Patent Publication Number: US-2020291604-A1

Title: Screening bucket

Description:
The present invention relates to a screening bucket. In particular, the present invention relates to a screening bucket that can be actuated by means of an articulated arm of an earthwork machine. In more detail, the present invention relates to a screening bucket that can be actuated by means of an articulated arm of an earthwork machine in order to separate elements of different sizes from heterogeneous excavated material. 
     BACKGROUND TO THE INVENTION 
     As known, screening buckets are excavating equipment that, coupled to the end of an excavating arm, allow to take heterogeneous material and to select it, separating the fine fractions from the rough fractions, and keeping these latter inside a basket provided with fixed or rotating grids. In case of rotating grids, the screening of the material is performed by means of a rotating cylindrical basket, usually driven into rotating by means of a hydraulic rotary actuator carried by the bucket frame at opposite side from the bucket blade, that is usually provided with teeth for crushing the surface of the area to be excavated. 
     It is easily understood that the size of the openings of the grid of the rotating basket determine the granulometry (size) of the material kept in the basket; moreover, it is clearly apparent that, in order to filter the excavated material to obtain fractions of different sizes, it is necessary to perform a screening in more steps (fractionated screening), and this is possible only by changing the basket after having loaded the material, that has been subjected to a first screening step, into a hopper, so that to change the grid and replace it with a rougher one, to load the residual material in the basket, and so on until to have only the material of greater size than the grid of maximum screening size. 
     It is clearly understood that this operation requires very long times, and therefore high operating costs. Alternatively, it is possible to have a plurality of buckets, each of which provided with a basket with holes of given dimension, different than the dimension of the holes of the other baskets. 
     It is clearly understood that none of these two solutions is satisfactory, as it is necessary to have available many baskets or buckets, which means very high costs for both the solutions. 
     In view of the situation described above, it would be desirable to have available a screening bucket that, in addition to allow limiting and possibly overcoming the drawbacks of the prior art, defines a new standard for this kind of equipment, both from the viewpoint of the product and of the method of use, and therefore of the method performed for fractionated screening without losing material during the operation of the screening basket and eliminating the shutdown times necessary to replace the current basket with a basket with different screening capability. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention relates to a screening bucket. In particular, the present invention relates to a screening bucket that can be actuated by means of an articulated arm of an earthwork machine. In more detail, the present invention relates to a screening bucket that can be actuated by means of an articulated arm of an earthwork machine in order to separate elements of different sizes from excavated material. 
     An object of the present invention is to provide a rotating screening basket for a screening bucket, allowing an adjustable screening of the heterogeneous material that has been excavated, in order to separate therefrom fractions of given size continuously definable at will. 
     According to the present invention a rotating screening basket for a screening bucket is provided, whose main features will be described in at least one of the appended claims. 
     A further object of the present invention is to provide a screening bucket provided with a rotating basket allowing to excavate heterogeneous material and to screening it in an adjustable manner, in order to separate therefrom fractions of given size continuously definable at will. 
     According to the present invention a screening bucket is provided, whose main features will be described in at least one of the appended claims. 
     A further object of the invention is to provide a method for continuous fractionated screening of incoherent excavated material by using a screening bucket. 
     According to the present invention a method is provided for screening incoherent excavated material by separating fractions of different size definable at will by using a screening bucket, wherein the main features of the method will be described in at least one of the appended claims. Moreover, in view of what above illustrated, a screening basket will be described below according to an embodiment, suitable for a screening bucket, the basket comprising a first cylindrical body having a central axis and a plurality of first holes, an actuating unit being provided for driving the first cylindrical body into rotation around the central axis; wherein the basket comprises a second cylindrical body housed inside the first cylindrical body; the second cylindrical body having a plurality of second holes, actuating means being associated with the first and second cylindrical bodies in order to move them with respect to each other so as to overlap the first and second holes. 
     An embodiment will be also described, wherein the first and second cylindrical bodies are so reciprocally associated, and the actuating means are so designed, that the rotation of one of the first and second cylindrical bodies through the actuating means results in a change in both the reciprocal position of the first and second cylindrical bodies along the longitudinal direction (parallel to the axis) and in their reciprocal position in rotational direction, wherein therefore, by means of the actuating means, one of the two cylindrical bodies is both translated and rotated with respect to the other body. 
     An embodiment will be also described, wherein the second cylindrical body, arranged inside the first cylindrical body, has a second diameter that is slightly smaller than a first diameter of the first cylindrical body and/or the first holes and the second holes have substantially the same width, so that, in use, when they perfectly overlap one another, the filtering capability exerted by the combination of the first and second cylindrical bodies is equal to the filtering capability of the first or second cylindrical body. 
     According to a further embodiment described herein, the basket comprises first centring means associated with the first cylindrical body in order to keep it coaxial with the central axis. 
     According to a further embodiment described herein, the second cylindrical body has a bottom closing it at the side of said centring means. 
     According to a further embodiment described herein, the centring means comprise a spoke-member coaxial with the central axis; the bottom portion being coupled to the spoke-member by means of a plurality of pins parallel to the central axis so as to be longitudinally movable with respect to the spoke-member. 
     According to a further embodiment described herein, the actuating unit comprises a first case supporting a second case in a freely rotatable manner; the first case and the second case being hydraulically coupled; the actuating unit and the actuating means are hydraulically coupled; the actuating means comprising a first linear actuator coaxial with the central axis to move the bottom axially with respect to the spoke-member. 
     According to a further embodiment described herein, each of the first and second holes is delimited by a first polygonal perimeter and by a second polygonal perimeter respectively, that are provided with first and second edges orthogonal to each other and having substantially constant width. 
     According to a further embodiment described herein, at least some first and second holes are square in shape and have substantially equal extension. 
     According to a further embodiment described herein, the case has, at the rear, hydraulic valves. 
     According to a further embodiment described herein, the actuating unit and the actuating means are hydraulically coupled; the actuating means comprising a second linear actuator arranged between the second cylindrical body and the first cylindrical body, so as to couple them together in a way that is axially fixed and can be angularly set at will within a given angular interval. 
     According to a further embodiment described herein, the second cylindrical body comprises a cylindrical element coupled to the second case in an axially and angularly rotatable way; the respective cylindrical element and second case having respective projections and recesses conjugated together so as to be, in use, reciprocally movable in a helical manner. 
     Below, a bucket will be described, provided with a basket according to any one of the embodiments illustrated, as well as a method for adjusting and/or setting a basket according to any one of the embodiments illustrated. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Further characteristics and advantages of the screening bucket, the screening basket and the method for fractionated screening according to the present invention will be more apparent from the description below, set forth with reference to the attached drawings, that illustrate some examples of embodiment, where identical or corresponding parts of the equipment are identified by the same reference numbers. In particular: 
         FIG. 1  is a front schematic perspective view of a first preferred embodiment of a screening bucket according to the present invention in a first operating configuration; 
         FIG. 2  is a back perspective view of the bucket of  FIG. 1 ; 
         FIG. 3  is a side elevational view of the bucket of  FIG. 1 , with some parts removed for the sake of clarity; 
         FIG. 4  is a perspective view from the bottom of the bucket of  FIG. 1 , with some parts removed for the sake of clarity; 
         FIG. 5  is a longitudinal cross-section of a front perspective view of  FIG. 1 , in reduced scale and with some parts removed for the sake of clarity; 
         FIG. 6  is a back view of a bucket extracted from  FIG. 1 , with some parts removed for the sake of clarity; 
         FIG. 7  is a longitudinal cross-section of  FIG. 6 ; 
         FIG. 8  is a perspective view from a rear viewpoint of a detail of  FIG. 6 , with some parts removed for the sake of clarity; 
         FIG. 9  is a longitudinal cross-section of  FIG. 8 ; 
         FIG. 10  is a perspective view from the bottom of  FIG. 1  in a preparatory configuration for removing the basket of  FIG. 6 , with some parts removed for the sake of clarity; 
         FIG. 11  is a schematic perspective view of a step of removing the basket of  FIG. 10 , with some parts removed for the sake of clarity; 
         FIG. 12  is a longitudinal view of a detail extracted from  FIG. 3  in a second operating configuration; 
         FIG. 13  illustrates  FIG. 12  in a third operating configuration; 
         FIG. 14  is a side elevational view of a detail extracted from  FIG. 3  in a first operating configuration; 
         FIG. 15  illustrates  FIG. 14  in a second operating configuration; 
         FIG. 16  illustrates  FIG. 14  in a third operating configuration; 
         FIG. 17  is a schematic side elevational view of a second preferred embodiment of  FIG. 1 ; 
         FIG. 18  is a schematic perspective view of  FIG. 17  from a rear viewpoint, comprising a detail in enlarged scale; 
         FIG. 19  is a schematic perspective view of a third preferred embodiment of  FIG. 1 ; 
         FIG. 20  is a schematic perspective view of a fourth preferred embodiment of  FIG. 1  comprising two details in enlarged scale. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     In  FIG. 1 , number  1  indicates, as a whole, a rotating screening basket  1  for a screening bucket  100 , validly usable for fractionated screening of excavated heterogeneous material, in order to separate therefrom fractions of given size that can be defined at will continuously. 
     The bucket  100  ( FIG. 11 ) is provided with a box-type frame  10  delimiting a space  20  that extends around a pivot axis  22  and is provided with respective support members  24  rotatable with respect to rotation axes parallel to the pivot axis  22 . With reference to  FIG. 2 , the frame  10  further comprises a rear portion  16  substantially shaped like an overturned “T”, a lower part  16 ′ of which is arranged transversally to the pivot axis  22 , extends downwards from the longitudinal portion  12  with two respective arms  162  and  162 ′ that are symmetrically inclined with respect to the longitudinal portion  12 . 
     With reference to  FIG. 1  again, and with particular reference to  FIGS. 2-4 , the frame  10  has a front portion  11  defining a round opening and is provided at the bottom with a blade  110 , to which teeth  111  are applied, projecting anteriorly; a longitudinal portion  12 , delimiting the space  20  at the top, extends at opposite side from the blade  110  and is provided at the top with a gripping member  14  usable to connect the bucket  100  to the end of an arm of an excavator known and therefore not shown. The frame  10  further comprises a pair of longitudinal members  17  and  17 ′, each of which extends from one of the arms  162  and  162 ′ up to the front portion  11  on the side of the blade  110 . The pair of longitudinal members  17  and  17 ′ is spaced transversally to the pivot axis  22  by a distance that is slightly greater than an outer diameter of the basket  1 , so as to delimit, together with the blade  110  and to the lower part  16 ′, an opening  170  through which the basket  1  can freely pass for being installed and removed. The back portion  16  has a housing  160  provided between the arms  162 ,  162 ′, and at least one roller  242  (or two rollers arranged symmetrically with respect to the pivot axis  22  on opposite sides), carried by the front portion  11  at opposite side with respect to the blade  110  facing the rear portion  16 . 
     The space  20  is so shaped as to house the basket  1  and a respective roto-translatory actuating unit  50 , for example of the fluid-dynamic type, better described below, coaxially with the axis  22 . In particular, the actuating unit  50  comprises an actuator  50 ′, for instance an hydraulic actuator of the type CPR-8 produced by Baltrotors, which has an interface rotatable around a given axis and is designed to control a hydraulic device, for instance a hydraulic actuator associated with the same interface. The actuating unit  50  is provided with a first cylindrical case  52  ( FIGS. 3-6 ) housing the actuator  50 ′ and coupled to the frame  10  in a fixed manner, in particular in the housing  160 , by means of a plurality of screws  53  (shown in  FIGS. 2, 14, 15 and 16 ), so as to keep the actuator  50 ′ with the central axis  51  coaxial with the pivot axis  22 , as it will be better described below. The actuating unit  50  supports, in turn, the basket  1  in a rigid and selectively releasable manner. In particular, the first case  52  anteriorly supports a hub-shaped cylindrical portion  420  freely rotatable around the axis  51 ; this hub-shaped portion  420  supports, in turn, a second cylindrical case  54  in an axially slidable manner. Obviously, due to the features of the actuator type CPR-8 with which the actuator  50 ′ is constructed, this latter can be hydraulically supplied through a power circuit by means of in- and out-openings  55 , only two of which are visible in  FIGS. 14-16 . 
     With particular reference to  FIG. 1  and to the enlargement on the side, the basket  1  comprises a first cylindrical body  30  made of metal sheet or of any other functionally equivalent material. With reference to  FIG. 1  again, the basket  1  comprises a second cylindrical body  60 , at least partially housed in the first cylindrical body  30  and coaxially coupled to the first cylindrical body  30  in a longitudinally free and angularly fixed manner through a plurality of centring pins  622 . 
     The first cylindrical body  30  is coaxial with the central axis  51  and is rigidly coupled to the spoke-member  42  extending radially from the hub-shaped portion  420 . The cylindrical body  30  is therefore pivoted to the frame  10  through the centring unit  40  provided with the spoke-member  42  and with the hub-shaped portion  420 , coaxially with the central axis  51 . The centring unit  40  is so designed as to be kept coaxial with the pivot axis  22  cooperating with each roller  242  having a respective peripheral portion  2420  externally adjacent to the same first cylindrical body  30 . Therefore, each roller  242  is arranged at a radial distance from the pivot axis  22  that is quiet equal to an outer radius of the first cylindrical body  30 . Therefore, the spoke-member  42  of the centring unit  40  keeps the first cylindrical body  30  and the second cylindrical body  60  coaxial with the axis  22 / 51 . 
     The cylindrical body  30  has a plurality of first holes  32  (square-shaped in the embodiment illustrated, but they may have different shape), better shown in  FIG. 3 , for example moulded and arranged according to rectilinear directrixes wound on the cylindrical mantel  33  of the first cylindrical body  30  similarly to the generatrixes of lined surfaces, according to a base angle of 45° with respect to the central axis  51  and distributed at a given angular pitch. Thanks to the fact of geometrically distributing the holes  32  as described above, the holes  32  are arranged longitudinally at a first given pitch P 1  and longitudinal rows of holes  32 , that longitudinally overlap one another, are substantially displaced with respect to one another by a length that is slightly greater than a half diagonal of a hole  32 . 
     Similarly to the first cylindrical body, the second cylindrical body  60 , provided with a bottom  624 , reinforced anteriorly by means of a plurality of ribs  621 , has a plurality of second holes  62  arranged, like the first holes  32 , on the first cylindrical body  30 , and therefore longitudinally at a second given pitch P 2 . Therefore, the first and second holes  32 / 62  are respectively delimited by a first square perimeter  320  and by a second square perimeter  620 , provided with first and second edges  320 ′ and  620 ′ that are orthogonal to each other and have constant width. 
     The second cylindrical body  60  is arranged inside the first cylindrical body  30  and has a second diameter D 2  that is slightly smaller than a first diameter D 1  of the first cylindrical body  32 ; the first holes  32  and the second holes  62  have substantially the same width, so that, in use, when they overlap each other, the filtering capability resulting by combining the first and second cylindrical bodies  30 / 60  is equal to the filtering capability of the single first or second cylindrical body  30 / 60 , so as to act together as the basket  1  would comprise only one of them (one of the two cylindrical bodies  30  and  60 ). 
     Each of the first and second holes  32 / 62  is delimited by a first square perimeter  320  and by a second square perimeter  620 , polygonal and delimited by first and second edges that are orthogonal to each other and have constant width. 
     In view of the above description, the integral coupling between the second cylindrical case  54  and the hub-shaped portion  420  of the spoke-member  42  allows driving the first cylindrical body  30  (and therefore the second cylindrical body  60 ) into rotation with respect to the frame  10 . Again with reference to  FIG. 5 , the second cylindrical case  54  extends beyond the hub-shaped portion  420  crossing the spoke-member  42  and contains a fluid-dynamic linear actuator  56  supplied by the actuator  50 ′ through a pipe  50 ″, shown only in  FIG. 5 . The actuator  56  is carried coaxial with the central axis  51  and is arranged between the spoke-member  42  and the bottom  624 . In particular, the linear actuator  56  has a stem  57  rigidly connected to a head  58  of the second cylindrical body  60  delimiting anteriorly the case  54 , and is rigidly and coaxially coupled to a bottom  624 . In view of the above description, the head  58  together with the second cylindrical case  54 , with the second cylindrical body  60  and with the spoke-member  42 , is longitudinally movable with respect to the frame  10  and is able to rotate together with the first cylindrical body  30 . it should be noted that, with reference to  FIG. 8 , the bottom  624  carries, at the rear, centring pins  622  parallel to the central axis  51  and engaging a plurality of holes  422  ( FIG. 6 ) provided radially at given angular pitch in a ring  423  of the spoke-member  42 . In view of the above description, the second cylindrical body  60  is angularly fixed with respect to the first cylindrical body  30  around the central axis  51  through the spoke-member  42 . 
     The bottom  624  of the second cylindrical body  60  has the function of protecting the actuating unit  50  against the material contained in the basket  1  and each roller  242  is coupled to the front portion  11  in a releasable manner, so that the basket  1  can freely access the space  20  from the bottom through the opening  170  for mounting/removing operations. 
     The operation of the basket  1  and of the bucket  100  is clearly apparent from the description above and does not require further explanations. However, it is useful to specify that, with references to  FIGS. 4 and 11-16 , where the basket is illustrated with the respective first and second cylindrical bodies  30  and  60  arranged in different relative positions, and, in particular, with the respective first and second edges  320 ′ and  620 ′ completely overlapping each other ( FIG. 4 ) and therefore with the holes  32  and  62  completely free to allow the passage of elements of maximum size, the basket  1  is in maximum screening configuration; with the respective first and second edges  320 ′ and  620 ′ partially overlapping each other, and therefore with the holes  32  partially closed by the edges  620 ′ of the second cylindrical body  60 , the basket  1  is in intermediate screening configuration ( FIG. 12 ); with the respective first and second edges  320 ′ and  620 ′ partially overlapping each other, and therefore with the holes  32  closed in a cross-like manner by the edges  620 ′ of the second cylindrical body  60  ( FIG. 13 ), the basket  1  is in minimum screening configuration.  FIGS. 14, 15 and 16  illustrate the linear actuator  56  with the head  58  thereof keeping the bottom  624  in the various positions corresponding to the configurations of the basket  1  described above, in maximum, intermediate and minimum screening configuration. 
     Lastly, it is clearly apparent that variants and modifications can be done to the basket  1  and the screening bucket  100  comprising it, described and illustrated herein, without however departing from the protective scope of the invention. 
     For example, it should be specify that the holes  32  and  62  of the first and second cylindrical bodies  30  and  60  may have the same shape, as well as different shape according to the operating needs. Usually, without however limiting the protective scope of the invention, these holes may have round, triangular, pentagonal shape. 
     Moreover, the relative motion between the first and second cylindrical bodies  30  and  60  for adjusting the overlapping degree of the respective first and second holes, and therefore the screening degree of the basket  1  resulting from the different overlapping degree of the holes  32  and  62 , may be also different than an axial movement, as it is shown in  FIGS. 17 and 18 , where the two components always have axial-symmetrical shape concentric to the axis  51  but at least the second cylindrical body  60  has a truncated-conical end portion  61  contained inside the spoke-member  42 ′, modified so as to have respective inclined arms  43  facing the truncated-conical portion  61 . In this case, the second cylindrical body  62  has a hub  623  that can be keyed on the first case  52  and the first cylindrical body  30  is coupled through a hub  420 ′ of its spoke-member  42 ′ to the hub  623  in an axially fixed an angularly rotatable manner. Moreover, the hub  623  and the spoke-member  42 ′ are coupled together on the respective cylindrical peripheries by means of a linear actuator  6230  arranged between brackets  6231  and  6232  extending radially from the hub  623  and from the spoke-member  42 ′ respectively. This allows to make the first and the second cylindrical bodies  30  and  60  coupled in an axially fixed and angularly adjustable manner within a given angular interval. The actuator  6230  may be of the fluid-dynamic type as in  FIG. 18 , without however limiting the scope of the present invention, and has hydraulic coupling holes  6233  for being actuated. It is easily understood that in this case the second cylindrical body  60  drives the first cylindrical body  32  through the actuator  6230 . 
     The truncated-conical portion may be replaced with a flat portion, provided with holes of any shape. 
     With particular reference to  FIG. 19 , a third embodiment of the basket  1  is illustrated, wherein the screening capability of the basket  1 , i.e. the overlapping degree of the first and second holes  32  and  62 , is controlled through the linear actuator  56 , but the first cylindrical body  30  and the second cylindrical body  60  are replaced with a first prismatic body  30 ′ and a second prismatic body  60 ′ respectively. These two bodies are geometrically similar in order to be coupled so as to be able, like the first and the second cylindrical bodies  30  and  60 , to longitudinally slide with respect to each other, but they are so shaped as to obtain V-shaped portions, indicated with  70  and  71  respectively, that arranged at given angular pitch along the cylindrical extension of both the bodies. Therefore, in this embodiment each first and second body  30 / 60  can be geometrically reproduced by projecting, along the axis  51 , a polygonal shape having round segments  72  and  73 , concentric with the axis  51 , alternated with V-shaped portions  70  and  71  arranged radially. The holes  32 ′ and  62 ′ provided in the first prismatic body  30 ′ and in the second prismatic body  60 ′ are equal to the first holes  32  and to the second holes  62 , and are therefore delimited by rectangular perimeters. In this case it is easy to understand that the basket  1  of  FIG. 19  is associated with an auxiliary mechanical constraint given from the plurality of V-shaped portions  72  and  73  of the relative angular position of the respective components that, in use, have a screening function, in addition to that given by the linear actuator  56 , having the function of reducing the torsional stresses of the linear actuator  56  instead of, or in addition to, the centring pins  622 . 
     With reference to  FIG. 20 , a further embodiment of the basket  1  is illustrated, wherein the first cylindrical body  30  and the second cylindrical body  60  are substantially the same in shape and dimension as those of  FIGS. 1-16 , but the type of relative movement is different, as it is not only linear/axial or rotatory, but roto-translatory. In order to achieve this, the first cylindrical body  30  and the second cylindrical body  60  respectively have the hub-shaped portion  420  and the second case  54  provided with respective projections  302  and recesses  602  conjugated to one another so as to be, in use, reciprocally movable in a helical manner. Obviously, the head  58  is coupled to the stem  57  of the linear actuator  56  in an axially fixed and freely rotatable manner, so that to the relative axial movement between the first cylindrical body  30  and the second cylindrical body  60  controlled by the stem  57  a rotary motion corresponds, whose combination produces a relative helical motion of the first and second cylindrical bodies  30  and  60 . In any case, it should be specified that a screening bucket constructed like the bucket  100 , provided with the basket  1  produced according to any one of the embodiments described and illustrated above, represents a significant progress with respect to the prior art, thanks to which it is possible to overcome the drawbacks of the prior art, as it allows fractionated screening of the excavated material without losing material during operation and eliminating the shutdown times necessary to replace the screening basket with a basket of different screening size, thus allowing high production savings.