Abstract:
An aircraft fixed receptacle connector and a ground supply free plug connector used in commercial and military aircraft. This high performance external power connector is capable of operating in the 120 KVA rating to meet the electrical load requirement on today&#39;s newer, larger, and higher capacity aircraft. An array of high amperage power contacts and conventional pin and socket relay contacts are used.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to aircraft connectors for ground electrical supplies. More particularly, the invention relates to an aircraft fixed connector (receptacle) and ground supply free connector (plug) used on commercial and military aircraft. With newer aircraft having higher capacity load, ground power supply and aircraft multiple socket hook-ups are insufficient and inefficient. 
     When a commercial aircraft is docked at the airport and it&#39;s self generating electrical power is shut off, the aircraft is plugged into the airport ground power system. Stated differently, a ground power cart can be connected to the airport power supply system with its ground supply free connector attached to the aircraft fixed connector which is usually mounted and located at the bottom of the exterior forward nose cargo area of the aircraft. Prior art aircraft power connector coupling is basically maintained through the physical engagement between the electrical contact pins on the aircraft&#39;s fixed connector and the electrical contact sockets on the ground supply&#39;s free connector. This coupling interconnection between the aircraft power receptacle and ground power plug is the major cause of failure. The heavy weight of the ground power plug pulling down on the electrical engagement between the pin and socket contacts may cause arcing when power is on. This condition coupled to the frequency of coupling and uncoupling on these connectors will result in eventual electrical breakdown. Other contributors to aircraft power connectors failures are: a) a damaged or worn receptacles or plugs can cause damage to aircraft and ground power units; b) the ground power plug could well be connected to several hundred aircraft receptacles during its life; c) no inspection of either aircraft receptacle or ground power plug before usage; d) no action and/or process to identify aircraft receptacle or ground power plug which may have damaged other aircraft power connectors; e) the environment in which the connectors are used cannot be controlled; f) the aircraft power connectors require considerable force to couple, resulting in incomplete coupling, particularly where this requires lifting the ground power plug above shoulder height; g) the staff or crew connecting the aircraft power connectors may have no electrical knowledge; and h) the standards to which the aircraft power connectors are maintained throughout the world can vary significantly. Replacement of either the aircraft fixed connector and/or ground supply free connector is a significant revenue loss to the airlines and airport. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention in an illustrative embodiment describes 120 KVA aircraft power connectors using a hermaphroditic high amperage power contract, e.g., as shown in U.S. Pat. No. 5,174,777 to Carter, issued Dec. 29, 1992. The present embodiment supplies the electrical ground power needs on the newer, larger and higher capacity load aircraft. Furthermore, the hereinafter described aircraft power connectors ensure full electrical coupling and are self-attaching, which facilitates assembly of ground supply free connectors onto aircraft fixed connectors. 
     It is an object of this invention to overcome the herein above described deficiencies and disadvantages of the prior art. 
     It is another object of this invention to provide a new aircraft fixed connector (receptacle) and ground supply free connector (plug) which are: a) capable of providing a 120 KVA ground power supply with a reliable high electrical bearing interface; b) electrically and mechanically engaged when coupled; c) robust in construction; d) capable of withstanding heavy mechanical shocks and hard wear in use; and e) equipped with a positive coupling arrangement which will release automatically with a simple pull on a wire lanyard without damage to the aircraft fixed connector or its mounting. 
     A further object of this invention is to provide aircraft power connectors which comprise four hermaphroditic high amperage power contacts and two conventional relay contacts and receptacle and plug housing and its components wherein the aircraft fixed connector contains an integral mounting flange with four specially placed panel mounting holes. Also, this integral mounting flange contains another strategically placed hole with provisions for a slide latch fastener. A wire lanyard is attached to the slide latch fastener for releasing the latching pin on the ground supply free connector. The housing proximal end has an extended shroud designed to protect the mating ends of the electrical contacts and is constructed with a keyway. Additionally, boss like creepage barrier tubes independently surround each of the four hermaphroditic high amperage power contacts. Furthermore, attached to the electrical contacts but dielectrically insulated from each other are wire terminal studs with nut, washer and lockwasher. 
     The ground supply free connectors has an extended male boss which surrounds and protects the mating ends of the electrical contacts and has provisions for accepting the boss like creepage barrier tubes surrounding the hermaphroditic high amperage power contacts contained in the fixed connector. This extended male boss which forms part of the ground supply free connector has a matching key which is intended to allow one way assembly between the ground supply free connector and the aircraft fixed connector. This facilitates and eases the considerable force and sometimes blind mate condition when coupling the ground supply free connector onto the fixed connector. An environmentally sealing cable clamp or backshell having a male engagement thread is coupled onto the female thread provided at the distal end of the connector housing. Additionally, a reinforcing integral boss is strategically placed on the housing which accepts an extended but fixed latch pin. A wire lanyard is attached to the sliding latch that is part of the aircraft fixed connector that accepts the latch pin of the ground supply free connector. It can be seen that the mated integrity of the aircraft power connectors is maintained by the latch pin being captivated by the sliding latch. When it becomes necessary to unplug the ground supply free connector, a simple pull on the wire lanyard opens the sliding latch and the aircraft power connectors can be separated. It can also be seen that ground personnel on occasion may forget to disconnect the ground supply free connector as the aircraft begins its taxi to the runway, causing major damage to the ground power cart. The present invention has built-in contingency for releasing the ground supply free connector to the ground when the wire lanyard becomes taut. Another advantage of the present invention is that, realizing the physical abuse and environmental conditions that are normally inherent when using the ground supply free connector, a metal protective cover can be installed to lengthen its durability and life usage. This feature contains a set of plug face covers and trap like doors that open. The doors fully open prior to engagement on the electrical contacts of the aircraft power connectors. 
     A still further object of the present invention is to provide a ground supply free connector having an environmental protective cover which automatically open when being coupled to the aircraft fixed connector and closes when decoupled. 
     It is also an object of this invention to provide aircraft power connectors with replaceable contacts (when damaged or worn out) such that the ground supply free connector cable can be reused or aircraft fixed connector repaired thereby saving labor and time. 
     One embodiment of the present invention is the receptacle connector housing having an extended shroud with boss like creepage barrier tubes and keyway to engage an envelope of plug connector housing having male boss and key. Specifically, boss like creepage barrier tubes and male boss are constructed to protect the high amperage power contacts. Another embodiment is the full mechanical coupling between the aircraft fixed receptacle connector and ground supply free plug connector as provided by having the latch pin in the plug connector in a locked position within the receptacle connector slide latch fastener. These embodiments ensure full electrical contact engagement, user friendly assembly between plug and receptacle connectors, and eliminate prior art short life cycle on the high amperage power contacts. A wire release lanyard is provided in the slide latch fastener to decouple the external power connectors. Additionally, a metal housing comprising a set of doors attached to a set of hinge springs which are connected to a slide link protects ground supply free plug connector from adverse usage and extreme weather conditions. The set of doors is closed when the plug connector is at its uncoupled condition and is open when the plug connector is being coupled to the aircraft fixed receptacle connector. Movement on these doors is initiated by a spring-loaded actuator pin which is mounted in the face of the plug connector. An environmentally sealing backshell threadedly connected on the distal end of the ground supply free plug connector body or housing allows power and relay contacts to be replaced when necessary. Another embodiment of the present invention is the power and relay electrical contacts are replaceable. This property is non-existent in the prior art aircraft external power connector. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIG. 1 is a cross-sectional view of the aircraft fixed receptacle connector illustrating both the hermaphroditic high amperage power contact and the conventional relay contact attached to its wire terminal stud and accessory. Included also is the slide latch fastener. 
     FIG. 2 is a rear (face) view of the aircraft fixed receptacle connector showing the wire terminating studs and its accessory for the four power and two relay contacts, its integral mounting flange with specially located holes for panel mounting, and the slide latch fastener. 
     FIG. 3 is a front (face) view of the aircraft fixed connector illustrating its extended shroud construction and a keyway portion thereof. 
     FIG. 4 is a rear view of cable terminal end of the ground supply free plug connector and a detail view of the slide latch fastener with the latch pin in a coupled position plus a depiction of the wire lanyard mechanism in accordance with the present invention. 
     FIG. 5 is a partly sectional side view of the ground supply free plug connector showing the latch pin, environmentally sealing backshell and the electrical contacts. 
     FIG. 6 is a front (face) view of the ground supply free plug connector showing the plurality of electrical contacts and its extended, keyed, male boss in accordance with the present invention. 
     FIG. 7 is similar to FIG. 4, illustrating the metal protective cover housing. 
     FIG. 8 is similar to FIG. 5 but included is FIG. 8A, a cutaway partial top view, illustrating the mechanism of the spring loaded plug face covers with its trap like doors connected to hinge springs in accordance with the present invention. 
     FIG. 9 is similar to FIG. 6 but with metal protective cover over the engaging face of the ground supply free plug connector. 
     FIG. 10 is an isometric view of the ground supply free plug connector showing the metal protective cover, spring loaded actuator pin, latch pin and FIG. 10A is a cutaway detailed view of the environmentally sealing backshell. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For this description, a 120 KVA aircraft high performance external fixed and ground supply free power connector and its assembly exemplifying the preferred embodiments of the present invention is detailed in FIGS. 1-10. As shown in FIGS. 1-3, the aircraft fixed receptacle connector  1  includes a mating face  24  with extended creepage barrier tubes  24 A. Surrounding and protecting this mating face is an extended shroud  13  that projects beyond the distal ends of the hermaphroditic high amperage power contacts  4  and conventional relay contacts  5 . Within this extended shroud  13  and located at the bottom end is a keyway  14  that is smaller in width than the full length of the extended shroud  13  affording it to be nonsymmetrical. Built into this keyway  14 , at its most forward end, is a raised catch  15  which is adaptable to fit into a recess  23  within the boss  21  of the mating ground supply free plug connector  16 . As shown in FIG. 2, the aircraft fixed receptacle connector  1  contains an integral mounting flange  3 . Molded or drilled into the integral mounting flange  3  are four panel mounting holes  7  that are located in the outer corner of the flange  3  and these holes  7  accept screws which allow the aircraft fixed receptacle connector  1  to be bolted to an aircraft panel  29 . Also molded or drilled into the integral mounting flange  3  is a larger hole  8 . Attached onto the aircraft panel  29  is a slide latch fastener  6  that is placed in front of larger hole  8 . Attached onto the aircraft panel  29  is a slide latch fastener  6  that is placed in front of larger hole  8 . Attached onto the aircraft panel  29  is a slide latch fastener  6  that is placed in front of larger hole  8 . This larger hole  8  accepts the latch pin  18  contained in the ground supply free plug connector  16 . Within the embodiment of the aircraft fixed receptacle connector  1  and referred to earlier are four 120 KVA hermaphroditic high amperage power contacts  4  and two conventional relay pin contacts  5 . These power contacts  4  and relay contacts  5  are captivated within the aircraft fixed receptacle connector  1  by a rear dielectric plate  2  which is held by four screws  12 . On the distal ends of the power contacts  4  and relay contacts  5  are threaded wire terminal studs  36  which penetrate a designated array of holes molded into the rear dielectric plate  2 . Molded onto the back of the rear dielectric plate  2  is a web-like separator  9 . This ensures electrical interference when wired terminal lugs (not shown) are connected to the threaded terminal studs  36  of the power contacts  4  and relay contacts  5  using the washer and lockwasher  10  and hex nut  11 . 
     As can be seen from FIGS. 4-6, the present embodiment of the invention shows a 120 KVA ground supply free plug connector  16  having an extended male boss  21  which surrounds and protects the mating ends of the power contacts  4  and relay contacts  5 , an environmentally sealing backshell  35  and a fixed latch pin  18 . This male boss  21  is configured in a manner which affords a slight interference fit into the extended shroud  13  of the aircraft fixed receptacle connector  1 . At the rear bottom of the male boss  21  is a small cavity  23  that accepts and captures the catch  15  of the extended shroud  13 . Located also at the bottom of the male boss  21  is a key  22  with a width smaller than its full length. This male key  22  engages the keyway  14  in the aircraft fixed receptacle connector  1 . Molded on the uppermost location of the ground supply free plug connector  16  is a reinforce boss  17  that accepts the latch pin  18 . The ground supply free plug connector is coupled to the aircraft fixed receptacle connector  1  and aircraft panel  29 . A wire lanyard  28  is connected to the slide latch fastener  6  that is mounted onto the aircraft panel  29  which engages in a coupled position the latch pin  18  via a machined-in groove  20  at the front end of the latch pin  18 . Within the ground supply free plug connector  16  are four hermaphorditic high amperage power contacts  4 A and two conventional relay socket contacts  26  dimensionally arranged to couple with the power contacts  4  and relay pin contact  5  contained in the aircraft fixed receptacle connector  1 . Surrounding the four power contacts  4 A at their distal, engaging ends are holes  25  with a flat section  27 . These holes  25  accept the creepage barrier tubes  24 A that form part of the mating face  24  of the aircraft fixed receptacle connector  1 . 
     As described above and seen in FIGS. 7-10, the ground supply free plug connector  16  includes the male boss  21 , cavity  23 , key  22 , boss  17 , latch pin  18  with groove  20 , plurality of power  4 A and relay socket  26  contacts, holes  25  with a flat section  27  and the environmentally sealing backshell  35 . This embodiment construction shows a full metal housing  37  designed to withstand physical abuse and extreme weather conditions. This full metal housing  37  totally surrounds the basic dielectric body of the ground supply free plug connector  16 . Additionally, the power  4 A and relay  26  contacts can be protected from the elements described with a metal protective cover having a set of doors  30 . Attached to each door  30  is a hinge spring  32 , both connected to a slide link  31 . Centrally located at the seam of the doors  30  is a semicircular hole through which extends a spring-loaded actuator pin  33 . The spring-loaded actuator  33  is centrally mounted onto a horizontal bar which connects the two side plates of the slide link  31 . When the ground supply free plug connector  16  is coupled to the aircraft fixed receptacle 3  connector  1 , the flat portion of the mating face  24  of the aircraft fixed receptacle connector engages the spring-loaded actuator pin  33  causing it to retract into the basic dielectric body of the ground supply free plug connector  16 . As the spring-loaded actuator pin  33  starts to move back, the slide link  31  simultaneously pulls back, opening the doors  30 . This described movement is completed prior to the coupling of the power contact  4  and relay pin contact  26  in the ground supply free plug connector  16 . At this point it can be readily understood that the male boss  21  of the ground supply free plug connector  16  enters the extended shroud  13  of the aircraft fixed receptacle connector  1 . Subsequently, latch pin  18  enters hole  8  until slide latch fastener  6  snaps into the groove  20  located at the front end of latch pin  18 . In parallel, catch  15  locks into the cavity  23  as the key  22  engages the keyway  14 . At the completion of the described parts movement, the aircraft fixed receptacle connector  1  and the ground supply free plug connector  16  are fully coupled. This condition ensures that the power contacts  4  and  4 A and relay contacts  5  and  26  are in full electrical engagement. When it is necessary to uncouple the ground supply free plug connector  16  from the aircraft fixed receptacle connector  1 , lanyard  28  is pulled and activates slide latch fastener  6  which free up the groove  20  on latch pin  18 . As the ground supply free plug connector  16  separates from the aircraft fixed receptacle connector  1 , spring-loaded actuator pin  33  ejects forward to is normal position. Simultaneously, slide link  31  also moves forward closing the doors  30  and enables the hinge springs  32  to extend to its protracted position keeping the doors  30  closed. Defective power contacts  4  and  4 A and relay contacts  5  and  26  can be easily replaced. To gain access to the defective power and/or relay contacts, screws  34  are removed, allowing the environmentally sealing backshell  35  to be threadedly removed from the ground supply free plug connector housing.