Row unit for agricultural implement

An agricultural row unit for use with a towing frame hitched to a tractor, the agricultural row unit comprising:

• an attachment frame adapted to be rigidly connected to the towing frame;
• a parallel-bar linkage pivotably coupled to the attachment frame;
• a row unit frame having a leading end pivotably coupled to the parallel-bar linkage to permit vertical pivoting movement of the row unit frame relative to the attachment frame;
• an opener device coupled to the row unit frame for forming a furrow;
• a closing-wheel linkage mounted to the row unit frame;
• a pair of closing wheels mounted to the closing-wheel linkage for distributing loosened soil into the furrow;
• a control valve coupled to a fluid supply source for receiving pressurized hydraulic fluid;
• a hydraulic cylinder mechanically coupled to both the row unit frame and the closing-wheel linkage, the hydraulic cylinder being in fluid communication with the control valve and including
• a movable ram having a first end and a second end, the first end being pivotably coupled to the closing-wheel linkage such that movement of the movable ram moves the pair of closing wheels, and
• a hydraulic-fluid cavity for receiving pressurized hydraulic fluid via the control valve, the hydraulic-fluid exerting hydraulic pressure on the second end of the movable ram for exerting a controllable force that pivots the closing wheels downwardly toward the soil;
• and
• a control system coupled to and controllably adjusting the control valve for adjusting the controllable force for different soil conditions.