The invention relates to a device for separating sheets of paper and cardboard in accordance with Claim 1. European Patent Application
In order to avoid this disadvantage, the device is designed in accordance with Claim 1. In the device according to the invention the sorting tines are fixed securely on an inner drum, and the cardboard is stripped off the sorting tines by a likewise sturdy outer drum, the outer drum moving more or less in the longitudinal direction along the sorting tines. By this measure, a sheet of cardboard will be removed accurately and gradually from the sorting tines.
In accordance with one embodiment, the device is designed according to Claim 2. This produces a simple and sturdy device in which the inner drum and the outer drum can rotate in a stable manner.
In accordance with one embodiment, the device is designed according to Claim 3. By supporting the outer drum with wheels in four places, a simple construction which can be executed in a stable manner is obtained.
In accordance with one embodiment, the device is designed according to Claim 4. By pushing the inner drum towards the belt conveyor, the sorting tines are pushed additionally into the sheets of material to be sorted, and the cardboard sheets will stick better on the sorting tines.
In accordance with one embodiment, the device is designed according to Claim 5. By clamping both the inner drum and the outer drum between the support and the pressure rollers, it is ensured that said drums are guided carefully and that the belt conveyor can travel at a higher speed, with the result that the device can have a great capacity.
In accordance with one embodiment, the device is designed according to Claim 6. By designing the sorting tines with at least one groove, it is ensured that cardboard sticks better on the sorting tine, with the result that heavier sheets of cardboard are also sorted correctly out of the stream of sheets of paper and cardboard.
In accordance with one embodiment, the device is designed according to Claim 7. By making the belt conveyor and/or the pressure rollers spring-loaded, it is easily possible to accommodate thickness differences in the sheets of paper and/or cardboard lying on the belt conveyor without overloading of the construction occurring.
In accordance with one embodiment, the device is designed according to Claim 8. By this measure, the supports are of a simple design and because the sorting tines can move in the longitudinal direction relative to the belt conveyor, it is not necessary to have exact synchronization in the rotation of the rotating drums with the sorting tines and the movement of the belt conveyor.
In accordance with one embodiment, the device is designed according to Claim 9. By this measure, the sorting tines always stay in the same position relative to the belt conveyor, and the supports can be positioned accurately relative to the sorting tines.
In accordance with one embodiment, the device is designed according to Claim 10. In this case the belt conveyor is of a simpler design, in which the tines project through apertures in the belt conveyor, and the belt conveyor can precisely support the cardboard and paper sheets.
In accordance with one embodiment, the device is designed according to Claim 11. By this measure, the outer drum can be fitted accurately around the sorting tines, so that it is easy for the outer drum to remove the cardboard impaled upon the sorting tines.
In accordance with one embodiment, the device is designed according to Claim 12. By this measure, it is ensured that the sorting tines always project through holes in the outer drum, so that the inner drum stays in an accurate position relative to the outer drum.
The invention is explained below with reference to an exemplary embodiment by means of a drawing, in which:
The sorting device 1 consists of a frame 25 having on the upper side two side walls 14 between which an endless belt conveyor 13 is provided. The endless belt conveyor 13 runs over a drive pulley 20 and a return pulley 20A and is guided by support rollers 21 between the side walls 14 and held taut by the return pulley 20A. The belt conveyor 13 is driven mechanically by a drive 22 (not shown) in a direction of conveyance 32. The mixture of sheets of paper and cardboard to be sorted is supplied by a supply belt 2 to the belt conveyor 13, in which process, in order to make sorting of the sheets possible, the speeds of the supply belt 2 and the belt conveyor 13 are selected in such a way that individual sheets are deposited one after the other in a single layer on the belt conveyor 13.
Sheets of cardboard and paper lying on the belt conveyor 13 are conveyed along underneath sorting tines 3, during which the sorting tines 3 lift sheets of cardboard off the belt and deposit them on a first discharge belt 9. Sheets of paper remain lying on the belt conveyor 13 and are conveyed to a second discharge belt 12. At the point where the sheets of paper fall off the belt conveyor 13 onto the second discharge belt 12, guide plates 11 are provided in order to prevent the sheets of paper from falling onto the ground. The second discharge belt 12 conveys the sheets of paper to a storage place and/or a place where the paper is processed further.
The preceding text has referred a number of times to the separation of paper and cardboard. It is pointed out here that the term cardboard also includes those types of paper which have a resistance to tearing which is comparable to that of cardboard and are consequently unsuitable for the further processing operations which paper will undergo after being sorted.
The sheets of cardboard which are lifted off the belt conveyor 13 by the sorting tines 3 move upwards along with the sorting tines 3. Through the difference in diameter between the inner drum 6 on which the sorting tines 3 are fixed and the outer drum 5 rotating about said inner drum and having apertures 26 (see
Support rollers 16 are provided on the outside of the side walls 14 on the frame 25. On these support rollers the outer drum 5 can rotate about a top axis of rotation 7 which is preferably more or less perpendicular to a direction of movement 32 of the belt conveyor 13. The outer drum 5 is completely open on the inside and has a guide edge 4, as a result of which the outer drum 5 always stays more or less in the same position above the belt conveyor 13. The inner drum 6 rests on the bottom part of the outer drum 5, which inner drum rotates with the outer drum 5 about a bottom axis of rotation 8. The sorting tines 3 are fitted in the inner drum 6 in such a way that they can be changed easily in the event of wear and also for the purpose of fitting the inner drum 6 in the outer drum 5.
In order to ensure that the inner drum 6 rotates with the outer drum 5 and does not jerk upwards as a result of the load on the sorting tines 3, pressure rollers 17 are preferably provided at the position of the support rollers 16, each pressure roller being fixed by means of springs 18 on a support 19. The springs 18 make some movement of the inner drum 6 relative to the outer drum 5 possible. In the region where the inner drum 6 and the outer drum 5 rotate above the belt conveyor 13, the belt conveyor 13 is supported by a support plate 15 which by way of springs 23 rests upon a support 24 fixed on the frame 25. Because of the spring-loaded support plate 15 and also because of the possibility of movement of the inner drum 6, the sheets of paper and cardboard lying on the belt conveyor can be of changing thicknesses without causing any problem.
A sheet 28 is shown lying flat on the belts 29, which sheet 28 moves with the belt conveyor 13 in the direction of movement 32. More or less in synchronism with the movement of the belt conveyor 13 in the direction 32, the inner drum 6 and the outer drum 5 rotate in a direction 27 along with the belt conveyor 13. As stated above, the sorting tines 3 are fitted on the inner drum 6, for example by being screwed onto a screw thread provided in the inner drum 6. Of course, other constructions are possible with, for example, screwed-in bushes in which the sorting tines 3 are clamped.
The sorting tines 3 project through the slotted holes 26, which in the circumferential direction are of such length that the relative movement of the sorting tines 3 which has occurred in relation to the outer drum 5 through the difference in diameter between the inner drum 6 and the outer drum 5 is possible in the slotted holes 26. The slotted holes 26 are of a width which precisely encloses the external diameter of the sorting tines 3. The inner drum 6 is pressed against the outer drum 5 by the pressure rollers 17. This means that, as the space between the belt conveyor 13 and the sorting tines 3 decreases, the sorting tines 3 are pressed into the sheet 28, so that on further rotation of the inner drum 6 and the outer drum 5 the sheets 28 are carried along, as shown by the sheet 31 hanging on the sorting tines 3.
During the sorting, use is made of the situation where, if a sorting tine 3 is pressed on a sheet of paper, the paper then gives way and will fold into the longitudinal groove 36 between the belts 29, and springs back again to a limited extent as soon as the sorting tine 3 moves back up again relative to the sheet. The paper may possibly tear, so that it is ultimately hanging loosely around the sorting tine 3 and will not be lifted up by it. However, because of the thickness of a sheet of cardboard, the latter cannot fold into the longitudinal groove 36, with the result that the cardboard will acquire a small tear and will grip around the sorting tine 3. Through the difference in grip around the sorting tine 3, a sheet of cardboard is lifted by the sorting tines 3 and a sheet of paper remains lying on the belt conveyor 13.
The sorting tine 3 is designed with two grooves 33 and a blunt tip 34, by means of which the sorting tine 3 will press sheets 28 lying on the belts 29. The person skilled in the art will understand that by means of the blunt tip the sheet of paper lying on the belts 29 is pressed away into the longitudinal groove 36. The blunt tip is of such dimensions (for example, as the smallest surface area a diameter of 1 mm) that the tip 34 tears open cardboard, with the result that the latter will grip around the sorting tine 3. The sorting tine 3 can also be designed with one groove 33 or with more than two grooves 33.
In the embodiment described above the drive 22 not only drives the belt conveyor 13, for example by driving the drive pulley 20 and possibly also the return pulley 20A, but the drive 22 also rotates the inner drum 6 and outer drum 5 by driving the support rollers 16. Owing to the fact that it is possible that some slip may occur between the belt conveyor 13 and the drive pulley 20 and/or between the outer drum 5 and the support roller 16, it can happen that the rotation of the outer circumference of the outer drum 5 and the movement of the belt conveyor 13 are not fully in synchronism. This means that it is necessary for the sorting tines 3 to be able to move in the longitudinal direction relative to the belt conveyor 13 and the belts 29. The construction shown here, in which the outer drum 5 rolls on support rollers 16, can be replaced with a comparable result by a construction in which the outer drum 5 is provided with a central shaft with bearings. Other constructions of the common rotation of the inner drum 6 and the outer drum 5 are also possible.
In order to make precise support of the sheets 28 possible, in this embodiment holes 41 are provided in the belt conveyor 13, which holes are positioned in such a way that a sorting tine 3 always projects into the hole 41. The holes 41 are dimensioned in such a way here that the sorting tine 3 presses a sheet of paper 28 into the hole so that the sheet does not stick on the sorting tine 3, while, if the sheet 28 is made of cardboard, then the sorting tine 3 will pierce the cardboard, and the cardboard sticks in a groove 33 of the sorting tine.
Apart from the synchronization shown here of the movements of the belt conveyor 13 and the outer drum 5 by means of teeth, said synchronization can also be achieved in another way. This could be by direct connection of the movement of the belt conveyor 13 to drive pulley 20, for example by providing the belt conveyor 13 on the inside with teeth and likewise designing the return pulley 20A with a connection interacting with said teeth, connecting the rotation of the drive pulley 20 by means of chains to the rotation of the support roller 16 and subsequently connecting the rotation of said support roller 16 by means of teeth to the rotation of the outer drum 5.
Through the measures shown, it is possible for the device to have a great capacity. The sheets of paper and cardboard can be supplied in a single layer at speeds of 50 - 60 m/minute, the inner drum 6 and the outer drum 5 having a speed corresponding to those speeds.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.