Abstract:
Apparatus for applying glaze to warmed doughnuts includes a base, an oven supported on the base, a food finishing area located below the oven, and a discharge area at an output of the food finishing area. A drive mechanism includes first couplings positioned in the food finishing area and discharge area. Supports, fixed to the base, project outward adjacent to each of the drive mechanism first couplings. Two conveyor units are included, each conveyor unit including a chassis and a driving component having a second coupling and supporting belt. Each conveyor unit chassis is mounted on the supports so that the second coupling engages one of the first couplings to provide power from the drive mechanism to the conveyor units&#39; driving components. The conveyors are releasable as a unit from the supports to facilitate cleaning of the apparatus.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates generally to machines for applying a glazing, icing or other similar coating to doughnuts, pastries and other comestible articles. The present invention is particularly directed to machines for applying such coatings to fully cooked and pre-frozen doughnuts that have been thawed, heated and glazed shortly or immediately prior to sale to achieve a “fresh” quality.  
           [0002]    Doughnuts, while traditionally a morning food to be consumed in conjunction with beverages such as tea or coffee, have become a popular snack item that can be consumed at virtually any time of the day. Many shops and fast service outlets are devoted solely to the manufacture and sale of fresh doughnuts. Other commercial establishments, such as full service grocery stores, smaller convenience stores, fast service and limited menu restaurants, gas stations and even bookstores, have attempted to satisfy the public demand for such food items. The manufacture of fresh doughnuts requires a significant investment in specialized machinery and considerable knowledge and skill unlikely to be possessed by most workers at these other commercial establishments. Further more, the specialized machinery and equipment requires daily cleaning that requires significant non-productive time by personnel. To avoid the substantial investment in equipment and personnel, these other commercial establishments have generally resorted to the sale of doughnuts and pastries that are prepared off-site.  
           [0003]    Doughnuts and pastries have a rather short shelf life due principally to the escape of moisture from the cooked article. Applying a glazing, icing or other similar coating over the entire exterior of the article not only enhances the taste, but also seals in a desirable level of moisture that can modestly extend its shelf life. Refrigeration of the finished doughnuts can further extend the shelf life, but almost immediately eliminates the hot, fresh quality desired by consumers. Thus, even well cared for goods often do not match the appeal of the fresh products produced on site at dedicated shops and outlets. There is also the additional problem for conventional off-site production of quickly responding the changes in consumer demand, often on a day-to-day basis. Any unsold products must generally be discarded when the shelf life is exceeded, which can substantially negatively impact the overall profit to be earned from the product.  
           [0004]    One alternative that has been employed with modest success in the use of bakery products, particularly raised doughnuts that are cooked and frozen at a central manufacturing facility. The frozen bakery products are delivered to commercial retail establishments in a frozen condition where they can be stored for considerable period before use. The products are typically quickly thawed and heated rapidly to recapture the fresh quality that the consumer desires, and then finished by the addition of a glaze or icing. The batches can be sized to meet the variations in consumer demand on a daily or even hourly basis. While existing apparatus allows retailers to quickly and continually produce desired quantities of “fresh” doughnuts through the day, the application of glazing and icing to the products presents an especially messy problem that still generally requires a measure of skill on the part of the worker, requires considerable cleaning time and effort, and is often very wasteful of the glazing or icing  
           [0005]    Thus what is needed is a machine that is simple to use and easy to clean to apply the desired amount of glaze, icing, or other finishing fluid onto previously heated doughnuts, pastries or other food products with little waste. It is preferable for the machine to be largely automated so that the entire operation can be operated by one person. It is also desirable that the machine occupy as little floor space as possible, and be reasonably priced so that the cost can be recovered within a reasonable time from the enhanced profits derived from the food products produced by the machine.  
           [0006]    Additionally, it is important that the machine be safe to operate, and provided with very simple and clearly marked controls so that the machine is operable by lower level employees. Finally, it is important that the food products produced by the machine have excellent flavor, freshness, and other characteristics likely to enhance customer appeal.  
         SUMMARY OF THE INVENTION  
         [0007]    A machine according to the present invention includes a floor-supported base that can include wheels to permit the apparatus to be easily moved from place to place to permit cleaning, servicing, and the like. The apparatus mounted on the base includes an oven that is generally intended for reheating previously cooked food products but can also be an oven for cooking or completing the cooking process of the food product in question. The oven generally includes a heater mechanism with associated temperature controls. The oven also includes a conveyor for conveying food products through the oven from an intake to an output. A food finishing area is located below the oven where the food products heated in the oven are finished with glaze, icing or the like. A chute is provided that directs the heated food products from the oven output to the food finishing area. A discharge area is located at an output of the food finishing area for receiving food products subsequent to their finishing.  
           [0008]    A drive mechanism is connected to the base and includes first couplings positioned in the food finishing area and discharge area. Supports, preferably in the form of rods, are also fixed to the base so that they project outward adjacent to each of the drive mechanism first couplings. Two conveyor units are provided, one being located in the food finishing area and one in the discharge area. Each conveyor unit includes a chassis, a driving component having a second coupling, and a porous belt supported on the chassis and driven by the driving component. Each conveyor unit chassis is mounted on the supports so that the second coupling on the driving component engages one of the first couplings of the drive mechanism to provide power from the drive mechanism to the conveyor units&#39; driving components. Each of the conveyor units is individually releasable as a unit from the supports to facilitate cleaning of the conveyor units.  
           [0009]    The conveyor unit in the finishing area receives the heated food products from the chute connected to the oven output and transports the food products through the finishing area. A drawer unit containing a heated water bath is provided below the finishing area. The water bath is intended to receive commercial containers of pre-prepared finishing such as glaze, icing or the like, which is heated by the water bath to a temperature that will facilitate the distribution of the icing or glaze in a fluid state over the food products as they pass through the finishing area. A pump, preferably a peristaltic pump, is provided that has an inlet, which can be submerged in the container of pre-prepared finishing fluid, and has an outlet connected to a distributor located above the conveyor in the finishing area. Finishing fluid, transported by the pump from the commercial supply container to the distributor, falls from the distributor in a predetermined pattern over the heated food products as they are transported through the finishing area by the conveyor unit.  
           [0010]    Any excess finishing fluid falls through the porous belt and is directed by a guide positioned below the finishing area conveyor unit back into the supply container. The guide situated below the finishing area conveyor unit can also including a slide forming a portion of the chute that introduces food products onto the finishing area conveyor unit. An air knife can be provided above the finishing area conveyor unit, directly down stream from the distributor, for removing excess finishing fluid from the food products passing through the finishing area. The air knife also initiates a cooling of the glaze, icing or other food finish that traps the desired amount of moisture in the food for maintaining its fresh quality for some period of time. The cooling continues as the food products are transferred to the conveyor unit located in the discharge area. By the time the food products have substantially completed the transport through the discharge area, the finish provided by the glaze or icing is sufficiently set so that the food products can be manipulated by hand onto display racks or trays, or placed in packages ready for the consumer to purchase.  
           [0011]    In a preferred embodiment, the conveyor chassis of the two conveyor units in the finishing area and the discharge area includes a pair of parallel side plates. The side plates are secured to each other in parallel relation by a pair of tubular elements having open ends forming channels. The tubular channels are of sufficient size to slidably receive the support rods that project outward from the base adjacent to one of the drive mechanism&#39;s first couplings. The distal end of the support rods supporting each of the conveyor units are preferably tapered, and at least one of the support rods includes an engagement element preferably taking the form of a groove adjacent to the distal end. Each of the conveyor units includes a second engagement element for cooperatively engaging the first engagement element to retain the conveyor unit chassis on the supporting rods. The second engagement element preferably takes the form of a latch engagable in the groove, the latch including a handle to permit manual disengagement of the latch from the groove. The latch preferably also includes a stop permitting the latch to only come in tangential contact with the support rod tapered end portion.  
           [0012]    Each of the first couplings on the drive mechanism preferably takes the form of a stepped surface or key. The driving component included in each conveyor unit preferably takes the form of a shaft that is coupled to the side plates by suitable journals. A stepped surface is provided on the end of the shaft forming the driving component that can engage the stepped surface on the drive mechanism when the conveyor unit is fully situated on the support rods. A plurality of toothed sprockets are fixed to the shaft forming the driving component that engage in the porous belt for driving said belt. The porous belt preferably takes the form of an open mesh wire belt engaged on the toothed sprockets of the driving component. One or more additional idler shafts can be provided as a part of each conveyor unit to further support the porous belt for movement relative to the conveyor unit chassis.  
           [0013]    The conveyor units of the present invention are preferably sized to be easily handled by one person, and can be quickly removed from the machine as a unit to be cleaned in any commercial sink. Any overflow of the glaze, icing or other finishing fluid is continuously returned to the commercial container in which it was initially supplied. At the completion of operation, the unused glaze or icing can be recovered by simply placing the original lid on the commercial container in which it was supplied. The container can be removed from the water bath to suitable storage for subsequent use. The hot water in the water bath can be used to flush through the pump and related tubing to quickly clean the finishing fluid distribution system. Other elements of the machine are similarly designed with ease of cleaning in mind so that clean-up of the machine at the end of the day can be accomplished in a short time, typically in a half-hour or less.  
           [0014]    Additional features of a machine of the present invention will become apparent to those skilled in the art from a consideration of the following description of a preferred embodiment. Throughout this description and including the claims it should be understood that the use of the term “first” with reference to any structure is not to be taken as requiring the presence of a “second” of that same or similar structure. Throughout this description and including the claims it should also be understood that the use of a term referencing a structure in the singular does not preclude the repeated or plural presence of that structure, and vice-verse. The following description should be considered in relation to the included drawings that are intended to depict the best mode of carrying out the invention as presently conceived.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a front elevation view of a doughnut glazing machine incorporating features of the present invention.  
         [0016]    [0016]FIG. 2 is an elevation view of the left side of the doughnut glazing machine shown in FIG. 1 partially broken away to show the glazing container within the water bath.  
         [0017]    [0017]FIG. 3 is an elevation view of the right side of the doughnut glazing machine shown in FIG. 1 with the water bath partly extended.  
         [0018]    [0018]FIG. 4 is a side elevation view similar to FIG. 2 but with the two conveyor units and chute removed to show the support rods and glaze distributor.  
         [0019]    [0019]FIG. 5 is a top plan view of one of the conveyor units partially broken away.  
         [0020]    [0020]FIG. 6 is an elevation view of a portion of one of the conveyor units showing the latch mechanism for engaging one of the supports.  
         [0021]    [0021]FIG. 7 is an elevation view similar to FIG. 4, the support rod being shown partially in section to show the engagement with the latch.  
         [0022]    [0022]FIG. 8 is an elevation view of a portion of one of the conveyor units from a side opposite that shown in FIGS. 6 and 7 showing the driving component engagement mechanism.  
         [0023]    [0023]FIG. 9 is an elevation detail view of the peristaltic pump used in the preferred embodiment of the present invention. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0024]    A doughnut glazing machine  10  according to the present invention is shown in FIGS.  1 - 4  to include a floor-supported frame  12  including a base  14  that can have wheels to permit the apparatus to be easily moved from place to place, to permit cleaning, servicing, and the like. The apparatus mounted on the frame  12  includes an oven  16 , that is generally intended for reheating previously cooked food products but can also be used for cooking or completing the cooking process of the food products. The oven  16  generally includes a heater mechanism with associated temperature controls. The oven  16  also includes a conveyor for conveying food products through the oven from an intake  18  to an output  20 . While the oven can include controls for controlling the oven temperature and rate of travel of food products through the oven, the controls are preferably not accessible to the casual operator of the machine  10 . Any adjustment of the oven temperature and conveyor speed is preferably preset by the factory and adjustable only by suitably trained service personnel. An intake rack  22  protrudes from the intake  18  sufficiently far to permit the manual introduction of food products, such as doughnuts, into the oven  16 . A downwardly inclined slide  24  projects from the output  20  and directs the food products exiting the output  20  of the oven  16  downward toward a chute  26  leading to a food finishing area  28  located below the oven  16 .  
         [0025]    The food finishing area  28  is where the food products that are heated in the oven  16  are finished with a glaze, icing or the like. The food finishing area includes a plurality of horizontal rods  30  that project outward from the frame  12  as shown in FIG. 4. A finishing area conveyor unit  32  is supported on a first pair of the rods  30 , which preferably have rounded or dome shaped outer ends  29 . A funnel-shaped guide  34  us supported on a second pair of the rods  31  below the finishing area conveyor unit  32 . A chute support  33  can be coupled to and supported by the guide  34  so that the chute  26  can direct the heated food products from the oven output  20  to the finishing area conveyor unit  32 .  
         [0026]    A distributor  36  is positioned above the finishing area conveyor unit  32  for distributing the glaze or icing onto any food carried by the conveyor unit  32 . The distributor  36  can take a variety of forms. In a preferred form, the distributor  36  comprises a tray  38  having a series of holes  40 , as shown in FIG. 4, suspended over an inclined plate  42 . The combination of the holes  40  and the inclined plate  42  tend to form a downwardly flowing curtain of fluid glaze or icing, when the glaze or icing is heated to the have the necessary fluidity. The finishing area conveyor unit  32  includes a porous belt  35 , as shown in FIGS. 2 and 5, so that the downward flowing curtain of fluid glaze can pass through the finishing area conveyor unit  32  and into the funnel shaped guide  34 . The finishing area also include an air knife  44 , including a source  45  of filtered air, suspended above the finishing area conveyor unit  32  to generate a downward flow of air that tends to remove any excess glaze or icing from any food product passing below the air knife  44 . The downward flow of air from the air knife  44  has the additional benefit of initiating a cooling of the glaze so that the food products can, subsequently, be more easily handled by the machine operator.  
         [0027]    A supply area  46  is located below the food finishing area  28 . The supply area  46  includes a water bath  48  including a heater  47  that is preferably situated in a drawer assembly  50 , which is movable relative to the frame  12  on drawer slides  15 . The water bath  48  is intended to receive commercial containers  49  of pre-prepared finishing such as glaze, icing or the like as shown in FIG. 2. The contents of the commercial container  49  is heated by the water bath  48  to a temperature that will facilitate the distribution of the icing or glaze in a fluid state over the food products as they pass through the finishing area  28 . A pump  51 , preferably taking the form of a peristaltic pump and motor  53  supported on stand  55 , is provided that has an inlet tube  52 , which can be submerged in the container of pre-prepared finishing fluid  49 . The pump  51  also has an outlet tube  54  connected to the distributor  36  located above the finishing area conveyor unit  32 . Finishing fluid, when sufficiently heated by the water bath  48 , is transported by the pump  51  from the commercial supply container  49  to the distributor  36 , falls from the distributor  36  in a curtain or other predetermined pattern over the heated food products as they are transported through the finishing area  28  by the conveyor unit  32 . Any excess finishing fluid falls through the porous belt  35  of the finishing area conveyor unit  32  and is directed by guide  34  back into the supply container  49  that is situated in the water bath  48 . Thus, during a coating operation, the flow of finishing fluid is continuously repeated and a substantial number of doughnuts or other pastries can be coated without stopping the machine either for re-supply or cleaning.  
         [0028]    A discharge area  56  is located adjacent to the food finishing area  28  for receiving food products subsequent to the addition of glaze, icing, etc. The discharge area  56  includes a conveyor unit  58  that is situated immediately adjacent to the finishing area conveyor unit  32  so that the food products are automatically transferred from conveyor unit  32  to conveyor unit  58 . A tray  60  is preferably provided below the discharge area conveyor unit  58  to prevent any glaze or icing from falling onto the floor. The length of the conveyor unit  58 , and its operating speed are selected so that by the time the food products have substantially completed the transport through the discharge area  56 , the finish provided by the glaze or icing is set and the food products can be manipulated by hand onto display racks or trays, or placed in packages ready for the consumer to purchase. While additional racks and trays can be added to the discharge area, it will be appreciate that it is generally desired to contain the apparatus to as small an area as possible to permit its accommodation is smaller retail outlets such as convenience stores, and the like.  
         [0029]    The oven  16 , conveyors  32  and  58 , heater  47 , pump  51  and air source  45  are supplied power through a common control panel  62  that is fixed to the frame  12  in a convenient position facing the machine operator. The control panel  62  includes a number of switches  64  for controlling the supply of power to the various elements of the machine  10 . Electrical power is preferably supplied to the machine  10  through a single power cable, and is distributed from the control panel to the various elements by electrical cables running through a common chase  66  that is connected to a motor housing  68 . Motors  70  for operating the conveyors  32  and  58  are situated within the motor housing  68 . A first coupling  71 , preferably in the form of a stepped surface or key, is connected to each motor  70  that projects through motor housing  68  into the food finishing area  28  and discharge area  56 .  
         [0030]    An important feature of a machine  10  of the present invention is its facility for ease of cleaning. An important feature that contributes to this facility is the use of conveyor units  32  and  58  that are conveniently handled as a single assembly. A representative conveyor unit  32 ,  58  is shown in greater detail in FIG. 5 to include a chassis  59  having pair of longitudinal panels  72 , including outwardly extending ledges  73 , situated at the lateral edges of the conveyor unit. The two ends  74  and  76  of at least two tubing elements  78  are coupled to the longitudinal panels  72  so that the panels are situated at a prescribed distance from each other. Shafts  80  and  82  are coupled to the panels  72  by suitable journals  84  to that the shafts  80  and  82  can rotate with respect to the longitudinal panels  72 . Sprockets  86  are fixed to the shafts  80  and  82 , the sprockets  86  including teeth  88  that engage the porous belt  35 , which is preferably made of stainless steel wire. One or more additional idler shafts, and additional sprockets, can be provided as a part of each conveyor unit  32 ,  58  to further support the porous belt  35  for movement relative to the conveyor unit chassis  59 . Any rotation of either shaft  80  or  82  causes the porous belt  35  to move with respect to the chassis  59 , which in turn also causes the other shaft  82  or  80  to rotate. At least one of the shafts  80  or  82  includes a coupling feature, such as the coupling slot  81  shown in FIG. 8 which is adapted to be coupled to a corresponding coupling element  71  on a projecting shaft from one of the drive motors  70 . The coupling slot  81  engages the stepped surface on the drive mechanism  71  only when the conveyor unit  32 ,  58  is fully situated on the support rods  30 .  
         [0031]    The tubing elements  78  include open ends and are of sufficient size to be slidably received over the support rods  30 . This arrangement of cooperatively engaging support rods  30  and tubing elements  78  permits the conveyor units  32  and  58  to be easily and quickly installed on and removed from the machine  10  as a whole unit. The disassembly of the conveyor units is not necessary to permit the units to be completely cleaned after each glazing operation. The retention of the conveyor units  32  and  58  on the support rods  30  is facilitated by the use of a latch  90  shown in FIGS.  5 - 7  and located on the opposite side from the coupling slot  81 . The latch  90  includes a pivot member  92  supported on one of the panels  72  of the conveyor unit. An arm  94  projects outwardly from the pivot member  92  and includes a downwardly extending end portion  96  adapted to contact ledge  73  of longitudinal panel  72  and thus form a stop so that the arm  94  cannot block the opening  77  into the interior of the tubing element  78 . As the conveyor unit tubing elements  78  are slipped over the outwardly projecting support rods  30 , the domed end portion  29  of the support rod contacts and displaces the arm  94  so that a lower surface  95  of the arm rests on the top of support rod  30 , as shown in FIG. 6. A slot  98  is provided in the upper surface of at least one of the support rods  30 , the slot  98  being of sufficient width to receive the lower surface  95  of arm  94  to retain the conveyor units on the support rods  30 . The latch  90  also includes a handle  100  that permits the latch to be quickly and easily disengaged from the slot  98  to permit removal of the conveyor as a unit from the machine  10 . Once removed from the machine  10 , the conveyor assembly can be easily washed in a commercial sink, or commercial dishwasher without further disassembly.  
         [0032]    Another important feature that contributes to the ease of cleaning of the machine  10  is the use of a peristaltic pump  51  and motor  53  supported on stand  55 . The peristaltic pump  51  has an inlet coupling  102  for engaging the inlet tube  52  that has a distal end that can be submerged in the container of pre-prepared finishing fluid  49 . As shown in FIG. 9, the peristaltic pump  51  also has an outlet coupling  104  for engaging the outlet tube  54  connected to the distributor  36  located above the finishing area conveyor unit  32 . A segment of elastic, flexible tubing  106  is coupled between the inlet coupling  102  and outlet coupling  104  and surrounds a pair of rollers  108  coupled to the ends of pivot arm  110 . The pivot arm  110  is rotated about an axis  112  by motor  53  in the direction R. The rotation of the pivot arm  110  causes a repeated squeezing action on the flexible tubing  106 , which propels the finishing fluid from the container  49  to the distributor  36 . While FIG. 9 shows only a single segment of flexible tubing  106 , it will be apparent to those skilled in the art that more than one such tubing segment  106  can be employed with more than one set of rollers  108  to achieve the desired volume of flow of finishing fluid. In this way, the finishing fluid is wholly contained within tubing  52 ,  106 , and  54  during its transport from the container  49  to the distributor  36 .  
         [0033]    At the completion of a glazing operation, the distal end of inlet tubing  52  is removed from the container  49  of pre-prepared finishing fluid. After any excess glaze is allowed to drain from the distributor  36  and the funnel shaped guide  34  back into the container  49 , the container  49  is removed from the water bath  48  and stored for use in a subsequent glazing operation. A suitable surfactant such as a commercial soap or a detergent can then be added to the water bath  48 , which is generally still hot. The distal end of the inlet tubing  52  can then be inserted into the water bath and the pump  51  can be supplied with power so that the still hot water and surfactant flows upward through the tubing  52 ,  106 , and  54 , and downward through the distributor  36  and guide  34 , thus substantially cleaning the main flow path for the glaze or other finishing fluid. Clean rinse water can be substituted for the initial water-surfactant mixture as required until the system is cleared of all glaze. The tubing  52  and  54  can then be uncoupled from the pump  51 , and the flexible tubing  106  removed from the pump to remove any moisture from the tubing so that it is ready for the next glazing operation. The remainder of the machine  10  is easily wiped down to meet the necessary food handling cleanliness standards required of food machinery. Since the glaze is pumped upward completely within the tubing  52 ,  106  and  54 , there is no emersion of a pumping mechanism or a food product transport mechanism into the glaze or other food finishing liquid. As a result, the clean up of the machine  10  can be accomplished within an acceptably short period of time, typically in a half-hour or less.  
         [0034]    While the present invention has been described with reference to the illustrated preferred embodiment, it will be appreciated by those skilled in the art that other embodiments can be constructed that fall within the spirit of the present invention as claimed in the following claims.