Patent Description:
A first known type of screening bucket comprises a basket-shaped structure that forms a lattice wall and defines a loading opening. Screening is performed by loading the debris material into the basket through the loading opening, and rotating the basket about its own rotation axis, so as to eject the debris material contained through the filtering lattice wall. Thus, only debris material that is smaller than the size of the lattice of the lattice wall is ejected from the basket, while debris material that is larger than the size of the lattice remains inside the basket.

For example, such a solution is known from <CIT>.

However, this first type of screening bucket is not adapted to exert high forces on the debris material to be screened, and therefore is not suitable for performing effective crushing of the debris material.

A second known type of screening bucket, also suitable for crushing debris material, comprises a box-shaped bucket body defining a loading chamber for picking up debris material into the screening bucket, and a discharge opening for discharging the screened debris material.

Further, these screening buckets comprise a screening unit, which generally comprises a plurality of pinions that may be moved in rotation by feed and drive means.

The pinion is a mechanical member comprising a screening shaft rotatable about a rotational axis, and a plurality of screening blades connected to the screening shaft and extending radially with respect to the rotational axis of the screening shaft.

Solutions of this type are known for example from <CIT>, from the same applicant, and also from <CIT>, <CIT>, <CIT>, <CIT>, <CIT>. <CIT> also discloses such an apparatus.

Since the presence of stones and rocks in the debris to be screened may cause very high stresses on the pinions, it is known to form both the screening blades and the screening shaft of steel, and to weld the screening blades to the screening shaft.

This solution, while satisfactory for the purpose of crushing and screening debris, involves significant operating and maintenance costs.

In fact, in case of damage or breakage to one of the screening blades of the pinion, it is necessary to replace the entire pinion with a new one, disassembling its support shaft and pulling out the pinion for its complete replacement.

The object of this invention is to provide a screening bucket such that it may overcome at least some of the drawbacks highlighted in the prior art.

A particular object of this invention is to provide a screening bucket that requires less complex maintenance and operation and reduced costs, while offering high mechanical strength.

These and other objects are achieved by a screening bucket according to claim <NUM>.

The dependent claims relate to preferred and advantageous embodiments of this invention.

In order to better understand the invention and appreciate its advantages, some of its exemplifying and non-limiting embodiments will be described below, referring to the appended figures, wherein:.

With reference to the figures, a screening bucket is generally indicated with reference <NUM>.

The screening bucket <NUM> comprises a box-shaped bucket body <NUM> defining a loading compartment <NUM> and an unloading opening <NUM>.

The screening bucket <NUM> further comprises a screening unit <NUM> configured to screen debris material.

The screening unit <NUM> comprises at least one pinion <NUM>, and drive and transmission means <NUM> configured to generate and transmit a rotary motion to the at least one pinion <NUM>.

The screening unit <NUM> comprises at least one screening shaft <NUM> rotatable about a rotation axis <NUM>. The at least one pinion <NUM> is mounted on the screening shaft <NUM>.

Further, the at least one pinion <NUM> comprises a plurality of screening blades <NUM> connected to the screening shaft <NUM> and extending along a radial direction R-R orthogonal to the rotation axis <NUM>.

According to an aspect of the invention, the at least one screening blade <NUM> of the plurality of screening blades <NUM> comprises two screening half-blades 8A, 8B connected to the screening shaft <NUM>.

Further, each screening half-blade 8A, 8B is connected to the screening shaft <NUM> approaching along said radial direction R-R.

Further, each screening half-blade 8A, 8B is connected to the screening shaft <NUM> by a positive mechanical connection <NUM>.

Further, the positive mechanical connection <NUM> is reversible, to allow said each half-blade 8A, 8B to be disconnected from said screening shaft <NUM>.

A screening bucket <NUM> configured in this manner requires easier maintenance and handling.

In effect, in case of damage to a screening blade <NUM>, or in case of a change of application, the screening bucket <NUM> so configured allows a localized and direct replacement of the single blade, or half-blade, with a new spare screening blade, or half-blade <NUM>, or of a type more suitable for the new application.

As a further advantage, a screening bucket <NUM> so configured allows for localized replacement of the single blade, or half-blade, without therefore requiring handling and removal of the entire pinion, or additional screening blades arranged on the same pinion, in order to reach the screening single blade or half-blade <NUM> that is to be replaced.

According to an embodiment, the screening half-blade 8A, 8B has a substantially plate-like shape.

The screening half-blade 8A, 8B defines a screening wall <NUM> facing away, or away from, the screening shaft <NUM> and configured to screen and crush debris material, and a connection wall <NUM> facing the screening shaft <NUM>.

According to an embodiment, the screening wall <NUM> forms a scalloping <NUM>.

According to an embodiment, the scalloping <NUM> comprises a plurality of scallops <NUM> with a substantially trapezoidal or arched shape.

According to an embodiment, the pinion <NUM> comprises at least two screening blades <NUM>, wherein the scalloping <NUM> of one of the two screening blades <NUM> is different from the scalloping <NUM> of the other of the two screening blades <NUM>.

According to an embodiment, the scalloping <NUM> of one of the two screening blades <NUM> forms a different number of scallops <NUM> with respect to the number of scallops <NUM> formed by the scalloping <NUM> of the other screening blade <NUM>.

Alternatively, the pattern of the scallops <NUM> of one screening blade <NUM> differs from the pattern of the scallops <NUM> of the other screening blade <NUM> (<FIG>).

According to a further alternative, the pattern of the scallops <NUM> of at least two screening blades <NUM> of the same pinion <NUM> is substantially identical (<FIG>).

According to an embodiment, the screening half-blade 8A, 8B comprises at least one auxiliary screening element <NUM> connected to the screening wall <NUM> (<FIG>). The at least one auxiliary screening element <NUM> is removably connectable or welded to the screening wall <NUM>.

Advantageously, the arrangement of at least one screening auxiliary element <NUM> is carried out in relation to the specific material to be processed by the screening bucket <NUM>, thereby making it more efficient and adaptable.

According to an embodiment, the screening half-blade 8A, 8B defines a plurality of lightening holes <NUM>, internal to the screening half-blade 8A, 8B.

According to an embodiment, the screening half-blades 8A, 8B are made of steel.

According to an embodiment, two screening half-blades 8A, 8B of a same screening blade <NUM> are connected opposite to each other with respect to the screening shaft <NUM>.

According to an embodiment, the positive mechanical connection <NUM> comprises positioning and fastening means <NUM> by which a screening half-blade 8A, 8B is connected to the screening shaft <NUM> at a predefined connection position <NUM>.

According to an embodiment of the invention, the positioning and fastening means <NUM> comprise a pin <NUM> connected to the connection wall <NUM> of the screening half-blade 8A, 8B.

Further, the positioning and fastening means <NUM> comprise a positioning hole <NUM> defined by the screening shaft <NUM> and extending into the screening shaft <NUM> along the direction R-R.

The positioning hole <NUM> is configured to accommodate the pin <NUM>.

According to an embodiment, the screening shaft <NUM> defines a pair of positioning holes <NUM>, one opposite the other with respect to the rotation axis <NUM>, for connecting two screening half-blades 8A, 8B of the same screening blade <NUM>.

According to an embodiment, the screening shaft <NUM> defines a plurality of pairs of equally spaced positioning holes <NUM> along the screening shaft <NUM>.

According to an embodiment of the invention, the positioning and fastening means <NUM> comprise a half-sleeve <NUM> connected to the screening half-blade 8A, 8B.

The half-sleeve <NUM> defines an internal half-sleeve wall <NUM> abutting against the screening shaft <NUM>, an external half-sleeve wall <NUM> facing the connection wall <NUM> of the screening half-blade 8A, 8B, two semi-circumferential end walls <NUM>, and two longitudinal edge walls <NUM>.

According to an embodiment, the half-sleeve <NUM> defines a through hole <NUM>, extending between the internal half-sleeve wall <NUM> and the external half-sleeve wall <NUM>, for accommodating the pin <NUM>.

The through hole <NUM> is defined at the positioning hole <NUM> of the screening shaft <NUM>.

Further, the pin <NUM> extends through the positioning hole <NUM> and the through hole <NUM> so as to connect the half-sleeve <NUM> to the screening shaft <NUM>.

According to an embodiment, the through hole <NUM> and the pin <NUM> are configured so that the pin <NUM> protrudes beyond the internal half-sleeve wall <NUM>, but so that a total release of the pin <NUM> through the semi-cylindrical wall <NUM> is prevented.

According to an embodiment, a plurality of screening half-blades 8A, 8B are connected to the same half-sleeve <NUM>, positioned parallel to each other.

According to an embodiment (<FIG>), the half-sleeve <NUM> defines a plurality of through holes <NUM> arranged in a direction longitudinal to the half-sleeve <NUM>, parallel to the rotation axis <NUM>.

Advantageously, a half-sleeve <NUM> configured in this manner allows the connection to a greater number of screening half-blades 8A, 8B, for example six to twenty screening half-blades 8A, 8B.

According to an embodiment, the positioning and fastening means <NUM> comprise a stop plate <NUM>.

According to an embodiment, the stop plate <NUM> is positioned in abutment against the pin <NUM>. Preferably, the stop plate <NUM> is positioned against the external half-sleeve wall <NUM>.

The stop plate <NUM> prevents a possible release of the pin <NUM> through the external half-sleeve wall <NUM>.

According to an embodiment, the connection wall <NUM> of the screening half-blade 8A, 8B defines a first shaped profile <NUM> at the stop plate <NUM>.

The first shaped profile <NUM> is configured to allow for positioning the stop plate <NUM>, preferably at the pin <NUM>, and to constrain the stop plate <NUM> by means of shape coupling.

Specifically, the first shaped profile <NUM> is configured to allow for an insertion and positioning of the stop plate <NUM> along a direction parallel to the rotation axis <NUM>, and to constrain the stop plate <NUM> via a shape coupling, preventing movements of the stop plate <NUM> in directions orthogonal to the rotation axis <NUM>.

According to an embodiment, the stop plate <NUM> defines walls converging in a longitudinal direction. Such convergence simplifies the insertion of the stop plate <NUM> into the first shaped profile <NUM>.

According to an alternative embodiment, the stop plate <NUM> defines planar and parallel walls.

According to the embodiment in which each half-sleeve <NUM> defines a plurality of through holes <NUM> (<FIG>), a plurality of stop plates <NUM>, one after the other, is positionable in abutment against the external half-sleeve wall <NUM> so as to prevent any release of the pins <NUM>. According to this embodiment, a plurality of comb-like inserts <NUM>, one after the other, is also positionable in connection with the plurality of screening half-blades 8A, 8B. In particular, the plurality of comb-like inserts <NUM> are interposable between the plurality of screening half-blades 8A, 8B and the plurality of stop plates <NUM>. According to this embodiment, a plurality of clamping members <NUM>, preferably circular clamps <NUM>, are connectable at the ends of each half-sleeve <NUM>, at a respective clamping seat <NUM>, for clamping the plurality of screening half-blades 8A, 8B at a predetermined connection position. Naturally, it is foreseeable to implement in this embodiment all other connection and fastening means <NUM> so far and hereinafter described, as they are compatible with this embodiment.

According to an embodiment, each stop plate <NUM> of the plurality of stop plates <NUM> defines at least one lightening slot <NUM>.

According to an embodiment, the connection wall <NUM> defines a connecting portion <NUM> between the first shaped profile <NUM> of the screening half-blade 8A, 8B and hooking protrusions <NUM> of the screening half-blade 8A, 8B (<FIG>). Advantageously, the connecting portion <NUM> does not form sharp edges.

According to an embodiment, the connecting portion <NUM> defines, between a hooking protrusion <NUM> and the first shaped profile <NUM>, a monotonic curve with respect to the radial direction R-R.

According to an alternative embodiment, the screening shaft <NUM> defines a polygonal external wall.

Further, the internal half-sleeve wall <NUM> defines a polygonal counter-wall configured to obtain a shape coupling with the external polygonal wall of the screening shaft <NUM> to allow torque transfer between the screening shaft <NUM> and the half-sleeve <NUM>.

According to an alternative embodiment (<FIG>), the screening half-blade 8A, 8B defines a polygonal counter-wall configured to obtain a shape coupling with the polygonal external wall of the shaft <NUM> to allow a torque transfer between the screening shaft <NUM> and the screening half-blade 8A, 8B.

According to an embodiment, the polygonal counter-wall is formed by the connection wall <NUM> of the screening half-blades 8A, 8B, at hooking protrusions <NUM> formed by the connection walls <NUM>.

According to an embodiment, the at least one screening half-blade 8A, 8B is connected to the half-sleeve <NUM> by an undercut connection.

An undercut connection provides high mechanical strength, which allows the screening blades <NUM> to screen and crush debris material effectively and easily.

According to an embodiment, the half-sleeve <NUM> defines at least one pair of hooking slots <NUM> extending between the internal half-sleeve wall <NUM> and the external half-sleeve wall <NUM> and defined opposite each other at opposite longitudinal edge walls <NUM> of the half-sleeve <NUM>.

According to this embodiment, the connection wall <NUM> of the screening half-blade 8A, 8B forms two hooking protrusions <NUM> configured to be insertable within the hooking slots <NUM>.

Preferably, the hooking slots <NUM> and the hooking protrusions <NUM> obtain an undercut coupling that prevents a movement of the screening half-blade 8A, 8B in a direction parallel to the rotation axis <NUM>.

According to an embodiment, the connection of a screening half-blade 8A, 8B to the half-sleeve <NUM> requires inserting a first hooking protrusion <NUM> into a hooking slot <NUM> (<FIG>). Next, the first hooking protrusion <NUM> is further inserted into the hooking slot <NUM> so as to protrude into the half-sleeve <NUM> (<FIG>). This subsequently allows the second hooking protrusion <NUM> to be inserted into the opposite hooking slot <NUM> (<FIG>). Subsequently, the first and second hooking protrusions <NUM> are positioned to make an undercut connection with the half sleeve <NUM>, with the hooking protrusions <NUM> not protruding into the half-sleeve <NUM> (<FIG>).

According to an embodiment, the half-sleeve <NUM> defines a plurality of pairs of hooking slots <NUM> for connecting a plurality of screening half-blades 8A, 8B to the half-sleeve <NUM>.

According to an embodiment, the half-sleeve <NUM> defines four pairs of hooking slots <NUM>, for connecting four screening half-blades 8A, 8B, arranged parallel to each other and orthogonal to the rotation axis <NUM>. Alternatively, the half-sleeve <NUM> defines five pairs of hooking slots <NUM>, for connecting five screening half-blades 8A, 8B, arranged parallel to each other and orthogonal to the rotation axis <NUM>.

According to a further embodiment, the screening half-blades 8A, 8B connected to the same half-sleeve <NUM> have different extensions in the direction R-R.

According to an embodiment, the positioning and fastening means <NUM> comprise a comb-like insert <NUM>, forming a plurality of teeth <NUM>.

The comb-like insert <NUM> is connected to the plurality of screening half-blades 8A, 8B connected to a same half-sleeve <NUM>.

According to an embodiment (<FIG>), the positioning and fastening means <NUM> comprise a comb-like insert <NUM>, which is formed in two longitudinally separated pieces, and a wedge <NUM> insertable between the two pieces of the comb-like insert <NUM>.

Advantageously, the wedge <NUM> is configured to widen the two pieces of the comb-like insert <NUM> by biasing them against the connection wall <NUM> of the screening half-blades 8A, 8B.

Preferably, the wedge <NUM> has a convergent profile in a longitudinal direction, which facilitates its insertion between the first piece and the second piece of the comb-like insert <NUM> and the subsequent widening between the first piece and the second piece of the comb-like insert <NUM>.

According to an embodiment, the wedge <NUM> inserted between the two pieces of the comb-like insert <NUM> is positioned against the pin <NUM>, so as to prevent any release of the pin <NUM> through the external half-sleeve wall <NUM>.

According to an embodiment, the comb-like insert <NUM> is positioned at the stop plate <NUM> and interposed between the stop plate <NUM> and the connection wall <NUM>.

According to an alternative embodiment, the comb-like insert <NUM> is positioned against the external half-sleeve wall <NUM> of the half-sleeve <NUM>.

According to an embodiment, the connection wall <NUM> of the screening half-blade 8A, 8B defines a second shaped profile <NUM> at the comb-like insert <NUM>.

The second shaped profile <NUM> is configured to allow for positioning the comb-like insert <NUM>, and to constrain the comb-like insert <NUM> by means of a shape coupling between the second shaped profile <NUM> and the plurality of teeth <NUM>.

Specifically, the second shaped profile <NUM> is configured to allow for an insertion and positioning of the comb-like insert <NUM> along a direction parallel to the rotation axis <NUM>, and to obtain a subsequent engagement between the teeth <NUM> and the second shaped profile <NUM> of each screening half-blade 8A, 8B of the plurality of screening half-blades 8A, 8B connected to a same half-sleeve <NUM>.

According to the embodiment comprising the comb-like insert <NUM> formed in two longitudinally separated pieces and a wedge <NUM>, the second shaped profile <NUM> is configured to allow an insertion and positioning of the first piece and the second piece of the comb-like insert <NUM> along a direction parallel to the rotation axis <NUM>, and to obtain a subsequent engagement between the teeth <NUM> of the first piece and the second piece of the comb-like insert with the second shaped profile <NUM>. The engagement of the first piece and second piece of the comb-like insert <NUM> with the second shaped profile <NUM> defines a slot for inserting the wedge <NUM> between the first piece and second piece of the comb-like insert <NUM> (<FIG>).

The comb-like insert <NUM> helps stabilize the positioning of the plurality of screening half-blades 8A, 8B connected to a same half-sleeve <NUM>.

According to an embodiment (<FIG>), the positioning and fastening means <NUM> comprise a plurality of stop forks <NUM> configured to obtain a shape coupling with the plurality of screening half-blades 8A, 8B connected to a same half-sleeve <NUM>.

According to an embodiment, each stop fork <NUM> of the plurality of stop forks <NUM> is shaped in the form of an "H" and is configured to engage with the connection wall <NUM> of a corresponding screening half-blade 8A, 8B.

According to an embodiment, the plurality of stop forks <NUM> are positioned at the stop plate <NUM>, interposed between the stop plate <NUM> and the connection wall <NUM> of the screening half-blades 8A, 8B connected to a same half-sleeve <NUM>.

According to this embodiment, the second shaped profile <NUM> is configured to allow for an insertion and positioning of each stop fork <NUM> along a direction parallel to the rotation axis <NUM>, to obtain a subsequent engagement between each stop fork <NUM> and each respective shaped profile <NUM>, and to allow for the subsequent insertion of the stop plate <NUM> (<FIG>).

According to an embodiment, each screening half-blade 8A, 8B is connected to a half-sleeve <NUM> by means of only the stop plate <NUM> or only the comb-like insert <NUM>.

According to a further embodiment, each screening half-blade 8A, 8B is connected to a half-sleeve <NUM> by means of only the stop plate <NUM> and the comb-like insert <NUM> (<FIG>). Advantageously, such a configuration requires neither the use of a pin <NUM> nor the provision of a through hole <NUM> within the half-sleeve <NUM>, nor the provision of positioning holes <NUM> on the screening shaft <NUM>.

According to an embodiment, each pair of opposing half-sleeves <NUM> and the screening shaft <NUM> obtains a force coupling with each other.

The force coupling is obtained by torque transfer facilitating means formed at the internal half-sleeve walls <NUM> and/or the screening shaft <NUM>.

According to an embodiment, the torque transfer facilitating means are, for example, roughnesses, ridges, or knurls defined on the internal half sleeve walls <NUM> and/or on the screening shaft <NUM>.

According to an embodiment, the connecting and fastening means <NUM> comprise a clamping member <NUM> configured to tighten a screening half-blade 8A, 8B in the predefined connection position <NUM>.

According to an embodiment, the clamping member <NUM> is a circular clamp <NUM>.

The circular clamp <NUM> comprises a half-clamp with smooth holes 34A and a half-clamp with threaded holes 34B, positioned opposite each other with respect to the screening shaft <NUM>.

Further, the circular clamp <NUM> comprises clamping screws <NUM> adapted to screw the half-clamp with smooth holes 34A against the half-clamp with threaded holes 34B.

According to an embodiment, the half-clamp with smooth holes 34A and the half-clamp with threaded holes 34B are clamped against each other in a direction orthogonal to the coupling direction of two screening half-blades 8A, 8B of the same screening blade <NUM>.

This configuration strengthens the clamping of the screening blades <NUM> to the screening shaft <NUM>.

According to a further embodiment, the circular clamp comprises two half-clamps with smooth holes 34A positioned opposite to each other with respect to the screening shaft <NUM>.

According to this embodiment, the two opposite circular half-clamps with smooth holes 34A are tightened against each other with bolts.

According to an embodiment, the circular clamp <NUM> is positioned at the semi-circumferential end walls <NUM> of a half-sleeve <NUM> and is configured to tighten the semi-circumferential end walls <NUM> against the screening shaft <NUM>.

According to an embodiment of the invention, the half-sleeve <NUM> defines a clamping seat <NUM> at each semi-circumferential end wall <NUM>.

The circular clamp <NUM> is positioned in the clamping seat <NUM>.

Positioning the circular clamp <NUM> in the clamping seat <NUM> reduces the exposure of the circular clamp <NUM> to the debris material being screened.

According to an embodiment, the circular clamp <NUM> is positioned in the clamping seats <NUM> of a pair of half-sleeves <NUM> of the same screening blade <NUM>.

A pair of half-sleeves <NUM> means the two half-sleeves <NUM> positioned one opposite the other with respect to the screening shaft <NUM>, and to which the two screening half-blades 8A, 8B of a same screening blade <NUM> are connected, respectively.

Thus, the circular clamp <NUM> clamps the two screening half-blades 8A, 8B of a same screening blade <NUM> against the screening shaft <NUM>.

According to an embodiment, a plurality of pairs of half-sleeves <NUM> are positioned against each other along the screening shaft <NUM>, and the circular clamp <NUM> is positioned in the adjacent clamping seats <NUM> of two adjacent pairs of half-sleeves <NUM>.

Thus, only one circular clamp <NUM> is necessary to tighten two adjacent half-sleeves <NUM> against the screening shaft <NUM>.

According to an embodiment, each clamping seat <NUM> defines a coupling recess <NUM>.

The coupling recess <NUM> allows the circular clamps <NUM> to be connected to the clamping seats <NUM> in a predetermined orientation with respect to the screening shaft <NUM> (<FIG>, <FIG>).

According to an embodiment, the plurality of circular clamps <NUM> that tighten the plurality of half-sleeves <NUM> against the screening shaft <NUM> all have the same orientation relative to the screening shaft <NUM>.

According to an embodiment (<FIG>), each pair of half-sleeves <NUM> defines a pair of clamping holes <NUM> at each semi-circumferential end wall <NUM>.

Each pair of clamping holes <NUM> is defined by a pair of through clamping holes 42A defined at the semi-circumferential end wall <NUM> of a half-sleeve <NUM>, and an opposite pair of threaded clamping holes 42B defined in the opposite semi-circumferential end wall <NUM> of the opposite half-sleeve <NUM>. Alternatively, each pair of clamping holes <NUM> is defined by a pair of through clamping holes 42A defined at the semi-circumferential end wall <NUM> of a half-sleeve <NUM> and by an opposite pair of additional through clamping holes 42A defined in the opposite semi-circumferential end wall <NUM> of the opposite half-sleeve <NUM>, and wherein the two opposite half-sleeves <NUM> are clamped against each other by bolts.

According to an embodiment, the clamping holes <NUM> extend through the half-sleeve <NUM> from the external half-sleeve walls <NUM> to the longitudinal edge walls <NUM>.

The half-sleeves <NUM> thus configured are clamped against each other with respect to the screening shaft <NUM> by means of clamping screws <NUM> that may be screwed into the clamping holes <NUM>.

Advantageously, such a configuration of the half-sleeves <NUM> does not require additional clamping means, such as circular clamps <NUM>.

According to an embodiment, the thickness of the half-sleeves <NUM>, i.e., the distance between the external half-sleeve wall <NUM> and the internal half-sleeve wall <NUM>, is at the maximum at the longitudinal edge walls <NUM>, and at the minimum at a median area, i.e., a vertex area, of the half-sleeve <NUM>.

Therefore, the external half-sleeve wall <NUM> has a substantially oval shape.

Advantageously, the oval shape of the external half-sleeve wall <NUM>, in combination with the substantially circular shape of the internal half-sleeve wall <NUM>, obtains an increase in the resistant surface area of the half-sleeve <NUM> precisely at its area most subject to stress.

According to an embodiment (<FIG>), the plurality of pairs of half-sleeves <NUM> connected to a same screening shaft <NUM> comprises at least one end half-sleeve <NUM> connected to an end of the screening shaft <NUM>.

The end half-sleeve <NUM> defines at least one through hole <NUM> for a connection of the end half-sleeve <NUM> to the screening shaft <NUM> by at least one respective pin <NUM>.

Further, the end half-sleeve <NUM> defines a clamping seat <NUM> interposed between the through holes <NUM>.

The clamping seat <NUM> delimits a first end half-sleeve portion <NUM> and a second end half-sleeve portion <NUM>, wherein the first end half-sleeve portion <NUM> faces the end of the screening shaft <NUM>, and the second end half-sleeve portion <NUM> faces opposite the end of the screening shaft <NUM>, and wherein the at least one through hole <NUM> is defined in the first end half-sleeve portion <NUM>, or the at least one through hole <NUM> is defined in the second end half-sleeve portion <NUM>.

Advantageously, the clamping seat <NUM> interposed between the first end half-sleeve portion <NUM> and the second end half-sleeve portion <NUM> prevents a possible release of the stop plate <NUM> positioned at the second end half-sleeve portion <NUM>.

According to an embodiment, the first end half-sleeve portion <NUM> defines an additional through hole <NUM> extending between the internal half-sleeve wall <NUM> and the external half-sleeve wall <NUM>.

According to this embodiment, the stop plate <NUM> positioned at the first end half-sleeve portion <NUM> defines an auxiliary through hole <NUM> at the additional through hole <NUM>.

Further, the positioning and fastening means <NUM> comprise an additional pin <NUM> configured to be insertable through the additional through hole <NUM> and the auxiliary through hole <NUM>, whereby the stop plate <NUM> is constrained to the first portion of the end half-sleeve <NUM>.

Advantageously, the additional pin <NUM> prevents a possible release of said stop plate <NUM> positioned at the first end half-sleeve portion <NUM>.

According to an embodiment, the stop plate <NUM> positioned at the first portion of the end half-sleeve <NUM> defines two auxiliary through holes <NUM>.

Advantageously, two auxiliary through holes <NUM> make the stop plate <NUM> symmetrical.

According to an embodiment, the first end half-sleeve portion <NUM> has a longitudinal extension substantially equal to one half of the longitudinal extension of the second end half-sleeve portion <NUM>.

According to this embodiment, the stop plate <NUM> and the comb-like insert <NUM> positioned at the first end half-sleeve portion <NUM> have a longitudinal extension substantially equal to one half of the longitudinal extension of the stop plate <NUM> and of the comb-like insert <NUM> positioned at the second end half-sleeve portion <NUM>.

According to an embodiment, the screening bucket <NUM> comprises two pinions <NUM>.

Preferably, the pinions <NUM> are positioned at the unloading opening <NUM>.

According to an embodiment, each shaft comprises from one to ten pairs of half-sleeves <NUM>.

Preferably, each shaft comprises eight pairs of half-sleeves <NUM>.

According to an embodiment, the screening blades <NUM> have different radial extensions and are positioned on the two pinions <NUM> in such a way as to make a substantially wavy or "zig-zag" passage <NUM> between the two pinions <NUM>.

A passage <NUM> configured in this manner increases the efficiency of the screening process.

According to an embodiment, five screening blades <NUM> are connected to each pair of half-sleeves <NUM>, of which two screening blades <NUM> of lesser radial extension are arranged at two ends of the half-sleeves <NUM>, one screening blade <NUM> of greater radial extension is positioned at a median area of the half-sleeves <NUM>, and two screening blades <NUM> of radial extension intermediate between the lesser and greater radial extension are each interposed between a screening blade <NUM> of lesser radial extension and the screening blade <NUM> of greater radial extension.

According to an embodiment, of the five screening blades <NUM> connected to a pair of half-sleeves <NUM>, the screening blade <NUM> with greater radial extension has a greater thickness than the thickness of the screening blades <NUM> with lesser radial extension and the screening blades <NUM> with intermediate radial extension (<FIG><FIG>). Preferably, the thickness of the screening blade <NUM> with greater extension is substantially twice the thickness of the screening blades <NUM> with lesser radial extension and the screening blades <NUM> with intermediate radial extension.

According to an embodiment, three screening blades <NUM> are connected to two half-sleeves <NUM> each defining five pairs of hooking slots <NUM>, wherein two screening blades <NUM> with lesser radial extension are arranged at two ends of the half-sleeves <NUM> and one screening blade <NUM> with greater radial extension is positioned at a median area of the half-sleeves <NUM> (<FIG>).

Advantageously, said configuration obtains an increased clearance between the screening blade <NUM> with greater radial extension and the screening blades <NUM> with lesser radial extension.

According to an embodiment (<FIG>), the "zig-zag" passage <NUM> between a first and a second screening shaft <NUM> that face each other is made by placing two screening blades <NUM> of greater radial extension at the two respective ends of the first screening shaft <NUM>, and by positioning two screening blades <NUM> of lesser radial extension at two respective ends of the second screening shaft <NUM> facing the first screening shaft <NUM>.

According to an embodiment (<FIG>), the "zig-zag" passage <NUM> between a first and a second screening shaft <NUM> that face each other is obtained by placing an end half-sleeve <NUM>, as previously described, at an end of the first screening shaft <NUM> facing a first wall of the box-shaped bucket body <NUM>, and positioning an end half-sleeve <NUM> at an end of the second screening shaft <NUM> facing a second wall of the box-shaped bucket body <NUM>, wherein the first wall of the box-shaped bucket body <NUM> is opposite the second wall of the box-shaped bucket body <NUM>.

According to an embodiment, the end half-sleeves <NUM> are positioned at the ends of the same screening shaft <NUM>, respectively.

According to this embodiment, a screening blade <NUM> of greater radial extension is positioned in each end half-sleeve <NUM>, facing the box-shaped bucket body <NUM> (<FIG>).

According to a further aspect of the invention, a screening blade <NUM> is applicable to a screening shaft <NUM> of a screening bucket <NUM> as described above, and comprises two screening half-blades 8A, 8B configured to be connectable to the screening shaft <NUM>.

Further, each screening half-blade 8A, 8B is connectable to the screening shaft <NUM> approaching said screening shaft <NUM> along the radial direction R-R.

Further, each screening half-blade 8A, 8B is connectable to the screening shaft <NUM> via a positive mechanical connection <NUM>.

Further, the positive mechanical connection <NUM> is reversible.

According to a further aspect of the invention, a set of screening blades <NUM>, applicable to a screening shaft <NUM> of a screening bucket <NUM> as previously described, comprises a plurality of screening blades <NUM>, wherein each screening blade <NUM> comprises two screening half-blades 8A, 8B configured to be connectable to the screening shaft <NUM>.

Further, the positive mechanical connection <NUM> is reversible to allow said each half-blade 8A, 8B to be disconnected from said screening shaft <NUM>.

According to a further aspect of the invention, a method for assembling a screening blade <NUM> to a screening shaft <NUM> of a screening bucket <NUM> as previously described comprises the steps of:.

According to an embodiment, connecting the first of the two screening half-blades 8A to the screening shaft <NUM> comprises the steps of:.

Further, connecting the second of the two screening half-blades 8B to the screening shaft <NUM> comprises the steps of:.

Further, connecting the two screening half-blade 8A, 8B via a mechanical coupling <NUM>, wherein the mechanical coupling <NUM> is reversible, comprises the step of:.

Claim 1:
A screening bucket (<NUM>) for handling debris material, particularly earth, comprising a box-shaped bucket body (<NUM>) defining a loading compartment (<NUM>) and an unloading opening (<NUM>), said screening bucket (<NUM>) further comprising a screening unit (<NUM>) configured to screen debris material,
said screening unit (<NUM>) comprising:
- at least one screening shaft (<NUM>) rotatable about a rotation axis (<NUM>);
- at least one pinion (<NUM>), mounted on the at least one screening shaft (<NUM>), and comprising a plurality of screening blades (<NUM>) connected to the screening shaft (<NUM>) and extending along a radial direction (R-R) orthogonal to said rotation axis (<NUM>);
- drive and transmission means (<NUM>), configured to generate and transmit a rotary motion to at least one pinion (<NUM>);
characterized in that at least one screening blade (<NUM>) of the plurality of screening blades (<NUM>) comprises two screening half-blades (8A, 8B) connected to the screening shaft (<NUM>),
wherein each half-blade (8A, 8B) is connected to the screening shaft (<NUM>) approaching said screening shaft (<NUM>) along said radial direction (R-R),
wherein each half-blade (8A, 8B) is connected to the screening shaft (<NUM>) by means of a positive mechanical connection (<NUM>),
and wherein said positive mechanical connection (<NUM>) is reversible to allow said each half-blade (8A, 8B) to be disconnected from said screening shaft (<NUM>).