| 摘要 |
Most presently known crop harvesting attachment flotation apparatus use a spring to preload the attachment into a floating mode. A problem with this is that, as the attachment is either forced upwardly or intentionally raised, the effectiveness of the spring decreases. This is avoided by a combination of a spring and a fluid operated cylinder acting through pivotal linkage relationships for retaining the attachment in a substantially constant flotation mode during lifting operations and during flotation operations.
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