Great Plains PD8070 Operator Manual - Manual (Page 72)

68 PD8070 Table of Contents Index Great Plains Manufacturing, Inc.
401-479M Table of Contents Index 2014-07-23
Ratchet Drives
Refer to Figure 77
Two ratchet assemblies, one on the left side of each
ground drive tower, couple the drive shaft to each ground
drive in forward motion, and de-couple it when the other
ground drive is operating faster (as in tight turns).
Each ratchet must operate freely in forward motion, and
de-couple in reverse. To test it, raise the planter and turn
each ground wheel in reverse.
See “Shaft Alignment” on page 67 if binding is
observed.
Chain Maintenance
Inspect and lubricate chains regularly. The slack of new
chains tends to increase during the first few hours of
operation due to seating. Check slack within the first 8
hours of operation and tighten idlers as necessary.
Refer to Figure 78, which, for clarity, greatly exaggerates
slack, and omits the idlers.
1.
Measure the span for allowable slack:
Locate the longest span of each chain (usually the
span which does not run through the idlers). The
ideal slack is between 2% and 4% of the span.
For example:
A slack of 1cm is appropriate for a 30cm span.
2. Measure the current slack :
Acting at a right angle to the chain span at the center
of the span, deflect the chain in both directions with a
force of about 4 kg (9 pounds).The slack is the
distance of the movement.
3. Adjust the idlers for ideal slack.
Whenever mounting a chain, make sure the clip at the
removable link is oriented to minimize snags.
Refer to Figure 79
Install clip with open end facing away from direction of
chain travel (shown by gray or striped arrows in chain
routing diagrams).
Figure 77
Ratchet Drives
25468
5
5
Figure 78
Measuring Chain Slack
27264
2
1
1
Figure 79
Chain Clip Orientation
26482
2