Abstract:
A system for sealing threaded containers. The system includes a clutch-free spindle assembly which is easily disassembled and cleaned. The special interface between the exterior surface of the cap an the gripping jaws of the chuck allow the system to operate without the moving parts and complications that attend the use of clutch. The spindle assembly features an easily adjustable stop arm and a quick release pin for removing and cleaning the chuck. The chuck has several passageways for the rapid infusion of cleaning fluid.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     Machines for applying closures to containers are well known and widely used. The present invention relates to the application of threaded closures to containers having threaded necks, and is particularly directed to the application of closures to containers which hold consumable liquids, such a milk. 
     It is nearly impossible with practical cleaning systems to remove all milk residues and deposits from the milk contact surfaces of milk bottling and capping equipment. One of the major difficulties with most currently used equipment, closures and containers, is the need to thoroughly and frequently clean the equipment so that the contents of the containers is not contaminated. 
     Overtightening or stripping of the threaded connection between the closure and the container is also a problem. Applying threaded closures to milk containers is particularly problematic because milk is lubricious, making stripping a significant problem in milk bottling operations. 
     Many bottlers, for convenience and to reduce costs associated with shipment of empty containers, blow mold containers on-site. Because many bottlers do not have expertise in blow molding operations and, in particular, tooling maintenance, serious problems can arise, such as bottles being molded to configurations which significantly vary over time. In some instances, bottlers have other difficulties maintaining consistent quality in the manufacture of their bottles. Problems such as excessive flash, mismatching of mold components, excessive parison pleating, and non-round openings are common in on-site blow molding operations. While caps are generally molded to relatively precise and consistent dimensions, blow molded bottles generally are not, particularly bottles made by bottlers who blow mold bottles on-site. To provide a reliable closure on bottles of varying dimensions and quality is a difficult challenge for cap suppliers. 
     The present inventions have particularly beneficial application in turret-type capping equipment of the general type shown and described in the following U.S. Pat. Nos. 3,771,284; 5,197,258; and 5,473,855. However, the spindle assembly and related rotation inducing equipment could be used in other types of machinery. When used with turret-type machinery, a cap feeder assembly is used to bring a cap into initial proximity to a moving container neck. A conveyer brings the container into engagement with the cap and delivers the container (with the cap loosely disposed atop the container) to a capping station on the turret. The container support of the turret holds the container in vertical alignment with a spindle assembly. When the container support engages a cam, the container (with a cap loosely positioned on the container neck) is lifted into engagement with a chuck at the lower end of a drive shaft of the spindle assembly. The drive shaft of the spindle assembly has a chuck carried by the lower portion of the spindle, which grips the cap as the bottle and cap are brought into engagement with the chuck. 
     When the turret rotates, a pinion gear at or near the upper end of the drive shaft of the spindle assembly delivers torque to the drive shaft due of the engagement of the pinion gear with a stationary and much larger gear wheel mounted atop the turret. In a typical turret capping machine the gear wheel is continuous. However, as shown in U.S. Pat. No. 5,473,855, the gear wheel may be less than a full circle, and torque may be delivered to the drive shaft intermittently. The interface where torque is transferred from gripping jaws on the chuck to knurls formed on the outside surface of the cap (i.e., the chuck/cap interface) is designed to prevent stripping of the cap as it is tightened onto the threads of the container. 
     In one embodiment described herein, a cap is designed to have a series of areas where some of the knurls on the exterior of the skirt portion of the cap extend radially outwardly beyond other knurls, such that the extended knurls are the primary points of contact with the gripping jaws of the chuck. If the cap tightens before the spindle assembly stops rotating, the extended knurls deflect and allow continued rotation of the chuck, even though the cap has stopped rotating, thus preventing the stripping of the threads of the cap relative to the threads on the container neck. 
     Thus, the knurls on the cap and splines on the jaws inside the chuck as described herein are specifically designed to simplify and facilitate the application of threaded caps to threaded containers. The chuck/cap interface described and claimed herein is designed to reduce the number of moving and fixed parts by eliminating the need for a clutch mechanism in a capping spindle. This objective is achieved the a chuck and cap combination that includes a very simple and easily cleaned chuck and a cap with a specially designed surface that is contacted by the jaws of the chuck. 
     Furthermore, the simplicity of chuck described and claimed herein significantly reduces down time needed to clean and disinfect the capping machine and reduces the chance of unwanted bacteria from making its way into any bottles. 
     These and other objects and advantages of the present invention will be better understood upon a reading of the following specification read in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a turret with a plurality of spindle assemblies made in accordance with the present inventions; 
         FIG. 2  is a cross-sectional view of a cap suitable for use in connection with the present inventions; 
         FIG. 3  is an enlarged plan view of knurls on the exterior of a cap made in accordance with the present inventions; 
         FIG. 4  is an exploded perspective view of a spindle assembly made in accordance with the present inventions; 
         FIG. 4A  is an assembled perspective view of the spindle assembly shown in  FIG. 4  with a chuck attached; 
         FIG. 5  is a side elevational view of a ring forming a part of the spindle assembly shown in  FIGS. 4 and 4A ; 
         FIG. 6  is a plan view of the ring shown in  FIG. 5 ; 
         FIG. 7  is an exploded view of a chuck made in accordance with the present inventions; 
         FIG. 8  is a cross-sectional view of the chuck housing shown in  FIG. 7 ; 
         FIGS. 9 and 10  are enlarged end views of a jaw of the chuck shown in  FIG. 7 ; 
         FIG. 11  is a perspective view of the set of four jaws shown in  FIG. 7 ; 
         FIG. 12  is a plan view of an actuator which is part of the chuck shown in  FIG. 7 ; and 
         FIG. 13  is a side elevational view of the actuator shown in FIG.  11   
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a turret assembly  10  with several capping stations. Each capping station includes a spindle assembly  14  held in place by a pair of support plates  16  and  18 . The spindle assembly includes drive shaft  12  which is held and guided by an upper support plate  16  and a lower support plate  18 . The support plates  16  and  18  are connected to the turret assembly  10  by a spindle support arm  20 . A small pinion gear  22  is affixed to the upper end of the drive shaft  12 , and a chuck  24  (shown in detail in  FIGS. 4 and 4A ) is connected, by a quick-release pin  25 , to the lower end of the drive shaft  12 . Attached to the lower support plate  18  is a hinged stop arm  26  which engages the handle of a bottle  28  to prevent rotation of the bottle as a cap  30  (shown in detail in  FIGS. 2 and 3 ) is tightened onto the bottle  28 . 
     As the turret  10  rotates in the direction of the arrow shown in  FIG. 1 , a bottle support  32 , carried by the turret assembly  10 , engages a cam  34 , and lifts each bottle  28  upward and causes the cap  30  to engage the chuck  24 . The pinion gears  22  are in continuous engagement with a large fixed gear wheel  23  which does not rotate with the movement of the turret assembly  10 . The engagement between the pinion gears  22  and the gear wheel  23  supplies the torque needed to tighten a cap  30  onto a the threaded neck of a bottle  28 . 
       FIG. 2  is a cross-sectional view of a cap  30  having a ratchet ring  36  extending from the bottom portion of a skirt  38 . The cap  30  has four threads,  40 ,  42 ,  44  and  46 , all of which are at least partially visible in FIG.  2 . The cap  30  includes an integral plug  48  which has a conical exterior. 
       FIG. 3  is an enlarged plan view of knurls  50  which extend generally in a vertical direction from the lower portion of the skirt  38  to a point near the top  52  of the cap  30 . The knurls  50  include three different kinds of knurls, i.e., a series of several inner knurls  54  extending a first radial distance D 1  from the center of the cap; intermediate knurls  56  extending a second radial distance D 2  from the center of the cap; and outer knurl  58  extending a third radial distance D 3  from the center of the cap. Two outer knurls  58  are adjacent to one another, and are flanked by an intermediate knurl  56  on each side of the pair of outer knurls  58 . The combination of two outer knurls  58  and two intermediate knurls  56  define a region  60  of primary jaw engagement. There twelve regions  60  of primary jaw engagement equally spaced around the circumference of the  30  cap. 
       FIGS. 4 and 4A  are exploded and assembled views, respectively, of a spindle assembly  14 . A drive shaft  12  extends down the center of the spindle assembly  14  and is supported by an upper plate  16  and a lower plate  18 . A pair of standoffs  66  separate the plates  16  and  18 . A pinion gear  22  is rigidly affixed to the upper end of the drive shaft  12 .  FIG. 4A  shows a chuck  24  connected to the lower end of the drive shaft  12  by a quick release pin with a ring at one end. 
     The drive shaft  12  is held in place by a lower lock collar  68  which connects to the drive shaft  12  below the lower surface of the lower plate  18 . An upper lock collar  70  is attached to the drive shaft  12  at a location which is adjacent to the underside of the upper plate  16 . The lock collars  68  and  70  resist upward forces applied to the drive shaft  12  when a cap  30  is brought into engagement with the chuck  24 , which occurs when a bottle  28  (with a cap loosely carried atop the bottle) is lifted by the cam  34 . 
     A hinged stop arm  26  is supported by an outer ring  72 . The outer ring  72  is held in place below the lower plate  18  by an inner ring  74 . The inner ring  74  is connected to the lower plate  18  by a single bolt  76  and a pair of dowel pins  78 . The ring  74  is prevented from rotating by the bolt  76  and the dowel pins  78 . This arrangement allows for quick adjustment of the rotational position of the stop arm  26 , because the bolt  76  is on the outwardly facing side of the lower plate  18  and is therefore easily accessible by a service person. Loosening the bolt  76  will allow the entire inner ring  74  to drop and release the grip that it has on the outer ring  72  so that the stop arm  26  may be positioned at any radial position around the drive shaft  12 . The stop arm  26  is intended to engage the handle on a container to prevent the container from rotating as the drive shaft  12  and chuck  24  apply torque to a cap on the container. 
       FIGS. 5 and 6  show details of the inner ring  74 . The upper surface  75  of the inner ring  74  has three holes, a first threaded hole  80  and two unthreaded holes  82 . The unthreaded holes  82  are intended to engage the dowel pins  78  while the threaded hole  80  is intended to engage the bolt  76  when the ring  74  is attached to the underside of the lower plate  18  in combination with the outer ring  72 . 
       FIGS. 7 and 8  show the chuck  24 . A chuck housing  84  has a stem  86  with a through hole for receiving the quick release pin  25 . A main recess  88  is formed at a lower side of the chuck  24 . Four equally spaced passageways  90  extend through the upper portion of the chuck housing  84 . Similarly, the chuck housing  84  has a series of four lateral passageways  92  which extend through the outer portion of the chuck housing  84 . The passageways  90  and  92  allow for the free flow of cleaning fluid so that the chuck housing may be cleaned completely and quickly. 
     Four cap gripping jaws  94  fit into the main recess  88  in the chuck housing  84 . Each jaw  94  is held in the main recess  88  by a combination of pivot screws  96 , which extend with some clearance into bores  98  formed in the outside wall of each jaw, and C-shaped spring  97 . One pivot screw  96  provides vertical support for each jaw  94 , the spring  97  urges all of the jaws radially outwardly so as to keep the each jaw in engagement with its respective pivot screw  96 . Each of four pivot screws  96  extends through the outer wall of the chuck housing  84  such that an unthreaded portion  99  extends inwardly from the inner wall of the chuck housing and into a bore  98  formed on the outer surface of each gripping jaw  94 . The bore  98  extends into but not through the cap gripping jaw  94 . The diameter of the unthreaded end  99  of the pivot screw  96  is somewhat smaller than the diameter of the bore  98  such that each gripping jaw may pivot repeatedly about the unthreaded portion of the pivot screw  96  by which the jaw is supported without binding. 
       FIGS. 7 ,  12  and  13  show a jaw actuator  100  which is used to cause the jaws  94  (See  FIG. 7 ) to pivot together, respectively, about the pivot screws  96  which support the jaws  94 . As can be seen in  FIGS. 7 ,  9  and  10 , each jaw  94  has an upper quadrant shaped plate-like section  102  which extends radially inwardly from a vertical wall  104 . Wall  104  is generally cylindrical in shape and has vertical splines  106  spaced at about 6 degrees on center. Each spline  106  is preferably comprised of two main longitudinal surfaces  109  and  111 , which are disposed at about 90 degrees from each other, and which are joined by a rounded surface  115  having a radius (“R” in  FIG. 9 ) of about 0.015 inches. The splines  106  preferably extend inwardly from the inside surface of the jaw a distance of about 0.04 inches. 
     The interaction between the knurls  58 ,  56  and  54  (the outer knurls  58  in particular) and the splines  106  is important in that this chuck/cap interface eliminates the need for a complex clutch mechanism. The splines (particularly when the cap is made of low density polyethylene—LDPE) give way and allow slippage of the chuck at about 35 inch-pounds of torque, when a four-thread cap like the one shown in  FIG. 2  is used on a blow-molded container neck. A four thread cap is preferred because with such a cap only a small amount of rotation is required to tighten the cap on to the bottle neck. The rounded shape of the inner tips of the splines and the rounded shape of the tips of the knurls produces a minimum amount of visible marring on the knurls, even when high density polyethylene—HDPE is used to make the cap. The relative spacing as well as the shape of the knurls and splines is also an important factor in achieving a repeatable torque of about 35 inch-pounds, and not much more than that. In the embodiment cap show in FIG.  2  and the jaws shown in  FIGS. 7 ,  9 ,  10  and  11 , there is an integral-multiple relationship of the circumferential spacing of the splines  106  and the regions  60  of primary cap engagement. In particular, by way of example, the splines are spaced at 6 degrees, while there are twelve regions  60  of primary cap engagement, i.e. a frequency of one every 30 degrees. Thus the frequency of regions  60  to splines  106  is 30:6 or 5. 
     The upper quadrant shaped plate-like section  102  of each jaw  94  is preferably disposed at a slight angle (about 4 degrees) with respect to horizontal, and the outside surface of the wall  104  is comprised of two conical sections, including an upper conical section  105  making an angle of about 83 degrees with respect to horizontal, and an axially longer lower conical section  107  disposed at about 86½ degrees from horizontal. 
     The four upper quadrant shaped plate-like sections  102  of the gripping jaws  94  converge to define a central opening  108  which is slightly larger in diameter than the neck  10  of the jaw actuator  100 . The jaw actuator  100  includes a guide piston  112  which fits closely, but moves freely, within a guide cylinder  114  in the chuck housing  84 . 
     The guide piston  112  is joined to an actuator plate  113  by a reduced-diameter neck  110 . A central core passageway  118  extends from the upper end of the guide piston  112  to the lower side of the actuator plate  113 , such that the passageway  118  passes all the way through the actuator  100  from one end to the other. Small vent holes  117  are formed in the upper end of the guide cylinder  114  to avoid pressure variations within the guide cylinder  114  resulting from movement of the guide piston  112  in the guide cylinder  114 . A set of holes  120  are formed in the actuator plate  113 , and the holes  120  together with the central opening  118  form pathways for the free flow cleaning fluid, making the actuator, the chuck housing  84  and the jaws  94  easy to keep clean. 
     As a container with a cap loosely fitted onto the neck thereof is brought upwardly into engagement with the chuck  24 , the cap on the container contacts the lower surface  116  of the jaw actuator  100 . As the cap and container continue to be pushed upwardly, and with the chuck turning constantly (or intermittently, depending upon the design of the turret) the jaw actuator  100  causes the jaws  94  to pivot about the pivot screws  96  such that the upward force of the cap and container result in a lateral gripping force exerted by the jaws  94  on the splined surfaces of a cap  30  (See FIG.  2 ). Thus, each jaw is urged outwardly to a first “jaws open” position by the spring  97  (See FIG.  7 ). However, when a cap-carrying container is urged upwardly, the actuator  100  causes the jaws to pivot into a second “jaws closed” position. At the same time as this gripping action occurs, rotational force and rotational movement results from the engagement of the pinion gear  22  with the gear wheel  23 , as shown in FIG.  1 . 
     While specific embodiments of the inventions have been shown and described, it is believed that numerous alternatives, modifications, and variations of the embodiments shown and described herein may be realized by persons of ordinary skill in the arts to which the inventions pertain, and such persons may devise a number of such alternatives, modifications, and variations of the embodiments shown and described herein without departing from the spirit and scope of the appended claims.