Abstract:
An apparatus and method for inspecting a container having a mouth, and a base with a punt opposite of the container mouth. Light energy is directed into the container and through the container mouth, using at least one light source, and light energy transmitted through the container mouth is sensed. The at least one light source is disposed on at least one side of the container so that the light energy is directed through a side wall of the container and onto the punt of the container base such that at least a portion of the light energy is reflected off the punt to extend through the container mouth to the light sensor.

Description:
The present disclosure is directed to methods and apparatus for optical inspection of containers. 
     BACKGROUND AND SUMMARY OF THE DISCLOSURE 
     In the manufacture of containers, various anomalies or variations can occur that affect the commercial acceptability of the containers. These anomalies, termed “commercial variations,” can involve numerous attributes of the container. For example, commercial variations can include dimensional characteristics of an open mouth of the container. Thus, it is oftentimes useful to provide inspection equipment capable of inspecting the containers for commercial variations. The term “inspection” is used in its broadest sense to encompass any optical, electro-optical, mechanical or electrical observation or engagement with a container to measure or determine a potentially variable characteristic, including but not necessarily limited to commercial variations. 
     Apparatuses for inspecting parameters of a container mouth are used in one type of inspection process for a container. Such an apparatus includes a light source that directs light energy into the container, and a light sensor disposed with respect to the light source and the container to receive light energy transmitted out of the container through the container mouth. A telecentric lens directs onto the light sensor only light energy transmitted through the container mouth substantially axially of the container mouth. The sensor develops a two-dimensional image of the container mouth, and is coupled to image processing electronics for determining or calculating a circle of greatest diameter that will fit within the two-dimensional image of the container mouth, and treating such circle as indicative of the effective inside diameter of the container mouth. An apparatus of this type is illustrated by U.S. Pat. No. 5,461,228, which is assigned to the assignee hereof and is incorporated herein by reference. 
     A general object of the present disclosure, in accordance with one aspect of the disclosure, is to provide an optical plug gage (OPG) apparatus effective for improving inspection of a mouth of a container having a punt in a bottom of the container. 
     The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other. 
     An apparatus for inspecting a container having a mouth, and a base with a punt opposite the container mouth, in accordance with one aspect of the disclosure includes at least one light source for directing light energy into the container, and out of the container through the container mouth, and a light sensor disposed with respect to the at least one light source and the container to receive light energy transmitted through the container mouth. The at least one light source is disposed on at least one side of the container so that the light energy is directed through a side wall of the container and onto the punt of the container base such that at least a portion of the light energy is reflected off the punt to extend through the container mouth to the light sensor. 
     In accordance with another aspect of the disclosure, there is provided a method of inspecting a container having a mouth, and a base with a punt opposite the container mouth, including the steps of directing light energy into the container, and out of the container through the container mouth, using at least one light source, and sensing light energy transmitted through the container mouth. The at least one light source is disposed on at least one side of the container so that the light energy is directed through a side wall of the container and onto the punt of the container base such that at least a portion of the light energy is reflected off the punt to extend through the container mouth to the light sensor. 
     In accordance with a further aspect of the disclosure, there is provided a method of inspection, including the steps of providing a container having a mouth and a base with a punt opposite the container mouth, and directing light energy into the container, and out of the container through the container mouth, using at least one light source. The method also includes the step of sensing light energy transmitted through the container mouth, wherein the at least one light source is disposed on at least one side of the container so that the light energy is directed through a side wall of the container and onto the punt of the container base such that at least a portion of the light energy is reflected off the punt to extend through the container mouth to the light sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure, together with additional objects, features, advantages and aspects thereof, will be best understood from the following description, the appended claims and the accompanying drawings, in which: 
         FIG. 1  is a schematic diagram of an optical plug gage apparatus for evaluating a mouth of a container in accordance with an exemplary embodiment of the present disclosure, and including a light source; 
         FIG. 2  is an enlarged fragmentary view of a portion of the apparatus and container of  FIG. 1 ; and 
         FIG. 3  is a schematic top view of a portion of the apparatus of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  illustrates an exemplary embodiment of an optical plug gage apparatus  10  for inspecting an inside surface S of an open mouth M of a container C. The apparatus  10  includes one or more light sources  12  disposed adjacent the container C on sides thereof to produce light used in inspecting the container mouth M, and one or more light sensors  14  disposed above the container C to sense light produced by the light source  12  and passing through the container mouth M. The apparatus  10  further may include a lens system  18  disposed between the container C and the light sensor  14  to direct light passing through the container mouth M to the light sensor  14 . The apparatus  10  additionally may include a processor  20  to scan the light sensor  14  and develop an image of the container mouth M and/or any other suitable inspection information, and a display  22  to display the image and/or other inspection information. The apparatus  10  also may include a container rotator  24  to rotate the container C. As shown in  FIG. 3 , a material handling mechanism  16  may be constructed and arranged to move the container C. 
     The container C may be ajar, or a bottle as illustrated in  FIG. 1 , or any other suitable type of container that includes a base B having a punt P that may be disposed axially opposite of the container mouth M. Bottles having a punt P are common for packaging wine. The punt P may have a height, extending from the bottom of the base B to the top of the punt P, that typically is about 20% to about 80% of the outside diameter of the container C. The container C may be composed of plastic, glass, or any other suitable material. The container C may be clear, colored, transparent, translucent, or of any other suitable optical quality. 
     As shown in  FIG. 3 , the material handling mechanism  16  may include opposed legs  16   a ,  16   b  between which the container C is disposed and moved by the mechanism  16  in any suitable manner. The mechanism  16  may be a star wheel or any other suitable container handling device, and its legs  16   a ,  16   b  may be disposed at any suitable elevation with respect to the container. 
     As also shown in  FIG. 3 , the light source  12  may include a plurality of discrete sources  12   a ,  12   b ,  12   c . For example, the light source  12  may include one side source  12   a  on one side of the container C, and two other side sources  12   b ,  12   c  disposed adjacent to each on another side of the container C generally opposite that of the one side source  12   a . An imaginary line L bisects the container C into two sides. The one side source  12   a  may be disposed between the opposed legs  16   a ,  16   b  of the material handling mechanism  16 . The other side sources  12   b ,  12   c  may be disposed beneath the container rotator  24 , between the rotator  24  and the container base B ( FIG. 1 ). Accordingly, the side sources  12   a ,  12   b ,  12   c  may be sized and arranged about the circumference of the container C to each illuminate a portion, for example about twenty to forty angular degrees, of the circumference of the punt P. Accordingly, the container C may be rotated by the rotator  24  to provide full circumferential illumination, wherein several images of portions of the container mouth M may be obtained and superimposed or added to produce a composite image of the container mouth M. Those of ordinary skill in the art will recognize that more or less than the three side sources  12   a ,  12   b ,  12   c  may be used. 
     The light source  12  may include any suitable type of device, including a plurality of light emitting diodes (LEDs), incandescent bulbs, fluorescent bulbs, or any other suitable type of light source. In any case, those of ordinary skill in the art will recognize that the light source  12  may receive power from any suitable source in any suitable manner and may be communicated to and controlled by the processor  20  in any suitable manner. Moreover, those of ordinary skill in the art will recognize that the light source  12  may be composed of any suitable quantity of individual light sources instead of just the three sources  12   a ,  12   b ,  12   c.    
     Preferably, with respect to  FIG. 1 , the light source  12  is not disposed adjacent an upper half of the container C above a half-height line H bisecting the container C, or beneath the base B of the container C. Such positioning of the light source  12  was discovered to result in excessive absorption of light by the walls of the container C and/or refractions/reflections off interior surfaces of the container C. Such excessive absorption and/or refractions/reflections can result in false, inconclusive, or otherwise unreliable inspection results. 
     Instead, it was discovered, that the light source  12  may be disposed adjacent to the base B of the container C, and adjacent a bottom half of the container C below the half-height line H. More particularly, the light source  12  may be generally positioned in correspondence to, the punt P of the container C as shown in  FIGS. 1 and 2 . For example, the light source  12  may be axially centered on and/or axially overlapping with respect to the punt P. Accordingly, the light source  12  is constructed and arranged to target or selectively illuminate the punt P. Also, the light source  12  may be oriented in a generally transverse direction with respect to the longitudinal axis A of the container C as shown in  FIGS. 1 and 2 . More particularly, the source  12  may be oriented substantially perpendicularly with respect to the container axis A. As used herein, the term “substantially” means within typical glass container manufacturing and equipment setup tolerances. One or more of the above light source positions and/or orientations are believed to reduce or eliminate the excessive absorption and/or refractions/reflections to result in more reliable inspection results. 
     Still referring to  FIG. 1 , the light sensor  14  may include any suitable device to sense light. For example, the light sensor  14  may include an image sensor, for instance, a charge-coupled device (CCD), complementary metal-oxide-semiconductor (CMOS) device, or any other suitable image sensor. In another example, the light sensor  14  may include a photodiode device, a photoresistor device, or any other suitable photodetector device. 
     The lens system  18  may include any suitable device to direct or focus light. For example, the lens system  18  may include a telecentric lens, an entrance pupil, and pupil lenses on either side of the pupil. The lens system  18  may direct only light rays that emerge from the container mouth M essentially parallel to an axis A of the container C. 
     The processor  20  may include any suitable device(s) to acquire images from the light sensor  14  and output images to the display  22 . 
     The container rotator  24  may include any suitable device to rotate the container C. For example, the rotator  24  may include one or more rollers, wheels, belts, discs, and/or any other suitable element(s) to rotate the container C. In another embodiment, the container C may remain stationary, and one or more of the various apparatus elements  12 ,  14 ,  16 ,  18  may be rotated in any suitable manner. 
     Referring now to  FIG. 3 , and with regard to the material handling mechanism  16  and container rotator  24 , an example of an indexing and inspection machine that may utilize the optical inspection apparatus and method of the present disclosure is shown in U.S. Pat. No. 6,581,751, which is incorporated herein by reference. The machine disclosed in that patent receives a continuous stream of glass articles from an infeed conveyer and transports the articles through a series of angularly spaced inspection stations, each of which examines the container according to different criteria. The indexing and inspection machine includes a first array of gripping fingers mounted on a lower carrier, and a second array of gripping fingers mounted on an upper carrier. Rotation of the carriers with respect to each other causes the finger arrays to grip and release the glassware articles between the individual fingers, while rotation of the carriers conjointly causes them to index the glassware between inspection stations. At least some of the inspection stations include drive rollers for rotating a container about its axis for inspection or other purposes. 
     Another example of an indexing and inspection machine that could utilize the optical inspection apparatus and method of the present invention is disclosed in U.S. Pat. No. 3,313,409, which is incorporated herein by reference. The apparatus disclosed in that patent uses a belt conveyer to transport containers along a guideway. In general operation, the containers encounter an indexing head that is circular and has a plurality of circumferentially spaced pockets for receiving the containers. The indexing head is successively indexed to bring each container into position in adjacent inspection stations, which may inspect the containers for various commercial variations and/or other characteristics. After the container has been inspected by each inspection station, the container encounters a discharge station which ejects it onto a conveyer for carrying the container away from the machine. Of course, the above-mentioned patents disclose only two examples of machines that may employ the optical inspection apparatus and method of the present invention, as numerous other machines also exist. 
     In one example of operation of the presently disclosed apparatus  10 , the light source  12  is energized, and at least some of the light from the side sources  12   a ,  12   b ,  12   c  travels through an outer wall W of the container C, into the container C, and reflects off the punt P extending parallel to the container axis A and through the container mouth M. More particularly, the light reflects off a surface of the punt P disposed within an interior I ( FIG. 1 ) of the container C. The light traveling through the container mouth M is sensed by the light sensor  14  to obtain a corresponding image of the container mouth M. 
     There thus has been disclosed an apparatus and method for optical inspection of a container, that fully satisfies all of the objects and aims previously set forth. The disclosure has been presented in conjunction with several exemplary embodiments, and additional modifications and variations have been discussed. Other modifications and variations readily will suggest themselves to persons of ordinary skill in the art in view of the foregoing discussion. The disclosure is intended to embrace all such modifications and variations as fall within the spirit and broad scope of the appended claims.