EP2444167B1

EP2444167B1 - Adapter for screen elements

Info

Publication number: EP2444167B1
Application number: EP10188518A
Authority: EP
Inventors: Mike Bygrave
Original assignee: Metso Minerals Sweden AB
Current assignee: Metso Sweden AB
Priority date: 2010-10-22
Filing date: 2010-10-22
Publication date: 2013-03-20
Anticipated expiration: 2030-10-22
Also published as: BR112013009790A2; AU2011317542B2; CL2013001098A1; EP2444167A1; AU2011317542A1; WO2012052558A1

Description

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 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

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 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 or in US 5 248 043 in which an intermediate deformable frame structure is disclosed.
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 180°, 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, where there is a change in inclination, the wear becomes particularly intense, thus necessitating more frequent replacement of screen elements.

Summary of the Invention

An object of the invention is 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.
A particular object of the invention is to provide an attachment device which makes it possible to reduce localised wear in connection with inclination changes on a screen deck.
These objects are achieved, in part or in full, by an attachment device as claimed in claim 1. Preferred embodiments are defined in the dependent claims.
An attachment device according to the invention is characterised in that the 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 frame angle of less than 180°, and in that 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 180° and larger than said frame angle or which has a circular arc shape. 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.
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 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 180° and larger than said frame angle. This is a convenient 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 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 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.
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.
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 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.
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.
The above-mentioned objects are also achieved, in part or in full, by means of a screening apparatus according to the invention comprising a screen frame, a plurality of screen elements, and at least one attachment device as described above, said attachment device attaching said screen elements to said screen frame. The screening apparatus of the invention may be varied with the features described above in connection with the attachment device and has the same accompanying advantages.
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.
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.

Brief Description of the Drawings

The invention will be described in more detail with reference to the appended schematic drawings, which show an example of an embodiment of the invention.

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 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.
Fig. 6 is a perspective view of a screening deck incorporating the attachment device of Fig. 4.

Detailed Description of Preferred Embodiments of the Invention

The attachment device or upgrade strip 1 in Fig. 1 is attached to a beam of 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 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 α of less than 180°, such that the upgrade strip 1 may be attached to the frame 2 in which beam portions 2a, 2b form such an angle α which is less than 180°.
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 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 β₁, β₂, which is less than 180°, but which is larger than the angle α 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 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 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.
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, 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 α of less than 180°, such that the upgrade strip 101 may be attached to the frame 102 in which beam portions 102a, 102b form such an angle α which is less than 180°.
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 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.
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 essentially without transition angles.
In the example shown in Fig.1, the angle α formed by the beams of the frame is 170° and the angles β₁, β₂ are 175°. 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 angles need not necessarily be equal.
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 shown in Fig. 1, each half comprising a respective one of the transitions of the angles β₁, β₂. 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 β₁, a second part could be made to correspond to the centre portion between the transition angles β₁, β₂, 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 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 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.
The attachment devices are preferably made of stainless steel, but may also be made of elastomeric material, such as polyurethane.

Claims

An attachment device for attaching screen elements (12; 112) to a frame (2; 102) of a screening apparatus, comprising a frame attachment portion (3; 103) for attachment to the screen frame (2; 102) and a screen attachment portion (6; 106) for attachment of the screen elements (12; 112), characterised in that said frame attachment portion (3; 103) comprises a first frame attachment section (4; 104) and a second frame attachment section (5;105), each frame attachment section (4, 5; 104, 105) being arranged to be attached to a first frame section (2a; 102a) and a second frame section (2b; 102b), respectively, said frame sections (2a, 2b; 102a, 102b) forming between them a frame angle (α) of less than 180°, and in that said screen attachment portion (6; 106) is curved such that screen elements (12; 112) attached to said screen attachment portion (6; 106) form a screen surface (14; 114) on which said frame angle (α) corresponds to two or more screen angles (β₁, β₂) of less than 180° and larger than said frame angle (α) or which has a circular arc shape (115).
An attachment device as claimed in claim 1, wherein said screen attachment portion (106) has a circular arc shape (116).
An attachment device as claimed in claim 1, wherein said screen attachment portion (6) comprises at least a first screen attachment section (7), a second screen attachment section (8) and a third screen attachment section (9), each screen attachment section (7, 8, 9) being arranged to be attached to a respective screen element (12), wherein a first and a second of said screen elements (12) form between them a first screen angle (β₁) and the second and a third screen element (12) form between them a second screen angle (β₂), said screen angles (β₁, β₂) being less than 180° and larger than said frame angle (α).
An attachment device as claimed in claim 1 or 3, wherein said screen angles (β₁, β₂) are equal.
An attachment device as claimed in any one of the preceding claims, wherein said frame attachment sections (4, 5; 104, 105) each comprise a plurality of locking devices (10; 110) for locking onto the frame (2; 102), the locking devices (10; 110) of said first frame attachment section (4; 104) being arranged in a first plane and the locking devices (10; 110) of said second frame attachment section (5; 105) being arranged in a second plane, said first and second planes forming between them the frame angle (α).
An attachment device as claimed in claim 5, wherein said locking devices comprise spreading pins (10; 110) for locking into holes in said frame (2; 102).
An attachment device as claimed in any one of claims 3-6, wherein said first screen attachment section (7) is arranged to be essentially parallel to said first frame section (2a), said third screen attachment section (9) is arranged to be essentially parallel to said second frame section (2b), and wherein said second screen attachment section (8) is arranged between said first and third screen attachment sections (7, 9), said first and second screen attachment sections (7, 8) forming between them said first screen angle (β₁) and said second and third screen attachment sections (8, 9) forming between them said second screen angle (β₂).
An attachment device as claimed in any one of the preceding claims, wherein said screen attachment portion (6; 106) comprises a profiled strip (11; 111) adapted to engage an undercut groove (13; 113) on an underside of said screen elements (12; 112).
A screening apparatus comprising a screen frame (2; 102), a plurality of screen elements (12; 112), and at least one attachment device (1; 101) as claimed in any one of claims 1-8, said attachment device (1; 101) attaching said screen elements (12; 112) to said screen frame (2; 102).