Fork lift apparatus adapted to be coupled to a truck or trailer

Abstract

A fork lift with retractably extendable loading prongs for lifting loads from either side of a vehicle. The fork lift includes a mechanism for displacing the prongs over and across the vehicle, which mechanism has front and rear transverse girders which can be rigidly secured to the vehicle's chassis. The mechanism further includes front and rear masts, sprocketed wheels mounted on the masts to move the front and rear masts reciprocally, and a longitudinal beam which is coupled to the masts. The longitudinal beam can move up and down. Front and rear uprights extend downwardly from the longitudinal beam. The prongs are retractably engaged to the bottom of the uprights and are moved with hydraulic pistons.

1. A fork lift comprising retractably extendible loading prongs for lifting loads from either side of a vehicle, and a mechanism for displacing said prongs over and across said vehicle, said mechanism for displacing said prongs comprising:
 a front transverse girder and a rear transverse girder, said transverse girders adapted to be rigidly secured to a chassis of said vehicle;   a front mast and a rear mast, each of said masts extending generally horizontally and having a top and a bottom;   means for simultaneously reciprocating said front and rear masts at their bottoms along said front and rear girders, respectively;   a longitudinal beam coupled to said front and rear masts;   means for reciprocating said longitudinal beam in a downward-upward motion along said front and rear masts; and   a front upright and a rear upright, each of said uprights extending downward from said horizontal beam, wherein at least one of said retractable extendible prongs extends from each of said uprights.   
     
     
       2. A fork lift as in  claim 1 , wherein said prongs comprise front and rear transverse prongs retractably engaged to the bottoms of said front and rear uprights, correspondingly, and means for extending said front and rear transverse prongs from said front and rear uprights, correspondingly, toward either side of said vehicle. 
     
     
       3. A fork lift as in  claim 2 , wherein said beam comprises means for lowering or raising said front or rear uprights. 
     
     
       4. A fork lift as in  claim 2 , wherein said means for simultaneously reciprocating said front and rear masts along said front and rear girders, comprise sprocket wheels, wherein at least one sprocket wheel is mounted on each mast and is turned against mating toothed sprocket bars which are mounted on said front and rear girders, respectively. 
     
     
       5. A fork lift as  claim 4 , wherein said sprocket wheels are propelled by a hydraulic drive. 
     
     
       6. A fork lift as in  claim 2 , comprising a boom to which said front and rear masts are coupled at their tops. 
     
     
       7. A fork lift as in  claim 6 , wherein said means for reciprocating said longitudinal beam in a downward-upward motion comprises front and back hydraulic pistons mounted on said boom, wherein each piston is coupled to a chain which is connected to said beam, through a system of pulleys. 
     
     
       8. A fork lift as in  claim 2 , wherein said means for extending said front and rear transverse prongs from said front and rear uprights, comprises sprocket wheels, each having a hydraulic drive, wherein each sprocket wheel is mounted on each upright and is turned against mating toothed sprocket bars which are mounted on said front and rear transverse prongs. 
     
     
       9. A fork lift as in  claim 2 , wherein said beam comprises means for longitudinally moving said front or rear uprights along said beam. 
     
     
       10. A fork lift as in  claim 9 , wherein said means for longitudinally moving said front or rear uprights along said beam comprises hydraulic pistons. 
     
     
       11. A method of lifting loads from either side of a vehicle, said method comprising the steps of:
 providing a fork lift that comprises
 a front transverse girder, and 
 a rear transverse girder, said transverse girders adapted to be rigidly secured to a chassis of said vehicle, 
 a front mast and a rear mast, each of said masts extending generally vertically and having a top and a bottom, 
 means for simultaneously reciprocating said front and rear masts at their bottoms along said front and rear girders, respectively, 
 a longitudinal beam coupled to said front and rear masts, 
 means for reciprocating said longitudinal beam in a downward-upward motion along said front and rear masts, 
 a front upright and a rear upright, each of said uprights extending downward from said longitudinal beam, and 
 retractably extendable loading prongs, at least one of said retractably extendable prongs extends from each of said uprights and said prongs comprise split prongs adapted to lift two wheels of a car; 
   rigidly securing said fork lift to said vehicle;   horizontally extending the retractably extendable loading prongs over and across said vehicle;   vertically lowering said prongs to the ground;   positioning said prongs securely underneath a load to be lifted;   vertically raising said prongs with the load;   displacing said prongs with the load over and across said vehicle; and   vertically lowering said prongs to rest the load on said vehicle.   
     
     
       12. A method of lifting vehicles having front wheels and rear wheels from either side of a second vehicle with a fork lift, the fork lift including at least one retractably extendible loading prong and a mechanism that displaces the at least one prong, the mechanism including a first transverse girder and a second transverse girder, a first mast having a top and a bottom and a second mast having a top and a bottom, a beam coupled to the masts, at least one member, having a first member and a second member, extending from the beam, a first sub-mechanism, and a second sub-mechanism, the at least one prong having a first split prong and a second split prong, the first split prong extends from the first member, the second split prong extends from the second member, the method comprising:
 securing the first and second girders to the vehicle;   displacing the at least one prong over and across the vehicle with the mechanism;   simultaneously reciprocating the first and second masts at their bottoms along the girders with the first sub-mechanism;   reciprocating the beam along the first and second masts with the second sub-mechanism; and   lifting the vehicle from either side of the second vehicle with the at least one prong by
 (i) engaging the first split prong and the front wheels at a first location and a second location; and 
 (ii) engaging the second split prong and the rear wheels at a first location and a second location. 
   
     
     
       13. The method of claim 12, wherein the simultaneously reciprocating the first and second masts at their bottoms along the girders with the first sub-mechanism comprises turning a sprocket wheel against a mating toothed sprocket bar. 
     
     
       14. The method of claim 13, further comprising turning the sprocket wheel against the mating toothed sprocket bar with a hydraulic drive. 
     
     
       15. The method of claim 12, wherein the reciprocating the beam along the first and second masts with the second sub-mechanism comprises operating a hydraulic pulley system. 
     
     
       16. The method of claim 12, wherein the displacing the at least one prong over and across the vehicle comprises turning a sprocket wheel against a mating toothed sprocket bar with a hydraulic drive. 
     
     
       17. The method of claim 12, comprising translating the at least one member. 
     
     
       18. The method of claim 12, comprising angularly moving the at least one member. 
     
     
       19. The method of claim 12, comprising angularly moving the first and second members.