Abstract:
A dispensing system for a vending machine includes a vend motor, a cradle, a load bar and a push arm. Upon selection of a particular product, the vend motor rotates the cradle, causing the product to emerge from the vending machine. The cradle is designed to accommodate a wide array of container sizes. The dispensing system incorporates a rotation sensor, a position sensor, and a lift arm. The sensors enable accurate rotation of the cradle through a plurality of vend angles depending upon the particular product being vended, while the lift arm cooperates with the push arm and load bar to refill the cradle after a series of product containers have been dispensed. In addition, the vend motor includes a soft start control that prevents instantaneous rotation of the output shaft so as to prolong an overall operational life of the motor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of prior U.S. patent application Ser. No. 10/678,154 filed on Oct. 6, 2003, which claims benefit of 60/415,761 filed on Oct. 4, 2002, and claims benefit of 60/415,767 filed on Oct. 4, 2002, and claims benefit of 60/415,773 filed on Oct. 4, 2002, which issued as U.S. Pat. No. 7,401,710 on Jul. 22, 2008. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to the art of vending machines and, more particularly, to a dispensing system for a vending machine. 
     2. Discussion of the Prior Art 
     Vending machines are commonly utilized in dispensing a wide range of products, including canned and bottled beverages, edible food items, and other consumer products. In the case of dispensing beverage products, it is desirable to configure a vending machine such that it is capable of dispensing various different sized and configured beverage containers. That is, as manufacturers of beverage products alter their container designs, it is desirable to not require the vending machine itself to be reconfigured, at least substantially, to accommodate a new product. Of course, the reliability of the overall dispensing system of the vending machine must be maintained. 
     For use in connection with dispensing canned and bottled beverage products, there is typically employed either a vend rotor or oscillator which is driven by a vend motor to sequentially dispense the beverage containers. In the case of the rotor, this arrangement generally takes the form of a cradle which initially receives one or more of the beverage products to be dispensed. Such cradles are typically semi-cylindrical in shape and mounted for rotation about a fore-to-aft extending axis under a column or stack of stored products. As the cradle rotates, the product(s) carried therein is dispensed. Typically, the cradle will be compartmentalized such that two or more fore-to-aft spaced products can be supported at any given time, with each product being sequentially dropped from the cradle as the cradle performs a complete 360° rotation, whereupon the cradle receives one or more additional products for dispensing. Known oscillator-type dispensing arrangements work on a generally similar principal, except that the corresponding product support or retention structure is driven to oscillate back and forth through a predetermined angle for dispensing sequential containers from a stack. 
     Therefore, in connection with these conventional can and bottle vending machines, motors are employed to establish the required rotation or oscillation which, in turn, functions to release stored products from within a storage rack. Whether the motor is coupled to a rotating (rotor) or oscillating (oscillator or bale) vending device, the overall system design must be configured to accommodate the particular product parameters. To this end, vendors typically employ a variety of shims, bottle rods, rod sleeves or the like to adjust the vending geometry as needed. Obviously, requiring these additional components to provide vending flexibility is undesirable, costly to manufacture, and increases overall assembly time. 
     In order to establish the desired rotation or oscillation, vending machines also utilize the various motors to move mechanisms in the form of cams and the like. In turn, the mechanisms release stored product from within a stack or storage rack arranged within the vending machine. In order to properly execute a vending operation each and every time a selection is made, motor shaft position must be controlled. In general, prior art vending machines typically use either AC or DC motors mounted to a plate within the vending machine. The motors are coupled to a cam and switch system which, in turn, controls the position of either the rotating or oscillating bail vending device. Furthermore, the vend motor must include an anti-pilferage mechanism as required to meet UL standards. 
     In operation, the cams and switches, when actuated by the motor, operate the rotating or oscillating bail device to dispense a product. Once the product vends, the cam interrupts power to the motor. Alternatively, the cam might interrupt power to a controller which, in turn, interrupts power to the motor. In any event, through a rather complicated arrangement of cams, switches and associated linkages, once a vending operation is complete, power to the motor is interrupted. In this manner, pilferage from the machine is limited. 
     Certainly these systems have proven themselves effective over the years, however, the overall complexity of the mechanisms has resulted in numerous failures. Cam mechanisms wear, switches fail, and bottles and cans jam in the stacks. Vending machines require constant maintenance in order to ensure the proper vending of product. Naturally, in order to remain profitable, the maintenance costs are passed on to the consumer through elevated prices of the vended product. 
     Still another concern is wear and tear on vend motor components. In typical fashion, upon receipt of an electrical signal, the vend motor activates instantaneously. That is, the output shaft moves from a state of rest to a dynamic state almost immediately. This abrupt change in state places a great deal of stress on gears, shafts and other components in the drive train. Over time, these stresses will cause a failure in the vending operation. 
     Based on the above, there exists a need in the art for an improved product delivery system for a vending machine which is designed to flexibly accommodate future package configurations, such as the length and/or diameter of various beverage containers, without requiring an undue number of components. In addition, there exists a need to more accurately control a vend motor by simplifying the overall cam and/or switch arrangement. Furthermore, there exists a need to operate a dispensing system in a manner so as to minimize stresses on motor components. In general, there exists a need to enhance the versatility and reliability of a vending machine dispensing assembly. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a dispensing system for a vending machine. In accordance with the most preferred form of the invention, the dispensing system includes a vend motor, a notched rotor, a push arm member, a return spring and a load bar. The vend motor is carried by a motor housing attached to support structure of the vending machine. An output of the vend motor is utilized to rotate an output cam member which, in turn, drives the notched rotor. The push arm member includes a first end portion rotatably mounted to a boss provided as part of the motor housing, while a second end portion of the push arm member is positioned along a peripheral portion of the output cam. In this fashion, as the cam rotates, the push arm member glides along the peripheral portion. The push arm is also connected to the load bar, retained by the return spring, and pivoted when engaged by a projection or lifting arm provided about a portion of the output cam. 
     With this arrangement, the vend motor functions to rotate the rotor to a series of controlled, dispensing positions. These positions actually correspond to spacing required in connection with properly dispensing a given product. In a hold position, the rotor is positioned to prevent pilferage. The notches provided as part of the rotor establish the vending geometry required for a wide variety of packages, without the need for additional components such as shims, bottle rods and the like. The rotor can actually be configured to any combination of notch length, depth and quantity to vend a variety of products. Therefore, a single rotor configuration will accommodate an abundance of present and future package designs. A corresponding arrangement can be established employing an oscillator. 
     In accordance with one embodiment of the present invention, the vend motor includes a main body housing, a DC motor, a plurality of sensors, an electronic controller, e.g., a I/O control board, and an actuating member. Each motor assembly is mounted to internal structure of the vending machine below an associated bottle stack. In the preferred form of the invention, each respective motor assembly is interconnected to a main, programmable controller which functions to operate a particular vend motor based on a consumer selection. 
     Specifically, a 24-volt DC motor having an input shaft and an output shaft is mounted to a top portion of the main body housing. More specifically, the output shaft is connected to a rotator or oscillator device through a gear system contained in the main body housing. Preferably, an input shaft rotation sensor is secured to the motor assembly and positioned to measure the angular rotation of the input shaft. In addition to the rotation sensor, a position sensor is mounted to the motor housing and positioned to measure the angular position of the output shaft. Preferably, the rotation and position sensors constitute magnetic sensor devices. However, other sensors, e.g., optical, hall-effect, detent and the like, are acceptable. Preferably, the position sensor is accurate to within ⅓° of rotation. 
     In accordance with the present invention, each of the rotation and position sensors interconnect with the electronic controller mounted to the motor housing. In this manner, a main controller can operate the vend motor to efficiently accomplish a desired vending operation. By mounting the sensors and motor to a housing having a profile which fits within the profile of the DC motor, a compact vending motor package is created which improves product delivery efficiency. With this overall arrangement, the combination of the input and output sensors and the electronic controller allow for very accurate, programmed motor position control preferably to within ⅓° of shaft rotation. In this preferred form of the invention, the sensors and controller eliminate the need for position sensing cams and switches and simplify the overall wiring of the machine. Additionally, through simple programming of the main controller, the rotator or oscillator vend position can be adjusted so as to eliminate the need for shims, bottle rods, and bottle rod sleeves. 
     In further accordance with the present invention, use of the 24-volt DC motor enables bi-directional movement of the rotator or oscillator device. With this arrangement, by simply controlling the polarity of power supplied to the motor, forward and reverse operation of the output shaft is possible. Accordingly, once the vending operation is complete, the motor output shaft can be reversed or backed-up to a “hold” position which prevents pilferage from the machine. In this manner, the DC vend motor of the present invention meets the requirements established by Underwriter&#39;s Laboratories. 
     In accordance with another aspect of the present invention, the dispensing system includes a soft start control. The soft start control utilizes a memory module in which is stored a software program for generating a start signal for the vend motor. The software program creates a dynamic pulse width modulated (PWM) signal for starting the motor. Preferably, the program&#39;s PWM signal starts with a low pulse width ratio that doubles with each successive pulse until a 100% duty cycle is achieved. In this manner, current is gradually applied to the motor such that the transition from a state of rest to a dynamic state is buffered. With this arrangement, the gears, shafts and other drive components will realize extended operational life. 
     The PWM signal of the present invention can easily be varied through manipulation of the software code such that a wide range of frequencies can be achieved. In this fashion, a particular PWM train can be implemented for each motor type, or design requirement. Further in accordance with the present invention, the soft start control is designed to be a “start and forget” system. Accordingly, once a 100% duty cycle is achieved, the software program terminates. In this manner, additional monitoring and termination of the signal is no longer required. 
     Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a vending machine, shown having a main door in an open position exposing internal structure of the machine to illustrate interior vending zones, incorporating the vending machine dispensing system of the invention; 
         FIG. 2  is an exploded view of the dispensing system of the invention; 
         FIG. 3  is an upper perspective view into the vending machine of  FIG. 1 , further showing the dispensing system of the invention; 
         FIG. 4  is a partial, front plan view of the vending machine of  FIG. 1 , with one vend motor removed to illustrate a push arm arrangement constructed in accordance with the present invention; and 
         FIG. 5  is a perspective view of a vend motor assembly depicting rotation and position sensors arranged in accordance with the present invention, along with a block diagram depicting a soft start system employed in connection with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With initial reference to  FIG. 1 , a vending machine  2  includes a cabinet frame  4  having top, bottom, side and rear walls  6 - 10  that collectively define a central cavity  14 . In a manner known in the art, a first pair of wheels or casters  16  and  17  are secured to a front edge portion of bottom wall  7  to facilitate the positioning of vending machine  2 . Of course it should be realized that a second pair of wheels (not shown) are also arranged on a rear portion of bottom wall  7 . A door  18  is pivotally mounted to cabinet frame  4  to selectively enable access to central cavity  14  in order to load various product containers or other commodities into vending machine  2 . Door  18  is provided with a locking mechanism, shown in the form of a threaded rod  19 , to retain door  18  in a closed position so as to prevent pilfering of the commodities from central cavity  14 . Door  18  is also provided with an opening  20  to enable a consumer to remove a vended product container or other commodity from vending machine  2 . 
     Central cavity  14  includes a storage section  21 , a dispensing section  22 , a delivery section  24  and a lower section  26 . Storage section  21  is provided to hold products in escrow until a vending operation is performed. Towards that end, storage section  21  is provided with a plurality of vertically extending column walls  32 - 36  which, together with side walls  8  and  9 , form a plurality of column or stack areas  40 - 45 . In the embodiment shown in  FIG. 1 , stack areas  40 - 45  constitute single stack columns. However, it should be understood that the present invention also encompasses vending machines having multi-stack columns. In any event, stack areas  40 - 45  are partitioned by walls  32 - 36  to contain, separate and support a plurality of generally cylindrical containers  49  which, in the embodiment shown, constitute soda cans. 
     As further shown in  FIG. 1 , dispensing section  22  is provided with a frontal support wall  60  having arranged thereon a plurality of vend motor units, one of which is indicated at  65 . As will be discussed more fully below, a plurality of cradles (not shown), that support and deliver product container  49  to a consumer, are arranged behind frontal support wall  60 . Actually, each column or stack area  40 - 45  is provided with an associated cradle (not shown) that is operated through a respective one of the plurality of vend motor unit  65 . Upon selection of a particular product container  49  or other commodity, one of the plurality of vend motor unit  65  is activated to rotate a respective cradle causing a product container  49 , corresponding to the selected product to emerge from vending machine  2 . That is, product container  49  is transported to a product delivery chute  70  provided in delivery section  24  which is exposed to opening  20  in door  18 . In order to maintain containers  49  in a refrigerated state, lower section  26  is provided with a cooling system  75 . In general, the above description is provided for the sake of completeness and to enable a better understanding of the invention. The present invention is particularly directed to a vending system for delivering a product from stack areas  40 - 45  to product delivery chute  70 . 
     Referring to  FIGS. 2-5 , a vending system constructed in accordance with a preferred embodiment of the invention is indicated generally at  100 . As each stack area  40 - 45  includes a distinct vending system  100 , the vending system  100  for column area  44  will be described in detail and it is to be understood that each of stack areas  40 - 43  and  45  has a corresponding vending system  100 . As shown, vending system  100  includes vend motor unit  65 , a notched cradle  106 , a load bar  108 , a push arm  110  and a return spring  112 . Cradle  106  and load bar  108  extend fore-to-aft in a bottom portion of column area  44 . In accordance with a preferred form of the invention, vend motor unit  65 , push arm  110  and return spring  112  are actually mounted on an outside surface of frontal support wall  60  and, as will be discussed more fully below, are operatively connected to cradle  106  and load bar  108 . 
     In accordance with the depicted embodiment of the present invention, the overall vend motor unit  65  includes a motor housing  120  that supports a motor  122 . Preferably, motor  122  is a 24-volt DC electric motor having an output shaft  124  interconnected to a vend motor unit output shaft  125  through a gear mechanism (not shown). More specifically, vend motor unit output shaft  125  includes a first hub portion  128  having a cam surface  130  provided with a lifting arm  131 . Vend motor unit output shaft  125  also includes a second hub portion  134  that projects from first hub portion  128 . When mounted to frontal support wall  60 , second hub portion  134  projects through an opening  136  having a bushing  137 . Bushing  137  limits the wear on hub  134  as motor  122  rotates vend motor unit output shaft  125  through various vend positions. As shown, second hub portion  134  includes a plurality of lands and grooves (not separately labeled) which, as will be discussed more fully below, operatively engage with cradle  106  through opening  136 . 
     As best shown in  FIG. 5 , vending system  100  includes a motor shaft rotation sensor  140  and a motor shaft position sensor  142 , each of which is electrically connected to an I/O controller  144 . Preferably, I/O controller  144  includes a memory module  145  for storing particular positions of output shaft  124  and vend motor unit output shaft  125 . Rotation sensor  140  and position sensor  144  can be of various types, such as Hall effect sensors, magnetic sensors as well as other non-mechanical sensors, that provide very accurate inputs to I/O controller  144 . With this particular arrangement, the position of vend motor unit output shaft  125  can be controlled in a very precise manner. That is, I/O controller  144  can determine, within approximately ⅓ of a degree of rotation, a particular position of vend motor unit output shaft  125 . Motor housing  120  is also provided with a terminal block element  150  which electrically interconnects vend motor unit  65  with a main vend control  152  through a wire harness  153 . As also illustrated in  FIG. 5 , a plurality of spacers  155 - 157  are arranged about motor housing  120 . As will be discussed more fully below, spacers  155  and  157  orient vend motor unit  65  with respect to frontal support wall  60 , as well as the remainder of the components of vending system  100 . 
     Referring to  FIG. 2 , cradle  106  includes a first end  167  provided with a hub portion  168  having a plurality of lands and grooves (not separately labeled) that are adapted to engage with second hub portion  134  of vend motor unit  65 . First end  167  leads to a second end  170  through an intermediate portion  172 . Preferably, intermediate portion  172  includes a plurality of terraced notches or grooves, one of which is indicated at  176 . Cradle  106  is adapted to support a plurality of containers at a position adjacent to each of the plurality of notches  176 . During a vend operation when cradle  106  is rotated through various vend angles, a product(s) resting in intermediate portion  172  will be sequentially dispensed from vending machine  2 . The particular programming of the vend angles into controller  140  does not form part of the present invention and is actually set forth in greater detail in a U.S. patent application entitled “Microprocessor Programmable and Selectable Vending Options and Control” which is filed on even date herewith and incorporated herein by reference. 
     As further illustrated in  FIG. 2 , load bar  108  includes a first end  186 , a second end  187 , and an intermediate portion  188 . More specifically, first end  186  is provided with a forward guide member  190  adapted to extend through an opening  191  in frontal support wall  60  (see  FIG. 4 ). Also arranged on first end  186  is a pivot member  192  which is supported for rotation in a bushing  193  on frontal support wall  60 . In a similar manner, second end  187  is provided with a rear guide member  194  adapted to travel in a rear guide track  195  (also see  FIG. 3 ) arranged in rear wall  10 . Adjacent to rear guide member  194  is a rear pivot member  196  which is rotatably supported by rear wall  10  and axially aligned with forward pivot member  192  to define an axis of rotation for load bar  108 . 
     During select portions of a vend operation, load bar  108  is moved between a first position wherein intermediate portion  188  supports a column of product containers, to a second position enabling a lowermost container(s) to be carried into cradle  106 . Toward that end, push arm  110  is provided with a first end  202  having a hub  203  adapted to matingly engage with guide member  190  of load bar  108 . First end  202  of push arm  110  is also provided with an ear element  204  having a central opening (not separately labeled) for connecting with return spring  112 . First end  202  leads to a second end  206  adapted to ride along cam surface  130  of first hub portion  128  during the vend operation. In addition, second end  206  is provided with a guide element  208  adapted to travel in a guide opening  210  located in frontal support wall  60 . With this construction, rotation of vend motor unit output shaft  125  will cause lifting arm  131  to engage with second end  206  of push arm  110 . Lifting arm  131  causes push arm  110  to translate upward, moving load bar  108  from a first or support position to a second or loading position, thus enabling product containers  49  to fall into cradle  106 . As lifting arm  131  continues to translate upward, guide element  208  travels within guide opening  210 , whereupon push arm  110  will eventually return to an initial set position under the force of return spring  112 . 
     The manner in which vending system  100  carries out a vend operation will now be described. In a manner known in the art, to initiate the vend operation, a consumer inserts currency into a designated opening provided on vending machine  2 . At this point, the consumer selects one of a plurality of products through various control elements (not shown) generally arranged on an outer surface of door  18 . After product selection, main control  152  signals the I/O controller  144  to activate a vend motor unit  65  corresponding to a particular stack area  40 - 45  in which the selected product is located. Actuation of vend motor unit  65  causes vend motor unit output shaft  125  to begin to rotate cradle  106  to a particular vend angle. Following each vend operation, controller  144  stores an angle value or position corresponding to a previously vended product. I/O controller  144  will rotate cradle  106  a predetermined amount in order to cause the selected product container to fall passed the associated one of the plurality of grooves  176  into product delivery chute  70 . After a predetermined number of vending operations, generally corresponding to the storage capacity of cradle  106 , lift arm  131  causes push arm  110  to travel within opening  191 , causing load bar  108  to deflect or move to its second position in order to allow additional product containers  49  to be replenished or reloaded in cradle  106 . During the entire operation, I/O controller  144  senses, through inputs received from rotation sensor  140  and position sensor  142 , the rotational angle of cradle  106 . 
     In accordance with the most preferred form of the present invention, I/O controller  144  supplies motor  122  with a pulse width modulated (PWM) signal to control a speed at which vend motor unit output shaft  125  rotates. I/O controller  144  includes a program, stored in memory  145 , for generating a particular start signal for vend motor unit  65 . That is, a ramped PWM signal is sent to motor  122  so as to gradually increase the rotational speed of vend motor unit  65 . Preferably, the PWM signal starts with a low pulse width ratio that doubles with each successive pulse until a 100% duty-cycle is attained. In this manner, electrical current is gradually applied to motor  122  such that a transition from a state of rest to a dynamic state is buffered. The PWM signal of the present invention can be easily varied, such as through a manipulation of software code, such that a wide range of frequencies can be achieved. In this manner, a particular PWM train can be developed for each application. In further accordance with the present invention, the soft start control is designed to be a “start and forget” system. That is, once initiated, additional monitoring is not required. With this construction, rapid starts and stops that typically wear motor components are eliminated. In further accordance with the most preferred form of the invention, I/O controller  144 , rotation sensor  140  and position sensor  142  are all carried by motor housing  120  and arranged in a manner to maintain a thin profile for vend motor unit  65 . 
     In any event, it should be recognized that the vending system of the present invention provides an accurate product dispensing control, preferably to within approximately ⅓° of rotation, thereby eliminating the need for mechanical position sensing components. Moreover, by incorporating the controller and various sensors into vend motor unit  65 , the overall wiring of vending machine  2  is simplified. The vending system also eliminates the need for shims or bottle rods to adjust for various product container sizes. Furthermore, vend motor unit  65  prevents pilfering from vending machine  2  as required by U.L. standards. 
     Although described with reference to a preferred embodiment of the present invention, it should be readily apparent to one of ordinary skill in the art that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, it should be recognized that the cradle could be in the form of an oscillator or rotor and that various cradles could be used to accommodate different product container sizes. Also, it should be noted that the vend motor can be made operable in both forward and reverse rotational directions. Most preferably, after a vend operation, the vend motor is partially reversed so as to prevent unauthorized removal or pilfering of product containers from the vending machine. In any event, the invention is only intended to be limited to the scope of the following claims.