Abstract:
A conveyor oven having an oven chamber with a single opening by which a food product enters and exits on a conveyor belt that is reversibly driven to convey the food product in and out of the oven chamber in a reciprocating manner. Also, the food is conveyed to a cooking position in an oscillating range within the oven chamber and then moved back and forth in the cooking range in an oscillatory manner within the oscillating range so as to prevent burning that would otherwise occur if left stationary.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/254,070 filed on Oct. 22, 2009, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     This invention relates to an oven for cooking food. In particular, the invention relates to a conveyor oven with a reversibly driven conveyor belt. 
     BACKGROUND OF THE DISCLOSURE 
     Conveyor ovens are known in which a conveyor belt is disposed between an inlet and an outlet. The conveyor belt is driven in a single direction from the inlet toward the outlet. Food is placed on the conveyor outside the inlet and conveyed into the oven for cooking and out of the oven via the outlet. Ovens of this type (known as pass-through conveyor ovens) require a rather large footprint inasmuch as the food entry and exit areas each require space. However, space is limited in many cooking kitchens. In addition, pass-through conveyor ovens have limited orientation possibilities. 
     There is a need for a conveyor oven with a reduced footprint. 
     There is also a need for a conveyor oven with flexible orientations. 
     SUMMARY OF THE DISCLOSURE 
     A conveyor oven of the present invention comprises an oven chamber with a single opening by which food enters and exits the oven. The conveyor is driven in a reciprocating manner to convey food via the single opening into the oven chamber and out of the oven chamber. In another embodiment, the food is moved to a cooking position in the oven chamber. The conveyor belt is then driven in an oscillating manner inwardly and outwardly about the cooking position. The oscillating motion of the food about the cooking position prevents burning that would otherwise occur if the food were maintained stationary at the cooking position. The conveyor oven of the present invention has a small footprint and can be oriented with the oven back toward a wall. 
     A conveyor oven of the present disclosure comprises an oven chamber having a single opening. A conveyor comprises a conveyor belt that extends through the single opening so as to be disposed partly inside and partly outside the oven chamber. A controller controls the conveyor belt to move in a reciprocating manner to convey a food product inwardly and outwardly of the oven chamber via the single opening. 
     In accordance with another embodiment of the conveyor oven of the present disclosure, a sensing device is located to detect a presence of the food product on the conveyor belt. 
     In accordance with another embodiment of the conveyor oven of the present disclosure, the controller controls the conveyor belt to move outwardly in a slow mode in an absence of the food product on the conveyor belt, and to move inwardly in a faster mode in a presence of the food product on the conveyor belt. 
     In accordance with another embodiment of the conveyor oven of the present disclosure, a thermal device is controlled by the controller to provide thermal energy to cook the food product. 
     In accordance with another embodiment of the conveyor oven of the present disclosure, the thermal device is selected from the group consisting of: electrical resistance device, gas burner device, microwave device, infrared device, and any combination thereof. 
     In accordance with another embodiment of the conveyor oven of the present disclosure, the controller further controls the conveyor belt to move the food product back and forth within an oscillating range located within the oven chamber so as to prevent burning of the food product. 
     In accordance with another embodiment of the conveyor oven of the present disclosure, the controller controls the conveyor belt to move the food product inwardly to a cooking position located within the oscillating range. 
     In accordance with another embodiment of the conveyor oven of the present disclosure, a thermal device is controlled by the controller to deliver thermal energy to the food product within the oscillating range. 
     In accordance with the present disclosure a method of controlling a conveyor oven comprises: 
     moving a conveyor belt in a reciprocating manner through a single opening of an oven chamber of the conveyor oven to move a food product on the conveyor belt inwardly and outwardly of the oven chamber; and 
     cooking the food product in the oven chamber. 
     In accordance with the present disclosure the method further comprises: moving the conveyor belt outwardly in a slow mode in an absence of the food product on the conveyor belt. 
     In accordance with the present disclosure the method further comprises: detecting a presence of the food product on the conveyor belt and then moving the conveyor belt inwardly in a faster mode. 
     In accordance with the present disclosure the method further comprises: further moving the conveyor belt to oscillate the food product back and forth within an oscillating range located within the oven chamber. 
     In accordance with the present disclosure the method further comprises: moving the conveyor belt to move the food product inwardly to a cooking position within the oscillating range. 
     In accordance with the present disclosure the method further comprises: delivering thermal energy to the food product within the oscillating range. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other and further objects, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference characters denote like elements of structure and: 
         FIG. 1  is a perspective view of a conveyor oven of the present invention; 
         FIG. 2  is a block diagram in part and a schematic diagram in part of the cooking system of the conveyor oven of  FIG. 1 ; 
         FIG. 3  is a block diagram of the controller of the cooking system of  FIG. 2 ; 
         FIG. 4  is a flow diagram of the conveyor program of the controller of  FIG. 3 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , a conveyor oven  20  of the present invention comprises a housing  22  that is secured to a base portion  36 . Housing  22  includes side walls  24  and  26 , a back wall  28 , a top wall  30 , a bottom wall  32  and a front wall  34 . An oven chamber  40  is disposed within housing  22  and is supported by housing  22  and/or base portion  36 . An opening  38  is disposed in front wall  34  and provides a point of entry and exit to and from oven chamber  40 . 
     Housing  22  and/or base portion  36  provide support for a conveyor assembly  42  that is disposed partly in oven chamber  40  and partly outside oven chamber  40 , extending through opening  38 . 
     A control panel  43  is situated on side wall  24 . In alternate embodiments, control panel  43  may be located in other places on housing  22 . For example, control panel  43  may be located on front wall  34 . Control panel  43  includes a display, a key entry pad, an ON/OFF switch and the like, none of which is shown on the drawing. 
     Referring to  FIG. 2 , conveyor assembly  42  is shown extending into oven chamber  40  via opening  38  of front wall  34 . Conveyor assembly  42  comprises a conveyor belt  46  disposed about a drive wheel  48  and an idle wheel  50 . An upper heating element  52  and a lower heating element  54  are disposed above and below conveyor belt  46 , respectively, in oven chamber  40 . 
     A stepper motor  56  is disposed in housing  22  and coupled as shown by dotted line  57  to a drive axle  47  of drive wheel  48 . A sensor or detector device  58  is positioned to sense or detect a food product placed on conveyor belt  46  outside oven chamber  40 . Generally, detector device  58  can be positioned at any suitable location that permits detection of food product interference. For example, the suitable locations include the top front, bottom front, either side of the front, middle front or other. Some detector devices may include multiple sensors. 
     Detector device  58  is preferably a proximity sensor, for example, model PRX+4400, available from Hermetic Switch, Inc. Alternative detector devices include a micro-switch, for example, model E47BM530, available from Eaton/Culver Hammer. Other alternate detector devices include a touch sensor including dielectric sensing as well as piezo-electric pressure sensing. For example, the touch sensor may be model T107-A4E-073, available from Piezo Systems. Another detector device that can be used is a sonar sensor, for example, model EFR-RTQB40KS, available from Panasonic. Another alternate detector device includes an optical transmitter that transmits an optical beam of either visible light or invisible light (for example, infrared) and an optical receiver disposed to the front of cooking apparatus  20 . A further alternate detector device includes a plurality of temperature sensors disposed at various locations in upper front outside oven chamber  40 . The temperature sensor output signals are provided to a controller  60  for processing to determine the presence of a food product on the conveyor outside oven chamber  40 . It will be apparent to those skilled in the art that detection circuitry may be provided to detect the presence of a food product based on the output signal(s) of the sensor(s). 
     Controller  60  is also located in housing  22 . Controller  60  is operative to control stepper motor  56  to drive wheel  48  in either the clockwise direction or the counterclockwise direction. When drive wheel  48  is driven in the clockwise direction, conveyor belt moves outwardly of oven chamber  40  as shown by arrow  62 . When drive wheel  48  is driven in the counterclockwise direction, conveyor belt moves inwardly of oven chamber  40  as shown by arrow  64 . 
     Controller  60  also controls turning heaters  52  and  54  on and off to control the cooking of the food product. Controller  60  also receives the output of detector device  58  indicating a food product placed on conveyor belt  46  outside oven chamber  40 . Controller  60  responds to the placement of a food product on conveyor belt  46  to operate stepper motor  56  so as to rotate drive wheel  48  in the counterclockwise direction and move conveyor belt  46  in the inward direction to a cooking position  66  located in-between upper heater  52  and lower heater  54 . During cooking of the food product, controller  60  is operative to oscillate the food product back and forth inwardly and outwardly about cooking position  66  in an oscillating range  68 . 
     Referring to  FIG. 3 , controller  60  comprises a processor  70 , an input/output (I/O) interface  72  and a memory  76  that are interconnected by a bus  74 . A cooking program  78  and a conveyor program  80  are stored in memory  76 . As shown in  FIGS. 2 and 3 , I/O interface  72  has connections  82 ,  84 ,  86 ,  88  and  90  to upper heater  52 , lower heater  54 , stepper motor  56 , sensor  58  and control panel  43 , respectively. Cooking program  78  comprises one or more cook procedures for cooking food products. These cook procedures may be downloaded from an external source (not shown) or entered manually from control panel  43  via connection  90 , I/O interface  72  and bus  74  to memory  76  under control of processor  70 . A user can also select from control panel  43  one of the cook procedures stored in memory  76  to cook a current food product. The external source, for example, may be a flash memory, a memory disk, a memory key, a remote server or other external source. 
     Conveyor program  80  includes a plurality of instructions, which when executed by processor  70  control the motion of conveyor belt  46 , upper heater  52  and lower heater  54  to move the food product into oven chamber  40  via opening  38 , to cook the food product and then return the food product via opening  38  to a location outside oven chamber  40 . 
     Referring to  FIG. 4 , conveyor program  80  begins at box  100  when the power is turned on for conveyor oven  20 . At box  102 , upper and lower heaters  52  and  54  are turned on. For example, the instructions may cause upper and lower heaters  52  and  54  to operate in an energy saving mode in which one of the heaters is turned off and the other heater is operated at a predetermined temperature below set temperature for cook procedures. For instance, upper heater  52  is turned off and lower heater  54  is operated to maintain the predetermined temperature below set temperature for cook procedures. 
     At box  104  the instructions cause processor  70  to control stepper motor  56  to move the conveyor belt slowly outward in a slow mode to prevent overheating of the conveyor. 
     At box  106  it is determined if a food has been placed on conveyor belt  46 . If not, the operations of boxes  104  and  106  are repeated until the output of sensor  58  changes (or a button is manually operated) to indicate placement of a food product on conveyor belt  46 . When this happens, the instruction(s) of box  108  cause conveyor belt  46  reverse its motion to move the food product inwardly to cooking position  66  inside oven chamber  40 . At this point the speed of conveyor belt  46  is increased to a faster speed in a fast mode. Cooking position  66  is programmable and, thus can vary from one cook procedure to the next. 
     At box  110  upper and lower heaters  52  and  54  are operated at set temperatures that are contained in the cook procedure currently being run. At box  112  conveyor belt  46  is oscillated inwardly and outwardly so that the food product moves back and forth about cooking position  66  in oscillating range  68 . Upper and lower heaters  52  and  54  are operated at the programmed temperatures of the cook procedure being run. 
     At box  114  when the cook procedure ends, conveyor belt  46  is operated at a faster speed to move the food product out of oven chamber  40 . At box  116  upper and lower heaters  52  and  54  are operated so as to be returned to the energy saving mode temperature. 
     At box  118  the speed of conveyor belt  46  is reduced to a slow speed in the slow mode and control passes to box  104  and execution of the instructions of boxes  104  to  118  are repeated. 
     The present disclosure having been thus described with particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the appended claims.