| 摘要 |
<p>A conversion apparatus is provided for adapting a single-acting lifting cylinder (4) of an agricultural vehicle to a double-acting cylinder. The existing pressurised fluid supply of the vehicle provides a pump (2) supplying the fluid, a tank (3) to receive fluid and coupled to a first chamber (4b) of the cylinder, and a first control valve (30) operable to connect the other chamber (4a) of the cylinder to the pump or the tank. The conversion apparatus provides a second control valve (61) with a check valve (60). A first fluid connection (57) is established from the pump (2) upstream of the first control valve (30) to the second control valve (61), with the check valve (60) configured to oppose fluid flow toward the pump. A second fluid connection (58a-58b) is provided by the second control valve (61) interrupting the connection of the first chamber (4b) to the tank (3), whereby the second control valve (61) is operable to connect the first chamber (4b) to the first fluid connection (57) or the tank (3).</p> |
