Abstract:
A method of manufacturing a service technician training apparatus for domestic appliance servicing comprises severing conductors within an actual appliance and connecting severed ends of the conductors to controllable switches. The training apparatus can include a plurality of the switches mounted on an instructor&#39;s console that is arranged to be obscured from view by the student that is troubleshooting the appliance.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to training apparatus for service personnel who repair domestic appliances. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is known to provide simulated appliances for training service personnel to troubleshoot malfunctioning appliances to determine the malfunction. 
         [0003]    U.S. Pat. No. 4,623,312 discloses a changeable modular electrical control training system to provide hands-on training in the servicing and troubleshooting of electrical control systems. The system comprises a plurality of structural electro-mechanical cubes that are removably attached to a structural power base or alternatively to an operating mechanical refrigeration training system (E.L.R.T.) Each of the cubes is adapted for combined mechanical and electrical connection to the power base or alternatively to another cube. 
         [0004]    The various cubes include simulators, controllers and source cubes to represent components of a field control system. Each of the cubes includes conventional electromechanical components which function similarly to the systems encountered in the field. Wiring inside the cubes establishes indicator light power circuitry and control system circuitry. 
         [0005]    The internal wiring in the cubes for control system circuitry is completed by the student using external patch cords to connect the cubes according to the instructor designed control circuit. Faults or failures are entered into the control system circuitry by the instructor, using instructor-controlled fault switches, to provide the student with troubleshooting problems that he or she must correct after establishing the location of these faults using conventional testing equipment. 
         [0006]    However, the cube system in U.S. Pat. No. 4,623,312 presents to the student a “representation” of a control system and not an actual control systems such as present on an actual furnace. The components analyzed by the students and the immediate environment of the components are not identical to what the student would encounter in the field. 
         [0007]    The present inventor has recognized that it would be desirable to provide a portable training system which would allow the students to troubleshoot an actual control system of a domestic appliance. 
         [0008]    The present inventor has recognized that it would be desirable to provide a training apparatus for a domestic appliance that replicated, to the greatest extent possible, the conditions that a field service technician would face in troubleshooting an actual malfunctioning domestic appliance. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention provides a training apparatus and a method of manufacturing a training apparatus. 
         [0010]    According to the preferred embodiment, a plurality of switches are provided on an instructor&#39;s console or back panel of the apparatus wherein an instructor can select in which circuit of the appliance to simulate a failure by opening the corresponding switch, the selection being hidden from observation by the student. The student must thereafter troubleshoot the appliance to determine the location and nature of the fault without knowing which switch or switches haves been selected by the instructor to simulate a fault or faults. 
         [0011]    The apparatus of the invention comprises an actual domestic appliance such as a furnace, air-conditioner, water heater, oven or refrigerator that is modified to have open circuits that are closable by a plurality of switches located on a back panel or instructor&#39;s console that is hidden from view of the student. The instructor is able to selectively simulate an open circuit in many of the appliance circuits, particularly those circuits that are prone to failure in the field. 
         [0012]    The method includes the steps of providing an actual domestic appliance and modifying the appliance by disconnecting circuits and reconnecting circuits via wires and switches such that the circuits can be selectively opened by an instructor to simulate failure of a circuit. The method can also include the step of adding a resistance to the circuit via the switch and a resistor to simulate a partial failure or a weakened component. The method can also include the step of closing a circuit to simulate a short circuit. 
         [0013]    Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a heating, ventilating and air conditioning unit (HVAC) embodiment of the present invention; 
           [0015]      FIG. 2  is a rear view of the HVAC embodiment of  FIG. 1 ; 
           [0016]      FIG. 3  is a fragmentary front view of the HVAC embodiment shown in  FIG. 1 ; 
           [0017]      FIG. 4  is an enlarged fragmentary front view of an instructor&#39;s console as shown in  FIG. 3 ; 
           [0018]      FIG. 5A  is a schematic diagram of furnace and ventilating units of the HVAC embodiment of  FIG. 1 ; 
           [0019]      FIG. 5B  is a schematic diagram of a condenser unit of the HVAC embodiment of  FIG. 1 ; 
           [0020]      FIG. 5C  is a portion of the schematic diagram of the furnace and ventilating units of  FIG. 5A ; 
           [0021]      FIG. 6  is a legend for the diagram of  FIG. 5A ; 
           [0022]      FIG. 7A  is a schematic diagram of a switch arrangement; 
           [0023]      FIG. 7B  is an alternate schematic diagram of a switch arrangement; 
           [0024]      FIG. 7C  is a further alternate schematic diagram of a switch arrangement; 
           [0025]      FIG. 8  is a schematic diagram of a water heater embodiment of the invention; 
           [0026]      FIG. 9  is a schematic diagram of an oven embodiment of the invention; and 
           [0027]      FIG. 10  is a schematic diagram of a refrigerator embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0028]    While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred features of the invention. It will be understood, however, that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific form of the combination of features that are illustrated and described. 
         [0029]      FIG. 1  illustrates a domestic appliance such as a central heating, ventilating and air-conditioning apparatus (HVAC)  20  of the present invention. The term “domestic” is meant to infer that the appliance would be of the type which could be found in a home or office. The apparatus  20  is substantially identical to a domestic HVAC apparatus such as would be found in a typical home. 
         [0030]      FIG. 2  illustrates a back side of the apparatus  20  with a sheet metal cover removed. The apparatus  20  includes a gas powered furnace unit  26 , a ventilating or fan unit  28  including a forced air fan, a cooling evaporator unit  32 , a cooling condenser unit  36  including a refrigerant compressor and an evaporator fan, and a thermostat  44 . The apparatus  20  is mounted on a cart  22  that is supported on caster wheels  23 . 
         [0031]    The condenser unit  36  is piped to the evaporator unit  32  via tubes  50 ,  52  and other components as is known in conventional central air conditioning systems. The tube  50  is shown insulated. The condenser unit  36  is wired for power and control via wires threaded through a conduit  60  and a junction box  62 , as would be found at a typical house installation. 
         [0032]    The furnace unit  26  includes a control printed circuit board  100  having electronic components mounted thereon and which constitutes a central processing unit (CPU). 
         [0033]    According to the invention, the apparatus  20  is modified to provide the capability to cause pre-selected electrical or electronic faults in the control or power circuits for the furnace, cooling and/or ventilating systems. 
         [0034]    According to the invention, conductors  107  within the control or power circuits, or within components, are intentionally disconnected or severed at test connections  106  ( FIGS. 5A and 5B ) creating a pair of severed ends  107   a ,  107   b  ( FIGS. 7A ,  7 B,  7 C) wherein test wires are connected on each side of the disconnection, to each of the ends  107   a ,  107   b  and routed to an instructor&#39;s console  110  in front of the apparatus  20 . The instructor&#39;s console is located such that the student cannot observe the console while working at the back side of the apparatus. 
         [0035]    The test connections  106  can be located within wiring, conductors on the printed circuit board or within components, such as within a winding of a motor. 
         [0036]    The test wires for the condenser unit  36  are routed to the instructor&#39;s console  110  via a conduit  116 . The test wires for the furnace  26  and ventilation unit  28  are routed through a front panel of the furnace through a conduit or wire guide  122 . The conduit  116 ,  122  merge into a conduit or wire guide  126  that extends up to the instructor&#39;s console  110 . 
         [0037]      FIGS. 1-3  illustrate that the apparatus  20  is substantially identical to a commercially available HVAC unit. In that regard the evaporator unit  32  is mounted within an actual air plenum or duct  125  above the fan unit  28 . The furnace unit  26  is also located within the plenum or duct between the evaporator unit  32  and the fan unit  28 . The furnace unit includes an exhaust vent  126 . 
         [0038]      FIG. 4  illustrates the instructor&#39;s console  110  having (28) toggle switches  130  that can be used to initiate faults in the control and power circuits of the apparatus  20 . The following faults can be initiated: 
         [0039]    bad thermostat on heat call, 
         [0040]    bad thermostat on air-conditioning call, 
         [0041]    bad compressor, 
         [0042]    blocked pressure hose, 
         [0043]    bad fan blower, high speed, 
         [0044]    bad contact at condenser  24 /open, 
         [0045]    bad condenser fan motor, 
         [0046]    bad wire to contact number 24V, 
         [0047]    bad wire to furnace on heat call, 
         [0048]    bad wire to furnace on cool call, 
         [0049]    bad fan blower, low speed, 
         [0050]    bad transformer  110  open, 
         [0051]    bad fan blower capacitor, 
         [0052]    call for heat, bad board, 
         [0053]    open neutral to furnace blower, 
         [0054]    limit circuit open, 
         [0055]    bad transformer number  24 , 
         [0056]    no power at induction motor, 
         [0057]    bad dr switch, 
         [0058]    no ground at gas valve, 
         [0059]    open wire to igniter, 
         [0060]    call for air-conditioning bad board, 
         [0061]    open flame sensor, 
         [0062]    bad board, no power to igniter, 
         [0063]    bad board, no power to induction motor, 
         [0064]    no power at pressure switch, 
         [0065]    no neutral lead connection to furnace, and 
         [0066]    no hot lead connection at gas valve. 
         [0067]      FIG. 5A  illustrates places on a furnace unit and ventilating unit connection schematic where the test connections  106  can be made. At each location  106 , the connection detail shown in  FIG. 7A  can be used. Wiring between components can have a test connection or conductors within components can have a test connection such as igniter  129 . Component casings can be opened and test connections created on component conductors. 
         [0068]      FIG. 5B  illustrates places on a condenser unit schematic where the test connections  106  can be made. At each location  106 , the connection detail shown in  FIG. 7A  can be used. Wiring between components can have a test connection or conductors within components can have a test connection such as internal overload trip  131  within compressor motor  133 . Component casings can be opened and test connections created on component conductors. 
         [0069]      FIG. 6  comprises a legend for the symbols used in  FIG. 5A . 
         [0070]      FIG. 5C  illustrates in detail the connections from a thermostat terminal strip  129  to the thermostat  44 . The connections  106  can me made at locations in the wiring from the furnace circuit board  100  to the thermostat  44 , between wires, and within wiring internal to the thermostat  44 . The connections  106  can be according to  FIG. 7A  or alternately  FIG. 7B  or  7 C. Thus, faults can be simulated in the wiring external to the circuit board  100  or thermostat  44  or as a component failure of the thermostat  44 . To simulate the latter, the thermostat is opened up and wires or circuit board conductors are cut or severed and the connections according to  FIG. 7A  or alternately  FIG. 7B  or  7 C are made. 
         [0071]      FIG. 7A  illustrates how each toggle switch  130 , such as each of the (28) toggle switches  130  shown in  FIG. 4 , is placed into the test connection  106 . A test wire  132  and a test wire  134  are connected to the switch  130  below the console  110  and are routed to the respective severed conductor ends  107   a ,  107   b  corresponding to the test connections  106  shown in  FIGS. 5A and 5B . Depending on the state or position of the switch  130 , the conductor ends  107   a ,  107   b  are effectively disconnected (open circuited) at the switch  130  or connected through the switch  130 . 
         [0072]      FIG. 7B  illustrates an alternate embodiment to the arrangement of  FIG. 7A  wherein one a more of the test locations  106  shown in  FIGS. 5A and 5B  can be selectively shorted to ground rather than severed. 
         [0073]      FIG. 7C  illustrates a further alternate embodiment to  FIG. 7A  wherein one or more of the conductors at the test locations  106  shown in  FIGS. 5A and 5B  can have a resistor  136  added. This could simulate a faulty or weakened component, or a bad connection. 
         [0074]      FIG. 8  illustrates a schematic for a domestic appliance in the form of a water heater  150 . Test connections  152  are illustrated and can also use the switch and wiring configuration shown in  FIG. 7A , or alternately  FIG. 7B  or  7 C as applicable. 
         [0075]      FIG. 9  illustrates a schematic for a domestic appliance in the form of an oven  180 . Test connections  182  are illustrated and can also use the switch and wiring configuration shown in  FIG. 7A , or alternately  FIG. 7B  or  7 C as applicable. 
         [0076]      FIG. 10  illustrates a schematic for a domestic appliance in the form of a refrigerator/freezer  200 . Test connections  202  are illustrated and can also use the switch and wiring configuration shown in  FIG. 7A , or alternately  FIG. 7B  or  7 C as applicable. 
         [0077]    According to the each of the embodiments described above, the plurality of switches  130  allow an instructor to select in which circuit of the appliance to simulate a failure by changing the state of the corresponding switch, the selection being hidden from observation by the student. 
         [0078]    The apparatus of the invention comprises an actual domestic appliance such as a furnace, air-conditioner, HVAC unit, water heater, oven or refrigerator that is modified to have open circuits, bad connections or short circuits that are selectable by a plurality of switches located on a back panel or instructor&#39;s console that is hidden from view of the student. 
         [0079]    To further enhance the training of the student, an actual appliance is utilized wherein the environment is identical to what the student would face when making a field service call to repair a malfunctioning appliance. The method of the invention includes the steps of providing an actual domestic appliance and modifying the appliance by disconnecting circuits and reconnecting circuits via wires and switches such that the circuits can be selectively opened by an instructor to simulate failure of a circuit. The disconnections can be within wiring, within conductors on a printed circuit board, or within individual components, such as within windings of a motor. The method can also include the step of adding a resistance to the circuit via the switch and a resistor to simulate a partial failure or a weakened component. The method can also include the step of closing a circuit to simulate a short circuit. 
         [0080]    From the foregoing, it will be understood that numerous variations and modifications may be effected without departing from the true spirit and scope of the novel concept of the invention. It is to be understood that no limitation with respect to the specific method, apparatus, and product illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.