摘要 |
<p>A variable ratio drive (114) for agricultural seed drills (100) comprises an input shaft (124) carrying four cams (126) acting on respective chains (128) tensioned by springs (130) and driving an output shaft (148) through respective one way clutches (146). Variation of the transmission ratio is achieved by position-adjustement of the chain ends (132) in an arc between positions (A) and (B) by means of a screw threaded manual adjuster mechanism (134). This varies the effective displacement of the chains by their cams.</p> |