m end in said slot. hinge on said floor section: 20 (A) a torsion bar extending beneath the level of said R f s Ct d floor parallel to said side wall and including a crank e erence l e arm at each UNITED STATES PATENTS (B) a link 1,247,687 11/1917 Just 1680 (1) pivotally connected at its upper end to the 5 2,075,449 3/1937 McMahon 296 24 underside of said floor section at a location 2,602,957 7/ 1