| 摘要 |
An apparatus for varying the rate of seed population by planters or drills, comprising first and second squeeze jack variable speed pulleys, and a belt running around the pulleys; a cog mounted on the first pulley and a cog mounted on the second pulley, and a drive chain running around the cog mounted on the first pulley and a row unit chain running around the cog mounted on the second pulley; and apparatus to vary selectively the speed of the row unit chain at any given speed of the drive chain and at any slope of the apparatus above or below level ground.
|
