Mobile Emergency Medical Vehicle

FIG. 1 is a perspective view of a mobile emergency medical vehicle constructed in accordance with the present invention.

FIG. 2 is a fragmentary side elevational view of the vehicle shown in FIG. 1 illustrating the mounting of the auxiliary engine and electrical generating means in a lower separate compartment of the vehicle.

FIG. 3 is a schematic electrical diagram illustrating the electrical circuitry of the vehicle of the present invention.

The emergency medical vehicle of the present invention designated by the numeral 10 is built on a conventional truck chassis having the main transport engine located beneath the hood as well known in the art. The patient module 11 is mounted on the rearward portion of the truck chassis as well known in the art. However, in accordance with the present invention the module is essentially self-supporting with regard to its electrical requirements. As is conventional in the case of the truck chassis which is conventionally used in constructing Type I ambulances, the transport engine is equipped with a heavy-duty alternator and dual electrical storage batteries which are mounted under the hood. One battery serves to start the transport engine and the other battery serves to provide auxiliary power to the vehicle. Previously, in known types of ambulances, the second battery serves to power the auxiliary equipment including the emergency vehicle lighting and interior lighting of the patient module. In accordance with this invention the auxiliary battery mounted adjacent the main truck engine serves only to supply a back-up portion of the electrical needs to the module in the event its self-contained electrical generating capacity is unable to satisfy the electrical requirements of the module.

As shown in FIGS. 1 and 2, a separate lower compartment 12 of the module is utilized to mount an auxiliary engine and an electrical generator powered by such engine in such compartment. A preferred type of generator power source is one of the so-called "gen sets" of the Onan Corporation which are designed for underfloor mounting in an individual compartment adjacent a rearward portion of the truck chassis. A preferred type of such generator is one capable of producing 4000 watts of power at 120 volts AC, 33.3 amperes, 60 hertz, in single-phase output on a two-wire system. The generator is preferably powered by a four-cycle, two-cylinder horizontally opposed engine which is capable of being started by a 12 volt battery preferably the starting battery of the truck main engine. The generator may also be one capable of supplying 6000 watts where greater capacity is needed.

The auxiliary engine and generator 14 are preferably combinedly mounted on a skid-type mounting frame 13 fitted within the compartment 12 for ready slide-out removal of the unit for servicing and inspection. The auxiliary engine and generator are mounted exteriorly of the patient module so that its exhaust system extends outwardly and delivers minimal noise and vibration to the patient module.

The electrical output of the generator preferably power is capable of continuously delivering 115 capable of providing 4.0 to 6.0 kilowatts of continuous electrical volt AC power to the electrical load center of the module designated by the numeral 15 on FIG. 3. The load center provides distribution of the primary output of the generator 14 to air conditioning and heating means designated by the numeral 17 which are capable of supplying both cooling and heating to the patient module. The module is preferably insulated to minimize temperature fluctuations within the module and to facilitate most efficient cooling or heating as desired. The generator which is preferably located on the passenger side at a rear lower corner of the vehicle provides module power for emergency lights, air conditioning, heating, suction, interior lights, and the like. The air conditioner is electrically operated on 115 volt AC power and has its condensor mounted in a separate lower compartment beneath the module for dispelling heat to the exterior when operated in its cooling mode. The electrical heater consists of 115 volt AC strip heaters which are mounted in spaced locations within the module to supply heating as desired. The load center 15 also supplies a plurality of 115 volt AC receptacles 17 within the module to permit plugging in a wide variety of medical equipment, including newer types of vacuum pumps, requiring such electrical power. The load center 15 also contains an AC to DC electrical converter 19 which converts a portion of the generator output to the 12 volt DC power normally required by both the exterior and interior lighting of the vehicle. The DC power supply is wired to deliver such 12 volt DC power to an emergency transfer and control panel located within the module, such panel being designated by the numeral 20. The panel is capable of supplying main DC power designated by the numeral 21 to the module which includes the minimal exterior lighting required to designate the vehicle as an ambulance and powers both front and rear beacons, sirens, flashers, and lighting strips on the vehicle. The electrical converter 17 preferably consists of an 85 ampere AC to DC power supply to provide 12 volt DC lighting to the emergency indicating lights and interior 12 volt DC fluorescent lights within the module. All such exterior lighting is in accordance with federal specifications for Type I ambulances as set forth in federal specification No. KKK-A-1822B dated June 1, 1985. The control panel 20 also supplies auxiliary 12 volt DC power designated by the numeral 22 to the vehicle for energizing strobe lights, and controls load lights, door warning lights, step lights, and auxiliary dome lights. All electrical circuits within the module are wired in accordance with National Electrical Code specifications and are normally recessed inside the module and ceiling or mounted exteriorly of the walls in surface conduit. The electrical circuits, relays, breakers, and terminal strips are located in a metallic enclosure accessible from within the module with individual controls located on the outer surface of the panel for individual control.

The module interior is also equipped with vacuum generating equipment which may be wired directly into the 12 volt DC circuit or be capable of plugging into such electrical outlets provided interiorly. The vacuum is normally provided by a vacuum pump powered by such 12 volt DC power although it may also consist of a suction unit which may be plugged into the 115 volt AC receptacles 13 within the module.

The module is wired with electrical interconnection between the emergency transfer and control panel 20 and the auxiliary battery associated with the transport engine of the vehicle. An automatic relay 23 is adapted to be operated upon failure of the electrical generator of the module or its auxiliary engine, such that discontinuance of the 12 volt DC lighting and vacuum pump power might result. In the event of failure of such module electrical power the relay 23 automatically switches the main 12 volt DC power requirements of the module including at least a portion of the exterior and interior lighting of the module and the vacuum pump requirements to the auxiliary battery of the vehicle. Such switching of the power source from the module to the electrical charge storage system of the vehicle provides backup power to the essential elements of the vehicle which must be maintained in continuous operation during a medical mission. Only a portion of the DC power requirements of the module are energized by the vehicle auxiliary battery or main engine alternator such as approximately one-half of the normal current load which permits continuous operation of the essential medical equipment and emergency indicating lighting elements of the vehicle.

The utilization of the emergency transfer relay is designed to automatically transfer at least a portion of the essential 12 volt DC systems such as front and rear beacons, four or more interior fluroescent lights, vacuum pump, and the like, to the chassis DC alternator or battery in the event of a generator failure or interruption in its power supply. The emergency transfer relay is a double pole, double throw type such as Model No. PRD 11D40, manufactured by Potter & Brumfield Company. Such relay has reinforced screw terminals and a plastic enclosure around the coil being UL and CSA listed. The use of a double pole, double throw relay allows the ampacity to be distributed between two sets of contacts allowing about 40 percent longer service life to the relay.

The onboard electrical generating capability of the module permits discontinuance of operation of the main transport engine when standing at the site of a medical mission or when servicing or inspecting the module for proper performance. The main truck engine may be either gasoline or diesel powered without having any effect on operation of the module and the auxiliary engine of the module may also be either gasoline or diesel operated as desired or required. Obviously greater or lesser electrical generating capacity may be utilized for supporting the electrical requirements of the module; however, the 4.0 kilowatt generator referenced above has been found to provide adequate electrical capacity for Type I ambulances.

The module may be readily remounted onto a second truck chassis with the only interconnection being the electrical line from the truck main engine electrical system. The module may be serviced by operating its generator and checking its electrical systems and/or operating its cooling or heating systems during such servicing. Obviously, a by-pass can be provided to furnish 115 volt AC power to the module from a supplemental source during servicing without operating the module generator. The main fuel tank of the vehicle is used to supply both main and auxiliary engines where they have similar fuel requirements.

Various modifications may be resorted to within the spirit and scope of the appended claims.