Abstract:
A method of moving an elevator to a product location in a vending machine to receive product from the product location, including the steps of: providing an indicator associated with each product location; providing a sensor associated with the elevator; moving the sensor first to a position near an expected position of one of the indicators; and searching for an actual position of the indicator. An apparatus for performing the method is also disclosed.

Description:
RELATED APPLICATIONS  
       [0001]     The present application claims priority to U.S. Provisional Patent Application Ser. Nos. 60/701,269 filed Jul. 21, 2005, the contents of which are incorporated herein by reference, and is a continuation of U.S. patent application Ser. No. 11/421,935, the contents of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     In the past, vending machines have been used to dispense beverages. In one common configuration, cans or glass or plastic bottles are stacked in a vertical or offset-vertical columns and dispensed from the bottom of the columns into a holding area below the columns where the customer can retrieve the beverage. Generally, a funnel-type diverter will be used to divert the beverage to the location of the holding area and also to prevent the beverage container from being damaged during the drop. This configuration requires that the column be shorter than the height of the machine so that the beverage can be dropped into the holding area below the column. As a result, storage space that could be used to increase capacity is wasted on the holding area. This is undesirable because in the vending industry it is preferable to have the maximum capacity of product in a machine of a given size in order to maximize sales and maximize the time between product restocking.  
         [0003]     Additionally, vending machines incorporating products, typically snacks and candy, have utilized trays having horizontal columns of product placed between each revolution of a helical shaft. The shaft is rotated one revolution, which causes an item near the end of the screw to be forced forward and become disassociated from the helical shaft. Typically, the product will drop from the front of the tray into a holding area that can be accessed by the customer to retrieve the item. The holding area must be lower than the lowest tray so that an item may drop into the holding area. As a result, space associated with the holding area is not used for storing product, thus wasting some usable space. Moreover, the helical shaft is not particularly suited for beverage containers.  
         [0004]     Another type of vending machine, such as that shown in U.S. Pat. No. 6,556,889 to Rudick et al., uses an elevator to receive product that is dropped from sloping trays. The product slides down the sloped trays by the force of gravity into the elevator that is moveable to a location adjacent the tray. An actuator located between the lowermost beverage and the elevator selectively allows a beverage to pass into the elevator. The elevator then moves to a second location whereby a conveyor belt in the elevator conveys the beverage to one side of the elevator where it is conveyed into a holding area to the side of the elevator. However, because the vending machine of the &#39;889 patent utilizes sloped shelves, some of the vertical capacity of the vending machine is wasted. Moreover, because product dispensation relies on sloping shelves, jamming of product can occur if the slope is insufficient to allow for simultaneous movement of the column of product (particularly if product spillage occurs causing sticky trays) or of the product is heavy (such as large glass bottles) and applies too much force to the product dispensation actuator.  
         [0005]     Therefore, there is a need for a vending machine, particularly a beverage vending machine, that does not waste space for a holding area for delivery of the product or for product trays that require the tray to be sloping for delivery of the product to the consumer.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention provides a method of moving an elevator to a product location in a vending machine to receive product from the product location, including the steps of: providing an indicator associated with each product location; providing a sensor associated with the elevator; moving the sensor first to a position near an expected position of one of the indicators; and searching for an actual position of the indicator. The present invention also provides an apparatus for performing the method. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a front perspective view of a vending machine tray according to an embodiment of the present invention;  
         [0008]      FIG. 2  is an enlarged partial view of the vending machine tray of  FIG. 1 ;  
         [0009]      FIG. 3  is a front perspective view of a partially disassembled vending machine tray according to an embodiment of the present invention;  
         [0010]      FIG. 4  is a front perspective view of a partially assembled vending machine tray according to an embodiment of the present invention;  
         [0011]      FIG. 5  is a front perspective view of two unattached vending machine trays according to an embodiment of the present invention;  
         [0012]      FIG. 6  is a front perspective view of two attached vending machine trays according to an embodiment of the present invention;  
         [0013]      FIG. 7  is a top view of two attached vending machine trays having product loaded therein according to an embodiment of the present invention;  
         [0014]      FIG. 8  is a rear perspective view of a partially assembled vending machine tray according to an embodiment of the present invention;  
         [0015]      FIG. 9  is a partial view of an elevator for use with the tray according to an embodiment of the present invention with the product dispenser drive retracted;  
         [0016]      FIG. 10  is a partial view of an elevator for use with the tray according to an embodiment of the present invention with the product dispenser drive extended;  
         [0017]      FIG. 11  is a front perspective view of a partially assembled vending machine tray with a product present indicator retracted and extended according to an embodiment of the present invention; and  
         [0018]      FIGS. 12 and 13  are diagrams of an elevator locating procedure according to an embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]     While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated.  
         [0020]     Referring to  FIG. 1 , the present invention is a vending machine dispenser tray  10 . The tray  10  is most suited for vending beverage items such as soda, water, juices, etc. although nothing prevents application of this invention to non-beverage items. The tray  10  has a front  11  and comprises rows  12  that are defined by upstanding walls  14  attached to a base  16  having a front  17 . As shown in  FIG. 2 , at an end  18  of the walls  14  is attached a pair of resilient arms  20 . Two resilient arms  20  extend from each wall  14 , such that a pair of arms  20  from adjacent walls  14  cooperate to at least partially block the end of each row  12 . Located within a channel  13  formed within each row  12  of the base  16  is a threaded shaft  22  that is threaded into a product backstop or drive member  24 .  
         [0021]      FIGS. 3 and 4  show that each threaded shaft  22  has a gear  26  that is located near the front  17  of the base  16 . Each gear  26  is driven by a rotatable drive shaft  28  having a mating gear  30 . The drive shaft  28  further defines a smooth outer surface  32 . Also provided in the front  17  of the base  16  and adjacent the drive shaft  28  is a linear coil spring  34  wrapped around a rotatable spring shaft  36 . An end of the spring  34  is attached to the drive shaft  28 , and the other end of the spring  34  is attached to the spring shaft  36 . The drive shaft  28  and spring shaft  36  are mounted to the base  16  into a drive shaft hole  38  and onto a spring shaft pin  40 , respectively. As the drive shaft  28  is rotated clockwise, the spring  34  is wrapped around the smooth outer surface  32  of the drive shaft  28  and the spring shaft  36  is rotated counterclockwise as the spring  34  uncoils. However, because the spring  34  is wrapped around the drive shaft  28  in the opposite direction to the spring shaft  36 , the natural bias of the spring  34  causes the spring  34  to resist being wrapped onto the drive shaft  28 . Therefore, the natural bias of the spring  34  urges the drive shaft  28  counterclockwise.  
         [0022]     As discussed above, the product drive member  24  is threaded onto the threaded shaft  22 . Because the drive shaft  28  is urged counterclockwise, the drive shaft  28  urges the threaded shaft  22  clockwise through the mating gears  26  and  30 . The result of the threaded shaft  22  being urged clockwise is that the product drive member  24  is urged to the front  11  of the row  12 .  
         [0023]     Referring to  FIG. 5 , the right side  42  of the base  16  defines interlocking fingers  44  and the left side  45  of the base  16  defines interlocking fingers  46 . When the left side of a base  16  is brought next to the right side of another base  16  the fingers interlock such that the two bases  16  may be locked together to make a larger tray  10 , as shown in  FIG. 6 .  
         [0024]     In the preferred embodiment, the tray is comprised of two rows  12 . Therefore, by locking the bases  16  together, a larger tray  10  comprised of any even number of rows  12  can be used within vending machines of various sizes. However, nothing should be construed to limit the invention any particular number of rows and more or fewer rows may be implemented within a tray without departing from the scope of the present invention, for example bases of only a single row that lock together to form a larger tray.  
         [0025]     In order to use the device of the present invention, the bases  16  are interlocked together to form a proper width tray  10  suitable for a particular vending machine. Multiple rows of trays are further provided within the vending machine and the rows  12  of the trays  10  are filled with product  100  to be vended, as shown in  FIG. 7 . The product  100  may be of various sizes as large as the width of the row  12  or as small as slightly larger than half the width of the row  12 . To maintain product near the front of the row, the product drive member  24  abuts the rearmost product  100  and the force provided by the spring  34  urges the product  100  within the row  12  against the resilient arms  20  at the front  11  of the tray  10 . In this manner the product  100  awaits vending by the machine.  
         [0026]     When the time for vending the product  100  arrives, an elevator  102 , as shown in  FIG. 8 , is moved to the desired product row  12  for vending. The elevator  102  comprises a cup for holding the vended product and transporting it to a customer pickup station (not shown). The elevator  102  determines the precise location of the product to be vended by first traveling to an expected location of the row  12  within the vending machine for the product. However, because the vending machine cabinet may have warped due to being placed on uneven ground or merely due to manufacturing tolerances, the expected location may not be the precise location of the row  12  containing the product to be vended. In order to find the precise location, the elevator  102  begins searching in the area of the expected location until a sensor  103  carried by the elevator  102 , such as a Hall Effect sensor or a reed switch, locates an indicator  105 , such as a magnet, such indicator  105  being located with respect to each row  12  location. Once the elevator has found the indicator associated with the row  12 , an electromechanical device (not shown) within the elevator  102  extends a product dispenser drive  104  from a retracted position ( FIG. 9 ) to an extended position ( FIG. 10 ). The product dispenser drive  104  has a cooperating shape to that of the drive shaft  28  and mates with the drive shaft  28  to rotate it. As the drive shaft  28  is rotated by the elevator  102 , the product drive member  24  forces product  100  toward the elevator  102  and past the resilient arms  20 . Once the product  100  passes the resilient arms  20 , it enters the elevator  102  and the product dispenser drive  104  of the elevator  102  stops rotating. The product dispenser drive  104  of the elevator  102  is then retracted and the elevator  102  takes the product  100  for dispensing to a customer.  
         [0027]     Optionally, a sensor  103  may be provided on the elevator that detects the presence of an indicator  48  with respect to the product drive member  24 , as shown in  FIG. 11 . While product  100  is located within the row  12 , the indicator  48  is retracted and not detected by the sensor. In this manner, the vending machine determines that product  100  remains in a particular row. When product  100  no longer is located within the row  12 , the indicator  48  is extended and detected by the sensor, and thus detects the absence of product  100  before attempting to vend the product and alerts a consumer to make an alternate product choice.  
         [0028]     Alternatively, rather than detecting the presence or absence of product directly, the product elevator  102  can attempt to vend product and if after a predetermined period of time no product  100  is dispensed, the vending machine will determine that no product is present within the row.  
         [0029]     When the indicator  105  is a magnet, the system of the present invention finds the precise location of the product to be dispensed (so that the product dispenser drive  104  and the drive shaft  28  properly align) by finding the center of the magnetic field of the magnet to properly locate the elevator  102 . The system accomplishes this by first moving to a position of about 0.320″ to the right or left of the expected X/Y coordinates of the selected product. Next, the elevator  102  is moved toward the expected position of the product row. The vending machine records a first position Xa where the sensor  103  first senses the indicator  105 . The elevator  102  continues moving past the indicator  105  until the indicator is no longer sensed. The elevator  102  is then driven in the reverse direction and records the position Xb where the position sensor is activated. The vending machine then calculates the center position of X coordinate of the indicator  105  as Xcenter=Xa+(Xa−Xb)/2. Next, the elevator  102  is moved to a position about 0.5″ below the expected Y coordinate of the indicator and to the Xcenter X coordinate. The elevator  102  is then moved upwardly until the sensor detects the indicator and then an additional 0.160″. At this point, the elevator  102  is located in an acceptable position to extend the product dispenser drive  104  and rotate the drive shaft  28  to vend product. Alternatively, the center of the Y coordinate could be determined in the same manner as the X coordinate. In yet a further alternative variation, the X coordinate could be determined by finding leading edge of the indicator  105  and moving a predetermined distance just as with the Y coordinate above.  
         [0030]     In another method of finding the center of the indicator  105  and referring to  FIGS. 12 and 13 , the elevator  102  is moved to a position below the indicator (Y coordinate) and to the expected X coordinate of the indicator  105 . Next, the elevator  102  is moved vertically across the indicator  105 . Position A and position B are determined by detecting the presence or absence of the indicator as the sensor  103  and elevator  102  move past the indicator  105 . Understanding that the expected X coordinate of the indicator  105  might not be the actual X coordinate of the indicator, the chord joining position A and position B may not pass through the center of the indicator  105 . The elevator  102  now moves to the center point between position A and position B (Y coordinate) and the expected X coordinate of the indicator  105 . Next, the elevator  102  moves to the right or left until the presence of the indicator  105  is no longer detected. This position is then recorded as position C. Provided that the indicator is uniform, the three detected positions A, B, and C will represent three points along the circumference of a circle about the indicator  105 .  
         [0031]     To find the center of the indicator from the three positions detected, the system must find the point of intersection of the perpendicular bisectors of any two chords defined by the three positions. The first step to calculating the center point is to solve the equations for the lines containing segments AC and BC in the form ax+by=c. For each segment, the constants are determined using the following equations 
 
 a   BC   =y   B   −y   C  
 
 b   BC   =x   C   −x   B  
 
 a   AC   =y   A   −y   C  
 
 b   AC   =x   C   −x   A  
 
         [0032]     The next step is to determine the equation for the perpendicular bisector of the lines containing AC and BC. These bisecting lines will contain the line segments EO and DO. The equation of the perpendicular bisector is −bx+ay=d. The constant d is determined by calculating the midpoint of the desired line segment and inserting the value for x and y, as shown below. 
 
 d   DO   =−b   BC (( x   B   +x   C )/2)+ a   BC (( y   B   +y   C )/2) 
 
 d   EO   =−b   AC (( x   A   +x   C )/2)+ a   AC (( y   A   +y   C )/2) 
 
         [0033]     Now that the perpendicular bisectors have been found, the intersection of these two lines is calculated. The three equations below are used to calculate the position of the center point. 
 
 Det=−b   BC   *a   AC   +b   AC   *a   BC  
 
 x   O =( a   AC   *d   DO   −a   BC   *d   EO )/ Det  
 
 y   O =(− b   BC   *d   EO   +b   AC   *d   DO )/ Det  
 
         [0034]     As long as the two lines AC and BC are not parallel, the center point can be determined. Moreover, the center O can be calculated with any three points on the circle, regardless of their position. Thus, in an alternative embodiment, the system could make diagonal passes across the sensor  105  and still calculate the correct center point.  
         [0035]     The preferred means for recording the above positions and calculating the product location is an electric circuit, more preferable an integrated circuit, such as an application specific integrated circuit or ASIC.  
         [0036]     In the present invention, the new coordinates for the indicator  105  may be memorized by the vending machine such that, in the future, the elevator will proceed directly to the new position or, as is preferred, the coordinates are not memorized in any manner and they are redetermined with each product vend cycle. By not memorizing the coordinates, the precise coordinates are always detected and mis-vending of product is avoided. This is particularly useful when the dimensions of the vending machine may have changed, for example, as a result of moving the vending machine or changing the vending machine geometry as a result of changing product weight distribution.  
         [0037]     While the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention.