Patent ID: 8033614

Claim:
A transporter vehicle, comprised of: an automotive vehicle body ( 2 ), a loading platform ( 3 ) tiltably mounted on said vehicle body ( 2 ) to carry a load of transportation, an expandable hoist cylinder ( 10 ) connected between said loading platform ( 3 ) and said vehicle body ( 2 ) to lift said loading platform ( 3 ) up to a rearwardly tilted position at a time of dumping said load of transportation from said loading platform ( 3 ), a hydraulic pressure source ( 11 , 12 ) for supplying and discharging pressure oil to and from said hoist cylinder ( 10 ) to elongate and contract said hoist cylinder ( 10 ), and a control valve unit ( 16 ) connected between said hydraulic pressure source ( 11 , 12 ) and said hoist cylinder ( 10 ) to control supply and discharge of pressure oil to and from said hoist cylinder ( 10 ); said control valve unit ( 16 ) being switchable to and from a plural number of positions, including a raising position (b) for raising said loading platform ( 3 ) by extending said hoist cylinder ( 10 ) by supplying and discharging said pressure oil, a lowering position (d) for lowering said loading platform ( 3 ) downward by contracting said hoist cylinder ( 10 ) by supplying and discharging said pressure oil, a floating position (c) for allowing a self-weight fall of said loading platform ( 3 ) by contracting said hoist cylinder ( 10 ) by the self-weight of said loading platform ( 3 ), and a neutral position (a) for stopping a movement of said hoist cylinder ( 10 ) by stopping the supply and discharge of said pressure oil; characterized in that said transporter vehicle further comprises: a position detecting means ( 29 ) adapted to detect to which one of said positions (a) to (d) said control valve unit ( 16 ) is currently shifted; a platform condition detecting means ( 30 , 41 , 51 ) adapted to detect a current posture of said loading platform ( 3 ) on said vehicle body ( 2 ); a vehicle speed detecting means ( 31 ) adapted to detect whether or not said vehicle body ( 2 ) is current in travel; and a control means ( 32 , 42 , 53 ) adapted to switch said control valve unit ( 16 ) from said floating position (c) to said lowering position (d) when it is judged that said control valve unit ( 16 ) is currently in said floating position (c), that said loading platform ( 3 ) floated up from said vehicle body ( 2 ) and that said vehicle body ( 2 ) is currently in travel, on the basis of detection signals from said position detecting means ( 29 ), platform condition detecting means ( 30 , 41 , 51 ) and vehicle speed detecting means ( 31 ).