EP3429836A1

EP3429836A1 - Method for pressing and strapping bales of material in a baler, and such a baler

Info

Publication number: EP3429836A1
Application number: EP16894718.2A
Authority: EP
Inventors: Anders Larsson; Mats Andersson
Original assignee: Presona AB
Current assignee: Presona AB
Priority date: 2016-03-17
Filing date: 2016-11-14
Publication date: 2019-01-23
Also published as: WO2017160199A1; SE539873C2; EP3429836A4; SE1650364A1

Abstract

The invention relates to a method for pressing and strapping bales (2) of material in a baler (1). The method comprises the steps of feeding the material into the baler (1) in a first direction, compressing the material into a bale (2) by means of a main press (7), transporting the bale (2) of material in a second direction to engage with a continuous strap (8) which in an initial position crosses the second direction in the baler (1), and moving the strap (8) in relation to the bale (2) to substantially enclose the bale (2). The method is characterised by the step of friction welding the strap (8) together to completely enclose the bale (2). The invention is also related to a baler (1) for pressing and strapping bales (2) of material.

Description

METHOD FOR PRESSING AND STRAPPING BALES OF MATERIAL IN A

BALER, AND SUCH A BALER

Technical field

The invention relates to a method for pressing and strapping bales of material in a baler. The invention also relates to a baler for pressing and strapping bales of material.

Background art

Strapping systems are often used to bind and secure various types of materials after they have been compressed and formed into a bale. In many strapping applications, individual bales of materials are bound with metal wire immediately after the bale has been created, the metal wire being secured, as needed, along the length of the bale in order to maintain the bale in formed and compressed state. Although metal wiring adequately performs its function of securing the baled material and preventing the bulk of the bale from falling apart, the material cost for the metal wire is relatively high. Additionally, if metal wire is used to bind bales of garbage or solid waste used as refuse derived fuel (RDF) it must be removed in a subsequent step in the process, since the wire would survive the incineration process intact.

There are, however, methods available today in which plastic strapping is used instead of a metal wire. US 2013/0180416 discloses a system and method for applying plastic strapping to bales of material. A strap track assembly comprises a frame, a track, and a flap assembly. The frame is sized and configured to permit a bale of material to pass there through. The track is coupled to and positioned along an inner surface of the frame, with the track sized and configured to house a length of strapping material therein. The flap assembly is operatively connected to a portion of track positioned along a lower portion of the frame, with the flap assembly including a first flap in selective contact with a second flap. The first flap may be constructed of a metallic material, and the second strap may be constructed of an elastomeric material such as rubber. A debris cover may be operatively connected to a front surface of the frame, with a portion of the debris cover positioned above at least a portion of the track so as to inhibit individual pieces of baled material from contacting the flap assembly and/or the track. Individual plates may be operatively connected to and extend away from an exit portion of an associated baler.

A drawback with the system and method described above is that the strapping process is quite complicated and the interconnection of the strap ends often requires some kind of a heat generating process.

Summary of the invention

It is an object of the present invention to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination and solve at least the above mentioned problem.

According to a first aspect, these and other objects are achieved in full, or at least in part, by a method for pressing and strapping bales of material in a baler. The method comprises the steps of feeding the material into the baler in a first direction, compressing the material into a bale by means of a main press, transporting the bale of material in a second direction to engage with a continuous strap which in an initial position crosses the second direction in the baler, and moving the strap in relation to the bale to substantially enclose the bale. The method is characterised by the step of friction welding the strap together to completely enclose the bale. By using friction welding in order to close the strap around the bale the generation of heat is very low and thus the risk of igniting any surrounding material will be eliminated. Further, the continuous strap is made of a plastic material which makes the strap cheap and combustible. The friction welding of the strap is preferably performed in an overlapping manner which creates a stable and rigid point of attachment.

The step of friction welding may comprise welding the strap together at a first welding point and at a second welding point. This way, the strap may be cut by means of a cutting element between the first welding point and the second welding point, such that the enclosed bale of material is detached from the continuous strap which in turn moves back to the initial position. Alternately, the strap is cut first and thereafter welded at the first welding point to secure the strap around the bale and at the second welding point to again form the continuous strap after the cut. The first welding point and the second welding point may be provided simultaneously. Thereafter, the process may be repeated time after time without any manual contribution from service personnel.

The step of transporting the bale may comprise pushing the bale by means of the main press in the second direction into engagement with the continuous strap so that it at least partially encloses the bale. Thus, the main press has a dual function. The material is compressed within the press chamber by moving the main press in the second direction to engage with the material and compress the same into a bale. Simultaneously, the bale is transported in the second direction by moving the main press to engage with the continuous strap.

The step of moving the strap may comprise hooking the strap by means of a strap element and pulling the strap in relation to the bale to substantially enclose said bale. In one exemplary embodiment, the strap element is constituted by a needle provided with a hook on one of its outer ends. When the bale of material has been pushed in the second direction by the main press to engage with the strap, the needle is lowered in the first direction to hook the strap and pull it upwards so that the strap substantially surrounds the bale of material. Thereafter, the strap may be cut and welded in order to release the bale of material from the continuous strap which in turn moves back to said initial position. From here, the entire process can be repeated.

According to a second aspect of the invention, the objects are achieved in full, or at least in part, by a baler for pressing and strapping bales of material. The baler comprises an inlet for receiving the material in a first direction into a press chamber in which the material is to be compressed, a main press movably arranged in connection with the press chamber and adapted to compress the material into a bale and to transport the bale of material in a second direction, a continuous strap crossing the second direction and adapted to engage with the bale of material when transported in the second direction, and a strap element movably arranged in connection with the press chamber and adapted to move the strap in relation to the bale to substantially enclose the bale. The baler is characterised in that it further comprises a friction welding unit adapted to friction weld the strap together to completely enclose the bale. The advantages described above in connection with the method for pressing and strapping of bales of material in a baler also apply for the baler itself.

In more detail, the main press may comprise a pressing element arranged on a cylinder that is movable in the second direction between an idle mode and a working mode. In the idle mode, the main press is still. Here, either other parts of the baler are in operation or the baler is simply not in use. In the working mode, the main press is conducting the step of compressing the material in the press chamber into a bale together with the step of transporting the bale of material in the second direction.

The pressing element of the main press may further comprise a through hole through which the strap element is adapted to move to reach the strap. In other words, the through hole is provided to avoid a conflict between the main press and the needle during the strapping process of the bale of material.

The baler may further comprise a cutting element adapted to cut the strap, such that the enclosed bale of material is detached from the continuous strap which in turn moves back to its initial position.

The friction welding unit may comprise a movable cutting tool and a fixed welding tool, wherein the movable cutting tool is movable in the second direction. This way, the movable cutting tool may assist the strap element in enclosing the bale of material with the strap. When the strap element has pulled the strap upwards in relation to the bale, the movable cutting tool may be moved to retrieve the strap and move the same in the second direction in order to substantially enclose the bale.

The baler may further comprise first roller and a second roller arranged outside of the press chamber and between which the strap extends. Further, the baler may comprise at least one guiding roller adapted to guide the strap between the first roller and a second roller. The first and second roller may easily be removed and replaced when the strap is used up. The baler may further comprise a pre-press adapted to pre-press the material into the press chamber. In more detail, the pre-press may be pivotably arranged in connection with the press chamber and adapted to pivot about a shaft between an idle mode and a working mode.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [element, device, component, means, step, etc.]" are to be interpreted openly as referring to at least one instance of the element, device, component, means, step, etc., unless explicitly stated otherwise.

The method may be used independently from the baler described in the present application. In other words, the method may be used in

connection with any suitable type of baler.

It should also be noted that the first and second direction described herein may be varied in any suitable way.

Brief description of the drawings

The above objects, as well as additional objects, features and advantages of the present invention, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, when taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a perspective view of a baler according to one aspect of the present invention.

Fig. 2a-2e are side views of the baler in Fig. 1 performing method steps according to another aspect of the invention.

Fig. 3a-3i are side views of a friction welding unit when performing the steps of cutting and welding a continuous strap in the baler.

Detailed description of preferred embodiments of the invention

Fig. 1 illustrates one exemplary embodiment of a baler 1 for pressing and strapping bales 2 of material. The baler 1 comprises an inlet 3 for receiving the material in a first direction into a press chamber 4 of the baler 1 in which the material is to be compressed. The inlet 3 is in direct

communication with the press chamber 4. In this specific embodiment, the first direction is a vertical direction in relation to the baler 1 . This way, the material to be processed in the baler 1 can be transported by means of a conveyor (not shown) to the inlet 3 and from there by gravity into the press chamber 4.

The baler 1 further comprises a pre-press 5 that is pivotably arranged in connection with the press chamber 4 via a shaft 6. The pre-press 5 can thus pivot between an idle mode and a working mode. When the pre-press is in the idle mode (Fig. 2a), the material is allowed into the press chamber 4 via the inlet 3. When the pre-press 5 is in the working mode (Fig. 2b), the prepress 5 will help pressing the material into the press chamber 4 while simultaneously closing the inlet 3 so that no additional material can enter into the press chamber 4. From here, the compression phase of pressing the material into a bale 2 can be initiated (Fig. 2b). For this purpose, the baler 1 is equipped with a main press 7 movably arranged in connection with the press chamber 4. The main press 7 has the function of compressing the material into a bale 2 and, simultaneously, transporting the bale 2 in a second direction. In this specific embodiment, the second direction is a horizontal direction in relation to the baler 1 . Thus, in this embodiment, the second direction is perpendicular to the first direction. The main press 7 comprises a pressing element 14 arranged on a cylinder 15 that is movable in the second direction between an idle mode and a working mode. In the idle mode, the main press 7 is still and in its initial position. Here, other parts of the baler are in operation or the baler 1 is simply not in use. In the working mode, the main press 7 is conducting the step of compressing the material in the press chamber 4 into a bale 2 and simultaneously the step of transporting the bale 2 of material in the second direction.

The baler 1 further comprises a continuous strap 8 that extends between a first roller 9 and a second roller 10 and crosses the second direction in the baler 1 . The first roller 9 and the second roller 10 are arranged outside of the press chamber 4. In this specific embodiment, the baler 1 also comprises two guiding rollers 1 1 arranged in the bottom section of the baler 1 which are adapted to guide the strap 8 between said first roller 9 and a second roller 10. With this configuration, the bale 2 will automatically engage with the continuous strap 8 when it is transported in the second direction by means of the main press 7 so that the bale 2 is partly enclosed by the strap 8. Naturally, the position and number of guiding rollers 1 1 may be varied based on design and function of the baler 1 . This also applies for the first and second rollers 9, 10.

A strap element 12 is movably arranged in connection with the press chamber 4. The strap element 12 is constituted by a needle with a hook at one of its outer ends. When the bale 2 has been transported in the second direction by the main press 7 to engage with the strap 8, the needle is lowered (Fig. 2c) in the first direction to hook the strap 8 and pull it upwards (Fig. 2d) so that the strap 8 substantially surrounds the entire bale 2 of material. From here, the final step of the strapping process can be initiated. In this specific, embodiment, the pressing element 14 of the main press 7 comprises a through hole 16 through which the strap element 12 is adapted to move when reaching for the strap 8 in order to avoid a collision between the pressing element 14 and the strap element 12. In one embodiment, the through hole has an elongate cross-section. The through hole 16 may extend in the second direction such that it is open to a side of the pressing element 14. This makes it possible for the main press 7 to exert pressure on the bale 2 during the entire strapping process.

In order to perform the final step of the strapping process, the baler 1 comprises a friction welding unit 13. When the continuous strap 8 has been arranged to enclose the entire bale 2, as described above, it is held, cut and welded by the friction welding unit 13 so that the enclosed bale 2 of material is detached from the continuous strap 8 which in turn moves back to its initial position (Fig. 2e). It should be noted that the main press 7 also acts to maintain the bale of material in the right position during this final step. From here, the entire pressing and strapping process can be repeated.

Fig. 3a-3i illustrate one preferred embodiment of the friction welding unit 13 of the baler 1 and how it is used. Here, the friction welding unit 13 comprises a movable cutting tool 21 and a fixed welding tool 24. The fixed welding tool 24 comprises a movable portion 18 on which a first weld head 19 and a second weld head 20 are arranged, a movable upper holding element

22 and a movable lower holding element 23. The movable cutting tool 21 includes the cutting element 17.

In Fig. 3a, the initial position of the friction welding unit 13 is illustrated.

Here, one portion of the continuous strap 8 has just been pulled up by the strap element 12 and another portion of the strap 8 has been put into place by the movable cutting tool 21 of the friction welding unit 13 so that the bale 2 of material is enclosed. The strap 8 is now in position to be welded together.

In a first step, the upper and the lower holding elements 22, 23 are moved towards each other in a vertical direction in order to clamp the continuous strap 8 in four different clamping points C1 -C4.

Now, the continuous strap 8 is cut by means of the cutting element 17 in a first point (Fig. 3c).

From here, at least a portion of the movable cutting tool 21 is moved in a horizontal direction towards the movable portion 18 of the friction welding unit 13 (Fig. 3d). Here, the cut ends of the strap are folded by means of the movement of the movable portion 18 in the second direction.

In this position, the continuous strap 8 is cut by means of the cutting element 17 in a second point (Fig. 3e).

In the following steps, the movable portion 18 of the friction welding unit 13 is moved in the horizontal direction towards the movable cutting tool 21 (Fig. 3f). Here, the other cut ends of the strap are folded by means of the movement of the movable cutting tool 21 . Simultaneously the movable cutting tool 21 is moved back to its initial position so that the four cut ends of the continuous strap can be welded together by means of the first and second weld heads 19, 20 (Fig. 3g). The friction welding of the straps 8 is normally conducted on the upper side of the bale 2, preferably in the middle of the bale 2 and in the second direction in relation to the bale 2.

In a final step, the upper holding element 22, the lower holding element

23 and the movable portion 18 of the friction welding unit 13 are moved back to their initial position (Fig. 3h). Now, the enclosed bale 2 of material has been detached from the continuous strap 8 which in turn has been moved back to its initial position (Fig. 3i).

It is understood that other variations in the present invention are contemplated and in some instances, some features of the invention can be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly in a manner consistent with the scope of the invention.

For instance, the size, shape and number of the components in the baler may be varied. Also, these components may be moved in any suitable way. The cutting element is for example preferably moved by means of hydraulics. However, other possibilities are naturally also possible, such as by means of air or electricity.

The number and position of the weld heads may be varied in any suitable way. In one embodiment, there are five friction welding units, five strap elements and five through holes in the main press.

In one preferred embodiment, there are five friction welding units arranged at a first angle in the baler and five friction welding units arranged at a second angle in the baler, wherein the first angle is displaced 90 degrees from the second angle. Each friction welding unit comprises a cutting tool and a welding tool having two weld heads. This way, the straps may be arranged on the bale in an intersecting manner.

The size and shape of the strap may also vary. In one preferred embodiment, the strap has a width of 16 mm and a thickness of 0,8 mm. Also, the strapping around the bale of material may be arranged in any suitable way. The amount of separate straps and the pattern they form together on the bale of material may thus be varied.

The movable holding elements may be connected to a motor which makes them vibrate. They may also comprise a thorny surface. It should be noted that during the welding process it is either the movable holding elements that vibrate while the weld heads are kept still, or the weld heads vibrate while the movable holding elements are kept still. The baler may be a sheer baler. In this case, there is no prepress present in the baler. Instead, a knife is used, which cuts off the superfluous material above the main press.

Claims

1 . A method for pressing and strapping bales (2) of material in a baler (1 ), comprising the steps of

feeding said material into said baler (1 ) in a first direction, compressing said material into a bale (2) by means of a main press (7),

transporting said bale (2) of material in a second direction to engage with a continuous strap (8) which in an initial position crosses said second direction in said baler (1 ), and

moving said strap (8) in relation to said bale (2) to substantially enclose said bale (2),

characterised by the step of friction welding said strap (8) together to completely enclose said bale (2).

2. The method according to claim 1 , wherein the step of friction welding comprises welding said strap (8) together at a first welding point and at a second welding point.

3. The method according to claim 2, further comprising the step of cutting said strap (8) by means of a cutting element (17) between said first welding point and said second welding point, such that said enclosed bale (2) of material is detached from said continuous strap (8) which in turn moves back to said initial position.

4. The method according to any one of the preceding claims, wherein the step of transporting said bale (2) comprises pushing said bale (2) by means of said main press (7) in said second direction into said continuous strap (8) so that it at least partially encloses said bale (2).

5. The method according to any one of the preceding claims, wherein said friction welding of said strap (8) is performed in an overlapping manner.

6. The method according to any one of the preceding claims, wherein the step of moving said strap (8) comprises hooking said strap (8) by means of a strap element (12) and pulling said strap (8) in relation to said bale (2) to substantially enclose said bale (2).

7. A baler (1 ) for pressing and strapping bales (2) of material, comprising

an inlet (3) for receiving said material in a first direction into a press chamber (4) in which said material is to be compressed,

a main press (7) movably arranged in connection with said press chamber (4) and adapted to compress said material into a bale (2) and to transport said bale (2) of material in a second direction,

a continuous strap (8) crossing said second direction and adapted to engage with a said bale (2) of material when transported in said second direction, and

a strap element (12) movably arranged in connection with said press chamber (4) and adapted to move said strap (8) in relation to said bale (2) to substantially enclose said bale (2),

characterised in that said baler (1 ) further comprises a friction welding unit adapted to friction weld said strap (8) together to completely enclose said bale (2).

8. The baler (1 ) according to claim 7, wherein said main press (7) comprises a pressing element (14) arranged on a cylinder (15) that is movable in said second direction between an idle mode and a working mode.

9. The baler (1 ) according to claim 7 or 8, wherein said pressing element (14) of said main press (7) comprises a through hole (16) through which said strap element (12) is adapted to move to reach said strap (8).

10. The baler (1 ) according to any one of the claims 7-9, further comprising a cutting element (17) adapted to cut said strap (8), such that said enclosed bale (2) of material is detached from said continuous strap (8) which in turn moves back to its initial position.

1 1 . The baler (1 ) according to any one of the claims 7-10, wherein said friction welding unit (13) comprises a movable cutting tool (21 ) and a fixed welding tool (24), said movable cutting tool (21 ) being movable in said second direction.

12. The baler (1 ) according to any one of the claims 7-1 1 , further comprising a first roller (9) and a second roller (10) arranged outside of said press chamber (4) and between which said strap (8) extends.

13. The baler (1 ) according to claim 12, further comprising at least one guiding roller (1 1 ) adapted to guide said strap (8) between said first roller (9) and said second roller (10).

14. The baler (1 ) according to any one of the claims 7-13, further comprising a pre-press (5) adapted to pre-press said material into said press chamber (4).

15. The baler (1 ) according to claim 14, wherein said

pre-press (5) is pivotably arranged in connection with said press chamber (4) and adapted to pivot about a shaft (6) between an idle mode and a working mode.