Patent Publication Number: US-6662928-B2

Title: Apparatus and process for handling circular articles

Description:
REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 09/589,709, now issued as U.S. Pat. No. 6,547,057. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to automated apparatus for handling like circular articles, such as discs, rings, and lids, for example. More particularly, the present invention is directed to such an apparatus that is capable of receiving a multiplicity of such articles in a known or unknown orientation and processing them into a counted stack of articles, all having the same known orientation, ready for further manual or automated handling. 
     In order to remain competitive, many companies seek to simplify various aspects of their manufacturing processes through automation. This is particularly true of companies involved in bulk manufacturing, such as injection molding and printing, in which each step of a process may yield a number of circular articles that are generally flat in cross section. Often, the rate at which such articles can be produced is limited only by how fast they can be removed, collected or dispersed. In view of this challenge, automators have concentrated on fewer, more reliable process steps. 
     Previous automated processes for orienting articles such as lids have employed various techniques with differing degrees of success. The early prior art for handling lids or other articles used a simple accept/reject technique, in which improperly oriented articles were returned to a holding area proximate the input of the handling apparatus in the hope that the improperly oriented articles would become correctly oriented as the result of being randomly disturbed and processed again. In a high speed production process, this technique impedes the throughput and adds unecessary process steps. 
     Another prior art orientation technique employs a constant airflow sufficient to reorient incorrectly oriented articles, while not disturbing the correctly oriented articles. Obviously, the strength of an indiscriminate airflow is very important to ensure that only incorrectly oriented articles are reoriented. This process is also undesirable in the case of some flat articles that may be susceptible to being reoriented, regardless of whether they are properly or improperly initially oriented. 
     The more recent prior art processes involve more active control of the orientation of flat articles through the controlled use of airflow to orient the article based on a signal from a sensor capable of determining the present orientation of the article. These prior art systems are deficient in that they lack mechanical interaction with the flat article. By relying on the timing of a burst of air, these systems struggle to achieve the orientation accuracy required for later automation at the rates of current manufacturing and printing processes. 
     Prior attempts to create counted collections of generally flat articles have also proven to be inadequate. One such prior art technique involves the use of two horizontal bars positioned for rotation in the same direction to thereby impart a rotational force on the peripheral edge of the article so as to provide a stabilizing gyroscopic effect permitting the collection and maintenance of a rotating horizontal stack of the articles. The challenge associated with this technique is one of repositioning articles that are supplied in a generally horizontal position into a vertical position, taking into account the difference between the rotational speed of the article and that of the rotating bars. Prior art methods for repositioning flat articles from a horizontal position to a vertical position have either involved excessive floor space or complex mechanisms. Also, the physical and kinematic differences in the rotational speeds of the flat article relative to the rotating bars can result in erratic behavior of the article and lost production. 
     The foregoing deficiencies of prior art flat article orientation and collection techniques have prevented the successful counting of those articles, and have left the user to estimate the number of such articles in a stack, based upon the measured length of the stack. The impediments to accurate counting of collected flat articles are variations in their thickness, the inability to consistently closely pack the articles, and the invasive nature of apparatuses for separating a rotating collection thereof at the required length. These factors directly affect the length of a stack containing the required number of articles and frustrate automated or manual packing techniques for quickly determining the required number of articles, based upon a static measurement of stack length. Nevertheless, automated attempts at counting the number of flat articles in a stack are known in the prior art. One such apparatus involves the application of a lateral force along the length of the required number of articles to thereby separate them from articles that are subsequently collected. Another prior art counting apparatus attempts to insert a thin wheel into a seam between adjacent articles of a rotating stack thereof. Both of these prior art apparatuses cause disruption to the rotating stacks, oftentimes resulting in dropped articles that are lost to production. 
     Exemplary of prior art lid handling apparatus is that described in U.S. Pat. No. 3,682,292 to Drew. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an apparatus for receiving a multiplicity of like circular articles, such as discs, rings, and lids, for example, presented in a known or random horizontal orientation, and for collecting them into a horizontal counted stack in which each of the circular articles of the stack has the same on-edge or vertical orientation. In the embodiment of the invention in which the multiplicity of circular articles are presented in random horizontal orientation, some right side up and some upside down, they are sequentially conveyed to a pair of rotating spinner wheels that contact diametrically opposing points along the periphery of each of the circular articles to impart rotation thereto in a selected direction and, by means of a speed differential between the two spinner wheels, to propel each article into a rotating first article orientation tube. The direction of rotation of the rotating spinner wheels are a function of the initial sensed orientation, either right side up or upside down, of each of the circular articles. The combination of the downstream force imparted by the spinner wheels and the slight frictional engagement between the peripheral edge of each of the circular articles and the inner surface of the first article orientation tube serves to slow the speed at which each of the circular articles is spinning and to thereby reorient them into an on-edge or vertical position as they travel through the first orientation tube. An optional, shorter second article orientation tube is axially aligned with the first article orientation tube proximate the downstream end thereof and is rotationally driven in the same direction as that of the first article orientation tube and at a speed selected to promote discharge of the spinning, vertically-oriented circular articles from the downstream end thereof, where they are received in that position onto a pair of rotating spin bars. The rotating circular articles received on the pair of rotating spin bars are collected onto a counted horizontal stack of on-edge circular articles, at which time the stack is seperated from a subsequent collecting stack in preparation for manual or automatic removal from the rotating spin bars for further processing. 
     In a second embodiment of the present invention, one of the spinner wheels is eliminated, and the second article orientation tube is also eliminated. This configuration may be utilized in situations in which all of the circular articles are initially presented in a common horizontal orientation, either all right side up or all upside down. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial diagram illustrating an apparatus for handling like circular articles, in accordance with a first embodiment of the present 
     FIG. 2 is a front elevation view of the apparatus of FIG.  1 . 
     FIG. 3 is a detailed pictorial diagram illustrating a portion of the apparatus of FIGS. 1 and 2. 
     FIG. 4 is a detailed pictorial diagram illustrating a portion of an apparatus for handling like circular articles, in accordance with a second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIGS. 1-3, there is shown a lid handling apparatus  100  supported by frame members  10  and  12 . A conveyor belt  14  or other conventional means of conveyance is positioned to sequentially receive a multiplicity of circular articles  16  from a conventional external source. Circular articles  16  may be lids, discs, rings or any of a number of other such circular articles that are generally flat in cross section. A conveyor belt  14  is arranged for travel over a vacuum box  18  having a vacuum port  20  to which an external source of vacuum is coupled. Conveyor belt  14  includes a spaced plurality of longitudinally aligned vacuum openings  22  for contacting each of the articles  16  as they are received on conveyor belt  14  to insure that they are conveyed downstream at the speed of the conveyor belt  14 . A pair of guides  19 ,  21  along the edges of conveyor belt  14  serve to align the articles  16  as they are being conveyed downstream. An upper guide member  24 , fixedly mounted above conveyor belt  14 , serves to further confine the articles  16  during conveyance. 
     A pair of reversible spinner wheels  26 ,  28 , controlled by conventional motor control means, are positioned at the height of the conveyor belt  14  proximate the downstream end thereof to contact diametrically opposite points along the peripheral edge of the articles  16  as they exit the conveyor belt  14 , to thereby impart rotation in a selected direction thereto, and, by providing a speed differential between spinner wheels  26 ,  28 , to propel each article into a first article orientation tube  30  that is longitudinally aligned with conveyor belt  14 , but arranged to slope slightly downwardly away from the downstream end thereof. Spinner wheels  26 ,  28  preferably have concave surfaces for contacting the peripheral edge of articles  16 . An article position sensor  38  is mounted proximate the downstream end of the conveyor belt  14  to sense the presence of one of the articles  16  at that position. An article orientation sensor  36  is also mounted proximate the downstream end of the conveyor belt  14  to sense whether the one of articles  16  that is about to be contacted by the pair of spinner wheels  26 ,  28  is oriented right side up or upside down. If the articles  16  are flanged lids, for example, as illustrated in FIGS. 1-3, and the one of the articles  16  about to be contacted by the pair of spinner wheels  26 ,  28  is oriented flange up, also as illustrated in FIGS. 1-3, spinner wheels  26 ,  28  are preferably both driven to rotate counterclockwise, as viewed from above. If the article  16  is oriented flange down, as sensed by article orientation sensor  36 , then spinner wheels  26 ,  28  are preferably reversed such that both are driven to rotate in the clockwise direction. However, it is possible to rotate just one of spinner wheels  26 ,  28 , while the other is stopped. It is also possible to drive them in opposite directions of rotation. The important consideration is that the speed differential between spinner wheels  26 ,  28  be such as to propel each of articles  16  in the downstream or forward direction. 
     The force imparted to each of the articles  16  by spinner wheels  26 ,  28  serves to spin them into the article orientation tube  30 , as illustrated in FIG.  3 . Article orientation tube  30  is rotationally driven in the direction indicated in FIG. 3 by a driving roller  32  that engages a rib  34  on the outer surface of article orientation tube  30 . However, any other conventional method of rotationally driving article orientation tube  30  may be employed. The combination of the downstream force imparted by spinner wheels  26 ,  28  and the slight frictional engagement between the peripheral edge of each of the articles  16  and the inner surface of the article orientation tube  30  to thereby slow the speed at which each of the articles  16  is spinning serves to reorient them into an on-edge or vertical position as they travel through orientation tube  30 . The orientation of articles  16  within orientation tube  30 , either flange forward or flange backward, may be changed by reversing the direction of rotation of orientation tube  30  or by reversing both the direction of rotation of spinner wheels  26 ,  28  and the speed differential therebetween to change the initial direction of rotation of articles  16  imparted by spinner wheels  26 ,  28 . An optional, shorter second orientation tube  40  is axially aligned with orientation tube  30  proximate the downstream end thereof and is rotationally driven in the same direction as that of orientation tube  30  at a speed selected to promote discharge of the spinning, vertically-oriented articles  16  from the downstream end thereof, where they are received in that on-edge position onto a pair of rotating spin bars  42 ,  44 . Alternatively, on-edge articles  16  may be received by any of a number of conventional devices other than rotating spin bars. Orientation tube  40  is rotationally driven from either of the spin bars  42 ,  44  by way of engagement with a rib  46  on the outer surface thereof, or by any other conventional driving mechanism. The flow of articles through orientation tubes  30 ,  40  may be optimized by varying the clearance distance between the diameter of articles  16  and the inner diameter of orientation tubes  30 ,  40 , as well as by varying the coefficient of friction of the inner surface of those tubes. For example, the inner surface of orientation tube  30  may be partially or entirely coated with teflon, while the inner diameter of orientation tube  40  may be tapered by approximately 0.15 inches toward the downstream end thereof. The speed at which spin bars  42 ,  44  are driven is selected to be approximately the same as the rotational speed of the articles  16  as they exit orientation tube  40  to thereby provide a smooth transition of articles  16  onto spin bars  42 ,  44 . Article orientation tubes  30 ,  40  are maintained in contact with their drive mechanisms by means of a pair of idler arms  48 ,  50 , respectively. A pair of air jets  52 ,  54  receive compressed air from an external source and direct a flow of air in the downstream direction into a small gap between orientation tubes  30 ,  40  to promote the smooth flow of articles  16  through orientation tube  40 . 
     After exiting orientation tube  40 , articles  16  move-downstream along spin bars  42 ,  44  on edge to form A collected horizontal stack of articles  16  against a conventional stop  56  at the far end thereof. In order to further process a collected stack of articles  16  on spin bars  42 ,  44 , it is generally required that the number of articles  16  forming the collected stack be known. It is therefore necessary to count the number of articles  16  during collection of the stack and to provide some means of demarcation of a stack when a specified number of articles  16  have been collected. Accordingly, a counter photocell  58  or other conventional sensor is positioned along conveyor belt  14 , which along with external conventional counter circuitry, serves to count each passing one of the articles  16 . When a desired number of articles  16  has been counted, a counter stop  60 , positioned along conveyor belt  14 , is momentarily actuated to interrupt the flow of articles  16  entering conveyor belt  14 . This has the effect of providing a space between the last one of the articles  16  required to form a collected stack of articles  16  of known number and the first one of the articles  16  forming the subsequent stack of articles  16  to be collected. A stack divider  62  is positioned below spin bars  42 ,  44  on tracks that permit it to be horizontally moved between the position shown by solid lines and that shown in phantom in FIGS. 1 and 2. As a stack of articles  16  is being collected on spin bars  42 ,  44 , the stack divider  62  is in the position shown in phantom in FIGS. 1 and 2. When the required number of articles  16  has been collected, as indicated by the space between articles  16  introduced by counter stop  60 , a stack divider arm  64  is raised upwardly from stack divider  62  into the space between articles  16  created by counter stop  60 , and the stack divider is then moved downstream to its position illustrated by solid lines in FIGS. 1 and 2, thereby pushing the counted collected stack of articles  16  against the fixed stop  56  at the downstream end of spin bars  42 ,  44 . The counted collected stack of articles  16  is then manually or automatically removed from the spin bars  42 ,  44  for further conventional processing, the stack divider arm  64  is retracted, and the stack divider  62  is moved to the position shown in phantom in FIGS. 1 and 2, awaiting the space between articles  16  that signals completion of the subsequent counted collected stack of articles  16 . 
     While the speeds at which spinner wheels  26 ,  28  and orientation tubes  30 ,  40  rotate are matters of design choice to optimize performance of apparatus  100  when handling various types and sizes of articles  16 , certain parameters have been selected in the case of handling common flanged lids having a diameter of approximately 4{fraction (9/16)} inches. In that case, spinner wheel  26 , having a diameter of 1¾ inches, rotates at approximately 1600 feet/minute, and spinner wheel  28 , having the same diameter, rotates at approximately 778 feet/minute. Orientation tube  30 , having an inside diameter of approximately five inches, rotates at approximately 400 feet/minute, while orientation tube  40 , having the same diameter and separated from orientation tube  30  by a gap of approximately 0.100 inch, rotates at approximately 600 feet/minute. 
     Referring now to FIG. 4, there is shown a detailed view of a portion of a lid handling apparatus  200  constructed in accordance with an alternative embodiment of the present invention. The construction and operation of lid handling apparatus  200  is the same as described above in connection with lid handling apparatus  100  illustrated in FIGS. 1-3, except that it includes only one spinner wheel  210  and one article orientation tube  220  for handling articles  16 . This alternative apparatus may be employed to handle articles  16  which are initially presented in the same orientation, either all right side up or all upside down. In this case, the single spinner wheel  210 , rotating in the clockwise direction, urges each of the circular articles  16  against a guide member  80  that is fixedly positioned on the opposite side of conveyor belt  14  from spinner wheel  210 , to thereby impart rotation to each of the articles  16  and to propel them into the single orientation tube  220 . Alternatively, the positions of the single spinner wheel  210  and guide member  80  may be reversed. In that configuration, the direction of rotation of both spinner wheel  210  and that of orientation tube  220  would also be reversed. As stated hereinabove, the orientation of articles  16  by orientation tube  220  may be reversed by reversing the direction of rotation thereof.