Compact cargo lift for commercial aircraft

Abstract

An apparatus for transferring cargo between an upper, passenger deck and a lower, cargo deck of an aircraft. A lift platform raises palletized cargo from the lower deck through an opening formed in the upper deck. The drive mechanism is housed entirely within the lift platform itself. The platform is stabilized by flanking, scissors-action leg assemblies, that nest alongside the platform when stowed. The platform is stowed in the raised position, within the opening formed in the upper deck. Locking assemblies attach the lift platform to the sides of the opening so that the platform becomes a load-bearing structural component of the upper deck when stowed. A recess is formed in the lower deck for receiving the lift platform when lowered. A translating floor assembly having folding floor sections lowers to clear the recess, and then raises to define a floor surface over the opening when the lift platform is not in use.

1 . An apparatus for transferring cargo between an upper deck and a lower deck of an aircraft, said apparatus comprising:
 a lift platform that is receivable in a through opening formed in said upper deck of said aircraft, said lift platform having an upper surface for supporting a load of cargo thereon;   means for lowering and raising said lift platform between said upper deck and said lower deck so as to transfers loads of cargo to and from said upper deck via said through opening; and   means for selectively attaching edges of said lift platform to said upper deck in load-bearing engagement therewith when said lift platform is raised and stowed in said through opening, so that said lift platform shares structural loading of said upper deck during flight operation of said aircraft.   
     
     
         2 . The apparatus of  claim 1 , wherein said means for selectively attaching edges of said lift platform to said upper deck in load-bearing engagement therewith comprises:
 means for selectively attaching first and second longitudinally extending side edges of said lift platform to first and second longitudinally extending side edges of said through opening, so that said lift platform shares structural loading of said upper deck in a lateral direction during flight operation of said aircraft.   
     
     
         3 . The apparatus of  claim 2 , wherein said means for selectively attaching said side edges of said lift platform to said side edges of said through opening comprise:
 at least one lock assembly on each of said side edges of said lift platform, each lock assembly comprising:
 a first lock portion that is mounted to a longitudinal side edge of said lift platform; and 
 a second lock portion that is mounted to a longitudinal side edge of said through opening for establishing load-bearing engagement with said first lock portion on said lift platform. 
   
     
     
         4 . The apparatus of  claim 3 , wherein said second lock portion comprises a pin member that extends in a lateral direction from a side edge of said through opening and said second lock portion comprises a rotating latch that receives said pin member in lateral and vertical load-bearing engagement therewith. 
     
     
         5 . The apparatus of  claim 3 , wherein said side edges of said through opening span a plurality of truncated lateral beams of said upper deck, and wherein said lift platform comprises:
 a plurality of lateral beams that span a width of said lift platform and that are aligned axially with said truncated beams of said upper deck when said lift platform is raised and stowed in said through opening.   
     
     
         6 . The apparatus of  claim 5 , wherein said at least one lock assembly comprises:
 a plurality of said lock assemblies, each said lock assembly being located at an axial juncture between one of said truncated beams of said upper deck and one of said lateral beams of said lift platform when said lift platform is raised and stowed in said through opening.   
     
     
         7 . The apparatus of  claim 6 , further comprising:
 longitudinally extending header members mounted across said ends of said truncated beams of said upper deck, and to intact lateral beams of said upper deck at forward and after ends of said through opening.   
     
     
         8 . The apparatus of  claim 1 , wherein said means for lowering and raising said lift platform comprises:
 a lift mechanism comprising:
 at least one lift cable; and 
 a drive assembly for selectively extending and retracting said lift cable so as to lower and raise said lift platform; 
 substantially the entirety of said drive assembly being housed within said lift platform. 
   
     
     
         9 . The apparatus of  claim 8 , wherein said drive assembly comprises:
 an anchor point for an end of said at least one lift cable;   at least one ball screw and nut in cooperating drive engagement, said ball nut being located a spaced distance from said anchor point;   at least one pulley mounted to said ball nut, said lift cable being routed over said pulley from said anchor point; and   a motor for reversibly rotating said ball screw, in a first direction that shortens said distance between said pulley and said anchor point so as to extend said cable from said lift platform, and in a second direction that increases said distance between said pulley and said anchor point so as to retract said cable into said lift platform.   
     
     
         10 . The apparatus of  claim 9 , wherein said at least one ball screw and nut are mounted to extend generally horizontally within an interior height of said lift platform. 
     
     
         11 . The apparatus of  claim 8 , further comprising:
 means for stabilizing said lift platform as said lift platform is lowered and raised between said upper and lower decks of said aircraft.   
     
     
         12 . The apparatus of  claim 8 , wherein said means for stabilizing said lift platform comprises:
 first and second scissors-action stabilizer assemblies on longitudinally extending sides of said lift platform, each said stabilizer assembly comprising:
 at least one pair of rigid arm members joined in an X-shaped configuration by a central pivot point; 
 first and second upper attachment points on said arm members that are pivotably mounted to said upper deck of said aircraft; and 
 first and second lower attachment points on said arm members that are pivotably mounted to said longitudinally extending sides of said lift platform. 
   
     
     
         13 . The apparatus of  claim 12 , wherein said first and second attachment points on said arm members each comprise:
 a stationary pivot connection; and   a sliding pivot connection that accommodates increases and decreases in distance between said first and second attachment points as said lift deck is raised and lowered.   
     
     
         14 . The apparatus of  claim 13 , wherein said sliding pivot connections each comprise:
 at least one guide rail that extends in a substantially horizontal direction;   a bracket member having at least one channel portion that receives said guide rail in sliding engagement therewith, so that said bracket member is free to slide horizontally while being supported vertically; and   a pivot connection joining an end of one of said rigid leg members to said bracket member.   
     
     
         15 . The apparatus of  claim 13 , further comprising:
 first and second spaces formed intermediate said longitudinally extending side edges of said lift platform and longitudinally extending edges of said through opening, in which said rigid leg members of said stabilizing assembly nest when said lift platform is raised and stowed in said through opening.   
     
     
         16 . The apparatus of  claim 8 , wherein said means for stabilizing said lift platform comprises:
 first and second stabilizer legs for extending substantially vertically between said upper and lower decks; and   first and second guide members that are mounted to said lift platform and that are in longitudinal sliding engagement with said stabilizer legs.   
     
     
         17 . The apparatus of  claim 16 , wherein said first and second stabilizer legs comprise:
 first and second elongate leg members that are selectively pivotable from a first, horizontal position in which said leg members nest alongside said lift platform when said lift platform is in said raised and stowed position; and a second, vertical position in which said leg members stabilize said lift platform as said lift platform is lowered and raised between said upper and lower decks.   
     
     
         18 . The apparatus of  claim 1 , further comprising:
 a recess in said lower deck of said aircraft for receiving said lift platform therein, so that said upper surface of said lift platform extends substantially flush with an upper surface of said lower deck when said lift platform is lowered therein.   
     
     
         19 . The apparatus of  claim 18 , wherein said recess in said lower deck of said aircraft comprises:
 an area of said lower deck of said aircraft in which upper edges of floor frames have been removed so as to form said recess therein.   
     
     
         20 . The apparatus of  claim 19 , further comprising:
 a translating floor assembly mounted in said area of said lower deck of said aircraft, said translating floor assembly having a first position which defines a floor surface that extends over said recess generally flush with said upper surface of said lower deck, and a second position which clears said recess for receiving said lift platform in said lower deck of said aircraft.