Abstract:
The present invention provides a portable counter and corresponding method for counting articles arranged in a stack, like compact discs and dvds. The portable nature of the counter enables the counter to be brought and placed adjacent to the stack of discs, which are often times relatively much heavier than the counter, for providing an accurate count of the discs. The counter further employs several error checking type functions, which serves to insure and enhance the accuracy of the count, as well as alert the user of potential problems.

Description:
FIELD OF THE INVENTION 
     The present invention relates to counters for counting one or more articles arranged in a stack. More particularly, the present invention relates to a counter for counting discs of the type including compact discs (cds) and dvds arranged on a spindle. 
     BACKGROUND OF THE INVENTION 
     Compact discs are frequently handled in large volumes, this is especially true for manufacturers and distributers of compact discs. Correct counts are important to insure customer orders are filled accurately, where shipping too few discs can often result in unhappy customers, and shipping too many discs will often unnecessarily eat into the profits of the manufacturer or distributer. When the volumes become large it becomes ever increasingly more inefficient to manually count the discs. Correspondingly accurate and efficient means for counting a stack of compact discs is desirable. 
     In the past, various techniques have been tried including simply measuring the height of a stack of discs. In other instances manufacturers have weighed the stack of discs. By knowing the unit height or the unit weight, manufacturers previously attempted to compute the total number of units, based upon the total weight or the total height of the stack of discs. However when compact discs or dvds are manufactured they are allowed a degree of variance within predetermined tolerances. These variances can sometimes make the methods of weighing or measuring the height of the stack somewhat suspect. Furthermore such techniques require that the characteristics of the spindle be taken into account. Consequently more accurate techniques are desirable. 
     Other previous counters have been developed, two examples of which are described in U.S. Pat. No. 4,994,666 and U.S. Pat. No. 5,315,107, which have taken advantage of an inherent physical feature associated with stacks of discs. When stored, discs generally provide a spacing between each adjacent pair of stacked discs. The spacing or gap is caused by a raised ridge near the center or hub of the disc, sometimes referred to as a boss. The ridge generally extends above the planar surface of the disc on at least one of the sides of the disc. These previous counters use an illuminated source of light having a path, which travels in a direction substantially parallel to the surface of the discs. The previous counters then attempt to detect the light that exits on the other side of the stack of discs. The source of light and the device used to detect the light are then moved relative to the stack of the disc, wherein the path of light is selectively interrupted when the light is received by the stack of discs proximate the edge of a disc, and is allowed to propagate through the discs when the light is received by the stack of discs proximate the gap or spacing between the discs. 
     These devices are generally larger than the stack of discs and are typically fixed in place. It is generally necessary to bring the discs to be counted to these counter devices and for the stack of discs to be loaded into the machines. For convenience sake it would be beneficial to develop a portable device that could be brought to the discs without sacrificing the accuracy of the counter. 
     Furthermore, to the extent that the accuracy of the count could be further enhanced, or to the extent that the counter could detect potential problems or errors, such a counter would be further beneficial. 
     SUMMARY OF THE INVENTION 
     The present invention provides a portable counter for counting one or more articles arranged in a stack. The portable counter comprises a housing, a radiation source, a radiation detector, one or more motors, and a processor. 
     The housing is sized to be hand carried, the housing having a handle, and a scan surface for facing toward and placing adjacent to the stack of one or more articles to be counted. 
     The radiation source is oriented so as to produce radiant energy which radiates in a direction toward the stack of articles positioned adjacent to the scan surface. The radiation detector is spaced apart from and oriented toward the radiation source so as to selectively receive radiant energy from the radiation source and produce a corresponding output signal when the direct path between the radiation source and the radiation detector is unobstructed. The direct path between the radiation source and the radiation detector crosses the space, where the stack of one or more articles to be counted is located. 
     One or more motors are coupled to the radiation source and the radiation detector for moving both the radiation source and radiation detector along the length of the scan surface and the stacked articles positioned adjacent thereto. As the radiation source and the radiation detector move relative to the adjacent stack of articles the direct path between the radiation source and the radiation detector alternatively passes through the one or more articles and the gaps on either side of the one or more articles. The direct path is obstructed when the path passes through one of the articles. 
     A processor is coupled to receive the output signal of the radiation detector, and includes a counting module for determining the number of articles intersected by the direct path between the radiation source and the radiation detector, as the radiation source and the radiation detector travel along the scan surface of the housing and the height of the stack of articles positioned adjacent thereto. 
     In at least a further embodiment the processor further includes a distance tracking module for determining the overall height of the stack of articles, and an error checking module for comparing the number of articles intersected as determined by the counting module with the number of discs corresponding to the overall height of the stack of articles as determined by the distance tracking module. 
     In at least a still further embodiment the counting module determines a count based upon at least two passes of the radiation source and radiation detector respective to the stack of articles, and in at least two different directions. 
     The present invention further provides a method for counting one or more articles arranged in a stack. Specifically the method includes radiating energy from a radiation source in a direction nearly parallel to the one or more substantially planar surfaces of the articles being counted, and moving the radiation source along the height of the stack of articles, while generally maintaining the direction the energy is being radiated. 
     The radiated energy is selectively received at a radiation detector, which moves in conjunction with the radiation source, when the direct path between the radiation source and the radiation detector is not obstructed by the one or more articles being counted. The number of articles intersected by the direct path is determined, while the radiation source and the radiation detector traverse the height of the stack of articles. Additionally, the overall height of the stack of articles is determined. 
     After determining the number of articles intersected and the overall height of the stack of articles, a comparison is made between the determined number of articles intersected and a number of articles consistent with the determined overall height of the stack of articles for detecting any inconsistencies or errors. A count corresponding to the number of articles, and any inconsistencies or errors is then displayed. 
     By making multiple different types of measurements and comparing the results, the chances of detecting and reconciling an error is significantly improved. 
     These and other objects, features, and advantages of this invention are evident from the following description of a preferred embodiment of this invention, with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of one example of a counter for counting a stack of articles in accordance with the present invention, wherein the counter is shown placed adjacent to a stack of article in a manner consistent with counting the articles; 
     FIG. 2 is a cross-sectional view illustrating several disc type stacked articles positioned on a spindle; 
     FIG. 3 is a side view of the counter, shown in FIG. 1, with the side cover and front or scan surface removed exposing the interior of the counter; 
     FIG. 4 is an orthogonal view of counter, as shown in FIG. 1, similar to FIG. 3, with side cover and the front or scan surface removed; 
     FIG. 5 is a bottom orthogonal view of the platform, shown in FIGS. 3 and 4, with the radiation source and radiation detector placed thereon; 
     FIG. 6 is bottom cross-sectional plan view illustrating the platform and corresponding radiation source and radiation detector, shown in FIGS. 3-5, in relation to a stack of articles positioned adjacent thereto. 
     FIG. 7 is a block diagram of the electronic circuitry associated with the counter, shown in FIGS.  1  and  3 - 6 ; 
     FIG. 8 is a more detailed circuit schematic of the counter, shown in FIGS.  1  and  3 - 7 ; and 
     FIG. 9 is a flow diagram of the scanning operation being performed by the processor, shown in FIGS.  7  and  8 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described presently preferred embodiments with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
     FIG. 1 illustrates a counter  10 , in accordance with at least one embodiment of the present invention, for counting one or more articles arranged in a stack. The counter  10  is shown placed adjacent to a stack  12  of discs  14  on a spindle  16 . The stack is adjacent to a front panel  18  or scan surface portion of the counter&#39;s  10  housing  19 . The front panel  18  has a concave surface forming a shallow recess within which the stack of discs can be partially positioned. By allowing the stack  12  of discs to be partially positioned within the recess of the front panel  18 , a direct path between a radiation source and a radiation detector, both of which are shown in FIGS. 4-6, to intersect the outer edges  20  of the discs  14  in the stack  12 . 
     The opening  22  in the front panel  18 , which exposes the radiation detector, is shown. Further shown in FIG. 1 is the battery compartment  24 , which in the preferred embodiment receives a rechargeable lithium-ion battery. The rechargeable lithium-ion battery supplies portable power to the electronic circuitry and electro-mechanical elements of the counter  10 , thereby freeing it from the mains power supply during regular operation. 
     FIG. 2 illustrates a cross-sectional view of several discs  14  stacked on a spindle  16 . The cross-sectional view of the discs  14  further illustrate a raised center ridge  26  or hub, also known as a boss. The raised center ridge  26  typically prevents the discs  14  from lying flush with other adjacent discs toward their outer edge  20 . Consequently, gaps  28  or spaces are generally formed therebetween. It is through these gaps  28  that radiant energy is caused to be selectively propagated and to be correspondingly detected across a path which intersects the stack  12  of discs  14 , the direct path being shown in FIGS. 4 and 6, and being subsequently discussed in greater detail. 
     FIGS. 3 and 4 both illustrate the counter  10 , with both its front panel  18  and side cover removed, thereby exposing the internals of the counter  10 . FIG. 3 is a side plan view. FIG. 4 is an isometric view. 
     Both FIGS. 3 and 4 also illustrate additional exterior features. For example, the housing  19  additionally includes a handle  30  by which a user can grip and maneuver the counter  10 . The counter  10  additionally includes a display  32 , which is visible exterior to the counter through a clear window in the housing, and a push button  34  which extends partially through the housing  19 . 
     Internally, the counter  10  includes an optical platform  36  upon which a radiation source  38  or laser/lens assembly, and a radiation detector  40  or radiation detector assembly is received. Further positioned on the optical platform  36  is a motor/gear box assembly  42 , which in combination with a rail  44  and rack  46 , guide and propel the platform along the rail  44  within the housing  19 . In the preferred embodiment the rail  44  extends substantially vertical, thereby facilitating corresponding vertical motion of the platform  36 . 
     At the upper end of the rail  44  is an upper interrupter switch  47 . A corresponding lower interrupter switch, shown only in FIG. 8, is located proximate the lower portion of the rail  44 . The interrupter switches include a slot between two corresponding sections. The two corresponding sections include a respective light emitting diode and photo detector. The photo detector receives light from the light emitting diode except when an opaque object occupies the slot between the two corresponding sections. A flag located on the platform  36  is located so as to interfere with the reception of light by the photo detector in the interrupter switches, when the platform is respectively at a defined lower most position and a defined upper most position along said rail  44 . The interrupter switches provide feedback to the processor. 
     A balance spring  48  and corresponding pulley  50  are coupled to both the platform  36  and the housing  19  frame to provide a counter balance force which pulls on the platform  36  in the opposite direction to gravity. 
     A printed circuit board  52  including the processor and related electronic circuitry is mounted behind the rail  44 . The printed circuit board  52  including the processor is coupled to the platform  36  and the corresponding components via a flexible cable  53 . The battery assembly  54  is similarly mounted behind the rail  44 . 
     FIG. 5 illustrates an isometric view of the optical platform  36 , as well as the radiation source  38  and radiation detector  40  located thereon. As illustrated in the preferred embodiment, the radiation source assembly  38  includes a laser and lens diode  56  and a mirror  58 . The laser diode  56  produces a beam of light, which is reflected off of the mirror  58  and toward the radiation detector  40 . The particular path  60  of the beam of light being illustrated in FIGS. 4 and 6. 
     An opening  62  in the radiation detector  40  allows an unobstructed beam of light from the radiation source  38  to enter the radiation detector  40 . Internal to the radiation detector  40 , the detector  40  includes a pair of mirrors  64  and  66 , and a photo detector  68 . At least one example of the path  70  the beam of light will take within the radiation detector  40 , when otherwise unobstructed, is illustrated in FIG.  6 . When the photo detector  68  receives the beam of light, the photo detector  68  produces a corresponding electrical signal, which is coupled to and used by the processor  82  discussed below. 
     FIG. 6 further shows the path of light in relation with a stack  12  of discs  14 . As can be seen the light path  70  crosses through the stack  12 . As noted previously this allows the light path  60  to be alternatively transmissive and blocked dependent upon the position of the radiant source  38  and the radiant detector  40  with respect to the discs  14  within the stack  12 . The light path is blocked when the light path is aligned with a disc  14 , when the light enters the stack  12 . The light path is transmissive, when the light path is aligned with the space  28  between the discs  14  when the light enters the stack  12 . 
     FIG. 7 illustrates a block diagram  80  of the electronic circuitry associated with the counter  10 . The block diagram  80  includes a processor  82 . The processor includes a counting module  84 , a distance tracking module  86 , an error checking module  88 , and a display module  90 . 
     The counting module  84  generally receives the output from the radiation detector  40  and develops a count corresponding to the number of detected discs  14  that are in the stack  12 . 
     The distance tracking module  86  is coupled to the motor  42  and receives signals therefrom from which the processor  82  can determine distance traveled during the scanning of the discs  14 . In the preferred embodiment the motor  42  is a gear motor with an encoder, which as the motor turns, the associated gear engages the rack  46  and the motor  42 . The platform  36  coupled thereto is propelled in the appropriate direction, and the encoder produces a number of pulses corresponding to the distance traveled. The overall distance traveled is theoretically related to the combined thickness of the stacked discs  14 . If you know the general thickness of a single disc  14 , the same can be used in connection with the overall stack height to approximate the number of discs  14 . 
     The error checking module  88  is coupled to both the counting module  84  and the distance tracking module  86 . The error checking module compares the results from each of the independent methods of calculating the number of discs  14  in the stack  12 , and confirms consistency between the two. 
     In an attempt to further enhance the accuracy of the counter  10 , in addition to the counting module  84  determining the number of discs  14  intersected in a first direction, in the preferred embodiment, the counting module  84  repeats the analysis in a second direction as the platform  36  returns to its original start position. The counting module  84  relays the results of the analysis in both directions to the error checking module  88 , which is then used to further confirm the accuracy of the results. 
     The error checking module  88  further stores the data for several preceding counts, which is also used to confirm the accuracy of the present count. So long as the type of disc  14  being counted remains the same, the data is helpful in confirming the accuracy of the count. When the type of disc  14  being counted changes, the preferred embodiment enables one to manually clear the data from the preceding counts. In at least one embodiment of the present invention, four such sets of data from preceding counts is stored and used for comparison. 
     The display module  90  is coupled to the error checking module and displays the results of the scan including the number of items counted on the display  32 , as well as any errors detected. 
     In at least one embodiment, the counting module  84 , the distance tracking module  86 , the error checking module  88  and the display module  90  are comprised of programming instructions and data for execution on the processor  82 . 
     FIG. 8 illustrates a more detailed circuit schematic  100  of the block diagram  80  of the electronic circuitry illustrated in FIG.  7 . The more detailed circuit schematic  100 , similarly includes a processor  82 . In the preferred embodiment the processor is a 68HC711 micro-controller. The processor receives power from a voltage regulator  102 , which produces a regulated 5V output from an unregulated voltage from a battery  104 . In addition to receiving power from the battery  104 , via the voltage regulator  102 , the processor  82  additionally monitors the output voltage of the battery  104 , via a voltage divider network  106 . In this way the processor  82  can produce an over voltage warning, if for example the battery voltage exceeds 8.5V, and produce an under voltage warning, if for example the battery voltage falls below 5.7 volts. 
     The processor is further coupled to an oscillator clock circuit  108  for providing the necessary clocking signal for the operation of the processor  82 . The processor is similarly coupled to the upper interrupter limit switch  47 , the lower interrupter limit switch  110 , and push button switch  34 . 
     The processor  82  is coupled to the motor  42 , via a motor controller  112 , which converts the control signals received from the processor  82  to the control signals expected by the motor  42 . The photo detector is coupled to the processor via an amplifier/buffer circuit  114 . One such suitable circuit for the amplifier/buffer circuit is a non-inverting operational amplifier circuit. 
     Additionally coupled to the display is a potentiometer  116 , which is capable of providing contrast control. 
     FIGS. 9A-9D illustrate a flow diagram of the scanning operation being performed by the processor  82 , consistent with at least the preferred embodiment of the present invention. 
     From the foregoing, it will be observed that numerous modifications and variations can be effected without departing from the true spirit and scope of the novel concept of the present invention. It is to be understood that no limitation with respect to the specific embodiments disclosed herein is intended or should be inferred. The disclosure is intended to cover, by the appended claims, all such modifications as fall within the scope of the claims.