Abstract: A latch body is mounted on the lower portion of a seat platform of a driver seat. An engaging portion is mounted on the upper portion of a seat frame. When an opening on the top of the seat frame is covered by the seat platform, the latch body engages the engaging portion. The seat frame may be opened and closed to enable inspection of an engine through a top opening by pivoting the seat platform. The seat platform does not vibrate relative to the seat frame due to impacts incurred while traveling. And is not moved by the posture of the operator who performs tasks while sitting on the seat platform. The stability of the seat platform is ensured.

Abstract: A hydraulic circuit enables a plurality of hydraulic actuators to be locked or unlocked at the same time no matter whether control valves controlling pressurized oil feed to the hydraulic actuators are pilot-controlled or not. To this end, the circuit is provided with oil lines leading from hydraulic pumps to an oil reservoir without passing through the control valves and with first and second selector valves 20 and 24 opening or closing the oil lines.

Abstract: A work vehicle (2) having an implement position controller (50). Set elevations and orientations of the work implement (5) can be preselected and changed. The controller (50) automatically positions the implement (5) in the desired elevation and orientation. Means (51) for preventing the work implement (5) from falling into the ground are also provided.