EP0080621B1 - Paper shredder and operating method - Google Patents

Description

The invention relates to a paper shredder with a rotor which is rotatably mounted in a housing with a filling opening and is equipped with shredding tools and has a horizontal axis and an outlet grate and an outlet opening of the housing associated with the outlet grate, the grate being pivoted sideways about a grate axis running parallel to the rotor axis. It also relates to a method for operating this paper shredder.

DE-A-915 520 describes a chopper, namely a crushing mill for chopping field crops. The actual shredding process with this device is not caused by tearing, but by breaking and preferably by grinding the crops, which is the optimal shredding treatment for crops. The good, field crops, however, is fundamentally different from the good "paper" in terms of its specific behavior with regard to crushability and the treatment to be based on it. The purpose of this known proposal is to enlarge the abutment mounting area. By folding in the sieve to be swung out, a screening of the ground material is carried out; if this is not necessary, the sieve remains folded down. In the known crushing mill, the material outlet is not below the rotor, but above the rotor center plane, always directly upstream of the material inlet in the direction of rotor rotation. This means, among other things, that all material that has entered the crushing mill must initially pass through more than half of the treatment path with unchangeably narrow grinding tools in the sense of a grinding process, which already achieves a comparatively fine, constructionally uncontrollable degree of grinding.

DE-A-2 516 014 describes a shredding machine which is intended for waste and other waste. Among other things, the rotor is assigned a grinding path which is not permeable but has ribs running approximately parallel to the rotor axis and a grinding grate which is permeable to comminuted material. The grinding grate, which has roughly axis-parallel grate bars, can be moved horizontally out of the lower part of the housing on rails. When the machine for crushing normal waste is in operation, the material is first thrown against an impact mechanism located above the grinding track and, after the corresponding pre-crushing on the grinding track, is further crushed so that it can fall through the grinding grate. The grinding track and the grating essentially enclose the lower rotor half in the order specified. While the grinding grate should be approximately the same distance from the impact circle of the rotor tools everywhere, it is provided that the distance between the grinding track and the rotor be made smaller in the direction of rotation of the rotor. If there are hard materials that cannot be shredded in the processed material, the grinding track can be swiveled away from the rotor for a short time.

The machine known from DE-A-2 516 014 can also be used for crushing coarse comminution material, such as bulky waste, and even for crushing tough comminution material, such as used tires. In the former case, the crushing takes place essentially through the impact path, while the grinding grate is completely moved out of the action area of the rotor. The grinding path should be arranged just so far from the impact circle of the rotor that a certain amount of re-crushing is effected but there is no fear of the machine blocking. If, on the other hand, old tires or similar tough material to be shredded are to be processed, the grinding track and grinding grate are moved out or swung out of the effective range of the rotor and the rotor tools are only brought into engagement with a tear-off comb or an anvil edge. For the latter application, the direction of rotation of the rotor of the known machine must be reversed. However, the changeover requires a time-consuming and energy-intensive braking of the fast, e.g. with 1500 revolutions per minute, running rotor. It will also be necessary to switch off the rotor if the grinding grate has been moved out of or into the working position. Finally, a major disadvantage of the known machine is that the grating in its position moved out of the operating position hinders the removal of the comminuted material.

From the magazine "cement-lime-gypsum", year 18 (1965), number 11, page 6 is also known for crushing limestone and the like provided impact mill with grates in the lower part. The grids can be pulled out like a drawer from the lower part of the impact mill during overhaul work. Even during operation, a grate half of the grate can be pressed off the rotor to release an outlet gap. For reasons of space within the machine, however, in the exemplary embodiment described, only very slight displacements of the grate basket halves divided approximately in the vertical plane of the rotor axis can be carried out. If, for example, the first half of the grate in the direction of rotation of the rotor is slightly moved away from the rotor when the machine is in operation, a circularly narrowing working area is created between the rotor and the grate, in which, when the machine is used to shred normal waste or paper, the volume that increases greatly during processing Would jam well and jam. If against or also the in Direction of rotation of the second grate basket half is slightly moved away from the impact circle of the rotor tools, there is an opening wedge between the rotor and grate, but the material running off the first grate does not get into the opening wedge at all, but accumulates in front of the removed second grate. The known machine is therefore unsuitable in its design for shredding garbage, paper and similar light material.

Paper shredders must be equally suitable for tearing up individual paper, more or less large bundles, whole files and even goods delivered in bags. The size of the shredding is subject to very different requirements depending on the type of goods entered. A relatively coarse shredding, for example, is sufficient if it is only a question of feeding the paper for further processing. In some cases, smooth paper only needs to be processed to make it pressable. On the other hand, considerable demands are placed on the fineness of the crushing when shredding secret or personal files. The finer the material is to be shredded, the greater the time and energy required for the shredding work. It is therefore of interest to be able to adapt the machine to the respective requirements at short notice and with the rotor running. This is especially true when smaller batches of goods of different types have to be processed one after the other. In order to meet these requirements, three successive shredders have been used in practice up to now, and the processed goods have been processed step by step to the desired final state.

Because of the low specific weight of the shredded paper, a major problem with paper shredders is to guide the air in the machine in such a way that shredded material is blown or sucked in the direction of the machine outlet. This is opposed to the fact that the rotor, as a result of its high number of revolutions, generates an increased pressure on the front - as seen in the direction of rotation - of fixed tools placed in the impact circle of the rotor tools and on the back of the fixed tools a corresponding negative pressure relative to the ambient pressure. As a result, pressure conditions can arise in the machine, which result in that the material being delivered is immediately carried out again with an air flow directed from the inside to the outside in the inlet opening of the machine. At least it is often difficult to bring paper from the machine's feed chute into the engagement area of the rotor tools.

These problems are exacerbated when grids are placed on the underside of the rotor to achieve even paper shredding. With the high speed of rotation of the rotor, the grates can act almost like closed sheets, so that even sufficiently shredded paper does not fall through the grate. In practice, therefore, a move has been made to place a powerful blower on the outlet of the machine, which draws the shredded material through the machining area of the rotor. Since the efficiency of the machine depends on the throughput of shredded material per unit of time and on the energy used, the suction fan should only have to be started up when it is absolutely necessary.

The invention has for its object to improve the paper shredder mentioned at the outset so that it can shred comminution material of a changing type to a respectively specified fineness with the cheapest possible efficiency, determined by the expenditure of energy, time and the fineness of the chips and converting the requirements accordingly when the rotor is running or is to be adjusted.

The solution according to the invention is that the grate consists of two halves divided approximately in the vertical plane of the rotor axis and is arranged below the rotor, that the second grate half in the direction of rotation of the rotor is completely out of the effective range of the rotor tools with the release of a discharge path for approximately tangential or horizontal the comminuted material coming in and ready for use at this point in time is to be pivoted upward, and that the first half of the grate in the direction of rotation of the rotor is to be locked in different pivoting positions relative to the impact circle of the rotor tools. Furthermore, the solution according to the invention for the method for operating the paper shredder is that both grate halves are brought into the working position on the impact circle of the rotor tools for fine shredding, that with coarse material and / or coarser tearing, the second grate half is rotated out completely in the direction of rotation and that at even larger pieces of material and / or even less fine tearing the first half of the grate, especially gradually, e.g. is gradually swung away from the impact circle of the rotor tools.

With the invention it is achieved that the paper shredder with the rotor running - this can have, for example, a run-down time of half an hour - all requirements for fineness of the chips produced, processing time and the lowest possible energy expenditure for different types of paper goods can be adapted in a few simple steps. With the aid of the paper shredder according to the invention, even smaller batches of different types can be processed economically one after the other.

As soon as both grate halves have been brought up to the impact circle of the rotor tools, secret files and even banknotes can be effectively destroyed with the machine. In this case, however, it may be necessary to switch a suction fan to the outlet of the housing in order to achieve sufficient work performance. If the requirements for the fineness of the chips produced are lower, the second half of the grate in the direction of rotation can be swung out completely from the effective range of the rotor tools, so that the comminuted material flies tangentially, i.e. approximately horizontally, from the first grate half that is still in use. Since the second half of the grate is lifted up when it is swung out, it does not hinder the outflow of the comminuted material. When the second half of the grate is swung out, the air flow that otherwise exists on the circumference of the rotor breaks off at the end of the first half of the grate, and the rotor itself generates the desired air flow in the machine for sucking in material to be shredded and for removing the chips that are produced. As a rule, a downstream suction fan is no longer required when a grate half is swung out.

The first half of the rust in the direction of rotation of the rotor must be locked in various swivel positions to the impact circle of the rotor tools. The relative position of counter tools attached to the grate can be adjusted depending on the pivoting position of the grate halves to the impact circle of the rotor tools. The gradual or continuous setting of the first half of the grate in different pivot positions makes it possible to process increasingly coarse material and to achieve increasingly coarse chips. In addition, it is advantageous that when the first grate half is pivoted out, a wedge opens in the direction of rotation between the grate and the rotor.

Such an opening wedge is very favorable in the case of paper which increases in volume during processing. If, finally, the first half of the grate was completely swung out of the action area on the impact circle of the rotor tools, there would be practically no tearing effect without switching on additional tools. The machine according to the invention therefore has a tear-off comb or an anvil edge in front of the entrance to the first half of the grate, which can optionally be inserted or pivoted into the effective range of the impact circle of the rotor tools. Finally, it should be pointed out that the easy swiveling of the grate halves can also be used to release hard or jammed parts or the like by swiveling them out temporarily. While no special changes are made to the grates themselves during this temporary swiveling out of the grate halves, it can, however, be advantageous, when the first grate half is gradually lifted off, to bring counter-tools provided thereon closer to the impact circle of the rotor tools in accordance with the extent of lifting.

• Fi^g. einen Schnitt durch einen Papierzerkleinerer entlang der Linie II in Fig. 2; und
• Fig. einen Schnitt entlang der Linie II-II durch den Papierzerkleinerer nach Fig. 1.

Further details of the invention are explained on the basis of the schematic representation of an exemplary embodiment in the drawing. Show it:

• Fi ^g. a section through a paper shredder along the line II in Fig. 2; and
• Fig. A section along the line II-II through the paper shredder according to Fig. 1st

The paper shredder according to the invention includes a rotor 4 with a horizontal axis 5 which rotates rapidly in operation in a housing 1 with a filling opening 2 and is equipped with shredding tools 3 and which is to be loaded with the material to be shredded, and a two grate halves 6 arranged below the rotor 4 and 7 existing outlet grate and an adjoining outlet opening of the housing 1. The two grate halves 6 and 7 are divided approximately in the vertical plane of the rotor axis 5 and essentially enclose the lower rotor half. Furthermore, the grate halves 6 and 7 can be swiveled out laterally by grate axes 8 and 9 which are horizontally mounted approximately at the height of the rotor axis 5. In the exemplary embodiment, unwanted pivoting out of the grate halves 6 and 7 is prevented by locking bolts 12 engaging in grooves 10 of the cheeks 11 holding the grate halves 6 and 7. Hydraulic piston-cylinder arrangements 13 and 14 are provided for intentionally swiveling the grate halves 6 and 7 in and out, which act on the cheeks 11 of the grate halves 6 and 7. The hydraulic device 14 for lifting off the second grate half 7 in the direction of rotor rotation 15 is designed such that this grate half, including its cheek 11, moves completely out of the area of the lower horizontal tangent of the impact circle 16 of the rotor tools 3 into the position indicated by dash-dotted lines when swiveling out along the indicated swivel circle . The second grate half 7 should be raised so far above the above-mentioned horizontal tangent that when the first grate half 6 in use is rotated horizontally by the rotor 4 or the grate half 6, the material does not hit the second grate half 7. The first grate half 6 in the direction of rotation 15, on the other hand, does not need to be swung out as far as the second grate half 7, but only as far as the dash-dotted position, with the aid of its hydraulic arrangement 13 (along the indicated pivot line), since when the first grate half 7 is lifted off, the comminuted material only needs to be swung out the area of the adjacent vertical tangent of the impact circle 16 falls.

While the second half of the grate 7 in the direction of rotation 15 can either only be moved completely to the impact circle 16 or swiveled completely away from it, the in Direction of rotation 15 first grate half 6 in various intermediate positions perform valuable services. In the intermediate positions, it may be expedient to raise or lower the counter tools 17 and 18 assigned to the grate half 6, at least in the case of intended continuous operation, according to the distance from the impact circle 16. If the grate half 6, which is first in the direction of rotation 15, is partially or completely pivoted out of the effective range of the impact circle 16 of the rotor tools 3, further tools, for example an anvil flap 19 to be moved in or into the effective range of the impact circle 16, are required for comminuting the material. The material is then comminuted between the rotor tools 3, which are pushed radially outward by centrifugal force, and the anvil edge 20. A hydraulic cylinder arrangement 21 can also be provided to adjust the anvil flap 19.

In order to enable the setting and pivoting of the grate halves 6 and 7 including the associated cheeks 11 while the rotor 4 is running in accordance with the accident prevention regulations, the housing 1 is also made so large in the lower region that the parts which may be swiveled out can be accommodated within the housing and during the Swinging out the operator can not be injured by material thrown from the rotor.

Claims (9)

1. Paper shredder, comprising a rotor (4) with horizontal axis (5), rotatably journalled in a housing (1) with filling opening (2) and equipped with shredding tools (3), and comprising an outlet grating (6, 7) and an outlet opening of the housing associated with the outlet grating (6, 7), wherein the grating can be pivoted about a grating axis parallel to the rotor axis (5), wherein the grsting consists of two halves (6, 7), divided approximately in the vertical plane through the rotor axis (5), and is disposed underneath the rotor (4), the second halfgrating (7) in the rotor rotational direction (15) can be pivoted away upwards completely out of the range of action of the rotor tools (3) to open a discharge path for shredded material coming approximately tangentially and horizontally from the first half- grating (6) ready for use at this instant, and the first half-grating (6) in the rotational direction (15) of the rotor (4) can be arrested in various pivoted positions relative to the beating circle (16) of the rotor tools (3).

2. Paper shredder according to claim 1, wherein the relative position of counter-tools (17, 16) fitted to the first half-grating (6) can be adjusted relative to the beating circle (16) of the rotor tools (3) according to the pivoted position of the half-grating (6).

3. Paper shredder according to claim 1 or 2, wherein (4) and the range of pivoting of the grating are so surrounded by the houging (1) that actuation of the half-gratings (6, 7) during continuing operation is admissible.

4. Method of operating the paper shredder according to one or more of claims 1 to 3, wherein, for finely shredding, both the halfgratings (6, 7) are brought into the working position at the beating circle (16) of the rotor tools (3), in the case of coarse material and/or coarser shredding, firstly the second half-grating (7) in the rotational direction is pivoted away entirely and, in the cage of still larger material pieces and/ or less fine shredding, the first half- grating (6) is pivoted away especially gradually, for example by steps, from the beating circle (16) of the rotor tools (3).

5. Method according to claim 4, wherein the second half-grating (7) in the rotational direction (15) is temporarily completely pivoted away in order to release hard or jammed pieces or the like.

6. Method according to claim 4, wherein the first half-grating (6), with the second half-grating (7) completely pivoted away, is temporarily pivoted away partly or entirely from the beating circle (16) of the rotor tools (3) in order to release hard pieces.

7. Method according to one or more of claims 4 to 6, wherein an anvil edge (20) or a shredding comb, provided above the rotor (4), is brought, with the second half-grating (7) pivoted away, into the working position at the beating circle (16) of the rotor tools (3).

6. Method according to one or more of claims 4 to 7, wherein counter-tools (17, 16), provided at the first half-grating (6) in the rotational direction (15), are brought, with the second half-grating (7) pivoted away, nearer to the beating circle (16) of the rotor tools (3).

9. Method according to one or more of claims 4 to 6, wherein the adjusting or pivoting of the half- gratings (6, 7) is carried out during operation of the machine with the rotor running.

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