| 摘要 |
<p>1. An improved device for preparing the ground by means of a transverse roller mounted on a tractor, adapted to flatten the ground in as uniform a manner as possible between the tracks of the wheels of the tractor, in which the roller (1) is pulled by a coupling (4) connected to the chassis (6) so that it is disposed underneath the tractor behind its front wheels (7B ), and the roller moreover is subjected to the action of a hydraulic operating system (9) which uses jacks (16A , 16B ) controlled by a control system adapted to allow the driver to move the roller to occupy either a raised transporting position or a lowered working position in which the pressure exerted on the ground is derived from the weight of the tractor, characterized in that the roller is situated substantially below the centre of gravity of the tractor, which permits an optimal distribution of the masses, and in that the control system comprises a damping circuit having a nitrogen storage vessel (26) connected to the thrust end of the two jacks (16A , 16B ) of the hydraulic operating system (9) acting on the roller, this circuit comprising, in addition to this storage vessel and a manometer (23) allowing its pressure to be displayed, a valve (22) adapted to connect this thrust end of the jacks and this storage vessel (26) in parallel to the pressure distributor (21) of the tractor, as a result of which the control system is adapted to allow preset control of the pressure exerted by the roller on the ground before work begins by opening the valve (22), then applying a pressure to the damping circuit and the thrust end of the jacks until a chosen pressure is obtained, then closing the valve, and it is also adapted to automatic application of this preset pressure on the roller when the latter is placed on the ground to work on the ground, the storage vessel (26) storing the oil driven back at the thrust end of the jacks in the raised transporting position and restoring it at this end in the lowered position.</p> |
