Abstract:
A gripper for manipulating containers includes a support on which a cam mechanism is pivotally mounted. The gripper has a first jaw operated by the cam mechanism and a second jaw controlled by the first jaw. The first jaw has an actuator which interacts with a receiving mechanism on the second jaw for opening or closing the gripper. The actuator is pivotally associated with the first jaw so that, when force is applied by the receiving mechanism due to rotation of the second jaw relative to the first jaw, the actuator can rotate relative to the first jaw to allow the gripper to open.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a gripper for containers of the type used in systems for manipulating containers (particularly bottles), in filling plants. 
       BACKGROUND ART 
       [0002]    Both linear and rotary filling plants are known to comprise a plurality of serially arranged operating units for the bottles to be moved therethrough. Plastic (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. 
         [0003]    The bottles, however, sometimes happen to be entangled in parts of the machine. In this event, though becoming deformed, they do not break, and thus act as levers on the gripper that is locked by the cam in a closed condition, and cause serious damage to it. While steel grippers can be deformed, plastic grippers are easily broken, which implies that the latter have to be frequently replaced. 
       SUMMARY OF THE INVENTION 
       [0004]    The problem at the heart of the present invention is thus to provide a gripper for containers which does not get damaged even when a container is suddenly pulled apart. 
         [0005]    This problem is solved by a gripper for systems for manipulating containers such as outlined in the annexed claims. 
         [0006]    Further features and advantages of the gripper being the object 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 
         [0007]      FIG. 1  is a sectional plan view of the inventive gripper as being closed on a bottle; 
           [0008]      FIG. 2  is a plan view of the gripper in  FIG. 1  in the opened condition; 
           [0009]      FIG. 3  is a sectional plan view of the gripper in  FIG. 1  in a step of pulling apart the container; 
           [0010]      FIG. 4  is a view according to the section IV-IV in  FIG. 1 ; 
           [0011]      FIG. 5  is a view according to the section V-V in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    With reference to the figures, the gripper being the object of the present invention, which is generally designated with  1 , comprises a support  2  on which cam means  3  and first  4  and second  5  jaws of the gripper are mounted. 
         [0013]    As may be seen in  FIGS. 4 and 5 , the support  2  is plate-like and fixed to the moving system (not shown) of the containers  6 . Both the cam means  3  and the jaws  4 ,  5  are pivotally hinged to the support  2  by means of suitable hinge means  7 ,  7 ′,  7 ″, such as to hang from said support  2 . 
         [0014]    The cam means  3  are of a conventional type, such as a disk cam  8  comprising a first reactive profile  8   a  intended to interact with the driven organ of the gripper and a second reactive profile  8   b  intended to interact with suitable guide means arranged in a preset fixed position on the equipment, such as to control the opening and closure of the gripper  1  where desired. 
         [0015]    The first jaw  4 , hereinafter referred to as the guided jaw  4 , is a rocker arm driven organ for the cam means  3 . The driven jaw  4  comprises a body  9  that is hinged to said support  2  via the hinge means  7 ′ described above, a guide finger  10  and a hook  11 . 
         [0016]    The guide finger  10  is intended to interact with the cam means  3  and in all the operating steps of the gripper  1  it remains in contact with the first reactive profile  8   a  of the cam. 
         [0017]    The hook  11  is intended to interact with the neck of the container  6 , normally below the stop ring for the container closure, and comprises to the purpose a gripping profile  11   a  which is shaped such as to ensure, together with the matching hook of the second jaw  5 , the best grip on the neck of the container  6 . In substance, said gripping profile  11   a  is substantially semicircular and comprises a central depressed portion  12  and a peripheral portion  13  in relief, which are joined to each other in a stepped manner. 
         [0018]    Elastic means  14  are hinged to the body  9  of the guided jaw  4 , on the portion proximate to the guide finger  10 , by means of hinge means  9   a . At the opposite end, the elastic means  14  are directly hinged to the support  2  by means of hinge means  15 . These elastic means  14  are preloaded such that they tend to recall the guided jaw  4  in an open condition, such as shown in  FIG. 2 . The closure of the gripper  1  will thus take place against the resistance of the elastic means  14  by the action of the cam means  3  on the guide finger  10  of the guided jaw  4 . 
         [0019]    The body  9  of the guided jaw  4  further comprises actuating means  16  that, in cooperation with the second jaw  5 , provide to open/close the gripper  1 . These actuating means  16  comprise a body  17  that is, in turn, pivotally hinged to the hinge means  7 ′, from which an actuating tooth  18  projects in the direction substantially perpendicular to the axis of the guided jaw  4 . 
         [0020]    The body  17  of the actuating means  16  is housed in a cavity having a substantially complementary shape which is purposely formed in the body  9  of the guided jaw  4 . Said body  17  has a substantially circular plan section that is interrupted by a step forming a pawl  19 , which abuts against an abutment surface  19   a  of the body  9  and prevents the actuating means  16  from rotating clockwise, while counter-clockwise rotation is allowed. The body  17  further has a relief  20  on which the elastic means  21  act upon. At the opposite end thereof, the elastic means  21  act on a stop element  22  being formed in the body  9  of the guided jaw  4  and are preloaded such as to hold the pawl  19  pressed against the abutment surface  19   a.    
         [0021]    The second jaw  5 , which is pivotally hinged to the hinge means  7 ″, as said above, has a body  23  and a hook  111  that is entirely similar to the hook  11  of the guided jaw  4 , thereby the elements  112 ,  111   a  and  113  correspond to the elements  12 ,  11   a  and  13  of the guided jaw  4 . 
         [0022]    The second jaw  5  further comprises receiving means  116  for the actuating means  16  of the guided jaw  4 . Practically, from the body  23  of the second jaw  5  there projects a pair of teeth  24 ,  24 ′ which are separated by a concavity  25  that forms a seat for the actuating tooth  18  of the guided jaw  4 . 
         [0023]    The operation of the inventive gripper will be now described. 
         [0024]    Upon a non operating condition, the gripper  1  is as shown in  FIG. 2 , with the jaws  4 ,  5  being opened. When the first reactive profile  8   a  of the cam  8  acts on the guide finger  10 , the guided jaw  4  is driven to rotate clockwise against the resistance of the elastic means  14 . The actuating tooth  18  will thus act against the walls of the teeth  24 ,  24 ′ of the second jaw  5 , thus causing a counter-clockwise rotation of the same about the hinge means  7 ″. The rotation of the two jaws  4 ,  5  causes the same to be closed around the neck of a container  6 , as shown in  FIG. 1 . The actuating tooth  18  will integrally move with the guided jaw  4 , due to the fact that the elastic means  21  are suitably preloaded and thus counteract the thrust reaction to which the actuating means  16  are subjected and which would tend to cause them to rotate counter-clockwise. 
         [0025]    Upon the subsequent opening of the gripper  1 , i.e. when the first reactive profile  8   a  of the cam  8  moves back to the position in  FIG. 2 , the actuating tooth  18  will move again integrally with the guided jaw  4  due to the pawl  19  that prevents the actuating means  16  from rotating clockwise. 
         [0026]    When the anomalous situation occurs as shown in  FIG. 3  (e.g., when the container  6  gets entangled in a fixed part of the machine), the container  6  acts as a lever on the second jaw  5 , which thus rotates clockwise, thereby the teeth  24 ,  24 ′ act on the actuating tooth  18  such that it is forced to rotate counter-clockwise. As the actuating tooth  18  is integral with the actuating means  16  and these are free to rotate counter-clockwise against the resistance of the elastic means  21 , when the preload force of the elastic means is overcome, the gripper  1  opens as much as to allow the container  6  to be released without causing any damage to the gripper. On the contrary, when the actuating tooth  18  is integral with the guided jaw  5  as in the prior art grippers, the gripper will be broken or at least damaged. 
         [0027]    The advantages of the gripper  1  according to the invention are thus apparent. The fact that the gripper 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. 
         [0028]    It will be appreciated that only a particular embodiment of the gripper for container handling systems being the object 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.