PATENT DOCUMENT

Abstract:
This invention is a vending machine and components parts that include a sophisticated positioning system, gripper and trays for improved efficiency in product retrieval and delivery. A unique initialization and calibration system is implemented at start up to determine the positions of shelves and trays of product containers in the machine, and may be implemented at other times if trays or shelves are added or removed, or if tray or shelf positions change. These positions are then used by the positioning and gripping systems to accurately and efficiently retrieve products from the trays. Related methods are also disclosed.

Full Description:
This application claims the benefit of U.S. application Ser. No. 11/066,775 filed on Feb. 25, 2005 now U.S. Pat. No. 7,451,891, which claims the benefit of U.S. Provisional Application No. 60/548,321 filed on Feb. 27, 2004, all of which are incorporated herein by this reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is a vending machine that is capable of efficiently storing, retrieving and delivering product containers having a variety different sizes, shapes and weights. In particular, the vending machine of the present invention may be simultaneously stocked with products in containers of different sizes, shapes and/or weights, and efficiently store, retrieve and deliver each of those containers. 
     2. Description of Related Art 
     Changes and improvements in product container configurations have led to increased performance demands upon vending machines. In the past, a given vending machine was generally relegated to the delivery of a single type of product container of uniform dimension and/or shape—only bottled beverages, only canned beverages, only beverages in cartons, and so on. Such vending machines could not simultaneously store, retrieve or deliver containers having different sizes, shapes or weights. While some improvements have allowed certain vending machines to handle multiple containers (e.g., a single machine may be adapted to handle beverages in both aluminum cans and plastic bottles), these machines require the containers to have similar characteristics, i.e., all of them having a generally cylindrical body. Other machines require special kits to adapt them to be able to handle different sizes and shapes of containers, including cylindrical packages of different sizes. 
     The ever-increasing number of different container configurations necessitates the development of a single vending machine that can store, retrieve and deliver substantially different product packages quickly and smoothly. For example, beverages are not only provided in aluminum cans, and glass or plastic bottles, but also in rectangular cartons (such as milk cartons), hourglass-shaped containers, and flexible mylar or foil containers (such as children&#39;s juice packages), to name a few. One need only imagine the many different children&#39;s characters whose shapes may be adapted into beverage containers to appreciate the challenge to the vending machine industry presented by such containers. In addition, manufacturers are regularly developing new sizes and shapes for beverage containers and other packages for advertising or other reasons, all of which pose new problems for the storage, retrieval and delivery of those different containers by a single vending machine. 
     Various devices have been developed to allow vending machines to store, retrieve and deliver packages having different characteristics. For example, U.S. Pat. Nos. 6,230,930 and 6,328,180 disclose devices for transporting a carriage along the X and Y planes of a vending machine to an appropriate location for retrieving a selected product. An escapement mechanism is used to release the endmost product from a queue into the carriage which then gently transports the product to a delivery port. However, both of these devices are limited to use with generally cylindrical beverage containers. U.S. Pat. No. 6,499,627 discloses a vending machine using conveyor belts to transport beverage containers. U.S. Pat. No. 5,467,892 discloses a vending machine for retrieving standardized containers containing different articles from a shelf-like structure, making the containers accessible by a customer for removal of the article inside, and returning the empty container to the shelf. However, neither of these devices is capable of transporting containers of different sizes, shapes, weights and/or deformabilities. 
     Existing vending machine escapement mechanisms generally trap the next-to-vend product in position at the end of the tray column, using a mechanical stop, which pins this product against the opposing column wall or some other rigid element while the endmost product is removed. This principle requires accurate gauging of the width of the package in order to guarantee retention of the next-to-vend package. Due to the proliferation of package sizes, carbonation levels (which determine package firmness and thus dimensional stability), and package types (cans, glass bottles, plastic bottles, deformable mylar squeeze packs, cartons, etc), most existing machines are unable to deal with more than one type of package, and can only reliably deal with containers having rigid, uniform exteriors. It is therefore desirable to provide a vending machine that is capable of simultaneously storing containers having a wide variety of different sizes, shapes, deformabilities and/or weights, and efficiently retrieving and/or delivering such containers. 
     Product freshness is a perpetual problem for vending machines. Vending machines should be stocked and re-stocked so that the oldest products are vended before the newer products, in a “first in first out” manner. Many vending machines utilize racks or shelves extending from the back end of the machine to the front, with products retrieved and vended from the front end. Unfortunately, the front end of the rack or shelf is also the easiest, and in some cases it is the only way to access when restocking the vending machine. Such racks require all existing products to be removed in order to restock with newer, fresher products in front. This may result in a tendency to deposit newer products at the easily-accessible front end of the rack or shelf, thereby pushing the older products to the rear. This can result in the older products remaining in the vending machine for great lengths of time, leading to potential spoliation and consumer dissatisfaction. It is therefore desirable to provide a vending machine having front-facing racks or shelves that can be easily restocked from their rear ends forward. 
     Repair and maintenance of vending machines in the field is also an ever present problem. Revenue may be lost if the machine must be disassembled for any length of time while critical component parts are repaired in the field. With more complicated machines, repairs become more difficult and time-consuming. Removing the machine for factory repair completely eliminates revenue generation. It is therefore desirable to provide the various component parts of the machine (product trays, shelves, product retrieval mechanism, electronic components, delivery port, heating/cooling system, etc.) in modular form so that if any of these components fail in the field, they may be easily swapped out with working components in a minimal amount of time. 
     SUMMARY OF THE INVENTION 
     The present invention is a vending machine including combinations of component parts and unique methods that is capable of storing, retrieving and delivering product containers having a wide variety of different sizes, shapes and/or weights. The machine, components and methods of the present invention allow the vended products to be varied in location and number with relative ease, allow for easy restocking of products in such a manner that the older products are vended before the newer ones, and allow minimum down time for maintenance and repair. 
     The machine, components and methods of the present invention are directed toward a vending machine of a type having sets of trays or queues that extend from the back of the machine to the front so that the products in the queues are visible to purchasers through a transparent panel or window at the front of the machine. The invention employs an X-Y-Z positioning system for moving a product carriage into position adjacent to a selected queue, and a unique mechanized gripping device that works in conjunction with uniquely designed queue trays for retrieving any of wide variety of containers of different sizes, shapes and/or weights from the queue. The product is retrieved from the selected queue and transported to a delivery location where it is made available to the purchaser. 
     The configuration of the positioning system including its motorized methods and assemblies allows for quick and efficient product retrieval. The system positions a gripping mechanism by a substantially direct route from a rest position to the selected queue, and provides for quick, affirmative gripping of the product rather than reliance on gravity to feed the product into an awaiting transport mechanism. The flexibility of the invention allows it to be used with a wide variety of different container designs, shapes and sizes without any need to convert or alter the product trays, as would be required in existing equipment which employ an escapement-type release mechanism at the end of each tray queue. 
     The trays used in the present invention may be oriented from the back to the front of the machine and in combination with a glass panel in the door provide for visual product selection which allows for greater flexibility in changing products because selection is controlled by location only. In systems not having visual selection capability, each product selection mechanism must be correlated with a particular queue within the vending machine. Such machines also require a label or product identification to match the selection mechanism with the appropriate product queue. 
     All of the refrigeration components of the present invention may be combined into a self-contained easily accessible modular unit for quick and simple repair/replacement and maintenance. 
     One of the most important aspects of the present invention is a unique gripping mechanism that can reliably remove any of a wide variety of containers of different sizes, shapes and/or weights, including such deformable containers as children&#39;s juice pouches, from the endmost position in a queue. The gripping mechanism generally includes a plurality of opposing movable fingers that operate independently of each other, and are capable of moving between open and closed positions. The independent movement of these fingers allows them to engage a container at different places and close around the container for a secure grip. The gripping mechanism also includes a pair of lower opposing fixed-position fingers that are used to temporarily move out of the way a set of movable gates located at the end of a tray holding a queue of containers. The movable fingers of the gripping assembly are positioned so that, when closed against a container, they exert a force against the container at different locations upon the container surface. The position of the fingers, their compressive force, and the friction associated with such force, provide the mechanism with a firm “grip” upon the container. This allows the gripping mechanism to lift, hold, transport and release product containers of different sizes, shapes, weights, rigidity, dimensional stability and/or deformability. 
     In alternative embodiments, the gripping mechanism may employ an open sleeve having a C-shaped cross section wherein the container enters through the open end of the sleeve which is then closed or compressed around the container. Alternatively, the fingers of the gripping mechanism may be flat, flexible, jointed or articulating. They may be straight or have an arcuate cross section. The gripper may also be provided with one or more movable lower fingers that fit under and lift the container from the bottom (instead of, or in addition to the side fingers). In another embodiment, one or more of the side fingers may be equipped with an inflatable member that is expanded to engage a product container, and deflated to release it. 
     Another important aspect of the present invention is a unique tray structure for dispensing products that works in conjunction with the gripping mechanism to allow the endmost container to be removed from the queue of the tray, while preventing the next-to-vend container from also being removed. A typical tray includes a pair of parallel queues having a downward slope from the back to the front of the vending machine, and pressure imparting members that urge products toward the front of the tray. A pivotally mounted movable gate is provided at the front end of each queue, mounted to one of the sidewalls of the queues. Alternatively, pairs of gates may be provided on both sides of any single queue. The gates may pivot in the X-Y plane (up and down) or in the Z plane (in and out) with a stop to prevent a product container from pushing such Z gates open. An optional movable central piece or arm may be provided at the front of each dual tray between the two queues. A flange or rib may be provided at the bottom of the front of each queue of the tray. The flanges and gates prevent products from exiting the front of the tray until the gripping mechanism arrives. Upon arrival (using the X-Y-Z positioning system described below), the fixed-position fingers of the gripping mechanism first move the gate(s) and the optional central piece out of the way with a downward motion. Then the movable fingers engage the foremost container in the queue. The gripping mechanism then raises the container over the lower flange of the queue, if necessary, and then withdraws it from the queue (in the Z direction). The withdrawal action causes the gate(s) and optional central piece to move back into place preventing the next-in-line product from exiting the queue. 
     A simple tray embodiment may include a single tray column and queue, and a single pivotally mounted gate at the front. 
     Another embodiment of a product storage tray includes: (a) a tray body comprising a floor, two longitudinal side walls extending substantially the length of the floor substantially parallel to each other, and a center wall spaced substantially equidistant between the sidewalls and extending substantially the length of the floor thereby forming adjacent columns permitting two queues of product to be held side-by-side; (b) a tray front piece with a floor, side walls and a center wall which align with the floor, side walls and center wall of the tray body thereby forming an extension of the tray body in the longitudinal direction and at least one stop wall extending into the column from the tray front piece at the floor for preventing the vended products from sliding out of the front of the column; (c) a gate piece pivotally attached to each side wall of the front piece and extending in a generally horizontal direction from each side wall of the front piece in the direction of the column adjacent to each front piece side wall; and (d) a divider piece pivotally mounted to the center wall of said front piece and extending in a generally horizontal direction from the center wall toward the front of the tray in alignment with the center wall of the tray. 
     It is to be appreciated that in some instances, products to be vended may be provided in containers having minimal spatial depth. In order to compensate for such thin products (e.g., a deck of cards), the distance traveled by the gripper mechanism in the Z-direction may be modified. In this way, the gripper only travels in the Z direction far enough to grasp the endmost product, instead of traveling too far and retrieving more than one product from the selected queue. 
     Yet another important aspect of the present invention is a unique X-Y-Z positioning system that is capable of moving a carriage so as to be precisely aligned with a selected product queue. A typical X-Y positioning system of the present invention includes (a) a pair of Y-rail assemblies mounted in the door or storage cavity of the vending machine in a generally vertical orientation; (b) an X-rail assembly deployed in a generally horizontal orientation (perpendicular to the Y rails) operatively mounted at each end to a Y-rail assembly for movement along the Y-rail assemblies; (c) a first motor assembly for controlling movement of the X-rail assembly along the Y-rail assemblies; (d) a carriage operatively mounted to the X-rail assembly for movement along the X-rail assembly; and (e) a second motor assembly for controlling movement of the carriage along the X-rail assembly. 
     The carriage is designed to support a device for removing products from queues within the vending machine. Such a device may be the gripper mechanism described previously. Such a mechanism may be provided in an extendable housing on the carriage that may be moved in and out along the Z-axis so as to allow the gripper to remove the endmost product from the selected queue. 
     Another unique aspect of the invention is the delivery port assembly that provides customer access to vended products delivered from inside storage cavity the vending machine. Upon product selection, the vended product is retrieved and transported to the delivery port assembly where it is dropped into a chute leading to a delivery bucket. The chute is pivotally attached to a panel adjacent to the delivery bucket and serves as an opening to the delivery bucket to receive product dropped from the inside of the storage cavity. The product slides down the delivery chute into the delivery bucket whereupon said delivery chute pivots closed, causing the product container to be tilted upright and closing the opening between the storage cavity and the delivery port assembly. This closure prevents unauthorized access to the storage cavity through the delivery port. When the delivery bucket is pivoted forward it tilts open at an outward angle away from the door exposing a vended container to the customer for retrieval. 
     Another unique aspect of the present invention is its modular design in which several of the components of the machine may be easily swapped out for repair or replacement including the gripper mechanism, the X-rail, the Y-rails, the carriage, trays, shelves, delivery chute and bucket, and climate control system. The interior cabinet of the vending machine is divided into two chambers. A larger upper chamber is provided for holding the queues of beverage containers, and the container retrieval system. A smaller lower chamber is provided for holding the climate control apparatus which could be a heater or a cooler. All of the necessary climate control components are built into a compact modular unit that can be easily removed from the lower chamber. Opening the door of the vending machine allows access to both chambers. In the event of a failure of any part of the climate control apparatus, the modular unit may be removed and replaced with another functional unit so as to minimize down time of the vending machine. The defective unit may then be discarded or repaired at another location so that it can later be installed into the same or a different vending machine. Meanwhile, the newly installed modular unit allows the affected machine to continue uninterrupted operation. 
     The invention further contemplates that identical detectable elements such as reflective optical patches are provided on the front of each tray, and that a corresponding sensing element (e.g. an optical sensor) is provided in conjunction with the gripping mechanism to permit the system to determine the then current tray orientation. A startup sequence is performed following power up, and as part of the sequence the carriage first traverses along Y axis at one side of the machine allowing the gripping mechanism housing to detect the presence of a tray on each shelf along that side through use of the sensing element. This sequence finds the location of one side of each shelf. For each shelf identified, the startup sequence may also cause the carriage to traverse along the Y axis on the opposite side of the machine, again using the sensor on the gripping mechanism housing to detect the presence of a tray on each shelf along that side. The locations of the opposite sides of each shelf are then compared to each other to determine whether there is any variation in the shelf position from horizontal. Any such variation is calculated, as are the intermediate tray locations on every shelf, so that the gripping mechanism is taken to the proper location when any of the tray queues are selected. 
     If the door is left open for a predetermined interval (e.g. 10 minutes) that is long enough for the user to have changed the positions of the shelves, this sequence is performed again to confirm the positions of the shelves. In those cases where the locations have changed, the new shelf configuration and location data is updated. 
     It is to be appreciated that each of the above described aspects of the present invention may be implemented separately or in different groupings or combinations, according to the needs of the user and the capabilities of the vending machine. 
     Thus, an all-inclusive version of the invention provides for a machine, components and methods for vending products in containers that includes: (a) a cabinet with a door cooperatively forming an internal storage cavity which is further divided into an upper compartment and a lower compartment by an internal floor within the storage cavity; the door including a delivery port assembly for delivery of the product to the customer; (b) a plurality of removable and adjustable trays to hold product containers to be vended sloping generally downward from the rear of the storage cavity toward the front, each tray comprising a pair of parallel columns and pressure imparting members that urge the products in each column toward the front of the columns; (c) a self-contained modular climate control unit including the components needed to provide refrigeration or heating, the self-contained modular unit located in the lower compartment of the cabinet; (d) a product selector mechanism for product selection by a customer which provides an electrical signal initiating the vending process; (e) an X-Y positioning mechanism movable in the storage cavity and mounted adjacent to the front of the storage cavity (or in the door) comprising two Y-rail assemblies oriented in a generally vertical direction, and an X-rail assembly oriented in a generally horizontal direction and operatively connected at each end to a Y-rail assembly, with the X-rail assembly movable in the Y plane along the Y-rail assemblies; (f) a housing for a gripping mechanism mounted on the X-rail assembly and movable in the X plane along the X-rail assembly; (g) a gripping mechanism mounted in the housing and movable substantially horizontally in the Z plane, extendible to the end of a queue of containers for removing the endmost container from the queue, the gripping mechanism having oppositely positioned movable fingers or the like that operate independently of each other, and a pair of fixed position fingers at the bottom of the assembly; and (h) a delivery port in the door of the machine including a chute for receiving a container dropped from the gripping mechanism, the chute leading to a hopper for delivery to a customer. 
     In another aspect of the invention, there is an X-Y-Z positioning mechanism for retrieval and delivery of products for a vending machine of the type having a cabinet and a door cooperatively forming a storage cavity, a product support assembly mounted in the storage cavity and configured to hold a plurality of products to be vended in separate ordered queues, and a delivery port for retrieval by a customer of a vended product. 
     Another aspect of the invention discloses a product storage tray for storage of products to be vended for a vending machine of the type having a cabinet and a door cooperatively forming a storage cavity; a delivery port assembly for customer retrieval of vended products; a product selector mechanism operable by a customer to select a vended product; and a positioning mechanism operable in the X-Y-Z planes which upon product selection retrieves the vended product, transports it to and drops it into the delivery port assembly. 
     Another aspect of the invention provides for a method for removing products from the ends of queues within a vending machine including the steps of: providing queues of variably sized product containers on trays that slope downward from back to front, each queue having at least one movable gate at the front end; positioning a product removal mechanism in front of a selected queue; extending the product removal mechanism toward the selected queue in such a way that is opens the gate(s) to give access to the foremost product in the queue; gripping the foremost product from the queue using a plurality of closable fingers in the removal mechanism; retracting the removal mechanism and the gripped product; moving the product to a delivery port; and releasing the product from the removal mechanism into the delivery port for retrieval by a customer. 
     A more complete method includes the steps of (a) storing a plurality of product containers in a vending machine comprising a cabinet with a door cooperatively forming an internal storage cavity in which the products to be vended are maintained in columnar trays comprising one or more adjacent longitudinal columns, the trays being oriented with the columns declining from the rear of the cavity toward the front of the cavity; the door including a delivery port assembly for delivery of the product to the customer; (b) initiating the vending process upon selection by a customer of a product for vending through activation of a product selection mechanism which activates a motorized positioning mechanism; (c) moving the motorized positioning mechanism to the selected product container, the motorized positioning mechanism being capable of moving in the storage cavity and being mounted adjacent to the front of the storage cavity, and including two Y-rail assemblies oriented in a generally vertical direction, an X-rail assembly oriented in a generally horizontal direction and moveably connected at each end to a Y-rail assembly, the X-rail assembly movable in the Y plane along the Y-rail assemblies, a housing for a gripping mechanism mounted on the X-rail assembly and movable in the X plane along the X-rail assembly, a gripping mechanism having one or more oppositely positioned fingers mounted in the housing and movable horizontally in the Z plane for removing vended product from the columnar trays and transporting and depositing the product in the delivery port assembly; (d) removing the product container to be vended from the foremost position in the column containing the selected product containers by (i) positioning the gripping mechanism such that the fingers of the gripping mechanism are slightly above the column, (ii) extending in the Z direction the gripping mechanism forward toward the end of the selected column such that the fingers are located on either side of the foremost product container, (iii) then moving the gripper mechanism down to open the gates on the front of the tray, (iv) then closing the fingers or an alternate mechanism of the gripping mechanism against the product container, (v) then raising the container above the lip at the front of the tray, and (vi) finally retracting the gripping mechanism into the gripping mechanism housing closing the gate behind the product that has been retrieved; (e) transferring the removed product container to the delivery port assembly using the motorized positioning mechanism to align the product container over a chute mounted adjacent to the delivery port assembly; (f) dropping the product container into the chute by releasing the fingers on the gripping mechanism; and (g) delivering the product container to the customer by closing the chute thereby placing the product container into the delivery port and pivoting the delivery port open for product container retrieval. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane. 
     Another aspect of the invention includes the components and methods associated with a product gripping mechanism that is capable of moving in the Z direction, and that can reliably retrieve, hold and release any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights. 
     Another aspect of the invention includes the components and methods associated with adjustably removable product support trays for holding queues of product containers, each tray designed to urge products toward one end, and having a unique gate structure at that end for selectively releasing products from the queues. 
     Another aspect of the invention includes the components and methods associated with a delivery port including a pivotally attached chute for receiving a product container, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior. 
     Another aspect of the invention includes the components and methods associated with an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane, and a product gripping mechanism attached to the carriage that is capable of moving in the Z direction to reliably retrieve, hold and release any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane; adjustably removable product support trays for holding queues of product containers, each tray designed to urge products toward one end and having a unique gate structure at that end for selectively releasing products from the queues; and a product gripping mechanism attached to the carriage that is capable of moving in the Z direction to reliably retrieve from the trays and therafter hold and release any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane; adjustably removable product support trays for holding queues of product containers, each tray designed to urge products toward one end and having a unique gate structure at that end for selectively releasing products from the queues; a product gripping mechanism attached to the carriage that is capable of moving in the Z direction to reliably retrieve from the trays and therafter hold and release any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights; and a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane; adjustably removable product support trays for holding queues of product containers, each tray designed to urge products toward one end and having a unique gate structure at that end for selectively releasing products from the queues; a product gripping mechanism attached to the carriage that is capable of moving in the Z direction to reliably retrieve from the trays and therafter hold and release any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights; a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior; and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane, and adjustably removable product support trays for holding queues of the product containers, each tray designed to urge products toward one end and having a unique gate structure at that end for selectively releasing products from the queues. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane; adjustably removable product support trays for holding queues of the product containers, each tray designed to urge products toward one end and having a unique gate structure at that end for selectively releasing products from the queues; and a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane; adjustably removable product support trays for holding queues of the product containers, each tray designed to urge products toward one end and having a unique gate structure at that end for selectively releasing products from the queues; a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior; and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane, and a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane; a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior; and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane, and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane, a product gripping mechanism attached to the carriage that is capable of moving in the Z direction to reliably retrieve, hold and release any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights, and a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane, a product gripping mechanism attached to the carriage that is capable of moving in the Z direction to reliably retrieve, hold and release any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights; a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior; and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane, a product gripping mechanism attached to the carriage that is capable of moving in the Z direction to reliably retrieve, hold and release any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights; and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a positioning and transportation system that is capable of accurately and efficiently moving a carriage to different desired locations along the X-Y plane; adjustably removable product support trays for holding queues of the product containers, each tray designed to urge products toward one end and having a unique gate structure at that end for selectively releasing products from the queues; and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a product gripping mechanism that is capable of reliably retrieving, holding and releasing any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights, and adjustably removable product support trays for holding queues of the product containers, each tray designed to urge products toward one end and having a unique gate structure at that end for selectively releasing products from the queues to the gripping mechanism. 
     Another aspect of the invention includes the components and methods associated with a product gripping mechanism that is capable of reliably retrieving, holding and releasing any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights; adjustably removable product support trays for holding queues of the product containers, each tray designed to urge products toward one end and having a unique gate structure at that end for selectively releasing products from the queues to the gripping mechanism; and a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior. 
     Another aspect of the invention includes the components and methods associated with a product gripping mechanism that is capable of reliably retrieving, holding and releasing any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights, and a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior. 
     Another aspect of the invention includes the components and methods associated with a product gripping mechanism that is capable of reliably retrieving, holding and releasing any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights; a delivery port including a pivotally attached chute for receiving a product container from the gripping mechanism, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior; and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a product gripping mechanism that is capable of reliably retrieving, holding and releasing any of a wide variety of containers of different sizes, shapes, deformabilities and/or weights, and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with adjustably removable product support trays for holding queues of product containers, each tray designed to urge products toward one end, and having a unique gate structure at that end for selectively releasing products from the queues, and a delivery port including a pivotally attached chute for receiving a product container, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior. 
     Another aspect of the invention includes the components and methods associated with adjustably removable product support trays for holding queues of product containers, each tray designed to urge products toward one end, and having a unique gate structure at that end for selectively releasing products from the queues; a delivery port including a pivotally attached chute for receiving a product container, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior; and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with adjustably removable product support trays for holding queues of product containers, each tray designed to urge products toward one end, and having a unique gate structure at that end for selectively releasing products from the queues, and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     Another aspect of the invention includes the components and methods associated with a delivery port including a pivotally attached chute for receiving a product container, transferring it into an output bucket and urging it forward in the bucket for removal by a customer while preventing unauthorized access from the exterior, and an environmental control system (heating or cooling) having its operational components included in a single modular unit that may be easily removed and swapped for another unit for repair or replacement. 
     It is therefore an object of the present invention to provide a vending machine that is capable of storing, retrieving and delivering product containers having any of a wide variety of sizes, shapes, deformabilities and/or weights. 
     It is also an object of the present invention to provide a vending machine that is capable of simultaneously storing product containers having any of a wide variety of different sizes, shapes, deformabilities and/or weights, and retrieving and delivering any of such containers. 
     It is also an object of the present invention to provide a vending machine that allows the customer to view the products available for vending through a transparent front panel. 
     It is also an object of the present invention to provide a vending machine having front-facing racks or shelves that can be easily restocked from their rear ends forward. 
     It is another object of the present invention to provide a gripping mechanism for use in a vending machine that is capable of retrieving and delivering product containers having any of a wide variety of different sizes, shapes, deformabilities and/or weights. 
     It is also an object of the present invention to provide a gripping mechanism having movable fingers for securely grasping containers of different sizes, shapes, deformabilities and/or weights. 
     It is also an object of the present invention to provide a gripping mechanism for reliably retrieving, holding and releasing product containers of different sizes, shapes, deformabilities and/or weights. 
     It is also an object of the present invention to provide a gripping mechanism for transporting product containers of different sizes, shapes, deformabilities and/or weights from the ends of their respective queues to a delivery area inside a vending machine. 
     It is also an object of the present invention to provide a gripping mechanism that works in conjunction with one or more gates located at the ends of trays containing product containers to remove the endmost product container from each such tray. 
     It is another object of the present invention to provide a positioning system for moving a carriage along the X-Y plane. 
     It is also an object of the present invention to provide an X-Y positioning system for use in a vending machine including a pair of adjustably positionable Y-rails supporting a moveable X-rail that supports a carriage that is moveable along the X-rail for transporting product containers inside the machine. 
     It is also an object of the present invention to provide a positioning system for use in a vending machine that is capable of moving along the X-Y plane adjacent to any of the product queues inside the machine, and to a delivery port. 
     It is also an object of the present invention to provide a positioning system for use in a vending machine that may be mounted in the cabinet or door of the machine. 
     It is also an object of the present invention to provide a positioning system for use in a vending machine that supports a product gripping mechanism for retrieval, transport and delivery of product containers inside the machine. 
     It is another object of the present invention to provide adjustable shelves supporting product trays for use in a vending machine that extend from the back to the front of the machine establishing queues of product containers that urge the products forward in the trays. 
     It is also an object of the present invention to provide product support shelves and trays for use in a vending machine that may be positioned in different locations inside the machine in order to accommodate product containers of different heights, sizes and shapes. 
     It is also an object of the present invention to provide product trays for use in a vending machine having one or more moveable gates at their ends to prevent products from exiting each tray until moved aside to allow the endmost product to be removed from the tray. 
     It is another object of the present invention to provide a delivery port for use in a vending machine for receiving a product container from within the machine and delivering it to the outside while preventing unauthorized access to the interior of the machine through the port. 
     It is also an object of the present invention to provide a delivery port for use in a vending machine having a closable chute through which a product container is received, the chute closing after receipt to prevent unauthorized access to the interior of the machine. 
     It is also an object of the present invention to provide a delivery port for use in a vending machine that is positioned in a comfortable location for retrieval of a vended product by a customer. 
     It is another object of the present invention to provide a modular component parts for use in a vending machine that may be easily removed from the machine and replaced in the field. 
     It is also an object of the present invention to provide a vending machine having easily removable and replaceable component parts so that a working component part may be quickly swapped for a failing one, minimizing the down time of the machine. 
     It is also an object of the present invention to provide a modular environmental control system and other component parts for use in a vending machine providing the ability to quickly remove and replace such component parts to reduce the length of time that the vending machine must be opened for access, thereby preserving the temperature of the products inside. 
     Additional objects of the invention will be apparent from the detailed descriptions and the claims herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a vending machine of the present invention viewed from the right side. 
         FIG. 2  is a front perspective view of a vending machine of  FIG. 1  viewed from the left side. 
         FIG. 3  is a perspective view of a door of a vending machine of the present invention viewed from the inside looking out. 
         FIG. 4  is a perspective view of the door of  FIG. 3  viewed from the outside looking in. 
         FIG. 5  is a perspective view of a door including components of a vending machine of the present invention viewed from the inside looking out. 
         FIG. 6  is a perspective view of the door of  FIG. 5  viewed from the outside looking in. 
         FIG. 7  is a front perspective view of a cabinet for a vending machine of the present invention without door viewed from the right side. 
         FIG. 8  is a rear perspective view illustrating the components of a positioning system of the present invention. 
         FIG. 9A  is a top perspective view of a carriage support (X rail) assembly of the present invention. 
         FIG. 9B  is a bottom perspective view of the carriage support (X rail) assembly of  FIG. 9A . 
         FIG. 10  is an exploded view of the carriage support (X rail) assembly of  FIGS. 9A and 9B . 
         FIG. 11A  is a top perspective view of a carriage assembly of the present invention. 
         FIG. 11B  is a bottom perspective view of the carriage assembly of  FIG. 11A . 
         FIG. 12  is an exploded view of the carriage assembly of  FIGS. 11A and 11B . 
         FIG. 13  is a side perspective view of a support rail (Y rail) of the present invention, including a support assembly. 
         FIG. 14  is a detailed side perspective view of the support assembly (Y-rail) shown in  FIG. 13 . 
         FIG. 15  is an exploded view of the support assembly of  FIG. 14 . 
         FIG. 16A  is a perspective view of a housing and gripper assembly of the present invention with the gripper retracted into the housing. 
         FIG. 16B  is a perspective view of the housing and gripper assembly of  FIG. 16A  with the gripper extended from the housing. 
         FIG. 17A  is a front perspective view of a gripper assembly of the present invention. 
         FIG. 17B  is a rear perspective view of the gripper assembly of  FIG. 17A . 
         FIG. 18  is an exploded view of the gripper assembly of  FIG. 17A . 
         FIG. 19A  is a front perspective view of a housing assembly of the present invention. 
         FIG. 19B  is a rear perspective view of the housing assembly of  FIG. 19A . 
         FIG. 20  is an exploded view of the housing of  FIGS. 19A and 19B . 
         FIG. 21  is a front perspective view of a cabinet for a vending machine of the present invention without door viewed from the left side. 
         FIG. 22  is a front perspective view of an open cabinet and door for a vending machine of the present invention without trays or shelves viewed from the left side. 
         FIG. 23  is a front perspective view of a cabinet for a vending machine of the present invention with trays and shelves but without door viewed from the right side. 
         FIG. 24  is a front perspective view of the cabinet of  FIG. 23  viewed from the left side. 
         FIG. 25  is a front perspective view of a shelf of the present invention for supporting tray assemblies. 
         FIG. 26  is a front perspective view of a tray assembly of the present invention. 
         FIG. 27  is an exploded view of the tray assembly of  FIG. 26 . 
         FIG. 28  is a left side perspective view of a delivery port of the present invention. 
         FIG. 29  is a right left side perspective view of the delivery port of  FIG. 28 . 
         FIG. 30  is an exploded view of the delivery port of  FIG. 28 . 
         FIG. 31  is a perspective view of a delivery chute of the present invention. 
         FIG. 32  is another perspective view of the delivery chute of  FIG. 31 . 
         FIG. 33  is an exploded view of the delivery chute of  FIG. 31 . 
         FIG. 34  is a front perspective view of an open cabinet for a vending machine of the present invention with environmental control system but without door viewed from the left side. 
         FIG. 35  is a left side perspective view of an environmental control system of the present invention. 
         FIG. 36  is a right side perspective view of the environmental control system of  FIG. 35 . 
         FIG. 37  is an exploded view of the environmental control system of  FIG. 35 . 
         FIG. 38  is back view of a gripper of the present invention showing the fingers engaged with a product container having a first shape. 
         FIG. 39  is back view of a gripper of the present invention showing the fingers engaged with a product container having a different shape. 
         FIG. 40  is a front perspective view of a vending machine of the present invention having a transparent front panel, showing the removal of a product container from a tray by the robotic gripping mechanism. 
         FIG. 41  is detailed view of area enclosed in circle A of  FIG. 40 . 
         FIG. 42  is a rear perspective view of the door of the invention showing transfer of a product container from the gripping mechanism to a chute 
         FIG. 43  is a detailed view of area enclosed in circle A of  FIG. 42 . 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of the invention is described herein in the context of vending exemplary bottled products having containers that are elongated in the vertical direction and round in cross-section (e.g., containers such as those illustrated  FIGS. 38 and 39 ), to provide a convenient point of reference. However, the vending machine, component parts and methods of the present invention are not restricted to any particular container kind, size, shape or deformability, and the context provided for describing the exemplary embodiment is not intended to limit the scope of the invention, its components and/or methods, nor to limit application of any of the invention, its components and/or methods to the particular embodiment or containers described, nor should it so be construed. 
     Referring then to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, it is seen that an exemplary cabinet for a vending machine of the present invention is illustrated in  FIGS. 1-7 ,  21 - 24  and  40 . Referring particularly to  FIGS. 7 and 21 , it is seen that cabinet  40  includes an exterior top panel  41 , left side panel  42 , right side panel  43 , back panel  44 , and bottom (floor) panel  45 . A removable extension panel  46  is also provided at the floor of the cabinet  40  extending out from the front thereof below the door  48  as shown in  FIGS. 1 and 2 . An insulated dividing wall or bulkhead  51  is provided inside cabinet  40  separating the interior into an upper chamber  58  and a lower chamber  59 . Referring to  FIG. 34 , an interior panel  62  is provided on the right side of the upper chamber  58 , defining a plenum behind wall  182  between panel  62  and exterior panel  43 . Panels  41 - 43 ,  182  and the other walls of the upper chamber  58  are insulated so that products may be stored in chamber  58  at controlled temperatures. The lower chamber  59  is designed to hold a modular climate control apparatus, as described more fully below. One or more openings  54  and  55  are provided in wall  51  to allow the flow of air between the lower chamber  59  and the upper chamber  58 . 
     An insulated door  48  is attached to the front of cabinet  40  as shown in  FIG. 22 , preferably using hinges  47  or other suitable mounting devices. A transparent panel  50  is provided in the upper portion of door  48  generally corresponding to upper chamber  58  so that a customer may view the interior of chamber  58  from the outside (see  FIGS. 1 and 2 ). As shown in  FIGS. 4-6 , door  48  is divided into left side  65  and right side  66  compartments by insulated wall  63 . The larger left side compartment  65  corresponds generally to the upper chamber  58  bounded by interior wall  62 , and the smaller right side compartment  66  corresponds generally to the portion of the upper chamber between interior wall  62  and exterior wall  43 . The left side compartment  65  includes transparent panel  50 . The right side compartment  66  houses, among other things, the product delivery port mechanism, generally  150 , the product selection electronics, generally  186 , the money acceptance system, generally  195 , and the locking mechanism, generally  197 . 
     A lower insulated panel  49  is provided in the front of door  48  below panel  50  corresponding generally to lower chamber  59 . Another insulated panel  56  that includes a gasket  57  is provided adjacent to lower panel  49 . The gap between panels  49  and  56  is of sufficient size to receive the moveable X-rail, a housing  30  and a gripper mechanism  10  when not in use, as shown in  FIG. 5  and described more fully below. When closed, door  48  fits flush against the top and side panels  41 - 43  of cabinet  40 . The gasket  57  of insulated panel  56  fits flush against the corresponding edge of insulated dividing wall  51 . A seal  52  is provided inside door  48  as shown in  FIG. 22  which seals against the inside edges of top and side panels  41  and  42 , against panel  56  (compare to  FIG. 3 ), and against the edge of interior panel  62 . Thus, when door  48  is closed, upper chamber  58  is completely insulated (except for openings  54  and  55 ), including the gap area holding the housing  30  and gripper mechanism  10 . 
     A base panel  46  is provided that may be detached from the cabinet base, such that when panel  46  is removed and the vending machine door opened, the machine may be rotatably angled through an entryway that is narrower than the depth of the vending machine. This allows for moving the large vending machine of the preferred embodiment through a standard doorway. 
     Mounted inside door  48  is a positioning system that is capable of moving throughout a plane defined by X and Y axes. The X-Y positioning system is mounted inside door  48 , as shown in  FIG. 5 . The X-plane is oriented horizontally with respect to the door. The Y-plane is oriented vertically with respect to the door. There is also a Z-plane that extends orthogonally from the X and Y planes in the direction of the rear wall. An isolated view of the X-Y positioning system is illustrated in  FIG. 8 . 
     The X-Y positioning system includes a pair of generally vertically oriented rail assemblies  72  (Y-rails) that are attached, respectively, to the left and right sides of the inside vertical frame of door  48 . Mounted within each rail  72  is a track  75 . Each track  75  preferably includes a set of regularly-spaced perforations  76  for receiving the cleats  82  of associated sprockets  86  which, as detailed below, provide for movement of a carriage support (X-rail) assembly  80  along the tracks  75  of the Y-rails. See  FIGS. 13 and 14 . The position of each of rails  72  may be slidably adjusted relative to the panel it is attached to, for proper synchronization with the associated sprockets  86  in order to level the X-rail assembly and assure smooth movement thereof. The perforated tracks  75  extend substantially the length of the Y-rails  72 , which, in turn, extend substantially the length of the inside frame of door  48 , and once adjusted, are held in place using screws or other appropriate attaching devices. Stops  74  are provided to arrest the downward movement of the X-rail. It is to be appreciated that different alternative types of tracks  75  may be provided including without limitation smooth tracks for engagement with rubberized members (instead of toothed sprockets or tractor drives), toothed tracks for engagement with cogs of gear-like members, timing belts with pulleys, and the like. 
     A carriage support (X-rail) assembly  80  is illustrated in the top and bottom perspective views of  FIGS. 9A and 9B , and the exploded view of  FIG. 10 . Each X-rail assembly  80  includes a cover piece  84  having nearly mirror-image end piece assemblies  85  attached at both ends. Each end piece assembly  85  includes a splined coupling  87  that engages a corresponding toothed opening  88  in sprocket  86 . Sprockets  86  are part of a larger moveable assembly  90  that is slidably mounted in each of the vertical Y-rails. See  FIGS. 14 and 15 . Wheels  83  on assembly  90  follow grooves  77  in rails  72  to guide the moveable assemblies  90  vertically along the Y-rails  72 . Rotation of splined coupling  87  engaged in openings  88  imparts rotation to sprockets  86  which, in turn, causes cleats  82  to engage perforations  76  of track  75  moving each assembly  90  up or down, depending on the direction of rotation. This rotational movement is imparted simultaneously to both couplings  87  through shaft  81  coupled to motor  89 , causing the X-rail assembly  80  to move up or down relative to the Y-rails. As above, it is to be appreciated that different types of tracks and different means for engaging such tracks may be implemented without departing from the scope of the invention. 
     It will be appreciated that the force of gravity makes downward movement along the Y-rails  72  easier than upward movement. Because of the significant weight supported by the X-rail  80  (including a carriage assembly  100 , housing  30 , and robotic gripping mechanism  10 —particularly when laden with a heavy fluid-filled product container), in an alternative embodiment a torsion spring or counterweight system may be provided to assist motor  89  in raising the X-rail assembly  80  in an upward direction against gravity. The assistance of the spring or counterweight is not needed for downward movement. In another alternative embodiment, the X-rail assembly  80  may be provided with a dual motor drive system for moving the X-rail assembly  80  up or down relative to the Y-rails for increased upward power and downward control. 
     A moveable carriage assembly  100  is provided for horizontal movement along the X-rail assembly  80 . Mounted below cover  84  is a horizontally oriented rail  73  containing a pair of downwardly oriented grooved flanges  79  which serve as guides for wheels  92  of carriage assembly  100 , shown in  FIGS. 9B and 10 . A pair of tracks  78 , preferably but not necessarily perforated, are mounted on the underside of the rail  73  for receiving the teeth  104  of rotatable sprockets  105  mounted in carriage assembly  100 . Referring to the exploded view of  FIG. 12 , it is seen that the pair of sprockets  105  are operated by motor  109  for moving carriage assembly  100  horizontally (left or right) along tracks  78  of the rail  73 . Operation of the motor  109  turns the pair of sprockets  105  whose teeth are engaged with the holes in the tracks  78  causing movement of the carriage assembly  100  horizontally along the X-rail, as wheels  92  travel along guide flanges  79 . A flange  107  is attached to carriage assembly  100  to support a housing and a gripping mechanism described more fully below. Vertical movement of the X-rail assembly  80  along the Y-rails  72  in conjunction with horizontal movement of the carriage assembly  100  along the X-rail  73  allows the carriage assembly, and the housing  30  and gripping mechanism  10  it supports, to be moved to any location on the X-Y plane defined by the X and Y rails  72  and  73 . As above, it is to be appreciated that different types of tracks and different means for following such tracks may be implemented without departing from the scope of the invention. A sensor (not shown) on the X-rail assembly  80  is used to detect whether the X-rail assembly  80  is in a “home” position relative to the Y-rails  72 . 
     A housing  30  is provided for holding a gripping mechanism  10 . In the exemplary embodiment illustrated in  FIGS. 19 and 20 , it is seen that housing  30  includes a main body member  33 , having a pair of upper support members  34  that are spaced apart from each other and mounted to the body member  33 , a main body cover  31 , and support member covers/flanges  32 . Body member  33  is removably attached to the carriage assembly  100  so that it may be easily detached for removal, repair and replacement of the housing  30  and/or the associated gripping mechanism  10 . When assembled, as carriage assembly  100  moves throughout the X-Y plane, it carries housing  30  and gripping mechanism  10  along with it. Each of the upper support members  34  includes a horizontally oriented track  35 , preferably including perforations  36  corresponding to the teeth  17  of sprockets  16  of the gripper mechanism  10 . Track  35  supports the gripper mechanism  10 , and provides a path along which it can move horizontally in the Z direction. As above, it is to be appreciated that different types of tracks and different means for engaging such tracks may be implemented without departing from the scope of the invention. 
     Housing  30  also includes a sensor  39  mounted on body  33 . Sensor  39  is used to sense the presence/location of shelves or trays in the cabinet and is in communication with a processor. Sensor  39  may be optical, magnetic or otherwise. Housing  30  may also include a separate sensor which is used to detect the housing being in a “home” position along the X-rail assembly  80  inside the vending machine cabinet. Housing  30  may also include yet another sensor that is used to detect whether the gripping mechanism  10  is fully retracted on track  35 . 
     It is to be understood that the components of the housing  30  are not limited to the particular locations depicted, but may be installed in various alternative locations, and in various alternative combinations, without affecting the functionality of the housing or gripping mechanism. For example, it is to be understood that said Z-axis supports  34  and track  35  may be mounted at different locations on the housing  30  such as underneath, or on either side of, the main body  33 , or flush against the rear end of the body. The sensor  39  may also be installed in various alternative locations, such as, but not limited to, the other arm  34  of body  33  flange of the housing, or any side of the housing  30 , so long as the locations of the corresponding sensed elements on the trays/shelves are likewise adjusted. 
     The gripping mechanism  10  is movably mounted in the housing  30  and is designed to be extended and retracted from the housing in order to retrieve a selected product from a queue, as shown in  FIGS. 16A and 16B . Referring to the detailed illustrations of  FIGS. 17-18 , it is seen that the gripping mechanism  10  includes a plurality of oppositely positioned movable fingers  12  that are urged inwardly by a plurality of corresponding biasing devices or springs  27 . It is preferred that fingers  12  be provided in pairs that are positioned directly across from each other, and exemplary illustrated embodiment includes three pairs of oppositely positioned movable fingers  12 . However, opposing fingers  12  need not be provided in pairs, and may be offset from each other. For example, the number of fingers on each side need not be the same, and the fingers  12  may be provided, for example, in an offset pattern, or in any other suitable combination. 
     Each moveable finger  12  is provided with a replaceable frictional pad  14  for improved frictional engagement against the surface(s) of a container  98  to reduce slippage and provide a firm grip. Pads  14  may be made of fabric, plastic, rubberized or other suitable material having a desired (preferably high) frictional coefficient. A special pad  15  is provided on each of the bottom most fingers  12  to provide additional frictional engagement at the bottom of the container  98  where there is expected to be significant weight. Slip on covers may be used as an alternative to the pads  14 . 
     Referring to the exemplary exploded view of  FIG. 18 , it is seen that fingers  12  are urged inward by springs  27 , but are held off by the action of moveable blocks  3  and  13  that are linked to driver  4  by pivotally mounted linking members  5 . Each finger  12  has its own spring  27  and hold off block  13 . The operation of motor  9  causes driver  4  to move up or down. At rest, control member or driver  4  is in an upward position as shown in  FIG. 17B , with fingers  12  being held off by blocks  3  and  13 . When moved down, driver  4  causes linking members  5  to pivot downward forming a “V” shape, and pulling blocks  3  and  13  toward the center of the unit. This action allows springs  27  to urge fingers  12  toward the center to grasp an object, such as a product container  98 , as illustrated in  FIGS. 38 and 39 . Since each finger  12  has an independent spring  27  and hold off block  13 , the each finger  12  may travel a different distance until it comes into contact with a part of the container  98 . This provides secure gripping of container  98 , by providing frictional engagement at many different locations and depths. The multiple independently moveable fingers  12  of the gripper allow for secure engagement with a wide variety of containers having different sizes, shapes, weights, and/or deformabilities. Fingers  12  may be retracted by the upward movement of driver  4  which is assisted by spring  25 . Such upward movement causes all of the fingers  12  to be held off by blocks  3  and  13 , thereby releasing the product container  98  and preparing the gripper to engage another container. 
     It is to be appreciated that the moveable fingers  12  should be of generally the same length, but fingers  12  and their associated pads  14  and  15  need not be of the same width or cross sectional area. In some applications, broader fingers with wider surface areas may be preferred; whereas, in other applications smaller or more narrow fingers; and combinations of different sizes and shapes for fingers  12  and their associated pads may also be employed in the same gripper  10 . It is to be appreciated that fingers  12  need not have a flat cross section (as illustrated), but may be provided having any suitable cross-sectional shape such as a bowed, semi-circular or C-shaped configuration, or fingers  12  may be provided as cooperating half-sleeves. 
     The gripping mechanism also includes a pair of lower fixed-position fingers  19 . Fixed fingers  19  are used to temporarily push out of the way one or more spring-loaded retaining gate(s)  131  and an optional spring-loaded dividing wall extension or arm  129 , both of which are located at the end of each tray  120 , as shown in  FIG. 26  and discussed more fully below. It is to be appreciated that the lowermost set of movable fingers  12  may be provided between the fixed position fingers  19  in the exemplary embodiment. 
     The gripping mechanism  10  is capable of moving backward and forward in the Z direction as illustrated in  FIGS. 16A and 16B . This movement is generally perpendicular to the X-Y plane defined by the positioning system, but may be tilted at an upward or downward angle to accommodate proper interaction with the trays  120 , as discussed more fully below. In the preferred embodiment, the Z movement is tilted upward at an angle of about six degrees (6°) to accommodate the corresponding downward angle of the trays  120 . The gripper  10  is extended as shown in  FIG. 16B  prior to engagement of the fingers  12  around a product container  98 . This allows the fingers to be brought into close proximity with the forward-most product container  98  in a given queue, and then retracted ( FIG. 16A ) after the container has been grasped. Movement of the gripper  10  and its associated fingers  12  and  19  in the Z direction is accomplished using motor  6  which rotates sprockets  16 . The teeth  17  of sprockets  16  engaged the pair of perforated tracks  35  provided on support arms  32  on opposite sides of housing  30  holding the gripping mechanism. A pair of wheels  8  are also provided to guide and stabilize the Z movement. Operation of motor  6  causes the gripping mechanism to extend forward in the Z direction out of and away from the gripping mechanism housing thereby causing fingers  12  and  19  to be extended to the foremost container at the end of a column and similarly retracting the gripping mechanism from the end of the selected column back into the gripping mechanism housing. 
     The housing  30  also supports a sensor  39 , shown in  FIG. 20 , oriented in a forward looking direction to permit scanning for a reflector element  137  positioned on each tray  120  as discussed in the detailed description of the trays below. It is preferred that sensor  39  be a polarized light emitting retro-reflective optical device that can only see the light as reflected off of the target reflector  137  (e.g., a corner cube type) so that it is not affected by ambient light interference, or flashy product containers. However, any other suitable sensing mechanism may be used such as a reed switch located on the housing, and magnets located on each tray. This sensor is used during a startup sequence of the vending machine to calibrate the current positions of all of the product trays so that the queues of products in those trays may later be accessed by the gripping mechanism. This also allows the positions of the trays to be moved to accommodate different sizes of product containers. If moved, the presence of each tray is again sensed, and the position calibrated and compared with the positions previously stored in memory before the tray was moved. Adjustments to the number of available selections (trays) are then automatically made in the control software, without any operator intervention. 
     The products to be vended are maintained in a plurality of tray assemblies  120  which are mounted on a plurality of adjustable shelf assemblies  140  that are deployed in the temperature-controlled upper chamber  58 / 65 . Exemplary shelf assemblies  140  are illustrated in  FIG. 25 , and exemplary tray assemblies  120  supported by the shelves are illustrated in  FIGS. 26 and 27 . Installed shelves and trays are shown in  FIGS. 1-2  and  23 - 24 . Each shelf assembly  140  includes a skeletal assembly having a front flange  141 , two mirror-image side flanges  142 , and a rear flange  144  forming a generally rectangular frame as shown in  FIG. 25 . A plurality of mirror image left and right side guide flanges  145 ,  146  are provided on the frame, forming elongated channels extending from front to back for receiving the tray assemblies  120 . Each of the guide flanges  145 ,  146  includes an elongated groove  148  extending from front to back, for receiving one of protruding stop rods  126 . Each groove  148  includes an enlarged flange  147  at the front, and a recessed notch  149  immediately behind flange  147 . Notch  149  is designed to receive a corresponding pin or stop rod  126  on each tray assembly  120  to facilitate loading of the trays, as discussed more fully below. 
     Rear flange  144  is raised with respect to front flange  141  such that the intermediate guide flanges  145 ,  146  are tilted at a downward angle from back to front. This tilt helps facilitate gravitational movement of products toward the front of the tray assemblies  120 . The angle may be varied according to the size, shape and weight of the products to be vended, but an exemplary angle may be approximately six degrees (6°). 
     The inside surfaces of cabinet walls  42  and  43  are provided with a plurality of hooks  151  for engagement with corresponding openings  152  on left and right side shelf flanges  142 . Hooks  151  are provided in numerous different locations in order to allow shelf assemblies  140  to be moved to different locations inside the temperature-controlled upper chamber  58 / 65  of cabinet  40 . This permits re-positioning of product shelves, to either allow more product selections, or to increase spacing between shelves to accommodate taller packages. A plurality of shelves may be provided in the upper chamber, depending upon the height of the product containers to be vended. It is to be appreciated that the positions of the shelf assemblies  140  within the chamber may be adjusted according to the requirements of the products to be vended. 
     Turning to  FIGS. 26 and 27 , it is seen that the exemplary tray assemblies  120  each define a pair of parallel columns extending longitudinally from back to front. Each tray assembly includes a floor  121 , two product slider tracks  127  attached to floor  121 , two side walls  122 , and a partial rear wall  124 . The tops of side walls  122  preferably include a longitudinal cap or flange  123  for rigidity. A longitudinal separating wall  125  is provided down the center of each tray defining the left and right columns or queues of each tray. A stop pin  126  is provided at the back of each tray, which protrudes out a slight distance from side walls  122 . Clips  139  are used to raise slider tracks  127  from front to back. Each tray  120  is designed to be slidably installed between guide flanges  145 ,  146  of the shelf assembly  140 . Each tray  120  may be pulled forward for loading of products, with stop pin  126  fitting into notch  149 . The engagement of stop pin  126  into notch  149  prevents tray  120  from being disengaged from the shelf assembly  140 , while at the same time allowing tray  120  to pivot down in a hinged fashion on stop pin  126  for easy loading of product containers. It is to be appreciated that trays having a single or multiple queues may also be employed. The more columns per tray, the fewer guides needed, however the heavier the tray when being restocked. 
     In one embodiment, a low friction molded track  127  is attached to the interior floor  121  of each tray column. Track  127  may be made of any number of materials and configurations, but in the preferred embodiment it is a ribbed structure made of low-friction plastic such as acetal. Track  127  may be raised at the back using clips  139  to provide a slope for forward gravitational movement of products along track  127 . 
     In one embodiment, each tray column is also provided with a pusher element  136  which exerts a force upon the containers  98  in the queue urging them forward. In this embodiment, a channel is provided for each queue on bottom panel  121  and oriented to guide pusher  136  so that it may slide from back to front. At the rear of each bottom channel is a small detent which, as discussed below, holds pusher  136  in place at the back of a column during product loading. Pusher  136  is pulled toward the front of a column by a self-coiling spring member  138  which is deployed at the bottom of each queue. One end of spring member  138  is attached to a roller which is mounted on the rear of pusher  136 . The other end of spring member  138  is attached to the bottom front of track  127 . Tension from spring member  138  causes pusher  136  to urge the product containers  98  in the queue toward the front of each column. When a product is removed from the front of a queue, the tension exerted on pusher  136 , together with gravity, compels the remainder of the products in the column to move forward until the product formerly second in line is now the foremost product to be the next product vended from the column. As pusher  136  moves closer to the dispensing end of a column, spring member  138  coils around the roller. When loading a column in a tray, pusher  136  is manually slid to the rearmost position in the tray where it is wedged onto cross-bar  126  using detent which holds pusher  136  in place. When a tray is returned to a dispensing position on a shelf, each of the pushers  136  on the tray (which have been set in the loading position) are automatically released as a result of contact between the rear of the pusher and the back wall of the cabinet. Once pusher  136  is released, spring member  138  draws it into contact with the last product in the queue, thereby urging it forward in the manner previously discussed. 
     In the illustrated embodiment, a frame assembly  130  is provided at the front of each tray  120 . Each frame assembly includes an extension of central separating wall  125 , and extensions of side walls  122 . Frame assembly  130  may also include a lower flange or lip  135  along the bottom to prevent product containers  98  from exiting the queue. A target reflector  137  is provided on the front of each tray, preferably on lip  135 . Reflectors  137  are targets that are sensed by sensor  39  during the startup sequence to determine the location of each particular tray. The extension of separating wall  125  supports a downwardly moveable pivotally mounted arm  129  that is held in a substantially horizontal or “closed” position by a biasing member such as a spring  128 . Arm  129  can be opened by collapsing biasing member  128  through the exertion of minimal downward pressure on the top of the arm. When depressed, arm  129  recedes into a hollow are in the separating wall extension. Depression of arm  129  occurs during the process of product retrieval and is accomplished by one of the fixed fingers  19  of the gripper mechanism  10  when it accesses one of the columns on either side of arm  129  while reaching into a queue to retrieve a selected product. See  FIG. 41 . 
     In the illustrated embodiment, each front frame assembly  130  also includes a pair of pivotally mounted gates  131  attached, respectively, to each of the side wall extensions of frame assembly  130 . Gates  131  may be mirror images of each other, and are provided at the front of each tray queue. Gates  131  are held in a substantially horizontal or “closed” position extending into or across the front of each respective queue by a biasing member such as a spring  132 , thus preventing product containers  98  in the queue from exiting through the front of the tray. The illustrated gates  131  pivot in the X-Y plane, but they may also be provided to pivot in the Z plane with a stop to prevent product containers from pushing them open. Each gate  131  is opened by exerting a downward pressure on the top of the gate. Depression of a gate  131  occurs during the process of product retrieval and is accomplished by one of the fixed fingers  19  of the gripper mechanism  10  when it accesses a queue. It is to be appreciated that during product retrieval, one of the fixed position fingers  19  depresses arm  129 , and the other of fixed position fingers  19  depresses one of gates  131  (i.e., the gate  131  associated with the queue (right or left) that is being accessed), thereby allowing the movable fingers  12  the opportunity to engage and remove the foremost product container  98  in the queue. It is to be appreciated that when the gripper  10  and fixed position fingers  19  are raised they lift the grasped product container  98  above lip  135 . The gripper is then retracted allowing arm  129  and gate  131  return to their original “closed” positions preventing other product containers  98  from exiting the queue. 
     In an alternative embodiment, a more simplified tray assembly  120  may be provided having a single column extending from back to front. This alternative tray has a floor  121  and side walls  122 , but no central separating wall  125 , nor the wall extension or arm  129 . Instead, the single tray column has but a single spring-mounted gate  131  which may be pivotally attached to either side wall  122 . Alternatively, a pair of gates  131  may be provided, one on each side wall  122 . The single tray embodiment may or may not be provided with the track  127  and/or the pusher assembly  136 . 
     A delivery area is provided in the door of the machine. In the illustrated exemplary embodiment, this delivery port includes two operative assemblies shown in  FIGS. 28-33  and  42 - 43 . The primary assembly is the delivery bucket  150  into which the vended product is transferred from a chute  160  and which opens to the outside allowing for retrieval of the vended product by the customer. The secondary assembly is a closable flap or chute on the inside of the door that receives the product that is dropped from the gripping mechanism  10 . Referring first to the bucket assembly of  FIGS. 28-30 , it is seen that the bucket  150  has an open top, and three connected side walls leaving one open side. The chute assembly  160  is attached to a panel in the door adjacent to the open side wall of the bucket to allow product containers to be delivered into the bucket  150 , as shown in  FIGS. 42-43 . Bucket  150  is pivotally mounted to the door  48 , such that it may pivot forward thereby tilting open at an angle away from the door sufficient to permit removal of the vended product by the customer. One or more sensors  154  in bucket  150  detect the presence of the container  98 . If no container is detected upon delivery from the gripping mechanism  10 , the electronics determine that the particular queue is empty and instruct the purchaser to make another selection. If a product container is detected, the sensor  154  also detects its removal, thereafter tilting the bucket closed. 
     Special electronics controlling the delivery port detect whether there is an obstruction in the delivery port caused by the presence of a human hand or other object, and if so, closing of the port is delayed until the obstruction is removed. Other electronics illuminate the bucket delivery area when the product is present. 
       FIGS. 31-33  and  42 - 43  illustrate an exemplary embodiment of a chute mechanism. This chute mechanism includes two parts, a primary chute  161 , and a secondary chute  162 . Primary chute  161  is pivotally attached to panel  63  in the door adjacent to the open side of bucket  150 , and may be tilted open in order to receive a vended product dropped from the gripping mechanism  10 . When tilted open, primary  161  and secondary  162  chutes lay against each other forming a single chute, as shown in  FIG. 32 . The gripping mechanism  10  is brought above the chute through the operation of the X-Y positioning system, fingers  12  are retracted, and the product container  98  is dropped into the chute, as shown in  FIGS. 42-43 . The product container  98  then slides down the secondary chute  162  into bucket  150 . Primary chute  161  is then closed, causing secondary chute  162  to extend out and away from primary chute  161  through the operation of linkages  165 , as shown in  FIG. 31 . This pushes the product container  98  into bucket  150  for delivery. Chute  162  does not extend beyond the thick insulated door panel  63 , allowing pivotal movement of bucket  150  without interference. Closing of chute  151  seals the interior of chamber  58  preventing the escape of the controlled atmosphere, and also preventing unauthorized access to the interior from the outside. 
     Once the selected product container is retrieved from its queue by the gripping mechanism and delivered to and dropped into the chute assembly portion of the delivery area in the door, the product container is moved into the bucket when the chute closes. Once the chute closes, the presence or absence of a product container  98  in the bucket  150  is detected by at least one sensor  154 , for example an optical emitter and detector. If there is no product container in the bucket, the bucket remains closed, and the customer is alerted (e.g., to make another selection). If there is a product container in the bucket, it is mechanically opened by tilting the bucket forward from the front of the vending machine which is caused when the bucket drive motor (not pictured) activating the delivery bucket drive link. Once the bucket is open, the customer retrieves the selected product and when the absence of the product is detected by sensor  154 , the bucket automatically closes. When closing, if the electronic system associated with the bucket detects an obstruction, the bucket will stop closing until the obstruction is removed. This keeps the bucket from closing on a customer&#39;s hand. 
     An alternative embodiment of the product delivery port utilizes a motor in communication with the bucket. The motor comprises a gear mechanism, a worm gear drive, and a locking mechanism in communication with the gear mechanism and drive. The motor prevents customers from forcibly prying open the bucket, since the locking gear mechanism of the motor prevents backdriving of the motor. This reduces the likelihood and frequency of product theft. An alternative embodiment of the product chute includes a bumper in the bucket at the base of the chute. 
     In one embodiment, the temperature inside the storage chamber  58  is controlled by heating or refrigeration equipment. Circulation of air is forced into upper chamber  58  through ducts  54  and  55 . Heating or refrigeration equipment is provided in lower chamber  59  to provide the heated or cooled air. This environmental control equipment is provided in a modular system  170  that may be easily accessed, removed and replaced to minimize the down time of the vending machine. A typical modular refrigeration unit is illustrated in  FIGS. 34-37 , and includes such components as a compressor  171 , drier  172 , evaporator  173 , condenser  174  and fan assembly  179 . All of these components, and others (such as foamed box  175 —see  FIG. 37 ) are mounted on a single easily-removable base  176  forming the modular unit  170 . 
     The exemplary modular environmental control unit  170  is removably deployed in the lower ambient chamber  59  of the cabinet and communicates to the upper chamber  58  through ducts  54  and  55 . In particular, cooler air produced by the exemplary refrigeration unit is forced into upper chamber  58  through outer duct  55  through opening  184 , and withdrawn from upper chamber  58  through inner duct  54  through opening  185 . Outer duct  55  is in communication with a vertical plenum formed between side wall  43 , front wall  182  and dividing wall  62  as shown in  FIG. 34 . A plurality of ventilation openings  181  are provided in wall  62  to allow air to be moved into upper chamber  58  from the plenum behind wall  182 . Ventilation openings  181  may be selectively blocked or left unblocked in different patterns in order to control the flow of air into chamber  58  according to such factors as the setup of the shelves and trays, as well the size and shape of the product containers therein. 
     It is to be appreciated that other electronic components  189  such as those for controlling the overall operation of the machine may also be deployed at any appropriate location such as in lower chamber  59  (as shown in  FIGS. 22-24  and  34 ), in the cabinet door, or split up over multiple locations such as in the gripper housing, with the delivery port, or elsewhere in different combinations. 
     The operation of the illustrated exemplary vending machine including all of the components identified above will now be described. It is to be appreciated that the invention is not limited to this illustrative combination of components, and that different combinations of these components may be utilized without departing from the scope of the invention. Upon initial power up, the control system performs a startup sequence to determine the locations of the trays  120 . This procedure is also repeated whenever door  48  is left open for a pre-defined period, such as 10 minutes. During the startup procedure, the housing  30  carrying sensor  39  scans in the Y direction, with sensor  39  identifying reflector targets  137  on trays  120 . The existence of each reflector target  137  is sensed and communicated to a processor that calibrates the coordinates of each of the shelves and their corresponding product trays. It is preferred that sensor  39  be a polarized light emitting retro-reflective optical device that can only see the light as reflected off of the particular reflector  137  (corner cube type) so that it is not affected by ambient light interference. However, any other suitable sensing mechanism may be used such as a reed switch located on the housing, and magnets located on each tray. The position of each shelf is recorded, and if positions have been previously recorded, the new positions compared with those previously stored to determine if any changes in shelf positions have occurred. Any adjustments to the number of available shelves are then automatically made in the control software, without any operator intervention. 
     To operate the illustrated embodiment, a customer views the available products through the transparent front door panel  50 , deposits money at  195 , and makes a selection using keypad  186 . Upon receipt and verification of the money and product selection, the X-Y positioning system is activated causing the X-rail assembly  80  to be moved vertically to the appropriate shelf, and the carriage assembly  100  to be moved horizontally to the appropriate queue of a tray  120 . These movements may occur simultaneously for quicker access of the product queue. Once the proper X and Y positions are reached in front of the selected queue, the gripping mechanism  10  is activated. The X-Y positioning is such that the fingers of the gripping mechanism are slightly above the selected queue. The gripping mechanism  10  is then extended forward in the Z direction (possibly at an angle, which may be around 6°), with fingers  12  open above the queue, such that the fingers  12  and  19  are on either side of the foremost product container  98  in the queue. After the gripper has been extended in the Z direction, the carriage assembly (X-rail) is lowered, causing fixed fingers  19  to come into contact with the spring-loaded gate  131  and spring-loaded arm  129  extension of the queue. The downward movement of fingers  19  temporarily moves these two spring-loaded parts out of the way. Fingers  12  are then closed around the container  98  to grip it, as shown in  FIG. 41 . The carriage assembly is then raised slightly so that the bottom of the gripped container may clear the lip  135  at the bottom of the queue. The gripper then retracts in the Z direction taking the product container  98  with it, retracting fixed fingers  19  away from the queue, releasing the two spring-loaded mechanisms which return to their original positions. 
     The product container  98 , held by fingers  12 , is then transferred to the delivery area using the X-Y positioning mechanism. When positioned above chute  161 , fingers  12  are released, causing the product container  98  to be dropped down chute  161 . Chute  161  then closes causing sub-chute  162  to push the product container  98  into bucket  150 . Meanwhile, the gripper housing is moved vertically in order to block chute  161  from being pushed open by a customer through the delivery port. Detector  154  verifies the presence of the container in the bucket  150 . If the product is present, the bucket  150  is tilted forward to allow the customer to retrieve it. 
     It is to be appreciated that different versions of the invention may be made from different combinations of the various features described above. It is to be understood that variations and modifications of the present invention may be made without departing from the scope thereof. It is also to be understood that the present invention is not to be limited by the specific embodiments disclosed herein, but only in accordance with the appended claims when read in light of the specification. 
     It is also to be understood that the present invention is not to be limited by the specific embodiments or combinations of the components or parts disclosed herein, nor by any of the exemplary dimensions set forth in the attached illustrations. In particular, any of the different components of the invention may be used independently of one another, in stand alone operations, or in independent situations apart from any particular vending machine. In addition, different permutations and combinations of the various components and parts disclosed herein may be employed in different vending machines to provide different sets of features and functionality.