MICROWAVE HEATING AND VENDING MACHINΕ FOR PIZZAS OR THE LIKE
BACKGROUND OF THE INVENTION
The present invention relates to vending machines having freezers for storing frozen food items and microwave ovens for heat¬ ing those items. The invention more particularly relates to such machines used or handling boxes of frozen pre-prepared pizza.
Many vending machines for dispensing various food items are known, and examples thereof include those shown in U.S. Patents 2,790,379, 2,901,964, 3,160,255, 3,653,541, 4,482,078, 4,513,879, 3,343,479, 3,416,429, 3,165,186, 2,890,644, 3,338,155, 3,386,550, 3,534,676, 4,398,651, 4,428,280, 4,592,485, 4,598,810, 4,671,425, 4,677,278, 4,687,119, 4,944,218, and 5,011,042, British Patents 2,209,330, 2,209,331, and 2,209,332, French Publication No. 2.589.607, Japanese Publication 52-50794 and German Publication DE.3738708.A1. (Each of these patents and publications and any other patents, applications or publications mentioned anywhere in this dis¬ closure are hereby incorporated by reference in their entireties.) Many of these patents disclose machines which incorporate micro¬ wave ovens for heating the food items, and many also disclose means for pushing the ready food items out an access tunnel accessible to the customer. Examples of positioning tables in non-vending machine environments are shown in U.S. Patents 3,124,018, 4,317,560, 4,378,709 and 4,672,859.
One known pizza vending machine is available from the Ameri¬ can Pizza Company, a corporation of Nevada. See Italian Patent No. 59465.B/86, which issued October 29, 1986. This machine allows the toppings to be selected by the customer, placed on a fresh crust and baked in an infrared oven for three minutes or so. Maintenance of
this machine is labor intensive, however, as it must be cleaned fre¬ quently and fresh ingredients added daily.
Another relatively recent pizza vending machine is that avail ¬ able from Nouveau Vend International, Inc. of Palm, Pennsylvania and Nouveau Foods, International, Inc. of Spring City, Pennsylvania, under the mark PIZZA CHEF. This vending machine has a large cylinder positioned in a freezer, and the cylinder in turn has round chambers into which small round pizza boxes are inserted. A selector button allows the cylinder to be rotated to align the desired stack with the opening. The boxed pizza is then directed into a conventional micro¬ wave oven, cooked therein and pushed out to the customer. Unfortu¬ nately, this machine has a number of moving parts inside of the freezer, and because of differences in thermal expansion and contrac¬ tion rates of the metals, the machine appears susceptible to jamming. Loading this machine is also difficult. The cylinder or canister mech¬ anism has to be tilted forward, loaded with approximately one hun¬ dred and twenty to one hundred and fifty pounds of pizzas and then tilted back up and pushed back in. This is a difficult maneuver requir¬ ing more strength than many operators have. A further problem is that this machine uses round boxes which are expensive to make, dif¬ ficult to load with pizzas and difficult to cover with their round lids. SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the present invention to provide an improved microwave heating and vending machine for frozen pizzas or the like.
Another object of the present invention is to provide such a machine which can handle square boxes of pizza, has few moving parts in the freezer unit thereof, is less likely to jam, quickly and efficiently cooks the pizzas and delivers them accessible to the cus¬ tomer, and is less susceptible to mischief and/or damage.
Directed to achieving these objects, an improved frozen pizza microwave heating and vending machine is herein disclosed. This machine includes within its cabinet walls a freezer unit, for holding a plurality of stacks of boxes of precooked frozen pizzas at approxi¬ mately five degrees Fahrenheit, and a microwave oven for cooking these pizzas. The floor area of the oven is movable towards and away
from its opening by a three-dimensional mechanical transporter to which it is affixed. The transporter inserts the oven floor into the freezer unit where it retrieves the bottom box from the desired stack, removes the box from the freezer unit, positions it beneath the microwave oven and moves it up so that the floor is sealed tight in the bottom opening of the microwave oven. After the pizza has been cooked in the microwave oven, the floor with the cooked pizza box thereon is moved towards a delivery opening and then is pushed by a motorized paddle through an access tunnel to the customer. When the oven is hooked up to a two hundred and twenty volt service, the pizza is cooked from frozen to serving hot in only about thirty seconds, and the entire cooking and vending operation takes less than a minute.
Other objects and advantages of the present invention will become more apparent to those persons having ordinary skill in the art to which the present invention pertains from the foregoing description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a front elevational view of a machine of the present invention with the door thereof in the closed position.
Figure 2 is a perspective view of the machine of Figure 1 with the door in an open position.
Figure 3 is a left side elevational view of the internal compo¬ nents of the machine of Figure 1.
Figure 4 is a front elevational view showing the layout of the components of the machine of Figure 1.
Figure 5 is a perspective view of the three-axis transporter of the machine of Figure 1 and shown in isolation.
Figure 6 is an enlarged elevational view showing a pizza box being mechanically and automatically retrieved from the freezer of the machine of Figure 1.
Figure 7 is a top plan view of an unpunched pizza box of the present invention and for use in the machine of Figure 1.
Figure 8 is a side view of the box of Figure 7 after being punched.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the drawings there is illustrated therein generally at 30 a microwave heating and vending machine of the present inven¬ tion. Although it is especially adapted for handling boxes 32 of pre¬ pared frozen pizzas, other types of frozen prepared foods items as would be apparent to those skilled in the art can be used. Examples of such other heatable and deliverable products are lasagnas, other pas¬ tas or "TV dinners". The machine 30 includes a sturdy box-like hous¬ ing 34 supported on four legs 36 approximately six inches above the support surface and with an open front which can be closed when the door 36 hinged thereto is shut and locked. All of the components of the machine 30 are thereby protectively enclosed within this housing 34.
Each of the figures and especially Figures 2-4 and 6 illustrate schematically the layout of the various machine components within the housing 34. It is seen in Figure 2 that the machine 30 includes a freezer chamber 40 enclosing therewithin stacking rails 42 for four stacks 44, 46, 48, 50 of pizza boxes in a square relation and with the outer two stacks 48, 50 extending a distance further down than the inward two stacks 44, 46. The pizza stacks can be slid forward gener¬ ally out the housing 34 with the door open for restocking through their open tops with approximately two hundred and sixty pizzas. The filtration and cooling evaporator for the freezer unit 40 is shown at the bottom of the stack to the left at 54 and the condenser and compressor assembly to the right at 56. A novel mierowave oven construction 60 is positioned about midway up the left hand wall and has an open bottom. The oven floor assembly 64 (as shown for exam¬ ple in Figure 4) is then movable by a robotic three-axis transporter as shown generally at 66 controllably within the machine housing 34, and as shown in isolation in Figure 5. All machine actions, such as move¬ ment of the oven floor assembly 64 via the transporter 66, varying of cooking times (to adjust for different voltage levels), product selec¬ tion, coinage control, and maintenance diagnostic and telemetry are controlled from a central computer control shown in the upper left hand corner of Figure 2. The controller 68 will preferably be only the size of a routine small computer card. The controller 68 program
monitors the line voltage so that the cooking times are adjusted dependent upon the available energy. A transformer power unit 70 (Figure 2) for the machine is positioned beneath the computer control. The boxed pizza 32 after it has been cooked in the oven 60 is moved thereaway on the oven floor assembly 64 and then pushed out by a motorized paddle 72 (Figure 3) accessible to the customer through the tunnel 74 which communicates with the opening 76 in the door as shown in Figures 1 and 2.
Referring to Figure 1 the solid steel front machine door 36 is shown having centrally disposed thereon a brick oven shaped cutout 78 for advertising and/or explanatory graphics or the like. It is antic¬ ipated that lighting would be provided around the perimeter of the cutout 78 both for ornamentation and for ease of reading the graphics therewithin. At the top left is the dollar bill acceptor 80, and the units directly below are the select buttons 82, 84 for selecting the different desired pizza type, such as cheese or pepperoni. Generally on the left and below the cutout 78 is the slot 76 out through which the boxed cooked pizzas 32 are delivered by the paddle 72. The coin handler 86 is positioned at the top at the right of the cutout area 78 and the lock 88 for opening the machine, servicing it and subsequently locking it is directly therebeneath. The double square at the bottom right is the customer coin return 90.
The four stacks of pizzas 44, 46, 48, 50 can be independently targeted to serve one kind of pizza or another; by setting a switch, the controller 68 is advised which kind of pizza is in each stack. For example, two of the stacks can be cheese pizzas and the other two pepperoni, or three pepperoni and one cheese. As previously men¬ tioned, the leftmost stacks 44, 46 are shorter than (or raised higher than) the rightmost stacks 48, 50 since pizzas are removed from the bottom of the freezer unit 40 and the small offset 94 thereby defined allows for the pizzas to be removed from the bottom of both the left and right stacks. Knock down, spring loaded doors 95 (Figure 6) are positioned at the bottom inside corners of each of the stacks. The oven floor 64, when its movement is so directed by the controller 68, is moved by the transporter 66 in through the door 95 to retrieve the bottom box of pizza from the proper stack. The oven floor 68 has a
small fence 96 along its forwardmost (rightmost) edge which is raised up behind the bottom pizza box and drags it off the bottom of the stack (44, 46, 48 or 50) as the oven floor 64 is moved inward or to the left.
A three-quarter inch thick plastic shelf 98 on which the pizza box 32 sits and which is invisible to microwave radiation and a steel plug 99 which on sealing presents an even floor surface thus tuning the oven cavity and acting to entrap microwave radiation, are mounted on top of the oven floor 100. Member 100 is about eight and a half inch square. Between the member 100 and the plastic spacer 98 are the radiation seal and the oven floor. The metal plug 99 in the oven floor cutout allows the oven floor 100 to be seen by the magnetron as a flat surface and as not having an indentation. The plug 99 is essentially twice as thick as the oven floor — one thickness allows for it to be presented as a flat floor and the other allows for space for the radiation seal. Thus, any radiation trying to escape must make two right angle turns. The pizza thereon appears, to the magnetron 62 of the oven 60, to be suspended three-quarters of an inch off of the oven floor 99. Referring to Figure 4 the magnetron 62 is seen to compromise a cooling fin assembly block 62a on the oven, a smaller penthouse rectangle 62b on top of that and protruding down into the interior of the oven is a three-quarter inch magnetron dome 62c. Thus, the plastic spacer 98 raises the boxed pizza up off the metal floor portion 100 (Figure 6) so that the microwave energy sees it better and reduces the likelihood of hot spots being produced. The plastic spacer 98 comprises a polycarbonate slab that has been milled to have a small back or fence 96 to it, which then positions the pizza approximately three-quarter inch off of the metal oven floor plug 99. The block has the one-half inch high fence 96 in back and one-quarter inch fences on two sides.
The movement of the pizza box 32 thus is that it is first pulled out of the freezer 40 and moved back until it is lined up side-by-side as viewed from the front of the machine 30, then it is moved back until it is positioned under the steam vent punch pin 61 mounted in front of the oven 60. It is then raised up to punch the self -locking steam box vent in the pizza box 32, as will be explained in detail
later. It is then moved down and back, and then raised up into the oven 60. When in position in the oven floor opening, it is sealed by a wire mesh type of seal relative to the oven 60 to prevent the micro¬ wave energy from escaping. After the pizza has been cooked, the oven floor assembly 64 is lowered, moved toward the front of the machine 30 and raised to a delivery position. At the delivery position the pizza box 32 is pushed by the motorized rotary paddle 72 out through the tunnel 74 and accessible to the customer through slot opening 76. The paddle 72 pushes the pizza box 32 entirely through the tunnel 74 so the rear door 104 (Figure 3) thereof closes before the front door 106 opens. This denies people access to the interior of the machine 30. In other words, the paddle 72 pushes the box 32 clear of the back door 104 before it opens the front door 106, and then the paddle is withdrawn, the back door closes and the customer pulls the box from the machine 30. When the box 32 is clear of the front door 106, the front door closes. Even if the front door 106 is jammed open, the back door 104 would be closed, thereby denying the customer or other unauthorized persons access to the interior of the machine 30. Thus, the box 32, with the heated pizza therein and when delivered, sticks out of the machine 30 a couple of inches readily accessible to the customer who then never has to enter the machine, not even with his finger tips.
Figure 4 illustrates the door mechanisms for retrieving the pizza boxes 32 out of the stacks 44, 46, 48, 50. The outside edges of the stacks are shown by the four vertical rectangles which represent four three-quarter inch angled rails 42. The pizza boxes 32 are loaded from the top of these rails 42, as previously mentioned. The oven floor assembly 64 is illustrated in Figure 4 in position to retrieve the bottom box of pizza from a rightmost stack 50. The oven floor assembly 64 is a thin horizontal wide steel member 100, the steel plug 99, and the plexiglass shelf 98 with the fence 96 in the back or on the right of Figure 4. The pizza boxes 32 are held only at their corners by the bent rails 42 and the areas between the corners are generally clear. The floor 64 is pushed into the freezer 40 and then it raises up about a one-half inch to where the bottom pizza box is in contact with the shelf and the fence 96 is immediately behind it. The fence
works between the rails 42 holding up the edges of the box 32 and slides one of them, and only one of them, out and on to shelf 98
As soon as the box 32 has been withdrawn from the freezer 40 it is moved all the way over to the left-hand side of Figure 4, even with the microwave oven 60, as seen in Figure 4, directly in the left to right sense under the oven. The oven floor assembly 64 is then moved back (into the page of Figure 4) until it is positioned below the bottom opening 62 of the oven 60. It then travels up thereby placing the boxed pizza in the oven 60 and sealing the bottom of the oven with an R.F. seal. The bottom of the oven 60 is thereby sealed against radiation leakage and the boxed pizza is enclosed within the oven. The two thousand watt magnetron is actuated, and the pizza is heated.
The magnetron 62 is positioned in the top corner of the oven 60 and extends down with dome 62c through the oven ceiling into the interior of the oven. The magnetron 62 located in the corner of the roof or ceiling of the oven 60 is oriented with respect to the pizza so that the pizza cooks uniformly. No waveguide as is typically provided in a conventional microwave oven is thus needed. The oven 60 is preferably ten inches wide and long and six to ten inches high. To further improve the heating efficiency, the geometry of the inside of the oven 60 can be adjusted, reflectors added, the location of the magnetron or the pizza altered as would be apparent to those skilled in the art from this disclosure.
The preferred power supply is a two hundred and twenty volt service which can heat the pizzas in thirty seconds or less. If a thirty amp, one hundred and ten volt service is used then the pizza is cooked between forty-five and fifty seconds. A typical wall power supply of one hundred and ten volts and twenty amps, requires about a one and a half minutes to cook the pizza. The length of time to cook the pizza is directly related to the amount of energy provided to the magnetron. The microwave 60 since it is cooking precisely the same item each time — a seven inch diameter pizza approximately 0.650 inch high — can be advantageously precisely tuned. The pizzas have been fully cooked at the bakery, boxed and frozen so that all the
microwave oven 60 is doing is warming them up, that is, bringing them to a hot consumption temperature.
The doors 95 to the freezer 40 are spring loaded, knock down doors hinged by hinge 112 at the bottoms thereof and which are pushed open when the oven floor assembly 64 is inserted into the freezer 40 and which spring shut after the oven floor and pizza box 32 thereon have been removed from it. The freezer 40 is surrounded by insulation 114. The assembly portion 120 of the transporter 66, the portion which holds the oven floor assembly 64, is shaped like a U lying on its side when viewed from the front and as can be seen in Figures 4 and 6. In other words, the assembly 120 comprises spaced horizontal upper and lower members 123a, 123b and a left vertical member 126 connecting them. This U shaped configuration allows the oven floor 64 to retrieve pizzas from any of the four stacks 44, 46, 48, 50 including the raised inside ones 44, 46. The oven floor assembly 64 is secured to upper member 122 by glue and/or screws. This assembly 120 is free to move front and back, left and right, and up and down, that is, in each of the X, Y and Z directions.
The transporter 66, which essentially comprises three linear actuators, is shown in isolation in Figure 5 wherein the three riding rails systems shown generally at 122, 124 and 126 for each of the directions are illustrated. For the up and down movement two rails 122a and 122b are provided since they must carry the weight of the assembly 120 including that of a pizza box 32, the transporter axes 124, 126 and the associated motors 132, 134, 136. The double rail 122 moves the assembly 120 up and down in a Z direction; the X direction extends out of the page; and the Y direction runs along the page. The assembly 120 is mounted on a small four inch block 130 as shown in Figure 5 and the U assembly would be open towards the right hand side of the page. The individual stepper motors 132, 134, 136 move this block along each of the axes or rails. The stepper motors 132, 134, 136 eliminate the different linkages apparently needed when DC actuator motors are used in known vending machines. The rectangle in the back with the motor mounted on top and the two rails on the sides move the assembly up and down and are positioned against the left side of the machine. Less than halfway up, the X member is
mounted and it runs from the front of the machine to the back, that is from left to right; its motor 136 is at the right side. The Y direction is positioned towards the right side of the X member, its motor 134 is back against the Y member, and it moves the block 130 from the motor end to the floor end where it enters into the backmost freezer. The transporter 66 thus allows the oven floor assembly 64 to be pre ¬ cisely positioned where necessary inside of the cabinet or housing 34 including covering the oven floor cutout. In other words, the oven floor assembly 64 can be directed to enter the freezer 40, retrieve a boxed pizza, bring it back, up and into the pizza oven 60, and thereaf¬ ter bring it down and forward to the delivery tunnel 74. The trans¬ porter 66 to direct the oven floor assembly 64 into the raised left stacks 44, 46 raises the oven floor above the level needed for the right stacks 45, 50, that is, above step 94.
The construction and operation of both the freezer door 95 and the U-shape assembly 120 are better depicted in Figure 6. The four inch block 130 that sits on the Y axis is shown and on top of that is mounted the U assembly 120. The U assembly 120 then travels over and under the lower insulation layer 114 into the freezer 40. As the oven floor assembly 64 is inserted into the freezer 40 it impacts the door 95, which is folded down about hinge 112 into the area provided by the insulation cutoff triangle shown at 140 (Figure 6). The door 110 is positioned in the down or open position in Figure 6. As the U-shaped assembly 120 with the oven floor 64 secured thereon is pushed further into the freezer 40, or to the right of Figure 6, and the small fence 96 is clear of the stack pizza boxes, the U-shaped assem¬ bly 120 raises up about one-half inch which positions the fence behind the boxes. The boxes 32 are each about three-quarters inch thick or high and the bottom half inch of the box will thus then have the fence 96 behind it. The U-shaped assembly 120 is then withdrawn from the freezer 40, or to the left of Figure 6, and when it clears the door 95, the door is spring biased closed thereby closing the freezer. Thus, there are no relative moving parts of the U-shaped assembly 120 inside of the freezer 40 and the oven floor assembly 64 can be posi¬ tioned within two ten thousands of an inch which is a considerably greater accuracy than is required.
To prevent steam from forming in the box 32 as the pizza is being heated in the oven 60 and to thereby soften the pizza and dis¬ tort the box, a steam vent 148 is punched in the box after it has been removed from the freezer 40 and before it is inserted in the oven 60. Referring to Figure 7, an unpunched vent member 150 is formed in one corner of the box 32 during the box formation. The member 150 has three of its edges 152 cut and the fourth edge 154 only scored to prevent accidental opening. The front of the box 32 is folded up and glued and attached to it is a tab 158 which sticks out. It also has a score line 160 and when folded up it is directly under the cutout. When the member 150 is punched from the top, the cut 152 on the three sides opens downward until it catches in the score 160 whereby it locks itself, thereby forming the self-locking steam vent 148, as shown in Figure 7. Thus, just before the boxed pizza 32 enters the oven 60, the oven floor assembly 64 moves over under the puncher 61 (the smaller nipple member under the oven) and raises up, punches the vent member 150, travels down and then travels under and into the oven as shown by the arrows in Figure 4. The score 160 on the bottom flap 158 thus effects the locking action by engaging the for¬ ward edge of the top flap member 150.
In summary, the pizzas are pre-prepared, cooked, frozen and boxed. The boxes 32 are stacked according to pizza type in separate stacks in a freezer 40. A three-axis movement mechanism or trans¬ porter 66 with the oven floor assembly 64 of the microwave oven 60 secured thereto enters the freezer 40 through door 95, extracts the bottom pizza box 32 from the desired stack 44, 46, 48, or 50 and accu¬ rately positions the oven floor assembly 64 in a sealed tight relation in the bottom opening of the oven 60 with the box on the oven floor assembly and in the oven, and after the steam vent 148 has been formed. No relative moving parts of the mechanism 66 enter the freezer 40. The pizza is then rapidly, accurately and consistently heated in the high intensity microwave oven 60. The oven floor assembly 64 is thereafter moved down and away from the oven 60 and the box of heated pizza pushed by paddle 72 out a delivery tunnel 74 without customer assistance or the need for the customer to pene¬ trate the machine 30. All activities of the machine 30 are accurately
and reliably controlled, adjusted and monitored from the central com¬ puter control 68.
From the foregoing detailed description, it will be evident that there a number of change^ adaptations and modifications of the present invention which come within the province of those skilled in the art. For example, the present vending machine can be adapted to handle heatable and deliverable products other than boxes of pre-pre- pared frozen pizzas. However, it is intended that all suph variations not departing from the spirit of the invention be considered as within the scope thereof is limited solely by claims appended hereto.