately V-shaped profile, that the pockets (14) are formed by rectangular prisms, the lowest point of which is at a smaller distance from the rotor axis than the base of the circumferential ribs (10), and receive not only the tool holder (17), but also the tool (19, 19'), that the tools (19, 19') are square and are secured to the tool holders (17) by means of screws (21) and bear via two surfaces against the boundary surfaces of the prisms, and that the width across corners (e) of the tool (19, 19') measured in the direction of the rotor axis is greater than the width (a) of the circumferential ribs (10).
2. Device according to claim 1, characterised in that the flat boundary surfaces (15, 16) of the prism of the pockets in the region of the tool (19) form extensions of the side faces (12, 13) of the adjacent circumferential ribs (10).
3. Device according to claim 1 or claim 2, characterised in that the tool holders (17) have two flat bearing surfaces (18) adapted to the prism of the pockets.
4. Device according to one of claims 1 to 3, characterised in that the tool (19) has cutting edges (22-25) on both sides.
5. Device according to one of claims 1 to 4, characterised in that the tool (19) only projects so far radially beyond the rib profile that the correspondingly adapted teeth (27) of the counterknife (4) overlap the rib profile in the radial direction.
6. Device according to one of claims 1 to 5, characterised in that the pockets (14) are distributed spirally over the rotor (3).

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