Patent Publication Number: US-6666237-B2

Title: Dispensing device in machines for filling containers with powder material

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a dispensing device for powder material. 
     In particular, the present invention finds application advantageously in the art field of automatic filling machines equipped with a carousel carrying a plurality of filler heads from which powder material is dispensed into containers. 
     Each of the aforementioned filler heads comprises a dispensing device designed to direct a given quantity of material by free fall into a relative container positioned on a platform assembly. The platform assembly is equipped with a load cell, located beneath the assembly and connected to the dispensing device, which serves to sense the weight of the container during the fill. Once the load cell senses a predetermined value corresponding to the final filled condition of the container, it will pilot the dispensing device to cut off the flow of powder material. 
     More exactly, the dispensing device receives the powder material from a vessel by way of a feed duct connected to a bottom end of the selfsame vessel, in such a way that the material can be released by gravity and in measured quantities. In addition, the dispensing device comprises an element located to coincide with an outlet at the bottom end of the duct, by means of which the duct can be closed off selectively. 
     A first such closure element embraced by the prior art presents a valve consisting in a lever mounted pivotably to a fixed supporting frame. The lever exhibits a substantially circular portion positionable under the outlet in such a way as to close it off completely. 
     The valve is operated through the agency of a relative linear actuator that shifts the lever by causing it to rotate about the pivot axis. Thus, the circular portion is directed along a path transverse to the longitudinal axis of the duct and into a position under the outlet in such a way as to occlude the selfsame outlet and cut off the flow of powder material. 
     In reality, the filling method outlined above betrays a drawback connected with the operation of closing the outlet. As the circular portion moves across, in effect, the powder material in flight is diverted and consequently does not drop correctly into the container. 
     This drawback is attributable to the nature of the movement described by the circular portion, which drags a part of the powder material along the direction of this same movement (transverse to the direction of the flight), diverting it and causing it to spill outside the container. The part of the material not directed into the container thus drops onto the platform assembly, creating problems in the sense that the machine must be cleaned and a proportion of the powder material remains unused. 
     The prior art also embraces devices that comprise a feed duct extending through an annular chamber. The duct remains fluid-tight with respect to the annular chamber, which is associated with extractor means and caused to draw in air through an annular port coaxial with the outlet of the duct. 
     Thus, the part of the powder material diverted by the valve is intercepted and aspirated through the port into the annular chamber. 
     The aspirated material is then returned to the vessel for subsequent reuse. 
     Even with this second prior art solution however, there is a significant drawback attributable to the constructional complexity of the extraction system. In effect, carousel filling machines are generally equipped with a not inconsiderable number of filler heads. Consequently, if an extraction system of the type previously outlined is to be associated with each of the dispensing devices, this represents an excessive increase in production costs per single filling machine. 
     A further drawback derives from the fact that the extraction system can be rendered ineffective when the machine is employed to dispense certain powder materials of which the particles are notably heavy. In this instance the particles remain unaffected by the aspirating action, which is not sufficient to counteract the gravitational force that causes the particles diverted away from the container mouth to continue falling. 
     The object of the present invention is to provide a dispensing device for powder filling machines operating with containers, which will betray none of the aforementioned drawbacks. 
     In particular, it is an object of the invention to provide a dispensing device for powder filling machines operating with containers, such as will cut off the flow of powder material without any part of the material being scattered outside the container. 
     SUMMARY OF THE INVENTION 
     The stated object is realized according to the present invention in a dispensing device applicable to machines for filling containers with powder material, comprising a feed duct referable to a longitudinal axis and furnished with at least one outlet from which the powder material is dispensed into a corresponding container; also closure means associated with the outlet, capable of movement between an operating condition in which the outlet is closed to disallow the passage of the powder material, and a non-operating condition in which the outlet remains open 
     Closure means according to the invention comprise a plurality of occluding elements each capable of movement between a first position corresponding to the operating condition of the closure means, and at least a second position corresponding to the non-operating condition of the closure means. The single occluding element obscures a part of the dispensing outlet when in the first position, and combines with the remaining elements when in the second position to establish a flow section affording a passage to the powder material. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: 
     FIG. 1 illustrates a first preferred embodiment of a dispensing device in accordance with the present invention, applicable to machines for filling containers with powder material, viewed schematically in a side elevation and with certain parts omitted for clarity; 
     FIG. 2 illustrates the device of FIG. 1 in a first operating condition, viewed in plan with certain parts omitted for clarity; 
     FIG. 3 illustrates the device of FIG. 2 in a second operating condition; 
     FIG. 4 illustrates a second embodiment of the dispensing device according to the invention, viewed in plan with certain parts omitted for clarity and in a first operating condition; 
     FIG. 5 illustrates the device of FIG. 4 in a second operating condition; 
     FIGS. 6 to  9  illustrate a third and a fourth embodiment of the dispensing device according to the invention, viewed in plan with certain parts omitted for clarity and shown respectively in the two operating conditions. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIG. 1 of the accompanying drawings,  1  denotes a dispensing device, in its entirety, for machines used to fill containers  2  with powder material. In particular, the filling machines in question are of the type mentioned in the foregoing prior art statement. 
     The device  1  comprises a duct  3  of substantially tubular embodiment, terminating in a first end  3   a  furnished with an outlet  4  from which the powder material is dispensed. At the end opposite from the first end  3   a,  the duct  3  is connected to a vessel (not illustrated in the drawings) containing the aforementioned powder material. 
     The dispensing outlet  4  is positioned above a relative container  2 , illustrated schematically in FIG.  1  and presenting a mouth  2   a  directed toward the outlet  4 . More exactly, the outlet  4  presents the shape substantially of a ring with an internal peripheral surface  6  affording a channel  7  such as will accommodate sliding movement. The channel  7  consists advantageously in a groove extending the full developable length of the internal peripheral surface  6 . 
     The dispensing device  1  further comprises closure means  5  associated with the outlet  4 , such as can alternate between an operating condition in which the outlet  4  is closed to disallow the passage of the powder material, and a non-operating condition in which the outlet  4  remains open to allow the passage of the selfsame material. 
     Such closure means  5 , which in FIG. 1 of the drawings are shown in the non-operating condition, consist in a plurality of occluding elements  8  occupying the outlet  4 , each with a peripheral portion  9  inserted slidably in the channel  7 . 
     More exactly, and with reference to FIG. 2, the internal peripheral surface  6  of the outlet  4  is of substantially polygonal, and preferably hexagonal geometry. 
     Each occluding element  8  appears substantially as a plate, presenting a trapezoidal and preferably isosceles geometry when viewed in plan. Thus, the peripheral portion  9  of each element  8  is defined by one of the oblique sides of the trapezium, whilst the oblique side opposite and the greater base constitute respective first and second peripheral sliding surfaces  10   a  and  10   b.    
     There are six occluding elements  8  in the example of FIG. 2, each disposed with the oblique side constituting the peripheral portion  9  offered to a relative side of the hexagonal internal peripheral surface  6  of the outlet  4 . 
     In this configuration, the peripheral sliding surfaces  10   a  and  10   b  of the occluding elements  8  are offered in sliding contact one to another. More exactly, each occluding element  8  is disposed with the first peripheral sliding surface  10   a,  that is to say the oblique side remote from that coinciding with the peripheral portion  9 , butted against the second peripheral sliding surface  10   b  or greater trapezoidal base of the relative adjacent occluding element  8 . 
     Thus, the occluding elements  8  are translatable one relative to the next along their respective peripheral sliding surfaces  10   a  and  10   b,  and along the peripheral portions  9 , between a first position corresponding to the closed operating condition of the closure means  5 , and at least a second position that corresponds to the non-operating condition of the closure means  5 . In the first position, each occluding element  8  obscures a part of the outlet  4  so that as an assembly the elements  8  will combine to occlude the outlet  4  completely. 
     Also forming part of the dispensing device  1  are drive means  11  associated with at least one of the occluding elements  8 , by which the elements  8  can be translated steplessly between the first and the second position, as will be seen in due course, through a series of intermediate positions. 
     The drive means  11  consist in an actuator  13  comprising a rod  12  anchored at one end to one of the occluding elements  8  and caused to reciprocate along a direction, denoted A, coinciding with its own longitudinal axis and extending parallel to the peripheral portion  9  of the occluding element  8  with which the drive means  11  are associated. 
     In the second position, the occluding elements  8  establish a flow section  14  aligned concentrically with the longitudinal axis  15  of the duct  3 , as illustrated in FIG. 3, and affording a passage to the powder material. 
     The flow section  14  is compassed by a portion of the second peripheral sliding surface  10   b  of each occluding element  8  directed toward the center of the outlet  4 . During the movement between the first and the second position, the occluding elements  8  will define a succession of concentric intermediate sections smaller than that of the flow section  14  established when the elements  8  occupy the second position. 
     As discernible in FIGS. 2 and 3, one occluding element  8 , disposed with a first peripheral sliding surface  10   a  engaging the second peripheral sliding surface  10   b  of the occluding element  8  associated with the drive means  11 , presents an opening that serves to accommodate the actuator rod  12 . 
     With reference to FIG. 4, which illustrates a second embodiment of the dispensing device  1 , the occluding elements  8  each present a substantially elongated appearance. 
     Each occluding element  8  presents a substantially wedge-like portion  17  at one end, terminating in a vertex  17   a  that coincides with the longitudinal axis  15  of the duct  3  when the occluding element  8  occupies the first position. 
     The wedge-like portion  17  is defined by a convex edge  17   b  and a concave edge  17   c  converging on the vertex  17   a.    
     The end of the occluding element  8  opposite from the wedge-like portion  17  incorporates a hinge  18  embodied as a through hole afforded by the selfsame element  8 , freely accommodating a first pivot  19  disposed parallel to the longitudinal axis  15  of the duct  3 . The occluding elements  8  are connected at points coinciding with these same hinges  18  to a plurality of rod-like link elements  20 . Thus, each link element  20  is associated with two occluding elements  8 . 
     More exactly, each link element  20  presents a first end  20   a,  and a second end  20   b  remote from the first end, both of which affording a through hole. Each first pivot  19  engages the hole in the first end  20   a  of one link element  20  and the hole in the second end  20   b  of a adjacent link element  20 , with the result that all the occluding elements  8  are connected mechanically one with another 
     Each occluding element  8  is associated with the dispensing outlet  4  by way of a fulcrum pivot  21 , anchored permanently to the peripheral part of the selfsame outlet and occupying a hole  21   a  located between the wedge-like portion  17  and the hinge  18  of the occluding element  8 . 
     The fulcrum pivot  21  extends longitudinally in a direction parallel to the longitudinal axis  15  of the duct  3 . Accordingly, the occluding elements  8  are rotatable, each about the respective fulcrum pivot  21 , between the first and second positions. The second embodiment in question likewise has six occluding elements  8  arranged peripherally around the outlet  4 , in this instance occupying different planes lying transverse to the longitudinal axis  15  of the duct  3 . In the first position, the occluding elements  8  are disposed with the respective wedge-like portions  17  converging radially on the center of the outlet  4 . In this configuration, the concave and the convex edges  17   b  and  17   c  of the wedge-like portions  17  overlap one another. 
     In this second embodiment, the rod  12  of the drive means  11  can be associated to advantage with one of the link elements  20 , or directly with the hinge  18  of a relative occluding element  8 . 
     Referring to FIG. 5, the occluding elements  8  are disposed, when in the second position, with the wedge-like portions  17  tangential to the outlet  4 . In this configuration, the concave edges  17   c  of the single occluding elements  8  are disposed in such a manner as to establish a flow section  14  appearing substantially circular in shape. 
     FIGS. 6,  7 ,  8  and  9  of the drawings illustrate two embodiments of the device differing from one another in terms of the particular shape exhibited by the singe occluding element  8 . 
     More exactly, FIG. 6 illustrates an occluding element  8  of substantially triangular outline, again presenting a wedge-like portion  17  of which the vertex  17   a  coincides with a first vertex  22  of the triangular figure. 
     As in the previous embodiment, the wedge-like portion  17  presents a convex edge  17   b  and a concave edge  17   c.  Each two adjacent occluding elements  8  occupy different planes lying transverse to the longitudinal axis  15  of the duct  3 , so that the concave and convex edges  17   b  and  17   c  overlap one another. 
     In this embodiment of the device, each occluding element  8  affords a slot  23  positioned at a second vertex  24  and accommodating a second pivot  25 . This pivot  25  is associated with a third vertex  26  of each occluding element  8 , which consequently is coupled to the slot  23  of the adjacent element  8 . 
     With a fulcrum pivot  21  positioned between the second and third vertices  24  and  26 , the occluding element  8  is able to rotate between the first and second position. Likewise in this embodiment, the fulcrum pivot  21  is anchored permanently to the peripheral part of the outlet  4 . 
     In the second position of the device, illustrated in FIG. 7, the occluding elements  8  are disposed in the same manner as those of the embodiment shown in FIG. 5, with the concave edges  17   c  combining to establish a circular flow section  14  and the wedge-like portions  17  tangential to the outlet  8 . During the movement between the first and second positions, the pivot  25  associated with the third vertex  26  of each occluding element  8  is caused to slide along the respective slot  23 . Again in this embodiment, the rod  12  is coupled advantageously to at least one of the occluding elements  8 . 
     With reference to FIG. 8, which illustrates a further embodiment of the dispensing device  1 , the occluding elements  8  are substantially triangular in embodiment as described above in referring to the embodiment of FIG.  6 . 
     Again, there is a wedge-like portion  17  with a concave edge  17   c  and a convex edge  17   b,  the latter in this instance presenting a recess  27  at a given point along its length. 
     Referring to FIG. 9, the recess  27  is disposed in such a way that when the occluding elements  8  occupy the second position, the portion of each element  8  overlapping the adjacent element  8  will not interfere with the fulcrum pivot  21  of the selfsame adjacent occluding element. 
     In operation, referring to the first embodiment of the device illustrated in FIGS. 1,  2  and  3 , the rod  12  is set in motion by the actuator  13 , which can be embodied advantageously as an electro magnet. 
     The rod  12  displaces the occluding element  8  with which it is associated, in the direction denoted A, causing the relative peripheral portion  9  to slide within the channel  7  along a path that corresponds to one side of the hexagonal internal peripheral surface  6 . As a result, the occluding element  8  in question passes from the first position illustrated in FIG. 2 to the second position illustrated in FIG.  3 . 
     The occluding element  8  driven directly by the rod  12  also pushes against the adjacent element  8 , causing the relative peripheral portion  9  to slide within the channel  7  along a path that corresponds to the side of the hexagonal internal peripheral surface  6  with which this same adjacent element  8  is associated. 
     More precisely, the first peripheral sliding surface  10   a  of the occluding element  8  actuated directly by the rod  12  pushes against the second peripheral sliding surface  10   b  of the adjacent occluding element  8  with which it is in contact. In this way, the occluding element  8  subjected to the pushing force will slide between the channel  7  and the peripheral surface  10   a  of the driving element, moving in a direction substantially transverse to the longitudinal axis  15  of the duct  3 . 
     The movement generated in this way is transmitted similarly to all of the occluding elements  8 , which will translate one relative to the next with the respective peripheral surfaces  10   a  and  10   b  sliding one against another, moving along the channel  7  to assume the second position illustrated in FIG.  3 . 
     In this way, the elements combine to create a flow section  14  disposed concentrically with the longitudinal axis  15  of the duct and affording a passage to the powder material. 
     A predetermined quantity of powder material is allowed to flow into the container, and when this is sensed by a load cell (not illustrated in the drawings) associated with the filling machine, the drive means  11  will return the occluding elements  8  to the first position, reducing the flow section  14  and closing the passage. 
     As the occluding elements  8  move from the second position back to the first position, a portion of each element  8  is caused to occupy an increasingly larger part of the flow section  14 , the effect of which being to define a succession of progressively smaller and concentric intermediate sections  14 . These intermediate sections  14  continue to reduce gradually in width until the occluding elements  8  return to the first position, corresponding to the operating condition of the closure means  5 , in which passage of the powder material is disallowed. 
     Advantageously, the flow of powder material in flight toward the container  2  is cut off without undergoing any change in direction (which coincides with the longitudinal axis  15  of the duct  3 ). 
     The advantage in question is attributable to the movement of the occluding elements  8 , which, in the process of returning from the second to the first position, combine one with another to ensure the powder material passes consistently through a flow section centered on the longitudinal axis  15  of the duct  3 . Accordingly, there is no displacement of the powder material in any direction transverse to the longitudinal axis  15  such as could result in a diversion away from the container  2 , as occurs with devices embodied according to the prior art 
     In the second embodiment of FIGS. 4 and 5, the occluding elements  8  are connected one to another by the link elements  20  and caused thus to rotate about the fulcrum pivots  21 . In like manner to the first embodiment, the occluding element  8  driven directly by the actuator rod  12  is set in motion, and its movement transmitted mechanically to the other elements  8 . 
     In particular, the occluding element  8  driven directly by the rod  12  rotates on its pivot  21  and the relative hinge  18  is caused thus to shift in a direction transverse to the longitudinal axis  15  of the duct  3 . The hinge  18  in turn displaces the link element  20  with which it is associated, and thereby displaces all the link elements  20  and hinges  18  associated with the other occluding elements  8 . 
     Accordingly, all the occluding elements  8  rotate in the same direction, with the result that the respective wedge-like portions  17  are distanced from the center of the outlet  4  and moved from the first position (illustrated in FIG. 4) to the second position (illustrated in FIG.  5 ). 
     When occupying the second position, the occluding elements  8  combine to establish the flow section  14  presented to the powder material. In this position the concave edges  17   c  of the single elements  8  are arranged in a circular formation and with no break in continuity, describing the circumference of the section  14 . 
     Once the predetermined amount of powder material has been dispensed, the occluding element  8  driven directly by the rod  12  is set in motion, causing the rest of the occluding elements  8  to rotate in the direction opposite to the previous direction and return thus from the second position to the first position. During the course of this movement, with the wedge-like portions  17  encroaching on the flow section  14 , the vertices  17   a  converge on the center of the outlet  4  to the point at which they become radially disposed relative to the selfsame outlet  4 . 
     As in the case of the first embodiment described, the wedge-like portions  17  occupy an increasingly larger part of the flow section  14  during their movement from the second position to the first position, defining a succession of intermediate flow sections  14 . These intermediate sections  14  continue to reduce gradually in width, remaining concentric, with the result that the advantages mentioned in describing the operation of the first embodiment are the same in the case of this second embodiment. 
     With regard to the operation of the third and fourth embodiments illustrated in FIGS. 6 to  9 , the occluding element  8  associated directly with the drive means  11  is caused to rotate about the relative fulcrum pivot  21  in the manner described previously when referring to the operation of the second embodiment. 
     During its movement from the first position (FIG. 6) to the second position (FIG.  7 ), the occluding element  8  in question rotates in such a manner that the second vertex  24  is distanced from the center of the outlet  4  and the third vertex  26  consequently moved toward the outlet  4 . This causes the pivot  25  of the adjacent occluding element  8  to be pulled by the corresponding slot  23  and drawn in sliding contact toward the outlet  4 . The movement induced in the occluding element  8  driven directly by the rod  12  thus occasions the rotation of all the other occluding elements  8  linked mechanically one with another. 
     When occupying the second position, the occluding elements  8  are disposed, similarly to those of the second embodiment described, with the respective vertices  17   a  tangential to the longitudinal axis  15  of the duct  3  and the concave edges  17   c  combining to define the circumference of the flow section  14 . 
     In the case of the fourth embodiment illustrated in FIGS. 8 and 9, the operation is substantially the same as that of the third embodiment. 
     Whilst the overlapping contact between adjacent occluding elements  8  is more pronounced in this instance, there is no interference between the one occluding element  8  and the fulcrum pivot  21  of the overlapped element  8 . 
     This feature is obtained as result of furnishing each occluding element  8  with the recess  27 , which locates freely against the fulcrum pivot  21  of the adjacent occluding element  8  when occupying the second position. Thus, notwithstanding the fulcrum pivot  21  is rigidly associated with the outlet  4 , extending parallel to the longitudinal axis  15  of the duct  3 , it remains unaffected by the movement of the overlapping element  8 . 
     As any person skilled in the art will appreciate, all of the alternative embodiments illustrated have the advantage of presenting a flow section to the powder material that remains aligned concentrically with the longitudinal axis  15  of the feed duct  3 . Accordingly, the powder material is not diverted along directions transverse to the longitudinal axis  15  but drops correctly into the container  2 .