Abstract:
A dispensing machine for dispensing items of hot food comprises a freezer compartment for storing items to be dispensed, a heating compartment, a dispensing location, and a transport mechanism for conveying items form the freezer compartment, via the heating compartment, to the dispensing location. The transport mechanism has a flexible transport web to which the items to be dispensed are secured. Driving means advance the web from the freezer compartment to the dispensing location. The web has code markings on it indicating the positions of the food items on the web. A code reader reads the code markings to control the driving means for advancing the web.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a dispensing machine for dispensing items of hot food, comprising a freezer compartment for storing the items to be dispensed, a microwave oven, a dispensing location and a transport mechanism for conveying items from the freezer compartment, via the microwave oven, to the dispensing location, the transport mechanism comprising a flexible transport web to which the items to be dispensed are secured and driving means for advancing the web from the freezer compartment to the dispensing location. 
     DESCRIPTION OF THE PRIOR ART 
     A dispensing machine as described above is known from GB-A-996,039. In this machine, an oven that is open from above and below is located inside the freezer compartment. The transport mechanism includes a wheel with a polygonal circumference positioned next to the top of the oven and allows an item that is to be dispensed to drop under its own weight into the oven when the wheel is rotated. After the item has been heated, it is severed from the transport web and allowed to fall under its own weight into the dispensing location. 
     In the above machine, as in many other known hot food dispensing machines, items are moving downwards as they leave the freezer compartment, and the aperture by which the items leave the freezer compartment is below the top of the compartment, often in its base. As a result, each time that the freezer compartment is opened to allow an item to be dispensed, cold air leaves the freezer compartment and is replaced by warm air. The warm air brings with it moisture which freezes and causes a build up of frost. 
     As a result, known machines for dispensing hot food have required frequent defrosting, thereby increasing their maintenance costs and reducing their efficiency. 
     OBJECT OF THE INVENTION 
     The present invention therefore seeks to provide a hot food dispensing machine in which the freezer compartment used for storing the items of food is less prone to the build up of frost. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided a dispensing machine for dispensing items of hot food, comprising a freezer compartment for storing the items to be dispensed, a microwave oven, a dispensing location and a transport mechanism for conveying items from the freezer compartment, via the microwave oven, to the dispensing location, the transport mechanism comprising a flexible transport web to which the items to be dispensed are secured and driving means for advancing the web from the freezer compartment to the dispensing location, characterized in that the microwave oven is located above and outside the freezer compartment, and the web of the transport mechanism is arranged to pass out of the freezer compartment and into the microwave oven through an opening in the roof of the freezer compartment, to avoid warm air entering the freezer compartment by convection. 
     The heating compartment in GB-A-996,039 is located within the freezer compartment. This is unavoidable in the latter proposal because the items enter the heating compartment from above and must remain frozen until such time as they are to be dispensed. Also, because the top of the heating compartment is open, heat is inevitably transferred to the freezer while an item is being heated. By contrast, in the present invention, the microwave oven is disposed entirely outside the freezer compartment. The heat generated does not therefore cause defrosting of the freezer compartment. Once the items to be dispensed have left the freezer compartment a door may close the opening at the roof of the compartment thereby effectively isolating the freezer compartment from the oven and the dispensing location. For this reason no moisture-laden warm air can enter the freezer compartment at any subsequent stage in the heating and dispensing of the item. 
     The disposition of the freezer compartment at the bottom of the machine is also particularly convenient for the loading of the food items into the freezer compartment. Also, raising the microwave oven above the freezer compartment allows the dispensing location to be arranged at a more suitable height for the user in a floor mounted machine. 
     Conveniently, the microwave oven has an inclined base that is stationary relative to the roof of the freezer compartment and a housing that can be raised from the base to permit items to be introduced into and withdrawn from the microwave oven. Because the items are being transported by a web, inclining the base avoids the need to guide the web over sharp bends. 
     It is advantageous for the housing of the microwave oven to be mechanically linked to a door closing the opening in the roof of the freezer compartment so that the opening of the door and of the microwave oven are performed in the same operation. 
     It is preferred for the web to be releasably secured to the items to be dispensed, being for example lightly glued or stapled to the items. In this way pulling of the web away from the surface of the items can be used to separate the items from the web at the dispensing location allowing the web to be wound onto a take-up reel while the items slide under their own weight to the dispensing location. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention will now be described by way of example with reference to the accompanying drawing, which is a section through a dispensing machine embodying the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the drawing, a dispensing machine 10 includes a freezer compartment 12 having a base 12a, sides 12b, a loading door 12c and a roof 12d. An opening 12e in the roof 12d of the freezer compartment can be opened and closed by a door 12f that is mounted on a housing 14a of a microwave oven 14. The housing 14a and the door 12f are movable in the direction of the arrow 15 towards and away from an inclined surface 14b that forms the base of the microwave oven. 
     The dispensing location 16 of the machine has a chute 16a with a lid 16b. The chute 16a is inclined in the opposite direction to the base 14b of the microwave oven 14 and is connected to it by a curved ramp 16c. The ramp 16c is formed with a slot 16d through which a flexible web 22 used to transport the items to be dispensed is threaded onto a take-up reel 18. 
     Within the freezer compartment 12 the items 20 to be dispensed are arranged in boxes 24. All the items within a box are secured to the flexible web 22 that is fan folded into the box 24. The connection between the web and the individual items preferably takes the form of an H-shaped plastics staple that is inserted into holes in the web 22 and the items 20. Similar staples are often used to attach labels to articles of clothing. The web 22 carries code markings that are readable by an optical decoder 26 located near the take-up reel 18. These code markings, which may be bar codes, can indicate the position of the next item on the web 22. This information can be used in controlling the mechanism transporting the items through the various stations in the machine to ensure that the microwave oven 14 is not operated when empty and to ensure that an item has been correctly dispensed. 
     In the illustrated embodiment, the take-up reel 18 acts as the advancing mechanism. The web 22 is pulled out of the freezer compartment 12, through the microwave oven 14 and over the ramp 16c by a motor driving the take-up reel 18. In this case, because the diameter of the roll on the take-up reel 18 is constantly increasing, one cannot simply rotate the reel by the same number of turns in each operating cycle. Instead the motor driving the take-up reel is controlled in dependence upon the position information read from the web 22 by the decoder 26. 
     The proposed construction of the dispensing machine has several advantages apart from the simplification of the control of the advancing mechanism. A simple automated process may be used to punch holes in the web 22 and to place the code markings on the web. This ensures that the position of every food item 20 is correctly known from reading the code markings. The spacing between articles can therefore be varied at will to accommodate items of different sizes within the same machine and using the same advancing mechanism. Furthermore, if a code marking is correctly recognised then it is known that there will be a food item 20 in the oven 14 when it is switched on and there will be no risk of damaging the oven by operating it while it is empty. Lastly, because the web 22 must come away from the item before it can be rolled onto the take-up reel 18, there is no risk of a cycle being completed without the item of food being dispensed to the machine operator. 
     The code markings may also contain information to identify the type of article supported on the web 22. Such code markings can allow the heating time in the oven and the sale price to be set appropriately. Because a web 22 will always carry items of the same type, it is not essential to repeat this information for each item and it suffices for such markings to be placed on a leader that is used to thread the web through the machine 10. Such marking of the webs avoids the need for the machine to be reprogrammed when it is replenished. 
     Because the take-up reel 18 is used to pull the web 22 through the various stations in the machine, the width of the web may be less than the width of the food items 20. Typically, a 3 cm strip of plasticised paper (spun bonded olefin--as used in the manufacture of untearable envelopes) may be used regardless of the shape and the weight of the food items. It would alternatively be possible to use a web 22 wider than the food items 20, in which case the web 22 may have sprocket holes and be driven by sprockets engaging the holes. 
     When using a narrow web to support the items to be dispensed, it is possible for the web to twist under the weight of the food item 20. However, as can be seen from the drawings, the item suspended in the freezer compartment 12 tends to hang with its center of gravity beneath the edge of the opening 12e and in this position it lies in the correct orientation to enter the oven 14 the correct way up and when it later reaches the positions in the oven 14 and on the dispensing chute 16a shown in dotted lines in the drawings it lies the right way up above the web 22. With certain types of item, such as pizzas, it is vital that they should be kept the right way up during cooking and this is achieved in the described embodiment without the need to take any special measures and by relying entirely on gravity to orient the food items 20 before they enter the oven 14. 
     The illustrated machine 10 has two boxes or cartridges 24 arranged one in front of the other when viewed from the direction of the front of the machine. The machine 10 may have several rows of boxes 24 arranged side by side. The boxes in the different rows may contain different items of food to be dispensed either in the same or a different operating cycle. For example, one item may be a hamburger and the other potato chips that are dispensed at the same time. Alternatively, the operator may be offered a choice of a hamburger, a hot dog and cheeseburger to be dispensed in different operating cycles. 
     The oven 14 is conveniently common a number of rows of boxes 24 in the freezer compartment 12, this being the less expensive construction but it would alternatively be possible to provide separate ovens 14. If items requiring different heating times are to be dispensed in the same operating cycle, it would be possible to interrupt the heating of the first item to allow the second item to be introduced at a later time into the oven 14. 
     As shown in the drawing, within a row of boxes 24 the webs 22 are connected to one another, the tail of one being connected to the leader of the next. The tail may also carry code markings to indicate that the end of the box has been reached. If the leader of the next box 24 can be connected to the tail of the previous box ahead of the end of web marker, the encoder can determine if the end of the web has been reached or if a fresh box of items has been added to the freezer compartment 12. 
     The food items are illustrated as being stored in boxes 24 that are arranged one in front of the other in the freezer compartment 12 but this makes it difficult in practice to load boxes 24 because the empty box at the back of the freezer compartment 12 must somehow be removed. In a preferred alternative embodiment, the food items are packaged in a sleeve open at both ends that can be pulled out after the items have been loaded into the freezer compartment 12 leaving only the unboxed food items in the freezer. With such a construction, fresh food items 20 can be added either in front of or beneath items already in the freezer 12. In the latter case, a spatula may be provided to raise the items 20 already present in the freezer 12 as the fresh items are being added beneath them. 
     The operation of the machine will be clear from the foregoing description of its construction. After an operator has selected and paid for a food item 20, the oven housing 14a is moved in the direction of the arrow 15 to open the oven 14 and the freezer compartment 12. The web 22 is advanced by turning the take-up reel 18 until the code markings on the web 22 indicate through the decoder 26 that the food item 20 has moved out of the freezer compartment 12 and is now located in the oven 14. The housing 14a is then lowered and the oven 14 is operated in order to heat the food item 20 or items. When the heating is completed, the oven 14 is again opened by raising the housing 14a and the web 22 is advanced until the item is pulled over the ramp 16c and separated from the web 22 at the slot 16d. The heated food item 20 is then collected by the operator from the chute 16a after the lid 16b has been opened manually. 
     It will be clear that various modifications can be made to the described machine. For example, the design of the door 12f closing the opening 12e in the roof of the freezer compartment 12 may be modified to include a flap that opens automatically as an item is pulled through the opening. This is advantageous in that the freezer compartment 12 will then not be opened unnecessarily when the oven housing 14a is raised to allow the heated food item to pass out of the oven 14 to the dispensing location 16. Also, such a flap will tend to seal around the web when the freezer compartment 12 is closed. 
     The code markings on the webs may also include other information such as a sell-by date to avoid dispensing stale items or to ensure that items are sold in the safest sequence.