| 摘要 |
PURPOSE: To improve safety of a double acting piston cylinder device marking unit by connecting the piston cylinders for the front and rear wheel steerings together with a conduit and, under a normal condition, communicating the conduits together, while, under an abnormal condition, cutting off the communication and changing over the rear wheel steering servo motor to reverse. CONSTITUTION: Under a normal driving condition, a supplementary rear wheel steering device is operated by the operation of a selector valve 27 and a control valve 34. As an abnormality takes place, communication of conduits 15, 16 is cut off as valves 17, 18 close and a piston cylinder 10 is connected to a fluid sump 8 regardless of the position of the control valve 34 as valves 31, 35 open. Thus piston cylinders 5, 9 are made in a positive driving connecting condition by fluid pressure and the front and rear wheel steering devices are simultaneously operated. Driving safety can be improved by this composition. |
