Abstract:
A container handling system for applying closures to containers includes a container feed line and a capping station for receiving containers from the container feed line and applying closures thereto. The capping station includes a capping head configured to provide torque during closure application. A container holder is configured to resist container rotation. The holder includes an opening exposed to a container location and a device positioned to draw air from the container location through the opening to create a force the acts to pull the container toward the opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 60/987,814, filed Nov. 14, 2007, the details of which are incorporated by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present application relates generally to systems for applying closures to containers, and more particularly to a system that uses suction to resist container rotation during application of a closure to the container. 
       BACKGROUND 
       [0003]    The manufacture of containers is in many cases complicated by the necessary application of a closure to the container. The closure must be properly and securely attached so that the container is completely closed, but in mass production, this process must occur with great speed as well as accuracy. 
         [0004]    In the case of closures that must be applied with rotational force, a certain amount of torque must be applied to achieve the desired level of “cap tightness”. The required tightness is affected by many factors, including design details of the closure and container such as materials, certain dimensions, tolerances, and the methods of sealing to achieve adequate leak prevention, as well as the use of various methods of tamper-evidence. To achieve the required level of tightness, a torque must be exerted to rotate the closure while a force is exerted on the container to allow it to resist rotation. A number of different systems are well-known to exert a resistive force on the container. 
         [0005]    For containers that have non-round shapes (oval, square, rectangular, or similar) the machine components that position the container under the capping head are configured with shaped openings into which the container fits tightly enough to prevent rotation about the vertical axis of the opening receiving the closure, due simply to the non-round shape being constrained by the shaped pocket. 
         [0006]    For containers that have a circular shape centered on the vertical axis, some alternate means of resisting rotation must be applied. These may include the addition of high-friction (often resilient) materials used to line the pockets. A tensioning belt may be employed to apply side force against the container to improve “seating” into the lining material. 
         [0007]    When the container is very flexible, the side forces to seat the container may deform the container&#39;s side walls, which may damage or deform the container. If a certain small part of the container is especially resilient, it may be possible to design mechanical pieces to grip that resilient part. Alternately, by gripping evenly around the entire area of the container, it may be possible to apply enough force to resist rotation. However, both of these methods involve increased complexity and cost for the closure system, and are not always successful in accomplishing the resistance objective. 
         [0008]    It would desirable to have a system for container closure that could exert sufficient force to resist rotation of the container without risk of deforming or damaging the container, that could be applied to both non-round and round containers of a variety of sizes and materials, and that does not accrue the costs associated with systems involving numerous precisely allocated mechanical parts. 
       SUMMARY 
       [0009]    In certain aspects, the invention involves a device for container closure that includes a container holder with an opening through which air is drawn out of the container location so that the container is pulled toward the opening. 
         [0010]    In an aspect, a container handling system for applying closures to containers includes a container feed line and a capping station for receiving containers from the container feed line and applying closures thereto. The capping station includes a capping head configured to provide torque during closure application. A container holder is configured to resist container rotation. The holder includes an opening exposed to a container location and a device positioned to draw air from the container location through the opening to create a force the acts to pull the container toward the opening. 
         [0011]    In another aspect, a method for applying a closure to a container is provided. The method includes bringing the closure and the container in contact. Torque is applied to the closure. A vacuum force is exerted on the container to urge the container into contact with another member developing a frictional force that resists rotation of the container during the application of torque to the closure. 
         [0012]    In another aspect, a container handling system for applying closures to containers includes a container feed line and a capping station for receiving containers from the container feed line and applying closures thereto. The capping station includes a capping head configured to provide torque during closure application. A container holder includes a container engaging surface. A vacuum system is connected to the container holder that draws the container against the container engaging surface. The container engaging surface and vacuum system cooperate to inhibit rotation of the container during the closure application. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  illustrates an embodiment of a container closure system; 
           [0014]      FIG. 2  is an angled view of a container holder shown holding a container; 
           [0015]      FIG. 3  is a side view and force diagram of a container holder shown holding a container; 
           [0016]      FIGS. 4   a - 4   e  are different views of components of a vacuum plate that acts as a container holder; 
           [0017]      FIG. 5  is an embodiment of a container holder including a set of container guides; 
           [0018]      FIGS. 6 and 7  show an embodiment of a container holder utilizing side suction; 
           [0019]      FIG. 8  illustrates an exemplary pneumatic schematic; 
           [0020]      FIG. 9  illustrates an embodiment of a closure applying system; and 
           [0021]      FIGS. 10 and 11  illustrate an embodiment of a closure applying system. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]      FIG. 1  shows a container closure system according to one embodiment. Open containers approach a capping station  60  on an infeed conveyer  70  which uses an infeed screw  72 . Each open container moves from the infeed conveyer  70  to an infeed starwheel  74  and then onto a container holder  10  of a closure applying station. In this embodiment, the container holder takes the form of a vacuum plate assembly, but additional positioning and holding structure may also be provided. As a capper head  62  screws a closure onto the container, the vacuum plate assembly holds the container in place. The closed container exits the capping station  60  via a discharge starwheel  84  onto a discharge conveyer  80 . Multiple container holders and corresponding capper heads may be provided as shown, with the components rotating together around a central axis of the capping station during closure application. Other closure system configurations are also contemplated, including tangential infeed systems with no infeed starwheel, and single head cappers with intermittent infeed or manual infeed. 
         [0023]    Referring to  FIG. 2 , an exemplary container holder  10  is shown including a resilient ring  12  and a central opening  14 . The resilient ring  12  is set in a solid surface  18 , which is preferably a rigid material that is part of the container conveyance system. An edge  22  of the bottom surface of the container  20  surrounds the opening  14  and seats against the top of the ring  12 . Air is drawn through the opening  14  to create a force that will pull the container downward toward the resilient ring  12 . 
         [0024]      FIG. 3  shows a side view partial cross-section of a container holder. As air is drawn through the opening  14  in the direction of arrow  40 , the pressure gradient results in a downward force on the container  20  that pulls the container into more aggressive contact with the resilient ring  12 , increasing the force of the container  20  loading the ring  12 , and yielding higher frictional force resisting rotation thereby increasing the system&#39;s ability to resist sliding rotational movement of the container  20  relative to the holder  10 . 
         [0025]    As the closure  30  contacts the container  20 , the capping head  62  ( FIG. 1 ) exerts a rotational torque  42  on the closure  30 , which is also exerted on the container  20  in contact with the closure  30 . The torque  42  causes a force of friction  44  at the contact surface of the container  20  and the resilient ring  12 . The force of friction  44  is rotationally in the opposite direction from the torque  42 . Frictional torque  44  opposes torque  42 , resisting the rotation of the container. As the closure  30  moves clockwise while the container  20  does not, the closure  30  is applied and the container  20  is closed. A vacuum source  41  may be used to draw air through the opening  14 . 
         [0026]    A container holder which pulls a container downward by communication with the container bottom may be configured as shown in  FIGS. 4   a - 4   e .  FIGS. 4   a - 4   c  show a stainless steel vacuum plate  2  which includes an annular depression  8  shaped to hold the rubber disk  12  shown in  4   d  and  4   e . The annular depression  8  forms a volume that is bounded by an annular wall  11  spaced radially from a boss  13  in a center of the volume. Air is drawn through a vacuum outlet hole  14  which communicates with a vacuum pump (not shown). The vacuum outlet hole  14  extends through the boss  13  and is in communication with an interior vacuum passage  5  which in turn connects to an opening  4 . A set of cross-wise grooves  7  are cut into the surface of the boss  13  surrounding the opening  14  to help assure communication of the area beneath the container with the vacuum passage  5 . As air is drawn through the vacuum outlet hole  4 , air is drawn through the opening  4 , creating suction at the opening  14  to pull a container against the rubber disk  12 . 
         [0027]      FIG. 5  shows another embodiment of a container holder  10  using a vacuum plate  2 . Here, the container  20  is bracketed by a set of container guides  9 . The container guides  9  may be capable of movement (e.g., through the use of actuators) horizontally toward and away from each other to receive, hold and release the container  20 . Vacuum reaches the bottom of the container  20  through an interior vacuum passage that communicates with a vacuum pump through vacuum outlet hole  4 , as above. Container guides  9  may exert additional friction on the container  20 , or may simply be used to assure that the container  20  is properly positioned. 
         [0028]      FIGS. 6 and 7  show an embodiment of a container holder  10  where the opening  14  communicates with the side of the container rather than the bottom. Referring to  FIG. 6 , a bracket  50  is shaped to conform substantially to the side surface  24  of the container  20 . Air is drawn through opening  14 , which draws the container  20  in the direction of arrow  40 . Referring to  FIG. 7 , the surface of the bracket around opening  14  may include a pad of resilient material  13 . The horizontal force that draws container  20  against resilient pad  13  increases the force of the container loading the pad, thereby increasing the system&#39;s ability to resist sliding movement of the container  20  relative to the holder  10 . 
         [0029]    It is not necessary for the container holder to include a resilient surface. Any holder configuration that allows force from suction to create a force of friction when a rotational torque is exerted can resist rotational motion of the container and carry out the purpose of the present invention. 
         [0030]    Although the figures show a cylindrical container and a circular opening, the container may be of any shape, and the container holder adapted in shape if necessary to allow the force from suction to aid the container in resisting rotation. No particular shape of container nor any particular symmetry is necessary for the present invention. 
         [0031]    These configurations are applicable to single-head as well as multiple-head chuck-style cappers of both in-line and rotary configurations, as well as any other capper configured to use rotational force to apply closures to containers. 
         [0032]    In one embodiment, the pressure gradient resulting in a force from suction is created by means of either a central vacuum pump or by one or more orifice-type vacuum generators employing compressed air. Timing of application and release of the vacuum at each container position may be through a control system that employs either electrically or mechanically activated valves that are synchronized to the operating sequences of the particular capper to which them system is being applied (e.g., initiate vacuum after container has been delivered to the closure applying location, maintain vacuum during closure application and cease vacuum after completion of the closure applying operation so that the container can readily be moved out of the closure applying location to the outfeed or discharge conveyor). 
         [0033]    An exemplary pneumatic schematic for one embodiment is shown in  FIG. 8 , but many variations are possible. In the embodiment of  FIG. 8 , a pressure source  110  provides pressurized air (e.g., filtered, dry air under a pressure of about 90 psi) to a venturi pump  112 , which utilizes the pressurized air to draw air from the container holder  10 , as described above. A valve  114  (e.g., a drain ball valve) and a regulator  116  are used to control passage of pressurized air to the venturi pump  112 . 
         [0034]    Referring to  FIG. 9 , in one embodiment of a closure applying system having a single capping head (represented by dashed line  62 ) with multiple container locations  104  that move past the capping head in a sequenced manner, the container holder  10  is in a fixed location  100  of the capping station. A stationary vacuum system  102  is connected to the container holder  10  in a fashion similar to that described above. 
         [0035]    Referring to  FIGS. 10 and 11 , in a system with multiple capping heads (e.g., per  FIG. 1 ) each of the container locations would be constructed so that the vacuum could be triggered and maintained (e.g., by mechanical or electrical valving) during rotation of the plate holding the container locations. In some embodiments, a single vacuum source or multiple sources could be used. The timing of triggering of a vacuum for any given container location could be set to follow another operation, such as the bumping (e.g., via a pneumatic pusher) of the container into desired positioned seated against a side collar of the container location. In a single vacuum source embodiment, as each vacuum plate assembly is rotated into alignment with system  102 , a potential fluid path from the vacuum source  41  to the opening  14  in the holder is made. The vacuum can then be triggered (e.g., by mechanical or electrical valving), so that the vacuum can be triggered, the closure applied and the vacuum then terminated. 
         [0036]    It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation. Directional terms are given entirely for illustrational purposes, assuming the container to be upright and the closure to attach downward from above the container. However, one skilled in the art will recognize that up, down, vertical and the like are relative terms and that many other orientations are feasible. The above description allows for many variations, and one skilled in the art will find myriad changes can be made within the spirit and scope of the claimed invention, which is intended to be limited only by the claims and operation of law.