New Holland 499 Operator's Manual page 45

Rolls in Home Position
Rolls are at zero degrees (home position). Link is
straight. This allows full pressure of torsion bar to be
applied to top roll arm.
Rolls Open at 15 Degrees
Rolls begin to open as crop enters conditioning
system. Link starts to bend to rear while torsion bar
maintains conditioning pressure.
Rolls Fully Open at 27.3 Degrees
Rolls are now fully open due to crop slug or foreign
object entering rolls. The link between torsion bar
and top roll arm is no longer applying direct pressure
to roll arm. Rolls are against stop link back with
conditioning pressure now removed. Rolls will return
to former position (with preset conditioning pressure)
when object or slug passes through.
SECTION 2 - OPERATION
50051184
50051185
50051186
2-17
21
22
23