DE2443925A1 - Vibration sieve used in ore mining - with the sieves receiving an oscillation movement from a vibrator - Google Patents

Abstract

Vibration sieve with an installation to insert the material to be classified into the processing element which is located on frame supports fitted with dampers and receives an oscillation movement from a vibrator. The processing element (4) consists of at least one pair (22) of one part and hole-free plates (6). These pairs of irons are positioned on supports (5) at an angle to each other so that their lower edges (7) are located at a height sufficient to provide a gap (8) for the passage of a proportion of classified material. The plates (6) are arranged on the supports in such a way that they can swing in a vertical plane in order that the angle between the plates can be altered as required.

Description

V13RATIONAL SCREEN The present invention relates to recesses, which are used in ore mining to pre-classify lumpy mineral resources, ; nsbesondece on vibrating sieves.

It is known a vibrating screen which is a feed device for the goods to be classified, a conveyor for the classified goods, a frame with supports and dampers on which the working organ is located, which the The goods to be classified are divided into individual fractions and contain a vibrator which gives the working body a swinging movement through which the material is broken down into fractions is subdivided and moved along the working organ (see, for example, copyright certificate He. 70792 of the USSR).

The working organ of such a sieve consists of a box with fastened in it over its entire width and at a certain distance from each other, rigid metal grate bars. The sieve box is on the sieve frame or directly on it the foundation by means of supports with dampers made of helical or leaf springs exist, put on. An unbalance vibrator is placed on the sieve box, the is set in motion by an electric motor via a V-belt drive. Of the The unbalance vibrator gives the box a circular oscillating motion.

The presence of stiff and heavy grate bars in the box, of supports on which these grate bars are attached and an unbalance vibrator is the reason for the heavy weight of the reciprocating screen part and consequently for the creation of large dynamic loads, which on the dampers and the Foundation are transferred. To prevent the destruction of structures, on which the sieves must be put on, foundations with great mass and significant Dimensions are built, which is associated with significant capital outlays.

In addition, when classifying the material, it is necessary from this Good to separate fractions of a certain grain class.

With the existing vibrating screen designs, however, it is impossible to regulate the distance between the grate bars.

If this is necessary, however, the entire working body must be changed, which is associated with a great loss of time and consequently also with additional material costs is.

It is the aim of the present invention to overcome the disadvantages mentioned to eliminate.

The present invention is based on the object of providing a vibrating screen which, as a result of the perfection of its working organ, has a simple construction and a low weight, and is reliable and high-performance.

The problem posed is achieved in that, in the case of vibrating sieves, the one device for feeding the material to be classified into the working organ possesses, which is located on the supports of the frame, which are provided with dampers and receives an oscillating motion from a vibrator to move the material to be classified into To subdivide fractions and this one device for conveying the fractions to feed classified goods, t with this working organ in the direction of the latter Device is inclined, according to the invention, the working organ at least from a pair consists of one-piece and hole-free sheets, the sheets of this pair on supports lie at an angle to each other and - between their lower edges, which in lie at a height, there is a gap for the passage of a fraction of classified property.

The execution of the working body in the form of two one-piece and perforated sheet metal allows the weight of the working organ and accordingly To reduce the back and forth swinging sieve mass, since only in the swinging movement these sheets participate, which in turn reduces the power consumption of the electric motor of the vibrator is reduced.

As a result of the reduction in the reciprocating mass of the sieve the dynamic loads by which the dampers are stressed are reduced and as a result thereof, the construction of these dampers is simplified and it it becomes possible to dispense with special foundations or substructures with a large mass. In addition, through the use of one-piece and hole-free sheet metal as a working organ the simple construction of the latter and its operational reliability. the smooth surface of the one-piece and hole-free sheets as well as their position with relative Inclination towards each other favor a rapid advance of the goods on them and guarantee that all the goods to be classified get into the gap between the sheets, whereby a high separation factor increased one when dividing the material into fractions and Work) performance can be ensured.

Furthermore, the invention is characterized in that the metal sheets are arranged relative to one another on the supports in such a way that the gap width increases in the direction of the inclination of the work organ. Such an arrangement of the sheets makes it possible to subdivide the material to be classified into several fractions with different grain sizes, without swinging back and forth. the masses and the Sieve size 5 'to enlarge.

The invention is also characterized in that the sheets so are arranged on the Auzflagern that they are pivoted in the vertical plane can to change the angle of inclination between the sheets. This is how it becomes possible to divide the material into several fractions without changing the sieve dimensions to increase in plan with a reduction in the screen masses swinging back and forth.

The invention is also characterized in that at least one of the supports for pivoting the plates consists of two hingedly connected parts, a plate being arranged on one part and a sector with a series of openings being provided, while the other part is on the frame and has a bolt which can be pushed into one of the sector openings.

Such a structural design of the supports makes it possible to reduce the manufacturing and assembly costs of the vibrating screen. Also guaranteed they move the entire material to be classified across the gap independently of its physical-mechanical properties by changing the angle of inclination of the sheets and the elimination "through the gap" of a certain fraction The invention is further characterized in that the resting on the frame Part of the support has a spindle, while running a threaded hole in the frame is, in which the spindle is slidable around in this way the mentioned part to move the support on the frame and thereby the gap width between to change the sheets.

This makes it possible to adjust the gap width before beginning of the sieving operation to regulate a certain through the gap of the working organ To separate the fraction of the goods to be classified, reducing the number of vibrating sieves, the elimination of certain fractions from the to classifying Well required is significantly reduced.

The invention is also characterized in that additional pairs of sheets are arranged under a pair of one-piece and hole-free sheets, in each of them the sheets are mounted at an angle to each other and at such a distance that between their lower edges There is a gap, the width of which is smaller than the gap width of the previous pair for each 'lying pair, while the gaps of all pairs form a continuous and tapering passage from top to bottom for the advancement of the goods along this passage, whereby at the same time from the goods on the sheet metal pairs this corresponding fractions are eliminated. This makes it possible to divide the material into several fractions without increasing the dimensions of the vibrating sieve while reducing the back and forth swinging sieve masses.

The invention is also characterized in that at the bottom of the sheet metal stops are provided, which interact with those on the supports executed stops are available to move the sheets on these supports to avoid. Such a sheet metal arrangement on the support enables the To simplify construction of the working organ significantly and quickly the one Replace trays with others without dismantling the whole vibrating screen, thereby significantly extending its service life.

The invention is also characterized in that on the sheets the vibrators are attached, while the dampers are between the stops of the sheet metal and the support are arranged. Equipping each sheet with a single vibrator allows the most effective vibration regime (perturbation force, frequency and amplitude the vibrations) for the sheets depending on the physical-mechanical To choose properties of the good.

Due to the arrangement of the dampers between the stops on the metal sheets and the support is avoided that dynamic, occurring in the sheet metal vibrations Loads are transferred to the screen frame and the foundation, so that the latter can be carried out more easily and yet more reliably.

According to one of the arrangement variants of the sheet metal pairs in the working organ each support is designed in the form of a jaw with one on top of the other Compartments is provided to place one of the trays of the corresponding pair on each compartment put on, with the jaw hinged at one end on a cantilever arm which is arranged on the frame, while its other end by means of a spring is connected to the frame, wherein the cantilever arm is arranged defartam the frame, that it can be moved in the horizontal plane »by the angle of inclination of the metal sheets change in each of the pairs.

According to another variant of the arrangement of the sheet metal pairs in the working body each support is made in the form of a jaw, on which a vibrator and superimposed Compartments are attached, with each compartment a sheet of a corresponding pair is attached and each jaw has a spindle and dampers to the frame is connected, which contains an opening into which the spindle is inserted which when moving the jaw moves and in this way the gap width between the sheets in each pair changes.

The invention is characterized in that the compartments on the jaws are arranged one above the other in such a way that the distance between them gradually decreases, from top to bottom. Such an arrangement of the compartments makes it possible to reduce the dimensions of the vibrating sieve in the vertical direction, it is useful to reduce the weight of the sieve work organ, its dimensions and the costs of the same that the one-piece and hole-free sheets narrow in the direction of movement of the goods moving on them and that each sheet of the following pair has a smaller width than each sheet of the underneath the couple.

In this way, the vibration screen according to the invention has a simple one Construction, light weight and relatively small dimensions, is safe to operate and high performing. The construction of the working organ of this Sieves makes it possible to adjust the gap width during the sieving operation with a minimum expenditure of time to change. In addition, the vibration screen according to the invention does not require any special foundations and can largely be used for the following purposes: - for mechanical Classification of ores both above ground and underground use, - for separation a large fraction of the poor in order to increase the quality of the ore, - for elassing in relation to their size <mined stones for building purpose, to remove pebbles when dismantling soap deposits, - to prepare of lime for burning, - for preparing ores for melting, - for separating small ore fractions before ore mining for crushing, - for sorting Vegetables and fruits according to their piece size.

In the following, the invention will be explained by describing an embodiment of the vibrating screen explained with reference to the drawings; it shows Fig. 1 in a schematic representation the overall view of the viewed from the side Vibration sieve according to the invention, FIG. 2 shows the front view of the one shown in FIG Vibrating sieve, Fig. 3 shows the shape of the gap and the one-piece and perforated metal sheets of the working element according to the invention, FIG. 4 shows another variant the shape of the gap and the sheets, Fig. 5 is another variant of the shape of the Gap and the sheets, Fig. 6 is another variant of the shape of the gap and the Sheets, Fig. 7 one of the arrangement variants of the one-piece and hole-free sheets in Siebararbeitsorgan and Fig. 8 a different arrangement variant of the one-piece and perforated sheets in the working organ.

The vibrating screen has a frame 1 (Fig. 1) on which a Feeding device 2 for the goods to be classified, a device 3 for conveying of the classified material and a working organ 4 are mounted, the latter on Supports 5 of the frame 1 and placed in relation to the conveyor 3 to is inclined at an angle / = 5 - 250.

The feeding device 2 for the material to be classified consists of a bunker with an unloading opening under which the working unit 4 is located, which is used to divide the material to be classified into fractions and to move it the same is intended for the conveyor 3.

The working element 4 consists of two, one-piece and hole-free sheets 6, which are made of metal, plastic or other materials, a smooth Have surface and the length of which is significantly greater than its width. The sheets 6 are arranged at an angle β (FIG. 2) to one another. This angle is in Range from 90 to 1800 depending on the physico-mechanical properties of the chosen property to be classified. The sheets are at such a distance from each other that that between the edges 7 of these sheets 6 a gap 8 for passage through himeiner Fraction of the goods to be classified exists. Here, the sheets 6 are relative to each other so placed on the support 5 that their lower edges 7 in a Height and that the width D (Fig. 3) of the gap 8 between the sheets 6 on remains unchanged over its entire length.

To increase the cross-sectional area of the passage 8, the edges are cut off in a wave-like manner. 7a, FIG. 4) of the sheets 62. In addition, in order to divide the material into several fractions, the sheets 6 can be arranged relative to one another in such a way that the width of the gap 8 (FIG. 5) increases in the direction of the movement of the material on the sheets Direction of movement is indicated by arrow A in the figure. In this case, the width of the gap 8 grows from D1 to D2 uniformly along the entire length of the gap, or it grows in steps, as can be seen from FIG. 6. The step-widening gap 8 is obtained by cutting off the edges 7b of the metal sheets 6 in a step-like manner.

The sheets 6 (Fig. 2) lie loosely on the supports 5 and are prevented from moving on them by cooperating stops 9 and 10. Here are the stops 9 on the underside of each sheet 6, while the stops 10 are attached to the support 5.

On the underside of each sheet 6, a vibrator 11 is attached to to give this sheet an oscillating movement, through which the to be classified Well divided into fractions and these on the sheet metal surface to gap 8 of the conveyor 3 can be moved.

Any desired vibrator for generating an oscillating movement is used as the vibrator 11 suitable, known vibrator, for example an electromechanical, electromagnetic, pneumatic or hydraulic vibrator used.

It is about the dynamic loads which occur when the vibration of the metal sheets 6 arise, to be reduced, between the support 5 and the metal sheets 6 Inserted damper 12, which consist of rubber inserts. The dampers 12 are between the stops 9 and 10 arranged. This is why the stops interact 9 and 10 over the damper 12. This prevents the sheets from moving and damper along the stock 5 move as well as that the oscillating movement is transferred to the support 5 and the frame 1.

It is about the speed of advance of the material along the sheet metal 6 in the direction of the gap 8, the metal sheets 6 are arranged on the supports Sderprt, that they pivoted in the vertical plane to change the angle ß between them can be. For this purpose there is one of the supports 5 or both Support 5 consists of two parts 13 and 14 which are connected to one another by a joint 15 are.

Here, the sheets 6 are arranged on the parts 13, which through the damper 12 and the stops 9 and 10 on the displacement on these parts are prevented while the parts 14 are on the frame 1 on.

Each of the parts 13 has a sector 16 with openings 17 which are arranged one below the other, while each of the parts 14 has a support 18 with in whose opening has inserted bolt 19, which is simultaneously in one of the openings 17 of the sector 16 is seated. When changing the angle ß between the sheets 6 must Bolts 1g can be pulled out of the openings of the sector and the support 18. Thereafter the part 13 of the support 5 must be pivoted about the joint 15 relative to the part 14 and be held in the new position by pushing the bolt 19 into the opening of the Support 18, which coincides with another opening 17 of the sector 16, is used will.

The sheets 6 are arranged on the stock 4 that the Distance between the edges 7 of the sheets 6 can be adjusted, i.e. that the Width of the gap can be changed for this purpose the part 14 of the support understand with a spindle 20, which is guided through a threaded hole that is in a projection 21 of the frame 1 is carried out. By turning the spindle 20 the part 14 moved in the frame, in this way the distance between the lower edges 7> i.e. the width of the gap 8 between the sheets 6, changed will.

The working organ of the vibrating sieve shown in FIG. 2 contains a pair 22 of the one-piece and hole-free sheets 6.

In order to reduce the dimensions of the vibration sieve in the longitudinal direction, his working element 4 (Flgc 7 and 8) except for the pair 22 of the one-piece and perforated metal sheets 6 still under and parallel to these additional pairs 23 of one-piece and hole-free metal sheets 6a, which are analogous to the metal sheets 6. In each of the pairs 23, the metal sheets 6a are arranged at an angle to one another and at a distance from one another, so that gaps 25 arise between their lower edges 24.

Here, each sheet 6a has the following, i.

lower lying pair 23, a width D3 which is less than the width D4 of the sheet 6a or of the sheet 6 of the previous one, i.e. the one above it Pair 23 and 22 respectively.

The sheets 6a of the pairs 23 are arranged so that the lower ones Edges 24 Each subsequent pair closer to each other than the sheet metal edges of the previous one Pairs lie so that the width D5 of the gap 25 of each subsequent pair is smaller than the width D6 of the gap 25 of the preceding pair 23 and 22, respectively. Here through the column 25 of the pairs 23 and the gap 8 of the pair 22 a continuous, Formed from top to bottom tapering passage 26, in which the good moved downwards, with fractions corresponding to their gap size on the pairs 23 to be deposited.

To attach the metal sheets 6 and 6a of the pair 22 and the pairs 23, the supports 5 are designed in the form of jaws, each jaw or one of them is as shown in FIG. 7 and 8 can be seen, with its one end hinged to the cantilever arm 27 inserted into the frame 1, while its other end is connected to the frame 1 by means of a spring 28 and a spindle 29. The spindle 29 is guided through the spring 28 and an opening provided in the frame n. A nut 30 is screwed onto the spindle 29. By moving the nut 30 along the spindle 29, the jaw is rotated in a hinge 31, whereby the angle β between the sheets arranged in pairs and the distance between the edges 24 of the sheets 6a is changed, ie the width of the gaps 25 and correspond , «Changed the width of the passage 26 which is continuous from top to bottom.

The cantilever arm 27 is on the frame 1 attached that it can be moved in the horizontal plane, the angle β between the plates of the pairs 23 and the gap width are also changed. For this purpose, the frame 1 is provided with a hollow pin 32 in which the cantilever arm 27 is located. In the hollow pin 32 and in the cantilever arm 27, bores 33 are provided into which a bolt 34 is inserted in order to hold the cantilever arm 27 in this hollow pin.

To change the angle ß and the width of the column 25, the cantilever arm 27 moved in the hollow pin 32. The bolt 34 is inserted into the hollow pin bore 33, which coincides with another hole in the cantilever arm 27.

On each jaw compartments 35 are attached, on which the sheets 6 and 6a of the pair 22 or the pairs 23 are.

The compartments 35 are on the jaws one above the other in sequence, attached from top to bottom, decreasing distance. Here the sheets have 6 and 6a, as can be seen from Fig. 3 "6, a shape that extends in the direction of movement of the property on the metal sheets is tapered.

The sheets 6 and 6a can be placed on the compartments 35 according to two variants to be ordered.

According to one variant, the sheets 6 (Fig. 7) and 6a are loosely placed on the compartments 35 and the shifting of the same ben on the subjects by attached to the subjects 35 stops 36 and by stops 37, which are located on the underside of the sheets 6 and 6a, prevented. The stops 36 and 37 are designed analogously to the stops 9 and 10 and there are dampers 12 between them. A vibrator 11 is attached to each sheet 6a as well as to the sheets 6.

According to another variant, the sheets 6 and 6a (Fig. 8) attached directly to the compartments 35. This is to create a swinging motion on the To transfer sheets 6 and 6a, one vibrator on each jaw, i.e. on the support 5 11 attached To reduce the dynamic loads that occur when the vibrators are working 11, each jaw rests with its upper and lower end on dampers 38 executed on, Borm of foot pieces) 1 with the one on the frame 1 and the other is located on the support arm 27.

To change the width of the gap 25, one of the jaws is provided with a Spindle 39 is provided, which is guided through an opening provided in the frame. the The jaw is moved by turning a nut 40 seated on the spindle 39.

The obtained fractions of classified goods are carried by the conveyor 3 (Fig. 1) removed, which consists of a conveyor 41 and an inclined chute 42 exists.

The conveyor 41 is under the gap 8 of the working organ 4 or under the through-passage 26 extending from top to bottom (in FIGS. 7 and 8) the conveyor not shown) while the chute 42 is near the face 43 of the metal sheets 6 is arranged.

In the variants in which the working element 4 apart from sheet metal 6 still Contains pairs 23 of metal sheets 6a, the number of inclined chutes 42 is equal to the number of pairs 22 and 23, the slides being near these pairs as is shown in Fig. 1, are arranged.

The vibrating sieve described here works as follows. That The goods to be classified are transferred from the device 2 onto the plates 6 of the sieve work organ 4. After the vibrators 11 have been switched on, the metal sheets 6 perform an oscillating movement by which the material to be classified is caused to be shifted from the upper edges 44 (Fig. 2) of the sheets 6 to the lower edges 7 to begin. Simultaneously the material on these sheets and along these sheets in the direction of inclination moved to the conveyor 3. Under the action of the swaying back and forth Sheets 6 shifts the good with different grain or piece size in Direction of the gap 8 and fractions of the material which contain pieces, their dimensions are smaller than the width of the gap through 8, the gap 8 will fall and get on the conveyor 41.

Fractions of the goods to be classified which contain pieces, their Dimensions larger than the width of the gap 8 are shifted on the sheets 6 along the same and fall on the inclined slide 42 (Fig. 1) of the device 3 for conveying the classified goods.

When a certain fraction is eliminated from the goods to be classified the width of the gap 8 must be changed.

This is done in the manner described above by rotating the spindle 20th

It must, if the physical-mechanical properties (magnification or reduction of admixtures of sticky material, moisture content, bulk density etc.) of the goods to be classified in order to change the process sequence when dividing the goods To improve in fractions, the angle β between the sheets 6 (Fig. 2) changed will. This is done in the manner described above by pivoting the part 13 in relation to part 14 and holding the former in the new position with the aid of the bolt 19.

The operation of the vibrating screen shown in Figs. 7, 8 is basically analogous to the mode of operation of the sieve shown in FIGS. 1, 2. The difference is only that the falling through the gap 8 fractions of the material on metal sheets 6a of the additional pairs 23 arrive on which the goods that have fallen on them in finer fractions corresponding to the width of column 25 is divided. Here are the fractions of the material, which are on the sheets 6a and along the same move, with the help of the slides 42, which are set up in the vicinity of each pair 23 are removed.

In this way, the goods to be classified gradually pass through decreasing piece or grain size from above downward continuous passage 26. The number of fractions of the material to be classified corresponds to the total number of sheet metal pairs of the sieve plus one.

If the grain classes of the material to be classified have to be changed, a setting regulation is carried out to adjust the width of the column 8 and 25 either by simultaneous Moving the cantilever arm 27 and the nut 30 or changing only one of the parts mentioned by moving.

Claims (13)

P A 2 E N T AN S P ß U C E E 1. Vibration sieve with a device for feeding the material to be classified into the working organ, which is located on supports of the frame provided with dampers and receives an oscillating movement from a vibrator to subdivide the material to be classified into fractions and these one to a device Conveying the fractions of classified goods, the working organ being inclined in the direction of the latter device, dadurchge ke nn - characterized in that the working organ (4) consists of at least one pair (22) einteilizer and hole-free sheets (6). wherein the plates (6) of this pair on supports (5) are at an angle to each other, since / 3 between their lower edges (7), which are at one level, a gap (8) for the passage of a fraction of classified material - stands, 2. Vibration sieve according to claim 1, characterized in that the metal sheets (6) relative to one another on the supports (5) are arranged that the width of the gap (8) increases in the direction of the inclination of the working organ (4). 3. Vibration sieve according to claim 2, d a d u r c h g e -k e n n z e i c h n e t that the sheets (6) are arranged on the supports (5) in such a way that they are in the vertical plane are pivotable to the angle of inclination to change between the sheets. 4. Vibration sieve according to claim 3, d a d u r c h g e -k e n n z e i c h n e t that for pivoting the plates (6) at least one of the supports (5) consists of two parts (13 and 14) connected to one another in an articulated manner, with an one of them (part 13) a plate (6) arranged and a sector (16) with a Series of openings (17) is provided, while the other part (part 14) on the Frame (1) uitieg and has a bolt (19) that goes into one of the openings (17) of the sector (16) is slidable 5. vibrating sieve according to claim 4, d a d u r c h It is noted that the part of the Auflagers has a spindle (20), while running a threaded hole in the frame (1) is, in which the spindle (20) is displaceable to in this way the part of the To move the support on the frame in order to increase the width of the gap (8) to change between the sheets (6). 6. Vibration sieve according to claim 1, dadurchge -kennze ichnet> that under the pair (22) of the one-piece and hole-free sheets (6) additional pairs (23) with (23) sheets (6a) are arranged, the sheets ( 6a) are mounted at an angle to each other and at such a distance that between their lower edges (24) there is a gap (25), the width of which in each case Lying pair is less than the gap width of the previous pair, while the gap (25) of all pairs (22 and 23) form a tapering passage (26) which is continuous from top to bottom for the advancement of the material along this passage, whereby at the same time fractions corresponding to these are separated from the goods on the sheet metal pairs. 7. vibrating sieve according to claim 1 or 6, d a d u r c h g e k e n n z e i c h n e t that on the underside of the metal sheets (6 and 6a) stops (9 and respectively 37) are provided, which interact with those carried out on the supports (5) Stops (10 or 36) are available to move the sheets on them To prevent sedimentation. 8. Vibration sieve according to claim 7, dadurchgo -kennze ichnet that the vibrators (11) are attached to the metal sheets (6 or 6a), while the Damper (12) are arranged between the stops (9 and 10 of the sheets (6,60) and the support (5). 9. Vibration sieve according to claims 6 to 8, characterized in that, to accommodate the pairs of sheets (22 and 23), each support (5) is designed in the form of a jaw which is provided with superimposed compartments (35), on each compartment one of the trays of the corresponding the pair aurlegertrst wherein the jaw is hinged with its one end on a cantilever arm (27) which is arranged on the frame (1), while its other end is connected to the frame (1) by means of a bed (28), the Cantilever (27) is arranged on the frame (1) that it is displaceable in the horizontal plane in order to change the angle of inclination of the sheets in each of the pairs. 10. Vibration sieve according to claim 6, d a d u r c h g e k e n n z e i c h n e t that to accommodate the sheet metal. Pairs (22 and 23) each support (5) executed in the form of a jaw is to which a vibrator (11) and superimposed compartments (35) are attached, a sheet (6 or 6a) of a corresponding pair being attached to each compartment and each jaw has a spindle (39) and via dampers (38) to the frame (1) is connected, which contains an opening into which the spindle (39) is inserted which moves the cheek when it moves, and in this way the width of the gap (25) between the sheets in each pair changes. 11. Vibration sieve according to one of claims 9 od. 10, characterized in that the compartments (35) on the jaws one above the other are arranged so that the distance between them gradually diminishes, from top to bottom. 12. vibrating screen according to any one of claims 1 to 11, d u r c h e k e n n n z e i c h n e t that the sheets (6 or 6a) in the direction of movement of the goods shifting on them become narrower. 13. Vibration sieve according to claim 6, dadurchge -kennz eichnet that each sheet (6a) of the following pair has a width smaller than the width of the sheet (6 or 6a) of the Lying couple owns.