Down pressure spring adjustment

In a tool supporting rig for an agricultural implement supported from a frame by a parallel bar linkage rockable about a transversely extending axis, the parallel bar linkage including upper and lower links having first ends, first pivot structure connecting the first ends to a first bracket, and second ends connected to a second bracket, a spring tensioning assembly for adjustably biasing the rig a preselected direction, the spring tensioning assembly including:

• an upright notched portion supported adjacent the first pivot structure, the notched portion including notches of preselected configuration;
• a rotatable indexing member including a mating portion generally conforming to at least a portion of the configuration of the notches;
• a down pressure spring connected between the rotatable indexing member and the second bracket, the down pressure spring biasing the mating portion of the indexing member into engagement with one of the notches;
• structure for selectively rotating the indexing member to move the mating portion incrementally along the notches and thereby adjust the tension of the spring;
• wherein the notched portion comprises a pair of transversely spaced edges and the indexing member extends between the edges;
• and
• wherein the spaced edges are integral with the first bracket.

In a tool supporting rig for an agricultural implement supported from a frame by a parallel bar linkage rockable about a transversely extending axis, the parallel bar linkage including upper and lower links having first ends, first pivot structure connecting the first ends to a first bracket, and second ends connected to a second bracket, a spring tensioning assembly for adjustably biasing the rig a preselected direction, the spring tensioning assembly including:

• an upright notched portion supported adjacent the first pivot structure, the notched portion including notches of preselected configuration;
• a rotatable indexing member including a mating portion generally conforming to at least a portion of the configuration of the notches;
• a down pressure spring connected between the rotatable indexing member and the second bracket, the down pressure spring biasing the mating portion of the indexing member into engagement with one of the notches;
• structure for selectively rotating the indexing member to move the mating portion incrementally along the notches and thereby adjust the tension of the spring;
• wherein the notched portion comprises a pair of transversely spaced edges and the indexing member extends between the edges;
• wherein the notched portion comprises a pair of transversely spaced edges and the indexing member extends between the edges;
• and
• wherein the spring is supported outwardly of the first bracket and the first ends of the upper and lower links are supported inwardly of the spring.

In a tool supporting rig for an agricultural implement rockably supported from a frame by a parallel bar linkage for vertical movement, the parallel bar linkage including upper and lower links having first ends pivotally connected to upright plate structure and second ends pivotally connected to the frame, a tool-carrying rig tube connected to the plate structure below the lower link, the links pivoting between a first position corresponding to a transport position of the rig tube and to positions corresponding to field working positions of the rig tube, a spring tensioning assembly for adjustably biasing the rig tube when the rig tube is in the field working positions, the tensioning assembly including:

• an indexing member supported for vertical movement along the plate structure;
• a down pressure spring tensioned between the indexing member and the frame;
• means for moving the indexing member vertically along the plate structure to vary the tension in the spring;
• and
• wherein the plate structure includes a plurality of vertically spaced notches and the down pressure spring biases the indexing member into engagement with the notches.

In a tool supporting rig for an agricultural implement rockably supported from a frame by a parallel bar linkage for vertical movement, the parallel bar linkage including upper and lower links having first ends pivotally connected to upright plate structure and second ends pivotally connected to the frame, a tool-carrying rig tube connected to the plate structure below the lower link, the links pivoting between a first position corresponding to a transport position of the rig tube and to positions corresponding to field working positions of the rig tube, a spring tensioning assembly for adjustably biasing the rig tube when the rig tube is in the field working positions, the tensioning assembly including:

• an indexing member supported for vertical movement along the plate structure;
• a down pressure spring tensioned between the indexing member and the frame;
• means for moving the indexing member vertically along the plate structure to vary the tension in the spring;
• and
• wherein the indexing member extends outwardly from the plate structure and the down pressure spring is located outwardly of the plate structure.

In an agricultural implement having a frame, a linkage having one end pivotally connected to the frame and an opposite end connected to tool support structure, and a spring with proximate and distal ends, the spring connected at its distal end to a spring-mounting location and at its proximate end to the tool support structure for biasing the tool support structure in a preselected direction, tension adjusting structure for varying the bias in the preselected direction, the tension adjusting structure including:

• an indexing area located on the tool support structure and defining discrete locations at varying distances from the spring-mounting location;
• a rotatable member supported by the tool support structure for movement relative to the indexing area and including indexing structure maintaining the rotatable member at one of the discrete locations;
• wherein the proximate end of the spring is connected to the rotatable member for movement therewith relative to the indexing area so that the distance between the distal end and proximate end of the spring and thus the tension in the spring is dependent upon the location of the rotatable member along the path;
• and
• wherein the tension in the spring biases the indexing structure into engagement with the indexing area on the tool support structure and maintains a preselected adjusted tension position independently of additional securing mechanisms.