WO1992006895A1

WO1992006895A1 - Heat-in carton with steam vent

Info

Publication number: WO1992006895A1
Application number: PCT/US1991/007458
Authority: WO
Inventors: David William Amburn; Jerry Allen
Original assignee: Edgewater International, Limited
Priority date: 1990-10-10
Filing date: 1991-10-10
Publication date: 1992-04-30
Also published as: WO1992007340A1

Abstract

A box or carton (180) for shipping, storing and microwave heating therein frozen pizzas (223) or the like. A punch down tab (222) is formed on the carton top panel (200) and a flap (220) is hinged in the carton directly beneath the tab. After the carton containing a frozen precooked pizza or the like has been removed from the freezer, a punch (61) is pushed down on the tab (or the carton is pushed up on a punch) punching the hinged tab down. The tab pushes against the flap and both of them become securely wedged against each other, or against each other and the carton bottom wall (202). A steam vent (234) in the top of the carton is thereby formed. Steam from the frozen pizza when it is microwave heated, can escape from the carton out this vent. After the carton has been removed from the oven, the user can tear open the tear tab (240) on the carton top and remove and eat the heated pizza directly from the carton, if desired.

Description

HEAT-IN CARTON WITH STEAM VENT

FIELD OF THE INVENTION

The present invention relates to cartons for use in heating food products in ovens. It more particularly relates to the constructions of such cartons adapted for use in vending machines wherein the carton with frozen food item, such as pizzas and the like, therein is trans¬ ported from a freezer to a microwave oven and a ter heating therein delivered to the customer for consumption of the heated food item. It further relates to systems and methods for forming steam vents in food containing cartons before placing the cartons in microwave ovens. BACKGROUND OF THE INVENTION

Many vending machines for dispensing various food or other items are known, and examples thereof include those shown in U.S. Patents 3,160,255, 4,482,078, 4,513,879, 3,416,429, 3,165,186, 2,890,644, 3,386,550, 3,534,676, 4,398,651 and 4,671,425, and British Patents 2,209,330, 2,209,331 and 2,209,332. (Each of these patents and any other patents, applications or publications mentioned any¬ where in this disclosure are hereby incorporated by reference in their entireties.) Many of these patents disclose machines which incorpo¬ rate microwave ovens for heating the food items, and many disclose means for pushing the ready food items out an access tunnel to a posi¬ tion accessible to the customer.

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, from the desired stack and passing out the opening, is then directed into a conventional microwave oven, cooked therein and pushed out to the customer. Unfortunately, this machine has a number of moving parts inside of the freezer, and because of differences in thermal expansion and contraction rates of the metals of the machine parts, 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 maehine uses round boxes which are expensive to make, dif¬ ficult to load with pizzas and difficult to cover with their round lids.

When frozen pizza or other similar food products are to be stored in a freezer and then heated in a microwave oven or the like while still in their carton, the construction of the cartons must be carefully chosen. The cartons first must be properly sealed and closed to protect the pizza or other item during transportation, shipment, and while in the freezer. On the other hand, the cartons should pref¬ erably allow for venting of steam therefrom both while in the oven and immediately after removal therefrom. The pizza, especially if it is frozen, contains a considerable amount of moisture. That moisture, under the rapid heating of a microwave oven, turns into steam vapor. If the vapor remains trapped in the carton it not only can cause the pizza to become moist and soggy but can also cause the carton or box to swell, which can cause the vending machine to jam. It is thus important to be able to easily and quickly form a steam vent in the carton after it has been removed from the freezer and before activat¬ ing the oven. This vent should be formed with minimal disturbance to the pizza or other frozen food content in the box. The vent thereby formed will also be formed so as to be securely opened with little like¬ lihood that it will accidentally close. In other words, the box must be constructed and designed so that the vent can be easily formed and easily manipulated later to an open position. Examples of cartons used for heating food products therein are disclosed in U.S. Patents 3,8"5,131 (Re. 29,185), 4,096,948, 4,260,060, 4,355,757 and 4,505,391. Containers which require a ventilating structure for ventilating the contents thereof are also known for shipping other products such as cut flowers and the like. Examples of such shipping containers are shown in U.S. Patents 4,176,745, 4,163,494, 4,331,235 and 4,339,036, and U.S. Patent 3,101,652 shows a prior art folded box construction. SUMMARY OF THE INVENTION

Accordingly, it is a principal object of the present invention to provide an improved carton construction for storing and shipping fro¬ zen food items without risk of food contamination, wherein the carton is constructed such that a steam vent can be readily formed therein for allowing steam to vent from the carton when the food item therein is microwave or conventionally heated.

Another object is to provide an improved microwave heating an vending machine for frozen pizzas or the like. This machine can handle square boxes of pizza, has few moving parts in the freezer unit thereof, is unlikely to jam, quickly and efficiently cooks the pizzas and delivers them accessible to the cus* -mer, 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 s ring a plurality of stacks of boxes of precooked frozen pizzas at approxi¬ mately five degrees Fahrenheit, and a microwave oven, for subse¬ quently cooking or heating these pizzas. The floor area of the oven is movable towards and away from the oven bottom 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 micro¬ wave oven, the floor with the cooked pizza box thereon is moved towards a delivery opening of the machine 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.

In other words, a vending machine having a freezer unit wherein at least first and second stacks of different types of packaged frozen foods, such as boxed frozen pizzas, are stored is herein pro¬ vided. The floor of the machine's microwave oven is mounted on a three-dimensional transporter. The floor is thereby controllably mov¬ able into the freezer to retrieve the bottom box of pizza from the desired stack, position the box in the oven with the floor in a sealed tight arrangement with the oven bottom opening, and thereafter move the box with the heated pizza therein to a delivery position. A motorized paddle pushes the box from the delivery position out an access tunnel to the customer.

The frozen pizza, while in its box or carton, is thus loaded, stored, transported, heated and delivered to the customer. This car¬ ton preferably has cooperating flaps on its top wall which normally close a carton top "opening" to prevent contamination of the frozen pizza during transport and storage of the boxed pizza. After the pizza box has been removed from the freezer and before being inserted in the oven, the box or carton is raised so that a fixed punch engages the flaps. (Alternatively, the carton can remain stationary and the punch moved to engage it or they can both move together towards one another.)

The top flap or tab is formed on the carton top wall by perfora¬ tions or cuts along three of its sides and a fold line on its fourth. The bottom flap is hinged in the carton interior in a normal position cov¬ ering the cuts of the top tab and directly beneath the top tab. When the punch engages and pushes down on the top tab, it pushes the top flap down along its fold line, thereby forming the opening in the car¬ ton top wall. The top tab pushes against the bottom flap until they are both wedged securely against one another and preferably also against the carton bottom wall. Steam emanating from the heated pizza can thereby vent out the opening. The carton is preferably con¬ figured and the steam vent positioned with respect thereto such that the flaps and the punch do not contact the pizza or other similarly shaped food item therein.

In other words, a box or carton for shipping, storing and micro¬ wave heating therein frozen pizzas or the like is herein provided. A punch down tab is formed on the carton top panel and a flap is hinged in the carton directly beneath the tab. After the carton containing a frozen precooked pizza or the like has been removed from the freezer, a punch is pushed down on the tab or the carton is pushed up on the punch thereby punching the hinged tab down. The tab pushes against the flap so that both of them become securely wedged against each other, or against each other and the carton bottom wall to form a steam vent in the top of the carton. Steam from the frozen pizza, when it is microwaved or otherwise heated, can escape from the car¬ ton out this vent. This carton with punch down steam vent construc¬ tion can be used for items other than frozen pizza. The items need not be frozen or even chilled, however, or even be food items. The carton need not be used in a vending machine or other environment where an automatic or mechanical punch is employed. In fact, the vent can be manually opened as with the handle end of a fork or simi¬ lar kitchen utensil. Thus, the carton can be used in commercial or residential kitchens where the cook removes the carton from the refrigerator or freezer, punches the vent open and places the carton in the microwave or other oven. No protective wrap for the carton may even be needed. With a tear open top the cooked pizza or other item can be consumed directly from this box without dirtying any dishes, making it ideal for quick snacks or those living alone.

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 and illustrating a relative positioning of the machine parts.

Figure 3 is a left side elevational view of the internal compo¬ nents of the machine of Figure 1 and illustrating the delivery tunnel thereof.

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 maehine of Figure 1.

Figure 7 is a top plan view of a first 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 having been punched.

Figure 9 is a plan view of a (paperboard) blank used to form a second pizza box or carton of the present invention.

Figure 10 is a perspective view of the blank of Figure 9 shown partially assembled into the box or carton and in an unpunched condition.

Figure 11 is a perspective view of a corner of the assembled carton of Figure 10 showing the punch opening or forming the steam vent.

Figure 12 is a view similar to that of Figure 11 showing the vent in a punched and wedged open position.

Figure 13 is a perspective view of the carton of Figure 10 after the vent has been punched open and the pizza therein cooked in the vending machine microwave oven, and illustrating the carton top being torn away to provide access to the heated pizza therein. 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 cartons or boxes 32 of prepared 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 pastas or "TV dinners". The machine 30 includes a sturdy box-like housing 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.

Figures 2-4 and 6 illustrate schematically the layout of the various machine components within the housing 34. It is seen in Fig¬ ure 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 generally out the housing 34 with the door open for restocking, through their open tops, with approxi¬ mately two hundred and forty boxes of pizza. The filtration and cool¬ ing 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 microwave 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 example in Figure 4) is then movable by a robotic three-axis transporter as shown generally at 66 controlla- bly within the machine housing 34, and as shown in isolation in Figure 5.

All machine actions, such as movement of the oven floor assembly 64 via the transporter 66, varying of cooking times (to adjust for different voltage levels), product selection, 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, however. The program of the controller 68 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 away from it 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 36, 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 (not shown) would be provided around the perime¬ ter 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 pepper- oni. 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 relocking 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 can be pepperoni and one cheese. As previously mentioned, 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 (boxed) pizzas to be removed from the bottom of both the left and right stacks. Knock down, spring loaded doors 95 (Figure 6) are provided 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 the box 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 member 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 oven magnetron 62 as a flat surface and as not having any indenta¬ tions. 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 try¬ ing 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 Fig¬ ure 4, the magnetron 62 is seen to comprise a cooling fin assembly block 62a on the oven, a smaller penthouse rectangle (or antenna) fcib on top of that and protruding down into the interior of the oven, 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 100. The block has the one-half inch high fence 96 in back and on- 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

until it is positioned under the steam vent punch pin 61 mounted in front of the oven 60. It is then . ised 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, the floor is sealed by a wire mesh type of seal relative to the oven 60 to prevent the microwave energy from escaping. After the pizza has been cooked, the oven floor 64 is lowered, moved toward the front of the machine 30 and raised to a delivery position. At the delivery position the boxed pizza 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 the customer and other unautho¬ rized persons 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. The box 32, with the heated pizza therein and when in a delivery position, extends out of the machine 30 a couple of inches, readily accessible to the cus^¬ tomer who then never has to penetrate 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 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 comprises the thin horizontal wide steel member 100, the steel plug 99, and the polycarbonate 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 so that the bottom of the pizza stack assembly is in contact with the shelf 98 and the fence 96 is immediately behind the bottom pizza box. The fence 96 works between the rails 42 holding up the edges of the hnx 32 and slides one of them, and only one of them, out onto the 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 (32) 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 62 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 for the oven 60 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 in forty-five to fifty seconds. A typical wall power supply of one hundred and ten volts and twenty amps, requires about 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 62. The microwave 60, since it is cooking precisely the same item (a seven inch diameter pizza which is approximately 0.650 inch high) each time, can be advantageously precisely tuned. These pizzas have been fully cooked at the bakery, boxed and frozen, and thus 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 hinges 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 machine 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 ver¬ tical 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. Thus, the 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-shaped 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 X 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 precisely 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 32, bring it back, up and into the pizza oven 60, and thereafter bring it down and forward to the deliv¬ ery tunnel 74. To direct the oven floor 64 to the raised left stacks 44, 46 the transporter 66 raises the oven floor above the level needed for the rig - stacks 45, 5Q, that is, above step 94. x- e construction and operation of both the freezer door 95 and the U-shaped 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-shaped assembly 120. The U-shaped 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 illustrated 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 stacked pizza boxes, the U-shaped assembly 120 raises up about one-half inch which positions the fence behind the boxes. The boxes 32 are each about three-quar¬ ters 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 positioned within two ten-thousands of an inch of the desired location. As can be appreciated, this is considerably greater accuracy than is needed.

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 protruding tab 158. 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, immediately 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.

Figures 9-13 illustrate generally at 180 an alternative preferred pizza box or heat-in carton of the present invention. This carton 180 is illustrated in a laid flat orientation in Figure 9, and comprises a blank 182 formed of paperboard or other material suitable for con¬ taining a frozen food item in the freezer 40 and for containing it as it is heated subsequently in the microwave oven 60. The blank 182 com¬ prises essentially a continuous sheet of paperboard cut, scored and perforated as shown and with an adhesive layer or glue strip 186 along the end panel 188 as shown on the right side of Figure 9. The blank 182 is formed with fold lines 190, 191, 192, 193, 194, 195, 196, 197, to define top and bottom panels 200, 202, side panels 203, 204, 205, 206 and closure taps 208, 210, 212, 214. The blank 182 is folded in a conventional manner to form a rectangular box as shown in Figure 10 with the panels 216 and 218 folding up underneath into the interior 219 of the carton 180 and the panel 203 folding on and adhering to the adhesive layer 186.

Referring to Figure 9, it is seen that a flap 220 is formed hinged along line 221 to the end wall 188 and extending out there¬ from. Similarly, a tab 222 is formed on the top panel 200 with through cuts along three sides 224, 226, 228 and a fold line 230 along the fourth. Fold line 230 is a half-cut line, cut half way through the top of the top panel 200. A pair of perforations are provided on side 226 (the side opposite to the fold line 230) to prevent accidental open¬ ing of the tab 222. When the carton 180 is assembled as shown in Fig¬ ure 10 the flap 220 is directly underneath and generally against the tab 222 as can be understood from Figure 11. With the pizza or other food item in the assembled carton 180 and the ends and sides securely closed, the pizza 223 (Figure 13) is enclosed and protected from con¬ tamination during shipping and storage. The flap 220 provides a sec¬ ondary protection as it covers the cut lines 224, 226, 228 of the tab 222.

After the box 180 containing a frozen pizza has been removed from the freezer 40 on the oven floor assembly 64, it is brought up so that the punch 61 punches down and impacts the tab 222, as best shown in Figure 11. The tab 222 and therer- the flap 220 are forced downward and wedged against not only each other but also the bottom panel 202 as shown in Figure 12. When the plunger 61 is pushed down onto the top panel the hinges of the tab 222 and flap 220 work at opposing angles (are positioned at right angles) and wedge each other open. There is with this design little if any chance that the steam vent shown generally at 234 thereby formed will accidentally close during the operation of the vending machine. Since fold line 230 is a half -cut line and adjacent (lower) paperboard fibers are ruptured dur¬ ing the punching procedure, the punched tab 222 advantageously has little, if any, "springiness" urging it to close back up. Additionally, by positioning the steam vent 234 in a corner of the square top panel of the carton 180 none of the tab 222, flap 220 or plunger 61 contacts the round pizza 223. With the steam vent 234 open, the pizza containing carton 180 is inserted in the microwave oven 60, microwave heated, removed from the oven and delivered to the customer, as previously described. The steam formed in the carton 180 from the heated frozen pizza 223 can then efficiently vent out through the steam vent 234 preventing the pizza 223 from becoming soggy and the carton from becoming distorted as the expanding steam thereby ereated attempts to escape. After the pizza 223 has been heated and delivered in the carton 180 to the customer, the customer can easily access and remove the pizza by tearing up on the tear tab 240, in a motion as shown in Figure 13 and tearing along the tear lines, weakened portions or double cut lines 242, 244 of the top panel. Double cut lines are preferred over perfo¬ rations, since contaminants may be able to enter the carton through perforations. This carton has uses aside from those in vending machines as would be appreciated by those skilled in the art. For example, the vent can be manually punched open with generally any punch tool. The cook in a residential or commercial setting can man¬ ually remove the carton from the freezer, punch the vent open and insert the carton into the oven.

In summary, the pizzas are pre-prepared, cooked, frozen and boxed. The boxes 32 or 180 are stacked according to pizza type in separate stacks in a freezer 40. A three-axis movement mechanism or transporter 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 or 180 from the desired stack 44, 46, 48 or 50 and accurately 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 or 234 has been punched open. No relative moving parts of the mechanism 66 enter the freezer 40. The pizza (223) is then rap¬ idly, accurately and consistently heated in the high intensity micro¬ wave 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 penetrate the machine 30. All activities of the machine 30 are accurately and reliably controlled, adjusted and monitored from the central computer control 68.

From the foregoing detailed description, it will be evident that there a number of changes, 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-prepared frozen pizzas, and/or the boxes or cartons can be used with different food items and/or with different ovens, such as countertop ovens. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof is limited solely by claims appended hereto.

Claims

WHAT IS CLAIMED IS:

1. A heat-in carton comprising: a top wall including an opening and a tab, said tab being movable between a normal position generally covering said opening and a punched-down position; a bottom wall spaced below said top wall; at least one side wall interconnecting said top and bot^¬ tom walls; wherein said walls define at least in part a carton interior; a flap disposed in said carton interior and hingedly attached to at least one of said walls such that said flap is movable between first and second different positions in said carton interior; wherein the first position is in said carton interior gen¬ erally along said opening; wherein when said tab is punched down from the normal position to the punched-down position said tab pushes said flap from the first position to the second position; and wherein said flap when in the second position and said tab when in the punched-down position wedge against each other and thereby lock each other and said opening in an open position, such that steam formed in said carton interior can vent out through said opening.

2. The heat-in carton of claim 1 wherein said flap when in the second position and said tab when in the punched-down position are wedged open against said bottom wall.

3. The heat-in carton of claim 1 wherein said flap is hingedly connected to said top wall.

4. The heat-in carton of claim 1 wherein said flap is hingedly connected to the top of one said side wall.

5. The heat-in carton of claim 1 wherein one said side wall includes an elongated top flap and an elongated bottom flap securable to said top flap and said cover flap extends out from said bottom flap.

6. The heat-in carton of claim 5 wherein said top flap forms an extension of said top wall and said bottom flap forms an extension of said bottom wall.

7. The heat-in carton of claim 1 wherein said top wall includes a tear away portion covering a substantial surface area thereof for providing access when torn away to the heated contents in said carton interior.

8. The heat-in carton of claim 7 wherein said tear away portion is formed using a double-cut technique.

9. The heat-in carton of claim 1 wherein said tab is posi¬ tioned in a top corner of said top wall.

10. The heat-in carton of claim 1 wherein said flap has width and length dimensions greater than that of said tab opening.

11. The heat-in carton of claim 1 wherein said tab and said flap have hinge lines disposed at generally ninety degrees relative to one another.

12. A microwave heating method, said method comprising the steps of: providing a carton which encloses therein a food item and which has a pair of cooperable tabs movable from a steam vent closed position to a steam vent open, mutually wedged open position; loading the carton with the tabs in the closed position into a freezer; thereafter, removing the carton with the frozen food item therein from the freezer; thereafter, punching the tabs to a mutually wedged open position and thereby forming a steam vent in a top surface of the carton; thereafter, microwave heating in a microwave oven the food item while in the carton and allowing steam from the heated food item to vent out the steam vent; and removing the carton with the heated food item therein from the microwave oven.

13. The method of claim 12 further comprising, after said removing step, delivering the carton with the heated food item therein to the customer.

14. The method of claim 13 further comprising tearing open the top panel of the carton and removing the heated food item therefrom.

15. The method of claim 12 wherein said punching step includes lifting the carton up against a stationary punch such that the punch pushes down on the upper of the tabs.

16. The method of claim 12 wherein the tabs include a hinged punch open tab on the top of the carton and a hinged tab in the interior of the carton and directly beneath the punch open tab, and said punching step includes punching down on the tear open flap and thereby causing it to open a steam vent opening in the top of the carton while remaining hinged thereto and to push the hinged tab down, the hinged tab and the punch open tab thereby wedging each other open.

17. The method of claim 16 wherein said punching step includes wedging the punch open tab and the hinged tab against the floor of the carton.

18. The method of claim 12 wherein the food item com¬ prises a frozen precooked pizza.

19. The method of claim 12 wherein the wedged open posi¬ tion is with both of the tabs wedged directly against each other at generally ninety degrees and against the floor of the carton.

20. The method of claim 12 wherein said removing step comprises mechanically removing the carton.

21. The method of elaim 20 wherein said punching step comprises mechanically punching the tabs.