A DEVICE FOR CUTTING ACTION UPON OBJECTS AND USE THEREOF

Abstract: A device for cutting action upon objects comprises cutting means (2) having cutting edges (1) and being rotary-arranged, which is characterized in that the cutting means (2) comprise a number of discs arranged side by side being provided with a substantially circular periphery and having cutting edges for said action. The invention also relates to the use of this device for cutting action upon sacks, string bags, bags and cardboard boxes for opening thereof and releasing of the contents therein as well as for cutting action upon piece-like, sticky material.

Description: A DEVICE FOR CUTTING ACTION UPON OBJECTS AND A USE THEREOF BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates to a device for cutting action upon objects, which comprises cutting means having cutting edges and being rotary arranged. Even though the invention relates to such devices adapted for cutting action upon objects in general, it is particularly directed to cutting action upon such objects as sacks, string bags, cardboard boxes and the like, where it is desired to open them for releasing objects located therein. Such contexts in which the device is a part of a system for handling compostable waste material are especially concerned, in which the device has in particular the task to open string bags and the like, in which waste material is enclosed when it is supplied to the system. For the sake of a non-limitative example the device defined in the introduction will hereinafter be described with respect to such an application. Such devices are also suited for cutting action upon such objects as vehicle tyres, which are to be decomposed or cut into smaller parts for the sake of recycling when they have been worn out. The device will therefore further on in the description be described with respect to this application. The prior art within this field for opening sacks, string bags, cardboard boxes and the like refers primarily to different types of devices, in which different types of standing knives are used and they are accordingly of another type than that defined in the introduction by the fact that the cutting means are not rotary, in which the knives are allowed to overlap each other so as to by that open the sacks, the string bags etc and release the material enclosed therein, which for example may be household garbage, industrial waste and the like and which is desired to be taken care of for further handling for different purposes, such as recycling purposes and composting purposes, for different reasons. However, a disadvantage of such devices is the tendency for some of the material or objects exerted to the cut¬ ting and dividing action may hook or stick to the knives of the devices, especially if the material or the object has gluey character, which makes the knives less efficient and by that im- pairs the total function of the device. Different types of mills for cutting action upon objects are also known according to prior art. These utilize mostly rotary means, which on the periphery thereof are provided with different types of projections, which may be designed more or less pointed so as to engage with and by that achieving cutting action upon objects brought into contact with said projections by rotation of the rotating means. Couples of rotating means are often utilized, between which a slit is arranged and into which slit the material is brought to pass through the rotation of the means and the engaging action of the projections. The width of the slit is then of course depending upon the material to be exerted to the cutting action and the size and design of said projection. However, also this type of device has the disadvantage that the material to be exerted to the cutting action gets stuck and re¬ mains on the projections, which is the risk especially if the ma¬ terial is gluey or sticky, which is often the case in handling of different types of waste material and the sacks, string bags, cardboard boxes and the like in which this material is stored. SUMMARY OF THE INVENTION An object of the present invention is to provide a device for cut¬ ting action upon objects, which device is well suited for cutting action upon objects which through glueyness, stickiness or the design thereof have a tendency to hook or adhere to the cutting means of the device. The device according to the invention is also intended to be a functional and from the economical point of view preferred alternative to the device according to the prior art within this field. The device according to the invention for cutting action upon objects, which comprises cutting means having cutting edges and being rotary arranged, is therefore characterised in that the cutting means comprise a number of discs arranged side by side, being provided with a substantially circular periphery and having cutting edges for said action. By the fact that the cutting means comprise a number of cutting means arranged side by side the cutting action is allowed to take place from several points upon an object extending over a region in which a number of cutting means are present, and by the fact that the cutting means comprise discs being provided with a substantially circular periphery and having cutting edges for said action the advantage is particularly obtained that these result in a very small amount, if any, of material after this has been exerted to the cutting action of the cutting means. Thus, owing to the design of the cutting means it is possible to in a high degree avoid that material or objects having a high toughness, stickiness or has such a design that they tend to hook to projections or the like hook to the cutting means and follow them also after the very cutting action has been achieved. According to a preferred embodiment of the device according to the invention the cutting edges are designed substantially with¬ out sharp edges transversally to the circumferential direction of the discs, which means that these have no sawtooth-like outline, but they follow a smooth path in absence of remarkable changes of direction. However, the cutting edge is itself more or less pointed. Through this design of the cutting edges the risk of parts of the material exerted to or which has been exerted to the cutting action also thereafter will follow the cutting edge during the ro¬ tation of the cutting means is minimized. Furthermore, the cutting edge has then not the type of sharp points, which in saw blades and the like after a certain time of use tend to be made blunt, but they do instead constitute a smooth surface, which may easily be sharpened when it after a period of time starts to get blunt. According to a further preferred embodiment of the device ac- cording to the invention this is characterized in that the cutting edges are wave-shaped in the circumferential direction of the discs, i.e. the cutting edges have a distance to the center of the disc, which is varying without, as for a saw blade, having any point formations in this circumferential direction. The total length of the cutting edge gets by that longer than would there not be any wave shape and the distance of the cut¬ ting edges to the central of the disc would be constant. Upon rotation in a certain direction the front surface seen in the di- rection of the rotation of each wave will form a cutting surface and by that be made blunt earlier than the rear surface of this wave. When these front wave surfaces have been made blunt it is only necessary to turn the discs or change the direction of rotation, so that the previous rear wave surface now instead will function as a front wave surface, by which it is possible to util¬ ize the higher degree of sharpness still there for these surfaces. According to a further preferred embodiment of the device ac- cording to the invention the rotary cutting means are movably carried in a way allowing a translation movement thereof. This is particularly preferred in the case in which the objects exerted to the cutting action are fed to or located between a surface located directly in front of the cutting means and the cutting means and there is something among these objects that is too hard to be cut and which if it were not possible to displace the cutting means could cause a strong wear or deterioration of the cutting edge and possibly block further ro- tation of the cutting means. Thus, this characteristic is impor¬ tant both for a long lifetime of the cutting means and the continuous function of the device as such. According to a further preferred embodiment of the device this comprises means arranged between the cutting means for wip¬ ing of object parts followed the rotation of the cutting means after being exerted to the cutting action thereof. The risk that the objects or the material exerted to the cutting action would follow the cutting means in the rotation thereof and prevent the function of the latter in a continuous cutting action is thereby further prevented. According to a further preferred embodiment of the device the wiping means are bent, at least in the region of the periphery of the cutting means in the direction of rotation of the cutting means. It is then in particular valid that the wiping means are arranged close downstream of the region in which the cutting action of the cutting means takes place with respect to the di- rection of rotation of the latter. A particular advantage is obtained by means of this embodi¬ ment by the fact that object parts remaining on the cutting means and being wiped off the cutting means by the wiping means to a smaller extent risk to be wedged up between the cutting edge and the wiping means then should there be an op¬ posed bending or no such bending be there at all. According to a further preferred embodiment of the device, the cutting means are arranged opposite to a surface being utilized as counter surface in the cutting action and between which and the cutting means the objects exerted to said cutting action are localized. It is by that possible to in an advantageous way utilize the sur¬ face so as to facilitate the cutting action of the device by contributing to in a certain degree keep the objects to be exerted to this cutting action in place with respect to the cutting means. It should be realised that this surface not in any way necessarily prevents objects exerted to said cutting action from simultaneously therewith being fed between the cutting means and the surface, in which the fed may depend upon on one hand the rotation of the cutting means and on the other that any par¬ ticular feeding arrangement feeds the objects in this direction. This is especially the case in a composting plant, in which the device for cutting action primarily has the function as sack opener and primarily functions as a station to which these ob¬ jects, preferably sacks, are delivered for being transported fur¬ ther on in the system after being exerted to said cutting action. According to a further preferred embodiment of the device ac¬ cording to the invention this comprises a first grid structure, against which objects to be exerted to a cutting action are in¬ tended to be placed and through the grid openings of which the cutting means are designed to be brought for achieving the cut¬ ting action. It will then be possible to more completely decompose the ob- jects exerted to a dividing action and it will then be possible to completely decompose objects being unmovable between the grid structure and the cutting means only by moving the cutting means with respect to the grid structure. A grid structure is in a preferred embodiment located under the cutting means in a substantially horizontal plane, but also other positionings are possible. According to a further preferred embodiment of the device ac¬ cording to the invention this comprises means for compressing objects before and/or at the same time as these are exerted to a cutting action. It will by that be possible to use the device according to the in¬ vention to create a cutting action, and then in particular a de- composing action, also upon objects being made of such a material and with such a structure thereof, that these, should they not be held by the means for compressing, would either have a shape not being suited for said cutting action or for this or any other reason would tend to move in an attempt to obtain a cutting action thereof. The invention also relates to a use of the device as defined above for in particular cutting action of sacks, string bags, bags and cardboard boxes for opening thereof and releasing of the contents therein. This is particularly valid when at least a part of the contents in said sacks is waste material being composta¬ ble and designed to be composted after said release. The invention also relates to a use of a device as defined above for cutting action upon piece-like, sticky material, in which es- pecially cutting action upon vehicle tyres is intended, in which the cutting action relates to decomposing thereof into strips. Further advantages and preferred characteristics of the inven- tion will appear from the following description and the other claims. BRIEF DESCRIPTION OF THE DRAWINGS With reference to the appended drawings, below follows a detailed description of preferred embodiments of the invention in the form of non-limitating examples. In the drawings: Fig 1 is a partially sectioned side-elevation view of the device according to the invention, including means for supplying and feeding away, Fig 2 shows the device according to Fig 1 from above, Fig 3 is a partially sectioned side-elevation view of an alterna¬ tive embodiment of the device according to the invention, particularly suited for cutting action upon vehicle tyres, Fig 4 shows the device according to Fig 3 from above, Fig 5 is a side-elevation view of an alternative embodiment of the device according to the invention, Fig 6 shows the device according to Fig 5 from above, and Fig 7 is a side-elevation view of a cutting means, in which the wave shape thereof in a circumferential direction is partially shown. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The device according to the invention for cutting action upon objects is shown in Fig 1. Objects as sacks, bags, string bags, cardboard boxes and the like, in which household waste and in¬ dustrial waste are stored are particularly concerned. The device comprises cutting means 2 having cutting edges 1 and being rotary arranged. The cutting means 2 comprise a number of discs arranged side by side, being provided with a substantially circular periphery and having cutting edges for said action. The discs 2 are in a preferred embodiment comparatively thin and have each a thickness being substantially constant over the en¬ tire cross-section thereof, except from the cutting edge regions, where they taper so as to form a point. However, it should be realised that it is not necessary that the discs are particularly thin or have a thickness being constant over the cross-section thereof. They may even be partially stuck together while forming one single piece. However, in the embodiments of the device according to the invention shown they are separated and arranged side by side on a common carrier 3, which has the form of an axle centrally extending through the discs and being driven by a power means mounted at the device and rotating the cutting means, which power means here is an electric motor 4 adapted for that purpose. The cutting means 2 are carried by cutting members 5 belong¬ ing to the device. The cutting members 5 are arranged to allow a translation movement of the cutting means 2. This is in the preferred embodiments possible by the fact that the carrying members 5 are pivotably connected to a stationary structure 6 in connection to the device. The carrying members 5 are in Fig 1-4 two parallel arms, which are substantially in the middle of the length thereof penetrated by the axle 3 on which the cutting means 2 are arranged and they form by that a yoke in which the assembly of the axle 3 and the carrying means 5 is suspended. The structure 6, in which the carrying means are hingedly ar- ranged is in Fig 1 and Fig 2 a container for a means 7 for supplying the objects to be exerted to a cutting action to the container 8 in connection thereto, in which the cutting action is intended to take place and in which the cutting means 2 are ar¬ ranged. The supplying means shown in Fig 1 and 2 is a rotary spiral driven by a motor 9. Sacks, string bags, bags and the like to be fed to the cutting means 2 by the supplying means 7 are supplied to the supplying means through a hopper-like member 10. The carrying means 5 are in end opposed to the end in which they are hingedly arranged connected to a transversal element 11. Elongated wiping means 12 are also extending from the transversal element 11 in between the respective cutting means 2 and towards the centre thereof. As appears from especially Fig 1 , the wiping means have a slight bend in the direction of rotation of the cutting means, which contributes to an easier wiping off from the cutting means 2 of such material that possibly follow the cutting means after they have passed the region for the cutting action, which here is the lower part of the container 8, than should the bend be in the opposite direction or there would be no bend at all. Substantially directly under the portion of the wiping means 12 where these are in the region of the cutting edges, and where material wiped off by the wiping means 12 may be expected to fall down therefrom, an outlet 13 is arranged in the container 8. In the outlet channel 13 is for the rest a means 14 for feeding the material exerted to the cutting action away arranged, which means here is a spiral similar to the spiral forming the supplying means 7. The container 8 has a surface 15 utilized as counter surface in the cutting action and between which and the cutting means the objects exerted to said cutting action are localized. As appears from Fig 1 this surface 15 is formed by the bottom of the container 8. The distance between the cutting edges 1 and this surface 15 is comparatively short, preferably in the region of 0-10 mm, but more preferred in the region 1-5 mm and most preferred approximately 3 mm. This is particularly valid when the objects intended to be exerted to a cutting action are sacks, string bags, cardboard boxes and the like with the aim previ¬ ously mentioned. The distance between the cutting edges 1 of adjacent cutting means 2 is in the order of 3-10 cm, preferably approximately 5-7 cm. The cutting means 2, or at least the cutting edges 1 thereof, are preferably manufactured of a AR steel, i.e. a wear steel, which guarantees a long lifetime and a good economy. An alternative embodiment of the device according to the invention is shown in Fig 3 and 4, which in practice has turned out to be well suited for cutting action upon piece-like, sticky material, especially cutting of vehicle tyres into strips. The surface utilized as counter surface with respect to the cut- ting edges in the cutting action is here formed by a first grid structure 16, against which objects to be exerted to the cutting action are adapted to be placed and through the grid openings 17 of which the cutting means 2 are adapted to be moved for obtaining the cutting action. The device comprises a respective grid opening 17 for each of the cutting means 2. The width of the grid openings is only slightly larger than the thickness of the cutting means 2, which stabilizes the object to be exerted to the cutting action and prevents that this to any larger extent is folded into the grid openings 17, when this is exerted to this cutting action. The device also comprises means 18 for compressing objects to be exerted to the cutting action before and/or at the same time as these are exerted to this action. The means 18 for com- pressing comprise a second grid structure, which is adapted to press objects to be exerted to a cutting action between itself and the first grid structure 16. Also the second grid structure 18 is provided with grid openings, through which the cutting means 2 are arranged to be moved. These grid openings correspond to the grid openings 17 of the first grid structure 16, with respect to the number as well as the positioning with respect to the number and positioning of the cutting means 2. The means 18 for compressing are movable, in this embodiment in the vertical direction, with respect to the surface 15 on which the objects rest. This movability is preferably achieved by the fact that the second grid structure 18 is displacable by means of hydraulic, in this embodiment vertically, with respect to a stationary frame 19 connected to the device. Also the cutting means 5 are for the rest in this embodiment hingedly connected to the frame 19, which by that also corresponds to the structure part 6 previously mentioned. The device also comprises means for holding the objects when these are exerted to the cutting action. These means are in the preferred embodiment shown in Fig 3 and 4 the first and second grid structure 16 and 18, respectively. The supplying means 7 is in the embodiment shown in Fig 3 and 4 an endless belt instead of a spiral, as in Fig 1 and 2. The objects to be exerted to a cutting action, in this case vehicle tyres, are placed on this supplying means 7 through the hopper¬ like member 10 and sent to the device where they are exerted to said cutting action while being compressed between the means 18 and the grid structure 16. It is for the rest indicated in Fig 3 by dashed lines a position in which the cutting edges 1 may be present in a position in which the cutting means 2 are pivoted downwardly, in which position a cutting action takes place. Furthermore, only one wiping means 12 is indicated by a dashed line in Fig 4, but it should be realised that such means are placed between all the cutting means. A further embodiment of the device according to the invention is shown in Fig 5, in which the cutting means 5 here are arms of a crane device 20 and by that arranged in series and not as above in parallel to each other. The support structure 6 is here formed by a part of a container in which the objects to be exerted to the cutting action are present. The cutting means 5 may also here be considered to be hingedly connected to the support structure 6 in a way allowing a vertical displacement of the cutting means 2. The crane device 20 may also be rotary ar¬ ranged with respect to the support structure 6. This embodiment also allows to a large extent displacement of the cutting means forwardly and rearwardly as well as in the lateral direction in the container, which may be desired should the cutting means be small with respect to the container and the objects to be ex¬ erted to the cutting action not be supplied to the cutting means 2 by any particular arrangement, but these had instead to be moved to enter into contact with the objects to be cut. Fig 5 and 6 are strongly simplified, but it should nevertheless be understood that the principles mentioned above with respect to the positioning and the design of the wiping means with re¬ spect to the direction of rotation of the cutting means are also applicable to this embodiment. Fig 7 shows a preferred embodiment of a cutting means 2, in which the cutting edges 1 are wave shaped in the circumferen¬ tial direction of the disc forming the cutting means 2. For a good technical effect in connection with cutting action upon for example string bags, sacks, bags and the like it has in practice turned out to be suitable for releasing the content thereof to have a disc diameter in the order of 800 mm, a distance between the wave top and the wave bottom of about 40 mm as well as a distance between adjacent wave tops of about 150 mm. The cutting action upon exactly string bags, bags, sacks and the like for the purpose mentioned above a speed on the cutting means in the order of 5-100 revolutions/minute, is preferably utilized, more preferably 10-50 revolutions/minute and most preferred 20-25 revolutions/minute. However, considerably higher cutting means speeds are utilized for cutting action upon tyres. The described invention is of course not in any way restricted to the embodiments described above, but many possibilities to modifications thereof would be apparent to a man skilled in the art. The idea of the invention is instead to be primarily interpreted as restricted by the appended claims. The preferred embodiments described above have for example devices in which counter surfaces 15, holding and compressing means 16, 18 extend in a substantially horizontal plane and in which the translation movement of the cutting means takes place mainly in the vertical direction. Such embodiments have turned out to be particularly advantageous. However, it should be realised that this not in any way prohibit the utilization of positionings and translation movements departing from those mentioned above. Also such alternatives are namely covered by the appended claims defining the idea of the invention. Furthermore, it has to be pointed out that the expression "without sharp edges transversally to the circumferential direction of the discs" means that no sharp edges are there transversally to the cutting edges 1 along the extension thereof. Thus, if a hand is moved along the cutting edge 1 of a cutting means this will not meet any sharp edge or point independently in which direction along the edge the hand is moved. "Wave-shaped" means softly shaped waves without any tendency to such sharp waves that these form pointed wave tops or bottoms.

Claims: Claims 1. A device for cutting action upon objects, comprising cutting means (2) having cutting edges (1 ) and being rotary arranged, characterized in that the cutting means (2) comprise a number of discs arranged side by side, being provided with a substan¬ tially circular periphery and having cutting edges for said action. 2. A device according to claim 1 , characterized in that the cut- ting edges (1 ) are designed substantially without cutting edges transversally to the circumferential direction of the discs. 3. A device according to claim 1 or 2, characterized in that the cutting edges (1 ) have a wave shape in the circumferential di- rection of the discs. 4. A device according to any of the preceding claims, charac¬ terized in that an axle (3) is arranged as a carrier in common for the cutting means (2). 5. A device according to any of the preceding claims, charac¬ terized in that the rotary cutting means (2) are movably carried by carrying members (5) belonging to the device in a way allowing a translation movement thereof. 6. A device according to any of the preceding claims, charac¬ terized in that the distance between the cutting edges (1 ) of adjacent cutting means (2) is in the order of 3-10 cm. 7. A device according to any of the preceding claims, charac¬ terized in that it comprises means (12) arranged between the cutting means (2) for wiping object parts carried on by the cutting means (2) after they have been exerted to a cutting action of the cutting means. 8. A device according to claim 7, characterized in that the wiping means (12) are arranged immediately downstream of the region in which the cutting action of the cutting means (2) takes place with respect to the direction of rotation of the latter ones. 9. A device according to claim 7 or 8, characterized in that the wiping means (12) are bent in the direction of rotation of the cutting means at least in the region of the periphery of the cutting means (2). 10. A device according to any of the preceding claims, char¬ acterized in that it comprises a surface (15) utilized as a counter surface in the cutting action and between which and the cutting means (2) the objects exerted to the cutting action are located. 11. A device according to any of the preceding claims, char¬ acterized in that it comprises a first grid structure (16), against which objects to be exerted to a cutting action are ar¬ ranged to be placed and through the grid openings (17) of which the cutting means (2) are designed to be brought for obtaining the cutting action. 12. A device according to any of the preceding claims, char¬ acterized in that it comprises means (18) for compressing objects before and/or at the same time as they are exerted to a cutting action. 13. A device according to claims 11 and 12, characterized in that the compressing means (18) comprise a second grid structure, which is designed to press objects to be exerted to a cutting action between itself and the first grid structure (16), and through the grid openings of which the cutting means (2) are designed to be moved. 14. A device according to claim 12 or 13, characterized in that the compressing means (18) are movable with respect to the surface (15), on which the objects rest. 15. A device according to any of the preceding claims, charac¬ terized in that it comprises means (16, 18) for holding the ob¬ jects while they are exerted to the cutting action. 16. A use of a device according to any of claims 1-10 for cutting action upon sacks, string bags, bags and cardboard boxes for opening them and releasing the contents thereof. 17. A use according to claim 16, in which at least a part of the contents in the sacks, string bags, bags and the cardboard boxes are compostable waste material designed to be com¬ posted after said release. 18. A use of a device according to any of claims 1-15 for cutting action upon piece-like, sticky material. 19. A use according to any of claims 1-15 or 18 for cutting ac¬ tion upon vehicle tyres, in which the cutting action relates to decomposition thereof in strips.

Inventors: SCHMUTZ URS, SCHMUTZ, URS
Applicants: BKS NORDIC AB
Application year: 1997
Main classification: B02C18
IPC codes: B02C18, B65B69