Abstract:
A closure system for a container reduces the needed torque for assembly by minimizing frictional resistance to rotation of the closure into its desired alignment with the container before the closure is driven home onto the container neck. The reduction in the torque resistance during the application of the closure allows the rotary filling machinery to work within its torque limits and minimizes damage to the parts during the filling and sealing operation in a bottle filling line.

Description:
FIELD OF THE INVENTION  
       [0001]     The field of this invention is closures for bottles and more particularly for bottles capped with a rotary capper.  
       BACKGROUND OF THE INVENTION  
       [0002]     High speed filling lines are commonly used to fill a variety of containers of various shapes and sizes. The machinery typically positions the receiving container for the product in alignment with a fill nozzle or outlet. After the product is delivered, a closure is put on to seal the bottle. The capping machinery has controls built in that are used in placement of the closure. In order to assure rapid and secure placement of the closure, the equipment needs to be able to deliver certain forces and torques to secure the closure. For closures that secure by snap or interference fit, there is a balance that needs to be drawn between getting a secure slip free contact between the container and the closure and the limits of the machinery to deliver the desired force and keep the filling line moving at the desired speed. If the clearances are too tight the resulting required forces can get too high for the capping equipment. This can result in an incomplete placement of the closure on the container and potential product leakage along the distribution chain.  
         [0003]      FIGS. 1-6  illustrate this problem in a prior art bottle that uses a snap fit closure onto the neck of an elongated bottle. Referring to  FIG. 1 , the bottle  10  has a neck generally indicated at  12  at its top end. A support ring  14  defines the beginning of the neck  12  and features an upwardly oriented shoulder  16 . A ring  18  located above support ring  14  defines an undercut radial surface  20 . Above ring  18  and working up to the top of the neck  12  are a pair of transition surfaces  22  and  24  that ultimately lead to the top  26  of the neck  12 . The closure  28  is shown above the bottle  10  in the position that the capping machinery would hold it before driving it home onto the neck  12 . Closure  28  has an outer surface  30  and an inner surface  32 . Inner surface  32  has a series of circumferentially spaced inwardly oriented projections  34  that each features a radial surface  36  adjacent a tapered and downwardly extending surface  38 . Inner surface  32  also features a longitudinally extending and generally rectangular shaped key  40  having a taper  42  at its lower end. A ring  44  is disposed concentrically to inner surface  32  and has a gradual exterior outward taper  46 . Neck  12  further comprises a longitudinally oriented gap  48  which is wider than key  40 , for reasons that will be explained below. Closure  28  has an outlet  50  which can be any known design for getting the product out of the bottle  10  when it is placed in use.  
         [0004]     With the components now having been described, the process of assembling the closure  28  to the bottle  10  will now be described and in the process, its limitations will be more readily understood. Those skilled in the art will appreciate that the machinery that is not shown receives a closure  28  in a random orientation with regard to the location of key  40 . Stated differently, key  40  may or may not be axially aligned with gap  48  when the closure  28  is brought down on the neck  12 . Comparing  FIGS. 1 and 2 , it can be seen that the closure  28  has been brought closer to the neck  12  and that closure  28  has been rotated about its vertical axis to change the orientation of the key  40  with respect to the gap  48 . In  FIG. 2 , they are in further misalignment than they were in  FIG. 1 .  FIG. 3  compared to  FIG. 2  shows further downward movement of closure  28  as well as a further rotation of about 90° about its vertical axis as compared to the  FIG. 2  position. In  FIG. 3 , tapered surface  38  has landed on transition surface  22  of neck  12 . Taper  42  at the lower end of key  40  has landed on tapered surface  25  just below the top  26  of the neck  12 . It is apparent that key  40  is still misaligned with gap  48  in this position. Tapered surface  46  of ring  44  is inside the top end  26  and on the verge of contact with the inside wall of the neck  12 . Now comparing  FIG. 4  to  FIG. 3 , the closure  28  has been pushed further down but not rotated by much. At this point radial surface  36  has been snapped to below radial surface  20 . Tapered surface  46  of ring  44  is now in contact with the inside surface of the neck  12  just below end  26 . Key  40  is now straddling ring  18 . Those skilled in the art will appreciate that subsequent effort to rotate the closure  28  after being forced down to the  FIG. 4  position will engender significant resistance from several contact points with neck  12 . The key  40  extending over ring  18  will resist rotation as will the rubbing of ring  44  inside the upper end  26  of the neck  12 . Finally, there is an upward force that forces radial surface  36  of closure  28  up against radial surface  20  of ring  18  on the neck  12 . This residual force results from the dimensions of the components and the driving of the closure  28  down over ring  18 . The problem in the past with this design is that the equipment is either torque limited or has settings that limit applied torque to the closure  28  to avoid component damage by forcing a fit in situations where the components may not be totally in axial alignment. The compound effect of these interference fits that are desirable in assuring the securing of the closure  28  to the bottle  10  become a disadvantage during the filling process. Comparing now  FIG. 5  to  FIG. 4 , it can be seen that the closure is rotated about its longitudinal axis to bring key  40  closer to gap  48 . The assembly is finished when key  40  snaps off ring  18  and settles into gap  48  to rotationally lock the closure  28  to the neck  12 .  
         [0005]     The present invention improves the configuration of the components to greatly reduce the required torque to assemble them while, in the end, allowing them to be securely connected to each other as in the past. One way this is accomplished is an emphasis on getting the components into their final alignment positions at a time when less interference contact exists, thus greatly reducing the required torque for rotating the closure into its final position. In the end the closure is just as secure as in the prior art design but the assembly process has been optimized in view of the low applied torque required to reach the final made up position of the components. These and other advantages of the present invention will more readily be understood by those skilled in the art from a review of the remaining drawings and the associated description of the preferred embodiment as well as the claims for the invention that appear below.  
       SUMMARY OF THE INVENTION  
       [0006]     A closure system for a container reduces the needed torque for assembly by minimizing frictional resistance to rotation of the closure into its desired alignment with the container before the closure is driven home onto the container neck. The reduction in the torque resistance during the application of the closure allows the high speed filling machinery to work within its torque limits and minimizes damage to the parts during the filling and sealing operation in a high speed filling line. 
     
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
       [0007]      FIGS. 1-6  are a series of views showing the assembly in progress of applying the closure to the neck of a container in the prior art design; and  
         [0008]      FIGS. 7-12  are sequential views of the present invention showing the closure being applied to the container. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0009]     Referring to  FIG. 7 , the container  50  accepts the closure  52 . Container  50  has a neck  54  having an optional ring  56  that features an upper surface  58  that, if used, does not necessarily support the closure  52 . Lower end  60  of closure  52  ultimately comes to be supported off of surface  58 , as shown in  FIG. 12  or can lay close to it without contact. Neck  54  further comprises a circumferential recess  62  disposed between rings  64  and  66 . Ring  66  has a ramp  68  adjacent an indexing gap  70  that spans rings  64  and  66  and recess  62 . Closure  52  had an interior circumferential surface  72  featuring a circular projection  74  that may be continuous or in discrete segments. Inner ring  76  has an exterior tapered surface  78 . A longitudinally oriented indexing key  80  has a tapered lower end  82  that extends down to a point short of projection  74 . Closure  52  has an outlet  84  of a type known in the art. Those skilled in the art will appreciate that indexing key  80  can be on the neck  54  and indexing groove  70  can be on the closure  52  as that option is a transposition of parts that function in the same way. In the same manner the rings  64  and  66  and the recess  62  between them can be transposed with projection or bead  74  within the scope of the invention.  
         [0010]      FIG. 8  shows the closure.  52  brought closer to the container  50  while it is rotated about a vertical axis. There is still no contact at this time. In  FIG. 9  the closure has been lowered and rotated a further amount. Note that the key  80  is still out of alignment with the gap  70 . However, at this time the circular projection  74  has passed ring  66  and landed in recess  62  between rings  64  and  66  for temporary support in that position. The lower end  82  of the key  80  is just above or right at ring  66 . Tapered surface  78  of ring  76  is inside the upper end  86  of the neck  54  and preferably out of contact or in light guiding contact with the inside surface  88  of the neck  54 . Lower end  60  of closure  52  is above surface  58 .Having reached this position, further relative rotation can occur with minimal resistance as compared to the prior design described in  FIGS. 1-6 . For one thing the key  80  is not straddling any ring such as  64  or  66  even when it is misaligned with the gap  70 . Projection or bead  74  having jumped over ring  66  on the way down into recess  64  now loosely fits in that recess  64  and uses rings  64  and  66  for guides, as the closure  52  is further rotated, as shown in  FIGS. 10 and 11 . Finally, the closure is guided for rotation by the extension of ring  76  into upper end  86  but without significant or any dragging of tapered surface  78  on the inside surface  88  of neck  54 . In essence the closure is guided at three locations off of neck  54  as the closure  52  is rotated to bring the key  80  into alignment with gap  70 . These three points of support for low resistance to applied torque are the disposing of projection  74  loosely within recess  64 ; letting lower end  82  of key  80  ride on or slightly above ring  66  and guiding the top of closure  52  within neck  54  by the extension of ring  76  into end  86  when tapered surface  78  is just out of touch or lightly contacting inside surface  88  of neck  54 .  
         [0011]     As shown in  FIG. 11 , the  80  has been turned into alignment with gap  70  to allow the closure  52  to now be pushed down as shown in  FIG. 12 .By doing that, the lower end  60  comes to rest on or near support surface  58 .Projection  74  has jumped out of recess  62  to a position under ring  64  and taper  78  of ring  76  is in an interference contact with inside surface  88  of neck  54 . It should be noted that the movement in  FIG. 12  involves no rotation as alignment of the key  80  with the gap  70  has previously been achieved. In this position ring  64  retains projection  74  to hold the closure  52  to the neck  54 .  
         [0012]     Those skilled in the art will appreciate that a number of initial orientations of the key  80  to the gap  70  are possible when the  FIG. 9  position is initially reached. The purpose of the ramp  68  is to push closure  52  in a clockwise direction to begin the orientation process until key  80  winds up in alignment with gap  70 . Of course if there is perfect initial alignment between key  80  and gap  70  the closure is simply pushed down as the machinery senses resistance to rotation because key  80  will not jump out of gap  70  and over ramp  68  without an amount of torque that will trip a switch on the machinery against over-torque. At that point, the equipment will simply push the closure  52  straight down. To reduce resistance to rotation even further, the neck  54  and the closure  52  internals can be made from a lubricious material or can have a small amount of a lubricant applied to the contacting surfaces to further reduce resistance to turning to seek the proper orientation before pushing the closure  52  to its final position on the neck  54 .  
         [0013]     The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the invention.