Many restaurants' success depends on how quickly customers can be served with food items that a customer orders. If the rate at which a restaurant cooks food products equals the rate at which those same food products are being ordered and sold, a fast food restaurant can theoretically have freshly-cooked foods ready to serve for customers as they arrive. Since it is not always possible to match cooked-food production with customer ordering rates, and since fast food restaurant customers expect to receive their ordered food items quickly, many fast food restaurants pre-cook various food items and keep them warm, ready for sale until a customer arrives and purchases a pre-cooked food item.
Pre-cooked food items cannot be stored for prolonged periods and must be kept warm while they are being held. Prolonged heating causes food texture and flavor to deteriorate. The time that a food product can be kept warm yet remain palatable will vary with each type of food product. It is therefore beneficial to have an ability to store different types of foods at different temperatures and keep track of the time that a food has been kept warm.
Food holding cabinets are well known in the prior art. A problem with prior art food holding cabinets, as with most commercial restaurant equipment is that they sometimes fail and require a service technician to repair. In keeping with food service operators' goal of reducing cost, it would be desirable to provide on-site service ability to a food holding cabinet whereby repairs can be effectuated by a restaurant operator, on-site and without having to call a service technician.
Preferred embodiments are set forth in the following detailed description and accompanying drawings in which like reference numerals represent like parts.
As can be seen in
The front face 22 and the rear face 24, are provided with snap-into-place bezels, which are also referred to herein as snap-in escutcheons or simply escutcheons, identified in the figures by reference numeral 26. As described more fully below, the escutcheons 26 cover the edges 25 of the shelves 21. They also define openings into food storage compartments 23. And, the escutcheons 26 provide user interface devices, which include display devices and user-actuated control devices, the function and operation of which is described more fully below.
Importantly, the escutcheons 26 used on both the front and rear faces of the cabinet 10 and are interchangeable. The escutcheons 26 are thus configured to have electrically parallel electrical connectors 46 at each end of the escutcheon 26, which mate with chassis-located connectors 50 described more fully below but preferably located to one side of each cabinet face.
Below the electronics compartment 15 are several horizontal and substantially planar, thermally-conductive shelves 21. The shelves 21 are vertically separated from each other in the chassis 12 and fixed between the left side 18 and right side 20 to define food-holding compartments 23. The vertical separation distance between each shelf 21 defines the height of each compartment 23 and thus the maximum height of a food item or the packaging for a food item.
The shelves 21 and the compartments 23 are considered to extend horizontally across most of the width of the cabinet 10. The shelves 21 are preferably made from thermally conductive materials such as aluminum, copper or steel, so that the temperature of the food holding compartments 23 can be maintained by the transfer of heat from the shelf 21 into the compartment 23, or from the compartment 23 into the shelf 21. Different types of temperature control elements 51 are embedded into each shelf 21 or otherwise thermally coupled thereto. Compartment temperature can thus be achieved by controlling the temperature of the temperature control elements 51, which in turn controls the temperature of the thermally conductive shelves 21 defining the compartments 23 thus effectively determining compartment temperature.
In a preferred embodiment, the shelves 21 of the cabinet 10 are open between the sides 18 and 20 and the front face 22 and rear face 24 but are nevertheless considered to be horizontally subdivided into temperature-controlled zones. The different zones for each shelf are identified in
A temperature control element such as a heater 51 embedded in the shelf 21 and centered in the “A” zone is separately controlled from other temperature control elements or heaters 51 embedded in the same shelf 21 and centered in zones B and C. In an alternate embodiment, zones A, B and C and corresponding embedded heaters 51 are thermally isolated from each other using a thermal break, such as those disclosed in co-pending application Ser. No. 12/267,449 entitled, BIFURCATED HEATED TOASTER PLATEN, which is assigned to the assignee of this application. The content of the co-pending application Ser. No. 12/267,449 is incorporated herein by reference, at least with regard to heated platens and the thermal breaks disclosed therein. In yet another embodiment, the zones are isolated from each other by vertical dividing walls 72 that extend between the top and bottom of shelves 21 defining a compartment 23 between them.
In an alternate embodiment, the circuit board 52 includes a microprocessor and one or more external memory devices coupled to the microprocessor's address, data and control lines using well-known, conventional methods and devices. For reasons set out below, external memory devices coupled to a microprocessor are preferably embodied as EEPROM or equivalent, in order to enable the storage of new program instructions and/or data for the computer 54, as set forth more fully below.
In addition to the computer 54, the circuit board 52 includes either high power field effect transistors (FETs), silicon controlled rectifiers (SCRs), TRIACs or relays, or a mixture of such devices to effectuate the control of electric energy to heat transfer devices 51. Semiconductors as well as mechanical relays used to control electricity provided to the heat transfer elements 51, are collectively referred to herein as current-controlling semiconductor devices and identified in the figures by reference numeral 59, even though relays are generally considered to be mechanical devices.
The current-controlling semiconductors 59 (current control devices 59) are electrically coupled between an external power source 80 (See
In addition to current control devices 59, the circuit board 52 includes other interface circuitry 57 to interface (electrically couple) the computer 54 to the aforementioned user interfaces in the escutcheons 26 as described above and in the aforementioned co-pending application. Such circuits 57 also include electrostatic discharge (ESD) suppression devices to enable the circuit boards 52 to be inserted into and removed from the cabinet without having to power the cabinet down. Stated another way, ESD suppressors imbue the ability to “hot swap” the circuit boards 52.
Circuits and devices that interface a computer to an LED, LCD display, electronic paper, bulbs, switches, temperature sensors and keyboards are well known in the art. Such devices are too numerous to name but include devices such as analog-to-digital (A/D) converters, digital-to-analog converters, display drivers and the like. There are many devices that couple a computer to a peripheral device and a description of them is omitted for brevity. Regardless of how signals from peripherals to the computer 54 are coupled to it, analog and digital, information-bearing signals exchanged between devices in the cabinet, e.g., user interfaces in the cabinet 10 and in the escutcheons, sensors, and the computer 54, determine how the computer's program instructions, when executed, effectuate temperature control of a compartment 23.
The current-controlling semiconductor devices 56 receive control signals from the computer 54 such that signals from the computer 54 modulate or switch the current to the temperature control devices 50 in the cabinet. The control signals that the computer 54 send to the semiconductor devices 56 are determined by the computer's executable program instructions as well as data (non-executable) stored in memory and, in some instances, signals the computer 54 receives from devices in the cabinet 10, including temperature sensors 82 (See
In
The motherboard 60 is elongated and provided with multiple sets of connectors 62 to enable multiple circuit boards 52 to be connected to it. Conductors inside ribbon cable 76 and other wires not shown in
Devices external to the circuit board 52 include temperature control elements 51, user interface devices in the escutcheons, temperature sensors and a master controller 70 in the electronics compartment 15. Alternate and equivalent embodiments of the circuit board 52 use, one, two or more connectors, not shown in the figure. Still other embodiments use circuit board edge connectors, well known to those of ordinary skill in the electronics and computer arts. For purposes of simplicity and brevity, connectors of any kind that enable the electrical connection of devices on the circuit board 52, to devices external to the circuit board 52 are collectively referred to herein interchangeably as either a connector or an edge connector.
As shown in
The brackets 66 are separated from the sidewall 18 of the cabinet 10 by a small distance such that the height of electronic components on the circuit board 52 and/or a connector 58, will not clear the sidewall 18 if the circuit board 52 is inserted into the brackets with the component side of the circuit board facing the cabinet sidewall 18. The location of the brackets on the mother board 60 relative to the cabinet sidewall 18 thus prevents the circuit board 52 from being inadvertently inserted upside down, i.e. in an improper orientation. The brackets 62, in combination with the cabinet sidewall 18 effectively form a card cage 64 that prevents the circuit boards 52 from being installed incorrectly into the motherboard 60. The brackets 66 and cabinet sidewall also make the circuit boards 52 “self-aligning” with respect to the connectors 62 on the motherboard 60.
The concept of a bus carrying digital signals between a computer and devices peripheral to the computer, is well known to those of ordinary skill in the computer and electronic arts. Since the functionality of the bus is effectuated by the ribbon cables (and equivalents thereof), for purposes of simplicity, the terms “bus” and “ribbon cable” are thus used interchangeably hereinafter. For purposes of clarity, both of them are identified by reference numeral 76.
The computer 54 on the circuit board 52 is responsive to commands it receives from the master controller 70 over the bus 76. It is also responsive to information and inputs it receives from devices peripheral to it, such as escutcheon-located user interface devices and one or more temperature sensors, not shown. In a preferred embodiment, the computers 54 on the control boards 52 are thus considered to be “slaved” to the master controller 70.
As shown in
Each computer 54 on each circuit board 52 is coupled to the bus 76 such that each computer 54 “sees” all of the “information” on the bus 76. The master controller 70 selectively communicates with a particular slave computer 54 using an address that each slave computer 54 obtains from the mother board 60 (or a connector 62). The address obtained from the mother board 60 corresponds to a shelf or shelves that a circuit board 52 will control.
In a preferred embodiment, the communications between computers is via a serial communications protocol reminiscent of Ethernet. Messages from a sender are broadcast on the bus. Broadcast messages are received and selectively acted upon by the recipient to which a message was addressed.
Packets sent over the bus include a field that identifies the source of a packet by the logical address of the sender and a second field that identifies the recipient of the packet by its logical address. A packet payload contains all or part of a message being sent from the sender to the recipient. The addresses used by the master controller 70 and the slave computers 54 to communicate with each other are the addresses obtained from the mother board 60.
The address of a particular card cage and thus a computer 54 on a circuit board 52, is effectuated by electrically connecting various pins of the connector 62 to either Vcc or ground, which represent logic 1 and zero respectively. When the connectors 58 on the circuit board 52 engage the connectors 62 on the mother board 60, executable program instructions stored in memory for the computer 54, cause the computer 54 to “read” its logical address from the connectors 58/62. In an alternate and equivalent embodiment, signal leads on the mother board 60 apply voltages of Vcc or ground to pins of the connectors 62 installed into the mother board 60. In yet another embodiment, so-called DIP switches are used on the circuit boards 52 instead of connectors and configured “on” or “off” to provide a card cage address to the computer 54.
Conductors in the ribbon cable that comprises the bus are connected to various terminals or connection points on the motherboard 60. Conductive paths or “traces” on the motherboard, carry the signals on the ribbon cable, to different terminals of different connectors 62A, 62B and 62C.
In a preferred embodiment shown in the figure, a first pair of connectors 62A and 58A that connect to each other, convey signals between the controller 54 and the master controller 70. Three conductors are three address lines, which are identified by reference numeral 84. Two of the address lines 84 are shown as being “pulled-up” to Vcc. One address line 84 is “pulled down” to ground through a pull down resistor. The voltages on the three address lines 84 correspond to a binary-valued or digital address of “011” or “110” depending on which line is considered to be the least significant bit and/or most significant bit of a three-bit address space, i.e., addresses ranging from zero through seven inclusive.
When a control circuit board 52 is inserted into the card cage for shelf 1 and the connectors 58 & 62 engage, the controller 54 on the circuit board 52 can scan the address of the card cage/shelf to determine the address that it will use on the bus 76. The slave controller 54 thus determines which shelf it is responsible for controlling. Communications between that slave controller and the master controller 70 use the address obtained from the mother board.
Hard-wiring an address for a particular shelf of the cabinet enables software in the controller 54 to determine where it is installed and how it is to operate. It also allows control boards 52 to be generic, i.e., non-specialized.
Shelf 1 could be used to keep certain types of foods at a high temperature. A different shelf could be required to kept cold. Imbuing the control boards 52 with the ability to read their locations on the mother board enables the master controller 70 to flexibly control the cabinet 10 by controlling what the slave computers 54 are able and/or permitted to do.
In
The master controller 70 is depicted as being connected to an external memory device 83 via the bus 76. The master controller 70 includes software, which when executed by the controller 70, maintains the temperature of compartments 23 by controlling the slave computers 54, directing each of them as needed to keep all the compartments' temperatures relatively constant in order to keep a food item at a substantially constant temperature. The master controller 70 also maintains the time that a food item has been kept in a compartment, which is determined by a user's actuation of a switch or other input/output device on an escutcheon 26, the actuation of which is read initially by a slave computer 54 and then passed to the master controller 70 over the bus.
Time periods that a food item is kept in a compartment are compared against time limits for the food item. Such time limits can be user-specified through the front panel input/output (I/O) 85.
Those of ordinary skill in the art will recognize from the foregoing description that food items in a multi-compartment food holding cabinet can be kept at a constant temperature by appropriately controlling heat transfer elements such as electric heaters. In the apparatus described above, the method includes downloading to a first slave computer from a master computer, data or executable program instructions that control the slave computer's control over heat transfer devices. The data and/or instructions downloaded to one slave computer can optionally be different from the data and/or instructions downloaded to a second computer. The determination of which set of instructions to download to the power supplies 52 can be made using an operating parameter for a compartment 23 that the power supply is connected into via the motherboard 60.
Data downloaded to the slave computers can be data that specifies a holding temperature for the first compartment, a holding time limit for a food item, operational instructions, i.e., instructions to display to a user as to how to operate the cabinet, an elapsed time for a food item held in the first compartment and/or the identity of a food item in a first compartment.
Those of ordinary skill in the art will recognize that the master controller 70 is preferably a single chip microcontroller with its own on board RAM, ROM and EEPROM. The bus also couples the master controller 70 to the cabinets' front panel input/output-user interface devices described above. Finally, the master controller 70 is also coupled to various communications devices through which the master controller 70 can communicate with the outside world. The interfaces for external communications include a USB port 84, and 802.1x (wifi or wimax) wireless interface 86 as well as an Ethernet interface 88, removable storage device such as a CD or DVD drive, SIM cards or other removable storage media. The external communication interfaces 84, 86 and 88 enable the master controller 70 to receive executable program instructions and data for either the master controller 70 or the slave CPU 54.
In a preferred embodiment, memory onboard the master controller die, includes memory that stores executable program instructions for the slave computer 54 as well as data. In an alternate embodiment, the executable program for the slave computer 54 and data can also be stored in the external memory 83.
Storing the program executed by the slave computer 54 in the master controller provides several benefits. Firmware for the slave computer 54 can be kept up-to-date by acquiring new programs via one or more of the external communications interfaces. It also allows the firmware for the slave computer 54 to be changed based on customer requirements or food holding requirements.
In a first embodiment, the slave computer 54 on the circuit board 52 is pre-programmed with only a small program, which reads the address of the shelf wherein it is located from the mother board 60. Other instructions issue a request to the master controller 70 via the bus, asking the master controller 70 for a download of instructions that will give the slave controller 54 its “personality.” In yet another embodiment, the slave computer 54 is pre-programmed with enough code for it to notify the master controller of its presence on the bus and to thereafter wait for a download from the controller 70. In yet a third embodiment, all of the operating instructions are burned into the slave computer 54, however, operating parameters such as temperatures to maintain a compartment at, or food holding time limits are downloaded from the master controller 70 or received through one or more of the user interfaces. In yet another embodiment, the slave computer 54 is pre-programmed with sufficient instructions that enable it to take control of the bus 76 and download its operating program and/or data from the external memory under its own control. Once the program instructions are down loaded from the external memory, the slave computer 54 can thereafter operate autonomously, subject of course to the control instructions it receives from the master controller. Microprocessors that embody the master controller 70 and the slave computers 54 are different types of devices, however, alternate embodiments use the same microprocessor for both the master and slave functions.
In most implementations, a particular program is required to control heating elements for the shelves. A separate and different program is required to control Peltier devices that refrigerate and/or heat one or more compartments.
It should be noted that the download provided to the slave computer 54 includes software that reads and controls the user interfaces in the escutcheons for a particular shelf. Such software includes instructions and data to display information to an operator.
In yet another embodiment, the downloaded software includes diagnostics that can test devices on the circuit board 52 as well as the functionality of heat control elements 50, temperature sensors 82.
Master/slave communications over the bus 76 include: downloading commands to the slave computers 54 from the master controller; uploading commands/requests from the slave computers 54 to the master controller; downloading operating parameters, i.e., data to the slave computers from the master controller; uploading collected data from the slave computers 54 to the master controller; and, downloading executable program instructions from the master controller to one or more of the slave computers 54, which when loaded into a slave computer, change the operating characteristics or “personality” of a slave computer 54 into which the new program instructions are installed. The master controller 70 can either demand the slave computer 54 to accept a download or receive a request for a download from a slave computer 54.
In a preferred embodiment, the download is requested by the slave computer 24. In an alternate embodiment, the slave computers 54 are able to seize control of the bus 76 and autonomously download instructions and/or data from either the external memory 83 or from one or more of the external communications devices 92, 94, 96 and/or 98.
The foregoing description is for purposes of illustrations only. The true scope of the invention is set forth in the appurtenant claims.