WO2022127994A1

WO2022127994A1 - Worm-shaft separator bucket and worm-shaft screen device

Info

Publication number: WO2022127994A1
Application number: PCT/DE2021/101005
Authority: WO
Inventors: Clemens Rickert
Original assignee: Schnelting, Mathias
Priority date: 2020-12-15
Filing date: 2021-12-14
Publication date: 2022-06-23
Also published as: EP4263957A1; EP4263958A1; WO2022127993A1

Abstract

A separator bucket has two lateral cheeks, a bucket floor arranged between the lateral cheeks, a bucket back arranged between the lateral cheeks and contiguous to the bucket floor, and a drive device, the bucket floor and/or the bucket back having a screen surface with a multitude of mutually interspaced worm shafts that can be rotated by means of the drive device.

Description

Worm shaft:

and

The present invention relates to a separator shovel for attachment to working implements, such as excavators, wheel loaders or similar implements. A separator blade can be used to separate coarse soil from fine soil material. While the coarse soil material is retained in the bucket, the fine soil material can trickle out of the bucket through a plurality of openings.

Separator blades are known which have a loading opening at the front and a blade back which is essentially parallel to the loading opening at the rear and which is designed as a screen surface and comprises two or three rotationally symmetrically rotatable screen shafts/screen drums.

The disadvantage of the known separator shovels is that material often gets jammed between the screen shafts or between the screen shafts and side walls and that the shovels only have a low screening capacity.

The object of the invention is to provide a separator blade that overcomes the disadvantages known from the prior art. Thus, in particular, the task can be seen as providing a separator blade that prevents the material from jamming between the screen shafts or between the screen shafts and side walls. A further object can be seen in providing a shovel with an increased screening performance.

To solve the problem, a separator blade is provided, comprising two side walls, a blade base arranged between the side walls, a blade rear arranged between the side walls and adjoining the blade base, and a drive device, the blade base and/or the blade rear having a screen surface that has a A plurality of worm shafts that are spaced apart from one another and can be rotated by the drive device.

The material in the shovel is moved by the rotating auger shafts in such a way that the fine material can trickle through the openings between the shafts. Here, the material not only performs an essentially two-dimensional movement, as for example in the blade separators known from the prior art, but is also conveyed or moved along the screw shafts and thus performs a three-dimensional movement. This goes hand in hand with increased sieving and separating performance and a reduction in the risk of material becoming jammed.

A worm shaft is a shaft with a worm spiral running around it. Worm shafts thus comprise a worm helix, which as a rule extends as a wound metal sheet around a cylindrical or tubular worm hub on the outside. Each of the shafts of the screen surface is preferably designed as a worm shaft. In addition to these classic worm shafts, worm shafts can also be understood according to the invention as shafts with a large number of discs which are arranged obliquely to the axis of rotation of the shafts and are spaced apart from one another and surround the shaft circumferentially. The angles between the discs and the shaft hubs on which the discs are arranged are preferably the same over the entire screen surface and are preferably in the range of 20°-70°. With adjacent shafts driven in opposite directions, the material on these shafts with the skewed discs is not transported in one direction, but rather distorts a left-right jogging motion.

The blade base can form a flat and/or an upwardly curved surface. The upwardly curved surface of the blade bottom can have different radii of curvature. The blade base preferably has a flat surface, which preferably bears tangentially on the cutting edge, with the flat surface merging into a surface curved upwards. According to the invention, the blade base is defined as the surface that lies in a plane spanned by the cutting edge and the surface that borders the cutting edge and whose tangents of the circle of curvature associated with the respective point of contact form an angle of less than 90° to the plane spanned by the cutting edge . At a larger angle, the face is defined as the back of the blade.

The bucket bottom may include a screen surface formed by spaced worm shafts. The blade back can comprise a screening surface formed by screw shafts spaced apart from one another. Preferably, both the blade base and the blade back each comprise a screen surface. Preferably, the shovel has a bucket base lying at the bottom and running continuously upwards, with the bucket base merging directly into the back of the bucket. A separator shovel in which the bottom of the shovel includes a sieve surface enables the excavated material to be separated during the shoveling process. The screen surface of the blade base preferably extends into the back of the blade. The shovel thus preferably comprises a large coherent screen surface formed by the screw shafts. Such a separator blade enables screening in almost any blade position.

The cutting edge is preferably designed as a plate which forms the front part of the blade base.

The rotatable screw shafts are therefore preferably not arranged in one plane. The screen surface is preferably formed entirely by the screw shafts.

The screw shafts are arranged at a distance from one another in such a way that there are clearances between the shafts, which represent the screen openings. The screen surface preferably comprises at least 5, particularly preferably at least 10, screw shafts. All screw shafts are preferably of identical design. The worm shafts preferably extend from one side wall to the other side wall, the worm shafts particularly preferably extending through both side walls. The screw shafts are preferably arranged in such a way that they can rotate about their longitudinal axes, which are arranged parallel to one another. The worm shafts are preferably rotatably mounted in bearings on the outside of the side walls.

The drive device is designed in such a way that it can set the worm shafts into a preferably synchronous rotation.

In an advantageous embodiment of the invention, the screen area takes up at least 50%, preferably at least 70%, particularly preferably at least 90% of the area of the blade base. The cutting edge preferably occupies less than 50%, preferably less than 30%, particularly preferably less than 10% of the area of the blade base. With such a screen surface, a large part of the shovel base is available as a screen surface, so that efficient screening is guaranteed.

In an advantageous embodiment of the invention, the screen surface occupies at least 50%, preferably at least 70%, particularly preferably at least 90% of the surface of the back of the blade.

In an advantageous embodiment, the worm shafts are designed as non-intermeshing worm shafts. The coiled metal sheet preferably protrudes radially outward approximately at right angles from the screw hub to such an extent that the metal sheet or the screw helix only almost touches the screw helix of the adjacent screw shafts. Thus, in the case of two adjacent worm shafts, the sum of the lengths that the spirals extend radially outward is less than the distance between the worm hubs of these worm shafts. Such an embodiment further reduces the risk of material becoming jammed between two adjacent screw shafts. In addition, such an embodiment allows an asynchronous rotation of the worm shafts, i.e. a rotation with different

Rotational speeds, so also a rotation with different

directions of rotation.

Each worm shaft preferably runs through an intermediate bearing, which is preferably arranged in a web running parallel to the side walls. Intermediate bearings of this type are particularly advantageous for stabilizing the screw shafts in the case of a wide separator blade, in which the side walls are spaced far apart from one another. It is also provided according to the invention that each worm shaft runs through more than one intermediate bearing.

Bearings of a worm shaft are to be understood as meaning the bearings of a worm shaft through which the worm shaft runs. These bearings can thus be the bearings arranged on the side cheeks as well as intermediate bearings. Neighboring bearings of a worm shaft are therefore not to be understood as meaning the bearings of different worm shafts. Each shaft of the screen surface is preferably designed as a worm shaft over the entire length with a worm helix running around the worm hub.

Each worm shaft preferably has at least one left-hand helix and at least one right-hand helix area. Each worm shaft particularly preferably has exactly one left-hand helix and exactly one right-hand helix region between two adjacent bearings of the respective worm shaft. According to the invention, “adjacent” means the components that are arranged directly adjacent.

Screw shafts of this type, which have one or more left-hand helix and one or more right-hand helix areas, have an increased separating capacity, since the coarse material lying directly on the screw shaft is not transported over the entire length to a side wall before it is pushed away from the shovel bottom, but rather is only transported a short distance directly resting on the worm shaft. In an advantageous embodiment, the left and right-hand coiled areas of each worm shaft are arranged in such a way that material located on the respective worm shaft is conveyed away from the bearings of the respective worm shaft when the worm shaft rotates. With worm shafts of this type, the risk of material becoming jammed between the worm shaft or shafts and the side walls or the central web is further reduced.

Preferably, all of the worm shafts are aligned such that the worm flights of the shafts face the worm flights of the adjacent shafts and almost contact each other. The screw shafts are thus preferably aligned in such a way that the helixes have the smallest possible distance--in the direction perpendicular to the longitudinal axis of the shafts--to the helixes of the adjacent screw shafts. This means that the worm shafts are aligned in such a way that the imaginary radial extensions of the flights of each worm shaft are exactly aligned with the flights of the adjacent worm shafts. In such an embodiment, each worm shaft is thus arranged in a different rotational position than the adjacent worm shafts. Preferably, every other worm shaft is in the same rotational position. Preferably half of the worm shafts are arranged in a first rotational position and the other half of the worm shafts are arranged in the second rotational position. Preferably, in the first rotational position, the shafts are rotated by exactly 180° about the longitudinal axis compared to the second rotational position.

Screw pitch is to be understood as meaning the distance parallel to the longitudinal axis of the screw shaft between two adjacent partial coil elements of a coil. All screw shafts preferably have a uniform and constant screw pitch. In an advantageous embodiment, the pitch of the worm spirals of the worm shafts is equal to or greater than the distance between two adjacent worm shaft hubs, the gap dimension. In such an embodiment, the smallest screen opening in the transverse direction, ie perpendicular to the longitudinal axis of the waves, by the distance between the Worm shaft hubs fixed to each other. The minimum openings between two spirals of two worm shafts facing each other are not taken into account here. The gap dimension is preferably uniformly large over the entire screen surface, regardless of the rotational position. The size of the screen openings in the longitudinal direction are determined by the screw shaft pitches.

Preferably, the worm flights or the edges of the worm flights, at least the worm flights that are arranged next to a fixed element, such as a side wall or web, are rounded off or provided with a chamfer. The screw flights are preferably designed in such a way that they have a conical cross-sectional profile. This prevents material from becoming jammed between a worm shaft and a stationary element, as the material is pushed up along the helix by the hub. This can be of particular importance in reversing operation, in which the material is transported in the direction of the side wall.

The worm shafts preferably include one or more areas in which the worm hubs are designed with an enlarged diameter, that is to say thickened, and/or one or more areas in which a casing surrounds the worm shaft. The distance from a thickened screw shaft hub or casing to a thickened screw shaft hub or casing of an adjacent screw shaft preferably corresponds to the gap size, ie the desired screening. In these areas with a thickened worm shaft hub and/or casing, the worm shafts preferably do not include worm flights or worm flights with a reduced screw flight height. These portions of the auger shafts are preferably located where the left and right hand helixes meet and/or between the exit auger flights and a bearing. This has the advantage that the risk of jamming of material between screw flights of two adjacent screw shafts or between the screw shafts and one Side wall or a web with intermediate bearings is significantly reduced. In cases where all worm shafts are aligned identically and are therefore in the same rotational position, if there is no thickening or casing, there may be a larger gap than the desired gap in these areas. The casing can be ring-shaped and have a conical cross-sectional profile. The thickening of the worm shaft hub can be bead-shaped or can extend circumferentially outwards with a conical cross-sectional profile.

In an advantageous embodiment of the invention, the worm shafts are driven alternately. The screw shafts are preferably driven alternately on the left and right. Every second shaft is therefore driven from the left-hand side frame and the shafts in between are driven from the right-hand side frame.

Preferably, the drive device includes at least one gear. Preferably, the drive device comprises a gearbox on each outer side of the side walls. Each worm shaft is preferably coupled to a gearbox. A shaft is preferably coupled to the transmission by means of a power transmission wheel, preferably in the form of a gear wheel. The power transmission wheel can be part of the worm shaft or, in a multi-part embodiment, the shaft can be non-rotatably connected to the power transmission wheel. Preferably, the power transmission wheel is located at one of the head ends of the shaft.

The other head end of the worm shaft can also comprise a gear wheel which is preferably not non-rotatably connected to the shaft but is used, for example, only to guide the chain or toothed belt of a gear arranged on the side of this gear wheel, but not to drive the worm shaft.

The power transmission wheels are preferably part of the transmission/transmissions of the drive device. Toothed belt, chain and/or spur gears can be used as gears. These gears can be disguised be, preferably each with an outer, ie second, side wall on each side of the separator blade. The gearboxes are preferably provided with a complete outer covering. Such a cover prevents contamination of the gears during the shoveling process.

Preferably a pin engages each power transmission wheel from the side not connected to the worm shaft. The power transmission gears can thus form bearings together with the engaging bolts. The ends of the worm shafts not connected to the power transmission gears may form bearings together with bolts engaging those ends of the worm shafts. The power transmission wheels of two adjacent worm shafts are preferably arranged on opposite side cheeks. A dirt-resistant and narrow construction is achieved by means of such internal bearings. Alternatively, the bolts can be connected to the screen shaft, with the bolts preferably being mounted on the outside of the side walls. The power transmission wheels can be connected to the bolts on the outside of the side walls. The bearing is thus arranged behind the power transmission wheel when viewed from the screen shaft.

Bearings of this type have the advantage that the dirt has to overcome a large number of dirt barriers, such as a labyrinth seal, a shaft seal, a gear box and a drive chain, before it can penetrate into the bearing and cause damage. On the one hand, it is very unlikely that dirt can reach the bearing point at all, on the other hand, the escaping oil would push the dirt out and the leakage would signal a defect in the machine to the user. In contrast, in the designs known from the prior art, the bearing is located between the screen shaft and the drive. Dirt penetrating through the shaft sealing ring would directly destroy the bearing and cause major damage to the drive.

The gears arranged on the two side panels are preferably chain or toothed belt gears. Each transmission preferably comprises only one chain or a timing belt. The chain or toothed belt is preferably driven by a hydraulic motor or connecting shaft and is connected to the power transmission wheels of the screen shafts such that movement of the chain or toothed belt rotates the screen shafts.

The chain or toothed belt drives preferably each have a tensioning device in order to keep the chain or the toothed belt tensioned. The tensioning device preferably comprises a hydraulic cylinder, particularly preferably in the form of a synchronous cylinder. A piston rod of the cylinder can be connected to a rotatably mounted gear which can engage in the chain or the toothed belt of the respective transmission and tension it. The chain or toothed belt is preferably tensioned by a spring. The reversing operation can be blocked via the synchronized cylinder. The synchronous cylinder preferably comprises two chambers which are connected to one another via a non-return valve. During clamping, the oil can flow from one chamber into the other. When the direction of rotation is reversed, the built-in non-return valve is activated and the entire piston surface is available. In this way, the very high forces that arise in reversing operation can be absorbed. In this way, the same force can be constantly applied and thus the same chain tension can be maintained. This backlash-free chain tension is important for the function and durability of the drive.

The separator blade preferably includes a connecting shaft for coupling and synchronizing the gears arranged on both side walls. This connecting shaft thus connects these two transmissions to one another. One of the worm shafts is preferably designed as a connecting shaft. A connecting shaft may have a power transmission wheel at both ends of the shaft and transmit the power from the gearbox on one side to the gearbox on the other side. In this way, an exact synchronism of the gears and thus a synchronous rotation of the screen shafts can be achieved. The connecting shaft can be regarded as part of the drive device. In an advantageous embodiment, the drive device, preferably the connecting shaft of the drive device, comprises a coupling for adjusting the rotational position of each second worm shaft relative to the worm shafts lying in between. This clutch is preferably a cam clutch. With such an adjustment option, the worm shafts can be aligned in such a way that the imaginary radial extensions of the helixes of each worm shaft are arranged between the helixes of the adjacent worm shafts. The helix of each worm shaft is thus preferably not directed in the direction of the helixes of the adjacent worm shafts, but towards the hubs of the adjacent worm shafts. The screen openings can be changed by adjusting the rotational positions of the screw shafts in relation to one another. In an advantageous embodiment, all worm shafts are aligned identically and are therefore in the same rotational position.

In an advantageous embodiment of the invention, the coupling of the worm shafts to the drive device can be changed from a first type of coupling to a second type of coupling. In the first type of coupling, the drive device is designed to rotate the worm shafts in such a way that all worm shafts have the same direction of rotation. In the second type of coupling, the drive device is designed to rotate the worm shafts in such a way that adjacent worm shafts rotate in opposite directions. Changing from the first type of coupling to the second type of coupling can be achieved, for example, by changing the running of the chain on the gearing of a side wall. It is thus possible to switch from a worm shaft rotation with the same direction of rotation to a worm shaft rotation with different directions of rotation.

The present invention also relates to a screening device with a drive device and a screening surface with the features or properties of the screening surface or the drive device defined above in connection with the separator blade. The description of the separator blade according to the invention and the screening device according to the invention are therefore to be understood as complementary to one another, so that information regarding the screening surface and the drive device, which are explained in connection with the separator blade, are also individually or combined as information on the screening surface and the drive device of the screening device are to be understood.

In an advantageous embodiment, the screening device comprises a screening surface and a drive device, the screening surface having a multiplicity of screw shafts which are spaced apart from one another and can be rotated by the drive device.

In an advantageous embodiment, the screening surface of the screening device comprises a large number of screw shafts that are spaced apart from one another and can be rotated by the drive device, which screw shafts can be designed as non-intermeshing screw shafts and/or can have at least one left-handed and at least one right-handed area, preferably with each screw shaft exactly has a left-hand helix and exactly one right-hand helix area between two adjacent bearings of the respective worm shaft, it being possible for the left-hand and right-hand helix areas of each worm shaft to be arranged in such a way that material located on the respective worm shaft is conveyed away from the bearings of the respective worm shaft when the worm shaft rotates , and/or arranged such that each worm shaft is arranged in a different rotational position than the adjacent worm shafts, and/or the mutually may be driven, wherein there may be a connecting shaft for coupling and synchronizing the mutually driven screw shafts, the drive being by means of the drive device, which may have at least one gear, preferably a gear on each outside of the screen surface, each Worm shaft can be coupled to a gear, preferably wherein the coupling takes place by means of a power transmission wheel, wherein the gear is preferably a chain or a toothed belt gear and comprises a tensioning device in the form of a hydraulic cylinder, the hydraulic cylinder preferably being a synchronous cylinder with two piston rods, wherein the piston rods may differ in diameter, and/or may include one or more areas where the worm hubs are designed to be enlarged in diameter and/or may include one or more areas where a shroud surrounds the worm shaft hub, and/or a pitch of the worm flights of the worm shafts, which is equal to or greater than the distance between two adjacent worm shaft hubs, and/or

can comprise screw flights which are at least partially rounded or provided with a chamfer or are designed in such a way that they have a conical cross-sectional profile,

In an advantageous embodiment, the screen shafts of the screening device are arranged in one plane.

The invention is explained again below by way of example with reference to the figures.

1 shows an exemplary embodiment of a separator blade.

FIG. 2 shows a partial illustration of an exemplary embodiment of a screen surface of a separator blade.

3 shows partial illustrations of an exemplary embodiment of a separator blade. 4 shows an exemplary embodiment of a bearing of a separator blade.

FIG. 5 shows an exemplary embodiment of a chain drive of a separator blade.

FIG. 6 shows an exemplary embodiment of a worm shaft for a separator blade in a side view (FIG. 6A) and as a cross-sectional drawing (FIG. 6B).

1 shows an exemplary embodiment of a separator blade 1 with two side walls 2, 3, between which a blade base 4 is arranged, which has a cutting edge 6 at the front. The blade base 4 curves upwards and merges directly into the blade back 5 . Downstream of the cutting edge 6, the blade bottom 4 includes a screen surface 7 that extends into the blade back 5 and includes a large number of worm shafts, such as worm shaft 8, that are spaced apart from one another and can be rotated by a drive device. The blade base 4, with the exception of the cutting edge 6, and the blade back 5 are designed entirely as a screen surface 7.

FIG. 2 shows a partial illustration of an exemplary embodiment of a screen surface of a separator blade. The excerpts of the worm shafts 8, 80 shown each have a worm hub 85, 87 with a spirally running worm helix 86, 88. the

Worm turning pitch, ie the distance parallel to the longitudinal axis of the worm shaft between two adjacent partial coil elements of a coil, is marked with a. The distance between two adjacent worm shaft hubs, i.e. the gap size, is marked with b. In the embodiment shown here, a>b.

3A shows a partial representation of an exemplary embodiment of a separator blade comprising a plurality of screw shafts (eg 8, 80) each running between the side walls, the screw shafts each run through an intermediate bearing 10, which is arranged in a web 9 arranged parallel to the side walls. Between the adjacent bearings, i.e. between the bearing of the left side cheek and the bearing of the center bar and between the bearing of the center bar and the bearing of the right side cheek, each worm shaft has a left-hand helix and a right-hand helix area, with the areas being arranged in such a way that the material is conveyed away from the bearings along the worm shafts.

FIG. 3B shows an enlarged detail from FIG. 3A. Each worm shaft is rotated 180° around the axis of rotation relative to the two adjacent worm shafts. This position of the worm shafts relative to one another does not change during the synchronous rotation of the worm shafts.

Figure 3C shows the separator blade of Figure 3B. Half of the worm shafts are driven by a gear on the left and the other half by a gear on the right side wall, with the worm shafts that can be rotated by the left and the right gear alternating. One half of the worm shafts (including worm shaft 8), for example those which are driven via the gearbox arranged on the right side wall, have been rotated by 180° around the axis of rotation (e.g. by adjusting the coupling of the connecting shaft) compared to the separator blade from Fig. 3C ). FIG. 3D shows an enlarged detail from FIG. 3C. In the embodiment shown, all the worm shafts are thus aligned identically and are therefore in the same rotational position.

4 shows an exemplary embodiment of a bearing of a separator blade. The worm shaft 81 is rotatably mounted, the bearing being formed by a bolt 12 which engages in the power transmission wheel 11 connected to the screen shaft 81 . The power transmission wheel 11 is part of a chain drive which is arranged on this side wall (not shown).

Fig. 5 shows an exemplary embodiment of a chain transmission

separator blade. The chain gear is on the outside of the side panel 3 arranged and includes the chain 90 and a plurality of power transmission wheels 11, 15, 16, 17, 18, 19, 20, which are non-rotatably connected to the head ends of the worm shafts and the connecting shaft 22. On this side wall, every second worm shaft is non-rotatably connected to a power transmission wheel. The worm shafts, which are not non-rotatably connected to a power transmission wheel on this side wall, are driven via another gear on the other side wall. These worm shafts can be non-rotatably connected to the side wall 3 each with a gear 21, which serves to guide the chain. The chain transmission is driven via the connecting shaft 22. A tensioning device 23 , which includes a synchronous cylinder 24 , ensures the chain tension.

FIG. 6A shows an exemplary embodiment of a worm shaft 91 having four worm flights 93, with an area for forming a bearing or shroud 92 being disposed between each worm flight. Such a casing is arranged between the areas in which a left-hand screw helix meets a right-hand screw helix.

FIG. 6B shows the worm shaft of FIG. 6A as a cross-sectional drawing. The shroud 92 is a type of ring with a conical cross-section surrounding the screw hub. The worm flights 93 also have a conical cross-sectional profile.

Reference List

1 ) Separator blade

2) sidewall

3) sidewall

4) Bucket bottom

5) blade back

6) cutting edge

7) screen surface

8) Worm shaft ) Web 0) Intermediate bearing 1 ) Power transmission wheel 2) Bolt 5) Power transmission wheel 6) Power transmission wheel 7) Power transmission wheel 8) Power transmission wheel 9) Power transmission wheel 0) Power transmission wheel 1 ) Gear 2) Connecting shaft 3) Tensioning device 4) Synchronization cylinder 0) Worm shaft 5) Worm hub 6) Worm turn i7) Worm hub 8) Worm turn i0) Chain 1 ) Worm shaft 2 ) Sheathing 3) Worm spiral egg

Claims

patent claims

1. Separator blade comprising two side walls, a blade base arranged between the side walls, a blade rear arranged between the side walls and adjoining the blade base, and a drive device, wherein the blade base and/or the blade rear has a screen surface which has a plurality of mutually spaced and through the drive device comprises worm shafts which can be set in rotation.

2. Separator blade according to claim 1, wherein the worm shafts are designed as non-meshing worm shafts.

3. Separator blade according to claim 1 or 2, wherein each worm shaft has at least one left-hand helix and at least one right-hand helix area, preferably wherein each worm shaft has exactly one left-hand helix and exactly one right-hand helix area between two adjacent bearings of the respective worm shaft.

4. Separator blade according to one of claims 1 to 3, wherein the left-hand and right-hand helix areas of each worm shaft are arranged such that material located on the respective worm shaft is conveyed away from the bearings of the respective worm shaft upon rotation of the worm shaft.

5. Separator blade according to one of claims 1 to 4, wherein the screw shafts comprise one or more areas in which the screw hubs are designed to be enlarged in diameter and/or comprise one or more areas in which a casing surrounds a screw shaft hub, preferably these areas located where the left and right hand helixes meet and/or between the outgoing helixes and a bearing. Separator blade according to one of Claims 1 to 5, in which the pitch of the worm flights of the worm shafts is equal to or greater than the distance between two adjacent worm shaft bosses. Separator blade according to one of claims 1 to 6, wherein at least part of the screw flights are rounded or provided with a chamfer or are formed in such a way that they have a conical cross-sectional profile. A separator blade according to any one of claims 1 to 7, wherein the worm shafts are reciprocally driven. A separator blade according to claim 8, wherein the drive means comprises a connecting shaft for coupling and synchronizing the mutually driven worm shafts. Separator blade according to any one of claims 1 to 9, wherein the drive device, preferably the connecting shaft of the drive device, comprises a clutch for adjusting the rotational position of each second worm shaft to the intermediate worm shafts. Separator blade according to one of claims 1 to 10, wherein the coupling of the worm shafts to the drive device from a first type of coupling, in which the drive device is designed to rotate the worm shafts in such a way that all worm shafts have the same direction of rotation, to a second type of coupling, in which the drive device is designed to rotate the worm shafts in such a way that adjacent worm shafts have an opposite direction of rotation. Separator blade according to one of claims 1 to 11, wherein the drive device at least one gear, preferably a gear each outer side of the side walls, wherein each worm shaft is coupled to a gear, preferably wherein the coupling takes place by means of a power transmission wheel, preferably wherein the bearing of the worm shaft is arranged behind the power transmission wheel, viewed from the screen shaft Separator blade according to claim 12, wherein the at least one Transmission is a chain or a toothed belt transmission and includes a tensioning device in the form of a hydraulic cylinder, the hydraulic cylinder preferably being a synchronous cylinder with two chambers which are connected to one another via a check valve. Separator blade according to one of claims 1 to 13, wherein the screen surface adjoins a cutting edge of the blade base and forms an upwardly curved surface, preferably with different radii of curvature, which preferably extends into the back of the blade. A screening device comprising a screening surface and a drive device, the screening surface comprising a plurality of worm shafts which are spaced apart from one another and can be rotated by the drive device, the worm shafts being driven alternately.