Abstract:
The present invention relates to a distribution star for containers of the type used in systems for manipulating containers (particularly bottles), for example in filling plants. 
     More particularly, the present invention relates to a distribution star of the type used in systems for manipulating containers, comprising a ring structure characterised in that it comprises:
       an annular fixed element that carries a plurality of grippers;   an annular displacing element that carries cam means for the grippers;   wherein the said annular displacing element is displaceable along a circumference of the said ring structure to set the said annular displacing element at different positions of the cam means with respect to the said grippers.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a distribution star for containers of the type used in systems for manipulating containers (particularly bottles), for example in filling machines. 
     BACKGROUND ART 
     Both linear and rotary filling machines are known to comprise a plurality of serially arranged operating units for the bottles to be moved therethrough. Plastic containers like PET bottles, particularly, are moved by being hooked at the neck by means of suitable grippers that are usually made of steel or resistant plastic. These grippers are controlled by suitable cams, which provide to close them around a bottle neck in the gripping stations, and then hold the same in this condition throughout the pathway to the release station. 
     However, in a filling machine, several bottle sizes can be usually processed. For each bottle size a different neck can be provided, so that the same gripper is not suitable for all the bottle types. In particular, the different diameters of the bottle necks in the various types needs that the jaws of the grippers be adapted for each diameter. This requires that the distribution star on which the grippers are mounted be disassembled and substituted with another star wherein the grippers suitable for the new diameter are mounted. This operation is lengthy and difficult, so that a relatively long stop of the plant is needed. 
     SUMMARY OF THE INVENTION 
     The problem at the heart of the present invention is thus to provide a distribution star for containers which does not require long and difficult operations for adapting it to different bottle necks diameters and avoids unacceptably long stop of the packaging process. 
     This problem is solved by a distribution star for systems for manipulating containers such as outlined in the annexed claims, whose wording is integral part of the present description. 
     Further features and advantages of the present invention will be better understood from the description of a preferred embodiment, which is given below by way of a non-limiting illustration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the inventive distribution star engaging the necks of bottles; 
         FIG. 2  is a top plan view of the star in  FIG. 1 ; 
         FIG. 3  is a bottom plan view of a particular of the star in  FIG. 1 ; 
         FIG. 4  is a sectional view according to the section IV-IV in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following specification, the terms “container” or “bottle” will be considered as synonymous. 
     With reference to the figures, the distribution star being the object of the present invention, which is generally designated with the numeral  1 , comprises a ring structure  2  that is mounted on a rotatable support  3 . The rotatable support  3  has a base  4  rotatably installed on a pedestal  5  and a plurality of legs  6  protruding upwards and diverging to connect with an annular plate  7 . The annular plate  7  carries distancing means  7   a  that are fixed to the ring structure  2  by means of fixing means  8  such as screws or others. 
     The ring structure  2  comprises four coaxial ring elements. 
     The most internal ring element is an annular support element  9  that is joined to the distancing means  7   a  by means of fixing means  8  such as screws or others as explained above. 
     A first median ring element is an annular displacing element  10  carrying the cam means  11  for the grippers  12 . 
     A second median ring element is an annular fixed element  13  that carries the grippers  12 . 
     The concentrically external ring element is an annular adjustable element  14  carrying notches  15  for receiving the bottle necks, as explained below. 
     A top annular joining plate  16  bridges the annular support element  9 , displacing element  10  and fixed element  13  and is removably fixed thereon by suitable fixing means  17 ,  17 ′ such as screws, even if other conventional fixing means may be suitable as well. When screws are used, the fixing means  17 ′ connecting the annular joining plate  16  with the annular displacing element  10  are preferably made of a screw-bolt assembly and pass through slots that are made in the annular displacing element  10 , in order to allow its displacement by rotation around the star axis once the screws have been loosened. 
     The annular displacing element  10  and the annular fixed element  13  comprise the gripper assembly, wherein the grippers  12  and the gripper mechanism are carried by the annular fixed element  13 , while the cam means  11  for actuating the grippers  12  are sustained by the annular displacing element  10 . 
     The grippers  12  comprise each first  18   a  and second  18   b  jaws. 
     Both the cam means  11  and the jaws  18   a ,  18   b  are pivotally hinged to the annular displacing element  10  and to the annular fixed element  13 , respectively, by means of suitable hinge means  19 ,  19 ′,  19 ″. The grippers  12  are positioned on the top side of the annular fixed element  13 , while the corresponding mechanism is set on the other side of this annular fixed element  13 . The cam means  11  are also set at the lower side of the corresponding annular displacing element  10  in order to interfere with the grippers mechanism, as will be described below. 
     The cam means  11  are of a conventional type, such as a disk cam  20  comprising a first reactive profile  20   a  intended to interact with the driven organ of the gripper and a second reactive profile  20   b  intended to interact with suitable guide means (not shown) arranged in a preset fixed position on the equipment, such as to control the opening and closure of the gripper  12  where desired. 
     The second jaw  18   b , hereinafter referred to as the guided jaw  18   b , is a rocker arm driven organ for the cam means  11 . The guided jaw  18   b  comprises a body  21  that is hinged to said annular fixed element  13  via the hinge means  19 ′ described above, a guide finger  22 , a shaft  23  joining the body  21  and the guide finger  22 , so that they move integrally, and a hook  24 . 
     The guide finger  22  is intended to interact with the cam means  11  and, in all the operating steps of the gripper  12 , it remains in contact with the first reactive profile  20   a  of the cam. 
     The hook  24  is intended to interact with the neck A of a container C, above the projecting collar B of the container C. 
     Spring means  25  are hinged to the guide finger  22 , on the portion proximate to the shaft  23 , by means of hinge means  26   a . At the opposite end, the spring means  25  are directly hinged to the annular displacing element  10  by hinge means  26   b . These spring means  25  are preloaded such that they tend to recall the guided jaw  18   b  in an open condition. The closure of the gripper  12  will thus take place against the resistance of the spring means  25  by the action of the cam means  11  on the guide finger  22 . 
     The guide finger  22  further comprises actuating means  27 , such as an actuating tooth, projecting in the direction substantially perpendicular to the axis of the guided jaw  18   b . Such actuating means  27 , in cooperation with the first jaw  18   a , are provided to open/close the gripper  12 . 
     The first jaw  18   a , which is pivotally hinged to the hinge means  19 , as said above, has a body  28  and a hook  29  that is entirely similar to the hook  24  of the guided jaw  18   b.    
     The first jaw  18   a  further comprises receiving means  30  for the actuating means  27  of the guided jaw  18   b . These receiving means  30  are joined to the body  28  of the first jaw  18   a  through a shaft (not visible) in order to rotate integrally. The receiving means  30  comprise a pair of teeth  31 ,  31 ′ which are separated by a gap that forms a seat for the actuating means  27  (actuating tooth) of the guided jaw  18   b.    
     The annular joining plate  16  have a plurality of slots  32  put in alignment with a through hole  32 ′ in the annular displacing element  10  and positioned in a substantially perpendicular relationship with respect to a radius of the distribution star  1 . 
     A pin  33  is inserted in the slots  32  and in the corresponding through hole  32 ′ and provides for the radial balancing of the annular displacing element  10  with respect to the support element  9  and the annular fixed element  13 . At least three slots  32  and pins  33  are necessary to allow a correct positioning of the annular displacing element  10 , but more than three can also be used, as shown in  FIG. 2 . 
     The annular adjustable element  14 , as said above, carries the notches  15 . The said notches  15  have an arcuate profile, the amplitude of which depends on the bottle size, i.e. larger bottle necks require a notch  15  of greater amplitude. Notches  15  of different amplitude are set in sequence along the perimeter of the said annular adjustable element  14  for the various bottle neck size normally used. 
     In transversal section (see  FIG. 4 ), the notches  15  show a slit profile  34  shaped to accommodate the projecting collar B of the bottle neck. This improves the engagement of the bottle by the grippers  12 . 
     Suitable loosening fixing means  35 , such as screw means, are provided to set the annular adjustable element  14  in a wanted positioned. As shown, the head  36  of the screw is sufficiently large to engage the lower side of the annular adjustable element  14 , which thus is pressed between the said head  36  and the lower side of the annular fixed element  13 . To allow centring of the annular adjustable element  14 , the annular fixed element  13  has a stepped profile  37  on which the said annular adjustable element  14  abuts. The stepped profile  37  acts as radial stopping means for the annular adjustable element  14 . 
     Once the loosening fixing means  35  are loosened, the annular adjustable element  14  can be disengaged and then rotated to position correctly the suitable notch  15  in alignment with the gripper  12 . 
     The operation of the inventive distribution star  1  will be now described. 
     Upon a non operating condition, the grippers  12  are in a rest condition, with the jaws  18   a ,  18   b  being opened. When the first reactive profile  20   a  of the cam means  11  acts on the guide finger  22 , the guided jaw  18   b  is driven to rotate clockwise against the resistance of the spring means  25 . The actuating means  27  will thus act against the walls of the teeth  31 ,  31 ′ of the second jaw  18   a , thus causing a counter-clockwise rotation of the same about the hinge means  19 . The rotation of the two jaws  18   a ,  18   b  causes the same to be closed around the neck of a container C, as shown in  FIG. 2  or  3 . 
     Upon the subsequent opening of the gripper  12 , i.e. when the first reactive profile  20   a  of the cam means  11  moves back to the rest position, the actuating means  27  will move again integrally with the guided jaw  18   b.    
     When a different diameter of neck bottle is to be managed in the distribution star  1 , the ring structure  2  can easily be adapted as described below. 
     The fixing means  17 ′ are loosened, in order to allow rotation of the annular displacing element  10  around the axis of the distribution star  1 . The rotation of the annular displacing element  10  can be facilitated by operating on the pins  33  and allowing them to move in the slots  32 . In such a way, the cam means  11  are displaced along a circumference of the distribution star. This causes the guide finger  22 , which is drawn by the preloaded spring means  25 , to also adapt against the first reactive profile  20   a  of the cam means  11  in a new rest position. As a consequence, the guided jaw  18   b  slightly rotates and, through the actuating means  27 , also causes the first jaw  18   a  to rotate at the same extent, so that both the jaws close or open to adapt to a different diameter of the neck of the bottle C. 
     Suitable adjustment marks, such as nicks or labels, can indicate, in connection with the different positions of the pins  33 , the diameter of the bottles to be treated, in order to facilitate the correct adjustment of the system. 
     The annular adjustable element  14  must also be adapted to the wanted diameter of bottle neck. This can be achieved by loosening the fixing means  35  (such as screw means) that set the annular adjustable element  14  in a fixed position and rotating it to allow the correct notches  15  to be positioned in alignment with the grippers  12 , as described above. Then the fixing means are again tightened to set the annular adjustable element  14  in the new operating condition. 
     The advantages of the distribution star  1  according to the invention are thus apparent. 
     Thanks to the described gripper mechanism, the displacement around the star axis of the cam means allow to adjust the amplitude of the jaws  18   a ,  18   b  of the grippers to different diameters of bottles necks. The notches  15  can also be easily adapted by rotation of the annular adjustable element  14 . 
     These adjustments can be made in an easy and fast way, without disassembling the distribution star  1 . This allows to strongly reduce the stop time of the plant and to increase productivity. 
     In a preferred embodiment, the actuating means  27  are as described in  FIG. 1  and pages 4-5 of European patent application no. 06425399.0 in the name of the same Applicant, whose corresponding disclosure is herein incorporated by reference. In summary, the actuating means  27  comprise a body that is not integral with the guided jaw  18   b  and that is, in turn, pivotally hinged to the hinge means  19 ′, from which the actuating means  27  projects in the direction substantially perpendicular to the axis of the guided jaw  18   b.    
     The body of the actuating means  27  is housed in a cavity having a substantially complementary shape which is purposely formed in the body of the guide finger  22 , proximally to the shaft  23 . Said body has a substantially circular plan section that is interrupted by a step forming a pawl, which abuts against an abutment surface of the body of the guide finger  22  and prevents the actuating means  27  from rotating clockwise, while counter-clockwise rotation is allowed. The body of the actuating means  27  further has a relief on which suitable spring means act upon. At the opposite end thereof, the said spring means act on a stop element being formed in the body of the guide finger  22  and are preloaded such as to hold the pawl pressed against the said abutment surface. 
     The actuating means  27  will integrally move with the guided jaw  18   b , due to the fact that the spring means acting on the actuating means  27  are suitably preloaded and thus counteract the thrust reaction to which the actuating means  27  are subjected and which would tend to cause them to rotate counter-clockwise. 
     Upon the subsequent opening of the gripper  12 , i.e. when the first reactive profile  20   a  of the cam means  11  moves back to the rest position, the actuating means  27  will move again integrally with the guided jaw  18   b  due to the pawl that prevents the actuating means  27  from rotating clockwise. 
     When an abnormal situation occurs, e.g. when a container C gets entangled in a fixed part of the machine, the neck of this container C acts as a lever on the first jaw  18   a , which thus rotates clockwise, thereby the teeth  31 ,  31 ′ act on the actuating means  27  such that it is forced to rotate counter-clockwise. As the actuating means  27  are free to rotate counter-clockwise against the resistance of the corresponding spring means, when the preload force of the said spring means is overcome, the gripper  12  opens as much as to allow the container C to be released without causing any damage to the gripper. On the contrary, when the actuating means  27  are integral with the guided jaw  18   b  as in the first embodiment described above, the gripper will be broken or at least damaged. 
     The fact that the gripper  12  is prevented from being damaged or broken by means of the inventive device not only means that the cost for spare parts has been decreased, but also and above all, that the number of interruptions of the plant operation for allowing the replacement of the damaged piece is dramatically reduced, which results in the optimization of the manufacturing cycle. 
     Thus, the combination of both the features of i) adjustment of the distribution star to different diameters of bottle necks and ii) imparting more elasticity to the gripper assembly to avoid accidental damage of the grippers  12 , as provided in the second embodiment described above, is particularly helpful to optimize the productivity of the plant, lessen the human intervention and thus reduce the operating costs. 
     It will be appreciated that only a particular embodiment of the present invention has been described herein, to which those skilled in the art will be able to make any and all modifications necessary for its adjustment to specific applications, without however departing from the scope of protection of the present invention as defined in the annexed claims.