Device for stabilizing the two lower steering arms of a tractor

A device for stabilizing two lower steering arms of a tractor which are actuatable by a hydraulically operated power lever, comprising:

• a side strut per lower steering arm, said side struts each include a first single-acting hydraulic cylinder;
• a switching assembly enabling the two first single-acting hydraulic cylinders of the side struts to be connected line-wise to the hydraulic power lever, a connection containing means for jointly separating the two first single-acting hydraulic cylinders hydraulically from the power lever;
• a connecting line common to the two first single-acting hydraulic cylinders for connecting with a second line which leads to a second single-acting hydraulic cylinder associated with the power lever;
• a control valve with three ports, a first port serves for establishing a line connection with the second line leading to the second single-acting hydraulic cylinder, a second port providing a connection with a return line leading to a tank and a third port establishing a connection with the first connecting line;
• a first pressure-controlled return valve in the second line leading to the second single-acting hydraulic cylinder of the power lever behind the line connection with the switching assembly, when a pre-determined pressure is exceeded, said first pressure-controlled return valve opens in the direction of the second single-acting hydraulic cylinder and closes in the opposite direction;
• a bypass line leading to the first return valve, a second return valve in said bypass line, said second return valve closes in the direction of the second single-acting hydraulic cylinder and opens in the opposite direction;
• and said control valve designed to assume three switching positions, with all ports being disconnected from one another in a first position, the first port being connected to the third port in a second position and the third port being connected to the second port in a third position.