Abstract:
A container inspection apparatus and method measures both warp and off-level of an annular sealing surface of a container. The apparatus preferably has a warp gauge device and an off-level gauge device suspended over a container support and base by at least one column for the warp gauge device and a pillar for the off-level gauge device. When measuring for warp, the off-level gauge device is constructed and arranged to pivot clear of the warp gauge device, and vice-versa when measuring for off-level. The container preferably is held laterally or radially in place by two V-bracket assemblies, and vertically in place by a container support. The V-bracket assemblies are adjustable vertically to accommodate containers of differing diameters and heights. A spring loaded roller assembly supported by the pillar biases the sidewall of the container against the V-bracket assemblies assuring multiple points of contact properly to orient the container for distortion measurements by both the warp and off-level gauge devices. The V-bracket assemblies preferably are associated with a scale for orienting the containers of differing diameter along a common centerline utilized by both the warp and off-level gauge devices.

Description:
The present invention is directed to inspection of containers, and more particularly to an apparatus and method for measuring distortions at the sealing surface of a container finish. 
   BACKGROUND OF THE INVENTION 
   In the manufacture of containers, such as glass or plastic bottles and jars, the container typically is formed with a finish having an axis and one or more external threads or beads for securing a closure to the finish. The finish has an open mouth surrounded by an axially facing sealing surface for sealing engagement with a closure applied to the container. Manufacturing anomalies can occur at the container sealing surface, such as a warp or an off-level condition, also known as a cocked sealing surface. A “warp” at the sealing surface generally refers to departure of the sealing surface from a planar configuration. “Off-level” refers to a tilt of the average plane of the sealing surface from an orientation perpendicular to the container axis. Warp and off-level anomalies at the sealing surface can occur in combinations, and can affect the ability of an automatic capping machine to apply a closure to the finish and/or to the ability of the closure to form an effective seal against the sealing surface. 
   SUMMARY OF THE INVENTION 
   A container inspection apparatus and method measures both warp and off-level of an annular sealing surface of a container. Preferably, the apparatus has a warp gauge device and an off-level gauge device suspended over a container support and base, preferably by means of two parallel columns for the warp gauge device and a pillar for the off-level gauge device. When measuring for warp, the off-level gauge device is constructed and arranged to pivot clear of the warp gauge device, and vice-versa when measuring for off-level. 
   The container is held laterally or radially in place preferable by two vertically spaced V-bracket assemblies, and is held vertically in place by a container support. Each V-bracket assembly is supported by, and adjusts vertically along the pair of, columns to accommodate containers of varying heights. A spring loaded roller assembly supported by the pillar biases the sidewall of the container against the V-bracket assemblies assuring multiple points of contact against the container sidewalls properly to orient the container for warp and off-level distortion measurements by both the warp and off-level gauge devices. 
   Each bracket assembly has a V-block that adjusts generally horizontally to accommodate containers of varying diameters. A pair of guide rods preferably project rearward from the V-block and through a bridging member that slides directly along the columns. Similarly, the V-bracket assembly has a scaled bar with indicia, which projects rearward from the V-block and through the bridging member. The indicia correspond to varying diameters of container sidewalls permitting pre-alignment of the V-bracket assemblies to containers having known diameters at two contact levels. Once aligned, the container is properly positioned for both warp and off-level measurements simplifying the inspection process and providing accuracy in establishing the degree of distortion in one robust and relatively compact apparatus. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiment of the present invention is disclosed in the following description and in the accompanied drawings, wherein: 
       FIG. 1  is a side view of a container sealing surface inspection apparatus of the present invention; 
       FIG. 2  is a perspective view of the container sealing surface inspection apparatus illustrating engagement of an off-level gauge device to a container; 
       FIG. 3  is a perspective view of the container sealing surface inspection apparatus illustrating engagement of a warp gauge device; 
       FIG. 4  is a partial perspective view of the container sealing surface inspection apparatus illustrating engagement of a bracket assembly engaged to a side wall of the container; 
       FIG. 5  is a perspective bottom view of a support plate of the warp gage device; 
       FIG. 6  is a partial perspective view of the container sealing surface inspection apparatus illustrating a V-block scale of the bracket assembly; 
       FIG. 7  is a partial perspective view of the container sealing surface inspection apparatus illustrating a container support; 
       FIG. 8  is a partial perspective view of the container sealing surface inspection apparatus illustrating a second embodiment of a container support; and 
       FIG. 9  is a top view of the V-block scale of the bracket assembly. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A container sealing surface inspection apparatus  20  of the present invention, through a warp gauge device  22  and an off-level gauge device  24 , measures distortion of a substantially annular sealing surface  26  ( FIGS. 2 and 6 ) of a glass container  28 . As illustrated in  FIG. 1 , the devices  22 ,  24  are manual devices in which dial indicators or read-out gauges  30 ,  32  are brought into engagement with the container sealing surface  26  and the indicators are observed while the container  28  is rotated by hand. 
   Referring to  FIG. 5 , a warp is a distortion or departure of the sealing surface  26  from being at a planar configuration. For instance, a saddle warp will have two lows and two highs corresponding to two cycles in the finish. During warp measurement, a plane generally will be defined by three orthogonally spaced points, a first point  34  at zero degrees around the sealing surface, a second point  36  at one-hundred eighty degrees, and a third point  38  at ninety degrees. The measurement will then be the deviation from this plane of the fourth point  40  at two-hundred seventy degrees. 
   This four-point system removes other factors such as off-level and container movement from the result, which will be discussed later in further detail. The manual measurement gauge for warp uses two solid rods or pins  42 ,  44  which form an elongated crest or inverted rib  47  for contacting the three circumferentially fixed points  34 ,  36 ,  38 . The warp gauge device  24  measures the deviation in the fourth point  40  as illustrated in FIGS.  1  and  3 - 5 . The device can be calibrated to zero by placing a calibration plane against the three reference points and the measurement point, and setting dial indicator  30  to zero. The deviation of the plane for a finish with a warp would then be the maximum positive (or negative) deviation from zero. An alternate method eliminates the need for this calibration. The warp measurement would be equal to one-half of the sum of the maximum and minimum readings. The container only needs to be rotated a minimum of 180° for warp (or dip) measurement. A maximum and minimum will be found in any 180°. This simplifies the hand measurement. Rotation at 360° is still required for the off-level measurement. This device will also measure the deviation from a plane for a finish with a dip. A dip is similar to warp but confined to a limited angular area of the sealing surface. The warp gauge device  22  is integrated into a support base  46 , also utilized by the off-level gauge device. 
   The first and second pins  42 ,  44  of the warp gauge device  22  are mounted on, or seated into, a bottom side  50  of a support plate or disc  52  for engaging the container sealing surface  26  at the three orthogonally spaced points  34 ,  36 ,  38 . The dial indicator  30  of the warp gauge device  22  mounts on the support plate  52  so that an indicator stem  54  of dial indicator  30  extends axially through the disc  52  to engage the container sealing surface  26  located below at the fourth point  40 . As illustrated in  FIG. 5 , the first pin  42  is generally twice as long as the second pin  44  and extends through a center point  56  of the disc  52  which co-aligns to a center axis  58  of the container  28 . Thus, the first two points  34 ,  36  located on the first pin  42  are diametrically opposed to one another. The third point  38  is located along the second pin  44  which extends generally radially outward from the center point  56  so that the third position  38  is spaced approximately ninety degrees from the first and second points  34 ,  36 . Generally diametrically opposed to the second pin  44  is a slot  60  carried by the disc  52  which communicates axially through the disc  52  and extends radially outward from the center point  56 . 
   The indicator stem  54  of the dial indicator  30  projects downward through the slot  60  to engage the sealing surface  26  of the container  28  at the fourth point  40 . In order to adapt to container sealing surfaces  26  having varying diameters, the indicator stem  54  and dial indicator  30  are moveable along the slot  60 , thus capable of adjusting radially with respect to the container  28 . A rod parallel to slot  60  attached perpendicular to indicator stem  54  could eliminate or reduce the adjustment of indicator stem  54  and dial indicator  30  along slot  60 . 
   Once the dial indicator  30  of the warp gauge device  22  is adjusted radially within the slot  60  with respect to the container  28 , a block  62  that supports the dial indicator  30  and slides along a top side  63  of the disk  52  is secured rigidly to the disc  52  by at least one fastener or screw (not shown) which rides within its own slot carried by the block  62 . With the container  28  held in position, the container is rotated and the indicator stem  54  along with the remaining three orthogonally spaced points  34 ,  36 ,  38  realign with respect to the sealing surface  26  thus measuring the amount of warp of the sealing surface  26  along the entire three-hundred sixty degrees. 
   Referring to  FIGS. 1-3  and  6 - 8 , the off-level gauge device  24  measures for an off-level condition which refers to a tilt of the average plane of the sealing surface  26  from an orientation generally perpendicular to the container axis  58 . The measurement of this plane tilt or off-level is the deviation between a reference point  64  and a probe point  66  that are spaced one-hundred eighty degrees apart around the sealing surface  26 . True warps at the sealing surface  26  typically are not detected during the off-level measurement because the high and the lows of a saddle warp are generally the same but one-hundred eighty degrees apart. An off-level condition of the sealing surface  26  can be measured with respect to a container sidewall  68  or a container bottom depending upon the set-up of the container sealing surface inspection apparatus  20 . 
   For off-level measurements with respect to the container sidewall  68 , the off-level gauge device  24  has two bracket assemblies  70 ,  71  which engage the sidewall  68  at two vertically spaced positions. As best illustrated in  FIG. 7 , the container  28  is held vertically by a point contact or domed apex  72  at the bottom of the container  28  substantially near the center axis  58 . A spring loaded roller assembly  74  is diametrically opposed to and centered substantially axially between the two bracket assemblies  70 ,  71  for holding the container  28  against a pre-aligned V-block  76  of each bracket assembly  70 ,  71 . Because the container  28  is supported by the domed apex  72 , it is not restricted from tilting due to the bias of the spring loaded roller assembly  74 , which creates a four point contact of the sidewall  68  against the two V-blocks  76 . 
   The dial indicator  32  of the off-level gauge device  24  mounts on a support head  78  that carries a first rod  80  similar to the warp gauge device  22  for providing the reference contact point  64  at the sealing surface  26 . A second rod or cylindrical shaped member  82  is concentric to the first rod  80 , which generally intersects the center axis  58  of the container  28 . The second rod  82  is attached to the distal end of a downwardly projecting indicator stem  84  of the indicator, thus providing the probe contact  66  at the sealing surface. The second rod  82  is positioned such that its curved surface easily slides along the sealing surface  26  of the container  28  reducing possible snagging during manual rotation of the container  28 . As the container  28  rotates three-hundred sixty degrees, during which the four contacts at the V-blocks are continuously maintained, the off-level measurement is read by observing the dial indicator  32 . The continuously maintained contacts of the four points is what provides the side reference. 
   Referring to  FIGS. 4 and 8 , for off-level measurement with respect to the container bottom of the container  28 , the domed apex  72  and the roller assembly  74  are removed so that the container bottom surface rests squarely upon a planar container support  84  and the sidewall  68  of the container  28  is in contact with one V-block  76  at two contacts, instead of two V-blocks  76  amounting to four contacts. 
   More specific to the present invention, the warp and off-level gauge devices  22 ,  24  are supported by the common support base  46  which carries the container support and/or domed apex  72 ,  84 . A pair of parallel columns  86 ,  88  projecting upward from the support base  46  adjustably support the warp gauge device  22  and the pair of bracket assemblies  70 ,  71  oriented below the warp gauge device  22 . A pillar  90  projecting upward from the support base  46  adjustably supports the off-level gauge device  24  and the roller assembly  74  oriented below the off-level gauge device  24 . When measurement of warp is desired, the off-level gauge device  24  is cleared from the sealing surface  26  by being generally pivoted upward, and the warp gauge device  22  is lowered upon the sealing surface  26  along the columns  86 ,  88 . For off-level measurements, the warp gauge device  22  is slid upward along the columns  86 ,  88  enabling the off-level gauge device  24  to be pivoted downward upon the sealing surface  26 . 
   When measuring for warp and side-reference off-level, the bracket assemblies  70 ,  71 , the domed apex  72  and the spring-loaded roller assembly  74  are utilized and must be pre-aligned with respect to container height to achieve maximum spacing between the bracket assemblies  70 ,  71  and vertical centering of the roller assembly  74  between the bracket assemblies  70 ,  71  to optimize the four point contact of the V-blocks  76 . To accomplish this, each bracket assembly  70 ,  71  has a substantially horizontal bridging member  92  which carries vertical communicating bores which receive the respective columns  86 ,  88  for sliding the bracket assemblies  70 ,  71  vertically while eliminating any horizontal or lateral movement. When the desired vertical placement is achieved, the bracket assemblies  70 ,  71  are locked to the columns  86 ,  88  by tightening of respective locking levers  94 , which are threaded to the bridging member  92  adjacent each column  86 ,  88 . 
   Each bridging member  92  also carries a horizontal bore at each end for slideably receiving respective parallel guide bars  96 ,  98  of the bracket assembly  70 ,  71  that project rearward from the V-block  76 , and opposite angulated edges  100  of the V-block  76  which directly engage the sidewall or finish  68  of the container  28 . The guide bars  96 ,  98  assure that the V-blocks  76  adjust along consistent parallel planes. This adjustment is measured by a V-block scale  102 , as best illustrated in  FIG. 9 , which is a bar having indices  104  and projecting rearward from the V-block  76  and through the bridging member  92 . The bridging member  92  carries a viewing window  106  having an index point or line for reading the horizontal movement of the bracket assembly  70 ,  71 , which corresponds to the container sidewall diameter. Once the desired horizontal placement is achieved, the bridging member  92  is locked to the guide bars  96 ,  98  by tightening of respective locking screws  108  which are threaded to the bridging member  92  adjacent each guide bar  96 ,  98 . 
   With the bracket assemblies  70 ,  71  adjusted to the height and diameter of the container  28 , a sliding block  110  of the roller assembly  74  that receives the pillar  90  is slid vertically along the pillar  90  until a roller  112  of the assembly  74 , which directly engages the sidewall  68 , is oriented vertically between the two bracket assemblies  70 ,  71 . When so oriented, a lock down lever  114  threaded to the block  110  and adjacent to the pillar  90  is tightened to lock the roller assembly  74  vertically to the pillar  90 . The roller assembly  74  also includes a cantilevered structure  116  projecting horizontally from the slide block  110  within a sleeve  118  to a distal end  120 , which rotationally attaches to the roller  112  having a vertical rotational axis  121  so that the container  28  is easily rotated about its center axis  58 . A coiled spring  122  compresses between the distal end  120  of the cantilevered structure  116  and the sleeve  118  to comply with differing container diameters while biasing the container  28  horizontally against the V-blocks  76 . 
   Similar to the bracket assemblies  70 ,  71 , the warp gauge device  22  has a bridging portion  124  that receives both columns  86 ,  88 . An arm  126  of the warp gauge device projects laterally outward from the bridging portion  124  and attaches to the disc  52  through a plunger type clamp  128  and a series of springs  130  that generally bias the disc  52  against the sealing surface  26 . The springs  130  allow limited vertical movement and tilting of the disk  52  due to container warp or distortion while maintaining continuous contact between the four orthogonally spaced contact points  34 ,  36 ,  38 ,  40  and the sealing surface  26  while the container  28  is manually rotated at least 180°. The attachment to the disk  52  through the springs is made at a point that is offset from the center of the disk to ensure the head stays in contact with the sealing surface. This attachment point preferably is within a triangle formed by where the three fixed points contact the sealing surface of the container. Lockdown levers  132  (as illustrated in  FIG. 1 ) are threaded to the bridging portion  124  adjacent each column  86 ,  88  vertically to secure the warp gauge device  22  either against the sealing surface  26  of a test container or well above the container  28  and out of the way of the off-level gauge device  24 . 
   The off-level gauge device  24  is coupled to the pillar  90  by a support block  134 , which carries a vertically extending bore having a non-cylindrical profile that substantially corresponds to the cross-sectional profile of the flat sided pillar  90 . This non-cylindrical relationship prevents the off-level gauge device  24  from rotating around the pillar  90  and permits only a vertical adjustment of the device  24  to correspond with differing container heights. A leg  136  of the off-level gauge device  24  engages rotatably to the support block  134  at one end and supports the head  78  at a distal end above the container  28  during off-level measurements. As the leg  136  rotates with respect to the support block  134 , the head  78  pivots with the dial indicator  32  toward or away from the container  28 . A lockdown lever  138  is threaded to the support block  134  adjacent the pillar  90  vertically to secure the off-level gauge device  24  to the pillar  90 . A spring loaded plunger  140  is attached to the leg  136  to prevent further pivoting action. 
   While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not limited herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive rather than limiting and that various changes may be made without departing from the spirit or scope of the invention.