AU2011317542B2

AU2011317542B2 - Adapter for screen elements

Info

Publication number: AU2011317542B2
Application number: AU2011317542A
Authority: AU
Inventors: Mike Bygrave
Original assignee: Metso Sweden AB
Current assignee: Metso Sweden AB
Priority date: 2010-10-22
Filing date: 2011-10-21
Publication date: 2015-03-26
Anticipated expiration: 2031-10-21
Also published as: CL2013001098A1; EP2444167B1; BR112013009790A2; WO2012052558A1; AU2011317542A1; EP2444167A1

Abstract

An attachment device for attaching screen elements to a frame (2) of a screening apparatus comprises a frame attachment portion (3) for attachment to the screen frame (2) and a screen attachment portion (6) for attachment of the screen elements. The frame attachment portion (3) comprises a first frame attachment section (4) and a second frame attachment section (5), each frame attachment section (4, 5) being arranged to be attached to a first frame section (2a) and a second frame section (2b), respectively. The frame sections (2a, 2b) form between them a frame angle (α) of less than 180°. The screen attachment portion (6) is curved such that screen elements attached to the screen attachment portion form a screen surface on which the frame angle (α) corresponds to two or more screen angles (β

Description

1 ADAPTER FOR SCREEN ELEMENTS Technical Field of the Invention The present invention relates to an attachment device for attaching screen elements to a frame of a screening apparatus, comprising a frame attachment portion for attachment to the screen frame and a screen attachment portion for 5 attachment of the screen elements. The present invention further relates to a screening apparatus comprising a screen frame, a plurality of screen elements, and at least one attachment device attaching said screen elements to said screen frame. 10 Background Art An example of a screen attachment device may be found in US-5,462,175, which discloses an attachment strip having spreading pins that lock into holes in a screen frame and having bolts for securing screen elements on the screen frame. In one embodiment, the attachment strip may be wedge-shaped in order to create 15 a stair-step screen deck. Attachment strips of this type may be used for attaching screen elements from one manufacturer to a screen frame from another manufacturer. Another example of a screen attachment device may be seen in WO 06/031176. 20 However, for some screening apparatus, there still remain problems. This is particularly the case for so-called "banana screens", in which the screen frame beams are mounted with an angle between them which is less than 1800, thereby forming an arcuate or banana-shaped screen deck. An example of a "banana screen" may be found in, e.g., WO 02/11908. Around the angle transition point, 25 where there is a change in inclination, the wear becomes particularly intense, thus necessitating more frequent replacement of screen elements. The reference to background art in this specification is not intended to, and should not be taken as, an acknowledgment, statement, suggestion or admission 2 that the referenced prior art forms part of the common general knowledge in Australia or in any other country. Summary of the Invention 5 It would be advantageous for at least some embodiments in accordance with the present invention to provide an attachment device for attachment of screen elements to the frame of a screening apparatus which is improved in comparison to prior art attachment devices, or which at least provides a useful alternative. 10 It would be advantageous for at least some embodiments in accordance with the present invention to provide an attachment device which makes it possible to reduce localised wear in connection with inclination changes on a screen deck. According to a first aspect there is provided an attachment device for attaching screen elements to a frame of a screening apparatus, comprising a 15 frame attachment portion for attachment to the screen frame and a screen attachment portion for attachment of the screen elements, wherein said frame attachment portion comprises a first frame attachment section and a second frame attachment section, each frame attachment section being arranged to be attached to a first frame section and a second frame section, respectively, said frame 20 sections forming between them a frame angle of less than 1800, and wherein said screen attachment portion is curved such that screen elements attached to said screen attachment portion form a screen surface on which said frame angle corresponds to two or more screen angles of less than 1800 and larger than said frame angle or which has a circular arc shape. 25 By splitting up the angle formed between the frame sections into at least two angles on the screen deck formed by the screen elements such an attachment device makes it possible to reduce the localised wear that occurs around an inclination change on the screen deck. The same effect is achieved by transforming the frame angle into a circular arc shape on the screen surface.

3 In an embodiment, the screen attachment portion has a circular arc shape. This is a simple way of ensuring that the screen surface gets a circular arc shape. In one embodiment, said screen attachment portion comprises at least a first screen attachment section, a second screen attachment section and a third 5 screen attachment section, each screen attachment section being arranged to be attached to a respective screen element, wherein a first and a second of said screen elements form between them a first screen angle and the second and a third screen element form between them a second screen angle, said screen angles being less than 1800 and larger than said frame angle. This is a convenient 10 way of dividing the frame angle into two or more larger screen angles on the screen surface. In one embodiment, the screen angles are equal. This makes it possible to make the attachment device mirror-symmetric. It is thereby easier to mount the attachment device on the frame, since it can be placed with either end on either 15 side of the inclination change on the frame without affecting the inclinations of the screen elements that are later attached to the attachment device. The frame attachment sections may each comprise a plurality of locking devices for locking onto the frame, the locking devices of said first frame attachment section being arranged in a first plane and the locking devices of said 20 second frame attachment section being arranged in a second plane, said first and second planes forming between them the frame angle. By having the frame attachment sections form between the same angle as the frame sections to which the attachment device is to be attached, the attachment device may be particularly simple in construction. 25 The locking devices may comprise spreading pins for locking into holes in said frame. Thereby, it is easy to attach the attachment device to the frame, the spreading pins being compressed while passing through the hole, and the attachment device is securely held in place when the spreading pins have spread again after passing through the hole in the frame.

4 In one embodiment, the first screen attachment section is arranged to be essentially parallel to said first frame section, said third screen attachment section is arranged to be essentially parallel to said second frame section, said second screen attachment section being arranged between said first and third screen 5 attachment sections, said first and second screen attachment sections forming between them said first screen angle and said second and third screen attachment sections forming between them said second screen angle. This arrangement makes it easy to construct an attachment device for each desired inclination of the screen elements. 10 The screen attachment sections may comprise a profiled strip adapted to engage an undercut groove on an underside of said screen elements. The screen elements may thereby easily, and securely be attached to the attachment device by simply pressing or hammering down the screen elements onto the profiled strip. According to a second aspect there is provided a screening apparatus 15 comprising a screen frame, a plurality of screen elements, and at least one attachment device in accordance with the first aspect, said attachment device attaching said screen elements to said screen frame. The screening apparatus of the second aspect may be varied with the features described above in connection with the first aspect and may provide corresponding advantages. 20 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 said element, device, component, means, step, etc., unless explicitly stated otherwise. 25 As used herein, the term "curved" is to be understood as not straight. Thus, a curved screen attachment portion may be of a shape which is, e.g. made up of straight portions forming an angle between them, i.e, with an angular bend, or arcuate, or more particularly a circle segment.

5 In the specification the term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition 5 also applies to variations on the term "comprising" such as "comprise" and ''comprises". Brief Description of the Drawings Embodiments will be described, by way of example only, with reference to the appended schematic drawings. 10 Fig. 1 is a side view of an attachment device attached to the upper side of a frame of a screening apparatus. Fig. 2 is cross-sectional perspective view of the attachment device and screen frame of Fig. 1. Fig. 3 is a partial perspective view of a screen element which may be 15 attached to a frame of a screening apparatus by means of the attachment device of Figs 1 and 2. Fig. 4 is a side view of an attachment device according to an alternative embodiment attached to the upper side of a frame of a screening apparatus. Fig. 5 is a perspective view of the attachment device of Fig. 4. 20 Fig. 6 is a perspective view of a screening deck incorporating the attachment device of Fig. 4. Detailed Description of Preferred Embodiments The attachment device or upgrade strip 1 in Fig. 1 is attached to a beam of 25 a screen frame 2. The beam is divided into a first beam portion 2a and a second beam portion 2b. The upgrade strip 1 has a frame attachment portion 3, by which the upgrade strip 1 is attached to the frame 2. The frame attachment portion 3 is divided into a first frame attachment section 4 and a second frame attachment 6 section 5, each in the form of a plurality of spreading pins 10. The spreading pins 10 of the first frame attachment section 4 are arranged in a first plane and the spreading pins 10 of the second frame attachment section 5 are arranged in a second plane. These first and second planes form between them an angle a of 5 less than 1800, such that the upgrade strip 1 may be attached to the frame 2 in which beam portions 2a, 2b form such an angle a which is less than 1800. Further, the upgrade strip 1 has a screen attachment portion 6 by which screen elements 12 (see Fig. 3) are attached to the upgrade strip 1, and hence, to the screen frame 2. The screen attachment portion 6 is divided into three screen 10 attachment sections 7, 8, 9. The first screen attachment section 7 is parallel to the first beam portion 2a and the third screen attachment section 9 is parallel to the second beam portion 2b. The second screen attachment portion 8 is arranged between the first and third screen attachment sections 7, 9 and forms with each of these an angle P1, p2, which is less than 1800, but which is larger than the angle a 15 between the frame portions 2a, 2b. The frame attachment sections 4, 5 have a plurality of locking devices in the form of spreading pins 10 for locking the upgrade strip 1 onto the frame 2. The screen attachment sections 7, 8, 9 take the form of profiled strips 11. When screen elements, such as the screen element 12 shown in Fig. 3, are 20 to be attached to the frame 2, the upgrade strip 1 is attached to the frame 2 by pressing or hammering the spreading pins 10 into holes (not shown) in the frame 2. Once the upgrade strip is in place, screen elements 12 are attached to the upgrade strip 1 by pressing or hammering the screen elements onto the upgrade strip 1, such that the profiled strips 11 of the upgrade strip 1 enter into undercut 25 grooves 13 on the underside of the screen elements 12. An alternative embodiment of the attachment device or upgrade strip is shown in Figs 4-6. Here, parts similar to the ones in the embodiment shown in Figs 1-3 are denoted by the same reference numbers, but with the addition of 100.

7 In the same way as with the upgrade strip 1 of Figs 1-3, the upgrade strip 101 of Fig. 4 has a frame attachment portion 103, by which the upgrade strip 101 is attached to the frame 102. The frame attachment portion 103 is divided into a first frame attachment section 104 and a second frame attachment section 105, 5 each in the form of a plurality of spreading pins 110. The spreading pins 110 of the first frame attachment section 104 are arranged in a first plane and the spreading pins 110 of the second frame attachment section 105 are arranged in a second plane. These first and second planes form between them an angle c of less than 1800, such that the upgrade strip 101 may be attached to the frame 102 in which 10 beam portions 102a, 102b form such an angle c which is less than 1800. Further, the upgrade strip 101 has a screen attachment portion 106 by which screen elements 112 are attached to the upgrade strip 101, and hence, to the screen frame 102. The screen attachment portion 6 is curved in a circular arc shape 116 such that the screen surface obtains a corresponding circular arc 15 shape 115. In order to be able to form such a circular arc shape 115, the screen elements 112 may be manufactured with the circular arc shape 115. Alternatively, the screen elements may be manufactured from a slightly flexible material, such that originally flat screen elements 112 may be bent to the desired circular arc shape 115. 20 The upgrade strip 101 is attached to the frame 102 in essentially the same manner as described above in connection with Figs 1-3 by means of locking devices 110. With the upgrade strip 101 an even better reduction of localised wear due to transition angles may be achieved, since the screen surface 114 may be formed 25 essentially without transition angles. In the example shown in Fig.1, the angle a formed by the beams of the frame is 1700 and the angles P1, P2 are 1750. Naturally, the upgrade strip of the invention may be adapted to other angles of the frame. The angle of the frame may also be split up into more than two angles between the screen elements. The 30 angles need not necessarily be equal.

8 In the examples described above, the upgrade strip is made in one part. However, the upgrade strip of the invention could also be made in separate parts, preferably two or three parts. If the upgrade strip is made up of two parts, these are advantageously formed as two essentially identical halves of the upgrade strip 5 shown in Fig. 1, each half comprising a respective one of the transitions of the angles p1, P2. The two halves could also have different angles of transition. If the upgrade strip is made up of three parts, a first part could be made to correspond to the leftmost portion of the upgrade strip 1 of Fig. 1, up until the transition angle p1, a second part could be made to correspond to the centre portion between the 10 transition angles p1i, P2, and a third part could be made to correspond to the rightmost portion of the upgrade strip 1 of Fig. 1. As with the one-part and two-part upgrade strip discussed above, the transition angles could be equal or different. The attachment sections may have other kinds of locking devices for locking the upgrade strip onto the frame. The locking devices are preferably 15 adapted to the kind of frame to which the upgrade strip and screen elements are to be attached. For instance, locking devices in the form of bolts and nuts may be used, although it is preferable to use locking devices that do not require tools. In the same way, the screen attachment sections may have other forms than the profiled strip shown in Fig. 2. Profiled strips with other shapes may be 20 used, adapted to the shape of an undercut groove on the underside of the screen elements to be attached. Other principles of attaching the screen elements to the screen frame are also feasible, for instance using profiled studs on the attachment device that lock into corresponding recesses on the underside of the screen elements. 25 The attachment devices are preferably made of stainless steel, but may also be made of elastomeric material, such as polyurethane. Other modifications of, and improvements to, the described embodiments may be incorporated without departing from the scope of the invention as claimed.

Claims

1. An attachment device for attaching screen elements to a frame of a screening apparatus, comprising a frame attachment portion for attachment to the 5 screen frame and a screen attachment portion for attachment of the screen elements, wherein said frame attachment portion comprises a first frame attachment section and a second frame attachment section, each frame attachment section being arranged to be attached to a first frame section and a second frame section, respectively, said frame sections forming between them a 10 frame angle of less than 1800, and wherein said screen attachment portion is curved such that screen elements attached to said screen attachment portion form a screen surface on which said frame angle corresponds to two or more screen angles of less than 1800 and larger than said frame angle or which has a circular arc shape 15

2. An attachment device as claimed in claim 1, wherein said screen attachment portion has a circular arc shape.

3. An attachment device as claimed in claim 1, wherein said screen 20 attachment portion comprises at least a first screen attachment section, a second screen attachment section and a third screen attachment section, each screen attachment section being arranged to be attached to a respective screen element, wherein a first and a second of said screen elements form between them a first screen angle and the second and a third screen element form between them a 25 second screen angle, said screen angles being less than 1800 and larger than said frame angle.

4. An attachment device as claimed in claim 1 or 3, wherein said screen angles are equal. 30

5. An attachment device as claimed in any one of the preceding claims, wherein said frame attachment sections each comprise a plurality of locking 10 devices for locking onto the frame, the locking devices of said first frame attachment section being arranged in a first plane and the locking devices of said second frame attachment section being arranged in a second plane, said first and second planes forming between them the frame angle. 5

6. An attachment device as claimed in claim 5, wherein said locking devices comprise spreading pins for locking into holes in said frame.

7. An attachment device as claimed in any one of claims 3-6, wherein said first 10 screen attachment section is arranged to be essentially parallel to said first frame section, said third screen attachment section is arranged to be essentially parallel to said second frame section, and wherein said second screen attachment section is arranged between said first and third screen attachment sections, said first and second screen attachment sections forming between them said first screen angle 15 and said second and third screen attachment sections forming between them said second screen angle.

8. An attachment device as claimed in any one of the preceding claims, wherein said screen attachment portion comprises a profiled strip adapted to 20 engage an undercut groove on an underside of said screen elements.

9. A screening apparatus comprising a screen frame, a plurality of screen elements, and at least one attachment device as claimed in any one of claims 1-8, said attachment device attaching said screen elements to said screen frame. 25

10. An attachment device, for attaching screen elements to a frame, substantially as described in the part of this specification entitled Detailed Description of Preferred Embodiments, with reference to the accompanying drawings. 30

11. A screening apparatus comprising at least one attachment device as claimed in claim 10.