Running fork type load transfer apparatus

Claim 1

A running fork type load transfer device comprising a fixed fork, a secondary fork, and a primary fork, each of said forks having a front end and a rear end, said secondary fork having an idler each at its front and rear ends, said forks being disposed horizontally movably one above another, means for moving said secondary fork and said primary fork, said secondary fork being adapted to telescope in and out of the fixed fork and said primary fork being adapted to telescope in and out of said secondary fork, first and second motion transmitting flexible means for telescoping said primary fork in and out relative to said secondary fork, each of said first and said second flexible means connecting said forks to each other with the respective ends of said flexible means being connected from a respective given end of said fixed fork and of said primary fork which is a same respective given end, a part of each of said flexible means intermediate its ends passing around a respective idler on said secondary fork which respective idler is disposed in each case at an opposite end to said given end, wherein said secondary fork is an aluminum extrusion having therein integral right and left portions each including an outward guide groove, right and left inward guide groove, and upper and lower cavities, a first pair of guide rollers attached to said to fixed fork and arranged to roll within said outward guide grooves, and a second pair of guide rollers attached to said primary fork and arranged to roll within said inward guide grooves, said motion transmitting flexible means being disposed for passing within said upper and lower cavities.