To improve the structure of a side rail part by setting the cross section of the side rail to a solid closed section structure of an FRP material including a skin material and a core material and changing in the front/rear direction of a truck.
A gate panel 9 opening/closing balancer 41 is fixed to the bottom side of a floor body, the inside face of a side rail 22, or a lateral floor joist and the tip part of its operation rod 42 is rotatably coupled with the gate panel 9 via a coupling member 43. When the panel 9 fitted to the side rail 22 so as to open/close freely is opened, the balancer 41 energizes upward (closed direction) so as to substantially offsets its dead load and operate the panel 9 lightly and easily. The cross section of the side rail 22 of the balancer 41 fitting part has an L-shaped open cross section structure 44 and is provided with an L-shaped FRP material part 45 and a metal reinforcing member 46 embedded therein so as to be insert formed. As a result, this constitution allows the balancer 41 to be fitted easily even in a case of positioned inside the side rail under the floor limited spatially and sufficiently secure the rigidity and durability necessary for respective parts, while securing the light weight performance due to the use of the FRP material.
KIMOTO YUKITANE
KAWANOMOTO YASUYUKI
