Method and system for counting irregularly shaped moving articles
This is a continuation of co-pending application(s) Ser. No. 07/710,731 filed on Jun. 04, 1991, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a method and a system to count moving articles and, more particularly, to a method and a system for counting irregularly shaped articles being moved into a machine that performs printing, slotting and cutting operations on such articles to form finished boxes which are also counted as they are being moved out of the machine. 
     Methods and systems for counting moving articles are known and are described in U.S. Pat. Nos. 4,166,246 (Matt); 4,237,378 (Jones); 4,504,916 (Oka) 4,665,392 (Koontz) and 4,881,248 (Korechika). U.S. Pat. No. 4,166,246 discloses a counting system used in the packaging industry. 
     In the manufacturing process of packaging boxes, it is common to use an initial blank that has irregularly shaped portions such as flap regions as well as irregularly occurring spaced cutouts in the blanks. Machines using such blanks commonly have a counter/ejector assembly whose operation is dependent on accurate counting. For such assemblies, blank counting is commonly accomplished by a retro-reflective photocell that senses the presence of blanks. Accurate counting by such sensing is made difficult by the presence of dark, black or brown, printed images or cutouts in the blank that may be present in the optical path of the photocell. These images and cutouts cause the photocell to change states several times before the actual blank end, and thus create multiple counts for each blank which, in turn, may be misinterpreted by the counting means. 
     To combat this misinterpretation, the photocell may be physically moved to an area of the blank, which moves past the photocell, that does not have printing or cutouts. For certain type blanks used in the formation of certain style boxes, it is not always possible to provide such an area. Further, moving the photocell is time consuming and has attendant production losses that may be encountered each time different style boxes are to be formed. 
     It is an object of the present invention to provide a system that does not suffer the drawbacks of the prior art devices and which accurately counts moving articles, such as irregularly shaped blanks, and different style formed boxes. 
     It is a further object of the present invention to provide a method which accurately counts the articles in spite of the presence of various dark images as well as cutouts. 
     Still further, it is an object of the present invention to provide a machine having a counter/ejector assembly that accurately counts both initial irregularly shaped blanks and different style boxes that are formed by the machine. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a method and a system for counting articles that are being moved along a predefined path such as that which occurs in the manufacturing of packaging boxes. 
     The system comprises a microprocessor responsive to input signals generated by means for detecting leading and trailing edges of the articles being moved into a packaging machine, distance sensing means used to determine the length of the article being moved, and means for counting the formed containers or boxes leaving the packaging machine. The means for detecting the leading or trailing edge is located at the input stage of the machine and respectively generates start and stop event signals that are sent to the microprocessor. The distance sensing means counts incremental changes which are indicative of the movement of the articles into the machine and generates and sends signals representative thereof to the microprocessor. The means for counting is located at the output stage of the machine and generates and sends to the microprocessor an exit event signal for each counted container or box. The microprocessor accommodates a set-up or reference run for the machine and the actual production run of the machine. The microprocessor, in response to the first occurring start event, initiates the counting of the incremental changes from the distance sensing means and terminates the counting in response to the first occurring stop event. The cumulative count is decremented by one incremental change and serves as a set-up or reference length for each of the articles to be subsequently moved into the machine. The microprocessor, in response to the exit event, increments by one the number of containers being counted and then disables the monitoring of the exit event. The microprocessor then initiates the counting of the incremental changes from the distance sensing means and monitors such until the amount of such incremental changes corresponds to the reference length. The microprocessor then re-enables the monitoring of the exit event and the occurrence of such an exit event causes the count stored in the microprocessor of the number of containers being counted to be incremented. 
     The method of the present invention may be used for counting any moving article and comprises the steps of detecting the leading edge of a first reference article being moved into a machine, and then determining the length of this reference article by counting incremental changes of its movement. The method terminates such counting upon detecting the trailing edge of the reference article being moved into the machine. The cumulated count is then decremented by one incremental change and is then stored as the length of the reference article against which subsequent moving articles are compared. The method then detects the movement of the container or box, formed from the article, at the output stage of the machine, increments the count of the articles being counted, and then disables such counting. The microprocessor then counts the incremental changes from the distance measuring means until the accumulated amount is equal to the count of the reference article, whereby the counter storing the number of articles being counted is re-enabled. The method then waits for the container formed from the first subsequent article to move pass the detecting means in the output stage in the machine. The method continues the above steps, starting at the detection of formed boxes at the output stage, for subsequent articles that are being moved into the machine. 
     Other objects, advantages and novel features of the present invention will become apparent from the foregoing detailed description of the invention when considered in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown. 
     FIG. 1 is a functional representation showing the essential elements of the present invention. 
     FIG. 1A illustrates a typical box blank associated with the practice of the present invention. 
     FIG. 2 is a flow chart illustrating a step-by-step progression of one method of the present invention. 
     FIG. 3 is a side view of a machine for forming boxes or packages related to the present invention. 
     FIG. 4 is a top view of the box forming machine of FIG. 3. 
     FIG. 5 is a view taken along line 5--5 of FIG. 4, showing the detecting means located at the input stage of the machine. 
     FIG. 6 is a view, taken along line 6--6 of FIG. 5, showing further details of the means for detecting the moving article. 
     FIG. 7 is a view, taken along line 7--7 of FIG. 4, showing the distance sensing means related to the present invention. 
     FIG. 8 is a view, taken along line 8--8 of FIG. 7, showing further details of a distance sensing means. 
     FIG. 9 is a view, taken along line 9--9 of FIG. 4, showing the counting means located at the output stage of the machine. 
     FIG. 10 is a view, taken along line 10--10 of FIG. 9, showing the orientation of the counting means at the output stage of the machine. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to a method and a system to accurately count articles that are being moved into and out of a machine. FIG. 1 is a functional representation showing the essential elements of a system 10 of the present invention. The system 10 has various applications, but is particularly suited for counting articles that are being moved along a predetermined path during a manufacturing process such as occurs during the formation of containers or boxes. FIG. 1 shows irregularly shaped blanks 12A having cutouts being moved along a path 14 and being formed into packages o boxes 12B by a machine 16. The layout of a typical printed die cut box blank 12A is shown in FIG. 1A illustrating the printing and die cutting that may cause false counts such as discussed in the &#34;Background&#34; section. The system 10 of FIG. 1 that eliminates such false counts comprises a programmable controller such as a microprocessor 18, detecting means 20, distance sensing means 22, and counting means 24. 
     The microprocessor 18 stores information, has an internal clock, and is responsive to signals present at its inputs 26, 28 and 30 that are respectively generated by the means 20, 22 and 24. 
     The detecting means 20 is located at the input stage of the machine 16 and detects the leading and the trailing edges of each of the blanks 12A being moved into the machine 16. The means 20, in response to the detection of the leading and trailing edges of the blanks, respectively, generates start 20A and stop 20B event signals that are routed to the microprocessor 18 by way of input path 26. 
     The distance sensing means 22 provides information for the microprocessor 18 to determine the length of each of the blanks 12A being moved into the machine 16. The distance sensing means counts incremental changes representative of the movement of the blanks within the machine 16, and generates, in response thereto, electrical signals 22A which are representative of the movement of the blanks. This information is routed to the microprocessor 18 by way of path 28. 
     The counting means 24 is located at the output stage of the machine 16. The counting means 24 detects the articles 12B, commonly in the form of boxes that have been produced from the initial blanks 12A, being moved out of the machine 16 and generates an exit event signal to the microprocessor 18 by way of input 30. 
     The microprocessor 18, in response to the first occurring start event, generated by the detecting means 20, initiates the counting of the incremental changes from the distance means 22, and terminates such counting in response to the first occurring stop event of counter 24. The cumulated count is then decremented by one incremental change 22A to ensure, as to be described hereinafter, the proper operation of counter 24. The decremented count serves as a reference length against which each of the subsequent blanks being moved is compared. The microprocessor, in response to first exit event, increments by one the number of boxes being counted and then disables the monitoring of the exit event. The microprocessor then initiates the counting of the incremental changes from the distance sensing means 22. The counting continues until the amount of incremental changes corresponds to the reference length, whereupon the microprocessor then enables the monitoring of the exit event and the occurrence of such an exit event increments the count of the boxes being counted. If desired, the microprocessor 18 may be programmed to ignore the first occurring exit event from the counter 24 so that the box formed from the reference blank is not included in the number of containers being counted. 
     The operation of the microprocessor 18 for one embodiment of the present invention related to counting packaging boxes may be further described with reference to FIG. 2. FIG. 2 is a flow chart showing a step-by-step progression of the operation of the microprocessor 18 and comprises processing segments and decision segments, respectively, given in Tables 1 and 2. 
     
                       TABLE 1
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Processing Segments
                Nomenclature
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32              Determine number of pulses for
                the length of the new blank
                being used for the box.
34              Subtract one from total number
                of pulses and save the new
                value.
36              Add one to the box count and
                disable the counter.
38              Count pulses to determine end
                of blank.
40              Re-enable the box counter and
                wait for the box to pass.
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                       TABLE 2
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Decision Segments
                Nomenclature
______________________________________
42              New box style or normal run.
44              Box count photoeye detecting a
                blank.
46              Current pulse count = saved
                pulse count.
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     The step-by-step progression shown in the flow chart of FIG. 2 may be divided into a setup run and a normal run, wherein the setup run comprises decision segment 42 and processing segments 32 and 34, whereas the normal run comprises the rest of the decision and processing segments shown in FIG. 2. 
     In practice, the setup run is used to establish a reference for counting the finished boxes that are to be produced by the machine 16 for each new order or style of box. This reference length is necessary because each new style box may be of a distinct length. For such a setup run, the detector means 20, shown in FIG. 1, detects the leading edge of the reference blank 12A being moved into the machine and generates the start signal 20A to the microprocessor 18. The microprocessor 18 then accomplishes programming segment 32 to determine the length of the reference blank 12A by counting the number of pulses (22A) generated by distance sensing means 22. The pulses 22A are representative of incremental changes in the linear distance that the blank 12A is being moved along its path into the machine 16. The microprocessor 18 continues to count the pulses 22A until detector means 20 senses the trailing edge of the blank 12A and, in response thereto, generates the stop event 20B to the microprocessor 18. The pulses, indicative of linear distance, are representative of the length of the reference blank 12A. 
     The microprocessor 18, as shown in segment 34, then subtracts or decrements one incremental change representative of one pulse 22A, from its cumulated count and stores such a decremented count as its reference length for blank 12A. This decremented amount is used as the reference length of the blank against which subsequent blanks are to be compared. The subtraction of the one pulse ensures that the counting means 24, at the output stage of machine 16, is enabled near the trailing edge of the formed box, but not after the trailing edge. It is preferred that the count of the blanks being moved into the machine and the count of the boxes being formed by the machine include the reference blank (12A, FIG. 1) and such inclusion is accomplished by the counting means 24 detecting the related box (12B, FIG. 1) formed from the referenced blank. If desired, by appropriate programming of processor 18, the reference blank and related box can be ignored or disregarded from the actual number of blanks and boxes associated with the production run. Once the length to be used for the reference or setup blank is determined (segment 34), the routines of the microprocessor 18 revert to their initial decision (segment 42). 
     The microprocessor 18 sequences to the normal run, as shown at the output of segment 42, and detects (segment 44) the exit event 24A indicative that the counter 24 detected a formed box. The microprocessor 18, as indicated in segment 36, increments or adds one to the count stored for the number of boxes being counted, and then disables the monitoring of signal 24A of counter 24. The microprocessor 18 then starts counting (segment 38) the representative incremental changes (pulses 22A) of movement which are transmitted by the distance sensing means 20. The microprocessor 18 continues such counting until the number of pulses counted equals the number of pulses corresponding to the length of the reference blank. When such equality is attained, the microprocessor 18 re-enables the monitoring of signal 24A from counting means 24 and waits for the formed box to pass the counter 24. The re-enablement for monitoring of signal 24A and for the waiting for the box to pass are indicated in segment 40 of FIG. 2. The routines of the microprocessor 18 then revert to monitoring the output of segment 42 and wait for the next occurring exit event 24A from means 24. Such an event 24A is indicative of the detection of the next or second box formed by the machine 16. The operation of the microprocessor 18 awaiting such detection is indicated by decision segment 44 of FIG. 2. Upon detection, the step-by-step process is repeated as indicated by the sequential segments 36, 38, 46 and 40 of FIG. 2. 
     The present invention having the flow chart of FIG. 2 and the functional representation shown in FIG. 1, is particularly suited for a machine 16 that forms packaging from initial blanks that have irregular shapes with spaced cutouts. Such a machine 16 may be further described with reference to FIG. 3 which is a side view showing the machine 16 as having means 20, 22 and 24, previously described with reference to FIGS. 1 and 2, along with the elements given in Table 3. 
     
                       TABLE 3
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Element         Nomenclature
______________________________________
52              Feed section
54              First print section
56              Second print section
58              Slotter/creaser section
60              Die cutter
62              Folder entrance section
64              Scrap conveyor
66              Belt strap conveyor
68              Folder rails
70              Folder rail support
72              Exhaust and fan assembly
74              Folder exit frame
76              Counter-ejector
78              Lower conveyor
80              Wireway
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     The feed section 52 routes and directs the blank 12A, not shown in FIG. 3 but representatively described with reference to FIG. 1, into the machine 16 wherein printing, slotting/creasing and die cutting operations are performed by sections 54-56, 58, and 60, respectively. Machine 16 is further illustrated in FIG. 4 which is a top view showing further elements that are given in Table 4. 
     
                       TABLE 4
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Element       Nomenclature
______________________________________
82            Console
84            DC drive unit
86            Isolation transformer
88            AC load center
90            L.M.C. load center
92            First print section register
94            Second print section register
96            Slotter/creaser section first
              register
98            Slotter/creaser section second
              register
100           Die cutter register
102           Upper exit frame assembly
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     The machine 16 has the detecting means 20, previously described with reference to FIGS. 1 and 2, located at its input stage and which may be further described with reference to FIG. 5 which is a view taken along line 5--5 of FIG. 4. FIG. 5 shows the detecting means 20 positioned so as to cooperate with a reflector 104, both located at the input stage 106 of the first printer section 52. The detector 20 produces a light beam 108, having a centerline 108A, which is disturbed or interrupted by blank 12A (not shown) moving along a path 110. The movement of blank 12A is accomplished by a plurality of rollers within the machine 16 and which are given, along with other elements, in Table 5. 
     
                       TABLE 5
______________________________________
Element       Nomenclature
______________________________________
112           Lower feed roll
114           Upper feed roll
116           Gripping members of roller 114
118           Print cylinder
120           Die blanket of cylinder 118
122           Impression roll
124           Gate bar
126           Support frame for reflector 104
128           Base support for means 20
130           Arm support for means 20
132           Blank support means
134           Gate bar channel
136           Gate bar member
138           Gate bar support member
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     The vertical alignment between the detecting means 20 and the reflector 104 of FIG. 5 may be further described with reference to FIG. 6 which is a view taken along line 6--6 of FIG. 5. Such a view also shows additional details of the arrangement of the gate bar 124 and the upper feed roll 114 as well as the lower feed roll 112 that is positioned behind a vertical cross tie member 140. FIG. 6 is meant to primarily illustrates a vertical arrangement in which the centerline of the detecting means 20 is approximately aligned to the centerline of reflector 104 so that the centerline (108A) of the beam 108 is substantially coaxial with both detecting means 20 and reflector 104. 
     In operation, and in a manner as discussed with reference to FIGS. 1 and 2, when a blank 12A (not shown in either FIGS. 5 or 6) is being moved along path 110 (FIGS. 5 and 6) and then passes under beam 108, the leading edge of the blank 12A breaks the optical path of beam 108. This breakage or disturbance is detected by detecting means 20 which, in turn, transmits signal 20A, which is an essential feature of the present invention, to the microprocessor 18. Another essential element of the present invention is distance sensing means 22 that cooperates with both detecting means 20 and microprocessor 18, and is shown in FIG. 7 which is a view taken along the line 7--7 of FIG. 4. 
     FIG. 7 shows the distance sensing means 22 that generates electric pulses (22A of FIG. 1) which are proportionate in number to the degree of rotation of the upper slotter shaft 142 which, in turn, is indicative of the linear distance that the blank 12A is being moved within the machine 16. The distance sensing means 22 comprises the pulse wheel 22B, connected to a slotter shaft 142, and a pulse counter 22C shown as being positioned in registration with one raised member 22D on pulse wheel 22B. Each time the counter 22C and member 22D are in alignment, a pulse 22A is generated. Because the members 22 are spaced at predetermined angular intervals from each other about wheel 22B, the repetitive alignment of 22C and 22D is indicative of the angular rotation of wheel 22B which, in turn, is indicative of the angular rotation of shaft 142. The pulse counter 22C of FIG. 7 translates the angular rotation of the rotating shaft 142 into a corresponding series of digital pulses 22A. The pulses 22A are representative of the linear distance that the blank 12A is being moved within machine 16. FIG. 7 further shows a plurality of elements related to the drive mechanism of machine 16 and which are given in Table 6. 
     
                       TABLE 6
______________________________________
Element       Nomenclature
______________________________________
150           Drive chain
152           Drive chain
154           Chain sprocket
156           Chain sprocket
158           Chain sprocket
160           Chain sprocket
162           Drive belt
164           Drive belt
166           Drive pulley
168           Drive pulley
170           Drive pulley
172           Drive pulley
174           Motor mount device with lubri-
              cant and adjustment means
176           Motor mount device with lubri-
              cant and adjustment means
178           Motor mount device with lubri-
              cant and adjustment means
180           Motor mount device with lubri-
              cant and adjustment means
182           Leading (with respect to shaft
              142) slotter shaft
184           Brace support
186           Brace support
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     Further details of the distance sensing means 22 may be discussed with reference to FIG. 8, which is a view, taken along line 8--8 of FIG. 7. FIG. 8 further shows the interconnection between the pulse wheel 22A and the slotter shaft 142. FIG. 8 also further illustrates elements which are given in Table 7. 
     
                       TABLE 7
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Element       Nomenclature
______________________________________
190           Shaft encoder of belt 164
192           Shaft encoder of belt 162
194           Shaft encoder interconnected to
              shaft 142
196           Shaft coupler of encoder 194
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     The counting means 24, which cooperates with the distance sensing means 22 of FIGS. 7 and 8, is shown in FIG. 9 which is a view along ling 9--9 of FIG. 4. FIG. 9 shows the counter 24 as located near the upper exit frame assembly 102. The upper exit frame assembly 102 has mounted thereon means 200 for adjusting the width that is related to the sizes of the blanks and boxes being processed by the machine 16. FIG. 9 further shows a support member 204. The operation of the elements given in Table 8, allows the finished box moving along path 110 to be transferred or passes from the folder exit frame 74 to the counter-ejector assembly 76 both shown in FIG. 4. 
     
                       TABLE 8
______________________________________
Element            Nomenclature
______________________________________
208                Drive shaft
210                Shaft coupler
212                Drive gear box
.sub.  214A        Drive gear
.sub. 214B         Idler gear
.sub.  214C        Driven gear
216                Driver roller
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     In operation, when the box 12B, discussed with reference to FIGS. 1 and 2, has moved past the counter means 24, the box passed onto the counter-ejector assembly 76 of FIG. 4. 
     The counting means 24 is further illustrated in FIG. 10 which is a view taken along the line 10--10 of FIG. 9. FIG. 10 shows the counter 24 as being positioned between members 220 and 222 and supported by member 220. The counting means 24 is positioned near the folder exit frame 74 (see FIG. 4) and mounted between the folder rails 68 (see FIG. 10). The counting means 24 counts the finished boxes 12B being moved into the folder exit frame 74 and toward their final destination, the counter ejector 76 of machine 16. 
     It should now be appreciated that the present invention provides means for accurately counting blanks that are formed into finished packages by the machine 16. The machine 16 shown in FIGS. 3 and 4 may be a flexofolder gluer having a counter ejector mechanism. For such a machine, without the benefits of the present invention, the blank counting is typically accomplished using a retroreflective photocell, such as detector means 20, whereby the blank is counted when the blank enters the photocell area (see FIG. 5) and its presence is detected. This detection is necessary for the subsequent timing of the counter-ejector mechanism. 
     As discussed in the &#34;Background&#34; section, the blank, such as that shown in FIG. 1A, to be counted typically may have dark printed images, such as of a black or brown color, and die cutouts, all of which may be in the path of the photocell. Typically, and without the benefits of the present invention, these dark printed images and cutouts commonly cause the photocell 20 to change state several times before the actual blank ends, thus giving multiple counts for the same blank which, in turn, may be misinterpreted by the counter-ejector mechanism. To avoid this problem, prior art techniques physically move the photocell so that its beam, such as 108 discussed with regard to FIGS. 5 and 6, only intercepts the area of the blank that does not have any dark printed images or cutouts. This physical movement causes attendant productivity losses. Further, for certain types or styles of box to be produced by machine 16, it may prove impossible to position the photocell in such a manner so as to avoid these dark printed images or cutouts. 
     The present invention, using the microprocessor techniques described hereinbefore, eliminates the counting problem commonly caused by the different images and cutouts. The microprocessor of the present invention responds to the detection of the leading edge of the blank. Such detection is dependent only on the first interruption in the beam pattern, and thus avoids the problems created by different images or cutouts of the blank. The length of the blank is already known because the automatic setup, previously described, so that the counter 24 at the output stage of machine can be unblocked prior to the trailing edge which is located in the trailing flip region of the formed box. The trailing flap region does not have any significant printing or die cutouts so that the multiple counts are not encountered. 
     It should now be appreciated that microprocessor 18 in response to a single event 20A, corresponding to the leading edge of blank entering into the input stage, operates in a sequential manner to accurately count the blank and boxes related to the machine 16 having a counterejector assembly. Although the microprocessor 18 is the preferred device, other devices may be used for the practice of this invention. For example, the microprocessor may be replaced by means for storing information, such as registers, that are responsive to the first start signal 20A for initiating counting of pulse signal 22A and terminating such counting, in a manner as previously described, in response to the stop 20B and exit 24A events. 
     In addition to accurate counting, the present invention provides a means to avoid jamming conditions related to the blanks 12A moved into a machine 16. Such avoidance is accomplished by having the microprocessor monitor the length of time that the blank 12A is within the input stage 106 of the machine. If the blank 12A remains within this input stage for an excessive amount of time, the microprocessor senses a jam and correspondingly initiates corrective actions to have the jammed blanks 12A removed. 
     The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.