Sieving device for separating bulk materials, especially stones and soils

Abstract

A sieve for sorting and separating bulk material, comprising a sieve frame (1) with a plurality of bars (2) forming sieve meshes, wherein the bars (2) are mounted, wherein at least some of the bars (2) are mounted such that a play fit is formed, resulting in a loose mounting and the bars (2) are freely rotatable about their longitudinal axes and / or movable in the direction of their longitudinal axes and / or transversely thereto to a limited extent, wherein the bars (2) are supported by a frame (3), comprising supports (4, 5, 6) containing bearings (7, 8, 9) for the loose mounting of the bars (2), and wherein the supports (4, 5, 6) are located at the end regions of the bars (2) or between them, characterized in that at least some of the bearings (7, 8, 9) are spring-loaded.

Description

[0001] The invention relates to a screening device according to the preamble of claim 1, in particular for separating and sorting bulk material for the construction, processing and recycling industries.

[0002] Known screening devices comprise a grate formed from a plurality of bars, which define a screening opening depending on the spacing of the bars. The bars are arranged at regular or irregular intervals, allowing the opening cross-section of the grate to be varied. The grate may comprise bars that run in only one direction and are arranged parallel to one another, or may comprise additional transverse bars that are inclined relative to the first-mentioned bars, for example, running perpendicular to them.

[0003] The purpose of screening devices of this type is to separate and sort bulk material, which contains coarse and fine components, by allowing the fine components to pass through the openings of the grate, while the coarse components remain on the grate. The screening of bulk material is advantageously carried out by applying vibrations to the screening device or grate, which also improves screening efficiency.

[0004] DE 20 2018 102 352 U1 describes a screening bucket for earthmoving equipment with one or more struts that are adjustable or removable to vary the opening cross-section of the grate.

[0005] DE 20 2014 006 020 U1 describes a screening bucket for earthmoving equipment. To intensify the screening process, the screening bucket is vibrated by a motor with an eccentric gear.

[0006] FI 119683 B describes a stationary screening device.

[0007] DE 11 44 ​​212 B discloses three variants in which the rods can be mounted.

[0008] Due to the bulk material composition, for example, coarse, heavy paving stones combined with fine soil, sand, or pebbles, deformation and wear on the bars occur over time. This makes removing the bars difficult or impossible, as a cross-section of the bars at the deformed point does not fit through the cross-section of a storage opening.

[0009] The invention is based on the object of designing a screening device according to the preamble of claim 1 in such a way that the service life, in particular that of the screen grate and the bars, is extended, that the bars can be easily and quickly replaced and that the screening efficiency is improved with less equipment expenditure.

[0010] This object is achieved with a screening device according to claim 1.

[0011] The decisive feature of the invention consists of the following: The rods and / or the rod-supporting bearings are designed in such a way that at least some of the rods can rotate about their longitudinal axis and / or have limited movement in the direction of their longitudinal axes and / or transversely thereto. The free rotation of each individual rod about its own longitudinal axis is crucial here. The bearing in question has such a large clearance in relation to the diameter of the end of the rod supported by the bearing that the rod can deflect transversely to its longitudinal axis during operation. This can therefore be described as a swaying bearing. The rod may also be movable in the direction of its longitudinal axis or transversely thereto. The individual rod thus has every conceivable degree of freedom.

[0012] When the screening device is in operation, bulk material usually slides over the bars of the screen grate. This is because the screen grate is inclined during operation so that the bulk material slides from an upper feed point to a lower feed point. Since the bars are loosely mounted and can therefore rotate freely, they are set in rotation by the bulk material. Since the bulk material particles vary in size and weight, the impact of the particles on the bars also varies in force. This means that each bar moves up and down. Important: The up and down movement is achieved by the provision of elastic bearings. This means the following: If a bulk material particle impacts a bar, the spring assigned to the bearing is compressed according to the weight of the impacting particle. Since the following particle is or may be of lower weight, the spring is relieved again, causing the affected bar to move upwards.The sorting process is thus intensified.

[0013] In contrast to conventional screening devices, the bars rotate during the screening process as they are carried along by the bulk material. These rotations can be continuous due to the varying nature of the bulk material. Generally, the rotation is rather jerky. Unlike the bars of conventional screening devices, the impact of the bulk material occurs across the entire surface of the bar, not just a single area. Wear per unit area is therefore lower than with state-of-the-art technology, resulting in a longer service life for the bar.

[0014] The intensified screening process achieved according to the invention makes it possible to dispense with special vibrators. The design of the screening device itself generates the necessary vibration. This makes the screening device according to the invention more cost-effective to manufacture than competing devices.

[0015] Finally, even if the individual rod is deformed or excessively worn, it is really easy to pull it out of its bearings, as the mounting holes of the bearings are wide, so that even with severely deformed or bent rods there are no problems.

[0016] The fact that the screening efficiency of a screening device according to the invention is increased compared to the prior art follows from the above.

[0017] The fit between the rod and a bore in which the rods are accommodated is designed as a radial clearance fit. This clearance fit allows the rods to rotate even without ball bearings. In addition, the rods can perform two-dimensional movements in the radial direction of the bore, for example, a reciprocating and / or circular movement.

[0018] The bars can be supported in two supports, one at each end of the bars. The bars have bearings for supporting the bars. The bar ends and the corresponding bearings form a clearance fit.

[0019] The clearance fits allow for easy replacement of deformed rods without the risk of jamming. The clearance fits are designed so that the rods have a significantly smaller cross-section than the openings, for example, a diameter ratio of 60 mm to 72 mm. Generally, the diameter ratio can be between 1:1.1 and 1:3.

[0020] Preferably, the bars are cylindrical. However, it can be provided that the cross-section of the bars is circular only in the area of ​​the support points, and that the bars in the remaining areas are non-circular in cross-section, e.g., hexagonal.

[0021] The shape of the supports can also vary. For example, in a side view, they can be straight, parabolic, and / or curved. The shape of the screen grate, in a side view, also essentially corresponds to the respective contour of the supports.

[0022] Additionally, it is conceivable to install cross bars with an oval, circular, or rectangular cross-section, extending along the screen grate perpendicular to the bars. The cross bars reinforce the bars against sagging and simultaneously define one dimension of the screen grate's opening cross-section.

[0023] The described screening device can be used or applied, in particular, in a grating, sorting, or screening bucket for excavators or construction machinery. Said bucket has a substantially bulbous base that forms the screening grid, is bounded laterally by two supports, and has a bucket on a front side. A fastening system is arranged on a rear edge for attaching the bucket to an arm of the excavator.

[0024] Metal such as cast iron or stainless steel is conceivable as the material for the sieve and the spoon.

[0025] The invention is explained in more detail with reference to the drawing, which shows the following in detail: Fig. 1 a perspective view of a spoon with a screening device; Fig. 2 a sectional view of a bearing showing a clearance fit.

[0026] The Fig. The bucket shown in Figure 1 can be part of an excavator or a construction machine. The bucket comprises a screen grate 1 with a plurality of bars 2, which in turn form screen meshes. The bars 2 are arranged within a frame 3. In the region of the ends of the bars 2, the frame 3 comprises a lateral support 4, 5 and a central support 6. All supports have bearings 7, 8, 9, namely the two lateral (outer) supports 4, 5 contain bearings 7 and 8 respectively, and the central support 6 contains bearing 9. The central support 6 can be omitted. The two outer supports 4, 5 can also be omitted, so that only the central support 6 remains.

[0027] The bars 2 are generally made of solid, special-grade steel. They can also be designed as sleeves, especially for large diameters and thus high section moduli.

[0028] Fig. Figure 2 reveals an essential feature of the invention: The end region of a rod 2 is mounted in a bearing 9 of one outer support 5. This is a clearance fit, with the inside diameter of the bearing 9 being extremely large relative to the diameter of the rod 2.

[0029] As shown schematically, the bearing is designed such that rod 2 can rotate freely about its own longitudinal axis - see A, that rod 2 can continue to move perpendicular to its longitudinal axis - see B, and that it can finally move in the direction of its longitudinal axis - see C.

[0030] The bearings 9 are covered by a cap 10. This can be opened so that rod 2 can be guided out through the bearing 9. In the illustration according to Fig. 1, cap 10 is designed such that it extends over several bearings. List of reference symbols 1 sieve grate 2 bars 3 frames 4, 5 side supports 6 middle carrier 7, 8, 9 camps 10 Cap as a safety device

Claims

[1] Screening device for sorting and separating bulk material, comprising a screen grate (1) with a plurality of bars (2) which form screen meshes with one another, wherein the bars (2) are mounted, wherein at least some of the bars (2) are mounted in such a way that a loose fit is formed, so that a slack-free mounting is created and the bars (2) are freely rotatable about their longitudinal axes and / or movable in the direction of their longitudinal axes and / or transversely thereto to a limited extent, wherein the bars (2) are carried by a frame (3) comprising supports (4, 5, 6) which contain bearings (7, 8, 9) for the slack-free mounting of the bars (2), and wherein the supports (4, 5, 6) are located at the end regions of the bars (2) or between them, characterized by that at least some of the bearings (7, 8, 9) are spring-loaded. [2] Screening device according to claim 1, characterized by that the clearance of the bearings (7, 8, 9) is at least 1.05 times the diameter of the respective rod (2). [3] Screening device according to claim 1 or 2, characterized by that this is a grating, sorting or screening bucket of an excavator or a construction vehicle. [4] Screening device according to one of claims 1 to 3, characterized by that the bearings (7, 8, 9) contain through holes in the supports (4, 5, 6), that the clear width of a through hole is greater than the diameter of the relevant rod (2), and that a safety device (10) is provided to limit the displacement of the rod (2) in its longitudinal direction. [5] Screening device according to one of claims 1 to 4, characterized by that at least one rod (2) has a cross-sectional shape deviating from the round cross-sectional shape at least over a length section outside the region of its bearings (7, 8, 9). [6] Screening device according to one of claims 1 to 5, characterized by that the screen grate (1) has a curved shape in the direction of movement of the bulk material.

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