Abstract:
Containers are conveyed through a carousel type filling machine by a plurality of grippers each comprising a bracket element, and a pair of jaws connected to the bracket element by way of relative pivots; the two jaws are joined one to another by a removable segment of elastic material positioned with two ends seated in corresponding sockets afforded by the jaws. During the steps in which the containers are taken up and subsequently released by the grippers, the two jaws rotate about the two pivots and are centered by a locating pin, the pivots, the pin and the bracket element all being molded in a single piece from plastic material.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a conveying unit for containers in filling machines. 
     The invention finds application to advantage in machines for filling containers both with liquid substances and with powder substances. 
     Such conveying units consist substantially of a main carousel rotatable about a vertical axis and supporting a supply tank containing the substances; the carousel receives a succession of containers each presenting a body and filler mouth, which are taken up at a first transfer station from a first rotary infeed conveyor. 
     The supply tank is equipped at the bottom with a plurality of filler valves, each of which can be associated with the mouth of a respective container in such a manner that when the carousel is set in motion, the tank rotates about the vertical axis and its contents are dispensed by way of the filler valves into the containers, whereupon the filled containers are directed by way of a second transfer station onto a second outfeed conveyor. 
     During the filling operation, more particularly, the containers revolve as one with the valves about the axis of rotation of the tank and are maintained in the correct filling position, that is to say, the filler mouth substantially in coaxial alignment with the relative valve, by a plurality of support and restraint assemblies. Each of these assemblies is equipped with two grippers, lower and upper, of which the relative jaws are positioned respectively to restrain the body and the neck of the individual container. More exactly, each gripper comprises a bracket element connected to a given point on the periphery of the main carousel, also a pair of jaws occupying a common plane and connected thus to the bracket element by way of relative pivots. The two jaws are interconnected by a spring of which the opposite ends are anchored to respective fixed pins rigidly associated with the jaws. The spring serves to maintain the two jaws in the gripping position, in which they combine to afford a seat proportioned to accommodate and restrain a part of the container body or the container neck, respectively. The edge profiles presented by the free ends of the jaws and by the contours of the seat are shaped according to the type and geometry of the container that is to be gripped: an expedient that serves, initially, to facilitate the take-up of the empty container into the seat during its transfer from the first infeed conveyor to the support and restraint assembly, and thereafter, to facilitate the release of the filled container during the course of its transfer from the support and restraint assembly to the second outfeed conveyor. Both the take-up movement and the release movement of the container are generated in a substantially radial direction, relative to the main carousel, overcoming the elastic force of the aforementioned spring, of which the tension will be appropriately calculated on a case by case basis. 
     Accordingly, it will be evident that the two jaws must remain permanently free to rotate about their respective pivots and that the spring likewise must maintain a correct tension over time, so that the take-up and release movements will always employ the same degree of force, otherwise the smooth operation of the machine could be jeopardized. 
     It is common practice with carousel type filling machines to obtain the long-term dependability in question by using pivots fashioned from special metallic materials and given a surface treatment such as will ensure durability from the structural standpoint, superior resistance to wear, and low friction, and likewise using a coil spring made of special material to ensure that its tension remains constant over time. 
     It has been found in practice, nonetheless, that the metal pivots of the gripper jaws tend to stray from their correct structural position and assume positions unable to guarantee smooth operation of the gripper over time; moreover, given the nature of the products being dispensed and the fact that these inevitably will come into contact with the metal components mentioned above, both the pivots and the coil springs of the grippers are attacked by the substances in question with the result that their operation is adversely affected. This means frequent servicing and/or frequent replacement of the affected parts, and correspondingly high costs. 
     The object of the present invention is to provide a unit for conveying containers, such as will be unaffected by the above drawbacks. 
     SUMMARY OF THE INVENTION 
     The stated object is realized according to the invention in a conveying unit for containers in filling machines, machines wherein the containers are held firm by a plurality of grippers each comprising a bracket element, a pair of jaws connected to the relative bracket element by way of corresponding pivots, and to advantage, at least one segment of elastic material connected separably by one end to at least one of the two gripper jaws through the agency of respective anchor means, said anchor means comprising: at least two knuckles fashioned integrally with the segment of elastic material, one at each end, at least two sockets afforded one by each gripper jaw serving to accommodate a respective knuckle end. 
    
    
     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 shows a portion of a filling machine by which liquid and/or powder materials are dispensed into containers, illustrated schematically and in perspective; 
     FIG. 2 shows the portion of the filling machine as in FIG. 1, illustrated in a plan view. 
     FIGS. 3 and 4 show a detail of FIG. 1, in plan and in an exploded view, respectively, illustrated in a first embodiment; 
     FIGS. 5 and 6 show the detail of FIG. 3 viewed in plan and illustrated in two further embodiments. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIGS. 1 and 2 of the drawings attached,  1  denotes a portion, in its entirety, of a filling machine by which substances  2  of liquid or powder consistency are dispensed into single containers  3  each presenting a filler mouth  4 . 
     The filling machine  1  comprises a main carousel  5  rotatable about a vertical axis  6 , moving clockwise as viewed in FIGS. 1 and 2 and tangentially to a first transfer station  7  through which containers  3  are supplied to the main carousel singly and in succession by a rotary infeed conveyor  8 . 
     The infeed conveyor  8  rotates counterclockwise as seen in FIGS. 1 and 2 about a vertical axis  9  parallel to the main axis  6 , tangentially to a first infeed station  10  at which it receives a succession of containers  3  proceeding along a first predetermined path P 1  afforded by a horizontally disposed infeed channel  11 ; the channel is equipped with a screw feeder  12  and a relative motor  13  by which the containers  3  are advanced intermittently toward the infeed station  10  along the first feed path P 1  in a direction denoted F 1 . 
     The carousel  5  is disposed and embodied in such a way as to support the containers  3  and serves also to carry a tank  14 , rigidly associated with the carousel and furnished with a plurality of filler valves  15  equispaced about the vertical axis  6  of rotation. The filler valves  15  are designed in such a way that each will assume a position of alignment above the mouth  4  of a relative container  3  as the tank  14  rotates about the axis  6 , propelled by the carousel  5 , allowing a quantity of the substance  2  contained in the tank to be dispensed into each of the single containers  3 ; the advancing containers  3  are caused at the same time to follow a second predetermined feed path P 2  extending around the axis  6  of rotation, along which the filling step will take place, and once filled are released onto a rotary outfeed conveyor  16  by way of a second transfer station  17 . 
     The outfeed conveyor  16  rotates counterclockwise as seen in FIG. 1 about an axis  18  parallel to the axis  6  of the carousel  5 , and serves to direct the filled containers  3  from the second transfer station  17  through an outfeed station  19 , thence into an outfeed channel  20  aligned with the infeed channel  11 , along which they advance in a direction denoted F 2  following a third predetermined path P 3  toward a pickup unit not indicated in the drawings. 
     The infeed conveyor  8  comprises a shaft  21  placed concentrically with the respective axis  9 , carrying a platform  22  at the bottom, and at least one disc element  23  uppermost that consists in a star wheel of conventional embodiment, presenting an ordered succession of peripheral recesses  24  each partially accommodating a relative container  3  standing on the platform  22 . The conveyor  8  also comprises an external fence  25  combining with the periphery of the star wheel  23  to define a respective channel  26  along which the containers  3  pass from the infeed station  10  to the first transfer station  7 . 
     In similar fashion to the infeed conveyor  8 , the outfeed conveyor  16  comprises a shaft  27  disposed concentrically with the relative axis  18 , carrying a platform  28  at the bottom and at least one star wheel element  29  uppermost presenting an ordered succession of peripheral recesses  30  each partially accommodating a relative container  3  standing on the platform  28 . The conveyor  16  also comprises an external fence  31  combining with the periphery of the star wheel  29  to define a respective channel  32  along which the containers  3  pass from the second transfer station  17  to the outfeed station  19 . 
     The aforementioned channels  26  and  32  are merged respectively with the infeed and outfeed ends of a filling channel  33  located beneath the tank  14  and extending along the second predetermined path P 2 , compassed on the one hand by the carousel  5  and on the other by a fence  34  concentric with the axis  6  of rotation. 
     As illustrated in FIGS. 1 and 2, the carousel  5  comprises a plurality of assemblies  35  associated one with each filler valve  15 , by which a single container  3  is supported and restrained in such a way as to remain correctly positioned during the filling operation, that is to say with the mouth  4  substantially in coaxial alignment with the filler valve  15 . Each assembly  35  comprises a platform at the bottom (not shown in the drawings) on which to stand the single container  3 , and two grippers both denoted  36 , lower and upper, serving respectively to retain the body  3   a  and the neck  4   a  of a single container  3  between their relative jaws  37 . 
     Referring to FIGS. 3 and 4, each gripper  36  incorporates a bracket element  38  connected to a vertical post  39  (FIGS. 1,  2  and  3 ) forming part of a relative support and restraint assembly  35  and disposed parallel to the axis  6  of the carousel  5 , also a pair of jaws  37  occupying a common plane and connected each by one first end  40  to the bracket element  38  by way of a respective pivot  41 . More exactly, each first end  40  presents a hole  42  open on one side as to allow quick assembly with the relative pivot  41 , which in turn presents a head  43  of enlarged diameter affording a stop that ensures the jaw  37  cannot work free once assembled. 
     Each one of the two jaws  37  presents a socket  44  accessible from the periphery by way of a relative notch  45 ; the sockets  44  and the notches  45  of each gripper  36  combine when the relative jaws  37  occupy the closed position (indicated by solid lines in FIG. 3) to create a slot  46  such as will accept a segment  47  of elastic material presenting a central web  48  and two knuckle ends  49 . The two ends  49  are proportioned to locate in the relative sockets  44  with a degree of interference, whilst the web  48  occupies the two notches  45 . 
     More exactly, the two knuckle ends  49  and the respective sockets  44  constitute means  50  by which the segment  47  of elastic material is anchored to the jaws  37  as the jaws are drawn by the selfsame segment into the closed position (indicated by the solid lines in FIG.  3 ), in which they combine to afford an arcuate seat  51  partially accommodating and gripping the body  3   a  or neck  4   a  of the single container  3 . The bracket element  8  also comprises a locating pin  52  positioned between the pivots  41  and the slot  46 , which is interposed between the jaws  37  in such a way as to register with matching recesses  53  fashioned in the selfsame jaws  37  and thus ensure that these are disposed symmetrically when in the closed position. 
     In particular, the segment  47  of elastic material is obtained by extruding a continuous section and then cutting transversely through the section; the operation of fitting the segment into the slot  46  is accomplished with notable ease, as likewise is its removal from the slot. Both the pivots  41  and the pin  52  are embodied integrally with the bracket element  38  which can be fashioned, for example, in molded plastic. 
     More precisely, the gripper shown in FIGS. 3 and  4  is designed in particular to accommodate the neck  4   a  of a single container  3  in the seat  51  afforded by the relative jaws  37 , whereas the two grippers  36  of FIGS. 5 and 6 are designed each to accommodate the body  3   a  of a single container  3  in the seat  51  afforded by the relative jaws  37 . The gripper of FIG. 5 differs from that of FIG. 3 only inasmuch as the bracket element  38  presents two locating pins  52 , each designed to register with a respective recess  53  afforded by the jaw  37 , whilst the gripper of FIG. 6 differs from those of the other drawings in that it comprises not only two locating pins  52  but also two segments  47  of elastic material. In this particular instance, each such segment  47  is disposed with one knuckle end  49  occupying the relative socket  44  of one jaw  37  and the other end  49  occupying a respective socket  54  afforded by a connecting plate  55  secured to the bracket element  38  with two anchor pins  56 . 
     To advantage, the profiles of the free ends  57  presented by the two jaws  37 , denoted  58 , and the profiles of the edges presented by the seat  51 , denoted  59 , will be shaped according to the type and geometry of the container  3  and according to the part of the container  3  they are required to grip, namely the body  3   a  or the neck  4   a , thereby facilitating the take-up and subsequent release of the container by the grippers  36 . 
     In operation, referring to FIGS. 1 and 2, the container is taken up into the seats  51  afforded by the grippers  36  at the first transfer station  7  as the container  3  passes from the first conveyor  8  to the relative support and restraint assembly  35  of the carousel  5 . During the course of this transfer, the container  3  is subjected to a pushing action in a substantially radial direction, relative to the carousel  5 , with the result that it bears against the aforementioned end profiles  58  and forces the jaws  37  to open. The jaws  37  thus rotate about the two pivots  41  to the point of assuming the spread position indicated by phantom lines in FIGS. 3,  5  and  6 , overcoming the resistance of the segment  47  of elastic material which consequently extends, allowing the container  3  to locate in the seat  51 , then retracts so that the container is restrained in the selfsame seat  51 . 
     On reaching the end of the feed path P 2  followed along the filling channel  33 , the container  3  will be released from the seat  51  of the gripper  36  at the second transfer station  17  and pass from the support and restraint assembly  35  of the carousel  5  to the outfeed conveyor  16 . During the course of this transfer, the container  3  is subjected to a pushing action in a substantially radial direction relative to the assembly  35 , equal and opposite to that of the infeed movement, with the result that it will bear against the edge profiles  59  of the seat  51  and force the gripper jaws  37  to open. The jaws  37  thus rotate about the two pivots  41  to the point of assuming the spread position indicated by phantom lines in FIGS. 3,  5  and  6 , overcoming the resistance of the segment  47  of elastic material which consequently extends, so that the container  3  is able to abandon the seat  51 . 
     It will be clear that the notion of embodying the bracket element  38  integrally with the pivots  41  and pins  52  is instrumental in reducing the number of components and improving the mechanical strength of the selfsame pivots, besides cutting production costs. It will be seen also that lubrication is no longer necessary, and that the segment of elastic material can be replaced at decidedly minimal cost, compared to the coil springs and anchor pins of prior art solutions. Moreover, the plastic material utilized to make both the bracket element and the segment of elastic material has been found to be affected neither by the substances being batched, nor by the substances containing detergents and disinfectants used typically to clean the conveying unit. This further advantage also guarantees longer life of the conveying unit, which requires less maintenance and is characterized by lower operating costs.