Abstract:
Containers are transferred from a first conveyor operating at a first height to a second conveyor operating at a second height by a rotary unit equipped with a plurality of grippers designed to take up and support each successive container by the neck. The grippers are carried by respective slides mounted to corresponding vertical guide elements making up the main frame of the unit, on which they are made to move up and down cyclically by a first roller following a first track that extends around a fixed C-shaped tubular element, and by a second roller running on a second track presented by the top surface of a sector rail placed with the concave side directed toward the lateral opening in the C-shaped tubular element. The tubular element is easily replaced in the event of a size changeover.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a transfer unit for containers. 
   More exactly, the present invention is applicable advantageously to machines for filling and capping containers generally considered, and in particular, bottles taken up from a first conveyor coinciding for example with the outfeed of a filler or capper, and transferred to a second conveyor on which they advance toward a downstream machine, for instance a labeler. 
   In prior art systems, bottles leaving the first conveyor will be restrained generally by the neck, whilst the second conveyor operates at a height dictated by the downstream machine and presents an entry portion adjustable for height in such a way as to accommodate variations in the longitudinal dimension of different bottles. 
   This means in practice that the entry portion of the second conveyor is inclined in the manner of a chute, and in certain cases the resulting angle may be unacceptably steep, so that the bottles cannot be conveyed properly or remain balanced. 
   The object of the present invention is to provide a transfer unit that will overcome the drawback in question by ensuring bottles are directed correctly and safely onto the second conveyor. 
   SUMMARY OF THE INVENTION 
   The stated object is realized in a transfer unit for containers according to the present invention. 
   The unit disclosed comprises means by which to grip and hold single containers take up from a first conveyor operating at a first height, and feed means by which the gripping means are advanced along a predetermined transfer path extending between the first conveyor and a second conveyor operating at a second height. 
   Also forming part of the unit are means by which to bring about a controlled variation in the height of the gripping means during their passage along the predetermined transfer path. 

   
     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 bottling line for containers, comprising a transfer unit according to the present invention, illustrated in a schematic plan view 
       FIG. 2  shows the unit of  FIG. 1  in a schematic elevation view, with parts illustrated in section; 
       FIG. 3  is an enlarged detail of  FIG. 2 ; 
       FIG. 4  shows a detail of  FIG. 2 , illustrated in perspective; 
       FIG. 5  is an enlarged detail of  FIG. 1 , from which certain parts are omitted; 
       FIGS. 6 and 7  are plan views showing a detail of  FIG. 1  in two different operating configurations. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to  FIG. 1  of the accompanying drawings,  1  denotes a portion of a bottling line for filling containers  2 , each presenting a body  3  and a neck  4  (FIGS.  2  and  3 ). 
   The line  1  comprises a transfer unit  5  rotatable about a vertical axis  6 , turning counterclockwise as seen in  FIG. 1 , through a receiving station  7  at which the selfsame unit takes up a succession of containers  2  from a first rotary conveyor  8  turning clockwise about at axis (not illustrated) disposed parallel to the main axis  6 . 
   The function of the unit  5  is to transfer the containers  2  to a release station  9  coinciding with a second linear conveyor  10  advancing substantially tangential to the unit  5  in a direction denoted F 1 , by which the containers  2  are carried toward a further station (not illustrated) of the bottling line  1 . 
   The transfer unit  5  comprises a vertical shaft  11  extending upward from a bed  12  concentrically with the main axis  6 . The shaft  11  carries a flange  13  at the free top end, also a disc element  14  mounted to the flange and furnished around the periphery with a plurality of angularly equispaced pairs  15  of vertical guide elements  16  aligned on respective axes parallel to the main axis  6 , of which the free ends are directed toward the bed  12 . The flange  13 , the disc  14  and the guide elements  16  combine to establish a moving frame  17  and together constitute feed means  18  by which the containers  2  are carried along a path  19  consisting in a closed loop and including a transfer path  19   a  that extends from the receiving station  7  to the release station  9 . 
   Associated with each pair  15  of guide elements  16  are vertically slidable means  20  that comprise a slide  21  carrying means  22  by which to hold and support a single container  2 . More exactly, the top face  23  of the slide  21  presents a pair of vertical pivots  24  ( FIGS. 1 and 5 ) serving to support and enable the angular movement of a pair of jaws  25  and  26  functioning as means  27  by which to grip the neck  3  of a single container  2 . 
   As discernible in  FIGS. 2 and 3 , the transfer unit  5  further comprises means  28  by which to vary the height of the jaws in such a way as will render them capable of movement, more exactly, between a first higher level at which the containers  2  are taken up at the receiving station  7 , and a second lower level at which the containers  2  are deposited at the releasing station  9 . 
   The aforementioned height variation means  28  include means  29  by which to guide the movement of the slides  21 , consisting in a tubular element  30  that presents a C-shaped cross-sectional profile and a longitudinal opening  30   a  and is centered on the vertical shaft  11 . The bottom part of this same tubular element  30  is furnished with respective quick coupling and fastening means  31  operating in conjunction with fastening means  32  afforded by a sleeve  33  secured to the bed  12  coaxially with the shaft  11 , which comprise a circular plate  34  and a ring  35  with radial lugs  36  positioned above the plate (FIGS.  6  and  7 ). 
   The guide means  29  also comprise a sector  37 , coinciding with an arc to a circle centered on the shaft  11 , which is positioned with the concave side directed toward the opening  30   a  and mounted rigidly to the bed  12  in a manner not illustrated. 
   More exactly, the aforementioned guide means  29  comprise respective cam profile means  38  composed of a first track  39  extending around the outer cylindrical surface  40  of the tubular element  30 , and a second track  41  afforded by the top surface of the circular sector  37 . The two tracks  39  and  41  are substantially complementary one to another, and present a combined length enabling them to extend around the full 360° compass of the looped path  19  aforementioned, including the transfer path  19   a  along which the holding and supporting means  22  are caused to advance. 
   As discernible in  FIGS. 2 and 3 , each slide  21  comprises relative engagement means  43  interacting with the first and second tracks  39  and  41 . 
   More precisely, the engagement means  43  comprise a first roller  44  mounted freely to the end of a radial pivot  45  projecting from the slide  21  toward the cylindrical surface  40  of the C-shaped tubular element  30 , and a second roller  36  mounted freely to a pivot  47  disposed parallel to the pivot  45  first mentioned and carried by an arm  48  extending downward from the slide  21 . The first roller  44  is insertable into the first track  39 , whilst the second roller  46  runs on the second track  41 . 
   In operation, containers  2  are taken up singly and in succession from the first conveyor  8  at the receiving station  7  by the holding and supporting means  22 , positioned at the aforementioned first height. During the course of the passage onto the transfer unit  5 , the container  2  is subjected to a radial pushing force that has the effect of opening the jaws  25  and  26  and causing the neck to locate in a seat  49  afforded by the rounded ends of the selfsame jaws  25  and  26 , against the resilient action of a spring  50 . 
   In the course of the take-up step, during which the holding and supporting means  22  are positioned at a height substantially level with the neck  4  of a container  2  standing on the first conveyor  8 , the slide  21  is supported by the second roller  46  as it runs on the surface  42  of the sector  37 , advancing along the transfer path  19   a  to the point at which the first roller  44  engages with the first track  39  of the tubular element  30 . 
   With the transfer unit  5  then continuing to turn about the center axis  6 , the height of the slide  21  will change as the first roller  44  advances along the profile of the corresponding track  39 . 
   As illustrated in  FIG. 4 , the cam profile of the first track  39  presents a first substantially straight portion  39   a  engaged by the first roller  44  with the second roller  46  still advancing along the relative track  41 , followed by a first descending inclined portion  39   b  engaged by the first roller  44  after the second roller  46  has separated from the surface  42  of the sector  37 , and next in sequence, a substantially horizontal portion  39   c  along which the holding and supporting means  22  are positioned at a height substantially level with the neck  4  of a container  2  standing on the second conveyor  10 . 
   The transfer unit  1  further comprises actuating means  51  by which to produce the opening movement of the holding and supporting means  22 , consisting in a cam sector  52  fixed to the outer cylindrical surface  40  of the tubular element  30  and designed to interact with a following roller  53  carried by the end of an arm  54  associated with one jaw  26 . 
   The profile of the cam sector  52  is such as to engage the following roller  53  and cause the jaw  26  in question to rotate about the relative pivot  24 . The jaw  26  in turn presents a tooth profile  55  by which the other jaw  25  is caused to rotate about the relative pivot  24  in the opposite direction. 
   Following the step by which the container  2  is released to the second conveyor  10 , the holding and supporting means  22  continue to advance along the circular path  19 , the following roller  53  separates from the cam sector  52  and the jaws  25  and  26  are drawn together by the spring  50 . 
   Passing beyond the horizontal portion  39   c  of the track  39 , the first roller  44  passes onto a second ascending inclined portion  39   d  and the slide  21  is caused to return upwards along the respective guide elements  16 , bringing the holding and supporting means  22  up to a height level with the neck  4  of a container  2  advancing on the first conveyor  8 . 
   During this same step, the first roller  44  passes along a third and final straight portion  39   e  of the first track  39 , whilst the second roller  46  regains the sector  37  and begins to advance along the first part of the top surface  42 . 
   Importantly, the transfer unit  5  according to the present invention presents the advantage of being readily adaptable to any size of container  2 , since it allows a rapid replacement of the cylindrical tubular element  30  and sector  37 . After an initial twisting movement serving to release it from the fastening means  32  rigidly associated with the shaft  11 , the tubular element  30  can be removed with ease, thanks in particular to the C-shaped geometry described and illustrated, by inducing a sideways movement transverse to the axis  6  of the shaft  11 . 
   Accordingly, to fit a new tubular element  30  with a first track  39  of different profile, the element is first translated radially into a position of coaxial alignment with the shaft  11 . Thereafter, the tubular element  30  is shifted axially in such a manner that the internally projecting lugs  56  of a C-shaped sector  57  presented by the bottom of the tubular element  30  are caused to locate between the radial lugs  36  mentioned previously and register against the plate  34 , thereby assuming the position illustrated in FIG.  6 . 
   Finally, a twisting movement left or right will cause the lugs  56  to lodge between the plate  34  and the ring  35 , thereby locking the tubular element  30  to the shaft  11  as illustrated in  FIGS. 2 and 7 . Any risk of the element twisting loose accidentally will be prevented by retaining means, illustrated as spring-loaded plungers  58  disallowing relative movement between the plate  34  and the lugs  56 .