| 摘要 |
<p>An opener for use in varying ground conditions, ranging from no-till to conventional full tillage conditions, includes an adjustable down pressure control and a down pressure spring and tension link assembly which selectively provide a limited free float opener condition or a conventional down pressure spring controlled bias condition. A sleeve slidably received by the opener arm and mounted over the lower portion of the tension link assembly allows the opener to free float in loose soil conditions so that only the weight of the opener provides downward bias when the down pressure control is adjusted to a minimum condition. The opener is free to ride up and down to follow irregularities in the ground surface. In harder soil conditions such as those encountered in no-till farming methods, the down pressure control is adjusted to a position wherein an enlarged portion on the sleeve bottoms against the opener arm and the spring begins to compress so that the opener operates in the conventional spring biased mode. The sleeve allows increased downward movement of the opener to follow depressions in the soil.</p> |
