Screen tensioner for tensioning a screen coating

Abstract

A screen tensioner (40) for tensioning a screen lining (20) in a screening machine (10), wherein the screen tensioner (40) has a rod- or profile-like tensioning section (41) which has a fastening section (46) at each of its two longitudinal ends. The tensioning section (41) has a first tensioning projection (42) forming a first tensioning edge (42.1) on a first tensioning side and a second tensioning projection (43) forming a second tensioning edge (43.1) on an opposite second tensioning side, wherein the first tensioning edge (42.1) and the second tensioning edge (43.1) extend between the two fastening sections (46), the first tensioning edge (42.1) forms a first and the second tensioning edge (43.1) a second tensioning contour, and the first and second tensioning contours have different geometries.This provides a user with a way to easily tension different types of screen linings using a screen tensioner (40).

Description

[0001] The invention relates to a screen tensioner for tensioning a screen lining in a screening machine, wherein the screen tensioner has a rod-like or profile-like tensioning section which has a fastening section in the region of its two longitudinal ends.

[0002] The invention further relates to a screening machine with a screening tensioner.

[0003] DE 25 01 750 A discloses a screening machine with a screen box. Three screen panels are arranged one above the other. These screen panels are designed as grid bases with a bevel at their longitudinal ends. The bevels are bent from the top side of the screen panel to the bottom side. The bevels have a V-shaped cross-section. Screen tensioners, which are in the form of bars, engage in these bevels. The screen tensioner has a clamping projection on one clamping side, which forms a clamping edge. This clamping edge rests against the bottom of the bevel. At the longitudinal ends, the screen tensioners have fastening sections on which clamping elements act to tension the screen panel in the screen box.

[0004] When the screen tensioner is tensioned in this known device, the tension is uneven across the length of the screen tensioner. Accordingly, certain screen areas are subjected to greater pre-tension than neighboring screen areas. The varying tension leads to vibration behavior of the screen lining, which results in premature failure before the maximum service life of the screen lining is reached.

[0005] EP 0 238 455 A2 discloses a screening machine in which a screen panel is pre-tensioned with a screen tensioner in the form of a hollow profile. The screen tensioner has a molded-on clamping projection that forms a clamping edge.

[0006] This problem becomes even more acute when the user needs to install different types of screen media. Heavy-duty screen media require greater pre-tensioning than less heavy-duty screen media. Therefore, different screen tensioners must be available for different types of screen media. The user must then ensure that the correct screen tensioner is assigned to the corresponding screen media.

[0007] The object of the invention is to provide a user with the possibility of easily tensioning different types of screen coverings.

[0008] This object is achieved in that the clamping section of the screen tensioner has a first clamping projection in the region of a first clamping side, which forms a first clamping edge, and a second clamping projection on an opposite second clamping side, which forms a second clamping edge, that the first clamping edge and the second clamping edge extend between the two fastening sections, and that the first clamping edge forms a first and the second clamping edge forms a second clamping contour, and that the first and the second clamping contour have different geometries.

[0009] Because the screen clamp has two clamping edges, it can be used to clamp either edge into the screen panel being mounted. The clamping edges have different geometric shapes and are therefore designed for a specific screen panel. This allows the user to clamp two different screen panels in one screening device without having to change the clamp. The same clamp can be used, preferably in reverse, in two different mounting positions. This significantly simplifies screening machine maintenance.

[0010] According to the invention, one of the two clamping edges can be convex with a curvature extending between the two fastening sections, and the other clamping edge can be convex or concave with a curvature extending between the two fastening sections, or the other clamping edge can run in a straight line between the two fastening sections. If one clamping edge is convex and the other clamping edge is concave, it is advantageous if the contours followed by the two clamping edges differ from one another, preferably with the amount of elevation being different on both sides.

[0011] The curvature of the convex clamping edge of one clamping projection can be designed for a corresponding screen lining in order to clamp it in the screen box with the most uniform tension possible. When the screen lining is tensioned, the clamping edge with the furthest protruding area initially comes into contact with the associated fastening edge of the screen lining and tensions it there. As the screen tensioner is further tensioned, it deforms elastically, with the remaining areas of the clamping edge gradually coming into contact with the screen lining and tensioning it there. As a result, uniform tension is achieved across the entire width of the screen lining. This takes into account the knowledge that evenly tensioned screen linings have a longer service life and that inherent properties of the screen lining, such as self-cleaning, are supported.

[0012] If the second clamping edge is also convex, the degree of curvature can be designed to suit the corresponding screen lining in order to ensure that it is evenly applied.

[0013] If the second clamping edge is concave, this type of screen tensioner is suitable for screen media that require greater tension on two sides. These sides therefore come into contact with the concave geometry of the screen tensioner first.

[0014] If the second clamping edge is straight, the screen tensioner can be used on the straight edge for screen media that requires only a low level of screen tension. The second clamping edge is therefore ideal for light, delicate screen media, for example. These require less pre-tensioning. Due to the lower pre-tensioning force, a strongly curved clamping edge is not elastically deformed to the same extent, so that the outer areas of the light screen media do not make contact with the clamping edge and remain untensioned.

[0015] According to the invention, it can be provided that the clamping contours of the first clamping edge and the second clamping edge each have contour end sections in the region of their ends facing the fastening sections and a contour center between the contour end sections, such that when the clamping edge is projected into the central transverse plane (Q), the contour center of at least one of the clamping edges is offset with a maximum camber in or against the clamping direction relative to the contour end sections. It can be seen, for example, that the clamping edge is convexly or concavely curved, the amount of the camber being determined by the size of the recess if the clamping edge is concavely curved. If the clamping edge is convexly curved, the amount of the camber is the outwardly projecting projection of the clamping contour.According to a first variant of the invention, it can be provided that the amount of elevation of the first clamping edge differs from the elevation of the second clamping edge. In this way, two different clamping contours can be easily achieved. The clamping contours of the two clamping edges can be both convex or both concave, or one clamping edge can be convex and the other concave.

[0016] Preferably, however, the projection of one tensioning edge into the central transverse plane may also form a camber, while the projection of the other tensioning edge into the central transverse plane may form a straight line. Accordingly, one tensioning edge may be convex or concave, and the other straight.

[0017] If a convex or concave geometry is used for the clamping edge, the height (H) can preferably be less than or equal to 25 mm. Such screen clamps are suitable for use in screening machines used in conjunction with rock crushers or crushers for processing mineral materials. The maximum length of the screen clamp is preferably less than 1800 mm.

[0018] According to the invention, the clamping section can have a top side and a bottom side, and the screen tensioner can be designed, at least in the region of its clamping section, symmetrically to the central transverse plane extending between the top side and the bottom side. This screen tensioner is easy to install and has a compact design.

[0019] If the first and / or second clamping edge is provided with a rounded section running between the top and bottom of the clamping section, the stress peaks transferred to the screen lining are avoided or reduced.

[0020] According to a variant of the invention, assembly is made easier in that at least one of the fastening sections has at least one identification mark which is assigned to the first and / or the second clamping side, wherein the identification mark is preferably designed as a recess and more preferably is incorporated into the longitudinal end of the fastening section.

[0021] A possible variant of the invention can be such that the convex or concave clamping edge is circular or elliptical, or composed of multiple contour sections. This allows the clamping edge to be individually adapted to a screen lining. Preferably, the clamping edge follows a continuously differentiable function in the direction between the two fastening sections in order to achieve a tension-optimized structure.

[0022] The object of the invention is also achieved with a screening machine having a screening device which has a screening lining, wherein a screening tensioner according to one of claims 1 to 8 acts on the screening lining.

[0023] In this case, it can be provided in particular that the screen lining has a fastening edge on at least one of its longitudinal ends, which is designed in the form of an angled portion, and that the screen tensioner engages in the angled portion with one of its clamping projections.

[0024] The invention is explained in more detail below with reference to embodiments shown in the drawings.

[0025] They show: Figure 1a screening machine in side view, Figure 2a schematic detailed representation of a screening deck of the screening machine according to Figure 1 , Figure 3 in perspective partial representation a clamping device for a screen lining of the screening machine according to Figure 1 , Figure 4 in plan view and in partial representation a screen tensioner for the screening machine according to Figure 1 in association with a screen lining and in horizontal section, Figure 5 the representation according to Figure 4in an expanded view and Figure 6 shows a further embodiment of the invention, in which a screen box of the screening machine according to Figure 1 is shown in a schematic sectional view through a sieve lining.

[0026] Figure 1 shows a screening machine 10 according to the invention. This screening machine 10 is designed as a mobile screening machine. It is also conceivable that the invention could be used in a stationary screening machine.

[0027] The screening machine 10 has a chassis 11, which is supported by carriages 11.1 to enable the screening machine to be moved. Preferably, the screening machine 10 has a feed hopper 12. Material to be screened can be fed into the feed hopper 12 using a wheel loader.

[0028] The feed hopper 12 has a transport device, for example a vibrating chute, a conveyor belt, a feed belt, or a hopper discharge belt, by means of which the fed material can be conveyed to a feed belt 13. The feed belt 13 can be designed as a continuously rotating conveyor belt. The feed belt 13 conveys the material to be screened to a screening device having a screen box 60.

[0029] The screening device serves to separate at least two fractions from the supplied material. For this purpose, the screening device has at least one screen lining 20, as shown in Figure 2 shows.

[0030] Figure 1 further illustrates that the screen box 60 has side walls 61 which run in the longitudinal direction of the screen.

[0031] The screen box 60 is mounted to a stationary screen box support 64 by means of spring elements 63. A drive 65 can cause the screen box 60 to vibrate in order to screen the material.

[0032] The screening device is assigned at least one discharge belt 14.1, 14.2 or at least one fine-grain or stockpile belt 15. In the present embodiment, two discharge belts 14.1, 14.2 and one fine-grain or stockpile belt 15 are used. Accordingly, two screen linings 20 are installed in the screening device.

[0033] The material to be screened is fed onto the upper screen plate 20. The material that passes through the upper screen plate 20 passes onto the screen plate 20 below. Material that does not pass through the upper screen plate 20 passes onto one of the two discharge belts 14.1, 14.2. The material that does not pass through the second screen plate 20 passes onto the second discharge belt 14.1, 14.2. The material that passes through both screen plates 20 in the form of fine-grained material passes onto the fine-grain or stockpile belt 15. The two discharge belts 14.1, 14.2 and the fine-grain or stockpile belt 15 each convey the grain fractions fed to them to stockpiles 16.

[0034] Figure 2shows a schematic representation of a section of the screening device. As the illustration shows, support elements 30 are installed in the screen box 60, which support the screen lining 20. The support elements 30 have a mounting foot 32 with which they are fixed in place in the screen box 60. Opposite the mounting foot 32, replaceable damping elements 31 are mounted on one side of the support elements 30. The damping elements 31 support the screen lining 20 in the area of ​​the screen underside 22.

[0035] The support elements 30 can be arranged and aligned with their damping elements 31 in such a way that the screen lining 20 resting on the damping elements 31 forms an arcuate contour in the longitudinal direction of the screen, as Figure 2 shows.

[0036] The Figure 2The left-hand support element 30 has a holder attachment 33 at its end facing away from the fastening foot 32. The screen lining 20 is held replaceably on the holder attachment 33 by a fastening edge 23.

[0037] The screen lining 20 is designed as a flat element and has a screen upper side 21 opposite the screen lower side 22. The fastening edge 23 may be bent from an end section 23.1 of the screen lining 20 to form an angled portion 23.2. The retaining projection 33 engages this angled portion 23.2.

[0038] At the end facing away from the fastening edge 23, the screen lining 20 has another fastening edge 24, which is essentially structurally identical to the fastening edge 23. Accordingly, a bend 24.2 is bent from the screen lining 20 at the opposite end section 24.1.

[0039] The screen lining 20 must be positioned in the screen box 60 in the longitudinal direction (i.e. in Figure 2from left to right). For this purpose, a screen tensioner 40 is used. The Figures 3 and 5 illustrate that the screen tensioner 40 is essentially rectangular in cross-section. The screen tensioner 40 can therefore have a rod-shaped geometry.

[0040] The screen tensioner 40 has a central tensioning section 41 which extends between two end fastening sections 46.

[0041] The clamping section 41 has clamping projections 42, 43 on its opposite longitudinal sides. The first clamping projection 42 has a first clamping edge 42.1. The second clamping projection 43 has a second clamping edge 43.1.

[0042] The first clamping edge 42.1 is convexly curved between the two fastening sections 46, such as Figure 4 illustrated. Figure 4shows a horizontal section through the central transverse plane MQ of the screen tensioner 40. The central transverse plane MQ and thus the cutting plane according to Figure 4 is in Figure 3 marked.

[0043] Evidenced Figure 4 The first clamping edge 42.1 forms a clamping contour. This clamping contour has contour end sections 49.1 at its longitudinal ends and a contour center 49.2 centrally between the contour end sections 49.1. In the clamping direction, which is Figure 4 From right to left, the projection of the first clamping edge 42.1 into the central transverse plane MQ has a maximum camber H in the region of the contour center 49.2. This maximum camber H results from the fact that the contour center 49.2 is offset in the clamping direction relative to the contour end sections 49.1 due to the convex curvature. Preferably, the camber H is less than 25 mm.

[0044] The second clamping edge 43.1, which is opposite the first clamping edge 42.1, also forms a clamping contour. This clamping contour again forms contour end sections 49.1 at opposite ends, which face the fastening sections 46. A contour center 49.2 is formed centrally between the contour end sections 49.1.

[0045] In the present embodiment, the projection of the second clamping edge 43.1 into the central transverse plane MQ runs straight between the two fastening sections 46, as Figure 4 However, it is also conceivable that the second clamping edge 43.1 is convexly curved and has a maximum camber that preferably deviates from the maximum camber H of the first clamping edge 42.1.

[0046] It is also conceivable that the second clamping edge 43.1 forms a concave contour. In this case, a negative camber H results in the contour center 49.2. Preferably, the magnitude of the two cambers H of the two clamping edges 42.1, 43.1 differs from each other.

[0047] In other words, different clamping contours are realized on the screen tensioner 40 at the two clamping edges 42.1, 43.1.

[0048] As the illustrations further show, it is preferably the case that the screen tensioner 40 is constructed symmetrically to the central transverse plane MQ.

[0049] In the embodiment shown, the screen tensioner 40 engages with its first clamping projection 42 in the Figure 2shown right-hand bend 24.2. The screen tensioner 40 rests with its first clamping edge 42.1 on the bottom section 42.3 below the screen underside 22, resulting from the bend 24.2. Thus, the clamping projection 42 is at least partially enclosed between the screen underside 22 and the bend 24.2.

[0050] The screen tensioner 40 engages on opposite sides with its fastening sections 46 through passages 62 in the associated side walls 61 of the screen box 60, as Figure 3 . Accordingly, the fastening sections 46 protrude on the outside beyond the side walls 61 of the screen box 60. Clamping devices 50 are arranged in the area of ​​the passages 62 of the screen box 60, with which the screen tensioner 40 can be adjusted in the clamping direction along the central transverse plane MQ.

[0051] The clamping devices 50 each have a stationary support bearing 56, which is preferably firmly connected to the side wall 61, for example welded.

[0052] The support bearing 56 can be designed such that it has a holder 57 to which at least one bearing piece 56.1 is connected, preferably integrally formed. By means of the two bearing pieces 56.1 and the holder 57, the support bearing 56 can be stably connected to the associated side wall 61. The clamping device 50 further comprises a clamping piece 52, by means of which the screen tensioner 40 is positively engaged in order to displace it in the clamping direction. In this case, legs 51, 53 can be connected, preferably integrally formed, to the clamping piece 52 on opposite sides.

[0053] Between the legs 51, 53 there is a receptacle 54 for the screen tensioner 40. The leg 53 engages over the top and the leg 51 over the bottom of the screen tensioner 40, so that the screen tensioner 40 is prevented from deflecting in these directions when it is tensioned.

[0054] To adjust the clamping piece 52 in the clamping direction, at least one clamping screw 58 is used, by means of which the clamping piece 52 can be continuously adjusted. The clamping screw 58 rests on the holder 57. The continuous adjustment of the clamping piece 52 can be achieved via a threaded connection.

[0055] In the present embodiment, each of the legs 51, 53 has a threaded receptacle 55. The holder 57 has two passages through which the clamping screws 58 are inserted and screwed into the threaded receptacles 55.

[0056] The Figures 4 and 5show an assembly position in which the screen clamp 40 is in an unclamped position. If the clamping screws 58 of the two clamping devices 50 are now tightened, the first clamping edge 42.1 hits the base section 24.3 in the area of ​​its contour center 49.2 with its maximum elevation H (see Figure 4 ) of the bend 42.1. If the clamping screws 58 are now tightened further, the screen lining 20 is tensioned, starting from the contour center 49.2. This results in a counterforce of the screen lining 20, which acts on the screen tensioner 40. Due to this counterforce, the screen tensioner 40 is bent so that the first clamping edge 42.1 continuously rests against the base section 24.3 towards the two contour end sections 49.1. Thus, the clamping force is successively applied to the screen lining 20. The convexly curved contour of the first clamping edge 42.1 thus ensures uniform tensioning of the screen lining 20.

[0057] When the clamping devices 50 are tightened, the clamping piece 52 is displaced in the clamping direction. This ensures that the fastening section 46 is Figure 3 is displaced from left to right along the slot-shaped passage 62.

[0058] Once a sufficiently uniform tension has been generated in the screen lining 20, the assembly process is complete. The uniform tension can be estimated by performing a sound test at individual points on the screen lining 20. For this purpose, the screen lining 20 is struck at various points. The resulting sound can be used to determine the tension level.

[0059] Disassembly of the screen lining 20 is carried out in the reverse order. First, loosen the clamping screw 58, then slide the screen tensioner 40 in the bushings 62 until it disengages from the angled portion 24.2. The screen lining 20 can then be lifted upwards and moved in the opposite direction to the clamping direction, so that the angled portion 23.2 disengages from the retaining projection 33 (see Figure 2 ). The screen lining 20 can then be lifted out of the screen box 60 and replaced with a new screen lining 20.

[0060] If the second screen lining 20 is not identical in construction to the first screen lining 20 and requires a different, in particular less, pre-tension than the previously installed screen lining 20, the screen tensioner 40 can be adapted to this second screen lining 20. For this purpose, it only needs to be rotated so that the second clamping edge 42.1 engages with the associated angled portion 24.2 of this screen lining 20. The screen tensioner 40 can then be clamped to the new screen lining 20 in the same manner as explained above.

[0061] In other words, the screen tensioner 40 can be used to optimally tension two different screen linings 20.

[0062] To facilitate the correct assignment of the desired clamping edge 42.1, 43.1 to the respective screen lining 20, an identification mark 48 can be provided in the area of ​​at least one fastening section 46. The identification mark 48 is in Figure 4 shown by way of example. Preferably, the identification marking 48 is incorporated into the longitudinal end of the fastening section 48.

Claims

1. Screen tensioner (40) for tensioning a screen lining (20) in a screening machine (10), wherein the screen tensioner (40) has a rod-like or profile-like tensioning section (41) which has a fastening section (46) in the region of its two longitudinal ends, characterized in that the clamping section (41) has a first clamping projection (42) in the region of a first clamping side, which forms a first clamping edge (42.1) and has a second clamping projection (43) on an opposite second clamping side, which forms a second clamping edge (43.1), that the first clamping edge (42.1) and the second clamping edge (43.1) extend between the two fastening sections (46), that the first clamping edge (42.1) forms a first and the second clamping edge (43.1) forms a second clamping contour and that the first and the second clamping contour have different geometries.

2. Screen tensioner according to claim 1, characterized in thatone of the two clamping edges (42.1, 43.1) is convex with a curvature extending between the two fastening sections (46), and the other clamping edge (43.1, 42.1) is convex or concave with a curvature extending between the two fastening sections (46), or that the other clamping edge (43.1, 42.1) runs in a straight line between the two fastening sections (46).

3. Screen tensioner according to claim 1 or 2, characterized in thatthe clamping contours of the first clamping edge (42.1) and the second clamping edge (43.1) each have contour end sections (49.1) in the region of their ends facing the fastening sections (46) and a contour center (49.2) between the contour end sections (49.1), that when the clamping edge (42.1, 43.1) is projected into the central transverse plane (Q), the contour center (49.2) of at least one of the clamping edges (42.1, 43.1) is offset with respect to the contour end sections (49.1) in or against the clamping direction with a maximum camber (H), and that the amount of the camber (H) of the first clamping edge (42) differs from the camber (H) of the second clamping edge (43), or that the projection of one clamping edge (42.1, 43.1) into the central transverse plane (MQ) has a camber (H) and the projection the other tensioning edge (42.1, 43.1) forms a straight line in the central transverse plane (MQ).

4. Screen tensioner according to claim 3, characterized in thatthe amount of camber (H) is less than or equal to 25mm.

5. Screen tensioner according to one of claims 1 to 4, characterized in that the clamping section (41) has an upper side (44) and a lower side (45) and that the screen tensioner (40) is designed, at least in the region of its clamping section (41), symmetrically to the central transverse plane (MQ) extending between the upper side (44) and the lower side (45).

6. Screen tensioner according to one of claims 1 to 5, characterized in that the first and / or the second clamping edge (42, 43) have a rounded portion extending between the top and bottom of the clamping section (41).

7. Screen tensioner according to one of claims 1 to 6, characterized in thatat least one of the fastening sections (46) has at least one identification mark (48) which is assigned to the first and / or the second clamping side, wherein the identification mark (48) is preferably designed as a recess and more preferably is incorporated into the longitudinal end of the fastening section (46).

8. Screen tensioner according to one of claims 1 to 7, characterized in that the convex or concave clamping edge (42.1, 43.1) is circular or elliptical or is composed of several contour sections, and / or that the clamping edge (42.1, 43.1) follows a continuously differentiable function in the direction between the two fastening sections (46).

9. Screening machine (10) with a screening device having a screen lining (20), wherein a screen tensioner (40) according to one of claims 1 to 8 acts on the screen lining (20).

10. Screening machine (10) according to claim 9, characterized in thatthe screen lining (20) has a fastening edge (23, 24) on at least one of its longitudinal ends, which is designed in the form of an angled portion (23.2, 24.2), and that the screen tensioner (40) engages with one of its clamping projections (42, 43) in the angled portion (23.2, 24.2).

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