Vehicle mounted fork lift and method

Abstract

A fork lift apparatus is mounted on a truck for picking up a load, placing the load in a traveling position on the truck, and for unloading the load. The apparatus comprises a lift frame, a shaft, a pair of spaced arms secured to the shaft, a cross member spanning between the distal ends of the arms distal and carrying the forks. The cross member is rotatable relative to the support arms. A pair of drive hydraulic cylinders rotates the shaft and thus moves the arms and the load between a loading/unloading position in which the load may be placed on the forks and the traveling position so that the load may be transported by the truck. A self-leveling system is provided for maintaining the load in a substantially level position as it moves between its loading/unloading and traveling positions.

What is claimed is: 
     
         1 . An apparatus for lifting a load on and off a truck, the apparatus comprising:
 a lift frame positioned on a bed of the truck;   a pair of side arms rotatably coupled to the lift frame;   a cross member rotatably coupled to each of the pair of side arms; and   a pair of forks, wherein each of the pair of forks has an end coupled to the cross member,   wherein a top surface of each of the pair of forks is below a top surface of the lift frame when the load is on the bed of the truck.   
     
     
         2 . The apparatus of  claim 1 , further comprising:
 a load platform placed on a top of the lift frame, wherein the load rests on the load platform.   
     
     
         3 . The apparatus of  claim 2 , wherein the load platform comprises:
 a bed plate;   a plurality of plate channels secured to a bottom of the bed plate; and   a pair of fork channels secure to a bottom of each of the plurality of plate channels,   wherein the bottoms of the plurality of plate channels are placed on the top of the lift frame.   
     
     
         4 . The apparatus of  claim 3 , wherein the lift frame comprises a pair of transverse frame members and a pair of longitudinal frame members, wherein each transverse frame member is connected to the pair of longitudinal frame members, wherein each of the pair of longitudinal frame members is parallel to each of the pair of fork channels. 
     
     
         5 . The apparatus of  claim 4 , wherein each of the pair of longitudinal frame members is between the pair of fork channels. 
     
     
         6 . The apparatus of  claim 2 , further comprising:
 a latch member coupled to the lift frame, wherein the latch member is configured to secure the load platform to the lift frame.   
     
     
         7 . The apparatus of  claim 6 , further comprising:
 a latch assembly comprising:
 a latch frame connected to the lift frame; and 
 the latch member pivotally mounted to the latch frame, wherein the latch member is configured to extend through an opening in a fork channel of the load platform to secure the load platform to the lift frame. 
   
     
     
         8 . The apparatus of  claim 1 , wherein lift frame is between the pair of forks when the load is on the bed of the truck. 
     
     
         9 . The apparatus of  claim 1 , wherein each of the pair of forks is coupled to the cross member at locations on the cross member that are between the pair of side arms. 
     
     
         10 . The apparatus of  claim 1 , configured such that each of the pair of forks is in a level position when lifting the load on and off the truck. 
     
     
         11 . The apparatus of  claim 1 , wherein the truck is a flatbed truck or a pickup truck. 
     
     
         12 . An apparatus for lifting a load on and off a truck, the apparatus comprising:
 a lift frame positioned on a bed of the truck;   a pair of side arms rotatably coupled to the lift frame;   a cross member rotatably coupled to each of the pair of side arms;   a pair of forks, wherein each of the pair of forks has an end coupled to the cross member;   a load platform placed on a top of the lift frame, wherein the load rests on the load platform; and   a latch member coupled to the lift frame, wherein the latch member is configured to secure the load platform to the lift frame.   
     
     
         13 . The apparatus of  claim 12 , wherein the load platform comprises:
 a bed plate;   a plurality of plate channels secured to a bottom of the bed plate; and   a pair of fork channels secure to a bottom of each of the plurality of plate channels,   wherein the bottoms of the plurality of plate channels are placed on the top of the lift frame.   
     
     
         14 . The apparatus of  claim 13 , wherein the lift frame comprises a pair of transverse frame members and a pair of longitudinal frame members, wherein each transverse frame member is connected to the pair of longitudinal frame members, wherein each of the pair of longitudinal frame members is parallel to each of the pair of fork channels. 
     
     
         15 . The apparatus of  claim 14 , wherein each of the pair of longitudinal frame members is between the pair of fork channels. 
     
     
         16 . The apparatus of  claim 12 , further comprising:
 a latch assembly comprising:
 a latch frame connected to the lift frame; and 
 the latch member pivotally mounted to the latch frame, wherein the latch member is configured to extend through an opening in a fork channel of the load platform to secure the load platform to the lift frame. 
   
     
     
         17 . The apparatus of  claim 12 , wherein lift frame is between the pair of forks when the load is on the bed of the truck. 
     
     
         18 . The apparatus of  claim 12 , wherein each of the pair of forks is coupled to the cross member at locations on the cross member that are between the pair of side arms. 
     
     
         19 . The apparatus of  claim 12 , configured such that each of the pair of forks is in a level position when lifting the load on and off the truck. 
     
     
         20 . The apparatus of  claim 12 , wherein the truck is a flatbed truck or a pickup truck.