BACKGROUND OF THE INVENTION  
       [0001]     Fabricated snack food products such as potato chips, potato crisps, tacos, tostadas and the like were commonly formed and fried while captive between intermeshing, male and female, pairs of molds. The molds with the uncooked products captive therein were immersed in hot cooking oil. In this manner the products were compelled to take the shape of the molds while undergoing heat treatment or cooking. Systems that operate in this general manner were disclosed and claimed in the following US patents owned by Heat and Control, Inc.: U.S. Pat. Nos. 6,467,401; 4,554,865 and 4,510,165. Notable for these systems were certain mechanical characteristics including the high costs of the molds, complexity of ensuring that the molds in operation mesh exactly, the need for precise timing of the incoming products with respect to the molds, high maintenance costs and a relatively poor product throughput to oil volume ratios in the systems.  
         [0002]     In an alternative prior art system, “free-form” fabricated potato chips or crisps were cooked while retained between a flat, wire mesh conveyor belt and rows of concave, upward facing, single curve molds. The chips thus formed to the shape of the molds by the upward flow of cooking oil through the mesh of the flat belt and by buoyancy of the chips as they were cooked. Benefits of this prior art system were the reduction of complexity in the fryer design compared to the closed mold design and relatively low product throughput to oil volume ratios. Perceived limitation on this system included its suitability for only relatively shallow product shapes with a simple curvature. It was not suitable for compound curve shapes or for deeper shaped products such as tacos and the like. Further, loss of chip orientation or misalignment with respect to the molds while cooking produced misshapen chips and consequent chip rejects. Consistent chip orientation in the cooking process is especially important to enable assemblage of the chips for subsequent packaging. Double chips, partially uncooked, and misshapen “folds” or “long hom” chips are to be avoided in the desired high quality chip product.  
         [0003]     Another observation on this prior art process was that at discharge cooked chips were, at times, seen to stick to the molds and fail to release via gravity and could, unless detected, re run through the cooker a second time producing an unacceptable product. A further observation was at discharge from the cooker the curved chip was oriented in the upward facing position and residual cooking oil would reside along the upper surface. Removal of this residual oil by a blast of air or steam was frequently necessary to produce a chip with the desired oil content.  
         [0004]     Following discharge from the cooker and onto a take away conveyor the upward facing curved chip required a “flop over” step to enable the chips to “shingle” or nest for packaging. As many as 8 or 10 quality control persons were seen stationed at the discharge end of a high volume cooker to pluck away misshapen chips and to ensure the cooked chips maintained the desired orientation for seasoning and packaging.  
         [0005]     Another alternative “free form” system was disclosed in U.S. Pat. Nos. 6,067,899 and 6,558,724 by the inventors Andrew A. Caridis, et al., for cooking of a wide variety of food products as they were passed under one or more continuously flowing curtains of hot cooking oil. There the products were carried in situ on a conveyor belt extending beneath the flowing curtains of oil and thus were cooked. This system had a relatively favorable ratio of oil volume to product throughput and was mechanically much less complex than the systems discussed above. Thus it is an important objective of this invention to apply the flowing oil curtain technology to the forming, while cooking, of both simple and complex product shapes such as potato chips, potato crisps, and corm based products such as taco shells and tostada shells.  
       SUMMARY OF THE INVENTION AND OBJECTS  
       [0006]     In summary this invention includes a method of forming food products in the absence of male and female mold pairs while simultaneously cooking the product with flowing cooking oil in the absence of a cooking oil bath and includes the steps of providing a supply of flat, discrete pieces of uncooked food product and conveying them along a processing path; providing in said path a conveyor having an interlinked set of form surfaces; moving the pieces of food product unto the form surfaces while the conveyor in moving along the process path; providing above the conveyor a supply of cooking oil and flowing the oil downwardly in a curtain for enveloping the food product disposed upon the form surfaces such that the weight and kinetic energy of the oil flowing oil form the food product into the desired configuration while the enthalpy of the oil cooks it; and then removing the formed product from the form surfaces for transfer to a subsequent treatment.  
         [0007]     The invention also resides in apparatus for the efficient forming and cooking of food products using cooking oil dispensed in controlled, overflow curtain spillage onto the products and includes an endless conveyor equipped with an interconnected set of mold bodies having form surfaces movable along a processing path between product loading and unloading stations; product loading means for applying flat formed discrete pieces of food products onto the form surfaces; cooking oil reservoirs arranged above the conveyor and having weirs over which oil in flows in a continuous curtain so as to heat the molds, form the products and cook the products residing on the form surfaces; a pan for catching cooking oil is provided with a drain coupled to an oil recirculation and reheating system serving to resupply the oil reservoirs and provisions for dismounting the cooked and formed products from the molds at the product unloading station.  
         [0008]     An important object of the present invention is to provide a highly efficient system for simultaneously forming and cooking a variety of food products without their submergence in cooking oils or entrapment within molds.  
         [0009]     Another object of the invention is to provide a method for forming while cooking either simple or complex shapes of food products, in a continuous process, such as taco shells, tostada shells and the like.  
         [0010]     Yet another object is to provide improved apparatus to enable food product forming while cooking in a cascade or curtain of cooking oil, the apparatus assuring an improved ratio of cooking oil volume to product throughput.  
         [0011]     Further objects and advantages of the invention will appear from a consideration of the illustrative drawings taken in connection with the following detailed description.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a general flow chart showing the sequence of operations in preparing a fabricated snack food product of complex shape starting from the dough mixing through to the packaging operation;  
         [0013]      FIG. 2  is a schematic view in elevation of the product input end of a fryer adapted to carry out the process and principles of the present invention;  
         [0014]      FIG. 3  is a transverse, fragmentary sectional view taken along the lines  3 - 3  of  FIG. 2  and depicting the overhead spillage of hot cooking oil onto the products supported by the molds;  
         [0015]      FIG. 4  is a fragmentary longitudinal view of the product discharge end of the conveyor and depicting discharge of the cooked and formed products by means of a vacuum transfer conveyor;  
         [0016]      FIG. 5  is a transverse sectional view taken along the lines  5 - 5  of  FIG. 4 ;  
         [0017]      FIG. 6  is another fragmentary longitudinal view of another form of conveyor included in the present invention and depicting the discharge of the cooked and formed products;  
         [0018]      FIG. 7  is a transverse sectional view taken along the lines  7 - 7  of  FIG. 6  and depicting a two-part mold in the closed condition, while  
         [0019]      FIG. 8  is a view like  FIG. 7  but taken along the lines  8 - 8  of  FIG. 6  and depicting a two-part mold in the open condition for releasing formed and cooked product from the mold;  
         [0020]      FIG. 9  is a view like  FIG. 6  but depicting another arrangement for the discharge of the products onto a conveyor belt for further treatment;  
         [0021]      FIG. 10  is a view like  FIG. 6  but depicting yet another arrangement for releasing and discharging the cooked and formed products from the molds;  
         [0022]      FIG. 11  is a view like  FIG. 6  but depicting still another arrangement for the handling the formed products with respect to the molds;  
         [0023]      FIG. 12  is a transverse sectional view taken along the lines  12 - 12  in  FIG. 11 ;  
         [0024]      FIG. 13  is a perspective view of a group of double curvature or saddle shaped molds with curvilinear shaped product supported therein;  
         [0025]      FIG. 14  is an elevation view of the molds of  FIG. 13 ;  
         [0026]      FIG. 15  is a perspective view of a group of inverted Vee shaped molds useful for forming and cooking tacos and the like from tortillas which are shown mounted on four of the molds; and  
         [0027]      FIGS. 16-18  are views respectively like those of  FIGS. 6-8  and depicting another form of two part mold with a medial finger element active to remove cooked product from the molds.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     Referring to the drawings, there is shown in  FIG. 1 a  schematic diagram which enables the practice of the invention and includes dough and mixing stage  11 , a sheeting and cutting stage  12 , a forming and cooking stage  13 , a product de-oiling stage  14  and a packaging or other final processing stage  16 .  
         [0029]     The dough mixing stage  11  is significant in that it has been found that the process of this invention is most successfully applied to “fabricated snack food products” such as potato chips or crisps and Mexican style snack foods made from a corn masa including shells for tacos, tostadas and similar items. To that end recipes well known in the field may be successfully adopted and adjusted as experience dictates so as to produce a potato dough or a corn masa, or a wheat based dough as the case may be. When the dough or masa has reached the desired consistency for the subsequent step of sheeting and cutting it is passed by conveyor (not shown) to stage  12 , cutting and sheeting of the starting materials. On the other hand, the subject process and associated apparatus are well adapted to forming and cooking relatively thin starting materials such as sliced potatoes, plantains and apples. In such instances a slicing stage replaces the dough mixing stage  11 .  
         [0030]     The sheeting and cutting stage  12  may employ known equipment such as the sheeter machines disclosed in Andrew A. Caridis, et al U.S. Pat. Nos. 5,626,898 and 5,580,583 assigned to Heat and Control, Inc. of Hayward, Calif., or such as conventional bakery sheeting and rolling machines having more than 2 rolls. There the dough or masa is sheeted, that is, formed or compressed in the nip between counter rotating pinch rolls to a desired thickness in the range of from about 0.025 inches to about 0.075 inches [0.635 mm. to about 1.905 mm.] or more as the product application dictates. As disclosed in the above mentioned patents, the sheeted material may be cut to a desired shape in the sheeter machine and then discharged, typically in aligned formation onto a conveyor belt  17 ,  FIG. 2 . The sheeted products are preferably cut in a generally circular shape to a diameter in the range of from about 2 inches to about 7.5 inches. Alternatively, other shapes may be adopted for the subject process by making appropriate adjustments to the sheeter-cutter  12  such as rectilinear (diamond, square, polygonal etc.) oval or elongate shapes. The desired finished shape of the formed and cooked product determines the selection of the flat pre-cooked product emanating from the sheeter and cutting stage  12  and delivered by the conveyor belt  17  to the forming and cooking stage  13 ,  FIG. 2 . By appropriate regulation of the speed of the conveyor belt  17  with respect to the delivery of product from the sheeter  12 , the flat sheeted and cut products  18  will be arrayed on the conveyor belt  17  in rows with the individual pieces evenly spaced apart both laterally and longitudinally, with no overlap. This is to assure that the cut pieces  18  engage and ride upon the form surfaces  19  symmetrically with respect to an imaginary longitudinal plane passing through the high points of the form surfaces  19  as clearly shown in  FIG. 3 .  
         [0031]     Referring more particularly to the forming and cooking stage  13  as illustrated in  FIGS. 2-4 , and  15 , the form surfaces  19  are the exterior surfaces of convex mold bodies  20  that are mounted upon an endless conveyor  21  powered to move in the direction of the arrow  22 ,  FIG. 2 , between a product input or loading station  23  to a product discharge station  24 ,  FIG. 4 . Shown in broken lines in  FIGS. 2 and 4  are the sprockets  26  conventionally provided in laterally spaced apart relationship for an endless conveyor  21 . Reeved over the sprockets  26  are endless chains  27  having laterally extending cross rods  28  carried thereby as indicated in  FIGS. 3 and 5 . The convex mold bodies  20  are mounted on the cross rods  28  coupled to the endless chains  27  as indicated in  FIG. 3  and as so mounted in side-by-side relationship are equipped to individually pivot or rotate as the cross rods  28  carried by the chains traverse the sprockets  26  at the unloading station  24 , clearly shown in  FIG. 4 . Thus the mold bodies  20  shift from a longitudinally aligned array in the horizontal portion of the conveyor top run to a segmented or opened or fanned configuration at the product discharge station  24 . This articulation of the mold bodies on the endless conveyor enables easy removal of the cooked and formed products to be described in more detail below.  
         [0032]     The number of mold bodies  20  mounted laterally on the cross rods  28  is a function of the overall design of the system and can vary from as few as 1 or 2 to as many as 22 or more, see for example FIGS.  13  and  15 . It will be understood that each mold body  20  provides the form surface  19  for carrying the product  18  during the cooking and forming operation. The form surface may be shaped to a single curvature as indicated in  FIGS. 3, 7  and  8  such as for an application to produce a formed potato chip. As illustrated in  FIGS. 13 and 14 , the form surface  19  can also be shaped concave using a double curvature or saddle shaped mold body  20 ′ (20 prime). This would serve as for an application to produce a saddle shaped product as is common to certain brands of fabricated potato chips. Considering now  FIG. 15 , in an application of the present invention to produce taco shells from tortillas, the mold bodies  20  are shaped to a convex Vee shape with a curved apex. Both the convex and concave mold bodies may be formed from smooth or rough or textured surfaced sheet metal or plastic material as indicated in  FIGS. 3 and 4 , or from a perforated sheet metal or plastic material as shown in  FIGS. 13-15  or from a convex surfaced embossed metal or plastic material. When the metal or plastic mold body is perforated “inside out” the exterior form surfaces  19  have “tooth” that assists in maintaining the position of the product with respect to the mold during forming and cooking.  
         [0033]     We disclosed in our U.S. Pat. Nos. 6,558,724 and 6,061,899, titled “Cooking by enrobing through controlled curtain spillage” systems for delivering hot cooking oil onto products carried on conveyor belts. This application carries forward the new use of certain principles shown in those patents.  
         [0034]     More particularly and referring now to  FIGS. 2 and 3 , a cooking oil heating, controlling and delivery system  31  is provided and includes a fryer pan  32  equipped with an oil sump  33  connected by a conduit  34  to a circulation pump  36  that in turn furnishes oil through a conduit  37  to a heat exchanger  38 . Suitable controls (not shown but well known in the art) are included in the system  31  to set and maintain selected cooking oil temperatures and the volume of oil delivery within the system as well as the supplying of make up cooking oil as needed so that the oil volume, temperatures and oil delivery rate are all selectable for operational purposes of the system  31 .  
         [0035]     We prefer cooking with the cooking oil at temperatures within the range of about 290° to about 390° F. [143° to 199° Celsius] depending upon the product type or configuration and the cook time. We have also found it desirable to pre heat the mold bodies  20  to approximately oil operational temperatures prior to loading products  18  on the mold bodies  20 . This step lessens product sticking and facilitates the easy removal of the cooked and formed products  18 ′ from the mold bodies.  
         [0036]     Shown in  FIG. 2  are two exemplary oil reservoirs  39  and  41  mounted above the top run of the conveyor  21 . Each reservoir is equipped with a manifold  42 , both being supplied with cooking oil at a controllable rate from the heat exchanger  38  through conduits  43 . The reservoirs  39 ,  41  are each configured to include a discharge weir or lip  44  over which oil spills in a smooth downward flowing curtain onto the mold bodies  20 . With the object of minimizing turbulence developing in the reservoirs  39 ,  41 , the manifolds  42  are equipped for discharge of cooking oil below the weirs  44  as well as below the nominal oil level in the reservoirs. Suitable oil delivery apertures (not shown) are provided on the manifold bottom walls for this purpose. With this configuration of reservoir and weir, as well as from the control of oil flow in the system  31 , cooking oil flows in a smooth curtain  46  downwardly as indicated by the arrows  47  unto the food products  18 ,  FIG. 3 .  
         [0037]     We prefer the oil free fall a distance from the weir lip to the product to be in the range of about 0.5 inches to about 4 inches [12.7 mm. to about 101.6 mm]. Further the cooking times, that is the time the products are first mounted on the form surfaces to the moment of their discharge at the unloading station  24 , to be in the range of about 15 seconds to about 90 seconds. We believe it desirable in certain particular applications to have several reservoirs beyond the two exemplary reservoirs  39 ,  41  illustrated in  FIG. 2 .  
         [0038]     Referring to  FIGS. 4 and 5 , there is provided at or near the product unloading station  24  vacuum assist means  51  to assist smooth product release and removal from the molds  20 . This includes an enclosure  52  arranged over and through which the rows of mold bodies  20  traverse. The bottom  53  of the enclosure is provided with an array of openings and the enclosure  52  is coupled to an air suction or vacuum line  54  so as to enable air movement, as indicated by the arrows  56  in  FIG. 5 , to lift the product upwardly to release from the molds.  
         [0039]     Alternatively, the unloading station  24 , where the formed and cooked products  18 ′ are dismounted from the form surfaces  19  of the mold bodies  20 , is equipped with means  61  to insure the transition of the cooked products  18 ′ onto a take away conveyor  62  as shown in  FIGS. 6-12 . Although the formed and cooked products  18 ′ may readily dislodge passively as by gravity from the form surfaces  19  as the mold bodies  20  traverse the discharge end sprocket  26  of the conveyor  21 , positive dismounting means may be provided to prevent any products from sticking to the mold bodies and failing to dislodge unto the conveyor  62 . In one embodiment the mold bodies  20  are split into mold halves along their longitudinal center lines,  FIGS. 7 and 8 . At the interval when the conveyor carries the molds over the conveyor sprocket  26  the split mold sections are caused to shift from the closed condition shown in  FIG. 7  to an open or expanded condition as shown in  FIG. 8 , thereby dislodging the product  18 ′ from the mold body as shown in  FIG. 6 . An inclined, convex guide chute or a guide rod  63  is mounted as shown in  FIG. 6  so as to receive the formed product and guide it downwardly unto the take away conveyor  62 . As shown in  FIG. 8 , a centrally disposed cam member or guide rails  64  arranged at the base of the convex split mold body serves to urge the body halves to shift into the open condition for product dismounting.  
         [0040]     Referring now to  FIGS. 16-18 , split molds  20  are configured in the medial section for penetration by a fixed, finger like element  65  that serves positively to dislodge the product  18 ′ from the mold surface  19  as the molds are carried around the sprocket at the discharge station.  
         [0041]     Referring now to  FIG. 9 , in another embodiment of the means  61  assisting removal of the product from the molds, a curvilinear guide panel  66  having an end guide  67  is positioned outwardly of the mold bodies  20  in the 1 o&#39;clock to 5 o&#39;clock travel segment of the mold bodies on the conveyor sprocket  26 . In operation the formed products  18 ′ fall gravitationally from the mold bodies  20 , slide a distance along the guide panel  66  and are intercepted and controlled so as to maintain alignment by the end guide  67  before dropping a short distance onto the conveyor  62 . This arrangement encourages a smooth transition of the formed products  18 ′ from the conveyor  21  to the conveyor  62  in a manner that minimizes product crumbling, cracking, breakage and misalignment. Then the cooked and formed products  18 ′ are moved on the conveyor  62  to the packaging stage  16  or for other treatment.  
         [0042]     Referring now to  FIG. 10 , still another embodiment of the discharge means  61  is provided and comprises an endless conveyor  67  having a smooth, soft surfaced belt  68 . The conveyor is mounted at the product unloading station  24  in a manner such that the conveyor belt  68  that engages and wraps outwardly of the formed products  18 ′ on the mold bodies  20  over a distance covering an angle of about 120 degrees of arc of the sprocket thus maintaining the products on the form surfaces until they separate gravitationally and fall a short distance onto the conveyor  62 . The cooked and formed products are then moved towards the packaging or other end processing stage  16 .  
         [0043]     Referring now to  FIGS. 11 and 12 , yet another embodiment of the discharge means is shown and includes a slide box  68 . Flexible wipers  69  are provided as shown in  FIG. 12  on the lower portions of the slide box  68  and positioned to encourage the formed products  18 ′ to dislodge from the mold surfaces  20 , as indicated in  FIG. 11 . The products then slide downwardly onto the take away conveyor  62  to be transported to the packaging stage  16  or other end processing steps.  
         [0044]     For certain products after cooking and forming the removal of surface cooking oil can be desirable. This may be accomplished by the application to the products of a sweep of air or nitrogen and in certain cases steam. The apparatus for achieving this step is well known in the field and will not be duplicated here.  
         [0045]     While there has been disclosed above and illustrated in the several drawings what is considered to be the preferred embodiments of the present invention so as to teach those skilled in the art the principles of the applicants&#39; developments, the true scope of the inventions shall not be limited except as set out in the claims below.
Sheeted or relatively thin uncooked food products are arrayed for reception upon a procession of curved molds being conveyed along a process path. Once received on the molds and moving therewith, the products are deluged from above with curtains of hot cooking oil and thereby take the shape of the molds while cooking. The food products are dismounted from the molds at the end of the process path and are moved to a subsequent treatment station.