Abstract:
Disclosed are valve actuator assemblies for high speed bottle filling machines. These actuators have a shaft that is pivotable on its longitudinal axis, a linkage fork connected to the shaft to pivot therewith, and a follower arm coupled by a magnetic coupling to the shaft. The magnetic coupling helps reduce carbon dioxide leakage. There may also be a second set of magnets which define pivoting dwell positions.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    Not applicable. 
       STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates to high speed equipment for filling bottles or other containers with liquids (especially carbonated liquids). More particularly it relates to actuator assemblies that control valve positioning in such equipment. 
         [0004]    It is well known to fill bottles and other containers with liquids using automated equipment. For example, Krones AG commercializes a line of “Mecafill VKP” automated filling machines. 
         [0005]    Fillers of this type progressively fill bottles at high speed as a line of the bottles are caused to move to, around and then away from the machine. Typically, there is an axially movable linkage structure and filling chamber over the top of each bottle as it is being filled. Controlled axial valve movement in each such filling chamber facilitates removal of air in the bottle and filling of the bottle with a beverage (or other liquid) and often carbon dioxide. 
         [0006]    This is typically achieved by having the valving structure mechanically linked to an actuator, which in turn is pivoted by a cam follower arm. See e.g. the valve actuator 78 in U.S. Pat. No. 5,960,838. 
         [0007]    One problem that has arisen in using such equipment is that various models of this type of equipment have a tendency to develop leakage of carbon dioxide over time. For example, leakage can occur along a passageway between a follower arm and a linkage fork shaft due to wear. 
         [0008]    Another source of linkage is that many machines of this type use springs to hold various parts together or against each other. Those springs can lose their biasing force over time, and thereby lead to leakage. 
         [0009]    Such leakage wastes carbon dioxide (and thus somewhat increased cost). Moreover, there is increasing regulatory interest in avoiding unnecessary carbon dioxide emissions (due to climate change concerns). 
         [0010]    In various contexts magnetic couplings have been used as one means of transferring motion from one assembly part to another. See e.g. U.S. patent application publication 2009/0071566, and U.S. Pat. Nos. 4,163,464, 4,671,486, 5,927,564, and 6,179,016. 
         [0011]    In any event a need still exists for improved valve actuators for use with high speed automatic bottle filling equipment. 
       SUMMARY OF THE INVENTION 
       [0012]    In one aspect the present invention provides a container (typically a bottle) filling machine having a valve actuator assembly. The actuator assembly has a shaft that is pivotable on its longitudinal axis (preferably in a housing bore), a linkage (e.g. a fork) connected to the shaft to pivot therewith, and a follower arm coupled to the shaft by a magnetic coupling such that pivoting of the follower arm causes pivoting of the shaft, and thus pivoting of the linkage. The follower arm may in turn be pivoted by a driver (preferably a cam driver) of the container filling machine, and the linkage assists in controlling movement of a valve assembly of the container filling machine. 
         [0013]    In a preferred form the magnetic coupling includes an outwardly (radially or axially outwardly) positioned magnet that is linked to the follower arm to pivot therewith, an inwardly (radially or axially inwardly) positioned magnet that is linked to the shaft to pivot therewith, and a stationary housing wall positioned between the outwardly positioned and inwardly positioned magnets. The magnets are preferably permanent/hysteresis type magnets. With a hysteresis type construction some of the drag properties are preferred. 
         [0014]    The magnets may be of single piece construction (e.g. multi-polar), or an array of segmented arcs, or an array of segmented rectangular slabs. One such an array of segmented pieces has adjacent pieces of alternating polarity. 
         [0015]    In an especially preferred form there is also a second set of magnets. In this form the housing extends around the shaft and there is a guide magnet positioned outward (e.g. radially outward) of the housing so as to pivot with the follower arm. There are also two docking/indexing magnets spaced (e.g. circumferentially spaced) around the housing. The guide magnet preferably functions in a bi-stable manner. In this regard it will tend to dwell adjacent either of the docking magnets when it is moved near them. However, between the circumferential docking positions there is little resistance to the pivoting. 
         [0016]    The guide magnet has a first polarity and the docking magnets both have a second polarity. This second set of magnets helps the filler valving stay in its closed position without additional forces being required from springs or the like. 
         [0017]    In another aspect of the present invention there is provided a container filling machine having a valve actuator assembly. In this aspect the valve actuator assembly has a shaft that is pivotable on its longitudinal axis, a linkage connected to the shaft to pivot therewith, and a follower arm coupled to the shaft such that pivoting of the follower arm causes pivoting of the shaft, and thus pivoting of the linkage. 
         [0018]    The follower arm is pivotable by a driver of the container filling machine, the linkage assists in controlling movement of a valve assembly of the container filling machine, and a stationary housing extends around the shaft. A guide magnet is positioned outward of the stationary housing and pivots with the follower arm, two docking magnets are positioned on the stationary housing in spaced fashion, and the guide magnet will tend to be attracted to a docking magnet when pivoted adjacent thereto. 
         [0019]    In yet another aspect of the present invention there is provided a valve actuator assembly suitable for use in such container filling machines. The assembly is capable of transferring motion from a cam driver to a valve seal. It has a housing having a central bore, a shaft that is pivotable in the bore on its longitudinal axis, a linkage fork connected to the shaft to pivot therewith, and a follower arm coupled to the shaft via a magnetic coupling such that pivoting of the follower arm structure can cause pivoting of the shaft, and thus pivoting of the linkage fork. The magnetic coupling is preferably of the above type, and there preferably is also such a second set of magnets for providing guided docking as described above. 
         [0020]    The present invention reduces carbon dioxide leakage and also reduces maintenance issues for automated container filling equipment. It avoids the need for an extra aperture to link a cam follower to the sealing valve, thereby avoiding one possible leakage pathway. Further, the use of the second set of magnets to index and hold the valving at a firm seal position reduces leakage during the filling process due to weakening of a spring over time. 
         [0021]    The actuators of the present invention can be produced at commercially reasonable cost. Further, they are capable of being incorporated as replacement parts in connection with a variety of existing high speed filling equipment models, without requiring substantial modification to the remainder of the machine or the actuator. 
         [0022]    These and still other advantages of the present invention will be apparent from the detailed description and drawings. Of course, what follows is merely a description of preferred embodiments of the present invention. To assess the full scope of the invention the claims should be looked to. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a front elevational view of an actuator of the present invention attached to a filling chamber portion of a conventional Krones type bottle filler machine; 
           [0024]      FIG. 2  is a right side elevational view thereof; 
           [0025]      FIG. 3  is a perspective view of the  FIG. 1  actuator assembly; 
           [0026]      FIG. 4  is an elevational view thereof, with a portion partially in section; 
           [0027]      FIG. 5  is another elevational view thereof; 
           [0028]      FIG. 6  is a sectional view taken along line  6 - 6  of  FIG. 4 ; 
           [0029]      FIG. 7  is a vertical sectional view of the  FIG. 3  actuator; 
           [0030]      FIG. 8  is a sectional view taken along line  8 - 8  of  FIG. 7 ; and 
           [0031]      FIG. 9  is a second embodiment shown in a section somewhat analogous to  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]      FIG. 1  depicts the most relevant portion of a bottle filler machine of the present invention. There is a product (e.g. soda and carbonation) tank  5  in which is mounted a valving assembly  6  that is designed to open and close a soda bottle or the like during a filling process. The valving assembly has a contact surface  7  to transfer motion from a valve actuator  8  of the present invention to the sealing portions of the valving assembly  6 . 
         [0033]    Valve actuator  8  could be a replacement for a part like part 78 in U.S. Pat. No. 5,960,838. Alternatively and more preferably it could replace the mechanical actuator assembly of a Krones Mecafill high speed automated bottle filler. 
         [0034]    The actuator  8  is designed to pivot a forked linkage  11  against and away from the contact surface  7 . When driven into contact with the contact surface  7  the actuator drives the valving  6  to a seal position against the bottle being filled. When moved away from the contact surface  7  the actuator allows a spring to release the seal away from the bottle top. 
         [0035]    Turning now to  FIGS. 2-8 , in the preferred actuator  8  there is a follower roller  30  suitable to be contacted by a conventional cam drive (not shown) of the filling machine to cause a forward and back pivoting motion around longitudinal pivot axis A. This pivots shaft  28 , which in turn pivots forked linkage  11 . 
         [0036]    In this regard, contacting the roller  30  drives a follower arm  38 . This then drives the shaft  28  via arrays  42  and  44  of magnets which form a magnetic coupling. Note that no part of the follower arm  38  needs to pierce the sealed outer housing hub  10 . Thus, there is no need to seal such an aperture, or risk that the seal will wear over time and thus leak. 
         [0037]    With particular reference to  FIG. 7 , note that there is an outer housing hub  10  linked via bolts  58  to the follower arm  38  to rotate therewith. The follower arm  38  supports a roller shaft  32  on which spins the follower roller  30 . The roller  30  is held on shaft  32  via a lock washer  46  and a nut  60 . 
         [0038]    As is evident from  FIG. 8 , the outer hub  10  retains an array  42  of radially outer magnets. This can be an array of six 60° arcs of alternating polarity magnets. They can be held in place via an outer magnet shield  18 . 
         [0039]    Similarly, an inner housing hub  14  supports an array  44  of inner magnets. As shown in  FIG. 8  these can also be six 60° arcs of alternating polarity magnets. There is also an inner shield  16  to retain the array  44  of inner magnets in place and protect them. 
         [0040]    The south polarity magnets in array  42  will seek to rotationally align with the north polarity magnets in array  44 , and the north polarity magnets in array  42  will seek to rotationally align with the south polarity magnets in array  44 . 
         [0041]    It will be appreciated that because the inner array  44  seeks to keep its rotational alignment with respect to the outer array, pivoting of the roller  30  in response to cam drive causes the rotation of the hub  10 , and then will cause rotation of shaft  28 , even in the absence of a mechanical coupling between the hub and shaft. 
         [0042]    As another important aspect of the invention, movement of the follower arm  38  is magnetically biased towards one of two docking positions by virtue of a second set of magnets  36 / 39 . In this regard, the outer housing hub  10  has coves for receiving and retaining four button shaped docking magnets  39 A-B. See  FIG. 6 . They are retained in the coves by magnet covers  40 . 
         [0043]    There is also a stationary housing  55  which supports two circumferentially spaced guide magnets  36  in guide towers  37 . The guide towers are preferably 180° apart, and the docking magnets are preferably in two groups, each separated by about 45°. Further facilitating pivoting motion of the follower arm  38  and outer housing hub  10  is the bearing  54 . 
         [0044]    Without the magnets  36 / 39  the follower arm  38  could spin around the axis A without significant restraint. With these magnets there is a tendency of the outer hub to seek either an alignment where the guide magnets  36  are aligned with docking magnets  39 A or alternatively an alignment where they are aligned with docking magnets  39 B. One of these positions corresponds to a dwell position where the filling valve is sealed on the bottle. Another corresponds to a dwell position where the filling valve is not sealed on the bottle. 
         [0045]    Because magnetic force facilitates the dwell positions, there is less need for springs that facilitate dwell positions or hold ceramic seals in abutment. This reduces maintenance issues, and reduces leakage between spring replacement. 
         [0046]    An inside wall  57  of the stationary housing  55  helps define an internal bore. Within and adjacent the bore are positioned a variety of parts including the fork shaft  28 , bushings  20 ,  22  and  24 , an inner housing hub  14  linked via a transverse pin  48  to the fork shaft  28 , a thrust washer  34 , an outer barrier  12 , and retaining rings  50  and  52 . 
         [0047]    The risk of leakage adjacent the connection between the follower arm  38  and shaft  28  is reduced as the shaft can be essentially hermetically sealed from the follower arm, yet still be caused to rotate/pivot as desired. Further, the forked linkage  11 , and thus the valve assembly  6 , are enabled to dwell at desired positions without relying solely on spring pressure and the like to hold the positions. 
         [0048]    It should be appreciated that the principles of the present invention are not limited to the specific embodiment described herein. For example, any given filling machine will likely have fifty or more individual filling chambers, rather than just one. Further, the exact configuration of the filling chambers will vary based on what is being bottled. 
         [0049]    Moreover, the linkage to the valve assembly need not necessarily be in the form of a fork on stem connection. Numerous other types of connections for converting pivoting motion to axial motion are likely to also be suitable. 
         [0050]    Moreover, as shown in  FIG. 9 , the magnetic coupler can be formed by axially spaced arrays, rather than radially spaced arrays. 
         [0051]    Therefore, the invention should not be limited to the specific embodiment described and/or depicted herein. Rather, the claims should be looked to in order to judge the full scope of the invention. 
       INDUSTRIAL APPLICABILITY 
       [0052]    The invention provides improved valve actuator assemblies for use in automated container filler equipment, and such automated container filler equipment.