Field of invention

The invention relates to a device and method for dewiring compressed waste bales.

Prior Art

For recycling purposes, waste is collected separately by groups, such as paper, glass, packaging, etc. In waste sorting plants, waste is further separated by type of material. Packaging is thus separated into metal packaging (e.g. aluminium cans) and plastic packaging (e.g. PVC, PET, etc.). Once the materials have been separated, the waste is compressed to the smallest possible volume, wrapped with steel wire having a thickness of 3 to 6 mm in dedicated baling machines, and prepared for transport to waste processing plants. The wire is wrapped around the bale circumference in one or more mutually parallel first planes, so that four sides of the bale are wrapped with wire and two sides are free. Often the bales are also wrapped with wire in one or more mutually parallel second planes perpendicular to the first planes, so that four sides of the bale are wrapped with wire, while the two sides have wires placed at right angles to each other.

After the bales are transported to the recycling plant, individual bales are placed on a conveyor belt, where they first need to be dewired, as the steel wire would be an obstacle in all subsequent recycling operations. There are several dewiring ways. The first way is manual, where the worker cuts each wire manually and removes it. This operation is dangerous as the highly tensioned wire can heavily jolt the worker at the moment he cuts it and injure the worker. For this reason, several automated bale dewiring devices have been developed. Document US5406690A discloses a bale dewiring device having a blade which presses against the bale from above to cut the wires and then a sliding element with a groove mounted beneath the bale moves under the bale in a direction perpendicular to the wires, so that the wires fit into the grooves and are pulled out from beneath the bale. A disadvantage of the device is that it does not allow dewiring of the bales wrapped with wire in two directions.

Document US6986233B1 discloses a system for removing one or more wires wrapped around a bale. The system includes a frame, a bale receiving region defined by the frame and defining a longitudinal direction, an upper press plate mounted to the frame for vertically moving into contact with the bale to compress the bale, and side press plates movable in the longitudinal direction into contact with the bale to compress the bale. A rail is operably mounted to the upper plate for vertical movement therewith. A cutting assembly is mounted to the rail for movement along the rail for cutting the one or more wires. A winding assembly is operably mounted to the frame and includes a rotary winding element having a wire receiving region and a wire winding region for winding the cut wires to remove the wires from the bale. This system does not allow dewiring of the bales wrapped with wire in two directions, either.

Technical problem

The technical problem is how to provide a bale dewiring device and method that will allow the removal of steel wires of different thicknesses (from 3 to 6 mm in diameter), for different bale sizes (from 0.7 x 0.7 x 1 m to 1.4 x 1.4 x 2.5 m), for different types of baled materials (paper, plastics, metals, etc.) and for bales wrapped in one or two directions. Solution to the technical problem

The relative terms such as lower, upper, vertical, horizontal etc. are defined according to the orientation of the device in the operating position.

The technical problem is solved by a bale dewiring device comprising:

- a frame further comprising at least four vertical supports arranged so as to define between them a square bale receiving region and a plurality of horizontal supports connecting respective adjacent pairs of vertical supports,

- a first wire winder positioned at the first pair of vertical supports in the horizontal direction, wherein the first wire winder comprises a winder support, a pair of horizontal, mutually spaced rods fixedly engaged at one end in a first end section which can be driven in rotation by a first drive, and detachably engaged at the other end in a second end section which is pivotally arranged in the winder support arranged in a way to be detachable from the rods together with the second end section by means of a second drive, and a wire removal means which is capable of being moved linearly along the rods on the winder support by means of a third drive, an inner part of the wire removal means through which the rods are passed being pivotally arranged in an outer annular part of the wire removal means,

- a second wire winder positioned at the second pair of vertical supports adjacent to the first pair of the vertical supports, in the horizontal direction, the second wire winder being analogous in construction and arrangement to the first wire winder,

- a first wire gripper mounted at the first pair of vertical supports in the horizontal direction, wherein the first wire gripper comprises a gripper holder fixedly connected to the frame, at least one fixed plate provided with gripping teeth, a movable plate provided with gripping teeth which is linearly movable in the longitudinal direction of the gripper relative to the at least one fixed plate with gripper teeth by means of a fifth drive, wherein the plates with gripping teeth are movable linearly by means of a sixth drive in the direction of the bale to be dewired and backwards, the first wire gripper being arranged so that the gripping teeth of the at least one fixed plate and the moving plate can extend between the rods of the first wire winder,

- a second wire gripper mounted at the second pair of vertical supports and analogous in construction and arrangement to the first wire gripper,

- a first cutting means mounted at a third pair of vertical supports opposite the first pair of vertical supports in a horizontal direction, wherein the first cutting means comprises a first cutting means support fixedly connected to the frame, at least one fixed plate with cutting teeth, a movable plate with cutting teeth which is linearly movable in the longitudinal direction of the cutting means relative to the at least one fixed plate with cutting teeth by means of a seventh drive, the plates with cutting teeth being linearly movable in the direction of the bale to be dewired by means of an eighth drive and backwards,

- a second cutting means mounted at the fourth pair of vertical supports opposite the second pair of vertical supports, the second cutting means being analogous in construction and arrangement to the first cutting means; and

- a controller.

The invention further relates to a bale dewiring method comprising the following steps: a) providing said bale dewiring device, d) positioning the wired bale in the device such that the wires on the lateral sides of the bale run in a vertical direction, e) positioning the rods of the first and second wire winders such that they overlap in the vertical direction, f) linearly horizontally moving the first and second wire grippers and the first and second cutting means in the direction of the bale, such that the gripping teeth and the cutting teeth are at least partially engaged in the bale, g) linearly horizontally moving the movable plate with gripping teeth relative to the fixed plate(s) with gripping teeth of the gripper, such that the gripping teeth grip the wire, and linearly moving the movable plate with cutting teeth relative to the fixed plate(s) with cutting teeth, so that the cutting teeth cut the wires, h) linearly moving the first and second wire grippers in a direction away from the bale to pull the wire through the region between the rods of the first and second wire winders, i) linearly moving the first and second cutting means in a direction away from the bale, j) rotating the rods of the first and second wire winders by about 180°, k) linearly horizontally moving the support plate of the support table, l) linearly horizontally moving the movable plate with gripping teeth relative to the fixed plate(s) with gripping teeth, such that the gripping teeth release the wire, m) rotating the rods of the first and second wire winders such that the wire winds onto the rods, n) linearly moving the wire removal means of the first and second wire winders along the bars, o) moving the support of the first and second wire winders together with the second end section before the wire removal means of the first and second wire winders reaches the end position to release the ends of the rods from said second end section, and further linearly moving the wire removal means of the first and second wire winders along the rods to push the wire wound on the rods off the rods; p) linearly moving the wire removal means and the second end section of the first and second wire winders back to the initial position.

The advantage of the bale dewiring device and method of the invention is that steel wires of different thicknesses can be removed, for different bale sizes, for different types of baled materials and for bales wrapped in one or two directions.

Figure 1: Bale de wiring device Figure 2: Frame of the bale dewiring device

Figure 3: Wire winder with a movable support - top view

Figure 4: Wire winder with a movable support - bottom view

Figure 5: Wire gripper

Figure 6: Cutting means

Figure 7: Support table

Figure 8: Support wall - front view

Figure 9: Support wall without guides and drives - rear view

Figure 10: Bale dewiring device with two conveyor belts

Figure 11 : Wire winder with a pivotal support - top view

Figure 12: Wire winder with a pivotal support - bottom view

Figure 13: Wire gripper with two fixed plates

Figure 14: Cutting means with two fixed plates

Figure 15: Cutting means with cutting teeth with profiled segment inserts

Figure 16: Bale dewiring device with a conveyor belt for conveying waste wire from the device

Figure 17: Segment inserts

The invention is described in more detail hereinbelow.

The technical problem is solved by a bale dewiring device 100 comprising:

- a frame 10 further comprising at least four vertical supports 11, 12, 13, 14 arranged so as to define between them a square bale receiving region and a plurality of horizontal supports 15 connecting respective adjacent pairs of vertical supports,

- a first wire winder 20 positioned at the first pair of vertical supports 11, 12 in the horizontal direction, wherein the first wire winder 20 comprises a winder support 21, a pair of horizontal, mutually spaced rods 22 fixedly engaged at one end in a first end section 23 which can be driven in rotation by a first drive 24, and detachably engaged at the other end in a second end section 25 which is pivotally arranged in the winder support 21 arranged in a way to be detachable from the rods 22 together with the second end section 25 by means of a second drive 26, and a wire removal means 27 which is capable of being moved linearly along the rods 22 on the winder support by means of a third drive 28, an inner part 27a of the wire removal means through which the rods 22 are passed being pivotally arranged in an outer annular part 27b of the wire removal means,

- a second wire winder 20’ positioned at the second pair of vertical supports 11, 14 adjacent to the first pair of the vertical supports, in the horizontal direction, the second wire winder 20’ being analogous in construction and arrangement to the first wire winder 20,

- a first wire gripper 30 mounted at the first pair of vertical supports 11, 12 in the horizontal direction, wherein the first wire gripper comprises a gripper holder 31 fixedly connected to the frame, at least one fixed plate 32 provided with gripping teeth 32a, a movable plate 33 provided with gripping teeth 33a which is linearly movable in the longitudinal direction of the gripper relative to the at least one fixed plate 32 with gripper teeth by means of a fifth drive 34, wherein the plates with gripping teeth are movable linearly by means of a sixth drive 35 in the direction of the bale to be dewired and backwards, the first wire gripper being arranged so that the gripping teeth of the at least one fixed plate and the moving plate can extend between the rods 22 of the first wire winder,

- a second wire gripper 30’ mounted at the second pair of vertical supports 11, 14 and analogous in construction and arrangement to the first wire gripper,

- a first cutting means 40 mounted at a third pair of vertical supports 13, 14 opposite the first pair of vertical supports in a horizontal direction, wherein the first cutting means 40 comprises a first cutting means support 41 fixedly connected to the frame 10, at least one fixed plate 42 with cutting teeth 42a, a movable plate with cutting teeth 43 a which is linearly movable in the longitudinal direction of the cutting means relative to the at least one fixed plate with cutting teeth by means of a seventh drive 44, the plates with cutting teeth being linearly movable in the direction of the bale to be dewired by means of an eighth drive 45 and backwards,

- a second cutting means 40’ mounted at the fourth pair of vertical supports 12, 13 opposite the second pair of vertical supports, the second cutting means being analogous in construction and arrangement to the first cutting means; and

- a controller.

The tips of the teeth 32a, 33a of the first or second gripping means, respectively, and the tips 42a, 43a of the teeth of the first or second cutting means, respectively, may be formed conically to easily engage between the wires and into the bale.

The distal ends of the teeth 32a, 33a of the first or second gripper, respectively, may be formed by widening to improve the grip of the wire. This prevents the wire from being dislodged from the first or second gripper when the wire is pulled through the first or second wire winder, respectively.

According to a preferred embodiment, the first and second wire gripping means 30, 30' each comprise two fixed plates 32 with gripping teeth 32a and a movable plate 33 with gripping teeth 33a arranged between the fixed plates 32, and the first and second cutting means 40, 40’ each comprise two fixed plates 42 with cutting teeth 42a and a movable plate with cutting teeth 43a arranged between the fixed plates 42. If the gripper and the cutting means are formed by only one fixed and one movable plate, the gripping or cutting of the wire may be subject to shear forces which attempt to twist the wire, and this may cause the gripping or cutting teeth of one and the other plate to deform and spread. However, by using two fixed plates and one movable plate, the spreading and deformation of the gripping or cutting teeth of one plate and the other is prevented. Further preferably, the fixed plates are interconnected by a plurality of screws 36 with spacers interspaced between the fixed plates. In this way, the fixed plates are formed as a rigid housing to receive the movable plate and at the same time as a guide for the movable plate. The gripping and cutting teeth are preferably formed by segmented inserts 39. In the event of wear or damage to a single cutting tooth, this allows for quick replacement, as the entire plate assembly does not have to be dismantled. The screws securing the segmental insert to the tooth are removed, the insert is replaced with a new one and screwed back onto the tooth. The material of the segmented inserts is selected to have a higher hardness and also a higher toughness than the wire to be cut. Examples of suitable materials are: quenched or tempered steel, ceramics, vidia, etc. Preferably, the segment inserts in the gripping and cutting teeth are arranged in such a way that the segment inserts of each pair of the gripping teeth or cutting teeth in each position of the fixed and movable plates overlap at least partially. This ensures that the teeth do not get stuck. The gripping or cutting face of the segmented inserts is preferably profiled, which allows better gripping of the wire. The face may be profiled in the form of semicircular or triangular cut-outs, for instance. When one fixed and one movable plate of the cutting means are used, it is reasonable that the faces of the segmented inserts forming the cutting edge enclose an acute angle. When two fixed and one movable plate of the cutting means are used, it is reasonable that the faces of the segmented inserts of the fixed plates forming the cutting edge enclose an acute angle, while the faces of the segmented inserts of the movable plate enclose a right angle. The same applies to the gripper. It is recommended that the acute angle is selected in a range between 60° and 89°.

Figures 3 and 4 show a winder support 21, which is movable mounted on linear guides 29a which are fixed to the frame of the bale dewiring device. The linear displacement of the winder support 21 is achieved by means of an electromechanical cylinder 26 arranged in the direction of the linear guides. According to a second embodiment, as shown in Figures 11 and 12, the winder support 21 is fixedly connected to the bale dewiring device frame via a hinge 29b. A piston rod of the cylinder 26 is connected to the winder support 21 in such a way to pivot the latter around the hinge 29b. In this embodiment, the winder support 21 is separated from the rods 22, together with the second end section 25, by a circular arc motion.

The rods 22 may be formed as rods 22a having a circular cross-section. According to a preferred embodiment, the two rods 22 are formed as rods 22b having a crosssection in the form of an isosceles trapezoid. The advantage of this embodiment is that the rods of trapezoidal shape provide greater rigidity, while at the same time the edges of the trapezoid are slightly recessed into the wire, thus providing a better grip on the wire.

The bale dewiring device may further comprise:

- a horizontally movable support table 50 for supporting bales, comprising a table support 51 mounted on the frame at a pair of vertical supports, a support plate, linear support table guides connecting the table support and the support plate 52, and a ninth drive 53 for moving the support plate from the support position, in which the support plate is positioned in the region between the vertical supports of the frame supporting the bale to be dewired, to the retracted position in which the support plate is positioned in the region outside the vertical supports of the frame, and vice versa; and

- a first conveyor belt 70 arranged beneath the support table 50 and at a distance from it such that it can receive and transport the bale material once the bale is dewired and the support plate 52 of the support table 50 has been removed.

The bale dewiring device may further comprise:

- a horizontally movable support wall 60 comprising a support wall holder 61 mounted on the frame at a pair of vertical supports, an upper support plate 62, linear retaining wall guides 63 connecting the wall holder and the upper support plate, a tenth drive 64 for moving the upper support plate, a lower support plate 65 hinged to the upper support plate 62 and at least one spring 66 connected at one end to the upper support plate 62 and connected at the other end to the lower support plate 65.

The purpose of the horizontally movable supporting wall is to allow the bale receiving region to be adapted to a respective size of a bale to be dewired. If the bale to be dewired is of smaller dimensions, it may happen that when the bale is manipulated it tips over into the receiving region of the bale dewiring device and the orientation of the wires on the side walls of the bale is incorrect. However, by moving the support wall, the receiving region can be reduced and the bale can be prevented from tipping over. The function of the suspension between the lower and upper support plates is to absorb the impact of the bale on the support table when the bale is being manipulated into the bale receiving region. Information on the size of the bale to be dewired can be obtained using contactless distance measuring devices, such as a laser or optical distance sensor.

The bale dewiring device may further comprise a second conveyor belt 80 or an elevator for manipulating the bales into the receiving region of the device.

The bale dewiring device may further comprise protective sheets 90 to prevent unauthorised access to the moving parts of the device.

The bale dewiring device may further comprise a platform 91 for easier access to the device.

The bale dewiring device may further comprise a third conveyor belt 92 for conveying the wire removed from a bale from the device.

The first to tenth drives are selected from a group comprising: geared electric motor, electric motor, electro-hydraulic cylinder or actuator, electro -pneumatic cylinder, pneumatic cylinder, electromechanical cylinder and hydraulic cylinder. The linear guides are selected from a group comprising: sliding guides comprising guiding rails and sliding carriage, roller guides comprising guiding rails and roller bearing carriage, and spindle.

A transmission may be arranged between the drive and the linear guides, selected from a group comprising: gear transmission, chain transmission, toothed belt transmission and spindle transmission, or combinations thereof.

The combinations of a drive, a transmission and a guide are all within the scope of conventional design configurations. Figure 5 shows a drive of a gripper movable plate 32, which is provided with an electro -hydraulic cylinder, the piston of which is connected directly to the linearly guided gripper movable plate. The movement of the gripper towards/away from the bale can be achieved, as shown in Figure 5, by means of an electric motor with a reduction gear, on the drive shaft of which a sprocket 37a is mounted which, via a chain 37b, drives an axle 37c of a spindle 37d, which is connected simultaneously by a chain to the axle of a second spindle, so that a synchronous movement of the two ends of the gripper is achieved. The spindle housing is fixed to the device frame and a spindle nut 37e is fixed to the gripper plate assembly. Figure 13 shows the gripper drive 35 which is provided with an electric motor with a reduction gear driving a drive shaft 38a that is fixed on cantilevers and provided with two sprockets. The cantilevers are fixed to the frame of the bale dewiring device. Axles 38c that are provided with two sprockets are fixed to guide rails 38f which are fixed to the cantilever. The gripping plates are fixed to two carriages 38g which are guided on rails. Each sprocket on the axle is connected to a corresponding sprocket on the drive shaft by a chain 38d (shown schematically in the figure). The chain is fixed to the gripper plates using screws 38e.

The invention further relates to a bale dewiring method comprising the following steps: a) providing a bale dewiring device 100, d) positioning the wired bale in the device such that the wires on the lateral sides of the bale run in a vertical direction, e) positioning the rods 22 of the first and second wire winders such that they overlap in the vertical direction, f) linearly horizontally moving the first and second wire grippers 30, 30’ and the first and second cutting means 40, 40’ in the direction of the bale, such that the gripping teeth 32a, 33a and the cutting teeth 42a, 43a are at least partially engaged in the bale, g) linearly horizontally moving the movable plate 33 with gripping teeth relative to the fixed plate(s) 32 with gripping teeth of the gripper, such that the gripping teeth grip the wire, and linearly moving the movable plate with cutting teeth relative to the fixed plate(s) with cutting teeth, so that the cutting teeth cut the wires, h) linearly moving the first and second wire grippers 20, 20’ in a direction away from the bale to pull the wire through the region between the rods 22 of the first and second wire winders, i) linearly moving the first and second cutting means 40, 40’ in a direction away from the bale, j) rotating the rods 22 of the first and second wire winders by about 180°, k) linearly horizontally moving the support plate 52 of the support table 50, l) linearly horizontally moving the movable plate 33 with gripping teeth relative to the fixed plate(s) 32 with gripping teeth, such that the gripping teeth release the wire, m) rotating the rods 22 of the first and second wire winders such that the wire winds onto the rods, n) linearly moving the wire removal means 27 of the first and second wire winders along the bars, o) moving the support 21 of the first and second wire winders together with the second end section 25 before the wire removal means 27 of the first and second wire winders reaches the end position to release the ends of the rods from said second end section, and further linearly moving the wire removal means of the first and second wire winders along the rods to push the wire wound on the rods off the rods; р) linearly moving the wire removal means 27 and the second end section 25 of the first and second wire winders back to the initial position.

The reason why the wire removal means of the first and second wire winders starts to move linearly along the rods before the rod ends are released from said second end section of the first and second wire winders is that the wire removal means of the first and second wire winders provides better support to the rods and prevents possible twisting of the rods.

The method may further comprise the following two steps: b) after step a) and before step d) linear movement of the support table 50 to a support position in which the support plate is positioned in the area between the vertical supports of the support frame of the bale to be dewired, after step p) linear movement of the support table (50) to a retracted position in which the support plate is positioned in the area outside the vertical supports of the frame, r) transporting the bale material from the device.

The method may further comprise the following step: с) after step a) and before, after or simultaneously with step b), linear movement of the support wall 60 to limit the bale receiving region by adjusting the size of the receiving region to the size of the bale to be dewired.