Screening device

Abstract

Screening device(1) comprising a tubular box-shaped body (100) having two opposing sides (105') (105'') connected by an opposing first plate (103') and an opposing second plate (108) that delimit a first opening (102) and a second opening (104) engaged fully by a plurality of screening members (106') (106''); each screening member (106') (106") comprising a shaft (1060) that carries a plurality of moving members (1062) arranged spaced between the first and second sides (105') (105'') and provided with a plurality of lobes (10620) uniformly distributed peripherally; an actuator (110) being carried by the box-shaped body (100) to carry in rotation the screening members (106') (106'') so that, in use, each screening member (106') (106") envelopes an ideal first cylinder (C1) of a determined diameter, through the lobes (10620) of the respective moving members (1062); the set of the first cylinders (C1) envelopes an ideal second cylinder (C2) contained fully inside the box-shaped body (100).

Description

[0001] The present invention can be used when it is necessary to treat materials coming from excavations or demolitions, in order to separate sand, soil or similar from debris of various nature. In particular, the present invention relates to a screening device comprising a container arranged to be coupled to an end portion of an articulated arm of an operating machine so as to be easily swung in order to be practical to use. In more detail, the present invention relates to a screening device comprising a container shaped to be coupled to an end portion of an articulated arm of an operating machine and to optimise the step of screening the material contained.DESCRIPTION OF THE PRIOR ART

[0002] In the sector of separation of aggregates from soil, sand or gravel, it is known to use screening devices comprising containers, also called tanks, with a substantially prismatic box shape, closed above and below by longitudinal plates, where the upper plate has centrally a gripping portion and the lower one has a front side delimited by a blade, the purpose of which is to cut the soil to facilitate the loading operations of the material to be screened inside the tank. In particular, the tank has a first opening on the front through which the loading operations of the material take place and a second opening on the back engaged totally by a screening device, provided with a plurality of rotatable screening members. The tank comprises laterally respective sides that connect the longitudinal plates and serve as a support for the screening members, each of which comprises a shaft oriented transversely with respect to the second opening and rigidly supporting a plurality of moving members for moving the material contained inside the tank. Said moving members are equal and arranged longitudinally spaced, which approximates, rounded up, the transverse dimension of each moving member. A hydraulic drive unit is provided that places in rotation the shafts of the screening members through the transmissions to the parallel axes, normally belt or chain, determining rotations in the same direction of said screening members. Furthermore, the moving members of two adjacent screening members are staggered, so that the peripheral radial portions of the moving members of each screening member engage the free space between the moving members of every other adjacent screening member. These moving members can be constructed, as in the case of the company Simex, of metallic discs provided with a plurality of lobes uniformly distributed around the relative shaft or, as in the case of the so-called "e-buckets" of the company Gyru-Star, have a plurality of fingers made of a plastic material. In both cases, the peripheral spaces between the lobes, or between the fingers, are engageable in use by soil, sand or gravel that are separate or detached from the excavation waste moved (as said by the lobes or by the fingers), so that the soil, sand or gravel is continuously dischargeable from the tank in which, in contrast, the excavation waste is retained.

[0003] The axes of the shafts are coplanar and the upper and lower longitudinal plates are inclined with respect to each other so that the first opening has a greater extension than the second opening. This structural feature has a drawback, which occurs above all in tanks of small dimensions: the excavation waste tends to be arranged "bridged" between the inner faces of the upper and lower plates, interrupting the path of material such as soil, sand or gravel to be discharged, which therefore remains inside the tank. In order to avoid this, a continuous shaking action of the tank controlled by the operator is necessary. The production of continuous vibrations of the tank corresponds with this, the consequences of which are negative both for the device and the equipment supporting it and for the operator.

[0004] In other cases, with the intention of increasing the productivity of the screening devices of the type described, some manufacturers have decided to construct tanks with a higher volume. This solution has made it necessary to considerably expand the distance between the two plates that delimit the tank of the screening device above and below and to install a significant number of screening members, as it is not reasonable to increase the radial dimensions of the respective moving members. Considering that the thrust components that the portions of the moving members exert on the material to be screened are substantially horizontal, there is a progressive shifting of the material contained in the tank from the side of the plate towards which these components are oriented. This gradually decreases discharging of the screening members adjacent to the opposite plate, with a reduction in operation of the device and uneven wear of the moving members of the various screening members, which is a particularly important operating drawback, accompanied by costs that it would be preferable to avoid. The same happens in the case of screening members whose axes are arranged in a lying position that has a slight concavity towards the first opening, as in the case of the screening buckets of the company MB S.p.A.

[0005] In order to increase the screening capacity of the devices described here, some manufacturers, such as Gyru-Star, have conceived to arrange the shafts of the screening members on two flat sections arranged as an elbow bend, one of which engages a part of the upper plate, which is positioned vertically when the screening device is operating. In this case, each screening member that engages the upper plate is raised with respect to the others and its own action produces the projection of screened material laterally, with consequent expansion of the discharge zone of the screening device and, therefore, of the buffer zone for the operators who are working around said screening device.

[0006] Based on what is described above, the screening devices structured as described above have many drawbacks.

[0007] Based on what is described above, the problem of constructing a screening device with a high operating capacity in relation to the dimensions of the respective tank, intrinsically safe, with an optimised number of components and therefore with reduced purchase cost and maintenance, is currently unresolved, and represents an interesting challenge for the applicant, as well as being the object of the present invention.

[0008] In consideration of the situation described above, it would be desirable to have a screening device that, in addition to limiting and possibly overcoming the typical drawbacks of the prior art described above, defines a new quality standard for these types of equipment for screening excavation material.SUMMARY OF THE PRESENT INVENTION

[0009] The present invention can be used when it is necessary to treat materials coming from excavations or demolitions, in order to separate sand, soil or similar from debris of various nature. In particular, the present invention relates to a screening device comprising a container arranged to be coupled to an end portion of an articulated arm of an operating machine so as to be easily swung in order to be practical to use. In more detail, the present invention relates to a screening device comprising a container shaped to be coupled to an end portion of an articulated arm of an operating machine and to optimise the step of screening the material contained.

[0010] The drawbacks indicated above are solved by the present invention in accordance with at least one of the claims that follow.

[0011] According to several embodiments of the present invention a screening device is implemented, comprising a tubular box-shaped body extending in an established direction, having two opposing sides connected by an opposing first plate and by an opposing second plate that delimit a first opening and a second opening engaged fully by a plurality of screening members, each of which comprises a shaft carried from said sides in a freely rotating manner transversely to said direction around a respective axis; each said shaft carries a plurality of moving members arranged spaced between said first and second sides and provided with a plurality of lobes uniformly distributed peripherally; an actuator being carried by said box-shaped body between said sides to carry in rotation said screening members so that, in use, each of said screening members envelops an ideal first cylinder of a first diameter determined through said lobes; the set of said first cylinders enveloping an ideal second cylinder contained fully inside said box-shaped body; said second cylinder being positioned at a distance from said first plate that measures a length lower than or equal to the diameter of said first cylinder and, with respect to said second plate, at a distance that measures a length comprised between one and one and a half times said first diameter.

[0012] According to an embodiment as described above, said axes of said shafts envelop a surface shaped similarly to an ideal third cylinder of a diameter that approximates, rounded down, a distance between the first plate and said second plate.

[0013] According to an embodiment as described above, said first plate and said second plate are parallel to said direction, so as to delimit a prism-shaped screening volume upstream of said screening members.

[0014] According to an embodiment as described above, a first screening member of said plurality of screening members is mechanically connected to said actuator through a first transmission unit carried by said box-shaped body to a first side of said two sides in order to be controlled in axial rotation; said first unit having parallel axes and the remaining screening members of said screening members being connected to said first screening member through a second transmission unit having parallel axes carried by said box-shaped body to a second side of said two sides. According to an embodiment as described above, said first transmission unit comprises a first flexible transmission member mechanically coupled to said first screening member and to said actuator in respective end positions. According to an embodiment as described above, said second transmission unit comprises a second flexible transmission member mechanically coupled to said first screening member and to each of said remaining screening members in respective end positions.

[0015] According to an embodiment as described above, respective tensioning members are associated with said first flexible transmission member and said second flexible transmission member.

[0016] According to an embodiment as described above, said moving members are arranged spaced between said first and second sides through the interposition of spacer rings; end clamping means being provided in combination with said shaft for maintaining said moving members packed together with said rings.

[0017] According to an embodiment as described above, each said shaft is of the prismatic type and has a constant transverse section shaped like a regular polygon; each said moving member having a hub with a section that is the negative copy of a transverse section of said shaft, in order to be axially mounted sliding with the respective said lobes facing or helical or angularly staggered, as desired.

[0018] According to an embodiment as described above, said first flexible transmission member and said second flexible transmission member comprise, respectively, a first chain and a second chain; each of said remaining screening members carrying a second cogwheel in an end position to said second side; said first screening member carrying a first cogwheel for each respective end position, in order to mechanically couple with said first chain on said first side and with said second chain on said second side. According to an embodiment as described above, said second cogwheels are coupled to the respective said shaft so as to be interchangeable, in order to change, as desired, a transmission ratio with respect to said first screening member / actuator.

[0019] According to an embodiment as described above, said actuator is of the hydraulic type and is mechanically connected to said first screening member; a hydraulic circuit being provided to power said actuator and comprising a slide valve hydraulically connected to said actuator and switchable in the case of overpressure; an overpressure sensor being provided to control a relative automatic switching of said actuator.

[0020] According to an embodiment as described above, a first compartment containing said first transmission unit and closed by a first cover is associated with said first side; a second compartment containing said second transmission unit and closed by a second cover being associated with said second side.

[0021] According to an embodiment as described above, a lubrication unit is provided, comprising a feed conduit provided with a discharge opening associated with each said first cogwheel and each said second cogwheel in order to lubricate them automatically.

[0022] According to an embodiment as described above, said second plate is delimited by a blade on the side of said first opening.

[0023] Any further embodiments of the present invention are defined by the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Further characteristics and advantages of the screening device according to the present invention will become clearer from the following description, stated with reference to the appended figures, which illustrate at least one example of a non-limiting embodiment, in which identical or corresponding parts of said screening device are identified by the same reference numbers. In detail: Figure 1 is a schematic perspective view of a screening device according to the present invention, arranged in a first position and represented from a first viewpoint; Figure 2 is a schematic perspective view of the screening device of the figure represented from a second viewpoint; Figure 3 is a front view of Figure 1 according to the present invention; Figure 4 is a schematic perspective view of the device of Figure 1 represented in a second position from a third lateral viewpoint; Figure 5 is a schematic perspective view of the screening device of Figure 4 represented from a fourth lateral viewpoint; Figure 6 shows Figure 5 with parts removed for clarity; Figure 7 is a view in side elevation of Figure 4, with parts removed for clarity; Figure 8 is an enlarged view, with parts removed for clarity, of a portion of Figure 7; Figure 9 is a schematic perspective view of a construction detail of Figure 1; Figure 10 is a schematic perspective view of Figure 2 with parts removed for clarity; Figure 11 is a view from a viewpoint obtained from Figure 3, with parts removed for clarity. DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0025] Before describing in detail the preferred embodiments of the present invention or details of it, it is considered useful to specify that the relative scope of protection is not limited to the particular embodiments described here below. The disclosure and description in this document are illustrative and explanatory of one or more currently preferred embodiments and variants, and it will be clear to people skilled in the art that various changes in the design, in the organisation, in the order of operation, in the means of operation, in the structures of the equipment and position, in the method and use of mechanical equivalents could be made without being extraneous to the spirit of the invention.

[0026] Furthermore, it must be understood that the purpose of the appended figures is to illustrate and clearly disclose currently preferred embodiments to one of the people skilled in the art, but that they are not drawings that illustrate how such embodiments should be performed in reality or actual representations of end products; on the contrary, these figures could comprise simplified conceptual views to facilitate understanding or to allow an easier and quicker explanation to be provided. Furthermore, the relative dimensions and the arrangement of the components could differ from the ones shown and still function in the spirit of the invention.

[0027] In any case, it will be clear that various directions, such as "upper", "lower", "left", "right", "front", "rear" and so on, are performed only with respect to the explanation, in combination with the drawings, and that the components could be oriented in a different way, for example during transport and production, and also during operation. Since many different and separate embodiments could be made within the scope of the concepts taught here, and since there are multiple changes that could be made to the embodiments described here, it must be understood that the details provided below should be interpreted as illustrative and not limiting the spirit of the invention. In Figure 1, the number 1 denotes, in its entirety, a screening device, comprising a tubular box-shaped body 100 extending in an established direction 10, having two opposing sides 105, parallel to the direction 10 and connected by an opposing first upper plate 107 and an opposing second lower plate 108 that delimit, as a body, a first opening 102 (Figures 1 and 2) that, based on what is described above, is delimited by a perimeter with a rectangular shape, therefore polygonal, and a second opening 104 (Figures 4-6). The latter is fully engaged by a plurality of screening members 106, each of which comprises a shaft 1060 carried by the sides 105 so as to be freely rotatable transversely to said direction 10 around a respective axis 1061. The first plate 107 has centrally a gripping portion 1070 that carries an adaptor 1072 for a mechanical articulated arm (known and not illustrated) and the second plate 108 is delimited frontally (in Figures 1-3) by a blade 1080 usable to excavate material to feed to the plurality of screening members 106.

[0028] With reference to Figure 7, the first plate 107 and the second plate 108 delimit, together with the sides 105, a volume V engageable by the material to be screened contained, in use, by the box-shaped body 100 above the screening members 106.

[0029] According to Figures 1 to 6, each shaft 1060 carries a plurality of moving members 1062 arranged spaced between the two sides 105, where, with particular reference to Figure 9, each moving member 1062 is provided with a plurality of lobes 10620 uniformly distributed peripherally. The moving members 1062 are arranged spaced between the ends of the shaft 1060 and, in use, between the two sides 105, through the interposition of spacer rings 1064. The width of each ring 1064 approximates, rounded up, the thickness of each moving member 1062. As clear from the appended figures, this structural choice allows the screening members 106 to be arranged at a lower transverse distance to the maximum radius of the lobes 10620 of the moving members 1062. Furthermore, each screening member 106 is provided with respective end clamping means 1066 in combination with said shaft 1060, where the purpose of such clamping means 1066 is to maintain the corresponding moving members 1062 packed together with the rings 1064.

[0030] It could be useful to specify that each shaft 1060 is of the prismatic type and has a constant transverse section shaped like a regular polygon. Each moving member 1060 and each ring 1064 have respectively a hub 1066, known and not shown with sections that are the negative copy of a section of said shaft 1060 transverse to the axis 1061, in order to be axially mounted sliding. In particular, through such prismatic coupling, the moving members 1062 can be mounted on the respective shaft 1060 with the respective lobes 10620 facing longitudinally, arranged helical or angularly staggered, as desired, so as to give specific functions to the respective screening member 106, which take the type of material to be screened into account.

[0031] According to figure 7, the screening device 1 further comprises a hydraulic actuator 110 carried by the box-shaped body 100 above the screening members 106 between the two sides 105 inside a transverse compartment 101 delimited by a protective metal sheet 103 that is carried by the first plate 107. The metal sheet 103 has a third plate 103' that is facing and parallel to the second plate 108, connects the sides 105 and, based on what is described above, reduces the volume V on the side of the first opening 102 by a portion corresponding with the blade 1080. In addition, the third plate 103' carries below a comb 103", therefore facing a first screening member 106' of the screening members 106 facing the first plate 107, with the effect of delimiting a space under the transverse compartment 101 between the screening member 106' and the first plate 107. Therefore, the first plate 103' delimits the volume V on the opposite side to the second plate 108 upstream of the screening members 106, therefore above the first screening member 106'; therefore, based on what is described above, the volume V inside the box-shaped body 100 has a prismatic shape with respect to a transverse direction to the direction 10 and to the sides 105.

[0032] The purpose of the actuator 110 is to carry in rotation the screening members 106 interchangeably in a clockwise or anticlockwise direction so that, in use, each of them envelopes an axisymmetric body with the top portions of the lobes 1062 thereof, an axisymmetric body that will be an ideal first cylinder C1 of an established first diameter, the line of which is indicated in Figures 7-9 and represented with the dashed-dotted line in Figure 8, if the moving members 1062 are sized in an identical manner, so that the top portions of the lobes 1062 have the same radial distance from the axis of the corresponding screening member 106. In addition, the set of the first cylinders C1 envelopes a surface geometrically shaped so that an ideal second cylinder C2 represents it in an approximate manner, where the line of the second cylinder C2 is visible in Figure 8, represented with the dashed-dotted line. The second cylinder C2 is fully contained inside the box-shaped body 100 and the axes 1061 of the shafts 1060 of the screening members 106 envelop a surface geometrically shaped so that an ideal third cylinder C3 represents it in an approximate manner, where the line of the third cylinder C3 is visible in Figure 8, represented with the dashed-dotted line.

[0033] Again with reference to Figures 7 and 8, the second cylinder C2 is positioned at a distance from the third plate 103', or an extension thereof towards the underlying first screening member 106', which measures a length lower than or equal to the diameter of the first cylinders C1 and, if these were to be different, lower than or equal to the diameter of the first cylinder C1 with the highest diameter; furthermore, the second cylinder C2 is positioned at a distance from the second plate 108 comprised between one and one and a half times the measurement of the diameter of a first cylinder C1, in the sense indicated here above in the case of a first cylinder C1 with the highest diameter. Furthermore, the third cylinder C3 measures a diameter that approximates, rounded down, a distance between the second plate 108 and the third plate 103'.

[0034] In any case, it should be specified that the scope of protection of the present invention also comprises an embodiment of the screening device 1 wherein the axes 1061 are contained inside a known first cylindrical strip, not shown, which contains the third cylinder C3 and, consequently, allows a second cylindrical strip to be traced, inside which the second cylinder C2 is contained. With particular reference to Figure 4, a first screening member 106' of the screening members 106 is mechanically connected to the actuator 110 through a first transmission unit 120 carried by the box-shaped body 100 on the side of a first side 105' of the two sides 105, in order to be controlled in axial rotation. Said first member 106' has not been shown on Figure 4, where only the position of this component with respect to the remaining screening members 106'' and to the box-shaped body 100 is shown, through a respective dotted line. The first unit 120 is of the parallel axis type and the remaining screening members 106'' are connected to the first screening member 106' through a second transmission unit 122 visible in Figure 5, which also has parallel axes, carried by the box-shaped body 100 on the side of a second side 105" of the two sides 105.

[0035] Again with particular reference to Figure 4, the first transmission unit 120 comprises a first flexible transmission member 1200 mechanically coupled to the first screening member 106' and to the actuator 110 in respective end positions inside a first compartment 1050.

[0036] With particular reference to Figure 5, the second transmission unit 122 comprises a second flexible transmission member 1220 mechanically coupled to the first screening member 106' and to each of the remaining screening members 106'' in respective end positions inside a second compartment 1052.

[0037] With particular reference to Figures 4 and 5, respective tensioning members 1204 and 1224 are associated with the first flexible transmission member 1200 and with the second flexible transmission member 1220, contained, respectively, in the first compartment 1050 and in the second compartment 1052.

[0038] The first flexible transmission member 1200 and the second flexible transmission member 1220 comprise, respectively, a first chain 1206 and a second chain 1226; each of the remaining screening members 106'' carrying a second cogwheel 1068'' in an end position on the side of the second side 105'. The first screening member 106' carrying a first cogwheel 1068' for each respective end position in order to couple mechanically with the first chain 1206 on the side of the first side 105' and with said second chain 1226 on the side of the second side 105". However, it is opportune to specify that actuating the first belt transmission unit 120 and the second belt transmission unit 122 falls within the scope of the present invention, actuating said transmission units with belt transmission being functionally identical from a mechanical viewpoint. With particular reference to Figure 1, a first compartment 1050 is associated with the first side 105', containing the first transmission unit 120 and closed by a first cover 1054; on the other side of the screening device 1, a second compartment 1052 is associated with the second side 105', containing the second transmission unit 122, which is closed by a second cover 1056 (Figure 2).

[0039] With particular reference to Figures 4, 7, 8, the actuator 110 is of the hydraulic type and is provided with a drive shaft, known and not shown to save on drawing, mechanically connected to the first screening member 106' (Figure 4); a hydraulic circuit 200 is provided to drive the actuator 110 and to place the respective drive shaft in rotation in a clockwise direction. With particular reference to Figures 4 and 10, a lubrication unit 300 comprises a known grease tank not shown, which is connected to a grease distributor 302 carried by an inner wall of the first compartment 1050 / second compartment 1052 through a conduit 304 from which starts a feed conduit 306 for grease for each bearing corresponding with the first cogwheel 1068' (Figure 4 and Figure 10) and with the second cogwheels 1068" (Figure 10) in order to perform lubrication thereof automatically. To save on drawing, this feature is shown only in Figure 4 with reference to the first cogwheel 1068' contained in the first compartment 1050 and in Figure 10 with reference to the first cogwheel 1068' contained in the second compartment 1052, also applicable for all the second wheels 1068" of said compartment.

[0040] With particular reference to Figure 11, the hydraulic circuit 200 comprises, inside the compartment 101 not shown in Figure 11, a slide valve 114 connected hydraulically to the actuator 110 and switchable in the case of overpressure caused by any resistance to rotation encountered in use by the screening members 106' and 106''. In this regard, an overpressure sensor 116 is provided in combination with the actuator 110 or, interchangeably, with the slide valve 114 to command a relative automatic switching of the actuator 110, in order to reverse the rotation of the drive shaft of the actuator 110 and, therefore, the direction of rotation of the screening members 106' / 106'' in the case of one of them being prevented from rotating consistently. For this reason, in Figure 11 the reference number 116 of the overpressure sensor has been associated to the actuator 110 with a continuous line and to the slide valve 114 with a dashed-dotted line.

[0041] Use of the screening device 1 is easily understandable from what is described above and does not require further explanations. However, it could be useful to specify that the particular arrangement of the screening members 106' / 106" allows the material to be screened to be moved so as to prevent possible accumulation on the side of one of the two first plates 107 and on a second plate 108, in particular the plate positioned according to the direction of the motion component conferred on the material by the lobes 10620 of the moving members 1062. Furthermore, the particular orientation of the first plate 107 and of the second plate 108, parallel to each other and substantially aligned with the direction 10, facilitates sliding of the material to be screened, soil, sand, gravel or excavation waste, towards the second opening 104, optimising the step of discharge through the screening members 106' / 106". In particular, the resultants of the force of gravity and the force transmitted by the lobes 10620 positioned like the arrows (shown in Figure 9 tangential to the lines of the screening members 106' / 106'') on the material contained inside the box-shaped body 100 by each screening member 106' and 106'' rotating in an anticlockwise direction, project the material towards the plate 108, with which the last screening member 106" corresponds. This last screening member, together with the adjacent one, exert on the material received from the screening members 106 positioned on the side of the first screening member 106' a thrust with a vertical component upwards, with the consequence of projecting the material against the inner face of the second plate 108, and this also applies for the excavation waste contained inside the box-shaped body 100, which therefore, due to the reaction of the second plate 108 itself, falls above the granular material, facilitating the remixing and, in conclusion, the discharge thereof. Naturally, the opposite occurs in the case of clockwise rotation of all the screening members 106' and 106'', with the difference that the impact of the material contained inside the box-shaped body 100 occurs against the protective metal sheet 103 of the compartment 101, more clearly visible in Figure 7.

[0042] Due to the particular shape of the shafts 1060 of the screening members 106' and 106'' mentioned here above, the first cogwheels 1068' and the second cogwheels 1068" are couplable to the respective shaft 1060 prismatically, and such as to be interchangeable to vary, as desired, a transmission ratio with respect to the first screening member 106' / actuator 110. The function of the tensioning members 1204 and 1224 is clear in light of Figures 4 and 5 and it is opportune to specify that the choice of a single flexible member for each of the first transmission unit 120 and second transmission unit 122 allows the rotation speeds of each screening member 106" to be changed, as desired, simply by changing the number of teeth of the first cogwheel 1068' and second cogwheels 1068", therefore the transmission ratio with respect to the first screening member 106' / actuator 110 and to guarantee perfect operation of the first transmission unit 120 and second transmission unit 122 simply by adjusting, as desired, the pressure acting on the respective chain through the respective tensioning member 1204 / 1224. Furthermore, having provided the lubrication unit 300 with a feed conduit 302 for each first cogwheel 1068' and each second cogwheel 1068" allows performance of lubrication to be delegated to a known control unit, not shown, based on specific operating conditions, the number of hours of activity or at specific times of the day.

[0043] In conclusion, it is clear that changes and variants may be made to the screening device described and illustrated here without thus deviating from the scope of protection of the present invention.

[0044] With particular reference to the dimensions of each first cylinder C1, second cylinder C2 and third cylinder C3, and the relationships between them, it is clear that they could be different or coinciding, in relation to the design choices and field of use indicated in the design specifications. In any case, the presence of the hydraulic circuit 200 engages the volume V on the right-hand side in Figure 7, so it is permitted for the box-shaped body 100 not to be symmetrical with respect to a median plane M visible in Figure 8. Naturally, the shape of the box-shaped body 100 can be changed to position the screening members 106' and 106'' in a totally symmetrical manner with respect to the plane M, without thus limiting the scope of the present invention, provided that this solution is preferable with respect to the one discussed above to illustrate an embodiment of the present invention from an operating viewpoint, given that it will always be necessary to find a position for the hydraulic circuit 200 and that the position of the plate 107, as well as that of the relative adapter 1072, will always determine an operating conditioning for the screening device 1.

[0045] In the claims, any sign of reference between brackets should not be interpreted as a limitation of the claim. The term " comprising" does not exclude the presence of other elements or steps in addition to those listed in a claim. Furthermore, the term "one", as used in this context, is defined as one or more than one. Furthermore, the use of introductory expressions such as "at least one" and "one or more" in the claims should not be interpreted in the sense that introduction of another claim element identified using the indefinite articles "a" or "an" limits any particular claim in which said claim element appears singularly, even when the same claim comprises the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an". The same applies for the use of definite articles. Unless otherwise established, terms such as "first" and "second" are used to arbitrarily distinguish the elements that such terms describe. Consequently, these terms are not necessarily intended to indicate the temporal or other type of priority of these elements. The simple fact that several measurements are stated in reciprocally different claims does not indicate that a combination of these measurements cannot be used to advantage.

Claims

1. Screening device (1) comprising a tubular box-shaped body (100) extending in an established direction (10), having two opposing sides (105') (105") connected by an opposing first plate (103') and by an opposing second plate (108) that delimit a first opening (102) and a second opening (104) engaged fully by a plurality of screening members (106') (106"), each of which comprises a shaft (1060) carried from said sides (105') (105") in a freely rotating manner transversely to said direction (10) around a respective axis (1061); each said shaft (1060) carries a plurality of moving members (1062) arranged spaced between said first and second sides (105') (105") and provided with a plurality of lobes (10620) uniformly distributed peripherally; an actuator (110) being carried by said box-shaped body (100) between said sides (105) to carry in rotation said screening members (106') (106") so that, in use, each of said screening members (106') (106") envelops an ideal first cylinder (C1) of a first diameter determined through said lobes (10620); characterised in that the set of said first cylinders (C1) envelops an ideal second cylinder (C2) contained fully inside said box-shaped body (100); said second cylinder (C2) being positioned at a distance from said first plate (103') that measures a length lower than or equal to the diameter of said first cylinder (C1) and, with respect to said second plate (108), at a distance that measures a length comprised between one and one and a half times said first diameter.

2. The device according to claim 1, characterised in that said axes (1061) of said shafts (1060) envelop a surface shaped similarly to an ideal third cylinder (C3) of a diameter that approximates, rounded down, a distance between the first plate (103') and said second plate (108).

3. The device according to claim 1 or 2, characterised in that said first plate (103') and said second plate (108) are parallel to said direction (10), so as to delimit a prism-shaped screening volume (V) upstream of said screening members (106') (106").

4. The device according to any one of the preceding claims, characterised in that a first screening member (106') of said plurality of screening members (106') (106") is mechanically connected to said actuator (110) through a first transmission unit (120) carried by said box-shaped body (100) to a first side (105') of said two sides (105')(105") in order to be controlled in axial rotation; said first unit (120) having parallel axes and the remaining screening members (106") of said screening members (106'') being connected to said first screening member (106') through a second transmission unit (122) having parallel axes and being carried by said box-shaped body (100) to a second side (105'') of said two sides (105')(105").

5. The device according to claim 4, characterised in that said first transmission unit (120) comprises a first flexible transmission member (1200) (1206) mechanically coupled to said first screening member (106') and to said actuator (110) in respective end positions.

6. The device according to claim 4 or 5, characterised in that said second transmission unit (122) comprises a second flexible transmission member (1220) (1226) mechanically coupled to said first screening member (106') and to each of said remaining screening members (106") in respective end positions.

7. The device according to claim 6, characterised in that respective tensioning members (1204) (1224) are associated with said first flexible transmission member (1200) (1206) and said second flexible transmission member (1220) (1226).

8. The device according to any one of the preceding claims, characterised in that said moving members (1062) are arranged spaced between said first and second sides (105')(105") through the interposition of spacer rings (1064); end clamping means (1066) being provided in combination with said shaft (1060) for maintaining said moving members (1062) packed together with said rings (1064).

9. The device according to claim 8, characterised in that each said shaft (1060) is of the prismatic type and has a constant transverse section shaped like a regular polygon; each said moving member (1062) having a hub (1066) with a section being the negative copy of a transverse section of said shaft ((1060), in order to be axially mounted sliding with the respective said lobes (10620) facing or helical or angularly staggered, as desired.

10. The device according to any one of claims 6-9, characterised in that said first flexible transmission member (1206) and said second flexible transmission member (1226) comprise, respectively, a first chain (1206) and a second chain (1226); each of said remaining screening members (106'') carrying a second cogwheel (1068'') in an end position to said second side (105'); said first screening member (106') carrying a first cogwheel (1068') for each respective end position, in order to mechanically couple with said first chain (1206) on said first side (105') and with said second chain (1226) on said second side (105").

11. The device according to claim 10, characterised in that said second cogwheels (1068") are coupled to the respective said shaft (1060) so as to be interchangeable, in order to change, as desired, a transmission ratio with respect to said first screening member (106') / actuator (110) .

12. The device according to any one of claims 4-11, characterised in that said actuator (110) is of the hydraulic type and is mechanically connected to said first screening member (106'); a hydraulic circuit (200) being provided to power said actuator (110) and comprising a slide valve (114) hydraulically connected to said actuator (110) and switchable in the case of overpressure; an overpressure sensor (116) being provided to control a relative automatic switching of said actuator (110).

13. The device according to any one of claims 4-12, characterised in that a first compartment (1050) containing said first transmission unit (120) and closed by a first cover (1054) is associated with said first side (105'); a second compartment (1052) containing said second transmission unit (122) and closed by a second cover (1056) being associated with said second side (105').

14. The device according to any one of claims 10-13, characterised in that it comprises a lubrication unit (300) comprising a feed conduit (302) provided with a discharge opening (304) associated with each said first cogwheel (1068') and each said second cogwheel (1068'') in order to lubricate them automatically.

15. The device according to any one of the preceding claims, characterised in that said second plate (108) is delimited by a blade (1080) on the side of said first opening (102).

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