Abstract:
An electro-mechanical vend-sensing system includes at least one biased member mounted on a side of the vend space having a first potential voltage. A contact strip with a second potential voltage is positioned beneath the biased member. A controller circuit senses when the biased member contacts the contact strip, which indicates that a article has been appropriately vended to the customer.

Description:
This application claim priority to U.S. Provisional Patent Application No. 61/750,176, the contents of which are incorporated by reference into the present application. 
    
    
     FIELD 
     The present invention relates to machines that dispense selected articles, and more particularly, to a sensing system that reliably detects dispensed articles. 
     BACKGROUND 
     Glass front vending machines are machines designed for vending articles of various sizes and shapes, including packaged snack foods, merchant cards, and consumer articles. These machines generally have a selector panel, located off to one side of the glass front, and use some form of horizontal trays, partitioned into columns, to store the articles to be vended. 
     Typically, after a consumer makes the requisite payment and enters the desired selection on the selector panel, the forward-most article from the selected column is ejected or dislodged, and the article drops freely into a delivery hopper at the bottom of the machine. The space that the article falls through is the area between the fronts of the columns and the back of the glass front, commonly referred to as the vend space. 
     It is important that vending machines operate in a reliable manner and provide consumers with the selected article without the need to expend unusual effort to obtain the article. With this said, there exists various events that can compromise the reliability of vending machine operations. For example, the spatial orientation and wrinkling of packages, the content distribution of packages, the tumbling of packages through the vend space, and empty spiral pockets can all contribute to the mis-vending of articles. 
     Various detection schemes have been employed to detect when an article passes through the vend space. These all suffer from various shortcomings, including failing to detect smaller articles that escape through an electromagnetic beam or multiple beams or failing to impart sufficient force on impact or vibration on a sensor located at the bottom of the vend space. 
     SUMMARY 
     The present invention discloses an electromechanical vend-sensing system. The system includes at least one biased member mounted on a side of the vend space having a first potential voltage. A contact strip with a second potential voltage is positioned beneath the biased member. A controller circuit senses when the biased member contacts the contact strip, which indicates that an article has been appropriately vended to the customer. 
     In an embodiment multiple biased members are provided in order to obstruct the vend space. The biased members can be straight or bent, or the biased members can be arranged in a linear or overlapping pattern. An important aspect is that the biased members are sufficiently close together to prevent an article from slipping past without impacting the biased members yet flex downward from the weight of the article so that the article can pass through the vend space to the customer. 
     These and other aspects, features, and advantages of the invention will become apparent upon review of the following description taken in connection with the accompanying drawings. The invention, though, is pointed out with particularity by the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic diagram of the present invention. 
         FIG. 2  shows a pattern of electromechanical sensors in a vend-sensing system. 
         FIG. 3  shows a top view of the electromechanical sensors of  FIG. 2  with a package about to impact the electromechanical sensors. 
         FIG. 4  shows a side view of the electromechanical sensors of  FIG. 2  with a package impacting and deflecting the electromechanical sensors. 
         FIG. 5  is a schematic diagram of the electromechanical switches in the open position. 
         FIG. 6  is the schematic diagram of  FIG. 5  with three of the electromechanical switches closed to indicate that a package has deflected the electromechanical sensors corresponding to the closed switches. 
         FIG. 7A  is a first embodiment of a pattern of electromechanical sensors in a vend-sensing system. 
         FIG. 7B  is a second embodiment of a pattern of electromechanical sensors in a vend-sensing system. 
         FIG. 7C  is a third embodiment of a pattern of electromechanical sensors in a vend-sensing system. 
         FIG. 7D  is a fourth embodiment of a pattern of electromechanical sensors in a vend-sensing system. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention is directed to a vend-sensing system that reliably detects when an article has been dispensed. This can be achieved by providing at least one biased member that is deflected by an article downward to touch a contact strip to close an electrical circuit. The biased member(s) are sufficiently sized to span the cross-sectional area of the vend space and are configured to have an inter-member spacing small enough to detect the smallest article being dispensed. 
     When an article is released, it falls through the vend space, deflects the biased member(s), and a detector senses the closed circuit. The detector subsequently signals that the article has been dispensed. A machine control unit receives the signal and terminates the vending cycle. If, during the vending cycle, the machine control unit fails to receive the signal from the detector, the machine control unit initiates a corrective action. In this manner, the vend-sensing system of the present invention is capable of reliably detecting dispensed articles and taking appropriate corrective action when an article is mis-vended. 
       FIG. 1  shows a vending machine  10  equipped with the vend-sensing system  100 . In general, vending machine  10  includes a cabinet  12  having opposite sidewalls, a back wall, a top wall and a bottom wall, which cooperatively define a forwardly facing cavity  14  arranged to have a plurality of tray assemblies  16  mounted therein at a plurality of vertically spaced levels. 
     Vending machine  10  is equipped with a dispensing mechanism with multiple dispensing units  17  arranged across each tray assembly  16 . Each tray assembly  17  may contain a plurality of motorized horizontally arranged helical spirals that are spaced from one another widthwise of the tray assembly  16 , and each of which extends longitudinally in a front-to-rear depthwise direction of the tray assembly  16 . Each spiral is connected to a driving chuck of a respective drive motor, which rotates the spiral about the longitudinal axis of the spiral. 
     Spaced in front of the front edges of the tray assemblies  16  is a door  18  that can be opened and locked. Door  18  typically has a glass front so customers can view the leading articles being offered by vending machine  10 . Door  18  may further include a selector panel  20 , which includes a mechanism for accepting payment from the consumer and for selecting an article  26 . 
     After a consumer selects a desired article  26 , the vending cycle may be initiated by causing the respective spiral drive motor assembly of the respective column to rotate through a sufficient angular distance, in order to advance all of articles  26  nested in the turns of the respective spiral. Articles  26  are advanced until the forward-most article  26  loses support from below as it reaches the front of the respective tray support surface and drops through a vend space  24  behind glass door  18 , down into a vend hopper  22 , where it can be retrieved by the consumer. 
     Proximate to vend hopper  22  in vend space  24 , vend-sensing system  100  may be disposed to reliably detect that article  26  has actually been dispensed.  FIG. 2  depicts vend-sensing system  100 . As indicated in  FIGS. 2-4 , vend-sensing system  100  comprises a plurality of biased members  102  arranged in two rows extending longitudinally in a side-to-side direction and a plurality of rows extending latitudinaly in a depthwise front-to-back direction to substantially obstruct vend space  24 . A contact strip  4   a  and  4   b  is positioned on each side of vend space  24  below biased members  102 . A machine control unit  106  (shown in  FIGS. 5-6 ) is provided to sense contact between biased members  102  and engagement strip  104 . 
     More specifically, vend-sensing system  100  includes a frame  108  positioned on opposite sides of vend space  24 . Mounted to each frame  108  is a plurality of biased members  102 . Biased members  102  are arranged in two rows extending longitudinally in a side-to-side direction across each frame  108  and extend outward across vend space  24  toward the opposite side. Biased members  102  on opposite frames  108  can be aligned with each other leaving a small space  110  between opposing linear biased members that is sufficiently small to prevent article  26  from slipping through space  110  without impacting biased members  102 . Biased members  102  are also spaced sufficiently close together in the longitudinal direction to prevent article  26  from slipping past without impacting biased members  102 . 
     When article  26  is released, it falls through the vend space  24  and deflects one or more biased members  102 . On impact from article  26 , bias members  102  temporarily flex downward from the weight of article  26 , so that article  26  may pass through the vend-sensing system  100 . After article  26  passes, bias members  102  return to the extended, resting state position. 
     Biased members  102  are wire-like whiskers that can be fabricated from a pre-formed resilient material (e.g. spring temper steel or formed or coiled stainless steel wire) with a stiffness determined by diameter, length, spacing, material, and modulus of elasticity. Biased member  102  must be light enough to deflect sufficiently to cause a switch closure upon impact by the lightest vended article  26 , but not impede the dispensing of article  26  causing a mis-vend. Bias members  102  can be spring-loaded to ensure that they extend out to the farthest length possible and quickly return to the resting state after being deflected. 
     Biased members  102  can be implemented in a variety of arrangements corresponding with the size of the smallest article  26  to be vended.  FIG. 7  shows the embodiment illustrated in  FIG. 2 . As shown, a particularly small article  26 , such as a merchant card  26   a , could slip through biased members  26  that do not sufficiently cover the cross-sectional area of vend space  24 . To solve this problem, biased members  102  can be shaped with gentle curves or sharp bends, as shown in  FIGS. 7B and 7C , respectively.  FIGS. 7B and 7C  each show two merchant cards  26   a  being vended and engaging biased members  102 . It is apparent that no matter the spatial orientation of merchant card  26   a  as it enters vend space  24 , it will impact at least one biased member  102  and flex it downward to engage contact strip  104 . This is because biased members  102  are sized to span the cross-sectional area of the vend space  24  with an inter-member spacing small enough to detect merchant card  26   a.    
     Alternatively, biased members  102  can be arranged on top of each other, as shown in  FIG. 7D , and slide apart from the weight of article  26 . Similarly, biased members  102  are sized to span the cross-sectional area of the vend space  24  with an inter-member spacing small enough to detect merchant card  26   a.    
     Contact strip  104  is combined to each frame  108  and positioned beneath biased members  102 . When biased member  102  is deflected downward from the weight of article  26 , it touches contact strip  104 .  FIG. 4  shows a pair of opposing biased members  102  flexing downward from the weight of article  26 . At the maximum deflection, biased member  102  touches contract strip  104 . 
     Turning to  FIGS. 5 and 6 , a circuit diagram illustrates the closing of switches  112 , which schematically represent biased members  102  and contact strip  104 . Switches  112  are each normally open and independent of each other to correspond with biased member  102  being in a resting state. When biased member  102  is flexed downward from the weight of article  26  it temporarily touches contact strip  104  to close the electrical circuit.  FIG. 5  shows all of switches  112  in an open position.  FIG. 6  shows three switches  112   a ,  112   b , and  112   c  in the closed position indicating that the weight of article  26  has sufficiently deflected biased member  102  to engage contact strip  104  to temporarily close the electrical circuit. 
     Biased members  102  are optimally connected to the chassis ground or zero potential voltage of vending machine  10 , with a positive potential, signal voltage applied to contact strip  104 . For additional “fail safe” operation, the two rows of biased members  102  shown in  FIG. 2  may be electrically isolated and applied as two switch closures to controller  106 . In the event that biased member  102  on one side becomes permanently shorted to contact strip  104 , its corresponding biased member  102  on the other side will continue normally to sense articles  26 . 
     Switches  112  are electrically coupled to machine controller  106 . Controller  106  monitors and ensures the proper operation of the vending machine  10 . Machine controller  106  communicates with the vending drive motors (controlling spiral rotations) of dispensing unit  17 . A debounce circuit can be used by controller  106  to smooth what is normally expected to be an erratic closure-time pattern during the brief interval as article  26  falls and deflects biased members  102  downward to engage contact strip  104 . 
     Machine controller  10  includes logic and associated circuitry to interface and communicate with vend-sensing system  100  and dispensing unit  17 . Such logic may include, for example, a processor with executable instructions. The software and hardware implementing machine controller  106  can be implemented in many different embodiments of software, firmware, and hardware. The actual software code or specialized control hardware used to implement the present invention is not limiting of the present invention. 
     If, during the vending cycle, machine controller  106  does not register that article  26  has been dispensed, machine controller  106  may initiate a corrective action. Such corrective action may include, for example, communicating with selector panel  20  to notify the consumer that he is given the choice to have his form of payment refunded or to select another column&#39;s article  26 . For example, if machine controller  106  does not register that a selected article  26  has been dispensed because a spiral pocket was left empty or the selected article  26  is stuck, machine controller  106  may communicate with selector panel  20  to display a message that the consumer may select another article  26 . In this manner, vend-sensing system  100  will ensure that vending machine  10  will either properly vend an article  26  or perform a corrective action to avoid mis-vending. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it should be understood by those of ordinary skill in the art that various changes, substitutions and alterations can be made herein without departing from the scope of the invention as defined by appended claims and their equivalents.