3627057 is referenced by 7 patents and cites 6 patents.

A planter row marker includes a safety mechanism for preventing damage during marking operations to the marker arm and supporting structure in case the marker tool or outer portions of the arm should strike a relatively immovable object. The safety mechanism includes a rod which has one end reciprocably received in the bight portion of a spring clevis and a spring pressure nut at the end of the rod holds a compression spring between the nut and the bight of the clevis. The safety mechanism is adapted for use with either nonfolding or folding markers and in the case of the former, the opposite ends of the safety mechanism are pivotally connected to the planter frame and an intermediate point along the marker arm and in the case of the latter, the opposite ends of the safety mechanism are pivotally connected to the inner and outer arms of the foldable arm assembly. The rod of the safety mechanism includes two parts interconnected by a shear pin and should the load on the compression spring reach a predetermined value, the shear pin will break permitting outer sections of the nonfolding and folding marker arms to pivot rearwardly relative to inner arm sections.

Title
Row marker safety mechanism
Application Number
04/869,311
Publication Number
3627057
Application Date
October 24, 1969
Publication Date
December 14, 1971
Inventor
Hansen Harold Valentine
Hartwig Donald R
Assignee
Deere & Company
IPC
A01b 61/00
A01b 35/32
A01B 69/02
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